Conchas Dam is a dam on the Canadian River in San Miguel County, New Mexico in the United States, about 50 mi northeast of Santa Rosa. Forming Conchas Lake, it is a concrete gravity dam flanked by earthen wing dikes, standing 235 ft high with a total length of 19500 ft. The dam serves mainly for irrigation water supply and flood control and is operated by the U.S. Army Corps of Engineers. First proposed in the early 1930s, the dam was initially rejected because of its remote site and Depression conditions in New Mexico. However, the dam was made a possibility in 1935 with the passage of the Emergency Relief Appropriation Act, which authorized several public works projects in New Mexico to provide relief to unemployment. Initial site work began in 1935 with construction on the actual dam starting in 1936. In 1939 construction was completed at a cost of $15.8 million. Conchas Dam holds back a permanent pool of 61532 acre feet, with a maximum flood-control capacity of 709119 acre feet. At normal water levels the reservoir has a surface area of 2694 acre, increasing to 16033 acre at full pool. The dam and reservoir are the primary feature of the Tucumcari Irrigation Project. Water released from the dam is diverted into 300 mi of canals which irrigate 41400 acre of land in the Canadian River valley. The irrigation works were built by the U.S. Bureau of Reclamation from 1940–1942 and were turned over to the Arch Hurley Conservancy District in 1954.