By Stacy Hunt
The University of Wisconsin estimates that, without erosion control, about a dump truck and a half of soil washes into surface water for every acre of construction sites in the state. Even beyond the construction phase, erosion control on residential properties is important to reduce water intrusion from misdirected stormwater and decrease the environmental impact. The EPA's National Pollutant Discharge Elimination System (NPDES) and new regulatory requirements mean that builders have to consider not only erosion but stormwater management much more seriously than in the past.
Preventing erosion during and after construction is reasonably simple but time-consuming. The first focus should be on minimizing the removal of trees, grasses and plants and replanting quickly with fast-rooting vegetation where removal is necessary. Land cleared for construction can produce as much as 2,000 times more sediment than forest or meadow land.
An interesting approach to preventing erosion during construction was developed by Soil-Tek and showcased at the 2007 PATH Concept Home in Omaha, Neb. The system is basically a "sock" filled with mulch, which was moved around the perimeter of the site to provide perimeter runoff control for the site. The product is biodegradable, so it eventually breaks down into the site. It controls sediment runoff without becoming a source for more construction waste. In addition to this product, Soil-Tek offers a system that blows a blanket of compost injected with grass seed onto bare dirt areas. The process provides a quick, low-water approach to reseeding areas disturbed by construction. A number of other "vegetative blanket" systems are available on the market.
Here are some more practices to help reduce erosion during and after construction:
- Phase construction to allow "just in time" clearing of areas to reduce the opportunity for soil to erode before it's built on or finished.
- Create a rock or gravel drive to reduce tracking dirt from work vehicle tires leaving the jobsite.
- Retain dirt on the down slope of the jobsite temporarily until final grading is completed; avoid leaving piles of dirt on roads or near waterways. Cover any piles that will be kept during construction temporarily.
- Use dikes, berms and swales to direct water around areas of highly erosive soils, making sure that the channels are reinforced to handle a 10-year storm event.
- As soon as possible, attach gutters and downspouts to direct water away from the home. Use downspout extenders and additional piping to direct water away from the home until construction is complete and vegetation is established to handle runoff.
- Provide inlet protection for the storm sewer as a last line of defense to keep sediment from reaching storm sewers.
You may need special considerations for erosion control if your property is very steep, close to a waterway, has more than an acre of disturbed land, or gets significant runoff from neighboring properties.
Consult with a professional landscape designer, who can help you determine your soil type and design plantings, turf areas and drainage systems to most effectively reduce erosion to your property. To ensure proper erosion control after construction, a deliberate landscape design is critical. Your landscape designer can employ a variety of techniques and systems to reduce erosion on your property, including underground tubing or perforated piping to redirect rainwater, permeable paving materials, and/or French drains.
Efficient erosion control is critical to reducing the environmental impact of stormwater runoff, as well as simply to meet new regulatory requirements. The Environmental Protection Agency provides extensive guidance and resources on erosion control and stormwater management. Additional information and resources can be found at the Stormwater Manager's Resource Center.
Stacy Hunt is a freelance writer and consultant on building science and green building. She is the former business manager for BuildIQ.
| 
){kind=logo}
)
