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<br />--) <br /> <br />~ <br />QCl <br />(.....) <br />m <br /> <br />original contour map (1936-1939) and 1951 range profiles. Calculations <br /> <br />for this report are based on the 1968 aerial survey volumes and on 1966 <br /> <br />range profile data. Subsequent reports will be based on these data. <br /> <br />48. The amount of bedload sediment carried into John Martin Reservoir <br /> <br />has been small. It has been about 5 percent of the tot al sediment load. <br /> <br />The resurvey of degradation ranges below John Martin Dam indicates a <br /> <br />total aggradation of 1,113 acre-feet since the original survey of degrada- <br /> <br />tion ranges in January 1944. Average aggradation for the period of observa- <br /> <br />tion has been 0.29 foot or about 0.01 foot per foot per year. <br /> <br />49. Conclusions. The following conclusions were derived from results <br /> <br />of the latest resurvey. The selective sampling program at the two inflow <br /> <br />stations to John Martin Reservoir will be continued on the same basis as <br /> <br />previously used and daily sampling of releases will be continued at the <br /> <br />outflow station. Annual corrections of the area-capacity table for the <br /> <br />lower 20,000 acre-feet of storage will be made with inflow and outflow data <br /> <br />or from estimated sediment deposition data. If necessary a partial survey <br /> <br />of the lower elevations of the reservoir will be made. <br /> <br />50. A resurvey of the degradation range system will ~e made when the <br /> <br />next complete range survey is made. The latest survey indicates a noticeable <br /> <br />change from the previously experienced pattern. From August 1944 through <br /> <br />October 1966 there was a small variable amount of degradation and between <br /> <br />October 1966 and March 1972 there was aggradation. The aggradation is <br /> <br />related to releases from John Martin neservoir which were relatively small <br /> <br />in volume but of extended duration. Large volume releases necessary to <br /> <br />22 <br />