Adding protective barriers around street trees could reduce load on city sewers, study finds.

In an effort to curb sewage overflows, New York City has turned to green infrastructure: right-of-way bioswales, green roofs and rain gardens, among other practices. These measures help decrease stormwater runoff by increasing pervious areas and introducing water-loving plants that can absorb some of the water and encourage evaporation.

Over the next 18 years, New York City’s 2010 Green Infrastructure Plan will spend $2.4 billion on green infrastructure— green roofs, tree plantings, and increased vegetation— to combat coastal pollution. But how does green infrastructure work and how effective is it really?