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<br />,. <br /> <br />photographs of the affected areas, and computer printouts showing flood discharges, stage, <br />and velocities with respect to time. <br /> <br />5.7 Geotechnical Report - A geotechnical report is required that evaluates the suitability of the <br />foundation, stability of the dam and the slopes along the reservoir rim, and addresses issues <br />regarding suitability and quantity of material available for construction of the dam as designed. <br />The geotechnical report shaIl include, but not be limited to, the foIlowing: <br /> <br />5.7.1 Information on the geology of the local area and dam foundation for all classes of <br />dams. AdditionaIly, for all High Hazard dams and large Significant Hazard dams the report <br />shaIl include data on faults and fault history that may affect the dam, seismicity of the area, <br />and an evaluation of the reservoir perimeter landslide potential. <br /> <br />5.7.2 For High Hazard and Significant Hazard dams, foundation investigations shaIl include <br />driIling, to a depth 1.5 times the height of the dam or at least 10 feet into bedrock, <br />whichever is less; logs of borings and test pits; standard penetration or other field density <br />tests; field and laboratory classification of soils; measurement of the water level in each driIl <br />hole; in-situ permeability tests; gradation tests of foundation materials, especially at the <br />locations of proposed drains; determination of liquefaction potential; and whether clay type <br />foundation materials exhibit residual strength properties and dispersivity. <br /> <br />5.7.3 For High Hazard and Significant Hazard dams, the report shaIl document the <br />suitability of on-site borrow materials or other available sources to be used in construction. <br />The following information and data are required, as a minimum, to be included in the <br />Geotechnical Report. <br /> <br />1. Standard Property Tests and soil classification of all materials; <br /> <br />2. Compressibility and/or consolidation tests of soils; <br /> <br />3. Permeability of placed materials; <br /> <br />4. Shear strength of natural and placed materials (dynamic shear strength <br />tests if applicable); <br /> <br />5. Compaction tests; and <br /> <br />6. Identification of potentiaIly dispersive clays. <br /> <br />5.7.4 For Low Hazard dams, other than Minor size, the report shaIl include field <br />classification of soils, logs of borings and test pits, standard penetration test results, and the <br />requirements of Rule 5.7.8. The foundation exploration shaIl include drilling to a depth 1.5 <br />times the height of the dam or at least 10 feet into bedrock, whichever is less. <br /> <br />18 <br />