Source Control Best Management Practices
The Department of Ecology Stormwater Management Manual for Western Washington defines a source control best management practice (BMP) as “a structure or operation intended to prevent pollutants from coming into contact with stormwater through physical separation of areas or careful management of activities that are sources of pollutants.”
Source control BMPs are separated into two types:
- Structural Source Control BMPs are physical, structural, or mechanical devices or facilities that are intended to prevent pollutants from entering stormwater.
- Operational Source Control BMPs are non-structural practices that prevent or reduce pollutants from entering stormwater.
Applicable operational source control BMPs are required for all pollutant generating sources. Structural source control BMPs, or treatment BMPs/facilities, or both, shall be required for pollutant generating sources if operational source control BMPs do not prevent illicit discharges or violations of surface water, groundwater, or sediment management standards.
Source Control Best Managment Practices can be found in Volume IV of the Stormwater Managment Manual for Western Washington
Selecting Source Control BMPs
For sites that must implement Source Control BMPs, use the following steps to guide selection of appropriate Source Control BMPs:
- All sites must implement the Source Control BMPs listed in IV-1 Source Control BMPs Applicable to All Sites.
- Next, base selection of additional Source Control BMPs on land use and the pollutant generating sources at the site.
- Use Appendix IV-A: Urban Land Uses and Pollutant Generating Sourcesto help determine activities and the potential pollutant generating sources associated with those activities for various land uses.
- Applicable operational and structural Source Control BMPs for each pollutant source can then be selected by reviewing the BMPs in Volume IV, which are categorized by activity. Land uses not included in Appendix IV-A: Urban Land Uses and Pollutant Generating Sources should also consider implementing Source Control BMPs for their pollutant sources.
For example, if a commercial printing business conducts weed control with herbicides, loading and unloading of materials, and vehicle washing, it should refer to the following BMP sections for these activities:
- S411 BMPs for Landscaping and Lawn / Vegetation Management
- S412 BMPs for Loading and Unloading Areas for Liquid or Solid Material
- S431 BMPs for Washing and Steam Cleaning Vehicles / Equipment / Building Structures
- S404 BMPs for Commercial Printing Operations
- Within the text for each Source Control BMP, there are “applicable” and “recommended” BMPs listed.
The reader should interpret the term “applicable” when referring to specific operational or structural Source Control BMPs as meaning “mandatory” or “required”. These BMPs must be implemented at the site.
Ecology offers “recommended” Source Control BMPs as approaches that go beyond or complement the applicable (mandatory) BMPs. Implementing the recommended Source Control BMPs may improve control of pollutants and provide a more comprehensive and environmentally effective stormwater management program. Ecology encourages all operators to review their SWPPPs and use recommended BMPs where possible.