Edmonds staff outline major critical-areas code rewrite; riparian zones to widen under new science

Planning staff told the council on Oct. 28 that Edmonds is undertaking a periodic update to the city's critical-areas ordinance (CAO), citing state requirements for a decennial review and newly released best-available science from Washington Department of Fish and Wildlife.

Brad Shipley described how the update replaces the simpler concept of fixed stream "buffers" with a broader riparian management zone (RMZ) approach that considers vegetation, shade, nutrient inputs and holistic stream health. For fish-bearing streams staff said a 200-foot RMZ was the reference used in the updated guidance; where streams do not support fish staff said a 100-foot RMZ will deliver roughly 90'295% of the targeted filtration and shading benefits used to protect aquatic habitat. For redevelopment proposals the code would continue to allow rebuilding within an existing footprint in most cases; staff proposed an option to permit a 25% RMZ reduction when applicants provide a riparian enhancement plan tied to native plantings and improvements.

Shipley also described a large reorganization of Title 23 to consolidate six chapters into a single critical-areas chapter, reduce redundancy, and add updated definitions. Staff recommended new implementation tools including a checklist for critical-area reports, a public-facing decision flowchart, and an annual monitoring and adaptive-management report that sets metrics and review steps.

Council questions focused on likely maps, watershed-specific treatment (Perronville and Shell creeks were discussed), the timing of future staff reports, and how the CAO changes would coordinate with stormwater planning. Staff said maps of RMZs across the city exist and will be shared with council and noted that further watershed planning and coordination with stormwater engineering will be important next steps.

What happened next: Council accepted the introduction and asked staff to post maps and develop the report/checklist materials; no final CAO adoption occurred Oct. 28.

Why it matters: The proposed changes implement updated science and will expand the geographic scope of critical-area regulation in some places, with implications for property redevelopment, permit review, and restoration opportunities across Edmonds' streams and riparian corridors.