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Prelim Drain ReportYELM TOWN HOMESIGMS CONSTRUCTION YELM, WASHINGTON 27 a7 PRELIMINARY DRAINAGE REPORT KPFF Consulting Engineers 4200 Sixfh Avenue SE, Suite 309 Lacey, WA 98503 July 28, 2006 NF. ~~r~_ c PRELIMINARY DRAINAGE REPORT Yelm Town Homes/GMS Construction Yelm, Washington July 28, 2006 PROJECT INFORMATION Prepared for: GMS Construction Contact: Robert Sageman REVIEWING AGENCY Jurisdiction: City of Yelm, Washington Project Number: Project Contact: James Gibson, P.E. PROJECT ENGINEER Prepared by: KPFF Consulting Engineers 4200 6'" Avenue SE, Ste. 309 Lacey, WA 98503 Tel: (360) 292-7230 Fax: (360)292-7231 Contact: Clint Pierpoint, Civil Engineer KPFF Project: File Number: I:\2006\406029 GMS Town Homes\Project Documents\Pre Drainage Report GMS.doc PROJECT ENGINEERS CERTIFICATION: I hereby certify that this Preliminary Drainage Report and Erasion Control Plan for Yelm Townhomes in Yelm, Washington has been prepared by me or under my supervision and meets the minimum standards of the Ciry of Yelm and normal standards of engineering practice. I understand that the CITY does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me. Table of Contents PART I -DRAINAGE PLAN Section 1 - Proposed Protect Description......_ ...................._. .......... 1 Section 2 - Existing Covditions......._...._ ............................... .._...._ 4 Section 3 - Infiltration Rates/Soils Report_ .............._.._....... .......... 5 Section 9 ~ Wells and Septic SYStems ................................_.. ......._. 5 Section 5 - Fuel Tanks _ ................................_......._...._.._..... .......... 5 Section 6 - Sub-Basin Description ......................_.................. .......... 5 Section 7 - Analysis of the 100-Sear Flood..........._ ............... .......... 5 Section 8 - Aesthetic Considerations fur Facilities ................ _....__ 5 Section 9 ~ Facility Sizing and Downstream Analysis .......... .......... 6 Section 10- Covenants, Dedications and Easments .............. ......._. 6 Section 11 -Property Owners Association Articles Of Incorporeton6 PART II - EROSION CONTROL PLAN ........................... ...........7 Section 1 -Construction Sequence And Procedure ._ ................ ...... 7 Section 2 - TiaPPing Sediment ......................._..._..................... ...... 7 Section 3 -Permanent Erosion Control & Si[z Restoration.._._ _...7 Section 4 ~ Geotechnical Analysis And Report ......_ .................. ...._ 8 Section 5 - Inspection Sequence .................................................. ..... 8 Section 6 - Control Of Pollutants Other Thav Sediments .....__ .__ 8 PART III - iNAINTENANCE PLAN .................. 9 Section 1 -Required Maintenance .............................. .................__ 0 Section 2 - Responsible Organization..._ .................... ...._............. 18 Section 3 - Vegetation Management Ylan ._...._.___ _ ____.......... 18 Sectiou 4 - Source Cuntrol _ ...................................._.... .................. 18 APPENDICES Appendix 1 Storm Drainage Calculations Appendix 2 Drainage Plan Appendix3 FEMA Map Appendix 4 Facility Summary Forms Appendix 6 Soil Evaluation Report Appendix6 Maintenance Agreement Appendix 7 Vicinity Map ii Velm Town Homes Preliminary Drainage Report Part I Drainage Plan Yelm Town Homes Preliminary Drainage Report PART I -DRAINAGE PLAN SECTION 1 -PROPOSED PROJECT DESCRIPTION Parcel Number: Total Site Area: Address: Zoned: Required Permits: Section, Township, Range: 21724410200 1.0 acres 304 Longmire Street East Yelm, WA 98597 R-14 Building, Grading, Paving, etc. Section 24, Township 17 North, Range i East, W.M., Thurston County, WA Site Location The project site is located in Yelm, Washington southeast of the intersection of Longmire Street SE and Berry Valley Road SE in Thurston County, Washington. Access to the site is from Longmire Street SE. Project Overview The applicant is proposing to construct 15 town home units on the 1.0-acre site. Each unit has a building footprint of approximately 750 square-feet. The site will be constructed in one phase and will include appropriate erosion control measures as needed, grading, storm drainage improvements, frontage improvements and connection to existing underground utilities including water and sanitary sewer. Storm Drainage Improvements: The total site area is 1.0 Acre. The existing site is partially developed with an abandoned single-family residence located on the north corner of the property. The post development drainage basin breakdown of the site is as follows: • 0.24 acres of impervious driveways • 0.30 acres of roof area 0.46 acres of disturbed pervious area (planter strips/landscaping) Stormwater Treatment/Infiltration: Stormwater treatment requirements are based on the 1992 edition of the WSDOE Stormwater Management Manual StormShed Software was used to size the treatment facilities. Preliminary treatment calculations are provided in Appendix I. The Basin: KPFF Consul July 28, 2006 Yelm Town Homes Preliminary Drainage Report Runoff will sheet Flow towards the northwest property line where it will enter a biofiltration Swale that will treat the 6-month/24-hour event as the Manual requires and carry runoff to an infiltration trench for infiltration to groundwater. All runoff will be contained on-site. The infiltration trench was sized to accommodate the 100-year/24-hour event. WSDOE Stormwater Management Manual requires infiltration trenches to be able to infiltrate 100% of 100-year/24-hour storms within 48 hours. SECTION 2 -EXISTING CONDITIONS The project site is bounded on the northeast and southeast by existing residential property. Longmire Street SE forms the northwest site boundary and an existing golf course bounds the property to the southwest. An abandoned single-family residence approximately 780 square feet in area is located in the north corner of the property. Site relief is gently sloping from the southwest to the northeast. Elevations range from a high of 348 ft. at the southwest corner to a low of 341 ft. at the northeast property line. The site is covered with grass, shrubs and a few trees. On-site soils are typically recessional glacial outwash. Soil tests indicate some locations have existing fill material extending to depths of 2 % feet below existing ground surface. There are no creeks, lakes, ponds, springs, wetlands, ravines, gullies, steep slopes or other environmentally sensitive areas identified onsite or down gradient of the subject property. SECTION 3 -INFILTRATION RATES/SOILS REPORT The Geologic Map of Thurston County, Washington, East Half (Plate 2)(Noble 1960- 62) indicates the site is underlain by Vashon glacial recessional outwash(Ovr). Material was deposited as the Vashon Glacier receded. Onsite soil test pits examined confirm this classification. A geotechnical assessment of the site was performed by GeoEngineers in April of 2006 and is attached in appendix 5. The recommendation of the soils professionals is to use a design infiltration rate of 20 inches per hour. SECTION 4 -WELLS AND SEPTIC SYSTEMS The site was served by a single well and a single septic system. The well and septic system will be abandoned and removed in accordance with WA DOE and Thurston County Department of Health rules and regulations. SECTION 5 -FUEL TANKS A review of the DOE'S Leaking Underground Storage Tanks (LUST) list did not indicate the presence of any existing or abandoned fuel tanks on or near the project site. SECTION 6 -SUB-BASIN DESCRIPTION The project site is located within the Nisqually River Watershed per the Thurston County GeoData Center. There is no significant off-site runoff to the project site. The proposed development is being treated as a single drainage basin for the purpose of this study. The facilities proposed for this basin consist of a biofiltration Swale to provide Stormwater treatment and an infiltration trench to provide storage and KPFF Consulting July 28, 2006 Yelm Town Homes Preliminary Drainage Report infiltration to the groundwater. No handling of hazardous materials on this site is anticipated. SECTION 7 -ANALYSIS OF THE 100-YEAR FLOOD The site is found in FEMA FIRM panel 5303100001A, all of the subject property is in zone X. This is an area determined to be outside of the 500-year Flood plain. This project does not contain a stream onsite. A FEMA FIRM map is included in Appendix 3. SECTION 8 -AESTHETIC CONSIDERATIONS FOR FACILITIES All disturbed pervious areas will be vegetated and landscaped during construction. A landscape plan will be submitted and approved prior to construction. Underground storage will occur with the infiltration trench and therefore fences will not be an issue. SECTION 9 -FACILITY SIZING AND DOWNSTREAM ANALYSIS Detailed storm drainage calculations are included in Appendix 1 of this report. All on- site stormwater runoff will be treated, stored, and infiltrated on-site. Calculations for sizing of facilities are included in Appendix 1. Since all stormwater will be infiltrated onsite, a downstream analysis was deemed unnecessary. SECTION 10 -COVENANTS, DEDICATIONS AND EASEMENTS Drainage facilities including the infiltration trench and bio-infiltration swales will require routine maintenance. The maintenance manual prepared for the project lists the maintenance requirements. See Part III -Maintenance Plan of this report. SECTION 11 -PROPERTY OWNERS ASSOCIATION ARTICLES OF INCORPORATION In light of the residential nature of this project, special covenants covering landscape, maintenance, signage, stormwater, and site maintenance may be put in place at the time of final platting. The Home Owners Association and/or their representatives will pertorm maintenance of these private storm drainage facilities. KPFF Consulting Engineers July 28, 2006 Yelm Town Homes Preliminary Drainage Report Part II Erosion Control Plan Yelm Town Homes Preliminary Drainage Report PART II -EROSION CONTROL PLAN SECTION 1 -CONSTRUCTION SEQUENCE AND PROCEDURE The proposed project will include an erosion control plan designed to contain silt and soil within the project boundaries during construction until permanent vegetation and site improvements are in place. Erosion/sedimentation control will be achieved by a combination of structural/vegetation cover measures and construction practices tailored to fit the site. Best Construction Management Practices (BMP's) will be employed to properly clear and grade the site and to schedule construction activities. Before any construction begins on-site, erosion control facilities shall first be installed. The planned construction sequence is as follows: 1. Install rock construction entrances. Use 4" to 8" diameter spalls with 12" minimum depth. 2. Install filter fabric fencing and construction fence where appropriate and as shown on the plans. 3. Clear site (grubbing and rough grading). 4. Designate an area for washing of equipment and concrete trucks to control the runoff and eliminate entry into the storm drainage systems 5. During November 1 through March 31, all disturbed areas greater than 5,000 sf that are to be left unworked for more than twelve (12) hours shall be stabilized by one of the following: mulch, sodding or plastic covering. 6. Provide catch basin inlet protection by installing silt socks under grates of all inlets to drainage system. 7. Install utilities (water, sanitary sewer, power, etc.). 8. Install pervious concrete, curbing, sidewalks, etc. 9. Landscape and/or seed all disturbed areas. 10. Maintain all erosion control facilities until the entire site is stabilized and silt runoff ceases. 11. After the site has been stabilized the infiltration trench will be restored to designed conditions. SECTION 2 -TRAPPING SEDIMENT Filter fabric fencing will be installed wherever runoff has the potential to impact downstream resources. This shall include the areas along downstream property lines. During construction, the Contractor will also be required to install f lter fabric fencing as needed, and as directed by the Engineer and/or the City of Yelm. Catch basin protection shall be provided by installing silt socks under grates of all inlets to drainage system. Stabilized construction entrances will be installed to prevent vehicles from tracking soil away from the site. If sediment is tracked off-site, it shall be swept or shoveled from paved surfaces on a daily basis, so that it is not washed into existing catch basins or other storm drainage facilities. All disturbed/exposed soils shall be covered with straw or mulch to prevent erosion in these areas. The Contractor will not be allowed to leave disturbed areas greater than 5,000 sf (that are to be left unworked for more than twelve (12) hours) uncovered during the rainy season from November 1 through March 31. Mulch, sodding or plastic covering will be used to prevent erosion in these areas. KPFF Consulting Engineers July 26, 2006 Velm Town Homes Preliminary Drainage Report SECTION 3 -PERMANENT EROSION CONTROL & SITE RESTORATION All disturbed areas will be paved, covered with a building, or landscaped with grass, shrubbery or trees per the development plans. SECTION 4 - GEOTECHNICAL ANALYSIS AND REPORT See Appendix 5 for a complete geotechnical soils report. There are no slopes exceeding 15- percent, therefore a geotechnical report for slope analysis was deemed unnecessary. SECTION 5 -INSPECTION SEQUENCE In addition to City inspections, the Project Engineer shall inspect the facilities related to stormwater treatment, erosion control, storage and conveyance during construction. At a minimum, the following items shall be inspected at the time specified: 1. The erosion control facilities should be inspected before the start of clearing and grading to ensure the following structures are in place: a. Construction Entrance b. Filter Fabric Fences c. Catch Basin Inlet Protection 2. The conveyance systems will be inspected after construction of the facilities, but before project completion to ensure the following items are in working order: a. Pavement Drainage b. Catch Basins c. Conveyance Piping d. Roof Drain Piping 3. The erosion control and conveyance items listed above shall be inspected as soon as practical following every significant rainfall event (2-inches in a 24-hour period) that occurs during construction. 4. The permanent site restoration measures shall be inspected after landscaping is completed 5. A foal inspection will be performed to check final grades, settings of control structures and all necessary findings to complete the Engineer's Construction Inspection Report Form. This form must be completed prior to final public works construction approval. SECTION 6 -CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS Washout from concrete trucks shall not be dumped into the storm drain, or onto soil and pavement, which carries stormwater runoff. It shall be dumped into a designated area to be later backfilled or hardened and broken up for disposal into a dumpster. The Contractor is required to designate a washdown area for equipment and concrete trucks. KPFF Consulting Engineers July 28, 2006 Yelm Town Homes Preliminary Drainage Report Part III Maintenance Plan Yelm Town Homes Preliminary Drainage Report PART III -MAINTENANCE PLAN SECTION 1 - REQUIRED MAINTENANCE The on-site storm drainage facilities will require occasional maintenance. The following is based on minimum requirements as set forth in the Drainage Design and Erosion Control Manual of Thurston County. The required maintenance and frequency of maintenance are as follows: The following pages contain maintenance needs for most components that are part of the drainage system, as well as for some components that are not. Ignore the requirements that do not apply to this system. A checklist should be completed for all system components according to the following schedule: 1. Monthly from November through April. 2. Once in late summer (preferably September). 3. After any major storm (use 1" in 24 hours as a guideline), items marked "S" only. Using photocopies of these pages, check off the problems identified with each inspection. Add comments on problems found and actions taken. Keep these "Checked" sheets in a file, as they will be used to write the annual report (due in May of each year). Some items do not need to be looked at every time an inspection is done. Use the suggested frequency at the left of each item as a guideline for the inspections. The City of Yelm is available for technical assistance. Do not hesitate to call, especially if it appears that a problem may exist. KPFF Consulting Engineers July 28, 2006 Yelm Town Homes Preliminary Drainage Report ATTACHMENT "A": MAINTENANCE PROGRAM COVER SHEET Inspection Period: Number of Sheets Attached: Date Inspected: Name of Inspector: Inspector's Signature: KPFF Consul' Jury 28, 2006 Yelm Town Homes Preliminary Drainage Report ATTACHMENT "A" Maintenance Checklist for Conveyance Systems (Pipes and Swales) Frequenc Drainage Req Problem Conditions to Check For Conditions That y System d Should Exist Feature M.S. Pipes ~ Sediment Accumulated sediment Pipe cleaned of all & debris that exceeds 20% of the sediment and debris. diameter of the i e. M ~ Vegetation Vegetation that reduces All vegetation free movement of water removed so water throu h i es. flows freel . A ~ Damaged Protective coating ie Pipe repaired or (rusted, damaged; rust is replaced. bent or causing more than 50% crushed) deterioration to any part of i e. M ~ Any dent that Pipe repaired or significantly impedes replaced. flow (i.e., decreases the cross section area of pipe b more then 20% . M ~ Pipe has major cracks or Pipe repaired or tears allowing replaced. oundwater leaks e. M.S. Swales ~ Trash & Dumping of yard wastes Remove trash and debris such as grass clippings debris and dispose as and branches into Swale. prescribed by County Unsightly accumulation Waste Management of non-degradable Section. materials such as glass, plastic, metal, foam and coated a er. M ~ Sediment Accumulated sediment Swale cleaned of all buildup that exceeds 20 % of the sediment and debris design depth. so thatit matches design. M ~ Vegetation Grass cover is sparse Aerate soils and not and weedy or areas are reseed and mulch growing or overgrown with woody bare areas. Maintain overgrown vegetation, grass height at a minimum of 6" for best stormwater treatment. Remove woody growth, recontour and reseed as necessar -. M,S ~ Erosion Sec ponds checklist See ponds checklist damage to slo es KPFF Consulting Engineers 6 July 28, 2006 Yelm Town Homes Preliminary Drainage Report M ~ Conversio Swale has been filled in If possible, speak n by home or blocked by shed, with DEVELOP woodpile, shrubbery, etc. hameDEVELOPER ER to and request that incompatib swats area be le use restored. Contact City to report problem if nat rectified voluntaril . A ~ Swale does Water stands in swats A survey maybe not drain or flow velocity is very needed to check slow. Stagnation occurs. grades. Grades need to be in 1 % range if possible. If grade is less than 1%, underdrains may need to be installed. If you ere unsure whether a problem exists, please contact the CIq'P and ask for technical assistance. Comments: Key: A =Annual (March or April preferred) M =Monthly (see schedule) Q =Quarterly S =After major storms KPFF Consulting Engineers g July 28, 2006 Yelm Town Homes Preliminary Drainage Report ATTACHMENT "A" Maintenance Checklist for Catch Basins and Inlets Feature Drainage Problem Conditions to Check Conditions That System Req'd For Should Exist Feature M.S. General Trash, debris Trash or debris in front No trash or debris and sediment of the catch basin located immediately in or on basin opening is blocking in front of catch basin capacity by more than opening. Grate is 10%. kept clean and allows water to enter. M Sediment or debris (in No sediment or debris the basin) that exceeds in the catch basin. 1B the depth from the Catch basin is dug bottom of basin to out and clean. invert of the lowest pipe into or out of the basin. MS. Trash or debris in any Inlet and outlet pipes inlet or pipe blocking free of trash or more than 1/3 of it's debris. hei ht. M Structural Corner of frame Frame is even with damage to extends more than 3/4" curb. frame and/or past curb Face into the top slab street (if applicable). M Top slab has holes Top slab ie free of larger than 2 inches or holes and cracks. cracks wider than 1/4" (intent is to make sure all material is running into the basin . M Frame not sitting flush Frame is sitting flush on top Blab, i.e., on top slab. separation of more than 3/4" of the frame from the to elab. A Cracks in Cracks wider than 1/2" Basin replaced or basin and longer than 3', any repaired to deeign walls bottom evidence of sail standards. Contact a particles entering catch professional engineer basin through cracks or for evaluation. maintenance person judges that structure ie unsound. A V Cracks wider than 1/2" No cracks more than and longer than 1' at 1/4" wide at the joint the joint of any of inleUoutlet pipe. inleUoutlet pipe or any evidence of eoiL particlee entering catch basin throw h cracks. ...y o~yu~ e~~ 10 Jury 28, 2006 Yelm Town Homes Preliminary Drainage Report 9 SettlementJm is-alignment Basin has settled more than 1" or hoe rotated more than 2" out of alignment. Basin replaced ox repaired to design standards. Contact a professional engineer for evaluation. M.S. Fire hazard Presence of chemicals No color, odor or or other such as natural gas, oil sludge. Basin is dug pollution and gasoline. out and clean. Obnoxious color, odor or slud e noted. M.S. Outlet pipe ie Vegetation or roots No vegetation or root clogged with growing in inletAoutlet growth present. vegetation pipe joints that ie more than 6" tall and less than 6" apart. If you are unsure whether a problem exists, please wntact the CI1'P and ask £or technical assistance. Comments: Key: A =Annual (March or April preferred) M = Monthly (see schedule) Q =Quarterly S =After major storms KPFF Consulting Engineers July 28, 2006 Velm Town Homes Preliminary Drainage RepoA ATTACHMENT "A" Maintenance Checklist for Grounds (Landscaping) Frequency Drainag Req'd Problem Conditions to Check Conditions That Should e System For Exist Feature M General Weeds Weeds growing in Weeds present in lees (nonpoisonous) mare than 20% of the than 6 % of the landscaped area (trees landscaped area. and shrubs onl ). M J Safety Lazard Any presence of No poisonous vegetation poison ivy or other or insect Heats present in poisonous vegetation landscaped area. or insect nests. M.S. Trash & debris Dumping of yard Remove trash and debris buildup in wastes such as grass and dispose as open space clippings and prescribed by City Waste branches. Unsightly Management SecEion. accumulation of non- degradable materials such as glass, plastic, metal, foam and coated a er. M Missing or Any defect in the Fence is mended or broken fence or screen that shrubs replaced to form parts/dead permits easy entry to a solid barrier to entry. shrubbery a £acilitu. M.S. Erosion Erosion has resulted Replace soil under fence in an opening under a so that no opening fence that allows exceeds 4" in height. entry by people or Cauees of erosion pets. identiSed and steps taken to slow down and/or spread out the water. Eroded areas are filled, contoured, and seeded. M Unruly Shrubbery is growing Shrubbery is trimmed vegetation out of control or ie and weeded to provide infested with weeds. appealing aesthetics. Do not use chemicals to control weeds. A Trees J Damage Limbs or parts of Trim trees/shrubs to and trees or shrubs that restore shape. Replace shrubs are split or broken trees shrubs with severe which affect more damage. than 25% of the total foliage of the tree or shrub. M J Trees or shrubs that Replant tree, inspecting have been blown down for injury to stem or or knocked over. roots. Replace i£ severely damaged. KPFF Consulting Engineers July 28, 2006 Yelm Town Homes Preliminary Dreinage RepoA A Trees or shrubs which Place stakes and rubber- are not adequately coated ties around young supported or are treeslshrubs £or support. Leaning over, causing _ _ _ exposure of the roots. If you are unsure whether a problem exists, please contact the CITY and ask for technical assistance. Comments: Key: A =Annual (March or Apri] preferred) M =Monthly (see schedule) Q =Quarterly S =After major storms KPFF Consul' July 28, 200fi Yelm Town Homes Preliminary Drainage Repoli ATTACHMENT "A" Maintenance Checklist for Infiltration Systems Freque Drainage Req'd Problem Conditions to Check For Conditions That Should ncy System Exist Feature M,S General ~ Trash & Clumping of yard wastes Removed trash and debris such as grass clippings debris and dispose as and branches into basin. prescribed by City Unsightly awumulation Watte Management of no degradable Section materials such as glass, plastic, metal, foam and coated a er. M ~ Poisonous Any poisonous Remove poisonous vegetation vegetation, which may vegetation. Do not constitute a hazard to spray chemicals on the public. Examples of vegetation without poisonous vegetation obtaining guidance include: tansy ragwort, from the Cooperative poison oak, stinging Extension Service and nettles, and devilsclub. a royal from the City. M,S ~ Fire hazard Presence of chemicals Find sources of or pollution such as natural gas, oi] pollution and eliminate and gasoline, obnoxious them. Water is free color, odor or sludge from noticeable color, noted. odor or contamination. M Rodent Any evidence o£rodent Rodents destroyed and holes holes if facility is acting dam or berm repaired. as a dam or berm, or any Contact the Thurston evidence of water piping County Health through dam or berm via Department for rodent holes. uidance. M d Insects When insects such as Insects destroyed or wasps and hornets removed from site. interfere with Contact Cooperative maintenance activities, Extension Service for or when mosquitoes guidance. become a nuisance. A d Tree growth Tree growth does not Trees do not hinder allow maintenance maintenance activities. access or interferes with Selectively cultivate maintenance activity trees such as alders for (i.e., slope mowing, silt firewood. removal, or equipment movements). If trees are not interfering with access, leave trees alon . KPFF Consulting Engineers tq July 28, 2006 Yelm Town Homes Preliminary Drainage Report A Storage ~ Sediment A soIl texture test Sediment is removed area buildup in indicates facility is not and/or facility is 'i system working at its designed cleaned so that capabilities or was infiltration system incorrectly designed. works according to design. A sediment trapping area is installed to reduce sediment transport into infiltration area. A d Storage A soil texture test Additional volume is area drains indicates facility is not added through slowly working at its designed excavation to provide (more than capabilities or was needed storage. Soil is 48 hours) ox incorrectly designed. aerated and rototilled to overflows improve drainage. Contact the City for information on its requirements regarding excavation. M d Sediment Any sediment and debris Clean out sump to trapping filling area to 10% of design depth. area depth from sump bottom to bottom of outlet pipe or obstructing flow into the connector i e One ~ Sediment Stormwater enters Add a trapping area by Time trapping infiltration area directly constructing a sump far area not without treatment settling of solids i present Segzegate settling area from rest of facility. Contact City for uidance. M Rock Sediment By visual inspection Replace gravel in rock Filters and debris little or no water flows filter. through filter during hea rainstorms. S Infiltration ~ Infiltratim ___ Standing water in Excavate bottom o£ Trenches failure inpection well after 48 trench as necessary but hours after storm or at least 3 feet. Replace overflow during storms. with crushed rock. Check pretreatment system For effectiveness. Check tributary area for sediment sources. If you are unsure whether a problem exists, please contact the Jurisdiction and ask for technical assistance. Comments: Key: A =Annual (March or April preferred) M =Monthly (see schedule) S = After major storms uny oiyineers 15 Juy 28, 2006 Velm Town Homes Preliminary D2inage RepoM1 SECTION 2 -RESPONSIBLE ORGANIZATION The Home Owners Association shall be responsible for the operations and maintenance of all onsite storm drainage facilities. SECTION 3 -VEGETATION MANAGEMENT PLAN All disturbed pervious areas on the site will be landscaped to provide an aesthetically pleasing environment. SECTION 4 -SOURCE CONTROL Warning Signs (e.g. "Dump No Waste -Drains to Groundwater") will be embossed or painted on or adjacent to all storm drain inlets and will be repainted periodically as necessary. July 28, 2006 ,..y ~..y.~.~~~ ~ i 6 Yelm Town Homes Preliminary Drainage Report Appendix 1 Storm Drainage Calculations Yelm Town Homes Preliminary Drainage Repon PRELIMINARY DRAINAGE CALCULATIONS The following calculations are based on the requirements contained in the 1992 Washington State Department o£Ecology (WSDOE) Stormwater Management Manual for the Puget Sound Basin. DESIGN AND BASIN INFORMATION SUMMARY Soil Classification SCS Soil Classification: Spanaway (110) (Vashon glacial recessional outwaeh (Qvr)) Hydrologic Group B Infiltration Rate 20 inches/hour SCS Runoff Curve Number (Table III-1.3 WSDOE Storm Manua)) Post-developed (Lawns, 75%+grass caver)~ CN=80 Poet developed (impervious, xoofe, pavement) CN=98 Rainfall Design Stnrme~ (WSDOE Isopluvial Maps-App. AIIh1.1 of WSDOE Storm ManuaU 6-month storm (64 % of 2 yr. Storm) =1.28" 2 yr.124 hour storm =2.0" 10 yr./24 hour storm =3.1Y' 100 yr.124 hour storm =4.0" Poat-Developed Basin Area Summary Tributary Lot Impervious Area (PavemenUsidewalk) 0.24 Ac Disturbed Pervious and Undisturbed Pervious ( ass/landsca in ) 0.46 Ac Nan-tributary impervious Area (root) 0.30 Ac Total 1.00 Ac DETAILED CALCULATIONS Stormwater Treatment Stormwater runoff will be routed through a bioSltration Swale to provide runoff treatment as it proceeds to an infiltration trench with capacity to infiltrate the design storm event. StormShed software was used to model the runoff. Sizing Calculations See the following StormShed software modeling peak output for the design storm event: Desi n Storm 24 hour Peak Out ut O 6-month 0.153 cfs D 2 r. 0.308 cfs O 10 r. 0.540 cfs ' O 100 r. 0.778 cfs Yelm Town Homes Preliminary Drainage Report Biofiltration Swale The biofiltration Swale was sized as both a treatment facility and as a conveyance system to pass the 10 and 100-yeaz design storms to the infiltration trench. Using StormShed software the biofiltration Swale was designed to conform to WSDOE Stormwater Manual criteria. Biofiltration swale(treatment)~ Q(6 month)=0.153 cfe Longitudinal slope = 2% Assume 6" approved grass species height (n=0.07) Trapezoidal shape with 3~1 side slopes Swale length = 100 ]f Required bottom width = 0.61' Designed bottom width = 3.00' Deeign flaw depth for Q(6 month) = O.OS5' (1") Design flow velocity for Q(6 month) = 0.65 fps (< 1.6 fps, ok) Biofiltration swale(Stability check) Q(100 yrJ =0.778 cfs Longitudinal slope = 2 Assume 6" approved grass species height (n=0.07) Trapezoidal shape with 3.0' bottom width and 3~1 aide slope Design flow depth for Q(100 yr.)=0.219' (2.6") Design flow velocity for Q(100 yr) = 0.97 fps (below erosive velocities of all approved species, per table III-6.3 of WSDOE Storm Manuall Bicfiltxation Swale is designed with LO' of freeboazd- Design depth is 1.26-feet Infiltration Trench The 1992 edition of the WSDOE Stormwater Management Manual was used to size the infiltration trench. The manual requires the 100-year/24-hour storm event to infiltrate 100% within 48 hours. The calculations were based on the infiltration rate of 20- inches/hour suggested by soil professionals after investigation of the site. The Darcy's Law approach is used to demonstrate sufficient capacity of the infiltration trench. Q=f *i`A, where Q= flowrate at which runoff ie infiltrated/filtrated by infiltration trench f= infiltration rate of soil or infiltration media i= hydraulic gradient A= surface area of BMP A factor of safety of "two" was applied to the recommended design infiltration rate of 20 in/hr, thus f=20 in/hr * 0.5 = 10 in/hr = 0.83 ft/hr Yelm Town Homes Preliminary Drainage Report The hydraulic gradient is shown by the equation i=(h+L)/L where h is the height of the water column over the infiltration/filtration media and L is the distance from the top surface of the BMP to the water table or impermeable layer. For design purposes hydraulic gradient i was set equal to 1, which made diechazge independent of stage. L = aseume 10 feet According to StormShed the 100-year/24-hour storm event will result in peak volume of 926 ef. Assumed bottom of trench elevation of 100'. Design void % £or drain rock is 30%. Accounting for 12" perforated pipe total void %=32.7%. Ueing a 4'W A 6'D X146'L Infiltration trench At base elevation 100' A=680 s£ Q(a) _ (0.83 * (0+10)/10) * 680 = 481 cf/hr Conservatively assuming infiltration rate by bottom area only, 481 cf/hr *48 hrs = 23,088 cf. Thus the infiltration trench will have the capacity to infiltrate 23,088 of per 48-hour period, which exceeds the 100-year/24-hour event volume of 926 cF. In the case of an event larger than the 24-hour/100-year storm excessive runoff will back up into the drainage awale and flow to the natural low point near the northeast property line. Page 1 of 3 Appended on: 16:12:19 Thursday, July 06, 2006 LPOOLCOMPUTE [trench] SUMMARY using Puls Start of live stora e: 100.0000 ft Event Match Q (efs) Peak Q (cfs) Peak Stg (ff) Vol (cf) Vol (acft) Time to Empty 6 month 0.1526 0.1426 100.1216 23.06 0.0005 24.67 2 yeaz 0.3082 0.2065 101.0472 198.61 0.0046 24.83 100 yeaz 0.7779 0.4711 104.8831 926.13 0.0213 24.83 Running C:\\Documents and Settings\\BenE\\My Documents\\trench Repor[.pgm on Thursday, July 06,2006 Summary Report of all Detention Pond Data Event Precip (in) 6 month 1.2800 2 year 2.0000 ] 0 year 3.0000 100 yeaz 4.0000 BASLIST2 [developed] Using [TYPEIA] As [6 month] [developed] Using [TYPE]A] As [6 month] [developed] Using [TYPEIA] As [2 year] [developed] Using [TYPEi A] As [2 yeaz] [developed] Using [TYPEIA] As [100 yeaz] [developed] Using [TYPEIA] As [100 yeaz] LSTEND BasinID Event Peak Q (cfs) Peak T (hrs) Peak Vol (ac-cf) Area (ac) Method/Loss Raintype developed 6month 0.1526 8.00 0.0573 1.00 SBUH/SCS TYPEIA developed 6month 0.1526 8.00 0.0573 1.00 SBUH/SCS TYPEIA develo ed 2 yeaz 0.3082 8.00 0.1091 1.00 SBUH/SCS TYPEIA developed 2yeaz 0.3082 8.00 0.1091 1.00 SBUH/SCS TYPEIA developed 100 yeaz 0.7779 8.00 0.2657 1.00 SBUH/SCS TYPEIA developed 100 year 0.7779 8.00 0.2657 1.00 SBUH/SCS TYPEIA BASLIST [TYPEIA] AS [6 month] DETAILED [developed] LSTEND Record Id: developed file://C:\Documents and Settings\BenE\My Documents\scratch pond.html 7/6/2006 Page 2 of 3 (Design Method SBUH Rainfall type TYPEIA Hyd Inri 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 Pervious Area (AMC 2) 0.70 ac DCIA 0.30 ac Pervious CN 90.23 DC CN 98.00 Pervious TC 7.81 min DC TC 5.79 min Pervious CN Calc Description SubArea Sub cn Open spaces, ]awns,parks (>75% grass) 0.46 ac 80.00 Impervious surfaces (pavements, roofs, etc) 0.24 ac 98.00 Pervious Composited CN (AMC 2) 86.17 Pervious TC Calc Type Description Length Slope Coeff Misc TT Sheet Short prairie grass and lawns.: 0.15 40.00 ft 1.00% 0.1500 2.50 in 7.03 min Shallow Paved 150.00 fr 2.50% 0.0100 0.78 min Pervious TC 7.81 min Directly Connected CN Calc Description SubArea Sub cn Impervious surfaces (pavements, roofs, etc) 0.30 ac 98.00 DC Composited CN (AMC 2) 98.00 Directly Connected TC Calc Type Description Length Slape Coeff Misc TT Shallow Paved 150.00 ft 2.40% 0.0100 0.79 min Fixed Tt fixed 5.00 min Directly Connected TC 5.79min HYDLIST SUMMARY [6 month out] [2 year out] [100 year out] LSTEND HydID Peak Q (cfs) Peak T (hrs) Peak Vol (soft) Cont Area (ac) 6 month out 0.1426 8.00 0.0573 1.0000 2 year out 0.2065 8.33 0.1091 1.0000 100 year out 0.4711 8.33 0.2657 1.0000 STORLIST [trench out] LSTEND file://C:\Documents and Settings\BenE\My Documents\scmtch pond.html 7/6/2006 Page 3 of 3 Record Id: trench out Descrip: infiltration trench Increment 0.10 ft Start El. 100.0000 fr Max EI. 105.0000 ft Length 145.0000 fr Width 4.0000 ft Catch 32.7000 DISCHLIST [i~ltration] LSTEND Record Id: infiltration Descrip: infiltration rate Increment 0.10 ft Start EI. 100.0000 ft Max El. 105.0000 ft Infiltration rate 10.0000 in/hr WP Multiplier 1.00 Licensed to: KPFF, Inc. -Olympia file://C:\Documents and Settings\BenE\My Documents\scratch pond.html 7/6/2006 Appendix 2 Drainage Plan wl Ni ~,° I ~ J36.. r i ~~ ~~ -= a z II dz '~ d i -~,~- _ _ - - ~° za 1~ ~_- - T it McKENZIE AVE ~ _ ~ w fiY~ w ~, d U' --_. - __- », _ ~3 ~ d -. ~I-.. _.__ 31e _ __. =s U' Z 'I __ _- _ f ~ > p m O d ~ ~ ~ U` I J I } I i ~OO~d / 'k 0 ~ ~ wEUw O O O~~ _s_ ao s ~, i ~ ~ wam. 0 I ~ „a - z ~~ ~~°-.~ I o~ z° w m_N „ o °sd ~I M 1 ~ ~~ x - i i ~ a9J ~ 100 0 ~- "~~~ ~ ~~ ~~ 6 ~~ 1 I 3 ~ ' 1 o~j ~ 4d.0 I _ _ ~ I 28 0 4 IN ~ rv~ n.5 >:0 i 0 1 _ 15.0 ' Ili n a _x ~ I ~' i ~i ... I 4` k e I. ,~ w ~ 24 5 i. y ~w ~ ~ ~ ~ ~ } F ~ ~ _ ~ ~' ~ }IR V ~,I ~aoi Ito ~~ -ro ~~o ~ ~~ t ~ ~ ,5 __ ,a o 4 (7 ~ „. ~ 8 a's paJ ~ ~ S'+ _ - = Ji +.i. r4 5 I ~i z '~ ~ Fig r-. ' i e ~' } it v 34 n 3 3 I -l __ _' ^h a ~o w 5 r yam, a %- a is I 1 ~ ~ ;~'~ I .. t w~ y ~. _. w s Q f I O a i C 5' _ _~ :i. r n /~ ~~ -i $" i / ea~~ s o _ i _ 3q6 _ __ _ I _.. b o { -- m 1 0 ;l a 3 e _\iti 10 ~ a I '~ u '~ ~ m BERRY VALL~Y DR ~ I I i 7 ~ If 17 ,, ~~.a . I ~, ~ 0 j 0 6 z 0 j u ~ m v~-. __ _-_ -_412.+4-Pko-- -- _._ - oN. ~<d ~ ~~ ~, 111 03~ z lI ~ ~, '' I Appendix 3 FEMA Map i a ;; ~ v~ ^ fD e W o ~ ~ ~ a, rpp o m ~ N W ` W H ~ Z O W N G Y -~ -a~ c W w ~ ~' H J M W 0 ~ W Z m `~ z ~ Zi ~ W e 'f 6~ F W ~ ~~ V d d b8 w = z 0 0 z LL F g a m ~ E"^ U d F u.l u W e g N o ° tq ~ Z O w o.. go s $ c x O~ ~ v: a -w 0; i i o o ~ 8 0 LL ~ z LV ~ U ~" "~ ~ o $ s = w N __ PeELL bn€. X W Z O N x w X w Z W W Z Z ~ O N w Z O N iY ~s ~~ x d~ W m N 6YK,~io, o O Q W 2 Appendix 4 Facility Summary Forms THURSTON COUNTY REGION FACILITY SUMMARY FORM Complete one (1) for each facility (detention/retention, coalescing plate flter, etc.) on the project site. Attach 8 1/2 z 11 sketch showing location of facility. Proponent's Facility Name or Identifier (e.g., Pond AJ ....... .......: Biofiltration Swale and Infiltration Trench Name of Road or Street to Access Facility ................ ...... Longmire St SE Hearings Examiner Case Number :...................... ..... . Development Rev. Project No./Bldg. Permit No .:........... ..... . Parcel Number .............. .. ..... ..... .. .. .. ...... .. .. .. 21724410200 To be completed by Utility Staff: Utility Facility Number Project Number (num) Parcel Number Status: (num, tch) Q Known; 1, Public; 2 Unknown; 3, Unassigned Basin and Sub basin: (num, 6ch) (2ch for basin, 2ch for sub basin, 2ch future Responsible CITY: (alpha, 1ch) Part 1 -Proiect Name and Proponent Project Name ........................ ........ Yelm Townhomes Project DEVELOPER ................ ......... GMS Construction Corporation Project Contact . ..................... ........ Robert Sageman Address . ......................... ........ P.O. Box 420 Spanaway, WA 98307 Phone ......... ..... .. .. .. .. ..... .. ..... ... (253)606-4935 Project Proponent (if different) ........... ....... Same Address ...... .. ....... ..... ...... .. .. ... ... Same Phone ....... .. .. ..... .. ......... .. ..... ... Same Project Engineer . .. ... .. .. .. .. .. ..... ... ..... Clint Pierpoint Firm ............ .. .. ...... .... ..... ........ KPFF Consulting Engineers 360-292-7230 Part 2 -Proiect Location Section(s) 24 Township 17 N Range 1 E, Willamette Meridian Bldg.): W HPA ^ COE 404 Wetlands ^DOE Dam Safety t ^Floodplain dine Mgmt ^ROCkery/Refaining Wall ~achment ®Grading Other Agencies (Federal, State, Local, etc.) that have had or will review this Drainage Erosion Control Plan: N/A Part 4 -Prooosed Project Description What stream basin is this project in (e. g., Percival, Woodland)........ Yelm Creek Project Size, acres .......................................... 1.00 Ac Zoning ................................................... R-14 On-site: Residential Subdivision.' Number of LOts :........................... . 1 Lot size (average), acres :................... . Building Permit/Commercial :............................ . Building Footprint, acres :................... . 0.30 Concrete Paving, acres ::.................. . 0.24 Greve) SuAace, acres ::.................... . Lattice Block Paving, acres :.:................ . Porous paving, acres Public Roads (including gravel shoulder), acres :............. . Private Roads (including gravel shoulder), acres :............ . On-site Impervious Surtace Total, acres :.................... 0.54 Part 5 -Pre-Developed Project Site Characteristics Stream through site, y/n : .............................................NO Name: ............................................N/A ONR Type: ..................... .. .... .... ... .... .. .. ..N/A Type of feature this facility discharges fo (i. e., lake, stream, intermittent stream, Groundwater pothole, roadside ditch, sheefFlow to adjacent private property, etc.).' Infiltretion into ground, y/n :........................... .... Yes Swales,Ravines,Y/n ::............ .... ... ... .... .... ... No Steep slopes (steeper than 15%) y/n :................. ... No Erosion Hazard, y/n :............................... ... No 100 yr. Floodplain, Y/n :..................... ........ ... No Lakes or Wetlands, y/n :............................. ... No Seeps/Springs,Y/n ::. .... ........... ... .......... .. . .. No High Groundwater Table, y/n :........................ ... No Wellhead Protection or Aquifer Sensitive Area, y/n:........ .. No Part 6 -Facility Description - Biofiltration Swale Total Area Tributary to Facility Including Off-site (acres) :........ .... 1.00 ac Total On-site Area Tributary to Facility (acres) :............... .... 1.00 ac Design Impervious Area Tributary to Facility (acres) :........... .... 0.54ac Design Landscaped Area Tributary to Facility (acres) :.......... .... 0.46 ac Design Total Tributary Area to Facility (acres) :................ .... 1.00 ac Enter a one (1J for the type of /acility: ) :..................... .... . Wef pond deten[ion ............................... ..... Wet pond water surface area ........................ ... . Orypond detention ............................... ..... Underground detention ............................ ..... Infiltretion pond ................................... ..... Dry well infiltration ................................ .... . Coalescing plate separator ......................... .... . Centrifuge separator .............................. ..... Biofilter ......................................... ..... 1 Other............ Outlet type (Enter a one (1) for each type present) Filter ................. ...... ...... ... ........ .. . ..... Oil water separator ............ ......... .. .. .. .... . ..... Single orifice .............. .. .. .. ...... ... .... .... ... .. Multiple orifiice .................................... .... . Weir ........................... .. ........... ... . .... Spillway .............. ... .. .. .. ........... .. .... ..... Pump(s) .................. ........ .. .... ..... ... .... .. Other (conveyance to Infiltration Trench) .............. ........1 Part 6 -Facility Description -Infltration Trench Total Area Tributary to Facility Including Off-site (acres) :........ .... 1.00 ac Total On-site Area Tributary to Facility (acres) :............... .... 1.00 ac Design Impervious Area Tributary to Facility (acres) ............ .... 0.54 ac Design Landscaped Area Tributary to Facility (acres) :.......... .... 0.46 ac Design Total Tributary Area to Facility (acres) :................ .... 1.00 ac Enter a one (1J for the type of facility J :...................... ... . Wetpond detention ...... ..... ...... ........... ... . .... Wetpond water surtace area ........................ .... Orypond detention .............. ..... .. .. .. .. .... ..... Underground detention ... ... .. ...... ........... ... . .... Infiltration pond ......... ..... .. .. ......... .... .... ..... Dry well infiltration ................................ .... . Coalescing plate separator ......................... .... . CenM(uge separator .......... ... ........ .. .. ... ... .... Biofilter ......................................... ..... Other............ Infiltafion Trench 1 Outlet type (Enter a one (1) for each type present) Filter ........................ .. ...... ......... .. ..... Oil water separator ................................ ..... Single orifice ................ .... ... .... .. .... .... ..... Multiple orifice .................................... .... . Weir .................. ... .. .... .. .. .... ..... .... .... Spillway ......................................... .... Pump(s) ....................... ... .... .. .. .. .... ...... Other (infiltration fo groundwater) ..................... ..... 1 Part 7 -Release to Groundwater Design Percolation Rate to Groundwater (r(applicableJ............ 20 inches/hour Appendix S Soils Evaluation Report ~/jam ~%/ j ~~~~ ~, i', ~ i/i/ i~ ~~~j„ice ~% %/~i~ ~ ~j REPORT _ / /%;~~j ~ jij%/~ /~ ~~~~~i ~ GEOTECHNICAL ENGINEERING SERVICES i /~-%~~/~ PROPOSED YELM TOWNHOMES DEVELOPMENT ~~ ~~~ %~~ 304 LONGMIRE STREET SE O ,O ~~~ ~~~ YELM, WASHINGTON i is~~i %/ice '~ ! ~~ MqY 19, 2006 i i,~; j%~/ iiij, KPFF CONSULTING ENGINEERS i,' /;S' _ -_ V i , ~-~~~ ~ i ~ ~ ~ i~ -~ ~~~ ~ j~~j~~~~~~~ ~ .. ~~; -~ ~~~ / ice: ~ ~ ~ ~ _~ /%%/ / ~~ A~ V, , i i~ ~~ _ - /i ~~ 'ii i' ~' '~' i~ I - i iii - i ~ ~ ~~ iii' ~i ~,~ i i l ~~ j4, ~ _-- //i -- ~, . j ,. slei~o~isznoolan~ Geotechnical Engineering Services File No. 15252-001-00 May 19, 2006 Prepared for: - KPFF Consulting Engineers 4200 6th Avenue SE, Suite 309 Lacey, Washington 98503 Attention: Clint Pierpoint Prepared by: GeoEngineers, Inc. 1101 South Fawcett Avenue, Suite 200 _ Tacoma, Washington 98402 (253)383-4940 GeoEngineers, Inc. ~~~- Grp /~~_ Eric W. Heller, LG, EIT Geotechnical Engineer Garry H. Squires, PE, LG, LEG Principal EWH'GHS_jlltt TACO-\I S\15252001\00\Finals\I525200100R doc Dlmlaimer_ Any electronic form, fewimile or hard copy of Ne original documwt (email, IexS tablq and/or figum), if provided, and any atrechmenh arc only e wpy of the original document. The original documwt is pored by CeoEngincer; Inc. and will serve as Ne of6nal document of rewrd. FI[e No_ (5151-0O1-00 TABLE OF CONTENTS Paae No. INTRODUCTION .......................................... _... _.................... _...................................... _............................1 PURPOSE AND SCOPE ...............................................................................................................................1 GEOLOGY REVIEW ......................................................................................................................................2 SITE CONDITIONS ........................................................................................................... ............................2 PROJECT LOCATION ............................................................................................. _. ............................2 SURFACE CONDITIONS ....................._..._................_......................_.................. ..... _........... _........2 SUBSURFACE EXPLORATIONS............_ ................_............._............................ ............................2 SUBSURFACE CONDITIONS ................................................................................. ............................3 CONCLUSIONS AND RECOMMENDATIONS ................................................................. ............................3 GENERAL ................................................................................................................ ............................3 SITE DEVELOPMENT AND EARTHWORK ........................................................... ............................3 General ........................................................................................................... ............................3 Stripping and Clearing ..................................................................................... ...........................3 _ Subgrade Preparation ..................................................................................... ...........................3 Temporary Excavation Support and Groundwater Handling .......................... ...........................4 Permanent Cut and Fill Slopes ....................................................................... ...........................4 _ Surtace Drainage ............................................................................................ ...........................4 Erosion Control ...................................._........_.......................................... _... ................._......_5 FILL MATERIALS ..................................................................................................... ...........................5 General ............................................................................................................ ...........................5 Pipe Bedding ................................................................................................... ...........................5 Trench Backfill............_...._......_ ......................_......_........................_........... ................... . .......5 Use of On-Site Soil as Fill .................................................................... _ ........... ...........................6 FILL PLACEMENT AND COMPACTION ................................................................. ...........................6 General ............................... _...... _.................................................... _.. _......... ...........................6 Area Fills and Bases ..................................................__.................._............. ......................._..6 Trench Backfll ............................_................_......._................._......_.._........ _ .................... 6 SEISMIC DESIGN CONSIDERATIONS .................................................................... ...... ..........................6 General .................................................................. ........................................... ......................... .6 Seismic Design Criteria ................. ................................................................... Liquefaction Potential....... ..........................7 _........_ ..........................................._........_............. FOUNDATION SUPPORT ..... . _................_.....7 ....................................._........................._.................. General... ..........................7 ..... .. ....... Spread Footings .. ..... . . 7 . ..... Lateral Load Resistance ... .... 8 ........................_.............................................._..... ettle ment... _ ......... ... _...... .......8 .......... _........................ _.... _........................ _.................... FLOOR SLABS .............. .......... _..............8 _........................ _................ _... ._..........._............._.. ........... RETAINING WALLS .......... .........................8 ................................._.............................._..........._....... _ Drainage ....................... _........ . .........................9 _ _....................................................... _............. Design Parameters .............. .................... _...9 .... .. ......... ... ... ... _........_ ............ STORMWATER INFILTRATION.... .........................9 ........_...._ .............._......................__.................. .......... ..............9 Fde No. 151ST-00l-00 page ~ .Llay IQ 1006 ~i EOENGINEER~ TABLE OF CONTENTS (CONTINUED) Pace No. _. ASPHALTIC CONCRETE PAVEMENT RECOMMENDATIONS ........................... ...........................10 General .......................................................................................................... ...........................10 Design Assumptions ..................................................................................... ...........................10 - LIMITATIONS ................................................................................................................... ...........................11 List of Tables Table 1. Seismic Design Parameters 200316C ...........................................................................................7 Table 2. Soil Infltration Rates Grain-Size Distribution Analysis ............................................ _...................10 List of Figures Figure 1. Vicinity Map Figure 2. Site Plan APPENDICES APPENDIX A-SUBSURFACE EXPLORATIONS AND LABORATORY TESTING ................................ A-1 Appendix A Figures Figure A-1. Key to Exploration Logs Figures A-2 through A-B. Log of Test Pits Figure A-g. Sieve Analysis Results APPENDIX B -REPORT LIMITATIONS AND GUIDELINES FOR USE ......................................... B-1... B-4 AIe T'a. 625I-001-00 PugE & May 19,1006 GEOENGINEEq~ REPORT GEOTECHNICAL ENGINEERING SERVICES PROPOSED YELM TOWNHOMES DEVELOPMENT SO4 LONGMIRE STREET SE YELM, WASHINGTON FGR KPFF CONSULTING ENGINEERS INTRODUCTION This repoR presents the results of our geo[echnical services for the proposed townhouse development located at 304 Longmire Street SE in Yehn, Washington. The project site is located southeast of the intersection of Longmire Street SE and Berry Valley Road SE as shown on the ViciniTy Map, Figure 1. Our understanding of the project and project site is based on information provided by you, an initial site visit on Mazch 3, 2006, and our experience in the Yelm area. We understand preliminary development plans call for up to ten new townhouse residences on the site. Basement levels might be included in some or all of the structures. Road construction including installation of concrete curb and gutter was m progress on Longmve Street SE at [he time of our initial site visit. PURPOSE AND SCOPE The purpose of our services is to evaluate soil and groundwater conditions as a basis for developing design criteria for geotechnical aspects of the proposed project. Our specific scope of services for this study includes the following: 1. Reviewing readily available published geologic data and our in-house files for existing information on subsurface conditions in the project vicinity. 2. Locating and coordinating clearance of existing utilities. We contacted the "One-Call Underground Utility Locate Service" prior to beginning explorations. 3. Exploring soil and groundwater conditions at the project site by excavating seven test pits to depths of 8-I/2 to 10 fee[ using a subcontracted rubber-tired backhoe. 4. Perfomring laboratory tests on selected soil samples obtained from the explorations to evaluate pertinent engineering characteristics. The laboratory test program consisted of moisture content determinations and grain-siu analyses. 5. Providing a discussion of the subsurface soils encountered, inclnding the depth, composition, and supporting capacity of existing fill. 6. Providing recommendations for site preparation and earthwork, including clearing and stripping, temporary and permanent cut slopes, suitability of on-site soils for use as structural fill including constraints for wet weather construction, specifications for imported soil for use as structural SII, and fill placement and compaction requirements. 7. Providing recommendations for site drainage and control of groundwater that may be enconntered. We include an opinion regarding stormwater infiltration potential of site soil based on our observations and laboratory testing. File No. 5251-001-00 page j Ma~~ IQ 2006 GEOENGINEERS~ _- 8. Providing recommendations for shallow foundations, including allowable soil bearing pressures, settlement (total and differential) estimates, lateral earth pressures and coefficient of friction for evaluating sliding resistance. 9. Providing recommendations for support of on-grade floor slabs, including capillary break, vapor retarder, underslab drainage, and modulus of subgrade reaction, as appropriate. - 10. Providing recommendations for design of below grade and retaining walls, including lateral earth pressures and wall drainage criteria. 11. Discussing seismic considerations, including seismic design criteria consistent with the International Building Code and our opinion of the liquefaction potential of site soils. 12. Providing recommendations for asphalt concrete pavement (ACP) design, including base and subbase requirements for the proposed parking areas and driveways. We provide typical minimum ACP section recommendations based on our experience. 13. Commenting on anticipated construction difficulties identified from the results of our site sNdies. GEOLOGY REVIEW Based on review of available published geologic maps, glacial soil deposits underlie the project site and surrounding area. The Geologic Map of Thurston County, Washington, East Half (Plate 2) (Noble, 1960- 62) indicates the site is underlain by Vachon glacial recessional outwash (Qvr). This material was deposited as the Vachon Glacier receded. Qvr generally consists of poorly sorted sand and gravel. SITE CONDITIONS PROJECT LOCATION The proposed Townhomes project is located at 304 Longmve Street SE in Yelm, Washington, in Township lIN, Range 1$ Section 24 (Willamette Meridian). The site is located southeast of the intersection of Longmire Street SE and Berry Valley Road SE, as shown on Figure 1. SURFACE CONDITIONS The site comprises a partly developed, relatively level about an acre parcel that is bounded on [he northeast and southeast by existing residential property. Longmire SVee[ SE forms the northwest site boundary and an existing golf course bounds the property [o the southwest. An abandoned single-family residence is located in the north comer of the property. The remainder of the site is covered with grass and shrubs with a few trees. SUBSURFACE EXPLORATIONS We explored subsurface conditions at the site by excavating seven test pits on April 11, 2006 using a rubber-tire backhoe subcontracted by GeoEngineers. The test pits were excavated to depths of 8-1/2 [o 10 fee[ below ground surface (bgs) at the approximate locations shown on Figure 2. Amore detailed description of the exploration methods and procedures is presented in Appendix A. Figure A-1 presents a key to the exploration logs. Logs of the tests pits aze presented as Figures A-2 though A-g. Laboratory test methods and results are also included m Appendix A. F;le No. 15252-001-00 page 2 .47ay J9, 2006 ~i EOENGINEERS~ SUBSURFACE CONDITIONS We Typically encountered materials we interpret to be recessional glacial outwash except at the location of test pits 3 and 4 where we encountered some existing fill material. The fill in the test pits consists of fine to coazse sand, with silt and cobbles, occasional organic material (roots and twigs), and some debris consisting of bazbed-wire fence, clay pipe, brick, and garbage (cans, bottles, and golf balls). The fill was generally observed to extend to depths of 2 to 2-1/2 feet bgs. Below the fill, where present, or from ground surface, we enwuntered native soil that typically consists of dense silty sand, fine to coarse gravel with sand, or fine to coarse sand with silt. All soil types contain variable amounts of gravel, cobbles, boulders and silt. We interpret these materials to be recessional outwash. No groundwater was observed in our explorations. - CONCLUSIONS AND RECOMMENDATIONS GENERAL Based on our observations, it is our opinion that the proposed townhomes can be constructed generally as envisioned. Based on our explorations, i[ is our opinion on-site infiltration of stormwater is feasible at this site. We recommend using an infiltration rate of 20 inches per hour. The following sections provide geotechnica] recommendations for design and consWCtion of the proposed improvements. The existing fill must be removed to firm and unyielding native soil where present below proposed parking Subgrades and within building areas. SITE DEVELOPMENT AND EARTHWORK General We anticipate that site development work will include removing existing vegetation; demolishing the - existing structure; excavating for utility trenches; removing existing fill es necessary and placing and compacting fill and backfill materials. We expect that the mejoriry of site grading can be accomplished with conventional earthmoving equipment in proper working order. The following sections provide recommendations for earthwork, site development end fill materials. Stripping and Clearing Based on our explorations, we anticipate stripping and clearing at this site will be required to remove the existing organic-rich topsoil from structural areas. Stripping should extend at least 5 fee[ beyond all stmctural areas such as buildings and pavement areas. We estimate that the depth of stripping will generally be on the order of 6 inches. Greater stripping depths maybe required to remove localized zones of loose or organic soil, or if stripping operations cause excessive disturbance to Subgrade soil. Subgrade Preparation The existing fill on [he site must be removed prior to Subgrade preparation. Subgrades should be thoroughly compacted [o a uniformly firm and unyielding condition on completion of stripping and 51] removal and before placing stmctural fill to establish design grade. We recommend Subgrade soil be proofrolled prior to the placement of fill or other structural elements as described below. We recommend [hat prepared Subgrades be observed by a member of our firm, prior [o placement of fill or pavement base. Our representative will evaluate the suitability of the Subgrade and identify areas of File No. tszsz-om-ao page g May 19, 2006 GEGENGINEEgS~ yielding, which are indicative of soft or loose soil. The exposed subgrade soil should be proof-rolled with heary rubber-tired equipment. If sofr or otherwise unsuitable areas are revealed during proof-rolling or probing that cannot be compacted to a stable and uniformly firm condition, we recommend that: 1) the - subgrade soils be scarified (e.g., with a ripper or farmer's disc), aerated and recompacted; or 2) [he unsuitable soils be removed and replaced with s[rucmral fill, as needed. Temporary Excavation Support and Groundwater Handling Based on our explorations, shallow excavations will likely cave unless the sides are appropriately sloped. Excavations deeper than 4 feet should be shored or laid back at a stable slope if workers are required to enter. Shoring and temporary slope inclinations must conform to the provisions of Title 296 Washington Administrative Code (WAC), Part N, "Excavation, Trenching and Shoring." Regardless of the soil type encountered in the excavation, shoring, trench boxes or sloped sidewalk will be required under Washington Industrial Safety and Health Act (WISHA). The contract documents should specify that the contractor is responsible for selecting excavation and dewatering methods, monitoring the excavations for safety and providing shoring, as required, to protect personnel and structures. 1n general, temporary cu[ slopes should be inclined no steeper than about I-1/2H:1 V (horizontal:vertical). This guideline assumes that all surface loads are kept at a minimum distance of a[ least one half the depth of the cut away from the top of the slope and that significant seepage is not present on the slope face. Flatter cut slopes will be mecessary where significant seepage occurs or if large voids are created during excavation. Some sloughing and raveling of the cut slopes should be expected. Temporary covering with heary plastic sheeting should be used to protect slopes during periods of wet weather. Groundwater was not encountered in the exploratioms. Based on our explorations, we expect groundwater should not be a major factor during shallow excavations and earthwork. We anticipate that the groundwater handling needs will generally be lower during the late summer and early fall months. We anticipate that shallow perched groundwater can be handled adequately with sumps, pumps, and/or diversion ditches, as necessary. Ultimately, we recommend that the contractor performing [he work be made responsible for controlling and collecting groundwater encountered. Permanent Cut and Fill Slopes Tn general, we recommend that permanent cut and fill slopes be constmcted a[ a maximum inclination of 2H:1 V. Whera 2H:1 V permanent slopes are not feasible, retaining structures should be considered. Cut areas should be re-vegetated as soon as practical to reduce [he surface erosion and sloughing. Temporary protection should be used until permanent protection is established. I£ fill slopes aze constructed, wa recommend they be overbuilt slightly and subsequently cut back to expose well compacted fill in order to achieve uniform compaction. Surface Drainage Surface water from roofs, driveways and landscape azeas should be collected and controlled. Curbs or other appropriate measures such as sloping pavements, sidewalks and landscape areas should be used to direct surface flow away from the buildings, and erosion sensitive areas. Roof and catchment drains should discharge to an appropriate collection system. no. l~~ee~m~o Page 4 May 19,1006 Ci EOENGINEERS~ Erosion Control Based on existing site grades and the proposed development, we anticipate that erosion control measures such as silt fences, straw bales and sand bags will generally be adequate for the proposed development. However, if construction and grading is staged, slopes may be created and additional erosion control measures may have to be implemented. Temporary erosion wntrol should be provided during oonstmcfion activities and until permanent erosion control measures are functional Surface water runoff should be properly contained and channeled using drainage ditches, berms, swales, and tightlines and should no[ discharge onto sloped areas. Any disturbed sloped areas should be protected with a temporary covering until new vegetation can take effect. Jute or coconut fiber matting, excelsior matting or clear plastic sheeting is suitable for this purpose. Graded or disturbed slopes should be tracked in-place with the equipment running perpendicular [o the slope contours so that the track grouser marks provide a texture to help resist erosion. Permanent measures for erosion control should include reseeding or replanting the disturbed areas as soon as possible and protecting those areas until new vegetation has been established. Permanent site grading should be accomplished in such a manner that stormwater runoff is not concentrated and surface water is not duetted to sloped portions or into excavated areas of the site. This can be accomplished by grading the site to direct the flow to appropriate collection points away from the slopes or excavations. Tightlines should be used where necessary to direct storm or other surface water across sloped areas. Tightlines should be anchored on slopes 15 percent or steeper. FILL MATERIALS General Material used for fill should be free of garbage debris, organic contaminants and rock fragments larger than 6 inches. The workability of material for use as structural fill will depend on the gradation and moismre content of the soil. As the amount of fines (material passing the U.S. Standard No. 200 sieve) increases, soil beoomes increasingly more sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible [o achieve. If construction is performed during we[ weather conditions, we recommend using fill consisting of well-graded sand and gravel containing less than 5 percent fines by weight based on the minus 3/4-inch fraction. If prolonged dry weather prevails dining the earthwork phase of constmc[ioq a somewhat higher fines content may be acceptable. Pipe Bedding Trench backfifl for the bedding and pipe zone should consist of well-graded granular material with a maximum particle size of 3/4-inch and less than 5 percent passing the U.S. Standard No. 200 sieve. The material should be free of roots, debris, organic matter and other deleterious material. Trench Bac~ll We recommend that all trench backfill consist of material of approximately the same quality as "gravel borrow" described in Section 9-03.14(1) of the Washington State Department of Transportation (WSDOT) Standard Specifications. All fills should be constructed in horizontal lifts a[ the appropriate thickness for compaction. For compaction recommendations refer to the "Fill Placement and Compaction" section ofthis report. File No. 15252-00/-00 Page 5 May 19, 2006 GfOENGINEERS~ Use of On-Site Soi/ as Fill Based on our subsurface explorations, we conclude that the inorganic mineral native soil may be considered for use as structural fill, provided it can be placed and compacted as recommended. The existing 51I is no[ suitable for reuse as structural fill unless all deleterious material is removed. Some of the site soils were observed to have relatively high fines contents, which may make them difficult or impossible to compact when wet or if earthwork is performed during periods of extended we[ weather. FILL PLACEMENT AND COMPACTION General Structural fill should be compacted at a moisture content near optimum. The optimum moisture content varies with [he soil gradation and should be evaluated during constmction. Silty soil and other fine granular soil such es silty sand, silty gravel, sand with silt and gravel with silt can be difficult or impossible to compact during persistent wet conditions. Fill and backfill material should be placed in uniform, horizontal lifts, and uniformly densiEed with vibratory compaction equipment. The maximum lifr thickness will vary depending on the material and compaction equipment used, but should generally not exceed 10 to 12 inches in loose thickness. Area Fills and Bases Structural fill placed to raise site grades and aggregate base materials under foundations, slabs and pavements should be placed on a prepared subgrade that consists of uniformly firm and unyielding inorganic native soils or compao[ed fill. Structural fill should be compacted to at least 95 percent of the maximum dry density (IvIDD) determined by ASTM Test Method D 1557 (modified Proctor). Trench Bac~ll For utiliTy excavations, we rewmmend that the initial lift of 5I1 over the pipe be thick ewugh [o reduce the potemial for damage during compaction but generally should not be greater than about 18 inches. In addition, rock fragments greater than about 1 inch in maximum dimension should be excluded from this lift. In building areas, trench backfill should be uniformly compacted in horizontal lifts to at least 95 percent of the MDD (ASTM D 1557). Fill placed below a depth of 2 fee[ in pavement areas should be compacted to at leas[ 90 percent of the MDD (ASTM D 1557). In nonstructural areas, trench backfill should be compacted [o a firm condition that can support construction equipment. Suitable native soils or select granular soils should be acceptable in non-structural azeas. SEISMIC DESIGN CONSIDERATIONS General The site is located within the Puget Sound region, which is saismioally aotive. Seismicity in this region is attributed primarily to the interaction between the Pacific, Juan de Fuca and North American plates. The Juan de Fuca plate is subducfing beneath the North American plate. It is thought that the resulting defortuation and breakup of the Juan de Fuca plate might account for the deep focus earthquakes in the region. Hundreds of earthquakes have been recorded in the Puget Sound area. 1n recent history, four of tue rva. tszs2-am-oo Page 6 May 19, 2006 GEOENGINEERS~ these earthquakes were large events: 1) in 1946, a Richter magnitude 7.2 earthquake occurted in the Vancouver Island, British Columbia area; 2) in 1949, a Richter magnitude 7.1 earthquake occurred in the Olympia area; 3) in 1965, a Richter magnitude 6.5 earthquake occurted between Seattle and Tacoma; and 4) in 2001 a Richter magnitude 6.8 earthquake occurred m Nisqually, near Olympia, Washington. Research is presently underway regarding historical large magnitude subduction-related earthquake - activity along the Washington and Oregon coasts. Geologists are reporting evidence that suggests several large magnitude earthquakes (Richter magnitude 8 [0 9) have occurred in the last 1,500 years, [he most recent of which occurred about 300 years ago. No earthquakes of this magnitude have been documented - during the recorded history of the Pacific Northwest. Seismic Design Criteria We understand seismic design will be performed using the 2003 IBC standards. The following parameters should be used in computing seismic base shear forces: Table 7. Seismic Design Parameters 2003 IBC Spectral Response Accel. al ShoR Periods (SS) = 1.15 Specral Response Accel, al 7 Sewntl Periods (St) = 0.38 Site Class = C Site Coefficient (FA) = 1.0 Site Cceffcient (FV) = 1.3 Liquefaction Potential Liquefaction refers to a condition where vibration or shaking of the ground, usually from earthquake forces, results in development of excess pore pressures in saturated soils and subsequent loss of strength in the deposit of soil so affected. Tn general, soils that are susceptible to liquefaotion include loose to medium dense "dead' to silty sands that are below the water table. 1n our opinion, the potential for liquefaction at the site is low. FOUNDATION SUPPORT Genera/ The proposed Townhomes may be satisfactorily founded on continuous wall or isolated column footings established on undisturbed native soil or on structural fill that extends to undisturbed native soil. As discussed above, we recommend existing fill be overexcavated and replaced with structural fill where 511 is present et or below foundation grades. The overexcavation must extend laterally beyond the footing perimeter a distance equal to the excavation depth below foundation Bade, or 3 feet, whichever is less. We recommend a minimum width of 16 inches for continuous wall footings and 2 fee[ for isolated column footings. All footing elements should be embedded at least 18 inches below the lowest adjacent external grade. We recommend installing footing drains to collect and remove possible seasonal perched groundwater. N'e recommend that a member from our firm observe all foundation excavations before placing formwork and reinforcing steel in order to confirm that the bearing surfaces have been adequately prepared and that File No. 15251-0 0 /-0 0 page ~ May 19, 4006 GEOENGINEEa~ the soil conditions are as anticipated. Unsuitable foundation subgrade soils should be recompacted or removed and replaced with compacted structural fill as directed by the geotechnical engineer. Spread Footings Footings founded as described on undisturbed native soil or compacted structural fill may be designed using an allowable soil bearing pressure of 3,000 pounds per square foot (psf). This value applies to long-term dead and live Toads exclusive of the weight of the footing and any overlying backfill and may be increased by one-third when considering total loads, including transient Toads such as those induced by wind and seismic forces. Lateral Load Resistance Lateral loads on foundation elements may be resisted by passive resistance on the sides of footings and other below-grade structural elements and by friction on the base of footings. Passive resistance may be estimated using an equivalent fluid densiTy of 300 pounds per cubic foot (pcf), assuming that the footings and below-grade elements are backfilled with structural fill placed and compacted as recommended. Frictional resistance may be estimated using 0.4 for the coefficient of base friction. The above values include a factor of safety of about I.S. Settlement Based on Typical residential construction loads, we estimate that settlement of footings designed and constructed as recommended should be less than 1 inch with differential settlements between comparably loaded isolated footings or along 50 feet of continuous footing of I/2 inch or less. Most of the settlements should occur essentially as loads are being applied. Loose or soft soil below footings or disturbance of foundation subgrade during construction could result m larger settlements than predicted FLOOR SLABS A modulus of subgrade reaction of 300 pounds per cubic inch (pct) can be used for designing the building floor slab provided that the subgrade consists of undisturbed native soil or structural fill and has been prepazed in accordance with the "Site Development and Earthwork" section of this report. Settlements for the floor slab designed and constructed as recommended are estimated to be less than I inch. We estimate that differential settlement of the floor slabs will be 1/2 inch or less over a span of 50 feet providing that the fill below the slab is compacted as specified, and the preload/surcharge is completed as discussed above. We recommend [hat on-grade slabs be underlain by a minimum 6-inch-thick capillary break layer to reduce the potential for moisture migration into the slab. The capillary break material should consist of a well-graded sand and gravel or crushed rock with a maximum particle size of 3/4-inch and less than 5 percent fines. The material should be placed as recommended in the "Fill Placement and Compaction" section of this report. If dry slabs are required (e.g., where adhesives are used to anchor carpet or the to the slab), a waterproof liner may be placed es a vapor barrier below the slab. A 2-inch thickness of clean sand can be placed over the vapor barrier to protect the liner and serve as a leveling course. Fife h'o. 15151-0 01-0 0 page g May 19, 2006 GEOENGMEERS~ RETAINING WALLS Drainage Positive drainage is imperative behind any retaining structure. This can be accomplished by placing a zone of free draining material behind the wall with perforated pipes to collect seepage. The drainage material should consist of coarse sand and gravel containing less than 5 percent fines based on the fraction of material passing the 3/4-inch sieve. The wall drainage zone should extend horizontally a[ least 18 inches from the back of the wall. A perforated smooth-walled rigid PVC pipe having a minimum diameter of 4 inches should be placed a[ the bottom of the drainage zone along the entire length of the wall, with the pipe invert at or below the elevation of the base of the wall footing. The drainpipes should discharge to a tightline leading to an appropriate collection and disposal system. An adequate number of cleanou[s should be incorporated into the design of the drains in order to provide access for regular maintenance. Roof downspouts, perimeter drains or other Types of drainage systems should not be connected to retaining wall drain systems. Design Parameters The pressures presented assume that backfill placed within 2 feet of the wall is compacted by hand- operated equipment to a density of 90 percent of the MDD and that wall drainage measures aze included as previously recommended. For walls constructed as described above, we recommend using an active lateral earth pressure corresponding to an equivalent fluid densiTy of 35 pounds per cubic foot (pcf) for the level back£11 condition. For walls with backfill sloping upward behind the wall at 2H:1V, an equivalent fluid density of 55 pcf should be used. This assumes [hat the tops of the walls are not structurally restrained and are free to rotate. The above values are for walls that retain native soil. For the at-rest condition, an equivalent fluid density of 55 pcf should be used. The recommended values do not include the effects of surcharges from surface loads. Appropriate factors of safety should be applied to these values with respect to bearing capacity, sliding and overturning. If vehicles will be operated to within one-half the height of the wall, a traffic surchazge should be added to the wall pressure. The traffic surcharge can be approximated by the equivalent weight of an additional 2 feet of backfU behind the wall. Retaining walls founded on structural fill may be designed using the allowable soil bearing values and lateral resistance values presented above in the "Shallow Foundation Support" section of this report. We estimate settlement of retaining structures should be similar to the values previously presented for building foundations, provided preloading and surcharging is performed as discussed above. STORMWATER INFILTRATION Select soil samples obtained from Test Pits 1, 3, 5 and 7 were tested in general accordance with ASTM D 422 to determine the grain size distribution. The results of the grain size distribution testing are presented in Appendix A, Figure A-6. We compared these results with the stomwater rates presented in The 1992 Department of Ecology Stormwater Management Manual for the Puget Sound Basin. Design storrnwater in&Itration rates for the soil samples obtained are provided in the table below. File No. !5252-001-00 page y - May 19, 2006 GEOENGINEE0.5~ Table 2. Soil InNltration Rates Grain-Size Distribution Analysis' Soil Approximate Soii Sample Elevation' of Recommended Test Sample Depth Sample Soil USCS SOiI InfilVation Rate' Pit No. No. (feet) (feet) Description Classification (Inches per hour) 1 2 5.5 344 Sand, Gravel antl GP 20 Cobbles 3 3 9.5 332.5 Sand, Gravel and GW 20 Cobbles 5 2 4.5 336.5 Banq Gravel and GW 20 Cobbles ~ 3 9.5 336.5 SanO, Gravel and GW-GM 20 Cobbles Notes: ' For selected soil samples. ' Basetl on grain-size analysis in accortlance with procedures oullinetl for ASTM D 422 antl in the 1992 Depanment of Ecology Stonnwater Management Manual For The Puget Sound Basin, Table 7 2. 'Basetl on Topographic Survey provided by KPFF Consulting Engineers, Inc. The values presented above are for the samples obtained in a particular azea at a particulaz elevation and represent an estimate of design infiltration rates. Location speciSc field or laboratory infiltration testing in accordance with local regulations should be performed to develop fmal design i~ltration values. Stormwater should be treated in accordance with current regulations prior to infiltration. ASPHALTIC CONCRETE PAVEMENT RECOMMENDATIONS Genera/ Pavement subgrades and structural fill should be prepared and placed as previously described. The crushed rock base course should be moisture conditioned near the optimum moisture content and compacted to at least 95 percent of the MDD determined in accordance with ASTM D 1577 test procedures. An appropriate number of in-place density testing should be conducted on the compacted base course to check that adequate compaction has been obtained. Crushed rock base course should conform to applicable sections of4-04 and 9-03.9(3) ofthe WSDOT Standards Spec cations. Design Assumptions Subgrades below the base course must be firm and unyielding. Class A or B asphaltic concrete should conform to applicable sections of 5-04, 9-02 and 9-03 of the WSDOT Standard SpeciFcations. The recommended pavement sections assume [hat fmal improvements surrounding the pavement will be designed and constructed such that stormwater or excess irrigation water from landscape areas does not infiltrate below the pavement section info the crushed base course. Asphaltic Concrete Pavement (Automobile Parking Areas) • Surfacing: 2 inches of Class A or B asphaltic ooncrete. • Base: 4 inches of crushed surfacing base course. • Subgrade: Recompacted native soil or structural fill. Asphaltic Concrete Pavement (Access Driveway) • Surfacing: 3 inches of Class A or B asphaltic concrete. May 1Q 10061001-00 Page tO GEOENGINEER~ • Base: 6 inches of crushed surfacing base course. • Subgrade: Recompacted native soil or struc[ura1511. The recommended pavement sections may not be adequate for heavy construction traffic conditions such loads imposed by concrete transit mixers, dump trucks, or crane loads. Additional pavement thickness may be necessary to prevent pavement damage during construction, and/or repair of damaged pavements should be anticipated. LIMITATIONS We have prepared this report for the exclusive use by KPFF Consulting Engineers and their authorized agents for the Proposed Yelm Townhomes Development project located on Longmire Street SE in Yelm, Washington. Within the limitations of scope, schedule and budget, our services have been executed in aceordanoe with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepazed. No warranty or other conditions, express or implied, should be understood. Please refer to Appendix B titled "Report Limitations and Guidelines for Use" for additional information pertaining to use of [his report. Flle No. 15151-0 01-0 0 POge II May 19, 2006 liEOENGINEEfl~ P/ qre SE pI --~ _ _` 2~ t I ep. i . : 0 ' c m ¢ ~ t s` ~5 I i `> SITE t. ' ~~ I ae~>alla YRC BE ` ~" 3 4 `~ Velm E R h ~ ° 20 ` ` E h }° 4 fi .,F ~ ~ S AP 6 onBm re 515E (, 2 4 P u v E b 1 ~ u a " ~ ~, a > ~ SA O.. ~ BiryTIOn 515 ~" - '~ 10 PceSE ~"' ~ t L~~+E `~ :, e~ ~ Ph aR ~ F` s lOd1A WaY BE 4 9P aq N , l foSlA Way SE ~ N 5g] .4 C w ¢ /..~ t F ~~~~ v ~ TM ~+rya Rtl BE S y~-FC~MY Rtl$ ~ nLn~ '~. F r 109P qve SE s E t F Z: 1 OIA Pve sE ' I ne sne Is located in the SE 1/4 of Section 2r " `~ Township 17 North, and Range o1 East N ... /tea z,ooo 0 2,000 s - ~_ Feet Notes 1. Thelocalions of all lectures shown are approximate. 1 2. This tlrevnng is for information puryoses. If is Intentletl to assist in snowing feaNres tliscussetl in an anacnetl document. GeoEngineers, Inc. - not guarantee Ne actuary antl content of electronic tiles. The master 1 file is storetl by GeoEngineers, Inc. antl will serve as Ne oRmAal recoN o/ Inis communiwliort s. a is unlavRm w mpy o, revroaece an er aey van mereor, wnemer mr ~ personal use or resale, wl0oul permisson. S - Data Sources Inlerstates, stale routes. antl roatls from TIGER 200o. County bountlades, cllies, antl waterbotlles from Department of Erglogy. LamEep Conlo~mal Cmiq WasAington SUte Plane Nonn, NotlA Fmencan DaWm 19E3 GEOENGINEER~ ~ ' ' i; ~ ~ , , ~ ' .~ ~ , ~ . 'i .Y " ~ ~ ' ~ ~ i APPENDIX A SUBSURFACE EXPLORATIONS AND LABORATORY TESTING APPENDIX A SUBURFACE EXPLORATIONS AND LABORATORY TESTING SUBSURFACE EXPLORATIONS Subsurface conditions at the site were explored on April I1, 2006 by excavating seven test pits using equipment and an operator subcontracted to GeoEngineers, Inc. The test pit explorations ranged in depth from 8-1/2 to 10 feet below surrounding site grades. - The locations of the test pits were established in the field by pacing from existing site features such es roadways and existing structures. Locations of the explorations are provided on Figure 2. The elevations presented on the test pit logs are based on interpolation between the contours on the site plan and topographic survey provided by KPFF Consulting Engineers. The locations and elevations of the explorations should be considered approximate. _ The 5eld explorations were performed under the direction of our personnel. Our field representative obtained samples, classified the soils, maintained a detailed log of each exploration and observed groundwater conditions where applicable. The samples were retained in sealed plastic bags. The soils were classified visually in general accordance with the system described in Figure A-1, which includes a key to the exploration logs. Summary logs oFthe explorations are included as Figures A-2 through A-8. The relative densities noted on the test pit logs aze based on the difficulty of excavation and our experience and judgment Laboratory test methods and results are presented below. LABORATORY TESTING General Soil samples obtained from the test pits were transported to GeoEngineers laboratory. Representative soil - samples were selected for laboratory tests to confirn our field classification. The following paragraphs provide a description of the tests performed. Moisture Content The moisture content of selected samples was determined in genera] accordance with ASTM Tes[ Method D 2216. The test results are used to aid in soil classification and correlation with other pertinent engineering soil properties. The test results are presented on the test pit logs at [he respective sample depths. Particle-Size Analyses Particle-size sieve analyses (SA) were performed on selected samples in general accordance with ASTM Test Method D 422. This test method covers the quantitative detertnina[ion of the distribution of particle sizes in soils. The distribution of particle sizes larger than the U.S. No. 200 sieve (7S micrometers) was determined by mechanical sieving. The results of the tests were used to check 5eld soil classifications. Figure A-9 presents the sieve test results. File No. 15252-0 01-0 0 Page A-1 May 19, 2006 GEOENGINEERS~ SOIL CLASSIFICATION CHART MAJOR OMSIONS SYM BOLS TYPICAL GRAPH LErrER DESCRIPTIONS cLEnN op° GW .n.vaEa rs. cx.rE~ GRAVEL GMVELe qNp Gruvauv •w°°^• 901L5 GP ,vat cumuvrur¢a coARSS DM F15 wm GM w._:.xD. GRAINED Fl EG +wtlnw[s SdLa .arew R,„.w GC a.va,_ux rvw,vaaa SW aos.xos. cx.uE... claNSnNOS va urvo nNo raw «e x.r mo wave sANOr SP va. , sons ~ u. a,xv $ANgS wrH SM .xo_H~r nNEs wavE SC zxa. c,.. e«.e xrs ML +xawxr sLrs ANO CL RwE cEw.x.xcc ...:,.,.cu. GRPINFD LIAYe s0115 OL ncua or ~ov.vsvom ~ M H +vv.,cEwc cwn cvw: si. slLrs ano CH avr acx murec, curs "'" mm~ OH omin rc x,cx ruzrmm fiIGHLr ORGgNIL501L5 c~~ PT + ~ "cacw,c com[xia ADDITONAL MATERIAL SYMBOLS SYMBOLS TYPICAL GRAPH LETTER DESCRIPTIONS CC Cement Concrete AC Asphalt Concrete CR Crushed Rock/ puany Spells TS Topsoil) Forest Duff/Sotl C-/ Measured grountlwater level in _ ezploretlon, wel4 or pfezomete Groundwater observetl stoma _ ezplorsnon Perchetl waterobservetl stoma ezplorenon g Measuredfree product in wello _ Piezometer Stratigraphic Contact of of r Olannct nonGCt between soil strati or geologic unfls / Grztlual change between soil strop or geologic canna ____ Approximate loeatlon of soil atroW change within a geologic soil unn _._. __...'._ a............-........w~°ov°c~wmu uue, wn aassmca4wlls Laboratory /Field Tests Sampler Svmbol Descdotions it Peroene ones . 2.4-inch l.D. sole barrel AL CA AtWrbam limes Chemical anatysu CP Laboratory compaction test Standartl Penetmtlon Test (SPT) CS Comolitlatlon test ® Shelb Wbe DS HA Direct shear M tlrometer an l y y ays s MC MolsWre content ® PISWn MD MoisWre wnbnt and tlry tlensey OC Organie coment DIreIX-Push PM Permeability or hytlreulic contluctNity PP Pocket penetrometer ® Bulk orgreb SA Sieve arlaysk T% Tdaxial compreulon UC Unconfined compression Blowcoun[ is rewrdetl for tlriven samplers as Ne number YS Vana shear of blows requiretl b atlvanu sampler t2 Inches (or tlatance noted). See exploroaon log for hammerwelgh[ Sheen Classification antl tlrop. NS No YSibk Sheen A"P"Intliwtes sampler pushetl using the weigh of the SS MS Slight Sheen Motlerete Sheen tlrill rig. HS Heavy Sheen NT Not Tested NOTE'. The reader must referto the tlismssian m Pe repod lexl antl me IDBS of explorations for a proper gntlerslantling of subsutlace contlaions Descriptions on Ne bga apply only of Itle specRC explorefion localipns anG of the lime tae explorations were matle', fbey are nol wanemetl fo be represemalrve of subsl,dace mnaiuons of timer locations w times. KEY TO EXPLORATION LOGS CiEOENGINEERS j/ FIGURER-t Date Excavated: 04/11/06 Logged by: DCR Equipment: Cue Ex[endahoe Backhoe Surface Elevation (h)' 346 ' i MATERIAL DESCRIPTION ° OTHER TESTS ~ r d " " _ e AND NOTES 5- W v pv - E E W E ' _ =_ N N o, U' J o U' In `C U e _ 5 D 4 inches turf, organics, sod Sw-SM Dark brown fine to coarse sand with silt, occasional gravel and organics (dense, moist) 345 Gw Light brown gravel with fine to coarse sand, occasional cobbles, trace sill ~° (devse, morst) D o ~' I D 6 o e Qv D O e pe D o ° ~° z 5 O e Qe 0 0 0 340 ~ ~° D O e Qe O a Qe o0D o Qo 5 o D Pest pi[ comple[ed a[ 8.5 feet on 04/11/06 No groundwater seepage observed Severe caving observed at 8.5 feet 10 335 Notes: See Figure A.l for explanation of symbols. The dep ths on the test pi[ logs aze hazed on an average ofineasuremevts across the test pit and should be considered accurate to QS foot. LOG OF TEST PIT 2 Project: Proposed Yelm Townhomes Development GEOENGINEERS~ Project location: Yelm,Washington Project Number: 15252-001-00 Figure A-3 Sheet 1 of 1 Dale Excavated: 04/11/06 Logged by: DCR Equipment: Case Extendahoe Backhoe Surface Elevation (ft)' 342 `v E 0 z s '' °' v v m m m m E E Wm p°' (O N 0 1 340 2 5 MATERIAL DESCRIPTION SP-SM ~ Dark brown fine to coarse sand wi[h silt, wbbles and gravel, ocdasir orgavirs, occasional barbedwve, bricks, garbage (medium dense, m019I1t~/ Gw Licht brown f e to coarse a OTHER TESTS e.. AND NOTES 3`v o`o ~ () 26 Grades to with cobbles, occasional boulders 3 4 SA Notes: See Figwe A-1 far explanation of symbols. The depths on the test pit logs are based ov an average of measurements across the mst pi[ and should be considered accwa[e m 0.5 foot LOG OF TEST PIT 3 Project: Proposed Yelm Townhomes Development GEOENGINEERS~ Project Location: Yelm,Washington Project Number: 15252-001-00 Figure A-4 Sheetl ofl Date Excavated: 04/11/06 Logged by: DCR Equipment: Case E#endahoe Backhoe Surtace Elevation (ft)' 341 ' i MATERIAL DESCRIPTION OTHER TESTS ~ t AND NOTES ~_ n... x m t _ a° ~v W~ p~ E E m° 'oE 'oo in in (0~ ern ~U 0 0 4 inches turf, orgama, sod SW-SM Dark brown fine to worse savd with si15 wbbles and gravel, occasional organics, c1aY Pipe fragments (dense, moist) (fill) 340 I Gw Light brown fine to coarse gavel with sand, cobbles, occazional boulders, ° ~° tram sill (dens4 moisQ v D O ° O° D O ° ~° o O ° s ~ O °~ 2 3 335 O ° Q° o O p° o D O ° ~° O po o D O ° ~° ~ o D O p° t 0 Test pit vomPlUed az 10 ket on 04/11/06 No growdwetcr seepage observed No caving observed 330 Notes: See Figure A-l for explanation of symbols. The depths on the test pit lags are hazed ov an average ofineasurements across [he test pit and should be wvsidereA accurate to 0.5 foot. LOG OF TEST PIT 4 Project: Proposetl Yelm Townhomes Development GEOENGINEER~ Project Location: Yelm,Washington Project Number: 15252-001-OD Figure A-5 Sheet 1 of 1 Date Excavated: 04/11/06 Logged by: DCR Equipment Case Extendahoe Backhoe Surface Elevation (ft)' 341 z MATERIAL DESCRIPTION °~ OTHER TESTS a . AND NOTES i.. n_ v a m v m u t ao ev ~-. N N U' J U' (9 E U a - flinches turf, orgvtics, sod SP-3M Dark brown fine to warse seed with si1S cobbles, gavel and occasional orgenica (dense, moirt) 340 1 - - Gw Light browv fine to coarse gavel with sand, wbbles and occasional ° ~° bodders, trace sot (dense, moist) D O ° p° e O ~ °~° 5 SA 5 O ° Q° o D O 335 ° Q° _ o O ° ~° o D O p° c O ~° o Q l ° ~° o D O p° 00 t 0 Test pi[ completed az 70 fee[ on 04/11/06 No goundwater seepage observed Moderaze caving observed at 9 feet 330 Notes: See Figwe A-1 for explanazion of symbols. The depths on the test pil logs are based on an average ofineaswements across Ne test pit avd should be considered accwate to 0.5 foot. LOG OF TEST PIT 5 Project: Proposed Yelm Townhomes Development G EO E N GI N E E R5~ Project Location: Yelm, Washington Figure A-s Project Number: 15252-001-00 Sheet t of 1 Date Excavated: 04/11/06 Logged by: DCR Equipment: Cue Extendahoe Backhoe Surface Elevation (ft)' 342 z MATERIAL DESCRIPTION orHERTESrs m ~ m m AND NOTES ~jF p m E E iom 'oE ~_ N. vl ICJ U' VI EU e _ S D flinches turf, organics, sod SM Dark browv silty Eme m coazse sand, wid[ cobbles, gavel and organics (dense, moist) 3a0 _ GW Light broom fore to warse gavel with sand cobbles and occazional ° O° , boulders, trace silt (dense, wet) oOD °O° p O ° O° 6 Op - °O° a op O° Op ° O' 335 p ° O° Op ° O° op ° ~° oOD ° O' 3 o D t e Test pi[ oompleted et 10 feet on 04/1 t/06 No groundwater seepage observed No caving observed -330 Notes: See Figure A-1 for exploration of symbols. The depths on [he test pit logs are based on an average otmeasurements across the test pi[ and should be considered accwa[e [o 0.5 foot. LOG OF TEST PIT 6 Project: Proposed Yelm Townhomes Development GEOENGINEERS~ Project Location: Yelm, Washington Project Number: 15252-001-00 Figure A-7 snP>~ ~ „r t `gi ~~ Date Excavated: 04/11/06 Logged by: DCR Equipment: Case Extendahoe Backhoe Surface Elevation (ft)' 346 z MATERIAL DESCRIPTION S t AND NOTES E E ° ' E ~ w~ O~ m m o o ` w w U~ (7N ~U O _ 5 D 4 inches tw( organms, sod SW-SM Dark brown Lve to coarse sand with si14 cobbles and gavel, occasional organics (devsq moist) 345 I ' GW-GM Lighl browv f e w coarse gravel wiN silt and sand, cobbles and ottazional boWders (dense, moist) 5 340 2 e 3 6 SA t 0 Tes[ pit completed a[ 10 feet on 04/11/06 No groundwa[u seepage observed No caving observed 335 Notes: See Figure A-I for explanation of symbols. The depths on [he test pit logs are hazed ov an average of measurements arsons Ne [es[ pit and shoWd be considered accurate to 0.5 foot. LOG OF TEST PIT 7 Project: Proposed Yelm Townhomes Development GEOENGINEER~ Project Location: Yelm,Washington Project Number: 15252-001-00 Figure A-8 ) Sheen aft >~ 0 o i a o ~ g o _ ~ ~~ ~ 3 ~~u SSfl ~ ~ 5 ~ 0 o < _ 8 ~ _ P L S y 3 3 3 3 5 ">~"> ~ J R ~ o ~ R W j Z J Q - N ~ uu a g _ !/J ~ ~ W ~ ~ o_ Q W Z ° N C z Q ' O V y a ~ ~ ~ ^ O ~ ~ _ \ ~ Ws me U ++ ~ C f O U 2 O K Q O m p~ .-mn 7 X~ m W O 'J V O O E O~O~ O O N O O O O O O O O O O O `-' O m M r O N V M N 1 H ~I 8M A 8 ~ NIS S Vd 1 N3 ~ 213 d GEOENGINEER SIEVE ANALYSIS RESULTS ~ FIGURE A-9 h W GEOENGINEER~ APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE' This appendix provides information to help you manage your risks with respect to the use of [his report GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES, PERSONS AND PROJECTS This report has been prepared for the exclusive use by KPFF Consulting Engineers and their authorized agents. This report may be made available to regulatory agencies for review. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a cons[mction contractor or even another civil engineer or azchitect that aze involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepazed for dte exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third parties with whom there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this azea at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT IS BASED ON A UNIQUE SET OF PROJECT-SPECIFIC FACTORS This report has been prepared for ICPFF Consulting Engineers for fire Proposed Yelm Townhomes Development project located m Yelm, Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, do not rely on this report if it was: • not prepazed for you, • not prepared for your project, • no[ prepared for the specific site explored, or • completed before important project changes were made. For example, changes that can affeo[ the applicability of this report include those that affect: • the function of the proposed structure; • elevation, configuration, location, orientation or weight of the proposed structure; • composition of the design team; or • project ownership. ~ Developed based on material provided by ASFL, Professional Hems Practicing in [he Geosciences; www.asfe.org. File h'o. 15152-001-00 ppge g_ j May I9, 1006 GEOENGINEERS~ If important changes aze made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommeudations and provide written modifications or confvma[ion, as appropriate. SUBSURFACE CONDITIONS CAN CHANGE This geotechnical or geologic report is based on conditions that existed at the time [he study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by namml events such as floods, earthquakes, slope instabiliTy or ground water fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. TOPSOIL For the purposes of [his report, we consider topsoil to consist of generally fine-gained soil with an appreciable amount of organic matter based on visual examination, and to be unsuitable for direct support of the proposed improvements. However, [he organic content and other mineralogical and gradational characteristics used to evaluate the suiffibiliTy of soil for use in landscaping and agricultural purposes was not determined, nor considered in our analyses. Therefore, the information and recommendations in [his report, and our logs and descriptions should no[ be used as a basis for estimating the volume of topsoil available for such purposes. MOST GEOTECHNICAL AND GEOLOGIC FINDINGS ARE PROFESSIONAL OPINIONS Our interpretations of subsurface conditions are based on Feld observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at [hose points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed 5eld and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranTy of the subsurface conditions. GEOTECHNICAL ENGINEERING REPORT RECOMMENDATIONS ARE NOT FINAL Do not over-rely on the preliminary constmction recommendations included in this report. These recommendations are not fmal, because they were developed principally from GeoEngineers' professional judgment and opinion. GeoEngineers' recommendations can be finalized only by observing acme] subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or IiabiliTy for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Reffiining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions. Fite No. 15252-00l-00 page B,2 May 19, 1006 GEOENGINEERS~ A GEOTECHNICAL ENGINEERING OR GEOLOGIC REPORT COULD BE SUBJECT TO MISINTERPRETATION Misinterpretation of this report by other design team members can result in costly problems. You could tower that risk by having GeoEngineers confer with appropriate members of the design team afrer submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnica] engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and precons[mc[ion conferences, and by providing construction observation. DO NOT REDRAW THE EXPLORATION LOGS Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnica) engineering or geologio report should never be redrawn for inclusion in azchi[ec[ural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. GIVE CONTRACTORS A COMPLETE REPORT AND GUIDANCE Same owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contreotors the complete geotechnica) engineering or geologic report, but preface it with a clearly written letter of transmittal. In that Ietteq advise contractors drat the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to wnfer wilt GeoEngineers and/or to conduct additional study to obtain the specific Types of information they need or prefer. A pre- bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a wntingency for unanticipated conditions should be included in your project budget and schedule. CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS Our geotechnica) recommendations are not intended to direct the contractor's procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safeTy and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. READ THESE PROVISIONS CLOSELY Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnica! engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistio expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory "]imitations" provisions in our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these "Report Limitations and Guidelines for Use" apply to your project or site. Fife No. /5152-00/-00 ppge g_3 May 19, 2006 GEOENGINEERS~ GEOTECHNICAL, GEOLOGIC AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or recommendations; e.g, about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regazding a specific project. BIOLOGICAL POLLUTANTS GeoEngineers' Scope of Work specifically excludes the investigation, detection, prevention, or assessment of the presence of Biological Pollutants in or around any structure. Accordingly, this report includes no interpretations, recommendations, findings, or conclusions for the purpose of detecting, preventing, assessing, or abating Biological Po]lutants. The term "Biological Pollutants" includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. File No. 15251-00f-00 Page B-4 May l9, 2006 ~i EOENGINEERS~ Appendix 6 Maintenance Agreement RESIDENTIAL AGREEMENT TO MAINTAIN STORM WATER FACILITIES GMS CONSTRUCTION CORPORATION ITS HEIRS, SUCCESSORS, OR ASSIGNS (HEREINAFTER"DEVELOPER'S AND CITY OF YELM (HEREINAFTER"JURISDICTION") The upkeep and maintenance of stormwater facilities is essential to the protectic¢ of water resources. The DEVELOPER is expected to conduct business in a manner that promotes environmental protection. This Agreement contains specific provisions with respect to maintenance of on site stormwater facilities. LEGAL DESCRIPTION Plat of Yelm Townhomes, Yelm, Thurston County, WA Whereas, the DEVELOPER has constructed improvements, including but not limited to, buildings, pavement, and stormwater facilities on the property described above. In order to further the goals of the JURISDICTION to ensure the protection and enhancement of water resources, the JURISDICTION and the DEVELOPER hereby enters into this Agreement. The responsibilities of each party to this Agreement are identified below. The DEVELOPER shal4 (1) Implement the stormwater facility maintenance program included herein as Attachment "A". The JURISDICTION shall: (1) Provide technical assistance to the DEVELOPER in support of its operation and maintenance activities conducted pursuant to ita maintenance program. Said assistance shall be provided upon request and as JURISDICTION time and resources permit, at no charge to DEVELOPER. (2) Conduct a minimum of one (1) site visit per year to discuss performance and problems with the DEVELOPER. REMEDIES (1) If the JURISDICTION determines that maintenance or repair work is required to be done to the strom water facilities located on the owner/homeowners association property, the JURISDICTION shall give owner/association of the property notice of the specific maintenance and/or repair required. The JURISDICTION shall set a reasonable time in which such work is to be completed by persons who were given notice. If the above required maintenance and/or repair ie mt completed within the time aet by the JURISDICTION, written notice will be sent to persons who were given notice stating the JURISDICTION's intention to perform such maintenance and bill owner/homeowners association for all incurred expenses. The JURISDICTION may also revoke stormwater utility rate credits ff required maintenance is not performed. (2) If at any time the JUE2.ISDICTIO'_V determines that the existing system creates any imminent threat to public health or welfare, the JURISDICTION may take immediate measures to remedy said threat. However the JURISDICTION shall also take reasonable steps to immediately notify either the property owner or the person in control of said property of such imminent threat in order to enable such owner or person in control to take such immediate measures either independently or in cooperation with the JURISDICTION. (3) The DEVELOPER grant limited authority to the JURISDICTION far access to any and all stormwater system features for the purpose of performing maintenance or repair or inspection pursuant to the terms of this agreement. (q) The persons listed in (1), above shall assume responsibility for the coat of maintenance and repairs to the stormwater facility. Such responsibility shall includes reimbursement to the JURISDICTION within 90 days of receipt of an invoice for work performed by the JL'AISDICTION in maintenance or repairing such facility pursuant to the terms of this agreement. Overdue payments will require payment of interest at the current legal rate for liquidated judgments. If legal action ensues, any costs or fees incurred by the JURISDICTION will be borne by the parties responsible for said reimbursements. This Agreement is intended to protect the value and desirability of the real property described above and to benefit all the citizens of the JURISDICTION. It shall run with the land and be binding on all parties having or acquiring any right, title, or interest, or any part thereof, o£real property. They shall insure to the benefit of each present or future successor in interest of said property or any part thereof, or interest therein, and to the benefit of all citizens of the JURISDICTION. IN WITNESS WHEREOF, this instrument has been executed Owner STATE OF WASHINGTON ) COUNTY OF THURSTON ) se I certify that I know or have eatie£actoxy evidence that (is/are) the person(s) who appeared before me and said person(s) acknowledged that (helehe/they) signed this agreement and acknowledged it to be (his/her/their) free and voluntary act for the uses and purposes mentioned in the instrument. Given under my hand and official seal this day of , 200_ Notary Public in and for the State of Washingtoq residing in STATE OF WASHINGTON ) COUNTY OF THURSTON ) My commission expires:. ae On this day and year above personally appeared before me, who executed the foregoing instrument and acknowledge the said instrument to be the free and voluntary act and deed of said Municipal Corporation for the uses and purposes therein mentioned and on oath states he is authorized to execute the said instrument. Given under my hand and official seal this day of 200_. Notary Public in and for the State of Washington, residing in My commission APPROVED AS TO FORM: Appendix 7 Vicinity Map N ~,,~ ; o 9OS Ir N.T.S. I SF, _ T_________ I s ___ _ _ ' Ps, i ! OITY OF YELM o I ___ D ~i SW Berry Valley Rod~d etA 50\~ SY VI ~ 5 5 o<a 5~ o !O tae oa Longmire St SE S~S~Q-o~~o _ __ ___ _____ ____ oo `~ O e rry sq v~ S S, P I y~~ oP~ I ~ o' ' ~ ~o o ~ ~ e +____ o~e_ __________. 5 VICINITY MAP N.T.S. Thurston Geodata Center -Parcel Search Thurston,- ~, GeoData•` Center Data for Parcel No. 21724410200 Zoom Map to Parcel View Assessor's Data for Parcel Owner: GMS CONSTRUCTION CORP Address: PO BOX 422 City: SPANAWAY State: WA, 98387 Parcel No.: 21724410200 Site Address: 304 SE LONGMIRE RD Site City: YELM Site Zip: 98597 Section: s24171 E Legal Description: 24-17-1E 1A NE SE COM NW COR SOLBERG ADD N 52-0-0 W 200E P OB S 37 Usecode: 11 -SINGLE-UNIT Tax Code Area: 170 Taxable: Yes Annual Tax: $629.28 Property Type: RES Total Acres: 1 Land Value: $49,000.00 Building Value: $3,000.00 Total Value: $52,000.00 Current Use: N Exemptions: None Wetlands: Floodzone: Flood of 1999: W nter Flootling of 1996: High Groundwater Flood Hazards: Zoning: Historic Site: Permitting Jurisdiction: Jurisdiction of Influence: Stormwater Rate: No Shooting Zone: Animal Control: Unknown NO Unknown Unknown Unknown R-14, No YELM YELM No No Contact Animal Control (360-458-3244) Page I of 2 http://geomapl.geodata.org/website/cadastra]/cesuitspazcel.asp?pazce1=21724410200 7/10/2006 Thurston Geodata Center -Parcel Search Weed Containment Zone: Steep Slopes: Ground Water Sensitive Areas: DNR Natural Heritage Data: Critical Buffers. Shoreline Management Areas: Waterbody & Wetland Buffers: FEMA Panel No.: Wellhead Protection Area: Area of Groundwater Concern: Elevated Nitrates: Soil Type: Hydric Soil: Watershed: Water Service Area: School District: Elementary School: Middle School: High Schoool: Fire Response District: Medic Response District: Residential Outdoor Burning: Planning Region: Census Tract: Radio or Cell Tower: Airport Zone: No Unknown No Unknown No No No 355 Na No No Spanaway gravelly sandy loam, 0 to 3 % slopes; Spanaway gravelly sandy loam, 3 to 15°/ slopes No NISOUALLY RIVER YELM, CITY OF YELM SOUTHWORTH MILL POND AND YELM YELM YELM Medic 2 Residential Outdoor Burning is banned within the city limits and urban growth areas of Lacey, Olympia, and Tumwater. 2 012410 No No Page 2 of 2 http://geomapl.geodata.org/website/cadastralhesultsparcel.asp?parcel=21724410200 7/10/2006 Thurston County A+ Pazcel Search: 21724410200 Thurston County Assessor Parcel Number: 21724410200 6XU[Aeer~: 3045E LONGMIRE RD Svt/!wm/Aanpe: 24VIE Ovaw: GMS CONSTRUCTION CD0.P 51[c 1.OD ACreS M6ress: PD BOX 4I] $PANAWAY, WA 983BJ TCp XUmEV. 1]B Nelphbxhme: 28M3 Ta>paym GMS CONSTRUCTION CD0.P gcpvry Type 0.ESIOENTIAL M6rm: PO BD%423 Tevbk: YES $PANAWAY, WA 983BJ pRry¢EZV11pXVU: Np0¢ 3tlwd DIrttlR TELM S.D. #2 Legal Oesvlpllpm. z4-llQE lA NE $E COM NW CDR $DLBERG ADD N 52-4-0 W 200E P OB 5 3] Wale Sartc' WELL scvir TYce: SEPrtC Page 1 of 1 Date: 7/10/2006 Tax rear Aam[mem rmr Markel Value Bulltlings Marke[ Value Lantl Maixet Value TOlnl Market Values mpfi mas mas zaps mox m01 mps moa mas zooz 30oa moo g3,ooo z;6oB sz,400 $z,zoo gs,zeo $5,3oB (49,000 $43,150 $39,400 $33,]50 §36,500 $35,500 §53,000 §46,J§0 §91,800 §35,950 §41rJ00 §90,600 Residential Structures Year aWll 193$ FIRpIaRe/WDD]$twv 1 CamhuNOa RAMBLER Xral Type SPACE-HEATER CwetruRlm QYillty LOW-COST Futl Type OIL Rryslml [oMlUpn PoD0. Fwrgallm Type PIERS Xumber olBMrome 2 Eatabr Wall Type WOOD-SIDING full BaW9 I poc6ng Maktlil ASPHALT-SLANG PortWl6rtb Ral6enm square Fapbpe Maln FIn15M1eE Area ]BB me Aa[ea[OES once mmntams orepem recpros D~ apprexlmarely u2uBOO p Is m Tne.amn cee aty far tax pereeae[. mqupn rec mz are epaaoee re lany, me acmracy am nmelmesz of p bllznee eara ¢a~~pt be guar rase. An p rsp r e fry Ma[ reties on mmrmatl0n ootalnee rmm [m[ wees¢e aoez zo a[ m[ or tier own rBk Ne¢ner Tnursmn Coun[y a shat//ae /nOeOwlle ~M Ila~le~reamage or losses masse Oy use of[MS lnlormaOpn. A/l crieiu/lnbrmatlon Office of the Assessor PattlCla Cpstellor Aifesior 2000 Lakerlege Deve SW - Olympia, WA 98502 Cuslome! 3ervke (36D)]86-5610 -Fax (360)T54-2966 - TOD (360p59~3933 https://fortTess.wa.gov/thurstonco/propinfo/propsgl/basic~.asp?pn=21724410200 7/10/2006