There are an estimated 1.2 million alligators living in Florida’s innumerable marshes, swamps, rivers and lakes. The hard-hat wearing divers working underwater for Cat customer Dickerson Florida Inc. on a canal job just north of here tried very hard every day not to think about that number as they waded into the deep, murky depths.
The $8.9 million slope stabilization project was part of the South Florida Water Management District’s ongoing effort to clean up Lake Okeechobee, the source of fresh water for 8.1 million Florida residents and the sensitive Everglades ecosystem.
Years of use, and damage inflicted in 2005 by Hurricane Wilma, had badly eroded the 60-year-old canal’s banks. The deterioration complicated efforts to move workers and material onto the bank to maintain the canal and – more importantly – it hurt water quality in Lake Okeechobee.
“When the banks erode like that, you deposit silt in the water,” says Howard Searcy, the South Florida Water Management District project manager who supervised Dickerson’s work on the canal.
“And that silt gets carried along until it gets to Lake Okeechobee, where it settles on the small organisms and small grass beds at the bottom of the food chain and everything starts dying. If the water going into Lake Okeechobee – or coming out of it – is dirty, it’s just not good for anybody.”
Previous efforts to stabilize the canal banks had attempted to re-establish the original shape of the waterway by backfilling the eroded slopes. But that approach was controversial because it required putting dirt in the canal water, compounding the murkiness officials sought to eliminate.
Working with the South Florida Water Management District, Dickerson, which had a long and award-winning track record as a road builder but was new to canal bank restoration, devised a novel approach to the problem.
Rather than try to restore the canal’s original contours, Dickerson reshaped the canal to conform to its eroded condition, making it wider and more useful during floods.
CATERPILLAR TECHNOLOGIES KEY
The work was tricky. The job site remote.
One-third of the 12-miles of canal bank Dickerson needed to regrade were completely underwater – and home to many curious, carnivorous alligators.
Divers would ultimately need to enter the water to install and secure turf-reinforcement mats on this extensive underwater portion of the job. And inspectors in diving suits would follow to make sure Dickerson performed the underwater worked to contract specifications.
The operators of the four hydraulic excavators doing the actual re-grading work faced a big challenge, too. They needed to “see underwater,” according to Larry Dale, the president of Dickerson Florida.
The solution: Caterpillar’s GPS-powered AccuGrade™ technology, which allowed the excavator operators to maintain consistent, to-spec grade even when they were working below the waterline and couldn’t see what they were doing. Combining digital design data, in-cab operator guidance features, and automatic bucket control, Cat AccuGrade Grade Control System allowed Dickerson to get it right the first time and to finish the 14-month job a month ahead of schedule.
"One more thing that made the job as successful as it was, was the GPS equipment that we had on the Cat equipment," Dale says.
“We saved a lot of money in survey and construction layout costs on land with it. And without it, it would have been very difficult to grade underwater to the tolerances we had. It essentially allowed us to see underwater.”
It also minimized the number of times inspectors had to re-enter the dangerous waters.
Jim Heimer, Dickerson’s equipment manager, says Cat dealer Kelly Tractor’s preventive maintenance monitoring of Dickerson’s equipment on the job using Cat Product Link™ technology also contributed to the project’s success.
“The distance from home base was one of the big challenges,” Heimer says. “But Product Link helped us out with that. It saved us a whole bunch of time. You already knew what the issue is, so you could go out there with the right parts and solve the problem.”
Heimer does much of the repair work on Dickerson equipment that is no longer under warranty. But he says “If I get into a pinch, I send it down to the shop. I say ‘the shop’ but I mean Kelly Tractor’s shop. Their shop is my shop. Kelly’s got my back.”
“We had little to no downtime. And this is in an isolated area. To get a mechanic out there from our office would have taken two, three hours each way.”
Nearly two years after the project wrapped up, officials with South Florida Water Management District say they’re very happy with the work. “Dickerson did a fantastic job,” says Searcy. “We’ve had a number of significant rainfall events since the work was completed and we have not had one issue with erosion. The slopes are more stable. And the canal is now able to convey more water.”