Stormwater Management Program

This Stormwater Management Program (SWMP) describes King County's proposed actions to comply with the National Pollutant Discharge Elimination System (NPDES) phase I municipal stormwater permit issued by the Washington State Department of Ecology (Ecology) on Jan. 16, 2007. The SWMP's primary focus is the compliance activities proposed for 2009.  The 2009 document was submitted to the Washington State Department of Ecology on March 31, 2009.

King County 2009 stormwater management program (SWMP)  (Acrobat pdf, 1.6 MB)

More Information

The permit affects King County in multiple areas:

• As the local land use authority for the unincorporated area, King County must have appropriate codes, regulations, and enforcement and education capacity to reduce water-polluting practices and to increase or promote practices that protect water quality.
• As a landowner and property manager, King County must ensure that its own practices meet the regulatory standards we have set.
• As a local government that strives to protect the environment, King County must embark on a monitoring program that identifies stormwater pollutants and the effectiveness of commonly used best management practices (BMPs), in addition to studying program challenges with the goal of finding more effective, affordable management practices.
• As a regional government, King County must work at an unprecedented level of coordination with other municipalities, and among the many departments, divisions and sections within county government.

King County must increase its efforts in a number of program areas to comply with the permit:

• Mapping - Specific schedules must be met for completing various components of the separate storm sewer mapping. Under the previous permit, ongoing mapping with no well-defined deadlines was acceptable.
• Coordination - A written intra-governmental coordination agreement or order is required, in addition to intergovernmental coordination mechanisms. Under the previous permit, coordination was required, but not defined.
• Public involvement - Each year the SWMP will be updated, and the public must have an opportunity for a meaningful role in its development and implementation. Under the previous permit, the SWMP covered the entire permit term, and public involvement was required only during the initial development process.
• Controlling runoff from new development, redevelopment and construction sites - King County must use drainage design and source control rules equivalent to those in Ecology's 2005 manual and must meet newly established standards for staff training and inspections. The previous permit required equivalency with the 1992 Ecology manual and didn't set standards for staff training and inspections. Under the new permit, all King County development projects, even those located in other jurisdictions, must comply with the county's equivalent manual if it is more stringent than that of the jurisdiction in which the development is occurring.
• Structural stormwater controls - More detail is required about the goals of capital projects aimed at reducing the quantity and quality impacts of stormwater from past, present and future land development and the estimated benefits of those projects must be quantified.
• Source control program for existing development - The source control best management practices used by King County must be equivalent to those in Ecology's 2005 manual, and standards for staff training are set. The new permit also requires a much more aggressive program for identifying and inspecting pollution-generating sites.
• Illicit Connections and Illicit Discharges Detection and Elimination (IDDE) - More stringent water quality codes are required, staff training standards are set, and a more aggressive program required, with enforcement timelines.
• Operation and Maintenance Program - Maintenance standards must be equal to those in the 2005 Ecology manual and standards must be developed for practices that are not covered. Rigorous maintenance schedules and cleaning standards are required, and stormwater pollution prevention plans (SWPPPs) are now required for sites that did not previously need them. Staff training standards are established.
• Education and Outreach Program - Target audiences and topics are specified, along with a requirement to attempt to measure program effectiveness and work regionally. The previous permit required only the existence of a program.

The 2007 permit also requires a monitoring program that will be used to identify pollutants in stormwater and the effectiveness of commonly used control facilities, and to provide ideas for improving stormwater management. The 2007 permit's annual reporting requirement is much more standardized and specific than the previous permit's requirements.

Nearly all sectors of King County government will be participating in the new SWMP.

• The Water and Land Resources Division is charged with coordinating the SWMP and annual reporting. Additionally, WLRD manages the coordination, public involvement, manual equivalency, structural stormwater control, and public education portions of the SWMP, and has a significant role in King County's source control, IDDE, and operations and maintenance programs. WLRD will be designing and conducting much of the training that is required, including training for some of its own staff.
• Many divisions manage and develop properties and facilities that are not covered under other National Pollution Discharge Elimination System permits. These divisions include Wastewater Treatment, Solid Waste, Parks, Roads Maintenance, Transit, the King County International Airport, Facilities Maintenance and the Sheriff's Office. Drainage facilities on those lands must be mapped, designed, and maintained in a manner consistent with permit requirements and King County's source control BMPs for pollutant-generating activities must be used. Some staff training requirements also apply. SWPPPs must be prepared. The Roads Maintenance Division also leads the mapping program and will partner with WLRD on developing required training.
• The Department of Development and Environmental Services is responsible for ensuring the equivalent manual requirements are applied to new and re-development. For King County, this action includes not just the Surface Water Design and Stormwater Pollution Prevention manuals, but also related codes, which are applied to new and re-development within the confines of state vesting law.
• Public Health - Seattle & King County's wastewater program has oversight of onsite sewage systems throughout King County. Corrective actions are taken where there is evidence indicating failing onsite systems are introducing contaminants into stormwater systems. In addition, Public Health regulates and inspects a variety of businesses located throughout the county, and can identify potential illicit discharges or connections to the stormwater system.

The increases in effort necessary in 2008 for permit compliance have been budgeted and are proceeding as described. However, future increases in required effort have not yet been budgeted and will be particularly challenging as King County's fee and tax revenues decline as a result of planned annexations of urban areas. Although the need for King County to provide permit-required services in these areas will be eliminated, the loss in service costs is typically less than the loss in revenue collected. This is because only a portion of the service costs are for direct services to specific areas - many costs, such as those for SWMP tracking, updating, and reporting; coordination; public involvement; updating regulations; monitoring, etc. apply to the municipality as a whole, regardless of size.

And, while King County's unincorporated area will become more rural as planned annexations occur, it will still retain some higher density areas that require urban levels of service because there are high density areas that are not currently planned for annexation and medium density areas now zoned rural that are not eligible for annexation. Consequently, there will continue to be a need to fund the more traditional stormwater management services required by the permit. In addition, as single lot and lower density subdivision development continues in the rural area, there will be an overall increase in more non-traditional stormwater controls. These include forest retention and other low impact development techniques, such as flow dispersion and reduced impervious surface. These new features will require periodic inspection by King County to ensure new types of controls are maintained and so will add to the challenges of future funding for permit compliance.

Water and Land Resources Division plans to revise its business plan in 2008 to address these future challenges in funding permit compliance and other water and land protection needs.