Implement Stormwater Best Management Practices (BMPs) to Prevent Pollution, Erosion, and Flooding

Best Management Practices (BMPs) include a variety of operational and structural measures that reduce stormwater pollution and improve the quality of our water resources. All private property owners, whether commercial, multifamily, or residential, are required to implement and maintain BMPs to reduce the pollution leaving their property. This pollution eventually makes its way into local waterbodies such as wetlands, streams, and lakes.

There are two broad categories of BMPs:

• Source Control BMPs prevent contaminants from ever entering stormwater by using both operational and structural BMPs.
• Treatment BMPs treat polluted stormwater to remove contaminants. However, since no treatment BMP can remove all contaminants, it is more effective to prevent pollution at its source than it is to treat it.

Ultimately, a combination of both source control and treatment BMPs work together to get maximum water quality benefits.

Source Control BMPs

For property owners, the simplest and most cost-effective BMPs are operational (nonstructural) source control BMPs, such as:

Checking regularly for leaks and drips from equipment and vehicles;

• Keeping a spill kit onsite;
• Keeping dumpster lids closed;
• Sweeping parking lots instead of washing pollution into storm drains;
• Cleaning up pet waste; and
• Minimizing the use of pesticides, fertilizers, and insecticides.

Structural source control BMPs use a structure to prevent rainwater from contacting materials that will contaminate stormwater runoff. For example, building a covered containment area or a berm prevents clean stormwater from entering work or storage areas and getting polluted in the process. Structural source control BMPs may require a building permit and more capital expenditures.

Treatment BMPs

Treatment BMPs, such as swales, stormwater ponds, and permeable pavement, typically need elaborate planning, engineering design, and construction. This takes place during the development process. Most of the time, property owners won’t need to add treatment BMPs on their own. Though, it could be needed if operational BMPs aren’t reducing pollution enough. Property owners must regularly maintain treatment BMPs within their property to make sure they continue to work as they should.

More Stormwater BMP Resources:

For more detailed information and BMP activity sheets, please see:

• 2021 King County Pollution Prevention Manual
• City of Kent Surface Water Design Manual
• City of Kent Design and Construction Standards
  

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