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Weston Heights North TIR Utility III Comments
October 5, 2016 Weston Heights North Technical Information Report 702 Nile Ave NE, Renton, WA SDA Project #349-007-15 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 North Technical Information Report Weston Heights North 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 10/5/16 R:\Projects\349 (prospect development)\007-15 (Weston North)\Technical\Reports\2016-10-05 TIR\2016-10-05 WHN Drainage Report.docm 10-05-16 Weston Heights North 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 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 North Technical Information Report SECTION 1 PROJECT OVERVIEW Weston Heights North Technical Information Report Project Overview The Weston Heights North project proposes the construction of 6 single family lots (1 existing single family residence to remain with 5 new lots) on two existing parcels totaling approximately 2.47 acres. Frontage improvements along both Nile Ave NE and NE 7th Pl, as well utility connections to the site are also proposed. The project occupies King County Tax Parcel Numbers 11230590002 and 947794TR-L, and is situated in the southwest quarter of Section 11, Township 28 North, Range 5 East, W.M. More specifically, the project is located on the east side of Nile Ave NE and south side of NE 7th Pl, approximately 0.4 miles north of the intersection of Nile Ave and NE 4th Street. A vicinity map has been provided as Figure 2 of this document. The Weston Heights North project is situated immediately north of the Weston Heights development, which will be built under a separate permit, #U15-006162. Drainage design for the Weston Heights project accompanies much of the proposed development for the Weston Heights North project. For this reason, this report is very reflective of the Weston Heights TIR. The majority of land cover within the Weston Heights North project limits has been previously developed. The western region currently houses a single family residence, a detached Quonset hut, shed and garage. Of these existing structures, only the shed will be removed as part of this project. The surrounding areas of the structures feature typical residential lawn and landscaping. The eastern region has been previously cleared of the historic forested vegetation and is currently all grassed area with no tree canopy. The wetland and area to the east of the wetland, outwards to the projects eastern border, remain forested. The topography of the combined subject parcel slopes moderately from east to west, with the southcentral section sloping inwards towards the wetland. 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. Surface runoff will be detained through three separate facilities in order to avoid concentration of flows. Two of the facilities are located on the Weston Heights development site – a combined detention vault (west) and a detention pond (east). The third facility is located north of the Weston Heights North project, across NE 7th Pl, on the Olympus Villa development – a combined detention pond. 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. Both the west combined detention vault, and the Olympus Villa combined detention pond discharge overland into the ditch, located at the southwestern corner of the Weston Heights project. This meets the requirements for Full Drainage Review, as described further in Section 4 of this report. A wetland is located in the southcentral region of the project. This wetland and its surrounding buffer will remain undisturbed. In order to satisfy Core Requirements #3 and #8 of the 2009 King County Stormwater Design Manual (KCSDM), a large amount of the projects predeveloped (existing condition) contributing areas are diverted away from the central wetland in the developed condition. An end goal of this project is to ensure the existing wetland hydroperiod is satisfied in the developed condition. Surface runoff will receive water quality treatment through three separate facilities in order to satisfy Core Requirement #8. A stormfilter vault provides water quality prior to entering the Weston Heights east detention pond. The two combined detention facilities, the Olympus Villa Pond and the Weston Heights west vault, provide dead storage to allow particulates to settle out of the flow path. Weston Heights North 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 North Technical Information Report FIGURE 2 VICINITY MAP Weston Heights North Technical Information Report SECTION 2 CONDITIONS AND REQUIREMENTS SUMMARY Weston Heights North 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 Weston Heights east detention pond, and the Olympus Villa Pond. No additional storm sewer infrastructure is proposed to utilize the Weston Heights west combined detention vault. The Weston Heights east detention facility will discharge via level spreader into the existing wetland, maintaining the pre-developed surface water discharge location. The Olympus Villa Pond maintains its current overland discharge, which is into a swale at the southwest corner of the Weston Heights project. This discharge location is also the discharge location of the Weston Heights west vault. These discharge locations maintain the natural discharge locations of the predeveloped scenario. 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 three detention facilities – the Weston Heights east detention pond (originally designed to accommodate Weston North lots 4-6, will now only accommodate Weston North Lots 5-6, and the impervious area of lot 4 as a result of this project), the Weston Heights west combined detention vault (originally designed to mitigate against the released yard/landscape bypass areas of Weston North lots 2-3, will now mitigate against the released yard/landscape bypass areas of Weston North lots 2-4), and the Olympus Villa Pond ‘A’ (serves the frontage improvements on NE 7th Pl, as well as roof areas from Weston North lots 2-3). An in-depth discussion of the design methodologies may be found in Section 4, Part D, of this report. Design calculations for these facility are contained in Appendix 4A of this report. A developed basins figure is provided in Appendix 4A. 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 North Technical Information Report Core Requirement #8 – Water Quality Surface runoff generated atop the Weston Heights North areas receive runoff treatment through three separate facilities – two combined detention facilities (wetpool), and a Stormfilter vault (sediment removal via cartridge). A discussion of the design methodology for water quality is provided in Section 4, Part E, of this document. Accompanying calculations may be found in Appendix 4B. A developed treatment basins figure is provided in Appendix 4B. 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 1123059002 and 947794TR-L. 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 3B 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 North Technical Information Report SECTION 3 OFFSITE ANALYSIS Weston Heights North Technical Information Report Task 1 – Study Area Definitions and Maps The project’s study area includes the subject parcels, 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 southcentral portion 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 North 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 Weston Heights 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. This is the same ditch into which Olympus Villa Pond ‘A’ ultimately discharges. 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 NE. There is a closed depression located at the southeast corner of the existing Quonset hut in Lot 1, with a small, circular contributing area. The east half of the project generally falls toward the west or north, and is collected in the wetland area in the center of the project, or flows out to NE 7th Place. Water from the wetland enters an overflow device just north of Orcas Ave W, then is conveyed to the Nile Ave NE roadside ditch. 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 North Technical Information Report APPENDIX 3A DOWNSTREAM ANALYSIS MAP AND PHOTOS Project Site 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 North Technical Information Report APPENDIX 3B RESOURCE REVIEW DOCUMENTS Soil Map—King County Area, Washington (Weston North) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/4/2016 Page 1 of 35260210526028052603505260420526049052605605260630526028052603505260420526049052605605260630564330564400564470564540564610564680564750564820564890564960 564330 564400 564470 564540 564610 564680 564750 564820 564890 564960 47° 29' 45'' N 122° 8' 45'' W47° 29' 45'' N122° 8' 14'' W47° 29' 31'' N 122° 8' 45'' W47° 29' 31'' 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 11, Sep 14, 2015 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 North) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/4/2016 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 3.6 100.0% Totals for Area of Interest 3.6 100.0% Soil Map—King County Area, Washington Weston North Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/4/2016 Page 3 of 3 Weston Heights North Technical Information Report SECTION 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Weston Heights North Technical Information Report Part A – Existing Site Hydrology The project site, including the Weston Heights development, is effectively split into two distinct basins by a central wetland area. For stormwater modeling purposes, the Weston Heights 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 majority of land cover in the Weston North project limits has been developed. The western region currently houses a single family residence, a detached Quonset hut, shed and garage. As a result of this project, only the existing shed will be removed. The surrounding areas of the structures feature typical residential landscaping. The eastern region has been previously cleared of the historic forested vegetation and is currently all grassed area with no tree canopy. The wetland and area to the east of the wetland, outwards to the projects eastern border, remain forested. The topography of the combined subject parcel slopes moderately from east to west, with the southcentral section sloping inwards towards the wetland. 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). For purposes of the wetland hydroperiod analysis, the existing conditions consist of forested, lawn/landscape, and pastured areas. Part B – Developed Site Hydrology The project proposes 6 single family lots (1 lot to remain with 5 new lots proposed) with associated utility connections. Lot 1 will remain undisturbed, but a gravel trench will be installed to collect surface runoff flowing east towards Nile Ave, and will route the collected runoff to the north to an existing type 2 catch basin located at the intersection of Nile Ave and NE 7th Pl. This will maintain the downstream discharge location of the existing runoff, without contributing to the west vault, as this project does not require stormwater management for the undisturbed area of Lot 1. An existing French drain at the northern end of Lot 1 will be redirected to tie into an existing catch basin in NE 7th Pl, routed around the west vault. As with the gravel trench, this will maintain the downstream discharge location of the existing runoff without contributing to the west vault. The remainder of the site will be developed, featuring 5 lots with a maximum impervious surface coverage of 40% per lot. The existing wetland, and associated buffer, will remain undisturbed. Except for one, the existing trees bordering the northern end of the wetland, stretched across the south end of the subject parcel, will remain undisturbed. Additional yard/landscaping vegetation will be planted for site beautification. The existing downstream discharge location will be maintained through the developed 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 must match or reduce the predeveloped durations for the range of 50% of the 2-year peak flow up to the full 50-year peak flow, and also match or reduce the predeveloped 2-yr and 10-yr peak flows. King County Runoff Time Series (KCRTS) was utilized in analyzing the flow control standards for this project. 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. KCRTS was used for analyzing the treatment volume for the east Stormfilter vault, following the design methods prescribed in Section 6.5.5.1 of the 2009 KCSWDM. Wetpool design was completed following the design methods prescribed in Section 6.4.1.1 of the 2009 KCSWDM. Weston Heights North Technical Information Report This project is also subject to ensuring the existing wetland hydroperiod is satisfied in the developed condition. The goal is to ensure that the existing conditions hydroperiod is matched in the developed conditions, achieving a maximum/minimum 15% change per day for an entire calendar year, and a 10% change each month in a calendar year. WWHM2012, a continuous simulation modeling software approved by the Washington Department of Ecology for stormwater modeling in Washington State, was utilized for the analysis of the wetland hydroperiod. Part D – Flow Control System The Weston Heights flow control facilities and the Olympus Villa Pond ‘A’ are utilized for this projects separate basins (separate basins in one similar threshold discharge area). For this reason, the text in this Section has been, to an extent, plagiarized from the Weston Heights TIR, #U15-006162. 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 Weston Heights North (yard/landscape area of Lots 2-4), and one on the south west side of the site (the Weston Height’s project). The landscaping/yard area on the Weston Heights North lots 2-3 is not feasibly routed to the east detention pond, and there is not capacity in Olympus Villa Pond ‘A’. To satisfy the wetland hydroperiod, lot 4 has also been released. 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 design for the Weston Heights project required the entire area to be considered bypass; however, the impervious area on these lots are being directed to the Olympus Villa Pond as part of the Weston Heights North project, rendering the Weston Heights west vault oversized). 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 (on the southwest corner of the Weston Heights project). 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’, Weston Heights North lots 4-6 (40% impervious area on lot 4, and entire area on lots 5-6), as well as the east bypass basin (the design for the Weston Heights project required this area to be considered bypass; however, this area is now being directed to the Olympus Villa Pond as part of the Weston Heights North project, rendering the Weston Heights east pond oversized). 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. Ultimately, the east pond is oversized. 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 the Weston Heights North project to utilize the constructed pond. 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, as well as the impervious areas of Weston Heights North lots 2-3, to Olympus Villa Pond ‘A’. The ultimate discharge of Pond ‘A’ is the same point as the discharge for the west underground detention vault. The Weston Heights North project does not require any reconstruction of the existing Olympus Villa Pond, but will require a new control structure riser and orifices to meet the required flow control standards. All facilities have been designed using King County Runoff Time Series (KCRTS) stormwater runoff modeling software. The calculations for the west and east basin have been provided for reference only, Weston Heights North Technical Information Report and have previously been approved during the Weston Height’s project reviews. Refer to Appendix 4A for “Flow Control Design Calculations”. Part E – Water Quality System The Weston Heights water quality facilities and the Olympus Villa Pond ‘A’ are utilized for this projects separate basins (separate basins in one similar threshold discharge area). For this reason, the text in this Section has been plagiarized from the Weston Heights TIR, with a few edits. 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 Weston Heights design accounted for the built-out conditions of the Weston Heights North project along Nile Ave. The east basin Stormfilter system, upstream of the detention pond, provides removal of suspended solids via cartridges. The roof areas from Weston Heights North lots 4-6, and Weston Heights lots 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 these lots. The yard/landscape areas of Weston Heights North lots 5-6 will be collected via yard drains, connected to the roof drain system, and will also be routed around the Stormfilter. Again, these areas are not pollution generating, and do not mix with pollution generating runoff. The disturbed yard/landscape areas on Weston Heights lots 10-12 will receive water quality treatment from the Stormfilter vault. The Olympus Villa Pond ‘A’ contains 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. The impervious areas from Weston Heights North lots 2-3 will be routed to the Olympus Villa Pond, in addition to all frontage improvements along NE 7th Pl. 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. The calculations for the west vault deadpool storage, and the east basin Stormfilter Cartridge have been provided as for reference only and have been previously approved during the Weston Height’s project reviews. 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 75-feet and 50-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 Heights 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 a portion of the western most extents of the Weston Heights North project (Lot 1), in addition to the wetland 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 and Weston Heights, predeveloped runoff will be directed away from the wetland in order to satisfy flow control and water quality requirements. In order to satisfy the existing wetland hydroperiod, the runoff Weston Heights North Technical Information Report from the yard/landscape areas of Weston North lots 2-4 will be allowed to release into the wetland, to the back of the lot. Refer to Appendix 4C for “Wetland Hydroperiod Calculations”. Weston Heights North Technical Information Report APPENDIX 4A FLOW CONTROL DESIGN CALCULATIONS UNDISTURBEDWETLANDAREAWESTBASINUNDISTURBEDAREAEASTBASINWESTON HEIGHTS NORTHWESTON HEIGHTS NORTHWESTON HEIGHTSWESTON HEIGHTSDateProject No.DrawnDesignSheet:JDAEWJ6/9/16349-007-15PREDEVELOPED BASIN MAPWESTON HEIGHTS NORTH NEXISTING WEST BASINEXISTING EAST BASIN*EXISTING OLYMPUS VILLA POND 'A' BASINWESTON HEIGHTS NORTH TO OLYMPUS VILLA PRIVATE ROAD C TRACT CTRACT BWEST BASINEAST BASINWESTON NORTHLOT #'S 4-6WESTBYPASSBASINWESTON NORTHLOT #'S 2 & 3EAST BYPASSBASINWESTON HEIGHTS NORTHWESTON NORTHLOT #4DateProject No.DrawnDesignSheet:JDAEWJ6/06/16349-007-15DEVELOPED BASIN MAPWESTON HEIGHTS NORTHNWEST PROJECT BASINWEST BYPASS BASINNOTES:*DEVELOPED OLYMPUS VILLA POND 'A'DEVELOPED TO OLYMPUS VILLA POND 'A' Weston Heights North Technical Information Report KCSWDM – SCALE FACTOR Weston Heights North 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 North 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 0.379 4 2/09/01 2:00 0.690 1 100.00 0.990 0.225 8 12/03/01 17:00 0.457 2 25.00 0.960 0.379 5 9/10/03 15:00 0.439 3 10.00 0.900 0.439 3 8/26/04 1:00 0.379 4 5.00 0.800 0.362 7 10/28/04 18:00 0.379 5 3.00 0.667 0.376 6 10/22/05 17:00 0.376 6 2.00 0.500 0.457 2 11/21/06 9:00 0.362 7 1.30 0.231 0.690 1 1/09/08 7:00 0.225 8 1.10 0.091 Computed Peaks 0.612 50.00 0.980 Weston Heights North 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 0.060 3 2/09/01 2:00 0.122 1 100.00 0.990 0.026 8 12/03/01 17:00 0.073 2 25.00 0.960 0.037 7 2/28/03 16:00 0.060 3 10.00 0.900 0.054 4 8/26/04 1:00 0.054 4 5.00 0.800 0.043 6 10/28/04 18:00 0.044 5 3.00 0.667 0.044 5 10/22/05 17:00 0.043 6 2.00 0.500 0.073 2 11/21/06 9:00 0.037 7 1.30 0.231 0.122 1 1/09/08 7:00 0.026 8 1.10 0.091 Computed Peaks 0.106 50.00 0.980 Weston Heights North 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 Weston Heights North Technical Information Report 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 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 8.60 514.40 26419. 0.607 4.120 0.00 8.70 514.50 26726. 0.614 4.300 0.00 8.80 514.60 27034. 0.621 4.470 0.00 8.90 514.70 27341. 0.628 4.630 0.00 9.00 514.80 27648. 0.635 4.790 0.00 9.10 514.90 27955. 0.642 4.940 0.00 9.20 515.00 28262. 0.649 5.090 0.00 9.30 515.10 28570. 0.656 5.240 0.00 Weston Heights North Technical Information Report Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 0.69 0.50 7.61 513.41 23381. 0.537 2 0.46 0.12 7.10 512.90 21810. 0.501 3 0.38 0.12 7.03 512.83 21603. 0.496 4 0.44 0.03 2.79 508.59 8572. 0.197 5 0.26 0.07 4.74 510.54 14560. 0.334 6 0.23 0.07 4.70 510.50 14426. 0.331 7 0.38 0.05 4.03 509.83 12368. 0.284 8 0.18 0.02 1.92 507.72 5910. 0.136 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.50 0.12 ******** 0.25 0.57 2 0.12 0.07 ******** ******* 0.16 3 0.12 0.06 ******** ******* 0.16 4 0.03 0.05 ******** ******* 0.08 5 0.07 0.04 ******** ******* 0.10 6 0.07 0.03 ******** ******* 0.09 7 0.05 0.04 ******** ******* 0.06 8 0.02 0.02 ******** ******* 0.04 ---------------------------------- Route Time Series through Facility Inflow Time Series File:west-dev.tsf Outflow Time Series File:West-RDOut POC Time Series File:West-DSOut Inflow/Outflow Analysis Peak Inflow Discharge: 0.689 CFS at 7:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.506 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: 23381. Cu-Ft : 0.537 Ac-Ft Add Time Series:west-byp.tsf Peak Summed Discharge: 0.574 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:West-DSOut.tsf Flow Duration from Time Series File:west-rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.002 27471 44.799 44.799 55.201 0.552E+00 0.005 6578 10.727 55.527 44.473 0.445E+00 0.009 7702 12.560 68.087 31.913 0.319E+00 0.012 7188 11.722 79.809 20.191 0.202E+00 0.016 4326 7.055 86.864 13.136 0.131E+00 0.019 3308 5.395 92.259 7.741 0.774E-01 0.022 1987 3.240 95.499 4.501 0.450E-01 0.026 1140 1.859 97.358 2.642 0.264E-01 0.029 927 1.512 98.870 1.130 0.113E-01 0.033 196 0.320 99.189 0.811 0.811E-02 0.036 13 0.021 99.211 0.789 0.789E-02 0.040 10 0.016 99.227 0.773 0.773E-02 0.043 44 0.072 99.299 0.701 0.701E-02 0.046 45 0.073 99.372 0.628 0.628E-02 0.050 47 0.077 99.449 0.551 0.551E-02 0.053 55 0.090 99.538 0.462 0.462E-02 0.057 40 0.065 99.604 0.396 0.396E-02 0.060 51 0.083 99.687 0.313 0.313E-02 0.064 31 0.051 99.737 0.263 0.263E-02 0.067 42 0.068 99.806 0.194 0.194E-02 Weston Heights North Technical Information Report 0.070 10 0.016 99.822 0.178 0.178E-02 0.074 7 0.011 99.834 0.166 0.166E-02 0.077 8 0.013 99.847 0.153 0.153E-02 0.081 10 0.016 99.863 0.137 0.137E-02 0.084 11 0.018 99.881 0.119 0.119E-02 0.088 10 0.016 99.897 0.103 0.103E-02 0.091 15 0.024 99.922 0.078 0.783E-03 0.094 9 0.015 99.936 0.064 0.636E-03 0.098 1 0.002 99.938 0.062 0.620E-03 0.101 4 0.007 99.945 0.055 0.554E-03 0.105 3 0.005 99.949 0.051 0.506E-03 0.108 5 0.008 99.958 0.042 0.424E-03 0.112 4 0.007 99.964 0.036 0.359E-03 0.115 5 0.008 99.972 0.028 0.277E-03 0.118 6 0.010 99.982 0.018 0.179E-03 0.122 7 0.011 99.993 0.007 0.652E-04 Flow Duration from Time Series File:west-dsout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.002 27749 45.253 45.253 54.747 0.547E+00 0.007 8375 13.658 58.911 41.089 0.411E+00 0.011 8345 13.609 72.520 27.480 0.275E+00 0.016 6497 10.595 83.115 16.885 0.169E+00 0.021 4412 7.195 90.310 9.690 0.969E-01 0.025 2569 4.189 94.499 5.501 0.550E-01 0.030 1414 2.306 96.805 3.195 0.319E-01 0.034 878 1.432 98.237 1.763 0.176E-01 0.039 381 0.621 98.858 1.142 0.114E-01 0.043 118 0.192 99.051 0.949 0.949E-02 0.048 71 0.116 99.167 0.833 0.833E-02 0.053 74 0.121 99.287 0.713 0.713E-02 0.057 62 0.101 99.388 0.612 0.612E-02 0.062 48 0.078 99.467 0.533 0.533E-02 0.066 53 0.086 99.553 0.447 0.447E-02 0.071 59 0.096 99.649 0.351 0.351E-02 0.075 42 0.068 99.718 0.282 0.282E-02 0.080 34 0.055 99.773 0.227 0.227E-02 0.085 25 0.041 99.814 0.186 0.186E-02 0.089 13 0.021 99.835 0.165 0.165E-02 0.094 11 0.018 99.853 0.147 0.147E-02 0.098 8 0.013 99.866 0.134 0.134E-02 0.103 7 0.011 99.878 0.122 0.122E-02 0.108 14 0.023 99.901 0.099 0.995E-03 0.112 7 0.011 99.912 0.088 0.881E-03 0.117 6 0.010 99.922 0.078 0.783E-03 0.121 9 0.015 99.936 0.064 0.636E-03 0.126 6 0.010 99.946 0.054 0.538E-03 0.130 4 0.007 99.953 0.047 0.473E-03 0.135 6 0.010 99.962 0.038 0.375E-03 0.140 6 0.010 99.972 0.028 0.277E-03 0.144 5 0.008 99.980 0.020 0.196E-03 0.149 5 0.008 99.989 0.011 0.114E-03 0.153 5 0.008 99.997 0.003 0.326E-04 0.158 0 0.000 99.997 0.003 0.326E-04 0.162 1 0.002 99.998 0.002 0.163E-04 Weston Heights North Technical Information Report 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 0.046 | 0.93E-02 0.87E-02 -6.2 | 0.93E-02 0.046 0.044 -4.1 0.057 | 0.61E-02 0.61E-02 0.8 | 0.61E-02 0.057 0.057 0.8 0.068 | 0.40E-02 0.42E-02 6.2 | 0.40E-02 0.068 0.069 1.6 0.078 | 0.26E-02 0.24E-02 -7.4 | 0.26E-02 0.078 0.077 -1.1 0.089 | 0.17E-02 0.17E-02 0.0 | 0.17E-02 0.089 0.089 0.0 0.100 | 0.12E-02 0.13E-02 9.9 | 0.12E-02 0.100 0.104 4.9 0.110 | 0.88E-03 0.91E-03 3.7 | 0.88E-03 0.110 0.112 2.1 0.121 | 0.70E-03 0.64E-03 -9.3 | 0.70E-03 0.121 0.119 -1.8 0.131 | 0.49E-03 0.44E-03 -10.0 | 0.49E-03 0.131 0.129 -1.5 0.142 | 0.31E-03 0.24E-03 -21.1 | 0.31E-03 0.142 0.138 -2.8 0.153 | 0.15E-03 0.82E-04 -44.4 | 0.15E-03 0.153 0.146 -4.4 0.163 | 0.98E-04 0.00E+00 -100.0 | 0.98E-04 0.163 0.151 -7.5 0.174 | 0.49E-04 0.00E+00 -100.0 | 0.49E-04 0.174 0.153 -12.1 0.185 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.185 0.163 -11.7 Maximum positive excursion = 0.006 cfs ( 5.7%) occurring at 0.099 cfs on the Base Data:west-pre.tsf and at 0.104 cfs on the New Data:west-dsout.tsf Maximum negative excursion = 0.029 cfs (-16.1%) occurring at 0.182 cfs on the Base Data:west-pre.tsf and at 0.153 cfs on the New Data:west-dsout.tsf Weston Heights North 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 North 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 North 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 North 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 North 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 North 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 North 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 North Technical Information Report Equivalent East Pond Detention Storage Weston Heights North 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 North 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 North Technical Information Report Olympus Village Pond ‘A’ Revised Riser Design (see stage/storage equivalent area worksheet) Retention/Detention Facility Type of Facility: Detention Pond Side Slope: 2.36 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: 10992. sq. ft 0.252 acres Effective Storage Depth: 4.93 ft Stage 0 Elevation: 0.00 ft Storage Volume: 38611. 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 3.40 1.63 0.089 4.0 3 4.10 1.39 0.048 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 6130. 0.50 0.50 3009. 0.069 0.021 0.00 6206. 0.60 0.60 3633. 0.083 0.023 0.00 6282. 0.70 0.70 4265. 0.098 0.024 0.00 6359. 0.80 0.80 4905. 0.113 0.026 0.00 6436. 0.90 0.90 5552. 0.127 0.028 0.00 6514. 1.00 1.00 6208. 0.143 0.029 0.00 6592. 1.10 1.10 6871. 0.158 0.031 0.00 6670. 1.20 1.20 7542. 0.173 0.032 0.00 6749. 1.30 1.30 8221. 0.189 0.033 0.00 6829. 1.40 1.40 8907. 0.204 0.035 0.00 6909. 1.50 1.50 9602. 0.220 0.036 0.00 6989. 1.60 1.60 10305. 0.237 0.037 0.00 7070. 1.70 1.70 11016. 0.253 0.038 0.00 7151. 1.80 1.80 11735. 0.269 0.039 0.00 7233. 1.90 1.90 12463. 0.286 0.040 0.00 7315. 2.00 2.00 13198. 0.303 0.041 0.00 7397. 2.10 2.10 13942. 0.320 0.042 0.00 7480. 2.20 2.20 14694. 0.337 0.043 0.00 7564. Weston Heights North Technical Information Report 2.30 2.30 15455. 0.355 0.044 0.00 7647. 2.40 2.40 16224. 0.372 0.045 0.00 7732. 2.50 2.50 17001. 0.390 0.046 0.00 7817. 2.60 2.60 17787. 0.408 0.047 0.00 7902. 2.70 2.70 18582. 0.427 0.048 0.00 7987. 2.80 2.80 19385. 0.445 0.049 0.00 8073. 2.90 2.90 20196. 0.464 0.050 0.00 8160. 3.00 3.00 21017. 0.482 0.051 0.00 8247. 3.10 3.10 21846. 0.502 0.052 0.00 8334. 3.20 3.20 22684. 0.521 0.052 0.00 8422. 3.30 3.30 23530. 0.540 0.053 0.00 8511. 3.40 3.40 24386. 0.560 0.054 0.00 8599. 3.42 3.42 24558. 0.564 0.055 0.00 8617. 3.43 3.43 24644. 0.566 0.056 0.00 8626. 3.45 3.45 24817. 0.570 0.059 0.00 8644. 3.47 3.47 24990. 0.574 0.063 0.00 8662. 3.48 3.48 25077. 0.576 0.068 0.00 8671. 3.50 3.50 25250. 0.580 0.074 0.00 8688. 3.52 3.52 25424. 0.584 0.080 0.00 8706. 3.54 3.54 25598. 0.588 0.082 0.00 8724. 3.64 3.64 26475. 0.608 0.091 0.00 8814. 3.74 3.74 27361. 0.628 0.098 0.00 8904. 3.84 3.84 28256. 0.649 0.105 0.00 8995. 3.94 3.94 29160. 0.669 0.111 0.00 9086. 4.04 4.04 30073. 0.690 0.116 0.00 9178. 4.10 4.10 30626. 0.703 0.120 0.00 9233. 4.11 4.11 30718. 0.705 0.121 0.00 9242. 4.13 4.13 30903. 0.709 0.123 0.00 9261. 4.14 4.14 30996. 0.712 0.125 0.00 9270. 4.16 4.16 31181. 0.716 0.129 0.00 9288. 4.17 4.17 31274. 0.718 0.133 0.00 9298. 4.19 4.19 31460. 0.722 0.138 0.00 9316. 4.20 4.20 31554. 0.724 0.141 0.00 9325. 4.22 4.22 31740. 0.729 0.143 0.00 9344. 4.32 4.32 32679. 0.750 0.154 0.00 9437. 4.42 4.42 33628. 0.772 0.164 0.00 9530. 4.52 4.52 34585. 0.794 0.172 0.00 9624. 4.62 4.62 35552. 0.816 0.180 0.00 9718. 4.72 4.72 36529. 0.839 0.187 0.00 9812. 4.82 4.82 37515. 0.861 0.194 0.00 9907. 4.92 4.92 38510. 0.884 0.201 0.00 10003. 4.93 4.93 38611. 0.886 0.202 0.00 10012. 5.03 5.03 39617. 0.909 0.516 0.00 10108. 5.13 5.13 40632. 0.933 1.090 0.00 10205. 5.23 5.23 41658. 0.956 1.820 0.00 10302. 5.33 5.33 42693. 0.980 2.620 0.00 10399. 5.43 5.43 43737. 1.004 2.910 0.00 10497. 5.53 5.53 44792. 1.028 3.170 0.00 10595. 5.63 5.63 45856. 1.053 3.410 0.00 10694. 5.73 5.73 46931. 1.077 3.630 0.00 10793. 5.83 5.83 48015. 1.102 3.840 0.00 10892. 5.93 5.93 49109. 1.127 4.040 0.00 10992. 6.03 6.03 50213. 1.153 4.230 0.00 11093. 6.13 6.13 51328. 1.178 4.410 0.00 11194. 6.23 6.23 52452. 1.204 4.580 0.00 11295. 6.33 6.33 53587. 1.230 4.750 0.00 11397. 6.43 6.43 54732. 1.256 4.910 0.00 11499. 6.53 6.53 55887. 1.283 5.070 0.00 11601. 6.63 6.63 57052. 1.310 5.220 0.00 11705. 6.73 6.73 58227. 1.337 5.370 0.00 11808. 6.83 6.83 59413. 1.364 5.510 0.00 11912. 6.93 6.93 60610. 1.391 5.650 0.00 12016. Weston Heights North 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 40176. 0.922 2 0.63 ******* 0.21 4.93 4.93 38634. 0.887 3 0.76 ******* 0.16 4.38 4.38 33259. 0.764 4 0.79 ******* 0.16 4.41 4.41 33534. 0.770 5 0.51 ******* 0.05 2.86 2.86 19902. 0.457 6 0.67 ******* 0.10 3.84 3.84 28230. 0.648 7 0.66 ******* 0.05 3.37 3.37 24106. 0.553 8 0.54 ******* 0.04 2.14 2.14 14216. 0.326 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 0.73E-02 -2.8 | 0.76E-02 0.053 0.053 -0.3 0.066 | 0.56E-02 0.50E-02 -10.6 | 0.56E-02 0.066 0.055 -16.1 0.078 | 0.43E-02 0.45E-02 5.3 | 0.43E-02 0.078 0.082 4.5 0.091 | 0.32E-02 0.34E-02 5.0 | 0.32E-02 0.091 0.092 1.7 0.103 | 0.25E-02 0.24E-02 -4.0 | 0.25E-02 0.103 0.102 -1.1 0.116 | 0.18E-02 0.15E-02 -19.1 | 0.18E-02 0.116 0.110 -5.2 0.128 | 0.12E-02 0.11E-02 -8.1 | 0.12E-02 0.128 0.121 -5.5 0.141 | 0.91E-03 0.10E-02 12.5 | 0.91E-03 0.141 0.146 3.6 0.153 | 0.59E-03 0.78E-03 33.3 | 0.59E-03 0.153 0.160 4.2 0.166 | 0.36E-03 0.42E-03 18.2 | 0.36E-03 0.166 0.168 1.7 0.178 | 0.18E-03 0.24E-03 36.4 | 0.18E-03 0.178 0.189 5.9 0.191 | 0.13E-03 0.15E-03 12.5 | 0.13E-03 0.191 0.193 1.4 0.203 | 0.82E-04 0.16E-04 -80.0 | 0.82E-04 0.203 0.198 -2.3 0.216 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.216 0.209 -2.9 Maximum positive excursion = 0.012 cfs ( 6.9%) occurring at 0.177 cfs on the Base Data:predev.tsf and at 0.189 cfs on the New Data:ov_rdout.tsf Maximum negative excursion = 0.011 cfs (-16.6%) occurring at 0.066 cfs on the Base Data:predev.tsf and at 0.055 cfs on the New Data:ov_rdout.tsf Weston Heights North Technical Information Report KCRTS Duration Analysis Equivalent Olympus Villa Pond ‘A’ Dimensions/Side Slope Weston Heights North Technical Information Report APPENDIX 4B WATER QUALITY DESIGN CALCULATIONS Weston Heights North Technical Information Report KCSWDM – SCALE FACTOR Weston Heights North Technical Information Report East Basin Stormfilter Treatment Calculations: Weston Heights North 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 North Technical Information Report East Basin Stormfilter Cartridge Calculations: Weston Heights North 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 North 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 North Technical Information Report APPENDIX 4C WETLAND HYDROPERIOD CALCULATIONS 11230590026389300030638930002094779402109477940220947794023094779402409477940250947794026023168000802316800090231680010023168001102316800120112305907811230590671023059026770820117010230590211023059259UNDISTURBEDWETLANDAREA*(0.69 AC)DateProject No.DrawnDesignSheet:JDAEWJ6/9/16349-007-15EXISTING WETLANDHYDROPERIODWESTON HEIGHTS NORTH NEXISTING WETLAND HYDROPERIOD BASINLEGEND UNDISTURBEDWETLANDAREA*(0.69 AC)PRIVATE ROAD C TRACT CTRACT BDateProject No.DrawnDesignSheet:JDAEWJ6/9/16349-007-15DEVELOPEDWETLAND HYDROPERIODWESTON HEIGHTS NORTH NDEVELOPED WETLAND HYDROPERIOD BASINLEGEND Weston Heights North Technical Information Report WWHM2012 – Wetland Fluctuation Report WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Wetland Hydroperiod_160819 Site Name: Weston Heights Site Address: Nile Ave City : Renton Report Date: 8/22/2016 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, Pasture, Flat 1.11 C, Lawn, Flat .39 Pervious Total 3.89 Impervious Land Use Acres ROADS FLAT 0.08 Impervious Total 0.08 Basin Total 3.97 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Weston Heights North Technical Information Report MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use Acres C, Forest, Mod 2.9 C, Lawn, Flat .65 Pervious Total 3.55 Impervious Land Use Acres ROADS FLAT 0.01 Impervious Total 0.01 Basin Total 3.56 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:3.89 Total Impervious Area:0.08 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:3.55 Total Impervious Area:0.01 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.233418 5 year 0.3834 10 year 0.50244 25 year 0.676036 50 year 0.82273 100 year 0.984778 Weston Heights North Technical Information Report Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.203648 5 year 0.339672 10 year 0.446348 25 year 0.599849 50 year 0.727785 100 year 0.867412 ___________________________________________________________________ ___________________________________________________________________ Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. ___________________________________________________________________ Wetlands Fluctuation for POC 1 Average Annual Volume (acft) Month Predevel Mitigated Percent Pass/Fail Jan 78.3945 69.7526 89.0 Pass Feb 60.3779 53.9874 89.4 Pass Mar 52.0230 46.5417 89.5 Pass Apr 32.8923 29.4753 89.6 Pass May 18.1558 16.2840 89.7 Pass Jun 13.6557 12.1765 89.2 Pass Jul 9.9351 8.9121 89.7 Pass Aug 8.5343 7.6195 89.3 Pass Sep 7.8502 6.8865 87.7 Pass Oct 13.2939 11.4173 85.9 Pass Nov 44.0823 37.9292 86.0 Pass Dec 68.8057 60.6908 88.2 Pass Day Predevel Mitigated Percent Pass/Fail Jan1 2.5290 2.2280 88.1 Pass 2 2.5255 2.2539 89.2 Pass 3 2.3425 2.0761 88.6 Pass 4 2.6598 2.3533 88.5 Pass 5 2.7156 2.4153 88.9 Pass 6 2.8314 2.5127 88.7 Pass 7 2.6417 2.3545 89.1 Pass 8 2.6261 2.3407 89.1 Pass 9 2.2953 2.0411 88.9 Pass 10 2.1420 1.9069 89.0 Pass 11 2.3071 2.0528 89.0 Pass 12 2.3805 2.1075 88.5 Pass 13 2.8048 2.4814 88.5 Pass 14 2.8566 2.5491 89.2 Pass 15 2.5984 2.3177 89.2 Pass 16 2.6192 2.3346 89.1 Pass 17 2.5648 2.2791 88.9 Pass 18 2.8229 2.5125 89.0 Pass 19 2.7355 2.4392 89.2 Pass 20 2.5419 2.2693 89.3 Pass Weston Heights North Technical Information Report 21 2.3420 2.0878 89.1 Pass 22 2.5038 2.2160 88.5 Pass 23 2.8083 2.4955 88.9 Pass 24 2.6131 2.3392 89.5 Pass 25 2.3052 2.0607 89.4 Pass 26 2.3014 2.0573 89.4 Pass 27 2.2754 2.0316 89.3 Pass 28 2.3830 2.1211 89.0 Pass 29 2.5943 2.3158 89.3 Pass 30 2.5292 2.2484 88.9 Pass 31 2.5244 2.2596 89.5 Pass Feb1 2.3127 2.0693 89.5 Pass 2 2.0954 1.8804 89.7 Pass 3 2.0800 1.8636 89.6 Pass 4 1.8403 1.6519 89.8 Pass 5 1.9556 1.7430 89.1 Pass 6 2.1025 1.8814 89.5 Pass 7 2.4735 2.2024 89.0 Pass 8 2.5045 2.2458 89.7 Pass 9 2.1291 1.9089 89.7 Pass 10 1.8681 1.6727 89.5 Pass 11 2.0436 1.8166 88.9 Pass 12 2.1007 1.8780 89.4 Pass 13 1.9256 1.7232 89.5 Pass 14 2.0637 1.8370 89.0 Pass 15 2.2474 2.0010 89.0 Pass 16 2.2766 2.0305 89.2 Pass 17 2.1992 1.9566 89.0 Pass 18 2.5587 2.2819 89.2 Pass 19 2.3831 2.1411 89.8 Pass 20 2.1359 1.9119 89.5 Pass 21 2.0010 1.7945 89.7 Pass 22 1.9371 1.7324 89.4 Pass 23 2.0741 1.8533 89.4 Pass 24 2.0327 1.8190 89.5 Pass 25 1.9075 1.7116 89.7 Pass 26 2.0129 1.8026 89.5 Pass 27 2.0247 1.8096 89.4 Pass 28 2.1626 1.9353 89.5 Pass 29 1.8307 1.6363 89.4 Pass Mar1 1.7944 1.6044 89.4 Pass 2 1.9939 1.7744 89.0 Pass 3 2.0400 1.8246 89.4 Pass 4 2.1310 1.9027 89.3 Pass 5 1.8375 1.6555 90.1 Pass 6 1.6862 1.5138 89.8 Pass 7 1.6026 1.4265 89.0 Pass 8 1.8304 1.6283 89.0 Pass 9 1.8817 1.6805 89.3 Pass 10 1.8625 1.6587 89.1 Pass 11 2.0555 1.8294 89.0 Pass 12 1.8934 1.6999 89.8 Pass 13 1.7587 1.5750 89.6 Pass 14 1.7959 1.6036 89.3 Pass 15 1.6764 1.5024 89.6 Pass 16 1.7046 1.5320 89.9 Pass 17 1.6663 1.4899 89.4 Pass Weston Heights North Technical Information Report 18 1.6238 1.4600 89.9 Pass 19 1.4782 1.3271 89.8 Pass 20 1.3381 1.2060 90.1 Pass 21 1.4894 1.3244 88.9 Pass 22 1.6365 1.4592 89.2 Pass 23 1.6134 1.4433 89.5 Pass 24 1.5651 1.4067 89.9 Pass 25 1.4526 1.3020 89.6 Pass 26 1.3982 1.2528 89.6 Pass 27 1.3184 1.1801 89.5 Pass 28 1.3779 1.2305 89.3 Pass 29 1.3895 1.2441 89.5 Pass 30 1.3006 1.1671 89.7 Pass 31 1.2532 1.1224 89.6 Pass Apr1 1.1711 1.0473 89.4 Pass 2 1.1860 1.0633 89.7 Pass 3 1.4154 1.2613 89.1 Pass 4 1.5446 1.3845 89.6 Pass 5 1.3864 1.2439 89.7 Pass 6 1.1975 1.0797 90.2 Pass 7 1.2012 1.0739 89.4 Pass 8 1.2843 1.1474 89.3 Pass 9 1.1747 1.0567 90.0 Pass 10 1.1229 1.0032 89.3 Pass 11 1.1038 0.9874 89.5 Pass 12 1.1511 1.0252 89.1 Pass 13 1.1047 0.9892 89.5 Pass 14 1.0284 0.9231 89.8 Pass 15 1.1629 1.0364 89.1 Pass 16 1.2209 1.0973 89.9 Pass 17 0.9842 0.8899 90.4 Pass 18 1.1194 0.9899 88.4 Pass 19 1.2142 1.0959 90.3 Pass 20 0.9795 0.8862 90.5 Pass 21 0.9267 0.8285 89.4 Pass 22 1.1033 0.9857 89.3 Pass 23 0.9788 0.8812 90.0 Pass 24 0.8674 0.7831 90.3 Pass 25 0.7723 0.6981 90.4 Pass 26 0.7892 0.7021 89.0 Pass 27 0.7692 0.6931 90.1 Pass 28 0.8030 0.7156 89.1 Pass 29 0.8755 0.7838 89.5 Pass 30 0.8512 0.7631 89.7 Pass May1 0.7920 0.7133 90.1 Pass 2 0.7125 0.6434 90.3 Pass 3 0.6983 0.6266 89.7 Pass 4 0.7218 0.6486 89.9 Pass 5 0.7120 0.6383 89.6 Pass 6 0.6621 0.5973 90.2 Pass 7 0.6049 0.5467 90.4 Pass 8 0.5887 0.5304 90.1 Pass 9 0.5900 0.5307 89.9 Pass 10 0.6148 0.5475 89.0 Pass 11 0.5619 0.5058 90.0 Pass 12 0.5953 0.5351 89.9 Pass 13 0.5931 0.5292 89.2 Pass Weston Heights North Technical Information Report 14 0.5736 0.5148 89.7 Pass 15 0.5655 0.5089 90.0 Pass 16 0.5303 0.4762 89.8 Pass 17 0.5324 0.4762 89.4 Pass 18 0.5649 0.5023 88.9 Pass 19 0.5628 0.5068 90.0 Pass 20 0.5176 0.4669 90.2 Pass 21 0.5117 0.4623 90.3 Pass 22 0.5037 0.4499 89.3 Pass 23 0.4907 0.4381 89.3 Pass 24 0.4697 0.4238 90.2 Pass 25 0.4685 0.4138 88.3 Pass 26 0.4703 0.4229 89.9 Pass 27 0.4797 0.4315 90.0 Pass 28 0.5177 0.4589 88.6 Pass 29 0.5581 0.4939 88.5 Pass 30 0.5403 0.4811 89.0 Pass 31 0.5307 0.4720 88.9 Pass Jun1 0.5607 0.5007 89.3 Pass 2 0.5651 0.4981 88.1 Pass 3 0.5532 0.4874 88.1 Pass 4 0.4908 0.4398 89.6 Pass 5 0.4987 0.4410 88.4 Pass 6 0.5827 0.5151 88.4 Pass 7 0.5406 0.4802 88.8 Pass 8 0.5423 0.4816 88.8 Pass 9 0.5504 0.4910 89.2 Pass 10 0.4972 0.4424 89.0 Pass 11 0.4773 0.4259 89.2 Pass 12 0.4434 0.4017 90.6 Pass 13 0.4154 0.3753 90.3 Pass 14 0.4085 0.3658 89.5 Pass 15 0.4157 0.3711 89.3 Pass 16 0.4300 0.3795 88.3 Pass 17 0.4188 0.3771 90.0 Pass 18 0.3996 0.3586 89.8 Pass 19 0.3956 0.3519 89.0 Pass 20 0.4190 0.3736 89.2 Pass 21 0.4094 0.3694 90.2 Pass 22 0.3974 0.3561 89.6 Pass 23 0.4417 0.3830 86.7 Pass 24 0.4126 0.3737 90.6 Pass 25 0.3854 0.3481 90.3 Pass 26 0.3721 0.3340 89.8 Pass 27 0.3694 0.3290 89.1 Pass 28 0.3667 0.3276 89.4 Pass 29 0.3651 0.3256 89.2 Pass 30 0.3814 0.3381 88.7 Pass Jul1 0.3682 0.3285 89.2 Pass 2 0.3583 0.3212 89.6 Pass 3 0.3481 0.3138 90.1 Pass 4 0.3479 0.3105 89.3 Pass 5 0.3384 0.3053 90.2 Pass 6 0.3373 0.3010 89.2 Pass 7 0.3403 0.3034 89.2 Pass 8 0.3404 0.3018 88.7 Pass 9 0.3343 0.2993 89.5 Pass Weston Heights North Technical Information Report 10 0.3255 0.2939 90.3 Pass 11 0.3332 0.2954 88.6 Pass 12 0.3339 0.3005 90.0 Pass 13 0.3302 0.2969 89.9 Pass 14 0.3200 0.2919 91.2 Pass 15 0.3321 0.2914 87.7 Pass 16 0.3187 0.2881 90.4 Pass 17 0.3120 0.2828 90.6 Pass 18 0.3106 0.2788 89.7 Pass 19 0.3067 0.2757 89.9 Pass 20 0.3021 0.2724 90.2 Pass 21 0.3029 0.2714 89.6 Pass 22 0.2984 0.2685 90.0 Pass 23 0.2945 0.2658 90.3 Pass 24 0.2930 0.2638 90.0 Pass 25 0.3006 0.2645 88.0 Pass 26 0.2915 0.2626 90.1 Pass 27 0.2885 0.2599 90.1 Pass 28 0.2838 0.2568 90.5 Pass 29 0.2821 0.2546 90.3 Pass 30 0.2803 0.2534 90.4 Pass 31 0.2834 0.2538 89.6 Pass Aug1 0.2833 0.2520 88.9 Pass 2 0.2917 0.2607 89.4 Pass 3 0.2815 0.2535 90.1 Pass 4 0.2751 0.2497 90.8 Pass 5 0.2822 0.2506 88.8 Pass 6 0.2813 0.2486 88.4 Pass 7 0.2707 0.2462 90.9 Pass 8 0.2760 0.2449 88.7 Pass 9 0.2670 0.2420 90.6 Pass 10 0.2658 0.2386 89.8 Pass 11 0.2633 0.2361 89.7 Pass 12 0.2599 0.2338 90.0 Pass 13 0.2751 0.2433 88.4 Pass 14 0.2834 0.2546 89.8 Pass 15 0.2682 0.2451 91.4 Pass 16 0.2687 0.2434 90.6 Pass 17 0.2766 0.2472 89.4 Pass 18 0.2698 0.2404 89.1 Pass 19 0.2600 0.2351 90.4 Pass 20 0.2627 0.2314 88.1 Pass 21 0.2676 0.2326 86.9 Pass 22 0.2916 0.2511 86.1 Pass 23 0.2902 0.2564 88.4 Pass 24 0.2850 0.2574 90.3 Pass 25 0.2898 0.2600 89.7 Pass 26 0.2869 0.2523 87.9 Pass 27 0.2701 0.2402 88.9 Pass 28 0.2718 0.2392 88.0 Pass 29 0.2712 0.2455 90.5 Pass 30 0.2645 0.2341 88.5 Pass 31 0.2610 0.2290 87.7 Pass Sep1 0.2587 0.2270 87.8 Pass 2 0.2498 0.2213 88.6 Pass 3 0.2566 0.2243 87.4 Pass 4 0.2445 0.2184 89.3 Pass Weston Heights North Technical Information Report 5 0.2513 0.2196 87.4 Pass 6 0.2369 0.2142 90.4 Pass 7 0.2474 0.2166 87.5 Pass 8 0.2433 0.2185 89.8 Pass 9 0.2502 0.2159 86.3 Pass 10 0.2423 0.2138 88.2 Pass 11 0.2415 0.2186 90.5 Pass 12 0.2382 0.2113 88.7 Pass 13 0.2470 0.2106 85.3 Pass 14 0.2364 0.2071 87.6 Pass 15 0.2394 0.2086 87.1 Pass 16 0.2803 0.2332 83.2 Pass 17 0.2631 0.2371 90.1 Pass 18 0.2640 0.2341 88.7 Pass 19 0.2589 0.2303 89.0 Pass 20 0.2544 0.2311 90.8 Pass 21 0.3025 0.2593 85.7 Pass 22 0.3624 0.3107 85.7 Pass 23 0.3105 0.2659 85.6 Pass 24 0.2759 0.2368 85.9 Pass 25 0.2694 0.2337 86.7 Pass 26 0.2593 0.2245 86.6 Pass 27 0.2698 0.2410 89.3 Pass 28 0.2546 0.2280 89.6 Pass 29 0.2808 0.2462 87.7 Pass 30 0.2655 0.2401 90.4 Pass Oct1 0.2608 0.2347 90.0 Pass 2 0.2614 0.2274 87.0 Pass 3 0.2836 0.2362 83.3 Pass 4 0.2912 0.2511 86.2 Pass 5 0.5374 0.4538 84.4 Pass 6 0.4648 0.4078 87.7 Pass 7 0.4451 0.3693 83.0 Pass 8 0.4666 0.3848 82.5 Pass 9 0.4773 0.3904 81.8 Pass 10 0.3800 0.3288 86.5 Pass 11 0.3196 0.2729 85.4 Pass 12 0.3132 0.2652 84.7 Pass 13 0.2901 0.2461 84.8 Pass 14 0.2847 0.2502 87.9 Pass 15 0.2809 0.2454 87.3 Pass 16 0.3233 0.2757 85.3 Pass 17 0.3544 0.3126 88.2 Pass 18 0.4044 0.3501 86.6 Pass 19 0.6225 0.5275 84.7 Pass 20 0.7340 0.6411 87.3 Pass 21 0.5691 0.4996 87.8 Pass 22 0.4773 0.4257 89.2 Pass 23 0.4255 0.3748 88.1 Pass 24 0.4204 0.3603 85.7 Pass 25 0.4702 0.4025 85.6 Pass 26 0.5173 0.4333 83.8 Pass 27 0.5334 0.4526 84.8 Pass 28 0.6163 0.5246 85.1 Pass 29 0.6328 0.5460 86.3 Pass 30 0.5711 0.4869 85.3 Pass 31 0.5738 0.4970 86.6 Pass Weston Heights North Technical Information Report Nov1 0.6405 0.5492 85.7 Pass 2 0.8058 0.6793 84.3 Pass 3 0.9158 0.7772 84.9 Pass 4 0.8231 0.7020 85.3 Pass 5 0.9898 0.8357 84.4 Pass 6 1.0581 0.8986 84.9 Pass 7 0.8889 0.7509 84.5 Pass 8 0.9673 0.8136 84.1 Pass 9 1.0939 0.9263 84.7 Pass 10 1.3168 1.1109 84.4 Pass 11 1.4622 1.2417 84.9 Pass 12 1.4100 1.1882 84.3 Pass 13 1.5101 1.2790 84.7 Pass 14 1.3152 1.1239 85.4 Pass 15 1.2776 1.0824 84.7 Pass 16 1.3205 1.1257 85.2 Pass 17 1.4056 1.2177 86.6 Pass 18 1.7417 1.4815 85.1 Pass 19 2.0339 1.7578 86.4 Pass 20 1.9295 1.6816 87.2 Pass 21 1.7180 1.4922 86.9 Pass 22 1.7945 1.5357 85.6 Pass 23 2.5226 2.1962 87.1 Pass 24 2.6104 2.2722 87.0 Pass 25 2.3242 2.0369 87.6 Pass 26 2.0776 1.8206 87.6 Pass 27 1.7419 1.5267 87.6 Pass 28 1.7953 1.5686 87.4 Pass 29 2.0188 1.7591 87.1 Pass 30 1.9199 1.6828 87.6 Pass Dec1 2.0203 1.7634 87.3 Pass 2 2.5459 2.2305 87.6 Pass 3 2.3943 2.1200 88.5 Pass 4 2.1073 1.8429 87.5 Pass 5 2.1022 1.8510 88.0 Pass 6 1.8904 1.6683 88.2 Pass 7 1.8446 1.6237 88.0 Pass 8 1.9075 1.6707 87.6 Pass 9 2.1216 1.8525 87.3 Pass 10 2.1856 1.9187 87.8 Pass 11 2.2916 2.0160 88.0 Pass 12 2.3069 2.0331 88.1 Pass 13 2.3732 2.0932 88.2 Pass 14 2.7803 2.4522 88.2 Pass 15 2.5205 2.2265 88.3 Pass 16 2.2674 2.0086 88.6 Pass 17 2.0617 1.8245 88.5 Pass 18 1.9133 1.6893 88.3 Pass 19 2.2016 1.9344 87.9 Pass 20 2.2677 2.0041 88.4 Pass 21 2.1182 1.8734 88.4 Pass 22 2.1436 1.8929 88.3 Pass 23 2.0837 1.8461 88.6 Pass 24 1.9965 1.7622 88.3 Pass 25 2.3660 2.0851 88.1 Pass 26 2.6857 2.3839 88.8 Pass 27 2.2256 1.9880 89.3 Pass Weston Heights North Technical Information Report 28 2.1717 1.9117 88.0 Pass 29 2.7195 2.4127 88.7 Pass 30 2.2713 2.0296 89.4 Pass 31 2.1998 1.9530 88.8 Pass ___________________________________________________________________ LID Report LID Technique Used for Total Volumn Volumn Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volumn Volumn Volumn Water Quality Treatment Facility (ac-ft) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit __________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. 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Weston Heights North Technical Information Report Weston Heights North Technical Information Report SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Weston Heights North Technical Information Report Conveyance System Analysis and Design The Weston Heights North project proposes a new conveyance system along the frontage of NE 7th Pl, a new gravel trench and drain pipe to an existing catch basin at the intersection of Nile Ave and NE 7th Pl, and a connection from the existing french drain at the north end of lot 1 to an existing catch basin in NE 7th Pl. As the gravel trench and french drain will be contributory to an existing conveyance line, analysis will be performed to ensure capacity from these areas and the additional area routed out of the Olympus Villa Pond. Weston Heights North Lots 2 and 3 will tie roof drains into a proposed CB Type 1, which ties into the existing conveyance system contributing to the Olympus Villa Pond. Analysis will also be completed for the system along Nile Ave, designed as part of the Weston Heights project. This analysis was completed to ensure that the concrete inlet and associated storm drain would have capacity to handle the additional area sent to CB5A with the removal of the upstream inlet. The KCSWDM requires that the conveyance flows tributary to each catch basin be calculated to show that the 25-year peak design flows are 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, using StormShed3G, for the proposed layouts and the existing systems being analyzed for capacity are provided in Appendix 5A. For simplicity, 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 isopluvial map is provided in Appendix 5B. The 100-yr flow from the Olympus Villa facility was routed through the downstream system as a fixed flow rate obtained from the KCRTS analysis of the Olympus Villa Pond. Weston Heights North Technical Information Report APPENDIX 5A CONVEYANCE CALCULATIONS PRIVATE ROAD CTRACT ATRACT CTRACT BBASIN #4BASIN #10BASIN #8BASIN #5BASIN #17BASIN #11VAULTBASINBASIN #5BASIN#5ABASIN #12BASIN #13BASIN #5BASIN #3BASIN #5WH-BASIN#8BASIN #5BASIN #1DateProject No.DrawnDesignSheet:JDAJDA7/8/16349-007-15DEVELOPEDCONVEYANCEWESTON HEIGHTS NORTHNNAMEBASINAREAIMERVIOUSAREALAWNAREATOTALWESTON HEIGHTS NORTH BASIN AREASNAMEBASINAREAIMERVIOUSAREALAWNAREATOTALEXISTING OFFSITE DEVELOPMENT BASIN AREAS Weston Heights North Technical Information Report Weston Heights North Layout WN1 Weston Heights North Technical Information Report Layout Report: LayoutWN1 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: EX-P1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐CB2 UpNode EX‐CB1 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 24.37 ft Slope 1.27% Up Invert 515.40 ft Dn Invert 515.09 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 North Technical Information Report Record Id: EX-P2 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐WHCB7 UpNode EX‐CB2 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 60.80 ft Slope 2.02% Up Invert 515.09 ft Dn Invert 513.86 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: EX-P3 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐OVP_IN UpNode EX‐WHCB7 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 519.44 ft Slope 0.63% Up Invert 513.86 ft Dn Invert 510.5699 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover Weston Heights North Technical Information Report 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: WN-P1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐WHCB7 UpNode WN‐CB1 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 24.00 ft Slope 0.50% Up Invert 514.90 ft Dn Invert 514.78 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: WN-P2 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode WN‐CB1 UpNode WN‐CB2 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 112.00 ft Slope 1.00% Weston Heights North Technical Information Report Up Invert 516.02 ft Dn Invert 514.90 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: WN-P3 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode WN‐CB2 UpNode WN‐CB3 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 200.00 ft Slope 2.39% Up Invert 520.79 ft Dn Invert 516.02 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 North Technical Information Report Node Records Record Id: EX-CB1 Descrip: TYPE 1 Increment 0.10 ft Start El. 515.40 ft Max El. 518.35 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: EX-CB2 Descrip: TYPE 1 Increment 0.10 ft Start El. 515.09 ft Max El. 518.39 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: EX-OVP_IN Descrip: OV POND INLET Increment 0.10 ft Start El. 510.57 ft Max El. 517.03 ft Void Ratio 100.00 Dummy Type Node Weston Heights North Technical Information Report Record Id: EX-WHCB7 Descrip: TYPE 1 Increment 0.10 ft Start El. 513.86 ft Max El. 517.91 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: WN-CB1 Descrip: TYPE 1 Increment 0.10 ft Start El. 514.90 ft Max El. 517.90 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: WN-CB2 Descrip: TYPE 1 Increment 0.10 ft Start El. 516.02 ft Max El. 519.60 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 North Technical Information Report Record Id: WN-CB3 Descrip: TYPE 1 Increment 0.10 ft Start El. 520.79 ft Max El. 523.89 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 North Technical Information Report Contributing Drainage Areas 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 0.01 ac DCIA 0.06 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 0.03 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 0.04 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 Weston Heights North Technical Information Report Record Id: BASIN-10 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 0.04 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 0.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn LAWN/LANDSCAPE 0.15 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet TC MIN = 5 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 0.15 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 Weston Heights North Technical Information Report 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 0.03 ac DCIA 0.22 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 0.23 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 Weston Heights North Technical Information Report 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 0.01 ac DCIA 0.23 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 0.73 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 0.73 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI ‐ 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 Weston Heights North Technical Information Report 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 0.01 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 0.11 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 Weston Heights North Technical Information Report Record Id: BASIN-4 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 0.01 ac DCIA 0.07 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 0.03 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 0.07 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: Engenious Systems, Inc. Weston Heights North Technical Information Report 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 WN‐P3 0.12 0.1209 5.9768 0.0202 0.0985 0.0985 12 in Diam 3.0242 7.6098 0.00 BASIN‐13 WN‐P2 0.37 0.373 3.8701 0.0964 0.2098 0.2098 12 in Diam 3.1156 4.9276 0.00 BASIN‐11 WN‐P1 0.47 0.4676 2.7366 0.1709 0.2791 0.2791 12 in Diam 2.6088 3.4843 0.00 BASIN‐4 EX‐P1 0.07 0.0636 4.3614 0.0146 0.0845 0.0845 12 in Diam 1.9915 5.5531 0.00 BASIN‐08 EX‐P2 0.37 0.3299 5.5004 0.06 0.1661 0.1661 12 in Diam 3.8544 7.0034 0.00 BASIN‐10 EX‐P3 2.30 2.0935 3.0801 0.6797 0.6049 0.6049 12 in Diam 4.2137 3.9217 0.00 BASIN‐12 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 511.1885 No approach losses at node WN‐CB1 because inverts and/or crowns are offset. EX‐WHCB7 EX‐OVP_IN 514.7923 ‐‐‐‐‐‐ 0.0003 0.0459 514.8386 517.9100 WN‐CB1 EX‐WHCB7 515.2849 ‐‐‐‐‐‐ 0.2006 ‐‐‐‐‐‐ 515.4855 517.9000 WN‐CB2 WN‐CB1 516.3584 ‐‐‐‐‐‐ 0.0009 ‐‐‐‐‐‐ 516.3592 519.6000 WN‐CB3 WN‐CB2 520.9692 ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ 520.9692 523.8900 EX‐CB2 EX‐WHCB7 515.4016 ‐‐‐‐‐‐ 0.0877 ‐‐‐‐‐‐ 515.4893 518.3900 EX‐CB1 EX‐CB2 515.5311 ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ 515.5311 518.3500 Weston Heights North Technical Information Report Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs)TW Depth (ft) Dc (ft)Dn (ft)Comment EX‐P3 0.9323 0.9323 2.09 0.6186 0.6186 0.6049 SuperCrit flow, Inlet end controls WN‐P1 0.3849 0.3849 0.47 0.2833 0.2833 0.2791 SuperCrit flow, Inlet end controls WN‐P2 0.3384 0.3384 0.37 0.5855 0.2522 0.2098 SuperCrit flow, Inlet end controls WN‐P3 0.1792 0.1792 0.12 0.3392 0.1390 0.0985 SuperCrit flow, Inlet end controls EX‐P2 0.3116 0.3116 0.33 0.9786 0.2367 0.1661 SuperCrit flow, Inlet end controls EX‐P1 0.1311 0.1311 0.06 0.3993 0.1023 0.0845 SuperCrit flow, Inlet end controls Licensed to: SDA Engineers Weston Heights North Technical Information Report Weston Heights North Layout WN2 Weston Heights North Technical Information Report 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‐VAULTOUT 0.50 1.6351 0.3058 0.3796 12 in Diam 1.8284 2.0819 0.50 P‐03 0.50 2.9853 0.1675 0.2764 12 in Diam 2.8279 3.8011 0.00 WN‐P4 0.09 0.431 0.2088 0.1551 6 in Diam 1.7343 2.195 0.09 WN‐P5 0.09 1.3629 0.066 0.087 6 in Diam 3.929 6.9411 0.00 WN‐P6 0.33 1.3629 0.2421 0.1673 6 in Diam 5.7283 6.9411 0.33 EX‐POUT 0.83 6.3001 0.1317 0.245 12 in Diam 5.5606 8.0215 0.83 EX‐P6 1.16 4.9119 0.2362 0.4125 15 in Diam 3.2842 4.0025 0.00 EX‐WHP2 1.25 3.2156 0.3887 0.5415 15 in Diam 2.4533 2.6203 0.00 EX‐WHP1 1.25 4.7373 0.2639 0.4382 15 in Diam 3.2586 3.8603 0.00 WH‐P2 1.25 6.7032 0.1865 0.2926 12 in Diam 6.5298 8.5348 0.00 WH‐P1 1.85 2.7366 0.676 0.6028 12 in Diam 3.7392 3.4843 0.10 HGL Analysis From Node To Node HG El (ft)App (ft)Bend (ft)Junct Loss (ft)Adjusted HG El (ft)Max El (ft) 505.7028 WH‐CB1 DITCH_OUT 506.5133 0.6621 0.0084 0.1849 506.0446 510.6400 CB3 WH‐CB1 506.1992 ‐‐‐‐‐‐ 0.0661 ‐‐‐‐‐‐ 506.2653 516.0300 VAULT‐OUT CB3 506.3318 ‐‐na‐‐ ‐‐na‐‐ ‐‐na‐‐ 506.3318 513.8000 No approach losses at node EX‐WHCB1 because inverts and/or crowns are offset. WH‐CB2 WH‐CB1 506.6692 ‐‐‐‐‐‐ 0.0088 ‐‐‐‐‐‐ 506.6780 511.0100 EX‐WHCB1 WH‐CB2 509.5283 ‐‐‐‐‐‐ 0.0004 ‐‐‐‐‐‐ 509.5286 513.6500 No approach losses at node EX‐CB6 because inverts and/or crowns are offset. EX‐WHCB2 EX‐WHCB1 510.1236 0.1675 0.2355 0.0106 510.2022 519.6900 WN‐SD_TO_EX‐WHCB2 EX‐WHCB2 515.2903 ‐‐na‐‐ ‐‐na‐‐ ‐‐na‐‐ 515.2903 518.0000 Weston Heights North Technical Information Report WN‐DSGT WN‐SD_TO_EX‐WHCB2 515.7712 ‐‐na‐‐ ‐‐na‐‐ ‐‐na‐‐ 515.7712 518.0000 EX‐CB6 EX‐WHCB2 511.3233 ‐‐‐‐‐‐ 0.6392 0.1334 512.0959 518.5200 EX‐FD EX‐CB6 515.5208 ‐‐na‐‐ ‐‐na‐‐ ‐‐na‐‐ 515.5208 516.6000 OVP_OUT EX‐CB6 512.6181 ‐‐na‐‐ ‐‐na‐‐ ‐‐na‐‐ 512.6181 517.0300 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs)TW Depth (ft)Dc (ft)Dn (ft)Comment WH‐P1 0.8633 0.8633 1.85 0.6028 0.5797 0.6028 Outlet Control M1 Backwater P‐03 0.3992 0.3992 0.50 0.3946 0.2932 0.2764 SuperCrit flow, Inlet end controls P‐VAULTOUT 0.5318 0.5318 0.50 0.4773 0.2932 0.3796 Outlet Control M1 Backwater WH‐P2 0.6592 0.6592 1.25 0.4719 0.4719 0.2926 SuperCrit flow, Inlet end controls EX‐WHP1 0.6083 0.4866 1.25 0.4411 0.4411 0.4382 SuperCrit flow, Inlet end controls EX‐WHP2 0.6536 0.5229 1.25 0.5986 0.4411 0.5415 Outlet Control M1 Backwater WN‐P5 0.1903 0.3807 0.09 0.1480 0.1480 0.0870 SuperCrit flow, Inlet end controls WN‐P4 0.2112 0.4223 0.09 0.1903 0.1480 0.1551 Outlet Control M1 Backwater EX‐P6 0.5833 0.4666 1.16 0.4247 0.4247 0.4125 SuperCrit flow, Inlet end controls WN‐P6 0.4208 0.8416 0.33 0.2912 0.2912 0.1673 SuperCrit flow, Inlet end controls EX‐POUT 0.5181 0.5181 0.83 1.3559 0.3813 0.2450 SuperCrit flow, Inlet end controls Licensed to: SDA Engineers Weston Heights North Technical Information Report Layout Report: LayoutWN2 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 *100 year flow rate for OVP_OUT is .83 *100 year flow rate for Vault_OUT is 0.5 *100 year flow rate for EX‐WH1 is 0.10, see Basin 1 record below *100 year flow rate for WN‐DSGT is 0.09, see Basin 3 record below *100 year flow rate for EX‐FD is .33, see Basin 17 record below Reach Records Record Id: EX-P6 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐WHCB2 UpNode EX‐CB6 Material unspecified Size 15 in Diam Ent Losses Groove End w/Headwall Length 119.74 ft Slope 0.49% Up Invert 510.74 ft Dn Invert 510.15 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover Weston Heights North Technical Information Report 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: EX-POUT Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐CB6 UpNode OVP_OUT Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 51.36 ft Slope 2.65% Up Invert 512.10 ft Dn Invert 510.74 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: EX-WHP1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB2 UpNode EX‐WHCB1 Material unspecified Size 15 in Diam Ent Losses Groove End w/Headwall Length 147.00 ft Slope 0.46% Weston Heights North Technical Information Report Up Invert 508.92 ft Dn Invert 508.25 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: EX-WHP2 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐WHCB1 UpNode EX‐WHCB2 Material unspecified Size 15 in Diam Ent Losses Groove End w/Headwall Length 258.34 ft Slope 0.21% Up Invert 509.47 ft Dn Invert 508.93 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-03 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB1 UpNode CB3 Weston Heights North Technical Information Report 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‐OUT Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 8.00 ft Slope 0.15% Up Invert 505.80 ft Dn Invert 505.788 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 North Technical Information Report Record Id: WH-P1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode DITCH_OUT UpNode WH‐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: WH-P2 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB1 UpNode WH‐CB2 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 12.00 ft Slope 3.00% Up Invert 506.01 ft Dn Invert 505.65 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover Weston Heights North Technical Information Report 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: WN-P4 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode WN‐SD_TO_EX‐WHCB2 UpNode WN‐DSGT Material unspecified Size 6 in Diam Ent Losses Groove End w/Headwall Length 68.00 ft Slope 0.69% Up Invert 515.56 ft Dn Invert 515.09 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: WN-P5 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐WHCB2 UpNode WN‐SD_TO_EX‐WHCB2 Material unspecified Size 6 in Diam Ent Losses Groove End w/Headwall Length 34.00 ft Slope 0.50% Weston Heights North Technical Information Report Up Invert 515.09 ft Dn Invert 514.92 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: WN-P6 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX‐CB6 UpNode EX‐FD Material unspecified Size 6 in Diam Ent Losses Groove End w/Headwall Length 32.00 ft Slope 1.09% Up Invert 515.10 ft Dn Invert 514.75 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 North Technical Information Report Node Records 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_OUT Descrip: TYPE 1 Increment 0.10 ft Start El. 505.10 ft Max El. 507.10 ft Void Ratio 100.00 Dummy Type Node Record Id: EX-CB6 Descrip: Type 2 Increment 0.10 ft Start El. 510.74 ft Max El. 518.52 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 2‐48 Channelization No Special Shape Catch 0.00 ft Bottom Area 12.5664 sf MH/CB Type Node Weston Heights North Technical Information Report Record Id: EX-FD Descrip: Lot 1 Ex French Drain Increment 0.10 ft Start El. 515.10 ft Max El. 516.60 ft Void Ratio 100.00 Dummy Type Node Record Id: EX-WHCB1 Descrip: Type 1 Increment 0.10 ft Start El. 508.93 ft Max El. 513.65 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node Record Id: EX-WHCB2 Descrip: Type 2 Increment 0.10 ft Start El. 509.47 ft Max El. 519.69 ft Void Ratio 100.00 Condition Existing Structure Type CB‐TYPE 2‐48 Channelization No Special Shape Catch 0.00 ft Bottom Area 12.5664 sf MH/CB Type Node Weston Heights North Technical Information Report Record Id: OVP_OUT Descrip: OV Pond Outlet Increment 0.10 ft Start El. 512.10 ft Max El. 517.03 ft Void Ratio 100.00 Dummy Type Node Record Id: VAULT-OUT Descrip: 100‐YR FLOW FROM VAULT Increment 0.10 ft Start El. 505.80 ft Max El. 513.80 ft Void Ratio 100.00 Dummy Type Node Record Id: WH-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 North Technical Information Report Record Id: WH-CB2 Descrip: TYPE 1 Increment 0.10 ft Start El. 506.01 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: WN-DSGT Descrip: storm drain into ex wh cb2 Increment 0.10 ft Start El. 515.56 ft Max El. 518.45 ft Void Ratio 100.00 Dummy Type Node Record Id: WN-SD_TO_EX-WHCB2 Descrip: storm drain into ex wh cb2 Increment 0.10 ft Start El. 515.09 ft Max El. 519.97 ft Void Ratio 100.00 Dummy Type Node Licensed to: SDA Engineers Weston Heights North Technical Information Report 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-VAULTOUT 0.50 1.6351 0.3058 0.3796 12 in Diam 1.8284 2.0819 0.50 P-03 0.50 2.9853 0.1675 0.2764 12 in Diam 2.8279 3.8011 0.00 WN-P4 0.09 0.5067 0.1776 0.1425 6 in Diam 1.9508 2.5808 0.09 WN-P5 0.09 0.431 0.2088 0.1551 6 in Diam 1.7343 2.195 0.00 WN-P6 0.33 0.6363 0.5186 0.2556 6 in Diam 3.2683 3.2408 0.33 EX-POUT 0.83 6.3001 0.1317 0.245 12 in Diam 5.5606 8.0215 0.83 EX-P6 1.16 4.9119 0.2362 0.4125 15 in Diam 3.2842 4.0025 0.00 EX-WHP2 1.25 3.2156 0.3887 0.5415 15 in Diam 2.4533 2.6203 0.00 EX-WHP1 1.25 4.7373 0.2639 0.4382 15 in Diam 3.2586 3.8603 0.00 WH-P2 1.25 6.7032 0.1865 0.2926 12 in Diam 6.5298 8.5348 0.00 WH-P1 1.85 2.7366 0.676 0.6028 12 in Diam 3.7392 3.4843 0.10 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 505.7028 WH-CB1 DITCH_OUT 506.5133 0.6621 0.0062 0.1849 506.0424 510.6400 CB3 WH-CB1 506.1992 ------ 0.0661 ------ 506.2653 516.0300 VAULT-OUT CB3 506.3318 --na-- --na-- --na-- 506.3318 513.8000 No approach losses at node EX-WHCB1 because inverts and/or crowns are offset. WH-CB2 WH-CB1 506.6692 ------ 0.0075 ------ 506.6767 511.0100 EX-WHCB1 WH-CB2 509.5283 ------ 0.0006 ------ 509.5288 513.6500 No approach losses at node EX-CB6 because inverts and/or crowns are offset. EX-WHCB2 EX-WHCB1 510.1236 0.1675 0.2343 0.0106 510.2011 519.6900 WN-SD_TO_EX- WHCB2 EX-WHCB2 515.3012 --na-- --na-- --na-- 515.3012 519.9700 WN-DSGT WN-SD_TO_EX- WHCB2 515.7611 --na-- --na-- --na-- 515.7611 518.4500 EX-CB6 EX-WHCB2 511.3233 ------ 0.6393 0.1334 512.0960 518.5200 EX-FD EX-CB6 515.5306 --na-- --na-- --na-- 515.5306 516.6000 OVP_OUT EX-CB6 512.6181 --na-- --na-- --na-- 512.6181 517.0300 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment WH-P1 0.8633 0.8633 1.85 0.6028 0.5797 0.6028 Outlet Control M1 Backwater P-03 0.3992 0.3992 0.50 0.3924 0.2932 0.2764 SuperCrit flow, Inlet end controls P-VAULTOUT 0.5318 0.5318 0.50 0.4773 0.2932 0.3796 Outlet Control M1 Backwater WH-P2 0.6592 0.6592 1.25 0.4719 0.4719 0.2926 SuperCrit flow, Inlet end controls EX-WHP1 0.6083 0.4866 1.25 0.4411 0.4411 0.4382 SuperCrit flow, Inlet end controls EX-WHP2 0.6536 0.5229 1.25 0.5988 0.4411 0.5415 Outlet Control M1 Backwater Weston Heights North Technical Information Report WN-P5 0.2112 0.4223 0.09 0.1551 0.1480 0.1551 Outlet Control M2 Backwater WN-P4 0.2011 0.4022 0.09 0.2112 0.1480 0.1425 SuperCrit flow, Inlet end controls EX-P6 0.5833 0.4666 1.16 0.4247 0.4247 0.4125 SuperCrit flow, Inlet end controls WN-P6 0.4306 0.8611 0.33 0.2912 0.2912 0.2556 SuperCrit flow, Inlet end controls EX-POUT 0.5181 0.5181 0.83 1.3560 0.3813 0.2450 SuperCrit flow, Inlet end controls Licensed to: Engenious Systems, Inc. Weston Heights North Technical Information Report Weston Heights Layout WN3 Weston Heights North Technical Information Report Layout Report: LayoutWN3 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: WH-P4 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐VAULT IN UpNode WH‐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 Record Id: WH-P5 Section Shape: Circular Weston Heights North Technical Information Report Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB4 UpNode WH‐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: WH--P5A Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB5 UpNode WH‐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 North Technical Information Report Record Id: WH-P7 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB4 UpNode WH‐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: WH-P8 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.011 Routing Method: Travel Time Shift Contributing Hyd DnNode WH‐CB7 UpNode WH‐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 Weston Heights North Technical Information Report 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: WH-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: WH-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 Record Id: WH-CB5A Descrip: CONCRETE INLET Increment 0.10 ft Start El. 513.21 ft Max El. 515.46 ft Weston Heights North Technical Information Report 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: WH-CB7 Descrip: TYPE 1 Increment 0.10 ft Start El. 513.10 ft Max El. 518.08 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: WH-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 Weston Heights North Technical Information Report Record Id: WH-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 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 0.22 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 Weston Heights North Technical Information Report 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 0.04 ac DCIA 0.16 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 0.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Land 0.04 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet TC MIN = 5 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 0.17 ac 98.00 Weston Heights North Technical Information Report 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 0.04 ac DCIA 0.16 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 0.00 min DC TC 5.00 min Pervious CN Calc Description SubArea Sub cn Landscape/Land 0.04 ac 86.00 Pervious Composited CN (AMC 2) 86.00 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet TC MIN = 5 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 0.17 ac 98.00 Weston Heights North Technical Information Report 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: WH-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 0.01 ac DCIA 0.06 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 0.23 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 0.49 ac 98.00 Weston Heights North Technical Information Report 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 North Technical Information Report 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 WH‐‐ P5A 0.21 0.2051 7.3126 0.028 0.1153 0.1153 12 in Diam 4.0749 9.3107 0.00 BASIN‐05A WH‐P5 1.01 0.967 7.052 0.1371 0.2501 0.2501 12 in Diam 6.2941 8.9789 0.00 BASIN‐05 WH‐P8 0.72 0.6765 7.1111 0.0951 0.2084 0.2084 12 in Diam 5.7044 9.0542 0.00 WH‐BASIN 08 WH‐P7 0.72 0.6765 7.8191 0.0865 0.1987 0.1987 12 in Diam 6.1057 9.9556 0.00 WH‐P4 1.73 1.6436 15.7574 0.1043 0.2175 0.2175 12 in Diam 13.0367 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) 505.0448 WH‐CB4 WH‐VAULT IN 511.2273 ‐‐‐‐‐‐ 0.0531 0.2655 511.5459 513.4900 WH‐CB5 WH‐CB4 513.1788 ‐‐‐‐‐‐ 0.3432 ‐‐‐‐‐‐ 513.5220 516.4500 WH‐CB5A WH‐CB5 513.8948 ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ 513.8948 515.4600 WH‐CB7 WH‐CB4 513.5568 ‐‐‐‐‐‐ 0.5641 ‐‐‐‐‐‐ 514.1209 518.0800 WH‐CB8 WH‐CB7 516.1712 ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ 516.1712 518.7100 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs)TW Depth (ft) Dc (ft)Dn (ft)Comment WH‐P4 0.7373 0.7373 1.64 0.5448 0.5448 0.2175 SuperCrit flow, Inlet end controls WH‐P5 0.5688 0.5688 0.97 1.0559 0.4128 0.2501 SuperCrit flow, Inlet end controls WH‐‐P5A 0.6848 0.6848 0.21 0.9120 0.1858 0.1153 Outlet Control M1 Backwater WH‐P7 0.4568 0.4568 0.68 1.0559 0.3429 0.1987 SuperCrit flow, Inlet end controls WH‐P8 0.4612 0.4612 0.68 1.0209 0.3429 0.2084 SuperCrit flow, Inlet end controls Weston Heights North Technical Information Report APPENDIX 5B ISOPLUVIAL MAP – 100-YR, 24-HR PRECIPITATION Weston Heights North Technical Information Report SECTION 6 SPECIAL REPORTS AND STUDIES Weston Heights North Technical Information Report Special Reports and Studies A geotechnical report was prepared by The Riley Group, Inc. for the project on January 29th, 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 North Technical Information Report APPENDIX 6A GEOTECHNICAL REPORT Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 ♦ Fax 425.415.0311 www.riley-group.com GEOTECHNICAL ENGINEERING REPORT PREPARED BY: THE RILEY GROUP, INC. 17522 BOTHELL WAY NORTHEAST BOTHELL, WASHINGTON 98011 PREPARED FOR: WESTON HEIGHTS, LLC 15 LAKE BELLEVUE DRIVE, SUITE 102 BELLEVUE, WASHINGTON 98005 RGI PROJECT NO. 2016-009 WESTON NORTH 702 NILE AVENUE NORTHEAST RENTON, WASHINGTON JANUARY 29, 2016 Geotechnical Engineering Report i January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................................... 1 2.0 PROJECT DESCRIPTION ............................................................................................................... 1 3.0 FIELD EXPLORATION AND LABORATORY TESTING .......................................................... 1 3.1 FIELD EXPLORATION ................................................................................................................................... 1 3.2 LABORATORY TESTING ................................................................................................................................ 2 4.0 SITE CONDITIONS ........................................................................................................................... 2 4.1 SURFACE .................................................................................................................................................. 2 4.2 GEOLOGY ................................................................................................................................................. 2 4.3 SOILS ....................................................................................................................................................... 3 4.4 GROUNDWATER ........................................................................................................................................ 3 4.5 SEISMIC CONSIDERATIONS ........................................................................................................................... 3 4.6 GEOLOGIC HAZARD AREAS .......................................................................................................................... 4 5.0 DISCUSSION AND RECOMMENDATIONS ................................................................................. 4 5.1 GEOTECHNICAL CONSIDERATIONS ................................................................................................................. 4 5.2 EARTHWORK ............................................................................................................................................. 4 5.2.1 Erosion and Sediment Control ..................................................................................................... 4 5.2.2 Stripping ....................................................................................................................................... 5 5.2.3 Excavations................................................................................................................................... 6 5.2.4 Site Preparation ........................................................................................................................... 6 5.2.5 Structural Fill ................................................................................................................................ 7 5.2.6 Cut and Fill Slopes ........................................................................................................................ 8 5.2.7 Wet Weather Construction Considerations ................................................................................. 8 5.3 FOUNDATIONS .......................................................................................................................................... 9 5.4 RETAINING WALLS ................................................................................................................................... 10 5.5 SLAB-ON-GRADE CONSTRUCTION ............................................................................................................... 10 5.6 DRAINAGE .............................................................................................................................................. 11 5.6.1 Surface ....................................................................................................................................... 11 5.6.2 Subsurface .................................................................................................................................. 11 5.6.3 Infiltration .................................................................................................................................. 11 5.7 UTILITIES ................................................................................................................................................ 11 5.8 PAVEMENTS ............................................................................................................................................ 11 6.0 ADDITIONAL SERVICES .............................................................................................................. 12 7.0 LIMITATIONS ................................................................................................................................. 12 LIST OF FIGURES AND APPENDICES Figure 1 ..................................................................................................................... Site Vicinity Map Figure 2 ............................................................................................... Geotechnical Exploration Plan Figure 3 ...................................................................................Typical Retaining Wall Drainage Detail Figure 4 ....................................................................................................Typical Footing Drain Detail Appendix A .......................................................................... Field Exploration and Laboratory Testing Geotechnical Engineering Report ii January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 Executive Summary This Executive Summary should be used in conjunction with the entire Geotechnical Engineering Report (GER) for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and the GER must be read in its entirety for a comprehensive understanding of the items contained herein. Section 7.0 should be read for an understanding of limitations. RGI’s geotechnical scope of work included the advancement of 3 hand augers to a maximum depth of 3.5 feet below existing site grades. Based on the information obtained from our subsurface exploration, the site is suitable for development of the proposed project. The following geotechnical considerations were identified: Soil Conditions: The soils encountered during field exploration includes soft to medium stiff silt with some sand and medium dense silty sand with some gravel . Groundwater: Light groundwater seepage was encountered between depths of 8 to 18 inches bgs during our subsurface exploration. Foundations: Foundations for the proposed building may be supported on conventional spread footings bearing on medium dense to dense native soil or structural fill. Slab-on-grade: Slab-on-grade floors and slabs for the proposed building can be supported on medium dense to dense native soil or structural fill. Pavements: The following pavement sections are recommended: For heavy truck traffic areas: 3 inches of Hot Mix Asphalt (HMA) over 6 inches of crushed rock base (CRB) For general parking areas: 2 inches of HMA over 4 inches of CRB Geotechnical Engineering Report 1 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 1.0 Introduction This Geotechnical Engineering Report (GER) presents the results of the geotechnical engineering services provided for the Weston North short plat in Renton, Washington. The purpose of this evaluation is to assess subsurface conditions and provide geotechnical recommendations for the construction of single family residences. Our scope of services included field explorations, laboratory testing, engineering analyses, and preparation of this GER. The recommendations in the following sections of this GER are based upon our current understanding of the proposed site development as outlined below. If actual features vary or changes are made, RGI should review them in order to modify our recommendations as required. In addition, RGI requests to review the site grading plan, final design drawings and specifications when available to verify that our project understanding is correct and that our recommendations have been properly interpreted and incorporated into the project design and construction. 2.0 Project description The project site is located at 702 Nile Avenue Northeast in Renton, Washington. The approximate location of the site is shown on Figure 1. The site is currently occupied by a single family residence with a shop to the west and a grass field to the east of the residence. RGI understands that the parcel will be subdivided into six lots with construction of five new single family residences. The existing residence and shop will remain on Lot 1. Our understanding of the project is based on conversations with the client, and a site plan that was forwarded to us by SDA dated October 24, 2015. At the time of preparing this GER, building plans were not available for our review. Based on our experience with similar construction, RGI anticipates that the proposed building will be supported on perimeter walls with bearing loads of two to four kips per linear foot, and a series of columns with a maximum load up to 20 kips. Slab-on-grade floor loading of 250 pounds per square foot (psf) are expected. 3.0 Field Exploration and Laboratory Testing 3.1 FIELD EXPLORATION On January 22, 2016, RGI excavated three hand augers. The approximate exploration locations are shown on Figure 2. Field logs of each exploration were prepared by the geologist that completed the excavation. These logs included visual classifications of the materials encountered during excavation. The hand augers logs included in Appendix A represent an interpretation of Geotechnical Engineering Report 2 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 the field logs and include modifications based on laboratory observation and analysis of the samples. 3.2 LABORATORY TESTING During the field exploration, a representative portion of each recovered sample was sealed in containers and transported to our laboratory for further visual and laboratory examination. Selected samples retrieved from the hand augers were tested for moisture content and grain size analysis, to aid in soil classification and provide input for the recommendations provided in this GER. The results and descriptions of the laboratory tests are enclosed in Appendix A. 4.0 Site Conditions 4.1 SURFACE The subject site is a rectangular-shaped parcel of land approximately 2.3 acres in size. The site is bound to the north by Northeast 7th Place, to the east by residential property and a private road, to the south by a wetland and residential properties, and to the west by Nile Avenue Northeast. The existing site houses a shop and a single family residence that are located within the western section of the site. A handful of trees are located along the western portion of the south property line with a cluster of 20 foot tall bamboo stalks to the northeast of the house. The remaining area (central to eastern portion of the site) is occupied by a large grassy field, where the proposed new single family residences would be constructed. The site is relatively flat with an overall elevation difference of approximately 6 feet, increasing in elevation towards the east. 4.2 GEOLOGY Review of the Geologic Map of the Renton Quadrangle King County, Washington, by D.R. Mullineaux, (1965) indicates that the soil in the project vicinity is mapped as Ground moraine deposits (Qgt), which is mostly thin ablation till over lodgment till, deposited by Puget glacial lobe. Lodgment till generally compact, coherent, unsorted mixture of sand, silt, clay and gravel: commonly termed hardpan. Ablation till similar, but much less compact and coherent. Highly variable in thickness and in relative proportion of lodgment to ablation till; lodgment till generally 5 to 30 feet thick, ablation till 2 to 10 feet. North of Cedar River, till is mostly sand, is relatively friable and locally less than 5 feet thick. Between Renton and Lake Youngs, lodgment till locally is thin, but ablation till is relatively thick and grades to stratified drift. Moderately drumlinized, forms undulating, locally irregular surface characterized by southeast-ward-trending hills and swales, commonly overlain by thin sand, clay or peat. Surface drainage is locally poor. Lodgment till is nearly impermeable and relatively difficult to excavate, but relatively stable in cut slopes. These descriptions are generally similar to the findings in our field explorations. Geotechnical Engineering Report 3 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 4.3 SOILS The soils encountered during field exploration include silt with some sand to silty sand with some gravel. Hand auger locations HA-2 and HA-3 encountered dense to very dense soils that contained large gravels and cobbles that prevented further advancement in depth. More detailed descriptions of the subsurface conditions encountered are presented in the hand auger logs included in Appendix A. Sieve analysis was performed on two selected soil samples. Grain size distribution curves are included in Appendix A. 4.4 GROUNDWATER Light groundwater seepage was encountered between 8 to 18 inches bgs during our subsurface exploration. The groundwater appears to be perched over the top of a medium stiff SILT layer. Surface water was also observed in the grassy field during the exploration. It should be recognized that fluctuations of the groundwater table will occur due to seasonal variations in the amount of rainfall, runoff, and other factors not evident at the time the explorations were performed. In addition, perched water can develop within seams and layers contained in fill soils or higher permeability soils overlying less permeable soils following periods of heavy or prolonged precipitation. Therefore, groundwater levels during construction or at other times in the future may be higher or lower than the levels indicated on the logs. Groundwater level fluctuations should be considered when developing the design and construction plans for the project. 4.5 SEISMIC CONSIDERATIONS Based on the 2012 International Building Code (IBC), RGI recommends the follow seismic parameters for design. Table 1 2012 IBC Parameter Value Site Soil Class1 C2 Site Latitude 47.494016o N Site Longitude 122.141161o W Short Period Spectral Response Acceleration, SS (g) 1.387 1-Second Period Spectral Response Acceleration, S1 (g) 0.521 Adjusted Short Period Spectral Response Acceleration, SMS (g) 1.387 Adjusted 1-Second Period Spectral Response Acceleration, SM1 (g) 0.677 1. Note: In general accordance with Chapter 20 of ASCE 7. The Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. Geotechnical Engineering Report 4 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 2. Note: The 2012 IBC and ASCE 7 require a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope of our services does not include the required 100 foot soil profile determination. Hand augers extended to a maximum depth of 3.5 feet, and this seismic site class definition considers that very dense soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations from a seismic event. Liquefaction mainly affects geologically recent deposits of fine-grained sands that are below the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil grains and eliminates this intergranular friction, thus reducing or eliminating the soil’s strength. RGI reviewed the results of the field and laboratory testing and assessed the potential for liquefaction of the site’s soil during an earthquake. Since the site is underlain by glacial till, RGI considers that the possibility of liquefaction during an earthquake is minimal. 4.6 GEOLOGIC HAZARD AREAS Regulated geologically hazardous areas include erosion, landslide, earthquake, or other geological hazards. Based on the definitions in the Renton Municipal Code, the site does not contain geologically hazardous areas. There are not mapped coal mine hazards, steep slopes or landslide hazard on the site or in the near vicinity of the site. A wetland is mapped on the parcel to the south of the site and appears to extend slightly into the site. 5.0 Discussion and Recommendations 5.1 GEOTECHNICAL CONSIDERATIONS Based on our study, the site is suitable for the proposed construction from a geotechnical standpoint. Foundations for the proposed building can be supported on conventional spread footings bearing on medium dense to dense native soil or structural fill. Slab-on- grade and pavements can be similarly supported. Detailed recommendations regarding the above issues and other geotechnical design considerations are provided in the following sections. These recommendations should be incorporated into the final design drawings and construction specifications. 5.2 EARTHWORK The earthwork is expected to include installing underground utilities excavating and backfilling the residence foundations and preparing sidewalk, driveway and frontage improvement roadway subgrades. 5.2.1 EROSION AND SEDIMENT CONTROL Potential sources or causes of erosion and sedimentation depend on construction methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type, Geotechnical Engineering Report 5 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 construction sequencing and weather. The impacts on erosion-prone areas can be reduced by implementing an erosion and sedimentation control plan. The plan should be designed in accordance with applicable city and/or county standards. RGI recommends the following erosion control Best Management Practices (BMPs): Scheduling site preparation and grading for the drier summer and early fall months and undertaking activities that expose soil during periods of little or no rainfall Retaining existing vegetation whenever feasible Establishing a quarry spall construction entrance Installing siltation control fencing or anchored straw or coir wattles on the downhill side of work areas Covering soil stockpiles with anchored plastic sheeting Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw if surfaces will be left undisturbed for more than one day during wet weather or one week in dry weather Directing runoff away from exposed soils and slopes Minimizing the length and steepness of slopes with exposed soils and cover excavation surfaces with anchored plastic sheeting (Graded and disturbed slopes should be tracked in place with the equipment running perpendicular to the slope contours so that the track marks provide a texture to help resist erosion and channeling. Some sloughing and raveling of slopes with exposed or disturbed soil should be expected.) Decreasing runoff velocities with check dams, straw bales or coir wattles Confining sediment to the project site Inspecting and maintaining erosion and sediment control measures frequently (The contractor should be aware that inspection and maintenance of erosion control BMPs is critical toward their satisfactory performance. Repair and/or replacement of dysfunctional erosion control elements should be anticipated.) Permanent erosion protection should be provided by reestablishing vegetation using hydroseeding and/or landscape planting. Until the permanent erosion protection is established, site monitoring should be performed by qualified personnel to evaluate the effectiveness of the erosion control measures. Provisions for modifications to the erosion control system based on monitoring observations should be included in the erosion and sedimentation control plan. 5.2.2 STRIPPING Stripping efforts should include removal of pavements, vegetation, organic materials, and deleterious debris from areas slated for building, pavement, and utility construction. The hand augers encountered eight to 14 inches of topsoil and rootmass. Deeper areas of stripping may be required in forested or heavily vegetated areas of the site. Geotechnical Engineering Report 6 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 5.2.3 EXCAVATIONS All temporary cut slopes associated with the site and utility excavations should be adequately inclined to prevent sloughing and collapse. The site soils consist of dense native soils. Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the temporary side slopes should be laid back with a minimum slope inclination of 1.5H:1V (Horizontal:Vertical) where groundwater seepage is encountered and 3/4H:1V in the underlying dense soils. If there is insufficient room to complete the excavations in this manner, or excavations greater than 20 feet in depth are planned, using temporary shoring to support the excavations should be considered. For open cuts at the site, RGI recommends: No traffic, construction equipment, stockpiles or building supplies are allowed at the top of cut slopes within a distance of at least five feet from the top of the cut Exposed soil along the slope is protected from surface erosion using waterproof tarps and/or plastic sheeting Construction activities are scheduled so that the length of time the temporary cut is left open is minimized Surface water is diverted away from the excavation The general condition of slopes should be observed periodically by a geotechnical engineer to confirm adequate stability and erosion control measures In all cases, however, appropriate inclinations will depend on the actual soil and groundwater conditions encountered during earthwork. Ultimately, the site contractor must be responsible for maintaining safe excavation slopes that comply with applicable OSHA or WISHA guidelines. 5.2.4 SITE PREPARATION Once stripping, clearing and other preparing operations are complete, the footings should be excavated into the native soils. Subgrade soils that become disturbed due to elevated moisture conditions should be overexcavated to reveal firm, non-yielding, non-organic soils and backfilled with compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI recommends that the earthwork portion of this project be completed during extended periods of warm and dry weather if possible. If earthwork is completed during the wet season (typically November through May) it will be necessary to take extra precautionary measures to protect subgrade soils. Wet season earthwork will require additional mitigative measures beyond that which would be expected during the drier summer and fall months. Geotechnical Engineering Report 7 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 5.2.5 STRUCTURAL FILL RGI recommends fill below the foundation and floor slab, behind retaining walls, and below pavement and hardscape surfaces be placed in accordance with the following recommendations for structural fill. The suitability of excavated site soils and import soils for compacted structural fill use will depend on the gradation and moisture content of the soil when it is placed. As the amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines cannot be consistently compacted to a dense, non-yielding condition when the moisture content is more than 2 percent above or below optimum. Optimum moisture content is that moisture that results in the greatest compacted dry density with a specified compactive effort. Non-organic site soils are only considered suitable for structural fill provided that their moisture content is within about two percent of the optimum moisture level as determined by ASTM D1557. Excavated site soils may not be suitable for re-use as structural fill depending on the moisture content and weather conditions at the time of construction. If soils are stockpiled for future reuse and wet weather is anticipated, the stockpile should be protected with plastic sheeting that is securely anchored. Even during dry weather, moisture conditioning (such as, windrowing and drying) of site soils to be reused as structural fill may be required. Even during the summer, delays in grading can occur due to excessively high moisture conditions of the soils or due to precipitation. If wet weather occurs, the upper wetted portion of the site soils may need to be scarified and allowed to dry prior to further earthwork, or may need to be wasted from the site. The native soils were over the optimum moisture content during our explorations. The native soils may require moisture conditioning even in the drier summer months. If on- site soils are or become unusable or earthwork will be completed in wet weather, it may become necessary to import clean, granular soils to complete site work that meet the grading requirements listed in Table 2 to be used as structural fill. Table 2 Structural Fill Gradation U.S. Sieve Size Percent Passing 4 inches 100 No. 4 sieve 75 percent No. 200 sieve 5 percent * *Based on minus 3/4 inch fraction. Geotechnical Engineering Report 8 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 Prior to use, an RGI representative should observe and test all materials imported to the site for use as structural fill. Structural fill materials should be placed in uniform loose layers not exceeding 12 inches and compacted as specified in Table 2. The soil’s maximum density and optimum moisture should be determined by ASTM D1557. Table 3 Structural Fill Compaction ASTM D1557 Location Material Type Minimum Compaction Percentage Moisture Content Range Foundations On-site granular or approved imported fill soils: 95 +2 -2 Retaining Wall Backfill On-site granular or approved imported fill soils: 92 +2 -2 Slab-on-grade On-site granular or approved imported fill soils: 95 +2 -2 General Fill (non- structural areas) On-site soils or approved imported fill soils: 90 +3 -2 Pavement – Subgrade and Base Course On-site granular or approved imported fill soils: 95 +2 -2 Placement and compaction of structural fill should be observed by RGI. A representative number of in-place density tests should be performed as the fill is being placed to confirm that the recommended level of compaction is achieved. 5.2.6 CUT AND FILL SLOPES All permanent cut and fill slopes (except interior slopes of detention pond) should be graded with a finished inclination no greater than 2H:1V. The interior slopes of the detention pond must be graded with a slope gradient no steeper than 3H:1V. Upon completion of construction, the slope face should be trackwalked, compacted and vegetated, or provided with other physical means to guard against erosion. Final grades at the top of the slopes must promote surface drainage away from the slope crest. Water must not be allowed to flow in an uncontrolled fashion over the slope face. If it is necessary to direct surface runoff towards the slope, it should be controlled at the top of the slope, piped in a closed conduit installed on the slope face, and taken to an appropriate point of discharge beyond the toe of the slope. All fill placed for slope construction should meet the structural fill requirements as described in Section 5.2.5. 5.2.7 WET WEATHER CONSTRUCTION CONSIDERATIONS RGI recommends that preparation for site grading and construction include procedures intended to drain ponded water, control surface water runoff, and to collect shallow subsurface seepage zones in excavations where encountered. It will not be possible to Geotechnical Engineering Report 9 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 successfully compact the subgrade or utilize on-site soils as structural fill if accumulated water is not drained prior to grading or if drainage is not controlled during construction. Attempting to grade the site without adequate drainage control measures will reduce the amount of on-site soil effectively available for use, increase the amount of select import fill materials required, and ultimately increase the cost of the earthwork phases of the project. Free water should not be allowed to pond on the subgrade soils. RGI anticipates that the use of berms and shallow drainage ditches, with sumps and pumps in utility trenches, will be required for surface water control during wet weather and/or wet site conditions. 5.3 FOUNDATIONS Following site preparation and grading, the proposed residence foundations can be supported on conventional spread footings bearing on medium dense to dense native soil or structural fill. Loose, organic, or other unsuitable soils may be encountered in the proposed building footprint. If unsuitable soils are encountered, they should be overexcavated and backfilled with structural fill. Perimeter foundations exposed to weather should be at a minimum depth of 18 inches below final exterior grades. Interior foundations can be constructed at any convenient depth below the floor slab. Finished grade is defined as the lowest adjacent grade within 5 feet of the foundation for perimeter (or exterior) footings and finished floor level for interior footings. Table 4 Foundation Design Design Parameter Value Allowable Bearing Capacity - Structural Fill Dense native soils 2,500 psf1 4,000 psf Friction Coefficient 0.30 Passive pressure (equivalent fluid pressure) 250 pcf2 Minimum foundation dimensions Columns: 24 inches Walls: 16 inches 1. psf = pounds per square foot 2. pcf = pounds per cubic foot The allowable foundation bearing pressures apply to dead loads plus design live load conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this allowable capacity may be used. At perimeter locations, RGI recommends not including the upper 12 inches of soil in the computation of passive pressures because they can be affected by weather or disturbed by future grading activity. The passive pressure value assumes the foundation will be constructed neat against competent soil or backfilled with Geotechnical Engineering Report 10 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 structural fill as described in Section 5.2.5. The recommended base friction and passive resistance value includes a safety factor of about 1.5. With spread footing foundations designed in accordance with the recommendations in this section, maximum total and differential post-construction settlements of 1 inch and 1/2 inch, respectively, should be expected. 5.4 RETAINING WALLS If retaining walls are needed for the residences, RGI recommends cast-in-place concrete walls be used. The magnitude of earth pressure development on retaining walls will partly depend on the quality of the wall backfill. RGI recommends placing and compacting wall backfill as structural fill. Wall drainage will be needed behind the wall face. A typical retaining wall drainage detail is shown in Figure 3. With wall backfill placed and compacted as recommended, and drainage properly installed, RGI recommends using the values in the following table for design. Table 5 Retaining Wall Design Design Parameter Value Allowable Bearing Capacity - Structural Fill Dense native soils 2,500 psf 4,000 psf Active Earth Pressure (unrestrained walls) 35 pcf At-rest Earth Pressure (restrained walls) 50 pcf For seismic design, an additional uniform load of 7 times the wall height (H) for unrestrained walls and 14H in psf for restrained walls should be applied to the wall surface. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in Section 5.3. 5.5 SLAB-ON-GRADE CONSTRUCTION Once site preparation has been completed as described in Section 5.2, suitable support for slab-on-grade construction should be provided. RGI recommends that the concrete slab be placed on top of medium dense native soil or structural fill. Immediately below the floor slab, RGI recommends placing a four-inch thick capillary break layer of clean, free-draining sand or gravel that has less than five percent passing the U.S. No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. Where moisture by vapor transmission is undesirable, an 8- to 10-millimeter thick plastic membrane should be placed on a 4-inch thick layer of clean gravel. Geotechnical Engineering Report 11 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 For the anticipated floor slab loading, we estimate post-construction floor settlements of 1/4- to 1/2-inch. For thickness design of the slab subjected to point loading from storage racks, RGI recommends using a subgrade modulus (KS) of 150 pounds per square inch per inch of deflection. 5.6 DRAINAGE 5.6.1 SURFACE Final exterior grades should promote free and positive drainage away from the residences. Water must not be allowed to pond or collect adjacent to foundations or within the immediate building area. For non-pavement locations, RGI recommends providing a minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the building perimeter. In paved locations, a minimum gradient of 1 percent should be provided unless provisions are included for collection and disposal of surface water adjacent to the structure. 5.6.2 SUBSURFACE RGI recommends installing perimeter foundation drains. A typical footing drain detail is shown on Figure 4. The foundation drains and roof downspouts should be tightlined separately to an approved discharge facility. Subsurface drains must be laid with a gradient sufficient to promote positive flow to a controlled point of approved discharge. 5.6.3 INFILTRATION Infiltration is not feasible on the site due to the presence of nearly impermeable soils and shallow groundwater conditions. 5.7 UTILITIES Utility pipes should be bedded and backfilled in accordance with American Public Works Association (APWA) specifications. For site utilities located within the right-of-ways, bedding and backfill should be completed in accordance with City of Renton specifications. At a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 5.2.5. Where utilities occur below unimproved areas, the degree of compaction can be reduced to a minimum of 90 percent of the soil’s maximum density as determined by the referenced ASTM D1557. As noted, soils excavated on site may not be suitable for use as backfill material. Imported structural fill meeting the gradation provided in Table 2 may be necessary for trench backfill. 5.8 PAVEMENTS Pavement subgrades should be prepared as described in Section 5.2 and as discussed below. Regardless of the relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. The subgrade should be proofrolled with heavy construction equipment to verify this condition. Geotechnical Engineering Report 12 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 With the pavement subgrade prepared as described above, RGI recommends the following pavement sections for parking and drive areas paved with flexible asphalt concrete surfacing. For heavy truck traffic areas: 3 inches of Hot Mix Asphalt (HMA) over 6 inches of crushed rock base (CRB) For general parking areas: 2 inches of HMA over 4 inches of CRB The asphalt paving materials used should conform to the Washington State Department of Transportation (WSDOT) specifications for HMA and CRB surfacing. Long-term pavement performance will depend on surface drainage. A poorly-drained pavement section will be subject to premature failure as a result of surface water infiltrating into the subgrade soils and reducing their supporting capability. For optimum pavement performance, surface drainage gradients of no less than 2 percent are recommended. Also, some degree of longitudinal and transverse cracking of the pavement surface should be expected over time. Regular maintenance should be planned to seal cracks when they occur. 6.0 Additional Services RGI is available to provide further geotechnical consultation throughout the design phase of the project. RGI should review the final design and specifications in order to verify that earthwork and foundation recommendations have been properly interpreted and incorporated into project design and construction. RGI is also available to provide geotechnical engineering and construction monitoring services during construction. The integrity of the earthwork and construction depends on proper site preparation and procedures. In addition, engineering decisions may arise in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of this scope of work. If these services are desired, please let us know and we will prepare a cost proposal. 7.0 Limitations This GER is the property of RGI, Weston Heights, LLC, and its designated agents. Within the limits of the scope and budget, this GER was prepared in accordance with generally accepted geotechnical engineering practices in the area at the time this GER was issued. This GER is intended for specific application to the Weston North project in Renton, Washington, and for the exclusive use of Weston Heights, LLC and its authorized representatives. No other warranty, expressed or implied, is made. Site safety, excavation support, and dewatering requirements are the responsibility of others. The scope of services for this project does not include either specifically or by implication any environmental or biological (for example, mold, fungi, bacteria) assessment of the Geotechnical Engineering Report 13 January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, we can provide a proposal for these services. The analyses and recommendations presented in this GER are based upon data obtained from the test exploration performed on site. Variations in soil conditions can occur, the nature and extent of which may not become evident until construction. If variations appear evident, RGI should be requested to reevaluate the recommendations in this GER prior to proceeding with construction. It is the client’s responsibility to see that all parties to the project, including the designers, contractors, subcontractors, are made aware of this GER in its entirety. The use of information contained in this GER for bidding purposes should be done at the contractor’s option and risk. USGS, 2014, Mercer Island, Washington USGS, 2014, Renton, Washington 7.5-Minute Quadrangle Approximate Scale: 1"=1000' 0 500 1000 2000 N Site Vicinity Map Figure 1 01/2016 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Weston North RGI Project Number 2016-009 Date Drawn: Address: 702 Nile Avenue Northeast, Renton, Washington 98059 SITE HA-1HA-2HA-301/2016Corporate Office17522 Bothell Way NortheastBothell, Washington 98011Phone: 425.415.0551Fax: 425.415.0311Weston NorthRGI Project Number2016-009Date Drawn:Address: 702 Nile Avenue Northeast, Renton, Washington 98059Geotechnical Exploration PlanFigure 2Approximate Scale: 1"=80'04080160N = HA-1 to HA-3 excavated by RGI, 1/22/16Drawn from Roadway and Drainage Plan by SDA, Civil Engineers Incliniations) 12" Over the Pipe 3" Below the Pipe Perforated Pipe 4" Diameter PVC Compacted Structural Backfill (Native or Import) 12" min. Filter Fabric Material 12" Minimum Wide Free-Draining Gravel Slope to Drain (See Report for Appropriate Excavated Slope 01/2016 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Weston North RGI Project Number 2016-009 Date Drawn: Address: 702 Nile Avenue Northeast, Renton, Washington 98059 Retaining Wall Drainage Detail Figure 3 Not to Scale 3/4" Washed Rock or Pea Gravel 4" Perforated Pipe Building Slab Structural Backfill Compacted Filter Fabric 01/2016 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Weston North RGI Project Number 2016-009 Date Drawn: Address: 702 Nile Avenue Northeast, Renton, Washington 98059 Typical Footing Drain Detail Figure 4 Not to Scale Geotechnical Engineering Report January 29, 2016 Weston North, Renton, Washington RGI Project No. 2016-009 APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING On January 22, 2016, RGI performed field explorations using a hand auger. We explored subsurface soil conditions at the site by excavating three hand augers to a maximum depth of 3.5 feet below existing grade. The hand augers locations are shown on Figure 2. The hand augers locations were approximately determined by measurements from existing property lines and paved roads. A geologist from our office conducted the field exploration and classified the soil conditions encountered, maintained a log of each test exploration, obtained representative soil samples, and observed pertinent site features. All soil samples were visually classified in accordance with the Unified Soil Classification System (USCS). Representative soil samples obtained from the explorations were placed in closed containers and taken to our laboratory for further examination and testing. As a part of the laboratory testing program, the soil samples were classified in our in house laboratory based on visual observation, texture, plasticity, and the limited laboratory testing described below. Moisture Content Determinations Moisture content determinations were performed in accordance with ASTM D2216-10 Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass (ASTM D2216) on representative samples obtained from the exploration in order to aid in identification and correlation of soil types. The moisture content of typical sample was measured and is reported on the hand augers logs. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses was determined using D6913-04(2009) Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis (ASTM D6913) on two of the samples. THE RILEY GROUP, INC. 17522 Bothell Way NE Bothell, WA 98011 PHONE: (425) 415-0551 FAX: (425) 415-0311 GRAIN SIZE ANALYSIS ASTM D421, D422, D1140, D2487, D6913 PROJECT TITLE Weston North SAMPLE ID/TYPE HA-1 S-3 PROJECT NO.2016-009 SAMPLE DEPTH 3.5' TECH/TEST DATE PL 1/22/2106 DATE RECEIVED 1/22/2016 WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture Wt Wet Soil & Tare (gm) (w1)347.8 Weight Of Sample (gm)268.5 Wt Dry Soil & Tare (gm)(w2)268.5 Tare Weight (gm) 8.5 Weight of Tare (gm)(w3)8.5 (W6) Total Dry Weight (gm)260.0 Weight of Water (gm)(w4=w1-w2)79.3 SIEVE ANALYSIS Weight of Dry Soil (gm) (w5=w2-w3)260.0 Cumulative Moisture Content (%) (w4/w5)*100 31 Wt Ret (Wt-Tare) (%Retained)% PASS +Tare {(wt ret/w6)*100}(100-%ret) % COBBLES 0.0 12.0"8.5 0.00 0.00 100.00 cobbles % C GRAVEL 0.0 3.0"8.5 0.00 0.00 100.00 coarse gravel % F GRAVEL 1.3 2.5" coarse gravel % C SAND 2.7 2.0" coarse gravel % M SAND 6.7 1.5"8.5 0.00 0.00 100.00 coarse gravel % F SAND 6.5 1.0" coarse gravel % FINES 82.8 0.75"8.5 0.00 0.00 100.00 fine gravel % TOTAL 100.0 0.50" fine gravel 0.375"8.5 0.00 0.00 100.00 fine gravel D10 (mm)#4 11.8 3.30 1.27 98.73 coarse sand D30 (mm)#10 18.8 10.30 3.96 96.04 medium sand D60 (mm)#20 medium sand Cu #40 36.1 27.60 10.62 89.38 fine sand Cc #60 fine sand #100 47.4 38.90 14.96 85.04 fine sand #200 53.1 44.60 17.15 82.85 fines PAN 268.5 260.00 100.00 0.00 silt/clay DESCRIPTION SILT with some sand USCS ML Prepared For:Reviewed By:KMW Weston Heights, LLC 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000 % P A S S I N G Grain size in millimeters 12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200 THE RILEY GROUP, INC. 17522 Bothell Way NE Bothell, WA 98011 PHONE: (425) 415-0551 FAX: (425) 415-0311 GRAIN SIZE ANALYSIS ASTM D421, D422, D1140, D2487, D6913 PROJECT TITLE Weston North SAMPLE ID/TYPE HA-2 S-2 PROJECT NO.2016-009 SAMPLE DEPTH 2' TECH/TEST DATE PL 1/22/2106 DATE RECEIVED 1/22/2016 WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture Wt Wet Soil & Tare (gm) (w1)322.0 Weight Of Sample (gm)238.0 Wt Dry Soil & Tare (gm)(w2)238.0 Tare Weight (gm) 8.4 Weight of Tare (gm)(w3)8.4 (W6) Total Dry Weight (gm)229.6 Weight of Water (gm)(w4=w1-w2)84.0 SIEVE ANALYSIS Weight of Dry Soil (gm) (w5=w2-w3)229.6 Cumulative Moisture Content (%) (w4/w5)*100 37 Wt Ret (Wt-Tare) (%Retained)% PASS +Tare {(wt ret/w6)*100}(100-%ret) % COBBLES 0.0 12.0"8.4 0.00 0.00 100.00 cobbles % C GRAVEL 0.0 3.0"8.4 0.00 0.00 100.00 coarse gravel % F GRAVEL 15.4 2.5" coarse gravel % C SAND 11.7 2.0" coarse gravel % M SAND 13.9 1.5"8.4 0.00 0.00 100.00 coarse gravel % F SAND 21.6 1.0" coarse gravel % FINES 37.4 0.75"8.4 0.00 0.00 100.00 fine gravel % TOTAL 100.0 0.50" fine gravel 0.375"17.6 9.20 4.01 95.99 fine gravel D10 (mm)#4 43.8 35.40 15.42 84.58 coarse sand D30 (mm)#10 70.7 62.30 27.13 72.87 medium sand D60 (mm)#20 medium sand Cu #40 102.6 94.20 41.03 58.97 fine sand Cc #60 fine sand #100 133.2 124.80 54.36 45.64 fine sand #200 152.1 143.70 62.59 37.41 fines PAN 238.0 229.60 100.00 0.00 silt/clay DESCRIPTION Silty SAND with some gravel USCS SM Prepared For:Reviewed By:KMW Weston Heights, LLC 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.11101001000 % P A S S I N G Grain size in millimeters 12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200 Weston Heights North Technical Information Report APPENDIX 6B OLYMPUS VILLA LUA 10-090 Weston Heights North Technical Information Report APPENDIX 6C OLYMPUS VILLA AS-BUILT PLANS Weston Heights North Technical Information Report SECTION 7 OTHER PERMITS Weston Heights North Technical Information Report Other Permits This project will require the following permits: Right-of-Way Use Permit - City of Renton Construction Stormwater Permit - WA Dept. of Ecology Weston Heights North Technical Information Report SECTION 8 CSWPPP ANALYSIS AND DESIGN Weston Heights North 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 North 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 North 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 North 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 North 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 North 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 North 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 North 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 North 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 North 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 North 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 North Technical Information Report APPENDIX 8A SITE PLAN WITH BMP MEASURES & CALCS TRACT BNILE AVE NENE 7TH PL PASCO AVE NETRACT B NKDSKDSSAMSAM10/4/16349-007-15-1"=40'NW 1/4, SW 1/4 OF SECTION 11, TOWNSHIP 23 N., RANGE 5 E., W.M.WESTON HEIGHTS, LLC15 LAKE BELLEVUE, STE 102BELLEVUE, WA 98005(425)869-1300ROBERT FITZMAURICEWESTON HEIGHTS NORTHT.E.S.C. PLANC2.0 Horiz. ScaleVert. ScaleProject No.DateNo.ClientContactApproved ByChecked ByDesigned ByDrawn ByREVISIONSDateDescriptionKnow what'sbelow. before you dig.Call R 10416U16-003996 CONSTRUCTION SEQUENCE DATUM BENCHMARK CERTIFIED EROSION CONTROL SPECIALIST NPDES PERMIT #: Weston Heights North Technical Information Report KCRTS – Weston Heights North – TESC . Flow Frequency Analysis Time Series File:tesc.tsf Project Location:Landsburg ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.206 6 2/08/01 19:00 0.705 1 100.00 0.990 0.073 8 5/06/02 7:15 0.544 2 25.00 0.960 0.347 4 6/25/03 2:15 0.350 3 10.00 0.900 0.544 2 8/25/04 23:30 0.347 4 5.00 0.800 0.162 7 6/10/05 13:45 0.312 5 3.00 0.667 0.350 3 10/22/05 16:15 0.206 6 2.00 0.500 0.312 5 11/21/06 8:15 0.162 7 1.30 0.231 0.705 1 1/09/08 7:30 0.073 8 1.10 0.091 Computed Peaks 0.651 50.00 0.980 Weston Heights North Technical Information Report Weston Heights North Technical Information Report APPENDIX 8B SWPPP PROJECT SUMMARY Weston Heights North 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 November 2016 Install ESC Measures November 2016 Construction End Date July 2017 CONSTRUCTION BMP LIST: Silt Fence (STD. PLAN 214.00) Stabilized Construction Entrance (STD. PLAN 215.10) Filter Fabric Protection (STD. PLAN 216.20) Sediment Trap (STD. PLAN 211.00) Temporary and Permanent Seeding (BMP C120) Plastic Covering (STD. PLAN 213.30) Interceptor Dike and Swale (STD. PLAN 217.00 & 217.10) Check Dams (STD. PLAN 217.40) !"#$ %##!&#’#% ###% %##%#!(’ $#(# !" Weston Heights North Technical Information Report APPENDIX 8C ALTERNATIVE BMPs Weston Heights North 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 North Technical Information Report APPENDIX 8D GENERAL PERMIT Weston Heights North Technical Information Report Construction Stormwater General Permit When available, the Department of Ecology assigned General Permit Number will be provided: # A copy of the construction stormwater general permit coverage documents will be added to this appendix during the preconstruction meeting. Weston Heights North Technical Information Report APPENDIX 8E SITE LOG & INSPECTION FORMS Weston Heights North 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 North 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 North 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 North 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 North 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 North 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 North Technical Information Report SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT Weston Heights North 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. Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date Prepared: Name:PE Registration No:Firm Name:Firm Address:Phone No.Email Address:Project Name: Project Owner:CED Plan # (LUA): Phone:CED Permit # (U):Address: Site Address:Street Intersection: Addt'l Project Owner:Parcel #(s): Phone:Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NOWater Service Provided by:If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: Abbreviated Legal Description:702 Nile Ave NE Renton, WA 980592913 5th Ave NE, Ste 201,Nile Ave NE & NE 7th PL16‐003996206‐276‐75269/26/2016Prepared by:FOR CONSTRUCTIONProject Phase 1smesic@sdaengineers.comScott MesicPE Registration No. 39377S.D.A.1724 W. Marine View Dr #140 Everett, 98201425‐486‐6533SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONKC WATER DISTRICT 90CITY OF RENTON1 Select the current project status/phase from the following options: For Approval ‐ Preliminary Data Enclosed, pending approval from the City; For Construction ‐ Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout ‐ Final Costs and Quantities Enclosed for Project Close‐out SubmittalEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and Grading Utility ProvidersN/AProject Location and Description Project Owner InformationWeston Heights North Puyallup, WA 983721123059002, 947794 TR‐LProspect Development, LLC16‐000140Page 2 of 14Ref 8‐H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996UnitReference # Price Unit Quantity CostBackfill & compaction‐embankmentESC‐16.50$ CYCheck dams, 4" minus rockESC‐2SWDM 5.4.6.380.00$ Each 5400.00Catch Basin ProtectionESC‐335.50$ Each 14497.00Crushed surfacing 1 1/4" minusESC‐4WSDOT 9‐03.9(3)95.00$ CYDitchingESC‐59.00$ CYExcavation‐bulkESC‐62.00$ CY 31306,260.00Fence, siltESC‐7SWDM 5.4.3.11.50$ LF 626939.00Fence, Temporary (NGPE)ESC‐81.50$ LFGeotextile FabricESC‐92.50$ SYHay Bale Silt TrapESC‐100.50$ EachHydroseedingESC‐11SWDM 5.4.2.40.80$ SYInterceptor Swale / DikeESC‐121.00$ LF 398398.00Jute MeshESC‐13SWDM 5.4.2.23.50$ SYLevel SpreaderESC‐141.75$ LFMulch, by hand, straw, 3" deepESC‐15SWDM 5.4.2.12.50$ SYMulch, by machine, straw, 2" deepESC‐16SWDM 5.4.2.12.00$ SYPiping, temporary, CPP, 6"ESC‐1712.00$ LFPiping, temporary, CPP, 8"ESC‐1814.00$ LFPiping, temporary, CPP, 12"ESC‐1918.00$ LFPlastic covering, 6mm thick, sandbaggedESC‐20SWDM 5.4.2.34.00$ SYRip Rap, machine placed; slopesESC‐21WSDOT 9‐13.1(2)45.00$ CYRock Construction Entrance, 50'x15'x1'ESC‐22SWDM 5.4.4.11,800.00$ EachRock Construction Entrance, 100'x15'x1'ESC‐23SWDM 5.4.4.13,200.00$ Each 13,200.00Sediment pond riser assemblyESC‐24SWDM 5.4.5.22,200.00$ EachSediment trap, 5' high berm ESC‐25SWDM 5.4.5.119.00$ LFSed. trap, 5' high, riprapped spillway berm section ESC‐26SWDM 5.4.5.170.00$ LF 825,740.00Seeding, by handESC‐27SWDM 5.4.2.41.00$ SYSodding, 1" deep, level groundESC‐28SWDM 5.4.2.58.00$ SYSodding, 1" deep, sloped groundESC‐29SWDM 5.4.2.510.00$ SYTESC SupervisorESC‐30110.00$ HR 8880.00Water truck, dust controlESC‐31SWDM 5.4.7140.00$ HR 162,240.00UnitReference # Price Unit Quantity Cost2,000.00$ LS 12,000.00EROSION/SEDIMENT SUBTOTAL: 22,554.00SALES TAX @ 9.5% 2,142.63EROSION/SEDIMENT TOTAL: 24,696.63(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)Removal of Exist. StructureWRITE‐IN‐ITEMS Page 3 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostGENERAL ITEMS Backfill & Compaction‐ embankment GI‐16.00$ CY 100600.00Backfill & Compaction‐ trench GI‐29.00$ CYClear/Remove Brush, by hand (SY) GI‐31.00$ SYBollards ‐ fixed GI‐4 240.74$ EachBollards ‐ removable GI‐5 452.34$ EachClearing/Grubbing/Tree Removal GI‐6 10,000.00$ Acre 0.282,800.000.191,900.001.2612,600.00Excavation ‐ bulk GI‐72.00$ CYExcavation ‐ Trench GI‐85.00$ CYFencing, cedar, 6' high GI‐9 20.00$ LFFencing, chain link, 4' GI‐10 38.31$ LFFencing, chain link, vinyl coated, 6' high GI‐11 20.00$ LFFencing, chain link, gate, vinyl coated, 20' GI‐12 1,400.00$ EachFill & compact ‐ common barrow GI‐13 25.00$ CY 1303,250.002005,000.00280070,000.00Fill & compact ‐ gravel base GI‐14 27.00$ CYFill & compact ‐ screened topsoil GI‐15 39.00$ CYGabion, 12" deep, stone filled mesh GI‐16 65.00$ SYGabion, 18" deep, stone filled mesh GI‐17 90.00$ SYGabion, 36" deep, stone filled mesh GI‐18 150.00$ SYGrading, fine, by hand GI‐19 2.50$ SYGrading, fine, with grader GI‐20 2.00$ SY 179358.009421,884.0048789,756.00Monuments, 3' Long GI‐21 250.00$ EachSensitive Areas Sign GI‐22 7.00$ Each 856.00Sodding, 1" deep, sloped ground GI‐23 8.00$ SYSurveying, line & grade GI‐24 850.00$ Day 1850.00Surveying, lot location/lines GI‐25 1,800.00$ Acre 0.21378.002.264,068.00Topsoil Type A (imported) GI‐26 28.50$ CYTraffic control crew ( 2 flaggers )GI‐27 120.00$ HR 101,200.00Trail, 4" chipped wood GI‐28 8.00$ SYTrail, 4" crushed cinder GI‐29 9.00$ SYTrail, 4" top course GI‐30 12.00$ SYConduit, 2" GI‐31 5.00$ LF 7263,630.00Wall, retaining, concrete GI‐32 55.00$ SFWall, rockery GI‐33 15.00$ SFSUBTOTAL THIS PAGE:7,608.00 9,162.00 101,560.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)Page 4 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000sy RI‐1 30.00$ SY 50915,270.00AC Grinding, 4' wide machine 1000‐2000sy RI‐2 16.00$ SYAC Grinding, 4' wide machine > 2000sy RI‐3 10.00$ SYAC Removal/Disposal RI‐4 35.00$ SY 56119,635.00Barricade, Type III ( Permanent )RI‐5 56.00$ LFGuard Rail RI‐6 30.00$ LFCurb & Gutter, rolled RI‐7 17.00$ LFCurb & Gutter, vertical RI‐8 12.50$ LF 7078,837.50Curb and Gutter, demolition and disposal RI‐9 18.00$ LF 671,206.00Curb, extruded asphalt RI‐10 5.50$ LFCurb, extruded concrete RI‐11 7.00$ LFSawcut, asphalt, 3" depth RI‐12 1.85$ LF 9001,665.00Sawcut, concrete, per 1" depth RI‐13 3.00$ LFSealant, asphalt RI‐14 2.00$ LF 9001,800.00Shoulder, gravel, 4" thick RI‐15 15.00$ SYSidewalk, 4" thick RI‐16 38.00$ SY 32212,236.00Sidewalk, 4" thick, demolition and disposal RI‐17 32.00$ SYSidewalk, 5" thick RI‐18 41.00$ SY 25210,332.00Sidewalk, 5" thick, demolition and disposal RI‐19 40.00$ SYSign, Handicap RI‐20 85.00$ EachStriping, per stall RI‐21 7.00$ EachStriping, thermoplastic, ( for crosswalk )RI‐22 3.00$ SFStriping, 4" reflectorized line RI‐23 0.50$ LF 6934.50Additional 2.5" Crushed Surfacing RI‐24 3.60$ SYHMA 1/2" Overlay 1.5" RI‐25 14.00$ SYHMA 1/2" Overlay 2" RI‐26 18.00$ SYHMA Road, 2", 4" rock, First 2500 SY RI‐27 28.00$ SYHMA Road, 2", 4" rock, Qty. over 2500SY RI‐28 21.00$ SYHMA Road, 4", 6" rock, First 2500 SY RI‐29 45.00$ SY 72632,670.00HMA Road, 4", 6" rock, Qty. over 2500 SY RI‐30 37.00$ SYHMA Road, 4", 4.5" ATB RI‐31 38.00$ SYGravel Road, 4" rock, First 2500 SY RI‐32 15.00$ SYGravel Road, 4" rock, Qty. over 2500 SY RI‐33 10.00$ SYThickened Edge RI‐34 8.60$ LFSUBTOTAL THIS PAGE:81,118.00 22,568.00(B)(C)(D)(E)Page 5 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B) (C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrow PL‐1 21.00$ SY2" AC, 1.5" top course & 2.5" base course PL‐2 28.00$ SY4" select borrow PL‐35.00$ SY1.5" top course rock & 2.5" base course PL‐4 14.00$ SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street Trees LA‐1 30,374.00$ LS 130,374.00Median Landscaping LA‐2LSRight‐of‐Way Landscaping LA‐3 $10,000 LS 110,000.00Wetland Landscaping LA‐4 18,531.00$ LS 118,531.00SUBTOTAL LANDSCAPING & VEGETATION:10,000.00 30,374.00 18,531.00(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.Signs TR‐18.00$ EACH 432.00Street Light System ( # of Poles) TR‐2 35,000.00$ LS 135,000.00Traffic Signal TR‐3Traffic Signal Modification TR‐4SUBTOTAL TRAFFIC & LIGHTING:35,032.00(B)(C)(D)(E)WRITE‐IN‐ITEMSLandscaping for Tract C, 6" Hog Fuel path. 26,951.00$ LS 126,951.007" HMA, 6" Rock 75.00$ SY 24518,375.00SUBTOTAL WRITE‐IN ITEMS:18,375.00 26,951.00STREET AND SITE IMPROVEMENTS SUBTOTAL: 152,133.00 62,104.00 147,042.00SALES TAX @ 9.5% 14,452.64 5,899.88 13,968.99STREET AND SITE IMPROVEMENTS TOTAL: 166,585.64 68,003.88 161,010.99(B)(C)(D)(E)Page 6 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostDRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D‐1 26.00$ SY* (CBs include frame and lid)Beehive D‐2 90.00$ EachThrough‐curb Inlet Framework D‐3 400.00$ EachCB Type ID‐4 1,500.00$ Each 34,500.00CB 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 for additional depth over 4' D‐9 495.00$ FTCB Type II, 60" diameter D‐10 2,800.00$ Each for additional depth over 4' D‐11 600.00$ FTCB Type II, 72" diameter D‐12 6,000.00$ Each for additional depth over 4' D‐13 850.00$ FTCB Type II, 96" diameter D‐14 14,000.00$ Each for additional depth over 4' D‐15 925.00$ FTTrash Rack, 12" D‐16 350.00$ EachTrash Rack, 15" D‐17 410.00$ EachTrash Rack, 18" D‐18 480.00$ EachTrash Rack, 21" D‐19 550.00$ EachCleanout, PVC, 4" D‐20 150.00$ EachCleanout, PVC, 6" D‐21 170.00$ Each 2340.00Cleanout, PVC, 8" D‐22 200.00$ EachCulvert, PVC, 4" (Not allowed in ROW)D‐23 10.00$ LF 4154,150.00Culvert, PVC, 6" (Not allowed in ROW)D‐24 13.00$ LFCulvert, PVC, 8" (Not allowed in ROW)D‐25 15.00$ LFCulvert, PVC, 12" (Not allowed in ROW)D‐26 23.00$ LFCulvert, PVC, 15" (Not allowed in ROW)D‐27 35.00$ LFCulvert, PVC, 18" (Not allowed in ROW)D‐28 41.00$ LFCulvert, PVC, 24" (Not allowed in ROW)D‐29 56.00$ LFCulvert, PVC, 30" (Not allowed in ROW)D‐30 78.00$ LFCulvert, PVC, 36" (Not allowed in ROW)D‐31 130.00$ LFCulvert, CMP, 8" D‐32 19.00$ LFCulvert, CMP, 12" D‐33 29.00$ LFSUBTOTAL THIS PAGE:4,500.00 4,490.00(B) (C) (D) (E)Quantity Remaining (Bond Reduction) (B) (C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 7 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B) (C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15" D‐34 35.00$ LFCulvert, CMP, 18" D‐35 41.00$ LFCulvert, CMP, 24" D‐36 56.00$ LFCulvert, CMP, 30" D‐37 78.00$ LFCulvert, CMP, 36" D‐38 130.00$ LFCulvert, CMP, 48" D‐39 190.00$ LFCulvert, CMP, 60" D‐40 270.00$ LFCulvert, CMP, 72" D‐41 350.00$ LFCulvert, Concrete, 8" D‐42 42.00$ LFCulvert, Concrete, 12" D‐43 48.00$ LFCulvert, Concrete, 15" D‐44 78.00$ LFCulvert, Concrete, 18" D‐45 48.00$ LFCulvert, Concrete, 24" D‐46 78.00$ LFCulvert, Concrete, 30" D‐47 125.00$ LFCulvert, Concrete, 36" D‐48 150.00$ LFCulvert, Concrete, 42" D‐49 175.00$ LFCulvert, Concrete, 48" D‐50 205.00$ LFCulvert, CPE, 6" (Not allowed in ROW)D‐51 14.00$ LFCulvert, CPE, 8" (Not allowed in ROW)D‐52 16.00$ LFCulvert, CPE, 12" (Not allowed in ROW)D‐53 24.00$ LFCulvert, CPE, 15" (Not allowed in ROW)D‐54 35.00$ LFCulvert, CPE, 18" (Not allowed in ROW)D‐55 41.00$ LFCulvert, CPE, 24" (Not allowed in ROW)D‐56 56.00$ LFCulvert, CPE, 30" (Not allowed in ROW)D‐57 78.00$ LFCulvert, CPE, 36" (Not allowed in ROW)D‐58 130.00$ LFCulvert, LCPE, 6" D‐59 60.00$ LFCulvert, LCPE, 8" D‐60 72.00$ LFCulvert, LCPE, 12" D‐61 84.00$ LFCulvert, LCPE, 15" D‐62 96.00$ LFCulvert, LCPE, 18" D‐63 108.00$ LFCulvert, LCPE, 24" D‐64 120.00$ LFCulvert, LCPE, 30" D‐65 132.00$ LFCulvert, LCPE, 36" D‐66 144.00$ LFCulvert, LCPE, 48" D‐67 156.00$ LFCulvert, LCPE, 54" D‐68 168.00$ LFSUBTOTAL THIS PAGE:(B) (C) (D) (E)Page 8 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B) (C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60" D‐69 180.00$ LFCulvert, LCPE, 72" D‐70 192.00$ LFCulvert, HDPE, 6" D‐71 42.00$ LF 321,344.00371,554.00873,654.00Culvert, HDPE, 8" D‐72 42.00$ LFCulvert, HDPE, 12" D‐73 74.00$ LF 32423,976.00Culvert, HDPE, 15" D‐74 106.00$ LFCulvert, HDPE, 18" D‐75 138.00$ LFCulvert, HDPE, 24" D‐76 221.00$ LFCulvert, HDPE, 30" D‐77 276.00$ LFCulvert, HDPE, 36" D‐78 331.00$ LFCulvert, HDPE, 48" D‐79 386.00$ LFCulvert, HDPE, 54" D‐80 441.00$ LFCulvert, HDPE, 60" D‐81 496.00$ LFCulvert, HDPE, 72" D‐82 551.00$ LFPipe, Polypropylene, 6" D‐83 84.00$ LFPipe, Polypropylene, 8" D‐84 89.00$ LFPipe, Polypropylene, 12" D‐85 95.00$ LFPipe, Polypropylene, 15" D‐86 100.00$ LFPipe, Polypropylene, 18" D‐87 106.00$ LFPipe, Polypropylene, 24" D‐88 111.00$ LFPipe, Polypropylene, 30" D‐89 119.00$ LFPipe, Polypropylene, 36" D‐90 154.00$ LFPipe, Polypropylene, 48" D‐91 226.00$ LFPipe, Polypropylene, 54" D‐92 332.00$ LFPipe, Polypropylene, 60" D‐93 439.00$ LFPipe, Polypropylene, 72" D‐94 545.00$ LFCulvert, DI, 6" D‐95 61.00$ LFCulvert, DI, 8" D‐96 84.00$ LFCulvert, DI, 12" D‐97 106.00$ LFCulvert, DI, 15" D‐98 129.00$ LFCulvert, DI, 18" D‐99 152.00$ LFCulvert, DI, 24" D‐100 175.00$ LFCulvert, DI, 30" D‐101 198.00$ LFCulvert, DI, 36" D‐102 220.00$ LFCulvert, DI, 48" D‐103 243.00$ LFCulvert, DI, 54" D‐104 266.00$ LFCulvert, DI, 60" D‐105 289.00$ LFCulvert, DI, 72" D‐106 311.00$ LFSUBTOTAL THIS PAGE:25,320.00 1,554.00 3,654.00(B) (C) (D) (E)Page 9 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B) (C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD‐19.50$ CYFlow Dispersal Trench (1,436 base+) SD‐3 28.00$ LF French Drain (3' depth) SD‐4 26.00$ LF 671,742.00Geotextile, laid in trench, polypropylene SD‐53.00$ SYMid‐tank Access Riser, 48" dia, 6' deep SD‐6 2,000.00$ EachPond Overflow Spillway SD‐7 16.00$ SYRestrictor/Oil Separator, 12" SD‐8 1,150.00$ EachRestrictor/Oil Separator, 15" SD‐9 1,350.00$ EachRestrictor/Oil Separator, 18" SD‐10 1,700.00$ EachRiprap, placed SD‐11 42.00$ CYTank End Reducer (36" diameter) SD‐12 1,200.00$ EachInfiltration pond testing SD‐13 125.00$ HRPermeable Pavement SD‐14Permeable Concrete Sidewalk SD‐15Culvert, Box __ ft x __ ft SD‐16SUBTOTAL SPECIALTY DRAINAGE ITEMS:1,742.00(B) (C) (D) (E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention Pond SF‐1Each Detention Tank SF‐2Each Detention Vault SF‐3Each Infiltration Pond SF‐4Each Infiltration Tank SF‐5Each Infiltration Vault SF‐6Each Infiltration Trenches SF‐7Each Basic Biofiltration Swale SF‐8Each Wet Biofiltration Swale SF‐9Each Wetpond SF‐10 Each Wetvault SF‐11 Each Sand Filter SF‐12 Each Sand Filter Vault SF‐13 Each Linear Sand Filter SF‐14 Each StormFilter SF‐15 Each Rain Garden SF‐16 Each SUBTOTAL STORMWATER FACILITIES:(B) (C) (D) (E)Page 10 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostQuantity Remaining (Bond Reduction) (B) (C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE‐IN‐ITEMSAdjust Exist Control Structure WI‐1 5,000.00$ LS 15,000.00Yard Drain WI‐2 170.00$ EA 3510.00WI‐3WI‐4WI‐5WI‐6WI‐7WI‐8WI‐9WI‐10WI‐11WI‐12WI‐13WI‐14WI‐15SUBTOTAL WRITE‐IN ITEMS:5,510.00DRAINAGE AND STORMWATER FACILITIES SUBTOTAL: 4,500.00 11,742.00SALES TAX @ 9.5% 427.50 1,115.49DRAINAGE AND STORMWATER FACILITIES TOTAL: 4,927.50 12,857.49(B) (C) (D) (E)Page 11 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostConnection to Existing Watermain W‐1 2,000.00$ EachDuctile Iron Watermain, CL 52, 4 Inch Diameter W‐2 50.00$ LFDuctile Iron Watermain, CL 52, 6 Inch Diameter W‐3 56.00$ LFDuctile Iron Watermain, CL 52, 8 Inch Diameter W‐4 60.00$ LFDuctile Iron Watermain, CL 52, 10 Inch Diameter W‐5 70.00$ LFDuctile Iron Watermain, CL 52, 12 Inch Diameter W‐6 80.00$ LFGate Valve, 4 inch Diameter W‐7 500.00$ EachGate Valve, 6 inch Diameter W‐8 700.00$ EachGate Valve, 8 Inch Diameter W‐9 800.00$ EachGate Valve, 10 Inch Diameter W‐10 1,000.00$ EachGate Valve, 12 Inch Diameter W‐11 1,200.00$ EachFire Hydrant Assembly W‐12 4,000.00$ EachPermanent Blow‐Off Assembly W‐13 1,800.00$ EachAir‐Vac Assembly, 2‐Inch Diameter W‐14 2,000.00$ EachAir‐Vac Assembly, 1‐Inch Diameter W‐15 1,500.00$ EachCompound Meter Assembly 3‐inch Diameter W‐16 8,000.00$ EachCompound Meter Assembly 4‐inch Diameter W‐17 9,000.00$ EachCompound Meter Assembly 6‐inch Diameter W‐18 10,000.00$ EachPressure Reducing Valve Station 8‐inch to 10‐inch W‐19 20,000.00$ EachWATER SUBTOTAL:SALES TAX @ 9.5%WATER TOTAL:(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B) (C)Page 12 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 CED Permit #:16‐003996Existing Future Public PrivateRight‐of‐Way Improvements Improvements(D)(E)Description No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Quant. CostClean Outs SS‐1 1,000.00$ EachGrease Interceptor, 500 gallon SS‐2 8,000.00$ EachGrease Interceptor, 1000 gallon SS‐3 10,000.00$ EachGrease Interceptor, 1500 gallon SS‐4 15,000.00$ EachSide Sewer Pipe, PVC. 4 Inch Diameter SS‐5 80.00$ LFSide Sewer Pipe, PVC. 6 Inch Diameter SS‐6 95.00$ LF 605,700.00726,840.00484,560.00Sewer Pipe, PVC, 8 inch Diameter SS‐7 105.00$ LFSewer Pipe, PVC, 12 Inch Diameter SS‐8 120.00$ LFSewer Pipe, DI, 8 inch Diameter SS‐9 115.00$ LFSewer Pipe, DI, 12 Inch Diameter SS‐10 130.00$ LFManhole, 48 Inch Diameter SS‐11 6,000.00$ EachManhole, 54 Inch Diameter SS‐13 6,500.00$ EachManhole, 60 Inch Diameter SS‐15 7,500.00$ EachManhole, 72 Inch Diameter SS‐17 8,500.00$ EachManhole, 96 Inch Diameter SS‐19 14,000.00$ EachPipe, C‐900, 12 Inch Diameter SS‐21 180.00$ LFOutside Drop SS‐24 1,500.00$ LSInside Drop SS‐25 1,000.00$ LSSewer Pipe, PVC, ____ Inch Diameter SS‐26Lift Station (Entire System) SS‐27 LSSANITARY SEWER SUBTOTAL:5,700.00 6,840.00 4,560.00SALES TAX @ 9.5% 541.50 649.80 433.20SANITARY SEWER TOTAL: 6,241.50 7,489.80 4,993.20(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B) (C)Page 13 of 14Ref 8‐H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430‐7200Date:Name:Project Name: PE Registration No:CED Plan # (LUA):Firm Name:CED Permit # (U):Firm Address:Site Address:Phone No.Parcel #(s):Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a) (a)24,696.63$ Existing Right‐of‐Way Improvements Subtotal (b) (b)172,827.14$ Future Public Improvements Subtotal (c) (c)75,493.68$ Stormwater & Drainage Facilities Subtotal (d) (d)17,784.99$ Bond Reduction (Quantity Remaining)2(e) (e)‐$ Site RestorationCivil Construction PermitMaintenance Bond53,221.16$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only ‐ May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. R((b)+(c)+(d)) x 150%EST1((b) + (c) + (d)) x 20%‐$ MAINTENANCE BOND */**(after final acceptance of construction)24,696.63$ 172,827.14$ 399,158.71$ 37,044.95$ ‐$ 75,493.68$ 17,784.99$ S(e) x 150%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS9/26/2016Scott MesicPE Registration No. 39377S.D.A.T(P +R ‐ S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)425‐486‐6533smesic@sdaengineers.comWeston Heights North16‐000140702 Nile Ave NE Renton, WA 980591123059002, 947794 TR‐LFOR CONSTRUCTION16‐0039961724 W. Marine View Dr #140 Everett, 98201436,203.65$ P (a) x 150%Page 14 of 14Ref 8‐H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 06/14/2016Printed 10/5/2016 Weston Heights North Technical Information Report SECTION 10 OPERATIONS AND MAINTENANCE MANUAL Weston Heights North Technical Information Report Operations and Maintenance Manual The following pages are selections from Appendix A of the 2009 King County Stormwater Design Manual, applicable to this project: Weston Heights North Technical Information Report NO. 1 – DETENTION PONDS Maintenance Component Defect or Problem Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to 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. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Top or Side Slopes of Dam, Berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are not a threat or not interfering with access or maintenance, they do not need to be removed. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Storage Area Sediment accumulation Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth; pond reseeded if necessary to control erosion. Liner damaged (If Applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Inlet/Outlet Pipe. Sediment accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Emergency Overflow/Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. Rock missing Only one layer of rock exists above native soil in area five square feet or larger or any exposure of native soil on the spillway. Spillway restored to design standards. Weston Heights North Technical Information Report NO. 3 – DETENTION TANKS AND VAULTS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to 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. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non-floatables). No trash or debris in vault. 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. Tank Structure Plugged air vent Any blockage of the vent.Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. 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. Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged 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. Weston Heights North Technical Information Report NO. 3 – DETENTION TANKS AND VAULTS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks.Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat 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. Weston Heights North Technical Information Report NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/ 3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. 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. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/ inch wide at 4 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. 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. FROP-T Section Damage 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. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Weston Heights North Technical Information Report NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR person. 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. Orifice Plate 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. Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe 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. Deformed or damaged lip Lip of overflow pipe is bent or deformed.Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If Applicable) Unsafe grate opening Grate with opening wider than 7/ inch. 8 Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate.Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to Remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance Weston Heights North Technical Information Report NO. 5 – CATCH BASINS AND MANHOLES Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Structure 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 and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/ the depth from the bottom of basin to invert the 3 lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/ inch wide at 4 the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. 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. Weston Heights North Technical Information Report NO. 5 – CATCH BASINS AND MANHOLES person. Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/ inch. 8 Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to Remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance Weston Heights North Technical Information Report NO. 6 – CONVEYANCE PIPES AND DITCHES Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/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. 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. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to 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. 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. Weston Heights North Technical Information Report NO. 9 – FENCING Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed. Site Erosion or holes under fence Erosion or holes more than 4 inches high and 12- 18 inches wide permitting access through an opening under a fence. No access under the fence. Wood Posts, Boards and Cross Members Missing or damaged parts Missing or broken boards, post out of plumb by more than 6 inches or cross members broken. No gaps on fence due to missing or broken boards, post plumb to within 1 ½ inches, cross members sound. Weakened by rotting or insects Any part showing structural deterioration due to rotting or insect damage. All parts of fence are structurally sound. Damaged or failed post foundation Concrete or metal attachments deteriorated or unable to support posts. Post foundation capable of supporting posts even in strong wind. Metal Posts, Rails and Fabric Damaged parts Post out of plumb more than 6 inches.Post plumb to within 1 ½ inches. Top rails bent more than 6 inches.Top rail free of bends greatyer than 1 inch. Any part of fence (including post, top rails, and fabric) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Missing or loose tension wire.Tension wire in place and holding fabric. Deteriorated point or protective coating Part or parts that have a rusting or scaling condition that has affected ttld Structurally adequate posts or parts with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8- inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. Weston Heights North Technical Information Report NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Chain Link Fencing Gate Damaged or missing members Missing gate.Gates in place. Broken or missing hinges such that gate cannot be easily opened and closed by a maintenance person. Hinges intact and lubed. Gate is working freely. Gate is out of plumb more than 6 inches and more than 1 foot out of design alignment. Gate is aligned and vertical. Missing stretcher bar, stretcher bands, and ties.Stretcher bar, bands, and ties in place. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. Bar Gate Damaged or missing cross bar Cross bar does not swing open or closed, is missing or is bent to where it does not prevent vehicle access. Cross bar swings fully open and closed and prevents vehicle access. Locking mechanism does not lock gate Locking device missing, no-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Support post damaged Support post does not hold cross bar up.Cross bar held up preventing vehicle access into facility. Bollards Damaged or missing Bollard broken, missing, does not fit into support hole or hinge broken or missing. No access for motorized vehicles to get into facility. 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. Boulders Dislodged Boulders not located to prevent motorized vehicle access. No access for motorized vehicles to get into facility. Circumvented Motorized vehicles going around or between boulders. No access for motorized vehicles to get into facility. Weston Heights North Technical Information Report NO. 11 – GROUNDS (LANDSCAPING) Maintenance Component Defect or Problem Conditions When Maintenance is Needed Results Expected When Maintenance is Performed Site 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. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. Weston Heights North Technical Information Report NO. 12 – ACCESS ROADS Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Site Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet (i.e., trash and debris would fill up one standards size garbage can). Roadway drivable by maintenance vehicles. Debris which could damage vehicle tires or prohibit use of road. Roadway drivable by maintenance vehicles. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Blocked roadway Any obstruction which reduces clearance above road surface to less than 14 feet. Roadway overhead clear to 14 feet high. Any obstruction restricting the access to a 10- to 12 foot width for a distance of more than 12 feet or any point restricting access to less than a 10 foot width. At least 12-foot of width on access road. Road Surface Erosion, settlement, potholes, soft spots, ruts Any surface defect which hinders or prevents maintenance access. Road drivable by maintenance vehicles. Vegetation on road surface Trees or other vegetation prevent access to facility by maintenance vehicles. Maintenance vehicles can access facility. Shoulders and Ditches Erosion Erosion within 1 foot of the roadway more than 8 inches wide and 6 inches deep. Shoulder free of erosion and matching the surrounding road. Weeds and brush Weeds and brush exceed 18 inches in height or hinder maintenance access. Weeds and brush cut to 2 inches in height or cleared in such a way as to allow maintenance access. Modular Grid Pavement Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damaged or missing Access surface compacted because of broken on missing modular block. Access road surface restored so road infiltrates. Weston Heights North Technical Information Report NO. 16 – WETPOND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Site Trash and debris Any trash and debris accumulated on the wetpond site. Wetpond site free of any trash or debris. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to 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. Grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Side Slopes of Dam, Berm, internal berm or Embankment Rodent holes Any evidence of rodent holes if facility is acting as a dam or berm, or any evidence of water piping through dam or berm via rodent holes. Rodents removed or destroyed and dam or berm repaired. Tree growth Tree growth threatens integrity of dams, berms or slopes, does not allow maintenance access, or interferes with maintenance activity. If trees are not a threat to dam, berm or embankment integrity, are not interfering with access or maintenance or leaves do not cause a plugging problem they do not need to be removed. Trees do not hinder facility performance or maintenance activities. Erosion Eroded damage over 2 inches deep where cause of damage is still present or where there is potential for continued erosion. Any erosion observed on a compacted slope. Slopes stabilized using appropriate erosion control measures. If erosion is occurring on compacted slope, a licensed civil engineer should be consulted to resolve source of erosion. Top or Side Slopes of Dam, Berm, internal berm or Embankment Settlement Any part of a dam, berm or embankment that has settled 4 inches lower than the design elevation. Top or side slope restored to design dimensions. If settlement is significant, a licensed civil engineer should be consulted to determine the cause of the settlement. Irregular surface on internal berm Top of berm not uniform and level.Top of berm graded to design elevation. Pond Areas Sediment accumulation (except first wetpool cell) Accumulated sediment that exceeds 10% of the designed pond depth. Sediment cleaned out to designed pond shape and depth. Sediment accumulation (first wetpool cell) Sediment accumulations in pond bottom that exceeds the depth of sediment storage (1 foot) plus 6 inches. Sediment storage contains no sediment. Liner damaged (If Applicable) Liner is visible or pond does not hold water as designed. Liner repaired or replaced. Water level (first wetpool cell) First cell empty, doesn't hold water.Water retained in first cell for most of the year. Algae mats (first wetpool cell) Algae mats develop over more than 10% of the water surface should be removed. Algae mats removed (usually in the late summer before Fall rains, especially in Sensitive Lake Protection Areas.) Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally. Valve won’t seal Valve does not seal completely.Valve completely seals closed. Weston Heights North Technical Information Report NO. 16 – WETPOND Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance Is Performed Emergency Overflow Spillway Tree growth Tree growth impedes flow or threatens stability of spillway. Trees removed. Rock Missing Only one layer of rock exists above native soil in area five square feet or larger, or any exposure of native soil at the top of out flow path of spillway. Rip- rap on inside slopes need not be replaced. Spillway restored to design standards. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged 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. Weston Heights North Technical Information Report NO. 17 – WETVAULT access. 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. Treatment Area 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. 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. 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, 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. Ventilation Ventilation area blocked or plugged.No reduction of ventilation area exists. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe.Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged 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. Gravity Drain Inoperable valve Valve will not open and close.Valve opens and closes normally. Valve won’t seal Valve does not seal completely.Valve completely seals closed. Access Manhole Access cover/lid 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. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks.Ladder meets design standards. Allows maintenance person safe