Erosion control

|  June 12, 2007 |

The rules regarding erosion control at construction sites are changing – and the stakes are getting higher. To complicate matters further, there isn’t just one set of regulations. The federal government sets overall requirements, but then state, county and municipal agencies can tack on more guidelines.

The Environmental Protection Agency’s Phase II Storm Water regulations took effect in March, putting jobsites that disturb one acre or more under the agency’s watchful eye. The statute allows maximum penalties of $27,500 per day, per violation. (See the sidebar at the end of this article for more information about Phase II.)

And as sediment continues to clog the nation’s waterways, causing flooding and costing taxpayers millions of dollars to clean up, federal and local enforcement officials are giving contractors fewer warnings. “Erosion control is getting to be more of an issue because it affects everybody,” says Les Van Ornum, president of Van-Boh Systems, which makes a silt fence installer. “Five years ago you might see a municipality come up to a contractor and say, ‘Hey, make sure you put that silt fence into the ground.’ Now they just fine you.”

The good news is that manufacturers of erosion control products, contractor associations and EPA itself are posting a barrage of information on the Internet to help you understand the rules, select the right erosion control products for your jobsites and install them correctly. (See the Internet resources sidebar at the end of the article.)

Mulch, blanket, mat or silt fence?
Selecting the wrong erosion control device can be a costly mistake. Not only will you have to redo your work, you may be fined as well. Still, Marc S. Theisen, director of business development for SI Geosolutions, a maker of rolled erosion control products, says contractors don’t always know when, where or what devices to install. “We often see the wrong products in the wrong places,” he says. “It’s a huge problem.”

Several software programs are available to help you choose the right product for your application, says Todd Croke, assistant manager of technical services for North American Green, a rolled erosion control product manufacturer. The software allows you to plug in information about the slopes or drainage channels, soil types and climates at your jobsites, and it then makes recommendations about the type of products you should use. North American Green offers a free CD of this software or you can download it from the company’s website, SI Geosolutions offers design software as well at

If you are still unsure about what product to use, Kendall Bunch, national sales manager for Erosion Control Systems, recommends calling one or more manufacturers to get their opinions, especially if the application is severe.

Install it right or do it again
Even if you have the right erosion control product, if you don’t install it properly it might fail.

The Erosion Control Technology Council, an organization of manufacturers working to develop performance standards, testing procedures and guidance on application and installation of rolled erosion products, offers on its website a 12-page document on how to install blankets and mats on slopes and in channels. The guidelines are easy to read and include several diagrams and photographs. To view the document, log on to and click on “Resource Center.”

In addition, all manufacturers have recommended installation procedures, and those usually come with the product or can be found on the manufacturers’ websites.

Theisen says one common mistake contractors make is not installing enough staples or pins throughout the blanket or mat. “It’s not very much fun installing these things,” he says. “People tend to cut corners and that comes back to haunt them later. So sufficient pinning is important.”

Without the proper number of staples, wind and water may work their way under the blanket or mat before vegetation has a chance to get established. If that happens, you may have to pull back the mat or blanket and start over. “Without enough staples, it [the mat or blanket] balloons a little bit,” Bunch explains. “And when you get water underneath it, then you’ve got all kind of problems. Because the dirt is not being held in place and the seed gets washed away.”

You also must use the correct staple pattern. Most software programs that help you determine which product to use will also recommend a particular staple pattern. The installation guidelines on the ECTC website cover staple patterns as well.

Staples vary in length from 4 to 18 inches. Choose staples based on the soil type at your site. A short staple will work fine in clay because it will be hard to pull out. But in loose, silty or sandy soils, you’ll need longer staples. “If, for instance, you have a really sandy site and you put in 6-inch staples, it’s going to be a lot easier for that blanket to be pulled up even by wind,” Croke says. (See the chart on page 73 to learn which staples work best in various soil types.)

The edges of adjacent blankets or mats may or may not overlap, depending on manufacturers’ recommendations. If an overlap is necessary, usually 4 to 6 inches is sufficient. Croke says he often sees contractors overlapping the product too much – sometimes 2 feet or more. “You’re not only losing a lot of material there that you could be covering the rest of the site with, but it also causes a lot of cover for that particular area,” he says. “So you have a 2- or 3-foot section that vegetation may not grow up through because there’s too much cover on top of the soil.”

After rolled erosion control products are installed, someone should inspect the work to make sure it was done correctly. Theisen recommends walking the site and making sure pins or staples are driven in correctly, flush with the ground. The staples should be driven with a hammer or mallet, not stepped on by the installer.

Check local rules for silt fence installation
The biggest mistake contractors make when installing silt fences is not digging them into the ground properly, Van Ornum says. “If you have this material just lying across the ground with stakes, when it does rain, that sediment is going to go right underneath it,” he says. And if federal or local environmental authorities notice, you’ll be fined.

You should also check with local governments to find out whether there are any special requirements regarding silt fence installation. State rules concerning the depth to which silt fences must be dug into the ground vary from 6 inches to 12 inches. Van Ornum cautions that installing fences 6 inches deep isn’t always enough. “If you get a good rain one day, it would probably undermine the silt fence,” he says. “If I was putting it in and was really concerned about the environment, I wouldn’t put it in any less than a foot.”

Make sure the depth to which you install the silt fence is constant. For example, the trench shouldn’t be 8 inches in one place and 12 inches in another. If the depth is uneven, the fence will sag and wind and water could create pressure points leading to a washout. “When you have a fence that rises and falls, the top is not taut and that contributes to it collapsing,” says Will Callahan, president of Implemax, which makes a silt fence installer.

Create a U shape when installing a silt fence. “The ends have to be higher than the middle,” says Tom Carpenter, president of Carpenter Erosion Control, which makes a silt fence installer. “It seems like everywhere you go, people install silt fences in a straight line.” A curved shape will channel water to the center and keep sediment from running out of the area where it needs to be retained.

Carpenter also advises installing a new fence above or below a silt fence that has filled with sediment, leaving the old fence in place. Repeat this process as sediment fills new fences.

After the silt fence is dug into place, you need to mechanically compact the loose soil around it – otherwise, the next rain might wash it out.

Don’t just walk away
Most erosion control products require maintenance – at least at first.

EPA recommends inspecting rolled erosion control products after every 1/2 inch of rain or weekly if you don’t have a significant rainfall. “You can’t just install it and walk away and think it’s fine,” Theisen says. You should make sure the blankets or mats are still in place and the seeds did not wash away.

“Generally if you get a little sun and get a little rain, the seed germinates and does the rest of the work,” Bunch says.

Of course, seed germination varies with climate. In some Western areas, a year may pass before vegetation is an inch high, while in the Southeast you could have that in three weeks.

Regardless of the time it takes, once vegetation is established, the blankets or mats aren’t going anywhere. “If it’s been properly installed and the correct product was chosen, they’ll be no maintenance needed for the RECP itself after that,” Croke says.

You should inspect your silt fences, on the other hand, after every rain. Make sure the tie straps, wire or whatever you’re using to attach the fence to the stakes are stable and in good condition. Also make sure the fence is standing up the way it should and is still dug into the ground properly.

If you have a large site and water is being funneled to one spot, 1/4 inch of rain might be considerable, Van Ornum says. “That could potentially be a lot of water and a lot of pressure against that material,” he says.

EPA Phase II Storm Water rules
While Phase I of the Environmental Protection Agency’s Storm Water rules, effective since 1990, sought to stem sediment runoff from construction activity that disturbed five or more acres of land, Phase II – which took effect in March – extends many of the same regulations to jobsites of one acre or more.

Sediment accounts for more than two-thirds of all pollutants entering U.S. waterways. EPA asserts that control of construction site runoff is necessary because construction activity can, over a short period of time, contribute more sediment to streams than can be deposited naturally during several decades. As a result, excess sediment can quickly fill rivers and lakes, requiring expensive dredging and destroying aquatic habitats.

“Taxpayers are spending millions of dollars all over the United States to keep our waters clean,” says Les Van Ornum of Van-Boh Systems. “Because of that, everybody I talk to in federal and local governments is really enforcing storm water rules.”

And with maximum penalties of $27,500 per day, per violation, Phase II regulations are not something you want to ignore.

Phase II can actually apply to construction sites smaller than one acre if that work is part of a larger common plan of development or sale with a planned disturbance of an acre or more.

The Phase II rules require you to:
1. Submit a notice of intent including general information and a certification that the activity will not impact endangered or threatened species.

2. Develop and implement a storm water pollution prevention plan with appropriate best management practices to minimize discharge of pollutants from the site.

3. Submit a notice of termination when final stabilization of the site has been achieved as defined in the permit or when another operator has assumed control of the site.

EPA’s Construction Industry Compliance website, launched in May, includes a storm water section that contains EPA documents and plain-language information about Phase II requirements. The site was still under construction as of deadline for this issue, but features slated for the storm water section include an overview of the permit process and a categorized set of best management practices links.

A construction storm water pollution prevention plan checklist is currently available, along with links to state rules, fact sheets detailing Phase II requirements as they apply to construction sites and Phase II minimum control measures for construction site runoff.

To view this information, go to and click on the storm water tab.

Internet resources
Choosing the right erosion control product for a particular jobsite and installing it correctly can get complicated. And navigating the federal, state and local regulatory channels can be mind-boggling.

To help you out, manufacturers of erosion control products, contractor associations and the Environmental Protection Agency have posted information on the Internet explaining storm water guidelines, product selection and installation techniques.
Here are a few good sites to look up: – EPA’s Construction Industry Compliance website includes plain-language overviews of both Phase I and Phase II Storm Water regulations. It also contains information on the permitting process and links to state storm water rules., – At these sites you can download software that makes recommendations about the type of products you should use for individual jobs. You just plug in information about the slopes or drainage channels, soil types and climates at your sites. – Here you’ll find a wealth of information about selection and installation of rolled erosion control products. Tables show you the most appropriate product based on the slopes or shear stresses at your jobsite and a step-by-step manual will guide you through the installation process. – On the environmental page of its website, the Associated General Contractors of America publishes bulletins and newsletter articles to notify contractors about key environmental actions, deadlines, requirements, directives and policies that may impact them. You can also order a book listing basic cost-effective steps for installing, maintaining and inspecting erosion and sediment controls to achieve regulatory compliance.