Watch the video on Stormwater: Reducing Erosion.
Most builders implement water management strategies to keep water moving down and away from the home's exterior shell, but due to recent rulings by the Environmental Protection Agency (EPA), all builders should be concerned with how water moves down and away from the entire jobsite as well.
In 1972, the U.S. Congress passed the Clean Water Act (CWA), which was a mandate to restore and maintain the health of America's lakes, rivers, and reservoirs. Up to that point, chemicals, sediments, and toxins were flowing unchecked into public waterways and choking aquatic plants, poisoning fish, and costing taxpayers millions of dollars annually to dredge canals and reservoirs.
Construction jobsites are major contributors to polluting waterways because they are especially prone to heavy erosion. Grading, excavation, and exposed soil combined with the normal trash, debris, and chemicals used during the homebuilding process result in a murky cocktail that can easily flow into storm drains after a rainstorm. To address this problem, the Environmental Protection Agency (EPA) established the National Pollutant Discharge Elimination System (NPDES) to regulate stormwater runoff from construction sites. The NPDES requires that builders obtain a permit before construction. Failure to have the proper permits can result in daily fines up to $27,500 per instance.
As part of the permitting process, builders must develop a Stormwater Pollution Prevention Plan or SWPPP (pronounced "swip"). A SWPPP explains how the builder will keep soil and toxins from leaving the jobsite and flowing into waterways. Within the SWPPP are a series of Best Management Practices (BMPs), which are the specific steps the builder will take to reduce jobsite erosion and run-off. It's important that builders understand the permitting process, but even more critical that they implement and maintain the BMPs on the job site. Failure to do so can result in lawsuits, fines, and work delays.
Here are a few examples of BMPs that can be part of a builder's SWPPP:
- Survey the lot to identify any slopes or uneven grades. By understanding where and how water will flow from the site, builders can begin to recognize trouble spots where erosion is most likely to occur. Most SWPPPs are required to have a lot survey of some kind.
- Install silt fencing at the bottom slopes or around the lot to help ensure that only water is making it into the storm drains. To install a silt fence, dig a trench about 6 inches deep where you're going to put the barrier. Insert the fence into the trench, making sure the material is flush with the bottom of the trench for the entire length. Backfill on both sides of the fence, and tie each fence in place with wire.
- Straw waddles, or straw rolls, are made of straw wrapped in thin mesh material. Simply place the waddles around flow areas and storm drains. The straw will act like a filter to trap the soil in the water.
- Put off clearing and grading an area for as long as possible before construction. The longer the soil is left exposed to the elements, the greater the chance it will start to wash away.
- For areas were trees and brush have already been cleared, spray hydraulic mulch evenly over the soil. This will act as glue to hold the soil in place.
- You can also create a swale to divert water away from the construction site.
- Plant the grass around the curb and sidewalk before construction begins. This can create a natural soil filter during run-off.
- Install a shaker near the entrance and exit of the job site. A shaker is a rippled sheet of metal that helps knock loose dirt and mud off vehicles as they drive over it.
The EPA offers a wealth of information on SWPPPs and alternative BMPs. You can learn more about this program and get a free resource poster by visiting the EPA's website or clicking here.
In July, 2003, the EPA reissued the Construction General Permit (CGP) to extend coverage to construction sites that disturb one or more acres, including smaller sites that are part of a larger plan of development. Because of this, many builders who previously were unaffected by the permitting program now must submit SWPPPs and employ BMPs on their site. But regardless of whether or not a builder is required by law to reduce erosion, everyone benefits when builders take steps to reduce soil erosion and keep our waterways clean.
| 
