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. . . The entire Republican River basin in Colorado extends southwest into Lincoln and Elbert Counties and east into Sedgwick, Phillips, Yuma, Kit Carson and Cheyenne Counties. The watershed then continues east into Kansas. The Southwest Drainage and Northern Drainage watersheds, which form a very small part of the Republican River basin, are entirely within Washington County, in the immediate vicinity of Otis. While climatic data for the Town of Otis is not available, such data is available for Akron and Yuma through the Colorado Climate Center. Average monthly summaries of precipitation, snowfall, and temperatures for both cities are included in Appendix I. There are some differences between the climatic information for the two communities, but basically Akron and Yuma provide a good representation of the climate in Otis_ Floodinl! Problems and Floodinl! Historv Flooding in Otis generally occurs during the spring and summer months as a result of flooding from thunderstorms and general rainstorms. Snowmelt flooding has not been a significant problem in Otis. Rainfall flooding in Otis is characterized by high peak flows with small volumes of water over a short duration. Because of the very flat terrain and the hydraulic obstructions that impede flow in Otis, these "small water volume" floods can actually take a long time to flow out of town. Otis has experienced flooding and storm drainage problems in both the north side and the south side of town. Some of those problems have been addressed through structural projects. Currently the majority of the south side of Otis is shown in the approximate IOO-year floodplain of the Southwest Drainage. The primary reason the floodplain is so large is the flow restriction posed by the two railroad culverts under the Burlington Northern Railroad. The culverts are too small to convey even a IO-year flood without causing ponding upstream. The 1986 hydraulic analysis by Engineering Professionals, Inc. concluded that during a IOO-year flood, floodwater would pond essentially to the top of the railroad embankment, resulting in flood depths on the south side as great as 6 or 7 feet. As described below, there has been flood control work conducted in Otis along portions of the Southwest Drainage to address as much of this problem as is economically feasible. The Northern Drainage is located approximately y,. mile north of the northern corporate limit of Otis. However, the IOO-year floodplain of the Northern Drainage extends south into Otis. When flood control work was completed along the Southwest Drainage, some improvements were also constructed along portions of the Northern Drainage. Otis' history includes several flood caused by heavy rains. Most recently, during the summer of 1993, the Southwest Drainage flooded. While the Midwest, including the mainstem of the Mississippi River, was experiencing record floO<ling in 1993, Otis and the surrounding area were at the western extreme of that summer's wet weather systems. Because of the constriction at the railroad crossing, the heavy rain resulted in floodwater in the Southwest Drainage ponding on the south side of Otis. It took approximately 36 hours for the majority of the ponded water to flow out of town. Longtime residents stated that there have been previous floods that were even bigger than 3