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precipitation occurs in the form of snow with deep snowpack developing in the higher elevations. Therefore, in the spring and early summer, runoff from melting snow presents a moderate and constant flood threat, but high peak flows are not characteristic of snowmelt runoff. Cloudburst storms constitute a severe flood threat along Lost Canyon Creek as high-intensity rainfall is produced, but due to the small areal extent, small volume of runoff, and short duration of this type of storm, a significant flood threat is present only in the smaller drainage basins. Overall, however, frontal type rainstorms present the most serious flood hazard in the area studied. History proves this fact; in October 1911, the largest flood of record resulted from this type of storm on the drainage ar~as of the Dolores and West Dolores Rivers, flooding much of the Town of Dolores. Heavy rain along Lost Canyon Creek in October 1941 caused flooding in that area. In May 1941 and June 1949, large snowmelt flows occurred on the Dolores River. The most r~cent flooding occurred in September 1970, but the magnitude of flow of that flood was not recorded. Historical records of flooding events on the Dolores River are primarily based on newspaper accounts, with indications that high water-surface elevations occurred in 1909, 1911, 1932, 1937, 1938, 1941, 1944, 1949, 1957, and 1970 (References 1 and 3). Flood loss in the study area usually consists of limited damage to bridges and irrigation structures. 2.4 Flood Protection Measures In 1985 the U.S. Bureau of Reclamation completed construction of the Dolores landfill and protective dike. This project, which was built in conjunction with the Bureauts construction of the McPhee Dam, involved construction of 2,100 feet of levee and landfill between the State Route 145 embankment and the Fourth Street Bridge, along the right bank of the Dolores River. In addition, the project included the rehabilitation of two segments of existing levee along the right bank of the Dolores River upstream of the Fourth Street Bridge. These levees were constucted to prevent flooding resulting from the maximum pool elevation of the McPhee Reservoir. The levees upstream of Fourth Street do not have sufficient freeboard to be recognized as providing protection from 100-year overbank flooding. The landfill and levee upstream of State Route 145 were considered ~n this study regarding their effect on overbank flooding. 3.0 ENGINEERING METHODS For the flooding sources studied by detailed methods in the community, standard hydrologic and hydraulic study methods were used to determine the flood hazard data required for this Flood Insurance Study. Flood events of a magnitude which are expected to be equaled or exceeded 4