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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Geotechnical Engineering Investigation <br /> <br />ID. Field Investigation and Testing <br /> <br />A. General <br /> <br />Subsurface exploration was perfonned by Harza between August 4 and August 16, 1994. <br />Five (5) exploratory borings were drilled to a maximum depth of seventy (70) feet. Two inch <br />PVC, screened stand-pipes (piezometers) were installed in all borings. Penneability tests were <br />also attempted at regular intervals during drilling. Gradation tests were perfonned on soil samples <br />retrieved from the borings. <br /> <br />The approximate location of the borings are shown on the Plan View, Dam and Outlet <br />Conduit, Figure 3. Logs of the exploratory borings are included in Appendix A. The results of <br />our laboratory testing are presented in Appendix B. <br /> <br />B. Field Investigation <br /> <br />The field investigation consisted of a surface reconnaissance and a subsurface exploration <br />program using a track-mounted, diamond core, wireline drill rig. Five (5) 3-inch diameter <br />exploratory borings were drilled on August 4 and August 16, 1994, to a maximum depth of <br />seventy (70) feet. One boring, B-1, was drilled at an inclination of 45 degrees, the other four <br />were vertical. The approximate boring locations are shown on Figure 3, Plan View, Dam and <br />Outlet Conduit, The soil and rock encountered in the boring were continuously logged in the field <br />by our representative. The soils are described in accordance with the Unified Soil Classification <br />System (ASTM D-2487). The logs of the borings (B-1, B-2, B-3, B-3 A and B-4)) as well as a <br />key for the classification of the soil (Figure A-I) are included in Appendix A. <br /> <br />The elevation on the boring logs is based on the as built plans dated August 1932 and the <br />Dam and Outlet Conduit Plan View by Hydro-Triad, undated, and should be used only for <br />comparison between the borings. The approximate locations of the borings were determined by <br />taping from the existing piezometers and should be considered accurate only to the degree implied <br />by the method used. <br /> <br />A geologist/geotechnical engineer from Harza Northwest was present at the project site <br />throughout the drilling program to monitor the exploration, assist in the coring and sampling, and <br />prepare descriptive field logs of the conditions encountered at each exploration location. <br /> <br />Continental Dam <br /> <br />Page 6 <br />