WSP09117 - Laserfiche WebLink

Home Browse Search

OOU21l 40 TABLE V-I Pan Evaporation Data In the Arkansas River Basin In inches/ month from the U. S. Weather Bureau May June July Au~ust September Sugar loaf 6.28 6.47 5.74 5.01 4.31 Pueblo City Reservoir 9.09 10.46 10.85 9.07 7.52 Weighted Average 8.15 9.13 9.14 7.72 6.45 (1/3 Sugar loaf 2/3 Pueb I 0) After the average evaporation rate. was established for each of the ir- rigation months, the surface area of the river betweeh Twin lakes and the Colorado Canal was determined for "index flows" at Ca~on City from 200 to 2,000 cfs. The incremental area change due to a reservoir run (based on flow at Canon City before and du.rlng a run) could then be multiplied by the evap- oration rates to determine what incremental charge should be made against the reservoir rUn. The results of this analysis are shown in Figure V- 2. Figure V-2 can be used for administrative purposes for charging incre- mental evaporation loss to reservoir runS from any of the three upper Arkansas Reservoirs to Pueblo, the Bessemer, Excelsior and to the Colorado Canal. UNAUTHORIZED SURFACE DIVERSIONS Unauthorized diversions are an Important factor in the operation of the Arkansas River. They exist and will continue to exist even under the strqct- est administrative procedures that might be applied to controlling the river. It is humanly impossible to administer every we.ll and adjust every headgate, day and night, along miles of river to conform to the ever changing physical supply that Is avai lable for "appropriation." By increasing the number of Commissioners and their deputies, and by tightening the administrative rules, the Illegal diversions can bekept to a minimum, but never entirely eliminated. During a reservoir run the illegal diversions increase, particularly during the first part of the run when the stage of the river rises, thus putting a higher head on most of the headgstes and increasIng the various rates of diversions along the river. The reverse is also true when the reservoir re- lease is shut off. Cases have been reported where a ditch could legally take water, but the stage of the river was too low for It to divert any water due to an inadequate diversion structure (or no structure at all). Then when the stage of the river was increased, due to a reservoir run, the ditch was able to, and did, take all the water.it could. .This caused problems for ditches that were trying to identify and divert "the! r" reservoi r water. Some unauthorized diversions can be attributed directly to a reservoir run due to a rIse In the stage of the river. Some Illegal diversions are con- tinuously being made, whether there is a reservoir release or not. It is a legal and/or administrative decision how this latter category of river losses