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Inflow to Blue Mesa was routed under the assumption that the respr- uld be at minimum ower pool level present operation (200,000 c prior to tg@ main 30 nAY~ nf flow Tt was found that this prior 60-day inflow could be routed thlollgh the reservoir and drawn back down to 200,000 acre-feet again by June 1, the start of the maximum 30-day inflow. Releases were made so as not to exceed channel capacities whenever possible (17,000 cfs on Gunnison River at Grand Junction and 48,000 cfs on Colorado River below Grand Junction). Water is diverted from numerous sites in the upper portions of the Colorado River basin for exportation to the basins of South Platte and Arkansas Rivers. However, diversions are commonly decreased during high runoff periods making any reduction in flood peaks unlikely. Irrigation uses also reduce flows, but not signifi- cantly, during times of peak flows. Various Federal agencies have been studying the water resources development aspects of the upper Colorado River basin for many years. A report published in 1971 (Reference 4) contains a reconnaissance plan that identifies, for future detailed study, eight potential storage projects that would provide flood control benefits for Mesa County and three areas for possible future watershed treatment measures. A publica- tion of the Colorado Water Conservation Board and the U.S. Depart- ment of Agriculture (Reference 5) includes information from a reconnaissance study that identifies a number of Roan and Book Cliffs streams that are potentially subject to development of storage projects for flood control. Since the devastating 1958 flood, a number of flood protection improvements have been made on Indian Wash. The primary flood protection measure is the U.S. Soil Conservation Service IW-l retention structure. The structure, shown in Figure 5, is located northeast of the airport and was completed in the early 1960s. The structure drains an area of 6.2 square miles and was designed for a total storage capacity of 2140 acre-feet including 570 acre- feet of sediment storage. Recent measurements .indicate. t,hat s.edi- ment accumulation has accounted for approximately 20 acre-feet since completion of the structure. This value is much less than anticipated because a number of small upstream reservoirs, which do not provide flood protection, do trap sediment. It is estimated that the structure will provide protection for the 6.2 square miles of watershed for floods greater than the 100-year frequency event (Reference 6). Other flood protection measures include Goverrunent Highline Canal and a 1979 channelization project on Indian Wash from North Avenue to Texas Avenue along 28th Street. Goverrunent Highline Canal, as discussed in the U.S. Soil Conserva- tion Service Indian Wash Watershed Work Plan (Reference 6), has a high spoil bank and roadway along the south side. Therefore, 11