Laserfiche WebLink
<br /> <br />from 1951 through 1957, during which the Reservoir was empty for over 700 days, was 13 per <br /> <br />c~)j"t. Thus it may be seen that for periods in which the river is allowed to flow through <br /> <br />the Reservoir practically unrestricted ~rom 75 to 87 per cent of the sediment is not <br />deposited but passed dOwn stream. Included in the report is the following statement: <br />"Furthermore, if a permanent pool is allowed for fish and wildlife as receJ!.tly proposed, <br />the trap efficiency will undoubtedly be greater than 96 per cent. II <br />It may therefore be concluded that a permanent pocl would cause a constant sediment re- <br />tention rate of at least 96 per cent, as OppOsed to the present condition which allows per- <br />iods during which sediment retention is as low as 13 per cent. <br />Inherent in these diverse rates of sedimentation is the effect on canal los$es and the <br />change in quality of irrigation water. Average transportation losses increase byapproxi_ <br />mately 10 per cent of total water diverted when clear Reservoi'l' water is run for any length <br />of time. Some areas below John Martin Reservoir experience periodic raising and lowering <br />of the groun4 water level. These fluctuations may be directly corollated to the percent- <br />age of sediment carried by irrigation water. The period from 1948 through 1951, during <br />which John Martin Reservoir was never empty, brought about a substantial raise in the <br />ground water level in some irrigated areas of Prower8 County. This condition necessitated <br />the construction of several drainage ditches to compensate for the increased water table. <br />The flow of these drains varies inversely with the sediment content of the irrigation wate~ <br />Irrigators welcome a periodic supply of water with high silt content. Many farmers <br />value mUddy water at one and ene-half times above the value of clear water. If one assumes <br /> <br />a value o~ $30.00 per acre foot for clear water <br />$45.00 per acre foot. These values are recognized <br />irrigators assume. <br />The ditches in COlorado below John Martin Resel'voir divert en annual average of <br />165.000 acre feet of river w~ter. A 10 per cent loss on this quantity, valued at $30.00 <br />per acre foot, would amount to $495.000.00. If it is assumed that'muddy water is worth <br />$15.00 per acre foot more than clear water, then the difference would be $2,475,.000,.00. <br />These figures would indicate a total annual loss to irr'igators, if it is necessary to Use <br />clear water as opposed to water of high ailt content, of $2,970,000.00. However, John <br />M&rtin Reservoir has hiHtorica]]y contained stored water about 45 per cent of the time dur- <br />ing the irl'igation season. The adjusted average annual less to irri.gators attributable to <br />a permanent pool woule. then beccme $1,633,500.00. <br /> <br />then the muddy water would be valued at <br />as being lOwer than tho~e which most <br /> <br />Quality of Irrigation Water <br /> <br />Plants in saline soils such as are common in the lower Arkansas Valley are adversely <br />affected by high concentrations of salts in the soil solution and by poor phySical condi_ <br />tion of the 30il. Both these soil conditions are affected by the quality of the irriga_ <br /> <br />-- Page :5 -_ <br />