In every construction project, the dirt is the “X factor,” and companies that construct buildings can build several of the same kind of structures, notes Mike Christofferson.
“But every place you build is going to be a little bit different as far as layout and what’s around it,” says Christofferson, president of Silver Leaf SWPPP, a turnkey erosion and sediment control company in Salt Lake City, UT, that provides services to contractors in engineering, installation, maintenance, and inspection.
Adherence to the SWPPP-or stormwater pollution prevention plan-is critical in ensuring that erosion and sediment control and stormwater management on a construction site is maintained both during and after construction.
Silt fence and wattles are the two most commonly used best management practices (BMPs). A wattle is typically a berm- or burrito-shaped product that can be constructed of natural fiber such as rice straw or coir, or that consists of geosynthetic fabric covering some sort of filtration material such as compost, plastic pellets, and ground rubber tires, among other fillings. Wattles are often used in channels in place of traditional rock check dams.
Christofferson, like other contractors, seeks a form of sediment control that not only does the job in terms of keeping sediment at bay, but also looks good while doing it.
“A lot of times with silt fence, when you’re on a tight site, guys will drop steel and other things on it, they run it over, and it looks terrible,” Christofferson points out.
The success of his company’s operations depends on using quality products, says Christofferson. Silver Leaf SWPPP uses Gator Guard wattles as a BMP.
The wattles are made in the United States with recycled foam and UV-resistant geotextile, featuring an apron that minimizes underflow washouts. They are designed to be lightweight, provide 20 times less soil loss than straw wattles, and are easy to maintain and remove.
Christofferson favors them on projects in downtown Salt Lake City or at Brigham Young University, where there is a lot of traffic and high visibility.
“We found that the Gator Guard has been a really good solution as a BMP in several of those situations,” he says. “It not only works well to help with the sediment control, but it’s also very durable. We use it on projects that are going to last two or three years, and we’ve never had issues with it.”
One recent project occurred on the campus of Brigham Young University, where several large contractor firms from throughout the state have been working on new housing projects. Silver Leaf SWPPP has been doing the erosion and sediment control work for most of the general contractors on the site.
“Because it’s a college campus, the site itself is very tight,” notes Christofferson. “There’s not a lot of room for a laydown yard, so it’s very high-profile there on campus. You’ve got a lot of people watching it. The last thing we want to do is have a dirty site, a site that looks like there’s nobody who cares. A lot of time that happens with silt fence.
“If somebody laid a pallet of some of their electrical supplies on the Gator Guard, we knew the Gator Guard would still perform well after they picked up the pallet,” he says.
Throughout the two-year project, Silver Leaf SWPPP has never had to replace a section of Gator Guard.
The wattles not only provide sediment control, but also demonstrate good housekeeping, Christofferson says. “If a city inspector drives by the job site randomly and he sees the silt fence or whatever BMP you have in place all beat up, he’ll make you stop,” he says. “But if he drives by and sees the perimeter control is in good shape, a lot of times they don’t.”
One of the challenges with the BMP is that it has low visibility compared with silt fence.
“Sometimes guys will run over it in a truck, but it’s durable-it just fluffs back up,” says Christofferson. “There are the challenges of contractors having to move your BMPs, but that’s pretty typical on any project.”
Christofferson also likes the wattles’ ability to be used on more than one project. “If you’ve got a job that’s only three to six months or even longer, you can take it from one job site to the next and reuse it,” he says. “That’s been a big thing for a lot of our excavators. They like for us to use that product on more than one job site because on the next job site, they can just take it off. They like they’re paying for materials just once.”
A California Transfer Station
In southern California, Rodrigo Huerto, an operations manager for a transfer station, uses Filtrexx sediment control to help him keep compliant with stormwater programs. He has to sample twice a year for the programs, tracking oil and grease, metals, pH, and total suspended solids.
Filtrexx manufactures compost-filled wattle tubes and other compost-related products that can be used as sediment barriers. They can be used as temporary dry pond sediment containment detention systems to capture sediment and settle suspended solids in runoff from disturbed soils. They also are used to settle suspended solids from detention pond outfalls or potential overflows. They can be converted to or retrofitted for post-construction stormwater quality detention systems.”
Because their installation requires no trenching-they can be installed in any soil into which stakes can be driven-no major excavation, land disturbance, or pond construction is necessary. The filler material-the organic matter and humus colloids-bind and adsorb phosphorus, metals, and hydrocarbons that may be in stormwater runoff. The filter media also can degrade organic pollutants and cycle captured nutrients in stormwater runoff.
Huerto used to use gravel bags in the past but, about a year ago, switched to the Filtrexx product.
“It’s a filter fabric,” he says. “It does a better job. It’s got rock in it as well. I notice that the water after a rain event comes through clear. In addition to that, we have traffic here that sometimes leaves some diesel and gas on the asphalt, and this helps a lot when it comes to that.”
Huerto uses the Filtrexx to protect the storm drains and provide erosion control as well. After major rain events, he notices that there is hardly any silt or mud in the storm drains.
Adherence to the SWPPP is critical in ensuring that erosion control is maintained both during and after construction.
The product also is affordable, Huerto says. “You don’t have to spend a lot of money, because you don’t have to replace them as often,” he says. “It’s been over a year and they’re still good. The regular bags break down, then you have to pay for labor to take them out and you have to pay for the disposal as well and replace them. I used to replace gravel bags two to four times a year.”
He notes, “When I first heard about them, I didn’t think I’d have any use for them,” adding that he met with a company representative to do more research. “A lot of agencies are backing up this BMP, so I was willing to give it a try. I am happy I did, because I don’t have to spend much time cleaning them out and doing extra work. You can put them just about anywhere-they’re so easy to install.”
Maintaining for Durability
In its day-to-day provision of BMPs on construction sites, Engineered Fabric Specialists (EFS), an erosion control distribution and installation company in Norcross, GA, uses a variety of sediment control devices. Among them are products by Erosion Tech, which manufactures a full line of erosion control and environmental products, including silt fence, in Juliette, GA.
“They’re a local company, and we have a good relationship with them. We’ve found that their products always meet the highest quality standards,” notes EFS president Billy Egan.
That’s important to Egan, whose company provides all means of erosion control for ground-disturbing projects, including the installation, maintenance, and final stabilization.
“The benefit of the silt fence is that it works well within a system with other products,” points out Egan. “People have gotten away from the idea that they could wrap the perimeter of a project with a silt fence and leave it alone and everything else will take care of itself. Over time, we’ve all been educated that it takes a system to control erosion properly for preventing sedimentation.”
The system entails a combination of BMPs, including inlet controls, silt fence on the perimeter, the grading operation being phased properly, the ponds being built on the job and sized correctly, and the controlled use of water.
“All of those things are part of a system that will eventually make a project successful,” Egan adds.
Egan favors the versatility of Erosion Tech’s silt fence, as it can be used in a variety of applications, such as when the crews are moving dirt from one side of a project to another to make the grade. “A lot of times we use a double row to reinforce the area for adequate protection to keep the sediment from leaving the job site,” he notes.
A silt fence is one of the more cost-effective items to use on a construction project for sediment control “as long as it’s used in conjunction with other products and best management practices to create an overall system,” Egan points out.
“I think sometimes there’s the idea that it’s a relatively inexpensive item and you can put it up and get away with protection for the duration of the job,” he adds. “Truly, it’s most effective when it’s installed in the right application and-when the sediment starts to fill up at the fence-it’s maintained properly.”
Installation Is Key
Often, the machines used to install sediment control BMPs are just as key to the success of the project as the sediment control materials themselves.
Dave Lange, owner of Lange Nursery and Landscape in Hills City, MN, is frequently called upon by general contractors to provide erosion control for municipal projects, such as the construction of roads, sewer lines, or walking trails. Such erosion control encompasses silt fence or wattles, and his company also might blow straw, hydroseed, or provide blankets for the site.
Until recently, he’d install silt fence by trenching. Having heard about the tommy Silt Fence Machine from others, though, Lange had always wanted to own one and recently purchased one with which he’s now installed more than 20,000 feet of silt fence.
As Devon Distributing, manufacturer of the tommy Silt Fence Machine, points out, trenching involves extra crewmembers, work stoppage in wet weather or rocky soil conditions, slow and costly dirt removal, and cumbersome backfill and compaction. In contrast, the machine enables contractors to slice through the soil, condition it for future compaction, and smoothly insert silt fence fabric 8 to 12 inches deep. It also can turn to maneuver around construction site obstacles
“This is probably six times more efficient,” Lange says. “You don’t disturb much soil, you have better contact, and it’s a lot quicker and easier.”
The learning curve is quick as well, with attachment simple to run, he says, adding that it’s been a savings in labor and time.During one of Lange’s projects, a representative of the Minnesota Pollution Control Agency was on the job the day he was using the tommy Silt Fence Machine. “They were very happy with the product and what it was doing,” he notes.