Jon Kennedy, TBW's reservoir renovation project manager, counters that cracking is much more extensive than HDR admits and that the engineer is entirely to blame.

"We've got cracking over two-thirds of the surface of this thing," he says. "We can't use this facility at its original intended capacity of flow rate until we get a permanent solution to this cracking."

Connolly acknowledges HDR has responsibility. "We've told TBW from Day One that we're going to be culpable, but let's find out what the real problem is," Connolly says. "TBW doesn't want to know the real [cause], because they see us as a checkbook to help fund their next project."

History

Barnard Construction Co., Bozeman, Mont., completed construction of the reservoir in March 2005, and the facility came on line in 2006. For a while, TBW, HDR and Barnard stood as proud partners of the new facility.

"It was a good job right after it was put into operation," says Kevin Ellerton, who was Barnard's construction manager and is now the firm's business development manager for dams and hydroelectric projects. "It was unfortunate what happened."

 

KENNEDY

In 1998, Tampa Bay Water hired HDR not only as engineer-of-record but also to provide site selection, soil testing and some construction oversight.

Built in Lithia, the reservoir is approximately two miles long, a mile wide and five miles in circumference—covering about 1,100 acres, according to TBW. The earthen embankment ranges from 32 ft to 75 ft in height and measures about 300 ft wide at its base.

Utility officials were still publicly praising the reservoir in 2007, nearly two years into its operation. That year, the region suffered significant drought, and the new reservoir proved its value.

The utility's then-director of operations, Ken Herd, told ENR Southeast, "The reservoir was extraordinary this year. It performed just as expected and provided us with surface water while we were experiencing a lack of rainfall" (Southeast Construction, ">11/07).

To meet demand, TBW drew down the reservoir to slightly more than two billion gallons by fall 2007. However, as early as December 2006, significant cracking began.

HDR had designed the reservoir's interior with a geomembrane layer at its base, followed by a section of compacted soil and then a 16-in.-thick flat-plate soil-cement liner at the upper level.

There was no drain system built into the soil-cement wedge. The specified normal drawdown rate of 66 mgd could be achieved by gravity draining, and the embankment's soil-cement layer would function, though both HDR and TBW knew it would crack.

Gerald J. Seeber, the utility's general manager, noted as much in a 2008 letter to nearby residents explaining why the reservoir was in no danger of collapse.