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Stormwater Management
In This Section
Stormwater is rainwater and melted snow that runs off streets, lawns, and other sites. When stormwater is absorbed into the ground, it is filtered and ultimately replenishes aquifers or flows into streams and rivers. In developed areas, however, impervious surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, the water runs rapidly into storm drains, sewer systems, and drainage ditches and can cause:
- Downstream flooding
- Stream bank erosion
- Increased turbidity (muddiness created by stirred up sediment) from erosion
- Habitat destruction
- Changes in the stream flow hydrograph (a graph that displays the flow rate of a stream over a period of time)
- Combined sewer overflows
- Infrastructure damage
- Contaminated streams, rivers, and coastal water
Stream bed and channel erosion from stormwater flow. Source: www.mvk.usace.army.mil
Why Manage Stormwater?
Traditional stormwater management design has been focused on collecting stormwater in piped networks and transporting it off site as quickly as possible, either directly to a stream or river, to a large stormwater management facility (basin), or to a combined sewer system flowing to a wastewater treatment plant.
Low impact development (LID) and wet weather green infrastructure address these concerns through a variety of techniques, including strategic site design, measures to control the sources of runoff, and thoughtful landscape planning.
LID aims to restore natural watershed functions through small-scale treatment at the source of runoff. The goal is to design a hydrologically functional site that mimics predevelopment conditions.
Wet weather green infrastructure encompasses approaches and technologies to infiltrate, evapotranspire, capture, and reuse stormwater to maintain or restore natural hydrologies.
Federal Stormwater Management Requirements and Guidance
At facilities across the country, EPA has long employed a full spectrum of stormwater management practices to reduce the impact of Agency activities on the hydrology of local watersheds. EPA's stormwater management efforts continue in accordance with the new paradigms and requirements set out in Executive Order (EO) 13514, signed in October 2009, the Energy Independence and Security Act of 2007 (EISA), and EO 13423.
EPA Facilities and Stormwater Management
EPA's approach to stormwater management is driven by internal goals and federal requirements. EPA has developed strategies that guide the stormwater-related actions EPA takes and help produce results such as reductions in site runoff volumes and improved stormwater quality. Learn more about stormwater management.