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<br />00lH3 <br /> <br />6 <br /> <br />depletions above the Little Snake provided by the Division 6 office of the State Engineer, there has been <br />a slight upward trend in depletions with Craig Unit III and Stagecoach Reservoir since 1985. <br /> <br />These effect of these assumptions is to somewhat overstate depletions and to predict baseline <br />flows which are relatively lower, According to the USFWS, this was largely intentional in order to define <br />a worst-case scenario to evaluate flows for fish. <br /> <br />Comparison of Environmental Baseline and Task 2 Depletions <br /> <br />Existing Depletions <br /> <br />The most important thing to keep in mind when comparing the existing Environmental Baseline <br />depletions with the existing depletions developed in Task 2 is the fact that the existing depletions <br />estimated in Task 2 are those actually observed in 1989, a dry year showing relatively high water <br />consumption, while the existing Environmental Baseline depletions described above are averaged ov~r a <br />period of 53' wet and dry years ending in 1982. To be strictly comparable, averages should be used in <br />both cases and both averaged periods should be identical ending with the same year. However, such a <br />strict comparison is not possible. . <br /> <br />Based on data from Division 6, the average irrigation depletion for the 1981-1989 period in the <br />Yampa River basin was about 60,300 AF/yr, This can be compared to an average of 55,600 AF/yr that <br />remains in the existing Environmental Baseline depletions after removal of the 19,900 AF/yr thermal. <br />electric adjustment. The actual I'layden and Craig depletions in 1989 are estimated to have been about <br />18,200AF; if this value is used rather than the 19,900 AI' estimate, the remaining Environmental Baseline <br />depletion is 57,300 AF/yr. <br /> <br />Between 1982 and 1989, additional sources of depletion became active. most notably those <br />associated with Yamcolo, Stagecoach, Lake Catamount, Steamboat Lake, and Elkhead reservoirs, These <br />depletions are all considered "future" in the Environmental Baseline but, with the exception of some <br />municipal and industrial deliver.ies, were "existing" as 'of 1989. If the municipal and industrial deliveries <br />are excluded, the growth in depletions between 1982 and 1989 attributable to these reservoirs can be <br />estimated at roughly 4,000 AI' /yr. <br /> <br />With these factors in mind, it appears that there is quite good agreement between the existing <br />depletions in the Environmental Baseline and those estimated in Task 2. <br /> <br />Future Depletions <br /> <br />One thing to keep in mind when comparing future depletions in the Environmental Baseline <br />with those estimated in Task 2 is the fact that the Environmental Baseline considers "future" as beginning <br />in 1983' while the Task 2 projections consider "future" to begin in 1990. Some "future" Environmental <br />Baseline depletions are now "existing" depletions, namely, evaporation from Yamcolo, Stagecoach. <br />Steamboat Lake, and Elkhead reservoirs and irrigation depletions supported by Yamcolo Reservoir. As <br />discussed above, these depletions total about 4.000 AF/yr. Removing these now-existing depletions <br />from consideration permits a more direct comparison of projected growth of depletions between the <br />Environmental Baseline and the result of Task 2, ' <br /> <br />" ;I <br />