The Environmental Protection Agency's Integrated Municipal Stormwater and Wastewater Planning Approach Framework released in June provides guidance on development of an "integrated" planto help local governments meet their Clean Water Act obligations. It allows local governments to implement rules that encourage or require green stormwater infrastructure such as rain gardens, green roofs, cisterns to collect rainwater for later use, permeable pavement, and bioswales.
The purpose of the new approach to stormwater is to use natural elements to reduce the amount of rainfall that makes its way into city sewer systems. Stormwater can overwhelm storm drainage systems in heavy rains and cause sanitary sewers to overflow into rivers, harbors, and lakes.
"We're at a tipping point," says Katherine Baer of environmental group American Rivers, which is working with communities to implement green infrastructure. "We're going to see a lot more of these practices that protect, restore or replicate natural functions, as cities grapple not only with water quality, but with livability and climate adaptation."
More than a thousand US communities have sewage overflow problems, says one expert. Because of the high cost of replacing this infrastructure, new tools are necessary. Building codes may well adopt these new techniques as a result.
(http://www.theguardian.com/environment/2012/aug/23/how-cities-nature-cut-pollution
