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Division 4 (Montrose): Gunnison River Basin 
DWR > Division Offices > Division 4 (Montrose)
 

Division 4 Location MapClick here to view enlarged version of the Division 4 Water Districts

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 it’s apportionment of water under the Colorado River Compact by providing stored water for use in-state and to ensure that the upper basin can meet their flow obligations at Lee Ferry, Arizona; thus reducing the potential for a call from the lower basin states.