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Water District Lays Pipe to Cool Endangered Frog

Posted on: Friday, 30 December 2005, 09:00 CST

By Denis Cuff, Contra Costa Times, Walnut Creek, Calif., Contra Costa Times, Walnut Creek, Calif.

Dec. 30--BRENTWOOD -- Kermit the frog would find life easy with such help.

A Contra Costa County water supplier has laid 8 miles of pipe across rural grasslands to prevent California red-legged frogs from drying out and dying in the blistering summer heat.

The $163,000 project delivers water to 16 man-made ponds, breaking new ground in helping the threatened frog species celebrated in Mark Twain's story, "The Famous Jumping Frog of Calaveras County."

"It's unusual to create ponds for these frogs, but I don't know of anyone delivering them water," said Mike Nepstad, a federal biologist who approved the irrigation project in 2002 when he worked for the federal Fish and Wildlife Service.

The Contra Costa Water District created the water system last year to boost the frog's survival on lands near the district's Los Vaqueros Reservoir south of Brentwood.

It works like this:

-- Water is pumped from January through March to the ponds so they stay wet long enough for the baby red-legged frogs to grow up and hop off to underground burrows in fall.

-- The district cuts off water flows in time for the ponds to dry up in fall. This prevents non-native bullfrogs, which eat red-legged frogs, from invading the ponds. The bullfrogs need water year-round.

The water district created the 16 ponds a decade ago to offset frog habitat destruction caused by the construction of Los Vaqueros Reservoir.

But blistering East County heat left many of the ponds high and dry in summer, killing the juvenile frogs

"We had disappointing results at the ponds," said Bill Chilson, a water district watershed resources specialist.

The district trucked water to the ponds for a couple years but couldn't deliver it fast enough to offer much relief.

With the reservoir nearby, water district managers didn't need to look far for another solution.

"We have a huge water supply in our back yard, so why not make use of it?" Chilson said.

The district pumped reservoir water to 14 ponds, and spring water to two others. One pond was too far out of the way to irrigate.

Results so far have been encouraging because there are more red-legged frogs and no bullfrogs, said Dave Sterner, a private scientist hired by the district.

Another threatened species, the California tiger salamander, also has benefited from the project.

Replenishing and drying up the ponds mimics natural conditions in the frog's habitat, wildlife experts said.

To be sure, though, the frog water system creates a peculiar scene: concrete utility boxes that cover frog water valves miles from any buildings.

A water district worker pops off the top of the box and turns the water on and off according to the time of year.

A loss of natural conditions landed the frog on the federal threatened species list.

Before the Gold Rush, the red-legged frog was abundant throughout much of California, including streams, marshes and ponds around San Francisco Bay.

But the frog's fortunes declined as people caught them to serve as a delicacy for San Francisco restaurants. Development of wetlands dried up many frog homes. The bullfrog, a predator from East Coast states, invaded California and crowded out the smaller red-legged native.

The frogs retreated into ranchers' stock ponds in Contra Costa and Alameda counties, now the heart of red-legged frog territory in California.

"When the district built the reservoir, we made a commitment to manage the watershed land to protect the environment," Chilson said. "And the frogs are part of that."

Contact Denis Cuff at 925-943-8267 or dcuff@cctimes.com.

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Copyright (c) 2005, Contra Costa Times, Walnut Creek, Calif.

Distributed by Knight Ridder/Tribune Business News.

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Source: Contra Costa Times (Walnut Creek, Calif.)

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