Rain Exacerbates Reservoir's Problem With Cracks

The above-average rainfall of this summer is supposed to help fill Tampa Bay Water's C.W. Bill Young Reservoir in Hillsborough County.

Instead, it is posing problems.

The reservoir's soil-cement lining, which is designed to control erosion, is cracking. So are the patches.

"Rainwater gets in those cracks and causes erosion under the soil-cement, and that leads to even more damage than the original cracking," said independent engineer David Carrier. Carrier was hired by Florida's Department of Environmental Protection to monitor the safety and stability of the reservoir.

The dam is safe, Carrier said, but cracking in the soil-cement, also known as flat plate, is causing problems below the waterline on the northeast and southwest walls.

"I think the cracking of the flat plate and the movement of the flat plate down the slope has pushed and buckled up the material," Carrier said.

Carrier said it's important to continue patching cracks to prevent rain from causing more damage.

Tampa Bay Water has spent more than $700,000 patching cracks and has budgeted $500,000 for further work.

The reservoir was built 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 the need to draw water from diminishing underground supplies.

In August 2007, a News Channel 8 story revealed the reservoir had developed severe fractures, some measuring 300 feet in length. Tampa Bay Water insisted the cracks were a standard maintenance issue.

"A year ago they were telling us it was no big deal," said state Sen. Ronda Storms, whose 10th District is home to the reservoir. "Regular people knew that's not true."

"When you're standing there with fire hoses and pumping in concrete into gaps that are huge, that's a big deal," Storms said.

She says she recently was informed that Tampa Bay Water is considering two options for the reservoir. One is to continue pumping cement into the cracks. The other is to drain the reservoir and replace the problem soil-cement.

Tampa Bay Water says Storms is drawing a conclusion that no one else has drawn and is "absolutely incorrect at this point."