Planning commission reviews proposed critical area ordinance updates, including 100-foot riparian minimum and vegetative buffer standards

City of Bothell staff presented proposed updates to the Critical Areas Ordinance at the Planning Commission study session Sept. 17, outlining a preferred approach that sets a 100‑foot minimum riparian management zone (RMZ) for streams, adds vegetative buffer standards, and recommends raising local SEPA exemption thresholds.

Planner Ray Sosa (carrying the item while colleague Jacqueline Sampson joined remotely) described the proposal as a mandatory CAO update drawing on the city’s best-available-science report and the state agencies’ recommendations. The staff recommendation sets a 100‑foot minimum buffer for all stream types to assure basic water-quality protections; staff explained this reflects Department of Fish and Wildlife minimums while offering predictability for applicants.

Sosa said the Fish and Wildlife and Department of Ecology analyses also describe an alternate approach tied to site-potential tree height, which can produce widely varying buffer distances (examples discussed ranged from roughly 90 feet up to more than 200 feet depending on soils and species). Staff recommended the fixed 100-foot floor because the site-potential approach would create sharp, parcel-level variation that would be difficult for applicants and staff to apply consistently.

Other proposed changes reviewed by staff include: - Adding vegetative buffer standards and carrying those standards across wetland and stream buffers to incentivize native plantings, invasive species removal, restoration and maintenance. - Deleting a variance section because existing code contains other flexibility tools (buffer averaging, reasonable use exceptions). - Adding explicit nonconforming-structure standards so property owners understand what maintenance, repair or limited additions are allowed in a buffer. - Retaining a predictability-first approach while offering incentives (for example, reduced buffer width where a high-quality vegetative buffer is provided).

Commissioners and staff discussed who would bear the cost of any soils/standards analysis if site-potential tree height were used: staff said property owners would be responsible for any site-specific soils or geotechnical work required to claim a smaller or larger site-specific buffer. Commissioner Westerbeck and others supported a simple, predictable 100‑foot minimum to reduce administrative cost and uncertainty; Commissioner Lever asked staff to clarify the developer/owner cost implications.

Staff also proposed raising the city’s SEPA threshold exemptions to levels similar to nearby jurisdictions (the packet referred to the jurisdictional “blue line” example used by Redmond), which would reduce SEPA review for larger projects that can meet the city’s built-in mitigation standards. Staff noted SEPA-exempt projects would still be publicly noticed and subject to city standards and appeals.

Staff told commissioners they will return with written comments from Department of Fish and Wildlife and Ecology and with finalized draft code language for Commission review; they expect to forward an ordinance to City Council in late 2025 for adoption. No formal action or vote was taken by the commission at the Sept. 17 meeting.

Throughout the discussion staff, commissioners and the public distinguished between discussion points (the options and tradeoffs), direction for further work (staff to obtain agency comments and prepare final draft code), and formal decisions (none at this meeting).