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HomeMy WebLinkAboutRS_Drainage_Report_181221_v1 Prepared for: Segale Properties LLC PO Box 88028 Tukwila, WA 98138 Prepared by: CPH Consultants Jamie Schroeder, PE Casey Torres, EIT 11431 Willows RD NE, Suite 120 Redmond, WA 98052 December 21, 2018 Technical Information Report Upper Balch Pit – Grade and Fill Permit CPH Project No. 0061-18-002 Renton, WA CP H CO N SU LTA NT S Prepared for: Segale Properties LLC PO Box 88028 Tukwila, WA 98138 Prepared by: CPH Consultants Jamie Schroeder, PE Casey Torres, EIT 11431 Willows RD NE, Suite 120 Redmond, WA 98052 December 21, 2018 Technical Information Report Upper Balch Pit – Grade and Fill Permit CPH Project No. 0061-18-002 Renton, WA CP H CO N SU LTA NT S 11431 WILLOWS ROAD NE, SUITE 120 REDMOND, WA 98052 P: (425) 285-2390 | F: (425) 285-2389 www.cphconsultants.com Site Planning Civil Engineering Project Management Land Use Consulting UPPER BALCH PIT GRADE AND FILL PERMIT RENTON, WASHINGTON TECHNICAL INFORMATION REPORT December 21, 2018 Prepared For: Segale Properties LLC PO Box 88028 Tukwila, WA 98138 Prepared By: CPH Consultants Jamie Schroeder, PE Casey Torres, EIT CPH Project No. 0061-18-002 Site Planning Civil Engineering Project Management Land Use Consulting TECHNICAL INFORMATION REPORT UPPER BALCH PIT GRADE AND FILL PERMIT CITY OF RENTON, WA TABLE OF CONTENTS SECTION 1 – PROJECT OVERVIEW 3 FIGURE 1 – VICINITY MAP FIGURE 2 – TIR WORKSHEET SECTION 2 – CONDITIONS AND REQUIREMENTS SUMMARY 9 SECTION 3 – OFFSITE ANALYSIS 11 SECTION 4 – FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 13 SECTION 5 – CONVEYANCE SYSTEM ANALYSIS AND DESIGN 16 SECTION 6 – SPECIAL REPORTS AND STUDIES 17 SECTION 7 – OTHER PERMITS 18 SECTION 8 – CSWPP PLAN ANALYSIS AND DESIGN 19 SECTION 9 – BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 21 SECTION 10 – OPERATIONS AND MAINTENANCE MANUAL 22 FIGURES FIGURE 3 – EXISTING SITE CONDITIONS FIGURE 4 – DEVELOPED SITE CONDITIONS APPENDICES APPENDIX A – NRCS SOILS DATA AND GEOTECHNICAL ENGINEERING EVALUATION REPORT APPENDIX B – WWHM REPORT APPENDIX C – OTHER REPORTS APPENDIX D – OPERATIONS AND MAINTENANCE MANUAL Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 3 SECTION 1 – PROJECT OVERVIEW This Technical Information Report (TIR) is provided to describe the stormwater conditions and proposed drainage improvements for the Upper Balch Pit – Grade and Fill permit project. The project proposes to grade and fill an existing property within the City of Renton to prepare the site for future residential development. This report is provided to identify the applicable storm drainage standards and to summarize the analyses and design provisions proposed for the project to comply with city surface water standards. The information provided within this TIR represents the basis of design for the storm drainage systems and surface water conditions for the project. The vicinity map provided below as Figure 1 illustrates the general location of the property. The street address of the project site is 301 Monroe Ave NE (King County tax parcel no. 1623059059). More generally, the site is located in the NE ¼ of the NW ¼ of Section 16 of Township 23 North, Range 5 East, in King County, Washington (see Vicinity Map below). Figure 1– Location/Vicinity Map Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 4 The project site is comprised of one undeveloped parcel with an area of approximately 14.4 acres. The project site has been used as an upland fill and reclamation site since 1982. It was used as a permitted sand/gravel pit from 1962 to 1982 under the name, “Upper Balch Pit.” The property currently has a valid Grade and Fill permit (#LUA10-056) which allows the pit to be filled to an elevation of 325 feet. In addition, the City of Renton currently discharges stormwater to the site through a Temporary Storm Drainage Easement (AF# 2007092800176), where the runoff infiltrates on-site. The easement will terminate once the pit is filled to an elevation of 325 feet. At or before this time, it is expected the storm pipes will be removed. Steep slopes are present around the perimeter of the property which will be eliminated as the pit is filled. A number of trees of varying type, age, and health condition exist on the site and there is a chain-link fence around the perimeter of the property. Figure 3 displays the existing site conditions. The project proposes the continue filling the pit to support an anticipated residential development. Final grades will be at or near the existing grades of the surrounding streets and land area. Proposed finished grades will generally convey surface flows to the northwest. The project is exempt from Water Quality treatment and Flow Control per current City of Renton surface water standards. However, a wetpond and infiltration trench are proposed in the northwest portion of the site to support the anticipated future development. These facilities have been preliminarily sized based on a conceptual residential development site plan. The infiltration trench has been sized to fully infiltrate all stormwater runoff. These facilities will also serve runoff from this project. No off-site discharge is proposed. The proposed grading and drainage plan is shown in Figure 4. Storm drainage controls for this project are proposed in accordance with the 2017 City of Renton Surface Water Design Manual (RSWDM), which is based on the 2016 King County Surface Water Design Manual (KCSWDM) with some modifications to reflect City of Renton specific requirements. On-site Soil Conditions The soils of the area are characterized generally by the Natural Resource Conservation Services (NCRS) as Arents, Everett Material (An). The NRCS also correctly identifies the majority of the site as a pit. A site- specific investigation of the existing site geotechnical conditions was performed by Terra Associates, Inc. A copy of the NRCS soils data and the full geotechnical report is provided in Appendix A of this report. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 5 Figure 2 – Technical Information Report (TIR) Worksheet, 2017 Surface Water Design Manual Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner: Segale Properties, LLC Project Name: Upper Balch Pit Phone: (206) 575-2000 DDES Permit #: ______________________ Address: P.O. Box 88028 Tukwila, WA 98138 Location: Township: 23 N Range: 5 E Project Engineer: Jamie Schroeder, PE Section: 16 Phone: (425) 285-2392 Site Address: 301 Monroe Ave NE Renton, WA 98056 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Landuse Services  DFW HPA  Shoreline Subdivision / Short Subd. / UPD  COE 404 Management  Building Services  DOE Dam Safety  Structural M/F / Commercial / SFR  FEMA Floodplain Rockery/Vault/ ____ ◼ Clearing and Grading  COE Wetlands  ESA Section 7  Right-of-Way Use  Other:  Other: Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Full / Targeted / Type (circle one): Full / Modified / Review (circle): Large Site Small Site Date (include revision Date (include revision dates): 12/21/18 dates): 12/21/18 Date of Final: Date of Final: Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) Date of Approval: _____________________________ Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 6 Figure 2 – Technical Information Report (TIR) Worksheet, 2017 Surface Water Design Manual (cont’d.) Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Describe: Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: Highlands Special District Overlays: Drainage Basin: Lower Cedar River Stormwater Requirements: Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ◼ Steep Slope To be removed with fill  Lake  Erosion Hazard  Wetlands  Landslide Hazard  Closed Depression  Coal Mine Hazard  Floodplain  Seismic Hazard  Other  Habitat Protection Part 10 SOILS Soil Type Slopes Erosion Potential An 0% - 50%+ Yes  High Groundwater Table (within 5 feet)  Sole Source Aquifer  Other __________________  Seeps/Springs  Additional Sheets Attached Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 7 Figure 2 – Technical Information Report (TIR) Worksheet, 2017 Surface Water Design Manual (cont’d.) Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION / SITE CONSTRAINT  Core 2 – Offsite Analysis  Sensitive/Critical Areas  SEPA  Other   Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) On-site infiltration at low point of site Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: 1 Offsite Analysis Level: 1 / 2 / 3 Dated: 12/21/18 Flow Control Level: 1 / 2 / 3 or Exemption Number: Basic Exemption (include a facility summary sheet) Small Site BMP’s: _N/A_____________________ Conveyance System Spill containment located at: Erosion and Sediment Control ESC Site Supervisor: TBD Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality Type: Basic / Sens. Lake / Enhanced Basic / Bog (include facility summary sheet) or Exemption No. Surface Area Exemption Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Type: CDA / SDO / MDP / BP / LMP / Shared Fac / None Requirements Name: ________________________________ Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: N/A Flood Protection Facilities Description: Source Control Describe land use: None (comm./industrial landuse) Describe any structural controls: None Oil Control High-use Site: Yes / No Treatment BMP: __________________________________ Maintenance Agreement: Yes / No with whom?: Other Drainage Structures Describe: Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 9 SECTION 2 – CONDITIONS AND REQUIREMENTS SUMMARY Compliance with Project Drainage Requirements The storm drainage and temporary erosion control standards for the project are established by the 2017 City of Renton Surface Water Design Manual (RSWDM). The RSWDM specifies nine core and six special requirements that are to be met for this project. Compliance and/or applicability of each of these design standards are summarized below: RSWDM Core Requirements 1. Discharge at Natural Location: Stormwater runoff from the site currently flows to the bottom of the pit where it then infiltrates. No runoff discharges off-site. On-site stormwater will maintain this existing drainage pattern by fully infiltrating on-site in accordance with current flow control standards. 2. Offsite Analysis: Summarized in Section 3 – Off-site Analysis. 3. Flow Control: The project qualifies for the Basic Exemption. This is further described in Section 4 – Flow Control and Water Quality Facility Analysis and Design. 4. Conveyance System: The project proposes to collect on-site runoff and convey it to an on-site wetpond followed by an infiltration trench in the northwest portion of the site. These improvements are shown in Figures 4 and 5 and are described further in Section 5 – Conveyance System Analysis and Design. 5. Construction Stormwater Pollution Prevention: Temporary controls are as described in Section 8 – CSWPPP Analysis and Design. 6. Maintenance and Operations: The on-site storm drainage facilities are proposed to be privately maintained. Refer to Appendix D for Maintenance Requirements. 7. Financial Guarantees and Liability: All required bonds and liability insurance will be provided prior to final approval. 8. Water Quality: The project qualifies for the Surface Area Exemption. This is further described in Section 4 – Flow Control and Water Quality Facility Analysis and Design. 9. On-site BMPs: This project proposes no development and therefore BMPs are not applicable. RSWDM Special Requirements 1. Other Adopted Area-Specific Requirements: No area-specific requirements apply to this project site. 2. Flood Hazard Area Delineation: The limits of this project are not located within or in proximity to a 100-year floodplain. 3. Flood Protection Facilities: Not applicable. 4. Source Control: No additional source control is proposed. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 10 5. Oil Control: The project is not considered a high-use area and no special oil control provisions are required. 6. Aquifer Protection Area: The project is not believed to be in an Aquifer Protection Area per discussions with the City. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 11 SECTION 3 – OFF-SITE ANALYSIS Task 1: Study Area Definition and Maps The proposed project site is located at 301 Monroe Ave NE in Renton, WA. The site is currently undeveloped and operates as a fill and reclamation site. It was previously used as a quarry pit for sand and gravel. A partially-paved access road leads from an entrance gate along the western property boundary to the southern portion of the pit. The south and east slopes of the property are heavily vegetated while the west and north slopes have moderate vegetation. The existing site topography consists of slopes ranging from 0% to 50%. The property is bordered by the Renton Transfer Station and King County Department of Transportation to the south, Greenwood Memorial Park to the east, and retail buildings to the north. Power lines run through the northeast portion of the site in a 150’ wide Puget Sound Energy Easement (AF #3425304 and #2571770). The existing site conditions are shown in Figure 3. Task 2: Resource Review King County (KC) iMAP, City of Renton (COR) Maps, and GIS Data were reviewed to identify any potential sensitive areas in the proximity of the project site. • Wetlands: COR Maps identifies a possible wetland on the project site. However, a wetland reconnaissance of the property performed by Raedeke Associates, Inc. concluded that the property contains no areas that exhibit wetland characteristics. • Streams and 100-year Floodplain: The project site is not located in the 100-year floodplain. • Erosion Hazard Areas: COR Maps identifies no erosion hazard areas on the project site. • Seismic Hazard Areas: COR Maps identifies no seismic hazard areas on the project site. • Coal Mine Hazard Areas: COR Maps identifies no coal mine hazard areas on the project site. • Critical Aquifer Recharge Area: The project site is not located within a critical aquifer recharge area per KC iMAP King County iMAP and COR Maps were also reviewed for downstream drainage complaints. The parcel to the northwest of the site (Renton Public Health Center) has had two drainage complaints. However, the project site neither discharges to or receives runoff from this parcel. Thus, the complaints do not appear to be relevant. Task 3: Field Inspection A field inspection was performed on December 21, 2018. The existing topography of the site has slopes ranging from 0% to 50%. The project site is comprised of a single drainage basin with surface runoff traveling primarily as sheet flow over pervious areas. The drainage basin is comprised mostly of disturbed soil and patches of grass and treed areas. Based on visual inspection during the site visit and survey contour data, there are three (3) low points where runoff collects and infiltrates on-site. Task 4: Drainage System Description Downstream Basin Stormwater runoff from the site flows to the bottom of the pit where it then infiltrates. No runoff discharges off-site. Thus, the project site does not have a downstream basin. Upstream Basin The project site is fronted by Monroe Ave NE to the east, NE 2nd St to the south, and Jefferson Ave NE to the west. Monroe Ave NE and NE 2nd St contain vertical curb and gutter which prevents any upstream runoff from discharging on-site. Jefferson Ave NE is a crowned roadway without curb. Runoff from portions of the eastside of this road appears to flow on-site and infiltrate. The parcels to the north of the project Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 12 site are at lower elevations and thus no upstream runoff from the north is expected. The project site contains a temporary easement (AF# 2007092800176) to the City of Renton for a surface water drainage overflow system in Monroe Ave NE. The easement will terminate once the pit is filled to an elevation of 325 feet. At or before this time, it is expected the storm pipes will be removed. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 13 SECTION 4 – FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN The hydrologic analysis of the runoff conditions for this project is based on drainage characteristics such as basin area, soil type, and land use (i.e., pervious vs. impervious) in accordance with the King County Surface Water Design Manual and City of Renton addendum. The Western Washington Hydraulic Model (WWHM) software was used to evaluate the stormwater runoff conditions for the project site and to design the on-site flow control facilities. The following is a summary of the results of the analysis and the proposed drainage facility improvements for this project. Existing Site Hydrology The existing site conditions are shown in Figure 3 and summarized in Table 4.1 below. Table 4.1 – Land Use Cover, Existing Site Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 14.43 0.50 0.00 13.93 The Western Washington Hydraulic Model (WWHM) software was used to model the existing site hydrology and calculate runoff peak rates. The results of the existing site runoff analysis are provided in Appendix B. Existing site conditions were modeled as historic site (i.e., fully forested) conditions in the analysis of the pre-developed conditions for all on-site targeted developed surfaces in accordance with RSWDM standards for Flow Control. The pre-developed land use conditions used in the WWHM model are summarized in Table 4.2. Table 4.2 – Land Use Cover, Pre-Developed Site Conditions (for WWHM) Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 14.43 0 14.43 0 Developed Site Hydrology The site is planned to continue filling the pit to support an anticipated residential development. Final grades will be at or near the existing grades of the surrounding streets and land area. The site will be hydroseeded upon completion of grading and filling activities. The developed site conditions contributing to the proposed flow control and water quality facilities were modelled as a single basin using the WWHM software program. An analysis was also performed for a future conceptual residential development. These values for the developed land use condition and future residential developed land use condition in the WWHM analyses are summarized in Tables 4.3a and 4.3b. Appendix B contains the WWHM model results. Table 4.3a – Land Use Cover, Developed Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 14.43 0.00 0.00 14.43 Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 14 Table 4.3b – Land Use Cover, Future Residential Developed Conditions Basin ID Total Area (AC) Land Cover (AC) Impervious Till Forest Till Grass Site Basin 14.43 7.09 0.00 7.34 Flow Control The project qualifies for the Basic Exemption from flow control facilities per Section 1.2.3 of the RSWDM since less than 5,000 square feet of new plus replaced impervious surface will be created and less than ¾ acres of new pervious surface will be added. No new or replaced impervious surface or new pervious surface is proposed with this project. The project does, however, propose to construct flow control facilities which are sized to support an anticipated future residential development. Future development on the site will be subject to the Flow Control Duration Standard (Forested Conditions). The on-site infiltration trench has been sized to infiltrate 100% of runoff from a conceptual residential site plan. The infiltration trench will also infiltrate 100% of runoff from this project. Table 4.4 shows the pre-developed and post-developed peak flows for the 2-year, 10-year, 50-year, and 100-year storm events. Table 4.5 summarizes the design criteria for the proposed infiltration trench. Table 4.4 – Peak Flow Summary Facility Land-Use Condition Peak Flow Rates at Point of Compliance (cfs) 2-year 10-year 50-year 100-year Infiltration Trench Pre-Developed 0.424 0.803 1.039 1.115 Developed 0.000 0.000 0.000 0.000 Future Residential Developed 0.000 0.000 0.000 0.000 Table 4.5 – Infiltration Facility Summary Infiltration Trench Information Length 650 ft Width 10 ft Depth 8 ft Gravel Porosity 0.40 Detention Volume (Live) 20,800 cf Water Quality Design The project qualifies for the Surface Area Exemption from water quality facilities per Section 1.2.8 of the RSWDM since less than 5,000 square feet of new plus replaced PGIS that is not fully dispersed will be created, and less than ¾ acre of new PGPS that is not fully dispersed will be added. No PGIS or PGPS is proposed with this project. The project does, however, propose to construct water quality facilities which are sized to support an anticipated future residential development. Future development on the site will be subject to Basic Water Quality standards. The on-site wetpond has been sized based on a conceptual residential site plan. The water quality pond was designed in general accordance with Section 6.4.1.2 of the RSWDM. Table 4.6 summarizes the design conditions of the wet pond facility. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 15 Table 4.6 – Water Quality Pond Design Wet Pond Information W/Q Volume Required 45,989 cf W/Q Volume Provided 60,690 cf Cell 1 Depth 6 ft Cell 2 Depth 6 ft WQ elevation 328.0 The pond has 3H:1V side slopes and is divided into two cells separated by a berm with 3:1 side slopes. The top of the berm is one foot below the water quality design water surface and the flow path from inlet to outlet has a greater than 3:1 ratio as suggested by RSWDM. The first cell includes 1 foot of sediment storage and contains approximately 35% of the total water quality volume. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 16 SECTION 5 – CONVEYANCE SYSTEM ANALYSIS AND DESIGN Surface water collection and conveyance for the project is proposed by means of grading. Stormwater runoff will generally sheet flow northwesterly across the site. Drainage swales constructed along the northern and western boundaries of the site will capture and convey runoff to the on-site wetpond. The conceptual storm drainage conveyance systems are illustrated in Figure 4. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 17 SECTION 6 – SPECIAL REPORTS AND STUDIES Geotechnical Engineering Evaluation Report, by Terra Associates, Inc., November 9, 2018 Geologic and Sensitive Areas Report, by GeoEngineers, August 2, 2010 Wetland Reconnaissance Memo, by Raedeke Associates, Inc., July 30, 2010 Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 18 SECTION 7 – OTHER PERMITS A Grade and Fill Permit and SEPA review from the City of Renton is the only permit expected to be necessary for the project. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 19 SECTION 8 – CSWPPP ANALYSIS AND DESIGN Site specific details and provisions for the temporary erosion and sediment control (ESC) facilities are provided with the improvement plans that accompany this TIR. The proposed facilities have been selected and sized in accordance with the recommendations provided in the RSWDM standards. In addition to the site-specific ESC measures, the following general Best Management Practices (BMPs) for sediment control shall also be implemented in accordance with the provisions of the RSWDM: 1. Clearing Limits Construction clearing limits fence or silt fence will be installed by the contractor along the entire project corridor to prevent disturbance of project areas not designated for construction. These fences will be installed prior to clearing and grading activities where appropriate. 2. Cover Measures Temporary and permanent cover measures will be provided by the contractor to protect disturbed areas. Disturbed areas will be seeded and mulched to provide permanent cover measure and to reduce erosion within seven days, if those areas not scheduled for immediate work. 3. Perimeter Protection The contractor will install silt fences as indicated on the drawings prior to any up slope clearing, grading and trenching activities in order to reduce the transport of sediment offsite. 4. Traffic Area Stabilization Stabilized pads of quarry spalls will be installed by the contractor at all egress points from the project site as required to reduce the amount of sediment transported onto paved roads or other offsite areas by motor vehicles. 5. Sediment Retention Sediment retention will be provided by silt fencing, catch basin inlet protection, and a temporary sediment pond during construction at the locations and dimensions shown on the project drawings. 6. Surface Water Control Surface water control will include interceptor ditches, temporary culverts, a sediment pond, check dams, and/or other inlet and outlet protection at the locations and dimensions shown on the drawings. 7. Dust Control Water and/or street sweeping equipment will be used by the contractor to control dust emissions during construction operations. 8. Wet Season Requirements If soils are exposed during the period of October 1 to April 30, the contractor will mulch and seed or otherwise cover as much disturbed area as possible by the first week of October, in order to provide protective ground cover for the wet season. The contractor will also conform to the following wet season special provisions: A. Apply cover measures to disturbed areas that are to remain unworked for more than two days. B. Protect stockpiles that are to remain unworked for more than 12 hours. No area is to be left uncovered/denuded longer than 12 hours during the winter months. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 20 C. Provide onsite stockpiles of cover materials sufficient to cover all disturbed areas. D. Seed all areas that are to be unworked during the wet season by the end of the first week of October. E. Apply mulch to all seeded areas for protection. F. Provide onsite storage of 50 linear feet of silt fence (and the necessary stakes) for every acre of disturbed area. Straw bales are to be stockpiled onsite for use in an emergency. G. Provide construction road and parking lot stabilization areas for all sites. H. Provide additional sediment retention as required by the City of Renton Engineer. I. Provide additional surface water controls as required by the City of Renton Engineer. J. Implement construction phasing and more conservative BMPs for construction activity near surface waters (to be evaluated). K. Review and maintain TESC measures on a weekly basis and within 24-hours after any runoff-producing event. 9. Sensitive Areas Restrictions No sensitive areas are located on-site. 10. Maintenance Requirements All ESC measures will be maintained and reviewed on a regular basis following the standard maintenance requirements identified in the project drawings. An ESC supervisor will be designated by the contractor and the name, address and phone number of the ESC supervisor will be given to the City prior to the start of construction. A sign will be posted at the primary entrance to the project site identifying the ESC supervisor and his/her phone number. The ESC supervisor will inspect the site at least once a month during the dry season, weekly during the wet season, and within 24 hours of each runoff-producing storm. A standard ESC maintenance report will be used as a written record of all maintenance. The contractor will be responsible for phasing of erosion and sediment controls during construction so that they are coordinated with construction activities. The contractor will also be responsible for maintenance of temporary controls during construction, including removal of accumulated sediment, and for the removal of the controls and remaining accumulated sediment at the completion of construction. 11. Final Stabilization Prior to obtaining final construction approval, the site shall be stabilized, the structural ESC measures removed and drainage facilities cleaned. To obtain final construction approval, the following conditions must be met: • All disturbed areas of the site should be vegetated or otherwise permanently stabilized in accordance with project BMPs. At a minimum, disturbed areas should be seeded and mulched to provide a high likelihood that sufficient cover will develop shortly after final approval. The plans include erosion control notes and specifications for hydro-seeding and mulching disturbed areas. • Structural measures such as silt fences, pipe slope drains, storm drain inlet protection and sediment traps and ponds shall be removed once the proposed improvements are complete and vegetated areas are stabilized. All permanent surface water facilities shall be cleaned completely and restored to working order prior to removal of ESC facilities. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 21 SECTION 9 – BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT All required bonds, facility summaries, and covenants will be provided prior to final approval. Upper Balch Pit – Grade and Fill Permit Technical Information Report CPH Project No. 0061-18-002 December 21, 2018 CP|H CONSULTANTS Page 22 SECTION 10 – OPERATIONS AND MAINTENANCE MANUAL The on-site storm drainage facilities for this project will be privately maintained. An Operations and Maintenance Manual is included as Appendix D. Site Planning Civil Engineering Project Management Land Development Consulting FIGURES MONROE AVENUE NORTHEAST (PUBLIC) JEFFERSON AVENUE NORTHEAST (PRIVATE)NORTHEAST 2ND STREET(PRIVATE)IN FEETPLAN 0 N 50 100 FIGURE 3 - EXISTING SITE CONDITIONS CP H O N S U L T A N T S 11431 Willows Rd. NE, Suite 120 Redmond, WA 98052 Phone: (425) 285-2390 | FAX: (425) 285-2389 www.cphconsultants.com Site Planning • Civil Engineering Land Use Consulting • Project Management MONROE AVENUE NORTHEAST (PUBLIC) JEFFERSON AVENUE NORTHEAST (PRIVATE)NORTHEAST 2ND STREET(PRIVATE)LEGEND IN FEETPLAN 0 N 50 100 FIGURE 4 - DEVELOPED SITE CONDITIONS CP H O N S U L T A N T S 11431 Willows Rd. NE, Suite 120 Redmond, WA 98052 Phone: (425) 285-2390 | FAX: (425) 285-2389 www.cphconsultants.com Site Planning • Civil Engineering Land Use Consulting • Project Management Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX A NRCS SOILS DATA AND GEOTECHNICAL ENGINEERING EVALUATION REPORT Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/19/2018 Page 1 of 35259360525940052594405259480525952052595605259600525964052596805259360525940052594405259480525952052595605259600525964052596805259720561930561970562010562050562090562130562170 561930 561970 562010 562050 562090 562130 562170 47° 29' 16'' N 122° 10' 41'' W47° 29' 16'' N122° 10' 28'' W47° 29' 4'' N 122° 10' 41'' W47° 29' 4'' N 122° 10' 28'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:1,780 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 14, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 8, 2014—Jul 15, 2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/19/2018 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI An Arents, Everett material 4.2 28.7% PITS Pits 10.3 71.3% Totals for Area of Interest 14.5 100.0% Soil Map—King County Area, Washington Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/19/2018 Page 3 of 3 Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX B WWHM REPORTS WWHM2012 PROJECT REPORT 181220_Infil Trench 12/20/2018 9:56:14 AM Page 2 General Model Information Project Name:181220_Infil Trench Site Name:Upper Balch Pit Site Address: City:Renton, WA Report Date:12/20/2018 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 181220_Infil Trench 12/20/2018 9:56:14 AM Page 3 Landuse Basin Data Predeveloped Land Use Predeveloped Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 14.43 Pervious Total 14.43 Impervious Land Use acre Impervious Total 0 Basin Total 14.43 Element Flows To: Surface Interflow Groundwater 181220_Infil Trench 12/20/2018 9:56:14 AM Page 4 Mitigated Land Use Developed Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 14.43 Pervious Total 14.43 Impervious Land Use acre Impervious Total 0 Basin Total 14.43 Element Flows To: Surface Interflow Groundwater Infiltration Trench Infiltration Trench 181220_Infil Trench 12/20/2018 9:56:14 AM Page 5 Routing Elements Predeveloped Routing 181220_Infil Trench 12/20/2018 9:56:14 AM Page 6 Mitigated Routing Infiltration Trench Bottom Length:650.00 ft. Bottom Width:10.00 ft. Trench bottom slope 1:0 To 1 Trench Left side slope 0:0 To 1 Trench right side slope 2:0 To 1 Material thickness of first layer:8 Pour Space of material for first layer:0.4 Material thickness of second layer:0 Pour Space of material for second layer:0 Material thickness of third layer:0 Pour Space of material for third layer:0 Infiltration On Infiltration rate:7 Infiltration safety factor:1 Total Volume Infiltrated (ac-ft.):1143.909 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):1143.909 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Discharge Structure Riser Height:8 ft. Riser Diameter:18 in. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.149 0.000 0.000 0.000 0.1000 0.149 0.006 0.000 1.053 0.2000 0.149 0.011 0.000 1.053 0.3000 0.149 0.017 0.000 1.053 0.4000 0.149 0.023 0.000 1.053 0.5000 0.149 0.029 0.000 1.053 0.6000 0.149 0.035 0.000 1.053 0.7000 0.149 0.041 0.000 1.053 0.8000 0.149 0.047 0.000 1.053 0.9000 0.149 0.053 0.000 1.053 1.0000 0.149 0.059 0.000 1.053 1.1000 0.149 0.065 0.000 1.053 1.2000 0.149 0.071 0.000 1.053 1.3000 0.149 0.077 0.000 1.053 1.4000 0.149 0.083 0.000 1.053 1.5000 0.149 0.089 0.000 1.053 1.6000 0.149 0.095 0.000 1.053 1.7000 0.149 0.101 0.000 1.053 1.8000 0.149 0.107 0.000 1.053 1.9000 0.149 0.113 0.000 1.053 2.0000 0.149 0.119 0.000 1.053 2.1000 0.149 0.125 0.000 1.053 2.2000 0.149 0.131 0.000 1.053 2.3000 0.149 0.137 0.000 1.053 181220_Infil Trench 12/20/2018 9:56:14 AM Page 7 2.4000 0.149 0.143 0.000 1.053 2.5000 0.149 0.149 0.000 1.053 2.6000 0.149 0.155 0.000 1.053 2.7000 0.149 0.161 0.000 1.053 2.8000 0.149 0.167 0.000 1.053 2.9000 0.149 0.173 0.000 1.053 3.0000 0.149 0.179 0.000 1.053 3.1000 0.149 0.185 0.000 1.053 3.2000 0.149 0.191 0.000 1.053 3.3000 0.149 0.197 0.000 1.053 3.4000 0.149 0.202 0.000 1.053 3.5000 0.149 0.208 0.000 1.053 3.6000 0.149 0.214 0.000 1.053 3.7000 0.149 0.220 0.000 1.053 3.8000 0.149 0.226 0.000 1.053 3.9000 0.149 0.232 0.000 1.053 4.0000 0.149 0.238 0.000 1.053 4.1000 0.149 0.244 0.000 1.053 4.2000 0.149 0.250 0.000 1.053 4.3000 0.149 0.256 0.000 1.053 4.4000 0.149 0.262 0.000 1.053 4.5000 0.149 0.268 0.000 1.053 4.6000 0.149 0.274 0.000 1.053 4.7000 0.149 0.280 0.000 1.053 4.8000 0.149 0.286 0.000 1.053 4.9000 0.149 0.292 0.000 1.053 5.0000 0.149 0.298 0.000 1.053 5.1000 0.149 0.304 0.000 1.053 5.2000 0.149 0.310 0.000 1.053 5.3000 0.149 0.316 0.000 1.053 5.4000 0.149 0.322 0.000 1.053 5.5000 0.149 0.328 0.000 1.053 5.6000 0.149 0.334 0.000 1.053 5.7000 0.149 0.340 0.000 1.053 5.8000 0.149 0.346 0.000 1.053 5.9000 0.149 0.352 0.000 1.053 6.0000 0.149 0.358 0.000 1.053 6.1000 0.149 0.364 0.000 1.053 6.2000 0.149 0.370 0.000 1.053 6.3000 0.149 0.376 0.000 1.053 6.4000 0.149 0.382 0.000 1.053 6.5000 0.149 0.388 0.000 1.053 6.6000 0.149 0.393 0.000 1.053 6.7000 0.149 0.399 0.000 1.053 6.8000 0.149 0.405 0.000 1.053 6.9000 0.149 0.411 0.000 1.053 7.0000 0.149 0.417 0.000 1.053 7.1000 0.149 0.423 0.000 1.053 7.2000 0.149 0.429 0.000 1.053 7.3000 0.149 0.435 0.000 1.053 7.4000 0.149 0.441 0.000 1.053 7.5000 0.149 0.447 0.000 1.053 7.6000 0.149 0.453 0.000 1.053 7.7000 0.149 0.459 0.000 1.053 7.8000 0.149 0.465 0.000 1.053 7.9000 0.149 0.471 0.000 1.053 8.0000 0.149 0.477 0.000 1.053 8.1000 0.149 0.492 0.502 1.053 181220_Infil Trench 12/20/2018 9:56:14 AM Page 8 8.2000 0.149 0.507 1.404 1.053 8.3000 0.149 0.522 2.501 1.053 8.4000 0.149 0.537 3.632 1.053 8.5000 0.149 0.552 4.639 1.053 8.6000 0.149 0.567 5.401 1.053 8.7000 0.149 0.582 5.892 1.053 8.8000 0.149 0.596 6.338 1.053 8.9000 0.149 0.611 6.723 1.053 9.0000 0.149 0.626 7.086 1.053 181220_Infil Trench 12/20/2018 9:56:14 AM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:14.43 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:14.43 Total Impervious Area:0 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.424254 5 year 0.666307 10 year 0.803483 25 year 0.948809 50 year 1.038737 100 year 1.115225 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.417 0.000 1950 0.520 0.000 1951 0.934 0.000 1952 0.294 0.000 1953 0.238 0.000 1954 0.366 0.000 1955 0.583 0.000 1956 0.464 0.000 1957 0.374 0.000 1958 0.422 0.000 181220_Infil Trench 12/20/2018 10:01:44 AM Page 10 1959 0.362 0.000 1960 0.632 0.000 1961 0.356 0.000 1962 0.222 0.000 1963 0.304 0.000 1964 0.401 0.000 1965 0.287 0.000 1966 0.276 0.000 1967 0.577 0.000 1968 0.360 0.000 1969 0.352 0.000 1970 0.290 0.000 1971 0.310 0.000 1972 0.696 0.000 1973 0.316 0.000 1974 0.343 0.000 1975 0.465 0.000 1976 0.336 0.000 1977 0.040 0.000 1978 0.295 0.000 1979 0.178 0.000 1980 0.659 0.000 1981 0.264 0.000 1982 0.507 0.000 1983 0.454 0.000 1984 0.280 0.000 1985 0.166 0.000 1986 0.735 0.000 1987 0.650 0.000 1988 0.257 0.000 1989 0.167 0.000 1990 1.360 0.000 1991 0.819 0.000 1992 0.316 0.000 1993 0.329 0.000 1994 0.111 0.000 1995 0.472 0.000 1996 0.994 0.000 1997 0.831 0.000 1998 0.188 0.000 1999 0.779 0.000 2000 0.328 0.000 2001 0.059 0.000 2002 0.359 0.000 2003 0.459 0.000 2004 0.594 0.000 2005 0.426 0.000 2006 0.502 0.000 2007 1.009 0.000 2008 1.302 0.000 2009 0.639 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.3600 0.0000 2 1.3022 0.0000 3 1.0095 0.0000 181220_Infil Trench 12/20/2018 10:01:44 AM Page 11 4 0.9941 0.0000 5 0.9342 0.0000 6 0.8310 0.0000 7 0.8189 0.0000 8 0.7793 0.0000 9 0.7353 0.0000 10 0.6957 0.0000 11 0.6593 0.0000 12 0.6504 0.0000 13 0.6394 0.0000 14 0.6317 0.0000 15 0.5938 0.0000 16 0.5830 0.0000 17 0.5769 0.0000 18 0.5196 0.0000 19 0.5068 0.0000 20 0.5023 0.0000 21 0.4717 0.0000 22 0.4648 0.0000 23 0.4640 0.0000 24 0.4586 0.0000 25 0.4544 0.0000 26 0.4260 0.0000 27 0.4218 0.0000 28 0.4167 0.0000 29 0.4007 0.0000 30 0.3744 0.0000 31 0.3656 0.0000 32 0.3618 0.0000 33 0.3598 0.0000 34 0.3595 0.0000 35 0.3564 0.0000 36 0.3520 0.0000 37 0.3430 0.0000 38 0.3360 0.0000 39 0.3289 0.0000 40 0.3280 0.0000 41 0.3160 0.0000 42 0.3158 0.0000 43 0.3105 0.0000 44 0.3044 0.0000 45 0.2948 0.0000 46 0.2944 0.0000 47 0.2903 0.0000 48 0.2869 0.0000 49 0.2805 0.0000 50 0.2759 0.0000 51 0.2635 0.0000 52 0.2567 0.0000 53 0.2381 0.0000 54 0.2218 0.0000 55 0.1880 0.0000 56 0.1781 0.0000 57 0.1675 0.0000 58 0.1664 0.0000 59 0.1105 0.0000 60 0.0588 0.0000 61 0.0400 0.0000 181220_Infil Trench 12/20/2018 10:01:44 AM Page 12 181220_Infil Trench 12/20/2018 10:01:44 AM Page 13 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2121 17579 0 0 Pass 0.2205 16228 0 0 Pass 0.2288 15062 0 0 Pass 0.2372 13871 0 0 Pass 0.2455 12868 0 0 Pass 0.2539 11920 0 0 Pass 0.2622 10915 0 0 Pass 0.2706 10160 0 0 Pass 0.2789 9458 0 0 Pass 0.2873 8752 0 0 Pass 0.2956 8190 0 0 Pass 0.3040 7657 0 0 Pass 0.3123 7080 0 0 Pass 0.3207 6611 0 0 Pass 0.3290 6145 0 0 Pass 0.3374 5790 0 0 Pass 0.3457 5461 0 0 Pass 0.3541 5101 0 0 Pass 0.3624 4819 0 0 Pass 0.3708 4547 0 0 Pass 0.3791 4254 0 0 Pass 0.3875 4030 0 0 Pass 0.3958 3805 0 0 Pass 0.4042 3551 0 0 Pass 0.4125 3347 0 0 Pass 0.4209 3153 0 0 Pass 0.4292 2954 0 0 Pass 0.4376 2791 0 0 Pass 0.4459 2616 0 0 Pass 0.4543 2449 0 0 Pass 0.4626 2316 0 0 Pass 0.4710 2175 0 0 Pass 0.4793 2030 0 0 Pass 0.4877 1910 0 0 Pass 0.4960 1790 0 0 Pass 0.5044 1694 0 0 Pass 0.5127 1597 0 0 Pass 0.5211 1483 0 0 Pass 0.5294 1385 0 0 Pass 0.5378 1299 0 0 Pass 0.5461 1221 0 0 Pass 0.5545 1158 0 0 Pass 0.5628 1102 0 0 Pass 0.5712 1048 0 0 Pass 0.5795 998 0 0 Pass 0.5879 933 0 0 Pass 0.5962 884 0 0 Pass 0.6046 841 0 0 Pass 0.6129 791 0 0 Pass 0.6213 743 0 0 Pass 0.6296 718 0 0 Pass 0.6380 673 0 0 Pass 0.6463 633 0 0 Pass 181220_Infil Trench 12/20/2018 10:01:44 AM Page 14 0.6547 598 0 0 Pass 0.6630 565 0 0 Pass 0.6714 540 0 0 Pass 0.6797 500 0 0 Pass 0.6881 473 0 0 Pass 0.6964 437 0 0 Pass 0.7048 403 0 0 Pass 0.7131 366 0 0 Pass 0.7215 348 0 0 Pass 0.7298 325 0 0 Pass 0.7382 296 0 0 Pass 0.7465 275 0 0 Pass 0.7549 258 0 0 Pass 0.7632 235 0 0 Pass 0.7715 218 0 0 Pass 0.7799 201 0 0 Pass 0.7882 180 0 0 Pass 0.7966 158 0 0 Pass 0.8049 146 0 0 Pass 0.8133 129 0 0 Pass 0.8216 119 0 0 Pass 0.8300 110 0 0 Pass 0.8383 97 0 0 Pass 0.8467 92 0 0 Pass 0.8550 82 0 0 Pass 0.8634 76 0 0 Pass 0.8717 69 0 0 Pass 0.8801 61 0 0 Pass 0.8884 55 0 0 Pass 0.8968 48 0 0 Pass 0.9051 41 0 0 Pass 0.9135 38 0 0 Pass 0.9218 33 0 0 Pass 0.9302 27 0 0 Pass 0.9385 22 0 0 Pass 0.9469 21 0 0 Pass 0.9552 20 0 0 Pass 0.9636 19 0 0 Pass 0.9719 17 0 0 Pass 0.9803 14 0 0 Pass 0.9886 12 0 0 Pass 0.9970 9 0 0 Pass 1.0053 4 0 0 Pass 1.0137 3 0 0 Pass 1.0220 3 0 0 Pass 1.0304 3 0 0 Pass 1.0387 3 0 0 Pass 181220_Infil Trench 12/20/2018 10:01:44 AM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 181220_Infil Trench 12/20/2018 10:01:44 AM Page 16 LID Report 181220_Infil Trench 12/20/2018 10:02:07 AM Page 17 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 181220_Infil Trench 12/20/2018 10:02:07 AM Page 18 Appendix Predeveloped Schematic 181220_Infil Trench 12/20/2018 10:02:08 AM Page 19 Mitigated Schematic 181220_Infil Trench 12/20/2018 10:02:09 AM Page 20 Predeveloped UCI File 181220_Infil Trench 12/20/2018 10:02:09 AM Page 21 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 181220_Infil Trench.wdm MESSU 25 Mit181220_Infil Trench.MES 27 Mit181220_Infil Trench.L61 28 Mit181220_Infil Trench.L62 30 POC181220_Infil Trench1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Infiltration Trench MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 181220_Infil Trench 12/20/2018 10:02:09 AM Page 22 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 181220_Infil Trench 12/20/2018 10:02:09 AM Page 23 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Developed*** PERLND 16 14.43 RCHRES 1 2 PERLND 16 14.43 RCHRES 1 3 ******Routing****** PERLND 16 14.43 COPY 1 12 PERLND 16 14.43 COPY 1 13 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Infiltration Tre-005 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.12 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES 181220_Infil Trench 12/20/2018 10:02:09 AM Page 24 SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.149219 0.000000 0.000000 0.000000 0.100000 0.149219 0.005969 0.000000 1.053241 0.200000 0.149219 0.011938 0.000000 1.053241 0.300000 0.149219 0.017906 0.000000 1.053241 0.400000 0.149219 0.023875 0.000000 1.053241 0.500000 0.149219 0.029844 0.000000 1.053241 0.600000 0.149219 0.035813 0.000000 1.053241 0.700000 0.149219 0.041781 0.000000 1.053241 0.800000 0.149219 0.047750 0.000000 1.053241 0.900000 0.149219 0.053719 0.000000 1.053241 1.000000 0.149219 0.059688 0.000000 1.053241 1.100000 0.149219 0.065657 0.000000 1.053241 1.200000 0.149219 0.071625 0.000000 1.053241 1.300000 0.149219 0.077594 0.000000 1.053241 1.400000 0.149219 0.083563 0.000000 1.053241 1.500000 0.149219 0.089532 0.000000 1.053241 1.600000 0.149219 0.095500 0.000000 1.053241 1.700000 0.149219 0.101469 0.000000 1.053241 1.800000 0.149219 0.107438 0.000000 1.053241 1.900000 0.149219 0.113407 0.000000 1.053241 2.000000 0.149219 0.119376 0.000000 1.053241 2.100000 0.149219 0.125344 0.000000 1.053241 2.200000 0.149219 0.131313 0.000000 1.053241 2.300000 0.149219 0.137282 0.000000 1.053241 2.400000 0.149219 0.143251 0.000000 1.053241 2.500000 0.149219 0.149219 0.000000 1.053241 2.600000 0.149219 0.155188 0.000000 1.053241 2.700000 0.149219 0.161157 0.000000 1.053241 2.800000 0.149219 0.167126 0.000000 1.053241 2.900000 0.149219 0.173095 0.000000 1.053241 3.000000 0.149219 0.179063 0.000000 1.053241 3.100000 0.149219 0.185032 0.000000 1.053241 3.200000 0.149219 0.191001 0.000000 1.053241 3.300000 0.149219 0.196970 0.000000 1.053241 3.400000 0.149219 0.202938 0.000000 1.053241 3.500000 0.149219 0.208907 0.000000 1.053241 3.600000 0.149219 0.214876 0.000000 1.053241 3.700000 0.149219 0.220845 0.000000 1.053241 3.800000 0.149219 0.226814 0.000000 1.053241 3.900000 0.149219 0.232782 0.000000 1.053241 4.000000 0.149219 0.238751 0.000000 1.053241 4.100000 0.149219 0.244720 0.000000 1.053241 4.200000 0.149219 0.250689 0.000000 1.053241 4.300000 0.149219 0.256657 0.000000 1.053241 4.400000 0.149219 0.262626 0.000000 1.053241 4.500000 0.149219 0.268595 0.000000 1.053241 4.600000 0.149219 0.274564 0.000000 1.053241 4.700000 0.149219 0.280533 0.000000 1.053241 4.800000 0.149219 0.286501 0.000000 1.053241 4.900000 0.149219 0.292470 0.000000 1.053241 5.000000 0.149219 0.298439 0.000000 1.053241 5.100000 0.149219 0.304408 0.000000 1.053241 5.200000 0.149219 0.310376 0.000000 1.053241 5.300000 0.149219 0.316345 0.000000 1.053241 5.400000 0.149219 0.322314 0.000000 1.053241 5.500000 0.149219 0.328283 0.000000 1.053241 5.600000 0.149219 0.334252 0.000000 1.053241 5.700000 0.149219 0.340220 0.000000 1.053241 5.800000 0.149219 0.346189 0.000000 1.053241 5.900000 0.149219 0.352158 0.000000 1.053241 6.000000 0.149219 0.358127 0.000000 1.053241 6.100000 0.149219 0.364096 0.000000 1.053241 181220_Infil Trench 12/20/2018 10:02:09 AM Page 25 6.200000 0.149219 0.370064 0.000000 1.053241 6.300000 0.149219 0.376033 0.000000 1.053241 6.400000 0.149219 0.382002 0.000000 1.053241 6.500000 0.149219 0.387971 0.000000 1.053241 6.600000 0.149219 0.393939 0.000000 1.053241 6.700000 0.149219 0.399908 0.000000 1.053241 6.800000 0.149219 0.405877 0.000000 1.053241 6.900000 0.149219 0.411846 0.000000 1.053241 7.000000 0.149219 0.417815 0.000000 1.053241 7.100000 0.149219 0.423783 0.000000 1.053241 7.200000 0.149219 0.429752 0.000000 1.053241 7.300000 0.149219 0.435721 0.000000 1.053241 7.400000 0.149219 0.441690 0.000000 1.053241 7.500000 0.149219 0.447658 0.000000 1.053241 7.600000 0.149219 0.453627 0.000000 1.053241 7.700000 0.149219 0.459596 0.000000 1.053241 7.800000 0.149219 0.465565 0.000000 1.053241 7.900000 0.149219 0.471534 0.000000 1.053241 8.000000 0.149219 0.477502 0.000000 1.053241 8.100000 0.149219 0.492424 0.502178 1.053241 8.200000 0.149219 0.507346 1.404464 1.053241 8.300000 0.149219 0.522268 2.501261 1.053241 8.400000 0.149219 0.537190 3.632201 1.053241 8.500000 0.149219 0.552112 4.639092 1.053241 8.600000 0.149219 0.567034 5.401220 1.053241 8.700000 0.149219 0.581956 5.892534 1.053241 8.800000 0.149219 0.596878 6.338508 1.053241 8.900000 0.149219 0.611800 6.723003 1.053241 9.000000 0.149219 0.626722 7.086668 1.053241 9.100000 0.149219 0.641644 7.432560 1.053241 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1001 FLOW ENGL REPL RCHRES 1 HYDR O 2 1 1 WDM 1002 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1003 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 181220_Infil Trench 12/20/2018 10:02:09 AM Page 26 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN 181220_Infil Trench 12/20/2018 10:02:09 AM Page 27 Predeveloped HSPF Message File 181220_Infil Trench 12/20/2018 10:02:09 AM Page 28 Mitigated HSPF Message File 181220_Infil Trench 12/20/2018 10:02:09 AM Page 29 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2018; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 2 General Model Information Project Name:181130_Trench and Pond_SSD Site Name:Segale Site Address:301 Monroe Ave NE City:Renton, WA Report Date:11/30/2018 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 3 Landuse Basin Data Predeveloped Land Use Predeveloped Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 14.43 Pervious Total 14.43 Impervious Land Use acre Impervious Total 0 Basin Total 14.43 Element Flows To: Surface Interflow Groundwater 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 4 Mitigated Land Use Developed Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 7.33 Pervious Total 7.33 Impervious Land Use acre ROADS FLAT 3.29 ROOF TOPS FLAT 3.8 Impervious Total 7.09 Basin Total 14.42 Element Flows To: Surface Interflow Groundwater SSD_Infil and DetentionSSD_Infil and Detention 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 5 Routing Elements Predeveloped Routing 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 6 Mitigated Routing SSD_Infil and Detention Depth:8 ft. Element Flows To: Outlet 1 Outlet 2 SSD Table Hydraulic Table Stage Area Volume Outlet Infilt/ (feet) (ac.) (ac-ft.) Struct Recharge NotUsed NotUsed NotUsed 0.000 0.143 0.000 0.000 1.009 0.000 0.000 0.000 0.500 0.143 0.022 0.000 1.009 0.000 0.000 0.000 1.000 0.143 0.043 0.000 1.009 0.000 0.000 0.000 1.500 0.143 0.065 0.000 1.009 0.000 0.000 0.000 2.000 0.143 0.086 0.000 1.009 0.000 0.000 0.000 2.500 0.143 0.108 0.000 1.009 0.000 0.000 0.000 3.000 0.143 0.129 0.000 1.009 0.000 0.000 0.000 3.500 0.143 0.151 0.000 1.009 0.000 0.000 0.000 4.000 0.143 0.172 0.000 1.009 0.000 0.000 0.000 4.500 0.143 0.194 0.000 1.009 0.000 0.000 0.000 5.000 0.143 0.215 0.000 1.009 0.000 0.000 0.000 5.500 0.143 0.237 0.000 1.009 0.000 0.000 0.000 6.000 0.143 0.258 0.000 1.009 0.000 0.000 0.000 6.500 0.143 0.280 0.000 1.009 0.000 0.000 0.000 7.000 0.143 0.301 0.000 1.009 0.000 0.000 0.000 7.500 0.143 0.323 0.000 1.009 0.000 0.000 0.000 8.000 0.143 0.344 0.000 1.009 0.000 0.000 0.000 181130_Trench and Pond_SSD 11/30/2018 1:23:59 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:14.43 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:7.33 Total Impervious Area:7.09 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.477419 5 year 0.531494 10 year 0.554884 25 year 0.575898 50 year 0.587336 100 year 0.596247 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.417 0.000 1950 0.520 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.5196 0.0000 2 0.4167 0.0000 181130_Trench and Pond_SSD 11/30/2018 1:24:13 PM Page 8 181130_Trench and Pond_SSD 11/30/2018 1:24:13 PM Page 9 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2387 703 0 0 Pass 0.2422 685 0 0 Pass 0.2458 669 0 0 Pass 0.2493 650 0 0 Pass 0.2528 635 0 0 Pass 0.2563 618 0 0 Pass 0.2598 603 0 0 Pass 0.2634 583 0 0 Pass 0.2669 573 0 0 Pass 0.2704 558 0 0 Pass 0.2739 547 0 0 Pass 0.2774 532 0 0 Pass 0.2810 520 0 0 Pass 0.2845 506 0 0 Pass 0.2880 490 0 0 Pass 0.2915 477 0 0 Pass 0.2951 465 0 0 Pass 0.2986 457 0 0 Pass 0.3021 444 0 0 Pass 0.3056 435 0 0 Pass 0.3091 420 0 0 Pass 0.3127 413 0 0 Pass 0.3162 400 0 0 Pass 0.3197 384 0 0 Pass 0.3232 370 0 0 Pass 0.3267 364 0 0 Pass 0.3303 354 0 0 Pass 0.3338 346 0 0 Pass 0.3373 334 0 0 Pass 0.3408 326 0 0 Pass 0.3444 313 0 0 Pass 0.3479 305 0 0 Pass 0.3514 293 0 0 Pass 0.3549 281 0 0 Pass 0.3584 268 0 0 Pass 0.3620 259 0 0 Pass 0.3655 250 0 0 Pass 0.3690 241 0 0 Pass 0.3725 234 0 0 Pass 0.3760 226 0 0 Pass 0.3796 219 0 0 Pass 0.3831 207 0 0 Pass 0.3866 200 0 0 Pass 0.3901 188 0 0 Pass 0.3937 176 0 0 Pass 0.3972 156 0 0 Pass 0.4007 147 0 0 Pass 0.4042 139 0 0 Pass 0.4077 133 0 0 Pass 0.4113 124 0 0 Pass 0.4148 119 0 0 Pass 0.4183 110 0 0 Pass 0.4218 106 0 0 Pass 181130_Trench and Pond_SSD 11/30/2018 1:24:13 PM Page 10 0.4253 100 0 0 Pass 0.4289 90 0 0 Pass 0.4324 87 0 0 Pass 0.4359 82 0 0 Pass 0.4394 74 0 0 Pass 0.4430 69 0 0 Pass 0.4465 63 0 0 Pass 0.4500 60 0 0 Pass 0.4535 57 0 0 Pass 0.4570 52 0 0 Pass 0.4606 48 0 0 Pass 0.4641 39 0 0 Pass 0.4676 28 0 0 Pass 0.4711 22 0 0 Pass 0.4746 20 0 0 Pass 0.4782 16 0 0 Pass 0.4817 13 0 0 Pass 0.4852 12 0 0 Pass 0.4887 8 0 0 Pass 0.4923 4 0 0 Pass 0.4958 2 0 0 Pass 0.4993 1 0 0 Pass 0.5028 1 0 0 Pass 0.5063 1 0 0 Pass 0.5099 1 0 0 Pass 0.5134 1 0 0 Pass 0.5169 1 0 0 Pass 0.5204 0 0 0 Pass 0.5239 0 0 0 Pass 0.5275 0 0 0 Pass 0.5310 0 0 0 Pass 0.5345 0 0 0 Pass 0.5380 0 0 0 Pass 0.5416 0 0 0 Pass 0.5451 0 0 0 Pass 0.5486 0 0 0 Pass 0.5521 0 0 0 Pass 0.5556 0 0 0 Pass 0.5592 0 0 0 Pass 0.5627 0 0 0 Pass 0.5662 0 0 0 Pass 0.5697 0 0 0 Pass 0.5733 0 0 0 Pass 0.5768 0 0 0 Pass 0.5803 0 0 0 Pass 0.5838 0 0 0 Pass 0.5873 0 0 0 Pass 181130_Trench and Pond_SSD 11/30/2018 1:24:13 PM Page 11 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 181130_Trench and Pond_SSD 11/30/2018 1:24:13 PM Page 12 LID Report 181130_Trench and Pond_SSD 11/30/2018 1:24:20 PM Page 13 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 181130_Trench and Pond_SSD 11/30/2018 1:24:20 PM Page 14 Appendix Predeveloped Schematic 181130_Trench and Pond_SSD 11/30/2018 1:24:21 PM Page 15 Mitigated Schematic 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 16 Predeveloped UCI File 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 17 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 181130_Trench and Pond_SSD.wdm MESSU 25 Mit181130_Trench and Pond_SSD.MES 27 Mit181130_Trench and Pond_SSD.L61 28 Mit181130_Trench and Pond_SSD.L62 30 POC181130_Trench and Pond_SSD1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 4 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 SSD_Infil and Detention MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 18 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 4 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 4 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 19 1 400 0.01 0.1 0.1 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 4 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Developed*** PERLND 16 7.33 RCHRES 1 2 PERLND 16 7.33 RCHRES 1 3 IMPLND 1 3.29 RCHRES 1 5 IMPLND 4 3.8 RCHRES 1 5 ******Routing****** PERLND 16 7.33 COPY 1 12 IMPLND 1 3.29 COPY 1 15 IMPLND 4 3.8 COPY 1 15 PERLND 16 7.33 COPY 1 13 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 SSD_Infil and De-007 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 20 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 17 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.143000 0.000000 0.000000 0.000000 0.500000 0.143000 0.022000 0.000000 1.009342 1.000000 0.143000 0.043000 0.000000 1.009342 1.500000 0.143000 0.065000 0.000000 1.009342 2.000000 0.143000 0.086000 0.000000 1.009342 2.500000 0.143000 0.108000 0.000000 1.009342 3.000000 0.143000 0.129000 0.000000 1.009342 3.500000 0.143000 0.151000 0.000000 1.009342 4.000000 0.143000 0.172000 0.000000 1.009342 4.500000 0.143000 0.194000 0.000000 1.009342 5.000000 0.143000 0.215000 0.000000 1.009342 5.500000 0.143000 0.237000 0.000000 1.009342 6.000000 0.143000 0.258000 0.000000 1.009342 6.500000 0.143000 0.280000 0.000000 1.009342 7.000000 0.143000 0.301000 0.000000 1.009342 7.500000 0.143000 0.323000 0.000000 1.009342 8.000000 0.143000 0.344000 0.000000 1.009342 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1001 FLOW ENGL REPL RCHRES 1 HYDR O 2 1 1 WDM 1002 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1003 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 21 <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 22 Predeveloped HSPF Message File 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 23 Mitigated HSPF Message File ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 22:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.5210E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 22:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -1.553E+04 1.2463 1.2463E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 22:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6168E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 22:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -2.858E+04 2.2940 2.2940 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 23: 0 RCHRES: 1 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 24 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6753E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 23: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -3.654E+04 2.9333 2.9333E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 23:15 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7112E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 23:15 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -4.142E+04 3.3251 3.3251E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 23:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7340E+04 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 25 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 23:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -4.454E+04 3.5751 3.5750E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 23:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7264E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 23:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -4.350E+04 3.4914 3.4913E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/16 24: 0 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7182E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/16 24: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 26 Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -4.238E+04 3.4020 3.4020 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/17 0:15 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6967E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/17 0:15 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -3.945E+04 3.1666 3.1666E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/17 0:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6625E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/17 0:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -3.480E+04 2.7936 2.7936E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/17 0:45 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 27 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6213E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/17 0:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -2.919E+04 2.3433 2.3433E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/17 1: 0 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.5741E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/17 1: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -2.275E+04 1.8263 1.8263 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1949/ 2/17 1:15 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 28 NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.5216E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1949/ 2/17 1:15 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -1.561E+04 1.2533 1.2533 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 4: 0 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.5077E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 4: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -1.371E+04 1.1008 1.1008E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 4:15 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.5824E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 4:15 RCHRES: 1 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 29 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -2.388E+04 1.9171 1.9171 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 4:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6572E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 4:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -3.408E+04 2.7356 2.7356E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 4:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.6810E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 4:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -3.732E+04 2.9960 2.9960 2 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 30 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 5: 0 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7460E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 5: 0 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -4.617E+04 3.7058 3.7058E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 5:15 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.7926E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 5:15 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -5.252E+04 4.2154 4.2153E+00 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 5:30 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 31 simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.8030E+04 ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 5:30 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -5.394E+04 4.3295 4.3295 2 ERROR/WARNING ID: 341 6 DATE/TIME: 1951/ 2/ 9 5:45 RCHRES: 1 The volume of water in this reach/mixed reservoir is greater than the value in the "volume" column of the last row of RCHTAB(). To continue the simulation the table has been extrapolated, based on information contained in the last two rows. This will usually result in some loss of accuracy. If depth is being calculated it will also cause an error condition. Relevant data are: NROWS V1 V2 VOL 17 1.4070E+04 1.4985E+04 1.8312E+04 The count for the WARNING printed above has reached its maximum. If the condition is encountered again the message will not be repeated. ERROR/WARNING ID: 341 5 DATE/TIME: 1951/ 2/ 9 5:45 RCHRES: 1 Calculation of relative depth, using Newton's method of successive approximations, converged to an invalid value (not in range 0.0 to 1.0). Probably ftable was extrapolated. If extrapolation was small, no problem. Remedy; extend ftable. Relevant data are: A B C RDEP1 RDEP2 COUNT 0.0000E+00 1.2458E+04 -5.777E+04 4.6373 4.6373 2 181130_Trench and Pond_SSD 11/30/2018 1:24:22 PM Page 32 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2018; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX C OTHER REPORTS RAEDEKE ASSOCIATES, INC. 5711 NE 63rd Street Seattle, Washington 98115 (206) 525-8122 Fax: (206) 526-2880 TECHNICAL MEMORANDUM July 30, 2010 To: Mr. Mark Segale, Segale Properties, Inc. From: Christopher W. Wright, Raedeke Associates, Inc. RE: Upper Balch Pit - Wetland Reconnaissance (R.A.I. No. 2000-011-002) The purpose of this document is to summarize the results of our wetland reconnaissance of the Upper Balch Pit property on July 28, 2010. PROJECT LOCATION The Upper Balch Pit is a 14-acre property located south of NE 4th Street and west of Monroe Avenue NE in Renton, Washington. This places the property within a portion of Section 16 Township 23 North Range 5 East, W.M. DEFINITIONS AND METHODS We based our wetland investigation upon the guidelines of the U.S. Army Corps of Engineers (COE) Wetlands Delineation Manual (Environmental Laboratory 1987), as revised in the Washington State Wetlands Identification and Delineation Manual published by the Washington Department of Ecology (WDOE 1997). The WDOE wetlands manual is required by state law for all local jurisdictions, is consistent with the 1987 COE wetland delineation manual with respect to wetland identification and delineation, and incorporates subsequent amendments and clarifications provided by the COE. The COE, which requires use of the 1987 delineation manual, as amended, has federal regulatory jurisdiction of the dredging or filling of "Waters of the United States," including wetlands. As outlined in this methodology, the interaction of hydrophytic vegetation, hydric soil, and wetland hydrology must be present for an area to be classified as wetland. To be consistent with current regulations, field investigations were conducted in a manner consistent with the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys and Coast Region (COE 2010). Mr. Mark Segale July 30, 2010 Page 2 FIELD INVESTIGATION I visited the site on July 28, 2010 for the purpose of determining if wetlands were present on the site. RESULTS General Site Description The Upper Balch Pit is a reclaimed gravel mine. The lowest portions of the site are used to dispose of fill material from other sites. The lowest portions of the site are unvegetated. The side slopes of the Upper Balch Pit are vegetated with a mix of deciduous trees and shrubs common to the region. Central and southern portions of the Upper Balch Pit contain a vegetation community consisting of grasses, herbs, and shrubs. A storm drainage pipe conveys water from Monroe Avenue NE to the lowest portion of the Upper Balch Pit along the eastern slope of the site. Observed Conditions The lower portions of the Upper Balch Pit are undergoing active reclamation. Fill material has been imported to the site and spread over the ground surface. As a result this portion of the site is currently unvegetated. The fill consists of material of differing permeability and did not exhibit any hydric soil characteristics. Surface water runoff from the pipe along the eastern slope collects as surface water in portions of the site on less permeable material placed as part of the reclamation project. The surface water infiltrates into the more permeable areas and does not constitute wetland hydrology conditions. The eastern and southern slopes of the Upper Balch Pit contain a vegetation community consisting of black cottonwood (Populus balsamifera), big-leaf maple (Acer macrophylla), and red alder (Alnus rubra). The shrub understory is predominantly Himalayan blackberry (Rubus armeniancus). Herbaceous plants observed on the slopes include foxglove (Digitalis sp.), common horsetail (Equisetum arvense), and stinging nettle (Urtica dioicia). Soils on the slopes are gravely sandy loams that did not exhibit any redoximorphic features or other indicators of wetland conditions. No water was observed on the side slopes. The central portions of the Upper Balch Pit, not undergoing active reclamation, as well as the northern and western side slopes, support a vegetation community comprised of Scotch broom (Cytisus scoparius), Himalayan blackberry, common tansy (Tanacetum vulgare), Canadian thistle (Cirsium arvense), velvet grass (Holcus lanatus), and tall fescue (Festuca arundinacea). Soils observed in the central portions of the site appear to be previously placed fill material with no hydric soil indicators. No hydrology was observed in the central portions of the site. Mr. Mark Segale July 30, 2010 Page 3 SUMMARY In summary, based on our observations and analysis, the Upper Balch Pit property contains no areas that exhibit wetland characteristics. The areas with some surface water are the result of storm drainage discharge to the site from the adjoining roadways. LIMITATIONS We have prepared this letter for the exclusive use of the Segale Properties, Inc. and their consultants. No other person or agency may rely upon the information, analysis, or conclusions contained herein without permission from Segale Properties, Inc. The determination of ecological system classifications, functions, values, and boundaries is an inexact science, and different individuals and agencies may reach different conclusions. With regard to wetlands, the final determination of their boundaries for regulatory purposes is the responsibility of the various resource agencies that regulate development activities in or near wetlands. We cannot guarantee the outcome of such agency determinations. Therefore, the conclusions of this report should be reviewed by the appropriate regulatory agencies prior to any detailed site planning or construction activities. We warrant that the work performed conforms to standards generally accepted in our field, and prepared substantially in accordance with then-current technical guidelines and criteria. The conclusions of this report represent the results of our analysis of the information provided by the project proponents and their consultants, together with information gathered in the course of this study. No other warranty, expressed or implied, is made. Thank you for the opportunity to provide this information. If you have any questions or need additional information, please do not hesitate to call me at (206) 525-8122. 1101 S. Fawcett Avenue, Suite 200 Tacoma, Washington 98402 253.383.4940 August 2, 2010 Segale Properties P.O. Box 88028 Tukwila, Washington 98138-2028 Attention: Mark Segale Jami Balint Subject: Geologic and Sensitive Areas Report Upper Balch Pit Renton, Washington File No. 0291-042-00 INTRODUCTION The Upper Balch Pit is located adjacent to and west of Monroe Avenue NE between NE 2nd and NE 4th Streets in Renton, Washington. In the past it has been mined for sand and gravel. During the last ten years some re-filling of the pit has occurred. Plans are to continue filling the pit using fill material as it becomes available. GEOLOGIC SETTING The pit is located in the eastern uplands of Renton in glacially altered terrain. Material removed from the site consists of recessional outwash deposited by melt water from the Vashon glacier and consists of sand and gravel with zones of fine to medium-graded sand. This material was (is) dense and may have been temporarily overridden by the glacial ice during a short term advance. The granular material was mostly removed down to a clayey silt layer (Lacurstine deposit) or in places glacial till, which typically overlies the silt material. Slopes at the boundaries of the pit were generally cut at or near the angle of repose and have remained reasonably stable. At the present time the slopes range up to approximately 70 percent and the average of the steeper slopes typically around 60 percent. Site Planning Civil Engineering Project Management Land Development Consulting APPENDIX D OPERATIONS AND MAINTENANCE MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-3 NO. 1 – DETENTION PONDS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot 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. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Top or Side Slopes of Dam, Berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are not a threat or not interfering with access or maintenance, they do not need to be removed. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment accumulation Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged (If applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Emergency Overflow/Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. Rock missing Only one layer of rock exists above native soil in area five square feet or larger or any exposure of native soil on the spillway. Spillway restored to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-4 NO. 2 – INFILTRATION FACILITIES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot 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. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Infiltration Pond, Top or Side Slopes of Dam, Berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of dams, berms or slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are not a threat to dam, berm, or embankment integrity or not interfering with access or maintenance, they do not need to be removed. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Infiltration Pond, Tank, Vault, Trench, or Small Basin Storage Area Sediment accumulation If two inches or more sediment is present or a percolation test indicates facility is working at or less than 90% of design. Facility infiltrates as designed. Liner damaged (If applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Infiltration Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Infiltration Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-5 NO. 2 – INFILTRATION FACILITIES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and 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 doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. Infiltration Pond, Tank, Vault, Trench, or Small Basin Filter Bags Plugged filter bag (if applicable) Filter bag more than 1/2 full. Replace filter bag or redesign system. Infiltration Pond, Tank, Vault, Trench, or Small Basin Pre- settling Ponds and Vaults Sediment accumulation 6" or more of sediment has accumulated. Pre-settling occurs as designed Infiltration Pond, Rock Filter Plugged rock filter High water level on upstream side of filter remains for extended period of time or little or no water flows through filter during heavy rain storms. Rock filter replaced evaluate need for filter and remove if not necessary. Infiltration Pond Emergency Overflow Spillway Rock missing Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. Spillway restored to design standards. Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-10 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-11 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipe (cont.) Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. 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. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-12 NO. 6 – CONVEYANCE PIPES AND DITCHES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/root growth in pipe Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged pipes Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive vegetation growth Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-14 NO. 8 – ENERGY DISSIPATERS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED. Site Trash and debris Trash and/or debris accumulation. Dissipater clear of trash and/or debris. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Rock Pad Missing or moved rock Only one layer of rock exists above native soil in area five square feet or larger or any exposure of native soil. Rock pad prevents erosion. Dispersion Trench Pipe plugged with sediment Accumulated sediment that exceeds 20% of the design depth. Pipe cleaned/flushed so that it matches design. Not discharging water properly Visual evidence of water discharging at concentrated points along trench (normal condition is a “sheet flow” of water along trench). Water discharges from feature by sheet flow. Perforations plugged Over 1/4 of perforations in pipe are plugged with debris or sediment. Perforations freely discharge flow. Water flows out top of “distributor” catch basin. Water flows out of distributor catch basin during any storm less than the design storm. No flow discharges from distributor catch basin. Receiving area over- saturated Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Gabions Damaged mesh Mesh of gabion broken, twisted or deformed so structure is weakened or rock may fall out. Mesh is intact, no rock missing. Corroded mesh Gabion mesh shows corrosion through more than ¼ of its gage. All gabion mesh capable of containing rock and retaining designed form. Collapsed or deformed baskets Gabion basket shape deformed due to any cause. All gabion baskets intact, structure stands as designed. Missing rock Any rock missing that could cause gabion to loose structural integrity. No rock missing. Manhole/Chamber Worn or damaged post, baffles or side of chamber Structure dissipating flow deteriorates to ½ or original size or any concentrated worn spot exceeding one square foot which would make structure unsound. Structure is in no danger of failing. Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch or any evidence of soil entering the structure through cracks, or maintenance inspection personnel determines that the structure is not structurally sound. Manhole/chamber is sealed and structurally sound. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No soil or water enters and no water discharges at the joint of inlet/outlet pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-15 NO. 9 – FENCING MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Erosion or holes under fence Erosion or holes more than 4 inches high and 12-18 inches wide permitting access through an opening under a fence. No access under the fence. Wood Posts, Boards and Cross Members Missing or damaged parts Missing or broken boards, post out of plumb by more than 6 inches or cross members broken No gaps on fence due to missing or broken boards, post plumb to within 1½ inches, cross members sound. Weakened by rotting or insects Any part showing structural deterioration due to rotting or insect damage All parts of fence are structurally sound. Damaged or failed post foundation Concrete or metal attachments deteriorated or unable to support posts. Post foundation capable of supporting posts even in strong wind. Metal Posts, Rails and Fabric Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1½ inches. 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 fabric) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or protective coating Part or parts that have a rusting or scaling condition that has affected structural adequacy. Structurally adequate posts or parts with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-16 NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Chain Link Fencing Gate Damaged or missing members Missing gate. Gates in place. Broken or missing hinges such that gate cannot be easily opened and closed by a maintenance person. Hinges intact and lubed. Gate is working freely. Gate is out of plumb more than 6 inches and more than 1 foot out of design alignment. Gate is aligned and vertical. Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in place. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. Bar Gate Damaged or missing cross bar Cross bar does not swing open or closed, is missing or is bent to where it does not prevent vehicle access. Cross bar swings fully open and closed and prevents vehicle access. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Support post damaged Support post does not hold cross bar up. Cross bar held up preventing vehicle access into facility. Bollards Damaged or missing bollards Bollard broken, missing, does not fit into support hole or hinge broken or missing. No access for motorized vehicles to get into facility. Bollards do not lock Locking assembly or lock missing or cannot be attached to lock bollard in place. No access for motorized vehicles to get into facility. Boulders Dislodged boulders Boulders not located to prevent motorized vehicle access. No access for motorized vehicles to get into facility. Evidence of vehicles circumventing boulders Motorized vehicles going around or between boulders. No access for motorized vehicles to get into facility. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-17 NO. 11 – GROUNDS (LANDSCAPING) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot 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. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard tree identified Any tree or limb of a tree identified as having a 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. No hazard trees in facility. Damaged tree or shrub identified Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-18 NO. 12 – ACCESS ROADS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet (i.e., trash and debris would fill up one standards size garbage can). Roadway drivable by maintenance vehicles. Debris which could damage vehicle tires or prohibit use of road. Roadway drivable by maintenance vehicles. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of 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 road surface to less than 14 feet. Roadway overhead clear to 14 feet high. Any obstruction restricting the access to a 10- to 12 foot width for a distance of more than 12 feet or any point restricting access to less than a 10 foot width. At least 12-foot of width on access road. Road Surface Erosion, settlement, potholes, soft spots, ruts Any surface defect which hinders or prevents maintenance access. Road drivable by maintenance vehicles. Vegetation on road surface Trees or other vegetation prevent access to facility by maintenance vehicles. Maintenance vehicles can access facility. Shoulders and Ditches Erosion Erosion within 1 foot of the roadway more than 8 inches wide and 6 inches deep. Shoulder free of erosion and matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or hinder maintenance access. Weeds and brush cut to 2 inches in height or cleared in such a way as to allow maintenance access. Modular Grid Pavement Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing blocks/grids Access surface compacted because of broken on missing modular block. Access road surface restored so road infiltrates. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-19 NO. 13 – BASIC BIOSWALE (GRASS) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and/or debris accumulated on the bioswale site. No trash or debris on the bioswale site. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Swale Section Sediment accumulation Sediment depth exceeds 2 inches in 10% of the swale treatment area. No sediment deposits in grass treatment area of the bioswale. Sediment inhibits grass growth over 10% of swale length. Grass growth not inhibited by sediment. Sediment inhibits even spreading of flow. Flow spreads evenly through swale Erosion/scouring Eroded or scoured swale bottom due to channelization or high flows. No eroded or scoured areas in bioswale. Cause of erosion or scour addressed. Poor vegetation coverage Grass is sparse or bare or eroded patches occur in more than 10% of the swale bottom. Swale has no bare spots and grass is thick and healthy. Excessive vegetation growth Grass excessively tall (greater than 10 inches), grass is thin or nuisance weeds and other vegetation have taken over. Grass is between 3 and 4 inches tall, thick and healthy. No nuisance vegetation present. Excessive shade Grass growth is poor because sunlight does not reach swale. Healthy grass growth or swale converted to a wet bioswale. Constant baseflow Continuous flow through the swale, even when it has been dry for weeks or an eroded, muddy channel has formed in the swale bottom. Baseflow removed from swale by a low- flow pea-gravel drain or bypassed around the swale. Standing water Water pools in the swale between storms or does not drain freely. Swale freely drains and there is no standing water in swale between storms. Channelization Flow concentrates and erodes channel through swale. No flow channels in swale. Flow Spreader Concentrated flow Flow from spreader not uniformly distributed across entire swale width. Flows are spread evenly over entire swale width. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-22 NO. 16 – WETPOND MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris accumulated on the wetpond site. Wetpond site free of any trash or debris. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Side Slopes of Dam, Berm, internal berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of dams, berms or slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are 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. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Top or Side Slopes of Dam, Berm, internal berm or Embankment Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Irregular surface on internal berm Top of berm not uniform and level. Top of berm graded to design elevation. Pond Areas Sediment accumulation (except first wetpool cell) Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth. Sediment accumulation (first wetpool cell) Sediment accumulations in pond bottom that exceeds the depth of sediment storage (1 foot) plus 6 inches. Sediment storage contains no sediment. Liner damaged (If applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Low water level (all wetpool cells) Cell level(s) drops more than 12 inches in any 7-day period. Cell level(s) drops less than 12 inches in any 7-day period. Algae mats (first wetpool cell) Algae mats develop over more than 10% of the water surface should be removed. Algae mats removed (usually in the late summer before Fall rains, especially in Sensitive Lake Protection Areas.) APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-23 NO. 16 – WETPOND MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pond Areas (cont.) Sparse or dying design planting and poor vegetation survival Sparse or dying design planting, or when design plantings are not thriving across 80% or more of the design vegetated areas within the pond; invasive vegetation (e.g., cattails) Design plantings and vegetation are thriving and appropriately spaced across 80% or more of the design vegetated areas within the pond; invasives removed including root clumps 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 Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. Rock missing Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. Spillway restored to design standards. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-48 NO. 39 – RETAINED TREES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Tree Dead or declining Dead, damaged, or declining Tree replaced per planting plan or acceptable substitute NO. 40 – FILTERRA SYSTEM MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED In addition to the specific maintenance criteria provided below, all manufacturer’s requirements shall be followed. Facility – General Requirements Life cycle Once per year, except mulch and trash removal twice per year Facility is re-inspected and any needed maintenance performed Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries, or paint Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet Excessive sediment or trash accumulation Accumulated sediments or trash impair free flow of water into system Inlet should be free of obstructions allowing free distributed flow of water into system Mulch Cover Trash and floatable debris accumulation Excessive trash and/or debris accumulation Minimal trash or other debris on mulch cover. Mulch cover raked level. “Ponding” of water on mulch cover “Ponding” in unit could be indicative of clogging due to excessive fine sediment accumulation or spill of petroleum oils Stormwater should drain freely and evenly through mulch cover Proprietary Filter Media/ Vegetation Substrate “Ponding” of water on mulch cover after mulch cover has been maintained Excessive fine sediment passes the mulch cover and clogs the filter media/vegetative substrate Stormwater should drain freely and evenly through mulch cover. Replace substrate and vegetation when needed Vegetation Plants not growing or in poor condition Soil/mulch too wet, evidence of spill, incorrect plant selection, pest infestation, and/or vandalism to plants Plants should be healthy and pest free Media/mulch too dry Irrigation is required Plants absent Plants absent Appropriate plants are present Excessive plant growth Excessive plant growth inhibits facility function or becomes a hazard for pedestrian and vehicular circulation and safety Pruning and/or thinning vegetation maintains proper plant density. Appropriate plants are present. Structure Structure has visible cracks Cracks wider than ½ inch Evidence of soil particles entering the structure through the cracks Structure is sealed and structurally sound