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<br />o <br />':1,::";' <br />I\j <br />00 <br />W <br />""-I <br /> <br />remove this accumulation of sediment were not needed for operational <br /> <br />procedures during the period covered by the latest resurvey. With <br /> <br />increased runoff there should be a'recurrence of large releases that <br /> <br />will alleviate this condition. Resurveys of ranges on tributaries with <br /> <br />elevations above noma 1 pool levels will be made when the reservoir has <br /> <br />been operated at high water surface elevations that cause deposition in <br /> <br />the tributaries. <br /> <br />51. Resurveys of the reservoir will be scheduled not only as the <br /> <br />result of the volume of inflow but also as the result of frequency of <br /> <br />floodflows. Paragraph 30 of the October 1967 report states almost 14,000 <br /> <br />acre-feet of sediment were carried into the reservoir in a ~-1/2 month <br /> <br />period during and subsequent to the 1965 flood. For the resurvey period <br /> <br />of 4.5 years from March 1962 to September 1966 this was almost 75 percent <br /> <br />of the sediment inflow during the period and occurred in only 6-1/2 <br /> <br />percent of the time. Proper scheduling of resurveys requires continuous <br /> <br />monitering of inflow volumes and flood frequencies. <br /> <br />52. Systematic sampling of sediment deposits for size and density <br /> <br />"Ii11 be continued. Samples were taken to a depth of 5 fee,t after the most <br /> <br />recent resurvey at the lower end of the reservoir and on both channel and <br /> <br />overbank in the upper end of the reservoir. This over all sample coverage <br /> <br />indicated'that the average density of 75.7 pounds per cubic foot should be <br /> <br />closer to 80.0 pounds per cubic foot. This change will be made if the <br /> <br />sampling during the next survey confirms the higher unit weight. Extreme <br /> <br />23 <br />