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Towne Place Hotel 2019-0927 Technical Information Report Technical Information Report Town Place Hotel Federal Way, WA Prepared For: HC FW, LLC 3926 Aurora Ave. North Seattle, WA 98103 Prepared By: SCJ Alliance 8730 Tallon Lane NE, Suite 200 Lacey, WA 98516 360-352-1465 September 2019 SCJ Alliance September 2019 Technical Information Report Project Information Project: Town Place Hotel Prepared for: HC FW, LLC 3926 Aurora Ave. North Seattle, WA 98103 Contact Name: Han Kim Contact Phone: 206-441-0266 Reviewing Agency Jurisdiction: City of Federal Way Project Representative Prepared by: SCJ Alliance 8730 Tallon Lane NE, Suite 200 Lacey, WA 98516 360.352.1465 scjalliance.com Contact: Tyrell Bradley, PE Project Reference: SCJ #3278.01 Path: N:\Projects\3278 HC FW, LLC\3278.01 Town Place Hotel Federal Way\Phase 02 - Construction Documents\Design\Storm\Technical Information Report\2019-xxxx Stormwater Site Plan.docx Town Place Hotel Technical Information Report SCJ Alliance September 2019 PROJECT ENGINEER’S CERTIFICATION I hereby certify that this Technical Information Report (TIR) for the Town Place Hotel project has been prepared by me or under my supervision and meets the minimum standards of the City of Federal Way and normal standards of engineering practice. I hereby acknowledge and agree that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me. Prepared by: Mallory Dobbs, EIT Date Mallory.Dobbs@scjalliance.com (360) 352-1465 Approved by: Tyrell, Bradley, PE Date Tyrell.Bradley@scjalliance.com (360) 352-1465 09/27/2019 09/27/2019 Town Place Hotel Technical Information Report Town Place Hotel 1 of 7 Technical Information Report TABLE OF CONTENTS 1. Project Overview ........................................................................................................ 3 2. Conditions and Requirements Summary ..................................................................... 3 2.1 Summary of Compliance On-Site .......................................................................................... 4 3. Offsite Analysis .......................................................................................................... 5 3.1 Level 1 Downstream Analysis ................................................................................................ 5 4. Flow Control, Low Impact development (LID) and Water Quality Facility Analysis and Design ................................................................................................................................ 6 4.1 Existing Site Hydrology (Part A) ............................................................................................. 6 4.2 Developed Site Hydrology (Part B) ........................................................................................ 6 4.3 Performance Standards (Part C) ............................................................................................ 7 4.4 Flow Control System (Part D) ................................................................................................ 7 4.5 Water Quality System (Part E) ............................................................................................... 7 5. Conveyance System Analysis and Design ..................................................................... 8 6. Special Reports and Studies ........................................................................................ 8 7. Other Permits ............................................................................................................. 8 8. CSWPP Plan Analysis and Design................................................................................. 8 8.1 Esc Plan Analysis and Design (Part A) .................................................................................... 8 8.2 SWPPS Plan Design (Part B) ................................................................................................... 9 9. Bond Quantities, Facility Summaries, and Declaration of Covenant ............................. 9 10. Operations and Maintenance Manual ......................................................................... 9 LIST OF TABLES Table 1: Land Type Designations Existing vs. Proposed ............................................................................ 7 Town Place Hotel Technical Information Report Town Place Hotel 2 of 7 Technical Information Report LIST OF FIGURES Figure 1: Existing Conditions (1990) Figure 2: Existing Conditions (2018) .................................. 6 LIST OF APPENDICES Appendix 1: Site Vicinity Map Appendix 2: Determination of Minimum Requirements Worksheet Appendix 3: Basin Map Exhibits Appendix 4: Preliminary Construction Plans Appendix 5: Special Reports Appendix 6: Operations and Maintenance Manual Appendix 7: Construction Stormwater Pollution Prevention Plan Appendix 8: FEMA Flood Insurance Map Appendix 9: Design Calculations and Computation Appendix 10: King County Surface Water Manual Worksheets Appendix 11: Declaration of Covenant Town Place Hotel 3 of 9 Technical Information Report 1. PROJECT OVERVIEW The following report was prepared for the Town Place Hotel project in Federal Way, WA. This report was prepared to comply with the minimum technical standards and requirements that are set forth in the 2016 King County Surface Water Design Manual (KCSWDM) and the 2017 City of Federal Way Addendum to The King County Surface Water Design Manual. Project Proponent: HC FW, LLC Parcel Numbers: 2021049044 Total Parcel Area: 2.80 Acres Current Zoning: CE – Commercial Enterprise Required Permits: Grading, Utility, Paving, Building, etc. Site Address: 34839 Pacific Hwy South Section, Township, Range: Section 20, Township 21 N, Range 4 E The proposed Town Place Hotel is located on one parcel that contains 2.80 acres. The project is located to the south west of S 348th Street and Pacific Hwy South in Federal Way, WA. The proposed construction includes the 4- story hotel building, as well as associated parking lot, utilities, and stormwater improvements disturbing approximately 1.36 acres. Specifically, the proposed site improvements/construction activities for this project include the following: · Site preparation, grading, and erosion control activities · Construction of Town Place Hotel · Construction of parking lot · Construction/installation of on-site water quality and flow control facilities · Extension of available utilities (i.e., water, sewer, etc.) A site vicinity map of the proposed project location is enclosed herein as Appendix 1. A worksheet for determining the number of Minimum Requirements for this project per the KCSWDM has been prepared and enclosed herein as Appendix 2. Per Figure 1.1.2.A, the proposed project will require a Full Drainage Review. 2. CONDITIONS AND REQUIREMENTS SUMMARY The proposed project improvements will result in more than 2,000 square feet of new impervious surface. In accordance with Section 1.1.2 of the KCSWDM, a Full Drainage Review is required for this project. As a result, Core Requirements 1-9 and Special Requirements 1-5 will need to be addressed. See below for the summary of compliance with these requirements. Town Place Hotel 4 of 9 Technical Information Report 2.1 SUMMARY OF COMPLIANCE ON-SITE The stormwater design complies with the 9 core requirements and 5 special requirements as follows: Core Requirement #1 – Discharge at the Natural Location – Currently, stormwater runoff within the parcel sheet flows to the center of the parcel and into an existing stream that runs through the parcel. After construction, the stormwater runoff from the proposed improvements will be collected, treated, detained and released into the stream at the predeveloped rates. A level spreader will be used at the outfall of the detention system to dissipate the water so that no erosion will occur in or near the stream. The areas to the west of the project will remain undisturbed throughout construction and will continue to follow the same drainage patterns. Core Requirement #2 – Offsite Analysis – A Level 1 upstream and downstream analysis for this project has been completed and included in Section 3 of this TIR. Core Requirement #3 – Flow Control Facilities – According to the City of Federal Way Flow Control Applications Map (see Appendix 3), the project is located within a Conservation Flow Control Area. There are no known drainage problems on the site or downstream from the site. Therefore, the flow control performance criteria requirement is to apply the historic site conditions Level 2 flow control standard which matches historic durations for 50% of the 2-year through 50-year peaks AND matches historic 2- and 10- year peaks. The historic site conditions are assumed to be forested. Flow control for the proposed project improvements will be provided by an underground detention facility and flow control release structure sized using the 2012 Western Washington Hydrology Model (WWHM), which is an approved continuous runoff model according to the KCSWDM. Core Requirement #4 – Conveyance System – All on-site stormwater conveyance systems will be designed to route the 25-year peak flow event. A hydraulic analysis will be completed and provided in Section 5 of this report at the time of the civil permit submittal. Stormwater runoff release flows from the site are anticipated to remain the same after construction of the proposed improvements. Core Requirement #5 – Construction Stormwater Pollution Prevention – A Construction Stormwater Pollution Prevention Plan (CSWPPP) will be prepared and include within the TIR at the time of the civil permit submittal which describes the 13 required elements. Further, an erosion control plan will be prepared and included as part of the engineering plan set. The contractor may need to amend and update these plans as part of development and/or management of the SWPPP. The contractor will be responsible for preparing the full SWPPP which shall comply with all of the required elements and the Washington Department of Ecology requirements for coverage under the NPDES Construction Stormwater General Permit. Core Requirement #6 – Maintenance and Operations – All stormwater facilities will be located on the parcel and privately owned. A site-specific Operations and Maintenance Manual will be completed and included herein as Appendix 6 at the time of the civil permit submittal. Core Requirement #7 – Financial Guarantees and Liability– If required, the Owner will post a drainage facilities restoration and site stabilization financial guarantee. Core Requirement #8 – Water Quality – According to the City of Federal Way Water Quality Applications Map (see Appendix 3), the project is located within an Enhanced Basic Water Quality Treatment Menu area. Per Section 1.2.8.1 of the KCSWDM, commercial land uses require the Enhanced Basic WQ menu. The proposed project will construct a hotel which is considered a commercial land use. Enhanced basic treatment will be provided for all of the target pollution-generating impervious surfaces by two Modular Wetland Systems. Core Requirement #9 – Flow Control BMPs – The proposed project is on a site that is greater than 22,000 square feet, but is not a Large Rural Lot as defined in Section 1.2.9.2.3 of the KCSWDM, therefore, according to Section 1.2.9.2.2 of the KCSWDM the Large Lot BMP Requirements must be applied to this project. Town Place Hotel 5 of 9 Technical Information Report Special Requirement #1 – Other Adopted Area-Specific Requirements – In addition to meeting the minimum requirements of the KCSWDM, this project will also comply with the 2017 City of Federal Way Addendum to the King County Surface Water Design Manual. Special Requirement #2 – Flood Hazard Area Delineation – The proposed project is not located in or adjacent to a flood hazard area. This Special Requirement is not applicable. Special Requirement #3 – Flood Protection Facilities – The proposed project does not rely on an existing flood protection facility. This Special Requirement is not applicable. Special Requirement #4 – Source Control – Water quality source controls will be installed in accordance with the King County Stormwater Pollution Prevention Manual. Special Requirement #5 – Oil Control – The expected average daily traffic (ADT) count will not be greater than 100 vehicles per 1,000 square feet of gross building area; oil control is not required. 3. OFFSITE ANALYSIS 3.1 LEVEL 1 DOWNSTREAM ANALYSIS Task 1. Study Area Definition and Maps The proposed project site does not appear to have any significant offsite run-on from the adjacent areas. Task 2. Resource Review According to the FEMA Flood Insurance Rate Map (FIRM) the project site is located within Zone X which is an area determined to be outside the 500-year floodplain. The project is not located within any basin plan areas or drainage and water quality problem areas. Task 3. Field Inspection There are no known flooding or conveyance problems located on or downstream from the project. The proposed project improvements will include the design of stormwater quality and quantity facilities and therefore it is anticipated at this time that the release flows from the project will remain the same or decrease. Task 4. Drainage System Description and Problem Descriptions Currently, stormwater runoff within the parcel sheet flows into the stream located on-site. It was observed that there are densely vegetated steep slopes down to the stream. These sloped vegetated areas are located within the 100’ stream buffer and will remain undisturbed throughout the life of the project. Task 5. Mitigation of Existing or Potential Problems At this time, there are no known drainage problems on-site or downstream from the parcel. The proposed project will not alter the drainage patterns or increase stormwater runoff from the parcel. Stormwater runoff will be released at the predeveloped forested condition to meet core requirement #3. A flow spreader will disperse the stormwater runoff on the outside of the stream buffer. Town Place Hotel 6 of 9 Technical Information Report 4. FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 EXISTING SITE HYDROLOGY (PART A) The subject site is +/- 2.80 acres in size. Topography within the property is generally flat throughout the site except for the side slopes of a stream that runs through the middle of the parcel. The site appears to have been cleared around 1990, with minimal to no on-site development. Today, the site remains undeveloped with trees and grassland. See the figures below. Figure 1: Existing Conditions (1990) Figure 2: Existing Conditions (2018) Currently, stormwater runoff within the project parcel sheet flows to the east and west and into the stream located near the center of the parcel. Although a portion of the site was cleared in the 90’s, the vegetation adjacent to the stream has remained and matured. There are no known flow control or water quality facilities located on-site. 4.2 DEVELOPED SITE HYDROLOGY (PART B) The proposed project follows the development requirements stated in the 2016 KCSWDM. Following Figure 1.1.2.A (See Appendix 2), this project classifies as a new development that requires a Full Drainage Review. The proposed project is not a single family residential or agricultural project and results in over 2,000 s.f. of new and/or replaced impervious surface. As part of the proposed project, stormwater runoff from the proposed improvements will be collected, treated, detained in an underground detention system and released at the predeveloped rates into a concrete flow spreader box. The stormwater system has been designed to meet Core Requirements #1-9 and Special Requirements #1-5. See Appendix 4 for the proposed stormwater facility locations and details. Table 1: Land Type Designations Existing vs. Proposed below illustrates the existing and proposed impervious and pervious areas of the disturbed areas (See Appendix 3 for the basin maps). Town Place Hotel 7 of 9 Technical Information Report LAND TYPE DESIGNATIONS AREA (ACRES) % OF TOTAL AREA Existing Areas 1.36 100 Impervious 0.00 0 Pervious 1.36 100 Proposed Areas 1.36 100 Roof 0.33 24.26 Asphalt 0.70 51.47 Sidewalk 0.09 6.62 Landscape 0.24 17.65 Table 1: Land Type Designations Existing vs. Proposed 4.3 PERFORMANCE STANDARDS (PART C) The proposed project is on a site that is greater than 22,000 square feet but is not a Large Rural Lot as defined in Section 1.2.9.2.3 of the KCSWDM, therefore, according to Section 1.2.9.2.2 of the KCSWDM the Large Lot BMP Requirements must be applied to this project. According to the City of Federal Way Water Quality Applications Map (see Appendix 3), the project is located within an Enhanced Basic Water Quality Treatment Menu area. Per Section 1.2.8.1 of the KCSWDM, commercial land uses require the Enhanced Basic WQ menu. The conveyance system on-site will be entirely made up of new components and therefore must meet the requirements stated in Section 1.2.4.1 of the KCSWDM. The new pipe systems have been designed with sufficient capacity to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas. 4.4 FLOW CONTROL SYSTEM (PART D) Flow control is required for the proposed development and will be provided through an underground detention system made up of Contech CMP pipes. The 2012 Western Washington Hydrology Model (WWHM) was used to size the flow control facilities so that they will meet Core Requirement #7. All of the stormwater runoff on-site will be collected, treated, and detained within the underground detention system. WWHM was used to size the detention system for the appropriate volume, and to provide the required release rates of the system. The required detention volume of the system is 26,650 c.f. The proposed system will consist of 60” Perforated CMP pipe so that the outer rock can be used as storage as well. The control structure will be constructed with three orifices, a 0.66” diameter orifice at the bottom of the facility, a 1” diameter orifice 3 feet from the bottom of the facility, and a 1.5” diameter orifice 4.7 feet from the bottom of the facility. The drainage plan with the detention and conveyance layouts has been included as Appendix 4. See Appendix 9 for the WWHM report. 4.5 WATER QUALITY SYSTEM (PART E) Enhanced treatment will be provided for the proposed development through Modular Wetland Systems. The Modular Wetland Systems will precede the detention system and therefore are required to treat the flow rate at or below which 91% of the runoff volume, as estimated by WWHM. At this stage in design, it is assumed that the stormwater runoff from the sidewalk areas will flow across the asphalt parking areas, and therefore were included in the treatment facility sizing. The Modular Wetland Systems are equipped with an internal bypass and therefore can be sized using the off-line water quality flow rates. See below for the treatment facility sizes. See Appendix 3 Town Place Hotel 8 of 9 Technical Information Report for the Treatment Basin Map exhibit. The drainage plan with the locations of the treatment facilities has been included as Appendix 4. See Appendix 9 for the WWHM reports. TOTAL AREA (ACRES) IMPERVIOUS AREA (ACRES) PERVIOUS AREA (ACRES) WATER QUALITY FLOW RATE (CFS) TREATMENT SYSTEM SIZE Basin 1 0.35 0.29 0.06 0.0262 4x4 Basin 2 0.54 0.47 0.07 0.0427 4x4 Table 2: Treatment Basin Summary 5. CONVEYANCE SYSTEM ANALYSIS AND DESIGN All stormwater conveyance systems will be sized to convey the 24-hour 25-year storm within the pipe. All proposed stormwater pipes are a minimum of 12” at a minimum slope of 0.50%. A full backwater and flow capacity analysis will be completed and provided in this report at the time of the civil permit submittal. 6. SPECIAL REPORTS AND STUDIES On-Site Soils Information A geotechnical investigation was conducted by GeoResources in January 2008. Four test pits were conducted to depths of approximately 10 feet. The subsurface conditions encountered in the test pits were fairly uniform. The soils they observed in the test pits generally consist of 6 inches of topsoil overlying old fill and silty sand with gravel consistent with glacial till. In test pits TP-1, TP-3, and TP-4, they encountered loose to medium dense, moist fill consisting of silty sand with gravel and occasional topsoil and construction debris to depths ranging from 1 to 7.5 feet below surface grades. Groundwater seepage was not encountered in any of the excavated test pits. Infiltration testing was not conducted at this time. See Appendix 5 for the geotechnical reports. See Appendix 5 for the existing conditions report that includes the stream and critical areas study. No other special reports or studies were required for this project. 7. OTHER PERMITS Utility, paving, building, and grading permits may need to be secured prior to beginning construction activities. Coverage under Washington State Department of Ecology Phase II National Pollutant Discharge Elimination System Stormwater Permit will also need to be secured prior to beginning construction activities. 8. CSWPP PLAN ANALYSIS AND DESIGN 8.1 ESC PLAN ANALYSIS AND DESIGN (PART A) A SWPPP will be prepared and attached herein as Appendix 7 at the time of the civil permit submittal. Town Place Hotel 9 of 9 Technical Information Report 8.2 SWPPS PLAN DESIGN (PART B) A SWPPP will be prepared and attached herein as Appendix 7 at the time of the civil permit submittal. 9. BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Bond Quantities Worksheet, facility summaries, and declaration of covenant(s) for privately maintained flow control facilities will be completed and enclosed herein as Appendix 10 at the time of the civil permit submittal. 10. OPERATIONS AND MAINTENANCE MANUAL The owner of the Town Place Hotel will be responsible in maintaining all stormwater facilities on-site. An operation and maintenance manual will be provided at the time of the civil permit submittal as Appendix 6. END OF TECHNICAL INFORMATION REPORT APPENDIX 1 SITE VICINITY MAP 8730 Tallon Lane NE, Suite 200  Lacey, WA 98516  Office 360.352.1465  Fax 360.352.1509  scjalliance.com PROJECT LOCATION PROJECT LOCATION APPENDIX 2 DETERMINATION OF MINIMUM REQUIREMENTS WORKSHEET 1.1.2 DRAINAGE REVIEW TYPES AND REQUIREMENTS 2009 Surface Water Design Manual 1/9/2009 1-11 FIGURE 1.1.2.A FLOW CHART FOR DETERMINING TYPE OF DRAINAGE REVIEW REQUIRED Is the project a single family residential or agricultural project that results in ≥2,000 sf of new and/or replaced impervious surface or ≥7,000 sf of land disturbing activity, AND meets one of the following criteria? • The project results in ≤10,000 sf of total impervious surface added since 1/8/01, ≤5,000 sf of new imperv surface, and ≤35,000 sf of new pervious surface (for RA, F, or A sites, new pervious surface is ≤52,500 sf or remainder of site if ≥65% is preserved in native vegetation), OR • The project results in ≤10,000 sf of total impervious surface added since 1/8/01 and new pervious surface is ≤35,000 – 3.25 x new impervious surface (for sites ≥22,000 sf, use 2.25, and for RA, F, or A sites, increase by 50% or use remainder of site if ≥65% is preserved in native vegetation), OR • The project results in ≤4% total imperv surface and ≤15% new pervious surface on a single parcel site zoned RA or F, or a single/multiple parcel site zoned A, and all impervious area on the site, except 10,000 sf of it, will be set back from natural location of site discharge at least 100 ft per 10,000 sf of total impervious surface? Yes SMALL PROJECT DRAINAGE REVIEW Section 1.1.2.1 Note: The project may also be subject to Targeted Drainage Review as determined below. No Does the project result in ≥2,000 sf of new and/or replaced impervious surface or ≥7,000 sf of new pervious surface, OR is the project a redevelopment project on a parcel or combination of parcels in which new plus replaced impervious surface totals ≥5,000 sf and whose valuation of proposed improvements (excluding required mitigation and frontage improvements) is >50% of the assessed value of existing improvements? No Does the project have the characteristics of one or more of the following categories of projects (see more detailed threshold language on p. 1-15)? 1. Projects containing or adjacent to a flood, erosion, or steep slope hazard area; projects within a Critical Drainage Area or Landslide Hazard Drainage Area; or projects that propose ≥7,000 sf (1 ac if project is in Small Project Drainage Review) of land disturbing activity. 2. Projects proposing to construct or modify a drainage pipe/ditch that is 12" or larger or receives runoff from a 12" or larger drainage pipe/ditch. 3. Redevelopment projects proposing ≥$100,000 in improvements to an existing high-use site. Yes No Yes Reassess whether drainage review is required per Section 1.1.1 (p. 1-9). TARGETED DRAINAGE REVIEW Section 1.1.2.2 Is the project an Urban Planned Development (UPD), OR does it result in ≥50 acres of new impervious surface within a subbasin or multiple subbasins that are hydraulically connected, OR does it have a project site ≥50 acres within a critical aquifer recharge area? No FULL DRAINAGE REVIEW Section 1.1.2.3 Yes LARGE PROJECT DRAINAGE REVIEW Section 1.1.2.4 APPENDIX 3 BASIN MAP EXHIBITS JOB No.:DRAWING FILE No.:DATE:HORIZONTAL SCALE:EXHIBIT No:SHEET No:8730 TALLON LANE NE, SUITE 200, LACEY, WA 98516P: 360.352.1465 F: 360.352.1509SCJALLIANCE.COM1"=20'SEPTEMBER, 20193278.013278.01 Ex. Basin Map.dwgEXISTING CONDITIONS MAPTOWN PLACE HOTEL, FEDERAL WAYEX-011SCALE IN FEET02040EXISTING BASIN AREAS:IMPERVIOUS AREA:0.00 ACRESPERVIOUS AREA:1.36 ACRESTOTAL:1.36 ACRES 90 UNIT - 4-STORY HOTELJOB No.:DRAWING FILE No.:DATE:HORIZONTAL SCALE:EXHIBIT No:SHEET No:8730 TALLON LANE NE, SUITE 200, LACEY, WA 98516P: 360.352.1465 F: 360.352.1509SCJALLIANCE.COM1"=20'SEPTEMBER, 20193278.013278.01 Pr. Basin Map.dwgPROPOSED CONDITIONS MAPTOWN PLACE HOTEL, FEDERAL WAYEX-022SCALE IN FEET02040PROPOSED BASIN AREAS:ROOF AREA:0.33 ACRESCONCRETE AREA:0.09 ACRESASPHALT AREA:0.70 ACRESPERVIOUS AREA:0.24 ACRESTOTAL:1.36 ACRES 90 UNIT - 4-STORY HOTELJOB No.:DRAWING FILE No.:DATE:HORIZONTAL SCALE:EXHIBIT No:SHEET No:8730 TALLON LANE NE, SUITE 200, LACEY, WA 98516P: 360.352.1465 F: 360.352.1509SCJALLIANCE.COM1"=20'SEPTEMBER, 20193278.013278.01 Tr. Basin Map.dwgTREATMENT BASIN MAPTOWN PLACE HOTEL, FEDERAL WAYEX-033SCALE IN FEET02040TREATMENT BASIN AREAS:BASIN 1:0.35 ACRESIMPERVIOUS AREA:0.29 ACRESPERVIOUS AREA:0.06 ACRESBASIN 2:0.54 ACRESIMPERVIOUS AREA:0.47 ACRESPERVIOUS AREA:0.07 ACRES Fife Milton Tacoma DesMoines Edgewood Pacific AuburnFederalWay Kent Hyl e b o s C r e e k W a t e r w a y Bla i r W a t e r w a y P uyallu p R i v erPuget Sound BayDumas PovertyBay Sit c u m W a t e r w a y CommencementBay LakeSteel Star Lake MirrorLake GenevaLake North Lake Lorene Lake JeaneLake EasterLake Dolloff LakeTroutLake FiveMileLakeLake KillarneyHOYT RD SW MILITARY RD SWEST VALLEY HWYS 288th ST DASH POINT R D DASH PT RDMILITARY RD S21st AVE SWPACIFIC HWYMARINE VIEW DRSW 336th ST NORTHSHORE PK W Y INTERSTATE 5E 11th STHWY 18H W Y 18PACIFIC HWY S28TH AVE SENC HAN T ED P KW Y 51st AVE SINTERSTATE 51st AVE SPACIFIC HWY SS 320th ST 21st AVE SWS 336th ST1st AVE SS 312th ST SW 320th ST SW 356th ST S 348th ST SR 99S 272nd ST 33rd ST NE Lower PugetSound Basin HylebosCreekBasin MillCreekBasin LowerGreenRiverBasin 0 0.5 10.25 Mile This map is intended for use as a graphical representation only. The City of Federal Way makes no warranty as to its accuracy. Legend Drainage Basin Boundary Streams City Limits Lakes and Wetlands Scale: City of Federal Way Flow ControlApplications Map Map Date: February, 2010SWM DivisionCity of Federal Way33325 8th Ave SPO Box 9718Federal Way, WA 98063(253) 835-2700www.cityoffederalway.com R:\erike\swm\FlowControl\flowcontrol.mxd Flow Control Basic Flow Control Areas Conservation Flow Control Areas Flood Problem Flow Control Areas Major Receiving Waters1. Puget Sound PROJECT LOCATION !!7Ái Hyl e b o s C r e e k W a t e r w a y Bla i r W a t e r w a y P uyallu p R i v erPuget Sound BayDumas PovertyBay Sit c u m W a t e r w a y CommencementBay HOYT RD SW MILITARY RD SWEST VALLEY HWYMILTON WAY S 288th ST DASH POINT R D DASH PT RDMILITARY RD S21st AVE SWPACIFIC HWYMARINE VIEW DRSW 336th ST NORTHSHORE PK W Y INTERSTATE 5E 11th STHWY 18H W Y 18PACIFIC HWY S28TH AVE SENC HAN T ED P KW Y 51st AVE SINTERSTATE 51st AVE SPACIFIC HWY SS 320th ST 21st AVE SWS 336th ST1st AVE SS 312th ST SW 320th ST SW 356th ST S 348th ST SR 99S 272nd ST 33rd ST NE Fife Milton Tacoma DesMoines Edgewood Pacific Auburn Algona FederalWay Kent Lower PugetSound Basin HylebosCreekBasin LowerGreenRiverBasin 126286.04851 ft MillCreekBasin City ofFederal Way Water QualityApplicationsMap This map is intended for use as a graphical representation only. The City of Federal Way makes no warranty as to its accuracy. Map Date: November 2013SWM DivisionCity of Federal Way33325 8th Ave S.Federal Way, WA. 98003(253) 835 - 2700www.cityoffederalway.com \\users\erike\swm\watqual.mxd * High density single family, multi-family, commercial, and industrial uses, as well as most roads, are subject to Enhanced Basic Water Quality Treatment Requirements. Legend Drainage Basin Boundary Streams City Limits 0 0.5 10.25 Mile´ Enhanced Basic Water QualityTreatment Menu Required* Sensitive Lake !!7Ái Identified Sphagnum Bog Wetlands Water Quality Treatment Area Types Scale: PROJECT LOCATION APPENDIX 4 PRELIMINARY CONSTRUCTION PLANS APPENDIX 5 SPECIAL REPORTS EXISTING CONDITIONS REPORT HOTEL CONCEPTS FEDERAL WAY, WASHINGTON Prepared For: HOTEL CONCEPTS Seattle, Washington Prepared By: TALASAEA CONSULTANTS, INC. Woodinville, Washington April 2018 Existing Conditions Report Hotel Concepts Federal Way, Washington Prepared For: Alfred Kim Hotel Concepts 3926 Aurora Avenue North Seattle, Washington 98103 Prepared By: Talasaea Consultants, Inc. 150250 Bear Creek Road NE Woodinville, Washington 98077 (425) 861-7550 April 2018 Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page i EXECUTIVE SUMMARY PROJECT NAME: Hotel Concepts Site PROJECT LOCATION: The address for the Site is 34839 Pacific Highway South in the City of Federal Way, Washington. The project includes King County Tax Parcel number 202104-9044. The Public Land Survey System location of the Site is Section 20, Township 21 North, Range 4 East, Willamette Meridian. CLIENT: Alfred Kim, Hotel Concepts PROJECT STAFF: Bill Shiels, Principal; Jennifer Marriott, Senior Ecologist; and Kristen Numata, Ecologist. FIELD SURVEY: Site evaluations were performed on 1 and 6 February 2018. DETERMINATION: One stream (a tributary to West Hylebos Creek) was identified on-site, and one wetland (Wetland A) was observed off-site to the north. West Hylebos Creek is classified as a Type F stream, which requires a 100-foot setback per Federal Way Revised Code (FWRC). Wetland A rated as a Category III with a habitat score of 5, which requires a 105-foot standard buffer. VEGETATION: The Site is undeveloped, and is dominated by invasive species from lack of maintenance. The majority of the stream buffer is forested with deciduous tree species such as red alder and black cottonwood. PREVIOUS MITIGATION: As part of a previously permitted development, a 72” culvert on the north side of the property was removed and the 100-foot buffer for West Hylebos Creek was enhanced. Native species identified to be planted within the mitigation area included Douglas fir, western red cedar, willows, pacific ninebark, and snowberry. Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page ii TABLE OF CONTENTS Executive Summary ......................................................................................................... i Table of Contents .............................................................................................................ii List of Figures and Appendices ....................................................................................... iii Chapter 1. Introduction ................................................................................................ 1 1.1 Purpose of Report ............................................................................... 1 1.2 Statement of Accuracy ........................................................................ 1 1.3 Qualifications ....................................................................................... 1 Chapter 2. Property Description .................................................................................. 2 2.1 Property Location ................................................................................ 2 2.2 Existing Site Development ................................................................... 2 Chapter 3. Methodology .............................................................................................. 2 3.1 Background Data Reviewed ................................................................ 2 3.2 Field Investigation ............................................................................... 3 3.2.1 Wetland Determinations ...................................................................... 3 3.2.2 Ordinary High Water Mark Determinations .......................................... 3 Chapter 4. Results ....................................................................................................... 3 4.1 Analysis of Existing Information ........................................................... 4 4.1.1 Natural Resources Conservation Service ............................................ 4 4.1.2 National Wetlands Inventory ................................................................ 4 4.1.3 King County GIS Database ................................................................. 4 4.1.4 City of Federal Way Public Records Request ...................................... 4 4.2 Analysis of Existing Conditions ............................................................ 4 4.2.1 Streams ............................................................................................... 4 4.2.2 Wetlands ............................................................................................. 5 4.2.3 Other Features .................................................................................... 5 Chapter 5. Regulatory Review ..................................................................................... 5 5.1 City of Federal Way Zoning Code ....................................................... 5 Chapter 6. Summary ................................................................................................... 6 Chapter 7. References ................................................................................................ 7 Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page iii LIST OF FIGURES Figure 1 – Vicinity Map and Driving Directions Figure 2 – NRCS Soils Map Figure 3 – National Wetlands Inventory Map Figure 4 – Existing Conditions Map Figures occur at the end of the report. APPENDICES Appendix A: Documentation of Permanent Easement, dated 3 November 2009 Appendix B: Raedeke Associates Wetland & Stream Assessment, dated 30 January 2008 Appendix C: 2009 Site Development Plans, prepared by TRT Engineering, Inc. Appendix D: Wetland Rating Form, Washington State Department of Ecology Wetland Rating System for Western Washington (2014), Talasaea Consultants, 2018 Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 1 CHAPTER 1. INTRODUCTION 1.1 Purpose of Report This report is the result of an existing conditions study for the property located at 34839 Pacific Highway South in Federal Way, Washington (referred to hereinafter as the “Site”) (Figure 1). This report has been prepared to comply with the requirements of Federal Way Revised Code (FWRC) Chapter 19.145.080 – Critical area report to summarize the existing conditions of the Site. No site development impacts or mitigation are included within this report. This report will provide and describe the following information: • General property description; • Methodology for critical areas investigation; • Results of critical areas background review and field investigation; • Existing site conditions; and • Regulatory review. 1.2 Statement of Accuracy Stream and wetland characterizations and ratings were conducted by trained professionals at Talasaea Consultants, Inc., and adhered to the protocols, guidelines, and generally accepted industry standards available at the time the work was performed. The conclusions in this report are based on the results of analyses performed by Talasaea Consultants and represent our best professional judgment. To that extent and within the limitation of project scope and budget, we believe the information provided herein is accurate and true to the best of our knowledge. Talasaea does not warrant any assumptions or conclusions not expressly made in this report, or based on information or analyses other than what is included herein. 1.3 Qualifications Field investigations and evaluations were conducted by Bill Shiels, Principal; Jennifer Marriott, PWS, Senior Ecologist; and Kristen Numata, Ecologist. Bill Shiels has a Bachelor’s Degree in Biology from Central Washington University and a Master’s Degree in Biological Oceanography from the University of Alaska. He has over 40 years of experience in wetland delineations and mitigations. Jennifer Marriott has a Bachelor’s Degree and a Master’s Degree in Biology from University of Central Florida, and a second Master’s Degree in Soil and Environmental Science from the University of Florida. She has over 13 years of experience in wetland delineations and environmental permitting. Kristen Numata has a Bachelor’s Degree in Biology and Environmental Science from Santa Clara University. Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 2 CHAPTER 2. PROPERTY DESCRIPTION 2.1 Property Location The property is located along Pacific Highway (SR-99), and includes King County Tax Parcel number 202104-9044. The Site is approximately 2.8 acres in size. The Public Land Survey System location of the Site is Section 20, Township 21 North, Range 4 East, Willamette Meridian. The topography of the Site is sloping downhill from east to west. The Site is bound by Pacific Highway to the east, development to the north and immediately west, and West Hylebos Wetlands Park farther to the west. The parcels to the south are not developed. 2.2 Existing Site Development The Site is not currently developed, although there have been previously submitted plans to develop the property. Several informal pedestrian trails traverse the Site that appear regularly used, and evidence of homeless camps occur across the Site. The majority of the Site is dominated by a variety of grasses and Scot’s broom (Cytisus scoparius) except for a shrub- and young tree-dominated buffer around the stream. CHAPTER 3. METHODOLOGY The critical areas analysis of the Site involved a two-part effort. The first part consisted of a preliminary assessment of the Site and the immediate surrounding area using published environmental information. This information includes: 1) Wetland and soils information from resource agencies; 2) Critical Areas information from King County and the City of Federal Way; 3) Orthophotography and LIDAR imagery; and, 4) Relevant studies completed or ongoing near the Site. The second part consisted of site investigations where direct observations and measurements of existing environmental conditions were made. Observations included plant communities, soils, hydrology, and stream conditions. This information was used to help characterize the site and define the limits of critical areas onsite and offsite for regulatory purposes (see Section 3.2 – Field Investigation below). 3.1 Background Data Reviewed Background information from the following sources was reviewed prior to field investigations: • US Fish and Wildlife Service (USFWS), Wetlands Online Mapper (National Wetlands Inventory) (U.S. Fish and Wildlife Service, 2018) (www.wetlandsfws.er.usgs.gov/wtlnds/launch.html); • Natural Resources Conservation Service, Web Soil Survey (Natural Resources Conservation Service, 2018)(www.websoilsurvey.nrcs.usda.gov/app/); • King County GIS Database (King County, 2018); • Washington Department of Fish and Wildlife Priority Habitat and Species (PHS) Mapper; Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 3 • Orthophotography from USDA’s National Agricultural Imagery Program (NAIP 2018), Earth Explorer (USGS), and Google Earth; and • Information obtained from the City of Federal Way via Public Records Requests (2018). 3.2 Field Investigation Talasaea Consultants evaluated the Site on 1 and 6 February 2018. 3.2.1 Wetland Determinations Site investigation utilized the routine approach described in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountain, Valleys, and Coast Regions (U.S. Army Corps of Engineers, 2010) to evaluate the Site for potential wetlands. Plant species were identified according to the taxonomy of Hitchcock and Cronquist (Hitchcock, et al. 1973). Taxonomic names were updated and plant wetland status was assigned according to North American Digital Flora: National Wetland Plant List, Version 2.4.0 (Lichvar, et al. 2016). Wetland classes were determined with the U.S. Fish and Wildlife Service’s system of wetland classification (Cowardin, et al. 1979). Vegetation was considered hydrophytic if greater than 50% of the dominant plant species had a wetland indicator status of facultative or wetter (i.e., facultative, facultative wetland, or obligate wetland). Wetland hydrology was determined based on the presence of hydrologic indicators listed in the Corps’ Regional Supplement. These indicators are separated into Primary Indicators and Secondary Indicators. To confirm the presence of wetland hydrology, one Primary Indicator or two Secondary Indicators must be demonstrated. Indicators of wetland hydrology may include, but are not necessarily limited to: drainage patterns, drift lines, sediment deposition, watermarks, stream gauge data and flood predictions, historical records, visual observation of saturated soils, and visual observation of inundation. Soils on the site were considered hydric if one or more of the hydric soil indicators listed in the Corps’ Regional Supplement were present. Indicators include presence of organic soils, reduced, depleted, or gleyed soils, or redoximorphic features in association with reduced soils. 3.2.2 Ordinary High Water Mark Determinations The ordinary high water mark was determined using the current methodology as described in Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State” (Anderson, et al. 2016). CHAPTER 4. RESULTS This section describes the results of our in-house research and field investigations. For the purpose of this report, the term “vicinity” describes an area within 300 feet of the Site. Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 4 4.1 Analysis of Existing Information The following sources provided information on site conditions based on data compiled from resource agencies and local government. 4.1.1 Natural Resources Conservation Service The NRCS maps two soil types on the Site: Norma sandy loam and Everett-Alderwood gravelly sandy loam, 6-15% slopes (Figure 2). 4.1.2 National Wetlands Inven tory The National Wetlands Inventory (NWI) maps one wetland on-site and one wetland off- site to the north (Figure 3). The mapped on-site wetland is a Palustrine Scrub-Shrub, seasonally flooded (PSSC) wetland. The wetland mapped north of the Site is mapped as a Palustrine Forested, seasonally flooded (PFOC) wetland. A large wetland complex is mapped south and west of the Site that overlaps the West Hylebos Wetland Park, which is mapped as a Palustrine Forested, temporarily flooded (PFOA) wetland with pockets of mapped PSSC wetlands. No streams are mapped on the Site by the NWI. 4.1.3 King County GIS Database King County identifies one stream that bisects the site. No wetlands were identified on, or in the vicinity of, the Site. 4.1.4 City of Federal Way Public Records Request The stream bisecting the Site is labeled as West Hylebos Creek. However, other sources identify the on-site stream as a tributary to West Hylebos Creek and not the main stem of this stream. According to documents acquired from the City of Federal Way, a permanent easement for surface water facilities (approximately 51,998 sf) is located in the western half of the property. The easement is associated with the on-site stream and includes the 100-foot standard buffer associated with the stream. Effectively, the Site from the eastern limits of the 100-foot stream buffer to the western property boundary are contained within the above-referenced easement (Appendix A). 4.2 Analysis of Existing Conditions The Site is generally heavily disturbed and is dominated by a variety of grasses, Scot’s broom, and Himalayan blackberry. There is an abundance of debris on the Site from homeless activity. 4.2.1 Streams One stream (likely a tributary to West Hylebos Creek) was identified within the western half of the property (Figure 4). The stream enters the Site from the north and continues off property to the south before co-mingling with Hylebos Creek to the southwest. Short, steep slopes are located on either side of the stream channel as this stretch of the stream is highly channelized. The streambed was a mix of round rocks and silt. Riffles and pool complexes were observed off-site to the south, though none occurred within the Site. As outlined in the Raedeke Associates Wetland & Stream Assessment, dated 30 January 2008, a large 72” culvert was removed from the north end of the property as Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 5 part of the previously permitted project (Appendix B). The 100-foot stream buffer was enhanced with native species such as Douglas fir (Pseudotsuga menziesii), western red cedar (Thuja plicata), willows (Salix sp.), pacific ninebark (Physocarpus capitatus), and snowberry (Symphoricarpos albus). While the development associated with this mitigation was never completed, portions of the development plan were completed, including the stream mitigation and the construction of temporary stormwater facilities that were then left in place. 4.2.2 Wetlands One wetland (Wetland A) was observed off-site to the north. Wetland A is dominated by black cottonwood (Populus balsamifera), red alder (Alnus rubra), and salmonberry (Rubus spectabilis). Hydrology for Wetland A is provided by precipitation, interception of surface and groundwater, and overbank flooding from the stream. Soils were not evaluated within Wetland A because this feature occurs off-site. Wetland A appears to be limited to a small area in proximity to the stream that is a combination of riverine and depressional wetland. Conditions were evaluated immediately adjacent to the Site in more detail to determine whether the buffer for Wetland A would extend onto the Site. The current extent of Wetland A was estimated based on field observations and aerial imagery. Wetland A is much smaller under current conditions than it was during the last round of critical area assessments done by Raedeke in 2008, which we believe to be a result of the culvert removal done as part of the previously permitted mitigation activities. While it seems difficult to think a 72” culvert caused a backwater effect, field conditions reflect an area that previously held higher levels of water than what was currently observed. The culvert removal is the most obvious detail that has changed since 2008. Water is able to move freely though the stream channel without any blockages and hindrances. The Stream is down-cut through the Site and the immediate areas north of the Site, such that stream-driven hydrology has little opportunity to extend up the slope. 4.2.3 Other Features Two man-made features occur east of the stream, and are presumed to have been constructed to handle stormwater, though no outlets were found associated with either feature. Both are clearly constructed features with steep, defined side slopes that are currently vegetated. The eastern feature, located immediately outside of the stream buffer, coincides with the proposed temporary sediment pond that was identified on the previously-permitted plans (Appendix C). The western feature, located immediately within the stream buffer from the temporary sediment pond, is square in shape and of an unknown origin. It appears to have been constructed around the same time as the temporary sediment trap/pond, but is not reflected on any of the permitted drawings found to date. These features do not meet the definition of a regulated wetland. CHAPTER 5. REGULATORY REVIEW 5.1 City of Federal Way Zoning Code Wetlands and other critical areas in Federal Way are regulated under the Federal Way Revised Code (FWRC) 19.145. Wetlands have been rated using the Washington State Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 6 Wetland Rating System for Western Washington (Ecology Publication # 14-06-029). Wetland rating datasheets are provided in Appendix D. Due to its connection to Hylebos Creek, the on-site stream is considered a Type F stream. Fish-bearing streams within Federal Way have a standard 100-foot buffer according to FWRC 19.14.270. Wetland A was preliminarily rated as a Category III wetland with a Habitat Score of 5 based on best professional judgment, and a combination of limited field and extensive office evaluations. Category III wetlands with a Habitat Score of 5 require a 105-foot standard buffer according to FWRC 19.145.420. The large wetland complex to the southwest was not identified or verified in the field. Assuming the NWI-identified boundary is close to the actual wetland boundary, the approximate edge of this wetland is more than 150-feet from the edge of the Site, and more than 400 feet from the eastern edge of the on-site stream buffer. Therefore, this off-site wetland, assuming the largest wetland buffers, would not extend a buffer onto the Site that would extend beyond the existing on-site critical areas. Therefore, no additional fieldwork was conducted to attempt to rate this large wetland complex. CHAPTER 6. SUMMARY The Site is an approximately 2.8 acre parcel located in Federal Way, Washington. One stream (either the main stem of West Hylebos Creek or a tributary to West Hylebos Creek) and one wetland (Wetland A) were identified on, or in the vicinity of, the Site. The standard buffer for a fish-bearing stream is 100 feet. The stream continues off-site and connects to Hylebos Creek downstream approximately 2,500 feet from the Site. Category III wetlands with a Habitat Score of 5 require a 105-foot standard buffer, which does not extend a buffer for Wetland A onto the Site. A permanent easement exists on the Site that includes the lands from the eastern limits of the 100-foot stream buffer to the western property boundary. No additional critical areas constraints exist on this property beyond those already documented with the City of Federal Way. Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 7 CHAPTER 7. REFERENCES Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service, Department of the Interior. FWSOBS-70/31. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss. Federal Way Revised Code. Chapter 19.145 Environmentally Critical Areas (FWRC, 2017). Hitchcock, C.L., and A. Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. 730 pp. Hruby, T. 2014. Washington State Wetland Rating System for Western Washington. 2014 Update. Washington State Department of Ecology Publication # 14-06-029. Lichvar, R.W., D.L. Banks, W.N. Kirchner, and N.C. Melvin. 2016. The National Wetland Plant List: 2016 wetland ratings. Phytoneuron 2016-30: 1-17. Published 28 April 2016. ISSN 2153 733X Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/. Accessed [2018]. U.S. Army Corps of Engineers. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region. Wetland Regulatory Assistance Program. ERDC/EL TR-10-3 U.S. Fish and Wildlife Service. 1989. National Wetlands Inventory Map, Poverty Bay Quadrangle. Washington State Department of Ecology. March 1997. Washington State Wetland Identification and Delineation Manual. Washington State Department of Ecology. Water Quality Assessment and 303(d) List. 2016. www.ecy.wa.gov/programs/wq/303d (accessed 2018). Washington State Department of Fish and Wildlife [Map Online], Olympia (WA): SalmonScape [2018]. URL: <http//wdfw.wa.gov/mapping/salmonscape/index.html> Washington State Department of Fish and Wildlife. 2016. Priority Habitats and Species Database [online], Olympia, WA. [Accessed 2018]. <www.wdfw.wa.gov/mapping/phs/> Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Page 8 FIGURES Figure 1 – Vicinity Map and Driving Directions Figure 2 – NRCS Soils Map Figure 3 – National Wetlands Inventory Map Figure 4 – Existing Conditions Map Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Appendix A APPENDIX A DOCUMENTATION OF PERMANENT EASEMENT, DATED 3 NOVEMBER 2009 Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Appendix B APPENDIX B RAEDEKE ASSOCIATES WETLAND & STREAM ASSESSMENT, DATED 30 JANUARY 2008 Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Appendix C APPENDIX C 2009 SITE DEVELOPMENT PLANS, PREPARED BY TRT ENGINEERING, INC. Hotel Concepts Existing Conditions Report April 2018 Copyright © 2018 Talasaea Consultants, Inc. 1719 Existing Conditions Report.docx Appendix D APPENDIX D WETLAND RATING FORM, WASHINGTON STATE DEPARTMENT OF ECOLOGY WETLAND RATING SYSTEM FOR WESTERN WASHINGTON (2014), TALASAEA CONSULTANTS, 2018 APPENDIX 6 OPERATIONS AND MAINTENANCE MANUAL (NOT INCLUDED AT THIS TIME) APPENDIX 7 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (NOT INCLUDED AT THIS TIME) APPENDIX 8 FEMA FLOOD INSURANCE MAP PROJECT LOCATION APPENDIX 9 DESIGN CALCULATIONS AND COMPUTATIONS WWHM2012 PROJECT REPORT DETENTION DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 2 General Model Information Project Name:3278.01 Town Place Hotel Detention Site Name: Site Address: City: Report Date:9/13/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/10/10 Version:4.2.16 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.36 Pervious Total 1.36 Impervious Land Use acre Impervious Total 0 Basin Total 1.36 Element Flows To: Surface Interflow Groundwater DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.24 Pervious Total 0.24 Impervious Land Use acre ROOF TOPS FLAT 0.33 SIDEWALKS FLAT 0.09 PARKING FLAT 0.7 Impervious Total 1.12 Basin Total 1.36 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 6 Mitigated Routing Vault 1 Width:57 ft. Length:85 ft. Depth:6.5 ft. Discharge Structure Riser Height:5.5 ft. Riser Diameter:18 in. Orifice 1 Diameter:0.66 in.Elevation:0 ft. Orifice 2 Diameter:1 in.Elevation:3 ft. Orifice 3 Diameter:1.5 in.Elevation:4.7 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.111 0.000 0.000 0.000 0.0722 0.111 0.008 0.003 0.000 0.1444 0.111 0.016 0.004 0.000 0.2167 0.111 0.024 0.005 0.000 0.2889 0.111 0.032 0.006 0.000 0.3611 0.111 0.040 0.007 0.000 0.4333 0.111 0.048 0.007 0.000 0.5056 0.111 0.056 0.008 0.000 0.5778 0.111 0.064 0.009 0.000 0.6500 0.111 0.072 0.009 0.000 0.7222 0.111 0.080 0.010 0.000 0.7944 0.111 0.088 0.010 0.000 0.8667 0.111 0.096 0.011 0.000 0.9389 0.111 0.104 0.011 0.000 1.0111 0.111 0.112 0.011 0.000 1.0833 0.111 0.120 0.012 0.000 1.1556 0.111 0.128 0.012 0.000 1.2278 0.111 0.136 0.013 0.000 1.3000 0.111 0.144 0.013 0.000 1.3722 0.111 0.152 0.013 0.000 1.4444 0.111 0.160 0.014 0.000 1.5167 0.111 0.168 0.014 0.000 1.5889 0.111 0.176 0.014 0.000 1.6611 0.111 0.184 0.015 0.000 1.7333 0.111 0.192 0.015 0.000 1.8056 0.111 0.200 0.015 0.000 1.8778 0.111 0.208 0.016 0.000 1.9500 0.111 0.216 0.016 0.000 2.0222 0.111 0.224 0.016 0.000 2.0944 0.111 0.233 0.017 0.000 2.1667 0.111 0.241 0.017 0.000 2.2389 0.111 0.249 0.017 0.000 2.3111 0.111 0.257 0.018 0.000 2.3833 0.111 0.265 0.018 0.000 2.4556 0.111 0.273 0.018 0.000 2.5278 0.111 0.281 0.018 0.000 2.6000 0.111 0.289 0.019 0.000 2.6722 0.111 0.297 0.019 0.000 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 7 2.7444 0.111 0.305 0.019 0.000 2.8167 0.111 0.313 0.019 0.000 2.8889 0.111 0.321 0.020 0.000 2.9611 0.111 0.329 0.020 0.000 3.0333 0.111 0.337 0.025 0.000 3.1056 0.111 0.345 0.029 0.000 3.1778 0.111 0.353 0.032 0.000 3.2500 0.111 0.361 0.034 0.000 3.3222 0.111 0.369 0.036 0.000 3.3944 0.111 0.377 0.038 0.000 3.4667 0.111 0.385 0.040 0.000 3.5389 0.111 0.393 0.042 0.000 3.6111 0.111 0.401 0.043 0.000 3.6833 0.111 0.409 0.045 0.000 3.7556 0.111 0.417 0.046 0.000 3.8278 0.111 0.425 0.047 0.000 3.9000 0.111 0.433 0.049 0.000 3.9722 0.111 0.441 0.050 0.000 4.0444 0.111 0.449 0.051 0.000 4.1167 0.111 0.457 0.052 0.000 4.1889 0.111 0.465 0.053 0.000 4.2611 0.111 0.473 0.054 0.000 4.3333 0.111 0.482 0.055 0.000 4.4056 0.111 0.490 0.057 0.000 4.4778 0.111 0.498 0.058 0.000 4.5500 0.111 0.506 0.059 0.000 4.6222 0.111 0.514 0.060 0.000 4.6944 0.111 0.522 0.060 0.000 4.7667 0.111 0.530 0.077 0.000 4.8389 0.111 0.538 0.085 0.000 4.9111 0.111 0.546 0.091 0.000 4.9833 0.111 0.554 0.097 0.000 5.0556 0.111 0.562 0.101 0.000 5.1278 0.111 0.570 0.106 0.000 5.2000 0.111 0.578 0.110 0.000 5.2722 0.111 0.586 0.114 0.000 5.3444 0.111 0.594 0.117 0.000 5.4167 0.111 0.602 0.121 0.000 5.4889 0.111 0.610 0.124 0.000 5.5611 0.111 0.618 0.368 0.000 5.6333 0.111 0.626 0.902 0.000 5.7056 0.111 0.634 1.595 0.000 5.7778 0.111 0.642 2.385 0.000 5.8500 0.111 0.650 3.212 0.000 5.9222 0.111 0.658 4.014 0.000 5.9944 0.111 0.666 4.734 0.000 6.0667 0.111 0.674 5.326 0.000 6.1389 0.111 0.682 5.771 0.000 6.2111 0.111 0.690 6.087 0.000 6.2833 0.111 0.698 6.427 0.000 6.3556 0.111 0.706 6.713 0.000 6.4278 0.111 0.714 6.986 0.000 6.5000 0.111 0.723 7.249 0.000 6.5722 0.111 0.731 7.503 0.000 6.6444 0.000 0.000 7.748 0.000 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:27 AM Page 8 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.36 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.24 Total Impervious Area:1.12 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.039985 5 year 0.062798 10 year 0.075727 25 year 0.089423 50 year 0.097899 100 year 0.105108 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.024668 5 year 0.038304 10 year 0.049389 25 year 0.065997 50 year 0.080432 100 year 0.096786 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.039 0.017 1950 0.049 0.024 1951 0.088 0.057 1952 0.028 0.015 1953 0.022 0.020 1954 0.034 0.018 1955 0.055 0.018 1956 0.044 0.044 1957 0.035 0.018 1958 0.040 0.020 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:59 AM Page 9 1959 0.034 0.017 1960 0.060 0.049 1961 0.034 0.033 1962 0.021 0.016 1963 0.029 0.019 1964 0.038 0.031 1965 0.027 0.037 1966 0.026 0.019 1967 0.054 0.024 1968 0.034 0.019 1969 0.033 0.018 1970 0.027 0.020 1971 0.029 0.019 1972 0.066 0.051 1973 0.030 0.037 1974 0.032 0.019 1975 0.044 0.017 1976 0.032 0.019 1977 0.004 0.016 1978 0.028 0.020 1979 0.017 0.014 1980 0.062 0.052 1981 0.025 0.019 1982 0.048 0.045 1983 0.043 0.019 1984 0.026 0.016 1985 0.016 0.017 1986 0.069 0.024 1987 0.061 0.047 1988 0.024 0.018 1989 0.016 0.016 1990 0.128 0.050 1991 0.077 0.051 1992 0.030 0.020 1993 0.031 0.016 1994 0.010 0.014 1995 0.044 0.033 1996 0.094 0.055 1997 0.078 0.056 1998 0.018 0.016 1999 0.073 0.051 2000 0.031 0.021 2001 0.006 0.013 2002 0.034 0.032 2003 0.043 0.018 2004 0.056 0.057 2005 0.040 0.018 2006 0.047 0.042 2007 0.095 0.093 2008 0.123 0.053 2009 0.060 0.038 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1282 0.0933 2 0.1227 0.0574 3 0.0951 0.0573 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:59 AM Page 10 4 0.0937 0.0559 5 0.0881 0.0554 6 0.0783 0.0528 7 0.0772 0.0516 8 0.0734 0.0509 9 0.0693 0.0507 10 0.0656 0.0507 11 0.0621 0.0498 12 0.0613 0.0491 13 0.0603 0.0468 14 0.0595 0.0445 15 0.0560 0.0437 16 0.0550 0.0416 17 0.0544 0.0378 18 0.0490 0.0374 19 0.0478 0.0370 20 0.0473 0.0333 21 0.0445 0.0327 22 0.0438 0.0317 23 0.0437 0.0313 24 0.0432 0.0241 25 0.0428 0.0239 26 0.0401 0.0237 27 0.0398 0.0214 28 0.0393 0.0203 29 0.0378 0.0203 30 0.0353 0.0203 31 0.0345 0.0197 32 0.0341 0.0196 33 0.0339 0.0195 34 0.0339 0.0194 35 0.0336 0.0190 36 0.0332 0.0190 37 0.0323 0.0189 38 0.0317 0.0189 39 0.0310 0.0187 40 0.0309 0.0186 41 0.0298 0.0184 42 0.0298 0.0183 43 0.0293 0.0181 44 0.0287 0.0181 45 0.0278 0.0181 46 0.0277 0.0178 47 0.0274 0.0177 48 0.0270 0.0174 49 0.0264 0.0174 50 0.0260 0.0171 51 0.0248 0.0165 52 0.0242 0.0164 53 0.0224 0.0161 54 0.0209 0.0159 55 0.0177 0.0157 56 0.0168 0.0156 57 0.0158 0.0156 58 0.0157 0.0154 59 0.0104 0.0144 60 0.0055 0.0140 61 0.0038 0.0132 DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:59 AM Page 12 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0200 17554 11499 65 Pass 0.0208 16174 8350 51 Pass 0.0216 14972 8104 54 Pass 0.0224 13854 7882 56 Pass 0.0231 12810 7653 59 Pass 0.0239 11813 7428 62 Pass 0.0247 10900 7253 66 Pass 0.0255 10119 7078 69 Pass 0.0263 9390 6847 72 Pass 0.0271 8733 6648 76 Pass 0.0279 8145 6419 78 Pass 0.0286 7599 6186 81 Pass 0.0294 7060 5976 84 Pass 0.0302 6590 5711 86 Pass 0.0310 6149 5416 88 Pass 0.0318 5781 5131 88 Pass 0.0326 5431 4883 89 Pass 0.0334 5097 4588 90 Pass 0.0342 4808 4374 90 Pass 0.0349 4524 4169 92 Pass 0.0357 4252 3968 93 Pass 0.0365 4017 3722 92 Pass 0.0373 3784 3510 92 Pass 0.0381 3546 3328 93 Pass 0.0389 3339 3161 94 Pass 0.0397 3138 2984 95 Pass 0.0405 2952 2774 93 Pass 0.0412 2787 2622 94 Pass 0.0420 2599 2434 93 Pass 0.0428 2447 2233 91 Pass 0.0436 2304 2071 89 Pass 0.0444 2162 1911 88 Pass 0.0452 2026 1778 87 Pass 0.0460 1898 1608 84 Pass 0.0467 1790 1470 82 Pass 0.0475 1688 1331 78 Pass 0.0483 1584 1177 74 Pass 0.0491 1483 1018 68 Pass 0.0499 1380 875 63 Pass 0.0507 1292 737 57 Pass 0.0515 1221 604 49 Pass 0.0523 1155 512 44 Pass 0.0530 1098 413 37 Pass 0.0538 1048 357 34 Pass 0.0546 997 315 31 Pass 0.0554 930 261 28 Pass 0.0562 883 212 24 Pass 0.0570 837 164 19 Pass 0.0578 789 128 16 Pass 0.0586 743 121 16 Pass 0.0593 713 114 15 Pass 0.0601 668 106 15 Pass 0.0609 630 61 9 Pass DRAFT3278.01 Town Place Hotel Detention 9/13/2019 10:59:59 AM Page 13 0.0617 595 59 9 Pass 0.0625 565 58 10 Pass 0.0633 539 57 10 Pass 0.0641 496 55 11 Pass 0.0648 473 54 11 Pass 0.0656 434 54 12 Pass 0.0664 399 53 13 Pass 0.0672 366 52 14 Pass 0.0680 348 52 14 Pass 0.0688 323 51 15 Pass 0.0696 296 50 16 Pass 0.0704 272 50 18 Pass 0.0711 256 49 19 Pass 0.0719 235 47 20 Pass 0.0727 217 46 21 Pass 0.0735 195 46 23 Pass 0.0743 180 45 25 Pass 0.0751 158 45 28 Pass 0.0759 145 44 30 Pass 0.0767 129 44 34 Pass 0.0774 119 43 36 Pass 0.0782 109 43 39 Pass 0.0790 97 41 42 Pass 0.0798 91 40 43 Pass 0.0806 82 39 47 Pass 0.0814 76 38 50 Pass 0.0822 68 38 55 Pass 0.0829 61 37 60 Pass 0.0837 54 35 64 Pass 0.0845 48 34 70 Pass 0.0853 41 34 82 Pass 0.0861 38 33 86 Pass 0.0869 33 30 90 Pass 0.0877 27 28 103 Pass 0.0885 22 21 95 Pass 0.0892 21 19 90 Pass 0.0900 20 18 90 Pass 0.0908 19 16 84 Pass 0.0916 17 14 82 Pass 0.0924 13 11 84 Pass 0.0932 12 3 25 Pass 0.0940 8 0 0 Pass 0.0948 4 0 0 Pass 0.0955 3 0 0 Pass 0.0963 3 0 0 Pass 0.0971 3 0 0 Pass 0.0979 3 0 0 Pass DRAFT3278.01 Town Place Hotel Detention 9/13/2019 11:00:09 AM Page 17 Appendix Predeveloped Schematic DRAFT3278.01 Town Place Hotel Detention 9/13/2019 11:00:10 AM Page 18 Mitigated Schematic DRAFT3278.01 Town Place Hotel Detention 9/13/2019 11:00:10 AM Page 32 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. 2005-2019; 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 TREATMENT BASIN 1 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:16 AM Page 2 General Model Information Project Name:3278.01 Town Place Hotel Treatment Site Name: Site Address: City: Report Date:9/13/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/10/10 Version:4.2.16 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:16 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.35 Pervious Total 0.35 Impervious Land Use acre Impervious Total 0 Basin Total 0.35 Element Flows To: Surface Interflow Groundwater DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:16 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.06 Pervious Total 0.06 Impervious Land Use acre PARKING FLAT 0.29 Impervious Total 0.29 Basin Total 0.35 Element Flows To: Surface Interflow Groundwater DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:16 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.35 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.06 Total Impervious Area:0.29 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.01029 5 year 0.016161 10 year 0.019489 25 year 0.023013 50 year 0.025195 100 year 0.02705 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.114402 5 year 0.14586 10 year 0.167388 25 year 0.195471 50 year 0.217072 100 year 0.239283 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.010 0.152 1950 0.013 0.156 1951 0.023 0.095 1952 0.007 0.080 1953 0.006 0.087 1954 0.009 0.093 1955 0.014 0.105 1956 0.011 0.103 1957 0.009 0.120 1958 0.010 0.094 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:48 AM Page 8 1959 0.009 0.094 1960 0.015 0.098 1961 0.009 0.101 1962 0.005 0.086 1963 0.007 0.098 1964 0.010 0.093 1965 0.007 0.124 1966 0.007 0.081 1967 0.014 0.139 1968 0.009 0.159 1969 0.009 0.113 1970 0.007 0.107 1971 0.008 0.127 1972 0.017 0.136 1973 0.008 0.077 1974 0.008 0.117 1975 0.011 0.129 1976 0.008 0.091 1977 0.001 0.094 1978 0.007 0.116 1979 0.004 0.159 1980 0.016 0.153 1981 0.006 0.119 1982 0.012 0.170 1983 0.011 0.135 1984 0.007 0.086 1985 0.004 0.119 1986 0.018 0.102 1987 0.016 0.156 1988 0.006 0.094 1989 0.004 0.117 1990 0.033 0.220 1991 0.020 0.171 1992 0.008 0.086 1993 0.008 0.073 1994 0.003 0.078 1995 0.011 0.105 1996 0.024 0.116 1997 0.020 0.112 1998 0.005 0.109 1999 0.019 0.231 2000 0.008 0.114 2001 0.001 0.121 2002 0.009 0.149 2003 0.011 0.116 2004 0.014 0.216 2005 0.010 0.099 2006 0.012 0.088 2007 0.024 0.203 2008 0.032 0.168 2009 0.016 0.143 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0330 0.2315 2 0.0316 0.2196 3 0.0245 0.2157 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:48 AM Page 9 4 0.0241 0.2025 5 0.0227 0.1715 6 0.0202 0.1704 7 0.0199 0.1684 8 0.0189 0.1588 9 0.0178 0.1585 10 0.0169 0.1561 11 0.0160 0.1561 12 0.0158 0.1533 13 0.0155 0.1519 14 0.0153 0.1491 15 0.0144 0.1431 16 0.0141 0.1395 17 0.0140 0.1364 18 0.0126 0.1348 19 0.0123 0.1292 20 0.0122 0.1274 21 0.0114 0.1237 22 0.0113 0.1212 23 0.0113 0.1195 24 0.0111 0.1190 25 0.0110 0.1190 26 0.0103 0.1174 27 0.0102 0.1170 28 0.0101 0.1163 29 0.0097 0.1159 30 0.0091 0.1155 31 0.0089 0.1137 32 0.0088 0.1126 33 0.0087 0.1117 34 0.0087 0.1093 35 0.0086 0.1067 36 0.0085 0.1052 37 0.0083 0.1047 38 0.0081 0.1033 39 0.0080 0.1015 40 0.0080 0.1014 41 0.0077 0.0988 42 0.0077 0.0982 43 0.0075 0.0977 44 0.0074 0.0947 45 0.0072 0.0941 46 0.0071 0.0940 47 0.0070 0.0937 48 0.0070 0.0935 49 0.0068 0.0931 50 0.0067 0.0929 51 0.0064 0.0909 52 0.0062 0.0881 53 0.0058 0.0867 54 0.0054 0.0865 55 0.0046 0.0860 56 0.0043 0.0857 57 0.0041 0.0805 58 0.0040 0.0802 59 0.0027 0.0781 60 0.0014 0.0768 61 0.0010 0.0731 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:48 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.0375 acre-feet On-line facility target flow:0.0466 cfs. Adjusted for 15 min:0.0466 cfs. Off-line facility target flow:0.0262 cfs. Adjusted for 15 min:0.0262 cfs. DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:58 AM Page 16 Appendix Predeveloped Schematic DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:58 AM Page 17 Mitigated Schematic DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:05:59 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. 2005-2019; 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 TREATMENT BASIN 2 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:08:50 AM Page 2 General Model Information Project Name:3278.01 Town Place Hotel Treatment Site Name: Site Address: City: Report Date:9/13/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2018/10/10 Version:4.2.16 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:08:50 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.54 Pervious Total 0.54 Impervious Land Use acre Impervious Total 0 Basin Total 0.54 Element Flows To: Surface Interflow Groundwater DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:08:50 AM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.07 Pervious Total 0.07 Impervious Land Use acre PARKING FLAT 0.47 Impervious Total 0.47 Basin Total 0.54 Element Flows To: Surface Interflow Groundwater DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:08:50 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.54 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.07 Total Impervious Area:0.47 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.015876 5 year 0.024935 10 year 0.030068 25 year 0.035506 50 year 0.038872 100 year 0.041734 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.183682 5 year 0.233559 10 year 0.267621 25 year 0.311981 50 year 0.346054 100 year 0.38105 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.016 0.242 1950 0.019 0.252 1951 0.035 0.151 1952 0.011 0.130 1953 0.009 0.140 1954 0.014 0.149 1955 0.022 0.168 1956 0.017 0.166 1957 0.014 0.191 1958 0.016 0.151 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:22 AM Page 8 1959 0.014 0.152 1960 0.024 0.156 1961 0.013 0.162 1962 0.008 0.139 1963 0.011 0.157 1964 0.015 0.150 1965 0.011 0.198 1966 0.010 0.130 1967 0.022 0.224 1968 0.013 0.255 1969 0.013 0.180 1970 0.011 0.171 1971 0.012 0.204 1972 0.026 0.217 1973 0.012 0.124 1974 0.013 0.188 1975 0.017 0.209 1976 0.013 0.145 1977 0.001 0.153 1978 0.011 0.187 1979 0.007 0.256 1980 0.025 0.243 1981 0.010 0.191 1982 0.019 0.273 1983 0.017 0.217 1984 0.010 0.139 1985 0.006 0.191 1986 0.028 0.164 1987 0.024 0.252 1988 0.010 0.152 1989 0.006 0.190 1990 0.051 0.346 1991 0.031 0.272 1992 0.012 0.138 1993 0.012 0.118 1994 0.004 0.127 1995 0.018 0.169 1996 0.037 0.185 1997 0.031 0.178 1998 0.007 0.176 1999 0.029 0.370 2000 0.012 0.182 2001 0.002 0.196 2002 0.013 0.238 2003 0.017 0.185 2004 0.022 0.345 2005 0.016 0.158 2006 0.019 0.140 2007 0.038 0.323 2008 0.049 0.267 2009 0.024 0.232 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0509 0.3698 2 0.0487 0.3456 3 0.0378 0.3449 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:22 AM Page 9 4 0.0372 0.3234 5 0.0350 0.2728 6 0.0311 0.2715 7 0.0306 0.2667 8 0.0292 0.2565 9 0.0275 0.2550 10 0.0260 0.2524 11 0.0247 0.2521 12 0.0243 0.2429 13 0.0239 0.2422 14 0.0236 0.2376 15 0.0222 0.2318 16 0.0218 0.2241 17 0.0216 0.2174 18 0.0194 0.2167 19 0.0190 0.2093 20 0.0188 0.2044 21 0.0177 0.1976 22 0.0174 0.1960 23 0.0174 0.1913 24 0.0172 0.1912 25 0.0170 0.1911 26 0.0159 0.1896 27 0.0158 0.1879 28 0.0156 0.1870 29 0.0150 0.1851 30 0.0140 0.1846 31 0.0137 0.1822 32 0.0135 0.1798 33 0.0135 0.1784 34 0.0135 0.1762 35 0.0133 0.1713 36 0.0132 0.1692 37 0.0128 0.1684 38 0.0126 0.1660 39 0.0123 0.1638 40 0.0123 0.1624 41 0.0118 0.1579 42 0.0118 0.1573 43 0.0116 0.1557 44 0.0114 0.1525 45 0.0110 0.1518 46 0.0110 0.1516 47 0.0109 0.1513 48 0.0107 0.1511 49 0.0105 0.1503 50 0.0103 0.1495 51 0.0099 0.1454 52 0.0096 0.1404 53 0.0089 0.1401 54 0.0083 0.1389 55 0.0070 0.1388 56 0.0067 0.1375 57 0.0063 0.1297 58 0.0062 0.1295 59 0.0041 0.1265 60 0.0022 0.1245 61 0.0015 0.1178 DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:22 AM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.0599 acre-feet On-line facility target flow:0.0756 cfs. Adjusted for 15 min:0.0756 cfs. Off-line facility target flow:0.0427 cfs. Adjusted for 15 min:0.0427 cfs. DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:32 AM Page 16 Appendix Predeveloped Schematic DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:32 AM Page 17 Mitigated Schematic DRAFT3278.01 Town Place Hotel Treatment 9/13/2019 11:09:33 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. 2005-2019; 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 APPENDIX 10 KING COUNTY SURFACE WATER MANUAL WORKSHEETS HC FW, LLC 3926 Aurora Ave. N Seattle, WA 98103 Tyrell Bradley, PE SCJ Alliance (360) 352 - 1465 Town Place Hotel 21 N 4 E 20 34839 Pacific Hwy S Federal Way, WA 38003 09/25/2019 09/25/2019 Duwamish River Core Requirements #1-8, Special Requirements #1-5 On-site stream Everett-Alderwood gravelly sandy loams 6 to 15 percent On-site stormwater improvements to drain to on-site stream 1 Modular Wetland Systems Pipes/Vault 1 Town Place Hotel, Federal Way 09/25/2019 Hylebos Creek Basin Hylebos Creek Basin 1 Western edge of parking lot 1 West edge of parking lot Type 2 - 54 in. catch basin 3 0.66 in. 1 in. 1.5 in. Level 2 26,650 C.F.5.5 ft. 1.36 1 See Appendix 4: Preliminary Construction Plans 2 0.0262 cfs and 0.0427 cfs Bioclean: Modular Wetland Systems See Appendix 4: Preliminary Construction Plans APPENDIX 11 DECLARATION OF COVENANT (NOT INCLUDED AT THIS TIME)