Utility Calls Reservoir Cracks, Patches Routine

By NEIL JOHNSON The Tampa Tribune

Published: Aug 29, 2007

TAMPA - Scores of jagged cracks of varying sizes have opened up along the cementlike material covering the walls of Tampa Bay Water's massive reservoir in southern Hillsborough County.

Crews have been working for three months to fill the fissures with grout to keep them from enlarging when rainfall eventually causes the water level to rise.

Alarmed by the cracks, state Sen. Ronda Storms, R-Brandon, asked the state to inspect the reservoir and determine whether the cracks posed a hazard.

On Tuesday, two inspectors from the state Department of Environmental Protection's Tampa office went to the reservoir and said they found no threat.

"There is no compromise to the structure," DEP spokeswoman Pam Vazquez said.

But Storms, a former member of Tampa Bay Water's board, questioned why anyone would accept cracks in the walls of a reservoir designed to hold 15 billion gallons of water.

"Nobody expects a reservoir to have cracks," she told WFLA, Channel 8. Storms said she intends to ask the governor's office to investigate.

The cracks run through the soil-and-cement mixture that acts as a facing on the reservoir walls and guards against waves eroding the earthen embankment.

Designers said Tuesday that they expected the cracks and that the fissures do not threaten the reservoir's safety.

"The cracks were anticipated," said Barry Meyer of HDR Engineering, one of the reservoir's designers. "There are no issues with the structural integrity."

The cracks are mainly in the northeast and southwest walls of the reservoir.

The soil-and-cement mixture is meant to keep waves from eroding the earth behind it that makes up the embankment. A heavy, impervious membrane buried in the embankment behind the soil and cement prevents water from leaking. The embankment is 360 feet wide at its base.

Vazquez said monthly inspections for the DEP conducted by a private engineer paid for by Tampa Bay Water have found no problems since the reservoir opened.

The soil-and-cement mixture commonly is used to prevent erosion for embankments and dikes, and cracking is not unusual, said Joseph J. Kulikowski, president and principal engineer for Genterra Consultants, based in California.

The company designs and does consulting for dams and reservoirs and was not involved in the Tampa Bay Water reservoir project. Without seeing the reservoir, Kulikowski said he could not say whether the cracks endangered the reservoir.

Tampa Bay Water, which provides wholesale water for public utilities in Hillsborough, Pinellas and Pasco counties and Tampa, St. Petersburg and New Port Richey, built the C.W. Bill Young Regional Reservoir in 2005.

It was intended to store water from rivers during the rainy season and can provide more than 60 million gallons a day during the dry season.

A drought and lack of water from rivers caused the utility to nearly drain the reservoir last winter and spring. In July, the reservoir had dropped to about 2.5 billion gallons, its lowest level since opening.

Recent rains and permission to draw more water from rivers have raised the reservoir to about 5 billion gallons.

The low water level exposed the walls and cracks. This is the first time cracks have been filled, and work should be finished by the end of September.

Amanda Rice, the project engineer for Tampa Bay Water, said the work was considered routine maintenance.

It will cost about $200,000 from the $500,000 earmarked for general reservoir maintenance.

News Channel 8 producer Steve Andrews contributed to this report. Reporter Neil Johnson can be reached at (813) 259-7731 or njohnson@tampatrib.com.