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Technical Information Report PSE Energize Eastside – Renton Segment Renton, Washington December 29, 2020 Updated March 18, 2021 - V3 Technical Information Report PSE Energize Eastside – Renton Segment ii | December 29, 2020 Table of Contents Introduction .................................................................................................... 1 1.0 Project Overview.................................................................................... 1 1.1 Project Description ................................................................................................ 1 1.2 Purpose ............................................................................................................... 10 1.3 Existing Site Conditions ....................................................................................... 10 1.4 Existing Soil Conditions ....................................................................................... 10 1.5 Proposed Site Conditions .................................................................................... 10 2.0 Conditions and Requirements Summary .............................................. 17 2.1 Requirements Summary ...................................................................................... 17 2.2 Stormwater Requirements Assessment .............................................................. 17 3.0 Offsite Analysis .................................................................................... 22 3.1 Level 1 Downstream Analysis ............................................................................. 22 4.0 Flow Control, Low Impact Development (LID), and Water Quality Analysis and Design ....................................................................................... 22 4.1 Existing Site Hydrology ....................................................................................... 22 4.2 Developed Site Hydrology ................................................................................... 22 4.3 Performance Standards ...................................................................................... 22 4.4 Flow Control System ........................................................................................... 23 4.5 Water Quality System .......................................................................................... 23 5.0 Conveyance System Analysis and Design ............................................ 23 6.0 Special Reports and Studies ................................................................. 23 7.0 Other Permits ....................................................................................... 23 8.0 CSWPP Analysis and Design ................................................................. 24 8.1 Erosion Sediment Control (ESC) Plan and Analysis Design ............................... 24 8.2 Stormwater Pollution Prevention and Spill Control Plan (SWPPS) ..................... 25 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant .... 26 10.0 Operations and Maintenance Manual ................................................... 26 11.0 References ........................................................................................... 26 List of Tables Table 1. TDA and Drainage Basin ............................................................................................. 11 Table 2. Land Disturbance and Impervious Area by Proposed Work ........................................ 11 Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | iii Table 3. Summary of Core Requirements ................................................................................. 19 List of Figures Figure 1-1. TIR Worksheet ............................................................................................................ 3 Figure 1-2. Drainage Basins, Subbasins, and Site Characteristics ............................................ 13 Figure 1-3. Soils Map .................................................................................................................. 15 Figure 2-1. Drainage Review Flow Chart ................................................................................... 18 Appendices Appendix A – CSWPP and ESC Plans Appendix B – Critical Areas Report Appendix C – Wellhead Protection Areas Appendix D – Bond Quantities Appendix E – Declaration of Covenant Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 1 Introduction The purpose of this technical memorandum is to facilitate the permit coordination and approval process between Puget Sound Energy (PSE), HDR Engineering Inc. (HDR), and the City of Renton (City) related to improvements proposed by PSE for a substation upgrade and a 16-mile transmission line as part of the PSE Energize Eastside Project (Project). Approximately 4 miles of transmission line upgrade are proposed within Renton city limits. This Technical Information Report (TIR) has been prepared in accordance with the City of Renton Surface Water Design Manual (RMC 4-06-030) and by reference the 2016 King County Stormwater Design Manual (Stormwater Manual). The information provided within is based upon PSE Engineering Design Revision N. The TIR is included with the Civil Construction Permit Application. A project overview and summary of the existing and proposed conditions, assessment of the minimum requirements, and the proposed stormwater management plan are provided in the following sections. The TIR Worksheet is provided in Figure 1-1. 1.0 Project Overview 1.1 Project Description PSE proposes to construct a new 230 kV to 115 kV substation (Richards Creek Substation in Bellevue) and to upgrade approximately 16 miles of existing transmission lines located within an approximately 100-foot wide regional utility corridor to accommodate a 115kV to 230 kV upgrade. The Project will improve reliability and supply the needed electrical capacity for anticipated growth and development in Seattle’s Eastside communities, including the City. For the purposes of this report the “Corridor” is limited to the segment of the proposed Project within the City. The corridor runs from the northern City boundary, south of SE 95th Way, to the existing Talbot Hill Substation in the vicinity of Beacon Way S, a distance of approximately 4 miles. Refer to Figure 1-2 and Figure 1-3 for the site location. The Corridor is generally limited to the area within the boundaries of an approximately 100-foot wide regional utility corridor, except between the Talbot Hill substation and Shadow Hawk neighborhood where the study area was widened to capture additional area based on refined design parameters. The Project corridor is primarily located in the Cedar-Sammamish Watershed (Water Resource Inventory Area (WRIA) 8)). Within WRIA 8 the Project area lies within three drainage basins. The north end of the study area is within the May Creek basin, the middle portion is within the East Lake Washington basin, and the southern portion is in the Lower Cedar River drainage basin. No wetlands or streams were identified in the East Lake Washington basin (The Watershed Company 2016). At the southern end of the Corridor, near the Talbot Hill Substation, is located in the Black River basin of the Duwamish-Green Watershed (WRIA 9). The Project corridor is located in Sections 4, 9, 16, 20, and 21, Township 23N, Range 05E. Technical Information Report PSE Energize Eastside – Renton Segment 2 | December 29, 2020 The proposed improvements will include removal of approximately 144 utility poles, installation of approximately 42 new utility poles, and stringing of transmission wires at 11 proposed stringing sites. Although the Corridor is approximately 4 miles long and 100 feet wide, the areas where there will be new impervious surface and land disturbing activity will be limited to isolated work areas associated with each utility pole removal or installation areas. Figure 1-2 in conjunction with Figure 1-3 provides the general location of the Project area, identifying all roads that border the Project area and all significant geographic features as well as critical areas. Figure 1-1 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Land Use (e.g., Subdivision / Short Subd.) Building (e.g., M/F / Commercial / SFR) Grading Right-of-Way Use Other _______________________ DFW HPA COE 404 DOE Dam Safety FEMA Floodplain COE Wetlands Other ________ Shoreline Management Structural Rockery/Vault/_____ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review(check one): Date (include revision dates): Date of Final: Full Targeted Simplified Large Project Directed ____________________________________ __________________ Plan Type (checkone): Date (include revision dates): Date of Final: Full Modified Simplified ____________________________________ __________________ Ryan Wieder PSE Energize Eastside - Renton Segment Corey Scrima 23N 05E 4, 9, 16, 20, 21 Approximately 12738 NE 24th St to Talbot Hill Substation, Beacon Way S, Renton, WA POWER Engineers, Inc. 208-288-6303 (425) 999-2244 PO Box 97034, EST03W Bellevue, WA 98009 FIGURE 1-1. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/Stream ________________________ Lake ______________________________ Wetlands ____________________________ Closed Depression ____________________ Floodplain ___________________________ Other _______________________________ _______________________________ Steep Slope __________________________ Erosion Hazard _______________________ Landslide Hazard ______________________ Coal Mine Hazard ______________________ Seismic Hazard _______________________ Habitat Protection ______________________ _____________________________________ None None May Creek, East Lake Washington, Lower Cedar River, Black River 2017 Renton Surface Water Design Manual May Creek, Lower Cedar River Wellhead protection areas Wetlands surrounding May Creek and the Lower Cedar River FIGURE 1-1. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________ High Groundwater Table (within 5 feet) Other ________________________________ Sole Source Aquifer Seeps/Springs Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core 2 – Offsite Analysis_________________ Sensitive/Critical Areas__________________ SEPA________________________________ LID Infeasibility________________________ Other________________________________ _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet)Standard: _______________________________ or Exemption Number: ____________ On-site BMPs: _______________________________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Drainage to May Creek, East Lake, and Lower Cedar River 7 locations N/A Flow control exemption and infiltration N/A AmC - Arents, Alderwood material 6 to 15 percent An - Arents, Everett material AkF - Alderwood and Kitsap soils 25 to 70 percent Low 0 to 5 percent Low TBD FIGURE 1-1. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet)Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bogor Exemption No. _______________________ Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control(commercial / industrial land use)Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: N/A N/A N/A FIGURE 1-1. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Collection Dewatering Control Dust Control Flow Control Control Pollutants Protect Existing and Proposed BMPs/Facilities Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize exposed surfaces Remove and restore Temporary ESC Facilities Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary Flag limits of sensitive areas and open space preservation areas Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility On-site BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ Vegetated Flowpath Wetpool Filtration Oil Control Spill Control On-site BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Covenant Tract Other ____________________________ Cast in Place Vault Retaining Wall Rockery > 4′ High Structural on Steep Slope Other _______________________________ FIGURE 1-1. TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed wereincorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date Technical Information Report PSE Energize Eastside – Renton Segment 10 | December 29, 2020 1.2 Purpose This TIR facilitates the permit coordination and approval process related to the storm drainage elements of the Project by documenting the design of the permanent stormwater management plan. The information provided within is based on the PSE Engineering Design Revision N. 1.3 Existing Site Conditions When the corridor was originally constructed in the late 1920s and early 1930s, the entire corridor was cleared. Construction activities resulted in a compacted subsurface in areas where the utility poles were installed. Since that time, the limits of the corridor have been continually maintained by PSE through easement rights. Using existing access routes/paths, utility poles have been replaced and vegetation has been managed. To do so, vehicles and equipment (such as cranes) have been using the corridor. Over time, development has occurred adjacent to and within the corridor, including residential development, roads, parking lots, commercial development, and the establishment of trails (using overgrown access routes). The Talbot Hill area is utilized by an extensive number of co-located critical utilities, which include power substations (owned PSE and Bonneville Power Administration), watermain transmission lines (owned by Seattle Public Utilities), natural gas lines (owned by Olympic Pipeline), and fiber optic communication lines. Most of the developed portions of the Corridor containing vegetation in residential, commercial, and industrial areas can be generally described as maintained yards or landscaped parcels. On parcels that have not been developed as commercial or residential property, vegetated areas are often dominated by invasive plants including Himalayan blackberry and reed canarygrass. Forested patches are limited to topographically low regions near the Cedar River and Honey Dew Creek. 1.4 Existing Soil Conditions According to the Natural Resources Conservation Service soils map for King County, the soils in the corridor are predominantly gravelly, sandy loam. The soils map is shown in Figure 1-4. 1.5 Proposed Site Conditions The proposed site and drainage conditions will result in only minor permanent changes from the existing conditions. This is due to the small footprint required for the proposed utility poles and through construction methods that are intended to minimize impacts to the site. The proposed work elements and the impacts to the site are described below. The Corridor falls within seven threshold discharge areas (TDAs), which are used for assessing stormwater requirements and sizing stormwater facilities. The TDAs and their respective drainage basins are summarized in Table 1. TDA delineations are illustrated on Figure 1-2, subsequent areas were determined based on grade breaks and right-of- way for the Project area. According to definitions provided in the Renton SWDM, all 42 Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 11 proposed poles are considered replaced non pollution generating impervious surfaces, since they are replacing existing structures at new locations without changing the pollution generating characteristics of original structures. Pole removal sites which are not being “replaced” are deemed “new pervious surface” and are in summation, less than ¾ acres. Table 1. TDA and Drainage Basin TDA Drainage Basin1 Disturbed Land Area2 (SF) Replaced Impervious Area (SF) 1 May Creek 40,000 158 2 May Creek via Honey Creek 52,500 237 3 East Lake Washington 12,500 21 4 East Lake Washington 22,500 42 5 Lower Cedar River 35,000 107 6 Lower Cedar River 32,500 93 7 Lower Cedar River 95,000 611 Project Total = 290,000 1,269 1 Drainage Basin per the City of Renton Basin Locations Map (10/16/2009) 2 Disturbed Land Area includes both permanent improvements and areas that will be temporarily disturbed during construction. Land disturbing activity and impervious areas were calculated based on an assumed work area disturbance specific to the proposed work. Type of utility pole and its geometry were taken into consideration when assuming land disturbance. The pole type and disturbance area for each proposed work type is shown in Table 2. Table 2. Land Disturbance and Impervious Area by Proposed Work Proposed Work Land Disturbance Area (SF) per Installation Impervious Area per pole (SF) Installation of Type C-1 pole: 5,000 7a Installation of Type C-2 pole: 5,000 36b Installation of Type C-16 pole: 2,500 7a Installation of Type C-17 pole: 5,000 36b Installation of Type C-18 pole: 5,000 36b Installation of Type C-19 pole: 5,000 36b Stringing Site 7,500 N/A a Area based on 3-foot-diameter, direct embed-single utility pole. b Area based on 6 by 6 foot, foundation-single pole. Technical Information Report PSE Energize Eastside – Renton Segment 12 | December 29, 2020 This page intentionally left blank. MAP CREATED BY: Date: 1/5/2018Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Landuse_CUP\Renton\Version_N\PSE_Renton_Index.mxdTopo Basemap - ESRI Online,Transmission Line - PSE ST169 ST900 §¨¦405 Renton Renton Newcastle KingCounty I0 0.25 0.5 Mile RENTON CLEARING AND GRADING PLAN INDEX SOURCES: APPLICANT: Brad StrauchPuget Sound EnergyP.O. Box 97034, Bellevue WA 98009-9734(425) 456 - 2556 Watershed Boundary: (North) - E. Lake Washington via SR900 (South) - E. Lake Washington via NE 7th St Drainage Basin Boundary: (North) - May Creek (South) - May Creek via Honey Creek Watershed Boundary: (North) - Lower Cedar River (South) - Black River TDA AND DRAINAGE BASIN MAP FIGURE 1-2 LEGEND: TDA BOUNDARY DRAINAGE BASIN BOUNDARY WATERSHED BOUNDARY TDA #1 4.5 Ac TDA #2 7.8 Ac TDA #3 4.0 Ac TDA #4 9.0 Ac TDA #5 8.3 Ac TDA #6 5.5 Ac TDA #7 28.4 Ac Watershed Boundary: (West) - East Lake Washington (East and South) - Lower Cedar River Watershed Boundary: (West) - East Lake Washington (East) - Lower Cedar River Watershed Boundary: (North) - May Creek (South) - East Lake Washington Talbot SubstationSR900NE 4th StUnion Ave NE Monroe Ave NE Edmonds Ave NE Technical Information Report PSE Energize Eastside – Renton Segment 14 | December 29, 2020 This page intentionally left blank. §¨405 Renton Newcastle §¨90 ST169 ST900City of RentonKing CountyNE PARK DRN 3RD STNE 4TH STN 4TH STNE 3RD STHOU S E R W A Y N Py An Ur EvC AgD AkF EvB PITSUr EvC AgC EvD AmB An W AgC AgC Py Ma Sm Ur AgC InD EvD AgD Rh AgC EvC EvC AmC Ur AmC AmC PITS BeDBeD Pc AkF EvC Ur InC Pc InC AgC AgC AgC An Rh AgC AmC AkF Py AgD AmC RdC EvC RdC RdE AmC AgD AkF AkF EvB AmC AgD Date: 4/27/2020Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\Landuse_CUP\SOILS\PSE_Renton_SOIL.mxdProject Corridor I BASED ON PSE ENGINEERING DESIGN REVISION N MAP EXTENT RENTON SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.I0 600 1,200 Feet 1 inch = 1,200 feet §¨¦405 Transmission Line - Proposed City Jurisdiction Boundary Hydric Soil No Data Excessively drained Somewhat excessively drained Well drained Moderately well drained Very poorly drained Soil Legend AgC - Alderwood gravelly sandy loam, 8 to 15 percent slopes AgD - Alderwood gravelly sandy loam, 15 to 30 percent slopes AkF - Alderwood and Kitsap soils, very steep AmB - Arents, Alderwood material, 0 to 6 percent slopes AmC - Arents, Alderwood material, 6 to 15 percent slopes An -Arents, Everett material BeC - Beausite gravelly sandy loam, 6 to 15 percent slopes EvB - Everett very gravelly sandy loam, 0 to 8 percent slopes EvC - Everett very gravelly sandy loam, 8 to 15 percent slopes EvD - Everett very gravelly sandy loam, 15 to 30 percent slopes InC - Indianola loamy sand, 5 to 15 percent slopes InD - Indianola loamy sand, 15 to 30 percent slopes Ma - Mixed alluvial land No - Norma sandy loam Pc - Pilchuck loamy fine sand PITS - Pits Py - Puyallup fine sandy loam RdC - Ragnar-Indianola association, sloping RdE - Ragnar- Indianola association, moderately steep Rh - Riverwash Sm - Shalcar muck Ur - Urban land W - Water FIGURE 1-3. EXISITING SOIL CONDITIONS Technical Information Report PSE Energize Eastside – Renton Segment 16 | December 29, 2020 This page intentionally left blank. Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 17 2.0 Conditions and Requirements Summary The stormwater design is based on the following permit conditions, design standards and requirements, and guidance manuals. 2.1 Requirements Summary Permit Conditions Comply with the City of Renton Municipal Code and pre-approved City policies and by reference the 2016 King County Surface Water Design Manual (KCSWDM). Design Standards, Requirements, and Guidance Manual ● 2017 City of Renton Surface Water Design Manual (City of Renton 2017) ● 2016 King County Surface Water Design Manual (KCSWDM) (King County 2016a). ● Low Impact Development Technical Guidance Manual for Puget Sound (LID 2012). 2.2 Stormwater Requirements Assessment The stormwater requirements for the project were determined based on the methodology provided in Chapter 1 of the 2017 City of Renton Surface Water Design Manual (Renton SWDM). The type of review and applicability of the core and special requirements were determined by evaluating the amount of new and replaced impervious surfaces, land disturbing activity, and total amount of new impervious surfaces in a hydraulically connected subbasin. The type of drainage review is identified by the criteria illustrated in Figure 2-1. This project will create less than 2,000 square feet (1,269 square feet, see Table 1) of new plus replaced impervious surface, and creates less than 50 acres of new impervious surface within a hydraulically connected subbasin. However, it will require greater than 7,000 square feet of land disturbing activity and therefore will be subject to a Full Drainage Review. As a result, all nine Core Requirements and all five Special Requirements are required to be evaluated for each Project TDA area. Per the Renton Surface Water Design Manual, land disturbing activity means any activity that results in a change in the existing soil cover, both vegetative and non-vegetative, or the existing soil topography. Land disturbing activities include, but are not limited to demolition, construction, clearing, grading, filling, excavation, and compaction. Land disturbing activity does not include tilling conducted as part of agricultural practices, landscape maintenance, or gardening. The Core and Special Requirements that apply to this project and justifications for requirements that are not applicable to the project are discussed in the remainder of this section. Technical Information Report PSE Energize Eastside – Renton Segment 18 | December 29, 2020 Figure 2-1. Drainage Review Flow Chart Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 19 Table 3. Summary of Core Requirements Core Requirement Project Exemption Justification #1: Discharge at the Natural Location No The project will comply with the Discharge Requirements described in the Renton SWDM #2: Offsite Analysis Yes 1. The project does not change the rate, volume, duration, or location of discharges to and from the project site (e.g., where existing impervious surface is replaced with other impervious surface having similar runoff-generating characteristics, or where pipe/ditch modifications do not change existing discharge characteristics).1 #3: Flow Control Facilities Yes 1. The project will create less than 5,000 square feet of new plus replaced impervious surface AND 2. Less than ¾ acres of new pervious surface will be added Shown in area calculations in Section 1.5 of this report1 #4: Conveyance System No The project will comply with the Conveyance Requirements for Existing Systems as described in the Renton SWDM #5: Construction Stormwater Pollution Prevention No The project will comply with the Construction Stormwater Pollution Prevention Requirements as described in the Renton SWDM #6: Maintenance and Operations No No exemption is offered for this Core Requirement; however, drainage facilities within the project are maintained by the City of Renton as described in the Renton SWDM #7: Financial Guarantees and Liability No The project will comply with Financial Guarantees and Liability as described in the Renton SWDM #8: Water Quality Facilities Yes 1. The project will create less than 5,000 square feet of new plus replaced PGIS that is not fully dispersed AND 2. The project will create less than ¾ acres of new PGPS that is not fully dispersed Shown in area calculations in Section 1.5 of this report1 #9: On-Site BMPs No The project will provide on-site BMPs as described in the Renton SWDM 1 Exemption justification per 2017 City of Renton SWDM, Section 1.2 Core Requirement Core Requirement #1 – Discharge at the Natural Location Core Requirement #1 will be satisfied by maintaining the existing drainage patterns of the site and discharging to existing downstream drainage systems. The proposed improvements will be limited to transmission pole installations with footprints that range between approximately 7 and 36 square feet. For utility poles installed in vegetated areas, surrounding areas will be designed to allow stormwater runoff to sheet flow in a dispersed manner. Surface restoration around utility poles installed in paved areas will Technical Information Report PSE Energize Eastside – Renton Segment 20 | December 29, 2020 be graded to drain to existing drainage systems, matching existing drainage patterns in the vicinity. Stormwater generated from project activities will not create significant adverse impact to downhill properties or drainage facilities as it is expected to fully infiltrate or naturally disperse before reaching such locations. Since the proposed project is not located within a Landslide Hazard Drainage Area, as defined in the Renton SWDM, a tight line system is not required. However, there are utility pole locations adjacent to landslide, steep slope, and erosion hazard areas. Project work and operation will not create adverse impacts to downhill properties or drainage systems near these areas through the use of on-site Best Management Practices (BMPs). A full list of the proposed, on-site BMPs has been included in the Construction Stormwater Pollution Prevention Plan (CSWPP) developed for this project, see Appendix A. Core Requirement #2 – Offsite Analysis The project is exempt from Core Requirement #2 as described in Table 3. Core Requirement #3 – Flow Control The Project is exempt from Core Requirement #3 as described in Table 3. Core Requirement #4 – Conveyance System No pipe conveyance, ditch, or culvert systems will be constructed or modified for this project, thus Core Requirement #4 is applicable per Conveyance Requirements for Existing Systems. The proposed project will not change in flow characteristics (e.g., peak flows or volume of flows) experienced by existing onsite conveyance systems. The project will result in only minor changes from existing conditions, generating the same, or less, stormwater runoff to the existing conveyance system. Core Requirement #5 – Erosion and Sediment Control Core Requirement #5 will be satisfied by the Erosion and Sediment Control (ESC) Plan and CSWPP, developed in accordance with the City of Renton stormwater requirements. See Appendix A for the CSWPP which contains ESC Plans. Core Requirement #6 – Maintenance and Operations Existing drainage facilities within the Project area are not expected to require additional maintenance as the Project will result in only minor changes to existing conditions, generating the same, if not less, stormwater runoff to the existing drainage facilities. However, per Core Requirement #6, because existing drainage facilities within the Project area are located in dedicated City Right-of-Way (ROW), maintenance will be conducted by the City of Renton as required. Core Requirement #7 – Financial Guarantees and Liability Core Requirement #7 will be satisfied by providing the financial guarantee and liability information as required by the City of Renton. Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 21 Core Requirement #8 – Water Quality The Project is exempt from Core Requirement #8 as described in Table 3. Core Requirement #9 – On-Site BMPs The Project involves greater than 7,000 square feet of land disturbing activity as discussed in Section 1.5. On-site BMPs will mitigate the impacts of storm and surface water runoff generated by the project per Core Requirement #9 during construction. On- site BMPs are included in the CSWPPP (Appendix A). Special Requirement #1 – Other Adopted Requirements Special Requirement #1 does not apply to the Project as the area does not involve any of the Other Adopted Area-Specific Requirements listed in Section 1.3.1 of the Renton SWDM. Special Requirement #2 – Flood Hazard Area Delineation Special Requirement #2 does not apply to the Project as it is not located within a mapped flood hazard area, as defined by City of Renton Critical Area maps. Special Requirement #3 – Flood Protection Facilities Special Requirement #3 does not apply to the Project since the proposed improvements do not rely on an existing or proposed flood protection facility (such as a levee or revetment) for protection against hazards posed by erosion or inundation. Special Requirement #4 – Source Control Special Requirement #4 does not apply to the Project since the proposed improvements do not require a commercial building or commercial site development permit. Special Requirement #5 – Oil Control Special Requirement #5 does not apply to the Project because it will not be classified as a new high-use site. Where utility poles will be installed on existing high-use sites there are already oil control facilities in place. Additionally, the proposed improvements do not warrant an increase in oil protection. Special Requirement #6 – Aquifer Protection Area Special Requirement #6 is applicable to the Project since is located within Aquifer Protection Area Zone 1 per the Groundwater Protection Areas Map (see Appendix C). The Special Requirement will be satisfied by not constructing open stormwater facilities (i.e., flow control or water quality ponds, stormwater wetlands, or infiltration facilities), On-site BMPs that rely on infiltration (except dispersion of non-pollution generating area), or open conveyance systems. Technical Information Report PSE Energize Eastside – Renton Segment 22 | December 29, 2020 3.0 Offsite Analysis 3.1 Level 1 Downstream Analysis As described in Section 2.2, the Project qualifies for an exemption from conducting an offsite analysis. The Project entails replacement by relocation of impervious surfaces to nearby locations, with similar topography and soil characteristics. Therefore, the Project does not change the rate, volume, duration, or location of discharges to and from the Project site. 4.0 Flow Control, Low Impact Development (LID), and Water Quality Analysis and Design 4.1 Existing Site Hydrology The stormwater runoff from the developed portions of the Corridor are managed through a combination of local parking lot/private property drainage system and roadway drainage systems. The existing systems are comprised of a variety of system that include closed pipe conveyance systems, ditches, and culverts. The stormwater runoff from the undeveloped portions of the Corridor is very limited, relying on occasional ditch and culvert systems that ultimately drain to the adjacent roadway drainage systems, disperse into natural areas, or directly to a downstream water body. 4.2 Developed Site Hydrology The proposed site and drainage hydrology will result in only minor permanent changes from the existing hydrology. Minimal impervious area will be added to the Project as a result of the proposed utility poles, see Table 1 for impervious areas for each TDA. The Project will largely maintain existing site hydrology and no flow control or conveyance facilities are proposed. 4.3 Performance Standards Area-Specific Flow Control Facility Standard The Project is exempt from flow control standards based upon the criteria in the formal Basic Exemption, when analyzed on the TDA level. The proposed improvements in each of the seven TDAs will create less than 5,000 square feet of new plus replaced impervious surfaces and less than ¾ acres (32,670 square feet) of new pervious surface, as shown in Table 1. On-Site BMP Requirements Per Core Requirement 9, on-site BMPs must be included in the Project design. Projects that trigger Core Requirement #9 by disturbing 7,000 square feet or more of land, but where new plus replaced impervious is less than 2,000 square feet, may consider basic dispersion as an equal choice for treating the target impervious surfaces alongside full Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 23 infiltration, limited infiltration, bioretention, and permeable pavement BMPs. For this Project, sheet flow dispersion BMPs will be used to meet the on-site BMP requirement as per the CSWPPP (Appendix A) for poles with foundations. Water Quality Standard The Project is exempt from water quality standards based upon the criteria in the formal Surface Area Exemption. The proposed improvements in all seven TDAs will create less than 5,000 square feet of new plus replaced pollution generating impervious surfaces and less than ¾-acre (32,670 square feet) of new pollution generating pervious surface, as illustrated in Table 1. Oil Control Standard The Project is exempt from oil control standards since it is not classified as a new high- use site. Where utility poles will be installed on existing high-use sites there are already oil control facilities in place. Additionally, the proposed improvements do not warrant an increase requirement for oil protection. 4.4 Flow Control System BMPs used for flow control and their application locations are included in the CSWPPP in Appendix A. 4.5 Water Quality System No water quality systems are proposed as part of the Project since the Project is exempt from water quality standards. 5.0 Conveyance System Analysis and Design The Project is exempt from this section since no conveyance systems, including pipes, ditches, or culverts, will be constructed or modified as part of this Project. 6.0 Special Reports and Studies As the Project area includes and lies adjacent to steep slopes, wetlands, and erosion hazard zones, a Critical Areas Report was prepared in January 2018 addressing the potential impacts associated with the Project. The Critical Areas Report is included in Appendix B. 7.0 Other Permits The following permits are required from the City for the Project Conditional Use Permit Shoreline Exemption Civil Construction Permit Technical Information Report PSE Energize Eastside – Renton Segment 24 | December 29, 2020 Right – of – Way Permit The Project will require additional permits from other jurisdictions including the cities of Bellevue, Newcastle, and Redmond. 8.0 CSWPP Analysis and Design The project will follow CSWPP standards as outlined in Section 1.2.5 of the 2017 Renton Surface Water Design Manual. The full CSWPPP can be referenced in Appendix A of this report. 8.1 Erosion Sediment Control (ESC) Plan and Analysis Design ESC measures are provided on a pole by pole basis, depending on existing site conditions. Site specific details for ESC and BMPs that will be used during construction are included in Appendix A. In addition to the site specific plans, the following general BMPs for ESC will be used in accordance with Section 1.2.5 of the 2017 Renton Surface Water Design Manual. 1. Mark clearing limits – Construction limits will be clearly marked where necessary before construction begins to protect adjacent properties and reduce the volume of soil exposed to construction. Existing vegetation will be maintained to the greatest extent possible in situations where pole access is through vegetated areas. 2. Cover measures – Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas 3. Perimeter protection – No cut and fill slopes are associated with this Project; therefore, no BMPs are proposed for this element. 4. Traffic area stabilization – The majority of access roads for this Project are paved, gravel, or established roads. Generally, temporary access roads are short and vegetated, posing little dust or track-out risk. Wetland matting will further minimize track-out from temporary accesses if conditions require. 5. Sediment retention – The majority of access to poles is through paved or densely vegetated areas that pose little risk of sediment discharge. Poles located in close proximity to critical areas or existing stormwater conveyance channels will use straw wattles and silt fence to contain disturbed soils. 6. Surface water collection – No increase in stormwater runoff volumes is expected due to the proposed work and surface water conveyance structures exist in proposed work locations; therefore, no additional BMPs for surface water collection are proposed. Sheet flow dispersion will be used for poles with impervious foundations. 7. Dewatering control – Dewatering is not anticipated, but if groundwater is encountered it will be collected by a vactor trick and disposed at an approved off- site location. Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | 25 8. Dust control – The Project is located west of the Cascade Mountain Crest; therefore, soils may remain exposed and unworked for no more than seven days during the dry season (May 1 – September 30) or two days during the wet season (October 1 – April 30). Between these times, exposed soils will be temporarily protected with mulching or plastic covering. Dust control measures may include watering, temporary gravel construction entrances, and haul truck covers (as needed). 9. Flow control – Flow control requirements are not triggered by the proposed pole replacement work per the City of Renton Surface Water Design Manual. 10. Control pollutants – All pollutants that occur on site shall be handled and disposed of in a manner that does not result in stormwater contamination. Cover, containment and protection from vandals shall be provided for all chemicals, liquid products, petroleum products and non-inert wastes. 11. Protect existing and proposed flow control BMPs – Existing flow control BMPs are not expected to receive construction stormwater. There are no proposed flow controls BMPs per Element 9 above. 12. Maintain protective BMPs – All temporary and permanent ESC BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. 13. Manage the project – Coordination and timing of site development activities relative to ESC concerns, seasonal work limitations, timely inspection, maintenance and update of protective measures will be managed to reflect changing site conditions. Proposed Project areas with particularly high susceptibility to erosion because of slopes or soils, as well as areas to be protected for existing and proposed on-site BMPs, can be found in Figure 1-3, as well as the TESC plans in the CSWPPP, included in Appendix A 8.2 Stormwater Pollution Prevention and Spill Control Plan (SWPPS) Potential pollution generating activities for this Project are limited to concrete application, sawcutting and surfacing pollution prevention, material delivery, handling and storage, maintenance of BMPs, and management of the Project. The following BMPs, in accordance with SWPPS measures from the King County SWDM, will be utilized in addition to those previously mentioned. BMP C.2.1.6 Sheet Flow Dispersion (Ecology BMP T5.12) BMP D.2.2.1 Concrete Handling (Ecology BMP C151) BMP D.2.2.4 Material Delivery, Storage and Containment (Ecology BMP C153) BMP D.2.2.2 Concrete Washout Area (Ecology BMP C154) BMP D.2.1.5.3 Storm Drain Inlet Protection (Ecology BMP C220) BMP D.2.1.3.1 Silt Fence (Ecology BMP C233) Technical Information Report PSE Energize Eastside – Renton Segment 26 | December 29, 2020 BMP D.2.1.2.5 Straw Wattles (Ecology BMP C235) BMP D.1.1 Scheduling (Ecology BMP C162) BMP D.2.3.1 Certified Erosion and Sediment Control Lead (Ecology BMP C160) The Project is not anticipated to discharge to 303(d) listed waterbodies in Category 5 (listed for turbidity, fine sediment, phosphorus, or pH). However, the Project is in proximity to 303(d) waterbodies: May Creek (listed for temperature) and the Cedar River (listed for temperature, dissolved oxygen, and pH). Any Project stormwater generated is not anticipated to discharge to these waterbodies as the nature of work is localized to pole areas, with all at-risk stormwater expected to infiltrate prior to possible discharge. A more detailed discussion of receiving waters can be found in the CSWPPP included in Appendix A. 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant Bond quantities and Declaration of Covenant can be found in Appendices D and E, respectively. A Facility Summary is not required, as no facilities are being constructed for the Project. 10.0 Operations and Maintenance Manual Operations and maintenance is not required, as stated in core element #6 as no facilities are being constructed for the Project. 11.0 References 2017 City of Renton Surface Water Design Manual 2016 King County Surface Water Design Manual Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | Appendix A – Construction Stormwater Pollution Prevention Plan and ESC Plans Construction Stormwater General Permit Stormwater Pollution Prevention Plan (SWPPP) for Energize Eastside – Renton Segment – Transmission Line Rebuild Project Prepared for: The Washington State Department of Ecology Northwest Regional Office Permittee / Owner Operator / Contractor Puget Sound Energy TBD From pole 4/1 near 12738 NE 24th Street, Renton, WA 98056 To pole 0/1 near Talbot Hill Substation, Beacon Way S, Renton, WA 98055 Contacts Role Name Organization Contact Phone Number SWPPP Preparer Nik Anderson HDR 425-468-1541 CESCL TBD TBD TBD Construction Manager Dennis Griffith PSE 425-864-0568 SWPPP Preparation Date December 29, 2020 Anticipated Project Construction Dates Start Date End Date TBD TBD Table of Contents 1 Project Information ........................................................................................................... 1 2 Construction Stormwater Best Management Practices (BMPs) .......................................... 2 3 Pollution Prevention Team ................................................................................................ 8 4 Monitoring and Sampling Requirements............................................................................ 8 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies........................ 10 6 Reporting and Record Keeping ....................................................................................... 11 List of Appendices A. Temporary Erosion and Sediment Control (TESC) Plans ....................................................... B. BMP Details .......................................................................................................................... 1 Project Information Project/Site Name: Energize Eastside – Renton Segment – Transmission Line Rebuild Project Street/Location: Approximately 12738 NE 24th Street to Talbot Hill Substation, Beacon Way S City: Renton State: WA Zip Code: 98056 Receiving waterbody: The project corridor crosses the Cedar River, May Creek and is in close proximity to Lake Washington. 1.1 Existing Conditions Total acreage (including support activities such as off-site equipment staging yards, material storage areas, borrow areas). Total acreage: 1,940,000 Disturbed acreage: 14.5 acres Existing structures: The project includes 41 new poles, some of which will require a new concrete foundation. All of the new poles replace existing structures in the transmission corridor. Landscape topography: In general, the topography of the alignment consists of rolling hills, crossing May Creek valley and eventually the Cedar River Valley. The majority of the work is in residential neighborhoods and commercial areas. Drainage patterns: Stormwater runoff generated by roadways enter conveyance ditches that are conveyed directly to local streams and tributaries. Existing vegetation: Existing vegetation on and adjacent to the right-of-way includes coniferous and deciduous trees, shrubs, herbaceous plants and maintained residential lawn. Critical Areas: Critical areas within the project vicinity include wetlands, streams, and steep slopes There are water bodies near the project site that are listed under 303(d) for temperature, pH and dissolved oxygen in the vicinity of the project. Details for each can be found in section 5 below. Project stormwater is not anticipated to discharge to these water bodies. 1.2 Proposed Construction Activities The proposed project consists of removal of approximately 144 existing poles, installation of approximately 41 new poles, and stringing new transmission cables along a 4-mile section of the Energize Eastside Transmission line corridor. The project spans from pole 4/1 near 12738 NE 24th Street to pole 0/1 near Talbot Hill Substation, Beacon Way S. The majority of the transmission poles will be replaced with similar structures in close proximity to the existing poles. Holes will be excavated with truck mounted augers, vactoring, or hand- excavation. Minor improvements may need to be made to facilitate equipment access to certain poles as well as BMP installation. In general, the disturbance at each structure is minor and the majority of stormwater is infiltrated. Where poles are located in close proximity to existing drainage ditches or other stormwater infrastructure, BMPs will be installed to prevent the discharge of sediment. Contaminated Site Information: No known contaminated soils or groundwater occur within the project corridor. If contaminated soils or groundwater are encountered, the contractor will immediately notify the Environmental lead and PSE. 2 Construction Stormwater Best Management Practices (BMPs) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e., hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits To protect adjacent properties and reduce the volume of soil exposed to construction, construction limits will be clearly marked where necessary before construction begins. In situations where pole access is through vegetated areas, existing vegetation will be maintained to the greatest extent possible. Many of the remaining poles can be replaced from the roadway, reducing the disturbed area to approximately the footprint of the pole. List and describe BMPs: • BMP C101 Preserving Natural Vegetation • BMP C103 High Visibility Plastic Fence1 Installation Schedules: BMPs will be implemented prior to any access improvements or pole replacement activities. At the first indication that existing BMPs are inadequate, the Environmental Lead will promptly recommend the implementation of alternative BMPs listed in Appendix D of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or in Volume 2, Section 4 of the Stormwater Management Manual for Western Washington (SWMMWW) (Washington State Department of Ecology, 2012), where applicable. Inspection and Maintenance plan: Inspect once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project influence as required by the Construction Stormwater General Permit (CSWGP). Repair or replace any damaged or ineffective BMPs immediately. 2.1.2 Element 2: Establish Construction Access The majority of the poles in the alignment can be directly accessed from a paved roadways, gravel driveways or established access roads. In general, temporary access roads are short and vegetated, so they do not pose a high dust or track-out risk. Wetland matting will further minimize track-out from temporary accesses, if current conditions require them. List and describe BMPs: • BMP C105 Stabilized Construction Entrance2 Installation Schedules: At the first indication that conditions are deteriorating, the Environmental Lead will promptly recommend the implementation of BMPs listed in Appendix D of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or Volume 2, Section 4 of the SWMMWW (Washington State Department of Ecology, 2012), where applicable. Inspection and Maintenance plan: Inspect once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project influence as required by the CSWGP. Repair or replace any damaged or ineffective BMPs immediately. 1 D.2.1.1.1 Pastic or Metal Fence, 2017 City of Renton Surface Water Design Manual 2 D.2.1.4.1 Stabilized Construction Entrance, 2017 City of Renton Surface Water Design Manual 2.1.3 Element 3: Control Flow Rates The proposed pole replacement work does not trigger the flow control requirements of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or the SWMMWW (Washington State Department of Ecology, 2012), and stormwater discharge volumes from the project influence are not expected to increase due to the proposed work. No BMPs are proposed for this element. 2.1.4 Element 4: Install Sediment Controls Access to many poles that is not from a paved area is through densely vegetated areas that pose little risk of sediment discharge. The areas of primary concern are poles that are located in close proximity to critical areas or existing stormwater conveyance channels as well as construction access points, the latter having been previously considered under Element 2. Straw wattles and silt fence will be used to contain any disturbed soils around the base of each pole and to control the perimeter of access roads and work areas. Water from inside the project influence is expected to infiltrate as discussed in Element 3. List and describe BMPs: • BMP C233 Silt Fence3 • BMP C235 Straw Wattles4 Installation Schedules: BMPs will be implemented prior to any access improvements or pole replacement activities. At the first indication that existing BMPs are inadequate, the Environmental Lead will promptly recommend the implementation of alternative BMPs listed in Appendix D of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or Volume 2, Section 4 of the SWMMWW (Washington State Department of Ecology, 2012). Inspection and Maintenance plan: Inspect once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project influence as required by the CSWGP. Repair or replace any damaged or ineffective BMPs immediately. 2.1.5 Element 5: Stabilize Soils The project is located West of the Cascade Mountain Crest; therefore, soils may remain exposed and unworked for no more than seven days during the dry season (May 1 – September 30) or two days during the wet season (October 1 – April 30). Between these times, exposed soils will be temporarily protected with mulching or plastic covering. Upon completion of work in each area, exposed soils will be permanently stabilized with seeding or gravel. 3 D.2.1.3.1 Silt Fence, 2017 City of Renton Surface Water Design Manual 4 D.2.1.2.5 Straw Wattles, 2017 City of Renton Surface Water Design Manual Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. List and describe BMPs: • BMP C120 Temporary and Permanent Seeding5 • BMP C121 Mulching6 • BMP C123 Plastic Covering7 • BMP C140 Dust Control8 • Other BMP Gravel Installation Schedules: BMPs will be implemented prior to any access improvements or pole replacement activities. At the first indication that existing BMPs are inadequate, the Environmental Lead will promptly recommend the implementation of alternative BMPs listed in Appendix D of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or Volume 2, Section 4 of the SWMMWW (Washington State Department of Ecology, 2012). Inspection and Maintenance plan: Inspect once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project influence as required by the CSWGP. Repair or replace any damaged or ineffective BMPs immediately. 2.1.6 Element 6: Protect Slopes No cut and fill slopes are associated with this project; therefore, no BMPs are proposed for this element. 2.1.7 Element 7: Protect Drain Inlets There are a number of drain inlets in the project influence, none of which are expected to receive construction stormwater. In the event site conditions change and pose a risk to drain inlets, the following is proposed: List and describe BMPs: • BMP C220 Storm Drain Inlet Protection9 Installation Schedules: 5 D.2.1.2.6 Temporary and Permanent Seeding, 2017 City of Renton Surface Water Design Manual 6 D.2.1.2.2 Mulching, 2017 City of Renton Surface Water Design Manual 7 D.2.1.2.4 Plastic Covering, 2017 City of Renton Surface Water Design Manual 8 D.2.1.8 Dust Control, 2017 City of Renton Surface Water Design Manual 9 D.2.1.5.3 Storm Drain Inlet Protection, 2017 City of Renton Surface Water Design Manual BMPs will be implemented prior to any access improvements or pole replacement activities. At the first indication that existing BMPs are inadequate, the Environmental Lead will promptly recommend the implementation of alternative BMPs listed in Appendix D of the City of Renton Surface Water Design Manual (December 2016) or Volume 2, Section 4 of the SWMMWW (Washington State Department of Ecology, 2012). Inspection and Maintenance plan: Inspect once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project influence as required by the CSWGP. When working within paved areas, the contractor shall sweep up all track out on the City right-of-way daily to prevent sediment entering the catch basins. Repair or replace any damaged or ineffective BMPs immediately. 2.1.8 Element 8: Stabilize Channels and Outlets All roadway runoff within the project site is conveyed within existing channels. The existing stormwater conveyance system should not experience an increase in stormwater runoff volumes due to the proposed work. Therefore channel and outlet stabilization are not necessary. Stormwater runoff that does not enter the roadway conveyance system sheet flows through vegetated areas. 2.1.9 Element 9: Control Pollutants All pollutants that occur on site shall be handled and disposed of in a manner that does not result in stormwater contamination. Cover, containment and protection from vandals shall be provided for all chemicals, liquid products, petroleum products and non-inert wastes. Contaminated surfaces shall be cleaned immediately. List and describe BMPs: • BMP C151 Concrete Handling10 • BMP C153 Material Delivery, Storage and Containment11 • BMP C154 Concrete Washout Area12 Installation Schedules: BMPs will be implemented prior to any activity that involves a potential pollutant. BMPs will continue to be used for the duration of the activity with which they’re involved. Inspection and Maintenance plan: Inspect for proper storage and containment once every calendar week. Repair or replace any damaged or ineffective BMPs immediately. 10 D.2.2.1 Concrete Handling, 2017 City of Renton Surface Water Design Manual 11 D.2.2.4 Material Delivery, Storage, and Containment, 2017 City of Renton Surface Water Design Manual 12 D.2.2.2 Concrete Washout Area, 2017 City of Renton Surface Water Design Manual 2.1.10 Element 10: Control Dewatering Dewatering is not anticipated, but if groundwater is encountered it will be collected by a vactor truck and disposed of at an approved off-site location. Installation Schedules: BMPs will be implemented in the event groundwater is encountered and needs to be collected. 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Appendix D of the City of Renton Surface Water Design Manual (City of Renton, WA, December 2016) or Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles: • Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. • Proper scheduling and sequencing of project activities will be accounted for to minimize risk of erosion and sediment discharge per BMP C162. • Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Monitoring of the project will be accomplished by a Certified Erosion and Sediment Control Lead (CESCL) as outlined in BMP C16013. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. • Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs There are no LID elements within the project influence. 3 Pollution Prevention Team Table 1 – Team Information Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer TBD TBD Emergency Ecology Contact TBD TBD Emergency Permittee/ Owner Contact TBD TBD Ecology Regional Office Northwest Regional Office 425-649-7000 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 13 D.2.1.12 Manage the Project, 2017 City of Renton Surface Water Design Manual Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map and in accordance with the applicable requirements of the CSWGP. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Turbidity will be sampled with a Turbidity Meter/Turbidimeter for the duration of the project. The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System (ERTS) within 24 hours. • Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: • Turbidity is 25 NTU (or lower). • Transparency is 33 cm (or greater). • Compliance with the water quality limit for turbidity is achieved. o 1 - 5 NTU over background turbidity, if background is less than 50 NTU o 1% - 10% over background turbidity, if background is 50 NTU or greater • The discharge stops or is eliminated. 4.2.2 pH Sampling pH monitoring is required for “Significant concrete work” (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. The proposed poles with concrete foundations will have a total volume well below the 1000 cubic yard threshold; therefore, there is no significant concrete work or use of recycled concrete/engineered soils associated with this project. 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies 5.1 303(d) Listed Waterbodies Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): 1. May Creek (Listed for temperature, otherwise not applicable). 2. Cedar River (Listed for temperature, dissolved oxygen and pH) The south end of the project alignment crosses the Cedar River valley. Work on either side of the river is short in duration, vey localized in nature, set back 700 feet from the river and not expected to generate any discharge. Access to work areas on either side of the river is from established access roads or paved areas with satisfactory ground conditions. Project stormwater is not anticipated to discharge to these waterbodies. The nature of the work is very localized and all at-risk stormwater is expected to infiltrate. 6 Reporting and Record Keeping 6.1 Record Keeping 6.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs 6.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: • CSWGP • Permit Coverage Letter • SWPPP • Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. 6.1.3 Updating the SWPPP The SWPPP will be modified if: • Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. • There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. 6.2 Reporting 6.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting “No Discharge”. The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology’s WQWebDMR System. 6.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 1. Your name and Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Appendix A. Temporary Erosion and Sediment Control (TESC) Plans MAP CREATED BY: V3: 03/02/2021Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC_Index.mxdTopo Basemap - ESRI Online,Transmission Line - PSE ST169 ST900 §¨¦405 Renton Renton Newcastle KingCounty 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 I0 0.25 0.5 Mile RENTON TEMPORARY EROSION ANDSEDIMENT CONTROL (TESC) PLANINDEX SOURCES: APPLICANT:Ryan WiederPuget Sound EnergyP.O. Box 97034, Bellevue WA 98009-9734 (425)999 - 2244 ACREAGE IN RENTON: 44.5 acres §¨¦405 Renton Newcastle 8 8888!(D!(D&-&-4/2 C-16A A1 4/2 C-16B A1 BMP S2 BMPS2 BMPC121d BMPC120c SE 95TH WAY0423059142 33451004453345100450 3345100470 3345100475 7788000140 K i n g C o untyC i t y o f N e w cas t leC i t y o f R entonPath: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I220+00831 4/2 SCT10 EAST 100FT/WEST 100FT STA=221+56.71 HT=88FT ELE=325.36 400 420440 460480 340 360 380 320 300 280 500 520 540560 400 420440 460480 340 360 380 320 300 280 500 520 540560 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 2Date: 8/23/2018 Page 1 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFTKing CountyPole information is provided in the plans as follows: 0/1 Pole Number SCDE90 Engineering Pole Description 110FT Total Length of Pole (includes subsurface length for direct embed poles) STA 572+38 Survey Stationing HT=110FT ELE=63 Pole Height above-ground and Pole Base Elevation above MSL V3 Date: 03/02/2021 §¨¦405 Renton Newcastle88!(D!(D&-&-4/1 C-18A C1 4/1 C-18B C1 #*#*BMPC120c BMPC151g BMPC120c 0423059069 0423059142 3345100450K i n g C o untyC i t y o f R entonPath: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I215+00210+00501 831 4/1 SCDE60 EAST 072FT/WEST 072FT STA=213+1.0 HT=72FT ELE=449.25 400 420440 460480 340 360 380 320 500 520 540560 580 600 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 1MATCHLINE SHEET: 3Date: 8/23/2018 Page 2 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 888888!(D!(D!(D!(D!(D&-&-&-&-&-3/9 C-17A C1 3/9 C-17B C1 3/10 C-2A C1 3/10 C-2B C1 4/1C-18AC1 #*BMPC151 BMPC121d BMPC120c BMPC151g BMPS2 P20 P S E 1 0 0 T H S T N E 2 4 T H S T 0423059002 0423059069 0423059142 0423059282 0423059313 04280000100428000015 0428000020 0428000290 K i n g C o unty C i t y o f R e n t o n Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I210+00501 205+00418 3/10 SCA15 EAST 095FT/WEST 095FT STA=208+1.11 HT=95FT ELE=450.50 400 420 440 460 480 380 500 520 540560 580 600 620 640 660680 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 2MATCHLINE SHEET: 4Date: 8/23/2018 Page 3 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT C120c BMP BMPT5.12 BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8888!(D!(D!(D!(D&-&-&-&-&-3/7 C-1 A1 3/8 C-17A C1 3/8 C-17B C1 3/9 C-17A 3/9 C-17B C1 BMPS2 BMP PC151g BMPC151g BMPC120c BMPC120c S E 1 0 0 T H S T 126TH AVE SE0423059002 04280000200428000025 0428000095 04280000950428000100 0428000105 0428000155 0428000160 0428000165 0428000190 0428000195 04280002000428000205 0428000210 0428000290 0428000290 0428100530 3449820290 3449820300 3449820310 3449820320 K i n g C o untyC i t y o f R entonPath: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I200+00361239 3/9 SCHDE5 EAST 050FT/WEST 050FT STA=203+76.41 HT=50FT ELE=440.87 3/8 SCHDE5 STA=200+3.60 EAST 050FT/WEST 050FT ELE = 438.00 3/7 DCT2D 90FT STA=197+97.16 HT=77FT ELE=444.87 400 420440 460480 380 500 520 540560 580600 620 640 660 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 3MATCHLINE SHEET: 5Date: 8/23/2018 Page 4 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT C1C120c BMP BMPT5.12 BMP T5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8!(D!(D&-3/6 C-1 A1 BMPC120c NE21STS T NEW P ORT CTNE OLYMPIAAVENE0423059035 0428100530 0428100540 0428100545 3449820140 3449820150 3449820160 3449820170 3449820190 3449820200 3449820210 3449820220 34498202303449820240 3449820260 3449820270 3449820280 3449820460 3449820470 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I195+00190+00615 3/6 DCT2D 95FT STA=191+72.13 HT=80FT ELE=401.63 852 400 420440 460480 380 500 520 540560 580600 400 420440 460 480 340 360380 320300 500520 540560 580600 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 4MATCHLINE SHEET: 6Date: 8/23/2018 Page 5 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT 340 360 320300 BMPC120c BMPC220i V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8 !(D!(D&-&-3/5 C-18A C1 3/5 C-18B C1#*#*MR01(Honey Creek)Type F BMPC151g 0423059035 0423059342 3888320090 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I185+00852 3/5 SCDE60 EAST 090FT/WEST 090FT STA=183+20.03 HT=90FT ELE=403.89 400 420440 460 480 340 360380 320300 280 260 500520 240 400 420440460 480 340 360380 320 300 280 260 500520 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 5MATCHLINE SHEET: 7Date: 8/23/2018 Page 6 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 888 !(D!(D&-3/4 C-1 A1 BMP C121d BMPS3 BMPS2 NE15 TH S T0423059023 0423059097 0423059269 0423059342 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I180+00175+00672 3/4 SCDE60 105FT STA=176+67.86 HT=91FT ELE=397.38 400 420440 460 480 340 360380 320 300 500520 540560 580600 400 420 440 460480 340 360380 320300 500 520 540560 580600 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 6MATCHLINE SHEET: 8Date: 8/23/2018 Page 7 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8888!(D!(D!(D!(D&-&-3/2 C-1 C1 3/3 C-1 C1 BMPC151g BMPC151g SR 9 0 0 0423059080 0423059097 0423059127 0423059145 0423059153 0423059269 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I170+00536401 3/3 DCA15 100FT STA=171+22.20 HT=100FT ELE=389.41 3/2 DCA15 090FT STA=167+21.64 HT=90FT ELE=391.71 400 420440 460 480 340 360 380 320300 500 520 540560 580600 400 420 440 460480 340 360380 320300 500 520 540560 580600 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 7MATCHLINE SHEET: 9Date: 8/23/2018 Page 8 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8!(D!(D&-3/1 C-1 A1 NE 12TH STLYNNWOOD AVE NE MONROE AVE NE 0423059096 04230591270423059169 0423059182 0423059316 0423059317 77361000057736100009773610001077361000157736100016 7801300000 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I165+00160+00564458 3/1 DCT2 125FT STA=161+67.96 HT=109FT ELE=383.42 400 420 440 460480 340 360380 320 500 520 540 560 580 600 400 420440 460480 340 360380 320 500 520 540560 580 600 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 8MATCHLINE SHEET: 10Date: 8/23/2018 Page 9 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle88 8 !(D!(D!(D!(D&-&-2/9 C-1 A1 2/10 C-1 A1#*BMPC120c BMPC120c MONROE AVE NE LYNNWOOD AVE NE 28548000302854800035285480004028548000452854800050 2854800055 28548000602854800065 285480007028548000752854800080 7227900028 7227900030 7801300000 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I155+00525 2/10 DCT2 100FT STA=156+96.08 HT=86FT ELE=390.15 2/9 DCT2 100FT STA=151+75.53 HT=86FT ELE=397.22 400 420440 460480 340 360380 320 500 520 540560 580 600620 400 420440 460 480 340 360380 320 500 520540 560580 600620 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 9MATCHLINE SHEET: 11Date: 8/23/2018 Page 10 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 !(D!(D&-2/8 C-1 A1BMP C120cNE10THST MONROE AVE NE 2854800080 2854800085285480009028548000952854800100 2854800105 2854800110 2854800115 2854800120 2854800125 7227900028 7809000005780900001078090000157809000020 7809200005 780920001078092000157809200020 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 150+00145+00533542 2/8 DCT2 110FT STA=146+42.17 HT=95FT ELE=393.88 400 420440 460 480 340 360380 320 500 520540 560580 600620 400 420440 460 480 340 360 380 320 500 520 540560 580 600620 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 10MATCHLINE SHEET: 12Date: 8/23/2018 Page 11 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8!(D!(D&-2/7 C-1 A1 BMP C120c NE 8TH STNE 7TH CTMONROE AVE NE 7809000025780900003078090000357809000040780900004578090000507809000055 780920002078092000257809200030780920003578092000407809200045780920005078092000557809200060780920006578092000707809200075 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I140+00615 542 2/7 DCT2 110FT STA=140+98.42 HT=95FT ELE=394.84 400 420440 460480 340 360 380 500 520 540560 580 600620 400 420 440 460 480 340360 380 500520 540 560 580 600620 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 11MATCHLINE SHEET: 13Date: 8/23/2018 Page 12 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8 888!(D!(D!(D!(D&-&-2/5 C-1 A1 2/6 C-1 A1 BMP C120c NE 7TH STNE 7TH PLMONROE AVE NE 7227800425 7227800426 7809200080 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 135+00130+00601 2/6 DCT2 115FT STA=134+85.06 HT=100FT ELE=386.81 2/5 DCT2 100FT STA=128+84.48 HT=86FT ELE=378.68 400 420 440 460 480 340360 380 320 500520 540 560 580 400 420 440 460 480 340 360380 320 300 280 500 520 540 560 580 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 12MATCHLINE SHEET: 14Date: 8/23/2018 Page 13 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8!(D!(D&-2/4 C-1 C1 BMPC151g BMPC120c NE 6TH PLNE 6TH STRENTON TECH ACRD MONROE AVE NE 7227800425 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I125+00120+00598 594 2/4 DCA15 085FT STA=122+86.01 HT=85FT ELE=378.32 400 420 440 460 480 340 360380 320 300280 500 520 540 560 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 13MATCHLINE SHEET: 15Date: 8/23/2018 Page 14 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle88!(D!(D&-2/3 C-1 A1 M ONRO E AVE NE RENTON TEC H A C R D72278004257227800500 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 120+00594 115+00652 2/3 DCT2 110FT STA=116+81.81 HT=95FT ELE=341.54 400 420 440 460 480 340 360380 320 300 280 500 520 540 560 580 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 14MATCHLINE SHEET: 16Date: 8/23/2018 Page 15 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle888!(D!(D!(D!(D&-&-&-2/1 C-18A C1 2/1 C-18B C1 2/2 C-1 C1#*BMPC120c BMPC151g NE 4TH STRENTON TECH ACRD 1623059058 1623059059 1623059111 1623059112 7227800500 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I110+00281 2/2 DCA15D 115FT STA=110+39.98 HT=115FT ELE=340.44 2/1 SCDE30 EAST 100FT/WEST 100FT STA=107+58.76 HT=100FT ELE=339.96 105+00400 420 440 460 480 340 360380 320300 280 500 520 540 560 400420440 460 480 340 360 380 320300 280 260 500520 540 560 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 15MATCHLINE SHEET: 17Date: 8/23/2018 Page 16 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle888!(D!(D&-1/7 C-1 A1 1434000010 14340000121434000020 1623059059 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 105+00100+00755 1/7 DCT2D 105FT STA=100+3.83 HT=91FT ELE=331.93 400 420 440 460 480 340 360380 320 300 280260 500520 540 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 16MATCHLINE SHEET: 18Date: 8/23/2018 Page 17 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPC120c V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 88888!(D!(D&-1/6 C-1 A1 BMPC121 BMPS3 1434000010 1434000020 1623059133 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I95+0090+00673585 1/6 DCT2 105FT STA=93+31.08 HT=91FT ELE=337.03 400 420 440 460 480 340 360380 320 300 280260 500520 540 240 400 420 440 460 480 340 360 380 320 300 280260 500520540 240 300 280260 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 17MATCHLINE SHEET: 19Date: 8/23/2018 Page 18 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPC120c V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 888!(D!(D!(D!(D&-&-1/4 C-1 A1 1/5 C-1 A1 BMPC121d BMPS3 BMPS3 BMP C220i SE1STSTINDEX AVE SE1434000010 1434000020 1623059133 4307300550 4307300560 4307300570 4307300580 4307300590 4307300600 4307300610 4307301240 4307310360 4307310370 4307310380 43073103904307310400 4307330340 4307350010 4307350020 4307351230 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I85+00583 585 1/5 DCT2 115FT STA=87+86.09 HT=100FT ELE=299.67 1/4 DCT2; 130FT STA=81+73.15 HT=113FT ELE=259.19 400 420 440 460 340 360 380 320300 280260 180 200 220240 300 280260 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 18MATCHLINE SHEET: 20Date: 8/23/2018 Page 19 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 88 8 !(D!(D!(D!(D&-&-1/3 C-1 A1 1/4 C-1 A1 #*BMPC220i BMPC203h BMPS3 BMPC220BMP C220 FERNDALEAVESE4307300390 4307300410 4307300420 4307300430 4307300460 4307300470 4307300480 4307300490 4307300500 4307300510 4307300520 4307300530 4307300540 4307301230 4307301240 430732022043073202304307320240430732025043073202604307320270 4307330270 4307330280 4307330290 4307330300 4307330310 4307330320 4307330330 4307330340 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 1/4 DCT2; 130FT STA=81+73.15 HT=113FT ELE=259.19 80+00515548 1/3DCT2D085FTSTA=76+58.13HT=73FT ELE=306.00 75+00400 420 440 460 480 340 360380 320 300 280 260 180 200 220 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 19MATCHLINE SHEET: 21Date: 8/23/2018 Page 20 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8888 88!(D!(D!(D!(D!(D&-&-&-1/2 C-18B C1 1/3 C-1 A1 1/2 C-18A C1 #*#*BMPC203 BMP S3 BMPC220i BMPC220i BMPC220iBMP C151g BMPC120c C O A L M I N E H A Z A R D FERNDALEAVESES E 3 R D S T 3955901130 4307300380 4307300390 4307300400 4307300410 4307300420 4307301220 4307301230 4307301260 4307320250430732026043073202704307320280430732029043073203004307320310 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 548 75+0070+00410 1/2 SCDE60 EAST 070FT/WEST 070FT STA=71+9.79 HT=70FT ELE=334.50 400 420 440 460 480 340 360380 320300 280 260 500520 220 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 20MATCHLINE SHEET: 22Date: 8/23/2018 Page 21 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8 8!(D!(D&-1/1 C-1 A1 Not Rated B M P C1 2 0COAL MINE HAZARD COA L M I N E H A Z A R D SR 169 1623059035 1623059131 4307301220430730TRCT 430732032043073203304307320340430732TR-W Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 410 65+001,524 1/1 DCT2D 090FT STA=66+89.56 HT=77FT ELE=333.62 400 340 360 380 320300 280 260 120 140160 180 200 220 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 21MATCHLINE SHEET: 23Date: 8/23/2018 Page 22 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle Cedar River [ND]Type S, Shoreline NR02Type Ns NR02Category II NR03Category III SR 169CEDAR RIVER TRLRIV E R VIE W P A R K WALK1623059012 16230590331623059078 162305HYDR Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I60+0055+001,524 320 300 280260 100 120 140160 180 200 220 240 4060 80 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 22MATCHLINE SHEET: 24Date: 8/23/2018 Page 23 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8!(D&-0/9 C-1 A1 BMPC220iBMPS2 SE8THSTHARRINGTON PL SE KIRKLAND AVE SE 1623059012 1623059078 1623059078 7701590000 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I50+00595 0/9DCT2D 100FTSTA=51+65.84 HT=86FT ELE=249.01 400420 340 360380 320300 280 260 120 140 160 180 200 220 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 23MATCHLINE SHEET: 25Date: 8/23/2018 Page 24 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT!BMPC151g Existing Pole 0/11 to remain V3 Date: 03/02/2021 §¨¦405 Renton Newcastle8!(D!(D !(D !(D !(D &- &- &-&- &- 0/8 C1 0/8 C-18A C1 115-5 115-4115-3 #* #* NR02Type Ns NR04Category III BMPC103a BMPC121 COAL MINE HAZARDH A R RIN G T O N PL S E SE 8T H S T SE 8THPL 2123059003 7701570000 7701590000 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I45+00697 0/8 SCDE90 EAST 100FT/WEST 100FT STA=45+62.15 HT=100FT ELE=275.79400 420 440 460 480 340 360 380 320 300 280260 500 200220 240 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I 0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 24MATCHLINE SHEET: 26Date: 8/23/2018 Page 25 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT C-18B BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8 8!(D!(D !(D !(D &- 0/7 C-1 A1 NR01(Ginger Creek)Type Np NR01Category III NR02Category IIINR02Category I I I D NR02 - E s t i m a t e d Category I I I NR02Category III BMPC121d BMPC105b BMPC101 BMPC121d FULL MAP EXTENT INCLUDES COAL MINE HAZARD 2023059001 2023059050 2123059003 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 40+0035+00702 0/7 DCT2D 110FT STA=38+95.26 HT=95FT ELE=360.45 400 420 440 460 480 340 360 380 320300 280 500520 540 560 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I 0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 25MATCHLINE SHEET: 27Date: 8/23/2018 Page 26 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 888 88!(D!(D!(D !(D !(D &-&- 0/5 C-1 A1 0/6 C-1 A1 NR02Category IIID BMPC121d BMP S2 BMPC101 BMPS2 FULL MAP EXTENT INCLUDES COAL MINE HAZARD FULL MAP EXTENT INCLUDES COAL MINE HAZARD C EDAR RIDGEDRSE 2023059001 2023059001 2023059050 2023059050 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I30+00700 0/6 DCT2 125FT STA=31+83.14 HT=109FT ELE=400.66 400 420 440 460 480 340360 380 500520 540 560 580 600 620 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I 0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 26MATCHLINE SHEET: 28Date: 8/23/2018 Page 27 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPC121d V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 8 8 8 !(D !(D!(D !(D !(D !(D !(D &- &- &- &- &-0/3C-19C10/5 C-1 A1 0/4 C-18A C1 0/4 C-18B C1 115-2 #* BMPC121d BMPC151g BMPS2 FULL MAP EXTENT INCLUDES COAL MINE HAZARDBEACON WAY S 2023059001 2023059002 2023059003 2023059066 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 25+0020+00546 0/5 DCT2D 125FT STA=24+98.52 HT=109FT ELE=414.55 0/4 SCDE110 EAST 070FT/WEST 070FT STA=19+47.02 HT=70FT ELE=430.97 299 0/3 DCDE2 075FT STA=17+38.25 HT=75FT ELE=430.35 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I 0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 27MATCHLINE SHEET: 29Date: 8/23/2018 Page 28 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle 88!(D!(D!(D!(D!(D!(D!(D!(D&-&-&-&-&-0CC0/1C-18BC10/2 C-19 C1 0/3 C-19 C1 0/4 C-18A C10/4 C-18B C1 0/1 C-18A C1 0/4C-18A115-2#*BMPS2BMP C140f BMPC151g FULL MAP EXTENT INCLUDES COAL MINE HAZARD COAL MINE HAZARD BEACON WAY S 2023059002 2023059003 2023059051 2023059062 2023059066 2023059066 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 20+000/4 SCDE110 EAST 070FT/WEST 070FT STA=19+47.02 HT=70FT ELE=430.97 15+00306 299 0/3 DCDE2 075FT STA=17+38.25 HT=75FT ELE=430.35 0/2 DCDE90 090FT STA=12+38.27 HT=90FT ELE=431.39 400 420440460 480 340 360380 320 500 520 540 560 580 600 620 640 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 28MATCHLINE SHEET: 30Date: 8/23/2018 Page 29 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT BMPT5.12BMPT5.12 BMPT5.12 V3 Date: 03/02/2021 §¨¦405 Renton Newcastle !(D!(D!(D &- &- &-0/1 C-18A C1 0/1 C-18B C1 0/2 C-19 C1BMPC151COAL MINE HAZARDZARDBEACON WAY S 2023059003 2023059051 2023059062 2023059066 Path: G:\Projects\Washington\Puget_Sound_Energy_007022\EnergizeEastsideMapbook_10059878\7.2_WP\Map_Docs\Renton\ConceptualDrainageMemo\PSE_Renton_TESC2.mxdProject Corridor &-Proposed Pole Location !(D Existing Pole Location–To Be Removed Transmission Line - Proposed Transmission Line - Existing Recommended Access- Proposed Pole Olympic UndergroundPipline (Approx. Location) Wastewater Utility Line Water Utility Line Underground Gas Utility Line Underground Phone/TV Utility Line Underground Power Utility Line Unknown Underground Utility Line #*Potential Stringing Site Stream Wetland Wetland or Stream Buffer Landslide Hazard Landslide Hazard 50ft Buffer Steep Slope Steep Slope 50ft Buffer Erosion Hazard Coal Mine Hazard Parcel City Jurisdiction Boundary I 332 0/2 DCDE90 090FT STA=12+38.27 HT=90FT ELE=431.39 10+00199 0/1 SCDE110/SCDE90 075FT STA10+35.18 HT=75FT ELE=443.43 400 420440 460 480 360380 500 520 540 560 580 600 620 640 Profile View Structure Conductor Ground Line Major Elevation Grid Major Station Grid Minor Station Grid I 0 25 50 Feet 1 inch = 50 feet MAP EXTENT SOURCES: Roads and Parcels - King County (2015), Aerial- King County (2015); Streams, Wetlands and Buffers,Landslide Hazard and Buffers, and Steep Slopes andBuffers from Watershed Company (2017). For cartographic purposes only. Note:Note: Underground utility lines are surveyed in thevicinity of poles only. Existing Lake Tradition poles aren'trepresented by new conductors because they are anexisting line, and are being represented due to the polesbeing replaced.MATCHLINE SHEET: 29Date: 8/23/2018 Page 30 of 30 BASED ON PSE ENGINEERINGDESIGN REVISION N RENTON TEMPORARY EROSION AND SEDIMENTCONTROL (TESC) PLAN BMPC120 5/7 C-16 A1 Proposed Pole Number Structure Type (See Appx. A) Construction Scenario Key (See Appx. B) BMP Key (See Appx. C) DRAFT V3 Date: 03/02/2021 STRUCTURE TYPES Appendix A Date: 8/23/2018 BASED ON PSE ENGINEERING DESIGN REVISION N RENTON Structure Type Naming Convention Description SCDE C-18 A/B Single circuit deadend SCT C-16 A/B Single circuit tangent DCT C-1 / C-19 Double circuit tangent (D denotes OHGW overhead groundwire) SCHDE C-17 A/B Single circuit horizontal deadend (only under SCL line) SCA C-2 A/B Single circuit angle *number after type in table denotes angle Eastside 230 ROW and structure options.dgn 8/16/2017 2:06:44 PM Structure Height 65'-105' 85'-90' 70'-120' 50' 90'-95' V3 Date: 03/02/2021 CONSTRUCTION SCENARIOS Appendix B Date: 8/23/2018 BASED ON PSE ENGINEERING DESIGN REVISION N RENTONStructure Type Typical Construction Scenario (Not in critical area) C-1 A1 C-2 C1 C-16 A1 C-17 C1 C-18 C1 V3 Date: 03/02/2021 BEST MANAGEMENT PRACTICES Appendix C Date: 8/23/2018 BASED ON PSE ENGINEERING DESIGN REVISION N RENTON BMP Code Title Application Notes C101 Preserving Natural Vegetation Minimize disturbance to vegetation wherever possible. Maintaining vegetative cover on slopes and near water bodies is critical. Where possible, construction should be scheduled to maintain vegetation for as long as possible. C103a High Visibility Fencing High visibility plastic fence (HVF) shall be composed of a high-density polyethylene material and shall be at least four feet in height. Posts for the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. HVF should be used to establish boundaries of all work areas as well as wetlands. HVF should be installed prior to clearing activities and should remain in place until work is complete in a given area. Silt fence can be used in lieu of HVF if it is highly visible and is at least 3' tall. C105b Stabilized Construction Entrance The construction entrance shall be composed of 4-8" quarry spalls at 1' deep with a geotextile fabric base. Where possible, the access should be a minimum of 15 feet wide and 100' long. If the entrance intersects a ditch, install a culvert to permit free flow through the ditch. In instances where ground conditions do not require the use of geotextile and rock installed at the entrance is to remain after completion of the work, the geotextile can be omitted. C120c Temporary and Permanent Seeding Apply seed to disturbed soils if they are to remain undisturbed for at least 30 days. The optimum seeding windows are from 4/1 to 6/30 and 9/1 through 10/1. Seed applied during the summer months will require irrigation until 75% area coverage is achieved. Seed applied during the winter months will require a mulch cover to prevent seed from washing away. C121d Mulching Mulch covers should be 2" thick at a minimum. Mulch should be spread over areas of disturbed soils that require temporary cover for less than 30 days. C123e Plastic Covering Plastic sheeting can be used to temporary stabilize small areas of disturbed soils. Use caution when applying plastic sheeting as it can increase run-off velocity and concentration which can contribute to erosion. Use check dams in these areas to mitigate these effects. C140f Dust Control High vehicle and equipment traffic on access roads and construction entrances make them particularly susceptible to dust generation. Vehicle speeds should be lowered where dust is being generated. Improve road surface with mulch or gravel to provide a barrier between vehicle tires and fines. Water trucks can also be used in these areas for temporary lower-traffic applications. Track-out at construction entrances is considered a problem when dust on the road becomes airborne when vehicles pass over. These areas should be swept and kept free of fines at all times. C151g Concrete Handling Eco-pans should be used to collect all extra concrete. Excess concrete should be disposed of off site. Cover eco pans and concrete formwork with plastic sheeting to prevent rainwater contamination. Eco-pans shall note be located within City of Renton rights-of-way. C203h Water Bars For narrow access roads, water bars can be used to direct stormwater to vegetated areas and decrease runoff velocity and gullying. Water bars should be a minimum of 8" high and spaced at 50' to 125' intervals (decreasing as slope increases). C207h Check Dams Check dams reduce the velocity and erosivity of stormwater and should be used ditches that may be affected by project stormwater. Straw wattles can be laid perpendicular to the slope of a ditch spaced such that the base of the upstream check dam is at the same elevation as the peak of the downstream check dam. C220i Storm Drain Inlet Protection Storm drains within 500' of a work area or those downstream of the work area should be protected with inserts. Gravel bags can also be used in a check dam application to create stilling ponds directly upstream of catch basins that allow sediment to separate from stormwater flows. C233j Silt Fence C235k Wattles S1 Wetland Matting S2 Asphalt Protection S3 Gravel Stabilization S4 Steep Slope Setback Silt fence should be applied downslope of all disturbed areas and along the perimeter of sensitive areas. Silt fence shall be wire-backed with metal posts on 6' centers and keyed in at least 4" at the base. In areas where keying will cause undue soil disturbance, straw wattles staked in along the base of a silt fence to serve as a key. In all cases, silt fence should be installed such that the post is downhill of the fabric (if pre- sewn silt fence is used, the seam will face away from the work). Wattles should be used to temporarily contain soils in disturbed areas and slopes. Install wattles perpendicular to the direction of flow. Wattles should be keyed into soils so that the wattle is securely fastened to the ground. Wattles should generally be placed at 10-25' intervals. Mats should be used in areas where permanent access improvements are not possible or practical and equipment access is required. Hog fuel can be applied below mats to stabilize accesses. Measures shall be taken to prevent damage to pavement and curbs from vehicles driving on them abnormally. This typically includes the use of matting to prevent the breakdown of pavement edges and can be used in conjunction with C105. Gravel shall be applied to all areas that are susceptible to dusting in dry weather and/or accelerated erosion. Do not add gravel to severely destabilized areas without including a geotextile base. Applied gravel should be free of fines that may contribute to dusting and/or turbidity. Gravel will be removed after work is completed. The work area is near a steep slope that is susceptible to erosion and landslide hazards. Refer to the authority having jurisdiction's requirements for setbacks and working in this area. T5.12 Sheet Flow Dispersion Sheet flow dispersion should be used for poles with impervious foundations. a D.2.1.1.1 Plastic or Metal Fence, 2017 City of Renton Surface Water Design Manual b D.2.1.4.1 Stabilized Construction Entrance, 2017 City of Renton Surface Water Design Manual c D.2.1.2.6 Temporary and Permanent Seeding, 2017 City of Renton Surface Water Design Manual d D.2.1.2.2 Mulching, 2017 City of Renton Surface Water Design Manual e D.2.1.2.4 Plastic Covering, 2017 City of Renton Surface Water Design Manual f D.2.1.8 Dust Control, 2017 City of Renton Surface Water Design Manual g D.2.2.1 Concrete Handling, 2017 City of Renton Surface Water Design Manual h D.2.1.3 Triangular Silt Dike (Geotextile Encased Check Dam), 2017 City of Renton Surface Water Design Manual i D.2.1.5.3 Storm Drain Inlet Protection, 2017 City of Renton Surface Water Design Manual j D.2.1.3.1 Silt Fence, 2017 City of Renton Surface Water Design Manual k D.2.1.2.5 Straw Wattles, 2017 City of Renton Surface Water Design Manual V3 Date: 03/02/2021 Appendix B. BMP Details D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-11 facility, runoff treatment facility, and on-site BMP areas [existing or proposed] shall not be used for this purpose). 10.Control Pollutants: Stormwater pollution prevention (SWPPS) measures are required to prevent,reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsiteequipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. Section D.2.2 describesBMPs specific to this purpose; additionally, several of the ESC BMPs described herein are applicable. 11.Protect Existing and Proposed Stormwater Facilities and On-site BMPs: Sedimentation and soilcompaction reduce the infiltration capacity of native and engineered soils. Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilitiesand on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities andon-site BMPs. 12.Maintain Protective BMPs:Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing BMPs/facilities and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. 13.Manage the Project:Coordination and timing of site development activities relative to ESC concerns, and timely inspection, maintenance and update of protective measures are necessary toeffectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. D.2.1.1 CLEARING LIMITS Prior to any site clearing or grading, those areas that are to remain undisturbed during project construction shall be delineated. At a minimum, clearing limits shall be installed at the edges of all critical area buffersand any other areas required to be left uncleared such as portions of the site subject to clearing limits under RMC 4-4-060, areas around significant trees identified to be retained, on-site BMP areas to be protected,and other areas identified to be left undisturbed to protect sensitive features. Purpose:The purpose of clearing limits is to prevent disturbance of those areas of the project site that arenot designated for clearing or grading. This is important because limiting site disturbance is the single most effective method for reducing erosion. Clearing limits may also be used to control construction traffic, thus reducing the disturbance of soil and limiting the amount of sediment tracked off site. When to Install: Clearing limits shall be installed prior to the clearing and/or grading of the site. Measures to Use: Marking clearing limits by delineating the site with a continuous length of brightly colored survey tape is sometimes sufficient. The tape may be supported by vegetation or stakes, and itshall be 3 to 6 feet high and highly visible. Critical areas and their buffers require more substantial protection and shall be delineated with plastic or metal safety fences or stake and wire fences. Fencing may be required at the City’s discretion to control construction traffic or at any location where greater protection is warranted. Permanent fencing may also be used if desired by the applicant. Silt fence, incombination with survey flagging, is also an acceptable method of marking critical areas and their buffers. D.2.1.1.1 PLASTIC OR METAL FENCE Code: FE Symbol: Purpose Fencing is intended to (1) restrict clearing to approved limits; (2) prevent disturbance of critical areas, their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect areas where marking with survey tape may not provide adequate protection. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-12 Conditions of Use To establish clearing limits, plastic or metal fence may be used: 1.At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2.As necessary to control vehicle access to and on the site (see Sections D.2.1.4.1 and D.2.1.4.2). Design and Installation Specifications 1.The fence shall be designed and installed according to the manufacturer’s specifications. 2.The fence shall be at least 3 feet high and must be highly visible. 3.The fence shall not be wired or stapled to trees. Maintenance Requirements 1.If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. 2.Disturbance of a critical area, critical area buffer, native growth retention area, or any other area required to be left undisturbed shall be reported to the City for resolution. D.2.1.2 COVER MEASURES Temporary and permanent cover measures shall be provided to protect all disturbed areas, including the faces of cut and fill slopes. Temporary cover shall be installed if an area is to remain unworked for more than seven days during the dry season (May 1 to September 30) or for more than two consecutive working days during the wet season (October 1 to April 30). These time limits may be relaxed if an area poses alow risk of erosion due to soil type, slope gradient, anticipated weather conditions, or other factors. Conversely, the City may reduce these time limits if site conditions warrant greater protection (e.g., adjacent to significant aquatic resources or highly erosive soils) or if significant precipitation (see Section D.2.4.2) is expected. Any area to remain unworked for more than 30 days shall be seeded orsodded, unless the City determines that winter weather makes vegetation establishment infeasible. During the wet season, slopes and stockpiles at 3H:1V or steeper and with more than ten feet of vertical reliefshall be covered if they are to remain unworked for more than 12 hours. Also during the wet season, the material necessary to cover all disturbed areas must be stockpiled on site. The intent of these coverrequirements is to have as much area as possible covered during any period of precipitation. Purpose: The purpose of covering exposed soils is to prevent erosion, thus reducing reliance on less effective methods that remove sediment after it is entrained in runoff. Cover is the only practical method of reducing turbidity in runoff. Structural measures, such as silt fences and sediment ponds, are only capable of removing coarse particles and in most circumstances have little to no effect on turbidity. When to Install: Any exposed soils that will remain unworked for more than the time limit set above shall be covered by the end of the working day. If the exposed area is to remain unworked for more than 30 days, the area shall be seeded with the temporary seed mix or an equivalent mix that will provide rapid protection (see Section D.2.1.2.6). If the disturbed area is to remain unworked for a year or more or if the area has reached final grade, permanent seed mix or an equivalent mix shall be applied. Measures to Use: Cover methods include the use of surface roughening, mulch, erosion control nets and blankets, plastic covering, seeding, and sodding. Mulch and plastic sheeting are primarily intended to protect disturbed areas for a short period of time, typically days to a few months. Seeding and sodding are measures for areas that are to remain unworked for months. Erosion nets and blankets are to be used in conjunction with seeding steep slopes. The choice of measures is left to the designer; however, there are restrictions on the use of these methods, which are listed in the “Conditions of Use” and the “Design and Installation Specifications” sections for each measure. The methods listed are by no means exhaustive. Variations on the standards presented here are encouraged if other cost-effective products or methods provide substantially equivalent or superior performance. Also, D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-13 the details of installation can, and should, vary with the site conditions. A useful reference on the application of cover measures in the Puget Sound area is Improving the Cost Effectiveness of Highway Construction Site Erosion and Pollution Control, Horner, Guedry, and Kortenhof (1990). D.2.1.2.1 SURFACE ROUGHENING Purpose The purpose of surface roughening is to aid in the establishment of vegetative cover and to reduce runoff velocity, increase infiltration, and provide for sediment trapping through the provision of a rough soil surface. The rough soil surface may be created by operating a tiller or other equipment on the contour to form horizontal depressions or by leaving slopes in a roughened condition by not fine grading. Conditions of Use 1.All slopes steeper than 3H:1V and greater than 5 vertical feet require surface roughening. 2.Areas with grades steeper than 3H:1V should be roughened to a depth of 2 to 4 inches prior to seeding. 3.Areas that will not be stabilized immediately may be roughened to reduce runoff velocity until seeding takes place. 4. Slopes with a stable rock face do not require roughening. 5. Slopes where mowing is planned should not be excessively roughened. Design and Installation Specifications There are different methods for achieving a roughened soil surface on a slope, and the selection of an appropriate method depends upon the type of slope. Roughening methods include stair-step grading, grooving, contour furrows, and tracking. See Figure D.2.1.2.A for information on tracking and contourfurrows. Factors to be considered in choosing a method are slope steepness, mowing requirements, and whether the slope is formed by cutting or filling. Sole reliance on roughening for temporary erosion control is of limited effectiveness in intense rainfall events. Stair-step grading may not be practical for sandy, steep, or shallow soils. 1.Disturbed areas that will not require mowing may be stair-step graded, grooved, or left rough after filling 2. Stair Step grading is particularly appropriate in soils containing large amounts of soft rock. Each “step”catches material that sloughs from above, and provides a level site where vegetation canbecome established. Stairs should be wide enough to work with standard earth moving equipment. Stair steps must be on contour or gullies will form on the slope. 3.Areas that will be mowed (slopes less steep than 3H:1V) may have small furrows left by disking, harrowing, raking, or seed-planting machinery operated on the contour. 4.Graded areas with slopes greater than 3H:1V but less than 2H:1V should be roughened before seeding. This can be accomplished in a variety of ways, including “track walking” or driving a crawlertractor up and down the slope, leaving a pattern of cleat imprints parallel to slope contours. 5. Tracking is done by operating equipment up and down the slope to leave horizontal depressions in thesoil. Maintenance Standards Periodically check roughened, seeded, planted, and mulched slopes for rills and gullies, particularly after a significant storm event. Fill these areas slightly above the original grade, then re-seed and mulch as soon as possible. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-14 FIGURE D.2.1.2.A SURFACE ROUGHENING 50'(15 m ) 1 GROOVES WILL CATCH SEED, FERTILIZER, MULCH, RAINFALLAND DECREASE RUNOFF. "TRACKING" WITH MACHINERY UP AND DOWNTHE SLOPE PROVIDES GROOVES THAT WILL CATCH SEED, RAINFALL AND REDUCE RUNOFF. CONTOUR FURROWS TRACKING 6" MIN.(150mm) 3 MAX. SURFACE ROUGHENING BY TRACKING AND CONTOUR FURROWS NTS D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-15 D.2.1.2.2 MULCHING Code: MU Symbol: Purpose The purpose of mulching soils is to provide immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous variety of mulches that may be used. Only the most common types are discussed in this section. Conditions of Use As a temporary cover measure, mulch should be used: 1. On disturbed areas that require cover measures for less than 30 days 2. As a cover for seed during the wet season and during the hot summer months 3. During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical relief. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table D.2.1.2.A. Note: Thicknesses may be increased for disturbed areas in or near critical areas or other areas highly susceptible to erosion. Maintenance Standards 1.The thickness of the cover must be maintained. 2. Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the drainage problem shall be assessed and alternate drainagesuch as interceptor swales may be needed to fix the problem and the eroded area remulched. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-16 TABLE D.2.1.2.A MULCH STANDARDS AND GUIDELINES Mulch Material Quality Standards Application Rates Remarks Straw Air-dried; free from undesirable seed and coarse material 2″–3″ thick; 5 bales per 1,000 sf or 2– 3 tons per acre Cost-effective protection when applied with adequate thickness. Hand-application generally requires greater thickness than blown straw. Straw should be crimped to avoid wind blow. The thickness of straw may be reduced by half when used in conjunction with seeding. Wood Fiber Cellulose No growth inhibiting factors Approx. 25–30 lbs per 1,000 sf or 1,500–2,000 lbs per acre Shall be applied with hydromulcher. Shall not be used without seed and tackifier unless the application rate is at least doubled. Some wood fiber with very long fibers can be effective at lower application rates and without seed or tackifier. Compost No visible water or dust during handling. Must be purchased from supplier with Solid Waste Handling Permit. 2″ thick min.; approx. 100 tons per acre (approx. 1.5 cubic feet per square yard) More effective control can be obtained by increasing thickness to 3″ (2.25 cubic feet per square yard). Excellent mulch for protecting final grades until landscaping because it can be directly seeded or tilled into soil as an amendment. Compost may not be used in Sensitive Lake7 basins unless analysis of the compost shows no phosphorous release. Hydraulic Matrices (Bonded Fiber Matrix [BFM]) This mulch category includes hydraulic slurries composed of wood fiber, paper fiber or a combination of the two held together by a binding system. The BFM shall be a mixture of long wood fibers and various bonding agents. Apply at rates from 3,000 lbs per acre to 4,000 lbs per acre and based on manufacturers recommendations The BFM shall not be applied immediately before, during or immediately after rainfall so that the matrix will have an opportunity to dry for 24 hours after installation. Application rates beyond 2,500 pounds may interfere with germination and are not usually recommended for turf establishment. BFM is generally a matrix where all fiber and binders are in one bag, rather than having to mix components from various manufacturers to create a matrix. BFMs can be installed via helicopter in remote areas. They are approximately $1,000 per acre cheaper to install. Chipped Site Vegetation Average size shall be several inches. 2″ minimum thickness This is a cost-effective way to dispose of debris from clearing and grubbing, and it eliminates the problems associated with burning. Generally, it should not be used on slopes above approx. 10% because of its tendency to be transported by runoff. It is not recommended within 200 feet of surface waters. If seeding is expected shortly after mulch, the decomposition of the chipped vegetation may tie up nutrients important to grass establishment. 7 Sensitive lake means a lake that has proved to be particularly prone to eutrophication; the City did not have any lakes that had this designation at the time of SWDM adoption. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-17 D.2.1.2.3 NETS AND BLANKETS Code: NE Symbol: Purpose Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets are strands of material woven into an open, but high-tensile strength net (for example, jute matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: 1. For permanent stabilization of slopes 2H:1V or greater and with more than 10 feet of vertical relief. 2. In conjunction with seed for final stabilization of a slope, not for temporary cover. However, they may be used for temporary applications as long as the product is not damaged by repeated handling. In fact, this method of slope protection is superior to plastic sheeting, which generates high-velocity runoff (see Section D.2.1.2.4). 3. For drainage ditches and swales (highly recommended). The application of appropriate netting or blanket to drainage ditches and swales can protect bare soil from channelized runoff while vegetation is established. Nets and blankets also can capture a great deal of sediment due to their open, porous structure. Synthetic nets and blankets may be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. Design and Installation Specifications 1. See Figure D.2.1.2.B and Figure D.2.1.2.C for typical orientation and installation of nettings and blankets. Note: Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. 2. With the variety of products available, it is impossible to cover all the details of appropriate use and installation. Therefore, it is critical that the design engineer thoroughly consults the manufacturer’s information and that a site visit takes place in order to ensure that the product specified is appropriate. 3. Jute matting must be used in conjunction with mulch (Section D.2.1.2.2). Excelsior, woven straw blankets, and coir (coconut fiber) blankets may be installed without mulch. There are many other types of erosion control nets and blankets on the market that may be appropriate in certain circumstances. Other types of products will have to be evaluated individually. In general, most nets (e.g., jute matting) require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. 4. Purely synthetic blankets are allowed but shall only be used for long-term stabilization of waterways. The organic blankets authorized above are better for slope protection and short-term waterway protection because they retain moisture and provide organic matter to the soil, substantially improving the speed and success of re-vegetation. Maintenance Standards 1. Good contact with the ground must be maintained, and there must not be erosion beneath the net or blanket. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-18 2. Any areas of the net or blanket that are damaged or not in close contact with the ground shall be repaired and stapled. 3. If erosion occurs due to poorly controlled drainage, the problem shall be fixed and the eroded area protected. FIGURE D.2.1.2.B WATERWAY INSTALLATION FIGURE D.2.1.2.C SLOPE INSTALLATION •DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLSTO MOLD TO ANY IRREGULARITIES. •SLOPE SURFACE SHALL BE SMOOTH BEFORE PLACEMENT FOR PROPER SOIL CONTACT. •ANCHOR, STAPLE, AND INSTALL CHECK SLOTS AS PER MANUFACTURER'S RECOMMENDATIONS. •AVOID JOINING MATERIAL IN THE CENTER OF THE DITCH. •LIME, FERTILIZE AND SEED BEFORE INSTALLATION. MIN.4" OVERLAP' MIN.6"OVERLAP SLOPE SURFACE SHALL BE SMOOTH BEFOREPLACEMENT FOR PROPER SOIL CONTACT STAPLING PATTERN AS PERMANUFACTURER'S RECOMMENDATION MIN. 2" OVERLAP LIME, FERTILIZE AND SEED BEFOREINSTALLATION. PLANTING OF SHRUBS, TREES, ETC. SHOULD OCCUR AFTER INSTALLATION DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLS TO MOLD TO ANY IRREGULARITIES FOR SLOPES LESS THAN 3H:1V, ROLLS MAY BE PLACEDIN HORIZONTAL STRIPS BRING MATERIAL DOWN TO A LEVELAREA, TURN THE END UNDER 4" ANDSTAPLE AT 12" INTERVALS ANCHOR IN 6"x6" MIN.TRENCH AND STAPLEAT 12" INTERVALS STAPLE OVERLAPS MAX. 5' SPACING IF THERE IS A BERM AT THE TOP OF SLOPE, ANCHORUPSLOPE OF THE BERM MIN. 6" OVERLAP D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-19 D.2.1.2.4 PLASTIC COVERING Code: PC Symbol: Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use 1. Plastic covering may be used on disturbed areas that require cover measures for less than 30 days. 2. Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term applications. 3. Clear plastic sheeting may be used over newly-seeded areas to create a greenhouse effect and encourage grass growth. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass. 4. Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. Note: There have been many problems with plastic, usually attributable to poor installation and maintenance. However, the material itself can cause problems, even when correctly installed and maintained, because it generates high-velocity runoff and breaks down quickly due to ultraviolet radiation. In addition, if the plastic is not completely removed, it can clog drainage system inlets and outlets. It is highly recommended that alternatives to plastic sheeting be used whenever possible and that its use be limited. Design and Installation Specifications 1. See Figure D.2.1.2.D for details. 2. Plastic sheeting shall have a minimum thickness of 0.06 millimeters. 3. If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. FIGURE D.2.1.2.D PLASTIC COVERING TIRES, SANDBAGS, OREQUIVALENT MAY BE USEDTO WEIGHT PLASTIC SEAMS BETWEEN SHEETS MUST OVERLAP A MINIMUM OF 12" AND BE WEIGHTED OR TAPED TOE IN SHEETINGIN MINIMUM 4"X4"TRENCH PROVIDE ENERGY DISSIPATIONAT TOE WHEN NEEDED 10' MAX. 10' MAX. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-20 Maintenance Standards for Plastic Covering 1. Torn sheets must be replaced and open seams repaired. 2. If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced. 3. When the plastic is no longer needed, it shall be completely removed. D.2.1.2.5 STRAW WATTLES Code: SW Symbol: Purpose Wattles are erosion and sediment control barriers consisting of straw wrapped in biodegradable tubular plastic or similar encasing material. Wattles may reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Straw wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. The wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. Conditions of Use 1. Install on disturbed areas that require immediate erosion protection. 2. Use on slopes requiring stabilization until permanent vegetation can be established. 3. Can be used along the perimeter of a project, as a check dam in unlined ditches and around temporary stockpiles 4. Wattles can be staked to the ground using willow cuttings for added revegetation. 5. Rilling can occur beneath and between wattles if not properly entrenched, allowing water to pass below and between wattles Design and Installation Specifications 1. It is critical that wattles are installed perpendicular to the flow direction and parallel to the slope contour. 2. Narrow trenches should be dug across the slope, on contour, to a depth of 3 to 5 inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and during high rainfall events, the trenches should be dug to a depth of 5 to 7 inches, or ½ to 2/3 of the thickness of the wattle. 3. Start construction of trenches and installing wattles from the base of the slope and work uphill. Excavated material should be spread evenly along the uphill slope and compacted using hand tamping or other method. Construct trenches at contour intervals of 3 to 30 feet apart depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches should be constructed. 4. Install the wattles snugly into the trenches and abut tightly end to end. Do not overlap the ends. 5. Install stakes at each end of the wattle, and at 4 foot centers along the entire length of the wattle. 6. If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. 7. At a minimum, wooden stakes should be approximately ¾ x ¾ x 24 inches. Willow cuttings or 3/8 inch rebar can also be used for stakes. 8. Stakes should be driven through the middle of the wattle, leaving 2 to 3 inches of the stake protruding above the wattle. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-21 Maintenance Standards 1. Inspect wattles prior to forecasted rain, daily during extended rain events, after rain events, weekly during the wet season, and at two week intervals at all other times of the year. 2. Repair or replace split, torn, raveling, or slumping wattles 3. Remove sediment accumulations when exceeding ½ the height between the top of the wattle and the ground surface. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-22 FIGURE D.2.1.2.E STRAW WATTLES 1.STRAW ROLL INSTALLATION REQUIRES THE PLACEMENT AND SECURE STAKING OF THE ROLL IN A TRENCH, 3" x 5" (75-125mm) DEEP, DUG ON CONTOUR. 2.RUNOFF MUST NOT BE ALLOWED TO RUN UNDER OR AROUND ROLL. ROLL SPACING DEPENDS ON SOIL TYPE AND SLOPE STEEPNESS STRAW ROLLS MUST BE PLACED ALONG SLOPE CONTOURS 3'-4' (1.2m) 10'-25' (3-8m) 3"-5"(75-125mm) ADJACENT ROLLSSHALL TIGHTLY ABUT SEDIMENT, ORGANIC MATTER, AND NATIVE SEEDS ARE CAPTURED BEHIND THE ROLLS LIVE STAKE 1" x 1" STAKE 8"-10" DIA. (200-250mm) NOTES: STRAW WATTLESNTS D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-23 D.2.1.2.6 TEMPORARY AND PERMANENT SEEDING Code: SE Symbol: Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use 1. Seeding shall be used throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. 2. Vegetation-lined channels shall be seeded. Channels that will be vegetated should be installed before major earthwork and hydroseeded or covered with a Bonded Fiber Matrix (BFM). 3. Retention/detention ponds shall be seeded as required. 4. At the City’s discretion, seeding without mulch during the dry season is allowed even though it will take more than seven days to develop an effective cover. Mulch is, however, recommended at all times because it protects seeds from heat, moisture loss, and transport due to runoff. 5. Prior to the beginning of the wet season, all disturbed areas shall be reviewed to identify which ones can be seeded in preparation for the winter rains (see Section D.2.4.2). Disturbed areas shall be seeded within one week of the beginning of the wet season. A sketch map of those areas to be seeded and those areas to remain uncovered shall be submitted to the CED inspector. The CED inspector may require seeding of additional areas in order to protect surface waters, adjacent properties, or drainage facilities. 6. At final site stabilization, all disturbed areas not otherwise vegetated or stabilized shall be seeded and mulched (see Section D.2.4.5). Design and Installation Specifications 1. The best time to seed is fall (late September to October) or in spring (mid-March to June). Irrigation is required during the first summer following installation if seeding occurs in spring or summer or during prolonged dry times of year. Areas may also be seeded during the winter months, but it may take additional spring seeding applications to develop a dense groundcover due to cold temperatures. The application and maintenance of mulch is critical for winter seeding. 2. To prevent seed from being washed away, confirm that all required surface water control measures have been installed. 3. The seedbed should not be compacted because soils that are well compacted will not vegetate as quickly or thoroughly. Slopes steeper than 3H:1V shall be surface roughened. Roughening can be accomplished in a variety of ways, but the typical method is track walking, or driving a crawling tractor up and down the slope, leaving cleat imprints parallel to the slope contours. 4. In general, 10-20-20 N-P-K (nitrogen-phosphorus-potassium) fertilizer may be used at a rate of 90 pounds per acre. Slow-release fertilizers are preferred because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertilizer needed. This will prevent the over- application of fertilizer. Disturbed areas within 200 feet of water bodies and wetlands must use slow-release low-phosphorus fertilizer (typical proportions 3-1-2 N-P-K). 5. The following requirements apply to mulching: a) Mulch is always required for seeding slopes greater than 3H:1V (see Section D.2.1.2.2). b) If seeding during the wet season, mulch is required. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-24 c) The use of mulch may be required during the dry season at the City’s discretion if grass growth is expected to be slow, the soils are highly erodible due to soil type or gradient, there is a water body close to the disturbed area, or significant precipitation (see Section D.2.4.2) is anticipated before the grass will provide effective cover. d) Mulch may be applied on top of the seed or simultaneously by hydroseeding. 6. Hydroseeding is allowed as long as tackifier is included. Hydroseeding with wood fiber mulch is adequate during the dry season. Application of hydroseeded wood fiber mulch should be appropriate for slope angle. Follow manufacturer specifications for application rates. 7. Areas to be permanently landscaped shall use soil amendments. Good quality topsoil shall be tilled into the top six inches to reduce the need for fertilizer and improve the overall soil quality. Most native soils will require the addition of four inches of well-rotted compost to be tilled into the soil to provide a good quality topsoil. Compost used should meet specifications provided in Reference Section 11-C of the SWDM. 8. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetland mix, shall be applied at a rate of 80 to 100 seeds per square foot. Wet sites should apply 120 to 150 seeds per square foot. Local suppliers should be consulted for information on current Pure Live Seed (PLS) rates and species specific seeds per pound in order to determine seed mix PLS pounds of seed per acre. The appropriate mix depends on a variety of factors, including exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by the City may be used. Table D.2.1.2.B presents the standard mix for those areas where t a temporary or permanent vegetative cover is required. The following mix assumes a desired 150 seeds per square foot and should be applied at approximately 37 pounds of pure live seed per acre. TABLE D.2.1.2.B EROSION CONTROL SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Spike bentgrass/Agrostis exarata 6 9 0.1 California brome/Bromus carinatus 15 23 9.8 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 Blue wildrye/Elymus glaucus 18 27 10.7 California oatgrass/Danthonia californica 18 27 5.6 Native red fescue/Festuca rubra var. rubra 18 27 2.4 Meadow barley/Hordeum brachyantherum 10 15 7.7 Table D.2.1.2.C provides just one recommended possibility for landscaping seed. It assumes a desired 100 seeds per square foot and should be applied at 12 pounds of pure live seed per acre. TABLE D.2.1.2.C LANDSCAPING SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Sideoats grama/Bouteloua curtipendula 20 30 6.8 California oatgrass/Danthonia californica 20 30 6.2 Native red fescue/Festuca rubra var. rubra 30 45 3.9 Prairie junegrass/Koeleria macrantha 30 45 0.8 D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-25 This turf seed mix in Table D.2.1.2.D is for dry situations where there is no need for much water. The advantage is that this mix requires very little maintenance. TABLE D.2.1.2.D LOW-GROWING TURF SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Hard fescue/Festuca brevipila 25 20 1.5 Sheep fescue/Festuca ovina 30 24 1.5 Native red fescue/Festuca rubra var. rubra 25 20 1.7 Prairie junegrass/Koeleria macrantha 20 16 0.3 Table D.2.1.2.E presents a mix recommended for bioswales and other intermittently wet areas. The mix assumes a desired 150 seeds per square foot and approximately 29 pounds of pure live seed per acre. Sod shall generally not be used for bioswales because the seed mix is inappropriate for this application. Sod may be used for lining ditches to prevent erosion, but it will provide little water quality benefit during the wet season. TABLE D.2.1.2.E BIOSWALE SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre American sloughgrass/Beckmannia syzigachne 15 23 0.9 Tufted hairgrass/Deschampsia cespitosa 20 30 0.5 Blue wildrye/Elymus glaucus 18 27 10.7 Native red fescue/Festuca rubra var. rubra 20 30 2.6 Meadow barley/Hordeum brachyantherum 12 18 9.2 Northwestern mannagrass/Glyceria occidentalis 15 23 4.9 The seed mix shown in Table D.2.1.2.F is a recommended low-growing, non-invasive seed mix appropriate for very wet areas that are not regulated wetlands (if planting in wetland areas, see Section 6.3.1 of the SWDM). Other mixes may be appropriate, depending on the soil type and hydrology of the area. This mixture assumes a target goal of 150 seeds per square foot and should be applied at a rate of 36 pounds per acre. TABLE D.2.1.2.F WET AREA SEED MIX* Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre California brome/Bromus carinatus 15 23 9.8 Columbia brome/Bromus vulgaris 18 27 8.1 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 California oatgrass/Danthonia californica 15 23 4.7 Native red fescue/Festuca rubra var. rubra 17 26 2.2 Western manna grass/Glyceria occidentalis 10 15 3.3 Meadow barley/Hordeum brachyantherum 10 15 7.7 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-26 The meadow seed mix in Table D.2.1.2.G is recommended for areas that will be maintained infrequently or not at all and where colonization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. This seed mix assumes a target goal of 120 seeds per square foot and an application rate of 23 pounds of pure live seed per acre. TABLE D.2.1.2.G MEADOW SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Common yarrow/Achillea millefolium 4 5 0.1 Pearly everlasting/Anaphalis margartacae 1 1 0.0 California brome/Bromus carinatus 15 18 7.8 California oatgrass/Danthonia californica 15 18 3.7 Blue wildrye/Elymus glaucus 16 19 7.6 Festuca idahoensis 15 18 1.7 Native red fescue/Festuca rubra var. rubra 18 22 1.9 Sickle keeled lupine/Lupinus albicaulis 1 1 2.2 Fowl bluegrass/Poa palustris 15 18 0.4 Maintenance Standards for Temporary and Permanent Seeding 1. Any seeded areas that fail to establish at least 80 percent cover within one month shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding or nets/blankets, shall be used. If winter weather prevents adequate seed establishment and growth, this time limit may be relaxed at the discretion of the City when critical areas would otherwise be protected. 2. After adequate cover is achieved, any areas that experience erosion shall be re-seeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area re-seeded and protected by mulch. 3. Seeded areas shall be supplied with adequate moisture, but not watered to the extent that it causes runoff. D.2.1.2.7 SODDING Code: SO Symbol: Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: 1. Disturbed areas that require short-term or long-term cover 2. Disturbed areas that require immediate vegetative cover 3. All waterways that require vegetative lining (except biofiltration swales—the seed mix used in most sod is not appropriate for biofiltration swales). Waterways may also be seeded rather than sodded, and protected with a net or blanket (see Section D.2.1.2.3). D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-27 Design and Installation Specifications Sod shall be free of weeds, of uniform thickness (approximately 1-inch thick), and shall have a dense root mat for mechanical strength. The following steps are recommended for sod installation: 1. Shape and smooth the surface to final grade in accordance with the approved grading plan. 2. Amend four inches (minimum) of well-rotted compost into the top eight inches of the soil if the organic content of the soil is less than ten percent. Compost used shall meet compost specifications per SWDM Reference Section 11-C. 3. Fertilize according to the supplier’s recommendations. Disturbed areas within 200 feet of water bodies and wetlands must use non-phosphorus fertilizer. 4. Work lime and fertilizer 1 to 2 inches into the soil, and smooth the surface. 5. Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least 12 inches. Staple on slopes steeper than 3H:1V. 6. Roll the sodded area and irrigate. 7. When sodding is carried out in alternating strips or other patterns, seed the areas between the sod immediately after sodding. Maintenance Standards If the grass is unhealthy, the cause shall be determined and appropriate action taken to reestablish a healthy groundcover. If it is impossible to establish a healthy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. D.2.1.2.8 POLYACRYLAMIDE FOR SOIL EROSION PROTECTION Purpose Polyacrylamide (PAM) is used on construction sites to prevent soil erosion. Applying PAM to bare soil in advance of a rain event significantly reduces erosion and controls sediment in two ways. First, PAM increases the soil’s available pore volume, thus increasing infiltration through flocculation and reducing the quantity of stormwater runoff. Second, it increases flocculation of suspended particles and aids in their deposition, thus reducing stormwater runoff turbidity and improving water quality. Conditions of Use 1. PAM shall not be directly applied to water or allowed to enter a water body. 2. PAM may be applied to wet soil, but dry soil is preferred due to less sediment loss. 3. PAM will work when applied to saturated soil but is not as effective as applications to dry or damp soil. 4. PAM may be applied only to the following types of bare soil areas that drain to a sediment trap or a sediment pond: • Staging areas • Stockpiles • Pit sites • Balanced cut and fill earthwork • Haul roads prior to placement of crushed rock surfacing • Compacted soil road base SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-28 5. PAM may be applied only during the following phases of construction: • During rough grading operations • After final grade and before paving or final seeding and planting • During a winter shut down of site work. In the case of winter shut down, or where soil will remain unworked for several months, PAM should be used together with mulch. 6. Do not use PAM on a slope that flows directly to a stream or wetland. The stormwater runoff shall pass through a sediment control measure prior to discharging to surface waters. Design and Installation Specifications 1. PAM must be applied using one of two methods of application, “preferred” or “alternative.” The specifications for these methods are described under separate headings below. 2. PAM may be applied in dissolved form with water, or it may be applied in dry, granular or powdered form. The preferred application method is the dissolved form. 3. PAM is to be applied at a maximum rate of ½ pound PAM per 1000 gallons of water per 1 acre of bare soil. Table D.2.1.2.H may be used to determine the PAM and water application rate for disturbed soil areas. Higher concentrations of PAM do not provide any additional effectiveness. 4. Do not add PAM to water discharging from the site. 5. PAM shall be used in conjunction with other ESC measures and not in place of them. When the total drainage area is greater than or equal to 3 acres, PAM treated areas shall drain to a sediment pond per Section D.2.1.5.2. For drainage areas less than 3 acres, PAM treated areas must drain to a sediment trap per Section D.2.1.5.1. Other normally required sediment control measures such as perimeter protection measures (Section D.2.1.3) and surface water collection measures (Section D.2.1.6) shall be applied to PAM treated areas. 6. All areas not being actively worked shall be covered and protected from rainfall. PAM shall not be the only cover BMP used. 7. Keep the granular PAM supply out of the sun. Granular PAM loses its effectiveness in three months after exposure to sunlight and air. 8. Care must be taken to prevent spills of PAM powder onto paved surfaces. PAM, combined with water, is very slippery and can be a safety hazard. During an application of PAM, prevent over-spray from reaching pavement as the pavement will become slippery. If PAM powder gets on skin or clothing, wipe it off with a rough towel rather than washing with water. Washing with water only makes cleanup more difficult, messier, and time consuming. 9. The specific PAM copolymer formulation must be anionic. Cationic PAM shall not be used in any application because of known aquatic toxicity concerns. Only the highest drinking water grade PAM, certified for compliance with ANSI/NSF Standard 60 for drinking water treatment, may be used for soil applications. The Washington State Department of Transportation (WSDOT) lists approved PAM products on their web page. All PAM use shall be reviewed and approved by CED. 10. The PAM anionic charge density may vary from 2 to 30 percent; a value of 18 percent is typical. Studies conducted by the United States Department of Agriculture (USDA)/ARS demonstrated that soil stabilization was optimized by using very high molecular weight (12 to 15 mg/mole), highly anionic (>20% hydrolysis) PAM. 11. PAM must be “water soluble” or “linear” or “non-cross-linked.” Cross-linked or water absorbent PAM, polymerized in highly acidic (pH<2) conditions, are used to maintain soil moisture content. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-29 TABLE D.2.1.2.H PAM AND WATER APPLICATION RATES Disturbed Area (ac) PAM (lbs) Water (gal) 0.50 0.25 500 1.00 0.50 1,000 1.50 0.75 1,500 2.00 1.00 2,000 2.50 1.25 2,500 3.00 1.50 3,000 3.50 1.75 3,500 4.00 2.00 4,000 4.50 2.25 4,500 5.00 2.50 5,000 Preferred Application Method 1. Pre-measure the area where PAM is to be applied and calculate the amount of product and water necessary to provide coverage at the specified application rate (1/2 pound PAM/1,000 gallons/acre). 2. Dissolve pre-measured dry granular PAM with a known quantity of clean water in a bucket several hours or overnight. PAM has infinite solubility in water, but dissolves very slowly. Mechanical mixing will help dissolve PAM. Always add PAM to water – not water to PAM. 3. Pre-fill the water truck about 1/8 full with water. The water does not have to be potable, but it must have relatively low turbidity – in the range of 20 NTU or less. 4. Add PAM/Water mixture to the truck. 5. Completely fill the water truck to specified volume. 6. Spray PAM/Water mixture onto dry soil until the soil surface is uniformly and completely wetted. Alternate Application Method PAM may also be applied as a powder at the rate of 5 pounds per acre. This must be applied on a day that is dry. For areas less than 5 to 10 acres, a hand-held “organ grinder” fertilized spreader set to the smallest setting will work. Tractor mounted spreaders will work for larger areas. Maintenance Standards 1. PAM may be reapplied on actively worked areas after a 48-hour period 2. Reapplication is not required unless PAM treated soil is disturbed or unless turbidity levels show the need for an additional application. If PAM treated soil is left undisturbed, a reapplication may be necessary after two months. More PAM applications may be required for steep slopes, silty and clay soils, (USDA classification Type “C” and “D” soils), long grades, and high precipitation areas. When PAM is applied first to bare soil and then covered with straw, a reapplication may not be necessary for several months. D.2.1.2.9 COMPOST BLANKETS Code: COBL Symbol: Purpose Compost blankets are intended to: SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-30 • Provide immediate temporary protection from erosion by protecting soil from rainfall and slowing flow velocity over the soil surface. • Enhance temporary or permanent plant establishment by conserving moisture, holding seed and topsoil in place, providing nutrients and soil microorganisms, and moderating soil temperatures. • Compost blankets, applied at the proper thickness and tilled into the soil, are also an option for amending soils for permanent landscaping. • Compost generally releases and adds phosphorous to stormwater. Therefore, compost blankets are not recommended for use in watersheds where phosphorous sensitive water resources are located. Unless prior approval is given by the City, they should not be used in Sensitive Lake Watersheds. Conditions of Use 1. Compost blankets may be used unseeded on disturbed areas that require temporary cover measures up to 1 year. Compost applied as temporary cover may be reclaimed and re-used for permanent cover. 2. Compost provides cover for protecting final grades until landscaping can be completed as it can be directly seeded or tilled into soil as an amendment. 3. Compost blankets meet mulch requirements for seed. 4. Seed may be applied to a compost blanket at any time for permanent or temporary stabilization of disturbed areas. Seed may be applied prior to blanket application, on top of blankets, or injected and mixed into the compost as it is applied. 5. Compost blankets may be applied on slopes up to 2H:1V. Design and Installation Specifications 1. Compost shall be applied at a minimum of 2 inches thick, unless otherwise directed by an ESC supervisor or the City. At an application of 2 inches, this will equal approximately 100 tons per acre (compost generally weighs approximately 800 lbs per cubic yard). Thickness shall be increased at the direction of the design engineer for disturbed areas in or near critical areas or other areas highly susceptible to erosion. 2. Compost shall meet criteria in Reference Section 11-C of the SWDM. 3. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. 4. Compost blankets shall be applied over the top of the slope to which it is applied, to prevent water from running under the blanket 5. Compost blankets shall not be used in areas exposed to concentrated flow (e.g., channels, ditches, dikes) Maintenance Standards 1. The specified thickness of the blanket/cover must be maintained. 2. Any areas that show signs of erosion must be re-mulched. If the erosion problem is drainage related, then the drainage problem must first be remedied and then the eroded area re-mulched. D.2.1.3 PERIMETER PROTECTION Perimeter protection to filter sediment from sheetwash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Perimeter protection includes the use of vegetated strips as well as, constructed measures, such as silt fences, fiber rolls, sand/gravel barriers, brush or rock filters, triangular silt dikes and other methods. During the wet season, 50 linear feet of silt fence (and the necessary stakes) per acre of disturbed area must be stockpiled on site. Purpose: The purpose of perimeter protection is to reduce the amount of sediment transported beyond the disturbed areas of the construction site. Perimeter protection is primarily a backup means of sediment control. Most, if not all, sediment-laden water is to be treated in a sediment trap or pond. The only D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-31 circumstances in which perimeter control is to be used as a primary means of sediment removal is when the catchment is very small (see below). When to Install: Perimeter protection is to be installed prior to any upslope clearing and grading. Measures to Use: The above measures may be used interchangeably and are not the only perimeter protection measures available. If surface water is collected by an interceptor dike or swale and routed to a sediment pond or trap, there may be no need for the perimeter protection measures specified in this section. Criteria for Use as Primary Treatment: At the boundary of a site, perimeter protection may be used as the sole form of treatment when the flowpath meets the criteria listed below. If these criteria are not met, perimeter protection shall only be used as a backup to a sediment trap or pond. Average Slope Slope Percent Flowpath Length 1.5H:1V or less 67% or less 100 feet 2H:1V or less 50% or less 115 feet 4H:1V or less 25% or less 150 feet 6H:1V or less 16.7% or less 200 feet 10H:1V or less 10% or less 250 feet D.2.1.3.1 SILT FENCE Code: SF Symbol: Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Silt fence may be used downslope of all disturbed areas. 2. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a silt fence, rather than by a sediment trap or pond, is when the area draining to the fence is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3 above). Design and Installation Specifications 1. See Figure D.2.1.3.A and Figure D.2.1.3.B for details. 2. The geotextile used must meet the standards listed below. A copy of the manufacturer’s fabric specifications must be available on site. AOS (ASTM D4751) 30–100 sieve size (0.60–0.15 mm) for slit film 50–100 sieve size (0.30–0.15 mm) for other fabrics Water Permittivity (ASTM D4491) 0.02 sec-1 minimum Grab Tensile Strength (ASTM D4632) (see Specification Note 3) 180 lbs. min. for extra strength fabric 100 lbs. min. for standard strength fabric Grab Tensile Elongation (ASTM D4632) 30% max. (woven) Ultraviolet Resistance (ASTM D4355) 70% min. 3. Standard strength fabric requires wire backing to increase the strength of the fence. Wire backing or closer post spacing may be required for extra strength fabric if field performance warrants a stronger fence. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-32 4. Where the fence is installed, the slope shall be no steeper than 2H:1V. 5. If a typical silt fence (per Figure D.2.1.3.A) is used, the standard 4 x 4 trench may not be reduced as long as the bottom 8 inches of the silt fence is well buried and secured in a trench that stabilizes the fence and does not allow water to bypass or undermine the silt fence. Maintenance Standards 1. Any damage shall be repaired immediately. 2. If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment trap or pond. 3. It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. 4. Sediment must be removed when the sediment is 6 inches high. 5. If the filter fabric (geotextile) has deteriorated due to ultraviolet breakdown, it shall be replaced. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-33 FIGURE D.2.1.3.A SILT FENCE 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED NOTE: FILTER FABRIC FENCESSHALL BE INSTALLED ALONGCONTOURS WHENEVER POSSIBLE JOINTS IN FILTER FABRIC SHALL BE SPLICEDAT POSTS. USE STAPLES, WIRE RINGS OREQUIVALENT TO ATTACH FABRIC TO POSTS. FILTER FABRIC BACKFILL TRENCH WITH NATIVE SOIL OR 3/4" TO 1-1/2" WASHED GRAVEL MINIMUM 4"x4" TRENCH 2"x4" WOOD POSTS, STEEL FENCEPOSTS, REBAR, OR EQUIVALENT POST SPACING MAY BEINCREASED TO 8' IFWIRE BACKING IS USED 6' MAX.2' MIN.12" MIN. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-34 FIGURE D.2.1.3.B SILT FENCE INSTALLATION BY SLICING 1.GATHER FABRIC AT POSTS, IF NEEDED. 2.UTILIZE THREE TIES PER POST, ALLWITHIN TOP 8" OF FABRIC. 3.POSITION EACH TIE DIAGONALLY,PUNCTURING HOLES VERTICALLY A MINIMUM OF 1" APART. 4.HANG EACH TIE ON A POST NIPPLE ANDTIGHTEN SECURELY. USE CABLE TIES (50 LBS) OF SOFT WIRE. TOP OF FABRIC BELT DIAGONAL ATTACHMENTDOUBLES STRENGTH FLOW STEEL SUPPORT POST1.POST SPACING: 7' MAX. ON OPEN RUNS4' MAX. ON POOLING AREAS. 2.POST DEPTH: AS MUCH BELOW GROUND AS FABRIC ABOVE GROUND. 3.PONDING HEIGHT MAX. 24" ATTACH FABRIC TO UPSTREAM SIDE OF POST. 4.DRIVE OVER EACH SIDE OF SILT FENCE 2 TO 4 TIMES WITH DEVICE EXERTING 60 P.S.I. OR GREATER. 5.NO MORE THAN 24" OF A 36" FABRIC IS ALLOWED ABOVE GROUND. 6.VIBRATORY PLOW IS NOT ACCEPTABLEBECAUSE OF HORIZONTAL COMPACTION. 100% COMPACTIONEACH SIDE OPERATION ROLL OF SILT FENCE PLOW FABRIC ABOVEGROUND HORIZONTAL CHISEL POINT (76 mm WIDTH)200-300mm SILT FENCE TOP 8" NOTES: ATTACHMENT DETAILS: SILT FENCE INSTALLATION BY SLICING METHODNTS D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-35 D.2.1.3.2 BRUSH BARRIER Code: BB Symbol: Purpose The purpose of brush barriers is to reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Brush barriers may be used downslope of all disturbed areas. 2. Brush barriers are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a barrier, rather than by a sediment trap or pond, is when the area draining to the barrier is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3). Design and Installation Specifications 1. See Figure D.2.1.3.C for details. 2. The City may require filter fabric (geotextile) anchored over the brush berm to enhance the filtration ability of the barrier. Maintenance Standards 1. There shall be no signs of erosion or concentrated runoff under or around the barrier. If concentrated flows are bypassing the barrier, it must be expanded or augmented by toed-in filter fabric. 2. The dimensions of the barrier must be maintained. FIGURE D.2.1.3.C BRUSH BARRIER IF REQUIRED, DRAPE FILTER FABRICOVER BRUSH AND SECURE IN 4"x4"MIN. TRENCH WITH COMPACTEDBACKFILL MAX. 6" DIAMETER WOODY DEBRIS FOR BARRIER CORE. ALTERNATIVELY TOPSOIL STRIPPINGS MAY BE USED TO FORM THE BARRIER. ANCHOR DOWNHILL EDGE OFFILTER FABRIC WITH STAKES,SANDBAGS, OR EQUIVALENT 2' MIN. HEIGHT 5' MIN. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-36 D.2.1.3.3 VEGETATED STRIP Code: VS Symbol: Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Vegetated strips may be used downslope of all disturbed areas. 2. Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a strip, rather than by a sediment trap or pond, is when the area draining to the strip is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3). Design and Installation Specifications 1. The vegetated strip shall consist of a 25-foot minimum width continuous strip of dense vegetation with a permeable topsoil. Grass-covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff. 2. The slope within the strip shall not exceed 4H:1V. 3. The uphill boundary of the vegetated strip shall be delineated with clearing limits as specified in Section D.2.1.1. Maintenance Standards 1. Any areas damaged by erosion or construction activity shall be seeded immediately and protected by mulch. 2. If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed using the standards for installation found in Section D.2.1.2.7. If there are indications that concentrated flows are traveling across the buffer, surface water controls must be installed to reduce the flows entering the buffer, or additional perimeter protection must be installed. D.2.1.3.4 TRIANGULAR SILT DIKE (GEOTEXTILE ENCASED CHECK DAM) Code: TSD Symbol: Purpose Triangular silt dikes (TSDs) may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Silt dikes, if attached to impervious surfaces with tack or other adhesive agent may also be used as temporary wheel wash areas, or concrete washout collection areas. Conditions of Use 1. May be used for temporary check dams in ditches. 2. May be used on soil or pavement with adhesive or staples. 3. TSDs have been used to build temporary sediment ponds, diversion ditches, concrete washout facilities, curbing, water bars, level spreaders, and berms. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-37 Design and Installation Specifications 1. TSDs must be made of urethane foam sewn into a woven geosynthetic fabric. 2. TSDs are triangular, 10 inches to 14 inches high in the center, with a 20-inch to 28-inch base. A 2-foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed 3. Install TSDs with ends curved up to prevent water from flowing around the ends 4. Attach the TSDs and their fabric flaps to the ground with wire staples. Wire staples must be No. 11 gauge wire or stronger and shall be 200 mm to 300 mm in length. 5. When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. 6. TSDs must be located and installed as soon as construction will allow. 7. TSDs must be placed perpendicular to the flow of water. 8. When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. 9. When used in grass-lined ditches and swales, the TSD check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the TSD check dams shall be seeded and mulched immediately after dam removal. Maintenance Standards 1. Triangular silt dikes shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall event. Sediment shall be removed when it reaches one half the height of the silt dike. 2. Anticipate submergence and deposition above the triangular silt dike and erosion from high flows around the edges of the dike/dam. Immediately repair any damage or any undercutting of the dike/dam. D.2.1.3.5 COMPOST BERMS Code: COBE Symbol: Purpose Compost berms are an option to meet the requirements of perimeter protection. Compost berms may reduce the transport of sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Compost berms trap sediment by filtering water passing through the berm and allowing water to pond, creating a settling area for solids behind the berm. Organic materials in the compost can also reduce concentrations of metals and petroleum hydrocarbons from construction runoff. Due to the increase in phosphorous seen in the effluent data from compost berms, they should be used with some cautions in areas that drain to phosphorus sensitive water bodies, and should only be used in Sensitive Lake watersheds, such as Lake Sammamish, with the approval from the City or the local jurisdiction. Conditions of Use 1. Compost berms may be used in most areas requiring sediment or erosion control where runoff is in the form of sheet flow or in areas where silt fence is normally considered acceptable. Compost berms may be used in areas where migration of aquatic life such as turtles and salamanders are impeded by the use of silt fence. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-38 2. Compost berms are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed via a drainage system to a sediment pond or trap. 3. For purposes of long-term sediment control objectives, berms may be seeded at the time of installation to create an additional vegetated filtering component. Design and Installation Specifications 1. Compost berms shall be applied using a pneumatic blower device or equivalent, to produce a uniform cross-section and berm density. 2. Compost berms shall be triangular in cross-section. The ratio of base to height dimensions shall be 2:1. 3. The minimum size of a compost berm is a 2-foot base with a 1-foot height. 4. Compost berms shall be sized and spaced as indicated in the table below. SLOPE SLOPE Maximum Slope Length or Berm Spacing (linear feet) Berm Size Required (height x base width) 0% – 2% Flatter than 50:1 250 1 ft x 2 ft 2% – 10% 50:1 – 10:1 125 1 ft x 2 ft 10% – 20% 10:1 – 5:1 100 1 ft x 2 ft 20% – 33% 5:1 – 3:1 75 1 ft x 2 ft 33% – 50% 3:1 – 2:1 50 1.5 ft x 3 ft 5. Compost berms shall not be used on slopes greater than 2H:1V. 6. Compost shall meet criteria in Reference Section 11-C of the SWDM except for the particle size distribution (see Bullet 8). 7. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. 8. Compost particle size distribution shall be as follows: 99% passing a 1 inch sieve, 90% passing a 3/4-inch sieve and a minimum of 70% greater than the 3/8-inch sieve. A total of 98% shall not exceed 3 inches in length. 9. Berms shall be placed on level contours to assist in dissipating flow into sheet flow rather than concentrated flows. Berms shall not be constructed to concentrate runoff or channel water. Sheet flow of water shall be perpendicular to the berm at impact. No concentrated flow shall be directed towards compost berms. 10. Where possible, berms shall be placed 5 feet or more from the toe of slopes to allow space for sediment deposition and collection. 11. In order to prevent water from flowing around the ends of the berms, the ends of the berm shall be constructed pointing upslope so the ends are at a higher elevation than the rest of the berm. 12. A compost blanket extending 10 to 15 feet above the berm is recommended where the surface above the berm is rutted or uneven, to reduce concentrated flow and promote sheet flow into the berm. Maintenance Standards 1. Compost berms shall be regularly inspected to make sure they retain their shape and allow adequate flow-through of stormwater. 2. When construction is completed on site, the berms shall be dispersed for incorporation into the soil or left on top of the site for final seeding to occur. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-39 3. Any damage to berms must be repaired immediately. Damage includes flattening, compacting, rills, eroded areas due to overtopping. 4. If concentrated flows are evident uphill of the berm, the flows must be intercepted and conveyed to a sediment trap or pond. 5. The uphill side of the berm shall be inspected for signs of the berm clogging and acting as a barrier to flows and causing channelization of flows parallel to the berm. If this occurs, replace the berm or remove the trapped sediment. 6. Sediment that collects behind the berm must be removed when the sediment is more than 6 inches deep. D.2.1.3.6 COMPOST SOCKS Code: COSO Symbol: Purpose Compost socks reduce the transport of sediment from a construction site by providing a temporary physical barrier to sediment-laden water and reducing the runoff velocities of overland flow. Compost socks trap sediment by filtering water that passes through the sock and allows water to pond behind the sock, creating a settling area for solids. Organic materials in the compost also may reduce metal and petroleum hydrocarbon concentrations in construction runoff. Compost socks function similarly to compost berms; however, because the compost is contained in a mesh tube, they are appropriate for both concentrated flow and sheet flow. Compost socks may be used to channel concentrated flow on hard surfaces. Conditions of Use 1. Compost socks may be used in areas requiring sediment or erosion control where runoff is in the form of sheet flow or in areas that silt fence is normally considered acceptable. Compost socks may also be used in sensitive environmental areas where migration of aquatic life, including turtles, salamanders and other aquatic life may be impeded by the used of silt fence. 2. Compost socks are not intended to treat substantial amounts of overland flow. However, compost socks may be subjected to some ponding and concentrated flows. If intended primarily as a filtration device, the socks should be sized and placed so that flows do not overtop the socks. 3. For purposes of long term sediment control objectives, compost socks may be seeded at the time of installation to create an additional vegetated filtering component. Design and Installation Specifications 1. Compost socks shall be produced using a pneumatic blower hose or equivalent to fill a mesh tube with compost to create a uniform cross-section and berm density. 2. Socks shall be filled so they are firmly – packed yet flexible. Upon initial filling, the socks shall be filled to have a round cross-section. Once placed on the ground, it is recommended to apply weight to the sock to improve contact with the underlying surface. This may cause the sock to assume an oval shape. 3. Compost socks shall be a minimum of 8 inches in diameter. Larger diameter socks are recommended for areas where ponding is expected behind the sock. 4. Compost socks shall not be used on slopes greater than 2H:1V. 5. Compost shall meet criteria in Reference Section 11-C of the SWDM, except for the particle size distribution (see Bullet 7). 6. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-40 7. Compost particle size distribution shall be as follows: 99% passing a 1-inch sieve, 90% passing a 3/4-inch sieve and a minimum of 70% greater than the 3/8-inch sieve. A total of 98% shall not exceed 3 inches in length. 8. In order to prevent water from flowing around the ends of compost socks, the ends must be pointed upslope so the ends of the socks are at a higher elevation than the remainder of the sock. Maintenance Standards 1. Compost socks shall be regularly inspected to make sure the mesh tube remains undamaged, the socks retain their shape, and allow adequate flow through of surface water. If the mesh tube is torn, it shall be repaired using twine, zip-ties, or wire. Large sections of damaged socks must be replaced. Any damage must be repaired immediately upon discovery of damage. 2. When the sock is no longer needed, the socks shall be cut open and the compost dispersed to be incorporated into the soil or left on top of the soil for final seeding to occur. The mesh material must be disposed of properly as solid waste. If spills of oil, antifreeze, hydraulic fluid, or other equipment fluids have occurred that have saturated the sock, the compost must be disposed of properly as a waste. 3. Sediment must be removed when sediment accumulations are within 3 inches of the top of the sock. D.2.1.4 TRAFFIC AREA STABILIZATION Unsurfaced entrances, roads, and parking areas used by construction traffic shall be stabilized to minimize erosion and tracking of sediment off site. Stabilized construction entrances shall be installed as the first step in clearing and grading. At the City’s discretion, road and parking area stabilization is not required during the dry season (unless dust is a concern) or if the site is underlain by coarse-grained soils. Roads and parking areas shall be stabilized immediately after initial grading. Purpose: The purpose of traffic area stabilization is to reduce the amount of sediment transported off site by construction vehicles and to reduce the erosion of areas disturbed by vehicle traffic. Sediment transported off site onto paved streets is a significant problem because it is difficult to effectively remove, and any sediment not removed ends up in the drainage system. Additionally, sediment on public right-of-way can pose a serious traffic hazard. Construction road and parking area stabilization is important because the combination of wet soil and heavy equipment traffic typically forms a slurry of easily erodible mud. Finally, stabilization also is an excellent form of dust control in the summer months. When to Install: The construction entrance is to be installed as the first step in clearing and grading. Construction road stabilization shall occur immediately after initial grading of the construction roads and parking areas. Measures to Use: There are two types of traffic area stabilization: (1) a stabilized construction entrance and (2) construction road/parking area stabilization. Both measures must be used as specified under “Conditions of Use” for each measure. D.2.1.4.1 STABILIZED CONSTRUCTION ENTRANCE Code: CE Symbol: Purpose Construction entrances are stabilized to reduce the amount of sediment transported onto paved roads by motor vehicles or runoff by constructing a stabilized pad of quarry spalls at entrances to construction sites. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-41 Conditions of Use Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within 1,000 feet of the site. Access and exits shall be limited to one route if possible, or two for linear projects such as roadway where more than one access/exit is necessary for maneuvering large equipment. For residential construction provide stabilized construction entrances for each residence in addition to the main subdivision entrance. Stabilized surfaces shall be of sufficient length/width to provide vehicle access/parking, based on lot size/configuration. Design and Installation Specifications 1. See Figure D.2.1.4.A for details. 2. A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4632) 200 lbs min. Grab Tensile Elongation (ASTM D4632) 30% max.(woven) Puncture Strength (ASTM D6241) 495 lbs min. AOS (ASTM D4751) 20–45 (U.S. standard sieve size) 3. Do not use crushed concrete, cement, or calcium chloride for construction entrance stabilization because these products raise pH levels in stormwater and concrete discharge to surface waters of the State is prohibited. 4. Hog fuel (wood based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. The effectiveness of hog fuel is highly variable, but it has been used successfully on many sites. It generally requires more maintenance than quarry spalls. Hog fuel is not recommended for entrance stabilization in urban areas. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause difficulties with compaction. 5. Fencing (see Section D.2.1.1) shall be installed as necessary to restrict traffic to the construction entrance. 6. Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance Standards 1. Quarry spalls (or hog fuel) shall be added if the pad is no longer in accordance with the specifications. 2. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. If washing is used, it shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. 3. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled. Wash water must be pumped back onto the site and cannot discharge to systems tributary to surface waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-42 4. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. 5. If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see Section D.2.1.1) shall be installed to control traffic. FIGURE D.2.1.4.A SCHEMATIC REPRESENTATION OF A STABILIZED CONSTRUCTION ENTRANCE D.2.1.4.2 CONSTRUCTION ROAD/PARKING AREA STABILIZATION Code: CRS Symbol: Purpose Stabilizing subdivision roads, parking areas and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use 1. Roads or parking areas shall be stabilized wherever they are constructed, whether permanent or temporary, for use by construction traffic. 2. Fencing (see Section D.2.1.1) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and Installation Specifications 1. A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or •PER KING COUNTY ROAD DESIGN AND CONSTRUCTION STANDARDS (KCRDCS), DRIVEWAYS SHALL BE PAVED TO EDGE OF R-O-W PRIOR TO INSTALLATION OF THE CONSTRUCTION ENTRANCE TOAVOID DAMAGING OF THE ROADWAY. •IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD. 12" MIN. THICKNESS PROVIDE FULL WIDTH OFINGRESS/EGRESS AREA IF A ROADSIDE DITCH ISPRESENT, INSTALL DRIVEWAY CULVERT PER KCRDCS GEOTEXTILE 4"- 8" QUARRYSPALLS R=25' MIN. 100' M I N . EXISTI N G R O A D 15' MI N. NOTES: D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-43 calcium chloride for soil stabilization. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. Note: If the area will be used for permanent road or parking installation later in the project, the subgrade will be subject to inspection. 2. Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain transversely. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super-elevated section. Drainage ditches shall be designed in accordance with the standards given in Section D.2.1.6.4 and directed to a sediment pond or trap. 3. Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet-flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include vegetated wetlands. If runoff is allowed to sheet flow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. 4. In order to control construction traffic, the City may require that signs be erected on site informing construction personnel that vehicles, other than those performing clearing and grading, are restricted to stabilized areas. 5. If construction roads do not adequately reduce trackout to adjacent property or roadways, a wheel wash system will be required. Maintenance Standards Crushed rock, gravel base, hog fuel, etc., shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. D.2.1.4.3 WHEEL WASH Code: WW Symbol: Purpose Wheel wash systems reduce the amount of sediment transported onto paved roadways and into surface water systems by construction vehicles. Conditions of Use When a stabilized construction entrance is not preventing sediment from being tracked onto pavement: • Wheel washing is generally an effective erosion and sediment control method and BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck wheels and undercarriage can run unimpeded into the street. • Pressure washing combined with an adequately sized and properly surfaced wash pad with direct drainage discharge to a large 10-foot x 10-foot sump can be very effective. Design and Installation Specifications A suggested detail is shown in Figure D.2.1.4.B. 1. A minimum of 6 inches of asphalt treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash area. 2. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will work well to test clearance. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-44 3. Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the truck tongues with water. 4. Midpoint spray nozzles are only needed in very muddy conditions. 5. Wheel wash systems should be designed with a small grade change, 6 to 12 inches for a 10-foot-wide pond, to allow sediment to flow to the low side of the pond and to help prevent re-suspension of sediment. 6. A drainpipe with a 2- to 3-foot riser should be installed on the low side of the wheel wash pond to allow for easy cleaning and refilling. Polymers may be used to promote coagulation and flocculation in a closed-loop system. 7. Polyacrylamide (PAM) added to the wheel washwater at a rate of 0.25 to 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water truck, the same truck may be used to change the washwater. Maintenance Standards 1. The wheel wash should start out each day with clean, fresh water. 2. The washwater should be changed a minimum of once per day. On large earthwork jobs where more than 10 to 20 trucks per hour are expected, the washwater will need to be changed more often. 3. Wheel wash or tire bath wastewater shall be discharged to a separate onsite treatment system, such as a closed-loop recirculation system or land application, or to the sanitary sewer system with proper approval and/or permits from King County and the City of Renton. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-45 FIGURE D.2.1.4.B WHEEL WASH AND PAVED CONSTRUCTION ENTRANCE 2%SLOPE 15'15'20'15'50' 18' 12' 3' 5' BUILD 8'x8' SUMP TO ACCOMODATE CLEANING BY TRACKHOE.SECTION A-A NTS 8'x8' SUMP, SEE NOTE LOCATE INVERT OF TOP PIPE 1' ABOVE BOTTOM OF WHEEL WASH DRAIN PIPE 1:1 SLOPE WATER LEVEL ELEVATION VIEW NTS PLAN VIEWNTS 6" SLEEVE CURB ASPHALT CURB ON THELOW ROAD SIDE TO DIRECTWATER BACK TO POND 6" ATB CONSTRUCTIONENTRANCE 1-1/2" SCHEDULE 40FOR SPRAYERS 2% SLOPE MIDPOINT SPRAYNOZZLES, IF NEEDED 3" TRASH PUMP WITH FLOATS ON SUCTION HOSE 2" SCHEDULE 40 6" SLEEVE UNDER ROAD 8'x8' SUMP WITH 5'OF CATCH 6" SEWER PIPE WITH BUTTERFLY VALVES 1:1 SLOPE A A 5:1SLOPE5:1SLOPE 15' ATB APRON TO PROTECTGROUND FROM SPLASHING WATER BALL VALVES NOTE: SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-46 D.2.1.5 SEDIMENT RETENTION Surface water collected from disturbed areas of the site shall be routed through a sediment pond or trap prior to release from the site. An exception is for areas at the perimeter of the site with drainage areas small enough to be treated solely with perimeter protection (see Section D.2.1.3). Also, if the soils and topography are such that no offsite discharge of surface water is anticipated up to and including the developed 2-year runoff event, sediment ponds and traps are not required. A 10-year peak flow using the approved model with 15-minute time steps shall be used for sediment pond/trap sizing if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection (see below). At the City’s discretion, sites may be worked during the dry season without sediment ponds and traps if there is some other form of protection of surface waters, such as a 100-foot forested buffer between the disturbed areas and adjacent surface waters. For small sites, use the criteria defined in Section D.2.1.3, Perimeter Protection to determine minimum flow path length. If the site work has to be extended into the wet season, a back-up plan must be identified in the CSWPP plan and implemented. Protection of catch basins is required for inlets that are likely to be impacted by sediment generated by the project and that do not drain to an onsite sediment pond or trap. Sediment retention facilities shall be installed prior to grading of any contributing area and shall be located so as to avoid interference with the movement of juvenile salmonids attempting to enter off-channel areas or drainages. Purpose: The purpose of sediment retention facilities is to remove sediment from runoff generated from disturbed areas. When to Install: The facilities shall be constructed as the first step in the clearing and grading of the site. The surface water conveyances may then be connected to the facilities as site development proceeds. Measures to Use: There are three sediment retention measures in this section. The first two, sediment traps and ponds, serve the same function but for different size catchments. All runoff from disturbed areas must be routed through a trap or pond except for very small areas at the perimeter of the site small enough to be treated solely with perimeter protection (see Section D.2.1.3). The third measure is for catch basin protection. It is only to be used in limited circumstances and is not a primary sediment treatment facility. It is only intended as a backup in the event of failure of other onsite systems. Use of Permanent Drainage Facilities: All projects that are constructing permanent facilities for runoff quantity control are strongly encouraged to use the rough-graded or final-graded permanent facilities for ponds and traps. This includes combined facilities and infiltration facilities. When permanent facilities are used as temporary sedimentation facilities, the surface area requirements of sediment traps (for drainages less than 3 acres) or sediment ponds (more than 3 acres) must be met. If the surface area requirements are larger than the surface area of the permanent facility, then the pond shall be enlarged to comply with the surface area requirement. The permanent pond shall also be divided into two cells as required for sediment ponds. Either a permanent control structure or the temporary control structure described in Section D.2.1.5.2 may be used. If a permanent control structure is used, it may be advisable to partially restrict the lower orifice with gravel to increase residence time while still allowing dewatering of the pond. If infiltration facilities are to be used, the sides and bottom of the facility must only be rough excavated to a minimum of three feet above final grade. Excavation should be done with a backhoe working at “arm’s length” to minimize disturbance and compaction of the infiltration surface. Additionally, any required pretreatment facilities shall be fully constructed prior to any release of sediment-laden water to the facility. Pretreatment and shallow excavation are intended to prevent the clogging of soil with fines. Final grading of the infiltration facility shall occur only when all contributing drainage areas are fully stabilized (see Section D.2.4.5). Selection of the Design Storm: In most circumstances, the developed condition 2-year peak flow using the approved model with 15-minute time steps is sufficient for calculating surface area for ponds and traps and for determining exemptions from the sediment retention and surface water collection requirements (Sections D.2.1.5 and D.2.1.6, respectively). In some circumstances, however, the approved model 10-year 15-minute peak flow should be used. Examples of such circumstances include the following: D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-47 • Sites that are within ¼ mile of salmonid streams, wetlands, and designated sensitive lakes such as Lake Sammamish • Sites where significant clearing and grading is likely to occur during the wet season • Sites with downstream erosion or sedimentation problems. Natural Vegetation: Whenever possible, sediment-laden water shall be discharged into onsite, relatively level, vegetated areas. This is the only way to effectively remove fine particles from runoff. This can be particularly useful after initial treatment in a sediment retention facility. The areas of release must be evaluated on a site-by-site basis in order to determine appropriate locations for and methods of releasing runoff. Vegetated wetlands shall not be used for this purpose. Frequently, it may be possible to pump water from the collection point at the downhill end of the site to an upslope vegetated area. Pumping shall only augment the treatment system, not replace it because of the possibility of pump failure or runoff volume in excess of pump capacity. D.2.1.5.1 SEDIMENT TRAP Code: ST Symbol: Purpose Sediment traps remove sediment from runoff originating from disturbed areas of the site. Sediment traps are typically designed to only remove sediment as small as medium silt (0.02 mm). As a consequence, they usually only result in a small reduction in turbidity. Conditions of Use A sediment trap shall be used where the contributing drainage area is 3 acres or less. Design and Installation Specifications 1. See Figure D.2.1.5.A for details. 2. If permanent runoff control facilities are part of the project, they should be used for sediment retention (see “Use of Permanent Drainage Facilities” in Section D.2.1.5). 3. To determine the trap geometry, first calculate the design surface area (SA) of the trap, measured at the invert of the weir. Use the following equation: SA = FS(Q2/Vs) where Q2 = Design inflow (cfs) from the contributing drainage area based on the developed condition 2-year or 10-year peak discharge using the approved model with 15-minute time steps as computed in the hydrologic analysis. The approved model 10-year 15-minute peak flow shall be used if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection, or if the pond discharge path leaves the site (note provisions must made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction, see Section D.3.9, Flow Control). If no hydrologic analysis is required, the Rational Method may be used (Section 3.2.1 of the SWDM). Vs = The settling velocity (ft/sec) of the soil particle of interest. The 0.02 mm (medium silt) particle with an assumed density of 2.65 g/cm3 has been selected as the particle of interest and has a settling velocity (Vs) of 0.00096 ft/sec. FS = A safety factor of 2 to account for non-ideal settling. Therefore, the equation for computing surface area becomes: SA = 2 x Q2/0.00096 or 2080 square feet per cfs of inflow SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-48 Note: Even if permanent facilities are used, they must still have a surface area that is at least as large as that derived from the above formula. If they do not, the pond must be enlarged. 4. To aid in determining sediment depth, all traps shall have a staff gage with a prominent mark one foot above the bottom of the trap. Maintenance Standards 1. Sediment shall be removed from the trap when it reaches 1 foot in depth. 2. Any damage to the trap embankments or slopes shall be repaired. FIGURE D.2.1.5.A SEDIMENT TRAP NOTE:TRAP MAY BE FORMED BY BERM OR BY PARTIAL OR COMPLETE EXCAVATION 3 H : 1 V M A X . FLAT BOTTOM 1' MIN. 18" MIN. 1' MIN. 1' MIN. DEPTH OVERFLOW SPILLWAY CROSS SECTION TRAP OUTLET NATIVE SOIL OR COMPACTEDBACKFILL GEOTEXTILE 6' MIN. MIN.1' DEPTH 2"-4" ROCK MIN. 1' DEPTH 3/4"-1 1/2"WASHED GRAVEL 4' MIN. 3.5'-5' SURFACE AREA DETERMINEDAT TOP OF WEIR DISCHARGE TO STABILIZED CONVEYANCE,OUTLET OR LEVEL SPREADER 3/4"-1 1/2" WASHED GRAVEL GEOTEXTILE 2"-4" ROCK RIPRAP 1' MIN. OVERFLOW D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-49 D.2.1.5.2 SEDIMENT POND Code: SP Symbol: Purpose Sediment ponds remove sediment from runoff originating from disturbed areas of the site. Sediment ponds are typically designed to only remove sediment as small as medium silt (0.02 mm). As a consequence, they usually reduce turbidity only slightly. Conditions of Use A sediment pond shall be used where the contributing drainage area is 3 acres or more. Design and Installation Specifications 1. See Figure D.2.1.5.B, Figure D.2.1.5.C, and Figure D.2.1.5.D for details. 2. If permanent runoff control facilities are part of the project, they should be used for sediment retention (see “Use of Permanent Drainage Facilities” in Section D.2.1.5). Determining Pond Geometry 1. Obtain the discharge from the hydrologic calculations for the 2-year and 10-year peak flows using the approved model with 15-minute time steps (Q2 and Q10). The approved model 10-year 15-minute peak flow shall be used if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection, or if the pond discharge path leaves the site (note provisions must made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction, see Section D.3.9, Flow Control). If no hydrologic analysis is required, the Rational Method may be used (Section 3.2.1 of the SWDM). 2. Determine the required surface area at the top of the riser pipe with the equation: SA = 2 x Q10/0.00096 or 2080 square feet per cfs of inflow See Section D.2.1.5.1 for more information on the derivation of the surface area calculation. 3. The basic geometry of the pond can now be determined using the following design criteria: • Required surface area SA (from Step 2 above) at top of riser • Minimum 3.5-foot depth from top of riser to bottom of pond • Maximum 3:1 interior side slopes and maximum 2:1 exterior slopes. The interior slopes may be increased to a maximum of 2:1 if fencing is provided at or above the maximum water surface • One foot of freeboard between the top of the riser and the crest of the emergency spillway • Flat bottom • Minimum one foot deep spillway • Length-to-width ratio between 3:1 and 6:1. Sizing of Discharge Mechanisms Principal Spillway: Determine the required diameter for the principal spillway (riser pipe). The diameter shall be the minimum necessary to pass the developed condition 10-year peak flow using the approved model with 15-minute time steps (Q10). Use Figure 5.1.4.H (SWDM Chapter 5) to determine this diameter (h = one foot). Note: A permanent control structure may be used instead of a temporary riser. Emergency Overflow Spillway: Determine the required size and design of the emergency overflow spillway for the developed condition 100-year approved model 15-minute peak flow using the procedure in Section 5.1.1 (“Emergency Overflow Spillway” subsection) of the SWDM. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-50 Dewatering Orifice: Determine the size of the dewatering orifice(s) (minimum 1-inch diameter) using a modified version of the discharge equation for a vertical orifice and a basic equation for the area of a circular orifice. 1. Determine the required area of the orifice with the following equation: hATg hAA sso)10(81.43600x6.0 )2(65.0 5.0 −== where Ao = orifice area (square feet) As = pond surface area (square feet) h = head of water above orifice (height of riser in feet) T = dewatering time (24 hours) g = acceleration of gravity (32.2 feet/second2) 2. Convert the required surface area to the required diameter D (inches) of the orifice: ooAADx54.13x24==π 3. The vertical, perforated tubing connected to the dewatering orifice must be at least 2 inches larger in diameter than the orifice to improve flow characteristics. The size and number of perforations in the tubing should be large enough so that the tubing does not restrict flow. The flow rate should be controlled by the orifice. Additional Design Specifications • The pond shall be divided into two roughly equal volume cells by a permeable divider that will reduce turbulence while allowing movement of water between cells. The divider shall be at least one-half the height of the riser and a minimum of one foot below the top of the riser. Wire-backed, 2- to 3-foot high, extra strength filter fabric (see Section D.2.1.3.1) supported by treated 4″ x 4″s may be used as a divider. Alternatively, staked straw bales wrapped with filter fabric (geotextile) may be used. • If the pond is more than 6 feet deep, a different mechanism must be proposed. A riprap embankment is one acceptable method of separation for deeper ponds. Other designs that satisfy the intent of this provision are allowed as long as the divider is permeable, structurally sound, and designed to prevent erosion under or around the barrier. • To aid in determining sediment depth, one-foot intervals shall be prominently marked on the riser. • If an embankment of more than 6 feet is proposed, the pond must comply with the criteria under “Embankments” in Section 5.1.1 of the Surface Water Design Manual. Maintenance Standards 1. Sediment shall be removed from the pond when it reaches 1 foot in depth. 2. Any damage to the pond embankments or slopes shall be repaired. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-51 FIGURE D.2.1.5.B SEDIMENT POND PLAN VIEW FIGURE D.2.1.5.C SEDIMENT POND CROSS SECTION INFLOW NOTE:POND MAY BE FORMED BY BERM OR BY PARTIAL OR COMPLETE EXCAVATION DISCHARGE TO STABILIZED CONVEYANCE,OUTLET OR LEVELSPREADER EMERGENCYOVERFLOW SPILLWAY KEY DIVIDER INTO SLOPE TO PREVENT FLOW AROUND SIDES THE POND LENGTH SHALL BE 3 TO 6 TIMES THEMAXIMUM POND WIDTH SILT FENCE OREQUIVALENTDIVIDER RISERPIPE POND LENGTH 3H : 1 V M A X . RISER PIPE (PRINCIPALSPILLWAY) OPEN AT TOP WITHTRASH RACK PER FIG. 5.1.1.C DEWATERING DEVICE (SEERISER DETAIL)2 H : 1 VMA X .3H:1VMAX.WIRE-BACKED SILTFENCE, STAKED STRAW BALES WRAPPED WITHFILTER FABRIC, OR EQUIVALENT DIVIDER CONCRETE BASE (SEE RISER DETAIL) DISCHARGE TO STABILIZEDCONVEYANCE, OUTLET OR LEVEL SPREADER DEWATERINGORIFICE CREST OFEMERGENCY SPILLWAY 1' 6' MIN. BERM WIDTH EMBANKMENT COMPACTED 95%MODIFIED PROCTOR. PERVIOUS MATERIALSSUCH AS GRAVEL OR CLEAN SAND SHALLNOT BE USED. 1' MIN. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-52 FIGURE D.2.1.5.D SEDIMENT POND RISER DETAIL D.2.1.5.3 STORM DRAIN INLET PROTECTION Code: FFP or CBI or CBP Symbol: or or Purpose Storm drain inlets are protected to prevent coarse sediment from entering storm drainage systems. Temporary devices around storm drains assist in improving the quality of water discharged to inlets or catch basins by ponding sediment-laden water. These devices are effective only for relatively small drainage areas. Conditions of Use 1. Protection shall be provided for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. 2. Inlet protection may be used anywhere at the applicant’s discretion to protect the drainage system. This will, however, require more maintenance, and it is highly likely that the drainage system will still require some cleaning. 3. The contributing drainage area must not be larger than one acre. Design and Installation Specifications 1. There are many options for protecting storm drain inlets. Two commonly used options are filter fabric protection and catch basin inserts. Filter fabric protection (see Figure D.2.1.5.E) is filter fabric (geotextile) placed over the grate. This method is generally very ineffective and requires intense maintenance efforts. Catch basin inserts (see Figure D.2.1.5.F) are manufactured devices that nest inside a catch basin. This method also requires a high frequency of maintenance to be effective. Both options provide adequate protection, but filter fabric is likely to result in ponding of water above the 3.5' MIN. 18" MIN. 2X RISER DIA. MIN. CORRUGATEDMETAL RISER CONCRETE BASE ALTERNATIVELY, METAL STAKES AND WIRE MAYBE USED TO PREVENTFLOTATION DEWATERING ORIFICE,SCHEDULE 40 STEELSTUB MIN. DIAMETER AS PER CALCULATIONS 6" MIN. PROVIDEADEQUATESTRAPPING POLYETHYLENE CAP PERFORATEDDEWATERING DEVICE,SEE NOTE WATERTIGHTCOUPLING TACKWELD NOTE:PERFORATED CORRUGATEDPOLYETHYLENE (CPE)DRAINAGE TUBING, DIAMETERMIN. 2" LARGER THAN DEWATERING ORIFICE. TUBING SHALL COMPLY WITH ASTMF667 AND AASHTO M294. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-53 catch basin, while the insert will not. Thus, filter fabric is only allowed where ponding will not be a traffic concern and where slope erosion will not result if the curb is overtopped by ponded water. Trapping sediment in the catch basins is unlikely to improve the water quality of runoff if it is treated in a pond or trap because the coarse particles that are trapped at the catch basin settle out very quickly in the pond or trap. Catch basin protection normally only improves water quality where there is no treatment facility downstream. In these circumstances, catch basin protection is an important last line of defense. It is not, however, a substitute for preventing erosion. The placement of filter fabric under grates is generally prohibited and the use of filter fabric over grates is strictly limited and discouraged. 2. It is sometimes possible to construct a small sump around the catch basin before final surfacing of the road. This is allowed because it can be a very effective method of sediment control. 3. Block and gravel filters, gravel and wire mesh filter barriers, and bag barriers filled with various filtering media placed around catch basins can be effective when the drainage area is 1 acre or less and flows do not exceed 0.5 cfs. It is necessary to allow for overtopping to prevent flooding. Many manufacturers have various inlet protection filters that are very effective in keeping sediment-laden water from entering the storm drainage system. The following are examples of a few common methods. a) Block and gravel filters (Figure D.2.1.5.G) are a barrier formed around an inlet with standard concrete block and gravel, installed as follows: • Height is 1 to 2 feet above the inlet. • Recess the first row of blocks 2 inches into the ground for stability. • Support subsequent rows by placing a 2x4 through the concrete block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pooled water. • Place cloth or mesh with ½ inch openings over all block openings. • Place gravel below the top of blocks on slopes of 2:1 or flatter. • An alternate design is a gravel donut. b) Gravel and wire mesh filters consist of a gravel barrier placed over the top of an inlet. This structure generally does not provide overflow. Install as follows: • Cloth or comparable wire mesh with ½ inch openings is placed over inlet. • Coarse aggregate covers the cloth or mesh. • Height/depth of gravel should be 1 foot or more, 18 inches wider than inlet on all sides. c) Curb inlet protection with a wooden weir is a barrier formed around an inlet with a wooden frame and gravel, installed as follows: • Construct a frame and attach wire mesh (½ inch openings) and filter fabric to the frame. • Pile coarse washed aggregate against the wire/fabric. • Place weight on frame anchors. d) Curb and gutter sediment barriers (Figure D.2.1.5.H) consist of sandbags or rock berms (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape, installed as follows: • Bags of either burlap or woven geotextile fabric, filled with a variety of media such as gravel, wood chips, compost or sand stacked tightly allows water to pond and allows sediment to separate from runoff. • Leave a “one bag gap” in the top row of the barrier to provide a spillway for overflow. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-54 • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 x 3 and at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm to sediment trap standards for protecting a culvert inlet. 4. Excavated drop inlet sediment traps are appropriate where relatively heavy flows are expected and overflow capability is needed. If emergency overflow is provided, additional end-of-pipe treatment may be required. Excavated drop inlets consist of an excavated impoundment area around a storm drain. Sediment settles out of the stormwater prior to enter the drain. Install according to the following specifications: a) The impoundment area should have a depth of 1 to 2 feet measured from the crest of the inlet structure. b) Side slopes of the excavated area must be no steeper than 2:1. c) Minimum volume of the excavated area should be 35 cubic yards. d) Install provisions for draining the area to prevent standing water problems. e) Keep the area clear of debris. f) Weep holes may be drilled into the side of the inlet. g) Protect weep holes with wire mesh and washed aggregate. h) Weep holes must be sealed when removing and stabilizing excavated area. i) A temporary dike may be necessary on the down slope side of the structure to prevent bypass flow. Maintenance Standards 1. Any accumulated sediment on or around inlet protection shall be removed immediately. Sediment shall not be removed with water, and all sediment must be disposed of as fill on site or hauled off site. 2. Any sediment in the catch basin insert shall be removed when the sediment has filled one-third of the available storage. The filter media for the insert shall be cleaned or replaced at least monthly. 3. Regular maintenance is critical for all forms of catch basin/inlet protection. Unlike many forms of protection that fail gradually, catch basin protection will fail suddenly and completely if not maintained properly. FIGURE D.2.1.5.E FILTER FABRIC PROTECTION CATCH BASIN NOTE: ONLY TO BE USED WHERE PONDING OF WATER ABOVE THECATCH BASIN WILL NOT CAUSE TRAFFIC PROBLEMS AND WHEREOVERFLOW WILL NOT RESULT IN EROSION OF SLOPES. GRATESTANDARD STRENGTH FILTER FABRIC D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-55 FIGURE D.2.1.5.F CATCH BASIN INSERT NOTE: THIS DETAIL IS ONLYSCHEMATIC. ANY INSERT IS ALLOWED THAT HAS:•A MIN. 0.5 C.F. OF STORAGE, •THE MEANS TO DEWATER THESTORED SEDIMENT, •AN OVERFLOW, AND•CAN BE EASILY MAINTAINED. OVERFLOW GRATECATCH BASIN POROUS BOTTOM SOLID WALLS FILTER MEDIA FORDEWATERING SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-56 FIGURE D.2.1.5.G BLOCK AND GRAVEL CURB INLET PROTECTION 1.USE BLOCK AND GRAVEL TYPE SEDIMENT BARRIER WHEN CURB INLET IS LOCATEDIN GENTLY SLOPING SEGMENT, WHERE WATER CAN POND AND ALLOW SEDIMENT TOSEPARATE FROM RUNOFF. 2.BARRIER SHALL ALLOW FOR OVERFLOW FROM SEVERE STORM EVENT. 3.INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENTAND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. 2x4 WOOD STUD OVERFLOW WATER A A PLAN VIEWNTS SECTION A-ANTS BLOCK AND GRAVEL CURB INLET PROTECTION NTS CATCH BASIN COVER CURB INLET CONCRETE BLOCKS CATCH BASIN COVER CURB INLET CATCH BASIN BACK OF SIDEWALK CURB FACE 3/4" DRAIN GRAVEL (20 mm) WIRE SCREEN OR FILTER FABRIC POND HEIGHT WIRE SCREENOR FILTER FABRIC 2x4 WOOD STUD(100x50 TIMBER STUD) 3/4" DRAIN GRAVEL (20 mm) NOTES: D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-57 FIGURE D.2.1.5.H CURB AND GUTTER BARRIER PROTECTION RUNOFF RUNOFF SPILLWAY 1.PLACE CURB-TYPE SEDIMENT BARRIERS ON GENTLY SLOPING STREET SEGMENTS,WHERE WATER CAN POND AND ALLOW SEDIMENT TO SEPARATE FROM RUNOFF. 2.SANDBAGS OF EITHER BURLAP OR WOVEN GEOTEXTILE FABRIC ARE FILLED WITHGRAVEL, LAYERED AND PACKED TIGHTLY. 3.LEAVE A ONE-SANDBAG GAP IN THE TOP ROW TO PROVIDE A SPILLWAY FOR OVERFLOW. 4.INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENTAND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. GRAVEL FILLED SANDBAGSSTACKED TIGHTLY DRAIN GRATE GUTTER CURB FACE CURB INLET SANDBAGS TO OVERLAPONTO CURB BACK OF SIDEWALK PLAN VIEW NTS CURB AND GUTTER BARRIER NTS NOTES: SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-58 D.2.1.6 SURFACE WATER COLLECTION All surface water from disturbed areas shall be intercepted, conveyed to a sediment pond or trap, and discharged downslope of any disturbed areas. An exception is for areas at the perimeter of the site with drainage areas small enough to be treated solely with perimeter protection (see Section D.2.1.3). Also, if the soils and topography are such that no offsite discharge of surface water is anticipated up to and including the developed 2-year runoff event, surface water controls are not required. A 10-year approved model 15-minute peak flow shall be used for sizing surface water controls if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection (see the introduction to Section D.2.1.5). At the City’s discretion, sites may be worked during the dry season without surface water controls, if there is some other form of protection of surface waters, such as a 100-foot forested buffer between the disturbed areas and adjacent surface waters. Significant sources of upslope surface water that drain onto disturbed areas shall be intercepted and conveyed to a stabilized discharge point downslope of the disturbed areas. Surface water controls shall be installed concurrently with rough grading. Purpose: The purpose of surface water control is to collect and convey surface water so that erosion is minimized, and runoff from disturbed areas is treated by a sediment pond or trap. Surface water control essentially consists of three elements: 1. Interception of runoff on and above slopes 2. Conveyance of the runoff to a sediment pond or trap (if the runoff was collected from a disturbed area) 3. Release of the runoff downslope of any disturbed areas. When to Install: Surface water controls shall be constructed during the initial grading of an area and must be in place before there is any opportunity for storm runoff to cause erosion. Measures to Install: Interceptor dikes/swales intercept runoff, ditches and pipe slope drains convey the runoff, and riprap or level spreaders help release the runoff in a non-erosive manner. Each measure is to be used under different circumstances so there is very little overlap. However, the two options for releasing water in a non-erosive manner, outlet protection and level spreaders, can be somewhat interchangeable. See Figure D.2.1.6.A for a schematic drawing demonstrating the use of these measures. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-59 FIGURE D.2.1.6.A SKETCH PLAN OF SURFACE WATER CONTROLS D.2.1.6.1 INTERCEPTOR DIKE AND SWALE Code: ID or IS Symbol: or Purpose Interceptor dikes and swales intercept storm runoff from drainage areas on or above disturbed slopes and convey it to a sediment pond or trap. They may also be used to intercept runoff from undisturbed areas and convey the runoff to a point below any exposed soils. Interception of surface water reduces the possibility of slope erosion. Interceptor dikes and swales differ from ditches (see Section D.2.1.6.4) in that they are intended to convey smaller flows along low-gradient drainage ways to larger conveyance systems such as ditches or pipe slope drains. Conditions of Use Interceptor dikes and swales are required in the following situations: 1. At the top of all slopes in excess of 3H:1V and with more than 20 feet of vertical relief. 2. At intervals on any slope that exceeds the dimensions specified in this section for the horizontal spacing of dikes and swales. Design and Installation Specifications 1. See Figure D.2.1.6.B for details of an interceptor dike and Figure D.2.1.6.C for an interceptor swale. 2. Interceptor dikes and swales shall be spaced horizontally as follows: Average Slope Slope Percent Flowpath Length 20H:1V or less 3–5% 300 feet (10 to 20)H:1V 5–10% 200 feet (4 to 10)H:1V 10–25% 100 feet (2 to 4)H:1V 25–50% 50 feet INTERCEPTOR DIKE TOP OF SLOPE TOE OF SLOPE OUTLETPROTECTION DITCH SEDIMENT POND SILT FENCE STREAM PIPE SLOPE DRAIN FLOW ID PD ID OP DI SP SF SF OP SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-60 3. For slopes steeper than 2H:1V with more than 10 feet of vertical relief, benches may be constructed or closer spaced interceptor dikes or swales may be used. Whichever measure is chosen, the spacing and capacity of the measures must be designed by the engineer and the design must include provisions for effectively intercepting the high velocity runoff associated with steep slopes. 4. If the dike or swale intercepts runoff from disturbed areas, it shall discharge to a stable conveyance system that routes the runoff to a sediment pond or trap (see Section D.2.1.5). If the dike or swale intercepts runoff that originates from undisturbed areas, it shall discharge to a stable conveyance system that routes the runoff downslope of any disturbed areas and releases the water at a stabilized outlet. 5. Construction traffic over temporary dikes and swales shall be minimized. Maintenance Standards 1. Damage resulting from runoff or construction activity shall be repaired immediately. 2. If the facilities do not regularly retain storm runoff, the capacity and/or frequency of the dikes/swales shall be increased. FIGURE D.2.1.6.B INTERCEPTOR DIKE FIGURE D.2.1.6.C INTERCEPTOR SWALE DIKE SPACING DEPENDS ON SLOPE GRADIENT 2' MIN.18" MIN. 2 MAX. 12 MAX. 1 DIKE MATERIAL COMPACTED90% MODIFIED PROCTOR SWALE SPACING DEPENDS ON SLOPE GRADIENT 2' MIN. 1' MIN. LEVEL BOTTOM 2:1 MAX. SLOPE D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-61 D.2.1.6.2 PIPE SLOPE DRAINS Code: PD Symbol: Purpose Pipe slope drains are designed to carry concentrated runoff down steep slopes without causing erosion, or saturation of slide-prone soils. Pipe slope drains may be used to divert water away from or over bare soil to prevent gullies, channel erosion, and saturation of slide prone soils Conditions of Use Pipe slope drains should be used when a temporary or permanent stormwater conveyance is needed to move water down a steep slope to avoid erosion. Pipe slope drains may be: 1. Connected to new catch basins and used temporarily until all permanent piping is installed. 2. Used on any slope with a gradient of 2H:1V or greater and with at least 10 feet of vertical relief. 3. Used to drain water collected from aquifers exposed on cut slopes and convey it to the base of the slope. 4. Used to collect clean runoff from plastic sheet cover and direct away from any exposed soils. 5. Installed in conjunction with silt fence to drain collected water to a controlled area. 6. Used to divert small seasonal streams away from construction. Pipe slope drains have been used successfully on culvert replacement and extension projects. Large flex pipe may be used on larger streams during culvert removal, repair, or replacement. 7. Connected to existing downspouts and roof drains used to divert water away from work areas during building renovation, demolition, and construction projects. 8. Rock-lined ditches or other permanent, non-erosive conveyances used to convey runoff down steep slopes that are not steep slope hazard areas. Design and Installation Specifications 1. See Figure D.2.1.6.D for details. 2. The capacity for temporary drains shall be sufficient to handle the developed 10-year peak flow using the approved model with 15-minute time steps. Up to 30,000 square feet may be drained by each 6-inch minimum diameter pipe without computation of the peak flow. Up to 2 acres may be drained by each 12-inch minimum diameter pipe. Otherwise, the peak flow will need to be computed using the Rational Method described in Section 3.2.1 of the SWDM. 3. The maximum drainage area allowed for any sized pipe is 10 acres. For larger areas, more than one pipe shall be used or a rock-lined channel shall be installed (see SWDM Section 4.4.1, “Open Channels”). 4. The soil around and under the pipe and entrance section shall be thoroughly compacted. 5. The flared inlet section shall be securely connected to the slope drain and be fused or welded, or have flange-bolted mechanical joints to ensure a watertight seal. Ensure that the entrance area is stable and large enough to direct flow into the pipe. 6. Slope drains shall be continuously fused, welded, or flange-bolted mechanical joint pipe systems with proper anchoring to the soil. 7. Where slope drains cross steep slope hazard areas or their associated buffers, the installation shall be on the ground surface, accomplished with minimum alteration. In most circumstances, this requires that slope drains be constructed of corrugated metal, CPE, or equivalent pipe and installed by hand SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-62 (see SWDM Section 4.2.1). Any area disturbed during installation or maintenance must be immediately stabilized. 8. If the pipe slope drain will convey sediment-laden runoff, the runoff must be directed to a sediment retention facility (see Section D.2.1.5). If the runoff is not from a disturbed area or is conveyed from a sediment trap or pond, it must be conveyed to a stabilized discharge point (see Section D.2.1.6.5). 9. Re-establish cover immediately on areas disturbed by the installation. Maintenance Standards 1. The inlet shall not be undercut or bypassed by water. If there are problems, the head wall shall be appropriately reinforced. 2. No erosion shall occur at the outlet point. If erosion occurs, additional protection shall be added. FIGURE D.2.1.6.D PIPE SLOPE DRAIN D.2.1.6.3 SUBSURFACE DRAINS Purpose To intercept, collect, and convey ground water to a satisfactory outlet, using a perforated pipe or conduit below the ground surface. Subsurface drains are also known as “French Drains.” The perforated pipe provides a dewatering mechanism to drain excessively wet soils, provide a stable base for construction, improve stability of structures with shallow foundations, or to reduce hydrostatic pressure and to improve slope stability. Conditions of Use Use when excessive water must be removed from the soil. The soil permeability, depth to water table, and impervious layers are all factors that may govern the use of subsurface drains. Design and Installation Specifications 1. Two types of drains may be used as follows: a) Relief drains are used either to lower the water table in large, relatively flat areas, improve the growth of vegetation, or to remove surface water. They are installed along a slope and drain in the direction of the slope. They may be installed in a grid pattern, a herringbone pattern, or a random pattern. b) Interceptor drains are used to remove excess groundwater from a slope, stabilize steep slopes, and lower the water table below a slope to prevent the soil from becoming saturated. They are INLET AND ALL SECTIONSMUST BE SECURELYFASTENED TOGETHER WITH GASKETEDWATERTIGHT FITTINGS DIKE MATERIAL COMPACTED 90% MODIFIED PROCTOR CPE PIPE (LINED ORUNLINED) OR EQUIVALENT INTERCEPTORDIKE INTERCEPTOR DIKE PROVIDE RIPRAP PAD OREQUIVALENT ENERGYDISSIPATION DISCHARGE TO A STABILIZEDWATERCOURSE, SEDIMENTRETENTION FACILITY OR STABILIZED OUTLET STANDARD FLAREDEND SECTION 12"MIN. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-63 installed perpendicular to a slope and drain to the side of the slope. They usually consist of a single pipe or single pipes instead of a patterned layout. 2. Size of Drains – Size subsurface drains to carry the required capacity without pressurized flow. Minimum diameter for a subsurface drain is 4 inches. 3. Outlet – Ensure that the outlet of a drain empties into a channel or other watercourse above the normal water level. Maintenance Standards 1. Subsurface drains shall be checked periodically to ensure that they are free flowing and not clogged with sediment or roots. 2. The outlet shall be kept clear and free of debris. 3. Surface inlets shall be kept open and free of sediment and other debris. 4. Trees located too close to a subsurface drain often clog the system with roots. If a drain becomes clogged, relocate the drain or remove the trees as a last resort. Drain placement should be planned to minimize this problem. 5. Where drains are crossed by heavy equipment, the line shall be checked to ensure that it is not crushed and have adequate cover protection. D.2.1.6.4 DITCHES Code: DI Symbol: Purpose Ditches convey intercepted runoff from disturbed areas to and from sediment ponds or traps. They also convey runoff intercepted from undisturbed areas around the site to a non-erosive discharge point. Conditions of Use Ditches may be used anywhere that concentrated runoff is to be conveyed on or around the construction site. Temporary pipe systems may also be used to convey runoff. Design and Installation Specifications 1. Channels and ditches shall be sized to accommodate the developed condition 10-year approved model 15-minute peak flow with 0.5 feet of freeboard. If no hydrologic analysis is required for the site, the Rational Method may be used (see Section 3.2.1 of the SWDM). 2. See SWDM Section 4.4.1 for open-channel design requirements. 3. The only exception to the requirements of SWDM Section 4.4.1 is the use of check dams, rather than grass lining, for channels in which the design flow velocity does not exceed 5 fps. See Figure D.2.1.6.E for details on check dam installation. Maintenance Standards 1. Any sediment deposition of more than 0.5 feet shall be removed so that the channel is restored to its design capacity. 2. If the channel capacity is insufficient for the design flow, it must be determined whether the problem is local (e.g., a constriction or bend) or the channel is under-designed. If the problem is local, the channel capacity must be increased through construction of a berm(s) or by excavation. If the problem is under-design, the design engineer shall be notified and the channel redesigned to a more conservative standard to be approved by the City of Renton. 3. The channel shall be examined for signs of scouring and erosion of the bed and banks. If scouring or erosion has occurred, affected areas shall be protected by riprap or an erosion control blanket or net. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-64 FIGURE D.2.1.6.E CHECK DAMS D.2.1.6.5 OUTLET PROTECTION Code: OP Symbol: Purpose Outlet protection prevents scour at conveyance outlets. Conditions of Use Outlet protection is required at the outlets of all ponds, pipes, ditches, or other approved conveyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, wetland, lake, or ditch. Design and Installation Specifications For the standard pipe slope drains in Section D.2.1.6.2 and other smaller conveyance systems, the standard rock pad (6 feet by 8 feet) made of 1-foot thick quarry spall is adequate. For all other outlets, the outlet protection shall meet the requirements of the “Outfalls” section of Core Requirement #4 and Section 4.2.2 of the SWDM. Maintenance Standards for Outlet Protection If there is scour at the outlet, the eroded area shall be protected with more conservative measures proposed by the design engineer and approved by the City of Renton. 6" MIN. ROCK MUST COMPLETELY COVER THE BOTTOM AND SIDES OF THE DITCH 24" MIN. 2H:1V SLOPES L 2"- 4" ROCKBA L=THE DISTANCE SUCH THAT POINTS A AND B ARE OF EQUAL ELEVATION CROSS SECTION CHECK DAM SPACING D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-65 D.2.1.6.6 LEVEL SPREADER Code: LS Symbol: Purpose Level spreaders convert concentrated runoff to sheet flow and release it onto areas stabilized by existing vegetation. Conditions of Use Level spreaders may be used where runoff from undisturbed areas or sediment retention facilities is discharged. This practice applies only where the spreader can be constructed on undisturbed soil and the area below the level lip is vegetated and low gradient (see below). Note: Level spreaders are conceptually an ideal way to release stormwater since the vegetation and soil allow for the removal of fines from runoff that cannot be removed by settling or filtration. Unfortunately, the performance record of spreaders in the field is dismal. They are frequently under-designed and, despite the best installations, are rarely perfectly level, which results in the release of stormwater at a particular point. This concentrated runoff can result in catastrophic erosion downslope. Given such design failures, the use of spreaders is not encouraged. However, where slopes are gentle and the water volume is relatively low, spreaders may still be the best method. When proposing their use, the designer shall carefully evaluate the site for possible concerns. Design and Installation Specifications 1. See Figure D.2.1.6.F for detail. Other designs may be used subject to City approval. 2. If runoff velocity as it enters the level spreader is more than 4 fps for the developed condition 10-year approved model 15-minute peak flow, a riprap apron must be provided to dissipate energy before the runoff enters the spreader (Section D.2.1.6.5). 3. The total spreader length shall be at least the square root of the catchment area. The maximum length for an individual spreader is 50 feet, limiting the catchment area that a single spreader may serve to 2500 square feet. Although this is very small, four 50-foot level spreaders next to one another could serve nearly an acre (40,000 square feet). Multiple spreaders shall not be placed uphill or downhill from one another in a configuration that would allow water released from one spreader to enter a downslope spreader. 4. The area below the spreader for a horizontal distance of 100 feet shall not exceed 20 percent and shall be completely vegetated with no areas of instability or erosion. The topography for a horizontal distance of 50 feet below the spreader shall be uniform so that runoff is not funneled into a swale or channel immediately after its release. 5. The level spreader shall be seeded and mulched in accordance with Section D.2.1.2. Maintenance Standards 1. Any damage to the spreader shall be immediately repaired. Ensure flows do not bypass the spreader at the ends of the spreader. 2. The downslope area shall be checked for signs of erosion and to verify that the spreader is not functioning as a point discharge. Any eroded areas shall be immediately stabilized, and the cause determined and eliminated if possible. If the erosion is recurrent and the design, even when properly installed and maintained, is not adequate to prevent erosion, a new method of releasing runoff shall be installed in accordance with the standards of this appendix. Any new design must be approved by the City of Renton. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-66 FIGURE D.2.1.6.F LEVEL SPREADER D.2.1.7 DEWATERING CONTROL Any runoff generated by dewatering shall be treated through construction of a sediment trap (Section D.2.1.5.1) when there is sufficient space or by releasing the water to a well vegetated, gently sloping area. Since pumps are used for dewatering, it may be possible to pump the sediment-laden water well away from the surface water so that vegetation can be more effectively utilized for treatment. Discharge of sediment-laden water from dewatering activities to surface and storm waters is prohibited. If dewatering occurs from areas where the water has come in contact with new concrete, such as tanks, vaults, or foundations, the pH of the water must be monitored and must be neutralized prior to discharge. Clean non-turbid dewatering water, such as well point ground water can be discharged to systems tributary to, or directly to surface waters provided the flows are controlled so no erosion or flooding occurs. Clean water must not be routed through a stormwater sediment pond. Highly turbid or contaminated dewatering water must be handled separately from stormwater. Purpose: To prevent the untreated discharge of sediment-laden water from dewatering of utilities, excavated areas, foundations, etc. When to Install: Dewatering control measures shall be used whenever there is a potential for runoff from dewatering of utilities, excavations, foundations, etc. Measures to install: 1. Foundation, vault, excavation, and trench dewatering water that has similar characteristics to stormwater runoff at the site shall be discharged into a controlled conveyance system prior to discharge to a sediment trap or sediment pond. Foundation and trench dewatering water that has similar characteristics to stormwater runoff at the site must be disposed of through one of the following options depending on site constraints: a) Infiltration, b) Transport offsite in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute surface waters, SPREADER MUST BE LEVEL 18" MIN. REBAR SUPPORTS8' MIN. SPACING CROSS SECTION DETAIL OF SPREADER DENSELY VEGETATED FOR A MIN. OF 100' AND SLOPELESS THAN 5:1 PRESSURE-TREATED2"X10" 3' MIN. TREATED 2"x10" MAY BE ABUTTED END TOEND FOR MAX. SPREADER LENGTH OF 50' 6" MIN. 6" MIN.1" MIN.2H:1V MAX.1' MIN. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-67 c) Discharge to the sanitary sewer discharge with approval from King County and the City of Renton if there is no other option, or d) Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering. 2. Clean, non-turbid dewatering water, such as well-point ground water, may be discharged via stable conveyance to systems tributary to surface waters, provided the dewatering flow does not cause erosion or flooding of receiving waters. 3. Highly turbid or contaminated dewatering water (high pH or other) shall be handled separately from stormwater. See Section D.2.2 , SWPPS Measures. D.2.1.8 DUST CONTROL Preventative measures to minimize the wind transport of soil shall be taken when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources or adjacent properties. Purpose: To prevent wind transport of dust from exposed soil surfaces onto roadways, drainage ways, and surface waters. When to Install: Dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted. Dust control measures may consist of chemical, structural, or mechanical methods. Measures to Install: Water is the most common dust control (or palliative) used in the area. When using water for dust control, the exposed soils shall be sprayed until wet, but runoff shall not be generated by spraying. Calcium chloride, Magnesium chloride, Lignin derivatives, Tree Resin Emulsions, and Synthetic Polymer Emulsions may also be used for dust control. Exposed areas shall be re-sprayed as needed. Oil shall not be used for dust control. The following table lists many common dust control measures. Some of the measures are not recommended for use in the City and must have prior approval prior to use from the CED inspector assigned to specific projects. TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Water -Most commonly used practice -Evaporates quickly -Lasts less than 1 day For all liquid agents: -Blade a small surface -Crown or slope surface to avoid ponding -Compact soils if needed -Uniformly pre-wet at 0.03 – 0.3 gal/sq yd -Apply solution under pressure. Overlap solution 6 – 12 inches -Allow treated area to cure 0 – 4 hours -Compact area after curing -Apply second treatment before first treatment becomes ineffective 0.125 gal/sq yd every 20 to 30 minutes Salts Calcium Chloride (CaCl) -Restricts evaporation -Lasts 6–12 months -Can be corrosive -Less effective in low humidity -Can build up in soils and leach by rain Apply 38% solution at 1.21L/m2 (0.27 gal/yd2) or as loose dry granules per manufacturer SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-68 TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Magnesium Chloride (MgCl) -Restricts evaporation -Works at higher temperatures and lower humidity than CaCl -May be more costly than CaCl Apply 26 – 32% solution at 2.3 L/m2 (0.5 gal/yd2) Sodium Chloride (NaCl) -Effective over smaller range of conditions -Less expensive -Can be corrosive -Less effective in low humidity Per Manufacturer Silicates -Generally expensive -Available in small quantities -Require Second application Surfactants -High evaporation rates -Effective for short time periods -Must apply frequently Copolymers -Forms semi-permeable transparent crust -Resists ultraviolet radiation and moisture induced breakdown -Last 1 to 2 years 750 – 940 L/ha (80 – 100 gal/ac) Petroleum Products -Used oil is prohibited as a dust control method -Bind soil particles -May hinder foliage growth -Environmental and aesthetic concerns -Higher cost Use 57 – 63% resins as base. Apply at 750 – 940 L/ha (80–100 gal/ac) Lignin Sulfonate -Paper industry waste product -Acts as dispersing agent -Best in dry climates -Can be slippery -Will decrease Dissolved Oxygen in waterways therefore cannot be used adjacent to surface water systems Loosen surface 25–50 mm (1–2 inches) Need 4–8% fines Vegetable Oils -Coat grains of soils, so limited binding ability -May become brittle -Limited availability Per Manufacturer Spray on Adhesives -Available as organic or synthetic -Effective on dry, hard soils -Forms a crust -Can last 3 to 4 years Per Manufacturer D.2.1.9 FLOW CONTROL Surface water from disturbed areas must be routed through the project’s onsite flow control facility or other provisions must made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction. Purpose: The purpose of surface water flow control is to mitigate increases in runoff peaks that occur during construction as a result of clearing vegetation, compacting the soil, and adding impervious surface. Such increases can cause or aggravate downstream flooding and erosion. D.2.1 ESC MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-69 When to Install: Surface water flow control shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct the surface water flow control facilities. Measures to Use: The project’s onsite flow control facility or other equivalent storage facility that meets the peak-matching performance criteria stated above. D.2.1.10 PROTECT EXISTING AND PROPOSED STORMWATER FACILITIES AND ON-SITE BMPS Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities and on-site BMPs. Purpose: The purpose of protecting existing and proposed stormwater facility and on-site BMP areas is to avoid sedimentation and soil compaction that would adversely affect infiltration, and also avoid contamination by other pollutants. When to Install: Stormwater facility and on-site BMP area protection shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct stormwater facilities and on-site BMPs. Measures to Use: 1. Protect all stormwater facilities and on-site BMPs and proposed stormwater facility and on-site BMP footprints from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the BMPs/facilities. 2. Stormwater facilities and on-site BMPs shall be restored to their fully functioning condition if they accumulate sediment during construction. Restoring the stormwater facilities and on-site BMPs shall include, at a minimum, removal of sediment and any sediment-laden bioretention soils, and replacing the removed soils with soils meeting the design specification. Replacement with a new fully- functioning stormwater facility and/or on-site BMP may be required if restoration to the fully-functioning condition can’t be accomplished. 3. Prevent compacting Bioretention BMPs/facilities by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. 4. Control erosion and avoid introducing sediment from surrounding land uses onto permeable pavement BMPs. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements. 5. Permeable pavement BMPs fouled with sediments or no longer passing an initial infiltration text must be cleaned using procedures from Appendix A or the manufacturer’s procedures. 6. Keep all heavy equipment off existing soils under stormwater facilities and on-site BMPs that have been excavated to final grade to retain the infiltration rate of the soils. D.2.1.11 MAINTAIN PROTECTIVE BMPS Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. Purpose: The purpose of maintaining protective BMPs is to provide continuous erosion and sediment control protection throughout the life of the project, and avoid sedimentation, soil compaction and contamination by other pollutants that would adversely affect infiltration and surface runoff. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-70 When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Measures to Use: 1. Maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Remove all temporary erosion and sediment control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. 3. Provide protection to all stormwater facilities and on-site BMPs installed for the permanent control of stormwater from sediment and compaction. All stormwater facilities and on-site BMPs that are to remain in place following completion of construction shall be examined and placed in full operating conditions. If sediment enters the stormwater facilities and/or on-site BMPs during construction, it shall be removed and the stormwater facility and on-site BMP shall be returned to the conditions specified in the construction documents or as required for full stormwater facility and on-site BMP replacement. 4. Remove or stabilize trapped sediment on site. Permanently stabilize disturbed soil resulting from removal of erosion and sediment control BMPs or vegetation. D.2.1.12 MANAGE THE PROJECT Coordination and timing of site development activities relative to ESC concerns (Section D.2.4), and timely inspection, maintenance and update of protective measures (Section D.2.3) are necessary to effectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. Projects shall assign a qualified CSWPP Supervisor (Section D.2.3.1) to be the primary contact for ESC and SWPPP issues and reporting, coordination with subcontractors and implementation of the CSWPP plan as a whole. Measures to Use: 1. Phase development projects to the maximum degree practicable and take into account seasonal work limits. 2. Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Conduct site inspections and monitoring in accordance with the Construction Stormwater General Permit and City requirements. 3. Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP in accordance with the Construction Stormwater General Permit and City requirements. 4. Projects that disturb one or more acres must have, site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL) (see Section D.2.3.1). Project sites less than one acre (not part of a larger common plan of development or sale) may have a person without CESCL certification conduct inspections. By the initiation of construction, the SWPPP must identify the CESCL or inspector, who shall be present onsite or on-call at all times. The CESCL or inspector (project sites less than one acre) must have the skills to assess the: • Site conditions and construction activities that could impact the quality of stormwater. • Effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. • The CESCL or inspector must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. They must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-71 Based on the results of the inspection, construction site operators must correct the problems identified by: • Reviewing the SWPPP for compliance with all construction SWPPP elements and making appropriate revisions within 7 days of the inspection. • Immediately beginning the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems not later than within 10 days of the inspection. If installation of necessary treatment BMPs is not feasible within 10 days, the construction site operator may request an extension within the initial 10-day response period. • Documenting BMP implementation and maintenance in the site log book (applies only to sites that have coverage under the Construction Stormwater General Permit). • The CESCL or inspector must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.) The CESCL or inspector may reduce the inspection frequency for temporary stabilized, inactive sites to once every calendar month. D.2.2 SWPPS MEASURES This section details the SWPPS measures that are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsite equipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. These SWPPS measures represent Best Management Practices (BMPs)8 for the control of pollutant drips and spills as well as other impacts related to construction such as increased pH in concrete construction and handling activities. Compliance with each of the SWPPS measures, and with any project-specific control measures, to the extent applicable and necessary to meet the performance criteria in Section D.2.2, and compliance with the CSWPP implementation requirements in Section D.2.4, constitutes overall compliance with the City’s CSWPP Standards. Note: Additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. The standards for each individual SWPPS measure are divided into four sections: 1. Purpose 2. Conditions of Use 3. Design and Installation Specifications 4. Maintenance Requirements. Note that the “Conditions of Use” always refers to site conditions. As site conditions change, SWPPS measures must be changed to remain in compliance with the requirements of this appendix. Whenever compliance with City SWPPS Standards is required, all of the following SWPPS measures must be considered for application to the project site as detailed in the following sections. The construction pollutant generating concerns addressed by the BMPs that follow include: • Concrete handling, washout and disposal(specifically portland cement concrete) • Sawcutting and surfacing activities • Materials delivery, storage and containment 8 Best Management Practices (BMPs) means the best available and reasonable physical, structural, managerial, or behavioral activities, that when singly or in combination, eliminate or reduce the contamination of surface and/or ground waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-72 • Filtration and chemical treatment of construction water to facilitate disposal or discharge to approved locations • Reporting requirements and documentation availability for specific BMP processes Additionally, several of the ESC BMPs described in Section D.2.1 can be applicable to the SWPPS plan, e.g., use of cover, fencing and access protection to protect temporary materials storage locations. The applicant’s material supplier may be a resource (subject to City approval) for BMPs to address specific project applications or proposals. Conditions of approval on adjustments may also specify additional requirements for the SWPPS plan. D.2.2.1 CONCRETE HANDLING Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate concrete, concrete process water, and concrete slurry from entering waters of the state. Conditions of Use Any time concrete is used, utilize these management practices. Concrete construction projects include, but are not limited to, curbs, sidewalks, roads, bridges, foundations, floors, stormwater vaults, retaining walls, driveways and runways. Design and Installation Specifications 1. Ensure that washout of concrete trucks, chutes, pumps, and internals is performed at an approved off-site location or in designated concrete washout areas. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. Refer to BMP D.2.2.2 for information on concrete washout areas. 2. Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. 3. Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. 4. Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. 5. Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. 6. Contain washwater and leftover product in a lined container when no formed areas are available,. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. 7. Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of surface waters. 8. Refer to BMPs D.2.2.7 and D.2.2.8 for pH adjustment requirements. 9. Refer to the Construction Stormwater General Permit for pH monitoring requirements if the project involves one of the following activities: • Significant concrete work (greater than 1,000 cubic yards poured concrete or recycled concrete used over the life of a project). • The use of engineered soils amended with (but not limited to) Portland cement-treated base, cement kiln dust or fly ash. • Discharging stormwater to segments of water bodies on the 303(d) list (Category 5) for high pH. Maintenance Standards Check containers for holes in the liner daily during concrete pours and repair the same day. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-73 D.2.2.2 CONCRETE WASHOUT AREA Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete waste by conducting washout off-site, or performing onsite washout in a designated area to prevent pollutants from entering surface waters or ground water. Conditions of Use Concrete washout area best management practices are implemented on construction projects where: • Concrete is used as a construction material • It is not possible to dispose of all concrete wastewater and washout off-site (ready mix plant, etc.). • Concrete trucks, pumpers, or other concrete coated equipment are washed onsite. Note: If less than 10 concrete trucks or pumpers need to be washed out onsite, the washwater may be disposed of in a formed area awaiting concrete or an upland disposal site where it will not contaminate surface or ground water. The upland disposal site shall be at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. Design and Installation Specifications Implementation The following steps will help reduce stormwater pollution from concrete wastes: 1. Perform washout of concrete trucks at an approved off-site location or in designated concrete washout areas only. 2. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. 3. Do not allow excess concrete to be dumped onsite, except in designated concrete washout areas. 4. Concrete washout areas may be prefabricated concrete washout containers, or self-installed structures (above-grade or below-grade). 5. Prefabricated containers are most resistant to damage and protect against spills and leaks. Companies may offer delivery service and provide regular maintenance and disposal of solid and liquid waste. 6. If self-installed concrete washout areas are used, below-grade structures are preferred over above- grade structures because they are less prone to spills and leaks. 7. Self-installed above-grade structures should only be used if excavation is not practical. Education 1. Discuss the concrete management techniques described in this BMP with the ready-mix concrete supplier before any deliveries are made. 2. Educate employees and subcontractors on the concrete waste management techniques described in this BMP. 3. Arrange for contractor’s superintendent or Certified Erosion and Sediment Control Lead (CESCL) to oversee and enforce concrete waste management procedures. 4. A sign should be installed adjacent to each temporary concrete washout facility to inform concrete equipment operators to utilize the proper facilities. Contracts Incorporate requirements for concrete waste management into concrete supplier and subcontractor agreements. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-74 Location and Placement 1. Locate washout area at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. 2. Allow convenient access for concrete trucks, preferably near the area where the concrete is being poured. 3. If trucks need to leave a paved area to access washout, prevent track-out with a pad of rock or quarry spalls (see BMP D.2.1.4.2). These areas should be far enough away from other construction traffic to reduce the likelihood of accidental damage and spills. 4. The number of facilities you install should depend on the expected demand for storage capacity. 5. On large sites with extensive concrete work, washouts should be placed in multiple locations for ease of use by concrete truck drivers. On-Site Temporary Concrete Washout Facility, Transit Truck Washout Procedures: 1. Temporary concrete washout facilities shall be located a minimum of 50 feet from sensitive areas including storm drain inlets, open drainage facilities, and watercourses. (See Figures D.2.2.2.A, D.2.2.2.B, and D.2.2.2.C). 2. Concrete washout facilities shall be constructed and maintained in sufficient quantity and size to contain all liquid and concrete waste generated by washout operations. 3. Washout of concrete trucks shall be performed in designated areas only. 4. Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area or properly disposed of off-site. 5. Once concrete wastes are washed into the designated area and allowed to harden, the concrete should be broken up, removed, and disposed of per applicable solid waste regulations. Dispose of hardened concrete on a regular basis. 6. Temporary Above-Grade Concrete Washout Facility a) Temporary concrete washout facility (type above grade) should be constructed as shown on the details below, with a recommended minimum length and minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. b) Plastic lining material should be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. 7. Temporary Below-Grade Concrete Washout Facility a) Temporary concrete washout facilities (type below grade) should be constructed as shown on the details below, with a recommended minimum length and minimum width of 10 ft. The quantity and volume should be sufficient to contain all liquid and concrete waste generated by washout operations. b) Lath and flagging should be commercial type. c) Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. d) Liner seams shall be installed in accordance with manufacturers’ recommendations. e) Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the plastic lining material. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-75 Maintenance Standards Inspection and Maintenance 1. Inspect and verify that concrete washout BMPs are in place prior to the commencement of concrete work. 2. During periods of concrete work, inspect daily to verify continued performance. a) Check overall condition and performance. b) Check remaining capacity (% full). c) If using self-installed washout facilities, verify plastic liners are intact and sidewalls are not damaged. d) If using prefabricated containers, check for leaks. 3. Washout facilities shall be maintained to provide adequate holding capacity with a minimum freeboard of 12 inches. 4. Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75% full. 5. If the washout is nearing capacity, vacuum and dispose of the waste material in an approved manner. a) Do not discharge liquid or slurry to waterways, storm drains or directly onto ground. b) Do not use sanitary sewer without local approval. c) Place a secure, non-collapsing, non-water collecting cover over the concrete washout facility prior to predicted wet weather to prevent accumulation and overflow of precipitation. d) Remove and dispose of hardened concrete and return the structure to a functional condition. Concrete may be reused onsite or hauled away for disposal or recycling. 6. When you remove materials from the self-installed concrete washout, build a new structure; or, if the previous structure is still intact, inspect for signs of weakening or damage, and make any necessary repairs. Re-line the structure with new plastic after each cleaning. Removal of Temporary Concrete Washout Facilities 1. When temporary concrete washout facilities are no longer required for the work, the hardened concrete, slurries and liquids shall be removed and properly disposed of. 2. Materials used to construct temporary concrete washout facilities shall be removed from the site of the work and disposed of or recycled. 3. Holes, depressions or other ground disturbance caused by the removal of the temporary concrete washout facilities shall be backfilled, repaired, and stabilized to prevent erosion. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-76 FIGURE D.2.2.2.A CONCRETE WASHOUT AREA (ABOVE GRADE) SECTION B-BNTS SECTION A-ANTS STAPLE DETAILNTS PLANNTS ABOVE GRADE TEMPORARY CONCRETE WASHOUT FACILITYNTS CONCRETE WASHOUT SIGN DETAILNTS 10 mil PLASTICLINING PLANNTS TYPE "ABOVE GRADE" WITHWOOD PLANKS TYPE "ABOVE GRADE" WITH STRAW BALES 10 mil PLASTICLINING 16 GAUGE STEEL WIRE 2" 8" LAG SCREWS ( 12" ) BLACK LETTERS6" HEIGHT PLYWOOD 4' X 2'PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' STRAWBALES(TYP.) STAKE(TYP.) WEDGE LOOSE STRAWBETWEEN BALES SAND OR GRAVEL-FILLEDBAGS IN CORNERS 10' MIN. RECOMMENDED VARIES WOOD OR METAL STAKES(2 PER BALE) STRAW BALES (2BALES HIGH, MAX.) ORIGINAL GROUND 10 mil PLASTICLINING STAPLES (2 PER BALE) SAND OR GRAVEL-FILLED BAGS IN CORNERS NATIVE MATERIAL(OPTIONAL) 10 milPLASTIC LINING WOOD FRAME SECURELY FASTENED AROUNDENTIRE PERIMETER WITHTWO STAKES TWO-STACKED2x12 ROUGH WOOD FRAME STAKE (TYP.) 10' MIN. RECOMMENDED VARIES NOTES: 1.ACTUAL LAYOUT DETERMINED INTHE FIELD2.THE CONCRETE WASHOUT SIGNSHALL BE INSTALLED WITHIN 30' OF THE FACILITY 1' MIN. Adapted from CalTrans Fig4-14 SAC 8-14-02 D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-77 FIGURE D.2.2.2.B CONCRETE WASHOUT AREA (BELOW GRADE) FIGURE D.2.2.2.C PREFABRICATED CONCRETE WASHOUT CONTAINER W/RAMP EARTHEN BERMTYPICAL SECTION NTS BELOW GRADE TEMPORARY CONCRETE WASHOUT FACILITYNTS CONCRETE WASHOUT SIGN DETAIL NTS SANDBAG PLAN NTS Adapted from CalTrans Fig4-14 SAC 8-14-02 10 milPLASTICLINING LAG SCREWS ( 12" ) BLACKLETTERS6" HEIGHT PLYWOOD 4' X 2'PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' EARTHENBERM 10 milPLASTIC LINING SANDBAG 10' MIN. RECOMMENDED VARIES BERM 3' LATH AND FLAGGING ON 3 SIDES NOTES: 1.ACTUAL LAYOUT DETERMINED INTHE FIELD 2.THE CONCRETE WASHOUT SIGNSHALL BE INSTALLED WITHIN 30' OFTHE FACILITY SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-78 D.2.2.3 SAWCUTTING AND SURFACING POLLUTION PREVENTION Purpose Sawcutting and surfacing operations generate slurry and process water that contains fine particles and high pH (concrete cutting), both of which can violate the water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate process water and slurry created through sawcutting or surfacing from entering waters of the State. Conditions of Use Utilize these management practices anytime sawcutting or surfacing operations take place. Sawcutting and surfacing operations include, but are not limited to, sawing, coring, grinding, roughening, hydro-demolition, bridge and road surfacing Design and Installation Specifications 1. Vacuum slurry and cuttings during cutting and surfacing operations. 2. Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. 3. Slurry and cuttings shall not drain to any natural or constructed drainage conveyance including stormwater systems. This may require temporarily blocking catch basins. 4. Dispose of collected slurry and cuttings in a manner that does not violate ground water or surface water quality standards. 5. Do not allow process water generated during hydro-demolition, surface roughening or similar operations to drain to any natural or constructed drainage conveyance including stormwater systems. Dispose process water in a manner that does not violate ground water or surface water quality standards. 6. Handle and dispose cleaning waste material and demolition debris in a manner that does not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. D.2.2.4 MATERIAL DELIVERY, STORAGE, AND CONTAINMENT Purpose Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or watercourses from material delivery and storage. Minimize the storage of hazardous materials onsite, store materials in a designated area, and install secondary containment. Conditions of Use These procedures are suitable for use at all construction sites with delivery and storage of the following materials: • Petroleum products such as fuel, oil and grease • Soil stabilizers and binders (e.g., Polyacrylamide) • Fertilizers, pesticides and herbicides • Detergents • Asphalt and concrete compounds D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-79 • Hazardous chemicals such as acids, lime, adhesives, paints, solvents and curing compounds • Any other material that may be detrimental if released to the environment Design and Installation Specifications The following steps should be taken to minimize risk: 1. Temporary storage area should be located away from vehicular traffic, near the construction entrance(s), and away from waterways or storm drains. 2. Material Safety Data Sheets (MSDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. 3. Hazardous material storage onsite should be minimized. 4. Hazardous materials should be handled as infrequently as possible. 5. During the wet weather season (October 1 – April 30), consider storing materials in a covered area. 6. Materials should be stored in secondary containments, such as earthen dike, horse trough, or even a children’s wading pool for non-reactive materials such as detergents, oil, grease, and paints. Small amounts of material may be secondarily contained in “bus boy” trays or concrete mixing trays. 7. Do not store chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet and, when possible, and within secondary containment. 8. If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of drums, preventing water from collecting. Material Storage Areas and Secondary Containment Practices: 1. Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be stored in approved containers and drums and shall not be overfilled. Containers and drums shall be stored in temporary secondary containment facilities. 2. Temporary secondary containment facilities shall provide for a spill containment volume able to contain 10% of the total enclosed container volume of all containers, or 110% of the capacity of the largest container within its boundary, whichever is greater. 3. Secondary containment facilities shall be impervious to the materials stored therein for a minimum contact time of 72 hours. 4. Secondary containment facilities shall be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed into drums. These liquids shall be handled as hazardous waste unless testing determines them to be non- hazardous. 5. Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. 6. During the wet weather season (October 1 – April 30), each secondary containment facility shall be covered during non-working days, prior to and during rain events. 7. Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). 8. The spill kit should include, at a minimum: • 1-Water Resistant Nylon Bag • 3-Oil Absorbent Socks 3″ x 4′ • 2-Oil Absorbent Socks 3″ x 10′ • 12-Oil Absorbent Pads 17″ x 19″ SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-80 • 1-Pair Splash Resistant Goggles • 3-Pair Nitrile Gloves • 10-Disposable Bags with Ties • Instructions D.2.2.5 CONSTRUCTION STORMWATER CHEMICAL TREATMENT Purpose This BMP applies when using stormwater chemicals in batch treatment or flow-through treatment. Turbidity is difficult to control once fine particles are suspended in stormwater runoff from a construction site. Sedimentation ponds are effective at removing larger particulate matter by gravity settling, but are ineffective at removing smaller particulates such as clay and fine silt. Traditional erosion and sediment control BMPs may not be adequate to ensure compliance with the water quality standards for turbidity in receiving water. Chemical treatment can reliably provide exceptional reductions of turbidity and associated pollutants. Chemical treatment may be required to meet turbidity stormwater discharge requirements, especially when construction is to proceed through the wet season. Conditions of Use Formal written approval from Ecology is required for the use of chemical treatment regardless of site size. The City also requires review and approval. When approved, the chemical treatment systems must be included in the SWPPS portion of the project’s CSWPP. Design and Installation Specifications Coagulation and flocculation have been used for over a century to treat water. It is used less frequently for the treatment of wastewater. The use of coagulation and flocculation for treating stormwater is a very recent application. Experience with the treatment of water and wastewater has resulted in a basic understanding of the process, in particular factors that affect performance. This experience can provide insights as to how to most effectively design and operate similar systems in the treatment of stormwater. Fine particles suspended in water give it a milky appearance, measured as turbidity. Their small size, often much less than 1 μm in diameter, give them a very large surface area relative to their volume. These fine particles typically carry a negative surface charge. Largely because of these two factors, small size and negative charge, these particles tend to stay in suspension for extended periods of time. Thus, removal is not practical by gravity settling. These are called stable suspensions. Polymers, as well as inorganic chemicals such as alum, speed the process of clarification. The added chemical destabilizes the suspension and causes the smaller particles to agglomerate. The process consists of three steps: coagulation, flocculation, and settling or clarification. Each step is explained below as well as the factors that affect the efficiency of the process. Coagulation: Coagulation is the first step. It is the process by which negative charges on the fine particles that prevent their agglomeration are disrupted. Chemical addition is one method of destabilizing the suspension, and polymers are one class of chemicals that are generally effective. Chemicals that are used for this purpose are called coagulants. Coagulation is complete when the suspension is destabilized by the neutralization of the negative charges. Coagulants perform best when they are thoroughly and evenly dispersed under relatively intense mixing. This rapid mixing involves adding the coagulant in a manner that promotes rapid dispersion, followed by a short time period for destabilization of the particle suspension. The particles are still very small and are not readily separated by clarification until flocculation occurs. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-81 Flocculation: Flocculation is the process by which fine particles that have been destabilized bind together to form larger particles that settle rapidly. Flocculation begins naturally following coagulation, but is enhanced by gentle mixing of the destabilized suspension. Gentle mixing helps to bring particles in contact with one another such that they bind and continually grow to form “flocs.” As the size of the flocs increases they become heavier and tend to settle more rapidly. Clarification: The final step is the settling of the particles. Particle density, size and shape are important during settling. Dense, compact flocs settle more readily than less dense, fluffy flocs. Because of this, flocculation to form dense, compact flocs is particularly important during water treatment. Water temperature is important during settling. Both the density and viscosity of water are affected by temperature; these in turn affect settling. Cold temperatures increase viscosity and density, thus slowing down the rate at which the particles settle. The conditions under which clarification is achieved can affect performance. Currents can affect settling. Currents can be produced by wind, by differences between the temperature of the incoming water and the water in the clarifier, and by flow conditions near the inlets and outlets. Quiescent water such as that which occurs during batch clarification provides a good environment for effective performance as many of these factors become less important in comparison to typical sedimentation basins. One source of currents that is likely important in batch systems is movement of the water leaving the clarifier unit. Given that flocs are relatively small and light the exit velocity of the water must be as low as possible. Sediment on the bottom of the basin can be resuspended and removed by fairly modest velocities. Coagulants: Polymers are large organic molecules that are made up of subunits linked together in a chain-like structure. Attached to these chain-like structures are other groups that carry positive or negative charges, or have no charge. Polymers that carry groups with positive charges are called cationic, those with negative charges are called anionic, and those with no charge (neutral) are called nonionic. Cationic polymers can be used as coagulants to destabilize negatively charged turbidity particles present in natural waters, wastewater and stormwater. Aluminum sulfate (alum) can also be used as this chemical becomes positively charged when dispersed in water. In practice, the only way to determine whether a polymer is effective for a specific application is to perform preliminary or onsite testing. Polymers are available as powders, concentrated liquids, and emulsions (which appear as milky liquids). The latter are petroleum based, which are not allowed for construction stormwater treatment. Polymer effectiveness can degrade with time and also from other influences. Thus, manufacturers’ recommendations for storage should be followed. Manufacturer’s recommendations usually do not provide assurance of water quality protection or safety to aquatic organisms. Consideration of water quality protection is necessary in the selection and use of all polymers. Criteria for Chemical Treatment Product Use: Chemically treated stormwater discharged from construction sites must be nontoxic to aquatic organisms. The Chemical Technology Assessment Protocol (CTAPE) must be used to evaluate chemicals proposed for stormwater treatment. Only chemicals approved by Ecology under the CTAPE may be used for stormwater treatment. The approved chemicals, their allowable application techniques (batch treatment or flow-through treatment), allowable application rates, and conditions of use can be found at the Department of Ecology Emerging Technologies website: <http://www.ecy.wa.gov/programs/wq/stormwater/newtech/technologies.html>. Treatment System Design Considerations: The design and operation of a chemical treatment system should take into consideration the factors that determine optimum, cost-effective performance. It is important to recognize the following: • Only Ecology approved chemicals may be used and must follow approved dose rate. • The pH of the stormwater must be in the proper range for the polymers to be effective, which is typically 6.5 to 8.5 SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-82 • The coagulant must be mixed rapidly into the water to ensure proper dispersion. • A flocculation step is important to increase the rate of settling, to produce the lowest turbidity, and to keep the dosage rate as low as possible. • Too little energy input into the water during the flocculation phase results in flocs that are too small and/or insufficiently dense. Too much energy can rapidly destroy floc as it is formed. • Care must be taken in the design of the withdrawal system to minimize outflow velocities and to prevent floc discharge. Discharge from a batch treatment system should be directed through a physical filter such as a vegetated swale that would catch any unintended floc discharge. Currently, flow-through systems always discharge through the chemically enhanced sand filtration system. • System discharge rates must take into account downstream conveyance integrity. Polymer Batch Treatment Process Description: A batch chemical treatment system consists of the stormwater collection system (either temporary diversion or the permanent site drainage system), a storage pond, pumps, a chemical feed system, treatment cells, and interconnecting piping. The batch treatment system shall use a minimum of two lined treatment cells in addition to an untreated stormwater storage pond. Multiple treatment cells allow for clarification of treated water while other cells are being filled or emptied. Treatment cells may be ponds or tanks. Ponds with constructed earthen embankments greater than six feet high or which impound more than 10 acre-feet require special engineering analyses. The Ecology Dam Safety Section has specific design criteria for dams in Washington State (see <http://www.ecy.wa.gov/programs/wr/dams/GuidanceDocs.html>). Stormwater is collected at interception point(s) on the site and is diverted by gravity or by pumping to an untreated stormwater storage pond or other untreated stormwater holding area. The stormwater is stored until treatment occurs. It is important that the holding pond be large enough to provide adequate storage. The first step in the treatment sequence is to check the pH of the stormwater in the untreated stormwater storage pond. The pH is adjusted by the application of carbon dioxide or a base until the stormwater in the storage pond is within the desired pH range, 6.5 to 8.5. When used, carbon dioxide is added immediately downstream of the transfer pump. Typically sodium bicarbonate (baking soda) is used as a base, although other bases may be used. When needed, base is added directly to the untreated stormwater storage pond. The stormwater is recirculated with the treatment pump to provide mixing in the storage pond. Initial pH adjustments should be based on daily bench tests. Further pH adjustments can be made at any point in the process. Once the stormwater is within the desired pH range (dependent on polymer being used), the stormwater is pumped from the untreated stormwater storage pond to a treatment cell as polymer is added. The polymer is added upstream of the pump to facilitate rapid mixing. After polymer addition, the water is kept in a lined treatment cell for clarification of the sediment-floc. In a batch mode process, clarification typically takes from 30 minutes to several hours. Prior to discharge samples are withdrawn for analysis of pH, flocculent chemical concentration, and turbidity. If both are acceptable, the treated water is discharged. Several configurations have been developed to withdraw treated water from the treatment cell. The original configuration is a device that withdraws the treated water from just beneath the water surface using a float with adjustable struts that prevent the float from settling on the cell bottom. This reduces the possibility of picking up sediment-floc from the bottom of the pond. The struts are usually set at a minimum clearance of about 12 inches; that is, the float will come within 12 inches of the bottom of the cell. Other systems have used vertical guides or cables which constrain the float, allowing it to drift up and down with the water level. More recent designs have an H-shaped array of pipes, set on the horizontal. This scheme provides for withdrawal from four points rather than one. This configuration reduces the likelihood of sucking settled solids from the bottom. It also reduces the tendency for a vortex to form. Inlet diffusers, a long floating or fixed pipe with many small holes in it, are also an option. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-83 Safety is a primary concern. Design should consider the hazards associated with operations, such as sampling. Facilities should be designed to reduce slip hazards and drowning. Tanks and ponds should have life rings, ladders, or steps extending from the bottom to the top. Polymer Flow-Through Treatment Process Description: At a minimum, a flow-through chemical treatment system consists of the stormwater collection system (either temporary diversion or the permanent site drainage system), an untreated stormwater storage pond, and the chemically enhanced sand filtration system. Stormwater is collected at interception point(s) on the site and is diverted by gravity or by pumping to an untreated stormwater storage pond or other untreated stormwater holding area. The stormwater is stored until treatment occurs. It is important that the holding pond be large enough to provide adequate storage. Stormwater is then pumped from the untreated stormwater storage pond to the chemically enhanced sand filtration system where polymer is added. Adjustments to pH may be necessary before chemical addition. The sand filtration system continually monitors the stormwater for turbidity and pH. If the discharge water is ever out of an acceptable range for turbidity or pH, the water is recycled to the untreated stormwater pond where it can be retreated. For batch treatment and flow-through treatment, the following equipment should be located in a lockable shed: • The chemical injector. • Secondary containment for acid, caustic, buffering compound, and treatment chemical. • Emergency shower and eyewash. • Monitoring equipment which consists of a pH meter and a turbidimeter. System Sizing: Certain sites are required to implement flow control for the developed sites. These sites must also control stormwater release rates during construction. Generally, these are sites that discharge stormwater directly, or indirectly, through a conveyance system, into a fresh water. System sizing is dependent on flow control requirements. Sizing Criteria for Batch Treatment Systems for Flow Control Exempt Water Bodies: The total volume of the untreated stormwater storage pond and treatment ponds or tanks must be large enough to treat stormwater that is produced during multiple day storm events. It is recommended that at a minimum the untreated stormwater storage pond be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event. Bypass should be provided around the chemical treatment system to accommodate extreme storm events. Runoff volume shall be calculated using the methods presented in Chapter 3 of the SWDM. Worst-case land cover conditions (i.e., producing the most runoff) should be used for analyses (in most cases, this would be the land cover conditions just prior to final landscaping). Primary settling should be encouraged in the untreated stormwater storage pond. A forebay with access for maintenance may be beneficial. There are two opposing considerations in sizing the treatment cells. A larger cell is able to treat a larger volume of water each time a batch is processed. However, the larger the cell the longer the time required to empty the cell. A larger cell may also be less effective at flocculation and therefore require a longer settling time. The simplest approach to sizing the treatment cell is to multiply the allowable discharge flow rate times the desired drawdown time. A 4-hour drawdown time allows one batch per cell per 8-hour work period, given 1 hour of flocculation followed by two hours of settling. If the discharge is directly to a direct discharge exempt receiving water in Section 1.2.3 (Core Requirement #3) of the SWDM, or to an infiltration system, there is no discharge flow limit. Ponds sized for flow control water bodies must at a minimum meet the sizing criteria for direct discharge exempt receiving waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-84 Sizing Criteria for Flow-Through Treatment Systems for Flow Control Exempt Water Bodies: When sizing storage ponds or tanks for flow-through systems for flow control exempt water bodies, the treatment system capacity should be a factor. The untreated stormwater storage pond or tank should be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event minus the treatment system flowrate for an 8-hour period. For a chitosan-enhanced sand filtration system, the treatment system flowrate should be sized using a hydraulic loading rate between 6 to 8 gpm/ft². Other hydraulic loading rates may be more appropriate for other systems. Bypass should be provided around the chemical treatment system to accommodate extreme storms. Runoff volume shall be calculated using the methods presented in Chapter 3 of the SWDM. Worst-case land cover conditions (i.e., producing the most runoff) should be used for analyses (in most cases, this would be the land cover conditions just prior to final landscaping). Sizing Criteria for Flow Control Water Bodies: Sites that must implement flow control for the developed site condition must also control stormwater release rates during construction. Construction site stormwater discharges shall not exceed the discharge durations of the pre-developed condition for the range of pre-developed discharge rates from ½ of the 2-year flow through the 10-year flow as predicted by an approved continuous runoff model. The pre- developed condition to be matched shall be the land cover condition immediately prior to the development project. This restriction on release rates can affect the size of the storage pond and treatment cells. The following is how WWHM can be used to determine the release rates from the chemical treatment systems: 1. Determine the pre-developed flow durations to be matched by entering the existing land use area under the “Pre-developed” scenario in WWHM. The default flow range is from ½ of the 2-year flow through the 10-year flow. 2. Enter the post developed land use area in the “Developed Unmitigated” scenario in WWHM. 3. Copy the land use information from the “Developed Unmitigated” to “Developed Mitigated” scenario. 4. While in the “Developed Mitigated” scenario, add a pond element under the basin element containing the post-developed land use areas. This pond element represents information on the available untreated stormwater storage and discharge from the chemical treatment system. In cases where the discharge from the chemical treatment system is controlled by a pump, a stage/storage/discharge (SSD) table representing the pond must be generated outside WWHM and imported into WWHM. WWHM can route the runoff from the post-developed condition through this SSD table (the pond) and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial SSD table proved to be inadequate, the designer would have to modify the SSD table outside WWHM and re-import in WWHM and route the runoff through it again. The iteration will continue until a pond that complies with the flow duration standard is correctly sized. Notes on SSD table characteristics: • The pump discharge rate would likely be initially set at just below ½ of the 2-year flow from the pre-developed condition. As runoff coming into the untreated stormwater storage pond increases and the available untreated stormwater storage volume gets used up, it would be necessary to increase the pump discharge rate above ½ of the 2-year. The increase(s) above ½ of the 2-year must be such that they provide some relief to the untreated stormwater storage needs but at the same time will not cause violations of the flow duration standard at the higher flows. The final design SSD table will identify the appropriate pumping rates and the corresponding stage and storages. • When building such a flow control system, the design must ensure that any automatic adjustments to the pumping rates will be as a result of changes to the available storage in accordance with the final design SSD table. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-85 5. It should be noted that the above procedures would be used to meet the flow control requirements. The chemical treatment system must be able to meet the runoff treatment requirements. It is likely that the discharge flow rate of ½ of the 2-year or more may exceed the treatment capacity of the system. If that is the case, the untreated stormwater discharge rate(s) (i.e., influent to the treatment system) must be reduced to allow proper treatment. Any reduction in the flows would likely result in the need for a larger untreated stormwater storage volume. If the discharge is to a municipal storm drainage system, the allowable discharge rate may be limited by the capacity of the public system. It may be necessary to clean the municipal storm drainage system prior to the start of the discharge to prevent scouring solids from the drainage system. If the municipal storm drainage system discharges to a water body not on the flow control exempt list, the project site is subject to flow control requirements. Obtain permission from the owner of the collection system before discharging to it. If system design does not allow you to discharge at the slower rates as described above and if the site has a retention or detention pond that will serve the planned development, the discharge from the treatment system may be directed to the permanent retention/detention pond to comply with the flow control requirement. In this case, the untreated stormwater storage pond and treatment system will be sized according to the sizing criteria for flow-through treatment systems for flow control exempt water bodies described earlier except all discharge (water passing through the treatment system and stormwater bypassing the treatment system) will be directed into the permanent retention/detention pond. If site constraints make locating the untreated stormwater storage pond difficult, the permanent retention/detention pond may be divided to serve as the untreated stormwater storage pond and the post-treatment flow control pond. A berm or barrier must be used in this case so the untreated water does not mix with the treated water. Both untreated stormwater storage requirements, and adequate post-treatment flow control must be achieved. The post-treatment flow control pond’s revised dimensions must be entered into the WWHM and the WWHM must be run to confirm compliance with the flow control requirement. Maintenance Standards Monitoring: At a minimum, the following monitoring shall be conducted. Test results shall be recorded on a daily log kept on site. Additional testing may be required by the NPDES permit based on site conditions. Operational Monitoring: • Total volume treated and discharged. • Flow must be continuously monitored and recorded at not greater than 15-minute intervals. • Type and amount of chemical used for pH adjustment. • Amount of polymer used for treatment. • Settling time. Compliance Monitoring: Influent and effluent pH, flocculent chemical concentration, and turbidity must be continuously monitored and recorded at not greater than 15-minute intervals. pH and turbidity of the receiving water. Biomonitoring: Treated stormwater must be non-toxic to aquatic organisms. Treated stormwater must be tested for aquatic toxicity or residual chemicals. Frequency of biomonitoring will be determined by Ecology. Residual chemical tests must be approved by Ecology prior to their use. If testing treated stormwater for aquatic toxicity, you must test for acute (lethal) toxicity. Bioassays shall be conducted by a laboratory accredited by Ecology, unless otherwise approved by Ecology. Acute toxicity tests shall be conducted per the CTAPE protocol. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-86 Discharge Compliance: Prior to discharge, treated stormwater must be sampled and tested for compliance with pH, flocculent chemical concentration, and turbidity limits. These limits may be established by the Construction Stormwater General Permit or a site-specific discharge permit. Sampling and testing for other pollutants may also be necessary at some sites. pH must be within the range of 6.5 to 8.5 standard units and not cause a change in the pH of the receiving water of more than 0.2 standard units. Treated stormwater samples and measurements shall be taken from the discharge pipe or another location representative of the nature of the treated stormwater discharge. Samples used for determining compliance with the water quality standards in the receiving water shall not be taken from the treatment pond prior to decanting. Compliance with the water quality standards is determined in the receiving water. Operator Training: Each contractor who intends to use chemical treatment shall be trained by an experienced contractor. Each site using chemical treatment must have an operator trained and certified by an organization approved by Ecology. Standard BMPs: Surface stabilization BMPs should be implemented on site to prevent significant erosion. All sites shall use a truck wheel wash to prevent tracking of sediment off site. Sediment Removal and Disposal: • Sediment shall be removed from the storage or treatment cells as necessary. Typically, sediment removal is required at least once during a wet season and at the decommissioning of the cells. Sediment remaining in the cells between batches may enhance the settling process and reduce the required chemical dosage. • Sediment that is known to be non-toxic may be incorporated into the site away from drainages. D.2.2.6 CONSTRUCTION STORMWATER FILTRATION Purpose Filtration removes sediment from runoff originating from disturbed areas of the site. Background Information: Filtration with sand media has been used for over a century to treat water and wastewater. The use of sand filtration for treatment of stormwater has developed recently, generally to treat runoff from streets, parking lots, and residential areas. The application of filtration to construction stormwater treatment is currently under development. Conditions of Use Traditional BMPs used to control soil erosion and sediment loss from sites under development may not be adequate to ensure compliance with the water quality standard for turbidity in the receiving water. Filtration may be used in conjunction with gravity settling to remove sediment as small as fine silt (0.5 μm). The reduction in turbidity will be dependent on the particle size distribution of the sediment in the stormwater. In some circumstances, sedimentation and filtration may achieve compliance with the water quality standard for turbidity. The use of construction stormwater filtration does not require approval from Ecology as long as treatment chemicals are not used. Filtration in conjunction with polymer treatment requires testing under the Chemical Technology Assessment Protocol – Ecology (CTAPE) before it can be initiated. Approval from the appropriate regional Ecology office must be obtained at each site where polymers use is proposed prior to use. For more guidance on stormwater chemical treatment see BMP D.2.2.5. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-87 Design and Installation Specifications Two types of filtration systems may be applied to construction stormwater treatment: rapid and slow. Rapid sand filters are the typical system used for water and wastewater treatment. They can achieve relatively high hydraulic flow rates, on the order of 2 to 20 gpm/sf, because they have automatic backwash systems to remove accumulated solids. In contrast, slow sand filters have very low hydraulic rates, on the order of 0.02 gpm/sf, because they do not have backwash systems. Slow sand filtration has generally been used to treat stormwater. Slow sand filtration is mechanically simple in comparison to rapid sand filtration but requires a much larger filter area. Filtration Equipment Sand media filters are available with automatic backwashing features that can filter to 50 μm particle size. Screen or bag filters can filter down to 5 μm. Fiber wound filters can remove particles down to 0.5 μm. Filters should be sequenced from the largest to the smallest pore opening. Sediment removal efficiency will be related to particle size distribution in the stormwater. Treatment Process Description Stormwater is collected at interception point(s) on the site and is diverted to an untreated stormwater sediment pond or tank for removal of large sediment and storage of the stormwater before it is treated by the filtration system. The untreated stormwater is pumped from the trap, pond, or tank through the filtration system in a rapid sand filtration system. Slow sand filtration systems are designed as flow through systems using gravity. Maintenance Standards Rapid sand filters typically have automatic backwash systems that are triggered by a pre-set pressure drop across the filter. If the backwash water volume is not large or substantially more turbid than the untreated stormwater stored in the holding pond or tank, backwash return to the untreated stormwater pond or tank may be appropriate. However, other means of treatment and disposal may be necessary. • Screen, bag, and fiber filters must be cleaned and/or replaced when they become clogged. • Sediment shall be removed from the storage and/or treatment ponds as necessary. Typically, sediment removal is required once or twice during a wet season and at the decommissioning of the ponds. Sizing Criteria for Flow-Through Treatment Systems for Flow Control Exempt Water Bodies: When sizing storage ponds or tanks for flow-through systems for flow control exempt water bodies the treatment system capacity should be a factor. The untreated stormwater storage pond or tank should be sized to hold 1.5 times the runoff volume of the 10-year, 24-hour storm event minus the treatment system flowrate for an 8-hour period. For a chitosan-enhanced sand filtration system, the treatment system flowrate should be sized using a hydraulic loading rate between 6 to 8 gpm/ft². Other hydraulic loading rates may be more appropriate for other systems. Bypass should be provided around the chemical treatment system to accommodate extreme storms. Runoff volume shall be calculated using the methods presented in Chapter 3 of the SWDM (if no chemicals are proposed for use). Worst-case conditions (i.e., producing the most runoff) should be used for analyses (most likely conditions present prior to final landscaping). Sizing Criteria for Flow Control Water Bodies: Sites that must implement flow control for the developed site condition must also control stormwater release rates during construction. Construction site stormwater discharges shall not exceed the discharge durations of the pre-developed condition for the range of pre-developed discharge rates from 1/2 of the 2-year flow through the 10-year flow as predicted by an approved continuous runoff model. The pre-developed condition to be matched shall be the land cover condition immediately prior to the development project. This restriction on release rates can affect the size of the storage pond, the filtration system, and the flow rate through the filter system. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-88 The following is how WWHM can be used to determine the release rates from the filtration systems: 1. Determine the pre-developed flow durations to be matched by entering the land use area under the “Pre-developed” scenario in WWHM. The default flow range is from ½ of the 2-year flow through the 10-year flow. 2. Enter the post developed land use area in the “Developed Unmitigated” scenario in WWHM. 3. Copy the land use information from the “Developed Unmitigated” to “Developed Mitigated” scenario. 4. There are two possible ways to model stormwater filtration systems: a) The stormwater filtration system uses an untreated stormwater storage pond/tank and the discharge from this pond/tank is pumped to one or more filters. In-line filtration chemicals would be added to the flow right after the pond/tank and before the filter(s). Because the discharge is pumped, WWHM can’t generate a stage/storage /discharge (SSD) table for this system. This system is modeled the same way as described Ecology’s BMP C250 (or BMP D.2.2.5 when seeking City approval for non-chemical treatment) and is as follows: While in the “Developed Mitigated” scenario, add a pond element under the basin element containing the post-developed land use areas. This pond element represents information on the available untreated stormwater storage and discharge from the filtration system. In cases where the discharge from the filtration system is controlled by a pump, a stage/storage/discharge (SSD) table representing the pond must be generated outside WWHM and imported into WWHM. WWHM can route the runoff from the post-developed condition through this SSD table (the pond) and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial SSD table proved to be out of compliance, the designer would have to modify the SSD table outside WWHM and re-import in WWHM and route the runoff through it again. The iteration will continue until a pond that enables compliance with the flow duration standard is designed. Notes on SSD table characteristics: • The pump discharge rate would likely be initially set at just below ½ if the 2-year flow from the pre-developed condition. As runoff coming into the untreated stormwater storage pond increases and the available untreated stormwater storage volume gets used up, it would be necessary to increase the pump discharge rate above ½ of the 2-year. The increase(s) above ½ of the 2-year must be such that they provide some relief to the untreated stormwater storage needs but at the same time they will not cause violations of the flow duration standard at the higher flows. The final design SSD table will identify the appropriate pumping rates and the corresponding stage and storages. • When building such a flow control system, the design must ensure that any automatic adjustments to the pumping rates will be as a result of changes to the available storage in accordance with the final design SSD table. b) The stormwater filtration system uses a storage pond/tank and the discharge from this pond/tank gravity flows to the filter. This is usually a slow sand filter system and it is possible to model it in WWHM as a Filter element or as a combination of Pond and Filter element placed in series. The stage/storage/discharge table(s) may then be generated within WWHM as follows: i. While in the “Developed Mitigated” scenario, add a Filter element under the basin element containing the post-developed land use areas. The length and width of this filter element would have to be the same as the bottom length and width of the upstream untreated stormwater storage pond/tank. ii. In cases where the length and width of the filter is not the same as those for the bottom of the upstream untreated stormwater storage tank/pond, the treatment system may be modeled as a Pond element followed by a Filter element. By having these two elements, WWHM would then generate a SSD table for the storage pond which then gravity flows to the Filter element. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-89 The Filter element downstream of the untreated stormwater storage pond would have a storage component through the media, and an overflow component for when the filtration capacity is exceeded. WWHM can route the runoff from the post-developed condition through the treatment systems in 4b and determine compliance with the flow duration standard. This would be an iterative design procedure where if the initial sizing estimates for the treatment system proved to be inadequate, the designer would have to modify the system and route the runoff through it again. The iteration would continue until compliance with the flow duration standard is achieved. 5. It should be noted that the above procedures would be used to meet the flow control requirements. The filtration system must be able to meet the runoff treatment requirements. It is likely that the discharge flow rate of ½ of the 2-year or more may exceed the treatment capacity of the system. If that is the case, the untreated stormwater discharge rate(s) (i.e., influent to the treatment system) must be reduced to allow proper treatment. Any reduction in the flows would likely result in the need for a larger untreated stormwater storage volume. If system design does not allow you to discharge at the slower rates as described above and if the site has a retention or detention pond that will serve the planned development, the discharge from the treatment system may be directed to the permanent retention/detention pond to comply with the flow control requirements. In this case, the untreated stormwater storage pond and treatment system will be sized according to the sizing criteria for flow-through treatment systems for flow control exempt waterbodies described earlier except all discharges (water passing through the treatment system and stormwater bypassing the treatment system) will be directed into the permanent retention/detention pond. If site constraints make locating the untreated stormwater storage pond difficult, the permanent retention/detention pond may be divided to serve as the untreated stormwater discharge pond and the post-treatment flow control pond. A berm or barrier must be used in this case so the untreated water does not mix with the treated water. Both untreated stormwater storage requirements, and adequate post-treatment flow control must be achieved. The post-treatment flow control pond’s revised dimensions must be entered into the WWHM and the WWHM must be run to confirm compliance with the flow control requirement. D.2.2.7 HIGH PH NEUTRALIZATION USING CO2 Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the pH levels to the acceptable range of 6.5 to 8.5, this process is called pH neutralization. pH neutralization involves the use of solid or compressed carbon dioxide gas in water requiring neutralization. Neutralized stormwater may be discharged to surface waters under the Construction Stormwater General permit. Neutralized process water such as concrete truck wash-out, hydro-demolition, or saw-cutting slurry must be managed to prevent discharge to surface waters. Any stormwater contaminated during concrete work is considered process wastewater and must not be discharged to surface waters. Reason for pH Neutralization: A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and this neutral pH is required for the survival of aquatic organisms. Should the pH rise or drop out of this range, fish and other aquatic organisms may become stressed and may die. Calcium hardness can contribute to high pH values and cause toxicity that is associated with high pH conditions. A high level of calcium hardness in waters of the state is not allowed. The water quality standard for pH in Washington State is in the range of 6.5 to 8.5. Ground water standard for calcium and other dissolved solids in Washington State is less than 500 mg/l. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-90 Conditions of Use Causes of High pH: High pH at construction sites is most commonly caused by the contact of stormwater with poured or recycled concrete, cement, mortars, and other Portland cement or lime containing construction materials. (See BMP D.2.2.1, Concrete Handling for more information on concrete handling procedures). The principal caustic agent in cement is calcium hydroxide (free lime). Advantages of CO2 Sparging: • Rapidly neutralizes high pH water. • Cost effective and safer to handle than acid compounds. • CO2 is self-buffering. It is difficult to overdose and create harmfully low pH levels. • Material is readily available. The Chemical Process: When carbon dioxide (CO2) is added to water (H2O), carbonic acid (H2CO3) is formed which can further dissociate into a proton (H+) and a bicarbonate anion (HCO3-) as shown below: CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3- The free proton is a weak acid that can lower the pH. Water temperature has an effect on the reaction as well. The colder the water temperature is the slower the reaction occurs and the warmer the water temperature is the quicker the reaction occurs. Most construction applications in Washington State have water temperatures in the 50°F or higher range so the reaction is almost simultaneous. Design and Installation Specifications Treatment Process: High pH water may be treated using continuous treatment, continuous discharge systems. These manufactured systems continuously monitor influent and effluent pH to ensure that pH values are within an acceptable range before being discharged. All systems must have fail safe automatic shut off switches in the event that pH is not within the acceptable discharge range. Only trained operators may operate manufactured systems. System manufacturers often provide trained operators or training on their devices. The following procedure may be used when not using a continuous discharge system: 1. Prior to treatment, the appropriate jurisdiction should be notified in accordance with the regulations set by the jurisdiction. 2. Every effort should be made to isolate the potential high pH water in order to treat it separately from other stormwater onsite. 3. Water should be stored in an acceptable storage facility, detention pond, or containment cell prior to treatment. 4. Transfer water to be treated to the treatment structure. Ensure that treatment structure size is sufficient to hold the amount of water that is to be treated. Do not fill tank completely, allow at least 2 feet of freeboard. 5. The operator samples the water for pH and notes the clarity of the water. As a rule of thumb, less CO2 is necessary for clearer water. This information should be recorded. 6. In the pH adjustment structure, add CO2 until the pH falls in the range of 6.9 to 7.1. Remember that pH water quality standards apply so adjusting pH to within 0.2 pH units of receiving water (background pH) is recommended. It is unlikely that pH can be adjusted to within 0.2 pH units using dry ice. Compressed carbon dioxide gas should be introduced to the water using a carbon dioxide diffuser located near the bottom of the tank, this will allow carbon dioxide to bubble up through the water and diffuse more evenly. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-91 7. Slowly discharge the water making sure water does not get stirred up in the process. Release about 80% of the water from the structure leaving any sludge behind. 8. Discharge treated water through a pond or drainage system. 9. Excess sludge needs to be disposed of properly as concrete waste. If several batches of water are undergoing pH treatment, sludge can be left in treatment structure for the next batch treatment. Dispose of sludge when it fills 50% of tank volume. Sites that must implement flow control for the developed site must also control stormwater release rates during construction. All treated stormwater must go through a flow control facility before being released to surface waters which require flow control. Maintenance Standards Safety and Materials Handling: • All equipment should be handled in accordance with OSHA rules and regulations. • Follow manufacturer guidelines for materials handling. Operator Records: Each operator should provide: • A diagram of the monitoring and treatment equipment. • A description of the pumping rates and capacity the treatment equipment is capable of treating. Each operator should keep a written record of the following: • Client name and phone number. • Date of treatment. • Weather conditions. • Project name and location. • Volume of water treated. • pH of untreated water. • Amount of CO2 needed to adjust water to a pH range of 6.9 to 7.1. • pH of treated water. • Discharge point location and description. A copy of this record should be given to the client/contractor who should retain the record for 3 years. D.2.2.8 PH CONTROL FOR HIGH PH WATER Purpose When pH levels in stormwater rise above 8.5 it is necessary to lower the pH levels to the acceptable range of 6.5 to 8.5, this process is called pH neutralization. Stormwater with pH levels exceeding water quality standards may be treated by infiltration, dispersion in vegetation or compost, pumping to a sanitary sewer, disposal at a permitted concrete batch plant with pH neutralization capabilities, or carbon dioxide sparging. BMP D.2.2.7, High pH Neutralization Using CO2 gives guidelines for carbon dioxide sparging. Reason for pH Neutralization: A pH level range of 6.5 to 8.5 is typical for most natural watercourses, and this pH range is required for the survival of aquatic organisms. Should the pH rise or drop out of this range, fish and other aquatic organisms may become stressed and may die. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-92 Conditions of Use Causes of High pH: High pH levels at construction sites are most commonly caused by the contact of stormwater with poured or recycled concrete, cement, mortars, and other Portland cement or lime containing construction materials. (See BMP D.2.2.1, Concrete Handling for more information on concrete handling procedures). The principal caustic agent in cement is calcium hydroxide (free lime). Design and Installation Specifications Disposal Methods: Infiltration • Infiltration is only allowed if soil type allows all water to infiltrate (no surface runoff) without causing or contributing to a violation of surface or ground water quality standards. • Infiltration techniques should be consistent with Chapter 5 of the SWDM Dispersion • Dispersion techniques should be consistent with Appendix C of the SWDM Sanitary Sewer Disposal • Approval from King County and the City of Renton is required prior to disposal via the sanitary sewer. Concrete Batch Plant Disposal • Only permitted facilities may accept high pH water. • Facility should be contacted before treatment to ensure they can accept the high pH water. Stormwater Discharge Any pH treatment options that generate treated water that must be discharged off site are subject to flow control requirements. Sites that must implement flow control for the developed site must also control stormwater release rates during construction. All treated stormwater must go through a flow control facility before being released to surface waters which require flow control. D.2.2.9 USE OF HIGH PH SOIL AMENDMENTS ON CONSTRUCTION SITES The use of soil amendments (including cement treated base [CTB] and cement kiln dust [CKD]) on development sites must be approved by the City. The approval process is described in “Processing Requirements for Use of Soil Amendments on Construction Sites” below. Use of Soil Amendments It is sometimes a construction practice to add soil amendments to the surfaces of some construction areas in order to stabilize the ground for building. This practice includes placing an additive on the ground then mixing with the soil to a specified depth and finally compacting the mix. When mixed with the soil, the moisture in the ground may allow these additives to create a chemical reaction that cures similar to concrete and may absorb excessive moisture to allow soils to be compacted. The end result is a stable site for constructing a road or building pad. Because soil amendments may be rich in lime content and other material, water runoff from these areas can be affected. If not controlled and treated, this could result in a degradation of water quality and natural drainage systems. Because these additives come in a fine powder form, the actual application can create fugitive dust. When mixed with water, some additives can become corrosive. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-93 Definitions The following are definitions of soil amendment products that are allowed for use under these procedures: 1. Cement Kiln Dust (CKD) is a by-product in the manufacturing of cement9. 2. Cement Treated Base (CTB) utilizes Portland Cement Type II as the soil additive. CTB/CKD Soil Amendment BMPs Table D.2.2.9.A on the following pages lists twelve BMP categories of action and specific BMPs for each category to be applied when proposing CTB/CKD soil amendments or using soil amendments onsite. Note: Additional BMPs may be required to prevent adverse impacts to the public and/or the environment. It is the responsibility of the permit holder to remain in compliance with all other applicable local, state, and federal regulations. TABLE D.2.2.9.A CTB/CKD SOIL AMENDMENT BMPS Category of Action Specific Action CTB/CKD Best Management Practices 1. Materials Source Analysis Solubility Testing & Specifications A. If CKD is proposed, a chemical analysis of soluble pollutants of the product to be used will be provided to the Washington State Department of Ecology (Ecology) and the CED review staff in advance of any product is applied. B. CTB/CKD mixing percentage is anticipated to be approximately 3 percent to 5 percent. C. A Geotechnical Engineer will establish the mixing percentage for the onsite soils. D. All treatment procedures shall be directed, monitored, and verified by a Geotechnical Engineer. E. Soil amendments will never occur in excess of the ability of the onsite equipment and resources to meet all BMP requirements specified herein. 2. Site Preparation Runoff Collection System A. Areas that are to be treated as shown on the plan are flagged off to prevent equipment from leaving treated area and going onto untreated areas, and to prevent unauthorized equipment from entering the treated area. B. Assessment of surface runoff collection points are noted. C. Cutoff trenches, collection sumps, and pumps are installed. D. Sealed storage tanks will be properly sized to contain all runoff from treated areas. E. Sealed storage tanks shall be set up and ready for use to treat contact water. F. An approved wheel wash will be constructed at the construction exit, typically a paved ramp sump that utilizes high-pressure washers. G. Copies of Treatment Plan, Approval, and Contingency Plan area are required to be located on site. 9 CKD is collected by air pollution control devices used to clean kiln exhaust during the manufacturing of Portland Cement. EPA has classified CKD a non-hazardous waste product provided management standards are followed for groundwater protection and control of fugitive dust releases. CKD should not to be confused with Fly Ash, which is a by-product of burning coal or wood and incineration of other material. Fly ash can contain major oxides and trace metals, depending upon the fuel source, and is considered too hazardous for use as a soil amendment. Using this product is not authorized or endorsed by Ecology or the City. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-94 TABLE D.2.2.9.A CTB/CKD SOIL AMENDMENT BMPS Category of Action Specific Action CTB/CKD Best Management Practices 3. Lay-down Mixing Equipment A. Exposure of CTB/CKD materials to air to be minimized. Delivery tankers shall be set up to place CTB/CKD directly into spreading trucks or equipment. B. CTB/CKD operations are only allowed during daylight hours. C. Tarps or dust bags will be used over the discharge truck hose at unloading to prevent dust particles for becoming airborne. D. Unloading will occur at the lowest possible pump pressure. E. Unloading and mixing will be avoided on high wind days. PSAPCA Section 9.15 prohibits visible emissions of fugitive dust. F. CTB/CKD to be placed on ground by large wheeled spreaders designed for this purpose capable of measuring application. G. When spreading CTB/CKD it shall be kept 2–3 feet away from untreated areas boundaries to prevent the material from migration and contaminating outside the treatment zone. H. Treatment area will be kept damp/wet at all times CTB/CKD is being spread and mixed. Skirting around applicator/spreader and mixer is required to minimize CTB/CKD dust. I. CTB/CKD is to be roto-tilled into soil immediately after being spread onto soils and shall be done with a skirted tiller. J. Direct auguring machine that measures, spreads, and mixes CTB/CKD in one operation is preferred. K. Compaction will be complete within 2 hours after CTB/CKD application. 4. Site Management Work Progress and Weather Conditions A. Dust suppression by use of water trucks shall be used on areas where work on dry soil is performed and potential airborne contamination may occur. B. The volume of CTB/CKD allowed on site will be limited to the amount that can be used within a normal workday. Every effort will be made to forecast the daily delivery rate to match the daily onsite use rate. C. CTB/CKD will not be added to soils at a rate that exceeds the ability of onsite resources to immediately commence mixing and compacting. D. No work will occur in rain heavier than drizzle, or under drizzle that exceeds 6 hours duration, or under any rainfall which generates runoff from the areas being worked. E. Should the weather change to stop the application, remaining CTB/CKD will be covered and contained to prevent stormwater from entering storage containment, and causing runoff. F. All vehicles and equipment leaving the treatment area/site must be cleaned/washed to prevent CTB/CKD from leaving site. Wash water will be contained and treated as needed. G. CTB/CKD contact water in the wheel wash will be removed from the site via a Vactor truck for transport to an approved off-site treatment or disposal facility in accordance with all federal, state, and local laws and regulations; or, if permitted, to the sanitary sewer system. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-95 TABLE D.2.2.9.A CTB/CKD SOIL AMENDMENT BMPS Category of Action Specific Action CTB/CKD Best Management Practices 5. Surface Water Collection A. Surface runoff from the treated areas is to be collected and stored in onsite sealed treatment tanks. B. A rigid schedule of TESC inspection, maintenance, and drainage controls will be maintained. C. Temporarily plugging and using detention facilities is not allowed as a storage practice. D. Runoff from compacted areas amended with CTB/CKD will be directed to previously sealed tank(s) until pH levels of water are verified to be within acceptable background water limits. No uncontrolled discharge or infiltration from the sealed tank(s) will be allowed. E. Drainage from areas amended with CTB/CKD within the past 72 hours will be prevented from co-mingling with any other project drainage. 6. Discharge Compliance Applicable Regulations A. Any and all discharges from this site will be in compliance with all applicable federal, state, and local laws and regulations pertaining to health and safety, water, air, waste, and wildlife, including the Federal Clean Water Act, Clean Air Act, and Endangered Species Act. Laboratory analysis of water is required prior to discharge to verify compliance. B. No infiltration is allowed to occur if pH readings are above 8.5 standard pH units, or below 6.5 standard pH units. C. A pH meter must be used to determine levels. pH meter is to be calibrated following proper QA/QC procedures. Fresh buffers are to be available to re-calibrate as needed. D. A log of turbidity and pH readings will be kept on site for inspection. E. All treatment of water must be directed, bench tested, monitored and verified by a qualified water quality specialist. F. Treated area water runoff shall not enter the permanent stormwater system. G. Stormwater drainage system within treatment area is to be cleaned out prior to use for regular water runoff conveyance from untreated areas. Water from cleanout is to be tested and treated following the approved treatment criteria. SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-96 TABLE D.2.2.9.A CTB/CKD SOIL AMENDMENT BMPS Category of Action Specific Action CTB/CKD Best Management Practices 7. Natural Treatment and Discharge A. The preferred method of disposal of the treatment water will be discharge to the sanitary sewer, provided a permit is obtained to do so. B. If infiltration is proposed, the area of infiltration is to be identified, capacity confirmed, and a contingency discharge plan in place in the event facilities fail to infiltrate. C. For infiltration, pH limits shall be strictly adhered to. D. If a permit to discharge to the sanitary sewer is not obtained, a National Pollutant Discharge Elimination System (NPDES) discharge permit is required from Ecology. The retention volume of the lined pond(s) will also be increased to ensure complete control of the retained volume. Monitoring, bench testing, and controlled discharge rates, with prior approval by Ecology, would be needed prior to discharge to an approved off-site surface drainage system. Sites that currently have NPDES permits will need to amend permit prior to discharge to cover this action. City approval is still required. E. Per RMC 4-6-030, discharges into receiving drainage systems shall not have acid or basic pH levels. F. Sealed storage tanks shall be used to reduce turbidity and pH before discharge. 8. Chemical Treatment A. Carbon dioxide sparging (dry ice pellets) may be used as the chemical treatment agent to reduce the water pH. B. Any means of water treatment to reduce pH will require an NPDES discharge permit from Ecology. Permit would only be granted after bench testing performed by an independent qualified party. C. Active mixing will cease if the residual retention water volume falls below the ability to treat and properly dispose of contact storm water. D. Discharge would only occur after the approval of Ecology, following bench testing and consultation with Ecology. E. All materials for chemical treatment will be on site and property stored, during all phases of CTB/CKD treatment. 9. Water Quality Monitoring A. Turbidity and pH will be monitored on a twice-daily basis, prior to operations and immediately upon ceasing operations, and these measurements will be recorded. Monitoring will also occur immediately after any storm event of ½ inch in 24 hours, or water migration to the retention pond(s), and the measurements recorded. If the pH approaches 8.0, monitoring frequency will increase. B. Turbidity and pH monitoring will occur in all treatment facilities, stormwater detention facilities, infiltration areas (if infiltration is used), and in all surface water areas adjacent to site where stormwater potentially discharges. Additional upstream surface water sites will be established to determine background levels of turbidity and pH. C. All water quality monitoring data will be conducted and evaluated by an independent, qualified party and conducted using professionally supportable test protocols and QA/QC procedures. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-97 TABLE D.2.2.9.A CTB/CKD SOIL AMENDMENT BMPS Category of Action Specific Action CTB/CKD Best Management Practices 10. Reporting Ecology and CED A. All water quality monitoring data will be included in weekly CED TESC reports to CED, and in weekly NPDES reports to Ecology. B. All work, testing, and monitoring associated with the application of CTB/CKD shall be observed by engineer. The engineer shall prepare and submit a report to the assigned CED project inspector indicating BMPs were/were not being met. C. Copies of all reports and logs will be available on site during the soil and surface runoff treatment activities. Other elements to consider: 11. Water Quality – Soils Source Controls A. There may be very small amounts of concrete washout produced onsite as a result of construction of erosion control measures during reclamation. Concrete washout, if any, would be retained in a lined enclosure of at least 6-ml Visqueen or plastic sheeting, with no outlet. The washout retention enclosure would be isolated and separate from any CTB/CKD area runoff. Contents of the lined concrete washout enclosure will be removed from the site via a Vactor truck for disposal in an approved off-site treatment or disposal facility in accordance with all federal, state, and local laws and regulations. Signed trip tickets, as proof of proper disposal, will be provided to Ecology and CED. 12. Water Quality – pH Cover Measures A. Areas amended with CTB/CKD for compaction after CTB/CKD addition will be covered with plastic or Visqueen sheeting, or other impervious material by the end of each working day. B. Temporary cover will be maintained over all compacted areas amended with CTB/CKD until testing confirms that pH levels are stabilized to background measurements. [Note: Curing to avoid pH effects has no relationship to the rate at which material can be compacted in multiple lifts. Compaction will commence immediately after application and mixing, and multiple lifts will occur as quickly as each lift is compacted and ready to accept the next.] C. Should weather conditions prevent mixing, any unmixed CTB/CKD remaining on site will be enclosed in a sealed containment, such as portable silo, or removed from site. Processing Requirements for Use of High pH Soil Amendments on Construction Sites10 Purpose This section establishes procedures for implementing BMPs when using high pH soil amendments on construction sites. See Table D.2.2.9.A for a description of the BMPs. This section outlines an expedited review process and typical approval conditions that will allow contractors and builders to use soil amendments without impacting water quality. Additional BMPs may be required based upon site specific conditions that may warrant more protection. This policy is limited to those amendments, defined below, commonly known to add stability to sloppy soil conditions but which can alter water runoff quality. Authority: RMC 4-6-030(J) prohibits discharges of polluted or contaminated water into surface or storm water drainage systems. The purpose of this statute is to protect surface and ground water by regulating the discharge of potentially contaminated surface water. If soil amendments are proposed with an initial application, an environmental review is required, under SEPA, which assesses impacts, provides public input and mitigated conditions for its use. 10 Excerpted from the King County Stormwater Pollution Prevention Manual (SPPM), BMP Info Sheet #11 SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-98 The City of Renton also requires an engineered design for use of a soil amendment on road surfaces or around drainage systems (see Appendix C). The design may incorporate a thorough assessment of soil composition and laboratory analysis. The SWDM authorizes CED to adopt BMPs for the control and protection of surface water. Currently, for all sites, the BMPs established in this policy are the minimum standards that shall be applied. Procedure An applicant may apply for use of soil amendments allowed under this policy anytime during the permit application review or after the permit has been issued and site construction is underway. After making a submittal to CED, the applicant may receive approval conditions. Conditions may vary from site to site, but typically will include many of the BMPs included in this policy. Applicants should identify any use of soil amendments as early in the process as possible to avoid delays in obtaining approval for use during the construction phase. If a site has known soil and water conditions that might make work during rainy periods difficult, they may want to plan to use soil amendments on their site. Obviously, if this issue is addressed at the permit review phase, implementation in the field can occur without delay. However, because of the potential risks of surface water pollution discharge and required treatment, an environmental assessment will be necessary before conditions for use can be established. Limitations This policy applies to the intended use of soil amendments in areas that will be covered by impervious surfaces. For areas not covered by impervious surfaces, additional reviews, study, and BMPs may be required. In addition, alterations to original approved use plans will require a resubmittal for approval. Approval for the use of the soil amendments can only occur by strictly following the procedures contained herein and not by any other approval obtained from CED. Submittal Requirements To obtain approval for the use of soil amendments allowed under this policy, the applicant shall prepare a submittal package to CED that includes the following: • Letter to CED requesting use of soil amendments at a construction site allowed under this policy. • Document or letter attachment that identifies source of materials and description of mixing and laydown process, plan for disposal of treated contact water, sanitary sewer permits and/or BMPs, and special precautions proposed to prevent the contamination of surface or stormwater drainage systems, other than ‘sealed’ drainage systems. • Site Plan: Show a site plan map which: 1) Shows overall grading plan showing existing and proposed contours. 2) Identifies sensitive areas and permanent or temporary drainage facilities. 3) Identifies areas that soil amendment is planned. 4) Shows depths of application and percent of amendment to be used. 5) Shows location of special wheel wash facility. 6) Shows location of collection and conveyance swales or pipes for contact water. 7) Shows location of sealed storage/treatment tanks or temporary ponds (fully lined). 8) Identifies any discharge point from the site into natural drainage systems. 9) Includes soil log locations that identify seasonal high groundwater areas. • Report and analysis of engineering mix design which includes depths of application and percent of amendment usage. • For proposals that use CKD and CKD additive, provide analysis of source material for soluble contaminants. Include a description of fuel source. D.2.2 SWPPS MEASURES 2017 City of Renton Surface Water Design Manual 12/12/2016 D-99 • Monitoring criteria, including locations for pH and turbidity testing. • Provide contingency plan should use of soil amendment and site and weather conditions result in polluted or contact water entering natural drainage systems. • Provide contact information or water quality specialist assigned to monitor application of soil amendments and BMPs. If the project is under construction, the applicant shall contact the CED inspector assigned to the project to initiate a review for compliance with the BMPs and requirements herein. Otherwise contact the planner or engineer assigned to review the permit or land use application. Review and Approval Once the review has been completed, the applicant shall be notified by letter which stipulates the conditions of approval. Prior to authorizing the use of soil amendments at the site, the applicant shall provide a special restoration financial guarantee cash deposit in the amount as determined by the existing, established processes. Note: It remains the applicant/contractor’s responsibility to comply with any other applicable state or federal regulations such as use of NIOSH respiratory protection, safety goggles, gloves and protective clothing whenever using hazardous materials. Applicable Standards Typically, all proposals using soil amendments shall have these conditions as standard requirements: 1. Prior to any application of CKD/CTB, the general contract shall hold a preconstruction meeting with the assigned CED inspector at least 3 working days in advance. 2. CKD will not be permitted for use in areas adjacent to or in proximity to wetlands and streams areas. CTB may or may not be permitted in these areas. 3. Areas not covered by impervious surfaces: • CKD will not be permitted in areas that will not be covered by impervious surfaces. • If CTB is proposed in these areas, an analysis of whether or not the soil amendment will change the post-development runoff characteristics and the permanent stormwater facilities were sized appropriately shall be submitted for review. Use of CTB in areas not permanently covered by impervious surface may require re-sizing of the permanent stormwater facilities. 4. If CKD is proposed, the contractor shall provide mill certificates verifying the product composition. The contractor/developer must be prepared to follow BMPs during and after soil treatment and be prepared to treat runoff from the treatment area(s) immediately. All stormwater collection systems must be in place and all equipment (pH meters, dry ice, etc.) must be onsite. 5. Collection of stormwater (see BMP #5 in Table D.2.2.9.A): • Stormwater from the application area shall be kept separate from and prevented from comingling with uncontaminated stormwater. • During the application of CKD/CTB, stormwater runoff shall be collected in temporary collection systems and shall not be allowed to enter the permanent facilities. Permanent drainage systems shall be capped to prevent contact stormwater from entering the inlets of the catch basins. Stormwater from the application area shall not be collected in the temporary/permanent detention ponds, even if the underlying soils are ‘impermeable.’ 6. Treatment: If necessary, pH adjustment shall be done in the collection tanks or temporary ponds and not in the permanent detention ponds. 7. Disposal options: The proposal to use CKD/CTB must contain a disposal plan that may include one or a combination of sanitary sewer or approved offsite disposal. Treated contact water may be discharged to the sanitary sewer if authorizations are obtained from the King County and the City of Renton. All discharge conditions (e.g., pH, settleable solids) must be followed. If a sanitary sewer is not available at the site, contact water may be transported offsite to an approved site for disposal and proof of SECTION D.2 GENERAL CSWPP REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual D-100 proper disposal must be submitted to the City. All authorizations for disposal shall be obtained prior to CKD/CTB application. • Infiltration: Depending on the site conditions, pH-adjusted stormwater may be infiltrated. Prior to infiltration, pH must be between 6.5 and 8.5. • Surface Water: Contact water from the application area shall not be discharged to surface waters, even if treatment has adjusted the pH. 8. Emergency backup plan: An emergency backup plan must be prepared and ready to implement to handle large quantities of stormwater. 9. Monitoring shall be conducted to determine that contact stormwater is not leaving the site. Offsite monitoring shall also be conducted to identify impacts to adjacent water bodies. Bonding may be required to cover mitigation of impacts and restoration. 10. A soils specialist will establish the mixing percentage for onsite soils. Soil amendments will never occur in excess of the ability of the onsite equipment and resources to meet all BMP requirements. 11. For sites one acre or larger, a Construction Stormwater General permit must be obtained from Ecology. Construction Stormwater General permits and ‘Stormwater Pollution Prevention Plans (SWPPPs) must be amended and the use of CKD/CTB must be approved by Ecology prior to application. The contractor/developer shall comply will all federal, state, and local regulations. A health and safety plan may be required for the protection of CED inspectors. Additional BMPs may be applicable depending on mix design, proximity of wetlands or streams (e.g., within 300 feet of class/type I and 100 feet or less for other types) and site conditions. D.2.2.10 MAINTAIN PROTECTIVE BMPS Pollutant protection measures shall be maintained to ensure continued performance of their intended function. Reporting and documentation shall be kept current and made available to CED as indicated. Purpose: The purpose of maintaining protective BMPs is to provide effective pollutant protection when and where required by the plan and the project, and to provide timely and relevant project information. When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, continuously during operation, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Documentation shall be kept current per specific BMP requirements. Measures to Use: 1. Maintain and repair all pollutant control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Maintain and repair storage locations for equipment and materials associated with BMP processes. Conduct materials disposal in compliance with City requirements. 3. As required, provide current reporting and performance documentation at an accessible location for the site inspector and other CED staff. 4. Remove all temporary pollutant control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. D.2.2.11 MANAGE THE PROJECT SWPPP requirements shall be implemented and managed as part of the overall CSWPP plan. Concrete construction and its impacts are primary among pollutant concerns on site development projects. Fueling operations and materials containment of treatment chemicals and other project materials are also typical Technical Information Report PSE Energize Eastside – Renton Segment | December 29, 2020 Appendix B – Critical Areas Report R E N T O N C R I T I C A L A R E A S R E P O R T ( I n c l u d i n g W e t l a n d A s s e s s m e n t , S t r e a m S t u d y , a n d W i l d l i f e / H a b i t a t A s s e s s m e n t ) Puget Sound Energy – Energize Eastside Project Prepared for: Bradley Strauch PSE Energize Eastside 355 110th Avenue NE Bellevue, WA 98004 Prepared by: January 2018 The Watershed Company Reference Number: 111103.8 The Watershed Company Contact Person: Jennifer Creveling, Senior Biologist Or Clover McIngalls, Environmental Planner Cite this document as: The Watershed Company. January 2018. City of Renton Critical Areas Report: Puget Sound Energy – Energize Eastside Project. Prepared for PSE. The Watershed Company January 2018 i T ABLE OF C ONTENTS Page # 1 Executive Summary............................................................................ 1 2 Introduction and Project Description ............................................... 2 3 Methods ............................................................................................... 4 3.1 Study Area ........................................................................................................... 5 3.2 Data Compilation ................................................................................................. 5 3.3 Project Element Construction – Potential Impacts ............................................... 6 Pole Replacement ............................................................................................... 6 Access routes ...................................................................................................... 8 Stringing Sites ...................................................................................................... 9 Vegetation Management...................................................................................... 9 3.4 Critical Areas Impact Analysis............................................................................ 10 3.5 Limitations ......................................................................................................... 11 4 Existing Conditions .......................................................................... 12 4.1 Site Location ...................................................................................................... 12 4.2 Site Description ................................................................................................. 12 4.3 Critical Areas ..................................................................................................... 13 Wetlands ............................................................................................................ 13 Streams and Lakes ............................................................................................ 14 Habitat Conservation Areas ............................................................................... 15 Flood Hazard Areas ........................................................................................... 22 Geologic Hazard Areas...................................................................................... 23 Wellhead Protection Areas ................................................................................ 25 4.4 Shorelines of the State ...................................................................................... 26 5 Regulations ....................................................................................... 27 5.1 Local Regulations .............................................................................................. 27 Wetlands and Streams ...................................................................................... 28 Geologic Hazard Areas...................................................................................... 30 Flood Hazard Areas ........................................................................................... 31 Habitat Conservation Areas ............................................................................... 31 Wellhead Protection Areas ................................................................................ 32 5.2 Alteration of Critical Areas and Buffers .............................................................. 32 Wetland and Stream Buffers ............................................................................. 32 Geologic Hazard Areas and Associated Buffers ............................................... 34 6 Mitigation Sequencing ..................................................................... 34 7 Unavoidable Project Impacts .......................................................... 35 7.1 Critical Area Impacts .......................................................................................... 39 Wetland and Stream Buffer Impacts .................................................................. 39 PSE Energize Eastside Project Renton Critical Areas Report ii Geologic Hazard Area Impacts and Associated Buffer Impacts ....................... 41 Wellhead Protection Area Impacts .................................................................... 42 Habitat Conservation Area Impacts ................................................................... 43 7.2 Functional Lift Analysis ...................................................................................... 43 May Creek Sub-basin ........................................................................................ 46 Lower Cedar River Sub-basin ........................................................................... 47 7.3 Cumulative Impacts ........................................................................................... 49 8 Mitigation ........................................................................................... 51 8.1 Wetland and Stream Buffer Mitigation Approach ............................................... 51 8.2 Wetland and Stream Buffer Mitigation Plan ....................................................... 52 8.3 Geologic Hazard Area Mitigation ....................................................................... 54 9 Code Compliance ............................................................................. 55 9.1 Wetlands and Streams ...................................................................................... 56 9.2 Geologic Hazard Areas ...................................................................................... 59 9.3 Wellhead protection areas ................................................................................. 60 9.4 Habitat conservation areas ................................................................................ 60 10 Disclaimer .......................................................................................... 61 Appendix A Critical Area Assessment Maps Appendix B Delineation Study Appendix C 2017 Delineation Study Update Appendix D Detailed CAIA Methodology Appendix E Geologic Hazards Report Appendix F Riverview Park Mitigation Plan Appendix G Conceptual Honey Dew Creek Mitigation Plan The Watershed Company January 2018 iii L IST OF F IGURES Figure 1. Map of Energize Eastside Project route in Renton and limits of the Critical Area Impact Assessment. ................................................................................. 4 L IST OF T ABLES Table 1. PSE construction scenarios. .............................................................................. 7 Table 2. State-listed wildlife species, excluding those listed as federally endangered and threatened. ............................................................................................. 16 Table 3. Summary of wetland critical area classifications and standard buffer widths. ... 28 Table 4. Summary of stream critical area classifications and standard buffer widths. .... 29 Table 5. Summary of geologic hazard area buffer requirements.................................... 31 Table 6. Matrix used for determining impact types based upon long-term condition of proposed activities and existing land cover types in critical areas and associated buffers. ................................................................................. 38 Table 7. Wetland and stream buffer impacts by wetland and/or stream feature and sub- basin. ..................................................................................................... 40 Table 8. Geologic hazard area impacts associated with pole replacement in Project area. ............................................................................................................... 41 Table 9. Vegetation conversion impacts to geologic hazard areas in the Project area. .. 42 Table 10. Actions within wellhead protection areas in the Project area. ......................... 42 Table 11. Descriptions of general impact area conditions and proposed changes. ........ 45 Table 12. Calculation of mitigation needs for wetland and stream functioning buffer impacts. ................................................................................................. 53 The Watershed Company January 2018 1 C ITY OF R ENTON C RITICAL A REAS R EPORT PUGET SOUND ENERGY – ENERGIZE E ASTSIDE 1 EXECUTIVE SUMMARY PSE’s Energize Eastside Project (the Project) proposes to upgrade existing transmission lines in the city of Renton in order to increase transmission system capacity to 230kV power. The Project is needed to address electrical system deficiencies identified during federally-required planning studies and to improve electrical supply and reliability to Eastside communities, including Renton, now and in the future. Regulated critical areas present in the Project area include wetlands, streams, and associated buffers; habitat conservation areas; flood hazard areas; geologic hazard areas (i.e., steep slopes, landslide hazards, erosion hazards, seismic hazards, and coal mine hazards); and wellhead protection areas. A portion of the Project area also lies within the shoreline jurisdiction of the Cedar River. The Project was designed to avoid and minimize impacts to critical areas. No new poles are proposed in wetlands, streams or stream buffers or seismic hazard areas. One new pole is proposed in a wetland buffer and three existing Lake Tradition Line poles in wetland buffer will be replaced with new, larger poles in the same locations, resulting in a net increase in pole footprint at those locations. New poles are also proposed in erosion hazard areas, landslide hazard areas, steep slope hazard areas, coal mine hazard areas, habitat conservation areas and wellhead protection areas. Vegetation conversion impacts are also proposed in these areas, as well as in stream and wetland buffers. In wetland buffers, permanent impacts (i.e., poles) are limited to one new Energize Eastside pole and three Lake Tradition replacement poles. Two existing poles will be removed from and replaced outside of wetland and stream buffer resulting in a net increase of only 68 square feet of permanent impact. Vegetation community conversion impacts in wetland and stream buffers total 18,786 square feet and 20,064 square feet of temporary disturbance will occur. Impacts will be minimized by utilizing the existing transmission line corridor, limiting disturbance and implementing best management practices (BMPs) when PSE Energize Eastside Project Renton Critical Areas Report 2 working in critical areas, and installing transmission lines between poles with minimal site disturbance. The majority of wetland/stream critical area impacts, which are exclusively buffer impacts from vegetation management (i.e., tree removal), with the exception of one new pole in a wetland buffer and three increased footprints of Lake Tradition Line replacement poles, occur in the Lower Cedar River sub- basin. Impacts within this sub-basin will be mitigated on an areal and functional basis in wetland and stream buffer in the vicinity of the Cedar River pursuant to the Riverview Park Mitigation Plan (Appendix F). Additional impacts occurring to the buffer of Honey Dew Creek within the May Creek sub-basin will be mitigated for in the Honey Dew Creek buffer, pursuant to the Honey Dew Creek Conceptual Mitigation Plan (included as Appendix G). Impacts to geologic hazard areas have been quantitatively assessed and proposed activities have been determined to not significantly affect geologic hazard areas or their associated buffers with implementation of BMPs. This report is intended to support the City of Renton’s critical area review process and to satisfy the requirements of the Renton Municipal Code (RMC) 4- 3-050 – Critical Area Regulations. 2 INTRODUCTION AND PROJECT DESCRIPTION Puget Sound Energy, Inc. (“PSE”) proposes the construction of a new 230 kV to 115 kV substation (Richards Creek Substation in Bellevue) and to upgrade approximately 18 miles of existing 115 kV transmission lines located within an approximately 100-foot wide regional utility corridor to accommodate 230 kV power (collectively “the Project”). The Richards Creek Substation will be built to accommodate the 230kV to 115kV transformer needed to accommodate the transmission line upgrade, which is necessary to address a deficiency in electrical transmission capacity during peak periods. Combined with aggressive conservation, the Project will improve reliability for Eastside communities, including the city of Renton (“Renton” or “City”), and supply the needed electrical capacity for anticipated growth and development on the Eastside. Within Renton, the Project corridor extends north-south for approximately 4 miles (Figure 1). The proposal for the Energize Eastside Project includes the removal of 144 existing poles and installation of 41 new poles. Existing and proposed pole locations are shown on the maps in Appendix A. The Watershed Company January 2018 3 PSE owns and operates an existing 115 kV transmission line between the Talbot Hill substation in Renton and the Lake Tradition substation in Issaquah (Talbot Hill - Lake Tradition #1). To better accommodate the Project, a short section of the Lake Tradition #1 line will “trade” places with one of the Lakeside-Talbot Hill 115 kV lines, which will be rebuilt to 230 kV as part of the Project. This relocation work will take place within PSE’s existing easement near the Shadow Hawk condominiums on parcel #7701590000. (Refer to Appendix A for pole locations.) The work will include replacement of the existing three-pole wood turning structure (115-5) that is situated on the Shadow Hawk property. The 115 kV conductor will then be “jumpered” for one span underneath the new 230kV lines to another replacement three-pole wood structure (115-4). One new two- pole wood structure (115-3) will be added to provide additional wire clearance for the existing 115 kV conductor just east of the corner structures (115-4 and 115- 5). Additionally, two of the existing three-pole wood structures (115-1 and 115-2) north of the Talbot Hill substation on the Talbot Hill – Lake Tradition #1 line will be replaced with similar structures as part of general maintenance and repair due to the poor condition of the existing structures. The existing overhead 115 kV conductors (wires) will remain in place and be reattached to the new and replacement wood pole structures. This work will maintain the existing transmission line corridor and will not require any additional easements. The existing transmission lines are located in PSE’s Sammamish-Lakeside-Talbot transmission line corridor, which was established in the late 1920s and early 1930s. Within the existing utility corridor, the proposed upgraded lines will place poles in generally the same locations as existing poles. In some instances, poles will be moved to accommodate landowner preferences and easement considerations, and to minimize impacts to critical areas. During construction, selective tree removal will occur within the corridor to meet federal vegetation management requirements and PSE standards (see Section 3.3.4 for more information). The purpose of this Critical Areas Report is to document critical area impacts that are expected to occur as a result of the Project in Renton and how the Project proposes to compensate for those impacts. This report fulfills the criteria of RMC specific to stream and wetland buffer modifications and presents a detailed discussion of the habitat and vegetation on-site and how the Project can be implemented with no net loss of on-site or off-site critical area functions and values. PSE Energize Eastside Project Renton Critical Areas Report 4 Figure 1. Map of Energize Eastside Project route in Renton and limits of the Critical Area Impact Assessment. 3 METHODS A Critical Areas Impact Assessment (“CAIA”) was conducted for the Project in Renton. The analysis combined GIS-based assessment with field-verified conditions and evaluated proposed project elements in relation to existing land cover types and regulated critical areas. The location and type of each proposed activity was used to determine impacts and mitigation needs and is based upon preliminary site plans provided by PSE (on 6/30/17 with updates through 11/06/17). A detailed description of the CAIA process and methods is provided in Appendix D. The Watershed Company January 2018 5 3.1 Study Area For the purposes of this report the study area is limited to a segment of the proposed Energize Eastside corridor within Renton. The Renton corridor runs from the north Renton city limits south of SE 95th Way to the existing Talbot Hill substation in the vicinity of Beacon Way S, a distance of approximately 4 miles. The study area in Renton is limited to the area within the boundaries of an approximately 100-foot wide regional utility corridor, except between the Talbot Hill substation and Shadow Hawk neighborhood where the study area was widened to capture additional area based on refined design parameters. The study area is depicted by the red line on the attached maps (Appendix A). 3.2 Data Compilation Critical areas evaluated as a part of the analysis include wetlands, streams and lakes, habitat conservation areas, flood hazard areas, geologic hazard areas (including steep slopes, landslide hazards, erosion hazards, seismic hazards, and coal mine hazards, wellhead protection areas, shorelines, and any associated critical area buffers. To facilitate the CAIA, the following data were compiled and reviewed: tree inventory, wetland and stream surveys, and publically available data. Tree Inventory Existing trees with the potential to reach a height greater than 15 feet located in the Project area corridor was inventoried between March and November 2015 and September and October of 2017. Tree inventory methodology and results are available in the City of Renton Tree Inventory Report: Puget Sound Energy – Energize Eastside Project (The Watershed Company 2016b). Tree data used in this CAIA were obtained and compiled from surveys, GPS, and digitization using high- resolution imagery. Wetland and Stream Surveys Wetlands and streams were originally delineated and classified within a defined study area which generally consisted of a 100-foot wide corridor defined by an established PSE easement, between March and October 2015. This delineation is documented in the City of Renton Critical Areas Delineation Report: Puget Sound Energy – Energize Eastside Project (The Watershed Company 2016a) included as Appendix B. As the Project design became more refined, the need for additional delineation was identified in the vicinity of the Cedar River and south of the original study area corridor between the Talbot Hill substation and Shadow Hawk neighborhood. These areas were delineated between September and October of 2017 and are documented in PSE Energize Eastside-2017 Additional Wetland and Stream Delineation in Renton (The Watershed Company 2017) included as Appendix C of this report. Wetland and stream data were compiled from field generated GPS data and are limited to the study areas defined in the PSE Energize Eastside Project Renton Critical Areas Report 6 delineation documentation. Delineation study methodology is detailed in the previously-referenced reports. Publicly Available Data Publicly available Renton GIS data were utilized for mapping the following critical areas in Renton: landslide hazard areas, erosion hazard areas, steep slope hazard areas, coal mine hazard areas, seismic hazard areas, and flood hazard areas. Data used to map impervious surfaces and development include the King County Impervious and Impacted Surface data (King County 2009), supplemented with land survey data and high-resolution aerial photography provided by PSE. Additional detail about the data inventory elements and methodology are available in Appendix D. 3.3 Project Element Construction – Potential Impacts Project elements that have the potential to impact critical areas are defined in this section and include the following: - Pole replacement: o removal of old poles o installation of new poles pole buffer (6-foot radius outside of pole footprint), pole construction work area (varies by pole type, see description below); - Access routes (approximately 20 feet wide); - Stringing sites; and - Vegetation management requirements. Pole Replacement Existing H-frames (consisting of 2 or 3 poles) will be replaced with new monopoles (i.e., a single pole). Existing pole sizes have been presumed to be approximately 2.75 feet in diameter on average. The diameter of new poles ranges from 3-6 feet. In general, relocation activities will occur in close proximity to the existing H-frames, but some of the replacement poles will be moved to accommodate landowner preferences, due to easement considerations, and to minimize impacts to critical areas. To conduct this work, PSE created construction scenarios specific to the type of structure being installed. Table 1 below describes the scenarios applicable to the Project. These scenarios provide assumptions used to assess impacts. The Watershed Company January 2018 7 Table 1. PSE construction scenarios. Description Scenario No Critical or Recreation Area Present Direct embed-single pole Temporary work area is generally 2,500 square feet Create hole (hole will be larger than diameter of the new pole) New pole and backfill delivered to site Place pole in hole and backfill annulus Stabilize site A A1 Foundation-single pole Temporary work area is generally 5,000 square feet Create hole (hole will be slightly larger to accommodate foundation installation) New pole and foundation materials delivered to site Build foundation and install pole Stabilize site C C1 Critical or Recreation Area Present Direct embed-single pole Establish construction buffer from critical area using appropriate BMPs Temporary work area is generally 2,500 square feet Create hole (hole will be larger than diameter of the new pole) New pole and backfill delivered to site Place pole in hole and backfill annulus Stabilize site A A2 Foundation-single pole Establish construction buffer from critical area using appropriate BMPs Temporary work area is generally 5,000 square feet Create hole (hole will be slightly larger to accommodate foundation installation) New pole and foundation materials delivered to site Build foundation and install pole Stabilize site C C2 While the work area for each pole type is defined as a consistent size to be conservative, the shape of the disturbed area will vary depending on the presence of critical areas or other sensitive features in the Project corridor. During construction, critical areas and other sensitive features will be excluded from the disturbance area where possible. Pole replacement will potentially result in three types of impacts: permanent, vegetation conversion, and temporary. PSE Energize Eastside Project Renton Critical Areas Report 8 Permanent impacts will be associated with the installation of new poles, which will have a base diameter ranging from 3 feet to 6 feet depending on the pole type (direct imbed, or new foundation which has a larger base diameter). However, some existing poles (which currently contribute to permanent fill) will be removed from critical areas and this was taken into account for wetland and stream buffer impact calculations. Vegetation conversion impacts will be associated with the removal of incompatible transmission line vegetation. The transmission line corridor, experiences routine vegetation management which will continue. All vegetation in the wire zone and managed right-of-way (ROW) portions of the transmission line corridor, when mature, will be fifteen feet or less (unless the topography allows for at least a 20-foot clearance between vegetation and the lines). During typical inspections and maintenance of the poles, vegetation is routinely disturbed; as such, no trees of any size will grow within 6 feet of the new poles. Where pole construction work areas and pole buffer areas do not require the removal of trees, the resulting impacts will be temporary. The majority of pole construction work area and pole buffer impacts are expected to be temporary due to the existing use and management of the corridor (i.e., lack of trees) and consideration that existing groundcover will be restored or regenerate on its own within one growing season. After construction, the temporarily disturbed areas will be re-vegetated and left to return their natural state or enhanced. BMPs will be used to minimize impacts resulting from pole replacement activities. In critical areas or buffers, mats will be placed over existing vegetation where possible. Typically, crushed vegetation rebounds within one growing season resulting in only temporary impacts to vegetation. Post-construction, all disturbed areas will be re-vegetated, if necessary, and left to return to their natural state. The impacts are further analyzed and quantified in Section 7 of this report. Access routes Access to pole removal and construction sites in critical areas will generally occur using existing, partially vegetated access (established during original construction and re-used over time to maintain the corridor). BMPs will be used to minimize ground disturbance in these areas, and in new areas of access. In critical areas or buffers, mats will be placed over existing vegetation where possible. Typically, crushed vegetation rebounds within one growing season resulting in only temporary impacts to vegetation. Where access route alignment requires tree removal, impacts will be characterized as conversion. Post- The Watershed Company January 2018 9 construction, all disturbed areas will be re-vegetated, if necessary, and left to return to their natural state in compliance with vegetation management requirements. Based on the existing conditions, proposed construction BMPs, and post-construction methods, disturbance associated with access in the transmission corridor will predominantly be temporary. Stringing Sites In order to replace the transmission conductor, stringing and tensioning equipment will be staged near new steel poles at specific locations along the corridor in preparation for the stringing of new wire. The disturbance area associated with the equipment and materials to restring the conductor wire will be outside of wetlands and streams. In other critical areas and buffers, mats will be placed over existing vegetation where possible to allow access to poles for stringing activities. Typically, crushed vegetation rebounds within one growing season resulting in only temporary impacts to vegetation. Tree removal activities necessary for the stringing of new wire (in the wire zone) will be performed in a manner to minimize impacts to underlying shrubs, groundcover and other trees, and with minimal disturbance to soil. Various techniques will be utilized to string the wire to minimize surface disturbance (i.e., shooting the wire past obstacles, pulling it along established guide wire, helicopter, etc.). For this analysis, stringing sites have been identified as point locations and not polygons (Appendix A). However, each stringing site will cause approximately 7,500 square feet of disturbance. Similar to pole construction work areas, the shape of the stringing site will depend upon the presence of adjacent critical areas, existing land conditions, and area needed for equipment staging based on the necessary angle needed to string the conductor. In many areas, this disturbance will overlap with various impacts quantified for proposed access, pole installation, and vegetation management. While impacts have not been quantified for stringing sites, stringing sites are expected to largely overlap other work areas and are not expected to require additional tree removal. Any additional impacts resulting from stringing sites, not already quantified in Section 7 through other Project elements, will be temporary in nature. Stringing sites will not result in permanent impacts to critical areas. Temporary impact areas will also be avoided to the extent feasible. Unavoidable temporary impact areas will be re-vegetated and left to return to their natural state or enhanced following construction. Vegetation Management Vegetation in the existing corridor is routinely managed. The corridor was initially disturbed during original construction (including soil compaction associated with construction activities for the line itself and roads, parking lots, subdivisions, trails, and commercial development). Disturbance is regular and PSE Energize Eastside Project Renton Critical Areas Report 10 ongoing due to maintenance and pole replacement activities. With the exception of the Cedar River and Honey Creek areas, the majority of trees in the existing corridor are ornamental and associated with existing residential or commercial property uses. Vegetation in a transmission line corridor that has an operational voltage of more than 200 kV must be managed in compliance with federal requirements. Vegetation management standards vary depending upon the location of vegetation management in relation to transmission wires. These specific locations are defined as follows: Wire Zone – Section of a utility transmission ROW extending to 10 feet from the outside transmission wire(s). Vegetation with a mature height of 15 feet or less is allowed in this zone. Managed ROW – The section of a transmission line ROW that extends 6 feet outside of the wire zone. Vegetation with a mature height of 15 feet or less is allowed in this zone. Legal ROW – The full width of the easement. While vegetation maintenance is permitted within the full extent of the legal ROW, based on communication with PSE, only a portion of the legal ROW is intended to be maintained; this area is described as the maintained legal ROW and generally extends 10 feet from the edge of the managed ROW. Maximum height of mature vegetation between the managed ROW and legal ROW is dependent upon tree species, tree health, and distance from the wires. Consistent with federal standards, vegetation in the wire zone must have a mature height of no greater than 15 feet, unless the topographic change is sufficient to allow a 20-foot vertical clearance between the power lines and the mature height of trees under the power lines. The same vegetation requirement was applied to the managed ROW zone. The legal ROW is composed of existing and proposed easements; its width is approximately 100 feet through Renton. The area outside of the managed ROW, but still within the legal ROW, is also subject to select clearing of trees that pose a risk of damaging the lines. To facilitate the CAIA, in the maintained legal ROW, a maximum mature tree height of 70 feet was presumed. However, existing trees greater than 70 feet, or with a mature height of greater than 70 feet will not necessarily be removed. Impacts resulting from required vegetation management are characterized as conversion in Section 7 of this report. 3.4 Critical Areas Impact Analysis The CAIA was conducted by placing tree points/polygons and critical area polygons on a georeferenced base map and overlaying preliminary site plans to The Watershed Company January 2018 11 determine impacts. Impervious surfaces and other similar areas characterized as developed were removed from wetland and stream buffer areas for this CAIA as non-functioning buffer areas. The resulting functioning wetland and stream buffers are shown in Appendix A. Where Project elements (as discussed in Section 3.3) are located in critical areas or their functioning buffers, impacts are quantified based on area (square footage [SF] of impact). Impact results were generated based upon the expected long- term condition of the area compared to the existing condition and include permanent impacts, impacts that result in vegetation conversion, temporary impacts, and activities that result in no change or no impact (see Section 7). For more detailed methodology on the CAIA, refer to Appendix D. Impacts associated with new or replaced Lake Tradition Line poles were analyzed differently than the rest of the Project elements as the adjustments made to the Lake Tradition line to accommodate the Project entail different elements and impacts than the actions associated with the Project. Work associated with the Lake Tradition line is restricted to one area of the project corridor, affecting approximate five adjacent spans. Work includes resetting existing poles, adding new poles, and rehanging lines on existing poles. Due to the limited work and the utilization of existing poles, no vegetation impacts due to conflicts between wire height and tree height are anticipated. Therefore, for new or replaced poles along the Lake Tradition line, tree removal impacts were calculated based solely on proximity to proposed pole work areas. The long-term condition and impact characterization for “pole work area” was consistent with the parameters of the Energize Eastside analysis, as described in Appendix D. 3.5 Limitations The Watershed Company’s technical expertise is specific to wetlands, streams, habitat conservation areas, and shorelines. The geotechnical assessments and interpretation of impacts within geologic hazard areas have been addressed by others and referenced in the report and incorporated as Appendix E. This document represents a point-in-time analysis of the proposed Project, potential impacts, and approach to critical area mitigation. Refinements made as a result of ongoing design are expected to decrease Project impacts moving forward. If design changes result in increased permanent or conversion impacts that cannot be addressed in the proposed preliminary mitigation plan, a Critical Areas Report Addendum will be prepared to address those impacts. PSE Energize Eastside Project Renton Critical Areas Report 12 4 EXISTING CONDITIONS 4.1 Site Location The Renton study area is dominated by urban land uses. The majority of the corridor is zoned residential, commercial, or industrial. Within the residential areas, the corridor passes through several distinct neighborhoods; from north to south, these include Glencoe, Honey Creek Ridge, Sunset, Liberty Ridge, and Shadow Hawk. The largest patch of remaining undeveloped land is located adjacent to the Cedar River and zoned Resource Conservation (RC). The study area corridor is primarily located in the Cedar-Sammamish Watershed (WRIA 8). Within WRIA 8 the Project area lies within three drainage basins. The north end of the study area is within the May Creek basin, the middle portion is within the East Lake Washington basin, and the southern portion is in the Lower Cedar River drainage basin. No wetlands or streams were identified in the East Lake Washington basin. At the southern end of the corridor, near the Talbot Hill substation, the study area drains into the Black River basin of the Duwamish- Green Watershed (WRIA 9). The study area corridor in the Renton is located in Township 23N, Range 05E, and Sections 4, 9, 16, 20, and 21. 4.2 Site Description When the corridor was constructed in the late 1920s and early 1930s, the entire corridor was cleared. Construction activities resulted in a compacted subsurface in those areas where the poles were installed. Since that time, the corridor has been continually maintained by PSE through easement rights. Using existing access routes/paths, poles have been replaced and vegetation has been managed. To do so, vehicles and equipment (such as cranes) have been used in the corridor. Over time, development has occurred adjacent to and within the corridor, including residential development, roads, parking lots, commercial development, and the establishment of trails (using overgrown access routes). The Talbot Hill area is utilized by an extensive number of co-located critical utilities. PSE owns and operates the Talbot Hill substation located on parcel #2023059003 into which nine existing 115 kV transmission lines connect, as well as the existing PSE-owned Talbot Hill–Berrydale #3 230 kV transmission line. Two of the 115 kV transmission lines will be upgraded to 230 kV as part of the Project. Bonneville Power Administration (BPA) owns and operates the BPA Maple Valley substation located immediately east of the Talbot Hill substation on adjacent parcel #023059062 into which one PSE-owned 230 kV, two BPA- owned 230 kV, and two BPA-owned 500 kV lines connect. Two 230 kV lines connect the Talbot Hill substation to the BPA Maple Valley substation. Seattle City Light (SCL) owns and operates two 230 kV transmission lines in the area, The Watershed Company January 2018 13 one of which connects to the Talbot Hill substation and the other to the BPA Maple Valley substation. Between the two substations on parcel #2023059051, Seattle Public Utilities (SPU) owns and operates three large watermains that transport the primary water supply from the Cedar River Watershed to the City of Seattle. The 20-inch-diameter Olympic Pipeline (OPL) traverses west to east within several easements north of the PSE and BPA substations within the transmission line corridor utilized by PSE, BPA, and SCL. Within this utility corridor, PSE and BPA also operate dedicated fiber optic lines that are attached to the existing transmission line pole structures. In general, vegetation management requirements of pipelines are more restrictive than the vegetation management requirements for the transmission line described herein. For example, trees and shrubs are expected to be mowed or removed on a more regular basis than for the transmission lines to prevent damage to the pipeline by large roots. In addition, a corridor of herbaceous vegetation may be maintained both to keep the area free of large tree and shrub roots and to be able to easily, visually inspect the pipeline corridor from the ground and/or air. As noted above, the OPL traverses west to east within several easements north of the PSE and BPA substations at the southern end of the project area, and again is within the Project transmission line easement in the northern end of the Project area where the Renton City limits intersect with unincorporated King County. This, and other co-located utilities act as a regular, contributing source of ongoing vegetation maintenance in the shared corridor. Most of the study area corridor in Renton has been developed. Vegetation in residential, commercial, and industrial areas can be generally described as maintained yards or landscaped. On parcels that have not been developed as commercial or residential property, vegetated areas are often dominated by invasive plants including Himalayan blackberry and reed canarygrass. Forested patches are limited to topographically low regions near the Cedar River and Honey Dew Creek. 4.3 Critical Areas This section defines Renton-regulated critical areas per Section 4-3-050 (Critical Areas Regulations) of the RMC and describes the general location(s) of each critical area type in the proposed Project corridor. Regulated critical areas include wetlands, streams, habitat conservation areas, flood hazard areas, geologic hazard areas (i.e., steep slopes, landslide hazards, erosion hazards, seismic hazards, and coal mine hazards), and wellhead protection areas. Wetlands Renton defines wetlands as follows (RMC 4-11-230): PSE Energize Eastside Project Renton Critical Areas Report 14 Areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Wetlands do not include those artificial wetlands intentionally created from nonwetland sites, including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway. Wetlands include artificial wetlands created from nonwetland areas to mitigate the conversion of wetlands. Seven wetlands were identified in the vicinity of the proposed Project corridor in Renton. They are generally located near the Cedar River and south, between SE Cedar Ridge Drive and the Shadow Hawk neighborhood. Wetlands will not be directly impacted as a result of the Project (Section 7). See Section 5.1.1 for further description of identified wetlands and Appendix A for wetland locations. Streams and Lakes Renton defines streams and lakes by class in RMC 4-3-050(G)(7) as follows: Type S: Waters inventoried as “Shorelines of the State” under chapter 90.58 RCW. These waters are regulated under Renton’s Shoreline Master Program Regulations, RMC 4-3-090. Type F: Waters that are known to be used by fish or meet the physical criteria to be potentially used by fish and that have perennial (year-round) or seasonal flows. Type Np: Waters that do not contain fish or fish habitat and that have perennial (year-round) flows. Perennial stream waters do not go dry any time of a year of normal rainfall. However, for the purpose of water typing, Type Np waters include the intermittent dry portions of the perennial channel below the uppermost point of perennial flow. Type Ns: Waters that do not contain fish or fish habitat and have intermittent flows. These are seasonal, non-fish habitat streams in which surface flow is not present for at least some portion of a year of normal rainfall and are not located downstream from any stream reach that is a Type Np Water. Ns Waters must be physically connected by an above-ground channel system to Type S, F, or Np Waters. Under this section, non-regulated features include: …irrigation ditches, grass-lined swales and canals that do not meet the criteria for Type S, F, Np, or Ns Non-regulated waters may also include streams created as mitigation. Purposeful creation must be demonstrated through documentation, photographs, statements and/or other persuasive evidence. A total of four streams are located along the proposed Project corridor in Renton. Stream MR01 (Honey Dew Creek) is located on the north side of Renton, north of The Watershed Company January 2018 15 SR-900, and is a tributary to May Creek. The corridor crosses the Cedar River located further to the south, near the Maple Valley Highway. Streams NR01 (Ginger Creek) and NR02 are tributaries to the Cedar River, located between the Talbot Hill substation at the corridor’s southern extent and the Shadow Hawk neighborhood. No lakes are present in the Project area. See Section 5.1.1 for detail of stream types. Streams will not be directly impacted as a result of the Project (Section 7). Habitat Conservation Areas Renton provides two classifications or definitions related to regulated habitat areas that vary slightly. The following are a “classification of critical habitats” from RMC 4-3-050(G)(6) and definition of “critical habitat” from RMC 4-11-030, respectively: Classification of Critical Habitats: Habitats that have a primary association with the documented presence of non-salmonid or salmonid species (see subsection L1 of this Section and RMC 4-3-090, Shoreline Master Program Regulations, for salmonid species) species proposed or listed by the Federal government or State of Washington as endangered, threatened, sensitive and/or of local importance. Critical Habitat or Critical Wildlife Habitat: Habitat areas associated with threatened, endangered, sensitive, monitored, or priority species of plants or wildlife and which, if altered, could reduce the likelihood that the species would maintain and reproduce over the long term. Available Habitat The Project area is located in an urban and developed landscape. While the power line corridor is vegetated, vegetation predominantly consists of low- growing grasses, landscape plants and invasive plant species typical of maintained utility corridor areas. The corridor generally offers little in terms of habitat value when compared to other natural urban parks and greenspaces, which are expected to provide more vegetative cover, structure, and diversity, and fewer invasive plant species. Two forested patches are present in the Project area that are considered to have an increased potential for wildlife use (when compared to other Project areas in Renton); these include the forested ravines associated with Honey Dew Creek and the Cedar River. Even at these locations, original construction of transmission lines, existing and ongoing vegetation maintenance activities associated with the corridor, and the surrounding urban landscape setting reduce the likelihood that regulated species will utilize power line corridor areas for breeding. WDFW’s online mapping program, Priority Habitat and Species (PHS) on the Web, was reviewed for known priority habitats in the Project area. Two Biodiversity Areas and Corridors are mapped on forested slopes north and south PSE Energize Eastside Project Renton Critical Areas Report 16 of the Cedar River, respectively. North of this area, two small freshwater pond polygons are also shown. The areas located at and in the vicinity of the freshwater pond polygons were screened during the original delineation study; no ponds or wetlands are located in the vicinity of these mapped features. The environmental designation of the shoreline zone on the south side of the Cedar River is Urban Conservancy, qualifying this area as a Class 1 Fish and Habitat Conservation Area per RMC 4-3-090.D.2.c.iii. Federally-listed Species Endangered Species Act (ESA) documentation for the south segment of the Project, which includes the South Bellevue Segment, Newcastle, and Renton, addresses federally-listed species. As summarized in that document, the proposed Project will have no effect on ESA-listed species based upon lack of documented use, lack of suitable habitat, and/or avoidance of in-water work. State-listed Species State-listed species, that are not also listed as federally threatened or endangered (i.e., covered in the ESA document) are provided in Table 2. Of the species listed in Table 2, none are expected to occur in the Project area; use of the corridor is precluded by absence of suitable habitat and/or the species’ known distribution and range in Washington State. Table 2. State-listed wildlife species, excluding those listed as federally endangered and threatened. Wildlife Type Common Name Scientific Name Listing Status1 State Federal Mammals fisher Martes pennanti SE FSC - Habitat/Distribution: Historic range includes western Washington lowlands. Current range is fragmented in Washington (and is from the species reintroduction in national parks) and more extensive in Canada. Preferred habitat is closed-canopy forests. - Determination: Distribution does not overlap Project area. gray whale Eschrichtius robustus SS -- - Habitat/Distribution: Marine. - Determination: Habitat not present in Project area. Mazama pocket gopher Thomomys mazama ST FSC2 - Habitat/Distribution: Distribution limited to prairie habitats in Pierce and Thurston Counties. - Determination: Distribution does not overlap Project area. sea otter Enhydra lutris SE FSC - Habitat/Distribution: Marine. The Watershed Company January 2018 17 Wildlife Type Common Name Scientific Name Listing Status1 State Federal - Determination: Habitat not present in Project area. Birds American white pelican Pelecanus erythrorhynchos ST -- - Habitat/Distribution: Breeding and non-breeding range is limited to central and eastern Washington. - Determination: Distribution does not overlap Project area. common loon Gavia immer SS -- - Habitat/Distribution: Known to breed on secluded lakes in King County. Commonly over winters in protected marine waters of Puget Sound. - Determination: Habitat not present in Project area. ferruginous hawk Buteo regalis ST -- - Habitat/Distribution: Steppe or shrub-steppe habitat of eastern Washington Counties. - Determination: Habitat and distribution does not overlap Project area. greater sage-grouse Centrocercus urophasianus ST FSC - Habitat/Distribution: Shrub-steppe habitats of central and eastern Washington. - Determination: Habitat and distribution does not overlap Project area. sandhill crane Grus canadensis SE -- - Habitat/Distribution: No historic or current breeding sites in King County. - Determination: Distribution does not overlap Project area. Columbian sharp-tailed grouse Tympanuchus phasianellus ST -- - Habitat/Distribution: Historical range is non-forested areas east of Cascades; current range is much smaller and fragmented in eastern Washington. - Determination: Distribution does not overlap Project area. tufted puffin Fratercula cirrhata SE -- - Habitat/Distribution: Coastal waters of Washington. - Determination: Distribution does not overlap Project area. upland sandpiper Bartramia longicauda SE -- - Habitat/Distribution: Scattered historical breeding records for eastern Washington; may now be extirpated. - Determination: Distribution does not overlap Project area. Reptiles and Amphibians Western pond turtle Actinemys marmorata SE -- - Habitat/Distribution: Historical distribution likely included western King County; however, no current populations are known in this area. In Washington, the species was essentially extirpated by the 1980s. Important aquatic habitat features include underwater refugia, still/slow water, and basking structures. - Determination: Suitable aquatic habitat may be available in permanently PSE Energize Eastside Project Renton Critical Areas Report 18 Wildlife Type Common Name Scientific Name Listing Status1 State Federal ponded areas of Wetland NR02 and Wetland NR03. However, the local distribution and populations (only three known, none of which are in King County) of this species have been well studied and indicate that western pond turtles are not likely to occur in the Project area. Larch Mountain salamander Plethodon larselli SS -- - Habitat/Distribution: Populations generally limited to southern Washington counties near the Columbia River Gorge. - Determination: Distribution does not overlap Project area. Northern leopard frog Lithobates pipiens SE -- - Habitat/Distribution: Current and historic distribution limited to eastern Washington. - Determination: Distribution does not overlap Project area. Fishes pygmy whitefish Prosopium coulterii SS -- - Habitat/Distribution: Only known population in King County is in Chester Morse Lake and associated portions of the Cedar and Rex Rivers (tributaries for breeding); all populations in Washington are believed to have been identified. - Determination: Distribution does not overlap Project area. margined sculpin Cottus marginatus SS -- - Habitat/Distribution: Confined to the Tucannon and Walla Walla drainages in southeastern Washington. - Determination: Distribution does not overlap Project area. Olympic mudminnow Novumbra hubbsi SS -- - Habitat/Distribution: Known populations in southern and western lowlands of the Olympic Peninsula, the Chehalis and lower Deschutes River drainages, and south Puget Sound lowlands west of the Nisqually River. Recent occurrences in King and Snohomish Counties are considered to be outside of the species’ natural range. - Determination: Project area is located outside of species’ natural range. Insects Mardon skipper Polites mardon SE FSC - Habitat/Distribution: Distribution in Puget Prairie (Pierce and Thurston counties) and South Cascades (Klickitat and Yakima counties). - Determination: Distribution does not overlap Project area. 1 Listing Status Codes: SE = State Endangered SS = State Sensitive ST = State Threatened FSC = Federal Species of Concern 2 depending upon subspecies. The Watershed Company January 2018 19 Priority Species WDFW’s PHS data were also reviewed for the Project vicinity (PHS on the Web). Salmonid fish use is mapped for the Cedar River and Honey Dew Creek and as stated previously, Biodiversity Areas and Corridors are shown north and south of the Cedar River. According to WDFW’s online databases (PHS on the Web and SalmonScape), salmonid species known or modeled to occur in the Cedar River are cutthroat trout, bull trout, steelhead, kokanee, sockeye salmon, Chinook salmon, and coho salmon, thereby establishing the Cedar River as a Habitat Conservation Area (HCA). Similarly, salmonids known or modeled to occur in Honey Dew Creek include steelhead, Chinook salmon, coho salmon, sockeye salmon, and cutthroat trout, thereby establishing Honey Dew Creek as a HCA as well. In addition to reviewing WDFW’s database (PHS on the Web) for known PHS locations, the Priority Habitats and Species List (WDFW 2008) was reviewed in conjunction with species’ known distribution, range, and habitat, to determine the likelihood of priority species’ association with observed habitat in the Project area. A list of 95 priority species for King County (WDFW 2013) were reviewed for this assessment. The vast majority are not expected in the Project area, using the same process outlined in Table 2, due to a lack of suitable habitat types or special habitat features. Priority species that have the greatest potential to utilize habitat in the corridor are Columbian black-tailed deer, western toad, great blue heron, pileated woodpecker, and cavity nesting ducks. These species can be relatively common in urban settings, and are discussed below. Columbian black-tailed deer (Odocoileus hemionus columbianus) are Washington’s most common deer sub-species. They are relatively tolerant of disturbance and occur in a variety of habitats from residential areas and logged lands to coniferous forests. Their priority-species status is based upon recreational, commercial, and/or tribal importance (WDFW 2008). Local populations and habitat areas are not considered to be in jeopardy. Columbian black-tailed deer are not dependent upon habitat in the Project corridor. Furthermore, habitat in the corridor is not expected to be significantly altered by the proposed transmission line upgrade. Columbian black-tailed deer use of the corridor is expected post-Project construction. Temporary construction activities have the potential to affect the distribution of some individuals. Deer are expected to avoid construction activities by moving to other habitat areas. There are no areas in the corridor that are considered a HCA based upon association with Columbian black-tailed deer at this time. PSE Energize Eastside Project Renton Critical Areas Report 20 Western toad (Anaxyrus boreas) range spans much of Washington State including western Washington and the greater Seattle area. The species reportedly remains common throughout much of its range but has experienced population declines. Western toad can be found in many habitats including desert springs and streams, meadows, woodland, mountain wetlands, and agricultural land (IUCN SSC Amphibian Specialist Group 2015). Western toad habitat in the study area is generally limited to aquatic and terrestrial habitats associated with the Cedar River including Wetlands NR02 and NR03 that could be used for breeding (i.e., shallow slow-moving water). PHS on the Web (WDFW n.d.) documents western toad occurrences in King County, but none are in the vicinity of the Project area. No western toads were observed during field work activities. Project activities will not significantly impair the habitat in the Cedar River ravine, where western toad habitat is most suitable. Rather, wetland and buffer enhancement is proposed in the Cedar River area which could improve habitat conditions. There are no areas in the corridor that are considered a HCA based upon association with western toad at this time. Great blue herons (Ardea Herodias) are large wading birds most often found near water. Great blue herons forage in a variety of habitats near streams, lakes, ponds, wetlands, saltwater shorelines, and upland fields. They nest in colonies, typically in trees near foraging habitat. There are no known great blue heron nest sites (i.e., rookeries) in close proximity to the Project area (WDFW n.d.). One great blue heron was detected near the Cedar River and Wetland NR02 during October 2017 field work activities. The Cedar River and Wetland NR02 likely provide foraging habitat for this species. If an active heron rookery is identified along the Project corridor, a PSE avian biologist will develop and implement a strategy to prevent impacts to the heron rookery during the nesting season in coordination with WDFW. Project activities will not significantly alter the habitat in the Cedar River ravine. There are no areas in the corridor that are considered a HCA based upon association with great blue heron at this time. Pileated woodpeckers (Dryocopus pileatus) most often nest in old-growth forest and mature forest stands. However, they are increasingly found in urban areas as long as there are large trees that can provide roosting and nesting habitat. One pileated woodpecker was observed in the Honey Dew Creek ravine during field work activities in 2015. The topographic relief between the transmission lines and existing vegetation in the Honey Dew Creek and Cedar River ravines has allowed for forests to become established beneath the transmission lines at these locations. Outside of these ravines, the Project area does not contain the appropriate vegetation The Watershed Company January 2018 21 to support this species due to the vegetation management requirements associated with the power lines; however, pileated woodpeckers have been known to use utility poles for nesting. Pileated woodpeckers may utilize the forested habitat of the Honey Dew Creek and Cedar River ravines, as well as utility poles in the Project area, for some portion of their life history. If pileated woodpeckers are observed excavating poles, trees, or snags within the Project area, PSE avian biologists will be consulted to determine whether the pole, tree, or snag is being used for nesting or foraging. If it is determined to be in use for foraging by pileated woodpeckers, the Project will have minimal effects by potentially causing temporary disturbance to foraging behavior. If pileated woodpecker nests are found, depending on nest occupancy, a PSE avian biologist will develop and implement a strategy to prevent impacts to the pileated woodpeckers during the nesting season in coordination with WDFW during construction and maintenance activities. There are no areas in the corridor that are considered a HCA based upon association with pileated woodpecker at this time. Even so, recommended mitigation strategies and BMPs currently proposed include the creation of habitat snags, retaining stumps, and placement of large woody debris, consistent with WDFW’s general management recommendations for this species (Lewis and Azerrad 2003). Cavity nesting duck habitat consists of wetlands, riparian areas, lakes, or beaver ponds that contain a forested canopy with abundant downed logs and downed woody debris. Suitable cavity nesting duck habitat, namely for hooded mergansers and wood ducks in western Washington, exists in the study area in the vicinity of Wetlands NR02 and NR03 near the Cedar River. Project impacts will occur entirely outside of the jurisdictional shoreline and will not negatively alter the habitat in the Cedar River ravine; new transmission lines will span the ravine and construction activities will not occur at the bottom of the ravine. Proposed mitigation includes restoration of a portion of Wetland NRO2 which will improve habitat conditions. While no cavity nesting ducks are known to be present in the Project area currently, if they are present, they could be disturbed by increased noise but would be expected to continue use of the area after construction work is complete. There are no areas in the corridor that are considered a HCA based upon association with cavity nesting ducks at this time. Other priority species that are less likely to use habitat available in the Project corridor, but may be present particularly while traveling or foraging include PSE Energize Eastside Project Renton Critical Areas Report 22 Townsend’s big-eared bat (Corynorhinus townsendii), Vaux’s swift (Chaetura vauxi), and band-tailed pigeon (Patagioenas fasciata). However, these species are not closely associated with habitat found in the existing transmission line corridor. Any disturbance from Project-related activities would be temporary and would not impede the foraging of nearby habitats. Species of Local Importance Renton does not currently maintain or regulate a list of species of local importance. HCA Summary To summarize, the south side of the Cedar River within shoreline jurisdiction is considered a Class 1 Fish Habitat Conservation Area; and the Cedar River and Honey Dew Creek are considered Habitat Conservation Areas. The associated stream buffers and critical area regulations for streams are expected to adequately protect the Cedar River and Honey Dew Creek habitat areas for the duration of the Project. Furthermore, no impacts are proposed to the Cedar River ravine within shoreline jurisdiction. While Columbian black-tailed deer, western toad, pileated woodpecker, and cavity nesting ducks could be expected to utilize habitat in the Project corridor, they are not closely associated with the available habitat and proposed activities are not expected to significantly affect the use of the corridor by these species. At this time no additional HCAs are considered to be present in the Project area. In addition, PSE implements an Avian Protection Plan to protect avian wildlife from harmful interactions with their utility equipment. The Plan includes preventing the creation of potentially harmful nests and monitoring known nest sites when construction activities occur in close proximity during the nesting season (Puget Sound Energy n.d.). Potential Project impacts to birds that could be expected to utilize habitat in the Project area are mitigated through the PSE’s bird protection programs and procedures. Flood Hazard Areas The City of Renton defines Flood Hazard Areas in RMC 4-3-050(G)(4) as follows: Flood hazard areas are defined as the land in the floodplain subject to one percent (1%) or greater chance of flooding in any given year. Designation on flood maps always includes the letters A or V. Flood hazard areas are mapped along the Cedar River in the corridor. Flood hazard areas include both the 100-year floodplain and floodway. As Project activities are not proposed within flood hazard areas, impacts will not occur. The Watershed Company January 2018 23 Geologic Hazard Areas Geologic hazard areas are regulated as critical areas per RMC 4-3-050(G)(5). Geologically hazardous areas include steep slopes, landslide hazards, erosion hazard, seismic hazards, and coal mine hazards as defined below. a. Steep Slope Types: i. Sensitive Slopes: A hillside, or portion thereof, characterized by: (a) an average slope of twenty five percent (25%) to less than forty percent (40%) as identified in the City of Renton Steep Slope Atlas or in a method approved by the City; or (b) an average slope of forty percent (40%) or greater with a vertical rise of less than fifteen feet (15') as identified in the City of Renton Steep Slope Atlas or in a method approved by the City; (c) abutting an average slope of twenty five percent (25%) to forty percent (40%) as identified in the City of Renton Steep Slope Atlas or in a method approved by the City. This definition excludes engineered retaining walls. ii. Protected Slopes: A hillside, or portion thereof, characterized by an average slope of forty percent (40%) or greater grade and having a minimum vertical rise of fifteen feet (15') as identified in the City of Renton Steep Slope Atlas or in a method approved by the City. b. Landslide Hazards: i. Low Landslide Hazard (LL): Areas with slopes less than fifteen percent (15%). ii. Medium Landslide Hazard (LM): Areas with slopes between fifteen percent (15%) and forty percent (40%) and underlain by soils that consist largely of sand, gravel or glacial till. iii. High Landslide Hazards (LH): Areas with slopes greater than forty percent (40%), and areas with slopes between fifteen percent (15%) and forty percent (40%) and underlain by soils consisting largely of silt and clay. iv. Very High Landslide Hazards (LV): Areas of known mapped or identified landslide deposits. c. Erosion Hazards: i. Low Erosion Hazard (EL): Areas with soils characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having slight or moderate erosion potential, and a slope less than fifteen percent (15%). ii. High Erosion Hazard (EH): Areas with soils characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having severe or very severe erosion potential, and a slope more than fifteen percent (15%). d. Seismic Hazards: PSE Energize Eastside Project Renton Critical Areas Report 24 i. Low Seismic Hazard (SL): Areas underlain by dense soils or bedrock. These soils generally have site classifications of A through D, as defined in the International Building Code, 2012. ii. High Seismic Hazard (SH): Areas underlain by soft or loose, saturated soils. These soils generally have site classifications E or F, as defined in the International Building Code, 2012. e. Coal Mine Hazards: i. Low Coal Mine Hazards (CL): Areas with no known mine workings and no predicted subsidence. While no mines are known in these areas, undocumented mining is known to have occurred. ii. Medium Coal Mine Hazards (CM): Areas where mine workings are deeper than two hundred feet (200') for steeply dipping seams, or deeper than fifteen (15) times the thickness of the seam or workings for gently dipping seams. These areas may be affected by subsidence. iii. High Coal Mine Hazard (CH): Areas with abandoned and improperly sealed mine openings and areas underlain by mine workings shallower than two hundred feet (200') in depth for steeply dipping seams, or shallower than fifteen (15) times the thickness of the seam or workings for gently dipping seams. These areas may be affected by collapse or other subsidence. All geologic hazard area types are present in the study area. They have been reviewed and summarized in a report by GeoEngineers (Appendix E), the findings of which have been incorporated into this report where appropriate. According to GeoEngineers, mapped sensitive and protected steep slopes and moderate or unclassified landslide hazard areas are present within the Project area, however many of these areas are developed and include rockeries, landscaped residential or commercial development slopes and cut slopes associated with paved roadways. GeoEngineers states that the following areas (described in terms of proposed activity) are unlikely to be adversely impacted by the Project and are excluded from their detailed analysis: One tree removed in the mapped corridor east of North 23rd Court; Multiple trees removed east of the residence at 2101 Newport Court NE; One tree removed east of the residence at 23118 NE 18th Street; One tree removed on the east side of the Goodwill parking lot at 3208 NE Sunset Boulevard; Multiple trees removed on the east side of an existing parking lot for 3244 NE 12th Street; Multiple trees removed on the east side of existing residence from 1082 to 1074 Lynwood Avenue NE; The Watershed Company January 2018 25 One tree removed on the campus of the Renton Technical College; and One tree removed west of the apartment complex at SE 8th Street and Harrington Place SE. Localized natural areas of sensitive and protected steep slopes and moderate or unclassified landslide hazard areas in the Project area include the Honey Dew Creek drainage and the Cedar River drainage, which include slopes greater than 40 percent with a 15-foot vertical elevation rise. GeoEngineers focused their analysis on these areas. For the purposes of the impact analysis, these areas are referred to as priority steep slope and priority landslides hazard areas and are shown in the attached critical area maps (Appendix A). A detailed discussion of proposed Project impacts to geologic hazard areas is provided in Section 7 of this report. Erosion hazards are located on slopes north and south of the Cedar River and Honey Dew Creek. The only mapped seismic hazard area in the study area is associated with the Cedar River and lands immediately adjacent to the river. Coal mine hazards are mapped from the southern end of the study area, including the Talbot Hill Substation, to the Shadow Hawk neighborhood. Wellhead Protection Areas Renton defines Wellhead Protection Areas in RMC 4-3-050(A)(8) as follows: …the portion of an aquifer within the zone of capture and recharge area for a well or well field owned or operated by the City. The following Wellhead Protection Area Zones may be designated: (a) Zone 1: The land area situated between a well or well field owned by the City and the three hundred sixty five (365) day groundwater travel time contour. (b) Zone 1 Modified: The same land area described for Zone 1 but for the purpose of protecting a high-priority well, wellfield, or spring withdrawing from a confined aquifer with partial leakage in the overlying or underlying confining layers. Uses, activities, and facilities located in this area are regulated as if located within Zone 1 except as provided by this subsection G8. (c) Zone 2: The land area situated between the three hundred sixty five (365) day groundwater travel time contour and the boundary of the zone of potential capture for a well or well field owned or operated by the City. If the aquifer supplying water to such a well, well field, or spring is naturally protected by confining overlying and underlying geologic layers, the City may choose not to PSE Energize Eastside Project Renton Critical Areas Report 26 subdivide a Wellhead Protection Area into two (2) zones. In such a case, the entire Wellhead Protection Area will be designated as Zone 2. The study area spans wellhead protection areas mapped as Zone 1 and Zone 2. Zone 1 encompasses the Cedar River. Zone 2 surrounds Zone 1, excludes the Talbot Hill Substation, and extends north. They have been reviewed and summarized in a report by GeoEngineers (Appendix E), the findings of which have been incorporated into this report where appropriate. As with their analysis of proposed actions within geologic hazard areas, GeoEngineers’ review focuses on the Honey Dew Creek and Cedar River drainage areas. Project actions are not expected to impact wellhead protection areas in these drainage areas. 4.4 Shorelines of the State The Cedar River is the only Shoreline of the State present in the Project area. Shorelines of the State and critical areas located in shoreline jurisdiction are regulated under RMC 4-3-090 (Shoreline Master Program [SMP] Regulations) and are defined as follows: The Renton Shoreline Master Program applies to Shorelines of the State, which include Shorelines of Statewide Significance and shorelines as defined in chapter 4-11 RMC and as listed below. 1. Shorelines of Statewide Significance: a. Lake Washington; b. Green River (the area within the OHWM of the Green River is not within the Renton City Limits, but portions of the two hundred foot (200') shoreline jurisdiction are within City limits). 2. Shorelines: a. Cedar River; b. May Creek from the intersection of May Creek and NE 31st Street in the southeast quarter of the southeast quarter of Section 32-24-5E WM; c. Black River; d. Springbrook Creek from the Black River on the north to SW 43rd Street on the south; e. Lake Desire (in the City’s potential annexation area at the time of adoption of the Shoreline Master Program). 3. The Jurisdictional Area Includes: a. Lands within two hundred feet (200'), as measured on a horizontal plane, from the OHWM, or lands within two hundred feet (200') from floodways, whichever is greater; b. Contiguous floodplain areas; and The Watershed Company January 2018 27 c. All marshes, bogs, swamps, and river deltas associated with streams, lakes, and tidal waters that are subject to the provisions of the State Shoreline Management Act. A combination of field data and GIS inventories were used to map Cedar River shoreline jurisdiction. Floodway and floodplain areas were provided by City of Renton GIS. Within the Project area, no floodplain extends outside of the mapped floodway. The mapped floodway overlaps with the delineated ordinary high water mark (OHWM) on the north bank of the river and extends slightly beyond it on the south bank. As a result, a buffer of 200 feet was applied to the Cedar River floodway to form the basis for shoreline jurisdiction. On the south bank of the river, a delineated wetland (Wetland NRO2) falls within that 200-foot buffer and extends outside of the 200-foot buffer to the south. Consistent with the Shoreline Management Act and RMC, this wetland was considered “associated” with the Cedar River, and the shoreline jurisdiction was extended to encompass its entire delineated boundary. On the north bank of the Cedar River a potential wetland, “Cedar North”, was also identified within 200 feet of the OHWM on the northern bank of the Cedar River, which likely extends outside of the 200-foot buffer to the north. However, this feature was not delineated. Therefore, the extent of shoreline jurisdiction on the north side of the Cedar River is approximated, conservatively to encompass the approximated area of this wetland. The Project has been designed to avoid all impacts within shoreline jurisdiction. Conservatively, this includes avoiding all tree removal and impacts to other native vegetation within the vicinity of Wetland NRO2 as well as the approximated boundaries of the Cedar North wetland which defines the northern extent of the shoreline jurisdiction boundary. Renton and the Department of Ecology have documented that the project should be reviewed as a maintenance and repair shoreline exemption (email communication between J. Ding and S. Leverette 11.6.17). 5 REGULATIONS 5.1 Local Regulations As noted above, most critical areas, including those within shoreline jurisdiction, are regulated under Section 4-3-050 (Critical Areas Regulations) of the RMC. Class 1 Fish and Wildlife Habitat Conservation Areas and wetlands within shoreline jurisdiction are regulated under the Renton SMP. PSE Energize Eastside Project Renton Critical Areas Report 28 Wetlands and Streams A summary of relevant wetland and stream critical area classifications and standard buffer widths provided in the Delineation Report (The Watershed Company 2016a) and 2017 additional delineation documentation (The Watershed Company 2017) in Appendices B and C are presented again in Tables 3 and 4, below. Standard buffer widths for wetlands outside of shoreline jurisdiction are based upon the type of land use proposed, wetland category (using the 2014 Ecology rating system), and habitat score. The proposed land use is not considered low impact due to the vegetation management requirements of the new lines. For wetlands within shoreline jurisdiction, the wetland category is based on the 2004 Ecology rating system (RMC 4-3-090.D.2.d.ii) and the minimum buffer width is based on the category and wildlife function score (RMC 4-3-090.D.2.d.iv). Standard buffer widths for streams are based upon the stream type. Table 3. Summary of wetland critical area classifications and standard buffer widths. Wetland Name 2014 Ecology Wetland Rating Category Standard Buffer Width (feet) Water Quality Hydrologic Function Habitat Total NR01 5 6 7 18 III 100 NR03 6 5 7 18 III 100 NR04 5 5 6 16 III 100 NR05 5 6 7 18 III 100 Talbot wetland* -- -- -- -- ~III ~100 2004 Ecology Wetland Rating (shoreline wetlands) NR02 12 12 29 53 II 225 Cedar north* -- -- -- -- ~III ~125 * Wetland not delineated or formally rated; rating is estimated and a moderate habitat score is presumed to determine approximate buffer width. The Watershed Company January 2018 29 Table 4. Summary of stream critical area classifications and standard buffer widths. Stream Name Stream Type Standard Buffer Width (feet) MR01 – Honey Dew Creek Type F 115 NR01 – Ginger Creek Type Np 75 NR02 Type Ns 50 Cedar River Shoreline 100 Functioning buffers are shown in Appendix A. Functioning buffers are generally characterized as vegetated upland areas adjacent to wetland and stream critical areas. Impervious surfaces and development have been removed from standard buffers to generate functioning buffers so as not to quantify existing impacts as new Project impacts. Data used to map impervious surfaces and development include the King County Impervious and Impacted Surface data (King County 2009), supplemented with land survey data and high-resolution aerial photography provided by PSE. Functioning buffers are the basis for the critical areas impact analysis in order to determine project impacts and mitigation needs. Additionally, RMC requires modification of the standard buffer width for wetlands and streams in certain circumstances. Buffers had been modified according to the following provisions: Per RMC 4-3-090 D.2.d.iv.a, buffers for wetlands in shoreline jurisdiction, … shall not include areas that are functionally and effectively disconnected from the wetland by a permanent road or other substantially developed surface of sufficient width and with use characteristics such that buffer functions are not provided and that cannot be feasibly removed, relocated or restored to provide buffer functions. Similarly, per RMC 4-3-050.G.2 footnote 6, for buffers for wetlands outside of shoreline jurisdiction: Areas that are functionally and effectively disconnected from the wetland by a permanent road or other substantially developed surface or sufficient width and with use characteristics such that buffer functions are not provided shall not be counted toward the minimum buffer unless these areas can be feasibly removed, relocated or restored to provide buffer functions. Therefore, portions of wetland buffers that are effectively disconnected from the wetland by a road or other permanent development have been removed. PSE Energize Eastside Project Renton Critical Areas Report 30 Per RMC 4-3-090 D.2.d.iv.e, the presence of steep slopes adjacent to wetlands in shoreline jurisdiction also alters the required buffer width as follows: Increased Buffer for Steep Slopes: Where lands within the wetland buffer have an average continuous slope of twenty percent (20%) to thirty five percent (35%), and the required buffer width is less than one hundred feet (100'), the buffer shall extend to a thirty percent (30%) greater dimension. In all cases, where slopes within the buffers exceed thirty five percent (35%), the buffer shall extend twenty five feet (25') beyond the top of the bank of the sloping area or to the end of the buffer associated with a geological hazard if one is present, whichever is greater. Wetlands NR02 and Cedar North are both adjacent to steep slopes, therefore their buffers have been extended in compliance with this provision. Finally, per 4-3-050.G.2, footnote 5- when a required stream/lake buffer falls within a protected slope or very high landslide hazard area, the stream/lake buffer width shall extend to the boundary of the protected slope of very high landslide hazard area. Stream MRO1 (Honey Dew Creek), Stream NRO1 (Ginger Creek), and Stream NRO2 have had their buffers extended to the top of adjacent slopes in compliance with this provision. The altered, functioning wetland and stream buffers described above have been used as the basis for the critical areas impact analysis and are shown on the maps in Appendix A. Geologic Hazard Areas Geologic hazard areas include steep slopes, landslide hazards, erosion hazards, seismic hazards, and coal mine hazards. Required buffers for these critical areas (or lack thereof) is indicated in Table 3, per RMC 4-3-050(G)(2). Per City requirements, these areas have been evaluated by GeoEngineers (Appendix E). The Watershed Company January 2018 31 Table 5. Summary of geologic hazard area buffer requirements. Geologic Hazard Area Buffer Requirements Steep Slopes - Sensitive Slopes - Protected Slopes Based upon the results of a geotechnical report and/or independent review, conditions of approval for developments may include buffers and/or setbacks from buffers. Landslide Hazards - Low - Medium - High - Very High Based upon the results of a geotechnical report and/or independent review, conditions of approval for developments may include buffers and/or setbacks from buffers. Very high landslide hazards require a 50-foot buffer. Erosion Hazards - Low - High None Seismic Hazards - Low - High None Coal Mine Hazards - Low - Medium - High Based upon the results of a geotechnical report and/or independent review, conditions of approval for developments may include buffers and/or setbacks from buffers. Per GeoEngineers, the Project area does not include any mapped very high landslide hazard areas and, as such, there are no required buffers in the project area. GeoEngineers does not recommend any additional buffer areas (Appendix E). Flood Hazard Areas Vegetation removal in the floodplain requires documentation that describes proposed impacts on the floodplain and instream habitat functions and processes and how the project will ensure there will be no adverse effect on listed salmonids in accordance with FEMA requirements. In compliance with federal ESA requirements, an endangered species act evaluation has been prepared for the Project which includes a discussion of Project wide floodplain impacts. No floodplain impacts will occur within Renton. Habitat Conservation Areas Renton has the option to establish buffer areas for activities in, or adjacent to, habitat conservation areas when needed to protect fish and wildlife habitats of importance. Buffers shall consist of an undisturbed area of native vegetation, or areas identified for restoration, established to protect the integrity, functions and values of the affected habitat. Per RMC 4-3-050.G.6.c, buffer widths shall be based on: PSE Energize Eastside Project Renton Critical Areas Report 32 1. Type and intensity of human activity proposed to be conducted on the site and adjacent sites. 2. Recommendations contained within a habitat assessment report. 3. Management recommendations issued by the Washington Department of Fish and Wildlife. As noted in Section 4.3.3, the Cedar River and Honey Dew Creek areas are considered Habitat Conservation Areas. This report documents available habitat within those areas, potential impacts and proposed mitigation for Project actions in compliance RMC 4-3-050.G.6.c. The associated stream buffers and critical area regulations for streams are expected to adequately protect the Cedar River and Honey Dew Creek habitat areas for the duration of the Project. No additional buffer requirements are recommended. Additionally, in compliance with federal ESA requirements, an endangered species act evaluation has been prepared for the Project. As summarized in that document, there will be no effect on ESA-listed species based upon lack of documented use, lack of suitable habitat, and/or avoidance of in-water work and vegetation removal where listed species are known to occur. In the South Bellevue Segment Project area, no federally-listed species are known to occur or have designated critical habitat. Wellhead Protection Areas No buffer is required for wellhead protection areas (RMC 4-3-050.G.2). 5.2 Alteration of Critical Areas and Buffers In general, Renton will not allow critical areas to be filled, graded, or altered. The RMC requires that an applicant adjust proposed site plans to avoid and/or minimize impacts to critical areas and their respective buffers. No proposal shall result in a loss of critical area functions or values (RMC 4-3-050.G.1). RMC 4-3-050.C.3 describes exemptions which may be applicable to utility projects. However, not all exemptions are applicable to activities in all critical area types. Specifically, none of the exemptions apply to actions within wellhead protection areas which are present throughout most of the Project area. Wetland and Stream Buffers If the proposed activity does not qualify as an exemption or exception in the Code, the City may impose or allow modifications to standard buffer widths of wetland and stream critical areas under certain circumstances. Alternate buffer widths may be approved by Renton if a detailed wetland study is submitted with clear rationale for why the standard buffer widths are The Watershed Company January 2018 33 unnecessary and how the alternate buffer widths satisfy criteria identified based on best available science (RMC 4-3-050-G.9.d.ii). There are also opportunities for buffer averaging and/or buffer reduction detailed in RMC 4-3-050-I.3. However, these are generally not appropriate mechanisms for a linear project such as this. Additionally, RMC 4-3-050.J.2.b- Criteria for Administrative Approval of Utilities in Stream/Lake or Buffer permits new utility lines and facilities to cross water bodies if certain criteria are met, which include that mitigation is provided per the requirements of RMC 4-3- 050.L. While the code does not appear to have a comparable provision to RMC 4-3- 050.J.2.b for utilities crossing wetlands, it permits wetland alterations if no net loss of function and acreage is achieved and mitigation is provided. In general, alterations to critical areas or buffers must provide mitigation to ensure that they do not result in a loss of critical area functions or values. Mitigation must be based on consideration of the best available science. For stream mitigation specifically, the City’s preference is to mitigate onsite followed by mitigation implementation in the same drainage sub-basin (RMC 4-3- 050.L.1.g.i). However, these mitigation provisions generally apply to alterations that result in a developed condition (fill), and loss of critical area/buffer area. As described in Section 7 below, wetland and stream buffer impacts for the Project are limited to vegetation removal/conversion. No permanent impacts resulting in conversion to a developed condition are proposed. Interagency guidance for mitigating vegetation conversion impact (in wetlands, specifically) is as follows (Ecology et al. 2006): Loss of functions due to the permanent conversion of wetlands from one type to another also requires compensation. For example, when a forested wetland is permanently converted to an emergent or shrub wetland (e.g., for a utility right- of-way) some functions are permanently lost or reduced. The ratios for conversion of wetlands from one type to another will vary based on the type and degree of the alteration, but they are generally one-half of the typical ratios for permanent impacts. Where functioning wetland or stream buffers are impacted by a conversion of vegetation (not fill or grading), the proposed minimum mitigation ratio to off-set impacts is 0.5:1, consistent with the guidance for this type of impact to wetland areas. Temporary wetland and stream buffer impacts are typically required to be restored in-place at a 1:1 ratio. PSE Energize Eastside Project Renton Critical Areas Report 34 Geologic Hazard Areas and Associated Buffers Proposed alterations to erosion hazard areas, landslide hazard areas, steep slope hazard areas, and associated buffers have been evaluated by GeoEngineers; findings are incorporated in this report and included as Appendix E. Project compliance with applicable geologic hazard area code sections is also provided in Appendix E and summarize in Section 9 of this document. 6 MITIGATION SEQUENCING Pursuant to RMC 4-3-050. L.1.b, PSE seeks to avoid and minimize impacts to the critical areas and associated buffers located in the Project corridor have been taken. Avoidance Proposed new poles have been sited to avoid any direct impacts to wetlands or streams. All impacts have been avoided within the shoreline jurisdiction including within all flood hazard areas. Completely avoiding pole impacts to geologic hazard areas and wellhead protection areas is not feasible due to the prevalence of those features in the Project area. Furthermore, pole replacement activities associated with the transmission line upgrade must occur in specific locations for proper functioning of the electrical system due to complex engineering considerations making pole placement in some critical areas unavoidable. Where avoidance wasn’t possible, PSE worked with engineers to minimize impacts through design revisions; such changes reduced pole footprints and increased line heights to avoid critical area impacts to the extent feasible. Temporary impact areas associated with construction access, pole construction work areas, and stringing sites also avoid critical areas to the extent feasible. For example, specific pole construction work areas have been adjusted to exclude critical areas on a pole-by-pole basis. Minimization Minimization techniques were utilized during the design process in order to limit impacts to critical areas and their associated buffers. Minimization measures included the following: 1. Utilizing the existing transmission line corridor, which has experienced significant disturbance as a result of adjacent development and ongoing corridor maintenance. The Watershed Company January 2018 35 2. When working within a critical area, limiting the construction disturbance to the minimum feasible size around each pole and access point. 3. Installing 230 kV transmission lines between poles with minimal site disturbance. Where feasible given maximum distance allowed between poles, the poles will be located outside of critical areas. Transmission lines will span above critical areas, minimizing ground disturbance, vegetation removal, and loss of critical area function. 4. Where vegetation removal is required in critical areas, trees will be accessed by foot, stumps will be left in the ground, and debris will be chipped or dispersed as appropriate, preventing critical area disturbance by large heavy equipment. Compensation To off-set unavoidable critical area impacts associated with the Project, mitigation will occur in accordance with RMC 4-3-050.L. Mitigation is expected to include restoration of temporary impacts (including maintenance of slope stability) and wetland and wetland and stream buffer enhancement in order to achieve equivalent or greater critical area functions and values compared to existing conditions. Mitigation needs have been calculated based upon anticipated impacts. The mitigation plan for the Lower Cedar River sub-basin, Riverview Park Mitigation Plan, is included as Appendix F of this report. An additional mitigation plan for impacts within the May Creek Basin will also be provided (conceptual plan is included as Appendix G). The approach and plans are discussed in Section 8. 7 UNAVOIDABLE PROJECT IMPACTS Impact types resulting from the Project have been quantified based upon the long-term condition of the proposed work areas and existing land cover types in the corridor. Quantified impacts have been characterized as one of four types using this analysis and include permanent, conversion, temporary, and no change. A summary of the impact types based on proposed work and existing land cover is provided in Table 6. Permanent impacts are characterized as a change from a vegetated critical area to a transmission line pole. No permanent impacts are proposed in wetlands, streams or stream buffers, flood hazard areas, or seismic hazard areas. Permanent impacts to wetland buffers are limited to one new pole and three increased footprints from Lake Tradition Line replacement poles. The quantity of PSE Energize Eastside Project Renton Critical Areas Report 36 permanent impacts occurring in wetland buffers is used to determine mitigation needs based upon the City requirements outlined in Section 5.2. Impacts to geologic hazard areas (including erosion hazard areas, landslide hazard areas, steep slopes and coal mine hazard areas) and wellhead protection areas are addressed by GeoEngineers (Appendix E) and summarized in the following sub- sections. Impacts that result in vegetation conversion are caused by vegetation management activities resulting in a shift from forested to shrubby or herbaceous vegetation. These impacts will be limited to disturbance of vegetation; soils will remain intact. Vegetation conversion impacts require mitigation when they occur in wetland and/or stream buffers, but since the magnitude of impact is less than permanent impacts, a reduced mitigation ratio is proposed using interagency guidance (Ecology et al. 2006). Wetland and stream buffer impacts that result in a vegetation conversion will be mitigated at one-half the typical ratio (0.5:1), at a minimum, for permanent buffer impacts to vegetation discussed in Section 5.2. Quantified vegetation conversion impacts are also presented for geologic hazard areas. However, this measure of impact was not relied upon by geotechnical professionals when assessing Project impacts in respective critical areas. GeoEngineers based their analysis on a review of geologic maps and geologic hazard maps, digital imagery, site visits, and PSE site plans (which included trees to be removed but not canopy loss). Conversion impacts in geologic hazard areas are presented for consistency and also to provide the reader with a comprehensive understanding of Project impacts. Conversion impacts in geologic hazard areas do not directly correlate to mitigation requirements as they do for wetland and stream critical area buffers. Temporary impacts will occur in geologic hazard areas, wetland and stream buffers, and wellhead protection areas as part of the following activities: pole installation, maintenance, and removal; and construction access route re- establishment/use. These areas will be restored in-place after construction work is complete. Where no change is anticipated, due to the existing land cover type in the Project area, no mitigation is required. Impact results categorized as no change have not been reported. Permanent, conversion, and/or temporary Project impacts are proposed in erosion hazard areas, steep slope and landslide hazard areas, coal mine hazard areas, wellhead protection areas, habitat conservation areas, and buffers associated with wetlands and streams. In addition to quantifying impacts by area, impacts have been qualitatively assessed by a qualified professional for The Watershed Company January 2018 37 each critical area type to be impacted. The results of the quantitative and qualitative analyses are discussed in the following sub-sections. PSE Energize Eastside Project Renton Critical Areas Report 38 Table 6. Matrix used for determining impact types based upon long-term condition of proposed activities and existing land cover types in critical areas and associated buffers. Existing Land Cover Types Impact Description Long-Term Condition1 Forested to be Removed Forested to Remain Understory only Other (mostly lawn) with understory no understory with understory no understory Proposed Activities Pole footprint (actual footprint of pole structure based on engineering drawings from PSE) Developed P P P P P P Pole buffer (6 foot radius outside of pole footprint) Mixed vegetation2 C C T T T T Access routes (20 foot width based on alignments from PSE) Mixed vegetation2 C C T T T T Pole construction work area Mixed vegetation2 C C T T T T Wire Zone Mixed vegetation2 C C NC NC NC NC Managed ROW Mixed vegetation2 C C NC NC NC NC Legal ROW Mixed vegetation2 C C NC NC NC NC Type of Impact based on proposed activity, long term condition, and existing land cover type: P = Permanent, C = Conversion, T = Temporary, NC = No Change 1 Long term condition determined in coordination with PSE. 2 Subject to varying height restrictions described in Section 3.3.4. The Watershed Company January 2018 39 7.1 Critical Area Impacts Wetland and Stream Buffer Impacts Permanent impact is proposed to wetland buffer as a result of one new pole on the south side of the Cedar River in the outer buffer of Wetland NRO2, and three increased footprints from Lake Tradition Line replacement poles in the buffer of the Talbot Wetland. Two existing poles (totaling 12 SF) will be removed from the overlapping buffers of Wetlands NRO1 and NRO5 and replaced outside of their buffer area, resulting in the removal of 12 SF of fill within this functioning buffer area. Following pole removal the holes will be filled in with dirt and restored with grass seed (Table 7). Vegetation conversion impacts are also proposed to wetland and stream buffers in the Project corridor in Renton (Table 7). Temporary impacts for the establishment of access routes and pole installation and maintenance will also occur in the buffers of Wetland NR01, Wetland NRO2, Wetland NR05, and the Talbot Wetland (Table 7). A qualitative description of buffer impacts can be found in Section 7.2 (Functional Lift Analysis) followed by a description of the mitigation activities proposed to compensate for the impact. PSE Energize Eastside Project Renton Critical Areas Report 40 Table 7. Wetland and stream buffer impacts by wetland and/or stream feature and sub-basin. Stream/Wetland Impact Type Area1 of Net Impact (SF) Source of Impact Lower Cedar River Stream NRO1 (Ginger Creek) Buffer Permanent 0 None Conversion 4,962 Removal of vegetation Temporary 0 None Stream NRO2 Buffer Permanent 0 None Conversion 311 Removal of vegetation Temporary 0 None Wetland NR01 Buffer Permanent -6 Removal of existing pole Conversion 1,562 Removal of vegetation Temporary 8,152 Access route Wetland NRO2 Buffer Permanent 13 New pole Conversion 9,423 Removal of vegetation Temporary 2,371 Pole work area, access road Wetland NRO5 Buffer Permanent -6 Removal of existing pole Conversion 313 Removal of vegetation Temporary 9,813 Access route Talbot Wetland Permanent 67 Replacement poles2 Conversion 0 None Temporary 6,220 Pole buffer, pole work areas TOTAL1 Lower Cedar River sub-basin Permanent: 68 SF Conversion: 15,948 SF Temporary: 19,235 SF May Creek Stream MRO1 (Honey Creek) Permanent 0 None Conversion 2,838 Removal of vegetation Temporary 0 None TOTAL1 May Creek sub-basin Permanent: 0 Conversion: 2,838 SF Temporary: 0 1 Area column does not sum to total impact reported because where wetland/stream buffers overlap total impact has been adjusted down to count each impact area only once 2Three Lake Tradition Line poles are being replaced in the buffer of the Talbot Wetland. Replacement poles are in the same location as existing poles, but have a larger footprint. Only the net increase in development footprint is counted. The Watershed Company January 2018 41 Geologic Hazard Area Impacts and Associated Buffer Impacts Impacts to geologic hazard areas have been reviewed by GeoEngineers based on PSE’s proposed activities. As stated previously, the main areas of the corridor associated with geologic hazards are the Honey Dew Creek and Cedar River drainage areas where several overlapping geologic hazards are mapped. As such, GeoEngineers focused their review of impacts to this area. New poles will be installed in erosion hazard areas, landslide hazard areas, steep slope hazard areas and coal mine hazard areas. However, new poles are replacing existing poles which will be removed. Per GeoEngineers Report (Appendix E), for poles located in geologic hazard areas, old poles should be cut one to two feet below the ground surface, leaving the remaining portion of the pole below ground in place in order to minimize impacts. Table 8. Geologic hazard area impacts associated with pole replacement in Project area. Geologic Hazard Area or Associated Buffer Number of New Poles1 (and proposed size in SF) Erosion Hazard Area 10 (283 SF) Landslide Hazard Area 9 (239 SF) Priority Steep Slope Hazard Area 7 (123 SF) Seismic Hazard Area 0 Coal Mine Hazard Area 18 (478 SF) 1 Several poles are present and/or are proposed in overlapping geologic hazard areas. Poles in table are counted in each area they occur in. Area based on pole diameter ranging from 3 feet to 6 feet depending on the pole type. Vegetation management activities will also result in impacts to geologic hazard areas. Impacts quantified by canopy removal are presented in Table 9 below as vegetation conversion, and are caused by tree removal associated with the Project. Vegetation conversion quantities presented here were not utilized by GeoEngineers in their analysis of Project impacts to geologic hazard areas. GeoEngineers’ review of geologic hazard areas included a site visit to evaluate the hazard areas identified along the slopes of Honey Dew Creek and the Cedar River. They determined that PSE’s proposed work is consistent with the management activities of the existing power line right-of-way and is not anticipated to impact the mapped geologic hazard area within these drainage areas (provided no tracked or rubber-tired equipment is used to remove trees). Their report notes that proposed removal of trees in the Honey Dew Creek PSE Energize Eastside Project Renton Critical Areas Report 42 drainage is located upslope of any identified recently active slope failures and is not anticipated to exacerbate localized slope failures. Recommended mitigation strategies are discussed in Section 8 of this report. Refer to the GeoEngineers Report for additional details (Appendix E). Table 9. Vegetation conversion impacts to geologic hazard areas in the Project area. Geologic Hazard Area or Associated Buffer Vegetation Conversion (SF) Source of Impact Erosion Hazard Area 19,512 Legal ROW, managed ROW, wire zone, Priority Landslide Hazard Area 18,291 Legal ROW, pole work area, managed ROW, wire zone, access road, pole buffer Priority Steep Slope Hazard Area 25,133 Wire zone, legal ROW, managed ROW, pole work area, pole buffer Seismic Hazard Area 0 None Coal Mine Hazard Area 25,424 Legal ROW, managed ROW, wire zone, access road Wellhead Protection Area Impacts Wellhead protection areas are mapped within most of the Project corridor. Impacts to wellhead protection areas have been reviewed by GeoEngineers based on PSE’s proposed activities (Appendix E). Project actions within mapped wellhead protection areas are summarized in Table 10 below. Impact reported for pole footprints in Table 10 accounts for where new pole footprints overlap existing pole footprints (only new area of impact resulting from the new, bigger, pole is counted). Table 10. Actions within wellhead protection areas in the Project area. Wellhead Protection Area Area (SF) Source of Impact Zone 1 Permanent 791 Pole footprints Conversion 0 none Temporary 23,196 Pole work area, access road, pole buffer Zone 2 Permanent 706 Pole footprints Conversion 40,696 Wire zone, managed ROW, access road, legal ROW, pole work area, pole buffer Temporary 131,387 Pole work area, pole buffer, access road, 1permanent impact reported for pole footprints accounts for where new pole footprints overlap existing pole footprints. Only new area of impact resulting from the new, bigger, pole is counted. The Watershed Company January 2018 43 As with their analysis of proposed actions within geologic hazard areas, GeoEngineers’ review focused on the Honey Dew Creek and Cedar River drainage areas. They determined that PSE’s proposed work in wellhead protection areas is consistent with the management activities of the existing power line right-of-way and is not anticipated to impact the mapped wellhead protection areas within these drainage areas (provided no tracked or rubber-tired equipment is used to remove trees). Recommended mitigation strategies are discussed in Section 8 of this report. Refer to the GeoEngineers Report for additional details (Appendix E). Habitat Conservation Area Impacts Three existing poles, totaling approximately 18 SF, will be removed from the HCA mapped south of the Cedar River, outside of the extent of shoreline jurisdiction. These poles will be replaced with one new pole totaling 13 SF. Thus, there will be a net reduction in fill in this HCA. The new pole is located outside of the 100-foot Cedar River buffer, and the entirety of the shoreline jurisdiction, as well asoutside of all non-shoreline stream and wetland buffers. The pole is located just north of an existing road and parking area associated with the Shadow Hawk development. It is not expected to significantly impact habitat in the area. Additionally, mitigation activities proposed in the vicinity of the Cedar River are expected to further compensate for the new pole by increasing habitat function in the Cedar River ravine over the existing condition (See Section 8). 7.2 Functional Lift Analysis Wetland and stream functional buffers have been qualitatively assessed, in addition to the quantitative analysis presented above. For the purposes of this section, the pre-existing condition of the Project area is compared against the proposed post-Project condition to ensure that no net loss of critical area functions is achieved. With mitigation, a net increase in function within the Project area is expected post-implementation. In general, proposed wetland and stream buffer impacts are located in areas that are disturbed and dominated by invasive plants such as non-native blackberry. The majority of these impacts are classified as a vegetation conversion that involve removal of native and non-native trees from buffer areas. Buffer impacts are proposed in three main areas - Honey Dew Creek, the Cedar River ravine (outside of shoreline jurisdiction), and the Talbot substation to Shadow Hawk development portion of the corridor south of the Cedar River ravine. Except for Honey Dew Creek, all other wetland and streams identified in the study area are located in the Lower Cedar River sub-basin. Buffer conditions of these features can be generally described based on location. Table 11 summarizes impacts, PSE Energize Eastside Project Renton Critical Areas Report 44 existing conditions, and proposed conditions in the three proposed impact areas. The functional lift analysis describes how the mitigation plan will provide equivalent or greater critical area functions when compared to existing conditions overall. The Watershed Company January 2018 45 Table 11. Descriptions of general impact area conditions and proposed changes. Critical Area Existing and Proposed Conditions May Creek Sub-basin Honey Dew Creek Buffer Existing Conditions: Honey Dew Creek is the only wetland or stream critical area in the Project area located in the May Creek sub-basin. The Honey Dew Creek buffers are predominantly forested with native tree species and include steep, protected slope areas. The forest understory is degraded in places where invasive weeds are patchy and homeless encampments have removed understory vegetation and compacted soils. Proposed Conditions: Conversion from forested buffer area to shrub buffer area as a result of tree removal to accommodate new, higher voltage transmission lines - 2,838 SF of canopy will be lost, predominantly near the outer portion of the buffer on the north side of the creek. Impacts will be mitigated through invasive species removal and native vegetation planting in the Honey Dew Creek buffer. Lower Cedar River Sub-basin Talbot to Shadow Hawk Area Wetland and Stream Buffers (Wetlands NRO1, NRO5, Talbot Wetland, and Stream NRO1) Existing Conditions: The buffers of wetland and streams located south of the Cedar River ravine between the Talbot Hill substation and the Shadow Hawk neighborhood are degraded due to the existing use of the corridor. This area is in close proximity to residential development and is part of the managed corridor. Roads, parking lots, commercial development, and trails established from overgrown access routes are also present in this area. The Talbot Hill area is also utilized by an extensive number of co-located critical utilities which also have vegetation management requirements. The BPA easement parallels the Project area in this portion of the corridor. Vegetation in this area is dominated by small trees, shrubs, and grasses. Areas are currently mowed that are within the overlapping BPA easement. Invasive species present include but are not limited to Himalayan blackberry, Scotch broom, and reed canarygrass. Proposed Conditions: Conversion from forested buffer area to shrub buffer area to accommodate new, higher voltage transmission lines Temporary impacts associated with establishment of access routes and pole installation and maintenance Removal of two existing poles from buffer area, resulting in a net reduction of 12 SF of buffer fill Installation of three replacement poles for the Lake Tradition Line in the same area as existing poles, but with a larger footprint resulting in 67 square feet of new developed area Corridor will continue to be maintained Impacts will be mitigated through enhancement of Wetland NRO2 and its buffer near the Cedar River. PSE Energize Eastside Project Renton Critical Areas Report 46 Critical Area Existing and Proposed Conditions Cedar River Ravine Wetland and Stream Buffers (Wetland NRO2, and Stream NRO2) Existing Conditions: The buffers of wetland and streams located in the Cedar River ravine contain a mix of native and nonnative vegetation; the canopy is dominated by native trees, while the understory contains native plants and dense patches of Himalayan blackberry and invasive knotweed. Proposed Conditions: One new pole in the outer buffer of Wetland NRO2, south of the Cedar River. Conversion from forested buffer area to shrub buffer area to accommodate new, higher voltage transmission lines Temporary impacts associated with establishment of access routes and pole installation and maintenance Impacts will be mitigated through restoration of Wetland NRO2 and adjacent buffer areas including: Removal of invasive vegetation Installation of native, transmission-line appropriate vegetation, including low-growing trees and shrubs. Snag dead trees in the overlapping wetland and stream buffer to remain as habitat features May Creek Sub-basin Honey Dew Creek As summarized in Table 11, 2,838 SF of vegetation conversion impact is proposed within the Honey Dew Creek buffer. This impact is predominately in the area of buffer which has been expanded to encompass the adjacent steep slopes, per code requirements (See Section 5.1.1). 18 trees total are proposed for removal. Trees proposed for removal are assumed to provide some water quality and hydrologic functions through interception of water (rainfall) and uptake of groundwater and nutrients. While these trees and their associated functions will be removed, the understory will be left in its existing condition with herbaceous or shrub vegetation, or will be restored through invasive species removal and installation of native shrub understory and transmission line appropriate trees. The water quality and hydrologic functions provided by potential replacement vegetation is expected to be comparable in water quality and hydrologic function to the existing small trees. Therefore, the net effect on water quality and hydrologic buffer functions anticipated from removing these three trees from respective buffer areas, is not expected to be significant. The Watershed Company January 2018 47 Removal of canopy is expected to reduce the structural and vegetative species diversity of the stream buffer areas as well as reduce forage opportunities for some urban wildlife species. However, the overall character and habitat functions of the buffer is not expected to change significantly as a result of the limited vegetation management proposed. Net Condition With the mitigation proposed, the vegetation conversion impacts to the Honey Dew Creek buffer are not expected to significantly change the water quality or hydrologic functions of the stream buffer area compared to existing conditions. A slight reduction in the variety of foraging habitat and vegetative structure for urban wildlife species is anticipated. However, the overall vegetation composition of the area is not expected to change substantially. Overall, the proposed mitigation is expected to improve critical area function through removal of invasive species and enhancement of the understory with native vegetation which will also help improve slope stability. Refer to Section 8 for additional discussion of the conceptual mitigation plan (Appendix G). Lower Cedar River Sub-basin Wetlands NRO1, NRO5, Talbot Wetland and Stream NRO1 Within the Talbot to Shadow Hawk area the majority of wetland and stream buffer impact is proposed in the buffer of Stream NRO1 (Ginger Creek) due to vegetation conversion resulting from the removal of eleven trees. As stated previously, trees proposed for removal are assumed to provide some water quality and hydrologic functions through interception of water (rainfall) and uptake of groundwater and nutrients. While these trees and their associated functions will be removed, the affected area will be left to become revegetated, likely with herbaceous or shrub vegetation. The water quality and hydrologic functions provided by potential replacement vegetation is expected to be comparable in water quality and hydrologic function to the existing small trees. Therefore, the net effect on water quality and hydrologic buffer functions anticipated from removing these trees from respective buffer areas, is not expected to be significant. Removal of canopy is expected to reduce the structural and vegetative species diversity of the stream buffer areas as well as reduce forage opportunities for some urban wildlife species. However, the overall character and habitat functions of the buffer (i.e., managed corridor dominated by non-native species) is not expected to change significantly as a result of the limited vegetation management proposed. Temporary impacts will incorporate standard BMPs and temporary erosion and sediment control (TESC) measures to minimize impacts to downstream water PSE Energize Eastside Project Renton Critical Areas Report 48 quality and hydrologic functions of the critical area buffer. Vegetation impacted in temporary work areas is expected to rebound within one growing season. Net Condition Vegetation conversion to these buffers is not expected to significantly change the water quality or hydrologic functions of the buffer areas compared to existing conditions. A slight reduction in the variety of foraging habitat and vegetative structure for urban wildlife species is anticipated. However, the overall vegetation composition of the area is not expected to change substantially due to the managed character of the corridor in this area. Mitigation for impacts to this area is proposed in the Cedar River area, within the same drainage basin, where restoration activities have the potential to provide the most value to overall critical area function in the Project corridor. Proposed mitigation will maintain overall critical area functions and values in the Lower Cedar River sub-basin. Refer to Section 8 for a discussion of the mitigation plan. Wetland NRO2, and Stream NRO2 All impacts to these wetland and stream buffers within the Cedar River ravine are located outside of shoreline jurisdiction, within the outer portion of the combined buffer area south of the Cedar River, and the very edge of the wetland buffer north of the Cedar River. As stated previously trees perform water quality and hydrologic functions through interception of rainfall and uptake of groundwater and nutrients. Native trees also provide important habitat functions. At this location in particular, trees are important to the Cedar River riparian area, provide cover and shade to associated wetland and stream areas and support a corridor along the Cedar River in which terrestrial and aquatic wildlife species may travel. Native trees are also expected to provide potential breeding and foraging habitat to some urban wildlife species. Tree removal, without mitigation could diminish the water quality, hydrologic, and habitat buffer functions at this location. Tree removal is not expected to significantly disturb understory vegetation and soils. Trees proposed for removal in these buffer areas are also within geologic hazard areas and will be accessed by foot and removed by hand-cutting with chainsaws per GeoEngineers recommendations. In addition, stumps will remain in the ground and tree debris scattered within the ROW. Non-native invasive plants (i.e., Himalayan blackberry and Scotch broom) dominant in nearby areas of the corridor have the potential to become established where vegetation removal is proposed. In order to mitigate for Project impacts and prevent further degradation of the wetland and stream buffers that could be expected to follow the removal of native trees, mitigation for all wetland and stream buffer impacts is proposed within the southern shoreline zone of the Cedar River ravine within Wetland The Watershed Company January 2018 49 NRO2 and adjacent buffer areas where the mitigation has the potential to provide the most benefit. Mitigation activities are expected to include the following: - removal of invasive plant species; - installation of a dense and diverse community of native, transmission- line appropriate plants including low-growing trees and shrubs; - creation of habitat snags using dead trees in the overlapping wetland and stream buffer The specific location and size of the mitigation area is presented in the Riverview Park Mitigation Plan (Appendix F), which has been designed to appropriately replace functions lost as a result of the one new pole and vegetation conversion in the Lower Cedar River sub-basin. Mitigation activities are expected to maintain or improve water quality, hydrologic, and habitat functions over existing conditions. Dense, native trees and shrubs are expected to compensate for the loss of water quality and hydrologic functions provided by larger trees. Habitat will be improved from existing conditions by removing invasive plant species, and installing a variety of native plants. Native plants will provide cover and forage opportunities for wildlife as well as aid in maintaining a wildlife travel corridor that crosses perpendicular to the transmission line corridor along the Cedar River ravine. Net Condition Mitigation activities are expected to maintain or improve water quality, hydrologic, and habitat functions of Wetland NRO2, and Stream NRO2 buffer areas over existing conditions. Dense, native trees and shrubs are expected to compensate for the loss of water quality and hydrologic functions provided by larger trees. Habitat will be improved from existing conditions by removing dense Himalayan blackberry, placing large woody debris, and installing a variety of native plants. Native plants will provide cover and forage opportunities for wildlife. By mitigating basin-wide wetland and stream buffer impacts at this location, shoreline function also benefits. Refer to Section 8 for a discussion of the mitigation plan. 7.3 Cumulative Impacts Impacts from past actions have shaped the Project vicinity since the mid-19th century, and continue to shape how Seattle and the Eastside are changing in response to development activities and trends. In general, landscape-scale and basin-level functions and processes are negatively impacted by increased impervious surface, critical area and buffer vegetation removal, and buffer area losses. This is common to urban areas like Renton which have experienced a PSE Energize Eastside Project Renton Critical Areas Report 50 general loss of upland forested, native meadow, riparian, and wetland habitat areas due to development. Urbanization tends to cause flashy stream hydrology, increased pollutant loads, sedimentation, and overall habitat loss, often resulting in few fragmented areas of high-value fish and wildlife habitat remaining in urban settings. Other large projects such as Sound Transit’s East Link Light Rail overlapping with the proposed Project can contribute to these ongoing trends and cumulative impacts on high-value uplands and wetlands in the vicinity. These changes, along with additional urban development, continue to incrementally reduce remaining habitat areas and aquatic resources. Although urbanization has resulted in an overall loss and degradation of available fish and wildlife habitat throughout the study area, current regulations and incentive programs have slowed the trend of habitat loss to a degree. In the case of fish passage, future permitted projects are likely to incrementally provide net benefit to habitat. Mitigation measures for these projects may include restoration or enhancement of degraded streams and wetlands and their associated buffers, thus providing water quality treatment for impervious surfaces that currently receive no treatment, removal of fish passage barriers, and planting of disturbed areas with native vegetation. These mitigation measures benefit fish and wildlife habitat when compared to existing conditions and improve conditions for federally listed threatened or endangered species, if present. In the short term, the Project will contribute to the incremental trend of degradation directly by removing trees and altering available habitat conditions, and indirectly by continuing to supply energy to support a growing, developing region. Mitigation is proposed to compensate for unavoidable Project impacts and replace associated functions and values in locations which will maximize benefit to multiple significant critical areas (shoreline associated wetlands, streams, steep slopes, riparian area of the Cedar River). Project mitigation will help to reduce cumulative impacts, but will not immediately replace all habitat lost. Replacing large significant trees with smaller planting-sized trees will not fully replace the habitat functions provided by the existing conditions. Including snags and large woody debris in mitigation plans will help to address the loss of forested habitat values in the short term, and over time the loss of function will be further addressed as mitigation areas mature. However, as stated above, with mitigation the Project is anticipated to cause a net improvement of critical area functions in the Project area. Project impacts will be appropriately mitigated in order to minimize the Project’s cumulative impacts critical areas. No long-term impacts to water resources are expected as a result of the Project. Mitigation measures to compensate for The Watershed Company January 2018 51 impacts identified in this report are proposed in the Riverview Park Mitigation Plan (Appendix F) and Honey Dew Creek Conceptual Mitigation Plan (Appendix G). 8 MITIGATION 8.1 Wetland and Stream Buffer Mitigation Approach As stated in Section 5, for alterations to wetland and stream buffers, Renton requires that compensatory mitigation be developed. Permanent buffer impacts must be mitigated on a 1:1 areal and functional basis. For vegetation conversion impacts, a reduced minimum mitigation ratio of 0.5:1 is proposed based on interagency guidance (Ecology et al. 2006). Renton prioritizes onsite mitigation followed by mitigation in the same drainage sub-basin (4-3-050.L). In order to determine a mitigation strategy and satisfy City preferences, locations for potential mitigation activities were first determined. Since the Project is long and linear in nature, it passes through and generates varying degrees of impact to three different wetland/stream buffer areas in Renton. The majority of impacts (85 percent) will occur in the Lower Cedar River sub-basin. As such, the Cedar River area was reviewed for mitigation potential. In the existing PSE easement, the southern shoreline of the Cedar River includes overlapping wetland and stream buffer areas and provides ample opportunity for restoration. The Cedar River site provides enough opportunity and area to mitigate for all wetland/stream buffer impacts that occur in the drainage basin. Ultimately Wetland NRO2 and adjacent buffer areas were determined to be the most appropriate location for mitigation as the wetland and buffer are inundated with invasive species. Restoration of a portion of the wetland, as well as some of its adjacent buffer, will provide a direct and significant increase in critical area function. As an alternative to the Cedar River area, the Talbot to Shadow Hawk area was also reviewed as a potential location for mitigation within the Lower Cedar River sub-basin. As described above, impacts are proposed to wetland and stream buffers in this area. However, the potential for mitigation to improve function in this area is limited by the ongoing maintenance requirements of the corridor which includes mowing within the BPA easement. When compared to the Cedar River mitigation site, this area was determined to be a lower priority for restoration. In general, mitigation sites are more successful when combined into fewer larger areas, rather than piecemealed across several smaller sites. Furthermore, the PSE Energize Eastside Project Renton Critical Areas Report 52 proposed Cedar River mitigation site is located on a City-owned property, Riverview Park, which has the potential to make mitigation activities more accessible and ultimately successful compared to privately-owned properties which can be more challenging and possibly more prone to failure, particularly when considering property owner coordination and property access. Finally, as demonstrated in Section 7.2, the Riverview Park mitigation site is a suitable location for achieving an overall functional lift with respect to water quality, hydrologic, and habitat critical area functions. Impacts proposed in the Honey Dew Creek buffer are within the May Creek drainage basin. In order to ensure no net loss of critical area function within that sub-basin, mitigation is proposed on-site within the Honey Dew Creek buffer. A conceptual mitigation plan for these impacts includes invasive species removal and native understory enhancement (Appendix G). 8.2 Wetland and Stream Buffer Mitigation Plan The mitigation plans are designed to restore and enhance wetland and wetland and stream buffer near the Cedar River and Honey Dew Creek. The plan accounts for utility maintenance needs, site topography, habitat connectivity, and vegetation height restrictions. The Riverview Park Mitigation Plan (Appendix F) includes notes that fulfill the mitigation and monitoring requirements of the RMC and provide clear direction for mitigation goals, performance standards, monitoring and maintenance protocols, and contingencies for the duration of the required five-year monitoring period. The final Honey Dew Creek Mitigation Plan (see Appendix G for conceptual plan) will include similar standards. Minimum mitigation needs (Table 12) were calculated based upon wetland and stream buffer impacts and the required minimum mitigation ratios presented in Section 5.2. The Watershed Company January 2018 53 Table 12. Calculation of mitigation needs for wetland and stream functioning buffer impacts. Impact Type Net Area of Impact (SF) Proposed Mitigation Ratio Mitigation Required (SF) Lower Cedar River Sub-basin Permanent 68 1:1 68 Conversion 15,948 0.5:1 7,974 Total: 8,042 May Creek Sub- basin Permanent 0 1:1 0 Conversion 2,838 0.5:1 1,419 Total: 1,419 Grand Total: 9,461 Required minimum buffer mitigation for the Project in Renton is 9,461 SF. As described in above, opportunity to fulfill this mitigation need exists on the City- owned Riverside Park property next to the Cedar River and in the Honey Dew Creek buffer. Mitigation for the Lower Cedar River sub-basin impacts, as proposed in the attached plan (Appendix F), consists of 8,100 SF of wetland and buffer enhancement within and adjacent to Wetland NRO2. This includes extensive blackberry removal and installation of a native shrub and tree area and a live stake planting area along an undefined channel within Wetland NRO2. Species proposed for installation include big leaf maple, Western red cedar, Pacific ninebark, Nootka rose, salmonberry, black cottonwood, red twig dogwood, Pacific willow, and Sitka willow, osoberry, Nootka rose and snowberry. In addition to the native plantings, buffer enhancement will include creation of eight habitat snags and one hinge-cut tree from trees assessed to be dead or dying. These mitigation activities are intended to increase native plant cover, decrease invasive species prevalence, improve native species diversity, and provide food and other habitat resources for wildlife. The plan will improve the function and value of a significant critical area located adjacent to the Cedar River in shoreline-associated wetland and overlapping wetland and stream buffer, and PSE Energize Eastside Project Renton Critical Areas Report 54 will ensure no net loss of critical area functions and values will occur as a result of the Project actions in Renton. A five year maintenance and monitoring plan is included in accordance with the requirements of RMC 4-3-050.L.3. See the Mitigation Plan in Appendix F for specific details. As previously mentioned, an additional mitigation plan for impacts within the May Creek sub-basin, in the Honey Dew Creek buffer is proposed (see Appendix G for conceptual plan). Anticipated mitigation activities include invasive species removal and restoration of a native understory in the stream buffer and steep slope areas. 8.3 Geologic Hazard Area Mitigation GeoEngineers has proposed mitigation strategies to minimize impacts to geologic hazard areas in the corridor in their analysis report (Appendix E). As stated previously, and in their report, with implementation of these strategies, proposed activities are not expected to impact the geologic hazard areas in the Honey Dew Creek and Cedar River drainage areas and are consistent with the management activities of the existing corridor. They recommend replacement planting with native shrubs within the Honey Dew Creek drainage to increase root strength after tree removal and to reduce impacts within the landslide hazard area. This recommendation will be incorporated into the final Honey Dew Creek mitigation plan. Pole Replacement Pole replacement activities are proposed in erosion hazard areas, landslide and steep slope hazard areas, and coal mine hazard areas. For pole replacement activities, the disturbed area will be stabilized using BMPs that reduce potential impacts including plant replacement, seeding, or hog fuel application in areas of bare soil and scattering chipped wood or tree debris. Soil removed from new pole excavations will be scattered into vegetation and away from landscaped areas. If the work area is wet or has standing water, driving mats will be used under all equipment and all soils excavated for pole installation will be removed from the site for offsite disposal. The requirements of a Sediment and Erosion Control Plan will be addressed in the Project-specific TESC Plan and Construction Stormwater Pollution Prevention Plan (CSWPPP). Additionally, for poles located in geological hazard areas or associated buffers, the old poles will be cut off approximately 1-2 feet below the ground surface and the remaining underground portion of each pole left in place to minimize ground disturbance. Vegetation Management Options for mitigation of vegetation management and tree removal in geologic hazard areas include limiting disturbance to these areas by large equipment The Watershed Company January 2018 55 (only by foot and hand-cutting with chainsaws), leaving cut stumps in place, and chipping or scattering tree debris where feasible. GeoEngineers recommends trees are felled across the fall line and left perpendicular to the slope if they are not chipped. Within the Honey Dew Creek drainage, replacement planting with native shrubs is recommended to increase root strength after tree removal and to reduce impacts within the landslide hazard area. Temporary Work Areas Where vegetation clearing is required to reestablish access on existing trails or old access routes, BMPs will be implemented. These BMPs may include, but are not limited to outsloping road surfaces, crowning road surfaces (where appropriate, such as at ridge tops and where roads climb gently inclined surfaces), and installing water bars or rolling dips at regularly spaced intervals to avoid concentrating surface water flow along the road surface. After construction, disturbed areas should be graded to a stable free-draining configuration, treated with appropriate erosion control measures, and seeded. Most, if not all, access routes can be abandoned following construction using erosion control measures and seeding. 9 CODE COMPLIANCE This Critical Areas Report has been prepared to support the City’s critical area review process and is intended to satisfy the requirements of the RMC 4-3-050 – Critical Areas Regulations. Because the Project is seeking land use approval for activities within the vicinity of critical areas, and proposes impacts to some critical areas, it is subject to the reporting requirements of RMC 4-3-050.F and 4- 8-120.D. This Critical Areas Report documentation, including appendices and the 2016 Delineation Report, is intended to substantially comply with the requirements for a stream and lake study, geotechnical study, habitat/wildlife assessment, and wetland assessment. The preceding sections identify and characterize critical areas, document appropriate buffers, and thoroughly evaluate the proposal and all probable impacts including an assessment of impacts of the development proposal on the identified critical areas, and contain an assessment of the impacts of the proposed critical area alterations and proposed compensation for such impacts. Mitigation sequencing has been followed as described in Section 6. Select specific critical areas code provisions applicable to this project are presented below (italicized), followed by a Project-specific response describing how the proposal complies with the standard. PSE Energize Eastside Project Renton Critical Areas Report 56 Proposed alterations to erosion hazard areas, landslide hazard areas, steep slope hazard areas, and associated buffers have been evaluated by the Project’s geotechnical experts, GeoEngineers. Their findings, including documentation of compliance with applicable code sections, are included as Appendix E, and are also incorporated in Sections 9.2 through 9.3 below. As noted in Section 4, the Cedar River is a Shoreline of the State and as such, it and its shorelines are subject to the requirements of the Renton SMP. The project has been designed to avoid all impacts, including native vegetation removal, within shoreline jurisdiction. PSE and Renton have sought and received documentation from the WA State Department of Ecology that proposed Project actions within the shoreline (spanning wires across the Cedar River) are exempt from the requirements of a Shoreline Substantial Development Permit (SSDP) or Shoreline Conditional Use Permit (email communication between J. Ding and S. Laverette 11.6.17). Proposed mitigation is located partially within shoreline jurisdiction. Mitigation actions consist strictly of restoration, which does not meet the definition of “development” in RCW 90.58.030. Therefore, the restoration should also be exempt from the requirements of a SSDP. 9.1 Wetlands and Streams All direct wetland and stream impacts are avoided. As described in Section 7, wetland and stream buffer impacts are limited to vegetation conversion as a result of tree removal, which will alter portions of the buffers from a forested to a shrub or herbaceous vegetation community; one new pole in the buffer of Wetland NRO2; and the replacement of three Lake Tradition Line poles with new poles with larger footprints. Mitigation is proposed for unavoidable wetland and stream buffer impacts pursuant to Ecology guidance for vegetation conversion impacts and RMC 4-3- 050.L Mitigation, Maintenance and Monitoring. The requirements of that code section have been considered in the preparation of the mitigation plan and are discussed in Sections 6 and 8 of this report. Specific requirements have been incorporated into the Riverview Park Mitigation Plan design and are documented in the Mitigation Plan notes (Appendix F). These requirements will also be included in the Honey Dew Creek Mitigation Plan, currently in a conceptual stage (Appendix G). Compliance with additional applicable wetland and stream provisions are described below. The Watershed Company January 2018 57 4-3-050.J.2.b Criteria for Administrative Approval of Utilities in Stream/Lake or Buffer New utility lines and facilities may be permitted to cross water bodies in accordance with an approved stream/lake study, if they comply with the following criteria: i. Fish and wildlife habitat areas shall be avoided to the maximum extent possible; and ii. The utility is designed consistent with one or more of the following methods: 1. (a) Installation shall be accomplished by boring beneath the scour depth and hyporheic zone of the water body and channel migration zone; or 2. (b) The utilities shall cross at an angle greater than sixty (60) degrees to the centerline of the channel in streams or perpendicular to the channel centerline; or 3. (c) Crossings shall be contained within the footprint of an existing road or utility crossing; and iii. New utility routes shall avoid paralleling the stream or following a down-valley course near the channel; and iv. The utility installation shall not increase or decrease the natural rate of shore migration or channel migration; and v. Seasonal work windows are determined and made a condition of approval; and vi. Mitigation criteria of subsection L of this Section are met. Response: The Project is proposed within an existing, managed utility corridor. PSE has avoided fish and wildlife areas to the maximum extent feasible on a pole-by-pole basis. Wires through the corridor cross perpendicular to all streams within the study area. All direct stream impacts are avoided and proposed buffer impacts are limited to vegetation conversion. Soils will remain intact below and adjacent to all streams. Project actions are not expected to increase or decrease the natural rate of shore migration or channel migration BMPs will be used to protect streams and minimize buffer impacts during construction and ongoing maintenance activities. During work within buffers, mats will be placed over existing vegetation where possible. Typically, crushed vegetation rebounds within one growing season resulting in only temporary impacts to vegetation. Post-construction, all disturbed areas will be re-vegetated, if necessary, and left to return to their natural state. Mitigation is provided pursuant to RMC 4-3-050.L (Appendices F and G). As no in-water work is proposed, seasonal work windows are not necessary for the Project. However, PSE will comply with any work windows which may be imposed by permitting agencies. 4-3-050.J.4 Criteria for Approving Wetland Alterations Wetland alterations may only be authorized after the City makes a written finding that the proposal is consistent with the following criteria: a. No Net Loss: Activities that adversely affect wetlands and/or wetland buffers shall include mitigation sufficient to achieve no net loss of wetland function and acreage and to achieve, where practicable, a net resource gain in wetlands over present conditions. The concept of “no PSE Energize Eastside Project Renton Critical Areas Report 58 net loss” means to create, restore and/or enhance a wetland so that there is no reduction to total wetland acreage and/or function. Response: No reduction of wetland acreage is proposed. As described in this report, mitigation is proposed which will adequately compensate for unavoidable buffer vegetation impacts and ensure no net loss of overall critical area buffer function. Proposed mitigation includes restoration of wetland and wetland buffer areas which will result in a net improvement of wetland functions in the Project area. d. Mitigation Ratios for Wetland Buffer Impacts: Compensation for wetland buffer impacts shall occur at a minimum one to one (1:1) ratio. Compensatory mitigation for buffer impacts shall include enhancement of degraded buffers by planting native species, removing structures and impervious surfaces within buffers, and other measures. Response: Buffer impacts are mainly limited to vegetation conversion. Minimal loss of buffer area to development (fill) will occur as a result of pole installation. Fill impacts will be mitigated at a 1:1 ratio. Since the magnitude of impact for vegetation conversion is less than permanent impacts, a reduced mitigation ratio is proposed using interagency guidance (Ecology et al. 2006). Interagency guidance for mitigating vegetation conversion impact (in wetlands, specifically) is to mitigate at one half the typical ratios for permanent impacts. Therefore, wetland and stream buffer impacts that result in a vegetation conversion will be mitigated at one-half the typical ratio (0.5:1). Mitigation includes invasive species removal and native plant installation in a wetland and wetland/stream buffer area. Restoration of a portion of the wetland, as well as some of its adjacent buffer, was deemed the most appropriate location for mitigation as it provides a direct and significant increase in critical area function. Temporary wetland and stream buffer impacts will be restored in-place at a 1:1 ratio. g. Location: Compensatory mitigation shall be provided on site or off site in the location that will provide the greatest ecological benefit and have the greatest likelihood of success. Mitigation shall occur as close as possible to the impact area, within the same watershed sub-basin, and in a similar habitat type as the permitted alteration unless the applicant demonstrates to the satisfaction of the Administrator through a watershed- or landscaped-based analysis that mitigation within an alternative sub-basin of the same watershed would have greater ecological benefit. Response: See Sections 7.2 and 8.1. Mitigation for impacts generated in the Lower Cedar River sub-basin, is proposed in a shoreline associated wetland and overlapping wetland and buffer area where the mitigation has the potential to provide the most benefit to the sub-basin. This location was selected based upon the location of project impacts, opportunity present, proximity to valuable critical area types, property ownership which will help ensure long-term management The Watershed Company January 2018 59 feasibility and ultimate success of the mitigation, and the value of the enhancement to overall critical area function in the corridor. Impacts generated within the May Creek sub-basin, within the buffer of Honey Dew Creek, will be mitigated for on-site in the Honey Dew Creek buffer. h. Protection: All mitigation areas whether on or off site shall be permanently protected and managed to prevent degradation and ensure protection of critical area functions and values into perpetuity. Permanent protection shall be achieved through protective covenant in accordance with this Section. Response: Mitigation is proposed within a City-owned park which will help ensure reliable access and coordination through the mitigation installation and monitoring period, as well as long-term protection. All mitigation areas shall be protected according to the permanent protection covenant deemed appropriate by the City. 9.2 Geologic Hazard Areas Compliance with applicable code provisions for geologic hazard areas has been described by the Project’s geotechnical experts. The complete geologic hazard evaluation is included in Appendix E. 4-3-050.G.5.f Protected Slopes Development is prohibited on protected slopes. Response: No development, or grading activity, is planned on protected slopes. Site activities include vegetation management and limited tree removal (associated with the pole replacement activities) within an existing utility right- of-way. Replacement of existing utility systems are exempted, provided the work does not increase the footprint by more than 10 percent and that restoration shall be conducted where feasible. 4-3-050.G.5.g Sensitive Slopes-Medium, High and Very High Landslide Hazards- High Erosion Hazards During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required. Response: Site activities include vegetation management and limited tree removal (associated with the pole replacement activities) on sensitive slopes. Weekly on-site inspections and reports documenting erosion control measures will be completed as required by the applicant. 4-3-050.G.5.i.ii Development Standards for Geologically Hazardous Areas – Coal Mine Hazards Found during Construction Any hazards found during any development activities shall be immediately reported to the Development Services Division. Any coal mine hazards shall be mitigated prior to PSE Energize Eastside Project Renton Critical Areas Report 60 recommencing construction based upon supplemental recommendations or reports by the applicant’s geotechnical professional. During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required Response: Any coal mine hazards found during the proposed vegetation management and tree removal activities associated with the pole replacement activities will be immediately reported to the Development Services Division. Any identified coal mine hazards will be mitigated prior to recommencing any activities based upon supplemental recommendations or reports by the applicant’s geotechnical professional. Weekly on-site inspections and reports documenting erosion control measures will be completed by the applicant. 9.3 Wellhead protection areas 4-3-050.G.8– Development Standards for Wellhead Protection Areas Any potential risks to groundwater Wellhead Protection Zones found during any development activities shall be immediately reported to the Development Services Division. Any risk to groundwater wellhead protection zones shall be mitigated prior to recommencing construction based upon supplemental recommendations or reports by the applicant’s geotechnical professional. During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required. Response: No construction dewatering is planned within the project area including Wellhead Protection Zones. Spill Prevention Control and Countermeasures (SPCC) and Temporary Erosion and Sediment Control (TESC) Plans will be implemented to address potential construction related contaminant handling associated within Wellhead Protection Zones. Potential contaminant impacts to Wellhead Protection Zones associated with removal and proposed vegetation management and tree removal activities associated with the pole replacement activities would be immediately reported to the Development Services Division. Any risks to Wellhead Protection Zones associated with the project will be mitigated prior to recommencing any activities based upon supplemental recommendations or reports by the applicant’s geotechnical professional. Weekly on-site inspections and reports documenting erosion control measures will be completed by the applicant. 9.4 Habitat conservation areas Compliance with applicable code provisions for habitat conservation areas is described below. The Watershed Company January 2018 61 4-3-050.G.6.d Alterations Require Mitigation The Administrator may approve mitigation to compensate for adverse impacts of a development proposal to habitat conservation areas through use of a federally and/or state certified mitigation bank or in-lieu fee program. Response: Adverse impacts to HCAs are not expected. The one new pole added to the Cedar River HCA will be offset by the removal of three existing poles in the same area. Furthermore, mitigation proposed for unavoidable wetland and stream buffer impacts pursuant to RMC 4-3-050.L Mitigation, Maintenance and Monitoring will enhance the high value wetland habitat adjacent to the Cedar River and is expected to further improve habitat conditions. 10 DISCLAIMER The information contained in this report is based on the application of technical guidelines currently accepted as the best available science. All discussions, conclusions and recommendations reflect the best professional judgment of the author(s) and are based upon information available at the time the study was conducted. All work was completed within the constraints of budget, scope, and timing. The findings of this report are subject to verification and agreement by the appropriate local, state and federal regulatory authorities. No other warranty, expressed or implied, is made. R EFERENCES Ding, Jill and S. Leverette. Email Communication. 11.6.17. Environmental Science Associates (ESA). May 2017. Energize Eastside Project: Phase 2 Draft Environmental Impact Statement. Prepared for the Cities of Bellevue, Newcastle, Redmond, and Renton. Available online: http://www.energizeeastsideeis.org/library.html#phase2deis GeoEngineers. 2017. Revised Targeted Critical Areas Geologic Hazard Evaluation: Energize Eastside Project in Renton, WA. Prepared for PSE. IUCN SSC Amphibian Specialist Group. 2015. Anaxyrus boreas. The IUCN Red List of Threatened Species 2015: e.T3179A53947725. Accessed 20 June 2017: http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T3179A53947725.en. PSE Energize Eastside Project Renton Critical Areas Report 62 Lewis, J.C. and J.M Azerrad. 2003. Pileated Woodpecker. Pages 29-1 – 26-9 in E. Larsen, J.M. Azerrad, N. Nordstrom, editors. Management Recommendations for Washington’s Priority Species, Volume IV: Birds. Washington Department of Fish and Wildlife, Olympia, Washington, USA Puget Sound Energy. (n.d.) Avian Protection Program Brochure. Accessed 12 July 2017: https://pse.com/aboutpse/PseNewsroom/MediaKit/4483_Avian_program_brochu re.pdf The Watershed Company. May 2016a. City of Renton Critical Areas Delineation Report: Puget Sound Energy – Energize Eastside Project. Prepared for PSE. Available online: http://www.energizeeastsideeis.org/library.html. The Watershed Company. May 2016b. City of Renton Tree Inventory Report: Puget Sound Energy – Energize Eastside Project. Prepared for PSE. Available online: http://www.energizeeastsideeis.org/library.html. Washington Department of Ecology (Ecology), U.S. Army Corps of Engineers Seattle District, and U.S. Environmental Protection Agency Region 10. March 2006. Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance (Version 1). Washington State Department of Ecology Publication #06-06-011a. Olympia, WA. Washington Department of Fish and Wildlife (WDFW). 2008. Priority habitats and species list. Olympia, WA 295 pp. Washington Department of Fish and Wildlife (WDFW). 2013. PHS Statewide List and Distribution by County Excel Spreadsheet. Accessed September 2017: http://wdfw.wa.gov/conservation/phs/list/. Washington Department of Fish and Wildlife (WDFW). 2017. SalmonScape. Accessed October 2017: http://apps.wdfw.wa.gov/salmonscape/. A P P E N D I X A Critical Area Assessment Maps B l a c k R i v e r E a s t L a k eW a s h i n g t o n- B e l l e v u e S o u t h E a s t L a k e W a s h i n g t o n - R e n t o n L o w e rC e d a rR i v e r M a y C r e e kW a t e r- L a k eW a s h i n g t o n W e s t L a k eW a s h i n g t o n -S e a t t l e S o u t h 1 2 3 4 5 6 7 8910 11 Newcastl e Renton Newcastle King County Renton King County Renton Segment of PSE Route 1 PSE, TWC PSE Route outside of Renton SegmentPSE Map Page Extent (numbered)TWC Basin BoundaryKC TrailsCON Road CenterlinesCOB City LimitKC P S E E E 2 3 0 - R E N T O N C R I T I C A L A R E A A S S E S S M E N T M A P - C O V E R PA G E §¨¦405 §¨¦90 ¬«169 0 750 1,500 Feet o Notes:1. Critical areas were defined within a 100' corridor along the existingpowerline corridor.2. Map pages highlighted are where critical areas, as designated in RentonMunicipal Code, are mapped within the Renton corridor. All other map pageswere omitted.3. Only those steep slopes designated as priority through geotechnical fieldinvestigation are mapped within the corridor. Please refer to discussion inCritical Areas Report. ¬«900 Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), and HDR. Aerial imagery from PSE, 2011. King County 3/6 NEWPOR T C T N E 12 5 T H A V E S E NE W P O R T C T N E NE 21 S T S T P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o1 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 3/5 3/5 STREAM M R 0 1 [ H O N E Y DEW CREE K ] P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o2 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV NE 17TH PL P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o3 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV Shoreline Jurisdiction based on approximate extent of Cedar Northwetland boundary. 1/1 CEDAR NORTHWETLAND -ESTIMATED P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o4 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV WETLAND NR02 CEDARNORTH WETLAND- ESTIMATED MAPLE VALLE Y H W Y CEDAR RIVER [DELINEATED SOUTHERN EXTENT ONLY] S T R E AM N R 0 2 P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o5 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV WETLAND NR03 WETLAND NR02 RIVERVIEW PARK WALK CEDAR RI V E R T R A I L STREAM NR02P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o6 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 0/9 SE 8TH ST HARRINGTON PL SEHARRINGTON PL SEKIRKLAN D A V E S E P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o7 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 0/8 0/8 0/8 0/8 0/9 0/9 0/9 0/10 0/10 0/10 WETLAND NR04 HARRI N G T O N P L S ESE 8TH STSE 8TH PLSE 10TH STHARRIN G T O N P L S E HARRIN G T O N P L S E 115-0/8 115-0/8 115-0/9 115-0/9 115-0/9 115-0/10 115-0/10 115-0/10 STREAM N R 0 2 P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o8 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 0/7 WETLAND NR01 WETLAND NR05 NR05 -ESTIMATED STREAM N R 0 1[GINGER C R E E K ] P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o9 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 0/6 WETLAND NR01 WETLANDNR05 WETLAND NR05 NR05 -ESTIMATED P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o10 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV 0/3 0/4 0/4 0/3 0/3 0/3 0/4 0/4 0/4 TALBOT WETLAND- ESTIMATED BEACON WAY SACCESS R D 115-0/3 115-0/3 115-0/3 115-0/4 115-0/4 115-0/4 P S E E E 2 3 0 - R E N TO N C R I T I C A L A R E A A S S E S S M E N T M A P Data sources: Puget Sound Energy (PSE), The Watershed Company (TWC), City of Renton (COR), King County (KC), Washington Department of Fish and Wildlife (WDFW) and HDR. Aerial imagery from PSE, 2011. §¨¦405 Renton 0 20 40 Feet o11 Notes:1. Critical areas were defined within a 100'corridor along the existing transmission linecorridor.2. Access routes shown at typical width of 20 feet.3. Determined in the field by geotechnicalconsultant. See discussion in Critical AreasReport.4. Wellhead Protection Areas cover most of theproject area, and are not shown for mappingpurposes. See CAIA report for impacts. UV900 UV169 Newcastle CriticalAreasDelineated Stream BoundaryTWC Delineated Wetland BoundaryTWC Estimated Wetland BoundaryTWC StreamTWC WetlandTWC Estimated WetlandTWC Limit of Functioning Buffer AreaTWC Combined Functioning Wetland/Stream BufferAreaTWC- white shading Priority Steep Slopes3 TWC Erosion HazardCOR Priority Landslide Hazard AreasCOR Coal Mine HazardCOR Seismic HazardCOR Shoreline JurisdictionTWC FloodwayCOR FloodplainCOR ....Priority HabitatWDFW ImpactsWiresPSE Lake Tradition 115k WiresPSE !?Existing Poles to be RemovedPSE !H Existing Poles to be RetainedPSE Wire ZonePSE Managed Right-of-Way PSE Maintained Legal ROWPSE-pale yellow shading Proposed Access Routes2 PSE %%,Proposed Pole FootprintsPSE %%,Proposed Lake Tradition Pole FootprintsPSE #*Proposed Stringing SitesHDR Study AreaTWC City LimitKC D Trees to RemoveTWC D Dead Trees to RemoveTWCV A P P E N D I X B 2016 Delineation Study C ITY OF R ENTON C RITICAL A REAS D ELINEATION R EPORT Puget Sound Energy – Energize Eastside Project Prepared for: Jens Nedrud Puget Sound Energy 355 10th Avenue NE Mail Stop: EST03W48 Bellevue, WA 98004 Prepared by: May 2016 The Watershed Company Reference Number: 111103 The Watershed Company Contact Person: Jennifer Creveling, Senior Biologist or Katy Crandall, Ecologist Cite this document as: The Watershed Company. May 2016. City of Renton Critical Areas Delineation Report: Puget Sound Energy – Energize Eastside Project. Prepared for PSE. The Watershed Company May 2016 i T ABLE OF C ONTENTS Page # 1 Introduction ......................................................................................... 1 1.1 Background and Purpose .................................................................................. 1 1.2 Methods ............................................................................................................ 4 2 Site Description .................................................................................. 5 3 Critical Areas ....................................................................................... 5 3.1 Wetlands ........................................................................................................... 6 3.2 Streams ............................................................................................................ 7 3.3 Wildlife and Habitat ........................................................................................... 8 3.4 Critical Area Classifications and Standard Buffers........................................... 11 3.4.1 Wetlands ........................................................................................................... 11 3.4.2 Streams ............................................................................................................. 11 4 Mitigation Opportunities .................................................................. 12 4.1 Segment M (Honey Dew Creek Ravine) .......................................................... 12 4.2 Segment N (near Talbot Hill Substation) ......................................................... 12 Appendix A Critical Area Delineation Maps Appendix B Wetland Determination Data Forms Appendix C Wetland Rating Forms PSE 230kV Route Renton Delineation Report City of Renton Critical Areas Delineation Report - II L IST OF F IGURES Figure 1. Map of proposed Oak and Willow routes from the Energize Eastside website. The Oak route is depicted in green while the Willow route variation is shown in orange. ...................................................................................... 2 Figure 2. Overview of the study area corridor in the City of Redmond including the southern portion of Segment M and Segment N. ...................................... 3 Figure 3. Location of osprey nest in the vicinity of Segment N in the City of Renton. .... 10 Figure 4. General area (yellow) where mitigation opportunities exist in Segment M ..... 12 Figure 5. General area (yellow) where mitigation opportunities along Segment N. ....... 13 L IST OF T ABLES Table 1. Wetland rating and associated buffer width. ................................................... 11 Table 2. Summary of stream classifications and associated standard buffer widths. .... 11 The Watershed Company May 2016 1 C ITY OF R E NTON D ELINEATION R EPORT PUGET SOUND ENERGY – ENERGIZE E ASTSIDE PROJECT 1 INTRODUCTION 1.1 Background and Purpose The purpose of this report is to identify and document potential critical areas associated with Puget Sound Energy’s (PSE’s) Energize Eastside project. The Energize Eastside project proposes to build a new electric substation and higher capacity transmission lines to serve homes and businesses on the Eastside. Current route options include ‘Oak’ and ‘Willow’ routes that will extend from Redmond to Renton (Figure 1). Each route option includes a set of PSE-labeled segments. The Oak route comprises Segments A, C, E, G2, I, K2, M, and N. The Willow route comprises Segments A, C, E, J, M, and N. This report addresses critical areas located along the proposed routes in the City of Renton, and includes PSE-labeled Segment N and a portion of Segment M1 (Figure 2). The length of the study area corridor in the City of Renton is approximately 3.7 miles beginning south of May Creek and continuing south to the Talbot Hill substation (Figure 2). At the direction of PSE, the study area excluded the lower portion of the Cedar River ravine because there are no pole placement locations nor anticipated PSE development in this area. In this location, the study area was defined as follows: on the south side of the ravine, survey limits included the area approximately 425 feet north-northwest beyond the existing structure(s); and on the north side of the ravine, survey limits included the area approximately 250 feet south-southeast beyond the existing structure(s). The study area corridor includes two existing 115 kV transmission lines spaced approximately 50 feet apart on center. Each line is composed of three conductors (wires) connected to H-frame pole structures. The study area corridor is approximately 100 feet wide. 1 PSE Segments M and N comprise Phase 2 Draft Environmental Impact Statement (DEIS) Segment 3. PSE 230kV Route Renton Delineation Report 2 Figure 1. Map of proposed Oak and Willow routes from the Energize Eastside website. The Oak route is depicted in green while the Willow route variation is shown in orange. The Watershed Company May 2016 3 Figure 2. Overview of the study area corridor in the City of Renton including the southern portion of Segment M (red) and Segment N (green). PSE 230kV Route Renton Delineation Report 4 1.2 Methods Limits of the study area were determined in the field using aerial maps, GPS, and by measuring 25 feet out from the center of each pole set. Public-domain information on the study area corridor was reviewed for this critical areas study. These sources include USDA Natural Resources Conservation Service (NRCS) soil maps, U.S. Fish and Wildlife Service National Wetland Inventory (NWI) maps, Washington Department of Fish and Wildlife interactive mapping programs (PHS on the Web and SalmonScape), City of Renton’s online mapping application (COR Maps), and King County’s GIS mapping website (iMAP). The study area corridor was evaluated for wetlands using methodology from the Regional Supplement (Corps 2010). The wetland boundary was determined on the basis of an examination of vegetation, soils, and hydrology. Areas meeting the criteria set forth in the Regional Supplement were determined to be wetland. Soil, vegetation, and hydrologic parameters were sampled at several locations along the wetland boundary to make the determination. Data were recorded at three of these locations. Data sheets are included in Appendix B. Updates to the City of Renton’s critical areas regulations occurred after field work was conducted in the City of Renton. Renton’s wetland classification system changed as a part of these updates. Delineated wetlands have been re- classified using the 2014 Rating System (Hruby) currently cited in the Code, based on observations of site conditions and aerial photos. Wetland Rating Forms and Figures are included in Appendix C. Watercourses were determined to be streams if they met the definition provided by the City of Renton. The center-lines of streams in the study area were recorded in the field. Streams were classified according to the Renton Municipal Code. Wetland boundaries, stream center-lines, data points, and other features (such as culverts) were GPS-located using a hand-held Trimble Geo-XH unit. Following field location, the GPS data was differentially corrected using GPS Pathfinder Office and exported into ESRI ArcGIS software for mapping. Stream and wetland delineation maps are included in Appendix A. Incidental wildlife observations and detections were recorded during field studies and summarized in Section 3.3 of this report. Possible mitigation opportunities were noted during field studies. The approximate extent of these areas is shown on aerial photos included in Section 5 of this report. The Watershed Company May 2016 5 2 SITE DESCRIPTION The study area corridor in the City of Renton is dominated by urban land uses. The majority of the corridor passes through parcels zoned residential, commercial, or industrial. Within the residential areas, the corridor passes through several distinct neighborhoods; from north to south, these include Glencoe, Honey Creek Ridge, Sunset, Liberty Ridge, and Shadow Hawk. The largest patch of remaining undeveloped land is located adjacent to the Cedar River and zoned Resource Conservation (RC). The study area corridor is primarily located in the Cedar-Sammamish Watershed (WRIA 8). Within this watershed, the north end of the study area drains to the May Creek basin while the remainder is located in the Lower Cedar River drainage basin. At the southern end of the corridor, near the Talbot Hill substation, the study area drains into the Black River basin of the Duwamish- Green Watershed (WRIA 9). The study area corridor in the City of Renton is located in Township 23N, Range 05E, Sections 4, 9, 16, 20, and 21. Most of the study area corridor in the City of Renton has been developed. Vegetation in residential, commercial, and industrial areas can be generally described as maintained yards or landscaped. Remaining vegetated areas are often dominated by invasive plants including Himalayan blackberry and reed canarygrass. Forested patches are limited to topographically low regions near the Cedar River and Honey Dew Creek. 3 CRITICAL AREAS A total of one wetland and four streams are located along the proposed Energize Eastside corridor in the City of Renton. All are located in the Cedar-Sammamish Watershed (WRIA 8). Sign or presence of any wildlife species or habitat areas that may be regulated by the City were also noted and are described in this section. For the purposes of this study, the nomenclature used to identify critical areas has been based on the PSE segment in which a feature is located, and the local jurisdiction. Critical areas were then numbered sequentially, in the order in which they were inventoried. For example, the first wetland inventoried as a part of this study on Segment N in Renton is called “NR01.” PSE 230kV Route Renton Delineation Report 6 3.1 Wetlands Wetland NR01 Wetland NR01 is a slope wetland located near the southern end of the study area, between SE Cedar Ridge Drive and the Shadow Hawk neighborhood (Appendix A, Page No. 31). Vegetation is dominated by palustrine scrub-shrub and palustrine emergent vegetation classes. Common plants observed include hardhack spirea and reed canarygrass. Sampled wetland soils (Appendix B; DP- 1) were a gravelly loam and met the criteria for hydric soil indicator Redox Dark Surface (F6). Primary hydrology indicators were not observed at the test pit, but saturation and/or surface water was present in small depressions in the wetland during field investigations. Conditions at the data point met the criteria for two secondary hydrology indicators. Wetland NR01 is primarily supported by groundwater and supplemented by surface water and precipitation. This wetland is rated as a Category III wetland. Unmapped Wetland Areas Two wetland areas are mapped on COR maps underneath the powerlines between the Cedar River Trail and the Cedar River. As described in the Methods section above, this wetland area was not verified or classified as part of this study. There are neither pole placement locations nor anticipated PSE development in this area. Their approximate locations have been sketched onto the Critical Areas Maps (Appendix A). Non-wetland Areas A possible wetland feature is mapped by NWI and the City of Renton on a parcel located west of Monroe Avenue NE (parcel number 1623059059). The parcel is undeveloped. A review of the City’s online public records indicates this area, known as Upper Balch Pit, was a permitted sand/gravel pit from 1962 to 1982; since 1982, the site has been an upland fill and reclamation site. In 2010, a wetland reconnaissance technical memorandum documenting no wetlands on the property was reviewed and approved by the City (City of Renton, File # LUA 10-056, ECF, SP). Field investigations (DP-3, Appendix B) support this conclusion. While some surface water ponding may occur during wet months, the site does not meet wetland criteria. Off-site Wetlands At least two wetlands appear to be located near the powerline corridor, but outside of the designated study area on Segment N between SE Cedar Ridge Drive and the Cedar River. Their approximate locations have been sketched onto the Critical Area Delineation Maps (Appendix A). These features were not thoroughly investigated or rated during field work activities, but are mentioned here because they may have regulated buffers that extend into the project area. The Watershed Company May 2016 7 Subsequent field work efforts may be needed to address these off-site features if project impacts are proposed in the vicinity. 3.2 Streams The streams discussed below have been mapped and classified by the City of Renton in the City of Renton’s online interactive mapping application (COR Maps). Stream MR01 (Honey Dew Creek) Stream MR01, also known as Honey Dew Creek, is located at the north end of the study area corridor (Appendix A, Page No. 6). It flows northwest through the corridor and drains to May Creek located approximately 0.6 mile downstream. Honey Dew Creek is located in a forested ravine. There are small pockets of riverine wetland vegetation within the OHWM of the creek. It is approximately 10 feet wide through the study area corridor. COR Maps classifies Honey Dew Creek as Type F, or fish-bearing, at this location. Field observations are consistent with this classification. Stream NR01 (Ginger Creek) Stream NR01, also known as Ginger Creek, is located east of Wetland NR01 (Appendix A, Page No. 30). Ginger Creek flows generally north through the study area before draining into the Cedar River, approximately 0.3 mile downstream. It is mapped by COR Maps as originating southeast of the study area in Cascade Park. Through the study area, Ginger Creek is located in a very steep-sided ravine. The bed is made up of coarse cobble and the average width is approximated at 8 to 10 feet. COR Maps classifies this stream as Type Np, or non-fish bearing perennial. During the summer field investigations, no flow was observed in Ginger Creek in the study area. This is not likely characteristic of the stream, as it was visited near the end of summer during a drought. The Seattle office of the National Weather Forecast Office reported drier than normal conditions summer months in May through July (-1.36 inches departure from normal precipitation). Stream NR01 should still be classified as Type Np, as Renton Municipal Code specifies that Type Np waters can include intermittent dry portions of the perennial channel below the uppermost point of perennial flow during years of non- normal rainfall. If pole placements are to be placed here, it may be prudent to re- visit the creek on a non-drought year to assess whether the stream should be re- typed as Type Ns, or non-fish bearing seasonal. PSE 230kV Route Renton Delineation Report 8 Stream NR02 Stream NR02 is a seasonal stream that flows north through, or adjacent to, the study area corridor (Appendix A, Page No. 28, 29 and 30). It crosses or approaches the corridor at two locations. At the upstream location, it is located approximately 250 feet east of Ginger Creek, west of the Shadow Hawk neighborhood. At this location, the stream channel is just beginning to form and is poorly defined. The channel here was dry and estimated at approximately 2 feet wide. Banks are predominantly vegetated with Himalayan blackberry. The bed is made up of mostly dirt with some rock and cobble present. An off-site wetland, located just south of this area, appears to contribute flow to this stream during wetter months. Downstream, near the Cedar River Trail, Stream NR02 approaches the study area corridor again. Here, the stream channel flows in distinct banks and the bed contains rock and gravel. Average width of the stream at this location is 3 feet. This portion of the channel was flowing during the site visit. COR Maps classifies this stream as Type Ns, or non-fish bearing seasonal. Field observations are consistent with this classification. Cedar River While the area immediately adjacent to the Cedar River was specifically excluded from this study area as described in Methods section above, the Cedar River is a prominent critical area located in the subject powerline corridor and is therefore discussed briefly in this section. The Cedar River is a regulated Shoreline of the State. Aerial photo measurements indicate that the width of the Cedar River under the powerline corridor is generally between 70 to 90 feet. Fish use in the Cedar River is well documented and incudes bull trout, coho salmon, sockeye salmon, Chinook salmon, steelhead trout, kokanee, and resident cutthroat trout (SalmonScape and PHS on the Web). 3.3 Wildlife and Habitat The City of Renton regulates habitats that have a primary association with species listed by the Federal government or State of Washington as endangered, threatened, sensitive, and/or local importance as critical areas. The City also considers areas designated as priority habitats in the Priority Habitat and Species Program of the Washington State Department of Fish and Wildlife as habitat conservation areas. Washington State Priority Habitat and Species (PHS) maps were reviewed for the project vicinity. In addition to the salmonid species documented in the Cedar River and Honey Dew Creek, PHS maps depict forested patches adjacent to the The Watershed Company May 2016 9 Cedar River as Biodiversity Areas and Corridors. No other PHS features are mapped in or near the powerline corridor. Significant wildlife observations were recorded during field investigations. A pileated woodpecker was in a forested patch near the Honey Dew Creek ravine. A bald eagle was also observed flying overhead in this general area. More significantly, an active osprey nest was observed near the study area corridor on Segment N. The nest was located in a cell tower (Figure 3) southwest of Cedar Ridge Drive SE. Two adults and one juvenile osprey were visible using the nest on several occasions during the summer field visits. PSE 230kV Route Renton Delineation Report 10 Figure 3. Location of osprey nest in the vicinity of Segment N in the City of Renton. Habitat in the study area is limited to forested patches in topographically low areas (ravines) associated with Honey Dew Creek and the Cedar River. These forested areas are typically dominated by deciduous trees including red alder and bigleaf maple in the canopy. Habitat located in and adjacent to the study area corridor may have the potential to support regulated wildlife species. Osprey nest location The Watershed Company May 2016 11 3.4 Critical Area Classifications and Standard Buffers Critical areas in the City of Renton are regulated in the Renton Municipal Code (RMC), Title IV Development Regulations, Chapter 3 Environmental Regulations and Overlay District, 4-3-050 Critical Areas Regulations. Shorelines of the State in the City of Renton are regulated under the Renton Shoreline Master Program (RMC 4-3-090). 3.4.1 Wetlands According to RMC 4-3-050-G.9, wetlands are classified based on the 2014 Rating System (Hruby). Wetland buffers are measured from the wetland edge and are based upon the wetland rating, associated habitat score, and impact of land use. The adjacent land use would not be considered low intensity, therefore the buffer width for “all other land uses” applies. Wetland NR01 rates as “moderate” for habitat functions. The following table shows the rating for Wetland NR01 and its associated standard buffer width. Table 1. Wetland rating and associated buffer width. Wetland Name 2014 Ecology Wetland Rating Category Standard Buffer Width (ft) Water Quality Hydrology Habitat Total NR01 5 6 7 18 III 100 Wetland delineations are valid in the City of Renton for up to five years from the study date of completion. This period may be extended if it can be confirmed that on-site conditions have not changed. 3.4.2 Streams Streams are classified based on Washington State’s Permanent Water Typing System (WAC 222-16-030, RMC 4-3-050-G.7.a). Status as Shoreline of the State, permanence of flow, and presence of fish or fish habitat are considered to make the stream class determination. Stream buffers are measured from the ordinary high water mark (OHWM). Shorelines of the state (Type S streams) are regulated under the City of Renton SMP (RMC 4-3-090); all other streams are regulated under RMC 4-3-050 Critical Areas Regulations. A summary of stream types and buffer widths is provided in Table 2, below. Table 2. Summary of stream classifications and associated standard buffer widths. Stream Name Stream Type Standard Buffer Width (ft) MR01 (Honey Dew Creek) Type F 115 NR01 (Ginger Creek) Type Np 75 NR02 Type Ns 50 Cedar River Type S, Shoreline 100 PSE 230kV Route Renton Delineation Report 12 4 MITIGATION OPPORTUNITIES Mitigation opportunities located in the study area were noted during field investigations. These areas include degraded/disturbed wetland and stream critical areas and their buffers; all are located under existing powerline corridors. The degraded and disturbed areas are dominated by invasive species such as reed canarygrass and Himalayan blackberry. Any proposed revegetation would need to adhere to vegetation height limits prescribed by PSE standards. Special care would also need to be given in areas with steep slopes. Locations where mitigation opportunities exist have been briefly summarized below. 4.1 Segment M (Honey Dew Creek Ravine) Mitigation opportunities are present in Segment M along the Honey Dew Creek Ravine (on City of Renton parcels 0423059342 and 0423059035). This site includes Honey Dew Creek (Stream MR01). Figure 4. General area (yellow) where mitigation opportunities exist in Segment M 4.2 Segment N (near Talbot Hill Substation) The area that appears to provide the largest opportunity for mitigation within the City of Renton is the segment of the corridor between Cedar Ridge Drive SE The Watershed Company May 2016 13 and the Cedar River trail (private parcels 7701570000 and 7701590000; PSE parcels 2023059001, 2023059050, and 1623059012; and the City of Renton parcel 2123059003). The site includes portions of Streams NR01 (Ginger Creek), NR02, Wetland NR01, and critical area buffers. Figure 5. General area (yellow) where mitigation opportunities along Segment N. PSE 230kV Route Renton Delineation Report 14 R EFERENCES City of Renton. (2015). City of Renton Municipal Code. Retrieved December 31, 2015, from: http://www.codepublishing.com/WA/Renton/#!/RentonNT.html City of Renton GIS Department. (2015) City of Renton (COR) Maps. Retrieved from December 31, 2015, from the City of Renton: http://rp.rentonwa.gov/SilverlightPublic/Viewer.html?Viewer=COR-Maps Hruby, T. 2014. Washington State Wetland Rating System for Western Washington: 2014 Update. Publication #14-06-029. Olympia, WA: Washington Department of Ecology. Kaufman, F. 2010. Upper Balch Pit Grade & Fill, File No. LUA-10-056, ECF, SP. Office of the Hearing Examiner, City of Renton. King County GIS Center. (2015). King County iMap Interactive Mapping Tool. Retrieved December 31, 2015, from King County GIS Center: http://www.kingcounty.gov/operations/GIS/Maps/iMAP.aspx U.S. Army Corps of Engineers (Corps). 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Washington Mountains, Valleys, and Coast Region, Version 2.0 (Regional Supplement). Wetlands Regulatory Assistance Program. U.S. Army Engineer Research and Development Center, Environmental Laboratory. ERDC/EL TR-10-3. [USDA] U.S. Department of Agriculture. (2015). Web Soil Survey. Retrieved December 31, 2015, from Natural Resources Conservation Service: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx [USFWS] U.S. Fish and Wildlife Service. (2015). Wetlands Mapper. Retrieved December 31, 2015, from National Wetlands Inventory: http://www.fws.gov/wetlands/Data/Mapper.html [WDFW] Washington Department of Fish & Wildlife. (2015). PHS on the Web. Retrieved December 31, 2015, from Priority Habitats and Species: http://wdfw.wa.gov/mapping/phs/ [WDFW] Washington Department of Fish & Wildlife. (2015). SalmonScape web application. Retrieved December 31, 2015, from WDFW: http://apps.wdfw.wa.gov/salmonscape/ The Watershed Company May 2016 A PPENDIX A Critical Area Delineation Maps King County Renton M 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM1 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. King County Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM2 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. King County King County Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM3 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. King County Renton Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM4 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. King County Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM5 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M115'STREAM MR01 (Honey Creek) Stream Critical Area BufferTWC Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM6 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM7 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM8 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM9 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM10 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM11 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM12 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM13 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM14 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM15 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM16 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM17 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM18 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM19 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM20 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM21 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM22 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM23 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM24 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton M N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM/N25 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTM/N26 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N WETLANDUNNAMED(COR)200'Ce dar River Stream Wetland Critical Area BufferTWC 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN27 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. 2. Wetlands shown were mapped by City of Renton (2012), but were not investigated as part of the PSE study. WETLANDUNNAMED(COR) Renton N WETLANDUNNAMED(COR) 50'STREAMNR02Stream Wetland Critical Area BufferTWC Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN28 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. 2. Wetlands shown were mapped by City of Renton (2012), but were not investigated as part of the PSE study. Renton N WETLANDUNNAMEDSTREAMNR02 Stream Wetland Critical Area BufferTWC Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN29 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N WETLANDUNNAMED 50'75'STREAM NR02 STREAMNR01(GingerCreek) Stream Wetland Critical Area BufferTWC Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN30 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. 2. Observed while in the field and sketched, but not delineated. Renton N DP-1 DP-2 WETLANDNR01 WETLANDUNNAMED 100' Data PointTWC Wetland Critical Area BufferTWC Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN31 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. 2. Observed while in the field and sketched, but not delineated. Renton N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN32 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN33 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN34 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. Renton N Existing Pole LocationPSE 100' Screening LimitTWC City LimitKC P S E E E 2 3 0 - C R I T I C A L A R E A S A S S E S S M E N T M A P 0 25 50 Feet PAGE NO. SEGMENTN35 Data sources: Puget Sound Energy, The Watershed Company, and King County. Aerial imagery from PSE. Notes: 1. Category IV wetlands that are less than 2,500 SF in area, do not have a buffer. The Watershed Company May 2016 A PPENDIX B Wetland Determination Data Forms US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version 750 Sixth Street South Kirkland, Washington 98033 (425) 822-5242 watershedco.com WETLAND DETERMINATION DATA FORM Western Mountains, Valleys, and Coast Supplement to the 1987 COE Wetlands Delineation Manual Project Site: Segment N, parcel number 2123059003 Sampling Date: 7/8/2015 Applicant/Owner: Puget Sound Energy Sampling Point: DP- 1 Investigator: Katy Crandall, Rose Whitson City/County: Renton Sect., Township, Range: S 16 T 23 R 05 State: WA Landform (hillslope, terrace, etc): Hillslope Slope (%): ~5 Local relief (concave, convex, none): Concave Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: AgC – Alderwood gravelly sandy loam, 8-15% slopes NWI classification: NA Are climatic/hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are “Normal Circumstances” present on the site? ☒ Yes ☐ No (If needed, explain any answers in Remarks.) Are Vegetation☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are Vegetation☐, Soil ☐, or Hydrology ☐ naturally problematic SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampling Point within a Wetland? Yes ☒ No ☐ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Wetland NR01 VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5m diam.) Absolute % Cover Dominant Species? Indicator Status Dominance Test Worksheet 1. Number of Dominant Species that are OBL, FACW, or FAC: 2 (A) 2. 3. Total Number of Dominant Species Across All Strata: 2 (B) 4. = Total Cover Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) Sapling/Shrub Stratum (Plot size: 3m diam.) 1. Spiraea douglasii 15 Y FACW Prevalence Index Worksheet 2. Total % Cover of Multiply by 3. OBL species x 1 = 4. FACW species x 2 = 5. FAC species x 3 = 15 = Total Cover FACU species x 4 = UPL species x 5 = Herb Stratum (Plot size: 1m diam.) Column totals (A) (B) 1. Phalaris arundinacea 95 Y FACW 2. Prevalence Index = B / A = 3. 4. Hydrophytic Vegetation Indicators 5. ☒ Dominance test is > 50% 6. ☐ Prevalence test is ≤ 3.0 * 7. Morphological Adaptations * (provide supporting 8. ☐ data in remarks or on a separate sheet) 9. ☐ Wetland Non-Vascular Plants * 10. ☐ Problematic Hydrophytic Vegetation * (explain) 11. 95 = Total Cover * Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic Woody Vine Stratum (Plot size: ) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. = Total Cover % Bare Ground in Herb Stratum: Remarks: DP- 1 US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version SOIL Sampling Point – DP-1 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-12 5 YR 3/1 97 5 YR 3/4 3 C M Gravelly loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains 2Loc: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Other (explain in remarks) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☒ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: ________________________________________ Depth (inches): _____________________________________ Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply): Secondary Indicators (2 or more required): ☐ Surface water (A1) ☐ Sparsely Vegetated Concave Surface (B8) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Drainage Patterns (B10) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Dry-Season Water Table (C2) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☒ Geomorphic Position (D2) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Shallow Aquitard (D3) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☒ FAC-Neutral Test (D5) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Frost-Heave Hummocks ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) Field Observations Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? (includes capillary fringe) Yes ☐ No ☒ Depth (in): Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Less than average rainfall. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version 750 Sixth Street South Kirkland, Washington 98033 (425) 822-5242 watershedco.com WETLAND DETERMINATION DATA FORM Western Mountains, Valleys, and Coast Supplement to the 1987 COE Wetlands Delineation Manual Project Site: Segment N, parcel number 2123059003 Sampling Date: 7/8/2015 Applicant/Owner: Puget Sound Energy Sampling Point: DP- 2 Investigator: Katy Crandall, Rose Whitson City/County: Renton Sect., Township, Range: S 16 T 23 R 05 State: WA Landform (hillslope, terrace, etc): Hillslope, hummocky Slope (%): 2 Local relief (concave, convex, none): Concave Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: AgC – Alderwood gravelly sandy loam, 8-15% slopes NWI classification: NA Are climatic/hydrologic conditions on the site typical for this time of year? ☐ Yes ☒ No (If no, explain in remarks.) Are “Normal Circumstances” present on the site? ☒ Yes ☐ No (If needed, explain any answers in Remarks.) Are Vegetation☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are Vegetation☐, Soil ☐, or Hydrology ☐ naturally problematic SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☐ No ☒ Is the Sampling Point within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☒ No ☐ Wetland Hydrology Present? Yes ☐ No ☒ Remarks: Out-pit near wetland NR01. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5m diam.) Absolute % Cover Dominant Species? Indicator Status Dominance Test Worksheet 1. Number of Dominant Species that are OBL, FACW, or FAC: 1 (A) 2. 3. Total Number of Dominant Species Across All Strata: 4 (B) 4. = Total Cover Percent of Dominant Species that are OBL, FACW, or FAC: 25 (A/B) Sapling/Shrub Stratum (Plot size: 3m diam.) 1. Spiraea douglasii 40 Y FACW Prevalence Index Worksheet 2. Total % Cover of Multiply by 3. OBL species x 1 = 4. FACW species x 2 = 5. FAC species x 3 = 40 = Total Cover FACU species x 4 = UPL species x 5 = Herb Stratum (Plot size: 1m diam.) Column totals (A) (B) 1. Gaultheria shallon 75 Y FACU 2. Pteridium aquilinum 15 Y FACU Prevalence Index = B / A = 3. 4. Hydrophytic Vegetation Indicators 5. ☐ Dominance test is > 50% 6. ☐ Prevalence test is ≤ 3.0 * 7. Morphological Adaptations * (provide supporting 8. ☐ data in remarks or on a separate sheet) 9. ☐ Wetland Non-Vascular Plants * 10. ☐ Problematic Hydrophytic Vegetation * (explain) 11. 90 = Total Cover * Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic Woody Vine Stratum (Plot size: ) Hydrophytic Vegetation Present? Yes ☐ No ☒ 1. Rubus armeniacus 20 Y FACU 2. = Total Cover % Bare Ground in Herb Stratum: Remarks: DP- 2 US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version SOIL Sampling Point – DP-2 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-6 10YR 2/2 100 Loam 6-12 7.5YR 4/2 80 5YR 4/6 20 C M Gravelly loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains 2Loc: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Other (explain in remarks) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ ☐ Depleted Below Dark Surface (A11) ☒ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☒ No ☐ Type: ________________________________________ Depth (inches): _____________________________________ Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply): Secondary Indicators (2 or more required): ☐ Surface water (A1) ☐ Sparsely Vegetated Concave Surface (B8) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Drainage Patterns (B10) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Dry-Season Water Table (C2) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☐ Geomorphic Position (D2) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Shallow Aquitard (D3) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☐ FAC-Neutral Test (D5) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Frost-Heave Hummocks ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) Field Observations Wetland Hydrology Present? Yes ☐ No ☒ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? (includes capillary fringe) Yes ☐ No ☒ Depth (in): Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Less than average rainfall. US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version 750 Sixth Street South Kirkland, Washington 98033 (425) 822-5242 watershedco.com WETLAND DETERMINATION DATA FORM Western Mountains, Valleys, and Coast Supplement to the 1987 COE Wetlands Delineation Manual Project Site: Segment M, parcel number 1623059059 Sampling Date: 5/22/2015 Applicant/Owner: Puget Sound Energy Sampling Point: DP- 3 Investigator: Katy Crandall, Mike Foster, Ryan Kahlo City/County: Renton Sect., Township, Range: S 16 T 23 R 05 State: WA Landform (hillslope, terrace, etc): Depression Slope (%): <5 Local relief (concave, convex, none): Concave Subregion (LRR): A Lat: Long: Datum: Soil Map Unit Name: An – Arents, Everett material NWI classification: PABFh Are climatic/hydrologic conditions on the site typical for this time of year? ☒ Yes ☐ No (If no, explain in remarks.) Are “Normal Circumstances” present on the site? ☒ Yes ☐ No (If needed, explain any answers in Remarks.) Are Vegetation☐, Soil ☐, or Hydrology ☐ significantly disturbed? Are Vegetation☐, Soil ☐, or Hydrology ☐ naturally problematic SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ☒ No ☐ Is the Sampling Point within a Wetland? Yes ☐ No ☒ Hydric Soils Present? Yes ☐ No ☒ Wetland Hydrology Present? Yes ☒ No ☐ Remarks: Low area on Segale property; area appears to have been disturbed in the past. Mix of wetland and non-wetland vegetation near DP. VEGETATION – Use scientific names of plants. Tree Stratum (Plot size: 5m diam.) Absolute % Cover Dominant Species? Indicator Status Dominance Test Worksheet 1. Number of Dominant Species that are OBL, FACW, or FAC: 3 (A) 2. 3. Total Number of Dominant Species Across All Strata: 3 (B) 4. = Total Cover Percent of Dominant Species that are OBL, FACW, or FAC: 100 (A/B) Sapling/Shrub Stratum (Plot size: 3m diam.) 1. Populus balsamifera 30 Y FAC Prevalence Index Worksheet 2. Salix lucida 20 Y FACW Total % Cover of Multiply by 3. OBL species x 1 = 4. FACW species x 2 = 5. FAC species x 3 = 50 = Total Cover FACU species x 4 = UPL species x 5 = Herb Stratum (Plot size: 1m diam.) Column totals (A) (B) 1. Juncus effusus 70 Y FACW 2. Achillea millefolium 10 N FACU Prevalence Index = B / A = 3. Phalaris arundinacea 5 N FACW 4. Cirsium arvense 5 N FAC Hydrophytic Vegetation Indicators 5. Carex stipata 3 N OBL ☐ Dominance test is > 50% 6. ☐ Prevalence test is ≤ 3.0 * 7. Morphological Adaptations * (provide supporting 8. ☐ data in remarks or on a separate sheet) 9. ☐ Wetland Non-Vascular Plants * 10. ☐ Problematic Hydrophytic Vegetation * (explain) 11. 93 = Total Cover * Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic Woody Vine Stratum (Plot size: ) Hydrophytic Vegetation Present? Yes ☒ No ☐ 1. 2. = Total Cover % Bare Ground in Herb Stratum: Remarks: DP- 3 US Army Corps of Engineers Western Mountains, Valleys, and Coast – Interim Version SOIL Sampling Point – DP-3 HYDROLOGY Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features (inches) Color (moist) % Color (moist) % Type1 Loc2 Texture Remarks 0-12 10YR 4/2 99 10YR 4/4 1 C M Gravelly sandy loam 1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains 2Loc: PL=Pore Lining, M=Matrix Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3 ☐ Histosol (A1) ☐ Sandy Redox (S5) ☐ 2cm Muck (A10) ☐ Histic Epipedon (A2) ☐ Stripped Matrix (S6) ☐ Red Parent Material (TF2) ☐ Black Histic (A3) ☐ Loamy Mucky Mineral (F1) (except MLRA 1) ☐ Other (explain in remarks) ☐ Hydrogen Sulfide (A4) ☐ Loamy Gleyed Matrix (F2) ☐ ☐ Depleted Below Dark Surface (A11) ☐ Depleted Matrix (F3) ☐ Thick Dark Surface (A12) ☐ Redox Dark Surface (F6) 3 Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic ☐ Sandy Mucky Mineral (S1) ☐ Depleted Dark Surface (F7) ☐ Sandy Gleyed Matrix (S4) ☐ Redox Depressions (F8) Restrictive Layer (if present): Hydric soil present? Yes ☐ No ☒ Type: ________________________________________ Depth (inches): _____________________________________ Remarks: Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply): Secondary Indicators (2 or more required): ☐ Surface water (A1) ☐ Sparsely Vegetated Concave Surface (B8) ☐ Water-Stained Leaves (B9) (MLRA 1, 2, 4A & 4B) ☐ High Water Table (A2) ☐ Water-Stained Leaves (except MLRA 1, 2, 4A & 4B) (B9) ☐ Drainage Patterns (B10) ☐ Saturation (A3) ☐ Salt Crust (B11) ☐ Dry-Season Water Table (C2) ☐ Water Marks (B1) ☐ Aquatic Invertebrates (B13) ☐ Saturation Visible on Aerial Imagery (C9) ☐ Sediment Deposits (B2) ☐ Hydrogen Sulfide Odor (C1) ☒ Geomorphic Position (D2) ☐ Drift Deposits (B3) ☐ Oxidized Rhizospheres along Living Roots (C3) ☐ Shallow Aquitard (D3) ☐ Algal Mat or Crust (B4) ☐ Presence of Reduced Iron (C4) ☒ FAC-Neutral Test (D5) ☐ Iron Deposits (B5) ☐ Recent Iron Reduction in Tilled Soils (C6) ☐ Raised Ant Mounds (D6) (LRR A) ☐ Surface Soil Cracks (B6) ☐ Stunted or Stressed Plants (D1) (LRR A) ☐ Frost-Heave Hummocks ☐ Inundation Visible on Aerial Imagery (B7) ☐ Other (explain in remarks) Field Observations Wetland Hydrology Present? Yes ☒ No ☐ Surface Water Present? Yes ☐ No ☒ Depth (in): Water Table Present? Yes ☐ No ☒ Depth (in): Saturation Present? (includes capillary fringe) Yes ☐ No ☒ Depth (in): Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: Damp low in soil profile; not saturated The Watershed Company May 2016 A PPENDIX C Wetland Rating Forms Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 1 RATING SUMMARY – Western Washington Name of wetland (or ID #): Wetland NR01 Date of site visit: 7/8/2014 Rated by: Trained by Ecology? ☒Y ☐N Date of training: 09/2014 HGM Class used for rating: Slope Wetland has multiple HGM classes? ☐Y ☒N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map: City of Renton online mapping application (COR Maps) OVERALL WETLAND CATEGORY (based on functions ☒ or special characteristics ☐) 1. Category of wetland based on FUNCTIONS ☐ Category I – Total score = 23 - 27 ☐ Category II – Total score = 20 - 22 ☒ Category III – Total score = 16 - 19 ☐ Category IV – Total score = 9 - 15 FUNCTION Improving Water Quality Hydrologic Habitat Circle the appropriate ratings Site Potential H M L H M L H M L Landscape Potential H M L H M L H M L Value H M L H M L H M L TOTAL Score Based on Ratings 5 6 7 18 2. Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above ☒ Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H,H,M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L,L,L Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 2 Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 Hydroperiods D 1.4, H 1.2 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 Boundary of area within 150 ft of the wetland (can be added to another figure) D 2.2, D 5.2 Map of the contributing basin D 4.3, D 5.3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 Riverine Wetlands Map of: To answer questions: Figure # Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Ponded depressions R 1.1 Boundary of area within 150 ft of the wetland (can be added to another figure) R 2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R 4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R 3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Fringe Wetlands Map of: To answer questions: Figure # Cowardin plant classes L 1.1, L 4.1, H 1.1, H 1.4 Plant cover of trees, shrubs, and herbaceous plants L 1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L 2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L 3.3 Slope Wetlands Map of: To answer questions: Figure # Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Plant cover of dense trees, shrubs, and herbaceous plants S 1.3 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (can be added to figure above) S 4.1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S 3.3 Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 3 HGM Classification of Wetlands in Western Washington 1. Are the water levels in the entire unit usually controlled by tides except during floods? ☒NO – go to 2 ☐YES – the wetland class is Tidal Fringe – go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO – Saltwater Tidal Fringe (Estuarine) YES – Freshwater Tidal Fringe If your wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. ☒NO – go to 3 ☐YES – The wetland class is Flats If your wetland can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? ☐The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; ☐At least 30% of the open water area is deeper than 6.6 ft (2 m). ☒NO – go to 4 ☐YES – The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? ☒The wetland is on a slope (slope can be very gradual), ☒The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, ☒The water leaves the wetland without being impounded. ☐NO – go to 5 ☒YES – The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? ☐The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, ☐The overbank flooding occurs at least once every 2 years. For questions 1-7, the criteria described must apply to the entire unit being rated. If the hydrologic criteria listed in each question do not apply to the entire unit being rated, you probably have a unit with multiple HGM classes. In this case, identify which hydrologic criteria in questions 1-7 apply, and go to Question 8. Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 4 ☐NO – go to 6 ☐YES – The wetland class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year? This means that any outlet, if present, is higher than the interior of the wetland. ☐NO – go to 7 ☐YES – The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ☐NO – go to 8 ☐YES – The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE If you are still unable to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 11 SLOPE WETLANDS Water Quality Functions - Indicators that the site functions to improve water quality S 1.0. Does the site have the potential to improve water quality? S 1.1. Characteristics of the average slope of the wetland: (a 1% slope has a 1 ft vertical drop in elevation for every 100 ft of horizontal distance) Slope is 1% or less points = 3 Slope is > 1%-2% points = 2 Slope is > 2%-5% points = 1 Slope is greater than 5% points = 0 1 S 1.2. The soil 2 in below the surface (or duff layer) is true clay or true organic (use NRCS definitions): Yes = 3 No = 0 0 S 1.3. Characteristics of the plants in the wetland that trap sediments and pollutants: Choose the points appropriate for the description that best fits the plants in the wetland. Dense means you have trouble seeing the soil surface (>75% cover), and uncut means not grazed or mowed and plants are higher than 6 in. Dense, uncut, herbaceous plants > 90% of the wetland area points = 6 Dense, uncut, herbaceous plants > ½ of area points = 3 Dense, woody, plants > ½ of area points = 2 Dense, uncut, herbaceous plants > ¼ of area points = 1 Does not meet any of the criteria above for plants points = 0 6 Total for S 1 Add the points in the boxes above 7 Rating of Site Potential If score is: ☐12 = H ☒6-11 = M ☐0-5 = L Record the rating on the first page S 2.0. Does the landscape have the potential to support the water quality function of the site? S 2.1. Is > 10% of the area within 150 ft on the uphill side of the wetland in land uses that generate pollutants? Yes = 1 No = 0 0 S 2.2. Are there other sources of pollutants coming into the wetland that are not listed in question S 2.1? Other sources Yes = 1 No = 0 0 Total for S 2 Add the points in the boxes above 0 Rating of Landscape Potential If score is: ☐1-2 = M ☒0 = L Record the rating on the first page S 3.0. Is the water quality improvement provided by the site valuable to society? S 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on the 303(d) list? Yes = 1 No = 0 0 S 3.2. Is the wetland in a basin or sub-basin where water quality is an issue? At least one aquatic resource in the basin is on the 303(d) list. Yes = 1 No = 0 1 S 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality? Answer YES if there is a TMDL for the basin in which unit is found. Yes = 2 No = 0 0 Total for S 3 Add the points in the boxes above 1 Rating of Value If score is: ☐2-4 = H ☒1 = M ☐0 = L Record the rating on the first page Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 12 SLOPE WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream erosion S 4.0. Does the site have the potential to reduce flooding and stream erosion? S 4.1. Characteristics of plants that reduce the velocity of surface flows during storms: Choose the points appropriate for the description that best fits conditions in the wetland. Stems of plants should be thick enough (usually >1/8 8 in), or dense enough, to remain erect during surface flows. Dense, uncut, rigid plants cover > 90% of the area of the wetland points = 1 All other conditions points = 0 1 Rating of Site Potential If score is: ☒1 = M ☐0 = L Record the rating on the first page S 5.0. Does the landscape have the potential to support the hydrologic functions of the site? S 5.1. Is more than 25% of the area within 150 ft upslope of wetland in land uses or cover that generate excess surface runoff? Yes = 1 No = 0 0 Rating of Landscape Potential If score is: ☐1 = M ☒0 = L Record the rating on the first page S 6.0. Are the hydrologic functions provided by the site valuable to society? S 6.1. Distance to the nearest areas downstream that have flooding problems: The sub-basin immediately down-gradient of site has flooding problems that result in damage to human or natural resources (e.g., houses or salmon redds) points = 2 Surface flooding problems are in a sub-basin farther down-gradient points = 1 No flooding problems anywhere downstream points = 0 2 S 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? Yes = 2 No = 0 0 Total for S 6 Add the points in the boxes above 2 Rating of Value If score is: ☒2-4 = H ☐1 = M ☐0 = L Record the rating on the first page NOTES and FIELD OBSERVATIONS: Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 13 These questions apply to wetlands of all HGM classes. HABITAT FUNCTIONS - Indicators that site functions to provide important habitat H 1.0. Does the site have the potential to provide habitat? H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of ¼ ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. ☐ Aquatic bed 4 structures or more: points = 4 ☒ Emergent 3 structures: points = 2 ☒ Scrub-shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 ☐ Forested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if: ☐ The Forested class has 3 out of 5 strata (canopy, sub-canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon 1 H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or ¼ ac to count (see text for descriptions of hydroperiods). ☐ Permanently flooded or inundated 4 or more types present: points = 3 ☐ Seasonally flooded or inundated 3 types present: points = 2 ☒ Occasionally flooded or inundated 2 types present: points = 1 ☒ Saturated only 1 type present: points = 0 ☐ Permanently flowing stream or river in, or adjacent to, the wetland ☐ Seasonally flowing stream in, or adjacent to, the wetland ☐ Lake Fringe wetland 2 points ☐ Freshwater tidal wetland 2 points 1 H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ft2. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species points = 2 5 - 19 species points = 1 < 5 species points = 0 1 H 1.4. Interspersion of habitats Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. None = 0 points Low = 1 point Moderate = 2 points All three diagrams in this row are HIGH = 3points 1 Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 14 H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. ☐ Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). ☐ Standing snags (dbh > 4 in) within the wetland ☐ Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) ☐ Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed) ☐ At least ¼ ac of thin-stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg-laying by amphibians) ☐ Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata) 0 Total for H 1 Add the points in the boxes above 4 Rating of Site Potential If score is: ☐15-18 = H ☐7-14 = M ☒0-6 = L Record the rating on the first page H 2.0. Does the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat: 0 + [(40% moderate and low intensity land uses)/2]: 20 = 20% If total accessible habitat is: > 1/3 (33.3%) of 1 km Polygon points = 3 20-33% of 1 km Polygon points = 2 10-19% of 1 km Polygon points = 1 < 10% of 1 km Polygon points = 0 2 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat: 20 + [(50% moderate and low intensity land uses)/2]: 25 = 45% Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in 1-3 patches points = 2 Undisturbed habitat 10-50% and > 3 patches points = 1 Undisturbed habitat < 10% of 1 km Polygon points = 0 2 H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use points = (- 2) ≤ 50% of 1 km Polygon is high intensity points = 0 0 Total for H 2 Add the points in the boxes above 4 Rating of Landscape Potential If score is: ☒4-6 = H ☐1-3 = M ☐< 1 = L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 ☒ It has 3 or more priority habitats within 100 m (see next page) ☐ It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) ☐ It is mapped as a location for an individual WDFW priority species ☐ It is a Wetland of High Conservation Value as determined by the Department of Natural Resources ☐ It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 Site does not meet any of the criteria above points = 0 2 Rating of Value If score is: ☒2 = H ☐1 = M ☐0 = L Record the rating on the first page Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 15 WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. http://wdfw.wa.gov/publications/00165/wdfw00165.pdf or access the list from here: http://wdfw.wa.gov/conservation/phs/list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. ☐ Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). ☒ Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). ☐ Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. ☐ Old-growth/Mature forests: Old-growth west of Cascade crest – Stands of at least 2 tree species, forming a multi- layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests – Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth; 80-200 years old west of the Cascade crest. ☐ Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 – see web link above). ☒ Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. ☐ Westside Prairies: Herbaceous, non-forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 – see web link above). ☒ Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. ☐ Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report – see web link on previous page). ☐ Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. ☐ Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. ☐ Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. ☒ Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 16 CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Check off any criteria that apply to the wetland. Circle the category when the appropriate criteria are met. Category SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? ☐ The dominant water regime is tidal, ☐ Vegetated, and ☐ With a salinity greater than 0.5 ppt ☐Yes –Go to SC 1.1 ☒No= Not an estuarine wetland SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? ☐Yes = Category I ☐No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland has at least two of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. ☐Yes = Category I ☐No= Category II Cat. I Cat. II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? ☐Yes – Go to SC 2.2 ☒No – Go to SC 2.3 SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? ☐Yes = Category I ☐No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? http://www1.dnr.wa.gov/nhp/refdesk/datasearch/wnhpwetlands.pdf ☐Yes – Contact WNHP/WDNR and go to SC 2.4 ☒No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? ☐Yes = Category I ☐No = Not a WHCV Cat. I SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 in or more of the first 32 in of the soil profile? ☐Yes – Go to SC 3.3 ☒No – Go to SC 3.2 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less than 16 in deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a lake or pond? ☐Yes – Go to SC 3.3 ☒No = Is not a bog SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND at least a 30% cover of plant species listed in Table 4? ☐Yes = Is a Category I bog ☐No – Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? ☐Yes = Is a Category I bog ☐No = Is not a bog Cat. I Wetland name or number: NR01 Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 17 SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife’s forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. ☐ Old-growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi-layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. ☐ Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm). ☐Yes = Category I ☒No = Not a forested wetland for this section Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? ☐ The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks ☐ The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) ☐Yes – Go to SC 5.1 ☒No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? ☐ The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). ☐ At least ¾ of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. ☐ The wetland is larger than 1/10 ac (4350 ft2) ☐Yes = Category I ☐No = Category II Cat. I Cat. II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: ☐ Long Beach Peninsula: Lands west of SR 103 ☐ Grayland-Westport: Lands west of SR 105 ☐ Ocean Shores-Copalis: Lands west of SR 115 and SR 109 ☐Yes – Go to SC 6.1 ☒No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M for the three aspects of function)? ☐Yes = Category I ☐No – Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? ☐Yes = Category II ☐No – Go to SC 6.3 SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? ☐Yes = Category III ☐No = Category IV Cat I Cat. II Cat. III Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter “Not Applicable” on Summary Form NA Wetland Rating System for Western WA: 2014 Update Rating Form – Effective January 1, 2015 18 Wetland name or number This page left blank intentionally W ETLAND NR01 2014 WETLAND RATING FORM FIGURES Figure 1. Map of Cowardin plant classes with 150-foot buffer for Wetland NR01. ........... 2 Figure 2. Map of hydroperiods for Wetland NR01. .......................................................... 3 Figure 3. Approximate 1 km polygon that extends from Wetland NR01 edge including polygons for undisturbed and moderate intensity land use. ...................... 4 Figure 4. Screen capture of map of 303d listed waters in basin (from Ecology web site). 5 Figure 5. Screen capture of list of TMDL’s for WRIA in which wetland unit is found (from web). ........................................................................................................ 6 2 Figure 1. Map of Cowardin plant classes with 150-foot buffer for Wetland NR01. S4.1 – Scrub-shrub and emergent Cowardin classes are considered both dense and rigid. Emergent Scrub-shrub 3 Figure 2. Map of hydroperiods for Wetland NR01. Saturated only Occasionally flooded 4 Figure 3. Approximate 1 km polygon that extends from Wetland NR01 edge including polygons for undisturbed and moderate intensity land use. 1 km polygon Moderate intensity (orange) Undisturbed (purple) High Intensity 5 Figure 4. Screen capture of map of 303d listed waters in basin (from Ecology web site). Approximate location of wetland 6 Figure 5. Screen capture of list of TMDL’s for WRIA in which wetland unit is found (from web). A P P E N D I X C 2017 Delineation Study Update November 29, 2017 Kelly Purnell Project Manager PSE Energize Eastside 355 110th Avenue NE Bellevue, WA 98004 Via email: Kelly.Purnell@pse.com Re: PSE Energize Eastside Project – 2017 Additional Wetland and Stream Delineation in Renton The Watershed Company Reference Number: 111103.8 Dear Kelly: This letter presents the findings of an additional wetland and stream delineation study in the vicinity of the Energize Eastside Project (the Project) in Renton. Original wetland and stream delineation field work for the Project in Renton occurred in 2015 and is documented in the City of Renton Critical Areas Delineation Report: Puget Sound Energy – Energize Eastside Project (The Watershed Company 2016; hereafter “Renton Delineation Report”). Project design changes warranted additional wetland and stream delineation inventory and assessment. This letter documents the findings of the latest delineation effort in Renton; it is intended to be included as an appendix to the City of Renton Critical Areas Report: Puget Sound Energy – Energize Eastside Project (The Watershed Company 2017; hereafter “Renton CAR”). The following documents are enclosed: Wetland Determination Data Forms 2014 Ecology Wetland Rating Forms and Figures for wetlands outside of shoreline jurisdiction 2004 Ecology Wetland Rating Forms for wetlands in shoreline jurisdiction 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 2 Study Area The study area for the original 2015 delineation field work was an approximate 100-foot wide corridor based on the location of two existing transmission lines which were typically spaced approximately 50 feet apart. If the field, study area boundaries were determined by measuring 25 feet out from the center of each pole set. The approximate study area is depicted in Appendix A (Critical Area Delineation Maps) of the Renton Delineation Report. The length of the corridor was approximately 3.7 miles in Renton, but specifically excluded the lower portion of the Cedar River ravine, described as follows: on the south side of the ravine, survey limits included the area approximately 425 feet north-northwest beyond the existing structure(s); and on the north side of the ravine, survey limits included the area approximately 250 feet south-southeast beyond the existing structure(s). As the Project design has become more refined, the need for additional delineation was identified in the vicinity of the Cedar River (previously excluded) and south of the original study area corridor between the Talbot Hill substation and Shadow Hawk neighborhood. These areas are depicted approximately in Figure 1 below. The portion of a wetland boundary adjacent to the original study area corridor was also captured during this additional field work, located at the base of the slope between the Cedar River Trail and Shadow Hawk neighborhood (Figure 1). 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 3 Figure 1. Approximate locations of additional wetland and stream delineation study areas (orange). Methods Public-domain information on the study area was reviewed for this delineation study and include the following: USDA Natural Resources Conservation Service, Web Soil Survey (WSS) application U.S. Fish and Wildlife Service National Wetland Inventory (NWI) maps Washington Department of Fish and Wildlife interactive mapping programs (PHS on the Web and SalmonScape) 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 4 Washington Department of Natural Resources, Forest Practices Application Mapping Tool (FPARS) Washington Department of Natural Resources, Wetlands of High Conservation Value Map Viewer King County’s GIS mapping website (iMap) City of Renton (COR) maps Characterization of climatic conditions for precipitation was determined using the WETS table methodology from the USDA NRCS document Part 650 Engineering Field Handbook, National Engineering Handbook, Hydrology Tools for Wetland Identification and Analysis, Chapter 19 (September 2015). The Seattle-Tacoma International AP station as recorded by NOAA (http://agacis.rcc-acis.org/) was used as a source for precipitation data. The WETS table methodology uses climate data from the three months prior to the site visit month to determine if normal conditions are present. Wetlands The study area was evaluated for wetlands using methodology from the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region Version 2.0 (Regional Supplement) (US Army Corps of Engineers [Corps] May 2010). Wetland boundaries were determined on the basis of an examination of vegetation, soils, and hydrology. Areas meeting the criteria set forth in the Regional Supplement were determined to be wetland. Soil, vegetation, and hydrologic parameters were sampled at several locations along the wetland boundary to make the determination. Identified wetlands within the study area were classified using the 2014 Update to the Western Washington Wetland Rating System (Hruby 2014; hereafter “2014 Rating System”), in accordance with Renton’s critical area regulations. If wetlands in the study area were located in shoreline jurisdiction, they were rated using the Washington State Wetland Rating System for Western Washington, Version 2 (Hruby 2004; hereafter “2004 Rating System”), in accordance with Renton’s Shoreline Management Program (SMP). Streams The study area was evaluated for streams based on the presence or absence of an ordinary high water mark (OHWM) as defined by the Revised Code of Washington (RCW) 90.58.030 and the Washington Administrative Code (WAC) 220-660-030. The OHWM edge was located by examining the bed and bank physical characteristics and vegetation. Streams were classified according to applicable Renton regulations. 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 5 GPS Location Wetland boundaries, stream OHWM edges or centerlines, data points, and other features were GPS-located using a hand-held Trimble Geo-XH unit. Following field location, the GPS data were differentially corrected using GPS Pathfinder Office and exported into ESRI ArcGIS software for mapping. Findings Wetlands Four wetlands were entirely or partially delineated during this recent field work effort. Two additional wetlands were identified, but not delineated. These six features are described below. Wetland NR02 Wetland NR02 is a depressional wetland located south of the Cedar River crossing. Vegetation is dominated by palustrine scrub-shrub and palustrine forested vegetation classes. A large portion of this wetland in permanently ponded. The pond appears to have been created from beaver activity in 2011-2012 based on Google Earth aerial images. The ponded area has transitioned from palustrine forested/scrub-shrub vegetation to palustrine aquatic bed and open water. As a result, standing snags and downed woody debris are abundant in the permanently ponded area. Common plants observed include red alder, black cottonwood, salmonberry, redtwig dogwood, skunk cabbage and lady fern. Sampled wetland soils (DP-5) were a silty loam and met the criteria for hydric soil indicator Hydrogen Sulfide (A4). Hydrogen Sulfide Odor (C1) was also the primary hydrology indicator observed. In addition, soils were nearly saturated and met two secondary hydrology indicators. Wetland NR02 is primarily supported by groundwater seeps and groundwater supplied by a culvert at the eastern end of the wetland that conveys water from Wetland NR03, south of the Cedar River Trail. Hydrology is also affected by the historic beaver activity in the area. Wetland NR03 Wetland NR03 is a depressional wetland located southeast of Wetland NR02, on the opposite side of the Cedar River Trail. The majority of the wetland is permanently ponded. Vegetation is dominated by palustrine scrub-shrub and palustrine aquatic bed vegetation classes with a considerable amount of dead wood also present. Common plants observed include willows, salmonberry, redtwig dogwood, Himalayan blackberry, bittersweet nightshade, soft rush, and duckweed. Sampled wetland soils (DP-6) were a loam/clay loam and met the criteria for hydric soil indicator Hydrogen Sulfide (A4) and Redox Dark Surface (F6). Primary hydrology indicators observed at the test pit include Saturation (A3), Hydrogen Sulfide Odor (C1), and Oxidized Rhizospheres along Living Roots (C3). Wetland NR03 is primarily supported by a high 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 6 groundwater table. A culvert under the trail conveys water to Wetland NR02 to the northwest. Wetland NR04 Wetland NR04 is a slope wetland located west of the Shadow Hawk Condominiums. Vegetation is dominated by a palustrine emergent vegetation class. Common plants observed include reed canarygrass, stinging nettle, Himalayan blackberry, lady fern, and salmonberry. Sampled wetland soils (DP-8) were a clay loam and met the criteria for hydric soil indicator Redox Dark Surface (F6). Primary hydrology indicators were not observed at the test pit, but conditions at the data point met the criteria for two secondary hydrology indicators. Wetland NR04 is primarily supported by groundwater seeps and supplemented by surface water and precipitation. Wetland NR05 Wetland NR05 is a depressional wetland located east of SE Cedar Ridge Drive near the southern end of the study area. Vegetation is classified as palustrine forested, palustrine scrub-shrub and palustrine emergent. Common plants observed include red alder, Oregon ash, salmonberry, cattail, lady fern, giant horsetail, soft rush, and small-fruited bulrush. Sampled wetland soils (DP-10 and DP-12) were a gravelly clay loam and met the criteria for hydric soil indicator Redox Dark Surface (F6). Soils in the wetland were saturated and conditions at the data point met the criteria for two secondary hydrology indicators. Wetland NR05 is primarily supported by groundwater seeps and supplemented by surface water and precipitation. Cedar North Wetland (not delineated) The Cedar North Wetland is a slope wetland located at a break in the steep slope north of the Maple Valley Highway/State-Route (SR)-169. Soil saturation, surface water seeps, and obligate plants were observed in this wetland. The approximate size and location of this wetland has been drawn based on field observations, aerial images, and topography. The Cedar North Wetland is presumably located in shoreline jurisdiction based on the approximate wetland boundary. Talbot Wetland (not delineated) The Talbot Wetland is a small, depressional wetland located north of the Talbot Hill substation. Vegetation is dominated by facultative and facultative wetland plants, soils meet at least one hydric soil indicator, and two secondary hydrology indicators were observed during the site visit. The approximate size and location of this wetland has been depicted based on field observations, aerial images, and topography. 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 7 Streams No new streams were identified in the study area during recent field work activities. However, the extent or OHWM location of two streams previously discussed in the delineation report were expanded/collected. In the Renton Delineation Report, the Cedar River was discussed and depicted, but had not been delineated. During recent field work activities, the OHWM of the left bank of the Cedar River was delineated; the right bank of the Cedar River in the study area was not easily accessible and located at the edge of a large concrete retaining wall supporting the Maple Valley Highway/SR-169 and was not delineated. For the right bank of the Cedar River, the OHWM is presumed to be consistent with the mapped Cedar River floodway. By comparison, on the left bank, the floodway is more encumbering than the delineated OHWM edge. The extent of Stream NR02 was expanded downstream near the Cedar River, beginning at a culvert outlet under the Cedar River Trail, to where it meets Wetland NR02 and flows west outside of the study area. Stream NR02 originates at the north end of Wetland NR04 and flows north parallel to the study area, before entering the study area again (as previously described) near the Cedar River Trail. Regulatory Implications Critical areas in the City of Renton are regulated in the Renton Municipal Code (RMC), Title IV Development Regulations, Chapter 3 Environmental Regulations and Overlay District, 4-3-050 Critical Areas Regulations. Shorelines, and wetlands located in shoreline jurisdiction, are regulated under the Renton Shoreline Master Program (RMC 4-3-090). According to RMC 4-3-050-G.9, wetlands located outside of shoreline jurisdiction are classified based on the 2014 Rating System. Wetland buffers are measured from the wetland edge and are based upon the wetland rating, associated habitat score, and impact of land use. The adjacent land use would not be considered low intensity, therefore the buffer width for “all other land uses” applies. Table 1 shows the ratings for wetlands that are not located in shoreline jurisdiction and the associated standard buffer widths. Wetland NR02 and (presumably) Cedar North Wetland are located within shoreline jurisdiction and therefore the regulations in RMC 4-3-090 apply. Wetlands in shoreline jurisdiction are rated using the 2004 version of the Ecology rating system. Wetland buffer widths are determined based upon the wetland rating and associated habitat score. Wetland NR02 is a Category II wetland with a high habitat score and requires a standard buffer width of 225 feet (Table 2). 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 8 Classifications and buffer widths for wetlands that were not formally delineated or rated (Cedar North and Talbot Wetlands) have been estimated in Tables 1 and 2, below. Estimated buffer widths were used to determine if Project activities are likely or unlikely to affect these critical areas. Table 1. Wetland ratings and associated buffer widths for wetlands located outside of shoreline jurisdiction. Wetland Name 2014 Rating System Category Standard Buffer Width (feet) Water Quality Hydrology Habitat Total NR03 6 5 7 18 III 100 NR04 5 5 6 16 III 100 NR05 5 6 7 18 III 100 Talbot* -- -- -- -- ~III ~100 * Wetland not delineated or formally rated; rating is estimated and a moderate habitat score is presumed to determine approximate buffer width. Table 2. Wetland rating and associated buffer width for Wetland NR02 located in shoreline jurisdiction. Wetland Name 2004 Rating System Category Standard Buffer Width (feet) Water Quality Hydrology Habitat Total NR02 12 12 29 53 II 225 Cedar North* -- -- -- -- ~III ~125 * Wetland not delineated or formally rated; rating is estimated and a moderate habitat score is presumed to determine approximate buffer width. The additional delineation of streams in the study area do not change the regulatory implications described in the Renton Delineation Report. Therefore, they are not discussed further here. Disclaimer The information contained in this letter is based on the application of technical guidelines currently accepted as the best available science and in conjunction with the manuals and criteria outlined in the methods section. All discussions, conclusions and recommendations reflect the best professional judgment of the author(s) and are based upon information available at the time the study was conducted. All work was completed within the constraints of budget, scope, and timing. The findings of this 2017 Renton Wetland and Stream Delineation Study PSE, Kelly Purnell December 2017 Page 9 report are subject to verification and agreement by the appropriate local, state and federal regulatory authorities. No other warranty, expressed or implied, is made. Please call if you have any questions or if we can provide you with any additional information. Sincerely, Katy Crandall, WPIT Ecologist / Arborist Enclosures A PPE N D I X D Detailed CAIA Methodology A PPENDIX D Detailed CAIA Methodology This detailed Critical Area Impact Analysis (CAIA) is intended to further describe the methods used to generate critical area features and existing land cover classes used in conjunction with PSE site plans in order to quantify impacts resulting from implementation of the Energize Eastside Project (“the Project”). This Appendix is meant to complement and expand upon the methods described in the body of the Critical Area Report. Methodology Outline: Critical Area Delineation and Mapping Methods - Wetlands - Streams - Functioning Wetland and Stream Buffers - Geologic Hazard Areas - Shoreline Jurisdiction Existing Land Cover Mapping - Vegetation Assessment Methods Impact Characterization - Energize Eastside 230K Line - Lake Tradition 115K Line Critical Areas Impact Assessment Quality Assurance Review of Analysis Steps and Results Limitations Data Sources Table The Watershed Company January 2018 II Critical Area Delineation and Mapping Methods Wetland and stream critical areas were delineated and classified by The Watershed Company between March and October 2015 coincident with the field work for vegetation inventory analysis. These delineated features were GPS‐ located. Responding to the design alignment provided by PSE in November and December 2017, supplemental reconnaissance and vegetation inventory was conducted to ensure coverage of the full project corridor. Critical area features not delineated in the field were mapped using publicly‐ available contour and aerial GIS data, which was then refined according to observations of the ecologists who conducted the field reconnaissance. A table provided at the end of this document lists data sources for each mapped critical area. Wetland Delineation The study area was evaluated for wetlands using methodology from the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region Version 2.0 (Regional Supplement) (US Army Corps of Engineers [Corps] May 2010). Wetland boundaries were determined on the basis of an examination of vegetation, soils, and hydrology. Areas meeting the criteria set forth in the Regional Supplement were determined to be wetland. Soil, vegetation, and hydrologic parameters were sampled at several locations along the wetland boundary to make the determination. Identified wetlands outside of shoreline jurisdiction have been classified using the 2014 Update to the Western Washington Wetland Rating System (Ecology publication #14‐06‐029) per Renton regulations. Wetlands within shoreline jurisdiction have been classified using the 2004 Ecology rating system per Renton Municipal Code (RMC) 4‐3‐090.D.2.d.ii. Stream Delineation The study area was also evaluated for streams based on the presence or absence of an ordinary high water mark (OHWM) as defined by the Revised Code of Washington (RCW) 90.58.030 and the Washington Administrative Code (WAC) 220‐660‐030. The OHWM edge was located by examining the bed and bank physical characteristics and vegetation. The centerlines of streams in the study area were recorded in the field, with stream widths approximated in the field and based on aerial photometry and elevation contours. Streams were classified according to the RMC. The Watershed Company January 2018 III Functioning Wetland and Stream Buffers Mapping Standard buffers were applied to delineated wetland and stream edges in GIS according to regulatory buffer widths in RMC Section 4‐3‐050 (Critical Areas Regulations). In some cases, developed areas intruded into these mapped standard buffers. To remove these non‐functioning buffer areas from the assessment of Project impacts, developed areas (see land cover mapping section) were manually removed from the standard buffer polygons in GIS (based on observed field conditions and recent aerial photography). The resulting functioning buffers were used to determine buffer impacts and mitigation needs. Geologic Hazard Areas and Buffers Mapping Five regulated geologic hazard area types occur within the Project corridor in Renton including erosion hazards areas, landslide hazards areas, seismic hazard areas, coal mine hazard areas, and steep slopes. According to RMC 4‐3‐050(G)(2), and the GeoEngineers Report (Appendix C), landslide hazard areas categorized as “very high” require a 50‐foot buffer and 15‐foot setback from the top, toe, and sides of the slope, while no buffer is applied to any other type of geologic hazard area. No very high landslide hazard areas are mapped within the Project area. Geospatial inventories of erosion, coal mine, seismic, and landslide hazards areas that are published by City of Renton GIS were used for this effort. The datasets were then clipped to the 500‐foot study corridor. Steep slopes in Renton are categorized and regulated as either “sensitive” or “protected” depending on grade and vertical rise. However, steep slope data provided by the City do not provide category information for the mapped features. In order to supplement the City’s inventory with this information, The Watershed Company generated steep slope hazard area data using high‐ resolution LIDAR data provided by PSE that represents the bare earth topographic surface for the greater study area. Topographic surface data were analyzed to identify and isolate areas where the slope of the ground surface is 40 percent or steeper. Features were then reanalyzed to identify and isolate slopes with an elevation change of at least 15 feet of vertical relief. These features were assigned the category of “protected,” while the remaining features were assigned the category of “sensitive.” The dataset was then clipped to the 500‐foot study corridor. Shoreline Jurisdiction Within the Project area, the Cedar River is designated as a Shoreline of the State and therefore subject to the City’s Shoreline Master Program (RMC 4‐3‐090). Shoreline jurisdiction is defined in RMC 4‐3‐090(B)(3) to include: a) lands within 200 feet from the OHWM, or lands within 200 feet from floodways, whichever is greater; b) contiguous floodplain areas; and c) all marshes, bogs, swamps, and The Watershed Company January 2018 IV river deltas associated with streams, lakes, and tidal waters that are subject to the provisions of the State Shoreline Management Act (SMA). A combination of field data and GIS inventories were used to map Cedar River shoreline jurisdiction. Floodway and floodplain areas were provided by City of Renton GIS. Within the Project area, no floodplain extends outside of the mapped floodway. The mapped floodway overlaps with the delineated OHWM on the north bank of the river and extends slightly beyond it on the south bank. As a result, a buffer of 200 feet was applied to the Cedar River floodway to form the basis for shoreline jurisdiction. On the south bank of the river, a delineated wetland falls within that 200‐foot buffer and extends outside of the 200‐foot buffer to the south. Consistent with the SMA and RMC, this wetland was considered “associated” with the Cedar River, and shoreline jurisdiction was extended to encompass its entire delineated boundary. A potential wetland was also identified within 200 feet of the OHWM on the northern bank of the Cedar River, which likely extends outside of the 200‐foot buffer to the north. However, this feature was not delineated. Therefore, the extent of shoreline jurisdiction on the north side of the Cedar River is approximated, conservatively, to encompass the approximated area of this wetland. Other critical areas mapped and analyzed include: Priority Habitat Protection Areas, Floodway, Floodplain, and Wellhead Protection Areas. These layers were downloaded from various sources and can be found in the Data Sources table at the end of this document. Existing Land Cover Mapping In order to quantify land cover changes from Project‐related activities, a layer showing existing land use was created to describe the current land cover conditions. The land cover base map was developed from the following existing data sources: • 2009 Impervious and Impacted Surface raster data set, King County GIS • Energize Eastside Corridor digital survey, APS Surveying, received May 2016 • Energize Eastside Corridor Tree Inventory data, The Watershed Company, compiled 2015‐2017 • Energize Eastside Corridor Vegetation Polygon data, The Watershed Company, compiled 2015‐2017 • Energize Eastside Corridor Wetland and Stream Inventory, The Watershed Company, compiled 2015‐2017 • High‐resolution aerial photography, PSE, captured in 2011 • 2015‐2016 aerial photography, King County GIS The Watershed Company January 2018 V Using the King County impervious surface raster, GIS analysts supplemented the mapped features using digital survey data. These data were further refined by manually reviewing mapped features against high‐resolution aerial photography and field‐verified conditions. After developed and non‐developed areas were mapped, vegetation and tree canopy coverage information were integrated (described in following subsection), as well as mapped open water areas (streams). This effort yielded a base map with six general land cover types: • Forested with understory vegetation • Forested without understory vegetation • Understory vegetation, unforested • Other (generally lawn) • Developed • Water Vegetation Assessment Methods A full description of the vegetation analysis methods, the results of which have been incorporated into the CAIA, is presented in the City of Renton Tree Inventory Report: Puget Sound Energy – Energize Eastside Project (The Watershed Company 2016b). The ways in which the results were used to generate the mapped features presented in the CAIA are summarized below. The Watershed Company certified arborists conducted a field‐based vegetation inventory from March 23, 2015, to November 9, 2015 associated with potential routes for the Energize Eastside Project. The methodology utilized during the inventory was developed to comprehensively identify, describe, and mark all vegetation greater than 15 feet tall, or that had the potential to reach a mature height of 15 feet or taller. Supplemental inventory was conducted using the same methodology in November and December 2017. Inventoried vegetation was mapped as points and/or polygons. Any tree with a diameter of six inches at four‐and‐a‐half feet above the ground surface (DBH) was mapped as a point and tagged with a unique number and its attributes were recorded. Landscaped vegetation with the potential to reach 15 feet or greater was also inventoried in this manner regardless of size. Finally, weedy vegetation (i.e., from seed [not planted] and not maintained) with a DBH of three to six inches was also inventoried in this way. This type of inventoried vegetation was typically survey‐located. In some instances, The Watershed Company certified arborists could not access or did not inventory vegetation that was previously or subsequently picked up by survey crews. This limitation was caused by a number of reasons that include a change in property access permissions; survey crew assessment limits as compared to the tree inventory study area; and/or the species, size, or condition The Watershed Company January 2018 VI of the tree or large shrub in question. Vegetation that was survey‐located but not inventoried by arborists has been incorporated into the CAIA analysis with an assumed maximum potential height of 25 feet and radius of 9 feet, as a rule. This assumption was based on the typical characteristic observed over majority of the project corridor. However, other attribute data associated with the survey‐ located only vegetation, such as species and condition, was not collected and no assumption was applied. A similar rule was applied in the area south of the Cedar River where trees were surveyed, but not inventoried by The Watershed Company crews. Based on the tree characteristics and species composition observed in this area, it was determined that the previously stated assumption of 25 feet for maximum potential height would be a significant underestimation. Lacking an arborist’s identification of tree species that could be used to assign maximum potential height, a proxy was used in the form of the surveyors’ notes. In order to approach a more accurate assumption for maximum potential height that could help determine potential tree impacts in this area, maximum vegetation height was based on the “best guess” tree species notes from the surveyors. The canopy radius was presumed to be 9 feet. Under the standard vegetation control parameters, some trees within the shoreline jurisdiction of the Cedar River would be removed. However, as communicated by PSE, no trees within shoreline jurisdiction will be removed by this Project. Where eventual conflicts between wire elevation and maximum potential tree height are predicted, conflicts will be abated by other means, such as pruning. Therefore, no tree removal impacts are shown to occur within shoreline jurisdiction. Hedges and small weedy vegetation (less than three inches DBH) were mapped as polygons, not points. Polygons were sketched in the field based on observations then digitized in GIS using high‐resolution imagery. Vegetation attributes within polygons were averaged. No significant (regulated) trees were inventoried using this method. Resulting mapped features included in land cover mapping of the CAIA are vegetation points with the recorded canopy (or radius) applied creating circular “tree footprints” and polygons representing varying densities of smaller weedy vegetation with the potential to reach a height of 15 feet or more. Using inventoried tree point data and incorporation of 3D design data depicting proposed pole heights and vertical wire alignment, tree impacts related to the construction of the Project were quantified. Canopy cover for the anticipated trees to remain and trees to be removed or maintained was then mapped and overlaid, resulting in a polygon layer depicting the extent of anticipated canopy The Watershed Company January 2018 VII preservation and canopy loss. This data was incorporated into the land cover data, further refining existing land cover into eight general land cover types: • Forested to be removed (canopy loss) with understory • Forested to be removed, no understory • Forested to remain (canopy preservation) with understory • Forested to remain, no understory • Understory vegetation, unforested • Other (generally lawn) • Developed • Water Impact Characterization As the work associated with this permit application includes improvements on two powerline corridors—the Energize Eastside and Lake Tradition lines—two approaches were used to calculate critical area impacts within the City of Renton. Energize Eastside 230K Line Proposed development areas associated with the Energize Eastside Project were mapped using geometry from design files and data provided by PSE. As described by PSE, work proposed in Renton could be classified into eight types and maintained in the long term as described in the following table. The Watershed Company January 2018 VIII These proposed work areas were then intersected with the land cover data set described above. The result was a set of polygons defining pre‐Project conditions (land cover data set values) and post‐Project conditions (proposed work and long‐term condition values). Differences between post‐Project conditions and pre‐Project conditions, or impacts, were then characterized as one of four types – permanent, conversion, temporary, or no change – based on the nature of the change on the ground. These characterization types are defined in the matrix below. Proposed Work Long term Condition Pole footprint Developed Pole buffer, describes an approximate 6‐foot buffer around the proposed poles that will be disturbed during construction and tree growth will be managed long‐term Mixed Vegetation (Height maintained at 15 feet or where 20 feet of vertical clearance is provided beneath the vertical curvature of the lowest wire) Access route, describes approximate path used during construction activities Mixed Vegetation (Height may be maintained depending upon location relative to wire alignment) Stringing sites* Mixed Vegetation (Height may be maintained depending upon location relative to wire alignment) Wire zone (WZ) Mixed Vegetation (Height maintained at 15 feet or where 20 feet of vertical clearance is provided beneath the vertical curvature of the lowest wire) Managed right‐of‐way (MROW) Mixed Vegetation (Height maintained at 15 feet or where 20 feet of vertical clearance is provided beneath the vertical curvature of the lowest wire) Pole work area, approximate temporary disturbance related to pole construction Mixed Vegetation (Height may be maintained depending upon location relative to wire alignment) Maintained legal right‐of‐way (LROW), encompasses the areas of LROW where PSE intends to exercise long‐term vegetation management Mixed Vegetation (Height maintained at 70 feet) * Note: Impacts from stringing sites are captured within the footprints of other proposed work activities. During construction work associated with stringing sites, adjustments may be made in the field to avoid, minimize, or mitigate impacts on critical areas should they occur. The Watershed Company January 2018 IX Existing Land Cover Types Impact Description Long-term Condition1 Forested to be removed with understory Forested to be removed, no understory Forested to remain with understory Forested to remain, no understory Understory Other (mostly lawn) Developed Water Proposed Activities Pole footprint Developed P P P P P P NC N/A Pole buffer Mixed vegetation2 C C T T T T NC N/A Access route Mixed vegetation2 C C T T T T NC N/A Pole work area Mixed vegetation2 C C T T T T NC N/A Wire zone Mixed vegetation2 C C NC NC NC NC NC N/A Managed ROW Mixed vegetation2 C C NC NC NC NC NC N/A Maintained Legal ROW Mixed vegetation2 C C NC NC NC NC NC N/A Type of Impact based on proposed activity, long term condition, and existing land cover type: P = Permanent to developed C = Vegetation conversion (not developed) T = Temporary impact, can be restored to existing land cover NC = No Change N/A = Not applicable/does not occur 1 Long term condition determined in coordination with PSE. 2 Subject to varying height restrictions described in Section 3.3.4. The Watershed Company January 2018 X Lake Tradition 115K Line Work associated with the Lake Tradition line is restricted to one area of the project corridor, affecting approximate five adjacent spans. Work includes resetting existing poles, adding new poles, and rehanging lines on existing poles. Due to the limited work and the utilization of existing poles, no vegetation impacts due to conflicts between wire height and tree height are anticipated. Therefore, for new or replaced poles along the Lake Tradition line, tree removal impacts were calculated based solely on proximity to proposed pole work areas. The long‐term condition and impact characterization for “pole work area” was consistent with the parameters of the Energize Eastside analysis, as described by the tables in the preceding section. Critical Areas Impact Assessment Application of the matrix yielded a map showing a full characterization of permanent, conversion, and temporary impacts associated with the Project. This impact characterization layer was then intersected with each individual mapped critical area in order to locate, characterize, and quantify impacts to that critical area. The results were summarized by critical area, and for wetlands and streams, by drainage sub‐basin. The ending table summarizes the data sources used for the critical areas analysis. Quality Assurance Review of Analysis Steps and Results Internal review of CAIA steps and results has occurred throughout the process described above and will be ongoing as the analysis is refined. Ecologists, arborists, GIS analysts, and planners worked collaboratively to ensure all appropriate critical areas were incorporated into the maps and where appropriate, classified and buffered according the local jurisdiction regulations. GIS analysts created the land cover base map, compiled from a variety of sources. Land cover classifications were reviewed for quality assurance first through the GIS department by comparing mapped data to high resolution aerial imagery. Following review by the GIS analysts, the land cover map was reviewed by an ecologist against delineation field notes and recollections from field work activities. Project elements and site plans have been provided by, and reviewed with, PSE Project staff. The mapped location and long‐term condition of Project elements is based upon discussions with PSE regarding best management practices and standard PSE programs and policies. All components of the CAIA have been generated/authored by reputable sources and have been cross‐checked internally for consistency. Quantified and depicted The Watershed Company January 2018 XI impacts resulting from the CAIA have been reviewed by ecologists for quality assurance to the extent feasible. Impact results will continue to be reviewed for accuracy as the Project plans and impact areas are refined and finalized. Limitations This analysis relies on a series of data products produced using different scales and methods; therefore, mapped features may not align with the planned real‐ world layout of proposed corridor facilities. Ground‐truthing of these results may reveal inaccuracies. Furthermore, as some features and design geometries were translated from AutoCAD into ArcGIS, some geometric refinements were necessary to address gaps and other issues, which could affect the accuracy of the analysis results. The Watershed Company January 2018 XII Data Inventory Elements and Information Sources: Inventory Element Information Gathered Data Source(s) Assumptions/Limitations Proposed Development Topographic surface data Point map of surface elevations Puget Sound Energy (PSE) tabular data (via email R. Weider); date received 4/19/2017 The Watershed Company (TWC) Point elevations generated from LIDAR flight by consultant to PSE; flight date unknown Data was post‐processed to generate a 3D surface map using ArcGIS software Proposed Energize Eastside Project Improvements Pole structures Wire alignments, including alternate alignment Pole construction work areas Proposed temporary construction access routes Stringing sites PSE (via email R. Weider, K. Purnell), design drawings in AutoCAD; date received: 6/30/2017‐11/6/2017 TWC Reflects pole and wire design configuration from June 30, 2017, with updates through November 6, 2017 Design may be subject to revision or update based on regulatory comments, field conditions, or other factors Cadastral Datasets & Features Land Cover Development and impervious areas Other Tree canopy Understory vegetation King County 2009 impervious dataset and 2015‐2016 aerial data PSE high‐resolution aerial photography; date received 7/7/2015 APS Surveying, digital survey; date received 5/18/2016 TWC Impervious dataset from King County, last updated 2009 Vegetation survey by TWC between 2015 and 2017 “Developed” category includes roads, structures, and heavily disturbed areas, such as compacted unimproved roadways “Other” category observed to be mostly lawn based on visual observation of aerial photographs, but could include other conditions Survey data was post‐processed to isolate and generate geospatial feature classes using ArcGIS software Parks Park locations City of Renton (downloaded 4/6/17) Park boundaries current as of 1/14/2017 The Watershed Company January 2018 XIII Inventory Element Information Gathered Data Source(s) Assumptions/Limitations City limits Shapefile polygons City of Renton (downloaded 6/2/17) Does not reflect annexations beyond download date. Parcels Shapefile polygons City of Renton (downloaded 6/2/17) Does not reflect parcel subdivisions beyond download date. Regulated Critical Areas Streams and Riparian Areas (RMC 4‐3‐050(G)(7)) Streams with study corridor Stream buffers TWC City of Renton (downloaded 4/6/17) Streams delineated by TWC between 2015 and 2017 Feature buffers assigned according to City of Renton 2015 Critical Areas Ordinance (CAO) Floodplains See Flood Hazard Areas Wetlands (RMC 4‐3‐ 050(G)(9)) Delineated wetlands within study corridor Wetland buffers TWC City of Renton (downloaded 4/6/17) Wetlands delineated by TWC between 2015 and 2017 Wetland feature ratings based on 2014 rating system Feature buffers assigned according to City of Renton 2015 Critical Areas Ordinance (CAO) Fish and Wildlife Habitat Conservation Areas (RMC 4‐ 3‐050(G)(6)) Priority habitat and species data (PHS) Endangered/listed species WDFW (received 6/27/2017) USFWS No FWHCA features occur within project area Scale may not be sufficient to capture individual occurrences or observations along the corridor Accuracy does not supersede observation by PSE staff Geologic Hazard Areas: Landslide hazard areas (RMC 4‐3‐050 (G)(5)(b)) Erosion hazard areas RMC 4‐3‐050 (G)(5)(c)) Steep slopes (RMC 4‐3‐ 050 (G)(5)(a)) Landslide hazard areas City of Renton (downloaded 4/6/17) TWC Data describes landslide hazards defined by City of Renton CAO Data is not suitable for smaller scale site‐ specific analysis; “Observation of actual on‐ site conditions is required to determine if a particular parcel is in a landslide hazard area or not” No very high landslide areas or buffers exist in the project area The Watershed Company January 2018 XIV Inventory Element Information Gathered Data Source(s) Assumptions/Limitations Coal mine hazard areas (RMC 4‐3‐050 (G)(5)(e)) Seismic hazard areas (RMC 4‐3‐050 (G)(5)(d)) Erosion hazard areas City of Renton (downloaded 4/6/17) Data describes erosion hazards defined by Renton CAO Data is not suitable for smaller scale site‐ specific analysis Steep slope hazard areas City of Renton (downloaded 4/6/17) TWC GeoEngineers TWC categorized City of Renton steep slope data through analysis of PSE LIDAR surface data. Areas where slope >= 40% and >15ft of relief were categorized as “protected” No steep slope buffers are required according to City of Renton CAO under table RMC 4‐3‐050 (G)(2) Coal mine hazard areas City of Renton (downloaded 4/6/17) Identification of historical coal mine areas as defined by Renton CAO Seismic hazard areas City of Renton (downloaded 4/6/17) Identification of areas subject to potential surficial liquefaction based on DNR liquefaction data Flood hazard areas (RMC 4‐ 3‐050 (G)(4)) Flood hazard areas City of Renton (downloaded 4/6/17) Data displays the Cedar River Floodway and 100‐Year Floodplain as defined by Renton CAO Shoreline Jurisdiction (RMC 4‐3‐090(B)(3)) Shoreline jurisdiction TWC Shoreline jurisdiction includes 200‐foot area around mapped floodway, as provided by City of Renton, as well as associated wetlands, as delineated by TWC Wellhead protection areas (RMC 4‐3‐050 (G)(8)) Wellhead protection areas City of Renton (downloaded 4/6/2017) Data displays aquifer protection zone areas A P P E N D I X E Geological Hazards Report Revised Targeted Critical Areas Geologic Hazards Energize Eastside Project Renton, Washington for Puget Sound Energy January 11, 2018 Revised Targeted Critical Areas Geologic Hazards Energize Eastside Project Renton, Washington for Puget Sound Energy January 11, 2018 8410 154th Avenue NE Redmond, Washington 98052 425.861.6000 January 11, 2018 | Page i File No. 0186-871-06 Table of Contents INTRODUCTION ......................................................................................................................................................... 1 LOCAL REGULATIONS .............................................................................................................................................. 1 Code Definitions for Hazard, Hazards Areas, Wellhead Protection Zones and Buffers .................................. 1 EXISTING CONDITIONS ............................................................................................................................................ 4 Field Observations ............................................................................................................................................... 5 Honey Dew Creek .......................................................................................................................................... 5 Cedar River North Slope ............................................................................................................................... 5 Cedar River South Slope ............................................................................................................................... 6 IMPACT ASSESSMENT ............................................................................................................................................. 6 Access Construction ............................................................................................................................................ 7 Pole Installation ................................................................................................................................................... 7 Conclusions .......................................................................................................................................................... 7 Conceptual Impact Mitigation Strategy .............................................................................................................. 8 Vegetation Management and Tree Removal ............................................................................................... 8 CODE COMPLIANCE .............................................................................................................................................. 10 4-3-050 (G2) – Development Standards – Critical Area Buffers ................................................................... 10 4-3-050 (G5f) – Development Standards for Geologically Hazardous Areas – Protected Slopes............... 10 4-3-050 (G5g) – Development Standards for Geologically Hazardous Areas – Sensitive Slopes; Medium, High and Very High Landslide Hazards; High Erosion Hazards ...................................................................... 10 4-3-050 (G5i(ii)) – Development Standards for Geologically Hazardous Areas – Coal Mine Hazards Found during Construction .......................................................................................................................................... 10 4-3-050 (G5d) – Development Standards for Geologically Hazardous Areas – Seismic Hazards Found during Construction .......................................................................................................................................... 11 4-3-050 (G8) – Development Standards for Geologically Hazardous Areas – Wellhead Protection Zones Found during Construction ............................................................................................................................... 11 LIMITATIONS .......................................................................................................................................................... 12 REFERENCES ........................................................................................................................................................ 12 January 11, 2018 | Page 1 File No. 0186-871-06 INTRODUCTION GeoEngineers, Inc. (GeoEngineers) is pleased to present this revised report with the results for targeted critical areas evaluation of specific geologic hazards identified by Puget Sound Energy (PSE) for the Energize Eastside Project. Our services have been provided in general accordance with the proposal between GeoEngineers and PSE dated June 21, 2017. These services were authorized by Kelly Purnell with PSE on June 15, 2017, and formal authorization was received on June 26, 2017. This revised report supersedes our previous report and addresses comments provided by PSE on January 4, 2018. The project area is located along existing PSE rights-of-way and includes areas within the City of Renton. We previously provided a geologic hazard evaluation for various routes under consideration, including the route evaluated within this document, in a separate report submitted to PSE on December 19, 2014 (GeoEngineers 2014). The geologic hazards evaluation included in this report focuses on a desktop review for erosion, steep slope, landslide and coal mine hazard areas, and seismic hazards as assigned by PSE, relative to proposed vegetation management activities, including tree-removal required for construction access and pole replacement. PSE also requested an evaluation of wellhead protection areas mapped within the project area. PSE has provided specific locations for evaluation and a map developed by others that shows proposed pole replacement activities, including proposed tree removal, vegetation management zones and access roads. LOCAL REGULATIONS GeoEngineers assessed local regulations in the City of Renton Critical Areas Regulations, 4-3-050, for the project areas identified by PSE that coincide with regulated geologic hazard areas. Code Definitions for Hazard, Hazards Areas, Wellhead Protection Zones and Buffers GeoEngineers assessed local regulations in the Renton Municipal Code, Definitions, Chapter 4-11 and Critical Areas, Chapter 4-3-050 for selected geologic hazard areas and wellhead protection zones. ■ Erosion: The wearing away of the ground surface as a result of the movement of wind, water and/or ice (Renton Municipal Code, 4-11-050). ■ Erosion Hazard Areas: Low Erosion Hazard (EL): Areas with soils characterized by the Natural Resource Conservation Service (NRCS) as having slight or moderate erosion potential, and a slope less than fifteen percent (Renton Municipal Code, 4-3-050). High Erosion Hazard (EH): Areas with soils characterized by the NRCS as having severe or very severe erosion potential, and a slope more than fifteen percent (Renton Municipal Code, 4-3-050). There are no buffer requirements for low or high erosion hazards. ■ Seismic Hazard: Seismic are not described within the Definitions section of the Renton Municipal Codes as of December 19, 2017 (Renton Municipal Code 4-11-030). However, the Critical Areas January 11, 2018 | Page 2 File No. 0186-871-06 Regulations pertaining to Seismic Hazards does provide a description in Renton Municipal Code and are as follows: Low Seismic Hazard (SL): Areas underlain by dense soils or bedrock. These soils generally have site classifications of A through D, as defined in the International Building Code, 2012. (Renton Municipal Code 4-3-050). High Seismic Hazard (SH): Areas underlain by soft or loose, saturated soils. These soils generally have site classifications E or F, as defined in the International Building Code, 2012. (Renton Municipal Code 4-3-050). There are no buffer requirements for high seismic hazards. ■ Slopes, Steep (Also referred to as Steep Slopes): A hillside, or portion thereof, which falls into one of two (2) classes of slope, sensitive or protected (Chapter 11, Definitions 4-11-190). Slope, Protected: A hillside, or portion thereof, with an average slope, as identified in the City of Renton Steep Slope Atlas or in a method approved by the City, of forty percent (40%) or greater grade and having a minimum vertical rise of fifteen feet (15'). Slope, Sensitive: A hillside, or portion thereof, characterized by: (1) an average slope, as identified in the City of Renton Steep Slope Atlas or in a method approved by the City, of twenty five percent (25%) to less than forty percent (40%); or (2) an average slope, as identified in the City of Renton Steep Slope Atlas or in a method approved by the City, of forty percent (40%) or greater with a vertical rise of less than fifteen feet (15'), abutting an average slope, as identified in the City of Renton Steep Slope Atlas or in a method approved by the City, of twenty five percent (25%) to forty percent (40%). This definition excludes engineered retaining walls. There is no established critical area buffer for steep slopes within Renton. ■ Landslide Hazards: Landslide Hazards are not described within the Definitions Section (4-11-030) in the Renton Municipal Code as of December 19, 2017. However, the Critical Areas Regulations pertaining to Landslide Hazards are defined in Renton Municipal Code as follows: Low Landslide Hazard (LL): Areas with slopes less than fifteen percent (Renton Municipal Code 4-3-050). Medium Landslide Hazard (LM): Areas with slopes between fifteen percent and forty percent and underlain by soils that consist largely of sand, gravel or glacial till (Renton Municipal Code 4-3-050). High Landslide Hazards (LH): Areas with slopes greater than forty percent, and areas with slopes between fifteen percent and underlain by soils consisting largely of silt and clay (Renton Municipal Code 4-3-050). Very High Landslide Hazards (LV): Areas of known mapped or identified landslide deposits (Renton Municipal Code 4-3-050). According to City of Renton’s Critical Area Regulations, a critical area buffer is not required for low to high landslide hazards. The established critical area minimum buffer for very high landslide hazards is 50 feet from the top, toe and sides of the slope. January 11, 2018 | Page 3 File No. 0186-871-06 ■ Coal Mine Hazard: Coal Mine Hazard are not described within the Definitions section of the Renton Municipal Codes as of September 18, 2017 (Renton Municipal Code 4-11-030). However, the Critical Areas Regulations pertaining to Coal Mine Hazards does provide a description in Renton Municipal Code and are as follows; Low Coal Mine Hazard (CL): Areas with no known mine workings and no predicted subsidence. While no mines are known in these areas, undocumented mining is known to have occurred (Renton Municipal Code 4-3-050). Medium Coal Mine Hazard (CM): Areas where mine workings are deeper than two hundred feet (200') for steeply dipping seams, or deeper than fifteen (15) times the thickness of the seam or workings for gently dipping seams. These areas may be affected by subsidence (Renton Municipal Code 4-3-050). High Coal Mine Hazard (CH): Areas with abandoned and improperly sealed mine openings and areas underlain by mine workings shallower than two hundred feet (200') in depth for steeply dipping seams, or shallower than fifteen (15) times the thickness of the seam or workings for gently dipping seams. These areas may be affected by collapse or other subsidence (Renton Municipal Code 4-3-050). The are no established critical area buffers for coal mine hazard areas. Wellhead Protection Area: The definition of Wellhead Protection Area is not provided in the Definitions Section of the Renton Municipal Codes as of December 20, 2017 (4-11-230). However, the Critical Areas Regulations pertaining to Wellhead Protection Areas do provide the following description as follows; a. Applicability: Developments, facilities, uses and activities discussed in this subsection shall comply with the applicable provisions and restrictions of this Section and chapters 4-4, 4-5, 4-6, 4-9, and 5-5 RMC for the Wellhead Protection Areas, as classified below, in which the developments, facilities, uses and activities are located, except as preempted by Federal or State law. (Renton Municipal Code 4-3-050). i. Wellhead Protection Areas: Wellhead Protection Areas are the portion of an aquifer within the zone of capture and recharge area for a well or well field owned or operated by the City. ii. Wellhead Protection Area Zones: Zones of a Wellhead Protection Area are designated to provide graduated levels of Wellhead Protection Area recharge. Zone boundaries are determined using best available science documented in the City of Renton Wellhead Protection Plan, an appendix of the City of Renton Water System Plan, as periodically updated. The following zones may be designated: (a) Zone 1: The land area situated between a well or well field owned by the City and the three hundred sixty five (365) day groundwater travel time contour (Renton Municipal Code 4-3-050). (b) Zone 1 Modified: The same land area described for Zone 1 but for the purpose of protecting a high-priority well, wellfield, or spring withdrawing from a confined January 11, 2018 | Page 4 File No. 0186-871-06 aquifer with partial leakage in the overlying or underlying confining layers. Uses, activities, and facilities located in this area are regulated as if located within Zone 1 except as provided by this subsection G8 (Renton Municipal Code 4-3- 050). (c) Zone 2: The land area situated between the three hundred sixty five (365) day groundwater travel time contour and the boundary of the zone of potential capture for a well or well field owned or operated by the City. If the aquifer supplying water to such a well, well field, or spring is naturally protected by confining overlying and underlying geologic layers, the City may choose not to subdivide a Wellhead Protection Area into two (2) zones. In such a case, the entire Wellhead Protection Area will be designated as Zone 2 (Renton Municipal Code 4-3-050). d. Wellhead Protection Areas: The City may require an applicant to prepare a hydrogeologic study if the proposal has the potential to significantly impact groundwater quantity or quality, and sufficient information is not readily available. Such a report shall be prepared by a qualified professional at the applicant’s expense. Report content requirements may be specified by the City in accordance with State or Federal guidelines or tailored to the particular development application. Peer review of the applicant’s report may be required in accordance with this subsection F (Renton Municipal Code 4-3-050). The are no established critical area buffers for wellhead protection zones. EXISTING CONDITIONS GeoEngineers reviewed the City of Renton COR Maps, King County iMap and a previous report, titled Geologic Hazards Evaluation and Preliminary Geotechnical Engineering Services report, submitted to PSE in December 2014, to assess existing conditions in the project area within the City of Renton (GeoEngineers 2014). Based on information presented in that report and a review of existing maps, the existing geology consists mainly of glacial drift, recessional outwash, glacially consolidated till and advance outwash deposits, with the exception of localized areas of alluvium, volcanic deposits and rocks, marine sedimentary rocks and artificial fill. Soil types anticipated in the project area include mainly silty gravel, silty sand and silt. Both steep sensitive slopes and protected slopes were observed locally within the project area. However, outside of the Cedar River corridor and the Honey Dew Creek corridor, the steep sensitive slopes where tree removal is proposed are generally developed and include rockeries, landscaped residential slopes, and managed right-of-way areas that are unlikely to be adversely impacted based on their current configuration and use. Protected steep slopes that include slopes of 40 percent or greater are observed locally within the project area; however, no access roads or pole replacement activities will occur within the mapped protected slopes. Tree removal for vegetation management purposes that is proposed on the protected slopes occurs in the regional areas of steep slopes, namely within the Honey Dew Creek drainage and the Cedar River drainage. January 11, 2018 | Page 5 File No. 0186-871-06 High erosion hazard areas, sensitive and protected steep slopes, and moderate landslide hazard areas are mapped at the Honey Dew Creek and Cedar River drainages, within the project area (City of Renton, City of Renton COR Maps). A prehistoric, deep-seated landslide is mapped on the southern side of the Cedar River drainage, within the project area (King County, iMap). Moderate coal mine hazard areas also are mapped in the Cedar River drainage, within the project area (City of Renton, COR Maps). No high coal mine hazards areas (CH) are mapped within the project site (City of Renton, COR maps). No high landslide hazard areas (LH) or very high landslide hazard areas (LV) are mapped within the project site (City of Renton, COR Maps). Moderate landslide hazards are mapped locally within Honeydew Creek and the Cedar River Valley, High Seismic Hazards are mapped within the project corridor for a distance of approximately 470 feet south of SR 169 within the Cedar River area in areas mapped with recent alluvial deposits. Wellhead Protection Zones 1 and 2 are mapped within the project vicinity. An approximate 3,000-foot segment along Monroe Avenue NE is not mapped within a wellhead protection zone. Zone 1 is located within Cedar River corridor that includes SR 169 and Zone 2 is located in the remaining majority of the project area. Field Observations A field reconnaissance was performed on June 28, 2017, to evaluate the geologic hazard areas identified along the slopes of Honey Dew Creek and the Cedar River. The reconnaissance was divided into three areas: Honey Dew Creek (north and south slopes), north slope of Cedar River, and south slope of Cedar River. Our field observations are summarized as follows. Honey Dew Creek The project area is within an existing utility corridor with overhead power lines. Vegetation consists of evergreen trees with bowed or pistol-butted trunks that suggest soil creep or episodic movement, deciduous trees and an understory that includes sword fern, blackberry, salal, Oregon grape and occasional hydrophilic plants (horsetail). Loose recessional deposits of sand and gravel are commonly exposed at the surface within the drainage. The slope on the south side of Honey Dew Creek is inclined between 65 to 100 percent locally. We observed two landslide scarps with 3 to 6 feet of vertical displacement and widths of 15 to 20 feet, where exposed soils are subject to localized erosion on the south slope, approximately 40 feet upslope of the Honey Dew Creek channel. The terrain on the slope south of the creek is somewhat hummocky. Localized groundwater seepage and/or hydrophilic plants were observed at an elevation approximately 10 feet upslope of Honey Dew Creek on both the south and north slopes, where a contact between the overlying outwash deposits and an underlying laminated silt was observed. The slope on the north side of Honey Dew Creek is commonly inclined between 60 to 70 percent, and includes a 15-foot-deep tributary drainage swale with sidewalls inclined up to 80 percent. Cedar River North Slope The project area within the Cedar River valley wall north slope, located north of SR 169, is within an existing utility corridor that includes overhead power lines. Vegetation consists primarily of deciduous January 11, 2018 | Page 6 File No. 0186-871-06 trees with occasional evergreens, and an understory that includes fern, salal, blackberry and Scotch broom. The conifer trees are generally straight and in a vertical growth position. Loose recessional deposits of sand and gravel are commonly exposed at the surface. The slope is inclined between 60 to 85 percent. We observed a small landslide scarp with 8 feet of vertical displacement and a width of 10 feet near the top of the slope. At mid-slope, we observed a larger arcuate landslide scarp with approximately 15 feet of vertical displacement and a width of about 100 feet. Conifer trees near the larger landslide commonly have bowed or pistol-butted trunks. A large hemlock tree (approximately 18 inches, diameter breast height) is growing within the landslide mass, indicating that the landslide is relatively old. The slope also is mapped within a moderate coal mine hazard area (City of Renton, COR MAPs), but we did not observe any evidence of land subsidence, sinkhole formation or deposits associated with coal mining activities. Cedar River South Slope The project area within the Cedar River valley wall south slope, located south of the Cedar River Trail Walk, is within an existing utility corridor that includes overhead power lines. Vegetation consists of deciduous and evergreen trees, with a dense understory that includes fern, salal, Oregon grape, blackberry, grass and nettles. The conifer trees are generally straight and upright, with occasional slightly bowed trunks. Loose recessional deposits of sand and gravel are commonly exposed at the surface. A large prehistoric, deep-seated landslide mapped by King County covers the corridor slope south of the Cedar River. The slope is commonly inclined between 30 to 60 percent. The terrain is slightly hummocky, but we did not observe any evidence of landslide reactivation or recent activity at the time of our site reconnaissance. The slope is mapped within a moderate coal mine hazard area (City of Renton, COR MAPs), but we did not observe any evidence of land subsidence or coal mining activities. IMPACT ASSESSMENT There are two primary ways in which tree removal activities may impact erosion and slope stability on steep slopes or landslide hazard areas. After tree removal (where the stump is left in place), root decay causes both the numbers of roots and the tensile strength of the remaining individual roots to decrease with time (Burroughs and Thomas 1977). Studies show that the period of minimum root strength is typically from 3 to 5 years after harvest (Ziemer 1981a; 1981b), but can extend up to 10 to 20 years, depending on the tree species. For example, minimum root strength in evergreens is typically 10 years after harvest, alders have a minimum root strength of 5 to 10 years after harvest, and maples typically maintain full root strength after harvest. The reductions in root strength result in a net decrease in the cohesive strength of the near-surface soil mass. Tree removal also might modify surface and subsurface hydrology. Tree removal may increase soil moisture by reducing canopy interception and evapotranspiration. Ground-based yarding equipment can compact soil, which may alter hydrologic processes in certain soil types. Elevated groundwater levels decrease the stability of slopes by reducing the shear strength of the soil and by adding additional weight. The probability of erosion and landsliding from elevated groundwater levels depends on the magnitude of the increase and the existing stability of the slope. The magnitude of potential changes in groundwater levels from tree removal is highly variable and depends on several factors, including the tree size, silviculture, subsurface conditions and topography. January 11, 2018 | Page 7 File No. 0186-871-06 In general, tree removal will increase the potential impact on wellhead protection zones, erosion and slope stability for erosion hazard areas, steep slopes or landslide hazard areas. Fewer impacts are expected in areas where tree removal is isolated to one or two trees, and the erosion, steep slope or mapped landslide hazard area is otherwise stable and well vegetated. Tree removal is not anticipated to impact mapped moderate coal mine or high seismic hazards. Additionally, fewer impacts are expected at the toe of the slope, compared to tree removal within the body or at the top of the slope. Access Construction Temporary access routes will generally follow previously established access trails and routes and, in some cases, will cross existing developed landscape. Therefore, little cutting or filling will be required. Small amounts of quarry spalls might be necessary to stabilize portions of existing routes. Many of the existing routes are overgrown with vegetation and, thus, will need to be cleared. Standard erosion control best management practices (BMPs) should be followed during construction (clearing and use of temporary access routes). Following completion of construction activities, restoration BMPs such as mulching and/or placing jute matting should be implemented. Pole Installation Where new poles are located in steep slope or landslide hazard areas, a temporary working bench might be necessary to install the pole. These benches may vary from about 10 by 10 feet to 30 by 30 feet in dimension. The same considerations discussed above for access routes also apply to benches needed for pole installation. We recommend that clearing activities be restricted to that necessary to auger the hole for the pole. Recommendations for the design and construction of poles are presented in our Geotechnical Engineering Services report dated June 8, 2016. In general, most of the site soils along the proposed route consist of recessional deposits or glacially consolidated deposits, and in some limited locations, bedrock. These soils should provide adequate support for the new poles, and it is our opinion that once the pole is installed, the pole will not adversely impact slope stability; the pole should actually provide additional resisting force against slope failure, provided the pole is embedded to a sufficient depth. New poles are proposed in areas mapped as a medium/moderate coal mine hazard, which is defined in Renton Municipal Code 4-3-050 as areas where the mine workings are deeper than 200 feet for steeply dipping seams or deeper than 15 times the thickness of the seam or workings for gently dipping seams. Based on the results of the subsurface soil investigation conducted in 2014 and our knowledge of the geologic conditions in this area, the installation of new poles in these areas is not anticipated to impact mapped moderate coal mine hazards. Conclusions Mapped high erosion, high seismic, sensitive and protected steep slopes and moderate or unclassified landslide hazard areas are present within the project area. Outside of the Honey Dew Creek and Cedar River valley areas, most of the remaining areas are developed and include rockeries, landscaped residential or commercial development slopes and cut slopes associated with roadways, and include the following: ■ One tree removed in the managed corridor east of North 23rd Court; January 11, 2018 | Page 8 File No. 0186-871-06 ■ Multiple trees removed east of the residence at 2101 Newport Court NE; ■ One tree removed east of the residence at 3118 NE 18th Street; ■ One tree removed on the east side of the Goodwill parking lot at 3208 NE Sunset Boulevard; ■ Multiple trees removed on the east side of an existing parking lot for 3224 NE 12th Street; ■ Multiple trees removed on the east side of existing residences from 1082 to 1074 Lynnwood Avenue NE; ■ One tree removed on the campus of the Renton Technical College; and ■ One tree removed west of the apartment complex at SE 8th Street and Harrington Place SE. Localized areas of high erosion, sensitive and protected steep slopes, and moderate or unclassified landslide hazard areas in the project area include the Honey Dew Creek drainage and the Cedar River drainage, which include slopes greater than 40 percent with a 15-foot vertical elevation rise. The Cedar River Area also includes a localized high Seismic hazard within the mapped alluvium. The project area is within an existing right-of-way that is maintained for vegetation by PSE. The proposed removal of selected trees in the Honey Dew Creek drainage, selected trees north of the Cedar River, and selected trees south of the Cedar River is consistent with the management activities of the existing power line right-of-way and is not anticipated to impact the mapped wellhead protection zones and geologic hazard areas within these drainage areas, provided that no tracked or rubber-tired equipment is used to remove the trees, in our opinion. Within the Cedar River corridor no trees will be removed within the shoreline/wetland areas. The proposed removal of trees in the Honey Dew Creek drainage is located upslope of any identified recently active slope failures and is not anticipated to exacerbate localized slope failures, in our opinion. Conceptual Impact Mitigation Strategy Vegetation Management and Tree Removal For vegetation management and tree removal in the City of Renton within the mapped geohazard areas outlined in the proposed PSE project segment, GeoEngineers suggests the following options for mitigating impacts after tree removal. In general, to limit impacts on erosion and slope stability from vegetation management and tree removal within steep slope and landslide hazard areas, the sites should be accessed by foot to reduce equipment impacts. Hand cutting with chainsaws should be implemented to trim branches and remove trees. Stumps should remain in place, but can be cut to ground level. Branches, limbs, trunks and other tree debris should be chipped and scattered around the removal site within the right-of-way. Where chipping is not feasible, unchipped tree debris can be scattered. We recommend that trees are felled across the fall line and are left perpendicular to slope if they are not chipped. In areas where tree removal is clustered, erosion control BMPs, such as grass seeding, leaving stumps, scattering straw, and/or replacement planting of native shrubs or small trees, should be implemented to reduce concentrated flows and minimize disturbance. January 11, 2018 | Page 9 File No. 0186-871-06 In areas where houses are located within 25 to 50 feet of vegetation management and tree removal, all tree debris should be removed from the owner’s property and communication with the property owner is suggested to identify possible reseeding, replacement tree or shrub, or landscaping options. If agreeable to the property owner, it is possible that the tree trunk can be cut and left below ground surface to maintain root strength (up to 5 to 10 years, depending on tree type), and a replacement tree or shrub may be planted near the trimmed trunk. Within the Honey Dew Creek and Cedar River drainage areas, where erosion, moderate landslide and steep slope hazard areas are mapped, it is recommended that tree removal be done by hand cutting with chainsaws, stumps left in place, and tree debris scattered. Within the Honey Dew Creek drainage, replacement planting with native shrubs is suggested to increase root strength after tree removal and to reduce impacts within the landslide hazard area. Reestablish Access Routes Where vegetation clearing is required to reestablish the access on existing trails and access routes, BMPs should be implemented; these BMPs can include, but are not limited to: outsloping road surfaces, crowning road surfaces (where appropriate, such as at ridge tops and where roads climb gently inclined surfaces) and installing water bars or rolling dips at regularly spaced intervals to avoid concentrating surface water flow along the road surface. The spacing depends on the grade of the route, the soil type present, proximity to streams and the intended use of the road (i.e., temporary or permanent). Most, if not all, access routes will be temporary and will be abandoned following construction of the transmission line. No temporary access roads will cross any drainages situated in geologic hazard areas. It is the contractor’s responsibility to complete construction work safely and in accordance with applicable local, state and federal laws. After access use is complete, where it is deemed necessary, limited regrading of the access route is recommended to avoid concentrating surface runoff along tracks, ruts or other potential flowpaths. Following completion of construction activities, the construction access routes will be graded to a stable free-draining configuration, treated with appropriate erosion control measures, such as mulching and/or placing jute matting and installation of water bars as needed to control runoff, and seeded. If jute mat is determined a necessary BMP, the jute mat should be anchored at the upslope and downslope ends and secured with staples per the manufacturer’s recommendations. Pole Installation Where a bench is required to install a pole on a steep slope or landslide hazard area, the recommendations presented above for temporary access roads also apply for pole installation. Appropriate erosion control BMPs should be implemented during construction, and the disturbed area should be restored after pole installation by seeding or revegetating and covering the disturbed area with appropriate BMPs. Soil removed from the new pole excavations should be scattered into vegetation away from the landscaped areas. Any areas of exposed soil must be seeded and mulched (or covered with hog fuel) to prevent transport of sediment down the steep slopes or into the seepage area during rain events. If the work area is wet or has standing water, driving mats should be used under all equipment and all soils should be removed from the site for off-site disposal. For poles located in geologic hazard areas, the old poles should be cut off approximately 1 to 2 feet below the ground surface and the remaining portion of each pole left in place. If poles installed on slopes January 11, 2018 | Page 10 File No. 0186-871-06 steeper than 2H:1V (horizontal to vertical), they should be embedded at least 3 feet deeper than the typical design embedment. CODE COMPLIANCE 4-3-050 (G2) – Development Standards – Critical Area Buffers The critical area buffer width for very high landslide hazard areas is 50 feet. Buffers are not required for steep slopes or high or moderate landslide hazards, based on the results of a geotechnical report and/or independent review. Response to Code Requirement: The site does not include any mapped very high landslide hazard areas (LV) and, as such, there are no required buffers in the project area. The proposed activities include vegetation management and tree removal and access routes (associated with the proposed pole replacement activities) that will be followed by mitigation measures to reduce potential impacts to geologic hazards. These hazards include landslide and steep slope hazards. Possible mitigation measures include a variety of BMPs to reduce potential impacts to geologic hazards in the vicinity of neighboring properties, including plant replacement, scattering trimmed or removed tree debris, and chipping wood to reduce potential impacts to work areas as appropriate. Removal of vegetation by hand and/or using limited access machinery will reduce potential impacts to landslide and steep slope hazard areas. It is our opinion that the proposed project will not require additional buffers. There are no established critical area buffers for erosion hazard areas or coal mine hazard areas. 4-3-050 (G5f) – Development Standards for Geologically Hazardous Areas – Protected Slopes Development is prohibited on protected slopes. Response to Code Requirement: No development is planned. Site activities include vegetation management and limited tree removal (associated with the pole replacement activities) within an existing utility right-of-way. No development or grading activities will be conducted on protected slopes. Replacement of existing utility systems are exempted, provided the work does not increase the footprint by more than 10 percent and that restoration shall be conducted where feasible. 4-3-050 (G5g) – Development Standards for Geologically Hazardous Areas – Sensitive Slopes; Medium, High and Very High Landslide Hazards; High Erosion Hazards During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required Response to Code Requirement: Site activities include vegetation management and limited tree removal (associated with the pole replacement activities). Weekly on-site inspections and reports documenting erosion control measures will be completed as required by the applicant. 4-3-050 (G5i(ii)) – Development Standards for Geologically Hazardous Areas – Coal Mine Hazards Found during Construction Any hazards found during any development activities shall be immediately reported to the Development Services Division. Any coal mine hazards shall be mitigated prior to recommencing construction based January 11, 2018 | Page 11 File No. 0186-871-06 upon supplemental recommendations or reports by the applicant’s geotechnical professional. During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required Response to Code Requirement: Any coal mine hazards found during the proposed vegetation management and tree removal activities associated with the pole replacement activities will be immediately reported to the Development Services Division. Any identified coal mine hazards will be mitigated prior to recommencing any activities based upon supplemental recommendations or reports by the applicant’s geotechnical professional. Weekly on-site inspections and reports documenting erosion control measures will be completed by the applicant. 4-3-050 (G5d) – Development Standards for Geologically Hazardous Areas – Seismic Hazards Found during Construction Any hazards found during any development activities shall be immediately reported to the Development Services Division. Any seismic hazards shall be mitigated prior to recommencing construction based upon supplemental recommendations or reports by the applicant’s geotechnical professional. During construction, weekly on-site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required Response to Code Requirement: No tree removal is proposed within High Seismic Hazard areas. Any seismic hazards found during the proposed vegetation management and tree removal activities associated with the pole replacement activities will be immediately reported to the Development Services Division. Any identified seismic hazards will be mitigated prior to recommencing any activities based upon supplemental recommendations or reports by the applicant’s geotechnical professional. Weekly on-site inspections and reports documenting erosion control measures will be completed by the applicant. 4-3-050 (G8) – Development Standards for Geologically Hazardous Areas – Wellhead Protection Zones Found during Construction Any potential risks to groundwater Wellhead Protection Zones found during any development activities shall be immediately reported to the Development Services Division. Any risk to groundwater wellhead protection zones shall be mitigated prior to recommencing construction based upon supplemental recommendations or reports by the applicant’s geotechnical professional. During construction, weekly on- site inspections shall be required at the applicant’s expense. Weekly reports documenting erosion control measures shall be required Response to Code Requirement: No construction dewatering is planned within the project area including Wellhead Protection Zones. Spill Prevention Control and Countermeasures (SPCC) and Temporary Erosion and Sediment Control Plans will be implemented to address potential construction related contaminant handling associated within Wellhead Protection Zones. Potential contaminant impacts to Wellhead Protection Zones associated with removal and proposed vegetation management and tree removal activities associated with the pole replacement activities will be immediately reported to the Development Services Division. Any risks to Wellhead Protection Zones associated with the project will be mitigated prior to recommencing any activities based upon supplemental recommendations or reports by the January 11, 2018 | Page 12 File No. 0186-871-06 applicant’s geotechnical professional. Weekly on-site inspections and reports documenting erosion control measures will be completed by the applicant. LIMITATIONS We have prepared this report for the exclusive use of PSE and their authorized agents for the Energize Eastside project located in Renton, Washington. The purpose of our services was to review slope stability impacts in relation to vegetation management and tree removal in erosion, steep slope, landslide and coal mine hazard areas along the transmission line corridor within the City of Renton. Impacts to slope stability for pile installation was evaluated in a separate report. Where appropriate, information from the previous reports have been used in developing our recommendations and comments presented in this report. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. REFERENCES Booth, D.B., and Wisher, A. P., compilers, Geologic map of King County, Washington Pacific Northwest Center for Geologic Mapping Studies: scale 1:100,000, 2006. Available at http://geomapnw.ess.washington.edu/services/publications/map/data/KingCo_composite.pdf). Burroughs, E.R. Jr, and Thomas, B.R., 1977, “Declining root strength in Douglas-fir after felling as a factor in slope stability.” Research Paper INT-90, Ogden, Utah, U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station, 27 p. City of Renton, COR Maps (http://rp.rentonwa.gov/SilverlightPublic/Viewer.html?Viewer=COR-Maps). City of Renton, Municipal Code (http://www.codepublishing.com/wa/renton/): Title IV, Ch. 3, 4-3-050, and Renton Ordinance 5137, Section II, part J. City of Renton, Sensitive Areas Steep Slopes Map (http://rentonwa.gov/uploadedFiles/Government/FIT/GIS/PDF_Files/SteepSlopes.pdf). GeoEngineers, Inc. December 19, 2014. Geologic Hazards Evaluation and Preliminary Geotechnical Engineering Services, File No. 0186-871-02. Prepared for Puget Sound Energy. King County iMap (http://gismaps.kingcounty.gov/iMap/?center=- 13600520%2C6025590&scale=2256.994353&) Accessed June 30, 2017. NRCS, National Resource Conservation Service Web Based Soil Survey, 2008. http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx. Washington Division of Geology and Earth Resources, Digital Report 2, Digital Geologic Maps of the 1:100,000 Quadrangles of Washington. January 11, 2018 | Page 13 File No. 0186-871-06 Ziemer, R. R., 1981a, “Roots and stability of forested slopes” in “International Symposium on erosion and sediment transport in Pacific rim steep lands,” 1981 January 25-31; Christchurch, New Zealand. IAHS Publication 132 International Association of Hydrologic Sciences Press, Washington, D.C., pp. 341 – 361. Ziemer, R. R., 1981b, “The role of vegetation in the stability of forested slopes” in “Proceedings, International Union of Forestry Research Organizations XVII World Conference,” September 6-17, 1981, Kyoto, Japan. IUFRO Congress Council, pp 297-308. Have we delivered World Class Client Service? Please let us know by visiting www.geoengineers.com/feedback. A P P E N D I X F Riverview Park Mitigation Plan SH S S SS S S S APPROXIMATE PARCEL BOUNDARY PSE EASEMENTS EASEMENT CENTERLINE RIVER / STREAM EDGE OF WATER (APPROX.) APPROXIMATE WETLAND BOUNDARY MITIGATION AREA (APPROX. 8,100 SF) EXISTING TREES (TO RETAIN) TREES TO BE SNAGGED (8) TREES TO BE HINGE CUT(1) S H TREES COMMON NAME / BOTANICAL NAME CONT SPACING QTY BIG LEAF MAPLE / ACER MACROPHYLLUM 2 GALLON AS SHOWN 15 IN PLANS WESTERN RED CEDAR / THUJA PLICATA 2 GALLON -20 VINE MAPLE / ACER CIRCINATUM 2 GALLON -15 SHRUB AREAS COMMON NAME / BOTANICAL NAME CONT SPACING QTY PACIFIC NINEBARK / PHYSOCARPUS CAPITATUS1 GALLON 48" o.c.85 NOOTKA ROSE / ROSA NUTKANA 1 GALLON 48" o.c.85 SALMONBERRY / RUBUS SPECTABILIS 1 GALLON 48" o.c.85 LIVE STAKES COMMON NAME / BOTANICAL NAME CONT SPACING QTY BLACK COTTONWOOD / POPULUS BALAMIFERALIVE STAKE 12" o.c.75 RED TWIG DOGWOOD / CORNUS SERICEA LIVE STAKE 12" o.c.75 PACIFIC WILLOW / SALIX LUCIDA LIVE STAKE 12" o.c.75 SITKA WILLOW / SALIX SITCHENSIS LIVE STAKE 12" o.c.75 RENTON RIVERVIEW PARK CANDIDATE PLANT SCHEDULE UPLANDSHRUB AREAS COMMON NAME / BOTANICAL NAME CONT SPACING QTY OEMLARIA CERASIFORMIS / OSOBERRY 1 GALLON 72" o.c.120 NOOTKA ROSE / ROSA NUTKANA 1 GALLON 48" o.c.140 SYMPHORICARPUS ALBUS / SNOWBERRY 1 GALLON 48" o.c.140 RIVERVIEW PARK 80'20'10'0 40'MITIGATION PLAN LEGEND 100' PSE EA S E M E N T NOTES 1.PLEASE BE AWARE THAT CONSTRUCTION ACCESS, POLE TYPES, POLE HEIGHTS, AND POLE LOCATIONS ARE SUBJECT TO CHANGE PENDING FURTHER DESIGN, ENVIRONMENTAL REVIEW, PERMITTING AND IN-FIELD CONSTRUCTION NEEDS. 2.WETLAND WAS DELINEATED BY THE WATERSHED COMPANY ON 9-29-2017 USING GPS. GPS DATA DISPLAYED ON THIS MAP WAS COLLECTED IN THE FIELD USING A TRIMBLE GEOXH HAND HELD UNIT. THE DATA WAS DIFFERENTIALLY CORRECTED USING TRIMBLE PATHFINDER OFFICE SOFTWARE TO FURTHER INCREASE POSITION ACCURACY. GPS DATA IS BELIEVED RELIABLE FOR GENERAL PLANNING AND MOST REGULATORY PURPOSES. HOWEVER, ACCURACY IS VARIABLE AND SHOULD NOT BE CONSIDERED EQUIVALENT TO A PROFESSIONAL LAND SURVEY. NO WARRANTY IS EXPRESSED OR IMPLIED. 3.DUE TO LIMITATIONS ON GPS ACCURACY, WETLAND LOCATION SHOWN IS APPROXIMATE. ECOLOGIST OR QUALIFIED PROFESSIONAL SHALL MARK EXTENTS OF WETLAND AND STREAM IN FIELD. PERMIT SET NOT FOR CONSTRUCTION CEDAR RI V E R W1 VICINITY MAP PROJECT LOCATION SHEET INDEX 1. MITIGATION PLAN 2. LANDSCAPE CONSTRUCTION DETAILS 3. PLANT INSTALLATION AND MITIGATION NOTES 4. MITIGATION NOTES (CONTINUED) TREE INDEX 50' PSE EAS E M E N T CEDAR RIVER TRAIL EASEMENT 3182413 EASEMENT 3351623 HINGE CUT SNAG POND UNDEFINED CHANNEL WETLAND NR02 W2 2 W2 1 PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED: SHEET SIZE: ORIGINAL PLAN IS 22" x 34". SCALE ACCORDINGLY.BY© Copyright- The Watershed Company DATEPRINTED BYFILENAMETHE WATERSHED COMPANY S c i e n c e & D e s i g n 750 Sixth Street South Kirkland WA 98033 p 425.822.5242 www.watershedco.com JOB NUMBER: SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.RIVERVIEW PARKMITIGATION PLANPREPARED FOR: PUGET SOUND ENERGYENERGIZE EASTSIDEPARCEL # 162305-9033RENTON, WA 98058JC RH RH MF, JC 111103.11 OF 4112-21-2017MITIGATION PLANRHPARCEL # 162305-9033 TREE TO REMAIN STREAM NR02 MITIGATIONAREA W2 3, 4 W2 5 LIVE STAKES W2 5 W2 5 NOTES:1.SEE PLAN FOR LOCATION. VERIFY FALL DIRECTION IN FIELD WITH ASSISTANCE FROM THE RESTORATION CONSULTANT.2.TREE SHALL HAVE PLIABLE WOOD AND A MAXIMUM DBH OF 15 INCHES.4.USING ONLY A BACK CUT THAT DOES NOT FULLY SEVER THE TREE’S TRUNK FROM THE STUMP, LEAVE THE FALLEN TREECONNECTED TO THE STUMP BY A “HINGE” OF BARK.5.THE LENGTH OF THE HINGE SHOULD BE 80% OF THE DBH. VERIFY WITH RESTORATION CONSULTANT BASED ON SPECIES.6.FOR LARGER DBH TREES, PENETRATE TRUNK WITH A VERTICAL PLUNGE CUT PRIOR TO HORIZONTAL BACK CUT, OR MAKE ASHALLOW NOTCH, 1-2 INCHES DEEP, ON THE SIDE OF THE TREE FACING ITS FALL DIRECTION. HORIZONTAL BACK-CUTAT HEIGHT BETWEENTHREE AND SIX FEETABOVE GROUND LINE. PUSH TREE OVEROR PULL TRUNKTOWARD CHOSENFALL DIRECTION,AND LEAVEATTACHED TOHINGE. PLUNGE CUT AND/ORNOTCH WHENAPPROPRIATE. SEENOTES BELOW. EXISTING CONDITION STEP ONE STEP TWO 15" DBH 12" WIDE HINGE(80% OF DBH) BACK CUTHINGE OPTIONAL NOTCH PLAN VIEW OF CUT HINGE-FELLED TREESSHALL BE VERIFIED BYTHE RESTORATIONSPECIALIST. SNAG NOTES:SEE TREE SNAG TABLE FOR TREES WHICH ARE TO BERETAINED AS SNAGS. ALL TREES SHOULD BE: 1.SNAGS ON SITE ARE TO BE TOPPED BY CLIMBINGARBORIST TO HEIGHT AS INDIVIDUALLY CONFIRMEDON TREE INDEX TABLE.2.ONCE TOP HAS BEEN REMOVED ARBORIST IS TOMAKE A CORONET CUT TO GIVE A NATURAL BREAKAPPEARANCE.3.HABITAT BOXES ARE TO BE MOUNTED TO A MINIMUMOF 12' FROM THE GROUND.4.RETAIN ALL BRANCHES FOR PERCHES AND HABITATSTRUCTURES- DO NOT LIMB.5.LIVE TREES SHOULD BE DEADENED BY CUTTINGTWO 6” WIDE, ANGLED BANDS AROUND THE BASE OFTHE TREE WITH AN AXE OR BY MAKING TWO CUTSAROUND THE TREE WITH A CHAIN SAW TO A DEPTHOF APPROXIMATELY 1 INCH BELOW THE BARKLAYER. GIRDLE CUT HABITAT BOX OR CAVITYHEIGHT VARIES ALL LIMBS REMAIN UPWARD BAT SLITS.MIN. 13'-0" SNAG HEIGHT, CORONET CUTOR MACHINE BREAK GROUND 6" 3' - 5' BAT ROOSTING SLIT NOTES1.TO MAKE BAT ROOSTING CUTS, BEGINAPPROXIMATELY 3'-0" BELOW CORONET CUT ATTOP OF SNAG. AT AN ANGLE OF 80 DEGREES TOTHE GROUND, CUT INTO TREE TRUNK WITH ANUPWARD SLANT. MAKE 3 PARALLEL CUTS,APPROXIMATELY 2'-0" DEEP.2.FACE OF BAT ROOST SLITS ARE TO FACE EASTOR SOUTH DEPENDING ON AVAILABILITY OFSUNLIGHT IN THE MORNING HOURS.3.TO DETER SPECIES SUCH AS WASPS FROMINHABITING ROOST AREAS IT IS RECOMMENDEDTHAT CUTS BE MADE TO A THICKNESS OF 3/4". 80° NOTES:1.INSTALL HARDWOOD CUTTINGS DURING THEIR DORMANCY. DONOT ALLOW THEM TO DRY OUT. 2.CUTTINGS SHALL BE 34" TO 1" IN DIAMETER OR APPROVEDEQUIVALENT.3.INSTALL TO MIN. 2/3RDS DEPTH INTO SOIL. USE TRIANGULARSPACING. SEE PLANTING SCHEDULE FOR SPACING.4.INSURE THAT BUDS ARE POINTING UP.5.FIRM UP SOIL AROUND INSTALLED CUTTING.6.WATER AFTER PLANTING AND BEFORE MULCHING. SOIL AMENDMENTS ASSPECIFIED FORM PILOT HOLE W/ ROCKBAR, REBAR OR OTHERPLANTING TOOL. DO NOTHAMMER OR POUND INCUTTINGS UNLESS APPROVEDBY RESTORATION SPECIALIST. TAMP SOIL AROUND CUTTING,ENSURE NO AIR POCKETS 1/3RDCUTTINGHT.2/3RDSCUTTINGHT.SEE PLANTING SCHEDULEFOR MIN. LENGTHANGLE CUT AT BASE MINIMUM TWO LIVE BUDSEXPOSED ABOVE GROUND. FINISH GRADE SPECIFIED MULCH LAYER NOTES:1. PLANTING PIT SHALL NOT BE LESS THAN (2)TIMES THE WIDTH OF THE ROOT BALL DIA.2. LOOSEN SIDES AND BOTTOMS OF PLANTING PIT3. SOAK PLANTING PIT AFTER PLANTING 2X MIN DIA. ROOTBALL REMOVE FROM POT OR BURLAP & ROUGH-UPROOT BALL BEFORE INSTALLING. UNTANGLEAND STRAIGHTEN CIRCLING ROOTS - PRUNE IFNECESSARY. IF PLANT IS EXCEPTIONALLYROOT-BOUND, DO NOT PLANT AND RETURN TONURSERY FOR AN ACCEPTABLE ALTERNATIVE SPECIFIED MULCH LAYER. HOLD BACK MULCHFROM TRUNK/STEMS FINISH GRADE REMOVE DEBRIS AND LARGE ROCKS FROM PLANTINGPIT AND SCARIFY SIDES AND BASE. BACKFILL WITHSPECIFIED SOIL. FIRM UP SOIL AROUND PLANT. P L A N WILLOW STAKES OHWM SHRUB PLANTING AREA CHANNEL 1'-0"TYP. RIVERVIEW PARK LANDSCAPE CONSTRUCTION DETAILS PERMIT SET NOT FOR CONSTRUCTION LIVE STAKE SPACING SCALE: NTSW2 3 W2 SCALE: NTSW2 4 LIVE STAKE PLANTING HINGE CUT TREE SCALE: NTSW2 1 STANDING SNAG SCALE: NTSW2 2 CONTAINER PLANTING SCALE: NTSW2 5 PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED: SHEET SIZE: ORIGINAL PLAN IS 22" x 34". SCALE ACCORDINGLY.BY© Copyright- The Watershed Company DATEPRINTED BYFILENAMETHE WATERSHED COMPANY S c i e n c e & D e s i g n 750 Sixth Street South Kirkland WA 98033 p 425.822.5242 www.watershedco.com JOB NUMBER: SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.RIVERVIEW PARKMITIGATION PLANPREPARED FOR: PUGET SOUND ENERGYENERGIZE EASTSIDEPARCEL # 162305-9033RENTON, WA 98058JC RH RH MF, JC 111103.11 OF 4112-21-2017MITIGATION PLANRH PERMIT SET NOT FOR CONSTRUCTION W3 GENERAL NOTES QUALITY ASSURANCE 1. PLANTS SHALL MEET OR EXCEED THE SPECIFICATIONS OF FEDERAL, STATE, AND LOCAL LAWS REQUIRING INSPECTION FOR PLANT DISEASE AND INSECT CONTROL. 2. PLANTS SHALL BE HEALTHY, VIGOROUS, AND WELL-FORMED, WITH WELL DEVELOPED, FIBROUS ROOT SYSTEMS, FREE FROM DEAD BRANCHES OR ROOTS. PLANTS SHALL BE FREE FROM DAMAGE CAUSED BY TEMPERATURE EXTREMES, LACK OR EXCESS OF MOISTURE, INSECTS, DISEASE, AND MECHANICAL INJURY. PLANTS IN LEAF SHALL BE WELL FOLIATED AND OF GOOD COLOR. PLANTS SHALL BE HABITUATED TO THE OUTDOOR ENVIRONMENTAL CONDITIONS INTO WHICH THEY WILL BE PLANTED (HARDENED-OFF). 3. TREES WITH DAMAGED, CROOKED, MULTIPLE OR BROKEN LEADERS WILL BE REJECTED. WOODY PLANTS WITH ABRASIONS OF THE BARK OR SUN SCALD WILL BE REJECTED. 4. NOMENCLATURE: PLANT NAMES SHALL CONFORM TO FLORA OF THE PACIFIC NORTHWEST BY HITCHCOCK AND CRONQUIST, UNIVERSITY OF WASHINGTON PRESS, 1973 AND/OR TO A FIELD GUIDE TO THE COMMON WETLAND PLANTS OF WESTERN WASHINGTON & NORTHWESTERN OREGON, ED. SARAH SPEAR COOKE, SEATTLE AUDUBON SOCIETY, 1997. DEFINITIONS 1.PLANTS/PLANT MATERIALS. PLANTS AND PLANT MATERIALS SHALL INCLUDE ANY LIVE PLANT MATERIAL USED ON THE PROJECT. THIS INCLUDES BUT IS NOT LIMITED TO CONTAINER GROWN, B&B OR BAREROOT PLANTS; LIVE STAKES AND FASCINES (WATTLES); TUBERS, CORMS, BULBS, ETC..; SPRIGS, PLUGS, AND LINERS. 2.CONTAINER GROWN. CONTAINER GROWN PLANTS ARE THOSE WHOSE ROOTBALLS ARE ENCLOSED IN A POT OR BAG IN WHICH THAT PLANT GREW. SUBSTITUTIONS 1. IT IS THE CONTRACTOR'S RESPONSIBILITY TO OBTAIN SPECIFIED MATERIALS IN ADVANCE IF SPECIAL GROWING, MARKETING OR OTHER ARRANGEMENTS MUST BE MADE IN ORDER TO SUPPLY SPECIFIED MATERIALS. 2. SUBSTITUTION OF PLANT MATERIALS NOT ON THE PROJECT LIST WILL NOT BE PERMITTED UNLESS AUTHORIZED IN WRITING BY THE RESTORATION CONSULTANT. 3. IF PROOF IS SUBMITTED THAT ANY PLANT MATERIAL SPECIFIED IS NOT OBTAINABLE, A PROPOSAL WILL BE CONSIDERED FOR USE OF THE NEAREST EQUIVALENT SIZE OR ALTERNATIVE SPECIES, WITH CORRESPONDING ADJUSTMENT OF CONTRACT PRICE. 4. SUCH PROOF WILL BE SUBSTANTIATED AND SUBMITTED IN WRITING TO THE CONSULTANT AT LEAST 30 DAYS PRIOR TO START OF WORK UNDER THIS SECTION. INSPECTION 1. PLANTS SHALL BE SUBJECT TO INSPECTION AND APPROVAL BY THE RESTORATION CONSULTANT FOR CONFORMANCE TO SPECIFICATIONS, EITHER AT TIME OF DELIVERY ON-SITE OR AT THE GROWER'S NURSERY. APPROVAL OF PLANT MATERIALS AT ANY TIME SHALL NOT IMPAIR THE SUBSEQUENT RIGHT OF INSPECTION AND REJECTION DURING PROGRESS OF THE WORK. 2. PLANTS INSPECTED ON SITE AND REJECTED FOR NOT MEETING SPECIFICATIONS MUST BE REMOVED IMMEDIATELY FROM SITE OR RED-TAGGED AND REMOVED AS SOON AS POSSIBLE. 3. THE RESTORATION CONSULTANT MAY ELECT TO INSPECT PLANT MATERIALS AT THE PLACE OF GROWTH. AFTER INSPECTION AND ACCEPTANCE, THE RESTORATION CONSULTANT MAY REQUIRE THE INSPECTED PLANTS BE LABELED AND RESERVED FOR PROJECT. SUBSTITUTION OF THESE PLANTS WITH OTHER INDIVIDUALS, EVEN OF THE SAME SPECIES AND SIZE, IS UNACCEPTABLE. MEASUREMENT OF PLANTS 1. PLANTS SHALL CONFORM TO SIZES SPECIFIED UNLESS SUBSTITUTIONS ARE MADE AS OUTLINED IN THIS CONTRACT. 2. HEIGHT AND SPREAD DIMENSIONS SPECIFIED REFER TO MAIN BODY OF PLANT AND NOT BRANCH OR ROOT TIP TO TIP. PLANT DIMENSIONS SHALL BE MEASURED WHEN THEIR BRANCHES OR ROOTS ARE IN THEIR NORMAL POSITION. 3. WHERE A RANGE OF SIZE IS GIVEN, NO PLANT SHALL BE LESS THAN THE MINIMUM SIZE AND AT LEAST 50% OF THE PLANTS SHALL BE AS LARGE AS THE MEDIAN OF THE SIZE RANGE. (EXAMPLE: IF THE SIZE RANGE IS 12" TO 18", AT LEAST 50% OF PLANTS MUST BE 15" TALL.). SUBMITTALS PROPOSED PLANT SOURCES 1. WITHIN 45 DAYS AFTER AWARD OF THE CONTRACT, SUBMIT A COMPLETE LIST OF PLANT MATERIALS PROPOSED TO BE PROVIDED DEMONSTRATING CONFORMANCE WITH THE REQUIREMENTS SPECIFIED. INCLUDE THE NAMES AND ADDRESSES OF ALL GROWERS AND NURSERIES. PRODUCT CERTIFICATES 1. PLANT MATERIALS LIST - SUBMIT DOCUMENTATION TO CONSULTANT AT LEAST 30 DAYS PRIOR TO START OF WORK UNDER THIS SECTION THAT PLANT MATERIALS HAVE BEEN ORDERED. ARRANGE PROCEDURE FOR INSPECTION OF PLANT MATERIAL WITH CONSULTANT AT TIME OF SUBMISSION. 2. HAVE COPIES OF VENDOR'S OR GROWERS' INVOICES OR PACKING SLIPS FOR ALL PLANTS ON SITE DURING INSTALLATION. INVOICE OR PACKING SLIP SHOULD LIST SPECIES BY SCIENTIFIC NAME, QUANTITY, AND DATE DELIVERED (AND GENETIC ORIGIN IF THAT INFORMATION WAS PREVIOUSLY REQUESTED). DELIVERY, HANDLING, & STORAGE NOTIFICATION CONTRACTOR MUST NOTIFY CONSULTANT 48 HOURS OR MORE IN ADVANCE OF DELIVERIES SO THAT CONSULTANT MAY ARRANGE FOR INSPECTION. PLANT MATERIALS 1.TRANSPORTATION - DURING SHIPPING, PLANTS SHALL BE PACKED TO PROVIDE PROTECTION AGAINST CLIMATE EXTREMES, BREAKAGE AND DRYING. PROPER VENTILATION AND PREVENTION OF DAMAGE TO BARK, BRANCHES, AND ROOT SYSTEMS MUST BE ENSURED. 2.SCHEDULING AND STORAGE - PLANTS SHALL BE DELIVERED AS CLOSE TO PLANTING AS POSSIBLE. PLANTS IN STORAGE MUST BE PROTECTED AGAINST ANY CONDITION THAT IS DETRIMENTAL TO THEIR CONTINUED HEALTH AND VIGOR. 3.HANDLING - PLANT MATERIALS SHALL NOT BE HANDLED BY THE TRUNK, LIMBS, OR FOLIAGE BUT ONLY BY THE CONTAINER, BALL, BOX, OR OTHER PROTECTIVE STRUCTURE, EXCEPT BAREROOT PLANTS SHALL BE KEPT IN BUNDLES UNTIL PLANTING AND THEN HANDLED CAREFULLY BY THE TRUNK OR STEM. 4.LABELS - PLANTS SHALL HAVE DURABLE, LEGIBLE LABELS STATING CORRECT SCIENTIFIC NAME AND SIZE. TEN PERCENT OF CONTAINER GROWN PLANTS IN INDIVIDUAL POTS SHALL BE LABELED. PLANTS SUPPLIED IN FLATS, RACKS, BOXES, BAGS, OR BUNDLES SHALL HAVE ONE LABEL PER GROUP. WARRANTY PLANT WARRANTY PLANTS MUST BE GUARANTEED TO BE TRUE TO SCIENTIFIC NAME AND SPECIFIED SIZE, AND TO BE HEALTHY AND CAPABLE OF VIGOROUS GROWTH. REPLACEMENT 1.PLANTS NOT FOUND MEETING ALL OF THE REQUIRED CONDITIONS AT THE CONSULTANT'S DISCRETION MUST BE REMOVED FROM SITE AND REPLACED IMMEDIATELY AT THE CONTRACTOR'S EXPENSE. 2.PLANTS NOT SURVIVING AFTER ONE YEAR TO BE REPLACED AT THE CONTRACTOR'S EXPENSE. PLANT MATERIAL GENERAL 1. PLANTS SHALL BE NURSERY GROWN IN ACCORDANCE WITH GOOD HORTICULTURAL PRACTICES UNDER CLIMATIC CONDITIONS SIMILAR TO OR MORE SEVERE THAN THOSE OF THE PROJECT SITE. 2. PLANTS SHALL BE TRUE TO SPECIES AND VARIETY OR SUBSPECIES. NO CULTIVARS OR NAMED VARIETIES SHALL BE USED UNLESS SPECIFIED AS SUCH. QUANTITIES SEE PLANT LIST ON ACCOMPANYING PLANS AND PLANT SCHEDULES. ROOT TREATMENT 1.CONTAINER GROWN PLANTS (INCLUDES PLUGS): PLANT ROOT BALLS MUST HOLD TOGETHER WHEN THE PLANT IS REMOVED FROM THE POT, EXCEPT THAT A SMALL AMOUNT OF LOOSE SOIL MAY BE ON THE TOP OF THE ROOTBALL. 2.PLANTS MUST NOT BE ROOT-BOUND; THERE MUST BE NO CIRCLING ROOTS PRESENT IN ANY PLANT INSPECTED. 3.ROOTBALLS THAT HAVE CRACKED OR BROKEN WHEN REMOVED FROM THE CONTAINER SHALL BE REJECTED. PLANT INSTALLATION SPECIFICATIONS MITIGATION NOTES RIVERVIEW PARK MITIGATION PLAN PSE ENERGIZE EASTSIDE 230 - RENTON EXECUTIVE SUMMARY PSE'S ENERGIZE EASTSIDE PROJECT (THE PROJECT) PROPOSES TO UPGRADE EXISTING TRANSMISSION LINES IN RENTON IN ORDER TO INCREASE TRANSMISSION SYSTEM CAPACITY TO 230KV POWER. PROJECT ELEMENTS, EXISTING CONDITIONS, MITIGATION SEQUENCING, AND PROJECT IMPACTS TO CRITICAL AREAS ARE DISCUSSED IN THE CITY OF RENTON CRITICAL AREAS REPORT (RENTON CAR) PREPARED BY THE WATERSHED COMPANY, DECEMBER 2017. THIS MITIGATION PLAN IS INTENDED TO REPRESENT THE MITIGATION PLAN REFERENCED IN THE RENTON CAR. IT HAS BEEN DESIGNED TO APPROPRIATELY MITIGATE FOR PROJECT IMPACTS OCCURRING IN WETLAND AND STREAM CRITICAL AREA BUFFERS AS DESCRIBED IN THE RENTON CAR AND REQUIRED BY THE RENTON MUNICIPAL CODE (RMC). PROPOSED PROJECT ACTIVITIES WITHIN THE LOWER CEDAR RIVER SUBBASIN IMPACT WETLAND AND STREAM BUFFERS IN THREE POSSIBLE WAYS: PERMANENT IMPACTS RESULTING IN A CONVERSION TO A DEVELOPED CONDITION AS A RESULT OF POLE FOOTPRINTS, VEGETATION CONVERSION FROM A FORESTED VEGETATION TYPE TO A SHRUB OR HERBACEOUS COMMUNITY DUE TO VEGETATION MANAGEMENT REQUIREMENTS (CONVERSION), AND/OR TEMPORARY IMPACTS ASSOCIATED WITH CONSTRUCTION ACTIVITIES (TEMPORARY). TEMPORARY IMPACTS WILL BE RESTORED IN PLACE AFTER CONSTRUCTION WORK IS COMPLETE. CONVERSION AND PERMANENT BUFFER IMPACTS REQUIRE MITIGATION WHICH IS PRESENTED HEREIN. THE PROJECT HAS AVOIDED ALL DIRECT PERMANENT IMPACTS (FILL) TO WETLANDS, STREAMS AND STREAM BUFFERS. ONE NEW POLE WILL BE INSTALLED WITHIN A WETLAND BUFFER AND THREE REPLACEMENT POLES WILL BE INSTALLED IN THE SAME LOCATION AS EXISTING POLES WITHIN A WETLAND BUFFER, BUT WITH A LARGER FOOTPRINT. TWO EXISTING TRANSMISSION POLES WILL BE REMOVED FROM WETLAND BUFFER, RESULTING IN AN OVERALL NET INCREASE OF ONLY 68 SF OF FILL MATERIAL IN BUFFER AREAS. VEGETATION CONVERSION (TREE REMOVAL) IMPACTS OCCUR IN THE BUFFER AREA OF THREE WETLAND AND TWO STREAM FEATURES AND ARE NECESSARY TO ACCOMMODATE THE NEW 230KV TRANSMISSION LINE DESIGN AND MEET FEDERAL SAFETY STANDARDS (SEE TABLE BELOW). MITIGATION FOR IMPACTS, PRESENTED IN THE TABLE ABOVE, ARE PLANNED IN WETLAND NRO2 AND THE ADJACENT OVERLAPPING WETLAND AND STREAM BUFFER. AS DISCUSSED IN THE RENTON CAR, THIS LOCATION WAS SELECTED FOR MITIGATION ACTIVITIES BASED UPON THE LOCATION OF PROJECT IMPACTS, OPPORTUNITY PRESENT, PROPERTY OWNERSHIP, PROXIMITY TO OTHER REGULATED CRITICAL AREAS, AND THE VALUE OF THE ENHANCMENT TO OVERALL CRITICAL AREA FUNCTION IN THE CORRIDOR. THE MINIMUM MITIGATION AREA REQUIRED, AS PRESENTED IN THE RENTON CAR IS 8,042 SF. THIS WAS CALCULATED BASED ON A PERMANENT IMPACT MITIGATION RATIO OF 1:1 AND A VEGETATION CONVERSION MITIGATION RATIO OF 0.5:1 BASED ON ECOLOGY GUIDANCE. A TOTAL AREA OF APPROXIMATELY 8,100 SF OF WETLAND AND BUFFER WILL BE ENHANCED. THE ENHANCEMENT AREAS INCLUDE INVASIVE SPECIES REMOVAL AND INSTALLATION OF NATIVE TREES AND SHRUBS. OVERVIEW THE MITIGATION PLAN CONSISTS OF APPROXIMATELY 8,100 SF OF WETLAND AND BUFFER ENHANCEMENT. THE MITIGATION PLAN INCLUDES A COMPREHENSIVE FIVE-YEAR MAINTENANCE AND MONITORING PLAN, PER RMC 4-3-50.L.3. THE PLAN SPECIFIES APPROPRIATE SPECIES FOR PLANTING AND PLANTING TECHNIQUES, DESCRIBES PROPER MAINTENANCE ACTIVITIES, AND SETS FORTH PERFORMANCE STANDARDS TO BE MET YEARLY DURING MONITORING. THESE SPECIFICATIONS AND STANDARDS WILL ENSURE THAT ENHANCEMENT/RESTORATION PLANTINGS WILL BE MAINTAINED, MONITORED, AND SUCCESSFULLY ESTABLISHED WITHIN THE FIRST FIVE YEARS FOLLOWING IMPLEMENTATION. BUFFER AND WETLAND ENHANCEMENT WILL INCLUDE INSTALLATION OF A NATIVE SHRUB AND TREE AREA AND A LIVE STAKE PLANTING AREA ALONG THE UNDEFINED CHANNEL IDENTIFIED WITHIN WETLAND NRO2. IN ADDITION TO NATIVE PLANTINGS, BUFFER ENHANCEMENT WILL INCLUDE CREATION OF 8 HABITAT SNAGS AND 1 HINGE-CUT TREE FROM TREES ASSESSED TO BE DEAD OR DYING. THESE MITIGATION ACTIVITIES ARE INTENDED TO INCREASE NATIVE PLANT COVER, DECREASE INVASIVE SPECIES PREVALENCE, IMPROVE NATIVE SPECIES DIVERSITY, AND PROVIDE FOOD AND OTHER HABITAT RESOURCES FOR WILDLIFE. GOALS 1.ENHANCE DEGRADED WETLAND AND BUFFER IN THE VICINTIY OF THE CEDAR RIVER. a.ESTABLISH DENSE AND DIVERSE VEGETATION COMMUNITIES THROUGHOUT THE MITIGATION AREA b.INCREASE SPECIAL HABITAT FEATURES IN BUFFER AREAS THROUGH CREATION OF HABITAT SNAGS AND HINGE-CUT TREES. PERFORMANCE STANDARDS THE STANDARDS LISTED BELOW WILL BE USED TO JUDGE THE SUCCESS OF THE PLAN OVER TIME. IF THE STANDARDS ARE MET AT THE END OF THE FIVE-YEAR MONITORING PERIOD, THE CITY SHALL RELEASE THE PERFORMANCE BOND. SHRUB MIX AREAS 1.SURVIVAL: a.100% SURVIVAL OF ALL INSTALLED WOODY VEGETATION AT THE END OF YEAR 1, STARTING FROM THE DATE OF SUBSTANTIALLY COMPLETE INSTALLATION. THIS STANDARD MAY BE MET THROUGH ESTABLISHMENT OF INSTALLED PLANTS OR BY REPLANTING AS NECESSARY TO ACHIEVE THE REQUIRED NUMBERS. b.80% SURVIVAL OF ALL INSTALLED WOODY VEGETATION AT THE END OF YEAR 2. THIS STANDARD MAY BE MET THROUGH ESTABLISHMENT OF INSTALLED PLANTS OR BY REPLANTING AS NECESSARY TO ACHIEVE THE REQUIRED NUMBERS. i. SURVIVAL BEYOND YEAR 2 IS DIFFICULT TO TRACK. THEREFORE, DIVERSITY AND COVER STANDARDS ARE PROPOSED IN PLACE OF SURVIVAL (SEE BELOW). 2.NATIVE VEGETATION COVER IN PLANTED AREA: a.ACHIEVE AT LEAST 60% COVER OF NATIVE SHRUBS BY THE END OF YEAR 3. TRANSMISSION LINE-FRIENDLY NATIVE VOLUNTEER SPECIES MAY COUNT TOWARD THIS STANDARD. b.ACHIEVE AT LEAST 80% COVER OF NATIVE SHRUBS BY THE END OF YEAR 5. TRANSMISSION LINE-FRIENDLY NATIVE VOLUNTEER SPECIES MAY COUNT TOWARD THIS STANDARD. 3.SPECIES DIVERSITY IN PLANTED AREAS: a.ESTABLISH AT LEAST FOUR NATIVE SHRUB SPECIES, BY YEAR 5. TRANSMISSION LINE-FRIENDLY NATIVE VOLUNTEER SPECIES MAY COUNT TOWARD THIS STANDARD. “ESTABLISHMENT” IS CONSIDERED TO BE AT LEAST FOUR HEALTHY, INDIVIDUAL PLANTS OF A GIVEN SPECIES PRESENT WITHIN THE MITIGATION AREAS. 4.INVASIVE SPECIES STANDARD: NO MORE THAN 20% COVER OF INVASIVE SPECIES IN THE PLANTING AREA IN ANY MONITORING YEAR, EXCEPT SHALL NOT EXCEED 10% COVER AT THE END OF YEAR 5. INVASIVE SPECIES ARE DEFINED AS ANY CLASS A, B, OR C NOXIOUS WEEDS AS LISTED BY THE KING COUNTY NOXIOUS WEED CONTROL BOARD. RIVERVIEW PARK PLANT INSTALLATION AND MITIGATION NOTES PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED: SHEET SIZE: ORIGINAL PLAN IS 22" x 34". SCALE ACCORDINGLY.BY© Copyright- The Watershed Company DATEPRINTED BYFILENAMETHE WATERSHED COMPANY S c i e n c e & D e s i g n 750 Sixth Street South Kirkland WA 98033 p 425.822.5242 www.watershedco.com JOB NUMBER: SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.RIVERVIEW PARKMITIGATION PLANPREPARED FOR: PUGET SOUND ENERGYENERGIZE EASTSIDEPARCEL # 162305-9033RENTON, WA 98058JC RH RH MF, JC 111103.11 OF 4112-21-2017MITIGATION PLANRH RIVERVIEW PARK MITIGATION NOTES (CONTINUED) RIVERVIEW PARK MITIGATION NOTES HABITAT FEATURES 1.MAINTAIN/RETAIN CREATED SNAGS AND HINGE-CUT TREES IN MITIGATION AREAS AS SPECIFIED IN THE PLANS FOR THE DURATION OF THE MAINTENANCE AND MONITORING PERIOD. MONITORING METHODS THIS MONITORING PROGRAM IS DESIGNED TO TRACK THE SUCCESS OF THE MITIGATION SITE OVER TIME BY MEASURING THE DEGREE TO WHICH THE PERFORMANCE STANDARDS LISTED ABOVE ARE BEING MET. A FIVE YEAR MONITORING PERIOD IS PROPOSED, CONSISTENT WITH THE METHODS OUTLINED IN RMC 4-3-50.L.3. PER RMC 4-3-50.L.3, SHOULD THE MITIGATION PROJECT FAIL TO MEET ESTABLISHED SUCCESS CRITERIA AT ANY POINT, THE MONITORING PERIOD SHALL BE STARTED OVER AT YEAR ONE. THE ADMINISTRATOR SHALL HAVE THE AUTHORITY TO MODIFY OR EXTEND THE MONITORING PERIOD AND REQUIRE ADDITIONAL MONITORING REPORTS FOR UP TO TEN (10) YEARS WHEN ANY OF THE FOLLOWING CONDITIONS APPLY: A. THE PROJECT DOES NOT MEET THE PERFORMANCE STANDARDS IDENTIFIED IN THE MITIGATION PLAN; B. THE PROJECT DOES NOT PROVIDE ADEQUATE REPLACEMENT FOR THE FUNCTIONS AND VALUES OF THE IMPACTED CRITICAL AREA; C. THE PROJECT INVOLVES ESTABLISHMENT OF FORESTED PLANT COMMUNITIES, WHICH REQUIRE LONGER TIME FOR ESTABLISHMENT. MONITORING OF THE MITIGATION SITE AND ASSOCIATED MONITORING REPORTS WILL BE CONDUCTED/PREPARED BY A RESTORATION SPECIALIST AND SUBMITTED TO THE CITY FOR REVIEW. 1.AN AS-BUILT PLAN AND REPORT WILL BE PREPARED WITHIN 30 DAYS OF SUBSTANTIALLY COMPLETE INSTALLATION OF THE MITIGATION AREA. THE AS-BUILT PLAN WILL DOCUMENT CONFORMANCE WITH THESE PLANS AND WILL DISCLOSE ANY SUBSTITUTIONS OR OTHER NON-CRITICAL DEPARTURES. THE AS-BUILT PLAN WILL ESTABLISH BASELINE PLANT INSTALLATION QUANTITIES, PHOTOPOINTS, MONITORING TRANSECTS, AND SURVEY PLOTS THAT WILL BE USED THROUGHOUT THE MONITORING PERIOD TO MEASURE THE PERFORMANCE STANDARDS. 2.FOR THE FIRST YEAR FOLLOWING INSTALLATION, MONITORING REPORTS SHALL BE SUBMITTED QUARTERLY TO THE CITY. THEREAFTER ANNUAL REPORTS SHALL BE SUBMITTED AT THE END OF THE GROWING SEASON (YEARS 2-5). ANNUAL MONITORING REPORTS WILL INCLUDE THE FOLLOWING INFORMATION: a.SUMMARY OF PREVIOUS/SPRING VISITS. b.PLANT SURVIVAL AND/OR MORTALITY IN MITIGATION AREAS. c.CALCULATION OF NATIVE SPECIES COVER IN SURVEY PLOTS USING THE POINT-FRAME METHOD AND ALONG TRANSECTS USING THE LINE-INTERCEPT METHOD. d.ESTIMATES OF NATIVE SPECIES COVER SITE WIDE. e.INVASIVE SPECIES COVER AT SURVEY PLOTS AND ALONG TRANSECTS AND ESTIMATED SITE WIDE. f.COUNTS OF ESTABLISHED NATIVE SPECIES TO DETERMINE SPECIES RICHNESS. g.PHOTOGRAPHIC DOCUMENTATION AT PERMANENT PHOTOPOINTS. h.INTRUSIONS INTO THE PLANTING AREAS, EROSION, VANDALISM, TRASH, AND OTHER ACTIONS DETRIMENTAL TO THE OVERALL HEALTH OF THE MITIGATION AREAS. i.RECOMMENDATIONS FOR MAINTENANCE IN THE MITIGATION AREAS. j.RECOMMENDATIONS FOR REPLACEMENT OF ALL DEAD OR DYING PLANT MATERIAL WITH SAME OR LIKE SPECIES AND NUMBER AS ON THE APPROVED PLAN. 3.SPRING MONITORING IS RECOMMENDED EARLY IN EACH GROWING SEASON IN YEARS 2 THROUGH 5 TO NOTIFY THE OWNER AND/OR MAINTENANCE CREWS OF NECESSARY EARLY SEASON MAINTENANCE. RECOMMENDATIONS WILL BE ISSUED IN A SPRING MEMO AND WILL NOT BE SUBMITTED TO THE CITY. CONSTRUCTION NOTES AND SPECIFICATIONS GENERAL NOTES THE RESTORATION SPECIALIST WILL OVERSEE THE FOLLOWING: 1.TREE SNAGGING AND HINGE-CUTTING. 2.INVASIVE WEED CLEARING AND SITE PREPARATION; AND 3.PLANT MATERIAL INSPECTION. a.PLANT DELIVERY INSPECTION. b.50% PLANT INSTALLATION/LAYOUT INSPECTION. c.100% PLANT INSTALLATION INSPECTION. WORK SEQUENCE 1.HABITAT FEATURE CREATION: a.SNAG DESIGNATED TREES ACCORDING TO PLAN DETAIL, AND CONSISTENT WITH RECOMMENDATIONS IN THE ASSOCIATED GEOTECHNICAL REPORT. i. TREES SHOULD BE ACCESSED BY FOOT. ii. LARGE DOWNED WOODY DEBRIS SHOULD BE PLACED PERPENDICULAR TO THE SLOPE, OR ROUGHLY PARALLEL TO THE SLOPE CONTOUR, IN A STABLE POSITION. iii. REMAINING TREE DEBRIS SHOULD BE SCATTERED UPSLOPE OF THE BUFFER AREA NEARBY. b.HINGE-CUT DESIGNATED TREES ACCORDING TO PLAN DETAIL (SHEET W2). 2.CLEAR THE PLANTING AREA OF ALL INVASIVE WOODY VEGETATION INCLUDING BUT NOT LIMITED TO HIMALAYAN BLACKBERRY. PULL OTHER HERBACEOUS INVASIVE VEGETATION AS ENCOUNTERED (E.G., REED CANARYGRASS, HERB ROBERT). 3.INSTALL EROSION CONTROLS SUCH AS WATTLES OR JUTE MAT AS DETERMINED NECESSARY IN COORDINATION WITH GEOTECHNICAL CONSULTANT. 4.INSTALL PLANTING AREAS: a.LAYOUT VEGETATION TO BE INSTALLED PER THE PLANTING PLAN AND PLANT SCHEDULE WITH CONSIDERATION OF PLANT SPECIES GROWING CONDITIONS. b.PREPARE A PLANTING PIT FOR EACH PLANT AND INSTALL PER THE PLANTING DETAILS. INSTALL PLANTS DURING DORMANT SEASON (OCTOBER 15TH TO MARCH 15TH). c.MULCH EACH PLANT WITH A CIRCULAR WOOD CHIP MULCH RING, 4 INCHES THICK AND EXTENDING 9 INCHES FROM THE BASE OF THE PLANT (18-INCH DIAMETER). MAINTAIN THREE INCH GAP BETWEEN MULCH AND PLANT STEM. d.SCHEDULE WATERING TRUCK TO PROVIDE AT LEAST ONE INCH OF WATER PER WEEK, AS NECESSARY, FROM JUNE 1ST TO SEPTEMBER 30TH FOR AT LEAST TWO SUMMERS AFTER INITIAL PLANT INSTALLATION. ALTERNATIVE WATERING METHODS (E.G., GATOR BAGS) MAY BE UTILIZED WITH APPROVAL FROM THE RESTORATION SPECIALIST. MAINTENANCE MITIGATION PLAN AREAS SHALL BE MAINTAINED FOR FIVE YEARS FOLLOWING COMPLETION OF THE INITIAL PLANT AND SEED INSTALLATION. 1.ROUTINE MAINTENANCE OF PLANTING AREAS: a.AT LEAST TWICE YEARLY, REMOVE BY HAND ALL COMPETING WEEDS AND WEED ROOTS FROM BENEATH EACH INSTALLED PLANT AND ANY DESIRABLE VOLUNTEER VEGETATION TO A DISTANCE OF 12 INCHES FROM THE MAIN PLANT STEM. WEEDING SHOULD OCCUR AS NEEDED DURING THE SPRING AND SUMMER. FREQUENT WEEDING WILL RESULT IN LOWER MORTALITY AND LOWER PLANT REPLACEMENT COSTS. b.DO NOT WEED THE AREA NEAR THE PLANT BASES WITH STRING TRIMMER (WEED WHACKER). NATIVE WOODY PLANTS ARE EASILY DAMAGED OR KILLED, AND WEEDS EASILY RECOVER AFTER TRIMMING. c.DURING REGULAR WEED MAINTENANCE EFFORTS (FOCUSED AROUND INSTALLED VEGETATION), ALSO GRUB OUT ANY INVASIVE SPECIES PRESENT IN DESIGNATED MITIGATION AREAS AND REMOVE FROM THE SITE. d.APPLY SLOW-RELEASE, PHOSPHOROUS-FREE, GRANULAR FERTILIZER TO EACH INSTALLED PLANT ANNUALLY IN THE SPRING (BY JUNE 1) OF YEARS 2 THROUGH 5. e.MULCH THE WEEDED AREAS BENEATH EACH PLANT WITH WOOD CHIP MULCH AS NECESSARY TO MAINTAIN A MINIMUM 4-INCH-THICK, 18-INCH-DIAMETER MULCH RING. f.ENSURE PLANTS RECEIVE A MINIMUM OF ONE INCH OF WATER PER WEEK, AS NEEDED, FROM JUNE 1ST THROUGH SEPTEMBER 30TH FOR THE FIRST TWO YEARS FOLLOWING INSTALLATION. THE MOST FEASIBLE IRRIGATION OPTION FOR THE SITE IS EXPECTED TO BE USE OF A WATERING TRUCK. IRRIGATION BEYOND THE SECOND YEAR MAY BE NEEDED BASED ON SITE PERFORMANCE OR SIGNIFICANT REPLANTING. g.FOLLOW ADDITIONAL RECOMMENDATIONS NOTED IN THE SPRING OR ANNUAL MONITORING SITE VISIT. h.AS DIRECTED, INSTALL REPLACEMENT PLANTS DURING THE UPCOMING DORMANT SEASON (OCTOBER 15TH TO MARCH 15TH) TO ENSURE AN 80% SURVIVAL RATE. CONTINGENCY PLAN PER RMC 4-3-050.L.2,. A SURETY DEVICE IS REQUIRED TO ENSURE THE APPLICANT'S COMPLIANCE WITH THE TERMS OF THE MITIGATION AGREEMENT. THE DEVICE SHALL MEET THE REQUIREMENTS SET FORTH IN RMC 4-3-050.L.2. MATERIALS 1.BIODEGRADABLE WEED FABRIC: PRODUCT SHALL BE COMPOSED OF 100% BIODEGRADABLE MATERIAL, SHALL BE INTENDED TO SUPRESS WEED GROWTH, AND SHALL FULLY DECOMPOSE IN 1-5 YEARS AFTER INSTALLATION. CONTRACTOR SHALL SUBMIT PRODUCT SPECIFICATION TO THE RESTORATION SPECIALIST FOR APPROVAL PRIOR TO PURCHASE. 2.FERTILIZER: SLOW-RELEASE, GRANULAR, PHOSPHOROUS-FREE FERTILIZER. FOLLOW MANUFACTURER'S INSTRUCTIONS FOR APPLICATION. KEEP FERTILIZER IN A WEATHER-TIGHT CONTAINER WHILE ON SITE. NOTE THAT FERTILIZER IS TO BE APPLIED ONLY IN YEARS 2 THROUGH 5 AND NOT IN THE FIRST YEAR. 3.TOPSOIL: COMMERCIALLY PRODUCED SOIL MIX CONTAINING EQUAL PARTS OF SAND, COMPOST, AND LOAM SOIL. MIX AND QUANTITY TO BE APPROVED BY THE RESTORATION SPECIALIST. 4.RESTORATION SPECIALIST: THE WATERSHED COMPANY [(425) 822-5242] PERSONNEL OR OTHER PERSON QUALIFIED TO EVALUATE ENVIRONMENTAL RESTORATION PROJECTS. 5.WOOD CHIP MULCH: CHIPPED WOODY MATERIAL APPROXIMATELY 1 INCH MINIMUM TO 3 INCHES IN MAXIMUM DIMENSION (NOT SAWDUST OR COARSE HOG FUEL). MULCH SHALL NOT CONTAIN APPRECIABLE QUANTITIES OF GARBAGE, SPILLED OILS OR FUELS, PLASTIC, METAL, SOIL, DIMENSIONAL LUMBER, OR CONSTRUCTION/ DEMOLITION DEBRIS. PACIFIC TOPSOIL [(800) 844-7645] SELLS SUITABLE WOOD CHIP MULCH CALLED “WOOD CHIP MULCH” AT MANY OF THEIR LOCATIONS. NOTE: ARBORIST WOODCHIPS GENERALLY CONTAIN WEED SEEDS AND ARE NOT A RELIABLE ALTERNATIVE. PERMIT SET NOT FOR CONSTRUCTION W4 PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED: SHEET SIZE: ORIGINAL PLAN IS 22" x 34". SCALE ACCORDINGLY.BY© Copyright- The Watershed Company DATEPRINTED BYFILENAMETHE WATERSHED COMPANY S c i e n c e & D e s i g n 750 Sixth Street South Kirkland WA 98033 p 425.822.5242 www.watershedco.com JOB NUMBER: SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.RIVERVIEW PARKMITIGATION PLANPREPARED FOR: PUGET SOUND ENERGYENERGIZE EASTSIDEPARCEL # 162305-9033RENTON, WA 98058JC RH RH MF, JC 111103.11 OF 4112-21-2017MITIGATION PLANRH A P P E N D I X G Honey Dew Creek Conceptual Mitigation Plan S H S S S H1540 1539 1543 1542 1544 1548 1547 1546 1536 1573 1566 1565 1560 1559 1556 1555 1554 1549 1547 1551 1552 1582 1553 1570 1545 1571 1550 1583 1581 PSE EASEMENT BOUNDARY MITIGATION AREA (APPROX. 1,700 SF) EXISTING TREES (TO RETAIN) TREES TO BE SNAGGED (4) TREES TO BE HINGE CUT (2) STREAM BUFFER (115' STANDARD BUFFER, EXTENDED TO TOP OF ADJACENT PROTECTED SLOPES) S H UPLANDSHRUB AREAS COMMON NAME / BOTANICAL NAME CONT SPACING QTY OEMLARIA CERASIFORMIS / OSOBERRY 1 GALLON 72" o.c.- NOOTKA ROSE / ROSA NUTKANA 1 GALLON 48" o.c.- SYMPHORICARPUS ALBUS / SNOWBERRY 1 GALLON 48" o.c.- GROUNDCOVERCOMMON NAME / BOTANICAL NAME CONT SPACING QTY POLYSTICHUM MUNITUM / SWORD FERN 1 GALLON 24" o.c.- MAHONIA NERVOSA / DULL OREGON GRAPE 1 GALLON 24" o.c.- HONEY DEW CREEK 80'20'10'0 40'CONCEPTUAL MITIGATION PLAN LEGEND NOTES 1.PLEASE BE AWARE THAT CONSTRUCTION ACCESS, POLE TYPES, POLE HEIGHTS, AND POLE LOCATIONS ARE SUBJECT TO CHANGE PENDING FURTHER DESIGN, ENVIRONMENTAL REVIEW, PERMITTING AND IN-FIELD CONSTRUCTION NEEDS. 2.PRELIMINARY CONCEPTUAL PLAN, PENDING FIELD VERIFICATION FOR FINAL PLAN. PERMIT SET NOT FOR CONSTRUCTION W1 VICINITY MAP PROJECT LOCATION SHEET INDEX 1. MITIGATION PLAN PROJECT MANAGER: DESIGNED: DRAFTED: CHECKED: SHEET SIZE: ORIGINAL PLAN IS 22" x 34". SCALE ACCORDINGLY.BY© Copyright- The Watershed Company DATEPRINTED BYFILENAMETHE WATERSHED COMPANY S c i e n c e & D e s i g n 750 Sixth Street South Kirkland WA 98033 p 425.822.5242 www.watershedco.com JOB NUMBER: SHEET NUMBER:SUBMITTALS & REVISIONSDESCRIPTIONDATENO.CONCEPTUAL HONEY DEW CREEKMITIGATION PLANPREPARED FOR: PUGET SOUND ENERGYENERGIZE EASTSIDEPARCEL #0423059035, -9342RENTON, WA 98058JC LM LM JC 111103.11 OF 1101-16-2018CONCEPTUAL MITIGATION PLANLMPLANTING SCHEDULE H O N E Y D E W C R E E K HEAVY VEGETATION - BLACKBERRIESAPPROXIMATE TREE LINE Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | Appendix C – Wellhead Protection Areas 36,112 3,009 This map is a user generated static output from an Internet mapping site andis for reference only. Data layers that appear on this map may or may not beaccurate, current, or otherwise reliable. None 4/27/2018 Legend 2,0460 1,023 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 2,046 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Wellhead Protection Area Zones Zone 1 Zone 1 Modified Zone 2 Streams (Classified) Type S Type F Type Np Type Ns Water Service Areas Wastewater Service Areas PSE 115kv PSE 230kv Substations Special Assessment Districts Renton Well Head Protection Map Technical Information Report PSE Energize Eastside – Renton Segment | December 29, 2020 Appendix D – Bond Quantities Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200••Section I: Project Information•••Section II: Bond Quantities Worksheets••Section II.a EROSION CONTROL (Stabilization/Erosion Sediment Control (ESC))•Section II.b TRANSPORTATION (Street and Site Improvements)•Section II.c DRAINAGE (Drainage and Stormwater Facilities): •Section II.d WATER ‐ ONLY APPLICABLE IF WATER SERVICE IS PROVIDED BY CITY OF RENTON•Section II.e SANITARY SEWER ‐ ONLY APPLICABLE IF SEWER SERVICE IS PROVIDED BY CITY OF RENTON••••••Section III. Bond Worksheet•This section calculates the required Permit Bond for construction permit issuance as well as the required Maintenance Bond for project close‐out submittals to release the permit bond on a project. All unit prices include labor, equipment, materials, overhead and profit. Complete the 'Quantity' columns for each of the appropriate section(s). Include existing Right‐of‐Way (ROW), Future Public Improvements and Private Improvements.The 'Quantity Remaining' column is only to be used when a project is under construction. The City allows one (1) bond reduction during the life of the project with the exception of the maintenance period reduction.Excel will auto‐calculate and auto‐populate the relevant fields and subtotals throughout the document. Only the 'Quantity' columns should need completing.Additional items not included in the lists can be added under the "write‐in" sections. Provide a complete description, cost estimate and unit of measure for each write‐in item. Note: Private improvements, with the exception of stormwater facilities, are not included in the bond amount calculation, but must be entered on the form. Stormwater facilities (public and private) are required to be included in the bond amount.BOND QUANTITY WORKSHEET INSTRUCTIONSThis worksheet is intended to be a "working" copy of the bond quantity worksheet, which will be used throughout all phases of the project, from initial submittal to project close‐out approval. Submit this workbook, in its entirety, as follows:The following forms are to be completed by the engineer/developer/applicant as applicable to the project: The Bond Worksheet form will auto‐calculate and auto‐populate from the information provided in Section I and Section II.This section includes all pertinent information for the projectSection II contains a separate spreadsheet TAB for each of the following specialties: (1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for civil construction permit submittal. Hard copies are to be included as part of the Technical Information Report (TIR).(1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for final close‐out submittal.This section must be completed in its entiretyInformation from this section auto‐populates to all other relevant areas of the workbookPage 1 of 14Ref 8‐H Bond Quantity WorksheetINSTRUCTIONSUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date Prepared: Name:PE Registration No:Firm Name:Firm Address:Phone No.Email Address:Project Name: Project Owner:CED Plan # (LUA):Phone:CED Permit # (U):Address: Site Address:Street Intersection:Addt'l Project Owner:Parcel #(s):Phone:Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NOWater Service Provided by:If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONCITY OF RENTONCITY OF RENTON1 Select the current project status/phase from the following options: For Approval ‐ Preliminary Data Enclosed, pending approval from the City; For Construction ‐ Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout ‐ Final Costs and Quantities Enclosed for Project Close‐out SubmittalEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and GradingUtility ProvidersN/AProject Location and DescriptionProject Owner InformationEnergize EastsideBellevue, WA 98009See attached Parcel ListBradley Strauch, PSELUA‐18‐000055425‐456‐2556 / 425‐214‐625012/30/2020Prepared by:FOR CONSTRUCTIONProject Phase 1ty.johnson@hdrinc.comTy JohnsonPE Registration No. 41381HDR Inc.905 Plum Street, Suite 200, Town Square 3360‐570‐4400N/A ‐ within PSE's easementPO Box 97034, EST‐03WN/AAbbreviated Legal Description:N/A ‐ within PSE's easementPage 2 of 14Ref 8‐H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:UnitReference # Price Unit Quantity CostBackfill & compaction‐embankmentESC‐16.50$ CY Check dams, 4" minus rockESC‐2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC‐335.50$ Each 6213.00Crushed surfacing 1 1/4" minusESC‐4WSDOT 9‐03.9(3)95.00$ CY DitchingESC‐59.00$ CY Excavation‐bulkESC‐62.00$ CY Fence, siltESC‐7SWDM 5.4.3.11.50$ LF Fence, Temporary (NGPE)ESC‐81.50$ LF Geotextile FabricESC‐92.50$ SY Hay Bale Silt TrapESC‐100.50$ Each HydroseedingESC‐11SWDM 5.4.2.40.80$ SY Interceptor Swale / DikeESC‐121.00$ LF Jute MeshESC‐13SWDM 5.4.2.23.50$ SY Level SpreaderESC‐141.75$ LF Mulch, by hand, straw, 3" deepESC‐15SWDM 5.4.2.12.50$ SY Mulch, by machine, straw, 2" deepESC‐16SWDM 5.4.2.12.00$ SY Piping, temporary, CPP, 6"ESC‐1712.00$ LF Piping, temporary, CPP, 8"ESC‐1814.00$ LF Piping, temporary, CPP, 12"ESC‐1918.00$ LF Plastic covering, 6mm thick, sandbaggedESC‐20SWDM 5.4.2.34.00$ SY Rip Rap, machine placed; slopesESC‐21WSDOT 9‐13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC‐22SWDM 5.4.4.11,800.00$ Each Rock Construction Entrance, 100'x15'x1'ESC‐23SWDM 5.4.4.13,200.00$ Each 13,200.00Sediment pond riser assemblyESC‐24SWDM 5.4.5.22,200.00$ Each Sediment trap, 5' high berm ESC‐25SWDM 5.4.5.119.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC‐26SWDM 5.4.5.170.00$ LF Seeding, by handESC‐27SWDM 5.4.2.41.00$ SY 17001,700.00Sodding, 1" deep, level groundESC‐28SWDM 5.4.2.58.00$ SY Sodding, 1" deep, sloped groundESC‐29SWDM 5.4.2.510.00$ SY TESC SupervisorESC‐30110.00$ HR 909,900.00Water truck, dust controlESC‐31SWDM 5.4.7140.00$ HR 243,360.00UnitReference # Price Unit Quantity Cost EROSION/SEDIMENT SUBTOTAL: 18,373.00SALES TAX @ 10% 1,837.30EROSION/SEDIMENT TOTAL: 20,210.30(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)WRITE‐IN‐ITEMS Page 3 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostGENERAL ITEMS Backfill & Compaction‐ embankment GI‐16.00$ CYBackfill & Compaction‐ trench GI‐29.00$ CYClear/Remove Brush, by hand (SY) GI‐31.00$ SYBollards ‐ fixed GI‐4 240.74$ EachBollards ‐ removable GI‐5 452.34$ EachClearing/Grubbing/Tree Removal GI‐6 10,000.00$ AcreExcavation ‐ bulk GI‐72.00$ CYExcavation ‐ Trench GI‐85.00$ CYFencing, cedar, 6' high GI‐9 20.00$ LFFencing, chain link, 4' GI‐10 38.31$ LFFencing, chain link, vinyl coated, 6' high GI‐11 20.00$ LFFencing, chain link, gate, vinyl coated, 20' GI‐12 1,400.00$ EachFill & compact ‐ common barrow GI‐13 25.00$ CYFill & compact ‐ gravel base GI‐14 27.00$ CYFill & compact ‐ screened topsoil GI‐15 39.00$ CYGabion, 12" deep, stone filled mesh GI‐16 65.00$ SYGabion, 18" deep, stone filled mesh GI‐17 90.00$ SYGabion, 36" deep, stone filled mesh GI‐18 150.00$ SYGrading, fine, by hand GI‐19 2.50$ SYGrading, fine, with grader GI‐20 2.00$ SYMonuments, 3' Long GI‐21 250.00$ EachSensitive Areas Sign GI‐22 7.00$ EachSodding, 1" deep, sloped ground GI‐23 8.00$ SYSurveying, line & grade GI‐24 850.00$ DaySurveying, lot location/lines GI‐25 1,800.00$ AcreTopsoil Type A (imported) GI‐26 28.50$ CYTraffic control crew ( 2 flaggers )GI‐27 120.00$ HRTrail, 4" chipped wood GI‐28 8.00$ SYTrail, 4" crushed cinder GI‐29 9.00$ SYTrail, 4" top course GI‐30 12.00$ SYConduit, 2" GI‐31 5.00$ LFWall, retaining, concrete GI‐32 55.00$ SFWall, rockery GI‐33 15.00$ SFSUBTOTAL THIS PAGE:(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)Page 4 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000sy RI‐1 30.00$ SYAC Grinding, 4' wide machine 1000‐2000sy RI‐2 16.00$ SYAC Grinding, 4' wide machine > 2000sy RI‐3 10.00$ SYAC Removal/Disposal RI‐4 35.00$ SYBarricade, Type III ( Permanent )RI‐5 56.00$ LFGuard Rail RI‐6 30.00$ LFCurb & Gutter, rolled RI‐7 17.00$ LFCurb & Gutter, vertical RI‐8 12.50$ LFCurb and Gutter, demolition and disposal RI‐9 18.00$ LFCurb, extruded asphalt RI‐10 5.50$ LFCurb, extruded concrete RI‐11 7.00$ LFSawcut, asphalt, 3" depth RI‐12 1.85$ LFSawcut, concrete, per 1" depth RI‐13 3.00$ LFSealant, asphalt RI‐14 2.00$ LFShoulder, gravel, 4" thick RI‐15 15.00$ SYSidewalk, 4" thick RI‐16 38.00$ SYSidewalk, 4" thick, demolition and disposal RI‐17 32.00$ SYSidewalk, 5" thick RI‐18 41.00$ SYSidewalk, 5" thick, demolition and disposal RI‐19 40.00$ SYSign, Handicap RI‐20 85.00$ EachStriping, per stall RI‐21 7.00$ EachStriping, thermoplastic, ( for crosswalk )RI‐22 3.00$ SFStriping, 4" reflectorized line RI‐23 0.50$ LFAdditional 2.5" Crushed Surfacing RI‐24 3.60$ SYHMA 1/2" Overlay 1.5" RI‐25 14.00$ SYHMA 1/2" Overlay 2" RI‐26 18.00$ SYHMA Road, 2", 4" rock, First 2500 SY RI‐27 28.00$ SYHMA Road, 2", 4" rock, Qty. over 2500SY RI‐28 21.00$ SYHMA Road, 4", 6" rock, First 2500 SY RI‐29 45.00$ SYHMA Road, 4", 6" rock, Qty. over 2500 SY RI‐30 37.00$ SYHMA Road, 4", 4.5" ATB RI‐31 38.00$ SYGravel Road, 4" rock, First 2500 SY RI‐32 15.00$ SYGravel Road, 4" rock, Qty. over 2500 SY RI‐33 10.00$ SYThickened Edge RI‐34 8.60$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 5 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)PARKING LOT SURFACING No.2" AC, 2" top course rock & 4" borrow PL‐1 21.00$ SY2" AC, 1.5" top course & 2.5" base course PL‐2 28.00$ SY4" select borrow PL‐35.00$ SY1.5" top course rock & 2.5" base course PL‐4 14.00$ SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATION No.Street Trees LA‐1Median Landscaping LA‐2Right‐of‐Way Landscaping LA‐3Wetland Landscaping LA‐4SUBTOTAL LANDSCAPING & VEGETATION:(B)(C)(D)(E)TRAFFIC & LIGHTING No.Signs TR‐1Street Light System ( # of Poles) TR‐2Traffic Signal TR‐3Traffic Signal Modification TR‐4SUBTOTAL TRAFFIC & LIGHTING:(B)(C)(D)(E)WRITE‐IN‐ITEMSSUBTOTAL WRITE‐IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:SALES TAX @ 10%STREET AND SITE IMPROVEMENTS TOTAL:(B)(C)(D)(E)Page 6 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D‐1 26.00$ SY* (CBs include frame and lid)Beehive D‐2 90.00$ EachThrough‐curb Inlet Framework D‐3 400.00$ EachCB Type ID‐4 1,500.00$ EachCB Type IL D‐5 1,750.00$ EachCB Type II, 48" diameter D‐6 2,300.00$ Each for additional depth over 4' D‐7 480.00$ FTCB Type II, 54" diameter D‐8 2,500.00$ Each for additional depth over 4' D‐9 495.00$ FTCB Type II, 60" diameter D‐10 2,800.00$ Each for additional depth over 4' D‐11 600.00$ FTCB Type II, 72" diameter D‐12 6,000.00$ Each for additional depth over 4' D‐13 850.00$ FTCB Type II, 96" diameter D‐14 14,000.00$ Each for additional depth over 4' D‐15 925.00$ FTTrash Rack, 12" D‐16 350.00$ EachTrash Rack, 15" D‐17 410.00$ EachTrash Rack, 18" D‐18 480.00$ EachTrash Rack, 21" D‐19 550.00$ EachCleanout, PVC, 4" D‐20 150.00$ EachCleanout, PVC, 6" D‐21 170.00$ EachCleanout, PVC, 8" D‐22 200.00$ EachCulvert, PVC, 4" D‐23 10.00$ LFCulvert, PVC, 6" D‐24 13.00$ LFCulvert, PVC, 8" D‐25 15.00$ LFCulvert, PVC, 12" D‐26 23.00$ LFCulvert, PVC, 15" D‐27 35.00$ LFCulvert, PVC, 18" D‐28 41.00$ LFCulvert, PVC, 24" D‐29 56.00$ LFCulvert, PVC, 30" D‐30 78.00$ LFCulvert, PVC, 36" D‐31 130.00$ LFCulvert, CMP, 8" D‐32 19.00$ LFCulvert, CMP, 12" D‐33 29.00$ LFSUBTOTAL THIS PAGE:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B) (C)Page 7 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B) (C)DRAINAGE (Continued)Culvert, CMP, 15" D‐34 35.00$ LFCulvert, CMP, 18" D‐35 41.00$ LFCulvert, CMP, 24" D‐36 56.00$ LFCulvert, CMP, 30" D‐37 78.00$ LFCulvert, CMP, 36" D‐38 130.00$ LFCulvert, CMP, 48" D‐39 190.00$ LFCulvert, CMP, 60" D‐40 270.00$ LFCulvert, CMP, 72" D‐41 350.00$ LFCulvert, Concrete, 8" D‐42 42.00$ LFCulvert, Concrete, 12" D‐43 48.00$ LFCulvert, Concrete, 15" D‐44 78.00$ LFCulvert, Concrete, 18" D‐45 48.00$ LFCulvert, Concrete, 24" D‐46 78.00$ LFCulvert, Concrete, 30" D‐47 125.00$ LFCulvert, Concrete, 36" D‐48 150.00$ LFCulvert, Concrete, 42" D‐49 175.00$ LFCulvert, Concrete, 48" D‐50 205.00$ LFCulvert, CPE Triple Wall, 6" D‐51 14.00$ LFCulvert, CPE Triple Wall, 8" D‐52 16.00$ LFCulvert, CPE Triple Wall, 12" D‐53 24.00$ LFCulvert, CPE Triple Wall, 15" D‐54 35.00$ LFCulvert, CPE Triple Wall, 18" D‐55 41.00$ LFCulvert, CPE Triple Wall, 24" D‐56 56.00$ LFCulvert, CPE Triple Wall, 30" D‐57 78.00$ LFCulvert, CPE Triple Wall, 36" D‐58 130.00$ LFCulvert, LCPE, 6" D‐59 60.00$ LFCulvert, LCPE, 8" D‐60 72.00$ LFCulvert, LCPE, 12" D‐61 84.00$ LFCulvert, LCPE, 15" D‐62 96.00$ LFCulvert, LCPE, 18" D‐63 108.00$ LFCulvert, LCPE, 24" D‐64 120.00$ LFCulvert, LCPE, 30" D‐65 132.00$ LFCulvert, LCPE, 36" D‐66 144.00$ LFCulvert, LCPE, 48" D‐67 156.00$ LFCulvert, LCPE, 54" D‐68 168.00$ LFSUBTOTAL THIS PAGE:(B) (C) (D) (E)Page 8 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B) (C)DRAINAGE (Continued)Culvert, LCPE, 60" D‐69 180.00$ LFCulvert, LCPE, 72" D‐70 192.00$ LFCulvert, HDPE, 6" D‐71 42.00$ LFCulvert, HDPE, 8" D‐72 42.00$ LFCulvert, HDPE, 12" D‐73 74.00$ LFCulvert, HDPE, 15" D‐74 106.00$ LFCulvert, HDPE, 18" D‐75 138.00$ LFCulvert, HDPE, 24" D‐76 221.00$ LFCulvert, HDPE, 30" D‐77 276.00$ LFCulvert, HDPE, 36" D‐78 331.00$ LFCulvert, HDPE, 48" D‐79 386.00$ LFCulvert, HDPE, 54" D‐80 441.00$ LFCulvert, HDPE, 60" D‐81 496.00$ LFCulvert, HDPE, 72" D‐82 551.00$ LFPipe, Polypropylene, 6" D‐83 84.00$ LFPipe, Polypropylene, 8" D‐84 89.00$ LFPipe, Polypropylene, 12" D‐85 95.00$ LFPipe, Polypropylene, 15" D‐86 100.00$ LFPipe, Polypropylene, 18" D‐87 106.00$ LFPipe, Polypropylene, 24" D‐88 111.00$ LFPipe, Polypropylene, 30" D‐89 119.00$ LFPipe, Polypropylene, 36" D‐90 154.00$ LFPipe, Polypropylene, 48" D‐91 226.00$ LFPipe, Polypropylene, 54" D‐92 332.00$ LFPipe, Polypropylene, 60" D‐93 439.00$ LFPipe, Polypropylene, 72" D‐94 545.00$ LFCulvert, DI, 6" D‐95 61.00$ LFCulvert, DI, 8" D‐96 84.00$ LFCulvert, DI, 12" D‐97 106.00$ LFCulvert, DI, 15" D‐98 129.00$ LFCulvert, DI, 18" D‐99 152.00$ LFCulvert, DI, 24" D‐100 175.00$ LFCulvert, DI, 30" D‐101 198.00$ LFCulvert, DI, 36" D‐102 220.00$ LFCulvert, DI, 48" D‐103 243.00$ LFCulvert, DI, 54" D‐104 266.00$ LFCulvert, DI, 60" D‐105 289.00$ LFCulvert, DI, 72" D‐106 311.00$ LFSUBTOTAL THIS PAGE:(B) (C) (D) (E)Page 9 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B) (C)Specialty Drainage ItemsDitching SD‐19.50$ CYFlow Dispersal Trench (1,436 base+) SD‐3 28.00$ LF French Drain (3' depth) SD‐4 26.00$ LFGeotextile, laid in trench, polypropylene SD‐53.00$ SYMid‐tank Access Riser, 48" dia, 6' deep SD‐6 2,000.00$ EachPond Overflow Spillway SD‐7 16.00$ SYRestrictor/Oil Separator, 12" SD‐8 1,150.00$ EachRestrictor/Oil Separator, 15" SD‐9 1,350.00$ EachRestrictor/Oil Separator, 18" SD‐10 1,700.00$ EachRiprap, placed SD‐11 42.00$ CYTank End Reducer (36" diameter) SD‐12 1,200.00$ EachInfiltration pond testing SD‐13 125.00$ HRPermeable Pavement SD‐14Permeable Concrete Sidewalk SD‐15Culvert, Box __ ft x __ ft SD‐16SUBTOTAL SPECIALTY DRAINAGE ITEMS:(B) (C) (D) (E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention Pond SF‐1Each Detention Tank SF‐2Each Detention Vault SF‐3Each Infiltration Pond SF‐4Each Infiltration Tank SF‐5Each Infiltration Vault SF‐6Each Infiltration Trenches SF‐7Each Basic Biofiltration Swale SF‐8Each Wet Biofiltration Swale SF‐9Each Wetpond SF‐10 Each Wetvault SF‐11 Each Sand Filter SF‐12 Each Sand Filter Vault SF‐13 Each Linear Sand Filter SF‐14 Each Proprietary Facility SF‐15 Each Bioretention Facility SF‐16 Each SUBTOTAL STORMWATER FACILITIES:(B) (C) (D) (E)Page 10 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESQuantity Remaining (Bond Reduction) (B) (C)WRITE‐IN‐ITEMS (INCLUDE ON‐SITE BMPs)WI‐1WI‐2WI‐3WI‐4WI‐5WI‐6WI‐7WI‐8WI‐9WI‐10WI‐11WI‐12WI‐13WI‐14WI‐15SUBTOTAL WRITE‐IN ITEMS:DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:SALES TAX @ 10%DRAINAGE AND STORMWATER FACILITIES TOTAL:(B) (C) (D) (E)Page 11 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostConnection to Existing Watermain W‐1 2,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch Diameter W‐2 50.00$ LFDuctile Iron Watermain, CL 52, 6 Inch Diameter W‐3 56.00$ LFDuctile Iron Watermain, CL 52, 8 Inch Diameter W‐4 60.00$ LFDuctile Iron Watermain, CL 52, 10 Inch Diameter W‐5 70.00$ LFDuctile Iron Watermain, CL 52, 12 Inch Diameter W‐6 80.00$ LFGate Valve, 4 inch Diameter W‐7 500.00$ EachGate Valve, 6 inch Diameter W‐8 700.00$ EachGate Valve, 8 Inch Diameter W‐9 800.00$ EachGate Valve, 10 Inch Diameter W‐10 1,000.00$ EachGate Valve, 12 Inch Diameter W‐11 1,200.00$ EachFire Hydrant Assembly W‐12 4,000.00$ EachPermanent Blow‐Off Assembly W‐13 1,800.00$ EachAir‐Vac Assembly, 2‐Inch Diameter W‐14 2,000.00$ EachAir‐Vac Assembly, 1‐Inch Diameter W‐15 1,500.00$ EachCompound Meter Assembly 3‐inch Diameter W‐16 8,000.00$ EachCompound Meter Assembly 4‐inch Diameter W‐17 9,000.00$ EachCompound Meter Assembly 6‐inch Diameter W‐18 10,000.00$ EachPressure Reducing Valve Station 8‐inch to 10‐inch W‐19 20,000.00$ EachWATER SUBTOTAL:SALES TAX @ 10%WATER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B) (C)Page 12 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 CED Permit #:Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D) (E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostClean Outs SS‐1 1,000.00$ EachGrease Interceptor, 500 gallon SS‐2 8,000.00$ EachGrease Interceptor, 1000 gallon SS‐3 10,000.00$ EachGrease Interceptor, 1500 gallon SS‐4 15,000.00$ EachSide Sewer Pipe, PVC. 4 Inch Diameter SS‐5 80.00$ LFSide Sewer Pipe, PVC. 6 Inch Diameter SS‐6 95.00$ LFSewer Pipe, PVC, 8 inch Diameter SS‐7 105.00$ LFSewer Pipe, PVC, 12 Inch Diameter SS‐8 120.00$ LFSewer Pipe, DI, 8 inch Diameter SS‐9 115.00$ LFSewer Pipe, DI, 12 Inch Diameter SS‐10 130.00$ LFManhole, 48 Inch Diameter SS‐11 6,000.00$ EachManhole, 54 Inch Diameter SS‐13 6,500.00$ EachManhole, 60 Inch Diameter SS‐15 7,500.00$ EachManhole, 72 Inch Diameter SS‐17 8,500.00$ EachManhole, 96 Inch Diameter SS‐19 14,000.00$ EachPipe, C‐900, 12 Inch Diameter SS‐21 180.00$ LFOutside Drop SS‐24 1,500.00$ LSInside Drop SS‐25 1,000.00$ LSSewer Pipe, PVC, ____ Inch Diameter SS‐26Lift Station (Entire System) SS‐27 LSSANITARY SEWER SUBTOTAL:SALES TAX @ 10%SANITARY SEWER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B) (C)Page 13 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a)Existing Right‐of‐Way Improvements Subtotal (b) (b)‐$ Future Public Improvements Subtotal(c)‐$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d) (d)‐$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond‐$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only ‐ May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. 360‐570‐4400ty.johnson@hdrinc.comEnergize EastsideLUA‐18‐000055N/A ‐ within PSE's easementSee attached Parcel ListFOR CONSTRUCTION 905 Plum Street, Suite 200, Town Square 320,210.30$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS12/30/2020Ty JohnsonPE Registration No. 41381HDR Inc.R((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right‐of‐Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R ‐ S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)EST1((b) + (c) + (d)) x 20%‐$ MAINTENANCE BOND */**(after final acceptance of construction)20,210.30$ ‐$ ‐$ 20,210.30$ ‐$ ‐$ ‐$ Page 14 of 14Ref 8‐H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 12/30/2020 Technical Information Report PSE Energize Eastside – Renton Segment December 29, 2020 | Appendix E – Declaration of Covenant Page 1 of 3 Return Address: City Clerk’s Office City of Renton 1055 S Grady Way Renton, WA 98057 DECLARATION OF COVENANT AND EASEMENT FOR INSPECTION AND MAINTENANCE OF DRAINAGE FACILITIES AND ON-SITE BMPS Grantor: Grantee: City of Renton Legal Description: Assessor's Tax Parcel ID#: IN CONSIDERATION of the approved City of Renton (check one of the following) residential building permit, commercial building permit, clearing and grading permit, subdivision permit, or short subdivision permit for application file No. LUA/SWP_______________________ relating to the real property ("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants(covenant) with the City of Renton, a political subdivision of the state of Washington, that he/she(they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 9 below with regard to the Property, and hereby grants(grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby grants(grant), covenants(covenant), and agrees(agree) as follows: 1. The Grantor(s) or his/her(their) successors in interest and assigns ("Owners ") shall at their own cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed as required in the approved construction plans and specifications __________ on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) _____________________________. The property's drainage facilities are shown and/or listed on Exhibit A. The property’s drainage facilities shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B. Drainage facilities include pipes, channels, flow control facilities, water quality facilities, on-site best management practices (BMPs) and other engineered structures designed to manage and/or treat stormwater on the Property. On-site BMPs include dispersion and infiltration devices, bioretention, permeable pavements, rainwater harvesting systems, tree retention credit, reduced impervious surface footprint, vegetated roofs and other measures designed to mimic pre-developed hydrology and minimize stormwater runoff on the Property. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with the Renton Municipal Code. City of Renton shall provide at least 30 days written notice to the Owners that entry on the Property is Page 2 of 3 planned for the inspection of drainage facilities. After the 30 days, the Owners shall allow the City of Renton to enter for the sole purpose of inspecting drainage facilities. In lieu of inspection by the City, the Owners may elect to engage a licensed civil engineer registered in the state of Washington who has expertise in drainage to inspect the drainage facilities and provide a written report describing their condition. If the engineer option is chosen, the Owners shall provide written notice to the City of Renton within fifteen days of receiving the City’s notice of inspection. Within 30 days of giving this notice, the Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to the City of Renton. If the report is not provided in a timely manner as specified above, the City of Renton may inspect the drainage facilities without further notice. 3. If City of Renton determines from its inspection, or from an engineer’s report provided in accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is required to be done to any of the drainage facilities, City of Renton shall notify the Owners of the specific maintenance, repair, restoration, and/or mitigation work (Work) required pursuant to the Renton Municipal Code. The City shall also set a reasonable deadline for the Owners to complete the Work, or to provide an engineer’s report that verifies completion of the Work. After the deadline has passed, the Owners shall allow the City access to re-inspect the drainage facilities unless an engineer’s report has been provided verifying completion of the Work. If the Work is not completed within the time frame set by the City, the City may initiate an enforcement action and/or perform the required maintenance, repair, restoration, and/or mitigation work and hereby is given access to the Property for such purposes. Written notice will be sent to the Owners stating the City’s intention to perform such work. This work will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the City, there exists an imminent or present danger, the seven (7) day notice period will be waived and maintenance and/or repair work will begin immediately. 4. The Owners shall assume all responsibility for the cost of any maintenance, repair work, or any measures taken by the City to address conditions as described in Paragraph 3. Such responsibility shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such work performed. Overdue payments will require payment of interest at the maximum legal rate allowed by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to enforce this agreement, the prevailing party in such action is entitled to recover reasonable litigation costs and attorney’s fees. 5. The Owners are required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or modifications to the drainage facilities referenced in this Declaration of Covenant. 6. Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail, return receipt requested. 7. With regard to the matters addressed herein, this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever whether oral or written. 8. This Declaration of Covenant is intended to protect the value and desirability and promote efficient and effective management of surface water drainage of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This