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On the bench or in the field, EC blankets and mats are put to the test.
By Janis Keating
“Trouble is only opportunity in work clothes,” industrialist Henry J. Kaiser once quipped. In erosion control, work clothes are the attire when attending to the “opportunity” of removing troublesome, failed products and installing new ones. There are a variety of reasons why an item might not perform to expectations—maybe it wasn’t the right product for the job, the weather might have been too much for it to handle, or installation might not have been top-notch—but the results are the same: costly rework.
Avoiding rework by choosing the right product the first time isn’t always simple: Does an item really perform as advertised? What’s the manufacturer’s definition of “heavy storm”—a 10-year storm? 50 years? 100 years? What product would work best for your application and the site’s soil type—straw or coir? How can one compare the two different ingredients? What about the differences in netting? Even if you had the time to thoroughly research all the items you want to buy, is your comparison apples to apples, or apples to oranges?
With such questions in mind, the Erosion Control Technology Council (ECTC) is developing guidelines and standards for rolled erosion control products. Products will be tested and rated so purchase decisions can more easily be made.
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Photo: D2 Land & Water Resource |
| A vegetated coir log staked in place (prior to being lashed with rope) at the
proposed waterline over a turf reinforcement mat. |
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Photo: D2 Land & Water Resource |
| The more-complete installation. A mat laid on the bottom of the waterway
helped installers stay out of the mud while working. |
“Our program is called QDOR—Quality Data Oversight and Review,” says ECTC’s executive director, Laurie Honnigford. “Our task is to standardize the testing protocol for rolled erosion control products. In the past, competing testing protocols have led to confusion and discontinuity in the quantification of performance data for these products.”
ECTC is currently in the final stages of establishing an oversight committee that will review material performance data and index property testing and conformance in the QDOR process.
“There’s already a rolled testing plan in place,” Honnigford says. “The National Transportation Product Evaluation program, which is a part of the American Association of Highway Transportation Officials [AASHTO], tests products, but that’s bench testing, prototype testing; we need to test ‘real-world’ forces. For example, eroding soil picks up more velocity as it goes down a hill; no ASTM lab could duplicate that force on a bench. However, now we have a test method for rainfall or large-scale channelized flow, which meets standards 6459 and 6460. There will be a dedicated site for real-world testing—we want to move the testing for the whole industry.”
She stresses the testing’s bottom line. “The biggest issue is, how long does a product last in the field? Straw degrades relatively quickly; coir lasts a lot longer, maybe two years, where straw is gone in one season for the most part. Of course, though, different applications may require different product longevity.
“When comparing similar items, we want to standardize how we get the test results. To date, all other testing has been done to the manufacturers’ standards, and their processes aren’t all the same: different testing, different numbers, different channels, different heads on the rainfall applicator. Manufacturers will test their items to put them in the best light. We want standards—if a product does stand up to a certain water velocity, we will rate it as such.”
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Photo: D2 Land & Water Resource |
| The more-complete installation. A mat laid on the bottom of the waterway helped installers stay out of the mud while working. |
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Photo: Rhino Seed & Turf Supply |
| The Thanksgiving snow halted further work on this commercial project, but the site remained intact. |
Perhaps a product’s construction is what causes it to fail; ECTC intends to address that issue, as well. “We’ve planned a quality control [QC] program,” Honnigford says. “Some of the smaller EC product players don’t have a QC program. From time to time, we get complaint calls from various states’ departments of transportation [DOT]—‘We got things on site with holes in it’—and, after questioning them, we discover their supplier isn’t an ECTC member. We can handle members who have agreed to certain standards, but not non-members.”
Right now, state DOTs are over a barrel. “They’re required to take the lowest bid; however, if the product purchased doesn’t perform and has to be replaced, does it remain the lowest bid? Little firms might say, ‘The weight of my blanket is the same as those from the big time companies; it looks the same, it must be the same.’ But until it’s tested as such, it isn’t the same. After our testing program is in place, state DOTs can take the lowest qualified bid—the product specifications will perform as stated.”
When the program gets fully underway, there will be testing plots across the nation. Manufacturers will be able to choose one of the authorized labs that will do the testing for ASTM compliancy. “We have four labs right now, others are working in that direction now that we have a standard. TRI/ Environmental has a lab in South Carolina; Erosion Lab is located in Rice Lake, WI; and Dr. Thornton’s lab at Colorado State is also involved. We only have so much capacity in our lab as we get up to speed. Testing takes a long time—especially to find out the longevity of a product.”
Honnigford explains how the testing procedure might begin. “If we partner with AASHTO, a DOT representative from your state will visit your plant to choose the materials for testing. He’ll pick rolled products at random, which you must then send in for testing. If those random products pass the testing protocol, you’ll get a sticker for the product, which will announce that you’re QDOR compliant, and you can display the QDOR logo on your letterhead. Manufacturers will not have to be an ECTC member to participate in this testing process. However, ECTC members will have their products listed on the application selection Web site tool.”
As the testing program is meant to raise industry standards, it will be modified when there are changes in the industry and the approved products will need to conform to changes in standards of practice. At present, the QDOR program is targeted to rolled erosion control products, but ECTC expects to have similar programs for hydraulically applied erosion control products and sediment retention fiber rolls in the near future.
The QDOR program is definitely proactive. “We’re second guessing, as government standards are moving toward performance,” Honnigford concludes. “We want to be ready if the EPA demands a certain product performance level. Erosion control is crucial to our nation’s future. We need to keep our soil where it belongs, and have to take care of our water. The ‘next war’ will fought over water, not oil.”
“Tested” Every Day in the Field
Of course, although it’s not under laboratory conditions, EC blankets are “tested” on real-life projects everyday. Products that live up to expectations get repeat business; brands that fail on the job aren’t purchased a second time.
North of Indianapolis, IN, D2 Land & Water Resource’s Jim Blazek finds North American Green’s products work well for his applications. A project named Campbell’s Ditch offers a typical scenario.
“In the late 1990s, Indiana did lot of county bridge replacements,” Blazek says. “Sometimes it’s necessary to realign the legal drains that flow beneath. We used to make straight uniform ditches, but the permitting agencies, such as the Department of Natural Resources, now want to see them with more natural features—native plants, some rocks. They weren’t happy if they just saw riprap on banks; they wanted vegetation to develop quickly, away from the water, to a buffer of native plants. For Campbell’s Ditch, the designer, Mike Obergfell, P.E., of USI Consultants Inc., called me and asked, ‘Didn’t you say you could get plants to grow with rocks?’”
Blazek indeed had a solution. “We used coir logs and North American Green’s SC250 turf reinforcement mats [TRMs]. At the time, it was a new construction detail, putting a turf mat right next to rocks or native water. About 16 years ago, I’d started using coir logs as a transition piece from water to land. The logs encourage sediment deposition right at the rock line, offering a soil area for plants to take hold. Since the water levels in some of these ditches can be high for weeks or even months, you need something sturdy there, and coir logs give you about seven years of life. This time-tested arrangement of materials allows me to give designers, like Mike, the specifications—‘These plants go from point A to point B, atop coir reinforcement mat.’ When you put a vegetative coir log in, you can do so during all times of the year, and you don’t need an educated staff to put it in. Logs and blankets can be placed at the edge of live water, to where you want vegetation.”
Anchoring the transition zone is crucial. “It’s guaranteed native plants will be established, if you pick the right plants,” Blazek says. “A lot of times, these projects are public low-bid jobs—using a process that works well gives a consultant better ways of getting a permit. Agencies are happy, because the result is more natural, and it’s a way to hold the specifications, because putting in our type of transition zone is specific—what staking pattern to use, and which vegetation is put in. People can’t ‘cheap’ the specifications, which gives the consultant confidence. No matter who gets the bid, it can’t fail.
“This is much better than the old way—just putting rock everywhere,” Blazek continues. “Our technique not only looks better, but it’s often at the same cost, or less expensive, than just putting rock in. Having the vegetation right there is better for the water, and native plants root deep, so the soil is secure.”
For Campbell’s Ditch, roughly two-thirds of a mile of banks was given “the treatment.” “I’d say it was about 2,000 feet on both banks, or about 4,000 feet of coir logs and blankets. We edged the ditch with coir logs, which were staked and lashed with rope. A strip of SC250 blankets about 14 feet wide was placed above the logs. No rocks were used in this job. People like rocks; I tell them: ‘Go ahead and use them, but switch to native vegetation.’
“When the water level rises, by placing a log atop a turf mat, sediment gets dropped out. We use a high-density log, with an extremely durable net—you can’t break it. Coir logs have the resistance of a 24-inch rock. The logs allow for the many years it takes for plants to establish, but when they do get established, they’ll move up the bank.”
Blazek uses coir logs from various manufacturers. “I’ve used vegetative coir logs, those with polypropylene net, some with 9-pounds-per-cubic-foot density. In the early ’90s I got freaked with coir logs, because I couldn’t get blankets installed properly—grass wasn’t growing at the water line, ducks would eat the seeds, and if you got a high water velocity, blankets wouldn’t work. Coir is expensive, but I never have to worry about it.”
With its amazing water-retention ability, coir not only keeps plants moist, enhancing germination, but the weight of the held water also helps to keep the log in place. “One year I took a trailer of logs from Indiana to Nebraska, in 98 degree heat in open truck, and they kept cool and wet,” he recalls. “You can’t lose.
“The coir logs are not preseeded; we do that ourselves,” he says. ‘We grow our native plants. We core holes in the logs and put a mix of growing materials with the plant, then grow them in a nursery setting. I started growing logs for Campbell’s Ditch in January 2007; the consultant had wanted me to be ready by March, because that’s when he thought the project would start. However, it didn’t start until June, and it lasted through September—but most of those months were filled with the dirt-moving part of the job. Our installation of SC250 blankets and logs took a crew of five people about four days total, and heavy equipment was not used to put in the logs and blankets.”
The water that flows through Campbell’s Ditch was dammed and diverted away from the waterway during construction to minimize sediment issues as well as to satisfy an agency required “grow-in” period for the seeds under the TRM.
Blanketing the Soil
Livingston County, MI, about 35 miles west of Detroit, started to boom in the 1970s. Where the former land-use was agricultural—meaning that the ground was pervious, with good drainage—the suburbanization of the county required the building of impervious roads, parking lots, and residential and commercial buildings. When the rains came, the remaining soil, as well as Michigan’s many natural water sources, had to be jealously guarded. Thirty years later, Livingston County still grows—and erosion control is more important than ever.
When Brighton, MI’s, Wagner Excavating Inc. was recently hired to develop a commercial project in the area, two tasks were most important: easing the site’s slopes to ensure that soil didn’t run off onto the surrounding roads, and securing a natural drainage pond on the site.
“Acme Enterprises Inc., which will build its new headquarters on the site, was the client,” Wagner president Dan Wagner recalls. “The rest of the site will be commercial, divided into approximately 10 to 12 individual parcels. There were a number of slopes on the site. Before mass grading, the topography varied 25 feet from the highest to the lowest points. Afterwards, the site contained 12- to 5-foot variations, or 3:1 to 4:1 slopes. Initial work on the project was winding up in late November 2007. The site was going to have to go through winter without vegetation. We did seed, but it wouldn’t establish before the snows came. The site would have to sit four to five months, enduring snows and heavy rains. Thus far, the slopes have held. The EC blankets we installed have worked quite well.”
The client mentioned the use of EC blankets in its specifications. “We bid the project in May or June of 2007. The client was concerned about erosion, period, no matter the season. Many times projects are bid out in spring, but then, by the time you install, it’s the end of the year. In many projects, the specifications call for EC blankets, but if it’s the time of the year when there’s little erosion, they might eliminate that part of the specification. However, at that time of year, late fall/early winter, the client wanted blankets everywhere. We installed Erosion King 8- by 112.5-foot blankets, which contain 100 square yards in a roll. We seeded before putting them down—there were no seeds in the blankets—and stapled them into place.”
Wagner bought his blankets from nearby Rhino Seed & Turf Supply. “We’ve been using Rhino products for quite a while—about 15 years. We’ve bought a lot of seed from them over the years. We do hydroseeding, too, and have used blankets a number of times, depending upon the location of job and its specifications. Our main forte is doing the mass grading for subdivisions, getting the roads in. A big part of our work is to restore topsoil, seed, and mulch in any areas we disturb.”
Currently in its 22nd year, Wagner Excavating began as a family business in a slightly different field. “My dad actually started a landscape construction business in 1955, which I joined after I got out of school. In 1986, a contractor friend needed some help—could I use my heavy equipment on his jobs if we were slow? It made sense to keep our equipment working, while helping both our businesses. The next year, I started doing grading and excavation myself, creating my own business. After my dad’s stroke, I took over his company as well.”
This past winter’s Acme project was a typical one for Wagner’s firm. “The site contained a natural retention pond—we didn’t have to dig one. We surrounded it with blankets and a silt fence to keep any high water from eating up more of the site. We also blew straw on the majority of the site. Only around the pond, and anywhere there was a slope leading to the curb, did we use straw blankets.”
And, as is often typical of Michigan, the weather caught up with them: “As it turns out, we couldn’t complete a 2-acre area. Everything froze around Thanksgiving, so we couldn’t work.” The project was finished in the spring.
Janis Keating is a frequent contributor to Forester Media Inc. publications.
EC - Products and Services Directory 2009 |
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