Mercer Island commission advances draft park-zone rules covering signs, trails, scoreboards and impervious-surface limits

Park and Recreation Commission members spent the bulk of their Feb. 6 meeting reviewing a draft Park Zone code intended to align park-specific development standards with existing park uses and citywide rules.

The commission heard staff present proposed rules covering multiple topics: how wireless communications facilities would be treated; setback and signage limits; standards for scoreboards, kiosks and picnic shelters; a proposed 12-foot maximum for trail widths; guidance (not numeric minimums) on parking; a “no net new” impervious-surface approach with listed exemptions; and lighting requirements framed around shielding and industry-recommended levels.

Staff said wireless communications are already regulated elsewhere in Mercer Island’s municipal code and by state and federal law, and recommended including wireless facilities as a permitted use in the Park Zone with design-and-concealment language like the city’s Open Space Zone. City staff warned that excluding wireless as a permitted use could create conflicting code provisions and invite appeals, because state and federal rules limit local authority over such deployments.

On setbacks, staff proposed language carried over from the Open Space Zone plus a short list of site features explicitly exempted from a setback requirement (for example, parking areas, bollards, kiosks and utilities); commissioners indicated the exemptions reflect what is already on the ground.

Signage: staff reported many park signs are larger than the 10-square-foot cap used for open space parcels and recommended a limit of 16–18 square feet but placed 18 square feet in the current draft pending a final audit of existing signs. Commissioners asked staff to confirm the largest existing sign size before March. Staff also noted the city’s existing sign code (freestanding/ground sign limits) would apply unless the Park Zone adds a different limit.

Scoreboards: staff said the Island Crest Park scoreboard covers about 200 square feet of surface and proposed an upper limit between about 200 and 220 square feet to avoid creating a single, technically nonconforming scoreboard. Commissioners discussed whether to define a static maximum (e.g., 210–220 sq ft) or rely on a variance process for any future larger scoreboards; staff warned that variances are difficult to obtain for signs and recommended setting a specific cap and allowing case-by-case exceptions.

Kiosks: staff recommended using the existing Pioneer/Luther Burbank model (about 22 square feet surface area; up to 10 feet high) as a system standard.

Trails: staff presented a range of existing trail widths and surface types across the park system and recommended limiting trail development in the Park Zone to a maximum width rather than prescribing materials. After discussion about maintenance and emergency-vehicle needs, the commission indicated support for a 12-foot maximum trail width in the draft code while retaining flexibility for maintenance and official emergency-access corridors.

Picnic shelters: staff proposed using the existing Aubrey Davis shelter as a system standard (maximum 16-foot height, up to 1,200 square feet gross floor area); commissioners agreed to that recommendation.

Parking and access: staff withdrew a universal, per-field parking-minimum and instead proposed that parking be evaluated case-by-case when a proposed use is expected to exceed existing parking capacity. The draft includes standards for parking design, ingress and egress and references the city engineering standards for numeric requirements.

Impervious-surface policy: staff proposed a “no net new impervious surface” rule for park parcels, with a set of exemptions: improvements approved via an adopted master plan, ADA-required accessibility improvements, emergency access needs, public trails, synthetic turf athletic fields and utilities. Commissioners raised practical questions about routine small improvements (benches, small pads) and playground surfacing. Staff agreed to draft clarifying language that would (a) examine whether accessible playground surfacing should be exempted to allow replacing surfacing without forcing a net-new calculation and (b) consider a narrow exemption or threshold for small maintenance‑level features (benches, pads, short concrete bases) so routine work would not be blocked by the net-new rule.

Lighting: staff proposed park lighting rules that require fully shielded fixtures, aim-and-shield practices for sports fields consistent with IESNA guidance, automatic timers and a requirement that sports/field lighting be turned off within 30 minutes after use. Commissioners asked staff to clarify a cross-reference to public-right-of-way lighting (and to ensure the Park Zone rules align with the city’s existing street‑lighting standards); staff will refine the language before the next meeting.

Next steps: staff will return with a revised draft in March that incorporates clarifications on sign size, the playground/impervious exemptions, and lighting cross references. Commissioners indicated they intended to finalize most Park Zone topics at that meeting so the commission can hand a recommended package to city council.