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<br />Conclusions <br /> <br />"A. This study has shown that for a saturated aquifer exit <br />gradients large enough to cause piping would occur in the <br />absence of any relief drainage. A transient study may show <br />that these gradients will not develop in the time required to <br />lower the reservoir from the maximum water elevation down to <br />normal elevation. Unless this is shown by furthi!!r study, some <br />rel ief drainage will be required. <br /> <br />B. The beneficial effects of exit gradient reduction by the <br />impermeable slurry trench extend at the most to approximately <br />300 feet beyond the end of the trench. <br /> <br />" <br /> <br />C. A partial depth slurry trench is ineffective in reducing <br />high gradients for the geologic conditions modeled. <br /> <br />D. Pressure relief wells in combination with the proposed <br />slurry trench will provide adequate relief of large exit <br />gradients. Such a system may allow for a reduction in length <br />of the slurry trench if additional seepage losses to the river <br />can be tolerated. A toe drain . will also be required to <br />reduce horizontal gradients at the toe. <br /> <br />E. Well spacing rather than well depth should be checked for <br />economy when the final design is made. It was found in this <br />report and has been shown in previous works. . . that fully <br />penetrating wells are much more effective than partially <br />penetra t i ng we 11 sin thi s type of aqu i fer. " <br /> <br />Safety Review Panel <br /> <br />To review the feasibility embankment designs and the results of the <br />stability analysis, an independent review panel was established. Panel <br />members were selected from a list of private consultants with expertise <br />in embankment and foundation design and geology. The Bureau of Reclamation <br />and the Colorado Department of Natural Resources collaborated on the <br />list of nominees and agreed on the final selections. Commissioner <br />R. Keith Higginson and Assistant Secretary Guy Martin concurred in the <br />selections. The three private consultants who formed the independent <br />safety review panel were: <br /> <br />1. George Sowers, Law Engineering and Testing Consultants; experienced <br />in dam embankments and founda t ions. <br />2. Thomas Leps, Thomas ,Leps Company; experienced in dam embankments <br />and founda ti ons. <br /> <br />" <br /> <br />10 <br />