Mercer Island hearing examines setback deviation and reasonable‑use exception for Baumann property

A Mercer Island hearing examiner on Sept. 26 heard testimony on two related land‑use requests that would allow Tim and Kathy Baumann to demolish a legally nonconforming 1,830‑square‑foot house and build a new single‑family residence on a lot largely encumbered by wetland and watercourse setbacks.

The applicants requested a front‑yard setback deviation that would reduce the standard 20‑foot requirement to 10 feet and a reasonable‑use exception (RUE) from critical‑area rules. Regan McClellan, an architect with McClellan Talone Architects, said those changes are necessary because wetland and watercourse buffers, steep‑slope constraints and an access easement cover essentially the entire buildable area.

"The critical areas and setbacks cover 90% of the site and 100% of the buildable area, making the site unbuildable without a zoning exception," McClellan said, describing the parcel as "odd shaped" and crossed by an access easement and buried piped watercourse. He said the piped watercourse is buried 8 to 13 feet below the surface and that exposing it would require an excavation too large for the lot.

Why this matters: the site sits adjacent to off‑site wetlands and a Type F watercourse whose buffers extend over the property. How the city balances protecting those critical areas against an owner’s ability to use land is the central question in RUE hearings; decisions establish whether the applicant can rebuild and, if so, what mitigation and conditions are required.

Applicant’s case and mitigation offer

McClellan and the…