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2.2 Community Description Fremont County is located in south-central Colorado in the foothills of the Rocky Mountains, 45 minutes southwest of the City of Colorado Springs and 39 miles west of the City of Pueblo. The county is bordered by Teller and Park Counties to the north, Chaffee County to the west, Saguache, Custer, and Pueblo Counties to the south, and Pueblo and EI Paso Counties to the east. The Town of Brookside, City of Canon City, Town of Coal Creek, City of Florence, Town of Rockville, and Town of Williamsburg are all incorporated communities located within Fremont County. The City of Canon City is the county seat. U.S. Highway 50 runs through the center of the county. One of the longest rivers in the U.S., the Arkansas River, rises in the central Colorado Rockies near Leadville, Colorado, and empties into the Mississippi River southeast of Pine Bluff, Arkansas. The Arkansas River Basin above Fremont County is characterized by high mountain valleys surrounded on three sides by mountains reaching altitudes of more than 14,000 feet. The basin is surrounded by mountain ranges that act as orographic barriers to major storm systems. Downstream of Canon City, this valley opens up into a wide river valley with less orographic barriers (Reference 3). The climate is relatively mild; the average winter high temperature is 540F and the low is 290F; the average summer high temperature is 770F and the low is 50F. The average rainfall is approximately 14 inches, while average snowfall is approximately 15 inches (Reference 3). The U.S. Census reported the population of Fremont County has increased from 20,196 in 1960 to 46,145 in 2000 (Reference 4). 2.3 Principal Flood Problems The Arkansas River above Canon City is a typical mountain stream which descends 6,000 vertical feet in a distance of less than 130 miles, at gradients often exceeding 50 feet per mile. While slopes are steeper in the upper drainage basins the dense vegetation in these areas serves to reduce rainfall runoff. A greater percent of runoff is permitted by the sparse vegetation of the foothills and pasture land at the lower elevations. Consequently, the majority of floods in the study area are usually caused by general rainstorms and cloudburst storms occurring from May through September. During this period, warm, moist air masses from the Gulf of Mexico combine with cold and comparatively dry air from the polar regions to cause thunderstorms. Floods resulting from prolonged heavy rainfall over the watershed are characterized by moderate volume and duration. The cloudburst type is a high-intensity, short-duration rainstorm which produces a flood of high peak flow, short duration, and small volume of runoff. Flood potential also exists from rapid melting of heavy snow cover in late spring and summer. Flood flows resulting from snowmelt are characterized by moderate peaks, large volume, and long duration. Arkansas River peak flow from snowmelt occurs in June and July. This peak flow in combination with rainfall can cause severe flooding. 5