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HomeMy WebLinkAboutGeological Assessment and Addendum - BLD Engineering / Geo-tech Reports - 7/26/2006 GEOTECHNICAL TESTING LABORATORY JULY 26,2006 RITA MATSON 1905 VISTA LANE BREMERTON,WA 98312 RE: GEOLOGICAL ASSESSMENT ADDENDUM LETTER 91 NE ADMIRAL DRIVE BELFAIR, WA PARCEL123305400008 N47026.909' W122051.219' I visited the above referenced site to observe the deck addition to the home. The deck support columns should extend to the native soil. The pier supports do not rest on native soil and need to be extended. I have no objection to the construction of the concrete driveway. The runoff from the concrete slab should be collected and directed in such a way as to prevent erosion. Thank you for this opportunity to be of service to you. Respectfully, GEOTECHNICAL TESTING LABORATORY �1 Harold Parks, L.G., L.E.G. Senior Engineering Geologist i>. 1-. .:. &. I NE AM.9,6 ia3NOW 3° �5 Y 10011 Blomberg Street SW,Olympia, WA 98512 1 Phone#: (360) 754-4612 Fax#: (360) 7544848 I dF3 -�. . J36 GEOTECHNICAL TESTING LABORATORY Date Received: 12/7/2006 Project: 91 Admiral Way Sample#: 1269 Client: Rita Maston Sample ID: Gravelly sand Boring#: 06-2987-12 Sieve Size Specifications Source: Native Depth: US mm _ Max Min ASTM D-2487,Unified Soils Classification System 6.00" 150.0 SP,Poorly graded Sand with Gravel 4.00" 100.0 Sample Prepared: Moist:X Manual: 3.00" 75.0 Dry: Mechanical: X 2.50" 63.0 Test Standard: AASHTO T 99: AASHTO T 180: Method 2.00" 50.0 ASTM D 698: ASTM D 1557: X C 1.75" 45.0 Dry Dry 1.50" 37.5 Assumed Sp.Gr. Point Percent Density Density Maximum Optimum 1.25" 31.5 2.65 Number Moisture Ibs/ft' Kgs/m' Dry Density %Moisture 1.00" 25.0 1 4.6% 128.2 2,054 132.1 Ibs/ft' 7.7% 7/8" 22.4 2 6.3% 131.3 2,103 2,116 Kgs/m' 3/4" 19.0 82.9% 3 7.9% 132.1 2,117 5/8" 16.0 4 9.7% 130.4 2,089 1/2" 12.5 3/8" 9.5 1/4" 6.3 Moisture 43i6it�"ationship #4 4.750 50.6% 134.0 #8 2.360 2,141 #10 2.000 2,134 $o • 2,12€ #16 1.180 z,11Y>w #20 0.850 • 2,107 #30 0.600 • 2,09' #40 0.425 a.0 2,08>r #50 0.300 2,07m #60 0.250 2,061 128.0 2,051 #80 0.180 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% #100 0.150 Percent Moisture #140 0.106 ♦ Data Points Zero Air Voids Curve Curve Fit #170 0.090 #200 0.075 Specs: Meets Specs? l es No Specs ASTM D-4718,Correction for Oversize Particles %Retained 3/4" 17.1% %Retained Corrected Density Optimum %Retained Corrected Density Optimum %Gravel:49.4% Dtlo1: 0.939 3/4"Sieve lbs/ft3 Kgs/m3 Moisture 3/4"Sieve lbs/ft' Kgs/m3 Moisture %Sand: 49.8% D(30):2.816 5% 133.4 2,137 7.3% 20% 137.6 2,205 6.3% %Silt&Clay:0.8% D1601: 8.901 10% 134.8 2,159 7.0% 25% 139.1 2,228 5.9% Cc: 0.95 LL: 0.0% 15% 136.2 2,182 6.6% 30% 140.6 2,252 5.5% Co: 9.48 PL:0.0% FM: 5.56 PI:0.0% Copyright Spears Engineering&Technical Services PS,1996.2004 Reported by: KEPT B E ILE Reviewed by: P 77,63 # By . LS pate �7-.5c 10011 Blomberg Street SW, Olympia, WA 98512 Phone#(360) 754-4612 Fax#(360) 754-4848 Z F3 Geotechnical Testing Laboratory Form No.: 0067 Page 1 of 1 10011 Blomberg St SW Field Density Test Report Project: 91 NE Admiral Dr OL.ympia, WA 98512 ASTM D 2922 / D 3017 Date: 12/7/2006 Ph (360) 754-4612 Client: Rita Matson Fax (360) 754-4848 Project Location: Belfair l � Nuclear Gauge #: 8235 o MS: 11117 DS: 28579 Test Mode/ Depth or Percent Wet Dry Proctor Rock Percent Percent Test Location Density Density Correcti Maximum on Density Optimum # Depth Elevation Moisture Ibs/ft3 Ibs/ft3 ID % Ibs/ft3 Moisture Compacted Required 1 1 6" IParkingArea Grade 7.5 138.0 130.6 1269 15 136.2 6.6 95.9 95 2 1 8" 1 Parking Area Grade 10.7 138.2 127.5 1269 0 132.1 7.7 96.5 95 r ASTM D 1557(Modified Proctor) r ASTM D 698 (Standard Proctor) W Native Soils r Imported Fills Type and Number of Earth Moving Units: Reported by: Dale Parks Type and Number of Compaction Units: Number of Passes: Thickness of Lift: Reviewed by: John P. Massett Method of Adding Moisture: I✓ In our opinion,compaction generallymeets specifications as indicated bythe test numbers. In our opinion,compaction does NOT meet specifications as indicated by r the test numbers,and material should be reworked or removed. W Contractor Advised I— Full-time observation I✓ Part-time observation ° Respectfully submitted, GEOTECHNICAL TESTING LAB z � i . , , . John P. Massett Regional Manager : �� ku v► Co jO -Ll 63 Q a� GEOTECHNICAL TESTING LABORATORY Date Received: 12/7/2006 Project: 91 Admiral Way Sample#: 1269 Client: Rita Maston Sample ID: Gravelly sand Boring#: 06-2987-12 Sieve Size Specifications Source: Native Depth: US mm Max Min ASTM D-2487,Unified Soils Classification System 6.00" 150.0 SP,Poorly graded Sand with Gravel 4.00" 100.0 Sample Prepared: Moist:X Manual: 3.00" 75.0 Dry: Mechanical: X 2.50" 63.0 Test Standard: AASHTO T 99: AASHTO T 180: Method 2.00" 50.0 ASTM D 698: ASTM D 1557: X C 1.75" 45.0 Dry Dry 1.50" 37.5 Assumed Sp.Gr. Point Percent Density Density Maximum Optimum 1.25" 31.5 2.65 Number Moisture Ibs/ft' Kgs/m' Dry Density %Moisture 1.00" 25.0 1 4.6% 128.2 2,054 132.1 Ibs/ft' 7.7% 7/8" 22.4 2 6.3% 131.3 2,103 2,116 Kgs/m' 3/4" 19.0 82.9% 3 7.9% 132.1 2,117 5/8" 16.0 4 9.7% 130.4 2,089 1/2" 12.5 3/8" 9.5 --- - - 1/4" 6.3 Moisture$3MW"ationship #4 4.750 . 50.6% 134.0 #8 2.360 2,141 #10 2.000 t 2,13,1 #16 1.180 z,un° #20 0.850 �' ♦ =2,101 #30 0.600 d ♦ 2,0916 #40 0.425 170.0 x 2,0812 #50 0.300 C 2'07O #60 0.250 2,061 128.0 2,051 #80 0.180 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% #100 0.150 Percent Moisture #140 0.106 ♦ Data Points --- - --Zero Air Voids Curve ----- Curve Fit #170 0.090 #200 0.075 Pecs: Meets Specs? Yes No Specs ASTM D-4718,Correction for Oversize Particles %Retained 3/4" 17.1% %Retained Corrected Density Optimum %Retained Corrected Density Optimum %Gravel:49.4% Dt101: 0.939 3/4"Sieve Ibs/ft3 Kgs/m3 Moisture 3/4"Sieve lbs/ft3 Kgs/m3 Moisture %Sand:49.8% Dt3ul: 2.816 5% 133.4 2,137 7.3% 20% 137.6 2,205 6.3% %Silt&Clay: 0.8% Dt601: 8.901 10% 134.8 2,159 7.0% 25% 139.1 2,228 5.9% Cc: 0.95 LL:0.0% 15% 136.2 2,182 6.6% '0% 140.6 2,252 5.5% Cu: 9.48 PL:0.0% FM: 5.56 PI:0.0% Copyright Spears Engineering&Technical Services PS,1996-2004 W� Reported by. Reviewed by: V �� fL,S PARE` pate ,. PJA t 10011 Blomberg Street SW, Olympia, WA 98512 Phone#(360) 754-4612 Fax#(360) 754-4848 GEOTECHNICAL TESTING LABORATORY JULY 26,2006 RITA MATSON 1905 VISTA LANE BREMERTON,WA 98312 RE: GEOLOGICAL ASSESSMENT ADDENDUM LETTER 91 NE ADMIRAL DRIVE BELFAIR, WA PARCEL123305400008 N47026.909' W122°51.219' I visited the above referenced site to observe the deck addition to the home. The deck support columns should extend to the native soil. The pier supports do not rest on native soil and need to be extended. I have no objection to the construction of the concrete driveway. The runoff from the concrete slab should be collected and directed in such a way as to prevent erosion. Thank you for this opportunity to be of service to you. Respectfully, GEOTECHNICAL TESTING LABORATORY r� / 1 Harold Parks, L.G., L.E.G. Senior Engineering Geologist �H E _ ,x - P ,z - PAR Z i 3 �• By _ to 10011 Blomberg Street SW, Olympia, WA 98512 1 Phone#: (360) 754-4612 Fax#: (360) 754-4848 Gpote6nical Testing Laboratory Form No.: 0067 Page 1 of 1 10011 Blomberg St SW Field Density Test Report Project: 91 NE Admiral Dr Olympia, WA 98512 ASTM D 2922 / D 3017 Date: 12/7/2006 Ph (360) 754-4612 Client: Rita Matson Fax (360) 754-4848 Project Location: Belfair Nuclear Gauge #: 8235 MS: 11117 DS: 28579 Test Mode/ Depth or Percent Wet Dry Proctor Rock Percent Percent ID Test Location Density Density Correcti Maximum on Density Optimum # Depth Elevation Moisture Ibs/ft3 Ibs/ft3 0/0Ibs/ft3 Moisture Compacted Required 1 6" Parking Area Grade 7.5 138.0 130.6 1269 15 136.2 6.6 95.9 95 2 8" Parking Area Grade 10.7 138.2 127.5 1269 0 132.1 7.7 96.5 95 r ASTM D 1557(Modified Proctor) ASTM D 698 (Standard Proctor) r Nati\&-, Soils I- Imported Fills Type and Number of Earth Moving Units: Reported by: Dale Parks Type and Number of Compaction Units: Number of Passes: Thickness of Lift: Reviewed by: John P. Massett Method of Adding Moisture: In our opinion,compaction generallymeets specifications as indicated bythe test numbers. In our opinion,compaction does NOT meet specifications as indicated by r" r the test numbers,and material should be reworked or removed. { 170 Contractor Advised r Full-time observation r Part-time obse ti' C Respectfully submitted, GEOTECHNICAL TESTING LAB O i rN John P. Massett Y , Regional Manager - N e 0 t � o a GEOTECHNICAL TESTING LABORATORY JuLY 27, 2005 �� '' RITA MATSON AUG 3 0 2005 1905 VISTA LANE MASON CO UN 7-y BREMERTON, WA 98312 RE: GEOLOGICAL ASSESSMENT ADDENDUM LETTER 91 NE ADMIRAL DRIVE BELFAIR,WA PARCEL123305400008 N47026.909' W 122°51.219' As requested, we are responding to the changes to the proposed building design. The original mobile home design is not possible on the existing building pad. The new design will utilize a daylight basement. The fill material was tested for compaction/density in January 2005,meeting the minimum requirements. The proposed construction is not expected to adversely affect the slope stability of the site. No further investigation is warranted at this time. If there are any changes in the loads, grades, locations, configurations or types of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications,as appropriate. Respectfully, GEOTECHNICAL TESTING LABORATORY Harold Parks, L.G., L.E.G. Senior Engineering Geologist 10011 Blomberg Street SW, Olympia,WA 98512 1 Phone#: (360)754-4612 Fax#: (360) 754-4848 41 � f t 6` iI Y'cl _ > s'FEck buc I BLI> 2c5-00 34 V 1�/ r y � zz $Aid.�I,r�nb • - �'� S��CSC.-�k A Iy+N G �r�o ri? Mob;L wnc.� � �.'qh�- �R S,eYt1Q�t1 91 Hd ,RaL. LA)a'1� C 4 4� 8LD zoos-oo 13G- February 9,2005 Page#1 of 1 1 GEOTECHNICAL TESTING LABORATORY EARL IDDINGS P O Box2755 RECEIVED BELFAIR, WA 98528 APR 13 2005 p 6 W. CEDAR ST. Re: In-Place Density est Report performed on 1/28/05 Project: 81 NE Admiral Dr,Mason County Gentlemen: As requested we performed on-site density testing in accordance with current applicable standards. The results obtained were as follows: Test Test ptm"t Dig MAa10e0 % Pereem percent # teeeti" NkgAvm Deceit! Dew! OPUMOM Cempeeted Required lbs1W lbs/fP MoiAmm 1 Final lift fill area 16.7 109.9 116.1 14.9 94.7 90 2 Final lift fill area 17.2 108.3 116.1 14.9 93.3 90 NOTE: All test conformed to industry standards. If you have any questions concerning the test results,the procedures used, or if we can be of any further assistance please call on us at(360)754-4612. Respectfully Submitted, Geotechnical Testing Lab APPROVED Harold Parks, ' Engineering Geolo ist MASON UILDING INSPECTOR S JEC TO APPROVAL FF I L COPY 10011 Blomberg Street SW,Olympia,WA 98512 Phone#:(360)754-4612 Fax#:(360)754-4848 GEOTECHNICAL TESTING LAB RECEIVED / .. !APR zoQg 426 Date Received: 1/28/2005 Sample ID:Iddings Sieve Size Specifications Sample#: #28A Source: 81 NE Admiral Dr US mm Max Min ASTM D-2487,Unified Soils Classification System 6.00" 150.0 100.0% 0.0°/ SM,Silty Sand 4.00" 100.0 100.0% 0.0°/ Sample Prepared: Moist:X Manual: 3.00" 75.0 100.0% 0.0° Dry: Mechanical:X 2.50" 63.0 100.0% 0.0°/ Test Standard: AASHTO T 99: AASHTO T 180: Method 2.00" 50.0 100.0% 100.0% 0.0°/ ASTM D 698: ASTM D 1557:X B 1.75" 45.0 100.0% 0.0°/ Dry Dry 1.50" 37.5 100.0% 0.0°/ Assumed Sp.Gr. Point Percent Density Density Maximum Optimu 1.25" 31.5 100.0% 0.0°/ 2.60 Number Moisture lbs/ft' gym' Dry Density '/o Moist 1.00" 25.0 100.0% 0.0°/ 1 12.4% 110.3 1,767 116.1 ibs/ft' 14.9'/6 7/8" 22.4 100.0% 0.0 4/ 2 13.6% 114.3 1,831 1,859 ICgslm° 3/4" 19.0 100.0% 100.0% 0.0°/ 3 14.81/o 116.2 1,862 5/8" 16.0 100.0% 0.0° 4 15.9% 115.2 I,846 1/2" 12.5 100.0% 0.0°/ 3/8" 9.5 97.0% 100.0% 0.0°/ 1/4" 6.3 100.0% 0.0°/ Moisture Density Relationship #4 4.750 91.0% 100.0% 0.0°/ 119.0 ---- - ---.------; 7- 1,882 #10 2.000 100.0% 0.0°/ �117.0 -----`-----'---- ----'------'------`----- --- ----'. - - -- - ----- ----- ----- .0% 0.0°/ : i n t�1150 ------�-------------------'------ ------i-----'---- ----- '- - ---- 2 � #20 0.850 100.0% 0.0° 13.0 ---- ---4------%------ ------------------ ------%------%---= --- ----- --- #30 0.600 100.0% 0.0° fir-V�oida- 1 of u1.0 _ - . . ---- . o 1782 �' #40 0425 1000°/ 0.0 a/c V09.0 :---- L............ . #50 0.300 100.0% 0.0°/ A 1,732 #60 0.250 100.0% 0.0°/ Imo ----- ---- ' ,i------ ------l--- #80 0.180 100.0% 0.0°/ 105.0 : : 6% 7% W. 9% 10% 11% 12% 13% 14% 19% 16% 17% 18% 19% 20% #100 0.150 100.0% 0.0°/ Percent Moisture #140 0.106 100.0% 0.0° ♦ Data Points --------Zero Air Voids Curve Curve Fit #170 0.090 100.0% 0.0°/ #200 0.075 16.0% 100.0% 0.0° Pecs: Meets Specs?Yes No Span ASTM D4718,Correction for Oversize Particles %Retained 3/4"0.0% %Retained Corrected Density Optimum %Retained Corrected Density Optimum %Gravel:9.0% D1101: 0.047 3/4"Sieve ibs/ft1 Kgs/mf Moisture 3/4"Sieve Ibs/R1 KphW Moisture %Sand:75.0% D1301: 0.948 5% 117.7 1,896 14.2% 20% 123.1 1,972 12.0% %Silt&Clay: 16.0% D1601: 2.818 10% 119.5 1,914 13.5% 25% 125.0 2,002 11.3% Cc:6.80 LL:0.00/9 15% 121.2 1,942 12.7% 30% 126.9 2,033 10.6% Cu: 60.11 PL:0.0% FM:3.64 PI:0.0% Copyright Spears Engineering&Technical Services PS,1996-2001 Hop r �11a No����II Mom ■ MIS a ���iON ail M, , _M 0 CEO ■fir srgrF°� MASON COUNTY g� Ni o i i PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER y p Shelton,Washington 98584 —4 l' -100 1%4 a° DATE: May 2"d, 2005 3 INTER-DEPARTMENTAL COMMUNICATIONS mrn 10 TO: Chuck McCoy, DCD - Planner Z FROM: Alan A. Tahja, P/W - Co. Hydr. Engr. WO# PLG-05 m = rn SUBJ: Geo-Tech Assessment Review NAME: Matson SFR A 91 NE Admiral Drive . GRD2005-00008 Chuck, The geotechnical assessment prepared for the proposed Earl Idding-Rita Matson Single Family Residence(SFR)to be constructed at 91 NE Admiral Drive,Belfair, in the plat of Beard's Cove, has been received and reviewed by Public Works. The report appears to satisfactorily fulfill County requirements for geotechnical assessment reporting. From the contents of the assessment, I recommend accepting the report as satisfying the County's requirement(s) for stability investigation and geotechnical reporting. Recommendations contained in the assessment should be incorporated into the site's development and made conditions for permit issuance. Adequate Erosion and Sediment(E&S)control features need to be implemented during land disturbing activities to protect neighboring properties and State waters from adverse stormwater runoff impacts. The migration or release of silty water or mud from the applicant's property will be considered a violation of County and State water quality protection regulations. In summary,the geotechnical assessment prepared for the proposed Single Family Residence appears acceptable, and stability issues may be considered to have been adequately investigated and addressed. Please feel free to contact me at County extension 461 if you have any questions regarding these comments, or if you feel any features need further discussion or attention. Sincerely, Al A. Tahja File: H: \WP\GEO\Assessments\Matson-Idding.doc au.iete. !'-I WORK ORDER - PUBLIC WORKS DEPT. M Work order y.. PERMIT A�::` ,,, .�Gvoo� ' R uested Number. -©S !.tr Authorized by,� , h Date: TYPO of Works 1C CHO RGE TO: NAME S Rw AGENCY/COMPANY SILUNG ADDRESS PHONE Pub. Works Person in Cha e: AX (o) Project Time Une: (from-to dates ` `x"" -- �/ Project Sort dale: TO Fkfth Of": °0 e ESTIMATED TOTAL III: COSTeSTIMATE . (o) 123t4 Employe LUS jian TOTAL i it ZZ 2� EaIPME�rr USM IQTAL AV MATERIAL USED: — --�-�� i .......... (F) Actual Cost S BARS: PROD v: DATE Emp1"WNRICED —� S Rate Hours 1i0TAL i EQUIPMENT USED: t�L4 gaff j TO--Tr MATERIAL USED: ---_. TOTAL.ALL (0) BILLED GATE -- INV 1� PAID DATE REC.N �.DDtiU6 //V lATSorV PLANNING RECEIVED "APR 13 2005 426 W. CEDAR s i Geotechnical Assessment 91 NE Admiral Drive Belfair, WA Prepared for Earl Iddings Belfair, WA by Geotechnical Testing Laboratory Olympia, Washington February 24, 2005 GEOTECHNICAL TESTING LABORATORY EARL IDDINGS P.O. Box 2755 BELFAIR,WA 98528 RE: GEOLOGICAL ASSESSMENT 91 NE ADMIRAL DRIVE BELFAIR,WA PARCEL123305400008 N47026.909' W 122°51.219' PURPOSE The objective of the geological assessment is to assess the surface and subsurface conditions prevalent at the subject site according to Mason County Ordinance 17.01.100.E4. The parcel is to be developed with a single-family residence. Currently, the site is vacant. Approximately 8 feet of compacted and tested fill material was placed onsite at the proposed building location. el View Looking North SITE CONDITIONS The subject site is a lot located north of the Hood Canal, approximately 1 mile west of Belfair, Washington, (see attached vicinity map). The site is accessed from Admiral Drive along the western property line. The subject site is located in an area of moderate residential development. From the proposed building location (fill area), the site slopes toward the east and toward the south. The steepest natural slope approaches 38 percent along the road. The fill material was constructed on approximately 15 percent r' slopes. The lot is vegetated with fir trees as well as Scot's _ broom, bracken ferns, thistle, blackberry, sword ferns, and grasses. Rapid stream incision was not identified at the site. Slope instability was not discerned onsite or on adjoining parcels. 10011 Blomberg Street SW, Olympia,WA 98512 1 Phone#: (360) 7544612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY GEOLOGIC CONDITIONS The Soil Survey of Mason County, USDA Soil Conservation Service (1960) has mapped the site soils as an Everett gravelly loamy sand, 5 to 15% slopes (Ee). The Everett soils are described as very deep, somewhat excessively drained soil on terraces and outwash plains formed in the glacial outwash stage of the most recent Fraser glaciation. These Everett soils coarsen with depth. Permeability is rapid (up to 20 inches per hour) with a high rate of water transmission. These soils are typically classified as"Hydrologic Group A" relative to surficial runoff. The water capacity for plants is low. The soils are further characterized as having medium runoff potential and moderate water erosion potential. Shrink-swell potential is described as low due to the low organic content. The Geologic Map of Washington—Northwest Quadrant (2002) has mapped the site geology as advance outwash deposits (Qga) of continental glacial origin. The report reads: Advance outwash — Glaciofluvial sand and gravel and lacustrine clay, silt, and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and me grained, with interlayered coarser sand gravel, and cobbles; locally contains nonglacial sediments and deposits mapped as transitional between glacial and nonglacial. Includes the Colvos and Esperance Sand Members of the Vashon Drift and part of the Vashon Drift undivided. ' Rain Washed Material FrcSh%tatcrial Fill Material r a a 4ky Q GROUNDWATER CONDITIONS Groundwater seepage was not observed at or near the proposed building location. No wetland vegetation was observed at or near the proposed building location. Depth to static groundwater is unknown, but is assumed to be beyond the scope of the proposed single-family residence. DEPTH TO COMPETENT SOIL Typically, dense gravelly loamy sand is found throughout the site. Competent soil can be expected approximately 10 inches below the ground surface. 10011 Blomberg Street SW, Olympia,WA 98512 2 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY RM PAST SLOPE INSTABILITY Near the proposed building location trees were found straight and vertical. No indication of past P P 8 g instability was discerned at the proposed building location or throughout the site. Adjoining parcels display similar signs of stability as the subject site. Roadside slopes stand steeply with little sign of erosion or slumping. ;g. ,,� r , �� irk*•b { �F View Looking South HISTORY OF LANDSLIDE ACTIVITY No historical landsliding was observed during our site investigation onsite or near the subject parcel. At the proposed building location, the slopes are compact and dense. Onsite trees are straight and vertical. The Relative Slope Stability of the Southern Hood Canal Area, Washington, (1977) describes the site area as Class 2. Class 2 is described as: Areas believed to be stable under normal conditions, but may become unstable if disturbed by man's activities, if slope is oversteepened by erosion, or if subjected to strong seismic shaking. Slopes generally steeper than 15 percent, but may be less in some areas of weak geologic materials. Includes areas underlain by: well-drained sand and gravel, mostly on valley sides that lack known slope failures; glacial till with steep slopes; and bedrock. 10011 Blomberg Street SW, Olympia,WA 98512 3 Phone#: (360) 7544612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY POTENTIAL FOR LANDSLIDE ACTIVITY This site has very little potential for landslide activity. Compacted and tested fill material was imported to create a level proposed building location. Since slopes are moderate 0 and the building location relief is less than 10 feet, the _6 potential for landslide activity is not a concern. ' The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback, 5 , Folger, and Niggemann (September 2004) maps the site area J % as having a very low to low liquefaction potential. The Site Class Map of Mason County, Washington by `l Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004) maps the site area as site class r C to D. Site class Cis a very stiff soil or soft rock and site class D is a stiff soil. The Coastal Zone Atlas maps the site as"stable." EROSION A stormwater drainpipe terminates along the southern property line, see photo below left. Sediment (shown below right) was observed across the property line. The impact is minimal. A drain curtain is proposed along the southern property line. i � Drainpipe from Road 10011 Blomberg Street SW, Olympia,WA 98512 4 Phone#: (360)7544612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY RECOMMENDATIONS Site conditions for the proposed development do not warrant a more comprehensive Geotechnical Report. We recommend no further action is needed unless areas of concern are unearthed during construction or damage ensues from vegetation clearing. To minimize erosion and sedimentation, we recommend that underbrush remain for areas outside the building location. We recommend vegetating the slopes of the fill material. The proposed drain curtain will infiltrate stormwater and control sedimentation and erosion. If there are any changes in the loads, grades, locations, configurations or types of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications, as appropriate. Respectfully, v a$ GEOTECHNICAL TESTING LABORATORY .�, Harold Parks, L.G., L.E.G. Senior Engineering Geologist ed Geo�o HAROLD PARKS 10011 Blomberg Street SW, Olympia,WA 98512 5 Phone#: (360) 754-4612 Fax#: (360) 754-4848 11 T �#f +5+' � x>e):1'd•.fy+'-(Y j,�l• .ram f FW rer Olt 10 MW 106 i all