Deeproot Blog: Green Infrastructure for Your Community – blog and articles:

Green Streets have become a more common feature of the urban landscape in cities and towns across the United States and abroad. And for good reason: they provide substantial value in community aesthetics, redevelopment, livability and environmental compliance. You may know from personal experience or previous blog posts that water resources and ecological engineers use stormwater controls like bioretention, permeable pavements, infiltration trenches and street trees in collaboration with landscape architects and urban designers to design and build “Green Streets” that should decrease the volume of stormwater and pollutants that leave the right-of-way.

But how well are these Green Streets working for stormwater control and treatment?

It is an important question because for many Green Streets projects the impetus is downstream water quality protection, watershed restoration or combined sewer overflow (CSO) reduction. There are two components to evaluating Green Street stormwater performance: (1) hydrology, which includes runoff volume and its rate of discharge and (2) water quality treatment or removal of pollutants transported in runoff.

Surprisingly, there are very few peer-reviewed research papers that have evaluated Green Streets on a stormwater control and treatment basis. There are a couple of factors related to the lack of available datasets. One factor is the “newness” of the Green Streets and Green Infrastructure movement; there simply has not been sufficient time for researchers to find a project, develop a monitoring plan and protocol, obtain funds for the study, conduct the field study, evaluate the dataset, and finally report and publish the findings. The process is long. Another contributing factor is the difficulty in monitoring and instrumenting Green Street projects for research. These projects are located within the right-of-way among existing municipal stormwater and roadway infrastructure, which makes it very challenging to isolate the impact of a Green Street project.

Fortunately, some non-peer reviewed datasets are available and provide some insight on basic Green Street performance, but the study and evaluation is typically not as rigorous as those found in a peer-reviewed journal. Click here to see the sources and further links