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Technical Information Report Talbot Substation Storrnwater Support Puget Sound Energy Renton, Washington November 16, 2016 ,(' 1-)~ DEC O 6 2016 This page intentionally left blank. Certificate of Engineer The technical material and data contained in this report for the Puget Sound Energy Talbot Substation Stormwater Support Project were prepared under the supervision and direction of the undersigned, whose seal, as a professional engineer licensed to practice as such, is affixed below. Beth Peterson, P.E. Project Manager HDR Engineering, Inc. / This page intentionally left blank. Technical Information Report 1-)"' Talbot Substation Stormwater Support ~ Contents Project Overview ............................................................................................................................... . 1.1 Existing Conditions ................. 1 1.2 Proposed Conditions ................... . .............. 2 2 Conditions and Requirements Summary ............................................................................................ 2 3 Off site Analysis .................................................................................................................................... 4 4 Flow Control and Water Quality Facility Analysis and Design ............................................................ 8 5 Conveyance System Analysis and Design ........................................................................................ 13 6 Special Reports and Studies ........................................................................................................ 13 7 Other Permits .................................................................................................................................... 13 8 CSWPPP Analysis and Design ......................................................................................................... 14 9 Bond Quantities, Facility Summaries, and Declaration of Covenant ................................................ 17 10 Operations and Maintenance Manual ..................................... . ... 17 11 References ......................................................................... . . ......... 17 Tables Table 1: Existing Condition Acreage and Peak Flow Values ........................................................................ 8 Table 2: Proposed Condition Acreage and Peak Flow Values ..................................................................... 9 Table 3: Existing and Proposed Land Use Summary ................................................................................. 10 Table 4: Pre-developed and Proposed Controlled Flow Comparison... . ............................... 12 Table 5: Additional Project Permit Requirements ....................................................................................... 14 Figures Figure 1: TIR Worksheet Figure 2: Site Location Figure 3: Drainage Basins, Subbasins, and Site Characteristics Figure 4: Soils Figure 5: Flow Chart for Determining Type of Drainage Review Required Figure 6: Offsite Analysis Figure 7: Existing Hydrology Figure 8: Proposed Hydrology Figure 9: Flow Chart for Determining Individual Lot BMP Requirements of the SWDM Figure 10: Pond Sketch November 16, 2016 I i Technical lnforrnation Report Talbot Substation Stormwater Support Appendix A: Firmette Appendix B: Drainage System Table Appendix C: Site Photos Appendices Appendix D: Reference 11-A Flow Control Areas Appendix E: Stormwater Model Output Appendix F: Construction Stormwater Pollution Prevention Plan Appendix G: Facility Summaries and Declaration of Covenant Appendix H: Operations and Maintenance Manual ii I November 16, 2016 Technical Information Report L 1 )"'\ Talbot Substation Stormwater Support r-; ~ 1 Project Overview 1 .1 1.1.1 1.1.2 Puget Sound Energy (PSE) is proposing a series of improvements at their Talbot Substation located in Renton, Washington. A copy of the TIR Worksheet (Figure 1) is located below. Figure 2 below shows the site location and adjacent critical areas. Proposed improvements will occur on the eastern side of the substation (referred to as the project area), and will include the installation of foundations, security perimeter fence, landscape screening, paving of a small portion of the access road, installation of a new stormwater drainage and flow control system, road maintenance, and on-site oil spill control best management practices (BMPs). The extent of disturbance will be approximately 5.89 acres. Approximately 4.17 acres will consist of gravel road and surface improvements. Another 1.22 acres will be for the installation of new foundations and Spill Prevention, Control, and Countermeasures (SPCC) structures. The remaining 0.5 acres will be for installation of a stormwater detention pond. The existing site contains electrical structures, and yard rock covers the ground surface. The existing and proposed conditions as well as the site constraints are described below. Existing Conditions Topography The Talbot substation covers approximately 7.75 acres between Beacon Way South, South Puget Drive, and Grant Ave South in Renton, Washington, as shown in Figure 2. The site is located near the top of a ridge and is primarily accessed from South Puget Drive, which ties into a gravel driveway leading to the site. The topography inside the substation slopes slightly away from the center to promote drainage away from electrical equipment. The existing grade outside the substation fence generally slopes away from the substation except on the eastern and northwestern sides where there is elevated terrain. Drainage In general stormwater runoff flows outwards from the middle of the substation. Existing drainage pipes on the northeast and southeast sides of the substation are tied to catch basins within the fence line whose rims are slightly raised above the yard rock, preventing them from capturing flow. The perimeter path on the northeastern side of the substation is higher than the existing grade within the fence line, preventing flow from draining off the site along this edge. An elevated field along the eastern edge of the site prevents drainage away from the substation on this side. Runoff along the northeastern, eastern, and southeastern sides of the substation therefore tends to pond within the substation and infiltrate. Along the southern edge of the substation, runoff is able to flow south across the southern perimeter path and into a depression located between the substation and access road. This route presents the path of least resistance for stormwater. The depression is drained by a culvert beneath the access road to a second depression which drains eastwards, towards Grant Avenue South. Existing drainage patterns are shown in Figure 3. Existing soil types can be found on Figure 4. November 16, 2016 I 1 2009 Surface Water Design Manual KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 119/2009 KING COUNTY, WAS!IINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Project Owner Puget Sound Energy Phone 425-456-2127 Address _.,,3"'-5"'-5----'1---'-1-"'0t"-h'---'A---'-v'--'e"---'---'N--=E"---- Bellevue, WA 98004 Project Engineer Chris Russell Company Puget Sound Energy Phone Puget Sound Energy Part 3 TYPE OF PERMIT APPLICATION D Landuse Services Subdivison / Short Subd. / UPD D Building Services M/F / Commerical / SFR D Clearing and Grading D Right-of-Way Use D Other Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review @Di Targeted (circle) Large Site Date (include revision dates): Date of Final: Part 6 ADJUSTMENT APPROVALS I Part 2 PROJECT LOCATION AND DESCRIPTION Project Name Talbot Stormwater Support DDES Permit# ---------- Location Township 23 N Range 5 E Section --"'20=------ Site Address 1601 Seagull Drive, Renton, WA 98055 Part 4 OTHER REVIEWS AND PERMITS D DFWHPA 0 COE404 D DOE Dam Safety D FEMA Floodplain D COE Wetlands D Other __ _ D Shoreline Management D Structural RockeryNaultl __ D ESA Section 7 Site Improvement Plan (Engr. Plans) Type (circle one): <@))1 Modified I Small Site Date (include revision dates): Date of Final: Type (circle one): Standard I Complex I Preapplication I Experimental/ Blanket Description: (include conditions in TIR Section 2) Date of Annroval: 2009 Surface Water Design Manual 1/912009 1 KING COUNTY, WASHINGTON, SLRl'ACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan:~------------- Special District Overlays:-------------------------- Drainage Basin: _D_uw_a_m_is_h_R_iv_er __________ _ Stormwater Requirements: Core Requirements# 1 through #8 of the City of Renton Amendment to the 2009 King County Surface Water Desi n Manual Part 9 ONSITE AND ADJACENT SENSITIVE AREAS D River/Stream _________ _ D Lake D Wetlands __________ _ D Closed Depression -------- D Floodplain----------- D Other ___________ _ Part 10 SOILS Soil Type Slopes AmC -Arents, Alderwood material 6 to 15% AgC -Alderwood gravelly sandy loam 8 to 15% AgD -Alderwood gravelly sandy loam 15to30% D High Groundwater Table (within 5 feet) D Other D Additional Sheets Attached 2009 Surface Water Design Manual 2 lif Steep Slope ________ _ !if Erosion Hazard _______ _ Gl Landslide Hazard _______ _ ~ Coal Mine Hazard _______ _ Gr Seismic Hazard -------- D Habitat Protection-------- D --------------- Erosion Potential Low (Kfactorof0.10} Low (K factor of 0.10) Low {K factor of 0.10) D Sole Source Aquifer D Seeps/Springs 1/9/2009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION/ SITE CONSTRAINT D Core 2 -Olfsite Analysis D Sensitive/Critical Areas D SEPA D Other D D Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summarv Sheet oar Threshold Discharae Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply) Dischar;ie at Natural Location Number of Natural Discharae Locations: 1 Olfsite Analysis Level: (.j_) 2 I 3 dated: Janua!:J:: 18th 1 2016 Flow Control Level: (.j_J 2 / 3 or Exemption Number (incl. facilitv summarv sheet) Small Site BMPs Conveyance System Spill containment located at: Around transformers on site Erosion and Sediment Control ESC Site Supervisor: Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: V-'rivato'> / Public If Private, Maintenance Loa Reauired: Yes / No Financial Guarantees and Provided: Yes / No Liabilitv Water Quality Type: Basic / Sens. Lake / Enhanced Basicm / Bog (include facility summary sheet) or Exemption No. Surface area exemption number 1. Landscape Manaaement Plan: Yes / No Special Reciuirements (as annlicablel Area Specific Drainage Type: CDA / SDO I MOP/ BP/ LMP / Shared Fae.• None '> Requirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption /~ 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: None present Source Control Describe landuse: NIA (comm./industrial landuse) Describe any structural controls: NIA 2009 Surface Water Design Manual 1/9/2009 3 KING COUNTY, W ASIIINGTON, SURFACE WAT LR DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Oil Control High-use Site: Yes" No ) Treatment BMP: Maintenance Agreement: Yes~ with whom? Other Drainaae Structures Describe: Oil spill prevention, containment, and control structures will be placed around electrical facilities which employ oil. Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ri:f Clearing Limits 0 Stabilize Exposed Surfaces [if" Cover Measures 0 Remove and Restore Temporary ESC Facilities ri:f Perimeter Protection [if" Clean and Remove All Silt and Debris, Ensure [if" Traffic Area Stabilization Operation of Permanent Facilities ri:f Sediment Retention 0 Flag Limits of SAO and open space ri:f Surface Water Collection preservation areas 0 Other 0 Dewatering Control 0 Dust Control [if" Flow Control Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summarv and Sketch) Flow Control Tyoe/Descriotion Water Quality Tvne/Descriotion ~ Detention Detention pond 0 Biofiltration 0 Infiltration 0 Wetpool 0 Regional Facility 0 Media Filtration 0 Shared Facility 0 Oil Control 0 Flow Control 0 Spill Control BMPs 0 Flow Control BMPs 0 Other 0 Other 2009 Surface Water Design Manual 4 1/9/2009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS D Drainage Easement 0 Cast in Place Vault D Covenant D Retaining Wall D Native Growth Protection Covenant D Rockery> 4' High D Tract D Structural on Steep Slope D other D Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Sinned/Date 2009 Surface Water Design Manual 1/9/2009 5 This page intentionally left blank. 1 LEGEND r·--· • 1 1 Project A re a ..... Roads ,.;'\,--Stre ams [ZJ Coalmine Hazard Area Wetlands Landslide Haza rd Steep Slo pes DATA SOURCE: City of Renlon. King Courty (2016) Feet 500 ~ )~ SITE LOCATION FIGURE 2 PA™ O:'lf'JtOJECT1\WASHINOTONIP'VOn_ SOUNO_EMEROY _0070121TA.L &OT_STORMWATE"-SUf'PORT_2CttHU,!AP _OOCS'OftAFnTIR F IOUFID'#IOUl':li_2 _S1TI_I..OCATION.MXO -USIEft: T.IHOl"l"M.1 · DATE 11M"2011 STORMWATER TIR I L:] P roje ct A rea Contours - I 10ft l nterva l E xis tin g ~ -Flow Path I~ ~ri~0 ::~ Exi st ing =-=> Drainage Inf ras tructu re Pro p osed ---Dra ina ge Infrastruc ture c'--. Proposed I (__./ Detenti on Po nd ~ Pon ded Wat er I • Observ e d During I Fie ld V is it DATA SOUR C E: C ity cJ Renton, I King County (2016) ,~ l~ 'i 0 Feet 250 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS FIGURE 3 PATH; 0 I.PAOJEC TI\WASHIHOTON\f"OOfl_SOUNO_ENEROY_0070lllTALIOT_STORMWATER_SUPPORT_M ttM\MA P _OOCIIDRA,CTIT IR ,:IQUR&iS\HQU~_3_0 RAlNAQli MXO UH:A. TAHOF'FMA • OATli 11 /lt/2011 STORMWATE R TIR LEGEND 1--.. '---' Proj ect Area C] Soil Group Roads D ATA SOURCE : USDA web So<! Survey, King County & 0 Feet 190 1-)~ Pit. nt: C:IPROJECTS \WASHING TONIPVG!T _SOUNC_ENERGY _c.o1on,TALBOT_STOftMWA T'ER_SUPPORT_2HHS\MA.P _OOCS'ORAl'nffl ,iou lU!SV'IGUftl!:_ ._SOrt.S.MJlO . US!!\ TA.HO,,M.A .. DA.TE: t1/1 l f2()1C SOILS FIGUR E 4 STORMWATER TIR Technical Information Report Talbot Substation Stormwater Support 1.2 Proposed Conditions Proposed conditions will include a re-graded gravel surface within the substation (approximately 3.43 acres), additional SPCC structures and equipment foundations (approximately 1.22 acres), re-grading of gravel and asphalt roads (approximately 0.74 acres), and the addition of a pond for flow control (approximately 0.5 acres). The proposed conditions will increase impervious area at the site by approximately 15%. This percentage is primarily due to the addition of the SPCC structures and equipment foundations, as well as asphalt entries to the gravel access driveways. Yard rock surfaces will only be replaced or re-graded, they will not be added. The gravel surface inside the fence line of the substation will be re-graded to smooth any slight depressions in the gravel, promote flow to catch basins, and subsequently limit ponding around electrical equipment and structures. The proposed improvements will not significantly modify the grade of the existing substation or access roads. The impervious SPCC structures and equipment foundations will be added within the substation fence. The asphalt surface will be added at the intersection of the gravel access way and South Puget Drive. Drainage improvements include a new stormwater conveyance network inside the substation which will route flows to a 75,000 cubic foot stormwater detention pond located along the southeastern edge of the substation. This pond will discharge to a depression on the southern side of the existing access road, where flow will resume the existing drainage path towards Grant Avenue South. Proposed drainage facilities can be found on Figure 3. Landscape screening will be installed along the southwest side of the substation property border and the perimeter of the pond. Landscaping will replace non-native plant cover such as blackberry shrubs and non-native grasses. 2 Conditions and Requirements Summary The project is subject to the City of Renton Amendments to the 2009 King County Surface Water Design Manual (KCSWDM), as well as the City of Renton Municipal Code. According to Section 1.1.1 of the City of Renton Amendments to the KCSWDM (COR SWDM), projects resulting in 2,000 square feet or more of new impervious surface, replaced impervious surface, or new plus impervious surface, or 7,000 square feet or more of land disturbing activity require a Drainage Review. Additionally, per Section 1. 1.2 of the COR SWDM projects which result in greater than 2,000 square feet of new impervious surface and greater than 35,000 square feet of pervious surface are required to perform a Full Drainage Review. Figure 5 contains the Flow Chart for Determining Type of Drainage Review Required and shows that the project requires a Full Drainage Review. Projects undergoing a Full Drainage Review must meet the Core Requirements and Special Requirements contained in the COR SWDM. These requirements are broken down and discussed in greater detail below. 2 I November 16, 2016 Technical Information Report L "\~ Talbot Substation Stormwater Support r J'~ 2.1 Core Requirement #1 : Discharge at the Natural Location Proposed projects must discharge runoff at the natural location and comply with the discharge requirements of Core Requirement #1. The proposed stormwater detention pond which collects runoff from the conveyance system within the substation discharges to the natural discharge location, as shown on Figure 3. Per the discharge requirements of Core Requirement# 1, if the proposed 100-year flow event peak discharge is greater than 0.5 CFS a conveyance system must be provided to convey concentrated runoff to an acceptable discharge point (COR SWDM, 2009). The 100-year peak flow event for the proposed project is larger than 0.5 CFS, and will be routed through the proposed conveyance system and stormwater detention pond to the natural discharge location. The proposed stormwater detention pond will control stormwater flows generated by the substation and discharge at a rate that meets the flow control regulatory requirements. 2.2 Core Requirement #2: Offsite Analysis Core Requirement #2 is discussed in detail in Section 3 of this report. 2.3 Core Requirement #3: Flow Control Core Requirement #3 is discussed in detail in Section 4 of this report. 2.4 Core Requirement #4: Conveyance System Core Requirement #4 is discussed in detail in Section 5 of this report. 2.5 Core Requirement #5: Erosion and Sediment Control Core Requirement #5 is discussed in detail in Section 8 of this report. 2.6 Core Requirement #6: Maintenance and Operations Core Requirement #6 is discussed in detail in Section 1 O of this report. 2.7 Core Requirement #7: Financial Guarantees and Liability Core Requirement# 7 is discussed in detail in Section 9 of this report. 2.8 Core Requirement #8: Water Quality The project site qualifies for the Surface Area Exemption detailed in Section 1.2.8 of the COR SWDM (City of Renton, 2009). • Less than 5,000 square feet of new PGIS that is not fully dispersed will be added and November 16, 2016 I 3 Technical Information Report Talbot Substation Stormwater Support • less than 5,000 square feet of new plus replaced PGIS that is not fully dispersed will be created as part of a redevelopment project and • less than 35,000 square feet of new PGPS that is not fully dispersed will be added. Because this project adds less than 5,000 square feet of PGIS and less than 35,000 square feet of new PGPS, water quality facilities are not required at the project site. 2.9 Special Requirement #1 : Adopted Area Specific Regulations 2.10 2.11 2.12 2.13 This requirement is not applicable as there are no adopted area specific regulations within the project area. Special Requirement #2: Flood Hazard Area Delineation This requirement is not applicable as the project area is not within or adjacent to a mapped FEMA flood hazard area. The FIRMETIE (a web-based software program designed to display mapped FEMA floodplains) for the project area can be found in Appendix A. Special Requirement #3: Flood Protection Facilities This requirement is not applicable as the proposed project does not rely on an existing flood protection facility or plan to modify or construct a new flood protection facility. Special Requirement #4: Source Controls This requirement is not applicable as the proposed project does not require a commercial building or commercial site development permit. Special Requirement #5: Oil Control This requirement is not applicable as the proposed project does not have high use characteristics. It should be noted that Spill Prevention, Containment, and Control (SPCC) facilities will be installed around some electrical components which employ oil. · 3 Offsite Analysis A Level 1 Analysis was performed to identify any potential drainage, conveyance, or environmental issues downstream of the site that could be affected by the project and require an additional level of analysis. The Level 1 Analysis consists of a resource review and a field inspection where offsite issues are identified. The resource review provides information regarding large-scale existing issues in the project area prior to a site visit. During the field inspection, evidence of on-site and off-site drainage issues or other 4 ] November 16, 2016 Technical Information Report 1-)"' Talbot Substation Stormwater Support ~ environmental problems are investigated and reported. The scale of the resource review and the field inspection are defined by the downstream study area. 3.1 Task 1: Study Area The study area and extent of the downstream analysis can be found on Figure 6. The USGS StreamStats application in tandem with existing topographic and stormwater conveyance data were used to define the downstream drainage path leaving the project site. As mentioned in Section 1.1.2 above, stormwater runoff exits the project site via the southern side of the substation, passing beneath the access road and eventually flowing west towards Grant Avenue South. The study area for Task 2 is required to ex1end 1 mile downstream of the project discharge location per Section 1.2.2.1 of the COR SWDM. The study area is required to extend upstream if backwater or upstream effects are anticipated, however the substations location near the top of a ridge precludes any of these effects. The study area for Tasks 3 through 5 must extend to a point where the proposed project area extends less than 15% of the total tributary drainage area, but not less than one-quarter mile downstream of the project area. StreamStats was used to delineate and calculate the area of the watershed, and then determine at what distance the project area composed less than 15% of the tributary drainage area. This distance was less than the minimum distance, one quarter mile and therefore one quarter mile was used for the extent the study area used in Tasks 3 through 5. 3.2 Task 2: Resource Review The resource review was conducted according to Section 2.3.1.1 of the COR SWDM. Information required to be reviewed includes FEMA Maps, presence of sensitive areas, presence of wetlands, presence of nearby 303d listed waters, soil survey information, adopted basin plans, and offsite analysis reports for other projects. The information obtained during the review is detailed below. Adopted basin plans were not available for the project area as of September 2016. FEMA floodplain information was referenced from the online FEMA Flood Map Service Center. The project site is not located within a flood hazard area. The FIRMETTE which includes the project area is located in Appendix A. King County iMap data indicates that the project area is located inside a Coal Mine Hazard Area and adjacent to an Erosion Hazard Area. City of Renton GIS data was also analyzed, and shows that environmentally sensitive or critical areas located near the project area include erosion hazard areas and landslide areas (Figure 2). The closest high-risk erosion hazard area is approximately 1,400 ft west/southwest of the site. Moderate hazard landslide areas are present on the south, southwest, and west sides of the project site. The closest high hazard landslide area is approximately 2,000 feet west of the site. The project area will not discharge directly to any erosion or landslide hazard areas. King County iMap data indicates drainage complaints approximately three quarters of a mile west of the project area, adjacent to 1-405. The registered complaints were for November 16, 2016 I 5 Technical Information Report Talbot Substation Stormwater Support garbage dumping. The stormwater discharge from the proposed project area should not have an effect. Sensitive surface waters reviewed included wetlands and impaired waters. City of Renton Wetland Inventory maps for the area do not show wetlands within one mile downstream of the site. Additionally, following a review of the Department of Ecology's 303d list of impaired waters, no impaired waters were found within one mile downstream of the site. Seven borings were performed as part of a geotechnical study at the project area. Five of the borings were performed inside of the substation, and these discovered several feet of fill soils overlaying seven to twenty-three feet of glacial till. In the area of the proposed stormwater detention pond, two borings were performed which discovered several feet of loose sand and organic topsoil overlaying glacial till. Advance outwash deposits were found below the till soils in all boring samples. No groundwater was encountered at the project site (GeoEngineers, 2016). King County iMap does not identify any stormwater quality problems within the study area. No Basin Plans or Basin Reconnaissance Summary Reports were found for surface waters downstream of the project site, and no nearby offsite analysis reports were obtained as of September 2016 from the City of Renton Development Services Division. Existing and potential problems identified above have been tabulated in the Drainage System Table, located in Appendix B. 3.3 Task 3 through 5: Field Inspection & Results The field inspection was conducted on January 18th, 2016 at the project area and the study area within V. mile downstream of the site. The inspection focused on areas identified in the resource review and in previous site visits, such as steep slopes and erosion hazard areas. The purpose of the inspection was to note any erosion or sedimentation, evidence of recurrent flooding, conveyance system issues, or other drainage issues present, as well as observe existing site conditions and verify the tributary drainage basin of the project site. Site photos taken during the visit are found in Appendix C. It is important to note that the field inspection took place following 0.92 inches of rainfall in the two days prior to the visit, so wet weather conditions were observed. Land use immediately adjacent to the site is primarily undeveloped. Areas to the east and west of the substation consist of tall grasses with interspersed shrubs, and the area south of the site consists of moderate to dense trees and shrubs. Grasses surround the north side of the site, with moderate to dense tree and shrub cover north of the grassy areas. The closest developed area downstream of the site is a residential development approximately 400 feet south of the site. A park lies between the residential development and the substation, and consists of lawn grass and some taller grasses around the border. South of the park is more undeveloped grassy and forested area, with a maintained mountain bike trail in the forested area. A small stream or channel was observed crossing the trail via a culvert. The stream appeared to end in the grass area to 6 I November 16, 2016 Technical Information Report L 1111\9\ Talbot Substation Stormwater Support r J'~ the southwest where it converted to overland flow or infiltrated. No erosion or scour problems were identified in this area. To the east of the project area, the grade gradually slopes upward towards a ridge between the substation and Beacon Way South (gravel road). South of the project area and to the west of the gravel access road the topography is relatively flat. A slight depression is present east of the access road which extends beyond the SE corner of the substation. The west side of the substation is bounded by an approximately 10-ft wide flat area and small ridge. West of the ridge, the grade becomes much steeper. Runoff from the substation is constrained from reaching the steep slope by the ridge feature. The ridge ends just before the southwest corner of the site, where a steep access path leads southwest towards a transmission line tower. To the north of the substation is relatively flat ground with areas of ponding. One depression is present near the NE corner of the site. Two small ponded areas are present along the north edge of the site. No outlets were observed from the ponded areas. Topography downstream of the site consists of gradual slopes across a park and moderate slopes to the west and southwest through forested and grassy areas. A gravel access road intersects an undeveloped area between the park and the substation and leads to a low area south of the road near the tower at the southwest corner of the substation. The low area was identified as an additional area that would likely capture runoff from the substation. The access road continues over a small ridge. Runoff that escaped the low area would enter a forested section crisscrossed with mountain bike paths. Many small depressions were observed along the mountain bike paths. Further downstream is a grassy area west of the park. Moderate slopes continue across the grassy area to Grant Avenue South, approximately V. mile downstream of the site. Despite the steep slopes and paths on the west and south sides of the site, no rills or signs of erosion or sedimentation were present during the field inspection of on-site and off-site areas. Additionally, no evidence of recurrent flooding was present in the area. Ponded areas were small, no overtopping of those areas was apparent, and water levels were fairly low within the depressions despite the recent precipitation. These observations suggest that the on-site and off-site areas do not suffer from erosion or flooding drainage problems which could warrant additional flow control for the project. Conveyance observed off-site in the downstream drainage path during the inspection included two culverts. The outlet of a 4" PVC culvert was observed in a depression on the south side of the site between the access road and substation. No water was flowing in the culvert during the time of the inspection. The second culvert (4" PVC) was observed with flow present underneath a section of the mountain bike trail southwest of the site (Figure 6). About 200 feet downstream of the culvert, the flow converted into overland flow through a grassy area. No flooding or erosion issues were observed around the culvert. Based on the observations made during the field inspection, no downstream drainage problems -such as conveyance, flooding, or erosion issues -could be identified for the project area or downstream drainage path within V. mile of the project area. Field observations also verified the drainage basin delineation discussed in Section 1. The lack of downstream drainage problems confirms that a Level 1 Analysis is sufficient for the study area. November 16, 2016 I 7 SECTION I. I DRAINAGE REVIEW FIGURE 1.1.2.A FLOW CHART FOR DETERMINING TYPE OF DRAINAGE REVIEW REQUIRED Is the project a single family residential project that results in :2:2,000 sf of SMALL PROJECT DRAINAGE new and/or replaced impervious surface or ;;,,-7,000 sf of land disturbing REVIEW activity, AND meets the following criteria? Sec;lion 1.1.2.1 • The project results in :-;;S,000 sf of new impervious surface, and .,;35,000 Nollo: The pro/eCt may also be sf of new pervious surface sul)Jact to Targeted Drainage RevitlW 8$ /1et&nrlined below. Yes Nol l Does the new or redevelopment Does the project have the characteristics of one or more of the following project result in ~2.000 sf of new categories of projects (see more detailed threshold language on p. 1-13)? and/or replaced impervious surface or 1. Projects containing or adjacent to a flood, erosion, or steep slope ~35,000 sf of new pervious surface? hazard area or documented drainage problem; projects within a landslide hazard area or landslide hazard drainage area; or No projects that propose ~7,000 sf (1 ac if project is in Small Project -Drainage Review} of land disturbing activity. 2. Projects proposing to construct or modify a drainage pipe/ditch that is 12" or larger or receives runoff from a 12" or larger drainage pipe/ditch. Yes No/ Yes i Reassess whether :. ·••··. ··if'<;~· drainage review is r~1tfl*•Jlt& ·,e;. required per Section •.: .. _· . '"-,,:; _,, : f,( . ~_:.,,; _;-.·. 1.1.1 (p. 1-8). . .; ·.· I ·I Does the project result in ;;;:50 acres of new impervious ~=~~ surface within a subbasin or multiple subbasins that are No hydraulically connected? ;:;,.· ; . · .. ·''{:. ',. Yes 1.jn~ I• ,, ···: · ___ . . ·,\·;; : . -. • ,; :: ' /Ci:' .. City of Renton 2009 Surface Water Design Manual Amendment 1-10 This page intentionally left blank. 1 • • •1 ProjectArea I,, • • I c::J Task 2 Study A rea c::J Task 3 , 4 , and 5 St udy Area ~ Pa rcel ~ Boun d a ry Contours - 10 ft I nterval Approx imate Ii ~~ D rai nage P at h ~ Wetla nd Hazard Area """ ~ f D Steep Slope Is,, ~ D E rosion ...Q t.\11 ~ l_J La ndsl ide A 1-)~ Note : Task 2 St udy A rea Inclu des t he D ownste ram Flow P ath 1 M ile D ownst ream of t he P roject A rea Tasks 3 through 5 P roj ect A rea I ncludes th e Do w nstream Fl ow P ath 1 /4 M ile Downst ream of t he P roj ect A rea PllliTH: Q:\PA.OJICTStWASHINGTON#UOl!T_SOUNO_!N! .. O'l'_OOT02l\TALBOT_STOftMWAT!:l'\_SU"'°l'tT_2HHI\MAP _OOCS"°"Al'TITlfl FIQIUl'l:lSU'IGUR!_I _OFFS IT(_ANALTSIS.MXD · USER: TAHOFJIMA • DAT£: 1111'1201$ OFFSITE ANALYSIS FIGU R E 6 STORMWATER TIR Technical Information Report Talbot Substation Stormwater Support 4 Flow Control and Water Quality Facility Analysis and Design 4.1 Existing Site Hydrology The existing condition hydrologic analysis assumed that stormwater runoff within the project area was confined to one subbasin which drains to the depression located on the southwestern corner of the project area. Drainage characteristics of the site are discussed in greater detail in Section 1.1.2 of this report. Subbasin area and drainage characteristics can be seen on Figure 7. Existing land cover is primarily yard rock with electrical equipment foundations throughout the site. Existing hydrology was calculated based on a pre-developed forested condition as the project area is located within a designated Flow Control Area per Reference 11-A of the COR SWDM (Appendix D). Existing condition peak flow values were calculated using the KCRTS modeling software. Existing acreage input to the KCRTS model and model results can be found in Table 1, below. Table 1: Existing Condition Acreage and Peak Flow Values Pre-Developed Forested 5.89 Acres Condition Area Peak Flow Event Discharge (CFS) 2-Year 0.16 5-Year 0.28 10-Year 0.29 25-Year 0.37 SO-Year 0.44 100-Year 0.48 4.2 Proposed Site Hydrology Changes to the existing land cover include removal of existing electrical equipment and the addition of new concrete equipment foundations, placement of new yard rock within the facility, and addition of a new stormwater detention pond (Figure 8). The yard rock is considered a partially impervious surface while all other improvements are considered impervious surfaces. Per Table 3.2.2.E in the 2009 KCSWDM, yard rock (gravel) surfaces must be multiplied by an effective impervious fraction of 0.50 to determine the impervious percentage of yard rock (gravel) surfaces. The remaining fraction is considered pervious. 8 I November i6, 2016 This page intentionally left blank. t LEGEND 1 Project Area __ 1 Subbasin Bou nda ry c::':!.( ~-};;) Contours - 5 ft I nterval Ponded Water Observed Duri ng Fie ld Visit Drainage Infrastructure Approximate II llli"~ Dra i nage Path 0 Drainage Path Roads & Feet 200 1-)~ PATH: O:'IPROJECTS'.WA$MINQTON\PUQU_sooNO_EHEROY _0070UITAl 8 01_STORMWATEl'\_IUPPO"T-2HtH\M,I.P _OOCS'.Oll:A,T'IT~ flOUftl!S\SIT!_HYOll:OLOGYMXO • USER . TA HOFFMA • OAff: 1111 11201, EXISTING SITE H YDRO LOGY FIGURE 7 STORMWATER TI R Technical Information Report L "\"\ Talbot Substation Stormwater Support r .,, Proposed condition peak flow values were calculated using the KCRTS modeling software. Proposed acreage input to the KCRTS model and model results can be found in Table 2 below. Table 2: Proposed Condition Acreage and Peak Flow Values Proposed Condition 5.89 Acres Area Peak Flow Event Discharge (CFS) 2-Year 1.11 5-Year 1.20 10-Year 1.34 25-Year 1.44 SO-Year 1.98 100-Year 2.25 4.3 Performance Standards The project area is located within a designated Flow Control Area per Reference 11-A of the COR SWDM (Appendix D) and is subject to the Flow Control Duration Standard for forested conditions. No drainage problems have been identified within the limits of the offsite analysis (discussed in detail in Section 3), so proposed conditions must match the flow durations for pre-developed, forested rates over the range of flows from 50% of the 2-year up to the full 50-year per Table 1.2.3.A of the COR SWDM (COR SWDM, 2009). Flow control facilities are required, as the project contains greater than 2,000 square feet of new plus replaced impervious surface. In Flow Control Duration Standard areas, these facilities must mitigate for target surfaces including: • New impervious surface that is not fully dispersed, • New pervious surface that is not fully dispersed, • Replaced impervious surface that is not fully dispersed on a parcel redevelopment project in which the total of new plus replaced impervious surface is 5,000 square feet or more. November 16, 2016 I 9 This page intentionally left blank. f-~~,.,... .... ~ LEGEND Project A rea ~ 1 ___ 1 Subbasin Boundary I Contours -~ 5 ft Interval f Drainage ! Infrastructu re Approximate llii"~ Dra i nage Path Dra i nage Path Roads c-z._ Proposed (___,/ Detention Pond A Feet 200 1-)~ PROPOSED S IT E HY DRO LO GY ~ F IGURE 8 NTH: Q '.PROJt:CT$tWA.SHNGTON\PUGET_SOUNO_l:NE.RCY_0010U\TA.LIOT_STOIUIIWAT!R_SUP9'0RT_MUU\MAP_OOC::S'MA,T\T" f'IOUMS\SITl!_HYDl'IOLOOVtUO · USU{: TAHO FFMA • OATII!: 1111tl?011 STORMWATER TIR Technical Information Report Talbot Substation Stormwater Support Flow control facilities and design are discussed in detail in Section 4.4. The NPGIS and pervious areas in Table 3 reflect the division of area covered by yard rock. Table 3: Existing and Proposed Land Use Summary Impervious Pervious Total NPGIS PGIS Existing 3.33 0.00 2.56 5.89 New 0.50 0.00 0.00 0.50 Replaced 3.33 0.00 2.06 5.39 Percent 65% Impervious Flow control BMPs must be provided to either supplement the flow mitigation provided by flow control facilities or provide flow mitigation where flow control facilities are not required (SWDM, 2009). These BMPs must be selected as directed in Section 5.2 of the SWDM. The proposed project area must meet the large lot high impervious BMP requirements listed in Section 5.2.1.2 of the SWDM as the project area is larger than 22,000 square feet and the impervious surface coverage is greater than 45% of the project area. Figure 5.2.1.A Flow Chart for Determining Individual Lot BMP Requirements of the SWDM is shown in Figure 9 below. 1 O I November 16, 2016 SECTIOK 5.2 FLOW CO"ITROL BMP REQUIREMENTS FIGURE 5.2.1.A FLOW CHART FOR DETERMING INDIVIDUAL LOT BMP REQUIREMEI\TS Is the project on a site/lot I Yes Is it feasible and smaller than 22,000 square feet? I applicable to implement full Yes No further BMPs Apply one or more of the following to impervious area dispersion for the required. Note: ;;:.10% of site/lot for site/lot sizes <11,000 sf and .a 20% of roof area as per Any proposed site/lot for site/lot sizes betw"een 11,000 and 22,000 sf (For Section C.2.1? connection of roof projects located in critical aquifer recharge areas these No i downspouts to impervious area amounts double): local drainage 1. Limited Infiltration (Section C.2.3) Is it feasible system must be 2. Basic Dispersion (Section C.2.4) via perforated 3. Rain Garden (Section C.2.5) and applicable pipe connection 4. Permeable Pavement (Section C.2.6) No to implement Yes per Section 5. Rainwater Harvesting (Section C.2.7) full infiltration C.2.11. No 6. Vegetated Roof (Section C.2.8) of the roof 7. Reduced Impervious Service Credit (Section C.2.9) runoff as per 8. Native Growth Retention Credit (Section C.2.10) Section C.2.2? I s me pr0Jec1 on a s,u,,nOt ...... ,uuu square 1eet Yes Is it feasible and or larger with impervious surface coverane of 45% or less? applicable to implement full dispersion on all Yes target impervious No further BMPs surface as per required. Note: One or more of the following BMPs must be implemented Section C.2.1? Any proposed connection of roof No for that portion of target impervious surface not addressed No+ downspouts to local with full dispersion or with full infiltration of roof runoff: drainage system 1. Full lnflltratlon (Section C.2.2 or Section 5.4) Is it feasible and applicable to must be via 2. Limited Infiltration (Section C.2.3) No implement full lnflltratlon of perforated pipe 3. Basic Dispersion (Section C.2.4) the roof runoff as per connection per 4. Rain Garden (Section C.2.5) Section C.2.2 or Section 5.4? Section C.2.11. 5. Permeable Pavement {Section C.2.6) Yes res T 6. Rainwater Harvesting (Section C.2.7) _J 7. Vegetated Roof (Section C.2.8) +------Is there any remaining target 8. Reduced Impervious Service Credit (Section C.2.9) impervious surface not 9. Natlve Growth Retention Credit tSection C.2.10\ addressed with full dispersion or I with full infiltration of roof runoff? The project must be a site/lot 22,000 square feet Is it feasible and or larger with impervious surface applicable to implement coverage of more than 45%? full dispersion on all target impervious No surface as per Projects with impervious area greater than 45% and equal to or Section C.2.1? less than 65% one or more of the following must be applied to an Yes i impervious area greater than or equal to 20% of the site or 40% of the target impervious surlace whichever is less OR for projects greater than 65% impervious one or more of the following must be No further BMPs applied to an impervious area greater than or equal to 10% of site required. Note: or 20% of target impervious surface, whichever is less: Any proposed 1. Full Infiltration (Section 5.4) connection of roof 2. Limited Infiltration (Section C.2.3) downspouts to 3. Basic Dispersion (Section C.2.4) local drainage 4. Rain Garden (Section C.2.5) system must be 5. Permeable Pavement (Section C.2.6) via perforated 6. Rainwater Harvesting (Section C.2.7) pipe connection 7. Vegetated Roof (Section C.2.8) per Section 8. Reduced Impervious Service Credit (Section C.2.9) C.2.11. 9. Native Growth Retention Credit {Section C.2.1 O) 1/9/2009 2009 Surface Water Design Manual 5-12 Technical Information Report L """' Talbot Substation Stormwater Support r ..,/~ The following list discusses each flow control BMP and its feasibility at the project area. • Full Infiltration o The project area lies over fill materials which are not suited for infiltration BMPs. • Limited Infiltration o The project area lies over fill materials which are not suited for infiltration BMPs. • Basic Dispersion a Existing topography on the northern and eastern edges of the project area forms high ground and prevents stormwater runoff from exiting the site. These higher areas would also restrict the vegetated flow path of a basic dispersion BMP to several feet, below the acceptable value. The eastern side of the project area is within the substation and bordered by yard rock not suitable for dispersion BMPs as there is no vegetated flow path and discharging stormwater within a substation is not recommended. • Rain Garden a There is no space available within the project area for a rain garden. The projects natural discharge location is located on the southern edge of the project area, and the proposed stormwater detention pond which has been designed to mitigate for all target surfaces within the project area lies in that location. Existing topography surrounding the northern and eastern edges of the site prevents placement of a rain garden in these locations, and a rain garden could not be placed on the western edge of the project area within the substation fence. • Permeable Pavement o No major paving activities are being proposed at the project area. • Rainwater Harvesting o The control house is the only structure with a roof that lies inside the project area. Storage of rainwater associated with a rainwater harvesting facility within the fence line of the substation is not feasible. There is also no use for harvested rainwater at the project site, no plants require irrigation and there are no facilities which may use harvested water. • Vegetated Roof o Vegetated rooftops within substation facilities are not feasible as the required maintenance would involve getting on top of or near the top of the roof surface in close proximity to high voltage power facilities. November 16, 2016 I 11 Technical Information Report Talbot Substation Stormwater Support • Reduced Impervious Surface Credit o Impervious surfaces have been restricted to the maximum extent feasible. Permeable yard rock is being used where vehicle access is not required within the substation fence. Impervious surfaces within the project area include the proposed stormwater detention pond, electrical and SPCC facilities, and the access road required for vehicles. • Native Growth Retention Credit o There are no native growth areas located within the project area. The proposed flow control facility will mitigate for all target surfaces at the project area. Proposed conveyance systems must be designed to convey the 25-year peak flow event with a minimum 6 inches of freeboard to the structure grate. Developed conditions must be assumed for onsite tributary areas, while existing conditions shall be assumed for offsite tributary areas. For events greater than the 25-year peak flow, structures may overlap. However, the 100-year peak flow event may not create or exacerbate any existing severe flooding or erosion problem per Core Requirement #2 of the COR SWDM. All overflows for peak flow events up to and including the 100-year event must discharge to their natural discharge location at the project area. Stormwater water quality treatment facilities are not required at the project area as the total area of pollution-generating surfaces is below the water quality requirement thresholds. SPCC structures will be installed around electrical components requiring oil in order to prevent stormwater contamination in the event an oil spill. These are the only water quality facilities which will be present at the project site. 4.4 Flow Control System An illustrative sketch of the proposed stormwater detention facility can be found below (Figure 10). KCRTS output containing "Compare Flow Duration" files and other model results can be found in Appendix E. While there are landslide hazard areas adjacent to the project, the project is not located within those areas and therefore is not required to use a safety factor when designing the stormwater detention facility (SWDM, 2009). Table 4 below compares the pre-developed condition discharge to the proposed condition site discharge from the flow control facility. Table 4: Pre-developed and Proposed Controlled Flow Comparison Peak Flow Discharge (CFS) Event Existing Proposed from Flow Control Facility 2-Year 0.16 0.09 5-Year 0.28 0.26 10-Year 0.29 0.28 25-Year 0.37 0.36 SO-Year 0.44 0.82 100-Year 0.48 1.04 12 I November 16, 2016 ' i ---------------,.,,- ,/ / / // ' ! I ~ C z ~ 1- . C>Q-' ~ ! ' ,, SJc; 0 ·..C. z . C 00 0 + C i j=! m --I J ~ 1 9 ~ s,., j • ..J ' "'!'? t -..-I I fa It< ,j " w I .J) \ ..j I -,-., -r. I i 9J -..j "1'.°". -,- ::r-r s -· (:,.. -"" 1 "' .s~ IL> <J\ b f S:!- ""' -~ ~ ...... ,.., ., s r 1R Q_ } "' ''; + "' ~ J (\ ' i~;·: I· , Ii [ .c.+ I -. a,l,£1 I . II.I J;Yl;I t = tfl'h t "P.., .... vs I> .., ' mo -(1) -I (/J ci:i' :, This page intentionally left blank. Technical lnfonnation Report I-)"\ Talbot Substation Stormwater Support ~ 4.5 Water Quality System As mentioned above, stormwater water quality facilities are not required. SPCC facilities will be placed where necessary. 5 Conveyance System Analysis and Design During field observations, two four-inch outlet pipes and catch basins were observed at the project area within the substation fence line at the northern and southern edges of the substation. No further analysis was performed on the existing conveyance system. The proposed stormwater conveyance system was designed to meet the conveyance requirements discussed in Section 4.3 of this report and was analyzed using the Rational Method and XP-SWMM. The Rational Method was used to assess the capacity of the pipes within the conveyance system as required by the 2009 SWDM. XP-SWMM was then used to demonstrate that the pipe system structures contain the hydraulic grade line for the 25-year rainfall event as required by the 2009 SWDM. The Rational Method conservatively calculates runoff flows based on basin area, rainfall intensity, and a runoff coefficient specific to land cover. Runoff flows into each catch basin were calculated for the 25-year event, and a water balance was performed to estimate the flows which would need to be conveyed in each pipe. When the flows were compared to the proposed conveyance system design pipe capacities, all proposed pipes were sized appropriately to convey the 25-year event flows. In XP-SWMM, conveyance system pipes were designed and modeled as 8-inch or 12 inch high density polyethylene (HOPE) pipe or perforated PVC pipe. Catch basins in the conveyance system were either Type 1 or type 1 L. The conveyance system was designed to route runoff from the substation, SPCC curb areas, and control house roof toward the south side of the substation, where a pipe outfalls to the proposed detention pond. Slopes of all proposed pipes in the conveyance system were modeled as 0.5%. Compliance with the requirements discussed in Section 4.3 was assessed by routing 25- and 100-year rainfall events through the XP-SWMM model. During the 25-year event, all structures appeared to maintain over 6 inches of freeboard in the model. Additionally, the hydraulic grade line was contained within the conveyance pipes. The conveyance system did not flood during the 100-year event. Model output can be found in Appendix E. 6 Special Reports and Studies No special reports or studies have been prepared for this project. 7 Other Permits Table 5 below lists additional permits required for the project area and their effects on the stormwater design. November 16, 2016 I 13 Technical Information Report Talbot Substation Stormwater Support Table 5: Additional Project Permit Requirements Permit Agency Effects on Stormwater Design TBD TBD TBD TBD TBD TBD 8 CSWPPP Analysis and Design A CSWPPP has been developed for the project and is located in Appendix F. 8.1 ESC Plan Analysis and Design The following ESC best management measures will be employed at the project area, as shown on the TESC plans and discussed in the CSWPPP: 8.1.1 Clearing Limits 8.1.2 8.1.3 To protect adjacent properties and reduce the volume of soil exposed to construction, construction limits will be clearly marked where necessary before construction begins. The construction of the proposed stormwater detention pond and paving of a small portion of the existing access road will be the only ground disturbing activity occurring outside of the substation fence. Natural vegetation and topsoil at the project area shall be retained to the maximum extent feasible. High visibility fence and silt fence BMPs will be used around the perimeter of the project area so that disturbance is kept to a minimum outside the work area. Cover Measures As the project is located west of the Cascade Mountain Crest, no soils shall remain exposed and unworked for more than seven days during the dry season (May 1 to September 30) and two days during the wet season (October 1 to April 30). Between these times, exposed soils stored aboveground shall be protected with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. Regardless of time, all soils shall be stabilized at the end of the shift before a holiday or weekend, and if needed, based on weather forecasts. Any areas expected to remain unworked for greater than 30 days must be seeded or sodded (King County, 1998). During the wet season, soil stockpiles with slopes greater than or equal to 3H:1 V, or with over ten feet of vertical relief must be covered if they will remain unworked for over 12 hours. During the wet season sufficient cover materials to stabilize all disturbed areas must be stockpiled on site, and the Wet Season Provisions of Section D.5.S of the King County Erosion and Sediment Control Standards must be followed (King County, 1998). Permanent stabilization will be achieved by placement of yard rock within the substation, and seeding at the proposed stormwater detention pond.· Perimeter Protection Vegetation and slope characteristics vary within the project area. The eastern edge of the project area is elevated and there is no risk contaminated stormwater will exit the project site in that area. The proposed stormwater detention pond and its outlet structure will be installed along the southern edge of the project area. Silt fence will be installed in this area to ensure no contaminated stormwater exits the project area. Silt fencing will 14 ] November 16, 2016 8.1.4 8.1.5 8.1.6 8.1.7 8.1.8 8.1.9 Technical Information Report 1-)"" Talbot Substation Stormwater Support ~ extend along the existing access road to its intersection with Puget Drive Southeast to prevent sediment generated from the proposed paving activities from exiting the project site. Concrete will be poured on site for proposed electrical equipment foundations within the substation. All concrete at the project area will be handled such that no cementitious material will enter stormwater runoff. Handling procedures are detailed on the TESC plans. Traffic Area Stabilization The project area will be accessed from the existing access road located on the southern edge of the substation. This access road is a stabilized surface and does not require additional stabilization. Proposed stormwater detention pond construction and access road paving will occur from the existing access road. Sediment Retention The proposed stormwater detention pond will be retrofitted as a temporary sediment storage facility for the duration of the project. All open grate catch basins and inlets located at the project area will be protected with storm drain inlet protection in order to prevent sediment contamination from entering the conveyance system. The sediment pond must have adequate surface area as defined in Section D.4.5.2 of the King County Erosion and Sediment Control Standards (King County, 1998). Required Pond Surface Area at top of Riser -SA= 2 x 0 2/0.00096 Proposed 2-year Peak Flow -0 2 = 0.092 Required SA= 192 Square Feet Provided Surface Area: -16,000 Square Feet Surface Water Collection Outlet protection will be installed at the outlet of the proposed stormwater detention pond before stormwater is routed through the facility. Dewatering Control Dewatering is not anticipated at the project site, as groundwater was not encountered during field activities performed by GeoEngineers (GeoEngineers, 2016). Dust Control Wind transport of soils is not anticipated at the project site. Exposed soils will be stabilized and will not remain exposed for long periods. Flow Control The project area triggers Core Requirement #3: Flow Control. The proposed stormwater detention pond will be retrofitted to serve as a sediment pond during construction. During this period, the hydraulic control structure and pond will continue to function as flow control facility's and restrict flow rates exiting the site to acceptable limits. November 16, 2016 I 15 Technical Information Report Talbot Substation Stormwater Support 8.2 CSWPPP Plan Design The following ESC best management measures will be employed at the project area, as shown on the TESC plans and discussed in the CSWPPP: • High Visibility Plastic Fence o High visibility plastic fence will be used around the perimeter of the substation and access road to clearly mark the proposed limits of construction. This will prevent unnecessary disturbance of existing vegetation and soils. • Silt Fence o Silt fence will be placed along the southern border of the existing access road to prevent sediment contaminated stormwater generated from the construction of the proposed stormwater detention pond and paving of the existing access road from exiting the project site. Silt fence will also serve to delineate the construction limits on the southern boundary of the project area • Temporary Sediment Pond o The proposed stormwater detention pond will be retrofitted as a temporary sediment pond. It will serve to retain sediment generated within the substation fence by placement of the proposed foundations, yard rock, and electrical components. The sediment pond will prevent sediment from exiting the project area. Sediment retention facilities are required whenever the project area exceeds three acres. Flow control is also required for the project, and the proposed stormwater detention pond will continue to regulate outflows through its control structure while it is being used as a temporary sediment retention facility. • Catch Basin Insert o Catch basin inserts will be placed on all catch basins within the substation fence line. They will be used to prevent sediment generated by work within the substation fence line from entering the proposed stormwater conveyance system and being transported downstream. • Outlet Protection o Outlet protection will be used at the outlet of the proposed stormwater detention pond. It will prevent scouring and erosion due to stormwater discharges exiting the pond. This is a permanent BMP which will be retained in place after construction is complete. Updates to the SWPPP may be requested by King County at any time during project construction if the County determines that pollutants generated on the construction site have the potential to contaminate surface, storm, or ground water. 16 I November 16, 2016 Technical Information Report L Ill\~ Talbot Substation Stormwater Support r .I~ 9 Bond Quantities, Facility Summaries, and Declaration of Covenant 9.1 Bond Quantities Worksheet The Bond Quantities Worksheet is located in Appendix G. 9.2 Flow Control and Water Quality Facility Summary Sheet and Sketch The Flow Control and Water Quality Facility Summary Sheet and Sketch is located in Appendix G. 9.3 Declaration of Covenant for Privately Maintained Flow Control and WQ Facilities Declaration of Covenant is not required for proposed privately maintained flow control facilities. 9.4 Declaration of Covenant for Privately Maintained Flow Control BMPs There are no flow control BMPs present at the project area. 10 Operations and Maintenance Manual A copy of the Operations and Maintenance Manual, along with the Maintenance Requirements for Flow Control, Conveyance, and WO Facilities is located in Appendix H. 11 References City of Renton. (201 OJ. City of Renton Amendments to the King County Surface Water Design Manual. Renton: City of Renton. King County. (2009). Surface Water Design Manual. Seattle: King County . November16,2016 I 17 This page intentionally left blank. Appendix A FEMA Firmette This page intentionally left blank. • ~-·-··----------- ! ' t' ~-'---1----+~"-+~~!--=·---j-~~"t-="---1-="--~-·~· l ~~--'--"'~I----~ ~.~ 1 I I ' ' ·r~ q htH r :; Ill ;; ,.,,..~,,,.,..,,,.,,,,," "'"'""""",,,.,, • ....,,I •mo """' l!W'>G>': -~----.,-----___ -~-=-=---~---=-~ ----~-=----=--~-~- M~ 11~ !5 !,!~~ 6:!! ,ji; I;, ,~ 8~o a ,a :r-;s ;:1: ,~ ~zo la !~ ~~; i: ! l z ~H ~ "t iii n' :~ I" I~ ! m ii I llJ I H • 0 ,, ~ •0 r -~ 0 z ~, .... ...,,,.,,, --· --·-·---------- I ; ,~,: • \ ' i \1,-------_Ji • L. 'I 1 k'I ~ s ! ,;,I ~ X - ' 0 I 11 ,1 -, ' Appendix B Drainage System Table 2009 Surface Water Design Manual KII\G COUNTY, WASHINGTON, SURFACE WATER DESIGN MAI\CAL KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-B OFFSITE ANALYSIS DRAINAGE SYSTEM TABLE 1/9/2009 Basin: Duwamish River Symbol Drainage Component Type, Name, and Size see map Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter, surface area Pink Fill Blue Fill Yellow Fill OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Subbasin Name: Project Area Subbasin Number: 1 Drainage Slope Distance Existing Potential Observations of field Component from site Problems Problems inspector, resource Descriotion discharae reviewer, or resident drainage basin, vegetation, % 14 ml= 1,320 ft. constrictions, under capacity, ponding, tributary area, likelihood of problem, cover, depth, type of sensitive overlapping, flooding, habitat or organism overflow pathways, potential impacts area, volume destruction, scouring, bank sloughing, sedimentation, incision, other erosion Landslide Hazard Adjacent None documented Increased None observed erosion and Erosion Hazard Adjacent None documented bank failure risk None observed Steep Slope Adjacent None documented None observed 11912009 Appendix C Site Photographs This page intentionally left blank. Site Photos January 18th, 2016 • Ponded water along eastern edge of site. • Ponded water along northwestern edge of site. 1 • Elevated field located off of the eastern edge of the substation, looking south. --~ -l • Elevated area along northern edge of substation, looking west. --·-- • Culvert outletting from south end of substation into • Local depression along southern edge of substation (site of proposed stormwater detention pond). • Local depression located along substation discharge path off the southwest corner of the substation. • Typical mountain bike path through downstream drainage area. • 4" Culvert passing beneath mountain bike path. • Looking south towards Grant Avenue South. i • Looking north towards substation, along drainage path. ~ .,. .. / This page intentionally left blank. Appendix D Reference 11-A Flow Control Areas Reference 11-A SE 72nd St Lake Washington '\ 91-405FWY (f) Q) > <{ .c ~ CX) .c a5 r SE 60th St , Pan t her Lake Newcastle Way ~ ( J~ ,v .p~ Flow Control Standards CJ Pe ak Rate Flow Contro l Standard (Existing Site Conditions) ~ Flow Contro l Du ration Standa rd (Ex isting Site Conditions ) Flow Control Du ration Standard (Forested Cond itions) 1111 Flood Problem Flow CJ Unincorporated King County Flow Control Standa rds --··-... L,._.! Renton City Lim its -·-·, L._.J Potential Annexation Area \ ~ \ w '1'19/)I, -----.J' ( ~ 0r; Issa quah ~) <{ Lake Youngs \ \ \ Flow Control Application Map Date: 01/09/2014 l W~E ~ s 0 2 --===:..-====------• Miles 1 Appendix E Stormwater Model Output This page intentionally left blank. KCRTS Pre-developed and Developed Duration Comparison Predeveloped and Developed Duration Comparison Duration Comparison Analysis Base File: psetalbotpredev 020816.tsf New File: pserdout 020816.tsf Fraction of Time Check of Tolerance Cutoff Base New % Change Prob Base New % Change (CFS) 0.081 0.0095 0.0067 -29.5 0.0095 0.081 0.078 -4.6 0.104 0.0063 0.0056 -10.4 0.0063 0.104 0.087 -16.0 0.126 0.0050 0.0053 5.9 0.0050 0.126 0.132 4.4 0.148 0.0037 0.0038 3.1 0.0037 0.148 0.151 1.9 0.171 0.0029 0.0025 -11.9 0.0029 0.171 0.165 -3.4 0.193 0.0022 0.0018 -19.9 0.0022 0.193 0.178 -7.8 0.215 0.0015 0.0011 -23.9 0.0015 0.215 0.202 -6.0 0.237 0.0010 0.0007 -31.7 0.0010 0.237 0.221 -7.0 0.26 0.0006 0.0005 -15.8 0.0006 0.260 0.250 -3.8 0.282 0.0003 0.0004 4.8 0.0003 0.282 0.285 1.2 0.304 0.0002 0.0003 14.3 0.0002 0.304 0.316 3.9 0.326 0.0002 0.0002 20.0 0.0002 0.326 0.337 3.2 0.349 0.0001 0.0001 -28.6 0.0001 0.349 0.348 -0.2 0.371 0.0000 0.0000 -100.0 0.0000 0.371 0.363 -2.3 Maximum positive excursion = 0.008 cfs (6.7%) occurring at 0.120 els on the Base Data (psetalbotpredev_020816.tsf) and at 0.128 els on the New Data (pserdout_020816.tsl). Maximum negative excursion= 0.019 els (-19.0%) occurring at 0.099 els on the Base Data (psetalbotpredev_020816.tsf) and at 0.080 els on the New Data (pserdout_020816.tsf). KCRTS Pond Design Results KCRTS Retention/Detention Facility Summary Relention/Dete~tion Facil~ty Type of Facility: Detention Pond Side Slope: 2.00 H: lV Pond Bottom Length: 241.81 ft Pond Bottom Width: 27.00 ft Pond Bottom Area: 6529. sq. ft Top Area at 1 ft. FE: 16155. sq. ft 0 .371 acres Effective Storage Depth: 7.00 ft Stage O Elevation: 425.50 ft Storage Volume: 73876. cu. ft 1. 696 ac-ft Riser Head: 7.00 ft Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.15 0.095 2 4.85 2 .13 0.180 6.0 3 6.10 2.00 0.103 4. 0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 425.50 0. 0.000 0.000 0.00 6529. 0.01 425.51 65. 0.001 0.004 0.00 6540. 0.02 425.52 131. 0.003 0. 0 06 0.00 6551. 0.04 425.54 262. 0.006 0.007 0.00 6572. 0.05 425.55 328. 0.008 0.008 0.00 6583. 0.06 425.56 394. 0.009 0.009 0.00 6594. 0.07 425.57 460. 0. 011 0.010 0.00 6604. 0.08 425.58 526. 0.012 C.010 0.00 6615. 0.10 425.60 658. 0.015 0. 011 0.00 6637. 0.23 425.73 1530. 0.035 0.017 0.00 6 777. 0.37 425.87 2490. 0.057 0.022 0.00 6929. 0.:) ~ 426.01 3470. 0.080 0.026 0.00 7082. 0.64 426.14 4400. 0.101 0.029 0.00 722,. 0.78 426.28 542?. 0 .124 0.032 0.00 7377. 0.92 426.42 6466. 0.148 0.034 0.00 7532. 1. 06 426.56 7531. 0 .173 0. 037 0.00 76 8 7. 1.19 426.69 8540. 0 .196 0.039 0.00 7831. 1. 33 426.83 964 7. 0.221 0.041 0.00 7987. 1. 4 7 426.97 10776. 0.247 0 .043 0.00 8144. 1. 61 427.11 11928. 0.274 0.045 0.00 8302. 1. 74 427.24 13016. 0.299 0.047 0.00 8448. 1. 88 427.38 14210. 0.326 0.049 0.00 8607. 2.02 427.52 15426. 0.354 0.051 0.00 8766. 2.15 427.65 16576. 0.381 0.053 0.00 8915. 2.29 427.79 17835. 0.409 0.054 0.00 9075. 2.43 427.93 19117. 0.439 0.056 0.00 9236. 2.57 428.07 20 421. C.469 0.057 0.00 9398. 2.70 428.20 21653. 0. 49 7 0.059 0.00 9549. 2.84 428.34 23001. 0.528 0.060 0.00 9712. 2.98 428.48 24372. 0.560 0.062 0.00 9875. 3.12 428.62 25766. 0. 592 0.063 0.00 10040. 3.25 428.75 27081. 0.622 0.065 0.00 10193. 3.39 '28.89 28520. 0.655 0.066 0.00 10358. 3.53 429.03 29981. 0.688 0.067 0.00 10524. 3.66 429.16 31359. 0.720 0.069 0.00 10679. 3.80 429.30 32866. 0.755 0.070 0.00 10846. 3.94 429.44 34396. 0.790 0 .071 0.00 11014. 4.08 429.58 35950. 0.825 0 .072 0.00 11182. 4 .21 429.71 37414. 0.859 0.074 0.00 11339. 4.35 429.85 39013. 0. 896 0.075 0.00 11509. 4.49 429.99 40637. 0.933 0.076 0.00 11679. 4.63 430 .13 42284. 0. 971 0.077 0.00 11850. 4.76 430.26 43835. 1.006 0. 078 0.00 12010. 4.85 430.35 44920. l. 031 0.079 0.00 12120. 4.87 430.37 45163. 1. 037 0.080 0.00 12145. 4.89 430.39 45406. 1.042 0.084 0.00 12170. 4.92 430.42 45772. 1.051 0.090 0.00 12207. 4.94 430.44 46016. 1.056 0.098 0.00 12231. 4. 96 430.46 46261. 1.062 0.108 0.00 12256. 4.98 430.48 46507. 1. 06 8 0.120 0.00 12281. 5.00 430.50 46752. 1.073 0.128 0.00 12305. 5.03 430.53 4 7122. 1. 0 82 0.132 0.00 12342. 5. 05 430.55 47369. 1.087 0.135 0.00 12367. 5.19 430.69 49113. 1.127 0.153 0.00 12541. 5.32 430.82 50754. 1.165 0.167 0.00 12702. 5.46 430. 96 52544. 1. 206 0.180 0.00 12877. 5.60 431.10 54359. 1. 248 0.191 0.00 13052. 5.74 431. 24 56199. 1. 290 0.201 0.00 13228. 5.87 431.37 57929. 1. 330 0. 211 0.00 13392. 6.01 431.51 59816. 1. 373 0.220 0.00 13569. 6.10 431.60 61043. 1.401 0.226 0.00 13683. 6.12 431. 62 6131 7. 1.408 0.228 0.00 13709. 6.14 431. 6 4 61591. 1. 414 0.231 0.00 13734. 6.16 431.66 61866. 1. 420 0.237 0.00 13760. 6.18 431.68 62141. 1.427 0.244 0.00 13785. 6.20 431.70 62417. 1.433 0.252 0.00 13811. 6.23 431.73 62832. 1.442 0.262 0.00 13849. 6.25 431.75 63109. 1.449 0. 272 0.00 13874. 6.27 431. 77 63387. 1.455 0.280 o.oc 13900. 6.40 431. 90 65205. 1.497 0.303 0.00 14066. 6.54 432.04 67187. 1. 542 0.323 0.00 14246. 6.68 432.18 69194. 1. 588 0.341 0.00 14426. 6.82 432.32 71226. 1. 635 0.357 0.00 14606. 6.95 432.45 73136. 1. 6 79 0. 372 0.00 14 775. 7.00 432.50 73876. 1. 696 0.377 0.00 14840. 7.10 432.60 75367. 1. 730 0. 696 0.00 14970. 7.20 432.70 76870. 1.765 1. 270 0.00 15100. 7.30 432.80 78387. 1. 800 2.010 0.00 15231. 7.40 432.90 79916. 1. 835 2.810 0.00 15362. 7.50 433.00 81459. 1.870 3.100 0.00 15493. 7.60 433.10 83015. 1. 906 3.360 0.00 15625. 7.70 433.20 84584. 1.942 3.610 0.00 15757. 7.80 433.30 86167. 1. 978 3.830 0.00 15889. 7.90 433.40 87762. 2.015 4.050 0.00 16022. 8.00 433.50 89371. 2.052 4.250 0.00 16155. 8.10 433.60 90993. 2.089 4.440 0.00 16288. 8.20 433.70 92629. 2.126 4.630 0.00 16422. 8.30 433.80 94278. 2.164 4.800 0.00 16556. 8.40 433.90 95940. 2.202 4.970 0.00 16690. 8.50 434.00 97616. 2.241 5.140 0.00 16825. 8.60 434 .10 99305. 2.280 5.300 0.00 16960. 8.70 434.20 101008. 2.319 5.450 0.00 17095. 8.80 43C 30 102724. 2.358 5.600 8.0C 17230. 8.90 434.40 10445s. 2.398 5.750 0.00 17366. Hyd Inflow Outflow Peak Sto::age Target Cale Stage Elev (Cu-Ft) 1 2.25 0.47 1. 05 7.16 432.66 76281. 2 1.11 ******* 0.36 6.80 432.30 71008. 3 1.12 ******* 0.26 6.23 431.73 62802. 4 1.18 ******* 0 .17 5.37 430.87 51439. 5 l. 34 ******* 0.28 6 .27 431.77 63431. 6 0.70 ******* 0.09 4. 92 430.42 45833. 7 0. 91 ******* 0.08 4.57 430.07 41528. 8 0.99 ******* 0.07 3.37 428.87 28288. ---------------------------------- Route Time Series through Facility Inflow Time Series File:psetalbotdev_020816.tsf Outfiow Time Series File:PSErdout 020816 Inflow/Outflow Analysis Peak Inflow Discharge: 2.25 CFS at 6:00 on Peak Outflow Discharge: 1. 04 CFS at 10:00 on Peak Reservoir Stage: 7.16 Ft Peak Reservoir Elev: 432.66 Ft Peak Reservoir Storage: 76281. Cu-Ft 1.751 Ac-Ft (Ac-Ft) l. 751 :.630 1.442 1.181 1.456 1.052 0.953 0.649 Jan 9 in Jan 9 in Year 8 Year 8 KCRTS Pre-developed and Developed Stormwater Pond Flow Output Predeveloped Peak Flows and Flow Frequency Analysis from KCRTS Flow Frequency Analysis Time Series File: psetalbotpredev 020816.tsf Project Location:Sea-Tac I ' I ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks--Rank Return Prob (CFS) (CFS) Period 0.372 2 2/9/200118:00 0.475 1 100 0.99 0.101 7 1/6/2002 3:00 0.372 2 25 0.96 0.276 4 2/28/2003 3:00 0.285 3 10 0.9 0.010 8 3/24/2004 20:00 0.276 4 5 0.8 0.164 6 1/5/2005 8:00 0.241 5 3 0.667 0.285 3 1/18/2006 21:00 0.164 6 2 0.5 0.241 5 11/24/2006 4:00 0.101 7 1.3 0.231 0.475 1 1/9/2008 9:00 0.010 8 1.1 0.091 Computed Peaks 0.441 50 0.98 Developed Peak Flows and Flow Frequency Analysis before Stormwater Detention Pond from KCRTS Flow Frequency Analysis Time Series File: psetalbotdev 020816.tsf Project Location:Sea-Tac I I I ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks--Rank Return Prob (CFS) (CFS) Period 1.11 6 2/9/2001 2:00 2.25 1 100 0.99 0.912 8 1/5/2002 16:00 1.44 2 25 0.96 1.34 3 2/27 /03 7:00 1.34 3 10 0.9 0.992 7 8/26/2004 2:00 1.20 4 5 0.8 1.20 4 10/28/2004 16:00 1.18 5 3 0.667 1.18 5 1/18/2006 16:00 1.11 6 2 0.5 1.44 2 10/26/2006 0:00 0.992 7 1.3 0.231 2.25 1 1/9/2008 6:00 0.912 8 1.1 0.091 Computed Peaks 1.98 50 0.98 Proposed Peak Flows and Flow Frequency Analysis from Stormwater Detention Pond from KCRTS Flow Frequency Analysis Time Series File:pserdout 020816.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--------Flow Frequency Analysis------- Flow Rate Rank Time of Peak --Peaks--Rank Return Prob (CFS) (CFS) (ft) Period 0.363 2 2/9/2001 21:00 1.04 7.16 1 100 0.99 0.077 7 1/7/2002 4:00 0.363 6.87 2 25 0.96 0.281 3 3/6/2003 22:00 0.281 6.27 3 10 0.9 0.066 8 8/26/2004 7:00 0.261 6.23 4 5 0.8 0.092 6 1/8/2005 5:00 0.172 5.37 5 3 0.667 0.172 5 1/19/2006 0:00 0.092 4.92 6 2 0.5 0.261 4 11/24/2006 8:00 0.077 4.57 7 1.3 0.231 1.04 1 1/9/2008 10:00 0.066 3.37 8 1.1 0.091 Computed Peaks 0.818 7.12 50 0.98 This page intentionally left blank. KCRTS Pre-developed and Developed Flow Durations and Curve Predeveloped Flow Durations from KCRTS Flow Duration Time Series File: psetalbotpredev 020816.tsf Exceed a nee Cutoff Count Frequency CDF Probability CFS % % % 0.082 60744 99.061 99.061 0.939 9.39E-03 0.092 112 0.183 99.243 0.757 7.57E-03 0.103 72 0.117 99.361 0.639 6.39E-03 0.113 41 0.067 99.428 0.572 5.72E-03 0.123 40 0.065 99.493 0.507 5.07E-03 0.134 35 0.057 99.550 0.450 4.SOE-03 0.144 37 0.060 99.610 0.390 3.90E-03 0.154 27 0.044 99.654 0.346 3.46E-03 0.164 23 0.038 99.692 0.308 3.08E-03 0.175 22 0.036 99.728 0.272 2.72E-03 0.185 18 0.029 99.757 0.243 2.43E-03 0.195 17 0.028 99.785 0.215 2.lSE-03 0.206 23 0.038 99.822 0.178 1.78E-03 0.216 19 0.031 99.853 0.147 1.47E-03 0.226 12 0.020 99.873 0.127 1.27E-03 0.236 15 0.024 99.897 0.103 1.03E-03 0.247 13 0.021 99.918 0.082 8.15E-04 0.257 9 0.015 99.933 0.067 6.69E-04 0.267 9 0.015 99.948 0.052 5.22E-04 0.278 9 0.015 99.962 0.038 3.75E-04 0.288 5 0.008 99.971 0.029 2.94E-04 0.298 2 0.003 99.974 0.026 2.61E-04 0.309 3 0.005 99.979 0.021 2.12E-04 0.319 2 0.003 99.982 0.018 1.79E-04 0.329 1 0.002 99.984 0.016 1.63E-04 0.340 1 0.002 99.985 0.015 1.47E-04 0.350 4 0.007 99.992 0.008 8.15E-05 0.360 3 0.005 99.997 0.003 3.26E-05 0.370 1 0.002 99.998 0.002 1.63E-05 0.381 1 0.002 100.000 0.000 O.OOE+OO 0.391 0 0.000 100.000 0.000 O.OOE+OO 0.401 0 0.000 100.000 0.000 O.OOE+OO 0.412 0 0.000 100.000 0.000 O.OOE+OO 0.422 0 0.000 100.000 0.000 O.OOE+OO 0.432 0 0.000 100.000 0.000 O.OOE+OO 0.443 0 0.000 100.000 0.000 0.00E+OO 0.432 0 0.000 100.000 0.000 0.00E+OO 0.443 0 0.000 100.000 0.000 O.OOE+OO Developed Flow Durations from Stormwater Detention Pond from KCRTS Flow Duration Time Series File: psetalbotpredev 020816.tsf Exceed a nee Cutoff Count Frequency CDF Probability CFS % % % 0.005 30750 50.147 50.147 49.853 4.99E-01 0.015 6754 11.014 61.161 38.839 3.88E-01 0.026 5291 8.629 69.790 30.210 3.02E-01 0.036 5511 8.987 78.777 21.223 2.12E-01 0.046 4878 7.955 86.732 13.268 1.33E-01 0.056 3407 5.556 92.288 7.712 7.71E-02 0.066 2133 3.478 95.766 4.234 4.23E-02 0.077 1820 2.968 98.735 1.265 1.27E-02 0.087 390 0.636 99.371 0.629 6.29E-03 0.097 33 0.054 99.424 0.576 5.76E-03 0.107 11 0.018 99.442 0.558 5.58E-03 0.117 10 0.016 99.459 0.541 5.41E-03 0.128 10 0.016 99.475 0.525 5.25E-03 0.138 43 0.070 99.545 0.455 4.55E-03 0.148 43 0.070 99.615 0.385 3.85E-03 0.158 41 0.067 99.682 0.318 3.18E-03 0.168 31 0.051 99.733 0.267 2.67E-03 0.178 29 0.047 99.780 0.220 2.20E-03 0.189 20 0.033 99.812 0.188 1.88E-03 0.199 15 0.024 99.837 0.163 l.63E-03 0.209 21 0.034 99.871 0.129 l.29E-03 0.219 16 0.026 99.897 0.103 1.03E-03 0.229 15 0.024 99.922 0.078 7.83E-04 0.24 6 0.010 99.932 0.068 6.85E-04 0.25 4 0.007 99.938 0.062 6.20E-04 0.26 6 0.010 99.948 0.052 5.22E-04 0.27 4 0.007 99.954 0.046 4.57E-04 0.28 4 0.007 99.961 0.039 3.91E-04 0.291 6 0.010 99.971 0.029 2.94E-04 0.301 1 0.002 99.972 0.028 2.77E-04 0.311 2 0.003 99.976 0.024 2.45E-04 0.321 2 0.003 99.979 0.021 2.12E-04 0.331 3 0.005 99.984 0.016 l.63E-04 0.342 2 0.003 99.987 0.013 1.30E-04 0.352 3 0.005 99.992 0.008 8.15E-05 0.362 4 0.007 99.998 0.002 l.63E-05 This page intentionally left blank. ;;j' ~ ~ "' ~ " .c u 5 0.4 0.35 0.3 0.25 I 0.2 I 0.15 0.1 0.05 0 l.OOE-05 l.OOE-04 Flow Duration Analysis from KCRTS ~ --Developed Conditions ' --Predeveloped Conditions l.OOE-03 l.OOE-02 l.OOE-01 l.OOE+OO Probability Exceedence This page intentionally left blank. Rational Method Documentation Rational Method Rational Method Pipe Capacity Analysis 25-yr Flows (ds) 25-yr Capacity Analysis 100-yr Flows (cfs) Runoff from from Total Cumulative Pipe Full Flow Compliant Runoff from Runoff from Total Cumulative Subbasin 1mpervious Impervious Pervious Runoff Flow in Downstream Capacity from with Capacity Impervious Pervious Area Runoff Flow in Name Area (ft2 ) Area (ac) Area(%) Area (cfs) Area (cfs) (cfs) System (cfs) Pipe Name XPSWMM(ds) Requirement? Area (cfs) (cfs) (cfs) System ( cfs) CB10 1783.8 0.041 0.65 0.020 0.010 0.030 0.030 Link4 0.940 Yes 0.021 0.012 0.034 0.034 CB11 2272.8 0.052 0.65 0.025 0.013 0.038 0.068 Link5 0.940 Yes 0.029 oms 0.044 0.078 CB12 2504.3 0.057 0.65 0.028 0.014 0.042 0.110 Link6 0.940 Yes 0.032 0.016 0.048 0.126 CB13 2.124.6 0.053 0.65 0.026 0.013 0.039 0.149 Link7 0.940 Yes 0.030 0.015 0.045 0.170 Ci:H4 2243.2 0.051 0.65 0.025 0.013 0.038 0.186 Link8 0.940 Yes 0.029 0.015 0.043 0.213 CB15 2279.5 0.052 0.65 0.025 0.013 0.038 0.284 Link9 0.940 Yes 0.029 0.015 0.044 0.326 CB16 2101.l 0.048 0.65 0.023 0.012 0.035 0.319 LinklO 0.940 Yes 0.027 0.014 0.040 0.366 CtH7 2260.6 0.052 0.65 0.025 0.013 0.038 0.357 Link11 0.950 Yes 0.029 0.015 0.043 0.409 CB18 2388.4 0.055 0.65 0.026 0.013 0.040 0.397 Link12 0.940 Yes 0.030 0.015 0.046 0.455 C:B19 2%9.6 0.054 0.65 0.026 0.013 0.040 0.437 Link.13 0.910 Yes 0.030 0.015 0.045 0.501 CB20 2541.3 0.058 0.65 0.028 0.014 0.042 0.479 Link14 2.730 Yes 0.032 0.016 0.049 0.549 CB21 1809.5 0.042 0.65 0.020 0.010 0.030 0.509 Link15 2.710 Yes 0.021 0.012 0.035 0.584 C:B22 4239.4 0.097 0.65 0.047 0.024 0.071 0.071 Link19 0.940 Yes 0.054 0.027 0.081 0.081 CB23 7207 0.165 0.65 0.080 0.041 0.120 0.191 Link20 0.940 Yes 0.092 0.047 0.138 0.220 CB24 514.1.6 0.118 0.65 0.057 0.029 0.086 0.277 Link21 1.100 Yes 0.065 0.033 0.099 0.318 CU25 3582.3 0.082 0.65 0.040 0.020 0.060 0.337 Link22 0.950 Yes 0.046 0.023 0.069 0.387 CB26 5034.8 0.116 0.65 O.OS6 0.028 0.084 0.084 Link16 0.940 Yes 0.064 0.033 0.097 0.097 CB27 7103.4 0.163 0.65 0.079 0.040 0.119 0.203 Link17 0.940 Yes 0.090 0.046 0.136 0.233 Cl:328 4914.9 0.113 0.65 0.054 0.028 0.082 0.285 Link18 2.730 Yes 0.062 0.032 0.094 0.327 CB29 2539.3 0.058 0.65 0.028 0.014 0.042 2.571 Link54 2.730 Yes 0.032 0.016 0.049 2.950 CB30 4221.2 0.097 0.65 0.047 0.024 0.071 0.071 Link23 0.940 Yes 0.054 0.027 0.081 0.081 CB31 7300.1 0.168 0.65 0.081 0.041 0.122 0.193 Link.24 0.940 Yes 0.093 0.047 0.140 0.221 CB32 5210.8 0.120 0.65 0.058 0.029 0.087 0.280 Link25 0.940 Yes 0.066 0.034 0.100 0.3?1 CB33 3677.3 0.084 0.65 0.041 0.021 0.061 0.341 Link26 0.940 Yes 0.047 0.024 0.071 0.391 CB34 5122.1 0.118 0.65 0.057 0.029 0.086 0.086 Link.27 0.940 Yes 0.065 0.033 0.098 0.098 CB35 7241.6 0.166 0.65 0.080 0.041 0.121 0.207 Link28 0.940 Yes 0.092 0.047 0.139 0.237 Cl:336 5030.2 0.115 0.65 0.056 0.028 0.084 0.291 Link.29 2.730 Yes 0.064 0.033 0.096 0.334 CB37 2586.9 0.059 0.65 0.029 O.D15 0.043 1.735 Link30 2.730 Yes 0.033 0.Q17 0.050 1.990 CB38 5877.5 0.135 0.65 0.065 0.033 0.098 0.098 Link31 0.940 Yes O.D75 0.038 0.113 0.113 CB39 4688.8 0.108 0.65 0.052 0.026 0.078 0.232 Link32 0.940 Yes 0.060 0.030 0.090 0.266 CB40 3307.2 0.076 0.65 0.037 0.019 0.055 0.055 Link44 0.940 Yes 0.042 0.021 0.063 0.063 CB41 5186.1 0.119 0.65 0.057 0.029 0.087 0.319 Link33 0.940 Yes 0.066 0.034 0.099 0.365 CB42 3599.2 0.083 0.65 0.040 0.020 0.060 0.060 Link43 0.940 Yes 0.046 0.023 0.069 0.069 CB43 4345.9 0.100 0.65 0.048 0.024 0.073 0.864 Link34 2.110 Yes 0.055 0.028 0.083 0.992 CB44 3895 0.089 0.65 0.043 0.022 0.065 0.971 Link35 2.750 Yes 0.050 0.025 0.075 1.114 CB45 3795 0.087 0.65 0.042 0.021 0.063 1.210 Link37 2.730 Yes 0.048 0.025 0.073 1.388 CB46 2829 0.065 0.65 0.031 0.016 0.047 0.075 Link.41 0.940 Yes 0.036 0.018 0.054 0.086 CB47 1648.9 0.038 1 0.028 0.000 0.028 0.028 Link45 0.950 Yes 0.032 0.000 0.032 0.032 CB48 4692.4 0.108 0.65 0.052 0.026 0.078 1.336 Link38 2.730 Yes 0.060 0.030 0.090 1.533 CB49 2852.1 0.065 0.65 0.032 0.016 0.048 0.048 Link40 0.940 Yes 0.036 0.018 0.055 0.055 CB50 3854.1 0.088 0.65 0.043 0.022 0.064 1.401 Link39 2.730 Yes 0.049 0.025 0.074 1.607 CB51 2488.9 0.057 0.65 0.028 0.014 0.042 0.042 Link53 0.470 Yes 0.032 0.016 0.048 0.048 CB52 1505.1 0.035 0.65 0.017 0.008 0.025 0.025 Link48 0.470 Yes 0.019 0.010 0.029 0.029 CB53 1460.6 0.034 0.65 0.016 0.008 0.024 0.050 Link49 0.470 Yes 0.019 0.009 0.028 0.057 CS54 2481.8 0.057 0.65 O.D28 0.014 0.041 0.041 Link.52 0.470 Yes 0.032 0.016 0.048 0.048 CBSS 1492.6 0.034 0.65 0.017 0.008 0.025 0.050 Link51 0.470 Yes 0.019 0.010 0.029 0.057 CB56 1489.5 0.034 0.65 0.017 0.008 0.025 0.025 LinkSO 0.520 Yes O.D19 0.010 0.029 0.029 CB57 3437.5 0.079 0.65 O.D38 0.019 0.057 1.071 Unk36 2.730 Yes 0.044 0.022 0.066 1.229 C:B58 2562.5 0.059 0.65 0.028 0.014 0.043 0.043 Link42 0.940 Yes 0.033 0.Q17 0.049 0.049 GI-1 2475.2 0.057 0.65 0.027 0.014 0.041 0.133 Link47 1.030 Yes 0.031 0.016 0.047 0.152 GI-2 2440.2 0.056 0.65 0.027 0.014 0.041 0.132 Link46 1.030 Yes 0.031 0.016 0.047 0.151 Rational Method Coefficient 0.85 for gravel pavement 0.9 for pavement Rainfall Intensity (ft/s) 0.00002 for 25-yr 0.00002 for 100-yr This page intentionally left blank. XPSWMM Model Documentation XPSWMM XPSWMM Model Schematic CB10 CB11 CB12 CB13 CB14 CB15 CB16 CB17 CB18 CB19 CB20 CB21 Lin~ Linlf15 CB22 CB23 CB24 f.;B25 CB26 CB27 CB28 tCB29 Pond OF -~ CB30 CB31 CB32 CB33 CB34 CB35 CB36 unto CB37 CB38 CB39 CB.41 CB48 unlo CB49 ~ CB46, 1_" CB58 CB51 CB54 CB56 CB53 XPSWMM Catch Basin (Node) & Pipe (Link) Input Data link Input Data Summary Downstream Upstream Downstream Upstream Invert Invert Diameter Length Conduit link Name Node Name Node Name Elevation (ft) Elevation (ft) (ft) (ft) Slope (%) Roughness Link4 (810 (811 436.51 436.26 0.67 so 0.5 0.012 Links C811 CB12 436.26 435.96 0.67 60 0.5 0.012 Link6 CB12 CB13 435.96 435.66 0.67 60 0.5 0.012 Link7 CB13 CB14 435.66 435.41 0.67 50 0.5 0.012 Link8 C814 CB1S 435.24 434.92 0.67 64 0.5 0.012 Link9 CB15 CB16 434.S 434.27 0.67 46 0.5 0.012 Link10 CB16 CB17 434.27 434.02 0.67 so o.s 0.012 Link11 (817 CB18 434.02 433.73 0.67 57 0.5 0.012 Link12 CB18 CB19 433.73 433.48 0.67 50 0.5 0.012 Link13 CB19 C820 433.48 433.21 0.67 58 0.5 0.012 Link14 C820 C821 432.88 432.58 1 60 0.5 0.012 Link15 C821 C829 432.58 432.26 1 65 0.5 0.012 link54 C829 Pond 430.69 430.5 1 38 0.5 0.012 link18 C828 C829 435.13 434.83 1 60 0.5 0.012 Link17 C827 (828 435.77 435.23 0.67 108 0.5 0.012 Link16 C826 (827 436.42 435.87 0.67 110 0.5 0.012 Link22 CB25 CB15 434.94 434.6 0.67 67 0.5 0.012 Link21 C824 CB25 435.34 434.97 0.67 54 0.5 0.012 Unk20 (823 CB24 435.96 435.41 0.67 110 0.5 0.012 Link19 (822 CB23 436.51 435.96 0.67 110 0.5 0.012 Link30 CB37 (829 430.98 430.69 1 58 0.5 0.012 Link28 C835 (836 435.88 435.34 0.67 108 0.5 0.012 Link29 CB36 (837 435.01 434.71 1 60 0.5 0.012 Link27 CB34 CB35 436.42 435.88 0.67 108 0.5 0.012 Link39 CBSO CB37 431.36 430.98 1 76 0.5 0.012 Link38 CB48 CB50 431.66 431.36 1 60 0.5 0.012 Link37 CB45 CB48 432.53 431.99 1 108 0.5 0.012 Link36 CB57 CB45 434.11 433.81 1 60 0.5 0.012 Link35 CB44 CB57 434.44 434.11 1 65 0.5 0.012 Link34 CB43 CB44 434.54 434.45 1 17 0.5 0.012 Link33 CB41 CB43 435.49 435.12 0.67 74 0.5 0.012 Link32 CB39 C841 436.21 435.66 0.67 110 0.5 0.012 Link31 CB38 C839 436.51 436.21 0.67 60 0.5 0.012 Link26 C833 CB43 434.92 434.54 0.67 76 0.5 0.012 Link25 CB32 CB33 435.24 434.92 0.67 64 0,5 0.012 Link24 CB31 (832 435.96 435.41 0.67 110 0.5 0.012 Link23 C830 CB31 436.51 435.96 0.67 110 0.5 0.012 Link44 CB40 C839 436.45 436.25 0.67 40 0.5 0.012 Link43 CB42 (841 436.25 436.05 0.67 40 0.5 0.012 Link42 CBS8 (857 436 435.8 0.67 40 0.5 0.012 link40 CB49 (848 436 435.8 0.67 40 0.5 0.012 Link41 CB46 (845 432.75 432.6 0.67 30 0.5 0.012 Link45 CB47 (846 432.98 432.75 0.67 45 0.5 0.012 Link46 Gl-2 (843 435.21 434.79 0.67 83 0.5 0.011 Link47 Gl-1 (844 435.21 434.79 0.67 83 0.5 0.011 Link51 C855 Gl-1 435.93 435.71 0.5 43 0.5 0.011 LinkSO (856 CBSS 436.45 435.93 0.5 83 0.5 0.011 Link52 (854 Gl-1 436.25 435.84 0.5 83 0.5 0.011 Link49 C853 Gl-2 435.93 435.71 0.5 43 0.5 0.011 Link48 (852 CB53 436.45 436.03 0.5 83 0.5 0.011 Link53 C851 Gl-2 436.25 435.84 o.s 83 0.5 0.011 (link 55) riserweir Pond OF NA NA NA NA NA NA (Link 55) bottom orifice Pond OF NA NA 0.10 NA NA NA (Link 55) side#1 Pond OF NA NA 0.18 NA NA NA {Link 55) side#2 Pond OF NA NA 0.17 NA NA NA Node Hydraulic Input Data Invert Node Ground Elevation Elevation Name Spill Crest (ft) (ft) CB10 437.92 436.51 CB11 437.92 436.26 CB12 437.92 435.96 CB13 437.92 435.66 CB14 437.92 435.24 CB15 437.92 434.5 CB16 437.92 434.27 CB17 437.92 434.02 CB18 437.92 433.73 CB19 437.92 433.48 CB20 437.92 432.88 CB21 437.92 432.58 CB29 437.92 430.69 CB28 437.75 435.13 CB27 437.75 435.77 CB26 437.75 436.42 CB25 437.75 434.94 CB24 437.75 435.24 CB23 437.75 435.96 CB22 437.75 436.51 CB37 437.92 430.98 CB35 437.75 435.88 CB36 437.75 435.01 CB34 437.75 436.42 CB50 437.92 431.36 CB48 437.75 431.66 CB45 437.75 432.53 CB57 437.75 434.11 CB44 437.75 434.44 CB43 437.75 434.54 CB41 437.75 435.49 CB39 437.75 436.21 CB38 437.75 436.51 CB33 437.75 434.92 CB32 437.75 435.24 CB31 437.75 435.96 CB30 437.75 436.51 CB40 437.54 436.45 CB42 437.5 436.25 CB58 437.5 436 CB49 437.75 436 CB46 437.75 432.75 CB47 437.75 432.98 Gl-2 439.65 435.21 Gl-1 439.65 435.21 CB55 438.25 435.93 CB56 438.25 436.45 CB54 438.25 436.25 CB53 438.25 435.93 CB52 438.25 436.45 CB51 438.25 436.25 Pond 437.5 425.5 OF 437.5 425 Node Runoff Input Data Node Area Slope Impervious Name (ac) (ft/ft) Percentage(%) Width (ft) (810 0.041 0.003 65 43 CBll 0.052 0.003 65 55 CB12 0.057 0.003 65 60 CB13 0.053 0.003 65 55 (814 0.051 0.003 65 57 (815 0.052 0.003 65 54 CB16 0.048 0.003 65 49 CB17 0.052 0.003 65 52 CB18 0.055 0.003 65 55 (819 0.054 0.003 65 54 C820 0.058 0.003 65 58 C821 0.042 0.003 65 44 CB29 0.058 0.003 65 63 CB28 0.113 0.003 65 79 C827 0.163 0.003 65 113 CB26 0.116 0.003 65 80 CB25 0.082 0.003 65 63 C824 0.118 0.003 65 82 CB23 0.165 0.003 65 114 C822 0.097 0.003 65 67 CB37 0.059 0.003 67 64 C835 0.166 0.003 65 114 CB36 0.115 0.003 65 79 C834 0.118 0.003 65 80 CBSO 0.088 0.003 65 95 C848 0.108 0.003 65 79 CB45 0.087 0.003 65 69 C857 0.079 0.003 65 62.5 C844 0.089 0.003 65 95 (843 0.1 0.003 65 95 CB41 0.119 0.003 65 92 CB39 0.108 0.003 65 84 CB38 0.135 0.003 65 46 CB33 0.084 0.003 65 64 (832 0.12 0.003 65 82 CB31 0.168 0.003 65 114 CB30 0.097 0.003 65 67 CB40 0.076 0.003 65 84 CB42 0.083 0.003 65 93 C858 0.059 0.003 65 62.5 CB49 0.065 0.003 65 80 (846 0.065 0.003 65 69 CB47 O.Q38 0.003 65 41 Gl-2 0.056 0.003 65 50 Gl-1 0.057 0.003 65 50 C855 0.034 0.003 65 50 CB56 0.034 0.003 65 50 (854 0.057 0.003 65 50 CB53 O.Q35 0.003 65 49 (852 0.035 0.003 65 40 CBS! 0.057 0.003 65 so Pond NA NA NA NA OF NA NA NA NA XPSWMM Catch Basin (Node) & Pipe (Link) Output Summary Node Output Data Summary for 25-year Event Duration of Ma)( Water Max Water Depth Surcharge Duration of Node Name Elevation (ft} (ft] Freeboard (ft) (min] Flooding (min) CBlO 436.590 0.080 1.33 0.0 0.0 CBll 436.379 0.119 1.54 0.0 0.0 CB12 436.110 0.150 1.81 0.0 0.0 CB13 435.837 0.177 2.08 0.0 0.0 CB14 435.438 0.198 2.48 0.0 0.0 CB15 434.864 0.364 3.06 0.0 0.0 CB16 434.648 0.378 3.27 0.0 0.0 CB17 434.411 0.391 3.51 0.0 0.0 CB18 434.141 0.411 3.78 0.0 0.0 CB19 433.911 0.431 4.01 0.0 0.0 CB20 433.230 0.350 4.69 0.0 0.0 CB21 432.938 0.358 4.98 0.0 0.0 CB29 431.476 0.786 6.44 0.0 0.0 CB28 435.343 0.213 2.41 0.0 0.0 CB27 435.978 0.208 1.77 0.0 0.0 CB26 436.554 0.134 1.20 0.0 0.0 CB25 435.210 0.270 2.54 0.0 0.0 CB24 435.563 0.323 2.19 0.0 0.0 CB23 436.162 0.202 1.59 0.0 0.0 CB22 436.631 0.121 1.12 0.0 0.0 CB37 431.639 0.659 6.28 0.0 0.0 CB35 436.090 0.210 1.66 0.0 0.0 CB36 435.225 0.215 2.53 0.0 0.0 CB34 436.554 0.134 1.20 0.0 0.0 CB50 431.908 0.548 6.01 0.0 0.0 CB48 432.178 0.518 5.57 0.0 0.0 CB45 433.015 0.485 4.73 0.0 0.0 CB57 434.566 0.456 3.18 0.0 0.0 CB44 434.875 0.435 2.87 0.0 0.0 CB43 434.982 0.442 2.77 0.0 0.0 CB41 435.780 0.290 1.97 0.0 0.0 CB39 436.433 0.223 1.32 0.0 0.0 CB38 436.652 0.142 1.10 0.0 0.0 CB33 435.203 0.283 2.55 0.0 0.0 CB32 435.485 0.245 2.26 0.0 0.0 CB31 436.163 0.203 1.59 0.0 0.0 CB30 436.631 0.121 1.12 0.0 0.0 CB40 436.558 0.108 0.98 0.0 0.0 CB42 436.364 0.114 1.14 0.0 0.0 CB58 436.097 0.097 1.40 0.0 0.0 CB49 436.102 0.102 1.65 0.0 0.0 CB46 433.017 0.267 4.73 0.0 0.0 CB47 433.057 0.077 4.69 0.0 0.0 Gl-2 435.369 0.159 4.28 0.0 0.0 Gl-1 435.368 0.158 4.28 0.0 0.0 CB55 436.037 0.107 2.21 0.0 0.0 CB56 436.522 0.072 1.73 0.0 0.0 CB54 436.349 0.099 1.90 0.0 0.0 CB53 436.038 0.108 2.21 0.0 0.0 CB52 436.528 O.D78 1.72 0.0 0.0 CB51 436.349 0.099 1.90 0.0 0.0 OF 425.536 1.151 11.96 0.0 0.0 Node Output Data Summary for 100-year Event Max Water Max Water Freeboard Duration of Duration of Node Name Elevation (ft) Depth (ft) (ft) Surcharge (min) Flooding (min) (810 436.596 0.086 1.32 0.0 0.0 C811 436.389 0.129 1.53 0.0 0.0 (812 436.123 0.163 1.80 0.0 0.0 (813 435.852 0.192 2.07 0.0 0.0 CB14 435.455 0.215 2.46 0.0 0.0 CB15 434.904 0.404 3.02 0.0 0.0 (816 434.691 0.421 3.23 0.0 0.0 CB17 434.457 0.437 3.46 0.0 0.0 [818 434.190 0.460 3.73 0.0 0.0 (819 433.960 0.480 3.96 0.0 0.0 (820 433.262 0.382 4.66 0.0 0.0 (821 432.971 0.391 4.95 0.0 0.0 (829 431.570 0.880 6.35 0.0 0.0 (828 435.361 0.231 2.39 0.0 0.0 (827 435.996 0.226 1.75 0.0 0.0 (826 436.565 0.145 1.18 0.0 0.0 (825 435.234 0.294 2.52 0.0 0.0 CB24 435.583 0.343 2.17 0.0 0.0 (823 436.179 0.219 1.57 0.0 0.0 (822 436.641 0.131 1.11 0.0 0.0 CB37 431.737 0.757 6.18 0.0 0.0 CB35 436.109 0.229 1.64 0.0 0.0 (836 435.243 0.233 2.51 0.0 0.0 (834 436.565 0.145 1.19 0.0 0.0 C850 431.982 0.622 5.94 0.0 0.0 (848 432.237 0.577 5.51 0.0 0.0 (845 433.065 0.535 4.69 0.0 0.0 CBS7 434.610 0.500 3.14 0.0 0.0 CB44 434.918 0.478 2.83 0.0 0.0 (843 435.023 0.483 2.73 0.0 0.0 CB41 435.808 0.318 1.94 0.0 0.0 CB39 436.453 0.243 1.30 0.0 0.0 CB38 436.664 0.154 1.09 0.0 0.0 CB33 435.234 0.314 2.52 0.0 0.0 (832 435.509 0.269 2.24 0.0 0.0 CB31 436.180 0.220 1.57 0.0 0.0 CB30 436.641 0.131 1.11 0.0 0.0 CB40 436.567 0.117 0.97 0.0 0.0 CB42 436.373 0.123 1.13 0.0 0.0 CB58 436.105 0.105 1.40 0.0 0.0 CB49 436.110 0.110 1.64 0.0 0.0 CB46 433.066 0.316 4.68 0.0 0.0 CB47 433.081 0.101 4.67 0.0 0.0 Gl-2 435.382 0.172 4.27 0.0 0.0 Gl-1 435.382 0.172 4.27 0.0 0.0 C855 436.045 0.115 2.20 0.0 0.0 C856 436.528 0.078 1.72 0.0 0.0 CB54 436.357 0.107 1.89 0.0 0.0 CB53 436.047 0.117 2.20 0.0 0.0 CB52 436.534 0.084 1.72 0.0 0.0 CB51 436.357 0.107 1.89 0.0 0.0 Pond 429.500 5.105 8.00 0.0 0.0 OF 425.536 1.151 11.96 101.135 0.0 Link Output Data Summary for 25-year Event Max Max Upstream Downstream Design Full Max Depth Max d/D Max Flow Tailwater Headwater link Name Node Name Node Name Flow (cfs) (ft) (depth/diameter) (els) (ft) (ft) link4 (810 (811 0.94 0.119 0.177 0.028 436.379 436.590 Links CB11 (812 0.94 0.150 0.225 0.064 436.110 436.379 Link6 CB12 CB13 0.94 0.177 0.264 0.104 435.837 436.110 link7 (813 (814 0.94 0.177 0.264 0.140 435.581 435.837 Link8 (814 (815 0.94 0.198 0.296 0.176 435.112 435.438 Link9 C815 C816 0.94 0.378 0.564 0.531 434.648 434.864 LinklO (816 (817 0.94 0.391 0.584 0.564 434.411 434.648 Link11 (817 (818 0.95 0.411 0.613 0.600 434.141 434.411 Link12 C818 C819 0.94 0.431 0.644 0.637 433.911 434.141 Link13 (819 C820 0.91 0.431 0.644 0.675 433.596 433.911 Link14 (820 (821 2.73 0.358 0.358 0.715 432.938 433.230 Link15 (821 (829 2.71 0.358 0.358 0.743 432.618 432.938 Link54 C829 Pond 2.73 0.786 0.786 2.842 431.223 431.476 Link18 (828 C829 2.73 0.213 0.213 0.271 435.042 435.343 Link17 C827 C828 0.94 0.208 0.311 0.193 435.431 435.978 link16 C826 C827 0.94 0.134 0.201 0.080 435.998 436.554 link22 C825 C815 0.95 0.270 0.403 0.319 434.864 435.210 link21 C824 C825 1.10 0.240 0.358 0.263 435.210 435.563 Link20 CB23 CB24 0.94 0.202 0.301 0.181 435.605 436.162 Linkl9 CB22 CB23 0.94 0.202 0.301 0.067 436.162 436.631 Link30 CB37 C829 2.73 0.786 0.786 1.788 431.476 431.639 Link28 CB35 C836 0.94 0.210 0.314 0.196 435.543 436.090 Link29 CB36 CB37 2.73 0.215 0.215 0.276 434.924 435.225 Link27 C834 C835 0.94 0.210 0.314 0.082 436.090 436.554 Link39 C850 CB37 2.73 0.659 0.659 1.472 431.639 431.908 Link38 C848 C850 2.73 0.548 0.548 1.411 431.908 432.178 Link37 C845 CB48 2.73 0.485 0.485 1.292 432.470 433.015 Link36 C857 C845 2.73 0.456 0.456 1.161 434.264 434.566 Link35 CB44 (857 2.75 0.456 0.456 1.066 434.566 434.875 Link34 CB43 (844 2.11 0.442 0.442 0.879 434.875 434.982 Link33 CB41 (843 0.94 0.291 0.434 0.359 435.398 435.780 Link32 CB39 CB41 0.94 0.223 0.333 0.220 435.875 436.433 Link31 CB38 CB39 0.94 0.223 0.333 0.093 436.433 436.652 Link26 CB33 CB43 0.94 0.442 0.659 0.324 434.981 435.203 Link25 CB32 CB33 0.94 0.283 0.422 0.266 435.203 435.485 Link24 CB31 CB32 0.94 0.203 0.303 0.183 435.606 436.163 Link23 C830 CB31 0.94 0.203 0.303 0.067 436.163 436.631 Link44 C840 CB39 0.94 0.183 0.273 0.053 436.433 436.558 Link43 CB42 CB41 0.94 0.114 0.170 0.057 436.158 436.364 Link42 CB58 (857 0.94 0.097 0.145 0.041 435.890 436.097 Link40 CB49 (848 0.94 0.102 0.152 0.045 435.895 436.102 Link41 C846 CB45 0.94 0.415 0.620 0.071 433.015 433.017 Link45 CB47 CB46 0.95 0.267 0.398 0.026 433.017 433.057 Link46 Gl-2 (843 1.03 0.192 0.286 0.127 434.981 435.369 Link47 Gl-1 C844 1.03 0.158 0.236 0.126 434.948 435.368 Link51 C855 Gl-1 0.47 0.107 0.213 0.047 435.816 436.037 LinkSO C856 C855 0.52 0.107 0.213 0.024 436.037 436.522 link52 C854 Gl-1 0.47 0.099 0.198 0.039 435.937 436.349 Link49 (853 Gl-2 0.47 0.108 0.216 0.048 435.817 436.038 Link48 C852 C853 0.47 0.078 0.156 0.024 436.105 436.528 Link53 C851 Gl-2 0.47 0.099 0.198 0.039 435.937 436.349 Link56 Pond OF 0.00 -9.00E+99 0.000 0.000 0.000 0.000 Link56 Pond OF 8.95 5.103 4.434 16.008 425.536 429.135 link56 Pond OF 41.69 0.253 0.119 0.068 429.322 429.478 Link56 Pond OF 35.63 -9.00E+99 0.000 0.000 0.000 0.000 Link Output Data Summary for 100-year Event Maxd/D Max Max Upstream Downstream Design Full Max (depth/ Max Flow Tailwater Headwater Link Name Node Name Node Name Flow (cfs) Depth (ft) diameter) (els) (ft) (ft) Link4 CB10 CB11 0.94 0.129 0.192 0.033 436.389 436.596 Links CB11 CB12 0.94 0.163 0.243 0.076 436.123 436.389 Link6 CB12 CB13 0.94 0.192 0.286 0.122 435.852 436.123 Link7 CB13 CB14 0.94 0.192 0.286 0.165 435.596 435.852 Link8 CB14 CB15 0.94 0.215 0.321 0.206 435.128 435.455 Link9 CB15 CB16 0.94 0.421 0.628 0.623 434.691 434.904 LinklO CB16 CB17 0.94 0.437 0.652 0.662 434.457 434.691 Linkll CB17 CB18 0.95 0.460 0.687 0.704 434.190 434.457 Link12 CB18 CB19 0.94 0.480 0.717 0.749 433.960 434.190 Link13 CB19 CB20 0.91 0.480 0.717 0.792 433.630 433.960 Link14 CB20 CB21 2.73 0.391 0.391 0.840 432.971 433.262 Link15 CB21 CB29 2.71 0.391 0.391 0.873 432.650 432.971 Link54 CB29 Pond 2.73 0.880 0.880 3.339 431.281 431.570 Link18 CB28 CB29 2.73 0.231 0.231 0.318 435.060 435.361 Link17 CB27 CB28 0.94 0.226 0.338 0.226 435.449 435.996 Link16 CB26 CB27 0.94 0.145 0.217 0.094 436.009 436.565 Link22 CB25 CB15 0.95 0.304 0.454 0.375 434.904 435.234 Link21 CB24 CB25 1.10 0.264 0.394 0.309 435.234 435.583 Link20 CB23 CB24 0.94 0.219 0.327 0.213 435.622 436.179 Link19 CB22 CB23 0.94 0.219 0.327 0.079 436.179 436.641 Link30 CB37 CB29 2.73 0.880 0.880 2.101 431.570 431.737 Link28 CB35 CB36 0.94 0.229 0.341 0.231 435.561 436.109 Link29 CB36 CB37 2.73 0.233 0.233 0.324 434.942 435.243 Link27 CB34 CB35 0.94 0.229 0.341 0.096 436.109 436.565 Link39 CB50 CB37 2.73 0.757 0.757 1.729 431.737 431.982 Link38 CB48 CB50 2.73 0.622 0.622 1.658 431.982 432.237 Link37 CB45 CB48 2.73 0.535 0.535 1.518 432.512 433.065 Link36 CB57 CB45 2.73 0.500 0.500 1.364 434.304 434.610 Link35 CB44 CB57 2.75 0.500 0.500 1.252 434.610 434.918 Link34 CB43 CB44 2.11 0.483 0.483 1.033 434.918 435.023 Link33 CB41 CB43 0.94 0.318 0.475 0.422 435.422 435.808 Link32 CB39 CB41 0.94 0.243 0.362 0.258 435.894 436.453 Link31 CB38 CB39 0.94 0.243 0.362 0.109 436.453 436.664 Link26 CB33 CB43 0.94 0.483 0.722 0.381 435.023 435.234 Link25 CB32 CB33 0.94 0.314 0.469 0.313 435.234 435.509 Link24 CB31 CB32 0.94 0.220 0.329 0.215 435.623 436.180 Link23 CB30 CB31 0.94 0.220 0.329 0.079 436.180 436.641 Link44 CB40 CB39 0.94 0.203 0.303 0.062 436.453 436.567 Link43 CB42 CB41 0.94 0.123 0.184 0.067 436.167 436.373 Link42 CB58 CB57 0.94 0.105 0.156 0.048 435.898 436.105 Link40 CB49 CB48 0.94 0.110 0.164 0.053 435.903 436.110 Link41 CB46 CB45 0.94 0.465 0.694 0,084 433.060 433.062 Link45 CB47 CB46 0.95 0.316 0.472 0.031 433.066 433.081 Link46 Gl-2 CB43 1.03 0.233 0.348 0.149 435.023 435.382 Link47 Gl-1 (844 1.03 0.172 0.256 0.148 434.961 435.382 Link51 CB55 Gl-1 0.47 0.115 0.231 0.055 435.825 436,045 Link50 CB56 CB55 0.52 0.115 0.231 0.028 436.045 436.528 Link52 CB54 Gl-1 0.47 0.107 0.214 0.046 435.945 436.357 Link49 CB53 Gl-2 0.47 0.117 0.234 0.057 435.827 436.047 Link48 CB52 CB53 0.47 0.084 0.168 0.028 436,112 436.534 Link53 CBS! Gl-2 0.47 0.107 0.214 0.046 435.945 436.357 Link55 Pond OF 0.00 -9.00E+99 0 0 0 0 Link55 Pond OF 8.95 5.103 4.434 16.008 425.536 429.135 Link55 Pond OF 41.69 0.253 0.119 0.068 429.322 429.478 LinkSS Pond OF 35.63 -9.00E+99 a a 0 0 This page intentionally left blank. Appendix F CSWPPP Stormwater Pollution Prevention Plan owner Puget Sound Energy 355 110th Avenue NE Bellevue, WA 98009 For Talbot Hill Substation Prepared for City of Renton 1055 South Grady Way Renton, WA 98057 Project Site Location Puget Drive SE in Renton, WA. Erosion and Sediment Control Lead: Phone: SWPPP Prepared By HOR Engineering 500 108th Avenue NE Suite 1200 Bellevue, WA 98008-5549 SWPPP Preparation Date 10/4/2016 Approximate Project Construction Start Date April-May 2017 Operator TBD 1-)~ Contact Information Title Nilmels) Pfione Nurnber . ,.'' Certified Erosion and Sediment Control Lead TBD TBD Emergency Owner Contact TBD TBD Emergency Oil Spill Response TBD TBD Owner / Operator Contact TBD TBD Table of Contents Stormwater Pollution Prevention plan ............... 1 Appendix A: Site Plan ..................................... 5 Recommended Construction Sequence 1. Pre-construction meeting. 2. Post notice of construction activity sign with name and phone number of CESCL. 3. Flag or fence clearing limits. 4. Install catch basin protection where required. 5. Install perimeter protection (silt fence). 6. Construct surface water controls simultaneously with clearing and grading for project development. 7. Maintain erosion control measures in accordance with City of Renton Standards and Manufacturers recommendations. 8. Relocate surface water controls and erosion control measures or install new measurers so that as site conditions change the erosion and sediment control is always in accordance with the City of Renton Erosion and Sediment Control Standards. 9. Cover all areas that will be unworked for more than seven days during the dry season or two days during the wet season with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. 10. Stabilize all areas that reach final grade within seven days. 11. Seed or sod any areas to remain unworked for more than 30 days. 12. Upon completion of the project, all disturbed areas must be stabilized and best management practices removed if appropriate. Design Standards The Washington State Department of Ecology (DOE) 2012 Stormwater Management Manual for Western Washington (SWMMWW) King County 1998 Erosion and Sediment Control Standards City of Renton Amendment to the 2009 King County Surface Water Design Manual 500 1081h Ave NE. Suite 1200, Bellevue, WA 98004-5549 (425) 450-6200 hdrlnc.com Introduction This Stormwater Pollution Prevention Plan (SW PPP) has been prepared as part of the National Pollutant Discharge Elimination System (NP DES) stormwater permit requirements for the proposed work associated with the Talbot Hill Substation project. This SWPPP will be revised as necessary to reflect the Contractor's means and methods and all revisions will be in compliance with the best management practices (BMPs) presented in this SWPPP. The purpose of this SWPPP is to describe the proposed construction activities and all temporary and permanent erosion and sediment control (TESC) measures, pollution prevention measures, inspection/monitoring activities, and recordkeeping that will be implemented during the proposed utility work. The objectives of the SW PPP are to: 1. Implement BMPs to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. Prevent violations of surface water quality, ground water quality, or sediment management standards. 3. Prevent adverse water quality impacts during the construction phase, including impacts on beneficial uses of the receiving water by controlling peak flow rates and volumes of stormwater runoff at the Permittee's outfalls and downstream of the outfalls. Site Description Existing Conditions The Talbot Substation covers approximately 7.75 acres between Beacon Way South, South Puget Drive, and Grant Ave South in Renton. The site is located near the top of a ridge and is primarily accessed from South Puget Drive, which ties into a gravel driveway leading to the site. The topography inside the substation slopes slightly away from the center to promote drainage away from electrical equipment. The existing grade outside the substation fence generally slopes away from the substation except on the eastern and northwestern sides where there is elevated terrain. In general stormwater runoff flows outwards from the middle of the substation. Areas of localized ponding occur on the eastern and northwestern sides of the site where stormwater is constrained by elevated terrain outside the substation fence. Existing drainage pipes on the northeast and southeast sides of the substation are tied to catch basins within the fence line whose rims are slightly raised above the yard rock, preventing them from capturing and conveying flow outside of the substation. The perimeter path on the northeastern side of the substation is slightly higher than the existing grade within the fence line, preventing flow from draining off the site along this edge. An elevated field along the eastern edge of the site prevents drainage away from the substation on this side. Along the southern edge of the substation, runoff is able to flow south across the southern perimeter path and into a depression located between the substation and access road. This route presents the least constrained flow path for stormwater to exit the project area. The depression is then drained by a culvert beneath the access road to a second depression which drains eastwards, paralleling a gravel access road towards Grant Avenue South. Seven borings were performed as part of a geotechnical study at the project area. Five of these borings were performed inside the substation, and these discovered several feet of fill soils overlying seven to twenty three feet of glacial till. In the area of the proposed stormwater detention pond two borings were 2 1-)~ performed which discovered several feet of loose sand and organic topsoil overlying glacial till. Advance outwash deposits were found below the till soils in all boring samples. No groundwater was encountered at the project site (GeoEngineers, 2016). Proposed Construction Activities The scope of this SWPPP for the Talbot Hill Substation is limited to: • the installation of all new substation components within the fence line of the existing substation, • the installation of the new substation perimeter fence, • the paving of the existing access road, • and the installation of the proposed stormwater detention pond, its control structure, and inlet and outlet located at the southeast corner of the substation, All work except for the pond construction and roadway repaving is being completed within the proposed substation fenceline. Below is a site detail summary, giving the approximate area of the utility improvement corridor and impervious areas affected by the utility work. Total Site Area (ac): 5.89 Approximate Percent Impervious Before Construction (%): 56 Approximate Percent Impervious After Construction (%): 65 Disturbed Area During Construction (ac): 4.65 Approximate Excavation Volume (CY): 12,400 ESC Measures 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. The construction of the proposed stormwater detention pond and paving of the existing access road will be the only ground disturbing activity occurring outside of the substation fence. Natural vegetation and topsoil at the project area shall be retained to the maximum extent feasible. High visibility fence and silt fence BMPs will be used around the perimeter of the project area to ensure disturbance is kept to a minimum outside the work area. Installation Schedules: High visibility fence and silt fence will be installed before site disturbing activities begin. Inspection and Maintenance plan: Inspect the fence once every calendar week, and within 24 hours of any stormwater or non-stormwater discharge from the project site. Repair any damage to the high visibility fence immediately. Cover Measures As the project is located west of the Cascade Mountain Crest, no soils shall remain exposed and unworked for more than seven days during the dry season (May 1 to September 30) and two days during the wet season (October 1 to April 30). Between these times, exposed soils stored aboveground shall be protected with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. Regardless of time, all soils shall be 500 108th Ave NE, Suite 1200, Bellevue. WA 98004-5549 (425) 450-6200 hdrinc.com stabilized at the end of the shift before a holiday or weekend, and if needed, based on weather forecasts. Any areas expected to remain unworked for greater than 30 days must be seeded or sodded (King County, 1998). During the wet season, soil stockpiles with slopes greater than or equal to 3H:1 V, or with over ten feet of vertical relief must be covered if they will remain unworked for over 12 hours. During the wet season sufficient cover materials to stabilize all disturbed areas must be stockpiled on site, and the Wet Season Provisions of Section D.5.s of the King County Erosion and Sediment Control Standards must be followed (King County, 1998). Permanent stabilization will be achieved by placement of yard rock within the substation, and seeding at the proposed stormwater detention pond. Installation Schedules: BMPs will be installed as necessary on a temporary basis during construction. Inspection and Maintenance plan: Inspect once every calendar week, and within 24 hours of any stormwater or non-stormwater discharge from the project site. Repair or replace damaged BMPs immediately. Perimeter Protection Vegetation and slope characteristics vary within the project area. The eastern edge of the project area is elevated and there is no risk contaminated stormwater will exit the project site in that area. The proposed stormwater detention pond and its outlet structure will be installed along the southern edge of the project area. Silt fence will be installed in this area to ensure no contaminated stormwater exits the project area. Silt fencing will extend along the existing access road to its intersection with Puget Drive Southeast to prevent sediment generated from the proposed paving activities from exiting the project site. Concrete will be poured on site for proposed electrical equipment foundations within the substation. All concrete at the project area will be handled such that no cementitious material will enter stormwater runoff. Handling procedures are detailed on the TESC plans. Installation Schedules: Silt fence will be installed prior to ground disturbing activities. Concrete pouring and handling procedures will be adhered to at all times. Inspection and Maintenance plan: Inspect once every calendar week, and within 24 hours of any stormwater or non-stormwater discharge from the project site. Repair or replace damaged BMPs immediately. Traffic Area Stabilization The project area will be accessed from the existing access road located on the southern edge of the substation. This access road is a stabilized surface and does not require additional stabilization. Proposed stormwater detention pond construction and access road paving will occur from the existing access road. Sediment Retention The proposed stormwater detention pond will be retrofitted as a temporary sediment storage facility for the duration of the project. All open grate catch basins and inlets located at the project area will be protected with storm drain inlet protection in order to prevent sediment contamination from entering the conveyance system. 3 1-)~ Installation Schedules: The proposed stormwater detention pond will be retrofitted as a sediment storage facility once pond construction is complete. The sediment pond must have adequate surface area as defined in Section D.4.5.2 of the King County Erosion and Sediment Control Standards (King County, 1998). Required Pond Surface Area at top of Riser -SA = 2 x Q,/0.00096 Proposed 2-year Peak Flow -0 2 = 0.079 Cubic Feet per Second Required SA = 165 Square Feet Provided SA= -19,000 Square Feet Install storm drain inlet protection as soon as catch basin and inlet facilities are constructed. Conveyance pipes will be connected after inlet protection has been fitted to structures. Inspection and Maintenance plan: Inspect all BMPs once every calendar week, and within 24 hours of any stormwater or non-stormwater discharge from the project site. Sediment shall be removed from the pond when it reaches a depth of one foot. Any damage to embankments or slopes shall be repaired immediately upon observation. Any sediment accumulated on or around storm drain inlet protection filter fabric shall be removed and disposed of offsite. Accumulated sediment will not be washed with water. Sediment will be removed from within the catch basin once it has filled 1/3 of the available space within the inlet protection insert (King County, 1998). Surface Water Collection Outlet protection will be installed at the outlet of the proposed stormwater detention pond before stormwater is routed through the facility. Installation Schedules: Will be installed once the proposed stormwater detention pond is completed, prior to discharge through the facility and retrofit as a temporary sediment pond. Inspection and Maintenance plan: Inspect once every calendar week, and within 24 hours of any stormwater or non-stormwater discharge from the project site. If there is scour observed at the outlet, the eroded area shall be protected with more conservative measures. Dewatering Control Dewatering is not anticipated at the project site, as groundwater was not encountered during field activities performed by GeoEngineers (GeoEngineers, 2016). Dust Control Wind transport of soils is not anticipated at the project site. Exposed soils will be stabilized and will not remain exposed for long periods. Flow Control The project area triggers Core Requirement #3: Flow Control. The proposed stormwater detention pond will be retrofitted to serve as a sediment pond during construction. During this period, the hydraulic control structure and pond will continue to function as flow control facility's and restrict flow rates exiting the site to acceptable limits. 500 108th Ave NE, Suite 1200, Bellevue, WA 98004-5549 (425) 450-6200 hdrinc.com Maintain BMPs All temporary and permanent erosion and sediment control BMPs will be maintained and repaired as needed to assure continued performance of their intended function. Maintenance and repair will be conducted as noted above. Visual monitoring of the BMPs will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the project site. If the project site becomes inactive and is temporarily stabilized, the inspection frequency will be reduced to once every month (Washington State Department of Ecology, 2012). All temporary erosion and sediment control BMPs will be removed within 30 days after the final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment will be removed and disposed of in an approved offsite location. Disturbed soil resulting from removal of BMPs or vegetation will be permanently stabilized. Manage the Project Sediment and erosion will be controlled locally around excavations and all TESC measures will be maintained in a functional condition at all times. The SWPPP shall be modified whenever there is a change in the 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 shall be modified if, during inspections or investigations, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven days following the inspection. The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. Site inspections will be conducted in accordance with Special Condition S4 of the CSWGP. Construction Schedule Construction at the site will be phased and the majority of the project work will begin between April and May of 2017. A small amount of additional site work will occur during the same period in 2018. The TESC practices prescribed in this document will be employed during both periods. Recordkeeping and Reporting A copy of the SWPPP shall be retained on site at all times. Records will be retained during the life of the project and for a minimum of three years following project completion. Several other documents must also be retained at the site and easily accessible. They are as follows: • General Permit • Notice of Authorization Letter Copies of the SWPPP shall be provided to Ecology within 14 days of receiving a written request, and furnished to the public provided the request is in writing and per permit condition S5.G of the Construction Stormwater General Permit (Washington State Department of Ecology, 2010). Following the failure to meet any of the terms and conditions of the permit and causing a threat to humans or the environment: 4 1-)~ • Ecology must be notified immediately of the failure • Action must be taken to deal with the issue immediately • A report must be submitted to Ecology within five days of the failure to meet terms or conditions • An application form covered by the General Permit must be turned in to Ecology and any applicable local jurisdiction The SWPPP will be modified if it is ineffective in preventing stormwater borne pollutants from leaving the project site, or if there have been any changes which could have a significant impact on real or potential discharge of pollutants to state-owned water bodies. The SWPPP must be modified within seven days after determining that additional or modified BMPs are needed to correct problems. Accompanying these changes, an updated BMP implementation schedule will be created. Inspection and Monitoring All BMPs will be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections must occur at least once a week, and within 24 hours of any discharge from the project site. Stormwater will be inspected for suspended sediment, turbidity, discoloration, and oily sheen. If there is a visible change in discharge during the day it is recommended that a second sample is taken. The procedure for discharge sampling is as follows: • Take one sample from just upstream of the discharge point to establish baseline turbidity levels and temperature. • Take a second sample of the project water at the discharge point. • Take a third sample several feet downstream of the discharge point. The effectiveness of all installed BMPs will determine if additional BMPs are necessary to better the quality of stormwater discharge. References United States Department of Agriculture. (2013, December 6). Web Soil Survey. Retrieved August 5, 2014, from Natural Resources Conservation Service: http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx Environmental Protection Agency. (2008). Watershed Assessment Tracking and Environmental Results. Retrieved January 22, 2015, from United States Environmental Protection Agency: http://ofmpub.epa.gov/tmdl_waters1 0/attains_watershed.control?p_huc= 17110019&p_cycle=&p_re po rt_ type= T King County. (2009). Surface Water Design Manual. Seattle: King County . Washington State Department of Ecology. (2010). Construction Stormwater General Permit. Lacey: Wasington State Department of Ecology. Washington State Department of Ecology. (2012). Stormwater Management Manual for Western Washington. Lacey: Washington State Department of Ecology. 500 108th Ave NE, Suite 1200, Bellevue, WA 98004-5549 I 425) 450-6200 hdrinc.com 5 Appendix A TESC Plans 500 108th Ave NE, Suite 1200, Bellevue, WA 98004-5549 (425) 450-6200 1-)~ hdrinc.com This page intentionally left blank 6 500 108th Ave NE, Suite 1200, Bellevue, WA 98004-5549 (425) 450-6200 1-)~ hdrinc.com . . ~ . w . < 0 . RECOMMENDED CONSTRUCTION SEQUENCE RECOMMENDED CONSTRUCTION SEQUENCE (CONTINUED) '. ,. 4. s. 6. 7. PRE-CONSTRUCTION r.tEET!NG. POST NOIJCf:. OF CO'iSTHUCT[DN ACTJVITY SIGN w1rH NAME AND PHOM£ NUMBER OF r.F SCI • ,. ,. RELOCATE SURFACE WATER CONTROLS ANO EROSION CONTR:L MEASURES OR INSTAI I NFW r.tEASLIRES SO ThAT AS s:TE CONDITIONS CIIANG[ TH[ UlOSfON /,ND SEO[MENT CONTRO_ JS ALWAYS IN ACCOROANU WITH Th£ Cl~Y OF RENTO~ HIOSION ANO SEDIMENT CONTROL SlANlJAHDS, --=,-Z-= MATCH LINE -SEET SHEET 2 covrn Al L AREAS THAT Wll L. 6[ UN'IIORKEO FOR MOR[ THAN SEVFN DAYS OUR ING THE ORY SEASON Oil TWO DAYS DURING lHE WET SEASON WlTH STRAW, WOOD F!BER MULC~. COMPOST, PLASTIC SHEETING OR EOUl\lAI FNT, FLAG OR FENCE CLEARING LIM!TS, INSTALL CATCH BASIN PROTECTION (F REQUIRED. ,o. STABtL12E ALL AREAS THAT REACH FINAL GRADE wn11:N SEVEN DAYS. / / / \ . j~;~·~~=;~-::~c-.\o n~l, 1\\ ·/J;...1 1XB~~~-...-~r.-~ · 11 -/ -·t. /ii, f' 1 I f.@;;:::.~'2.2,: C'-.":z_~ . ( ' , ·11· 1'1" (j!(~"'-~~"0! ~ I '' < / . _. < 'l 1:i1~Jlf'l1 ~~~ ~ . ) ,£/ Q tiMnNG~ \ b~~~c~Ig~r~l6J"ILITY j~U'.· 11i~;1l11II \\=';~~~~~- ' n , _l_ , _ _ ~~~s~~JJ~N/ENg~. It· II. 1\,. '\' }~~~~~ ----··------·-·· -------·-_ _ _ • DETAIL 3 1· w ," · oi?~'"" ~~=s==-,=--=~ ---I I l~STA~L PERIMETER PROTECTION IS1LT FENCE, El'WSI-! BARRIER, ETC.), CONSTRUCT S~'RFACE WATER CONTROLS I !NTERCFPTOR DIKE'S, PIPE SLnPF DRAINS, ETC.) SJMULTANEOUSLY WITH CLEARING AND GRAO)t\G FOR PROJECT DEVELOPMENT. 11. SEED OR SOD ANY AREAS TO REMAIN UNWCRKEO FOR MC1PE THA'J 30 DAYS. 12-UP:N CO~PLE-:-!QN OF Tl-lE PROJECL ALL DISTURl!E.ll AREAS MUST llE STABILIZED ANO BEST MA,\AGEMC:NI PRACTJCC.S REMOVED IF APPROPRIATE. hMJNTAIN EROSION CONTROL MEIi.SURES IN ACCORDANCE W[TII CITY OR RENTON ST ANDAROS A ~D MA~UF ACTURER' S REC0!,11,!ENOA TI DNS. // /' ____ :.:::.T ' \ . :]~TI•···;;:-·· -~:.-·::·::···,~f+''_'•,ifjf." '.' ''"!"±{):'<··.:·;-··~······:~ frl*+'· '><-'·• ·,:,··'"'N:,,' +_.,,., .• ,,, .. L LJ L, L·, L', LJ L, I_, L, I L, '-' L, L::1 LJ L, L·, I..:, L, L·, ll Ii ., . 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FENCE OUTSIDE OF I~ :: ·. II II I I II 11 11 II I : : .all. 1; ,i I a 8 tif a • •1 a \. .. • • ' II ~/ ' ~····F I j~"/i<<· SUBSTATION FENCE, ( /~ = SEE SHEET 3, DETAIL 3 '-..- li.:~ r\ 1' ,, 1-:---<,, I \ ,;. '1·--1 ' ~~~~r "' / I I I, I I ,'\ I : \ \ SILT FENCE/ CONSTRUCTION LIM!TS. SFF SHFFT 3, DETAIL 4 KEY DIVIDER INTO SLOPE TO PREVENT FLOW AROLND SIDES """;--SILT FENCE OH 1 EQUIVALENT DIVIDER. I \ SHOULD BE PLACED SUCH 1THAT POND VOLUME IS jEFFECT IVEL Y SPLIT 50/50 I ,, ' I I I 'TEMPORARY SEDIMENT PONO RISER. SEE SHEET 3, DETAIL 2 I , , l~'\-·' ,.-' \ ' .. ·\-\ RIP RAP SHALL BE . -6 TO 8 11 ANGULAR ),ROCK, 18 11 DEEP / AND SHALL BE 10 1 L x lO'W CENTERED ON TRASH RACK . ' I I I J I \ TOPO LEGEND ~ATCH LIN~'.~~~~~ !:~~ ;-, •----------------0 ~-----------------.a J D~U_CJ I ,--~ '.' . ',: ,---' I D : • ' . "I : I LEGEND: I I 1, 1 I j 11 I II : I I; I I. I I " { \ ---·-------- 9-J:t -0-pp = -; a "• " + ~ 1~~~ Q 0 " ~ D D "" t.<~LN~ C>', L•~c (x,Sf.N~ O.-E"Ot1C"1l PUW!'R liNE FXISTt<G UNOCRcRCU~D TFcr~st..sr ""' NG UN.OE~~,w~o PCW!'S E(ISfK~ ,1s:,p UHC !CXIST~G CYCL.Ct,E; fl:H~C UN£ d1Sl NC >poolHTY L."l ?[}'l,(R POcf: ~/ LL.Ml~;,;,: POWSR POL[ EX15lSG 51G' rns~NG ~u,-•N:HCS EX1s1,~ SWECT ur;..- rns,,c CATGH &"5 ... [L[C"RICl.t. ao, BENC~va>K E:<lS""G T[((PHOH> MANHOl.i U•'i'1~G SlOR~ CRMJ MASHrlr,F: ~,OS'ISC flRr li"~R•Nf i:X-S~HC D[C OWCUS TR[E(~'A J RE8AR/c,a Mt,R~(D ·,,oo.£ ,,,,,._,· Exo'\n~c SJ~,A~,' M(lNJ,..,,HT F<STIN:; cc-scs~n: f:'<S~'1:; GRA,D_ ;;'~I :.LLYM![.l< ===='-' I '• d ' I,, ' II I I. I ' I' I -- 1"'·"1 SPOT EL"'""' I ' , __ , " : ' ----' iVE I ======-~--1 -4-44-PROPOSED CONTOURS I a-----=--~=~~---~..a •=---=~----~==----=a : ---444 --· EXISTING CDNT:JURS L____ _ __________ ___Ji"";:I . --I --it.--PR;JPERTY LINE 7 ~ -----1 1 ____ ~ Cl @ c=:J .. Ill CONSTRUCTION STATION FENCE LIMITS CONCRETE HANDLING SLOPE AND FLOW DIRECTION FOUND A 11 ONS I REF O~L Y l TYPE I CATCH BASIN lSEE DRA[~AGE PLAN) ·ypE II CATCH BASIN ISEE DRAINAGE PLANI DITCH LINE D~!VEWAY CATCH BASIN INSERT CLEARING DR CO~STRLJCTlON L IM!TS/HIGH VISI31L[TY FENCE SILT FENCE A lPRP.P CONCRETE JR,JCK CHUTES. PUMPS, ANO JNTERNALS SHALL BE WASHED OUl ONLY INTO A1' ECO-PAN. 2. UNUSEC· CONCRETE RFIAAlNING IN THE TRUCK AND PUMP SHALL EIE RETURNE_C. TO THE ORIGINATING BATCH PLANT FOR HECYCLING. J. HAND TOOLS INCLUDING. Bu: NOT LIMITED TO, SCREE:.us. SHUVELS. HAKES. FLOATS, ANO TROWELS SHALL BE WASHt.l) OFF ONLY INTO Al.. ECO-PAN. ~. CO~TAlNlJ CONCRETE Sr!ALL BE DISPOSED OF IN A MANN[R THAT DOES NOT VI DLA TE GROUND'NA Tl'R OR SURF ACE WATER DUAL! TY ST ANOARDS. DR THE CONDITIONS OF THE NPDES PERMIT IF APPLICABLE. s. CO~TAINE~S SHALL BE CHECKED FOR flDLES IN THE LINER JAILY DURING CCNCRETE POURS AND REPAIRED Tf!E SAl,,ff DAY. SO 0 30 60 ''° ~~ -I GRAPH[C SCALE 1" ~ 30" REFERENCE DRAWINGS D-18730 SITE LAYOUT ANC GENERAL NOTES D-18734 GRA/"llNG AND FFNC:JNG ~LAI.. D-16736 DRAINAGE PLAN D-18737 FOUI..DATIDN PLAN D-18738 STR!.2CTJRAL PLAN '@CALL BEFORE : " YOU DIG · Cal I: TOLL FREE , 1-800-424-5555 AEVIS!OH DESCRIFIIO~: IW!J NU'-!BER:111022315 TEMPORARY EROSION/SEDIMENT CONTROL PLAN-230KV SWITCHYARD TALBOT HILL SUBSTATION PERMIT SUBMITTAL DA TE ( 1,1/_Q/Y ) •~ """" ICAO I .._:. Ne.-!~ =±(I 1111 [{., ENGINEER C. /?vss;e...l/ll -_'0_?°1J'j REVIEWED SCALE:]"= 30'-0" APPROVED J l,ji:IJ_f /I I /7 I/ft!_ ICADD NO: $$DGN1$ SUBSTATION ENGINEERING DEPARTMENT CLASS: SITE ORAW[NG NO AEV NO D-18732 0 _SHEET: ~ rF~, ICOD£: TAL 8 0 " iii ~ 0 --c';j I ~ / ~ k Ifi I~ .-(•-. " m~x, ,,, . w w m \ ·:,:; .SILT,FE~CE __ : .... --< W(ST ·,oF fjER£, ,' SEE SHEE:1 3 ,, - OE'.TA['L 4· .. I I / ( RECOMMENDED CONSTRUCTION SEQUENCE srE SHE~-, ~ N ----7 \ ~------ ! -I -- ~ I ' L USE HIGH VISIBIL !TY FENCE OUTSIDE OF SUBSTATION !ENCE. SEE SHEET 3, DETAIL 3 ~~=;~~=:~~~f~~;2~~-?.a- -""='·~·- CONCRETE HANDLING SEE SHEET 1 " " " ·/·/·/. . . / /./ .. /// '/'/'/ '/'/'/ / ·x~/ "''-->::::'--. . /' ·x· ."--. -"',l,L' · .. // "-.,< ·-.J.-~· / ··. ·:---._,; -....... ' -->~ <~:~~, ~\:\\\ ,' \~\ \·•'\ . .'.\\ \ \\~· I_.../--·-... -~~r '.J' ! I I I · J/' '/'· / /. ·/ Ir ( l -Q~C: ~"GEfJ[' \>--0 v,, / / = --, " °" " + "' ~C~h fJ, 0 © 0 LJ [~ "' E•~TIN:; G>S US[ EXSl1N~ O,S:~>tEAO PO\\,;S CISE Fx•SilNG US)ffl('.a(>,)NU 1Cc<.l'SOS[ £,:srn,~ IJN'.'E~C.SC<.,ND >Q'McP. lXISll~~ ~'Al[R UN£ £>:IST·NG CYCLCS~ n.,.c, UN£ E<ISIINC PRCH:"r, UNO PO""' PCL.E W/ LC~ NA.Rf C<'S"11'C SlC_., rus~~G G,UY •N:,ICR EXIS~r<G s-ar,-ll01T E;,S-INU (AfC>< ~AON w:cT~:CA, M, CjfNC>WA~S OISTM<~ IEcC~HONE ,.,r<SOCS rn,,,,.c s·oiar. tRAJN Ymems f.<IS-l'IG FIS[ HrGRSIJl rnsr,><; owo,,cus rnrr,r.s.: RCO~R/:AP YAR<EC ·ss.JC.J( ,,,.~- '"~TIN(, suorACc ~·:),,,U~[NT '"STING ~csu~(W " CASE C<C"~ CCHN':T[ $?OJ ,,r,nos r ----__, "---- ;cO ):ti::=:01,-,-, 7l!J!l;}Jtrw,. · -=+-/ . ----' i~-·~~ _,__..;-~;;_...,..·-- LEGEND: 1438.251 Sf'OT ELEVATION -444 · -KK5l CONTOURS OITCK LINE GRAVEL ACCESS RCAO ASPKAL T CLEARING LIMITS/HJGII VISIB[L!TY FF:NCE SILT FENCE REFERENCE DRAWINGS D-!BDO SITE LHDUT AND GENERAL NOTES C-18734 GRADING AND FENCING PLAN C-18736 DRAINAGE PLAN D-18737 0-1 B738 FOicNDA Tl ON PL AN STRUCTURAL PLAN 6 /-----~ Di St- ..--.----_.,,----',?'::,Gf-·@· CALL BEFORE "-YOU DIG !fl Cal I: TOLL FREE . 1-800-424-5555 ]C 0 "'-"" ..,/ ''° I 30 eo ! -=---i GRAPHIC SCALE 1' ~ 30' ~=-=--=---r====,,----,----------,-.,-----:-:-c:----::--+' REVISION DESCRIPTION: WD NU .. BER: 1 \ 1022315 TEMPORARY EROS I ON/SEO I MENT '""IT scsrnm CONTROL PLAN-ACCESS ROAD TALBOT HILL SUBSTATION DATE (M/0/Yl +~ SUBSTATION DR~'il!NG ND rE~NO c,o --- , ' ENGINEERING D-18732 ENERGY DEPARTMENT ENG [NEER c.x.,.,~/1 ;, II~ I/;_ SHEET: ' ~ ' REV[EWED ' ' SCALE:1" = 30' CLASS: SJ TE ~ APPROVED J, f.lE•IR_v /I _!__ /.:;" I /(;, CAOD MO: $$0GN~$ ' " w " .: w < ~ STANDl<RD STRENGT~ rlL TER FABRIC GRATE 1wnfn~ ......... £.,, MAl_NTEf_iANCE_ STt,,_NDARDS P<ll'TIHYL.(NE CAP Pl«JVIIJI': .o.:JEOUKE Sil'.APPING =1 11 Ill= =II II~ =1· 111=-=I I Ill= =1,1 ~,, .. , .. 1 !Ii= 1=11 0111= .1-=!1 'rill/\ lll= ,Jin~ FILTER FABRIC PROTECTION NOTE.: DNL Y TO BE USU WHERE PONDING OF WI\TER ABOVE THE CATCH OAS!N WILL NOT CAUSE TRAFF !C PROE!LEt..15 AND w·~ERE OVf.RFLOW WlLL NOT RESULT IN ERClS tnN OF SLOPES. -CATCH BASIN L GRATE CTTJJ)TUTQTII I IIDUO(JO.-----T~fl I~ ---~11=11 r IL TER r.lfD!A FOR O[WAr~HJNG POR::JUS BOTTOM CATCH BASIN INSERT NOTE: THIS OETA!L JS ONLY SCHEMATIC. ANY INSEflT IS ALLOWCO THAT tlAS A MJN. 0.5 C.F. OF STORAGE, THE MEAl>iS TO DEWATER THE STORED SEDIMENT, AN OVERFLOW, AND CAN BE EASILY MA]NTA!NED, 1 '=111=. 1::::11 =11i= '=II =111= ,Jffig ANY ACCUMULATED SEDIMENT ON OR AROUND THE F L TFR FABRIC SHALL BE REMOVED IMMEO[hTELY. SEDlM NT S!IALL I\QT BE RD.IOV[D WITH WATER, ANO All SE lf'1ENT MUST BE DISPOSED OF AS FILL m,-Sll!:. DR HAUL D OFF-SITF. 2. ANY SEDIMENT IN THE" CATCH 3ASIN INSERT SHALL BE REMOVED WHE~ THE SEDIMENT HAS FILLED ONE THIRD DF THE AVAILl,BLE STORAGE. TH!:. FILTER M!:.D IA FOR THE INSERT SHALL BE CLEANEC OR R.:'.PLACF.0 AT LEAST MONTHLY. 3. RE::;ULAR MAHHENANCE IS CRITICAL FOR [llJld f.ORMS oc-CATCH BASIN PROTECTIO!';. UNLIKE MANY FORMS OF PROTFt.TltlN THAT FAIL GRADUALLY, CATCH BAS1N PROTE.Cf!ON WILL FAIL SUDDENLY ANO COMPLETELY (F NOT MAlNTAINrn PROPERLY. FILTER FABRIC SKfRT SfCl;RHl WITH GRATC:\ COLLECTED SEDIMENT CATCH BASIN GRATE R[TRIEVA_ sm,1r OVERFLOW AL TERNA TE CATCH BASIN INSERT CATCH BASIN SEDIMENT CONTROL FOR 1/,,STALLATION. SEE TECHNIQUES FOR TEWORARY EROS:ON AND SEDCMENT CONTROL, PSE STANDARD 0150.3200 NTS GXD DETAIL '2 DESIGN AND INSTAL.LAT!ON SPECIFICATIONS 1, THE" GEOTEXTILE USED I.IUST MEET THE STANDARDS L:STEO BELOW. A COPY 0'" THE I.IANUFACTURER'S .'"ABRIC SPECIFICATIONS MUST B[ Al,"AICABLE ON SITE. AO<, ( ASTM 0· 4751) 30-100 SIEVE SIZE (C· 60-0.15 rrrnl FOR SLIT Fl~M 50-100 SIEVE SIZE IC 30-.J.15 rrrnl FOR CTHER FABRICS 0.02 SEC\ MIN. PERFOW..TD POLTE!lfnENE ORAl"'-GE n.Ell>IG. OIA>.lf:JO! iotlN. 2· LA'lGER li-W4 OC'IIATEfllNG Ollf"ICE. TIJEIN(J SH/IU OOUPLY WrTh ASThl ,~~7 J,ll[l M.SHTO M294. WATER PERI.IITTIV!TY IASTM 0-4491 l GRAB TENS!LE STRENGTl-l (ASTM 0-46321 180 LBS MIN. fOR DHiA STRENGTH FABR!C 100 LBS "1JN. fOR STAf.OARO STRENGIH ~A!:l~IC JOINTS IN FILTER FABRIC SHALL BE SPLICEC AT POSTS. USE STAPLES, WIRE RINGS, OR EQUIVALENT TO ATTACH FABRIC TO POSTS. GRAB TENS lLE ELDNGAT ION { ASTI.I 0-4632 l ULTRAVIOLET Ri':SISTANCE lASTI.I D-435S) 30'1. MAX. 70'!.. MIN. 2-STANDARD STRENGTH FABRIC RE~U!RES WIRE SACKING TO INCREASE THE STRENGTH OF THE F[NC[. WIRE BACKING OR CLOSER POST SPACING MAY BE REOUIRC:O FDR EXTRA STRENGTH FABRIC IF FIELD PERFORMANCE WARRANTS A STRONGER FENCE. 3. WHERE Tl-<E FE!>ICE IS INSTAil ED, THE SIOPE SHALL 3E NO STEEPER T~AN 2Ho1\/. mn= CORRUGAHO I.ICTAI.. fllSE:R I -=-:~~ ta" l,IN L __ ~.f~~-_r-- l_ I CONCRETE BASE I---1): RISER alA. Ml~. ----j J.~· MIN. C~'WAlclllr.lG ORIFlCE, 5':KEOLJL.: ~" STEEL sn.rn Mfj DW.IDm J.S Pm c:ALCUL>:10NS ALTrnt-lATMl.Y. MCTAL STAJ<.:s A,~D WIRE MAY BE US£[] TO PREVENT FLOTATION SEDIMENT POND RISER DETAIL EB :S'i'il~~ ~""'' ~t """ ----1.------.-. =".,_ • .,. " Ml~ ~~~E~T~~~Hg~ ~ -' _-:-:-:-:-=-1--=--'J =m oa c=, -"'" ~I~, I ~~ _-:-:-:-:-:-:-:-_::-. NOT B[ L5Ell. -~-=~\ CONCRCTE 11,!,51' (SU: RISER OETAJL) 111:iCl<M\.E TO STABII.JilD co~~EfMJCC. OUTLG OR LE'IFJ. SPRO.DER SEDIMENT POND~ SECTION ~ 2"x2" BY 14 GA w:RE OR ECUIVALENT. IF s-:-AN)A~O STRENGTH FABRIC USED. F. ILTER FABRIC z , 'n-~m*1] -7 Li )" u\---------,.:"::',:, ~",',:~",__/ I P:JST 5PACiNG llAY BE WITH NATlVE SOIL OR MAINTENANCE STANDARDS 1. ANv DAMAGE SHA~L BE REPAIRED lt.iMEO!ATEL Y 2. lF CONCENTRATED FLOWS ARE ~VIDENT UPHILL OF THE FE~CE, T~EY MUST BE INTERCEPTED ANO CONVEYED TO A SEOEMENT TRAP DR PONC. 3. 1T JS IMPORTANT TO CHECK TrlE UPHILL SJOE OF T~!:. FENCE FDR SIG,~S OF THE FC.NCE CLOGGING AND ACTING AS A BARRIER TO rLOW ANO ltl[N CAUSING CHANNELIZATION OF FLOWS PARALLEL TO THE FENCE. IF THIS OCCURS, REPLACE THE FENCE ANO/OR REMOVE T~.E TRAPPED SE:OIMENT. 4. SEDII.IENT l,lJST BE REMOVED WHEN IT iS b" HIGH. 5. IF THE FILTER FABRIC ~AS DETERIORATED DUE TO THE UL TRAV!OLET BREAKOOWf.:. IT SH/\LL BE REPLACED. 1Nr.r1[ASFO TO 8 IF WIRE ~,," 1 5' WASHED GRAVEL BACK !NG !S US~D NOTE: FILTER FABRIC FENCES SHALL BC l~STALLEO ALONG C'.INTOUR WHEN('l(A POS<,JBLE 2"x~ ·~ooc POSTS-STEEL FENCE POSTS. REBAR. OR Eou:VALrnT SILT FENCE DESIGN AND INSTALLATION SPECIFICATIONS AND MAINTENANCE STANDARDS DETAIL GXD '2 ! -, --';;~" HIGH DENSITY POLYETHYLENE OR POLYPROPYLENE MESH, ANO SHALL BE UV RESISTANT, ORANGE COLOR ELEVATION FC:NCE ON SLOPE = '4 ELEVATION POST SH/I.LL HAVE SUFFICIENT STRENGTH ANO DURABILITY TO SUPPORT THE FENCE THROUGH THE LIFE OF THE PROJECT. 2x2 WOOD POS"7" STAPLE TOP TIE SELF-LOCKING TIE NYLON 6/6 IM!N. GRADE). 50# I.IJN. 7ENS TLE STRENGTH, UV STABILIZED. STEEL T-BAH POST SELF-LOCK I NG TIE FENCING I.IA TEA JAL ', FENCING - MATERIAL / NYLON 6/6 ( l.l!N. GRADE I, SO# I.IJN. TENSl!..E STRENGTH, / ( ' ~ ii \ ~~~\Ii ' ' ' \ \ I I I I / I I I I \ \ ' -];-' ;:., )-' -" ~-----,,i"-__ /'- ( ~ \ / [ ' ' '-"!.:..'..I_........- / 1 '-0" M[N. <DEEPER FOR 0 ' \ I ' / ' / 2' -0" !DESIRABLE) UNSTABLE SOIL I~---- 2x2 WOOD OR ......_ UV STABILIZED ' \ I / // \ I I I ENV I RONr.tENTALL Y SENSITIVE AREA BOUNDARY STEEL T-BAR POST HIGH TYPICAL SECTION A VISIBILITY FENCE DETAIL ED]) '2 '@, CALL BEFORE ~ YOU DIG Co 11 : TOLL FREE , 1-B00-424-5555 " s ~,="~"~'°"~"~"~'"~'"~"'~"'~~~"=""="'="~"~"~22~'~"-~T=E=M=P=o=R=A=R=Y~E~R~O~S~I~o=N=/s=E=D=IM=E=N=T~c=o=N=T=R=O~L-,--, J. NelsoY\ C.,C:c15z I """" NOTES AND DETAILS TALBOT HILL SUBSTATION DATE !M/0/Y) 10 I IOI /Ye_ Jg lg!, 1/6 • SC~LE I NONE PUGET SOUND ENERGY jj____!_,__'i_l/tp l:•oo NO: 110GN0 SUBSTATION ENGINEERING DEPARWENT CL~Ss: SITE Of/AWING NU Rl¥ NU 0 This page intentionally left blank. Appendix G Facilities Summary and Declaration of Covenant 2009 Surface Water Design Manual KING COUNTY, WASIIII\GTON, SURFACE WATER DESIGN MA'JUAL KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-D FLOW CONTROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH 1/9/2009 KTI\G COUNTY, WASHINGTON, SURFACE WATER DESIGN MAI\CAL STORMW ATER FACILITY SUMMARY SHEET DOES Permit Number 1 -~------- (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Overview: Project Name _T_a_lb_o_t_S_u_b_s_ta_t_io_n_S_to_r_m_w_a_t_e_r _S_u~p~p_o_rt _________ Date September 28, 2016 Downstream Drainage Basins Major Basin NameD __ u_w_a_m~is_h---,----R_i_v~e_r _~~~---,------ Immediate Basin Name Project Area Subbasin Flow Control: Flow Control Facility Name/Number Stormwater Detention Pond --------------- Facility Location Southeastern corner of Talbot Substation ---------------------------------- If none, Flow control provided in regional/shared facility (give location) ____ ---,----__________ _ No flow control required Exemption number General Facility Information: Type/Number of detention facilities: Type/Number of infiltration facilities: __ 1_ponds ponds vaults tanks --- tanks trenches ------ Control Structure Location Control structure located on southern side of detention pond. Type of Control Structure 12 inch diameter riser structure Number of Orifices/Restrictions 3 Size of Orifice/Restriction: No. I 1. 15 inches No. 2 2. 13 inches ~~~==~-- No. 3 _2_.0_0_i_nc_h_e_s __ No. 4 ______ _ Flow Control Performance Standard Match forested condition for flows from 50% of the 2 year up to 100% of the 50-year 2009 Surface Water Design Manual 1 11912009 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL Live Storage Volume 73,876 Cubic Feet Depth 7.0 Ft (effect. storage)Volume Factor of Safety Number of Acres Served 5.89 acres Number of Lots 1 ---------- Dam Safety Regulations (Washington State Department of Ecology) Reservoir Volume above natural grade 73,876 above excavated grade. 27,124 above natural grade. Depth of Reservoir above natural grade 7.5 above excavated grade. 2.5 above natural grade. Facility Summary Sheet Sketch All detention, infiltration and water quality facilities must include a detailed sketch. (11 "xl 7" reduced size plan sheets may be used) 2009 Surface Water Design Manual 2 1/9/2009 LEGEND L.-' ""'! Project Area ·- • Conto urs - 10 ft Interval Prop o sed C ontrol Structure ~ P ro po sed Flow Path 5 E22l] Prop osed Dra i nage Infrastructure Proposed Detention Pond Pro po sed Access Roa d DATA SOURCE: City ex Renton, King Courl.y (20 16) 0 Feet 150 FLOW CONTROL FACILITY SKETCH APPENDIX G PJITH: O ·IPROJEC TS\WASHINOTON\PUQ[T_SOOND_fiNliAQY_00101'l\TAl 801_1f0RMWA TER_IUPPOAT_?tHHWAP' _OOCSo0ft.U:T\TtR FtOURU\APPEMOIX O FACILTY SKl!TCH.MXO • USER: TA HOF FMA • DATCi: 11111/2011 STORMWA TER TIR 2009 Surface Water Design Manual Amendment CITY OF RENTON AMENDMENTS TO THE KING COUNTY SURFACE WATER DESIGN MANUAL REFERENCE 8-H BOND QUANTITIES WORKSHEET City of Renton Site Improvement Bond Quantity Worksheet Original bond computations prepared by: Name: Date: --------------PE Registration Number: Te I.#; -----------Firm Name: Address: Project No: _____________ _ ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND•,h AMOUNT PUBLIC ROAD & DRAINAGE MAINTENANCE/DEFECT BOND*,0 Stabilization/Erosion Sediment Control (ESC) (A) $ Existing Right-of-Way Improvements (B) $ Future Public Road Improvements & Drainage Facilities (C) $ Private Improvements (D) $ Construction Bond* Amount (A+B+C+D) TOTAL (T) $ Minimum bond• amount is $1000. (B+C) x Maintenance/Defect Bond* Total 0.20 = _:$:___ _____ _ NAME OF PERSON PREPARING BOND" REDUCTION: * 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. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. REQUIRED BOND~ AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY RDSD Page 1 of 1 REF 8-H BOND QUANTITY WORKSHEET.xis Date· LJnij prices updated: 2112102 Version: 4/22/02 Report Date: 1119/2010 Site Improvement Bond Quantity Worksheet $ Backfill & Compaction-trench GI-2 $ 8.53 CY 0.00 Clear/Remove Brush, by hand GI -3 $ 0.36 SY 0.00 0.00 Clearing/Grubbing!Tree Removal Gl-4 $8,876 16 Acre 0.00 0.00 Excavation -bulk GI -5 $ 1.50 CY 0.00 0.00 Excavation -Trench Gl-6 $ 406 CY 0.00 0.00 Fencing, cedar, 6' high Gl-7 $ 18.55 LF 0.00 0.00 Fencing, chain link, vinyl coated, 6' high GI-B $ 13.44 LF 0.00 0.00 Fencing, chain link. gate, vinyl coated, 2 GI -9 $ 1.271.81 Each 0.00 0.00 Fencing, split rail, 3' high GI -1< $ 12.12 LF 0.00 0.00 Fill & compact -common barrow GI -11 $ 22.57 CY 0.00 0.00 Fill & compact -gravel base GI -1 $ 25.48 CY 0.00 0.00 Fill & compact -screened topsoil GI -1 $ 37.85 CY 0.00 0.00 Gabion, 12" deep, stone filled mesh GI -1 $ 54.31 SY 0.00 000 Gabion, 18" deep, stone filled mesh GI -1 $ 74.85 SY 0.00 0.00 Gabion, 36" deep, stone filled mesh GI -1 $ 132.48 SY 0.00 0.00 Grading, fine, by hand GI -1 $ 2.02 SY 0.00 0.00 Grading, fine, with grader GI -1 $ 0.95 SY 0.00 0.00 Monuments, 3' long GI -1 $ 135.13 Each 0.00 0.00 Sensitive Areas Sign GI -2 $ 2.88 Each 0.00 0.00 Sodding, 1" deep, sloped ground GI -21 $ 7.46 SY 0.00 0.00 Surveying, line & grade GI -2 $ 788.26 Day 0.00 0.00 Surveying, lot loc.ation/lines GI -2 $1,556.64 Acre 0.00 0.00 Traffic control crew ( 2 flaggers ) GI -2 $ 85.18 HR 000 0.00 Trail, 4" chipped wood GI -2 $ 7.59 SY 0.00 0.00 Trail, 4" crushed cinder Gl-2 $ 8.33 SY 0.00 0.00 Trail, 4" top course GI -2 $ 8.19 SY 0.00 0.00 Wall, retaining. concrete Gl-2 $ 44.16 SF 0.00 0.00 Wall, rockery IGl-2S $ 9.49 SF 0.00 o.oc Page 2 of 7 SUBTOTAL 0.00 0.00 --- REF 8-H BOND QUANTITY WORKSHEET.xis 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 Unit prices updated: 2/12/02 Version: 4/22102 Report Date: 111912010 Site Improvement Bond Quantity Worksheet AC Grinding, 4' wide machine< 1000sy RI -1 $ 23.00 SY 0.00 AC Grinding, 4' wide machine 1000-2000 RI· 2 $ 5.75 SY 0.00 0.00 AC Grinding, 4' wide machine > 2000sy RI· 3 $ 1.38 SY 0.00 0.00 AC Removal/Disposal/Repair RI -4 $ 41.14 SY 0.00 0.00 Barricade, type I RI· 5 $ 3003 LF 0.00 0.00 Barricade, type 111 ( Permanent ) RI -6 $ 45.05 LF 0.00 0.00 Curb & Gutter, rolled RI -7 $ 13.27 LF 0.00 0.00 Curb & Gutter, vertical RI· 8 $ 9.69 LF 0.00 0.00 Curb and Gutter, demolition and disposal RI -9 $ 13.58 LF 0.00 0.00 Curb, extruded asphalt RI· 10 $ 2.44 LF 0.00 0.00 Curb, extruded concrete RI · 11 $ 2.56 LF 0.00 0.00 Sawcut, asphalt, 3" depth RI -1 $ 1.85 LF 0.00 ODO Sawcut. concrete, per 1" depth RI· 13 $ 1.69 LF ODD 0.00 Sealant, asphalt RI· 14 $ 0.99 LF 0.00 0.00 Shoulder, AC, { see AC road unit price ) RI -15 $ . SY 0.00 0.00 Shoulder, gravel, 4" thick RI -1 $ 7.53 SY 0.00 0.00 Sidewalk, 4" thick RI· 1 $ 30.52 SY 0.00 0.00 Sidewalk, 4" thick, demolition and dispos RI· 1 $ 27.73 SY 0.00 0.00 Sidewalk, 5" thick RI· 19 $ 34.94 SY 0.00 0.00 Sidewalk, 5" thick, demolition and dispos RI-2 $ 34.65 SY 0.00 0.00 Sign, handicap RI· 21 $ 85.28 Each 0.00 0.00 Striping, per stall RI· 22 $ 5.82 Each 0.00 0.00 Striping, thermoplastic, ( for crosswalk ) RI· 23 $ 2.38 SF 0.00 0.00 ~tnping, 4" renectorized 11ne 1,1 -L4 • 0.25 LF 0.00 O.<>< Page 3 of 7 SUBTOTAL 0.00 0.00 REF 8-H BOND QUANTITY WORKSHEET.xis 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 Unit prices updated: 2/12/02 Version: 4122/02 Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet $ 3.60 SY 0()0 0.00 AC Overlay, 1.5" AC RS-2 $ 7.39 SY 0.00 0.00 AC Overlay, 2'' AC RS-3 $ 8.75 SY 0.00 0.00 AC Road, 2", 4" rock, First 2500 SY RS-4 $ 17.24 SY 0.00 0.00 AC Road, 2", 4" rock, Qty. over 2500SY RS-5 $ 13.36 SY 0.00 0.00 AC Road, 3", 4" rock, First 2500 SY RS-6 $ 19.69 SY 0.00 0.00 AC Road, 3", 4" rock, Qty. over 2500 SY RS-7 $ 15.81 SY 0.00 0.00 AC Road, 5", First 2500 SY RS -8 $ 14.57 SY 0.00 0.00 AC Road, 5", Qty. Over 2500 SY RS -9 $ 13.94 SY 0.00 0.00 AC Road, 6", First 2500 SY ,s-1 $ 16.76 SY 0.00 0.00 AC Road, 6", Qty. Over 2500 SY as -1 $ 16.12 SY 0.00 0.00 Asphalt Treated Base. 4" thick SS-1 $ 9.21 SY 0.00 0.00 Gravel Road, 4" rock, First 2500 SY S -1 $ 11.41 SY 0.00 0.00 Gravel Road, 4" rack, Qty. over 2500 SY S -1 $ 7.53 SY 0.00 0.00 PCC Road, 5", no base, over 2500 SY S -1 $ 21.51 SY 0.00 0.00 PCC Road, 6'', no base, over 2500 SY as-1 $ 21.87 SY 0.00 0.00 1 r 11cKened n 1ge Page4 of7 SUBTOTAL 0.00 0.00 REF 8-H BOND QUANTITY WORKSHEET.xis 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Unit prices updated: 2/12/02 Version: 4/22/02 Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet Bollards -removable I 0-3 I $ 452.34 I Each I I 0.001 I 0.001 I * (CBs include frame and lid) CB Type I 0-4 $1,25764 Each 0.00 0.00 CB Type IL 0-5 $1,433.59 Each 0.00 0.00 CB Type ll, 48" diameter 0-6 $2,033 57 Each 0.00 0.00 for additional depth over 4' 0-7 $ 43652 FT 0.00 0.00 CB Type II, 54" diameter 0 -8 $2,192.54 Each 0.00 0.00 for additional depth over 4' 0 -9 $ 486.53 FT 0.00 0.00 CB Type H, 60" diameter D -10 $2,351.52 Each 0.00 0.00 for additional depth over 4' 0 -11 $ 53654 FT 0.00 0.00 CB Type II, 72" diameter 0 -12 $3,212.54 Each 0.00 0.00 for additional depth over 4' 0 -13 $ 692.21 FT 0.00 0.00 Through-curb Inlet Framework {Add) 0 -14 $ 366.09 Each 0.00 0.00 Cleanout, PVC, 4" D -15 $ 130.55 Each 0.00 0.00 Cleanout, PVC, 6" 0-16 $ 174.90 Each 0.00 0.00 Cleanout, PVC, 8" 0-17 $ 224.19 Each 0.00 0.00 Culvert, PVC, 4" D-18 $ 8.64 LF 0.00 0.00 Culvert, PVC, 6" 0 -19 $ 12.60 LF 0.00 0.00 Culvert, PVC, 8" 0-20 $ 13.33 LF 0.00 0.00 Culvert, PVC, 12" 0-21 $ 21.77 LF 0.00 0.00 Culvert, CMP, 8" 0-22 $ 17.25 LF 0.00 0.00 Culvert, CMP, 12" D-23 $ 26.45 LF 0.00 0.00 Culvert, CMP, 15" 0-24 $ 32.73 LF 0.00 0.00 Culvert, CMP, 18" 0-25 $ 37.74 LF 0.00 0.00 Culvert, CMP, 24" D-26 $ 53.33 LF 0.00 0.00 Culvert, CMP, 30" D-27 $ 71.45 LF 0.00 0.00 Culvert, CMP, 36" D-28 $ 112.11 LF 0.00 0.00 Culvert, CMP, 48" 0-29 $ 140.83 LF 0.00 0.00 Culvert, CMP, 50" D-30 $ 235.45 LF 0.00 0.00 rt, v1v1r· , 1 £ LJ -" :ti .:>V£.5ts Le U.u, U. Page 5 of 7 SUBTOTAL 0.00 0.00 REF 8-H BOND QUANTITY WORKSHEET.xis 0001 I 0.00 -.. .... 0.00 -0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ODO 0.00 0.00 ODO 0.00 0.00 --------- Unit prices updated: 2/12/02 Version: 4/22/02 Report Date: 1/19/2010 Site Improvement Bond Quantity Worksheet $ 30.05 LF 0 0 0-34 $ 37.34 LF 0 0 Culvert, Concrete, 18" 0-35 $ 44.51 LF 0 0 Culvert, Concrete, 24" 0-36 $ 61.07 LF 0 0 Culvert, Concrete, 30" 0-37 $ 104.18 LF 0 0 Culvert, Concrete, 36" 0-38 $ 137.63 LF 0 0 Culvert. Concrete, 42" 0-39 $ 158.42 LF 0 0 Culvert, Concrete, 48" D-40 $ 175.94 LF 0 0 Culvert, CPP, 6" 0-41 $ 10.70 LF 0 0 Culvert, CPP, 8" 0-42 $ 16.10 LF 0 0 Culvert, CPP, 12" D-43 $ 20.70 LF 0 0 Culvert, CPP, 15" 0-44 $ 23.00 LF 0 0 Culvert, CPP, 18" D-45 $ 27.60 LF 0 0 Culvert, CPP, 24" D-46 $ 36.80 LF 0 0 Culvert, CPP, 30" 0-47 $ 48.30 LF 0 0 Culvert, CPP, 36" 0-48 $ 55.20 LF 0 0 Ditching 0-49 $ 8.08 CY 0 0 Flow Dispersal Trench (1,436 base+) 0-50 $ 25.99 LF French Drain (3' depth) 0-51 $ 22.60 LF 0 0 Geotextile, laid in trench, polypropylene 0-52 $ 2.40 SY 0 0 Infiltration pond testing 0-53 $ 74.75 HR 0 0 Mid-tank Access Riser, 48" dia, 6' deep D -54 $1,605.40 Each 0 0 Pond Overflow Spillway 0 -55 $ 14.01 SY 0 0 Restrictor/Oil Separator, 12" 0-56 $1,045.19 Each 0 0 Restrictor/Oil Separator, 15" 0-57 $1,095.56 Each 0 0 Restrictor/Oil Separator, 18" 0-58 $1,146.16 Each 0 0 Riprap, placed D-59 $ 3908 CY 0 0 Tank End Reducer (36" diameter) 0-60 $1,000.50 Each 0 0 (Trash Rack, 12" D-61 $ 211.97 Each 0 0 0-62 $ 237.27 Each 0 0 $ 268.89 Each 0 0 I rasn K8CK, Ll I u -041 :l) .>U<.i.ti4 cau ' ( Page 6 of7 SUBTOTAL 0 0 REF 8-H BOND QUANTITY WORKSHEET.xis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ' 0 lJ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 l 0 Unit prices updated: 2/12/02 Version: 4/22/02 Report Date: 111912010 Site Improvement Bond Quantity Worksheet No. 2" AC, 2'' top course rock & 4" borrow PL-1-$ 15.84 SY 0 0 2" AC, 1.5" top course & 2.5" base cour PL-2 $ 17.24 SY 0 0 4" select borrow PL-3 $ 4.55 SY 0 0 1.5" top course rock & 2.5" base course PL-4 $ 11.41 SY 0 0 l(Such as detention/water quality vaults.) No. W1 -1 Each 0 0.00 W1. 2 SY 0 0.00 W1. 3 CY 0 0.00 Wl-4 LF 0 0.00 W1. 5 FT 0 0.00 W1. 6 0 0.00 W1. 7 0 0.00 W1. 8 0 0.00 W1. 9 0 0.00 WI -10 \ o.uo SUBTOTAL 0.00 0.00 SUBTOTAL (SUM ALL PAGES): 0.00 0.00 30% CONTINGENCY & MOBILIZATION: 0.00 0.00 GRANDTOTAL: 0.00 0 00 COLUMN: B C Page 7 of 7 REF 8-H BONO QUANTITY WORKSHEET.xis 0 0 0 0 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 U.v 0.00 0.00 0.00 0.00 D 0 0 0 0 .. -;,._,,:- 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 E Unit prices updated: 2/12/02 Version: 4/22/02 Report Date: 1/19/2010 This page intentionally left blank. Appendix H Operations and Maintenance Manual The following manual includes a brief description of each facility and component requiring periodic maintenance at the project area. It also details the recommended frequency of maintenance activities and refers to the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities. Facility Description Recommended Frequency of Maintenance Detention The proposed stormwater Perform maintenance tasks listed in Pond detention pond is located along No. 1 -Detention Ponds of the the southeastern corner of the Maintenance Requirements for Flow substation. It is used to control Control, Conveyance, and WQ flow rates exiting the proposed Facilities after significant storm events. facility and prevent downstream erosion. Control Control structures are placed Perform maintenance tasks listed in Structure within or adjacent to No. 4 -Control Structure I Flow stormwater detention ponds Restrictor of the Maintenance and are the facilities which Requirements for Flow Control, restrict runoff from exiting the Conveyance, and WQ Facilities after stormwater detention oond. sianificant storm events. Conveyance Conveyance pipes are placed Perform maintenance tasks listed in Pipes within the substation and are No. 6 -Conveyance Pipes and Ditches used to convey water to the of the Maintenance Requirements for proposed stormwater detention Flow Control, Conveyance, and WQ nond. Facilities after sianificant storm events. Debris A debris barrier is placed within Perform maintenance tasks listed in Barriers the stormwater detention pond No. 7 -Debris Barries of the at the inlet to the control Maintenance Requirements for Flow structure. This prevents trash Control, Conveyance, and WQ and other foreign objects from Facilities after significant storm events. entering the structure and damaaina or blockina it. Fencing Fencing is placed around the Perform maintenance tasks listed in perimeter of the stormwater No. 9 -Fencing of the Maintenance detention pond and substation Requirements for Flow Control, to prevent unauthorized Conveyance, and WQ Facilities during individuals from entering the all site visits. facilities. Access An access road along the Perform maintenance tasks listed in Roads southern side of the substation No. 12 -Access Roads of the is used to gain vehicle access Maintenance Requirements for Flow to the site. Control, Conveyance, and WQ Facilities after sianificant storm events. KING COUNTY, WASHINGTON, SURFACE WATER lJESICi'i MANUAL KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE AND WQ FACILITIES 1/9/2009 KING COUNTY, WASHINGTON. SURFACE WATER DESIGN MAI\CAL APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES Relevant facilities and components have been outlined in red. This appendix contains the maintenance requirements for the following typical stormwater control facilities and components: I No. 1 -Detention Ponds (p. A-2) I No. 2 -Infiltration Facilities (p. A-3) No. 3 -Detention Tanks and Vaults (p. A-5) I No. 4 -Control Structure!Flow Restrictor (p. A-7)! No. 5 -Catch Basins and Manholes (p. A-9) No. 6-Conveyance Pipes and Ditches (p. A-11) No. 7 -Debris Barriers (e.g., Trash Racks) (p. A-12) No. 8 -Energy Dissipaters (p. A-13) !No. 9-Fencing (p. A-14)! No. IO -Gates/Bollards/ Access Barriers (p. A-15) No. 11 -Grounds (Landscaping) (p. A-16) !No. 12-Access Roads (p. A-17)! No. 13 -Basic Biofiltration Swale (grass) (p. A-18) No. 14-Wet Biofiltration Swale (p. A-19) No. 15 -Filter Strip (p. A-20) No. 16-Wetpond (p. A-21) No. 17 -Wetvault (p. A-23) No. 18 -Stormwater Wetland (p. A-24) No. 19 -Sand Filter Pond (p. A-26) No. 20 -Sand Filter Vault (p. A-28) No. 21 -Stormfilter (Cartridge Type) (p. A-30) No. 22 -Baffle Oil/Water Separator (p. A-32) No. 23 -Coalescing Plate Oil/Water Separator (p. A-33) No. 24 -Catch Basin Insert (p. A-35) 2009 Surface Water Design Manual-Appendix A A-1 11912009 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ fACILITIES - NO. 1 -DETENTION PONDS Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Top or Side Slopes Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and of Dam, Berm or as a dam or berm, or any evidence of water dam or berm repaired. Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of slopes, does Trees do not hinder facility not allow maintenance access, or interferes with performance or maintenance maintenance activity. If trees are not a threat or activities. not interfering with access or maintenance, they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has Top or side slope restored to design settled 4 inches lower than the design elevation. dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment Accumulated sediment that exceeds 10% of the Sediment cleaned out to designed accumulation designed pond depth. pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged Liner is visible or pond does not hold water as Liner repaired or replaced. (If Applicable) designed. Inlet/Outlet Pipe. Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. Emergency Tree growth Tree growth impedes flow or threatens stability of Trees removed. Overflow/Spillway spillway. Rock missing Only one layer of rock exists above native soil in Spillway restored to design area five square feet or larger or any exposure of standards. native soil on the spillway. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-2 APPENDIX A MAl!sTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIP.S ---- NO. 2-INFILTRATION FACILITIES Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other lhan a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Infiltration Pond, Top Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and or Side Slopes of as a dam or berm, or any evidence of water dam or berm repaired. Dam, Berm or piping through dam or berm via rodent holes. Embankment Tree growth Tree growth threatens integrity of dams, berms or Trees do not hinder facility slopes, does not allow maintenance access, or performance or maintenance interferes with maintenance activity. If trees are activities. not a threat to dam, berm, or embankment integrity or not interfering with access or maintenance, they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has Top or side slope restored to design settled 4 inches lower than the design elevation. dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Infiltration Pond, Sediment If two inches or more sediment is present or a Facility infiltrates as designed. Tank, Vault, Trench, accumulation percolation test indicates facility is working at or or Small Basin less than 90% of design. Storage Area Infiltration Tank Plugged air vent Any blockage of the vent. Tank or vault freely vents. Structure Tank bent out of Any part of tank/pipe is bent out of shape more Tank repaired or replaced to design. shape than 10% of its design shape. Gaps between A gap wider than 1h-inch at the joint of any tank No water or soil entering tank sections, damaged sections or any evidence of soil particles entering through joints or walls. joints or cracks or the tank at a joint or through a wall. tears in wall Infiltration Vault Damage to wall, Cracks wider than X-inch, any evidence of soil Vault is sealed and structurally Structure frame, botlom, and/or entering the structure through cracks or qualified sound. top slab inspection personnel determines that the vault is not structurally sound. 2009 Surface Water Design Manual-Appendix A 1/9/2009 A-3 Al'l'ENlJlX A MAll\TENANCE REQlllREMEI\TS Fl.OW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 2 -INFILTRATION FACILITIES Maintenance Defect or Problem Conditions When Maintenance Is Needed Results Expected When Component Maintenance Is Performed Inlet/Outlet Pipes Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. al the joints of the inlet/outlet pipes. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and covers access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. Infiltration Pond, Plugged Filter bag more than 1/2 full. Replace filter bag or redesign Tank, Vault, Trench, system. or Small Basin Filter Bags Infiltration Pond, Sediment 6" or more of sediment has accumulated. Pre-settling occurs as designed Tank, Vault, Trench, accumulation or Small Basin Pre- settling Ponds and Vaults Infiltration Pond, Plugged High water level on upstream side of filter Rock filter replaced evaluate need Rock Filter remains for extended period of time or little or no for fitter and remove if not water flows through filter during heavy rain necessary. storms. Infiltration Pond Rock missing Only one layer of rock exists above native soil in Spillway restored to design Emergency Overflow area five square feet or larger, or any exposure of standards. Spillway native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. Tree growth Tree growth impedes flow or threatens stability of Trees removed. spillway. 119/2009 2009 Surface Water Design Manual -Appendix A A-4 Al'l'ENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, Al\D WQ FACILITIES ·--·- NO. 3-DETENTION TANKS AND VAULTS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline. concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater lhan 6 inches. Tank or Vault Trash and debris Any trash and debris accumulated in vault or tank No trash or debris in vaull. Storage Area (includes floatables and non-floatables). Sediment Accumulated sediment depth exceeds 10% of the All sediment removed from storage accumulation diameter of the storage area for% length of area. storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than % length of tank. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of Any part of tank/pipe is bent out of shape more Tank repaired or replaced to design. shape than 10% of its design shape. Gaps between A gap wider than %-inch at the joint of any tank No water or soil entering tank sections, damaged sections or any evidence of soil particles entering through joints or walls. joints or cracks or the tank at a joint or through a wall. tears in wall Vault Structure Damage to wall, Cracks wider than %-inch, any evidence of soil Vault is sealed and structurally frame, boltom, and/or entering the structure through cracks or qualified sound. top slab inspection personnel detennines that the vault is not structurally sound. Inlet/Outlet Pipes Sediment Sediment filling 20% or more of the pipe. lnlel/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlel/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %-inch at the joint of the No cracks more than Xi-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inletloutlet pipe. at the joints of the inlet/outlet pipes. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-5 APPENDIX A MAINTENANCE RE()UIREMENTS rl .OW CONTROL, CONVEYANCE, AND W() FACILITIES NO. 3-DETENTION TANKS AND VAULTS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools. Bolts cannot be sealed. Self-locking cover/lid does not work. Cover/lid difficull to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and covers access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 1/9/2009 2009 Surface Water Design Manual -Appendix A J\-6 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL. CONVEYANCE. AND WQ FACILITIES NO. 4-CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Trash and debris Trash or debris of more than ~ cubic foot which No Trash or debris blocking or is located immediately in front of the structure potentially blocking entrance to opening or is blocking capacity of the structure by structure. more than 10%. Trash or debris in the structure that exceeds 1h No trash or debris in the structure. the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Sediment Sediment exceeds 60% of the depth from the Sump of structure contains no bottom of the structure to the invert of the lowest sediment. pipe into or out of the structure or the bottom of the FROP~ T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Damage to frame Corner of frame extends more than% inch past Frame is even with curb. and/or top slab curb face into the street (If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than X. inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than Y. inch of the frame from the top slab. Cracks in walls or Cracks wider than % inch and longer than 3 feet, Structure is sealed and structurally bottom any evidence of soil particles entering structure sound. through cracks, or maintenance person judges that structure is unsound. Cracks wider than % inch and longer than 1 foot No cracks more than 1/4 inch wide at at lhe joint of any inleUoutlet pipe or any evidence the joint of inleUoutlet pipe. of soil particles entering structure through cracks. Settlemenu Structure has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than %-inch at the joint of the No cracks more than X-inch wide al inleUoutlet pipes or any evidence of soil entering the joint of inleUoutlet pipes. the structure at the joint of the inleUoutlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing Ladder is unsafe due to missing rungs, Ladder meets design standards and or unsafe misalignment, rust, cracks, or sharp edges. allows maintenance person safe access. FROP-T Section Damage T section is not securely attached to structure T section securely attached to wall wall and outlet pipe structure should support at and outlet pipe. least 1,000 lbs of up or down pressure. Structure is not in upright position (allow up to Structure in correct position. 10% from plumb). Connections to outlet pipe are not watertight or Connections to outlet pipe are water show signs of deteriorated grout. tight; structure repaired or replaced and works as designed. Any hote~ther than designed holes-in the Structure has no holes other than structure. designed holes. Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. 2009 Surface Water Design Manual -Appendix A l/9/2009 A-7 APPEJ\f)JX A MAINTEl\ANCt REQUIREMENTS ELOW CONTROL, CONVEYANCE, AND WQ EACILITIES .. , NO. 4 -CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Pelformed Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and down easily and maintenance person. is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing Control device is not working properly due to Plate is in place and works as missing, out of place. or bent orifice plate. designed. Obstructions Any trash, debris, sediment, or vegetation Plate is free of all obstructions and blocking the plate. works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the Pipe is free of all obstructions and potential of blocking) the overflow pipe. works as designed. Deformed or damaged Up of overflow pipe is bent or deformed. Overflow pipe does not allow lip overflow at an elevation lower than design lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than Y:,-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. Metal Grates Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design (If Applicable) standards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and Remove cover/lid after applying 80 lbs. of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-8 APPEl\DIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES - NO. 5 -CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60% of the depth from the Sump of catch basin contains no bottom of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of lhe invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than Y2 cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. 1 /3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases (e.g., methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Corner of frame extends more than % inch past Frame is even with curb. and/or top slab curb face into the street (If applicable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than X inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than% inch of lhe frame from the top slab. Cracks in walls or Cracks wider than X inch and longer than 3 feet. Catch basin is sealed and bottom any evidence of soil particles entering catch structurally sound. basin through cracks, or maintenance person judges that catch basin is unsound. Cracks wider than Yz inch and longer than 1 foot No cracks more than 1/,. inch wide at at the joint of any inleVoutlet pipe or any evidence the joint of inleUoutret pipe. of soil particles entering catch basin through cracks. Settlement/ Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than X-inch at the join! of the No cracks more than Y..-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the catch basin at the joint of the inleUoutlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. I nleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. lnletloutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than X-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering lhe joint of the inlet/outlet pipe. al the joints of the inleUoutlet pipes. 2009 Surface Water Design Manual-Appendix A 1/9/2009 A-9 APPENDIX A MAINTENAI\CE REQUIREMENTS FLOW CONTROL, CONVEYANCE, ANlJ WQ FACILITIES ' NO. 5 -CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Metal Grates Unsafe grate opening Grate with opening wider than 7 /8 inch. Grate opening meets design (Catch Basins) standards. Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design Any open structure requires urgent standards. maintenance. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and Remove cover/lid after applying 80 lbs. of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-10 APPENDIX;\ Mi\INTEN/\'ICE RFQIIIREMENTS FOR fl.OW CONTROL, CONVEYANCE. AKO WQ fi\CILITIES NO. 6-CONVEYANCE PIPES AND DITCHES Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment & debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20% of the diameter of the pipe. Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes. water through pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective Protective coating is damaged; rust or corrosion Pipe repaired or replaced. coating or corrosion is weakening the structural integrity of any part of pipe. Damaged Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20% of the Ditch cleaned/flushed of all sediment accumulation design depth. and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards. place or missing (If area 5 square feet or more, any exposed native Applicable) soil. 2009 Surface Water Design Manual -Appendix A [/9/2009 A-11 Al'l'ENDIX A MAINTENANCE REQlllREMENTS fLOW CONTROL, CONVEYANCE, A1'D WQ FACILITIES NO. 7 -DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed. Site Trash and debris Trash or debris plugging more than 20% of the Barrier clear to receive capacity flow. area of the barrier. Sediment Sediment accumulation of greater than 20% of Barrier clear to receive capacity flow. accumulation the area of the barrier Structure Cracked broken or Structure which bars attached to is damaged -Structure barrier attached to is loose pipe is loose or cracked or concrete structure is sound. cracked, broken of loose. Bars Bar spacing Bar spacing exceeds 6 inches. Bars have at most 6 inche spacing. Damaged or missing Bars are bent out of shape more than 3 inches. Bars in place \Mth no bends more bars than% inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars are loose and rust is causing 50% Repair or replace barrier to design deterioration to any part of barrier. standards. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-12 APPENDIX A MAINTENA'JCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIF.S ---------···· ··--------· NO. 8-ENERGY DISSIPATERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed. Site Trash and debris Trash and/or debris accumulation. Dissipater clear of trash and/or debris. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BM Ps implemented if appropriate. No contaminants present other than a surface oil film. Rock Pad Missing or moved Only one layer of rock exists above native soil in Rock pad prevents erosion. Rock area five square feet or larger or any exposure of native soil. Dispersion Trench Pipe plugged with Accumulated sediment that exceeds 20% of the Pipe cleaned/flushed so that it sediment design depth. matches design. Not discharging water Visual evidence of water discharging at Water discharges from feature by properly concentrated points along trench (normal sheet flow. condition is a "sheet flow'' of water along trench). Perforations plugged. Over 1/4 of perforations in pipe are plugged with Perforations freely discharge flow. debris or sediment. Water flows out top of Water flows out of distributor catch basin during No flow discharges from distributor "distributor" catch any storm less than the design storm. catch basin. basin. Receiving area over-Water in receiving area is causing or has No danger of landslides. saturated potential of causing landslide problems. Gabions Damaged mesh Mesh of gabion broken, twisted or deformed so Mesh is intact, no rock missing. structure is weakened or rock may fall out. Corrosion Gabion mesh shows corrosion through more than All gabion mesh capable of 1/.ii of its gage. containing rock and retaining designed form. Collapsed or Gabion basket shape deformed due to any All gabion baskets intact, structure deformed baskets cause. stands as designed. Missing rock Any rock missing that could cause gabion to No rock missing. loose structural integrity. Manhole/Chamber Worn or damaged Structure dissipating flow deteriorates to % or Structure is in no danger of failing. post, baffles or side of original size or any concentrated worn spol chamber exceeding one square foot which would make structure unsound. Damage to wall, Cracks wider than %-inch or any evidence of soil Manhole/chamber is sealed and frame, bottom, and/or entering the structure through cracks, or structurally sound. lop slab maintenance inspection personnel determines that the structure is not structurally sound. Damaged pipe joinls Cracks wider than %-inch at the joint of the No soil or water enters and no water inlet/outlet pipes or any evidence of soil entering discharges at the joint of inlet/outlet the structure at the joint of the inlet/outlet pipes. pipes. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-13 APPENDIX A MAINTENANCE REQUIREMENIS FLOW CONTROL, CONVEYANCE, ANO WQ EACII.ITIES NO. 9 -FENCING Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Erosion or holes Erosion or holes more than 4 inches high and 12-No access under the fence. under fence 18 inches wide permitting access through an opening under a fence. Wood Posts, Boards Missing or damaged Missing or broken boards, post out of plumb by No gaps on fence due to missing or and Cross Members parts more than 6 inches or cross members broken broken boards, post plumb to within 1 X inches, cross members sound. Weakened by rotting Any part showing structural deterioration due to All parts of fence are structurally or insects rotting or insect damage sound. Damaged or failed Concrete or metal attachments deteriorated or Post foundation capable of post foundation unable to support posts. supporting posts even in strong wind. Metal Posts. Rails Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1 % inches. and Fabric Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top rails, and Fence is aligned and meets design fabric) more than 1 foot out of design alignment. standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or Part or parts that have a rusting or scaling Structurally adequate posts or parts protective coating condition that has affected structural adequacy. with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50% of diameter ball could fit through. grid size. 1/9/2009 2009 Surface Water Design Manual~ Appendix A A-14 APPENDIX A MAIJ\TENANCE REQUIREMENTS HJR FLOW CONTROL, CONVEYANCE, AND WQ PACILITIES - NO. 10 -GA TES/BOLLARDS/ACCESS BARRIERS Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Chain Link Fencing Damaged or missing Missing gate. Gates in place. Gate members Broken or missing hinges such that gate cannot Hinges intact and lubed. Gate is be easily opened and closed by a maintenance working freely. person. Gate is out of plumb more than 6 inches and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in place. Locking mechanism Locking device missing, no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Openings in fabric Openings in fabric are such that an 8-inch Fabric mesh openings within 50% of diameter ball could fit through. grid size. Bar Gate Damaged or missing Cross bar does not slNing open or closed, is Cross bar swings fully open and cross bar missing or is bent to where it does not prevent closed and prevents vehicle access. vehicle access. Locking mechanism Locking device missing, no-functioning or does Locking mechanism prevents does not lock gate not link to all parts. opening of gate. Support post Support post does not hold cross bar up. Cross bar held up preventing vehicle damaged access into facility. Bollards Damaged or missing Bollard broken, missing, does not fit into support No access for motorized vehicles to hole or hinge broken or missing. get into facility. Does not lock Locking assembly or Jock missing or cannot be No access for motorized vehicles to attached to rock bollard in place. get into factlity. Boulders Dislodged Boulders not located to prevent motorized vehicle No access for motorized vehicles to access. get into facility. Circumvented Motorized vehicles going around or between No access for motorized vehicles to boulders. get into facility. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-15 Al'l'ENlJIX A MAINTENANCE REQu!REMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO, 11 -GROUNDS (LANDSCAPING) Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Perlormed Site Trash or litter Any trash and debris which exceed 1 cubic foot Trash and debris cleared from site. per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree identified as having a No hazard trees in facility. potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than 5% broken which affect more than 25% of the total of total foliage with split or broken foliage of the tree or shrub. limbs. Trees or shrubs that have been blown down or No blown down vegetation or knocked over. knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately Tree or shrub in place and supported or are leaning over, causing exposure adequately supported; dead or of the roots. diseased trees removed. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-I6 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL CONVEYANCE, AND WQ FACILITIES ' , ____ NO. 12 -ACCESS ROADS Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway drivable by maintenance square feet (i.e., trash and debris would fill up vehicles. one standards size garbage can). Debris which could damage vehicle tires or Roadway drivable by maintenance prohibit use of road. vehicles. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Blocked roadway Any obstruction which reduces clearance above Roadway overhead clear to 14 feet road surface to less than 14 feet. high, Any obstruction restricting the access to a 10-to At Jeasl 12-foot of width on access 12 foot width for a distance of more than 12 feet road. or any point restricting access to less than a 10 foot width. Road Surface Erosion, settlement, Any surface defect which hinders or prevents Road drivable by maintenance potholes, soft spots, maintenance access. vehicles. ruts Vegetation on road Trees or other vegetation prevent access to Maintenance vehicles can access surface facility by maintenance vehicles. facility. Shoulders and Erosion Erosion within 1 foot of lhe roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or Weeds and brush cut to 2 inches in hinder maintenance access. height or cleared in such a way as to allow maintenance access. Modular Grid Contaminants and Any evidence of conlaminants or pollution such Materials removed and disposed of Pavement pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing Access surface compacted because of broken on Access road surface restored so missing modular block. road infiltrates. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A,17 J\l'l'ENDIX A MAINTENANCE REQlllREMFI\TS PLOW CONTROL. CONVEYANCE. AND WQ FACILITIES - NO. 13 -BASIC BIOFIL TRA TION SWALE (GRASS) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Perlormed Site Trash and debris Any trash and/or debris accumulated on the No trash or debris on the bioswale bioswale site. site. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Swale Section Sediment Sediment depth exceeds 2 inches in 10% of the No sediment deposits in grass accumulation swale treatment area. treatment area of the bioswale. Sediment inhibits grass growth over 10% of Grass growth not inhibited by swale length. sediment. Sediment inhibits even spreading of flow. Flow spreads evenly through swale Erosion/scouring Eroded or scoured swale bottom due to No eroded or scoured areas in channelization or high flows. bioswale. Cause of erosion or scour addressed. Poor vegetation Grass is sparse or bare or eroded patches occur Swale has no bare spots and grass coverage in more than 10% of the swale bottom. is thick and healthy. Grass too tall Grass excessively tall (greater than 1 O inches), Grass is between 3 and 4 inches tan, grass is thin or nuisance weeds and other thick and healthy. No clippings left vegetation has taken over. in swale. No nuisance vegetation present. Excessive shade Grass growth is poor because sunlight does not Health grass growth or swale reach swale. converted to a wet bioswale. Constant baseflow Continuous flow through the swale, even when it Baseflow removed from swale by a has been dry for weeks or an eroded, muddy low-flow pea-gravel drain or channel has formed in the swale bottom. bypassed around the swale. Standing water Water pools in the swale between storms or does Swale freely drains and there is no not drain freely. standing water in swale between storms. Channelization Flow concentrates and erodes channel through No flow channels in swale. swale. Flow Spreader Concentrated flow Flow from spreader not uniformly distributed Flows are spread evenly over entire across entire swale width. swale width. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. fnleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks 'Wider than 12-inch at the joint of the No cracks more than Xi-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. l/912009 2009 Surface Water Design Manual -Appendix A A-18 APPENDIX A Mi\INTENAJ\CE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES N0.14-WET BIOFILTRATION SWALE Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and/or debris accumulated at the site. No trash or debris at the site. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline. concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Swale Section Sediment Sediment depth exceeds 2 inches in 10% of the No sediment deposits in treatment accumulation swale treatment area. area. Erosion/scouring Eroded or scoured swale bottom due to No eroded or scoured areas in channelization or high flows. bioswale. Cause of erosion or scour addressed. Water depth Water not retained to a depth of about 4 inches Water depth of 4 inches through out during the wet season. swale for most of wet season. Vegetation ineffective Vegetation sparse, does not provide adequate Wetland vegetation fully covers filtration or crowded out by very dense clumps of bottom of swale and no cattails or cattail or nuisance vegetation. nuisance vegetation present. Insufficient water Wetland vegetation dies due to lack of water. Wetland vegetation remains healthy (may require converting to grass lined bioswale Flow Spreader Concentrated flow Flow from spreader not uniformly distributed Flows are spread evenly over entire across entire swale width. swale width. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. lnleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlel No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than ~-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-19 APPENDIX A MAl'HENANCE REQUIREMENTS ELOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 15 -FILTER STRIP Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and debris accumulated on the filter Filter strip site free of any trash or strip site. debris Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil. gasoline, concrete slurries or paint. according 10 applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass Strip Sediment Sediment accumulation on grass exceeds 2 No sediment deposits in treatment accumulation inches depth. area. Erosion/scouring Eroded or scoured swale bottom due to No eroded or scoured areas in channelization or high flows. bioswale. Cause of erosion or scour addressed. Grass too tall Grass excessively tall (greater than 1 O inches), Grass is between 3 and 4 inches tall, grass is thin or nuisance weeds and other thick and healthy. No clippings left vegetation has taken over. in swale. No nuisance vegetation present. Vegetation ineffective Grass has died out, become excessively tall Grass is healthy, less than 9 inches (greater than 10 inches) or nuisance vegetation is high and no nuisance vegetation taking over. present. Flow Spreader Concentrated flow Flow from spreader not uniformly distributed Flows are spread evenly over entire across entire swale width. swale width. lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. lnleUoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than Y2-inch at the joint of the No cracks more than X-inch wide at inleUoutlet pipes or any evidence of soil entering the joint of the inleUoutlet pipe. at the joints of the inleUoutlet pipes. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-20 APPENDIX A MAINTENANCE RE()lJIREMENTS FOR FLOW CONTROL, CONVEY Al\CE, AND WQ FACILITIES N0.16-WETPOND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Any trash and debris accumulated on the Wetpond site free of any trash or wetpond site. debris. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Side Slopes of Dam, Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and Berm, internal berm as a dam or berm, or any evidence of water dam or berm repaired. or Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of dams. berms or Trees do not hinder facility slopes, does not allow maintenance access, or performance or maintenance interferes with maintenance activity. If trees are activities. not a threat to dam, berm or embankment integrity, are not interfering with access or maintenance or leaves do not cause a plugging problem they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion conlrol measures. If erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Top or Side Slopes Settlement Any part of a dam, berm or embankment that has Top or side slope restored to design of Dam, Berm, settled 4 inches lower than the design elevation. dimensions. If settlement is internal berm or significant, a licensed civil engineer Embankment should be consulted to determine the cause of the settlement. Irregular surface on Top of berm not uniform and level. Top of berm graded to design internal berm elevalion. Pond Areas Sediment Accumulated sediment that exceeds 10% of the Sediment cleaned out to designed accumulation (except designed pond depth. pond shape and depth. first wetpool cell) Sediment Sediment accumulations in pond bottom that Sediment storage contains no accumulation (first exceeds the depth of sediment storage (1 foot) sediment. wetpool cell) plus 6 inches. Liner damaged (If Liner is visible or pond does not hold water as Liner repaired or replaced. Applicable) designed. Water level (first First cell empty, doesn't hold water. Water retained in first cell for most of wetpool cell) the year. Algae mats (first Algae mats develop over more than 10% of the Algae mats removed (usually in the wetpool cell) water surface should be removed. late summer before Fall rains, especially in Sensitive Lake Protection Areas.) Gravity Drain Inoperable valve Valve will not open and close. Valve opens and closes normally. Valve won't seal Valve does not seal completely. Valve completely seals closed. Emergency Overflow Tree growth Tree growth impedes flow or threatens stability of Trees removed. Spillway spillway. 2009 Surface Water Design Manual -Appendix A 1/912009 A-21 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CO~TROL. CONVEYANCE, AND WQ FACILITIES -~·~~------ N0.16-WETPOND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Pertormed Rock missing Only one layer of rock exists above native soi! in Spillway restored to design area five square feet or larger, or any exposure of standards. native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleUoutlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than !-'2-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-22 APPENDIX A MAINTf.NAl\CE REQUTREMENTS fOR fl.OW COJ\TROI, CONVEY ANCf., AND WQ f ACII.ITIES N0.17-WETVAULT Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Treatment Area Trash and debris Any trash and debris accumulated in vault No trash or debris in vault. (includes floatables and non-floatables). Sediment Sediment accumulation in vault bottom exceeds No sediment in vault. accumulation the depth of the sediment zone plus 6 inches. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vault Structure Damage to wall. Cracks wider than Y.i-inch, any evidence of soil Vault is sealed and structurally frame, bottom, and/or entering the structure through cracks, vault does sound. top slab not retain water or qualified inspection personnel determines that the vault is not structurally sound. Baffles damaged Baffles corroding, cracking, warping and/or Repair or replace baffles or walls to showing signs of failure or baffle cannot be specifications. removed. Ventilation Ventilation area blocked or plugged. No reduction of ventilation area exists. lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. lnleVoutlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inleVoutlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %:-inch at the joint of the No cracks more than X-inch wide at inleVoutlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inleUoutlet pipes. Gravity Drain Inoperable valve Valve will not open and close. Valve opens and closes normally. Valve won't seal Valve does not seal completely. Valve completely seals closed. Access Manhole Access cover/lid Access cover/lid cannot be easily opened by one Access cover/lid can be opened by damaged or difficult to person. Corrosion/deformation of cover/lid. one person. open Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper toots. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying BO lbs of lift. reinstalled by one maintenance person. Access doors/plate Large access doors not flat and/or access Doors close flat and covers access has gaps, doesn't opening not completely covered. opening completely. cover completely Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-23 APPE'lDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, ANIJ WQ FACILITIES NO, 18 -STORMWATER WETLAND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Side Slopes of Dam, Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and Berm, internal berm as a dam or berm, or any evidence of water dam or berm repaired. or Embankment piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of dams, berms or Trees do not hinder facility slopes, does not allow maintenance access, or performance or maintenance interferes with maintenance activity. If trees are activities. not a threat to dam, berm, or embankment integrity or not interfering with access or maintenance, they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. If erosion potential for continued erosion. My erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. Top or Side Slopes Settlement Any part of a dam, berm or embankment that has Top or side slope restored 10 design of Dam, Berm, settled 4 inches lower than the design elevalion. dimensions. lf settlement is internal berm or significant. a licensed civil engineer Embankment should be consulted to determine the cause of the settlement. Irregular surface on Top of berm not uniform and level. Top of berm graded flat to design internal berm elevation. Pond Areas Sediment Sediment accumulations in pond bottom that Sediment storage contains no accumulation (first exceeds the depth of sediment storage (1 foot) sediment. cell/forebay) plus 6 inches. Sediment Accumulated sediment thal exceeds 10% of the Sediment cleaned out to designed accumulation (wetland designed pond depth. pond shape and depth. cell) Liner damaged (If Liner is visible or pond does not hold water as Liner repaired or replaced. Applicable) designed. Water level (first Cell does not hold 3 feet of water year round. 3 feet of water retained year round. cell/forebay) Water level (wetland Cell does not retain water for at least 1 O months Water retained at least 1 O months of cell) of the year or wetland plants are not surviving. the year or wetland plants are surviving. Algae mats (first Algae mats develop over more than 10% of the Algae mats removed (usually ln the cell/forebay) water surface should be removed. late summer before Fall rains, especially in Sensitive Lake Protection Areas.) Vegetation Vegetation dead, dying, or overgrown (cattails) or Plants in wetland cell surviving and not meeting original planting specifications. not interfering with wetland function. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-24 APPENDIX A MAl~TENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEY AI\CL AND WQ FACILITIES NO. 18 -STORMWATER WETLAND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Gravity Drain Inoperable valve Valve will not open and close. Va!ve opens and closes normally. Valve won't seal Valve does not seal completely. Valve completely seals closed. Emergency Overflow Tree growth Tree growth impedes flow or threatens stability of Trees removed. Spillway spillway. Rock missing Only one layer of rock exists above native soil in Spillway restored to design area five square feet or larger, or any exposure of standards. native soil at the top of out flow path of spillway. Rip~rap on inside slopes need not be replaced. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. lnlet/oullet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than Yi-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-25 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, A'ID WQ FACILITIES -------------- NO, 19 -SAND FILTER POND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance Is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a (not in the treatment height. height no greater than 6 inches. area) Pre-Treatment (if Sediment Sediment accumulations in pond bottom that Sediment storage contains no applicable) accumulation exceeds the depth of sediment storage (1 foot) sediment. plus 6 inches. Liner damaged (If Liner is visible or pond does not hold water as Liner repaired or replaced. Applicable) designed. Water level Cell empty, doesn't hold water. Water retained in first cell for most of the year. Algae mats Algae mats develop over more than 10% of the Algae mats removed (usually in the water surface should be removed. late summer before Fall rains, especially in Sensitive Lake Protection Areas.) Pond Area Sediment Sediment or crust depth exceeds %-inch over 10 No sediment or crust deposit on accumulation % of surface area of sand filter. sand filter that would impede permeability of the filter section. Grass (if applicable) Grass becomes excessively tall (greater than 6 Mow vegetation and/or remove inches) or when nuisance weeds and other nuisance vegetation. vegetation start to take over or thatch build up occurs. Side Slopes of Pond Rodent holes Any evidence of rodent holes if facility is acting Rodents removed or destroyed and as a dam or berm, or any evidence of water dam or berm repaired. piping through dam or berm via rodent holes. Tree growth Tree growth threatens integrity of dams. berms or Trees do not hinder facility slopes, does not allow maintenance access, or performance or maintenance interferes with maintenance activity. If trees are activities. not a threat to dam, berm, or embankment integrity or not interfering with access or maintenance, they do not need to be removed. Erosion Eroded damage over 2 inches deep where cause Slopes stabilized using appropriate of damage is still present or where there is erosion control measures. ff erosion potential for continued erosion. Any erosion is occurring on compacted slope, a observed on a compacted slope. licensed civil engineer should be consulted to resolve source of erosion. 1/912009 2009 Surface Water Design Manual-Appendix A A-26 APPENDIX A 'vlAINTENA'JCE REQl/JREMENTS FOR FLOW CO'JTROL, CONVEY i\NCE, AND WQ Fi\CILII IES NO. 19 -SAND FILTER POND Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintena nee Is Performed Sand Filter Media Plugging Drawdown of water through the sand filter media, Sand filter media surface is aerated takes longer than 24 hours. and/or flow through and drawdown rate is normal. lhe overilow pipes occurs frequently. A sieve analysis of >4% -100 or >2% -200 requires replacing sand filter media. Prolonged flows Sand is saturated for prolonged periods of time Excess flows bypassed or confined (several weeks) and does not dry out between to small portion of filter media storms due to continuous base flow or prolonged surface. flows from detention facilities. Short circuiting Flows become concentrated over one section of Flow and percolation of water the sand filter rather than dispersed or drawdown through the sand filter is uniform and rate of pool exceeds 12 inches per hour. dispersed across the entire filter area and drawdown rate is normal. Media thickness Sand thickness is less than 6 inches. Rebuild sand thickness to a minimum of 6 inches and preferably to 18 inches. Underdrains and Sediment/debris Underdrains or clean-outs partially plugged or Underdrains and clean-outs free of Clean-Outs filled with sediment and/or debris. Junction sediment and debris and are box/cleanout wyes not watertight. watertight. lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatabtes and non-floatabtes). Damaged Cracks wider than Yz-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. Rock Pad Missing or out of Only one layer of rock exists above native soil in Rock pad restored to design place area five square feet or larger, or any exposure of standards. native soil. Flow spreader Concentrated flow Flow from spreader not uniformly distributed Flows spread evenly over sand filter. across sand filter. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-27 APPPNllIX A MATNTPNANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, ANlJ WQ FACILITIES NO. 20 -SAND FILTER VAULT Maintenance Defect or Problem Condition When Maintenance is Needed Resu Its Expected When Component Maintenance is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard 10 County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Grass/groundcover Grass or groundcover exceeds 18 inches in Grass or groundcover mowed to a height. height no greater than 6 inches. Pre-Treatment Sediment Sediment accumulation exceeds the depth of the Sediment storage contains no Chamber accumulation sediment zone plus 6 inches. sediment. Sand Filter Media Sediment Sediment depth exceeds %-inch on sand filter Sand filter freely drains at normal accumulation media. rate. Trash and debris Trash and debris accumulated in vault (floatables No trash or debris in vault. and non-floalables). Plugging Orawdown of water through the sand filter media, Sand filter media drawdown rate is takes longer than 24 hours, and/or flow through normal. the overflow pipes occurs frequently. A sieve analysis of >4% -100 or >2% -200 requires replacing sand filter media. Short circuiting Seepage or flow occurs along the vault walls and Sand filter media section re-laid and corners. Sand eroding near inflow area. compacted along perimeter of vault Cleanout wyes are not watertight. to form a semi-seal. Erosion protection added to dissipate force of incoming flow and curtail erosion. Vault Structure Damaged to walls, Cracks wider than %-inch, any evidence of soil Vault replaced or repaired to provide frame, bottom and/or entering the structure through cracks or qualified complete sealing of the structure. top slab. inspection personnel determines that the vault is not structurally sound. Ventilation Ventilation area blocked or plugged. No reduction of ventilation area exists. Underdrains and Sediment/debris Underdrains or clean-outs partially plugged, filled Underdrains and clean-outs free of Cleanouts with sediment and/or debris or not watertight. sediment and debris and sealed. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-28 APPENDTX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL. COI\VEYAI\CE. AND WQ FACILITIES .. ··--- NO. 20 -SAND FILTER VAULT Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Pertormed Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and covers access completely opening not completely covered. opening completely. Lifting Rings missing. Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-29 Al'l'ENl)IX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, ANIJ WQ FACILITIFS NO. 21 -STORM FILTER (CARTRIDGE TYPE) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Site Trash and debris Any trash or debris which impairs the function of Trash and debris removed from the facility. facility. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oils, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Life cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed. Vault Treatment Sediment on vault Greater than 2 inches of sediment. Vault is free of sediment. Area floor Sediment on top of Greater than % inch of sediment. Vault is free of sediment. cartridges Multiple scum lines Thick or multiple scum lines above top of Cause of plugging corrected, above top of cartridges. Probably due to plugged canisters or canisters replaced if necessary. cartridges underdrain manifold. Vault Structure Damage to wall, Cracks wider than X-inch and any evidence of Vault replaced or repaired to design Frame, Bottom, and/or soil particles entering the structure through the specifications. Top Slab cracks, or qualified inspection personnel determines the vault is not structurally sound. Baffles damaged Baffles corroding, cracking warping, and/or Repair or replace baffles to showing signs of failure as determined by specification. maintenance/inspection person. Filter Media Standing water in 9 inches or greater of static water in the vault for No standing water in vault 24 hours vault more than 24 hours following a rain event and/or after a rain event. overflow occurs frequently. Probably due to plugged filter media, underdrain or outlet pipe. Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and Sediment/debris Underdrains or clean-outs partially plugged or Underdrains and clean-outs free of Clean-Outs filled with sediment and/or debris. sediment and debris. fnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes ftoatables and non-floatables). Damaged Cracks wider than X-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. al the joints of the inlet/outlet pipes. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignmenl, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-30 APPENDIX A MAINTEI\ANCE RFQl/lRE.MENTS EOR El.OW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 21 -STORM FILTER (CARTRIDGE TYPE) Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and cover access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings no! capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-3\ APPENDIX A MAll\TENi\NCE REQUIREMENTS FLOW CONTROL, CONVEYA'JCE, AND WQ FACILITIES ~~-- NO. 22-BAFFLE OIUWATER SEPARATOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Petformed Site Trash and debris Any trash or debris which impairs the function of Trash and debris removed from the facility. facility. Contaminants and Floating oil in excess of 1 inch in first chamber, No contaminants present other than pollution any oil in other chambers or other contaminants a surface oil film. of any type in any chamber. Vault Treatment Sediment Sediment accumulates exceeds 6 inches in the No sediment in the vault. Area accumulation vault. Discharge water not Inspection of discharge water shows obvious Effluent discharge is clear. clear signs of poor water quality-effluent discharge from vault shows thick visible sheen. Trash or debris Any trash and debris accumulation in vault Vault is clear of trash and debris. accumulation (floatables and non-floatables). Oil accumulation Oil accumulations that exceed 1 inch, at the No visible oil depth on water. surface of the water in the oil/water separator chamber. Vault Structure Damage to Wall, Cracks wider than %-inch or evidence of soil Vault replaced or repaired to design Frame, Bottom, and/or particles entering the structure through the specifications. Top Slab cracks, or maintenance/inspection personnel determines that the vault is not structurally sound. Baffles damaged Baffles corroding, cracking, warping and/or Repair or replace baffles to showing signs of failure as determined by specifications. maintenance inspection personnel. Gravity Drain Inoperable valve Valve will not open and close. Valve opens and closes normally. Valve won't seal Valve does not seal completely. Valve completely seals closed. lnleUOutlet Pipe Sediment Sediment filling 20% or more of the pipe. lnlet/outlel pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatabfes). Damaged Cracks wider than %-inch at the joint of the No cracks more than X-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at lhe joints of the inlet/outlet pipes. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires Immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and cover access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or cover/lid. remove cover/lid. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-32 APPENDIX A '.v!ATNTENA"ICE RFQUIRFMFNTS FOR FI.OW CO'JTROI., CONVEYANCE, AO:D WQ FACILITIF.S ---- NO. 23 -COALESCING PLATE OIL/WATER SEPARATOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed ----- Site Trash and debris Any trash or debris which impairs lhe function of Trash and debris removed from the facility. facility. Contaminants and Floating oil in excess of 1 inch in first chamber. No contaminants present other than pollution any oil in other chambers or other contaminants a surface oil film. of any type in any chamber. Vault Treatment Sediment Sediment accumulation of 6 inches or greater in No sediment in the forebay. Area accumulation in the the forebay. forebay Discharge water not Inspection of discharge waler shows obvious Repair function of plates so effluent clear signs of poor water quality -effluent discharge is clear. from vault shows thick visible sheen. Trash or debris Trash and debris accumulation in vault Trash and debris removed from accumulation (floatables and non-floatables). vault. Oil accumulation Oil accumulation that exceeds 1 inch al lhe water No visible oil depth on water and surface in the in the coalescing plate chamber. coalescing plates clear of oil. Coalescing Plates Damaged Plate media broken, deformed, cracked and/or Replace that portion of media pack showing signs of failure. or entire plate pack depending on severity of failure. Sediment Any sediment accumulation which interferes with No sediment accumulation accumulation the operation of the coalescing plates. interfering with the coalescing plates. Vault Structure Damage to Wall, Cracks wider than %-inch and any evidence of Vault replaced or repaired to design Frame, Bottom, and/or soil particles entering the structure through the specifications. Top Slab cracks, or maintenance inspection personnel determines that the vault is not structurally sound. Baffles damaged Baffles corroding, cracking, warping and/or Repair or replace baffles to showing signs of failure as determined by specifications. mainlenance/i nspection person. Ventilation Pipes Plugged Any obstruction to lhe ventilation pipes. Ventilation pipes are clear. Shutoff Valve Damaged or Shutoff valve cannot be opened or closed. Shutoff valve operates normally. inoperable Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than 1h-inch at the joint of the No cracks more than "Xi-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Manhole access covered. Any open manhole requires immediate maintenance. Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. not working maintenance person with proper lools. Bolts cannot be seated. Self-locking cover/lid does not work. Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and remove cover/lid after applying 80 lbs of lift. reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-33 APPENDIX A MAINTENANCE REQUIREMEKTS FLOW CONTROL, CONVEYANCE, AKD WQ f ACILITIES NO. 23 -COALESCING PLATE OIUWATER SEPARATOR Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Large access Damaged or difficult Large access doors or plates cannot be Replace or repair access door so it doors/plate to open opened/removed using normal equipment. can opened as designed. Gaps, doesn't cover Large access doors not flat and/or access Doors close flat and cover access completely opening not completely covered. opening completely. Lifting Rings missing, Lifting rings not capable of lifting weight of door Lifting rings sufficient to lift or rusted or plate. remove door or plate. 1/9/2009 2009 Surface Water Design Manual-Appendix A A-34 APPENDIX A YIAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 24-CATCH BASIN INSERT Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Media Insert Visible Oll Visible oil sheen passing through media Media inset replaced. Insert does not fit Flow gets into catch basin without going through All flow goes through media. catch basin properly media. Filter media plugged Filter media plugged. Flow through filter media is normal. Oil absorbent media Media oil saturated. Oil absorbent media replaced. saturated Water saturated Catch basin insert is saturated with water, which Insert replaced. no longer has the capacity to absorb. Service life exceeded Regular interval replacement due to typical Media replaced at manufacturer's average life of media insert product, typically one recommended interval. month. Seasonal 1/Vhen storms occur and during the wet season. Remove, clean and replace or Install maintenance new insert after major storms. monthly during the wet season or at manufacturer's recommended interval. 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-35