Rio Grande Dam is a dam in Hinsdale County, Colorado impounding the Rio Grande. Built between 1910 and 1914 by the San Luis Valley Irrigation District to store water for agriculture in the San Luis Valley, Rio Grande Dam is an earth and rock fill dam 111 ft (34 m) high and 550 ft (170 m) long. The dam impounds the Rio Grande Reservoir, with a capacity of 52,000 acre⋅ft (64,000,000 m3).