What Is Stormwater?

Stormwater refers to a heavy quantity of water, such as rain or snow, that falls to the surface of the Earth. When it reaches the surface, stormwater becomes polluted as it picks up, carries, and transports various pollutants (oil, grease, chemicals, sediment, nutrients, pathogens) along streets, drains, open channels, and storm sewer systems.

When it reaches the surface, stormwater becomes polluted as it picks up, carries, and transports various pollutants (oil, grease, chemicals, sediment, nutrients, pathogens) along streets, drains, open channels, and storm sewer systems. Most of the untreated runoff eventually is discharged into nearby water bodies. However, in combined sewer systems, stormwater flows with wastewater and is treated at a water resource recovery facility.

In urban areas, stormwater management is especially important because of decreases in natural land cover and the expansion of impervious surfaces, such as rooftops, sidewalks and roadways. These surfaces exacerbate runoff because they change the permeability of the landscape — preventing rainwater from soaking in or infiltrating the soil. Some of the impacts of stormwater include flooding, sewer overflows, and non-point source pollution.

Stormwater is managed using storm sewers as well as stormwater controls, which include green infrastructure and low-impact development.

Join the discussion about stormwater issues on WEF's LinkedIn Stormwater and Watershed Group. You can also follow us on Twitter at @WEFstormwater.

Visit the Stormwater Report Website

Opportunities for Involvement

Stormwater Community
WEF staff contact: Lisa Deason
ldeason@wef.org

OTHER STORMWATER INITIATIVES

WEF Stormwater Institute

The WEF Stormwater Institute is a center for excellence and innovation focused on developing best-in-class solutions to stormwater runoff and wet weather issues. The institute is able to draw from the broad diversity, expertise, and engagement of the WEF membership, which is the largest and most informed clean-water-solutions membership in the world. The institute is identifying cross-cutting issues, convening experts to tackle those issues, providing insights and leadership to policymakers, and helping chart a new course toward a healthier and more sustainable stormwater system in the U.S. and beyond.

To learn more about the Stormwater Institute, visit http://wefstormwaterinstitute.org/.

National MS4 Needs Assessment Survey

The WEF Stormwater Institute has completed two iterations of the National Municipal Separate Storm Sewer System (MS4) Needs Assessment Survey – the first in 2018 and the second in 2020. The primary objectives of these surveys are

• to better understand MS4 program challenges,
• to identify the information and resource needs of MS4 permit holders, and
• to approximate current funding levels and estimated funding needs in the MS4 sector.

To learn more, visit the WEF's Stormwater Institute website.

National Municipal Stormwater and Green Infrastructure Awards

The National Municipal Stormwater and Green Infrastructure Awards program, led by the WEF through a cooperative agreement with the U.S. Environmental Protection Agency, was established in 2015 to recognize high-performing regulated Municipal Separate Stormwater Sewer Programs (MS4s). Now, hosted by WEF, the objective of this program is to inspire MS4 program leaders to seek new and innovative ways to meet and exceed regulatory requirements in a manner that is both technically effective and financially efficient. Recognition of innovative approaches is also a highlight of this program. For more information, click here.

Stormwater Currency

With funding from the Great Lakes Protection Fund – WEF, American Rivers, and Corona Environmental Consulting are working in two U.S. Great Lakes communities on two different financing approaches for green infrastructure implementation. One is with the City of Grand Rapids, Michigan to develop a stormwater credit trading program. The other is with the Northeast Ohio Regional Sewer District to optimize its existing Green Infrastructure Grant Program.

For more information, visit the Stormwater Currency website, watch the WEF webcast recording, listen to the Words on Water podcast, or download the Establishing a Stormwater Volume Credit Trading Program - A Practical Guide for Stormwater Practitioners.