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HomeMy WebLinkAboutCOM2009-00040 GeoTech Report - COM Engineering / Geo-Tech Reports - 5/14/2009 MAY 14 2009 Mason County Department of Community Development M CC D - PLANNINC Submittal Checklist For a Geotechnical Report _ .rat Instructions: This checklist must be submitted with a Geotechnical Report and complet * lVd`ain, �td by the licensed professional(s)who prepared the Geotechnical Report forr Cnt to the Mason County Resource Ordinance. If an item found to be not Ap . po xplain the basis for the conclusion. Applicant/Owner: HARMONY HILL(Annex and Hillside Cab n) Parcel# 322334400040 Site Address: 7362 EAST SR-106, UNION, WASHINGTON 98592 (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) Page 2(Addendum 03-04-09) (b) A discussion of specific soil types Located on page(s) Page 4(Original Report 05-01-05) (c) A discussion of ground water conditions Located on page(s) Page 8(ORIGINAL Report 05-01-05) (d) A discussion of the upslope geomorphology Located on page(s) Page 1 (Addendum 03-04-09) (e) A discussion of the location of upland waterbodies and wetlands Located on page(s) Page 2(Addendum 03-04-09) (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the referenced maps and records Located on page(s) Page 3(Addendum 03-04-09) (2) A site plan, which identifies the important development and geologic features. Located on Map(s) Figure 2(Updated Site plan Figure 2) (3) Locations and logs of exploratory holes or probes. Located on Map(s) Figure 2(Updated site plan Figure 2) (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides, and toe) on a geologic map of the site. Located on Map(s) Figure 2(Update letter 05-11-09) (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details of proposed grade changes. Located on Map(s) Figure 4(Addendum 03-04-09) (6) A description and results of slope stability analyses performed for both static and seismic loading conditions. Analysis should examine worst-case failures. The analysis should include the Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5; the minimum seismic safety factor is 1.1 and the quasi-static analysis coeffients should be a value of 0.15. Located on page(s) Page 3-5(Addendum 03-04-09) (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) Page 10(Original Report 05-01-05) (b) Appropriate restrictions on placement of septic drain fields Located on page(s) NOT PROPOSED, Page 6 (Addendum 03-04-09) li (c) Appropriate restrictions on placement of compacted fills and footings Located on page(s) Page 7(Original Report 05-01-05) Pagel of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. i (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. a Located on page(s) Figure 2(Update 05-11-09 and figure 2 site plan) (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) Figure 2(Update 05-11-09 and figure 2 site plan) (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) Page 7(Original Report 05-01-05), Page 5-6(Addendum 03-04-09) (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. Located on page(s) Page 6(Addendum 03-04-09), (10) An analysis of both on-site and off-site impacts of the proposed development. Located on page(s) Page 6(Update 05-11-09) (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s) Covered in points 7 through 11 of this checklist (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) None Envisioned (13) 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. Located on Map(s) Figure 2(Update 05-11-09) I, Curtis D Cushman hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I g P 9 also certify that the Geotechnical Report, dated May 1, 2005, and entitled "Soils and Slope Analysis" and subsequent addendum dated March 04, 2009 and the subsequent update letter dated May 11, 2009 combined meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety. (Signature and Stamp) Wash;� � .3Z, nglneering geologist 0 2439 eased Ge0 CURTIS DEAN CUSHMAtd Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. f GEOTECHNICAE 1UTING ]LABORAT01ky RECEIVED MAY 14 AUS HARMONY HILL 7362 EAST STATE RouTE 106 M C C D - PLANNING UNioN,WA 98592 RE: GEOTECHNICAL REPORT UPDATE PROJECT: HARMONY HILL ANNEX AND HILL SIDE CABIN ADDITION 7362 EAST SR-106 UNION,WASHINGTON 98592 REPORT DATE: 5/11/2009 PARCEL: 322334400040 Gentleman: As per our conversation with Mr. Michael Whalen,we are providing an update letter for the above referenced project. It is our understanding that an annex building will be added to the existing guest house and two hillside cabins are proposed uphill from the existing multipurpose building. This letter addresses the pertinent geological hazard concerns raised by Mason County for the proposed development. We are providing three copies for your review and distribution. A careful revision of the original geotech report dated June 1, 2005 and a subsequent update dated March 4, 2009 was conducted to address any pertinent geologic hazard concerns for the proposed greenhouse. This letter and the attached update are to indicate that the original report and letters likewise apply to the newly proposed structures. It is our opinion that above mentioned original report, subsequent addendum letter and this update letter along with the standard checklist addresses the pertinent concerns concerning development in geological hazardous area inside Mason County. An updated site plan that includes proposed developments and associated setbacks available from active landslide hazard areas has been included along with this letter. An updated checklist is included with this letter for the specifics of the proposed development. The standard available setback for the proposed development has been updated on the site plan and is measured at approximately 112 feet for the proposed annex and over 250 feet for the proposed hillside cabins. Other pertinent geotechnical recommendations will be same as per the original geotechnical report dated June 1, 2005 and the subsequent update dated march 4,2009 for the proposed greenhouse addition within the parcel. It is our opinion that the proposed construction will not have any impacts on the adjacent slopes. Any other potential impacts are not envisioned as the proposed building locations have sufficient setbacks with respect to the adjacent slope and the septic drain fields. If you hav ' s regarding the same,please contact us at the following address. 0 ash. Sincerely, <. ^ginee►1%Geologist Curtis D Cushman, LEG 2439 �5` Senior Engineering Geologist �Sed Ge0\0 •l 10011 Blomberg Street SW,Olympia,WA 98512 1 Phone#: (360)754-4612 Fax#: (360)754-4848 L� SITE PLAN PROVIDED BY THE CLIENT. FILTER FABRIC M ATE RAL I VIDE ROLLS j FABRIC OVVIRE WIRE RING TOARACH Geotechnical FABRIC TO WIRE 2'1(7'X14 GAUGE WIRE FABRIC OR EQUIVALENT rT Testing s� SURFACE Laboratory r 8 MAX 2'X4'WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER BETTER OR EQUAL ALTERNATE: MATERIAL IN 7'X17 TRENCH STEEL FENCE POSTS V V FILTER FABRIC C 2-X2'X14 GAUGE MARE FABRIC OR EOUNALENT 7 GROUND SURFACE B4T PROVIDE 3'4'.1 1?WASHED GRAVEL BACKFILL IN TRENCH 1S AND ON BOTH SIDES OF FILTER FENCE FABRIC ON THE SURFACE 8'MI \ L I 1 7X4'\A000 POSTS 1 ALT'STEEL FENCE POSTS Geotechnical Services r-----_J I FILTER FABRIC FENCE NOTES: QA/QC Services 1.FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF THERRIER TO AVOID USE OF JOINTS,WHEN JOINTS ARE NECESSARY.FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT Testing Services A SUPPORT POST WITH A MINIMUM 6-INC H OVERLAP AND SECURELY FASTENED AT BOTH ENDS TO THE POST. / \ Qa \ � ) 2.POSTS SHALL SPACED MAXIMUM OF8FEET APART AND DRIVEN o FOOTPATH , '\I p y��\ SECURELY INTOO THE GROUND (MINIMUM OF 301NCHE3). / // �' /// %i' ^\\\\ \\ 1 \'\ \• 1 3-A TRENCH SHALL BE EXCAVATED APPROXIMATELY8 INCHES WIDE AND 12 10011 Blomberg St.SW \ a1D 1 1 INCHES DEEP ALONG THE LINE OF POSTS ND UPSLOPE FROM THE BARRIER. Olympia,WA 98512 O/ 1 I 1.WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH Phone:(360)754-4612 \v I SUPPORT FENCE SHALL BE FASTENED SECURELY TOE UPSLOPE SIDE OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1 INCH / / \\ \\ I Srmo ``• (1 j LONG,TIE WIRES OR HOG RINGS.THE WARE SHALL EXTEND INTO THE Fax:(360)754-4848 1 1 TITENCH A MINIMUIA OF 41NCHE5 AND SHALL NOT EXTEND MORE THAN 38 08p0 \\\\ \\\\ II \\\ / 1 \Q ) 1 INCHES ABOVE THE ORIGINAL GROUND SURFACE. / �iG �7 1 5.THE STANDARD STRENGTH FILTER FABRIC SHALL BE STAPLED OR WIRED 1 TO THE FENCE AND 20INCHES OF FABRIC SHALL BE EXTENDED Date: 03/2/2009 / \ \ 1 1 I ' ` 1 INTO THE TRENCH.THE FABRIC SHALL NOT EXTEND MORE THAN 38 \ \ 1 nN� Designed by:MICHAEL WHALEN INCHES ABOVE THE ORIGINAL GROUND bURFACE.FILTER FABRIC SHALL U,p 1 1 NOT BE STAPLED TO THE EXISTING TREES. Drawn by: VC 8.WHEN EXTRASTRENGTH FILTER FABRIC AND CLOSER POST SPACING IS Checked by: CDC \\ \ \\ I \ \ ) \ USED,THE WARE MESH SUPPORT FENCE MAP BE ELIMINATED,IN SUCH 201 O' ACASE,THEFILTERFABRICISSTAPLEDORWWREDDIRECTLYTOTHE Dwg#:03-03-09-003 I I 1 \ \ \ POSTS WITH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING 08po \; Q�6 41' HOOD CANAL 80' COTT 1 1 1 7.FILTER FABRIC FENCES SHALL NOT BI REMOVED BEFORE E UPSLOPE AREA HAS BEEN PERMANENTLY STABILIZED. / / \ I 1 1 1 1 8.FILTER FABRIC FENCESSHALL DURING INSPECTED NGEDU INFALLAFTER ANEACH I 1 \\ \\ \\ \\\ '\ \ 1 RAINFALL AND AT S SHAL AILY EIMMEDIATELY. RAINFALL.ANY I I \\ \\\ \\ \ I 1 ' II \ \ \\ REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. �00 \ ENTRYDRIV AY �\ 1 GENERAL EROSION CONTROL NOTES: I \\\ 120' 1 7. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE 1 BEGtNSHALL INSPECT ONSTRUCTION. EINSTALLAHE TENOINEERAND THE COUNTY SHALL INSPECT AND APPROVE THE INSTALLATION OF % 14V ; Qapo 1 11 EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. 160' I 1\ 1 \\ 11 Y.ONOTIIIS PL N THE CONTRACTORS NOT FTHE OR THE 180p/� INSTALLATION AND MAINTAINANCE OF ALL EROSION CONTROL MEASURES. ' I 1 1\ MULTI \'I GA'D- ��aH I\ `I A NO SILTATION OFEXI STING OR PROPOSED DRAINAGEFACILITIES PROJECT NAME: 1 PURPOSE 1 G 1\ I 1 SHALL BE ALLOWED.CARE SHALL BETAKEN TO PREVENTMKWATION HARMONY HILL ANNEX& \\ 200' I BUILDING I I 11 OF SILTS TO OFF SITE PROPERTIES. 22�' \\ \\ 11 OPlID 1 \'I 3.THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION HILLSIDE CABIN ADDITION \ , / MpIH GU �1 I 1 ` CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS / 240 \\ \\ \ \\ I 11 1111 1 TO THE EROSION CONTROL MEASURES.THE CONTRACTOR SHALL PROVIDE 7362 EAST SR-106 ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY A I,FBRLE I i I 11 BY THEC OUNTYINSPECTORANDIORTHEPROJECTENGINEER.FAILURE UNION,WASHINGTON 1 TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL \ \ \ \ \ 1 \ 1 I I REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED (� �T ',T w /�,� IGUEST � I I aGAINSTTHE CONTRACTOR AND/OR PROJECT OWNER. PARCEL 322334400040 4,DURING THE WET SEASON(NOVEMBER TO AMRCM ALL DISTURBED SOILS SHALL BE STABILRED WITHIN 48 HOURS AFTER STOP OF WORK EROSION CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, COVERING THE EFFECTED AREA INCLUDING SPOIL PILESWITHI 04117109 R/evAisron$(T: \\ \\ \ \ I ' 50' / I I I PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH, U}I I�I U' \ \\ \ \ 1 PROPOSED liILL81DE CABINS \y I / I I 04 1 09 SETBACK 250 FOOT FROM ACTIVE LANDSLIDE I 9 \� PPLLAC�WEAP�R PAS SF THE DISTURBED AREAS SHALL TAKE \ \ \ I HAZARD AREA I 1 1\ / \CUSS PROP SE') I // \ I I I 5.ALL SEEDED E SODDED AREAS CO SHALL BE CHECKED REGULARLY 05108109 TO MAKE SURE VEGETATIVE COVERAGE IS COMLETF AREAS SHALL BE ANNEX I I �I REPAIRED,RESEEDED,AND FERTILIZED AS REQUIRED. TRACKING OF SAL OFFSITE WALL NOT BE ALLOWED.IF ANY SOIL IS TRACKED ONTO A COUNTY STREET,R SHALL BE REMOVED BY THE ENO 0 OF 1 I OF THAT WORKING DAY.ANY FURTHER TRACKING OF MUD WALL THEN tit/r�F�r�N�S(/ ��'/qp��,',�1 c• I. I I BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES TIRES \ I1 1 11 D V FGeTA� "1/ w ( I EFORE DRIVING ON A COUNTY STREET. 7.NO MORE PERCENT SHALL TTHAN 00 LF OF OPENED ONETIMECDOWNSLOPE OF MORE THAN STREAM S.EXCAVATED MATERIAL SHALL BE PLACED ONE UPHILL SIDE OF TRENCHES. B.TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN MANNER THAT WLL NOT ADVERSELY AFFECT FLOWING STREAMS.DRAINAGE SYSTEMS OR OFFSITE PROPERTIES. 10.ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING SCALE:1 Inch=125 feet CONSTRUCTION SHALL BE PROTECTED SO THAT SEDIMENT-LADEN VOTER SCALE: 1" = 125 FEET WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. 11.ALL OFF41TE CATCH BASINS IMMEDIATELY ADJACENT TOE SITE SHALL BE PROTECTED FROM SILTATION, FIGURE 2 O 50 100 200 12,ALL DISTURBED AREAS SHALL BE SEEDED OR SODDED UPON COMPLETION OF WORK THE CONTRACTOR SHALL BE RESPONSIBLE TO ENSURE THAT COMPLETE COVERAGE OF THE DISTURBED AREAS IS PROVIDED 3 THAT GROWTH OF THE VEGETATION IS ESTABLISHED. 17.CATCH BASINS SMALL TRAP EETA OR FILTER FABRIC MUST BE SITE PLAN PLACED UNDER GRATE UNTILL V VEGGETATION IS ESTABLISHED.