Green Area Ratio (GAR): An Urban Site Sustainability Metric

Washington, D.C.

Fresher air, cleaner water, cooler temperatures, and less runoff—there are compelling reasons to promote green space in metropolitan areas. Yet, in many cities, open spaces are often too small or fragmented to protect natural resources essential to public and ecological health. While regulations that mandate open space often exist, the results are not necessarily green or sustainable.

To help urban areas encourage and maintain green space in a way that sustains natural resources, researchers from George Washington University are using a grant from CICEET to recalibrate a decision support system from Germany for use in the United States. Communities will be able to use the Green Area Ratio (GAR) to set greening targets for new development or redevelopment, and then choose from a menu of techniques to reach these goals. In densely populated Berlin, GAR has been used successfully for more than 10 years.

Investigators are building on a previous evaluation, funded by the EPA, which looked at how the GAR could be applied to planning efforts in Philadelphia. The CICEET project will demonstrate this modified metric on roughly 400 acres slated for redevelopment in the Anacostia Waterfront Planning Area in Washington, D.C. The project team is partnering with federal, national and local agencies and stakeholders to develop and disseminate the results of this project so that other urban areas in the U.S. can take advantage of this sustainable planning tool.