Colorado gets most of its water from melting snowpack, and the situation has worsened in the past two years as the soils have become so d...
Colorado gets most of its water from melting snowpack, and the situation has worsened in the past two years as the soils have become so dry that much of the runoff has been absorbed before reach the river. This year, runoff in the upper Colorado basin, which reaches Lake Powell, is expected to be only about two-thirds of average.
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The level of Lake Powell is currently at an elevation of 3,523 feet, 177 feet below capacity. The water intakes that allow water through the dam to generate hydroelectricity are at 3,490 feet.
In a letter to state water officials in April in which she proposed keeping water in Lake Powell, Ms. Trujillo wrote that if the lake reached 3,490 feet, “the western power grid would be at risk. and uncertain instability”.
Hydroelectricity is useful for maintaining the stability of power grids, in part because the amount of electricity produced can be quickly changed to help the grid meet demand.
In addition, Ms. Trujillo wrote, water supplies in the western and southwestern states “would be subject to increased operational uncertainty.” The water supply of Page, Arizona, near the dam, and a nearby Native tribe, would be particularly at risk, she wrote, because their intake is at about the same elevation as hydroelectric inflows.
The dam itself would face “unprecedented reliability challenges”, Ms. Trujillo wrote, because with the hydroelectric intakes above water level, water from the lake would have to be channeled through the dam in using lower tunnels that were not designed for continuous use. “We are approaching operating conditions for which we have very limited actual operating experience – and which occurred almost 60 years ago,” she wrote.
Brad Udall, a senior climatologist at Colorado State University, said concerns about the reliability of the power grid and the dam hadn’t really been raised in any drought contingency plans over the past few decades.
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