Expensive fix due at Fern Ridge.

Byline: Mark Baker The Register-Guard

FERN RIDGE - The U.S. Army Corps of Engineers is keeping a closer eye on the drainage system at the dam here after discovering that it might be leaking.

The corps, which owns and operates the 62-year-old dam at Fern Ridge Lake, fears that a pipe that stretches for more than a mile at the dam's bottom needs replacing to solve the problem.

The entire drainage system, an elaborate maze of underground metal pipes, would cost about $6 million to replace, said James Beal, the corps' park ranger who manages the dam. And the 40-foot-deep, man-made lake that covers about 93 acres would have to be drained to put a new system in, he said.

Beal hopes the corps can get the money appropriated from Congress in time to install a new system in the summer of 2004. But he also realizes that federal money is hard to come by these days.

It would take an entire summer to do the work, he said, thus shutting the lake down for recreation.

Ever since the possible leakage was discovered last summer, the corps has been monitoring the lake's water level and clarity at least once a day, Beal said.

There's always the possibility that an emergency could arise and the lake would have to be drained immediately, he said. But "right now, our plan is to operate the (dam) as normal" - at least until the summer of '04.

The corps recently hired a company to view the dam's drainage system with a remote-control camera, but the camera got snagged trying to find its way through the system's sharp curves, Beal said.

The corps is planning to build a series of metal shafts that would be inserted into pipes that connect with other pipes that feed into the main drainage pipe. That way the remote camera can snake through the shafts and not get hung up, he said.

The drainage system keeps the earth-fill dam relatively dry by lessening the water pressure found within the dam. But if it is indeed leaking, that could create a serious and dangerous problem, especially if it leaked quickly while people were on the water, Beal said.

"Safety is our No. 1 concern," he said.

The dam, 6,330 feet long and only 44 feet tall, was built in 1941 with flood control and irrigation in mind. The lake it produced, however, was almost immediately embraced for its recreational potential.

During warm spring and summer days, the lake is a popular destination for fishing, boating, waterskiing and the like, and people flock to the parks that surround it for barbecues and family gatherings.

What got the corps' attention last summer were several "depressions," or sinkholes, in the dam's grassy down-slope alongside Clear Lake Road to the north, Beal said. They look like large dents in the grass and are currently marked with stakes. Each depression is surrounded by what looks like a large circle because the grass has been mowed around them to make it easier to monitor.

The corps believes the depressions could very well be related to silt and other sediments collecting in the drainage pipe, thus preventing proper water drainage, Beal said.

Whether the leakage is as serious as the corps believes, the drainage system needs replacing because it is just plain worn out, Beal said. "It's reached the end of its lifespan."

CAPTION(S):

James Beal, park manager with the U.S. Army Corps of Engineers, tracks water flows at the base of the levee on the north side of Fern Ridge Lake.