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-12- <br />With a water storage level of 6.5 feet, the tower and catwalk would be raised to El. 3721.5. <br />The catwalk would be extended by adding an additional support and walkway section <br />extending to the dam crest. <br />Secondary outlet works would be installed on Dam 1 reconstruction alternatives for releases <br />to wetlands and the downstream reservoir, and on Dams 113 and 1 A -2 -313 new replacement <br />alternatives to release water from the storage created -by the new dam ,construction. <br />4.3 Geotechnical Data <br />Since 1978, a number of geotechnical and hydrological',`- ip"ave been performed for this <br />reservoir. These consist of drilled borings, test pits and laboratory testing. Packer tests were <br />performed in Dam 2 to estimate the seepage yin bedrock. Laboratory tests included <br />classification and strength tests. These data Were used to analyze the stability of the <br />embankments, for sizing berms, and determining the filter,gr.,adation requirements and sizing <br />drainage pipe. <br />The embankment for the new .construction and rehabilitation should be constructed with <br />upstream slopes of 3:1 and, downstream slopes of 2.5:1. The embankment should be <br />homogenous or zoned earthfill'dam; and should have an internal filter drain, including a chimney <br />drain to lower thep'tireatic surface: The foundation preparations would consist of removal of <br />all organic material and extending the seepage cutoff 5 feet deep into the unweathered portion <br />of the bedrock. The.: upstream slope can be steepened somewhat if soil cement slope <br />protection is used due to approximate 9 foot horizontal lifts used in construction of soil <br />cement. <br />A cut and cover, type of a cutoff trench is recommended for use as a cutoff in new <br />construction. In case of existing embankments, grouting or a slurry trench cutoff should be <br />considered. For the rehabilitation of the existing dams, downstream embankment construction <br />are the preferred method, as foundation conditions at the upstream toe of the existing <br />embankments are not known. It is anticipated that the upstream toe has considerable amount <br />Zreports 197 -1 -500.0 <br />