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Preliminary Drainage Reportn ~~ n J ~--~ TAH®IVIA TERRA FAIRWAY ~ IVI lJ LTI-FAIVI I LY YELM, WASHINGTON ~l ~J ~-, R u FCFj~ o~jl F~ 6'~~~6 U n r--, u n ~ PRELIMINARY ®RAIIVAGE REP®RT ~., KPFF Consulting Engineers 4200 Sixth Avenue SE, Suite 309 Lacey, WA 98503 October 6, 2006 n L.I rlII ~J `Jl t~ ~"1 v tJ n i L~ `~I U ~1I i PRELIMINARY DRAINAGE REPORT Tahoma Terra Fairway Multi-family Housing Yelm, Washington October 6, 2006 PROJECT INFORMATION Prepared for: TT PH 3-8 LLC Contact: Doug Bloom REVIEWING AGENCY Jurisdiction: Project Number: Project Contact: City of Yelm, Washington 406037.03 James E. Gibson, P E. PROJECT ENGINEER Prepared by: KPFF Consulting Engineers 4200 6th Avenue SE, Ste. 309 Lacey, WA 98503 Tel: (360) 292-7230 Fax: (360) 292-7231 Contact: Clint Pierpoint, Civil Engineer KPFF Project: Flle Number: I:\2006\406032 Tahoma Terra 1-21Fairway Townhomes-406032.03\Project Documents\Pre Drainage Report Tahoma Terra Fairway.doc PROJECT ENGINEERS CERTIFICATION: I hereby certify that this Preliminary Drainage Report and Erosion Control Plan for Tahoma Terra Fairway in Yelm, Washington has been prepared by me or under my supervision and meets the minimum standards of the City of Yelm and normal standards of engineering practice. I understand that the CITY does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities designed by me i rl tJ ~ Table of Contents ~~ ~I LJ PART I -STORM DRAINAGE REPORT ......................................................1 Section 1 -Proposed Project Description .......................................................... .1 r-~ ~ I U Section 2 -Existing Conditions ........................................................................ .2 Section 3 -Infiltration Rates/Soils Report ........................................................ 2 U Section 4 -Wells and Septic Systems ............................................................... 3 Section 5 -Fuel Tanks ........................................................................................ 3 I LJ Section 6 -Sub-Basin Description ...................................................................... 3 Section 7 -Analysis of the 100-Year Flood ......................................................... 3 Section 8 -Aesthetic Considerations for Facilities ........................................... 3 Section 9 -Facility Sizing and Downstream Analysis ...................................... 3 !-1 Section 10- Covenants, Dedications and Easments .......................................... 4 PART II -EROSION CONTROL REPORT .................................................. 4 n tJ Section 1 -Construction Sequence And Procedure ............................................ 4 n I Section 2 -Trapping Sedunent .......................................................................... 4 ~--~ Section 3 -Permanent Erosion Control & Site Restoration .............................. 5 Section 4 - Geotechnical Analysis And Report .................................................. 5 Section 5 -Inspection Sequence .......................................................................... 5 r? Section 6 -Control Of Pollutants Other Than Sediments ............................... 5 f ~ PART III -MAINTENANCE PLAN ................................................................ 6 n f Section 1 -Required Maintenance ......................................................................6 Section 2 -Responsible Organization ............................................................... 11 Section 3 -Vegetation Management Plan ......................................................11 Section 4 -Source Control .............................................................................11 ~ I APPENDICES LJ Appendix 1 Preliminary Storm Drainage Calculations Appendix 2 Preliminary Drainage and TESC Plan r-~ Appendix 3 FEMA Map Appendix 4 Facility Summary Forms tTJ Appendix 5 Soil Evaluation Report Appendix 6 Maintenance Agreement '~ Appendix 7 Vicinity Map I L_1 11 Ii L__J r`1 I U n ~..1 n n U n Past I Storm Drainage Repot rl ~`Oir~, jv..'"Y Twin, H°,f - `'i~.ll';°lftc"~iS~ Lti'."~1'1c~U. i'Cw~~it n J rl PART I -STORM DRAINAGE REPORT SECTION 1 -PROPOSED PROJECT DESCRIPTION Parcel Number: Total Site Area: Address: Zoned: Required Permits: Section, Township, Range: 78640000009 5.04 acres Not yet arraigned Yelm, WA 98597 MPC Building, Grading, Paving, etc. Section 24, Township 17 North, Range 1 East, W.M., Thurston County, WA Site Location The project site is located in Yelm, Washington southwest of the intersection of Longmire Street SE and Durant Street S in Thurston County, Washington. The site is bounded on the east by Tahoma Terra Golf and Country Club. Project Overview n The applicant is proposing to construct 3multi-family residential buildings with a total of 48 units. Each building has a footprint of approximately 8,400 square-feet. The site will be constructed in one phase and well include appropriate erosion control measures as needed, grading, storm drainage improvements and connection to existing underground utilities including water and sanitary sewer. Storm Drainage Improvements: The total site area is 5.04 Acres. Proposed On-site Conditions • 0.58 acres of roof area • 0.27 acres of impervious sidewalk • 1.04 acres of pervious pavement • 3.15 acres of landscaped/undisturbed pervious area `~ Stormwater Treatment/Storage/Infiltration: Lf Stormwater treatment requirements are based on the 1992 edition of the WSDOE Stormwater Management Manual and the Low Impact Development Technical Guidance Manual for Puget Sound. Pervious pavement will be used on this project. Preliminary calculations are provided in Appendix 1. Treatment and storage will occur n through the infiltration through the pervious pavement and engineered base material. J See Appendix 2 for a preliminary pavement cross section. i `mss vllfc~ l °?C"2 ~c:~">,c~ - ~'C~1Ci" ~ _Y ~ _4.';~ ~~, ."~", j ti+; r The Basin: The Basin includes the 5.04 acres of the proposed site and 0.28 acres of offsite area to ~ the east. The offsite area to the east is vegetated with oak trees and native brush as part of Tahoma Terra Golf and Country Club. All surface runoff will be infiltrated through the pervious pavement. U Roof Runoff: Runoff from the roofs will be routed to roof downspout drains that will be integrated into the pervious pavement reservoir base course. SECTION 2 -EXISTING CONDITIONS The project site is bounded on the north, west and south by Thompson Creek and Associated wetlands, as delineated by the Coot Company in March of 2005. The rl project is bounded on the east by Tahoma Terra Golf and Country Club. ~~ Site Topography is slightly sloping with grades between 2% and 7%. A high point ridge/peninsula located centrally on the site lies in an east to west position. Generally ~, the site slopes away to the north, west and south from this ridge. Elevations range from a high of 338 ft. on the described ridge to a low of 330 ft along the northwest property line. Site vegetation consists of patches of uncropped pasture grasses and indigenous brush amongst a medium density deciduous and conifer forest. The east side of the property is identified per the Thurston County GeoData Center as an oak- coniferforest or woodland canopy per DNR and will be protected and preserved by this project. On-site soils are a combination of well-drained Nisqually and Spanaway series {-~ soils formed in glacial outwash. J There are no man-made drains, channels, or swales, within the protect site. ~ The site is located adjacent to Thompson Creek and Associated wetlands and is within L.1 the related buffer. The northern portion of the site is identified as a high ground water flood hazard area per the Thurston County GeoData Center. The site is not identified as a well head protection area or an aquifer sensitive area per the Thurston County GeoData Center, but site conditions dictate that care must be taken to properly treat runoff from the developed site. SECTION 3 -INFILTRATION RATES/SOILS REPORT The National Resource Conservation Service (NRCSS) of Thurston County mapped the on-site soils as a combination of Nisqually loamy fine sand (74) and Spanaway gravelly sandy loam (110). Geotechnical explorations were performed by William Parnell, P.E. Soils Engineer. His report dated 7/10/06 is included m appendix 5. All test pits generally confirmed the NRCSS soil designations. The soils located on the ridge/peninsula consisted of a Spanaway series, while the lower elevation soils immediately adjacent to the wetlands were consistent with a Nisqually designation. A prevalent water table presence requires consideration for all drainage infiltration facility designs. Soil log test pit data indicates that the highest water depth was 62" below existing ground. To ensure the pavement is not saturated by high water levels a minimum of 3 feet will be maintained between the high water level and the bottom of infiltration facility. Design infiltration rates will be dependent upon targeted soils, the C-horizon being the most desirable due to their high permeability rates. The Nisqually series soils adjacent to the wetlands revealed a shallow water table that generally makes these soils unsuitable for drainage facilities. v The recommendation of the soils professionals is to use an infiltration rate of between ~ 6 and 20 inches per hour for C-horizon soils dependent upon location. All soil horizons J had a minimum infiltration rate of 2 inches per hour based on SCS soil survey information. See attached soil evaluation report for more detailed infiltration information. A design infiltration rate of 1 inch per hour will be used for infiltration calculations. SECTION 4 -WELLS AND SEPTIC SYSTEMS ~ The site is undeveloped and has no record of any well or septic systems ever being LI built on-site. Thurston County has no records of existing or abandoned septic systems on adjacent properties within 100 ft of the proposed infiltration facilities. Any septic systems found will be removed in accordance with Thurston County Department of Health Standards. City of Yelm sewer and water will serve the development 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 Yelm Creek Drainage Basin per the Thurston County Comprehensive Map M-4. The proposed development is being treated as a single drainage basin for the purpose of this study. 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. The majority of the property is in zone X. This is an area determined to be outside of the 100-year flood plain. Small portions of the site along the south west property line lie within Zone A. Zone A is area that has not been analyzed in detail but corresponds to the 100-year flood plain. However, local or spot flooding, if it exists, usually is not shown on FEMA flood insurance maps, and especially if the source of flooding is related to logging, u8V8i~NiiiBiit, yr uraincgc iiiuuifiCatiuri5 Si1iGe ilie date of the r(lap. AIthOUgh the Engineer Is alert to the possibility of flooding from such sources, it cannot be warranted that all areas subject to flooding on or down-gradient of the project site are represented on the map. 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. 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, and infiltrated on-site. Since all stormwater well be infiltrated onsite, a downstream analysis was deemed unnecessary. ,~~~~ ,~~.~n~~~it;r~ ~~~~in~~r'~ ~C;=~~~ c, ~~sn SECTION 1 O -COVENANTS, DEDICATIONS AND EASEMENTS Drainage facilities including the pervious pavement will require routine maintenance The home owners associations or their assigned representatives will be responsible for all maintenance. The maintenance manual prepared for the project lists the maintenance requirements. See Part III -Maintenance Plan of this report. Li r-r J n ~ct~cWrS ~:Qv ~l rl ~II ~J ~-, ~--, Past II Erosion C'ont~ol Repot ~ti:?`J~'~~, i Y"a r'~1i=.v'=~ YI"'3?~,.lt;u3"J l.ii iil~'~~ ~'<,`~~0;; I U ~l U U 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. Muddy construction equipment well not be allowed on the base material or the pavement. 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. Install utilities (water, sanitary sewer, power, etc.). 7. Install impervious concrete, curbing, sidewalks and pour building pads. 8. Install pervious asphalt. 9. Landscape and/or seed all disturbed areas. 10 Maintain all erosion control facilities until the entire site is stabilized and silt runoff ceases. Pervious asphalt system shall be installed toward the end of the construction activities to minimize sediment problems. The subgrade can be excavated to within six inches of final grade and grading completed in later stages of the project. SECTION 2 -TRAPPING SEDIMENT Filter fabric fencing will be installed wherever runoff has the potential to impact ..I .........1.... .. .... ~.... TI.... .. V 1 1 1 uvvvllaucalll IcaGiirC@S. i ilia aiiall iliciuue file areas along downstream property lines. During construction, the Contractor will also be required to install filter fabric fencing as needed, and as directed by the Engineer and/or the City of Yelm. Stabilized construction entrances will be installed to prevent vehicles from tracking soil away from the site. 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. Erosion and sediment control shall be strictly controlled during and after construction. Care shall be taken to not track sediment onto pervious pavement. K>~~~ CUn~~lt~r~ c„~,~ ~~r~ ~~~.: ~ ~, ~~~u~ rl i u~~ii;~, i 4C"= t'ct~" a.:,',,3 - - ' !~f c~;tF~~t"w t=".~,;,C~ i n SECTION 3 -PERMANENT EROSION CONTROL & SITE RESTORATION L~J All disturbed areas will be paved, covered with a building, or landscaped with grass, shrubbery or trees per the development plans Special attention shall be given to areas adjacent to pervious pavement surfaces. Any exposed soil shall be mulched, planted, and otherwise stabilized as soon as possible. SECTION 4 - GEOTECHNICAL ANALYSIS AND REPORT t~ ~ See Appendix 5 for a complete soil evaluation report. There are no slopes exceeding I ~ 15- percent, therefore a geotechnical report for slope analysis was deemed U 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 ~ Z ~ 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. 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 r' period) that occurs during construction. L,i 4. The permanent site restoration measures shall be inspected after landscaping is ,~ completed 5. A final 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 rnng4rNi,rr}inn ~nr~rn~ial ~-rr~ 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 iJ 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 n trucks well away from pervious pavement. ~~~~~ ;U~Wc,~t=~-~~ ~~nw° r~~rs r1 r`1 i ~~iul~,~ l vi"~ ^~S~",", :°~' - ~E'~.?~ ,;twa€'~t ~FEear°i?~~ ~i~NCii Ir'"1 U U U ~1 U U '~ L__1 r'1 '~ ~. J J l__1 Past III 1Vlaintenance Plan Ic's'.~~''"~ T,~r"~ ~,~:P'~;tµf - r'3'c;{~; ~ii~."V ~1"^u-1t~,~~~ ~:''e'~GI"~ PART III -MAINTENANCE PLAN SECTION 1 -REQUIRED MAINTENANCE The on-site storm drainage facilities well 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. U ~S ~..1 ~II ~1 ~l ~~,~„-,~ri_~, t~~rt= ~,~n~b.;l~€r~r ~ =~,~f~~~~ C~t~~~r u, 2~?u~ ~I U ~II ~J n` L~ LJ `~ Inspection Period: I U Number of Sheets Attached: n Date Inspected: U Name of Inspector: Inspector's Signature: n '-l rh U ATTACHMENT "A": MAINTENANCE PROGRAM COVER SHEET ~~ i~ ATTACHMENT "A" U ~"1 ~J r~ I U r"t J L~ r--1 J J 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 less (nonpoisonous) more than 20% of the than 5% of the landscaped area (trees landscaped area. and shrubs onl M Safety hazard Any presence of No poisonous vegetation poison ivy or other or insect nests 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 Section. 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. shrubber a facilit . 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 Causes of erosion pets. identified 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 is and weeded to provide infested with weeds. appealing aesthetics. Do not use chemicals to control weeds. A Trees 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 Trees or shrubs that Replant tree, inspecting have been blown down for injury to stem or or knocked over. roots. Replace if severely damaged. u A Trees or shrubs which Place stakes and rubber- are not adequately coated ties around young supported or are trees/shrubs for support. leaning over, causing ex osure 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 Aprll preferred) M =Monthly (see schedule) Q =Quarterly S =After mayor storms r' I1 U Maintenance Checklist for Pervious Asphalt Pavement Frequency Drainage Req'd Problem Conditions to Check For Conditions That System and actions to take Should Exist Feature M,S Pervious Sediment Ensure that the pervious Sediment is removed Pavement Buildup on pavement surface is free and/or pavement is surface of sediment cleaned so that infiltration works accordin to desi n M,S Pervious Sediment Ensure that the Sediment is removed Pavement Buildup on contributing and adjacent and/or pavement is Surface landscape areas are cleaned so that stabilized and mowed infiltration works with ch in s removed accordin to desi n Q Pervious Sediment Vacuum sweep porous Sediment is removed (4 times/yr Pavement buildup on pavement surface followed and/or pavement is minimum) surface/ by high pressure hosing to cleaned so that preventive keep pores free of infiltration works maintenance sediment accordin to desi n Upon Pervious Spot Clogging Prolonged spot ponding on No prolonged ponding. Failure Pavement pavement surface. Drill Infiltration works half-inch holes through according to design. pavement every few feet. If you are unsure whether a problem exists, please contact the CITY and ask for technical assistance. Comments: ~.-~ Key: A =Annual (March or April preferred) M =Monthly (see schedule) Q =Quarterly S =After major storms v ~a?i!C(i c"i I r?C.'2 `e~: ~ "C~€€';"i€'€c;i;'a' ~'I''ii~~~u ~~ ~~~ SECTION 2 -RESPONSIBLE ORGANIZATION The Home Owners Association or its assigned representative 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 and to control sediment distribution. SECTION 4 -SOURCE CONTROL Warning signs shall be posted indicating the nature of the pervious pavement surface and warning against resurfacing the site with conventional pavement or the use of materials which could affect the infiltration capacity of the surface. ~~~~= CAE ~~~at;ra ~r~~n~~r~ - . n n n ~! ~ Appendix 1 Preliminary Storm Drainage Calculations r-, iJ ~} ~J r? r-r ~.~t n u PRELIMINARY DRAINAGE CALCULATIONS The following calculations are based on the requirements contained in the 1992 Washington State Department of Ecology (WSDOE) Stormwater Management Manual for the Puget Sound Basin. DESIGN AND BASIN INFORMATION SUMMARY: Soil Classification SCS Soil Classification: Spanaway (110) Nisqually (74) Hydrologic Group: B Infiltration Rate: 2 inches/hour SCS Runoff Curve Number: (Table III-1.3 WSDOE Storm Manual) Post-developed (Lawns, 75% + grass cover): CN=80 Pervious pavement CN=80 Post-developed (impervious, roofs, pavement) CN=98 Rainfall Design Storms: (WSDOE Isopluvial Maps-App. AIII-1.1 of WSDOE Storm Manual) 6-month storm (64% of 2 yr. Storm) =1.28" 2 yr./24 hour storm =2.0" 10 yr./24 hour storm =3.0" 100 yr./24 hour storm =4.0" Post-Developed Basin Area Summary Tributary Lot Impervious Area sidewalk 0.27 Ac Disturbed Pervious and Undisturbed Pervious rass/landsca in 3.43 Ac Pervious Pavement 1.04 Ac Directly Connected Tr,,;,er~;n~,s Are? roof area n,SR Ac Total 5.32 Ac The Basin summary conservatively assumes that all undisturbed/landscaped area onsite is tributary to the pavement. In reality some undisturbed/landscaped areas will independently infiltrate Stormwater that will not be directed to the pervious pavement. DETAILED CALCULATIONS: Stormwater Treatment: Pervious Pavement will provide the treatment for the Stormwater. StormShed software was used to model the runoff. l~ u J Sizing Calculations: See the following StormShed software modeling peak output for the design storm event: Desi n Storm 24 hour Peak Out ut Q 6-month 0 167 cfs Q 2 r 0 564 cfs Q 10 r 1 321 cfs Q 100 r. 2 200 cfs Pervious Pavement: The 1992 edition of the WSDOE Stormwater Management Manual and the Low Impact Development Technical Guidance Manual (Puget Sound Action Team, 2005) were used to size the base course for the pervious pavement. The calculations were based on the infiltration rate of 2-inches hour suggested by soil professionals after investigation of the site. The WSDOE Manual states that infiltration BMP's shall be designed to completely drain stored runoff within 24 hours following the occurrence of the 6-month, 24 hour design storm and 48 hours following the occurrence of the 100 year, 24 hour design storm. The Darcy's Law approach is used to demonstrate sufficient capacity and drawdown time of the pervious pavement base/reservoir layer. Q=f *i*A, where f= infiltration rate of soil or infiltration media Q= flowrate at which runoff is infiltrated by soil underlying base course i= hydraulic gradient A= surface area of BMP A factor of safety of "two" was applied to the recommended design infiltration rate of 2 in/hr, thus f=2 in/hr * 0.5 = 1 in/hr = 0.042 ft/hr The hydraulic gradient is shown by the equation: 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 impervious layer. For design purposes hydraulic gradient i was set equal to 1, which made discharge independent of stage. L =assume 3 feet According to StormShed the 100-year/24-hour storm event will result in peak volume of 45,138 cf. The design void percentage for base rock is 30%. The pavement area is 1.04 acres = 45,300 sf. At facility base: A=45, 300 sf; Q(a) _ (0.042 * (0+3)/3) * 45, 300 = 1902.6 cf/hr Assuming infiltration rate by bottom area only; 1902.6 cf/hr *24 hrs = 45,662 cf. Thus the pervious pavement and underlying soils will have the capacity to infiltrate 45,662 cf per 24-hour period, which greatly exceeds the 6-month/24-hour event volume of 6,035 cf and exceeds the 100-year/24-hour event volume of 45,138 cf. In the case of an event larger than the 24-hour/100-year storm or if the pervious asphalt fails, excessive runoff will flow to the westerly points of the drive aisles and release to the landscaped area in the wetland buffer. !J The StormShed calculations that follow show that the peak stage for the 100 year event was 0.347'(4.2") above the base of the storage area. Therefore a base course of 4.2" would be adequate for temporary reservoir storage. However a minimum base course of 14" is ~ recommended in order to provide adequate strength to the wearing course and to minimize the risk of asphalt failure due freeze damage or saturation damage of the top course. The designed pavement section includes 14"fractured rock base material lined with geotextile fabric, and 3" pervious asphalt top course. See appendix 2 for a pavement section detail. n+ u n I U r~II ~f n Li STORMSHED REPORT Wednesday, September 20, 2006 LPOOLCOMPUTE [inf pond] SUMMARY using Puls ,~ ~ Start of live storage: 100.0000 ft Event Match Q (cfs) Peak Q (cfs) Peak Stg (ft) Vol (cf) Vol (acft) Time to Empty ~ _.__ ._,. __._~ __~_.___ w . ~ ___.._._.__ ~, ~.~___~__ W~ _.__..~.__. _ __.. _-___-______ _. ~.. ~....__ 6-month 0.1668 0.1365 100.0130 176.53 0.0041 26.67 2 yr _ 0.5640~~ 0.4663 ~~,~~~100.0444 ~~603.15 0.0138 _ 27.00 ~ , 10 WyrT ^ ...____ 1.3206 1.0507 , l 00.1072 1457.36 „ ~_ 27.17~ 0.0335 µ ~ __ _ 100 yr 2.1997 ? 1.0555 100.3465 4709.45 m ~ 0.1081 27.33 Running I:\\2006\\406032 Tahoma Terra 1-2\\Fairway Townhomes- 406032.03\1Engineer\\inf pond Report.pgm on Wednesday, Se ptember 20, 2006 Summary Report of all Detention Pond Data Event Precip (in) r-t ..~...___ _______ _. _ _ .___ 6-month 1.2800 2 yr 2.0000 10 yr 3.0000 ~ m ~ 100 yr 4.0000 ~~ BASLIST2 [Total Basin] Using [TYPElA] As [6-month] [Total Basin] Using [TYPElA] As [2 yr] [ T otai Basin] Using ~ T Y PE 1 A] As ~ 10 yr] [Total Basin] Using [TYPElA] As [100 yr] LSTEND ,~ BasinID Event Peak Q Peak T Peak Vol i Area (cfs) (hrs) (ac-cf) ~ (ac) ~ ~Method/Loss ~Raintype ` I Total 6- ~ 0 1668 8 00 0 1386 5 32 ~ . . . . Basin ~ month ~ _ ~~ ,_~~ ~ -- __~____ SBUH/SCS TYPElA ~ ~ . ~ _ _ _ _.~__ ~___ , Total Basin 2 yr 0.5640 8.17 0.3333 ~ 5.32 : SBUH/SCS ,TYPElA Total 10 1 32 ~ = yr . 06 8.00 0.6656 5.32 Basin ~ SBUH/SCS `TYPElA ' ~ ? J Total ~~_ _.._.._____ __________.._______._____~._~..__________.~...____._.._ _ ~______ __~~...._,.______._ Basin 100 yr 2.1997 8.00 1.0362 ~ 5.32 r SBUH/SCS ETYPElA `~ _ _ _ __ ____ BASL ~~ ~ A ~~ NJ „ ~- ____ __ __~_. U IST TYPElA AS 6-month DETAILED [ ~ [ ~ [Total Basin] ,~ LSTEND Record Id: Total Basin _ ___ _~ ~_._~_~ ~ __ ~ Design Method SBUH Rainfall type _ _ ~ TYPElA . _ Hyd Intv _ [ 10.00 min Peaking Factor 484.00 ~~ ___ _ ` __ ~~ ~ Abstraction Coeff ~ 0.20 _ _ ~ ~ Pervious Area (AMC 2) ~ 4.74 ac ~3DCIA ~ 0.58 ac __ Pervious CN ; 81.51 ,DC CN 98.00 ~ !~ ~~ ~ ~~ _ Pervious TC 23.83 min jDC TC ~~ ~~ __._. j 10.00 min L( _ _ _ _ _ Pervious CN Calc ~~ ~~~~ _ ~~~ Description ~~~~~~~~~~~~~ SubArea j Sub cn~ ~ ~~ Open spaces, lawns,parks (>75% grass) 3.43 ac 80.00 ~ n Impervious surfaces (pavements, roofs, etc) 027 ac ? 98.00 ~ ~ ff u ~~ ~ Permeable Pavement ----! 1.04 ac ~ 80.00 : ~ Pervious Composited CN (AMC 2) l 81.03 3 _ ~ _ _ _____.._._ ._~ 3 Pervious TC Calc _~ WType~~~w~m Description N^ ~ Length ~~Slope `,Coeff_ Misc TT ~~, ~ ,Sheet SHEET 100.00 ft 0.50% 0.0500 _. _ _...._ ,~......~ ._.. ____ _ _.. __.~ __..._..____._ ~ M_ 2.10 in 8.74 min _ __.... ._._ ~...,._ Shallow SHALLOW 450.00 ft 0.60% '0.0500 _._ ..._.~ ___r ~.___ 15.08 min Pervious TC 23.83 min :_ M __ _____.~..__ _+ _/.. Directly Connected CN Calc Description ~ ~ ~~ ~ __~... SubArea Sub cn ~ Impervious surfaces (pavements, roofs, etc) ~~ ,1 058 ac i 98~00 ~ ____ _ ~DC Composited CN (AMC 2) ~ ~ ~ ~, 98.00 ___. ~ Directly Connected TC Calc r~~ ~ ~ 3 ~ _..__._ _... _~ yp Description _ Length Slope `` Coeff ~__ ____._.____.~...~_ ___._..~__._._.____~_~__ .... ~~ T Misc mm TT ji Fixed 'None Entered £ _____~_.__,__ __ _ 3t ,10.00 min ~ __._ _____._._ _..~....~~..__.____~ _____._.. _....... _....._~__.....__ _._ Directly Connected TC my ._ ~__ ~_..~.. _. ' ~ 1 O.OOmin ! n U L~ n n n n HYDLIST SUMMARY [6-month ou t] [2 yr out] [10 yr out] [100 yr out] LSTEND HydID Peak Q (cfs) Peak T (hrs) Peak Vol (ac-ft) Cont Area (ac) 6-month out 0.1365 8.50 ~ _ ~~~~ 0.1385 _ 5.3200 2 yr out~~ ~~~~0.4663 ~~ ~~~ _ 8.50 ~~ 0.3333 ~ ~~~~ ~~~~~~~~5.3200~ ~~~ 10 yr out 1.0507 8.50 __,_ ...___. ~~ 0.6656 5.3200 100 yr out ~ 1.0555 ..__ 9.50 1.0362 ~ _ 5.3200 STORLIST [pond] LSTEND Record Id: pond Descrip: infiltration pond Increment 0.10 ft Start El. 100.0000 ft ~Max~El.~ 105.0000 ft Length `226.5000 ft Width 200.0000 ft VOID % 30.0000 3 T DISCHLIST [infiltration] LSTEND Record Id: infiltration Descrip: ~~ ,Multiple Orifice Increment ,0.10 ft Start El. "100.0000 ft Max EL 2105.0000 ft Infiltration rate ;1.0000 in/hr ~WP Multiplier ~ 1.00 _ _~ __.__ Licensed to: KPFF, Inc. -Olympia '-1 ~J i U ,II u n J n n n n ~--~ Appendix 2 Drainage 1-~lan wF ~K . x> , ~ 44 ~Y ' 4' ' ;~ Gh sx. ,,t '~ ' i nn g~^ __ ,< n ~ 3 ~ ' .; ~ ~ II 'o ~i r~ .. ,~ ~ n clo~ly T ~ i,i21 Y~.i~ i .. ~ /`~ QpN Z ; \ U Z k p _ ~ Q~ UO N c ~kls tS .s.li tV pl-6~ n ~Z O " ~ ~ O - .. `^ W > O y ~ 6~ O U L U ~oa .4~>, n s L< ~: e:a n sr } K ~ °~ ~ Z ~ O ~ z ~ O ~ F .: - ~ O O ? O ~ Z - ~5>r ~~sa v ~ ` - ~ S 00 O °[ ~ ~ ° O = ' T Z y Q a~~o~g M, fr ~ z 3 0 ~, ~ •. ~ ~. ~~2) _ r ~ ~ ~ ~ ~ ~ ~ 1 - Z Z Z Z O O ~+ O O € ~ ~~ :~ ~ ~ N ~ b - ~~oo ~o ~ dS ~ ~ ~ ~ ~ ~ O s ,i ~ z ~ I ~y N p ~ I ~ Q ~ I I ' ~ ~ o ~ n ~ _ _ \I~ 3NIl,l1?Bd0?Jd ~ \ \\ ° ° N N w ~ 4 w OW = r ? j~a NOLYKZ a Fmrm °m-Z°~ J Va°O m ~ ZF~Zwwo J ~ ¢rZ H° ¢ ~KwUwT~ ~O mW 0>WKSNmm J F~=~O]aO ~W °Z ~~c~w°°~=rc~w3 °W °?3 soap ~qS~O z~ ~ W N ~~l`~ WITi~~ r~ S°WKJW ~O ". 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Q' W J z 0 ~w~ ~ w = = a°w o~rz z ='!~ Z L ?~ ou=iaQ"~~ ~ ~w m uO >ZU>~°w = _ w ~ F- _~ Oww~j O ~~ uu~~.~~w~--IIm~~w w wi ~~ OC~~wLH ~ FU1 ~~ ~ma~3~ Q O. U1 V z ap= Ow w ~o ~~ nG~~~~ _ °o a~ ~owu~~„u, p ~ 4¢ j ~ z w w w ~ N w ~c < w w w O~ ~~d~~na °wQ =cn _ z- ~c~ z? ~°~'~~_~ uwlo ~Z z po ON~u ~j~~w ~~ F-z °=~ndS ~~ d5~ ma~~ ~~u~ ~°w ~~ Q'n ~c~or'aaz moo' ~u =°Z Fzo~`~~~ a~ z4 Na ~w ~w J¢OF ~"~ wKU d= a~a~moo u~m ~„`w~ ,no w~ooq~G~ Y~ aGo z¢ oa°zo"Z~3 °da „~~~ U Y~~~ Q z w O} Q ; z U 3o~c a~~3~~~ ao moo m v vi J Q W W U z Q ~- z w z O F- U F- Vl Z O U z 0 u C u r sno~ 9a i~o muoid j Q Sao ~N~ C ~~o z ;oo ~~ ~v~ Z 'Q~ O U N J a a G ~ o O O UW ~ d a Z J z ~ U ~ ~ ~ w ~ Ir- ~~ s~ ao Z Z ~ O a F z 0 U O p w j 3 O 5 0 a m ~ < ~ ^j v c o ~' ~ O c n O N N U ~ ~ ~ W p J j c O N ~ ~ I ~ 3 N N _ O U O ~ ~ ~. (n C' ~ ~ D ~ ~ ~ O ~ I Lil S O ~ ~ ~ ~r~ a ~- a- w I U Z ~ o ~~ J O~ O Q W ~ U m I r m m tt) ~ O ~ ~ N ~w°~ •o m ~ ~ N ~ ° < w O < ri `r > ~ ~- v m m o °w rn a 3 w w O ~ J U Z O in w rr_ ~Q c~ U 2, Q u i ava~~~mvn~mco zcosoo-s„»awmol a„u,~o nz-i o~~~i o„~o~lo~ rs oeomvnam I au~ F ~ m °~ L ~ ~ z .., u~ z L ~ o > ~ w ~' ~ N ~ r O ~ ~ O ° J ~ o o Q ~ ~U1 ° ~ N ~ r O Z ~ Z ~ FF Z ~ Z~ Z ~ zm ~ ~ ~ L zUl ~ °w ~ O m~ ~ ~ ~ "~ ~ Ul O wad O~ Z p U U Q 1a- ~ ~ O=F U ~] to ° F- O ~ m U ~ ~O Z Z y ~ Q Q > ~ ~ SS O ~~ W Z Q o r Z ~ ~ K K ~ O ~ ~ ° _ Q c Q _ _ N - ~ _ cv .n v ~n 0 0 00 0 0 0 0 ro 0 0 0 00 0 0 0 0 co 0 0 '-1 U n u ~J rl ~J rl `~ '~l ~.J r, i U Appendix 3 FEMA Map J ~, L~ U L~ U ~1 J n n v riI ~J n ~I `~ v ~ Appendix 4 Facility Summary Foams r-, In u n ~II L~ ~1I u lJ n n THURSTON COUNTY REGION FACILITY SUMMARY FORM Complete one (1) for each facility (detention/retention, coalescing plate filter, etc) on the project site. Attach 8 1/2 x 11 sketch showing location of facility. Proponent's Facility Name orldentifier (e.g., Pond A)... ....:Pervious Pavement Name of Road or Street to Access Facility .... , .... N/A .. ... Hearings Examiner Case Number: ... . ..... .. ... .. ... Development Rev. Project No /Bldg. Permit No :. .. .. . ... ... Parce/Number.~. ............ ............ 78640000009 To be completed by Utility Staff: Utility Facility Number Project Number (num) Parcel Number Status (num, 1ch) 0, 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 - Project Name and Proponent Project Name .. ... .... . ........ . .. . Project DEVELOPER .. .. ... . Project Contact .. .. . . Address .... .. .... .. .. Phone.. .. .... .. ...... .. .. Project Proponent: (if different) ............ . .... Address ................. .. . .. . . ... .. Phone ............... ....... ...... ... .. Project Engineer .... .... ... . .. ... .... .. Firm. .. .... .. .. .. Part 2 - Project Location Section(s) 24 Township 17 Range 1 E, Willamette Meridian Tahoma Terra Fairway Tahoma Terra Doug Bloom P O Box 627, Rainier, WA 98567 (360) 951-7568 Same Same Same Clint Pierpomt KPFF Consulting Engineers 360-292-7230 Part 3 -Type of Permit Application Type of permit (e g., Commercial Bldg ): Residential Bldg Other Permits (circle) ^DOFNV HPA ^COE Wetlands ~ ^FEMA ^Shoreline Mgmt f-l r- --- - -' - NPDES Other ^COE 404 ^DOE Dam Safety ^Floodplain ^Rockery/Retaining Wall ®Grading ~J Other Agencies (Federal, State, Local, etc.) that have had or will review this Drainage Erosion Control Plan: ~I U r1 ~J ~l i c_.J Part 4 -Proposed Protect Description What stream basin is this project ~n (e.g , Percival, Woodland) . .... Yefm Creek U Project Srze, acres... .. ..... .... ....... ... .. . .. 5 04 Ac oning . ... ...... .. . . . .. ....... . .. . On-site. ' ' ' .... MPC ~ i Residential Subdivision: ~J Number of Lots'.......... ... ...... ..... 1 Lot size (average), acres:. ... . rl .. .. u~lding Permit / Commercial:... .. . ... . ... Building Footprint, acres• ............. ... 0 58 Concrete Paving, acres:.. ......... 0 27 Gravel Surface, acres•.... . . ... ~ ..... . Lattice Block Paving, acres::... ... . .. .. . ~ Porous paving, acres ... 1 04 Public Roads (including gravel shoulder), acres :....... `~ .... Private Roads (including gravel shoulder), acres :.......... .. . On-site Impervious Surface Total, acres .............. . .. . 085 ~ •. Part 5 -Pre-Developed Project Site Characteristics ,~ Stream through site, y/n: ......... ... . ............ ....... ....... ..NO ~l .............. . . . DNR Type. ...... ........... ... ................... ......... .. .. . ... N/A ... ~ ~ Type of feature this facility discharges to (i e., lake, stream, intermittent stream, Groundwater pothole, roadside ditch, sheetflow to adjacent private property, etc.): ' Infiltration into ground, y/n :........... . Yes ~ ..... Swa/es, Ravines, y/n ::........... ... .............. No ~J Steep slopes (steeper than 15%) y/n:. .... .......... No . Erosion Hazard, y/n ..... ... .... ......... ......... No ~ 100 yr. F/oodp/a~n, y/n:... ....... .. ... . ... . ..... Yes . Lakes or Wetlands, y/n :............ ...... Yes Seeps/Springs, y/n: ... No Hrgh Groundwater Table, y/n: Yes +~ Wellhead Protection orAqu~fer Sensitive Area, y/n:.... No ~~ ~.,i rl ~._) `~1 I U Part 6 -Facility Description -Pervious Pavement Total Area Tributary to Facility Including Off-site (acres) ~.... .... . 5 32ac " otal On-site Area Tributary to Facility (acres) ......... 5 04 ac ~ ? Design lmperv~ous Area Tributary to Facility (acres) . ........ Desi n Land d A . 0 85 ac g scape rea Tributary to Facility (acres) :. ..... ...... 3 15 ac Design Total Tributary Area to Facility (acres).. ..... .... ... . 5 32 ac rater a one (7) for the type of facility )... .. . . ............. Wet pond detention . ...... .. . . . . . ........ . .... Wet pond water surface area .. ... . . . ...... ... ...... Dry pond detention .. ........ . . r~ ... .. . .. . .. Underground detention ........ . ........... .. ... ... n filtration pond....... . . ...... .. .. ........... .... ry well infiltration .... ....... . . . ................. . Coalescing plate separator ........ . '~ Centrifuge separator ......... ... ....... .... .... . Biofilter ........... ...... . .j ............. Other......... .. (Pervious Pavement 1 ~ Outlet type (Enter a one (7) for each type present) Filter...... .... ..... .............. ............. Oil water separator ..... ....... . ....... ........ . .... angle orifice..... .... . .. ..... .... r-~ .. ......... .. . ultiple orifice.. ......... ... . . . ! ~ ......... . .. ... Weir .. ..... .... ........ ............ ~~""' '"' S dlwa p y ........... ........ ....... ................ Pump(s) ...................... . . '-' ............... Other (Infiltration) ... .. . 1 J Part 7 -Release to Groundwater Design Percolation Rate to Groundwater (if applicable) ..... ... 1 mch/hour rl rt `~I ~J ~{ ~._.1 J U n n ~1 n U `~ ~I U n ~1 ~I ~II ~.J ~ Appendix S Soils Evaluation Report J SOIL EVALUATION REPORT FORM 1: GENERAL SITE INFORMATION PROJECT TITLE: Tahoma Terra Fairway SHEET: 1 OF 1 SCA PROJECT NO.. 04104 DATE: 7/10/06 PREPARED BY: William Parnell, P.E. 1. SITE ADDRESS OR LEGAL DESCRIPTION: Longmire Street SE Yelm, WA 98597 TPN: 78640000009 2. PROJECT DESCRIPTION: Create amulti-family subdivision with all associated roadway, utility and landscaping improvements . 3. SITE DESCRIPTION: The roject it i p s e s undeveloped. Site topography is slightly sloping. A high point ridge/peninsula located centrally on the site lies in an east to t i wes pos tion. Generally the site slopes away to the north, west and south from this ridge. Elevations range from a high of 338 ft on the d . escribed ridge to a low of 330 ft. along the northwestern property line. Site vegetation consists of patches of uncropped pasture grasses and indi b genous rush amongst a medium density deciduous and conifer forest. The project site is bounded by Thompson Creek and associated wetlands to the north, west and south, and by the Tahoma Terra Golf & Country Club to the east. On-site soils are a combination of well-drained Nisqually and Spanawa se i il f y r es so s ormed in glacial outwash. 4. SUMMARY OF SOILS WORK PERFORMED: Nine test pits were excavated by trackhoe to a maximum depth of 168" below existing grade. Soils were inspected by entering and visual) to ing each test pit to a depth of four feet Soils be ond f f . y our eet were inspected by examining backhoe tailings. Soil log test pit data sheets are included in this report. 5. ADDITIONAL SOILS WORK RECOMMENDED: Additional soils work may be necessary, dependent upon site-specific drainage design aramete p rs. 6. FINDINGS: The National Resource Conservation Service (NRSC) of Thurston County mapped the on-site soils as a combination of a Nisqually loamy fine sand (74) and a S ana p way gravelly sandy loam (110). All test pits generally confirmed these designations. The soils located on the ridge/peninsula consisted of a Spanaway series, while the lower elevation soils immediately adjacent to the wetlands were consistent with a Nisqually desi nation W t g . a er table was present in all test pits. 7. RECOMMENDATIONS: The Spanaway soil series is a somewhat excessively drained soil that formed in glacial outwash. Infiltration rates are generally rapid in the substrat il um so s. The substratum soils should be targeted for all drainage infiltration facilities. A prevalent water table presence requires consideration for all drainage infiltratio f ilit d n ac y esigns. Design infiltration rates will be dependent upon targeted soils, the C-horizon soils being the most desirable due to their high permeability rates . The Nisqually soil series is also a somewhat excessively drained soil that formed in glacial outwash. Infiltration rates are generally moderatel id i y rap n the substratum soils. However, test pits in the vicinity of the Nisqually series soils revealed a shallow water table that generally makes these soils unsuit bl a e for drainage infiltration facilities. ~ Dunng construction, care must be taken to prevent erosion of exposed soils. Drainage facility infiltration surfaces must be properly protected from contamination by the fine- rained u h i ,-~ g pper or zon soils and from compaction by site construction activities. Soils not properly protected will cause drainage infiltration facilities to prematurely fail. I hereby certify that I prepared this report, and conducted or supervised the performance of related work. I certify that I am qualified to do this work. I represent my work to be complete an ac t ith cura e w in the bounds of uncertainty inherent to the practice of soils science, and to be suitable for its intended use. r1 J SIGNED: DATE: DRAFT SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway PROJECT NO.: SCA 04104 SHEET: 1 OF 9 PREPARED BY: William Parnell, P.E. DATE: 7/6/06 ~ SOIL LOG: #1 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Nisqually Loamy Fine Sand ~74~ Terrace 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL Sandy Glacial Outwash GROUP: 6• DEPTH OF SEASONAL HW: B Unknown 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: ~! 62" 70" Level ~.l 10. POTENTIAL FOR: EROSION RUNOFF PONDING 11. SOIL STRATA DESCRIPTION: See Following chart Slight Slow Minimal 12. SITE PERCOLATION RATE: See FSP (~ 13. FINDINGS & RECOMMENDATIONS: Light mottles were present at 36" increasing to heavy mottles at 48". Soils were wet at 58" and a static water level was present at 62" below the existing grade. The ,--~ C2 horizon was very hard and extremely manganese stained. U Soils Strata Description Soil Log #1 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO <X> FSP Al 0"- 6" 10YR3/2 LmVFSa <10 < 5 <1 1SBK _ _ _ A2 6"- 23" 10YR4/2 LmFSa <10 - < mf 2-6 2 ~ 3 Mas - ff I A3 23"- 4d^ 1nyo6;3 L~roFSa < 2-6 L~ 76 - <3 Mas F1F - - ff 2-6 C1 44"- 70" 10YR5/1 MSa 2 rrr~~~ < <10 SG M3P _ Cgm2 70"- 96" - >20 - 10YR2/1 Gr with CSa <5 <g7 Mas border (Ttll) Str Str _ _ I~ ~1 ~ DRAFT SOIL EVALUATION REP ORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairw ay PROJECT NO.: SCA 04104 SHEET: 2 OF 9 DATE: 7/6/06 PREPARED BY: William Parnell P E , . . SOIL LOG: #2 LOCATION: As per the attached map. `~ 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3 LAND FORM . : None Nisqually Loamy Fine Sand Ter ~74~ race 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: Sandy Glacial Outwash G ROUP: Unknown B - 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: , 1 LAYER: i ~ 140" Greater Than Bottom Of Hole Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING v 11. SOIL STRATA DESCRIPTION: See Following chart Slight Slow Minimal 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS i~ RECOMMENDATIONS: The C1 horizon was mod t l era e y dense. Moderate mottles were present at 88+", Soils were wet at 136" and a static water level w " ~ as present at 140 existing grade. below the I u Soils Strata Description Soil Log #2 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM ROO Al <X> 0"- 10" 10YR3/2 SaLm <15 < 5 <10 Gr _ FSP A2 _ _ 10"- 34" 10YR4/3 LmFSa <10 _ < mf 2 6 10 Mas _ _ 2 C1 - fm 2-6 J4-- 4y 10YR4/6 MSa <5 a C2 _ <5 Mas ff > 20 49"- 58" 10YR5/6 ExGrCSa <1 > 20 C3 _ <85 SG - - - ff >20 58"- 96" 10YR5/1 ExGr&Cob <1 >40 CSa <80 SG C2D - - ff >20 >40 C4 96"-140" 10YR6/2 GrFSa <5 _ < - 25 SG F1 F- ff 6-20 C2D CS 140"-160" 1 DYR2/1 ExGrM-FSa <5 _ <97 Mas I~ U - Str Str - >20 - DRAFT U ~, ~, ~1 SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway PROJECT NO.: SCA 04104 PREPARED BY: William Parnell, P.E. SOIL LOG: #3 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3, LAS None Spanaway Gravelly Sandy Loam (110) 4. DEPOSITION HISTORY: 5. HYDF"' "" - - GlacialOutwash GROUP: B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS DEPTH: LAYER: 132" Greater Than Bottom Of Hole 10. POTENTIAL FC~R• 6. SHEET: 3 OF 9 DATE: 7/6/06 Terrace PTH OF SEASONAL Unknown 9. MISCELLANEOU Level ~rcvoww I KUNOFF I PONDING 11. SOIL STRATA DESCRIPTION: See Following chart Slight Slow Minimal 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Moderate mottles were present at 73+", Soils were wet at 130" and a static water level was present at 132" below the existing grade. Roots were present to 66". Soils Strata Description Soil Log #3 Horz Depth Color Texture Al 0"- 7" 10YR3/2 SaLm A2 T'- 24" 10YR4/2 GrSaLm Bw1 24"- 48" 10YR4/3 GrSaLm C1 48"- 66" 10YR3/6 GrLmCSa C2 66"- 93" 10YR4/6 ExGrCSa C3 93"-168" 10YR5/1 ExGrM-FSa %CL %ORG CF STR MOT <15 <5 <10 Gr _ <15 - <15 Gr <15 - <25 1SBK - <10 - c30 SG _ <1 - <95 SG C2D <2 - <80 5G C2D DRAFT IND CEM ROO <X> FSP - ff 2.6 2 - - mm 2-6 2 - - mm 2_a 3 - - fm 6-20 >15 - - >20 _ - - - 6-20 _ `-1 v LJ v LJ tJ LJ LJ L~ L~ LJ i LJ SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway PROJECT NO.: SCA 04104 SHEET: 4 OF 9 PREPARED BY: William Parnell, P.E. DATE: 7/6/06 SOIL LOG: #4 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: None 3. LAND FORM: Nisqually Loamy Fine Sand Terrace (74) 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL Sandy Glacial Outwash 6. DEPTH OF SEASONAL HW: GROUP: Unknown B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS DEPTH: 9. MISCELLANEOUS: LAYER: 96^ Level 93„ 10. POTENTIAL FOR: EROSION RUNOFF PONDING Sli ht 11. SOIL STRATA DESCRIPTION: See Following chart g Slow Minimal 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Light mottles were present at 58" increasing to moderate mottles at 66". Heavy seepage was present at 96" below the existing grade. The C4 horizon was very hard and extremely manganese stained. Soils Strata Description Soil Log #4 Horz Al A2 A3 C1 C2 C3 C4 Deoth 0"- 4" 4"- 12" 12"- 41" 41"- 62" 62"- 72" 72"- 93" 93"-133" Color 2.SY3/3 2 5Y4/3 10YR3/3 10YR3/3 10YR4/6 10YR5/1 10YR211 Texture LmVFSa LmVFSa Lm\/FCC LmMSa C-MSa ExGrCSa ExGrSa(Till) %CL <10 <10 '1~ - <7 <2 <1 <5 %ORG CF < 5 <3 _ ~ 3 <3 - <10 - <30 _ <95 _ < 70 STR 1SBK Mas Mas Mas SG SG Mas MOT IND - - - - - - F1F _ C2D _ C2D - M3P Mod- CEM ROO ff - ff - mf - - - - - _ <X> 2-6 2-6 2-6 6-20 >20 >20 _ FSP 2 2 2 _ - Str - DRAFT L~ I LJ LJ J J~ n LJ ~l LJ n u L~ J ~i L~ SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway SHEET: 5 OF 9 PROJECT NO.: SCA 04104 DATE: 7/6/06 PREPARED BY: William Parnell, P.E. SOIL LOG: #5 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Nisqually Loamy Fine Sand Terrace (74) 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: Sandy Glacial Outwash GROUP: Unknown B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Level 69" Greater Than Bottom Of Hole 10. POTENTIAL FOR: EROSION RUNOFF PONDING Slight Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Light mottles were present at 38" increasing to moderate mottles at 43". Static water level was present at 69" below the existing grade. Horz Depth Color Texture Al 0"- 6" 10YR2/1 SaLm A2 6"- 16" 10YR3/2 SaLm A3 16"- 30" 10YR4/2 LmVFSa C1 30"- 50" 10YR3/6 LmFSa C2 50"- 68" 10YR5/1 FSa C3 68"- 98" 10YR5/1 ExGrSa Soils Strata Description Soil Log #5 %CL %ORG CF STR <18 <5 <1 Gr <18 - <1 1SBK <15 - <1 Mas <12 - <1 Mas <5 - <5 SG <3 - <75 SG DR~-FT MOT IND CEM ROO <X> FSP - - - ff 2-6 2 - - - ff 2-6 2 - - - ff 2-6 2 F1 F - - ff 6-20 6 C2D - - - >2p _ C2D - - - >20 - ~l L~ ~II tJ ~J rlI u n nII L~ Horz Al A2 r1 A3 ~ C1 ~ C2 I (~ '~ L__l n ~l L~ n ~l SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway PROJECT NO.: SCA 04104 SHEET: 6 OF 9 PREPARED BY: William Parnell, P.E. DATE: 7/6/06 SOIL LOG: #6 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Nisqually Loamy Fine Sand Terrace (74) 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: Sandy Glacial Outwash GROUP: Unknown B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: 69" Greater Than Bottom Of Hole Level 10. POTENTIAL FOR: EROSION RUNOFF PONDING 11. SOIL STRATA DESCRIPTION: See Following chart Slight Slow Minimal 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Light mottles were present at 35" increasing to moderate mottles at 38". Soils were wet at 60° with moderate seepage occurring at 70"below the existing grade. Soils Strata Description Soil Log #6 Depth Color Texture %CL %ORG CF STR MOT IND 0"- 4" 10YR4/2 Lm CEM ROO <X> FSP <28 < < 5 1 Gr - 4"- 12" 10YR5/3 Lm <28 - - ff 2-6 1 - <1 1SBK - - - ff 12"- 42" 2.5Y5/2 LmMSa <g 2-6 1 _ <5 SG F7 F - - ff >?n 42"- 64" 10YR5/1 VGrCSa <3 _ - <60 SG C2D _ - ff 64"- 79" 10YR5/1 LmMSa <g >20 _ _ < 5 SG M3P - - ff >20 DRAFT ~II ~1 n L~ n L~ L~ L~ !J LJ r `~ L~ ~J n LJ LJ SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway SHEET: 7 OF 9 PROJECT NO.: SCA 04104 DATE: 7/6/06 PREPARED BY: William Parnell, P.E. SOIL LOG: #7 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Spanaway Gravelly Sandy Terrace Loam (110) 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GlacialOutwash GROUP: Unknown B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Level 115" Greater Than Bottom Of Hole 10. POTENTIAL FOR: EROSION RUNOFF PONDING Slight Slow Minima 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Faint mottles were present at 94+" becoming moderate at 98°. Soils were wet at 112" with moderate seepage occurring at 115° below the existing grade. Roots were present to 72". The C4 and C5 horizons were slightly to moderately dense and extremely manganese stained. Horz Depth Color Texture Al 0"- 20" 10YR3/2 SaLm Bw 20"- 26" 10YR4/3 VGrSaLm C1 26"- 42" 10YR3/6 ExGrCSa C2 42"- 63" 10YR6/2 ExGrCSa C3 63"- 96" 10YR4/6 VGrCSa C4 96"-120" 10YR2/1 ExGrSa C5 120"-143" 10YR2/1 Pea Gravel wdh CSa border Soils Strata Description Soil Log #7 %CL %ORG CF STR <18 <5 <3 Gr <18 - <q5 SG <3 - <70 SG <3 - <85 SG <1 - <65 SG <1 - <85 SG <1 - <95 SG DRAFT MOT IND CEM ROO <X> FSP - - - ff 2-6 2 - - - ff 2_6 ~ - - - ff >20 >40 - - - ff >20 >40 F1 F - - ff >20 - C2D - - - >20 - C2D - - - >20 - L~ v n ~lI L_.f LJ n V n v L~ rl ffI LJ I n LJ ~1 v SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION PROJECT TITLE: Tahoma Terra Fairway SHEET: 8 OF 9 PROJECT NO.: SCA 04104 DATE: 7/6/06 PREPARED BY: William Parnell, P.E. SOIL LOG: #8 LOCATION: As per the attached map. 1. TYPES OF TEST DONE: 2. SCS SOILS SERIES: 3. LAND FORM: None Spanaway Gravelly Sandy Terrace Loam (110) 4. DEPOSITION HISTORY: 5. HYDROLOGIC SOIL 6. DEPTH OF SEASONAL HW: GlacialOutwash GROUP: Unknown B 7. CURRENT WATER 8. DEPTH TO IMPERVIOUS 9. MISCELLANEOUS: DEPTH: LAYER: Level 162" Greater Than Bottom Of Hole 10. POTENTIAL FOR: EROSION RUNOFF PONDING Slight Slow Minimal 11. SOIL STRATA DESCRIPTION: See Following chart 12. SITE PERCOLATION RATE: See FSP 13. FINDINGS & RECOMMENDATIONS: Moderate mottles were present at 107+". Moderate seepage " was present at 162 below the existing grade. Roots were present to 42". Soils were extremely manganese stained at 107"+. Soils Strata Description Soil Log #8 Horz Depth Color Texture Al 0"- 18" 10YR211 SaLm A2 18"- 33" 10YR3/2 GrSaLm C1 38"- 64" 10YR4/6 ExGrCSa C2 64"- 73" 10YR5/4 ExGrLmFSa C3 73"-168" 10YR5/1 ExGrCSa %CL %ORG CF STR MOT <18 <5 <10 Gr - <18 - <20 Gr - ~~o - «~ SG - <1 - <90 SG - <10 - <65 Mas - <1 - <95 SG C2D IND CEM ROO <X> FSP - - ff 2-6 2 - - mm 2-6 2 - - fm 2-6 >40 - - ff >20 >40 - - - >20 8 - - - >20 - DRAFT U '`1 v '`l v v n v r--, ,~J ,-, v ~.i ~l L~ L~ '-l L~ L~ i LJ i L~ ~,l ~.i ~, Soils Strata Description Soil Log #9 Horz Depth Color Texture %CL %ORG CF STR MOT IND CEM Al 0"- 12" 10YR3/2 GrSaLm <18 <5 ROO <X> FSP <25 Gr - - - ff 2-6 2 Bw 12"- 26" 10YR4/3 VGrSaLm <18 - <q5 SG - C1 26"- 48" 10YR4/6 ExGrFSa <18 - - fm 2-6 2 C2 48"-108" 10YR5/1 ExGr&Cob <1 - <70 5G _ - - fm >20 >20 CSa - <g5 SG - - ff >20 >40 C3 108"-160" 10YR5/4 Gr with CSa <1 - <95 SG binder C2D - - - >20 - DRAFT SOIL EVALUATION REPORT FORM 2: SOIL LOG INFORMATION n U r1 r1 ~.f U n U ~~ v ~...1 J Abbreviations Textural Class Structure (Texture) (STR) Cobble -Cob Granular - Gr Stoney - St Blocky - Blky Gravelly - Gr Platy - PI Sand - Sa Massive - Mas Loamy - Lm Single Grained - SG Silt - Si Sub-An ular Block - SBK Clayey - CI Coarse - C Ve - V Extremely - Ex Fine - F Medium - M Induration &~ Cementation (IND) (CEM) Weak - Wk Moderate -Mod Strong - Str Grades of Structure Strong - 3 Moderate - 2 Weak - 1 fViottles (NiOT) 1 Letter Abundance Few - F CG~iii~ior~ - C Many - M 1st Number Size Fine - 1 Medium - 2 Coarse - 3 2nd Letter Contrast Faint - F Distinct - D Prominent - P Roots (ROO) 1st Letter Abundance 2nd Letter Size Few - f Fine - f Common - c Medium - m Many - m Coarse - c <X> -Generalized range of infiltration rates from SCS soil survey (<X>) FSP -Estimated Field Saturated Percolation rate based on horizon specific factors. rl t U ~~ n .. .~, ~1~ '_ ~ ~ ~ '~~ ~~- ~® ~ a ° ®° ~~ ~ T r ~. _ r r~ d .,. ,,. ~ - ~ ~ ~ ~ ~ t~ [ ~ f~ :.q17 ~_ -._ _ ~~-.~ .~_ (5.040 acr ~ ° ~. _; ;: _ .~. ~.- --,, I ~ _ ,. .,._. .~ ~ ,N_ , ~ a. _ ~, _,~ _, _~~ - - o ~ o Thompson Creek and , y '- _„ ', /////~~~~~ ~•~~®"'''~~--~ ~ i ~ ° ° associated wetlands as ~ - r, delrneated by the Coot _~- ' t~. ', ~ ~- ~ j ~'ompany in March of 2005. ~ i Q sc ~ ._ _~ _. ~ - __ .~~ _~. ~ ~ ° I ~ D ~_~ , u ,, .~_ ._ .__ ,~_ .~ ~ - __ .. .~ _, ~ - -- - - - - ~, ~J DRA'kN BY DESIGNED BY ~ ace cRS T~ CHECKED BY 0.~PR0 ~lD BY I r . CRS ~ Cons lti E L DAIS u ng nq~neers 420J 6th Avenu:, 9wtc 309 6 /2D06 laccy, Washington 96503 -, S C A L E (360) 292-7230 Far (360) 292-723 VISION i ~ 0 B No 406032 03 I'= 60' a ~1 rIl ~J rl I L.~ J Appendix 6 Maintenance Agreement LJ RESIDENTIAL AGREEMENT TO MAINTAIN STORM WATER FACILITIES GMS CONSTRUCTION CORPORATION ITS HEIRS, SUCCESSORS, OR ASSIGNS (HEREINAFTER "DEVELOPER") ~ AND CITY OF YELM (HEREINAFTER "JURISDICTION") The upkeep and maintenance of stormwater facilities is essential to the protection 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: See Plat of Yelm Townhomes, Yelm, Thurston County, WA Whereas, the DEVELOPER has constructed improvements includin g 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 shall: U (1) Implement the stormwater facility maintenance program included herein as Attachment "A". I ~.J The JURISDICTION shall: +-~ (1) Provide technical assistance to the DEVELOPER in support of its operation and maintenance ~ activities conducted pursuant to its maintenance program. Said assistance shall be provided upon request and as JURISDICTION time and resources permit, at no charge to ,~ DEVELOPER. (L) Conduct a mixumum 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 is not completed within the time set by the JURISDICTION, written notice will be sent to persons who were given notice stating the JURISDICTION's '-1 intention to perform such maintenance and bill owner/homeowners association for all incurred expenses. The JURISDICTION may also revoke stormwater utility rate credits if required maintenance is not performed. '-1 U ~1 n (2) If at any time the JURISDICTION 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 DE VELOPER grant limited authority to the JURISDICTION for 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. (4) The persons listed in (1), above shall assume responsibility for the cost of maintenance and ~ repairs to the stormwater facility. Such responsibility shall includes reimbursement to the LJ JURISDICTION within 90 days of receipt of an invoice for work performed by the JURISDICTION in maintenance or repairing such facility pursuant to the terms of this r~ 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, of 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 n ,2 ~I Owner rl J n STATE OF WASHINGTON ) ss ~ COUNTY OF THURSTON ) ~J I certify that I know or have satisfactory evidence that n (is/are) the person(s) who appeared before me and said person(s) acknowledged that (he/she/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_. rlII ~J Notary Public in and for the State of Washington, residing in My commission expires: ~f J STATE OF WASHINGTON ) ss COUNTY OF THURSTON ) 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 inn Notary Public in and for the State of Washington, residing My commission expire APPROVED AS TO FORM: ~l n u n ~J n r--, `~ ~i rl ~, Appendix 7 Vicinity Map ~, n L~ rl n ~J LJ ~II LJ ' 1 LJ I LJ I L~ n rl rl L~ I \ ~ 93rd Ave SE ~ T ~ -- ._ 3 I I~ m I ~ I p I F I -~ ~~_ 9LP SF IY I - I s~ ~~-_ NT.S s~o I CITY OF YELM ~ i sw sere„ ~,.~~e.. _ _ I TAHO _~~'ERF !/l~t~l~'Y !~~'~p N.T.S. v, D~ to ! ~~ ~ongmire Si SE ~' FAIR SAY - _ ~I~I'ULTI~ FAMILY ~ ~ SITE ~ o ~~~ 51 _~___~ r~ ~~ _ J '„te