Moab: University of Utah Center for #ColoradoRiver Studies presentation recap #COriver #aridification

Colorado River near Moab, Utah.

From The Moab Sun News (Rachel Fixsen):

On Feb. 20, the University of Utah Center for Colorado River Studies hosted a presentation and panel discussion in Moab on research being conducted on and policies being considered for Lake Powell. Scientists, activists, authors, and historians shared their perspectives on various aspects of the river, the dam, and the reservoir to a full house at Star Hall. The complicated history of river engineering and water allocation sets the stage for an uncertain future of the management of the West’s precious resource.

“We can’t talk about the future of this reservoir and how its managed unless we digest some basic facts,” said Dr. Jack Schmidt, professor of watershed sciences at Utah State University, at the presentation, before he and others gave an overview of the reservoir’s history and parameters.

The presentation was part of an effort by the Center for Colorado River Studies to help the public understand the complexity of the natural systems and political agreements surrounding the Colorado River…

Water levels in Lake Powell and Lake Mead have reflected this decreased flow. In 2005, Lake Powell dropped to its lowest level since it first filled up in 1963, sinking to 3,555 feet above sea level, just barely high enough to keep from exposing the intakes for the hydroelectric generator at the dam and causing damage to the facility.

How much electricity the turbines in the bowels of Glen Canyon Dam can generate depends upon how much water is delivered from the Wind River Range of Wyoming and the high mountains of Colorado into Lake Powell. Photo/Bureau of Reclamation.

“Here’s an important number,” Schmidt told the audience at Star Hall. “If the reservoir elevation gets lower than 3,490 feet above sea level, then water cannot be taken into those penstocks, because then air is entrained, and if air is entrained, you get the phenomenon of cavitation in the turbines, which will destroy the turbines.”

He went on to explain that water managers don’t want to get too close to that absolute limit, and they set a bottom threshold of 3,525 feet above sea level for Lake Powell.

Policymakers must constantly consider how supply and demand are affected by climate and natural systems, new infrastructure and aging infrastructure, population growth and changes in land use, and scientists’ and researchers’ evolving understanding and modeling of how these factors will play out in the future…

To prepare for a renegotiation of interstate agreements, scientists and researchers have been studying the Colorado River basin and all the systems that comprise it. The presentation at Star Hall illustrated just how complex the issue is. Glen Canyon Dam itself has been controversial nation-wide since its inception. Environmentalists, river runners, and archaeologists to this day lament the loss of the natural canyon flooded by the dam, which was filled with Native American artifacts and wild riparian ecosystems. That dam and other infrastructure have changed many properties of the river, from flow rate, to temperature, to fish populations, to evaporation patterns, to the shape of the riverbed. As scientists study the new patterns of the river, they try to create models that can accurately predict future behaviors and conditions of the river. For example, by studying how the river moves and deposits sediment, scientists have variously predicted an operable life span for Lake Powell of 100 to 150 years. These models and data sets can help steer management agreements.

“The current interim guidelines aren’t going to work forever,” said Erich Balken, executive director of the Glen Canyon Institute, a Salt Lake City-based nonprofit devoted to the restoration of Glen Canyon and the Colorado River.

The organization is advocating for a policy they call “Fill Mead First,” which Balken briefly discussed at the Star Hall event. The policy would allow the downstream Lake Mead to be filled to capacity before starting to store water in Lake Powell. The group recommends not decommissioning Glen Canyon Dam, a step that has been taken at other dam sites around the country, but drilling diversion tunnels around it to allow the river to return to its natural flow.

The hydroelectric power plant driven by Lake Powell would be temporarily shut down, and intakes to power the facility would be installed in the diversion tunnels. Glen Canyon would be returned to its natural state until the necessity arose to store more water than Lake Mead could hold.

The idea is politically difficult because Lake Powell serves as a kind of “bank account” of water that helps upper basin states ensure that they meet their water obligations to the lower basin states. Beyond Lake Powell, the water essentially belongs to the lower basin. The dividing line maintains a tension between the regions…

At the same time that Colorado River users are beginning the renegotiation process, the state of Utah continues to pursue water projects that affect the Colorado River and Lake Powell. Local leaders in Washington County are exploring a “Lake Powell Pipeline,” a 140-mile pipe that would pump water from Lake Powell to the St. George area.

Lawmakers in Salt Lake City are considering the possibility of diverting water from the Green River and the Bear River, the former of which is a tributary to the Colorado and eventually feeds Lake Powell, to water users on the Wasatch Front. More water rights have been allocated from the Colorado River than there is actual water to distribute, and historically, the first users of the existing water, and the owners of water infrastructure, retain the rights to continue using the water.

More information may be found on the University of Utah Center for Colorado River Studies website, https://qcnr.usu.edu/coloradoriver/

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