The article I'm reprinting below is the best argument I've yet seen for "green" methods for handling stormwater.
Urge your representative to co-sponsor the Green Infrastructure for Clean Water Act
"Stormwater runoff is a growing threat to water quality across the United States, carrying untreated pollution into our rivers and lakes. As urban development increases, we have less forest and grassland available to filter our water and replenish our aquifers -- and more impervious surfaces like roads, roofs and parking lots sending polluted rainfall into our waterways. This polluted runoff costs Americans hundreds of millions of dollars each year in increased drinking water treatment costs, decreased tourism revenue and loss of aquatic habitat.
A proven method that can help address this challenge is "green infrastructure," which uses natural systems like trees, green roofs and rain gardens to put rain water back into the ground where it falls. Unlike traditional water management methods like sewers and tunnels that dump untreated, polluted stormwater far away where no one can use it, green infrastructure provides communities with a source of abundant, clean water.
Green infrastructure also makes sense economically because it decreases the costs of building expensive hard infrastructure, increases property values and creates thousands of green jobs. And unlike sewers and tunnels, green infrastructure offers wide-ranging environmental and social benefits beyond just reducing polluted runoff. It improves air quality, lessens the urban "heat island" effect and provides better urban aesthetics. Studies show that green infrastructure also improves people's health, reduces crime and saves energy used to heat and cool buildings.
A bill has been introduced in the House of Representatives that would make green infrastructure a priority by funding research into green infrastructure techniques as well as communities undertaking green infrastructure projects. The bill also would instruct the Environmental Protection Agency to create a new green infrastructure program.
What to do
Send a message urging your representative to co-sponsor the Green Infrastructure for Clean Water Act (H.R. 4202)."
Copied from an activist alert from the Natural Resources Defense Council.
See news here about Philadelphia's green infrastructure plan.