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-2022.0201.PR0004 2021-1129 Stormwater Site Plan Stormwater Site Plan Berry Valley Townhouse Plat Yelm, WA Prepared For: Gerrish Family Revocable Living Trust 14747 Berry Valley Rd SE Yelm, WA 98506 Prepared By: SCJ Alliance 8730 Tallon Lane NE, Suite 200 Lacey, WA 98516 360-352-1465 December 2021 SCJ Alliance December 2021 Stormwater Site Plan Project Information Project: Berry Valley Townhouse Plat Prepared for: Gerrish Family Revocable Living Trust 14747 Berry Valley Rd SE Yelm, WA 98506 Contact Name: Matthew Gerrish Contact Phone: 253.651.9436 Reviewing Agency Jurisdiction: City of Yelm Project Representative Prepared by: SCJ Alliance 8730 Tallon Lane NE, Suite 200 Lacey, WA 98516 360.352.1465 scjalliance.com Contact: Bob Connolly, PE Project Reference: SCJ #21-000227 Path: N:\Projects\5183 Matthew Gerrish\21-000227 Berry Valley Townhomes Plat\Phase 03 - Preliminary Plat\Design\Storm\2021-xxxx Stormwater Site Plan.docx Berry Valley Townhouse Plat Stormwater Site Plan SCJ Alliance December 2021 PROJECT ENGINEER’S CERTIFICATION I hereby certify that this Stormwater Site Plan for the Berry Valley Townhouse Plat project has been prepared by me or under my supervision and meets the minimum standards of the City of Yelm 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: Ronald Boursaw, EIT Date Ronald.Boursaw@scjalliance.com (360) 352-1465 Approved by: Bob Connolly, PE Date Bob.Connolly@scjalliance.com (360) 352-1465 Berry Valley Townhouse Plat Stormwater Site Plan Berry Valley Townhouse Plat 1 of 7 Stormwater Site Plan TABLE OF CONTENTS 1. Project Overview ........................................................................................................ 3 1.1 Summary of Compliance On-Site .......................................................................................... 3 2. Existing Conditions Summary ...................................................................................... 5 2.1 Existing On-Site Conditions ................................................................................................... 5 3. Offsite Analysis Report ............................................................................................... 6 3.1 Qualitative Upstream Analysis .............................................................................................. 6 3.2 Qualitative Downstream Analysis ......................................................................................... 6 4. Permanent Stormwater Control Plan .......................................................................... 6 4.1 Summary Section ................................................................................................................... 6 5. Construction Stormwater Pollution Prevention Plan (C-SWPPP) .................................. 7 6. Special Reports and Studies ........................................................................................ 7 7. Other Permits ............................................................................................................. 8 8. Operation and Maintenance Manual .......................................................................... 8 LIST OF TABLES Table 1: Land Type Designations Existing vs. Proposed ............................................................................ 7 Berry Valley Townhouse Plat Stormwater Site Plan Berry Valley Townhouse Plat 2 of 7 Stormwater Site Plan LIST OF FIGURES Figure 1: Existing Conditions (1990) Figure 2: Existing Conditions (2018) .................................... 5 LIST OF APPENDICES Appendix 1: Site Vicinity Map Appendix 2: Determination of Minimum Requirements Worksheet Appendix 3: Basin Map Exhibits Appendix 4: Construction Plans Appendix 5: Geotechnical Report 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 Berry Valley Townhouse Plat 3 of 8 Stormwater Site Plan 1. PROJECT OVERVIEW The following report was prepared for the Berry Valley Townhouse Plat project in Yelm, WA. This report was prepared to comply with the minimum technical standards and requirements that are set forth in the 2014 Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW) and the 2016 Drainage Design and Erosion Control Manual (DDECM). Project Proponent: Gerrish Family Revocable Living Trust Parcel Numbers: 21721230400 Total Parcel Area: 14.72 Acres Current Zoning: R-4, Residential Required Permits: Grading, Utility, Paving, Building, etc. Site Address: 14747 Berry Valley Road SE Section, Township, Range: Section 24, Township 17 N, Range 1E The proposed Berry Valley Townhouse Plat site is located on one parcel that contains 14.72 acres total. The project is located at west and south side of Berry Valley Rd SE in Yelm, WA. The proposed construction includes 53 lots and interior roadways, frontage improvements, as well as associated driveways, utilities, and stormwater improvements disturbing approximately 6.93 acres. Specifically, the proposed site improvements/construction activities for this project include the following: · Site preparation, grading, and erosion control activities · Demolition of existing gravel areas · Construction of 53 lots · Construction of driveways · Construction of interior roadways · Construction/installation of on-site water quality facilities · Extension of available utilities (i.e., water, sewer, etc.) · Off-site frontage improvements 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 SWMMWW has been prepared and enclosed herein as Appendix 2. The proposed project is considered a new development that will trigger all of the minimum requirements for the new impervious surfaces and the land disturbed. 1.1 SUMMARY OF COMPLIANCE ON-SITE The stormwater design complies with the 9 minimum requirements as follows: Berry Valley Townhouse Plat 4 of 8 Stormwater Site Plan Minimum Requirement #1 – Preparation of Stormwater Site Plans – The Stormwater Site Plan is prepared per the 2014 SWMMWW. Minimum Requirement #2 – Construction Stormwater Pollution Prevention – A pollution prevention plan will be completed and included herein as Appendix 7 at the time of the civil permit submittal which will describe the 13 required elements. Further, an erosion control plan has been prepared and included as part of the engineering construction plan set in Appendix 4. 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. Minimum Requirement #3 – Source Control of Pollution – BMPs listed below are the minimum required for the site, additional BMPs not listed here may need to be implemented the meet the minimum requirements discussed in the 2014 SWMMWW. · S411 BMPs for Landscaping and Lawn/Vegetation Management · S417 BMPs for Maintenance of Stormwater Drainage and Treatment Systems Minimum Requirement #4 – Preservation of Natural Drainage Systems and Outfalls – Currently, stormwater runoff throughout the site sheet flows to the west side of the parcel. The stormwater runoff then enters the wetland adjacent to parcel. After construction, the stormwater runoff from the proposed improvements will be collected, treated, and released to the wetland at predeveloped rates. Minimum Requirement #5 – On-site Stormwater Management – In accordance with Minimum Requirement #7, this project is not flow control exempt. The project triggers all of the requirements and therefore must choose to meet the LID performance standard or apply on-site stormwater BMPs following List #2. This project will utilize List #2. Lawn and Landscaped Areas: · Per the 2014 SWMMWW manual, BMP T5.13: Post Construction Soil Quality and Depth will be utilized to the maximum extent practicable. See landscape plans for details. Roofs: · Full Dispersion (BMP T5.30B): Full dispersion is not feasible for this project site. Full dispersion requires that the site protects at least 65% of the site in a forest or native condition. For this reason alone this BMP is not feasible. · Bioretention (BMP T7.30): Bioretention systems are not feasible for this project site. A bioretention facility requires a treatment depth that will not allow for the minimum separation to ground water from bottom of the facility. · Downspout Dispersion Systems (BMP T5.10B): Downspout dispersion is not feasible for this project. Dispersion requires a minimum vegetated path of 50 feet and for this reason alone it is not feasible. · Perforated Stub-out Connections (BMP T5.10C): Perforated stub outs is not feasible for this project due to the total depth of the system. · The roof areas will be collected and flow to a general stormwater infiltration pond. Other Hard Surfaces: · Full Dispersion (BMP T5.30): Full Dispersion is not feasible for this project due to the percentage of parcel development. · Permeable Pavement (BMP T5.15): Permeable pavement is not feasible for this project due to the pollution generating impervious surfaces require treatment prior to infiltration. Permeable pavement would not allow for treatment prior to infiltration. Berry Valley Townhouse Plat 5 of 8 Stormwater Site Plan · Bioretention (BMP T7.30): Bioretention systems are not feasible for this project site. A bioretention facility requires a treatment depth that will not allow for the minimum separation to ground water from bottom of the facility. · Sheet Flow Dispersion (BMP T5.12): Sheet flow dispersion is not feasible for this project due to required flow path lengths being infeasible. · All pollution generating hard surfaces will be collected and treated in a modular wetland facility prior to flowing into a infiltration pond. Minimum Requirement #6 – Runoff Treatment – The proposed project will construct over 5,000 s.f. of pollution- generating impervious surface, therefore a stormwater treatment facility is required. The proposed project is not considered a high-use site and therefore does not require oil control. According to Volume V Section 2.1 of the SWMMWW, a commercial site with an expected average daily traffic (ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross building area. Phosphorus control is not required by the jurisdiction. The proposed project is not an industrial, or multi-family residential project and therefore does not require enhanced treatment. Therefore, basic treatment is required for this project. Basic treatment will be provided for the project through the use of the modular wetland treatment facilities. Minimum Requirement #7 – Flow Control – The project is not flow control exempt and therefore must meet this requirement. Flow control will be met by infiltrating the stormwater runoff from the proposed project improvements on-site. See Section 4 of this report for more information. Minimum Requirement #8 – Wetlands Protection – There are wetlands on the project site to the north, the project currently discharges to the wetlands. After development the project will infiltrate the stormwater runoff and therefore reduce the amount of runoff from the project flow. Minimum Requirement #9 – Operation and Maintenance – An operations and maintenance manual will be attached herein as Appendix 6 at the time of civil permit submittal. 2. EXISTING CONDITIONS SUMMARY 2.1 EXISTING ON-SITE CONDITIONS The subject site is +/- 14.72 acres in size. Topography within the property is generally flat throughout sloping to the west at slopes between 0 and 5%. The site has remained largely undeveloped since at least 1990 having only a single residential home on it. Vegetation appears to be minimal, with some grasses. No developments have been added since then. See the figures below. Figure 1: Existing Conditions (1990) Figure 2: Existing Conditions (2021) Berry Valley Townhouse Plat 6 of 8 Stormwater Site Plan Flood Hazard Zone Flood Zones: The project parcel is located within Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) Panel No. 53067C0335E. According to the FIRM Map, the parcel is determined to be in an area of minimal flood hazard. See Appendix 8 for the FIRM Map. On-Site Soils Information A water table study was conducted by Terra Associates in February 2021. Seven test pits were conducted to depths of approximately 11 feet. A Natural Resources Conservation Service (NRCS) Soils report was utilized to determine infiltration rates for the preliminary plat planning. The NRCS soils report shows 1.98 in/hr to 5.95 in/hr. An infiltration rate of 2 in/hr for design. See Appendix 5 for the Water Table Study and the NRCS report. 3. OFFSITE ANALYSIS REPORT 3.1 QUALITATIVE UPSTREAM ANALYSIS The parcel area and the surrounding parcels appear to be relatively flat. It is not anticipated that there is any off- site run-on from the adjacent parcels. 3.2 QUALITATIVE DOWNSTREAM ANALYSIS After construction, stormwater runoff from the project areas will sheet flow across the site and collected in catch basins and treated in a modular wetland system then infiltrated into the native soil. In the event that the system fails or overflows, stormwater runoff will sheet flow directly to the west and into the neighboring wetland as it does today. 4. PERMANENT STORMWATER CONTROL PLAN 4.1 SUMMARY SECTION The proposed project follows the development requirements stated in the 2014 SWMMWW. Following Figure 2.4.1 (See Appendix 2), this project classifies as new development that triggers all of the minimum requirements. The site has less than 35% or more of existing impervious coverage, and the project will add more than 5,000 s.f. of new impervious surfaces. See Appendix 4 for the proposed stormwater facility location 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). LAND TYPE DESIGNATIONS AREA (ACRES) % OF TOTAL AREA Existing Areas 14.72 100 Impervious 0.00 0.00 Pervious 14.72 100.00 Berry Valley Townhouse Plat 7 of 8 Stormwater Site Plan Proposed Areas 14.72 100 Roof 1.87 12.70 Asphalt 2.08 14.13 Sidewalk 1.13 7.68 Landscape 1.85 12.57 Undeveloped 7.79 52.92 Table 1: Land Type Designations Existing vs. Proposed Performance Standards and Goals Following Figure 2.4.1 – Flow Chart for Determining Requirements for New Development, the project site triggers the use of Minimum Requirements #1-9. All of the stormwater runoff from the proposed project improvements will be collected, treated on-site with basic treatment (only the pollution-generating impervious surfaces), and infiltrated on-site. Flow control is required for this project. Flow Control System Flow control is required for the proposed project and will be provided through infiltrating 100% of the onsite stormwater runoff. A storm facility was sized to infiltrate 100% of the proposed projects improvements runoff. A modular wetland system will be utilized for treatment prior to infiltration. See plans for facility location. See Appendix 9 for the WWHM Report. Water Quality System Basic treatment will be provided for the proposed development through the use of a modular wetland system. 100% of the stormwater runoff from the proposed project improvements will infiltrate through the native soil after going through the modular wetland system and therefore will meet the treatment requirements and infiltration requirements. It is assumed that the stormwater runoff from the majority of the sidewalk areas will flow across the asphalt parking areas, and therefore were included in the treatment facility sizing. See Appendix 3 for the proposed treatment area. The drainage plan with the locations of the treatment facility has been included as Appendix 4. See Appendix 9 for the WWHM report. Conveyance System Analysis and Design The only on-site conveyance are the roof drain pipes that are 6” in diameter and a 8” storm drain pipe that conveys the roadway runoff to the storm treatment facility. 5. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (C- SWPPP) A SWPPP will be attached in Appendix 7 at the time of civil permit submittal. 6. SPECIAL REPORTS AND STUDIES See Appendix 5 for the NRCS Soils report and Water Table Study. No other special reports or studies were required for this project. Berry Valley Townhouse Plat 8 of 8 Stormwater Site Plan 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. OPERATION AND MAINTENANCE MANUAL The owner of the Berry Valley Townhouse Plat will be responsible in maintaining all stormwater facilities on-site. An operation and maintenance manual will be included herein as Appendix 6 at time of civil permit submittal. END OF STORMWATER SITE PLAN SCJ Alliance October 2020 Page 1 APPENDIX 1 SITE VICINITY MAP 8730 Tallon Lane NE, Suite 200  Lacey, WA 98516  Office 360.352.1465  Fax 360.352.1509  scjalliance.com APPENDIX 2 DETERMINATION OF MINIMUM REQUIREMENTS WORKSHEET Figure I-2.4.1 Flow Chart for Determining Requirements for New Development D E P A R T M E N T O F E C O L O G Y S t a t e o f W a s h i n g t o n Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. Figure I-2.4.1 Flow Chart for Determining Requirements for New Development Revised June 2015 Does the site have 35% or more of existing impervious coverage? Does the project result in 5,000 square feet, or greater, of new plus replaced hard surface area? All Minimum Requirements apply to the new and replaced hard surfaces and converted vegetation areas. Does the project convert 3 4 acres or more of vegetation to lawn or landscaped areas, or convert 2.5 acres or more of native vegetation to pasture? Minimum Requirements #1 through #5 apply to the new and replaced hard surfaces and the land disturbed. See Redevelopment Minimum Requirements and Flow Chart (Figure I-2.4.2). Does the project result in 2,000 square feet, or greater, of new plus replaced hard surface area? Does the project have land disturbing activities of 7,000 square feet or greater? Minimum Requirement #2 applies. Start Here Yes No No No No No Yes Yes Yes Yes 2014 Stormwater Management Manual for Western Washington Volume I -Chapter 2 -Page 37 APPENDIX 3 BASIN MAP EXHIBITS ROAD A ROAD BPROPOSED ON-SITE BASIN 1 AREAS:ROOF AREA:0.29 ACRESASPHALT AREA: 0.29 ACRESCONCRETE AREA:0.22 ACRESLANDSCAPE AREA:0.21 ACRESTOTAL:1.01 ACRESJOB 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"=50'DECEMBER, 202121-00022721-000227 Pr. Conditions Map.dwgPROPOSED CONDITIONS MAPBERRY VALLEY TOWNHOUSE PLAT, OLYMPIA, WAEX-022SCALE IN FEET050100PROPOSED ON-SITE BASIN 2 AREAS:ASPHALT AREA:1.17 ACRESCONCRETE AREA:0.91 ACRESLANDSCAPE AREA:0.10 ACRESTOTAL:2.18 ACRESPROPOSED ON-SITE BASIN 3 AREAS:ROOF AREA:0.81 ACRESLANDSCAPE AREA:0.48 ACRESSTORM FACILITY:0.36 ACRESTOTAL:1.65 ACRESPROPOSED FRONTAGE BASIN 4 AREAS:ASPHALT AREA:0.43 ACRESEXTRA ASPHALT AREA:0.19 ACRESPERVIOUS AREA:0.26 ACRESTOTAL:0.88 ACRESPROPOSED ON-SITE BASIN 3 AREAS:ROOF AREA:0.77 ACRESLANDSCAPE AREA:0.44 ACRESTOTAL:1.21 ACRES APPENDIX 4 CONSTRUCTION PLANS APPENDIX 5 GEOTECHNICAL REPORT United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Thurston County Area, WashingtonNatural Resources Conservation Service November 1, 2021 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Thurston County Area, Washington................................................................13 33—Everett very gravelly sandy loam, 8 to 15 percent slopes...................13 74—Nisqually loamy fine sand, 3 to 15 percent slopes...............................14 110—Spanaway gravelly sandy loam, 0 to 3 percent slopes......................15 112—Spanaway stony sandy loam, 0 to 3 percent slopes..........................16 113—Spanaway stony sandy loam, 3 to 15 percent slopes........................17 References............................................................................................................19 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 51991405199220519930051993805199460519954051996205199140519922051993005199380519946051995405199620527890 527970 528050 528130 528210 528290 528370 528450 528530 528610 527890 527970 528050 528130 528210 528290 528370 528450 528530 528610 46° 56' 58'' N 122° 38' 1'' W46° 56' 58'' N122° 37' 25'' W46° 56' 42'' N 122° 38' 1'' W46° 56' 42'' N 122° 37' 25'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 150 300 600 900 Feet 0 50 100 200 300 Meters Map Scale: 1:3,430 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Thurston County Area, Washington Survey Area Data: Version 15, Aug 31, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 18, 2020—Jul 20, 2020 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 33 Everett very gravelly sandy loam, 8 to 15 percent slopes 1.7 4.0% 74 Nisqually loamy fine sand, 3 to 15 percent slopes 33.5 80.3% 110 Spanaway gravelly sandy loam, 0 to 3 percent slopes 2.9 7.0% 112 Spanaway stony sandy loam, 0 to 3 percent slopes 1.2 2.8% 113 Spanaway stony sandy loam, 3 to 15 percent slopes 2.4 5.8% Totals for Area of Interest 41.7 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. Custom Soil Resource Report 11 The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Thurston County Area, Washington 33—Everett very gravelly sandy loam, 8 to 15 percent slopes Map Unit Setting National map unit symbol: 2t62b Elevation: 30 to 900 feet Mean annual precipitation: 35 to 91 inches Mean annual air temperature: 48 to 52 degrees F Frost-free period: 180 to 240 days Farmland classification: Farmland of statewide importance Map Unit Composition Everett and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Everett Setting Landform:Moraines, eskers, kames Landform position (two-dimensional):Shoulder, footslope Landform position (three-dimensional):Crest, base slope Down-slope shape:Convex Across-slope shape:Convex Parent material:Sandy and gravelly glacial outwash Typical profile Oi - 0 to 1 inches: slightly decomposed plant material A - 1 to 3 inches: very gravelly sandy loam Bw - 3 to 24 inches: very gravelly sandy loam C1 - 24 to 35 inches: very gravelly loamy sand C2 - 35 to 60 inches: extremely cobbly coarse sand Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 3.2 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: A Ecological site: F002XA004WA - Puget Lowlands Forest Forage suitability group: Droughty Soils (G002XN402WA), Droughty Soils (G002XS401WA), Droughty Soils (G002XF403WA) Other vegetative classification: Droughty Soils (G002XN402WA), Droughty Soils (G002XS401WA), Droughty Soils (G002XF403WA) Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Alderwood Percent of map unit:10 percent Landform:Hills, ridges Landform position (two-dimensional):Shoulder Landform position (three-dimensional):Nose slope, talf Down-slope shape:Convex, linear Across-slope shape:Convex Hydric soil rating: No Indianola Percent of map unit:10 percent Landform:Terraces, kames, eskers Landform position (three-dimensional):Riser Down-slope shape:Linear Across-slope shape:Linear Hydric soil rating: No 74—Nisqually loamy fine sand, 3 to 15 percent slopes Map Unit Setting National map unit symbol: 2ndc9 Elevation: 160 to 1,310 feet Mean annual precipitation: 40 to 60 inches Mean annual air temperature: 50 degrees F Frost-free period: 150 to 200 days Farmland classification: Farmland of statewide importance Map Unit Composition Nisqually and similar soils:85 percent Minor components:5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nisqually Setting Landform:Terraces Parent material:Sandy glacial outwash Typical profile H1 - 0 to 5 inches: loamy fine sand H2 - 5 to 31 inches: loamy fine sand H3 - 31 to 60 inches: loamy sand Properties and qualities Slope:3 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Custom Soil Resource Report 14 Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 4.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: A Ecological site: R002XA006WA - Puget Lowlands Prairie Forage suitability group: Droughty Soils (G002XS401WA) Other vegetative classification: Droughty Soils (G002XS401WA) Hydric soil rating: No Minor Components Yelm Percent of map unit:3 percent Hydric soil rating: No Norma Percent of map unit:2 percent Landform:Depressions Other vegetative classification:Wet Soils (G002XS101WA) Hydric soil rating: Yes 110—Spanaway gravelly sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2ndb6 Elevation: 330 to 1,310 feet Mean annual precipitation: 35 to 65 inches Mean annual air temperature: 50 degrees F Frost-free period: 150 to 200 days Farmland classification: Prime farmland if irrigated Map Unit Composition Spanaway and similar soils:100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Spanaway Setting Landform:Terraces, outwash plains Parent material:Volcanic ash over gravelly outwash Typical profile H1 - 0 to 15 inches: gravelly sandy loam H2 - 15 to 20 inches: very gravelly loam Custom Soil Resource Report 15 H3 - 20 to 60 inches: extremely gravelly sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 3.8 inches) Interpretive groups Land capability classification (irrigated): 3s Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: R002XA006WA - Puget Lowlands Prairie Forage suitability group: Droughty Soils (G002XS401WA) Other vegetative classification: Droughty Soils (G002XS401WA) Hydric soil rating: No 112—Spanaway stony sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2ndb8 Elevation: 660 to 1,310 feet Mean annual precipitation: 35 to 65 inches Mean annual air temperature: 50 degrees F Frost-free period: 150 to 200 days Farmland classification: Farmland of statewide importance Map Unit Composition Spanaway and similar soils:100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Spanaway Setting Landform:Terraces, outwash plains Parent material:Volcanic ash over gravelly outwash Typical profile H1 - 0 to 16 inches: stony sandy loam H2 - 16 to 22 inches: very gravelly sandy loam H3 - 22 to 60 inches: extremely gravelly sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95 in/hr) Custom Soil Resource Report 16 Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 4.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: A Ecological site: R002XA006WA - Puget Lowlands Prairie Forage suitability group: Droughty Soils (G002XS401WA) Other vegetative classification: Droughty Soils (G002XS401WA) Hydric soil rating: No 113—Spanaway stony sandy loam, 3 to 15 percent slopes Map Unit Setting National map unit symbol: 2ndb9 Elevation: 660 to 1,310 feet Mean annual precipitation: 35 to 65 inches Mean annual air temperature: 50 degrees F Frost-free period: 150 to 200 days Farmland classification: Farmland of statewide importance Map Unit Composition Spanaway and similar soils:100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Spanaway Setting Landform:Terraces, outwash plains Parent material:Volcanic ash over gravelly outwash Typical profile H1 - 0 to 16 inches: stony sandy loam H2 - 16 to 22 inches: very gravelly sandy loam H3 - 22 to 60 inches: extremely gravelly sand Properties and qualities Slope:3 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 4.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Custom Soil Resource Report 17 Hydrologic Soil Group: A Ecological site: R002XA006WA - Puget Lowlands Prairie Forage suitability group: Droughty Soils (G002XS401WA) Other vegetative classification: Droughty Soils (G002XS401WA) Hydric soil rating: No Custom Soil Resource Report 18 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 19 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 20 February 2, 2021 Project No. T-8458 Mr. Evan Mann SoundBuilt Northwest, LLC P.O. Box 73790 Puyallup, Washington 98373 Subject: Limited Geotechnical Evaluation Stormwater Infiltration Gerrish Property Yelm, Washington Dear Mr. Mann: As requested, we performed a limited geotechnical evaluation at the subject property. In accordance with your email, dated January 4, 2021, our scope of work for this initial phase of the project is to explore subsurface conditions at the site in order to evaluate the capability of the site soils to infiltrate stormwater runoff. The site is a 14.72-acre parcel located at 14747 – Berry Valley Road SE in Yelm, Washington. The site location is shown on Figure 1. The site is mostly open, undeveloped pastureland. The site’s southeastern corner is developed with a single-family residence and two outbuildings. Vegetation predominantly consists of grasses with brush located along the site’s western margin. Site topography is generally flat. No ponded or flowing surface water was observed at the time of our visit. SUBSURFACE CONDITIONS On January 15, 2021, we observed soil and groundwater conditions at 7 test pits excavated to a maximum depth of approximately 11 feet below existing site grades. The test pits were advanced using a 300 series excavator. The approximate test pit location is shown on Figure 2. A geotechnical engineer from our office conducted the field exploration. Our representative classified the soil conditions encountered, maintained a log of each test pit, obtained representative soil samples, and observed water levels during excavation. Slotted PVC standpipes were installed at three test pit locations to facilitate future monitoring of groundwater levels. All soil samples were visually classified in accordance with the Unified Soil Classification System (USCS) described on Figure 3. The Test Pit Logs are attached as Figures 4 through 10. 12220 113th Avenue NE, Ste. 130, Kirkland, Washington 98034 Phone (425) 821‐7777 • Fax (425) 821‐4334 Mr. Evan Mann February 2, 2021 Project No. T-8458 Page No. 2 Representative soil samples obtained from the test pits were placed in closed containers and taken to our laboratory for further examination and testing. The moisture content of each sample and organic contents of two samples are reported on the Test Pit Logs. Grain size analyses were performed on selected samples. The results are shown on Figures 11 and 12. Soils The soils observed during our investigation consist of approximately 4 to 9 inches of sod overlying loose silty sand and silt to depths of 3 to 4.5 feet. TP-1 indicated the silty sand is loose to medium dense to a depth of 6 feet. Organic content testing indicates the silty sand has low organic contents ranging from 4.0 to 4.9 percent. Underlying the upper silty sand and silt, we observed medium-dense outwash soils composed of gravel with silt, silty gravel and sand with silt to the termination depths of each test pit. The Geologic Map of the Centralia Quadrangle, Washington, by Henry W. Schasse (1987) shows site soils mapped as Vashon outwash gravel (Qdvg). The soils at the site generally correlate with the published description of these soils. Groundwater We observed groundwater seepage flows during the excavation of each of the test pits at the site. Observed seepage depths ranged from 3 feet at TP-2 and TP-7 to 9 feet at the location of TP-1. Seepage flow rates were generally heavy, with light seepage becoming heavy with depths noted during excavation of TP-5 and TP-7. Groundwater levels at the site are likely controlled by flow levels in nearby Thompson Creek, as indicated by shallower groundwater depths at the western test pit locations. Slotted two-inch PVC standpipes were installed at the locations of Test Pits TP-2, TP-5, and TP-7 to facilitate monitoring of static groundwater levels through the winter wet season. Groundwater seepage levels observed during test pit excavation and subsequent measured levels are shown in Table 1. Table 1 – Groundwater Level Measurements Test Pit Groundwater Levels Depth in feet (all depths below ground surface) At Time of Excavation (1/15/2021) 1/26/2021 TP-2 3 3.10 TP-5 5.5 6.27 TP-7 3 4.79 Mr. Evan Mann February 2, 2021 Project No. T-8458 Page No. 3 DISCUSSION The City of Yelm adopted the 2012 (amended 2014) Department of Ecology Stormwater Management Manual for Western Washington (SMMWW) for stormwater design requirements. For roof runoff infiltration facilities, the SMMWW requires a minimum of three feet or more of permeable soil from the proposed final grade to the seasonal high groundwater table. Based on our observations and water level measurements, this criteria for roof runoff infiltration trench construction would not be met at the site. Accordingly, the site soils and groundwater conditions are not favorable for roof runoff flow control using SMMWW infiltration BMP T5.10A in our opinion. Permeable pavements will be feasible at the site using infiltration rates reduced by the low-permeability characteristics of the site’s silts and silty sands. Based on our experience with similar sites and pilot infiltration tests conducted on similar soils, an infiltration rate of 0.1 inch/hour can be used to design aggregate storage reservoirs below permeable pavements. LIMITATIONS We prepared this report in accordance with generally accepted geotechnical engineering practices. No other warranty, expressed or implied, is made. This report is the copyrighted property of Terra Associates, Inc., and is intended for the specific application to the Gerrish Property project in Yelm, Washington and for the exclusive use of SoundBuilt Northwest, LLC and their authorized representatives. Sincerely yours, TERRA ASSOCIATES, INC. Kevin P. Roberts. P.E. Geotechnical Engineer Carolyn S. Decker, P.E. Project Engineer Encl: Figure 1 – Vicinity Map Figure 2 – Exploration Location Plan Figure 3 – Unified Soil Classification System Figures 4 through 10 – Test Pit Logs Figures 11 and 12 – Grain Size Analyses © 2020 Microsoft Corporation © 2020 TomTom SITE Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and Figure 1 VICINITY MAP 0 1000 2000 APPROXIMATE SCALE IN FEET REFERENCE: https://www.bing.com/maps ACCESSED 1/20/2020 Proj.No. T-8458 Date: FEB 2021 YELM, WASHINGTON GERRISH PROPERTY © 2020 Microsoft Corporation © 2020 Maxar ©CNES (2020) Distribution Airbus DS © 2020 TomTom TP-1 TP-2 TP-3 TP-4 TP-5 TP-6TP-7 REFERENCE: REFERENCE ONLY AND SHOULD NOT BE USED FOR DESIGN OR CONSTRUCTION PURPOSES. DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FOR NOTE: THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND LEGEND: 0 150 300 APPROXIMATE SCALE IN FEETSITE PLAN PROVIDED BY BING MAPS. APPROXIMATE TEST PIT LOCATION Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and EXPLORATION LOCATION PLAN Figure 2Proj.No. T-8458 Date: FEB 2021 YELM, WASHINGTON GERRISH PROPERTY Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and MAJOR DIVISIONS LETTER SYMBOL TYPICAL DESCRIPTION GRAVELS More than 50% of coarse fraction is larger than No. 4 sieve Clean Gravels (less than 5% fines) GW Well-graded gravels, gravel-sand mixtures, little or no fines. GP Poorly-graded gravels, gravel-sand mixtures, little or no fines. Gravels with fines GM Silty gravels, gravel-sand-silt mixtures, non-plastic fines. GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. SANDS More than 50% of coarse fraction is smaller than No. 4 sieve Clean Sands (less than 5% fines) SW Well-graded sands, sands with gravel, little or no fines. SP Poorly-graded sands, sands with gravel, little or no fines. Sands with fines SM Silty sands, sand-silt mixtures, non-plastic fines. SC Clayey sands, sand-clay mixtures, plastic fines. SILTS AND CLAYS Liquid Limit is less than 50% ML Inorganic silts, rock flour, clayey silts with slight plasticity. CL Inorganic clays of low to medium plasticity. (Lean clay) OL Organic silts and organic clays of low plasticity. SILTS AND CLAYS Liquid Limit is greater than 50% MH Inorganic silts, elastic. CH Inorganic clays of high plasticity. (Fat clay) OH Organic clays of high plasticity. HIGHLY ORGANIC SOILS PT Peat.COARSE GRAINED SOILSMore than 50% material largerthan No. 200 sieve sizeFINE GRAINED SOILSMore than 50% material smallerthan No. 200 sieve sizeDEFINITION OF TERMS AND SYMBOLS COHESIONLESSCOHESIVE Standard Penetration Density Resistance in Blows/Foot Very Loose 0-4 Loose 4-10 Medium Dense 10-30 Dense 30-50 Very Dense >50 Standard Penetration Consistancy Resistance in Blows/Foot Very Soft 0-2 Soft 2-4 Medium Stiff 4-8 Stiff 8-16 Very Stiff 16-32 Hard >32 2" OUTSIDE DIAMETER SPILT SPOON SAMPLER 2.4" INSIDE DIAMETER RING SAMPLER OR SHELBY TUBE SAMPLER WATER LEVEL (Date) Tr TORVANE READINGS, tsf Pp PENETROMETER READING, tsf DD DRY DENSITY, pounds per cubic foot LL LIQUID LIMIT, percent PI PLASTIC INDEX N STANDARD PENETRATION, blows per foot UNIFIED SOIL CLASSIFICATION SYSTEM Figure 3Proj.No. T-8458 Date: FEB 2021 YELM, WASHINGTON GERRISH PROPERTY Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 4 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-1 NA 9 Feet 3 Feet Loose to Medium Dense Medium Dense 7 inches SOD. Dark brown silty SAND, fine to medium grained, moist. (SM) Gray-brown Gray-brown GRAVEL with fine to coarse sand, fine to coarse gravel, moist to wet. (GP) Wet Total depth 11 feet due to caving. Heavy groundwater seepage at 9 feet. Caving at 3 feet. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 5 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-2 NA 3 Feet 2 Feet Medium Dense Loose Medium Dense 5 inches SOD. Dark brown-gray silty SAND, fine to medium grained, moist. (SM) Wet Brown-gray GRAVEL with silt and fine to medium sand, fine to coarse gravel, wet. (GP-GM) Total depth 8 feet due to caving. Heavy groundwater seepage at 3 feet. Caving at 2 feet. Two-inch slotted PVC standpipe installed with 3.75 feet stickup. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 6 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-3 NA 4.5 Feet 3 Feet Loose Medium Dense 5 inches SOD. Dark brown-gray silty SAND, fine to medium grained, moist. (SM) Gray-brown SAND with silt, fine to medium grained, wet. (SP-SM) Total depth 9 feet due to caving. Heavy groundwater seepage at 4.5 feet. Caving at 3 feet. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 7 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-4 NA 6 Feet 1 Foot Loose Medium Dense 9 inches SOD. Dark brown-gray silty SAND, fine to medium grained, moist to wet. (SM) Brown mottled SAND, fine to medium grained, moist. (SP) Wet Brown-gray GRAVEL with silt and fine to medium sand, fine to coarse gravel, wet. (GP- GM) Total depth 11 feet due to caving. Heavy groundwater seepage at 6 feet. Caving at 1 foot. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 8 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-5 NA 5.5 Feet 2 Feet Loose Medium Dense 4 inches SOD. Dark brown-gray silty SAND, fine to medium grained, moist. (SM) Brown mottled SILT with fine sand, stratified, non-plastic, wet. (ML) Wet Brown silty GRAVEL with fine to medium sand, fine to coarse gravel, wet. (GM) Total depth 11 feet due to caving. Light groundwater seepage at 5.5 feet becoming heavy at 8 feet, Caving at 2 feet. Two-inch slotted PVC standpipe installed with 2.96 feet stickup. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 9 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-6 NA 6.5 Feet 4 Feet Loose Medium Dense 8 inches SOD. Dark brown-gray SILT with fine sand, non-plastic, moist. (ML) Brown GRAVEL with medium sand, fine gravel, moist. (GP) Wet Total depth 10 feet due to caving. Heavy groundwater seepage at 6.5 feet. Caving at 4 feet. Sample No.Depth (ft)PROJECT NAME: PROJ. NO: LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 10 T-8458 KPR Yelm, Washington Grass January 15, 2021 Gerrish Property LOG OF TEST PIT NO. TP-7 NA 3 Feet 1 Foot Loose Medium Dense 5 inches SOD. Dark brown-gray SILT with fine sand, non-plastic, moist. (ML) Brown silty SAND, fine to medium grained, wet. (SM) Brown silty GRAVEL with fine to medium sand, fine to coarse gravel, wet. (GM) Total depth 10 feet due to caving. Light groundwater seepage at 3 feet becoming heavy at 8 feet.. Caving at 1 foot. Two-inch slotted PVC standpipe installed with 0.86 feet stickup. Tested By: FQ NONE IMaterial Descriptiono SAND:.n, Silty SANDProject No. T-8458 Client: SoundBuilt Northwest Remarks:Project: Gerrish Property.o Location: TP -1 Depth: -8 Feeto Location: TP -4 Depth: -6 Feet.A Location: TP -6 Depth: -2 FeetTerra Associates, Inc.Kirkland, WA Figure Tested By: FQ Tested By: Particle Size Distribution Report c c c C c c c' CQ o �Qy SQ Q Q Q 100 I II I I I I I I I I I l l 90 ! I I 1 II I 1! I f l I l I 1 I I I I 1 l 1 1 l l 1 I 80 I I i I I I I! I ] I I I I I I I I 70 I I I I I I I I I I! I I I I I I I I I I I I I E I LU 60 I i I I P I I l I I I I I I I I I I I I I I I I II I [ I ! I I Z 50 I I 1 1 1 l 11 1 I I ! I I I LU I I I I f I LU 40 I I I I I I I I I I I I I I I 30 I I I I I ! ! f 20 I I I I P I I I I I I I E ! I 1 1 1 I 1 1 I I 1 10 f I I I I I I I I ! I 1 1 I I I I 0 1 I l i i 100 10 1 0.1 0.01 0.001 GRAIN SIZE - mm. % Gravel % Sand % Fines %+3" Coarse Fine Coarse Medium Fine Silt clay 0 0.0 25.1 28.8 7.1 20.5 12.9 5.6 LL PL D gs D D Dan D DIp C C 01 25.6563 10.6850 6.2745 0.8100 0.3539 0.2568 0.24 41.61 I Material Description USCS AASHTO GP -GM o GRAVEL with silt and sand Project No. T-8458 Client: SoundBuilt Northwest Remarks: Project: Gerrish Property 'o Location: TP -6 Depth: -5 Feet Terra Associates, Inc. Kirkland, WA Figure 12 Tested By: APPENDIX 6 OPERATIONS AND MAINTENANCE MANUAL APPENDIX 7 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN APPENDIX 8 FEMA FLOOD INSURANCE MAP National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 11/1/2021 at 5:14 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 122°37'59"W 46°56'56"N 122°37'22"W 46°56'32"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 APPENDIX 9 DESIGN CALCULATIONS AND COMPUTATIONS WWHM2012 PROJECT REPORT 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 2 General Model Information Project Name:21-000227 Basin 2 Site Name: Site Address: City: Report Date:11/29/2021 Gage:Eaton Creek Data Start:1955/10/01 Data End:2011/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Pasture, Flat 2.53 Pervious Total 2.53 Impervious Land Use acre Impervious Total 0 Basin Total 2.53 Element Flows To: Surface Interflow Groundwater 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.1 Pervious Total 1.1 Impervious Land Use acre ROADS FLAT 0.62 ROOF TOPS FLAT 0.81 Impervious Total 1.43 Basin Total 2.53 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 5 Routing Elements Predeveloped Routing 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 6 Mitigated Routing Trapezoidal Pond 1 Bottom Length:80.00 ft. Bottom Width:70.00 ft. Depth:3 ft. Volume at riser head:0.3006 acre-feet. Infiltration On Infiltration rate:2 Infiltration safety factor:1 Wetted surface area On Total Volume Infiltrated (ac-ft.):384.539 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):384.539 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Side slope 1:3 To 1 Side slope 2:3 To 1 Side slope 3:3 To 1 Side slope 4:3 To 1 Discharge Structure Riser Height:2 ft. Riser Diameter:18 in. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.128 0.000 0.000 0.000 0.0333 0.129 0.004 0.000 0.260 0.0667 0.129 0.008 0.000 0.262 0.1000 0.130 0.013 0.000 0.263 0.1333 0.131 0.017 0.000 0.264 0.1667 0.132 0.021 0.000 0.266 0.2000 0.132 0.026 0.000 0.267 0.2333 0.133 0.030 0.000 0.269 0.2667 0.134 0.035 0.000 0.270 0.3000 0.134 0.039 0.000 0.271 0.3333 0.135 0.044 0.000 0.273 0.3667 0.136 0.048 0.000 0.274 0.4000 0.137 0.053 0.000 0.276 0.4333 0.137 0.057 0.000 0.277 0.4667 0.138 0.062 0.000 0.279 0.5000 0.139 0.066 0.000 0.280 0.5333 0.139 0.071 0.000 0.282 0.5667 0.140 0.076 0.000 0.283 0.6000 0.141 0.080 0.000 0.284 0.6333 0.142 0.085 0.000 0.286 0.6667 0.142 0.090 0.000 0.287 0.7000 0.143 0.095 0.000 0.289 0.7333 0.144 0.099 0.000 0.290 0.7667 0.144 0.104 0.000 0.292 0.8000 0.145 0.109 0.000 0.293 0.8333 0.146 0.114 0.000 0.295 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 7 0.8667 0.147 0.119 0.000 0.296 0.9000 0.147 0.124 0.000 0.298 0.9333 0.148 0.129 0.000 0.299 0.9667 0.149 0.134 0.000 0.301 1.0000 0.150 0.139 0.000 0.302 1.0333 0.150 0.144 0.000 0.304 1.0667 0.151 0.149 0.000 0.305 1.1000 0.152 0.154 0.000 0.307 1.1333 0.153 0.159 0.000 0.308 1.1667 0.153 0.164 0.000 0.310 1.2000 0.154 0.169 0.000 0.311 1.2333 0.155 0.174 0.000 0.313 1.2667 0.156 0.180 0.000 0.314 1.3000 0.156 0.185 0.000 0.316 1.3333 0.157 0.190 0.000 0.317 1.3667 0.158 0.195 0.000 0.319 1.4000 0.159 0.201 0.000 0.320 1.4333 0.159 0.206 0.000 0.322 1.4667 0.160 0.211 0.000 0.324 1.5000 0.161 0.217 0.000 0.325 1.5333 0.162 0.222 0.000 0.327 1.5667 0.163 0.227 0.000 0.328 1.6000 0.163 0.233 0.000 0.330 1.6333 0.164 0.238 0.000 0.331 1.6667 0.165 0.244 0.000 0.333 1.7000 0.166 0.249 0.000 0.334 1.7333 0.166 0.255 0.000 0.336 1.7667 0.167 0.260 0.000 0.338 1.8000 0.168 0.266 0.000 0.339 1.8333 0.169 0.272 0.000 0.341 1.8667 0.170 0.277 0.000 0.342 1.9000 0.170 0.283 0.000 0.344 1.9333 0.171 0.289 0.000 0.346 1.9667 0.172 0.294 0.000 0.347 2.0000 0.173 0.300 0.000 0.349 2.0333 0.174 0.306 0.096 0.350 2.0667 0.174 0.312 0.273 0.352 2.1000 0.175 0.318 0.502 0.354 2.1333 0.176 0.323 0.771 0.355 2.1667 0.177 0.329 1.074 0.357 2.2000 0.178 0.335 1.404 0.359 2.2333 0.178 0.341 1.756 0.360 2.2667 0.179 0.347 2.123 0.362 2.3000 0.180 0.353 2.501 0.363 2.3333 0.181 0.359 2.882 0.365 2.3667 0.182 0.365 3.261 0.367 2.4000 0.182 0.371 3.632 0.368 2.4333 0.183 0.378 3.988 0.370 2.4667 0.184 0.384 4.326 0.372 2.5000 0.185 0.390 4.639 0.373 2.5333 0.186 0.396 4.924 0.375 2.5667 0.187 0.402 5.178 0.377 2.6000 0.187 0.408 5.401 0.378 2.6333 0.188 0.415 5.592 0.380 2.6667 0.189 0.421 5.754 0.382 2.7000 0.190 0.427 5.892 0.383 2.7333 0.191 0.434 6.014 0.385 2.7667 0.192 0.440 6.205 0.387 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 8 2.8000 0.192 0.447 6.338 0.389 2.8333 0.193 0.453 6.469 0.390 2.8667 0.194 0.459 6.597 0.392 2.9000 0.195 0.466 6.723 0.394 2.9333 0.196 0.472 6.846 0.395 2.9667 0.197 0.479 6.967 0.397 3.0000 0.198 0.486 7.086 0.399 3.0333 0.198 0.492 7.203 0.401 21-000227 Basin 2 11/29/2021 1:28:22 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:2.53 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.1 Total Impervious Area:1.43 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.136371 5 year 0.2282 10 year 0.307226 25 year 0.431267 50 year 0.543557 100 year 0.674975 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1956 0.140 0.000 1957 0.303 0.000 1958 0.139 0.000 1959 0.128 0.000 1960 0.164 0.000 1961 0.124 0.000 1962 0.050 0.000 1963 0.355 0.000 1964 0.119 0.000 1965 0.139 0.000 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 10 1966 0.072 0.000 1967 0.175 0.000 1968 0.092 0.000 1969 0.067 0.000 1970 0.106 0.000 1971 0.142 0.000 1972 0.346 0.000 1973 0.117 0.000 1974 0.126 0.000 1975 0.105 0.000 1976 0.174 0.000 1977 0.056 0.000 1978 0.146 0.000 1979 0.105 0.000 1980 0.118 0.000 1981 0.485 0.000 1982 0.200 0.000 1983 0.206 0.000 1984 0.202 0.000 1985 0.063 0.000 1986 0.196 0.000 1987 0.189 0.000 1988 0.088 0.000 1989 0.348 0.000 1990 0.167 0.000 1991 1.052 0.000 1992 0.272 0.000 1993 0.169 0.000 1994 0.064 0.000 1995 0.170 0.000 1996 0.255 0.000 1997 0.122 0.000 1998 0.299 0.000 1999 0.154 0.000 2000 0.102 0.000 2001 0.107 0.000 2002 0.061 0.000 2003 0.123 0.000 2004 0.194 0.000 2005 0.093 0.000 2006 0.122 0.000 2007 0.141 0.000 2008 0.122 0.000 2009 0.207 0.000 2010 0.055 0.000 2011 0.081 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.0524 0.0000 2 0.4849 0.0000 3 0.3554 0.0000 4 0.3483 0.0000 5 0.3459 0.0000 6 0.3030 0.0000 7 0.2988 0.0000 8 0.2719 0.0000 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 11 9 0.2555 0.0000 10 0.2066 0.0000 11 0.2063 0.0000 12 0.2018 0.0000 13 0.2001 0.0000 14 0.1959 0.0000 15 0.1935 0.0000 16 0.1890 0.0000 17 0.1752 0.0000 18 0.1738 0.0000 19 0.1695 0.0000 20 0.1692 0.0000 21 0.1668 0.0000 22 0.1636 0.0000 23 0.1540 0.0000 24 0.1456 0.0000 25 0.1417 0.0000 26 0.1407 0.0000 27 0.1405 0.0000 28 0.1392 0.0000 29 0.1391 0.0000 30 0.1282 0.0000 31 0.1258 0.0000 32 0.1244 0.0000 33 0.1227 0.0000 34 0.1221 0.0000 35 0.1220 0.0000 36 0.1218 0.0000 37 0.1194 0.0000 38 0.1184 0.0000 39 0.1173 0.0000 40 0.1067 0.0000 41 0.1061 0.0000 42 0.1047 0.0000 43 0.1045 0.0000 44 0.1025 0.0000 45 0.0934 0.0000 46 0.0917 0.0000 47 0.0877 0.0000 48 0.0813 0.0000 49 0.0717 0.0000 50 0.0668 0.0000 51 0.0640 0.0000 52 0.0632 0.0000 53 0.0614 0.0000 54 0.0555 0.0000 55 0.0553 0.0000 56 0.0500 0.0000 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 12 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0682 14228 0 0 Pass 0.0730 12164 0 0 Pass 0.0778 9916 0 0 Pass 0.0826 8245 0 0 Pass 0.0874 6878 0 0 Pass 0.0922 5783 0 0 Pass 0.0970 5027 0 0 Pass 0.1018 4233 0 0 Pass 0.1066 3589 0 0 Pass 0.1114 3047 0 0 Pass 0.1162 2535 0 0 Pass 0.1210 2099 0 0 Pass 0.1258 1822 0 0 Pass 0.1306 1561 0 0 Pass 0.1354 1309 0 0 Pass 0.1402 1080 0 0 Pass 0.1450 937 0 0 Pass 0.1498 807 0 0 Pass 0.1546 689 0 0 Pass 0.1594 583 0 0 Pass 0.1642 472 0 0 Pass 0.1690 398 0 0 Pass 0.1738 340 0 0 Pass 0.1786 282 0 0 Pass 0.1834 245 0 0 Pass 0.1882 209 0 0 Pass 0.1930 167 0 0 Pass 0.1978 143 0 0 Pass 0.2026 123 0 0 Pass 0.2074 100 0 0 Pass 0.2122 85 0 0 Pass 0.2170 72 0 0 Pass 0.2218 60 0 0 Pass 0.2266 54 0 0 Pass 0.2314 49 0 0 Pass 0.2362 45 0 0 Pass 0.2410 39 0 0 Pass 0.2458 35 0 0 Pass 0.2507 24 0 0 Pass 0.2555 14 0 0 Pass 0.2603 13 0 0 Pass 0.2651 12 0 0 Pass 0.2699 12 0 0 Pass 0.2747 10 0 0 Pass 0.2795 10 0 0 Pass 0.2843 9 0 0 Pass 0.2891 9 0 0 Pass 0.2939 9 0 0 Pass 0.2987 9 0 0 Pass 0.3035 7 0 0 Pass 0.3083 7 0 0 Pass 0.3131 6 0 0 Pass 0.3179 6 0 0 Pass 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 13 0.3227 6 0 0 Pass 0.3275 6 0 0 Pass 0.3323 6 0 0 Pass 0.3371 6 0 0 Pass 0.3419 6 0 0 Pass 0.3467 5 0 0 Pass 0.3515 4 0 0 Pass 0.3563 3 0 0 Pass 0.3611 3 0 0 Pass 0.3659 3 0 0 Pass 0.3707 3 0 0 Pass 0.3755 3 0 0 Pass 0.3803 3 0 0 Pass 0.3851 3 0 0 Pass 0.3899 3 0 0 Pass 0.3947 3 0 0 Pass 0.3995 3 0 0 Pass 0.4043 3 0 0 Pass 0.4091 3 0 0 Pass 0.4139 3 0 0 Pass 0.4187 3 0 0 Pass 0.4235 3 0 0 Pass 0.4283 3 0 0 Pass 0.4331 3 0 0 Pass 0.4379 3 0 0 Pass 0.4427 3 0 0 Pass 0.4475 3 0 0 Pass 0.4523 3 0 0 Pass 0.4571 3 0 0 Pass 0.4619 3 0 0 Pass 0.4667 3 0 0 Pass 0.4715 3 0 0 Pass 0.4763 3 0 0 Pass 0.4811 3 0 0 Pass 0.4859 2 0 0 Pass 0.4907 2 0 0 Pass 0.4955 2 0 0 Pass 0.5003 2 0 0 Pass 0.5051 2 0 0 Pass 0.5099 2 0 0 Pass 0.5147 2 0 0 Pass 0.5195 2 0 0 Pass 0.5244 2 0 0 Pass 0.5292 2 0 0 Pass 0.5340 2 0 0 Pass 0.5388 2 0 0 Pass 0.5436 2 0 0 Pass 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 21-000227 Basin 2 11/29/2021 1:29:38 PM Page 15 LID Report 21-000227 Basin 2 11/29/2021 1:29:45 PM 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. 21-000227 Basin 2 11/29/2021 1:29:45 PM Page 17 Appendix Predeveloped Schematic 21-000227 Basin 2 11/29/2021 1:29:46 PM Page 18 Mitigated Schematic 21-000227 Basin 2 11/29/2021 1:29:47 PM Page 31 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. 2005-2021; 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 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 2 General Model Information Project Name:21-000227 Basin 1 Site Name: Site Address: City: Report Date:11/29/2021 Gage:Eaton Creek Data Start:1955/10/01 Data End:2011/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Pasture, Flat 4.4 Pervious Total 4.4 Impervious Land Use acre Impervious Total 0 Basin Total 4.4 Element Flows To: Surface Interflow Groundwater 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.75 Pervious Total 0.75 Impervious Land Use acre ROADS FLAT 1.46 ROOF TOPS FLAT 1.06 SIDEWALKS FLAT 1.13 Impervious Total 3.65 Basin Total 4.4 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 5 Routing Elements Predeveloped Routing 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 6 Mitigated Routing Trapezoidal Pond 1 Bottom Length:100.00 ft. Bottom Width:120.00 ft. Depth:3 ft. Volume at riser head:0.6138 acre-feet. Infiltration On Infiltration rate:2 Infiltration safety factor:1 Wetted surface area On Total Volume Infiltrated (ac-ft.):763.02 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):763.02 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Side slope 1:3 To 1 Side slope 2:3 To 1 Side slope 3:3 To 1 Side slope 4:3 To 1 Discharge Structure Riser Height:2 ft. Riser Diameter:18 in. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.275 0.000 0.000 0.000 0.0333 0.276 0.009 0.000 0.557 0.0667 0.277 0.018 0.000 0.559 0.1000 0.278 0.027 0.000 0.561 0.1333 0.279 0.037 0.000 0.563 0.1667 0.280 0.046 0.000 0.565 0.2000 0.281 0.055 0.000 0.567 0.2333 0.282 0.065 0.000 0.569 0.2667 0.283 0.074 0.000 0.572 0.3000 0.284 0.084 0.000 0.574 0.3333 0.285 0.093 0.000 0.576 0.3667 0.286 0.103 0.000 0.578 0.4000 0.287 0.112 0.000 0.580 0.4333 0.288 0.122 0.000 0.582 0.4667 0.289 0.131 0.000 0.584 0.5000 0.290 0.141 0.000 0.586 0.5333 0.291 0.151 0.000 0.588 0.5667 0.292 0.161 0.000 0.590 0.6000 0.294 0.170 0.000 0.592 0.6333 0.295 0.180 0.000 0.594 0.6667 0.296 0.190 0.000 0.597 0.7000 0.297 0.200 0.000 0.599 0.7333 0.298 0.210 0.000 0.601 0.7667 0.299 0.220 0.000 0.603 0.8000 0.300 0.230 0.000 0.605 0.8333 0.301 0.240 0.000 0.607 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 7 0.8667 0.302 0.250 0.000 0.609 0.9000 0.303 0.260 0.000 0.611 0.9333 0.304 0.270 0.000 0.614 0.9667 0.305 0.280 0.000 0.616 1.0000 0.306 0.290 0.000 0.618 1.0333 0.307 0.301 0.000 0.620 1.0667 0.308 0.311 0.000 0.622 1.1000 0.309 0.321 0.000 0.624 1.1333 0.310 0.332 0.000 0.627 1.1667 0.312 0.342 0.000 0.629 1.2000 0.313 0.352 0.000 0.631 1.2333 0.314 0.363 0.000 0.633 1.2667 0.315 0.373 0.000 0.635 1.3000 0.316 0.384 0.000 0.637 1.3333 0.317 0.394 0.000 0.640 1.3667 0.318 0.405 0.000 0.642 1.4000 0.319 0.416 0.000 0.644 1.4333 0.320 0.426 0.000 0.646 1.4667 0.321 0.437 0.000 0.648 1.5000 0.322 0.448 0.000 0.651 1.5333 0.323 0.459 0.000 0.653 1.5667 0.325 0.469 0.000 0.655 1.6000 0.326 0.480 0.000 0.657 1.6333 0.327 0.491 0.000 0.659 1.6667 0.328 0.502 0.000 0.662 1.7000 0.329 0.513 0.000 0.664 1.7333 0.330 0.524 0.000 0.666 1.7667 0.331 0.535 0.000 0.668 1.8000 0.332 0.546 0.000 0.671 1.8333 0.333 0.557 0.000 0.673 1.8667 0.334 0.568 0.000 0.675 1.9000 0.336 0.580 0.000 0.677 1.9333 0.337 0.591 0.000 0.679 1.9667 0.338 0.602 0.000 0.682 2.0000 0.339 0.613 0.000 0.684 2.0333 0.340 0.625 0.096 0.686 2.0667 0.341 0.636 0.273 0.689 2.1000 0.342 0.647 0.502 0.691 2.1333 0.343 0.659 0.771 0.693 2.1667 0.345 0.670 1.074 0.695 2.2000 0.346 0.682 1.404 0.698 2.2333 0.347 0.693 1.756 0.700 2.2667 0.348 0.705 2.123 0.702 2.3000 0.349 0.717 2.501 0.704 2.3333 0.350 0.728 2.882 0.707 2.3667 0.351 0.740 3.261 0.709 2.4000 0.353 0.752 3.632 0.711 2.4333 0.354 0.764 3.988 0.714 2.4667 0.355 0.775 4.326 0.716 2.5000 0.356 0.787 4.639 0.718 2.5333 0.357 0.799 4.924 0.721 2.5667 0.358 0.811 5.178 0.723 2.6000 0.359 0.823 5.401 0.725 2.6333 0.361 0.835 5.592 0.728 2.6667 0.362 0.847 5.754 0.730 2.7000 0.363 0.859 5.892 0.732 2.7333 0.364 0.871 6.014 0.735 2.7667 0.365 0.884 6.205 0.737 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 8 2.8000 0.366 0.896 6.338 0.739 2.8333 0.368 0.908 6.469 0.742 2.8667 0.369 0.920 6.597 0.744 2.9000 0.370 0.933 6.723 0.746 2.9333 0.371 0.945 6.846 0.749 2.9667 0.372 0.957 6.967 0.751 3.0000 0.373 0.970 7.086 0.753 3.0333 0.375 0.982 7.203 0.756 21-000227 Basin 1 11/29/2021 1:34:52 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.4 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.75 Total Impervious Area:3.65 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.237167 5 year 0.396869 10 year 0.534306 25 year 0.750029 50 year 0.945317 100 year 1.17387 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1956 0.244 0.000 1957 0.527 0.000 1958 0.242 0.000 1959 0.223 0.000 1960 0.284 0.000 1961 0.216 0.000 1962 0.087 0.000 1963 0.618 0.000 1964 0.208 0.000 1965 0.242 0.000 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 10 1966 0.125 0.000 1967 0.305 0.000 1968 0.159 0.000 1969 0.116 0.000 1970 0.184 0.000 1971 0.246 0.000 1972 0.602 0.000 1973 0.204 0.000 1974 0.219 0.000 1975 0.182 0.000 1976 0.302 0.000 1977 0.097 0.000 1978 0.253 0.000 1979 0.182 0.000 1980 0.206 0.000 1981 0.843 0.000 1982 0.348 0.000 1983 0.359 0.000 1984 0.351 0.000 1985 0.110 0.000 1986 0.341 0.000 1987 0.329 0.000 1988 0.153 0.000 1989 0.606 0.000 1990 0.290 0.000 1991 1.830 0.000 1992 0.473 0.000 1993 0.294 0.000 1994 0.111 0.000 1995 0.295 0.000 1996 0.444 0.000 1997 0.212 0.000 1998 0.520 0.000 1999 0.268 0.000 2000 0.178 0.000 2001 0.186 0.000 2002 0.107 0.000 2003 0.213 0.000 2004 0.337 0.000 2005 0.162 0.000 2006 0.212 0.000 2007 0.245 0.000 2008 0.212 0.000 2009 0.359 0.000 2010 0.096 0.000 2011 0.141 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.8302 0.0000 2 0.8433 0.0000 3 0.6181 0.0000 4 0.6058 0.0000 5 0.6016 0.0000 6 0.5269 0.0000 7 0.5196 0.0000 8 0.4729 0.0000 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 11 9 0.4443 0.0000 10 0.3594 0.0000 11 0.3588 0.0000 12 0.3510 0.0000 13 0.3479 0.0000 14 0.3406 0.0000 15 0.3366 0.0000 16 0.3288 0.0000 17 0.3046 0.0000 18 0.3022 0.0000 19 0.2948 0.0000 20 0.2942 0.0000 21 0.2900 0.0000 22 0.2845 0.0000 23 0.2679 0.0000 24 0.2532 0.0000 25 0.2464 0.0000 26 0.2447 0.0000 27 0.2443 0.0000 28 0.2420 0.0000 29 0.2420 0.0000 30 0.2230 0.0000 31 0.2188 0.0000 32 0.2164 0.0000 33 0.2134 0.0000 34 0.2123 0.0000 35 0.2121 0.0000 36 0.2119 0.0000 37 0.2076 0.0000 38 0.2060 0.0000 39 0.2041 0.0000 40 0.1855 0.0000 41 0.1845 0.0000 42 0.1820 0.0000 43 0.1818 0.0000 44 0.1783 0.0000 45 0.1624 0.0000 46 0.1595 0.0000 47 0.1525 0.0000 48 0.1414 0.0000 49 0.1247 0.0000 50 0.1161 0.0000 51 0.1113 0.0000 52 0.1098 0.0000 53 0.1068 0.0000 54 0.0966 0.0000 55 0.0962 0.0000 56 0.0869 0.0000 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 12 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.1186 14320 0 0 Pass 0.1269 11937 0 0 Pass 0.1353 9682 0 0 Pass 0.1436 8182 0 0 Pass 0.1520 6922 0 0 Pass 0.1603 5783 0 0 Pass 0.1687 4929 0 0 Pass 0.1770 4124 0 0 Pass 0.1854 3540 0 0 Pass 0.1937 3047 0 0 Pass 0.2021 2519 0 0 Pass 0.2104 2125 0 0 Pass 0.2188 1800 0 0 Pass 0.2271 1536 0 0 Pass 0.2355 1301 0 0 Pass 0.2438 1089 0 0 Pass 0.2522 938 0 0 Pass 0.2605 793 0 0 Pass 0.2689 687 0 0 Pass 0.2772 577 0 0 Pass 0.2856 474 0 0 Pass 0.2940 409 0 0 Pass 0.3023 331 0 0 Pass 0.3107 279 0 0 Pass 0.3190 243 0 0 Pass 0.3274 209 0 0 Pass 0.3357 172 0 0 Pass 0.3441 140 0 0 Pass 0.3524 122 0 0 Pass 0.3608 100 0 0 Pass 0.3691 85 0 0 Pass 0.3775 73 0 0 Pass 0.3858 60 0 0 Pass 0.3942 54 0 0 Pass 0.4025 49 0 0 Pass 0.4109 45 0 0 Pass 0.4192 39 0 0 Pass 0.4276 34 0 0 Pass 0.4359 23 0 0 Pass 0.4443 14 0 0 Pass 0.4526 13 0 0 Pass 0.4610 12 0 0 Pass 0.4693 12 0 0 Pass 0.4777 10 0 0 Pass 0.4860 10 0 0 Pass 0.4944 9 0 0 Pass 0.5027 9 0 0 Pass 0.5111 9 0 0 Pass 0.5194 9 0 0 Pass 0.5278 7 0 0 Pass 0.5361 7 0 0 Pass 0.5445 6 0 0 Pass 0.5528 6 0 0 Pass 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 13 0.5612 6 0 0 Pass 0.5695 6 0 0 Pass 0.5779 6 0 0 Pass 0.5862 6 0 0 Pass 0.5946 6 0 0 Pass 0.6029 5 0 0 Pass 0.6113 4 0 0 Pass 0.6196 3 0 0 Pass 0.6280 3 0 0 Pass 0.6363 3 0 0 Pass 0.6447 3 0 0 Pass 0.6530 3 0 0 Pass 0.6614 3 0 0 Pass 0.6697 3 0 0 Pass 0.6781 3 0 0 Pass 0.6864 3 0 0 Pass 0.6948 3 0 0 Pass 0.7031 3 0 0 Pass 0.7115 3 0 0 Pass 0.7198 3 0 0 Pass 0.7282 3 0 0 Pass 0.7365 3 0 0 Pass 0.7449 3 0 0 Pass 0.7532 3 0 0 Pass 0.7616 3 0 0 Pass 0.7699 3 0 0 Pass 0.7783 3 0 0 Pass 0.7867 3 0 0 Pass 0.7950 3 0 0 Pass 0.8034 3 0 0 Pass 0.8117 3 0 0 Pass 0.8201 3 0 0 Pass 0.8284 3 0 0 Pass 0.8368 3 0 0 Pass 0.8451 2 0 0 Pass 0.8535 2 0 0 Pass 0.8618 2 0 0 Pass 0.8702 2 0 0 Pass 0.8785 2 0 0 Pass 0.8869 2 0 0 Pass 0.8952 2 0 0 Pass 0.9036 2 0 0 Pass 0.9119 2 0 0 Pass 0.9203 2 0 0 Pass 0.9286 2 0 0 Pass 0.9370 2 0 0 Pass 0.9453 2 0 0 Pass 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 21-000227 Basin 1 11/29/2021 1:35:34 PM Page 15 LID Report 21-000227 Basin 1 11/29/2021 1:35:42 PM 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. 21-000227 Basin 1 11/29/2021 1:35:42 PM Page 17 Appendix Predeveloped Schematic 21-000227 Basin 1 11/29/2021 1:35:42 PM Page 18 Mitigated Schematic 21-000227 Basin 1 11/29/2021 1:35:43 PM Page 31 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. 2005-2021; 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