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. '.'1' '^} k" t Associated funct~,~ Pueblo Reservoir includes 93,000 acre-feet of flood control storage which would significantly reduce potential flood damages along the Arkansas River between the Pueblo and John Martin Reservoirs. Historical records show that from Canon City eastward damaging floods along the Arkansas River are fairly frequent and of sizable volume and mgnitude. The largest flood of record, caused by intense rains in the vicinity of Pueblo, occurred in June 1921. This flood reached a peak disCharge of about 103,000 second..feet at Pueblo. Downstream tributaries contributed to the flow until the peak reached about 200,000 second-feet at La Junta. The John Martin Reservoir provides flood protection to downstream areas. The reach of the river above that reservoir has no protective works other than the floodway channel through the city of Pueblo. The Corps of Engineers conducted the flood control studies during the original project investigations. The Corps has reevaluated the flood control benefits attributable to the project at $708,000 annually. Detailed evaluations for fish and wildlife and recreation have not been made in the eastern slope areas of the Fryingpan- Arkansas Project. During the original project stUdies, however, the Fish and Wildlife Service and the Colorado Department of Game and Fish collaborated in studies on the western slope water collection area. They concluded that costs of the Hunter Creek Extension Diversion Dam and Canal and some incremental capacities in the South Side Collection System and the Fryingpan-Arkansas Divide Tunnel were justified for inclusion in the plan. Those increments would prevent future fishery losses that would occur on the upper reaches of the Roaring Fork River when the Twin Lakes Reservoir and Canal Company diverted water up to its full right. The extensions and increased capacity of these features would permit up to 3,000 acre.feet of surplus flows in May and June to be diverted via project facilities for storage in east slope reservoirs. The 3,000 acre-feet would be released to the Twin Lakes Company in the late summer months in lieu of diversions through the Twin Lakes Tunnel, thus preserving adequate flows for fish in the Roaring Fork River. The original evaluation of sediment control benefits of $141,000 ann!l8.11y from the Pueblo Reservoir has been retained for this analysis. These benefits consist of prolongation of the useful life of the John Martin Reservoir and anticipated reduction of annual operation and maintenance expenses at existing diversion works and canals between the two reservoirs. 18