March-April 2006

Keeping Sediment Onsite

Effective ESC during construction.

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By Dan Rafter

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The department has now approved the product for perimeter control around rainwater gardens in high-density parking lots, to be used as filter rings on inlet structures prior to gutter placement, and for a host of other uses.

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Seeking Innovation?
Thomas Horan, managing partner with Newbury Park, CA–based Eco-Blok, is always thinking of new products designed to make sediment control an easier task. That's why his company in mid-2005 introduced its new Eco-Bag.

PHOTO: WOOLPERT
Protecting an onsite inlet

Eo-Bag is a reusable durable container that can be filled with sand, gravel, or water to prevent sediment runoff and erosion on work sites. The bag's best feature is that it is reusable, so contractors will not have to constantly replace sand or gravel bags. Such cost savings are key to encouraging builders and developers to choose newer, more effective sediment control measures.

The current Eco-Bag costs $19. That version is a molded variety. Eco-Blok officials are now developing a second, lower-cost alternative that they expect to sell for $3 to $4 each.

"I have spoken to a dozen public works directors who say this is exactly what they need," Horan says. "The sandbags break and that makes a worse problem. These don't break. They can use them over and over again."

Horan isn't the only manufacturer hoping that the NPDES regulations encourage contractors to seek out more innovative products. John McPherson, vice president of research and development with Redmond, WA–based Natural Site Solutions, is banking on this, too.

His company distributes Storm-Klear Gel-Floc and Storm-Klear Liqui-Floc, simple controlled-dosing flocculants that reduce turbidity, phosphorous, metals, and grease in stormwater before it has a chance to leave a construction site. He hopes that contractors realize that by focusing on keeping water runoff clear, they are meeting the larger goal of sediment control: preventing polluted water from infecting other sites.

"If you had a construction site and you had no dust management or sediment control practices in place at all and yet were able to discharge clean water, you'd consider that a success, right?" McPherson asks. "You don't have to check dams, you won't have to erect much silt fence, but you'll still have beautiful clean water discharging from your site. If you can purify the water, it de-emphasizes the strict requirement for expensive best management practices."

McPherson, of course, recognizes that this sounds like heresy to many in the erosion control field. "We are kind of trying to change the face of this industry," he says. "If you can discharge clean water, and the contractor's feet are not being held to the fire to put straw on everything, to put blankets on every slope—all of these things that cost money—think how happy everyone would be. If they can do that and avoid endangering the environment, then it is looking like the problem is solved. Of course, those are fighting words in this industry."

McPherson recalls one particular project in which Storm-Klear saved the developer time and money. In 2001, a homebuilder was constructing single-family homes on a 10-acre site in Sammamish, WA. Problem was, dirty stormwater from the site traveled downstream and muddied up neighboring trout ponds. Amid an uproar from neighbors and watchdog groups, state officials fined the builder and shut down the site.

That's when McPherson, who is a chemist, stepped in and installed his company's Gel-Floc system on the site. "There was a lot of screaming going on at the time, I remember," McPherson says. "Lawsuits were being filed. It was pretty ugly. But within two to three weeks, we had the site back up and going. The neighbors' trout ponds were cleared. Everyone was happy."

To clear the stormwater discharged from the site, McPherson first sent it over a Gel-Floc unit and then directed it to a permanent stormwater retention base for gravity settling. After settling and further biofiltration, the Gel-Floc unit greatly reduced contaminant levels, including turbidity, metals, and phosphorus, in the runoff. After McPherson installed the Gel-Floc unit, state officials had no cause to levy any additional fines during the project, meaning that construction crews avoided further costly work stoppages.

"That's a good example of how a stormwater problem can be solved," he notes. "It's a simple system. Everyone likes the space shuttle, but for small sites, you really do need systems that are not complicated. Ours are not. We hope to be able to raise awareness of this approach to managing runoff."

Do such success stories mean a significant change in the way contractors approach sediment control on their sites? Paul McGrath, owner of L.V.H. Silt Fence and Erosion Control in Lemont, IL, thinks they might.

McGrath is already experimenting with more innovative and efficient measures of controlling sediment. He's become, for instance, an ardent user of McCormick Equipment's Silt Fence Plow. In October, he used the plow to install 11,600 feet worth of silt fence in a cornfield in New Lenox, IL. It took him and his crew a total of 55 minutes, using the plow, to do the job. He then had the job site staked, stapled, and completed in just five total hours. To do the same work on the 165-acre site of a future 350-home subdivision with a trencher would have taken McGrath, with double crews, at least two full days.

It's such savings in time and money, McGrath says, coupled with the ability to avoid large fines, that will ultimately make products such as the Silt Fence Plow ones that contractors seek out.

"I think people are getting more aware of how important it is to control sediment runoff from their sites," he says. "I still find myself explaining the reasoning to people, though. You still get the builders who put in silt fence and it's flapping in the wind. It's not trenched in at all. You can see water or dirt running under it. But once you educate people, they understand."


Author's Bio: Dan Rafter is a technical writer based in Illinois.

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