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Home My WebLink AboutStormwater Infiltration - GRD Engineering / Geo-Tech Reports - 4/23/2009 c GeoResources, LLC Ph.253-896-1011 5007 Pacific Hwy. E., Suite. 20 Fx.253-896-2633 Fife, Washington 98424 April 23, 2009 Blue Star Trust NE 431 Logyard Road Z:5-"hLcaVrl�l /V V??Xtz _-' Belfair, Washington 98528p(360) 275-0228 Yk-Geotechnical Consultation RECEIVEDstormwater Infiltration NE 431 Logyard Road JAN 23 2`" Belfair, WA 98528 4&'— Parcel No. 123211001000 MASON CO. PLANNING DEPT. Job No: BlueStarTrust.LogyardRd2.L `� zC �� This letter provides engineering recommendations for the infiltration of the collected stormwater runoff at the subject site. The proposed development is located north of Belfair in Mason County, Washington. We understand you propose to develop the site for either public recreational use or a possible long term expansion of the North Mason Fiber Company. We further understand you propose to regrade the site to a lower, flatter configuration. We also understand the proposed stormwater facility will include a series of treatments prior to stormwater entering the proposed infiltration gallery. We visited the site, explored the subsurface soils, and performed infiltration testing on March 31, 2009. We previously explored the subsurface conditions and performed infiltration tests on the parcel east of the site. The parcel is currently undeveloped and bordered by the existing commercial development and railroad tracks on the east, vacant land and an existing large lot single family residence on the south, and partially logged parcels on the north and west. The site is triangular in shape and encompasses 19 acres. The ground surface on the site and surrounding areas generally slopes to the west at inclinations of 5 to 15 percent. A localized southwest to north trending 20 to 24 percent slope was observed across the center of the site. Vegetation of the site consists of young second growth timber with a thick understory of both evergreen and deciduous huckleberry, salal and other native vegetation. The site is mapped by the USDA Natural Resource Conservation Service (NRCS) Web Soil Survey for Mason County as Indianola loamy sand (ib), which is derived from sandy glacial outwash. A copy of the NRCS map is included as Figure 2. During our recent site visit, we observed the excavation of four test pits at selected locations near the lowest elevations on the site, near the west property line. A site plan showing the locations of the test pits and infiltration tests is included as Figure 1. Our test pit explorations encountered 2 to 3 feet of topsoil and loose silty fine sand. Underlying these surficial soils we observed medium dense to dense sandy gravel over dense to very dense fine sand with trace silt. These soils represent recessional outwash deposits that are mapped in the site vicinity. At a depth of 20 feet, in Test Pit TP-3, we observed a dense to very dense gravelly silty sand, characteristic of glacial till. The soils appeared to be consistent across the site where the excavations were observed. The soils encountered in the test pits were logged visually classified per ASTM 2488-90. A Blue Star Trust.Logyard2—Stormwater April 23,2009 description of the classification is included as Figure 3. The Test Pit logs are attached as Figure 4. Representative samples were obtained and submitted for laboratory grain size analysis. Our infiltration tests were completed by excavating additional test pits at the proposed location of the stormwater infiltration facilities. In-situ Failing Head Infiltration Tests were conducted in two of the test pits at the proposed bottom of the infiltration pond. The infiltration tests were completed in accordance with the Washington State Department of Ecology Falling Head Percolation Test Procedure, as adopted by Mason County. A site plan showing the locations of the test pits and infiltration tests is included as Figure 1. The test pit soil logs and infiltration data are included as Figure 4. We completed two infiltration tests following the prescribed soaking criteria. Both of our infiltration test yielded rates of 2 to 3 minutes per inch or 20 to 30 inches per hour. The recommended infiltration rates are based on Table 3.8 in the 2005 Department of Ecology Stormwater Management Manual for Westem Washington (SMMWW). Three of the samples were submitted for grain size analysis. Based on our experience with similar soils and the results of our on-site infiltration tests, we recommend an infiltration rate of 20 inches per hour. Appropriate factors of safety will need to be applied to this recommended value. Copies of the lab tests are attached in Appendix A. A factor of safety of 2 is usually applied to surface grade stormwater systems. A higher factor of safety should be considered for a below grade stormwater system. The bottom of the infiltration system should be located at least 5 feet above any impervious surface (such as the glacial till encountered at 20 feet below the ground surface in Test Pit TP-3).We recommend that we observe the excavation of the infiltration system to verify that suitable soils have been exposed. Suspended solids could clog the underlying soils and reduce the long term infiltration rate for the system. To reduce potential clogging of the infiltration system, the infiltration system should not be connected to the stormwater runoff system until after construction is complete and the site areas are landscaped and paved. Temporary stormwater systems may be utilized throughout construction. These temporary systems should be located away from the permanent location of the infiltration facility. Blue Star Trust.Logyard2-Stormwater April 23, 2009 We appreciate the opportunity to be of service on this project. Should you have need of additional information or services please call. Yours Very Truly, GeoResources, LLC Renee M. Hadley, GIT Staff Geologist of wash . , Gr - 2>�e r .S' fir r' r CI dli�,o g t 222 Sid C-P "NAL,, BRA LEY P,n} U BradP-Btggerstaff, W. Glen Coad, PE Principal Principal RMH:BPB:WGC:rmh DocID:BlueStarTrust.LogyardRd2.L Attachments: Figure t-Site Plan Figure 2-Soil Map Figure 3-USCS Classification Figure 4-Test Pit Logs Appendix A-Laboratory Results r � fi 1 SEDIMENT PgND / ` PHASE 2IF N�EDED EPS7WG R.R. TP- ' 1 1 l cRflss' 11 l ( 1 TP-2"ILTATION FENCE 1 a / 1� 6a SCALE 1" = 200' APPROXIMATE LOCATION AND NUMBER OF TEST PIT TP-1 In Site Plan provided by Apex Engineering dated March 8, 2005 GeoResources, PLC Site Plan & Exploration Map 5007 Pacific Highway East, Suite 20 North Mason Fiber Company Fife, Washington 98424 XXX Logyard Roar! Phone: 253-896-1011 Belfair, Washington Fax: 253-896-2633 DocID: BlueStar.Loovard2_SP_ I Anril 70n.c) 1 Fiauro 1 , e � A w _ f � A 4 e 's y F-4 Approxiimate Site Location SCS SCS Soil Name Parent Material Slopes Soil Type inpercent) Ab Aldenvood gravelly sandy loam Glacial Till 5 to 15 Ed Everett gravelly loamy sand Glacial Outwash 0 to 5 Ee Everett gravelly loamy sand Glacial Outwash 5 to 15 lb Indianola loamy sand Sandy glacial outwash 0 to 6 'S Yot to Scale GeoResources, LLC MRCS Soils Map 5007 Pacific Highway East, Suite 20 North Mason Fiber Company Fife,Washington 98424 XXX Logyard Road Phone: 253-896-1011 Beltair, Washington Fax: 253-896-2633 DocID:BlueStar.Log yard2.SCS April 2009 Figure 2 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP GROUP NAME SYMBOL GRAVEL CLEAN GW WELL-GRADED GRAVEL,FINE TO COARSE GRAVEL GRAVEL COARSE GP POORLY-GRADED GRAVEL GRAINED More than 50% SOILS Of Coarse Fraction GRAVEL GM SILTY GRAVEL Retained on WITH FINES No.4 Sieve GC CLAYEY GRAVEL More than 50% SAND CLEAN SAND SW WELL-GRADED SAND,FINE TO COARSE SAND Retained on No.200 Sieve SP POORLY-GRADED SAND More than 50% Of Coarse Fraction SAND SM SILTY SAND Passes WITH FINES No.4 Sieve Sc CLAYEY SAND SILT AND CLAY INORGANIC ML SILT FINE C GRAINED L CLAY SOILS Liquid Limit Less than 50 ORGANIC OL ORGANIC SILT,ORGANIC CLAY SILT AND CLAY INORGANIC MH SILT OF HIGH PLASTICITY,ELASTIC SILT More than 50% Passes CH CLAY OF HIGH PLASTICITY,FAT CLAY No.200 Sieve Liquid Limit 50 or more ORGANIC OH ORGANIC CLAY,ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: SOIL MOISTURE MODIFIERS: 1. Field classification is based on visual examination of soil Dry- Absence of moisture,dry to the touch In general accordance with ASTM D24W90. 2. Soli classification using laboratory tests is based on Moist- Damp,but no visible water ASTM D2487-80. Wet- Visible free water or saturated,usually soil is 3. Description of soil density Or consistency are based on obtained from below water table interpretation of blow count data,visual appearance of soils,and or test data GeoResources, LLC SOIL CLASSIFICATION SYSTEM 5007 Pacific Hwy. E, Ste 20 Fife, Washington 98424-2648 Ph. 253-896-1011 Fx. 253-896-2633 FIGURE 3 Test Pit TP-1 Location: NW-corner of Proposed infiltration Gallery Depth (ft) Soil Type Soil Description 0 - -Y4 - Forest Duff, Topsoil 3/4 - 2 SM Reddish brown silty fine SAND(loose to medium dense, moist) 2 - 4 GP* Brown sandy GRAVEL, basal contact slightly mottled (medium dense to dense, moist) 4 - 7 SP Gray fine to medium SAND (medium dense to dense, moist) 7 - 17 SP** Gray fine SAND with laminations and thin slightly mottled pea gravel cross beds,with trace isolated nodules of silt,trace boulder at depth, compacted (dense to very dense, moist) Terminated at 17 feet below ground surface. No caving observed. No groundwater seepage observed. *Grain Size Analysis: Gravel 59.5%, Sand 39.5%, Fines 1.0% *'Grain Size Analysis: Gravel 0.6%, Sand 92.1%, Fines 7.3% Test Pit TP-2 Location: SW-comer of Proposed infiltration Gallery Depth (ft) Soil Type Soil Description 0 - N4 Forest Duff, Topsoil -Y4 - 2 SM Reddish brown silty fine SAND (loose to medium dense, moist) 2 - 4 GP Brown sandy GRAVEL, basal contact slightly mottled (medium dense to dense, moist) 4 - 6 SP Gray fine to medium SAND (medium dense to dense, moist) 6 - 7 Gray fine SAND with distinct laminations and cross-bedding, compacted, trace isolated SP nodules of silt(dense to very dense, moist) Terminated at 7 feet below ground surface. Minor sloughing observed. No groundwater seepage observed. Falling Head Infiltration test at 6 feet: -2.7 to 3 minutes per inch Test Pit TP-3 Location: SE-corner of Proposed infiltration Gallery _ Depth (ft) Soil Type Soil Description 0 - 1 - Forest Duff,Topsoil 1 - 2'/2 SM Reddish brown silty fine SAND (loose to medium dense, moist) 23h - 61h GP Brown sandy GRAVEL, basal contact slightly mottled (medium dense to dense, moist) 61/2 - 8'/2 SP Gray fine to medium SAND (medium dense to dense, moist) 8I/2 - 20 SP** Gray fine SAND with distinct laminations and thin slightly mottled small gravel cross beds, with trace isolated nodules of silt,trace boulder at depth,compacted (dense to very dense, moist) 20 - 24 MUSM/ Dusky red to weak red (10R4/3 to 1 OR 3/2) GRAVEUSILT/SAND, friable-weakly GM cemented (dense to very dense, moist) (Glacial Till? or Silty Advance Outwash?) Terminated at 24 feet below ground surface. Minor Sidewall caving observed once left open. No groundwater seepage observed. **Grain Size Analysis: Gravel 3.5%, Sand 91.3%, Fines 5.2% Logged by: Renee M.Hadley Excavated on:March 31,20M GeoResources, LLC Test Pit Logs 5007 Pacific Highway East, Suite 20 Proposed Stormwater Gallery North Mason Fiber Co./Blue Star Trust Phone: 253-896-1011 e, Washington 98424 NE 431 Lo9Y and Road Beltair Area Fax: 253-896-2633 Mason County, Washington JOB#Blu9StarTrusLLogyard2.TP I April 2009 Figure 4a Test Pit TP-4 Location: NE- corner of Proposed infiltration Gallery Depth ft Soil Type Soil Description 0 - 1 Forest Duff,Topsoil 1 - 3 SM Reddish brown silty fine SAND (loose to medium dense, moist) 3 6 GP Brown sandy GRAVEL, basal contact slightly mottled (medium dense to dense, moist) 6 11 SP Gray fine to medium SAND with distinct laminations and cross-bedding, compacted, trace isolated nodules of silt(dense to very dense, moist) Terminated at 11 feet below ground surface. Minor sloughing observed. No groundwater seepage observed. Falling Head Infiltration test at 11 feet: --2 to 2.2 minutes per inch Logged by: Renee M. Hadley Excavated on: March 31,2009 GeoResources, LLC Test Pit Logs 5007 Pacific Highway East, Suite 20 Proposed Stormwater Gallery Fife, Washington 98424 North Mason Fiber Co. /Blue Star Trust Phone: 253-896-1011 NE 431 Logyard Road, Belfair Area Fax: 253-896-2633 Mason County, Washington JOB# BlueStarTrusLL.o ard2.TP I Aril 2009 Figure 4b GeoResources, LLC Ph. 253-896-1011 5007 Pacific Hwy. E,Suite 20 Fx. 253-896-2633 Fife, Washington 98424 j APPENDIX "A" I I Particle Size Distribution Report c c .1 100 0 � 10 I I I I I I I I I I I I I 80 20 I I I I I I I I I I I I I 70 30 LU I I I I l i I I I I I II I ao LL I I I I I I I I I I I I I I m 5° I I i i l 1 1 I I I I I I I z Z I I 1 1 1 1 1 I I I I I ! I �0 0 w o I I I I I I I I i I I I I I y 40 a 60 I I I I I I I I I I l i i l m I I I I I I I I I I I I I � 70 ! I I I I I I I I I I I I I 20 80 I I I I I I I I I I I I I I I I I I I I I I I I I I I , 10 i 90 ham- 0 ! ! I 100 100 10 1 0.1 0.01 0.001 � -� GRAIN SIZE-mm. %Gravel %Sand %Fines % " 072 Coarse Fine Coarsel Medium Fine Silt Cia > 0.0 22.4 1 37.1 9.4 1 12.0 18.1 1.0 a� - 3 m =r SIEVE PERCENT SPEC.* PASS? Soil Description SIZE FINER PERCENT (X=NO) Fine GRAVEL with sand °c 0 1.5 1g�7,0 Sampled by RMH on 3131109 3 � Tested by RMH on 4/3/09 1.25 93.4 o 0 1 86.1 Atterberg Limits c c .75 77.5 PL= LL= PI= m c .3125 40S.1 Coefficients r m �' D85=24.5410 D60=9.8268 D50=6.8652 CU #10 31.1 D30= 1.701.0 D15=0.3396 D10=0.2646 o v #20 25.3 Cu= 37.14 CC= 1.11 m #40 19.1 #60 9.0 Classification N #100 2.8 1 USCS= GW AASHTO= m #200 1.0 Remarks U N X m m E L CZ •� rA O (no g=ification provided) o Sample No.: 090024 Source of Sample: Date: " ! Location: TP-1 ElevJDepth: 4 feet below COv, GeoResources, LLC Client: North Mason Fiber Co. In a) 0 Project: v Fife, WA Project No: ---- Fi u re Tested By: RMH Checked By: GC a Particle Size Distribution Report 8 g • r. C. p cli 100 p 8 0 I I I I 1 I I I I I I I I 10 i I I I 111 I ( I I I I I I i I I I I I I I I I I I I ao I 20 I I I I I I I I I I I I I 70 30 w I .I ! I I I I I ! ! I I I I x Z 40 LL I 1 I I I I I I I I I I I z i— I I 11 1 I I I I I I I w 50 1 --i I I I I I I I ( ( I I I I I n I I I I I I I I I I I I I 60 Cn ICE 4 33 4o i I 11 1 I I I 1 I I I I I m 30 70 20 80 I I I I I I I I I I ( I I I I I ! I I I ( I I I I N 10 ! 90 0 I 100 10 1 0.1 0.01 0.001 100 _ GRAIN SIZE mm. cis E %Gravel %Sand %Fines O v %- Coarse Fine arse' Medium Fine Sitt Clay 22 0.0 0.0 0.6 0.3 4.6 87.2 7.3 aD c 3 a� t� SIEVE PERCENT SPEC.} PASS? ° Soil Description SIZE FINER PERCENT (X=NO) Fine SAND Sampled by RMH on 3/31/09 .75 100.0 Tested by RMH on 4/2/09 3 0 .3125 99.6 A.. #4 99.4 o 0 #10 99.1 Atterberg Limits c #20 98.7 PL= LL= P1= LD c #40 94.5 Coefficients #100 19.2 D85=0.3581 D60=0.2610 D50=0.2321 Dap=0.1797 D t 5=0.1357 D 10=0.1120 O -a #200 7.3 = 2.33 Cu c C = 1.11 a) W N 0 Classification 4) 2 USCS= AASHTO= > N Remarks X m N m E N I L O (y (no specification provided) - a Sample No.: 090425 Source of Sample: Date: Location: TP-1 ElevJDepth: 10 feet ° Client: North Mason Fiber Co. _>1 GeoResources, LLC a) Q Project: a� Fife WA Project No: Figure Tested By: RMH Checked By: GC Particle Size Distribution Report tl M N C7 k a 7R 9R R ik a! 100 0 I I I I I I I I I I I I 10 I I 1 1 1 I I I I I I I I I 80 20 I I I I I I I I I I I I I 70 30 I I ! I I I I I I I I I I I T w I I I I I ! I I I I I I I rT Z 40 z LL I I I I I I I I I I I I I I rr Z so ! I I I I I I ! I I I I I z w I ! I I I I I ! I I I I I I 50LU r Cr i I I I I I I I I I I I I I a a. 0 60 m I I I I I I I I I I I I I 30 I 70 I I I I I I I I I I I I I I 20 80 I I I I I I I I I I I I I I I I I I I I I I , ) I I I I ai 14 90 ! I I I I a117,11i co 100 10 1 0.1 0.01 0.001 100 m t� •`-' GRAIN SIZE- mm. cC %Gravel %Sand %Fines .. o O 2 k+3 1 Coarse I Fine a Medium Fine Sift Clay 0.0 i 0.0 1 3.5 2.5 1 13.3 75.5 5.2 3 m u SIEVE PERCENT SPEC.' PASS? Soil Descri tion SIZE FINER PERCENT (X=NO) Fine SAND E0 .7500.0 m 3125 19g.2 Sampled by RMH on 3/31/09 3 > Tested by RMH on 4/2/09 #4 96.5 o #10 94.0 Atterberg Limits c E #20 91.3 PL= LL= PI= f. v #40 32. c° #60 32.0 Coefficients � D85=0.5334 D60=0.3357 D50=0.3041 Z CO #100 11.6 D30=0.2433 D15=0.1761 D10=0.1353 o .0 #200 5.2 Cu= 2.48 Cc= 1.30 c Classification m USCS= AASHTO= ro NRemarks X ID w o (no specification provided) o Sample No.: 090023 Source of Sample: Date: r _ Location: TP-3 ElevIDepth: 14 feet 99) GeoResources, LLC Client: North Mason Fiber Co. 0 Project: a� Fife WA Pro ect No: Fi ure Tested By: RMH Checked By: GC 5007 Pacific Hwy E, Ste 20 Fife,WA 98424 253-896-1011 GOoftslourdes 253-896-2633 PROJECT NAME PRQJECT Noj JECT 3 i PAGE � OF CULATED BY CHECKED BY DATE t 11 s,�N � •: 4 00 ate' be ti O w 2 a 123163460300 '' 123164060000 lal *1 •� '`.x+a�t a" +� ..r !��'?" �.'� +1�, it �' �G"i�" �► �.c' .�' �r 2� `"��°'-��+e�,.� +. � 6 ., '23217500080 Ae '' T�y�;��J',,i'�t�`r° � �t►r `.1� � '" - Ak uj 44 123217500050 �. ` u P 1 T23NR1W + ;Pc1 ,x l�• - i y, r� r 060 ' 123217500 123217600040 1, 123212490060 123211300010 r a t- BRICK i+ J �:. t t23212,§0.080- N123211400020 Vt 2321130006012jr All 1 inch = 300 feet E 1 inch = 0.06 miles S - . - ... •. . . t •. 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