Anything more than "moderate rain" forces sewage treatment plants to overflow, Gennaro said, with the excess water and its pollutants running into local waterways.
"How can we expect to have our sewage clean if we have 27 billion gallons of combined sewage overflow?" Gennaro said. "We will never get to where we need to be in terms of storm water management unless and until we integrate natural solutions to this vexing problem."
Barbara Brown of the Eastern Queens Alliance, a cluster of civic associations, said the plan "will help to seriously curtail the flooding and sewage that ends up in their basements," referring to residents in southeast Queens, where flooding is widespread during storms.
Gennaro said the city "can control storm water at its source" by "something as simple as planting trees," using more sensible tree pit design and installing green roofs that collect storm water. Storm water can also be naturally absorbed through vegetation, green areas and impervious surfaces, the councilman said.
He said there are added benefits from using green technology to manage storm water before it enters sewage treatment plants, noting that green methods better protect buildings from heat and lower air conditioning bills.
"This is a great opportunity for the city to embrace this kind of change," Gennaro said. "This is economic development. This is entrepreneurship. This is greening the city."
The bill "goes further than what was put forward in PlaNYC," he said, referring to Mayor Michael Bloomberg's sustainability plan by 2030 that included greening the city. "This legally commits the city to doing a comprehensive study... and the developing of a comprehensive, sustainable storm water management plan."
A draft of the plan would be due Oct. 1, 2008, Gennaro said, with a Dec. 1 deadline for the final version.
Reach reporter Howard Koplowitz by e-mail at hkoplowitz@timesledger.com or by phone at 718-229-0300, Ext. 173.