Improving management of stormwater so that water quality, habitat and aquatic resources are protected is one of eight key objectives established in law for the Puget Sound Partnership’s 2020 Action Agenda.  

What’s the problem?

Rain is a part of life in the Pacific Northwest . Stormwater runoff is rain (or snowmelt) that flows off developed land—such as roads, parking areas, rooftops and lawns—into nearby streams, rivers and Puget Sound . Runoff enters these waterbodies either directly or through drainage systems.

Stormwater runoff poses a high risk to the health of Puget Sound by causing two major problems.

First, stormwater transports a mixture of pollutants such as petroleum products, heavy metals, animal waste and sediments from construction sites, roads, highways, parking lots, lawns and other developed lands, with the following results:

  • Stormwater pollution has harmed virtually all urban creeks, streams and rivers in Washington State .
  • Stormwater is the leading contributor to water quality pollution of urban waterways in the state.
  • Two species of salmon and bull tout are threatened with extinction under the federal Endangered Species Act. Loss of habitat due to stormwater and development is one of the causes.
  • Shellfish harvest at many beaches is restricted or prohibited due to pollution. Stormwater runoff is often one of the causes.
  • Stormwater likely contributes to the killing of high percentages of healthy coho salmon in Seattle creeks within hours of the fish entering the creeks, before the fish are able to spawn.
  • English sole are more likely to develop cancerous lesions on their livers in more urban areas. Stormwater likely plays a role.
Second, during the wet, winter months, high stormwater flows, especially long-lasting high flows, can:
  • Cause flooding.
  • Damage property.
  • Harm and render unusable fish and wildlife habitat by eroding stream banks, widening stream channels, depositing excessive sediment and altering natural streams and wetlands.

In addition, more impervious surface area means less water soaks into the ground. As a result, drinking water supplies are not replenished and streams and wetlands are not recharged. This can lead to water shortages for people and inadequate stream flows and wetland water levels for fish and other wildlife.

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What’s being done?

Efforts to more effectively manage stormwater are happening throughout the region, and have been happening for many years. This work involves state, local and federal agencies, tribes, non-profit organizations, citizen groups, businesses and many others.

Low impact development (LID) is a set of stormwater management practices that hold great promise for improving the way we develop land and manage stormwater. Our region has its own design guidance manual, the Low Impact Development Technical Guidance Manual for Puget Sound. The Partnership, in concert with WSU Pierce County Extension and numerous regional partners, plans to update this manual in 2009. Since 2000, the Partnership and many regional partners have led efforts to promote the use of LID in the region.

 Highlights of work underway:

 Cities and counties

  • Local governments are on the front lines managing land development and stormwater runoff. They develop local land use plans, determine zoning and urban growth areas, identify and protect critical areas, review development proposals, run stormwater programs, and more. Many cities and counties have developed strong, stable programs while others need to improve significantly.
  • Local governments also are working to reduce combined sewer overflows (CSO)—the mixing of raw sewage and stormwater. All municipalities with CSOs are carrying out a reduction plan that’s been approved by the Department of Ecology. Primary reduction methods include physically separating combined sewer and stormwater lines, and/or storing excess stormwater during heavy rains.  
Washington state agencies
  • The Department of Ecology provides guidance; issues federally-mandated permits for more urban municipalities, industries and construction sites larger than one acre and highway runoff; and provides technical and financial assistance. Once the new federally mandated municipal permit (NPDES phase II) is in place, the majority of the population in western Washington will be covered by the permit, providing much greater consistency for stormwater management.
  • In the 2007-09 biennium, Ecology has approximately $25 million in new funds to help local governments improve stormwater management efforts. Ecology also issues and oversees the permit governing highway runoff management for the Washington Department of Transportation.
  • Washington Department of Transportation works to ensure that new highway construction projects control sediment and erosion, and include controls for treatment and flows. The department also carries out projects to retrofit existing systems as funds are made available by the legislature; provides training for contractors; and carries out research.
  • Washington Department of Health, the Partnership and Ecology are working to upgrade shellfish growing areas that are threatened by or closed due to stormwater runoff.
Collaborative work
  • The Partnership is working with local governments to revise existing and develop new regulations and development standards to allow for or encourage the use of LID techniques. The Partnership will be providing additional training on LID during 2007-09. 
    >> Learn more about the Puget Sound Partnership’s work on low impact development

  • The Partnership, working with Ecology, water quality field agents from Washington State University and University of Washington, provide education and technical assistance to local communities to help them develop effective comprehensive stormwater management programs that include land-use planning, watershed planning and salmon recovery efforts.
  • Washington State Conservation Commission (WSCC) and WSU Extension are assisting private, small-acreage landowners in reducing contamination from and the volume of stormwater runoff. WSCC will also help small-acreage landowners in using best management practices on their properties to manage stormwater runoff.
  • WSU Extension staff educate homeowners, vehicle owners, real estate professionals, developers and state, tribal and local governments with the goal of providing them with the skills and motivation to change practices to reduce the harm from stormwater runoff.
  • The University of Washington and Washington State University carry out research, educate, and provide professional training. The University of Washington’s Engineering Professional Program offers LID training sessions once or twice each year.


  • Tribes and federal offices manage runoff from lands under their authority. In addition, U.S. EPA Region 10 provides funding for many projects, such as LID local regulatory assistance. NOAA Fisheries provides valuable research on the effects of urban development on aquatic resources. 


 >> Learn more about efforts to improve stormwater management in the Puget Sound Basin in the 2007-2009 Puget Sound Conservation and Recovery Plan.

>> What you can do to help better manage and reduce stormwater

 >> Learn more / Get resources about stormwater

For more information about the Puget Sound Partnership ’s work on stormwater management, contact Bruce Wulkan, 360.725.5455.

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