You are here: Home » Community » Environment » Water Quality/Seaport » Stormwater/Seaport
Frequently Asked Questions | Tenant Information | Resource Center | Municipal Permits |
Stormwater is the flow of water that is generated by precipitation and runoff from land, pavements, building rooftops and other surfaces. These hardened surfaces are called ‘impervious surfaces' and they do not allow rainfall to infiltrate into the soil surface like natural vegetation, so more of the rainfall becomes stormwater runoff.
Runoff from impervious surfaces can carry pollutants such as oil and grease, chemicals, nutrients, metals and bacteria. Left untreated, these pollutants will travel through the stormwater system and eventually discharge into Puget Sound . Increased stormwater runoff can also cause erosion of stream banks and flooding.
The management of stormwater is a crucial part of the Port of Seattle's responsibility in protecting the Puget Sound. Covering 1,560 acres, the Seaport's paved surfaces are more than 20 times larger than Seattle Center and almost twice the size of New York's famed Central Park . These surfaces require the Port to manage 1.2 billion gallons of runoff annually.
The Port of Seattle works closely with the Washington State Department of Ecology and our tenants to minimize the impact of stormwater runoff on local waters and their habitat. The Washington State Department of Ecology regulates discharges of stormwater runoff through a permitting process.
The Seaport operates under a Phase I National Pollutant Discharge Elimination System (NPDES) General Permit for Municipal Stormwater, issued by the Washington State Department of Ecology under the Federal Clean Water Act (CWA). Phase I Permits apply to municipalities with populations of 100,000 or more, and to agencies located within the municipality. The Phase I Permit establishes a framework for controlling pollutants from stormwater runoff to the maximum practical extent. Its goal is restoring and maintaining the chemical, physical and biological integrity of our region's waters including rivers, streams, lakes, wetlands, and marine waters.
Most of the Seaport's property is leased to commercial and industrial tenants. Approximately 70 percent of these properties are covered by a General Industrial NPDES stormwater permit rather than the Phase I Permit.
This page provides a location for Port tenants to access pertinent policies, documents and links. It contains information about regulatory compliance requirements (Stormwater Pollution Prevention Plans, or SWPPPs), City of Seattle municipal permit requirements, and required construction practices (Best Management Practices, or BMPs). Seaport Division property maps show the type and location of different permit holders. Information on Low Impact Development (LID) options for stormwater management and the Seaport Division's new Illicit Detection and Discharge Elimination (IDDE) Program is also included.
The online Stormwater Resource Center offers a centralized location to access additional information regarding stormwater topics. Links to stormwater code, manuals, maps, and additional online resources are available for Port employees, tenants and the interested public.
;){kind=link}