West’s water worries rise as Lake Mead falls — USA Today #ColoradoRiver

Receding Lake Mead (2010)
Receding Lake Mead (2010)

From USA Today (William M. Welch):

“I hate to see it,” [Allen Keeten] the 58-year-old truck driver from Kenesaw, Neb., says, peering over the side of the massive concrete dam on the Colorado River. “Nowadays you’ve got to be careful when you are out on a boat because of all the exposed ground.”

Like a giant measuring stick in the desert, the dropping water level of Lake Mead, the nation’s largest man-made reservoir, provides a vivid representation of the drought that is gripping the Southwest and much of the West…

Only a fraction of the river’s flow makes it to Mexico as millions of acre-feet leave the Colorado River system through pipes and aqueducts for use by farms, businesses and homes of the southwestern United States — the water rights apportioned by decades of court cases, contracts and legislation.

Now that measuring stick is drier than ever. Federal water managers say Lake Mead is just 39% full. The water level fell in July to its lowest level since 1937, when water began backing up to form Lake Mead after the dam was completed…

As the water recedes, left behind is a broad white stripe of mineral deposits on the lake’s shoreline, as visible as a dirty bathtub ring. New islands poke through the lake’s lowered surface, and buoys stand amid desert scrub.

Entire coves and miles of lake fingers have dried up, forcing boat landings and marinas to close or relocate. Marina operators who want to stay in business have had to move their floating docks — and the fuel, electricity, water and sewer lines that serve them — in a costly chase to stay on the water…

Lake Powell is down, too, though not as badly at 52% of capacity. The entire Colorado River system of four impoundments, ending with Lake Havasu in Arizona, has just over half the water it is capable of holding this summer.

Still, federal water managers are optimistic that they can avoid reducing agreed-upon amounts of water to all who depend on it, at least until next year. Beyond that, much depends on how long drought continues…

Water from the Colorado River makes up about a quarter of all water that flows from Southern California taps, and water from the Sierras makes up about 30%, with the remainder coming from local sources, groundwater and reclaimed water…

An especially wet winter would help. A big snowpack in 2011 raised Lake Mead nearly 50 feet in one season.

“We need several above-average years to replenish the storage,” Bunk says.

But the trends are worrisome. While California is in the third year of drought, Bunk says Colorado River data suggests this is the 15th year of a broader regional drought, interrupted by an occasional wet year.

Scientists studying tree rings for clues to past water seasons calculate that the period since 2000 is one of the driest in centuries. Bunk says the evidence shows the past 15-year period ranks in the driest 1% of the past 1,200 years.

More Colorado River Basin coverage here.

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