Historically, roadways were designed primarily to carry cars and storm sewers were designed to move water away from the street surface rather than allowing percolation along the way. In older cities such as central Washington, D.C., combined sewer systems were designed to carry sanitary sewage and stormwater in one piping system. The result of this combined system is that during heavy rainfall the capacity may become overloaded and the excess is discharged into the waterways. Today, that system is not only aging, but also a major source of pollution. According to the Anacostia Riverkeeper, the system spills an estimated average 2 billion gallons of untreated sewage mixed with stormwater into the water way each year.
There is a pressing need to adopt new technologies and make critical improvements to our degraded urban infrastructure. We seek to rethink streets as both green corridors that ameliorate stormwater issues, and pleasant and engaging outdoor spaces for the public to enjoy.
Green infrastructure and green streets are a cost-effective and sustainable alternative to existing stormwater systems. These solutions not only improve water quality, but have the ability to improve air quality and reduce urban heat island effects, while improving habitats and the health and welfare of communities.
Bagby Street reconstruction, Houston, Texas. Image: Design Workshop