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The Environmental Protection Agency, along with some northeastern states and municipalities, are enacting new, tougher rules to reduce stormwater runoff, a leading cause of water pollution. Whenever it rains on pavements, stormwater washes all kinds of pollutants into lakes rivers and estuaries. As part of a collaboration with Northeast stations, New Hampshire Public Radio’s Amy Quinton reports that builders are starting to adopt new technologies designed to keep contaminates out of the water.
On a windy day in Greenland, N.H., construction crews are putting the finishing touches on a 375,000 sqare-foot big box development. But before it was built, the Conservation Law Foundation was preparing to fight the project.
Attorney Tom Irwin says if it rains, he was concerned about what would wash into a nearby brook which runs into New Hampshire’s Seacoast.
“The brook was listed as being impaired for various metals including zinc and all of these pollutants could be expected to be present in the stormwater runoff that would come off the site in a conventional stormwater treatment system."
With more than 20 acres of hard surface, rain would also send runoff including car fluids, such as gasoline and oil, into the brook.
Again, Tom Irwin: "They were going to store it in pipes beneath the parking lot so that it could be metered out gradually into the brook -- very little in the way of treatment."
Rather than fighting a potential lawsuit, the builder worked with researchers from the University of New Hampshire Stormwater Center to try something different. Stormwater Center Director Rob Roseen says a key change was installing porous asphalt which acts like a sieve.
"Porous pavements in general are pavements that have holes in them and they allow rainfall to go straight through them."
Sands underneath the pavement help remove pollutants. On this site, Roseen says the stormwater is then funneled into what’s called a gravel wetland which is made of crushed stone.
"It’s an anaerobic system -- so you have microbes and roots that are acting on the stormwater as it travels through the stone.”
The idea is to help restore the land’s hydrology to the way it would have been, had there never been development that brought pavements and roofs. Many designers and developers in the Northeast have resisted using these techniques, in part because until recently, they were largely untested in colder climates.
But Roseen’s research shows there are additional benefits -- on permeable pavements, water soaks through and there’s less black ice.
"In the winter time you can get away with anywhere between 75 and 100 percent less salt than standard application rates."
Less salt means fewer contaminates washing into soils and streams. But Roseen says convincing builders of the benefits is still an uphill battle.
At a recent EPA conference on low impact development in Concord, N.H., Glynn Roundtree with the National Association of Home Builders says he’s still wary of the new technology.
"In it’s early times yet, there may be some risk of failure of these devices and somebody has got to take liability for that”
Roundtree adds that low impact development techniques can be more expensive especially when rehabbing an existing site.
But developers may not have a choice – some Northeast states and municipalities are enacting tougher rules for stormwater management.
In Massachusetts, any building with more than five acres of hard surface will be subject to new requirements.
New York City and New Hampshire are in the process of rewriting their rules, and the EPA has also come up with stricter standards for existing buildings near impaired bodies of water.
Steve Silva of the EPA:
“The low impact development techniques have the greatest potential for solving the problem, getting the watersheds back to the natural hydrology that occurred pre-development, and so it's probably most likely that those will be the techniques that people will use."
Back at the big box site in Greenland, N.H., owners are still nervous about the new designs and how long they will last. Because of that, only a portion of the parking lot is porous. But without this technology the Clean Water Act could have stopped stores from being built here at all.