Rob Viehl
303-866-3441 x3237
Instream Flow Program

In Colorado’s semi-arid environment, water is scarce with many competing demands placed on it by an ever-increasing population. Recognizing the need to correlate the activities of mankind with the reasonable preservation of the natural environment, the CWCB is responsible for the appropriation, acquisition, protection and monitoring of instream flow (ISF) and natural lake level water rights to preserve and improve the natural environment to a reasonable degree.

What is an instream flow or natural lake level water right?

These water rights are nonconsumptive, in-channel or in-lake uses of water made exclusively by the CWCB for minimum flows between specific points on a stream or levels in natural lakes. These rights are administered within the state’s water right priority system to preserve or improve the natural environment to a reasonable degree.

What is the purpose of this type of water right?
The CWCB’s instream flow and natural lake level water rights protect diverse environments in Colorado including:
  • Coldwater and warm water fisheries (various streams and lakes)
  • Waterfowl habitat (Gageby Creek)
  • Unique glacial ponds and habitat for neotenic salamanders (Mexican Cut Ponds and Galena Lake)
  • Riparian vegetation, unique hydrologic and geologic features (Hanging Lake and Deadhorse Creek)
  • Critical habitat for threatened or endangered native fish (Yampa and Colorado River)
Status of the CWCB ISF Program
Since 1973, the CWCB has appropriated instream flow water rights on more than 1,600 stream segments covering more than 9,250 miles of stream and 480 natural lakes. The CWCB has completed more than 35 voluntary water acquisition transactions. For more information about these activities, select an option below: ­
  • Instream Flow Appropriations: Includes details about the appropriation recommendation process, as well as proposed and contested instream flow appropriations. ­
  • Water Acquisitions: Includes details about the voluntary program that allows existing water rights to be donated, sold, leased or loaned to the CWCB. ­
  • Monitoring and Enforcement: Includes details about how the CWCB protects the state’s ISF water rights.