Green Infrastructure and Low Impact Development

Overview

The goal of green infrastructure and low impact development practices is to develop land and manage stormwater in a manner that imitates the natural hydrology. In a mature forest setting, nearly all the precipitation disperses along the forest floor, where it infiltrates into the ground. It is soaked up by the roots of plants and trees, or evaporates. Researchers estimate that about one percent becomes surface runoff. When forests and natural open spaces are cleared, and buildings, roads, parking areas and lawns dominate the landscape, rainfall becomes stormwater runoff, carrying pollutants to nearby waters. Much less water infiltrates than is soaked up by plants, less evaporates back to the atmsophere, and more becomes surface runoff.

What Are the Benefits of Green Infrastructure and LID Practices?

1. Can help protect the environment
   LID and green infrastructure techniques remove pollutants from stormwater, reduce the overall volume of stormwater, manage high storm flows, and replenish streams and wetlands.

2. May reduce flooding and protect property
   Reducing impervious surfaces, increasing vegetation and dispersing and infiltrating stormwater results in less runoff. This reduces the likelihood of flooding from large rain events.

3. Helps protect human health by more effectively removing pollutants from stormwater
   Untreated stormwater can be unsafe for drinking and swimming.

4. Protects drinking water supplies
   ...by ensuring that rainfall infiltrates and recharge aquifers, rather than being treated as a wastewater.

5. Provides cost-effective alternatives to systems upgrades
   Land developed prior to the 1990's usually provided little, if any, stormwater treatment. In many cases, green infrastructure and LID systems are much less expensive than costly stormwater vaults or land-consuming stormwater ponds.

6. Can increase the appearance and aesthetics of communities
   LID and green infrastructure projects leave more trees and plants and have less impervious surfaces, which makes for greener developments and communities.

7. Can increase public safety One of the hallmarks of these practices is more narrow streets. Studies show that when vehicle traffic is slowed, there are fewer pedestrian accidents and fatalities.

8. Is good for the economy Green infrastructure can help protect our natural resources, water quality and reduce sediment loads. This ensures that our resources remain clean and our watersheds remain a great place to operate a business and attract employees. If our rivers and streams are clean, taxpayers don’t have to bear the burden of expensive cleanup efforts for polluted waters.

Additional Resources

• Green Infrastructure

  Green infrastructure (GI) is a network of decentralized stormwater management practices, such as green roofs, trees, rain gardens and permeable pavement, that can capture and infiltrate rain where it falls, thus reducing stormwater runoff and improving the health of surrounding waterway.

• Construction Indu​stry Compliance Assistance Center

  CICA is your source for plain language explanations of environmental rules for the construction industry.

• Low Impact D​evelopment (LID) Center

  We are a non-profit national research organization that focuses on sustainable stormwater management solutions for urban and developing areas.

• LID Urban Design Tools

  This site provides watershed managers with a new set of tools and techniques that can be used to meet regulatory and receiving water protection program goals for urban retrofits, re-development projects, and new development sites.

• EPA: Green Infrastructure

  Many communities are installing green infrastructure systems to bolster their capacity to manage stormwater. By doing so, communities are becoming more resilient and achieving environmental, social and economic benefits.

• EPA: Watershed Academy

  The Watershed Academy provides self-paced training modules and webcasts from national experts about a range of watershed management topics.

• Rain Gardens

  Bioretention and infiltration practices come in a variety of types and scales, including rain gardens, bioswales and wetlands.​