The Runoff: Reclamation’s cool water releases sound fishy to these scientists
In an effort to prevent smallmouth bass — an invasive, voracious predator that feasts on native fish, including the threatened humpback chub — from establishing populations below Glen Canyon Dam, the U.S. Bureau of Reclamation in early July began releasing colder water from Lake Powell via the river outlet works (which are 100 feet lower in a cooler part of the water column) in addition to the hydropower penstocks. … Reclamation chose this option with the goal of keeping water temperatures below the dam under 15.5 degrees Celsius (60 degrees Fahrenheit), which is too cold for smallmouth bass to thrive. But a report by a group of scientists at the Center for Colorado River Studies at Utah State University says that factors other than temperature should be taken into consideration when trying to manage the nonnative species.