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Lots to unwind if Glen Canyon Dam shuttered too soon

Believe it or not, massive hydroelectric dams do not last forever. And in the case of Glen Canyon Dam, the end might come as soon as the year 2036. That’s the earliest that the federal government has said it might stop managing the dam for power and water storage. By then, it would be 72 years old. On the other hand, federal officials could change their minds and extend the life of the dam another 20 years. Or they could hand it over to the Navajo Nation or any number of Colorado River Basin states that might want to foot the mounting bills for dredging and structural upkeep along with downstream management obligations in the Grand Canyon.

 

Glen Canyon Dam, unlike its older and bigger sibling, Hoover Dam, farther downstream near Las Vegas, has long been an underachiever. It is anchored in porous sandstone, meaning Lake Powell loses a lot more water to leakage than just to evaporation. And the silt that washes from the Rocky Mountains upstream reduces water storage and eventually will reach the base of the dam, threatening the structural integrity and operational efficiency of the dam. Downstream, the Colorado River runs cold and clear instead of its pre-dam lukewarm and muddy. That has changed the entire ecosystem at the bottom of the Canyon, and scientists are at a loss over how to put the genie back in the bottle. They have tried electrocuting invasive brown trout to protect the native humpback chub and introduced insect pests to devour the invasive tamarisk along the shoreline. Periodic high-flow releases from Lake Powell attempt to dislodge sand deposits around the mouth of the Paria River to reestablish beaches lower down the river. But to date, those measures and more have done little to resuscitate the pre-dam ecosystem. Nonetheless, various tribes, states and power companies recently signed off on a 20-year extension on federal dam management, which is good news for the city of Page and others who depend on consistent management of lake levels to attract tourists. Once the dam is decommissioned (its estimated maximum lifespan is 85 to 100 years), lake water presumably would be released and Page’s tourism industry would have to reorient itself toward a landscape of deep river canyons.

 

For now, though, Page in its current configuration has at least a 20-year lease on life. The coal-fired Navajo Generating Station, which in part depends on nearby Page for employees and support services, is set to retire its final power unit in 2044. Technically, NGS is not dependent on an operational Glen Canyon Dam. But it uses Lake Powell for steam production and cooling water, and its electricity powers the pumps that bring Colorado River water via canals to Phoenix and Tucson. Drawing water directly from the river might work in the spring, but not during dry periods. In other words, once a mighty dam goes up, taking it down – figuratively speaking – is no simple task. The web of dependencies that Glen Canyon has created after 52 years is complex. If we were allowed to bet, we’d put money on that 2036 management deadline being extended. By then, there might even be a way to increase the dam’s lifespan so that the city of Page is still around to celebrate its own centennial in 2057.

Thank you Ron