Rio Grande River Basin

The Colorado portion of the Rio Grande Basin, located in south central Colorado, encompasses approximately 7,543 square miles (7.2 percent of the state’s area). The San Luis Valley is a primary feature of the basin, extending from the foothills of the San Juan Mountains east toward the Sangre de Cristo range. Major tributaries include Alamosa River and Conejos River. 

Quick Facts
Description Value (approximate)
Irrigated Acres (2010) 1 512,000
Decreed Points of Diversion 1 3,000
Decreed Wells 1 14,180
Major Reservoirs 2
  • Sanchez Reservoir
  • Platoro Reservoir
  • Rio Grande Reservoir
Normal Storage (acre-feet)
  • 103,114
  • 59,571
  • 52,192
Major Imports into Basin 2
  • Weminuche Pass Ditch
  • Tabor Pass Ditch
  • Pine River-Weminuche Pass Ditch
Average Diversions (acre-feet) (1971-2003)
  • 1,133
  • 827
  • 426
Major Exports from Basin 2
  • Medano Ditch
  • Hudson Branch Ditch
Average Annual Diversion (acre-feet)
  • 843
  • 157

1 Source: CDSS, total values derived from GIS Data for Rio Grande Basin
2 Source: Statewide Water Supply Initiative Fact Sheet for Rio Grande Basin, CWCB, 2006


Compact Facts
  • Rio Grande Compact of 1938:  The Rio Grande Compact establishes Colorado’s obligation to ensure deliveries of water at the New Mexico state line and New Mexico’s obligation to assure deliveries of water at the Elephant Butte Reservoir, with some allowance for credit and debit accounts.
  • Amended Costilla Creek Compact of 1963:  The Amended Costilla Creek Compact establishes uses, allocations, and administration of the waters of Costilla Creek in Colorado and New Mexico.


         Rio Grande River Basin

Basin Updates
  • No updates at this time


 Additional Information