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<br />, <br /> <br />. <br /> <br />. <br /> <br />At least one test pit shall be excavated in the dam foundation to obtain <br />laboratory samples and to investigate the suitability of the material as <br />a foundation. <br /> <br />Lake Avery - The subsurface investigation program at Lake Avery will <br />concentrate on determining the foundation characteristics of the upper <br />mantle of impervious soil on the left abutment. This will be <br />accomplished by drilling approximately 10 cased percussion/rotary drill <br />holes with associated standard penetration tests, permeability tests and <br />recovery of undisturbed samples. The holes will be drilled to the top <br />of the underlying gravel. The thickness of the overlying impervious <br />layer will be defined over the entire abutment area by correlating the <br />bore holes with seismic refraction. A seismic section will be run over <br />the gravel-filled channel on the right abutment, which for the highest <br />reservoir enlargements may become a saddle dam foundation or an <br />alignment for a spillway section. The objective will be to define the <br />top of rock profile. <br /> <br />The surficial geologic mapping of the site will include the diversion <br />dam site and pipeline alignment for the delivery system. If the mapping <br />reveals slumping or any other potentially hazardous foundation <br />conditions, subsurface investigation consisting of percussion holes and <br />seismic sections will be carried out. <br /> <br />Products resulting from this task shall be logs of all borings and test <br />pits, including the results of standard penetration and permeability <br />tests. Boxed core will be made available to the State for future <br />storage. A photographic record of this core will also be compiled. <br />Information from seismic refraction will be correlated with bore hole <br />information, in the form of geologic sections, structural contour and/or <br />isopack maps, as appropriate. Laboratory characterization of samples <br />obtained under this task will either be a part of the logs, or described <br />in a separate section of the final report. <br /> <br />A-10 <br />