Water Supply Definitions

Native Rio Grande Water: Water that is generated within the Rio Grande Basin and is subject to the rules of the Rio Grande Compact.

San Juan-Chama Water: Water that is imported from the San Juan River Basin as part of the Bureau of Reclamation’s San Juan-Chama Project. This water is not subject to the rules of the Rio Grande Compact.

Rio Grande Compact: A water-sharing agreement that apportions Native Rio Grande water among the states of Colorado, New Mexico, and Texas.

Article VI: A provision in the Rio Grande Compact that requires New Mexico to store a volume of water equal to its delivery debt at Elephant Butte, when requested by Texas, before additional water can be stored for use in New Mexico.

Example: If New Mexico’s Rio Grande Compact debt is 121,500 acre-feet, New Mexico must first store and hold 121,500 acre-feet for Texas in its upstream reservoirs. This water remains stored until Texas requests its release. Only then can New Mexico store additional water for use in the middle Rio Grande.

Article VII: A provision in the Rio Grande Compact that prohibits New Mexico from storing water in its reservoirs upstream of Elephant Butte when total storage in Elephant Butte and Caballo Reservoirs is less than 400,000 acre-feet.

Example: As of December 17, 2024, the combined storage in Elephant Butte and Caballo was 185,000 acre-feet—well below the 400,000 acre-feet threshold.

Otowi Index Gage: A USGS river gage on the Rio Grande upstream of Cochiti Reservoir. Under the Rio Grande Compact, New Mexico is required to deliver a specific percentage of Native Rio Grande flows, as measured at this gage, to Elephant Butte.