Green Streets and Sidewalks: Design and Lessons Learned

The City of Alexandria, Virginia is a highly urbanized City with approximately 160,000 people living in 15.3 square miles, and approximately 48% of the land area is considered impervious. The City currently maintains over 300 miles of roadways and 430 miles of sidewalks, most of which have no water quality treatment or quantity controls. The City of Alexandria proactively regulates development and redevelopment projects under the Chesapeake Bay Program and Virginia Stormwater Management program to reduce pollution from stormwater runoff.  However, often these projects limit their stormwater treatment to the private project footprint leaving the public rights of way untreated.

Roadways and sidewalks are well known contributors of stormwater runoff and pollution.  In 2014, the City created its first Green Sidewalks BMP design guidelines aimed at reducing stormwater runoff and pollutants from development and redevelopment.  However, almost immediately after approval, the guidelines were out of compliance due to changes in state regulations.  In 2018, the City partnered with AECOM to update the guidelines, make them more flexible and be consistent with current stormwater regulations.  The new guidelines were implemented in 2020 as the City of Alexandria’s Green Street and Sidewalk Stormwater Design Guidelines. These updated guidelines present a variety of stormwater management Best Management Practices (BMPs) that can be selected and configured within the public street and sidewalk right-of-way to meet the goals and context of a development site while treating stormwater runoff.

This presentation provides an overview of the development of the guidelines and the decision-making process behind the creation of new and updated designs, the policy implementation for construction of BMPs and the challenges it has presented, and the anticipated successes and challenges for the implementation in the future.