Corps restoring dam to pre-testing condition

Presenting a possible sign that the U.S. Army Corps of Engineers is finished with poking holes in Success Dam, workers have been sealing up and restoring all the sites where holes were drilled to test the integrity of the earthen retaining structure east of Porterville.

“They are restoring the dam back to the condition it was before testing began,” said Calvin Foster, manager with the Corps who has overseen the dam for more than two decades.

The Corps began testing the strength of the dam about a decade ago, recalled Foster, when studies were began to see if the dam spillway could be raised so the dam could hold more water.

Those initial tests, which began around 2000, led to concerns over the safety of the dam, including the potential of collapse if a strong earthquake were to occur along a fault near Porterville when the lake was full, as well as seepage.

Today, officials say those concerns are no more. They have determined the chance of the earthquake is far too remote and that seepage is not as big an issue as first thought.

The concerns led to the Corps restricting the amount of water that could be held behind the dam. At one point, no more than 29,000 acre feet of water was allowed; the reservoir can hold 82,000 acre feet. Over the past few years, those restrictions have been eased, at first to 40,000 acre feet and last year to more than 65,000 acre feet, the most water the dam has held in nearly a decade.

Foster said the work going on at the dam now shows that officials are much closer to allowing the reservoir to fill to capacity if there is enough runoff.

“Last year, we went to 645 [feet elevation]. I would expect at least that or even higher this year,” he said Monday. The elevation is the level of the water behind the dam. An elevation of 645 feet translates to roughly 65,000 acre feet of water.

He said officials are still analyzing all the data and then the “senior oversight team” will make a determination on how high to allow the pool to reach this summer. He expects that decision to be made by early spring.

Foster said workers first sealed the holes that were drilled, and now they are replacing the rock on the face of the dam. Restoration on the Rocky Hill side is also being done where burrowing sites were drilled.

Marina still a ways off

While it appears the dam is much closer to holding as much water as possible, Foster said getting a marina back at the lake will take longer.

“It’s not a real fast process,” he said of the effort to get a marina.

The marina that once served the lake was removed several years ago when the maximum pool was not enough to sustain business. The license and much of the marina were shifted to Pine Flat Lake in Fresno County.

“It will take a year to go out to bid and find qualified folks,” said Foster, adding it will then take time to construct the marina.

“I would not expect someone this summer or next summer,” he said, although he has had inquiries from those interesting in operating a marina at Success Lake.

“I’d like to see it for the public,” he said of the marina.

Rick Elkins is editor of the Porterville Recorder. He can be reached at 784-5000, ext. 1040, or by email at relkins@portervillerecorder.com.