FILL MEAD FIRST?
Dr. Jack Schmidt, professor, Utah State University, and former director of the Glen Canyon Monitoring and Research Center
Decades ago, in his book “Monkey Wrench Gang,” Edward Abbey imagined unplugging the Colorado River at Glen Canyon Dam and draining Lake Powell. More recently, the Salt Lake City-based Glen Canyon Institute has imagined the same thing, arguing that diminished flows of the river can more efficiently be stored in just one reservoir, Lake Mead.
“Whether you think the idea is crazy or not—let’s assume that most people think it’s crazy— it’s an idea that won’t go away,” said Jack Schmidt, a professor at Utah State University. “So it’s worth thinking about.”
Schmidt has thought about the idea a lot, reading many papers and bringing to his research personal observations from his years overseeing an adaptive management program in the Grand Canyon.
Understanding evaporation rates from the two reservoirs is crucial. Even today, he said, “We don’t understand evaporation very well,” he reported. Evaporation of Lake Mead has been estimated to be 7.5 feet per year. That 40- year-old figure is incorrect he said. He has concluded that the two reservoirs together lose 1.1 million acre-feet, or more than three times the entire allocation of the river to Nevada. “That’s not a trivial number.”
It doesn’t matter where you store the water, in Powell or Mead: there really is no savings of water from evaporation. But noting the lingering uncertainty about viable numbers, he also noted that the Bureau of Reclamation has now issued a contract to study evaporation from Lake Powell. He said he believes he had something to do with that quest.
Seepage is, if anything, even more complicated. He explained the complex science delving into how and how much water moves into the river, into the reservoirs and around the dams thorough groundwater.
Bottom line? Too much uncertainty remains for making good decisions about where water should be stored and whether, as the Glen Canyon Institute argues, Powell should be gradually decommissioned after first drawing it to down to minimum power pool, for hydroelectric production.
But the proposal does have merit, he said, as a catalyst for thought. “It causes us to scratch our head and say, ‘We need to think about just how we think about water storage and environmental protection in the southern Colorado River Plateau.”