By Sabri Ben-Achour
When rain gives the city a rinse, all the dirty wash water ends up in rivers and creeks. Metals, bacteria, - even air pollution - get into the water that way. That is what's known as stormwater pollution, and it's what the EPA is proposing to control through a what's known as an "MS4 permit."
Usually states write these permits for individual counties or municipalities, but for D.C., it's the EPA that writes the permit. In doing so it is creating a template for municipalities across the country, says Cori Lombard, a legal fellow with the Natural Resources Defense Council."As a national model this is as big as it gets," she says.
The permit would require the first 1.2 inches of rainfall to be retained or absorbed in one way or another, using pervious surfaces, green roofs, or retention pools for example.
Only federal and municipal property owners would be affected by the permit, and it does not apply to existing properties unless they are substantially redeveloped.
All new construction, however, must contribute no more to stormwater runoff than would a meadow. The permit would also have D.C. plant more than 4,000 trees each year, and expand green roofs by 350,000 square feet over five years.
Amy Edwards, with the D.C. Building Industry Association, warns the permit might contribute to sprawl.
"The costs could just become unmanageable so that folks start looking for pristine areas in which to do new development," says Edwards.
She argues that the permit places stormwater reduction over other sustainable goals, like energy efficiency.
Cori Lombard, with the Natural Resources Defense Council, says there is no evidence to back up the claim that development would be shifted to outlying areas. She says it's cheaper to mitigate stormwater runoff at the front end.
"What the building industry maybe isn't taking into account is the back end cost of stormwater pollution, when the government and the taxpayers have to pay to clean these waters," says Lombard.
Both groups, and many others, will get to have their say; the public comment period ends Friday. The EPA hopes to have a final permit by August.