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Home My WebLink AboutGEO2017-00054 Assessment - GEO Geological Review - 9/6/2017 r i ��201 ;7 PLANNING EROY SURVEYORS & ENGINEERS, lN�. Surveying• Engineering•Geotagy•Septic Design•GPS•GIS Mapping w Christine Milliron August 712C7_ ��a E�D 23027 NE 159th ST R C C V Woodinville, WA 98333 425-218-8640 SEP 0 6 2017 Landslide Hazard Geological Assessm'%15 W. Alder Street Parcel No. 12220-54-00101 Site Address—81 East Channel DR LS&E Job No. 11457 Assessment Performed:July 6, 2017 Introduction A landslide hazard geological assessment is necessary for the proposed construction of a new single-family home on the above-referenced site given the presence of slopes in excess of 15 percent(approximately 20 percent locally) as per the Mason County Critical Area Ordinance Section 8.52.140. Through this assessment,we conducted a site reconnaissance and inspected the area slopes for the presence of landslide hazard indicators. We also studied subsurface r conditions via several in-situ test excavations and through available published records. Finally, we reviewed aerial photography,topographical maps, and geological maps to help gain an understanding of the regional morphology and geology in order to establish an opinion on relative slope stability. This report is for the exclusive use of Christine Milliron, and the consultants and contractors for the intended purpose described. Site observations described represent the standard of practices for the industry. Sources of information cited are uniformly accepted resources when utilized in conjunction with field reconnaissance as confirmation. Opinions are based on these standardized practices to adequately characterize the local surficial geology and general conditions. Information Sources Soil identification and mapping for this assessment is supported by information from the Natural Resource Conservation Service (the Survey). Geologic information for this assessment is supported by information from the Washington State Department of Natural Resources (DNR) Geologic Map of the Belfair 7.5 Minute Quadrangle, Washington (Belfair). Our understanding of site geology is supported by the review of geologic mapping, published topographic and relief map layers from the Pierce County Geographical Information System (GIS), and site observations. Our opinions are based on our interpretation of the cumulative information and the contemporary conditions of the geologic setting. Published Information Accuracy It should be noted that the Survey,the USGS and/or DNR geologic maps, and the Mason County GIS define general areas of soil deposits,geology, and landforms. Given the large areas to identify and limited sample points,the authors of the above sources commonly inferred boundaries, contacts, and other representations in some areas. On site reconnaissance is necessary to further detail, adjust, or confirm information from the maps as they relate to each LeRoy Surveyors&Engineers,Inc.•P.O.Box 740,Puyallup,Washington 98371 253.848.6608 •fax 253.840.4140 •www.iseinc.com A Christine Milliron August 7,2017 Page 2 of 9 site. The maps are not(from our experience)accurate on a lot by lot basis in all cases. In this case, the Survey and the Geologic Maps are generally in concurrence with observed field conditions. Site Description General This approximately 0.5 acre lot is located within the plat of Lakeland Village No. 5 (Lot#101). It is one of the few remaining undeveloped lots within the subdivision. It is situated on an approximately 20 percent slope descending from northwest to southeast for an elevation change of approximately 52 feet in 254 feet. The top of the slope originates at East Channel Drive and the toe of the slope terminates along a lower property line, and specifically terminating at the neighboring building site's development pad. A short cut scarp exists along the lower boundary where the underlying glacial till can be observed. The site is heavily vegetated with second growth forest species and typical native understory. Figure 1 illustrates the lot terrain and position in the subdivision. Figure 1—Lot#101 Terrain, Dimensions, and Test Pit Locations .�_ 17 _v5rr `E_ 7 • _ 1.77 V .•r'r,,E, "4E-' -1,..) iJ�.J a a' LT i L SL) o u #10 2 LOT A 5L-Ij' Mp S.W3225' E 134,00' Soil As discussed in the 'Published Information Accuracy' section above; on-site reconnaissance is necessary to verify soil conditions on specific properties. In this case, we found the geologic map and the soil Survey in agreement with each other and with conditions observed on the site. Specifically,the Survey identifies the Alderwood gravelly sandy loam as the predominant soil type for the site and nearby region. Through test pit excavation we were able to make observations and measurements of the soil conditions on representative locations throughout LeRoy Surveyors&Engineers,Inc.•P.O.Box 740,Puyallup,Washington 98371 253.848.6608 •fax 253.840.4140 •www.iseire corn i Christine Milliron August 7,2017 Page 3 of 9 the lot. Our observations confirmed the Survey identification (see attached soil descriptions). Figure 2 illustrates the Survey's Soil identification in the area. Figure 2—NRCS Soil Map&Soil Unit Descriptions h _® :gym 1 Site �Sdu IW.D'J(itrlonAbtd�lL'.&S^dY. c a a sm ,a � ae.ras,s.�ma,r.=+A;as s�m:mim..iaw� LeRoy Surveyors&Engineers,Inc.• P.O.Box 740,Puyallup,Washington 98371 253,848.6608 •fax 253.840,4140 • www.tseinc.com Christine Milliron August 7,2017 Page 4 of 9 Table 1 -Soil Map Unit Descriptions Mason County,Washington(WA645) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI Ab Aldenvood gravelly sandy ' 8 1.8% loam.8 to 15 percent slopes Ac Alderwood gravelly sandy 303 30.2% loam, 15 to 30 percent slopes Ea Edmonds fine sandy loam.0 to b 1 8% 2 percent slopes Ed Evereft gravelly loamy sand.0 76 7 6% to 5 percent slopes Jc Juno loamy sand.0 to 3 percent slopes i Mg Mukitteo peat,0 to 2 percent 25 2 5% slopes So Sinclair shotty toam,5 to 15 498 49 6% percent slopes Tn Trdal marsh,0 to 2 percent 25 2.5% slopes W Water 2-9 2 9% Totals for Area of Interest 100.4 100.0% The Alderwood gravelly sandy loam is moderately well drained. It formed in glacial till on broad plains in the Puget Sound lowland. Predominant native vegetation is made up of hardwoods and conifers. The typical elevation of this soil series ranges from 200 to 800 feet. In a typical soil profile, a mat of undecomposed needles and wood fragments rests upon a 1 inch thick very dark grayish brown gravelly sandy loam surface layer. The subsoil and the upper part of the substratum,to a depth of 38 to 45 inches, are dark yellowish brown, brown, and dark grayish brown gravelly sandy loam. The lower part of the substratum, to a depth of more than 60 inches, is weakly cemented compact glacial till. A seasonal water table is perched above the very slowly permeable, weakly cemented and compact part of the substratum during periods of heavy rainfall. However, the perched water table is of short duration because the water flows laterally above this layer to seeps at the bottom of slopes. Very few roots penetrate this dense substratum. The available water capacity is low. Surface runoff is medium, and the erosion hazard is moderate. Geology As illustrated on the Belfair Geologic Map, the property is situated on a moderately inclined side slope of an elongated glacial till drumlin. Drumlins can be described as elongated mounds of compact glacial drift deposits (lodgement till in this case), whose long axes are aligned in the direction of ice advance. The majority of the drumlin terrain we see throughout the Puget Sound region was emplaced and formed during the most recent Vashon stade glacial period. Figure 3, below, illustrates the geology of the site and surrounding environment. LeRoy Surveyors&Engineers,Inc.• P.O.Box 740,Puyallup,Washington 98371 253.848.6608 •fax 253.840.4140 •www.iseinc.com l Christine Milliron August 7,2017 Page 5 of 9 Figure 3—Geologic Map of the Belfair 7.5 Minute Quadrangle(Excerpt) ('� ♦ Q Site QOb �• ;� �r J �j Qaf P Qa 0 r , /� Qm Q Is � �� !` - Qob /Qa� Qa,. - -- `- - � Michael Polenz, Katelin Alldritt, Nicholas J. Hehemann, Isabelle Y. Sarikhan, Robert L. Logan (July 2009) Description of Map Units Qgt Vashou till—Unsorted.unstratified(bill locally banded)mix of clay.silt. sand.and aral-el:typically supported by a sandy matrix:mostly gray but locally-ralmillia to tan_li_llt brown.or orange:hpicalty unweathered: lodgment till compact.with well-developed facies resembling concrete. but near the surface coumlonly hackly and(or)looser and covered by 1 to 6 it of loose ablation till:deposited directly by glacial ice and conwlonly includes ciasts or clumps plucked from lulderlying units.Clasts are collmionly striated and faceted.with anaular of rounded edges.Boulders are generally sparse within the till but large(erratic)boulders of plutonic of metamorphic Pock are con nlon oil till Surfaces. Some exposures include interbands and lenses of sand and travel.locally with shears and Joints. Till forms a locally patchy and seemingly randomly distributed corer up to a several tens of feet thick.with a thickness of S to 20 It most common.It typically dominates,but is also locally discontinuous on,fluted surfaces. with illdrl'idual drumlins measurina 0.1 to 0.3 mi bride by 0.8 to 1.3 rni Ions and the long axis aligned with the direction of ice flow.Till typically is in sharp.unconfornrable contact with underlying units.most commonly- advance ouavasli(unit Qga and submit), Unit Qgt lies stratigraphically- below unit Qgo.It may include unrecognized exposures of older till.A reap boundary mi match beriveen unit Qgt on this map and tout Qsos nn the'auglui quadrangle to the south slogan and Walsh.200"}may have resulted from a reap-production error ill the northwest corner of the Vaughn map(Josh Logan.Wash Dian.of Geology and Earth Resources, oral conunml..20091. LeRoy Surveyors&Engineers,Inc.• P.O Box 740,Puyallup.Washington 98371 253.848.6608 •fax 253.840.4140 • www.iseinc.com r R Christine Milliron August 7,2017 Page 6 of 9 Landslide Hazard Assessment On July 6, 2017, a Licensed Geologist from LS&E performed a site reconnaissance for the presence of indicators associated with landforms susceptible, or undergoing mass movement due to a combination of geologic, seismic, topographic, hydrologic, or manmade factors. Per Mason County Title 8—Environmental Policy, Chapter 8.52.140 Landslide hazard areas can be classified by the presence of any of the following indicators: (A) The following shall be classified as landslide hazard areas: (i)Areas with any indications of earth movement such as debris slides, earthflows, slumps and rock falls(see Figure F 100). (ii) Areas with artificial oversteepened or unengineered slopes, i.e., cuts or fills. (iii)Areas with slopes containing soft or potentially liquefiable soils. (iv) Areas oversteepened or otherwise unstable as a result of stream incision, stream bank erosion, and undercutting by wave action. (v)Slopes greater than fifteen percent (8.5 degrees) and having the following: A. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock(e.g., sand overlying clay); and B. Springs or groundwater seepage. (vi) Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas composed of consolidated rock.A slope is delineated by establishing its toe and top and measured by averaging the inclination over at least ten feet of vertical relief. Findings and Conclusions During our site reconnaissance, we did not observe any of the landslide hazard area classification indicators in the above list. Further review of the site morphology, terrain, and stability mapping has been possible through our review available published literature. These sources include: 1._The Geologic Map of the Belfair 7.5 Minute Quadrangle, 2. The topographic mapping performed by 4Sight Surveying and Consulting (12-29-2015), and 3. The Washington Department of Ecology Coastal Zone Atlas, Volume 9—Slope Stability Maps (See Figure 4). The geologic map shows no landslide terrain on or within the influence of the site as would be noted by Quaternary Landslide Deposits (Qls). The topography shows planar slopes throughout the area as would be produced by ice advance, and does not show altered slope faces as would be produced by slope failure events. The D.O.E. Coastal Zone Atlas classifies the slopes as 'Stable' (See Figure 4 below). LeRoy Surveyors&Engineers,Inc.•P.O.Box 740,Puyallup.Washington 98371 253.848.6608 •fax 253.840,4140 •www.lseinc.com 4 Christine Milliron August 7,2017 Page 7 of 9 Figure 4—D.O.E. Slope Stability Map Legend fi NN - Yy: Y �-' S+e1N9 NTNs 9HM ally rvSP IMs UYen i '�1�• } # �� PeOB.BiLfiQ(N lad'IXBBS O+Wi1 _w } Q+IXCiQMill CM[B!+Cd�'S:D'CatgetBnl .fir -I Y .ef" MdOfk StaPN {IyW pl4nq glYkly M#bwkfN(f J(q,Mek1 pY p C T % _ as uvsea la unaa peat ee neaas:n mzn rtRougR vae+n+�«�.nare no s�acec ,. ,. In.rme•'f v+WpFs rn 9eRr�ry sKeo9 men + percaM cxcepr ww?cmaica,s sucn s }' woakm mrerei mRa adlndn:growO+retr N,-d M woes mCNk18 skpe6 m ar» - erA Pawl N.¢Yw:5qs Gvr rveC-ock wRR keYC Mkl+Ovt+fe.SWfS Based on our site reconnaissance along with a cumulative review of the above-mentioned published sources, it is our opinion that the natural slope throughout the site appears globally stable and not at risk for landslide or mass movement. In our opinion, the construction of a single-family home on the site along with the necessary site development and improvements will not create any slope stability issues, particularly if site development adheres to the current permitting and inspection processes. Recommendations Anytime construction will occur on moderate slopes, it is necessary to require the appropriate site development controls to prevent temporary and permanent erosion, and to provide permanent storm water control. We understand that Mason County provides the applicant's site development contractor with the standards required and requires written acceptance of the stanards. Stormwater—Through our substantial experience conducting infiltration testing in many soil types, and many times in the Alderwood series,we can estimate a typical infiltration rate and recommend a more conservative design rate. In our experience,these Alderwood type gravelly fine sands (with minor silt) regularly allow infiltration rates well over 30 inches per hour and in several cases, more. We recommend a rate of no more than 12 inches per hour for design. Closure The conclusions and recommendations presented in this assessment are based, in part, on our observations, interpretations, and assumptions regarding shallow subsurface conditions; therefore, if variations in the site conditions are observed at a later time, we may need to modify this letter to reflect those changes. We appreciate the opportunity to be of service on this project. If you have any questions regarding this letter or any aspects of the project, please feel free to contact our office. LeRoy Surveyors&Engineers,Inc.• P.O.Box 740,Puyallup,Washington 98371 253.848.6608 • fax 253.840.4140 a www.Iseinc.com I _ r Christine Milliron August 7,2017 Page 8 of 9 Respectfully submitted, LeRoy Surveyors & Engineers, Inc. g o7 160 Wif.UAM REVELING Bill Creveling, L.G. Licensed Geologist LeRoy Surveyors&Engineers.Inc.•P.O.Box 740,Puyallup,Washington 98371 253.848.6608 •fax 253.840.4140 •www.Iseinc.com Christine Milliron August 7,2017 Page 9 of 9 Soil Logs July 6, 2017 LeRoy Surveyors&Engineers,Inc.• P.O.Box 740,Puyallup,Washington 98371 253.848.6608 •fax 253.840.4140 •www.lseinc.com ;ItEROY SURVEYORS & ENGINEERS, INC. - Surveying•Engineering•Geology•Septic Design•GPS•GIS Mapping —�— BORE HOLE NUMBER: SPA Client: Christine Milliron Project Number: 11457 Project Name: Milliron Geotechnical Date Started: 7/6/2017 Project Location: 81 East Channel Drive Date completed. 7/6/2017 Ground Elevation: 458' _ Size: 2 ft X 6 ft Excavation Contractor: OWNER Ground Water Levels: At Time of Excavation NONE Excavation Method: Rubber Track Mini-Excavator NONE At End of Excavation Logged By: BC Checked By: BC Static Water Depth NONE NOTES: O a J W. U W W a o=. 0 a 2 MATERIAL DESCRIPTION LU D a z o - —— ——-- ----- ------- ---------, Sand and Silt: brn,with gravel I I I SM i 1 I I SP Weathered TILL:gray, compact,gravelly i SP Till:gray,compact, dense,mottled i I I I I I i I � � -10 The depths on the test pit logs are based on an average of measurements across the test pit and should be consideamturate to+/-0.5 ft. Bottom of Expoloration 4.1 ft Ground Water/Seepage None Observed Side Wail Caving None Observed EROY SURVEYORS_& ENGINEERS, INC. Surveying•Engineering•Geology•Septic Design•GPS•GIS Mapping BORE HOLE NUMBER: SP-2 Client: Christine Milliron Project Number: 11457 Project Name: Milliron Geotechnical Date Started: 7/6/2017 Project Location: 81 East Channel Drive Date completed: 7/6/2017 Ground Elevation: 472' Size: 2 ft X 6 ft Excavation Contractor: OWNER Ground Water Levels: At Time of Excavation NONE Excavation Method: Rubber Track Mini-Excavator NONE At End of Excavation Logged By: BC Checked By: BC Static Water Depth NONE NOTES: _ O a J U W m a a h CL MATERIAL DESCRIPTION WG D Q Z N o - T ---------'--- Sand and Silt:bm,with gravel SM SIP Weathered TILL:gray, compact,gravelly Sp Till:gray,compact,dense,mottled I I 1 I I I —J The depths on the test pit logs are based on an average of measurements across the test pit and should be consideeaturate to+/-0.5 ft. Bottom of Expoloration 3.2 ft Ground Water/Seepage None Observed Side Wall Caving None Observed EROY SURVEYORS & ENGINEERS, INC. Surveying•Engineering•Geology•Septic Design•GPS•GIS Mapping BORE HOLE NUMBER: SP-3 Client: Christine Milliron Project Number: 11457 Project Name: Milliron Geotechnical Date Started: 7/6/2017 Project Location: 81 East Channel Drive Date completed: 7/6/2017 Ground Elevation: 488' Size: 2 ft X 6 ft Ground Water Levels: Excavation Contractor: OWNER NONE At Time of Excavation Excavation Method: Rubber Track Mini-Excavator NONE At End of Excavation _ Logged By: BC Checked By: BC Static Water Depth NONE - NOTES: O a O J Lu tJ W m a v a g MATERIAL DESCRIPTION w i o O y o �— — -----— ------- —— Sand and Silt:brn,with gravel i SM V i Sp i Weathered TILL:gray,compact,gravelly Sp Till:gray,compact,dense,mottled -10 I I � I I i I i The depths on the test pit logs are based on an average of measurements across the test pit and should be consideemturate to+/-0.5 It Bottom of Expoloration 3.5 ft Ground Water/Seepage None Observed Side Wall Caving None Observed GEO ell - Mason County Review Checklist For a Geological Assessment Instructions: This checklist is intended to assist Staff in the review of a Geological Assessment. The Assessment is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not applicable, the report should explain the basis for the conclusion. The Assessment is also reviewed for clarity and consistency. If the drawings, discussion, or recommendations are not understandable, they should be clarified. If they do not appear internally consistent or consistent with the application or observations on site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should refer the case to the Planning Manager or Director. Applicant's Name: Permit#: 6 L LM ") I:7' 00 (0 o Parcel#'s: I a C7 54— 06 10 Date(s)of the Document(s) reviewed: AU , Z�) 1. A discussion of geologic conditions in the general vicinity of the proposed development, with geologic unit designation based on referenced maps. OK? Comment: 2. (a) A discussion of the ground water conditions at the site, OK? Comment: (b) A discussion of the estimated depth to water, OK? �_Comment: (c) A discussion of the quantity of surface seepage, OK? Comment: (d) A discussion of the upslope geomorphology, OK? Comment: (e) A discussion of location of upland waterbodies and wetlands. OK? _Comment: 3. The approximate depth to hard or dense competent soil, e.g. glacial till or outwash sand. OK? _Comment: 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.). OK?_X Comment: 5. A discussion of the history of landslide activity in the vicinity, as available in the referenced maps and records. OK? _Comment: 6. An opinion on whether the proposed development is within the landslide hazard area or its associated buffer or setback and the /potential for landslide activity at the site in light of the proposed development. OK? % Comment: 7. A recommendation by the preparer whether a Geotechnical Report should be required to further evaluate site conditions and the proposed development of the subject property. OK? _Comment: S B. If the presence of a hazard is determined within 300 feet of the proposed development, then the following are delineated on a geologic map/site map: Page 1 of 2 Form Effective June 2008 (a) the area of the proposed devefopmen OK? �C Comment: N (b) the boundaries of the landslide hazard area(top, both sides, and toe), 1 OK? X Comment: (c) the assosi)<ted buffers(top, both sides, and toe) OK? Comment: (d) building or other setbacks (top, both sides, and toe). OK? Comment: 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. OK? X Comment: Are the Documents Ted and stamped? By whom? License#: �� J License type: FIRST REVIEW Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? I Time spent in revievv: Reviewed by ��L t--� on SECOND REVIEW/UPDATE ❑ Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by on . Time spent in second review: THIRD REVIEW/UPDATE ❑ Approved ❑ Need more info. If not approved, what is the next action/recommendation for further action? Reviewed by , on .Time spent in third review: Disclaimer., Mason County does not certify the quality of the work done in this Geological Assessment Page 2 of 2 Form Effective June 2008 Mason County Department of Community Development Submittal Checklist For a Geological Assessment Instructions: This checklist must be submitted with a Geological Assessment and completed,signed,and stamped by the licensed professional(s)who prepared the Geological Assessment for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable,the report should explain the basis for the conclusion. tr Applicant/Owner Urlstioe. Ij( 11Parcel# f 2 Z 2 D oo 1 to Site Address G n Y1 ! {` ))(A (1) A discussion of geologic conditions in the general vicinity of the proposed development,with geologic unit designation based on referenced maps. Located on page(s) "1 f 11 (2) (a)A discussion of the ground water conditions at the site, L�li Located on page(s) _f %ck Spi 1 1�S 44A �-Y�f'1 I� J (b) A discussion of the estimated depth to water Located on page(s)_7if ?2 (c) A discussion of the qu ntity of surfaces a e ,_ s` � Located on pages) � —' e)onle �fYe` t t1 (d) A discussion of the upsloW geomorphology Located on page(s) 4 �i (e) A discussion of location of upland waterb dies and wetlands. Located on pages) � � "- ,vLj-c ew),hrt ups , rp lOt1 aS e b ��b d�`1��'s�V a -n o I�sj bt e 14 (3) The approximate depth to ha or d se compe e�it soil,e.9.placi I till or outw sh sand. Located on pages) — vV 4P�Cr1oh '�$"��"� (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 hed trees in icating doyrnslope movement,etc.). Located on paws) d (5) A discussion of the history of landslide activity in the vicinity,as available in the referenced maps and records. Located on page(s) (6) An opinion on whether the proposed development is within the landslide hazard area or its associated buffer or setback and the potential for landslide activity at the site in light of the proposed develop nt. Located on page(s' (7) A recommendation by the preparer whether a Geotechnical Report should be required to further evaluate site conditions and the proposed development of the subject property. Page 1 of 2 Form Effective June 2008 i Located onpage(s) otand �at» ��aCl» fi�v�cur, Pa�v r! doPs h�� re�o�r�1 (8) If the presence of a hazard is determined within 300 feet of the proposed development, �" ��o,4- then the following are delineated on a geologic map/site map: (a) the area of the proposed developm nt, Located on Map(s) (b) the boundaries of the landslide hazard rea(top,both sides,and toe), Located on Map(s) t,l (c) the associated buffers(top, both si A,and toe) Located on Map(s) ij (d) building or other setbacks(top,both,,fi�ides,and toe). Located on Map(s) (9) A site map drawn to scale showing the property boundaries,scale,north arrow,and the location and nature of exist' g and [oposed evellg�p ent on he site. Located on Map(s) ,t�11JgN 1, i �V-io�)JP-A (04A hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineerin a geologi r engineering geologist licensed in the State of Washington with special kno e e local conditions.I aalso certify th at the Geological Assessment, dated AI and'entitled t��-�n�Sl(�� GI OCA k 0 ri, f�S ►1 meets all the requirements of the ason County Resource Ordin ce, 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• � 1�� y 1604 WILUW D.ci&-t NG Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment. Page 2 of 2 Form Effective June 2008 rum .D RO VI\ t in C jC�C 'fit j�1�1 •'1 ( e). }Rn n P