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Home My WebLink AboutStormwater and Erosion /Sediment Control with Revisions for COM2003-00197 - PLN General - 11/21/2003 c o `) STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for SITE REDEVELOPMENT for Reid Realty Site Location: 23861 NE State Route 3, Belfair, WA 98528 Section 29, T23 N, Rl W, W.M., Belfair, Mason County, WA Prepared for: Alan Cady, et al Contact Person: Alan Cady 9939 Mickelberry Road NW Silverdale, WA 98383 (360) 692-6102 Prepared by: MARLEY L. YOUNG, CONSULTING ENGINEER P.O. Box 1343 Shelton,WA 98584 (360) 426-7475 Project No. 2003-19 November 21,2003 MARLEY L. YOUNG, CONSULTING ENGINEER P.O. BOX 1343, SHELTON, WA 98584-0959 Civi I Engineering (360)426-7475-(360)490-0939-Fax(360)426-5789 ' StorrnHater Site Plans Marley L. Young, P.E., P.L.S. Sewer Extensions Civil Engineer& Land Surveyor O o IIIIIIII) PROJECT ENGINEER'S CERTIFICATION I hereby certify that this Stormwater and Erosion/Sediment Control Site Plan prepared for Alan Cady, et al,has been prepared by me or under my supervision and meets minimum standards of Mason County and normal standards of engineering practice. I understand that the jurisdiction does not and will not assume liability for the sufficiency, suitability,\ or performance of drainage facilities designed by me. �PQ WA y 2 Marley L. Young,P.E.,P.L.S. 0 pe► ,p 14144IsTf �4r eP`�S�oNA E)MI S 3/5/9 Marley L Young,Consulting Engineer Project No.2003-19 1 STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for Alan Cady,et al—Reid Realty Site Redevelopment,Belfair,Washington The Puget Sound Water Quality Management Plan(PSWQMP),which is administered by the State of Washington Department of Ecology,mandates that all counties and cities within the Puget Sound drainage basin adopt ordinances to control runoff from new development and redevelopments. The PSWQMP also directs local governments to adopt stormwater programs that must include minimum requirements that are consistent with the PSWQMP, and which are substantially equivalent t the DOE's Stormwater Management Manual for the Puget Sound Basin,(DOE's Technical Manual). The goal of the Puget Sound Water Quality Management Plan is to: ■ Protect and restore beneficial uses of aquatic resources, including shellfish beds,fish habitat,and other resources; ■ Prevent contamination of sediments from urban runoff; ■ Meet standards for water and sediment quality by reducing pollutant discharges from stormwater throughout Puget Sound. BEST MANAGEMENT PRACTICES(BMPs) Best management practices(BMPs)are defined as physical, structural, or management practices that, when used singly or in combination,prevent or reduce pollution of water. Specific BMPs have been developed by Ecology to control stormwater runoff(quality and quantity)for protection of receiving waters. There are three main reasons for applying BMPs before considering advanced treatment. First, it has been shown through research and experience that BMPs can significantly reduce pollutants in stormwater. Using BMPs to control localized discharges is cost effective in comparison to treating large volumes of water. Second, our lakes and streams depend on stormwater to provide adequate flow for fish habitat and water quality. Our groundwater resources also depend on stormwater for recharge. BMP implementation offers a way to discharge water back into the natural system. Third,and perhaps most important, stormwater management programs demand the conscientious use of best management practices to protect water quality. Specific BMPs that cover stormwater runoff quality and quantity have been included in Ecology's Technical Manual. Those BMPs can be divided into three basic categories, including Source Control BMPs, Runoff Treatment BMPs and Streambank Erosion Control BMPs. Source Control BMPs are designed to prevent pollutants from entering stormwater by eliminating the source of pollution or by preventing contact of pollutants with rainfall and runoff. Source controls are usually the most cost-effective because they reduce or eliminate the need for treatment BMPs. Implementing source control BMPs generally involves relatively simple and straightforward actions. Examples of source control BMPs include erosion control(e.g.,covering disturbed soil),covering material storage areas,and eliminating illicit discharges. Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment Runoff Treatment BMPs are designed to remove pollutants contained in stormwater runoff. These types of BMPs are the second line of defense in protecting stormwater quality. Examples of runoff treatment BMPs include infiltrated basins,bioswales and sediment ponds. Streambank Erosion Control BMPs are designed to protect stream ecosystems from erosion and sedimentation. Types of streambank erosion control BMPs include flow attenuation BMPs for reducing peak flows from a development(e.g.,detention ponds, infiltration trenches),and streamside stabilization BMPs used to stabilize eroding streambanks. I. PROJECT OVERVIEW PROPOSED PROJECT DESCRIPTION: The proposal is a redevelopment of an existing commercial building site. The existing building will eventually be razed. There will be an increase in asphalt parking. Stormwater will be disposed of by onsite infiltration. LEGAL DESCRIPTION The site is within the NE '/4 of the SE '/4 of Section 29,Township 23 North,Range 1 West, W.M., Belfair, Mason County, Washington. EXISTING CONDITIONS: The Reid Realty,Inc.,building is located on property owned by the Cady family. The property has been business-oriented for at least twenty-five years. In listening to the owners of the property,they have told me that there is no stormwater sewer system/ditch system that would carry the surface water away from the property. They have also indicated all rainwater infiltrates on site and this onsite infiltration has been the method of natural stormwater disposal for the past twenty-five years,and the owners wish to continue with this preferred method of stormwater disposal. The way the total property is contoured,they do not receive stormwater from offsite sources. A good percentage of the lot consists of existing asphalt parking There are no trees on the property. g p g g p p g and gravel parking. GENERAL LOCATION: Reid Realty, Inc., site address is 23832 State Highway 3, Belfair, WA 98528. The site is on State Highway 3,north of the Old Belfair Highway. STORMWATER AND EROSION/SEDIMENT CONTROL PLAN REQUIREMENT DETERMINATION: Projects that add 5,000 square feet or more of new impervious surface must comply with all the large Parcel minimum Requirements. A Large Parcel Erosion and Sediment Control Plan is discussed,and the necessary BMPs are included in this report. The report will review the components of the Large Parcel Stormwater Site Plan,which include the temporary erosion and sediment control necessary during construction, permanent stormwater quantity control, civil drawings and specifications,and operation and maintenance recommendations for the needed stormwater facilities. This project will comply with the following Large Parcel minimum Requirements#1 through#I I found in Section I-2.5 of the Department of Ecology' Stormwater Management Manual for the Puget Sound Basin(the Technical manual). Minimum Requirement#1: EROSION AND SEDIMENT CONTROL See Section IX, Erosion and Sediment Control Plan (Requirements#1415). 2 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment Minimum Requirement#2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS Natural drainage patterns shall be maintained,and discharges from the site shall occur at the natural location,to the maximum extent practicable. No surface water drainage flows through this project. Minimum Requirement#3: SOURCE CONTROL OF POLLUTION Where necessary to prevent the migration of silt during construction, the owner/contractor shall construct channels to keep overland flows away from the area under construction. If dust becomes a problem, dust control methods using water shall be employed.. If necessary to reduce tracking of mud and debris onto paved roads, the owner/contractor shall utilize a construction entrance rock pad. If required, migration-sensitive soils shall be covered with straw mulch or black plastic to prevent off-site migration of soil. The erosion control plan consists of installing a construction entrance, a sediment trap and filter fabric fence. Minimum Requirement#4: RUNOFF TREATMENT BMPS Grass swale will be used as the method of treatment. Minimum Requirement#5: STREAMBANK EROSION CONTROL NA—Because total infiltration is on site. Minimum Requirement#6: WETLANDS NA—The site does not include wetlands. Minimum Requirement#7: WATER QUALITY SENSITIVE AREAS NA Minimum Requirement#8: OFF-SITE ANALYSIS AND MITIGATION NA— Total infiltration onsite; therefore, offsite analysis is not required. Minimum Requirement#9: BASIN PLANNING An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. NA—No basin plan has been established at this location. Minimum Requirement#10: OPERATION AND MAINTENANCE An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs, and the party(or parties)responsible for maintenance shall be identified. The owner is responsible for operation and maintenance of the stormwater facilities. A "Declaration of Covenants Associated With Privately Maintained Storm Drainage Facilities", which must be recorded and submitted to Mason County as part of the approval process, has been prepared for the project. A copy of the unsigned document is included in the Attachments. Minimum Requirement#11: FINANCIAL LIABILITY Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. NA—Mason County has not indicated that a financial instrument will be required. 3 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment II. PLOT PLAN Engineer's Civil Drawings have been developed for the project showing the location of the improvements and the layout of the proposed Permanent Stormwater Control BMPs, and an Erosion/Sediment Control Plan to be used during construction. By reference these drawings are made apart of this report. III. PRELIMINARY CONDITIONS SUMMARY See Section I, Project Overview. IV. OFF-SITE ANALYSIS (No off-site analysis is required. See Min. Req. #8 above.) Wetlands or Water of the State This site does not contain wetlands and is not within 200 feet of any waters of the State. Analysis of the 100-year Flood This site does not contain or abut a Federal Emergency Management Administration(FEMA)identified stream and is,therefore,outside any 100-year flood plain. V. PERMANENT STORMWATER QUALITY CONTROL PLAN All storm events are collected and directed to the retention pond through a grass swale. Emergency spill containment and control has been explained above. STORM EVENT DESIGN ASSUMPTIONS Based on DOE's Stormwater Management Manual: STORM EVENT The stormwater program Water Works(software for hydrology by Engenious Systems, Inc.)was used to model the storm flows,retention, infiltration and releases. Rain Precipitation(in.) Six-month, 24-hour Storm Event 2.24 (6-mo. @ 64%of 2-yr.) Two-year,24-hour Storm Event 3.50 Ten-year, 24-hours Storm Event 4.75 Hundred-year, 24-hour Storm Event 6.75 Rainfall choice IA Hydrograph SBUH** ** Santa Barbara Urban Hydrograph method DRAINAGE BASIN Indianola sandy loam(Id),0-5 percent slopes Hydrologic Soil Group A Infiltration Rate for Pond 6.00 min./inch CN# for Impervious 98 CN#for Pervious—Landscaping/Undeveloped 85 NOTE: Given the Storm Event, Soil Type and Land Use,the Runoff Curve Number(CN#) is an indicator of the total surface and subsurface runoff. 4 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment POST DEVELOPMENT STORMWATER RUNOFF for 1.24 ACRES Storm Event 6-month Two-year Ten-year 100-year Post Flow cfs 0.390 0.713 1.046 1.586 Post volume ac ft 0.147 0.264 0.385 0.583 INFILTRATION-RETENTION POND Floor Length ft 65 Floor Width ft 20 Side Slopes: 3H to IV Infiltration Rate min./inch 6 TOTAL INFILTRATION Storm Event 6-month Two-year Ten-year 100-year Post Flow cfs 0.00 0.00 0.00 000 Post Depth ft 0.11 0.52 1.04 1.93 SEDIMENT TRAP Using proposed completed conditions to calculate runoff capacity requirements. Volume capacity 1,947 cf with a depth of 1.45 feet. BIOSWALE Floor length: ft 85 Floor width: ft 3 Maximum Bioswale Slope: 2% Side Slopes: 3H to IV Cubic Feet Per Second: 6 mo. =0.39 cfs; 100-yr.= 1.59 cfs Manning's Roughness Coefficient(n)6-mo. (n)=0.06; 100-yr. (n)=0.06 Velocity in Bioswale: 6-mo. = 1.16 fps; 100-yr. = 1.80 fps Min. Water Depth: 6-mo. =0.19 ft; 100-yr. =0.37 ft. Min. Bioswale Depth: 0.74 ft. (double the 100-yr.water depth) Refer to Supporting Calculations for further details. VI. SPECIAL REPORTS AND STUDIES Geotechnical analysis of infiltration VII. BASIN AND COMMUNITY PLANNING NA VII. PERMITS Agency Permit/Approval Mason County Grading Permit IX. EROSION and SEDIMENT CONTROL PLAN Temporary Erosion Control This project includes temporary erosion control. See Civil Drawings. The disturbance to the property is minimal. The types of soils are sandy, gravelly, and do not lend themselves to migration. 5 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment Erosion control will use silt fences, temporary sediment pond, and the stabilization of the construction entrance. Project Description/Existing Site Conditions Refer to Section I, Project Overview. Adjacent Areas Impacts NA —No impact anticipated SCS Soils Description The Soil conservation Service—Soil Survey of Mason County Series 1951,No. 9,Issued September 1069, shows this property having soils type Indianola sandy loam(1d),0-5 percent slopes. Soils conditions found on the property may not match exactly the soils described by SCS. Critical Areas No critical areas have been identified on this site. Erosion and Sediment Control Measures Minimum Requirements Mason County has adopted the Department of Ecology"Stormwater Management Manual for the Puget Sound Basin. All projects that disturb more than one acre must develop a Permanent Stormwater Quality Control Plan. (Mason County Ordinance 141-97) EROSION AND SEDIMENT CONTROL REQUIREMENTS The existing soils on the site have been classified by the SCS as Indianola sandy loam(Id), 0-5 percent slopes. I feel that the erosion and sediment control system hereinafter proposed will adequately provide the necessary erosion and sediment protection. The fifteen large parcel minimum requirements specified by DOE are: #1: Stabilization and Sediment Trapping All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30,no exposed and unworked soils shall remain unstabilized for more than 2 days. From May 1 to September 30,no exposed and unworked soils shall remain unstabilized for more than 7 days. Prior to leaving the site, stormwater runoff shall pass through a sediment pond or sediment trap, or other appropriate BMPs. #2: Delineate Clearing and Easement Limits The clearing limits shall be defined by the owner. #3: Protection of Adjacent Properties The underlying soils have very little potential for migration. Protecting adjacent property from damage from sediment deposition does not appear to be a problem. #4: Timing and Stabilization of Sediment Trapping Measures Sediment trap and filter fabric will be placed as shown on the Civil Drawings. #5: Cut and Fill Slopes The infiltration pond shall have side slopes no steeper than 3 feet horizontal to 1 foot vertical(3:1). Other minor side slopes will be 2 or 3:1. 6 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et a]—Belfair Site Redevelopment #6: Controlling Off-site Erosion Off-site erosion is not anticipated to become an issue. #7: Stabilization of Temporary Conveyance Channels and Outlets It is anticipated that the water velocity for ground surface flows will not reach erosion velocity. All stormwater will be infiltrated on site. #8: Storm Drain Inlet Protection See Civil Drawings for storm drain inlet protection. #9: Underground Utility Construction Architectural and Civil drawings put contractor on notice as to the installation requirements of underground utilities. #10: Construction Access Routes Construction vehicles access shall be,whenever possible,limited to one route. Access points shall be stabilized to minimize the tracking of sediment onto public roads. There shall be only one access to the site for construction purposes. See Civil Drawings for location and detail. #11: Removal of Temporary BMPs All temporary erosion and sediment control BMPs will be removed when final site stabilization is achieved. #12: Dewatering Construction Sites Dewatering is not necessary. The soil characteristic is highly porous. #13: Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediments that occur onsite during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14: Maintenance All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. #15: Financial Liability Not Applicable to this project. Permanent Stabilization At the conclusion of site construction improvements,within seven days permanent site stabilization shall be completed by spreading seed and mulch on all exposed soils to establish a ground cover. Use the following recommended seed mixture for erosion control,or a County-approved alternate seed mixture. Proportions Percent Percent Name by Weight Puri Germination Redtop(Ag[ostis alba) 10 percent 92 90 Annual rye(Lolium multiflorum) 40 percent 98 90 Chewing fescue 40 percent 97 80 (Festuca rubra commutata) 7 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al-Belfair Site Redevelopment (Jamestown,Banner,Shodow,or Koket) White dutch clover(Trifolium repens) 10 percent 96 90 The following is a guide for use of recommended mulch material: Application Rates Depth Mulch Quality Per 1000 Per of Material Standards Sq.Feet Acre Application Remarks Gravel,Crushed Washed'/.to 9 CY 3 inches Good for short slope and Stone 1'/2-inch around woody plants and ornaments. Use where Subject to foot traffic. Hay or straw Air dry.Free from 75-100 lbs 1.5 to Min.2 inches Use where needed for more weed seed and pounds 2.5 tons than 3 mos. Subject to coarse material. (Approx. blowing—keep moist or 2 in.thick) 90-120 Bales When used on critical areas, Wood Fiber No growth organism 25 to 30 1000 to 1500 double application rate. Cellulose(Partly inhibiting factors pounds pounds Apply with hydromulcher. Digested wood factors. No tie-down required. fibers) Stormwater Management Considerations Please see Section V, "Permanent Stormwater Quality Control Plan"for a complete description of the stormwater management plan. Maintenance The responsibility for maintaining the facilities will lie with the owners of the property or their assigns. For maintenance recommendations please see Section XI, "Operation and Maintenance Manual"below. Calculations Calculations are briefly described in Section V, "Permanent Stormwater Quality Control Plan"above, and included in the attached Supporting Calculations. X. BOND QUANTITIES WORKSHEET,RETENTION/DETENTION FACILITY SUMMARY SHEET AND SKETCH,AND DECLARATION OF COVENANT Bond Quantities Worksheet-NA Retention/Detention Facility Summary sheet-NA Declaration of Covenant—Mason County requires that a "Declaration of Covenants Associated with Privately Maintained Storm Drainage Facilities"be executed and filed with Mason County as part of the approval process. A copy of the unsigned document is included in the Attachments. XI. OPERATION& MAINTENANCE MANUAL MAINTENANCE PLAN The responsibility for maintaining the facilities will lie with the owners of the property or their assigns (e.g.,Contractor). The facilities are designed to minimize the need for extensive maintenance. MAINTENANCE OF TEMPORARY EROSION BMPs DURING CONSTRUCTION During construction the major maintenance activity is to inspect the silt fences and sediment pond. If the drainage carries mud or debris,additional silt fences should be placed in the path of the drainage to eliminate any siltation from exiting the project site. 8 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belf tir Site Redevelopment All erosion and sediment control BMPs installed shall be inspected regularly,especially after any large storm. Maintenance, including removal and proper disposal of sediment should be done as necessary. (Generally sediment that restricts the sheet flow or infiltration must be removed.) MAINTENANCE OF PERMANENT STORMWATER CONTROL FACILITIES The Type 30 catch basin shall be inspected semi-yearly for the accumulation of oil and sediment. The catch basin should be cleaned with oil-absorbing materials every six months,spring and fall, if warranted. In the fall inspect the grass swale to assure that the grass will stand 4-5 inches through winter. Inspect the Swale to assure that it is clear of debris that would block flow and that the flow is spread throughout the width of the swale. In the spring the swale shall be inspected for black or brown discoloration or staining caused by fluids. The stained soil and sod should be replaced and the old material disposed of in the appropriate manner. If the infiltration retention pond has an accumulation of silt that would restrict the infiltration rate,the silt must be removed. The infiltration pond shall also be kept clean of all settleable solids and floating debris. Ideal condition is that stormwater in the pond would disappear(infiltrate)within 24 hours of a 2-year storm event. CHANGED CONDITIONS: The conclusions and recommendations in this report are based on my interpretation of site conditions,and the expectation that my onsite exploratory efforts adequately define the surface and sub-surface conditions throughout the site. In the event that the scope of the project or location of the improvements or surface/subsurface conditions differ from those I relied on in this report,I should be advised. At that time,a review of the changed conditions will be made and alternative or remedial recommendations given as requested. L. p This Stormwater Site Plan has been prepared by: oF NLn 10 IST Marley L. Yo g P. .L.S. ��14144 HAt IXPiF.�S 3/5/O 9 Marley L.Young,Consulting Engineer Project No.2003-19 l Alan Cady,et al—Belfair Site Redevelopment ATTACHMENTS Marley L.Young,Consulting Engineer Project No.2M3-19 FROM : GEOTESTLRB rNUNE NU. . JbI6(J44040 IVUV. 1J GEOTECHNICAL TESTING LABORATORY MARLEY YOUNG CONSULTING ENGINEER P. O. Box 1343 SHELTON,WA 98584 Re: Perc.testing for infiltration pond Reid Realty,Belfair,WA Gentlemen.- Three pere holes were dug for infiltration testing on Nov. 7, 2003 for the above referenced project. The soil infiltration classification was Type A The pert rate for Hole 92, in the area where the proposed swale is to be located was 1.2 minutes per inch. Thank you for this opportunity to be of service to you. If you have any questions concerning the test results, the procedures used, or if we can be of any further assistance please call on us at (360)754-4612. Respectfully Submitted, GKOTECfINiCAL TESTING LABORATORY Harold Parks, Engineering Geologist lool l Blomberg Street SW,Olympia,WA 98512 Phone#: (360)754-4612 Fax#:(360)754-4848 1 Alan Cady,et al—Belfair Site Redevelopment DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES (Copy of unsigned document) Marley L.Young,Consulting Engineer Project No.2003-19 i RETURN ADDRESS GRANTOR(S)(Last,First and Middle Initial) GRANTEE: MASON COUNTY DEPARTMENT OF PUBLIC WORKS DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES Declaration of Covenant In consideration of approval of the development known as ,relating to real property legally described as follows: County Assessor's Property Tax Parcel Number The undersigned,as owner(s),covenant and agree that: 1. If at any time Mason County reasonably determines that maintenance or repair work is required to be done to the existing,approved storm drainage facilities installed on the property described above and located outside of any public right of way(which will mean repair and/or clean out of the existing system only to the same standards as originally installed and approved),the Director of the Department of Public Works shall give the current owners seven days notice that the County intends to perform such maintenance or repairs,or to have them performed by others. If the current owners have not completed or are not diligently pursuing the repair or maintenance of the system and it becomes necessary for Mason County to perform the work,the current owners will assume responsibility for the cost of such maintenance or repair and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments,and any costs or fees incurred by the County,should any legal action be required to collect such payments,will be borne by the parties responsible for said reimbursements. 2. If at any time Mason County reasonably determines that the existing and approved storm drainage system on the property poses a hazard to life and limb,or endangers property,or adversely affects the safety and operations of a public way,due to failure,damage or non-maintenance of the existing on-site storm system,and that the situation is so adverse as to preclude written notice to said owners,the Director of the Department of Public Works may take the measures necessary to eliminate the hazardous situation (which will mean repair or clean out of the existing system only to the same standards as originally installed and approved)provided the Director has first made a reasonable effort to locate said owner before These covenants are intended to protect the value and desirability of the real property described above,and to benefit all the citizens of Mason County. They shall run with the land and be binding on all parties having or acquiring from the current owners or their successors,any right,title or interest therein, and to the benefit of all the citizens of Mason County. h'. Signature Signature Owner Owner Address Address City, State,Zip City, State, Zip Phone: Phone: STATE OF WASHINGTON, ss. (INDIVIDUAL ACKNOWLEDGMENT) County of MASON Notary Public in and for the State of Washington, residing at I, o ry gt g do hereby certify that on this day of ,200_, personally appeared before me to me known to be the individual described in and who executed the within instrument and acknowledged that signed and sealed the same as free and voluntary act and deed for the uses and purposes herein mentioned. GIVEN UNDER MY HAND AND OFFICIAL SEAL this day of , 200_. Notary Public in and for the State of Washington, residing at in said County. My Commission expires Alan Cady,et al—Belfair Site Redevelopment SUPPORTING CALCULATIONS Marley L.Young,Consulting Engineer Project No.2003-19 I 11/21/03 3 : 2 : 10 pm Marley Young Engineer page 1 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 BASIN SUMMARY BASIN ID: a NAME: 1/2 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: PERV0 . 00 cfs IMP RAINFALL TYPE. . . . : TYPEIA PRECIPITATION. . . . : 2 . 24 inches AREA. . : 0 .69 Acres 0 . 55 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks : 27 . 00 s : 0 . 0400 PEAK RATE : 0 . 39 cfs VOL: 0 . 15 Ac-ft TIME : 480 min BASIN ID: b NAME: 2 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: PERV0 . 00 cfs IMP RAINFALL TYPE. . . . : TYPEIA PRECIPITATION. . . . : 3 .50 inches AREA. . : 0 . 69 Acres 98 . 00 0 . 55 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 VOL: 0 . 26 Ac-ft TIME: 480 min PEAK RATE. 0 . 71 cfs O BASIN ID: c NAME: 10 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 24 Acres BASEFLOWS: PERV0 . 00 cfs IMP RAINFALL TYPE. . . . : TYPEIA PRECIPITATION. . . . : 4 . 75 inches AREA. . : 0 . 69 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 1 . 05 cfs VOL: 0 .38 Ac-ft TIME: 480 min I 11/21/03 3 :2 : 10 pm Marley Young Engineer page 2 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 BASIN SUMMARY BASIN ID: d NAME: 100 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 . 24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPE1A 0 . 69PERV IMP PRECIPITATION. . . . : 6 . 75 inches AREA. . : 0 . 69 Acres 8 . 00 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE : 1 .59 cfs VOL: 0 .58 Ac-ft TIME : 480 min BASIN ID: dbuild NAME: 100 year storm off of building SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 10 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPE1A PERV IMP PRECIPITATION. . . . : 6 . 75 inches AREA. . : 0 . 00 Acres . 0 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 0 . 00 98 . 00 TC. . . . : 0 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 0 . 14 cfs VOL: 0 . 05 Ac-ft TIME: 480 min I 11/21/03 3 :2 :11 pm Marley Young Engineer page 3 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 - STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. ST Description: SEDIMENT POND DURING CONSTRUCT Length: 50 .50 ft. Width: 20 . 00 ft. Side Slope 1: 3 Side Slope 3 : 3 Side Slope 2 : 3 Side Slope 4: 3 Infiltration Rate: 6 . 00 min/inch STAGS <----STORAGE----> STAGS <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --AC-Pt- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 100.00 cII0.0000s�0.0000- 100.55 621.48 0.0143 n 101.10 1383 0.0317 101.65 2296 0.0527 100.05 51.030 0.0012 100.60 684.73 0.0157 101.15 1459 0.0335 101.70 2387 0.0548 100.10 103.13 0.0024 100.65 749.15 0.0172 101.20 1537 0.0353 101.75 2480 0.0569 100.15 156.30 0.0036 100.70 814.75 0.0187 101.25 1616 0.0371 101.80 2573 0.0591 100.20 210.56 0.0048 100.75 881.53 0.0202 101.30 1697 0.0390 101.85 2668 0.0613 100.25 265.91 0.0061 100.80 949.50 0.0218 101.35 1778 0.0408 101.90 2765 0.0635 100.30 322.36 0.0074 100.85 1019 0.0234 101.40 1861 0.0427 101.95 2863 0.0657 100.35 379.92 0.0087 100.90 1089 0.0250 101.45 1946 0.0447 102.00 2962 0.0680 100.40 438.61 0.0101 100.95 1161 0.0266 101.50 2031 0.0466 100.45 490.42 0.0114 101.00 1234 0.0283 101.55 2118 0.0486 100.50 559.38 0.0128 101.05 1308 0.0300 101.60 2207 0.0507 7 11/21/03 3 :2 :11 pm Marley Young Engineer page 4 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 - STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct ST STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 100.00 a0 2338 a 100.55 0.2932 101.10 0.3580 101.65 0.4280 100.05 0.2390 100.60 0.2989 101.15 0.3641 101.70 0.4346 100.10 0.2442 100.65 0.3046 101.20 0.3703 101.75 0.4413 100.15 0.2495 100.70 0.3103 101.25 0.3765 101.80 0.4480 100.20 0.2548 100.75 0.3161 101.30 0.3828 101.85 0.4548 100.25 0.2601 100.80 0.3220 101.35 0.3891 101.90 0.4616 100.30 0.2656 100.85 0.3279 101.40 0.3955 101.95 0.4685 100.35 0.2710 100.90 0.3338 101.45 0.4019 102.00 0.4754 100.40 0.2765 100.95 0.3398 101.50 0.4084 100.45 0.2820 101.00 0.3450 101.55 0.4149 100.50 0.2876 101.05 0.3519 101.60 0.4214 11/21/03 3 :2 :11 pm Marley Young Engineer page 5 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. T Description: Length: 65 . 00 ft. Width: 20 .00 ft. Side Slope 1: 3 Side Slope 3 : 3 Side Slope 2 : 3 Side Slope 4 : 3 Infiltration Rate: 6 . 00 min/inch STAGS <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- 100 00 0.0000 0.0000 100.80 1209 0.0278 101.60 2782 0.0639 102.40 4755 0.1092 100.05 65.639 0.0015 100.85 1297 0.0298 101.65 2893 0.0664 102.45 4892 0.1123 100.10 132.56 0.0030 100.90 1385 0.0318 101.70 3006 0.0690 102.50 5031 0.1155 100.15 200.78 0.0046 100.95 1475 0.0339 101.75 3120 0.0716 102.55 5172 0.1187 100.20 270.30 0.0062 101.00 1567 0.0360 101.80 3236 0.0743 102.60 5315 0.1220 100.25 341.13 0.0078 101.05 1660 0.0381 101.85 3354 0.0770 102.65 5459 0.1253 100.30 413.27 0.0095 101.10 1755 0.0403 101.90 3473 0.0797 102.70 5605 0.1287 100.35 486.75 0.0112 101.15 1850 0.0425 101.95 3594 0.0825 102.75 5753 0.1321 100.40 561.57 0.0129 101.20 1948 0.0447 102.00 3716 0.0853 102.80 5903 0.1355 100.45 637.73 0.0146 101.25 2047 0.0470 102.05 3840 0.0882 102.85 6054 0.1390 100.50 715.25 0.0164 101.30 2147 0.0493 102.10 3966 0.0910 102.90 6207 0.1425 100.55 794.13 0.0182 101.35 2249 0.0516 102.15 4093 0.0940 102.95 6362 0.1461 100.60 874.39 0.0201 101.40 2353 0.0540 102.20 4222 0.0969 103.00 6519 0.1497 100.65 956.03 0.0219 101.45 2458 0.0564 102.25 4353 0.0999 100.70 1039 0.0239 101.50 2564 0.0589 102.30 4485 0.1030 100.75 1124 0.0258 101.55 2672 0.0613 102.35 4619 0.1060 I a 11/21/03 3 :2 :11 pm Marley Young Engineer page 6 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct T STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> (ft) ---cfs-- (ft) ---cfs-- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 100 00 0.3009 s a 100.80 3 0.4061 101.60 0.5225 102.40 0.6502 100.05 0.3072 100.85 0.4130 101.65 0.5302 102.45 0.6585 100.10 0.3135 100.90 0.4200 101.70 0.5379 102.50 0.6669 100.15 0.3198 100.95 0.4271 101.75 0.5456 102.55 0.6754 100.20 0.3262 101.00 0.4342 101.80 0.5534 102.60 0.6839 100.25 0.3326 101.05 0.4413 101.85 0.5612 102.65 0.6924 100.30 0.3390 101.10 0.4484 101.90 0.5691 102.70 0.7010 100.35 0.3456 101.15 0.4557 101.95 0.5770 102.75 0.7096 100.40 0.3521 101.20 0.4629 102.00 0.5849 102.80 0.7182 100.45 0.3587 101.25 0.4702 102.05 0.5929 102.85 0.7269 100.50 0.3653 101.30 0.4775 102.10 0.6010 102.90 0.7357 100.55 0.3720 101.35 0.4849 102.15 0.6091 102.95 0.7445 100.60 0.3788 101.40 0.4924 102.20 0.6172 103.00 0.7533 100.65 0.3855 101.45 0.4998 102.25 0.6254 100.70 0.3923 101.50 0.5074 102.30 0.6336 100.75 0.3992 101.55 0.5149 102.35 0.6419 11/21/03 3 :2 :11 pm Marley Young Engineer page 7 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 STAGE DISCHARGE TABLE====____________________ OVERFLOW WEIR ID No. W Description: Ratio (h:lv) : 3 .2100 Weir length: 4 .0000 ft. El : 103 . 00 ft. Weir Increm: 0 . 05 STAGS <--DISCHARGE---> STAGE -DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 103.00 0.0000 103.30 2.5267 103.60 8.2960 103.90 17.352 103.05 0.1489 103.35 3.2694 103.65 9.5703 103.95 19.200 103.10 0.4341 103.40 4.0987 103.70 10.937 104.00 21.147 103.15 0.8215 103.45 5.0151 103.75 12.397 103.20 1.3016 103.50 6.0195 103.80 13.952 103.25 1.8706 103.55 7.1128 103.85 15.603 I 11/21/03 3 :2 :11 pm Marley Young Engineer page 8 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 HISTORY OF HYDROGRAPH ACTIVITY Date of Session: 11/15/03 12:15:26 am CLEARHIS MOVE LA to 5 0.1746 cfs 0.0671 ac-£t 8.00 hrs MOVE LB to 6 0.3446 cfs 0.1269 ac-ft 8.00 hre MOVE LC to 7 0.5227 cfs 0.1900 ac-ft 8.00 hrs MOVE LD to 8 0.8128 cfe 0.2943 ac-ft 8.00 hrs MOVE a to 5 0.3900 cfs 0.1472 ac-ft 8.00 hrs MOVE b to 6 0.7133 cfe 0.2638 ac-ft 8.00 hrs MOVE c to 7 1.0463 cfs 0.3848 ac-ft 8.00 hrs MOVE d to 8 1.5857 cfs 0.5830 ac-ft 8.00 hre LPOOL 1 ^1/2" 5 5 T W 9 Description MatchQ PeakQ Sto Die PkStg OutQ hyd Volume 1/2 0.39 0.39 T W 100.11 0.31 9 145.15 of LPOOL 2 ^2^ 6 6 T W 10 Description MatchQ PeakQ Sto Die PkStg outQ hyd Volume 2 0.71 0.71 T W 100.52 0.37 10 752.80 of LPOOL 3 "10" 7 7 T W 11 Description MatchQ PeaW Sto Die PkStg OutQ hyd Volume 10 1.05 1.05 T W 101.04 0.44 11 1636.50 of LPOOL 4 ^100^ 8 8 T W 12 Description MatchQ PeakQ Sto Die PkStg OutQ hyd Volume 100 1.59 1.59 T W 101.93 0.57 12 3547.23 of SPLIT W 1 13 17 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.3146 cfe 0.1472 ac-ft 8.17 hrs SPLIT W 2 14 18 I 11/21/03 3 :2 :11 pm Marley Young Engineer page 9 CADY PROFESSIONAL MALL INVESTIGATION TOTAL INFILTRATION PROJ 2003-19 HISTORY OF HYDROGRAPH ACTIVITY 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.3685 cfs 0.2638 ac-ft 8.33 hrs SPLIT W 3 15 19 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.4395 cfs 0.3848 ac-ft 8.67 hrs SPLIT W 4 16 20 0.0000 cfs 0.0000 ac-ft 0.00 hrs 0.5739 cfs 0.5830 ac-ft 9.17 hrs REM EXISTING DEVELOPMENT 10 YEAR STORM EVENT DIRECTED TO SEDIMENT POND LSTEND MOVE LC to 17 0.5227 cfs 0.1900 ac-ft 8.00 hrs LPOOL 2 "2" 17 17 ST W 18 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 0.52 0.52 ST W 100.45 0.28 18 504.37 of REM FULLY DEVELOPED 10 YEAR STORM EVENT DIRECTED TO SEDIMENT POND LSTEND LPOOL 2 "2" 7 7 ST W 18 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2 1.05 1.05 ST W 101.45 0.40 18 1946.67 of End program file E:\BGENIOUS\2003-19X.pgm Date of Sessicn: 11/16/03 4:44:45 pm BASIN dbuild "100 year storm off of building" 0.099 6.75 5.00 0.00 TYPEIA 5.00 0.20 0.000 0.000 0.00 0.099 98.00 SBUH 24.00 484.00 SHALLOW 110.00 0.0400 27.0000 LSTEND Date of Session: 11/21/03 3:0:37 pm I BIO SWALE CALCULATIONS 6 MONTH STORM EVENT BIO SWALE CALCULATIONS 100 YEAR STORM EVENT Page 1 of 2 Page 2 of 2 Owner Cady et al. Belfair Owner Cady et al. Belfair Project# 2003-19 Project# 2003-19 Remarks Bio Swale 6 month,24 hour storm events Remarks Bio Swale 100 year,24 hour storm events Design for Swale Capacity Design for Swale Capacity Date 11/15/03 Date 11/15/03 Q for the max.year storm event to use the Swale 6 Month Q for the max.year storm event to use the Swale 6 Mon. 2.973305 Q= 0.39 cfs cubic feet per second Q= 1.59 cfs cubic feet per second y= 0.19 Max. Bio Swale water depth in feet 2.973305 y= 0.37 Max. Bio Swale water depth in feet 100 Yr 2.9914 s= 0.02 Slope of Bio Swale in feet per foot s= 0.02 Slope of Bio Swale in feet per foot Z= 3 Swale side slope 3:1 Z= 3 Swale side slope 3:1 Note: The free board above the storm event is double the 100-year event depth Note: The free board above the storm event is double the 100-year event depth (See Manual-III-6-19:SC-14.) (See Manual-III-6-19:SC-14.) Use DOE Manual,page III-6-13 Formula(6-9) Use DOE Manual,page III-6-13 Formula(6-9) b=[Qn/(1.486)'(y^1.667)'(s^0.5)j-Zy b=[Qn/(1.486)'(y^1.667)'(s^0.5)]-Zy Note-Assume Q is directed to both ends and CD is in middle. Note-Assume Q is directed to both ends and CD is in middle. Q = 0.39 Q = 1.59 n = 0.06 n = 0.06 (See Manning's Roughness Coefficients(n)IV Highway Channel and (See Manning's Roughness Coefficients(n)IV Highway Channel and Swales with Maintained Vegetation) Swales with Maintained Vegetation) A. Depth of flow up to 0.7 feet: A. Depth of flow up to 0.7 feet: 1.Bermuda grass--Length 4 to 6 inches=n=.09 to.05;Use=0.06 1. Bermuda grass--Length 4to 6 inches=n=.09 to.05; Use=0.06 Q n = 0.0234 Q n = 0.0954 (y^1.667) = 0.06276 (y^1.667) = 0.19063 (s^0.5) = 0.141421 (s^0.5) = 0.141421 (-Zy) _ -0.57 (-Zy) _ -1.11 b = 1.204189 b = 1,271345 Swale has a maximum lenth of 85 ft. Swale must be widened to Swale has a maximum lenth of 85 ft. Swale must be widened to compensate for shorter length than 200'. -- See Page III-6-20,paragraph CO-1 compensate for shorter length than 200'. -- See Page III-6-20,paragraph CO-1 200/ 81 x 1.204189 = 2.973305 feet design width 200/ 85 x 1.271345 = 2.9914 feet design width 3 ft.use 3 ft.use Flow Velocity Check Flow Velocity Check v=Q/A v=Q/A A=Cross Sectional Area= by+Z'(y^2) A=Cross Sectional Area= by+Z'(y^2) A= 0,337096 A= 0.881098 Therefore Therefore v= 1,156941 fps < 1.50 fls =O.K. v= 1.804567 fps < 5.00 fps =O.K. REVIEW OF PIPE SIZE, PIPE SLOPE AND MAXIMUM VERSUS ACTUAL CFS A A B C D E F G H 1 J 1 PIPES RUNNING 80%FULL I USING PVC PIPE 2 Pipes that run at 80%full run at full ca ilty Revised 8/15/01 3 4 Q= 1.486/n "Rh^2/3 " S^1/2'Area = area of water in pipe 5 S^1/2 = slope of pipe ft/ft to the 1/2 ower 6 Rh^2/3 = h dralic radius to the 2/3 er 7 1.48&n if n-1 0.013 then 1.486/n 1114.30771 8 As a reference 9 TABLE 3, AREA WETTED PERIMETER AND HYDRAULIC RADIUS 10 1 OF PARTIALLY FILLED CIRCULAR PIPE 11 Section 7.3; Page 138; Book-Hydraulics of Culverts by Hendrickson Jr 12 Published by the American Concrete Pipe Association 1957 13 14 d/D = 0.8 60% of the diameter filled with water 15 area/D^2 = 0.6736 factor when d/D= 0.8 16 Wet. er./D = 22143 factor when d/D= 0.8 17 h d.rad./D = 0.3042 factor when d/D= 0.8 18 then 19 Pipe Slope= Q= V= Pipe Slope Q = V = 20 Diam. ft/ft cfs velocity Diam ft/ft cfs vellocIty 21 3 OA065 0.070 1.6528 4 0.0065 0.150 2.0024 22 3 0.01 0.086 2.0501 4 0.0072 0.158 2.1075 23 3 0.015 0.106 2.5108 4 0.008 0.166 2.2215 24 3 0.02 0.122 2.8992 4 0.0092 0.178 2.3823 25 3 0.03 0.149 3.5508 4 0.0186 0.254 3.3873 26 3 0.04 0.173 4.1001 4 0.0211 0.270 3.6078 27 3 0.05 0.193 4.5841 4 0.03 0.322 4.3019 28 3 0.06 0.211 5.0216 4 0.05 0.416 5.5538 29 3 0.07 0.2281 5.4240 4 0.07 0.492 6.5713 30 31 6 0.004 0.347 2.0587 8 0.0031 0.647 2.1600 32 6 0.006 0.425 2.5213 8 0.0041 0.747 2.4941 33 6 0.0075 0.475 2.8189 8 0.0061 0.915 3.0547 34 6 0.01 0.548 32550 8 0.007 0.988 32994 35 6 0.012 0.600 3.5657 8 0.01 1.181 3.9436 36 6 0.015 0.671 3.9866 8 0.015 1.446 4.8299 37 6 0.02 0.775 4.6033 8 0.02 1.670 5.5771 38 6 0.03 0.949 5.6379 8 0.03 2.045 6.8305 39 6 0.04 1.096 6.5101 8 0.181 5.009 16.7312 40 41 10 0.004 1.354 2.8944 12 0.006 2.697 4.0033 42 10 0.007 1.791 3.8289 12 0.01 3.481 5.1682 43 10 0.008 1.915 4.0933 12 0.02 4.923 7.3090 44 10 0.01 2.141 4.5765 12 0.03 6.030 8.9517 45 10 0.017 2.791 5.9670 12 0.041 6.963 10.3365 46 47 18 0.0028 5.432 3.5841 24 0.00584 16.897 6.2710 48 18 0.01 10.266 6.7732 24 0.00608 17.240 6.3985 49 181 0.02 14.518 9.5788 24 0.00956 21.618 8.0234 50 STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for January 13, 2004 REVISION TO THE SITE REDEVELOPMENT for Reid Realty Site Location: 23861 NE State Route 3, Belfair, WA 98528 Section 29, T23 N, R1W, W.M., Belfair, Mason County, WA Prepared for: Alan Cady, et al Contact Person: Alan Cady 9939 Mickelberry Road NW Silverdale, WA 98383 (360) 692-6102 Prepared by: MARLEY L. YOUNG, CONSULTING ENGINEER P.O. Box 1343 Shelton,WA 98584 (360)426-7475 Project No. 2003-19 (2003-19b, pgm) RECEIVED Revised January 13,2004 JAN 12 2004 FOSARCHITECTS MS MARLEY L. YOUNG, CONSULTING ENGINEER Engineering P.O. BOX 1343, SHELTON, WA 98584-0959 storm eter site Plans (360)426-7475 FAX (360) 426-5789 Sewer Bdeeslcns Marley L. Young, P.E., P.L.S. a J Civil Engineer& Land Surveyor PROJECT ENGINEER'S CERTIFICATION I hereby certify that this Stormwater and Erosion/Sediment Control Site Plan prepared for Alan Cady,et al,has been prepared by me or under my supervision and meets minimum standards of Mason County and normal standards of engineering practice. I understand that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me. Marley L. Young, P.E.,P.L.S. j 1414 �� Co ISTE �s�4NAL DCPiRES 3151e, Marley L.Young,Consulting Engineer Project No.2003-18 DESIGN CRITERIA SUPPORT 2003-19b Cady The Reid Realty, Inc.,building is located on property owned by the Cady family. The property has been business-oriented for at least twenty-five years. In listening to the owners of the property,they have told me that there is no stormwater sewer system,ditch system that would carry the surface water away from the property. This fact eliminated any design that included detention and surface discharge. They have also indicated that all rainwater infiltrates onsite and this onsite infiltration has been the method of natural stormwater disposal for the past twenty-five plus years,and the owners wish to continue with this preferred method of stormwater disposal. The way the total property is contoured,they do not receive stormwater from offsite sources. Two holes were drilled in the area of the proposed infiltration pond. The purpose of the holes was to determine the infiltration rate and the elevation of the ground water. The soils were identified as silty sand with a perc rate of 1.2 minutes per inch. The ground water elevation was found at 62.00+/-feet. Soils investigations determined that the ground water was within between five and six feet of the ground surface. This condition reduces the options available for onsite storage via large tanks or vaults because of the buoyancy factor. The inability to"empty"a large tank or vault reduced their desirability and efficiency. The available perc rate of 1.2 minutes per inch has been deemed by the county reviewers as too fast. The County is concerned that the stormwater would perc too quickly into the ground and surcharge the ground water and cause water problems `down stream' of the site. To reduce this concern we are proposing a retention pond for total onsite disposal by infiltration. We are also including as part of the retention pond design that the pond include an imported sand floor that will slow the infiltration from 1.2 minutes per inch to 7.5 minutes per inch. This would effectively retain the stormwater onsite and the discharge off site through infiltration would satisfy the streambank erosion control requirements of the D.O.E. Manual. The discharge offsite through infiltration would be less than the 50 percent of the calculated existing 2-year storm event discharge, and much less than the existing 10— 100 year storm event discharge. Alan Cady,et al—Belfair Site Redevelopment-Revised TABLE OF CONTENTS Page Engineer's Certification Design Criteria Support Table of Contents Best Management Practices(BMPs) .............................................................. 1 Large Parcel Stormwater Site Plan I. Project Overview .............................................................. 2 Minimum Requirements#1411 .............................................................. 3 II. Plot Plan .............................................................. 5 II1. Preliminary Conditions Summary .............................................................. 5 W. Off-site Analysis .............................................................. 5 V. Permanent Stormwater Quality Control Plan ....................................................... 5 Storm Event Design Assumptions .............................................................. 6 VI. Special Reports and Studies(Not Applicable to this Plan) ...................................... 7 VII. Basin and Community Planning(NA) .............................................................. 7 VIII. Permits ............. 7 IX. Erosion and Sediment Control Plan .............................................................. 8 Minimum Requirements#1415 .............................................................. 9 X. Bond Quantity Worksheets(NA),Detention Facility Summary Sheet and Sketch (NA), Declaration of Covenant .............................................................. 11 XI. Operation and Maintenance Manual .............................................................. 11 Changed Conditions .............................................................. 12 ************************************************************************************* ATTACHMENTS SUPPORTING CALCULATIONS CIVIL DRAWINGS Marley L.Young,Consulting Engineer Project No.2003-19 REVISED January 13,2004 STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for Alan Cady,et al—Reid Realty Site Redevelopment,Belfair,Washington The Puget Sound Water Quality Management Plan(PSWQMP), which is administered by the State of Washington Department of Ecology,mandates that all counties and cities within the Puget Sound drainage basin adopt ordinances to control runoff from new development and redevelopments. The PSWQMP also directs local governments to adopt stormwater programs that must include minimum requirements that are consistent with the PSWQMP, and which are substantially equivalent t the DOE's Stormwater Management Manual for the Puget Sound Basin, (DOE's Technical Manual). The goal of the Puget Sound Water Quality Management Plan is to: ■ Protect and restore beneficial uses of aquatic resources, including shellfish beds,fish habitat,and other resources; ■ Prevent contamination of sediments from urban runoff; ■ Meet standards for water and sediment quality by reducing pollutant discharges from stormwater throughout Puget Sound. BEST MANAGEMENT PRACTICES(BMPs) Best management practices(BMPs)are defined as physical, structural, or management practices that, when used singly or in combination, prevent or reduce pollution of water. Specific BMPs have been developed by Ecology to control stormwater runoff(quality and quantity)for protection of receiving waters. There are three main reasons for applying BMPs before considering advanced treatment. First, it has been shown through research and experience that BMPs can significantly reduce pollutants in stormwater. Using BMPs to control localized discharges is cost effective in comparison to treating large volumes of water. Second,our lakes and streams depend on stormwater to provide adequate flow for fish habitat and water quality. Our groundwater resources also depend on stormwater for recharge. BMP implementation offers a way to discharge water back into the natural system. Third,and perhaps most important, stormwater management programs demand the conscientious use of best management practices to protect water quality. Specific BMPs that cover stormwater runoff quality and quantity have been included in Ecology's Technical Manual. Those BMPs can be divided into three basic categories, including Source Control BMPs,Runoff Treatment BMPs and Streambank Erosion Control BMPs. Source Control BMPs are designed to prevent pollutants from entering stormwater by eliminating the source of pollution or by preventing contact of pollutants with rainfall and runoff. Source controls are usually the most cost-effective because they reduce or eliminate the need for treatment BMPs. Implementing source control BMPs generally involves relatively simple and straightforward actions. Examples of source control BMPs include erosion control(e.g.,covering disturbed soil),covering material storage areas, and eliminating illicit discharges. Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised Runoff Treatment BMPs are designed to remove pollutants contained in stormwater runoff. These types of BMPs are the second line of defense in protecting stormwater quality. Examples of runoff treatment BMPs include infiltrated basins,bioswales and sediment ponds. Streambank Erosion Control BMPs are designed to protect stream ecosystems from erosion and sedimentation. Types of streambank erosion control BMPs include flow attenuation BMPs for reducing peak flows from a development(e.g., detention ponds, infiltration trenches),and streamside stabilization BMPs used to stabilize eroding streambanks. I. PROJECT OVERVIEW PROPOSED PROJECT DESCRIPTION: The proposal is a redevelopment of an existing commercial building site. The existing building will eventually be razed. There will be an increase in asphalt parking. Stormwater will be disposed of by onsite infiltration. LEGAL DESCRIPTION The site is within the NE '/4 ofthe SE '/4 of Section 29,Township 23 North,Range 1 West, W.M., Belfair, Mason County, Washington. EXISTING CONDITIONS: The Reid Realty, Inc., building is located on property owned by the Cady family. The property has been business-oriented for at least twenty-five years. In listening to the owners of the property,they have told me that there is no stormwater sewer system/ditch system that would carry the surface water away from the property. They have also indicated all rainwater infiltrates on site and this onsite infiltration has been the method of natural stormwater disposal for the past twenty-five years,and the owners wish to continue with this preferred method of stormwater disposal. The way the total property is contoured,they do not receive stormwater from offsite sources. There are no trees on the property. A good percentage of the lot consists of existing asphalt parking and gravel parking. GENERAL LOCATION: Reid Realty, Inc., site address is 23832 State Highway 3, Belfair, WA 98528. The site is on State Highway 3,north of the Old Belfair Highway. STORMWATER AND EROSION/SEDIMENT CONTROL PLAN REQUIREMENT DETERMINATION: Projects that add 5,000 square feet or more of new impervious surface must comply with all the large Parcel minimum Requirements. A Large Parcel Erosion and Sediment Control Plan is discussed,and the necessary BMPs are included in this report. The report will review the components of the Large Parcel Stormwater Site Plan, which include the temporary erosion and sediment control necessary during construction,permanent stormwater quantity control,civil drawings and specifications, and operation and maintenance recommendations for the needed stormwater facilities. This project will comply with the following Large Parcel minimum Requirements#1 through#I I found in Section I-2.5 of the Department of Ecology' Stormwater Management Manual for the Puget Sound Basin(the Technical manual). Minimum Requirement#1: EROSION AND SEDIMENT CONTROL See Section IX, Erosion and Sediment Control Plan (Requirements #1415). 2 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised Minimum Requirement#2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS Natural drainage patterns shall be maintained,and discharges from the site shall occur at the natural location,to the maximum extent practicable. No surface water drainage flows through this project. Minimum Requirement#3: SOURCE CONTROL OF POLLUTION Where necessary to prevent the migration of silt during construction, the owner/contractor shall construct channels to keep overland flows away from the area under construction. If dust becomes a problem, dust control methods using water shall be employed.. If necessary to reduce tracking of mud and debris onto paved roads, the owner/contractor shall utilize a construction entrance rock pad. If required, migration-sensitive soils shall be covered with straw mulch or black plastic to prevent off-site migration of soil. The erosion control plan consists of installing a construction entrance, a sediment trap and filter fabric fence. Minimum Requirement#4: RUNOFF TREATMENT BMPS Grass swale will be used as the method of treatment. Minimum Requirement#5: STREAMBANK EROSION CONTROL Total infiltration is on site, and infiltration rates will meet or exceed STREAMBANK EROSION CONTROL requirements. Minimum Requirement#6: WETLANDS NA— The site does not include wetlands. Minimum Requirement#7: WATER QUALITY SENSITIVE AREAS NA Minimum Requirement#8: OFF-SITE ANALYSIS AND MITIGATION NA — Total infiltration onsite; therefore, offsite analysis is not required. Minimum Requirement#9: BASIN PLANNING An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. NA—No basin plan has been established at this location. Minimum Requirement#10: OPERATION AND MAINTENANCE An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs, and the party(or parties)responsible for maintenance shall be identified. The owner is responsible for operation and maintenance of the stormwater facilities. A "Declaration of Covenants Associated With Privately Maintained Storm Drainage Facilities", which must be recorded and submitted to Mason County as part of the approval process, has been prepared for the project. A copy of the unsigned document is included in the Attachments. Minimum Requirement#11: FINANCIAL LIABILITY Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. NA—Mason County has not indicated that a financial instrument will be required. 3 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised II. PLOT PLAN Engineer's Civil Drawings have been developed for the project showing the location of the improvements and the layout of the proposed Permanent Stormwater Control BMPs, and an Erosion/Sediment Control Plan to be used during construction. By reference these drawings are made a part of this report. III. PRELIMINARY CONDITIONS SUMMARY See Section I, Project Overview. IV. OFF-SITE ANALYSIS (No off-site analysis is required. See Min. Req. #8 above.) Wetlands or Water of the State This site does not contain wetlands and is not within 200 feet of any waters of the State. Analysis of the 100-year Flood This site does not contain or abut a Federal Emergency Management Administration(FEMA)identified stream and is,therefore,outside any 100-year flood plain. V. PERMANENT STORMWATER QUALITY CONTROL PLAN All storm events are collected and directed to the retention pond through a grass swale. Emergency spill containment and control has been explained above. STORM EVENT DESIGN ASSUMPTIONS Based on DOE's Stormwater Management Manual: STORM EVENT The stormwater program Water Works(software for hydrology by Engenious Systems,Inc.)was used to model the storm flows,retention, infiltration and releases. Rain Precipitation(in.) Six-month,24-hour Storm Event 2.24 (6-mo. @ 64%of 2-yr.) Two-year,24-hour Storm Event 3.50 Ten-year,24-hours Storm Event 4.75 Hundred-year, 24-hour Storm Event 6.75 Rainfall choice IA Hydrograph SBUH** ** Santa Barbara Urban Hydrograph method DRAINAGE BASIN Indianola sandy loam(Id), 0-5 percent slopes Hydrologic Soil Group A Infiltration Rate for Pond 7.5 min./inch CN#for Impervious 98 CN# for Pervious—Landscaping/Undeveloped 85 NOTE: Given the Storm Event, Soil Type and Land Use,the Runoff Curve Number(CN#) is an indicator of the total surface and subsurface runoff. 4 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised POST DEVELOPMENT STORMWATER RUNOFF for 1.24 ACRES Storm Event 6-month Two-year Ten-year 100-year Pre Flow cfs 0.313 0.633 0.969 1.519 Pre Volume ac ft 0.121 0.233 0.351 0.547 Post Flow cfS 0.394 0.719 1.054 1.597 Post volume ac ft 0.148 0.266 0.388 0.587 INFILTRATION-RETENTION POND—CRESCENT SHAPE Floor Length ft 72.50 WaterWorks Floor Width ft 15.37 WaterWorks Side Slopes: 3H to IV Infiltration Rate min./inch 7.5 TOTAL SURFACE DISCHARGE Storm Event Two-year Ten-year 100-year Post Flow cfs 0.00 0.00 000 Pond Depth ft 0.80 1.40 2.32 TOTAL INFILTRATION Storm Event Two-year Ten-year 100-year Post Infil cfs 0.307 0.390 0.532 CHECKING FOR COMPLIANCE TO STREAMBANK EROSION CONTROL Post Infil cfs 0.307 0.390 0.532 Pre Flow cfs 0.633 0.969 1.519 PERCENTAGE 2-year is less than 50% OK 10-100 years are far less than 100% OK SEDIMENT TRAP Using proposed completed conditions to calculate runoff capacity requirements. Volume capacity 1,947 cf with a depth of 1.45 feet. BIOSWALE Floor length: ft 85 Floor width: ft 3 Maximum Bioswale Slope: 2% Side Slopes: 3H to 1V Cubic Feet Per Second: 6 mo. =0.39 cfs; 100-yr. = 1.59 cfs Manning's Roughness Coefficient(n)6-mo. (n)=0.06; 100-yr. (n)=0.06 Velocity in Bioswale: 6-mo. = 1.16 fps; 100-yr. = 1.80 fps Min. Water Depth: 6-mo.=0.19 ft; 100-yr.=0.37 ft. Min. Bioswale Depth: 0.74 ft.(double the 100-yr.water depth) Refer to Supporting Calculations for further details. VI. SPECIAL REPORTS AND STUDIES Geotechnical analysis of infiltration 5 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised VII. BASIN AND COMMUNITY PLANNING NA VII. PERMITS Agency Permit/Approval Mason County Grading Permit IX. EROSION and SEDIMENT CONTROL PLAN Temporary Erosion Control This project includes temporary erosion control. See Civil Drawings. The disturbance to the property is minimal. The types of soils are sandy, gravelly, and do not lend themselves to migration. Erosion control will use silt fences, temporary sediment pond, and the stabilization of the construction entrance. Project Description/Existing Site Conditions Refer to Section I, Project Overview. Adjacent Areas Impacts NA —No impact anticipated because of the reduced infiltration rates. SCS Soils Description The Soil conservation Service—Soil Survey of Mason County Series 1951,No.9, Issued September 1069, shows this property having soils type Indianola sandy loam(Id), 0-5 percent slopes. Soils conditions found on the property may not match exactly the soils described by SCS. Critical Areas No critical areas have been identified on this site. Erosion and Sediment Control Measures Minimum Requirements Mason County has adopted the Department of Ecology"Stormwater Management Manual for the Puget Sound Basin. All projects that disturb more than one acre must develop a Permanent Stormwater Quality Control Plan. (Mason County Ordinance 141-97) EROSION AND SEDIMENT CONTROL REQUIREMENTS The existing soils on the site have been classified by the SCS as Indianola sandy loam(Id), 0-5 percent slopes. I feel that the erosion and sediment control system hereinafter proposed will adequately provide the necessary erosion and sediment protection. The fifteen large parcel minimum requirements specified by DOE are: #1: Stabilization and Sediment Trapping All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30, no exposed and unworked soils shall remain unstabilized for more than 2 days. From May 1 to September 30,no exposed and unworked soils shall remain unstabilized for more than 7 days. Prior to leaving the site,stormwater runoff shall pass through a sediment pond or sediment trap, or other appropriate BMPs. 6 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised #2: Delineate Clearing and Easement Limits The clearing limits shall be defined by the owner. #3: Protection of Adjacent Properties The underlying soils have very little potential for migration. Protecting adjacent property from damage from sediment deposition does not appear to be a problem. #4: Timing and Stabilization of Sediment Trapping Measures Sediment trap and filter fabric will be placed as shown on the Civil Drawings. #5: Cut and Fill Slopes The infiltration pond shall have side slopes no steeper than 3 feet horizontal to 1 foot vertical(3:1). Other minor side slopes will be 2 or 3:1. #6: Controlling Off-site Erosion Off-site erosion is not anticipated to become an issue. #7: Stabilization of Temporary Conveyance Channels and Outlets It is anticipated that the water velocity for ground surface flows will not reach erosion velocity. All stormwater will be infiltrated on site. #8: Storm Drain Inlet Protection See Civil Drawings for storm drain inlet protection. #9: Underground Utility Construction Architectural and Civil drawings put contractor on notice as to the installation requirements of underground utilities. #10: Construction Access Routes Construction vehicles access shall be,whenever possible, limited to one route. Access points shall be stabilized to minimize the tracking of sediment onto public roads. There shall be only one access to the site for construction purposes. See Civil Drawings for location and detail. #11: Removal of Temporary BMPs All temporary erosion and sediment control BMPs will be removed when final site stabilization is achieved. #12: Dewatering Construction Sites Dewatering is not necessary. The soil characteristic is highly porous. #13: Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediments that occur onsite during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14: Maintenance All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. #15: Financial Liability Not Applicable to this project. 7 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al-Belfair Site Redevelopment-Revised Permanent Stabilization At the conclusion of site construction improvements,within seven days permanent site stabilization shall be completed by spreading seed and mulch on all exposed soils to establish a ground cover. Use the following recommended seed mixture for erosion control, or a Count-approved alternate seed mixture. Proportions Percent Percent Name by Weight Purity Germination Redtop(Agrostis alb a) 10 percent 92 90 Annual rye(Lolium multiflorum) 40 percent 98 90 Chewing fescue 40 percent 97 80 (Festuca rubra commutata) (Jamestown,Banner,Shodow,or Koket) White dutch clover(Trifolium repens) 10 percent 96 90 The following is a guide for use of recommended mulch material: Application Rates Depth Mulch Quality Per 1000 Per of Material Standards Sq. Feet Acre Application Remarks Gravel,Crushed Washed'/,to 9 CY 3 inches Good for short slope and Stone 1'/z-inch around woody plants and ornaments. Use where Subject to foot traffic. Hay or straw Air dry.Free from 75-100 lbs 1.5 to Min.2 inches Use where needed for more weed seed and pounds 2.5 tons than 3 mos. Subject to coarse material. (Approx. blowing—keep moist or 2 in.thick) 90-120 Bales When used on critical areas, Wood Fiber No growth organism 25 to 30 1000 to 1500 double application rate. Cellulose(Partly inhibiting factors pounds pounds Apply with hydromulcher. Digested wood factors. No tie-down required. fibers) Stormwater Management Considerations Please see Section V, "Permanent Stormwater Quality Control Plan"for a complete description of the stormwater management plan. Maintenance The responsibility for maintaining the facilities will lie with the owners of the property or their assigns. For maintenance recommendations please see Section XI, "Operation and Maintenance Manual"below. Calculations Calculations are briefly described in Section V, "Permanent Stormwater Quality Control Plan"above, and included in the attached Supporting Calculations. X. BOND QUANTITIES WORKSHEET,RETENTION/DETENTION FACILITY SUMMARY SHEET AND SKETCH,AND DECLARATION OF COVENANT Bond Quantities Worksheet—NA Retention/Detention Facility Summary sheet—NA Declaration of Covenant—Mason County requires that a "Declaration of Covenants Associated with Privately Maintained Storm Drainage Facilities"be executed and filed with Mason County as part of the approval process. A copy of the unsigned document is included in the Attachments. 8 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised XI. OPERATION&MAINTENANCE MANUAL MAINTENANCE PLAN of the The responsibility for maintaining the facilities mi lie mlze the need fothe r extensivemaintenances assigns (e.g.,Contractor). The facilities are designed MAINTENANCE OF TEMPORAR RS�IIONtB iMPos DURINGs CONSTRUCTION sift sediment pond. If the During construction the mayor maintenance drainage carries mud or debris,additional silt fences should be placed in the path of the drainage to eliminate any siltation from exiting the project site. regularly especially after any All erosion and sediment control BMPs installed shall be inspected Y� Y large storm. Maintenance, including�tr otslthes beet flowproper oinfiltration sediment must be removed.) done � necessary. (Generally sediment that MAINTENANCE OF PERMANENT STORMWA R C thTROL FACcumulatio Iof o 1 and sediment. The The Type 30 catch basin shall be inspectedsemi-yearly catch basin should be cleaned with oil-absorbing materials every six months,spring and fall, if wan-an In the fall inspect the grass Swale to assure that the grass will stand 4-5 inches through winter. Inspect the swale to assure that it is clear of debris that hall�inspected flow and ford that the flow is black or brown discoloration orout the staining width of the Swale. In the spring the swale s P� caused by fluids. The stained soil and sod should be replaced and the old material disposed of in the appropriate manner. the silt If the infiltration retention pond has o d shall also on of bekeptlt that cleart of all settleab restrict le infiltration rate, floating debris. must be removed. The infiltration p within 24 hours of a 2 year Ideal condition is that stormwater in the pond would disappear(infiltrate) storm event. CHANGED CONDITIONS: The conclusions and recommendations in this report are based on my interpretation of site conditions,and the expectation ls te. In the event that the scope of the project at my onsite exploratory efforts adequately ef or e fll the surface and sub-surface conditions throughout the location of the improvements or surface/subtions diff from those I surface will be made relied on in this alternative or report,I o the changed condition should be advised. At that time,a review g remedial recommendations given as requested. db This Stormwater Site Plan has been prepare y• Marley L.Yo g, E., . .S. Marley L.Young,Consulting Engineer 9 project No.2003-19 • Alan Cady,et al—Belfair Site Redevelopment-Revised ATTACHMENTS Marley L.Young,Consulting Engineer Project No.2003-19 r Alan Cady,et al—Belfair Site Redevelopment-Revised I DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES (Copy of unsigned document) Marley L.Young,Consulting Engineer Project No.2003-19 RETURN ADDRESS GRANTOR(S)(Last,First and Middle Initial) GRANTEE: MASON COUNTY DEPARTMENT OF PUBLIC WORKS DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES Declaration of Covenant In consideration of approval of the development known as ,relating to real property legally described as follows: County Assessor's Property Tax Parcel Number The undersigned,as owner(s),covenant and agree that: 1. If at any time Mason County reasonably determines that maintenance or repair work is required to be done to the existing,approved storm drainage facilities installed on the property described above and located outside of any public right of way(which will mean repair and/or clean out of the existing system only to the same standards as originally installed and approved),the Director of the Department of Public Works shall give the current owners seven days notice that the County intends to perform such maintenance or repairs,or to have them performed by others. If the current owners have not completed or are not diligently pursuing the repair or maintenance of the system and it becomes necessary for Mason County to perform the work,the current owners will assume responsibility for the cost of such maintenance or repair and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments,and any costs or fees incurred by the County,should any legal action be required to collect such payments,will be borne by the parties responsible for said reimbursements. 2. If at any time Mason County reasonably determines that the existing and approved storm drainage system on the property poses a hazard to life and limb,or endangers property,or adversely affects the safety and operations of a public way,due to failure,damage or non-maintenance of the existing on-site storm system,and that the situation is so adverse as to preclude written notice to said owners,the Director of the Department of Public Works may take the measures necessary to eliminate the hazardous situation (which will mean repair or clean out of the existing system only to the same standards as originally installed and approved)provided the Director has first made a reasonable effort to locate said owner before These covenants are intended to protect the value and desirability of the real property described above,and to benefit all the citizens of Mason County.They shall run with the land and be binding on all parties having or acquiring from the current owners or their successors,any right,title or interest therein, and to the benefit of all the citizens of Mason County. Signature Signature Owner Owner Address Address City,State,Zip City,State,Zip Phone: Phone: STATE OF WASHINGTON, . (INDIVIDUAL ACKNOWLEDGMENT) County of MASON Notary Public in and for the State of Washington,residing at do hereby certify that on this day of ,200_,personally appeared before me to me known to be the individual described in and who executed the within instrument and acknowledged that signed and sealed the same as free and voluntary act and deed for the uses and purposes herein mentioned. GIVEN UNDER MY HAND AND OFFICIAL SEAL this day of ,200_. Notary Public in and for the State of Washington,residing at in said County. My Commission expires l I 12/29/03 ICON 11:46 FAX 3604278425 MASON COUNTY E C V E ��`T DEC 9 20fz MASON COUNTY 1 i =0S TER&WILLIAMS PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER ARCHITECTS SheboTM WJfhYgWD 99534 DATE: December 26'h, 2003 INTER-DEPARTMENTAL COMMUNICATIONS TO: Rick Mraz,DCD-Planner FROM: Alan A. Tahja,P/W-Co.Hydr.Engr. WO#PLG-03 SUBJ: Stormwater Site Plan (SSPL NAME: Cady Office Bldg- Belfair COM2003-00197 Rick, The Stormwater Site Plan(SSP)prepared for the proposed commercial development/redevelopment of the Cady Family/Reid Realty property in Belfair,has been received and reviewed by Public Works. Total infiltration of storm events through a 100 year 24 hour event is promoted as the main destination for collected stormwater runoff. The proposed infiltration gallery is proposed to be preceded by a water quality treatment Swale sized to provide treatment for Ecology's Water Quality Design Storm event. The engineer who developed the stormwater site plan has indicated that offsite analysis and mitigation is not necessary due to the intended infiltration of collected stormwater runoff. Normally offsite impacts are not anticipated from sites which are able to infiltrate their stormwater runoff,but the urbanized area of Belfair in which the subject property is located in, has existing problems with a high groundwater table,and wet surface conditions in the down- gradient properties from the Cady property.These existing problems raise the need to ascertain potential surface and sub-surface flows and impacts. Since the high groundwater table problems have been brought to the County Engineer's attention, stormwater features in the general urban Belfair area have been required to employ detention facilities instead of or in concert with retention facilities. Since the Cady property has no apparent surface discharge location,other than sheet flow to neighboring properties or infiltration,it seems apparent that infiltration is almost the only method available short of developing a storm sewer route to an acceptable disposal location. Since infiltration appears to be the most practical and financially appealing stormwater disposal practice,limiting the infiltration rate seems a logical solution to diminishing down-gradient property groundwater problems. If an infiltration facility is pursued as part of the final design, soil exploration information File: H:%wPXSttmwt=1ReviewalCady-Re1d Realty.doc JASur 4,uu11�- y gprl 11:47 FAX 3604278425 d in accordance withwithEcol°gy's tration rates will need to be determine Authority,s Stormwater reporting,and inf'l cedures{See the Puget Sound Water Q lin' Technical Manual PrO et Sound Basin version 1992, ChapW Mattagement Manual for the Pug engineer (Marley Young,P•E•},and with Jerry Hauth, Project engin recommend live discussed these issues witl'the��this time that Public Worcannot om the developed the County Engineer, and can only p° site plan.Detaining ti proposed stormw�r to be a likely approach to acceptance of the currently P Y'O prescribed rate currently aPP� earn erosion control tra it onsite at a P Infiltrating stormwar runoff at a downstr potential site and infil rMo ff but determining disposing of site developed potential infiltration rate, discharge rate has been discussed a P cted to be addressed in the Stormwater Site unpacts from a detention-infiltration facility is expo plan as a potenti offsite impact al os moons regarding these please feel free to contact me at County extensi°n 461 if you have any questions mments,or if you feel any features need further discussion or attention. co :A;a ' ely, A. Tahya L8 - o°lam 2 LC- ` LD 'ews\CadY-Reid RealtY.doc 'F ile: S:\wP\atrmwtr\Revs J FROM GEOTESTLRH HHUNt NU. -. JbU(Z)44t34tl GEOTECHNICAL TESTING-LABORATORY MARLEY YOUNG CONSMTING L+NGINEER p. O.Box 1343 SHELToN,WA 98584 Re: Pert.testing fos infiltration pond Reid Realty,Belfair,WA Gentlemen: on Nov. 7,2003 for the above referenced Project' The soil �bIW perc holes were dug for inhhration testing Hole#2,in the area where the Proposed Swale is to be infiltration classification was Type A- The pert rate for located was 1.2 minutes per inch. 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Par 3 1 Alan Cady,et al—Belfair Site Redevelopment-Revised SUPPORTING CALCULATIONS Marley L.Young,Consulting Engineer Project No.2003-19 POND DESIGN The computer program, WaterWorks, uses rectangular trapezoidal basins for the retention/detention facilities analysis. When designing a basin,other than rectangular,the WaterWorks trapezoidal basin must be modified by length,width, and side slopes in order to closely mirror the infiltration,and peak elevation of the basin as designed. SEDIMENT POND Designed as PART OF A CRESCENT FLOOR AREA = 880.00 sf 3:1 Side Slopes 2.5' above floor area =2187.48 sf Volume =3712.11 cf WaterWorks FLOOR AREA = 880.00 sf W= 17.19 & L =51.18 Side Slopes 1,2 &4 = 3.1 Side Slope 3 = 4:1 Volume at 2.5' above floor =3753.9 cf Volume at 2.48' above floor =3709.8 cf Year Peak Vol WW Area 1 Area 2 Vol/Crescent 10 1.97 2666.39 880 1874.18 2651.90 INFILTRATION POND Designed as a CRESCENT FLOOR AREA = 1114.20 sf 3:1 Side Slopes 2.5' above floor area =3008.47 sf Volume =4961.27 cf WaterWorks FLOOR AREA = 1114.20 sf W= 15.368 & L =72.50 Side Slopes 1 &3 =4:1 Side Slopes 2 &4 =3:1 Volume at 2.5' above floor =4962.8 cf Year Peak Vol WW Area 1 Area 2 Vol/Crescent 'h 0.26 307.77 1114.20 1233.69 305.09 2 0.80 1097.85 1114.20 1631.00 1091.53 10 1.40 2201.45 1114.20 2095.21 2210.75 100 2.32 4444.93 1114.20 2853.52 4447.29 I 1/12/04 12 : 11 : 7 am Marley Young Engineer page 1 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm ------------------- BASIN SUMMARY BASIN ID: A NAME: 1/2 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE . . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 .24 inches AREA. . : 1 . 01 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 988 . 0000 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 0 .31 cfs VOL: 0 .12 Ac-ft TIME : 480 min BASIN ID: B NAME: 2 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 50 inches AREA. . : 1 . 01 Acres 0 . 23 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Shallow L: 200 . 00 ks : 13 . 00 s : 0 . 0200 PEAK RATE: 0 . 63 cfs VOL: 0 .23 Ac-ft TIME: 480 min BASIN ID: C NAME: 10 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4 . 75 inches AREA. . : 1 . 01 Acres 0 . 23 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE : 0 . 97 cfs VOL: 0 .35 Ac-ft TIME: 480 min 1/12/04 12 : 11 : 7 am Marley Young Engineer page 2 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm ------------------------ BASIN SUMMARY BASIN ID: D NAME: 100 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA 1 . 01PERV IMP PRECIPITATION. . . . : 6 . 75 inches AREA. . : 1 . 01 Acres 8 . 00 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 1 . 52 cfs VOL: 0 .55 Ac-ft TIME: 480 min BASIN ID: LC NAME : 10 year storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 66 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 4 . 75 inches AREA. . : 0 . 50 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Shallow L: 110 . 00 ks : 27 . 00 s : 0 . 0400 PEAK RATE: 0 . 52 cfs VOL: 0 .19 Ac-ft TIME: 480 min BASIN ID: a NAME : 1/2 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPElA PERV IMP PRECIPITATION. . . . : 2 .24 inches AREA. . : 0 . 69 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks : 27 . 00 s : 0 . 0400 PEAK RATE: 0 .39 cfs VOL: 0 .15 Ac-ft TIME: 480 min i 1/12/04 12 . 11 . 7 am Marley Young Engineer page 3 . CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm --------------------------- BASIN SUMMARY BASIN ID: b NAME : 2 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 3 . 50 inches AREA. . : 0 . 69 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks : 27 . 00 s : 0 . 0400 PEAK RATE : 0 . 72 cfs VOL: 0 .27 Ac-ft TIME: 480 min BASIN ID: c NAME: 10 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: cfs RAINFALL TYPE. . . . : TYPElA PERRVV IMP PRECIPITATION. . . . : 4 . 75 inches AREA. . : 0 . 69 Acres . Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 1 . 05 cfs VOL: 0 .39 Ac-ft TIME: 480 min BASIN ID: d NAME: 100 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . 1 .24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 6 .75 inches AREA. . : 0 . 69 Acres 0 . 55 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 85 . 00 98 . 00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 . 20 TcReach - Shallow L: 110 . 00 ks : 27 . 00 s : 0 . 0400 PEAK RATE: 1 . 60 cfs VOL: 0 .59 Ac-ft TIME: 480 min 1/12/04 12 : 11 : 7 am Marley Young Engineer page 4 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm BASIN SUMMARY BASIN ID: dbuild NAME: 100 year storm off of building SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 10 Acres BASEFLOWS: 0 . 00 cfs IMP RAINFALL TYPE. . . . : TYPElA PERV PRECIPITATION. . . . : 6 .75 inches AREA. . : 0 . 00 Acres . 0 Acres TIME INTERVAL. . . . : 5 . 00 min CN. . . . : 0 . 00 98 . 00 TC. . . . : 0 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s : 0 . 0400 PEAK RATE: 0 .14 cfs VOL: 0 . 05 Ac-ft TIME: 480 min 1/12/04 12 :11:7 am Marley Young Engineer page 5 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 gm STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. ST Description: SEDIMENT POND WDa DURING CONSTRUCT Length:Length: 51.18 ft. Side Slope 1: 3 Side Slope 3 : 4 Side Slope 2 : 3 Side Slope 4 : 3 Infiltration Rate: 7 .50 min/inch STAGE <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> STAGS <----STORAGE----> ft ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Pt- ( ) 100 00 SO 0000 0.0000 100.65 665.99 SO=0167 101.35¢ 1612 0.0370 102.00 2726 0.0626 100.05 44.525 0.0010 100.70 725.37 100.10 90.129 0.0021 100.75 785.95 0.0180 101.40 1689 0.0388 102.05 2822 0.0648 100.15 136.82 0.0031 100.80 847.77 0.0195 101.45 1768 0.0406 102.10 2920 0.0670 100.20 184.62 0.0042 100.85 910.82 0.0209 101.50 1848 0.0424 102.15 3019 0.0693 100.25 233.52 0.0054 100.90 975.11 0.0224 101.55 1929 0.0443 102.20 3119 0.0716 100.95 1041 0.0239 101.60 2012 0.0462 102.25 3221 0.0739 100.30 283.55 0.0065 0.0481 102.30 3324 0.0763 100.35 334.70 0.0077 101.00 1107 0.0254 101.65 2096 100.40 387.00 0.0089 101.05 1176 0.0270 101.70 2182 0.0501 102.35 3429 0.0787 100.45 440.45 0.0101 101.10 1245 0.0286 101.75 2269 0.0521 102.40 3536 0.0812 100.50 495.07 0.0114 101.15 1316 0.0302 101.80 2358 0.0541 102.45 3644 0.0837 100.55 550.86 0.0126 101.20 1388 0.0319 101.85 2448 0.0562 102.50 3754 0.0862 100.60 607.83 0.0140 101.25 1461 0.0335 101.90 2539 0.0583 1/12/04 12 :11:7 am Marley Young Engineer page 6 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION pROJ 2003-19 2003-19x.pgm STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct ST STAGS <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGS <-INFILTRATION- 100.0 > (ft) ---cfa-- ------- (ft) ---cfa-- ------- (ft) ---cfs-- ------- --cfa-- - 100.65 0.2204 s 101.30 0.2848 101.95 0.3560 100 0 0.1629 102.00 0.3618 100.70 0.2251 101.35 0.2900 100.05 0.1671 102.05 0.3676 100.10 0.1713 100.75 0.2299 101.40 0.2953 100.80 0.2346 101.45 0.3006 102.1 0.374 100.15 0.1756 102.15 0.3793 100.85 0.2395 101.50 0.3060 100.20 0.1799 102.20 0.3852 100.90 0.2443 101.55 0.3114 100.25 0.1842 102.25 0.3912 100.30 0.1886 100.95 0.2493 101.60 0.3168 101.00 0.2542 101.65 0.3223 102.3 0. 3972 100.35 0.1930 102.35 0.4033033 101.05 0.2592 101.70 0.3278 100.40 0.1975 102.40 0.4094 100.45 0.2020 101.10 0.2642 101.75 0.3334 155 100.50 0.2065 101.15 0.2693 101.80 0.3390 102.50 0.4217 101.20 0.2744 101.85 0.3446 100.55 0.2111 102. 0.417 100.60 0.2157 101.25 0.2796 101.90 0.3503 1/12/04 12 :11:7 am Marley Young Engineer page 7 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. Tb Description: Length: 72 .50 ft . Width: 15 .37 ft. Side Slope 1: 4 Side Slope 3 : 4 Side Slope 2 : 3 Side Slope 4 : 3 Infiltration Rate: 7 .50 min/inch STAGS <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> (ft) ---cf--- --AC-Pt- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Pt- 100.00 0.0000 0.0000 100.65 858.64 0.0197 101.30 2004 0.0460 101.95 3463 0.0795 100.05 56.480 0.0013 100.70 936.22 0.0215 101.35 2105 0.0483 102.00 3589 0.0824 100.10 114.51 0.0026 100.75 1016 0.0233 101.40 2207 0.0507 102.05 3717 0.0853 100.15 174.10 0.0040 100.80 1097 0.0252 101.45 2312 0.0531 102.10 3847 0.0883 100.20 235.27 0.0054 100.85 1179 0.0271 101.50 2418 0.0555 102.15 3979 0.0914 100.25 298.02 0.0068 100.90 1264 0.0290 101.55 2527 0.0580 102.20 4114 0.0944 100.30 362.37 0.0083 100.95 13SO 0.0310 101.60 2637 0.0605 102.25 4250 0.0976 100.35 428.34 0.0098 101.00 1438 0.0330 101.65 2749 0.0631 102.30 4388 0.1007 100.40 495.92 0.0114 101.05 1528 0.0351 101.70 2863 0.0657 102.35 4529 0.1040 100.45 565.15 0.0130 101.10 1619 0.0372 101.75 2979 0.0684 102.40 4671 0.1072 100.50 636.02 0.0146 101.15 1713 0.0393 101.80 3097 0.0711 102.45 4816 0.1106 100.55 708.55 0.0163 101.20 1808 0.0415 101.85 3217 0.0739 102.50 4963 0.1139 100.60 782.75 0.0180 101.25 1905 0.0437 101.90 3339 0.0767 1/12/04 12 :11:7 am Marley Young Engineer page 8 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct Tb STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> STAGE <-INFILTRATION-> (ft) ---cfs-- (ft) ---cfe-- ------- (ft) ---cfe-- (ft) ---cfs-- ------- 1 5100.65 0.2874 101.30 0.3764 101.95 0.4734 00.00 0.2063 100.05 0.2123 100.70 0.2939 101.35 0.3836 102.00 0.4812 100.10 0.2183 100.75 0.3006 101.40 0.3908 102.05 0.4890 100.15 0.2243 100.80 0.3072 101.45 0.3981 102.10 0.4969 100.20 0.2304 100.85 0.3139 101.50 0.4054 102.15 0.5049 100.25 0.2366 100.90 0.3207 101.55 0.4128 102.20 0.5128 100.30 0.2427 100.95 0.3275 101.60 0.4202 102.25 0.5209 100.35 0.2490 101.00 0.3343 101.65 0.4276 102.30 0.5289 100.40 0.2553 101.05 0.3412 101.70 0.4352 102.35 0.5371 100.45 0.2616 101.10 0.3482 101.75 0.4427 102.40 0.5452 100.50 0.2680 101.15 0.3551 101.80 0.4503 102.45 0.5535 100.55 0.2744 101.20 0.3622 101.85 0.4580 102.50 0.5617 100.60 0.2809 101.25 0.3693 101.90 0.4657 L 1/12/04 12 :11:7 am Marley Young Engineer page 9 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm -- --------------- STAGE DISCHARGE TABLE OVERFLOW WEIR ID No. W Description: Ratio (h:lv) : 3 .2100 Weir length: 4 . 0000 ft. El : 103 . 00 ft. Weir Increm: 0 . 05 STAGS <--DISCHARGE---> STAGS <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> ft cfs-- (ft) ---cfs-- ------- (ft) ---cfs-- ------- 103.60 8.2960 103.90 17.352 103.00 0.0000 103.30 2.5267 103.05 0.1469 103.35 3.2694 103.65 9.5703 103.95 19.200 103.10 0.4341 103.40 4.0987 103.70 10.937 104.00 21.147 103.15 0.8215 103.45 5.0151 103.75 12.397 103.20 1.3016 103.50 6.0195 103.80 13.952 103.25 1.8706 103.55 7.1128 103.85 15.603 g 1/12/04 12 :11:7 am MarleyYoung Engineer page 10 LADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL I2FI3TRATON 9TIP9m PROD 2003-19 HISTORY OF HyDROGRAPH ACTIVITY Date of Session: 1/12/04 12:10:11 am CMUMIS MOVE 8 to 1 0.3126 cfa 0.1209 ac-ft 8.00 hrs MOV$ B to 2 g,o0 hrs 0.6326 cfa 0.2327 ac-ft MOVE C to 3 0.9693 cfs 0.3511 ac ft 9.00 hro MOVE D to 4 1.5186 cfs 0.5474 ac-ft 8.00 hra MOVE a to 5 0.3937 cfs 0.1486 ac-ft 8.00 bra MOVE b to 6 g 00 hra 0.7191 cfa 0.2660 ac-ft MOVE c to 7 1.0543 cfs 0.3878 ac-ft 8.00 bra MOVE d to 8 1.5971 cfs 0.5874 ac-ft 8.00 hro LPOOL 1 "1/2" 1 5 Tb W 9 PkStg OutQ hyd Volume MatchQ PeakQ Sto Die 9 Description 307.77 cf 0.31 0.39 Tb W 100.26 0.24 1/2 LPOOL 2 "2" 2 6 Tb W 10 PkStg OutQ hyd Volume MatchQ PeakQ Sto Dis Description 1097.85 cf 0.63 0.72 Tb W 100.80 0.31 10 2 LPOOL 3 "10" 3 7 Tb W 11 out hyd Volume Description MatchQ PeakQ Sto Dis PkStg 2201.45 cf 10 0.97 1.05 Tb W 101.40 0.39 11 LpOOL 4 "100" 4 8 Tb W 12 PkSt OutQ hyd Volume MatchQ PeakQ Sto Dis g Description 4444.93 cf 100 1.52 1.60 Tb W 102.32 0.53 12 SPLIT W 1 13 17 -ft 0.00 hrs 0.0000 cfs 0.0000 ac 0.2375 cfa 0.1486 ac-ft 8.25 bra SPLIT W 2 14 18 � ' M a e 1 1/12/04 12 :11:7 am Marley Young Engineer P g CpDY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION -----___ PROJ 2003-19 HISTORY OF HYDROGRAPH ACTIVITY 0.0000 cfs 0.0000 ac-ft 0.00 bra 0.3073 cfs 0.2660 ac-ft 8.67 hro SPLIT W 3 15 19 0 00 hrs 0.0000 cfs 0.0000 ac-ft 0.3904 cfs 0.3878 ac-ft 9.17 hro SPLIT W 4 16 20 0.00 hrs 0.0000 cfs 0.0000 ac-ft 0.5322 cfs 0.5874 ac-ft 9.17 hrs REM SEDIME POND EXISTING DEVELOPMENT 10 YEAR STORM EVENT DIRECTED TO r LSTEND MOVE LC to 17 ft 8.00 bra 0.1900 ac- 0.5227 cfs , LPOOL 2 "2^ 17 17 ST W 20 Pkst OutQ hyd Volume MatchQ PeakQ StO Dis 4 Description 754.66 cf 0.52 0.52 ST W 100.72 0.23 20 2 REM TO SEDIMENT POND FULLY DEVELOPBD 10 YEAR STORM EVENT DIRECTED LSTE D LpOOL 2 "2" 7 7 ST W 20 PkStg OutQ � Volume Description MatchQ Peaks SST Dis 1.OS 1.0 ST W 101.97 0.36 20 2666.39 cf 2 End program file E:\BGENIOUS\2003-19X.Pgm STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for February 23, 2004 REVISION TO THE SITE REDEVELOPMENT for Reid Realty Site Location: 23861 NE State Route 3, Belfair, WA 98528 Section 29, T23 N, R1 W, W.M., Belfair, Mason County, WA Prepared for: Alan Cady, et al Contact Person: Alan Cady 9939 Mickelberry Road NW Silverdale, WA 98383 (360) 692-6102 Prepared by: MARLEY L. YOUNG, CONSULTING ENGINEER P.O. Box 1343 Shelton,WA 98584 (360)426-7475 Project No. 2003-19 (2003-19b, pgm) Revised January 13,2004 Revised February 23,2004 a� t Q MARLEY L. YOUNG, CONSULTING ENGINEER / P.O. BOX 1343, SHELTON, WA 98584-0959 1 Ci vi 1 Engineering l (360)426-7475 FAX (360)426-5789 Storrnwater Site Plants Sevier Extensions Marley L. Young, P.E., P.L.S. o Civil Engineer& Land Surveyor o IIIIIII�I ® I PROJECT ENGINEER'S CERTIFICATION I hereby certify that this Stormwater and Erosion/Sediment Control Site Plan prepared for Alan Cady,et al,has been prepared by me or under my supervision and meets minimum standards of Mason County and normal standards of engineering practice. 1 understand that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me. EY L. y Marley L. Young,P.E.,P.L.S. `Pea a 0TK 141/ST "lt,J� R�. e IXPiRES 3/5/0!0 Marley L.Young,Consulting Engineer Project No.2003-18 j MARLEY L. YOUNG, CONSULTING ENGINEER ?� I P.O. BOX 1343, SHELTON, WA 98584-0959 Civil Engineering (360)426-7475-(360)490-0939-Fax(360)426-5789 Stormruater Site Plans Marley L. Young, P.E., P.L.S. Sewer Extensions Civil Engineer 8 Land Surveyor o IIIII III EXPLANATION OF REVISION February 23, 2004 In response to the inter-departmental communication dated February 6,2004, and signed by Alan Tahja of the Mason County Dept. of Public Works(copy included in this report under Attachments): I) Geotechnical Testing Laboratory—Hal Parks—was employed to review and respond to the County's concerns of designing a stormwater control retention pond that would be located within fifty feet of a 15% slope. The Geotechnical Testing Laboratory report is included in this report under Attachments, and the report verifies that the slopes are stable with the pond located as designed. Other recommendations in the report regarding erosion control, filling and fill compaction have been included on the Engineer's Drawings under various Notes. 2) The Engineer's Drawings have also been updated to include an emergency overflow feature out of the retention pond. Also, finish contours have been modified to complement the emergency overflow feature. 3) The Operation and Maintenance Covenant Form now includes as Exhibit"A"a reduced 8'/2"x I I"copy of Engineer's Drawing Sheet C-2. Note: The new Engineer's Drawings are dated 2-23-04. o Marley L. Young,P.E., P.L.S. 14144 ;fr fit` L/S�E� ,•;, D(Pinl-s 3!510(c A DESIGN CRITERIA SUPPORT 2003-19b Cady The Reid Realty, Inc., building is located on property owned by the Cady family. The property has been business-oriented for at least twenty-five years. In listening to the owners of the property,they have told me that there is no stormwater sewer system,ditch system that would carry the surface water away from the property. This fact eliminated any design that included detention and surface discharge. They have also indicated that all rainwater infiltrates onsite and this onsite infiltration has been the method of natural stormwater disposal for the past twenty-five plus years, and the owners wish to continue with this preferred method of stormwater disposal. The way the total property is contoured, they do not receive stormwater from offsite sources. Two holes were drilled in the area of the proposed infiltration pond. The purpose of the holes was to determine the infiltration rate and the elevation of the ground water. The soils were identified as silty sand with a perc rate of 1.2 minutes per inch. The ground water elevation was found at 62.00+/- feet. Soils investigations determined that the ground water was within between five and six feet of the ground surface. This condition reduces the options available for onsite storage via large tanks or vaults because of the buoyancy factor. The inability to"empty" a large tank or vault reduced their desirability and efficiency. The available perc rate of 1.2 minutes per inch has been deemed by the county reviewers as too fast. The County is concerned that the stormwater would perc too quickly into the ground and surcharge the ground water and cause water problems `down stream' of the site. To reduce this concern we are proposing a retention pond for total onsite disposal by infiltration. We are also including as part of the retention pond design that the pond include an imported sand floor that will slow the infiltration from 1.2 minutes per inch to 7.5 minutes per inch. This would effectively retain the stormwater onsite and the discharge off site through infiltration would satisfy the streambank erosion control requirements of the D.O.E. Manual. The discharge offsite through infiltration would be less than the 50 percent of the calculated existing 2-year storm event discharge, and much less than the existing 10— 100 year storm event discharge. L " Alan Cady,et al—Belfair Site Redevelopment-Revised TABLE OF CONTENTS Page Engineer's Certification Design Criteria Support Table of Contents Best Management Practices(BMPs) .............................................................. 1 ........................ Large Parcel Stormwater Site Plan I. Project Overview .............................................................. 2 Minimum Requirements#1411 .............................................................. 3 II. Plot Plan .............................................................. 5 III. Preliminary Conditions Summary .............................................................. 5 IV. Off-site Analysis .............................................................. 5 V. Permanent Stormwater Quality Control Plan ....................................................... 5 Storm Event Design Assumptions .............................................................. 6 VI. Special Reports and Studies(Not Applicable to this Plan) ...................................... 7 VII. Basin and Community Planning(NA) .............................................................. 7 VIII. Permits 7 IX. Erosion and Sediment Control Plan .............................................................. 8 Minimum Requirements#1-#15 .............................................................. 9 X. Bond Quantity Worksheets (NA), Detention Facility Summary Sheet and Sketch (NA), Declaration of Covenant .............................................................. 11 XI. Operation and Maintenance Manual .............................................................. 11 Changed Conditions .............................................................. 12 ************************************************************************************* ATTACHMENTS SUPPORTING CALCULATIONS CIVIL DRAWINGS Marley L.Young,Consulting Engineer Project No.2003-19 L � REVISED February 23,2004 STORMWATER AND EROSION/SEDIMENT CONTROL SITE PLAN for Alan Cady,et al—Reid Realty Site Redevelopment,Belfair,Washington The Puget Sound Water Quality Management Plan(PSWQMP),which is administered by the State of Washington Department of Ecology, mandates that all counties and cities within the Puget Sound drainage basin adopt ordinances to control runoff from new development and redevelopments. The PSWQMP also directs local governments to adopt stormwater programs that must include minimum requirements that are consistent with the PSWQMP,and which are substantially equivalent t the DOE's Stormwater Management Manual for the Puget Sound Basin,(DOE's Technical Manual). The goal of the Puget Sound Water Quality Management Plan is to: ■ Protect and restore beneficial uses of aquatic resources, including shellfish beds,fish habitat,and other resources; ■ Prevent contamination of sediments from urban runoff, ■ Meet standards for water and sediment quality by reducing pollutant discharges from stormwater throughout Puget Sound. BEST MANAGEMENT PRACTICES(BMPs) Best management practices(BMPs)are defined as physical, structural,or management practices that, when used singly or in combination,prevent or reduce pollution of water. Specific BMPs have been developed by Ecology to control stormwater runoff(quality and quantity)for protection of receiving waters. There are three main reasons for applying BMPs before considering advanced treatment. First, it has been shown through research and experience that BMPs can significantly reduce pollutants in stormwater. Using BMPs to control localized discharges is cost effective in comparison to treating large volumes of water. Second,our lakes and streams depend on stormwater to provide adequate flow for fish habitat and water quality. Our groundwater resources also depend on stormwater for recharge. BMP implementation offers a way to discharge water back into the natural system. Third,and perhaps most important, stormwater management programs demand the conscientious use of best management practices to protect water quality. Specific BMPs that cover stormwater runoff quality and quantity have been included in Ecology's Technical Manual. Those BMPs can be divided into three basic categories, including Source Control BMPs, Runoff Treatment BMPs and Streambank Erosion Control BMPs. Source Control BMPs are designed to prevent pollutants from entering stormwater by eliminating the source of pollution or by preventing contact of pollutants with rainfall and runoff. Source controls are usually the most cost-effective because they reduce or eliminate the need for treatment BMPs. Implementing source control BMPs generally involves relatively simple and straightforward-actions. Examples of source control BMPs include erosion control(e.g.,covering disturbed soil),covering material storage areas, and eliminating illicit discharges. Marley L.Young,Consulting Engineer Project No.2003-19 I Alan Cady,et al—Belfair Site Redevelopment-Revised Runoff Treatment BMPs are designed to remove pollutants contained in stormwater runoff. These types of BMPs are the second line of defense in protecting stormwater quality. Examples of runoff treatment BMPs include infiltrated basins,bioswales and sediment ponds. Streambank Erosion Control BMPs are designed to protect stream ecosystems from erosion and sedimentation. Types of streambank erosion control BMPs include flow attenuation BMPs for reducing peak flows from a development(e.g., detention ponds, infiltration trenches),and streamside stabilization BMPs used to stabilize eroding streambanks. I. PROJECT OVERVIEW PROPOSED PROJECT DESCRIPTION: The proposal is a redevelopment of an existing commercial building site. The existing building will eventually be razed. There will be an increase in asphalt parking. Stormwater will be disposed of by onsite infiltration. LEGAL DESCRIPTION The site is within the NE '/e of the SE '/a of Section 29,Township 23 North,Range I West,W.M., Belfair, Mason County, Washington. EXISTING CONDITIONS: The Reid Realty, Inc.,building is located on property owned by the Cady family. The property has been business-oriented for at least twenty-five years. In listening to the owners of the property,they have told me that there is no stormwater sewer system/ditch system that would carry the surface water away from the property. They have also indicated all rainwater infiltrates on site and this onsite infiltration has been the method of natural stormwater disposal for the past twenty-five years,and the owners wish to continue with this preferred method of stormwater disposal. The way the total property is contoured,they do not receive stormwater from offsite sources. There are no trees on the property. A good percentage of the lot consists of existing asphalt parking and gravel parking. GENERAL LOCATION: Reid Realty, Inc., site address is 23832 State Highway 3, Belfair, WA 98528. The site is on State Highway 3, north of the Old Belfair Highway. STORMWATER AND EROSION/SEDIMENT CONTROL PLAN REQUIREMENT DETERMINATION: Projects that add 5,000 square feet or more of new impervious surface must comply with all the large Parcel minimum Requirements. A Large Parcel Erosion and Sediment Control Plan is discussed,and the necessary BMPs are included in this report. The report will review the components of the Large Parcel Stormwater Site Plan, which include the temporary erosion and sediment control necessary during construction,permanent stormwater quantity control,civil drawings and specifications,and operation and maintenance recommendations for the needed stormwater facilities. This project will comply with the following Large Parcel minimum Requirements#1 through#1 I found in Section I-2.5 of the Department of Ecology' Stormwater Management Manual for the Puget Sound Basin(the Technical manual). Minimum Requirement All: EROSION AND SEDIMENT CONTROL See Section IX,, Erosion and Sediment Control Plan(Requirements #1415). 2 Marley L.Young,Consulting Engineer Project No.2003-19 l Alan Cady,et al—Belfair Site Redevelopment-Revised Minimum Requirement#2: PRESERVATION OF NATURAL DRAINAGE SYSTEMS Natural drainage patterns shall be maintained,and discharges from the site shall occur at the natural location,to the maximum extent practicable. No surface water drainage flows through this project. Minimum Requirement#3: SOURCE CONTROL OF POLLUTION Where necessary to prevent the migration of silt during construction, the owner/contractor shall construct channels to keep overland flows away from the area under construction. If dust becomes a problem, dust control methods using water shall be employed.. If necessary to reduce tracking of mud and debris onto paved roads, the owner/contractor shall utilize a construction entrance rock pad. If required, migration-sensitive soils shall be covered with straw mulch or black plastic to prevent off-site migration of soil. The erosion control plan consists of installing a construction entrance, a sediment trap and filter fabric fence. Minimum Requirement#4: RUNOFF TREATMENT BMPS Grass Swale will be used as the method of treatment. Minimum Requirement#5: STREAMBANK EROSION CONTROL Total infiltration is on site, and infiltration rates will meet or exceed STREAMBANK EROSION CONTROL requirements. Minimum Requirement#6: WETLANDS NA— The site does not include wetlands. Minimum Requirement#7: WATER QUALITY SENSITIVE AREAS NA Minimum Requirement#8: OFF-SITE ANALYSIS AND MITIGATION NA—Total infiltration onsite; therefore, offsite analysis is not required. Minimum Requirement#9: BASIN PLANNING An adopted and implemented basin plan may be used to develop requirements for water quality sensitive areas that are tailored to a specific basin. NA—No basin plan has been established at this location. Minimum Requirement#10: OPERATION AND MAINTENANCE An operation and maintenance schedule shall be required for all proposed stormwater facilities and BMPs, and the party(or parties)responsible for maintenance shall be identified. The owner is responsible for operation and maintenance of the stormwater facilities. A "Declaration of Covenants Associated With Privately Maintained Storm Drainage Facilities", which must be recorded and submitted to Mason County as part of the approval process, has been prepared for the project. A copy of the unsigned document is included in the Attachments. Minimum Requirement#11: FINANCIAL LIABILITY Performance bonding or other appropriate financial instruments shall be required for all projects to ensure compliance with these standards. NA—Mason County has not indicated that a financial instrument will be required. 3 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised II. PLOT PLAN Engineer's Civil Drawings have been developed for the project showing the location of the improvements and the layout of the proposed Permanent Stormwater Control BMPs, and an Erosion/Sediment Control Plan to be used during construction. By reference these drawings are made a part of this report. III. PRELIMINARY CONDITIONS SUMMARY See Section I, Project Overview. IV. OFF-SITE ANALYSIS (No off-site analysis is required. See Ian. Req. 48 above) Wetlands or Water of the State This site does not contain wetlands and is not within 200 feet of any waters of the State. Analysis of the 100-year Flood This site does not contain or abut a Federal Emergency Management Administration(FEMA) identified stream and is,therefore,outside any 100-year flood plain. V. PERMANENT STORMWATER QUALITY CONTROL PLAN All storm events are collected and directed to the retention pond through a grass Swale. Emergency spill containment and control has been explained above. STORM EVENT DESIGN ASSUMPTIONS Based on DOE's Stormwater Management Manual: STORM EVENT The stormwater program Water Works(software for hydrology by Engenious Systems, Inc.)was used to model the storm flows,retention, infiltration and releases. Rain Precipitation(in.) Six-month, 24-hour Storm Event 2.24 (6-mo. @ 64%of 2-yr.) Two-year,24-hour Storm Event 3.50 Ten-year,24-hours Storm Event 4.75 Hundred-year,24-hour Storm Event 6.75 Rainfall choice IA Hydrograph SBUH** ** Santa Barbara Urban Hydrograph method DRAINAGE BASIN Indianola sandy loam(Id), 0-5 percent slopes Hydrologic Soil Group A Infiltration Rate for Pond 7.5 min./inch CN#for Impervious 98 CN#for Pervious—Landscaping/Undeveloped 85 NOTE: Given the Storm Event, Soil Type and Land Use,the Runoff Curve Number(CN#) is an indicator of the total surface and subsurface runoff. 4 Marley L.Young,Consulting Engineer Project No.2003-19 t Alan Cady,et al—Belfair Site Redevelopment-Revised POST DEVELOPMENT STORMWATER RUNOFF for 1.24 ACRES Storm Event 6-month Two-year Ten-year 100-year Pre Flow cfs 0.313 0.633 0.969 1.519 Pre Volume ac ft 0.121 0.233 0.351 0.547 Post Flow cfs 0.394 0.719 1.054 1.597 Post volume ac ft 0.148 0.266 0.388 0.587 INFILTRATION-RETENTION POND—CRESCENT SHAPE Floor Length ft 72.50 WaterWorks Floor Width ft 15.37 WaterWorks Side Slopes: 3H to 1V Infiltration Rate min./inch 7.5 TOTAL SURFACE DISCHARGE Storm Event Two-year Ten-year 100-year Post Flow cfs 0.00 0.00 000 Pond Depth ft 0.80 1.40 2.32 TOTAL INFILTRATION Storm Event Two-year Ten-year 100-year Post Infil cfs 0.307 0.390 0.532 CHECKING FOR COMPLIANCE TO STREAMBANK EROSION CONTROL Post Infil cfs 0.307 0.390 0.532 Pre Flow cfs 0.633 0.969 1.519 PERCENTAGE 2-year is less than 50% OK 10-100 years are far less than 100% OK SEDIMENT TRAP Using proposed completed conditions to calculate runoff capacity requirements. Volume capacity 1,947 cf with a depth of 1.45 feet. BIOSWALE Floor length: ft 85 Floor width: ft 3 Maximum Bioswale Slope: 2% Side Slopes: 3H to 1V Cubic Feet Per Second: 6 mo.=0.39 cfs; 100-yr. = 1.59 cfs Manning's Roughness Coefficient(n)6-mo.(n)=0.06; 100-yr.(n)=0.06 Velocity in Bioswale: 6-mo.= 1.16 fps; 100-yr.= 1.80 fps Min.Water Depth: 6-mo. =0.19 ft; 100-yr.=0.37 ft. Min.Bioswale Depth: 0.74 ft.(double the 100-yr.water depth) Refer to Supporting Calculations for further details. VI. SPECIAL REPORTS AND STUDIES Geotechnical analysis of infiltration 5 Marley L.Young,Consulting Engineer Project No.2003-19 R Alan Cady,et al—Belfair Site Redevelopment-Revised VU. BASIN AND COMMUNITY PLANNING NA VII. PERMITS Agency Permit/Approval Mason County Grading Permit IX. EROSION and SEDIMENT CONTROL PLAN Temporary Erosion Control This project includes temporary erosion control. See Civil Drawings. The disturbance to the property is minimal. The types of soils are sandy, gravelly, and do not lend themselves to migration. Erosion control will use silt fences, temporary sediment pond, and the stabilization of the construction entrance. Project Description/Existing Site Conditions Refer to Section I, Project Overview. Adjacent Areas Impacts NA—No impact anticipated because of the reduced infiltration rates. SCS Soils Description The Soil conservation Service—Soil Survey of Mason County Series 1951,No. 9,Issued September 1069, shows this property having soils type Everett gravelly sandy loam,0-15 percent slopes. Soils conditions found on the property may not match exactly the soils described by SCS. Critical Areas No critical areas have been identified on this site. Erosion and Sediment Control Measures Minimum Requirements Mason County has adopted the Department of Ecology"Stormwater Management Manual for the Puget Sound Basin. All projects that disturb more than one acre must develop a Permanent Stormwater Quality Control Plan. (Mason County Ordinance 141-97) EROSION AND SEDIMENT CONTROL REQUIREMENTS The existing soils on the site have been classified by the SCS as Indianola sandy loam(Id), 0-5 percent slopes. I feel that the erosion and sediment control system hereinafter proposed will adequately provide the necessary erosion and sediment protection. The fifteen large parcel minimum requirements specified by DOE are: #1: Stabilization and Sediment Trapping All exposed and unworked soils shall be stabilized by suitable application of BMPs. From October 1 to April 30,no exposed and unworked soils shall remain unstabilized for more than 2 days. From May 1 to September 30,no exposed and unworked soils shall remain unstabilized for more than 7 days. Prior to leaving the site,stormwater runoff shall pass through a sediment pond or sediment trap,or other appropriate BMPs. 6 Marley L.Young,Consulting Engineer Project No.2003-19 t c Alan Cady,et al—Belfair Site Redevelopment-Revised #2: Delineate Clearing and Easement Limits The clearing limits shall be defined by the owner. #3: Protection of Adjacent Properties The underlying soils have very little potential for migration. Protecting adjacent property from damage from sediment deposition does not appear to be a problem. #4: Timing and Stabilization of Sediment Trapping Measures Sediment trap and filter fabric will be placed as shown on the Civil Drawings. #5: Cut and Fill Slopes The infiltration pond shall have side slopes no steeper than 3 feet horizontal to 1 foot vertical(3:1). Other minor side slopes will be 2 or 3:1. #6: Controlling Off-site Erosion Off-site erosion is not anticipated to become an issue. #7: Stabilization of Temporary Conveyance Channels and Outlets It is anticipated that the water velocity for ground surface flows will not reach erosion velocity. All stormwater will be infiltrated on site. #8: Storm Drain Inlet Protection See Civil Drawings for storm drain inlet protection. #9: Underground Utility Construction Architectural and Civil drawings put contractor on notice as to the installation requirements of underground utilities. #10: Construction Access Routes Construction vehicles access shall be,whenever possible,limited to one route. Access points shall be stabilized to minimize the tracking of sediment onto public roads. s There shall be only one access to the site for construction purposes. See CivilDrawingfor location and detail. #11: Removal of Temporary BMPs All temporary erosion and sediment control BMPs will be removed when final site stabilization is achieved. #12: Dewatering Construction Sites Dewatering is not necessary. The soil characteristic is highly porous. #13: Control of Pollutants Other Than Sediment on Construction Sites All pollutants other than sediments that occur onsite during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. #14: Maintenance All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function. #15: Financial Liability Not Applicable to this project. Marley L.Young,Consulting Engineer 7 Project No.2003-19 Alan Cady,et al-Belfair Site Redevelopment-Revised Permanent Stabilization At the conclusion of site construction improvements,within seven days permanent site stabilization shall be completed by spreading seed and mulch on all exposed soils to establish a ground cover. Use the following recommended seed mixture for erosion control, or a County-approved alternate seed mixture. Proportions Percent Percent Name -by Wei Tqdfty Germination Redtop(Aostis alba) 10 percent 92 90 Annual rye(Lolium multiflorum) 40 percent 98 90 Chewing fescue 40 percent 97 80 (Festuca rubra commutata) (Jamestown,Banner,Shodow,or Koket) White dutch clover(Trifolium reaens) 10 percent 96 90 The following is a guide for use of recommended mulch material: Application Rates Depth Mulch Quality Per 1000 Per of Material Standards SS .Feet Acre Application Remarks Gravel,Crushed Washed 3/,to 9 CY 3 inches Good for short slope and Stone 1'/2-inch around woody plants and ornaments. Use where Subject to foot traffic. Hay or straw Air dry.Free from 75-100 lbs 1.5 to Min.2 inches Use where needed for more weed seed and pounds 2.5 tons than 3 mos. Subject to coarse material. (Approx. blowing—keep moist or 2 in.thick) 90-120 Bales When used on critical areas, Wood Fiber No growth organism 25 to 30 1000 to 1500 double application rate. Cellulose(Partly inhibiting factors pounds pounds Apply with hydromulcher. Digested wood factors. No tie-down required. fibers) Stormwater Management Considerations Please see Section V, "Permanent Stormwater Quality Control Plan"for a complete description of the stormwater management plan. Maintenance The responsibility for maintaining the facilities will lie with the owners of the property or their assigns. For maintenance recommendations please see Section XI, "Operation and Maintenance Manual"below. Calculations Calculations are briefly described in Section V, "Permanent Stormwater Quality Control Plan"above, and included in the attached Supporting Calculations. X. BOND QUANTITIES WORKSHEET,RETENTIONMETENTION FACILITY SUMMARY _SHEET AND SKETCH,AND DECLARATION OF COVENANT Bond Quantities Worksheet-NA Retention/Detention Facility Summary sheet-NA Declaration of Covenant-Mason County requires that a "Declaration of Covenants Associated with Privately Maintained Storm Drainage Facilities"be executed and filed with Mason County as part of the approval process. A copy of the unsigned document is included in the Attachments. 8 Marley L.Young,Consulting Engineer Project No.2003-19 i Alan Cady,et al—Belfair Site Redevelopment-Revised M. OPERATION&MAINTENANCE MANUAL MAINTENANCE PLAN The responsibility for maintaining the facilities will lie with the owners of the property or their assigns (e.g.,Contractor). The facilities are designed to minimize the need for extensive maintenance. MAINTENANCE OF TEMPORARY EROSION BMPs DURING CONSTRUCTION During construction the major maintenance activity is to inspect the silt fences and sediment pond. If the drainage carries mud or debris,additional silt fences should be placed in the path of the drainage to eliminate any siltation from exiting the project site. All erosion and sediment control BMPs installed shall be inspected regularly,especially after any large storm. Maintenance, including removal and proper disposal of sediment should be done as necessary. (Generally sediment that restricts the sheet flow or infiltration must be removed.) ( y MAINTENANCE OF PERMANENT STORMWATER CONTROL FACILITIES The Type 30 catch basin shall be inspected semi-yearly for the accumulation of oil and sediment. The catch basin should be cleaned with oil-absorbing materials every six months,spring and fall, if warranted. In the fall inspect the grass swale to assure that the grass will stand 4-5 inches through winter. Inspect the Swale to assure that it is clear of debris that would block flow and that the flow is spread throughout the discoloration or staining for black or brown g width of the swale. In the sprang the Swale shall be inspected caused by fluids. The stained soil and sod should be replaced and the old material disposed of in the appropriate manner. accumulation of silt that would restrict the infiltration rate,the silt If the infiltration retention pond has an , must be removed. The infiltration pond shall also be kept clean of all settleable solids and floating debris. Ideal condition is that storimwater in the pond would disappear(infiltrate)within 24 hours of a 2-year storm event. CHANGED CONDITIONS: The conclusions and recommendations in this report are based on my interpretation of site conditions,and the expectation that my onsite exploratory efforts adequately define the surface and sub-surface conditions throughout the site. In the event that the scope of the project or location of the improvements or surface/subsurface conditions differ from those I relied on in this report, I should be advised. At that time,a review of the changed conditions will be made and alternative or remedial recommendations given as requested. This Stonmwater Site Plan has been prepared by: Marley L. Yo6rih,P.E. L. . 9 Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised ATTACHMENTS Marley L.Young,Consulting Engineer Project No.2003-19 Alan Cady,et al—Belfair Site Redevelopment-Revised DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES (Copy of unsigned document) Marley L.Young,Consulting Engineer Project No.2003-19 1 � RETURN ADDRESS GRANTOR(S)(Last,First and Middle Initial) GRANTEE: MASON COUNTY DEPARTMENT OF PUBLIC WORKS DECLARATION OF COVENANTS ASSOCIATED WITH PRIVATELY MAINTAINED STORM DRAINAGE FACILITIES Declaration of Covenant In consideration of approval of the development known as ,relating to real property legally described as follows: County Assessor's Property Tax Parcel Numbers 12329 4100090& 00091 See Attached EXHIBIT"A" The undersigned, as owner(s),covenant and agree that: 1. If at any time Mason County reasonably determines that maintenance or repair work is required to be done to the existing,approved storm drainage facilities installed on the property described above and located outside of any public right of way(which will mean repair and/or clean out of the existing system only to the same standards as originally installed and approved),the Director of the Department of Public Works shall give the current owners seven days notice that the County intends to perform such maintenance or repairs,or to have them performed by others. If the current owners have not completed or are not diligently pursuing the repair or maintenance of the system and it becomes necessary for Mason County to perform the work,the current owners will assume responsibility for the cost of such maintenance or repair and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments,and any costs or fees incurted by the County,should any legal action be required to collect such payments,will be borne by the parties responsible for said reimbursements. I�- 2. If at any time Mason County reasonably determines that the existing and approved storm drainage system on the property poses a hazard to life and limb, or endangers property, or adversely affects the safety and operations of a public way,due to failure,damage or non-maintenance of the existing on-site storm system,and that the situation is so adverse as to preclude written notice to said owners,the Director of the Department of Public Works may take the measures necessary to eliminate the hazardous situation (which will mean repair or clean out of the existing system only to the same standards as originally installed and approved)provided the Director has first made a reasonable effort to locate said owner before acting. The current owners will assume responsibility for the cost of such maintenance or repair;and will reimburse the County within thirty days of receipt of the invoice. Overdue payments will require payment of interest at the current legal rate for liquidated judgments,and any costs or fees incurred by the County, should any be borne by the parties responsible for said reimbursements. 3. The owner shall keep the Mason County Public Works Department informed at all times as to the name, address and telephone number of the contact person responsible for the performance of maintenance or repair work to the storm drainage facilities. These covenants are intended to protect the value and desirability of the real property described above,and to benefit all the citizens of Mason County. They shall run with the land and be binding on all parties having or acquiring from the current owners or their successors,any right,title or interest therein, and to the benefit of all the citizens of Mason County. Signature Signature Owner Owner Address Address City, State,Zip City, State,Zip Phone: Phone: STATE OF WASIIINGTON ss. (INDIVIDUAL ACKNOWLEDGMENT) County of MASON Notary Public in and for the State of Washington,residing at do hereby certify that on this day of ,200_,personally appeared before me to me known to be the individual described in and who executed the within instrument and acknowledged that signed and sealed the same as free and voluntary act and deed for the uses and purposes herein mentioned. GIVEN UNDER MY HAND AND OFFICIAL SEAL this day of , 200_. Notary Public in and for the State of Washington,residing at in said County. My Commission expires REDEVELOPMENT OF AN EXISTING SITE S CADY, ET AL. OFFICE 8UILDINC AT 23861 NE STATE ROUTE 3. BELFAIR, WA 98528 I = IN A PORTION OF THE NE114 OF THE SE114 OF SECTION 29,TOWNSHIP 23 NORTH,RANGE 1 WEST.W.M.LOCATED IN BELFAIR leI PERMANENT STORMWATER CONTROL INCLUDING STORM DRAIN PIPES 2•lB CRT— Q r, o W. R:"e'rr�w ;LE-.Elk" w I I r lm)o r+zT iRiw eNc a cOPCR fra r. u.•awo.'+,r --I `a5 I wIEN BAVNapt KUo 4 RN[LEY ITEM I raw ROOF piMNi IlE(OUT)63 V E (A flA $ WIT 4-6 D-3G,4 Pvc -•L•o:r aOPC t�� «• l T)SCµCR Biaa7VPEVroAR D L � EMIWG WATER ME J O• S'U.BE U6[D TC U"NON BULDIIG }p o yb' �.l E'll"I BNLWG-� / cG.77 u 1MK CCH+14Ud15 Via' GIov ALE,z g lER X ReTrE )'t SR D r;aAN. F�� iaRsrwc+wN. \ /r ' ^* � r �• yr, To"DRMN ` k"vI M1?60 {LEAN out _ wb rA o FIRST FLOOR "Er"E P c e s.L.. — 4"1';� +.RS r c+st�uli rout a col[R oowr U' ` vr' ELEV. 69:53 .r1 Nc NUI Pa RfG AIERµS 5 N'o'°"r s.' r <, IW Rod pubs �� rECE55ARr 65 u DRAJI INLET CATCH 019N E $ GRATE Pito7 ON TMF.RN CPIAST`CWRPE Misia � � uStµl a'6 � ' �C•IE r �� i �Rcan r Rmom z `�' I AS NECESSARY . a,v'A ( r-iv.,o°wrn: r axr.oRR.w,r rRd rnl ur..svr4 Pr.wr °�iiv lxa.Ro am. � �$ I ' '6j`.q.6 I ai°'.[� ,i'Oj• \ w�^'^ ar«�n.r 4•P...•T v...0 .I .-WE f 61 E SLOIL / BUICRIG MfST \ 6'•6'.r•4+vrt Rr ■■11 CArrR DAv l 1 // RAA C.I. Yrn+• a� Cpp 161u ELEV!6 rIJ '/' S[T[R 5[RN(E W.I., 4•o.r dwr •Pw.R,Av i :11 i IC(MI})FI 4! cEW LlrrUrnOrl \ ,R.A<mr rrr Nr rxl y y) Xi [( 66,D I r/ wE]O REID RCAF IV BUILDING U I( J� ^Alta BASH TO I#REMOVED TVPICAI DF.TAII,OF RODi[XWePOVT F g MN ELEr.6a60 rrn4R ILOM EI.-104; \ £C.E IECTCR ATID CLEAN(%IT i t I[(dr11 66)0 AT IRCx,COOR \ R{x)1 Simi �op To 1' -aSPµ )• 6Aa44//• a b [ Rgrr Cr D.IRr SgLn•r .ro too", piARRY aS 0 PAM 2� ,� � o3yy ylQ�B QUARRY 6R415 F y r lD 6•uAN—� �/� v,,�x„ ..TAM , u.r»n«. ��53� T ' nPlc<L cRoss secncr a raElErmrnPao ;;�(,;{'(�,rSP. �\■ ANp SAND ttOCH STABILIZED CONSTiWCT ON ENTRANCE • _ py MASONCOUNTY =0,fER&WILUAM& PUBLIC WORKS DI ECTOR/COUNTY ROAD ENGINEER ARCHITECTS Sh&00.W-hipgo.98SV DATE: December 26h, 2003 INTER-DEPARTMENTAL COMMUMCATIONS TO: Rick Mraz,DCD-Planner FROM: Alan A- Tahja,P/W-Co.Hydr.Engr_ WOW PLG-03 SUBJ: Stormwater Site Plan (SSP) NAME: Cady Offiice$ld - Belfair {tQMa003-007 97 Rick, The Stormwater Site Plan (SSP)prepared for the proposed commercial developmentfredevelopment of the Cady Family/Reid Realty property in Belfair,has been received and reviewed by Public Works. Total infiltration of storm events through a 100 year 24 hour event is promoted as the main destination for collected stormwater runoff. The proposed infiltration gallery is proposed to be preceded by a water quality treatment Swale sized to provide treatment for Ecology's Water Quality Design Storm event. The engineer who developed the stormwater site plan has indicated that offsite analysis and mitigation is not necessary due to the intended infiltration of collected stormwater runoff_ Normally offsite impacts are not anticipated from sites which are able to infiltrate their stormwater runoff,but the urbanized area of Belfair in which the subject property is located in, has existing problems with a high groundwater table, and wet surface conditions in the down- gradient properties from the Cady property_These existing problems raise the need to ascertain potential surface and sub-surface flows and impacts. Since the high groundwater table problems have been brought to the County Engineer's attention, stormwater features m the general urban Belfair area have been required to employ detention facilities instead of or m concert with retention facilities. Since the Cady property has no apparent surface discharge location,other than sheet flow to neighboring properties or infiltration,it seems apparent that infiltration is almost the only method available short of developing a storm sewer route to an acceptable disposal location. Since infiltration appears to be the most practical and financially appealing stormwater disposal practice, limiting the infiltration rate seems a logical solution to diminishing down-gradient property groundwater problems. If an infiltration facility is pursued as part of the final design, soil exploration information F11a: S:kWPX St=+*trkReviewa X Cady-Reid Real ty.doc I to be determined in accordance with Ecology's g,and infiltration rates will need et Sound Water Quality Authority's StDrmwater reportmTechnical Manual Procedures(See the Puget C ter II1_3). Techni ent Manual for the puget Sound Basin version 1992, �P ley Young,P.E.),and with Jerry Hauth, with the project engineer(M recommend I've discussed these issuee�only report at this time that Public Works cannot and site ply Detaining runoff from the developed the County Engineer'currently proposed stomnII to be a likely approach to a�ptance of the char a prescribed rate currently appeals erosion Control site and infiltrating it onsitertm pff Infi]trating water runoff a down. . tential fang of site developed as a potential Infiltration.rate,but determining Po on facWty Is ex�eCted to be addressed in the Stormw er Site discharge rate has been discussed is(acts from a detention-lnfiltrali Plan as a potential offsite impact on 451 if you have any questions regarding these please feel free to contact me at Co""r3 me lon or atte>rtion comments, or if you feel any features need ftuther S' cerely, A an A. T'a1�a Lq i 8 - o°h 2-�� C LD File: H:\WP15t�o"tr\Reviews\Cady-geld Eea2ty-doc FROM = GEOTESTLRB VHUNt NU. = 3t71a(z)44t34G IYW. "JEOTEC�CAL TESTING-LABORATORY MAMvy YOUNG CONSImL'TwG ENGRW" p. O.Box 1343 SHELTON,WA 98s84 nd BC Pent.tes�isg for noifilttt Po Reid Realty,Belfair,WA Gentlemen: o�_ The sod. Three pert holes were dug for iufiltrhion testing on Nov_7,2003 for the above em th Bced used smic is to be ;nhttFstian�ssific�tion was Type A The p�c rate for Hale#Z.in the area where the proposed located was 12 minutes per inch the test results,the to be of service to you if you have any questcons concerning Thank you for this Opportunity lease CO an ns at(36�)754-4612. pmooedures used,or ifwe can be of any �'� p gesgec f dly Submitted, GsOTECWUCAL I'ESMG LABORATORY !Y Harold Parks, Engineering Geologist looll InumbCS9 Street SW, 'WA 9"12 p}mc#:(360)754A6E2 Fax A(360)754-4M rrcui i t]Cu 1 CJ I AL TESTING LABORATORY GEQTEC�C FACSU&LE TRANOWT TAL Sl�T TO: M FROM: COMPANY: DATE: FAX NUMBER: TOTAL NO.OF PAGES INCLUDING COVER PHONE NUMBER SENDERS REFERENCE NUMBM- RE: 9 YOUR REFERENCE NUMBER: Q URGENT iEI'FOR REVIEW PLEASE REPLY ❑PLEASE COMMENT NOTESICOMMENTS: 10011 BLOMBERG ST.SW OLYMPM WA 98512 PHONE#: (360)754-4612 FAX#- (360)754-4848 i Os•rrw• ■ ° �• \ wl.�s•x /• 1.n YM•-� I ��. u•YYww•• / /ter"' + Fi!� s1;', LF 00 ji twa <<' �,•• wtt I Ra1,....,.., _ ,, '°"`o.. .s , ' �s • ;° Yy,'' :5r'%`lw. 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Pale 3 Page#1 of 1 GEOTECHNICAL TESTING LABORATORY MARLEY YOUNG P.O. Box 1343 SHELTON,WA II Re: Reid Realty Sample from Peninsula S&G Gentlemen: Constant Head Permeability testing was performed on Samples 1 and 2 of material picked up Jan. 7, 2004 from Peninsula Sand& Gravel. The results are as follows: Sample#1: 3.0 x l W3= 14.1 min/in Sample#2: 7.2 x 10-3=5.88 min/in If you have any questions concerning the test results,the procedures used,or if we can be of any further assistance please call on us at (360)754-4612. Respectfully Submitted, GEOTECHMCAL TESTING LABORATORY 1 Harold Parks Engineering Geologist 10011 Blomberg Street SW,Olympia,WA 98512 1 MASON COUNTY PUBLIC WOKKS DIRECTOR/COUNTY ROAD rWGME-ER Sh*0a W6A1Rt,985M TNTCR-DEPARTMENTAL COMMMCATIONS DATE---.Febr 6m 2004 TO: Rick Mraz, DCD-Planner FROM: Alan A_ Tahja,P/W-Co_Hydr•Engr. WO#PLG-04 SUM. Stormwater Site Plan (SSP) NAME: Cady/Reid Realty Office Bldg Reiftir The revised Stormwater Site Plan(SSP)preps for the proposed redevelopment of the comrQ=ial Cady Family/Reid Realty property in Belfair,has been received and reviewed by Public Works. Fve had several discussions with Marley Young,P.E.,regarding design approaches,and have discussed the current plan with Jerry IH'attth, and feel I can recommend acecptance of the revised stormwater site plan subject to a couple of minor revisionsladditions to the praposaL The infiltration pond proposed in the design is located less than 50 feet from a steep(> 15%) Slope. Since the proposed location is less than Ecology's minimum setback distance from the slope,a geotechnical report addressing the potential impact of a wet pond on a steep slope should be required to be preparod and submitted to the County for review and comments. The second issue raised by Public Works' review is the need to incorporate an emergency overflow feattue on the retention pond. I've discussed these two issues with Mr, Young,who felt both could be addressed to the County's satisfaction. Included in Mr. Young's SSP narrative is a copy of an Operation and Maintenance(O&m) Coven=Form(blank).The Covenant foam needs to be appropriately Shed out,tworded with the County Auditor's Office, and a copy of the recorded instrument delivered to Public Wodcs for monitoring and administmdon. Pve requested that when the O&M Covenant is preps for recording,that a copy of the Permanent StormwRter Control Plan(Sheet C2)be recorded with the covenant. Subject to the issues relating to a pond overflow,geotechnical investigation,and inclusion of a portion of the SSP into the O&M Covenant,Public Works considers the proposed Stagywater Site Plan to be acceptable and appropriate for the redevelopment of the subject property. Please feel free to contact me at County extension 461 if you have ony*questions regarding these comments,or if you feel any features need further discussion or attention_ site: Ft:1rwlstmm.trixerlews%Cact►-J?aid Foeicy-�.doc 74 III Geotechnical Report 23861 NE State Route 3 Parcel #123294100090 Prepared for Marley Young Shelton, Washington by I Geotechnical Testing Laboratory Olympia, Washington February 23, 2004 GEOTECHNICAL TESTING LABORATORY MMMEY YOUNG P.O. Box 1343 SHELTON,WA 98584 Re: Geotechnical Report 23861 NE State Route 3 Parcel123294100090 N47027.146' W 122°49.538' INTRODUCTION This report summarizes the results of our geotechnical consulting services for the proposed development located at the above-mentioned site in Belfair,Washington. The location of the site is shown relative to the surrounding area on the Vicinity Map, Figure 1. Our understanding of the project is based on our discussions with you and our explorations and review of the site. We understand that the site is to be redeveloped with commercial buildings. The site is accessed by a driveway from State Route 3. In general,grading will consist of the excavation of the stormwater ponds,parking facilities, foundations, and footings. The site slopes toward the north and northwest. The steepest slope measured onsite was in excess of 15 percent, located along the western property line. Off the property to the west is an eight-foot retaining wall with minor groundwater seepage along the base. Therefore,Mason County requires that a geotechnical report be prepared in accordance with the Critical Areas Ordinance. The purpose of our services is to evaluate the surface and subsurface conditions at the site as a basis for providing geotechnical recommendations and design criteria for the project and to satisfy the requirements of the Mason County Critical Areas Ordinance. Geotechnical Testing Laboratory is therefore providing geologic and hydrogeologic services for the project. Specifically,our scope of services for this project will include the following: 1. Review the available geologic,hydrogeologic, and geotechnical data for the site area. 2. Conduct a geologic reconnaissance of the site area. 3. Investigate shallow subsurface conditions at the site by observing the exposed soil and reviewing published well logs. 4. Evaluate the landslide and erosion hazards at the site per the Mason County Critical Areas Ordinance regulations. 10011 Blomberg Street SW, Olympia,WA 98512 1 Phone#: (360)7544612 Fax#: (360)7544848 J GEOTECHNICAL TESTING LABORATORY 5. Provide geotechnical recommendations for site grading including site preparation, subgrade preparation,fill placement criteria(including hillside grading),temporary and permanent cut and fill slopes,drainage and erosion control measures. r A SITE CONDITIONS SURFACE CONDITIONS The proposed building site is located in an area of commercial development in the Puget Sound glacial upland east of the Hood Canal. The site is bordered on the southeast by State Route 3. We conducted a reconnaissance of the site area on February 9, 2004. Building site elevations range from approximately 62 to 77 feet. The building site has vegetation indigenous to the Northwest. The vegetation includes blackberries, Scot's broom, grasses, alder trees,and fir trees. At the time of the site visit,we observed no evidence of surface erosion. No evidence of deep-seated slope instability was observed on the site slopes or areas adjacent to this site at the time of our investigation. Evidence of surface water flow was not observed in the site area at the time of our reconnaissance. The general topography of the site area indicates that drainage flows toward the northwest. Seepage was observed offsite along the base of the western retaining wall. Standing groundwater was observed in three test pits at approximately 2 feet below the ground surface. 10011 Blomberg Street SW, Olympia,WA 98512 2 Phone#: (360) 754-4612 Fax#: (360)754-4848 _ I GEOTECHNICAL TESTING LABORATORY SITE GEOLOGY The site is generally situated within the Puget Sound glacial upland. The existing topography, as well as the surficial and shallow subsurface soils in the area,are the result of the most recent Vashon stade(stage)of the Fraser glaciation that occurred between about 10,000 and 12,000 years ago, and weathering and erosion that has occurred since. A description of the surficial soils is included in the"Site Soils"section of this report. In general,the soils on the site are predominantly represented by Vashon glacial till. SITE SOILS The Soil Survey of Mason County, USDA Soil Conservation Service (1960)has mapped the site soils as an Everett gravelly sandy loam, 5 to 15 percent slopes (Eh). The Everett soils are described as very deep, somewhat excessively drained,pale-brown gravelly soils. They occur as inextensive gravel ridges on the glacial moraines, or,more commonly, as fairly continuous outwash channels between ridges of Alderwood soils. They have developed upon assorted glacial till and outwash material. Permeability is rapid(up to 20 inches per hour)with a high rate of water transmission. These soils are typically classified as a"Group A" relative to surficial runoff. The soils are further characterized as having medium runoff potential and moderate water erosion potential. The water capacity for plants is low. Shrink-swell potential is described as low due to the low organic content. The Coastal Zone Atlas, Volume 9, Mason County(MA-11)maps the site as having Vashon Till (Q,)throughout the site. The till is a tough, dense material of low permeability. It provides excellent foundation support. The site is described as "stable." SUBSURFACE EXPLORATIONS Subsurface conditions at the site were evaluated by observing the exposed building site soil and reviewing available well logs. Gravelly sandy loam was observed to a depth beyond the scope of the project. 10011 Blomberg Street SW, Olympia,WA 98512 3 60 754-4848 Phone#: (360) 754-4612 Fax#. (3 ) GEOTECHNICAL TESTING LABORATORY SUBSURFACE CONDITIONS In general, undisturbed dense gravelly sandy loam with areas of occasional fill was observed throughout the site. Groundwater was observed in three test pits at approximately 2 feet below the ground surface. Groundwater seepage was also witnessed along the base of the retaining wall on the adjacent parcel to the west. Based on the site topography and the nature of the near surface soil, seasonally perched groundwater conditions are expected during periods of extended wet weather. Irk Seepage P ater ' S Point �ge SLOPE STABILITY Slopes in excess of 15 percent were observed onsite. Since a proposed infiltration pond is proposed within 50 feet of the slope exceeding 15 percent, Mason County requires that a geologic hazards report be completed according to the Critical Areas Ordinance. The Relative Slope Stability of the Southern Hood Canal Area, Washington, (1977)describes the site area as Class 1. Class 1 is expressed as, Areas believed to be stable. Slopes generally less than 15 percent, but may be greater locally in areas too small to be shown at the map scale. Largely comprises rolling uplands underlain by very stable material such as young glacial till, mantled in places by a thin layer of sandy gravel or other permeable material; also includes flood plains, deltas, alluvial fans, and some beach deposits. Class I areas immediately adjacent to steep slopes of class 3 areas may be threatened by potential landsliding. Normal,proper engineering practices generally are adequate to insure stability in these areas. The near-surface gravelly sandy loam soils are in a dense to very dense condition except at the ground surface. The surficial soils are generally in a medium dense condition. In general,the undisturbed native soils of the site consist of a mixture of variable amounts of gravel, sand,and silt. These soil materials are in a dense condition except where they have been disturbed by weathering activity. These soils are generally stable relative to deep-seated failure. No evidence of deep-seated landslide activity was observed at the site at the time of our investigation. Weathering and erosion are natural processes that can affect steep slope areas. Instability of this nature is typically confined to the upper weathered or disturbed zone,which has been disturbed and has a lower strength. Evidence of minor surficial erosion, raveling and sloughing was not observed on the sloping areas during our investigative visit. 10011 Blomberg Street SW, Olympia,WA 98512 4 Phone#: (360) 754-4612 Fax#: (360) 7544848 I GEOTECHNICAL '1TESTING LABUKA i vn Y Significant weathering typically occurs in the upper 2 to 3 feet and is the result of oxidation, root penetration, wet/dry cycles, and freeze/thaw cycles. Erosion in steep slope areas such as this can be reduced by encouraging vegetation and discouraging runoff from the steep slope. Erosion control recommendations for the sloping areas are provided in the"Erosion Control'section of this report. CONCLUSIONS AND RECOMMENDATIONS GENERAL Based on the results of our site reconnaissance and subsurface observations,and our experience in the area, it is our opinion that the site is suitable for the proposed commercial structure and stonnwater pond. The slope is stable relative to deep-seated instability and will not be affected by the proposed commercial structure and stormwater pond. Proper drainage control measures will reduce or eliminate the potential for erosion and improve slope stability. Deep-seated instability is not expected to affect the commercial structure and stormwater pond. In general,the site soils are not suitable for use as structural fill material. Since saturated soil conditions may be associated with these soils during or following extended periods of rainfall,we recommend that earthwork be undertaken during favorable weather conditions to reduce grading time and construction costs. If our analysis and recommendations are followed,we do not anticipate any on site or off site impact from the proposed construction. It is our conclusion that potential landslide hazards can be overcome so as not to cause harm to property,public health and safety,or the environment. Pertinent conclusions and geotechnical recommendations regarding the design and construction of the commercial structure and stormwater pond are presented below. f LANDSLIDE—EROSION HAZARD AREAS Classification The Mason County Critical Areas Ordinance(17.01.100)defines a landslide hazard area as one containing slopes equal to or greater than 15 percent with springs or groundwater seepage. Site slopes exceed 15 percent and groundwater seepage is apparent along the base of the neighboring retaining wall. Based on this,this site does meet the technical criteria of a landslide hazard. 10011 Blomberg Street SW, Olympia,WA 98512 5 Phone#: (360)7544612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY The Mason County Critical Areas Ordinance(17.01.104)defines an erosion hazard area as: Areas in Mason County underlain by soils which are subject to severe erosion when disturbed. Such soils include, but are not limited to, those for which potential for erosion is identified in the Soil Survey of Mason County, USDA Soil Conservation Service, 1960, or any subsequent revisions or additions to this source. These soils include, but are not limited to, any occurrence of River Wash ("Ra') or Coastal Beaches ("Cg') and the following when they occur on slopes 1 S%or steeper: a. Alderwood gravelly sandy loam ("Ac"and "Ad') b. Cloquallum silt loam("Cd') c. Harstine gravelly sandy loam ("Hb') d. Kitsap silt loam ("Kc') The soils at the site are mapped as Everett gravelly loamy sand(Eh). This site does not meet the technical criteria of an erosion hazard area. Slope Stability Based on our field observations,explorations,and our experience with the soil types encountered on the property, we conclude that although portions of the neighboring slopes exceed 100 percent,they are generally stable relative to deep-seated failure in their present configuration. A building setback from landslide hazard areas is required unless evaluated and reduced by an engineering geologist or a licensed professional engineer. Based on our geotechnical evaluation of the site and our experience in the area, a building setback will be needed for this lot. We recommend a setback distance for the retention pond of 15 feet m the bottom of the and to the face of the The setback may be measured from p f e western slope. e from the top o the p Y slope. The following figure represents a shear angle for the site soils. Shear angle and cohesion are variables used to model the site. Peak Shear Stress vs. Normal Stress Gravelly Sandy Loam 3000 39" 2500 C' a 2000 N 1500 A d s N 1000 d a 500 —♦-1/4 ton —411--1/2 ton — -1 ton 0 0 500 1000 1500 2000 2500 3000 Normal Stress (pst) 10011 Blomberg Street SW, Olympia,WA 98512 6 Phone#: (360)7544612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY Slope stability was modeled using the GEO-SLOPE/W program(version 5.13)in both static and dynamic conditions Slop e Realty p (ca=0.3). Factors of safety were determined using Bishop's, Analysis Method: Morgenstern-Price Janbu, and the Morgenstern-Price methods. Three cross- Direction of Slip Movement:Left to Right sections were modeled for the site. The site geology was Seismic Coefficient: Horizontal and Vertical modeled using a retaining wall and a monolithic layer of l gravelly sandy loam. The soil was determined to have a unit l weight of 128 pcf,cohesion of 500 psf, and a shear angle of 39°. Conservative soil values were used in the model, unit weight of 128 pcf,cohesion of 250 psf,and a shear angle(�) of 20°. Under static conditions,the slopes remained stable to deep-seated and shallow failure. Under dynamic loading,the . 2816 computations demonstrated that the slope is not . susceptible to surficial raveling; large deep-seated failure was 88 °' 82 i not demonstrated by our model. The following figures 78 illustrate a moment F.S. over 1.00 under dynamic conditions. 74 The following solutions are the lowest factors of safety 70 0 generated b the models for the three cross-sections. > 62 — vei g y w 68 soil Modet 64 u�Welylt:126 Cohesion:250 Reid Realty 48 :2 Slope B 3 0 5 10 15 20 25 30 35 40 45 50 55 W 65 70 75 Analysis Method: Morgenstern-Price Distance(ft) Direction of Slip Movement: Left to Right Seismic Coefficient: Horizontal and Vertical Reid Realty Slope C Analysis Method: Morgenstern-Price is Direction of Slip Movement. Left to Right . Seismic Coefficient: Horizontal and Vertical ss r 92 C8800 : 74 76 . . . ' 70 > 72 v ss Lll \\ c 62 —EvveTet-sell--- •� 6 Sol Model:Mohr-CouTom _ 64 N > lh►lt Weight 128 I ure 2 60 54 Cohesion:250 ao LU 51 i:2 -5 0 5 10 15 20 25 30 35 40 45 46 o s w 15 20 25 30 35 40 4; 50 se o0 65 70 75 eo Distance(ft) Distance(ft) Slope C is modeled using a retaining wall, shown as a blue wedge. For all three profiles,the groundwater table is represented by the dashed blue line. Changes in slope stability are not expected to result from minor excavations in the development of the site. Grading in the building portion of the site should be conducted in accordance with geotechnical recommendations provided herein. 10011 Blomberg Street SW, Olympia,WA 98512 7 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY As previously discussed,weathering, erosion, and the resultant surficial sloughing and landsliding are natural processes that affect slope areas. Significant weathering typically occurs in the upper 2 to 3 feet and is the result of oxidation,root penetration,wct/dry cycles and freeze/thaw cycles. No significant surficial raveling or sloughing was observed in the natural(undisturbed) sloping portions of the site. To manage and reduce the potential for these natural processes,we recommend the following: 1. No drainage of concentrated surface water or significant sheet flow onto the slope area. 2. No filling within the setback zone unless retained by retaining walls or constructed as an engineered fill. SEISMIC—LIQUEFACTION HAZARD According to the Seismic Zone Map of the United States contained in Figure 16-2 of the 1997 UBC (Uniform Building Code),the project site is located within Seismic Risk Zone 3. Based on the subsurface conditions observed at the site,we interpret the site conditions to correspond to a seismic Soil Profile Type SD, for Stiff Soil,as defined by Table 16-J (UBC). This is based on the range of SPT(Standard Penetration Test)blow counts and/or probing with a %2-inch diameter steel probe rod. The shallow soil conditions were assumed to be representative of the site conditions beyond the depths explored. Based on our review of the subsurface conditions,we conclude that the site soils have a low susceptibility to liquefaction. The near-surface soils are generally in a dense condition and the static water table is located near the ground surface. Shaking of the already dense soil may produce a denser configuration and subsequently excess pore water pressures are not expected to be produced. EROSION CONTROL It is our opinion that the potential erosion hazard of the site is not a limiting factor for the proposed commercial structure and stormwater pond. Removal of natural vegetation on the slopes should be minimized and limited to the active construction areas. Landscaping around the proposed building location is permissible,but understory growth on the slopes should be encouraged as much as possible as a deterrent to erosion. Temporary and permanent erosion control measures should be implemented and maintained during construction and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential receiving waters. Erosion control measures should include,but not be limited to, silt fences,berms and swales with ground cover/protection in exposed areas. Any re-contouring of the site will create a need for erosion control measures as listed above. Erosion control plans shall be provided by the project engineer. EARTHWORK Site Preparation All areas to be excavated should be cleared of deleterious matter including debris,and vegetation. Based on our explorations,we estimate that most clearing has already been performed. 10011 Blomberg Street SW, Olympia,WA 98512 8 Phone#: (360)7544612 Fax#: (360)7544848 GEOTECHNICAL TESTING LABORATORY Where placement of fill material is required,the exposed subgrade areas should be cleared of deleterious material to a firm and unyielding surface prior to placement of any fill. Any soft,loose or otherwise unsuitable areas delineated during construction or probing should be compacted, if practical, or over-excavated and replaced with structural fill, based on the recommendations of our site representative. Fill The fill for berms placed above the ground surface(if designed)should be placed in horizontal lifts of appropriate thickness to allow adequate and uniform compaction of each lift. Fill should be compacted to at least 90 percent of MDD(maximum dry density as determined in accordance with ASTM D-1557)to within 2 feet of subgrade and 95 percent MDD in the upper 2 feet. The appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We recommend that the appropriate lift thickness be evaluated by our field representative during construction. The suitability of material for use as fill will depend on the gradation, moisture content and permeability coefficient, required by the design engineer,of the soil. As the amount of fines (material passing No. 200 sieve)increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult to achieve. Material placed for fill should be free of debris,organic matter,trash and cobbles greater than 6 inches in diameter. The moisture content of the fill material should be adjusted as necessary for proper compaction. Suitability of On-Site Soils as Fill On-site soils may be considered for use as fill. In general,the native soils(loamy sand)encountered on the site should have more than 10 percent fines (material passing the US No. 200 Sieve). Site Drainage Surface water runoff should be controlled by a system of curbs,berms,drainage swales,and/or catch basins and prevented from flowing on the steep slope or the fill slopes. Site drainage plans shall be provided by the project engineer. LIMITATIONS We have prepared this report for the use of Marley Young and members of his design team,to use in the design of a portion of this project. The data used in preparing this report,and this report, should be provided to prospective contractors for their bidding or estimating purposes only. Our report,conclusions and interpretations are based on data from others and our site reconnaissance,and should not be construed as a warranty of the subsurface conditions. Sufficient consultation with our firm during construction should continue,to confirm that the conditions encountered are consistent with those indicated by our observations,to provide recommendations for design changes should the 10011 Blomberg Street SW, Olympia,WA 98512 9 Phone#: (360)754-4612 Fax#: (360)7544848 ' GEOTECHNICAL TESTING LABORATORY ' conditions revealed during the work differ from those anticipated,and to evaluate whether earthwork and foundation installation activities comply with our specifications. IThe scope of our services does not include services related to environmental remediation and construction safety precautions. Our recommendations are not intended to direct the contractor's methods,techniques, sequences or procedures,except as specifically described in our report for consideration in design. If there are any changes in the loads,grades,locations,configurations or types of facilities to be constructed,the I conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications,as appropriate. Respectfully, GEOTECHNICAL TESTING LABORATORY Ia: y Ama k4l� IHarold Parks,L.G.,L.E.G. Senior Engineering Geologist I � 8�7 a,8ed GO��o 1D PARK" 10011 Blomberg Street SW, Olympia,WA 98512 10 Phone#: (360)754-4612 Fax#: (360)754-4848 _J �1► � 1 art, 5 91 p2al FAA Al ;66 a'; ".r.-�'�1rJf�::.�yi!'3�lJ,i/lrll� i: � '!)itllif�/1[►�L�Jll. '+/ IN 11 to Geotechnical S 88'18, W 351.2 (REC) Testing S 87'15'14" E 364.52 (CAL( Laboratory '�—H2O o Geotechnical Services QA/QC Services Testing Services 10011 Blomberg St.SW t Olympia,WA 98512 Q ��• ''•-�+ !•- �••�! '`• Phone:(360)754-4612 Fax:(360)754-4848 O� 't:x { : r:4�•! ~� fyti• • Date: 02/15/2004 h<<f 4: at �: • •+;_; Designed by: MLY `p • •• Drawn by: MLY ' �•;! Checked by: LL ON Dwg#:02-15-04-010 O v •�, �` r' jI' O ,�O 20 PROJECT NAME: REID REALTY SITE 23861 NE STATE ROUTE 3 PARCEL 123294100090 i"=20' Revisionx 60q r y�; �: .R,';ti•h..� t•• SCALE:1 Inch=20 feet FIGURE 2 Alan Cady,et al—Belfair Site Redevelopment-Revised SUPPORTING CALCULATIONS Marley L.Young,Consulting Engineer Project No.2003-19 POND DESIGN The computer program, WaterWorks, uses rectangular trapezoidal basins for the retention/detention facilities analysis. When designing a basin,other than rectangular,the WaterWorks trapezoidal basin must be modified by length,width,and side slopes in order to closely minor the infiltration, and peak elevation of the basin as designed. SEDBIENT POND Designed as PART OF A CRESCENT FLOOR AREA = 880.00 sf 3:1 Side Slopes 2.5' above floor area =2187.48 sf Volume =3712.11 cf WaterWorks FLOOR AREA = 880.00 sf W= 17.19 & L =51.18 Side Slopes 1,2&4 = 3.1 Side Slope 3 = 4:1 Volume at 2.5' above floor =3753.9 cf Volume at 2.48' above floor =3709.8 cf Year Peak Vol WW Area 1 Area 2 Vol/Crescent 10 1.97 2666.39 880 1874.18 2651.90 INFILTRATION POND Designed as a CRESCENT FLOOR AREA = 1]14.20 sf 3:1 Side Slopes 2.5' above floor area =3008.47 sf Volume =4961.27 cf WaterWorks FLOOR AREA = 1114.20 sf W= 15.368 & L =72.50 Side Slopes 1 &3 =4:1 Side Slopes 2 &4 =3:1 Volume at 2.5' above floor =4962.8 cf Year Peak Vol WW Area 1 Area 2 Vol/Crescent '/2 0.26 307.77 1114.20 1233.69 305.09 2 0.80 1097.85 1114.20 1631.00 1091.53 10 1.40 2201.45 1114.20 2095.21 2210.75 100 2.32 4444.93 1114.20 2853.52 4447.29 it 1/12/04 12 :11 :7 am Marley Young Engineer page 1 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm ----------------------------BASIN SUMMARY BASIN ID: A NAME: 1/2 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : TYPEIA 1.01PERV IMP PRECIPITATION. . . . : 2 .24 inches AREA. • : 1.01 Acres 8 .00 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 85 . 00 98 .00 TC. . . . . 5 .00 min 5. 00 min ABSTRACTION COEFF: 0 -20 TcReach - Shallow L: 110-00 ks:27- 00 s: 0 .0400 PEAK RATE: 0 .31 cfs VOL: 0 .12 Ac-ft TIME: 480 min BASIN ID: B NAME: 2 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . 1.24 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP N PRECIPITATION. . . . : 3 .50 inches AREA. . : 1.01 Acres 0.23 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 85 .00 98 . 00 TC. . . . . 5 .00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 200 .00 ks:13 - 00 s:0 .0200 PEAK RATE: 0 . 63 cfs VOL: 0.23 Ac-ft TIME: 480 min BASIN ID: C NAME: 10 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . . . : 4.75 inches AREA. . : 1. 01 Acres 0 .23 Acres TIME INTERVAL. . . . : 5-00 min CN. . . . : 85 .00 98 .00 TC. . . . . 5 .00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 - 00 ks :27 -00 s: 0 . 0400 PEAK RATE: 0 -97 cfs VOL: 0 .35 Ac-ft TIME: 480 min l J 1/12/04 12 :11:7 am Marley Young Engineer page 2 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROD 2003-19 2003-19x.pgm ---------------------------- BASIN SUMMARY BASIN ID: D NAME: 100 yr storm EXISTING SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE- _ - - : TYPEIA 1. 01PERV IMP PRECIPITATION. . . . : 6.75 inches AREA. . : 1. 01 Acres 8 - 00 Acres TIME INTERVAL. . . . : 5 .00 min CN. . . . : 85. 00 98 . 00 TC- - - - : 5 .00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110. 00 ks:27.00 s:0. 0400 PEAK RATE: 1 .52 cfs VOL: 0 .55 Ac-ft TIME: 480 min BASIN ID: LC NAME: 10 year storm EXISTING SBUH METHODOLOGY TOTAL AREA. - - - - - - : 0.66 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION_ . . . : 4.75 inches AREA. 0.50 Acres 0 - Acres TIME INTERVAL_ . . . : 5 . 00 min CN. . . . : 85.00 98 .00 TC. . . . : 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0.20 TcReach - Shallow L: 110 - 00 ks:27 . 00 s:0. 0400 PEAK RATE: 0 .52 cfs VOL: 0 .19 Ac-ft TIME: 480 min BASIN ID: a NAME: 1/2 year storm developed SBUH METHODOLOGY TOTAL AREA- - - - - - - : 1.24 Acres BASEFLOWS: 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERV IMP PRECIPITATION. . _ . : 2 .24 inches AREA. 0 .69 Acres . Acres TIME INTERVAL_ . . . : 5 .00 min CN. . . . : 85. 00 98. 00 TC. . . . . 5. 00 min 5. 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 .00 ks:27 - 00 s : 0 .0400 PEAK RATE: 0 .39 cfs VOL: 0 .15 Ac-ft TIME: 480 min 1/12/04 12 :11 : 7 am Marley Young Engineer page 3 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROD 2003-19 2003-19x.pgm BASIN SUMMARY BASIN ID: b NAME: 2 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: PERV00 cfs IMP RAINFALL TYPE- _ - - : TYPEIA PRECIPITATION. . . . : 3 .50 inches AREA. . : 0 .69 Acres 0.55 Acres TIME INTERVAL_ . . . : 5.00 min CN. . . . : 85 . 00 98 -00 TC- - _ - : 5. 00 min 5. 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110. 00 ks:27 . 00 s:0 . 0400 PEAK RATE: 0 . 72 cfs VOL: 0.27 Ac-ft TIME: 480 min BASIN ID: c NAME: 10 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . : 1.24 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . .. TYPEIA 0.69PERV IMP PRECIPITATION. . . . : 4.75 inches AREA. - : 0.69 Acres 8 . 00 Acres TIME INTERVAL. . . . : 5. 00 min CN. . . . : 85.00 98 . 00 TC- - . - _ 5.00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 .00 ks:27 .00 s:0 .0400 PEAK RATE: 1 . 05 cfs VOL: 0 .39 AC-ft TIME: 480 min BASIN ID: d NAME: 100 year storm developed SBUH METHODOLOGY TOTAL AREA. . . . . . . . 1.24 Acres BASEFLOWS: 0 . 00 cfs I� RAINFALL TYPE. . . . - TYPEIA PERV IMP PRECIPITATION. . . . : 6.75 inches AREA. . : 0 .69 Acres 0 .55 Acres TIME INTERVAL. . . . : 5.00 min CN. . . . : 85 .00 98 .00 TC. . . . _ 5 . 00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks:27 . 00 s: 0 - 0400 PEAK RATE: 1 .60 cfs VOL: 0 .59 Ac-ft TIME: 480 min i 1/12/04 12 .11:7 am Marley Young Engineer Page 4 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 ---BASIN SUMMARY BASIN ID- dbuild NAME: 100 year storm off of building SBUH METHODOLOGY TOTAL AREA- - - - - - - : 0 .10 Acres BASEFLOWS: PERv00 cfs IMP RAINFALL TYPE. . . . : TYPEIA 0 -00 Acres 0 .10 Acres PRECIPITATION. . . . : 6 .75 inches AREA. . : 0. 00 98 . 00 TIME INTERVAL. . - - : 5.00 min CN_ - - - : 0 .00 min 5 . 00 min ABSTRACTION COEFF: 0 .20 TcReach - Shallow L: 110 . 00 ks :27 . 00 s: 0. 0400 PEAK RATE: 0 .14 cfs VOL: 0 . 05 Ac-ft TIME: 480 min l Marley Young Engineer page 5 1/12/04 12 :11:7 am CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION2 PROJ 2003-19 -- STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. ST Description: SEDIMENT POND DURING COi�'I'R9�t. Length: 51.18 ft. width: Side Slope 3 : 4 Side Slope 1: 3 Side Slope 4: 3 Side Slope 2 : 3 Inch Infiltration Rate: 7 .50 min/ sTAGB <----STORAGH----> STAGE <----STORAGE----> STAGS <----gxOftAGB----> STAGE <--cf--- A-A ---> ---cf--- --AC-Ft- (ft) (ft) ---cf--- --AC-Ft- STAGE ---cf--- --Ac-Ft- (ft) ---ef--- --Ac-Ft- (ft) __ 100.00= =0.0000 0.0000 100.65 665.99 090153-c 101.30 153E 0.0353 101.00 2726 0.0626 100.05 44.525 0.0010 100.70 725.37 0.o167 101.35 1612 O_0370 102.00 48 100.10 90.129 0.0021 100.75 785.95 0.0180 101.40 1689 0.0388 102.05 2822 0.0670 100.15 136.82 0.0031 100.60 847.77 0.0195 101.50 1848 0.040E 102.10 15 3019 0.0693 100.20 184.62 0.0042 100.85 910.82 0.0209 101.50 1929 0.0443 102.20 25 3221 0.0739 100_25 233.52 0.0054 100.90 975.11 0.0224 101.55 1929 D.0443 102.20 3119 0.071 100.30 283.55 0.0065 100.95 1041 0.0239 101.60 2012 0.0462 102.30 100.35 334.70 0.0077 101.00 1107 0.0254 101.65 2096 0.0481 102.35 3324 0.0763 100.40 387.00 0.0089 101.05 1176 0.0270 101.70 2182 0.0501 102.40 3536 0.0812 100.45 440.45 0.0101 101.10 1245 0.0286 101.75 2269 0.0521 102.45 3644 0.0837 100.50 495.07 0.0114 101.15 1316 0.0302 101.80 2358 0.0 62 lo2.s0 3754 0.0862 100.55 550.86 0.0126 101.20 1461 0.0335 101.85 100.60 607.83 0.0140 1oi.25 1461 0.0335 101.90 2539 0.0583 1 J 1/12/04 12 :11:7 am Marley Young Engineer page 6 CADY PROFESSIONAL MALL STORMWATER CONTROL 'TOTAL INFILTRATION ___-- PROD 2003-19 ---- -- - STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct ST STAGS <-1M7X1dT=1C T-> STAGB c-IIiFlr.�nza r'rO27-> STAGE <-INFILTRATION-> STAGS <-INFILTRATION-> (ft) ---cfs-- ------- (ft) ---cfa-- ----- -- (ft) ---cfs-- ------- (ft) ---cfa-- ------- 101 30== 0.2848 101.95 0.3560 100.00 0.1629 100.65 0.2204 100.05 0.1671 100.70 0_2251 101.35 0.2900 102_DD O_3618 100.10 0.1713 100.75 0.2299 101.40 0_2953 102-OS 0.3676 100.15 0.1756 100.80 0.2346 101.45 0.3006 102- 10 D.3734 5 101.50 0.3060 102-15 0.3793 100.20 0.1799 100.85 0.239 102.20 0.3852 100.25 0.1842 100.90 0.2443 101.55 0.3114 100.30 0.1886 100.95 0.2493 201.60 0.3166 102-25 0.3912 100.35 0.1930 101.00 0.2542 101.65 0.3223 102-30 O_3972 100.40 0.1975 101.05 0.2592 101.70 0.3278 102.35 0.4033 100.45 0.2020 101.10 0_2642 101.75 0.3334 102-40 0.4094 100.50 0.2065 101.15 0.2693 101.80 0.3390 102.45 O.4155 100.55 0.2112 101.20 0.2744 101.85 0.3446 102.50 D.4217 100.60 0.2157 101.25 0.2796 101.90 0.3503 III L -J 1/12/04 12 :11:7 am Marley Young Engineer page 7 CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PN PROJ 2003-19 -------------------------- gm ST-A-G-E------- STORAGE TABLE TRAPEZOIDAL BASIN ID No. Tb Description: Length: 72 .50 ft. width: 15.37 ft. Side Slope 1: 4 Side Slope 3 : 4 Side Slope 2 : 3 Side Slope 4: 3 Infiltration Rate: 7 .50 min/inch STAGS <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGS <----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-F't- (ft) ---cf--- --Ac-Ft- (ft) cf--- Ae-Ft- 100 00 0,0000 0.0000 100.65 858.64 0.0197 101.30 2004 0.0460 101.95 3463 0.0795 100.05 56.480 0.0013 100.70 936.22 0.0215 101.35 2105 0.0483 102.00 3589 0.0924 100.10 114.51 0.0026 100.75 1016 0.0233 101.40 2207 0.0507 102.05 3717 0.0853 100.15 174.10 0.0040 100.60 1097 0.0252 101.45 2312 0.0531 102.10 3847 0.0883 100.20 235.27 0.0054 100.85 1179 0.0271 101.50 2418 0.0555 102.15 3979 0.0914 100.25 298.02 0.0068 100.90 1264 0.0290 101.55 2527 0.0580 102.20 4114 0.0944 100.30 362.37 0.0083 100.95 1350 0.0310 101.60 2637 0.0605 102.25 4250 0.0976 100.35 428.34 0.0098 101.00 1438 0.0330 101.65 2749 0.0631 102.30 4388 0.1007 100.40 495.92 0.0114 101.05 1528 0.0351 101.70 2863 0.0657 102.35 4529 0.1040 100.45 565.15 0.0130 101.10 1619 0.0372 101.75 2979 0.0684 102.40 4671 0.1072 100.50 636.02 0.0146 101.15 1713 0.0393 101.80 3097 0.0711 102.45 4816 0.1106 100.55 708.55 0.0163 101.20 1808 0.0415 101.85 3217 0.0739 102.50 4963 0.1139 100.60 782.75 0.0180 101.25 1905 0.0437 101.90 3339 0.0767 Marley Young Engineer page 8 1/12/04 12 :11:7 am Y CADY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROD 2003-19 2003-19x.pgm STAGE STORAGE TABLE Infiltration Rating Curve for Storage Struct Tb STAGE <-IU71LTRATI0N-> STAGE <-nWILTRATION-> STAGE c-INFILTRATION-> STAGE <-INnLTRATION-> (ft) ---cfe-- ------- (ft) ---cfa-- ------- (ft) ---cfa-- ------- (ft) ---cfa-- ------- 101.30�--0.3764 101-95 0.4734 100.00 0.2063 100.65 0.2874 100.05 0.2123 100.70 0.2939 101_35 0.3836 102_00 0_4812 100.10 0.2183 100.75 0.3006 101.40 0.3908 102.05 0.4890 100.15 0.2243 100.80 0.3072 101.45 0.3981 102.10 0-4969 100.20 0.2304 100.85 0.3139 101-50 0.4054 102.15 0_5049 100.25 0.2366 100.90 0.3207 101.55 0.4128 102.20 0.5128 100.30 0.2427 100.95 0.3275 101.60 0.4202 102.25 0.5209 100.35 0.2490 101.00 0.3343 101.65 0.4276 102.30 0_5289 100.40 0.2553 101.05 0.3412 101.70 0.4352 102.35 0.5371 100.95 0,2616 101.10 0.3482 101.75 0.4427 102.40 O.5452 100.50 O.2680 101.15 0.3551 101.80 0.4503 102.45 0.5535 100.55 0.2744 101.20 0.3622 101.85 0.4580 102.50 0.5617 100.60 0.2809 101.25 0.3693 101.90 0.4657 1/12/04 12 .11:7 am Marley Young Engineer page 9 CA.DY PROFESSIONAL MALL STORMWATER CONTROL TOTAL INFILTRATION PROJ 2003-19 2003-19x.pgm -------------------------- -------- ---------------------- STAGE DISCHARGE TABLE OVERFLOW WEIR ID No. W Description: Ratio (h:1v) : 3 .2100 Weir length: 4.0000 ft. El: 103 .00 ft. Weir Increm: 0.05 STAW <--DIScHAR=---> STAW <--DISCMR=---> STEM <--DISCMW=---> STD <--DISCFUUW B---> (ft) cfs-- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---c£s-- ------- 103-00� 0.0000 103.30 2.5267 103.60 8.2960 103.90 17.352 103.05 0_1489 103.35 3.2694 103.65 9.5703 103.95 19_200 103.10 0_4341 103.40 4_0997 103.70 10_937 104.00 21.147 103.15 0.9215 103.45 5.0151 103.75 12.397 103.20 1.3016 103.50 6.0195 103.80 13.952 103.25 1.8706 103.55 7.1128 103.85 15.603 1/12/04 12:11.7 am Marley Young Engineer page 10 CADY PROFESSIONAL MALL STORMWgTER CONTROL TOTAL INFILTRATION -----______ PROD 2003-19 2003=19x_p9 _________________________ HISTORY OF HYDROGRAPH ACTIVITY Dots of Session: 1/12/04 12:10:11 am CLMOUS MOVE A to 1 0.3126 cfa 0.1209 ac-ft 8.00 bra MOVE B to 2 8.00 hra 0.6326 cfs 0.2327 ac-ft MOVE C to 3 8.00 brs 0-9693 cfs 0.3511 ac-ft HOVE D to 4 8.0o hre 1.5186 cfa 0.5474 ae-ft MOVE a to 5 8.00 bra 0.3937 cf8 0.1486 aC-ft MDVE b to 6 0.7191 cfs 0.2660 ac-ft 8.00 bra MOVE c to 7 8.00 bra 1.0543 cfs 0.3878 ac-ft MDVE d to 8 g.00 hra 1.5971 cf8 0.5874 aC-ft IpWL 1 -1/2- 1 5 Tb W 9 PkStg100.26 OutQ byd Volume 0.24 9 MatchQ PeakQ Sto Die Deacriptipa 307.77 of 1/2 0.31 0.39 Tb W Lp00L 2 -2- 2 6 7b W 10 b Pe PkStg OutQ byd Volume Matc4 Pew Sto Diu Descriptionp-63 0.72 Tb W 100.80 0.31 10 1097.95 of 2 LpWL 3 -10- 3 7 Tb W 11 PkStg OutQ byd Volume MatcbQ peakQ Sto Die Description 2201.45 of 0.97 1.05 Tb W 101_40 0.39 11 10 LVOOL 4 -100- 4 8 Tb W 12 c PkStg OutQ bYd Volume MatcbQ PeakQ Sto Dig Description 3-2 4444.93 of 1-52 1.60 14a W 102.32 0.53 100 SPLIT W 1 13 17 0.0000 cfe 0.0000 ac-ft O.00 bra 0.2375 cfs 0.1486 ac-ft 8.25 bra SPLIT W 2 14 18 L j MARLEY L. YOUNG, CONSULTING ENGINEER P.O. BOX 1343, SHELTON, WA 98584-0959 �:;Ci vi I Engineering i (360)426-7475-(360)490-0939-Fax(360)426-5789 Stormwater Site Plans I I Marley L. Young, P.E., P.L.S. Sewer Extensions Civil Engineer& Land Surveyor 0 ,lillli8l CADY ET AL Reed Realty Building- Belfair 2/9/04 Quattro Pro EMERGENCY OVERFLOW WEIR 2003-19.wb1 CALCULATION OF THE WATER DEPTH OVER THE OVERFLOW WEIR tab A DOE Manual Fig III-4.3 Q 1 00=3.21(LH^3/2+2.41-1^5/2) Trial Method If Q100= 1.6 If L= 6 and H= 0.182 <0.2 O.K. 0.465863 0.033915 then Q100= 1.604287 Q100 ACTURAL 1.6 O.K. Calculate Velocity V=Q/A Doe Manual pg 1-6-21 AREA= LH + 3*H^2 L= 6 H= 0.182 AREA = 1.191372 then V= 1.346588 fps< 1.5fps O.K. DISCHARGE OF EMERGENCY OVERFLOW SPILLWAY DOES NOT REACH EROSION VELOCITY 14144 e; h L �