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The precipitation intensity rises with increased elevation, as does the velocity of runoff and sediment production. Snowmelt flooding is negligible on Indian Wash. Information from local residents indicates that before construction of the U.S. Soil Conservation Service IW-l flood retention structure, damaging floods occurred on an average of every 6 years. Precipita- tion records indicate that large storms occurred in September 1896, May 1906, October 1908, August 1921, August 1938, September 1941, June 1954, May 1955, and June 1958. The 1908 storm produced the largest 24-hour total precipitation of 2.50 inches. The 1938, 1954, 1955, and 1959 storms were storms over the upper portion of the watershed with little precipitation being recorded in Grand Junction. The 1958 flood is the only flood with documentation on flood heights and damages. The storm caused sediment and water damage to residences, business establishments, and streets. The total damages were estimated at $25,000. Considerable overland flow resulted, but depths were not excessive (Reference 3). The 1958 flood has been estimated to be greater than the 100-year flood. Figures 3 and 4 show photographs taken during and after the June 6, 1958, flood. 2.4 Flood Protection Measures Levees along the south bank of Colorado River downstream from the mouth of Gunnison River were constructed by local interests to protect residents in the Connecticut Lakes area. Low dikes were also constructed along the north bank of Colorado River upstream from the Grand Avenue bridge to provide protection to residents of the Riverside Park area. Both the levees and the dikes are overtopped by the 100- and 500-year floods. Major reservoirs controlling Colorado and Gunnison Rivers above Grand Junction are Granby, Green Mountain, Dillon, Williams Fork, Reudi, Taylor Park, Vega, paonia, Morrow Point, and Blue Mesa. The reservoir storage capabilities are shown in Table 1. The Granby, Green Mountain, Dillon, Williams Fork, and Reudi Reser- voirs are fill and spill type structures with only incidental flood control storage. In the Gunnison River drainage basin, regulations for joint conser- vation-flood control operation of Paonia Reservoir have been prepared by the U.S. Army Corps of Engineers and the U.S. Bureau of Reclama- tion. The conservation operation of Blue Mesa Reservoir provides substantial flood control benefits, but formal operating regulations for flood control have not been prepared. 8