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Blue Mesa Reservoir, furthest upstream, i 9 the major ~t- nr:lf\('" feature of the unit (Reference 6). Taylor Park, Blue Mesa, Morrow Point, Crystal, and Paonia Reservoirs contribute to the reduct ion of 100- and 500-year flows along the Gunnison River. The Dallas Creek Project, located approximately 32 miles upstream of Olathe at Ridgeway, Colorado, in Montrose County, was completed in 1987, and filling was completed in 1990. Ridgeway Reservoir has 80,000 acre-feet of storage, with additional incidental flood- control storage for spring runoff of 26,000 acre-feet. A 1973 u.s. Army Corps of Engineers report states that this project will reduce the standard project flood of 7,000 cfs to a flow of 3,700 cfs at the damsite (Reference 7). Operation of the reservoir for conservation and storage based on snowmelt forecasts could provide incidental flood-control benefits to downstream floodplain areas along the Uncompahgre River. However, no benefit has been assumed in this restudy. Improvements such as dikes and bank protection have been made at various locations along the Uncompahgre River. The dikes along the Uncompahgre River are minor structures around abutments and have no effect on the 100- and SOO-year floods. Significant flood protection from the 100- and SOO-year floods is provided by several irrigation canals that branch off from the river at different locations upstream of the study area. These canals are part of the Uncompahgre Project, which was completed in 1931. This project included many diversion dams and canals, as well as the Gunnison Tunnel and the Taylor Park Dam (Reference 8). Several of the irrigation ditches cross the Gunnison and Uncompahgre River basins, notably the South Canal (fed by the Gunnison Tunnel from the Gunnison River) and the Loutsenhizer Canal (which draws from the Uncompahgre River). The South Canal typically carries 900-1000 cfs of flow, while the Loutsenhizer Canal conveys approximately 200 efs. Other irrigation canals that branch off from the Uncompahgre River include East Canal, Montrose and Delta Canal, and West Canal, upstream of the study area, in Montrose County. Concurrent with periods of snowmelt runoff, maximum allowable flow (all gates open) is usually in effect for the irrigation canals in order to meet the requirements of agricultural areas. During periods of excessively high flows on Uncompahgre River, transbasin diversions from the Gunnison River to the Uncompahgre River valley are reduced to alleviate flood conditions. 3.0 ENGINEERING METHODS For the flooding sources studied by detailed methods in the communi ty, standard hydrologic a.nd hydraulic study methods were used to determine the flood hazard data required for this study. Flood events of a magnitude which are expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or SOO-year period (recurrence 8