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On the Roaring Fork River, the largest discharge recorded was in July 1957 with a peak of 19,000 cubic feet per second (cfs). A U.S. Army Corps of Engineers (US ACE) letter report (Reference 12) described the 1957 flood as follows: Floods on the Roaring Fork result from snowmelt and occur principally during the month of June. The flood of July 1, 1957, had an instantaneous peak discharge of 18,700 cfs at the Glenwood Springs gage. This flood was the maximum of 49 years of record, and its magnitude has an estimated frequency of occurrence of once in approximately 60 years. The river in the problem area is characterized by low banks, braided channels, and a considerable amount of gravel, cobbles, and snags deposited on gravel bars. The river carries a large bedload of gravel and cobbles, some of the latter being more than 6 inches in diameter. The capacity of the channel has been reduced by this sediment. In some instances, where channel changes took place during the flood, the original channels were so filled with sediment that nearly all of the present flows are discharging through the new channels. Generally, however, the new channels are old watercourses abandoned by the river in previous years. The littered condition of the channels, and the increased danger of bank erosion, inundation, and resultant channel changes constitute the present flood problem. The principal items damaged caused by the 1957 flood were the agricultural lands and roads and bridges adjacent to, or over the river. A few farm buildings were flooded. The total known damages in all categories along this reach amounted to slightly more than $45,000. A common type of damage from the 1957 flood was bank erosion. The slope of the stream ranges from 65 feet per mile above Basalt to 40 feet per mile below Basalt. Velocities probably in excess of 10 feet per second occurred during the 1957 flood. The banks are composed largely of sand, gravel, and cobbles overlain by a comparatively thin mantle of soil, and are quite erosible. Spoil-type dikes, constructed by local interests with material bulldozed in the process of channel clearing, proved to be very erosible. A substantial percentage of the total damages were due to overtopping of the low banks and the inundation of pasture and croplands. The banks in most instances range from only 2 feet to 5 feet in height. In two locations, where old channel areas have been reclaimed, considerable volumes of overflow and widespread flooding resulted from bank overtopping at the upper ends of the areas. More than one-half of the known damages in the 1957 flood were caused to roads and bridges in the area, with nearly $24,000 of damages being caused to 3 bridges and their abutments. Two of these were public bridges that have since been restored. A third bridge, which was private, was completely destroyed and has not been replaced. On the Roaring Fork River Basin, precipitation varies widely above the Town of Basalt. On the Continental Divide, near Independence Pass, the- average annual precipitation is 13