As a result of warmer Colorado River temperatures, the Bureau of Reclamation announced in early July it would begin releasing deeper, and therefore, colder water starting July 9 from Lake Powell through Glen Canyon Dam. The purpose is to disrupt the establishment of smallmouth bass, which could negatively affect populations of threatened humpback chub below the dam. 

The need for these flows was triggered after the average observed daily water temperatures reached smallmouth bass reproduction thresholds above 15.5 degrees Celsius (60 degrees Fahrenheit) at the confluence of the Colorado River with the Little Colorado River. Read the news release.

Angler Jim Strogen has a good article in the Payson Roundup about the project. Read the article.