Fairfax planning panel approves revocable encroachment for mountain‑bike exit onto Iron Springs Road

The Fairfax Planning Commission on April 17 approved a revocable encroachment permit to allow construction of a short exit trail from Camp Tamarancho onto Iron Springs Road, a project proponents say will remove downhill mountain‑bike traffic from the paved roadway.

The permit authorizes work limited to roughly an eight‑foot segment of the public right‑of‑way that will include a three‑foot retaining wall, a split‑rail fence and a post‑and‑block speed‑reducing gate at the trail terminus. The commission approved the permit 5‑0 and added conditions requiring trail‑crossing signage, four “quiet zone” signs, and review and approval of drainage/stormwater plans by the town engineer before construction starts. Commissioners noted an appeals period of 10 days.

Why it matters: Residents near the lower Iron Springs corridor told commissioners the steep descent and narrow pavement have produced collisions and near‑misses; supporters said routing downhill riders off the paved road will reduce those conflicts. Commissioners and staff also flagged environmental and safety requirements — county CEQA review, design and grading permits, and state permits for stream‑bed and water‑quality work — that must be obtained before the project can proceed.

Staff described the requested use as a revocable encroachment permit because the work affects an unimproved portion of the Iron Springs Road easement. Michael Dybeck, executive director of Marin Council Scouting America, said the exit provides an off‑road downhill route “to cut off downhill traffic for mountain bikers exiting the camp,” not to increase usage. Environmental planner Paul Kurfman, who has worked on the project’s technical permitting, told the commission the developer is seeking multiple approvals and that the construction window is limited: materials must be ordered in time for a proposed August 15–October 15 work season. Kurfman also told the commission that the county document is a negative declaration rather than a mitigated negative declaration.

Public commenters were sharply divided. Several neighbors said the trail would not prevent collisions that occur farther down Lower Iron Springs Road and raised concerns about hillside stability, erosion and the proximity of private backyards to the exit. One resident summarized recent incidents he said occurred on the lower road and urged caution. Mountain‑bike teams, youth riders and trail‑building groups urged approval, saying the exit would remove a large portion of downhill traffic from the road and that volunteers and professional trail builders would design and maintain a sustainable alignment. Access for Bikes and the Marin Council said they have retained geotechnical and trail‑building experts and offered to meet with concerned neighbors to review design and construction details.

Commissioners discussed sight lines, whether the gate and bollards will slow riders sufficiently, the presence of Northern spotted owl nest records in the area, and the need for county approvals for grading, the CEQA decision and nautical/state permits. Commissioner suggestions that the town engineer review the submitted drainage and grading details were incorporated into the approval as a condition. Commissioners also noted the encroachment permit is revocable if future public needs change or if the permit does not perform as intended.

The resolution approved by the commission (Resolution 2025‑05) includes a condition requiring the applicants to provide to the town the specific stormwater/drainage plans for the public right‑of‑way for review and approval by the town engineer prior to construction, and to install trail‑crossing and quiet‑zone signage before the trail opens. The applicants were advised that county final action on the CEQA negative declaration remains pending and that additional state permits (Department of Fish and Wildlife stream‑bed alteration agreement; Regional Water Quality Control Board waste‑discharge requirements) and Corps of Engineers consultation remain on the project schedule.

What’s next: The applicants said they expect to complete permitting in time to order materials and build in the late‑summer construction window if county and state approvals are obtained. The town’s approval is subject to a 10‑day appeal period; the encroachment permit remains revocable by the town for future public uses or if the permit does not meet public‑safety expectations.