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Home My WebLink AboutGeoTech Report for BLD2009-00183 - BLD Engineering / Geo-tech Reports - 5/14/2004 MASON COUNTY n°u PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER ss N Shelton,Washington 98584 NT Y DATE: Ma) 14 h 2004 INTER-DEPARTMENTAL COMMUNICATIONS TO: Grace Miller,DCD -Planner TO BE KEPT IN THILE FROM: Alan A. Tahja,P/W - Co. Hydr. Engr. WO# PLG-04 /"►i L ..LFILE SUBJ: Geo-Tech Assessment Review NAME: Jenson SFR a,6300 Grapeview Looy BLD2004-00661 Grace, The geotechnical assessment prepared for the proposed Todd Jenson Single Family Residence (SFR)to be constructed near the 6300 block of the Grapeview Loop Road,has been received and reviewed by Public Works. The report appears to satisfactorily address County requirements for geotechnical assessments. The assessment's author indicates that, in his opinion,the proposed development of the property will not cause stability problems for either the subject property or neighboring properties, and that a more detailed investigation(report) is not warranted. From the contents of the report,I recommend accepting the report as satisfying the County's requirement(s)for stability investigation and geotechnical reporting. Recommendations contained in the assessment should Ibe incorporated into the site's development and made conditions for permit issuance. Adequate erosion and sediment control features need to be implemented during land disturbing activities to protect neighboring properties and State waters from adverse stormwater runoff I 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. I In summary,the geotechnical assessment appears acceptable, and the proposed residential development of the property should be allowed to proceed, subject to the engineer's Irecommendations. 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, Z ' lan A. Tahj File: H:\hT\GEO\Reviews\Jenson.doc 1 PLANNING Geotechnical Assessment 6300 Block of Grapeview Loop Road Parcel #122323100060 Mason Coun WA �Y t., Av Prepared for Todd Jenson Auburn, WA by ' Geotechnical Testing Laboratory Olympia, Washington April 23, 2004 GEOTECIINICAL TESTING LABORATORY TODD JENSON 30840 49T'COURT Sourn AUBURN, WA 98001 RE: GEOLOGICAL ASSESSMENT 6300 BLOCK OF GRAPEvlEw Loop ROAD PARCEL 122323100060 N47021.216' W 122°50.077' i PURPOSE The objectives of the geological assessment are to assess the surface and subsurface conditions prevalent at the subject site according to Mason County Ordinance 17.01.100.E4. A single-family residence with a septic system is proposed. 1 1 r c , S GEOLOGIC CONDITIONS The proposed single-family residence will be located at approximately 6300 Grapeview Loop Road in Mason County, s Washington. The site is located approximately 2.0 miles south of Allyn, Washington. The location of the site is shown relative to the surrounding area on the Vicinity Map, shown on Figure 1. Slope angles for the proposed building site are from 10 percent to 20 percent. The lot is gently sloping ' (approximately 18 percent) with southeastern exposure. The site d' is bounded by undeveloped forestland on the north. A residence is to the south. Eberhart's Cove bounds the site on the southeast. ' Grapeview Loop Road borders the site parcel on the west. The lot is mostly vegetated with vegetation common to the Northwest. No surface water was observed at the site during the site . reconnaissance. Rapid stream incision was not discerned at the site. No deep-seated instability was observed at or around the site. 1 10011 Blomberg Street SW, Olympia, WA 98512 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTEcflmcAL TESTING LABORATORY The Soil Survey of Mason County, USDA Soil Conservation Service (1960) has mapped the site soils as an Alderwood gravelly sandy loam, 5 to 15 percent slopes (Ab). The Alderwood soils typically formed from glacial advance outwash. They are described as having good natural surface drainage. Typically, there is no occurrence of a high water table. Internal drainage is described as medium. An erosion hazard may exist if the vegetation is removed; otherwise, the soil has a low erosion hazard in its present condition. Cementation is usually , present. The soils at the site are mapped as Alderwood gravelly sandy loam (Ab). This site does not meet the technical criteria of an erosion hazard area. The Coastal Zone Atlas, Volume 9, Mason County(MA-12) maps the site as Vashon glacial till (Q,t). The till is a tough, dense material of low permeability. It provides excellent foundation support. The site slope stability is described as "stable" at the building site and "intermediate" along the coast. .. °q ' GROUNDWATER CONDITIONS ' No groundwater seepage was observed at the site. No wetland vegetation was observed at the site. Depth to static groundwater is approximately 32 to 40 feet below the ground surface. A well log for the area follows this report. k -" r r _ i' ' 10011 Blomberg Street SW, Olympia, WA 98512 2 Phone#:(360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY DEPTH TO COMPETENT SOIL Typically, dense glacial till is found from 24 inches to over 48 inches below the ground �u surface. The glacial till extends to an approximate depth of 40 feet. PAST SLOPE INSTABILITY Onsite trees were found straight and vertical. Evidence of landslide activity was observed along the coastal bluff. The slump is due to a tree toppling. s HISTORY OF LANDSLIDE ACTIVITY The Relative Slope Stability of the Southern Hood Canal Area, Washington, (1977) describes the site area as Class 1. Class 1 is expressed as, Areas believed to be stable. Slopes generally less than 15 percent, but may be greater locally in areas too small to be shown at the map scale. Largely comprises rolling uplands underlain by very stable material such as young glacial till, mantled ' in places by a thin layer of sandy gravel or other permeable material; also includes flood plains, deltas, alluvial fans, and some beach deposits. Class 1 areas immediately adjacent to steep slopes of class 3 areas may be threatened by ' potential landsliding. Normal, proper engineering practices generally are adequate to insure stability in these areas. POTENTIAL FOR LANDSLIDE ACTIVITY This site has no indication or record of deep-seated instability. Even though the coastal slope exceeds 100 percent,the potential for landslide activity is not a concern for the proposed building location. AA 1 s,J 10011 Blomberg Street SW, Olympia, WA 98512 3 Phone#: (360)7544612 Fax#: (360)754-4848 GEOTECUMCAL TESTING LABORATORY RECOMMENDATIONS There is no evidence of soil erosion anywhere on the site to suggest that the site should be included in the Erosion Hazard Area designation. 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. �5 ' 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. et Wash Respectfully, �.� GEOTECHNICAL TESTING LABORATORY s Q. Harold Parks,L.G., L.E.G. ' - @qt peo% Senior Engineering Geologist ARCILD PA; 1 1 10011 Blomberg Street SW, Olympia, WA 98512 4 Phone#:(360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY 1 VICINITY MAP y �_� /f�• j� � � � �! jet r 1 'F' �. ,�. '�' �` 4 t�' J� dw �_� t l � / , } (:' � ` �• � 1. � .�\� j f � J / 1 i IN ocks lit ✓ t ' f'f �, / f 1 __ �• `% Rocky POI • 1 • 1 � / ! { 1. t f fi r l •�fr 4 BM 1 10011 Blomberg Street SW, Olympia, WA 98512 ' Phone#: (360) 754-4612 Fax#: (360)754-4848 1 File Original and First Copy with ApplLcation No. Department of fcology WATER WELL REPORT Se cond Copy- Owners Copy copy-Drillers Copy XTA= OF WASEMNG"N Pei t No, . .. ............ (1) OWNER: Name .......�,a...P 1014,rf................................ A41dress.-NA2.2. - 3 a I I (2) LOCATION OF WELL: County ngaQn............ - ....................._. ..............3: ....... See__3.2. T-22.-N.. It-A.U.WN. Bearing and distance front Mellon or subdivWon corner I Lot 3. Abuttinn Cronquial_3sL, (3) PROPOSED USE: Domestic 3 Industrial 0 Municipal 13 (10) WELL LOG: irrigation 0 Test Wen El Outer 0 23��=� charart sftd of mate"al and structure,and tu=and nature of the material in each Xtratuat Prastratoc at lance One-Ivv for ff-h chews of tor-ti- (4) TYPE OF WORM Owner'm number of Well FROM TO (if more than one).... .......... JEATZMALL Now Wes al Iffeewd: tws 0 Somd. [3 Topsoil 0 1 Deepened 0 Cable 0 Driven 0 Reconditioned 0 M0tM7 0 -YOU013 13 Hardpan 1 Ig Rrnun --aanri A qr-vF;1 90 (5) DIMENSIONS: Diameter of Well ----------- incise Qn 3 Drilled Depth of-0-1311-110d well......23L--------ft (6) CONSTRUCTION DETAILS: Casing installed: 9 9L3 Diem. from ......Q_.. ft to Threaded 13 ....... DUM.tz .......... 9L to—it. Welded 0 ......___"DIM. ftlom A. to —IL Perforations: Yes[3 No E Type of padorstor used.---..........._......... SIZZof perforgilona ....................... in.by ......................— UL ..................... perforations from.........------.. ft.in ............------91. ....................... perforations trorn .............. ft. to ---JIL ................- Perforations from to......... 9L SCrte0r. YwO N010 Kanutactureea ------ model Me— Diam. _slot size ..............from .............. it.ID Dl&m. ..__......Slot size..........- from Gravel packed: Yes El No(a size Of gravel:.............. Gravel placed ...........ft to Sur"Ce SCSI* Yea[3 No 0 To what depth? ---U—& material used in*eala.P.n_t.Q.n.;L.t..e............ Did any IrUStu Contain Unu=bk -el-f Van C3 no M Type,of water?..._........__....._..-.-Depa of method of Pealing strata Off (7) PUMP: Xmutact%Le s Name....._......._.._._......._____ WATER LEVELS: LanO-aurfsce elevation above numn me level.... .......... Stall .. .. . ft- below UM 1 of well Dat.. 722=K_ Axteafakn Pressure --.................__._.]be,. Per quire 1-h Date Artesian water is controlled by.-...-------(C---------------------- op.valve.ate.) (9) WELL TESTS: Drswdownbelow Is static amount level water level to is.00 lowered Work irtafted_ Was a pump test roads? Yes 0 No 0 It yes.by whom?._....._....._............... Yield: sal./rain.with ft- drawdown after brs. WELL DRILLER'S STATEMENT: This well was drilled under my jurisdiction and this report is true to the beat of my knowledge and belief. Recove,r;,,data (time taken as zero when pump turned off) (Water level we ed from well top to water level) n Time Water Level rime Water LAW& Time Water Level (Parson, am,*"r"corporation) (Type or printl .......................__. ........ ........................ ........ P .O. Box 30, Allyn, IJa. 95524 ..................... AAdrM........................ ...............a.. ------ ............ ... ......... ..... ............... ...... .............. ............................... .............. ......... Date of test ........ ... ..........._12.......... [SUM0d7..AA9 .. 4 Bailer t. JfL......ggl./.dn. It,d,awdown fW_—A._hn- Artesian now------ .........._r.pM. Date._......----------._.........__..--- . Temperature of water............Waa a Chemical analysis made?yes 0 No M E.Jeeme No ..........I...........Date ...... (TJSR ADDITIONAL SIMUTS V NZCZ81"Y) ECY 05D-1 20