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11.15.2012-Earth_Solutions-Geotech_Assessment.pdfNovember 15, 2012 ES-2479 Ardsley Homes, LLC 16108 Ash Way, Suite 201 Lynnwood, Washington 98087 Attention: Mr. Lyle Landrie Subject: Geotechnical Assessment Letter Proposed Hill Lake Property 24223 & 24227 — 76t" Avenue West Edmonds, Washington Dear Mr. Landrie: Earth ( Solutions NW«C Earth Solutions NW LLC • Geotechnical Engineering • Construction Monitoring • Environmental Sciences In accordance with your request, Earth Solutions NW, LLC (ESNW) has prepared this letter and geotechnical assessment for the subject property. The approximate location of the property is illustrated on the attached Vicinity Map (Plate 1). Based on the results of this geotechnical assessment, development of the site as proposed is feasible from a geotechnical standpoint. The site is currently partially developed with three one-story single-family residential buildings and several detached garage/shed structures located at the western end of the property. The majority of the property is undeveloped with lightly forested landscaping consisting of grass, ferns, and rhododendron bushes. We understand that the subject property will be subdivided and redeveloped with approximately seven residential lots. The development will also incorporate a stormwater tract and related detention vault facility. Based on field observations, overall topography is gently sloping to the east toward Lake Ballinger with an isolated shallow depression located at the southwest corner of the property along the south property line. Geotechnical Assessment ESNW was onsite August 2, 2012 to conduct a subsurface field exploration by observing soil conditions and collecting soil samples at a series of test pits excavated throughout the proposed project. An excavator was utilized to excavate to a maximum exploration depth of 12 feet below current grades. The approximate locations of the test pit excavations are illustrated the attached Test Pit Location Plan (Plate 2). The geologic map of the Edmonds East Quadrangle (1983) identifies recessional outwash (Qvr) deposits at the site and surrounding area. The geologic map of the Edmonds East Quadrangle (1983) also identifies the contact between glacial till (Qvt) and recessional outwash (Qvr) deposits to be immediately west of the property along 76t" Avenue West. 1805 - 136th Place N.E., Suite 201 0 Bellevue, WA 98005 9 (425) 449-4704 • FAX (425) 449-4711 Ardsley Homes, LLC ES-2479 November 15, 2012 Page 2 Evidence of existing fill was encountered at test -location TP-7. Existing fill soils were observed at this location to a depth of approximately 1.5 feet below existing grades with organic rich material underlying. Fill soils consisted primarily of medium dense, dry to moist silty sand soils. Evidence of extensive, wide -spread existing fill was not encountered, however, shallow existing fill soils may be encountered near and adjacent to the existing structures, the asphalt access driveways, and at previously filled localized depressions. Sod/Topsoil was encountered at all test sites extending to depths of approximately three to eight inches below existing grades at the majority of the test pit locations. However, a thicker topsoil horizon with peat like organic soil characteristics consisting of fibrous wood fragments was encountered at TP-1 and TP-3 to a depth of 1.5 to 2.5 feet below existing grades. Topsoil was also encountered below the existing fill soils at TP-7 from 1.5 to 3.0 feet below existing grades This topsoil horizon likely represents the native surface elevation prior to placement of existing fill. Topsoil is not suitable for foundation or pavement support, and should not be mixed with soil to be used as structural fill. The topsoil can be considered for use in landscape or non- structural areas, if desired. Underlying the topsoil horizon, loose to medium dense silt with sand and medium dense to very dense silty sand (native till soil), and well graded sand with silt and gravel (native outwash soil) was observed to a maximum excavation depth of 12.0 feet. Please refer to the subsurface exploration soil logs provided as an attachment to this report for a more detailed description of the subsurface conditions. The soil conditions encountered during our fieldwork generally correlate with the geologic map designation with soils consisting of glacial till (Qvt) soils thought the majority of the property, and outwash sand (Qvr) deposits encountered at the eastern most portion of the subject site. Groundwater seepage was encountered at test pit locations TP-1, TP-2, and TP-3. Light groundwater seepage was observed to be encountered at depths between 2.5 and nine (9) feet below existing soil elevations. Seepage rates were observed to decrease approximately 10 minutes following initial exposure. Seepage should be anticipated in deeper site excavations and utility installation depending on the time of the year excavations are made. Groundwater encountered during our field exploration would be characterized as localized perched groundwater seepage, and not a water bearing groundwater table condition, however, based on the close proximity to Lake Ballinger, groundwater table should be anticipated within deeper excavations (approximately 12 or more feet below the existing grade). Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter months. Earth Solutions NW, LLC Ardsley Homes, LLC November 15, 2012 Site Preparation and Earthwork ES-2479 Page 3 With respect to earthwork, the primary considerations at this site are related to grading for new building lots, placement and compaction of fill, suitability of the native soils for use as structural fill, soil bearing capacity, temporary excavations for utility structures, and erosion control measures. The existing residential structures and associated improvements will be removed. Once the existing structures have been removed and temporary erosion control measures have been installed, clearing and grubbing of the property will commence. In -Situ Soils From a geotechnical standpoint, the soils encountered below the upper topsoil and organic rich soil horizons are generally suitable for use as structural fill provided the soils are at or near optimum moisture content during placement (and are free of organic materials). Successful use of the on -site soils will largely be dictated by the moisture content of the soils at the time of placement and compaction. The soils encountered at the test sites were generally in a moist to wet condition at the time of the exploration (August 2012). Due to the relatively high fines content of the onsite soils, an elevated moisture content may result in pumpy surface conditions during site preparation and initial site fill activities. Soils encountered at or near perched seepage elevations during site excavations that are excessively over the optimum moisture content will require moisture conditioning prior to placement and compaction. Highly organic or compressible soils encountered at the upper three to four feet adjacent to TP- 1 and TP-3 at the eastern portion of the property should not be used as structural fills below roadway and building structures. Soils encountered at this location may require additional overexcavation or recompaction within the building and roadway envelope to achieve suitable soil bearing conditions. Organic and compressible soils cut from site excavations may be placed in non-structural and landscape areas if desired. During periods of dry weather, the on -site soils should generally be suitable for use as structural fill, provided the soil moisture content is at or near the optimum level at the time of placement. Successful placement and compaction of the on -site soils during periods of extended precipitation will likely be difficult. If the on -site soils cannot be successfully compacted, the use of an imported soil may be necessary. Imported soil intended for use as structural fill should consist of a well graded granular soil with a maximum aggregate grain size of six inches, and a moisture content that is at or near the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of five percent or less defined as the percent passing the #200 sieve, based on the minus three-quarter inch fraction. Earth Solutions NW, LLC Ardsley Homes, LLC November 15, 2012 Structural Fill ES-2479 Page 4 Structural fill is defined as compacted soil placed in foundation, slab -on -grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are also considered structural fill. Soils placed in structural areas should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 90 percent, based on the maximum dry density as determined by the Modified Proctor Method (ASTM D-1557). In pavement areas, the upper 12 inches of the structural fill should be compacted to a relative compaction of at least 95 percent. Utility trench backfill should be compacted to the specifications of the controlling jurisdiction, where applicable. Temporary Erosion Control Temporary erosion control measures should include, at a minimum, silt fencing placed along the downslope perimeter of the construction envelope. The temporary construction entrance should consist of at least six inches of quarry spalls to help minimize off -site soil tracking and to help provide a stable temporary road base. The quarry spall blanket should be underlain by a woven geotextile. Excavations and Slopes The Federal Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. Based on the soil conditions encountered during our fieldwork, the native soils encountered in the upper approximately four feet are classified by OSHA/WISHA as Type C. Temporary slopes over four feet in height in Type C soils should be sloped no steeper than 1.5H: 1 V (Horizontal: Vertical). The dense to very dense native soils encountered below about five feet would be classified as Type A by OSHA/WISHA. Temporary slopes over four feet in height in Type A soils should be no steeper than 0.75H: 1V. If the recommended temporary slope inclination cannot be achieved, temporary shoring may be necessary to support the excavations. Where groundwater is encountered, the soil should be treated as Type C. The geotechnical engineer should observe the excavations to confirm soil and groundwater conditions. At the time this report was written, specific finished floor elevations had not been determined. Based on the existing soil elevations and adjacent roadway elevations, we anticipate onsite excavation for the stormwater detention vault and underground utilities will be on the order of 14 feet or less to achieve designed subgrade elevations. If the recommended temporary slope inclination cannot be achieved, temporary shoring may be necessary to support the excavations. Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with vegetation to enhance stability and to minimize erosion. Earth Solutions Nw, LLC Ardsley Homes, LLC ES-2479 November 15, 2012 Page 5 Water should not be allowed to flow over temporary or permanent slopes. During rain events, exposed temporary slopes should be covered with plastic sheeting and runoff should be directed to an approved storm system and away from the slope. The project geotechnical engineer should observe temporary and permanent slopes to confirm the inclination is suitable for the exposed soil conditions, and to provide additional grading recommendations, as necessary. Foundations Based on the expected subsurface conditions, the proposed building structures can be supported on conventional continuous and spread footing foundations bearing on medium dense native soils, or structural fill immediately underlain by competent (medium dense) native soil. Where loose or unsuitable soils are exposed at the foundation subgrade elevation, the soils should be overexcavated and replaced with suitable structural fill. Topsoil and organic rich soils should be removed from foundation areas. Assuming the buildings will be supported as described above, the following parameters can be considered for design of the new foundations: • Allowable Soil Bearing Capacity ■ Passive Resistance ■ Coefficient of Friction • IBC Seismic Site Class ■ Liquefaction Susceptibility 2,500 psf 350 pcf (equivalent fluid) M M Site Class D (table 1613.5.2, 2009 IBC) low A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. Competent soils suitable for support of foundations are anticipated to be encountered at depths of about two to three feet below existing grades. Where existing fill and/or thickened topsoil horizon is encountered (TP-1, TP-3, and TP-7), depth to bearing may be locally deeper. Where loose or unsuitable soils are encountered at the foundation subgrade elevation, the soil should be recompacted in place or overexcavated to competent (medium dense) soil conditions and replaced with suitable structural fill. Earth Solutions NW, LLC Ardsley Homes, LLC November 15, 2012 Vault Foundation ES-2479 Page 6 Competent native soils suitable for support of vault foundations were generally encountered at depths of roughly five to seven feet below existing grade (dense to very dense unweathered till). Perched groundwater seepage was encountered throughout the eastern portion of the site at depths of 2.5 to nine (9) feet, and was light to moderate at some locations. In this respect, sumps and related construction dewatering techniques may be required during excavation and construction of the vault. Due to the presence of perched groundwater seepage, a provision for hydrostatic pressures should be incorporated into the design where use of a footing drain at the base of the vault is not practicable. In this respect, assuming the vault excavation will be advanced into the unweathered till, the following geotechnical parameters can be used: • Allowable Soil Bearing Capacity 5,000 psf (unweathered till) • Active Earth Pressure (Yielding Wall) 35 pcf • At -Rest Earth Pressure (Restrained Wall) 50 pcf • Hydrostatic Pressure At base — Applicable If No Ftg. Drain (per Geotech.) • Hydrostatic Uplift — Applicable If No Ftg. Drain (per Geotech.) • Soil Unit Weight 125 pcf • Active Earth Pressure Coefficient (Ka) 0.28 • At -Rest Earth Pressure Coefficient (Ko) 0.40 Where applicable, a surcharge from adjacent traffic loading or structures should be added to the calculated earth pressures. ESNW can provide surcharge loading values, as necessary. Additionally, the geotechnical engineer should observe the vault excavation to confirm soil and groundwater conditions. As necessary, supplement geotechnical recommendations for foundation support (or drainage) will be provided. Additionally, recommendation for hydrostatic pressures and related earth pressures will be provided as needed during the vault design process. Utility Trench Backfill In our opinion, the soils observed at the test sites are generally suitable for support of utilities. Organic or highly compressible soils encountered in the trench excavations should not be used for supporting utilities. In general, the on -site soils observed at the test sites should be suitable for use as structural backfill in the utility trench excavations, provided the soil is at or near the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soils may be necessary at some locations prior to use as structural fill. The presence of groundwater seepage should be expected in site excavations, such as the deeper utility trench excavations. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable specifications of the city or county jurisdictions. Earth Solutions NW, LLC Ardsley Homes, LLC November 15, 2012 Drainage ES-2479 Page 7 Groundwater seepage was encountered at the time of our fieldwork (August, 2012). The presence of isolated zones of perched seepage should be anticipated during deeper site and utility excavations. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve interceptor trenches and sumps, as necessary. In our opinion, the proposed residential structures and detention vault should incorporate footing drains around the outside perimeter of the foundations. Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications detailed in the "Structural Fill section of this report. It is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas containing unsuitable or yielding subgrade conditions will require remedial measures such as overexcavation and thicker crushed rock or structural fill sections prior to pavement. For relatively lightly loaded (low frequency) pavements subjected to automobiles and occasional truck traffic, we recommend the following pavement section: • Two inches of asphalt concrete (AC) placed over four inches of crushed rock base (CRB), or; • Two inches of AC placed over three inches of asphalt treated base (ATB). Heavier truck -traffic areas and main access drives generally require thicker pavement sections depending on site usage, pavement life expectancy, and site traffic. ESNW can provide appropriate pavement section design recommendations for heavier (high frequency) areas, as necessary. Additionally, the City of Edmonds Road Standards (or applicable jurisdiction) may supersede the recommendations provided in this report. LIMITATIONS The recommendations and conclusions provided in this geotechnical assessment are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test sites may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical assessment if variations are encountered. Earth Solutions NW, LLC Ardsley Homes, LLC November 15, 2012 Additional Services ES-2479 Page 8 ESNW should have an opportunity to review the final design with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. We trust this geotechnical assessment meets your current needs. If you have any questions regarding the content of this document or require additional information, please call. Sincerely, EARTH SOLUTIONS NW, LLC B. Tyler Scalise Staff Geologist Attachments: Plate 1 —Vicinity Map Plate 2 — Test Pit Location Plan Test Pit Logs and Lab Data oN° A. �o Q � �8 3608 �4 Raymond A. Coglas, P.E. Principal Earth Solutions NW, LLC NORTH Reference: Snohomish County, Washington Map475 ByThe Thomas Guide Rand McNally 32ndEditipn NOTE: This plate may contain areas ofcolor. ESNWcannot be responsible for any subsequent misinterpretation ofthe information resulting from black & white reproductions ofthis plate. Checked BTS Date Aug. 2012 Plate 1 6--` w I I I I \ V \ Z I I \ Q I I I I I I \ Existin I — —t I g � Existing TP-21 - - - - - - - i TP-5 I TP-31 A ITP-6 \1/\ TP-4 I TP-11 - �L - TP-7 1 Existing —■—� —■— Existing House t Garage � Existing — Shed I I LEGEND TP-1-1l—Approximate Location of ESNW Test Pit, Proj. No. ES-2479, Aug. 2012 Subject Site Existing Building �y 71 Approximate Wetland Area (Delineated By Others) NOTE: The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the approximate test locations relative to the approximate locations of existing and / or proposed site features. The information illustrated is largely based on data provided by the client at the time of our study. ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. NORTH 0 50 100 200 1 "=100' �I � Scale in Feet Test Pit Location Plan Hill Lake Ballinger Plat Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drwn. GLS Date 08/16/2012 Proj. No. 2479 responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked BTS Date Aug. 2012 Plate 2 Earth Solutions NWLLC SOIL CLASSIFICATION CHART MAJOR DIVISIONS SYMBOLS TYPICAL DESCRIPTIONS GRAPH I LETTER GRAVEL AND CLEAN GRAVELS ��•�� �' GW WELL -GRADED GRAVELS, GRAVEL - F NE) MIXTURES, LITTLE OR NO ° Qo oQo 0 0�0 0 O Q °O GP POORLY -GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES GRAVELLY SOILS (LITTLE OR NO FINES) COARSE GRAINED SOILS MORE THAN 50% OF COARSE GRAVELS WITH FINES ° 00 ° `° ° D GM SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES FRACTION GC CLAYEY GRAVELS, GRAVEL - SAND CLAY MIXTURES RETAINED ON NO. 4 SIEVE (APPRECIABLE AMOUNT OF FINES) SAND AND CLEAN SANDS SW WELL-GDED SANDS, RAVELLY SANDS, LITTLE OR NO FINES MORE THAN 50% OF MATERIAL IS SP POORLY -GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES LARGER THAN NO. 200 SIEVE SIZE SANDY SOILS (LITTLE OR NO FINES) SANDS WITH SM SILTY SANDS, SAND - SILT MIXTURES MORE THAN 50%FINES OF COARSE FRACTION SC CLAYEY SANDS, SAND - CLAY MIXTURES PASSING ON NO. 4 SIEVE (APPRECIABLE AMOUNT OF FINES) INORGANIC SILTS AND VERY FINE ML SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY FINE GRAINED SOILS SILTS LIQUID LIMIT AND LESS THAN 50 CLAYS CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY MORE THAN 50% OF MATERIAL IS SMALLER THAN NO.200 SIEVE MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS SIZE SILTS LIQUID LIMIT AND CLAYS GREATER THAN 50 CH INORGANIC CLAYS OF HIGH PLASTICITY MAMA OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS HIGHLY ORGANIC SOILS—'' '"' ' „„ PT HUMUS, SWAMP SOILS WITH HIGH HIGH ORGANIC CONTENTS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. Earth Solutions NW TEST PIT NUMBER TP-1 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 oil Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Ardsley Homes; LLC PROJECT NAME Hill Lake Ballinger Plat PROJECT NUMBER 2479 PROJECT LOCATION Edmond, Washington DATE STARTED 8/2/12 COMPLETED 8/2/12 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavatinq GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION --- LOGGED BY BTS CHECKED BY BTS AT END OF EXCAVATION --- NOTES Depth of Topsoil & Sod 0"- 2": grass AFTER EXCAVATION — w _ HLu N U a a w V 0 p MATERIAL DESCRIPTION w a� <J Q Z C7 0 Brown to black TOPSOIL with "peat like" soil characteristics, loose, wet TPSL L' Brown sandy SILT, loose, moist to wet ML 3.0__ Dark brown poorly graded medium to coarse SAND with silt and gravel, medium dense to dense, moist SP- SM -slight caving 5 5.0 -light seepage Gray silty SAND with gravel, dense, moist to wet -becomes very dense SM 10 10.0 Test pit terminated at 10.0 feet below existing grade. Groundwater seepage encountered at 4.5 feet during excavation i I i i Bottom of test pit at 10.0 feet. Earth Solutions NW 1805 136th Place N.E., Suite 201 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Ardsley Homes, LLC PROJECT NUMBER 2479 DATE STARTED 8/2112 COMPLETED 8/2/12 EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD LOGGED BY BTS CHECKED BY BTS NOTES Depth of Topsoil & Sod 0"- 4": grass w >_ U a w Co U 0_0 wQ" Q z c7 U) ML SP- SM 10 TEST PIT NUMBER TP-2 PAGE 1 OF 1 PROJECT NAME Hill Lake Ballinger Plat PROJECT LOCATION Edmond, Washington GROUND ELEVATION TEST PIT SIZE GROUND WATER LEVELS: AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION — MATERIAL DESCRIPTION Gray SILT with trace gravel, loose to rrediun: dense, moist Becomes blue -gray poorly graded SAND with silt, dense, moist -becomes very dense -light seepage 12.0 Test pit terminated at 12.0 feet below existing grade. Groundwater seepage encountered at 9.0 feet during excavation. Bottom of test pit at 12.0 feet. TEST PIT NUMBER TP-3 Earth Solutions NW 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT _Ardsley Homes. LLC PROJECT NAME Hill Lake Ballinger Plat PROJECT NUMBER 2479 PROJECT LOCATION Edmond,_ Washington DATE STARTED 8/2/12 COMPLETED 8/2/12 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION --- LOGGED BY BTS CHECKED BY BTS AT END OF EXCAVATION NOTES Depth of Topsoil & Sod 6"- 8": grass. AFTER EXCAVATION -- w }W Ui a$ J U a p MATERIAL DESCRIPTION w" �_j Q Z C7 U) 0 — Brown to black TOPSOIL with "peat like" soil characteristics, loose, wet TPSL 25 -light seepage at 2.5' Gray SILT with fibrous wood fragments, loose to medium dense, moist to wet ML 4.0 -increase in fine sand Gray poorly graded SAND with silt, medium dense, moist to wet 5 SP- SM -gravel layer 9.0 Test pit terminated at 9.0 feet below existing grade. Groundwater seepage encountered at 2.5 feet during excavation. Bottom of test pit at 9.0 feet. Earth Solutions NW liq 1805 136th Place N.E., Suite 201 Bellevue, Washington 98005 Telephone: 425-284-3300 TEST PIT NUMBER TP-4 PAGE 1 OF 1 CLIENT Ardsley Homes, LLC PROJECT NAME Hill Lake Ballinger Plat PROJECT NUMBER 2479 PROJECT LOCATION Edmond, Washington DATE STARTED 8/2/12 COMPLETED 8/2/12 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION --- LOGGED BY BTS CHECKED BY BTS AT END OF EXCAVATION --- NOTES Depth of Topsoil & Sod 6"- 8": grass AFTER EXCAVATION --- w }o U a wm U ap wo" a� ¢z U) ML 5 1 1 SM 15 8.0 MATERIAL DESCRIPTION Gray SILT with sand, medium dense, moist Gray silty SAND with gravel, medium dense to dense, moist -decrease in silt content -becomes moist to wet -slight caving Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 8.0 feet. Earth Solutions NW TEST PIT NUMBER TP-5 1 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 No;=Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Ardslev Homes. LLC PROJECT NAME Hill Lake Ballinger Plat PROJECT NUMBER 2479 PROJECT LOCATION Edmond, Washington DATE STARTED 8/2112 COMPLETED 8/2/12 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating_ GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION --- LOGGED BY BTS CHECKED BY BTS AT END OF EXCAVATION --- NOTES Depth of Topsoil & Sod 4"- 6": grass AFTER EXCAVATION -- w H^ � }Lu U a U w w CoL) O MATERIAL DESCRIPTION aj QZ Z5 � U U) 0 Gray SILT, loose, moist ML -becomes medium dense 3.0 Becomes blue -gray silty SAND with gravel, dense, moist 5_ -increase in sand and gravel SM -decrease in fines content -becomes very dense, increase in fines content 8.5 Test pit terminated at 8.5 feet below existing grade. No groundwater encountered during excavation. i i l Bottom of test pit at 8.5 feet. Earth Solutions NW 1805 136th Place N.E., Suite 201 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Ardsley Homes, LLC PROJECT NUMBER 2479 DATE STARTED 8/2112 COMPLETED 8/2/12 EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD LOGGED BY BTS CHECKED BY BTS NOTES Depth of Topsoil & Sod 3"- 4": grass TEST PIT NUMBER TP-6 PAGE 1 OF 1 PROJECT NAME Hill Lake Ballinger Plat PROJECT LOCATION Edmond, Washington GROUND ELEVATION TEST PIT SIZE GROUND WATER LEVELS: AT TIME OF EXCAVATION --- AT END OF EXCAVATION --- AFTER EXCAVATION -- _ aZ w" 0 w W wm a� ¢z 0 U vi U ap �_j Gray SILT with sand, medium dense, moist -becomes dense - ML -increase in clay content -increase in moisture 5 -becomes moist to wet SM MATERIAL DESCRIPTION Gray silty SAND with gravel, very dense, moist Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 8.0 feet. TEST PIT NUMBER TP-7 Earth Solutions NW 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Ardslev Homes, LLC PROJECT NAME Hill Lake Ballinger Plat PROJECT NUMBER 2479 PROJECT LOCATION Edmond Washington DATE STARTED 8/2/12 COMPLETED 8/2/12 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION --- LOGGED BY BTS CHECKED BY BTS AT END OF EXCAVATION --- NOTES Depth of Topsoil & Sod 0"- 4": grass AFTER EXCAVATION -- w a - of U a a p MATERIAL DESCRIPTION wv o-� vi �_j Q Z C9 0 Brown silty SAND, medium dense, dry to moist (Fill) SM 1.5 `— Brown to black TOPSOIL, loose, wet TPSL — 3.0 Gray SILT, loose to medium dense, moist ML 5 5.5 Blue -gray silty SAND with gravel, dense, moist SM -becomes very dense, moist to wet 10 10.0 Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation. _ Bottom of test pit at 10.0 feet.