Colorado River is Drying up

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Illustration by Adrian Wong
Sources by Grist - Smithsonian

From its source high in the Rocky Mountains, the Colorado River channels water south nearly 1,500 miles, over falls, through deserts and canyons, to the lush wetlands of a vast delta in Mexico and into the Gulf of California. That is, it did so for six million years.

Climate change will likely decrease the river’s flow by 5 to 20 percent in the next 40 years, says geoscientist Brad Udall, director of the University of Colorado Western Water Assessment. Less precipitation in the Rocky Mountains will yield less water to begin with. Droughts will last longer. Higher overall air temperatures will mean more water lost to evaporation. “You’re going to see earlier runoff and lower flows later in the year,” so water will be more scarce during the growing season, says Udall.

Other regions—the Mediterranean, southern Africa, parts of South America and Asia—also face fresh-water shortages, perhaps outright crises.

There’s not enough freshwater to handle nine billion people at current consumption levels
— Patricia Mulroy, Colorado Water Research Foundation

The river has become a perfect symbol of what happens when we ask too much of a limited resource: it disappears. In fact, the Colorado no longer regularly reaches the sea.

Invasive plants, such as salt cedar and cattails, now dominate the delta, a landscape of seemingly endless mud flats where forests used to stand. And in the Gulf of California itself, shellfish, shrimp and waterfowl have declined dramatically as fresh water has dried up.