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Reservoir Level To Drop For Inspection Of Cracks

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By MIKE SALINERO

The Tampa Tribune

Published: August 7, 2008

TAMPA - Tampa Bay Water officials plan to limit the amount of water stored this year in the C.W. Bill Young Regional Reservoir so engineers can better investigate cracks in the reservoir walls.

Tampa Bay Water General Manager Gerald Seeber said the level will be kept at about half the 15 billion gallon capacity. Next spring, during the dry season, 7 million to 8 million gallons will be drawn down, exposing cracks at the base of the walls that are now accessible only to divers.

"We're going to lower the level to allow the engineering team to look at that embankment from top to bottom," Seeber told Hillsborough County Commissioners on Wednesday.

The move to limit water storage this year - and essentially empty the reservoir next year - prompted commissioners to grill Seeber on how well the area could weather a drought and whether the cracks posed more danger than water officials had previously indicated.

"If I lived around there, I would have the life scared out of me," Commissioner Jim Norman said.

Seeber said there is no danger that the cracks, which are contained in the soil-cement covering on the inside of the reservoir, are compromising the reservoir's 240-feet-wide walls.

"We don't have any problem or notion of a breach at all," he said.

Lowering the water level will make the reservoir safer should a hurricane hit by protecting the walls from wave erosion, Seeber said.

The cracks started appearing in the reservoir walls more than a year ago and have worsened. Some are 6 inches wide and several inches deep and crawl along roughly 4 acres on the northeast and southwest corners of the reservoir.

Engineers have not figured out what caused the severe cracking. That riddle can be solved, Seeber said, and a solution devised once the cracks are exposed and engineers can take soil samples from inside the walls.

The reservoir now has about 6 billion gallons in it.

Seeber said emptying the reservoir is a gamble that could backfire if another drought hits the area like the one that ended this summer. The reservoir was constructed to store water when rainfall is heavy.

Tampa Bay Water diverts water from rivers to the reservoir when flows are high, a tactic intended to limit withdrawals from groundwater.

On July 26, the Southwest Florida Water Management District issued a water shortage emergency order allowing Tampa Bay Water to withdraw additional water from the Alafia River. But Seeber said the additional water will not be needed now that the reservoir is not going to be filled.

David Moore, executive director of Swiftmud, said the lost water from the reservoir shouldn't cause problems unless the area has a dry 2009 and 2010. Tampa Bay Water can get up to 90 million gallons per day from groundwater and additional water from the Hillsborough and Alafia rivers and the desalination plant, he said.

The loss of the reservoir's capacity, though, could affect when the once-weekly watering restrictions are loosened, Moore said. The restrictions had been extended until Sept. 30.

"Let me say this, this will be one of the issues that will be taken into consideration" when the water management board votes on whether to change the restrictions, Moore said.

In November, divers discovered that the soil-cement covering the interior walls is one-half foot or more thinner at the base than called for in the engineering specifications. Seeber said Tampa Bay Water will try to recover the costs of fixing the cracks from one or more companies involved in building and inspecting the reservoir, which is in southeast Hillsborough County.

Tampa Bay Water has spent about $700,000 fixing the cracks since early 2007, and has another $500,000 budgeted for the problem in the 2009 fiscal year budget.

Reporter Mike Salinero can be reached at (813) 259-8303 or msalinero@tampatrib.com.

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