Conchas Dam is a dam on the Canadian River in San Miguel County, New Mexico in the United States, about 50 miles northeast of Santa Rosa. Forming Conchas Lake, it is a concrete gravity dam flanked by earthen wing dikes, standing 235 feet high with a total length of 19,500 feet. The dam serves mainly for irrigation water supply and flood control and is …Conchas Dam is a dam on the Canadian River in San Miguel County, New Mexico in the United States, about 50 miles northeast of Santa Rosa. Forming Conchas Lake, it is a concrete gravity dam flanked by earthen wing dikes, standing 235 feet high with a total length of 19,500 feet. The dam serves mainly for irrigation water supply and flood control and is operated by the U.S. Army Corps of Engineers.