Elephant Butte ReservoirReservoir on the Rio Grande, just north of Truth or Consequences and created by the Elephant Butte Dam constructed 1911-1916. While the actual volume is variable depending upon runoff and provision, the Reservoir can hold over 2 million acre feet and is the largest reservoir in New Mexico, providing irrigation to 170,000 acres. The Reservoir gains its name from an elephant-shaped butte in the flooded valley, now an island. Elephant Butte State Park encompasses the reservoir, and permits fishing and water sports.