Critical Areas Ordinance

The Metropolitan King County Council on October 25, 2004, approved the Critical Areas package: three pieces of legislation that will help protect land in unincorporated King County from flooding and erosion coming from neighboring properties and protect groundwater and wildlife habitat, and ensure that urban areas do their part to protect water quality and wetlands.

Read the final adopted ordinances as Acrobat pdf files:

Ordinance 15051: Critical Areas [261 pgs, 679K pdf]

Attachment A: King County Basin and Shoreline Conditions Map [1.3 MB pdf]

Attachment B: King County Critical Aquifer Recharge Areas Map [2.9 MB pdf]

Ordinance 15052: Stormwater [39 pgs, 125K pdf]

Ordinance 15053: Clearing and Grading [76 pgs, 214K pdf]

Critical Areas include both hazardous areas (such as floodplains and steep slopes) and environmentally sensitive areas (like wetlands and streams). Critical areas also include areas that are important for protecting groundwater. The Stormwater Ordinance sets standards for preventing flooding and erosion that can result from new development and affect neighboring properties. It also includes requirements for preventing pollution of streams, lakes, and other water bodies. The Clearing and Grading Ordinance outlines requirements for preventing erosion from new development, land clearing, and grading. King County has had regulations dealing with critical areas, stormwater, and clearing and grading for more than a decade. These three ordinances amend existing requirements.

The Council made significant changes to the Critical Areas package that was transmitted to the Council for review in early March. Among the key amendments:

Wetland Buffers: Rather than a “one size fits all” approach that applies buffer widths based only on wetland category, the Council adopted an approach that considers both the intensity of land uses around the wetland and on-the-ground habitat conditions. The Council also amended the buffers to ensure that both urban and rural areas do their part to protect wetlands. Buffers for all areas of unincorporated King County use guidance from the Department of Ecology as a starting point. The result is that buffers in the rural area are generally smaller than under the Executive Proposal to reflect the lower density land uses in the rural area. Buffers in the urban area are larger than what is on the books today.

Wetland Mitigation Ratios: When a development impact to a wetland cannot be avoided, mitigation is required. The Council has amended the county’s wetland mitigation ratios to be consistent with guidance from federal and state agencies. This ensures that King County’s requirements are harmonized with federal and state agencies, and that applicants won’t get “caught in the middle” between regulatory agencies.

Clearing Limits: Prior to the adoption of these ordinances, limits on permanent land clearing applied in certain stream basins (including Bear, Issaquah, Soos, May Creek Basins). The Executive Proposal included application of a 35% clearing limit throughout the rural area. Under the amended ordinance adopted by the Council:

Pastures and other areas cleared in prior years are “grandfathered” to ensure that people can continue to keep livestock.

The clearing limits are scaled to lot size (for example, the clearing limit is 50% for a 5-acre parcel) to provide additional flexibility on traditional rural activities. The exception is where stricter clearing limits have already been put in place as part of a detailed, local study.

Landowners can get additional flexibility on clearing limits through a Farm Plan or Rural Stewardship Plan.

Based on public testimony, the Council made several clarifications regarding how the clearing limit would apply to past set asides and utilities:

Areas set aside in tracts through past development (for example, a “critical areas tract” set aside as part of a past subdivision), will be recognized as forested areas for the purposes of the clearing limits.
Areas required to remain cleared as part of a utility or public road easement will not “count” toward the clearing limits.
On lots smaller than 1.25 acres, clearing for utilities, septic, and access also does not “count” toward clearing limits.

Emphasis on Handling Stormwater Impacts on Site: The Council eliminated the “10% impacting impervious surface limit” in favor of greater emphasis on stormwater best management practices that disperse and infiltrate groundwater on site to prevent flooding of neighboring properties and protect groundwater.

Treatment of Recorded Short Plats: The Council clarified that for short plats, the critical areas, stormwater, and clearing and grading requirements in effect at time of short plat application will apply for 5 years after recording.

You can read a more detailed Summary of Council Review and Key Changes, and get answers to Frequently Asked Questions.

More Information

For about specific CAO provisions and the permitting process, please contact the Department of Development of Environmental Services (DDES) at 206-296-6600.

For additional CAO-related information, fact sheets, and resources, please go to www.metrokc.gov/cao.

For individual lots, the Council eliminated the requirement to record clearing limits on the property title.

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