Bureau of Reclamation Implements Cooler Water Releases to Protect Native Fish Species

Bureau of Reclamation Implements Cooler Water Releases to Protect Native Fish Species

By Bob Hembree

The Bureau of Reclamation will implement cooler water releases from Lake Powell through Glen Canyon Dam to combat rising river temperatures and protect the threatened humpback chub.

Targeting Invasive Species

This targeted action is designed to disrupt the spread of invasive fish species like smallmouth bass, which thrive in warmer waters and threaten native fish populations in the Grand Canyon. The flows will begin once average river temperatures exceed 60°F at river mile 30 below the dam.

Refined Approach Based on Previous Success

Last year's operations were a success, and this year's effort is a refined approach—starting later, ending by October 20, and cooling the river downstream to river mile 30.

Environmental Impact and Risk Management

Rising temperatures allow invasive fish to pass through the dam and spawn downstream. If established, these predators could seriously harm protected species and be nearly impossible to remove. The "cool mix" flow helps reduce that risk while minimizing impacts to hydropower.

Collaborative Support

With support from the Colorado River Basin states and key federal agencies, this science-based approach strikes a careful balance between environmental protection and energy needs.