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HomeMy WebLinkAbout992600020 Geotech AssessmentGary A. Flowers, PLLC Geological & Geotechnical Consulting 1953212th Avenue NE Shoreline, WA 98155-1106 September 13, 2007 Project No. 07034 Jeff & Julianne Schmidt 1428 Decatur Ave Bremerton, WA 98337 Subject: Proposed New Single 7583 Tharndyke Road Quilcene, Jefferson Cc Tax Parcel No. 99260( 1 .Report roily Residence Washington This report presents the results of our eologicallgeotechnical assessment for the property located on the east side of Thorndyke Road at a above noted location in Jefferson County, Washington. The purpose of this study was to pro 'de an assessment of the property and steep slope area in order to meet the requirements of Je rson County and to provide design recommendations for placement and construction of the new residence. We understand that you initially intend to build a small, two story house on the upper,portion of the lower area of the site. This residence will eventually become an accessory dwe ling unit (ADU) after the main residence is completed several -years later. The main residen e will likely be a two story house with daylight basement on the relatively flat bench area near t e toe of the relatively gentle slope area about 200 feet or more west of the steep slope overlooks g Hood Canal. See Figure 1, Site and Exploration Plan. Jefferson County has mapped the to r portion of the site, closest to the steep slope area as a landslide hazard area, an erasion haz d area and a seismic hazard area. As such, a geotechnical report addressing these issues is req 'red. This report summarizes our fieldwork and offers recommendations based on our presen understanding of the project. SITE CONDITIONS The subject parcel is a long, narro Thorndyke Road and Hood Canal nee The entire parcel comprises appraxil separated into two azeas, the upper are 4.0 acres and is located closest to T toward the west and has been logged that this area is to remain as forest lan study does not include this portion of ~ rectangular shaped property that is located between the intersection of Thorndyke Road and Seahome Road. ~tely 7.65 acres. For purposes of this study the site is and the lower azea. The upper azea is comprised of about ~rndyke Road. This area slopes very gently downward nd recently replanted with trees. It is our understanding and will not be developed in the foreseeable future. Our property. ary A. Flowers, PLLC. 19532 12~' Avenue NE S oreline, Washington 98155-1106 206-417-7640 1 Schmidt Properly ~i Geotechnical Services Report The lower area of the subject parcel i included in this study. This portion c that gradually transitions into a modes top of the top of the high bank area survey of the site was not available at suitable for this study was available 1 websites and is shown on Figure 1, Sit comprised of about 3.65 acres and is the area of the site 'the property has a very gentle slope in the western part e slope then back to a very gentle slope and finally, at the Tong Hood Canal, becomes very steep. A topographic he time of our study. However, topographic information rough the Jefferson County and Department of Ecology and Exploration Plan. The lower area of the site measures o ~ the order of 900 feet long in the east-west direction by 180 feet wide in the north-south dire Lion. The upper (western) portion of the lower area is relatively flat. Proceeding eastward t e site begins to slope moderately downward toward the east with a gradient between 15 and 2 percent. This moderate slope gradient extends for about 500 feet before leveling off again to a gentle slope with a gradient less that 15 percent. The gentle slope area extends for about 2 0~ feet. The far eastern end of the parcel is high bank above Hood Canal. The high bank is o the order of 50 to 70 feet high and is very steep. The relatively level (western portion) '~ d moderate slope area are heavily vegetated with small diameter deciduous trees and native derstory. A portion of the easternmost gentle slope area (in the area of the proposed septic drai field and future house) has been previously cleazed. The far eastern portion of the site, extending from the top of the high bank about 200 feet to the west, is heavily vegetated with lazge diamete evergreen trees and native understory. No standing or flawing water was ob erved on the lower portion of the site at the time of our field work. No indications of erosio were observed on the site except along the edge of the existing gravel driveway where some tarm water had previously concentrated and caused some minor erosion. This small area of ero ,ion is located several hundred feet to the west of the steep slope azea. Surficial Soil Conditions Surficial soil conditions at the p~ Department of Agriculture (USDA) soils on the western portion of the 1. Kitsap complex (CkD), 15 to 30 1~ Cassolary sandy loam and 40 pert majority of this parcel would be Ca the hazard of water erosion is modes pct site were obtained from applicable United States atural Resource Conservation Service (MRCS). Surficial er part of the site are mapped by the NRCS as Casollary- ent slopes. This unit is made up of roughly 60 percent t Kitsap silt loam. Our explorations indicated that the 1ary sandy loam. For this soil unit runoff is medium and The lower, eastern portion of the site is mapped as Kitsap silt loam (KtE) on 30 to 50 percent slopes. Based on the topography of ~ e site we believe the mapping should be Kitsap silt loam on 0 to 15 percent slopes since the a rage slope gradient on the lower portion of the site is 13 _. _. m 19532 12'~ Avenue NE A. Flowers, PLLC. ;, Washington 98155-1106 2 Schmidt Property Geotechnical Services Report percent. For this soil on 0 to 15 erosion is slight to moderate. Subsurface Soil and Ground Water In order to more thoroughly chazacteri~ on the properly a total of twelve s excavated on the site on May 14, throughout the eastern area of the site approximately located on the Site an attached in Appendix A of this report. follows below. slopes runoff is slow to medium and the hazard of water the shallow subsurface soil and ground water conditions bsurface exploration pits, EP-1 through EP-12, were D07. The exploration pits were excavated randomly n order to ascertain conditions in all areas. The pits are Exploration Plan, attached. The logs of the pits are A general description of our findings and interpretations Exploration pits EP-1 through EP-8 ~~ere excavated on the lower portion of the eastern part of the site. Pits EP-1, EP-2, EP-3, EP-6, EP-7 and EP-8 were excavated in the cleared area where the main residence is planned to be b 'it. Pits EP-4 and EP-5 were excavated in an azea that is still undisturbed forest and where sto water will likely be discharged on the site. Pits EP-9, EP-10, EP-11 and EP-12 were excavat d on the upper portion of the eastern part of the site in the general location where an additional d erring unit will be located. This area has been logged in the past and is currently heavily vegeta ed with small diameter deciduous trees. Glacially consolidated sediments wer observed in all of the explorations excavated on the site except for EP-3 and EP-8 which did of extend to the glacially consolidated sediments. Forest duff and organic topsoil was encounte ~ ed throughout the site and ranged in thickness from about 8 to 24 inches. The topsoil was g erally moist, dark brown silty sand to sandy silt with organics. On the upper portion of the site, in tl (see Site and Exploration Plan) dense, hard, moist, gray, very fine, sandy sir age advanced outwash deposits. The in front of the advancing Vashon age by several thousands of feet of glacial lri exploration pits EP-1, EP-2, EP-3 slope area below the existing drivewa brown to dark brown, sandy silt to overlying dense, moist, light brown t This sediment is likely the upper pc These materials are comprised of inter the last glacial advance in this area. non-glacial periods. These sedirner azea of exploration pits EP-9, EP-10, EP-11 and EP-12, oist, gray very fine sand with silt was observed overlying This material is likely the lower portion of the Vashon materials were deposited in low energy meltwater lakes e sheet and were subsequently overrun and consolidated EP-6, EP-7 and EP-8, located on the moderate to gentle 2.0 to 4.2 feet of loose to medium dense, moist, reddish ilty sand was encountered. This material was observed gray, silty sand with gravel to sand with silt and gravel. rtion of the underlying pre-Vashon stratified sediments. Bedded silts, sands and gravels that were deposited prior to They oftentimes mark the transition between glacial and s have also been overrun and consolidated by several ary A. Flowers, PLLC. 19532 12"' Avenue NE S oreline, Washington 98155-1106 Schmidt Property Wi Geotechnical Services Report thousands of feet of glacial ice. The upper several feet have been loosened by the effects of weathering. Exploration pits EP-4 and EF-5 were ~ xcavated on the gentle slope area between the toe of the moderate slope area and the top of the very steep slope at the eastern edge of the property. The purpose of these pits was to determi a the soil and ground water conditions in the area of planned storm water discharge. Bene th the forest duff/organic topsoil layer 2.5 to 3.2 feet of loose, moist, brown to reddish bro ,silty, medium sand was observed. The sand showed evidence of mottling below a depth o 1.5 feet. Beneath the sand sediments dense, moist, gray, sandy gravel with silt and some silty s d interbeds was observed. This material is likely a part of the pre-Vashon stratified sediments described above. This material has been consolidated by overriding glacial ice. The upper surfa a has been loosened by the effects of weathering. The eastern edge of the property ends to the western edge of the Hood Can comprised of dense to very dense, gr silty sand, sand and gravel. This ma time undercutting of the base of the s face materials results in shallow 1< sediments is confined to the outer 1 depending upon ground water conditic Mappings i a 50 to 70 foot high bank that drops precipitously down . The exposed sediment on the face of the high bank is silty sand with gravel and contains various interbeds of rial is mapped aspre-Vashon stratified sediments. Over pe by wave action and weathering of the very steep slope dsliding. Generally landsliding in these consolidated 3 feet of soil although deep seated landslides can occur s in the area. According to the Geology Map of E tern Jefferson County, revised February 21, 1995, and presented on the Jefferson County we site, the area of the subject property is mapped as Vashon age lodgement till (Vlt} overlying V on age advance outwash sediments (Vao) overlying pre- Vashon stratified sediments (Py). Our findings are in general agreement with the published map of the area. Hydrology Ground water was only encountered i' two of the twelve exploration pits excavated on the site for this study. Ground water was ob ' rued in EP-3 at a depth of 4.3 feet below existing grade and in EP-4 at a depth of 5.3 feet Belo existing grade. No standing or flowing water was observed an the subject site at the time of our field exploration. A small stream of Ovate was observed on the adjacent property to the south. The water was flowing in a small channel ear the property line. Before the water reached the steep slope face it was collected into a tightl ne drain pipe and discharged at the toe of the steep slope. 19532 12"' Avenue NE A. Flowers, PLLC. ;, Washington 98155-1106 4 Schmidt Property W. Geotechnical Services Report We did not observe any direct indicati s of significant ground water flow or springs on adjacent properties within 1000 feet of the subj ct site. We found no indications of nearby springs in the literature. Due to private property res' aints to each side of the subject site we were unable to directly observe the surface water conditions on these properties. CONCLUSIONS AND On the basis of our field investigation potential rotational type of landslide fa retreat affects all steep slopes to sore surficial soils. Due to the very dense the core of the hillside the slope retre average. Some years will see larger m. Based on the proposed location of the steep bank, with no development or decrease slope stability on adjacent pr under normal geologic conditions. Landslide Hazards .TIONS is our opinion that the property is grossly stable from a ire. However, steep slopes are naturally active and bluff extent due to soil weathering and saturation of loose, ~ture of the over-consolidated glacial deposits that form rate is very low, typically measured in inches per year wasting and other years there will be none. .d residences more than 200 feet from the top of the ian of the steep slope area, the proposal will not sand the newly created building sites will be stable Based an our geological reconnaissan ~ e and literature search, it is our opinion that the existing steep slope area is currently stable for urge rotational type of landslides. This is indicated by the following - no major seepage of gro ~ d water was observed on the steep slope, the core of the slope is comprised of dense to very erase, glacially consolidated sediments and there are no current indications of slope movement n the site. Even though the steep slope area belo the proposed project area is generally stable at this time, it is mapped by Jefferson County as a 1 dslide hazard zone. According to the critical areas maps provided by Jefferson County, above pproximate elevation 85 feet the site is mapped as having a slight risk of slope movement. Belo 85 feet the site is mapped as having a high risk of slope movement. We also reviewed the Coastal Zone A' las for the subject area. According to the Atlas the upper portion of the site is mapped as a zon ' of Intermediate Stability and the lower power of the site, near the very steep high bank area, is apped as Unstable. Several areas of recent landslides are shown on the Coastal Zone Atlas map Due to the scale we cannot be certain whether or not any of the mapped areas are located on or jacent to the subject property. A review of the Jefferson County r. Slides - 1999, Overlay of the Criti Revised February 21, 1995, 1999 S 19532 12~' Avenue NE entitled "Taxpayer Parcels Identified as Having New Areas Landslide Hazards, Eastern Jefferson County", s Added March 18, 1999, indi~.ate~.that_there were _6 ,, y A. Flowers, PLLC. ~ ~ _ ____ ine, Washington 98155-1106 206-417-7640 5 Schmidt Property parcels involved in one or mare slides occurred on parcels located According to Jefferson County Code, Use Districts, 18.15.165 Environment Areas, the standard setback from the The two proposed residences will be the steep slope and more than 200 fe such, it is our opinion that the propose site or adjacent properties and the ~ geologic conditions. Erosion Hazards Geotechraical Services Report [ides between 1995 and March 18, 1999. This slide or than 1000 feet to the south of the subject site. itle 18 Unified Development Code, Chapter 18.15 Land y Sensitive Areas, Article VI-G, Geologically Hazardous p, toe and all edges of landslide hazard areas is 30 feet, gated nearly 300 feet or more from more from the top of beyond the edge of the high landslide hazard zone. As development will not decrease the stability of the subject wly created building sites will be stable under normal The steep slope area and the area of site extending upward to approximate elevation 100 are mapped as an erosion hazard area. NRCS soil classification is KtE, Kitsap silt loam, 30 to 50 percent slopes. As detailed abov in the Surftcial Soil Conditions section, based on the topography of the site we believe the ~' mapping should be Kitsap silt loam on 0 to 15 percent slopes since the average slope gradient on the lower portion of the site is 13 percent. For this soil on 0 to 15 percent slopes runoff is sl to medium and the hazard of water erosion is slight to moderate. In addition, no developmen is planned within this area. The areas where the future homes wil from the mapped erosion hazard area. CkD (Casollary-Kitsap complex, 15 made up of roughly 60 percent Cas: explorations indicated that the majori soil unit runoff is medium and the haz Based on the above information, it i normal best management practices recommended for planned developmex soon as possible, mulching areas that of 2 inches of mulch, covering soil st from the steep slope area and constrw of the street from trucks entering and l~ Seismic Hazards The steep slope area and area up to < hazard area. Since the residence will the steep slope and more than 200 fee 19532 12a' Avenue NE be built are located on 15 to 30 percent slopes well away The NRCS soil classifications in these areas are KtE and 0 30 percent slopes. The Cassolary-Kitsap complex is Mary sandy loam and 40 percent Kitsap silt loam. Our ~ of this parcel would be Cassolary sandy loam. For this rd of water erosion is moderate. our opinion that no special erosion mitigation, beyond for construction as per Jefferson County Code is areas. This would include re-vegetating stripped areas as ill not be worked for more than 7 days with a minimum ;kpiles with plastic, channeling storm water runoff away ing a suitable construction entrance to keep sediment off wing the site, if needed. :imate elevation 85 feet are also mapped as a seismic an effeetlve setback of pearl 300 feet from the r --- _....._ i the edge of the hazard area, and;the co#~ of ~ top of e slope nary A. Flowers, PLLC. oreline, Washington 9$155-1106 y 6 .:k~ ~ ~~-a~~-rr~t~~, ;;s~' Schmidt Property W Geotechnical Services Report is comprised of dense to very dense, gl cially consolidated sediments with low risk of large scale rotational failure, the risk to the home from seismically induced slope movement is low and no further mitigation is required. The potential risk from liquefaction induced settlement is negligible. To the best of our knowl dge there are no fault zones located on, adjacent to or nearby to the subject site. Based on the encountered stratigraphy,'' structural design of the project should be consistent with 2003 International Building Code (IB )guidelines. In accordance with Table 1615.1.1 of the 2003 IBC, the subject site would be cl sified as Site Class C. Septic System Placement The location of the proposed septic ain field for the planned residences is shown on the attached Site and Exploration Plan, a site plan is based upon the septic design prepared by Nathan Cleaver Septic Designs. li The planned drain field location is n closest location. The area was previo and more recently cleazed of weeds a location and the top of the steep bank evergreen trees and native understory. the stability of the area with regard to of less than 15 percent slope with mu control practices as described above v geotechnical and erosion control star during both the dry and the wet weathc Geotechnical Recommendations The planned building sites are underl excellent support for the new resident bearing wall footings that extend a m undisturbed or recompacted native sc loosened by the effects of weathering it will be necessary to recompact the placing footing concrete. The footing the entire area recompacted. The foot should be placed atop any loose or yie suitable structural fill. An allowable soil bearing value of including both dead and live loads. ly 200 feet from the top of the steep bank area at its y cleared through permitted logging activities years ago grass that had overgrown the area. Between the septic >ng Hood Canal the area is heavily vegetated with large such, installation of the facility will have no impact on ldslide activity. The area of the drain field is in an area of the area less than 10 percent slope. Normal erosion be suitable for development of the drain field. From a pint, construction of the drain field will be acceptable seasons. by glacially consolidated sediments that will provide As such, the structures can be supported on continuous lum depth of 18 inches below final grade and bear on Since the upper several feet of the soils have been /or have been disturbed by past land clearing activities, ring soils to a dense and unyielding condition prior to ich should be excavated a minimum of 3 feet wide and should then be centered within the trench. No footings lg soils or atop any fill materials that are not verified as X00 psf may be used in the design of the foundatlons,__ _.~ increase of one-third may be used foxshdrl-term v~indmor i, _. - -- ary A. Flowers, PLLC. 19532 12a' Avenue NE S oreline, Washington 98155-1106 ~ ~ {2062417-7640 7 _ ,. ,_ _:. _. Schmidt Property seismic loading. Settlement of foc less than '/2 inch of differential se foundations placed on disturbed or Steps in the foundation grade are acc adjacent to the step. A 1 H:1 V load not daylight on a cut slope or into no All foundation excavations should be i placement, to verify that the design 1 construction conforms to the recommet Lateral loads can be resisted by frict by passive earth pressure acting on i use of 250 pcf for passive pressure three feet of the foundations must be given passive resistance. 'The above 1.5. Retaining Walls Retaining walls that are less than 10 active equivalent fluid pressure of 35 ~ to rotate, it should be designed for backfill. Lateral loads can be resiste soils, and/or by passive earth presses allowable passive earth pressure of 2_` fluid unit weight, and a coefficient of and include a factor of safety of at lei structures, or heavy equipment must b Geotechnical Services Report placed as detailed herein should be less than 1 inch with ant between comparably loaded foundations. However, npacted soil may result in increased settlement. ale provided that none of the foundations are set to bear extending down from the edge of the foundation must tctural fill. 1 by a representative of this firm, prior to concrete capacity of the soils has been attained and that contained in this report. 1 between the foundation and the supporting soils, and/or buried portions of the foundations. We recommend the i a coefficient of sliding friction of 0.3. Backfill within mpacted to a firm and unyielding condition to achieve the hies are allowable and include a factor of safety of at least feet tall and are free to rotate should be designed for an pcf with level backfill. If the wall will be fixed and unable ~ at rest equivalent fluid pressure of 55 pcf with level d by friction between the foundation and the supporting e acting on the buried portions of the foundations. An 0 pcf (pounds per cubic foot), expressed as an equivalent friction of 0.30 may be used. These values are allowable st 1.5. Additional surcharges such as traffic, slope, other added to these design values by the structural engineer. Retaining walls taller than 3 feet must be lined with a minimum of 12 inches of washed rock to within 1 foot of fmish grade or with ~' engineered drain mat such as Inca Drain, Mira Drain or Delta Drain. The drainage layer muste into the footing drain for the wall footing. Ali retaining walls should be backfil d with soil compacted at least minimally to reduce the potential for settlement. In areas wher concrete walkways, driveways, stairs, patio slabs, etc, are planned, the soil should be placed d compacted in lifts to a firm and unyielding condition. Care should be taken to not overcom act the soil as it will add additional pressure against the wall. ary A. Flowers, PLLC. 19532 12~' Avenue NE S reline, Washington 98155-1106 g . _. S E ~o~l~a~ao - _,. _---, Schmidt Property Wi Floor Support Recommendations Slab-on-grade floors should be set structural fill in a firm, unyielding c~ washed pea gravel or clean, coarse g polyethylene plastic vapor barrier sl intrusion is a concern. If the vapor b~ it should be replaced or an additional be wrapped and taped. Drainage Considerations All storm water runoff from impervioi storm water drainage system.. For thi "lower impact development (LID)" ra systems developed atop undisturbed s~ house and septic drain field area wi vicinity of our exploration pits EP-4 as within yard areas. In this manner concentrated water will be discharged Geotechnical Services Report bear on undisturbed or recompacted native soils or Lion. A capillary break layer consisting of 4 inches of ~d, granular soils and a heavy duty (minimum 10 mil), d be provided under any floor slabs where moisture r becomes compromised in any way during construction ~r added. Penetrations through the vapor barrier should surfaces should be collected and piped into an approved site we recommend that the storm water be disposed via 1 gardens and shallow swale techniques or level spreader .ls. These facilities would generally be located below the lin the undeveloped and undisturbed native area in the 3 EP-5. They could also be developed closer to the house infiltration will take place over a large area and no rithin at least 100 feet or more of the steep slope area. Alternatively, the storm water could b ~ collected and tightlined to the beach. area at the bottom of the high bank. Discharge would be i o an engineered energy dissipater to reduce the potential far erosion. Pipe used for this type of system would be butt welded, HDPE (high density polyethylene) that is securely anchore ! at the top and bottom. The size of the pipe and design of the energy dissipater would be selecte by the project civil engineer. All perimeter footing walls should be rovided with a drain at the footing level. Drains should consist of rigid, perforated, PVC pipe urrounded by washed rock. The level of the perforations in the pipe should be set approximat ly at the bottom of the footing and the drains should be constructed with sufficient gradient to I allow gravity discharge away from the buildings. Footing drains that will have more than 10 fe~t of backfill should be constructed of ASTM D:3034 or better sewer grade pipe to minimize tential for collapse. Roof and surface runoff should not discharge into the footing drain syste ,but should be handled by a separate, rigid, tightline drain that discharges into an approved sto water conveyance system. In planning, exterior grades adjacent to walls should be sloped downward away from the structure to achieve surface drainage. Drainage from the long gravel drivev occurring swales along the path. No especially once the driveway begins it' 19532 12`~ Avenue NE ry should be directed off of the driveway into naturally reas of concentrated water discharge should be allowed, descent down to the lower portion of the property. __._ __ A. Flowers, PLLC. ~, Washington 98155-1106 YI16~17~640 9 Schmidt Property Je, ferson County, Washington SUMIVIARY Geotechnical Services Report Based on our site reconnaissance and ubsurface explorations the site appears to be suitable for the proposed development provided the recommendations presented herein are properly implemented. Construction monitoring and consultat on services should be provided to verify that subsurface conditions are similar to those descri din our report. Should conditions be revealed during construction that differs from the ~ ticipated subsurface profile, we will evaluate Chase conditions and provide alternative reco' endations where appropriate. Our findings and recommendations l generally accepted principles of engin the Puget Sound area at the time this express or implied. Thank you for the opportunity to be regarding this matter, please do not h Sincerely, Attachments: Figure 1, Site and Expl Appendix A, Explorati ;d in this report were prepared in accordance with geology and geotechnical engineering as practiced in was submitted. We make no other warranty, either 'service on this project. Should you have any questions fate to contact our office. ~tion Plan Pit Logs 19532 12`" Avenue NB Gary A. Flowers, P.G., P.E.G. Principal Engineering Geologist 4 1~ ~ ~~,o i ~ -. ~ ~ r a W~~ ._~ '~ a 0 __..~.- ~. a~ " _ e-~= W ~ :~ O v = -- --o , m a W ~ as __ -_' ~Y ~ a ~~ a W ,z, ~---150'' E ~ u , o w _ - !-~'~ _~ ~ O ~ 2 k ~ O Z O H Q Q __ ~ 0 J ~ _ _ a O w ~ U O a ~ J ~ O w O a sF / ~_~~/ /~' ~--- 'I 0 r d L', Q1 d W ~~ N CD r O M Q ~ ~ ~ ~ _ ~ O z.~ o ~ ~ Z 0 z -5 O LL Z O Z C9 a cQ 0~~3} W 1- ~a Y '"' O am Z o''.~~N o w W==~ ~~~~ a ~W W Z F- W ~ J_ ~~y V g N N Q g U Z .~ vi 2 c ~ O ~ .~ O ~ a V ~ F- o a w C (n o ~ w u`~ w J ~ U ,i W ~~~ v.:~ _.:' 40~ r Ti __ -.~ Schmidt Property Geotechnicad Services Report Jefferson County, Washington APPENDIX A EXPLORATION LOGS EP-1 0.0' -1.4' forest duff and organic t psoil (moist, dark brown, silty SAND with organics) 1.4' - 4.6' loose, moist, dark bro ,silty SAND 4.6' - 4.9' dense, moist, gray, silty AND with gravel BOH @ 49' No caving No ground water seepage EP-2 '~ 0.0' -1.0' forest duff/organic tops ~'il (moist, dark brown, silty SAND with organics} 1.0' - 3.6' loose, moist, dark bra ' ,silty SAND 3.6' - 4.8' dense, moist, gray, silty SAND with gravel BOH @ 4.8' No cavin~. Na ground water seepage EP-3 0.0' - 2.0' forest duff/organic tops it (moist, black, organic silt) 2.0' - 5.7' loose becoming medi ,dense, moist to wet, brown, silty SAND BOH @ 5.7' Na cavin~. Ground water seepage at 4.3' EP-4 0.0' - 0.7' forest duff/organic tops I it (moist, dark brown, silty SAND with organics) 0.7' - 3.2' loose, moist, brown o reddish brown, silty, medium SAND -becomes moderately mottled bel w 18" 3.2' - 7.5' dense, moist, gray, sand GRAVEL with silt, some silty sand interbeds BOH @ 7.5' No cavin~. Ground water seepage at 5.3' EP-5 0.0' - 0.8' forest duff/organic tops ~ it (moist, dark brown, silty SAND with organics) 0.8' - 4.0' loose, moist, brown o reddish brown, silty, medium SAND -becomes moderately mottled bel w 18" 4.0' - 5.5' dense, moist, gray, san GRAVEL with silt, some silty sand interbeds BOH @ 7.5' No Gavin . Na ground water ~ '~m._.__ _ ___ ____.. A, ~, ary A. Flowers, PLLC. $ ~ P ~ ~ ~ / .,: 19532 12t° Avenue NE Sh reline, Washington 98155-1106 206-417-7640 `d i Schmidt Property Jefferson County. W EP-6 0.0' - 2.0' 2.0' - 4.0' 4.0' - 5.8' EP-7 0.0' - 1.0' 1.0' - 2.7' 2.7' - 5.0' EP-8 0.0' - 1.6' 1.6' - 5.8' EP-9 0.0' - 1.6' 1.6' - 5.5' EP-10 0.0' - 1.0' 1.0' - 6.0' Geotechnical Services Report loose, moist, dark bro silty SAND with organics medium dense, moist, re dish brown, sandy SILT with gravel dense, moist, light bro to gray, silty SAND with gravel to SAND with silt and gravel ~!, BOH @ 5.8' No caving No ground water seepage forest dufflorganic tol medium. dense, moist, dense, moist, light bra gravel BOH @ 5.0' No (moist, dark brown, silty SAND with organics) fish brown, sandy SILT with gravel to gray, silty SAND with gravel to SAND with silt and No ground water seepage forest duff/organic tops it (moist, dark brown, silty SAND with organics) medium dense, moist to very moist with depth, light brown to gray with mottling, sandy SILT to silty S D (below 4.2') BOH @ 5.8' No cavin~ No ground water seepage forest duff/organic tops it (moist, dark brown, silty SAND with organics) dense, moist to very m 'st with depth, gray, becoming brown with mottling below 2.3', very fine SAND th silt BOH @ 5,5' No Gavin No ground water seepage forest duff/organic tops Il (moist, dark brawn, silty SAND with organics) dense, moist, gray, very) fine SAND with silt to silty, very fine SAND BOH @ 6.0' No cavin~ No ground water seepage 19532 12~' Avenue NE A. Flowers, PLLC. ,Washington 98155-1106 ~_ _ ;x SEP 2 7 2001 _ ..,u-_.___. 206<417?~~40 ~;, Schmidt Property Geotechnical Services Report Jefferson Caunty, Washington EP-11 0.0' -1.4' forest duff/organic tops it (moist, dark brown, sandy SILT with organics) 1.4' - 6.0' hard, moist, gray with ttling below 4', very fine sandy SILT BOH @ 6.0' No caving'I No ground water seepage EP-i2 0.0' -1.4' forest duff/organic tops it (moist, dark brown, silty SAND with organics) 1.0' - 5.0' dense, moist, gray with ottling below 4', very fine sandy SILT BOH @ 5.0' No caving, No ground water seepage ary A. Flowers, PLLC. 19532 12~' Avenue NE Sh reline, Washington 98155-1106