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<br />l . <br /> <br />ie <br /> <br />". <br />, ' <br />\_/ <br /> <br />n- <br /> <br />''---""' <br /> <br />,. ,........ (l <br />Ul!...'~ 'Backhoe pit investigated at site showed about 6 feet of <br />'material on a water-bearing sandy stratum. Extensive drainage <br />may be necessary to work entire borrow area. <br /> <br />,c. Additional cobbles and pebbles are desirable for the pervious <br />portion of the embankment and the concrete aggregate. <br /> <br />d. The fine sand and silt in the zone 2 material may cause it <br />to be nonfree draining. <br /> <br />e. Use three-dimensional model to examine slurry wall-relief <br />well ir.t~raction. <br /> <br />f. Sel;~icity is low but some data should be obtained to establish <br />the de~ee of intensity anticipated. <br /> <br />8. Additional 'items and suggested final design investigations <br />mentioned by Leps: <br /> <br />a. None of the potential pervious borrow material pointed out <br />to us during the field inspection would qualify as being pervious <br />or resistant to piping. <br /> <br />b. River bottom sources of sand and gravel would be recoverable <br />by dredging. <br /> <br />c. A substantial volume of clean, very. pervious gravel will be <br />required and no source was known to be locally available. <br /> <br />d. The fine silty sand borrow, south of the river, would be <br />"relatively brittle when normally compacted and relatively <br />sensitive to piping." It should be fully protected against <br />piping when used in dam. <br /> <br />e. Concerning hydrology Leps notes ". · · it is only remotely <br />probable that the reservoir would rise above elevation 4428.5 <br />more than once in the next 100 years." <br /> <br />f. ' Reservoir level would not be greater than 4428.5 for more <br />than about 7 days. <br /> <br />g. "..... h determined elevation 4428.5 as the reasonable <br />maximum design elevation of reservoir water surfaces for steady <br />seepage conditions" · .... this means that the reservoir .... · .. <br />could not possibly saturate the foundation of the long, right <br />abutment, noncutoff reach of the dam .. · .. to create steady-state <br />seepage conditions" · ." except at a few locations. <br /> <br />. <br />