Work on the average construction site disrupts many cubic yards of dirt. All of that disrupted soil poses a big sediment control challenge. Given the unpredictability of storms and rainfall, controlling sediment requires vigilance. It also adds to the cost of construction projects. But if sedimentation is not controlled, the cost is even higher: potential fines from state and federal regulatory agencies and damage to the environment.
Fortunately there are some very effective strategies and products to help manage sediment on construction sites. Containment
—a classic military strategy—is the first line of defense for sediment control on construction projects.
One of the most common ways to do containment is by installing an effective control all around the perimeter of the site. A silt fence or a similar, but improved, product will hold soil and sediment on the inside of the perimeter, but allow runoff to flow through.
RIPA & Associates, a Florida based company doing erosion control work, follows that strategy. Here is a story behind one of their interesting projects.
Bexley Ranch
“We’re passionate about the outdoors and protecting the natural environment,” says Grayson McCormick, environmental compliance supervisor for RIPA & Associates, the largest construction firm in Tampa, FL, with 650 employees.
McCormick leads RIPA’s Environmental Division. In the last 12 years it has grown from six to 30 employees.
“I take a lot of pride in the fact that RIPA is without a doubt a leader in environmental compliance. We spend millions on environmental compliance. We do it because it’s the right thing to do,” he explains.
With 81 active job sites, RIPA’s Environmental Division has three crews that “do nothing but repair and maintain silt fences,” says McCormick. “I’d say that about 70 of those jobs have Silt-Saver products on them.”
One of those jobs is the Bexley Ranch project near Tampa. The thousands of acres of land had been held by several generations of the Bexley family since the late 1940s.
Because the area is environmentally sensitive, it took years before the Florida Department of Environmental Protection and other agencies granted the required permits to allow development. A condition for development was the preservation of part of the land as a natural habitat for wildlife.
It will take 10 years or more to develop this master-planned community. The land sits at the headwaters of the Anclote River, where the water is pristine and wetlands abound, requiring extra effort to protect the environment.
“The quality of the wetlands is great. It’s totally undisturbed land. The most unpolluted water in the entire river is here, at its source,” says McCormick.
The Bexley Ranch development will be done in sections. RIPA began clearing the first section of the land—a bit more than 300 acres—in October 2015.
“Perimeter control protecting the wetlands from runoff from the job site is critical. We’ve got 70,000 linear-feet of silt fence for perimeter control. Of that, a solid 75% is adjacent to wetlands. Everywhere you look there is surface water and wetlands,” says McCormick.
“On our job sites, to be in compliance you have to use products that are better than the industry standards,” he explains.
McCormick and his hard-working crewmembers rely on Belted Silt Retention Fence (BSRF) from Silt-Saver of Conyers, GA. “It costs three or four times what regular silt fence costs. Some of it costs 10 times as much, but it’s worth it,” he notes. “With the conditions we work in, as sensitive as these areas are, we don’t have a lot of room for error.”
Developing the Bexley Ranch land is “basically developing a floodplain,” he says. “In summer, 75% of what we’re developing would be knee-deep in water, so a lot of fill has to be added, and there’s a lot of rerouting of surface water.
“Ten feet on the other side of the silt fence is water and cypress trees. A lot of the land is under the Army Corps of Engineers’ jurisdiction. Runoff from it flows right into the river, not into a tributary or a ditch. That’s a big deal,” he notes.
Adding to the challenge of working in the sensitive wetlands of Bexley Ranch is Tampa’s weather. McCormick says this part of Florida is one of the rainiest.
“We average 67 inches of rain per year, so stormwater is a big deal for us. In summer, we get one inch of rain almost every afternoon, the most intense type of rain. That’s 30 acres of sheet flow coming at the Silt-Saver fence.”
He adds, “One row of BSRF is worth three rows of regular-grade DOT silt fence. I’ve seen it have dirt to the top—two or three feet of dirt—and still hold it [during a heavy rain]. Even with a double row of regular silt fence, you’d have dirt going over the top and 50 feet into the wetlands.”
Bexley Ranch in Tampa, FL
McCormick terms Silt-Saver’s BSRF “a superior product. If it works with what we do, it’ll work for anybody.”
Finding a product that works under challenging weather and environmentally sensitive conditions makes good business sense. If sediment and dirt pollute pristine waters, like those in the Anclote River’s headwaters, he says, “you can rack up 50, 60, 100,000 dollars’ worth of fines. If a job site is shut down, that’s millions the company would lose.”
If there were a break in the construction site’s perimeter that sends sediment into the river, RIPA & Associates would be required to clean it up at its own expense. The cost would be quite high.
“We couldn’t use machinery. We’d have to have 20 guys with wheelbarrows and shovels. Using the BSRF pays for itself very quickly,” he says.
Despite the challenges of sudden heavy rainstorms on an almost daily basis and working in a highly sensitive environment that has so much surface and groundwater, McCormick believes his team will succeed on this unique project. The basis for his confidence is their experience coupled with the water management plan.
“Having an effective water management plan for your construction site is absolutely critical to the success of the job, not just for environmental compliance, but in getting the work done on time, and on budget,” he says. “And water is your number one enemy if you’re building on dirt—surface water from storms and groundwater coming out when you excavate.”
In practical terms, “a water management plan saves money. With one, we build the job faster and make more money because we get through sooner,” he notes.
“Before we start a job, we deal with all of the water on the site. We put in all the pipes and culverts to manage the water, so we can do the work and we’re not creating pollution,” explains McCormick.
As for environmental compliance on water-quality issues, McCormick says, “If you have a water management plan and have a sequence [for the work], nine times out of 10, the inspectors will say ‘OK.'”
He cautions, “You have to minimize the environmental impact as much as possible, but there is no way for nothing to ever go wrong.”
If something does go wrong, RIPA’s policy is to “do something better the next time. You have to elevate that BMP, as the general construction permit says.”
Inspectors are a strong presence on such a sensitive site as the Bexley Ranch development. McCormick says they’re from the city of Tampa, Pasco County (“It has jurisdiction there and a strict stormwater policy”), the Florida Department of Environmental Protection, the Army Corps of Engineers, and the Southwest Florida Water Management District.
“We see them very regularly. Every other week or so some regulator is here, or I get a phone call,” he says. Two full-time company inspectors check the site’s perimeter “after every half-inch of rainfall, per our permit.”