Stormwater Management

In This Section

Background

Stormwater is rainwater and melted snow that runs off streets, lawns, farms, and construction and industrial sites. Under natural conditions, stormwater is absorbed into the ground, where it is filtered and ultimately replenishes aquifers or slowly flows through forests and meadows into streams and rivers. In developed areas, however, impervious surfaces such as pavement and building roofs prevent precipitation from naturally soaking into the ground. Instead, the water runs rapidly into storm drains, sewer systems, and drainage ditches. The resulting rush of stormwater discharge can cause downstream flooding and erode stream banks. In addition, the bacteria and other pollutants not filtered from stormwater can contaminate watersheds and coastal waters. Stormwater management addresses these concerns through a variety of techniques, including strategic site design, measures to control the sources of runoff, and thoughtful landscape planning.

With the implementation of the Energy Independence and Security Act of 2007 (EISA), effective stormwater management techniques are becoming increasingly relevant to federal agencies. EISA requires federal agencies to maintain or restore a site’s predevelopment hydrology when developing or redeveloping more than 5,000 square feet of outdoor space. Agencies can use stormwater management techniques, such as those incorporated by EPA, to meet this requirement.