By Craig Pittman, Times Staff Writer
Posted: Aug 15, 2011 10:27 AM

CLEARWATER — Despite their misgivings about the impact on their rates, Tampa Bay Water’s board voted unanimously Monday to sign a $156 million contract to fix its cracked reservoir and expand it from 15.5 billion gallons to 18.5 billion gallons.

The construction work by a Nebraska-based firm, Kiewit Infrastructure Group, is now scheduled to begin late next summer, with completion in 2014. The work will require draining the reservoir and instead relying on the utility’s other water sources, such as the frequently troubled desalination plant, which produces the most expensive water in the regional system.

One board member, Hillsborough County Commissioner Sandy Murman, said she supported fixing the reservoir but worried about the impact on the rates. Tampa Bay Water provides wholesale water to utilities in Pinellas, Pasco and Hillsborough counties, which pass along any rate increase to their customers.

“We’ve had a series of bad results from big projects,” Murman said. “I want to cross all the T’s and dot all the i’s so we have a smooth landing on this. But I think we’re taking the cart before the horse.”

Murman said she worried about proceeding with the repairs of the reservoir before a trial next month of the utility’s lawsuit against HDR Engineering over the cause of the cracks. Tampa Bay Water contends HDR’s design of the reservoir was flawed, while HDR points the finger at the company that handled construction.

The utility’s finance director, Koni Cassini, told Murman that the worst-case scenario would require a 10 to 15 cents per 1,000 gallon rate hike — but if that happened, she said, she would spread the increase over several years to lessen the sting.

The board voted in June to raise its rates 3 cents a month per 1,000 gallons of water used, or just under a quarter for the typical user of 8,000 gallons a month. The increase is to cover the cost of running the desalination plant harder than usual during the two years when the reservoir is being repaired. That will require spending more on power and chemicals for the desal plant.

In addition to the $156 million for the repair and expansion, Tampa Bay Water is putting aside about $6 million to cover any unforeseen expenses during work, which is expected to be completed in 2014.

In addition to hoping to recoup some of the costs of the work from its lawsuit against HDR, Tampa Bay Water’s board is asking the Southwest Florida Water Management District to cover half the cost. But that state agency is facing a 36 percent budget cut mandated by Gov. Rick Scott and the state Legislature.

The utility opened the $144 million C.W. Bill Young Regional Reservoir in June 2005 to store water skimmed from the Alafia River, Hillsborough River and Tampa Bypass Canal. The reservoir, named for the longtime congressman from Pinellas County, covers about 1,100 acres in Hillsborough County.

The reservoir’s walls consist of an earthen embankment as wide as a football field at its base, averaging about 50 feet high. An impermeable membrane buried in the embankment prevents leaks.

The embankment’s top layer, a mixture of soil and cement to prevent erosion, began cracking in December 2006. Some cracks were up to 400 feet long and up to 15½ inches deep. Workers patched the cracks, but the patches didn’t last.

An investigation found water is getting trapped between the soil-cement lining and the membrane. As long as the reservoir is full, the trapped water remains stable. When the utility draws down the reservoir, though, pressure increases on trapped water in some areas, producing cracks and soil erosion.

The cracks have not been deemed a safety hazard to the structure, but utility officials say if they don’t fix their underlying cause then conditions could get worse. But HDR officials contend the problem is not that serious, and could be solved with a simple monitoring and maintenance program that would cost less than $1 million a year.

Kiewit’s proposal called for digging out and replacing the soil cement and the membrane beneath it. The reason, Kiewit’s design manager, Trent Dreese, said earlier this year is that they believe the cracks showed a weakening of the reservoir wall and “additional failures are likely during drawdown” of the water for the repair.

As for the expansion, Kennedy said the only change that would be visible was that the walls would be about 10 feet higher.