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U.S. Army Corps of Engineers (References 3 and 4). In the U.S. Army Corps of Engineers study, the flood discharges were computed by use of the HEC-l rainfall-runoff computer model (Reference 5) and a detailed statistical analysis of stream gage snowmelt data in the study area. A drainage area-peak discharge relatlonship was dclclminC'd rOt the upstream segment of Fortification Creek, north of the City of Craig, based on discharges determined for the lower portion of Fortification Creek by the U.S. Army Corps of Engineers (Refer- ences 3 and 4). Peak discharges were calculated by computing cubic feet per second per square mile values for the downstream segment of Fortification Creek and applying the values using a drainage area-peak discharge relationship for the reach upstream of Craig. For Fortification Creek and Cedar Mountain Gulch, the reductions in the 100- and 500-year discharges throughout the City of Craig are due to sheet-flaw diversions from the channel. Peak discharges for Sand Gulch and Sand Gulch Tributary were computed by constructing a drainage area-peak discharge curve for flooding sources in the Craig area with relatively the same size drainage areas. The streams used to construct the curve were Pine Ridge, Cedar Mountain, and Brotherton Gulches. Peak discharges for Lay Creek and Big Gulch were computed using the procedures outlined in the Craig, Colorado, Flood Hazard Informa- tion report prepared by the U.S. Army Corps of Engineers (Refer- ence 3). The study consists of a detailed probability analysi5 of stream gage (snowmelt) data in conjunction with the HEC-l rainfall- runoff model (Reference 5). For the HEC-l rainfall-runoff model for Lay Creek and Big Gulch, the precipitation values were obtained from Precipitation-Frequency Atlas of the Western United States (Reference 6). The unit hydrographs used in the computations were computed using the General Mountain S curve. Loss rates used in the HEC-l model were computed using U.S. Soil Conservation Service Curve numbers (Reference 2). For Lay Creek and Big Gulch, the flood discharges computed in this study are much lower than the flood discharges computed for the Craig area. Examination of basin characteristics reveals that the lower values in the Lay areas are caused by different precipita- tion patterns (design storms) and much lower average basin slopes. The different precipitation patterns are caused by aerial adjustments to the design cloudburst storms to spread them over entire basins. The basins in the Craig area are much smaller and are covered by entire cloudburst storms. Examination of basin slopes show the slopes in the Craig area are generally much steeper, on the order of 3 to 6 times higher. 11