Blankets, mats, bonded fiber matrix, and mulch prepare the ground for vegetation.
By DeWitt Smith
It doesn’t matter whether it’s a department of transportation highway project; an expensive, designer golf course in the Caribbean; or just a run-of-the-mill seeding job—keeping soil under control is critical, and the effort to do so has created an enormous industry.
The industry, in this case, is that of erosion control mats and blankets. The point of these products is to prevent erosion, help seed germinate, and generally keep sediment, caused by movement of soil and water, to a minimum. The reason: to prevent water pollution, which the US government says causes $17 billion a year of onsite damage.
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Photo: Western Excelsior |
| Quick-degrading straw mats are ideal for temporary erosion control. |
The annual cost of fighting this is not cheap, and costs are put at $13 billion a year, according to the National Transportation Product Evaluation Program, based in Washington, DC. And a large part of this money is spent on blankets and mats, old but reliable forms of erosion control products.
The market has developed fast and evolved to include organic and biodegradable blankets and mats.
The Choices
Luke Snyder of Western Excelsior, a family-owned business in Evansville, IN, explains some of the choices available. Straw mats are made of wheat straw, which is used for temporary erosion control and degrades fairly quickly. Erosion control blankets, which range anywhere from 4 to 16 feet wide, are used to cover soil on slopes and for channel protection in low-risk, low-flow channels. Blankets or mats made of coir fiber—“they’re extended-term blankets made of coconut fiber,” he says—are engineered to handle moderate-flow and high-flow channels.
For severe slopes; streambanks; shorelines; and large, critical-flow channels, permanent turf reinforcement mats made of synthetic polypropylene are available.
Basically, it means the contractors have a great many choices to apply to the myriad problems that arise. No surprise that the problem dictates what product to use.
Installation in Northern Colorado
Casey Staley works for Hall-Irwin in Milliken, CO, an erosion control and pipeline company based in northern Colorado between Loveland and Longmont.
“I do all the installation of blankets and straw bales,” says Staley. “The terrain is rolling hills, not too bad, but the hills do cause a lot of problems with moisture, which runs right down the hill and takes the dirt with it. And of course, it gains speed as it goes,” he says.
The most prevalent type of erosion control job he handles is putting in blankets and wattles. The most challenging jobs, he says, are laying the blankets on steep slopes, which is very labor intensive.
“We went to Casper, Wyoming, to do erosion control for Wal-Mart,” Staley says. “There are two of them in Casper, and we did work on the new one. We were using a blanket that was 66 feet long, and we used 160 blankets, all on steep hills. The store was being built up on the hill, and we had to protect the soil down to the main road. From the top of the blanket down to the main road was at least 175 feet.”
The work was done in July, when it was dry and hot. One of the tasks was to cut the blankets, made by Greenfix America, to fit around the trees, which were part of the landscaping. The order was to leave the trees undamaged and standing. It was no easy task to cut slits into 66-foot blankets made of fiber to run around dozens of tree trunks.
“The job took two days of full work by six men, and that was pretty fast work,” Staley explains. “You had to make sure that you trenched in all the blankets 6 to 8 inches so that when the water runs down the hill it goes over the top of the blanket.
“When you’re working on an angle, you have to make sure you have an overlap with the next blanket,” he continues. “You start on the bottom and start up the hill, 6 inches along the top seam. You have to make sure all the blankets are overlapped so that the water runs on the top surface.”
Working on steep hills makes any job more time consuming, and there are some products on the market that help, such as rubber mallets and staples. And a new device has made putting down those big blankets easier.
“There’s a new product, a big staple gun, a Rifle staple gun M100, that makes it less labor intensive. We bought one this year, and you don’t even have to bend over,” Staley says.
The easier jobs, of course, are the front yards of houses being constructed. For that, the installers use one blanket, 8 feet wide, laid down in the winter after the landscaping’s done. When it snows, the ground is protected from erosion caused by the snowmelt.
Colorado, like so many other states these days, is very strict about enforcing erosion control regulations. “I understand the state EPA charges $1,000 a day for any violations and shuts you down until you fix the problem,” Staley says. “They don’t want sediment getting into the state waters.”
The Buzzword Is Green
Pete Stibich of Water Components in San Rafael, CA, talks about the changes he’s seen in the field of erosion control over the last decade. His customers, primarily construction companies, now have to pay attention to water discharge.
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Photo:
American Excelsior
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| An installation of Curlex excelsior blankets, which promote seed growth while protecting topsoil from erosion |
“Contractors are now responsible for any water discharges—waters going into creeks or anywhere—and the state EPA has tightened up the rules. Over the past 10 years, it’s gone from no controls to very strict guidelines, with the penalties becoming more severe. I’ve gone to plenty of these classes the water agencies put on. The days of sitting back and doing nothing are gone, not with $5,000-a-day fines,” says Stibich, who’s on the board of the Marin County Builders Association.
He adds that his customers, which also include municipalities, are more compliant with the regulations, such as Phase II of the National Pollutant Discharge Elimination System. That means the larger construction companies maintain erosion control year-round.
“The buzzword right now is green. The fiber that used to be wrapped in plastic now is wrapped in burlap so that it’s 100% environmentally friendly. That’s the direction we’re going in now,” Stibich says.
He also talks about photodegradable products, such as a blend of straw sandwiched between two plastic nets. The straw will degrade, and the sun will break down the netting over time. He carries blankets by North American Green, which are photodegradable and biodegradable. North American Green makes single- and double-net blankets, and he uses both depending on the needs of the job.
And he has no shortage of customers who prefer and use green products.
“The National Park Service and the Golden Gate Recreation Park [Golden Gate National Recreation Area] buy the biodegradable blankets from us. Same for Marin County,” Stibich says.
He adds that even though northern California is still coming out of a drought, he continues to move the erosion control products, such as the turf reinforcement mats made by North American Green and straw wattles from Western Fiber.
The Golf Course Specialist
Green has an entirely different meaning for Earl Martin of Sulphur Springs, TX, about 80 miles east of Dallas. Martin, who’s been in the erosion control business for 15 years, has a specialty: seeding golf courses. He also uses biodegradable products.
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Photo: Mat Inc. |
| Spraying bonded fiber matrix on a
roadside slope |
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Photo: Mat Inc. |
| The same roadside slope after bonded fiber matrix application |
“We’re a hydromulching company and work primarily on golf courses and athletic fields. We also do residential and commercial properties,” says the owner of L&E Services. “We use Soil Guard, a bonded fiber matrix, or BFM. You’re using your wood fibers that actually have the consistency more like hair. And they generate a nonwoven matrix, like a cotton ball.”
The key to the BFMs is the “glue” that holds all this fiber together, Martin explains. Once applied, Soil Guard becomes water insoluble, so it won’t dissolve with water.
The method he uses depends on the angle of slide or how steep the slope of the fields is.
“What’s going to affect the slopes is water runoff,” Martin says, and it doesn’t matter whether it’s from soccer fields, baseball fields, parks, or private and municipal properties. And then, of course, there’s his specialty, the golf courses.
“We’ve worked in Colorado, New Mexico, Nevada, and Arizona, and most of them are private courses. And we did one in Barbados, in the West Indies in 2001. We used lots of the Soil Guard on that golf course,” he says.
That golf course is the Green Monkey, a multimillion-dollar property designed by golf course architect Tom Fazio for the famed Sandy Lane resort. It’s located 1,600 miles southeast of Miami, a three-and-half-hour jet flight from there, on the easternmost island in the Caribbean. The distance added to the logistical puzzle on the project, because the only way to get equipment and supplies there for big jobs is to ship them in—no small feat.
“The soil primarily has a base of coral rock, and percolation is fantastic, meaning there’s a high volume of water. Being a Caribbean island, there’s lots of rain,” says Martin.
The rainy climate dictated some of the choices on the project. “Normally, topsoil goes on top of these golf courses, then your grass and seed go on top, and irrigation is used to get the grass going,” Martin says. “But this had 10-inch sand cap. It’s a layer of sand instead of topsoil, and the sand is round; it does not pack up. About the only thing flat on a golf course is a tee—everything else has movement on it, or a sloping move, because it’s got to have drainage.”
Martin says the job took six months. He had to ship in 260 tons—yes, tons; that translates to 520,000 pounds—of Soil Guard. Then he had to ship two 1,100-gallon Bowie hydromulch machines. He also shipped in course seeds and sprigs and zoysia grass, which is a warm-season grass native to China and Japan. Originally known as Manila grass, it was imported from the Philippines and introduced in the United States in 1911. The zoysia grass is also very salt tolerant, a good thing for an island sitting on the outer edge of the Caribbean and the Atlantic Ocean.
“Building this course was a big deal,” says Martin. “Three of the holes were in a rock quarry. The course was built over a two-year period, and I didn’t go in there until it was completed.”
The challenge, he says, was keeping the sand in place until the grass had a chance to get established. That’s why he used the Soil Guard.
The Martins (father and son; the L&E in the business name stands for Lance and Earl) have made a name for themselves doing golf courses.
“My son, Lance, goes to southeast Asia, to Thailand and Malaysia, building golf courses,” Martin says. “The Barbados project was interesting but not so difficult.”
He says there are other bonded fiber matrix products, some using cross-linked fibers. The product he uses was developed by Weyerhaeuser, which sold it to Mat Inc. in Floodwood, MN, in 1998.
“You must be certified in order to know how to put this product down,” Martin says. “It requires 3,000 pounds per acre, and all this is dry matter until it hits the hyrdromulch machines. You add the water, seed, and fertilizer and then apply it. We’ve put it down in lots of places, like in Vail [Colorado], at the Red Sky Golf Club.”
Red Sky is an exclusive, private residential club that has two designer courses: one by Tom Fazio, the other by Greg Norman. Martin was there to do work on the course and the multimillion-dollar homes.
“We used Soil Guard to hold some of the slope, and we took out some of the steep slopes, “ he says. “We have actually blown in on a vertical—like a vertical wall—and grown some grass on it. Now it’s got native grass and wildflowers, so it’s looking pretty coming out of these walls.”
Soil Guard is not just for very fancy golf courses. Martin says he has also used the product on department of transportation (DOT) projects and drainages, although it will not hold in the bottom of a creek bed, where there’s water.
One of his more challenging jobs is working on a Ruidoso, NM, golf course.
“We’ve got some one-to-one slopes we’re working with, very steep slopes. A one-to-one is approximately a 33-degree slope,” he explains. “We’re using wood-fiber mulch and increasing tackifiers. That’s glue—mostly a guar gum that’s all natural, all biodegradable—to hold the fiber mulch.”
Highway Landscaping Has Its Own Challenges
Bill Borger is vice president of Texas Environmental Management, a full-service erosion control company in Justin, TX. The company does a lot of highway jobs and new construction. With 18 years in the business, Borger has a lot of experience with the requirements of landscaping.
“Mostly what I do is new highway work,” he says. “And the most common problem during development is the stabilization of soil.”
Borger talks about the different methods he uses, from channel stabilizers to rock filter dams.
“You really can’t stop the water. You can only slow it down and hope it ponds and that gravity does its work to pull the sediments down,” he says.
His approach to fixing problems, including the type of seed he uses and the types of blankets or BFMs, varies depending on the season and site conditions.
“For instance, for temporary grasses we used German millet in the warm season. And we use a red winter wheat that’s a cool-season temporary grass. They’re all annuals,” Borger explains.
For the permanent stabilizers—permanent perennial grass—he tries to plant around February to April. With most everything being site specific, he says he has a lot of different tools in his belt.
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Photo: Mat Inc. |
| The type of seed and bonded fiber matrix used depends on the season and site conditions. |
“We like the BFMs, which you apply hydraulically. We mix it in a tank and then spray it out on the road. And if we add fertilizer and seed to the mix, it’s called homogeneous slurry,” Borger says.
Not every job calls for spraying, however. “For certain applications we’ll mix the seed, and other times, with the permanent grasses, we do the seedbed prep. Then we use mechanical methods and the cultipack seed drill,” he says. “Often, with the permaseed, we want an even coverage, and then we’ll cap it with a BFM if there’s a severe slope. Otherwise, we use wood or paper when the slope’s not so steep.”
Educating People About the Problem Is the Solution
It’s not just the doing that counts. It’s knowing how to do it right.
Enter John McCullah, a hydrologist, erosion control specialist, and Certified Professional in Erosion and Sediment Control (CPESC) since 1988.
In September, he taught a two-day course for California Department of Transportation (Caltrans) personnel from the department’s District 8.
“We spend a day in the classroom to teach about erosion control, and then we go into the field to test products,” McCullah said from a site in San Bernardino, about 60 miles east of Los Angeles, where he was taking a short break from his class of 25 professionals.
He described what he calls the big four soil stabilizers: straw mulch, hydromulch, erosion control blankets and mats, and compost. McCullah believes that’s the sign of the future.
“If you understood these four stabilizers, you could prevent 98% of the raindrop and sheet erosion on any construction site,” he says.
Caltrans is not his only client. McCullah takes his class on the road for a number of state departments of transportation.
“DOTs are now like landowners and have to comply with the Clean Water Act,” he says. “For many years they relied on the contractor to do the right thing. Now the landscape architects, resident engineers, and inspectors who work for [the DOTs] need a really good understanding about these BMPs and how they are applied and installed and need to be maintained.”
As far as McCullah’s concerned, if you don’t understand how the various BMPs work, you won’t be using them effectively: “You have something but not a best management practice,” he says.
McCullah lives in Redding, CA, and is president of a consulting business, Salix Applied Earthcare. He travels all over to teach about compliance and erosion control BMPs.
“I do this in Canada and in Kansas, Colorado, Oregon, Hawaii, and even Guam. Everybody’s trying to comply,” he says.
He not only is in great demand from DOTs but also puts his information out in several different formats, from books to 20-minute training videos. He developed and taught a two-week curriculum on landslide repair for the Province of British Columbia and coordinated the teaching between the Canadian Ministry of Forests and the Sechelt Indian Band.
McCullah believes in trying to get everybody on board to use the latest and same conservation practices, and he talks about these agendas at the International Erosion Control Association (IECA), of which he serves on the board of directors. He notes that his course, as well as others, will be offered at IECA’s annual conference in Orlando, FL, in February. “We’d also like people to know we can travel to your region and bring training to you if you can’t get to us.”
DeWitt Smith is an environmental features writer who lives in Ojai, CA.
EC - January/February 2008
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