Elephant Butte Dam or Elephant Butte Dike is a concrete gravity dam on the Rio Grande river near Truth or Consequences, New Mexico. The dam impounds Elephant Butte Reservoir, which is used mainly for agriculture, and also provides for recreation, hydroelectricity and flood control. The construction of the dam has reduced the flow of the Rio Grande to a small stream for most of the year, with water released only during the summer irrigation season, or during times of exceptionally heavy snow melt.HistoryThe dam is part of the Rio Grande Project, a project to provide power and irrigation to south-central New Mexico and west Texas. The United States Congress authorized construction of the dam on February 25, 1905 and it began in 1911. It was completed in 1916 but allowed to begin filling in 1915.At the time of its construction, the dam was the largest irrigation dam ever built with the exception of the Aswan Dam in Egypt. It was expected that the dam would become the property of the local settlers once a water tax had reimbursed the government for the cost of construction. During construction the government used a system of 3 cables, each having a capacity of 15 tons and a span of 1400ft.The name "Elephant Butte" refers to a volcanic core similar to Devils Tower in Wyoming. It is now an island in the lake. The butte was said to have the shape of an elephant.