Arkansas River Basin

The Arkansas Basin is spatially the largest river basin in Colorado covering an area of 28,268 square miles (27 percent of the area of Colorado) in the southeast portion of the state. Major tributaries include Apishapa River, Purgatoire River, Horse Creek, and Big Sandy Creek.

Quick Facts
Description Value (approximate)
Irrigated Acres (2011) 1,2 249,450
Decreed Points of Diversion 2 8,660
Decreed Wells 2 16,550
Major Reservoirs 3
  • John Martin Reservoir
  • Pueblo Reservoir
  • Great Plains Reservoir System 
Normal Storage (acre-feet)
  • 618,000
  • 357,678
  • 265,552
Major Imports into Basin 3
  • Boustead Tunnel into Lake Fork Creek
  • Twin Lakes Tunnel into Lake Creek
  • Homestake Tunnel into Lake Fork Creek
Average Diversions (acre-feet) (1971-2003)
  • 49,706
  • 39,204
  • 24,764
Major Exports from Basin 4
  • Rocky Ford Ditch to Aurora (by exchange)
Maximum Annual Diversion (acre-feet)
  • 15,656

Irrigated land data is currently only available for areas below Pueblo Reservoir.
2 Source: CDSS, total values derived from GIS Data for Arkansas Basin 
3 Source: Statewide Water Supply Initiative Fact Sheet for Arkansas Basin, CWCB, 2006
4Source: Water Supply Fact Book, Aurora Water, 2010-2011


Compact Facts
  • Arkansas River Compact of 1948:  The Arkansas River Compact apportions the uses of the Arkansas River and the benefits of John Martin Reservoir between Colorado and Kansas.  The Compact was negotiated  following several instances of litigation between the States in the U.S. Supreme Court, notably Colorado v. Kansas, 320 U.S. 383 (1943).


        Arkansas River Basin

Basin Updates
The Arkansas River Decision Support System (ArkDSS) Feasibility Study final report is available at the link below.


 Additional Information