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HomeMy WebLinkAboutTIR-4035 Technical Information Report Talbot Substation Stormwater Support Puget Sound Energy Renton, Washington April 17, 2017 This page intentionally left blank. This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | i Contents 1 Project Overview ................................................................................................................................. 1 1.1 Existing Conditions .................................................................................................................... 1 1.2 Proposed Conditions ................................................................................................................. 2 2 Conditions and Requirements Summary ............................................................................................ 2 3 Offsite Analysis .................................................................................................................................... 4 4 Flow Control and Water Quality Facility Analysis and Design ............................................................ 8 5 Conveyance System Analysis and Design ........................................................................................ 13 6 Special Reports and Studies ............................................................................................................. 13 7 Other Permits .................................................................................................................................... 13 8 CSWPPP Analysis and Design ......................................................................................................... 14 9 Bond Quantities, Facility Summaries, and Declaration of Covenant ................................................ 17 10 Operations and Maintenance Manual ............................................................................................... 17 11 References ........................................................................................................................................ 17 Tables Table 1: Existing Condition Acreage and Peak Flow Values ........................................................................ 8 Table 2: Proposed Condition Acreage and Peak Flow Values ..................................................................... 9 Table 3: Existing and Proposed Land Use Summary ................................................................................. 10 Table 4: Pre-developed and Proposed Controlled Flow Comparison ........................................................ 12 Table 5: Additional Project Permit Requirements ....................................................................................... 14 Figures Figure 1: TIR Worksheet Figure 2: Site Location Figure 3: Drainage Basins, Subbasins, and Site Characteristics Figure 4: Soils Figure 5: Flow Chart for Determining Type of Drainage Review Required Figure 6: Offsite Analysis Figure 7: Existing Hydrology Figure 8: Proposed Hydrology Figure 9: Flow Chart for Determining Individual Lot BMP Requirements of the SWDM Figure 10: Pond Sketch Technical Information Report Talbot Substation Stormwater Support ii | November 16, 2016 Appendices Appendix A: Firmette Appendix B: Drainage System Table Appendix C: Site Photos Appendix D: Reference 11-A Flow Control Areas Appendix E: Stormwater Model Output Appendix F: Construction Stormwater Pollution Prevention Plan Appendix G: Facility Summaries and Declaration of Covenant Appendix H: Operations and Maintenance Manual Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 1 1 Project Overview Puget Sound Energy (PSE) is proposing a series of improvements at their Talbot Substation located in Renton, Washington. A copy of the TIR Worksheet (Figure 1) is located below. Figure 2 below shows the site location and adjacent critical areas. Proposed improvements will occur on the eastern side of the substation (referred to as the project area), and will include the installation of foundations, security perimeter fence, landscape screening, paving of a small portion of the access road, installation of a new stormwater drainage and flow control system, road maintenance, and on-site oil spill control best management practices (BMPs). The extent of disturbance will be approximately 5.89 acres. Approximately 4.17 acres will consist of gravel road and surface improvements. Another 1.22 acres will be for the installation of new foundations and Spill Prevention, Control, and Countermeasures (SPCC) structures. The remaining 0.5 acres will be for installation of a stormwater detention pond. The existing site contains electrical structures, and yard rock covers the ground surface. The existing and proposed conditions as well as the site constraints are described below. 1.1 Existing Conditions 1.1.1 Topography The Talbot substation covers approximately 7.75 acres between Beacon Way South, South Puget Drive, and Grant Ave South in Renton, W ashington, as shown in Figure 2. The site is located near the top of a ridge and is primarily accessed from South Puget Drive, which ties into a gravel driveway leading to the site. The topography inside the substation slopes slightly away from the center to promote drainage away from electrical equipment. The existing grade outside the substation fence generally slopes away from the substation except on the eastern and northwestern sides where there is elevated terrain. 1.1.2 Drainage In general stormwater runoff flows outwards from the middle of the substation. Existing drainage pipes on the northeast and southeast sides of the substation are tied to catch basins within the fence line whose rims are slightly raised above the yard rock, preventing them from capturing flow. The perimeter path on the northeastern side of the substation is higher than the existing grade within the fence line, preventing flow from draining off the site along this edge. An elevated field along the eastern edge of the site prevents drainage away from the substation on this side. Runoff along the northeastern, eastern, and southeastern sides of the substation therefore tends to pond within the substation and infiltrate. Along the southern edge of the substation, runoff is able to flow south across the southern perimeter path and into a depression located between the substation and access road. This route presents the path of least resistance for stormwater. The depression is drained by a culvert beneath the access road to a second depression which drains eastwards, towards Grant Avenue South. Existing drainage patterns are shown in Figure 3. Existing soil types can be found on Figure 4. KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual 1/9/2009 KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 1 Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner ________________________ Phone ______________________________ Address ____________________________ ____________________________________ Project Engineer ______________________ Company ___________________________ Phone ______________________________ Project Name _________________________ DDES Permit # ________________________ Location Township ______________ Range ________________ Section ________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS ‰ Landuse Services Subdivison / Short Subd. / UPD ‰ Building Services M/F / Commerical / SFR ‰ Clearing and Grading ‰ Right-of-Way Use ‰ Other _______________________ ‰ DFW HPA ‰ COE 404 ‰ DOE Dam Safety ‰ FEMA Floodplain ‰ COE Wetlands ‰ Other ________ ‰ Shoreline Management ‰ Structural Rockery/Vault/_____ ‰ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (circle): Date (include revision dates): Date of Final: Full / Targeted / Large Site ___________________ ___________________ ___________________ Type (circle one): Date (include revision dates): Date of Final: Full / Modified / Small Site __________________ __________________ __________________ Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Date of Approval: ______________________ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 2 Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ _________________________________________ _________________________________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan : _________________________________ Special District Overlays: __________________________________________________________ Drainage Basin: ___________________________________ Stormwater Requirements: ________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS ‰ River/Stream _______________________ ‰ Lake _____________________________ ‰ Wetlands ___________________________ ‰ Closed Depression ___________________ ‰ Floodplain __________________________ ‰ Other ______________________________ ___________________________________ ‰ Steep Slope ______________________ ‰ Erosion Hazard ___________________ ‰ Landslide Hazard __________________ ‰ Coal Mine Hazard __________________ ‰ Seismic Hazard ___________________ ‰ Habitat Protection __________________ ‰ _________________________________ Part 10 SOILS Soil Type _________________ _________________ _________________ _________________ Slopes _________________ _________________ _________________ _________________ Erosion Potential _________________ _________________ _________________ _________________ ‰ High Groundwater Table (within 5 feet) ‰ Other ________________________ ‰ Sole Source Aquifer ‰ Seeps/Springs ‰ Additional Sheets Attached KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 3 Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE ‰ Core 2 – Offsite Analysis_________________ ‰ Sensitive/Critical Areas___________________ ‰ SEPA________________________________ ‰ Other_________________________________ ‰ _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ ‰ Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply) Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (incl. facility summary sheet) Level: 1 / 2 / 3 or Exemption Number ____________ Small Site BMPs ___________________________________ Conveyance System Spill containment located at: _________________________ Erosion and Sediment Control ESC Site Supervisor: 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 (include facility summary sheet) Type: Basic / Sens. Lake / Enhanced Basicm / Bog or Exemption No. ______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): ______________ Datum: Flood Protection Facilities Describe: Source Control (comm./industrial landuse) Describe landuse: Describe any structural controls: KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 4 Oil Control High-use Site: Yes / No Treatment BMP: ________________________________ Maintenance Agreement: Yes / No with whom? ____________________________________ Other Drainage Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION ‰ Clearing Limits ‰ Cover Measures ‰ Perimeter Protection ‰ Traffic Area Stabilization ‰ Sediment Retention ‰ Surface Water Collection ‰ Dewatering Control ‰ Dust Control ‰ Flow Control MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION ‰ Stabilize Exposed Surfaces ‰ Remove and Restore Temporary ESC Facilities ‰ Clean and Remove All Silt and Debris, Ensure Operation of Permanent Facilities ‰ Flag Limits of SAO and open space preservation areas ‰ Other ______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description ‰ Detention ‰ Infiltration ‰ Regional Facility ‰ Shared Facility ‰ Flow Control BMPs ‰ Other ________________ ________________ ________________ ________________ ________________ ________________ ‰ Biofiltration ‰ Wetpool ‰ Media Filtration ‰ Oil Control ‰ Spill Control ‰ Flow Control BMPs ‰ Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 5 Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS ‰ Drainage Easement ‰ Covenant ‰ Native Growth Protection Covenant ‰ Tract ‰ Other ‰ Cast in Place Vault ‰ Retaining Wall ‰ Rockery > 4’ High ‰ Structural on Steep Slope ‰ Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Signed/Date This page intentionally left blank. Talbot Substation Thunder Hills Creek Ginger Creek SE ROYAL HILLS DRSE 19TH STROLLING HILLS AVE SESE 18TH PL SE 16TH PL 116TH AVE SES E 8 T H D R JONES DR SEGRANT AVE SPUGET DR SESE 8TH PL CEDAR RIDGE DR SE PATH: G:\PROJEC TS\WAS HINGTON\PUGET_SOUND_EN ERGY_00 702 2\TAL BOT_STORMWATER_SUPPORT_2699 66\MAP_DOCS \DRAF T\T IR FIGURES\FIGURE_2 _SITE_LOCATION.MXD - USER: TAHOFFMA - DAT E: 11 /1 6/2 016 TALBOT STORMWATER SUPPORT FIGURE 2 SITE LOCATION STORMWATER TIR 0 500Feet O DATA SOURCE: City of Renton,King County (2016) LEGEND Project Are a Roads Streams Coa lmineHazardArea Wetlan ds Landslide Hazard Steep Slo pes Project Location SR-520 I-90 I-405 I-405 I-5 I-5 SR-167 Longe st Proposed Flow path toFlow Control Facility: 630 feet Ex isting a nd ProposedDischarge Point 440 430 420 410 4304204604504 2 0410 410400420410410430 440 460450450 4 4 0 4 4 0 440440 420400 400460 4 4 0 430 4 2 0 410 Project Are aSubbasin:5.89 Acres LocalizedDepression LocalizedDepression LocalizedDepression PATH: G:\PROJEC TS\WAS HINGTON\PUGET_SOUND_EN ERGY_00 702 2\TAL BOT_STORMWATER_SUPPORT_2699 66\MAP_DOCS \DRAF T\T IR FIGURES\FIGURE_3 _DRAINAGE.MX D - USER: TAHOF FMA - DATE: 11/16 /20 16 TALBOT STORMWATER SUPPORT FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CH ARACTERISTICS STORMWATER TIR 0 250Feet O DATA SOURCE: City of Renton,King County (2016) LEGEND Project Are a Con to urs - 10 ft In te rval Existin gFlow Pa th Propo sedFlow Pa th Existin gDrainageInfrastructur e Propo sedDrainageInfrastructur e Propo sedDetention Pond Pond ed Wa terObserved Dur ingField Visit ROLLINGHILLSAVE SE LINCOLNCT SEBLAINE CT SEABERDEENCT SESE 16TH PL PUGET DR SEGRANT AVE SAgD AmC AgC InC BeD PATH: G:\PROJECTS\WAS HINGTON\PUGET_SOUND_E NERGY_00 702 2\TALBOT_STORMWATER_SUPPORT_269 966\MAP_DOCS\DR AFT\TIR FIGURES\FIGURE_4 _SOILS.MXD - USER: TAHOFFMA - DAT E: 11 /1 6/2016 TALBOT STOMWATER SUPPORT FIGURE 4 SOILS STORMWATER TIR 0 190Feet O DATA SOURCE: USDA Web Soil Survey,King County LEGEND Project Area Soil Group Roads This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support 2 | November 16, 2016 1.2 Proposed Conditions Proposed conditions will include a re-graded gravel surface within the substation (approximately 3.43 acres), additional SPCC structures and equipment foundations (approximately 1.22 acres), re-grading of gravel and asphalt roads (approximately 0.74 acres), and the addition of a pond for flow control (approximately 0.5 acres). The proposed conditions will increase impervious area at the site by approximately 15%. This percentage is primarily due to the addition of the SPCC structures and equipment foundations, as well as asphalt entries to the gravel access driveways. Yard rock surfaces will only be replaced or re-graded, they will not be added. The gravel surface inside the fence line of the substation will be re-graded to smooth any slight depressions in the gravel, promote flow to catch basins, and subsequently limit ponding around electrical equipment and structures. The proposed improvements will not significantly modify the grade of the existing substation or access roads. The impervious SPCC structures and equipment foundations will be added within the substation fence. The asphalt surface will be added at the intersection of the gravel access way and South Puget Drive. Drainage improvements include a new stormwater conveyance network inside the substation which will route flows to a 75,000 cubic foot stormwater detention pond located along the southeastern edge of the substation. This pond will discharge to a depression on the southern side of the existing access road, where flow will resume the existing drainage path towards Grant Avenue South. Proposed drainage facilities can be found on Figure 3. Landscape screening will be installed along the southwest side of the substation property border and the perimeter of the pond. Landscaping will replace non-native plant cover such as blackberry shrubs and non-native grasses. 2 Conditions and Requirements Summary The project is subject to the City of Renton Amendments to the 2009 King County Surface Water Design Manual (KCSWDM), as well as the City of Renton Municipal Code. According to Section 1.1.1 of the City of Renton Amendments to the KCSWDM (COR SWDM), projects resulting in 2,000 square feet or more of new impervious surface, replaced impervious surface, or new plus impervious surface, or 7,000 square feet or more of land disturbing activity require a Drainage Review. Additionally, per Section 1.1.2 of the COR SWDM projects which result in greater than 2,000 square feet of new impervious surface and greater than 35,000 square feet of pervious surface are required to perform a Full Drainage Review. Figure 5 contains the Flow Chart for Determining Type of Drainage Review Required and shows that the project requires a Full Drainage Review. Projects undergoing a Full Drainage Review must meet the Core Requirements and Special Requirements contained in the COR SWDM. These requirements are broken down and discussed in greater detail below. Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 3 2.1 Core Requirement #1: Discharge at the Natural Location Proposed projects must discharge runoff at the natural location and comply with the discharge requirements of Core Requirement #1. The proposed stormwater detention pond which collects runoff from the conveyance system within the substation discharges to the natural discharge location, as shown on Figure 3. Per the discharge requirements of Core Requirement # 1, if the proposed 100-year flow event peak discharge is greater than 0.5 CFS a conveyance system must be provided to convey concentrated runoff to an acceptable discharge point (COR SWDM, 2009). The 100-year peak flow event for the proposed project is larger than 0.5 CFS, and will be routed through the proposed conveyance system and stormwater detention pond to the natural discharge location. The proposed stormwater detention pond will control stormwater flows generated by the substation and discharge at a rate that meets the flow control regulatory requirements. 2.2 Core Requirement #2: Offsite Analysis Core Requirement #2 is discussed in detail in Section 3 of this report. 2.3 Core Requirement #3: Flow Control Core Requirement #3 is discussed in detail in Section 4 of this report. 2.4 Core Requirement #4: Conveyance System Core Requirement #4 is discussed in detail in Section 5 of this report. 2.5 Core Requirement #5: Erosion and Sediment Control Core Requirement #5 is discussed in detail in Section 8 of this report. 2.6 Core Requirement #6: Maintenance and Operations Core Requirement #6 is discussed in detail in Section 10 of this report. 2.7 Core Requirement #7: Financial Guarantees and Liability Core Requirement # 7 is discussed in detail in Section 9 of this report. 2.8 Core Requirement #8: Water Quality The project site qualifies for the Surface Area Exemption detailed in Section 1.2.8 of the COR SWDM (City of Renton, 2009). • Less than 5,000 square feet of new PGIS that is not fully dispersed will be added and Technical Information Report Talbot Substation Stormwater Support 4 | November 16, 2016 • less than 5,000 square feet of new plus replaced PGIS that is not fully dispersed will be created as part of a redevelopment project and • less than 35,000 square feet of new PGPS that is not fully dispersed will be added. Because this project adds less than 5,000 square feet of PGIS and less than 35,000 square feet of new PGPS, water quality facilities are not required at the project site. 2.9 Special Requirement #1: Adopted Area Specific Regulations This requirement is not applicable as there are no adopted area specific regulations within the project area. 2.10 Special Requirement #2: Flood Hazard Area Delineation This requirement is not applicable as the project area is not within or adjacent to a mapped FEMA flood hazard area. The FIRMETTE (a web-based software program designed to display mapped FEMA floodplains) for the project area can be found in Appendix A. 2.11 Special Requirement #3: Flood Protection Facilities This requirement is not applicable as the proposed project does not rely on an existing flood protection facility or plan to modify or construct a new flood protection facility. 2.12 Special Requirement #4: Source Controls This requirement is not applicable as the proposed project does not require a commercial building or commercial site development permit. 2.13 Special Requirement #5: Oil Control This requirement is not applicable as the proposed project does not have high use characteristics. It should be noted that Spill Prevention, Containment, and Control (SPCC) facilities will be installed around some electrical components which employ oil. 3 Offsite Analysis A Level 1 Analysis was performed to identify any potential drainage, conveyance, or environmental issues downstream of the site that could be affected by the project and require an additional level of analysis. The Level 1 Analysis consists of a resource review and a field inspection where offsite issues are identified. The resource review provides information regarding large-scale existing issues in the project area prior to a site visit. During the field inspection, evidence of on-site and off-site drainage issues or other Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 5 environmental problems are investigated and reported. The scale of the resource review and the field inspection are defined by the downstream study area. 3.1 Task 1: Study Area The study area and extent of the downstream analysis can be found on Figure 6. The USGS StreamStats application in tandem with existing topographic and stormwater conveyance data were used to define the downstream drainage path leaving the project site. As mentioned in Section 1.1.2 above, stormwater runoff exits the project site via the southern side of the substation, passing beneath the access road and eventually flowing west towards Grant Avenue South. The study area for Task 2 is required to extend 1 mile downstream of the project discharge location per Section 1.2.2.1 of the COR SWDM. The study area is required to extend upstream if backwater or upstream effects are anticipated, however the substations location near the top of a ridge precludes any of these effects. The study area for Tasks 3 through 5 must extend to a point where the proposed project area extends less than 15% of the total tributary drainage area, but not less than one-quarter mile downstream of the project area. StreamStats was used to delineate and calculate the area of the watershed, and then determine at what distance the project area composed less than 15% of the tributary drainage area. This distance was less than the minimum distance, one quarter mile and therefore one quarter mile was used for the extent the study area used in Tasks 3 through 5. 3.2 Task 2: Resource Review The resource review was conducted according to Section 2.3.1.1 of the COR SWDM. Information required to be reviewed includes FEMA Maps, presence of sensitive areas, presence of wetlands, presence of nearby 303d listed waters, soil survey information, adopted basin plans, and offsite analysis reports for other projects. The information obtained during the review is detailed below. Adopted basin plans were not available for the project area as of September 2016. FEMA floodplain information was referenced from the online FEMA Flood Map Service Center. The project site is not located within a flood hazard area. The FIRMETTE which includes the project area is located in Appendix A. King County iMap data indicates that the project area is located inside a Coal Mine Hazard Area and adjacent to an Erosion Hazard Area. City of Renton GIS data was also analyzed, and shows that environmentally sensitive or critical areas located near the project area include erosion hazard areas and landslide areas (Figure 2). The closest high-risk erosion hazard area is approximately 1,400 ft west/southwest of the site. Moderate hazard landslide areas are present on the south, southwest, and west sides of the project site. The closest high hazard landslide area is approximately 2,000 feet west of the site. The project area will not discharge directly to any erosion or landslide hazard areas. King County iMap data indicates drainage complaints approximately three quarters of a mile west of the project area, adjacent to I-405. The registered complaints were for Technical Information Report Talbot Substation Stormwater Support 6 | November 16, 2016 garbage dumping. The stormwater discharge from the proposed project area should not have an effect. Sensitive surface waters reviewed included wetlands and impaired waters. City of Renton Wetland Inventory maps for the area do not show wetlands within one mile downstream of the site. Additionally, following a review of the Department of Ecology’s 303d list of impaired waters, no impaired waters were found within one mile downstream of the site. Seven borings were performed as part of a geotechnical study at the project area. Five of the borings were performed inside of the substation, and these discovered several feet of fill soils overlaying seven to twenty-three feet of glacial till. In the area of the proposed stormwater detention pond, two borings were performed which discovered several feet of loose sand and organic topsoil overlaying glacial till. Advance outwash deposits were found below the till soils in all boring samples. No groundwater was encountered at the project site (GeoEngineers, 2016). King County iMap does not identify any stormwater quality problems within the study area. No Basin Plans or Basin Reconnaissance Summary Reports were found for surface waters downstream of the project site, and no nearby offsite analysis reports were obtained as of September 2016 from the City of Renton Development Services Division. Existing and potential problems identified above have been tabulated in the Drainage System Table, located in Appendix B. 3.3 Task 3 through 5: Field Inspection & Results The field inspection was conducted on January 18th, 2016 at the project area and the study area within ¼ mile downstream of the site. The inspection focused on areas identified in the resource review and in previous site visits, such as steep slopes and erosion hazard areas. The purpose of the inspection was to note any erosion or sedimentation, evidence of recurrent flooding, conveyance system issues, or other drainage issues present, as well as observe existing site conditions and verify the tributary drainage basin of the project site. Site photos taken during the visit are found in Appendix C. It is important to note that the field inspection took place following 0.92 inches of rainfall in the two days prior to the visit, so wet weather conditions were observed. Land use immediately adjacent to the site is primarily undeveloped. Areas to the east and west of the substation consist of tall grasses with interspersed shrubs, and the area south of the site consists of moderate to dense trees and shrubs. Grasses surround the north side of the site, with moderate to dense tree and shrub cover north of the grassy areas. The closest developed area downstream of the site is a residential development approximately 400 feet south of the site. A park lies between the residential development and the substation, and consists of lawn grass and some taller grasses around the border. South of the park is more undeveloped grassy and forested area, with a maintained mountain bike trail in the forested area. A small stream or channel was observed crossing the trail via a culvert. The stream appeared to end in the grass area to Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 7 the southwest where it converted to overland flow or infiltrated. No erosion or scour problems were identified in this area. To the east of the project area, the grade gradually slopes upward towards a ridge between the substation and Beacon Way South (gravel road). South of the project area and to the west of the gravel access road the topography is relatively flat. A slight depression is present east of the access road which extends beyond the SE corner of the substation. The west side of the substation is bounded by an approximately 10-ft wide flat area and small ridge. West of the ridge, the grade becomes much steeper. Runoff from the substation is constrained from reaching the steep slope by the ridge feature. The ridge ends just before the southwest corner of the site, where a steep access path leads southwest towards a transmission line tower. To the north of the substation is relatively flat ground with areas of ponding. One depression is present near the NE corner of the site. Two small ponded areas are present along the north edge of the site. No outlets were observed from the ponded areas. Topography downstream of the site consists of gradual slopes across a park and moderate slopes to the west and southwest through forested and grassy areas. A gravel access road intersects an undeveloped area between the park and the substation and leads to a low area south of the road near the tower at the southwest corner of the substation. The low area was identified as an additional area that would likely capture runoff from the substation. The access road continues over a small ridge. Runoff that escaped the low area would enter a forested section crisscrossed with mountain bike paths. Many small depressions were observed along the mountain bike paths. Further downstream is a grassy area west of the park. Moderate slopes continue across the grassy area to Grant Avenue South, approximately ¼ mile downstream of the site. Despite the steep slopes and paths on the west and south sides of the site, no rills or signs of erosion or sedimentation were present during the field inspection of on-site and off-site areas. Additionally, no evidence of recurrent flooding was present in the area. Ponded areas were small, no overtopping of those areas was apparent, and water levels were fairly low within the depressions despite the recent precipitation. These observations suggest that the on-site and off-site areas do not suffer from erosion or flooding drainage problems which could warrant additional flow control for the project. Conveyance observed off-site in the downstream drainage path during the inspection included two culverts. The outlet of a 4” PVC culvert was observed in a depression on the south side of the site between the access road and substation. No water was flowing in the culvert during the time of the inspection. The second culvert (4” PVC) was observed with flow present underneath a section of the mountain bike trail southwest of the site (Figure 6). About 200 feet downstream of the culvert, the flow converted into overland flow through a grassy area. No flooding or erosion issues were observed around the culvert. Based on the observations made during the field inspection, no downstream drainage problems - such as conveyance, flooding, or erosion issues - could be identified for the project area or downstream drainage path within ¼ mile of the project area. Field observations also verified the drainage basin delineation discussed in Section 1. The lack of downstream drainage problems confirms that a Level 1 Analysis is sufficient for the study area. SECTION 1.1 DRAINAGE REVIEW City of Renton 2009 Surface Water Design Manual Amendment 1-10 FIGURE 1.1.2.A FLOW CHART FOR DETERMINING TYPE OF DRAINAGE REVIEW REQUIRED Is the project a single family residential project that results in ≥2,000 sf of new and/or replaced impervious surface or ≥7,000 sf of land disturbing activity, AND meets the following criteria? • The project results in ≤5,000 sf of new impervious surface, and ≤35,000 sf of new pervious surface Yes SMALL PROJECT DRAINAGE REVIEW Section 1.1.2.1 Note: The project may also be subject to Targeted Drainage Review as determined below. No Does the new or redevelopment project result in ≥2,000 sf of new and/or replaced impervious surface or ≥35,000 sf of new pervious surface? No Does the project have the characteristics of one or more of the following categories of projects (see more detailed threshold language on p. 1-13)? 1. Projects containing or adjacent to a flood, erosion, or steep slope hazard area or documented drainage problem; projects within a landslide hazard area or landslide hazard drainage area; or projects that propose ≥7,000 sf (1 ac if project is in Small Project Drainage Review) of land disturbing activity. 2. Projects proposing to construct or modify a drainage pipe/ditch that is 12" or larger or receives runoff from a 12" or larger drainage pipe/ditch. Yes No Yes Reassess whether drainage review is required per Section 1.1.1 (p. 1-8). TARGETED DRAINAGE REVIEW Section 1.1.2.2 Does the project result in ≥50 acres of new impervious surface within a subbasin or multiple subbasins that are hydraulically connected? No FULL DRAINAGE REVIEW Section 1.1.2.3 Yes LARGE PROJECT DRAINAGE REVIEW Section 1.1.2.4 This page intentionally left blank. PATH: G:\PROJECTS\WAS HINGTON\PUGET_SOUND_E NERGY_00 702 2\TALBOT_STORMWATER_SUPPORT_269 966\MAP_DOCS\DR AFT\TIR FIGURES\FIGURE_6 _OFFS ITE _ANALYSIS.MXD - USER: TAHOF FMA - DATE: 11/16/20 16 TALBOT STORMWATER SUPPORT FIGURE 6 OFFSITE ANALYSIS STORMWATER TIR 0 530Feet O LEGEND Project Area Task 2 Study Area Task 3, 4, and 5 Study Are a ParcelBoundary Contours - 10 ft Interval ApproximateDrainage Path Wetland Hazard Area Steep Slope Erosion Landslide Duwamish - Green River Watershed Note: Task 2 Study Area Includes the Downsteram Flow Path 1 Mile Downstre am o f th e Project Are aTasks 3 through 5 Project Area Includes the Downstream Flow Path 1 /4 Mile Do wnstre am of the Proje ct Area This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support 8 | November 16, 2016 4 Flow Control and Water Quality Facility Analysis and Design 4.1 Existing Site Hydrology The existing condition hydrologic analysis assumed that stormwater runoff within the project area was confined to one subbasin which drains to the depression located on the southwestern corner of the project area. Drainage characteristics of the site are discussed in greater detail in Section 1.1.2 of this report. Subbasin area and drainage characteristics can be seen on Figure 7. Existing land cover is primarily yard rock with electrical equipment foundations throughout the site. Existing hydrology was calculated based on a pre-developed forested condition as the project area is located within a designated Flow Control Area per Reference 11-A of the COR SWDM (Appendix D). Existing condition peak flow values were calculated using the KCRTS modeling software. Existing acreage input to the KCRTS model and model results can be found in Table 1, below. Table 1: Existing Condition Acreage and Peak Flow Values Pre-Developed Till Forested Condition Area 5.89 Acres Peak Flow Event Discharge (CFS)* 2- Year 0.16 5-Year 0.28 10-Year 0.29 25-Year 0.37 50-Year 0.44 100-Year 0.48 *Additional KCRTS flow output can be found in Appendix E. 4.2 Proposed Site Hydrology Changes to the existing land cover include removal of existing electrical equipment and the addition of new concrete equipment foundations, placement of new yard rock within the facility, and addition of a new stormwater detention pond (Figure 8). The yard rock is considered a partially impervious surface while all other improvements are considered impervious surfaces. Per Table 3.2.2.E in the 2009 KCSWDM, yard rock (gravel) surfaces must be multiplied by an effective impervious fraction of 0.50 to determine the impervious percentage of yard rock (gravel) surfaces. The remaining fraction is considered pervious. This page intentionally left blank. 380375370355 35034 53403 3 533 0325320315310305285280385 3 6 53 60300295 4204004 0 539 5390290 4 3 5 430 425 4 4 5 440430425 46 5460455450440435 415 4 1 0435430 420 4 1 5 4 1 5 410405400405400 4204 2 0440295 4 6 0 455 450 450 450440440 4 4 0 4 4 0 440 4 3 0 425415 4154054054 0 0 4 0 0 4 0 0395 280460ROLLINGHILLSAVE SE LINCOLNCT SEBLAINE CT SEABERDEENCT SESE 16TH PL PUGET DR SEGRANT AVE SProject Area Subbasin:5.89 Acres LocalizedDepression LocalizedDepression LocalizedDepression 8" CMP Culvert 8" CMP Culvert 12" CMP Culvert 4" Culvert 4" Culvert PATH: G:\PROJECTS\WAS HINGTON\PUGET_SOUND_E NERGY_00 702 2\TALBOT_STORMWATER_SUPPORT_269 966\MAP_DOCS\DR AFT\TIR FIGURES\SITE_H YDROLOGY.MXD - USER : TAHOFFMA - DATE: 11/1 6/201 6 TALBOT STORMWATER SUPPORT FIGURE 7 EXISTING SITE HYDROLOGY STORMWATER TIR 0 200Feet O LEGEND Project AreaSubbasin Boundary Contours - 5 ft Interval Ponded Water Observe dDuring Field Visit DrainageInfrastructure ApproximateDrainage Path Drainage Path Roads This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 9 Proposed condition peak flow values were calculated using the KCRTS modeling software. Proposed acreage input to the KCRTS model and model results can be found in Table 2 below. Table 2: Proposed Condition Acreage and Peak Flow Values Proposed Condition Impervious Area 3.83 Acres Proposed Condition Till Grass Area 2.06 Acres Total Area 5.89 Acres Peak Flow Event Discharge (CFS)* 2- Year 1.11 5-Year 1.20 10-Year 1.34 25-Year 1.44 50-Year 1.98 100-Year 2.25 *Additional KCRTS flow output can be found in Appendix E. 4.3 Performance Standards The project area is located within a designated Flow Control Area per Reference 11-A of the COR SWDM (Appendix D) and is subject to the Flow Control Duration Standard for forested conditions. No drainage problems have been identified within the limits of the offsite analysis (discussed in detail in Section 3), so proposed conditions must match the flow durations for pre-developed, forested rates over the range of flows from 50% of the 2-year up to the full 50-year per Table 1.2.3.A of the COR SWDM (COR SWDM, 2009). Flow control facilities are required, as the project contains greater than 2,000 square feet of new plus replaced impervious surface. In Flow Control Duration Standard areas, these facilities must mitigate for target surfaces including:  New impervious surface that is not fully dispersed,  New pervious surface that is not fully dispersed,  Replaced impervious surface that is not fully dispersed on a parcel redevelopment project in which the total of new plus replaced impervious surface is 5,000 square feet or more. This page intentionally left blank. 430420405 3903803753703503453403253153103053 0 0 4103953 8 5 3603 553 3 0320 2 9 529 03352854404354 2 5420 450 4 4 5 4 4 0 46 54604404352 8 02 754354 3 0 420 4 1 5 415 4 1 0 405400425400365 430 4554 6 0 4 5 5 440 2954 5 0 450 4 5 0440440 4 4 0 440440430 415 4 2 0415415405 4054004 0 0 4 0 0 4 0 0400395 460400 ROLLINGHILLSAVE SE LINCOLNCT SEBLAINE CT SEABERDEENCT SESE 16TH PL PUGET DR SEGRANT AVE SProject Area Subbasin:5.89 Acres 75,000 CFDetention Pond LocalizedDepression LocalizedDepression 24" Culvert 4" Culvert 4" Culvert PATH: G:\PROJECTS\WAS HINGTON\PUGET_SOUND_E NERGY_00 702 2\TALBOT_STORMWATER_SUPPORT_269 966\MAP_DOCS\DR AFT\TIR FIGURES\SITE_H YDROLOGY.MXD - USER : TAHOFFMA - DATE: 11/1 6/201 6 TALBOT STORMWATER SUPPORT FIGURE 8 PROPOSED SITE HYDROLOGY STORMWATER TIR 0 200Feet O LEGEND Project AreaSubbasin Boundary Contours - 5 ft Interval DrainageInfrastructure ApproximateDrainage Path Drainage Path Roads ProposedDetention Pond This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support 10 | November 16, 2016 Flow control facilities and design are discussed in detail in Section 4.4. The NPGIS and pervious areas in Table 3 reflect the division of area covered by yard rock. Table 3: Existing and Proposed Land Use Summary Impervious Pervious Total NPGIS PGIS Existing 3.33 0.00 2.56 5.89 Proposed 3.83 0.00 2.06 5.89 New 0.50 0.00 0.00 0.50 Replaced 3.33 0.00 2.06 5.39 Percent Impervious 65% Flow control BMPs must be provided to either supplement the flow mitigation provided by flow control facilities or provide flow mitigation where flow control facilities are not required (SWDM, 2009). These BMPs must be selected as directed in Section 5.2 of the SWDM. The proposed project area must meet the large lot high impervious BMP requirements listed in Section 5.2.1.2 of the SWDM as the project area is larger than 22,000 square feet and the impervious surface coverage is greater than 45% of the project area. Figure 5.2.1.A Flow Chart for Determining Individual Lot BMP Requirements of the SWDM is shown in Figure 9 below. SECTION 5.2 FLOW CONTROL BMP REQUIREMENTS 1/9/2009 2009 Surface Water Design Manual 5-12 FIGURE 5.2.1.A FLOW CHART FOR DETERMING INDIVIDUAL LOT BMP REQUIREMENTS Is the project on a site/lot smaller than 22,000 square feet?Is it feasible and applicable to implement full dispersion for the roof area as per Section C.2.1? No further BMPs required. Note: Any proposed connection of roof downspouts to local drainage system must be via perforated pipe connection per Section C.2.11. Is it feasible and applicable to implement full infiltration of the roof runoff as per Section C.2.2? Apply one or more of the following to impervious area >10% of site/lot for site/lot sizes <11,000 sf and > 20% of site/lot for site/lot sizes between 11,000 and 22,000 sf (For projects located in critical aquifer recharge areas these impervious area amounts double): 1. Limited Infiltration (Section C.2.3) 2. Basic Dispersion (Section C.2.4) 3. Rain Garden (Section C.2.5) 4. Permeable Pavement (Section C.2.6) 5. Rainwater Harvesting (Section C.2.7) 6. Vegetated Roof (Section C.2.8) 7. Reduced Impervious Service Credit (Section C.2.9) 8. Native Growth Retention Credit (Section C.2.10) No Yes Yes Yes No Is the project on a site/lot 22,000 square feet or larger with impervious surface coverage of 45% or less? Is it feasible and applicable to implement full dispersion on all target impervious surface as per Section C.2.1? No further BMPs required. Note: Any proposed connection of roof downspouts to local drainage system must be via perforated pipe connection per Section C.2.11. Is it feasible and applicable to implement full infiltration of the roof runoff as per Section C.2.2 or Section 5.4? One or more of the following BMPs must be implemented for that portion of target impervious surface not addressed with full dispersion or with full infiltration of roof runoff: 1. Full Infiltration (Section C.2.2 or Section 5.4) 2. Limited Infiltration (Section C.2.3) 3. Basic Dispersion (Section C.2.4) 4. Rain Garden (Section C.2.5) 5. Permeable Pavement (Section C.2.6) 6. Rainwater Harvesting (Section C.2.7) 7. Vegetated Roof (Section C.2.8) 8. Reduced Impervious Service Credit (Section C.2.9) 9. Native Growth Retention Credit (Section C.2.10) Yes Yes Yes No Is there any remaining target impervious surface not addressed with full dispersion or with full infiltration of roof runoff? No No The project must be a site/lot 22,000 square feet or larger with impervious surface coverage of more than 45%? Is it feasible and applicable to implement full dispersion on all target impervious surface as per Section C.2.1? No further BMPs required. Note: Any proposed connection of roof downspouts to local drainage system must be via perforated pipe connection per Section C.2.11. Projects with impervious area greater than 45% and equal to or less than 65% one or more of the following must be applied to an impervious area greater than or equal to 20% of the site or 40% of the target impervious surface whichever is less OR for projects greater than 65% impervious one or more of the following must be applied to an impervious area greater than or equal to 10% of site or 20% of target impervious surface, whichever is less: 1. Full Infiltration (Section 5.4) 2. Limited Infiltration (Section C.2.3) 3. Basic Dispersion (Section C.2.4) 4. Rain Garden (Section C.2.5) 5. Permeable Pavement (Section C.2.6) 6. Rainwater Harvesting (Section C.2.7) 7. Vegetated Roof (Section C.2.8) 8. Reduced Impervious Service Credit (Section C.2.9) 9. Native Growth Retention Credit (Section C.2.10) No Yes No Yes No Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 11 The following list discusses each flow control BMP and its feasibility at the project area. • Full Infiltration o The project area lies over fill materials which are not suited for infiltration BMPs. • Limited Infiltration o The project area lies over fill materials which are not suited for infiltration BMPs. • Basic Dispersion o Existing topography on the northern and eastern edges of the project area forms high ground and prevents stormwater runoff from exiting the site. These higher areas would also restrict the vegetated flow path of a basic dispersion BMP to several feet, below the acceptable value. The eastern side of the project area is within the substation and bordered by yard rock not suitable for dispersion BMPs as there is no vegetated flow path and discharging stormwater within a substation is not recommended. • Rain Garden o There is no space available within the project area for a rain garden. The projects natural discharge location is located on the southern edge of the project area, and the proposed stormwater detention pond which has been designed to mitigate for all target surfaces within the project area lies in that location. Existing topography surrounding the northern and eastern edges of the site prevents placement of a rain garden in these locations, and a rain garden could not be placed on the western edge of the project area within the substation fence. • Permeable Pavement o No major paving activities are being proposed at the project area. • Rainwater Harvesting o The control house is the only structure with a roof that lies inside the project area. Storage of rainwater associated with a rainwater harvesting facility within the fence line of the substation is not feasible. There is also no use for harvested rainwater at the project site, no plants require irrigation and there are no facilities which may use harvested water. • Vegetated Roof o Vegetated rooftops within substation facilities are not feasible as the required maintenance would involve getting on top of or near the top of the roof surface in close proximity to high voltage power facilities. Technical Information Report Talbot Substation Stormwater Support 12 | November 16, 2016 • Reduced Impervious Surface Credit o Impervious surfaces have been restricted to the maximum extent feasible. Permeable yard rock is being used where vehicle access is not required within the substation fence. Impervious surfaces within the project area include the proposed stormwater detention pond, electrical and SPCC facilities, and the access road required for vehicles. • Native Growth Retention Credit o There are no native growth areas located within the project area. The proposed flow control facility will mitigate for all target surfaces at the project area. Proposed conveyance systems must be designed to convey the 25-year peak flow event with a minimum 6 inches of freeboard to the structure grate. Developed conditions must be assumed for onsite tributary areas, while existing conditions shall be assumed for offsite tributary areas. For events greater than the 25-year peak flow, structures may overtop. However, the 100-year peak flow event may not create or exacerbate any existing severe flooding or erosion problem per Core Requirement #2 of the COR SWDM. All overflows for peak flow events up to and including the 100-year event must discharge to their natural discharge location at the project area. Stormwater water quality treatment facilities are not required at the project area as the total area of pollution-generating surfaces is below the water quality requirement thresholds. SPCC structures will be installed around electrical components requiring oil in order to prevent stormwater contamination in the event an oil spill. These are the only water quality facilities which will be present at the project site. 4.4 Flow Control System An illustrative sketch of the proposed stormwater detention facility can be found below (Figure 10). KCRTS output containing “Compare Flow Duration” files and other model results can be found in Appendix E. While there are landslide hazard areas adjacent to the project, the project is not located within those areas and therefore is not required to use a safety factor when designing the stormwater detention facility (SWDM, 2009). Table 4 below compares the pre-developed condition discharge to the proposed condition site discharge from the flow control facility. Table 4: Pre-developed and Proposed Controlled Flow Comparison Peak Flow Event Discharge (CFS) Existing Proposed from Flow Control Facility 2- Year 0.16 0.09 5-Year 0.28 0.26 10-Year 0.29 0.28 25-Year 0.37 0.36 50-Year 0.44 0.82 100-Year 0.48 1.04 This page intentionally left blank. Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 13 4.5 Water Quality System As mentioned above, stormwater water quality facilities are not required. SPCC facilities will be placed where necessary. 5 Conveyance System Analysis and Design During field observations, two four-inch outlet pipes and catch basins were observed at the project area within the substation fence line at the northern and southern edges of the substation. No further analysis was performed on the existing conveyance system. The proposed stormwater conveyance system was designed to meet the conveyance requirements discussed in Section 4.3 of this report and was analyzed using the Rational Method and XP-SWMM. The Rational Method was used to assess the capacity of the pipes within the conveyance system as required by the 2009 SWDM. XP-SWMM was then used to demonstrate that the pipe system structures contain the hydraulic grade line for the 25-year rainfall event as required by the 2009 SWDM. The Rational Method conservatively calculates runoff flows based on basin area, rainfall intensity, and a runoff coefficient specific to land cover. Runoff flows into each catch basin were calculated for the 25-year event, and a water balance was performed to estimate the flows which would need to be conveyed in each pipe. When the flows were compared to the proposed conveyance system design pipe capacities, all proposed pipes were sized appropriately to convey the 25-year event flows. In XP-SWMM, conveyance system pipes were designed and modeled as 8-inch or 12 inch high density polyethylene (HDPE) pipe or perforated PVC pipe. Catch basins in the conveyance system were either Type 1 or type 1L. The conveyance system was designed to route runoff from the substation, SPCC curb areas, and control house roof toward the south side of the substation, where a pipe outfalls to the proposed detention pond. Slopes of all proposed pipes in the conveyance system were modeled as 0.5%. Compliance with the requirements discussed in Section 4.3 was assessed by routing 25- and 100-year rainfall events through the XP-SWMM model. During the 25-year event, all structures appeared to maintain over 6 inches of freeboard in the model. Additionally, the hydraulic grade line was contained within the conveyance pipes. The conveyance system did not flood during the 100-year event. Model output can be found in Appendix E. 6 Special Reports and Studies No special reports or studies have been prepared for this project. 7 Other Permits Table 5 below lists additional permits required for the project area and their effects on the stormwater design. Technical Information Report Talbot Substation Stormwater Support 14 | November 16, 2016 Table 5: Additional Project Permit Requirements Permit Agency Effects on Stormwater Design TBD TBD TBD TBD TBD TBD 8 CSWPPP Analysis and Design A CSWPPP has been developed for the project and is located in Appendix F. 8.1 ESC Plan Analysis and Design The following ESC best management measures will be employed at the project area, as shown on the TESC plans and discussed in the CSWPPP: 8.1.1 Clearing Limits To protect adjacent properties and reduce the volume of soil exposed to construction, construction limits will be clearly marked where necessary before construction begins. The construction of the proposed stormwater detention pond and paving of a small portion of the existing access road will be the only ground disturbing activity occurring outside of the substation fence. Natural vegetation and topsoil at the project area shall be retained to the maximum extent feasible. High visibility fence and silt fence BMPs will be used around the perimeter of the project area so that disturbance is kept to a minimum outside the work area. 8.1.2 Cover Measures As the project is located west of the Cascade Mountain Crest, no soils shall remain exposed and unworked for more than seven days during the dry season (May 1 to September 30) and two days during the wet season (October 1 to April 30). Between these times, exposed soils stored aboveground shall be protected with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. Regardless of time, all soils shall be stabilized at the end of the shift before a holiday or weekend, and if needed, based on weather forecasts. Any areas expected to remain unworked for greater than 30 days must be seeded or sodded (King County, 1998). During the wet season, soil stockpiles with slopes greater than or equal to 3H:1V, or with over ten feet of vertical relief must be covered if they will remain unworked for over 12 hours. During the wet season sufficient cover materials to stabilize all disturbed areas must be stockpiled on site, and the Wet Season Provisions of Section D.5.S of the King County Erosion and Sediment Control Standards must be followed (King County, 1998). Permanent stabilization will be achieved by placement of yard rock within the substation, and seeding at the proposed stormwater detention pond. 8.1.3 Perimeter Protection Vegetation and slope characteristics vary within the project area. The eastern edge of the project area is elevated and there is no risk contaminated stormwater will exit the project site in that area. The proposed stormwater detention pond and its outlet structure will be installed along the southern edge of the project area. Silt fence will be installed in this area to ensure no contaminated stormwater exits the project area. Silt fencing will Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 15 extend along the existing access road to its intersection with Puget Drive Southeast to prevent sediment generated from the proposed paving activities from exiting the project site. Concrete will be poured on site for proposed electrical equipment foundations within the substation. All concrete at the project area will be handled such that no cementitious material will enter stormwater runoff. Handling procedures are detailed on the TESC plans. 8.1.4 Traffic Area Stabilization The project area will be accessed from the existing access road located on the southern edge of the substation. This access road is a stabilized surface and does not require additional stabilization. Proposed stormwater detention pond construction and access road paving will occur from the existing access road. 8.1.5 Sediment Retention The proposed stormwater detention pond will be retrofitted as a temporary sediment storage facility for the duration of the project. All open grate catch basins and inlets located at the project area will be protected with storm drain inlet protection in order to prevent sediment contamination from entering the conveyance system. The sediment pond must have adequate surface area as defined in Section D.4.5.2 of the King County Erosion and Sediment Control Standards (King County, 1998). Required Pond Surface Area at top of Riser - SA = 2 x Q2/0.00096 Proposed 2-year Peak Flow - Q2= 0.092 Required SA = 192 Square Feet Provided Surface Area: ~ 16,000 Square Feet 8.1.6 Surface Water Collection Outlet protection will be installed at the outlet of the proposed stormwater detention pond before stormwater is routed through the facility. 8.1.7 Dewatering Control Dewatering is not anticipated at the project site, as groundwater was not encountered during field activities performed by GeoEngineers (GeoEngineers, 2016). 8.1.8 Dust Control Wind transport of soils is not anticipated at the project site. Exposed soils will be stabilized and will not remain exposed for long periods. 8.1.9 Flow Control The project area triggers Core Requirement #3: Flow Control. The proposed stormwater detention pond will be retrofitted to serve as a sediment pond during construction. During this period, the hydraulic control structure and pond will continue to function as flow control facility’s and restrict flow rates exiting the site to acceptable limits. Technical Information Report Talbot Substation Stormwater Support 16 | November 16, 2016 8.2 CSWPPP Plan Design The following ESC best management measures will be employed at the project area, as shown on the TESC plans and discussed in the CSWPPP: • High Visibility Plastic Fence o High visibility plastic fence will be used around the perimeter of the substation and access road to clearly mark the proposed limits of construction. This will prevent unnecessary disturbance of existing vegetation and soils. • Silt Fence o Silt fence will be placed along the southern border of the existing access road to prevent sediment contaminated stormwater generated from the construction of the proposed stormwater detention pond and paving of the existing access road from exiting the project site. Silt fence will also serve to delineate the construction limits on the southern boundary of the project area • Temporary Sediment Pond o The proposed stormwater detention pond will be retrofitted as a temporary sediment pond. It will serve to retain sediment generated within the substation fence by placement of the proposed foundations, yard rock, and electrical components. The sediment pond will prevent sediment from exiting the project area. Sediment retention facilities are required whenever the project area exceeds three acres. Flow control is also required for the project, and the proposed stormwater detention pond will continue to regulate outflows through its control structure while it is being used as a temporary sediment retention facility. • Catch Basin Insert o Catch basin inserts will be placed on all catch basins within the substation fence line. They will be used to prevent sediment generated by work within the substation fence line from entering the proposed stormwater conveyance system and being transported downstream. • Outlet Protection o Outlet protection will be used at the outlet of the proposed stormwater detention pond. It will prevent scouring and erosion due to stormwater discharges exiting the pond. This is a permanent BMP which will be retained in place after construction is complete. Updates to the SWPPP may be requested by King County at any time during project construction if the County determines that pollutants generated on the construction site have the potential to contaminate surface, storm, or ground water. Technical Information Report Talbot Substation Stormwater Support November 16, 2016 | 17 9 Bond Quantities, Facility Summaries, and Declaration of Covenant 9.1 Bond Quantities Worksheet The Bond Quantities Worksheet is located in Appendix G. 9.2 Flow Control and Water Quality Facility Summary Sheet and Sketch The Flow Control and Water Quality Facility Summary Sheet and Sketch is located in Appendix G. 9.3 Declaration of Covenant for Privately Maintained Flow Control and WQ Facilities Declaration of Covenant is not required for proposed privately maintained flow control facilities. 9.4 Declaration of Covenant for Privately Maintained Flow Control BMPs There are no flow control BMPs present at the project area. 10 Operations and Maintenance Manual A copy of the Operations and Maintenance Manual, along with the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities is located in Appendix H. 11 References City of Renton. (2010). City of Renton Amendments to the King County Surface Water Design Manual. Renton: City of Renton. King County. (2009). Surface Water Design Manual. Seattle: King County . This page intentionally left blank. Appendix A FEMA Firmette This page intentionally left blank. Appendix B Drainage System Table KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual 1/9/2009 KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-B OFFSITE ANALYSIS DRAINAGE SYSTEM TABLE 1/9/2009 OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Subbasin Name: Subbasin Number: Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from site discharge Existing Problems Potential Problems Observations of field inspector, resource reviewer, or resident see map Type: sheet flow, swale, stream, channel, pipe, pond; Size: diameter, surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % ¼ ml = 1,320 ft. constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion tributary area, likelihood of problem, overflow pathways, potential impacts This page intentionally left blank. Appendix C Site Photographs This page intentionally left blank. Site Photos January 18th, 2016 •Ponded water along eastern edge of site. •Ponded water along northwestern edge of site. •Elevated field located off of the eastern edge of the substation, looking south. •Elevated area along northern edge of substation, looking west. •Culvert outletting from south end of substation into depression. •Local depression along southern edge of substation (site of proposed stormwater detention pond). •Local depression located along substation discharge path off the southwest corner of the substation. •Typical mountain bike path through downstream drainage area. •4” Culvert passing beneath mountain bike path. •Looking south towards Grant Avenue South. •Looking north towards substation, along drainage path. This page intentionally left blank. Appendix D Reference 11-A Flow Control Areas LakeDesire ShadyLake (MudLake) PantherLake LakeYoungs LakeWashington Bl a c kRi ver Gr eenRiv e r C edarRi verUV900 UV167 UV515 UV169 UV900 UV169 UV167BN IncBN IncBBNNIInnccSSEE RReennttoonn IIssss aa qquuaahh RR dd RReennttoonn MMaappllee VVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEESSWW SSuunnsseettBBllvv dd RRaaiinnii eerrAAvveeNNNE 3rd S t NE 3rd S t SW 43rd StSW 43rd St SS EE CCaarrrrRR dd NE 4th StNE 4th St SSEE RReennttoonn MMaappllee VVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNN EE DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 1671144 00tthh WWaayy SS EENNEE 2277tthh SStt 115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St N 8th StN 8th St PP uuggeettDDrrSSEE RR ee nnttoonnAAvvee SS SSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEESE 128th StSE 128th St II nntt eerr uurr bbaannAA vvee SS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeett rr oovvii tt sskkyyRRddEEVVaalllleeyyHHwwyySE 192nd StSE 192nd St SE 60th StSE 60th St TTaallbboottRRddSSRRee nn tt oo nn AAvveeSS116644tthhAAvveeSSEESE 208th StSE 208th St SE 72nd StSE 72nd St RR aaiinniieerr AA vvee SS 111166tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS 118800tthh SStt CCooaall CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St 114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBeeaaccoonn AA vv ee SS FFoorreesstt DDrr SSEE SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEE MMaayy VVaalllleeyy RRdd SS EE JJ oo nn ee ss RR dd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SE 144th StSE 144th St 114488tthhAAvveeSSEE115544tthhPPllSSEELL aa kk ee WWaa sshhii nnggtt oonnBBll vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 ,§-405 µ0 1 2 Miles Flow Control Application Map Reference 11-A Date: 01/09/2014 Flow Control Standards Peak Rate Flow Control Standard (Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) Flow Control Duration Standard (Forested Conditions) Flood Problem Flow Unincorporated King County Flow Control Standards Renton City Limits Potential Annexation Area Project Location Appendix E Stormwater Model Input & Output This page intentionally left blank. KCRTS Pre-developed and Developed Land Use Areas Pre-developed and Developed Land Use Areas Model Input Pre-developed Condition Land Use Areas Land Use Type Area (ac) Impervious 0.00 Till Forest 5.89 Developed Condition Land Use Areas Land Use Type Area (ac) Impervious 3.83 Till Grass 2.06 Total Area: 5.89 KCRTS Pre-developed and Developed Duration Comparison Predeveloped and Developed Duration Comparison Duration Comparison Analysis Base File: psetalbotpredev_020816.tsf New File: pserdout_020816.tsf Fraction of Time Check of Tolerance Cutoff Base New % Change Prob Base New % Change (CFS) 0.081 0.0095 0.0067 -29.5 0.0095 0.081 0.078 -4.6 0.104 0.0063 0.0056 -10.4 0.0063 0.104 0.087 -16.0 0.126 0.0050 0.0053 5.9 0.0050 0.126 0.132 4.4 0.148 0.0037 0.0038 3.1 0.0037 0.148 0.151 1.9 0.171 0.0029 0.0025 -11.9 0.0029 0.171 0.165 -3.4 0.193 0.0022 0.0018 -19.9 0.0022 0.193 0.178 -7.8 0.215 0.0015 0.0011 -23.9 0.0015 0.215 0.202 -6.0 0.237 0.0010 0.0007 -31.7 0.0010 0.237 0.221 -7.0 0.26 0.0006 0.0005 -15.8 0.0006 0.260 0.250 -3.8 0.282 0.0003 0.0004 4.8 0.0003 0.282 0.285 1.2 0.304 0.0002 0.0003 14.3 0.0002 0.304 0.316 3.9 0.326 0.0002 0.0002 20.0 0.0002 0.326 0.337 3.2 0.349 0.0001 0.0001 -28.6 0.0001 0.349 0.348 -0.2 0.371 0.0000 0.0000 -100.0 0.0000 0.371 0.363 -2.3 Maximum positive excursion = 0.008 cfs (6.7%) occurring at 0.120 cfs on the Base Data (psetalbotpredev_020816.tsf) and at 0.128 cfs on the New Data (pserdout_020816.tsf). Maximum negative excursion = 0.019 cfs (-19.0%) occurring at 0.099 cfs on the Base Data (psetalbotpredev_020816.tsf) and at 0.080 cfs on the New Data (pserdout_020816.tsf). KCRTS Pond Design Results Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.00 H:1V Pond Bottom Length: 241.81 ft Pond Bottom Width: 27.00 ft Pond Bottom Area: 6529. sq. ft Top Area at 1 ft. FB: 16155. sq. ft 0.371 acres Effective Storage Depth: 7.00 ft Stage 0 Elevation: 425.50 ft Storage Volume: 73876. cu. ft 1.696 ac-ft Riser Head: 7.00 ft Riser Diameter: 12.00 inches Number of orifices: 3 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 1.15 0.095 2 4.85 2.13 0.180 6.0 3 6.10 2.00 0.103 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 425.50 0. 0.000 0.000 0.00 6529. 0.01 425.51 65. 0.001 0.004 0.00 6540. 0.02 425.52 131. 0.003 0.006 0.00 6551. 0.04 425.54 262. 0.006 0.007 0.00 6572. 0.05 425.55 328. 0.008 0.008 0.00 6583. 0.06 425.56 394. 0.009 0.009 0.00 6594. 0.07 425.57 460. 0.011 0.010 0.00 6604. 0.08 425.58 526. 0.012 0.010 0.00 6615. 0.10 425.60 658. 0.015 0.011 0.00 6637. 0.23 425.73 1530. 0.035 0.017 0.00 6777. 0.37 425.87 2490. 0.057 0.022 0.00 6929. 0.51 426.01 3470. 0.080 0.026 0.00 7082. 0.64 426.14 4400. 0.101 0.029 0.00 7224. 0.78 426.28 5422. 0.124 0.032 0.00 7377. 0.92 426.42 6466. 0.148 0.034 0.00 7532. 1.06 426.56 7531. 0.173 0.037 0.00 7687. 1.19 426.69 8540. 0.196 0.039 0.00 7831. 1.33 426.83 9647. 0.221 0.041 0.00 7987. 1.47 426.97 10776. 0.247 0.043 0.00 8144. 1.61 427.11 11928. 0.274 0.045 0.00 8302. 1.74 427.24 13016. 0.299 0.047 0.00 8448. 1.88 427.38 14210. 0.326 0.049 0.00 8607. 2.02 427.52 15426. 0.354 0.051 0.00 8766. 2.15 427.65 16576. 0.381 0.053 0.00 8915. 2.29 427.79 17835. 0.409 0.054 0.00 9075. 2.43 427.93 19117. 0.439 0.056 0.00 9236. 2.57 428.07 20421. 0.469 0.057 0.00 9398. 2.70 428.20 21653. 0.497 0.059 0.00 9549. 2.84 428.34 23001. 0.528 0.060 0.00 9712. 2.98 428.48 24372. 0.560 0.062 0.00 9875. 3.12 428.62 25766. 0.592 0.063 0.00 10040. 3.25 428.75 27081. 0.622 0.065 0.00 10193. 3.39 428.89 28520. 0.655 0.066 0.00 10358. 3.53 429.03 29981. 0.688 0.067 0.00 10524. 3.66 429.16 31359. 0.720 0.069 0.00 10679. 3.80 429.30 32866. 0.755 0.070 0.00 10846. 3.94 429.44 34396. 0.790 0.071 0.00 11014. 4.08 429.58 35950. 0.825 0.072 0.00 11182. 4.21 429.71 37414. 0.859 0.074 0.00 11339. 4.35 429.85 39013. 0.896 0.075 0.00 11509. 4.49 429.99 40637. 0.933 0.076 0.00 11679. 4.63 430.13 42284. 0.971 0.077 0.00 11850. 4.76 430.26 43835. 1.006 0.078 0.00 12010. 4.85 430.35 44920. 1.031 0.079 0.00 12120. 4.87 430.37 45163. 1.037 0.080 0.00 12145. 4.89 430.39 45406. 1.042 0.084 0.00 12170. 4.92 430.42 45772. 1.051 0.090 0.00 12207. 4.94 430.44 46016. 1.056 0.098 0.00 12231. 4.96 430.46 46261. 1.062 0.108 0.00 12256. 4.98 430.48 46507. 1.068 0.120 0.00 12281. 5.00 430.50 46752. 1.073 0.128 0.00 12305. 5.03 430.53 47122. 1.082 0.132 0.00 12342. 5.05 430.55 47369. 1.087 0.135 0.00 12367. 5.19 430.69 49113. 1.127 0.153 0.00 12541. 5.32 430.82 50754. 1.165 0.167 0.00 12702. 5.46 430.96 52544. 1.206 0.180 0.00 12877. 5.60 431.10 54359. 1.248 0.191 0.00 13052. 5.74 431.24 56199. 1.290 0.201 0.00 13228. 5.87 431.37 57929. 1.330 0.211 0.00 13392. 6.01 431.51 59816. 1.373 0.220 0.00 13569. 6.10 431.60 61043. 1.401 0.226 0.00 13683. 6.12 431.62 61317. 1.408 0.228 0.00 13709. 6.14 431.64 61591. 1.414 0.231 0.00 13734. 6.16 431.66 61866. 1.420 0.237 0.00 13760. 6.18 431.68 62141. 1.427 0.244 0.00 13785. 6.20 431.70 62417. 1.433 0.252 0.00 13811. 6.23 431.73 62832. 1.442 0.262 0.00 13849. 6.25 431.75 63109. 1.449 0.272 0.00 13874. 6.27 431.77 63387. 1.455 0.280 0.00 13900. 6.40 431.90 65205. 1.497 0.303 0.00 14066. 6.54 432.04 67187. 1.542 0.323 0.00 14246. 6.68 432.18 69194. 1.588 0.341 0.00 14426. 6.82 432.32 71226. 1.635 0.357 0.00 14606. 6.95 432.45 73136. 1.679 0.372 0.00 14775. 7.00 432.50 73876. 1.696 0.377 0.00 14840. 7.10 432.60 75367. 1.730 0.696 0.00 14970. 7.20 432.70 76870. 1.765 1.270 0.00 15100. 7.30 432.80 78387. 1.800 2.010 0.00 15231. 7.40 432.90 79916. 1.835 2.810 0.00 15362. 7.50 433.00 81459. 1.870 3.100 0.00 15493. 7.60 433.10 83015. 1.906 3.360 0.00 15625. 7.70 433.20 84584. 1.942 3.610 0.00 15757. 7.80 433.30 86167. 1.978 3.830 0.00 15889. 7.90 433.40 87762. 2.015 4.050 0.00 16022. 8.00 433.50 89371. 2.052 4.250 0.00 16155. 8.10 433.60 90993. 2.089 4.440 0.00 16288. 8.20 433.70 92629. 2.126 4.630 0.00 16422. 8.30 433.80 94278. 2.164 4.800 0.00 16556. 8.40 433.90 95940. 2.202 4.970 0.00 16690. 8.50 434.00 97616. 2.241 5.140 0.00 16825. 8.60 434.10 99305. 2.280 5.300 0.00 16960. 8.70 434.20 101008. 2.319 5.450 0.00 17095. 8.80 434.30 102724. 2.358 5.600 0.00 17230. 8.90 434.40 104454. 2.398 5.750 0.00 17366. Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 2.25 0.47 1.05 7.16 432.66 76281. 1.751 2 1.11 ******* 0.36 6.80 432.30 71008. 1.630 3 1.12 ******* 0.26 6.23 431.73 62802. 1.442 4 1.18 ******* 0.17 5.37 430.87 51439. 1.181 5 1.34 ******* 0.28 6.27 431.77 63431. 1.456 6 0.70 ******* 0.09 4.92 430.42 45833. 1.052 7 0.91 ******* 0.08 4.57 430.07 41528. 0.953 8 0.99 ******* 0.07 3.37 428.87 28288. 0.649 ---------------------------------- Route Time Series through Facility Inflow Time Series File:psetalbotdev_020816.tsf Outflow Time Series File:PSErdout_020816 Inflow/Outflow Analysis Peak Inflow Discharge: 2.25 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 1.04 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.16 Ft Peak Reservoir Elev: 432.66 Ft Peak Reservoir Storage: 76281. Cu-Ft : 1.751 Ac-Ft KCRTS Pre-developed and Developed Stormwater Pond Flow Output Predeveloped Peak Flows and Flow Frequency Analysis from KCRTS Flow Frequency Analysis Time Series File: psetalbotpredev_020816.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks- - Rank Return Prob (CFS) (CFS) Period 0.372 2 2/9/2001 18:00 0.475 1 100 0.99 0.101 7 1/6/2002 3:00 0.372 2 25 0.96 0.276 4 2/28/2003 3:00 0.285 3 10 0.9 0.010 8 3/24/2004 20:00 0.276 4 5 0.8 0.164 6 1/5/2005 8:00 0.241 5 3 0.667 0.285 3 1/18/2006 21:00 0.164 6 2 0.5 0.241 5 11/24/2006 4:00 0.101 7 1.3 0.231 0.475 1 1/9/2008 9:00 0.010 8 1.1 0.091 Computed Peaks 0.441 50 0.98 Developed Peak Flows and Flow Frequency Analysis before Stormwater Detention Pond from KCRTS Flow Frequency Analysis Time Series File: psetalbotdev_020816.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks- - Rank Return Prob (CFS) (CFS) Period 1.11 6 2/9/2001 2:00 2.25 1 100 0.99 0.912 8 1/5/2002 16:00 1.44 2 25 0.96 1.34 3 2/27/03 7:00 1.34 3 10 0.9 0.992 7 8/26/2004 2:00 1.20 4 5 0.8 1.20 4 10/28/2004 16:00 1.18 5 3 0.667 1.18 5 1/18/2006 16:00 1.11 6 2 0.5 1.44 2 10/26/2006 0:00 0.992 7 1.3 0.231 2.25 1 1/9/2008 6:00 0.912 8 1.1 0.091 Computed Peaks 1.98 50 0.98 Proposed Peak Flows and Flow Frequency Analysis from Stormwater Detention Pond from KCRTS Flow Frequency Analysis Time Series File:pserdout_020816.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks- - Rank Return Prob (CFS) (CFS) (ft) Period 0.363 2 2/9/2001 21:00 1.04 7.16 1 100 0.99 0.077 7 1/7/2002 4:00 0.363 6.87 2 25 0.96 0.281 3 3/6/2003 22:00 0.281 6.27 3 10 0.9 0.066 8 8/26/2004 7:00 0.261 6.23 4 5 0.8 0.092 6 1/8/2005 5:00 0.172 5.37 5 3 0.667 0.172 5 1/19/2006 0:00 0.092 4.92 6 2 0.5 0.261 4 11/24/2006 8:00 0.077 4.57 7 1.3 0.231 1.04 1 1/9/2008 10:00 0.066 3.37 8 1.1 0.091 Computed Peaks 0.818 7.12 50 0.98 This page intentionally left blank. KCRTS Pre-developed and Developed Flow Durations and Curve Predeveloped Flow Durations from KCRTS Flow Duration Time Series File: psetalbotpredev_020816.tsf Cutoff Count Frequency CDF Exceedance Probability CFS % % % 0.082 60744 99.061 99.061 0.939 9.39E-03 0.092 112 0.183 99.243 0.757 7.57E-03 0.103 72 0.117 99.361 0.639 6.39E-03 0.113 41 0.067 99.428 0.572 5.72E-03 0.123 40 0.065 99.493 0.507 5.07E-03 0.134 35 0.057 99.550 0.450 4.50E-03 0.144 37 0.060 99.610 0.390 3.90E-03 0.154 27 0.044 99.654 0.346 3.46E-03 0.164 23 0.038 99.692 0.308 3.08E-03 0.175 22 0.036 99.728 0.272 2.72E-03 0.185 18 0.029 99.757 0.243 2.43E-03 0.195 17 0.028 99.785 0.215 2.15E-03 0.206 23 0.038 99.822 0.178 1.78E-03 0.216 19 0.031 99.853 0.147 1.47E-03 0.226 12 0.020 99.873 0.127 1.27E-03 0.236 15 0.024 99.897 0.103 1.03E-03 0.247 13 0.021 99.918 0.082 8.15E-04 0.257 9 0.015 99.933 0.067 6.69E-04 0.267 9 0.015 99.948 0.052 5.22E-04 0.278 9 0.015 99.962 0.038 3.75E-04 0.288 5 0.008 99.971 0.029 2.94E-04 0.298 2 0.003 99.974 0.026 2.61E-04 0.309 3 0.005 99.979 0.021 2.12E-04 0.319 2 0.003 99.982 0.018 1.79E-04 0.329 1 0.002 99.984 0.016 1.63E-04 0.340 1 0.002 99.985 0.015 1.47E-04 0.350 4 0.007 99.992 0.008 8.15E-05 0.360 3 0.005 99.997 0.003 3.26E-05 0.370 1 0.002 99.998 0.002 1.63E-05 0.381 1 0.002 100.000 0.000 0.00E+00 0.391 0 0.000 100.000 0.000 0.00E+00 0.401 0 0.000 100.000 0.000 0.00E+00 0.412 0 0.000 100.000 0.000 0.00E+00 0.422 0 0.000 100.000 0.000 0.00E+00 0.432 0 0.000 100.000 0.000 0.00E+00 0.443 0 0.000 100.000 0.000 0.00E+00 0.432 0 0.000 100.000 0.000 0.00E+00 0.443 0 0.000 100.000 0.000 0.00E+00 Developed Flow Durations from Stormwater Detention Pond from KCRTS Flow Duration Time Series File: psetalbotpredev_020816.tsf Cutoff Count Frequency CDF Exceedance Probability CFS % % % 0.005 30750 50.147 50.147 49.853 4.99E-01 0.015 6754 11.014 61.161 38.839 3.88E-01 0.026 5291 8.629 69.790 30.210 3.02E-01 0.036 5511 8.987 78.777 21.223 2.12E-01 0.046 4878 7.955 86.732 13.268 1.33E-01 0.056 3407 5.556 92.288 7.712 7.71E-02 0.066 2133 3.478 95.766 4.234 4.23E-02 0.077 1820 2.968 98.735 1.265 1.27E-02 0.087 390 0.636 99.371 0.629 6.29E-03 0.097 33 0.054 99.424 0.576 5.76E-03 0.107 11 0.018 99.442 0.558 5.58E-03 0.117 10 0.016 99.459 0.541 5.41E-03 0.128 10 0.016 99.475 0.525 5.25E-03 0.138 43 0.070 99.545 0.455 4.55E-03 0.148 43 0.070 99.615 0.385 3.85E-03 0.158 41 0.067 99.682 0.318 3.18E-03 0.168 31 0.051 99.733 0.267 2.67E-03 0.178 29 0.047 99.780 0.220 2.20E-03 0.189 20 0.033 99.812 0.188 1.88E-03 0.199 15 0.024 99.837 0.163 1.63E-03 0.209 21 0.034 99.871 0.129 1.29E-03 0.219 16 0.026 99.897 0.103 1.03E-03 0.229 15 0.024 99.922 0.078 7.83E-04 0.24 6 0.010 99.932 0.068 6.85E-04 0.25 4 0.007 99.938 0.062 6.20E-04 0.26 6 0.010 99.948 0.052 5.22E-04 0.27 4 0.007 99.954 0.046 4.57E-04 0.28 4 0.007 99.961 0.039 3.91E-04 0.291 6 0.010 99.971 0.029 2.94E-04 0.301 1 0.002 99.972 0.028 2.77E-04 0.311 2 0.003 99.976 0.024 2.45E-04 0.321 2 0.003 99.979 0.021 2.12E-04 0.331 3 0.005 99.984 0.016 1.63E-04 0.342 2 0.003 99.987 0.013 1.30E-04 0.352 3 0.005 99.992 0.008 8.15E-05 0.362 4 0.007 99.998 0.002 1.63E-05 This page intentionally left blank. 00.050.10.150.20.250.30.350.41.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00Discharge (CFS)Probability ExceedenceFlow Duration Analysis from KCRTSDevelopedConditionsPredevelopedConditions This page intentionally left blank. Rational Method Documentation Rational Method Rational Method Pipe Capacity Analysis Subbasin Name Area (ft2) Area (ac)Impervious Area (%)Runoff from Impervious Area (cfs)Runoff from Pervious Area (cfs)Total Runoff (cfs)Cumulative Flow in System (cfs)Downstream Pipe NamePipe Full Flow Capacity from XPSWMM (cfs)Compliant with Capacity Requirement?Runoff from Impervious Area (cfs)Runoff from Pervious Area (cfs)Total Runoff (cfs)Cumulative Flow in System (cfs)CB101783.80.0410.650.0200.0100.0300.030Link40.940Yes0.0230.0120.0340.034CB112272.80.0520.650.0250.0130.0380.068Link50.940Yes0.0290.0150.0440.078CB122504.30.0570.650.0280.0140.0420.110Link60.940Yes0.0320.0160.0480.126CB132324.60.0530.650.0260.0130.0390.149Link70.940Yes0.0300.0150.0450.170CB142243.20.0510.650.0250.0130.0380.186Link80.940Yes0.0290.0150.0430.213CB152279.50.0520.650.0250.0130.0380.284Link90.940Yes0.0290.0150.0440.326CB162101.10.0480.650.0230.0120.0350.319Link100.940Yes0.0270.0140.0400.366CB172260.60.0520.650.0250.0130.0380.357Link110.950Yes0.0290.0150.0430.409CB182388.40.0550.650.0260.0130.0400.397Link120.940Yes0.0300.0150.0460.455CB192369.60.0540.650.0260.0130.0400.437Link130.910Yes0.0300.0150.0450.501CB202541.30.0580.650.0280.0140.0420.479Link142.730Yes0.0320.0160.0490.549CB211809.50.0420.650.0200.0100.0300.509Link152.710Yes0.0230.0120.0350.584CB224239.40.0970.650.0470.0240.0710.071Link190.940Yes0.0540.0270.0810.081CB2372070.1650.650.0800.0410.1200.191Link200.940Yes0.0920.0470.1380.220CB245143.60.1180.650.0570.0290.0860.277Link211.100Yes0.0650.0330.0990.318CB253582.30.0820.650.0400.0200.0600.337Link220.950Yes0.0460.0230.0690.387CB265034.80.1160.650.0560.0280.0840.084Link160.940Yes0.0640.0330.0970.097CB277103.40.1630.650.0790.0400.1190.203Link170.940Yes0.0900.0460.1360.233CB284914.90.1130.650.0540.0280.0820.285Link182.730Yes0.0620.0320.0940.327CB292539.30.0580.650.0280.0140.0422.571Link542.730Yes0.0320.0160.0492.950CB304221.20.0970.650.0470.0240.0710.071Link230.940Yes0.0540.0270.0810.081CB317300.10.1680.650.0810.0410.1220.193Link240.940Yes0.0930.0470.1400.221CB325210.80.1200.650.0580.0290.0870.280Link250.940Yes0.0660.0340.1000.321CB333677.30.0840.650.0410.0210.0610.341Link260.940Yes0.0470.0240.0710.391CB345122.10.1180.650.0570.0290.0860.086Link270.940Yes0.0650.0330.0980.098CB357241.60.1660.650.0800.0410.1210.207Link280.940Yes0.0920.0470.1390.237CB365030.20.1150.650.0560.0280.0840.291Link292.730Yes0.0640.0330.0960.334CB372586.90.0590.650.0290.0150.0431.735Link302.730Yes0.0330.0170.0501.990CB385872.50.1350.650.0650.0330.0980.098Link310.940Yes0.0750.0380.1130.113CB394688.80.1080.650.0520.0260.0780.232Link320.940Yes0.0600.0300.0900.266CB403307.20.0760.650.0370.0190.0550.055Link440.940Yes0.0420.0210.0630.063CB415186.10.1190.650.0570.0290.0870.319Link330.940Yes0.0660.0340.0990.365CB423599.20.0830.650.0400.0200.0600.060Link430.940Yes0.0460.0230.0690.069CB434345.90.1000.650.0480.0240.0730.864Link342.110Yes0.0550.0280.0830.992CB4438950.0890.650.0430.0220.0650.971Link352.750Yes0.0500.0250.0751.114CB4537950.0870.650.0420.0210.0631.210Link372.730Yes0.0480.0250.0731.388CB4628290.0650.650.0310.0160.0470.075Link410.940Yes0.0360.0180.0540.086CB471648.90.03810.0280.0000.0280.028Link450.950Yes0.0320.0000.0320.032CB484692.40.1080.650.0520.0260.0781.336Link382.730Yes0.0600.0300.0901.533CB492852.10.0650.650.0320.0160.0480.048Link400.940Yes0.0360.0180.0550.055CB503854.10.0880.650.0430.0220.0641.401Link392.730Yes0.0490.0250.0741.607CB512488.90.0570.650.0280.0140.0420.042Link530.470Yes0.0320.0160.0480.048CB521505.10.0350.650.0170.0080.0250.025Link480.470Yes0.0190.0100.0290.029CB531460.60.0340.650.0160.0080.0240.050Link490.470Yes0.0190.0090.0280.05725-yr Capacity Analysis25-yr Flows (cfs)100-yr Flows (cfs) CB542481.80.0570.650.0280.0140.0410.041Link520.470Yes0.0320.0160.0480.048CB551492.60.0340.650.0170.0080.0250.050Link510.470Yes0.0190.0100.0290.057CB561489.50.0340.650.0170.0080.0250.025Link500.520Yes0.0190.0100.0290.029CB573437.50.0790.650.0380.0190.0571.071Link362.730Yes0.0440.0220.0661.229CB582562.50.0590.650.0280.0140.0430.043Link420.940Yes0.0330.0170.0490.049GI-12475.20.0570.650.0270.0140.0410.133Link471.030Yes0.0310.0160.0470.152GI-22440.20.0560.650.0270.0140.0410.132Link461.030Yes0.0310.0160.0470.151 Rational Method Coefficient0.85for gravel pavement0.9for pavementRainfall Intensity (ft/s)0.00002for 25-yr0.00002for 100-yr This page intentionally left blank. XPSWMM Model Documentation XPSWMM XPSWMM Model Schematic This page intentionally left blank. XPSWMM Catch Basin (Node) & Pipe (Link) Input Data Link Input Data Summary Link Name Upstream Node Name Downstream Node Name Upstream Invert Elevation (ft) Downstream Invert Elevation (ft) Diameter (ft) Length (ft) Conduit Slope (%) Roughness Link4 CB10 CB11 436.51 436.26 0.67 50 0.5 0.012 Link5 CB11 CB12 436.26 435.96 0.67 60 0.5 0.012 Link6 CB12 CB13 435.96 435.66 0.67 60 0.5 0.012 Link7 CB13 CB14 435.66 435.41 0.67 50 0.5 0.012 Link8 CB14 CB15 435.24 434.92 0.67 64 0.5 0.012 Link9 CB15 CB16 434.5 434.27 0.67 46 0.5 0.012 Link10 CB16 CB17 434.27 434.02 0.67 50 0.5 0.012 Link11 CB17 CB18 434.02 433.73 0.67 57 0.5 0.012 Link12 CB18 CB19 433.73 433.48 0.67 50 0.5 0.012 Link13 CB19 CB20 433.48 433.21 0.67 58 0.5 0.012 Link14 CB20 CB21 432.88 432.58 1 60 0.5 0.012 Link15 CB21 CB29 432.58 432.26 1 65 0.5 0.012 Link54 CB29 Pond 430.69 430.5 1 38 0.5 0.012 Link18 CB28 CB29 435.13 434.83 1 60 0.5 0.012 Link17 CB27 CB28 435.77 435.23 0.67 108 0.5 0.012 Link16 CB26 CB27 436.42 435.87 0.67 110 0.5 0.012 Link22 CB25 CB15 434.94 434.6 0.67 67 0.5 0.012 Link21 CB24 CB25 435.34 434.97 0.67 54 0.5 0.012 Link20 CB23 CB24 435.96 435.41 0.67 110 0.5 0.012 Link19 CB22 CB23 436.51 435.96 0.67 110 0.5 0.012 Link30 CB37 CB29 430.98 430.69 1 58 0.5 0.012 Link28 CB35 CB36 435.88 435.34 0.67 108 0.5 0.012 Link29 CB36 CB37 435.01 434.71 1 60 0.5 0.012 Link27 CB34 CB35 436.42 435.88 0.67 108 0.5 0.012 Link39 CB50 CB37 431.36 430.98 1 76 0.5 0.012 Link38 CB48 CB50 431.66 431.36 1 60 0.5 0.012 Link37 CB45 CB48 432.53 431.99 1 108 0.5 0.012 Link36 CB57 CB45 434.11 433.81 1 60 0.5 0.012 Link35 CB44 CB57 434.44 434.11 1 65 0.5 0.012 Link34 CB43 CB44 434.54 434.45 1 17 0.5 0.012 Link33 CB41 CB43 435.49 435.12 0.67 74 0.5 0.012 Link32 CB39 CB41 436.21 435.66 0.67 110 0.5 0.012 Link31 CB38 CB39 436.51 436.21 0.67 60 0.5 0.012 Link26 CB33 CB43 434.92 434.54 0.67 76 0.5 0.012 Link25 CB32 CB33 435.24 434.92 0.67 64 0.5 0.012 Link24 CB31 CB32 435.96 435.41 0.67 110 0.5 0.012 Link23 CB30 CB31 436.51 435.96 0.67 110 0.5 0.012 Link44 CB40 CB39 436.45 436.25 0.67 40 0.5 0.012 Link43 CB42 CB41 436.25 436.05 0.67 40 0.5 0.012 Link42 CB58 CB57 436 435.8 0.67 40 0.5 0.012 Link40 CB49 CB48 436 435.8 0.67 40 0.5 0.012 Link41 CB46 CB45 432.75 432.6 0.67 30 0.5 0.012 Link45 CB47 CB46 432.98 432.75 0.67 45 0.5 0.012 Link46 GI-2 CB43 435.21 434.79 0.67 83 0.5 0.011 Link47 GI-1 CB44 435.21 434.79 0.67 83 0.5 0.011 Link51 CB55 GI-1 435.93 435.71 0.5 43 0.5 0.011 Link50 CB56 CB55 436.45 435.93 0.5 83 0.5 0.011 Link52 CB54 GI-1 436.25 435.84 0.5 83 0.5 0.011 Link49 CB53 GI-2 435.93 435.71 0.5 43 0.5 0.011 Link48 CB52 CB53 436.45 436.03 0.5 83 0.5 0.011 Link53 CB51 GI-2 436.25 435.84 0.5 83 0.5 0.011 (Link 55) riserweir Pond OF NA NA NA NA NA NA (Link 55) bottom orifice Pond OF NA NA 0.10 NA NA NA (Link 55) side#1 Pond OF NA NA 0.18 NA NA NA (Link 55) side#2 Pond OF NA NA 0.17 NA NA NA Node Hydraulic Input Data Node Name Ground Elevation Spill Crest (ft) Invert Elevation (ft) CB10 437.92 436.51 CB11 437.92 436.26 CB12 437.92 435.96 CB13 437.92 435.66 CB14 437.92 435.24 CB15 437.92 434.5 CB16 437.92 434.27 CB17 437.92 434.02 CB18 437.92 433.73 CB19 437.92 433.48 CB20 437.92 432.88 CB21 437.92 432.58 CB29 437.92 430.69 CB28 437.75 435.13 CB27 437.75 435.77 CB26 437.75 436.42 CB25 437.75 434.94 CB24 437.75 435.24 CB23 437.75 435.96 CB22 437.75 436.51 CB37 437.92 430.98 CB35 437.75 435.88 CB36 437.75 435.01 CB34 437.75 436.42 CB50 437.92 431.36 CB48 437.75 431.66 CB45 437.75 432.53 CB57 437.75 434.11 CB44 437.75 434.44 CB43 437.75 434.54 CB41 437.75 435.49 CB39 437.75 436.21 CB38 437.75 436.51 CB33 437.75 434.92 CB32 437.75 435.24 CB31 437.75 435.96 CB30 437.75 436.51 CB40 437.54 436.45 CB42 437.5 436.25 CB58 437.5 436 CB49 437.75 436 CB46 437.75 432.75 CB47 437.75 432.98 GI-2 439.65 435.21 GI-1 439.65 435.21 CB55 438.25 435.93 CB56 438.25 436.45 CB54 438.25 436.25 CB53 438.25 435.93 CB52 438.25 436.45 CB51 438.25 436.25 Pond 437.5 425.5 OF 437.5 425 Node Runoff Input Data Node Name Area (ac) Slope (ft/ft) Impervious Percentage (%) Width (ft) CB10 0.041 0.003 65 43 CB11 0.052 0.003 65 55 CB12 0.057 0.003 65 60 CB13 0.053 0.003 65 55 CB14 0.051 0.003 65 57 CB15 0.052 0.003 65 54 CB16 0.048 0.003 65 49 CB17 0.052 0.003 65 52 CB18 0.055 0.003 65 55 CB19 0.054 0.003 65 54 CB20 0.058 0.003 65 58 CB21 0.042 0.003 65 44 CB29 0.058 0.003 65 63 CB28 0.113 0.003 65 79 CB27 0.163 0.003 65 113 CB26 0.116 0.003 65 80 CB25 0.082 0.003 65 63 CB24 0.118 0.003 65 82 CB23 0.165 0.003 65 114 CB22 0.097 0.003 65 67 CB37 0.059 0.003 67 64 CB35 0.166 0.003 65 114 CB36 0.115 0.003 65 79 CB34 0.118 0.003 65 80 CB50 0.088 0.003 65 95 CB48 0.108 0.003 65 79 CB45 0.087 0.003 65 69 CB57 0.079 0.003 65 62.5 CB44 0.089 0.003 65 95 CB43 0.1 0.003 65 95 CB41 0.119 0.003 65 92 CB39 0.108 0.003 65 84 CB38 0.135 0.003 65 46 CB33 0.084 0.003 65 64 CB32 0.12 0.003 65 82 CB31 0.168 0.003 65 114 CB30 0.097 0.003 65 67 CB40 0.076 0.003 65 84 CB42 0.083 0.003 65 93 CB58 0.059 0.003 65 62.5 CB49 0.065 0.003 65 80 CB46 0.065 0.003 65 69 CB47 0.038 0.003 65 41 GI-2 0.056 0.003 65 50 GI-1 0.057 0.003 65 50 CB55 0.034 0.003 65 50 CB56 0.034 0.003 65 50 CB54 0.057 0.003 65 50 CB53 0.035 0.003 65 49 CB52 0.035 0.003 65 40 CB51 0.057 0.003 65 50 Pond NA NA NA NA OF NA NA NA NA XPSWMM Catch Basin (Node) & Pipe (Link) Output Summary Node Output Data Summary for 25-year Event Node Name Max Water Elevation (ft) Max Water Depth (ft) Freeboard (ft) Duration of Surcharge (min) Duration of Flooding (min) CB10 436.590 0.080 1.33 0.0 0.0 CB11 436.379 0.119 1.54 0.0 0.0 CB12 436.110 0.150 1.81 0.0 0.0 CB13 435.837 0.177 2.08 0.0 0.0 CB14 435.438 0.198 2.48 0.0 0.0 CB15 434.864 0.364 3.06 0.0 0.0 CB16 434.648 0.378 3.27 0.0 0.0 CB17 434.411 0.391 3.51 0.0 0.0 CB18 434.141 0.411 3.78 0.0 0.0 CB19 433.911 0.431 4.01 0.0 0.0 CB20 433.230 0.350 4.69 0.0 0.0 CB21 432.938 0.358 4.98 0.0 0.0 CB29 431.476 0.786 6.44 0.0 0.0 CB28 435.343 0.213 2.41 0.0 0.0 CB27 435.978 0.208 1.77 0.0 0.0 CB26 436.554 0.134 1.20 0.0 0.0 CB25 435.210 0.270 2.54 0.0 0.0 CB24 435.563 0.323 2.19 0.0 0.0 CB23 436.162 0.202 1.59 0.0 0.0 CB22 436.631 0.121 1.12 0.0 0.0 CB37 431.639 0.659 6.28 0.0 0.0 CB35 436.090 0.210 1.66 0.0 0.0 CB36 435.225 0.215 2.53 0.0 0.0 CB34 436.554 0.134 1.20 0.0 0.0 CB50 431.908 0.548 6.01 0.0 0.0 CB48 432.178 0.518 5.57 0.0 0.0 CB45 433.015 0.485 4.73 0.0 0.0 CB57 434.566 0.456 3.18 0.0 0.0 CB44 434.875 0.435 2.87 0.0 0.0 CB43 434.982 0.442 2.77 0.0 0.0 CB41 435.780 0.290 1.97 0.0 0.0 CB39 436.433 0.223 1.32 0.0 0.0 CB38 436.652 0.142 1.10 0.0 0.0 CB33 435.203 0.283 2.55 0.0 0.0 CB32 435.485 0.245 2.26 0.0 0.0 CB31 436.163 0.203 1.59 0.0 0.0 CB30 436.631 0.121 1.12 0.0 0.0 CB40 436.558 0.108 0.98 0.0 0.0 CB42 436.364 0.114 1.14 0.0 0.0 CB58 436.097 0.097 1.40 0.0 0.0 CB49 436.102 0.102 1.65 0.0 0.0 CB46 433.017 0.267 4.73 0.0 0.0 CB47 433.057 0.077 4.69 0.0 0.0 GI-2 435.369 0.159 4.28 0.0 0.0 GI-1 435.368 0.158 4.28 0.0 0.0 CB55 436.037 0.107 2.21 0.0 0.0 CB56 436.522 0.072 1.73 0.0 0.0 CB54 436.349 0.099 1.90 0.0 0.0 CB53 436.038 0.108 2.21 0.0 0.0 CB52 436.528 0.078 1.72 0.0 0.0 CB51 436.349 0.099 1.90 0.0 0.0 OF 425.536 1.151 11.96 0.0 0.0 Node Output Data Summary for 100-year Event Node Name Max Water Elevation (ft) Max Water Depth (ft) Freeboard (ft) Duration of Surcharge (min) Duration of Flooding (min) CB10 436.596 0.086 1.32 0.0 0.0 CB11 436.389 0.129 1.53 0.0 0.0 CB12 436.123 0.163 1.80 0.0 0.0 CB13 435.852 0.192 2.07 0.0 0.0 CB14 435.455 0.215 2.46 0.0 0.0 CB15 434.904 0.404 3.02 0.0 0.0 CB16 434.691 0.421 3.23 0.0 0.0 CB17 434.457 0.437 3.46 0.0 0.0 CB18 434.190 0.460 3.73 0.0 0.0 CB19 433.960 0.480 3.96 0.0 0.0 CB20 433.262 0.382 4.66 0.0 0.0 CB21 432.971 0.391 4.95 0.0 0.0 CB29 431.570 0.880 6.35 0.0 0.0 CB28 435.361 0.231 2.39 0.0 0.0 CB27 435.996 0.226 1.75 0.0 0.0 CB26 436.565 0.145 1.18 0.0 0.0 CB25 435.234 0.294 2.52 0.0 0.0 CB24 435.583 0.343 2.17 0.0 0.0 CB23 436.179 0.219 1.57 0.0 0.0 CB22 436.641 0.131 1.11 0.0 0.0 CB37 431.737 0.757 6.18 0.0 0.0 CB35 436.109 0.229 1.64 0.0 0.0 CB36 435.243 0.233 2.51 0.0 0.0 CB34 436.565 0.145 1.19 0.0 0.0 CB50 431.982 0.622 5.94 0.0 0.0 CB48 432.237 0.577 5.51 0.0 0.0 CB45 433.065 0.535 4.69 0.0 0.0 CB57 434.610 0.500 3.14 0.0 0.0 CB44 434.918 0.478 2.83 0.0 0.0 CB43 435.023 0.483 2.73 0.0 0.0 CB41 435.808 0.318 1.94 0.0 0.0 CB39 436.453 0.243 1.30 0.0 0.0 CB38 436.664 0.154 1.09 0.0 0.0 CB33 435.234 0.314 2.52 0.0 0.0 CB32 435.509 0.269 2.24 0.0 0.0 CB31 436.180 0.220 1.57 0.0 0.0 CB30 436.641 0.131 1.11 0.0 0.0 CB40 436.567 0.117 0.97 0.0 0.0 CB42 436.373 0.123 1.13 0.0 0.0 CB58 436.105 0.105 1.40 0.0 0.0 CB49 436.110 0.110 1.64 0.0 0.0 CB46 433.066 0.316 4.68 0.0 0.0 CB47 433.081 0.101 4.67 0.0 0.0 GI-2 435.382 0.172 4.27 0.0 0.0 GI-1 435.382 0.172 4.27 0.0 0.0 CB55 436.045 0.115 2.20 0.0 0.0 CB56 436.528 0.078 1.72 0.0 0.0 CB54 436.357 0.107 1.89 0.0 0.0 CB53 436.047 0.117 2.20 0.0 0.0 CB52 436.534 0.084 1.72 0.0 0.0 CB51 436.357 0.107 1.89 0.0 0.0 Pond 429.500 5.105 8.00 0.0 0.0 OF 425.536 1.151 11.96 101.135 0.0 Link Output Data Summary for 25-year Event Link Name Upstream Node Name Downstream Node Name Design Full Flow (cfs) Max Depth (ft) Max d/D (depth/diameter) Max Flow (cfs) Max Tailwater (ft) Max Headwater (ft) Link4 CB10 CB11 0.94 0.119 0.177 0.028 436.379 436.590 Link5 CB11 CB12 0.94 0.150 0.225 0.064 436.110 436.379 Link6 CB12 CB13 0.94 0.177 0.264 0.104 435.837 436.110 Link7 CB13 CB14 0.94 0.177 0.264 0.140 435.581 435.837 Link8 CB14 CB15 0.94 0.198 0.296 0.176 435.112 435.438 Link9 CB15 CB16 0.94 0.378 0.564 0.531 434.648 434.864 Link10 CB16 CB17 0.94 0.391 0.584 0.564 434.411 434.648 Link11 CB17 CB18 0.95 0.411 0.613 0.600 434.141 434.411 Link12 CB18 CB19 0.94 0.431 0.644 0.637 433.911 434.141 Link13 CB19 CB20 0.91 0.431 0.644 0.675 433.596 433.911 Link14 CB20 CB21 2.73 0.358 0.358 0.715 432.938 433.230 Link15 CB21 CB29 2.71 0.358 0.358 0.743 432.618 432.938 Link54 CB29 Pond 2.73 0.786 0.786 2.842 431.223 431.476 Link18 CB28 CB29 2.73 0.213 0.213 0.271 435.042 435.343 Link17 CB27 CB28 0.94 0.208 0.311 0.193 435.431 435.978 Link16 CB26 CB27 0.94 0.134 0.201 0.080 435.998 436.554 Link22 CB25 CB15 0.95 0.270 0.403 0.319 434.864 435.210 Link21 CB24 CB25 1.10 0.240 0.358 0.263 435.210 435.563 Link20 CB23 CB24 0.94 0.202 0.301 0.181 435.605 436.162 Link19 CB22 CB23 0.94 0.202 0.301 0.067 436.162 436.631 Link30 CB37 CB29 2.73 0.786 0.786 1.788 431.476 431.639 Link28 CB35 CB36 0.94 0.210 0.314 0.196 435.543 436.090 Link29 CB36 CB37 2.73 0.215 0.215 0.276 434.924 435.225 Link27 CB34 CB35 0.94 0.210 0.314 0.082 436.090 436.554 Link39 CB50 CB37 2.73 0.659 0.659 1.472 431.639 431.908 Link38 CB48 CB50 2.73 0.548 0.548 1.411 431.908 432.178 Link37 CB45 CB48 2.73 0.485 0.485 1.292 432.470 433.015 Link36 CB57 CB45 2.73 0.456 0.456 1.161 434.264 434.566 Link35 CB44 CB57 2.75 0.456 0.456 1.066 434.566 434.875 Link34 CB43 CB44 2.11 0.442 0.442 0.879 434.875 434.982 Link33 CB41 CB43 0.94 0.291 0.434 0.359 435.398 435.780 Link32 CB39 CB41 0.94 0.223 0.333 0.220 435.875 436.433 Link31 CB38 CB39 0.94 0.223 0.333 0.093 436.433 436.652 Link26 CB33 CB43 0.94 0.442 0.659 0.324 434.981 435.203 Link25 CB32 CB33 0.94 0.283 0.422 0.266 435.203 435.485 Link24 CB31 CB32 0.94 0.203 0.303 0.183 435.606 436.163 Link23 CB30 CB31 0.94 0.203 0.303 0.067 436.163 436.631 Link44 CB40 CB39 0.94 0.183 0.273 0.053 436.433 436.558 Link43 CB42 CB41 0.94 0.114 0.170 0.057 436.158 436.364 Link42 CB58 CB57 0.94 0.097 0.145 0.041 435.890 436.097 Link40 CB49 CB48 0.94 0.102 0.152 0.045 435.895 436.102 Link41 CB46 CB45 0.94 0.415 0.620 0.071 433.015 433.017 Link45 CB47 CB46 0.95 0.267 0.398 0.026 433.017 433.057 Link46 GI-2 CB43 1.03 0.192 0.286 0.127 434.981 435.369 Link47 GI-1 CB44 1.03 0.158 0.236 0.126 434.948 435.368 Link51 CB55 GI-1 0.47 0.107 0.213 0.047 435.816 436.037 Link50 CB56 CB55 0.52 0.107 0.213 0.024 436.037 436.522 Link52 CB54 GI-1 0.47 0.099 0.198 0.039 435.937 436.349 Link49 CB53 GI-2 0.47 0.108 0.216 0.048 435.817 436.038 Link48 CB52 CB53 0.47 0.078 0.156 0.024 436.105 436.528 Link53 CB51 GI-2 0.47 0.099 0.198 0.039 435.937 436.349 Link56 Pond OF 0.00 -9.00E+99 0.000 0.000 0.000 0.000 Link56 Pond OF 8.95 5.103 4.434 16.008 425.536 429.135 Link56 Pond OF 41.69 0.253 0.119 0.068 429.322 429.478 Link56 Pond OF 35.63 -9.00E+99 0.000 0.000 0.000 0.000 Link Output Data Summary for 100-year Event Link Name Upstream Node Name Downstream Node Name Design Full Flow (cfs) Max Depth (ft) Max d/D (depth/ diameter) Max Flow (cfs) Max Tailwater (ft) Max Headwater (ft) Link4 CB10 CB11 0.94 0.129 0.192 0.033 436.389 436.596 Link5 CB11 CB12 0.94 0.163 0.243 0.076 436.123 436.389 Link6 CB12 CB13 0.94 0.192 0.286 0.122 435.852 436.123 Link7 CB13 CB14 0.94 0.192 0.286 0.165 435.596 435.852 Link8 CB14 CB15 0.94 0.215 0.321 0.206 435.128 435.455 Link9 CB15 CB16 0.94 0.421 0.628 0.623 434.691 434.904 Link10 CB16 CB17 0.94 0.437 0.652 0.662 434.457 434.691 Link11 CB17 CB18 0.95 0.460 0.687 0.704 434.190 434.457 Link12 CB18 CB19 0.94 0.480 0.717 0.749 433.960 434.190 Link13 CB19 CB20 0.91 0.480 0.717 0.792 433.630 433.960 Link14 CB20 CB21 2.73 0.391 0.391 0.840 432.971 433.262 Link15 CB21 CB29 2.71 0.391 0.391 0.873 432.650 432.971 Link54 CB29 Pond 2.73 0.880 0.880 3.339 431.281 431.570 Link18 CB28 CB29 2.73 0.231 0.231 0.318 435.060 435.361 Link17 CB27 CB28 0.94 0.226 0.338 0.226 435.449 435.996 Link16 CB26 CB27 0.94 0.145 0.217 0.094 436.009 436.565 Link22 CB25 CB15 0.95 0.304 0.454 0.375 434.904 435.234 Link21 CB24 CB25 1.10 0.264 0.394 0.309 435.234 435.583 Link20 CB23 CB24 0.94 0.219 0.327 0.213 435.622 436.179 Link19 CB22 CB23 0.94 0.219 0.327 0.079 436.179 436.641 Link30 CB37 CB29 2.73 0.880 0.880 2.101 431.570 431.737 Link28 CB35 CB36 0.94 0.229 0.341 0.231 435.561 436.109 Link29 CB36 CB37 2.73 0.233 0.233 0.324 434.942 435.243 Link27 CB34 CB35 0.94 0.229 0.341 0.096 436.109 436.565 Link39 CB50 CB37 2.73 0.757 0.757 1.729 431.737 431.982 Link38 CB48 CB50 2.73 0.622 0.622 1.658 431.982 432.237 Link37 CB45 CB48 2.73 0.535 0.535 1.518 432.512 433.065 Link36 CB57 CB45 2.73 0.500 0.500 1.364 434.304 434.610 Link35 CB44 CB57 2.75 0.500 0.500 1.252 434.610 434.918 Link34 CB43 CB44 2.11 0.483 0.483 1.033 434.918 435.023 Link33 CB41 CB43 0.94 0.318 0.475 0.422 435.422 435.808 Link32 CB39 CB41 0.94 0.243 0.362 0.258 435.894 436.453 Link31 CB38 CB39 0.94 0.243 0.362 0.109 436.453 436.664 Link26 CB33 CB43 0.94 0.483 0.722 0.381 435.023 435.234 Link25 CB32 CB33 0.94 0.314 0.469 0.313 435.234 435.509 Link24 CB31 CB32 0.94 0.220 0.329 0.215 435.623 436.180 Link23 CB30 CB31 0.94 0.220 0.329 0.079 436.180 436.641 Link44 CB40 CB39 0.94 0.203 0.303 0.062 436.453 436.567 Link43 CB42 CB41 0.94 0.123 0.184 0.067 436.167 436.373 Link42 CB58 CB57 0.94 0.105 0.156 0.048 435.898 436.105 Link40 CB49 CB48 0.94 0.110 0.164 0.053 435.903 436.110 Link41 CB46 CB45 0.94 0.465 0.694 0.084 433.060 433.062 Link45 CB47 CB46 0.95 0.316 0.472 0.031 433.066 433.081 Link46 GI-2 CB43 1.03 0.233 0.348 0.149 435.023 435.382 Link47 GI-1 CB44 1.03 0.172 0.256 0.148 434.961 435.382 Link51 CB55 GI-1 0.47 0.115 0.231 0.055 435.825 436.045 Link50 CB56 CB55 0.52 0.115 0.231 0.028 436.045 436.528 Link52 CB54 GI-1 0.47 0.107 0.214 0.046 435.945 436.357 Link49 CB53 GI-2 0.47 0.117 0.234 0.057 435.827 436.047 Link48 CB52 CB53 0.47 0.084 0.168 0.028 436.112 436.534 Link53 CB51 GI-2 0.47 0.107 0.214 0.046 435.945 436.357 Link55 Pond OF 0.00 -9.00E+99 0 0 0 0 Link55 Pond OF 8.95 5.103 4.434 16.008 425.536 429.135 Link55 Pond OF 41.69 0.253 0.119 0.068 429.322 429.478 Link55 Pond OF 35.63 -9.00E+99 0 0 0 0 This page intentionally left blank. Appendix F CSWPPP This page intentionally left blank. Appendix G Facilities Summary and Declaration of Covenant KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual 1/9/2009 KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL REFERENCE 8-D FLOW CONTROL AND WATER QUALITY FACILITY SUMMARY SHEET AND SKETCH KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual 1/9/2009 1 STORMWATER FACILITY SUMMARY SHEET DDES Permit Number__________________ (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Overview: Project Name _______________________________________________________Date___________________ Downstream Drainage Basins Major Basin Name _____________________________ Immediate Basin Name __________________________ Flow Control: Flow Control Facility Name/Number ________________________________ Facility Location________________________________________________________________________ ___ If none, Flow control provided in regional/shared facility (give location)___________________________________ No flow control required_____________ Exemption number _______________________________ General Facility Information: Type/Number of detention facilities: Type/Number of infiltration facilities: ______ ponds ______ ponds ______ vaults ______ tanks ______ tanks ______ trenches Control Structure Location _____________________________________________________________________ Type of Control Structure ______________________________ Number of Orifices/Restrictions _____________ Size of Orifice/Restriction: No. 1 ________________ No. 2 ________________ No. 3 ________________ No. 4 ________________ Flow Control Performance Standard _________________________________ KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual 1/9/2009 2 Live Storage Volume __________________ Depth _______________ Volume Factor of Safety ________________ Number of Acres Served ____________________ Number of Lots ____________________ Dam Safety Regulations (Washington State Department of Ecology) Reservoir Volume above natural grade ________________ Depth of Reservoir above natural grade _______________ Facility Summary Sheet Sketch All detention, infiltration and water quality facilities must include a detailed sketch. (11"x17" reduced size plan sheets may be used) Propose dDischarge Point No access topond from inside the substation ProposedStormwaterDetention Pond Control Structure Location PondAccessRoad PATH: G:\PROJEC TS\WAS HINGTON\PUGET_SOUND_EN ERGY_00 702 2\TAL BOT_STORMWATER_SUPPORT_2699 66\MAP_DOCS \DRAF T\T IR FIGURES\APPENDIX G FACILT Y SKE TCH.MX D - USER: TAHOF FMA - DATE: 11/16 /20 16 TALBOT STORMWATER SUPPORT APPENDIX G FLOW CONTROL FA CILITY SKETCH STORMWATER TIR 0 150Feet O DATA SOURCE: City of Renton,King County (2016) LEGEND Project Are a Con to urs - 10 ft In te rval Propo sed C on tro lStructure Propo sedFlow Pa th Propo sedDrainageInfrastructur e Propo sedDetention Pond Propo sed Acce ssRoad 2009 Surface Water Design Manual Amendment City of Renton CITY OF RENTON AMENDMENTS TO THE KING COUNTY SURFACE WATER DESIGN MANUAL REFERENCE 8-H BOND QUANTITIES WORKSHEET Site Improvement Bond Quantity WorksheetOriginal bond computations prepared by:Name:Date:PE Registration Number:Tel. #:Firm Name:Address:Project No: Stabilization/Erosion Sediment Control (ESC) (A)Existing Right-of-Way Improvements (B)Future Public Road Improvements & Drainage Facilities (C)Private Improvements (D)Construction Bond* Amount (A+B+C+D) = TOTAL (T)Minimum bond* amount is $1000.Maintenance/Defect Bond* TotalNAME OF PERSON PREPARING BOND* REDUCTION:Date:* NOTE:The word "bond" as used in this document means any financial guarantee acceptable to the City of Renton.** NOTE: All prices include labor, equipment, materials, overhead and profit. Prices are from RS Means data adjusted for the Seattle areaor from local sources if not included in the RS Means database.REQUIRED BOND* AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY RDSD-$ -$ -$ (B+C) x 0.20 =-$ ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTSPERFORMANCE BOND*,**AMOUNTPUBLIC ROAD & DRAINAGE MAINTENANCE/DEFECT BOND*,**-$ -$ Page 1 of 1REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateRight-of-Way Road Improvements Improvements & Drainage FacilitiesQuant.Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete CostGENERAL ITEMSNo.Backfill & Compaction- embankment GI - 1 5.62$ CY0.00 0.00 0.00 0.00Backfill & Compaction- trench GI - 2 8.53$ CY0.00 0.00 0.00 0.00Clear/Remove Brush, by hand GI - 3 0.36$ SY 0.00 0.00 0.00 0.00Clearing/Grubbing/Tree Removal GI - 4 8,876.16$ Acre 0.00 0.00 0.00 0.00Excavation - bulk GI - 5 1.50$ CY0.00 0.00 0.00 0.00Excavation - Trench GI - 6 4.06$ CY0.00 0.00 0.00 0.00Fencing, cedar, 6' high GI - 7 18.55$ LF 0.00 0.00 0.00 0.00Fencing, chain link, vinyl coated, 6' high GI - 8 13.44$ LF 0.00 0.00 0.00 0.00Fencing, chain link, gate, vinyl coated, 20GI - 9 1,271.81$ Each 0.00 0.00 0.00 0.00Fencing, split rail, 3' high GI - 10 12.12$ LF 0.00 0.00 0.00 0.00Fill & compact - common barrow GI - 11 22.57$ CY0.00 0.00 0.00 0.00Fill & compact - gravel base GI - 12 25.48$ CY0.00 0.00 0.00 0.00Fill & compact - screened topsoil GI - 13 37.85$ CY0.00 0.00 0.00 0.00Gabion, 12" deep, stone filled mesh GI - 14 54.31$ SY 0.00 0.00 0.00 0.00Gabion, 18" deep, stone filled mesh GI - 15 74.85$ SY 0.00 0.00 0.00 0.00Gabion, 36" deep, stone filled mesh GI - 16 132.48$ SY 0.00 0.00 0.00 0.00Grading, fine, by hand GI - 17 2.02$ SY 0.00 0.00 0.00 0.00Grading, fine, with grader GI - 18 0.95$ SY 0.00 0.00 0.00 0.00Monuments, 3' long GI - 19 135.13$ Each 0.00 0.00 0.00 0.00Sensitive Areas Sign GI - 20 2.88$ Each 0.00 0.00 0.00 0.00Sodding, 1" deep, sloped ground GI - 21 7.46$ SY 0.00 0.00 0.00 0.00Surveying, line & grade GI - 22 788.26$ Day0.00 0.00 0.00 0.00Surveying, lot location/lines GI - 23 1,556.64$ Acre 0.00 0.00 0.00 0.00Traffic control crew ( 2 flaggers ) GI - 24 85.18$ HR0.00 0.00 0.00 0.00Trail, 4" chipped wood GI - 25 7.59$ SY 0.00 0.00 0.00 0.00Trail, 4" crushed cinder GI - 26 8.33$ SY 0.00 0.00 0.00 0.00Trail, 4" top course GI - 27 8.19$ SY 0.00 0.00 0.00 0.00Wall, retaining, concrete GI - 28 44.16$ SF 0.00 0.00 0.00 0.00Wall, rockery GI - 29 9.49$ SF 0.00 0.00 0.00 0.00Page 2 of 7 SUBTOTAL 0.00 0.00 0.00 0.00Quantity Completed (Bond Reduction)*REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateBond Reduction*Right-of-wayRoad Improvements Improvements & Drainage FacilitiesQuant.Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete CostROAD IMPROVEMENTNo.AC Grinding, 4' wide machine < 1000sy RI - 1 23.00$ SY 0.00 0.00 0.00 0.00AC Grinding, 4' wide machine 1000-2000sRI - 2 5.75$ SY 0.00 0.00 0.00 0.00AC Grinding, 4' wide machine > 2000sy RI - 3 1.38$ SY 0.00 0.00 0.00 0.00AC Removal/Disposal/Repair RI - 4 41.14$ SY 0.00 0.00 0.00 0.00Barricade, type I RI - 5 30.03$ LF 0.00 0.00 0.00 0.00Barricade, type III ( Permanent ) RI - 6 45.05$ LF 0.00 0.00 0.00 0.00Curb & Gutter, rolled RI - 7 13.27$ LF 0.00 0.00 0.00 0.00Curb & Gutter, vertical RI - 8 9.69$ LF 0.00 0.00 0.00 0.00Curb and Gutter, demolition and disposal RI - 9 13.58$ LF 0.00 0.00 0.00 0.00Curb, extruded asphalt RI - 10 2.44$ LF 0.00 0.00 0.00 0.00Curb, extruded concrete RI - 11 2.56$ LF 0.00 0.00 0.00 0.00Sawcut, asphalt, 3" depth RI - 12 1.85$ LF 0.00 0.00 0.00 0.00Sawcut, concrete, per 1" depth RI - 13 1.69$ LF 0.00 0.00 0.00 0.00Sealant, asphalt RI - 14 0.99$ LF 0.00 0.00 0.00 0.00Shoulder, AC, ( see AC road unit price ) RI - 15 -$ SY 0.00 0.00 0.00 0.00Shoulder, gravel, 4" thick RI - 16 7.53$ SY 0.00 0.00 0.00 0.00Sidewalk, 4" thick RI - 17 30.52$ SY 0.00 0.00 0.00 0.00Sidewalk, 4" thick, demolition and disposaRI - 18 27.73$ SY 0.00 0.00 0.00 0.00Sidewalk, 5" thick RI - 19 34.94$ SY 0.00 0.00 0.00 0.00Sidewalk, 5" thick, demolition and disposaRI - 20 34.65$ SY 0.00 0.00 0.00 0.00Sign, handicap RI - 21 85.28$ Each 0.00 0.00 0.00 0.00Striping, per stall RI - 22 5.82$ Each 0.00 0.00 0.00 0.00Striping, thermoplastic, ( for crosswalk ) RI - 23 2.38$ SF 0.00 0.00 0.00 0.00Striping, 4" reflectorized line RI - 24 0.25$ LF 0.00 0.00 0.00 0.00Page 3 of 7 SUBTOTAL 0.00 0.00 0.00 0.00REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateBond Reduction*Right-of-wayRoad Improvements Improvements & Drainage FacilitiesQuant.Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete CostROAD SURFACING (4" Rock = 2.5 base & 1.5" top course) For '93 KCRS ( 6.5" Rock= 5" base & 1.5" top course)For KCRS '93, (additional 2.5" base) add: RS - 1 3.60$ SY 0.00 0.00 0.00 0.00AC Overlay, 1.5" AC RS - 2 7.39$ SY 0.00 0.00 0.00 0.00AC Overlay, 2" AC RS - 3 8.75$ SY 0.00 0.00 0.00 0.00AC Road, 2", 4" rock, First 2500 SY RS - 4 17.24$ SY 0.00 0.00 0.00 0.00AC Road, 2", 4" rock, Qty. over 2500SY RS - 5 13.36$ SY 0.00 0.00 0.00 0.00AC Road, 3", 4" rock, First 2500 SY RS - 6 19.69$ SY 0.00 0.00 0.00 0.00AC Road, 3", 4" rock, Qty. over 2500 SY RS - 7 15.81$ SY 0.00 0.00 0.00 0.00AC Road, 5", First 2500 SY RS - 8 14.57$ SY 0.00 0.00 0.00 0.00AC Road, 5", Qty. Over 2500 SY RS - 9 13.94$ SY 0.00 0.00 0.00 0.00AC Road, 6", First 2500 SYRS - 1016.76$ SY 0.00 0.00 0.00 0.00AC Road, 6", Qty. Over 2500 SYRS - 1116.12$ SY 0.00 0.00 0.00 0.00Asphalt Treated Base, 4" thickRS - 129.21$ SY 0.00 0.00 0.00 0.00Gravel Road, 4" rock, First 2500 SYRS - 1311.41$ SY 0.00 0.00 0.00 0.00Gravel Road, 4" rock, Qty. over 2500 SYRS - 147.53$ SY 0.00 0.00 0.00 0.00PCC Road, 5", no base, over 2500 SYRS - 1521.51$ SY 0.00 0.00 0.00 0.00PCC Road, 6", no base, over 2500 SYRS - 1621.87$ SY 0.00 0.00 0.00 0.00Thickened EdgeRS - 176.89$ LF 0.00 0.00 0.00 0.00Page 4 of 7 SUBTOTAL 0.00 0.00 0.00 0.00REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateBond Reduction*Right-of-wayRoad Improvements Improvements & Drainage FacilitiesQuant.Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete CostDRAINAGE (CPP = Corrugated Plastic Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.Access Road, R/D D - 1 16.74$ SY 0.00 0.00 0.00 0.00Bollards - fixed D - 2 240.74$ Each 0.00 0.00 0.00 0.00Bollards - removable D - 3 452.34$ Each 0.00 0.00 0.00 0.00* (CBs include frame and lid)CB Type I D - 4 1,257.64$ Each 0.00 0.00 0.00 0.00CB Type IL D - 5 1,433.59$ Each 0.00 0.00 0.00 0.00CB Type II, 48" diameter D - 6 2,033.57$ Each 0.00 0.00 0.00 0.00 for additional depth over 4' D - 7 436.52$ FT 0.00 0.00 0.00 0.00CB Type II, 54" diameter D - 8 2,192.54$ Each 0.00 0.00 0.00 0.00 for additional depth over 4' D - 9 486.53$ FT 0.00 0.00 0.00 0.00CB Type II, 60" diameter D - 10 2,351.52$ Each 0.00 0.00 0.00 0.00 for additional depth over 4' D - 11 536.54$ FT 0.00 0.00 0.00 0.00CB Type II, 72" diameter D - 12 3,212.64$ Each 0.00 0.00 0.00 0.00 for additional depth over 4' D - 13 692.21$ FT 0.00 0.00 0.00 0.00Through-curb Inlet Framework (Add) D - 14 366.09$ Each 0.00 0.00 0.00 0.00Cleanout, PVC, 4" D - 15 130.55$ Each 0.00 0.00 0.00 0.00Cleanout, PVC, 6" D - 16 174.90$ Each 0.00 0.00 0.00 0.00Cleanout, PVC, 8" D - 17 224.19$ Each 0.00 0.00 0.00 0.00Culvert, PVC, 4" D - 18 8.64$ LF 0.00 0.00 0.00 0.00Culvert, PVC, 6" D - 19 12.60$ LF 0.00 0.00 0.00 0.00Culvert, PVC, 8" D - 20 13.33$ LF 0.00 0.00 0.00 0.00Culvert, PVC, 12" D - 21 21.77$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 8" D - 22 17.25$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 12" D - 23 26.45$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 15" D - 24 32.73$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 18" D - 25 37.74$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 24" D - 26 53.33$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 30" D - 27 71.45$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 36" D - 28 112.11$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 48" D - 29 140.83$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 60" D - 30 235.45$ LF 0.00 0.00 0.00 0.00Culvert, CMP, 72" D - 31 302.58$ LF 0.00 0.00 0.00 0.00Page 5 of 7 SUBTOTAL 0.00 0.00 0.00 0.00REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateBond Reduction*Right-of-wayRoad Improvements ImprovementsDRAINAGE CONTINUED & Drainage FacilitiesQuant.No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Complete CostCulvert, Concrete, 8" D - 32 21.02$ LF 0 0 0 0Culvert, Concrete, 12" D - 33 30.05$ LF 0 0 0 0Culvert, Concrete, 15" D - 34 37.34$ LF 0 0 0 0Culvert, Concrete, 18" D - 35 44.51$ LF 0 0 0 0Culvert, Concrete, 24" D - 36 61.07$ LF 0 0 0 0Culvert, Concrete, 30" D - 37 104.18$ LF 0 0 0 0Culvert, Concrete, 36" D - 38 137.63$ LF 0 0 0 0Culvert, Concrete, 42" D - 39 158.42$ LF 0 0 0 0Culvert, Concrete, 48" D - 40 175.94$ LF 0 0 0 0Culvert, CPP, 6" D - 41 10.70$ LF 0 0 0 0Culvert, CPP, 8" D - 42 16.10$ LF 0 0 0 0Culvert, CPP, 12" D - 43 20.70$ LF 0 0 0 0Culvert, CPP, 15" D - 44 23.00$ LF 0 0 0 0Culvert, CPP, 18" D - 45 27.60$ LF 0 0 0 0Culvert, CPP, 24" D - 46 36.80$ LF 0 0 0 0Culvert, CPP, 30" D - 47 48.30$ LF 0 0 0 0Culvert, CPP, 36" D - 48 55.20$ LF 0 0 0 0Ditching D - 49 8.08$ CY00 0 0Flow Dispersal Trench (1,436 base+) D - 50 25.99$ LFFrench Drain (3' depth) D - 51 22.60$ LF 0 0 0 0Geotextile, laid in trench, polypropylene D - 52 2.40$ SY 0 0 0 0Infiltration pond testing D - 53 74.75$ HR00 0 0Mid-tank Access Riser, 48" dia, 6' deep D - 54 1,605.40$ Each 0 0 0 0Pond Overflow SpillwayD - 55 14.01$ SY 0 0 0 0Restrictor/Oil Separator, 12" D - 56 1,045.19$ Each 0 0 0 0Restrictor/Oil Separator, 15" D - 57 1,095.56$ Each 0 0 0 0Restrictor/Oil Separator, 18" D - 58 1,146.16$ Each 0 0 0 0Riprap, placed D - 59 39.08$ CY00 0 0Tank End Reducer (36" diameter) D - 60 1,000.50$ Each 0 0 0 0Trash Rack, 12" D - 61 211.97$ Each 0 0 0 0Trash Rack, 15" D - 62 237.27$ Each 0 0 0 0Trash Rack, 18" D - 63 268.89$ Each 0 0 0 0Trash Rack, 21" D - 64 306.84$ Each 0 0 0 0Page 6 of 7 SUBTOTAL00 0 0REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 Site Improvement Bond Quantity WorksheetExisting Future Public PrivateBond Reduction*Right-of-wayRoad Improvements Improvements & Drainage FacilitiesQuant.Unit Price Unit Quant. Price Quant. Cost Quant. Cost Complete CostPARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrow PL - 1 15.84$ SY 0 0 0 02" AC, 1.5" top course & 2.5" base coursPL - 2 17.24$ SY 0 0 0 04" select borrow PL - 3 4.55$ SY 0 0 0 01.5" top course rock & 2.5" base course PL - 4 11.41$ SY 0 0 0 0WRITE-IN-ITEMS(Such as detention/water quality vaults.)No.WI - 1 Each 0 0.00 0.00 0.00WI - 2 SY 0 0.00 0.00 0.00WI - 3 CY0 0.00 0.00 0.00WI - 4 LF 0 0.00 0.00 0.00WI - 5 FT 0 0.00 0.00 0.00WI - 6 0 0.00 0.00 0.00WI - 7 0 0.00 0.00 0.00WI - 8 0 0.00 0.00 0.00WI - 9 0 0.00 0.00 0.00WI - 100 0.00 0.00 0.00SUBTOTAL 0.00 0.00 0.00 0.00SUBTOTAL (SUM ALL PAGES):0.00 0.00 0.00 0.0030% CONTINGENCY & MOBILIZATION:0.00 0.00 0.00 0.00 GRANDTOTAL: 0.00 0.00 0.00 0.00COLUMN: B C D EPage 7 of 7REF 8-H BOND QUANTITY WORKSHEET.xlsUnit prices updated: 2/12/02Version: 4/22/02Report Date: 1/19/2010 This page intentionally left blank. Appendix H Operations and Maintenance Manual The following manual includes a brief description of each facility and component requiring periodic maintenance at the project area. It also details the recommended frequency of maintenance activities and refers to the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities. Facility Description Recommended Frequency of Maintenance Detention Pond The proposed stormwater detention pond is located along the southeastern corner of the substation. It is used to control flow rates exiting the proposed facility and prevent downstream erosion. Perform maintenance tasks listed in No. 1 – Detention Ponds of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities after significant storm events. Control Structure Control structures are placed within or adjacent to stormwater detention ponds and are the facilities which restrict runoff from exiting the stormwater detention pond. Perform maintenance tasks listed in No. 4 – Control Structure / Flow Restrictor of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities after significant storm events. Conveyance Pipes Conveyance pipes are placed within the substation and are used to convey water to the proposed stormwater detention pond. Perform maintenance tasks listed in No. 6 – Conveyance Pipes and Ditches of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities after significant storm events. Debris Barriers A debris barrier is placed within the stormwater detention pond at the inlet to the control structure. This prevents trash and other foreign objects from entering the structure and damaging or blocking it. Perform maintenance tasks listed in No. 7 – Debris Barries of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities after significant storm events. Fencing Fencing is placed around the perimeter of the stormwater detention pond and substation to prevent unauthorized individuals from entering the facilities. Perform maintenance tasks listed in No. 9 – Fencing of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities during all site visits. Access Roads An access road along the southern side of the substation is used to gain vehicle access to the site. Perform maintenance tasks listed in No. 12 – Access Roads of the Maintenance Requirements for Flow Control, Conveyance, and WQ Facilities after significant storm events. KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 1/9/2009 KING COUNTY, WASHINGTON SURFACE WATER DESIGN MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE AND WQ FACILITIES KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-1 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES This appendix contains the maintenance requirements for the following typical stormwater control facilities and components: No. 1 – Detention Ponds (p. A-2) No. 2 – Infiltration Facilities (p. A-3) No. 3 – Detention Tanks and Vaults (p. A-5) No. 4 – Control Structure/Flow Restrictor (p. A-7) No. 5 – Catch Basins and Manholes (p. A-9) No. 6 – Conveyance Pipes and Ditches (p. A-11) No. 7 – Debris Barriers (e.g., Trash Racks) (p. A-12) No. 8 – Energy Dissipaters (p. A- 13) No. 9 – Fencing (p. A-14) No. 10 – Gates/Bollards/Access Barriers (p. A-15) No. 11 – Grounds (Landscaping) (p. A-16) No. 12 – Access Roads (p. A-17) No. 13 – Basic Biofiltration Swale (grass) (p. A-18) No. 14 – Wet Biofiltration Swale (p. A-19) No. 15 – Filter Strip (p. A-20) No. 16 – Wetpond (p. A-21) No. 17 – Wetvault (p. A-23) No. 18 – Stormwater Wetland (p. A-24) No. 19 – Sand Filter Pond (p. A-26) No. 20 – Sand Filter Vault (p. A-28) No. 21 – Stormfilter (Cartridge Type) (p. A-30) No. 22 – Baffle Oil/Water Separator (p. A-32) No. 23 – Coalescing Plate Oil/Water Separator (p. A-33) No. 24 – Catch Basin Insert (p. A-35) APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-2 NO. 1 – DETENTION PONDS Maintenance Component Defect or Problem Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. 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. Top or Side Slopes of Dam, 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. 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. Storage Area Liner damaged (If Applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. 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. Inlet/Outlet Pipe. Damaged 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. Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. 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 on the spillway. Spillway restored to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-3 NO. 2 – INFILTRATION FACILITIES Maintenance Component Defect or Problem Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. 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. Infiltration Pond, Top or Side Slopes of Dam, 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. 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. 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. Infiltration Tank Structure 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-4 NO. 2 – INFILTRATION FACILITIES Maintenance Component Defect or Problem Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed 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. Inlet/Outlet Pipes Damaged 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. 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 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 and covers access opening completely. Large access doors/plate 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 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 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. 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. Infiltration Pond Emergency Overflow Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-5 NO. 3 – DETENTION TANKS AND VAULTS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non-floatables). No trash or debris in vault. Tank or Vault Storage Area Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. 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. Tank Structure 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. 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. 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. Inlet/Outlet Pipes Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-6 NO. 3 – DETENTION TANKS AND VAULTS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 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 and covers access opening completely. Large access doors/plate 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. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-7 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure 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 structure. Trash and debris Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. 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. Damage to frame and/or top slab 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 wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks in walls or bottom 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 structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure 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 structure 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. Structure Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. FROP-T Section Damage Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing Cleanout gate is missing. Replace cleanout gate. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Damaged or missing Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Orifice Plate Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Obstructions Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Overflow Pipe Deformed or damaged lip Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design 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. Inlet/Outlet Pipe Damaged 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. 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 Metal Grates (If Applicable) Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. 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. Manhole Cover/Lid 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-9 NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Sediment 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 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. Trash and debris Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. 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. Damage to frame and/or top slab 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 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 structurally sound. Cracks in walls or bottom 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. Structure 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. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-10 NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed 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 Metal Grates (Catch Basins) Damaged or missing Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. 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. Manhole Cover/Lid 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-11 NO. 6 – CONVEYANCE PIPES AND DITCHES Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/roots 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. Pipes Damaged 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. 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Vegetation 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. Ditches 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-12 NO. 7 – DEBRIS BARRIERS (E.G., TRASH RACKS) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed. Trash and debris Trash or debris plugging more than 20% of the area of the barrier. Barrier clear to receive capacity flow. Site Sediment accumulation Sediment accumulation of greater than 20% of the area of the barrier Barrier clear to receive capacity flow. Structure Cracked broken or loose Structure which bars attached to is damaged - pipe is loose or cracked or concrete structure is cracked, broken of loose. Structure barrier attached to is sound. Bar spacing Bar spacing exceeds 6 inches. Bars have at most 6 inche spacing. Bars are bent out of shape more than 3 inches. Bars in place with no bends more than ¾ inch. Bars are missing or entire barrier missing. Bars in place according to design. Bars Damaged or missing bars Bars are loose and rust is causing 50% deterioration to any part of barrier. Repair or replace barrier to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-13 NO. 8 – ENERGY DISSIPATERS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed. Trash and debris Trash and/or debris accumulation. Dissipater clear of trash and/or debris. 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. 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. 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. Dispersion Trench Receiving area over- saturated Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Damaged mesh Mesh of gabion broken, twisted or deformed so structure is weakened or rock may fall out. Mesh is intact, no rock missing. Corrosion 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. Gabions Missing rock Any rock missing that could cause gabion to loose structural integrity. No rock missing. 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. Manhole/Chamber 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-14 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. 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. Wood Posts, Boards and Cross Members 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. 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. Damaged parts 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. Metal Posts, Rails and Fabric 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-15 NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed 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. Damaged or missing members 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. Chain Link Fencing 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. 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. Bar Gate Support post damaged Support post does not hold cross bar up. Cross bar held up preventing vehicle access into facility. Damaged or missing Bollard broken, missing, does not fit into support hole or hinge broken or missing. No access for motorized vehicles to get into facility. Bollards Does 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. Dislodged Boulders not located to prevent motorized vehicle access. No access for motorized vehicles to get into facility. Boulders Circumvented Motorized vehicles going around or between boulders. No access for motorized vehicles to get into facility. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-16 NO. 11 – GROUNDS (LANDSCAPING) Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Trash or litter 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Hazard 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. 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 and Shrubs Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-17 NO. 12 – ACCESS ROADS Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed 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. Trash and debris 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. Any obstruction which reduces clearance above road surface to less than 14 feet. Roadway overhead clear to 14 feet high. Site Blocked roadway 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. Erosion, settlement, potholes, soft spots, ruts Any surface defect which hinders or prevents maintenance access. Road drivable by maintenance vehicles. Road Surface Vegetation on road surface Trees or other vegetation prevent access to facility by maintenance vehicles. Maintenance vehicles can access facility. 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. Shoulders and Ditches 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. 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. Modular Grid Pavement Damaged or missing Access surface compacted because of broken on missing modular block. Access road surface restored so road infiltrates. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-18 NO. 13 – BASIC BIOFILTRATION SWALE (GRASS) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Any trash and/or debris accumulated on the bioswale site. No trash or debris on the bioswale site. 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. 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 accumulation 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. Grass too tall Grass excessively tall (greater than 10 inches), grass is thin or nuisance weeds and other vegetation has taken over. Grass is between 3 and 4 inches tall, thick and healthy. No clippings left in swale. No nuisance vegetation present. Excessive shade Grass growth is poor because sunlight does not reach swale. Health 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. Swale Section 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. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-19 NO. 14 – WET BIOFILTRATION SWALE Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Trash and debris Any trash and/or debris accumulated at the site. No trash or debris at the site. 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. Sediment accumulation Sediment depth exceeds 2 inches in 10% of the swale treatment area. No sediment deposits in treatment area. 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. Water depth Water not retained to a depth of about 4 inches during the wet season. Water depth of 4 inches through out swale for most of wet season. Vegetation ineffective Vegetation sparse, does not provide adequate filtration or crowded out by very dense clumps of cattail or nuisance vegetation. Wetland vegetation fully covers bottom of swale and no cattails or nuisance vegetation present. Swale Section Insufficient water Wetland vegetation dies due to lack of water. Wetland vegetation remains healthy (may require converting to grass lined bioswale Flow Spreader Concentrated flow Flow from spreader not uniformly distributed across entire swale width. Flows are spread evenly over entire swale width. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-20 NO. 15 – FILTER STRIP Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Trash and debris Any trash and debris accumulated on the filter strip site. Filter strip site free of any trash or debris 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. Sediment accumulation Sediment accumulation on grass exceeds 2 inches depth. No sediment deposits in treatment area. 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. Grass too tall Grass excessively tall (greater than 10 inches), grass is thin or nuisance weeds and other vegetation has taken over. Grass is between 3 and 4 inches tall, thick and healthy. No clippings left in swale. No nuisance vegetation present. Grass Strip Vegetation ineffective Grass has died out, become excessively tall (greater than 10 inches) or nuisance vegetation is taking over. Grass is healthy, less than 9 inches high and no nuisance vegetation present. Flow Spreader Concentrated flow Flow from spreader not uniformly distributed across entire swale width. Flows are spread evenly over entire swale width. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-21 NO. 16 – WETPOND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed 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 County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. 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. Side Slopes of Dam, Berm, internal berm or Embankment 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. Top or Side Slopes of Dam, Berm, internal berm or Embankment Irregular surface on internal berm Top of berm not uniform and level. Top of berm graded to design elevation. 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. Water level (first wetpool cell) First cell empty, doesn't hold water. Water retained in first cell for most of the year. Pond Areas 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.) Inoperable valve Valve will not open and close. Valve opens and closes normally. Gravity Drain 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. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-22 NO. 16 – WETPOND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed 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. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-23 NO. 17 – WETVAULT Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Trash and debris Any trash and debris accumulated in vault (includes floatables and non-floatables). No trash or debris in vault. Sediment accumulation Sediment accumulation in vault bottom exceeds the depth of the sediment zone plus 6 inches. No sediment in vault. Treatment Area 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 wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks, vault does not retain water or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure or baffle cannot be removed. Repair or replace baffles or walls to specifications. Vault Structure Ventilation Ventilation area blocked or plugged. No reduction of ventilation area exists. 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. Inlet/Outlet Pipe Damaged 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. Inoperable valve Valve will not open and close. Valve opens and closes normally. Gravity Drain Valve won’t seal Valve does not seal completely. Valve completely seals closed. Access cover/lid damaged or difficult to open Access cover/lid cannot be easily opened by one person. Corrosion/deformation of cover/lid. Access cover/lid can be opened by one person. 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. Access doors/plate has gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-24 NO. 18 – STORMWATER WETLAND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. 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. Side Slopes of Dam, Berm, internal berm or Embankment 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. Top or Side Slopes of Dam, Berm, internal berm or Embankment Irregular surface on internal berm Top of berm not uniform and level. Top of berm graded flat to design elevation. Sediment accumulation (first cell/forebay) Sediment accumulations in pond bottom that exceeds the depth of sediment storage (1 foot) plus 6 inches. Sediment storage contains no sediment. Sediment accumulation (wetland cell) Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth. Liner damaged (If Applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Water level (first cell/forebay) Cell does not hold 3 feet of water year round. 3 feet of water retained year round. Water level (wetland cell) Cell does not retain water for at least 10 months of the year or wetland plants are not surviving. Water retained at least 10 months of the year or wetland plants are surviving. Algae mats (first cell/forebay) 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.) Pond Areas Vegetation Vegetation dead, dying, or overgrown (cattails) or not meeting original planting specifications. Plants in wetland cell surviving and not interfering with wetland function. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-25 NO. 18 – STORMWATER WETLAND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Inoperable valve Valve will not open and close. Valve opens and closes normally. Gravity Drain Valve won’t seal Valve does not seal completely. Valve completely seals closed. Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. 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. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-26 NO. 19 – SAND FILTER POND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover (not in the treatment area) Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Sediment accumulation 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. Water level Cell empty, doesn't hold water. Water retained in first cell for most of the year. Pre-Treatment (if applicable) Algae mats 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.) Sediment accumulation Sediment or crust depth exceeds ½-inch over 10 % of surface area of sand filter. No sediment or crust deposit on sand filter that would impede permeability of the filter section. Pond Area Grass (if applicable) Grass becomes excessively tall (greater than 6 inches) or when nuisance weeds and other vegetation start to take over or thatch build up occurs. Mow vegetation and/or remove nuisance vegetation. 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. Side Slopes of Pond 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. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-27 NO. 19 – SAND FILTER POND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Plugging Drawdown of water through the sand filter media, takes longer than 24 hours, and/or flow through the overflow pipes occurs frequently. A sieve analysis of >4% -100 or >2% -200 requires replacing sand filter media. Sand filter media surface is aerated and drawdown rate is normal. Prolonged flows Sand is saturated for prolonged periods of time (several weeks) and does not dry out between storms due to continuous base flow or prolonged flows from detention facilities. Excess flows bypassed or confined to small portion of filter media surface. Short circuiting Flows become concentrated over one section of the sand filter rather than dispersed or drawdown rate of pool exceeds 12 inches per hour. Flow and percolation of water through the sand filter is uniform and dispersed across the entire filter area and drawdown rate is normal. Sand Filter Media Media thickness Sand thickness is less than 6 inches. Rebuild sand thickness to a minimum of 6 inches and preferably to 18 inches. Underdrains and Clean-Outs Sediment/debris Underdrains or clean-outs partially plugged or filled with sediment and/or debris. Junction box/cleanout wyes not watertight. Underdrains and clean-outs free of sediment and debris and are watertight. 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. Inlet/Outlet Pipe Damaged 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. Rock Pad Missing or out of place Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil. Rock pad restored to design standards. Flow spreader Concentrated flow Flow from spreader not uniformly distributed across sand filter. Flows spread evenly over sand filter. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-28 NO. 20 – SAND FILTER VAULT Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to County personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where County 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. Site Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Pre-Treatment Chamber Sediment accumulation Sediment accumulation exceeds the depth of the sediment zone plus 6 inches. Sediment storage contains no sediment. Sediment accumulation Sediment depth exceeds ½-inch on sand filter media. Sand filter freely drains at normal rate. Trash and debris Trash and debris accumulated in vault (floatables and non-floatables). No trash or debris in vault. Plugging Drawdown of water through the sand filter media, takes longer than 24 hours, and/or flow through the overflow pipes occurs frequently. A sieve analysis of >4% -100 or >2% -200 requires replacing sand filter media. Sand filter media drawdown rate is normal. Sand Filter Media Short circuiting Seepage or flow occurs along the vault walls and corners. Sand eroding near inflow area. Cleanout wyes are not watertight. Sand filter media section re-laid and compacted along perimeter of vault to form a semi-seal. Erosion protection added to dissipate force of incoming flow and curtail erosion. Damaged to walls, 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 replaced or repaired to provide complete sealing of the structure. Vault Structure Ventilation Ventilation area blocked or plugged. No reduction of ventilation area exists. Underdrains and Cleanouts Sediment/debris Underdrains or clean-outs partially plugged, filled with sediment and/or debris or not watertight. Underdrains and clean-outs free of sediment and debris and sealed. 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. Inlet/Outlet Pipe Damaged 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 FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-29 NO. 20 – SAND FILTER VAULT Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 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 and covers access opening completely. Large access doors/plate 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. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-30 NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Contaminants and pollution Any evidence of contaminants or pollution such as oils, 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. Site Life cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed. Sediment on vault floor Greater than 2 inches of sediment. Vault is free of sediment. Sediment on top of cartridges Greater than ½ inch of sediment. Vault is free of sediment. Vault Treatment Area Multiple scum lines above top of cartridges Thick or multiple scum lines above top of cartridges. Probably due to plugged canisters or underdrain manifold. Cause of plugging corrected, canisters replaced if necessary. Damage to wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or qualified inspection personnel determines the vault is not structurally sound. Vault replaced or repaired to design specifications. Vault Structure Baffles damaged Baffles corroding, cracking warping, and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specification. Standing water in vault 9 inches or greater of static water in the vault for more than 24 hours following a rain event and/or overflow occurs frequently. Probably due to plugged filter media, underdrain or outlet pipe. No standing water in vault 24 hours after a rain event. Filter Media Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and Clean-Outs Sediment/debris Underdrains or clean-outs partially plugged or filled with sediment and/or debris. Underdrains and clean-outs free of sediment and debris. 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. Inlet/Outlet Pipe Damaged 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. 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. Access Manhole 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. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-31 NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover 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. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-32 NO. 22 – BAFFLE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Site Contaminants and pollution Floating oil in excess of 1 inch in first chamber, any oil in other chambers or other contaminants of any type in any chamber. No contaminants present other than a surface oil film. Sediment accumulation Sediment accumulates exceeds 6 inches in the vault. No sediment in the vault. Discharge water not clear Inspection of discharge water shows obvious signs of poor water quality- effluent discharge from vault shows thick visible sheen. Effluent discharge is clear. Trash or debris accumulation Any trash and debris accumulation in vault (floatables and non-floatables). Vault is clear of trash and debris. Vault Treatment Area Oil accumulation Oil accumulations that exceed 1 inch, at the surface of the water in the oil/water separator chamber. No visible oil depth on water. Damage to Wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch or evidence of soil particles entering the structure through the cracks, or maintenance/inspection personnel determines that the vault is not structurally sound. Vault replaced or repaired to design specifications. Vault Structure Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure as determined by maintenance inspection personnel. Repair or replace baffles to specifications. Inoperable valve Valve will not open and close. Valve opens and closes normally. Gravity Drain Valve won’t seal Valve does not seal completely. Valve completely seals closed. 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. Inlet/Outlet Pipe Damaged 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. 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. 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 and cover access opening completely. Large access doors/plate Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or cover/lid. Lifting rings sufficient to lift or remove cover/lid. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-33 NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Site Contaminants and pollution Floating oil in excess of 1 inch in first chamber, any oil in other chambers or other contaminants of any type in any chamber. No contaminants present other than a surface oil film. Sediment accumulation in the forebay Sediment accumulation of 6 inches or greater in the forebay. No sediment in the forebay. Discharge water not clear Inspection of discharge water shows obvious signs of poor water quality - effluent discharge from vault shows thick visible sheen. Repair function of plates so effluent is clear. Trash or debris accumulation Trash and debris accumulation in vault (floatables and non-floatables). Trash and debris removed from vault. Vault Treatment Area Oil accumulation Oil accumulation that exceeds 1 inch at the water surface in the in the coalescing plate chamber. No visible oil depth on water and coalescing plates clear of oil. Damaged Plate media broken, deformed, cracked and/or showing signs of failure. Replace that portion of media pack or entire plate pack depending on severity of failure. Coalescing Plates Sediment accumulation Any sediment accumulation which interferes with the operation of the coalescing plates. No sediment accumulation interfering with the coalescing plates. Damage to Wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or maintenance inspection personnel determines that the vault is not structurally sound. Vault replaced or repaired to design specifications. Vault Structure Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specifications. Ventilation Pipes Plugged Any obstruction to the ventilation pipes. Ventilation pipes are clear. Shutoff Valve Damaged or inoperable Shutoff valve cannot be opened or closed. Shutoff valve operates normally. 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. Inlet/Outlet Pipe Damaged 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. 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. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-34 NO. 23 – COALESCING PLATE OIL/WATER SEPARATOR Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed 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 and cover access opening completely. Large access doors/plate 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. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-35 NO. 24 – CATCH BASIN INSERT Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Visible Oil Visible oil sheen passing through media Media inset replaced. Insert does not fit catch basin properly Flow gets into catch basin without going through media. All flow goes through media. Filter media plugged Filter media plugged. Flow through filter media is normal. Oil absorbent media saturated Media oil saturated. Oil absorbent media replaced. Water saturated Catch basin insert is saturated with water, which no longer has the capacity to absorb. Insert replaced. Service life exceeded Regular interval replacement due to typical average life of media insert product, typically one month. Media replaced at manufacturer’s recommended interval. Media Insert Seasonal maintenance When storms occur and during the wet season. Remove, clean and replace or install new insert after major storms, monthly during the wet season or at manufacturer’s recommended interval.