In "Green Infrastructure Could Save Cities Billions," the Atlantic quotes a report co-authored by ECONorthwest, American Rivers, the American Society of Landscape Architects, and the Water Environment Federation, which examines the cost-effectiveness of green infrastructure projects around the United States. It reads:
Looking at 479 case studies of green infrastructure projects around the U.S., the report finds that the majority of projects turned out to be just as affordable or even more so than traditional "grey" infrastructure. About a quarter of projects raised costs, 31 percent, kept costs the same and more than 44 percent actually brought costs down.
"The lesson learned so far by early adopter communities who have already implemented green infrastructure in a significant fashion is that a wide-ranging commitment to including green infrastructure stormwater approaches, on public as well as private properties, can result in long-term fiscal savings for local governments as well as provide numerous, tangible economic and community benefits through related ecosystem services," notes the study, co-authored by the American Society of Landscape Architects, American Rivers, the Water Environment Federation, and ECONorthwest.
The costs of traditional infrastructure are especially pronounced in cities and regions with combined sewer systems that collect both sewage and stormwater. During heavy rainfall, these systems are often overwhelmed, pouring sewage-laden water into drinking water sources and greatly increasing water treatment costs.
The rest of the article is available from the Atlantic, here.
You can download the report, and others in the series, Going Green to Save Green: Economic Benefits of Green Infrastructure Projects, here.