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July through October. Snowmelt flooding is characterized by mod- erate peak flows, large vOlume, long duration, and marked diurnal fluctuation of flow. Snowmelt runoff may occasionally be augmented by rain. Rainfloods are characterized by high peak flows of mod- erate volume and duration. Flooding is more severe when antecedent rainfall has resulted in saturated ground conditions, or when the ground is frozen and infiltration is minimal. Convective type cloudburst storms, sometimes lasting for several hours, can be expected to occur in the Montrose region during the summer. Runoff from these storms is characterized by high peak discharge, short duration, and small volume. Due to the small areal extent of cloud- burst storms, they would have little effect in the study area un- less they occurred concurrently with rapid snowmelt or runoff from general rain. The earliest reference to a ~lood on the main Uncompahgre River came from the settlers who founded Delta, Colorado, in the early 1880s. At that time, an Indian squaw, Chipeta, wife of the famous Ute Chief Ouray, stated that within her lifetime of (then) approxi- mately 50 years, she had seen the Uncompahgre Valley at Delta "flooded from bluff to bluff" (Reference 5). Records show that, since the turn of the century, notable high flows occurred on the Uncompahgre River in 1921, 1927, 1938, 1941, 1944, 1947, 1957, 1973, and 1975. The largest known flood, esti- mated peak flow of 5,140 cubic feet per second (cfs) as recorded at the Colona stream gage (approximately 10 miles upstream of Montrose), occurred approximately mid-June 1921 as a result of snowmelt. Based on the results of this study, the 1921 flood is estimated to have been slightly larger than the 100-year frequency flood. The only notable cloudburst flood of record occurred in July 1923. Peak flows of the larger historical floods on the Uncompahgre River are shown in Table 1. Historical flooding in the Uncompahgre Valley, described in avail- able newS articles, has damaged or destroyed railroad track and embankments, road and railroad bridges, roads, diversion structures, and buildings and their contents. Inundation of agricultural pro- perty has eroded farmlands; damaged and destroyed crops and irriga- tion systems; reduced soil productivity as the result of salinity; and deposited sand, silt, and debris on cropland and pasture. Rail- road and highway traffic has been disrupted, public utilities damaged and destroyed, homes evacuated for as long as several days, and cattle moved to higher ground to protect them from the possibility of drowning. According to newspaper articles from the Montrose Daily Press (men- tioned in References 2 and 3), notable floods occurred in the Mon- trose area in 1938, 1964, and 1967. This area includes the Cedar 6