Thursday June 1, 2023
Bureau of Reclamation —
Protecting and responding to threats of the Colorado River endangered fishes (Colorado pikeminnow, razorback sucker, bonytail, and humpback chub) are an important part of the Bureau of Reclamation’s mission. Threats such as fish entrainment in water diversions, have long been recognized by resource managers as a threat to native, especially endangered and threatened fish in the Colorado River Basin.
Fish entrainment is the unwanted passage and loss of fish through a water intake, for example, when fish are transported with the flow of streams, creeks or rivers that are being diverted for irrigation and other uses.
Though construction of fish screens has been historically the recommended alternative for protection of fish at most Reclamation projects, there are still many concerns that arise with the use of screens, especially when used in canals. The screens often become clogged with debris and are raised to allow the water to pass through. Additionally, smaller fish can become impinged on screens and in the aftermath are killed. Engineers and biologists have recognized that screen use in these waterways can be a significant source of increased, not decreased, fish entrainment and their usage needed to be re-evaluated.