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HomeMy WebLinkAboutGEO2011-00016 - GEO Geological Review - 8/25/2008 RECEIVED EO 2,�`I I • oOC� (41 ALLEN L. HART ENGINEERING GEOLOGIST 35 MASON CUUN it 1720 North Oakes, Tacoma, Washington 98406 (253) 752-8963 August 25, 2008 'f0 BE l� � �' ;i� 4 i Project No. 0808031 Drew Davies Land and Home Appraisal 4843 Auto Center Way, Suite B Bremerton, Washington 98312 Report of Soil Study and Geological Assessment Proposed Single-Family Residence Building Sites Allyn Block 28, Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn, Mason County,Washington This report presents the results of a soil and slope review and geologic assessment directed at evaluating potential geologic hazards at the referenced site. The scope of this study was developed during our site visit on August 12, 2008, at which time verbal authorization to proceed with the study was received. Site Location and Proposed Development The subject lots are located on the west side of East Blackwell Street, approximately 600 feet north of the intersection of Blackwell Street and East Wade Street in Allyn, Washington, as shown on the Vicinity Map, Figure 1 of this report. Specific lot locations are shown on Figures 2 and 3. The subject lots are approximately 132 feet deep with a 40 foot width. As presently conceived the building envelopes are set back from the front property line approximately 40 feet with the actual building envelope being approximately 45 feet deep and 29 feet wide. It is understood that as presently designed the residences will be typical wood-framed structures constructed over a garage, which depending on finished grades may be partly daylighted into the low angle site slopes. It is anticipated that general grading for site development will be minimal and no slopes will be steepened for development. Following construction all areas of bare soil will be re-vegetated and landscaped such that the potential for the post-construction development of erosion and/or landslide hazards is minimized or eliminated. GEOLOGIC AND GEOTECHNICAL CONSULTING Project No.0808031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.2 Methodology Soil and slope conditions of the subject property were visually examined and evaluated using available slope exposures and road cuts in the site vicinity. Additionally soil logs for water wells in the general site vicinity were reviewed. Approximate soil log locations are shown on Figure 4 with the logs presented on Figures 5 through 9. On site information combined with various soil exposures around the site provided a basis for a general understanding of the local soil and geologic conditions as discussed below. In addition to the observation of available soil exposures a reconnaissance of the area was completed and readily available geologic and soil maps reviewed. Resources used: 1. "Geology and Related Ground Water Occurrence, Southeastern Mason County, Washington", Water Supply Bulletin#29, Washington State Department of Water Resources, 1970. 2. "Washington State Coastal Zone Atlas, Mason County volume" 3. "Soil Survey of Mason County Washington", United States Department of Agriculture, Soil Conservation Service(SCS),1960 4. USDA,Natural Resources Conservation Service(NRCS), On Line Reports, "Washington State Soil Survey Reports" 5. "Relative Slope Stability of the Southern Hood Canal Area, Washington,"Map I-853-F, Washington State Department of Natural Resources, Division of Geology and Earth Resources, 1977. 6. "Belfair Quadrangle, Washington", U.S.G.S. 7.5 minute series topographic map. 7. Lidar images and aerial photographs 8. Available water well soil logs from the Washington State Department of Ecology web site. Distance and slope measurements referenced in this report were determined in the field by pacing and using small, handheld equipment, i.e., Brunton compass, Suunto inclinometer,tape measure, and optical and laser range frIders. All measurements should be considered accurate to the degree implied by the method used. Fieldwork and data acquisition for this assessment was undertaken between August 12, 2008 and August 25, 2008 with both dates being inclusive. ALLEN L.HART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Project No.0908031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.3 Geoloeic Setting The site is located in the south-central portion of Puget lowlands, an elongate, north-south trending structural depression and topographic trough. The Puget lowlands have been filled several times by glacial ice,resulting in many topographic features that are a result of both glacial and post-glacial erosion and deposition. Site soils, topography and geology result primarily from the advance and retreat of the Vashon Stade(most recent glacial advance)of the Frazier Continental Glaciation. In the general project area the typical soils appear to be a medium dense to dense sand and gravel(Recessional Outwash)mantle overlying a dense to very dense lodgement glacial till, which is underlain at depth by Advance Outwash deposits. The glacial till in the area is generally comprised of a mixture of sand, silt and gravel picked up by the ice sheet as it moved, then deposited at the base of the glacier and overridden and densified by some 1,500 to 3,000 or more feet of ice. The general appearance of the till is similar to a very dense, lean concrete. Both the Advance Outwash and the Recessional Outwash are comprised of gravels and sands with varying amounts of silt and clay. Surface Conditions Average slopes across the two lots were field measured and found to range from about 7 degrees to 9 degrees(approximately 12%to 15.8%)with short localized sections ranging from 11 to 13 degrees(19% to 23%). Up slope, west of the lots, slope angles increase slightly to range from near 12 degrees to 15 degrees(approximately 2 1%to 27%). Down slope of the lots, on the east side of Blackwell Street, slopes are similar to those on the subject properties. There is no evidence of past soil movement on the lots nor was such evidence found during a reconnaissance of the general area. Vegetation on the lots is comprised primarily of mature evergreen trees with a few variously sized deciduous trees standing over a moderately dense to dense understory of mixed brush, shrubs,berry vines, grass,weeds and scrub trees. As previously noted there is no evidence of soil movement(landsliding)on the lots, with the exception of a few scattered trees, all of the trees are straight, showing no indication of rotation. The few trees of exception are scattered across the general area with the slight bowing appearing to be more the result of competition for light than ground movement. Based on mature evergreen tree breast-height-diameter and ring counts made on recently felled evergreen trees, it appears that the identifiable straight growth period ALLEN L.HART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Project No.0808031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.4 has lasted for some 80 to 150 years. If similar age to diameter ratios are used on decomposing stumps in the area this identifiable period of stability may extend to more than 250 years. The Coastal Zone Atlas of Washington,Mason County volume, indicates that the lots are located in an area where the slopes are considered to be stable with stable slopes extending away from the properties in all directions. The map "Relative Slope Stability of the Southern Hood Canal Area, Washington"indicates that the site is inside an area where the slopes are considered to be class 2 slopes with class 1 slopes lying to the west. Class 1 slopes are"Areas believed to be stable. Slopes generally less than 15%,but may be greater...underlain by very stable material such as young glacial rill...."Class 2 slopes are"Areas believed to be stable under normal conditions, but may become unstable if disturbed by man's activities, if slope is over steepened by erosion, or subjected to strong seismic sharking. Slopes generally steeper than 15%...." No active springs or seeps were observed on the site or adjacent areas during the reconnaissance of the area. Based on the soil log for a water well located on the southwest comer of Blackwell and Wade Streets, it appears that the depth to ground water in the area may be on the order of 120 feet. The log of this well is presented on Figure 9. Soil Profile and Subsurface Conditions Based on the results of my fieldwork,reconnaissance, and review of readily available maps and water well soil logs it appears that the site lies near the contact between the glacial till and the Recessional Outwash. At Test Pit 1 the Recessional Outwash is about five feet thick,however, up slope exposures indicate a possible thickness of more than six to 12 feet. The log for the well located just south of Wade Street tends to indicate an outwash thickness of perhaps four feet with a glacial till thickness approaching 30 feet. (Note: This well is approximately 25 to 30 feet above the level of Test Pit 1.) The SCS and NRCS identify the soils in the site area as primarily Alderwood gravelly sandy loam, 5%to 15% slopes(SCS and NRCS soil identification Ab)with Alderwood gravelly sandy loam, 15%to 30% slopes(SCS and NRCS soil identification Ac)lying to the west and east(up slope and down slope)of the subject lots. The SCS and NRCS indicate that the parent material for the Alderwood soils is a gravelly glacial rill. ALLEN L.HART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Project No.0808031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.5 Based on the soils exposed on and around the property, it is my opinion that the site soil conditions are generally consistent with those shown on the geologic and soil maps of the area. It is suspected that any differences between the mapped and observed soil conditions are a result of mapping scale, availability of exposures, and intended map usage. Conclusions It is my opinion that the site area does not meet the requirements of the Mason County Code, Title 8 "Environmental Policy", chapter 8.52 "Resource Management", section 8.52.140"Landslide Hazard Areas"for classification as a landslide hazard area. The site is not within an area having any indication of past or ongoing earth movement;there are no artificial over steepened or unengineered slopes;no liquefiable soils;no slopes greater than 15%intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock and with springs or ground water seepage; and, no areas with a slope of 40%or steeper and with a vertical relief of 10 or more feet...." Available slope stability maps indicate that the property is in an area generally considered to be stable. Observation of the site and adjacent areas indicates that there is no evidence past or ongoing slope soil movement(landsliding.)It is my opinion that the subject properties are not within a landslide hazard area or its associated buffer or setback. Based on my site observations and review of pertinent materials, it is my opinion that the site is located in an area of medium dense to very dense,moderately well drained to well drained soils without evidence of past or potential landslide activity. Properties in the general area with similar slope conditions have been successfully developed without consequence. It is not anticipated that construction of the single-family residences as proposed would significantly alter the present conditions to trigger landsliding which might hazard adjacent properties and/or existing residences. Similarly, the site does not appear to meet the requirements of chapter 8.52, sections 8.52.150 and 8.52.160, respectively, for classification as a seismic or erosion hazard area. Aids for Landscape Planning; Maintenance of slope vegetative can aid in slowing the overall rate of erosion and slope degradation. Although not written specifically for this type of site, the Washington State Department of Ecology has ALLEN L.)(-TART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Project No.0808031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.6 three publications, which may be helpful in developing landscape planning and longer-termed slope vegetation maintenance plans. 1. "Slope Stabilization and Erosion Control Using Vegetation: A Manual of Practice for Coastal Property Owners", May 1993, Publication 93-30. 2. "Vegetation Management: A Guide for Puget Sound Bluff Property Owners", May 1993, Publication 93-31. 3. "Surface Water and ground Water on Coastal Bluffs: A Guide for Puget Sound Property Owners", June 1995, Publication 95-107. These publications can be obtained through the Olympia office of the Department of Ecology. Additional Studies: Item vii under"Content of the Geological Assessment" asks for a recommendation whether a geological report should be required to further evaluate the site and proposed property development. It is my opinion that the site is not in an area of geologic hazard and does not meet the requirements of the Mason County Code to be defined as a landslide, erosion, or seismic hazard area. Therefore it is my opinion that no additional studies to further evaluate the site are necessary. Report Limitations This report has been prepared for the exclusive use of Drew Davies and his agents for use in development considerations on the subject properties. The conclusions in this report are based on my visual observations, interpretation of site conditions as they presently exist, and the expectation that the exploratory efforts adequately define the subsurface conditions throughout the site. The soil conditions described in this report and the conclusions and recommendations contained in this report are provided for this specific site only and should not be expanded for use on adjacent sites or properties without additional exploration and review of those sites by this firm. The results of this study are intended for the use of the original client only. Use of this report in whole or part by third parties will require a written agreement be in place between the consultant and the third-party. NOTE: Although I have reviewed subsurface conditions as part of this study, I have not conducted analytical laboratory testing of any samples obtained, have not evaluated the site for the potential presence ALLEN L.HART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Project No.0808031 Geological Assessment Allyn Block 28,Lot 4-Parcel Number 122205028004 Allyn Block 28,Lot 5-Parcel Number 122205028005 Allyn,Mason County,WA August 25,2008 Page No.7 of contaminated soil, and have not evaluated or addressed ground water conditions or concerns except as noted in this report. The owner and the contractor should make themselves aware of and become familiar with applicable local, state, and federal safety regulations, including current O.S.H.A. safety standards. Construction site safety generally is the sole responsibility of the contractor. The contractor shall also be solely responsible for the means,method, techniques, sequences, and operations of construction operations. The fmn, Allen L. Hart Engineering Geologist(including consultants and subcontractors)is providing the preceding information and recommendations solely as a service to Drew Davies. Under no circumstances should the provision of this information be construed to mean that the firm Allen L. Hart Engineering Geologist (including consultants and subcontractors)is assuming responsibility for construction site safety or the contractor's activities; such responsibility is not implied and should not be inferred. Within the limitations of scope, schedule, and budget for this work, it is warranted that the work has been done in accordance with generally accepted practices followed in this area at the time this is report was made. No other warranty, expressed or implied is made. Should you have any questions or if I may be of additional assistance, please call my office at(253) 752- 8963. a a Sincerely, at Allen L. Hart, CPG, RG/CEG, LG Licensed Engineering Geologist LLEN L. H RT ALLEN L.HART ENGINEERING GEOLOGIST 1720 North Oakes,Tacoma,Washington 98406 Virtual Earth'": 202 w 4p _ w SITE ` o' rr 70y 1 Z r-^-, �GJIV�y .Y 0416 gCrz U' F LnKCjVd V °ic.lur L 302 w �CaKis _7 £µ�J - x {v E Channg� Cmek Ito V 7 �i c W A S H I N G T O N r` ©2008 Nmneq©2008 Mcrosoft Allen L. Hart Engineering Geologist FIGURE 1-VICINITY MAP 1720 North Oakes Location: Lots 4& 5,Allyn Block 28,Mason County,Washington Tacoma,WA 98406 Job No. : 0808031 253-752-8963 Client: Drew Davies Date: 8/2008 Mason County Map Output Page Mason Count Ma W .}' C W f l Lot a44, w 4, jai (/J A. Al t Om 49M 1 t DISCLAIMER AND LIMITATION OF LIABILITY: The data used to make this map have been tested for accuracy,and every effort has been LEGEND made to ensure that these data are timely,accurate and reliable.However,Mason County makes no guarantee or warranty to its accuracy as to labeling,dimensions,or placement or RvaCS. FoCoibi lanJS location of any map features contained herein.The boundaries depicted by these data are approximate,and are not necessarily accurate to surveying or engineering standards,and are ^�ti y aY� r.dy of Shattx intended for informational purposes only.Mason County does not assume any legal liability or responsibility arising from the use of this map in a manner not intended by Mason County. ,� Rwar-$St,vrarris County WunCafv(LK4R) In no event shall Mason County be liable for direct,indirect,incidental,consequential, special,or tort damages of any kind,including,but not limited to,loss of anticipated profits �SriatS r ,,,mrn+,e,;,nhr 4agincts or benefits arising from use of or reliance on the information contained herein SA—U7,nS !at•.es 40 V 2006-Mason County Pug x Socfn;.n Major LilKOS 415 N.Sixth Street Shelton,WA 48584 Figure 2 Mason County Map Output Page Mason County Ma z 'w U s 5 r ii ! /Lot 5 y / IJ err l/ 4T w I du e 4 w�OFsr /w r' `n ti J DISCLAIMER AND LIMIT ATION OF LIABILITY: The data used to make this map have been tested for accuracy,and every effort has been LEGEND made to ensure that these data are timely,accurate and reliable.However,Mason County makes no guarantee or warranty to its accuracy as to labeling,dimensions,or placement or location of any map features contained herein.The boundaries depicted by these data areosi5 i FaQ�rat t.#ods approximate,and are not necessarily accurate to surveying or engineering standards,and are ^� asr�ay, ty o;;;rrttan intended for informational purposes only.Mason County does not assume any legal liability or responsibility arising from the use of this ma in a manner not intended by Mason County. In no event shall Mason County be liable for direct,indirect,incidental,consequential, �-r 4'vrry° 5trvamg Cuurtty Baum ary{or�a Special,or tort damages of any kind,including,but not limited to,loss of anticipated profits =a rn15 LornmfSs oar Gslocts or benefits arising from use of or reliance on the information contained herein laK.- ��2006-Mason County f s Pug*1:, 415 N.Sixth Street Tt wnSlr�s S 5onn g major L&OS Shelton,WA 98584 Figure 3 Mason County Ma a TEST PIT 4 m 1 ,t TEST PIT 3 TEST PIT 1 TEST PIT 2 J y r W AO +� Water Well-Figure 9 � �t m O si DISCLAIMER AND LIMITATION OF LIABILITY: The data used to make this map have been tested for accuracy,and every effort has been LEGEND made to ensure that these data are timely,accurate and reliable.However,Mason County makes no guarantee or warranty to its accuracy as to labeling,dimensions,or placement or go805 F�Qerat Lands location of any map features contained herein.The boundaries depicted by these data are approximate,and are not necessarily accurate to surveying or engineering standards,and are ��ti��Mra}r5 t.;ty of 6nett�n intended for informational purposes only.Mason County does not assume any legal liability or responsibility arising from the use of this map in a manner not intended by Mason County. Rwery K streams County&+unda,Ir?t1R 1 In no event shall Mason County be liable for direct,indirect,incidental,consequential, special,or tort damages of any kind,including,but not limited to,loss of anticipated profits Par yts (.�rruhi$$oMr L+stnct$ or benefits arising from use of or reliance on the information contained herein Cu 2006-Mason County h.,rt:+t 5r.:ynl B Ml;or LAPS 415 N.Sixth Street Shelton,WA 98584 Soil Log Locations Figure 4 ALLEN L. HART ENGINEERING Project No.:0808031-0808032 Log of Test Pit 1 GEOLOGIST Project:Allyn Properties 1720 North Oakes, Tacoma, WA 98406 253-752-8963 client: Drew Davies Figure: Location:See Figure 4 Elevation: SUBSURFACE PROFILE SAMPLE Remarks -6 Description a) -0 E CL a) 0) >1 Z a U) ft m Ground Surface 0 0 Gravelly SAND Brown, loose, gravelly SAND with silt to some silt, dry 2-:- Gravelly SAND 4-:- Gray with scattered tan zones, medium dense to dense, gravelly SAND with some silty zones, some minor bedding, dry. Silty gravelly SAND No ground water observed Clry. 6 Gray, very�dense, silty gravel �SAND, dry. (Glacial Terminated at 6.0 feet till) 12 10 147 16-- 18-:_ -- 20-1 6 Logged By: Excavation Method. Case excavator Datum: Excavation Date:8/14/2008 Sheet. (x I ALLEN L. HART ENGINEERING Project No.:0808031-0808032 Log of Test Pit 2 GEOLOGIST Project:Allyn Properties 1720 North Oakes, Tacoma, WA 98406 253-752-8963 Client:Drew Davies Figure: Location:See Figure 4 Elevation: SUBSURFACE PROFILE SAMPLE Remarks o Description W XZ E n E n 0 � Z H ft m Ground Surface 0 0 �. Gravelly SAND with silt L7o`ti: Brown to tan, loose to medium dense, gravely d. SAND with silt to silty, dry = SAND and GRAVEL Q. Tan, medium dense to dense, SAND and GRAVEL with silty zones and minor bedding, dry No ground water observed Gravelly SAND Bottom of exposure at 5.0 Tan, dense to very dense, gravelly SAND with feet some silt, dry. 2 8 10 1? 4 14 16 18 20 6 Logged By:ALH Excavation Method: Existing slope cut Datum: Excavation Date: 8/14/2008 Sheet: 1 of 1 ALLEN L. HART ENGINEERING Project No.:0808031-0808032 Log of Test Pit 3 GEOLOGIST Project:Allyn Properties 1720 North Oakes, Tacoma, WA 98406 253-752-8963 Client:Drew Davies Figure: Location:See Figure 4 Elevation: SUBSURFACE PROFILE SAMPLE Remarks o Description t E n a a > z H o Oft m0 Ground Surface FOREST DUFF and TOPSOIL . :. Interbedded SAND and GRAVEL : :. Tan to gray, dense to very dense, interbedded tr SAND and GRAVEL, SAND, gravelly SAND with varying in silt and pockets of till-like material, dry p:•.ice:; ??:6 8 tS ict6: 1012 v_o. No ground water observed Bottom of exposure at 12.0 feet 1,} I a 18 20 6 Logged By:ALH Excavation Method: Existing slope cut Datum: Excavation Date:8/14/2008 Sheet: �T ALLEN L. HART ENGINEERING Project No.:0808031-0808032 Log of Test Pit 4 GEOLOGIST Project:Allyn Properties 1720 North Oakes, Tacoma, WA 98406 253-752-8963 Client., Drew Davies Figure: Location:See Figure 4 Elevation: SUBSURFACE PROFILE SAMPLE Remarks _ 75 Description .n 0 t M E a Q E :3 T N T Z F— U) ft m Ground Surface 0 0 ^z FOREST DUFF and TOPSOIL a.. Interbedded SAND and GRAVEL Tan to gray, dense to very dense, interbedded SAND and GRAVEL, SAND, gravelly SAND with 0:0 varying in silt and pockets of till-like material, dry o <.. 4 ' No ground water observed -' Bottom of exposure at 6.0 2 feet . 8 10 12 1 f+ 16 18 20 6 Logged By:ALH Excavation Method: Existing slope cut Datum: Excavation Date: 8/14/2008 Sheet: 1 of 1 ) ° WATER WELL REPORT ECOLOCI' Original&f copy•Ecology,2°acopy-owner,$"h mpy•driaer CURRENT -• • Notice of Intent No.WFA8302 Construction/Decommission(x"In circle) Unique Ecology Well ID Tag No. BAR601 RI Construction Decommission ORIGINAL INSTALLATION Water Riglit Permit No.EXEMPT WELL Notice oflntentNumber Property Owner Name JEFFREY CAREY PR0P0SEDUSe p Domestic ❑ Industrial ❑Monidpal Well Street Address 171 BLACKWELL STREET ❑Dewnier El injilation ❑TeslWa,1 ❑other TYPEOFWORM Ownsesnumherafwell(ifmorethanOno) City ALLYN COUnty MASON ZNew we11 ❑Reoonditianed Method: 1]Dug El Bored ❑Drive" ❑ r h e �Ratmv ]cried Locetionh I/4-1/4 EE_1/4 Sec 20 Twn22N R IW oM Check One DIMENSIONS:Diameter of well inches,drilled 4 fl. (s,t,r Still REQUIRED) x`,%N,M E l DwW i we117 CONSTRUCTION DL'TAILS Lat/Long Lat Deg Lat Min/Sec Casing Welded 6 Oiam.f=+2 tt.in 378 ft. Deg g- Lon MinlSee lnstalled: ❑Liner installed DDi-M.from ft.to P ❑Threaded Diem.From to ft. Tax Parcel No.(Required) 122 05048009 Perforations ❑Yes i]No CONSTRUCTION OR OEC0mMISSION PROCEDURE xfanmr used Formation;Describe by o010:•chametor,size of materiol and structure,and the kind and Type of perforator SIZE ofperf in.by in.and no afperfs��from it to ft nature or,,,e ntazerial in each stratum pon.tmed,wit;,at Ieam one ettry'Iar each change afinformotion. (USE ADDITIONAL SHEETS IF NECESSARY.) 5veens: QYes IO o &K Pic L radon 375 MATERIAL FROM TO r ManufactatefcName BROWN SILTY SAND,GRAVEL 0 4 Type SLOTTED Model No. BROWN SILT BOUND SAND,GRAVEL 4 34 Diam.5 Slat sim,040 from 377 fr•a 397 fL BROWN SILTY SAND,50ME GILP.VI3L 34 53 Dism. Stet size frmn it to S3 87 GreveUFilterparked: ❑ Yes W No Size ofgravellseed BROWN FINE SILTY SAND 87 114 R GRAY MCD:UM SAND,GRAVEL Materials placed from fL to BROWN FINE TO W..E.DIUM SAND,PEA 114 Surface Seal: G Yes © No TowhUrkpth? 2ta 8 GRAVEL 127 Matmiel nsrd in sesi BENTONPTE CHIPS MEDIUM TO LARGE GRAVEL.FINE SAND 127 141 Did any strata contain unusable wooer? ❑Yes No BROWN FJNE SAND,SILT,WET 141 154 Type e,twatert Depth oi'stmta MEDIUM TO LARGE GRAVEL,SAND,WA;ER 154 157 Method afsesting strata off GRAY SANDY CLAY prITH SILT 157 199 PUMP:ManutbcturersNeme GRAY STICKY CLAY.DRY,STIFF j 189 200 Type: KP. BROWN SILTY CLAY WITH GRAVEL 200 219 WATER LEVELS.Laud-siu*te elevebon above mew sea level ft FINE SILTY BROWN SAND,WATER 219 244 Static feud 124 ft.below top ofwen Due 6/11/09 MEDIUM BROWN SAND,WATER 244 261 FINE IIROWN SAND,FEW GRAVEL,WET 26i 280 Ariasisa presstae Ihs.per squirt inch Date GRAY FINE TO Mc'DJUM SAND, 1 280 Artetiatt wow is controlled by (trP='�v4am) OCCASSONAL GRAVEL,WET 293 WELL TESTS:Dn wdowo is amount water level is lowered bclaw static level (}RAY CLAY,STIFF,DRY 1293 295 Was a pomp testrnsde? M Y. [,No Ifyes,bywharn? A DI REDJSHBROWNPEAT 295 299 Yield: 75 gal lmin.with ft.draw'down atha hrs. GRAY CLAY 299 - 305 Yield:4 aalAnin with R-ft drawdown after 1:a GREEN CLAY 299 305 Yield gslhnin.with =It.drnwdown attar=hrs. 305 Recongy data i'dme raAm aszero when pump l rned oM(w0tukrAme0AMrd fr=KmO GRAY CLAY 308 312 top to wow Irmo GRAY FINE TO MEDIUM SAND,GRAVEL 1312 Tirm Water Level Time Wj=Level Time WaterLevol WATER 320 GRAY SILTY CLAY,FEW GRAVEL 320 338 BROWN SILTY SAND,FEW GRAVEL,WATER 1338 348 MEDIUM TO LARGE MEDIUM BROWN 348 Date of test SAND,WATER 380 Dm'IarTesi 20 Ihn...with 4 8.dmwdo..a. 4 lus. MEDIUM SAND,SOML GRAVEL,WATER 380 400 Airiest gaVtrrin.with stem set at R.for his. Artesian flow &p•m.Date 6/11/08 Ta tm nperaa ofwater Was a chanical analysis made? ❑Yea [ONO Start Date 6/2/08 Completed Date WELL CONSTRUCTION CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its eompliance Wiifh all Washington well coustmetion standards.Materials used and the nlformation reported above are true to Iny best knowledge and belief. ❑D11l)er[3EnginewGITrainee Narne( ' HUAKOEPP _ DrillingCorMany ARCADIA DRILLING INC. Driller/Enginwrfr rinee Signature Address PO BOX 1790 Driller or trainee License No. 287 City,state,Zip SHELTON WA 98594 IF TRAINEE:Drillees Li-e No: Contractor's Drilkes Sigrtaitu= Registration No, ARCADDI098IC1 Daze 6/16/08 ECP 050-1-20(Rev 06 IR)Ifyoer need this domanent to on altenate fo-MOF,Please aall the Water ResmoTes Program at 360-407-6600. Petanns lvi8i heating loss can ca11711 for Waddirgion Rday Snvlcx Persons u itlr a speech disability can call 877-8334M]. Figure 9 Soil Map—Mason County,Washington $ 512500 51 512700 512800 512900 513000 513100An _ n AW N N �e • O h r F N t � N \ O i - S = 1 0 I a N 1 g w o 0 N � h 51 51 51 51 5400 513000 513100 Meters N 0 50 100 200 300 A Feet 0 250 500 1,000 1,500 MA Natural Resources Web Soil Survey 2.0 Figure 10 Conservation Service National Cooperative Soil Survey Soil Map—Mason County,Washington MAP LEGEND MAP INFORMATION Area of Interest(AOI) fN Very Stony Spot Original soil survey map sheets were prepared at publication scale. Area of Interest(AOI) Viewing scale and printing scale,however,may vary from the Wet Spot original.Please rely on the bar scale on each map sheet for proper Solis A Other map measurements. Soil Map Units Special Line Features Source of Map: Natural Resources Conservation Service Special Point Features Gully Web Soil Survey URL: http://websoilsurvey.nres,usda.gov Blowout Coordinate System: UTM Zone ION Short Steep Slope ® Borrow Pit This product is generated from the USDA-NRCS certified data as of Other the version date(s)listed below. X Clay Spot Political Features Soil Survey Area: Mason County,Washington 6 Closed Depression Municipalities Survey Area Data: Version 4,Dec 5,2006 y, Gravel Pit Cities Date(s)aerial images were photographed: 6121/1990 Gravelly Spot ❑ Urban Areas The orthophoto or other base map on which the soil lines were Landfill water Features compiled and digitized probably differs from the background p Lava Flow Oceans imagery displayed on these maps.As a result,some minor shifting of map unit boundaries may be evident. Marsh Streams and Canals R Mine or Quarry Transportation d r+ Rails * Miscellaneous Water Roads pp Perennial Water Interstate Highways v Rock Outcrop US Routes t Saline Spot State Highways Sandy Spot N Local Roads Severely Eroded Spot Other Roads p Sinkhole Slide or Slip 0 Sodic Spot Spoil Area Stony Spot Natural Resources Web Soil Survey 2.0 Figure 11 Conservation Service National Cooperative Soil Survey Soil Map-Mason County,Washington Map Unit Legend • Mason County,Washington(WA645) Map Unit Symbol Map Unit Name Acres In AOI Percent of AOI Ab Alderwood gravelly sandy loam, 47.7 53.0%1 5 to 15 percent slopes Ac Alderwood gravely sandy loam, 27.7 30.8% 15 to 30 percent slopes Ee Everett gravely loamy sand,5 - 0.0 0.1% to 15 percent slopes Mc McKenna gravelly loam,0 to 3 8.8 9.8% percent slopes — so Sinclair shoty loam,5 to 15 5.6 6.3% percent slopes 100.0% Totals for Area of interest(AOI) 89.9 - _._ --- _-- Natural Resources Web Soil Survey 2.0 Figure 12 Conservation Service National Cooperative Soil Survey MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Division P O Box 279, Shelton, WA 98584 flo (360)427-9670 Geotechnical Assessment Review Acceptance Letter March 17, 2011 DREW DAVIES P O BOX 1095 ALLYN WA 98524 Case No.: GE02011-00016 Parcel No.: 122205028004 Proiect Description: GEO ASSESSMENT SUBMITTED FOR SFR, (SEE BLD2011-00135) The Geotechnical Assessment for DREW DAVIES has been received and reviewed by the Planning Department. The assessment was prepared by Allen Hart dated 8/25/2008. Based on the certification provided by the licensed engineer/geologist, the referenced Geological Assessment was prepared in general accordance with the requirements in the Mason County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.4. Mason County considers the review valid until such time as scope of project, site conditions, and/or regulations change. Should the scope of work, site conditions, and/or regulations change after the original review, then an addendum from the original author of the assessment may be required to address these changes. The assessment would only be re-reviewed if a permit for development were submitted after these changes occur. Mason County does not certify the quality of the work done in this Geological Assessment. Please contact me at (360) 427-9670, ext. 365 if you have questions. Sincere Allan Borden Land Use Planner Mason County Planning Department Comments: 3/17/2011 Page 1 of 1 GE02011-00016 i 0 Li: KEPT IN 71-1E Coe7r�" (,L ' IVlPon County Review Checklist ARCE, c ` i 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#_ + Parcel# � Ur G CJ Date(s)of the Document(s) reviewed: (1) A discussion of geologic conditions in the general vicinity of the proposed dev lopment,with geologic unit designation based on referenc d maps. OK?_V Comment: 1 -3 . q (2) (a)A discu ion of the gro nd water con i 'on at the site, OK?Comment: (b) A discussion of the estimated dept to wate OK? Comment: (c) A discussion of the quantity of surfaces page OK? C/ Comment:' A Y (d) A disci lion of the upslope geomorpholo OK? Comment:. P4 3 (e) A discus n of location of upland wate a and vyexl nds. OK?�mment: j llf/ (3) The ap imate depth to hard or dense m etent soil,e.g. glacial till or outwash sand. OK? Comment: (4) A discus ion of any geomorphic exprbssion of past slope instability(presence of hummocky ground or ground cracks,terraced topography indicative of landslide block movemen owed or arched trees indicpting downslope movement, etc.). OK? Comment: LV& (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 de elopment 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 w ether a Geotechnical Report should be required to further v luate site conditions and the proposed development of the subject property. OK. Comment: 17A1 6 (8) If the presence of a hazard is dete min d within 300 feet of the proposed development, then the following are delineated on a geologic map/site map: (a) the are of the proposed development, OK? Comment: N Page 1 of 2 Form Effective June 2008 (b) the boundaries of the landslide hazard area(top, both sides, and toe), OK? Comment: 2 (c) the associated buffers (top, both sides, and toe ` OK? Comment: A (d) building or other setbacks (top, both sides, and toe). OK? Comment: AL (9) A site map drawn to scale showing the property boundar s, scale, north arrow, and the location an nature of existing and sed d velop nt on the site. OK. Comment: l Are the.Document(s)signed and stamped?�_. _ p� Type and#of License: If not approved, what is the next action/recommendation for further action. - -/ Reviewed by , on Time spent in review: SECOND REVIEW/.UPDATE: . . Reviewed by , on Time spent in second review: THIRD REVIEW/UPDATE: 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 i i Mason County Department of CommunitV Development Submittal Checklist For a Geological Assessment I i Instructions: i 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. i I Applicant/Owner_Drew Davies Parcel#122�205028004 and 122205028005 i i Site Address Not assigned ! I (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)_3&4 (2) (a)A discussion of the ground water conditions at the site, Located on page(s) 4 i (b) A discussion of the estimated depth to water Located on page(s)_4 ! I (c) A discussion of the quantity of surface seepage Located on page(s) 4 I (d) A discussion of the upslope geomorphology Located on page(s)_3 ! (e) A discussion of location of upland!waterbodies and wetlands. Located on page(s) NIA none on or adjacent to site (3) The approximate depth to hard or dense competent soil, e_g.glacial till or outwash sand. Located on page(s) 4 (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.). Located on page(s) I (5) A discussion of the history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 3&4 i (6) An opinion on whether the proposedldevelopment 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 Located on page(s) 5 (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 I Form Effective June 2008 i Located on page(s) 6 I (8) 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: (a) the area of the proposed development, Located on Map(s) N/A (b) the boundaries of the landslide hazard area(top, bath sides, and toe), Located on Map(s) NIA i (c) the associated buffers(top; both sides, and toe) Located on Map(s) N/A (d) building or other setbacks(top,,bothi sides,and toe).. Located on Map(s) N/A 1 (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. Located on Map(s)_Discussed on page 1, shown on attached drawing-Addendum 1 to report i I I I, Allen L Hart I 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 also certify that the Geological Assessment, dated August 25,2008. and entitled- -'Report of Soil Study and Geological Assessment, Proposed Single-Family Residence"Building Sites, Allyn Block 28, Lot 4-Parcel Number 122205028004,Allyn Block 28, Lot 5-Parcel Number 122205028005, Ally, Mason County,Washington"_meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that thIe risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated i such manner as to prevent harm to property and public health and safety. (Signa and m } 0 i f c"nglrreed Geologist r Z ALLEN L. HART I Disclaimer.Mason County does not certify the quality of the work done in this Geological Assessment- Page j 2 of 2 Form Effective June 2008. I i i �:aa�+5 iiar�n�}�elfl i E L I u L O I u t � z o to i w i C W 'a _C i � E in i ff� I � i i i ;f t I i I 1 'w' Lr) it fo Q I U O � i - X tl I a II. Q Addendum 1 To Re l ort Dated Au"- st 25 2008 AIlen L.Hart Engineering Geologist i Site Plan-Building Envelope Oakes Location:Lots 4 and 5,Allyn Block 28,Mason County,Washington Tacoma, V4 W A 9840G Sob No.: 0808031 253-752-8963 Client: Drew Davies Date• 8/2008 i i