Lake Powell is just a quarter full, its surface now at 3,536 feet above sea level — 46 feet from the minimum level to produce hydropower.
By Brandon Loomis | Arizona Republic
The federal government must rapidly prepare plans to redesign Glen Canyon Dam’s plumbing to keep the Colorado River flowing through the Grand Canyon as the water levels behind the dam continue to fall, a coalition of environmental groups warned on Wednesday.
Lake Powell is just a quarter full, its surface now at 3,536 feet above sea level — 46 feet from the minimum level to produce hydropower — and falling after the early summer gush of snowmelt from the Rocky Mountains. Two more dry winters could push the reservoir past that point, according to forecasters, and ultimately dam managers may have to open bypass tunnels more than 100 feet deeper just to keep the river flowing.
If it comes to that, the river advocates and their new analysis caution, those tunnels will prove insufficient to release as much water as the Southwest counts on to pass through the Grand Canyon and restock Lake Mead each year.
“This system needs flexibility and it needs it now,” said Eric Balken, whose Glen Canyon Institute partnered with the Utah Rivers Council and the Great Basin Water Network on a new report urging action.
Lake Powell’s elevation has dropped more than 160 feet since it was essentially full at the turn of this century, and the pace has quickened in recent years. Dropping below what the outlets were designed to handle would jeopardize delivery of the water needed to irrigate farms and fully supply cities from Phoenix and Las Vegas to Los Angeles and Tijuana.
The groups’ quest is to persuade the U.S. Bureau of Reclamation, which manages the dam, to study how to keep the river flowing if, as their analysis suggests, climate change and overuse push the system to a breaking point in coming years. Their preferred alternatives are to either expand the capacity of the bypass tunnels or build new tunnels at the dam’s base to allow the river to flow even if Lake Powell empties.