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HomeMy WebLinkAboutGEO-Tech Review for BLD2008-00367 - BLD Engineering / Geo-tech Reports - 4/30/2008 ALKAI CONSULTANTS, LLC . Environmental Engineering • Geotechnical Engineering • Wetland Consulting April 30,2008 10147 Mason County Department of Community Development TO BE KEPT IN T H E P.O. Box 279 Shelton,WA 98584 PARCEL FILE Attn: Mr. Wright Geological Assessment Review Permit#BLD 2008-00367 Applicant: Bahr Dear Mr. Wright At your request, ALKAI CONSULTANTS have reviewed a Geological Assessment for the above referenced permit. The report was prepared by Consolidated Engineering. dated May 21,2006. The assessment was signed and stamped by Rolla B. Boughan,PE. (License#000891). An addendum Map Was provided by Steven P. Morta dated 3/28/2008. After reviewing the initial information ALKAI contacted Morta Engineering&Testing. PLLC, Steven P. Morta, PE requesting two additional clarifications and were provided the attached Addendum on April 25,2008. It is ALKAI's opinion that the assessment,with the amendment's,contains the information required in the Mason County Code 8.52.140 Section 5 (D), for a Geological Assessment. ALKAI therefore recommends that Mason County accept the Geological Assessment for the referenced permit. Should you have any questions or concerns, or if we may be of additional assistance, please call our office at (360)613-2407 or contact us by e-mail at Jim@alkai.net. Sincerely, M$ �. �A Donald Balmer,L.G. t '" jesding,E.I.T Senior Hydrogeologist ; gineer used G_ Donald I Balmer W;e og, Attachments: Geo Tech Work Order Geological Assessment Report by: Consolidated Engineering Addendums by: Morta Engineering and Testing, PLLC Mason County Requirements Checklist ,I 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 • (360) 613-2407 • Fax: (360) 613-2408 Project j� ZJd -O� �� ? ALKAI CONSULTANTS 5/2/2008 Mason County Requirements For Geotechnical Assessment Mason County Code 8.52.140 section 5 (D) 1) A discussion of geologic conditions in the general vicinity of the proposed development, with geologic unit designation consistent with terminology used in the Coastal Zone Atlas (Washington Department of Natural Resources, 1980) or in applicable U.S. Geologic Survey maps (See page 2 for examples of maps). Use of soil conservation service soil layer terminology is considered inappropriate for this assessment. 2) A discussion of the groundwater conditions at the site, including the estimated depth to water and the quantity of surface seepage and the upslope geomorphology and location of upland waterbodies and wetlands. 3) The approximate depth to hard or dense competent soil, e.g., glacial till or outwash sand. 4) A discussion of any geomorphic expression of past slope instability (presence of hummocky ground or ground cracks, terraced topography indicative of landslide block movement, bowed or arched trees indicating downslope movement, etc.). 5) A discussion of the history of landslide activity in the vicinity, as available in the Coastal Zone Atlas, the map of"Relative Slope Stability of the Southern Hood Canal Area, Washington" by M. Smith and R.J. Carson, 1977 (More examples listed on page 2) and the landslide records on file with the Mason County Department of Community Development. 6) An opinion on whether the proposed development is within the landslide hazard area or its associated buffer or setback. 7) A recommendation by the preparer whether a geotechnical report should be required to l further evaluate site conditions and the proposed development of the subject property. 8) If the presence of a hazard is determined within three hundred feet of the proposed development, then the area of proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe) on a geologic map/site map. 9) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of existing and proposed development on the site. Project ALKAI CONSULTANTS 5/2/2008 Examples of accepted maps: Geological Map of North Central Mason County, by R.J. Carson, 1976, U.S. Geologic Survey OFR 76-2). Also to be used as applicable are: Geologic map of the Longbranch 7.5-minute quadrangle, Thurston, Pierce, and Mason Counties, Washington, by R.L. Logan, T.J. Walsh, and Michael Polenz. one sheet, scale 1:24,000, 2003; Geologic map of the Squaxin Island 7.5minute quadrangle, Mason and Thurston Counties, Washington, by R.L. Logan, Michael Polenz, T.J. Walsh, and H.W. Schasse. One sheet, scale 1:24,000, 2003; Geologic map of the Shelton 7.5-minute quadrangle, Mason and Thurston Counties, Washington, by H.W. Schasse, R.L. Logan, Michael Polenz, and T.J. Walsh. one sheet, scale 1:24,000, 2003; and the Geologic map of the Summit Lake 7.5-minute quadrangle, Thurston and Mason Counties, Washington, by R.L. Logan and T.J. Walsh. forty-two by thirty-six in. color sheet, scale 1:24,000, 2004. Examples of accepted Landslide maps: Geologic map of the Longbranch 7.5-minute quadrangle, Thurston, Pierce, and Mason Counties, Washington, by R.L. Logan, T.J. Walsh, and Michael Polenz. one sheet, scale 1:24,000, 2003; Geologic map of the Squaxin Island 7.5-minut quadrangle, Mason and Thurston Counties, Washington, by R.L. Logan, Michael Polenz, T.J. Walsh, and H.W. Schasse. One sheet, scale 1:24,000, 2003; Geologic map of the Shelton 7.5-minute quadrangle, Mason and Thurston Counties, Washington, by H.W. Schasse, R.L. Logan, Michael Polenz, and T.J. Walsh. One sheet, scale 1:24,000, 2003; and the Geologic map of the Summit Lake 7.5-minute quadrangle, Thurston and Mason Counties, Washington, by R.L. Logan and T.J. Walsh. forty-two by thirty-six in. color sheet, scale 1:24,000, 2004; I I MASON COUNTY PLANNING GEO TECH WORK ORDER CONSULTANT ALKAI CONSULTANTS, LLC 9465 PROVOST ROAD NW, SUITE 202 SILVERDALE, WA 98383 PERMIT # 7B C-r> 3(o`� APPLICANT. j���-tZ DATE MAILED PLANNER ���}-F=t' AMOUNT BILLED ADDITIONAL COMMENTS "Please fill out the cost of the review and return this form and the report to us with your recommendations. bl April 25, 2008 Page 1 of 1 Morta Engineering & Testing, PLLC To: Alkai Consultants,LLC 9465 Provost Road NW, Suite 202 Silverdale, WA 98383 (360) 613-2407 Attn: Jim Harding Subject: ADDENDUM to Geological Assessment on Single Car Garage Located at 41 E. Garnet Court,Union,WA 98592 1. Discussion of geologic conditions in the general vicinity of the proposed development: The geologic unit for the area is defined as a Qg, i.e., Quaternary sediments, dominantly glacial drift including alluvium per the Geologic Map of Washington and compiled by J. Eric Schuster in 2002. 2. A discussion of the groundwater conditions at the site,including the estimated depth to water and the quantity of surface seepage and the upslope geomorphology and location of upland waterbodies and wetlands: There were no signs of surface seepage or wetland areas within 300' of the proposed building site. An adjacent well log located at the SE 1/4-1/4 NW 1/4 Section 32 of Township 22 North Range 3 West WWM and documented by the Washington State Department of Ecology indicated that the depth to water was between 268 and 280 feet. If you have any questions regarding this Addendum do no hesitate to call me at (360) 289-0958 or toll free at(800) 590-0958. You can also e-mail me at Smorta eAOL.com. Best Regards, Steven P. Morta, P.E. 1018 E.Wishkah St.,Aberdeen,Washington 98520 (360)289-0958 Bus,(360)289-9682 Fax,(800)590-0958 Toll Free Smorta@AOL.com N Sri N cCreavy, Vicinity Map I ' o Road u Dalby Road X 41 East Garnet Court Union,WA 98592 i ' o E `o 8 to �j Landslide Hazard Geotechnical Letts 196'Elevation o — The geological assessment was performed on March 20,2008 and di E active landslide area within 300 feet of the site. As a result a landslide V 0 was required per Mason County Resource Ordinance. Digital color ph � c� N documentation purposes with the owner present. m a N o The proposed garage is too small for a pickup truck but instead will bi storing construction tools. There's a 10 to 15 degree downward slope oCO the diagram to the right. A steel pointed soil probe was used to check a determined that the shaded area to the right needed to be over excava v7 granular material down to a depth of 2-1/2'in 6"loose lifts and compac IC a+cLa V compactor and a minimum of 6 slow passes per lift. Refer to the typici L footing to the right. The services described in this report were prepared under the respord5 cli P.E. Steven P.Morta meets the qualifications contained in Title 18E,S Co U-' N a landslide hazard geological assessment. Steven P.Morta understan Co g Landslide Hazard Ara Chapter 18E.80 and the definitions of the applic4 198'Elevation Chapterl8.25. Individuals under the reponsible charge of Steven P.N a landslide hazard geological assessment,conducted a field investigat ------- records on or in the vicinity of the above referenced site. In my opinior for this project is adquate to meet the requirements of the Department active landslide hazard area exists within 300 feet of the site. If there any questions regarding this landslide hazard geological letter be contacted at(800)590-0958 or by e-mail at Smorta@aol.com. N D PR A A4 1, 3/9 y i0� m a o N P. �N F- 0�,♦ 200'Datum Elevation Q C:��CF' O�WAS11, �` m 02 �T r'i ; --- ----- w o .-C14 .O 30758 �M) m �O RFGISTER� e`� a SS��NAL�'G w ak o e v ca M a _ _ Q_ STgpF MASON COUNTY QS�N °T os°o i PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER Y O N Shelton,Washington 98584 ry N y 184 DATE: June 20`h, 2005 INTER-DEPARTMENTAL COMMUNICATIONS TO: Kell McAboy,DCD -Planner FROM: Alan A. Tahja, P/W- Co. Hydr. Engr. WO# PLG-05 SUBJ: Geo-Tech Assessment Review NAME: Bahr SFR na,41 E. Garnet Court BLD2005-00960 I Kell, I The geotechnical assessment level report prepared for the proposed Allen Bahr Single Family Residence (SFR)to be constructed at 41 East Garnet Court,Union,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, L— ;5. 1 n A. ja i File: H: \WP\GEO\Assessments\Bahr.dov I WORK ORDER - PUBLIC WORKS DEPT. 51 PERMIT M �"- cQ 14 ark Order Requested by; umbers Aulhodzed by: Type of Work Oate: CHARGE TO: NAME L� AGENCY/COMPANY BILLING ADDRESS �d �� PHONE Pub.WorksPerson M e; IO1 TNtte e:(from-to da�tteS _ e_ TO PI S Zo S Edlktd fkft Oft. mom 18TIMAM TOTAL ft ZZ NI lit! 000TWATE 0 am INS"* E� TOTAL i s�la �M ccavrPsaEKrvsEoe . iFl Aarw coa 3 ewu:: tea eY DATE sty Left Now TOTAL i EQUIPMENT USED: gal TOTAL MATEPJAI USED: 3► BILLED DATE TOTAL ALL PAID_DATE REC.N t,7r� CONSOLIDATED ENGINEERING - CIVIL - STRUCTURAL - SOILS - P NNING S. BOUGyy April 21, 2005 0 Al Bahr ONAU 90 East Kathryn Ct. Shelton, WA 98584 EXPIRES z�~�� SUBJ: GEO-TECHNICAL RECONNAISSANCE FOR A RESIDENCE OFF MCREAVY ROAD, MASON COUNTY, WA Dear Mr. Bahr: The undersigned Geo-technical Engineer, along with Lucas Anderson, Geo-technician, visited the subject site on April 20th in your presence for a preliminary soil survey and site reconnaissance. The site was investigated to determine the stability requirements for the siting of a proposed home. We found a slightly sloping lot in the front of the lot with a bank sloping down Northerly at 10 to 15 degrees as shot in the field. This is typical across the side of the lot. Generally, the land stability of the property is good due to the granular soil and gravel stratas. Our test hole and soil log revealed that the underlying soil is a glacial till, primarily of silty-sand with gravel inclusions. This is good foundation soil. A review of the Coastal Zone Atlas for a background in geology and slope stability revealed no recent landlides in the near vicinity of the lot. The lot is located near a zone listed as stable. The stability of the slope, the top of which is 65 feet Northerly of the access road and property line, is good. Photographs were taken of the site for our file and record. P.O. Box 2321 • Bremerton, WA 98310 • (360) 479-5598 Al Bahr April 21, 2005 Page 2 Due to the slope of the lot, this parcel required a Geo-technical Survey: (1) The area to the rear of the home is clear-cut and showed no distress from any slope instability. (2) The height of the slope across the lot to the North is about 15 feet. (3) The Site Plan contains the location of the home and the soils sample. (4) The soil sample type is a silty-sandy glacial till with gravel inclusions covered with a shallow strata of loam near the surface. (5) Groundwater was not observed on the site. (6) Silty-sandy soil was found in the exploration. (7) The lot is fairly open. A foundation planting of low shrubs is recommended at the completion of any additional construction. Drainage will be natural but impeeded by a seeded lawn. CONTENTS OF THIS GEO-TECHNICAL REPORT: 1. The basic soil, here, is a silty-sandy glacial till with gravel inclusions. 2. See the enclosed print of the Site Plan. 3. The exploratory hole location is shown on the Site Plan. 4. A temporary erosion control plan consisting of silt fences may be installed during the construction of the residence. 5. There are no known unstable areas of slope stability shown, nearby, in THE COASTAL ZONE ATLAS OF WA. Roof drains from the house should be carried in a closed conduit to discharge into an infiltration pit away from the foundations. No ground water was found. In my professional opinion, the proposed siting, described, herein, should provide a stable site for the home, the foundation of which is properly constructed. Yours truly, Rolla B.'Bough , P. E. GEO-TECHNICAL ENGINEER ENCL: Site Plan for Geo-technical Survey .B A3 A e ecS 5/TT PL Ail CONSOLIDATED ENGINEERING SHEET NO. n OF 1 ) P.O. Box 2321 �QQ 4 — BREMERTON, WASHINGTON 98310 CALCULATED Ci DATE (360) 479-5598 CHECKED BY DATE SCALE _ I I ; ; : k , , .......i. .............,... ...: . . ! I _.. ... : , , ....._a.. .._ ..... .._. *-- ...._.. } I .... ; i V E i i I i 1. _. ....... k ............. I ! I __.� ....._. _._._,.-------_fi..-.....t.._..._. ._...__.._..._...................................__..... .... ... F........... .._._..__........_�_..... jt ; } . . i ..._......;..._.................._. ...._..... ... 3.........._.�,.............}...... ._. C i .L._ \ .... Ll tt j t I. : I i ; 3 i t k ..._._...i.__._.-.:...___._.S._......-.:..._._......—_..}.._...._.�....._...7.--'— •_ _._ _.. -._ __.. _......f-.__....i.._.___— -- .— _.._ ..-.._i..._... : I : : i + i ( I I i � i _..... _.... . k ! 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