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Colorado's Depletion Plan envisions replacing the seasonal (e.g., May-June) depletions with <br />re-regulated accretions (arrows on above graph). To the extent that net accretions exceed the <br />volume needed to fill the seasonal depletive "hole" that is created, they also increase the <br />average annual streamflow at Julesburg. <br />U.S. Fish & Wildlife Service has conceptualized two "reasonable first increment scenarios" <br />of water supply development to serve population growth in Colorado's South Platte basin. <br />Both scenarios assume a population growth of 1,100,000 (1997 through 2020), with a <br />distribution of 32%/ 45%/ 23% in the North, Central, and South regions respectively. The <br />scenarios differ only in the assumed proportion of water supply sources: <br />Scenario 1 (Based on Tab3B "initial assumptions") <br /> North Central South <br />Trans-basin imports 40% 30% 20% <br />Non-tributary water 0% 10% 50% <br />Agricultural conversion 35% 5% 0% <br />Conservation 5% 15% 10% <br />Water re-use 10% 25% 10% <br />Native S. Platte development 10% 15% 10% <br />TOTAL 100% 100% 100% <br />Scenario 2 (Limited by Tab3B's "assumed maximum seasonal depletion" of 1,800 acre- <br />feet per 100,000 population. Shaded blocks were adjusted by FWS to reach <br />this limit.) <br /> North Central South <br />Trans-basin imports 27% 18% 10% <br />Non-tributary water 0% 10% 50% <br />Agricultural conversion 35% 5% 0% <br />Conservation 5% 15% 10% <br />Water re-use 15% 30% 15% <br />Native S. Platte develo ment 18% 22% 15% <br />TOTAL 100% 100% 100% <br />Scenario 1 results in 297,000 acre-feet of new water supply required in the "average <br />hydrologic year", with 86,000 acre-feet (29%) provided by the two sources potentially having <br />a negative effect on peak flows (water re-use and native South Platte development). <br />Scenario 2 results in 121,000 acre-feet (44%) provided by these two sources in the "average <br />hydrologic year". <br />These figures compare to the more than 350,000 acre-feet provided by these sources as <br />assumed in Hydrosphere's initial analysis (July 21, 2003).