Colorado River Mile -12 Slough Channelization

Working to prevent the spread of nonnative fish below Glen Canyon Dam

A project in Glen Canyon National Recreation Area will prevent warm water nonnative fish species from spreading in the Colorado River below Glen Canyon Dam. Reshaping the slough at river mile -12 below the dam to enable water to flow more freely will hinder reproduction of nonnative smallmouth bass at this location and deter the fish from spreading further into Glen, Marble, and Grand canyons.

Construction Timeline

Construction is planned to start at the -12 mile slough on March 1, 2025. To prepare for that start date, equipment staging and movement will begin next week (February 24-28). On Wednesday, February 26 a barge will be assembled at Lees Ferry from approximately 7 a.m. to 1 p.m. During this period, access to the river from the dirt boat launch at Lees Ferry will be restricted for public safety as a crane moves barge sections from semi-trailers into the river. The contractor may have 30-minute breaks between barge sections so boaters can access the river. Full access will resume once the barge sections have been put into the river. On the morning of Thursday and Friday, Feb. 27 and 28, construction equipment will be loaded onto the barge from the concrete ramp. Access will be restricted during this period as well, though this process should take less than an hour each morning. Boat traffic may be slowed as the barge transports equipment to the slough and back on Feb. 27 and 28. Further details about delays will be shared in social media posts and website updates.

Project Images

Images of the slough project in progress.