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<br />....;. .' <br /> <br />- :':,:-) <br /> <br />"-', <br /> <br />~ <br />co <br />1'\) <br />W <br /> <br />17. Degradation ranges below John Hartin Dam. The range system <br /> <br />was almost destroyed by the June 1965 flood but was reestablished during <br /> <br />the fall of 1966. TIlere are 13 monumented degradation ranges between the <br /> <br />dam and Lamar, Colorado, a distance of 23 miles. These ranges are a <br /> <br />part of the sediment observation program for the John Martin Reservoir <br /> <br />project and were established to measure changes below the dam attributable <br /> <br />to operation of the project. They are resurveyed.only when suhstantial <br /> <br />changes are apparent in the reach. This was in 1944, twice in 1945, 1951, <br /> <br />1962, 1966, and 1972. Land survey methods were used to determine the <br /> <br />profiles along each range. The amount of channel change was determined <br /> <br />by the end-area method assuming the change on each range was represent- <br /> <br />ative of the change halfway to the adjacent ranges. <br /> <br />SAMPLING <br /> <br />18. Suspended sediment sampling. Uaily suspended sediment sampling <br /> <br />at the inflow stations for John Martin Reservoir was discontinued in 1962. <br /> <br />Since then sampling at these stations has been on an intermi.ttent selective <br /> <br />basis by the U.S. Geological Survey. The outflow ~elow John Martin Dam <br /> <br />is sampled daily when releases are being made from the reservoir. <br /> <br />19. Riverbed and lake deposit sampling. Riv~r~ed samples were not <br /> <br /> <br />taken outside the boundary of John Martin Reservoir during the period <br /> <br />/1966-1972. Ouring the ~Iarch 1972 resurvey 14 samples of deposited mate- <br />j1rail were taken from the bottom of the reservoir above Range 5. An <br /> <br />I' 'additional 24 samples were taken between the dam and Range 5 in June 1972. <br /> <br />9 <br />