In some of the most confident testimony yet as to the cause of severe cracking at Tampa Bay Water's six-year-old reservoir, HDR's expert witness Dr. Les Bromwell laid out in significant detail how isolated construction problems were to blame. The doctor's testimony came March 29, in the third week of the federal trial of Tampa Bay Water v. HDR Engineering.
Using numerous construction photos—all discovered after Tampa Bay Water initiated its lawsuit against HDR—an 8-ft-tall Gantt chart documenting the project's every detail, and a video depiction of his theory, Dr. Bromwell made the sometimes-emphatic case that poorly compacted sections deep in the reservoir embankment were leading to a situation where the soil would "collapse" upon becoming wet, essentially compacting and creating voids. Eventually, Dr. Bromwell testified, those voids would work their way to the surface, and cause the massive cracking that was occurring in two sections of the 15.5-billion-gallon reservoir.
Bromwell is a seasoned geotechnical engineer, with an expertise in soil-cement, which was used to build the Tampa reservoir. A graduate of and former professor at the Massachusetts Institute of Technology, Bromwell worked for NASA's Apollo program, where he helped plan lunar excursions and educated the agency and astronauts about the surface conditions of the moon, according to his court testimony. He also was the founder of BCI Engineers & Scientists, Lakeland, Fla., which advised on the earlier stages of the reservoir project. (The Lakeland firm is now AMEC Environment and Infrastructure, according to the company's website.) Bromwell was later hired by HDR as it was investigating the cracking for Tampa Bay Water.
Bromwell testified that he had first become familiar with the concept of "collapse upon wetting" in the 1960s on a couple of facilities he was involved with in Florida. Soils found in this area of the state are susceptible to this phenomenon if they become dry, he testified. He likened the issue to the soft sand at the upper, dryer portions of a beach and the more compact sand closer to the water that is more compact. Despite his familiarity with the concept, however, he, like others investigating the Tampa reservoir's cracking—including HDR—first thought that the cracking was due to excess pore pressure.
Tampa Bay Water is contending that excess pore pressure is the cause of the cracking, asserting improper design. Excess pore pressure within the soil, the theory goes, leads to water staying trapped within the embankment upon drawdown, which then leads to cracking. Design firms face unlimited liability in the state of Florida; TBW is seeking more than $90 million from HDR to fund a repair and expansion of the existing facility, which remains fully operational.
For nearly two years, TBW lawyers noted, the pore pressure theory was repeatedly cited as the leading suspect in the case of the mysterious cracking. But Bromwell couldn't make the puzzle pieces fit. If it was pore pressure, which would be an issue inherent to the entire reservoir, he wondered, why wasn't the cracking occurring around the entirety of the embankment? Also, if it really was pore pressure, the cracking should be occurring lower in the embankment, and not up high.
As he led the investigation, Bromwell began scouring every construction document possible, he testified. He documented every piece of equipment and every firm working the job, weather conditions, materials records and other information into a day-by-day documentation of the reservoir project's lifespan, resulting in the massive Gantt chart that was shown to the jury. And "That's when it finally all started to come together," Bromwell testified.
The chart showed, for instance, that one of the areas that experienced the cracking was constructed during an extremely dry period, the dryest on record for the project. The other section that experienced cracking had been the only area with the protective soil layer left uncovered when three hurricanes traversed the project in 2004, he noted. The heavy rains produced erosion gulleys that were repaired improperly, and this also caused the same poor compaction problem, Bromwell testified.
Shortly thereafter, newly discovered construction photos that had previously been the property of Barnard Construction—and not provided to HDR during its work investigating the cracking before it was fired by Tampa Bay Water—significantly added to his understanding, the doctor asserted. (TBW employee Amanda Rice's testimony regarding some of these photos was reported here.)
"It was a eureka moment," Dr. Bromwell testified. Did those photos make a difference in your understanding of the situation?, HDR attorney Wayne Mason asked him. After chuckling, Bromwell testified that the photos plainly showed improper placement techniques. He immediately thought upon viewing the images, "Look how thick that protective layer is."
Mason then led Dr. Bromwell through a dissection of several photos showing soil placement in the areas that eventually cracked, with the doctor asserting that in addition to being placed too thickly, the soil in one section was clearly too dry, and therefore too loose, when dozed into place. Citing the 8-ft Gantt chart, he testified that no water trucks were present on the project during that section's construction, and that the subcontractors documented the dry conditions. Weather data indicated this work—which was the first section placed—was done during the dryest period on record for the project. Overall, he said, this led him to believe that the soil did not have the optimum moisture content specified.
Asked about his confidence in his theory, Bromwell stated, "It's the only one that fits the facts."
HDR attorney Mason then asked Bromwell, "Is there any way it's pore pressure [that's causing the cracks]?"
"No," said Bromwell.
Dr. Bromwell's testimony was continuing on March 30. Tampa Bay Water had not yet started its cross-examination.