The Mancos Project

Settlement and irrigation of the Mancos Valley began about 1876. The natural flow of the Mancos River during the months of July, August, and September is very low, and the irrigation water supply for those months inadequate. By 1893, when a state adjudication of water was made, late summer demands for irrigation water far exceeded the supply. To alleviate the shortage, three small reservoirs storing approximately 1,500 acre-feet of water were built by local irrigation organizations. In 1937, U.S. Bureau of Reclamation investigations led to the conclusion that the Jackson Gulch Reservoir site, an offstream storage basin, was the only site of sufficient size to furnish an adequate project water supply. At that time, the project did not appear economically feasible, but it received further consideration under the Water Conservation and Utilization Act of 1939. It was formally approved nearly 75 years ago on October 21, 1940. The Mancos Project in the southwest corner of Colorado consists of the Jackson Gulch Dam and Reservoir, the inlet canal, and the outlet canal. Project lands extend downstream about 10 miles and can furnish a supplemental water supply to 13,746 acres.