Laserfiche WebLink
CRDSS Water Resources Planning Model (StateMod). In general, reservoirs with <br />greater than 4,000 acre-feet capacity were modeled explicitly in the CRDSS planning <br />model effort. The remaining smaller reservoirs were aggregated by water district to <br />account for permitted storage in each basin. StateMod predicts historical monthly <br />reservoir evaporation during the historical simulation for each basin, based on historical <br />use of the reservoir and representative evaporation rates for the reservoir locations. <br />Simulated reservoir end-of--month contents match historical end-of--month contents <br />reasonably well and yearly changes in reservoir contents match very well. Therefore, the <br />model is assumed to be an acceptable predictor of historical reservoir operations and <br />reservoir evaporation for use in this report. <br />The USBR typically assigns a percentage of the estimated evaporation from the upper <br />basin Colorado River Storage Project (CRSP) reservoirs each of the upper basin states in <br />the determination of each State's consumptive uses. The CRSP reservoirs include Blue <br />Mesa and Morrow Point Reservoirs, both located on the Gunnison River in Colorado, <br />Flaming Gorge Reservoir in Wyoming, and Lake Powell in Utah. This report presents <br />estimated Consumptive Uses and Losses associated with Colorado exclusive of the CRSP <br />evaporation. <br />Ground Water <br />Similar to the USBR Consumptive Uses and Losses reporting, ground water use has not <br />been taken into account in the computation of tributary consumptive use. An interagency <br />study team consisting of various State Engineers Offices, USBR, and other pertinent <br />agencies has been proposed to develop guidelines for predicting depletions due to <br />pumping on an area by area basis. Future reports should incorporate the results of this <br />study. <br />Stockpond Evaporation and Livestock <br />Stockpond evaporation is based on the results of the StateMod planning model historic <br />simulations. Storage capacities (tank capacities) for permitted stockponds were obtained <br />from State Engineer's Office records of non jurisdictional dams. Individual capacities <br />were aggregated into stockponds representing storage capacities by water district. Based <br />on the maximum capacities, estimated surface areas, and representative evaporation rates <br />for the Stockpond location, monthly evaporation was estimated. <br />Livestock counts were obtained, by county, from the state agricultural statistics. <br />Livestock consumptive use was estimated by multiplying the number of animals in each <br />county by the average use rate taken from the Midwest Plan Service Structures and <br />Environmental Handbook 1977. <br />Stockpond and livestock data are adequate to prepare an estimate of this use. <br />Considering the small amount of Stockpond and livestock water use, any refinement of <br />consumptive use estimates would be best spent on the irrigation or evaporation <br />culossapp Page 9 of 24 09/30/1999 <br />