Loading...
HomeMy WebLinkAboutWeston Heights North TIR Utility I CommentsMarkup Summary Subject: Callout Page: Page 229 Lock: Unlocked Status: Checkmark: Checked Author: IFitz-James Date: 8/17/2016 9:29:16 AM Color: Depth: NO GRADING PERMIT REQUIRED Callout (3) Subject: Callout Page: Page 248 Lock: Unlocked Status: Checkmark: Checked Author: IFitz-James Date: 8/11/2016 10:45:22 AM Color: Depth: REFERENCE COR STD. PLANS Subject: Cloud Page: Page 86 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/17/2016 8:54:19 AM Color: Depth: Cloud (4) Subject: Cloud Page: Page 243 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/16/2016 11:34:49 AM Color: Depth: Subject: Cloud Page: Page 248 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/11/2016 10:44:42 AM Color: Depth: ton ton of Ecology NO GRADINGPERMIT REQUIRED MP C200) REFERENCE COR STD. PLANS Name(s) Phone Number trol Lead* Puget Sound Office (425) 649-7000 Northwest Region (425) 649-7000 decided upon and included in the spaces provided at the time of, or meet. EDULE: August 2016 Subject: Cloud Page: Page 248 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/11/2016 10:45:14 AM Color: Depth: Subject: Line Page: Page 229 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/17/2016 9:28:52 AM Color: Depth: Line (34) Subject: Line Page: Page 229 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/17/2016 9:29:02 AM Color: Depth: Subject: Text Box Page: Page 86 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/17/2016 8:54:15 AM Color: Depth: UPDATE CONVEYANCE CALCUATIONS TO ACCOUNT FOR NEW CATCH BASINS ALONG THE SOUTHERN FRONTAGE OF NE 7TH PLACE. Text Box (37) Subject: Text Box Page: Page 243 Lock: Unlocked Status: Checkmark: Unchecked Author: IFitz-James Date: 8/16/2016 11:34:45 AM Color: Depth: UPDATE AS NECESSARY  Construction Start Date August 2016  Install ESC Measures August 2016  Construction End Date November 2016 CONSTRUCTION BMP LIST:  Silt Fence (BMP C233)  Storm Drain Inlet Protection (BMP C220)  Materials on Hand (BMP C150) may also be applicable  Detention Pond Or Vault  Temporary and Permanent Seeding (BMP C120)  Plastic Covering (BMP C123)  Interceptor Dike and Swale (BMP C200)  Check Dams (BMP C207) Other Permits This project will require the following permits: Grading Permit - City of Renton Right-of-Way Use Permit - City of Renton Construction Stormwater Permit - WA Dept. of Ecology ermit ay Use Pe on Stormw UPDATE CONVEYANCECALCUATIONS TO ACCOUNTFOR NEW CATCH BASINSALONG THE SOUTHERNFRONTAGE OF NE 7TH PLACE. UPDATE AS NECESSARY July 7, 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: Riley O'Keefe on 7/6/16 R:\Projects\349 (prospect development)\007-15 (Weston North)\Technical\Reports\2016-05-25 TIR\2016-05-25 WHN Drainage Report.docm 07-07-16 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 plat action. 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: ______________________ TAYLOR DEVELOPMENT (425) 869-1300 15 LAKE BELLEVUE DRIVE #102 BELLEVUE, WA 98005 SCOTT MESIC SDA ENGINEERS (425) 486-6533 WESTON HEIGHTS NORTH 23N 5E 11 702 NILE AVE NE RENTON, WA 98056 N/A 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 CITY OF RENTON CEDAR RIVER ON-SITE; NOT DISTURBED ALDERWOOD <10%LOW/MODERATE 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: 1 N/A VAULT/POND TO BE ASSIGNED AT PRECONSTRUCTION. 1 - EXISTING COMBINED POND, 1 - DETENTION POND, 1 - COMBINED VAULT SFR N/A THE PROJECT IS 1 TDA WHICH DISCHARGES TO AN EXISTING PIPED CONVEYANCE SYSTEM ALONG NILE AVE NE. 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 ________________ ________________ ________________ ________________ ________________ ________________ ________________ VAULT/POND (2) ALL EXISTING VAULT/POND STORMFILTER BOTH EXISTING EXISTING 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 (serving Weston Heights North lots 4-6), the Weston Heights west combined detention vault (mitigates against the released yard/landscape bypass areas of Weston Heights North lots 2-3), 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. The east half of the project generally falls toward the west, and is collected in the wetland area in the center of the project. Water from this wetland enters an overflow device just north of Orcas Ave W, then is conveyed to the Nile Ave 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 Project Location 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). 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 to distribute the runoff into the central wetland, thereby satisfying the hydroperiod. 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. 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. Weston Heights North Technical Information Report 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. 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 (Lots 2-3), 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’. 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 (entire lot area), 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. 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, 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. Weston Heights North Technical Information Report 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 4-6 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 eastern most extents of the Weston Heights North project (Lot 1), in addition to the buffer area to the north and west, contributing flow to this wetland. The Weston Heights areas that contribute flow to the wetland include the entire East basin and a portion of the West basin. As a result of these two separate projects, Weston Heights North 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 from a portion of the undisturbed Weston Heights North Lot 1, will be redirected into the wetland via a gravel trench. The gravel trench will be located along the southern property limits of Tract A, and will collect surface runoff along the contributing portion of Weston Heights Lot 1. The gravel trench will act as a level spreader above the northeastern edge of the wetland. Flows will slowly matriculate along the gravel trench, from west to east, and enter the wetland as overflow from the trench. The yard/landscape areas on Weston Heights North lots 2-3 will be allowed to sheet flow into the wetland as well. Refer to Appendix 4C for “Wetland Hydroperiod Calculations”. Weston Heights North Technical Information Report APPENDIX 4A FLOW CONTROL DESIGN CALCULATIONS NE 7TH PLNILE AVE NE 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 BNE 7TH PLNILE AVE NEWEST BASINEAST BASINWESTON HEIGHTS NORTHWESTBYPASSBASINEAST BYPASSBASINWESTON HEIGHTS NORTHWESTON HEIGHTS NORTHWESTON HEIGHTS NORTHWESTONHEIGHTSWESTONHEIGHTSDateProject No.DrawnDesignSheet:JDAEWJ6/9/16349-007-15DEVELOPED BASIN MAPWESTON HEIGHTS NORTHNWEST PROJECT BASINWEST BYPASS BASINEAST PROJECT BASINEAST BYPASS BASIN*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 0.373 4 2/09/01 2:00 0.683 1 100.00 0.990 0.220 8 12/03/01 17:00 0.451 2 25.00 0.960 0.367 5 9/10/03 15:00 0.429 3 10.00 0.900 0.429 3 8/26/04 1:00 0.373 4 5.00 0.800 0.353 7 10/28/04 18:00 0.367 5 3.00 0.667 0.366 6 10/22/05 17:00 0.366 6 2.00 0.500 0.451 2 11/21/06 9:00 0.353 7 1.30 0.231 0.683 1 1/09/08 7:00 0.220 8 1.10 0.091 Computed Peaks 0.606 50.00 0.980 Weston Heights 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 0.065 3 2/09/01 2:00 0.132 1 100.00 0.990 0.027 8 12/03/01 17:00 0.079 2 25.00 0.960 0.040 7 2/28/03 16:00 0.065 3 10.00 0.900 0.058 4 8/26/04 1:00 0.058 4 5.00 0.800 0.045 6 10/28/04 18:00 0.047 5 3.00 0.667 0.047 5 10/22/05 17:00 0.045 6 2.00 0.500 0.079 2 11/21/06 9:00 0.040 7 1.30 0.231 0.132 1 1/09/08 7:00 0.027 8 1.10 0.091 Computed Peaks 0.115 50.00 0.980 Weston Heights 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 3.80 509.60 11674. 0.268 0.034 0.00 3.81 509.61 11704. 0.269 0.036 0.00 3.82 509.62 11735. 0.269 0.039 0.00 3.83 509.63 11766. 0.270 0.040 0.00 3.84 509.64 11796. 0.271 0.040 0.00 Weston Heights North Technical Information Report 3.99 509.79 12257. 0.281 0.047 0.00 4.14 509.94 12718. 0.292 0.052 0.00 4.28 510.08 13148. 0.302 0.057 0.00 4.43 510.23 13609. 0.312 0.060 0.00 4.58 510.38 14070. 0.323 0.064 0.00 4.73 510.53 14531. 0.334 0.067 0.00 4.87 510.67 14961. 0.343 0.070 0.00 5.02 510.82 15421. 0.354 0.073 0.00 5.17 510.97 15882. 0.365 0.076 0.00 5.31 511.11 16312. 0.374 0.078 0.00 5.46 511.26 16773. 0.385 0.081 0.00 5.61 511.41 17234. 0.396 0.083 0.00 5.76 511.56 17695. 0.406 0.085 0.00 5.90 511.70 18125. 0.416 0.087 0.00 6.05 511.85 18586. 0.427 0.090 0.00 6.20 512.00 19046. 0.437 0.092 0.00 6.21 512.01 19077. 0.438 0.092 0.00 6.22 512.02 19108. 0.439 0.093 0.00 6.23 512.03 19139. 0.439 0.093 0.00 6.24 512.04 19169. 0.440 0.095 0.00 6.25 512.05 19200. 0.441 0.097 0.00 6.26 512.06 19231. 0.441 0.098 0.00 6.27 512.07 19261. 0.442 0.098 0.00 6.42 512.22 19722. 0.453 0.104 0.00 6.57 512.37 20183. 0.463 0.109 0.00 6.71 512.51 20613. 0.473 0.114 0.00 6.86 512.66 21074. 0.484 0.117 0.00 7.01 512.81 21535. 0.494 0.121 0.00 7.16 512.96 21996. 0.505 0.124 0.00 7.30 513.10 22426. 0.515 0.128 0.00 7.45 513.25 22886. 0.525 0.131 0.00 7.50 513.30 23040. 0.529 0.132 0.00 7.60 513.40 23347. 0.536 0.442 0.00 7.70 513.50 23654. 0.543 1.010 0.00 7.80 513.60 23962. 0.550 1.740 0.00 7.90 513.70 24269. 0.557 2.530 0.00 8.00 513.80 24576. 0.564 2.820 0.00 8.10 513.90 24883. 0.571 3.070 0.00 8.20 514.00 25190. 0.578 3.310 0.00 8.30 514.10 25498. 0.585 3.530 0.00 8.40 514.20 25805. 0.592 3.740 0.00 8.50 514.30 26112. 0.599 3.930 0.00 Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 0.68 0.50 7.61 513.41 23378. 0.537 2 0.45 0.12 7.02 512.82 21558. 0.495 3 0.43 0.02 2.70 508.50 8309. 0.191 4 0.37 0.12 6.95 512.75 21347. 0.490 5 0.37 0.05 3.97 509.77 12209. 0.280 6 0.37 0.02 1.55 507.35 4759. 0.109 7 0.35 0.02 1.86 507.66 5708. 0.131 8 0.22 0.02 1.26 507.06 3863. 0.089 Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.50 0.13 ******** 0.25 0.57 2 0.12 0.08 ******** ******* 0.17 3 0.02 0.06 ******** ******* 0.08 4 0.12 0.07 ******** ******* 0.16 5 0.05 0.05 ******** ******* 0.06 6 0.02 0.04 ******** ******* 0.05 7 0.02 0.05 ******** ******* 0.06 8 0.02 0.03 ******** ******* 0.03 ---------------------------------- Route Time Series through Facility Inflow Time Series File:west-dev.tsf Outflow Time Series File:West-RDOut POC Time Series File:West-DSOut Weston Heights North Technical Information Report Inflow/Outflow Analysis Peak Inflow Discharge: 0.683 CFS at 7:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.499 CFS at 9:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.61 Ft Peak Reservoir Elev: 513.41 Ft Peak Reservoir Storage: 23378. Cu-Ft : 0.537 Ac-Ft Add Time Series:west-byp.tsf Peak Summed Discharge: 0.573 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:West-DSOut.tsf Duration Comparison Anaylsis Base File: west-pre.tsf New File: west-dsout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New %Change Probability Base New %Change 0.047 | 0.91E-02 0.88E-02 -3.2 | 0.91E-02 0.047 0.046 -1.9 0.057 | 0.60E-02 0.61E-02 3.3 | 0.60E-02 0.057 0.059 2.0 0.068 | 0.39E-02 0.42E-02 7.9 | 0.39E-02 0.068 0.069 1.8 0.079 | 0.26E-02 0.26E-02 -1.3 | 0.26E-02 0.079 0.078 -0.2 0.089 | 0.16E-02 0.17E-02 4.0 | 0.16E-02 0.089 0.092 3.0 0.100 | 0.11E-02 0.13E-02 14.3 | 0.11E-02 0.100 0.106 6.3 0.110 | 0.88E-03 0.98E-03 11.1 | 0.88E-03 0.110 0.114 3.0 0.121 | 0.68E-03 0.65E-03 -4.8 | 0.68E-03 0.121 0.121 -0.3 0.132 | 0.47E-03 0.42E-03 -10.3 | 0.47E-03 0.132 0.130 -1.0 0.142 | 0.31E-03 0.24E-03 -21.1 | 0.31E-03 0.142 0.139 -2.6 0.153 | 0.15E-03 0.82E-04 -44.4 | 0.15E-03 0.153 0.147 -3.7 0.164 | 0.98E-04 0.16E-04 -83.3 | 0.98E-04 0.164 0.152 -7.1 0.174 | 0.49E-04 0.00E+00 -100.0 | 0.49E-04 0.174 0.154 -11.6 0.185 | 0.16E-04 0.00E+00 -100.0 | 0.16E-04 0.185 0.165 -10.8 Maximum positive excursion = 0.007 cfs ( 7.0%) occurring at 0.099 cfs on the Base Data:west-pre.tsf and at 0.106 cfs on the New Data:west-dsout.tsf Maximum negative excursion = 0.029 cfs (-15.6%) occurring at 0.182 cfs on the Base Data:west-pre.tsf and at 0.154 cfs on the New Data:west-dsout.tsf Weston Heights 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*(0.73 AC)DateProject No.DrawnDesignSheet:JDAEWJ6/9/16349-007-15EXISTING WETLANDHYDROPERIODWESTON HEIGHTS NORTH NEXISTING WETLAND HYDROPERIOD BASINLEGEND NE 7TH PLNILE AVE NEUNDISTURBEDWETLANDAREA*(0.73 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_160620 Site Name: Weston Heights Site Address: Nile Ave City : Renton Report Date: 6/20/2016 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.17 Version : 2015/02/16 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Wetland Basin Bypass: No GroundWater: No Pervious Land Use Acres C, Forest, Mod 2.39 C, Lawn, Flat 1.64 Pervious Total 4.03 Impervious Land Use Acres ROADS FLAT 0.12 Impervious Total 0.12 Basin Total 4.15 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Weston Heights North Technical Information Report Bypass: No GroundWater: No Pervious Land Use Acres C, Forest, Mod 2.92 C, Lawn, Flat .95 Pervious Total 3.87 Impervious Land Use Acres ROADS FLAT 0.2 Impervious Total 0.2 Basin Total 4.07 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.03 Total Impervious Area:0.12 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:3.87 Total Impervious Area:0.2 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.351893 5 year 0.569109 10 year 0.735628 25 year 0.971152 50 year 1.164627 100 year 1.373454 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.315674 5 year 0.49345 Weston Heights North Technical Information Report 10 year 0.629438 25 year 0.822191 50 year 0.981174 100 year 1.15354 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.614 0.527 1950 0.629 0.517 1951 0.409 0.392 1952 0.195 0.194 1953 0.142 0.147 1954 0.287 0.258 1955 0.301 0.286 1956 0.342 0.310 1957 0.425 0.372 1958 0.220 0.208 1959 0.199 0.197 1960 0.435 0.404 1961 0.323 0.285 1962 0.125 0.130 1963 0.331 0.287 1964 0.311 0.285 1965 0.407 0.345 1966 0.221 0.208 1967 0.637 0.526 1968 0.359 0.323 1969 0.380 0.305 1970 0.320 0.289 1971 0.408 0.351 1972 0.599 0.487 1973 0.175 0.178 1974 0.378 0.334 1975 0.451 0.401 1976 0.308 0.285 1977 0.273 0.223 1978 0.282 0.251 1979 0.176 0.189 1980 0.795 0.711 1981 0.309 0.273 1982 0.706 0.594 1983 0.313 0.265 1984 0.228 0.204 1985 0.264 0.220 1986 0.395 0.370 1987 0.380 0.362 1988 0.144 0.145 1989 0.127 0.126 1990 1.388 1.205 1991 0.877 0.729 1992 0.265 0.249 1993 0.174 0.174 1994 0.112 0.112 1995 0.260 0.246 1996 0.679 0.618 Weston Heights North Technical Information Report 1997 0.439 0.402 1998 0.302 0.270 1999 0.983 0.837 2000 0.347 0.303 2001 0.171 0.165 2002 0.549 0.447 2003 0.540 0.484 2004 0.687 0.556 2005 0.365 0.328 2006 0.366 0.327 2007 1.216 1.027 2008 0.847 0.782 2009 0.521 0.460 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.3883 1.2045 2 1.2158 1.0265 3 0.9831 0.8370 4 0.8765 0.7816 5 0.8468 0.7290 6 0.7946 0.7107 7 0.7063 0.6179 8 0.6873 0.5937 9 0.6787 0.5561 10 0.6366 0.5270 11 0.6295 0.5258 12 0.6138 0.5170 13 0.5993 0.4865 14 0.5495 0.4845 15 0.5404 0.4603 16 0.5214 0.4471 17 0.4510 0.4036 18 0.4390 0.4021 19 0.4346 0.4011 20 0.4248 0.3917 21 0.4094 0.3721 22 0.4084 0.3700 23 0.4070 0.3623 24 0.3951 0.3514 25 0.3801 0.3446 26 0.3798 0.3341 27 0.3785 0.3283 28 0.3662 0.3269 29 0.3649 0.3228 30 0.3593 0.3100 31 0.3474 0.3054 32 0.3423 0.3034 33 0.3310 0.2887 34 0.3231 0.2873 35 0.3203 0.2857 36 0.3129 0.2855 37 0.3109 0.2852 38 0.3089 0.2850 39 0.3079 0.2728 Weston Heights North Technical Information Report 40 0.3019 0.2696 41 0.3011 0.2653 42 0.2871 0.2585 43 0.2820 0.2507 44 0.2735 0.2493 45 0.2654 0.2457 46 0.2641 0.2235 47 0.2596 0.2199 48 0.2278 0.2084 49 0.2211 0.2077 50 0.2198 0.2045 51 0.1993 0.1971 52 0.1955 0.1942 53 0.1761 0.1886 54 0.1753 0.1785 55 0.1738 0.1737 56 0.1706 0.1654 57 0.1439 0.1470 58 0.1423 0.1449 59 0.1272 0.1299 60 0.1254 0.1256 61 0.1125 0.1119 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.1759 4179 3696 88 Pass 0.1859 3478 3050 87 Pass 0.1959 2920 2543 87 Pass 0.2059 2464 2126 86 Pass 0.2159 2087 1786 85 Pass 0.2259 1779 1522 85 Pass 0.2359 1519 1292 85 Pass 0.2459 1303 1124 86 Pass 0.2558 1145 955 83 Pass 0.2658 988 811 82 Pass 0.2758 847 670 79 Pass 0.2858 708 554 78 Pass 0.2958 595 458 76 Pass 0.3058 496 383 77 Pass 0.3158 406 317 78 Pass 0.3257 340 267 78 Pass 0.3357 294 235 79 Pass 0.3457 263 208 79 Pass 0.3557 233 179 76 Pass 0.3657 207 157 75 Pass 0.3757 178 130 73 Pass 0.3857 159 114 71 Pass 0.3957 147 105 71 Pass 0.4056 133 92 69 Pass 0.4156 126 84 66 Pass 0.4256 116 78 67 Pass Weston Heights North Technical Information Report 0.4356 105 72 68 Pass 0.4456 96 69 71 Pass 0.4556 89 61 68 Pass 0.4656 86 57 66 Pass 0.4755 81 52 64 Pass 0.4855 75 47 62 Pass 0.4955 72 44 61 Pass 0.5055 68 43 63 Pass 0.5155 65 37 56 Pass 0.5255 62 32 51 Pass 0.5355 59 27 45 Pass 0.5455 56 25 44 Pass 0.5554 50 22 44 Pass 0.5654 48 19 39 Pass 0.5754 46 19 41 Pass 0.5854 43 19 44 Pass 0.5954 41 18 43 Pass 0.6054 38 16 42 Pass 0.6154 32 14 43 Pass 0.6253 32 13 40 Pass 0.6353 29 12 41 Pass 0.6453 28 12 42 Pass 0.6553 27 12 44 Pass 0.6653 25 12 48 Pass 0.6753 23 12 52 Pass 0.6853 20 12 60 Pass 0.6953 18 11 61 Pass 0.7052 17 10 58 Pass 0.7152 14 9 64 Pass 0.7252 14 8 57 Pass 0.7352 14 6 42 Pass 0.7452 14 6 42 Pass 0.7552 12 6 50 Pass 0.7652 12 6 50 Pass 0.7751 12 6 50 Pass 0.7851 12 5 41 Pass 0.7951 11 5 45 Pass 0.8051 11 5 45 Pass 0.8151 10 5 50 Pass 0.8251 9 5 55 Pass 0.8351 9 5 55 Pass 0.8451 8 4 50 Pass 0.8550 7 4 57 Pass 0.8650 6 4 66 Pass 0.8750 6 3 50 Pass 0.8850 5 2 40 Pass 0.8950 5 2 40 Pass 0.9050 5 2 40 Pass 0.9150 5 2 40 Pass 0.9249 5 2 40 Pass 0.9349 5 2 40 Pass 0.9449 5 2 40 Pass 0.9549 5 2 40 Pass 0.9649 4 2 50 Pass 0.9749 4 2 50 Pass 0.9849 3 2 66 Pass 0.9949 3 2 66 Pass Weston Heights North Technical Information Report 1.0048 3 2 66 Pass 1.0148 2 2 100 Pass 1.0248 2 2 100 Pass 1.0348 2 1 50 Pass 1.0448 2 1 50 Pass 1.0548 2 1 50 Pass 1.0648 2 1 50 Pass 1.0747 2 1 50 Pass 1.0847 2 1 50 Pass 1.0947 2 1 50 Pass 1.1047 2 1 50 Pass 1.1147 2 1 50 Pass 1.1247 2 1 50 Pass 1.1347 2 1 50 Pass 1.1447 2 1 50 Pass 1.1546 2 1 50 Pass 1.1646 2 1 50 Pass _____________________________________________________ ___________________________________________________________________ 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 83.5601 81.1757 97.1 Pass Feb 63.2200 61.9983 98.1 Pass Mar 54.1575 53.3265 98.5 Pass Apr 33.8289 33.5882 99.3 Pass May 18.5240 18.5470 100.1 Pass Jun 14.2424 14.0530 98.7 Pass Jul 9.8981 9.9685 100.7 Pass Aug 9.1697 8.9979 98.1 Pass Sep 9.0665 8.7515 96.5 Pass Oct 17.9055 15.9391 89.0 Pass Nov 53.2741 48.3177 90.7 Pass Dec 75.5175 72.0532 95.4 Pass Day Predevel Mitigated Percent Pass/Fail Jan1 2.7430 2.6643 97.1 Pass 2 2.7092 2.5986 95.9 Pass 3 2.5126 2.4375 97.0 Pass 4 2.8627 2.7765 97.0 Pass 5 2.9059 2.8080 96.6 Pass 6 3.0584 2.9589 96.7 Pass 7 2.8224 2.7223 96.5 Pass 8 2.8327 2.7288 96.3 Pass 9 2.4328 2.3682 97.3 Pass 10 2.2725 2.2093 97.2 Pass 11 2.4503 2.3831 97.3 Pass Weston Heights North Technical Information Report 12 2.5436 2.4861 97.7 Pass 13 3.0111 2.9334 97.4 Pass 14 3.0505 2.9483 96.7 Pass 15 2.7660 2.6816 97.0 Pass 16 2.7902 2.7055 97.0 Pass 17 2.7323 2.6607 97.4 Pass 18 2.9999 2.9140 97.1 Pass 19 2.8991 2.8179 97.2 Pass 20 2.6959 2.6181 97.1 Pass 21 2.4794 2.4166 97.5 Pass 22 2.6825 2.6197 97.7 Pass 23 3.0014 2.9147 97.1 Pass 24 2.7711 2.6786 96.7 Pass 25 2.4305 2.3665 97.4 Pass 26 2.4197 2.3646 97.7 Pass 27 2.3875 2.3389 98.0 Pass 28 2.5203 2.4719 98.1 Pass 29 2.7496 2.6787 97.4 Pass 30 2.6812 2.6267 98.0 Pass 31 2.6590 2.5872 97.3 Pass Feb1 2.4262 2.3712 97.7 Pass 2 2.1887 2.1391 97.7 Pass 3 2.1662 2.1251 98.1 Pass 4 1.8991 1.8707 98.5 Pass 5 2.0356 2.0183 99.2 Pass 6 2.1972 2.1606 98.3 Pass 7 2.6078 2.5631 98.3 Pass 8 2.6145 2.5569 97.8 Pass 9 2.2087 2.1694 98.2 Pass 10 1.9356 1.9083 98.6 Pass 11 2.1449 2.1162 98.7 Pass 12 2.2049 2.1563 97.8 Pass 13 2.0175 1.9793 98.1 Pass 14 2.1635 2.1316 98.5 Pass 15 2.3941 2.3384 97.7 Pass 16 2.3948 2.3424 97.8 Pass 17 2.3224 2.2794 98.2 Pass 18 2.7174 2.6509 97.6 Pass 19 2.4868 2.4188 97.3 Pass 20 2.2243 2.1845 98.2 Pass 21 2.0803 2.0426 98.2 Pass 22 2.0157 1.9850 98.5 Pass 23 2.1781 2.1373 98.1 Pass 24 2.1322 2.0898 98.0 Pass 25 1.9896 1.9492 98.0 Pass 26 2.1143 2.0713 98.0 Pass 27 2.1150 2.0803 98.4 Pass 28 2.2285 2.1921 98.4 Pass 29 1.9059 1.8766 98.5 Pass Mar1 1.8695 1.8381 98.3 Pass 2 2.1162 2.0762 98.1 Pass 3 2.1276 2.0848 98.0 Pass 4 2.2343 2.1919 98.1 Pass 5 1.8870 1.8516 98.1 Pass 6 1.7340 1.7125 98.8 Pass 7 1.6571 1.6501 99.6 Pass 8 1.9223 1.8954 98.6 Pass Weston Heights North Technical Information Report 9 1.9731 1.9343 98.0 Pass 10 1.9524 1.9231 98.5 Pass 11 2.1620 2.1253 98.3 Pass 12 1.9730 1.9280 97.7 Pass 13 1.8341 1.7998 98.1 Pass 14 1.8731 1.8447 98.5 Pass 15 1.7426 1.7154 98.4 Pass 16 1.7716 1.7406 98.3 Pass 17 1.7369 1.7172 98.9 Pass 18 1.6771 1.6474 98.2 Pass 19 1.5238 1.5034 98.7 Pass 20 1.3688 1.3525 98.8 Pass 21 1.5437 1.5426 99.9 Pass 22 1.7103 1.6927 99.0 Pass 23 1.6897 1.6644 98.5 Pass 24 1.6292 1.5967 98.0 Pass 25 1.5146 1.4861 98.1 Pass 26 1.4484 1.4263 98.5 Pass 27 1.3629 1.3488 99.0 Pass 28 1.4321 1.4169 98.9 Pass 29 1.4413 1.4207 98.6 Pass 30 1.3416 1.3222 98.6 Pass 31 1.2912 1.2780 99.0 Pass Apr1 1.2031 1.1949 99.3 Pass 2 1.2292 1.2166 99.0 Pass 3 1.4703 1.4614 99.4 Pass 4 1.5932 1.5713 98.6 Pass 5 1.4277 1.4099 98.8 Pass 6 1.2210 1.2073 98.9 Pass 7 1.2380 1.2325 99.6 Pass 8 1.3309 1.3198 99.2 Pass 9 1.2034 1.1901 98.9 Pass 10 1.1577 1.1487 99.2 Pass 11 1.1392 1.1286 99.1 Pass 12 1.1922 1.1869 99.6 Pass 13 1.1368 1.1288 99.3 Pass 14 1.0513 1.0477 99.7 Pass 15 1.2047 1.1999 99.6 Pass 16 1.2644 1.2431 98.3 Pass 17 0.9998 0.9889 98.9 Pass 18 1.1756 1.1775 100.2 Pass 19 1.2570 1.2269 97.6 Pass 20 0.9942 0.9811 98.7 Pass 21 0.9451 0.9491 100.4 Pass 22 1.1374 1.1330 99.6 Pass 23 0.9987 0.9922 99.3 Pass 24 0.8788 0.8739 99.4 Pass 25 0.7714 0.7729 100.2 Pass 26 0.8072 0.8173 101.3 Pass 27 0.7815 0.7819 100.1 Pass 28 0.8216 0.8284 100.8 Pass 29 0.9064 0.9004 99.3 Pass 30 0.8834 0.8755 99.1 Pass May1 0.8146 0.8052 98.8 Pass 2 0.7234 0.7197 99.5 Pass 3 0.7039 0.7094 100.8 Pass 4 0.7335 0.7344 100.1 Pass Weston Heights North Technical Information Report 5 0.7237 0.7266 100.4 Pass 6 0.6674 0.6687 100.2 Pass 7 0.6067 0.6091 100.4 Pass 8 0.5894 0.5923 100.5 Pass 9 0.5948 0.5974 100.5 Pass 10 0.6170 0.6282 101.8 Pass 11 0.5564 0.5636 101.3 Pass 12 0.5951 0.5992 100.7 Pass 13 0.6041 0.6102 101.0 Pass 14 0.5836 0.5848 100.2 Pass 15 0.5778 0.5739 99.3 Pass 16 0.5337 0.5375 100.7 Pass 17 0.5369 0.5442 101.4 Pass 18 0.5724 0.5817 101.6 Pass 19 0.5710 0.5698 99.8 Pass 20 0.5182 0.5205 100.4 Pass 21 0.5125 0.5140 100.3 Pass 22 0.5033 0.5132 102.0 Pass 23 0.4946 0.5030 101.7 Pass 24 0.4706 0.4735 100.6 Pass 25 0.4739 0.4893 103.3 Pass 26 0.4951 0.4913 99.2 Pass 27 0.5079 0.5009 98.6 Pass 28 0.5618 0.5506 98.0 Pass 29 0.5996 0.5854 97.6 Pass 30 0.5979 0.5744 96.1 Pass 31 0.5806 0.5568 95.9 Pass Jun1 0.6004 0.5750 95.8 Pass 2 0.5982 0.5869 98.1 Pass 3 0.5865 0.5757 98.2 Pass 4 0.5109 0.5014 98.2 Pass 5 0.5241 0.5244 100.0 Pass 6 0.6303 0.6033 95.7 Pass 7 0.5774 0.5571 96.5 Pass 8 0.5766 0.5618 97.4 Pass 9 0.5866 0.5712 97.4 Pass 10 0.5274 0.5198 98.6 Pass 11 0.5057 0.4973 98.3 Pass 12 0.4584 0.4474 97.6 Pass 13 0.4170 0.4152 99.6 Pass 14 0.4063 0.4117 101.3 Pass 15 0.4152 0.4199 101.1 Pass 16 0.4373 0.4446 101.7 Pass 17 0.4199 0.4185 99.7 Pass 18 0.3956 0.3995 101.0 Pass 19 0.3964 0.4042 102.0 Pass 20 0.4374 0.4312 98.6 Pass 21 0.4318 0.4183 96.9 Pass 22 0.4067 0.4045 99.5 Pass 23 0.4853 0.4870 100.4 Pass 24 0.4480 0.4283 95.6 Pass 25 0.3991 0.3916 98.1 Pass 26 0.3748 0.3759 100.3 Pass 27 0.3709 0.3771 101.7 Pass 28 0.3681 0.3728 101.3 Pass 29 0.3693 0.3742 101.3 Pass 30 0.3923 0.3915 99.8 Pass Weston Heights North Technical Information Report Jul1 0.3715 0.3713 100.0 Pass 2 0.3610 0.3617 100.2 Pass 3 0.3479 0.3484 100.1 Pass 4 0.3485 0.3536 101.5 Pass 5 0.3339 0.3357 100.5 Pass 6 0.3323 0.3391 102.0 Pass 7 0.3402 0.3462 101.7 Pass 8 0.3416 0.3494 102.3 Pass 9 0.3339 0.3375 101.1 Pass 10 0.3199 0.3213 100.4 Pass 11 0.3344 0.3419 102.2 Pass 12 0.3449 0.3426 99.3 Pass 13 0.3392 0.3378 99.6 Pass 14 0.3227 0.3172 98.3 Pass 15 0.3399 0.3496 102.8 Pass 16 0.3213 0.3198 99.5 Pass 17 0.3107 0.3094 99.6 Pass 18 0.3072 0.3102 101.0 Pass 19 0.3010 0.3039 101.0 Pass 20 0.2948 0.2969 100.7 Pass 21 0.2980 0.3018 101.3 Pass 22 0.2921 0.2946 100.8 Pass 23 0.2869 0.2885 100.6 Pass 24 0.2856 0.2881 100.9 Pass 25 0.2988 0.3085 103.3 Pass 26 0.2873 0.2885 100.4 Pass 27 0.2835 0.2850 100.5 Pass 28 0.2769 0.2772 100.1 Pass 29 0.2751 0.2764 100.5 Pass 30 0.2745 0.2749 100.1 Pass 31 0.2818 0.2845 101.0 Pass Aug1 0.2813 0.2865 101.9 Pass 2 0.3049 0.3023 99.2 Pass 3 0.2855 0.2832 99.2 Pass 4 0.2758 0.2721 98.7 Pass 5 0.2902 0.2931 101.0 Pass 6 0.2885 0.2931 101.6 Pass 7 0.2744 0.2696 98.3 Pass 8 0.2818 0.2852 101.2 Pass 9 0.2690 0.2659 98.9 Pass 10 0.2651 0.2661 100.4 Pass 11 0.2607 0.2625 100.7 Pass 12 0.2557 0.2567 100.4 Pass 13 0.2935 0.2952 100.6 Pass 14 0.3247 0.3152 97.1 Pass 15 0.2920 0.2804 96.0 Pass 16 0.2925 0.2839 97.1 Pass 17 0.3120 0.3057 98.0 Pass 18 0.2945 0.2916 99.0 Pass 19 0.2755 0.2694 97.8 Pass 20 0.2755 0.2788 101.2 Pass 21 0.2855 0.2917 102.2 Pass 22 0.3410 0.3379 99.1 Pass 23 0.3444 0.3251 94.4 Pass 24 0.3414 0.3154 92.4 Pass 25 0.3505 0.3252 92.8 Pass 26 0.3272 0.3126 95.5 Pass Weston Heights North Technical Information Report 27 0.2986 0.2873 96.2 Pass 28 0.3044 0.2958 97.2 Pass 29 0.3133 0.2894 92.4 Pass 30 0.2885 0.2765 95.8 Pass 31 0.2829 0.2780 98.3 Pass Sep1 0.2818 0.2790 99.0 Pass 2 0.2649 0.2624 99.1 Pass 3 0.2810 0.2812 100.1 Pass 4 0.2587 0.2548 98.5 Pass 5 0.2713 0.2732 100.7 Pass 6 0.2465 0.2403 97.5 Pass 7 0.2661 0.2681 100.8 Pass 8 0.2659 0.2590 97.4 Pass 9 0.2721 0.2776 102.0 Pass 10 0.2597 0.2587 99.6 Pass 11 0.2652 0.2517 94.9 Pass 12 0.2525 0.2482 98.3 Pass 13 0.2644 0.2729 103.2 Pass 14 0.2478 0.2498 100.8 Pass 15 0.2569 0.2596 101.1 Pass 16 0.3463 0.3530 101.9 Pass 17 0.3285 0.3058 93.1 Pass 18 0.3278 0.3124 95.3 Pass 19 0.3146 0.2995 95.2 Pass 20 0.3152 0.2932 93.0 Pass 21 0.3942 0.3699 93.8 Pass 22 0.4552 0.4013 88.1 Pass 23 0.3714 0.3427 92.3 Pass 24 0.3180 0.3042 95.7 Pass 25 0.3202 0.3039 94.9 Pass 26 0.3047 0.2947 96.7 Pass 27 0.3497 0.3219 92.1 Pass 28 0.3116 0.2886 92.6 Pass 29 0.3716 0.3458 93.1 Pass 30 0.3468 0.3104 89.5 Pass Oct1 0.3370 0.3063 90.9 Pass 2 0.3294 0.3138 95.3 Pass 3 0.3590 0.3458 96.3 Pass 4 0.3794 0.3421 90.2 Pass 5 0.6622 0.6204 93.7 Pass 6 0.5517 0.5087 92.2 Pass 7 0.5764 0.5408 93.8 Pass 8 0.6355 0.5585 87.9 Pass 9 0.6238 0.5478 87.8 Pass 10 0.4975 0.4247 85.4 Pass 11 0.3969 0.3623 91.3 Pass 12 0.3829 0.3580 93.5 Pass 13 0.3533 0.3388 95.9 Pass 14 0.3660 0.3376 92.2 Pass 15 0.3655 0.3410 93.3 Pass 16 0.4480 0.4164 92.9 Pass 17 0.5083 0.4466 87.8 Pass 18 0.5993 0.5233 87.3 Pass 19 0.9120 0.8099 88.8 Pass 20 0.9762 0.8541 87.5 Pass 21 0.7848 0.6812 86.8 Pass 22 0.6761 0.5813 86.0 Pass Weston Heights North Technical Information Report 23 0.6093 0.5295 86.9 Pass 24 0.5887 0.5207 88.4 Pass 25 0.6908 0.5930 85.8 Pass 26 0.7488 0.6500 86.8 Pass 27 0.7848 0.6589 84.0 Pass 28 0.8381 0.7175 85.6 Pass 29 0.8031 0.7055 87.9 Pass 30 0.7731 0.6946 89.9 Pass 31 0.7833 0.6914 88.3 Pass Nov1 0.8828 0.7857 89.0 Pass 2 1.1326 0.9944 87.8 Pass 3 1.3244 1.1153 84.2 Pass 4 1.1448 0.9420 82.3 Pass 5 1.3206 1.1512 87.2 Pass 6 1.3471 1.1707 86.9 Pass 7 1.1443 0.9954 87.0 Pass 8 1.2744 1.1282 88.5 Pass 9 1.4212 1.2599 88.7 Pass 10 1.6837 1.5118 89.8 Pass 11 1.8512 1.6329 88.2 Pass 12 1.7836 1.5742 88.3 Pass 13 1.8537 1.6301 87.9 Pass 14 1.5832 1.4099 89.1 Pass 15 1.5666 1.4126 90.2 Pass 16 1.6178 1.4563 90.0 Pass 17 1.6998 1.5292 90.0 Pass 18 2.0576 1.9137 93.0 Pass 19 2.3915 2.1987 91.9 Pass 20 2.2344 2.0422 91.4 Pass 21 1.9792 1.8217 92.0 Pass 22 2.0826 1.9581 94.0 Pass 23 2.9019 2.7009 93.1 Pass 24 2.9612 2.7767 93.8 Pass 25 2.6232 2.4399 93.0 Pass 26 2.3597 2.1817 92.5 Pass 27 1.9725 1.8363 93.1 Pass 28 2.0196 1.9026 94.2 Pass 29 2.2769 2.1554 94.7 Pass 30 2.1939 2.0558 93.7 Pass Dec1 2.3079 2.1579 93.5 Pass 2 2.8916 2.7240 94.2 Pass 3 2.6311 2.4734 94.0 Pass 4 2.3432 2.2272 95.0 Pass 5 2.3360 2.1986 94.1 Pass 6 2.0890 1.9747 94.5 Pass 7 2.0435 1.9384 94.9 Pass 8 2.1148 2.0201 95.5 Pass 9 2.3573 2.2491 95.4 Pass 10 2.4178 2.3043 95.3 Pass 11 2.5444 2.4170 95.0 Pass 12 2.5694 2.4384 94.9 Pass 13 2.6401 2.5049 94.9 Pass 14 3.0557 2.9191 95.5 Pass 15 2.7431 2.6161 95.4 Pass 16 2.4663 2.3424 95.0 Pass 17 2.2397 2.1386 95.5 Pass 18 2.0809 2.0000 96.1 Pass Weston Heights North Technical Information Report 19 2.4036 2.3202 96.5 Pass 20 2.4839 2.3718 95.5 Pass 21 2.3052 2.2028 95.6 Pass 22 2.3251 2.2324 96.0 Pass 23 2.2466 2.1538 95.9 Pass 24 2.1462 2.0786 96.8 Pass 25 2.5632 2.4811 96.8 Pass 26 2.9059 2.7930 96.1 Pass 27 2.3743 2.2766 95.9 Pass 28 2.3438 2.2851 97.5 Pass 29 2.9308 2.8246 96.4 Pass 30 2.4225 2.3333 96.3 Pass 31 2.3459 2.2772 97.1 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. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2016; All Rights Reserved. Weston Heights North Technical Information Report WWHM2012 – Fluctuation Analysis 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 one new catch basin tying into an existing conveyance system running along NE 7th Pl contributing to the Olympus Villa Pond, as well as tying an existing french drain into an existing conveyance system leading 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. The project also proposes to tie an existing french drain, located in Lot 1, to the existing conveyance system leading out of the Olympus Villa Pond. As this french drain will be contributory to an existing conveyance line, analysis will be performed to ensure capacity from this french drain and the additional area routed out of 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 with KCRTS using 15-minute timesteps. The KCSWDM also requires that the 25-year peak design flows be contained within the conveyance system with no surcharge. The 100-year peak design flows must also be analyzed, and it must be demonstrated that any surcharge during the 100-year peak design event must not cause or aggravate a flooding problem. Systems downstream of the proposed detention systems have not been included as the release rates are a reduction of the flows entering the facilities. Conveyance calculations for 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 UPDATE CONVEYANCE CALCUATIONS TO ACCOUNT FOR NEW CATCH BASINS ALONG THE SOUTHERN FRONTAGE OF NE 7TH PLACE. BASIN #4BASIN #10BASIN #8BASIN #5PRIVATE ROAD CTRACT ATRACT CTRACT BBASIN #17BASIN #11VAULTBASINBASIN #5BASIN#5ABASIN #12BASIN #15BASIN #16DateProject No.DrawnDesignSheet:JDAJDA7/8/16349-007-15DEVELOPEDCONVEYANCEWESTON HEIGHTS NORTHNNAMEBASINAREAIMERVIOUSAREALAWNAREATOTALWESTON HEIGHTS NORTH BASIN AREAS Weston Heights North Technical Information Report Weston Heights North Layout WN1 Weston Heights North Technical Information Report Appended on: Tuesday, July 05, 2016 11:18:43 AM ROUTEHYD [] THRU [LayoutWN1] USING [100 year] AND [TYPE1A.RAC] NOTZERO RELATIVE SCS/SBUH Gravity Analysis using 24 hr duration storm Reach ID Area (ac) Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Depth ratio Size nVel (ft/s) fVel (ft/s) Infil Vol (cf) CBasin / Hyd EX-P4 0.24 0.2447 5.7122 0.0428 0.1412 0.1412 12 in Diam 3.6161 7.2729 0.00 BASIN-12 EX-P5 0.49 0.4939 4.3614 0.1133 0.2277 0.2277 12 in Diam 3.6718 5.5531 0.00 BASIN-11 WN- P1 0.34 0.2932 2.7366 0.1071 0.2204 0.2204 12 in Diam 2.2832 3.4843 0.00 BASIN- 15;BASIN- 16 EX-P1 0.41 0.3625 4.3614 0.0831 0.1946 0.1946 12 in Diam 3.3704 5.5531 0.00 BASIN-08 EX-P2 0.45 0.4038 5.5004 0.0734 0.1833 0.1833 12 in Diam 4.0931 7.0034 0.00 BASIN-10 EX-P3 1.02 0.9774 3.0801 0.3173 0.3852 0.3852 12 in Diam 3.5037 3.9217 0.00 BASIN-4 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 510.985 EX-CB3 EX- OVP_IN 514.4402 ------ 0.2467 0.1010 514.7878 517.9100 EX-CB5 EX-CB3 515.4127 ------ 0.0088 ------ 515.4216 519.1100 EX-CB4 EX-CB5 519.5541 ------ ------ ------ 519.5541 523.3400 EX-CB2 EX-CB3 515.4381 ------ 0.2450 ------ 515.6831 518.3900 EX-CB1 EX-CB2 515.8602 0.0809 0.0970 ------ 515.8763 518.3500 WN-CB1 EX-CB1 515.9701 ------ ------ ------ 515.9701 518.1700 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment EX-P3 0.5802 0.5802 0.98 0.4151 0.4151 0.3852 SuperCrit flow, Inlet end controls EX-P5 0.3927 0.3927 0.49 0.9278 0.2914 0.2277 SuperCrit flow, Inlet end controls EX-P4 0.2641 0.2641 0.24 0.5016 0.2031 0.1412 SuperCrit flow, Inlet end controls EX-P2 0.3481 0.3481 0.40 0.9278 0.2627 0.1833 SuperCrit flow, Inlet end controls EX-P1 0.4602 0.4602 0.36 0.5931 0.2485 0.1946 Outlet Control M1 Weston Heights North Technical Information Report Backwater WN- P1 0.3401 0.3401 0.29 0.4763 0.2230 0.2204 Outlet Control M1 Backwater Licensed to: Engenious Systems, Inc. Weston Heights North Technical Information Report Appended on: Tuesday, July 05, 2016 11:21:45 AM 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 Record Id: EX-P2 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX-CB3 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 Weston Heights North Technical Information Report 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-CB3 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 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-P4 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX-CB5 UpNode EX-CB4 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 200.60 ft Slope 2.18% Up Invert 519.29 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: EX-P5 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX-CB3 UpNode EX-CB5 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 91.40 ft Slope 1.27% Up Invert 515.02 ft Dn Invert 513.86 ft Weston Heights North Technical Information Report 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-P1 Section Shape: Circular Uniform Flow Method: Manning's Coefficient: 0.012 Routing Method: Travel Time Shift Contributing Hyd DnNode EX-CB1 UpNode WN-CB1 Material unspecified Size 12 in Diam Ent Losses Groove End w/Headwall Length 46.00 ft Slope 0.50% Up Invert 515.63 ft Dn Invert 515.40 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Node Records Record Id: 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 Weston Heights North Technical Information Report Record Id: EX-CB3 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: EX-CB4 Descrip: TYPE 1 Increment 0.10 ft Start El. 519.24 ft Max El. 523.34 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-CB5 Descrip: TYPE 1 Increment 0.10 ft Start El. 514.92 ft Max El. 519.11 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 Record Id: WN-CB1 Descrip: TYPE 1 Increment 0.10 ft Start El. 515.63 ft Max El. 518.17 ft Void Ratio 100.00 Weston Heights North Technical Information Report Condition Proposed Structure Type CB-TYPE 1 Channelization No Special Shape Catch 0.00 ft Bottom Area 3.97 sf MH/CB Type Node 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 0.01 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 0.06 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-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 0.00 DC CN 98.00 Weston Heights North Technical Information Report Pervious TC 0.00 min DC 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 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 0.03 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 0.22 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-12 Weston Heights North Technical Information Report Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.01 ac DCIA 0.23 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 0.00 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 0.23 ac 98.00 DC Composited CN (AMC 2) 98.00 Record Id: BASIN-15 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 0.10 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 0.10 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 Weston Heights North Technical Information Report 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 Record Id: BASIN-16 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 0.10 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 0.10 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 Record Id: BASIN-4 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Weston Heights North Technical Information Report 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 0.01 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 0.07 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 Weston Heights North Layout WN2 Weston Heights North Technical Information Report Appended on: Wednesday, July 06, 2016 8:57:42 AM ROUTEHYD [] THRU [LayoutWN2] USING [100 year] AND [] NOTZERO RELATIVE Fixed Flow Gravity Analysis using fixed flowrates Reach ID Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Size nVel (ft/s) fVel (ft/s) CFlow WN-P2 0.08 2.3511 0.034 0.0631 6 in Diam 5.5729 11.9742 0.08 EX-POUT 0.83 6.3001 0.1317 0.245 12 in Diam 5.5606 8.0215 0.83 EX-P6 0.91 4.9119 0.1853 0.3646 15 in Diam 3.0564 4.0025 0.00 EX-WHP2 0.91 3.2156 0.283 0.455 15 in Diam 2.2538 2.6203 0.00 EX-WHP1 1.0588 10.3604 0.1022 0.2693 15 in Diam 5.448 8.4424 0.1488 WH-P2 1.0588 2.7366 0.3869 0.432 12 in Diam 3.2585 3.4843 0.00 WH-P1 1.0588 2.7366 0.3869 0.432 12 in Diam 3.2585 3.4843 0.00 HGL Analysis From Node To Node HG El (ft)App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 505.5326 WH-CB1 DITCH_OUT 506.2586 ------ 0.0485 ------ 506.3071 510.6400 WH-CB2 WH-CB1 506.5088 0.4609 0.1531 ------ 506.2010 511.0100 EX- WHCB1 WH-CB2 509.4640 ------ 0.0007 ------ 509.4646 513.6500 No approach losses at node EX-CB6 because inverts and/or crowns are offset. EX- WHCB2 EX-WHCB1 510.0197 0.1451 0.2030 ------ 510.0776 519.6900 EX-CB6 EX-WHCB2 511.2503 ------ 0.6367 0.0373 511.9244 518.5200 EX-FD EX-CB6 516.1532 --na-- --na-- --na-- 516.1532 518.0000 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 0.6086 0.6086 1.06 0.4326 0.4326 0.4320 SuperCrit flow, Inlet end controls WH-P2 0.7988 0.7988 1.06 0.6571 0.4326 0.4320 Outlet Control M1 Backwater EX- WHP1 0.5440 0.4352 1.06 0.4910 0.4048 0.2693 SuperCrit flow, Inlet end controls EX- WHP2 0.5497 0.4397 0.91 0.5346 0.3744 0.4550 Outlet Control M1 Backwater EX-P6 0.5103 0.4083 0.91 0.3744 0.3744 0.3646 SuperCrit flow, Inlet end controls WN-P2 0.1532 0.3063 0.08 0.6844 0.1393 0.0631 SuperCrit flow, Inlet end controls Weston Heights North Technical Information Report EX- POUT 0.5181 0.5181 0.83 1.1844 0.3813 0.2450 SuperCrit flow, Inlet end controls Licensed to: SDA Engineers Weston Heights North Technical Information Report Appended on: Wednesday, July 06, 2016 8:58:51 AM Layout Report: LayoutWN2 Event Precip (in) other 2 yr 24 hr 5 year 10 year 25 year 100 year * *100 year flow rate for OVP_OUT is .83 *100 year flow rate for EX-FD is .08, see Basin 4 analysis 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 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 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-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 2.18% Up Invert 508.92 ft Dn Invert 505.71 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: 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 Weston Heights North Technical Information Report 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 0.50% Up Invert 505.71 ft Dn Invert 505.65 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Record Id: WN-P2 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 14.88% Up Invert 516.00 ft Dn Invert 511.24 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr Node Records Weston Heights North Technical Information Report 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: 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 Record Id: EX-FD Descrip: Lot 1 Ex French Drain Increment 0.10 ft Start El. 516.00 ft Max El. 518.00 ft Void Ratio 100.00 Dummy Type Node Record Id: EX-WHCB1 Descrip: 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: 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 Weston Heights North Technical Information Report MH/CB Type Node 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: 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 Record Id: WH-CB2 Descrip: TYPE 2 Increment 0.10 ft Start El. 505.71 ft Max El. 511.01 ft Void Ratio 100.00 Condition Proposed Structure Type CB-TYPE 2-48 Channelization No Special Shape Catch 0.00 ft Bottom Area 12.5664 sf MH/CB Type Node Licensed to: SDA Engineers 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 Weston Heights North Technical Information Report 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 0.07 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 Weston Heights Layout WN3 Weston Heights North Technical Information Report Appended on: Tuesday, July 05, 2016 4:11:21 PM ROUTEHYD [] THRU [LayoutWN3] USING [100 year] AND [TYPE1A.RAC] NOTZERO RELATIVE SCS/SBUH Gravity Analysis using 24 hr duration storm Reach ID Area (ac) Flow (cfs) Full Q (cfs) Full ratio nDepth (ft) Depth ratio Size nVel (ft/s) fVel (ft/s) Infil Vol (cf) CBasin / Hyd WH-- P5A 0.20 0.1948 7.3126 0.0266 0.1125 0.1125 12 in Diam 4.0091 9.3107 0.00 BASIN- 05A WH- P5 0.802 0.8094 7.052 0.1148 0.2295 0.2295 12 in Diam 5.949 8.9789 0.00 BASIN- 05 WH- P8 0.07 0.0693 7.1111 0.0097 0.0693 0.0693 12 in Diam 2.9103 9.0542 0.00 BASIN- 08 WH- P7 0.07 0.0693 7.8191 0.0089 0.0663 0.0663 12 in Diam 3.1111 9.9556 0.00 WH- P4 0.872 0.8788 15.7574 0.0558 0.1604 0.1604 12 in Diam 10.7991 20.063 0.00 BASIN- 3 HGL Analysis From Node To Node HG El (ft) App (ft) Bend (ft) Junct Loss (ft) Adjusted HG El (ft) Max El (ft) 504.8928 WH-CB4 WH-VAULT IN 510.9717 ------ 0.0474 0.0381 511.0572 513.4900 WH-CB5 WH-CB4 513.1220 ------ 0.3398 ------ 513.4618 516.4500 WH-CB5A WH-CB5 513.8045 ------ ------ ------ 513.8045 515.4600 WH-CB7 WH-CB4 513.2265 ------ 0.1468 ------ 513.3734 518.0800 WH-CB8 WH-CB7 515.8395 ------ ------ ------ 515.8395 518.7100 Conduit Notes Reach HW Depth (ft) HW/D ratio Q (cfs) TW Depth (ft) Dc (ft) Dn (ft) Comment WH-P4 0.4817 0.4817 0.88 0.3928 0.3928 0.1604 SuperCrit flow, Inlet end controls WH-P5 0.5120 0.5120 0.81 0.5672 0.3763 0.2295 SuperCrit flow, Inlet end controls WH-- P5A 0.5945 0.5945 0.19 0.8518 0.1811 0.1125 Outlet Control M1 Backwater WH-P7 0.1265 0.1265 0.07 0.5672 0.1069 0.0663 SuperCrit flow, Inlet end controls WH-P8 0.1295 0.1295 0.07 0.2734 0.1069 0.0693 SuperCrit flow, Inlet end controls Licensed to: Engenious Systems, Inc. Weston Heights North Technical Information Report Appended on: Tuesday, July 05, 2016 4:11:50 PM 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 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 Weston Heights North Technical Information Report 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 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 Weston Heights North Technical Information Report Length 92.00 ft Slope 2.84% Up Invert 515.71 ft Dn Invert 513.10 ft Conduit Constraints Min Vel Max Vel Min Slope Max Slope Min Cover 2.00 ft/s 15.00 ft/s 0.50% 2.00% 3.00 ft Drop across MH 0.00 ft Ex/Infil Rate 0.00 in/hr 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 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 Weston Heights North Technical Information Report 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 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 0.022 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 Weston Heights North Technical Information Report DCI - CN Calc Description SubArea Sub cn Impervious 0.58 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-05A Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.04 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 DCI - CN Calc Description SubArea Sub cn Impervious 0.16 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-08 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.01 ac DCIA 0.06 ac Pervious CN 86.00 DC CN 98.00 Pervious TC 5.00 min DC TC 5.00 min Weston Heights North Technical Information Report 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 0.06 ac 98.00 DC Composited CN (AMC 2) 98.00 DCI - TC Calc Type Description Length Slope Coeff Misc TT Sheet 5 min. minimum 0.00 ft 0.0% 5.0 0.00 in 5.00 min Pervious TC 5.00 min Record Id: BASIN-3 Design Method SBUH Rainfall type TYPE1A.RAC Hyd Intv 10.00 min Peaking Factor 484.00 Storm Duration 24.00 hrs Abstraction Coeff 0.20 Pervious Area 0.01 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 0.01 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 0.06 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: Engenious Systems, Inc. Weston Heights North Technical Information Report APPENDIX 5B ISOPLUVIAL MAP – 100-YR, 24-HR PRECIPITATION Project Site 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: Grading Permit - City of Renton Right-of-Way Use Permit - City of Renton Construction Stormwater Permit - WA Dept. of Ecology NO GRADING PERMIT REQUIRED 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 NE NE 7TH PLPASCO AVE NETRACT BNKDS KDS SAM SAM 6/30/16349-007-15    NW 1/4, SW 1/4 OF SECTION 11, TOWNSHIP 23 N., RANGE 5 E., W.M.WESTON HEIGHTS, LLC 15 LAKE BELLEVUE, STE 102 BELLEVUE, WA 98005 (425)869-1300 ROBERT FITZMAURICE WESTON HEIGHTS NORTH T.E.S.C. PLANC2.0 Horiz. Scale Vert. Scale Project No.Date No. Client Contact Approved By Checked By Designed By Drawn By REVISIONS DateDescriptionKnow what'sbelow.before you dig.CallR7 11 16CONSTRUCTION SEQUENCEDATUMBENCHMARKCERTIFIED EROSION CONTROL SPECIALISTNPDES PERMIT #: UPDATE AS NECESSARY KDS KDS SAM SAM 6/30/16349-007-15    NW 1/4, SW 1/4 OF SECTION 11, TOWNSHIP 23 N., RANGE 5 E., W.M.WESTON HEIGHTS, LLC 15 LAKE BELLEVUE, STE 102 BELLEVUE, WA 98005 (425)869-1300 ROBERT FITZMAURICE WESTON HEIGHTS NORTH T.E.S.C. DETAILSC2.1 Horiz. Scale Vert. Scale Project No.Date No. Client Contact Approved By Checked By Designed By Drawn By REVISIONS DateDescriptionKnow what'sbelow.before you dig.CallR7 11 16N.T.S.3-SILT FENCE DETAIL1-SEDIMENT TRAPN.T.S.N.T.S.2-PLASTIC COVERING4-FILTER FABRIC PROTECTIONN.T.S.5-INTERCEPTOR SWALEN.T.S.6-CHECK DAMSN.T.S. 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* Resident Engineer* Emergency Ecology Contact Puget Sound Office (425) 649-7000 Emergency Owner Contact* Non-Emergency Ecology Contact Northwest Region (425) 649-7000 Monitoring Personnel* * These personnel should be decided upon and included in the spaces provided at the time of, or prior to, the preconstruction meet. ESTIMATED CONSTRUCTION SCHEDULE:  Construction Start Date August 2016  Install ESC Measures August 2016  Construction End Date November 2016 CONSTRUCTION BMP LIST:  Silt Fence (BMP C233)  Storm Drain Inlet Protection (BMP C220)  Materials on Hand (BMP C150) may also be applicable  Detention Pond Or Vault  Temporary and Permanent Seeding (BMP C120)  Plastic Covering (BMP C123)  Interceptor Dike and Swale (BMP C200)  Check Dams (BMP C207) REFERENCE COR STD. PLANS !"#$ %##!&#’#% ###% %##%#!(’ $#(# 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. 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 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 1/9/2009 2009 Surface Water Design Manual – Appendix A A-30 NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Contaminants and pollution Any evidence of contaminants or pollution such as oils, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Site Life cycle System has not been inspected for three years. Facility is re-inspected and any needed maintenance performed. Sediment on vault floor Greater than 2 inches of sediment. Vault is free of sediment. Sediment on top of cartridges Greater than ½ inch of sediment. Vault is free of sediment. Vault Treatment Area Multiple scum lines above top of cartridges Thick or multiple scum lines above top of cartridges. Probably due to plugged canisters or underdrain manifold. Cause of plugging corrected, canisters replaced if necessary. Damage to wall, Frame, Bottom, and/or Top Slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or qualified inspection personnel determines the vault is not structurally sound. Vault replaced or repaired to design specifications. Vault Structure Baffles damaged Baffles corroding, cracking warping, and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specification. Standing water in vault 9 inches or greater of static water in the vault for more than 24 hours following a rain event and/or overflow occurs frequently. Probably due to plugged filter media, underdrain or outlet pipe. No standing water in vault 24 hours after a rain event. Filter Media Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and Clean-Outs Sediment/debris Underdrains or clean-outs partially plugged or filled with sediment and/or debris. Underdrains and clean-outs free of sediment and debris. Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Inlet/Outlet Pipe Damaged Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Access Manhole Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES 2009 Surface Water Design Manual – Appendix A 1/9/2009 A-31 NO. 21 – STORMFILTER (CARTRIDGE TYPE) Maintenance Component Defect or Problem Condition When Maintenance is Needed Results Expected When Maintenance is Performed Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely. Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate.