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Home My WebLink AboutGeoTech Assessment - BLD Engineering / Geo-tech Reports - 3/12/2007 MASON COUNTY PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER Shelton, Washington 98584 DATE: March 12, 2007 INTER-DEPARTMENTAL COMMUNICATIONS TO: Chuck McCoy PARCEL # 12330-54-00023 FROM: John Sliva, Programs Engineer-PW BUILDING PERMIT NUMBER: BLD2007-00048 SUBJECT: Geo-Assessment Review NAME: Wilson Frank Chuck The Geological Assessment for the proposed garage at 111 NE Jolly Roger Lane at Belfair was received and reviewed by Public Works. The assessment notes that steepest slope on site is 26 percent. No slope instability was observed at or around the proposed building location. Even though slopes approach 26 percent onsite, the potential for landslide activity is not a concern for the proposed construction. Proposed activities and site conditions for the proposed development do not warrant a more comprehensive Geotechnical Report. The geological assessment appears to satisfactorily address County requirements for a geological assessment reporting. A geotechnical report will not be required based on the author' s comments and recommendations. Recommendations contained in the report should be incorporated into the site development plans and made conditions for permit issuance. Adequate erosion and sediment control features need to be implemented during land disturbing activities to protect neighboring properties and State waters from adverse stormwater runoff impacts. The migration or release of silty water or mud from the applicant's property will be considered a violation of County and State water quality protection regulations. Please feel free to contact me at 724 if you have any questions regarding these comments, or if you feel any features need further discussion or attention. erely, John Sliva Programs Engineer L GEOLOGICAL ASSESSMENT 111 NE JOLLY ROGER LANE BELFAIR, WASHINGTON PREPARED FOR FRANK WILSON BY GEOTECHNICAL TESTING LABORATORY OLYMPIA, WASHINGTON FEBRUARY 7, 2007 FEb ► t YC1�l� MASON COUNTY GEOTECHNICAL TESTING LABORATORY CONTACT INFORMATION PREPARER INFORMATION GTL PROJECT NUMBER: 07-0058 CONTACT: LANCE LEVINE ADDRESS: 10011 BLOMBERG STREET SOUTHWEST OLYMPIA,WASHINGTON 98512 TELEPHONE: (360)754-4612 FACSIMILE: (360)754-4848 EMAIL ADDRESS: GEOTESTLAB@COMCAST.NET CLIENT INFORMATION CLIENT: FRANK WILSON TELEPHONE: (360)275-5408 CELLULAR TELEPHONE: (360)440-2307 MAILING ADDRESS: 111 NE JOLLY ROGER LANE BELFAIR,WASHINGTON 98528 SITE ADDRESS: 111 NE JOLLY ROGER LANE BELFAIR,WASHINGTON 98528 PARCEL NUMBER: 123305400023 GPS LOCATION: N47o 26.9031 W 122°51.2851 1001 1 Blomberg Street SW,Olympia, WA 98512 2 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY SCOPE OF UNDERSTANDING FRANK WILSON 111 NE JOLLY ROGER LANE BELFAIR,WASHINGTON 98528 RE: GEOLOGICAL ASSESSMENT SITE INFORMATION: 111 NE JOLLY ROGER LANE BELFAIR,WASHINGTON 98528 GPS LOCATION: N47,26.903' W122o 51.2851 PARCEL NUMBER: 123305400023 Mr. Wilson: As per your request, we have conducted a geological assessment and analysis for the above-mentioned parcel. A site reconnaissance was performed on February 5, 2007. The results of this investigation are to be found in the following assessment. We have provided three copies for your review and distribution. We are also a full service laboratory that can meet all your building, testing (soils compaction, asphalt, concrete, resteel), and special inspection needs. We appreciate this opportunity to be of service to you and we look forward to working with you in the future. If you have any questions concerning the above items, the procedures used, or if we can be of any further assistance please call us at the phone number listed below. e 0� Was h�h fo Respectfully Submitted, GEOTECHNICAL TESTING LABORATORY *Q /4"W Engineering Geologist ,` Harold Parks, L.G.,L.E.G. 827 Senior Engineering Geologist '9Gd GO HAROLD PARKS �x vz-Es 7-31-01 10011 Blomberg Street SW,Olympia, WA 98512 3 Phone#: (360)754-4612 Fax#: (360)754-4848 I GEOTECHNICAL TESTING LABORATORY TABLE OF CONTENTS CONTACTINFORMATION.......................................................................................................................................................2 SCOPEOF UNDERSTANDING.................................................................................................................................................3 TABLEOF CONTENTS..............................................................................................................................................................4 PURPOSE........................................................................................................................................................................................5 SITECONDITIONS...........................................................................................................................................................................5 GEOLOGICCONDITIONS.................................................................................................................................................................6 GROUNDWATERCONDITIONS.........................................................................................................................................................7 DEPTHTO COMPETENT SOIL..........................................................................................................................................................7 PASTSLOPE INSTABILITY...............................................................................................................................................................8 HISTORY OF LANDSLIDE ACTIVITY................................................................................................................................................9 POTENTIAL FOR LANDSLIDE ACTIVITY...........................................................................................................................................9 RECOMMENDATIONS....................................................................................................................................................................10 VICINITYMAPSITE PLAN.............................................................................................................................................................11 SITEPLAN....................................................................................................................................................................................12 10011 Blomberg Street SW,Olympia, WA 98512 4 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY PURPOSE The objective of the geological assessment is to assess the surface and subsurface conditions prevalent at the subject site according to Mason County Critical Areas Ordinance 17.01.100.E4. We understand the parcel will be developed by constructing a single-family residence. At the proposed building location, the slope is approximately 2 percent. The steepest slope measured onsite is approximately 26 percent in the southern portion of the site. The Mason County Resource Ordinance Geologically Hazardous Areas(12-27-2006)contains the following: 17.01.100 Landslide Hazard Areas E. Special Reports 1. Applicability Category c. Development proposed within 100 feet of areas of oversteepened or otherwise potentially unstable slopes as a result of stream incision, stream bank erosion, and undercutting by wave action will require a Geotechnical Report. If the proposed development is 100 feet or more from these areas, but not more than 300 feet from them, then a Geological Assessment is required and a Geotechnical Report may be required based on findings of the assessment. The proposed building location will be over 100 feet from any landslide area. Hence, Mason County requires a geological assessment. 4�I wiwi r; .' _ Y`.,. i'f?c_ `-fit .'tie i� K`.•�c. .. '_ .a`. _ ke 9• I Saw" SITE CONDITIONS The subject site is located approximately 1.3 miles west of the center of Belfair, Washington. The parcel is located in an area of moderate residential development; see the Vicinity Map(Figure 1)following this report. The site is currently bounded by forested parcels to the western and eastern sides, a residential parcel to the south, and Jolly Roger Lane is to the north. Access occurs from the existing driveway along the northern portion of the site. The slope at the proposed building location is approximately 2 percent. The lot is mostly vegetated with mostly grasses and junipers. Surface water was not observed onsite. No slope instability was observed at or around the proposed building location. Surrounding trees are straight and vertical. 1001 1 Blomberg Street SW,Olympia, WA 98512 5 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY F GEOLOGIC CONDITIONS The Soil Survey of Mason County, Washington, USDA Soil Conservation Service(1960) has mapped the site soils as Everett gravelly loamy sand, 5 to 15 percent slopes(Ee). The survey states: This soil is similar to Everett gravelly loamy sand, 0 to 5 percent slopes, but its profile is more variable and the thicknesses of the surface soil and subsoil are slightly less. The Soil Survey of Mason County, Washington, USDA Soil Conservation Service(1960)has described the Everett gravelly loamy sand, 0 to 5 percent slopes(Ed)as: This soil occupies the smoother outwash terraces in association with other Everett Soils. It differs from the Everett gravelly sandy loam, 5 to 15 percent slopes, in that its subsurface layer is generally 2 to 3 inches thicker, the profiles is less variable; and the substratum, or underlying material is usually more stratified. ° - 1 r� The Geologic Map of Washington—Northwest Quadrant(2002)has mapped the site geology as advance outwash deposits(Qga)of continental glacial origin. The report reads: Advance outwash — Glaciofluvial sand and gravel and lacustrine clay, silt, and sand deposited during the advance of glaciers; sandy units commonly thick, well sorted, and fine grained, with interlayered coarser sand, gravel, and cobbles; locally contains nonglacial sediments and deposits mapped as transitional between glacial and nonglacial. Includes the Colvos and Esperance Sand Members of the Vashon Drift and part of the Vashon Drift undivided. 10011 Blomberg Street SW, Olympia, WA 98512 6 Phone#: (360)754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY GROUNDWATER CONDITIONS Groundwater seepage was not observed at the proposed building location or throughout the site. Wetland vegetation was not observed at the proposed building location or throughout the site. Research of the local wells indicates that depth to static groundwater is unknown at the subject site. No evidence of ponding was observed at the subject site. MR ' AVT DEPTH TO COMPETENT SOIL The building location is underlain by Vashon glacial advance material. Competent sandy gravel was observed at approximately 16 inches below the existing ground surface. 1001 1 Blomberg Street SW,Olympia,WA 98512 7 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY PAST SLOPE INSTABILITY Surrounding the subject site, trees were observed to be straight .'; and vertical. No indication of past instability was discerned at the proposed building location or throughout the site. Slumping and landsliding were not observed at or near the site. At the building location, the slope is approximately 2 percent; no signs of instability were observed. *° The Coastal Zone Atlas, Volume 9, Mason County (MA-11) maps the site as Vashon glacial till(Qvt). Foundation stability is described as "excellent." Seismic stability is described as �• ' "good." The slope stability is described as"stable." —4 •.+at 10011 Blomberg Street SW,Olympia,WA 98512 8 Phone#: (360) 754-4612 Fax#: (360) 754-4848 GEOTECHNICAL TESTING LABORATORY HISTORY OF LANDSLIDE ACTIVITY Slumping or landsliding was not observed throughout the site. At the proposed building location, the current parking area demonstrates no indication of previous landsliding. The onsite trees are straight and vertical. F , y �a t.s �_ � '�• "` �! .fir,. � �. ' _may} • -- • r ..� - . ice.. ._.� � —• POTENTIAL FOR LANDSLIDE ACTIVITY The onsite and offsite slopes are not a concern for potential landslide activity. Even though slopes approach 26 percent onsite, the potential for landslide activity is not a concern for the proposed construction. The subject site and surrounding areas are well vegetated with moderate slopes. The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback, Folger,and Niggemann(September 2004)maps the site area as having a very low to low liquefaction potential. The Site Class Map of Mason County, Washington by Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004) maps the site area as site class C to D. Site class C is a very stiff soil or soft rock and site class D is a stiff soil. The Relative Slope Stability of the Southern Hood Canal Area, Washington, (1977)describes the site area as Class 2. Class 2 is described as: Areas believed to be stable under normal conditions, but may become unstable if disturbed by man's activities, if slope is oversteepened by erosion, or if subjected to strong seismic shaking. Slopes generally steeper than 15 percent, but may be less in some areas of weak geologic materials. Includes areas underlain by: well-drained sand and gravel, mostly on valley sides that lack known slope failures;glacial till with steep slopes; and bedrock. 10011 Blomberg Street SW,Olympia,WA 98512 9 Phone#: (360) 754-4612 Fax#: (360)754-4848 GEOTECHNICAL TESTING LABORATORY J RECOMMENDATIONS There is no evidence of soil erosion or deposition onsite to suggest that the site should be included in the Erosion Hazard Area designation. Proposed activities and site conditions for the development do not warrant a more comprehensive Geotechnical Report. We recommend no further action is needed unless areas of concern are unearthed during construction or damage ensues from vegetation clearing. To minimize erosion and sedimentation,we recommend that vegetation remain or be cultivated in areas outside the building location. If there are any changes in the loads, grades, locations, configurations or types of facilities to be constructed, the conclusions and recommendations presented in this report may not be fully applicable. If such changes are made, we should be given the opportunity to review our recommendations and provide written modifications or verifications,as appropriate. Changes to the Mason County Code require our firm to revisit the subject site prior to development, if six months has elapsed,to ensure the conditions are in agreement with our original report. 10011 Blomberg Street SW,Olympia, WA 98512 10 Phone#: (360) 754-4612 Fax#: (360) 754-4848 .F a y y � '•/ ' i ��1111� \'A LTER FABRIC WTEft1AL W WIDE ROLLS USE / BRIC TO WIRER HARE RING TO ATTACHUS 2 Ge o to c h n i c a 1 / '%77(14 GAUGE WIRE / FABRIC ON EQUIVALENT z Testing , s4r U FACE /,(\ za ._._ -MAX Laboratory / 2'X'WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER / BETTER OR EQUAL ALTERNATE. MATERIAL IN S'X12'TRENCH STEEL FENCE POSTS FILTER FABRIC S" FABRIC GAUGE WIRE FABRIC OR EQUIVALENT GROUND SURFACE 5'-0' / , I PROVIDE GRAVEL ACC ILL WASHED AND ON BOTH SIDES OF FTREILTER 1 Z' FENCE FABRIC ON THE SURFACE B'MI 2'XC WOOD POSTS ALT.STEEL FENCE POSTS Geotechnical Services FILTER FABRIC FENCE NOTES: / ■ A / / / 1.FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO QA/QC Services THE LENGTHAR THE BARRIER TO AVOID USE LI JOINTS.WHEN JOINTS Testing Services ARE NECESSARY,FILTER CLOTH SMALL BE SPLICED TOGETHER ONLY AT / A SUPPORT POST WITH A MINMUM B4NCH OVERLAP AND SECURELY FASTENED AT BOTH ENDS TO THE POST. 2.POSTS SHALL O HE GROUND A D(MINIMAXIMUM OF 8 FEET APART AND DRIVEN SECURELY INTO THE GROUND(MINIMUM OF 30 INCHES), 3.A TRENCH SHALL BE EXCAVATED APPROXIMATELY BINCHES WADE AND 12 10011 Blomberg St.SW INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. Olympia,WA 98512 4,WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE Phone:(360)754-4612 LONG, THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST 1 INCH ONG,TIE WIRES OR HOG RINGS.THE WARE SHALL EXTEND INTO T Fax:(360)7544848 TRENCH A MINIMUM OF 4 INCHES AND SHALL NOT EXTEND MORE THAN% INCHES ABOVE THE ORIGINAL GROUND SURFACE. / / J �O•V OPO D EXISTING /// O�s /// /// // 5.THE STANDARD IC SHALL BE XTENDSTAPLEDORNARED Date: 02/05/2007 TO THE FENCE AND 20 INCHES OF FABRIC SHALL BE EXTENDED ��/ / / INC0TSTHE TRENCH C ABOVE HE THE FABRIC SHALL ROUNO NOT EXTEND MO RE THAN FABRIC SHALL Designed by: LL GARAGE RESIDENC EXISTING // / / NOT BE STAPLED TO THE EXI STING TREES, Drawn b LL / CATC SEPTIC y' /O / / // ,/ S.USE.THEWIRE ESHSU FILTER SUPPORT FABRIC AND CLOSER BEELIMPQSED,INSNGIS Checked by: LL DRAINFIELD / / , USED,,THE FILER FABRIC IS TFENCEMAPBE ELIMINATED,D,INSUCM A CASE,THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO TILE DWg#:02-05-07-009 POSTS WITH ALL OTHER PROWSIONS OR ABOVE NOTES APPLYING. 7 A HAS FILTERFA BE PERMANENTLYSTABILIZED IC FENCES CL NOT BE REMOVED BEFORE THE UPSLOPE / � S.FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH / / RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL.ANY / V�O REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY. VO / GENERAL EROSION CONTROL NOTES: 1. EROSION CONTROL MEASURES SHALL BE IN PLACE PRIOR TO THE V BEGINNING OF CONSTRUCTION.THE PROJECT ENGINEER AND THE COUNTY SHALL INSPECT AND APPROVE THE INSTALLATION OF EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION. 2.EROSION CONTROL MEASURES ARE NOT LIMITED TO THE ITEMS ON THIS PLAN.THE CONTRACTOR IS RESPONSIBLE FOR THE IN INSTALLATION AND FAAINTAI OF ALL EROSION CONTROL MEASURES. NO SILTATION OF EXISTING ORR PR PROPOSED DRAINAGE FACILITIES SHALL BE ALLOWED.CARE SHALL BE TAKEN TO PREVENT MIGRATION PROJECT NAME: OF SILTS TO OFF SITE PROPERTIES. 3.THE CONTRACTOR SHALL MANE GAILY SURVEILLANCE OF ALL EROSION WILSON SITE / Y CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIMS TO THE EROSION CONTROL MEASURES.THE CONTRACTOR SHALL PROVIDE 111 NE JOLLY ROGER LANE ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY gELFAIR,WASHINGTON BY THE COUNTY INSPECTOR ANDIOR THE PROJECT ENGINEER.FAILURE TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL AGAINST REQITHECONTRA TOR AND/RPROJECT RESULT IN CIVIL EOWNERGLEVIED PARCEL 123305400023 4.DURING THE WET SEASON(NOVEMBER TO MA"ALL DISTURBED SOILS O SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK EROSION 1ILc'MIFL V CONTROL MEASURES SHALL INCLUDE.BUT NOT BE LIMITED TO, Revlswns. COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WITH PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH, OR WOW CHIPS.SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS WEATHER PERMITS. 5.ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY TO MARE SURE VEGETATIVE COVERAGE M COMLETE.AREAS SWILL BE NORTH REPAIRED,RESEEDED,AND FERTILIZED AS REQUIRED. SCALE 1"=30' S.TRACKING OF SOIL OFFSITE VALL NOT BE ALLOWED.IF ANY SOIL IS TRACKED ONTO A COUNTY STREET,IT SHALL B REMOVED By THE END C.I.=10' OF THAT WORKING DAY.ANY FURTHER TRACKING OF MUD WILL THEN BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES TIRES / DATUM ASSUMED BEFORE DRIVING ON A COUNTY STREET. THIS IS NOT A SURVEY 7.NO MORE THAN SW LF OF TRENCH ON A DOWNSLOPE OF MORE THAN 5 PERCENT SHALL BE OPENED AT ONE TIME. EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES. B.TRENCH DEWATERING DEVICES SHALL BE DISCHARGED IN A MANNER THAT WILL 0 10 20 30 NOT ADVERSELY AFFECT FLOWING STREAMS.DRAINAGE SYSTEMS OR OFFSITE PROPERTIES. SCALE:finch=30 feet \ / / 10.ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING CONSTRUCTION SHALL BE PROTECTED SO THAT CONVEYANCE SYSTEM WATER WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM. 11.ALL OFFSTE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE ALL DI BE PROTECTED FROM LACTATION. I G U R E 2 12.ALL DISTURBED AREAS SHALLCONTRACTOR BE SEEDED SP SODDED UPON COMPLETION CF YWORK,THE CONTRACTOR SHALL BEE AREAS P O ENSURE THAT COMPLETE COVERAGE A THE DISTURBED AREAS IS PROVIDED d THAT GROW/ CATCH B OF THE VEGETATION IS ESTABLISHED. SITE PLAN 13.CATCH BASINS SMALL TRAP SEDIMENT OR FILTER FABRIC MUST BE / / PLACED UNDER GRATE UNTIL VEGETATION IS ESTABLISHED. 1/2 INCH MINIMUM DIAMETER STEEL ROD (STRAP)CLAMPED SECURELY TO PIPE q :: CORRUGATED TIGHTLINE 4 INCH cp /MW, MINIMUM,6 INCH SUGGESTED •., :.fir w'ti '.....i:'S:�. W. �.'•:. _..1'+1,'_ .';.;•�;":;':> ..�,;��«�w%`cam s �t TIGHTLINE ANCHORED WITH TWO, 3 FOOT REBAR LENGTHS OR BOLTS. FLARE END SECTIONQUARRY SPALL ; OR ENERGY :C ,:4_ ".s.1r"{^`� +:�.�.a4T• `a'•`' .�o.''•i-.it"s;.�r:"le•.•. DISPERSION DEVICE -:�`F' •r=:; t.• , _ r.w=:fs'= GRASS-LINED SWALE SHOULD BE A MINIMUM ONE FOOT WIDE AT THE BOTTOM AND ONE FOOT DEEP WITH A MAXIMUM SLOPE OF 5 PERCENT. MINIMUM 4 FEET LEVEL SECTION GEOTEXTILE FABRIC Geotechnical Testing Laboratory Geotechnical Services 100itBbmbergs=swOly.p FIGURE QA/QC Services Ph—a,WA 98512 Testing Services F-:(36oi 7544848 Not to scale DRAINAGE DETAILS MASON COUNTY PUBLIC WORKS WORK ORDER Permit#: C> 2,0q- T: r—; Date: 2_ 14-_b 7- Requested by: U FEB 14 2007 Authorized by: .SORB CCUIVTY MRUIC W► AS Type of Work: _ ��a-0 «� Public Works 1 employee in charge: CHARGE TO: Name: Billing Address: Phone: WORK PERFORMED: { Employee: —111 61 Date: � ��Y� .� Hours: Hourly Rate: �b k ~' Total: 3 � ACCOUNTS RECEIVABLE INFO: Billed Date: Invoice #: Amount Billed: Receipt # Date: Amount Paid: