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TABLE V MINIMUM FLOWS AT THE MOUTH OF THE LARAMIE SPECIFIED IN THE GRAYROCKS AGREEMENT October-March April May-September 40 ft3/s (about 2400 acre-ft/month) 50 ft3/s (about 3000 acre-ft/month) 40 ft3/s or 75% of natural flow, whichever is greater Subject to the following qualifications: 1. MBPP will not be required to release more than 200 ft3/s or 12 000 acre- ft during any month. 2. Whenever the reservoir level drops below 50 000 acre-ft,the minimum flows are as fo llows: October-March April-September 20 ft3/s 40 ft3/s 3. If the Corn Creek project is flows less 22 500 acre-ft/yr, Platte 11 250 acre-ft/yr. built, MBPP will deliver into the Laramie the and will in addition deliver into the North In any given year, deviations from this average might occur because of changes in the reservoir level. As part of its original agreement with MBPP, the Corn Creek Irrigation Project was entitled to 22 500 acre-ft. Thus, if Corn Creek were to be developed, return flow (assumed to be 7500 acre-ft/yr) would be delivered into the North Platte each year regardless of natural flow. In those years when the natural flow of the Laramie was insufficient to meet the combined needs of MBPP and Corn Creek, the difference would be made up by reservoir drawdown. This means that in dry years, the net depletions will be less than 38 000 acre-ft/yr. On the other hand, depletions will be greater than this average whenever the water not needed by MBPP and Cave Creek is used for filling the reservoir. Occasionally, the depletion will be quite large such as in the first year fol- lowing a drought. In our simulation, the cumulative deficit over the 2 years (I957 andJ958) was 137 000 acre-ft. Thus, for downstream users, the reservoir would have prolonged the drought of the 1950s for an additional 2 years, at least so far as the Laramie was concerned. In those years, a depletion of this magnitude on the Laramie would have reduced the flow of the Platte at Overton, Nebraska, by nearly 6%. 49