Colorado Division of Water Resources Division 4 Updated:05/2023

Gunnison River Basin (Montrose)

Division 4 includes the Gunnison River basin, San Miguel River basin, lower reaches of the Dolores River basin, and the Little Dolores River basin.  Our staff administers water rights for water users, consults on water court cases, measures water flow, inspects dams to determine safe water storage levels, and maintains gaging stations and water records within these basins.  Most streams within Division 4 are considered "over-appropriated", meaning that enough water does not exist during part of the year to satisfy all decreed uses.  The Aspinall Unit of the Colorado River Storage Project is located in the Gunnison basin.  Aspinall Unit dams include Crystal, Morrow Point, and Blue Mesa.  Blue Mesa Dam impounds the largest reservoir in the State at a capacity of 940,800 acre-feet.  These reservoirs are critical in protecting Colorado’s ability to fully develop its apportionment of water under the Colorado River Compact by providing stored water for use in-state and to help ensure that the upper basin states can meet their flow obligations at Lee Ferry, Arizona; thus reducing the potential for a call from the lower basin states.


Contact Colorado Division of Water Resources Division 4

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Colorado Division of Water Resources Division 4 is not employed by or affiliated with the Colorado Land Conservation Assistance Network, and the Network does not certify or guarantee their services. The reader must perform their own due diligence and use their own judgment in the selection of any professional.


Contact Colorado Division of Water Resources Division 4

Gina DeArcos
Program Assistant
1541 Oxbow Drive
Suite 1625
Montrose, CO  81401
Phone: (970) 249-6622

Service Area

Services provided in:
  • Delta County, Colorado
  • Gunnison County, Colorado
  • Hinsdale County, Colorado
  • Mesa County, Colorado
  • Montrose County, Colorado
  • Ouray County, Colorado
  • Saguache County, Colorado
  • San Miguel County, Colorado