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HomeMy WebLinkAboutTIR - Approved.pdfProject R18325 Ngochan Short Plat 10/16/2020 DEVELOPMENT ENGINEERING jchavez 12/11 /2020 Ngochan Short Plat 10814 SE 173rd St Renton, WA 98055 Parcel #: 1626800010 Contact/ Owner: Doan Nguyen •FFaRR DESIepGn Farr Design LLC David Fam, PE PO BOX 94652 SEATTLE, WA 98124 daviLd@fai-i-desiollc.com 206.353.7495 �J Digitally signed UQ V I by David Farr, PE Farr, P E 020.1o.15 1151:38-07'00' Project R18325 Ngochan Short Plat 10/16/2020 TABLE OF CONTENTS 1. PROJECT OVERVIEW 2. CONDITIONS AND REQUIREMENTS SUMMARY 3. OFFSITE ANALYSIS (LEVEL 1 DOWNSTREAM ANALYSIS) Task 1: Study Area Definition and Maps Task 2: Resource Review Task 3: Field Inspection Task 4: Downstream Drainage System Description and Existing and Potential Problems 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6. SPECIAL REPORTS AND STUDIES 7. OTHER PERMITS 8. CSWPPP ANALYSIS AND DESIGN 9. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT 10. OPERATIONS AND MAINTENANCE MANUAL 3 LIST OF APPENDICES Appendix A - Stormwater Site Plans Appendix B - Operations & Maintenance Manual Appendix C - CSWPPP Appendix D -Soil logs/ Geotech Report Appendix E - Bonding Quantities Worksheet Appendix F - Declaration of Covenant Appendix G - WWHM Report LIST OF FIGURES Figure 1 TIR Worksheet................................................................................2 Figure2 Site Location.................................................................................. 7 Figure 3 Drainage Basin/Downstream Path...................................................8 Figure4 Soils................................................................................................9 Figure 5 Aerial Photograph.......................................................................... 12 Figure 6 Existing Site Conditions........................................................... ... 15 Project R18325 Ngochan Short Plat 10/16/2020 1. PROJECT OVERVIEW This Technical Information Report (TIR) is submitted in support of the permits for the Ngochan Short Plat. Two new single family homes are proposed on each lot along with a proposed driveways and a shared access driveway. This analysis was completed using the format set forth in the 2017 Renton Surface Water Design Manual (RSWDM. Figure 1 - TIR Worksheet is attached on the following page. Project Description: Please refer to Figure 2 - Vicinity Map on the following pages to aid in the project description. The Ngochan Short Plat project proposes 2 single family homes and associated infrastructure at Parcel # 162680-0010. The proposed work includes construction and grading of the site for building pads, and installation of utilities, all related to a new single family homes and a shared driveway. The proposed storm drainage system consists of 2 infiltration trenches for the future lot improvements and a single infiltration trench for the new shared driveway, and associated stormwater conveyance. The project is subject to Directed Drainage Review (2 proposed single family residences, driveways, and shared driveway with 6,843 sf of impervious) which require that all 9 Core Requirements to be addressed as well as all 6 Special Requirements. 2 Figure 1 - TIR Worksheet City of Renton TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner Doan Nguyen Phone Address 4046 S, 146th St Tukwila, WA 98168 Project Engineer Han Phan, PE Company PBC, LLC Phone 206.229.6422 Part3 TYPE OF PERMIT APPLICATION ❑ Landuse (e-g-,Subdivision f Short Subd- i UPD) ❑ Building (e-g-,MIF I Commercial l S FR) ❑ Clearing and Grading ❑ Right -of -Way Use ❑ Other Part5 PLAN AND REPORT INFORMATION Technical Information Report ❑ Full Type of Drainage Review '❑ Targeted (check one): ❑ Simplified ❑ Large Project Date (include revision ❑ Directed dates): Date of Final: Project Name NgoHan Short Plat DPERPermit # TBD Location Township 23 Range 05 Section 29 Site Address 10814 SE 173rd St Park 4 OTHER REVIEWS AND PERMITS ❑ DFVV HPA ❑ Shoreline ❑ COE 4D4 Management ❑ DOE darn Safety ❑ Structural ❑ - RockerylVaultf FEMA Floodplain ❑ ESA section 7 ❑ COE Wetlands ❑ Other Site Improvement Plan (Engr. Plans) Plan Type (check ❑ Full oney ❑ Modified ❑ Simplified Date (include revision dates): Date of Final: Part6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard f Experimental i Blanket Description: (in clLide conditions in TIR Section 2) Approved Adjustment No. Date of Approval: 3 Park 7 MONITORING REQUIREMENTS Monitoring Required: Yes No Start Date: Completion Date: Part 8 SITE COMMUNITY AND DRAINAGE BASIN Describe: Re: KCSDM Adjustment No. Community Plan : Boos Creek Special District Overlays: None Drainage Basin: Black River Stormwater Requirements: Directed Stormwater Requirerents Park 9 ONSITE AND ADJACENT SENSITIVE AREAS ❑ River/Stream ❑ Steep Slope ❑ Lake ❑ Erosion Hazard ❑ Wetlands ❑ Landslide Hazard ❑ Closed Depression ❑ CDal Mine Hazard ❑ Floodplain ❑ Seismic Hazard ❑ Other ❑ Habitat Protection Ll IIIIFTiN DINK43I11W Soil Type Arents, Wderwood Material Slopes 0 tD 15% ❑ High Groundwater Table (with in 5 feet) ❑ Other ❑ Additional Sheets Attached ❑ Sale Source Aquifer ❑ SeepsfSprings Erosion Potential :l Park 11 DRAINAGE DESIGN LIMITATIONS REFERENCE LIMITATION f BITE CONSTRAINT 21 Core 2 — Offsite Analysis ❑ BensitivelCrii ical Areas ❑ BEPA ] LID Infeasibility Other Geotech 1 :1 Additional Sheets Attached Park 12 TYR SUMMARY SHEET (provide one TIR Summary Shut 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 Anal, sis Level: 02 1 3 dated: 12}10rA18 Flaw Control (include facility Level: 1 f 2 1 3 or Exemption Number summary sheet) Flow Controf BMPs Infiltration Trench Conveyance System Spill containment located at: Erosion and Sediment Control l C-SWPPICIESCUESC Site Supervisor: Construction Btormwater Contact Phone: Pollution Prevention After Hours Phone: Maintenance and Operation Responsibility (circle one): oEite I Public If ::rivate, Maintenance Log Required: Yes o Financial Guarantees and Provided: Yes No Liability Water Quality (include facility Type (circle one)_ Basic Bens_ Lake I Enhanced Basic f Bog summary sheet) or Exemption No. Landscape Managrement Plan: Yes f No Special Requirements (as applicable): Area Specific Drainage Type: CDA f BDO f MDP f BP f LMP f Shared Fac. cone Requirements Name: FkxdplairJFloodway Delineation Type (circle one): Major f Minor I Exemption f None 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: 5 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Source Control Describe land use: (commercial I industrial land use) Describe any structural controls: Oil Control High -use Site: Yes No Treatment BMP: Maintenance Agreement: Yes f 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 ❑ Dewatehng Control ❑ Dust Control ❑ Flow Control Protection of BY4 Control BMP Facilities (existing and proposed) Maintain BMPs,` Manage Project 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, restore operation of Flow Control BMP Facilities as necessary ❑ Flag limits of SAO and open space preservation areas ❑ Other Part 14 STORMVVATER FACILITY DES CRIPT10NS (Note: Include Faci lity Summary and Sketch) FlavControl TypelDescription Water Quality TypefDescription ❑ Detention Infiltration ❑ Regional Facility ❑ Shared Facility ❑ Flow Control BMPs ❑ Other ❑ Vegetated Flovrpath ❑ wetpooi ❑ Filtration ❑ Oil Control ❑ Spill Control ❑ Flgw Control BMPs ❑ Other Infiltration Trench 0 Part 15 EASEMENTSITRACTS Part 16 STRUCTURAL ANALYSIS ❑ Drainage Easement j Cast in Place Vault ❑ Covenant J Retaining Wall ❑ Native Growth Protection Covenant ❑ Rockery > 4' High J Tract ❑ Structural on Steep Slope U Other J Other Part 17 SiCNATJRE'-]F PROFESSIONAL ENGINEER I; or a civil engineer under my supervision, have visited the site- Actual site oanditions as observed were incorporated into this worksheet and the attached Technical Information Report- To the best of my knorwledge the information provided here is accurate- 12J1M 18 sue, te 7 Figure 2 - Site Location SE 17$ND T k ME SE 173RD ST w d SE 774N ST � 1 SE PETRQVITSI4Y RQ n x Er Figure 3 - Drainage Basin/Downstream Path A Figure 4 - Soils ram+ � ■ - _..•-.� #�--�.r-=�� .� .�„_ _ � - � :- iRvw..�-� .+a�.a��_ �i�a f,ry < r�If King County Area, Washington (WA633) King County Area, Washington (WA533) 4 Map Unit Map Unit Name Acres percent in of AOI Symbol AOI AgB Alderwood gravelly 0.5 1.2% sandy loam, 0 to 8 percent slopes AgC Alderwood gravelly 26.1 59.80/0 sandy loam, 8 to 15 percent slopes AmC Arents, Alderwood 17.0 39.0% material, b to 15 percent slopes Totals for Area of 43.6 100.00/c Interest The project site is located in Arents, Alderwood material (AmC) and is surrounded, upstream and downstream by a similar soil, Alderwood gravelly sandy loam (AgB, AgC) of varying slopes. 10 2. CONDITIONS AND REQUIREMENTS SUMMARY CORE REQUIREMENT # 1: Discharge at the Natural Location Onsite stormwater, in the existing condition, sheet flows into SE 173rd St and into the City stormwater system. Stormwater, post site development, will continue to drain into the City stormwater system via infiltration trenches and associated stormwater conveyance system. CORE REQUIREMENT #2: Offsite Analysis See the Level 1 Downstream Analysis included in Section 3 of this TIR. CORE REQUIREMENT #3: Flow Control Infiltration trenches are proposed for each single family residence and the shared driveway. See Section 4. CORE REQUIREMENT #4: Conveyance System Conveyance capacity will be provided to handle peak flows from the 100-year storm event. See Section 5. CORE REQUIREMENT #5: Erosion and Sediment Control A construction entrance, silt fencing or compost socks, temporary drainage swales, and inlet protection along with appropriate cover measures will be provided for erosion and sediment control for the site. See Section 8. CORE REQUIREMENT #6: Maintenance and Operations A Maintenance and Operations Manual is provided in Appendix B of this report. CORE REQUIREMENT #7: Financial Guarantees and Liability Bond and liability assurances will be provided by the Owner or the Contractor. CORE REQUIREMENT #8: Water Quality The site is located within a Basic Water Quality Area. The project proposes 3,604 sf (individual driveways, shared driveway, and frontage) of Pollution Generating Impervious Surface (PGIS), which does not trigger water quality requirements, See Section 4. CORE REQUIREMENT #9: On -Site BMPs The project falls under Small Lot BMP requirements. Due to site constraints, an infiltration trench has been selected as a stormwater BMP (see Section 4) SPECIAL REQUIREMENT # 1: Other Adopted Area -Specific Requirements Not applicable. SPECIAL REQUIREMENT #2: Flood Hazard Area Delineation Not Applicable. SPECIAL REQUIREMENT #3: Flood Protection Facilities Not applicable. SPECIAL REQUIREMENT #4: Source Controls Not applicable. SPECIAL REQUIREMENT #5: Oil Control Not applicable. SPECIAL REQUIREMENT #6: Aquifer Protection Area The project is not located within an Aquifer Protection Area. 11 3. OFFSITE ANALYSIS (Level 1 Downstream Analysis) Task 1: Study Area Definition and Maps The study area covered was the project site and upstream and downstream drainage areas near the development property. Task 2: Resource Review The project site is located within the Black River Drainage Basin. Additionally, the site is not located in a critical drainage area. Research of available data shows no seismic hazard, landslide hazards, erosion hazards, or wetlands located on site. The soils on the site have been classified as Vashon Aged Glacial Till, see Geotech report. Task 3: Field Inspection Please refer to Figure 5 - Aerial Photograph and Figure 6 - Existing Site Conditions below to aid in the following description. Figure 5 - Aerial Photograph LPIP Mob- JF +t / 1 -�-- �- 1 . y.• ' i a _ 13814 S66theast • ;.- �•,r _173rd Street 4� R' 1 4 14 Catch Basin on NE corner of 108th Ave SE and SE 173rd St, collecting drainage from ditch. There are no signs of ponding, flooding, or erosion problems on site or downstream of the site. Tributary Upstream Drainage The project site is downstream of a condominium complex which has a separate conveyance system. As a result it is not considered to have an upstream basin. Task 4: Downstream Drainage System Description and Existing and Potential Problems Based on research, and site visits there are no signs of drainage or erosion problems. The site will be mitigated through infiltration trenches and will not contribute significant additional drainage to the city stormwater system. Drainage leaving the project site does so through sheet flow into a vegetated ditch on the north side of SE 173rd St. It then enters a series of 12" to 18" pipes which carries it south along 108th Ave SE. It then enters a vegetated swale and crosses Benson Dr. through an 18" CMP. It then travels west through a series of 12" to 18" pipes along SE 174th St. It reaches the 0.25 mile mark just shy of the SE 174th St and 106th PI SE Intersection. Conclusion: The downstream system showed no signs of erosion. No adverse impact to the downstream drainage system is expected from the proposed project. 15 4. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Existing Site Hydrology (Part A) The 10,800 sf project site is currently vacant. The site is covered with dense underbrush, deciduous trees, and evergreen trees along its frontage and property lines. The central portion of the property has been cleared. The site topography ranges from 0 to 15% across the property towards the southern portion of the site. There is currently no sidewalk on the frontage of the site. There is a vegetated ditch on the project frontage which collects and conveys stormwater to the west. The soil is classified as a Ardents, Alderwood Material by NRCS. The Geotech reports a typical soil log as 6" of top soil, then 2.5' of tan sand with some gravel, followed by 3' of compacted gray sand with some gravel. The soil log shows no evidence of mottling or water seepage. The site is bordered on the north, east, and west by single family homes as is typical of an urban residential neighborhood. 16 Developed Site Hydrology (Part B) Two new single family homes are proposed on each lot along with a proposed driveways and a shared access driveway. The project is subject to Directed Drainage Review (2 proposed single family residences, driveways, and shared driveway for a total of 6,843 sf of on -site impervious, along with 1,665 sf of frontage impervious, for a total of 8,508 sf of impervious for the project) which require that all 9 Core Requirements to be addressed as well as all 6 Special Requirements. Developed Area Exhibit: ........... ap � E; S Impervious Area Exhibit: t • 5 S SS SS 71 ---------------- 17 KEEP 5 FEET MIN. Dt%TANr.E FROM kwk7mi h3r4 TRENCH WALL TO ACAOFn 16 ROFrERlY &IM & 15 FROM 8LlILCI.r.CRAM�-AAAkCt *4 wm�voff cn?i xk r r r r Pix fir swliq VAN It= 3%=W�E— t W! — O'P- — 'A-- - Pr e Road _4 Mdeni ng: IMP-vAvrMmT 898 sf IN Total Developed Area Description SF Ac Total Property 10,800 0.25 Onsite Developed Area (cleared site, 839/6) 8,978 0.21 Pervious 2,135 0.05 Onsite Impervious 6,843 0.16 Proposed House 1 (Lot 1) 2,200 0.05 Proposed House 2 (Lot 2) 2,200 0.05 Proposed Driveways (Lot 1 & 2) 1,000 0.02 Proposed Shared Driveway 1,443 0.03 Frontage Developed Area 2,435 0.06 Frontage Impervious 1,665 0.04 Frontage Sidewalk 504 0.01 Frontage Driveway 263 0.01 Frontage Road Widening (PGIS) 898 0.02 Total Proposed Impervious 8,508 0.20 Total Developed Area (onsite & frontage area) 11,413 0.26 Performance Standards (Part C) The project site/each lot is <22,000 sf and therefore is required to apply the Renton Flow Control Standard OR Small Lot Flow Control BMPs. Due to the site's constraints and low infiltration rate (1 in/hr. from Geotech), we have chosen to abide by the Small Lot Flow Control BMPs requirements. Due to the site's classified sandy loam soils, we have chosen limited infiltration trenches as an On -site BMP per Core Requirement #9: On -Site BMPs for this project which will be explained in Part D. 19 Flow Control System (Part D) From the Small Lot BMP Requirement Feasibility Review: 1. Full Dispersion -Not Feasible. The site area is limited due to the proximity to property lines and does not have sufficient flow path lengths. 2. Full Infiltration - Not Feasible - Based on the soil type (sandy loam), this does not meet the requirements for Full Infiltration 3. Limited Infiltration - FEASIBLE Per the classified soil on site as sandy loam and the recommendations of the Geotech, we have chosen infiltration as a stormwater BMP. Sizing of trenches Per the recommendations of the Geotech and per the manual for sandy loam, For each 1,000 square feet of tributary impervious surface, will be mitigated by a 361 x 2'W x 2'D infiltration trench. This equates to 1000 sf of impervious being mitigated by 144 cf of gravel volume. Per the plans, each lot is mitigated by a 321 x 5'W x 2'D infiltration trench. The shared driveway is mitigated by a 35'L x 3'W x 2'D infiltration trench. Peak Flow Analysis The NRCS classifies the soil of the site as Arents, Alderwood Material, which is in SCS Hydrologic Soil Group "C". The total developed area of 0.26 ac is modeled as forest in the predeveloped condition. In the developed condition, all on -site impervious (0.16 ac) flows to the limited infiltration trenches (modeled as 90% impervious, 10% grass), frontage impervious is modeled as 100% impervious, and the new pervious areas on site are modeled as grass. This information is reflected in the following table: Land Cover Type (ac) Project Area Forest Pasture Lawn Impervious Total Impervious to Limited Infiltration (90% Impervious, 10% Grass) 0 0.02 0.14 0.16 Frontage Impervious 0.04 0.04 New Pervious Area 1 0.06 0.06 Total 01 01 0.081 0.18 0.26 20 W wi-im 2u 12, ana 15 minute times if KingM12 King2O12 Map Controls ■ �A� AiION-1 IVI�liiil Site Information Site Name Address City Gage Seatac Precip Factor �. ❑ Use S-DOT data 21 E�I,• Basin 1 Predeveloped Subbasin NamedBasin 1 Surface Interflow Groundwater Flows To Area in Basin F- Show Only Selected Available Pervious Acres r A/B, Forest, Flak A/B, Forest, Mod A/B, Forest, Steep A/B, Pasture, Flak A/B, Pasture, Mod A/B, Pasture, Steep A/B, Lawn, Flak A/B, Lawn, Mod A/B, Lawn, Steep C, Forest, Flak C, Forest, Mod C, Forest, Steep C, Pasture, Flak C, Pasture, Mod C, Pasture, Steep C, Lawn, Flak C, Lawn, Mod C, Lawn, Steep SAT, Forest, Flak SAT, Forest, Mod SAT, Forest, Steep Pervious Total Impervious Total Basin Total Precipitation Gage 0.26 Acres ® Acres 0.26 Acres DeseleckZero 11 Available Impervious Fv- ROADS/FLAT F- ROADSIMOD ROADS/STEEP ROOF TOPSIFLAT DRIVEWAYS/FL4T DRIVEWAYS/MOD DRIVEWAYS/STEEP SIDEWALKS/FLAT F- SIDEWALKSIMOD SIDEWALKSISTEEP PARKINGIFLAT PARKING/MOD PARKINGISTEEP POND Porous Pavement Acres 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 - <UNK> I seatac 15 minute Auto Assign Gages Select By: I GO 22 E�!,• Basin 1 Mitigated Subbasin Name: Basin 1 F- Designate as Bypass for POC: Surface Interflow Groundwater Flows To Area in Basin F- Show Only Selected Available Pervious Acres r A/B, Forest, Flak A/B, Forest, Mod A/B, Forest, Steep A/B, Pasture, Flak A/B, Pasture, Mod A/B, Pasture, Steep A/B, Lawn, Flak A/B, Lawn, Mod A/B, Lawn, Steep C, Forest, Flak C, Forest, Mod C, Forest, Steep C, Pasture, Flak C, Pasture, Mod C, Pasture, Steep C, Lawn, Flak 0 C, Lawn, Mod C, Lawn, Steep SAT, Forest, Flak SAT, Forest, Mod SAT, Forest, Steep Pervious Total Impervious Total Basin Total Precipitation Gage 0.08 Acres 0.18 Acres 0.26 Acres Deselect Zero 11 Available Impervious Fv- ROADSIFLAT F- ROADSIMOD ROADSISTEEP ROOF TOPSIFLAT DRIVEWAYS/FL4T DRIVEWAYS/ DRIVEWAYS/STEEP SIDEWALKS/FLAT F- SIDEWALKSIMOD F- SIDEWALKSISTEEP PARKINGIFLAT PARKINGIMOD PARKINGISTEEP POND Porous Pavement Acres .18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 - <UNK> I seatac 15 minute Auto Assign Gages Select By: I GO 23 Flow Frequency Flow{cfs} Predeveloped Mitigated 2 Year = 0.0076 0.0738 5 Year = 0.0120 0.0951 10 Year = 0.0145 0.1099 25 Year = 0.0171 0.1293 50 Year = 0.0187 0.1444 100 Year = 0.0201 0.1599 0.1599 - 0.0201 = 0.1398 cfs (Full WWHM Report found in Appendix G) Difference in peak flow is 0.1398 cfs which is below the 0.15 cfs threshold required for flow control. Since we have modeled the frontage impervious as part of this model, which is exempt from flow control, we are exempt from Core Requirement #3. Core Requirement #9: Onsite BMPs does not apply to frontage improvements. The word "site" in "Onsite" is defined as the following: "a single parcel; or, two or more contiguous parcels that are under common ownership or documented legal control; or a portion of a single parcel under documented legal control separate from the remaining parcel, used as a single parcel for a proposed project for purposes of applying for authority from the City to carry out a proposed project. For projects located primarily within dedicated rights -of - way, the length of the project site and the right-of-way boundaries define the site." Water Quality System (Part E) The project proposes 3,604 sf (lot driveways (1000 sf), shared driveway (1,443 sf), frontage driveway (263 sf), and road widening (898 sf)) of Pollution Generating Impervious Surface (PGIS), which is under the 5,000 sf threshold requirement for water quality. Therefore, Water Quality is NOT required. 24 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN Conveyance system will be designed in accordance with the 2017 RSWDM. For a factor of safety, the basin is modeled as the fully developed area that was conducted in the "Peak Flow Analysis" including roofs, lot driveways, shared driveway, pervious area, and all frontage impervious which will be conveyed to the most constrained pipe on the project, a 6" pipe at 2% slope. Using Manning's equation to determine pipe capacity for a 6" diameter pipe (minimum designed) at 2.0% minimum slope and a typical Manning's coefficient of 0.013 for PVC pipe: Channel Calcs Depth Q (fl) {cs� 050 07913 Section Type= 6tm Width (ft) Side Slope,z1 = Di ameter(ft) = Inv Elew(ft)= Slope (%)= n-value = Compute by= Increments = Area wi.. Wp (sgfl) Vtri� M 9.196 4D4 1b- Circular 0.50 10D.0D 2.0D 0.013 Q vs Depth 1 Y. 045 Pipe Capacity = 0.793 cfs > Ql oo = 0.1599 cfs 4 OK TopWidth M 000 25 6. SPECIAL REPORTS AND STUDIES -Geotechnical Report by The Concept Group. (See Appendix D) 7. OTHER PERMITS -None 8. CSWPPP ANALYSIS AND DESIGN Less than an acre of disturbance is anticipated for this project. Proposed temporary measures possible for this project will include the following BMP's: • Construction Entrance • Filter fences or Compost Socks. • Straw mulch, hydroseed or other mulching and planting method to stabilized unworked areas. • Temporary drainage swales and rock check dams. • Inlet protection of new and existing catch basins. Please refer to the TESC Plan included in the Engineering Submittal for details, along with a further CSWPPP explanation in Appendix C. 9. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION OF COVENANT Bond and liability assurances will be provided by the Owner or the Contractor. A Declaration of Covenant for the Flow Control BMPs will be recorded with Renton prior to final approval. Copies of these are included in Appendix E and F, respectively. 10.OPERATIONS AND MAINTENANCE MANUAL An Operations and Maintenance Manual is included in Appendix B of this report. 26 Appendix A Stormwater Site Plans 89E000Oz:O L80000-6L:vni 9LL000-6L:?!d 1Vld iNOHS NVHOOON o � 8 o ` d o= z O u 'j rc= Q O w Q Z Q w Hp ¢ O ))3 F� �O D ¢ �z. oZz Z CO U U co 3� �o2 W w o 0 rcr -oi U rcm Z qJ o0 M o w� 0 C7 �rc mwwz arcz Xa 1 mo J w J rc� Q F fA �rc w oF'o y O F O Oz� U ¢ a N ry o x wy Zm2 �w LL N ww Z Q w « N oow ona x zaaw $z� W- �z��� Q IaL o ? a Qi Ct .��^ a0�=e �w= ¢a ¢ W �<w zw w =�< Q �=��a g a o5 Z= U Z22wi �QOroO Q J ¢ Q J mow yCII�FF� 3w QW �`� m ow�w oxrc$rc Q 0 5J �°Uli a.,R,n OOi �rc PIE f [ �2 3 � { �f �6 ✓`�a 2 ■ lilQ�AE S — � � a � z � � � i Y�I U7 b a S P e iF fg jib i pip g aiE oil 1. 1 oj�if o sItI i Q wti € lily Ff9 3 `5C lls I � Ij Rq{ j]{ E 3 (} � ¢ Q . gS 15•� 10 ■eEi l i fil f e ag ] tl iif g a e @ 7 4$$ y€E a 888 p$ E {ypppppp yp:y$( gg3 �s pppY $ i ygS €a5 p{C Y Y T I Hill ll gE $�£ppl SSgygy p gg Y pp �' E 13�$i a(�'� r S pL y $ 33ii[ i $ pk1 8iii� lg @ IH �i4 R Y�7Fi � i I �if �� INN E66Fj� 1 IC■F:� It J J R fR U 5? a� FU� ly a �om �y Uw J 2 o O w� o 0 ofN �N g �°wm yN,n�a w eto. rn aa'�4° a H Z y FNr o l M w z r m a it z g�.� m, o`S O co�u L oO N o co �1 ll a �3N 8 L L7-07-431 1Vlld 1210HS NVHOOON L 133HS "°°°' " °"' ° °' b °nO-Sd-SZ£8 "\s6ui.m4\Q"v0\O°id V °°"=°e") "•ns wsu as sieo - szsew\6°., \a °wd °°" Wass z, - ozoz W­ co 0o r 3�0 zo W 3 a� o o a � N O w 0 ko �I - O wVld a U 3 „Ol,4D.10 N 30 - 5 \ Z O 509 x ____- l O C\2 yom" o 0 ,LO'OZI 3 „0 L,44.10 N ________ _ _ _______ __SM,9 -O 0 0 0 II I —'06-OF 30 rnl OJ rol :ooas I o - z w F z z r a 3�u�i - zoo r 3Q�e c sue. ooz` 686 o6x w To o�z co Vr o � - o =a� w a s m O rc3 ~ 2TTV-0-k—QRz E9£0000z:0 L90000-66:Vni 9L6000-66:1:1d 1Vld BdOHS NVHOOON 41 el u [My �g2� frd�Yb� g � 1i_DO pilll5a il e�� G�G�� 3 � ��� j wit 0 1�f I � � .11 !pill� ■�$ � F pig $} fir}fi 1 p s pm p� z�z a eIII � a pp jF � iill pp 88 pi a � $�a�p' �p iJa � pp pfif� a i� g a� �� ��_ �■� a � �yg[r �g[ �7� jEg� 4a a killSEE g �gg ��"� �� � €f g■` i r rg Mh 111 sa � p $j aYY as [{$ igyjg $glitq g Q PRO R H i� r d X ig R �Ye aS a# bg i i 3 gp$ 9 OgpPgp ig agjj g9�$j z $ i gele gg 2°al !€ Hill i€ $ $Ej� w$ E Y S i Z w 3 W o z w 0 w O Q J o rc cwi z o t z E o (A o w¢ w rc w a- 3 o w w o o z o rc Z h w Z z o o LL a w w 11 w w, "per Z w o N Nw w o U �3s zw o o �� z w LL w m Q j ¢ w, j w i Z a a F o w o G m t s 4 p ¢ P p^ i i¢< G r m .w i w Z tia No�wFw oywruw sjQ mot wrap w Rm O w orc°= ° and U Wzo oipmp ao�z �w< z. z.3i°ow w ozimuwzua zdoot �~iuioa~rco?co'�o rc ood W O z z cJi m r w o ? w 3 Q o§ 6 4 F i o< ' o w w w i Q of w o z 2 Fz�w z�zwtiF�mmo zpz�ao omwzQ�Np w< a;w�d W osLL¢oww o� iw " i< Jr` WWU O p w F a aFW y¢ pm m J �zw OO O> rcz om 0m i rr> Orc om¢ j wh w F w wu rc o w w w w. w ronzr «,o� _ ----o: z �z o 1r z w���ww N az. a-o -- _-- -� "ao O� J M m J� z w 1=e I I I I I I I I £667-0b-(131 woQ ^ z w, ,y� sw z�w �d �� - bU) o — 1 of rU 5 W (J) ~w� 0 a L o Z 0 C1 z a Q W o Z Q 0 LU U_ z� U U) H 00 U) o N E I N m LLN �z-� <w --- - �� 7wa a o v ,I w d mo a oFN 1Vld 1210HS NVHOO°JN £ 133HS n m :=wox m�o3 e.c 103-se-9zssL8Vc--O\OOVOV4md m --1) r=as wsu 3s nao - szcaw c ,om I -1d ozoz o0 om G 12 89s0000z:0 L80000-61:vni 9M00-% 21d 1Vld 1NOHS NVHOOON o w u Q $ N 3$ ww y a o y o n yz wwN i z0. tt o a�ay a =Qag o Fn Qo - w aWN- �o>2r m �"emp $ NwgaLE ¢Oof�Z w �WOwo"99j ' ¢mow �tw�- N a mtwr�� �zZm Z Z�awrcWW Z $ U�amrcW ® ® ® ® o O ¢ ry U K O ¢ K ¢ > o w oo W OW 2 3N 3N a o w ¢w oo r$ U p -,w w >F. 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Infiltration deTaces, such as gravel filled trenches, drywells. and ground surface depressions. facilitate this process by putting rtmotf in direct contact with the soil and holding the mnoff long enough to soak most of it into the ground_ To be successful, the soil condition around the infiltration device must be able to soak water into the grmmd for a reasonable number of years_ Infiltration Desires The infiltration deuces used on your property include the following as indicated on the flow control BMP site plan (CHECK THE BOXES) THAT APPLY): ❑ gravel filled trenches, ] drywells_ MAINTENANCE RESTRICTIONS The sue_ placement, and composition of these devices as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King Cotnmty. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES To be successful. the soil condition around the infiltration device must be able to soak water into the ground for a reasonable number of years. • Infiltration devices antst be inspected auttally and after major storm events to identify and repair any physical defects_ • Maintenance and operation of the system should focus on ensuring the system's viability by preventing sediment -laden flows from entering the device. Excessive sedimentation will result in a plugged or non-functioning facility. • If the infiltration device has a catch bash. sediment accumulation must be removed on a yearly basis or more frequently if necessary_ • Prolonged ponding arotmd or atop a device may indicate a plugged facility. If the device becomes plugged it must be replaced_ • Keeping the areas that drain to infiltration devices well swept and clean will enhance the longevity of these devices. • For roofs, frequent cleaning of gutters will reduce sediment loads to these det ices_ RECORDING REQUIREMENT These limited infiltration flow control BMP maintenance and operation instnxtions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C_13_4 of the King Cotm ty Surface Water Design Manual_ The intent of these instructions is to explain to fitture property owners, the purpose of the BMF and how it nntst be maintained and operated. These instructions are intended to be a mimnnun; the King County Department of Permitting and Environmental Services (DPER) may require additional instructions based on site - specific conditions. See King County's Surface Water Design Manual %%rbsite for additional information and updates. 29 Appendix C CSPPP 30 CESCL REQUIREMENT A Certified Erosion and Sediment Control Specialist shall be identified in the Construction SWPPP and shall be onsite or oncall at all times. Certification may be obtained by an approved training program that meets the erosion and sediment control training criteria established by Ecology. If a preconstruction meeting is held, this person shall attend. See attached BMPC160 Certified Erosion and Sediment Control Lead (CESCL) CESCL 24hr Contact number: Fax number: Address: ELEMENT 1 : MARK CLEARING LIMITS • Prior to beginning land disturbing activities, including clearing and grading, all clearing limits, sensitive areas and their buffers, and trees that are to be preserved within the construction area should be clearly marked, both in the field and on the plans, to prevent damage and offsite impacts. • Plastic, metal, or stake wire fence may be used to mark the clearing limits. • The duff layer, native topsoil, and natural vegetation shall be retained in an undisturbed state to the maximum extent practicable. If it is not practicable to retain the duff layer in place, it should be stockpiled onsite, covered to prevent erosion, and replaced immediately upon completion of the ground disturbing activities. Element #1 BMP Description X C101 Preserving Natural Vegetation X C102 Buffer Zones X C103 High Visibility Plastic or Metal Fence X C104 Stake and Wire Fence Construction and silt fencing will be used to delineate the limits of clearing for the project. ELEMENT 2: ESTABLISH CONSTRUCTION ACCESS • Construction vehicle access and exit shall be limited to one route if possible. • Access points shall be stabilized with quarry spalls or crushed rock to minimize the tracking of sediment onto public roads. • Wheel wash or tire baths should be located onsite, if applicable. • Public roads shall be cleaned thoroughly as needed to protect stormwater infrastructure and downstream water resources. Sediment shall be removed from roads by shoveling or pickup sweeping and shall be transported to a controlled sediment disposal area. Street washing will be 31 allowed only after sediment is removed in this manner. • Street wash wastewater shall be controlled by pumping back onsite, or otherwise be prevented from discharging untreated into systems tributary to state surface waters. Element #2 BMP Description X C105 Stabilized Construction Entrance C106 Wheel Wash C107 Construction Road/Parking Area Stabilization The proposed construction accesses will be from SE 1731 St on the south property line. ELEMENT 3: CONTROL FLOW RATES • Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site, as required by local plan approval authority. • Downstream analysis is necessary if changes in flows could impair or alter conveyance systems, stream banks, bed sediment or aquatic habitat. See Chapter 3 for offsite analysis guidance. • Where necessary to comply with Minimum Requirement #7, stormwater retention/detention facilities shall be constructed as one of the first steps in grading. Detention facilities shall be functional prior to construction of site improvements (e.g. impervious surfaces). • The local permitting agency may require pond designs that provide additional or different stormwater flow control if necessary to address local conditions or to protect properties and • waterways downstream from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. • If permanent infiltration ponds are used for flow control during construction, these facilities shall be protected from siltation during the construction phase and plans made for restoration after construction. Element BMP Description #3 C240 Sediment Trap C241 Temporary Sediment Pond ELEMENT 4: INSTALL SEDIMENT CONTROLS Prior to leaving a construction site, or prior to discharge to an infiltration facility, stormwater runoff from disturbed areas shall pass through a sediment pond or other appropriate sediment removal BMP. Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but must meet the flow control performance standard of Element #3, bullet #1. Full stabilization means concrete or asphalt paving; quarry spalls used as ditch lining; or the use of rolled erosion products, a bonded fiber matrix product, or vegetative cover in a manner that will fully prevent soil erosion. The local permitting authority should inspect and approve areas stabilized by means other than pavement or quarry spalls. • Sediment ponds, vegetated buffer strips, sediment barriers or filters, dikes, and other BMP's intended to trap sediment onsite shall be constructed as one of the first steps in grading. These 32 BMP's shall be functional before other land disturbing activities take place. • Earthen structures such as dams, dikes, and diversions shall be seeded and mulched according to the timing indicated in Element #5. • BMPs intended to trap sediment on site must be located in a manner to avoid interference with the movement of juvenile salmonids attempting to enter off -channel areas or drainages, often during nonstorm events, in response to rain event changes in stream elevation or wetted area. Element #4 BMP Description C230 Straw Bale Barrier C231 Brush Barrier C232 Gravel Filter Berm X C233 Silt Fence C234 Vegetated Strip C235 Straw Wattles C240 Sediment Trap C241 Temporary Sediment Pond C250 Construction Stormwater Chemical Treatment C251 Construction Stormwater Filtration The proposed sediment control measures are provided on TESC found in the engineering submittal. At minimum, the project will be required to have downstream protection (compost socks, silt fencing, or equivalent), inlet protection, and appropriate cover measures. The proposed plan is intended as guidance and the Contractor shall be responsible for implementing and maintaining appropriate sediment controls based on changing site conditions. ELEMENT 5: STABILIZE SOILS • All exposed and unworked soils shall be stabilized by application of effective BMPs that protect the soil from the erosive forces of raindrop impact, flowing water, and wind. • Soils shall be stabilized as outlined below, where downstream water resources or stormwater infrastructure may be negatively affected by sediments (i.e., runoff discharges off the development site). • From October 1 through April 30, no soils shall remain exposed and unworked for more than 2 days. From May 1 to September 30, no soils shall remain exposed and unworked for more than 7 days. This condition applies to all onsite soils, whether at final grade or not. The local permitting authority may adjust these time limits if it can be shown that a development site's erosion or runoff potential justifies a different standard. • Applicable practices include, but are not limited to, compost addition, temporary and permanent seeding, sodding, mulching, plastic covering, soil application of polyacrylamide (PAM), early application of gravel base on areas to be paved, and dust control. • Soil stabilization measures selected should be appropriate for the time of year, site conditions, estimated duration of use, and potential water quality impacts that stabilization agents may have on downstream waters or ground water. 33 • Soil stockpiles must be stabilized from erosion, protected with sediment -trapping measures, and located away from storm drains, waterways, or drainage channels. • Work on linear construction sites and activities, including right-of-way and easement clearing, roadway development, pipelines, and trenching for utilities, shall not exceed the capability of the individual contractor for his portion of the project to install the bedding materials, roadbeds, structures, pipelines, and/or utilities, and to re -stabilize the disturbed soils, in compliance with the applicable 2-day or 7-day criterion listed above. Element #5 BMP Description X C120 Temporary and Permanent Seeding X C121 Mulching C122 Nets and Blankets X C123 Plastic Covering X C124 Sodding X C125 To soilin C126 Polyacrylamide for Soil Erosion Protection C130 Surface Roughening C131 Gradient Terraces C140 Dust Control C180 Small Project Construction Stormwater Pollution Prevention Temporary and permanent cover measures shall be provided based upon plans and Contractor's discretion per site conditions during construction. ELEMENT 6: PROTECT SLOPES • Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. • Consider soil type and its potential for erosion. • Reduce slope runoff velocities by reducing the continuous length of slope with terracing and diversions, reduce slope steepness, and roughen slope surface. • Offsite stormwater (run-on) shall be diverted away from slopes and disturbed areas with interceptor dikes and swales. Offsite stormwater should be managed separately from stormwater generated on the site. • To prevent erosion, at the top of slopes collect drainage in pipe slope drains or protected channels. Temporary pipe slope drains shall handle the peak flow from a 10-year, 24-hour event; permanent slope drains shall be sized for a 25-year, 24-hour event. Check dams shall be used within channels that are cut down a slope. • Provide drainage to remove ground water intersecting the slope surface of exposed soil areas. • Stabilize soils on slopes, as specified in Element #5. Element #6 BMP Description X C120 Temporary and Permanent Seeding X C130 Surface Roughening X C131 Gradient Terraces C200 Interceptor Dike and Swale 34 C201 Grass -Lined Channels C204 Pipe Slope Drains C205 Subsurface Drains C206 Level Spreader C207 Check Dams C208 Triangular Silt Dike The Contractor shall be responsible for protecting and stabilizing site slopes as required. ELEMENT 7: PROTECT DRAIN INLETS • As needed to protect stormwater infrastructure and downstream water resources, all storm drain inlets made operable during construction shall be protected so that stormwater runoff shall not enter the conveyance system without first being filtered or treated to remove sediment. • All approach roads shall be kept clean, and all sediment and street wash water shall not be allowed to enter storm drains without prior and adequate treatment, unless treatment is provided before the storm drain discharges to waters of the State. Element BMP Description #7 X C220 Storm Drain Inlet Protection Both existing and proposed drain inlets shall be protected as required. ELEMENT 8: STABILIZE CHANNELS AND OUTLETS • All temporary onsite conveyance channels shall be designed, constructed and stabilized to prevent erosion from the peak 10-minute flow velocity from a Type 1A 10-year 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate indicated by an approved continuous runoff model, increased by a factor of 1.6, may 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 BMP Description #8 C202 Channel Lining X C209 Outlet Protection Permanent conveyance channels shall be, at a minimum, lined with grass. Outlets to open drainage areas shall be lined with rip -rap. 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. • Cover, containment, and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and non -inert wastes present on the site (see Chapter 173-304 WAC for the definition of inert waste). Onsite fueling tanks shall include secondary containment. • Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain down, solvent and de -greasing cleaning operations, fuel tank drain down and removal, and 35 other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Report all spills to 911. Emergency repairs may be performed onsite using temporary plastic placed beneath and, if raining, over the vehicle. • Wheel wash, or tire bath wastewater, shall be discharged to a separate onsite treatment system or to the sanitary sewer if allowed by the local wastewater authority. • Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' label recommendations shall be followed for application rates and procedures. • Management of pH -modifying sources shall prevent contamination of runoff and stormwater collected on the site. These sources include, but are not limited to, bulk cement, cement kiln dust, fly ash, new concrete washing and curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, and concrete pumping and mixer washout waters. • Construction sites with significant concrete work shall adjust the pH of stormwater if necessary to prevent violations of water quality standards. 36 Element BMP Description #9 X C151 Concrete Handling X C152 Sawcutting and Surfacing Pollution Prevention The Contractor shall be responsible for controlling pollutants from construction activities off the project site. ELEMENT 1 0: CONTROL DE -WATERING • All foundation, vault, and trench de -watering water, which has similar characteristics to stormwater runoff at the site, shall be discharged into a controlled conveyance system, prior to discharge to a sediment trap or sediment pond. Channels must be stabilized, as specified in Element #8. • Clean, non -turbid de -watering water, such as well -point ground water, can be discharged to systems tributary to state surface waters, as specified in Element #8, provided the de -watering flow does not cause erosion or flooding of the receiving waters. These clean waters should not be routed through sediment ponds with stormwater. • Highly turbid or otherwise contaminated dewatering water, such as from construction equipment operation, clamshell digging, concrete tremie pour, or work inside a cofferdam, shall be handled separately from stormwater at the site. • Other disposal options, depending on site constraints, may include: 1) infiltration, 2) transport offsite in vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters, 3) onsite treatment using chemical treatment or other suitable treatment technologies, or 4) sanitary sewer discharge with local sewer district approval. The Contractor shall be responsible for discharging de -watering water in an appropriate manner. ELEMENT 1 1 : MAINTAIN BMP's • All temporary and permanent erosion and sediment control BMP's shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with BMP's. • Sediment control BMP's shall be inspected weekly or after a runoff -producing storm event during the dry season and daily during the wet season. • All temporary erosion and sediment control BMP's shall be removed within 30 days after final site stabilization is achieved or after the temporary BMP's are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal of BMP's or vegetation shall be permanently stabilized. The Contractor shall be responsible for maintaining BMP's to assure performance of their intended function. ELEMENT 1 2: MANAGE THE PROJECT • Phasing of Construction - Development projects shall be phased where feasible in order to prevent soil erosion and, to the maximum extent practicable, the transport of sediment from the project site during construction. Revegetation of exposed areas and maintenance of that vegetation shall be an integral part of the clearing activities for any phase. 37 Clearing and grading activities for developments shall be permitted only if conducted pursuant to an approved site development plan (e.g., subdivision approval) that establishes permitted areas of clearing, grading, cutting, and filling. When establishing these permitted clearing and grading areas, consideration should be given to minimizing removal of existing trees and minimizing disturbance/compaction of native soils except as needed for building purposes. These permitted clearing and grading areas and any other areas required to preserve critical or sensitive areas, buffers, native growth protection easements, or tree retention areas as may be required by local jurisdictions, shall be delineated on the site plans and the development site. All plats shall include lot -specific grading plans, including information specified by the local permitting authority such as finished grades, finished floor elevations, buildable areas, and identified drainage outlets. This information would normally be submitted with the construction drawings, but may be required prior to preliminary plat approval. • 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 construction site through a combination of the following: 1. Site conditions including existing vegetative coverage, slope, soil type and proximity to receiving waters; and 2. Limitations on activities and the extent of disturbed areas; and 3. 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. If, during the course of any construction activity or soil disturbance during the seasonal limitation period, silt -laden runoff leaving the construction site causes a violation of the surface water quality standard or if clearing and grading limits or erosion and sediment control measures shown in the approved plan are not maintained, the local permitting authority may take enforcement action, including but not limited to a notice of violation, administrative order, fine/penalty, stop - work order, or correction notice. The following activities are exempt from the seasonal clearing and grading limitations: 1. Routine maintenance and necessary repair of erosion and sediment control BMP's; 2. Routine maintenance of public facilities or existing utility structures that do not (a) expose the soil or (b) result in the removal of the soil's vegetative cover; and Self-contained project sites, where there is complete infiltration of the water quality design event runoff within the site. 3. Local governments may restrict clearing and grading activities where site conditions may present a significant risk of impact to property or critical areas. Contact the local permitting authority for information on specific site restrictions. In Olympia, except where approved chemical treatment, full dispersion or infiltration is practiced, clearing, grading, and other soil disturbing activities are prohibited in all watersheds November through February, and in Green Cove, Percival, Woodard, and Ellis Creek watersheds between October through April. • Coordination with Utilities and Other Contractors The primary project proponent shall evaluate, with input from utilities and other contractors, the stormwater management requirements for the entire project, including the utilities, when preparing the Construction SWPPP. • Inspection and Monitoring All BMP's 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. The person shall have the skills to (1) assess site conditions and construction activities that could impact stormwater runoff quality, and (2) assess erosion and sediment control measure effectiveness. A Certified Erosion and Sediment Control Specialist shall be identified in the construction SWPPP and shall be onsite or on -call at all times. Certification may be obtained an approved training program that meets the erosion and sediment control training criteria established by Ecology. If a pre -construction meeting is held, this person shall attend. Sampling and analysis of the stormwater discharges from a construction site may be necessary on a case - by -case basis to ensure compliance with standards. Monitoring and reporting requirements may be established by the local permitting authority when necessary. The following discharge standard applies: Runoff leaving the construction site shall be free of settle able solids, as measured with an Imhoff Cone and in accordance with Standard Methods for the Examination of Water and Wastewater, most recent edition, American Water Works Association. "Free of settle able solids" shall be defined as measuring less than 2.5 mL/L/hr, for storms up to the water quality design event.1 The following surface water standard applies: 1. For storms up to the water quality design event, turbidity downstream of a construction site may not increase more than 5 NTU, if upstream turbidity is 50 NTU or less, and may not increase more than 10 percent, if upstream turbidity is over 50 NTU. To the extent practicable, samples should be taken far enough downstream so that the construction site discharge has been well - mixed with the surface water. 2. Whenever inspection and/or monitoring reveals that the BMP's identified in the Construction SWPPP are inadequate, due to the actual discharge of or potential to discharge a significant amount of any pollutant, appropriate BMP's or design changes shall be implemented as soon as possible. Maintaining an Updated Construction SWPPP - The SWPPP shall be retained onsite or within reasonable access to the site. The SWPPP shall be updated within 7 days to reflect any significant changes in the design, construction, operation, or maintenance at the construction site that have, or could have, a significant effect on the discharge of pollutants to waters of the state. The SWPPP shall be updated within 7 days if during inspections or investigations by site staff or local or state officials, it is determined that the SWPPP is ineffective in controlling pollutants such that applicable discharge or surface water standards violations are apparent. The objective is to control erosion and prevent sediment and other pollutants from leaving the site during the construction phase of a project. The Contractor shall be responsible for managing the construction phase of the project within reasonable applications of the guidelines of this section and the SWPPP. 39 SECTION 3 - CONSTRUCTION SWPPP CHECKLIST Construction Stormwater Pollution Prevention Plan Checklist Project Name: City Reference No_ Re--iew Date: ou-site Inspection Revie�,N-- Date: Constnuction SW- PPP Reviewer: Section I — Construction SWPPP Narrative 1. Construction Stormwater Pollution Prevention Elements _ a. Describe hove each of the Construction Stormu-ater Pollution Prevention Elements has been addressed though the Construction SINTPP. b. Identify the type and location of BPs used to satisfy the required element. c. Written justification identifying the reason an element is not applicable to the proposal. 12 Required Elements - Construction Stormwater Pollution Prevention Plan 1 _ Mark Clearing Limits_ _ 2. Establish Construction Access. _ 3 _ Control Flow Rates_ _ 4. Install Sediment Controls_ _ S . Stabilize Sails. 6. Protect Slopes. _ 7. Protect Drain Inlets. 8. Stabilize Channels and Outlets. _ 9. Control Pollutants. 14_ Control De -Watering. _ 11. Maintain BMPs 12_ Manage the Project. 2. Project Description _ a. Total project area. b. Total proposed iuipervions area_ c. Total proposed area to be disturbed„ including off site borrow and fill areas. d. Total volumes of proposed cut and fill_ 3. Existing Site Conditions a. Description of the existing topography. b. Description of the existing ;vegetation. c. Description of the existing drainage. February 2005 Volume N — Construction Stormwater Poftutron Preventton 3-21 .E Construction Stormwater Pollution Prevention Plan Checklist Project Name. City Reference No_ 4. Adjacent Areas I_ Description of adjacent areas which may be affected by site disturbance a_ Streams b. Lakes c_ Wetlands d. Residential Areas e_ Roads f Other II. Description of the &-kynstream drainage path leading from the site to the receiving body ofwater. (Minimum distance of 400 y-ards_) 5. Critical Areas _ a. Description of critical areas that are on or adjacent to the site. b. Description of special requirements for working in or near critical areas. 6. soils Description of on -site sails_ a_ Soil name(s) b_ Soil mapping unit _ c_ Erodibilih, _ d_ Settleability e_ Penneability f. Depth g_ Texture h_ Soil Stricture i. Erasion Problem Areas Description of potential erosion problems on site. S. Construction Phasiug _ a. Construction sequence b_ Constniction plea;ing (if proposed) 3-22 Volume N — Construction Stormwater PdUron Preventrorr February 2005 41 Construction Stormwater Pollution Prevention Plan Checklist Project Name. City Reference No_ 9. Construction Schedule I. Provide a proposed construction schedule_ II_ Wet Season Construction Activities _ a_ Proposed wet season construction activities. b. Proposed vet season construction restraints for environmentally sensitive..critical areas. 10. Finaacial-"Ownership Responsibilities a. Identify the property owner responsible for the initiation of bands andior other financial securities_ b. Describe bonds and?or other evidence of financial responsibility- for liability associated with erasion and sedimentation impacts. 11. Engineeizng Calculations 1. Provide Design Calculations_ a_ Sediment Ponds."Traps _ b. Diversions _ c_ Waterways d. Runaff'Stormwater Detention Calculations February 2005 Volume N — Construction Stonnwa ter Pollution Prevention 3-23 42 Construction Stormwater Pollution Prevention Plan Checklist Project Name: City Reference No_ 1_ General a_ Vicinity Map b_ City of Section II - Erosion and Sediment Control Plans Clearing and Grading Approval Block Erasion and Sediment C:ontrolNotes 2. Site Plan _ a. Legal description of subject property. b. North Arro-,r c. Indicate boundaries of existing vegetation, e.g_ tree lines, pasttue areas, etc. d. Identify and label areas of potential erosion problems_ e. Identify any on -site or adjacent siuface vv'aters, critical areas and associated buffers. f_ Identify FEMA base flood boundaries and Shoreline Management boundaries (if applicable) g. Shove existing and proposed contours. h. Indicate drainage basins and direction of floor for individual drainage areas_ i_ Label final grade contours and identify developed condition drainage basins_ j_ Delineate areas that are to be cleared and graded. k. Show all cut and fill slopes indicating top and bottom of slope catch lines. 3. Conveyance Systems a_ Designate locations for swales, interceptor trenches, or ditches- b. Shaw all temporan• and permanent drainage pipes, ditches, or cut-off trenches required for erosion and sediment control_ c_ Provide minimum slope and cover for all temporary pipes or call out pipe inverts_ d_ Shove grades,_ dimensions, and direction of flow in all ditches, su, ales, culverts and pipes_ e_ Provide details for bypassing off -site runoff around disturbed areas_ f. Indicate locations and outlets of any dewatering systems_ 4. Location of Detention BMPs a. Identify location of detention BMPs_ 3-24 Volume N — Conshwct+on Stormwa ter Poltution Pmvenfiorr February 2005 43 Construction Storrnwater Pollution Prevention Plan Checklist ProjectName: City Reference No_ a. Erosion and Sediment Control Facilities a_ Show the locations of sediment traps), pond(s), pipes and strictures. b. Dimension pond berm widths and inside and outside pond slopes_ c. Indicate the trap pond storage required and the depth. length, and Width dimensions. d. Provide typical section views through pond and outlet stnicture. e. Provide typical details of gray.el cone and standpipe; and. -'or other filtering devices_ f_ Detail stabilization techniques for outlet."inlet_ g. Detail controL'restrictor dele-ice location and details_ _ h. Specify mulch andior recommended cover of berms and slopes. _ i_ Provide rock specifications and detail for rock check dam(s)_ if applicable_ j_ Spe€ify spacing for rock check dams as required. _ k. Provide front and side sections oftypi€al rock check dams_ L Indicate the locations and provide details and specifications for silt fabric. m_ Locate the construction entrance and provide a detail_ 6. Detailed Drawings a. Any structural practices used that are not referenced in the Ecology Manual should be explained and illustrated with detailed drawings_ 7. Other Pollutant BIIPs a_ Indicate on the site plan the location ofBMPS to be used for the control of pollutants other than sediment, e.g_ concrete wash water. S. Monitoring Locations a_ Indicate on the site plan the water quality sampling locations to be used for monitoring water quality on the construction site, if applicable. February 2005 1loluffie 11— Construction Stormwater Pollution Prevenfion 3-25 Appendix D Geotech/NRCS DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331 B Date: To: From: MEMORANDUM 4/Ul JVV Aamlral nay, Jte 3b3 • Jeattle, vm y)bl lb be 1 LUb.44b.Iale www.uonceptbusinessuroup.com March 13, 2020 City of Renton Anna Nguyen, P.E. ad Subject: Infiltration Assessment "4"''". A-trj ``"' Project Address: 10814 SE 173rd Street DOWMAM134M.- Geologic Setting The Geologic Map of King County, by Derek B. Booth, Kathy A. Troost & Aaron P. Wisher published in March 2007, was referenced for the geologic and soil conditions of the project site. According to this publication, the surficial soil unit at the project site and its immediate vicinity is mapped as Ti I I (Qvt). - projecIti location -9 ii f Figure 1 - Geologic Map of Des Moines (Not -to -Scale) Soils on this property were investigated under my supervision on March 8, 2020. Three (3) test pits were excavated in the vicinity of the proposed stormwater BMP locations. In accordance with Section C.2.2 of the 2016 King County Surface Water Design Manual, soil logs are required to be excavated to a minimum depth of 5 feet. Refer to Figure 2 for the test pit locations and Figure 3 for the soil log. A NEW DIMENSION OF DESIGN PERCEPTION DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331 B 10814 Southeast 173rd Street Page 2 of 3 Figure 2 - Soils Test Pit Location (Not -to -Scale) Groundwater The soil sample was collected during the wet -season. No groundwater seepage was observed. It should be noted that groundwater levels vary seasonally with rainfall and other factors. Hydraulic Restrictive Layer The test pits were excavated to a total depth of 6.0 ft. There was no restrictive layer or hardpan clay at this depth. EPA Falling Head Infiltration Test Infiltration tests were conducted at the site following the EPA Falling Head test methodology. Data from all three (3) test pits were analyzed. The most limiting measured percolation rate was 1.0 inches/hour. Subsurface Soil Data A representative soil sample was collected near the grade of the proposed BMP bottom layer which was analyzed by Northwest Agricultural Consultants, Inc. on March 11, 2020. The soils encountered at 3 to 4 feet below grade in the proposed infiltration area are consistent with sandy loam classification based on the sieve analysis, as summarized in the attached lab results. Figure 3 contains a representative soil log. THE CONCEPT GROUP DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331 B 10814 Southeast 173rd Street Page 3 of 3 Depth (FT) Sample USC5 Graphic description 0.0 1 =_____= topsoil 0.5 1.0 1.5 tan sand with some gravel, no mottling or 2 5P 2.0 water seepage 2.5 3.0 3.5 f'sss'sss 4.0 f} 's compacted gray sand with some gravel, no 4.5 3 5M f mottling or water seepage 5.0 fsss'sss 5.5 6.0fffffff Figure 3 — Representative Soils Log (Not -to -Scale) Limitations The conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our exploration and assume that the soil and groundwater conditions encountered in the test pits are representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated soil conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking soil samples in test pits. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly constructed project. This report has been prepared for the exclusive use of the property owner and its representatives for specific application to this project and site. Our recommendations and conclusions are based on observed site materials and engineering analyses. Our conclusions and recommendations are professional opinions derived in accordance with current standards of practice within the scope of our services and within budget and time constraints. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in stormwater design. THE CONCEPT GROUP DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331 B Northwest Agricultural The Concept Group Consultants 4701 SW Admiral Way STE 353 460 Seattle, WA 98116 2545 W Falls Avenue PAP -Accredited Kennewick, WA 99336 509.783.7450 Report: 51021-1-2 Date: March 11, 2020 www.nwag.com Project No: lab@nwag.com Ji Project Name: 10814 SE 173rd St. Sample ID Moisture Organic Matter Cation Exchange Capacity PIT B 15.83% by weight 2.42% 7.7 meq/100g Gravimetric ASTM D2974 EPA 9081 Sample ID Sand Silt Clay Texture Class PIT B 61.0% 34.0% 5.0% Sandy Loam Sieve No. Diameter (mm) Passing (%) 4 4.75 91.6 40 0.425 67.2 60 0.250 54.5 DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331 B Northwest Agricultural The Concept Group Consultants 4701 SW Admiral Way STE 353 460 Seattle, WA 98116 2545 W Falls Avenue PAP -Accredited Kennewick, WA 99336 509.783.7450 Report: 51021-2-2 Date: March 11, 2020 www.nwag.com Project No: lab@nwag.com Ji Project Name: 10814 SE 173rd St. Sample ID Moisture Organic Matter Cation Exchange Capacity PIT A 13.05% by weight 1.14% 5.7 meq/100g Gravimetric ASTM D2974 EPA 9081 Sample ID Sand Silt Clay Texture Class PIT A 66.0% 30.0% 4.0% Sandy Loam Sieve No. Diameter (mm) Passing (%) 4 4.75 96.9 40 0.425 72.9 60 0.250 59.0 DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331B Project Address: 10814 SE 173rd Street (PIT A) Date: March 8, 2020 Infiltration Rate Calculation (per 2016 KCSWM 5.2.1) Assumptions: Step # 1: Measured percolation Rate time interval= A100 minutes water level drop = inches percolation rate: minutes/inch percolation rate:inch/hour Step # 2: Calculate design infiltration rate (Idesign) I design = Imeasured x Ftesting x Fgeometry x Fplugging Where: Imeasured = infiltration rate measured in the field Ftesting = 0.30 for EPA Falling Head Method, 0.50 for Small -Scale Pilot Test Fgeometry = (4D)/W +0.05 Where: D = depth from the bottom of the proposed facility to the maximum wet -season water table or nearest impervious layer, which ever is less W = width of facility Fplugging = 0.7 for loams and sandy Ioams = 0.8 for fine sands and loamy sands = 0.9 for medium sands = 1.0 for coarse sands or cobbles, or any soil type in an infiltration facility preceded by a water quality facility Imeasured - 1.00 inch/hour Ftesting = 0.30 per EPA Falling Head Method Fgeometry = 1.55 assumed D = 0.75 ft, W = 2.0 ft Fplugging = 0.70 sandy Ioams Idesign - 0.3 inch/hour DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331B Project Address: 10814 SE 173rd Street (PIT 8) Date: March 8, 2020 Infiltration Rate Calculation (per 2016 KCSWM 5.2.1) Assumptions: Step # 1: Measured percolation Rate time interval= minutes water level drop =Edinch/hour inches percolation rate: minutes/inch percolation rate: Step # 2: Calculate design infiltration rate (Idesign) Idesign = Imeasured x Ftesting x Fgeometry x Fplugging Where: Imeasured = infiltration rate measured in the field Ftesting = 0.30 for EPA Falling Head Method, 0.50 for Small -Scale Pilot Test Fgeometry = (4D)/W +0.05 Where: D = depth from the bottom of the proposed facility to the maximum wet -season water table or nearest impervious layer, which ever is less W = width of facility Fplugging = 0.7 for loams and sandy Ioams = 0.8 for fine sands and loamy sands = 0.9 for medium sands = 1.0 for coarse sands or cobbles, or any soil type in an infiltration facility preceded by a water quality facility Imeasured - 1.50 inch/hour Ftesting = 0.30 per EPA Falling Head Method Fgeometry = 1.55 assumed D = 0.75 ft, W = 2.0 ft Fplugging = 0.70 sandy Ioams Idesign — 0.5 inch/hour DocuSign Envelope ID: 922A5043-8263-48E6-9A5B-F7087123331B Project Address: 10814 SE 173rd Street (PIT C) Date: March 8, 2020 Infiltration Rate Calculation (per 2016 KCSWM 5.2.1) Assumptions: Step # 1: Measured percolation Rate time interval= A100 minutes water level drop = inches percolation rate: minutes/inch percolation rate:inch/hour Step # 2: Calculate design infiltration rate (Idesign) I design = Imeasured x Ftesting x Fgeometry x Fplugging Where: Imeasured = infiltration rate measured in the field Ftesting = 0.30 for EPA Falling Head Method, 0.50 for Small -Scale Pilot Test Fgeometry = (4D)/W +0.05 Where: D = depth from the bottom of the proposed facility to the maximum wet -season water table or nearest impervious layer, which ever is less W = width of facility Fplugging = 0.7 for loams and sandy Ioams = 0.8 for fine sands and loamy sands = 0.9 for medium sands = 1.0 for coarse sands or cobbles, or any soil type in an infiltration facility preceded by a water quality facility Imeasured - 1.00 inch/hour Ftesting = 0.30 per EPA Falling Head Method Fgeometry = 1.55 assumed D = 0.75 ft, W = 2.0 ft Fplugging = 0.70 sandy Ioams Idesign - 0.3 inch/hour 45 we . t, (2) King County Area, Washington (WAG33) King County Area, Washington (WA633) Map Acres percent Unit Map Unit Name in of AaI Symbol ADI AmC Arents, AlderV15 1.1 100.0°Io material, 6 tercent slo Totals for Area of 1.1 100.00l0 Interest 47 t Unit E —Xi Printable Version) Report — Map Unit Description Ding County Area, Washington AmC—Arents, Alderwood material, 5 to 15 percent slopes Map Unit Setting National map unit symbol: I h m s q Elevation: 50 to 660 feet Mean annual precipitation: 35 to 60 inches Mean annual air temperature: 50 degrees F Frost -free period: 150 to 200 days Farmland classification: Not prime farmland Map Unit Composition Arents, alderwuod material, and similar soils: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Arents, Alderwood Material Setti ng Landform: Till plains Parent material: Basal till Typical profile N1 - 4 to 26 inches: gravelly sandy loam Fit - 26 to 60 inches: very gravelly sandy loam Properties and qualities SIO.De: 6 to 1 s perCerlt Depth to rest;-crjve feature: 20 to 40 inches to densic material Natural drainage class: Moderately well drained Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table: About 16 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Very low (about 2.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: B/D Hydric soil rating: No Appendix E Bond Quantities Worksheet C3 Q) 1 Q m W W U) (A a oD 4- O L~ r G LL ( C Q Z O Iz Z Z W I'll W O G w > � a � �° Lr)O O�/ Y� a o Ln `W r a a z O U F- V) z O u cr O LL O a ci Of of v w w i O rz w w a cn Ln z 06 06 a) ui ui a a Y Y a C O w W w w to u U 3 N Ln Vt a w 0o O O v Ln E ,at >_ O ++ 00 C M i GJ T V) Ol C 4+ LAa, O C 3 z Q v 4a 00 j 00 G! 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W N 4J N 4J N 41 N� Ln l0 I- m O O- v C 0— w 3 w 3 0_ a Q a O_ a Q d ai ai ai ai ai O rn Q 0 O_ a 0 (3) (I) N N OOOOO U� v Y C vOi N N U1 O L L L L -0-2 3 3 3 3 oa o0 oa o0 oa 0� 3 U(D(7 l7 cncn cn cn cn cn�����aO _Q �cnJ e J 0 F 0 a W w w Ln N � Q z LA 2 W H Ln N O W ci 00 0) I� n V M o0 l0 M Q1 V 7 � h «Q = z u O o m W Ql V � z = Q a z al ° W I- x 10 Y z m v zo QaC W M L = wo 0 a M x L o i--I cc ,� O 00 e^-I o N Z0 a m o vi o vri s = o 000 V W -- o 0 e�i 00 o w O Z M 14 00 M V 00 0 v n n ZT M N o M M o0 M G� N a cn zr Q N V L Q 0 y 6 LL G y a a Q y m° F LL V V in a a z O c G Q v3i Q N z N m z a O a0+ 7 O z O O O o O X V N 00 00 00 m a d u U a N o o ai O a O ns Ln v M J 2 C P E h a z_ L N > n _ a � lYo N �% of iz m ti o n U v O °c_ a o a 0 3 00 co l0 S a a Ln oN ca 0. v y o O E w -+, 0 Q C :Z Oi , C C N m LL cc O O c E E E a c 3 m 00 O a 3 p C x W O �n C a z \ c o n E m c 0 o N 0) R obD 0 0 0 0 E -6 o L v ° c ° 3 •m Z v ¢ Zo Q Y`o v v 3 c v c `5 ac .z v o c a; Qj E y ai c— z E o "c � "o cc V a ��. a5 W L E +-'X 3 O O N O N +�-' O 0 Z LL 11 11 LL W {n W LL N m 0: m D; N V Gc� G m U Appendix F Declaration of Covenant EXHIBIT A - FLOW CONTROL BMP SITE PLAN 12" DI SD I I 10+00 I I — LJ SE 173RD STREET 117 - APPROVED BY: S. r r Y r l �,' TITTLE: NGOCHAN SHORT PLAT 11+00 HORIZONTAL GRAPHIC SCALE 10 5 0 5 10 1 inch = 20 ft. SCALE: 1 "_20- DATE: 4-15-2020 EXHIBIT B - MAINTENANCE INSTRUCTIONS FOR LIMITED INFILTRATION YOUR PROPERTY CONTAINS AN ON -SITE BMP (BEST MANAGEMENT PRACTICE) CALLED "LIMITED INFILTRATION," WHICH WAS INSTALLED TO MITIGATE THE STORMWATER QUANTITY AND QUALITY IMPACTS OF SOME OR ALL OF THE IMPERVIOUS SURFACES ON YOUR PROPERTY. LIMITED INFILTRATION IS A METHOD OF SOAKING RUNOFF FROM IMPERVIOUS AREAS\ (SUCH AS PAVED AREAS AND ROOFS) INTO THE GROUND. IF PROPERLY INSTALLED AND MAINTAINED PER APPENDIX A OF THE CITY OF RENTON'S SURFACE WATER DESIGN MANUAL, LIMITED INFILTRATION CAN MANAGE RUNOFF SO THAT A MAJORITY OF PRECIPITATION EVENTS ARE ABSORBED. INFILTRATION DEVICES, SUCH AS GRAVEL FILLED TRENCHES, DRYWELLS, AND GROUND SURFACE DEPRESSIONS, FACILITATE THIS PROCESS BY PUTTING RUNOFF IN DIRECT CONTACT WITH THE SOIL AND HOLDING THE RUNOFF LONG ENOUGH TO SOAK MOST OF IT INTO THE GROUND. TO BE SUCCESSFUL, THE OIL CONDITION AROUND THE INFILTRATION DEVICE MUST BE RELIABLY ABLE TO SOAK WATER INTO THE GROUND FOR A REASONABLE NUMBERS OF YEARS. INFILTRATION DEVICES THE DISPERSION DEVICES USED ON YOUR PROPERTY INCLUDE THE FOLLOWING AS INDICATED ON THE SITE PLAN: ® ❑ ❑ GRAVEL FILLED TRENCHES, DRYWELLS, GROUND SURFACE DEPRESSIONS. MAINTENANCE RESTRICTIONS THE SIZE, PLACEMENT, AND COMPOSITION OF THESE DEVICES ARE DEPICTED BY THE SITE PLAN AND DESIGN DETAILS MUST BE MAINTAINED AND MAY NOT BE CHANGED WITHOUT WRITTEN APPROVAL FROM THE CITY OF RENTON OR A THROUGH A FUTURE DEVELOPMENT PERMIT FROM THE CITY OF RENTON. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES • INFILTRATION DEVICES MUST BE INSPECTED ANNUALLY AND AFTER MAJOR STORM EVENTS TO IDENTIFY AND REPAIR AND PHYSICAL DEFECTS. • MAINTENANCE AND OPERATION OF THE SYSTEM SHOULD FOCUS ON ENSURING THE SYSTEM'S VIABILITY BY PREVENTING SEDIMENT -LADEN FLOWS FROM ENTERING THE DEVICE. EXCESSIVE SEDIMENTATION WILL RESULT IN A PLUGGED OR NON-FUNCTIONING FACILITY. • IF THE INFILTRATION DEVICE HAS A CATCH BASIN, SEDIMENT ACCUMULATION MUST BE REMOVED ON A YEARLY BASIS OR MORE FREQUENTLY IF NECESSARY. KEEPING THE AREAS THAT DRAIN TO INFILTRATION DEVICES WELL SWEPT AND CLEAN WILL ENHANCE THE LONGEVITY OF THESE AREAS FOR ROOFS, FREQUENT CLEANING OF GUTTERS WILL REDUCE SEDIMENT LOADS ON THESE DEVICES. PUBLIC WORKS FLOW CONTROL BMP DETAILS DEPARTMENT DATE: 4-15-2020 50 Appendix G WWHM Report WWHM2012 PROJECT REPORT General Model Information Project Name: Ngochan SP Peak Flows 2020.04.28 Site Name: Site Address: City: Report Date: 10/16/2020 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2019/09/03 Version: 4.2.16 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:25 AM Page 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass: No Groundwater: No Pervious Land Use acre C, Forest, Flat 0.26 Pervious Total 0.26 Impervious Land Use acre Impervious Total 0 Basin Total 0.26 Element Flows To: Surface Interflow Groundwater Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:25 AM Page 3 Mitigated Land Use Basin 1 Bypass: No Groundwater: No Pervious Land Use acre C, Lawn, Flat 0.08 Pervious Total 0.08 Impervious Land Use acre ROADS FLAT 0.18 Impervious Total 0.18 Basin Total 0.26 Element Flows To: Surface Interflow Groundwater Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:25 AM Page 4 Routing Elements Predeveloped Routing Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:25 AM Page 5 Mitigated Routing Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:26 AM Page 6 Analysis Results POC 1 w 0.0, U 0.01 0 0.0 Percent Time E�cceedir+g 0 Y.S 1 i + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.26 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.08 Total Impervious Area: 0.18 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.007644 5 year 0.012006 10 year 0.014477 25 year 0.017096 50 year 0.018716 100 year 0.020094 Flow Frequency Return Periods for Mitigated Return Period Flow(cfs) 2 year 0.073753 5 year 0.095149 10 year 0.109924 25 year 0.129336 50 year 0.144362 100 year 0.159888 Annual Peaks Annual Peaks for Predeveloped and Mitigated Year Predeveloped Mitigated 1949 0.008 0.100 1950 0.009 0.098 1951 0.017 0.063 1952 0.005 0.050 1953 0.004 0.054 1954 0.007 0.060 1955 0.011 0.067 1956 0.008 0.066 1957 0.007 0.078 1958 0.008 0.060 POC #1 POC #1 Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:26:26 AM Page 7 1959 0.007 0.058 1960 0.011 0.065 1961 0.006 0.066 1962 0.004 0.054 1963 0.005 0.064 1964 0.007 0.060 1965 0.005 0.081 1966 0.005 0.051 1967 0.010 0.090 1968 0.006 0.102 1969 0.006 0.074 1970 0.005 0.069 1971 0.006 0.082 1972 0.013 0.092 1973 0.006 0.048 1974 0.006 0.077 1975 0.008 0.080 1976 0.006 0.059 1977 0.001 0.059 1978 0.005 0.073 1979 0.003 0.099 1980 0.012 0.104 1981 0.005 0.076 1982 0.009 0.111 1983 0.008 0.085 1984 0.005 0.056 1985 0.003 0.077 1986 0.013 0.064 1987 0.012 0.098 1988 0.005 0.058 1989 0.003 0.073 1990 0.025 0.152 1991 0.015 0.116 1992 0.006 0.055 1993 0.006 0.046 1994 0.002 0.048 1995 0.008 0.067 1996 0.018 0.077 1997 0.015 0.073 1998 0.003 0.069 1999 0.014 0.152 2000 0.006 0.074 2001 0.001 0.076 2002 0.006 0.099 2003 0.008 0.077 2004 0.011 0.141 2005 0.008 0.065 2006 0.009 0.058 2007 0.018 0.136 2008 0.023 0.114 2009 0.012 0.089 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0245 0.1524 2 0.0235 0.1522 3 0.0182 0.1412 Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 8 4 0.0179 0.1360 5 0.0168 0.1165 6 0.0150 0.1144 7 0.0148 0.1111 8 0.0140 0.1037 9 0.0132 0.1023 10 0.0125 0.1005 11 0.0119 0.0992 12 0.0117 0.0990 13 0.0115 0.0983 14 0.0114 0.0979 15 0.0107 0.0915 16 0.0105 0.0897 17 0.0104 0.0889 18 0.0094 0.0852 19 0.0091 0.0823 20 0.0091 0.0815 21 0.0085 0.0802 22 0.0084 0.0783 23 0.0084 0.0773 24 0.0083 0.0769 25 0.0082 0.0767 26 0.0077 0.0765 27 0.0076 0.0763 28 0.0075 0.0761 29 0.0072 0.0740 30 0.0067 0.0737 31 0.0066 0.0735 32 0.0065 0.0730 33 0.0065 0.0726 34 0.0065 0.0692 35 0.0064 0.0689 36 0.0063 0.0672 37 0.0062 0.0669 38 0.0061 0.0662 39 0.0059 0.0659 40 0.0059 0.0648 41 0.0057 0.0648 42 0.0057 0.0642 43 0.0056 0.0638 44 0.0055 0.0625 45 0.0053 0.0601 46 0.0053 0.0598 47 0.0052 0.0597 48 0.0052 0.0593 49 0.0051 0.0585 50 0.0050 0.0584 51 0.0047 0.0582 52 0.0046 0.0581 53 0.0043 0.0557 54 0.0040 0.0552 55 0.0034 0.0543 56 0.0032 0.0543 57 0.0030 0.0515 58 0.0030 0.0503 59 0.0020 0.0485 60 0.0011 0.0477 61 0.0007 0.0463 Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 9 Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 10 Duration Flows Flow(cfs) Predev Mit Percentage Pass/Fail 0.0038 17547 115371 657 Fail 0.0040 16164 112013 692 Fail 0.0041 14970 108719 726 Fai 1 0.0043 13851 105618 762 Fai 1 0.0044 12816 102645 800 Fai 1 0.0046 11809 99843 845 Fail 0.0047 10900 97041 890 Fail 0.0049 10119 94410 932 Fail 0.0050 9383 91929 979 Fail 0.0052 8729 89512 1025 Fail 0.0053 8145 87095 1069 Fail 0.0055 7593 84742 1116 Fail 0.0056 7060 82454 1167 Fail 0.0058 6590 80336 1219 Fail 0.0059 6145 78326 1274 Fai 1 0.0061 5777 76315 1321 Fail 0.0062 5431 74412 1370 Fail 0.0064 5097 72572 1423 Fai 1 0.0065 4808 70776 1472 Fai 1 0.0067 4524 69000 1525 Fai 1 0.0068 4254 67311 1582 Fai 1 0.0070 4017 65685 1635 Fai 1 0.0071 3784 64081 1693 Fai 1 0.0073 3546 62541 1763 Fai 1 0.0074 3337 61044 1829 Fai 1 0.0076 3138 59653 1900 Fai 1 0.0077 2952 58220 1972 Fai 1 0.0079 2785 56787 2039 Fai 1 0.0080 2599 55418 2132 Fail 0.0082 2447 54092 2210 Fail 0.0083 2304 52873 2294 Fai 1 0.0085 2160 51654 2391 Fai 1 0.0086 2024 50456 2492 Fail 0.0088 1898 49323 2598 Fail 0.0089 1790 48146 2689 Fai 1 0.0091 1687 46991 2785 Fai 1 0.0092 1583 45900 2899 Fai 1 0.0094 1483 44874 3025 Fail 0.0095 1380 43890 3180 Fail 0.0097 1292 42927 3322 Fail 0.0098 1219 41922 3439 Fail 0.0100 1154 40981 3551 Fail 0.0101 1098 40040 3646 Fail 0.0103 1048 39099 3730 Fail 0.0104 997 38200 3831 Fail 0.0106 930 37366 4017 Fail 0.0107 884 36511 4130 Fai 1 0.0109 838 35719 4262 Fail 0.0110 789 34864 4418 Fail 0.0112 743 34158 4597 Fai 1 0.0113 713 33431 4688 Fai 1 0.0115 670 32703 4881 Fai 1 0.0116 633 31998 5054 Fai 1 0.0118 596 31313 5253 Fai I Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 11 0.0119 567 30629 5401 Fail 0.0121 540 29944 5545 Fail 0.0122 497 29324 5900 Fai 1 0.0124 474 28725 6060 Fai 1 0.0125 437 28083 6426 Fai 1 0.0127 401 27527 6864 Fail 0.0128 370 26971 7289 Fail 0.0130 348 26394 7584 Fail 0.0131 324 25816 7967 Fai 1 0.0133 296 25217 8519 Fai 1 0.0135 272 24704 9082 Fai 1 0.0136 256 24148 9432 Fail 0.0138 235 23635 10057 Fai 1 0.0139 217 23143 10664 Fai 1 0.0141 195 22651 11615 Fai 1 0.0142 180 22180 12322 Fai 1 0.0144 158 21710 13740 Fai 1 0.0145 145 21263 14664 Fail 0.0147 129 20852 16164 Fail 0.0148 119 20407 17148 Fai 1 0.0150 109 20009 18356 Fai 1 0.0151 97 19616 20222 Fai 1 0.0153 91 19229 21130 Fai 1 0.0154 82 18846 22982 Fai 1 0.0156 76 18439 24261 Fai 1 0.0157 69 18082 26205 Fai 1 0.0159 61 17736 29075 Fai 1 0.0160 55 17404 31643 Fail 0.0162 48 17079 35581 Fail 0.0163 41 16728 40800 Fail 0.0165 38 16397 43150 Fai 1 0.0166 33 16031 48578 Fai 1 0.0168 27 15708 58177 Fail 0.0169 22 15368 69854 Fail 0.0171 21 15071 71766 Fai 1 0.0172 20 14788 73940 Fai 1 0.0174 19 14510 76368 Fai 1 0.0175 17 14256 83858 Fail 0.0177 14 13984 99885 Fail 0.0178 12 13725 114375 Fai 1 0.0180 9 13483 149811 Fai 1 0.0181 4 13253 331325 Fai 1 0.0183 3 13004 433466 Fai 1 0.0184 3 12741 424700 Fai 1 0.0186 3 12521 417366 Fai 1 0.0187 3 12299 409966 Fai I The development has an increase in flow durations from 1 /2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 12 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 13 LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Waterfluality Percent Comment Treatment? Needs Through Volume Volume Volume WaterQuality Treatment Facility (ac-ft) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Total Volume Infiltrated 0.00 0.00 0.00 0.00 OM 0% No Treat. Credit Duration Compliance with LID Analysis Standard 0% of2-yrto 50% of Result = 2 yr Failed Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:08 AM Page 14 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:40 AM Page 15 Appendix Predeveloped Schematic a Basin 1 ,. 0.25ac LA Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:40 AM Page 16 Mitigated Schematic Basin 1 „ 0.25ac Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 17 Predeveloped UC/ File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <----------- File Name ------------------------------ >*** <-ID-> *** WDM 26 Ngochan SP Peak Flows 2020.04.28.wdm MESSU 25 PreNgochan SP Peak Flows 2020.04.28.MES 27 PreNgochan SP Peak Flows 2020.04.28.L61 28 PreNgochan SP Peak Flows 2020.04.28.1,62 30 POCNgochan SP Peak Flows 2020.04.281.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<---------- Title ----------- >***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><------- Name---- 10 C, Forest, Flat END GEN-INFO *** Section PWATER*** ->NBLKS Unit -systems Printer *** User t-series Engl Metr *** in out *** 1 1 1 1 27 0 ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT -INFO <PLS > ***************** Print -flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT -INFO Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 18 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATEI <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATEI END PERLND IMPLND GEN-INFO <PLS ><------- Name ------- > Unit -systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT -INFO <ILS > ******** Print -flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT -INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATEI <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATEI Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 19 END IMPLND SCHEMATIC <-Source-> <Name> # Basin 1*** PERLND 10 PERLND 10 ******Routing****** END SCHEMATIC <--Area--> <-Target-> MBLK <-factor-> <Name> # Tbl# 0.26 COPY 501 12 0.26 COPY 501 13 NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------ >< --- > User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT -INFO <PLS > ***************** Print -flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT -INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------ ><-------- ><-------- ><-------- ><-------- ><-------- ><-------- > *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------ ><-------- > <--- ><--- ><--- ><--- >< --- > *** <--- ><--- ><--- ><--- >< --- > END HYDR-INIT END RCHRES SPEC -ACTIONS END SPEC -ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 20 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS -LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS -LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS -LINK 12 MASS -LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS -LINK 13 END MASS -LINK END RUN Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 21 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <----------- File Name ------------------------------ >*** <-ID-> *** WDM 26 Ngochan SP Peak Flows 2020.04.28.wdm MESSU 25 MitNgochan SP Peak Flows 2020.04.28.MES 27 MitNgochan SP Peak Flows 2020.04.28.L61 28 MitNgochan SP Peak Flows 2020.04.28.1,62 30 POCNgochan SP Peak Flows 2020.04.281.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<---------- Title ----------- >***TRAN PIVL DIG1 FIL1 1 Basin 1 MAX END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO PYR DIG2 FIL2 YRND 1 2 30 9 <PLS ><------- Name ------- >NBLKS Unit -systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT -INFO <PLS > ***************** Print -flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT -INFO Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 22 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATEI <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATEI END PERLND IMPLND GEN-INFO <PLS ><------- Name ------- > Unit -systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT -INFO <ILS > ******** Print -flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT -INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 23 END IWAT-PARM3 IWAT-STATEI <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATEI END IMPLND SCHEMATIC <-Source-> <Name> # Basin 1*** PERLND 16 PERLND 16 IMPLND 1 ******Routing****** END SCHEMATIC <--Area--> <-Target-> MBLK <-factor-> <Name> # Tbl# 0.08 COPY 501 12 0.08 COPY 501 13 0.18 COPY 501 15 NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------ >< --- > User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT -INFO <PLS > ***************** Print -flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT -INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC Al A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------ ><-------- ><-------- ><-------- ><-------- ><-------- ><-------- > *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------ ><-------- > <--- ><--- ><--- ><--- >< --- > *** <--- ><--- ><--- ><--- >< --- > END HYDR-INIT END RCHRES SPEC -ACTIONS Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 24 END SPEC -ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS -LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <Name> <Name> # #<-factor-> <Name> MASS -LINK 12 PERLND PWATER SURO 0.083333 COPY END MASS -LINK 12 MASS -LINK 13 PERLND PWATER IFWO 0.083333 COPY END MASS -LINK 13 MASS -LINK 15 IMPLND IWATER SURO 0.083333 COPY END MASS -LINK 15 END MASS -LINK END RUN <-Grp> <-Member->*** <Name> # #*** INPUT MEAN INPUT MEAN INPUT MEAN Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 25 Predeveloped HSPF Message File Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 26 Mitigated HSPF Message File Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 27 Disclaimer Legal Notice This program and accompanying documentation are provided 'as -is' without warranty of any kind. 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Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Ngochan SP Peak Flows 2020.04.28 10/16/2020 11:27:41 AM Page 28