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F_Weston Heights Plat_Technical Information Report_160623
June 20, 2016 Weston Heights Technical Information Report 684 Nile Ave NE, Renton, WA SDA Project #349-004-14 Prepared for: Prospect Development, LLC 2913 5th Avenue NE, Ste. 201 Puyallup, WA 98372 CIVIL ENGINEERING | PROJECT MANAGEMENT | PLANNING 1724 W. Marine View Drive, Suite 140, Everett, WA 98201 | 425.486.6533 | www.sdaengineers.com Weston Heights Technical Information Report Weston Heights Technical Information Report Prepared For: Prospect Development, LLC 2913 5th Avenue NE, Ste. 201 Puyallup, WA 98372 Prepared By: SDA Engineers 1724 West Marine View Drive, Ste 140 Everett, WA 98201 (425) 486-6533 Last save by: Ken McIntyre on 6/20/16 R:\Projects\349 (prospect development)\004-14 (Weston Heights)\Technical\Reports\2016-06-14 TIR\2016-06-20 WH Drainage Report.docm 06-20-16 Weston Heights Technical Information Report TABLE OF CONTENTS SECTION 1 PROJECT OVERVIEW Project Overview Figure 1 – TIR Worksheet Figure 2 – Vicinity Map SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY SECTION 3 OFF-SITE ANALYSIS Task 1 – Study Area Definition & Maps Task 2 – Resource Review Task 3 – Field Inspection Task 4 – Drainage System Description and Problem Descriptions Task 5 – Mitigation of Existing or Potential Problems Appendix 3A – Downstream Analysis Map and Photos Appendix 3B – Resource Review Documents SECTION 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Part A – Existing Site Hydrology Part B – Developed Site Hydrology Part C – Performance Standards Part D – Flow Control System Part E – Water Quality System Part F – Wetland Hydrology Appendix 4A – Flow Control Design Calculations Appendix 4B – Treatment Design Calculations Appendix 4C – Wetland Hydroperiod Calculations SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Appendix 5A – Conveyance Calculations Appendix 5B – Isopluvial Map – 100-yr, 24-hr Precipitation SECTION 6 SPECIAL REPORTS AND STUDIES Appendix 6A – Geotechnical Report Appendix 6B – Olympus Villa LUA 10-090 Appendix 6C – Olympus Villa As-Built Plans SECTION 7 OTHER PERMITS SECTION 8 CSWPPP ANALYSIS AND DESIGN SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT Appendix 9 – Bond Quantity Worksheet SECTION 10 OPERATIONS AND MAINTENANCE MANUAL Weston Heights Technical Information Report SECTION 1 PROJECT OVERVIEW Weston Heights Technical Information Report Project Overview The Weston Heights project proposes the construction of 12 single family lots on two existing parcels totaling approximately 4.55 acres. The project occupies King County Tax Parcel Numbers 1123059092 and 1123059010, and is situated in the northwest quarter of Section 11, Township 23 North, Range 5 East, W.M. More specifically, the project is located on the east side of Nile Ave NE, approximately 0.4 miles of the intersection of Nile Ave and north of NE 4th Street. A vicinity map has been provided as Figure 2 of this document. A central wetland area divides the site into two distinct developable pieces. The wetland area and a surrounding buffer will remain undisturbed, and separate access roads will be provided to each of the two developable areas. The wetland also divides the site into two distinct drainage basin areas, which are referred to in this report as the “West” which will contain nine new single-family lots, and “East” basin which will contain three new single-family lots. The central and eastern portion of the combined subject parcel is largely undisturbed, consisting of native forest trees and shrubs. The western side has previously been cleared and primarily consists of pasture grass and lawn area. The topography of the combined subject parcel slopes moderately from the east and west edges into the existing wetland. The project is contained within a single threshold discharge area, but practically speaking, the central wetland bisects the site into two distinct areas, which will be treated separately for stormwater modeling purposes. The USDA Soil Survey for King county indicates that the site consists of Alderwood gravelly sandy loam, which is generally characterized as glacial till, with moderate runoff rates and low capacity for infiltration. Much discussion involving the Olympus Villa Pond ‘A’ will be found within this text. This is largely due to the fact that this development, Weston Heights, will likely be constructed concurrently with the Weston Heights North development. Although these two developments are likely to be constructed concurrently, they are being designed under separate plat actions. Ultimately, the Weston Height’s stormwater management facilities have been designed to accommodate the Weston Heights North project area. However, the Weston Heights facilities were not able to accommodate the entire Weston Heights North development. It is this reason that the Olympus Villa Pond ‘A’ is mentioned frequently in this text. Surface runoff will be detained through three separate facilities in order to avoid concentration of flows. Surface runoff will be directed to a combined detention pond, and/or a detention vault. Flow control structures are included to match the historic release rates. A flow spreader will service the detention pond on the east, spreading flows overland and ultimately into the wetland. New storm sewer infrastructure will convey storm water from the western detention vault to an existing roadside ditch along the eastern edge of Nile Ave NE. The Olympus Villa Pond ‘A’ flow control structure will be reconfigured to satisfy the historic release rates. This meets the requirements for Full Drainage Review, as described further in Section 4 of this report. Weston Heights Technical Information Report FIGURE 1 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 ________________ ________________ ________________ ________________ ________________ ________________ ________________ Weston Heights Technical Information Report FIGURE 2 VICINITY MAP Date Project No. Drawn Design Figure No. Scale KJM SJR 2015-06-09 349-004-14 WESTON HEIGHTS VICINITYMAP 1"=1000' FIG1.0NPROJECT SITE Weston Heights Technical Information Report SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY Weston Heights Technical Information Report Conditions and Requirements Summary The project proposes more than 2,000 square feet of new impervious surface area, and is subject to the provisions for Full Drainage Review as outlined in the 2009 King County stormwater Design Manual (KCSWDM). Full Drainage Review requires the accommodation of 8 core requirements in addition to 6 special requirements – all of which are listed and discussed below. Core Requirement #1 – Discharge at Natural Location The pre-developed drainage discharge locations will be maintained for post-developed conditions. Drainage improvements consist of implementing new storm sewer infrastructure to utilize two separate facilities – the detention pond serving the eastern developments, and the combined detention vault serving the western developments. The eastern facility will discharge via level spreader into the existing wetland, maintaining the pre-developed surface water discharge location. The western facility will discharge via a new conveyance system into the existing roadside ditch along Nile Ave NE, maintaining the pre-developed surface water discharge location. Those areas directed to Olympus Villa Pond ‘A’ will ultimately maintain their existing discharge location. The Olympus Villa Pond outlets to the south in man-made conveyance until outfalling to the roadside ditch just south of the west basin’s detention facility. Stormwater from the Olympus Villa pond will combine with the stormwater from the west basin facility at this location, which maintains the pre-developed surface water discharge location. Core Requirement #2 – Offsite Analysis A thorough off-site analysis is presented in Section 3 of this report. Core Requirement #3 – Flow Control Flow control of surface runoff for this site is provided via two detention facilities – the detention facility serving the eastern basin, and the combined detention facility serving the western basin. Olympus Villa Pond ‘A’ provides detention for those areas in the future Weston Heights North project that are unable to be accommodated in the east and/or west basin detention facilities. Design calculations for these facilities are contained in Section 4 of this report. Core Requirement #4 – Conveyance System Stormwater conveyance has been analyzed in Section 5 of this report. Core Requirement #5 – Erosion & Sediment Control An erosion and sediment control analysis has been provided in Section 8 of this report. Core Requirement #6 – Maintenance & Operations Maintenance and operations of the proposed storm drainage facilities is addressed in Section 10 of this report. Core Requirement #7 – Financial Guarantees & Liabilities Financial guarantees and liabilities are addressed in Section 9 of this report. Weston Heights Technical Information Report Core Requirement #8 – Water Quality Water quality for surface runoff on the East Basin will be provided via a StormFilter vault. The StormFilter utilizes cartridges to remove suspended solids from the runoff. Roof runoff will be routed around the StormFilter to minimize the required treatment flowrates for the StormFilter. Roof runoff is considered NPGIS (non-pollution generating impervious surface) and does not require treatment if the runoff is separated from pollution generating impervious surface runoff, as is the scenario for this project. Water quality for surface runoff on the West Basin, and for those areas that the existing Olympus Villa Pond ‘A’ receive, will be provided via wetpool. Permanent wetpools allow for settling of solids that are suspended in the stormwater runoff. A discussion of the design methodology and calculations for this feature are provided in Section 4 of this document. SUMMARY OF SPECIAL REQUIREMENTS Special Requirement #1 – Other Adopted Area-Specific Requirements There are no adopted basin plans or area-specific requirements affecting Parcel’s 11023059092 and 11023059010. Therefore, the project is exempt from this requirement. Special Requirement #2 – Flood Hazard Area Delineation The project site and surrounding area is shown on FEMA Flood Insurance Rate Map No. 53033C0982, and is not located within a flood hazard area. Therefore, the project is exempt from this requirement. A portion of the FEMA map referenced above is included in Appendix 3-B of this report. Special Requirement #3 – Flood Protection Facilities The project neither relies on an existing flood protection facility, nor proposes a new flood protection facility, and therefore, is exempt from this requirement. Special Requirement #4 – Source Control This project does not require a commercial building or commercial site development permit, and therefore, is exempt from this requirement. Special Requirement #5 – Oil Control This project does not have high-use site characteristics as defined in KCSWDM Section 1.3.5, and therefore, is exempt from this requirement. Special Requirement #6 – Aquifer Protection Area The project site is shown outside of the extents of Aquifer Protection Area Zone 1, Zone 1 Modified, and Zone 2 on Reference 11-B of the City of Renton Amendments to the 2009 KCSWDM. Therefore, this project is exempt from this requirement. Weston Heights Technical Information Report SECTION 3 OFFSITE ANALYSIS Weston Heights Technical Information Report Task 1 – Study Area Definitions and Maps The project’s study area includes the subject parcel, and a flow path extending approximately 1-mile downstream of the site. An off-site analysis map has been included in Appendix 3A. Task 2 – Resource Review The following documents were reviewed, as prescribed by the 2009 King County Surface Water Design Manual: Adopted Basin Plans There are no adopted basin plans which affect the subject property. Floodplain/Floodway Maps The project site and surrounding area is shown on FEMA Flood Insurance Rate Map No. 53033C0982, and is not located within a flood hazard area. Therefore, the project is exempt from this requirement. A portion of the FEMA map referenced above is included in Appendix 3B of this report. Sensitive Areas Folio Maps The King County Sensitive Areas Folio Maps are outdated, and were not consulted for this project. However, a search for other sensitive area documents was performed, and the site was not to contain or be near a coal mine hazard area, erosion hazard area, steep slope, or landslide hazard area. A wetland area occupies the middle of the site, but will remain undisturbed by the project. Drainage Complaints No documented downstream drainage complaints were located. The preliminary technical information report (prepared by others) also found no relevant drainage complaints. Road Drainage Problems No road drainage problems were located that would be impacted by the project. USDA Soil Survey for King County The USDA Soil Survey for King County indicates that the site is underlain by Alderwood soils, which are generally characterized as a consolidated till, with moderate runoff rates and little capacity for infiltration. A portion of the USDA Soil Survey map is included in Appendix 3B. Wetlands Inventory Mapping A wetland exists near the middle of the project site. Migrating River Studies No migrating river studies were located which affect the subject property. Weston Heights Technical Information Report DOE 303(d) List of Polluted Waters The DOE’s Water Quality Assessment Map tool does not identify any 303(d)-listed waterways in the downstream flowpath within several miles of the site. The project is ultimately tributary to the Cedar River, which is a 303(d) listed waterway at its discharge point to Lake Washington, but this is a substantial distance from the site, and the flow contribution from the project site is expected to be insignificant compared to the full capacity of the river at that point. King County Designated Water Quality Problems King County I-Map does not identify the project site as containing or being tributary to any designated water quality problems. Task 3 – Field Inspection A Level 1 Downstream Analysis was prepared in the preliminary design phase by Core Design, and the photos from that analysis have been provided in Appendix 3A. The project site and downstream flowpath were visited on the afternoon of June 10, 2015 to verify the findings of that downstream analysis. Conditions at the time of the visit were warm and sunny, with no significant precipitation having occurred within the previous few days. No surface runoff was observed at the project site during the site visit. The downstream flowpath for the west side of the project simply follows a road-side ditch which extends southerly along the east side of Nile Ave NE. The ditch is primarily grassed, but has been stabilized with quarry spalls in some locations, and contains a number of culvert crossings beneath various intersections and driveways. The east half of the project falls to the central wetland area, then flows west where it is intercepted by the public storm drainage system in Orcas Ave W. This storm system flows to NE 6th Street, jogs westerly, and then discharges to the road-side ditch in Nile Ave NE. Task 4 – Drainage System Description and Problem Description The west half of the project generally falls toward the west, discharging to the road-side ditch along the east side of Nile Ave. The east half of the project generally falls toward the west, and is collected in the wetland area in the center of the project. Water from this wetland enters an overflow device just north of Orcas Ave W, then is conveyed to the Nile Ave roadside ditch. The outfall from the conveyance downstream of the Olympus Villa Pond ‘A’ is the same as the outfall for the west detention facility. There were no significant erosion or sediment issues identified in the downstream system for the ¼-mile analysis distance. Task 5 – Mitigation of Existing or Potential Problems No significant hydraulic problems were observed at the project site or downstream. With routine maintenance to keep debris clear of the ditch/culverts, the downstream system is expected to continue functioning. Weston Heights Technical Information Report APPENDIX 3A DOWNSTREAM ANALYSIS MAP AND PHOTOS Core Design, Inc. WESTON HEIGHTS Page 6 Level 1 Downstream Analysis Field Investigation A field investigation was completed on May 21, 2014. The temperature was approximately 60 degrees and sunny. The existing site has two residences with gravel driveways and a detached garage. The western quarter of the site is covered in lawn (surrounding the residences and garage) and the remaining site is forested with a wetland in the center of the site. The wetland drains south and overflows into a 12-inch storm drain in the Edenwood Plat which continues south to NE 6th Street. From NE 6th Street, the 12-inch storm drain flows west where it has a confluence with the drainage system on the east side of Nile Avenue NE. Overland flow from the west portion of the site drains west to Nile Avenue NE and drains south in series of grass or rock lined ditches and culverts on the east side of the street. The open channels range from a depth of 1 foot and a width of 4 feet with rock lining on the north end of the site (Picture 1) to a vegetated channel with a depth of 2 feet and width of 3 feet just below the project’s south property line. The ditch and culvert section continues south on the east side of Nile Avenue NE until approximately 300 feet north of NE 4th Pl, where it drains into an 18-inch storm drain and flows south. This is the quarter mile point downstream of the site. The City of Renton provides current storm water information online, using a GIS based system called COR Maps. COR Maps provides information on the type of pipes, manholes and catch basins in the city. Following the pipe flow direction from COR Maps, the 18-inch diameter concrete pipe crosses over to the west side of Nile Avenue just before it intersects with NE 4th street. The pipe then heads west down NE 4th street and crosses to the south side just before Jericho Avenue. The storm water pipe parallels Jericho Avenue running through private property until NE 2nd street. Picture 10 shows the manhole as the pipe crosses from the east side of Jericho Avenue and heads south down the center line of the road. Flow continues south until NE 1st street, where the 36-inch pipe heads west and discharges into Maplewood Creek. Core Design, Inc. WESTON HEIGHTS Page 7 1 – Looking south in drainage ditch along the east side of Nile Avenue next to the site 2 – Looking south along the east side of Nile Avenue into first culvert 3 – Looking south on the east side of Nile Avenue just downstream of site 4 – Looking south along the east side of Nile Avenue just before NE 6th Street Core Design, Inc. WESTON HEIGHTS Page 8 5 – Looking at a concrete pipe junction with water flowing left to right (south) down Nile Avenue 6 – Looking south on the east side of Nile Avenue at the last drainage ditch before pipe flow 7 – Looking south on the east side of Nile Avenue before NE 4th Street 8 – Looking South at the intersection of 4th and Nile Avenue where pipe flow crosses Nile Avenue from left to right (east to west) Core Design, Inc. WESTON HEIGHTS Page 9 9 – Existing man hole looking west on NE 4th street 10 – Existing Man hole looking South down Jericho Avenue 11 – Storm water outlet into Maplewood stream next to Jericho Street 12 – Looking at the downstream flow from Maplewood just after outlet Looking south on Weston Heights Technical Information Report APPENDIX 3B RESOURCE REVIEW DOCUMENTS Soil Map—King County Area, Washington (Weston Heights) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/8/2015 Page 1 of 3526017052602405260310526038052604505260520526017052602405260310526038052604505260520564330564400564470564540564610564680564750564820564890564960 564330 564400 564470 564540 564610 564680 564750 564820 564890 564960 47° 29' 43'' N 122° 8' 45'' W47° 29' 43'' N122° 8' 14'' W47° 29' 29'' N 122° 8' 45'' W47° 29' 29'' N 122° 8' 14'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 100 200 400 600Feet 0 40 80 160 240Meters Map Scale: 1:3,000 if printed on A landscape (11" x 8.5") sheet. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 10, Sep 30, 2014 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 8, 2014—Jul 15, 2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington (Weston Heights) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/8/2015 Page 2 of 3 Map Unit Legend King County Area, Washington (WA633) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgC Alderwood gravelly sandy loam, 8 to 15 percent slopes 5.5 100.0% Totals for Area of Interest 5.5 100.0% Soil Map—King County Area, Washington Weston Heights Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/8/2015 Page 3 of 3 Weston Heights Technical Information Report SECTION 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Weston Heights Technical Information Report Part A – Existing Site Hydrology The project site, including the Weston Heights North development, is effectively split into two distinct basins by a central wetland area. For stormwater modeling purposes, the Weston Heights North project areas are included in this discussion. The separate basins will simply be referred to as “East” and “West”. Both basins ultimately fall toward the southwest. The west basin is intercepted by Nile Avenue, and the east basin discharges to the central wetland area. The central wetland area will be left undisturbed. The west basin, within the Weston Heights project limits, is currently occupied by two existing single family residences. The area north of the west basin, within the Weston Heights North project limits, is currently occupied by a single family residence, a detached garage, a shed, and a Quonset hut. The east basin, within the Weston Heights project limits, is currently forested. The east basin north of the Weston Heights project limits, has been previously developed and is considered pasture. For purposes of the stormwater model, both basins are considered to be forested in the historic condition, as prescribed by the 2009 King County Surface Water Design Manual (KCSWDM). Part B – Developed Site Hydrology The Weston Heights project proposes 12 single family lots with the associated roadways and utilities. The Weston Heights North project, included as part of the east basin, proposes 5 new single family lots, while maintaining the existing lot to the west. Both of the existing drainage basins, east and west, will be preserved in the proposed layout. Nine lots will be constructed in the west basin and three lots will be constructed in the east basin. Runoff from the west basin will be collected and routed to an underground detention/treatment vault, before being released to the public storm drainage system on the east side of Nile Avenue. Runoff from a majority of the east basin will be collected and routed to a detention pond before being released to the wetland in the middle of the site. The remaining runoff generated in the east basin will be either collected and routed north to the Olympus Villa Pond or discharged to the wetland. The Olympus Villa Pond ‘A’ releases to the same ditch, at the same location, as the west detention facility. No wetland impacts are proposed as part of this project. Part C – Performance Standards The project is subject to the “Conservation Flow Control” criteria outlined in Chapter 1 (Core Requirement #3) of the 2009 King County Surface Water Design Manual (KCSWDM). This requires that the developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow. That lot in the Weston Heights North project not being provided flow control will be included as a bypass basin and included as such when modeling the western detention facility. The project is subject to the “Basic Treatment” criteria outlined in Chapter 1 (Core Requirement #8). The goal of this requirement is 80% removal of total suspended solids for a typical rainfall year. Part D – Flow Control System Flow control will be achieved via an underground combined vault in the west basin, an open detention pond in the east basin, and an open combined detention pond in the Olympus Villa development – Pond ‘A’, to the north. The west underground combined vault provides flow control for Weston Heights Lots 1-9, Nile Ave (to the extent of the frontage improvements), and has been oversized to mitigate for two bypass areas; one in the future development to the north (Lot’s 2 and 3), and one on the south west side of the site. The landscaping/yard area on the future developments (Weston Heights North) Lot’s 2 and 3 is not feasibly Weston Heights Technical Information Report routed to the east detention pond, and there is not capacity in Olympus Villa Pond ‘A’. All three of these facilities discharge within the same threshold discharge area (TDA). Therefore, the entire lot areas for Lot 2 and 3 are considered as a portion of the total west basin bypass area. The second west bypass area includes a portion of the frontage improvements along Nile Ave, which is not feasibly routed to the west basin combined facility. Therefore, this area is considered a bypass area. The two bypass areas, represented as the “West Bypass Basin”, have been modeled as bypass against the west basin underground combined facility. These areas have been mitigated for by the oversizing of the west basin combined facility. The east basin detention pond provides flow control for Weston Heights Lots 10-12, Private Road ‘C’, future development Lot #’s 4-6 (entire lot area), as well as the east bypass basin. The frontage improvements along Private Road ‘C’, adjacent NE 7th Pl, is not feasibly routed to the detention pond. Therefore, the pond has been oversized to mitigate for the East Bypass Basin. The Olympus Villa LUA and as-built plans have been included in this report as Appendices 6B, and 6C, respectively. The Olympus Villa Pond ‘A’ was constructed larger than designed, thereby allowing this project’s utilization. The required detention volume of the original design was 36,042-CF. The constructed detention volume, as reported in the as-built plans, is 38,648-CF. This project directs the frontage improvement area (sidewalk/roadway/planter area) along NE 7th Pl (which will occur during the future development’s construction), as well as the impervious areas of Lot 2 and Lot 3, to Olympus Villa Pond ‘A’. The ultimate discharge of Pond ‘A’ is the same point as the discharge for the west underground detention vault. All facilities have been designed using King County Runoff Time Series (KCRTS) stormwater runoff modeling software. Refer to Appendix 4A for “Flow Control Design Calculations”. KCRTS does not have a convenient way to iteratively model irregularly shaped ponds, so the design calculations for the east pond have been approximated by a more prismatic pond shape. A spreadsheet has been provided at the end of the KCRTS calculations comparing the volume of the designed pond (per plans) and the assumed pond (used for the calculations), at 0.5-ft intervals. The spreadsheet shows that the pond used for the modeling calculations provides slightly less volume at each interval, and therefore, provides a conservative design. Part E – Water Quality System Basic treatment for the east basin will be provided via Stormfilter system. Basic treatment for the west basin and those areas sent to Olympus Villa Pond ‘A’ will be provided via permanent wetpool. The west basin underground vault will contain a permanent wetpool in the bottom of the vault, and has room for detention storage in the upper portion of the vault. The permanent wetpool allows for suspended solids to settle out retained runoff once inside the facility. Compensatory pollution generation impervious surface (PGIS) area from Nile Ave, north of the bypass area, will be treated to offset for the PGIS area of the bypass basin not feasibly routed to the facility. The east basin Stormfilter system, upstream of the detention pond, provides removal of suspended solids via cartridges. The roof areas from the future development Lot #’s 3-6, and Weston Heights Lot #’s 10-12 have been routed around the Stormfilter system. The roof areas are considered non-pollution generating impervious surfaces and therefore do not require treatment, given that the runoff does not mix with untreated PGIS runoff, which is the scenario for this project. The Olympus Villa Pond ‘A’ will contain a permanent wetpool in the bottom of the pond, and room for detention storage in the upper portion of the pond. Olympus Villa Pond ‘A’ was constructed larger than designed. The required water quality volume of the original design was 9,881-CF. The constructed water quality volume, as reported in the as-built plans, is 15,479-CF. Weston Heights Technical Information Report Wetpool volumes have been designed using the guidance provided in Section 6.4.1.1 of the 2009 KCSWDM. The Stormfilter system has been designed following the guidance provided in Section 6.5.5.1 of the 2009 KCSWDM. Refer to Appendix 4B for “Water Quality Design Calculations”. Part F – Wetland Hydrology A wetland is located in the central region of the project. This wetland and its surrounding buffer – varying between 50-feet and 56.25-feet for the Weston Heights and Weston Heights North projects, respectively, will remain undisturbed. This wetland area divides the Weston Heights development, immediately south of Weston North, into two separate drainage basins. The separate drainage basins, named West Basin and East Basin, are contained within one single threshold discharge area. The predeveloped conditions would have runoff from the eastern most extents of the Weston Heights North (future development) project, in addition to the buffer area to the north and west, contributing flow to this wetland. The Weston Heights areas that contribute flow to the wetland include the entire East basin and a portion of the West basin. As a result of these two separate projects, Weston Heights North (future development) and Weston Heights, predeveloped runoff will be directed away from the wetland in order to satisfy flow control requirements. In order to satisfy the existing wetland hydroperiod the runoff from the undisturbed Weston Heights North (future development) Lot 1, will be redirected into the wetland via an interceptor dike. The yard/landscape areas on Weston Heights North (future development) Lots 2 and 3 will be allowed to sheet flow into the wetland as well. Refer to Appendix 4C for “Wetland Hydroperiod Calculations”. Weston Heights Technical Information Report APPENDIX 4A FLOW CONTROL DESIGN CALCULATIONS NE 7TH PLNILE AVE NEWEST BASINEAST BASINFUTURE LOT #'S 3-5WESTBYPASSBASINFUTURE LOT #'S 1 & 2EAST BYPASSBASINDateProject No.DrawnDesignSheet:JDAEWJ6/06/16349-004-14DEVELOPED BASIN MAPWESTON HEIGHTSNWEST PROJECT BASINWEST BYPASS BASINEAST PROJECT BASINNOTES:EAST BYPASS BASIN Weston Heights Technical Information Report KCSWDM – SCALE FACTOR Weston Heights Technical Information Report West Basin – Existing Condition Flow Frequency Analysis Time Series File:west-pre.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.185 2 2/09/01 15:00 0.251 1 100.00 0.990 0.045 8 1/05/02 16:00 0.185 2 25.00 0.960 0.126 4 2/28/03 16:00 0.161 3 10.00 0.900 0.047 7 8/26/04 1:00 0.126 4 5.00 0.800 0.116 5 1/05/05 10:00 0.116 5 3.00 0.667 0.093 6 1/18/06 21:00 0.093 6 2.00 0.500 0.161 3 11/24/06 5:00 0.047 7 1.30 0.231 0.251 1 1/09/08 7:00 0.045 8 1.10 0.091 Computed Peaks 0.229 50.00 0.980 Weston Heights Technical Information Report West Basin – Developed Condition (Detained Basin) Flow Frequency Analysis Time Series File:west-dev.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.373 4 2/09/01 2:00 0.683 1 100.00 0.990 0.220 8 12/03/01 17:00 0.451 2 25.00 0.960 0.367 5 9/10/03 15:00 0.429 3 10.00 0.900 0.429 3 8/26/04 1:00 0.373 4 5.00 0.800 0.353 7 10/28/04 18:00 0.367 5 3.00 0.667 0.366 6 10/22/05 17:00 0.366 6 2.00 0.500 0.451 2 11/21/06 9:00 0.353 7 1.30 0.231 0.683 1 1/09/08 7:00 0.220 8 1.10 0.091 Computed Peaks 0.606 50.00 0.980 Weston Heights Technical Information Report West Basin – Developed Condition (Bypass Basin) Flow Frequency Analysis Time Series File:west-byp.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.065 3 2/09/01 2:00 0.132 1 100.00 0.990 0.027 8 12/03/01 17:00 0.079 2 25.00 0.960 0.040 7 2/28/03 16:00 0.065 3 10.00 0.900 0.058 4 8/26/04 1:00 0.058 4 5.00 0.800 0.045 6 10/28/04 18:00 0.047 5 3.00 0.667 0.047 5 10/22/05 17:00 0.045 6 2.00 0.500 0.079 2 11/21/06 9:00 0.040 7 1.30 0.231 0.132 1 1/09/08 7:00 0.027 8 1.10 0.091 Computed Peaks 0.115 50.00 0.980 Weston Heights Technical Information Report West Basin – Vault Design Calculations Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 128.00 ft Facility Width: 24.00 ft Facility Area: 3072. sq. ft Effective Storage Depth: 7.50 ft Stage 0 Elevation: 505.80 ft Storage Volume: 23040. cu. ft Riser Head: 7.50 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 0.75 0.042 2 3.75 1.13 0.066 4.0 3 6.20 0.88 0.024 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 505.80 0. 0.000 0.000 0.00 0.01 505.81 31. 0.001 0.001 0.00 0.02 505.82 61. 0.001 0.002 0.00 0.03 505.83 92. 0.002 0.003 0.00 0.04 505.84 123. 0.003 0.003 0.00 0.05 505.85 154. 0.004 0.004 0.00 0.06 505.86 184. 0.004 0.004 0.00 0.21 506.01 645. 0.015 0.007 0.00 0.36 506.16 1106. 0.025 0.009 0.00 0.50 506.30 1536. 0.035 0.011 0.00 0.65 506.45 1997. 0.046 0.012 0.00 0.80 506.60 2458. 0.056 0.014 0.00 0.94 506.74 2888. 0.066 0.015 0.00 1.09 506.89 3349. 0.077 0.016 0.00 1.24 507.04 3809. 0.087 0.017 0.00 1.39 507.19 4270. 0.098 0.018 0.00 1.53 507.33 4700. 0.108 0.019 0.00 1.68 507.48 5161. 0.118 0.020 0.00 1.83 507.63 5622. 0.129 0.021 0.00 1.97 507.77 6052. 0.139 0.021 0.00 2.12 507.92 6513. 0.150 0.022 0.00 2.27 508.07 6973. 0.160 0.023 0.00 2.42 508.22 7434. 0.171 0.024 0.00 2.56 508.36 7864. 0.181 0.024 0.00 2.71 508.51 8325. 0.191 0.025 0.00 2.86 508.66 8786. 0.202 0.026 0.00 3.00 508.80 9216. 0.212 0.026 0.00 3.15 508.95 9677. 0.222 0.027 0.00 3.30 509.10 10138. 0.233 0.028 0.00 3.44 509.24 10568. 0.243 0.028 0.00 3.59 509.39 11028. 0.253 0.029 0.00 3.74 509.54 11489. 0.264 0.030 0.00 3.75 509.55 11520. 0.264 0.030 0.00 3.76 509.56 11551. 0.265 0.030 0.00 3.77 509.57 11581. 0.266 0.031 0.00 3.79 509.59 11643. 0.267 0.032 0.00 3.80 509.60 11674. 0.268 0.034 0.00 3.81 509.61 11704. 0.269 0.036 0.00 3.82 509.62 11735. 0.269 0.039 0.00 3.83 509.63 11766. 0.270 0.040 0.00 3.84 509.64 11796. 0.271 0.040 0.00 Weston Heights Technical Information Report 3.99 509.79 12257. 0.281 0.047 0.00 4.14 509.94 12718. 0.292 0.052 0.00 4.28 510.08 13148. 0.302 0.057 0.00 4.43 510.23 13609. 0.312 0.060 0.00 4.58 510.38 14070. 0.323 0.064 0.00 4.73 510.53 14531. 0.334 0.067 0.00 4.87 510.67 14961. 0.343 0.070 0.00 5.02 510.82 15421. 0.354 0.073 0.00 5.17 510.97 15882. 0.365 0.076 0.00 5.31 511.11 16312. 0.374 0.078 0.00 5.46 511.26 16773. 0.385 0.081 0.00 5.61 511.41 17234. 0.396 0.083 0.00 5.76 511.56 17695. 0.406 0.085 0.00 5.90 511.70 18125. 0.416 0.087 0.00 6.05 511.85 18586. 0.427 0.090 0.00 6.20 512.00 19046. 0.437 0.092 0.00 6.21 512.01 19077. 0.438 0.092 0.00 6.22 512.02 19108. 0.439 0.093 0.00 6.23 512.03 19139. 0.439 0.093 0.00 6.24 512.04 19169. 0.440 0.095 0.00 6.25 512.05 19200. 0.441 0.097 0.00 6.26 512.06 19231. 0.441 0.098 0.00 6.27 512.07 19261. 0.442 0.098 0.00 6.42 512.22 19722. 0.453 0.104 0.00 6.57 512.37 20183. 0.463 0.109 0.00 6.71 512.51 20613. 0.473 0.114 0.00 6.86 512.66 21074. 0.484 0.117 0.00 7.01 512.81 21535. 0.494 0.121 0.00 7.16 512.96 21996. 0.505 0.124 0.00 7.30 513.10 22426. 0.515 0.128 0.00 7.45 513.25 22886. 0.525 0.131 0.00 7.50 513.30 23040. 0.529 0.132 0.00 7.60 513.40 23347. 0.536 0.442 0.00 7.70 513.50 23654. 0.543 1.010 0.00 7.80 513.60 23962. 0.550 1.740 0.00 7.90 513.70 24269. 0.557 2.530 0.00 8.00 513.80 24576. 0.564 2.820 0.00 8.10 513.90 24883. 0.571 3.070 0.00 8.20 514.00 25190. 0.578 3.310 0.00 8.30 514.10 25498. 0.585 3.530 0.00 8.40 514.20 25805. 0.592 3.740 0.00 8.50 514.30 26112. 0.599 3.930 0.00 Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 0.68 0.50 7.61 513.41 23378. 0.537 2 0.45 0.12 7.02 512.82 21558. 0.495 3 0.43 0.02 2.70 508.50 8309. 0.191 4 0.37 0.12 6.95 512.75 21347. 0.490 5 0.37 0.05 3.97 509.77 12209. 0.280 6 0.37 0.02 1.55 507.35 4759. 0.109 7 0.35 0.02 1.86 507.66 5708. 0.131 8 0.22 0.02 1.26 507.06 3863. 0.089 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.50 0.13 ******** 0.25 0.57 2 0.12 0.08 ******** ******* 0.17 3 0.02 0.06 ******** ******* 0.08 4 0.12 0.07 ******** ******* 0.16 5 0.05 0.05 ******** ******* 0.06 6 0.02 0.04 ******** ******* 0.05 7 0.02 0.05 ******** ******* 0.06 8 0.02 0.03 ******** ******* 0.03 ---------------------------------- Route Time Series through Facility Inflow Time Series File:west-dev.tsf Outflow Time Series File:West-RDOut POC Time Series File:West-DSOut Weston Heights Technical Information Report Inflow/Outflow Analysis Peak Inflow Discharge: 0.683 CFS at 7:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.499 CFS at 9:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.61 Ft Peak Reservoir Elev: 513.41 Ft Peak Reservoir Storage: 23378. Cu-Ft : 0.537 Ac-Ft Add Time Series:west-byp.tsf Peak Summed Discharge: 0.573 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:West-DSOut.tsf Duration Comparison Anaylsis Base File: west-pre.tsf New File: west-dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.047 | 0.91E-02 0.88E-02 -3.2 | 0.91E-02 0.047 0.046 -1.9 0.057 | 0.60E-02 0.61E-02 3.3 | 0.60E-02 0.057 0.059 2.0 0.068 | 0.39E-02 0.42E-02 7.9 | 0.39E-02 0.068 0.069 1.8 0.079 | 0.26E-02 0.26E-02 -1.3 | 0.26E-02 0.079 0.078 -0.2 0.089 | 0.16E-02 0.17E-02 4.0 | 0.16E-02 0.089 0.092 3.0 0.100 | 0.11E-02 0.13E-02 14.3 | 0.11E-02 0.100 0.106 6.3 0.110 | 0.88E-03 0.98E-03 11.1 | 0.88E-03 0.110 0.114 3.0 0.121 | 0.68E-03 0.65E-03 -4.8 | 0.68E-03 0.121 0.121 -0.3 0.132 | 0.47E-03 0.42E-03 -10.3 | 0.47E-03 0.132 0.130 -1.0 0.142 | 0.31E-03 0.24E-03 -21.1 | 0.31E-03 0.142 0.139 -2.6 0.153 | 0.15E-03 0.82E-04 -44.4 | 0.15E-03 0.153 0.147 -3.7 0.164 | 0.98E-04 0.16E-04 -83.3 | 0.98E-04 0.164 0.152 -7.1 0.174 | 0.49E-04 0.00E+00 -100.0 | 0.49E-04 0.174 0.154 -11.6 0.185 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.185 0.165 -10.8 Maximum positive excursion = 0.007 cfs ( 7.0%) occurring at 0.099 cfs on the Base Data:west-pre.tsf and at 0.106 cfs on the New Data:west-dsout.tsf Maximum negative excursion = 0.029 cfs (-15.6%) occurring at 0.182 cfs on the Base Data:west-pre.tsf and at 0.154 cfs on the New Data:west-dsout.tsf Weston Heights Technical Information Report East Basin – Existing Condition Flow Frequency Analysis Time Series File:east-pre.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.135 2 2/09/01 18:00 0.160 1 100.00 0.990 0.022 7 1/05/02 16:00 0.135 2 25.00 0.960 0.086 4 2/28/03 16:00 0.109 3 10.00 0.900 0.016 8 3/03/04 3:00 0.086 4 5.00 0.800 0.079 5 1/05/05 10:00 0.079 5 3.00 0.667 0.063 6 1/18/06 21:00 0.063 6 2.00 0.500 0.109 3 11/24/06 5:00 0.022 7 1.30 0.231 0.160 1 1/09/08 7:00 0.016 8 1.10 0.091 Computed Peaks 0.151 50.00 0.980 Weston Heights Technical Information Report East Basin – Developed Condition (Detained Basin) Flow Frequency Analysis Time Series File:east-dev.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.326 4 2/09/01 2:00 0.612 1 100.00 0.990 0.179 8 12/03/01 17:00 0.394 2 25.00 0.960 0.289 6 9/10/03 15:00 0.355 3 10.00 0.900 0.355 3 8/26/04 1:00 0.326 4 5.00 0.800 0.289 7 10/28/04 18:00 0.299 5 3.00 0.667 0.299 5 10/22/05 17:00 0.289 6 2.00 0.500 0.394 2 11/21/06 9:00 0.289 7 1.30 0.231 0.612 1 1/09/08 7:00 0.179 8 1.10 0.091 Computed Peaks 0.540 50.00 0.980 Weston Heights Technical Information Report East Basin – Developed Condition (Bypass Basin) Flow Frequency Analysis Time Series File:east-byp.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.013 7 2/09/01 2:00 0.022 1 100.00 0.990 0.009 8 12/03/01 17:00 0.017 2 25.00 0.960 0.016 4 9/10/03 15:00 0.017 3 10.00 0.900 0.017 2 8/26/04 1:00 0.016 4 5.00 0.800 0.014 6 10/28/04 18:00 0.015 5 3.00 0.667 0.015 5 10/22/05 17:00 0.014 6 2.00 0.500 0.017 3 10/26/06 3:00 0.013 7 1.30 0.231 0.022 1 1/09/08 7:00 0.009 8 1.10 0.091 Computed Peaks 0.020 50.00 0.980 Weston Heights Technical Information Report East Basin – Pond Design Calculations Type of Facility: Detention Pond Side Slope: 3.50 H:1V Pond Bottom Length: 66.00 ft Pond Bottom Width: 60.00 ft Pond Bottom Area: 3960. sq. ft Top Area at 1 ft. FB: 8921. sq. ft 0.205 acres Effective Storage Depth: 3.50 ft Stage 0 Elevation: 518.50 ft Storage Volume: 19963. cu. ft 0.458 ac-ft Riser Head: 3.50 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 0.88 0.039 2 2.10 1.25 0.050 4.0 3 2.60 0.63 0.010 4.0 Top Notch Weir: Rectangular Length: 1.50 in Weir Height: 3.20 ft Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) (sq. ft) 0.00 518.50 0. 0.000 0.000 0.00 3960. 0.01 518.51 40. 0.001 0.002 0.00 3969. 0.02 518.52 79. 0.002 0.003 0.00 3978. 0.03 518.53 119. 0.003 0.003 0.00 3987. 0.04 518.54 159. 0.004 0.004 0.00 3995. 0.05 518.55 199. 0.005 0.005 0.00 4004. 0.06 518.56 239. 0.005 0.005 0.00 4013. 0.07 518.57 279. 0.006 0.006 0.00 4022. 0.17 518.67 686. 0.016 0.009 0.00 4111. 0.27 518.77 1102. 0.025 0.011 0.00 4202. 0.37 518.87 1526. 0.035 0.013 0.00 4293. 0.47 518.97 1960. 0.045 0.014 0.00 4385. 0.57 519.07 2404. 0.055 0.016 0.00 4479. 0.67 519.17 2856. 0.066 0.017 0.00 4573. 0.77 519.27 3318. 0.076 0.018 0.00 4668. 0.87 519.37 3790. 0.087 0.019 0.00 4764. 0.97 519.47 4271. 0.098 0.020 0.00 4862. 1.07 519.57 4762. 0.109 0.022 0.00 4960. 1.17 519.67 5263. 0.121 0.022 0.00 5059. 1.27 519.77 5774. 0.133 0.023 0.00 5159. 1.37 519.87 6295. 0.145 0.024 0.00 5260. 1.47 519.97 6826. 0.157 0.025 0.00 5362. 1.57 520.07 7367. 0.169 0.026 0.00 5466. 1.67 520.17 7919. 0.182 0.027 0.00 5570. 1.77 520.27 8481. 0.195 0.028 0.00 5675. 1.87 520.37 9054. 0.208 0.028 0.00 5781. 1.97 520.47 9638. 0.221 0.029 0.00 5888. 2.07 520.57 10232. 0.235 0.030 0.00 5996. 2.10 520.60 10412. 0.239 0.030 0.00 6028. 2.11 520.61 10472. 0.240 0.030 0.00 6039. 2.13 520.63 10593. 0.243 0.032 0.00 6061. 2.14 520.64 10654. 0.245 0.033 0.00 6072. 2.15 520.65 10715. 0.246 0.036 0.00 6083. 2.17 520.67 10837. 0.249 0.039 0.00 6105. 2.18 520.68 10898. 0.250 0.042 0.00 6116. 2.19 520.69 10959. 0.252 0.044 0.00 6127. 2.20 520.70 11020. 0.253 0.045 0.00 6138. 2.22 520.72 11143. 0.256 0.045 0.00 6160. 2.32 520.82 11765. 0.270 0.051 0.00 6270. 2.42 520.92 12397. 0.285 0.056 0.00 6381. Weston Heights Technical Information Report 2.52 521.02 13041. 0.299 0.060 0.00 6494. 2.60 521.10 13564. 0.311 0.063 0.00 6584. 2.61 521.11 13630. 0.313 0.064 0.00 6596. 2.62 521.12 13696. 0.314 0.065 0.00 6607. 2.63 521.13 13762. 0.316 0.067 0.00 6619. 2.64 521.14 13829. 0.317 0.067 0.00 6630. 2.65 521.15 13895. 0.319 0.068 0.00 6641. 2.75 521.25 14565. 0.334 0.073 0.00 6756. 2.85 521.35 15246. 0.350 0.077 0.00 6872. 2.95 521.45 15939. 0.366 0.081 0.00 6988. 3.05 521.55 16644. 0.382 0.085 0.00 7106. 3.15 521.65 17360. 0.399 0.088 0.00 7225. 3.20 521.70 17723. 0.407 0.090 0.00 7284. 3.24 521.74 18015. 0.414 0.094 0.00 7332. 3.28 521.78 18310. 0.420 0.100 0.00 7380. 3.31 521.81 18532. 0.425 0.106 0.00 7416. 3.35 521.85 18829. 0.432 0.113 0.00 7465. 3.39 521.89 19129. 0.439 0.119 0.00 7513. 3.42 521.92 19355. 0.444 0.125 0.00 7550. 3.46 521.96 19658. 0.451 0.131 0.00 7598. 3.50 522.00 19963. 0.458 0.140 0.00 7647. 3.60 522.10 20733. 0.476 0.451 0.00 7770. 3.70 522.20 21517. 0.494 1.020 0.00 7894. 3.80 522.30 22312. 0.512 1.750 0.00 8019. 3.90 522.40 23120. 0.531 2.540 0.00 8145. 4.00 522.50 23941. 0.550 2.830 0.00 8272. 4.10 522.60 24775. 0.569 3.090 0.00 8400. 4.20 522.70 25621. 0.588 3.320 0.00 8529. 4.30 522.80 26481. 0.608 3.540 0.00 8659. 4.40 522.90 27353. 0.628 3.750 0.00 8789. 4.50 523.00 28239. 0.648 3.950 0.00 8921. 4.60 523.10 29137. 0.669 4.130 0.00 9054. 4.70 523.20 30049. 0.690 4.310 0.00 9188. 4.80 523.30 30975. 0.711 4.480 0.00 9323. 4.90 523.40 31914. 0.733 4.650 0.00 9458. 5.00 523.50 32867. 0.755 4.810 0.00 9595. 5.10 523.60 33833. 0.777 4.960 0.00 9733. 5.20 523.70 34813. 0.799 5.110 0.00 9871. 5.30 523.80 35807. 0.822 5.260 0.00 10011. 5.40 523.90 36815. 0.845 5.400 0.00 10152. 5.50 524.00 37838. 0.869 5.530 0.00 10293. Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 0.61 0.44 3.60 522.10 20717. 0.476 2 0.39 0.10 3.27 521.77 18270. 0.419 3 0.33 0.10 3.26 521.76 18154. 0.417 4 0.19 0.06 2.46 520.96 12658. 0.291 5 0.21 0.06 2.46 520.96 12630. 0.290 6 0.30 0.03 1.95 520.45 9505. 0.218 7 0.35 0.02 1.33 519.83 6066. 0.139 8 0.18 0.02 0.92 519.42 4031. 0.093 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.44 0.02 ******** 0.16 0.46 2 0.10 0.02 ******** ******* 0.10 3 0.10 0.01 ******** ******* 0.10 4 0.06 0.01 ******** ******* 0.06 5 0.06 0.01 ******** ******* 0.06 6 0.03 0.02 ******** ******* 0.03 7 0.02 0.02 ******** ******* 0.04 8 0.02 0.01 ******** ******* 0.02 Weston Heights Technical Information Report ---------------------------------- Route Time Series through Facility Inflow Time Series File:east-dev.tsf Outflow Time Series File:East-RDOut POC Time Series File:East-DSOut Inflow/Outflow Analysis Peak Inflow Discharge: 0.612 CFS at 7:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.444 CFS at 9:00 on Jan 9 in Year 8 Peak Reservoir Stage: 3.60 Ft Peak Reservoir Elev: 522.10 Ft Peak Reservoir Storage: 20717. Cu-Ft : 0.476 Ac-Ft Add Time Series:east-byp.tsf Peak Summed Discharge: 0.457 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:East-DSOut.tsf Flow Duration from Time Series File:east-dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.001 29975 48.883 48.883 51.117 0.511E+00 0.004 5372 8.761 57.644 42.356 0.424E+00 0.007 4870 7.942 65.585 34.415 0.344E+00 0.010 5302 8.646 74.232 25.768 0.258E+00 0.013 4563 7.441 81.673 18.327 0.183E+00 0.016 3748 6.112 87.785 12.215 0.122E+00 0.018 2627 4.284 92.069 7.931 0.793E-01 0.021 1607 2.621 94.690 5.310 0.531E-01 0.024 1152 1.879 96.569 3.431 0.343E-01 0.027 782 1.275 97.844 2.156 0.216E-01 0.030 616 1.005 98.849 1.151 0.115E-01 0.032 244 0.398 99.247 0.753 0.753E-02 0.035 61 0.099 99.346 0.654 0.654E-02 0.038 28 0.046 99.392 0.608 0.608E-02 0.041 13 0.021 99.413 0.587 0.587E-02 0.044 14 0.023 99.436 0.564 0.564E-02 0.047 45 0.073 99.509 0.491 0.491E-02 0.049 46 0.075 99.584 0.416 0.416E-02 0.052 41 0.067 99.651 0.349 0.349E-02 0.055 48 0.078 99.729 0.271 0.271E-02 0.058 26 0.042 99.772 0.228 0.228E-02 0.061 18 0.029 99.801 0.199 0.199E-02 0.064 12 0.020 99.821 0.179 0.179E-02 0.066 3 0.005 99.826 0.174 0.174E-02 0.069 7 0.011 99.837 0.163 0.163E-02 0.072 7 0.011 99.848 0.152 0.152E-02 0.075 7 0.011 99.860 0.140 0.140E-02 0.078 10 0.016 99.876 0.124 0.124E-02 0.080 7 0.011 99.887 0.113 0.113E-02 0.083 9 0.015 99.902 0.098 0.978E-03 0.086 15 0.024 99.927 0.073 0.734E-03 0.089 15 0.024 99.951 0.049 0.489E-03 0.092 10 0.016 99.967 0.033 0.326E-03 0.095 7 0.011 99.979 0.021 0.212E-03 0.097 5 0.008 99.987 0.013 0.130E-03 0.100 6 0.010 99.997 0.003 0.326E-04 Weston Heights Technical Information Report Duration Comparison Anaylsis Base File: east-pre.tsf New File: east-dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.030 | 0.11E-01 0.11E-01 -5.7 | 0.11E-01 0.030 0.030 -0.8 0.038 | 0.75E-02 0.61E-02 -18.7 | 0.75E-02 0.038 0.033 -14.2 0.046 | 0.53E-02 0.50E-02 -5.3 | 0.53E-02 0.046 0.045 -1.4 0.054 | 0.33E-02 0.30E-02 -10.0 | 0.33E-02 0.054 0.053 -2.3 0.062 | 0.21E-02 0.19E-02 -9.2 | 0.21E-02 0.062 0.059 -4.7 0.070 | 0.15E-02 0.16E-02 2.1 | 0.15E-02 0.070 0.071 1.8 0.078 | 0.11E-02 0.12E-02 10.3 | 0.11E-02 0.078 0.081 3.5 0.086 | 0.78E-03 0.73E-03 -6.3 | 0.78E-03 0.086 0.086 -0.6 0.094 | 0.57E-03 0.21E-03 -62.9 | 0.57E-03 0.094 0.088 -6.9 0.102 | 0.33E-03 0.00E+00 -100.0 | 0.33E-03 0.102 0.092 -10.6 0.111 | 0.20E-03 0.00E+00 -100.0 | 0.20E-03 0.111 0.095 -13.8 0.119 | 0.15E-03 0.00E+00 -100.0 | 0.15E-03 0.119 0.097 -18.0 0.127 | 0.98E-04 0.00E+00 -100.0 | 0.98E-04 0.127 0.098 -22.6 0.135 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.135 0.101 -24.9 Maximum positive excursion = 0.004 cfs ( 4.7%) occurring at 0.075 cfs on the Base Data:east-pre.tsf and at 0.078 cfs on the New Data:east-dsout.tsf Maximum negative excursion = 0.033 cfs (-24.9%) occurring at 0.135 cfs on the Base Data:east-pre.tsf and at 0.101 cfs on the New Data:east-dsout.tsf Weston Heights Technical Information Report Equivalent East Pond Detention Storage Made by: Date: 6/6/2016 Checked by: Date: Backchecked by: Date: Estimated Pond Length =66 ft Estimated Pond Width =60 ft Estimated Side Slope =3.5 :1 Measured Calculated Calculated Calculated Calculated Calculated Contour Contour Incremental Cumulative Contour Contour Incremental Cumulative Elevation Area Volume Volume Elevation Area Volume Volume (ft) (cu ft) (cu ft) (cu ft) (ft) (sq ft) (cu ft) (cu ft)Comparison 518.5 3,956 0 0 518.5 3,960 0 0 0 519.0 4,433 2,097 2,097 519.0 4,413 2,093 2,093 (4) 519.5 4,930 2,341 4,438 519.5 4,891 2,326 4,419 (19) 520.0 5,445 2,594 7,032 520.0 5,393 2,571 6,990 (41) 520.5 5,977 2,856 9,887 520.5 5,920 2,828 9,819 (69) 521.0 6,527 3,126 13,013 521.0 6,471 3,098 12,917 (97) 521.5 7,095 3,406 16,419 521.5 7,047 3,380 16,296 (123) 522.0 7,679 3,694 20,112 522.0 7,647 3,674 19,970 (143) 522.5 8,282 3,990 24,103 522.5 8,272 3,980 23,950 (153) 523.0 8,901 4,296 28,398 523.0 8,921 4,298 28,248 (150) Measured from CAD Drawing Project Name: Project No: Sheet No: Weston Heights Theoretical Pond Volume CalculationMeasured Pond Volume Calculation KJM KJM KJM Weston Heights Technical Information Report Predeveloped Olympus Villa Pond ‘A’ Basin Flow Frequency Analysis Time Series File:predev.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 0.222 2 2/09/01 18:00 0.303 1 100.00 0.990 0.075 7 1/05/02 16:00 0.222 2 25.00 0.960 0.178 3 2/28/03 3:00 0.178 3 10.00 0.900 0.025 8 8/26/04 2:00 0.176 4 5.00 0.800 0.107 6 1/05/05 8:00 0.157 5 3.00 0.667 0.176 4 1/18/06 20:00 0.107 6 2.00 0.500 0.157 5 11/24/06 4:00 0.075 7 1.30 0.231 0.303 1 1/09/08 9:00 0.025 8 1.10 0.091 Computed Peaks 0.276 50.00 0.980 *The original design information for Olympus Villa Pond ‘A’ may be found in the provided “Olympus Villa LUA 10-090” report included in Appendix 6C. The original predeveloped areas for Olympus Villa were: - 2.78 ac Till Forest - 0.10 ac Existing Wetland (modeled as impervious) The Weston North project added the following values to the predeveloped conditions: - 0.40 ac Till Forest Weston Heights Technical Information Report Developed Olympus Village Basin Flow Frequency Analysis Time Series File:dev.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 0.633 6 2/09/01 2:00 1.29 1 100.00 0.990 0.510 8 1/05/02 16:00 0.792 2 25.00 0.960 0.763 3 2/27/03 7:00 0.763 3 10.00 0.900 0.545 7 8/26/04 2:00 0.671 4 5.00 0.800 0.658 5 10/28/04 16:00 0.658 5 3.00 0.667 0.671 4 1/18/06 16:00 0.633 6 2.00 0.500 0.792 2 10/26/06 0:00 0.545 7 1.30 0.231 1.29 1 1/09/08 6:00 0.510 8 1.10 0.091 Computed Peaks 1.12 50.00 0.980 *The original design information for Olympus Villa Pond ‘A’ may be found in the provided “Olympus Villa LUA 10-090” report included in Appendix 6C. The original developed areas for Olympus Villa were: - 1.35 ac Till Grass - 1.77 ac Impervious The Weston North project added the following values to the predeveloped conditions: - 0.09 ac Till Grass - 0.31 ac Impervious Weston Heights Technical Information Report Olympus Village Pond ‘A’ Revised Riser Design & Equivalent Area/Volume Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.35 H:1V Pond Bottom Length: 96.36 ft Pond Bottom Width: 60.51 ft Pond Bottom Area: 5831. sq. ft Top Area at 1 ft. FB: 10980. sq. ft 0.252 acres Effective Storage Depth: 4.93 ft Stage 0 Elevation: 0.00 ft Storage Volume: 38588. cu. ft 0.886 ac-ft Riser Head: 4.93 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 1.04 0.065 2 3.27 1.63 0.092 4.0 3 3.90 1.04 0.030 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 0.00 0. 0.000 0.000 0.00 5831. 0.01 0.01 58. 0.001 0.003 0.00 5838. 0.02 0.02 117. 0.003 0.004 0.00 5846. 0.03 0.03 175. 0.004 0.005 0.00 5853. 0.04 0.04 234. 0.005 0.006 0.00 5860. 0.05 0.05 293. 0.007 0.007 0.00 5868. 0.06 0.06 351. 0.008 0.007 0.00 5875. 0.08 0.08 469. 0.011 0.008 0.00 5890. 0.09 0.09 528. 0.012 0.009 0.00 5897. 0.10 0.10 587. 0.013 0.009 0.00 5905. 0.20 0.20 1181. 0.027 0.013 0.00 5979. 0.30 0.30 1783. 0.041 0.016 0.00 6054. 0.40 0.40 2392. 0.055 0.018 0.00 6129. 0.50 0.50 3009. 0.069 0.021 0.00 6205. 0.60 0.60 3633. 0.083 0.023 0.00 6281. 0.70 0.70 4265. 0.098 0.024 0.00 6358. 0.80 0.80 4904. 0.113 0.026 0.00 6435. 0.90 0.90 5552. 0.127 0.028 0.00 6512. 1.00 1.00 6207. 0.142 0.029 0.00 6590. 1.10 1.10 6870. 0.158 0.031 0.00 6669. 1.20 1.20 7541. 0.173 0.032 0.00 6747. 1.30 1.30 8219. 0.189 0.033 0.00 6827. 1.40 1.40 8906. 0.204 0.035 0.00 6906. 1.50 1.50 9601. 0.220 0.036 0.00 6986. 1.60 1.60 10303. 0.237 0.037 0.00 7067. 1.70 1.70 11014. 0.253 0.038 0.00 7148. 1.80 1.80 11733. 0.269 0.039 0.00 7230. 1.90 1.90 12460. 0.286 0.040 0.00 7311. 2.00 2.00 13195. 0.303 0.041 0.00 7394. 2.10 2.10 13939. 0.320 0.042 0.00 7477. 2.20 2.20 14691. 0.337 0.043 0.00 7560. 2.30 2.30 15451. 0.355 0.044 0.00 7643. Weston Heights Technical Information Report 2.40 2.40 16219. 0.372 0.045 0.00 7728. 2.50 2.50 16996. 0.390 0.046 0.00 7812. 2.60 2.60 17782. 0.408 0.047 0.00 7897. 2.70 2.70 18576. 0.426 0.048 0.00 7983. 2.80 2.80 19378. 0.445 0.049 0.00 8068. 2.90 2.90 20189. 0.463 0.050 0.00 8155. 3.00 3.00 21009. 0.482 0.051 0.00 8242. 3.10 3.10 21838. 0.501 0.052 0.00 8329. 3.20 3.20 22675. 0.521 0.052 0.00 8416. 3.27 3.27 23266. 0.534 0.053 0.00 8478. 3.29 3.29 23436. 0.538 0.054 0.00 8496. 3.30 3.30 23521. 0.540 0.055 0.00 8504. 3.32 3.32 23691. 0.544 0.058 0.00 8522. 3.34 3.34 23862. 0.548 0.062 0.00 8540. 3.35 3.35 23947. 0.550 0.067 0.00 8549. 3.37 3.37 24118. 0.554 0.073 0.00 8566. 3.39 3.39 24290. 0.558 0.079 0.00 8584. 3.41 3.41 24462. 0.562 0.080 0.00 8602. 3.42 3.42 24548. 0.564 0.082 0.00 8611. 3.52 3.52 25413. 0.583 0.091 0.00 8700. 3.62 3.62 26288. 0.603 0.098 0.00 8789. 3.72 3.72 27171. 0.624 0.105 0.00 8879. 3.82 3.82 28064. 0.644 0.110 0.00 8970. 3.90 3.90 28784. 0.661 0.115 0.00 9042. 3.91 3.91 28875. 0.663 0.115 0.00 9051. 3.92 3.92 28965. 0.665 0.117 0.00 9060. 3.93 3.93 29056. 0.667 0.118 0.00 9070. 3.94 3.94 29147. 0.669 0.120 0.00 9079. 3.95 3.95 29237. 0.671 0.123 0.00 9088. 3.96 3.96 29328. 0.673 0.125 0.00 9097. 3.98 3.98 29510. 0.677 0.127 0.00 9115. 3.99 3.99 29602. 0.680 0.128 0.00 9124. 4.09 4.09 30519. 0.701 0.137 0.00 9216. 4.19 4.19 31445. 0.722 0.144 0.00 9308. 4.29 4.29 32380. 0.743 0.151 0.00 9400. 4.39 4.39 33325. 0.765 0.157 0.00 9493. 4.49 4.49 34279. 0.787 0.163 0.00 9587. 4.59 4.59 35242. 0.809 0.169 0.00 9680. 4.69 4.69 36215. 0.831 0.175 0.00 9775. 4.79 4.79 37197. 0.854 0.180 0.00 9869. 4.89 4.89 38189. 0.877 0.185 0.00 9964. 4.93 4.93 38588. 0.886 0.187 0.00 10003. 5.03 5.03 39593. 0.909 0.500 0.00 10098. 5.13 5.13 40608. 0.932 1.070 0.00 10194. 5.23 5.23 41632. 0.956 1.800 0.00 10291. 5.33 5.33 42666. 0.979 2.600 0.00 10388. 5.43 5.43 43710. 1.003 2.880 0.00 10486. 5.53 5.53 44763. 1.028 3.140 0.00 10584. 5.63 5.63 45827. 1.052 3.380 0.00 10682. 5.73 5.73 46900. 1.077 3.600 0.00 10781. 5.83 5.83 47983. 1.102 3.810 0.00 10880. 5.93 5.93 49076. 1.127 4.010 0.00 10980. 6.03 6.03 50179. 1.152 4.200 0.00 11080. 6.13 6.13 51292. 1.177 4.380 0.00 11181. 6.23 6.23 52415. 1.203 4.550 0.00 11282. 6.33 6.33 53548. 1.229 4.720 0.00 11383. 6.43 6.43 54691. 1.256 4.880 0.00 11485. 6.53 6.53 55845. 1.282 5.040 0.00 11587. 6.63 6.63 57009. 1.309 5.190 0.00 11690. 6.73 6.73 58183. 1.336 5.330 0.00 11793. 6.83 6.83 59368. 1.363 5.470 0.00 11897. 6.93 6.93 60563. 1.390 5.610 0.00 12001. Weston Heights Technical Information Report Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft) 1 1.29 0.30 0.83 5.09 5.09 40178. 0.922 2 0.79 ******* 0.05 3.01 3.01 21125. 0.485 3 0.76 ******* 0.15 4.31 4.31 32548. 0.747 4 0.67 ******* 0.11 3.82 3.82 28033. 0.644 5 0.66 ******* 0.04 1.60 1.60 10319. 0.237 6 0.63 ******* 0.19 4.93 4.93 38544. 0.885 7 0.54 ******* 0.04 2.14 2.14 14214. 0.326 8 0.51 ******* 0.05 2.86 2.86 19900. 0.457 ---------------------------------- Route Time Series through Facility Inflow Time Series File:dev.tsf Outflow Time Series File:OV_rdout.tsf Inflow/Outflow Analysis Peak Inflow Discharge: 1.29 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.828 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 5.09 Ft Peak Reservoir Elev: 5.09 Ft Peak Reservoir Storage: 40179. Cu-Ft : 0.922 Ac-Ft Duration Comparison Anaylsis Base File: predev.tsf New File: ov_rdout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.053 | 0.76E-02 0.66E-02 -12.3 | 0.76E-02 0.053 0.052 -1.2 0.066 | 0.56E-02 0.53E-02 -4.1 | 0.56E-02 0.066 0.061 -7.6 0.078 | 0.43E-02 0.49E-02 14.8 | 0.43E-02 0.078 0.085 8.9 0.091 | 0.32E-02 0.38E-02 17.6 | 0.32E-02 0.091 0.096 5.5 0.103 | 0.25E-02 0.28E-02 12.6 | 0.25E-02 0.103 0.107 3.7 0.116 | 0.18E-02 0.16E-02 -10.9 | 0.18E-02 0.116 0.113 -2.5 0.128 | 0.12E-02 0.14E-02 18.9 | 0.12E-02 0.128 0.137 6.9 0.141 | 0.91E-03 0.11E-02 19.6 | 0.91E-03 0.141 0.147 4.7 0.153 | 0.59E-03 0.67E-03 13.9 | 0.59E-03 0.153 0.157 2.3 0.166 | 0.36E-03 0.34E-03 -4.5 | 0.36E-03 0.166 0.165 -0.4 0.178 | 0.18E-03 0.16E-03 -9.1 | 0.18E-03 0.178 0.177 -0.4 0.191 | 0.13E-03 0.33E-04 -75.0 | 0.13E-03 0.191 0.181 -5.1 0.203 | 0.82E-04 0.00E+00 -100.0 | 0.82E-04 0.203 0.185 -9.0 0.216 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.216 0.199 -7.8 Maximum positive excursion = 0.007 cfs ( 9.5%) occurring at 0.073 cfs on the Base Data:predev.tsf and at 0.080 cfs on the New Data:ov_rdout.tsf Maximum negative excursion = 0.006 cfs (-10.4%) occurring at 0.061 cfs on the Base Data:predev.tsf and at 0.054 cfs on the New Data:ov_rdout.tsf Weston Heights Technical Information Report Equivalent Olympus Villa Pond ‘A’ Dimensions/Side Slope Weston Heights Technical Information Report APPENDIX 4B WATER QUALITY DESIGN CALCULATIONS Weston Heights Technical Information Report KCSWDM – SCALE FACTOR Date: 6/20/2016 Date: Date: Wetpool Description: Step 1: Identify the required wetpool volume factor (f) f =3 Fixed value per KCSWDM Section 6.4.1.1 (P. 6‐70) Step 2: Determine rainfall (R ) for the mean annual storm R =0.47 in Per KCSWDM Figure 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V r ) for the developed site A i =46,174 ft2 Area of impervious surface A tg =36,155 ft2 Area of till soil covered with grass A tf =0 ft2 Area of till soil covered with forest A o =0 ft2 Area of outwash soil covered with grass or forest R =0.47inRainfall from mean annual storm (from Step 2) V r = 1,982 ft2 [KCSWDM Eq. 6‐13] Step 4: Calculate required wetpool volume (V b ) VB = 5,945 ft3 [KCSWDM Equation 6‐14] Step 5: Calculate minimum required wetpool depth (DREQ) Z1 =0.00 H:1V Side Slope #1 Z2 =0.00 H:1V Side Slope #2 Z3 =0.00 H:1V End Slope #3 Z4 =0.00 H:1V End Slope #4 LPOND =64 ft Pond length at top of wetpool WPOND =24 ft Pond width at top of wetpool DREQ =3.87ft Minimum required pond depth Made by: Checked by: Backchecked by: Project: Project No: Weston Heights 349‐004 KJM Weston Heights ‐ West Vault Wetpool Sizing Calculation (Per KCSWDM Section 6.4.1.1) ܸ ൌ݂ ܸ ܸ ൌ 0.9ܣ 0.25ܣ௧ 0.10ܣ௧ 0.01ܣ ൈ ܴ Weston Heights Technical Information Report East Basin Stormfilter Treatment Calculations: Flow Frequency Analysis Time Series File:east_dev_15min.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.134 7 2/08/01 19:00 0.473 1 100.00 0.990 0.116 8 5/06/02 7:15 0.320 2 25.00 0.960 0.240 4 9/10/03 13:45 0.291 3 10.00 0.900 0.320 2 8/25/04 23:30 0.240 4 5.00 0.800 0.172 6 9/10/05 16:45 0.208 5 3.00 0.667 0.291 3 10/22/05 16:15 0.172 6 2.00 0.500 0.208 5 11/21/06 8:00 0.134 7 1.30 0.231 0.473 1 1/09/08 7:30 0.116 8 1.10 0.091 Computed Peaks 0.422 50.00 0.980 Per Section 6.5.5.1 of the 2009 KCSWDM: o The water quality design flow, preceding detention, shall be 35% of the developed two-year peak flow rate, as determined using the KCRTS model with 15-minute time steps calibrated to site conditions. 35% of the 2-YR, 15-MIN peak flow for the East Basin Treatment receiving runoff areas: o 35% x 0.172-CFS (2-YR, 15-MIN peak from KCRTS above) = 0.060-CFS Weston Heights Technical Information Report East Basin Stormfilter Cartridge Calculations: Weston Heights Technical Information Report Olympus Villa – Original Design Wetpool Volme *This is the original design required volume for water quality in the Olympus Villa Pond ‘A’. The as-built facility provides 15,479-CF of volume, for a difference of 5,598-CF in additional wetpool storage capacity. Weston Heights Technical Information Report Olympus Villa – Proposed Design Wetpool Volume *This is the required wetpool volume resulting from the addition of the Weston North basin area to Olympus Villa Pond ‘A’ (depicted as North Basin in the basin figures). This volume is below the as-built facility’s 15,479-CF of useable wetpool storage. The additional areas from Weston North leaves a remainder of 4,055-CF in wetpool storage capacity. Weston Heights Technical Information Report APPENDIX 4C WETLAND HYDROPERIOD CALCULATIONS Weston Heights Technical Information Report WWHM2012 – Wetland Fluctuation Report WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Wetland Hydroperiod_160428 Site Name: Weston Heights Site Address: Nile Ave City : Renton Report Date: 4/28/2016 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.17 Version : 2015/02/16 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Wetland Basin Bypass: No GroundWater: No Pervious Land Use Acres C, Forest, Mod 2.39 C, Lawn, Flat 1.64 Pervious Total 4.03 Impervious Land Use Acres ROADS FLAT 0.12 Impervious Total 0.12 Basin Total 4.15 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Weston Heights Technical Information Report Bypass: No GroundWater: No Pervious Land Use Acres C, Forest, Mod 3.12 C, Lawn, Flat .97 Pervious Total 4.09 Impervious Land Use Acres ROADS FLAT 0.2 Impervious Total 0.2 Basin Total 4.29 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Wetlands Fluctuation for POC 1 Average Annual Volume (acft) Month Predevel Mitigated Percent Pass/Fail Jan 83.5601 85.4451 102.3 Pass Feb 63.2200 65.3305 103.3 Pass Mar 54.1575 56.2056 103.8 Pass Apr 33.8289 35.4218 104.7 Pass May 18.5240 19.5652 105.6 Pass Jun 14.2424 14.8053 104.0 Pass Jul 9.8981 10.5291 106.4 Pass Aug 9.1697 9.4648 103.2 Pass Sep 9.0665 9.1604 101.0 Pass Oct 17.9055 16.5603 92.5 Pass Nov 53.2741 50.4882 94.8 Pass Dec 75.5175 75.7115 100.3 Pass Day Predevel Mitigated Percent Pass/Fail Jan1 2.7430 2.7996 102.1 Pass 2 2.7092 2.7360 101.0 Pass 3 2.5126 2.5642 102.1 Pass 4 2.8627 2.9198 102.0 Pass 5 2.9059 2.9554 101.7 Pass 6 3.0584 3.1118 101.7 Pass 7 2.8224 2.8662 101.6 Pass 8 2.8327 2.8714 101.4 Pass 9 2.4328 2.4934 102.5 Pass 10 2.2725 2.3262 102.4 Pass 11 2.4503 2.5090 102.4 Pass 12 2.5436 2.6150 102.8 Pass 13 3.0111 3.0849 102.4 Pass 14 3.0505 3.1042 101.8 Pass Weston Heights Technical Information Report 15 2.7660 2.8236 102.1 Pass 16 2.7902 2.8485 102.1 Pass 17 2.7323 2.8003 102.5 Pass 18 2.9999 3.0679 102.3 Pass 19 2.8991 2.9676 102.4 Pass 20 2.6959 2.7573 102.3 Pass 21 2.4794 2.5448 102.6 Pass 22 2.6825 2.7551 102.7 Pass 23 3.0014 3.0673 102.2 Pass 24 2.7711 2.8221 101.8 Pass 25 2.4305 2.4932 102.6 Pass 26 2.4197 2.4913 103.0 Pass 27 2.3875 2.4641 103.2 Pass 28 2.5203 2.6023 103.3 Pass 29 2.7496 2.8209 102.6 Pass 30 2.6812 2.7648 103.1 Pass 31 2.6590 2.7262 102.5 Pass Feb1 2.4262 2.4988 103.0 Pass 2 2.1887 2.2553 103.0 Pass 3 2.1662 2.2403 103.4 Pass 4 1.8991 1.9733 103.9 Pass 5 2.0356 2.1262 104.5 Pass 6 2.1972 2.2769 103.6 Pass 7 2.6078 2.6987 103.5 Pass 8 2.6145 2.6957 103.1 Pass 9 2.2087 2.2876 103.6 Pass 10 1.9356 2.0120 103.9 Pass 11 2.1449 2.2283 103.9 Pass 12 2.2049 2.2720 103.0 Pass 13 2.0175 2.0856 103.4 Pass 14 2.1635 2.2449 103.8 Pass 15 2.3941 2.4611 102.8 Pass 16 2.3948 2.4674 103.0 Pass 17 2.3224 2.3998 103.3 Pass 18 2.7174 2.7909 102.7 Pass 19 2.4868 2.5510 102.6 Pass 20 2.2243 2.3027 103.5 Pass 21 2.0803 2.1537 103.5 Pass 22 2.0157 2.0922 103.8 Pass 23 2.1781 2.2516 103.4 Pass 24 2.1322 2.2020 103.3 Pass 25 1.9896 2.0550 103.3 Pass 26 2.1143 2.1824 103.2 Pass 27 2.1150 2.1921 103.6 Pass 28 2.2285 2.3121 103.8 Pass 29 1.9059 1.9778 103.8 Pass Mar1 1.8695 1.9373 103.6 Pass 2 2.1162 2.1852 103.3 Pass 3 2.1276 2.1975 103.3 Pass 4 2.2343 2.3093 103.4 Pass 5 1.8870 1.9545 103.6 Pass 6 1.7340 1.8067 104.2 Pass 7 1.6571 1.7386 104.9 Pass 8 1.9223 1.9958 103.8 Pass 9 1.9731 2.0379 103.3 Pass 10 1.9524 2.0255 103.7 Pass 11 2.1620 2.2379 103.5 Pass Weston Heights Technical Information Report 12 1.9730 2.0331 103.0 Pass 13 1.8341 1.8971 103.4 Pass 14 1.8731 1.9439 103.8 Pass 15 1.7426 1.8084 103.8 Pass 16 1.7716 1.8356 103.6 Pass 17 1.7369 1.8094 104.2 Pass 18 1.6771 1.7380 103.6 Pass 19 1.5238 1.5859 104.1 Pass 20 1.3688 1.4277 104.3 Pass 21 1.5437 1.6248 105.3 Pass 22 1.7103 1.7829 104.2 Pass 23 1.6897 1.7536 103.8 Pass 24 1.6292 1.6837 103.3 Pass 25 1.5146 1.5666 103.4 Pass 26 1.4484 1.5040 103.8 Pass 27 1.3629 1.4221 104.3 Pass 28 1.4321 1.4931 104.3 Pass 29 1.4413 1.4978 103.9 Pass 30 1.3416 1.3946 104.0 Pass 31 1.2912 1.3478 104.4 Pass Apr1 1.2031 1.2601 104.7 Pass 2 1.2292 1.2826 104.3 Pass 3 1.4703 1.5395 104.7 Pass 4 1.5932 1.6572 104.0 Pass 5 1.4277 1.4872 104.2 Pass 6 1.2210 1.2746 104.4 Pass 7 1.2380 1.2993 105.0 Pass 8 1.3309 1.3909 104.5 Pass 9 1.2034 1.2559 104.4 Pass 10 1.1577 1.2110 104.6 Pass 11 1.1392 1.1899 104.5 Pass 12 1.1922 1.2505 104.9 Pass 13 1.1368 1.1903 104.7 Pass 14 1.0513 1.1053 105.1 Pass 15 1.2047 1.2642 104.9 Pass 16 1.2644 1.3112 103.7 Pass 17 0.9998 1.0446 104.5 Pass 18 1.1756 1.2387 105.4 Pass 19 1.2570 1.2949 103.0 Pass 20 0.9942 1.0365 104.3 Pass 21 0.9451 1.0008 105.9 Pass 22 1.1374 1.1943 105.0 Pass 23 0.9987 1.0472 104.9 Pass 24 0.8788 0.9229 105.0 Pass 25 0.7714 0.8168 105.9 Pass 26 0.8072 0.8612 106.7 Pass 27 0.7815 0.8253 105.6 Pass 28 0.8216 0.8731 106.3 Pass 29 0.9064 0.9490 104.7 Pass 30 0.8834 0.9228 104.5 Pass May1 0.8146 0.8496 104.3 Pass 2 0.7234 0.7600 105.1 Pass 3 0.7039 0.7488 106.4 Pass 4 0.7335 0.7749 105.7 Pass 5 0.7237 0.7665 105.9 Pass 6 0.6674 0.7062 105.8 Pass 7 0.6067 0.6435 106.1 Pass Weston Heights Technical Information Report 8 0.5894 0.6257 106.2 Pass 9 0.5948 0.6307 106.0 Pass 10 0.6170 0.6626 107.4 Pass 11 0.5564 0.5955 107.0 Pass 12 0.5951 0.6329 106.4 Pass 13 0.6041 0.6433 106.5 Pass 14 0.5836 0.6170 105.7 Pass 15 0.5778 0.6056 104.8 Pass 16 0.5337 0.5674 106.3 Pass 17 0.5369 0.5741 106.9 Pass 18 0.5724 0.6132 107.1 Pass 19 0.5710 0.6015 105.3 Pass 20 0.5182 0.5499 106.1 Pass 21 0.5125 0.5431 106.0 Pass 22 0.5033 0.5415 107.6 Pass 23 0.4946 0.5305 107.3 Pass 24 0.4706 0.5002 106.3 Pass 25 0.4739 0.5153 108.7 Pass 26 0.4951 0.5175 104.5 Pass 27 0.5079 0.5275 103.9 Pass 28 0.5618 0.5786 103.0 Pass 29 0.5996 0.6155 102.7 Pass 30 0.5979 0.6034 100.9 Pass 31 0.5806 0.5854 100.8 Pass Jun1 0.6004 0.6055 100.9 Pass 2 0.5982 0.6175 103.2 Pass 3 0.5865 0.6056 103.2 Pass 4 0.5109 0.5287 103.5 Pass 5 0.5241 0.5516 105.2 Pass 6 0.6303 0.6345 100.7 Pass 7 0.5774 0.5865 101.6 Pass 8 0.5766 0.5913 102.6 Pass 9 0.5866 0.6012 102.5 Pass 10 0.5274 0.5470 103.7 Pass 11 0.5057 0.5235 103.5 Pass 12 0.4584 0.4724 103.0 Pass 13 0.4170 0.4388 105.2 Pass 14 0.4063 0.4347 107.0 Pass 15 0.4152 0.4432 106.7 Pass 16 0.4373 0.4683 107.1 Pass 17 0.4199 0.4422 105.3 Pass 18 0.3956 0.4221 106.7 Pass 19 0.3964 0.4263 107.5 Pass 20 0.4374 0.4543 103.8 Pass 21 0.4318 0.4411 102.1 Pass 22 0.4067 0.4267 104.9 Pass 23 0.4853 0.5103 105.1 Pass 24 0.4480 0.4510 100.7 Pass 25 0.3991 0.4133 103.6 Pass 26 0.3748 0.3968 105.9 Pass 27 0.3709 0.3978 107.3 Pass 28 0.3681 0.3934 106.9 Pass 29 0.3693 0.3946 106.8 Pass 30 0.3923 0.4125 105.1 Pass Jul1 0.3715 0.3919 105.5 Pass 2 0.3610 0.3819 105.8 Pass 3 0.3479 0.3681 105.8 Pass Weston Heights Technical Information Report 4 0.3485 0.3731 107.1 Pass 5 0.3339 0.3550 106.3 Pass 6 0.3323 0.3581 107.8 Pass 7 0.3402 0.3653 107.4 Pass 8 0.3416 0.3684 107.8 Pass 9 0.3339 0.3563 106.7 Pass 10 0.3199 0.3399 106.3 Pass 11 0.3344 0.3605 107.8 Pass 12 0.3449 0.3613 104.7 Pass 13 0.3392 0.3563 105.0 Pass 14 0.3227 0.3355 104.0 Pass 15 0.3399 0.3678 108.2 Pass 16 0.3213 0.3378 105.2 Pass 17 0.3107 0.3272 105.3 Pass 18 0.3072 0.3278 106.7 Pass 19 0.3010 0.3213 106.7 Pass 20 0.2948 0.3141 106.5 Pass 21 0.2980 0.3189 107.0 Pass 22 0.2921 0.3116 106.7 Pass 23 0.2869 0.3054 106.4 Pass 24 0.2856 0.3048 106.7 Pass 25 0.2988 0.3252 108.8 Pass 26 0.2873 0.3051 106.2 Pass 27 0.2835 0.3014 106.3 Pass 28 0.2769 0.2934 106.0 Pass 29 0.2751 0.2925 106.3 Pass 30 0.2745 0.2909 106.0 Pass 31 0.2818 0.3005 106.6 Pass Aug1 0.2813 0.3024 107.5 Pass 2 0.3049 0.3185 104.5 Pass 3 0.2855 0.2991 104.8 Pass 4 0.2758 0.2878 104.4 Pass 5 0.2902 0.3087 106.4 Pass 6 0.2885 0.3086 107.0 Pass 7 0.2744 0.2850 103.9 Pass 8 0.2818 0.3005 106.6 Pass 9 0.2690 0.2811 104.5 Pass 10 0.2651 0.2811 106.0 Pass 11 0.2607 0.2773 106.4 Pass 12 0.2557 0.2714 106.1 Pass 13 0.2935 0.3102 105.7 Pass 14 0.3247 0.3305 101.8 Pass 15 0.2920 0.2953 101.2 Pass 16 0.2925 0.2988 102.2 Pass 17 0.3120 0.3206 102.7 Pass 18 0.2945 0.3062 104.0 Pass 19 0.2755 0.2839 103.1 Pass 20 0.2755 0.2931 106.4 Pass 21 0.2855 0.3060 107.2 Pass 22 0.3410 0.3527 103.4 Pass 23 0.3444 0.3402 98.8 Pass 24 0.3414 0.3305 96.8 Pass 25 0.3505 0.3404 97.1 Pass 26 0.3272 0.3276 100.1 Pass 27 0.2986 0.3018 101.1 Pass 28 0.3044 0.3102 101.9 Pass 29 0.3133 0.3040 97.0 Pass Weston Heights Technical Information Report 30 0.2885 0.2907 100.7 Pass 31 0.2829 0.2920 103.2 Pass Sep1 0.2818 0.2928 103.9 Pass 2 0.2649 0.2760 104.2 Pass 3 0.2810 0.2948 104.9 Pass 4 0.2587 0.2683 103.7 Pass 5 0.2713 0.2866 105.7 Pass 6 0.2465 0.2535 102.8 Pass 7 0.2661 0.2814 105.8 Pass 8 0.2659 0.2723 102.4 Pass 9 0.2721 0.2907 106.9 Pass 10 0.2597 0.2718 104.7 Pass 11 0.2652 0.2650 99.9 Pass 12 0.2525 0.2612 103.4 Pass 13 0.2644 0.2858 108.1 Pass 14 0.2478 0.2625 106.0 Pass 15 0.2569 0.2724 106.0 Pass 16 0.3463 0.3665 105.8 Pass 17 0.3285 0.3195 97.3 Pass 18 0.3278 0.3260 99.5 Pass 19 0.3146 0.3129 99.5 Pass 20 0.3152 0.3066 97.3 Pass 21 0.3942 0.3844 97.5 Pass 22 0.4552 0.4186 92.0 Pass 23 0.3714 0.3580 96.4 Pass 24 0.3180 0.3182 100.0 Pass 25 0.3202 0.3175 99.2 Pass 26 0.3047 0.3079 101.1 Pass 27 0.3497 0.3356 96.0 Pass 28 0.3116 0.3019 96.9 Pass 29 0.3716 0.3596 96.8 Pass 30 0.3468 0.3239 93.4 Pass Oct1 0.3370 0.3196 94.8 Pass 2 0.3294 0.3268 99.2 Pass 3 0.3590 0.3592 100.1 Pass 4 0.3794 0.3560 93.8 Pass 5 0.6622 0.6462 97.6 Pass 6 0.5517 0.5325 96.5 Pass 7 0.5764 0.5612 97.4 Pass 8 0.6355 0.5789 91.1 Pass 9 0.6238 0.5688 91.2 Pass 10 0.4975 0.4426 89.0 Pass 11 0.3969 0.3778 95.2 Pass 12 0.3829 0.3732 97.5 Pass 13 0.3533 0.3530 99.9 Pass 14 0.3660 0.3517 96.1 Pass 15 0.3655 0.3549 97.1 Pass 16 0.4480 0.4314 96.3 Pass 17 0.5083 0.4632 91.1 Pass 18 0.5993 0.5414 90.4 Pass 19 0.9120 0.8373 91.8 Pass 20 0.9762 0.8892 91.1 Pass 21 0.7848 0.7081 90.2 Pass 22 0.6761 0.6041 89.3 Pass 23 0.6093 0.5494 90.2 Pass 24 0.5887 0.5399 91.7 Pass 25 0.6908 0.6137 88.8 Pass Weston Heights Technical Information Report 26 0.7488 0.6723 89.8 Pass 27 0.7848 0.6819 86.9 Pass 28 0.8381 0.7455 89.0 Pass 29 0.8031 0.7360 91.6 Pass 30 0.7731 0.7210 93.3 Pass 31 0.7833 0.7183 91.7 Pass Nov1 0.8828 0.8152 92.3 Pass 2 1.1326 1.0302 91.0 Pass 3 1.3244 1.1552 87.2 Pass 4 1.1448 0.9786 85.5 Pass 5 1.3206 1.1962 90.6 Pass 6 1.3471 1.2203 90.6 Pass 7 1.1443 1.0365 90.6 Pass 8 1.2744 1.1724 92.0 Pass 9 1.4212 1.3107 92.2 Pass 10 1.6837 1.5733 93.4 Pass 11 1.8512 1.7018 91.9 Pass 12 1.7836 1.6399 91.9 Pass 13 1.8537 1.7018 91.8 Pass 14 1.5832 1.4738 93.1 Pass 15 1.5666 1.4737 94.1 Pass 16 1.6178 1.5200 94.0 Pass 17 1.6998 1.5989 94.1 Pass 18 2.0576 1.9994 97.2 Pass 19 2.3915 2.3007 96.2 Pass 20 2.2344 2.1405 95.8 Pass 21 1.9792 1.9091 96.5 Pass 22 2.0826 2.0479 98.3 Pass 23 2.9019 2.8301 97.5 Pass 24 2.9612 2.9111 98.3 Pass 25 2.6232 2.5607 97.6 Pass 26 2.3597 2.2893 97.0 Pass 27 1.9725 1.9268 97.7 Pass 28 2.0196 1.9959 98.8 Pass 29 2.2769 2.2599 99.3 Pass 30 2.1939 2.1554 98.2 Pass Dec1 2.3079 2.2620 98.0 Pass 2 2.8916 2.8564 98.8 Pass 3 2.6311 2.6009 98.9 Pass 4 2.3432 2.3375 99.8 Pass 5 2.3360 2.3093 98.9 Pass 6 2.0890 2.0749 99.3 Pass 7 2.0435 2.0358 99.6 Pass 8 2.1148 2.1203 100.3 Pass 9 2.3573 2.3600 100.1 Pass 10 2.4178 2.4195 100.1 Pass 11 2.5444 2.5379 99.7 Pass 12 2.5694 2.5602 99.6 Pass 13 2.6401 2.6304 99.6 Pass 14 3.0557 3.0670 100.4 Pass 15 2.7431 2.7507 100.3 Pass 16 2.4663 2.4639 99.9 Pass 17 2.2397 2.2491 100.4 Pass 18 2.0809 2.1023 101.0 Pass 19 2.4036 2.4372 101.4 Pass 20 2.4839 2.4928 100.4 Pass 21 2.3052 2.3162 100.5 Pass Weston Heights Technical Information Report 22 2.3251 2.3472 100.9 Pass 23 2.2466 2.2660 100.9 Pass 24 2.1462 2.1858 101.8 Pass 25 2.5632 2.6077 101.7 Pass 26 2.9059 2.9379 101.1 Pass 27 2.3743 2.3980 101.0 Pass 28 2.3438 2.4014 102.5 Pass 29 2.9308 2.9714 101.4 Pass 30 2.4225 2.4575 101.4 Pass 31 2.3459 2.3966 102.2 Pass ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. 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Weston Heights Technical Information Report WWHM2012 – Fluctuation Analysis Weston Heights Technical Information Report SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Weston Heights Technical Information Report Conveyance System Analysis and Design The project is proposing a conveyance system for each project basin. The conveyance system along Nile Ave is not a conventional layout. An existing storm drain line is located at the proposed flow line of the frontage improvements. A shallow concrete inlet will be installed at the proposed flow line, which will tie into a CB Type 1 located behind the proposed sidewalk. The KCSWDM requires that the conveyance flows tributary to each catch basin be calculated with KCRTS using 15-minute timesteps. The KCSWDM also requires that the 25-year peak design flows be contained within the conveyance system with no surcharge. The 100-year peak design flows must also be analyzed, and it must be demonstrated that any surcharge during the 100-year peak design event must not cause or aggravate a flooding problem. Systems downstream of the proposed detention systems have not been included as the release rates are a reduction of the flows entering the facilities. Conveyance calculations for this project are provided in Appendix 5A. For simplicity of the calculation, and in order to provide a conservative design, the calculations only analyze the 100-year storm event, and show that there is no surcharge during that event. The 100-yr flows from detention facilities were routed through the downstream systems – Stormshed 3G analyzed a fixed flow rate for these systems. Weston Heights Technical Information Report APPENDIX 5A CONVEYANCE CALCULATIONS BASIN #8UNDISTURBEDWETLANDAREABASIN#14BASIN #12BASIN #11BASIN #1(BYPASSAREA)VAULTBASINBASIN #5BASIN#5ABASIN#IN1BASIN #13POND BASINDateProject No.DrawnDesignSheet:JDAJDA3/16/16349-004-15DEVELOPEDCONVEYANCEWESTON HEIGHTS NORTHN#BASINAREAIMERVIOUSAREALAWNAREATOTALWESTON HEIGHTS BASIN AREAS Weston Heights Technical Information Report Weston Heights Conveyance – Stormshed 3G Report Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:36:57 PM ROUTEHYD [] THRU [Layout-01] USING [100 year] AND [TYPE1A.RAC] NOTZERO RELATIVE SCS/SBUH Gravity Analysis using 24 hr duration storm Reach ID Area (ac) Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Depth ratio Size nVel (ft/s) fVel (ft/s) Infil Vol (cf) CBasin / Hyd P-08 0.72 0.5615 7.1149 0.0789 0.1896 0.1896 12 in Diam 5.4196 9.059 0.00 BASIN-08 P-07 0.72 0.5615 7.8191 0.0718 0.1814 0.1814 12 in Diam 5.7752 9.9556 0.00 P-IN1 0.15 0.1346 8.121 0.0166 0.0897 0.0897 12 in Diam 3.8622 10.34 0.00 BASIN- IN1 P-05A 0.05 0.0516 7.3126 0.0071 0.06 0.06 12 in Diam 2.6823 9.3107 0.00 BASIN- 05A P-05 0.80 0.7993 7.052 0.1133 0.2278 0.2278 12 in Diam 5.9377 8.9789 0.00 BASIN-05 P-VLT- IN 1.52 1.3608 15.7574 0.0864 0.1985 0.1985 12 in Diam 12.2986 20.063 0.00 BASIN-3 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft)Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 504.9935 CB4 VAULT-IN 511.1361 ------ 0.0689 0.2370 511.4420 513.4900 CB7 CB4 513.5107 ------ 0.5770 ------ 514.0877 517.8600 CB8 CB7 516.1246 ------ ------ ------ 516.1246 518.7100 CB5 CB4 513.1183 ------ 0.0273 0.0624 513.2081 516.4500 INLET1 CB5 514.9033 --na-- --na-- --na-- 514.9033 515.7200 CB5A CB5 513.3186 ------ ------ ------ 513.3186 515.4600 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment P-VLT-IN 0.6461 0.6461 1.36 0.4935 0.4935 0.1985 SuperCrit flow, Inlet end controls P-07 0.4107 0.4107 0.56 0.9520 0.3113 0.1814 SuperCrit flow, Inlet end controls P-08 0.4146 0.4146 0.56 0.9877 0.3113 0.1896 SuperCrit flow, Inlet end controls P-05 0.5083 0.5083 0.80 0.9520 0.3738 0.2278 SuperCrit flow, Inlet end controls P-IN1 0.1833 0.1833 0.13 0.5981 0.1496 0.0897 SuperCrit flow, Inlet end controls P-05A 0.1086 0.1086 0.05 0.5981 0.0919 0.0600 SuperCrit flow, Inlet end controls Licensed to: SDA Engineers Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:35:34 PM Layout Report: Layout-01 Event Precip (in) other 2.10 2 yr 24 hr 2.50 5 year 3.50 10 year 4.00 25 year 4.25 100 year 4.50 Reach Records Record Id: P-05 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB4 UpNode CB5 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 76.00 ft Slope 2.79% Up Invert 512.61 ft Dn Invert 510.49 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-05A Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB5 UpNode CB5A Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 20.00 ft Slope 3.00% Up Invert 513.21 ft Dn Invert 512.61 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Weston Heights Technical Information Report Record Id: P-07 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB4 UpNode CB7 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 76.00 ft Slope 3.43% Up Invert 513.10 ft Dn Invert 510.49 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-08 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB7 UpNode CB8 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 92.00 ft Slope 2.84% Up Invert 515.71 ft Dn Invert 513.10 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-IN1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB5 UpNode INLET1 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 57.00 ft Slope 3.70% Up Invert 514.72 ft Dn Invert 512.61 ft Conduit Constraints Weston Heights Technical Information Report Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-VLT-IN Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode VAULT-IN UpNode CB4 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 43.00 ft Slope 13.93% Up Invert 510.49 ft Dn Invert 504.50 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Node Records Record Id: CB4 Descrip: TYPE 1 Increment 0.10 ft Start El. 510.49 ft Max El. 513.49 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: CB5 Descrip: TYPE 1 Increment 0.10 ft Start El. 512.61 ft Max El. 516.45 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Weston Heights Technical Information Report Record Id: CB5A Descrip: CONCRETE INLET Increment 0.10 ft Start El. 513.21 ft Max El. 515.46 ft Void Ratio 100.00 Condition Proposed Structure Type CONCRETE INLET Channelization No Special Shape Catch 0.00 ft Bottom Area 3.67 sf MH/CB Type Node Record Id: CB7 Descrip: TYPE 1 Increment 0.10 ft Start El. 513.10 ft Max El. 517.86 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: CB8 Descrip: TYPE 1 Increment 0.10 ft Start El. 515.71 ft Max El. 518.71 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: INLET1 Descrip: PIPE INLET Increment 0.10 ft Start El. 514.72 ft Max El. 515.72 ft Void Ratio 100.00 Dummy Type Node Record Id: VAULT-IN Descrip: COMBINED DETENTION/WETPOOL VAULT Increment 0.10 ft Start El. 501.00 ft Max El. 513.80 Weston Heights Technical Information Report ft Void Ratio 100.00 Dummy Type Node Contributing Drainage Areas Record Id: BASIN-05 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.02 ac DCIA 0.58 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.02 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.58 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-05A Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.00 ac DCIA 0.05 ac Pervious CN 0.00 DC CN 98.00 Pervious TC 0.00 min DC TC 5.00 min DCI - CN Calc Weston Heights Technical Information Report Description SubArea Sub cn Impervious 0.05 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-08 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.63 ac DCIA 0.09 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.63 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.09 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-3 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.63 ac DCIA 0.09 ac Weston Heights Technical Information Report Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.63 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.09 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-IN1 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.07 ac DCIA 0.08 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.07 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.08 ac 98.00 DC Composited CN (AMC 2) 98.00 Weston Heights Technical Information Report DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Licensed to: SDA Engineers Weston Heights Technical Information Report Weston Heights Conveyance – Stormshed 3G Report Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:43:33 PM ROUTEHYD [] THRU [Layout-02] USING [100 year] AND [] NOTZERO RELATIVE Fixed Flow Gravity Analysis using fixed flowrates Reach ID Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Size nVel (ft/s) fVel (ft/s) CFlow P-02 0.83 2.9853 0.278 0.3606 12 in Diam 3.2537 3.8011 0.83 P-VAULTOUT 0.50 0.1522 3.2846 1.00 12 in Diam 0.6366 0.1938 0.50 P-03 0.50 2.9853 0.1675 0.2764 12 in Diam 2.8279 3.8011 0.00 P-01 1.402 2.9853 0.4696 0.4822 12 in Diam 3.7395 3.8011 0.072 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft)Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 505.6012 CB1 DITCH OUTLET 506.3703 ------ 0.0670 0.0635 506.5008 510.6400 CB2 CB1 506.6998 ------ ------ ------ 506.6998 511.0100 CB3 CB1 506.6510 0.0063 0.0054 ------ 506.6502 516.0300 VAULT-IN CB3 506.8086 --na-- --na-- --na-- 506.8086 513.8000 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment P-01 0.7203 0.7203 1.40 0.5012 0.5012 0.4822 SuperCrit flow, Inlet end controls P-02 0.9898 0.9898 0.83 0.8508 0.3813 0.3606 Outlet Control M1 Backwater P-03 0.8510 0.8510 0.50 0.8508 0.2932 0.2764 Outlet Control M1 Backwater P-VAULTOUT 1.0087 1.0087 0.50 1.0000 0.2932 >D Outlet Control Licensed to: SDA Engineers Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:45:27 PM Layout Report: Layout-02 Event Precip (in) other 2.10 2 yr 24 hr 2.50 5 year 3.50 10 year 4.00 25 year 4.25 100 year 4.50 Reach Records Record Id: P-01 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode DITCH OUTLET UpNode CB1 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 109.00 ft Slope 0.50% Up Invert 505.65 ft Dn Invert 505.10 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-02 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB1 UpNode CB2 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 12.00 ft Slope 0.50% Up Invert 505.71 ft Dn Invert 505.65 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Weston Heights Technical Information Report Record Id: P-03 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB1 UpNode CB3 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 30.00 ft Slope 0.50% Up Invert 505.80 ft Dn Invert 505.65 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-VAULTOUT Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB3 UpNode VAULT-IN Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 8.00 ft Slope 0.00% Up Invert 505.80 ft Dn Invert 505.7999 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Node Records Record Id: CB1 Descrip: TYPE 1 Increment 0.10 ft Start El. 505.65 ft Max El. 510.64 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Weston Heights Technical Information Report Record Id: CB2 Descrip: TYPE 1 (Solid lid, flows from OV Pond A) Increment 0.10 ft Start El. 505.71 ft Max El. 511.01 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: CB3 Descrip: CONTROL STRUCTURE Increment 0.10 ft Start El. 505.80 ft Max El. 516.03 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 2-54 Channelization No Special Shape Catch 0.00 ft Bottom Area 15.904 sf MH/CB Type Node Record Id: DITCH OUTLET Descrip: DOWNSTREAM OUTLET INTO DITCH Increment 0.10 ft Start El. 505.10 ft Max El. 506.10 ft Void Ratio 100.00 Dummy Type Node Record Id: VAULT-IN Descrip: COMBINED DETENTION/WETPOOL VAULT Increment 0.10 ft Start El. 501.00 ft Max El. 513.80 ft Void Ratio 100.00 Dummy Type Node Licensed to: SDA Engineers Weston Heights Technical Information Report Weston Heights Conveyance – Stormshed 3G Report Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:55:14 PM ROUTEHYD [] THRU [Layout-03] USING [100 year] AND [TYPE1A.RAC] NOTZERO RELATIVE SCS/SBUH Gravity Analysis using 24 hr duration storm Reach ID Area (ac) Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Depth ratio Size nVel (ft/s) fVel (ft/s) Infil Vol (cf) CBasin / Hyd P-14 0.10 0.0888 3.5575 0.025 0.1091 0.1091 12 in Diam 1.9107 4.5295 0.00 BASIN-14 P-13 0.33 0.2944 2.9853 0.0986 0.212 0.212 12 in Diam 2.4225 3.8011 0.00 BASIN-13 P-12 0.56 0.50 4.9236 0.1015 0.2148 0.2148 12 in Diam 4.0366 6.2689 0.00 BASIN-12 P-11 0.81 0.7262 5.031 0.1443 0.2562 0.2562 12 in Diam 4.5694 6.4057 0.00 BASIN-11 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 518.8556 No approach losses at node CB12 because inverts and/or crowns are offset. CB11 POND-IN 519.9376 ------ 0.0770 ------ 520.0146 524.2600 CB12 CB11 523.1757 ------ 0.0003 ------ 523.1761 525.2400 CB13 CB12 523.4308 ------ 0.0002 ------ 523.4310 526.1700 CB14 CB13 524.7795 ------ ------ ------ 524.7795 527.9900 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment P-11 0.4876 0.4876 0.73 0.3556 0.3556 0.2562 SuperCrit flow, Inlet end controls P-12 0.3957 0.3957 0.50 0.2932 0.2932 0.2148 SuperCrit flow, Inlet end controls P-13 0.3008 0.3008 0.29 0.3961 0.2234 0.2120 SuperCrit flow, Inlet end controls P-14 0.1595 0.1595 0.09 0.3010 0.1213 0.1091 SuperCrit flow, Inlet end controls Licensed to: SDA Engineers Weston Heights Technical Information Report Appended on: Thursday, June 16, 2016 3:55:56 PM Layout Report: Layout-03 Event Precip (in) other 2.10 2 yr 24 hr 2.50 5 year 3.50 10 year 4.00 25 year 4.25 100 year 4.50 Reach Records Record Id: P-11 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode POND-IN UpNode CB11 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 67.00 ft Slope 1.42% Up Invert 519.45 ft Dn Invert 518.50 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-12 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB11 UpNode CB12 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 76.00 ft Slope 1.36% Up Invert 522.78 ft Dn Invert 521.75 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Weston Heights Technical Information Report Record Id: P-13 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB12 UpNode CB13 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 70.00 ft Slope 0.50% Up Invert 523.13 ft Dn Invert 522.78 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: P-14 Section Shape: Circular Uniform Flow Method: Manning's Coefficient:0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode CB13 UpNode CB14 Material unspecified Size 12 in Diam Ent Losses Square Edge w/Headwall Length 210.00 ft Slope 0.71% Up Invert 524.62 ft Dn Invert 523.13 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Node Records Record Id: CB11 Descrip: STORMFILTER Increment 0.10 ft Start El. 519.45 ft Max El. 524.26 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Weston Heights Technical Information Report Record Id: CB12 Descrip: TYPE 1 Increment 0.10 ft Start El. 522.78 ft Max El. 525.24 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: CB13 Descrip: TYPE 1 Increment 0.10 ft Start El. 523.13 ft Max El. 526.17 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: CB14 Descrip: TYPE 1 Increment 0.10 ft Start El. 524.62 ft Max El. 527.99 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: POND-IN Descrip: INLET TO POND Increment 0.10 ft Start El. 518.50 ft Max El. 519.50 ft Void Ratio 100.00 Dummy Type Node Weston Heights Technical Information Report Contributing Drainage Areas Record Id: BASIN-11 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.11 ac DCIA 0.14 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.11 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.14 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-12 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.11 ac DCIA 0.12 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.11 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Weston Heights Technical Information Report Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.12 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-13 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.11 ac DCIA 0.12 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.11 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.12 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-14 Weston Heights Technical Information Report Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.05 ac DCIA 0.05 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Lawn 0.05 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Tc min = 5 min 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min DCI - CN Calc Description SubArea Sub cn Impervious 0.05 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Licensed to: SDA Engineers Weston Heights Technical Information Report APPENDIX 5B ISOPLUVIAL MAP – 100-YR, 24-HR PRECIPITATION Weston Heights Technical Information Report SECTION 6 SPECIAL REPORTS AND STUDIES Weston Heights Technical Information Report Special Reports and Studies A geotechnical report was prepared by Geo Group Northwest for the project on February 12th, 2015. A copy of this report is included in Appendix 6A. A copy of the Olympus Villa LUA 10-090 TIR has been attached as Appendix 6B. The Olympus Villa Pond ‘A’ was utilized as part of this project. A copy of the Olympus Villa original design and As-Built plans has been attached as Appendix 6C. The Olympus Villa Pond ‘A’ was utilized as part of this project. Weston Heights Technical Information Report APPENDIX 6A GEOTECHNICAL REPORT Weston Heights Technical Information Report APPENDIX 6B OLYMPUS VILLA LUA 10-090 Weston Heights Technical Information Report APPENDIX 6C OLYMPUS VILLA AS-BUILT PLANS Weston Heights Technical Information Report SECTION 7 OTHER PERMITS Weston Heights Technical Information Report Other Permits This project will require the following permits: Grading Permit - City of Renton Right-of-Way Use Permit - City of Renton Construction Stormwater Permit - WA Dept. of Ecology Weston Heights Technical Information Report SECTION 8 CSWPPP ANALYSIS AND DESIGN Weston Heights Technical Information Report ESC Plan Analysis and Design This section, along with the Temporary Erosion and Sediment Control (TESC) Plan contained in the engineering drawings, is intended to serve as the construction Stormwater Pollution Prevention Plan (SWPPP) for the project. The SWPPP is outlined in conformance with the 2005 edition of the Washington State Department of Ecology’s Stormwater Management Manual for Western Washington (DOE Manual). 1.0 – INTRODUCTION An introductory overview of the project has been provided in the Project Overview section of this report. 2.0 – SITE DESCRIPTION A general site description has been provided in the Project Overview section of this report. Additional detailed information is provided through the rest of this report. 3.0 – CONSTRUCTION STORMWATER BMPs 3.1 – 12 BMP ELEMENTS Element #1 – Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated, both in the field and on the plans. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. The BMPs relevant to marking the clearing limits are identified in Appendix 8B. Alternate BMPs for marking clearing limits are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. Element #2 – Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. The specific BMPs related to establishing construction access that will be used on this project are identified in Appendix 8B. Alternate construction access BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. Weston Heights Technical Information Report Element #3 - Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. The specific BMPs for flow control that shall be used on this project are identified in Appendix 8B. Alternate flow control BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit. To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements (e.g. discharge to combined sewer systems). Element #4 - Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project are identified in Appendix 8B. Alternate sediment control BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs at the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize wash off of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas (BMP C240 paragraph 4, Volume II page 116). In some cases, sediment discharge in concentrated runoff can be controlled using permanent stormwater BMPs (e.g., infiltration swales, ponds, trenches). Sediment loads can limit the effectiveness of some permanent stormwater BMPs, such as those used for infiltration or biofiltration; however, those BMPs designed to remove solids by settling (wet ponds or detention ponds) can be used during the construction phase. When permanent stormwater BMPs will be used to control sediment discharge during construction, the structure will be protected from excessive sedimentation with adequate erosion and sediment control BMPs. Any accumulated sediment shall be removed after construction is complete and the permanent stormwater BMP will be restabilized with vegetation per applicable design requirements once the remainder of the site has been stabilized. Weston Heights Technical Information Report Element #5 - Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project are identified in Appendix 8B. Seeding will be used on disturbed areas that have reached final grade or that will remain unworked for more than thirty days. Plastic Covering will be used on the temporary stock pile areas and elsewhere on the site as needed. Dust control will be implemented as needed, to prevent it being required all roadways and driveways to be paved will receive early application of gravel base. Alternate soil stabilization BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. Element #6 - Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The specific BMPs that will be used to protect slopes for this project are identified in Appendix 8B. Alternate slope protection BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. Element #7 - Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP C220) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. The inlet protection measures to be applied on this project are identified in Appendix 8B. Weston Heights Technical Information Report If the primary BMP options are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D), or if no BMPs are listed above but deemed necessary during construction, the Certified Erosion and Sediment Control Lead shall implement one or more of the alternative BMP inlet protection options. Element #8 - Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project are identified in Appendix 8B. Alternate channel and outlet stabilization BMPs are included in Appendix 8C as a quick reference tool for the onsite inspector in the event the primary BMP(s) are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit (Appendix 8D). To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. The project site is located west of the Cascade Mountain Crest. As such, all temporary on- site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. Element #9 - Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well-organized, and free of debris. Any required BMPs to be implemented to control specific sources of pollutants are identified in Appendix 8B. The contractor shall implement the following measures as much as is practicable, in order to mitigate pollutant impacts from vehicles, construction equipment, and/or petroleum product storage/dispensing: All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. On-site fueling tanks and petroleum product storage containers shall include secondary containment. Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. Weston Heights Technical Information Report Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. The contractor shall implement the following concrete and grout pollution control measures: Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151). The contractor shall implement the following Solid Waste pollution control measures: Solid waste will be stored in secure, clearly marked containers. Element #10 - Control Dewatering Foundation, vault, and trench de-watering water, which shall have similar characteristics to stormwater runoff at the site, shall be discharged into a controlled conveyance system prior to discharge to a sediment trap, pond, or other specified facility. Channels must be stabilized as specified in Element #8. Clean, non-turbid de-watering water, such as well-point groundwater, can be discharged to systems tributary to state surface waters, provided the de-watering flow does not cause erosion or flooding of receiving waters. These clean waters should not be routed through stormwater sediment ponds. Highly turbid or contaminated dewatering water shall be handled separately from stormwater. Element #11 - Maintain BMPs All BMPs should be monitored and maintained regularly to ensure adequate operation. A TESC supervisor shall be identified at the beginning of the project to provide monitoring and direct the appropriate maintenance activity. As site conditions change, all BMPs shall be updated as necessary to maintain compliance with local regulations. Temporary BMPs can be removed when they are no longer needed. All temporary erosion and sediment control BMPs shall be removed within 30 days after construction is completed and the site is stabilized. Element #12 - Manage the Project Erosion and sediment control BMPs for this project have been designed based on the following principles: Design the project to fit the existing topography, soils, and drainage patterns. Emphasize erosion control rather than sediment control. Minimize the extent and duration of the area exposed. Keep runoff velocities low. Retain sediment on site. Thoroughly monitor site and maintain all ESC measures. Weston Heights Technical Information Report Schedule major earthwork during the dry season. As this project site is located west of the Cascade Mountain Crest, the project will be managed according to the following key project components: Phasing of Construction The construction project is being phased to the extent practicable in order to prevent soil erosion, and, to the maximum extent possible, the transport of sediment from the site during construction. Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities during each phase of construction, per the Scheduling BMP (C 162). Seasonal Work Limitations From October 1 through April 30, clearing, grading, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt- laden runoff will be prevented from leaving the site through a combination of the following: o Site conditions including existing vegetative coverage, slope, soil type, and proximity to receiving waters; and o Limitations on activities and the extent of disturbed areas; and o Proposed erosion and sediment control measures. Based on the information provided and/or local weather conditions, the local permitting authority may expand or restrict the seasonal limitation on site disturbance. The following activities are exempt from the seasonal clearing and grading limitations: o Routine maintenance and necessary repair of erosion and sediment control BMPs; o Routine maintenance of public facilities or existing utility structures that do not expose the soil or result in the removal of the vegetative cover to soil; and o Activities where there is 100 percent infiltration of surface water runoff within the site in approved and installed erosion and sediment control facilities. Coordination with Utilities and Other Jurisdictions Care has been taken to coordinate with utilities, other construction projects, and the local jurisdiction in preparing this SWPPP and scheduling the construction work. Inspection and Monitoring All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. This person has the necessary skills to: o Assess the site conditions and construction activities that could impact the quality of stormwater, and o Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. Weston Heights Technical Information Report A Certified Erosion and Sediment Control Lead shall be on-site or on-call at all times. Whenever inspection and/or monitoring reveals that the BMPs identified in this SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMPs or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP This SWPPP shall be retained on-site or within reasonable access to the site. The SWPPP shall be modified whenever there is a change in the design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the state. The SWPPP shall be modified if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The SWPPP shall be modified as necessary to include additional or modified BMPs designed to correct problems identified. Revisions to the SWPPP shall be completed within seven (7) days following the inspection. 3.2 – SITE SPECIFIC BMPs Site specific BMPs are shown on the TESC plan sheet(s) in Appendix 8A. 4.0 – CONSTRUCTION PHASING AND BMP IMPLEMENTATION The BMP implementation schedule will be driven by the construction schedule. The list below provides an estimate of the anticipated construction schedule. The project site is located west of the Cascade Mountain Crest. As such, the dry season is considered to be from May 1 to September 30, and the wet season is considered to be from October 1 to April 30. 5.0 – POLLUTION PREVENTION TEAM 5.1 ROLES AND RESPONSIBILITIES The pollution prevention team consists of personnel responsible for implementation of the SWPPP, including the following: Certified Erosion and Sediment Control Lead (CESCL) – primary contractor contact, responsible for site inspections (BMPs, visual monitoring, sampling, etc.); to be called upon in case of failure of any ESC measures. Resident Engineer – For projects with engineered structures only (sediment ponds/traps, sand filters, etc.): Site representative for the owner that is the project’s supervising engineer responsible for inspections and issuing instructions and drawings to the contractor’s site supervisor or representative. Emergency Ecology Contact – Individual to be contacted at Ecology in case of emergency. Emergency Owner Contact – Individual that is the site owner or representative of the site owner to be contacted in the case of an emergency. Non-Emergency Ecology Contact – Individual that is the site owner or representative of the site owner that can be contacted if required. Weston Heights Technical Information Report Monitoring Personnel – Personnel responsible for conducting water quality monitoring; for most sites this person is also the CESCL. 5.2 TEAM MEMBERS Names and contact information for those identified as members of the pollution prevention team are provided in the project summary in Appendix 8B. 6.0 – SITE INSPECTIONS AND MONITORING Monitoring includes visual inspection, monitoring for water quality parameters of concern, and documentation of the inspection and monitoring findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements; Site inspections; and, Stormwater quality monitoring. For convenience, the inspection forma and water quality monitoring forms included in Appendix 8E of this report include the required information for the site log book. This SWPPP may function as the site log book, if desired, or the forms may be separated and included in a separate site log book. However, if separated, the site log book must be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. 6.1 SITE INSPECTION All BMPs will be inspected, maintained, and repaired as needed to assure continued performance of their intended function. The inspector will be a Certified Erosion and Sediment Control Lead (CESCL) per BMP C160. The name and contact information for the CESCL is provided in Section 5 of this SWPPP. Site inspection will occur in all areas disturbed by construction activities and at all stormwater discharge points. Stormwater will be examined for the presence of suspended sediment, turbidity, discoloration, and oily sheen. The site inspector will evaluate and document the effectiveness of the installed BMPs and determine if it is necessary to repair or replace any of the BMPs to improve the quality of stormwater discharges. All maintenance and repairs will be documented in the site log book or forms provided in this document. All new BMPs or design changes will be documented in the SWPPP as soon as possible. 6.1.1 Site Inspection Frequency Site inspections will be conducted at least once a week and within 24 hours following any rainfall event which causes a discharge of stormwater from the site. For sites with temporary stabilization measures, the site inspection frequency can be reduced to once every month. 6.1.2 Site Inspection Documentation The site inspector will record each site inspection using the site log inspection forms provided in Appendix 8E. The site inspection log forms may be separated from this SWPPP document, but will be maintained on-site or within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Weston Heights Technical Information Report 6.2 Stormwater Quality Monitoring 6.2.1 Turbidity Sampling Monitoring requirements for the proposed project will include turbidity sampling to monitor site discharges for water quality compliance with the 2010 Snohomish County Drainage manual and Snohomish County Code Title 30.63A NPDES Construction Stormwater General Permit (Appendix 8D). Sampling will be conducted at all site discharge points at least once per calendar week. Turbidity monitoring will follow the analytical methodologies described in Section S4 of the 2005 Construction Stormwater General Permit (Appendix 8D). The key benchmark values that require action include 25 NTU and 250 NTU for turbidity. If the 25 NTU benchmark for turbidity is exceeded, the following steps will be conducted: 1. Ensure all BMPs specified in this SWPPP are installed and functioning as intended. 2. Assess whether additional BMPs should be implemented and make revisions to the SWPPP as necessary. 3. Sample the discharge location daily until the analysis results are less than 25 NTU (turbidity) or 32 cm (transparency). If the turbidity is greater than 25 NTU but less than 250 NTU for more than 3 days, additional treatment BMPs will be implemented within 24 hours of the third consecutive sample that exceeded the benchmark value. Additional treatment BMPs will include, but are not limited to, off-site treatment, infiltration, filtration and chemical treatment. If the 250 NTU benchmark for turbidity is exceeded at any time, the following steps will be conducted: 1. Notify Ecology by phone within 24 hours of analysis. 2. Continue daily sampling until the turbidity is less than 25 NTU. 3. Initiate additional treatment BMPs such as off-site treatment, infiltration, filtration and chemical treatment within 24 hours of the first 250 NTU exceedance. 4. Implement additional treatment BMPs as soon as possible, but within 7 days of the first 250 NTU exceedance. 5. Describe inspection results and remedial actions that are taken in the site log book and in monthly discharge monitoring reports. 6.2.2 pH Sampling Stormwater runoff will be monitored for pH starting on the first day of any activity that includes more than 40 yards of poured or recycled concrete, or after the application of “Engineered Soils” such as, Portland cement treated base, cement kiln dust, or fly ash. This does not include fertilizers. For concrete work, pH monitoring will start the first day concrete is poured and continue until 3 weeks after the last pour. For engineered soils, the pH monitoring period begins when engineered soils are first exposed to precipitation and continue until the area is fully stabilized. Weston Heights Technical Information Report Stormwater samples will be collected daily from all points of discharge from the site and measured for pH using a calibrated pH meter, pH test kit, or wide range pH indicator paper. If the measured pH is 8.5 or greater, the following steps will be conducted: 1. Prevent the high pH water from entering storm drains or surface water. 2. Adjust or neutralize the high pH water if necessary using appropriate technology such as CO2 sparging (liquid or dry ice). 3. Contact Ecology if chemical treatment other than CO2 sparging is planned. 7.0 – REPORTING AND RECORDKEEPING 7.1 RECORDKEEPING 7.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: A record of the implementation of the SWPPP and other permit requirements; Site inspections; and, Stormwater quality monitoring. For convenience, the inspection form and water quality monitoring forms included in Appendix 8E of this report include the required information for the site log book. 7.1.2 Records Retention Records of all monitoring information (site log book, inspection reports/checklists, etc.), this Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements will be retained during the life of the construction project and for a minimum of three years following the termination of permit coverage in accordance with permit condition S5.C. 7.1.3 Access to Plans and Records The SWPPP, General Permit, Notice of Authorization letter, and Site Log Book will be retained on site or within reasonable access to the site and will be made immediately available upon request to Ecology or the local jurisdiction. A copy of this SWPPP will be provided to Ecology within 14 days of receipt of a written request for the SWPPP from Ecology. Any other information requested by Ecology will be submitted within a reasonable time. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with permit condition S5.G. 7.1.4 Updating the SWPPP In accordance with Conditions S3, S4.B, and S9.B.3 of the General Permit, this SWPPP will be modified if the SWPPP is ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site or there has been a change in design, construction, operation, or maintenance at the site that has a significant effect on the discharge, or potential for discharge, of pollutants to the waters of the State. The SWPPP will be modified within seven days of determination based on inspection(s) that Weston Heights Technical Information Report additional or modified BMPs are necessary to correct problems identified, and an updated timeline for BMP implementation will be prepared. 7.2 REPORTING 7.2.1 Discharge Monitoring Reports Discharge Monitoring Report (DMR) forms will not be submitted to Ecology because water quality sampling is not being conducted at the site. 7.2.2 Notification of Noncompliance If any of the terms and conditions of the permit are not met, and it causes a threat to human health of the environment, the following steps will be taken in accordance with permit section S5.F: 1. Ecology will be immediately notified of the failure to comply. 2. Immediate action will be taken to control the noncompliance issue and to correct the problem. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. In accordance with permit condition S2.A, a complete application form will be submitted to Ecology and the appropriate local jurisdiction (if applicable) to be covered by the General Permit. Weston Heights Technical Information Report APPENDIX 8A SITE PLAN WITH BMP MEASURES Weston Heights Technical Information Report APPENDIX 8B SWPPP PROJECT SUMMARY Weston Heights Technical Information Report PROJECT TEAM MEMBERS: Title Name(s) Phone Number Certified Erosion & Sediment Control Lead Craig Sears (425) 869-1300 Resident Engineer Scott Mesic (425) 486-6533 Emergency Ecology Contact Puget Sound Office (425) 649-7000 Emergency Owner Contact Craig Sears (425) 869-1300 Non-Emergency Ecology Contact Northwest Region (425) 649-7000 Monitoring Personnel Craig Sears (425) 869-1300 ESTIMATED CONSTRUCTION SCHEDULE: Construction Start Date July 2016 Install ESC Measures July 2016 Construction End Date October 2016 CONSTRUCTION BMP LIST (Details following): Silt Fence (BMP C233) Stabilized Construction Entrance Storm Drain Inlet Protection (BMP C220) Materials on Hand (BMP C150) may also be applicable Detention Pond Or Vault Temporary and Permanent Seeding (BMP C120) Plastic Covering (BMP C123) Interceptor Dike and Swale (BMP C200) Check Dams (BMP C207) !"#$ %##!&#’#% ###% %##%#!(’ $#(# !" Weston Heights Technical Information Report APPENDIX 8C ALTERNATIVE BMPs Weston Heights Technical Information Report The following includes a list of possible alternative BMPs for each of the 12 elements not described in the main SWPPP text. This list can be referenced in the event a BMP for a specific element is not functioning as designed and an alternative BMP needs to be implemented. Element #1 - Mark Clearing Limits High Visibility Plastic or Metal Fence (BMP C103) Element #2 - Establish Construction Access Wheel Wash (BMP C106) Element #3 - Control Flow Rates (none) Element #4 - Install Sediment Controls Straw Bale Barrier (BMP C230) Vegetated Strip (BMP C234) Materials on Hand (BMP C150) Element #5 - Stabilize Soils Dust Control (BMP C140) Topsoiling (BMP C125) Sodding (BMP C124) Element #6 - Protect Slopes Straw Wattles (BMP C235) Grass-Lined Channels (BMP C201) Element #7 - Protect Drain Inlets (none) Element #8 - Stabilize Channels and Outlets Level Spreader (BMP C206) Element #10 - Control Dewatering (none) Weston Heights Technical Information Report APPENDIX 8D GENERAL PERMIT Weston Heights Technical Information Report Construction Stormwater General Permit At the time of submittal of this report, the project is within the public comment period for the Stormwater General Permit. The Department of Ecology has assigned the project the following General Permit Number: WAR304061 A copy of the construction stormwater general permit coverage documents will be added to this appendix during the preconstruction meeting. Weston Heights Technical Information Report APPENDIX 8E SITE LOG & INSPECTION FORMS Weston Heights Technical Information Report Site Inspection Forms (and Site Log) The results of each inspection shall be summarized in an inspection report or checklist that is entered into or attached to the site log book. It is suggested that the inspection report or checklist be included in this appendix to keep monitoring and inspection information in one document, but this is optional. However, it is mandatory that this SWPPP and the site inspection forms be kept onsite at all times during construction, and that inspections be performed and documented as outlined below. At a minimum, each inspection report or checklist shall include: a. Inspection date/times b. Weather information: general conditions during inspection, approximate amount of precipitation since the last inspection, and approximate amount of precipitation within the last 24 hours. c. A summary or list of all BMPs that have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. Locations of BMPs inspected, ii. Locations of BMPs that need maintenance, iii. The reason maintenance is needed iv. Locations of BMPs that failed to operate as designed or intended, and v. Locations where additional or different BMPs are needed, and the reason(s) why. e. A description of stormwater discharged from the site. The presence of suspended sediment, turbid water, discoloration, and/or oil sheen shall be noted, as applicable. f. A description of any water quality monitoring performed during inspection, and the results of that monitoring. g. General comments and notes, including a brief description of any BMP r repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the NPDES permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of person conducting the site inspection; and the following statement: “I certify under penalty of law that this report is true, accurate, and complete, to the best of my knowledge and belief”. When the site inspection indicates that the site is not in compliance with any terms and conditions of the NPDES permit, the Permittee shall take immediate action(s) to: stop, contain, and clean up the unauthorized discharges, or otherwise stop the noncompliance; correct the problem(s); implement appropriate Best Management Practices (BMPs), and/or conduct maintenance of existing BMPs; and achieve compliance with all applicable standards and permit conditions. In addition, if the noncompliance causes a threat to human health or the environment, the Permittee shall comply with the Noncompliance Notification requirements in Special Condition S5.F of the permit. Weston Heights Technical Information Report Site Inspection Form General Information Project Name: Inspector Name: Title: CESCL # : Date: Time: Inspection Type: □ After a rain event □ Weekly □ Turbidity/transparency benchmark exceedance □ Other Weather Precipitation Since last inspection In last 24 hours Description of General Site Conditions: Inspection of BMPs Element 1: Mark Clearing Limits BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 2: Establish Construction Access BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Weston Heights Technical Information Report Element 3: Control Flowrates BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 4: Install Sediment Controls BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 5: Stabilize Soils BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Weston Heights Technical Information Report Element 6: Protect Slopes BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 7: Protect Drain Inlets BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 8: Stabilize Channels and Outlets BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Weston Heights Technical Information Report Element 9: Control Pollutants BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Element 10: Control Dewatering BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP BMP: Location Inspected Functioning Problem/Corrective Action Y N Y N NIP Stormwater Discharges From the Site Observed? Problem/Corrective Action Y N Location Turbidity Discoloration Sheen Location Turbidity Discoloration Sheen Weston Heights Technical Information Report Water Quality Monitoring Was any water quality monitoring conducted? □Yes □No If water quality monitoring was conducted, record results here: If water quality monitoring indicated turbidity 250 NTU or greater; or transparency 6 cm or less, was Ecology notified by phone within 24 hrs? □Yes □No If Ecology was notified, indicate the date, time, contact name and phone number below: Date: Time: Contact Name: Phone #: General Comments and Notes Include BMP repairs, maintenance, or installations made as a result of the inspection. Were Photos Taken? □Yes □No If photos taken, describe photos below: Weston Heights Technical Information Report APPENDIX 8F TESC CALCULATIONS Weston Heights Technical Information Report West Basin – Developed Condition (Detained Basin) Flow Frequency Analysis Time Series File:west-15min.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.441 7 2/08/01 19:00 1.57 1 100.00 0.990 0.414 8 5/06/02 7:15 1.04 2 25.00 0.960 0.858 4 9/10/03 13:45 0.989 3 10.00 0.900 1.04 2 8/25/04 23:30 0.858 4 5.00 0.800 0.599 6 9/10/05 16:45 0.696 5 3.00 0.667 0.989 3 10/22/05 16:15 0.599 6 2.00 0.500 0.696 5 11/21/06 8:00 0.441 7 1.30 0.231 1.57 1 1/09/08 7:30 0.414 8 1.10 0.091 Computed Peaks 1.39 50.00 0.980 Per Section D.3.5.1 of the 2009 KCSWDM, the minimum pond surface area is calculated from the 2-yr peak flow calculated above as follows: SA(MIN) = 2,080 x Q2-yr SA(MIN) = 2,080 x 0.599 = 1,246 sf Weston Heights Technical Information Report East Basin – Developed Condition (Detained Basin) Flow Frequency Analysis Time Series File:east-15min.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.445 7 2/08/01 19:00 1.58 1 100.00 0.990 0.406 8 5/06/02 7:15 1.06 2 25.00 0.960 0.841 4 9/10/03 13:45 0.987 3 10.00 0.900 1.06 2 8/25/04 23:30 0.841 4 5.00 0.800 0.593 6 9/10/05 16:45 0.699 5 3.00 0.667 0.987 3 10/22/05 16:15 0.593 6 2.00 0.500 0.699 5 11/21/06 8:00 0.445 7 1.30 0.231 1.58 1 1/09/08 7:30 0.406 8 1.10 0.091 Computed Peaks 1.41 50.00 0.980 Per Section D.3.5.1 of the 2009 KCSWDM, the minimum pond surface area is calculated from the 2-yr peak flow calculated above as follows: SA(MIN) = 2,080 x Q2-yr SA(MIN) = 2,080 x 0.593 = 1,233 sf Weston Heights Technical Information Report SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT Weston Heights Technical Information Report Bond Quantities, Facilities Summaries, and Declaration of Covenant Bond Quantities have been provided at the City’s request. Storm drainage facilities are detailed on the engineering plans. Weston Heights Technical Information Report APPENDIX 9 BOND QUANTITY WORKSHEET Site Improvement Bond Quantity WorksheetS15 Web date: 04/03/2015Department of Permitting & Environmental Review35030 SE Douglas Street, Suite 210Snoqualmie, Washington 98065-9266206-296-6600 TTY Relay 711Project Name: Date: Location: Project No.: Activity No.: Note: All prices include labor, equipment, materials, overhead and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database._____________yesXno If yes, Forest Practice Permit Number: (RCW 76.09)Page 1 of 9Weston HeightsRenton, WAFor alternate formats, call 206-296-6600. __________________6/14/2016King County SI Bond Quantity Wsksht.xlsUnit prices updated: 3/2/2015 Version: 3/2/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetS15 Web date: 04/03/2015Unit # ofReference #Price Unit Quantity Applications CostEROSION/SEDIMENT CONTROLNumberBackfill & compaction-embankmentESC-16.00$ CYCheck dams, 4" minus rockESC-2SWDM 5.4.6.3 80.00$ Each 7 1560Crushed surfacing 1 1/4" minusESC-3WSDOT 9-03.9(3) 95.00$ CYDitchingESC-49.00$ CYExcavation-bulkESC-52.00$ CYFence, siltESC-6SWDM 5.4.3.1 1.50$ LF 1700 12550Fence, Temporary (NGPE)ESC-71.50$ LFHydroseedingESC-8SWDM 5.4.2.4 0.80$ SY 12000 19600Jute MeshESC-9SWDM 5.4.2.2 3.50$ SYMulch, by hand, straw, 3" deepESC-10SWDM 5.4.2.1 2.50$ SYMulch, by machine, straw, 2" deepESC-11SWDM 5.4.2.1 2.00$ SYPiping, temporary, CPP, 6"ESC-1212.00$ LFPiping, temporary, CPP, 8"ESC-1314.00$ LFPiping, temporary, CPP, 12"ESC-1418.00$ LFPlastic covering, 6mm thick, sandbaggedESC-15SWDM 5.4.2.3 4.00$ SY 100 1400Rip Rap, machine placed; slopesESC-16WSDOT 9-13.1(2) 45.00$ CYRock Construction Entrance, 50'x15'x1'ESC-17SWDM 5.4.4.1 1,800.00$ Each 2 13600Rock Construction Entrance, 100'x15'x1'ESC-18SWDM 5.4.4.1 3,200.00$ EachSediment pond riser assemblyESC-19SWDM 5.4.5.2 2,200.00$ EachSediment trap, 5' high berm ESC-20SWDM 5.4.5.1 19.00$ LFSed. trap, 5' high, riprapped spillway berm section ESC-21SWDM 5.4.5.1 70.00$ LFSeeding, by handESC-22SWDM 5.4.2.4 1.00$ SYSodding, 1" deep, level groundESC-23SWDM 5.4.2.5 8.00$ SYSodding, 1" deep, sloped groundESC-24SWDM 5.4.2.5 10.00$ SYTESC SupervisorESC-25110.00$ HR 1 909900Water truck, dust controlESC-26SWDM 5.4.7 140.00$ HRWRITE-IN-ITEMS **** (see page 9)EachESC SUBTOTAL:26,610.00$ 30% CONTINGENCY & MOBILIZATION:7,983.00$ ESC TOTAL:34,593.00$ COLUMN:APage 2 of 9King County SI Bond Quantity Wsksht.xlsUnit prices updated: 3/2/2015 Version: 3/2/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future Public PrivateRight-of-Way Right of Way ImprovementsUnit Price Unit Quant. Cost Quant. Cost Quant. CostGENERAL ITEMSNo.Backfill & Compaction- embankment GI - 1 6.00$ CYBackfill & Compaction- trench GI - 2 9.00$ CYClear/Remove Brush, by hand GI - 3 1.00$ SYClearing/Grubbing/Tree Removal GI - 4 10,000.00$ Acre 0.09 900.00 0.28 2,800.00 2.52 25,200.00Excavation - bulk GI - 5 2.00$ CY 1645 3,290.00 4071 8,142.00Excavation - Trench GI - 6 5.00$ CY 155 775.00 600 3,000.00Fencing, cedar, 6' high GI - 7 20.00$ LFFencing, chain link, vinyl coated, 6' high GI - 8 20.00$ LF400 8,000.00Fencing, chain link, gate, vinyl coated, 20GI - 9 1,400.00$ Each1 1,400.00Fencing, split rail, 3' high GI - 10 15.00$ LFFill & compact - common barrow GI - 11 25.00$ CY6580 164,500.00Fill & compact - gravel base GI - 12 27.00$ CYFill & compact - screened topsoil GI - 13 39.00$ CYGabion, 12" deep, stone filled mesh GI - 14 65.00$ SYGabion, 18" deep, stone filled mesh GI - 15 90.00$ SYGabion, 36" deep, stone filled mesh GI - 16 150.00$ SYGrading, fine, by hand GI - 17 2.50$ SYGrading, fine, with grader GI - 18 2.00$ SYMonuments, 3' long GI - 19 250.00$ Each 1 250.00 2 500.00Sensitive Areas Sign GI - 20 7.00$ Each9 63.00Sodding, 1" deep, sloped ground GI - 21 8.00$ SYSurveying, line & grade GI - 22 850.00$ Day2 1,700.00Surveying, lot location/lines GI - 23 1,800.00$ Acre3 5,400.00Traffic control crew ( 2 flaggers ) GI - 24 120.00$ HRTrail, 4" chipped wood GI - 25 8.00$ SYTrail, 4" crushed cinder GI - 26 9.00$ SYTrail, 4" top course GI - 27 12.00$ SYWall, retaining, concrete GI - 28 55.00$ SFWall, rockery GI - 29 15.00$ SF300 4,500.00Page 3 of 9 SUBTOTAL 1,150.00 6,865.00 222,405.00 & Drainage Facilities*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future PublicRight-of-way Right of Way ImprovementsUnit Price Unit Quant. Cost Quant. Cost Quant. CostROAD IMPROVEMENTNo.AC Grinding, 4' wide machine < 1000sy RI - 1 30.00$ SYAC Grinding, 4' wide machine 1000-2000 RI - 2 16.00$ SYAC Grinding, 4' wide machine > 2000sy RI - 3 10.00$ SYAC Removal/Disposal RI - 4 35.00$ SY 805 28,175.00 100 3,500.00Barricade, type III ( Permanent ) RI - 6 56.00$ LFCurb & Gutter, rolled RI - 7 17.00$ LFCurb & Gutter, vertical RI - 8 12.50$ LF 600 7,500.00Curb and Gutter, demolition and disposal RI - 9 18.00$ LFCurb, extruded asphalt RI - 10 5.50$ LFCurb, extruded concrete RI - 11 7.00$ LF 150 1,050.00Sawcut, asphalt, 3" depth RI - 12 1.85$ LF 700 1,295.00Sawcut, concrete, per 1" depth RI - 13 3.00$ LFSealant, asphalt RI - 14 2.00$ LF 600 1,200.00 300 600.00Shoulder, AC, ( see AC road unit price ) RI - 15 -$ SYShoulder, gravel, 4" thick RI - 16 15.00$ SYSidewalk, 4" thick RI - 17 38.00$ SY 315 11,970.00Sidewalk, 4" thick, demolition and disposaRI - 18 32.00$ SYSidewalk, 5" thick RI - 19 41.00$ SYSidewalk, 5" thick, demolition and disposaRI - 20 40.00$ SYSign, handicap RI - 21 85.00$ EachStriping, per stall RI - 22 7.00$ EachStriping, thermoplastic, ( for crosswalk ) RI - 23 3.00$ SFStriping, 4" reflectorized line RI - 24 0.50$ LF 600 300.00 250 125.00Page 4 of 9 SUBTOTAL 30,970.00 24,745.00Private & Drainage Facilities*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future Public PrivateRight-of-way Right of Way ImprovementsUnit Price Unit Quant. Cost Quant. Cost Quant. CostROAD SURFACING No. (4" Rock = 2.5 base & 1.5" top course) 9 1/2" Rock= 8" base & 1.5" top course)Additional 2.5" Crushed Surfacing RS - 1 3.60$ SYHMA 1/2" Overlay, 1.5" RS - 2 14.00$ SYHMA 1/2" Overlay 2" RS - 3 18.00$ SYHMA Road, 2", 4" rock, First 2500 SY RS - 4 28.00$ SYHMA Road, 2", 4" rock, Qty. over 2500 SYRS - 5 21.00$ SYHMA Road, 3", 9 1/2" Rock, First 2500 SYRS - 6 35.00$ SYHMA Road, 3", 9 1/2" Rock, Qty Over 250RS - 7 42.00$ SYNot Used RS - 8Not Used RS - 9HMA Road, 6" Depth, First 2500 SY RS - 10 33.10$ SY 350 11,585.00 650 21,515.00 1200 39,720.00HMA Road, 6" Depth, Qty. Over 2500 SYRS - 11 30.00$ SYHMA 3/4" or 1", 4" Depth RS - 12 20.00$ SYGravel Road, 4" rock, First 2500 SY RS - 13 15.00$ SY200 3,000.00Gravel Road, 4" rock, Qty. over 2500 SY RS - 14 10.00$ SYPCC Road (Add Under Write-Ins w/DesigRS - 15Thickened Edge RS - 17 8.60$ LF350 3,010.00Page 5 of 9 SUBTOTAL 11,585.00 21,515.00 45,730.00 & Drainage Facilities*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future Public PrivateRight-of-way Right of Way ImprovementsUnit Price Unit Quant. Cost Quant. Cost Quant. CostDRAINAGE (CPP = Corrugated Plastic Pipe, N12 or Equivalent)Access Road, R/D D - 1 21.00$ SY 100 2,100.00Bollards - fixed D - 2 240.74$ EachBollards - removable D - 3 452.34$ Each* (CBs include frame and lid)CB Type I D - 4 1,500.00$ Each 11 16,500.00CB Type IL D - 5 1,750.00$ EachCB Type II, 48" diameter D - 6 2,300.00$ Each for additional depth over 4' D - 7 480.00$ FTCB Type II, 54" diameter D - 8 2,500.00$ Each 2 5,000.00 for additional depth over 4' D - 9 495.00$ FT 11 5,445.00CB Type II, 60" diameter D - 10 2,800.00$ Each for additional depth over 4' D - 11 600.00$ FTCB Type II, 72" diameter D - 12 3,600.00$ Each for additional depth over 4' D - 13 850.00$ FTThrough-curb Inlet Framework (Add) D - 14 400.00$ Each 1 400.00Cleanout, PVC, 4" D - 15 150.00$ EachCleanout, PVC, 6" D - 16 170.00$ Each 16 2,720.00Cleanout, PVC, 8" D - 17 200.00$ EachCulvert, PVC, 4" D - 18 10.00$ LFCulvert, PVC, 6" D - 19 13.00$ LFCulvert, PVC, 8" D - 20 15.00$ LFCulvert, PVC, 12" D - 21 23.00$ LFCulvert, CMP, 8" D - 22 19.00$ LFCulvert, CMP, 12" D - 23 29.00$ LFCulvert, CMP, 15" D - 24 35.00$ LFCulvert, CMP, 18" D - 25 41.00$ LFCulvert, CMP, 24" D - 26 56.00$ LFCulvert, CMP, 30" D - 27 78.00$ LFCulvert, CMP, 36" D - 28 130.00$ LFCulvert, CMP, 48" D - 29 190.00$ LFCulvert, CMP, 60" D - 30 270.00$ LFCulvert, CMP, 72" D - 31 350.00$ LFPage 6 of 9 SUBTOTAL 32,165.00 & Drainage Facilities For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future Public PrivateRight-of-way Right of Way ImprovementsDRAINAGE CONTINUEDNo. Unit Price Unit Quant. Cost Quant. Cost Quant. CostCulvert, Concrete, 8" D - 32 25.00$ LFCulvert, Concrete, 12" D - 33 36.00$ LFCulvert, Concrete, 15" D - 34 42.00$ LFCulvert, Concrete, 18" D - 35 48.00$ LFCulvert, Concrete, 24" D - 36 78.00$ LFCulvert, Concrete, 30" D - 37 125.00$ LFCulvert, Concrete, 36" D - 38 150.00$ LFCulvert, Concrete, 42" D - 39 175.00$ LFCulvert, Concrete, 48" D - 40 205.00$ LFCulvert, CPP, 6" D - 41 14.00$ LFCulvert, CPP, 8" D - 42 16.00$ LFCulvert, CPP, 12" D - 43 24.00$ LF 1554 37296Culvert, CPP, 15" D - 44 35.00$ LFCulvert, CPP, 18" D - 45 41.00$ LFCulvert, CPP, 24" D - 46 56.00$ LFCulvert, CPP, 30" D - 47 78.00$ LFCulvert, CPP, 36" D - 48 130.00$ LFDitching D - 49 9.50$ CYFlow Dispersal Trench (1,436 base+) D - 50 28.00$ LF 50 2836French Drain (3' depth) D - 51 26.00$ LFGeotextile, laid in trench, polypropylene D - 52 3.00$ SYMid-tank Access Riser, 48" dia, 6' deep D - 54 2,000.00$ EachPond Overflow Spillway D - 55 16.00$ SY 16 256Restrictor/Oil Separator, 12" D - 56 1,150.00$ EachRestrictor/Oil Separator, 15" D - 57 1,350.00$ EachRestrictor/Oil Separator, 18" D - 58 1,700.00$ EachRiprap, placed D - 59 42.00$ CY 10 420Tank End Reducer (36" diameter) D - 60 1,200.00$ EachTrash Rack, 12" D - 61 350.00$ Each 2 700Trash Rack, 15" D - 62 410.00$ EachTrash Rack, 18" D - 63 480.00$ EachTrash Rack, 21" D - 64 550.00$ EachPage 7 of 9 SUBTOTAL41508 & Drainage Facilities*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Existing Future Public PrivateRight-of-way Right of Way ImprovementsUnit Price Unit Quant. Price Quant. Cost Quant. CostPARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrow PL - 1 21.00$ SY NA NA2" AC, 1.5" top course & 2.5" base coursPL - 2 28.00$ SY NA NA4" select borrow PL - 3 5.00$ SY NA NA1.5" top course rock & 2.5" base course PL - 4 14.00$ SY NA NAUTILITY POLES & STREET LIGHTINGUtility pole relocation costs must be accompanied by Franchise Utility's Cost EstimateUtility Pole(s) Relocation UP-1Street Light Poles w/Luminaires UP-2 EachWRITE-IN-ITEMS(Such as detention/water quality vaults.)No.West Vault WI - 1 ######### EA 1 150,000.00Stormfilter WI - 2 23,000.00$ EA 1 23,000.00WI - 3 CYWI - 4 LFWI - 5 FTWI - 6WI - 7WI - 8WI - 9WI - 10SUBTOTAL 173,000.00SUBTOTAL (SUM ALL PAGES):43,705.00 299,798.00 268,135.0030% CONTINGENCY & MOBILIZATION:13,111.50 89,939.40 80,440.50 GRANDTOTAL: 56,816.50 389,737.40 348,575.50COLUMN: B C DPage 8 of 9Lump Sum & Drainage FacilitiesNot To Be Used For Roads Or Shoulders*KCC 27A authorizes only one bond reduction.King County SI Bond Quantity Wsksht.xlsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Site Improvement Bond Quantity WorksheetWeb date: 04/03/2015Original 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 Right of Way & Drainage Facilities (C)Private Improvements (D)Calculated Quantity CompletedTotal Right-of Way and/or Site Restoration Bond*/** (A+B)(First $7,500 of bond* shall be cash.Performance Bond* Amount (A+B+C+D) = TOTAL (T) T x 0.30Minimum is $2000. Minimum is $2000.Maintenance/Defect Bond* TotalMinimum is $2000.NAME OF PERSON PREPARING BOND* REDUCTION:Date:* NOTE:The word "bond" as used in this document means a financial guarantee acceptable to King County.** NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition, corrective work, both on- and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged, some estimated costs for restoration needs to be reflected in this amount. The 30% contingency and mobilization costs are computed in this quantity.*** NOTE: Per KCC 27A, total bond amounts remaining after reduction shall not be less than 30% of the original amount (T) or as revised by major design changes.REQUIRED BOND* AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY KING COUNTY FINANCIAL GUARANTEE REQUIREMENTSPUBLIC ROAD & DRAINAGE MAINTENANCE/DEFECT BOND*PERFORMANCE BOND*AMOUNTMINIMUM BOND* AMOUNT REQUIRED FOR RECORDING ORTEMPORARY OCCUPANCY AT SUBSTANTIAL COMPLETION ***111,638.5$ 34,593.0$ 56,816.5$ 389,737.4$ 248,916.7$ (B+C) x 0.25 =91,409.5$ 348,575.5$ 829,722.4$ Page 9 of 9King County SI Bond Quantity Wsksht.xlsCheck out the DDES Web site at www.kingcounty.gov/permitsUnit prices updated: 03/02/2015Version: 03/02/2015Report Date: 6/14/2016 Weston Heights Technical Information Report SECTION 10 OPERATIONS AND MAINTENANCE MANUAL Weston Heights Technical Information Report Operations and Maintenance Manual PERFORATED PIPE CONNECTION Roof/footing drain lines, including perforated pipe connections shall be kept open and clean. If the pipes appear to be clogged, they should be cleaned by high pressure flushing with water or flexible sewer rods. In cases where roots effectively block the drainage, the use of herbicides may be indicated. Whatever method of cleaning is used, consideration for erosion and sediment control is needed. DISPERSION TRENCH Perforated pipes in dispersion trenches shall be kept open and clean. If the pipes appear to be clogged, they should be cleaned by high pressure flushing with water or flexible sewer rods. In cases where roots effectively block the drainage, the use of herbicides may be indicated. Whatever method of cleaning is used, consideration for erosion and sediment control is needed. The top of the dispersion trench should be kept free of leaves, debris, soil, moss, and other sources of clogging. If the surface or drain-rock becomes clogged, it should be excavated and replaced. The following pages are selections from Appendix A of the 2009 King County Stormwater Design Manual, applicable to this project: 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-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 1/3the 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 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 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-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.