Redlands Diversion Dam Fish Passage- Gunnison River, CO
The Redlands Diversion Dam
The Redlands Diversion Dam, located on the picturesque Gunnison River about three miles upstream from the confluence with the Colorado River near Orchard Mesa, Colorado, was built in 1907. This vital infrastructure serves two main purposes: irrigation and power generation, diverting approximately 500,000 acre-feet of water annually from the Gunnison River into the Redlands Canal, which flows through the Grand Valley to support these needs. Photos below (from Redlands Water and Power) show the early dam construction and Grand Valley farmers.
The Fish Passage at Redlands Diversion Dam
The Redlands Diversion Dam Fish Passage, built in 1996 by water users and partners of the Upper Colorado River Endangered Fish Recovery Program, is located on the Gunnison River, three miles upstream from where it meets the Colorado River near Orchard Mesa, Colorado. This vital fish passage operates from early spring snowmelt until late fall, when river temperatures drop. As the first fish passage of its kind in the Upper Colorado River Basin, its primary goal was to allow two federally protected species, the Colorado pikeminnow and razorback sucker to migrate upstream. However, it has also greatly benefited many other native fish species, providing access to 50 miles of designated Critical Habitat for endangered fish on the Gunnison River and has helped over 180,000 native fish migrate up the Gunnison River since its inception.
Total Number of all Native Fish To Pass Through Redlands Diversion Dam Fish Passage 1996-2024
Number of endangered Colorado Pikeminnow To Pass Through Redlands Diversion Dam Fish Passage
Total Number of endangered bonytail To Pass Through Redlands Diversion Dam Fish Passage
Number of threatened humpback chub To Pass Through Redlands Diversion Dam Fish Passage
Total Number of endangered razorback sucker To Pass Through Redlands Diversion Dam Fish Passage
The Innovative Fish Passage Structure
An aerial view of the Redlands Diversion Dam Fish Passage on the Gunnison River near Orchard Mesa, Colorado. There are a series of baffles which enable fish to swim around the river obstruction, one step at a time. Photo by Bureau of Reclamation
Shortly after construction of the fish passage, native fish attempting to migrate upriver of the Redlands Diversion Dam for reproduction and other biological reasons were able to do so. This infrastructure has significantly contributed to fish recovery efforts in the basin. The photo above is one of the first large endangered Colorado Pikeminnow to utilize the newly built fish passage and released upriver of the dam in 1996.
How the Redlands Diversion Dam Fish Passage Works
1) Below these grates are the entrance to the Redlands Diversion Dam fish ladder. Migrating fish will enter here, eventually swimming around the dam to continue their journey upriver.
2) Fish swim up these baffles and are held in the final “V trap” chamber before being released on their way up the Gunnison River.
3) Once the fish trap is drained, the fish are gathered and sorted before being sent on their way.
4) The fish are brought from the fish trap to a sorting table where they are separated by species.
5) Biologists are given the opportunity to acquire important data on endangered fish including, length, weight, PIT tag numbers, sexual maturity and more.
6) Fish are then released from the holding tank through a pipe leading to the Gunnison River above the dam, giving them access to nearly 50 miles of Critical Habitat that had been inaccessible for almost 80 years.
When rare species like Colorado pikeminnow are documented in the Redlands Diversion Dam Fish Passage, fish biologists often gently transport the rare animals 40 miles upriver to Escalante Canyon where they are released. This quick transport increases the probability they stay in the Gunnison River long-term. Above are photos of a few of these lucky Colorado pikeminnow that were transported to Escalante Canyon to be released.
Link to Redlands Diversion Dam Fish Passage Annual Reports
Relevant Links For Students and Supporters
Grand Valley Water Users Association
Grand Junction Fish and Wildlife Conservation Office
Historical Accounts of the Upper Colorado River-GREAT STORIES AND FISH PHOTOS!!!!!
History of Redlands Water and Power
Upper Colorado River Endanger Fish Recovery Program –“Upper Colorado” Website
Upper Colorado and San Juan River Endangered Fish Recovery Programs Website
Directions to the Redlands Diversion Dam Fish Passage
Directions to Redlands Diversion Dam from Orchard Mesa Cemetery
- Turn right on B 3/4 Rd. / Legacy Way.
- Slight left on 26 7/8. Rd.
- Continue onto 26 3/8 Rd.
- Turn right to at end of road to get to the fish passage (just upriver of boat ramp).
“In the West, when you touch water, you touch everything.”