“The erosion control industry is getting ready to take a major step forward nationwide,” says Eileen Straughan, president of Columbia, MD’s Straughan Environmental Inc. “It’s growing in both installation expertise and site management, but most importantly in outcomes for water quality in receiving waterways. I say this really because of the new EPA numeric effluent limitation guidelines for construction sites. In Maryland, attention to construction-site discharges has been aggressive because of the Chesapeake Bay, and particularly now that EPA has promulgated a TMDL [total maximum daily load] for nutrients and sediment for the bay. Our Maryland Department of the Environment and the authority delegated to our counties to enforce the NPDES general permit for construction-site discharges have been pretty rigorous in managing sediment discharges from construction sites.”
However, Straughan doesn’t always see this attention to detail in other US regions. “When I travel to other states and see construction projects, and the comparative lack of sediment controls and site maintenance, I recognize and acknowledge the need for EPA to promulgate a nationwide ELG for construction-site discharges. Nationwide, I see a trend toward more rigor with erosion and sediment control device installation and maintenance, and far more rigor on the design side-to construction-site sequencing, to minimize the amount of land area exposed to erosion-combined with ensuring those areas exposed are controlled by appropriately sized and maintained erosion sediment control devices.
“Because of EPA’s pending ELG, other states must become more rigorous in implementing good design, BMP installation, and inspection, as well as BMP maintenance,” she notes. “States that are lagging in implementing EPA’s construction general permit really can’t lag anymore; they risk losing their NPDES permitting authority. Worse than that, owners and construction contractors risk some pretty hefty fines for violating the Clean Water Act-to the tune of $32,500 per day of violation. At those costs, you can buy, inspect, and correctly maintain a lot of BMPs.”
She points out that once the controls are in place, it doesn’t always mean the job is done. “I see construction-site inspection and management-including staying apprised of the local weather forecast-providing a key role in the success of construction-site erosion control measures. From ensuring that sediment control devices are maintained optimally to provide maximum capacity for the next storm, to minimizing disturbed areas, to ensuring placement of redundant controls such as mulch berms, super silt fence, coir fiber rolls, and more-the site manager really has control over site management, to reduce and minimize the potential for sediment to leave the construction site and enter nearby waterways.”
Water, Water Nevery-where
A key component to stopping erosion is establishing soil-retaining vegetation. However, getting that vegetation started requires water, and few sites contain such. If returning to the site to add water from time to time was the only option, few jobs would be cost-effective. Kym Kelley, president of Reno, NV’s Kelley Erosion Control, has found an easier solution. “For Caltrans [California Department of Transportation] jobs, we’re often responsible for both maintaining and planting the site,” Kelley says. “During one such job, back in 1998, we opted to use DriWater.”
DriWater Inc.’s time-release water is water bound in the form of a solid gel; the company describes the product as a “self-contained non-polymer drip irrigation system.” The gel is used for watering and providing nutrition solution for plants (zinc and acetic acid, which stimulate root growth). DriWater is available in 30- and 90-day versions.
“DriWater wasn’t in the specs,” Kelley notes. “We just used it because we knew about the product. We didn’t want to be there at the site, always watering. We had put in native plants no bigger than 1-gallon size-shrubs, sagebrush, bitter brush. Even though this project was done in the spring, we couldn’t depend upon getting rain; there was no nearby water source. Because we used DriWater, the plants lived, and that was the main objective. We maintained that site for a year and had to replace it a couple of times.”
Adding more gel was easier than the alternative. “Had we not used it, we would have had to take a water truck, done traffic control, and hired a crew to do the watering several times. To water in remote areas, you also have to drag out 1,000 feet of hose. Difficult. Costly. DriWater was a money saver.”
As opposed to some contractors who plant and move on, Kelley says his projects usually require maintenance. “We just finished a five-year contract for one project, a Caltrans job. Eighty percent vegetation survival was a requirement. Our choices to achieve that requirement: either replant when needed, or make sure what you have planted takes hold. Of course, the second choice is preferable!
“We pre-water the area, plant, put in DriWater, and water, and that actives the product,” she explains. “DriWater is not an absorbent; it’s water mixed with two food-grade ingredients. It’s the soil that activates the product to give out water. When the DriWater is done, in about 90 days, you have to add more. How long the product lasts depends upon the heat and dryness of the climate. Of course, in the desert, it can go faster-maybe 45 days. We knew the product worked, we had good success in our planting, and we know it saved money-a win/win situation.”
Kelley finds the product works on nearly everything. “We’ve used it on 5-gallon plants, 25-gallon evergreens-all of those on the site are still growing. It is used on established plants; it’s not for hydroseeding. In many jobs, we both hydroseed and install plants. Usually we plant first, then hydroseed around them.”
Most of Kelley’s projects are done in the fall. “We might have to put in new DriWater in, say, in April. A reason it lasted longer: There was some snow cover, and microbes in the soil are inactive then, so the DriWater won’t work. It will freeze at 25°F. Then, the ground is moist after snowfall. So the DriWater will be there in the spring when the ground warms up and microbes become active again.”
Recent projects included reclamation after two fires in Nevada’s Washoe County. “This work was funded by American Recovery Act stimulus money. The project entailed hundreds of acres. Of seven fire sites put out to bid, we won two of them. As the Recovery Act was designed for putting people to work, instead of aerial seeding-which would have made us more money-we used broadcast seeding, which put more people to work. We hired out-of-work building contractors and engineers and gave them an opportunity to make some money.
“We decided to use DriWater; no one required us to do so. However, when we work with designers and make recommendations, we tell them we think it will be of benefit to the project. No one has prevented us from using it; we’re responsible for making sure everything lives, so we make the decision. I truly believe in the product, and will continue using it.”
Sustainable Is Better
Ecologist Britt Faucette, CPESC, LEED AP, is director of research and technical services for Grafton, OH’s Filtrexx International, and he is also a co-author of the book, The Sustainable Site, recently published by Forester Press. This August in Anaheim, CA, he will give a presentation at StormCon, based on the book, titled “New Compost BMP Design Manual for Low-Impact Development and Green Infrastructure.”
“A couple things make my presentation unique-for one, sustainable BMPs,” he notes. “The industry has already been doing this to a certain extent, but practices and products often used in the stormwater field are not green or sustainable themselves, even if the application may be an environmental one. All applications in this book are sustainable; all use compost in their makeup.”
But just not any compost will do. “Compost is always 100% recycled, but it’s also locally available, bio-based, and indigenous. Using local compost reduces our carbon footprint, because it’s not being shipped everywhere, while it also keeps organics out of landfills. There’s a chain of compost across the nation-about 4,500 US composting facilities, located in every state and region.”
Faucette’s book specifies what criteria compost has to meet to be used in this application. “Where the compost begins really doesn’t matter; it’s mostly greenwaste or yardwaste materials. I concentrate on end-product quality. The composting process breaks down most harmful pollutants and stabilizes nutrients, carbon, and organic matter. It’s a natural pasteurization process. Plus, most facilities will do testing for contaminants. The compost used in my examples must be biologically stable and mature, so it doesn’t inhibit plant growth.”
Using compost as a BMP creates a more natural result, he explains. “Bio-mimicry isn’t rocket science,” Faucette says. “Using natural materials and processes, you’re benefitting from the services of nature. Nature filters stormwater through vegetation, healthy soils, organic matter, and beneficial soil organisms. Erosion control and stormwater runoff reduction come from stable soil ecosystems, organic matter, vegetation-it all works together There are two main specifications for compost: as a growing medium and as a filtration medium.
“In the book, I outline 24 different applications for compost. There are four broad categories: compost socks that grow vegetation, compost socks to filter stormwater, compost applied as a blanket on soil, and compost engineered with soil and other natural materials.”
Why did he see the need to write a book? “For a couple of reasons. A lot of folks asked for something like this. We’re seeing a fair amount of technical books on LID and green infrastructure, and a ton of growing interest in green applications, like compost, in these subjects. I’ve put it all together in a technical manual for the community.”
How will this book fit in with the EPA’s new effluent limitation guidelines? “Ten sections in the book are for construction sites,” he says. “Using these will help you reduce sediment. Some are specially designed to reduce NTUs [nephelometric turbidity units] as well.”
Faucette thinks his instructions will come in handy for those trying to obtain LEED, or Leadership in Energy and Environmental Design, certification for their projects. “Being a green building rating system, LEED contains various sections-not only on designing and building green buildings, but also on the sites around the buildings. The more points you get for green building, the higher a certificate rating you get. LEED prefers more natural or recycled materials, items that will blend with the native landscape, that fit with the climate, that reduce energy and water use-and items that are locally available. Compost fits right in.”
Finding a Way to Please EPA
Jerald Fifield, Ph.D., CPESC, CISEC, of Parker, CO’s HydroDynamics Incorporated, is a founder of the Certified Inspector of Erosion and Sediment Control (CISEC) certification program. At StormCon in August, he will present a paper titled “Designing an Effective Sediment Containment System,” which will take into account the EPA’s new effluent guidelines.
“This is all about sediment ponds,” he explains. “Historically, much of the “˜science’ basis for designing sediment ponds centered around sanitary engineering-how they capture solids from sanitary ponds. But what is presented in my paper is totally different. Sedimentation is the whole thrust of my paper: How can we make sediment fall out of water somewhere where we want it to, not in lakes and streams? When you have suspended particles in water, you’ve lost the whole battle in saving streams-until you have the particles removed.”
Fifield’s paper mentions “new equations,” mathematical formulae for determining what procedures would best solve a site’s sediment problems. “I’ve developed a series of equations, so designers can design an effective sediment pond. This is more complex than what we’ve done in the past, which allows designers to be more accountable.”
That shift in accountability should ease the mind of many a contractor. “In the past, when a site had runoff, contractors got blamed for everything. Not fair. Construction crews put in what was specified on paper; designers created that paper, which had been approved by regulatory agencies. Often, construction crews are putting BMPs in, even if those don’t seem to make sense for the site. Of course, regulators often set up what BMPs are to be used, so one can’t lay all the blame on designers.”
In a perfect situation, every step of a site’s plans would be thoroughly checked and rechecked. “Plans are supposed to have been reviewed by regulatory agencies, but many times the plans are being reviewed by people without the proper education. These folks also need more training; “˜one-size-fits-all’ regulations don’t work.”
Soils and climate are just two variables that make sites unique. “For example, here in Colorado, it sometimes takes us two to three growing seasons to get grasses growing,” Fifield notes. “Designers have to know how to implement equations, plus understand what rains and soils there are, how long it takes to establish vegetation, and what are the winter conditions. The industry is increasingly concentrating on establishing native vegetation. Sometimes, it takes so long to get vegetation going here-in the meantime, you get more erosion. Rain is needed to get vegetation started, but you can’t control it. When we do get precipitation (we get only about 14 inches per year), it comes hard. Then, there are times we find a plant species that can work with these conditions, but we are told not to use it, because it’s not native.”
Fifield’s paper suggests adding polymers to runoff waters, the main ones being polyacrylamide (PAM) and chitosan. Although they both can cause flocculation, adding polymers is not an “either/or” proposition, he says. “What you’ll choose has to do with the electronics valance with the type of soils. It is my understanding that lower pH soils have more positive (cationic) charge; higher pH soils have more negative (anionic) charge. In addition, the environment around your site matters; if fish-filled streams are nearby, you have to be careful with positively charge polymers that might cause fishes’ gills to attract sediments, which would smother them. On the other hand, if the site allows the use of anionic polymers, its negative charge can repel particles from fishes’ gills. Either way, care must be taken; whatever you add to the soil, it must not pollute waters with something new.”
Proper polymer dosing is also crucial. “Some contractors might think “˜more is better,’ and that’s not the case,” he says. “Plus, even though the polymers would be added to solve a problem, not everybody is 100% sure those additives won’t cause other problems years from now. Hypothetically, floccuents will sink to the bottom of the pond, and eventually be scooped out along with the sediment. Do the polymers ever break down over time and cause problems down the road? Some say no; some polymer studies indicate that flocculents containing anionic polymers sink to the bottom and do no harm.
Another consideration, he says: “What kind of pond is on the site? If it’s a detention pond, holding water for a certain amount of time before releasing it, rather than a retention pond, which holds onto water and allows it to filtrate into the soil, that might change your mind about what polymers to use. It’s all site specific.”
Again, Fifield stresses that knowing the soil will guide the project. “Good designers will go to the NRCS [Natural Resources Conservation Service] and check the soils. Sometimes folks will identify the soils because they’re told to by regulators-but then they don’t do anything with this information, or at least they’re not using it the way they should. On the other hand, sometimes designers and contractors who do more than “˜what’s required’ get their hands slapped, because they’re not doing the project just “˜by the book.’
“Polymers are not a panacea; they’re just one tool that works,” he adds. “When using polymers, one may have to know the soil pH, because they may not work with high-pH alkaline soils. Should designers recommend adding some acid to bring down the pH? Maybe; but is it a good idea to add acid to water that didn’t have it? No single thing works for any and every case. I always recommend sending soil samples to the manufacturer of the polymer you’re using and asking them which formulation to use.”
Rules are fine, but what happens if the rules change, or new technology allows for better, more cost-effective results? “Regulators need flexibility; they might allow the industry to try new techniques that work, but everyone along the chain of command needs to be accountable. If the new doesn’t work, go in there and fix it.”
The proposed EPA regulations on turbidity limits (280 NTUs) have some EC professionals rattled. “Some are afraid that the new regulations will open up a can of worms. Originally, EPA suggested 13 NTUs, which was based primarily upon the use of active or advanced treatment systems (ATSs), consisting of polymer-assisted clarification, followed by filtration,” Fifield explains. “Thirteen NTUs? That’s about the same rating as bottled drinking water! Where did that number come from? Is it too restrictive? Whatever limit they settle on, it must be supported by scientific studies. Maybe 280 NTUs will become the norm, despite an upcoming court case, but I wouldn’t be surprised if the EPA will go lower than that.”
Difficult as regulations might be, Fifield notes that they’ve done the country good. “Some Americans don’t know, or have forgotten, what the environment was like 40 years ago-polluted air and water-but we have made strides.”
