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Home My WebLink AboutGEO2010-00025 Slope Assessment - BLD Engineering / Geo-tech Reports - 2/27/2010 T)�,D2-016 -60Z36 SLOPE ASSESSMENT PROPOSED SINGLE FAMILY RESIDENCE 101 EAST STEVES PLACE ALLYN, WA CLIENT: Attn: Mr. Steve Payson 3301 West Highway 16 Port Orchard, WA 98367 BY: N.L. OLSON AND ASSOCIATES, INC. 2453 BETHEL AVE. SE PORT ORCHARD, WA 98366 (360) 876-2284 JOB NO. 7450-10 Y R. Jp �VSy°F WAS , .A9359 oy 2 �S`s�ONAL MAY 2010 N.L. OLSON & ASSOCIATES INC. Engineering, Planning and Surveying May 24, 2010 Project Number: 7450-10 Attn: Attn: Mr. Steve Payson 3301 West Highway 16 Port Orchard, WA 98367 Subject: Slope Assessment Proposed Single Family Residence 101 East Steves Place Allyn, WA Mason County Parcel #: 122203490362 Dear Mr. Payson; This report presents the results of our site assessment for the referenced project. The assessment was done per Mason County Resource Ordinance, 17.01.100 landslide hazard areas, section E, special reports, page 6 of 15, dated December 27, 2006. NLO has included Mason County Department of Community Development Submittal Checklist for a Geological Assessment in the Appendix B of this report. We appreciate the opportunity to be of service to you on this project. If we can be of further assistance or if you have any questions regarding this project, please contact our office. Sincerely, Wesley R. Jo nson, P.E. Project Engineer P.O. Box 637.2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C.\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment.doc TABLE OF CONTENTS INTRODUCTION...................................................................................................................... 1 SITELOCATION....................................................................................................................... 1 SITECONDITIONS.................................................................................................................... 1 PROPOSEDDEVELOPMENT...................................................................................................... 1 FIELDINVESTIGATION.............................................................................................................. 1 SiteSoil Conditions............................................................................................................ 2 Groundwater...................................................................................................................... 2 AVAILABLE GEOLOGIC SOILS INFORMATION .............................................................................. 2 DEPARTMENT OF ECOLOGY WATER WELL REPORT................................................................... 2 SLOPERECONNAISANCE ......................................................................................................... 2 HISTORICAL LANDSLIDE RESEARCH.......................................................................................... 2 UPSLOPE GEOMORPHOLOGY................................................................................................... 3 UPLANDWATER BODIES.......................................................................................................... 3 WETLANDS............................................................................................................................. 3 CONCLUSIONS AND RECOMMONDATIONS ........................................................................4 REPORTLIMITATIONS...........................................................................................................4 VICINITYMAP...........................................................................................................FIGURE 1 SITESKETCH............................................................................................................FIGURE 2 CROSSSECTION A-A...............................................................................................FIGURE 3 SLOPE STABILITY MAP...........................................................................................FIGURE 4 APPENDIX A—TEST PIT LOGS APPENDIX B —MASON COUNTY DEPARTMENT OF COMMUNITY DEVELOPMENT SUBMITTAL CHECKLIST SLOPE ASSESSMENT PROPOSED SINGLE FAMILY RESIDENCE 101 EAST STEVES PLACE ALLYN, WA INTRODUCTION This report presents the results of our fieldwork for the referenced project. In the following, we present our findings and conclusion of our Geologic Assessment. SITE LOCATION The property is located at the address of 101 East Steves Place, Allyn, WA and by Section 20, Township 22 North, Range 01 West, Mason County, Washington. The Vicinity Map for the property has been illustrated on Figure 1. SITE CONDITIONS The site is bordered by undeveloped land to the west and north, to the south by a single family residence and beyond by State Route 3. The roughly 1.4 acres property has been previously developed with a single-family residence. We have shown the existing building and site layout on the Site Sketch, Figure 2. The site's topography consists of a relatively level area, less than 15 percent, in the area of the existing single-family residence and in the area proposed of the new addition. Beyond the existing residence to the north the slope trends up with slopes of 10 to 15 percent. The slope increases in steepness as it descends south of the existing residence with gradients of about 20 to 30 percent. Localized steeper slopes of about 80 percent were observed about 100 feet south of the proposed addition. The overall slope height was roughly 50 feet as measured above the access road and proposed finish floor elevation of the new addition. We have shown the slope profile on Cross Section A-A, Figure 3. Vegetation in the developed potions of the site consists of lawn and landscaping. The slope areas were vegetated with Douglas fir, brush, cedar, madrona, and large leaf maple. PROPOSED DEVELOPMENT As presently conceived, a new addition will be constructed along the west side of the existing single-family residence. The structure will be of light wood frame construction with a footprint of roughly 325 square feet. We have shown the proposed building area on the Site Sketch, Figure 2 and Cross Section, Figure 3. FIELD INVESTIGATION The site's subsurface conditions were explored on May 10, 2010 by excavating two test pits. The test pits were extended down 3 to 5 feet below current site grades. The test pit locations P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment.doc Project No. 7450-10 May 24, 2010 Page No. 2 are shown on the Site Sketch, Figure 2. Further discussion of the test pit excavation is provided in the following section. Site Soil Conditions In general, our test pits revealed dense to very dense glacial till below the new addition and underlying slope area. The glacial till was encountered about one foot below present site grades in the area of the new addition and about 4 feet below current site grades south of the existing residence. The test pit locations are shown on the Site Sketch, Figure 2. For a more detailed description of the subsurface investigation, please refer to Appendix A. Groundwater During our subsurface exploration, perched groundwater and standing water conditions were not encountered. However, horizontal groundwater seepage may occur above the level of the glacial till during the winter time rainy season. AVAILABLE GEOLOGIC SOILS INFORMATION The Washington Division of Geology and Earth Resource (WDGER), Geologic Map of Washington — Northwest Quadrant, dated 2002, has mapped the site as Quanternary sediments, dominantly glacial drift and includes alluvium. Glacial till consists of an unsorted, unstratified, highly compacted mixture of clay, silt, sand, gravel and boulders deposited by glacial ice. DEPARTMENT OF ECOLOGY WATER WELL REPORT A water well log located at the address of East 17991 HWY 3, Allyn WA; Mason County Parcel Number: 122203490151, indicates a static groundwater level 63 feet below the approximate level of the access road reflected on our Cross Section A-A, Figure 3. The property the well was drilled on is located down slope southeast of the subject property. Based on a water well report drilled near the property, we anticipate the glacial till extends 55 to 60 feet below our test pit excavation. The water well log was from State of Washington, Water Well Reports drilled by Davis Drilling dated April 1994. SLOPE RECONNAISANCE As part of our fieldwork, the slope areas comprising the areas both on an off the propoerty were examined for indications of instability. Indications of slope instability include head scarps, hummocky terrain, inconsistent patterns of vegetation, tension cracks, seepage zones and course grain material overlaying silt and clay soils. At the time of our slope reconnaissance on May 10, 2010, the slope areas south of the new addition appears stable. HISTORICAL LANDSLIDE RESEARCH A review of "Relative Slope Stability of Southern Hood Canal Area, WA, 1977" USGS Miscellaneous Investigation Series indicates the area in and around the property has been classified as Class 1, Class 2 and Class 3. Discussion of each class is provided in the following and the Slope Stability Mapping for the site has been illustrated on Figure 4. P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment doc Project No. 7450-10 May 24,2010 Pa e No 3 Class 1: Areas believed to be stable, generally less than 15 percent, but may be greater locally in areas too small to be shown at the map scale. Largely comprises rolling uplands underlain by stable material such as glacial till, mantled in places by a thin layer of sandy gravel or other permeable material; also includes flood plains, deltas, alluvial fans, and some beach deposits. Class 1 areas immediately adjacent to steep slopes of class 3 areas may be threatened by potential landsliding. Normal, proper engineering practices generally are adequate to insure stability in these areas. Class 2: Areas believed to be stable under normal conditions, but may become unstable if disturbed by man activities, if slope is over steepened by erosion, or subjected to strong seismic shacking. Slope generally steeper than 15 percent, but may be less in some areas of weak geologic material. Includes area underlain by: well-drained sand and gravel, mostly on valley sides that lack known slope failures; glacial retreat with steep slopes; and bedrock. Class 3: Areas inferred to be unstable because slopes, generally greater than 15 percent, and underlain by weak, unstable materials in which old or recently active landslides have occurred. Includes areas of sand and gravel on top of impermeable silt and clay, mostly along steep valley sides. The "Relative Slope Stability of Southern Hood Canal Area, WA, 1977" indicates the area of proposed development has been classified as Class 1 or Class 2. The areas designated as Class 3 reside roughly 750 or more yards southwest of the proposed new addition. UPSLOPE GEOMORPHOLOGY According to Eric J. Schuster's, "Geologic Map of Washington State", the site and its surrounding geologic nature are classified as Pleistocene Continental Glacial Drift (Qgd). The unique geomorphology of this area shows signs of glacial scouring in generally a northeast- southwest direction. These trending ridges and valleys were carved by the retreat of glacial ice in the Pleistocene (approximately 10,000 to 12,000 years ago to the end of the Epoch). During the retreat and melting of the glacial ice, the scoured areas and closed depressions were filled with outwash material (alluvium). Alluvium consists of glacial fluvial sediments, such as sand and gravel that are deposited near the terminus of the glacier in a size-sorted manner (fines up sequence). UPLAND WATER BODIES The closest upland water body is Lake Anderson a distance of about '/2 mile to the northwest. In our opinion, based on the lake being up slope of the property, we do not anticipate the proposed construction will influence this upland water body. WETLANDS The wetland mapping indicates Sherwood Creek is approximately 300 feet to the southwest and saltwater shoreline resides 450 feet south of the proposed development. In our opinion, surface runoff generated by the new addition, an impervious area of about 325 square feet (sf), will be intercepted by drainage ditches upslope of the wetland areas by either State Route 3 or East Sherwood Creek Road in the unlikely event any surface runoff from the proposed development should ever occur. In our opinion, NLO does not anticipate that the proposed new P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C:\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment.doc Project No. 7450-10 May 24, 2010 Page No.4 addition will impact wetland areas located down slope. No other documented wetland areas are noted in the general vicinity of the property. CONCLUSIONS AND RECOMMONDATIONS Following our review of Mason County Resource Ordinance, Ordinance Number 77-93, we conclude that large scale sliding or deep-seated rotational failures resulting from the proposed construction appears negligible. The overall global stability of the property under the present site conditions appears good. Based on the encountered glacial till soil conditions and the current distance the new addition is from any steep slope area, in our opinion, an additional geotechnical engineering report will not be required. REPORT LIMITATIONS This report has been prepared for the client regarding the subject project. Information presented in this report has been collected and interpreted in a manner consistent with the level of care and skill ordinarily exercised by members of the profession currently practicing under similar conditions, and in accordance with sound and generally accepted principles consistent with normal consulting practice. No other warranty, expressed or implied, including (but not limited to) any warranty or merchantability or fitness for a particular use has been made. In the event that change in the nature, design, or location of the proposed construction is made, or any physical changes to the site occur, recommendations are not be considered valid unless the changes are reviewed by NLO and conclusions of this report are modified or verified in writing. Any site involving sloping terrain has inherent risk of earth movement. As a result, the CLIENT agrees to accept full responsibility for all risks associated with steep slopes. The CLIENT acknowledges that this risk cannot be completely eliminated and that engineering and geologic analysis is intended to reduce the inherent risk associated with slopes. No amount of geotechnical engineering and geologic analysis can provide a guarantee of stable slopes. Geotechnical engineering and geologic analysis are based heavily on subjective interpretation, professional judgment, and opinion regarding the physical conditions at a specific site. Subsurface conditions are only documented at those points where samples were taken and interpolation and extrapolation is necessary between and around sample locations. Conditions can vary between samples and can change over time due to natural processes and/or human activity. Analyses and recommendations provided in this report are based in part upon the data obtained from the subsurface explorations. P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 Q\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment.doc , n• ill ��1 �• _ , :_ - ��'1"ii _ `• � -�' No Scale i J i - Y ALI J X� 3 _ •I f - _ - /a Y:tke r"•"!a� � � I e } � 3 =j Situ 60 } r�r� y�.: a.,•i. ® ®• ,- ` _ I Vicinity Map Developed From Department Of Ecology Water Well Log Information. FIGURE 1 �► 3 �� VICINITY MAP FOR: SCALE: NONE i-PA N.L.Olson&Associates,lnc. 101 EAST STEVES PLACE MR.STEVE PAYSON DATE: 6r=10 Engineering, Planning and Surveying 4°a�Q ..�° p`� 3301 WEST HIGHWAY 16 DRAWING NUMBER (360) 876-2284 9s10N1L S ALLYN, VITA PORT ORCHARD,WA 7450-10 2453 Bethel Avenue,P.O.Box 637,Pat Orchard,WA 96366 _ \ EXISTG. RESIDENCE wA.TER 1 LOT 2 POWER / WELL 2 /Z'�z RADIUS59 ;,,,• +52 j�4 26� ' & �/ \ \ N. iz +13'4• +,5,3• I / / LOT B PROPOMAxv I L x'l. uxa qG +13'7' TP-1n EXIS / *1700 LRESI / + +" L TP=j �7�fPRlDCA,10N(1YPICAL) {, \ 6 /s S N.BAY SEWER CONN. SCALE 'O' REFERENCE 1 inch = 30 feet P SITE PLAN DEVELOPED FROM DRAWING PROVIDED BY CLEINT. R.Jqy W REVISIONS er w1E A a z FIGURE 2-SITE SKETCH FOR: Mr.STEVE PAYSON " i15 9"D" NO.IDATE 9Y DESGePnON L:,N.L.Olson&Associates,Inc. �r LOT B-SHORT PLAT#2456 3301 WEST HIGHWAY 16 Doha""A'°'° Engineering,Planning One Sury*g s 101 EAST STEVES PLACE,ALLYN,WA Port Orchard,WA 98367 uo0 AraRO�vm (360)"'�M4 PARCEL#:122203490362 AOMPM H9 I"b PA Y A1.M 41brN EXISTING BUILDING PROPOSED ADDITION an �e 2o'/0 S1or:...^ OBSERVED aqp-p GLACIALTILLI GLACIAL LL w Access Drive SR 3 20 0 20 40 tb 80 100 120 14 1so 1!0 200 SCALE 1 inch=20 feet (LOOKING WEST) CROSS SECTION A-A DURING OUR RECONNAISANCE,A LIMITED SLOPE SURVEY WAS PERFORMED UTILIZING A HAND HELD (SUNTO TYPE PM-51360C)TO ESTIMATE SLOPE GRADIENTS AND A 300 FOOT FIBERGLASS TAPE WAS UTILIZED FOR SLOPE DISTANCE MEASUREMENTS.THE SURVEY SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED AND METHODS USED. REVISIONS .>• w1E ,, FIGURE 3-CROSS SECTION A-A FOR: Mr.STEVE PAYSON N0. WE By otscwl n vemom Lt,N.L.Olson&Associotes,Inc. LOT B-SHORT PLAT#2456 3301 WEST HIGHWAY 16 -DAM-MyA.MO E^9h 9 po^^h9 a^a s�Kr^s 101 EAST STEVES PLACE,ALLYN,WA Port Orchard,WA98367 �10 �^ r'e0)976'72°` PARCEL#:122203490362 ACW,m N67 tl1+we..m a m,ran aaan r um ScA L& 1 u.r� to 5y tF—34va'->I .it•Il / 'ice 3 Ic'.rC�H - 1 •v` .�•�' ` IRAsILI I, l; Stretch �. t Tit LAI �,�,laz;�;� t�; trSorck2CC�S' �U:�� `� Ce°� 1 gonr ?e J �r APPENDIX A The site's subsurface conditions were explored on May 10, 2010 by excavating two test pits. The test pits were extended down 3 to 5 feet below current site grades. In general, our test pit revealed the area between the slope and proposed new addition was underlain by dense to very dense glacial till. The depth of the till was about one foot below the new addition and about 4 feet below current site grades south of the residence near the top portion of the slope. The test pit location is shown on the Site Sketch, Figure 2. The test pit logs have been included in this appendix. The subsurface exploration logs and related information depicts conditions only at the specific locations and at the particular time designated on the logs. The passage of time may result in a change of subsurface conditions at these exploration locations. Subsurface conditions at other locations may differ from conditions occurring at the exploration locations. The nature and extent of variations of subsurface conditions between explorations are not known. If variations appear during additional explorations or construction, re-evaluation of recommendations in this report may be necessary. P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment doc Test Pit Log A'-`A N.L.Olson&Associates,Inc. Mr. STEVE PAYSON Engineering, Planning and Surveying 2453 BETHEL AVENUE 3301 WEST HIGHWAY 16 P.O.BOX 637 PORT ORCHARD, WA PORT ORCHARD,WASHINGTON 98366-0637 Job Number Logged By: I Subsurface Exploration Ground Surface Elevation Test Pit Number Page 7450-10 WRJ Star5//10/2010 End5/10/2010 80 TP-1 1 of 1 Surface Conditions: General Notes F n USCS t Moisture Sample Collected �;�, svMeoL contert Gravel Parking Area SM Brownish Gray Silty SAND with gravel and cobbles trace boulders, dense, 1 moist, — - - - - Grades to gray at one (1) foot and becomes very dense- Glacial Till SM 2- 3-- End of Test Pit 3 ft bgs 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Contractor Operators Name Sampling Method Drawn By: Date Test Pit Completion Sundance Steve Payson Grab VVRJ 5/26/2010 ❑ Monitoring Well Equipment Groundwater Elevation Checked By: Date ❑ Piezometer Small Trackhoe None WRJ ® Abanonded and backfilled LOCATION: Revision By. Date ❑ 101 EAST STEVES PLACE ERC ❑ ALLYN,WA ❑ A Test Pit Log k-,'A N.L.Olson&Associates,Inc. Mr. STEVE PAYSON •• Engineering, Planning and Surveying 2453 BETHEL AVENUE 3301 WEST HIGHWAY 16 P.O.BOX 637 PORT ORCHARD, WA PORT ORCHARD,WASHINGTON 98366-0637 Job Number Logged By: Subsurface Exploration Ground Surface Elevation Test Pit Number Page Date 7450-10 WRJ kta 5/101201 End5/10/2010 -70 TP-2 1 of 1 Surface Conditions General Notes La$ USCS t Moisture Sample Collected N SYMBOL iu Content Gravel Parking Area 0 (%) Dark Brownish Gray Silty SAND with gravel and cobbles, medium dense, SM 1 moist, 2 3 4 S M — — — — — — — — — — — — — - Grades to gray at four(4) feet and becomes very dense- Glacial Till 5 End of Test Pit 5 ft bgs 6 7 8 9 10 11 12 13 14 15 16 17 18 Contractor Operators Name Sampling Method Drawn By: Date Test Pit Completion Sundance Steve Payson Grab WRJ 5/26/2010 ❑ Monitoring Well Equipment Groundwater Elevation Checked By: Date Piezometer Small Trackhoe None WRJ ® Abanonded and backfilled LOCATION. Revision By Date ❑ 101 EAST STEVES PLACE ERC ❑ ALLYN,WA ❑ r 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:_�:::&�4�1& Permit# 4,D W , �o 2116 Parcel # 3 Lf CID 36 y-, . 1 Q ' 00(11,� Date(s)of the ocument(s)reviewed: Z (1) A discussion of geologic conditions in the general vicinity of the proposed development,with geologic unit designation based on referen d maps. OK?Comment: (2) (a)A disc sion of the ground water conditions at the site, OK? - Comment: (b) A discussion of the estimated depth to water OK?_Comment: (c) A disc sion 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 appro imate 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 owed or arched trees indicating downslope movement, etc.). OK?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 oplii6n 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 propose,d development. OK? Comment: (7) A reco endation by the preparer whether a Geotechnical Report should be required to further evaluate site conditions and the proposed 5evelopment of the subject property. OK? e �Comment: (8) If the prbs nce of a hazard is dete mined within 300 feet of the proposed development, then the following are delineated on a geologic map/site map: (a) the area of the proposed del vpl^op ent,r1 OK? Comment: � /� [ Page 1 of 2 Form Effective June 2008 (b) the boundaries of the landslide azard area (top both sides, and toe), OK? Comment: 1,�1.1 (c) the associated buffers (top, both sides,i nd toe�/ OK? Comment: I"�'� ' `�JA. (d) building or other setbacks (t p, bop sid s, an to OK? Comment: �v (9) A site map drawn to scale showing' e property boundaries, scale, north arrow, and the location and nature of sting and pioposed development on the site. OK? Comment: nzy Are the Document(s)signed and stamped? r �. Type and #of License: - 3 q , l/!f f If not approved, what is the next action/recommendation for further action? ke, 6 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 (b) the boundaries of the landslide azard area to both sides, and toe), OK? Comment: �/� (c) the associated buffers (t p, both sides,pnd toe / OK? Comment: r V jA (d) building or other setbacks (t p, bo)h sid s, anc�toG) OK? Comment: (9) A site map drawn to scale showing e property boundaries, scale, north arrow, and the location and nature of sting and pyoposed develop exit on the site. OK? Comment: Are the.Document(s) signed and stamped? Type and #of License: 3 W C41 � 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 From: Allan Borden To: town&county homesE=e(�> Date: 9/4/2015 2:59 PM Subject: geo study for review of BLD2015-00652 on parcel 12220-34-90363 Attachments: Payson geo assessment 2010 study.pdf Dawn / Town & County Buildings: As requested, I scanned the permit copy of a geologic assessment prepared by N.L. Olson & Associates in 2010 for the home addition on the parcel to the east of the property where a new garage is now proposed under the above-noted permit. What is requested is an update of the 2010 study that addresses any site changes or property conditions that would affect the construction of the proposed garage building (such as slides, slumping vegetation, excavations, or new wall structures). Submit the new study to the Permit Assistance Center 426 West Cedar St. Shelton WA 98584. Allan Borden Planner - Long Range & Site Inspection 426 W. Cedar St., Shelton, WA 98584 (360) 427-9670 ext. 365 APPENDIX B 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. Applicant/Owner: Mr. Steve Paxson Parcel# 122203490362 Site Address 101 East Steves Place, Allyn, WA (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) 2 & 3 (2) (a) A discussion of the ground water conditions at the site. Located on page(s) 2 (b) A discussion of the estimate depth to water Located on page(s)2 (c) A discussion of the quantity of surface seepage Located on page(s) 2 (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)3 (3) The approximate depth to hard or dense competent soil, e.g. glacial till or outwash sand. Located on page(s) 9- (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) 2 (5) A discussion of the history of landslide activity in the vicinity, as available in the referenced maps and records. Located on page(s) 2 (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. Located on page(s) 4 (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. Located on page(s) 4 (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— No Hazards Noted (b) The boundaries of the landslide hazard area (top, both sides, and toe), Located on Map(s) N/A— No Hazards Noted (c.) The associated buffers (top, both sides, and toe) Located on Map(s) N/A— No Hazards Noted (c) Building or other setbacks (top, both sides, and toe). Located on Map(s) N/A—No Hazards Noted (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) See Figure 2 P.O. Box 637. 2453 Bethel Avenue • Port Orchard, Washington 98366 Phone: 1(800) 755-1282 Fax: (360) 876-1487 C\Documents and Settings\WJohnson\My Documents\Project Folder\7450 Payson Slope\Payson Slope Assessment doc I EXISTING BUILDING t0 PROPOS D ADDITION 80 le 2Q% Slop ang �g 6D S o OBSERVED �`a GLACIAL T LL GLACIAL TILL O� 40 ALONG R Access rive SR 3 20 0 20 40 60 80 100 120 140 160 180 200 220 240 260 SCALE 1 inch = 20 feet (LOOKING WEST) CROSS SECTION A-A DURING OUR RECONNAISANCE,A LIMITED SLOPE SURVEY WAS PERFORMED UTILIZING A HAND HELD (SUNTO TYPE PM-5/360C)TO ESTIMATE SLOPE GRADIENTS AND A 300 FOOT FIBERGLASS TAPE WAS UTILIZED FOR SLOPE DISTANCE MEASUREMENTS. THE SURVEY SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED AND METHODS USED. BY DATE 3 ° 2 FIGURE 3- CROSS SECTION A-A FOR' Mr.STEVE PAYSON SCALE: AS SHOW REVISIONS DATE:NAY24, 2010 DESIGNED A NO. DATE BY DESCRIPTION `•k N.L.Ol son&Associates,lnc. t� LOT B - SHORT PLAT#2456 3301 WEST HIGHWAY 16 JOB NUMBER DRAWN CHECKED Engineering, Planning and Surveying ,�tr„9% 101 EAST STEVES PLACE, ALLYN, WA Port Orchard,WA 98367 7450-10 ��ONAL APPROVED (360) 876-2284 PARCEL#: 122203490362 ACCEPTED 2453 Bethel Avenue,P.O.Bo:637,Port Orchard,WA 96366 SHEET I OFI ow-m _ EXISTG. RESIDENCE LOT 2 / POWER +5 9" Jl / WELL gg,�3' / / /DER/ //-- o , ��F,C' RADIUS M/ SEMEN R /A- +1'10" +13'4" }�3 L� / ' LOT B -6 o 4 I z PROPOSEDADDN k� �j 12 X 27 U +13'7" LF TP-1 z �6 EXISTING / �- 1700sf RESIDENCE I +13' �_ TP-� NEST PIT LOCATION(TYPICAL) 2 1st N,BAY SEWER C❑NN, SCALE 0' REFERENCE 1 inch = 30 feet P SITE PLAN DEVELOPED FROM DRAWING PROVIDED BY CLEINT. C'J�4��' rRL eA1G lR-AII 9[".Y[ REVISIONS BY DATE FIGURE 2 - SITE SKETCH FOR: Mr.STEVE PAYSON SCALE: AS-WOW DESIGNED L_Pj N.L.Olson&Associotes,inc. LOT B - SHORT PLAT#2456 3301 WEST HIGHWAY 16 DAre:MAY2<, ?010 N0. DATE BY DESCRIPTION JOB NUMBER DRAWN Engineering, Planning and Surveying ��e°""�e+` 101 EAST STEVES PLACE, ALLYN, WA Port orchard,WA 98367 JOB NUMBER CHECKED J10AA1 APPROVED cab°' 878-2284 PARCEL#: 122203490362 ACCEPTED 2453 Bethel Avenue,P.O.Box 637,Port Orchard,WA 96366 1 a 0 1 SHEET 1 F 1