Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
GEO2011-00071 for FPA2011-00010 - GEO Geological Review - 10/4/2011
(6/12/2008) Michael MacSems-Geotechnical Report Review Checklist 6-08.doc Page 1 (r �C Zc11 - Mason County Review Checklist For a Geotechnical Report Instructions: This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnical Report 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 Report 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 wt Name: 1 IC, C, I km C� C U Permit# FAA zoll - ()CCAU Parcel# ff� 2 q Z) — CCU G 7U0U Date(s)of the Document(s)reviewed: i U A l �� (1) (a)A discu ion of general geologic conditions in the vicinity of the proposed development, OK?Comment: (b) A discussion of specific soil types OK? V Comment: (c) A discussion of ground water c nditions OK?_ Comment: I_ (d) A dis yKsion of the upslope geomorphology OK? t Comment: (e) A dis ssion of the location of upland wa r odies and wetlands ` OK?�Comment: ,�4 Z, (f) A discussion of history of de activity in the activity in the vicinity,as available in the referenced maps and records �� Z ? OK?�Comment: J (2) A site pl which identifies the important development and geologic features. OK? Comment: (3) Locations!nd logs of exploratory holes or probes. OK? Comment: (4) The area of the proposed development,the boundaries of the hazard, and associated buffers and setbacks shall be delineated (top, both sides,and toe)on a geologic map of the site. -� OK?V Comment: Utj j L S'P/ 4 (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile,and which incofporates the details of proposed grade changes. OK? ✓ Comment: (6) A description and results of slope stability analyses performed for both static and seismic loading conditions.Analysis should examine worst case failures.The analysis should include the Simplified Bishop's Method of Circles.The minimum static safety factor is 1.5,the minimum seismic safety factor is 1.1.and the quasi-static analysis coeffients should be a value of 0.15. OK? V Comment: (7) (a)Appryriate restrictions on plaW ntf drainage features OK? Comment: 9 (b) Appropriate restrictions o�enUf septic drain fields ' "AA OK? Y Comment: (c) Appropriate restrictions on placemeA of compacted fills and footings OK? V Comment: (d) Recommended buffers from the land Slide hazard areas shoreline bluffs and the tops of other slopes on the property. Page 1 of 2 Form Effective June 2008 I (6/12/2008) Michael MacSenns - Geotechnical Report Review Checklist 6-08.doc Page 2 OK? I Comment: S (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of othVlopes on the property. (PCOK? Comment: (8) Recommendations for the preparatiorrof a detailed clearing and grading plan which specifically identifies vegetation to be removed,a schedule for vegetation removal and replanting,and the method,of vegetation removal. 1 OK? Comment: reC k 4 V)"T I o (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, II ndslides and harmful construction methods. OK? Comment: (10) An anal ys}s of both on-site and off-site i pacts of the proposed development. OK? i/ Comment: c, 61 (11) Specifications of final development condi ions such as,vegetative management,drainage, erosion control,and buffer widths. OK? <Comment: fj L (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. OK?Ll Comment: (13) A site map drawn to scale showing th property boundaries,scale,north arrow,and the location and naturK of existing and proposed development on the site. OK? Comment: Are the Documents signed and stamped? . Type and#of License: L i CC @cll v 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 Cleo 2411, Mason County Department of Community Development Submittal Checklist For a Geotechnical Report Instructions: This checklist must be submitted with a Geotechnical Report and completed, signed,and stamped by the licensed professional(s)who prepared the Geotechnical Report 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 l4p,aAA m k Parcel# Site Address c b "tip il (1) (a)A discussion of general geologic conditions in the vicinity of the proposed development, Located on page(s) 1V u t", XX X X OC= (b) A discussion of spe �f c soil types Located on page(s) (c) A discussion of grourfd water conditions Located on page(s)_;�) '-t F�XX — (d) A discussion of the upslope geomorphology Located on page(s)-,,) 7,. (e) A discussion of the location of upland waterbodies and wetlands Located on page(s) ( D, (f) A discussion of history of landslide activity in the activity in the vicinity,as available in the referenced maps end records Located on page(s) �__ (2) A site plan which identifies the important cLevelopment and geologic features. Located on Map(s) 1 � a S l4w'�, -a- (3) Locations and logs of exploratory holes or probes. Located on Map(s) F Tic4c�i a ICN�C (4) The area of the proposed development, the boundaries of the hazard, and associated buffers and setbacks shall be delineated(top,both sides,and toe)on a geologic map of the site. Located on Map(s)(--1 q-.J 6 T a F n n C- r. (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile,and which incorporates the d tails of proposed grade changes. Located on Map(s) _. .�ti2QU txfif (6) A description and results of slope stability analyses performed for both static and seismic loading conditions.Analysis should examine worst case failures.The analysis should include the Simplified Bishop's Method of Circles.The minimum static safety factor is 1.5, the minimum seismic safety factor is 1.1. and the quasi-static analysis coeffients should be a value of 0.15. Located on page(s) IS- (7) (a)Appropriate restr"ic logs on placement of drainage features Located on page(s) 14 k (b) Appropriate restricti s on placement of septic drain fields Located on pages) (c) Appropriate restrictio on placement of compacted fills and footings Located on page(s) fir, Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. (d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes on the prope Located on pages) -- (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the p operty. Located on page(s) (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed,a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) j (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion,land lides and harmful construction methods. Located on page(s) (10) An analysis of both on-site a d off-site impacts of the proposed development. Located on page(s) _� ,S h i, (11) Specifications of final development conditions such as,vegetative management,drainage, erosion control, and buffer widths. Located on page(s) _`� . (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) (13) A site map drawn to scale showing the property boundaries,scale,north arrow, and the location and nature of existin and proposed development on the site. Located on Ma s A - 'C? 1'. = ' hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical Report,datedS� (`,AEm t 44:�-'1and entitled F f ,F _c� ►�•y �,o►J 'ui�.J . ��� . _ -C`LVA I,�24 I\,'j kc\,pi meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard Section, is complete and true, that the assessment demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the included geotechnical design recommendations, and that all hazards are mitigated in such a manner as to prevent harm to property and public health and safety. (Signature and Stamp) �{ Iashy 326^ r' STEPHEN P. PALMER Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. DESIGNK September 19, 2011 Hama Hama Company 301 North Webb Road Lilliwaup, WA 98555 Attention: Mr. David Robbins Report of Reclamation Plan Slope Stability Evaluation Hama Hama Gravel Pit Mason County, Washington Geol)esign Project: HamaHama-1-02 INTRODUCTION GeoDesign, Inc. is pleased to submit this geotechnical slope stability report for the proposed development of the Hama Hama Gravel Pit located in Mason County, Washington. The purpose of our report is to fulfill requirements by Mason County Department of Community Development (MCDCD) for the Forest Practices Application (FPA) needed for initial development of the mine. We contacted Mr. Michael MacSims of MCDCD to clarify the requirements for the FPA, which include completion of the Submittal Checklist for a Geotechnical Report. We discussed the scope and content of our July 14, 2009 geotechnical report prepared to support the mine reclamation plan, which met all of the requirements of the geotechnical report checklist. Mr. MacSims agreed that many of the specific items provided in the 2009 report can be used in completing the required checklist for the FPA geotechnical report. He stated that Mason County was concerned with the impacts to slope stability from timber removal prior to mine development and that an evaluation of timber harvest on slope stability is required. In this report we evaluated shallow slope stability using soil properties (thickness, grain texture, depth to groundwater, etc.) derived from the Natural Resources Conservation Service (NRCS) soil mapping for Mason County. We developed a slope gradient map from the light detection and ranging (LiDAR) topographic data available for the mine site. We modeled slope stability using our estimates of soil properties derived from the NRCS mapping and slope gradients obtained from the LiDAR data and also considering the decrease of soil strength after timber removal resulting from loss of root cohesion. The results of this slope evaluation are provided in this FPA report, and we will submit this report and a copy of our 2009 report to meet all of the specific items required in the geotechnical report checklist. Mr. MacSims agreed to this approach so that we reduce the redundancy of information contained in this FPA report. 61M 15575 SW Sequoia Pkwy-Suite 100 1 Portland,OR 97224 1 off 503.968.8787 1 Fax 503.968.3068 A copy of our July 14, 2009 geotechnical report, which was prepared to support the mine reclamation plan for the proposed gravel pit, is included in the Attachment to this report. The 2009 report provides a background regarding site conditions, including slope stability modeling related to mine development and reclamation. This slope modeling did not focus on shallow landslides that may be associated with timber harvest, which would precede soil stripping and mine development. The focus of this report is on the evaluation of timber harvest on shallow soil slope stability. SOIL, SLOPE,AND GROUNDWATER CONDITIONS RELATED TO TIMBER HARVEST We have utilized soil mapping data obtained from NRCS (NRCS, 201 1)' and our observations during our field reconnaissance conducted April 20, 2009 to define soil and groundwater conditions used in the slope stability modeling. A slope gradient map of the site was developed from LiDAR topographic data obtained from the Puget Sound Lidar Consortium and is shown on Figure 1. The approximate extent of the timber harvest proposed to support the first phase of mine development is shown on Figure 1. SOIL AND GROUNDWATER CONDITIONS The steeper slope area of the proposed timber harvest is underlain by Hoodsport gravelly sandy loam (NRCS, 2011). This soil unit ranges from 20 to 40 inches in thickness and is underlain by dense glacial till that comprises the unweathered parent material of the Hoodsport gravelly sandy loam. Groundwater depths in this soil unit are reported to range from 18 to 36 inches. Based on the data provided by NRCS (201 1) and our field observations, we have assumed a soil layer thickness of 3 feet (36 inches) for the Hoodsport gravelly sandy loam in our slope stability modeling. We have also assigned a groundwater depth of 1.5 feet (18 inches) based on the shallowest reported depth to groundwater from the NRCS(201 1) data. These input parameters to our slope stability modeling are summarized in Table 1. In our 2009 report we used back calculation to determine the soil strength parameters for the dense glacial material that underlies the mine site and is the parent material for the surficial soil that supports the forest vegetation. Our back calculation for the dense glacial materials indicated that the internal angle of friction (o) is 39 degrees and that the soil cohesion (c) is 75 pounds per square foot (psf). It can be anticipated that the strength parameters of a soil horizon will be less than those of the parent material. Consequently, we have used typical soil strength values for medium dense, gravelly sand (o equal to 30 degrees and c equal to 40 pso as input parameters to our slope stability modeling as indicated in Table 1. We have used a soil unit weight of 126.5 pounds per cubic foot (pco based on a typical unit weight for gravelly sand (1 10 pcf) having a moisture content of 15 percent. NRCS,2011,Custom soil report for Mason County,Washington-Hama Hama Gravel Pit:Soil Survey Staff,Natural Resources Conservation Service,United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nres.usda.gov/accessed[09/05/2011]. MDESIGN`' 2 HamaHama-1-02:09191 1 I TREE SURCHARGE AND ROOT COHESION It is necessary to account for the weight of the large trees growing on the slope ground in the stability modeling. The tree weight (surcharge) increases the downslope weight of the soil mass and consequently decreases the stability of the slope. We have used a tree surcharge of 30 psf based on the calculation of the weight of a large conifer tree (18,000 pounds) distributed over the area of its root wad (a circular area approximately 25 feet in diameter). It is well understood that the tree roots on a timbered slope increase the overall strength of the shallow soil. This increase of soil strength is termed root cohesion and is an additive factor to the inherent cohesion of the mineral soil. Schmidt and others (2001)Z have estimated the root cohesion associated with industrial and natural coniferous forests in the Oregon Coast Range. They estimate that root cohesion in an industrial (second growth) forest having a significant understory ranges from 6.8 to 23.2 kilo Pascals (142 to 484 psf). We have used a mid-point value to model the stability of the existing timbered slopes by assuming root cohesion of 300 psf in our stability modeling, as indicated in Table 1 . Ziemer and Swanston (1977)1 indicate that smaller diameter roots lose strength within two years after a hemlock or Sitka spruce is cut, and the larger diameter roots of these species lose approximately 50 percent of their strength at 10 years after cutting. Ziemer (1981)1 provides an estimate for the net reinforcement of a soil layer resulting from root decay of cut trees and root growth of re-sprouted trees in clear cut forests. He found that the net reinforcement in a clear cut area decreases to approximately 50 percent of the original (pre-harvest) root strength after 2 years and to approximately 80 percent of the original strength after 10 years. He found that the highest vulnerability to slope failure primarily resulting from a loss of root strength is centered at 10 years after harvest and that regrowth of the forest increases the root strength to pre-clear cut levels after approximately 20 years. We are assuming that the timber harvest proposed for the Hama Hama gravel pit is the initial action in development of the mine and will be followed by stripping and stockpiling of topsoil and subsequent gravel resource extraction. Consequently, we anticipate that mine development will have proceeded to the extraction phase within two years of the proposed timber harvest. Based on these assumptions regarding the timing of timber harvest and mine development,we reduce the root cohesion by 50 percent, to a value of 150 psf, to represent the degradation of root strength two years after timber harvest. Also, we reduce the tree surcharge to zero to correspond to the removal of the trees during harvest. We also consider the worst-case where root strength drops to 20 percent of its original level (60 psf), corresponding to 10 years after clear cutting (Ziemer, 1981). z Schmidt, K. M.; Roering,J.J.;Stock,J. D.;Dietrich,W. E.; Montgomery,D. R.;Schaub,T., 2001, The variability of root cohesion as an influence on shallow landslide susceptibility in the Oregon Coast Range:Canadian Geotechnical Journal,V. 39,p.995-1024. Zeimer R.R.;D.N.Swanston, 1977,Root strength changes after logging in Southeast Alaska. PNW-306, 10 p.,Portland, Oregon: Pacific Northwest Research Station,U.S.Forest Service. Ziemer, R.R., 1981,The Role of Vegetation in the Stability of Forested Slopes: U.S.Forest Service, Pacific Southwest Forest and Range Experiment Station, 1981 International Union of Forest Research Organizations,World Congress,Japan, pp. 297-307. MDESIGN= 3 HamaHama-1-02:091911 SLOPE STABILITY MODELING We performed slope stability modeling of the site using the computer program DLISA(version 1.02), which was developed by the U. S. Forest Service (Hammond and others, 1992)1. The program implements the infinite slope equation and is appropriate in determining a factor of safety for shallow landslides occurring on natural forested slopes. Because DLISA assumes a landslide slip plane that is parallel to the ground surface, it provides a more conservative assessment (yielding a lower factor of safety) than the Simplified Bishop Method, in which the failure surface is allowed to have curvature at either end in order to intersect the ground surface. Figure 1 indicates that the slopes within the pro osed timber harvest area ra nge a from less than 20 percent to over 100 percent, with the steepest slope gradient at approximately 120 percent. We have computed factors of safety using DLISA for slope gradients of 60, 80, 100, and 120 percent. Our slope modeling considers three separate cases: • Stability of existing slopes • Stability of slopes two years after harvest (assuming a 50 percent reduction in root cohesion) • Stability of slopes 10 years after harvest (assuming an 80 percent reduction in root cohesion) We have summarized the parameters input into DLISA in Table 1 for each of these three cases. Table 1. Summary of Input Parameters to DLISA Soil Parameter Existing 2 Years Post- 10 Years Post- Condition Harvest Harvest Soil Depth (feet) 3.0 3.0 3.0 Depth to Groundwater(feet) 1.5 1 .5 1.S 0(degrees) 30 30 30 C(psf) 40 40 40 Root Cohesion (psf) 300 150 60 Tree Surcharge (psf) 30 0 0 Soil Unit Weight(pcf) 126.5 126.5 126.5 We used the parameters summarized in Table 1 as input to DLISA and computed factors of safety for all three cases (existing conditions, and 2 and 10 years post-harvest) for slope gradients of 60, 80, 100, and 120 percent. The resulting factors of safety are reported below in Table 2. 5 Hammond,C.;Hall,D.; Miller S.;Swetik, P., 1992,Level I Stability Analysis(LISA)documentation for version 2.0:: U.S. Department of Agriculture, Forest Service Intermountain Research Station,Gen.Tech. Rep.INT-285,Ogden,UT, 190 p. MDESIGM 4 HamaHama-1-02:09191 1 Table 2. Summary of DLISA Slope Stability Modeling Slope Gradient Factor of Safety Factor of Safety Factor of Safety (percent) (existing (2 years (10 years condition) post-harvest) post-harvest) 60 2.40 1.71 1.23 80 2.06 1.44 1.01 100 1.91 1.31 0.89 120 1.87 1.25 0.83 CONCLUSIONS AND RECOMMENDATIONS The results of the slope stability modeling indicate that the existing slopes are stable, which is consistent with our field observations. The decreases root cohesion predicted for two years after timber harvest results in a decrease in the factors of safety for slopes exceeding 60 percent. However, these decreased factors of safety indicate that even the steepest slopes (120 percent) will remain stable with an acceptable range based on the use of the infinite slope equation modeling. However, the slope stability modeling indicates that slopes exceeding 80 percent would become unstable 10 years after timber harvest, with the computed factors of safety falling below one. Based on the results of our field observations and slope stability modeling, we conclude that timber harvesting can be conducted everywhere within the proposed area shown on Figure 1 as long as mine development is initiated within two years after harvest. If mine development is delayed beyond a two-year period, then we recommend that the timber harvest be limited to slopes less than 80 percent as indicated on Figure 1. These steeper areas can be logged as part of the soil stripping activities that are the first phase of mine development. LIMITATIONS We have prepared this report for use by the Hama Hama Company in its development of the gravel pit planned for the site. Our report, conclusions, and interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with the generally accepted practices in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. WNDESIGW; S HamaHama-1-02:09191 1 We appreciate the opportunity to be of service to you. Please give us a call if you have questions. Sincerely, GeoDesign, Inc. Wash . Stephen P. Palmer, L.E.G. Principal Engineering Geologist ��Erv3ine�ing C,z-�l�'rt �1. SPP:kt 0 326 Attachments Se�/ O Opp Two copies submitted Document ID:HamaHama-1-02-091 91 1-geolr.doc STEPNEN P. P�LPr1�R ©2011 GeoDesign,Inc. All rights reserved. MODESIGM 6 HamaHama-1-02:09191 1 r FIGURES �, '•��•--. � ••• .�I Ifs GEo � • &jqj I LO-91 ATTACHMENT [! i DESIGNz' July 14, 2009 Hama Hama Company 301 North Webb Road Lilliwaup,WA 98555 Attention: Mr. David Robbins Report of Reclamation Plan Slope Stability Evaluation Hama Hama Gravel Pit Mason County,Washington GeoDesign Project: HamaHama-1-01 INTRODUCTION We have completed our slope stability evaluation for the surface mine reclamation plan of the Hama Hama Gravel Pit located in Mason County,Washington. The location of the site in relation to the surrounding vicinity is shown on Figure 1. The purpose of our services is to fulfill Mason County Departmen t of CommunityDevelopment requirements and to support the surface mine reclamation permit application to the Washington Department of Natural Resources (WADNR). recta pp P The results summarized in this report will be used in completing the Submittal Checklist for a Geotechnical Report provided by the Mason County Department of Community Development. In art of the mine permit application. addition,this report will be su bmitted to the WADNR as p add p SCOPE OF SERVICES The objective of our services was to characterize the geological and geotechnical factors at the site and complete an evaluation of slope stability for the post-mining reclamation. We have reviewed existing geologic information for the Hama Hama Gravel Pit and vicinity, conducted a geologic reconnaissance of the on-site slopes and geological conditions, and performed slope stability modeling to support the mine reclamation plan. SITE CONDITIONS SURFACE CONDITIONS The site is located immediately west of U.S. Highway 101 (US 101) and south of the Hamma Hamma River in northeastern Mason County,Washington. The mine permit area, shown on Figure 2, is roughly triangular is shape and lies within the larger property ownership of the Hama 6M= 1 SS75 SW Sequoia i kwv-Suite 100 1 Portland.OR 97224 I on 503.968.8787 1 t-503.968.3068 Hama Company. The majority of the mine permit area is located on a relatively level upland terrace at an elevation of approximately 300 feet above mean sea level (MSL). A relatively steep slope that descends from this terrace to US 101 parallels the eastern boundary of the permit area. The northwestern permit area boundary drops from the upland terrace into an elongated, closed depression at an elevation of approximately 100 feet above MSL The ground surface rises slowly south of the mine permit area to an elevation of 400 feet above MSL and higher. The site is covered by a mature second growth conifer forest having a brushy groundcover. A number of gravel or earth logging roads traverse the site, allowing for relatively easy access to the upland terrace area. No perennial streams cross or flow from the upland terrace, but two intermittent drainages dissect the eastern slope, as shown in the existing contours on Figure 2. Ponds, seeps, or areas of wet ground were not observed during our field reconnaissance. An approximately 1 acre area at the northern end of the steep east-facing slope has been sporadically mined for gravel borrow, and is currently a barren gravel slope with a grade of approximately 38 degrees that rises approximately 250 feet in elevation from the floor of the gravel pit to the slope crest. SITE GEOLOGY The site is located on the boundary between the Puget-Willamette Trough and Olympic Mountain uplift. Bedrock in the site vicinity consists of the lower to middle Eocene (55 million to 41 million years old)Crescent Formation (Gerstel and Lingley, 2003). In the vicinity of the site the Crescent Formation is primarily composed of basalt flows with interbeds of volcanic breccias,tuffs, sedimentary rock, limestone, and chert. The Crescent Formation bedrock is overlain by late Pleistocene(approximately 13,000 year old) glacial outwash deposited during the Fraser Glaciation (Carson, 1976). The glacial outwash is composed of sandy gravel containing cobbles and boulders deposited in a glacial lake delta environment. Along the steep slope bordering the eastern permit area boundary the outwash deposit exhibits forest bedding that dips approximately 36 to 38 degrees east. Nearly horizontal topset bedding caps the upper part of the steep slope and is exhibited in the relatively flat topography of the upland terrace. The steep slopes on the eastern part of the mine permit area are rated as unstable and the upland terrace as stable (Washington Department of Ecology, 1980). The northern corner of the triangular permit area is mapped as an unstable older landslide, which is younger than the recession of the Fraser Glaciation but has no historic occurrences of landsliding. Gerstel and Lingley(2003) does not show any mapped landslides within the mine permit area. FAULTING AND SEISMICITY Subduction of the Juan de Fuca Plate beneath the western margin of the North American Plate presents the potential for great(magnitude greater than 8) plate interface earthquakes. Paleoseismic investigations indicate that plate interface earthquakes have an average recurrence of 500 to 600 years and that the last subduction zone earthquake occurred in the year 1700. Moderate intensity, long duration ground shaking would be expected in the Puget Sound region in the event of a large magnitude Cascadia plate interface earthquake. Three distinct faults that have evidence of earthquake activity during the Holocene (10,000 years old to present)are located within approximately 15 miles from the site(Brocher and others, MDESIGNY 2 HamaHama-1-01:071409 I 2004;Johnson, 2004; Lidke, 2003a). Theses faults are the Tacoma, Seattle, and Saddle Mountain faults. The Hood Canal Fault,with inferred Quaternary(2.6 million years old to present)activity, is mapped along the axis of Hood Canal (Udke, 2003b). There is no evidence of earthquakes occurring on this fault during the Holocene. As part of the National Seismic Hazard Mapping Program, the U.S. Geological Survey(USGS) provides probabilistic earthquake ground motions for application in seismic design for engineering applications. For the Hama Hama Gravel Pit site, USGS predicts that a peak ground acceleration (PGA) of 0.32 g has a 10 percent probability of exceedance in 50 years, corresponding to a 475-year return period (USGS, 2006a). Deaggregation of the earthquake sources contributing to this ground motion estimate indicate that approximately 22.5 percent of the contribution comes from random crustal seismicity not related to known fault structures (USGS, 2006b). Slightly over 55 percent of the ground motion contribution is associated with deep Benioff zone earthquakes located within the subducting Juan de Fuca plate. The remainder of the ground motion contribution is related to seismicity on other crustal faults and Cascadia Subduction Zone plate interface earthquakes. SITE RECONNAISSANCE We conducted a reconnaissance of the landslide area on April 20, 2009 to observe geologic and slope stability conditions at the site. We observed outcrops of the glacial outwash gravel in a borrow area located on the steep, east-facing slope at the north end of the permit area. In this borrow pit the exposed gravel is distinctly bedded and the bedding dips at approximately 36 to 38 degrees east. We observed a number of shallow landslides on this steep slope located west of US 101 and south of the borrow pit. There were no large conifers or deciduous trees growing on the lower portion of the slopes immediately above the highway within the areas of shallow landsliding. We understand that this stretch of the highway was widened and that the lower portions of the slopes were cut back as part of this construction. We did not observe any evidence of instability or landsliding on the upper parts of the slope above US 101 or in the areas outside of the slopes cut as part of the highway widening. The eastern half of the upland terrace rises approximately 20 feet in elevation on a moderately steep slope to form a secondary terrace. The northern edge of the permit boundary is located at the base of a relatively steep slope formed in the outwash gravel. We observed a shallow landslide involving fill on the down-slope side of a logging road but no evidence of instability in the undisturbed natural slopes. We did not observe any evidence of deep-seated landsliding in the northern portion of the mine permit area mapped as an unstable older landslide by Washington Department of Ecology(1980). SUBSURFACE CONDITIONS We have reviewed the logs of five borings (B-1 through B-5)that we understand were drilled within the mine permit area in the early 1970s. The logs of these borings are included in the Attachment of this report, and the approximate locations of these borings are shown on Figure 2. The borings encountered predominantly sand and gravel to elevations of 130 feet above MSL or below. Boring B-4 encountered sand and gravel to an elevation of 72 feet above MSL where the boring was terminated in the sand and gravel unit. Based on the proximity of B-4 MDESIGNY 3 HamaHama-1-01:071409 to the sand and gravel outwash exposed on the eastern slope of the permit area, this unit presumable extends to an elevation of 20 feet above MSL, the approximate elevation of US 101. Two water wells (W-1 and W-2)were located immediately north of the mine permit area, as shown on Figure 2. The copy of the log of well W-1 (Unique Ecology Well ID Tag No.ALH943) is included in the Attachment. Well W-2 is an old, shallow well (approximately 40 feet deep)with a static groundwater elevation at approximately the level of Hood Canal. We understand that during very high tides the water in this well becomes brackish, indicating direct communication with sea water. The static groundwater level in W-1, drilled in 2007, was reported on the well log at approximately elevation 10 feet above MSL. STABILITY ANALYSIS OF RECLAIMED MINED SLOPES A stability analysis was performed along three separate cross sections (B-B', C-C', and D-D')that were placed to evaluate worst case slope stability conditions within and adjacent to the mine permit boundary. The locations of these cross sections are shown on Figure 2. All slope stability analyses presented in this report are based on the Simplified Bishop method and were performed using the computer program SLOPE/W, Version 7.13. BACK-CALCULATION OF SOIL STRENGTH PROPERTIES Soil strength parameters were estimated using back-calculation of the existing slope of the borrow pit using the existing topography along cross section B-B'. The existing topographic contours are shown in green on Figure 2. Based on our field observations, the slope of the borrow pit is stable with respect to deep-seated landslide failure and is marginally stable with respect to failures occurring within the near-surface material. Based on our field review and boring logs, we have modeled the entire subsurface as consisting of a single soil unit composed of well-graded, sandy gravel having a unit weight of 125 pounds per cubic foot(pcf). Based on our evaluation of nearby water wells,the static groundwater surface was assumed to be at the elevation of Hood Canal (0 feet MSL) in the slope stability model. The soil strength parameters summarized in Table I are based on the results of our back-calculation. Under these conditions the existing borrow pit slope has a static factor of safety(FOS) of 1.3 and is marginally stable (FOS= 1.0) under seismic loading using a pseudo-static coefficient of 0.15. The past approach to mining in the borrow pit involved cutting a near-vertical face at the toe of the existing slope with an excavator. The removal of the toe support would result in shallow sliding of the up-slope gravel soil so that it would cascade to the pit floor. The material could then be collected with a front-end loader and used as common borrow. To test of our back- calculated strength parameters,we introduced a 20-foot-tall cut having a grade of 1 horizontal to 1 vertical (H:V) at the toe of the existing slope to simulate the excavator cut used to dislodge the near-surface gravel. The results of our modeling indicated that this cut caused a shallow slope failure that would slough material into the pit floor, consistent with our understanding of the past mining approach. ®DIESIGNY 4 HamaHama-1-01:071409 Table 1. Back-Calculated Soil Strength Parameters Unit Weight Cohesion Internal Friction Angle Soil Unit (per (psfl (degrees) Well-graded, sandy gravel 125 75 39 STABILITY OF RECLAIMED SLOPE ALONG CROSS SECTION B-B' We performed slope stability modeling of both the eastern and western slope sides of the proposed mine reclamation along cross section B-B' using the soil strength parameters shown in Table 1. The proposed topographic contours for the slope reclamation are shown in red on Figure 2 and indicate that the redaimed slope rises from the floor of the existing borrow pit to a slope crest at an elevation of 100 feet above MSL Consistent with our back-calculation model, the entire subsurface is assigned to a single soil unit composed of well-graded, sandy gravel and the static groundwater surface was set to an elevation of 0 feet MSL. We have extended the toe of the potential slip surfaces in our analysis to include the road prism of US 101 and the tidal flat area below the highway. The results of our stability modeling of the eastern reclaimed slope along cross section B-B' are shown on Figure 3. A minimum FOS of 1.5 was obtained for the static condition and a minimum FOS of 1.1 was obtained under seismic loading using a pseudo-static coefficient of 0.1 S. These FOS' are higher than those computed for the existing slope in the back-calculation, primarily because the reclaimed slope is approximately 140 feet lower in elevation. The results of our stability modeling of the western reclaimed slope along cross section B-B' are shown on Figure 4. A minimum FOS of 3.0 was obtained for the static condition and a minimum FOS of 1.9 was obtained under seismic loading using a pseudo-static coefficient of 0.15. The reclaimed western slope is at a grade of 3H:1 V, which is significantly shallower than the eastern slope. STABILITY OF RECLAIMED SLOPE ALONG CROSS SECTION C-C' We performed slope stability modeling of both the eastern and western slope sides of the proposed mine reclamation along cross section C-C' using the soil strength parameters shown in Table 1. The proposed topographic contours for the slope reclamation are shown in red on Figure 2 and indicate that the reclaimed slope rises from the level of US 101 at an elevation of approximately 20 feet above MSL to a slope crest at an elevation of 110 feet above MSL. Consistent with our back-calculation model, the entire subsurface is assigned to a single soil unit composed of well-graded, sandy gravel, and the static groundwater surface was set to an elevation of 0 feet MSL We have extended the toe of the potential slip surfaces in our analysis to include the road prism of US 101 and the tidal flat area below the highway. The results of our stability modeling of the eastern reclaimed slope along cross section C-C'are shown on Figure 5. A minimum FOS of 2.7 was obtained for the static condition and a minimum FOS of 1.8 was obtained under seismic loading using a pseudo-static coefficient of 0.15. These FOS' are higher than those computed on the reclaimed slope along cross section B-B' because the slope along this section line is shallower. MODESIGNZ 5 HamaHama-1-01:071409 The results of our stability modeling of the western reclaimed slope along cross section C-C' are shown on Figure 6. A minimum FOS of 3.0 was obtained for the static condition and a minimum FOS of 1.9 was obtained under seismic loading using a pseudo-static coefficient of 0.15. These results are comparable to the results of the modeling of the western reclaimed slope on cross section D-D', as shown on Figure 4. STABILITY OF RECLAIMED SLOPE ALONG CROSS SECTION D-D' We performed slope stability modeling of the north-facing slope of the proposed mine reclamation along cross section D-D' using the soil strength parameters shown in Table 1. The proposed topographic contours for the slope reclamation are shown in red on Figure 2 and indicate that the reclaimed slope rises from the level of the final pit floor at an elevation of approximately 40 feet above MSL to a slope crest at an elevation of 320 feet above MSL. Consistent with our back-calculation model, the entire subsurface is assigned to a single soil unit composed of well-graded, sandy gravel, and the static groundwater surface was set to an elevation of 0 feet MSL. We have extended the toe of the potential slip surfaces in our analysis to include a significant portion of the pit floor and the area behind the slope crest. The results of our stability modeling along cross section D-D' are shown on Figure 7. A minimum FOS of 2.8 was obtained for the static condition and a minimum FOS of 1.8 was obtained under seismic loading using a pseudo-static coefficient of 0.15. These FOS' are slightly lower than those computed on the reclaimed slope along cross sections B-B' and C-C' because the slope along this section line is significantly taller. CONCLUSIONS AND RECOMMENDATION In our opinion,there are no landslide hazard areas within the proposed mine permit area or adjacent to the permit area that could impact the site. This conclusion is based on our review of the available geologic reports and maps, logs of borings and water wells, field reconnaissance, and slope stability modeling. In fact,the lowering of the steep slope adjacent to US 101 resulting from mine development will increase the stability of this slope. Consequently, final reclamation of the Hama Hama Gravel Pit will decrease the potential landslide hazard both on site and off site. Based on our slope stability evaluation, structural mitigation will not be required as part of the mine reclamation. Based on our evaluations,we make the following recommendations: 1. We have not identified any landslide hazard areas within or directly adjacent to the mine permit area. Consequently, landslide hazard area buffers do not need to be defined. 2. Temporary roads used to support mining activities should have a minimum 10-foot setback from the edge of existing or reclaimed slopes. Slope setbacks for permanent roads, structural foundations, and fills should be determined through a site-specific geotechnical evaluation. 3. Drainage features, such as settlement ponds or septic drain fields, should not be located on or behind slopes unless a site-specific geotechnical evaluation determines that this action will not result in instability of the slope. ®DESIGN`f 6 HamaHama-1-01:071409 4. A clearing and grading plan and temporary and long-term erosion control plans should be developed as part of the surface mine reclamation permit application. The intent of these plans is to minimize on-and off-site impacts resulting from erosion of slope destabilization. These plans should be reviewed by a civil engineer or engineering geologist licensed in the state of Washington. LIMITATIONS We have prepared this report for use by the Hama Hama Company and its reclamation planning team. Our report, conclusions, and interpretations should not be construed as a warranty of the subsurface conditions and are not applicable to other sites. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with the generally accepted practices in this area at the time this report was prepared. No warranty or other conditions, expressed or implied, should be understood. We appreciate the opportunity to be of service to you. Please give us a call if you have questions. Sincerely, GeoDesign, Inc. o� W a S A Ike rb Stephen P. Palmer, L.E.C. t Senior Associate Engineering Geologist Erpnewn-,c_.: , h 26 �`6, Geo ✓✓ ' V STEPHEN P. PALMER Scott V. Mills, P.E. Principal Engineer cc: Mr. Bryan Allison, Garrison Resource Group (two copies) SPP:SVM:kt Attachments One copy submitted Document ID:HamaHama-1-0 1-071409-geolr-doc O Z009 GeoDesign,Inc. All rights reserved. MDESIG N= 7 HamaHama-1-01:071409 REFERENCES Brocher, T.M., Sherrod, B.L.,Johnson, S.Y., Blakely, R.J., and Lidke, D,J., compilers, 2004, Fault number 581,Tacoma fault, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/regional/gfaults, accessed 06/11/2009. Carson, R.J., 1976, Geologic map of north-central Mason County,Washington: Washington Division of Geology and Earth Resources Open File Report 76-2, 1 sheet, scale 1:62,500 Gerstel,W. J.; Lingley,W.S.,Jr., 2003, Geologic map of the Mount Olympus 1:100,000 quadrangle,Washington:Washington Division of Geology and Earth Resources Open File Report 2003-4, 1 sheet, scale ]:100,000. Johnson,S.Y., compiler, 2004, Fault number 570,Seattle fault zone, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/regional/qfaults, accessed 06/11/2009. Lidke, Dj., compiler, 2003a, Fault number 575, Saddle Mountain faults, in Quaternary fault and fold database of the United States: U.S.Geological Survey website, http://earthquakes.usgs.gov/regional/qfaults, accessed 06/11/2009. Lidke, D,J., compiler, 2003b, Fault number 552, Hood Canal fault zone, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/regional/gfaults, accessed 06/11/2009. USGS, 2006a, 2002 National Seismic Hazard Map Interpolated Probabilistic Ground Motion for the Conterminous 48 States by Latitude Longitude, 2002 Data: U.S.Geological Survey website, http://egint.cr.usgs.gov/eq-men/html/lookup-2002-interp-06.html, accessed 06/10/2009. USGS, 2006b, 2002 National Seismic Hazard Map Interactive Deaggregations: U.S. Geological Survey website, http://egint.cr.usgs.gov/eq-men/htmi/deaggint2002.html, accessed 06/10/2009. Washington Department of Ecology, 1980, Coastal zone atlas of Washington;volume 9, Mason County: Washington Department of Ecology, 1 v., maps, scale 1:24,000. MDESIGN= 8 HamaHama-1-01:071409 FIGURES I A � { I CJS NJ N INS" t I 1 � v r O \ LL ' d SITE ti �nl ilk � \ \ JV Ko \� N ° _ ,� - \ 0 �— \ 0 2000 4000 E USGS QUADRANGLE MAP d = MAP CREATED WITH TOPO!• o E C2007 NATIONAL GEOGRAPHIC \ (SCALE IN APPROXIMATE FEET) HAMAHAMA-1.01 VICINITY MAP DESIGN a 15575 SW Sequoia Parkway-Suite 100 z raciaoa Olt 97224 HAMA HAMA GRAVEL PIT FIGURE 1 c „ OfS03.9%e.a7t7 Fax S03.963.30e8 1ULY 2009 MASON COUNTY,WA d N W .� U --------•-•-------•--- i �• i EXPLANATION i W-2 '-- PERMIT BOUNDARY a ui Bl PROPERTY LINE '^ uZ RECLAIMED CONTOURS �. o j ! EXISTING CONTOURS = j B-1 • BORING I 1 1 j 1 W-1 • WATER WELL i ! ! 6 B' j 0 B- ! �J CROSS SECTION � 1 1 1 i C 1 C� i i B-3 1 Q °' 8 a } i = i i N 2S N� 4 _. ------- N ,- _ Q ` - _•- - -•- - _ _,_-_. 11 ,000 500 0 1 ,000 4i D (SCALE IN FEES {I E Y File Name:HamaHama-1-01-F3.doc PrlmDate: 06/19/09 200 180 CROSS SECTION B-B' STATIC 160 140 120 1_5 • 100 O 80 > N 60 W 4CI 20 0 ------------------------------------------------------------------ -20 -40 -60 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 Distance (x 1 000) STATIC CONDITION 200 180 CROSS SECTION B-B' 160 SEISMIC 140 1 .1 120 • 100 O 80 N 60 W 4 20 0 ---------------------------------------------------------------- -20 -40 -60 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 Distance (x 1 000) SEISMIC LOADING DESIGN? " "AMA-1-01 SLOPE STABILITY MODELING - B-B' EAST SLOPE 1S575sw5ewolApwkway wileloo lenland8787 OR F-% 1 ULY 2009 HAMA HAMA GRAVEL PIT FIGURE 3 oa so3.�a.a�a� fax so3.96a.to6a MASON COUNTY,WA File Name:HamaHama•1-01•F4.doc Prim Date: 06/19/09 200 180 CROSS SECTION B-B' STATIC 160 140 3_0 120 100 /1 O 80 J, N 60 4 _- 20 0 -------------------------------------------------------------------- -20 -40 -60 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 Distance (x 1000) STATIC CONDITION 200 180 CROSS SECTION B-B' 160 SEISMIC 140 1_9 120 + 100 O <�% 80 lam.; 60 ! , 4 20 0 -------------------------------------------------------------------- -20 -40 -60 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 Distance (x 1000) SEISMIC LOADING DESIGN= "AMAHAMA-1-01 SLOPE STABILITY MODELING - B-B'WEST SLOPE 15575 SW Sequoia Pmkvay-Suke 100 Ponlaw OR 97224 JULY 2009 HAMA HAMA GRAVEL PIT Off503.968.8787 Fax 50a.968.3oea MASON COUNTY,WA FIGURE 4 File Name:HamaHama-1-01-FS.doc Print Date: 06/19/09 e 200 CROSS SECTION C-Cl STATIC 160 2_7 120 80 O to 4 W 0 ------------------------------------------------------------------ —40 —80 —120 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Distance (x 1 000) STATIC CONDITION 200 CROSS SECTION C-Ce 160 SEISMIC 1_8 120 • 80 C � O 4 0 ------------------------------------------------ ., -40 -80 -120 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Distance (x 1 000) SEISMIC LOADING �DESIGNIV HAMAHAMA-1-0 1 SLOPE STABILITY MODELING - C-Cl EAST SLOPE 1 SS7S SW Sequoia Pathway-Suite 100 Poniard "'?2403. JULY 2009 M�ASONN COUNTY,WA T FIGURE 5 OR 503.968.8787 Fax 503.968.3068 File Name:HamaHama-1-01-F6.doc Prim Date: 06/19/09 200 CROSS SECTION C-Cl 160 STATIC 3.0 120 # 80 - 0 f/ M 401 N W 0 ------------------------------------------------------------------ -40 -80 -120 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Distance (x 1000) STATIC CONDITION 200 CROSS SECTION C-C' 160 SEISMIC 1_9 120 # 80 O > 4 N W o ------------------------------------------------------------------ -40 -80 -120 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Distance (x 1000) SEISMIC LOADING DESIGN= "AMAHAMA-1-01 SLOPE STABILITY MODELING - C-C' WEST SLOPE 1557S SW Sequoia Parkway-Suite 100 Portland OR 97224 DULY 2009 HAMA HAMA GRAVEL PIT FIGURE 6 Off 503.968.8787 Im 503.968.3068 MASON COUNTY,WA File Name:HamaHama-l-01-F7.doc Print Date: 06/19/09 400 2.8 360 CROSS SECTION D-D' 320 STATIC 280 240 200 C 160 O 120 N W 80 40 0 -------------------------------------------------------------------------------------------------- -40 -80 -120 -160 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Distance (x 1000) STATIC CONDITION 400 1.8 360 CROSS SECTION D-D' SEISMIC 320 280 240 200 - r, 160 O � 120 ~� Ill 8o 40 0 -------------------------------------------------------------------------------------------------- -40 -80 -120 -160 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Distance (x 1000) SEISMIC LOADING DESIGN`= HAMAHAMA-1-0 1 SLOPE STABILITY MODELING - D-D' NORTH SLOPE 15575 SW Sequoia Parkvwy-Suite 100 -T ftnWW OR 97274 DULY 2009 HAMA HAMA GRAVEL PIT FIGURE 7 Off 503.%8.8787 Fax 503.%8.3068 MASON COUNTY,WA ATTACHMENT t 11 39 • }��,„ 3L�_ s��,. j{`,y��.�.' -- - - �� - � _ .•OAT .. .. .t.C� ..: ...„ � �' --- .� O � �•r s• I:':- S G; Sit .1 X1 . IL -- : .. ... 00 'L- WATER WELL REPORT ,.,. Orlglnal&I" copy-Ecology.2sacopy-owner. 34 copy-driler CURRENT f i:�e 1 Il•1 Notice of Intent No.WE06296 Construction/Decommission(Yin circle) '7� 570 QX Construction Unique Ecology Well ID Tag No. ALH943 Fj Decommission ORIGINAL INSTALLATION Water Right Permit No. EXEMPT WELL Notice oflntentNumbe► Property Owner Name DAVE ROBBINS PROPOSED USE: ❑a Domestic ❑Industrial []Municipal DcWaicr 0 Irrigation ❑Test Well ❑Other Well Street Address 35957 HWY 101 TYPE OF WORK:Owneesnumber o(well(ifmore than one) City LILLIWAUP County MASON ❑a New well ❑Recondilioned Method: ❑Dug ❑Dorm ❑ Driven ❑ %pe ed ❑Cable i]Rot celled Location NE 1/4-1/4SW 1/4 See27 Twn24N R 3W- ❑ Checkor . DIgtENS10NS:Diametercfwdl inches,drillod it (s,t,r Still REQUIRED) WWM❑. One D th of com lend well 65 R CONSTRUCTION DETAILS Lat/Long Lat Deg Lat Min/Sec Casing 9 Welded 6 Diam.from+I A.to 6_ ft. InstA*d: [I Liner installed Dia m ft.from to R. Long Deg Long Min/Sec ❑Threaded Diam,From R.to fl. Tax Parcel No.(Required)324270000010 Perforattem: ❑Yes ❑Q No — CONSTRUCTION OR DECOMMISSION PROCEDURE Type of perforator used Formation:Describe by color,character,size of material and structure.and the kind and SIZE orpera in.by in and no,of perfs from ft to fl nature of the material in each stratum penetrated,with at least one entry for each change ofinformation.(USE ADDITIONAL SHEETS IF NECESSARY.) Scf-- Ayes ❑No 9K-Pac Location 57.6 FROM TO Manufacturers Name .IOIINS6N MATERIAL Type SLOTTED Model No SILTY SAND AND GRAVEL O 5 Dimn.5 Slot size 030 from 60 ft.to 65 ft. BROWN SILTY CLAY 5 12 Dim, SM size, Ran ft.to ft. BROWN SILT BOUND SAND AND GRAVEL 12 25 Cisavel/FRterpacked- ❑ Yes ❑Q No Sizeofgravd/sand GRAY SILTY CLAY 25 1 45 Materials placed from ft to ft. BROWN MEDIUM TO COARSE SANDY 4S GRAVEL.LOOSE,WATER 67 Surface Seal: Q Yes ❑ No To what depth? 20 ft. GRAY CLAY 167 70 Material aced is sal BENTONITE CHIPS Did any strata contain unusable water! ❑Yes Q No Type of water? Depth of strata Method of sealing strata off PUMP:Manufacturers Name Type: H.P. WATER LEVELS:Wnd-surface elevation above mean sea level ft. Static level 27 ft.below top of wcli Date 818/07 Artesian pressure lbs.per square inch Date Artesian water is controlled by (cap,valve,etc.) WELL TESTS:Drawdown is amount water level is lowered below static level Was a pump test mado? ❑ Yes i] No Ifyes,try whum? Yield: gal./min.with ft drowdown after hrs. j Yield. galhnin.with ft.drowdown after hrs. -- Yield: gal./min.with ft drawdown after hrs. Recovery data(time taken as zero when pump turned o(f)(water level measured from well top to water level) Time Water Level Time Water Level Time Water Level ashitigion St itc AGgy- 63L/min.with ft.drawdown after hrs. Airtest 75 gallmin.with stem set at S0 ft,for I hrs Artesian flow g put Date /07 Tem,cramre of water 51 Was achartical analysis made? ❑ Yes Q No Start Date 8/7/07 Completed Date 8/R WELL CONSTRUCTION CERTIFICATION:I constructed and/or accept responsibility for construction of this well,and its compliance with all Washington well construction standards.Materials used and the information reported above are true to my best knowledge and belief QDriller❑Engineer❑Trainee Name(Pnnt)BRANDON HICKS Drilling Company ARCADIA DRILLING INC. DrilledErlgineerffrainee Signature O; a Address PO BOX 1790 Driller or trainee License No. 2785 City,State,Zip SHEI.TON WA 98584 IF TRAINEE:Drillees License No: Contractors Drillces Signature: Registration No. ARCADD1098KI Date W8/07 ECY 050-1.20(Rev 4107) Ecology is an Equal Opportunity Employer