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HomeMy WebLinkAboutTIR-4255 FINAL TECHNICAL INFORMATION REPORT FOR Towns on 12th CITY OF RENTON, WASHINGTON 09/05/2023 Prepared by: Andrew Oh, E.I.T., Katie Lane, E.I.T. Approved by: Holli Heavrin, P.E. Date: 4/27/2023 Revised: 09/05/2023 Core No.: 21008 SURFACE WATER UTILITY jfarah 12/06/2023 DEVELOPMENT ENGINEERING yqi 12/06/2023 Core Design, Inc. TOWNS ON 12TH i TOWNS ON 12TH Table of Contents 1. PROJECT OVERVIEW .......................................................................................................................... 1-1 2. CONDITIONS AND REQUIREMENTS SUMMARY ................................................................................ 2-2 2.1 Core Requirements .......................................................................................................................... 2-3 2.1.1 Core Requirement #1: Discharge at the Natural Location ...................................................... 2-3 2.1.2 Core Requirement #2: Offsite Analysis .................................................................................... 2-3 2.1.3 Core Requirement #3: Flow Control......................................................................................... 2-3 2.1.4 Core Requirement #4: Conveyance System ............................................................................. 2-3 2.1.5 Core Requirements #5: Erosion and Sediment Control ........................................................... 2-3 2.1.6 Core Requirement #6: Maintenance and Operations .............................................................. 2-3 2.1.7 Core Requirement #7: Financial Guarantees and Liability ....................................................... 2-3 2.1.8 Core Requirement #8: Water Quality ...................................................................................... 2-5 2.1.9 Core Requirement #9: On-Site BMPs ....................................................................................... 2-6 2.2 Special Requirements ...................................................................................................................... 2-6 2.2.1 Special Requirement #1: Other Adopted Area Specific Requirements .................................... 2-6 2.2.2 Special Requirement #2: Flood Hazard Area Delineation ........................................................ 2-6 2.2.3 Special Requirement #3: Flood Protection Facilities ................................................................ 2-6 2.2.4 Special Requirement #4: Source Control ................................................................................. 2-6 2.2.5 Special Requirement #5: Oil Control ........................................................................................ 2-6 2.2.6 Special Requirement #6: Aquifer Protection Area ................................................................... 2-6 3. OFFSITE ANALYSIS ............................................................................................................................. 3-1 3.1 Resource Review .............................................................................................................................. 3-1 3.1.1 Sensitive Areas ......................................................................................................................... 3-1 3.2 Field Investigation ............................................................................................................................ 3-4 4. FLOW CONTROL AND WATER QUALITY DESIGN ............................................................................... 4-7 4.1 Hydraulic Analysis ............................................................................................................................ 4-7 4.1.1 Existing Conditions ................................................................................................................. 4-10 4.1.2 Upstream Conditions.............................................................................................................. 4-10 4.1.3 Developed Conditions ............................................................................................................ 4-12 4.1.4 NE Sunset Blvd Sidewalk Analysis .......................................................................................... 4-21 Core Design, Inc. TOWNS ON 12TH ii 4.2 Water Quality Treatment Analysis and Design .............................................................................. 4-23 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ................................................................................. 5-1 6. SPECIAL REPORTS AND STUDIES ....................................................................................................... 6-1 7. OTHER PERMITS ................................................................................................................................ 7-1 8. ESC ANALYSIS AND DESIGN ............................................................................................................... 8-1 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ............................. 9-1 9.1 Bond Quantities ............................................................................................................................... 9-1 9.2 Facility Summaries ........................................................................................................................... 9-1 9.3 Declaration of Covenant .................................................................................................................. 9-1 10. OPERATIONS AND MAINTENANCE .................................................................................................. 10-1 Core Design, Inc. TOWNS ON 12TH Page 1-1 1. PROJECT OVERVIEW The proposed Towns on 12th project is located to the north of the intersection of NE 12th Street and NE 11th Place Renton, Washington within Section 4, Township 23 North, Range 5 East, W.M. See Vicinity Map below. The site is composed of seven parcels #042305-9063, #042305-9099, #042305-9067, #042305-9140, #042305-9100, #042305-9101 and #032405-9247 with an area of approximately 6.55 acres. The site is bordered by NE Sunset Blvd. (which is a major arterial) to the north, NE 12th Street (collector) to the south, residential developed parcels to the west, and commercial developed parcels to the east. The site has a high point in the middle of the site and slopes down in all directions ranging from 5-20%. Proposed development of the property will include the construction of multiple townhomes, private roads, utilities, and minor frontage improvements. All existing structures and hard surfaces will be demolished and removed. The subject project’s drainage facilities were designed using the guidelines and requirements established in the 2022 City of Renton Surface Water Design Manual (RSWDM). Flow Control Duration Standard (Matching Forested) and Enhanced Basic Water Quality Treatment are required for this project. Core Design, Inc. TOWNS ON 12TH Page 2-2 2. CONDITIONS AND REQUIREMENTS SUMMARY The proposed project is classified as requiring “Full Drainage Review” per the 2022 RSWDM. Therefore, all nine core requirements and six special requirements will be addressed per Section 1.2 and 1.3 of the 2022 RSWDM. Core Design, Inc. TOWNS ON 12TH Page 2-3 2.1 Core Requirements 2.1.1 Core Requirement #1: Discharge at the Natural Location The project discharges its drainage at the natural location which is to the City’s conveyance system located along the south side of NE Sunset Blvd. 2.1.2 Core Requirement #2: Offsite Analysis See Section 3 of this Report for the downstream analysis. 2.1.3 Core Requirement #3: Flow Control The site falls within the City’s Flow Control Duration Standard (Matching Forested). See City’s Flow Control Application Map on the following page. This flow control standard requires matching forested conditions over the range of flows extending from 50% of 2-year up to the full 50-year flow AND matches peaks for the 2- and 10-year return periods. See Section 4 of this Report for details on the Flow Control Analysis. 2.1.4 Core Requirement #4: Conveyance System Analysis of the proposed conveyance system has been run in order to confirm capacity. See Section 5 for a discussion of the analysis and results. 2.1.5 Core Requirements #5: Erosion and Sediment Control To prevent sediment transport and pollutant discharges, as well as other impacts related to land- disturbing construction activities, ESC measures and Stormwater Pollution Prevention and Spill Control (SWPPS) measures that are appropriate to the project site must be applied through a comprehensive Construction Stormwater Pollution Prevention (CSWPP) plan. A CSWPP plan has been prepared for the project and has been submitted under separate cover. See Section 8 for additional details. 2.1.6 Core Requirement #6: Maintenance and Operations This project will provide a Maintenance and Operations manual to ensure that the maintenance responsibility for drainage facilities is clearly assigned and that these facilities will be properly maintained and operated in perpetuity. See Section 10 for details relating to the operations and maintenance manual. 2.1.7 Core Requirement #7: Financial Guarantees and Liability See Section 9 for information regarding the financial guarantees and liability for this project. Lake Desire Shady Lake (Mud Lake) Panther Lake LakeYoungs Lake Washington B l a ck Ri ve r Gr ee n Riv e r Ce darRi v erUV900 UV167 UV515 UV169 UV900 UV169 UV167BN IncBN IncBBNNIInnccSSEERReennttoonnIIssssaaqquuaahh RR dd RReennttoonnMMaapplleeVVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEESSWW SSuunnsseettBBllvvdd RRaaii nnii eerr AAvveeNNNE 3rd St NE 3rd S t SW 43rd StSW 43rd St SSEE CCaarrrrRR dd NE 4th StNE 4th St SSEERReennttoonn MMaappllee VVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNNEE DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 167114400tthh WWaayySS EE NNEE2277tthhSStt 115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St N 8th StN 8th St PP uuggeettDDrrSSEE RR ee nnttoonnAAvvee SS SSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEESE 128th StSE 128th St II nntt eerr uurr bbaannAAvveeSS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeett rr oovviitt sskkyyRRddEEVVaalllleeyyHHwwyySE 192nd StSE 192nd St SE 60th StSE 60th St TTaallbboottRRddSSRR ee nntt oo nn AAvveeSS116644tthhAAvveeSSEESE 208th StSE 208th St SE 72nd StSE 72nd St RRaaiinniieerrAAvvee SS 111166tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS118800tthh SStt CCooaall CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St 114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBee aa ccoonn AA vv ee SS FFoorreesstt DDrr SSEE SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEE MMaayy VVaalllleeyyRRdd SS EE JJoonneess RRdd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SE 144th StSE 144th St 114488tthhAAvveeSSEE115544tthhPPllSSEELL aa kk ee WWaa sshhii nnggtt oonnBBll vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 ,§-405 μ 012Miles Flow Control Application Map Reference 1-A Date: 01/09/2014 Flow Control Standards Peak Rate Flow Control Standard (Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) Flow Control Duration Standard (Forested Conditions) Flood Problem Flow Unincorporated King County Flow Control Standards Renton City Limits Potential Annexation Area PROJECT SITE Core Design, Inc. TOWNS ON 12TH Page 2-5 2.1.8 Core Requirement #8: Water Quality As the City of Renton does not have Sensitive Lake or Sphagnum Bog Water Quality Treatment Areas, Basic Water Quality Treatment is the only other option available. As the proposed project is a Multifamily Residential development, Enhanced Basic Water Quality Treatment is required. See Section 4 of this Report for details on Water Quality Facility Sizing. Core Design, Inc. TOWNS ON 12TH Page 2-6 2.1.9 Core Requirement #9: On-Site BMPs See Section 4.1.2 of this Report for discussion on how this Core Requirement is addressed. 2.2 Special Requirements 2.2.1 Special Requirement #1: Other Adopted Area Specific Requirements There are no known additional requirements for the subject project. 2.2.2 Special Requirement #2: Flood Hazard Area Delineation Not applicable since the project does not contain nor is adjacent to a flood hazard area. 2.2.3 Special Requirement #3: Flood Protection Facilities Not applicable since the project does not rely on an existing flood protection facility or plans to modify or construct a new flood protection facility. 2.2.4 Special Requirement #4: Source Control Not applicable since the project is not a commercial development. 2.2.5 Special Requirement #5: Oil Control Not applicable since the project is not a high use site. The expected average daily traffic is less than 100 vehicles per 1,000 square feet of gross building area. 2.2.6 Special Requirement #6: Aquifer Protection Area Not applicable since the project is not in an Aquifer Protection Area. Core Design, Inc. TOWNS ON 12TH Page 3-1 3. OFFSITE ANALYSIS 3.1 Resource Review The proposed project is located within the Lake Washington Cedar River Watershed. 3.1.1 Sensitive Areas Renton GIS was reviewed for sensitive areas. The proposed project site falls within the following sensitive areas: landslide and regulated slopes. The proposed project site does not fall within the following sensitive areas: coal mines, erosion hazard, flood hazard, floodway, channel migration zone, seismic hazard, regulated stream, or wellhead protection. Core Design, Inc. TOWNS ON 12TH Page 3-2 According to the Renton GIS Map, there is a portion of the site along the north boundary which falls within a landslide hazard area. See picture below. Landslide Hazard (Per Renton GIS Data) Core Design, Inc. TOWNS ON 12TH Page 3-3 According to the Renton GIS Map, there is a portion of the site along the north boundary which falls within 15%-90% regulated slope. See picture below. Regulated Slope: 15% to 90% Slope Area (Per Renton GIS Data) Core Design, Inc. TOWNS ON 12TH Page 3-4 3.2 Field Investigation A field investigation was completed on June 9, 2021. Upstream Tributary Analysis There is a neighborhood directly west of the project site. In this neighborhood there are three side roads that are located to the northwest of the project boundary that point towards the site: NE 14th Place, NE 14th Court, and NE 14th Street.. The southern-most road (NE 14th Street) slopes east towards the site, but has a mound and catch basin located at the low point of the road. This would prevent any runoff from this road from entering the project site. The other two roads slope west away from the project site. We will assume that the site’s western boundary acts as a high point for the purposes of the basin boundary. The rest of the homes located to the south of these three side roads drain directly into the existing detention pond located in this neighborhood. There is a storm system located in the backyard of these homes that will collect all backyard drainage and direct it to the detention pond as well. We can assume that this portion of the site’s western boundary is also a high point for the purposes of the basin boundary. There is additional upstream area to the site that is accounted for in the existing wetland located along the west boundary of the site. The area from four existing homes to the south of the wetland, drains to the wetland and discharges into the site. Along the south property line lies NE 12th Street. No runoff from NE 12th Street will enter the project site as there is an existing mound along the north edge of NE 12th Street that prevents any runoff from entering into the site. Downstream Drainage Complaints Drainage complaints were researched within a quarter mile of the project site. City of Renton does not list any current complaints along the project’s downstream route. Onsite Drainage System Description The site consists of seven connected parcels. The center of the project site contains a single-family residence and shed. A dirt roadway creates a passage between the west and east portions of the site which connects through the center of the site. There are two additional single-family homes in the southern portion of the site. The remainder of the site is undeveloped consisting of thick forest cover. The northwestern portion of the site contains a large meadow with thick grass cover. Large trees are found in abundance throughout the project site. The entire site is located within the May Creek drainage basin. The topography of the entire site generally slopes to the north. Steep slopes are found along the northern boundary of the parcel bordering NE Sunset Blvd. The site also contains steep slopes along the eastern boundary of the project site. These slopes lead downhill eastward towards the adjacent businesses on NE Sunset Blvd. These slopes lead to the existing stormwater collection system along the southern border of NE Sunset Blvd. The meadow in the northwestern region of the map is a localized Core Design, Inc. TOWNS ON 12TH Page 3-5 low point for site runoff. The slope is directed in a northeastern direction towards the adjacent road from this point. Downstream Drainage System Description Runoff travels over the site via sheet flow over thick forested ground cover. All flow onsite is eventually directed towards NE Sunset Blvd. which is located north of the site. An existing catch basin network along the southern boundary of NE Sunset Blvd. serves to collect runoff and continue the flow eastward (see downstream map). All the receiving catch basins north of site are located along the southern edge of NE Sunset Blvd. All runoff is directed to the point where it is conveyed across the highway and then directed northward into Honey Creek. Honey Creek flows northward and eventually joins May Creek beyond the ¼ mile extent of the analysis. At this point the downstream analysis is terminated. See downstream map for details. Downstream Reach Description to a quarter mile Pipe Material Pipe Diameter (in) Overall Length (ft) Cumulative Length (ft) Concrete 18 262 262 Concrete 18 55 317 Concrete 18 53 370 Unknown 18 47 417 Honey Creek N/A 1,273 1,320 Core Design, Inc. TOWNS ON 12TH Page 3-6 Core Design, Inc. TOWNS ON 12TH Page 4-7 4. FLOW CONTROL AND WATER QUALITY DESIGN A flow control facility is proposed as the project is required to meet the City’s Flow Control Duration Standard (Matching Forested). This flow control standard requires matching forested conditions over the range of flows extending from 50% of 2-year up to the full 50-year flow and matching peaks for the 2- and 10-year return periods. A water quality treatment facility is proposed as the project is required to provide enhanced basic water quality treatment as delineated in Section 4.2 of this Report. 4.1 Hydraulic Analysis The drainage analysis was modeled using WWHM. Per the City of Renton Soil Survey, the site soil is Alderwood (AgC), hydrologic soil group “C”, Till for modeling. BeD BeD BeC AkF AmC KpD AmB AmB AgC AgC AgC KpB AgC AkF BeD AgC KpD AgCKpBKpBAgD EvC Bh BeC AgB KpB AgD UrEwC EvB AmC Or AgC BeC BeD BeD BeC AgC KpD BeC KpCKpB Sk AmC BeC UrBeCUr AgD KpB Ur AgC EvC KpC AgC OvD SkAgB AgB AgD EvC W OvD OvD No AgC AgD EvC RdC Sk KpB No AgCRdEAgCEvC BeC InC Bh BeD RdC AkF AgD BeD BhSm AgC RdE AgC AgDEvC Sh Sh PITS PyAgC AgD AgC EvC PITS EvB BeC OvC PITS EvB AgC InA AgD AgD Ur Bh AgC RdCEvCEvD AmB AmC AgD BeD EvC AkF AgD AgC Sm AgD AmC EvB AgD Sm AgC EwC PITSPu Bh Bh AgC KpD Tu AgC EvC EvC Ur RdC KpB RdCRdE W AgD AgD No AgB AgC No An AkF EvB InD AgD EvDInC SkBeC PITS Ur WBeC W BeD An EvC BeC Pc EvC Rh AmC BeCBeD BeD Ur BeC Ur W W Rh EvC AkF PITS AgD AmCPITS Wo Py Tu BeD EvB Py AmC Py An InC Ng AgC AgC W EvB AgD AgCWo Ur W Ur RdC Ur Ur EvC Rh Pc PyPy AgD AmC AgD MaRh Pc BeD Py Ng AmC Ng BeC AgC Rh AgD Py Ma PyRh RhRhPu Pu Ur Pu PITS BeD Rh EvC Py Wo Wo AgC Ma AgD AgB So Ng AgD Tu Py AgC AgC AgC AgC Ng Ur AgD Sk AmB AgB AgD PuUr Py Sk Ur No AgB MaBeC W AkFBeDPu Py No No AmC AgC EvC Ma Sk EvC AgB Py InC SkAmC AmC AgC AgB SkAgBPITS AgC No Pu AmB EvC PITS AmB AgB AkF AkF Ng AgD AgD AgB EvBAmB AmC AmC Wo Ng PITS Nk AgD SkNk SkAgB Ur AgD Wo AmC No AgD No Ur AgB Ur Br Py Os So EvB Ur Nk Wo AmB W Pc OsRe UrAmB Sk W AmC Tu No Pu AgD AmBAkFAgCNo UrPk AgB AgC Ur AmB NoAmC NoAmC AmB PITS UrSkAgCAgB AgC Re AgB W InC No AgC Wo EvC NoAmC Wo AgB AgB Ur Ng SkAmB ReOs AgCNo AgD No Ur No InC AgD EvC Tu AmB EvB AgD Pu InC EvCAmC NoEvC Ur EvB AkFBr Os AgD AmC AgB AgD AmB Os Os NoAmC Pk AkF No AmC EvC NoNo AgDBr AgBAgC AgBAmC Re Re KpBAmBNoPyPySkNgAgBEvC EvC Sk NoEvBNo Pu BrPuOsOsWo AmC Panther Lake Lake Youngs Lake Washington B l a ck Ri v er Gr e enR iverCeda rRiverDuwamish Wat erwa yUV167 UV900 UV515 UV169 UV900 UV167BN IncBN IncBBNNIInnccSSEE RReennttoonnIIss ss aa qq uuaahhRRdd S 2nd StS 2nd St RReennttoonnMMaapplleeVVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEEMMaaiinnAAvveeSSMMaarrttiinn LL KKiinnggJJrrWWaayySS SSWW SSuunnsseett BBllvvdd RRaaii nnii eerr AAvveeNNNE 3rd St NE 3rd St II--440055FFWWYYSW 43rd StSW 43rd St SSEE CC aarrrrRR dd NE 4th StNE 4th St SS GG rr aa dd yy WW aa yy SSEERReennttoonnMMaapplleeVVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNBBeennssoonnDDrrSSSSuunnsseettBBllvvddNN OOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNNEE DDuuvvaallllAAvveeNNEESR 167SR 167114400tthh WWaayySSEEWWaatteerrss AA vv ee SS NNEE2277tthh SStt HHoo uu sseerr WWaayyNN115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St PPuuggeettDDrrSSEERR eennttoonnAAvvee SS GGaarrddeennAAvveeNNSSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEEII nntt eerr uurr bbaannAAvveeSS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeettrroovviittsskkyyRRdd SSoouutthhcceenn ttee rr BB llvv dd EEVVaalllleeyyHHwwyySShhaattttuucckkAAvveeSSRRaaiinniieerrAAvvee SS TTaallbboottRRddSSRRee nnttoo nn AA vv ee SS116644tthhAAvveeSSEESE 208th StSE 208th St SSWWLLaannggssttoonnRRdd SE 72nd StSE 72nd St SE 128th StSE 128th St 112244tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS 118800tthh SStt CCooaallCCrr eeeekkPPkkwwyySSEESW 41st StSW 41st St N 30th StN 30th St T a y l o r P l NW T a y l o r P l NW114400tthhAAvveeSSEE112288tthhAAvveeSSEE111166tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BB eeaaccoonn AAvv ee SS FFoorreessttDDrrSSEE UUnniioonnAAvveeSSEESE 164th StSE 164th St NNiilleeAAvveeNNEE114488tthhAAvveeSSEESSEEMMaayyVVaalllleeyy RRdd SS EE 22 00 44 tthh WW aayySW 34th StSW 34th St SSEE JJoonneess RR dd SE 144th StSE 144th StEEMMeerrcceerrWWaayy 114488tthhAAvveeSSEEWWMM eerrcceerrWWaayy115544tthhPPllSSEEEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 Reference 1-C Renton City Limits Potential Annexation Area Groundwater Protection Area Boundary Aquifer Protection Area Zone 1 Aquifer Protection Area Zone 1 Modified Soil Type AgB AgC AgD AkF AmB AmC An BeC BeD Bh Br EvB EvC EvD EwC InA InC InD KpB KpC KpD Ma Ng Nk No Or Os OvC OvD PITS Pc Pk Pu Py RdC RdE Re Rh Sh Sk Sm So Tu Ur W Wo Date: 01/09/2014 012MilesμSoil Survey PROJECT SITE Core Design, Inc. TOWNS ON 12TH Page 4-9 Core Design, Inc. TOWNS ON 12TH Page 4-10 4.1.1 Existing Conditions See Existing/Upstream Conditions exhibit on the following pages. The existing basin boundary area, 6.70 acres, will include the property area, 6.55 acre, plus the proposed frontage improvement area along NE 12th Street, 0.15 acre. As part of the project, the City has requested that the existing sidewalk along NE Sunset Blvd be relocated to create a planter stip. Due to topographical limitations, the project is unable to collect runoff from this replaced impervious surface. However, per Section 1.2.3.2.E of the 2022 RSWDM, runoff from this target surface area is able to bypass the required onsite flow control facilities without providing compensatory mitigation. See Section 4.1.4 for detail on how this area meets the conditions allowing this. The following information was used for generating flow frequencies. EXISTING CONDITIONS Total Area = 6.70 acres GROUND COVER AREA (acres) Till-Forest 6.70 4.1.2 Upstream Conditions See Existing/Upstream Conditions exhibit on the following pages. The project site has two upstream areas. The first upstream area is located along the southern half of the west boundary line of the site. This upstream area is tributary to the existing wetland located on site. The second upstream area is located at the southwest corner of the site. This area is tributary to the site. Impervious coverage from all these areas were delineated through the use of aerial images at correct scales to outline the impervious areas. The following information was used for generating flow frequencies. UPSTREAM CONDITIONS Total Area = 1.19 acres GROUND COVER AREA (acres) Till-Grass 0.78 Driveway 0.15 Sidewalk 0.03 Roof 0.23 The below inputs into WWHM for the basin include both the existing area (6.70 acres) and the upstream areas draining to the site (1.19 acres). DESIGNE N G I N E E R I N G P L A N N I N G S U R V E Y I N G12100 NE 195th St, Suite 300Bothell, Washington 98011425.885.7877 Fax 425.885.796321008 Core Design, Inc. TOWNS ON 12TH Page 4-12 4.1.3 Developed Conditions See Developed/Upstream Conditions exhibit on the following pages. Some area swapping has been incorporated into the flow control and water quality treatment design. As part of the project site design, a portion of drainage from NE 12th Street, not part of the project basin outlined in the Existing Conditions Section, will be collected and treated. In return a portion of the constructed Right-of-Way of NE 12th Street will not be collected by the proposed system. The collected upstream areas exceed the area proposed to be released. See the table below for a summary of the collected and released areas. NE 12th Street Area Swap Released (sf) Collected (sf) Difference (sf) Difference (ac) Impervious (Road) 3,265 4,011 746 0.02 Pervious 1,366 3,854 2,488 0.05 Total Area 4,631 7,865 3,234 0.07 Impervious areas for the site were calculated based on the proposed site plan per the project’s designation as multi-family. The impervious areas are summarized in the table below. The site areas for the upstream condition are provided in Section 4.1.2 of this report. No credit for onsite BMPs is proposed to be taken. DEVELOPED CONDITIONS Total Area = 6.70 ac Sidewalk 0.52 Road 1.15 Driveway 0.32 Roof 1.76 Grass 2.95 The inputs into WWHM combine the developed basin area (6.70 acres), the additional area collected due to the area swap (0.07 acres), and the upstream areas draining to the site (1.19 acres). DESIGNE N G I N E E R I N G P L A N N I N G S U R V E Y I N G12100 NE 195th St, Suite 300Bothell, Washington 98011425.885.7877 Fax 425.885.796321008 Core Design, Inc. TOWNS ON 12TH Page 4-14 FLOW CONTROL FACILITY ANALYSIS Flow control facilities have been designed using WWHM. Proposed vault dimensions are given below along with WWHM generated modeling reports. The project will utilize a standard detention vault to provide flow control. The required surface area of the vault is 7,144 square feet. The project will provide a vault surface area of 7,158 square feet. Using the maximum water surface of the 50-year storm (Elev. 415.92) as calculated in the vault overflow analysis below under VAULT OVERFLOW ANALYSIS, along with the normal water surface elevation (Elev. 403.50), the minimum required volume will be the surface area times the live storage depth, 7,144 square feet x (415.92 – 403.50) = 88,729 cubic feet. The proposed detention vault will provide a volume of 88,902 cubic feet, exceeds the required volume, and therefore provides adequate flow control. The full WWHM generated report is provided in Appendix A. VAULT OVERFLOW ANALYSIS The water surface elevations within the vault are conservatively calculated based on the equation below as WWHM does not accurately calculate the water surface when the water surface starts to exceed the riser elevation. The primary overflow for the vault is the riser pipe on the control structure. The water surface elevation above the riser for the 100-year developed flow is calculated assuming all orifices are plugged. The 100- year, 15-minute return period storm for the developed tributary area is 5.87 cfs. See snip from WWHM model below which shows the developed site undetained flows. To pass the 100-year, 15-minute return period storm, 5.87 cfs, through a 24-inch overflow riser, 0.45 feet of head is required per the following equation: = 9.739 / 5.87 = 9.739 2 / The primary overflow elevation, elevation 415.95, would therefore, be equal to the elevation of the top of the riser, elevation 415.50, plus the amount of head required to pass the 100-year return period storm, 0.45 feet. This primary overflow elevation has been utilized as the vault’s tailwater elevation for sizing of the conveyance system. The 50-year maximum water surface for the vault is determined in the same way as the 100-year overflow. The water surface elevation above the riser for the 50-year developed flow is calculated assuming all orifices are plugged. The 50-year, 15-minute return period storm for the developed tributary area is 5.22 cfs. See snip from WWHM model below which shows the developed site undetained flows, also provided in the WWHM report in Appendix A under POC 2. To pass the 50-year, 15-minute return period storm, 5.22 cfs, through a 24-inch overflow riser, 0.42 feet of head is required per the following equation: = 9.739 / 5.22 = 9.739 3 / The 50-year maximum water surface elevation, elevation 415.92, would therefore, be equal to the elevation of the top of the riser, elevation 415.50, plus the amount of head required to pass the 50-year return period storm, 0.42 feet. Core Design, Inc. TOWNS ON 12TH Page 4-15 Core Design, Inc. TOWNS ON 12TH Page 4-16 ON-SITE BMPs Per Section 1.2.9.1 in the RSWDM, projects subject to Core Requirement #9 must apply flow control BMPs to either supplement the flow mitigation provided by required flow control facilities or provide flow mitigation where flow control facilities are not required. Flow control BMPs must be implemented per the requirements and approach detailed in Sections 1.2.9.2 and 1.2.9.3 for individual lots or subdivisions and road improvement projects, respectively. The Section applicable to this project is Section 1.2.9.3. Per Section 1.2.9.3, subdivision projects, flow control BMPs must be selected and applied according to the subdivision and road improvement projects BMP requirements. The category of requirements applicable to the subject project is the Small Subdivision Project BMP Requirements. As such, onsite plat infrastructure will meet the requirements described in Section 1.2.9.3.2 for Small Road Improvement and Urban Road Improvement Project BMP Requirements. The BMP Requirements under section 1.2.9.3.2 of the RSWDM are as follows: 1. The feasibility and applicability of full dispersion as detailed in Appendix C, Section C.2.1 must be evaluated for all target impervious surfaces. If feasible and applicable, full dispersion must be implemented as part of the proposed project. Typically, small lot full dispersion will be applicable only in subdivisions where enough forest was preserved by tract, easement, or covenant to meet the minimum requirements for full dispersion in Appendix C, Section C.2.1.1 Full Dispersion is not feasible due to being unable to meet the minimum required flow path with the appropriate slopes. 2. All target impervious surfaces not mitigated by Requirement 1 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list. Use of a given BMP is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Infeasible BMPs are not required to be implemented. The BMPs listed below may be located anywhere on the site/lot subject to the limitations and design specifications for each BMP. These BMPs must be implemented as part of the proposed project. • Full Infiltration per Appendix C, Section C.2.2, or per Section 5.2, whichever is applicable Full Infiltration is not feasible due to existing onsite non-infiltrating till soils. • Limited Infiltration per Appendix C, Section C.2.3, Limited infiltration is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. • Bioretention per Appendix C, Section C.2.6, sized as follows: o SeaTac regional scale factor equals 1.0: In till soils, provide bioretention volume based on 0.6 inches of equivalent storage depth; in outwash soils provide bioretention volume based on 0.1 inches of equivalent storage depth, Core Design, Inc. TOWNS ON 12TH Page 4-17 o SeaTac regional scale factor greater than 1.0: In till soils, provide bioretention volume based on 0.8 inches of equivalent storage depth; in outwash soils, provide bioretention volume based on 0.4 inches of equivalent storage depth, Bioretention is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. • Permeable Pavement per Appendix C, Section C.2.7 Permeable Pavement is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. 3. All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using the Basic Dispersion BMP described below. Use of Basic Dispersion is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Infeasible BMPs are not required to be implemented. Basic Dispersion BMPs may be located anywhere on the site/lot subject to the limitations and design specifications cited in Appendix C. The BMP must be implemented as part of the proposed project. • Basic Dispersion per Appendix C, Section C.2.4, Basic dispersion is not feasible due to being unable to meet the minimum required flow path with the appropriate slopes and the steep slope adjacent to the site. 4. The soil moisture holding capacity of new pervious surfaces (target pervious surfaces) must be protected in accordance with the soil amendment BMP as detailed in Appendix C, Section C.2.13. Soil amendment will be incorporated for disturbed areas not covered with hard surfaces. Additionally, BMPs for lot improvements have been analyzed to meet the requirements of Section 1.2.9.2 and Section 1.2.9.4.1. Per Section 1.2.9.2.1, if the proposed project is on a site/lot smaller than 22,000 square feet, then on-site BMPs must be applied as specified in the requirements below OR the project must demonstrate compliance with the LID Performance Standard using an approved continuous runoff model. Since the proposed lots under this project will all be less than 22,000 square feet, and the project has not elected to meet the LID Performance Standard, the on lot BMPs have been evaluated as follows: 1. The feasibility and applicability of full dispersion as detailed in Appendix C, Section C.2.1 must be evaluated for all target impervious surfaces. If feasible and applicable, full dispersion must be implemented as part of the proposed project. Typically, small lot full dispersion will be applicable only in subdivisions where enough forest was preserved by tract, easement, or covenant to meet the minimum requirements for full dispersion in Appendix C, Section C.2.1.1 Core Design, Inc. TOWNS ON 12TH Page 4-18 Full Dispersion is not feasible due to being unable to meet the minimum required flow path with the appropriate slopes. 2. Where full dispersion of target impervious roof areas is not feasible or applicable, or will cause flooding or erosion impacts, the feasibility and applicability of full infiltration as detailed in Appendix C, Section C.2.2 must be evaluated (note, this will require a soils report for the site/lot). If feasible and applicable, full infiltration of roof runoff must be implemented as part of the proposed project. Full Infiltration is not feasible due to existing onsite non-infiltrating till soils. 3. All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list. Use of a given BMP is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. The BMPs listed below may be located anywhere on the site/lot subject to the limitations and design specifications for each BMP. These BMPs must be implemented as part of the proposed project. • Full Infiltration per Appendix C, Section C.2.2, or per Section 5.2, whichever is applicable Full Infiltration is not feasible due to existing onsite non-infiltrating till soils. • Limited Infiltration per Appendix C, Section C.2.3, Limited infiltration is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. • Rain Gardens per Appendix C, Section C.2.12, sized as follows: o Rain gardens have a maximum contributing area of 5,000 square feet. o Rain gardens must have a minimum horizontal projected surface area below the overflow that is at least 5% of the area draining to it Rain Gardens are not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. • Bioretention per Appendix C, Section C.2.6, sized as follows: o SeaTac regional scale factor equals 1.0: In till soils, provide bioretention volume based on 0.6 inches of equivalent storage depth; in outwash soils provide bioretention volume based on 0.1 inches of equivalent storage depth, o SeaTac regional scale factor greater than 1.0: In till soils, provide bioretention volume based on 0.8 inches of equivalent storage depth; in outwash soils, provide bioretention volume based on 0.4 inches of equivalent storage depth, Core Design, Inc. TOWNS ON 12TH Page 4-19 Bioretention is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. • Permeable Pavement per Appendix C, Section C.2.7 Permeable Pavement is not feasible per the project’s geotechnical engineer. Per the Geotechnical Report prepared by Terra Associates, Inc, dated 8/5/21, soils observed on site are not suitable for Flow Control BMPs due to the presence of weathered glacial till at shallow depths. 4. All target impervious surfaces not mitigated by Requirements 1, 2 and 3 above, must be mitigated to the maximum extent feasible using the Basic Dispersion BMP described below. Use of Basic Dispersion is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. Basic Dispersion BMPs may be located anywhere on the site/lot subject to the limitations and design specifications cited in Appendix C. The BMP must be implemented as part of the proposed project. • Basic Dispersion per Appendix C, Section C.2.4, Basic dispersion is not feasible due to being unable to meet the minimum required flow path with the appropriate slopes and the steep slope adjacent to the site. 5. BMPs must be implemented, at minimum, for impervious area equal to at least 10% of the site/lot for site/lot sizes up to 11,000 square feet and at least 20% of the site/lot for site/lot sizes between 11,000 and 22,000 square feet. For projects located in Zone 1 of the Aquifer Protection Area, these impervious area amounts must be doubled. Doubling of the minimum impervious area required for BMP implementation in Zone 1 of the Aquifer protection Area is not required for projects located within 200 feet of a steep slope hazard area, landslide hazard, or erosion hazard area. If these minimum areas are not mitigated using feasible BMPs from Requirements 1, 2, 3, and 4 above, one or more BMPs from the following list are required to be implemented to achieve compliance. These BMPs must be implemented as part of the proposed project. • Reduced Impervious Surface Credit per Appendix C, Section C.2.9, • Native Growth Retention Credit per Appendix C, Section C.2.10. • Tree Retention Credit per Appendix C, Section C.2.14 The impervious area requiring mitigation is equal to 10% of each individual lot Area. These areas for each lot are summarized in the table at the end of this section. The total of the lot area for the 90 proposed lots is 129,586 square feet. The impervious area requiring mitigation is, therefore, equal to 10% of 129,586 square feet, or 12,959 square feet, as evaluated on a lot by lot basis. Reduced Impervious Surface Credit has been evaluated for the project site. This project cannot use wheel strip driveways due to the proposed parking layout, cannot implement a minimum disturbance foundation due to the building type. And open grid decking over pervious surface is not applicable. Additionally, the proposed improvements to the project create more than the threshold of 4,000 Core Design, Inc. TOWNS ON 12TH Page 4-20 square feet or 4% of the total site area (whichever is greater) in impervious surface. Therefore, minimum design requirement #1 cannot be met; hence this BMP cannot be claimed for the proposed site improvements. Since the proposed project will develop the entire site with the exception of sensitive areas and associated buffers, a Native Growth Retention Credit is not feasible. Tree Retention Credits are not applicable to the project site. 6. The soil moisture holding capacity of new pervious surfaces (target pervious surfaces) must be protected in accordance with the soil amendment BMP as detailed in Appendix C, Section C.2.13. Soil amendment will be incorporated for disturbed areas not covered with hard surfaces. 7. Any proposed connection of roof downspouts to the local drainage system must be via a perforated pipe connection as detailed in Appendix C, Section C.2.11. All proposed connections to the local drainage system will be provided via a perforated pipe connection. As such, BMPs have been applied to the plat infrastructure and individual lots to the maximum extent feasible and Core Requirement #9 is considered to have been met. Core Design, Inc. TOWNS ON 12TH Page 4-21 Lot #Area (sf) 10% Lot Lot #Area (sf) 10% Lot Lot #Area (sf) 10% Lot Lot #Area (sf) 10% Lot Area (sf) 1 4157 416 25 806 81 49 1320 132 73 1544 154 2 2397 240 26 806 81 50 978 98 74 1608 161 3 2476 248 27 1281 128 51 982 98 75 992 99 4 2464 246 28 1281 128 52 1405 141 76 2924 292 5 3009 301 29 806 81 53 1294 129 77 2969 297 6 1771 177 30 1571 157 54 978 98 78 682 68 7 2336 234 31 1603 160 55 978 98 79 683 68 8 2324 232 32 798 80 56 1320 132 80 1087 109 9 2355 236 33 798 80 57 1320 132 81 1106 111 10 2011 201 34 1268 127 58 979 98 82 737 74 11 798 80 35 1268 127 59 1789 179 83 1148 115 12 1268 127 36 798 80 60 2371 237 84 1197 120 13 1268 127 37 2011 201 61 1151 115 85 739 74 14 798 80 38 1666 167 62 1961 196 86 1152 115 15 798 80 39 1584 158 63 1883 188 87 1249 125 16 1603 160 40 1998 200 64 1236 124 88 910 91 17 1691 169 41 1121 112 65 1241 124 89 911 91 18 868 87 42 1512 151 66 1786 179 90 1132 113 19 1380 138 43 1453 145 67 1528 153 20 1380 138 44 914 91 68 1080 108 21 868 87 45 1643 164 69 1080 108 22 868 87 46 1656 166 70 2679 268 23 1654 165 47 978 98 71 1586 159 24 1400 140 48 1320 132 72 1003 100 4.1.4 NE Sunset Blvd Sidewalk Analysis As discussed in Section 4.1.1, the proposed sidewalk replacement to provide a planter strip between the back of curb and front of sidewalk will not be tributary to the proposed flow control facility. The table below includes areas used in this analysis of the sidewalk replacement. NE Sunset Blvd Sidewalk Replacement Existing – Actual (sf) Existing – Modeled (sf) Proposed (sf) Impervious 3,180 0 3,493 Pervious 3,732 6,912 3,419 Total Area 6,912 6,912 6,912 The resulting flow frequencies, as generated by WWHM using the Existing-Modeled and Proposed areas is included in the image below. The WWHM report is also included in Appendix A for reference. Per the flow frequencies, the 100 year flow rate for the sidewalk replacement (0.1144) results in an increase of 0.0844 cfs over the predeveloped 100-year flow rate (0.0296 cfs). Core Design, Inc. TOWNS ON 12TH Page 4-22 Per Section 1.2.3.2.E of the 2022 RSWDM, some project runoff subject to flow control may bypass required onsite flow control facilities provided that all of the following conditions are met: 1. The point of convergence for runoff discharged from the bypassed target surfaces and from the project’s flow control facility must be within a quarter mile downstream of the facility’s project site discharge point. Runoff from the bypassed target surfaces will intercept runoff discharge from the project’s flow control facility at the flow control facility’s discharge to the existing system within NE Sunset Blvd. Thus, this condition is met. 2. The increase in the existing site conditions 100-year peak discharge from the area of bypassed target surfaces must not exceed 0.4 cfs. As discussed at the beginning of this section, the increase in the existing site conditions 100-year peak discharge from the proposed sidewalk improvements to be bypassed is 0.0844 cfs, less than the maximum of 0.4 cfs. 3. Runoff from the bypassed target surfaces must not create a significant adverse impact to downstream drainage systems, salmonid habitat, or properties as determined by CED. Runoff from the bypassed target surfaces will be equivalent to the runoff from the existing sidewalk the proposed sidewalk is replacing. Therefore, the bypassed sidewalk will not create any additional impact to downstream systems from the existing condition, and this condition is considered to have been met. 4. Water quality requirements applicable to the bypassed target surfaces must be met. The bypassed target surface is a concrete sidewalk, not subject to vehicular access. As such, the target surfaces are non-pollution generating impervious surfaces and there is no water quality requirement. Therefore, this condition has been met. 5. Compensatory mitigation by a flow control facility must be provided so that the new effect at the point of convergence downstream is the same with or without the bypass. This mitigation may be waived if the existing site conditions 100-year peak discharge from the area of bypassed target surfaces is increased by no more than 0.15 cfs (modeled using 15-minute time steps) and on-site BMPs as detailed in Appendix C are applied to all impervious surfaces within the area of bypassed target surfaces. Core Design, Inc. TOWNS ON 12TH Page 4-23 As discussed at the beginning of this section, the increase in the existing site conditions 100-year peak discharge from the proposed sidewalk improvements to be bypassed is 0.0844 cfs, less than 0.15 cfs. Additionally, BMPs have been applied to all impervious surfaces proposed to the maximum extent feasible. Therefore, no mitigate by a flow control facility is required for the proposed sidewalk improvements. 4.2 Water Quality Treatment Analysis and Design Per Core Requirement #8: Water Quality, the project is required to provide a water quality system to treat stormwater runoff from pollution-generating surfaces. The site is located within an Enhanced Basic Water Quality Area and is therefore required to implement a system from the Enhanced Basic Water Quality Menu described in Section 6.1.2 of the RSWDM. The project proposes to implement a Biopod proprietary water quality media filter manufactured by Oldcastle as per Enhanced Basic Option 5 in the RSWDM. The Biopod filter has General Use Level Designation (GULD) Approval from the Department of Ecology. Water Quality calculations are shown below. The Biopod system is located downstream of the vault; therefore, per Section 6.2.1 of the 2022 RSWDM, the water quality design flow for sizing of the system is the full 2-year release rate from the detention facility, determined using the approved continuous runoff model. The resulting BioPod sizing is summarized in the table below. Sizing was confirmed with OldCastle for flow rate and mass loading capabilities. Biopod Sizing WWHM 2-year outflow from vault 0.270 cfs Selected BioPod BPU 816IB Treatment Rate of Selected BioPod 0.385 cfs ELEVATION VIEW 2X Ø36" BOLTED & GASKETED ACCESS COVERS. FIELD GROUT AS NEEDED TO MEET GRADE, BY OTHERS. COBBLES FOR ENERGY DISSIPATION Ø4" SLOTTED PVC UNDERDRAIN ACCESS CAP FOR OPTIONAL DRAIN-DOWN DEVICE BYPASS WEIR, EL: 403.87' OUTLET, Ø22" OPENING FOR Ø18" SD, FARSIDE. 4"x24" INLET WINDOW, IE: 403.37' 1'-5" 1'-8" TYP 3'-8 1/2" 8" TOP SLAB INLET, Ø22" OPENING FOR Ø18" SD, NEARSIDE. LEFT END VIEW 16'-0" 17'-4" PLAN VIEW 8'-0"9'-4" DIVIDER WALL 3'-10" 4" 3'-10" 2'-0"13'-6" MEDIA AREA6"8" TYPICAL WALL THICKNESS COBBLES FOR ENERGY DISSIPATION TOP SLAB NOT SHOWN IN THIS VIEW FOR CLARITY. COVERS SHOWN IN PHANTOM Ø4" SLOTTED PVC UNDERDRAIN 4"x24" INLET WINDOW, IE: 403.37' ACCESS CAP FOR OPTIONAL DRAIN-DOWN DEVICE OUTLET, Ø22" OPENING FOR Ø18" SD, IE: 401.20' BYPASS WEIR, EL: 403.87' INLET, Ø22" OPENING FOR Ø18" SD, IE: 403.50' A A-1463 TAMSA48CL35BTO M 0 8 AD EIE N 0T 1USA U D & & 7ED A U D & 9S 2 D R Y DRYL F UNOL F IN 1- LO 6 FUN 4 S A YR D D MA R8S9R WM A -85- A A-1463 TAMSA48CL35BTO M 0 8 AD EIE N 0T 1USA U D & & 7ED A U D & 9S 2 D R Y DRYL F UNOL F IN 1- LO 6 FUN 4 S A YR D D MA R8S9R WM A -85- MM/DD/YY MM/DD/YY 6" DRAIN ROCK 2" MULCH 4 1/4" ADJUST TO GRADE RIM: 414.50' 3'-10" DIVIDER WALL EL: 400.53' 13.97' [167.60"] 4'-0" 8" BASE SLAB 18" StormMix™ MEDIA 2X Ø36"x4" GRADE RINGS. 16X Ø36"x12" GRADE RINGS. 7 1/4" 2'-8" BYPASS WEIR OUTLET, Ø22" OPENING FOR Ø18" SD. 2X UNDERDRAIN OUTLET ORIFICE DIVIDER WALL 5.10' [61.20"] RIM: 406.30' ACCESS CAP FOR OPTIONAL DRAIN-DOWN DEVICE 6" ADJUST TO GRADE INLET, Ø22" OPENING FOR Ø18" SD. IE: 403.50' 2.80' [33.60"] 4"x24" INLET WINDOW, IE: 403.37' 2X Ø24" BOLTED & GADKETED ACCESS COVERS. FIELD GROUT AS NEEDED TO MEET GRADE, BY OTHERS. EL: 403.87' RIM: 406.30' IE: 401.20' 2X 1'-8" Bioretention/ BiofiltrationREVDESCRIPTIONBYDATE NOTES: 1.DESIGN LOADINGS: A.AASHTO HS-20-44 W/ IMPACT. B.DESIGN FILL: 9' MAXIMUM. C.ASSUMED WATER TABLE = 5' BELOW GRADE. D.DRY LATERAL EARTH PRESSURE (EFP) = 45 PCF. E.LATERAL LIVE LOAD SURCHARGE = 80 PSF (APPLIED TO 8' BELOW GRADE). F.NO LATERAL SURCHARGE FROM ADJACENT BUILDINGS, WALLS, PIERS, OR FOUNDATIONS. 2.CONCRETE 28 DAY COMPRESSIVE STRENGTH SHALL BE 5,000 PSI MINIMUM. 3.STEEL REINFORCEMENT: REBAR, ASTM A-615 OR A-706, GRADE 60. 4.MESH REINFORCEMENT: ASTM A-1064, S1.2, GRADE 80. 5.CEMENT: ASTM C-150 SPECIFICATION. 6.REFERENCE STANDARD: A.ASTM C 890 B.ASTM C 913 7.THIS STRUCTURE IS DESIGNED TO THE PARAMETERS NOTED HEREIN. PLEASE VERIFY THAT THESE PARAMETERS MEET PROJECT REQUIREMENTS (I.E. LIVE LOAD, FILL RANGE, WATER TABLE). IF DESIGN PARAMETERS ARE INCORRECT, REVIEWING ENGINEER/AUTHORITY SHALL NOTIFY OLDCASTLE INFRASTRUCTURE UPON REVIEW OF THIS SUBMITTAL. 8.OVERSIZED HOLES TO ACCOMMODATE SPECIFIC PIPE TYPE MUST BE CONCENTRIC TO PIPE ID. AFTER PIPES ARE INSTALLED, ALL ANNULAR SPACES SHALL BE FILLED WITH A MINIMUM OF 3000 PSI CONCRETE FOR FULL THICKNESS OF PRECAST WALLS. PIPES ARE TO BE FLUSH WITH THE INSIDE SURFACE OF THE CONCRETE STRUCTURE. 9.CONTRACTOR RESPONSIBLE TO VERIFY ALL SIZES, LOCATIONS AND ELEVATIONS OF OPENINGS. 10.CONTRACTOR RESPONSIBLE TO ENSURE ADEQUATE BEARING SURFACE IS PROVIDED (I.E. COMPACTED AND LEVEL PER PROJECT SPECIFICATIONS). 11.ADAPTORS/ANGLES AND EXTERNAL PIPING BY OTHERS. 12.MAXIMUM PICK WEIGHT: BASE = 37,900 LBS. (MEDIA SHIPPED SEPARATELY). INTERNAL DRAWING ID REVISION SHEET MFG DRAWN ENGINEER CHECKEDDATE SALES ORDER REV DATE - PRELIMINARY - NOT FOR CONSTRUCTION Core Design BioPod™ Biofilter System Underground Vault With Internal Bypass Ph: 800.579.8819 | www.oldcastleinfrastructure.com/stormwater THIS DOCUMENT IS THE PROPERTY OF OLDCASTLE INFRASTRUCTURE, INC.IT IS CONFIDENTIAL, SUBMITTED FOR REFERENCE PURPOSES ONLY AND SHALL NOT BE USED IN ANY WAY INJURIOUS TO THE INTERESTS OF, OR WITHOUT THE WRITTEN PERMISSION OF OLDCASTLE INFRASTRUCTURE, INC. COPYRIGHT © 2023 OLDCASTLE INFRASTRUCTURE, INC. ALL RIGHTS RESERVED. CUSTOMER JOB NAME 4/18/23 010-AU PPS AFD AFD - 2 4/26/2323-829371-BPU-816IB_BioPod Towns on 12th - Renton, WA 1 OF 1 Unit ID - BioPod BPU-816IB WADOE GULD Treatment Flow Capacity 172.8 gpm / 0.385 cfs Core Design, Inc. TOWNS ON 12TH Page 5-1 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN The conveyance system for the project site was designed for the 100-year, 24 hour storm event. Conveyance capacity was confirmed through the use of conveyance spreadsheets generated using the rational method to calculate flows for each area collected by each catch basin. The 100-year, 24-hour precipitation value for the project location was found to be 3.91 inches per Figure 3.2.1.D of the 2022 RSWDM. See the isopluvial map from the 2022 RSWDM provided in the following pages for reference. The flows generated from the conveyance spreadsheet were then input into a backwater analysis spreadsheet to confirm adequate conveyance sizing for the project. See the conveyance and backwater analysis spreadsheets included in the following pages. A Conveyance Exhibit, which designates the individual catch basin drainage basin boundaries assumed for the analysis, is also provided. WEIGHTED C VALUE A weighted C value for the project basin was used in the rational method spreadsheet. Impervious area has a C value of 0.9, and grass area has a C value of 0.25. These values, along with the developed basin areas, were used to calculate the weighted C value. See the calculation provided below. =3.0 ∗ 0.25 +3.7 ∗ 0.90 6.7 = 0.61 TAILWATER ELEVATION As discussed in Section 4 of this report under VAULT OVERFLOW ANALYSIS, the 100-year tailwater elevation is equal to the 100-year max water surface of the vault, which has been calculated to be 415.95. ANALYSIS RESULTS During the 100-year storm, all headwater elevations remained below the rim elevations of all catch basins. The conveyance system, therefore, is adequately sized to convey and contain up through the 100-year storm. 3.2.1 RATIONAL METHOD 2022 City of Renton Surface Water Design Manual 6/22/2022 3-17 FIGURE 3.2.1.D 100-YEAR 24-HOUR ISOPLUVIALS PROJECT SITE RATIONAL METHOD CONVEYANCE SYSTEM DESIGN LOCATION: KING COUNTY PR (24-HR RAINFALL):3.91 INCHES PROJECT NAME: Towns on 12th PROJECT NUMBER: 21008 PREPARED BY: KEL DESIGN STORM: 100 YEAR SUBBASIN PIPE PIPE PIPE ACTUAL TRAVEL PIPE CAPACITY SUMMARY LOCATION AREA SUM OF Tc IR QR MANNING'S SIZE SLOPE LENGTH VELOCITY (VR)TIME Q(FULL) V(FULL)QR/Q(FULL) FROM TO (AC) "C" (A * C) (A * C) (MIN) (IN/HR) (CFS) "n" (IN)(%) (FT) (FT/SEC) (MIN) (CFS) (FT/SEC) (%) 36 32 0.201 0.61 0.122 0.122 6.30 3.20 0.392 0.012 12 3.280 100 4.49 0.37 6.990 8.90 5.6% 35 31 0.487 0.61 0.297 0.297 6.30 3.20 0.951 0.012 12 6.140 60 7.37 0.14 9.564 12.18 9.9% 34 33 0.158 0.61 0.096 0.096 6.30 3.20 0.308 0.012 12 0.510 79 2.21 0.59 2.756 3.51 11.2% 33 32 0.162 0.61 0.099 0.195 6.89 3.02 0.590 0.012 12 0.510 97 2.72 0.59 2.756 3.51 21.4% 32 31 0.101 0.61 0.061 0.379 7.49 2.87 1.087 0.012 12 3.480 86 6.37 0.22 7.200 9.17 15.1% 31 37 0.099 0.61 0.060 0.736 7.71 2.82 2.074 0.012 12 1.200 45 5.33 0.14 4.228 5.38 49.1% 37 Vault 0.357 1.61 0.574 1.310 7.85 2.79 3.651 0.012 12 4.460 9 10.02 0.01 8.151 10.38 44.8% 30 11 0.273 0.61 0.166 0.166 6.30 3.20 0.532 0.012 12 0.500 152 2.62 0.96 2.729 3.47 19.5% 29 28 0.293 0.61 0.179 0.179 6.30 3.20 0.572 0.012 12 7.170 78 6.65 0.19 10.335 13.16 5.5% 28 27 0.323 0.61 0.197 0.375 6.49 3.14 1.179 0.012 12 11.730 25 9.93 0.04 13.219 16.83 8.9% 15 14 0.271 0.61 0.165 0.165 6.30 3.20 0.528 0.012 12 2.250 54 4.46 0.20 5.790 7.37 9.1% 13 14 0.244 0.61 0.149 0.149 6.30 3.20 0.477 0.012 12 0.500 19 2.52 0.12 2.729 3.47 17.5% 14 27 0.119 0.61 0.073 0.387 6.50 3.14 1.215 0.012 12 2.240 75 5.70 0.22 5.777 7.36 21.0% 27 11 0.055 0.61 0.034 0.796 6.72 3.07 2.447 0.012 12 11.550 25 12.61 0.03 13.117 16.70 18.7% 26 25 0.057 0.61 0.035 0.035 6.30 3.20 0.112 0.012 12 0.500 172 1.65 1.74 2.729 3.47 4.1% 25 24 0.033 0.61 0.020 0.055 8.04 2.75 0.152 0.012 12 3.320 180 3.40 0.88 7.033 8.95 2.2% 24 10 0.035 0.61 0.021 0.077 8.92 2.57 0.197 0.012 12 22.360 26 7.09 0.06 18.251 23.24 1.1% 23 22 0.323 0.61 0.197 0.197 6.30 3.20 0.630 0.012 12 4.450 24 5.86 0.07 8.142 10.37 7.7% 22 8 0.010 0.61 0.006 0.203 6.37 3.18 0.646 0.012 12 27.610 27 11.10 0.04 20.281 25.82 3.2% 21 20 0.101 0.61 0.062 0.062 6.30 3.20 0.198 0.012 12 0.500 42 1.96 0.35 2.729 3.47 7.3% 20 19 0.095 0.61 0.058 0.120 6.65 3.09 0.370 0.012 12 0.500 34 2.31 0.25 2.729 3.47 13.6% 19 8 0.097 0.61 0.059 0.179 6.90 3.02 0.540 0.012 12 2.830 82 4.88 0.28 6.493 8.27 8.3% 18 7 0.263 0.61 0.161 0.161 6.30 3.20 0.514 0.012 12 25.790 26 9.48 0.05 19.601 24.96 2.6% 17 16 0.211 0.61 0.129 0.129 6.30 3.20 0.412 0.012 12 0.500 119 2.42 0.82 2.729 3.47 15.1% RATIONAL METHOD CONVEYANCE SYSTEM DESIGN LOCATION: KING COUNTY PR (24-HR RAINFALL):3.91 INCHES PROJECT NAME: Towns on 12th PROJECT NUMBER: 21008 PREPARED BY: KEL DESIGN STORM: 100 YEAR SUBBASIN PIPE PIPE PIPE ACTUAL TRAVEL PIPE CAPACITY SUMMARY LOCATION AREA SUM OF Tc IR QR MANNING'S SIZE SLOPE LENGTH VELOCITY (VR)TIME Q(FULL) V(FULL)QR/Q(FULL) FROM TO (AC) "C" (A * C) (A * C) (MIN) (IN/HR) (CFS) "n" (IN)(%) (FT) (FT/SEC) (MIN) (CFS) (FT/SEC) (%) 16 5 0.127 0.61 0.078 0.206 7.12 2.96 0.611 0.012 12 1.750 66 4.10 0.27 5.106 6.50 12.0% 11 10 0.027 0.61 0.016 0.979 7.26 2.93 2.865 0.012 15 0.500 76 4.15 0.31 4.948 4.03 57.9% 10 8 0.052 0.61 0.031 1.087 8.98 2.56 2.783 0.012 15 0.510 67 4.15 0.27 4.998 4.07 55.7% 8 7 0.290 0.61 0.177 1.646 9.25 2.51 4.137 0.012 15 0.510 73 4.56 0.26 4.998 4.07 82.8% 7 6 0.138 0.61 0.084 1.891 9.51 2.47 4.669 0.012 15 0.510 61 4.64 0.22 4.998 4.07 93.4% 6 5 0.140 0.61 0.085 1.976 9.73 2.43 4.810 0.012 18 0.520 37 4.83 0.13 8.206 4.64 58.6% 5 4 0.025 0.61 0.015 2.197 9.86 2.41 5.304 0.012 18 0.520 66 4.95 0.22 8.206 4.64 64.6% 4 2 0.044 0.61 0.027 2.225 10.08 2.38 5.295 0.012 18 0.540 54 4.99 0.18 8.362 4.73 63.3% 2 1 0.037 0.61 0.022 2.247 10.26 2.35 5.289 0.012 18 0.500 40 4.85 0.14 8.047 4.55 65.7% 1 Vault 0.000 0.61 0.000 2.247 10.40 2.33 5.245 0.012 18 20.180 16 18.22 0.01 51.120 28.93 10.3% BACKWATER CALCULATIONS PROJECT NAME: Towns on 12th PREPARED BY: KEL PROJECT NUMBER: 21008 DESIGN STORM: 100 YEAR ENTRANCE ENTRANCE EXIT OUTLET INLET APPROACH BEND JUNCTION PIPE PIPE MANNING'S OUTLET INLET PIPE FULL VELOCITY TAILWATER FRICTION HGL HEAD HEAD CONTROL CONTROL VELOCITY HEAD HEAD HEADWATER RIM FROM TO Q LENGTH SIZE "n" ELEVATION ELEVATION AREA VELOCITY HEAD ELEVATION LOSS ELEVATION LOSS LOSS ELEVATION ELEVATION HEAD LOSS LOSS ELEVATION ELEVATION FREEBOARD CB CB (CFS) (FT) (IN) VALUE (FT) (FT) (SQ FT) (FT/SEC) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) Vault 1 5.24 16 18 0.012 413.56 416.75 1.77 2.97 0.14 415.95 0.03 418.25 0.07 0.14 418.46 418.25 0.14 0.11 0.00 418.43 423.83 5.40 1 2 5.29 40 18 0.012 416.75 416.95 1.77 2.99 0.14 418.43 0.09 418.51 0.07 0.14 418.72 418.45 0.14 0.02 0.00 418.61 425.16 6.55 2 4 5.30 54 18 0.012 416.95 417.24 1.77 3.00 0.14 418.61 0.12 418.74 0.07 0.14 418.95 418.74 0.14 0.03 0.00 418.84 426.10 7.26 4 5 5.30 66 18 0.012 417.24 417.58 1.77 3.00 0.14 418.84 0.14 419.08 0.07 0.14 419.29 419.08 0.12 0.01 0.01 419.19 427.52 8.33 5 6 4.81 37 18 0.012 417.58 417.77 1.77 2.72 0.12 419.19 0.07 419.27 0.06 0.12 419.44 419.27 0.23 0.01 0.00 419.23 428.23 9.00 6 7 4.67 61 15 0.012 418.02 418.33 1.23 3.80 0.23 419.23 0.27 419.58 0.11 0.23 419.92 419.58 0.18 0.00 0.02 419.77 429.59 9.82 7 8 4.14 73 15 0.012 418.33 418.70 1.23 3.37 0.18 419.77 0.25 420.02 0.09 0.18 420.28 419.95 0.08 0.00 0.03 420.23 430.17 9.94 8 10 2.78 67 15 0.012 418.70 419.04 1.23 2.27 0.08 420.23 0.10 420.34 0.04 0.08 420.46 420.29 0.08 0.00 0.00 420.38 429.33 8.95 10 11 2.86 76 15 0.012 419.04 419.42 1.23 2.33 0.08 420.38 0.13 420.67 0.04 0.08 420.80 420.67 0.15 0.11 0.01 420.77 428.32 7.55 5 16 0.61 66 12 0.012 418.08 419.23 0.79 0.78 0.01 419.19 0.02 420.23 0.00 0.01 420.24 420.23 0.00 0.00 0.00 420.24 426.36 6.12 16 17 0.41 119 12 0.012 419.23 419.83 0.79 0.52 0.00 420.24 0.01 420.83 0.00 0.00 420.84 420.83 0.00 0.00 0.00 420.84 423.96 3.12 7 18 0.51 26 12 0.012 418.58 425.13 0.79 0.65 0.01 419.77 0.00 426.13 0.00 0.01 426.14 426.13 0.00 0.00 0.00 426.14 429.23 3.09 8 19 0.54 82 12 0.012 418.95 421.28 0.79 0.69 0.01 420.23 0.02 422.28 0.00 0.01 422.29 422.28 0.00 0.00 0.00 422.29 427.66 5.37 19 20 0.37 34 12 0.012 421.28 421.45 0.79 0.47 0.00 422.29 0.00 422.45 0.00 0.00 422.46 422.45 0.00 0.00 0.00 422.45 426.30 3.85 20 21 0.20 42 12 0.012 421.45 421.66 0.79 0.25 0.00 422.45 0.00 422.66 0.00 0.00 422.66 422.66 0.00 0.00 0.00 422.66 424.64 1.98 8 22 0.65 27 12 0.012 418.95 426.10 0.79 0.82 0.01 420.23 0.01 427.10 0.01 0.01 427.12 427.10 0.01 0.00 0.00 427.11 430.11 3.00 22 23 0.63 24 12 0.012 426.10 427.18 0.79 0.80 0.01 427.11 0.01 428.18 0.01 0.01 428.20 428.18 0.00 0.00 0.00 428.20 430.71 2.51 10 24 0.20 26 12 0.012 419.29 424.97 0.79 0.25 0.00 420.38 0.00 425.97 0.00 0.00 425.97 425.97 0.00 0.00 0.00 425.97 429.47 3.50 24 25 0.15 180 12 0.012 424.97 430.93 0.79 0.19 0.00 425.97 0.00 431.93 0.00 0.00 431.93 431.93 0.00 0.00 0.00 431.93 435.94 4.01 25 26 0.11 172 12 0.012 430.93 431.79 0.79 0.14 0.00 431.93 0.00 432.79 0.00 0.00 432.79 432.79 0.00 0.00 0.00 432.79 434.72 1.93 11 27 2.45 25 12 0.012 419.67 422.50 0.79 3.12 0.15 420.77 0.10 423.50 0.08 0.15 423.73 423.50 0.04 0.20 0.08 423.97 428.53 4.56 27 14 1.21 75 12 0.012 422.50 424.19 0.79 1.55 0.04 423.97 0.07 425.19 0.02 0.04 425.25 425.19 0.01 0.01 0.02 425.27 427.69 2.42 14 13 0.48 19 12 0.012 424.19 424.28 0.79 0.61 0.01 425.27 0.00 425.28 0.00 0.01 425.29 425.28 0.00 0.00 0.00 425.29 427.69 2.40 14 15 0.53 54 12 0.012 424.19 425.40 0.79 0.67 0.01 425.27 0.01 426.40 0.00 0.01 426.41 426.40 0.00 0.00 0.00 426.41 429.40 2.99 27 28 1.18 25 12 0.012 422.50 425.45 0.79 1.50 0.04 423.97 0.02 426.45 0.02 0.04 426.50 426.45 0.01 0.00 0.00 426.49 429.93 3.44 28 29 0.57 78 12 0.012 425.45 431.00 0.79 0.73 0.01 426.49 0.02 432.00 0.00 0.01 432.01 432.00 0.00 0.00 0.00 432.01 435.27 3.26 11 30 0.53 152 12 0.012 419.67 420.43 0.79 0.68 0.01 420.77 0.03 421.43 0.00 0.01 421.44 421.43 0.00 0.00 0.00 421.44 423.93 2.49 PIPE SEGMENT BACKWATER CALCULATIONS PROJECT NAME: Towns on 12th PREPARED BY: KEL PROJECT NUMBER: 21008 DESIGN STORM: 100 YEAR ENTRANCE ENTRANCE EXIT OUTLET INLET APPROACH BEND JUNCTION PIPE PIPE MANNING'S OUTLET INLET PIPE FULL VELOCITY TAILWATER FRICTION HGL HEAD HEAD CONTROL CONTROL VELOCITY HEAD HEAD HEADWATER RIM FROM TO Q LENGTH SIZE "n" ELEVATION ELEVATION AREA VELOCITY HEAD ELEVATION LOSS ELEVATION LOSS LOSS ELEVATION ELEVATION HEAD LOSS LOSS ELEVATION ELEVATION FREEBOARD CB CB (CFS) (FT) (IN) VALUE (FT) (FT) (SQ FT) (FT/SEC) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) (FT) PIPE SEGMENT Vault 37 3.65 9 12 0.012 414.06 414.46 0.79 4.65 0.34 415.84 0.08 415.92 0.17 0.34 416.42 415.97 0.11 0.20 0.00 416.52 421.20 4.68 37 31 2.07 45 12 0.012 414.46 415.00 0.79 2.64 0.11 416.52 0.13 416.65 0.05 0.11 416.81 416.00 0.03 0.06 0.05 416.89 422.18 5.29 31 32 1.09 86 12 0.012 415.00 417.97 0.79 1.38 0.03 416.89 0.07 418.97 0.01 0.03 419.01 418.97 0.01 0.04 0.01 419.06 427.11 8.05 32 33 0.59 97 12 0.012 417.97 418.46 0.79 0.75 0.01 419.06 0.02 419.46 0.00 0.01 419.47 419.46 0.00 0.00 0.00 419.47 424.71 5.24 33 34 0.31 79 12 0.012 418.46 418.86 0.79 0.39 0.00 419.47 0.00 419.86 0.00 0.00 419.86 419.86 0.00 0.00 0.00 419.86 422.05 2.19 31 35 0.95 60 12 0.012 415.00 418.70 0.79 1.21 0.02 416.89 0.04 419.70 0.01 0.02 419.73 419.70 0.00 0.00 0.00 419.73 422.70 2.97 32 36 0.39 100 12 0.012 417.97 421.26 0.79 0.50 0.00 419.06 0.01 422.26 0.00 0.00 422.27 422.26 0.00 0.00 0.00 422.27 425.26 2.99 DESIGNE N G I N E E R I N G P L A N N I N G S U R V E Y I N G12100 NE 195th St, Suite 300Bothell, Washington 98011425.885.7877 Fax 425.885.796321008 Core Design, Inc. TOWNS ON 12TH Page 6-1 6. SPECIAL REPORTS AND STUDIES The following reports and assessments are provided for reference and informational purposes only. Core Design takes no responsibility or liability for these reports, assessments, or designs as they were not completed under the direct supervision of Core Design. • Geotechnical Report by Terra Associates, Inc, dated 8/5/21 Core Design, Inc. TOWNS ON 12TH Page 7-1 7. OTHER PERMITS Additional permits related to this project include the following: · NPDES Permit Core Design, Inc. TOWNS ON 12TH Page 8-1 8. ESC ANALYSIS AND DESIGN Design of the Erosion and Sediment Control plan was completed in conformance with Core Requirement #5 per the 2022 RSWDM. Compliance with the 13 minimum requirements is demonstrated in the Construction Stormwater Pollution Prevention Plan report provided under separate cover. The site will follow Appendix D of the RSWDM for the erosion and sedimentation control design to reduce the discharge of sediment laden runoff from the site. Clearing limits will be established prior to any earthwork on the project site. Perimeter protection will be provided by silt fencing along the downstream perimeter of the disturbed areas to limit the downstream transport of sediment to streams, wetlands, and neighboring properties. Dust control, if required, will be provided by a water truck. A Certified Erosion and Sediment Control Lead inspector will be present onsite during all earthwork activities. The inspector shall determine frequency of watering of the project site and will authorize and direct any additional erosion and sediment control measures as needed during construction activities. The erosion control plan will be comprised of temporary measures, such as stabilized construction entrance, silt fence, temporary sediment trap, etc. Runoff from the site will sheet flow across cleared areas into temporary interceptor swales and into the temporary sediment pond. TESC POND SURFACE AREA CALCULATION The TESC pond minimum surface area (SA) is determined by the following equation; = 2080 ∗ , ! "#$ Where: = the minimum TESC pond surface area (sf) , ! "#$ = the 10-year, 15-minute peak flow = 3.9174 cfs , ! "#$ represents the unmitigated flow, as calculated by WWHM. The flow frequency output for the unmitigated model is provided below for reference, and the WWHM report is provided in Appendix A. Using this flow rate, the minimum TESC pond surface area was calculated to be: %&’()= *,+*, -. Figure 8-1 Undetained Developed Flow Core Design, Inc. TOWNS ON 12TH Page 8-2 Primary Spillway The required diameter for the principal spillway (riser pipe) for the pond has been determined based on the minimum diameter necessary to pass the peak volumetric flow rate using a 15-minute time step from the 10-year storm. This has been evaluated based on Figure 5.1.4.H: Riser Inflow Curves of the 2022 RSWDM. Based on the 15-minute, 10-year storm of 3.9174 cfs, the required diameter for the pond’s riser pipe, assuming one foot of freeboard, was found to be 15 inches. Emergency Overflow Spillway The emergency overflow spillway for the pond has been sized for the developed condition 100-year 10- minute peak flow 5.996 cfs. Per Section 5.1.1.2 of the 2022 RSWDM, the broad-crested weir equation, assuming a discharge coefficient of 0.6 and tangent of the angle of the side slopes of 3, has been used to size the spillway as follows: / =03.21 /1 − 2.4 Where = peak flow for the 100-year runoff event (cfs) / = length of weir (ft) – minimum 6 feet = height of water over weir (ft) – minimum 0.2 feet Assuming 0.5 feet for the height of water over the weir, the length of the weir was calculated to be 4.1 feet, so a spillway length of 6 feet will be provided for the pond. Dewatering Orifice The diameter of the dewatering orifice of the sediment pond was calculated using the following equations: #= 4.81 1045 6√ℎ Where # = orifice area (square feet) 6 = pond surface area (square feet) = 8,184 sf ℎ = head of water above the orifice (heigh of riser in feet) = 3.5 feet = 13.54 ∗9 # Where = the required diameter (inches) of the orifice Based on these equations, the orifice area was found to be 0.07 square feet which equates to an orifice diameter of 3.6 inches. For constructability, a 3-5/8-inch diameter dewatering orifice will be proposed. Core Design, Inc. TOWNS ON 12TH Page 9-1 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 9.1 Bond Quantities The City of Renton Bond Quantity Worksheet has been submitted under separate cover. 9.2 Facility Summaries A Facility Summary Sheet and Sketch has been included in the following pages. 9.3 Declaration of Covenant A Declaration of Covenant is not applicable at this time. TOWNS ON 12THRENTON, WALAKE WASHINGTON CEDAR RIVER1MATCHING FORESTEDOLDCASTLEBIOPOD1PARCEL #042305-9063, #042305-9099,#042305-9067, #042305-9140, #042305-9100,#042305-9101 and #032405-9247 TOWNS ON 12THRENTON, WADETENTION VAULTNORTH PORTION OF SITE3.7510090NORTH EAST CORNER OF VAULT31.968751.6251.781251PROPRIETARY MEDIA FILTER0.270 © 2023 Microsoft Corporation © 2023 Maxar ©CNES (2023) Distribution Airbus DS ROW 4ROAD AROW 6ROW 3 TRACT C2ROW 1ROW 2 ROW 4 ROW 5 NE SUNSET BLVD NE 12TH STREET ATTACHMENT 1 LEGEND STRUCTURE PIPE VAULT FACILITY SKETCH SHEET PROJECT NO. 21008 PROJECT: TOWNS ON 12TH LOCATION: ROAD A AND TRACT J PARCEL NO.: ADDRESS: DRAWN BY: KEL DATE: 4/27/2023 SHEET 1 OF 2 © 2023 Microsoft Corporation © 2023 Maxar ©CNES (2023) Distribution Airbus DS ROW 4ROAD AROW 6ROW 3 TRACT C2ROW 1ROW 2 ROW 4 ROW 5 NE SUNSET BLVD NE 12TH STREET FACILITY SKETCH SHEET ATTACHMENT 2 LEGEND MOW AREA VAULT NOTE: MOW AREA MAINTENANCE IS RESPONSIBILITY OF HOA 6,881 SF PROJECT NO. 21008 PROJECT: TOWNS ON 12TH LOCATION: ROAD A AND TRACT J PARCEL NO.: ADDRESS: DRAWN BY: KEL DATE: 4/27/2023 SHEET 2 OF 2 Core Design, Inc. TOWNS ON 12TH Page 10-1 10. OPERATIONS AND MAINTENANCE Operations and maintenance information for applicable facilities is included in the following pages. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-6 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non- floatables). No trash or debris in vault. Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipes Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-7 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole (cont.) Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can be opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damaged FROP-T T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-9 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED FROP-T Section (cont.) Damaged FROP-T (cont.) Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing cleanout gate Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing orifice plate Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions to orifice plate Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions to overflow pipe Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip of overflow pipe Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If applicable) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. Damaged or missing grate Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-10 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-11 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipe (cont.) Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. Damaged or missing grate Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-12 NO. 6 – CONVEYANCE PIPES AND DITCHES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/root growth in pipe Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged pipes Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive vegetation growth Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-17 NO. 11 – GROUNDS (LANDSCAPING) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard tree identified Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged tree or shrub identified Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-31 NO. 21 – PROPRIETARY FACILITY CARTRIDGE FILTER SYSTEMS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED In addition to the specific maintenance criteria provided below, all manufacturers’ requirements shall be followed. Facility Documentation Update facility inspection record after each inspection. Maintenance records are up to date. Provide certification of replaced filter media. Filter media is certified to meet manufacturer specifications. Site Trash and debris Any trash or debris which impairs the function of the facility. Trash and debris removed from facility. Contaminants and pollution Any evidence of contaminants or pollution such as oils, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Life cycle Once per year. Facility is re-inspected and any needed maintenance performed. Vault Treatment Area Sediment on vault floor Varies – Refer to manufacturer’s requirements. Vault is free of sediment. Sediment on top of cartridges Varies – Refer to manufacturer’s requirements. Vault is free of sediment. Multiple scum lines above top of cartridges Thick or multiple scum lines above top of cartridges. Probably due to plugged canisters or underdrain manifold. Cause of plugging corrected, canisters replaced if necessary. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch and any evidence of soil particles entering the structure through the cracks, or qualified inspection personnel determines the vault is not structurally sound. Vault replaced or repaired to design specifications. Baffles damaged Baffles corroding, cracking warping, and/or showing signs of failure as determined by maintenance/inspection person. Repair or replace baffles to specification. Filter Media Standing water in vault Varies – Refer to manufacturer’s requirements. No standing water in vault 24 hours after a rain event. Short circuiting Flows do not properly enter filter cartridges. Flows go through filter media. Underdrains and Clean-Outs Sediment and debris Underdrains or clean-outs partially plugged or filled with sediment and/or debris. Underdrains and clean-outs free of sediment and debris. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-32 NO. 21 – PROPRIETARY FACILITY CARTRIDGE FILTER SYSTEMS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large Access Doors/Plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can be opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat and cover access opening completely. Lifting Rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-40 NO. 28 – NATIVE VEGETATED SURFACE/NATIVE VEGETATED LANDSCAPE BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the native vegetated surface/native vegetated landscape site. Native vegetated surface site free of any trash or debris. Vegetation Insufficient vegetation Less than two species each of native trees, shrubs, and groundcover occur in the design area. A minimum of two species each of native trees, shrubs, and groundcover is established and healthy. Poor vegetation coverage Less than 90% if the required vegetated area has healthy growth. A minimum of 90% of the required vegetated area has healthy growth. Undesirable vegetation present Weeds, blackberry, and other undesirable plants are invading more than 10% of vegetated area. Less than 10% undesirable vegetation occurs in the required native vegetated surface area. Vegetated Area Soil compaction Soil in the native vegetation area compacted. Less than 8% of native vegetation area is compacted. Insufficient vegetation Less than 3.5 square feet of native vegetation area for every 1 square foot of impervious surface. A minimum of 3.5 square feet of native vegetation area for every 1 square foot of impervious surface. Excess slope Slope of native vegetation area greater than 15%. Slope of native growth area does not exceed 15%. NO. 29 – PERFORATED PIPE CONNECTIONS BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow into perforated pipe system or outfall of BMP is plugged or otherwise nonfunctioning. Outfall of BMP is receiving designed flows from perforated pipe connection. Inflow Inflow impeded Inflow into the perforated pipe is partially or fully blocked or altered to prevent flow from getting into the pipe. Inflow to the perforated pipe is unimpeded. Pipe Trench Area Surface compacted Ground surface over the perforated pipe trench is compacted or covered with impermeable material. Ground surface over the perforated pipe is not compacted and free of any impervious cover. Outflow Outflow impeded Outflow from the perforated pipe into the public drainage system is blocked. Outflow to the public drainage system is unimpeded. Outfall Area Erosion or landslides Existence of the perforated pipe is causing or exasperating erosion or landslides. Perforated pipe system is sealed off and an alternative BMP is implemented. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-47 NO. 38 – SOIL AMENDMENT BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Soil Media Unhealthy vegetation Vegetation not fully covering ground surface or vegetation health is poor. Yellowing: possible Nitrogen (N) deficiency. Poor growth: possible Phosphorous (P) deficiency. Poor flowering, spotting or curled leaves, or weak roots or stems: possible Potassium (K) deficiency. Plants are healthy and appropriate for site conditions Inadequate soil nutrients and structure In the fall, return leaf fall and shredded woody materials from the landscape to the site when possible Soil providing plant nutrients and structure Excessive vegetation growth Grass becomes excessively tall (greater than 10 inches); nuisance weeds and other vegetation start to take over. Healthy turf- “grasscycle” (mulch-mow or leave the clippings) to build turf health Weeds Preventive maintenance Avoid use of pesticides (bug and weed killers), like “weed & feed,” which damage the soil Fertilizer needed Where fertilization is needed (mainly turf and annual flower beds), a moderate fertilization program should be used which relies on compost, natural fertilizers or slow-release synthetic balanced fertilizers Integrated Pest Management (IPM) protocols for fertilization followed Bare spots Bare spots on soil No bare spots, area covered with vegetation or mulch mixed into the underlying soil. Compaction Poor infiltration due to soil compaction  To remediate compaction, aerate soil, till to at least 8-inch depth, or further amend soil with compost and re-till  If areas are turf, aerate compacted areas and top dress them with 1/4 to 1/2 inch of compost to renovate them  If drainage is still slow, consider investigating alternative causes (e.g., high wet season groundwater levels, low permeability soils)  Also consider site use and protection from compacting activities No soil compaction Poor infiltration Soils become waterlogged, do not appear to be infiltrating. Facility infiltrating properly Erosion/Scouring Erosion Areas of potential erosion are visible Causes of erosion (e.g., concentrate flow entering area, channelization of runoff) identified and damaged area stabilized (regrade, rock, vegetation, erosion control matting).For deep channels or cuts (over 3 inches in ponding depth), temporary erosion control measures in place until permanent repairs can be made Grass/Vegetation Unhealthy vegetation Less than 75% of planted vegetation is healthy with a generally good appearance. Healthy vegetation. Unhealthy plants removed/replaced. Appropriate vegetation planted in terms of exposure, soil and soil moisture. Noxious Weeds Noxious weeds Listed noxious vegetation is present (refer to current County noxious weed list). No noxious weeds present. BIOPOD SYSTEM™ Inspection & Maintenance Guide with StormMix Media™ DESCRIPTION The BioPod™ Biofilter System (BioPod) is a storm water biofiltration treatment system used to remove pollutants from storm water runoff. Impervious surfaces and other urban and suburban landscapes generate a variety of contaminants that can enter storm water and pollute downstream receiving waters unless treatment is provided. The BioPod system uses proprietary StormMix™ biofiltration media to capture and retain pollutants including total suspended solids (TSS), metals, nutrients, gross solids, trash and debris as well as petroleum hydrocarbons. FUNCTION The BioPod system uses engineered, high-flow rate filter media to remove storm water pollutants, allowing for a smaller footprint than conventional bioretention systems. Contained within a compact precast concrete vault, the BioPod system consists of a biofiltration chamber and an optional integrated high-flow bypass. The biofiltration chamber is filled with horizontal layers of aggregate, biofiltration media and mulch. Storm water passes vertically down through the mulch and biofiltration media for treatment. The mulch provides pretreatment by retaining most of the solids or sediment. The biofiltration media provides further treatment by retaining finer sediment and dissolved pollutants. The aggregate allows the media bed to drain evenly for discharge through an underdrain pipe or by infiltration. INSPECTION & MAINTENANCE OVERVIEW State and local regulations require all storm water management systems to be inspected on a regular basis and maintained as necessary to ensure performance and protect downstream receiving waters. Without maintenance, excessive pollutant buildup can limit system performance by reducing the operating capacity of the system and increasing the potential for scouring of pollutants during periods of high flow. Some configurations of the BioPod may require periodic irrigation to establish and maintain vegetation. Vegetation will typically become established about two years after planting. Irrigation requirements are ultimately dependent on climate, rainfall and the type of vegetation selected. INSPECTION & MAINTENANCE FREQUENCY Periodic inspection is essential for consistent system performance and is easily completed. Inspection is typically conducted a minimum of twice per year, but since pollutant transport and deposition varies from site to site, a site- specific maintenance frequency should be established during the first two or three years of operation. BIOPOD™ BIOFILTER WITH STORMMIX™ BIOFILTRATION MEDIA INSPECTION EQUIPMENT The following equipment is helpful when conducting BioPod inspections: | Recording device (pen and paper form, voice recorder, iPad, etc.) | Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) | PPE as required for entry | Traffic control equipment (cones, barricades, signage, flagging, etc.) | Manhole hook or pry bar | Flashlight | Tape measure | Socket INSPECTION PROCEDURES BioPod inspections are visual and are conducted without entering the unit. To complete an inspection, safety measures including traffic control should be deployed before the access covers or tree grates are removed. Once the covers have been removed, the following items should be checked and recorded (see form provided on page 6) to determine whether maintenance is required: | If the BioPod unit is equipped with an internal bypass, inspect the inlet rack (or inlet chamber on underground units) and outlet chamber and note whether there are any broken or missing parts. In the unlikely event that internal parts are broken or missing, contact Oldcastle Storm water at (800) 579-8819 to determine appropriate corrective action. | Note whether the curb inlet, inlet pipe, or inlet rack is blocked or obstructed. | If the unit is equipped with an internal bypass, observe, quantify and record the accumulation of trash and debris in the inlet rack or inlet chamber. The significance of accumulated trash and debris is a matter of judgment. Often, much of the trash and debris may be removed manually at the time of inspection if a separate maintenance visit is not yet warranted. | If it has not rained within the past 24 hours, note whether standing water is observed in the biofiltration chamber. | Finally, observe, quantify and record presence of invasive vegetation and the amount of trash and debris and sediment load in the biofiltration chamber. Erosion of the mulch and biofiltration media bed should also be recorded. Often, much of the invasive vegetation and trash and debris may be removed manually at the time of inspection if a separate maintenance visit is not yet warranted. Sediment load may be rated light, medium or heavy depending on the conditions. Loading characteristics may be determined as follows: • Light sediment load – sediment is difficult to distinguish among the mulch fibers at the top of the mulch layer; the mulch appears almost new. • Medium sediment load – sediment accumulation is apparent and may be concentrated in some areas; probing the mulch layer reveals lighter sediment loads under the top 1” of mulch. • Heavy sediment load – sediment is readily apparent across the entire top of the mulch layer; individual mulch fibers are difficult to distinguish; probing the mulch layer reveals heavy sediment load under the top 1” of mulch. www.oldcastleinfrastructure.com | (800) 735-5566 MAINTENANCE INDICATORS Maintenance should be scheduled if any of the following conditions are identified during inspection: | The concrete structure is damaged or the tree grate or access cover is damaged or missing | The inlet obstructed | Standing water is observed in the biofiltration chamber more than 24 hours after a rainfall event (use discretion if the BioPod is located downstream of a storage system that attenuates flow) | Trash and debris in the inlet rack cannot be easily removed at the time of inspection | Trash and debris, invasive vegetation or sediment load in the biofiltration chamber is heavy or excessive erosion has occurred MAINTENANCE EQUIPMENT The following equipment is helpful when conducting BioPod maintenance: MAINTENANCE PROCEDURES Maintenance should be conducted during dry weather when no flows are entering the system. In most cases, maintenance may be conducted without entering. Entry may be required to maintain BioPod Underground units, depending on system depth. Once safety measures such as traffic control are deployed, the access covers may be removed and the following activities may be conducted to complete maintenance: | Remove all trash and debris from the curb inlet and inlet rack manually or by using a vacuum truck as required. | Remove all trash and debris and invasive vegetation from the biofiltration chamber manually or by using a vacuum truck as required. | If the sediment load is medium or light but erosion of the biofiltration media bed is evident, redistribute the mulch with a rake or replace missing mulch as appropriate. If erosion persists, rocks may be placed in the eroded area to help dissipate energy and prevent recurring erosion. | If the sediment load is heavy, remove the mulch layer using a hoe, rake, shovel and bucket, or by using a vacuum truck as required. If the sediment load is particularly heavy, inspect the surface of the biofiltration media once the mulch has been removed. If the media appears clogged with sediment, remove and replace one or two inches of biofiltration media prior to replacing the mulch* layer. | Prune vegetation as appropriate and replace damaged or dead plants as required. | Replace the tree grate and/or access covers and sweep the area around the BioPod to leave the site clean. | All material removed from the BioPod during maintenance must be disposed of in accordance with local environmental regulations. In most cases, the material may be handled in the same manner as disposal of material removed from sumped catch basins or manholes. | Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) | PPE as required for entry | Traffic control equipment (cones, barricades, signage, flagging, etc.) | Manhole hook or pry bar | Flashlight | Tape measure | Rake, hoe, shovel and broom | Bucket | Pruners | Vacuum truck (optional) | Socket BIOPOD SURFACE www.oldcastleinfrastructure.com | (800) 735-5566 * Natural, shredded hardwood mulch should be used in the BioPod. Timely replacement of the mulch layer according to the maintenance indicators described above should protect the biofiltration media below the mulch layer from clogging due to sediment accumulation. However, whenever the mulch is replaced, the BioPod should be visited 24 hours after the next major storm event to ensure that there is no standing water in the biofiltration chamber. Standing water indicates that the biofiltration media below the mulch layer is clogged and must be replaced. Please contact Oldcastle Infrastructure at (800) 579-8819 to purchase the proprietary StormMix™ biofiltration media. | Rake, hoe, shovel and broom | Bucket | Pruners | Vacuum truck (optional) | Socket BIOPOD TREE BIOPOD PLANTER BIOPOD UNDERGROUND BIOPOD INSPECTION & MAINTENANCE LOG BioPod Model Inspection Date Location GOOD YES YES YES YES YES LIGHT YES YES - Schedule Maintenance DAMAGED NO NO NO NO NO MEDIUM NO NO - Schedule Re-Inspection MISSING HEAVY Condition of Internal Components Curb Inlet or Inlet Rack Blocked Standing Water in Biofiltration Chamber Trash and Debris in Inlet Rack Trash and Debris in Biofiltration Chamber Invasive Vegetation in Biofiltration Chamber Sediment in Biofiltration Chamber Erosion in Biofiltration Chamber Maintenance Requirements NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: www.oldcastleinfrastructure.com | (800) 735-5566 NOTES Core Design, Inc. TOWNS ON 12TH Page 10-3 Appendix A WWHM Report WWHM2012 PROJECT REPORT Vault 9/5/2023 10:44:41 AM Page 2 General Model Information WWHM2012 Project Name:Vault Site Name: Site Address: City: Report Date:9/5/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.167 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Vault 9/5/2023 10:44:41 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 6.7 C, Lawn, Mod 0.78 Pervious Total 7.48 Impervious Land Use acre ROOF TOPS FLAT 0.23 ROADS FLAT 0.15 SIDEWALKS FLAT 0.03 Impervious Total 0.41 Basin Total 7.89 Vault 9/5/2023 10:44:41 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 3.78 Pervious Total 3.78 Impervious Land Use acre ROADS MOD 1.17 ROOF TOPS FLAT 1.99 ROADS FLAT 0.47 SIDEWALKS FLAT 0.55 Impervious Total 4.18 Basin Total 7.96 Vault 9/5/2023 10:44:41 AM Page 5 Routing Elements Predeveloped Routing Vault 9/5/2023 10:44:41 AM Page 6 Mitigated Routing Vault 1 Width:80 ft. Length:89.3 ft. Depth:13 ft. Discharge Structure Riser Height:12 ft. Riser Diameter:24 in. Orifice 1 Diameter:1.969 in.Elevation:0 ft. Orifice 2 Diameter:1.625 in.Elevation:7 ft. Orifice 3 Diameter:1.781 in.Elevation:9.05 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.164 0.000 0.000 0.000 0.1444 0.164 0.023 0.040 0.000 0.2889 0.164 0.047 0.056 0.000 0.4333 0.164 0.071 0.069 0.000 0.5778 0.164 0.094 0.080 0.000 0.7222 0.164 0.118 0.089 0.000 0.8667 0.164 0.142 0.097 0.000 1.0111 0.164 0.165 0.105 0.000 1.1556 0.164 0.189 0.113 0.000 1.3000 0.164 0.213 0.119 0.000 1.4444 0.164 0.236 0.126 0.000 1.5889 0.164 0.260 0.132 0.000 1.7333 0.164 0.284 0.138 0.000 1.8778 0.164 0.308 0.144 0.000 2.0222 0.164 0.331 0.149 0.000 2.1667 0.164 0.355 0.154 0.000 2.3111 0.164 0.379 0.159 0.000 2.4556 0.164 0.402 0.164 0.000 2.6000 0.164 0.426 0.169 0.000 2.7444 0.164 0.450 0.174 0.000 2.8889 0.164 0.473 0.178 0.000 3.0333 0.164 0.497 0.183 0.000 3.1778 0.164 0.521 0.187 0.000 3.3222 0.164 0.544 0.191 0.000 3.4667 0.164 0.568 0.195 0.000 3.6111 0.164 0.592 0.199 0.000 3.7556 0.164 0.615 0.203 0.000 3.9000 0.164 0.639 0.207 0.000 4.0444 0.164 0.663 0.211 0.000 4.1889 0.164 0.687 0.215 0.000 4.3333 0.164 0.710 0.219 0.000 4.4778 0.164 0.734 0.222 0.000 4.6222 0.164 0.758 0.226 0.000 4.7667 0.164 0.781 0.229 0.000 4.9111 0.164 0.805 0.233 0.000 5.0556 0.164 0.829 0.236 0.000 5.2000 0.164 0.852 0.239 0.000 5.3444 0.164 0.876 0.243 0.000 Vault 9/5/2023 10:44:41 AM Page 7 5.4889 0.164 0.900 0.246 0.000 5.6333 0.164 0.923 0.249 0.000 5.7778 0.164 0.947 0.252 0.000 5.9222 0.164 0.971 0.256 0.000 6.0667 0.164 0.995 0.259 0.000 6.2111 0.164 1.018 0.262 0.000 6.3556 0.164 1.042 0.265 0.000 6.5000 0.164 1.066 0.268 0.000 6.6444 0.164 1.089 0.271 0.000 6.7889 0.164 1.113 0.274 0.000 6.9333 0.164 1.137 0.277 0.000 7.0778 0.164 1.160 0.299 0.000 7.2222 0.164 1.184 0.316 0.000 7.3667 0.164 1.208 0.328 0.000 7.5111 0.164 1.231 0.339 0.000 7.6556 0.164 1.255 0.349 0.000 7.8000 0.164 1.279 0.357 0.000 7.9444 0.164 1.302 0.366 0.000 8.0889 0.164 1.326 0.373 0.000 8.2333 0.164 1.350 0.381 0.000 8.3778 0.164 1.374 0.388 0.000 8.5222 0.164 1.397 0.395 0.000 8.6667 0.164 1.421 0.402 0.000 8.8111 0.164 1.445 0.408 0.000 8.9556 0.164 1.468 0.415 0.000 9.1000 0.164 1.492 0.440 0.000 9.2444 0.164 1.516 0.465 0.000 9.3889 0.164 1.539 0.483 0.000 9.5333 0.164 1.563 0.498 0.000 9.6778 0.164 1.587 0.512 0.000 9.8222 0.164 1.610 0.525 0.000 9.9667 0.164 1.634 0.537 0.000 10.111 0.164 1.658 0.549 0.000 10.256 0.164 1.681 0.560 0.000 10.400 0.164 1.705 0.571 0.000 10.544 0.164 1.729 0.581 0.000 10.689 0.164 1.753 0.591 0.000 10.833 0.164 1.776 0.601 0.000 10.978 0.164 1.800 0.611 0.000 11.122 0.164 1.824 0.620 0.000 11.267 0.164 1.847 0.629 0.000 11.411 0.164 1.871 0.638 0.000 11.556 0.164 1.895 0.646 0.000 11.700 0.164 1.918 0.655 0.000 11.844 0.164 1.942 0.663 0.000 11.989 0.164 1.966 0.671 0.000 12.133 0.164 1.989 1.710 0.000 12.278 0.164 2.013 3.747 0.000 12.422 0.164 2.037 6.221 0.000 12.567 0.164 2.061 8.712 0.000 12.711 0.164 2.084 10.81 0.000 12.856 0.164 2.108 12.28 0.000 13.000 0.164 2.132 13.19 0.000 13.144 0.164 2.155 14.21 0.000 13.289 0.000 0.000 15.04 0.000 Vault 9/5/2023 10:44:41 AM Page 8 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:7.48 Total Impervious Area:0.41 Mitigated Landuse Totals for POC #1 Total Pervious Area:3.78 Total Impervious Area:4.18 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.525386 5 year 0.821257 10 year 1.052694 25 year 1.387507 50 year 1.669031 100 year 1.97922 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.269563 5 year 0.40884 10 year 0.52718 25 year 0.7116 50 year 0.87794 100 year 1.07241 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.876 0.218 1950 0.818 0.262 1951 0.717 0.594 1952 0.343 0.188 1953 0.259 0.202 1954 0.423 0.243 1955 0.510 0.263 1956 0.536 0.281 1957 0.614 0.237 1958 0.369 0.243 Vault 9/5/2023 10:45:10 AM Page 9 1959 0.342 0.219 1960 0.714 0.527 1961 0.457 0.233 1962 0.231 0.177 1963 0.466 0.240 1964 0.492 0.226 1965 0.531 0.249 1966 0.348 0.215 1967 0.885 0.255 1968 0.542 0.216 1969 0.455 0.216 1970 0.485 0.224 1971 0.566 0.259 1972 0.724 0.374 1973 0.315 0.228 1974 0.563 0.243 1975 0.677 0.255 1976 0.489 0.250 1977 0.329 0.185 1978 0.419 0.235 1979 0.330 0.177 1980 1.266 0.413 1981 0.445 0.210 1982 0.948 0.479 1983 0.448 0.256 1984 0.324 0.195 1985 0.318 0.216 1986 0.655 0.381 1987 0.651 0.435 1988 0.262 0.205 1989 0.214 0.196 1990 2.029 0.550 1991 1.158 0.542 1992 0.437 0.232 1993 0.314 0.216 1994 0.193 0.165 1995 0.423 0.264 1996 1.096 0.596 1997 0.732 0.541 1998 0.457 0.219 1999 1.385 0.379 2000 0.485 0.257 2001 0.275 0.178 2002 0.674 0.400 2003 0.849 0.209 2004 0.851 0.664 2005 0.552 0.258 2006 0.534 0.245 2007 1.667 1.412 2008 1.440 1.314 2009 0.771 0.365 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 2.0286 1.4124 2 1.6669 1.3139 3 1.4402 0.6639 Vault 9/5/2023 10:45:10 AM Page 10 4 1.3853 0.5960 5 1.2656 0.5940 6 1.1576 0.5496 7 1.0956 0.5421 8 0.9482 0.5409 9 0.8848 0.5268 10 0.8764 0.4792 11 0.8514 0.4346 12 0.8486 0.4129 13 0.8184 0.3999 14 0.7713 0.3805 15 0.7317 0.3787 16 0.7235 0.3745 17 0.7174 0.3653 18 0.7143 0.2808 19 0.6766 0.2640 20 0.6735 0.2626 21 0.6552 0.2619 22 0.6505 0.2589 23 0.6145 0.2579 24 0.5656 0.2567 25 0.5627 0.2562 26 0.5523 0.2552 27 0.5419 0.2550 28 0.5357 0.2504 29 0.5336 0.2489 30 0.5308 0.2447 31 0.5098 0.2434 32 0.4917 0.2433 33 0.4887 0.2431 34 0.4854 0.2404 35 0.4853 0.2369 36 0.4656 0.2348 37 0.4573 0.2335 38 0.4565 0.2318 39 0.4550 0.2276 40 0.4475 0.2263 41 0.4448 0.2236 42 0.4373 0.2192 43 0.4234 0.2190 44 0.4225 0.2184 45 0.4187 0.2164 46 0.3692 0.2163 47 0.3484 0.2163 48 0.3434 0.2162 49 0.3425 0.2153 50 0.3300 0.2100 51 0.3294 0.2094 52 0.3237 0.2049 53 0.3183 0.2023 54 0.3153 0.1957 55 0.3139 0.1953 56 0.2746 0.1882 57 0.2622 0.1845 58 0.2591 0.1778 59 0.2306 0.1773 60 0.2144 0.1771 61 0.1930 0.1648 Vault 9/5/2023 10:45:10 AM Page 11 Vault 9/5/2023 10:45:10 AM Page 12 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2627 5950 5304 89 Pass 0.2769 5159 3859 74 Pass 0.2911 4436 3568 80 Pass 0.3053 3882 3382 87 Pass 0.3195 3364 3144 93 Pass 0.3337 2922 2855 97 Pass 0.3479 2545 2569 100 Pass 0.3621 2199 2207 100 Pass 0.3763 1948 1852 95 Pass 0.3905 1706 1567 91 Pass 0.4047 1501 1302 86 Pass 0.4190 1308 1031 78 Pass 0.4332 1167 959 82 Pass 0.4474 1025 891 86 Pass 0.4616 911 834 91 Pass 0.4758 819 767 93 Pass 0.4900 719 686 95 Pass 0.5042 608 586 96 Pass 0.5184 527 507 96 Pass 0.5326 455 438 96 Pass 0.5468 396 365 92 Pass 0.5610 341 313 91 Pass 0.5752 293 272 92 Pass 0.5894 255 229 89 Pass 0.6036 217 184 84 Pass 0.6178 193 148 76 Pass 0.6320 171 119 69 Pass 0.6462 143 95 66 Pass 0.6604 126 61 48 Pass 0.6747 112 27 24 Pass 0.6889 97 24 24 Pass 0.7031 85 22 25 Pass 0.7173 78 22 28 Pass 0.7315 63 17 26 Pass 0.7457 58 17 29 Pass 0.7599 55 16 29 Pass 0.7741 50 15 30 Pass 0.7883 48 15 31 Pass 0.8025 43 15 34 Pass 0.8167 41 15 36 Pass 0.8309 34 14 41 Pass 0.8451 33 13 39 Pass 0.8593 28 13 46 Pass 0.8735 27 13 48 Pass 0.8877 24 12 50 Pass 0.9019 24 12 50 Pass 0.9161 23 12 52 Pass 0.9303 22 12 54 Pass 0.9446 20 12 60 Pass 0.9588 19 12 63 Pass 0.9730 19 11 57 Pass 0.9872 15 10 66 Pass 1.0014 14 9 64 Pass Vault 9/5/2023 10:45:10 AM Page 13 1.0156 13 9 69 Pass 1.0298 13 9 69 Pass 1.0440 13 9 69 Pass 1.0582 13 9 69 Pass 1.0724 13 9 69 Pass 1.0866 13 9 69 Pass 1.1008 11 9 81 Pass 1.1150 10 9 90 Pass 1.1292 10 8 80 Pass 1.1434 9 8 88 Pass 1.1576 9 7 77 Pass 1.1718 8 6 75 Pass 1.1860 8 6 75 Pass 1.2003 8 6 75 Pass 1.2145 8 6 75 Pass 1.2287 8 6 75 Pass 1.2429 8 6 75 Pass 1.2571 8 6 75 Pass 1.2713 6 6 100 Pass 1.2855 6 6 100 Pass 1.2997 6 6 100 Pass 1.3139 6 4 66 Pass 1.3281 6 3 50 Pass 1.3423 6 3 50 Pass 1.3565 6 3 50 Pass 1.3707 6 2 33 Pass 1.3849 6 2 33 Pass 1.3991 5 2 40 Pass 1.4133 5 0 0 Pass 1.4275 5 0 0 Pass 1.4417 4 0 0 Pass 1.4559 4 0 0 Pass 1.4702 4 0 0 Pass 1.4844 4 0 0 Pass 1.4986 3 0 0 Pass 1.5128 3 0 0 Pass 1.5270 3 0 0 Pass 1.5412 3 0 0 Pass 1.5554 2 0 0 Pass 1.5696 2 0 0 Pass 1.5838 2 0 0 Pass 1.5980 2 0 0 Pass 1.6122 2 0 0 Pass 1.6264 2 0 0 Pass 1.6406 2 0 0 Pass 1.6548 2 0 0 Pass 1.6690 1 0 0 Pass Vault 9/5/2023 10:45:10 AM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.4349 acre-feet On-line facility target flow:0.2464 cfs. Adjusted for 15 min:0.2464 cfs. Off-line facility target flow:0.1352 cfs. Adjusted for 15 min:0.1352 cfs. Vault 9/5/2023 10:45:10 AM Page 15 LID Report Vault 9/5/2023 10:45:31 AM Page 16 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. Vault 9/5/2023 10:45:31 AM Page 17 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. Vault 9/5/2023 10:45:31 AM Page 18 Appendix Predeveloped Schematic Vault 9/5/2023 10:45:32 AM Page 19 Mitigated Schematic Vault 9/5/2023 10:45:33 AM Page 20 Predeveloped 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 Vault.wdm MESSU 25 PreVault.MES 27 PreVault.L61 28 PreVault.L62 30 POCVault1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 PERLND 17 IMPLND 4 IMPLND 1 IMPLND 8 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------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 C, Forest, Mod 1 1 1 1 27 0 17 C, Lawn, Mod 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 *** 11 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY Vault 9/5/2023 10:45:33 AM Page 21 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 0 0 0 0 0 0 0 0 0 0 0 17 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 11 0 4.5 0.08 400 0.1 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <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 11 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 1 ROADS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 1 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 0 0 4 0 0 4 1 9 1 0 0 4 0 0 0 1 9 8 0 0 4 0 0 0 1 9 END PRINT-INFO Vault 9/5/2023 10:45:33 AM Page 22 IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 4 0 0 0 0 0 1 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 1 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 1 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 1 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 11 6.7 COPY 501 12 PERLND 11 6.7 COPY 501 13 PERLND 17 0.78 COPY 501 12 PERLND 17 0.78 COPY 501 13 IMPLND 4 0.23 COPY 501 15 IMPLND 1 0.15 COPY 501 15 IMPLND 8 0.03 COPY 501 15 ******Routing****** END SCHEMATIC 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 Vault 9/5/2023 10:45:33 AM Page 23 <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 A1 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 1.167 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 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 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 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Vault 9/5/2023 10:45:33 AM Page 24 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 Vault.wdm MESSU 25 MitVault.MES 27 MitVault.L61 28 MitVault.L62 31 POCVault2.dat 30 POCVault1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 17 IMPLND 2 IMPLND 4 IMPLND 1 IMPLND 8 RCHRES 1 COPY 502 COPY 1 COPY 501 DISPLY 2 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 2 Basin 1 MAX 1 2 31 9 1 Vault 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 502 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------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY Vault 9/5/2023 10:45:33 AM Page 25 <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 17 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 ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 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 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <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 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 1 ROADS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 4 0 0 1 0 0 0 1 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 4 1 9 4 0 0 4 0 0 0 1 9 1 0 0 4 0 0 0 1 9 Vault 9/5/2023 10:45:33 AM Page 26 8 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 *** 2 0 0 0 0 0 4 0 0 0 0 0 1 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 4 400 0.01 0.1 0.1 1 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 4 0 0 1 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 4 0 0 1 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 17 3.78 RCHRES 1 2 PERLND 17 3.78 RCHRES 1 3 IMPLND 2 1.17 RCHRES 1 5 IMPLND 4 1.99 RCHRES 1 5 IMPLND 1 0.47 RCHRES 1 5 IMPLND 8 0.55 RCHRES 1 5 Basin 1*** PERLND 17 3.78 COPY 502 12 PERLND 17 3.78 COPY 502 13 IMPLND 2 1.17 COPY 502 15 IMPLND 4 1.99 COPY 502 15 IMPLND 1 0.47 COPY 502 15 IMPLND 8 0.55 COPY 502 15 ******Routing****** PERLND 17 3.78 COPY 1 12 IMPLND 2 1.17 COPY 1 15 IMPLND 4 1.99 COPY 1 15 IMPLND 1 0.47 COPY 1 15 IMPLND 8 0.55 COPY 1 15 PERLND 17 3.78 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK Vault 9/5/2023 10:45:33 AM Page 27 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 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 *** 1 Vault 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.02 0.0 0.0 0.5 0.0 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 <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.164004 0.000000 0.000000 0.144444 0.164004 0.023689 0.039975 0.288889 0.164004 0.047379 0.056533 0.433333 0.164004 0.071068 0.069239 0.577778 0.164004 0.094758 0.079950 0.722222 0.164004 0.118447 0.089387 0.866667 0.164004 0.142137 0.097919 1.011111 0.164004 0.165826 0.105764 1.155556 0.164004 0.189515 0.113067 Vault 9/5/2023 10:45:33 AM Page 28 1.300000 0.164004 0.213205 0.119926 1.444444 0.164004 0.236894 0.126413 1.588889 0.164004 0.260584 0.132583 1.733333 0.164004 0.284273 0.138478 1.877778 0.164004 0.307962 0.144133 2.022222 0.164004 0.331652 0.149573 2.166667 0.164004 0.355341 0.154823 2.311111 0.164004 0.379031 0.159901 2.455556 0.164004 0.402720 0.164822 2.600000 0.164004 0.426410 0.169600 2.744444 0.164004 0.450099 0.174248 2.888889 0.164004 0.473788 0.178774 3.033333 0.164004 0.497478 0.183189 3.177778 0.164004 0.521167 0.187500 3.322222 0.164004 0.544857 0.191714 3.466667 0.164004 0.568546 0.195838 3.611111 0.164004 0.592235 0.199876 3.755556 0.164004 0.615925 0.203834 3.900000 0.164004 0.639614 0.207717 4.044444 0.164004 0.663304 0.211529 4.188889 0.164004 0.686993 0.215273 4.333333 0.164004 0.710683 0.218953 4.477778 0.164004 0.734372 0.222572 4.622222 0.164004 0.758061 0.226134 4.766667 0.164004 0.781751 0.229640 4.911111 0.164004 0.805440 0.233093 5.055556 0.164004 0.829130 0.236496 5.200000 0.164004 0.852819 0.239851 5.344444 0.164004 0.876509 0.243159 5.488889 0.164004 0.900198 0.246423 5.633333 0.164004 0.923887 0.249645 5.777778 0.164004 0.947577 0.252825 5.922222 0.164004 0.971266 0.255966 6.066667 0.164004 0.994956 0.259069 6.211111 0.164004 1.018645 0.262135 6.355556 0.164004 1.042334 0.265165 6.500000 0.164004 1.066024 0.268162 6.644444 0.164004 1.089713 0.271125 6.788889 0.164004 1.113403 0.274056 6.933333 0.164004 1.137092 0.276956 7.077778 0.164004 1.160782 0.299811 7.222222 0.164004 1.184471 0.316447 7.366667 0.164004 1.208160 0.328871 7.511111 0.164004 1.231850 0.339495 7.655556 0.164004 1.255539 0.349043 7.800000 0.164004 1.279229 0.357849 7.944444 0.164004 1.302918 0.366103 8.088889 0.164004 1.326607 0.373922 8.233333 0.164004 1.350297 0.381386 8.377778 0.164004 1.373986 0.388553 8.522222 0.164004 1.397676 0.395466 8.666667 0.164004 1.421365 0.402157 8.811111 0.164004 1.445055 0.408652 8.955556 0.164004 1.468744 0.414972 9.100000 0.164004 1.492433 0.440388 9.244444 0.164004 1.516123 0.465123 9.388889 0.164004 1.539812 0.483168 9.533333 0.164004 1.563502 0.498673 9.677778 0.164004 1.587191 0.512692 9.822222 0.164004 1.610881 0.525688 9.966667 0.164004 1.634570 0.537918 10.11111 0.164004 1.658259 0.549542 10.25556 0.164004 1.681949 0.560668 10.40000 0.164004 1.705638 0.571372 10.54444 0.164004 1.729328 0.581713 10.68889 0.164004 1.753017 0.591735 10.83333 0.164004 1.776706 0.601474 10.97778 0.164004 1.800396 0.610960 11.12222 0.164004 1.824085 0.620214 11.26667 0.164004 1.847775 0.629259 Vault 9/5/2023 10:45:33 AM Page 29 11.41111 0.164004 1.871464 0.638110 11.55556 0.164004 1.895154 0.646783 11.70000 0.164004 1.918843 0.655290 11.84444 0.164004 1.942532 0.663642 11.98889 0.164004 1.966222 0.671850 12.13333 0.164004 1.989911 1.710793 12.27778 0.164004 2.013601 3.747794 12.42222 0.164004 2.037290 6.221405 12.56667 0.164004 2.060979 8.711970 12.71111 0.164004 2.084669 10.81939 12.85556 0.164004 2.108358 12.28694 13.00000 0.164004 2.132048 13.18983 13.14444 0.164004 2.155737 14.21092 END FTABLE 1 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 1.167 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 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 2 OUTPUT MEAN 1 1 48.4 WDM 702 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 802 FLOW ENGL REPL RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1001 STAG ENGL REPL 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> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 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 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK Vault 9/5/2023 10:45:33 AM Page 30 END RUN Vault 9/5/2023 10:45:33 AM Page 31 Predeveloped HSPF Message File Vault 9/5/2023 10:45:33 AM Page 32 Mitigated HSPF Message File Vault 9/5/2023 10:45:33 AM Page 33 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. 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 WWHM2012 PROJECT REPORT Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 2 General Model Information WWHM2012 Project Name:Sunset Blvd Sidewalk Site Name: Site Address: City: Report Date:7/7/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.167 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.16 Pervious Total 0.16 Impervious Land Use acre Impervious Total 0 Basin Total 0.16 Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.08 Pervious Total 0.08 Impervious Land Use acre ROOF TOPS FLAT 0.08 Impervious Total 0.08 Basin Total 0.16 Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 5 Routing Elements Predeveloped Routing Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 6 Mitigated Routing Sunset Blvd Sidewalk 7/7/2023 9:40:18 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.16 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.08 Total Impervious Area:0.08 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.006594 5 year 0.011208 10 year 0.014876 25 year 0.020211 50 year 0.024697 100 year 0.029625 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.047603 5 year 0.063955 10 year 0.075361 25 year 0.090453 50 year 0.102201 100 year 0.114391 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.010 0.071 1950 0.010 0.062 1951 0.013 0.042 1952 0.004 0.028 1953 0.004 0.031 1954 0.005 0.040 1955 0.008 0.043 1956 0.007 0.041 1957 0.007 0.052 1958 0.006 0.037 Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 8 1959 0.005 0.032 1960 0.010 0.043 1961 0.005 0.042 1962 0.003 0.031 1963 0.005 0.044 1964 0.007 0.037 1965 0.005 0.053 1966 0.004 0.032 1967 0.011 0.061 1968 0.006 0.068 1969 0.006 0.050 1970 0.005 0.046 1971 0.006 0.054 1972 0.010 0.064 1973 0.005 0.027 1974 0.006 0.052 1975 0.008 0.053 1976 0.006 0.039 1977 0.002 0.041 1978 0.005 0.046 1979 0.003 0.059 1980 0.018 0.074 1981 0.004 0.050 1982 0.011 0.076 1983 0.007 0.052 1984 0.004 0.035 1985 0.002 0.048 1986 0.010 0.042 1987 0.010 0.060 1988 0.004 0.031 1989 0.003 0.042 1990 0.030 0.108 1991 0.014 0.083 1992 0.005 0.035 1993 0.005 0.028 1994 0.002 0.027 1995 0.006 0.041 1996 0.017 0.054 1997 0.012 0.049 1998 0.005 0.042 1999 0.020 0.106 2000 0.005 0.049 2001 0.001 0.047 2002 0.007 0.067 2003 0.011 0.056 2004 0.011 0.098 2005 0.007 0.042 2006 0.007 0.039 2007 0.023 0.098 2008 0.024 0.081 2009 0.010 0.052 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0305 0.1076 2 0.0237 0.1063 3 0.0233 0.0977 Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 9 4 0.0196 0.0975 5 0.0180 0.0835 6 0.0172 0.0808 7 0.0139 0.0759 8 0.0129 0.0744 9 0.0123 0.0710 10 0.0112 0.0678 11 0.0112 0.0665 12 0.0106 0.0637 13 0.0105 0.0623 14 0.0105 0.0611 15 0.0103 0.0595 16 0.0103 0.0587 17 0.0101 0.0563 18 0.0101 0.0542 19 0.0098 0.0536 20 0.0096 0.0533 21 0.0081 0.0529 22 0.0079 0.0525 23 0.0075 0.0524 24 0.0073 0.0520 25 0.0071 0.0516 26 0.0069 0.0503 27 0.0067 0.0495 28 0.0066 0.0493 29 0.0065 0.0491 30 0.0065 0.0483 31 0.0062 0.0471 32 0.0062 0.0457 33 0.0061 0.0456 34 0.0061 0.0438 35 0.0058 0.0433 36 0.0058 0.0433 37 0.0055 0.0423 38 0.0053 0.0422 39 0.0051 0.0419 40 0.0051 0.0419 41 0.0050 0.0417 42 0.0049 0.0417 43 0.0049 0.0413 44 0.0048 0.0408 45 0.0047 0.0405 46 0.0047 0.0400 47 0.0046 0.0390 48 0.0046 0.0389 49 0.0043 0.0373 50 0.0042 0.0367 51 0.0041 0.0354 52 0.0041 0.0348 53 0.0040 0.0321 54 0.0036 0.0321 55 0.0034 0.0314 56 0.0028 0.0308 57 0.0027 0.0306 58 0.0025 0.0285 59 0.0024 0.0282 60 0.0021 0.0270 61 0.0012 0.0266 Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 10 Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 11 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0033 16206 89149 550 Fail 0.0035 14119 82903 587 Fail 0.0037 12194 77321 634 Fail 0.0039 10510 72209 687 Fail 0.0042 9163 67524 736 Fail 0.0044 7965 63289 794 Fail 0.0046 6951 59247 852 Fail 0.0048 6141 55461 903 Fail 0.0050 5450 52125 956 Fail 0.0052 4862 48959 1006 Fail 0.0055 4361 46007 1054 Fail 0.0057 3918 43205 1102 Fail 0.0059 3482 40660 1167 Fail 0.0061 3084 38350 1243 Fail 0.0063 2731 36190 1325 Fail 0.0065 2415 34179 1415 Fail 0.0068 2160 32254 1493 Fail 0.0070 1931 30436 1576 Fail 0.0072 1761 28768 1633 Fail 0.0074 1597 27164 1700 Fail 0.0076 1391 25645 1843 Fail 0.0078 1246 24255 1946 Fail 0.0081 1118 22950 2052 Fail 0.0083 1035 21774 2103 Fail 0.0085 942 20619 2188 Fail 0.0087 875 19519 2230 Fail 0.0089 788 18536 2352 Fail 0.0091 713 17599 2468 Fail 0.0093 631 16703 2647 Fail 0.0096 545 15826 2903 Fail 0.0098 465 15060 3238 Fail 0.0100 391 14335 3666 Fail 0.0102 351 13646 3887 Fail 0.0104 309 12981 4200 Fail 0.0106 267 12371 4633 Fail 0.0109 218 11755 5392 Fail 0.0111 184 11169 6070 Fail 0.0113 153 10671 6974 Fail 0.0115 126 10190 8087 Fail 0.0117 114 9736 8540 Fail 0.0119 94 9287 9879 Fail 0.0122 80 8913 11141 Fail 0.0124 67 8485 12664 Fail 0.0126 60 8089 13481 Fail 0.0128 49 7773 15863 Fail 0.0130 44 7452 16936 Fail 0.0132 41 7110 17341 Fail 0.0135 35 6787 19391 Fail 0.0137 31 6494 20948 Fail 0.0139 25 6192 24768 Fail 0.0141 20 5942 29710 Fail 0.0143 18 5666 31477 Fail 0.0145 12 5420 45166 Fail 0.0148 12 5204 43366 Fail Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 12 0.0150 11 5009 45536 Fail 0.0152 11 4770 43363 Fail 0.0154 10 4590 45900 Fail 0.0156 9 4391 48788 Fail 0.0158 9 4207 46744 Fail 0.0161 9 4062 45133 Fail 0.0163 9 3910 43444 Fail 0.0165 9 3752 41688 Fail 0.0167 9 3628 40311 Fail 0.0169 9 3467 38522 Fail 0.0171 9 3332 37022 Fail 0.0173 8 3204 40050 Fail 0.0176 8 3082 38525 Fail 0.0178 8 2977 37212 Fail 0.0180 7 2860 40857 Fail 0.0182 6 2742 45700 Fail 0.0184 6 2650 44166 Fail 0.0186 6 2556 42600 Fail 0.0189 6 2468 41133 Fail 0.0191 6 2376 39600 Fail 0.0193 6 2280 38000 Fail 0.0195 6 2222 37033 Fail 0.0197 5 2156 43120 Fail 0.0199 5 2092 41840 Fail 0.0202 5 2024 40480 Fail 0.0204 5 1948 38960 Fail 0.0206 5 1878 37560 Fail 0.0208 5 1819 36380 Fail 0.0210 5 1755 35100 Fail 0.0212 5 1702 34040 Fail 0.0215 4 1646 41150 Fail 0.0217 4 1594 39850 Fail 0.0219 4 1548 38700 Fail 0.0221 4 1509 37725 Fail 0.0223 4 1465 36625 Fail 0.0225 4 1421 35525 Fail 0.0228 4 1378 34450 Fail 0.0230 4 1345 33625 Fail 0.0232 4 1309 32725 Fail 0.0234 3 1273 42433 Fail 0.0236 3 1236 41200 Fail 0.0238 1 1193 119300 Fail 0.0240 1 1157 115700 Fail 0.0243 1 1127 112700 Fail 0.0245 1 1101 110100 Fail 0.0247 1 1067 106700 Fail 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. Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.4349 acre-feet On-line facility target flow:0.2464 cfs. Adjusted for 15 min:0.2464 cfs. Off-line facility target flow:0.1352 cfs. Adjusted for 15 min:0.1352 cfs. Sunset Blvd Sidewalk 7/7/2023 9:40:46 AM Page 14 LID Report Sunset Blvd Sidewalk 7/7/2023 9:41:06 AM Page 15 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. Sunset Blvd Sidewalk 7/7/2023 9:41:06 AM Page 16 Appendix Predeveloped Schematic Sunset Blvd Sidewalk 7/7/2023 9:41:07 AM Page 17 Mitigated Schematic Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 18 Predeveloped 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 Sunset Blvd Sidewalk.wdm MESSU 25 PreSunset Blvd Sidewalk.MES 27 PreSunset Blvd Sidewalk.L61 28 PreSunset Blvd Sidewalk.L62 30 POCSunset Blvd Sidewalk1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 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------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 11 C, Forest, Mod 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 *** 11 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 ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 19 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 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 11 0 4.5 0.08 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <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 11 0 0 0 0 2.5 1 0 END PWAT-STATE1 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-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 20 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 11 0.16 COPY 501 12 PERLND 11 0.16 COPY 501 13 ******Routing****** END SCHEMATIC 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 A1 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 1.167 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 IMPLND 1 999 EXTNL PREC Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 21 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 Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 22 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 Sunset Blvd Sidewalk.wdm MESSU 25 MitSunset Blvd Sidewalk.MES 27 MitSunset Blvd Sidewalk.L61 28 MitSunset Blvd Sidewalk.L62 30 POCSunset Blvd Sidewalk1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 17 IMPLND 4 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------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 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 *** 17 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 ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 23 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 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 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <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 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 4 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 24 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 17 0.08 COPY 501 12 PERLND 17 0.08 COPY 501 13 IMPLND 4 0.08 COPY 501 15 ******Routing****** END SCHEMATIC 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 A1 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 Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 25 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 1.167 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 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> <-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 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 26 Predeveloped HSPF Message File Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 27 Mitigated HSPF Message File Sunset Blvd Sidewalk 7/7/2023 9:41:09 AM Page 28 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. 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 WWHM2012 PROJECT REPORT TESC 7/25/2023 10:27:36 AM Page 2 General Model Information WWHM2012 Project Name:TESC Site Name: Site Address: City: Report Date:7/25/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.167 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year TESC 7/25/2023 10:27:36 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 6.7 C, Lawn, Mod 0.78 Pervious Total 7.48 Impervious Land Use acre ROOF TOPS FLAT 0.23 ROADS FLAT 0.15 SIDEWALKS FLAT 0.03 Impervious Total 0.41 Basin Total 7.89 TESC 7/25/2023 10:27:36 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 3.78 Pervious Total 3.78 Impervious Land Use acre ROADS MOD 1.17 ROOF TOPS FLAT 1.99 ROADS FLAT 0.47 SIDEWALKS FLAT 0.55 Impervious Total 4.18 Basin Total 7.96 TESC 7/25/2023 10:27:36 AM Page 5 Routing Elements Predeveloped Routing TESC 7/25/2023 10:27:36 AM Page 6 Mitigated Routing TESC 7/25/2023 10:27:36 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:7.48 Total Impervious Area:0.41 Mitigated Landuse Totals for POC #1 Total Pervious Area:3.78 Total Impervious Area:4.18 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.525386 5 year 0.821257 10 year 1.052694 25 year 1.387507 50 year 1.669031 100 year 1.97922 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 2.489529 5 year 3.324919 10 year 3.917367 25 year 4.712206 50 year 5.338809 100 year 5.995682 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.876 3.676 1950 0.818 3.197 1951 0.717 2.176 1952 0.343 1.484 1953 0.259 1.668 1954 0.423 2.086 1955 0.510 2.307 1956 0.536 2.107 1957 0.614 2.690 1958 0.369 1.944 TESC 7/25/2023 10:28:17 AM Page 8 1959 0.342 1.771 1960 0.714 2.284 1961 0.457 2.147 1962 0.231 1.655 1963 0.466 2.298 1964 0.492 1.918 1965 0.531 2.729 1966 0.348 1.691 1967 0.885 3.209 1968 0.542 3.662 1969 0.455 2.573 1970 0.485 2.393 1971 0.566 2.825 1972 0.724 3.226 1973 0.315 1.430 1974 0.563 2.729 1975 0.677 2.711 1976 0.489 2.081 1977 0.329 2.151 1978 0.419 2.495 1979 0.330 3.176 1980 1.266 4.031 1981 0.445 2.560 1982 0.948 3.893 1983 0.448 2.717 1984 0.324 1.788 1985 0.318 2.475 1986 0.655 2.165 1987 0.651 3.113 1988 0.262 1.640 1989 0.214 2.420 1990 2.029 5.428 1991 1.158 4.311 1992 0.437 1.827 1993 0.314 1.700 1994 0.193 1.469 1995 0.423 2.158 1996 1.096 2.893 1997 0.732 2.532 1998 0.457 2.210 1999 1.385 5.551 2000 0.485 2.540 2001 0.275 2.553 2002 0.674 3.375 2003 0.849 3.050 2004 0.851 5.155 2005 0.552 2.139 2006 0.534 2.007 2007 1.667 4.963 2008 1.440 4.122 2009 0.771 2.802 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 2.0286 5.5506 2 1.6669 5.4280 3 1.4402 5.1549 TESC 7/25/2023 10:28:17 AM Page 9 4 1.3853 4.9627 5 1.2656 4.3110 6 1.1576 4.1222 7 1.0956 4.0310 8 0.9482 3.8933 9 0.8848 3.6764 10 0.8764 3.6619 11 0.8514 3.3749 12 0.8486 3.2257 13 0.8184 3.2087 14 0.7713 3.1966 15 0.7317 3.1762 16 0.7235 3.1135 17 0.7174 3.0497 18 0.7143 2.8927 19 0.6766 2.8245 20 0.6735 2.8020 21 0.6552 2.7291 22 0.6505 2.7289 23 0.6145 2.7174 24 0.5656 2.7115 25 0.5627 2.6897 26 0.5523 2.5733 27 0.5419 2.5602 28 0.5357 2.5530 29 0.5336 2.5398 30 0.5308 2.5321 31 0.5098 2.4952 32 0.4917 2.4750 33 0.4887 2.4201 34 0.4854 2.3932 35 0.4853 2.3070 36 0.4656 2.2978 37 0.4573 2.2842 38 0.4565 2.2103 39 0.4550 2.1755 40 0.4475 2.1646 41 0.4448 2.1577 42 0.4373 2.1513 43 0.4234 2.1469 44 0.4225 2.1389 45 0.4187 2.1075 46 0.3692 2.0864 47 0.3484 2.0809 48 0.3434 2.0068 49 0.3425 1.9436 50 0.3300 1.9183 51 0.3294 1.8275 52 0.3237 1.7879 53 0.3183 1.7714 54 0.3153 1.7004 55 0.3139 1.6915 56 0.2746 1.6676 57 0.2622 1.6554 58 0.2591 1.6395 59 0.2306 1.4838 60 0.2144 1.4692 61 0.1930 1.4302 TESC 7/25/2023 10:28:17 AM Page 10 TESC 7/25/2023 10:28:17 AM Page 11 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.2627 5950 51226 860 Fail 0.2769 5159 47483 920 Fail 0.2911 4436 43655 984 Fail 0.3053 3882 40575 1045 Fail 0.3195 3364 37687 1120 Fail 0.3337 2922 35163 1203 Fail 0.3479 2545 32789 1288 Fail 0.3621 2199 30351 1380 Fail 0.3763 1948 28276 1451 Fail 0.3905 1706 26330 1543 Fail 0.4047 1501 24576 1637 Fail 0.4190 1308 22950 1754 Fail 0.4332 1167 21385 1832 Fail 0.4474 1025 19988 1950 Fail 0.4616 911 18730 2055 Fail 0.4758 819 17614 2150 Fail 0.4900 719 16448 2287 Fail 0.5042 608 15383 2530 Fail 0.5184 527 14437 2739 Fail 0.5326 455 13603 2989 Fail 0.5468 396 12799 3232 Fail 0.5610 341 11963 3508 Fail 0.5752 293 11274 3847 Fail 0.5894 255 10639 4172 Fail 0.6036 217 10044 4628 Fail 0.6178 193 9494 4919 Fail 0.6320 171 8977 5249 Fail 0.6462 143 8476 5927 Fail 0.6604 126 8021 6365 Fail 0.6747 112 7587 6774 Fail 0.6889 97 7146 7367 Fail 0.7031 85 6716 7901 Fail 0.7173 78 6378 8176 Fail 0.7315 63 6064 9625 Fail 0.7457 58 5741 9898 Fail 0.7599 55 5431 9874 Fail 0.7741 50 5112 10224 Fail 0.7883 48 4883 10172 Fail 0.8025 43 4652 10818 Fail 0.8167 41 4421 10782 Fail 0.8309 34 4199 12350 Fail 0.8451 33 3974 12042 Fail 0.8593 28 3788 13528 Fail 0.8735 27 3615 13388 Fail 0.8877 24 3454 14391 Fail 0.9019 24 3296 13733 Fail 0.9161 23 3129 13604 Fail 0.9303 22 2982 13554 Fail 0.9446 20 2838 14189 Fail 0.9588 19 2710 14263 Fail 0.9730 19 2569 13521 Fail 0.9872 15 2464 16426 Fail 1.0014 14 2351 16792 Fail 1.0156 13 2246 17276 Fail TESC 7/25/2023 10:28:17 AM Page 12 1.0298 13 2147 16515 Fail 1.0440 13 2069 15915 Fail 1.0582 13 1983 15253 Fail 1.0724 13 1898 14600 Fail 1.0866 13 1826 14046 Fail 1.1008 11 1760 16000 Fail 1.1150 10 1692 16920 Fail 1.1292 10 1621 16210 Fail 1.1434 9 1558 17311 Fail 1.1576 9 1500 16666 Fail 1.1718 8 1448 18100 Fail 1.1860 8 1392 17400 Fail 1.2003 8 1350 16875 Fail 1.2145 8 1310 16375 Fail 1.2287 8 1257 15712 Fail 1.2429 8 1217 15212 Fail 1.2571 8 1176 14700 Fail 1.2713 6 1127 18783 Fail 1.2855 6 1096 18266 Fail 1.2997 6 1066 17766 Fail 1.3139 6 1017 16950 Fail 1.3281 6 983 16383 Fail 1.3423 6 941 15683 Fail 1.3565 6 902 15033 Fail 1.3707 6 871 14516 Fail 1.3849 6 844 14066 Fail 1.3991 5 813 16260 Fail 1.4133 5 789 15780 Fail 1.4275 5 764 15280 Fail 1.4417 4 749 18725 Fail 1.4559 4 724 18100 Fail 1.4702 4 696 17400 Fail 1.4844 4 667 16675 Fail 1.4986 3 642 21400 Fail 1.5128 3 618 20600 Fail 1.5270 3 600 20000 Fail 1.5412 3 578 19266 Fail 1.5554 2 562 28100 Fail 1.5696 2 554 27700 Fail 1.5838 2 538 26900 Fail 1.5980 2 518 25900 Fail 1.6122 2 510 25500 Fail 1.6264 2 494 24700 Fail 1.6406 2 484 24200 Fail 1.6548 2 469 23450 Fail 1.6690 1 453 45300 Fail 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. TESC 7/25/2023 10:28:17 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.4349 acre-feet On-line facility target flow:0.2464 cfs. Adjusted for 15 min:0.2464 cfs. Off-line facility target flow:0.1352 cfs. Adjusted for 15 min:0.1352 cfs. TESC 7/25/2023 10:28:17 AM Page 14 LID Report TESC 7/25/2023 10:28:37 AM Page 15 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. TESC 7/25/2023 10:28:37 AM Page 16 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. TESC 7/25/2023 10:28:37 AM Page 17 Appendix Predeveloped Schematic TESC 7/25/2023 10:28:38 AM Page 18 Mitigated Schematic TESC 7/25/2023 10:28:39 AM Page 19 Predeveloped UCI File TESC 7/25/2023 10:28:39 AM Page 20 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 TESC.wdm MESSU 25 MitTESC.MES 27 MitTESC.L61 28 MitTESC.L62 30 POCTESC1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 17 IMPLND 2 IMPLND 4 IMPLND 1 IMPLND 8 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------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 17 C, Lawn, Mod 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 *** 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR TESC 7/25/2023 10:28:39 AM Page 21 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 17 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 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <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 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 1 ROADS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 4 0 0 1 0 0 0 1 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 4 1 9 4 0 0 4 0 0 0 1 9 1 0 0 4 0 0 0 1 9 8 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 *** 2 0 0 0 0 0 TESC 7/25/2023 10:28:39 AM Page 22 4 0 0 0 0 0 1 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 4 400 0.01 0.1 0.1 1 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 4 0 0 1 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 4 0 0 1 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 17 3.78 COPY 501 12 PERLND 17 3.78 COPY 501 13 IMPLND 2 1.17 COPY 501 15 IMPLND 4 1.99 COPY 501 15 IMPLND 1 0.47 COPY 501 15 IMPLND 8 0.55 COPY 501 15 ******Routing****** END SCHEMATIC 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 *** TESC 7/25/2023 10:28:39 AM Page 23 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 A1 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 1.167 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 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> <-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 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN TESC 7/25/2023 10:28:39 AM Page 24 Predeveloped HSPF Message File TESC 7/25/2023 10:28:39 AM Page 25 Mitigated HSPF Message File TESC 7/25/2023 10:28:39 AM Page 26 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. 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 Core Design, Inc. TOWNS ON 12TH Page 10-5 Appendix B Special Reports Core Design, Inc. TOWNS ON 12TH Page 10-6 Insert reports referenced in section 6