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| Grad students in W&M’s School of Marine Science at VIMS had a chance to observe California’s drought first-hand during a recent tour of the state’s waterways. The students are part of Milliman & Canuel’s “Rivers” course at VIMS. From L: Professors John Milliman and Chris Hein; grad students Zhengui Wang, Erika Schmitt, Kelsey Fall, and Danielle Tarpley; Professor Elizabeth Canuel; and grad student Amanda Knobloch. |
Professor John Milliman of the Virginia Institute of Marine Science has studied a lot of rivers during his nearly 50-year research career. Lately he doesn’t like what he sees.
Milliman—who has compiled the world’s largest river database with records from 1,534 rivers around the globe—is troubled by the confluence of a growing human population, increased water use, and decreased river flow. He sees the pattern worldwide, with his attention most recently focused on the drought-parched American West.
California’s current drought has made the always-contentious task of distributing the state’s water even more difficult, says Milliman, because it’s affecting not only the typically arid southern regions of the state, but the historically wetter northern regions as well.
“The Sacramento, California’s largest river, is the major water source for not only the San Francisco area but for Southern California,” says Milliman. “But during the last two winters it’s had very little discharge. There has been little precipitation in the mountains, either snow or rain, and the discharge last winter and spring, as well as this winter, was only about half of normal.”
Based on his discovery of a strong correlation between precipitation in the western U.S. and the “Pacific Decadal Oscillation”—a 40-year fluctuation in ocean heat—Milliman also cautions that the current drought is likely to last for 10 to 15 more years.
“Oceanic drivers affect precipitation and discharge on the West Coast,” he says. “The PDO is the controlling force, with almost a perfect correlation between a cold PDO and low discharge in rivers across the southern tier of the U.S.—including the San Diego, Salinas, San Juan, Colorado, and Suwanee.”
Excerpted from http://www.wm.edu/news/stories/2014/river-expert-warns-of-looming-global-water-crisis221.php
