Covington staff, planning commission recommend wider stream buffers and clearer CAO exemptions

Covington city staff and the Planning Commission reviewed a proposed update to the city's Critical Areas Ordinance that would widen stream buffers and add new, limited exemptions for small-scale yard work.

The update is intended to align Covington's code with state guidance under the Growth Management Act and best-available-science documents adopted with the city's recent comprehensive plan, staff said. The Planning Commission recommended measuring stream buffers using a riparian management zone (RMZ) approach and increasing the buffer for fish-bearing streams from 115 feet to 125 feet.

Why it matters: state law requires local codes to avoid a 'no net loss' of ecological functions and values for critical areas. City staff and consultant biologists said recent state guidance from the Department of Ecology and the Washington Department of Fish and Wildlife tightens expectations for stream protection, and the CAO update is meant to bring Covington into compliance and modernize the code for users.

The presentation focused on two measurement methods. The RMZ sets a static, tiered buffer by stream type; the site-potential tree height (SPTH) approach calculates buffer width from the predicted mature height of dominant riparian trees. Staff said…