JW301 Final Drainage Report v2
Wentworth Commercial Site
Final Stormwater Control Plan
Date Prepared 12/22/22
Subject Property 313 Yelm Ave W
Yelm WA, 98597
TP #: 75300900100
Applicant Jennifer Wentworth
wentworthje@gmail.com
Reviewing Agency City of Yelm
Community Development
106 2nd St SE
Yelm, WA 98597
Project Engineer Nicholas D. Taylor, PE
The Iris Group PLLC
(360) 890-8955
ntaylor@irisgroupconsulting.com
"I hereby certify that this Stormwater Control Plan has been prepared by me or under my supervision and meets
minimum standards of The City of Yelm and normal standards of engineering practice. I hereby acknowledge and
agree that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of
drainage facilities designed by me."
12/22/22
Stormwater Control Plan 2 of 6
Wentworth Commercial Site
Table of Contents
Section 1 – Proposed Project Description ..................................................................................................................... 3
Minimum Requirements ............................................................................................................................................ 3
MR #1 – Preparation of Drainage Control Plans .................................................................................................... 3
MR #2 – Construction Stormwater Pollution Prevention (SWPP) ......................................................................... 3
MR #3 – Source Control of Pollution ..................................................................................................................... 3
MR #4 – Preservation of Natural Drainage Systems and Outfalls ......................................................................... 3
MR #5 – Onsite Stormwater Management ............................................................................................................ 3
MR #6 – Runoff Treatment .................................................................................................................................... 3
MR #7 – Flow Control ............................................................................................................................................ 3
MR #8 – Wetlands Protection ................................................................................................................................ 4
MR #9 – Operation and Maintenance ................................................................................................................... 4
Section 2 – Existing Conditions ...................................................................................................................................... 4
Section 3 – Soils Investigation ....................................................................................................................................... 4
Section 4 – Wells and Septic Systems ............................................................................................................................ 4
Section 5 – Fuel Tanks ................................................................................................................................................... 4
Section 6 – Subbasin Description .................................................................................................................................. 4
Section 7 – Floodplain Analysis ...................................................................................................................................... 4
Section 8 – Aesthetic Considerations for Facilities ........................................................................................................ 4
Section 9 – Facility Selection and Sizing ........................................................................................................................ 5
Section 10 – Conveyance System Analysis .................................................................................................................... 5
Section 11 – Offsite Analysis & Mitigation .................................................................................................................... 5
Section 12 – Utilities ...................................................................................................................................................... 5
Section 13 – Covenants, Dedications, Easements, Agreements .................................................................................... 6
Section 14 – Other Permits or Conditions Placed on the Project .................................................................................. 6
Appendices A. SMMWW Figures
B. Site Improvement Plans
C. WWHM Modeling Report
D. Soils Report
E. Bay Filter Design Specifications
F. Construction Stormwater Pollution Prevention Plan (SWPPP)
G. Facility Maintenance Requirements
Stormwater Control Plan 3 of 6
Wentworth Commercial Site
Section 1 – Proposed Project Description
This Stormwater Control Plan (SCP) is associated with a civil permit application for approval to construct
improvements on a 0.28-acre commercial site with service-oriented use within the City of Yelm. City zoning of the
project site is Central Business District (CBD) in which the proposed use is a permitted use.
This project proposes to add additional parking to the existing site and on Rice St. All onsite sidewalk, driveway, and
lawn runoff will sheet flow to a proposed catch basin near the western corner of the proposed parking lot where it
will be captured and conveyed to a proposed single-cartridge Bayfilter catch basin for treatment before being
discharged to a proposed infiltration gallery. Roof runoff from the existing buildings will be captured and conveyed
directly to the proposed infiltration gallery. Runoff from Rice St will be collected in proposed curb/gutter and catch
basins then conveyed to the onsite Bayfilter catch basin for treatment before being discharged to the proposed
onsite infiltration gallery.
This SCP was prepared in accordance with the 2019 Stormwater Management Manual for Western Washington
(SMMWW). Discussion of how the project will meet all applicable Minimum Requirements is provided below.
Minimum Requirements
Per SMMWW Volume 1, figure I-3.1, of which an annotated version is provided as Appendix A to this report,
Minimum Requirements 1-5 apply to the new and replaced hard surfaces, as well as converted vegetation areas.
MR #1 – Preparation of Drainage Control Plans
Preparation of this SCP meets the intent of Minimum Requirement #1.
MR #2 – Construction Stormwater Pollution Prevention (SWPP)
A Construction SWPPP is included as Appendix E to this report.
As there is currently no anticipated discharge from the site, it is anticipated that the project will not be required to
obtain coverage under the Washington State Construction Stormwater General Permit.
MR #3 – Source Control of Pollution
A Pollution Source Control Program (PSCP) is not required.
MR #4 – Preservation of Natural Drainage Systems and Outfalls
In the existing condition there is no outfall at which concentrated flow enters or leaves the site. There is little to no
offsite run-on to the development area.
MR #5 – Onsite Stormwater Management
Per SMMWW Volume 1, figure I-3.3, of which an annotated version is provided as Appendix A to this report, this
project has chosen to meet the LID Performance standard through use of an infiltration gallery.
MR #6 – Runoff Treatment
Runoff treatment will be provided by a Bayfilter catch basin, sized per Section 9 below. The proposed filter unit has
Ecology general use approval for basic treatment at 0.060 cfs flow rate for the single-cartridge 522 unit.
MR #7 – Flow Control
Flow control is categorically not required, as the project proposes less than 10,000 SF of new hard surface, it
proposes to convert less then ¾ of an acre from forested to lawn, and the increase in the 100 year flow rate is
negative, as all runoff will be infiltrated on the site.
Stormwater Control Plan 4 of 6
Wentworth Commercial Site
MR #8 – Wetlands Protection
As this project does not discharge into a wetland, Minimum Requirement #8 is not applicable to this project.
MR #9 – Operation and Maintenance
Maintenance of the infiltration system shall be performed in accordance with SWMM Table V-A.1, V-A.2, and V-A.5,
included in Attachment G (Facility Maintenance Requirements).
Basins
The entire limits of disturbance is modeled as a single basin.
Section 2 – Existing Conditions
The site is generally rectangular in shape, with all onsite surfaces sloping down toward the western corner of the
site. Two building structures exist on the site, with paved parking space for 1 or 2 vehicles. The total topographic
relief across the site is on the order of 2’ feet and is depicted on the Site Improvement Plans included as Appendix
B).
Vegetation across the site generally consists of deciduous and coniferous trees and lawn. No areas of surficial
erosion, standing water, seeps, springs, or deep-seated slope movement were observed during site reconnaissance
or questioning of the owner.
Section 3 – Soils Investigation
The USDA Natural Resource Conservation Service (NRCS) Web Soil Survey maps the site as being underlain by
Spanaway gravelly sandy loam, 0 to 3 percent slopes (hydrologic soils group A).
The project Geotechnical Engineer has indicated that a design infiltration rate of 6.0 in/hr should be used for
designing the proposed infiltration facility. A soils report is included as Appendix D to this report.
Section 4 – Wells and Septic Systems
There are no known wells or septic systems onsite.
Section 5 – Fuel Tanks
There is no indication of existing above or below grade fuel tanks on the property.
Section 6 – Subbasin Description
There is no significant off-site drainage tributary to the project.
Section 7 – Floodplain Analysis
FEMA does not list the site as being within a flood zone.
Section 8 – Aesthetic Considerations for Facilities
The proposed facilities will be below grade and not visible.
Stormwater Control Plan 5 of 6
Wentworth Commercial Site
Section 9 – Facility Selection and Sizing
The proposed Bayfilter catch basin is sized to meet the Western Washington Hydrology Model (WWHM) online
treatment flow rate. The proposed filter unit has Ecology general use approval for basic treatment at 0.060 cfs flow
rate for the single-cartridge unit. Per WWHM, the required online treatment flow rate is 0.0390 cfs. See Appendix
E for Bayfilter design specifications.
The proposed infiltration gallery will consist of Stormtech SC740 chambers and was sized using WWHM and a 6.0
in/hr infiltration rate for the basin areas listed in Table 1 below. The gallery was modeled as a gravel trench bed
with 4’ total depth and a gravel void ratio of 40%, with 65% total voids where chambers are installed. For the
proposed 15.75’ x 50.23’ infiltration facility, the required detention volume is 0.040 ac-ft, and the proposed
detention volume is 0.0404 ac-ft. 100% of the inflow hydrograph is infiltrated, categorically meeting the LID
performance standard.
Basins
Tabulation of basin areas is included in Table 1 below. There is one proposed basin.
Area (SF)
Disturbed Area 15,459
Existing Hard Surface 8,539
New Plus Replaced Hard Surface 5,505
Hard Surface After Project 9,721
Lawn and Landscape After Project 5,738
New + Replaced Pollution Generating Hard Surface 8,233
Proposed Effective Hard Surface 0
Table 1 – Surface Coverage
Basin coverage types and areas used for WWHM modeling are included in Table 2 below.
Area (SF)
A/B Lawn/Landscaping (PGPS) 5,738
Roads/Driveways (PGPS) 9,721
Roof (NPGS) 1,488
Table 2 – Modeling Basins
Section 10 – Conveyance System Analysis
Subgrade conveyance for the emergency overflow drainage system will consist of SDR35 PVC pipe sized to convey
the 100-year event flow.
Section 11 – Offsite Analysis & Mitigation
This section is not applicable as stormwater will not be discharged to an offsite conveyance.
Section 12 – Utilities
All proposed utilities will be installed in accordance with applicable code and required separation shall be provided.
There are no anticipated utility conflicts with the proposed stormwater system.
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Wentworth Commercial Site
Section 13 – Covenants, Dedications, Easements, Agreements
There are no proposed onsite facilities that would require covenants, dedications, easements, or agreements.
Section 14 – Other Permits or Conditions Placed on the Project
Civil permits will be required for the project. There are currently no known conditions of approval.
Appendix A
Appendix B
FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
COVER SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
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2-2022 VICINITY MAPNTSSITE DATAPARCEL #:75300900100SITE ADDRESS: 313 YELM AVE WYELM, WA 98597GROSS ACREAGE: 0.28 AC (PER COUNTY DATA)ZONING:CBDPROPOSED USE: SERVICE ORIENTEDPRESIDING JURISDICTION:YELM, WASITE1.IT IS THE CONTRACTOR’S RESPONSIBILITY TO COMPLETE ALL WORKAND TO DISPOSE OF ALL DEMOLITION DEBRIS IN ACCORDANCE WITH ALLFEDERAL, STATE, AND LOCAL REGULATIONS. PRIOR TO ANY WORKCONTRACTOR SHALL COMPLETE ALL TESTING FOR HAZARDOUSMATERIALS AND SHALL ABATE ALL HAZARDOUS MATERIALS INACCORDANCE WITH ALL FEDERAL, STATE, AND LOCAL REGULATIONS.2. CONTRACTOR SHALL OBTAIN AND FULFILL THE REQUIREMENTS OF ANYPERMITS REQUIRED FOR ANY PROPOSED DEMOLITION ACTIVITY.3. CONTRACTOR SHALL COORDINATE WITH AND RECEIVE APPROVAL FROMANY PUBLIC OR PRIVATE UTILITIES AS REQUIRED FOR ABANDONMENTOF UTILITY SERVICES. CONTRACTOR SHALL APPLY FOR ANDCOORDINATE ANY WORK THAT MUST BE COMPLETED BY THE UTILITYPURVEYOR. CONTRACTOR SHALL ENSURE THAT ALL UTILITIES TO BEMODIFIED OR REMOVED ARE SHUT OFF PRIOR TO DEMOLITION ORCONSTRUCTION ACTIVITY.4. PRIOR TO ANY DEMOLITION OR REMOVAL/MODIFICATION OF EXISTINGUNDERGROUND UTILITY SERVICES, CONTRACTOR SHALL PERFORMBOTH A PRIVATE AND PUBLIC UTILITY LOCATE TO IDENTIFY THEHORIZONTAL AND VERTICAL LOCATIONS OF ALL EXISTINGUNDERGROUND UTILITIES.5. CONTRACTOR IS RESPONSIBLE FOR PROTECTION AND PRESERVATIONOF ANY EXISTING FEATURES TO REMAIN.6. CONTRACTOR IS RESPONSIBLE FOR DEMOLITION AND DISPOSAL OF ALLEXISTING FEATURES THAT CONFLICT WITH PROPOSED FEATURES.7. APPROVAL OF THIS SWPPP DOES NOT CONSTITUTE AN APPROVAL OFPERMANENT ROAD OR DRAINAGE DESIGN (E.G., SIZE AND LOCATION OFROADS, PIPES, RESTRICTORS, CHANNELS, RETENTION FACILITIES,UTILITIES, ETC.)8. THE IMPLEMENTATION OF THIS SWPPP AND THE CONSTRUCTION,MAINTENANCE, REPLACEMENT, AND UPGRADING OF THESE ESCFACILITIES IS THE RESPONSIBILITY OF THE APPLICANT/CONTRACTORUNTIL ALL CONSTRUCTION IS COMPLETED AND APPROVED ANDVEGETATION/LANDSCAPING IS ESTABLISHED.9. DURING THE CONSTRUCTION PERIOD, NO UNAUTHORIZED DISTURBANCEBEYOND THE PROPERTY BOUNDARY SHALL BE PERMITTED.10.THE ESC FACILITIES SHOWN ON THIS PLAN MUST BE CONSTRUCTED INCONJUNCTION WITH ALL CLEARING AND GRADING ACTIVITIES, AND INSUCH A MANNER AS TO INSURE THAT SEDIMENT AND SEDIMENT LADENWATER DO NOT ENTER THE DRAINAGE SYSTEM, ROADWAYS, ORVIOLATE APPLICABLE WATER STANDARDS.11.THE ESC FACILITIES SHOWN ON THIS PLAN ARE THE MINIMUMREQUIREMENTS FOR ANTICIPATED SITE CONDITIONS. DURING THECONSTRUCTION PERIOD, THESE ESC FACILITIES SHALL BE UPGRADEDAS NEEDED FOR UNEXPECTED STORM EVENTS AND TO ENSURE THATSEDIMENT AND SEDIMENT-LADEN WATER DO NOT LEAVE THE SITE.12.THE ESC FACILITIES SHALL BE INSPECTED DAILY BY THEAPPLICANT/CONTRACTOR AND MAINTAINED AS NECESSARY TO ENSURETHEIR CONTINUED FUNCTIONING.13.THE ESC FACILITIES ON INACTIVE SITES SHALL BE INSPECTED ANDMAINTAINED A MINIMUM OF ONCE A MONTH OR WITHIN THE 48 HOURSFOLLOWING A MAJOR STORM EVENT.14.AT NO TIME SHALL MORE THAN 1 FOOT OF SEDIMENT BE ALLOWED TOACCUMULATE WITHIN A TRAPPED CATCH BASIN. ALL CATCH BASINS ANDCONVEYANCE LINES SHALL BE CLEANED PRIOR TO PAVING. THECLEANING OPERATION SHALL NOT FLUSH SEDIMENT LADEN WATER INTOTHE DOWNSTREAM SYSTEM.15.STABILIZED CONSTRUCTION ENTRANCES SHALL BE INSTALLED AT THEBEGINNING OF CONSTRUCTION AND MAINTAINED FOR THE DURATION OFTHE PROJECT. ADDITIONAL MEASURES MAY BE REQUIRED TO ENSURETHAT ALL PAVED AREAS ARE KEPT CLEAN FOR THE DURATION OF THEPROJECT.1. THE CONTRACTOR SHALL BE FULLY RESPONSIBLE FOR BEINGFAMILIAR WITH THE PROVISIONS AND REQUIREMENTS CONTAINEDIN JURISDICTIONAL STANDARD SPECIFICATIONS. THE CONTRACTORSHALL HAVE A COPY AVAILABLE AT THE JOB SITE AT ALL TIMES.2. THE CONTRACTOR SHALL NOTIFY THE PUBLIC WORKSDEPARTMENT AT LEAST 48 HOURS PRIOR TO COMMENCEMENT OFWORK.3. THE CONTRACTOR SHALL NOTIFY ALL PUBLIC OR PRIVATE UTILITYCOMPANIES 48 HOURS PRIOR TO COMMENCEMENT OF WORKADJACENT TO EXISTING UTILITY LINES UNLESS AN ENCROACHMENTPERMIT SPECIFIES OTHERWISE.4. THE CONTRACTOR SHALL PROVIDE EMERGENCY TELEPHONENUMBERS TO THE POLICE, FIRE, AND PUBLIC WORKSDEPARTMENTS AND KEEP THEM INFORMED DAILY REGARDINGSTREETS UNDER CONSTRUCTION AND DETOURS. DETOURS SHALLNOT BE PERMITTED UNLESS APPROVED IN WRITING BY THE PUBLICWORKS DIRECTOR.5. THE CONTRACTOR SHALL PROVIDE AND MAINTAIN SUFFICIENTBARRICADES TO PROVIDE FOR THE SAFETY OF THE GENERALPUBLIC TO THE SATISFACTION OF THE PUBLIC WORKS DIRECTOR.6. ALL MATERIALS SHALL BE FURNISHED AND INSTALLED BY THECONTRACTOR UNLESS OTHERWISE NOTED.7. THE CONTRACTOR SHALL CONFORM TO EXISTING STREETS,SURROUNDING LANDSCAPE AND OTHER IMPROVEMENTS WITH ASMOOTH TRANSITION IN PAVING, CURBS, GUTTERS, SIDEWALKS,GRADING, ETC., AND AVOID ANY ABRUPT OR APPARENT CHANGESIN GRADES OR CROSS SLOPES, LOW SPOTS OR HAZARDOUSCONDITIONS.8. THE CONTRACTOR SHALL COORDINATE ALL NECESSARY UTILITYRELOCATIONS, IF REQUIRED, WITH THE APPROPRIATE UTILITYCOMPANIES.9. THE CONTRACTOR SHALL CONDUCT ALL GRADING OPERATIONS INSUCH A MANNER AS TO PRECLUDE WIND BLOWN DIRT AND DUSTAND RELATED DAMAGE TO NEIGHBORING PROPERTIES. SUFFICIENTWATERING TO CONTROL DUST IS REQUIRED AT ALL TIMES. THECONTRACTOR SHALL ASSUME ALL LIABILITY FOR CLAIMS RELATEDTO WIND BLOWN MATERIAL. IF THE DUST CONTROL IS INADEQUATEAS DETERMINED BY THE PUBLIC WORKS DIRECTOR OR HISDESIGNATED REPRESENTATIVE, THE CONSTRUCTION WORK SHALLBE TERMINATED UNTIL SUCH CORRECTIVE MEASURES ARE TAKEN.10.THE CONTRACTOR SHALL NOTIFY THE APPROPRIATE AGENCIESAND DEPARTMENTS FOR ALL REQUIRED INSPECTIONS PRIOR TOPLACING ANY UTILITIES INTO SERVICE.11.THE DESIGN SHOWN IS BASED UPON THE ENGINEER'SUNDERSTANDING OF THE EXISTING CONDITIONS. THIS PLAN DOESNOT REPRESENT A DETAILED FIELD SURVEY.12.CAUTION - NOTICE TO CONTRACTOR THE CONTRACTOR ISSPECIFICALLY CAUTIONED THAT THE LOCATION OF EXISTINGUTILITIES AS SHOWN ON THESE PLANS IS BASED ON RECORDS OFTHE VARIOUS UTILITY COMPANIES AND, WHERE POSSIBLE,MEASUREMENTS TAKEN IN THE FIELD. THE INFORMATION IS NOT TOBE RELIED ON AS BEING EXACT OR COMPLETE, THE CONTRACTORMUST CALL THE APPROPRIATE UTILITY COMPANY AT LEAST 48HOURS BEFORE ANY EXCAVATION TO REQUEST EXACT FIELDLOCATION OF UTILITIES. IT SHALL BE THE RESPONSIBILITY OF THECONTRACTOR TO RELOCATE ALL EXISTING UTILITIES WHICHCONFLICT WITH THE PROPOSED IMPROVEMENTS SHOWN ONTHESE PLANS.13.ALL DETAILS PROVIDED IN THESE PLANS SHALL BE APPLIED TO ALLAPPLICABLE PROPOSED CONSTRUCTION, REGARDLESS OFWHETHER OR NOT SPECIFIC REFERENCES TO APPLICABLE DETAILSARE MADE.14.POST CONSTRUCTION SOIL QUALITY AND DEPTH BMP DETAIL 3/C1SHALL BE APPLIED TO ALL DISTURBED PERVIOUS AREAS.15.DO NOT COMPACT THE BOTTOM OF THE INFILTRATION GALLERYDURING EXCAVATIONEROSION CONTROL NOTESTHE WORK ON THIS PROJECT SHALL BE PERFORMED IN ACCORDANCE WITHTHE CITY OF YELM STANDARDS, AND THE STANDARD SPECIFICATIONS FORROAD, BRIDGE AND MUNICIPAL CONSTRUCTION, 2022 WASHINGTON STATEDEPARTMENT OF TRANSPORTATION (WSDOT) (HEREAFTER "STANDARDSPECIFICATIONS")ALSO INCORPORATED INTO THESE CONTRACT DOCUMENTS BYREFERENCE ARE:A. CITY OF YELM DEVELOPMENT GUIDELINES, CURRENT EDITIONB. WASHINGTON STATE DEPARTMENT OF ECOLOGY STORMWATER MANAGEMENT MANUAL FOR WESTERN WASHINGTON, 2019 EDITION ("DRAINAGE MANUAL")C. THE INTERNATIONAL BUILDING CODE (IBC) AND THE INTERNATIONAL RESIDENTIAL CODE (IRC), CURRENT EDITIONS, WITH CITY AMENDMENTSD. MANUAL ON UNIFORM TRAFFIC CONTROL DEVICES FOR STREETS AND HIGHWAYS (MUTCD), CURRENT EDITION, WITH WSDOT MODIFICATIONSE. THE INTERNATIONAL FIRE CODE, CURRENT EDITIONF. UNIFORM PLUMBING CODE (UPC), 2012 EDITION, WITH CITY AMENDMENTS.G. NATIONAL ELECTRICAL CODE (NEC), CURRENT EDITION.CURRENT EDITlONS OF THESE STANDARDS SHALL BE USED WHICH EXIST ONTHE DATE OF CONTRACT ACCEPTANCE.CONTRACTOR SHALL OBTAIN COPIES OF THESE PUBLICATIONS.THE CONTRACTOR IS RESPONSIBLE FOR PROVIDING ALL LABOR,MATERIALS, TOOLS, EQUIPMENT, TRANSPORTATION, SUPPLIES, ANDINCIDENTALS REQUIRED TO COMPLETE ALL WORK SHOWN ON THESEDRAWINGS AND TO OBTAIN ACCEPTANCE BY THE CITY AND THE PROJECTOWNER.THE INTENT OF THESE DRAWINGS IS TO PRESCRIBE A COMPLETE WORK.OMISSIONS FROM THE DRAWINGS OF DETAILS OF WORK WHICH ARENECESSARY TO CARRY OUT THE INTENT OF THE DRAWINGS SHALL NOTRELIEVE THE CONTRACTOR FROM PERFORMING THE OMITTED WORK.ANY PROPOSED ALTERATIONS BY THE CONTRACTOR AFFECTING THEREQUIREMENTS AND INFORMATION IN THESE DRAWINGS SHALL BE INWRITING AND WILL REQUIRE APPROVAL OF THE ENGINEER AND INSPECTOR.PROJECT SPECIFICATIONSCONTRACTOR SHALL OBTAIN A RIGHT OF WAY PERMIT PRIOR TOCOMMENCING ANY WORK LOCATED IN THE CITY'S RIGHTOF WAY. ALL WORK PERFORMED IN THE CITY'S RIGHT OF WAYSHALL ADHERE TO DRAWINGS, STANDARD SPECIFICATIONS, ANDREQUIREMENTS OUTLINED IN THE RIGHT OF WAY PERMIT.WORK IN CITY RIGHT OF WAYTHE IRIS GROUP IS REQUIRED BY THE CITY TO PROVIDE RECORDDRAWING CERTIFICATION PRIOR TO FINAL CITY ACCEPTANCE. THE IRISGROUP WILL NOT CERTIFY RECORD DRAWINGS WITHOUT INSPECTIONOF BELOW GRADE UTILITIES AND STRUCTURES. PRIOR TOBACKFILLING, CONTRACTOR SHALL NOTIFY THE IRIS GROUP OFNECESSARY INSPECTIONS. THE CONTRACTOR SHALL MAINTAIN ONESET OF APPROVED PLANS ONSITE AND SHALL MARK, IN RED, ANYCHANGES TO THE PLANS THAT OCCUR DURING CONSTRUCTION.RECORD DRAWINGSIF UNSUITABLE MATERIALS AS DEFINED BY THE STANDARDSPECIFICATIONS ARE ENCOUNTERED, THIS MATERIAL SHALL BEREMOVED TO THE DEPTH REQUIRED BY THE ENGINEER OR INSPECTORAND REPLACED WITH SUITABLE MATERIALS.UNSUITABLE MATERIAL SHALL BE REMOVED FROM THE SITE ANDHAULED TO A WASTE SITE OBTAINED BY THE CONTRACTOR. PRIOR TOREMOVAL, CONTRACTOR SHALL NOTIFY PROJECT OWNER.REMOVAL OF UNSUITABLE MATERIALSSEE GEOTECHNICAL STUDY PREPARED BY MUD BAY GEOTECHNICALSERVICES, DATED 12/18/2022.GEOTECHNICAL INFORMATIONNAD 1983(2011) SOUTH ZONE; PER RTK GPS TIES AND THE WASHINGTONSTATE REFERENCE NETWORK (WSRN). UNITS OF MEASUREMENT AREU.S. SURVEY FEET.HORIZONTAL DATUMTOPOGRAPHIC INFORMATION DEPICTED IN THESE DRAWINGS WASPROVIDED IN A SURVEY BY INFORMED LAND SURVEY, DATED10/25/22. ALL EXISTING FEATURES AND TOPOGRAPHY SHOWNSHALL BE VERIFIED PRIOR TO BEGINNING CONSTRUCTION. ANY ANDALL DISCREPANCIES FOUND BETWEEN ACTUAL EXISTINGCONDITIONS AND THE EXISTING CONDITIONS SHOWN HERE SHALLBE IDENTIFIED TO THE PROJECT ENGINEER PRIOR TO CONTINUANCEOF ANY WORK.TOPOGRAPHIC DATACONSTRUCTION NOTES1 - C1 COVER2 - C2 SITE AND HORIZONTAL CONTROL PLAN3 - C3 DEMOLITION AND TESC PLAN4 - C4 STORMWATER AND UTILITY PLAN5 - C5 GRADING PLAN6 - C6 DETAILS 17 - C7 DETAILS 28 - C8 DETAILS 3SHEET INDEXWENTWORTH COMMERCIALDEVELOPMENTYELM, WA1. THE CONTRACTOR SHALL OBTAIN ALL APPROVALS AND PERMITSREQUIRED BY THE CITY OF YELM (CITY) PRIOR TO THE START OFCONSTRUCTION. A GRADING PERMIT FOR STORM PONDCONSTRUCTION MAY BE REQUIRED.2. STORM DRAIN PIPE SHALL BE ON THE WSDOT QUALIFIEDPRODUCTS LIST FOR THE SPECIFICATION LISTED BELOW:A. PLAIN CONCRETE STORM SEWER PIPE OR REINFORCEDCONCRETE STORM SEWER PIPE PER WSDOT STANDARDSPECIFICATION 9-05.7.B. SOLID WALL PVC STORM SEWER PIPE PER WSDOT STANDARDSPECIFICATION 9- 05.12(1).C. DUCTILE IRON SEWER PIPE PER WSDOT STANDARDSPECIFICATION 9-05.13.D. HANCOR BLUE SEAL ™ AND ADVANCED DRAINAGE SYSTEMS(ADS/HANCOR) N-12 HDPE AND (ADS/HANCOR) SANITITE UP TO36" IN DIAMETER PER WSDOT STANDARD SPECIFICATIONS9-05.20 AND 9-05.24.E. CONTECH DUROMAXX STEEL RIB REINFORCED POLYETHYLENEPIPE, IN DIAMETERS FROM 24 INCH TO 60 INCH PER WSDOTSTANDARD SPECIFICATION 9-05.22.3. ALL STORM DRAINAGE SYSTEMS SHALL BE AIR TESTED AT 4 PSIEXCEPT CONCRETE PIPE, WHICH SHALL BE TESTED PERWSDOT/APWA STANDARD FOR CONCRETE STORM PIPE. ALLFLEXIBLE PIPE SHALL BE MANDREL TESTED PER WSDOT/APWASTANDARDS. TESTING SHALL BE DONE BY THE CONTRACTOR.4. TESTING OF THE STORM SEWER SHALL INCLUDE VIDEOTAPING OFTHE MAIN BY THE CONTRACTOR. IMMEDIATELY PRIOR TOVIDEOTAPING, ENOUGH WATER SHALL BE RUN DOWN THE LINESO IT COMES OUT THE LOWER CATCH BASIN. A COPY OF THEVIDEO TAPE SHALL BE SUBMITTED TO THE CITY. ACCEPTANCE OFTHE LINE WILL NOT BE MADE UNTIL AFTER THE TAPE HAS BEENREVIEWED AND APPROVED BY THE CITY. TESTING SHALL TAKEPLACE AFTER ALL UNDERGROUND UTILITIES ARE INSTALLED ANDCOMPACTION OF THE ROADWAY SUBGRADE IS COMPLETE.5. SPECIAL STRUCTURES, OIL/WATER SEPARATORS AND OUTLETCONTROLS SHALL BE INSTALLED PER PLANS ANDMANUFACTURERS' RECOMMENDATIONS. WHERE OIL/WATERSEPARATORS ARE CONNECTED TO A SEWER SYSTEM, THEYSHALL BE INSTALLED WITH A P-TRAP OR CHECK VALVE TOPREVENT ODORS.6. ALL DISTURBED AREAS SHALL BE STABILIZED IN ACCORDANCEWITH MINIMUM REQUIREMENT 2 OF THE LATEST EDITION OF THEDEPARTMENT OF ECOLOGY STORMWATER MANAGEMENTMANUAL FOR WESTERN WASHINGTON (SWMMWW). FOR SITESWHERE VEGETATION HAS BEEN PLANTED THROUGH HYDROSEEDING, THE FINANCIAL GUARANTEE WILL NOT BE RELEASEDUNTIL THE VEGETATION HAS BEEN THOROUGHLY ESTABLISHED.7. WHERE CONNECTIONS REQUIRE "FIELD VERIFICATION", THECONTRACTOR SHALL EXPOSE SUCH CONNECTION POINTS ANDFITTINGS 48 HOURS PRIOR TO DISTRIBUTING SHUTDOWNNOTICES.8. ANY CHANGES TO THE DESIGN SHALL FIRST BE REVIEWED ANDAPPROVED BY THE PROJECT ENGINEER AND THE CITY'S CIVILREVIEW ENGINEER.9. ALL STORM PIPE SHALL BE A MINIMUM OF 12-INCH DIAMETER FORMAINS AND CROSSINGS. WHEN PRIVATE STORMWATER (I.E. ROOF,LOT OR FOOTING DRAINS) CANNOT BE INFILTRATED ONINDIVIDUAL LOTS, THE MINIMUM STANDARD PIPING CONNECTIONTO THE PUBLIC SYSTEM SHALL BE 8-INCH PVC. THE 8-INCH MAINUSED FOR CONNECTION SHALL BEGIN AT THE RIGHT-OF-WAY,AND THE CONNECTION TO THE CATCH BASIN OR MANHOLESHALL BE CORED AND GROUTED.10. ALL STORM MAINS AND RETENTION/DETENTION AREAS SHALL BESTAKED FOR GRADE AND ALIGNMENT BY AN ENGINEERING ORSURVEY FIRM LICENSED TO PERFORM SUCH WORK.11. THE MINIMUM STAKING OF STORM SEWER SYSTEMS SHALL BE INACCORDANCE WITH SECTION 3.00.050 OF THESE STANDARDS,AND AS FOLLOWS:A. STAKE LOCATION OF ALL CATCH BASINS, MANHOLES ANDOTHER FIXTURES FOR GRADE AND ALIGNMENT.B. STAKE LOCATION, SIZE, AND DEPTH OF RETENTION/DETENTIONFACILITY.C. STAKE FINISHED GRADE OF ALL STORMWATER FEATURES,INCLUDING BUT NOT LIMITED TO CATCH BASIN/MANHOLE RIMELEVATIONS, OVERFLOW STRUCTURES, WEIRS, AND INVERTELEVATIONS OF ALL PIPES IN CATCH BASINS, MANHOLES, ANDPIPES THAT DAYLIGHT.12. PIPE MATERIALS USED FOR STORMWATER CONVEYANCE SHALLBE AS APPROVED BY THE CITY. PIPE SIZE, SLOPE, COVER, ETC.,SHALL BE AS SPECIFIED IN THE CITY OF YELM DEVELOPMENTGUIDELINES AND ENGINEERING STANDARDS.13. ALL DRIVEWAY CULVERTS SHALL BE OF SUFFICIENT LENGTH TOPROVIDE A MINIMUM 3:1 SLOPE FROM THE EDGE OF THEDRIVEWAY TO THE BOTTOM OF THE DITCH. CULVERTS SHALLHAVE BEVELED END SECTIONS TO MATCH THE SIDE SLOPE.14. IF DRAINAGE OUTLETS (STUB-OUTS) ARE TO BE PROVIDED FOREACH INDIVIDUAL LOT, THE STUB OUTS SHALL CONFORM TO THEFOLLOWING:A. EACH OUTLET SHALL BE LOCATED AT THE LOWEST ELEVATIONON THE LOT, TO SERVICE ALL FUTURE ROOF DOWNSPOUTS ANDFOOTING DRAINS, DRIVEWAYS, YARD DRAINS, AND ANY OTHERSURFACE OR SUBSURFACE. EACH OUTLET SHALL HAVEFREE-FLOWING, POSITIVE DRAINAGE TO AN APPROVED STORMWATER CONVEYANCE SYSTEM OR TO AN APPROVED OUTFALLLOCATION.B. OUTLETS ON EACH LOT SHALL BE LOCATED WITH A 5-FOOTHIGH, 2"X 4" STAKE MARKED "STORM" OR "DRAIN." THE STUB-OUTSHALL VISIBLY EXTEND ABOVE SURFACE LEVEL AND BE SECUREDTO THE STAKE.C. PIPE MATERIAL SHALL BE AS APPROVED BY THE CITY.D. DRAINAGE EASEMENTS ARE REQUIRED FOR DRAINAGESYSTEMS DESIGNED TO CONVEY FLOWS THROUGH INDIVIDUALLOTS.E. THE DEVELOPER AND/OR CONTRACTOR IS RESPONSIBLE FORCOORDINATING THE LOCATIONS OF ALL STUB-OUT CONVEYANCELINES WITH RESPECT TO THE UTILITIES (E.G., POWER, GAS,TELEPHONE, TELEVISION).F. ALL INDIVIDUAL STUB-OUTS SHALL BE PRIVATELY OWNED ANDMAINTAINED BY THE LOT HOMEOWNER.15. THE STORM DRAINAGE SYSTEM SHALL BE CONSTRUCTEDACCORDING TO APPROVED PLANS ON FILE WITH THE CITY. ANYMATERIAL DEVIATION FROM THE APPROVED PLANS WILLREQUIRE WRITTEN APPROVAL FROM THE CITY.16. ALL DISTURBED AREAS SHALL BE SEEDED AND MULCHED ORSIMILARLY STABILIZED TO THE SATISFACTION OF THE CITY. FORSITES WHERE GRASS HAS BEEN PLANTED THROUGH HYDROSEEDING, THE PERFORMANCE BOND WILL NOT BE RELEASEDUNTIL THE GRASS HAS BEEN THOROUGHLY ESTABLISHED, UNLESSOTHERWISE APPROVED BY THE CITY.17. ALL BUILDING DOWNSPOUTS ON COMMERCIAL SITES SHALL BECONNECTED TO THE STORM DRAINAGE SYSTEM, UNLESSOTHERWISE APPROVED BY THE CITY.18. ALL EROSION CONTROL AND STORMWATER FACILITIES SHALL BEREGULARLY INSPECTED AND MAINTAINED BY THE CONTRACTORDURING THE CONSTRUCTION PHASE OF THE DEVELOPMENTPROJECT.19. NO FINAL CUT OR FILL SLOPE SHALL EXCEED TWO (2)HORIZONTAL TO ONE (1) VERTICAL WITHOUT STABILIZATION BYROCKERY OR BY A STRUCTURAL RETAINING WALL.20. THE PROJECT ENGINEER SHALL VERIFY THE LOCATIONS, WIDTHS,THICKNESSES, AND ELEVATIONS OF ALL EXISTING PAVEMENTSAND STRUCTURES, INCLUDING UTILITIES AND OTHER FRONTAGEIMPROVEMENTS, THAT ARE TO INTERFACE WITH NEW WORK,AND PROVIDE ALL TRIMMING, CUTTING, SAW CUTTING, GRADING,LEVELING, SLOPING, COATING, AND OTHER WORK, INCLUDINGMATERIALS NECESSARY TO CAUSE THE INTERFACE WITHEXISTING WORKS TO BE PROPER, WITHOUT CONFLICT,ACCEPTABLE TO THE PROJECT ENGINEER AND THE CITY'S CIVILREVIEW ENGINEER, COMPLETE IN PLACE, AND READY TO USE.21. COMPACTION OF ALL FILL AREAS SHALL BE PER CURRENT APWASPECIFICATIONS. FILL SHALL BE PROVIDED IN 6" MAXIMUM LIFTSAND SHALL BE COMPACTED TO 95 PERCENT OF ITS MAXIMUMRELATIVE DENSITY.STORMWATER GENERAL NOTES (CITY)NAVD 88 PER RTK GPS TIES AND THE WASHINGTON STATE REFERENCENETWORK (WSRN). UNITS OF MEASUREMENT ARE U.S. SURVEY FEET.VERTICAL DATUMLOTS 1 AND 2 IN BLOCK 9 OF SOLBERG'S FIRST ADDITION TO YELM, ASRECORDED IN VOLUME 9 OF PLATS, PAGE 31; IN THURSTON COUNTY,WASHINGTON.LEGAL DESCRIPTION1.ALL WORKMANSHIP AND MATERIALS SHALL BE IN ACCORDANCEWITH CITY OF YELM STANDARDS, AND THE MOST CURRENT COPYOF THE STATE OF WASHINGTON STANDARD SPECIFICATIONS FORROAD, BRIDGE, AND MUNICIPAL CONSTRUCTION.2.THE CONTRACTOR SHALL BE RESPONSIBLE FOR ALL TRAFFICCONTROL IN ACCORDANCE WITH MUTCD. PRIOR TO DISRUPTIONOF ANY TRAFFIC, TRAFFIC CONTROL PLANS SHALL BE PREPAREDAND SUBMITTED TO THE CITY FOR APPROVAL. NO WORK SHALLCOMMENCE UNTIL ALL APPROVED TRAFFIC CONTROL IS IN PLACE.3.ALL CURB AND GUTTER, STREET GRADES, SIDEWALK GRADES,AND ANY OTHER VERTICAL AND/OR HORIZONTAL ALIGNMENTSHALL BE STAKED BY AN ENGINEERING OR SURVEYING FIRMCAPABLE OF PERFORMING SUCH WORK.4.WHERE NEW ASPHALT JOINS EXISTING, THE EXISTING ASPHALTSHALL BE CUT TO A NEAT VERTICAL EDGE AND TACKED WITHASPHALT EMULSION TYPE CSS1 IN ACCORDANCE WITH THESTANDARD SPECIFICATIONS. THE NEW ASPHALT SHALL BEFEATHERED BACK OVER EXISTING TO PROVIDE FOR A SEAL ATTHE SAW CUT LOCATION AND THE JOINT SEALED WITH GRADEAR-4000W PAVING ASPHALT.5.COMPACTION OF SUBGRADE, ROCK, AND ASPHALT SHALL BE INACCORDANCE WITH THE STANDARD SPECIFICATIONS.6.SUBGRADE INSPECTION SHALL BE PERFORMED BY AN APPROVEDTESTING FIRM AND FORMS SHALL BE INSPECTED FOR LINE ANDGRADE BY AN ENGINEER BEFORE POURING CONCRETE.7.CERTIFICATION AS TO CONFORMANCE SHALL BE PROVIDED TOTHE CITY PRIOR TO ACCEPTANCE OF WORK.8.THE CONTRACTOR/DEVELOPER SHALL FURNISH AND INSTALL ALLPERMANENT SIGNING.STREET CONSTRUCTION NOTESUTILITY LOCATE NOTETHE LOCATION OF EXISTING UTILITIES SHOWN HEREON AREAPPROXIMATE AND ARE BASED ON INFORMATION PROVIDED BY THESURVEYOR AND FROM COUNTY RECORDS. OLYMPIC ENGINEERINGASSUMES NO RESPONSIBILITY FOR THE EXACT LOCATION OF EXISTINGUTILITIES SHOWN OR NOT SHOWN HEREON CONTRACTOR SHALLVERIFY THE EXACT SIZE, DEPTH, AND LOCATION OF EXISTING UTILITIESAND CALL FOR UNDERGROUND LOCATE AT 811 A MINIMUM OF48-HOURS PRIOR TO CONSTRUCTION START. CONTRACTOR SHALL BEFULLY RESPONSIBLE FOR ANY AND ALL DAMAGES RESULTING FROMFAILURE TO LOCATE EXISTING UTILITIES.
COCOPMTPMT0.2'0.6'5.6'6.4'S49° 29' 55"E100.01'S40° 30' 51"W120.00'N49° 30' 11"W100.02'N40° 31' 05"E 120.00'N:594289.55E:1113365.82N:594337.44E:1113406.75N:594312.39E:1113436.07N:594301.06E:1113454.03N:594274.85E:1113375.32N:594250.72E:1113355.76N:594232.94E:1113376.29N:594266.95E:1113455.68N:594364.78E:1113408.03N:594208.60E:1113406.123+00 4+00 4+10STA: 3+80.30OFF: 17.76STA: 3+59.63OFF: 11.00STA: 3+36.63OFF: 11.00STA: 3+16.63OFF: 18.00STA: 2+89.08OFF: 18.00STA: 2+61.53OFF: 18.00STA: 4+10.01OFF: 0.00N40° 31' 05"E 310.01'FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
SITE AND HORIZONTAL
CONTROL PLAN SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC229123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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INEER T461131
2
-
2
2-2022 9' TYP20' TYP23'
11.1'9'
5'
8'
8'8'8'6'5'
9'8.8'18'KEY NOTES1.PROPOSED ASPHALT CEMENT CONCRETE PER PAVEMENT NOTES2.PROPOSED REVEGETATION TO LAWN. REMOVE GRAVEL. SCARIFYSUBGRADE TO 4" DEPTH, AND APPLY THE POST CONSTRUCTION SOILQUALITY AND DEPTH DETAIL 2/C63.PROPOSED PORTLAND CEMENT CONCRETE PAVEMENT PERPAVEMENT NOTES. SIDEWALKS SHALL BE PER DETAIL 1/C6.4.PROPOSED MONUMENT SIGN TO BE REPLACED UNDER SEPARATEPERMIT (42 SF EACH SIDE)5.PROPOSED WHEEL STOP PER DETAIL 2/C8 (TYP)6.PROPOSED ADA STALL AND SIGN PER DETAILS 3,4/C67.PROPOSED PARKING STALL MARKING. 4" DOUBLE-COATED WHITELINES. (TYP)8.PROPOSED 45-DEGREE DIAGONAL 4" DOUBLE-COATED WHITE LINESAT 24" ON CENTER9.PROPOSED PARKING LOT LANDSCAPING PER SEPARATE LANDSCAPEPLANS. 309 SF10.PROPOSED WOOD ADA RAMP. ASSUMED 30" RISE OVER 30' RUN. SEESEPARATE BUILDING PLANS.11.PROPOSED DECK REPLACEMENT. SEE SEPARATE BUILDING PLANS.12.PROPOSED STAIRS. SEE SEPARATE BUILDING PLANS.13.PROPOSED PERIMETER LANDSCAPING. SEE SEPARATE LANDSCAPINGPLANS.14.EXISTING ASPHALT PAVEMENT TO REMAIN.15.PROPOSED SINGLE-DIRECTION CURB RAMP WITH TRUNCATED DOMESPER DETAILS 1,2/C816.PROPOSED CONCRETE BARRIER CURB AND GUTTER PER DETAIL 1/C817.INSTALL 4" WIDE PAINTED WHITE STRIPING LINES FOR ON-STREETPARALLEL PARKING STALLS (2 TOTAL) AS SHOWN.#PAVEMENT NOTESONSITE ASPHALT CEMENT CONCRETE (ACC) PAVEMENT SECTION SHALL BE12" OF COMPACTED SUBGRADE UNDER 6" OF CRUSHED SURFACING BASECOURSE (CSBC) UNDER 3" OF CRUSHED SURFACING TOP COURSE (CSTC)UNDER 3" OF ACC.OFFSITE ACC SECTION SHALL BE PER DETAIL 3/C7PORTLAND CEMENT CONCRETE (PCC) SECTION FOR SIDEWALKS SHALL BE 6"OF COMPACTED SUBGRADE UNDER 6" OF CSBC UNDER 4" OF PCCPROVIDE EMULSIFIED ASPHALT GRADE CSS-1 TACK COAT ALONG SAWCUTEDGE WHERE APPLICABLE. MATCH TO EXISTING ASPHALT GRADES.SW RICE ST
YELM AVE SEALLEY112334SCALE IN FEET201006789101112131313144'EXISTINGBUILDINGCHANGING TOSERVICE-ORIENTEDUSE(1 STORY)(483 SF)EXISTINGSERVICE-ORIENTEDBUILDINGTO BE IMPROVED(2 STORIES)(990 SF)5.5'0.5'5.6'20'30'R35'NAD 1983(2011) SOUTH ZONE; PER RTK GPS TIES AND THE WASHINGTON STATEREFERENCE NETWORK (WSRN). UNITS OF MEASUREMENT ARE U.S. SURVEYFEET.HORIZONTAL DATUM1515163C711'517
WWWWWWWWWWWWWWWWWWW W W W W W W W W W W W W W W W W W W W W W WCO
COPMTPMTCONC WALKEXISTINGBUILDINGEXISTINGGARAGECONC WALKGRAVELGRAVELGRAVELASPHALTDRIVECONCCONCBLOCKWALLCONCBLOCKWALLEXISTINGBUILDINGEDGE OF ASPHALTCURBEDGE OF ASPHALTEDGE OF ASPHALT
EDGE OF ASPHALTEDGE OF ASPHALTROOF PEAKEL==372.18'F.F.E.=353.29'EXISTINGSHED0.2'0.6'5.6'6.4'SSFILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DEMOLITION & TESC PLAN SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC339123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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INEER T461131
2
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2
2-2022 1234567KEY NOTES1.EXISTING ASPHALT CEMENT CONCRETE (ACC) DRIVEWAY. USE ASCONSTRUCTION ENTRANCE.2.DEMOLISH AND DISPOSE OF EXISTING PORTLAND CEMENT CONCRETE(PCC) SIDEWALK3.DEMOLISH AND DISPOSE OF EXISTING PCC SIDEWALK4.PROTECT EXISTING PCC SIDEWALK5.DEMOLISH AND DISPOSE OF EXISTING SIGN AND ASSOCIATEDCONCRETE BLOCKS6.PROTECT EXISTING TREE TO REMAIN (TYP)7.SAWCUT, REMOVE, AND DISPOSE OF EX. ASPHALT AS SHOWN.REMOVE EXISTING ROAD SECTION AS NEEDED TO ACCOMMODATENEW 4" DEPTH OF PAVEMENT. SEE RICE ST. SECTION DETAIL 3/C8.CONTRACTOR SHALL CONTACT THE GEOTECHNICAL ENGINEER ANDCITY PUBLIC WORKS INSPECTOR TO INSPECT EXISTING SUBGRADEPRIOR TO INSTALLATION OF THE ROADWAY SECTION. CONTRACTORSHALL PROVIDE A MIN. 48-HOUR NOTICE.(TYP)8.PROPOSED LIMITS OF DISTURBANCE9.PROTECT EXISTING WATER MAIN10.PROTECT EXISTING GAS LINE#SCALE IN FEET201008SW RICE ST
YELM AVE SEALLEY773910INSTALL AND MAINTAIN INLET PROTECTION SILT SOCK AT ALLPROPOSED CATCH BASINS.NOTES
WWWWWWWWWWWWWWWWWWW W W W W W W W W W W W W W W W W W WCOCO
PMTPMT0.2'0.6'5.6'6.4'SSRD RD
RD RD
RDRDRDRDRDRD RD
RDRDRDRDRD SD SDOHPOHPOHPOHPOHPOHP
SSSSSSSSSSSSSSSSSS SS
WWWWWWW WSD SD SD SD SDSDSD3523513503503513
5
2 352350350350349350 351 3523493503493503493503513403453503553403453503552+202+252+50350.02+75350.4350.26
3+00351.0
350.60
3+25351.4
351.09
3+50351.8
351.52
3+75351.62
4+001.87%1.43%1.60%1.92%1.79%2.14%1.94%1.45%1.91%0.43%0.34%FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
STORMWATER & UTILITY PLAN SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC449123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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2
2-2022
SW RICE ST
YELM AVE SEALLEYKEY NOTES1.PROPOSED INFILTRATION GALLERY PER DETAILS 5/C6 AND 1,2/C72.PROPOSED BAY FILTER CATCH BASIN PER DETAIL 3/C7RIM: 348.6212" IE (NE): 342.8812" IE (NW): 344.8812" IE (SE): 345.903.PROPOSED 3 LF 12" SDR35 PVC STORM DRAIN AT 0.005 FT/FT4.PROPOSED 20LF 6" SDR35 PVC STORM DRAIN AT 0.020 FT/FT5.PROPOSED FLOWLINE PROFILE6.IE: 342.867.PROPOSED INSPECTION PORT PER DETAIL 4/C78.PROPOSED ROOF DRAIN CLEANOUT PER DETAIL 6/C6 AND STORM DRAIN NOTES.9.PROPOSED ROOF DRAIN LINE PER DETAIL 6/C6 AND ROOF AND STORM DRAIN NOTES.10.EXISTING OVERHEAD POWER TO BE RELOCATED11.PROPOSED OVERHEAD POWER12.PROPOSED 1.25" CL200 PVC OR HDPE GRINDER PUMP LINE TO BE 18" DEEPER THAN PARALLEL ORCROSSING WATER LINE. IF THIS SEPARATION CANNOT BE MET, THE GRINDER PUMP LINE AND WATER LINESHALL BE BACKFILLED WITH CONTROLLED DENSITY FILL 6" ALL SIDES.13.PROPOSED 3/4" CL200 PVC WATER LINE14.PROPOSED GRINDER PUMP (DESIGN BY OTHERS)15.PROPOSED POWER POLE16.EXISTING WATER METER17.EXISTING GRAVITY SEWER CLEANOUT18.EXISTING GAS LINE. DEPTH AND MATERIAL UNKNOWN. DO NOT DAMAGE DURING CONSTRUCTION.19.EXISTING ROOF AREA (484 SF)20.EXISTING ROOF AREA (1,003 SF)21.EXISTING 10" WATER MAIN; DEPTH TO CROWN ASSUMED TO BE 3'. VERIFY 3' BURIAL DEPTH PRIOR TOCONSTRUCTION.22.PROPOSED TYPE 1 CATCH BASIN W/ GRATE PER DETAIL 4/C8RIM: 350.1212" IE (NE): 347.6223.PROPOSED 42 LF 12" SDR35 PVC STORM DRAIN AT 0.005 FT/FT24.PROPOSED 48" TYPE 2 CATCH BASIN W/ GRATE PER DETAIL 3/C9RIM: 350.6912" IE (SW): 347.4012" IE (SE): 345.0725.PROPOSED 42 LF 12" SDR35 PVC STORM DRAIN AT 0.005 FT/FT26.EXISTING CENTERLINE GRADE27.MAINTAIN 6" VERTICAL SEPARATION BETWEEN WATER MAIN AND PROPOSED STORM DRAIN. PROVIDEASTM C33 SAND CUSHION.28.PROPOSED TYPE 1 CATCH BASIN W/ GRATE PER DETAIL 4/C8RIM: 348.5912" IE (NW): 346.00#123467891011121314151617·EXISTING HARD SURFACE: 8,539 SF·NEW PLUS REPLACED HARD SURFACE:5,505 SF·HARD SURFACE AFTER PROJECT:9,721 SF·NEW + REPLACED POLLUTION GENERATING HARD SURFACE:8,233 SF·LAWN + LANDSCAPE AFTER PROJECT:5,738 SF·PROPOSED EFFECTIVE HARD SURFACE:0 SF·DISTURBED AREA:15,459 SFSITE COVERAGE DATA (WITHIN LOD)ROOF AND STORM DRAIN NOTES1.ROOF DRAIN PIPE SHALL BE SDR 35 PVC AND SHALL BE AT A MINIMUM 2% GRADE TO DRAIN TO DISCHARGELOCATION2.PIPE TRENCHING AND BACKFILL SHALL BE PER PIPE MANUFACTURER SPECIFICATIONS3.ALL PIPE SHALL BE CLEANED VIA FLUSHING PRIOR TO CONNECTION TO DISCHARGE LOCATION4.DRAIN FITTINGS SHALL BE SDR 35 PVC FITTINGS5.ROOF AND STORM DRAIN PIPE SHALL BE LAID STRAIGHT WITH NO SAGS OR BENDS IN PIPE. BENDS SHALLBE CONSTRUCTED WITH WATERTIGHT FITTINGS. 45-DEGREE WYE CLEANOUTS SHALL BE INSTALLEDUPSTREAM OF ALL BENDS AND SHALL BE PER DETAIL 6/C66.CONNECT ALL DOWNSPOUTS TO ROOF DRAINS WITH SDR 35 PVC FITTINGS PER DETAIL 6/C67.DO NOT CONNECT ROOF DRAIN PIPE TO FOOTING DRAIN PIPE18SCALE IN FEET2010019202122232425RICE ST PROFILEHORIZTONTAL 1"=20'VERTICAL 1"=5'12223242126272C76.5'13.2'NAD 1983(2011) SOUTH ZONE; PER RTK GPS TIES AND THEWASHINGTON STATE REFERENCE NETWORK (WSRN). UNITS OFMEASUREMENT ARE U.S. SURVEY FEET.HORIZONTAL DATUMNAVD 88 PER RTK GPS TIES AND THE WASHINGTON STATEREFERENCE NETWORK (WSRN). UNITS OF MEASUREMENT AREU.S. SURVEY FEET.VERTICAL DATUM285FLOWLINE ELEVATIONCENTERLINE ELEVATION
COCOPMTPMT352.39351.00350.02350.02350.02349.08349.07349.06348.92348.76348.84350.61350.52350.67350.58350.34350.43350.17350.15348.82348.99349.08348.59351.16351.06350.94351.03351.19351.28351.51351.60351.83351.933523513503503513
5
2 352350350350349350
351
352349350349350349350351350.66349.41349.43349.37349.41349.78349.82349.77349.73349.62349.96349.96351.68FL: 351.63TC: 352.13FL: 351.62TC: 352.12FL: 351.59TC: 352.09FL: 351.32TC: 351.82FL: 350.94TC: 351.44FL: 350.47TC: 350.97FL: 350.09TC: 350.59FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
GRADING PLAN SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC559123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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ASDAVIDAYLORSTAT
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INEER T461131
2
-
2
2-2022
SW RICE ST
YELM AVE SEALLEYSCALE IN FEET20100NAD 1983(2011) SOUTH ZONE; PER RTK GPS TIES AND THEWASHINGTON STATE REFERENCE NETWORK (WSRN). UNITS OFMEASUREMENT ARE U.S. SURVEY FEET.HORIZONTAL DATUMNAVD 88 PER RTK GPS TIES AND THE WASHINGTON STATEREFERENCE NETWORK (WSRN). UNITS OF MEASUREMENT AREU.S. SURVEY FEET.VERTICAL DATUMFL = FLOW LINE ELEVATIONTC = TOP OF CURB ELEVATION
FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DETAILS 1 SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC669123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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2
2-2022 DETAILNOT TOSCALE1POST CONSTRUCTION SOIL QUALITY AND DEPTH DETAILNOT TOSCALE2ADA SIGNDETAILNOT TOSCALE3ADA SYMBOL DETAILNOT TOSCALE4NOT TOSCALEROOF DRAIN DETAILNOT TOSCALEFINISHED GRADEINSERT INJECTION MOLDED,GASKETED SPIGOT BY BELL REDUCERTEE4" SDR35 PVC PIPE (TYP)90° BEND45° BENDDOWNSPOUT ADAPTERINSERTED IN RISERPIPEBUILDINGFACE6" SDR35 PVC PIPE45° WYECLEANOUT W/ THREADED CAP6515.75'50.23'12" x 12" ADS N-12 MANIFOLDINSPECTION PORTINSTALL ADSPLUS125 WOVEN GEOTEXTILE OVER BEDDING STONE AND UNDERCHAMBER FEET FOR SCOUR PROTECTION AT ALL CHAMBER INLET ROWSFROM BAY FILTERCATCH BASININ-SITU INFILTRATION TESTING OF THE NATIVE SUBGRADE AT THE BASE OF THE STORMWATER INFILTRATION/DETENTIONSYSTEM IS REQUIRED AFTER EXCAVATION TO SUBGRADE, AT THE OWNER'S EXPENSE. A CORRECTED/DESIGN INFILTRATIONRATE LESS THAN 6.5 INCHES PER HOUR WILL REQUIRE RE-SIZING OF THE INFILTRATION/DETENTION SYSTEM. CONTRACTORSHALL CONTACT AN INFILTRATION TESTING FIRM 7 DAYS PRIOR TO REACHING SUBGRADE TO SCHEDULE THE INFILTRATIONTESTING.INFILTRATION/DETENTION FACILITYDETAIL
FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DETAILS 2 SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC779123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
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2-2022 DETAILNOT TOSCALE1 DETAILNOT TOSCALE3 DETAILNOT TOSCALE2INSPECTION PORT DETAILNOT TOSCALE4BOTTOM ELEV = 342.36NOTE:SEE WSDOT STANDARD PLANS B-10.20-01B-30.90-01 FOR ACCESS AND STEP/LADDERLOCATION/ORIENTATION AND DETAILS.INLET ELEVATION: 345.90, 344.88OUTLET ELEVATION: 342.88RIM ELEVATION: 348.62344.8812"
FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DETAILS 3 SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC889123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
O
L
ASDAVIDAYLORSTAT
E
OFWASHINGTONREGISTEREDPROFESSIONALENG
INEER T461131
2
-
2
2-2022 DETAILNOT TOSCALE1 DETAILNOT TOSCALE3 DETAILNOT TOSCALE2 DETAILNOT TOSCALE430'
FILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DETAILS 4 SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC999123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
O
L
ASDAVIDAYLORSTAT
E
OFWASHINGTONREGISTEREDPROFESSIONALENG
INEER T461131
2
-
2
2-2022 DETAILNOT TOSCALE1 DETAILNOT TOSCALE3 DETAILNOT TOSCALE2
Appendix C
JW301 WWHM 12/22/2022 11:18:03 AM Page 2
General Model Information
Project Name:JW301 WWHM
Site Name:Wentworth
Site Address:
City:
Report Date:12/22/2022
Gage:Lake Lawrence
Data Start:1955/10/01
Data End:2008/09/30
Timestep:15 Minute
Precip Scale:0.857
Version Date:2021/08/18
Version:4.2.18
POC Thresholds
Low Flow Threshold for POC1:50 Percent of the 2 Year
High Flow Threshold for POC1:50 Year
Low Flow Threshold for POC2:50 Percent of the 2 Year
High Flow Threshold for POC2:50 Year
JW301 WWHM 12/22/2022 11:18:03 AM Page 3
Landuse Basin Data
Predeveloped Land Use
Entire Limits of Disturbance
Bypass:No
GroundWater:No
Pervious Land Use acre
A B, Forest, Flat 0.389
Pervious Total 0.389
Impervious Land Use acre
Impervious Total 0
Basin Total 0.389
Element Flows To:
Surface Interflow Groundwater
JW301 WWHM 12/22/2022 11:18:03 AM Page 4
Basin 2
Bypass:No
GroundWater:No
Pervious Land Use acre
A B, Forest, Flat 0.389
Pervious Total 0.389
Impervious Land Use acre
Impervious Total 0
Basin Total 0.389
Element Flows To:
Surface Interflow Groundwater
JW301 WWHM 12/22/2022 11:18:03 AM Page 5
Mitigated Land Use
Onsite and Offsite Infiltration Sizing Basin
Bypass:No
GroundWater:No
Pervious Land Use acre
A B, Lawn, Flat 0.1317
Pervious Total 0.1317
Impervious Land Use acre
ROOF TOPS FLAT 0.0341
DRIVEWAYS FLAT 0.2232
Impervious Total 0.2573
Basin Total 0.389
Element Flows To:
Surface Interflow Groundwater
Gravel Trench Bed 1 Gravel Trench Bed 1
JW301 WWHM 12/22/2022 11:18:03 AM Page 6
Treatment Sizing Basin
Bypass:No
GroundWater:No
Pervious Land Use acre
A B, Lawn, Flat 0.13
Pervious Total 0.13
Impervious Land Use acre
DRIVEWAYS FLAT 0.223
Impervious Total 0.223
Basin Total 0.353
Element Flows To:
Surface Interflow Groundwater
JW301 WWHM 12/22/2022 11:18:03 AM Page 7
Routing Elements
Predeveloped Routing
JW301 WWHM 12/22/2022 11:18:03 AM Page 8
Mitigated Routing
Gravel Trench Bed 1
Bottom Length:43.00 ft.
Bottom Width:15.75 ft.
Trench bottom slope 1:0 To 1
Trench Left side slope 0:0 To 1
Trench right side slope 2:0 To 1
Material thickness of first layer:0.5
Pour Space of material for first layer:0.4
Material thickness of second layer:2.5
Pour Space of material for second layer:0.65
Material thickness of third layer:0.5
Pour Space of material for third layer:0.4
Infiltration On
Infiltration rate:6
Infiltration safety factor:1
Total Volume Infiltrated (ac-ft.):45.168
Total Volume Through Riser (ac-ft.):0
Total Volume Through Facility (ac-ft.):45.168
Percent Infiltrated:100
Total Precip Applied to Facility:0
Total Evap From Facility:0
Discharge Structure
Riser Height:4 ft.
Riser Diameter:6 in.
Element Flows To:
Outlet 1 Outlet 2
Gravel Trench Bed Hydraulic Table
Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs)
0.0000 0.015 0.000 0.000 0.000
0.0556 0.015 0.000 0.000 0.094
0.1111 0.015 0.000 0.000 0.094
0.1667 0.015 0.001 0.000 0.094
0.2222 0.015 0.001 0.000 0.094
0.2778 0.015 0.001 0.000 0.094
0.3333 0.015 0.002 0.000 0.094
0.3889 0.015 0.002 0.000 0.094
0.4444 0.015 0.002 0.000 0.094
0.5000 0.015 0.003 0.000 0.094
0.5556 0.015 0.003 0.000 0.094
0.6111 0.015 0.004 0.000 0.094
0.6667 0.015 0.005 0.000 0.094
0.7222 0.015 0.005 0.000 0.094
0.7778 0.015 0.006 0.000 0.094
0.8333 0.015 0.006 0.000 0.094
0.8889 0.015 0.007 0.000 0.094
0.9444 0.015 0.007 0.000 0.094
1.0000 0.015 0.008 0.000 0.094
1.0556 0.015 0.008 0.000 0.094
1.1111 0.015 0.009 0.000 0.094
1.1667 0.015 0.010 0.000 0.094
1.2222 0.015 0.010 0.000 0.094
1.2778 0.015 0.011 0.000 0.094
JW301 WWHM 12/22/2022 11:18:03 AM Page 9
1.3333 0.015 0.011 0.000 0.094
1.3889 0.015 0.012 0.000 0.094
1.4444 0.015 0.012 0.000 0.094
1.5000 0.015 0.013 0.000 0.094
1.5556 0.015 0.014 0.000 0.094
1.6111 0.015 0.014 0.000 0.094
1.6667 0.015 0.015 0.000 0.094
1.7222 0.015 0.015 0.000 0.094
1.7778 0.015 0.016 0.000 0.094
1.8333 0.015 0.016 0.000 0.094
1.8889 0.015 0.017 0.000 0.094
1.9444 0.015 0.017 0.000 0.094
2.0000 0.015 0.018 0.000 0.094
2.0556 0.015 0.019 0.000 0.094
2.1111 0.015 0.019 0.000 0.094
2.1667 0.015 0.020 0.000 0.094
2.2222 0.015 0.020 0.000 0.094
2.2778 0.015 0.021 0.000 0.094
2.3333 0.015 0.021 0.000 0.094
2.3889 0.015 0.022 0.000 0.094
2.4444 0.015 0.023 0.000 0.094
2.5000 0.015 0.023 0.000 0.094
2.5556 0.015 0.024 0.000 0.094
2.6111 0.015 0.024 0.000 0.094
2.6667 0.015 0.025 0.000 0.094
2.7222 0.015 0.025 0.000 0.094
2.7778 0.015 0.026 0.000 0.094
2.8333 0.015 0.026 0.000 0.094
2.8889 0.015 0.027 0.000 0.094
2.9444 0.015 0.028 0.000 0.094
3.0000 0.015 0.028 0.000 0.094
3.0556 0.015 0.028 0.000 0.094
3.1111 0.015 0.029 0.000 0.094
3.1667 0.015 0.029 0.000 0.094
3.2222 0.015 0.030 0.000 0.094
3.2778 0.015 0.030 0.000 0.094
3.3333 0.015 0.030 0.000 0.094
3.3889 0.015 0.031 0.000 0.094
3.4444 0.015 0.031 0.000 0.094
3.5000 0.015 0.031 0.000 0.094
3.5556 0.015 0.032 0.000 0.094
3.6111 0.015 0.033 0.000 0.094
3.6667 0.015 0.034 0.000 0.094
3.7222 0.015 0.035 0.000 0.094
3.7778 0.015 0.036 0.000 0.094
3.8333 0.015 0.036 0.000 0.094
3.8889 0.015 0.037 0.000 0.094
3.9444 0.015 0.038 0.000 0.094
4.0000 0.015 0.039 0.000 0.094
4.0556 0.015 0.040 0.068 0.094
4.1111 0.015 0.041 0.184 0.094
4.1667 0.015 0.042 0.297 0.094
4.2222 0.015 0.042 0.369 0.094
4.2778 0.015 0.043 0.415 0.094
4.3333 0.015 0.044 0.454 0.094
4.3889 0.015 0.045 0.491 0.094
4.4444 0.015 0.046 0.524 0.094
4.5000 0.015 0.047 0.556 0.094
JW301 WWHM 12/22/2022 11:18:03 AM Page 10
4.5556 0.015 0.048 0.586 0.094
4.6111 0.015 0.049 0.615 0.094
4.6667 0.015 0.049 0.642 0.094
4.7222 0.015 0.050 0.669 0.094
4.7778 0.015 0.051 0.694 0.094
4.8333 0.015 0.052 0.718 0.094
4.8889 0.015 0.053 0.742 0.094
4.9444 0.015 0.054 0.765 0.094
5.0000 0.015 0.055 0.787 0.094
JW301 WWHM 12/22/2022 11:18:03 AM Page 11
Analysis Results
POC 1
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #1
Total Pervious Area:0.389
Total Impervious Area:0
Mitigated Landuse Totals for POC #1
Total Pervious Area:0.1317
Total Impervious Area:0.2573
Flow Frequency Method:Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #1
Return Period Flow(cfs)
2 year 0.00059
5 year 0.001637
10 year 0.003019
25 year 0.006165
50 year 0.010122
100 year 0.016191
Flow Frequency Return Periods for Mitigated. POC #1
Return Period Flow(cfs)
2 year 0
5 year 0
10 year 0
25 year 0
50 year 0
100 year 0
Annual Peaks
Annual Peaks for Predeveloped and Mitigated. POC #1
Year Predeveloped Mitigated
1956 0.002 0.000
1957 0.000 0.000
1958 0.000 0.000
1959 0.000 0.000
1960 0.000 0.000
1961 0.001 0.000
1962 0.000 0.000
1963 0.000 0.000
1964 0.000 0.000
1965 0.000 0.000
JW301 WWHM 12/22/2022 11:18:31 AM Page 12
1966 0.000 0.000
1967 0.001 0.000
1968 0.000 0.000
1969 0.000 0.000
1970 0.000 0.000
1971 0.003 0.000
1972 0.004 0.000
1973 0.000 0.000
1974 0.001 0.000
1975 0.000 0.000
1976 0.000 0.000
1977 0.000 0.000
1978 0.000 0.000
1979 0.000 0.000
1980 0.000 0.000
1981 0.001 0.000
1982 0.001 0.000
1983 0.000 0.000
1984 0.000 0.000
1985 0.000 0.000
1986 0.001 0.000
1987 0.001 0.000
1988 0.000 0.000
1989 0.000 0.000
1990 0.002 0.000
1991 0.003 0.000
1992 0.000 0.000
1993 0.000 0.000
1994 0.000 0.000
1995 0.002 0.000
1996 0.005 0.000
1997 0.003 0.000
1998 0.001 0.000
1999 0.000 0.000
2000 0.000 0.000
2001 0.000 0.000
2002 0.002 0.000
2003 0.000 0.000
2004 0.020 0.000
2005 0.003 0.000
2006 0.014 0.000
2007 0.006 0.000
2008 0.000 0.000
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #1
Rank Predeveloped Mitigated
1 0.0197 0.0000
2 0.0142 0.0000
3 0.0061 0.0000
4 0.0047 0.0000
5 0.0041 0.0000
6 0.0034 0.0000
7 0.0032 0.0000
8 0.0031 0.0000
9 0.0025 0.0000
10 0.0022 0.0000
11 0.0020 0.0000
JW301 WWHM 12/22/2022 11:18:31 AM Page 13
12 0.0019 0.0000
13 0.0019 0.0000
14 0.0014 0.0000
15 0.0011 0.0000
16 0.0008 0.0000
17 0.0007 0.0000
18 0.0007 0.0000
19 0.0007 0.0000
20 0.0007 0.0000
21 0.0005 0.0000
22 0.0004 0.0000
23 0.0004 0.0000
24 0.0004 0.0000
25 0.0003 0.0000
26 0.0003 0.0000
27 0.0003 0.0000
28 0.0003 0.0000
29 0.0003 0.0000
30 0.0003 0.0000
31 0.0003 0.0000
32 0.0003 0.0000
33 0.0003 0.0000
34 0.0003 0.0000
35 0.0003 0.0000
36 0.0003 0.0000
37 0.0003 0.0000
38 0.0003 0.0000
39 0.0003 0.0000
40 0.0003 0.0000
41 0.0003 0.0000
42 0.0003 0.0000
43 0.0003 0.0000
44 0.0003 0.0000
45 0.0003 0.0000
46 0.0003 0.0000
47 0.0003 0.0000
48 0.0003 0.0000
49 0.0003 0.0000
50 0.0003 0.0000
51 0.0003 0.0000
52 0.0003 0.0000
53 0.0003 0.0000
JW301 WWHM 12/22/2022 11:18:31 AM Page 14
Duration Flows
The Facility PASSED
Flow(cfs)Predev Mit Percentage Pass/Fail
0.0003 687 0 0 Pass
0.0004 148 0 0 Pass
0.0005 120 0 0 Pass
0.0006 98 0 0 Pass
0.0007 80 0 0 Pass
0.0008 61 0 0 Pass
0.0009 51 0 0 Pass
0.0010 48 0 0 Pass
0.0011 44 0 0 Pass
0.0012 38 0 0 Pass
0.0013 37 0 0 Pass
0.0014 33 0 0 Pass
0.0015 32 0 0 Pass
0.0016 30 0 0 Pass
0.0017 29 0 0 Pass
0.0018 27 0 0 Pass
0.0019 26 0 0 Pass
0.0020 22 0 0 Pass
0.0021 19 0 0 Pass
0.0022 18 0 0 Pass
0.0023 16 0 0 Pass
0.0024 16 0 0 Pass
0.0025 14 0 0 Pass
0.0026 13 0 0 Pass
0.0027 11 0 0 Pass
0.0028 9 0 0 Pass
0.0029 9 0 0 Pass
0.0030 9 0 0 Pass
0.0031 9 0 0 Pass
0.0032 8 0 0 Pass
0.0033 6 0 0 Pass
0.0034 5 0 0 Pass
0.0035 5 0 0 Pass
0.0036 5 0 0 Pass
0.0037 5 0 0 Pass
0.0038 5 0 0 Pass
0.0039 5 0 0 Pass
0.0040 5 0 0 Pass
0.0041 5 0 0 Pass
0.0042 4 0 0 Pass
0.0043 4 0 0 Pass
0.0044 4 0 0 Pass
0.0045 4 0 0 Pass
0.0046 4 0 0 Pass
0.0047 4 0 0 Pass
0.0048 3 0 0 Pass
0.0049 3 0 0 Pass
0.0050 3 0 0 Pass
0.0051 3 0 0 Pass
0.0052 3 0 0 Pass
0.0053 3 0 0 Pass
0.0054 3 0 0 Pass
0.0055 3 0 0 Pass
JW301 WWHM 12/22/2022 11:18:31 AM Page 15
0.0056 3 0 0 Pass
0.0057 3 0 0 Pass
0.0058 3 0 0 Pass
0.0059 3 0 0 Pass
0.0060 3 0 0 Pass
0.0061 3 0 0 Pass
0.0062 2 0 0 Pass
0.0063 2 0 0 Pass
0.0064 2 0 0 Pass
0.0064 2 0 0 Pass
0.0065 2 0 0 Pass
0.0066 2 0 0 Pass
0.0067 2 0 0 Pass
0.0068 2 0 0 Pass
0.0069 2 0 0 Pass
0.0070 2 0 0 Pass
0.0071 2 0 0 Pass
0.0072 2 0 0 Pass
0.0073 2 0 0 Pass
0.0074 2 0 0 Pass
0.0075 2 0 0 Pass
0.0076 2 0 0 Pass
0.0077 2 0 0 Pass
0.0078 2 0 0 Pass
0.0079 2 0 0 Pass
0.0080 2 0 0 Pass
0.0081 2 0 0 Pass
0.0082 2 0 0 Pass
0.0083 2 0 0 Pass
0.0084 2 0 0 Pass
0.0085 2 0 0 Pass
0.0086 2 0 0 Pass
0.0087 2 0 0 Pass
0.0088 2 0 0 Pass
0.0089 2 0 0 Pass
0.0090 2 0 0 Pass
0.0091 2 0 0 Pass
0.0092 2 0 0 Pass
0.0093 2 0 0 Pass
0.0094 2 0 0 Pass
0.0095 2 0 0 Pass
0.0096 2 0 0 Pass
0.0097 2 0 0 Pass
0.0098 2 0 0 Pass
0.0099 2 0 0 Pass
0.0100 2 0 0 Pass
0.0101 2 0 0 Pass
JW301 WWHM 12/22/2022 11:18:31 AM Page 16
Water Quality
Water Quality BMP Flow and Volume for POC #1
On-line facility volume:0 acre-feet
On-line facility target flow:0 cfs.
Adjusted for 15 min:0 cfs.
Off-line facility target flow:0 cfs.
Adjusted for 15 min:0 cfs.
JW301 WWHM 12/22/2022 11:18:31 AM Page 17
LID Report
JW301 WWHM 12/22/2022 11:19:00 AM Page 18
POC 2
+ Predeveloped x Mitigated
Predeveloped Landuse Totals for POC #2
Total Pervious Area:0.389
Total Impervious Area:0
Mitigated Landuse Totals for POC #2
Total Pervious Area:0.13
Total Impervious Area:0.223
Flow Frequency Method:Log Pearson Type III 17B
Flow Frequency Return Periods for Predeveloped. POC #2
Return Period Flow(cfs)
2 year 0.00059
5 year 0.001637
10 year 0.003019
25 year 0.006165
50 year 0.010122
100 year 0.016191
Flow Frequency Return Periods for Mitigated. POC #2
Return Period Flow(cfs)
2 year 0.096911
5 year 0.137457
10 year 0.168846
25 year 0.214078
50 year 0.252087
100 year 0.294028
Annual Peaks
Annual Peaks for Predeveloped and Mitigated. POC #2
Year Predeveloped Mitigated
1956 0.002 0.078
1957 0.000 0.154
1958 0.000 0.102
1959 0.000 0.095
1960 0.000 0.134
1961 0.001 0.069
1962 0.000 0.071
1963 0.000 0.140
1964 0.000 0.090
1965 0.000 0.101
1966 0.000 0.077
JW301 WWHM 12/22/2022 11:19:22 AM Page 19
1967 0.001 0.092
1968 0.000 0.058
1969 0.000 0.061
1970 0.000 0.072
1971 0.003 0.070
1972 0.004 0.095
1973 0.000 0.070
1974 0.001 0.142
1975 0.000 0.096
1976 0.000 0.082
1977 0.000 0.117
1978 0.000 0.095
1979 0.000 0.125
1980 0.000 0.071
1981 0.001 0.130
1982 0.001 0.095
1983 0.000 0.167
1984 0.000 0.095
1985 0.000 0.084
1986 0.001 0.117
1987 0.001 0.089
1988 0.000 0.049
1989 0.000 0.062
1990 0.002 0.283
1991 0.003 0.130
1992 0.000 0.092
1993 0.000 0.055
1994 0.000 0.088
1995 0.002 0.124
1996 0.005 0.113
1997 0.003 0.096
1998 0.001 0.150
1999 0.000 0.081
2000 0.000 0.093
2001 0.000 0.084
2002 0.002 0.100
2003 0.000 0.067
2004 0.020 0.263
2005 0.003 0.315
2006 0.014 0.152
2007 0.006 0.121
2008 0.000 0.153
Ranked Annual Peaks
Ranked Annual Peaks for Predeveloped and Mitigated. POC #2
Rank Predeveloped Mitigated
1 0.0197 0.3150
2 0.0142 0.2830
3 0.0061 0.2632
4 0.0047 0.1670
5 0.0041 0.1535
6 0.0034 0.1528
7 0.0032 0.1516
8 0.0031 0.1500
9 0.0025 0.1422
10 0.0022 0.1395
11 0.0020 0.1338
12 0.0019 0.1299
JW301 WWHM 12/22/2022 11:19:22 AM Page 20
13 0.0019 0.1298
14 0.0014 0.1245
15 0.0011 0.1237
16 0.0008 0.1214
17 0.0007 0.1172
18 0.0007 0.1166
19 0.0007 0.1131
20 0.0007 0.1023
21 0.0005 0.1009
22 0.0004 0.0997
23 0.0004 0.0959
24 0.0004 0.0957
25 0.0003 0.0955
26 0.0003 0.0952
27 0.0003 0.0951
28 0.0003 0.0947
29 0.0003 0.0945
30 0.0003 0.0935
31 0.0003 0.0920
32 0.0003 0.0917
33 0.0003 0.0900
34 0.0003 0.0890
35 0.0003 0.0884
36 0.0003 0.0843
37 0.0003 0.0841
38 0.0003 0.0819
39 0.0003 0.0810
40 0.0003 0.0779
41 0.0003 0.0771
42 0.0003 0.0715
43 0.0003 0.0714
44 0.0003 0.0706
45 0.0003 0.0699
46 0.0003 0.0698
47 0.0003 0.0694
48 0.0003 0.0671
49 0.0003 0.0616
50 0.0003 0.0611
51 0.0003 0.0576
52 0.0003 0.0546
53 0.0003 0.0487
JW301 WWHM 12/22/2022 11:19:22 AM Page 21
Duration Flows
Flow(cfs)Predev Mit Percentage Pass/Fail
0.0003 687 352736 51344 Fail
0.0004 148 329134 222387 Fail
0.0005 120 310363 258635 Fail
0.0006 98 295310 301336 Fail
0.0007 80 282301 352876 Fail
0.0008 61 271150 444508 Fail
0.0009 51 261114 511988 Fail
0.0010 48 252008 525016 Fail
0.0011 44 243830 554159 Fail
0.0012 38 236211 621607 Fail
0.0013 37 229520 620324 Fail
0.0014 33 222830 675242 Fail
0.0015 32 216883 677759 Fail
0.0016 30 211122 703740 Fail
0.0017 29 205918 710062 Fail
0.0018 27 200900 744074 Fail
0.0019 26 195882 753392 Fail
0.0020 22 191236 869254 Fail
0.0021 19 186961 984005 Fail
0.0022 18 182743 1015238 Fail
0.0023 16 178654 1116587 Fail
0.0024 16 174844 1092775 Fail
0.0025 14 171313 1223664 Fail
0.0026 13 167764 1290492 Fail
0.0027 11 164400 1494545 Fail
0.0028 9 161185 1790944 Fail
0.0029 9 158174 1757488 Fail
0.0030 9 155293 1725477 Fail
0.0031 9 152357 1692855 Fail
0.0032 8 149495 1868687 Fail
0.0033 6 146707 2445116 Fail
0.0034 5 144087 2881740 Fail
0.0035 5 141522 2830440 Fail
0.0036 5 139087 2781740 Fail
0.0037 5 136616 2732320 Fail
0.0038 5 134181 2683620 Fail
0.0039 5 131839 2636780 Fail
0.0040 5 129516 2590320 Fail
0.0041 5 127361 2547220 Fail
0.0042 4 125205 3130125 Fail
0.0043 4 123105 3077625 Fail
0.0044 4 121060 3026500 Fail
0.0045 4 119146 2978650 Fail
0.0046 4 117139 2928475 Fail
0.0047 4 115188 2879700 Fail
0.0048 3 113329 3777633 Fail
0.0049 3 111508 3716933 Fail
0.0050 3 109724 3657466 Fail
0.0051 3 108051 3601700 Fail
0.0052 3 106360 3545333 Fail
0.0053 3 104706 3490200 Fail
0.0054 3 103145 3438166 Fail
0.0055 3 101584 3386133 Fail
0.0056 3 100078 3335933 Fail
JW301 WWHM 12/22/2022 11:19:22 AM Page 22
0.0057 3 98554 3285133 Fail
0.0058 3 97123 3237433 Fail
0.0059 3 95711 3190366 Fail
0.0060 3 94261 3142033 Fail
0.0061 3 92905 3096833 Fail
0.0062 2 91585 4579250 Fail
0.0063 2 90321 4516050 Fail
0.0064 2 89076 4453800 Fail
0.0064 2 87831 4391550 Fail
0.0065 2 86549 4327450 Fail
0.0066 2 85303 4265150 Fail
0.0067 2 84114 4205700 Fail
0.0068 2 82980 4149000 Fail
0.0069 2 81791 4089550 Fail
0.0070 2 80657 4032850 Fail
0.0071 2 79542 3977100 Fail
0.0072 2 78427 3921350 Fail
0.0073 2 77331 3866550 Fail
0.0074 2 76290 3814500 Fail
0.0075 2 75212 3760600 Fail
0.0076 2 74227 3711350 Fail
0.0077 2 73242 3662100 Fail
0.0078 2 72257 3612850 Fail
0.0079 2 71309 3565450 Fail
0.0080 2 70417 3520850 Fail
0.0081 2 69525 3476250 Fail
0.0082 2 68614 3430700 Fail
0.0083 2 67741 3387050 Fail
0.0084 2 66812 3340600 Fail
0.0085 2 65957 3297850 Fail
0.0086 2 65102 3255100 Fail
0.0087 2 64266 3213300 Fail
0.0088 2 63485 3174250 Fail
0.0089 2 62705 3135250 Fail
0.0090 2 61887 3094350 Fail
0.0091 2 61088 3054400 Fail
0.0092 2 60363 3018150 Fail
0.0093 2 59564 2978200 Fail
0.0094 2 58802 2940100 Fail
0.0095 2 58077 2903850 Fail
0.0096 2 57352 2867600 Fail
0.0097 2 56627 2831350 Fail
0.0098 2 55903 2795150 Fail
0.0099 2 55215 2760750 Fail
0.0100 2 54546 2727300 Fail
0.0101 2 53895 2694750 Fail
The development has an increase in flow durations
from 1/2 Predeveloped 2 year flow to the 2 year flow
or more than a 10% increase from the 2 year to the 50
year flow.
The development has an increase in flow durations for
more than 50% of the flows for the range of the
duration analysis.
JW301 WWHM 12/22/2022 11:19:22 AM Page 23
Water Quality
Water Quality BMP Flow and Volume for POC #2
On-line facility volume:0.0328 acre-feet
On-line facility target flow:0.039 cfs.
Adjusted for 15 min:0.039 cfs.
Off-line facility target flow:0.0221 cfs.
Adjusted for 15 min:0.0221 cfs.
JW301 WWHM 12/22/2022 11:19:22 AM Page 24
LID Report
JW301 WWHM 12/22/2022 11:19:22 AM Page 25
Model Default Modifications
Total of 0 changes have been made.
PERLND Changes
No PERLND changes have been made.
IMPLND Changes
No IMPLND changes have been made.
JW301 WWHM 12/22/2022 11:19:22 AM Page 26
Appendix
Predeveloped Schematic
JW301 WWHM 12/22/2022 11:19:23 AM Page 27
Mitigated Schematic
Appendix D
1001 Cooper Point Rd SW, STE 140 PMB 108 | Olympia, WA 98502 | 360.481.9784 | CHeathman@MudBayGeotech.com
December 18, 2022 Job: 2102-THU
Page 1
Subject: Stormwater Infiltration Geotechnical Report
313 Yelm Ave W,
Yelm, WA 98597
Parcel # 75300900100
Dear Jennifer Wentworth,
This report presents the results of our geotechnical investigation and contains stormwater
infiltration rate recommendations for the site development project located at 313 Yelm Ave W in
Yelm, Washington. The analyses, conclusions, and recommendations in this report are based on
the information available. These informational resources include: one (1) excavated test pit and
one (1) small pilot infiltration test (Small PIT) completed specifically for the subject project, as well
as published geologic information for the site and vicinity and our experience with similar geologic
materials. The conditions observed in the exploration are assumed to be representative of the
subsurface conditions throughout the project area. If during construction, subsurface conditions
differ from those described in the exploration, we should be advised immediately so that we may
reevaluate our recommendations and provide further assistance.
SITE CONDITIONS AND PROJECT DESCRIPTION
Parcel # 75300900100 consists of a total of 0.28 acres in Yelm, Washington. The parcel location
has been given the situs address of 313 Yelm Ave W, and is identified on the Site Location Map
included as Figure 1 attached to this report. The property is located off the southwestern side of
Yelm Ave W, and can be accessed via a paved driveway along the northeastern margin of the
subject parcel. The site can also be accessed via a gravel alleyway parallel to the southwestern
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |2
parcel boundary, and from a gravel driveway off of Rice St SW. The site is currently being re-
developed with a renovated two-story structure, detached two-car garage, and an associated
paved parking area. Several large cedar trees exist across the parcel. The property consists of a
generally flat topography, along with the surrounding region.
The purpose of this report is to provide subsurface conditions and geotechnical recommendations
in regards to stormwater design within the subject parcel. The scope of the project is to re-develop
the parcel with a renovated two-story structure and garage along with an associated paved
parking area. A proposed site plan has not been provided and is currently unavailable at the time
of this report. Stormwater infiltration facilities are proposed as a flow control and treatment BMP
for the new impervious surface generated as part of the development. The parcel is located within
the jurisdiction of the City of Yelm; therefore, the stormwater and infiltration design requirements
of the Department of Ecology’s 2019 Stormwater Management Manual for Western Washington
must be satisfied. To meet the requirements for that method, we performed one (1) Small PIT to
characterize the infiltration rate of the site soils. This infiltration test was performed within the
upper ~2 to 3 feet based on the assumption shallow infiltration trenches, basins, swales, or rock
galleries will be used for treatment and flow control.
SITE GEOLOGY AND SOILS
As part of this project, we reviewed available geologic data and prepared a site-specific geologic
map. The project vicinity geologic map is attached as Figure 2, WA DNR Geologic Map. This
figure indicates the project vicinity consists of Pleistocene continental glacial drift. The DNR
describes these deposits as follows: Recessional and proglacial, stratified pebble, cobble, and
boulder gravel deposited in meltwater streams and their deltas; locally contains ice-contact
deposits. Conditions observed at the site are generally consistent with the mapped geology at the
site.
In addition to the site geology, site-specific soil data made available by the United States
Department of Agriculture was consulted. The USDA Soil Map is attached to this report as Figure
3. This figure suggests that the parcel is underlain by No. 110 – Spanaway gravelly sandy loam,
0 to 3 percent slopes. The USDA classifies the Spanaway series as follows: a somewhat
excessively draining, gravelly sandy loam to extremely gravelly sand sourced from volcanic ash
over gravelly outwash and deposited over terraces and outwash plains. The soils observed in-
situ are generally consistent with the mapped soils on-site. It should be noted that the slope
percentages displayed on the map are estimates and do not necessarily reflect true surface
topography.
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |3
SUBSURFACE EXPLORATION
To characterize the surface and subsurface conditions, Mud Bay Geotechnical Services, LLC
performed one (1) excavated test pit. This test pit was designated ITP-1-22, and was completed
on October 5, 2022. The excavated test pit was completed from the existing ground surface at
the approximate location shown on Figure 4, Site Exploration Map.
The test pit was completed using a Kubota KX040-0 compact excavator with Mud Bay
Geotechnical Services, LLC personnel onsite to perform and observe excavation, log the soils
encountered in the pit and collect samples.
The soil samples were classified visually in the field in general accordance with ASTM D2488,
the Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). Once
transported back to the office, the samples were re-examined, and the field classifications were
modified accordingly. A summary log of the excavated test pit is included in Appendix A. Note the
soil descriptions and interfaces shown on the log is interpretive, and actual changes may be
gradual. Upon completion, the test pit was backfilled to the original ground surface using
excavated material from the spoil piles.
SUBSURFACE SOIL AND GROUNDWATER CONDITIONS
Findings in the excavated test pit suggest the subsurface consists of approximately: an upper 6-
inches of moist, grey, crushed surfacing base coarse (CSBC), underlain by a moist, brown, silty
sand with gravel (SM) to a depth of 24-inches. Immediately below this was a final unit of moist,
tan, well-graded sand with silt and gravel (SW-SM) encountered to a depth of 84-inches below
ground surface. This final SW-SM soil unit appeared to be fairly compact as harder digging
condition were encountered, and is interpreted as native undisturbed glacial drift deposits.
The excavated test pit performed is assumed to be representative of the project area subsurface
conditions, however, the true nature of glacial deposits can be difficult to ascertain as they are
highly variable units. If conditions vary significantly during construction, we should be contacted
to reassess the recommendations included in this report.
Groundwater was not encountered during our subsurface exploration of the site on October 5,
2022. As a part of this project, well logs made available by the Washington State Department of
Ecology for the surrounding region were consulted. These well logs suggest that the depth to
groundwater in the area surrounding the subject property is greater than 20-feet below ground
surface and will not be encountered within the excepted limits of construction excavation.
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |4
FIELD MEASURED INFILTRATION TESTING
As part of the geotechnical investigation, a site reconnaissance and subsurface investigation was
performed on October 5, 2022, and a total of (1) one small pilot infiltration test (PIT) was
completed. This test pit, designated ITP-1-22 was excavated the day of testing to a depth near
the bottom of the proposed infiltration facility. A summary of the infiltration testing geometry for
the Small PIT is provided in Table 1 below.
Table 1: Small PIT Geometry
Small PIT Depth
(in.)
Top Width
(in.)
Top Length
(in.)
Basal Width
(in.)
Basal Length
(in.)
ITP-1-22 24 48 80 36 48
The infiltration testing was performed on October 5, 2022 following the general guidelines
established by the Department of Ecology’s 2019 Stormwater Management Manual for Western
Washington.
A vertical measuring stick of 3 ft height was placed within the center of the test pit to provide
measurements within ½” accuracy. The measuring stick was embedded a depth of 4 to 6 inches
into the infiltration subgrade to maintain stability during the testing. Water was introduced into the
pit using a garden hose. The bottom surface and sides of the pit were protected with a geotextile
fabric to reduce the potential for erosion and turbidity. The water was poured into the pit near the
original ground surface. After the pit was initially filled to a minimum depth of 12 inches, water
was introduced to the pit at a rate to maintain a water level of at least 12 inches above the base
of the pit during the 6-hour pre-soak period. The depth of water was recorded at selected times
during this period. A summary of the water level measurements is presented in Table 2.
Table 2: Pre -Soak Water Level Measurements
Approximate Time ITP-1-22 (in.)
8:20 12.0
9:20 13.0
10:20 12.0
11:20 11.5
12:20 12.0
13:20 12.0
14:20 12.0
The six-hour pre-soak period was concluded by one hour of steady state instantaneous flow
measurements. Cumulative volume and instantaneous flow rates (gallons/minute) were recorded
at time intervals of 15 minutes while attempting to maintain a stable water depth of 12 inches. The
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |5
instantaneous flow measurements were performed using a stopwatch and recording the time
required to fill up one gallon with water. The water flow rate was adjusted slightly in between flow
rate measurements to maintain as close to a steady state head of 12 inches in the pit as possible.
A summary of results from the one-hour steady state period are presented in Table 3.
Table 3: I TP-1-22 Steady State Measurements
ITP-1-21 Water
Depth (in.)
Flow Rate
(gal/min.)
Cumulative
Volume
(gal)
Infiltration
Rate
(in./hr.)
14:30 12.0 ------ ----- -----
14:45 12.0 1.94 29.03 15.52
15:00 12.0 1.92 57.88 15.42
15:15 12.0 1.94 86.91 15.52
15:30 12.0 1.91 115.57 15.33
Water was then shut off to perform the falling head portion of the testing and an infiltration rate
(inches/hour) was recorded at 15-minute increments for a period of one hour. Results from the
falling head portion of the testing are presented in Table 4.
Table 4: I TP-1-22 Falling Head Measurements
Approximate
Time
Water
Depth (in.)
Infiltration
Rate
(in./hr.)
15:30 12.0 -----
15:45 9.0 12.0
16:00 6.0 12.0
16:15 3.0 12.0
16:30 0.0 12.0
After the falling head period was concluded, the pit was excavated below the bottom of the
infiltration pit to investigate the infiltrating soil conditions, to observe the depth of saturation, to
look for natural groundwater, and to look for a non-infiltrating hardpan. The immediate underlying
soil conditions consisted of moist, tan, well-graded sand with silt and gravel (SW-SM). Mottling
was absent within the unit and the induration of the sediment was noted to be moderately
indurated. A glacial hardpan layer was encountered at approximately 78-inches below ground
surface in the subject parcel. This unit was comprised of a moist, tan, well-graded sand with silt
and gravel (SW-SM), and was noted to be highly indurated with large cobbles and boulders.
Groundwater seepage was observed horizontally at the geologic contact between the upper less
dense and underlying dense SW-SM soil unit from the previous infiltration testing. We interpret
the looser overlying SW-SM as native glacial outwash, exhibiting well-draining soil
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |6
characteristics.The excavation beyond the base of the test pit appears to indicate that any surface
water will infiltrate vertically through the overlying less compacted glacial outwash before
encountering the underlying, glacially overridden till where it will then travel horizontally along the
unit contact boundary.
GEOLOGIC HAZARD ASSESSMENT
Liquefaction Susceptibility
A map of liquefaction susceptibility developed by the Department of Natural Resources is
attached as Figure 5, Liquefaction Hazard Map. Soil liquefaction is a phenomenon whereby
saturated soil deposits temporarily lose strength and behave as a viscous fluid in response to
cyclic loading. These behaviors are most common in saturated, loose, sandy soils with lesser
impacts occurring in silty soils. Figure 5 indicates that the glacial deposits mapped across the
parcel are at very low risk of soil liquefaction, and MBGS concurs with this assessment.
Landslide Hazard
We performed a cursory review of the available online site information to determine the potential
for landslide hazards at the site. The Landslide Map available from the Washington State
Department of Natural Resources revealed no mapped landslide deposits near the project vicinity.
No indications of deep-seated landslide activity, past or present, were observed during our on-
site investigation nor during our review of online resources. It is our interpretation that the site is
underlain by competent glacial material at a relatively shallow depth. The landslide hazard map
has been omitted from this report.
The geomorphology (shape of the land) was analyzed during the site evaluation and compared
to the Light Detection and Ranging images (LiDAR) from the Washington State LiDAR portal.
LiDAR is a remote sensing method were light is pulsed down to the surface of the Earth and back
to a sensor. This methodology enables bare earth images of the surface to be analyzed for the
presence of geologic landforms. The most recent available LiDAR imagery of this site is included
as Figure 6 attached to this report, WA DNR LiDAR Map. The bare earth imagery highlights the
gently graded topography of the parcel and surrounding region, along with urban grading
activities. We conclude the onsite landslide hazard risk to be very low.
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |7
GEOTECHNICAL RECOMMENDATIONS
Stormwater Infiltration
Using the infiltration data collected during the steady state and the falling head infiltration testing,
a base rate of approximately 12.0 inches per hour was determined based on the average
infiltration rate recorded during the Small PIT. A correction factor of 0.5 was applied to this value
to determine the final recommended design infiltration rate of 6 inches per hour, which should be
used in the design of infiltration facilities at the site. This correction factor assumes a moderate
amount of maintenance over the lifetime of the infiltration facility. Based on the infiltration rates
within the Small PIT, onsite soil conditions, and our experience with similar geologic conditions,
we conclude that the site is well-draining, and that on-site infiltration is feasible.
RECOMMENDED ADDITIONAL SERVICES
Before construction begins, we recommend a copy of the draft plans and specifications prepared
for the project are made available for review so that we can ensure that the geotechnical
recommendations in this report are included in the Contract. Mud Bay Geotechnical Services,
LLC is also available to provide geotechnical engineering and construction monitoring services
throughout the remainder of the design and construction of the project. The integrity of the
geotechnical elements of a project depend on proper site preparation and construction
procedures. In addition, engineering decisions may need to be made in the field if conditions are
encountered that differ from those described in this report. During the construction phase of the
project, we recommend that Mud Bay Geotechnical Services, LLC be retained to review
construction proposals and submittals, excavation and fill placement, drainage installation,
foundation subgrade preparation, and provide recommendations for any other geotechnical
considerations that may arise during construction.
INTENDED USE AND LIMITATIONS
This report was prepared based on observations of the surface and subsurface conditions at the
site, review of geology and other information available for the site, and conversations with the
property owner about the soil and surface water conditions on the property and the nature of the
proposed development. The geotechnical recommendations in this report are based on the
current site conditions and understanding of the proposed development as described previously.
Any modification of the current property conditions or the nature of the proposed development
beyond what is described in this report would render these geotechnical recommendations invalid.
2 102-T H U : 3 1 3 Y e l m A v e W , Y e l m WA 9 8 5 9 7 P a g e |8
It should not be used, in part or in whole for other purposes without contacting Mud Bay
Geotechnical Services, LLC for a review of the applicability of such reuse.
We have enjoyed the opportunity to work with you and serve your geotechnical needs for the
permitting phase of this project. Please contact me at your earliest convenience if you have any
questions or would like to discuss any of the content of this report.
Sincerely,
Chris Heathman, P.E.
Mud Bay Geotechnical Services, LLC
Legend
Approximate Site Location
Figure 1: Site Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Approximate Parcel Boundary
Legend
Figure 2: WA DNR Geologic Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Geologic Units 100k
Pleistocene continental glacial
drift
Sources: Esri, USGS | WA State Parks GIS, Esri, HERE, Garmin, FAO, NOAA, USGS, Bureau of Land Management, EPA, NPS | Washington Geological
Survey, 2019, Surface geology, 1:24,000--GIS data, November 2019: Washington Geological Survey Digital Data Series DS-10, version 3.1.
N
Approximate Parcel Boundary
Legend
Figure 3: USDA Soil Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Approximate Parcel Boundary
Legend
Approximate Test Pit Location
ITP-1-22
Figure 4: Site Exploration Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Approximate Parcel Boundary
Figure 5: Liquefaction Hazard Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Legend
Approximate Parcel Boundary
Liquefaction Susceptibility
Moderate
Low to Moderate
Moderate to High
Low
High
Very Low to Low
Very Low
Bedrock
Peat
Sources: Esri, USGS | WA State Parks GIS, Esri, HERE, Garmin, FAO, NOAA, USGS, Bureau of Land Management, EPA, NPS | Palmer, Stephen P.;
Magsino, Sammantha L.; Bilderback, Eric L.; Poelstra, James L.; Folger, Derek S.; Niggemann, Rebecca A., 2007, Liquefaction susceptibility and site
class maps of Washington State, by county: Washington Division of Geology and Earth Resources Open File Report 2004-20, [78 plates, 45 p. text].
N
Figure 6: WA DNR LiDAR Map
313 Yelm Ave W,
Yelm, WA 98597
Infiltration - Geotechnical Report
JOB #: 2102-THU Date: Dec. 2022
Sources: Esri, USGS | WA State Parks GIS, Esri, HERE, Garmin, FAO, NOAA, USGS, Bureau of Land Management, EPA, NPS | Washington Geological
Survey
N
Legend
Approximate Parcel Boundary
APPENDIX A – FINAL TEST PIT LOGS
Completed:Hammer Type:
Hammer Weight:
Groundwater Depth:
Lithology
Moist, grey, crushed surfacing base coarse (CSBS).
Transition: Moist, brown, silty sand with gravel (SM).
Transition: Moist, tan, well-graded sand with silt and gravel (SW-SM).
Moist, tan, well-graded sand with silt and gravel (SW-SM).
Base of Small PIT 24". Continued excavation after testing.
Very hard digging encountered. Water seepage from sidewalls of pit.
Grain size increasing with depth. Cobbles and boulders 2+ feet in size.
Interpreted as glacial drift hardpan. Test pit terminated.
Test Pit and Boring Log Symbols
Standard Penetration Slit Spoon Sampler (SPT)
California Sampler Blows/3/4"Density
Shelby Tube 0-4 Very Loose
CPP Sampler 5-10 Loose
StabIlized Ground water 11-24 Medium Dense
Groundwater At time of Drilling 25-50 Dense
Bulk/ Bag Sample REF Very Dense
Helper:Elevation:
n/a n/a
Fluid:
Backfilled:
Total Depth of Test Pit:
Address:DateStarted:Bit Type:Diameter:
313 Yelm Ave W,
Yelm, WA 98597
10/5/2022
10/5/2022 n/a n/a
Logged By:
Hannah Anderson 10/5/2022 n/a n/a
Hammer Drop:
Project:Client:Test Pit No. 1 of 1:
Stormwater Infiltration Jennifer Wentworth ITP-1-22
Project Number: Contractor: Equipment:
2102-THU Keystone Masonry INC.Kubota KX040-4
Tim Gollan n/a Existing Surface 84 inches
Depth (in.)Sample TypeSample NumberBlow Counts (blows/3/4")Graphic LogDry Density (pcf)Moisture Content (%)Additional TestSoil Group Name: modifier, color, moisture, density/consistency, grain size, other
descriptors
Rock Description: modifier, color, hardness/degree of concentration, bedding and joint
characteristics, solutions, void conditions.
GPS Method:
n/a
>60 Very Hard
5-8 Medium Stiff
9-15 Stiff
16-30 Very Stiff
31-60 Hard
GPS Coordinates:
(± __ ft.)
GPS Elevation:
(± __ ft.)
2-4 Soft
Soil Density Modifiers
Blows/3/4"Consistency
0-1 Very Soft
Gravel, Sand, Non-Plastic Silt Elastic Silts and Clays
Moist, tan, well-graded sand with silt and gravel (SW-SM).
24"S-1
78''
n/a
48''
84''
S-2 n/a
Appendix E
5
configuration of the BayFilter maximizes a media filter’s area
potential. The particle size of the media is also important with
respect to pollutant interception and adsorption. A tightly
packed, fine media (fig 2) captures a greater percentage of
fine and dissolved pollutants when compared to a loosely
packed, coarse media or a membrane media. A fine and
tightly packed media not only minimizes the interstitial
spaces between the media particles to optimize interception
of pollutants, it also maximizes the amount of surface area
in a given volume provided by the media for ion exchange.
The quantity of sediment a filter is capable of capturing is
a significant component to filter longevity. A filter must be
able to treat large quantities of sediment while maintaining
claimed flow rates and removal efficiencies. The sediment
loading capacity of the BayFilter is 350 pounds (158.7 kg) for
the 45 gpm (170.3 lpm) and 30 gpm (113.6 lpm) cartridges.
Surface area and loading rate contribute significantly to filter
longevity. Greater filter surface area (sf) allows for a reduced
loading rate (gpm/sf of filter media), which in turn increases the
service life of the filter. For example, a 10 square foot (0.9 m2)
filter with a loading rate of 1 GPM (3.8 l/min) per square foot
of filter area will pass 10 GPM (37.9 l/min). A 20 ft2 filter with a
loading rate of 0.5 GPM (1.9 l/min) per square foot of filter area
will also pass 10 GPM (37.9 l/min). If one gallon of treated water
will occlude one square foot of filter area every 10 days, a 10 ft2
(0.9 m2) filter flowing at one GPM (3.8 l/min) will be expired in
100 days. A 20 ft2 (1.9 m 2) filter flowing at 0.5 GPM (1.9 l/min)
will be expired in 400 days. Increasing media area and
reducing flow rate has a beneficial impact on pollutant removal
and filter longevity and these are some of the core engineering
principles on which the BayFilter design is based.
BaySaver Technologies is committed to the purpose of
protecting public waterways. Permanently capturing
pollutants, effectively backwashing media, allowing media to
drain between storm events, and providing an economically
reasonable maintenance interval are key design parameters
for properly functioning stormwater filtration systems. The
BayFilter cartridge system helps meet and exceed these
key requirements needed to protect our water resources.
Bottom of Cartridge
Top of Cartridge
Appendix F
1
Wentworth Commercial Development
Construction Stormwater Pollution Prevention
Plan
Date of Preparation
11/5/22
Project Location
313 Yelm Ave W
Yelm, WA 98597
Thurston County TPN: 75300900100
Applicant/Owner
Jennifer Wentworth
wentworthje@gmail.com
Project engineer
Nicholas Taylor, PE
Iris Group PLLC
(360) 890-8955
ntaylor@irisgroupconsulting.com
Contractor/Contact
Steve Borman
253-405-6206
steveb@keystonemasonryinc.com
2
Project Engineer’s Certification:
"I hereby state that this Construction SWPPP for the Wentworth Commercial Development has
been prepared by me or under my supervision and meets the standard of care and expertise which
is usual and customary in this community for professional engineers. I understand that the City of
Yelm does not and will not assume liability for the sufficiency, suitability, or performance of
drainage facilities prepared by me."
11/5/2022
3
Contents
Project Description .............................................................................................................................................. 4
Existing Site Conditions ...................................................................................................................................... 4
Soils ..................................................................................................................................................................... 4
Critical Areas ..................................................................................................................................................... 4
Existing Encumbrances .................................................................................................................................. 4
13 Elements of Construction Stormwater Pollution Prevention .............................................................. 4
Inspections ............................................................................................................................................................ 7
4
Project Description
The project proposes construction of a parking lot, sidewalk, and stormwater system for a
commercial development as depicted on the Stormwater Site Plan, Attachment A. The site is a
0.28-acre parcel. The project proposes 1,261 SF of new hard surface, and 14,562 SF of disturbed
area.
Existing Site Conditions
The site is generally rectangular in shape, with all onsite surfaces sloping down toward the
western corner of the site. The site functions as a pothole. Two building structures exist on the
site, with paved parking space for 1 or 2 vehicles. The total topographic relief across the site is
on the order of 2’ feet
Soils
The USDA Natural Resource Conservation Service (NRCS) Web Soil Survey maps the site as
being underlain by Spanaway gravelly sandy loam, 0 to 3 percent slopes (hydrologic soils group
A).
Critical Areas
No critical areas have been identified onsite.
Existing Encumbrances
There are no known existing encumbrances affecting the site.
13 Elements of Construction Stormwater Pollution Prevention
1. Preserve Vegetation/Mark Clearing Limits
a. Clearly mark limits of disturbance with high visibility flagging.
2. Establish Construction Access
a. Utilize only the existing paved driveway for construction access in accordance
with the Stormwater Site Plan.
b. If sediment is tracked off site, clean the affected roadway thoroughly at the end
of each day, or more frequently as necessary (for example during wet weather)
to prevent sediment from entering waters of the state. Remove sediment from
roads by shoveling or pickup sweeping and transport to a controlled sediment
disposal area. Street washing is allowed only after sediment is removed in this
manner.
3. Control Flow Rates
a. Ensure that runoff from all disturbed surfaces is directed only to the existing on-
site pothole, which is where all site runoff flows to in the existing condition. The
TESC plan assumes no offsite discharge.
4. Install Sediment Controls
a. Sediment controls will include inlet protection.
5. Stabilize Soils
a. Use mulch to stabilize all exposed and un-worked soils; protect the soil from the
erosive forces of raindrop impact, flowing water, and wind.
5
b. From October 1 through April 30, no soils shall remain exposed and un-worked
for more than 2 days. From May 1 to September 30, no soils shall remain
exposed and un-worked for more than 7 days. This condition applies to all soils
on site, whether at final grade or not.
c. Stabilize soils with mulch at the end of the shift before a holiday or weekend if
the weather forecast calls for precipitation.
d. Minimize the amount of soil exposed during construction activity.
e. Minimize soil compaction and, unless infeasible, preserve topsoil.
f. Permanently stabilize soils using the soil quality and depth BMP included in the
Stormwater Site Plan.
6. Protect Slopes
a. There are no proposed or existing slopes that require protection. No slopes
greater than 3:1 shall be created permanently or temporarily during
construction.
7. Protect Drain Inlets
a. Inlet protection shall be installed and maintained at the proposed Perk Filter
catch basin.
8. Stabilize Channels and Outlets
a. There are no proposed channels or outlets that require stabilization.
9. Control Pollutants
a. Handle and dispose all pollutants, including waste materials and demolition
debris that occur on-site, in a manner that does not cause contamination of
stormwater. Woody debris may be chipped, ground, or chopped and spread
on site.
b. Provide cover, containment, and protection from vandalism for all chemicals,
liquid products, petroleum products, and other materials that have the potential
to pose a threat to human health or the environment. On-site fueling tanks shall
include secondary containment. Secondary containment means placing tanks
or containers within an impervious structure capable of containing 110% of the
volume contained in the largest tank within the containment structure.
Doublewalled tanks do not require additional secondary containment.
c. Use spill prevention and control measures when conducting fueling,
maintenance and repair of heavy equipment and vehicles including oil changes,
hydraulic system drain down, solvent and de-greasing cleaning operations, fuel
tank drain down and removal, and other activities which may result in discharge
or spillage of pollutants to the ground or into stormwater runoff. Clean
contaminated surfaces immediately following any discharge or spill incident.
Emergency repairs may be performed on-site using temporary plastic placed
beneath and, if raining, over the vehicle.
d. Apply agricultural chemicals, including fertilizers and pesticides, in a manner and
at application rates that will not result in loss of chemical to stormwater runoff.
6
Follow manufacturers’ recommendations for application rates and procedures
shall be followed.
e. Washout of concrete trucks shall be performed off-site or in designated
concrete washout areas only. Do not wash out concrete trucks onto the ground,
or into storm drains, open ditches, streets, or streams. Do not dump excess
concrete on site, except in designated concrete washout areas. Concrete
spillage or concrete discharge to surface waters of the State if prohibited. Do
not use upland land applications for discharging wastewater from concrete
washout areas.
10. Control De-Watering
a. There are no proposed de-watering activities. If de-watering becomes
necessary, contact project engineer for direction prior to proceeding with de-
watering activities.
11. Maintain BMPs
a. Maintain and repair all temporary and permanent erosion and sediment control
BMPs as needed to assure continued performance of their intended function.
Conduct maintenance and repair in accordance with BMP specifications.
b. Remove all temporary erosion and sediment control BMPs not designed to
remain in place following construction within 30 days after final site stabilization
is achieved or after the temporary BMPs are no longer needed.
c. Permanently stabilize disturbed soil resulting from removal of BMPs or
vegetation. Protect all BMPs installed for the permanent control of stormwater
from sediment and compaction. All BMPs that are to remain in place following
completion of construction shall be examined and placed in full operating
condition. If sediment enters the BMPs during construction, it shall be removed
and the facility shall be returned to the conditions specified in the construction
documents.
12. Manage the Project Phasing of Construction
a. Phase development project and take into account seasonal work limits in order
to prevent soil erosion and, to reduce to the maximum extent practicable, the
transport of sediment from the site during construction.
b. All BMPs shall be inspected, maintained, and repaired as needed to assure
continued performance of their intended function. Site inspections shall be
conducted at least weekly and immediately following any substantial rainfall
event by a person who is knowledgeable in the principles and practices of
erosion and sediment control. The inspector must have the skills to assess the
site conditions and construction activities that could impact the quality of
stormwater, and assess the effectiveness of erosion and sediment control
measures used to control the quality of stormwater discharges.
c. The inspector must examine stormwater visually for the presence of suspended
sediment, turbidity, discoloration, and oil sheen. They must evaluate the
effectiveness of BMPs and determine if it is necessary to install, maintain, or
repair BMPs to improve the quality of stormwater discharges.
7
d. Implement appropriate BMPs or design changes as soon as possible whenever
inspection and/or monitoring reveals that the BMPs identified in the
Construction SWPPP are inadequate, due to the actual discharge of or potential
to discharge a significant amount of any pollutant.
e. Based on the results of the inspection, construction site operators must correct
the problems identified by:
i. Reviewing the SWPPP for compliance with the 13 construction SWPPP
elements and making appropriate revisions within 7 days of the
inspection.
ii. Immediately beginning the process of fully implementing and
maintaining appropriate source control and/or treatment BMPs as soon
as possible, addressing the problems no later than within 10 days of the
inspection. If installation of necessary treatment BMPs is not feasible
within 10 days, the construction site operator may request and
extension from the County within the initial 10-day response period.
iii. Documenting BMP implementation and maintenance in the site log book.
iv. The inspector must inspect all areas disturbed by construction activities,
all BMPs, and all stormwater discharge points at least once every
calendar week and within 24 hours of any discharge from the site. (For
purposes of this condition, individual discharge events that last more
than one day do not require daily inspections. For example, if a
stormwater pond discharges continuously over the course of a week,
only one inspection is required that week). The inspector may reduce
the inspection frequency for temporarily stabilized, inactive sites to once
every calendar month.
v. The Construction SWPPP shall be retained on-site or within reasonable
access to the site.
vi. The SWPPP shall be modified whenever there is a change in the design,
construction, operation, or maintenance at the construction site that
has, or could have, a significant effect on the discharge of pollutants to
waters of the state.
vii. The SWPPP shall be modified if, during inspections or investigations
conducted by the owner/operator, Pierce County or a state regulatory
authority, it is determined that the SWPPP is ineffective in eliminating or
significantly minimizing pollutants in stormwater discharges from the
site. The SWPPP shall be modified as necessary to include additional or
modified BMPs designed to correct problems identified. Revisions to the
SWPPP shall be completed within seven (7) days following the
inspection.
13. Protect Low Impact Development BMPs
a. There are no proposed LID BMPs
Inspections
8
As the project does not propose a discharge to waters of the state, site inspections shall be
conducted by a person who is knowledgeable in the principles and practices of erosion and
sediment control. Inspections shall conform to the guidelines provided under Element #12 above.
Attachment A
Stormwater Site Plan w/ SWPPP Elements
WWWWWWWWWWWWWWWWWWW W W W W W W W W W W W W W W W W W W W W W WCO
COPMTPMTCONC WALKEXISTINGBUILDINGEXISTINGGARAGECONC WALKGRAVELGRAVELGRAVELASPHALTDRIVECONCCONCBLOCKWALLCONCBLOCKWALLEXISTINGBUILDINGEDGE OF ASPHALTCURBEDGE OF ASPHALTEDGE OF ASPHALT
EDGE OF ASPHALTEDGE OF ASPHALTROOF PEAKEL==372.18'F.F.E.=353.29'EXISTINGSHED0.2'0.6'5.6'6.4'SSFILE NAME:Z:\P\JW301\CAD\Sheets\JW301 Final Plans.dwg DATE/TIME:12/22/2022 9:58:40 AM
DEMOLITION & TESC PLAN SEC19, TWN17, R2E WM
THURSTON CO TPN 75300900100
313 YELM AVE W
YELM, 98597
JENNIFER WENTWORTH
COMMERCIAL DEVELOPMENT
NDTRCB12-22-2022JW301NDTC339123456789101112131415ABCDEFGHIJ3 6 0 -8 9 0 -8 9 5 5 | 2 9 9 N M a r k e t B l v d , C h e h a l i s , W A 9 8 5 3 2DESIGNED BY:DRAWN BY:DATE:PROJ. NO:OFREVIEWED BY:Know what's BELOWCall 811 before you dig.NICH
O
L
ASDAVIDAYLORSTAT
E
OFWASHINGTONREGISTEREDPROFESSIONALENG
INEER T461131
2
-
2
2-2022 1234567KEY NOTES1.EXISTING ASPHALT CEMENT CONCRETE (ACC) DRIVEWAY. USE ASCONSTRUCTION ENTRANCE.2.DEMOLISH AND DISPOSE OF EXISTING PORTLAND CEMENT CONCRETE(PCC) SIDEWALK3.DEMOLISH AND DISPOSE OF EXISTING PCC SIDEWALK4.PROTECT EXISTING PCC SIDEWALK5.DEMOLISH AND DISPOSE OF EXISTING SIGN AND ASSOCIATEDCONCRETE BLOCKS6.PROTECT EXISTING TREE TO REMAIN (TYP)7.SAWCUT, REMOVE, AND DISPOSE OF EX. ASPHALT AS SHOWN.REMOVE EXISTING ROAD SECTION AS NEEDED TO ACCOMMODATENEW 4" DEPTH OF PAVEMENT. SEE RICE ST. SECTION DETAIL 3/C8.CONTRACTOR SHALL CONTACT THE GEOTECHNICAL ENGINEER ANDCITY PUBLIC WORKS INSPECTOR TO INSPECT EXISTING SUBGRADEPRIOR TO INSTALLATION OF THE ROADWAY SECTION. CONTRACTORSHALL PROVIDE A MIN. 48-HOUR NOTICE.(TYP)8.PROPOSED LIMITS OF DISTURBANCE9.PROTECT EXISTING WATER MAIN10.PROTECT EXISTING GAS LINE#SCALE IN FEET201008SW RICE ST
YELM AVE SEALLEY773910INSTALL AND MAINTAIN INLET PROTECTION SILT SOCK AT ALLPROPOSED CATCH BASINS.NOTES
Appendix G
Maintenance Com-
ponent Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Performed
Liner (if Applic-
able) Liner is visible and has more than three 1/4-inch holes in it. Liner repaired or replaced. Liner is fully covered.
Ponds Berms (Dikes)
Settlements
Any part of berm which has settled 4 inches lower than the design elevation
If settlement is apparent, measure berm to determine amount of settlement
Settling can be an indication of more severe problems with the berm or outlet works. A
licensed engineer in the state of Washington should be consulted to determine the source of
the settlement.
Dike is built back to the design elevation.
Piping
Discernable water flow through pond berm. Ongoing erosion with potential for erosion to con-
tinue.
(Recommend a Goethechnical engineer be called in to inspect and evaluate condition and
recommend repair of condition.
Piping eliminated. Erosion potential resolved.
Emergency Overflow/
Spillway and Berms
over 4 feet in height
Tree Growth
Tree growth on emergency spillways creates blockage problems and may cause failure of the
berm due to uncontrolled overtopping.
Tree growth on berms over 4 feet in height may lead to piping through the berm which could
lead to failure of the berm.
Trees should be removed. If root system is small (base less than 4 inches) the root system may be left in
place. Otherwise the roots should be removed and the berm restored. A licensed engineer in the state of
Washington should be consulted for proper berm/spillway restoration.
Piping
Discernable water flow through pond berm. Ongoing erosion with potential for erosion to con-
tinue.
(Recommend a Geotechnical engineer be called in to inspect and evaluate condition and
recommend repair of condition.
Piping eliminated. Erosion potential resolved.
Emergency Over-
flow/Spillway
Emergency Over-
flow/Spillway
Only one layer of rock exists above native soil in area five square feet or larger, or any expos-
ure of native soil at the top of out flow path of spillway.
(Rip-rap on inside slopes need not be replaced.)
Rocks and pad depth are restored to design standards.
Erosion See "Side Slopes of Pond"
Table V-A.1: Maintenance Standards - Detention Ponds (continued)
Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Per-
formed
General
Trash & Debris See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Poisonous/Noxious
Vegetation See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Contaminants and Pol-
lution See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Rodent Holes See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Storage Area Sediment Water ponding in infiltration pond after rainfall ceases and appropriate time allowed for infiltration. Treatment basins should infiltrate
Water Quality Design Storm Volume within 48 hours, and empty within 24 hours after cessation of most rain events.
Sediment is removed and/or facility is cleaned so
that infiltration system works according to design.
Table V-A.2: Maintenance Standards - Infiltration
2019 Stormwater Management Manual for Western Washington
Volume V -Appendix A -Page 1006
Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Per-
formed
(A percolation test pit or test of facility indicates facility is only working at 90% of its designed capabilities. Test every 2 to 5 years. If
two inches or more sediment is present, remove).
Filter Bags (if applicable)Filled with Sediment and
Debris Sediment and debris fill bag more than 1/2 full.Filter bag is replaced or system is redesigned.
Rock Filters Sediment and Debris By visual inspection, little or no water flows through filter during heavy rain storms.Gravel in rock filter is replaced.
Side Slopes of Pond Erosion See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Emergency Overflow Spillway
and Berms over 4 feet in height.
Tree Growth See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Piping See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Emergency Overflow Spillway
Rock Missing See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Erosion See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-
tion Ponds
Pre-settling Ponds and Vaults
Facility or sump filled
with Sediment and/or
debris
6" or designed sediment trap depth of sediment.Sediment is removed.
Table V-A.2: Maintenance Standards - Infiltration (continued)
Maintenance
Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Per-
formed
Storage Area
Plugged Air Vents One-half of the cross section of a vent is blocked at any point or the vent is damaged. Vents open and functioning.
Debris and Sediment
Accumulated sediment depth exceeds 10% of the diameter of the storage area for 1/2 length of storage vault or any point
depth exceeds 15% of diameter.
(Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2 length of
tank.)
All sediment and debris removed from storage
area.
Joints Between Tank/Pipe Section
Any openings or voids allowing material to be transported into facility.
(Will require engineering analysis to determine structural stability).
All joint between tank/pipe sections are sealed.
Tank Pipe Bent Out of Shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. (Review required by engineer to determine
structural stability).Tank/pipe repaired or replaced to design.
Vault Structure Includes Cracks in Wall, Bottom,
Damage to Frame and/or Top Slab
Cracks wider than 1/2-inch and any evidence of soil particles entering the structure through the cracks, or main-
tenance/inspection personnel determines that the vault is not structurally sound.
Cracks wider than 1/2-inch at the joint of any inlet/outlet pipe or any evidence of soil particles entering the vault through the
walls.
Vault replaced or repaired to design spe-
cifications and is structurally sound.
No cracks more than 1/4-inch wide at the joint of
the inlet/outlet pipe.
Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults)
2019 Stormwater Management Manual for Western Washington
Volume V -Appendix A -Page 1007
Maintenance
Component Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Per-
formed
Manhole
Cover Not in Place Cover is missing or only partially in place. Any open manhole requires maintenance.Manhole is closed.
Locking Mechanism Not Working Mechanism cannot be opened by one maintenance person with proper tools. Bolts into frame have less than 1/2 inch of
thread (may not apply to self-locking lids). Mechanism opens with proper tools.
Cover Difficult to Remove One maintenance person cannot remove lid after applying normal lifting pressure. Intent is to keep cover from sealing off
access to maintenance.
Cover can be removed and reinstalled by one
maintenance person.
Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, misalignment, not securely attached to structure wall, rust, or cracks.Ladder meets design standards. Allows main-
tenance person safe access.
Catch Basins See Table V-A.5: Maintenance Standards - Catch
Basins See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards -
Catch Basins
Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults) (continued)
Maintenance Com-
ponent Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed
General
Trash and Debris (Includes Sediment)Material exceeds 25% of sump depth or 1 foot below orifice plate.Control structure orifice is not blocked. All trash and debris removed.
Structural Damage
Structure is not securely attached to manhole wall.
Structure is not in upright position (allow up to 10% from plumb).
Connections to outlet pipe are not watertight and show signs of rust.
Any holes - other than designed holes - in the structure.
Structure securely attached to wall and outlet pipe.
Structure in correct position.
Connections to outlet pipe are water tight; structure repaired or replaced and
works as designed.
Structure has no holes other than designed holes.
Cleanout Gate Damaged or Missing
Cleanout gate is not watertight or is missing.
Gate cannot be moved up and down by one maintenance person.
Chain/rod leading to gate is missing or damaged.
Gate is rusted over 50% of its surface area.
Gate is watertight and works as designed.
Gate moves up and down easily and is watertight.
Chain is in place and works as designed.
Gate is repaired or replaced to meet design standards.
Orifice Plate
Damaged or Missing Control device is not working properly due to missing, out of place, or
bent orifice plate.Plate is in place and works as designed.
Obstructions Any trash, debris, sediment, or vegetation blocking the plate.Plate is free of all obstructions and works as designed.
Overflow Pipe Obstructions Any trash or debris blocking (or having the potential of blocking) the
overflow pipe.Pipe is free of all obstructions and works as designed.
Manhole See Table V-A.3: Maintenance Standards - Closed Detention Systems
(Tanks/Vaults)
See Table V-A.3: Maintenance Standards - Closed Detention Systems
(Tanks/Vaults)
See Table V-A.3: Maintenance Standards - Closed Detention Systems (Tank-
s/Vaults)
Catch Basin See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards - Catch Basins
Table V-A.4: Maintenance Standards - Control Structure/Flow Restrictor
2019 Stormwater Management Manual for Western Washington
Volume V -Appendix A -Page 1008
BAYSAVER TECHNOLOGIES, INC.
22
Maintenance of the
BayFilter™ System
The BayFilter™ system requires periodic maintenance to continue operating at the
design efficiency. The maintenance process comprises the removal and
replacement of each BayFilter™ cartridge and drain down module and the
cleaning of the vault or manhole with a vacuum truck. BayFilter™ maintenance
should be performed by a BaySaver Technologies, Inc. certified maintenance
contractor.
The maintenance cycle of the BayFilter™ system will be driven mostly by the
actual solids load on the filter. The system should be periodically monitored to be
certain it is operating correctly. Since stormwater solids loads can be variable, it is
possible that the maintenance cycle could be more or less than the projected
duration.
The BayFilter systems in New Development applications are designed to treat the
WQv in 24 hours initially. Later in the cycle these cartridges will flow at a slower
rate, and when the WQv does not drain down within +/- 40 hours after the storm
event, the system must be maintained.
When a BayFilter™ system is first installed, it is recommended that it be inspected
every six (6) months. When the filter system exhibits flows below design levels
the system should be maintained. Filter cartridge replacement should also be
considered when sediment levels are at or above the level of the 4 inch manifold
system. Please contact the BaySaver Technologies Inc. Engineering Department
for maintenance cycle estimations or assistance at 1.800.229.7283.
Chapter 4
BAYSAVER TECHNOLOGIES, INC.
23
Maintenance Procedures
1. Remove the manhole covers and open all access hatches.
2. Before entering the system make sure the air is safe per OSHA
Standards or use a breathing apparatus. Use low O2, high CO, or
other applicable warning devices per regulatory requirements.
3. Using a vacuum truck remove any liquid and sediments that can be
removed prior to entry.
4. Using a small lift or the boom of the vacuum truck, remove the
used cartridges by lifting them out.
5. Any cartridges that cannot be readily lifted directly out of the vault
should be removed from their location and carried to the lifting
point using the Trolley system installed in the Vault (if applicable).
6. When all cartridges and drain down modules are removed, remove
the balance of the solids and water; then loosen the stainless
clamps on the Fernco couplings in the pipe manifold; remove the
drain pipes as well. Carefully cap the manifold and the Fernco’s
and rinse the floor removing the balance of the collected solids.
7. Clean the manifold pipes, inspect, and reinstall.
8. Install the exchange cartridges and close all covers.
9. The used cartridges must be sent back to BaySaver Technologies,
Inc. for exchange/recycling and credit on undamaged units.