#ColoradoRiver: Research Evaluates Impacts of Lake Powell’s Troubling Decline #COriver

A high desert thunderstorm lights up the sky behind Glen Canyon Dam -- Photo USBR
A high desert thunderstorm lights up the sky behind Glen Canyon Dam — Photo USBR

Here’s the release from the Yale University School of Forestry & Environmental Studies (Kevin Dennehy):

The Colorado River provides water to roughly 40 million people in the southwestern U.S. and Mexico, irrigates some 4.5 million acres of farmland, and can produce more than 4,200 megawatts of electricity for regional customers. But a historic, prolonged drought and increased seasonal variability — in addition to rampant exploitation — has made it increasingly difficult to depend on the iconic river’s water flow.

For instance, Lake Powell, a human-made reservoir created by the Glen Canyon Dam, is currently less than half full, with vast implications for water availability, energy production, and recreation.

Looking Upstream,” a new report produced by four students at the Yale School of Forestry & Environmental Studies (F&ES), evaluates the factors contributing to acute vulnerability to water shortages in Lake Powell and how it will impact the river’s entire Upper Basin.

Led by Lindsey Ratcliff ’16 M.E.M., the 119-page report explores how the declining reservoir levels are impacting water supplies, hydropower, recreation, and the regional environment. Their findings were based on dozens of consultations with managers and experts across the region and a comprehensive literature review.

Among the many impacts, they find that dropping water levels will increase water supply scarcity and reduce recreational visitors by more than a quarter. And, they say, it might drive a surge in the cost of so-called firming purchases, or the wholesale electricity costs borne by the power authority to assure power delivery in the absence of hydropower generation.

“The amount of water in Lake Powell is one of the primary factors contributing to how much hydropower can be produced at Glen Canyon Dam,” said Ratcliff. “When the reservoir declines, more power has to be purchased on the wholesale electricity market. Our study found that this could increase costs by a factor of five to 10, depending on hydrological factors and dam operations.”

In addition to Ratcliff, who assessed the factors contributing to Upper Colorado River Basin water supply vulnerability, the team consisted of Michael Johnson ’16 M.E.M., who examined different environmental impacts; Rebecca Shiveley ’17 M.E.M., who conducted a statistical analysis of the impacts on recreation, and Leanne Weiss ’16 M.E.M., who studied the impacts on hydropower.

The project was produced for Douglas Kenney of the Western Water Policy Program at the University of Colorado.

The project complements an earlier report, “The Bathtub Ring: Implications of Low Water Levels in Lake Mead on Water Supply, Hydropower, Recreation, and the Environment,” which examined similar challenges in the Colorado River’s Lower Basin, where Lake Mead is also facing historic water lows. Lake Mead, which was created by the building of Hoover Dam, reached it lowest levels ever this spring. That report was conducted by students at the University of California, Santa Barbara.

“We hope that a better understanding of these impacts will strengthen efforts and promote continuous dialogue between decision-makers creating solutions to basin-wide imbalances and drought contingencies,” Ratcliff said.

The research was conducted as an independent study under the guidance of F&ES Prof. Brad Gentry, who described the work as a sort of “reverse case study” that integrated an array of critical information to help guide managers to make more informed planning decisions.

“In that sense it’s a classic F&ES exercise of bringing the best science to bear on important issues and trying to figure out useful information that can guide pathways forward,” he said.

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