Planning for a new berm separating the J.W. Corbett Wildlife Management Area is well underway, and construction is scheduled to begin in March or April 2014, according to a South Florida Water Management District representative who gave a presentation at the Indian Trail Improvement District Board of Supervisors meeting Wednesday.
During heavy rains from Tropical Storm Isaac, water experts became concerned that the Corbett berm might breach, causing prolonged flooding in The Acreage. This led to $4 million in financing from the state to correct the situation.
SFWMD Division Director Jeff Kivett said he appreciated the help that has been provided by ITID staff to come up with a solution to the Corbett berm.
“I think we’re making great progress out there rebuilding the berm,” Kivett said, explaining that conceptual design alternatives have already been completed. “We got a survey out there, and we got geotechnical information, engineering calculations and modeling, and we’ve come up with two basic conceptual designs. We’ve pretty much honed in on a single one.”
Kivett said he still needs to sit down with ITID’s engineer to discuss the proposal.
“We want to get a buy-in from both sides, and at that point we will move into a final design,” he said. “We’re putting designs and specifications together for the contractor so the contractor can actually go out and construct it the way we want it. Engineering is the challenging part, but we’re very comfortable that we have procedures for that.”
Kivett said the existing berm has a steep design and sits right on the M-O Canal, which necessitates frequent maintenance and makes it vulnerable during storms.
“The stability that we’re looking for is to pull that bank quite a ways back so it becomes a very stable surface,” he said. “It will stay that way, we won’t have to go out there and it won’t be a big maintenance cost. Currently we’re looking at about an 80-foot swath of land that will be used to put the embankment in. There was a lot of discussion about environmental impacts, so we had our biologists out there looking at it.”
The other alternative was a sheet wall with an embankment on one side of it. “The cost seems to be a little bit prohibitive, and we’re worried a little bit about [the lack of] seepage during the dry season that we don’t cut off the water supply to the canal system [in The Acreage],” he said.
Kivett said his team is 95 percent sure the first option would be the one they go with.
The original estimate was that the environmental impact would be about 150 acres of wetland effects on the 30,000-acre Corbett area.
“It was very disturbing to everybody,” he said, especially to environmentalists. “Our first cut got it down to about 100 [acres]. We are now down to 17.4 acres of actual wetland impact. I think the mission we’re trying to accomplish here is something that is a reasonable amount of mitigation for residents.”
The planned berm will stop northward at the Mecca Farms site, where the SFWMD anticipates it will finalize its deal with Palm Beach County on the purchase of the land. “We will integrate that site into the movement of the Corbett water,” Kivett said. “It’s similar to today, where we still have the weir out there.”
During Tropical Storm Isaac, the SFWMD built an emergency weir to relieve rising water in Corbett so it would drain into the Mecca Farms property. This spring, rising water in Corbett had water flowing over the weir again. “The weir was flowing, and we actually flooded most of Mecca,” Kivett said. “We used pumps to transfer that water to the C-18 [Canal]. It worked again the way we expected it to when we put it in last year.”
That feature, although it won’t look exactly like the current weir, will be incorporated at that Mecca site, he said. “We will continue to have that control of the water flow over the Corbett,” Kivett said.
Kivett said they are looking at getting the construction package in March or April next year. “We should have all the permits at that point in time, and we will go into construction,” he said.
He added that there was discussion of doing some repairs there that had been approved, but he thought should not be done because of the cost.
“One of the things we’re interested in is trying to make sure that we don’t spend anybody’s funds, your funds, our funds, on something that isn’t needed or that will be removed at a later date,” Kivett said. “If we start to see some pressure on the berm, we will continue to send our engineers out like we did in May and June and do joint inspections to make sure we are all stable. If we do get into emergency repair, we still have our supply of materials sitting there on the Mecca site.”
He recommended the district start preserving its money to be used for construction. “We’re still looking at a $7 to $8 million construction cost for the full project,” he said. “Right now the legislature has given us $4 million, so we’re short of what we want.”
With the available money, Kivett said he expects to start with about 3.2 miles that needs to be addressed immediately.