Planning commission approves second driveway and tall retaining walls at 800 Corte Madera Avenue with conditions

The Corte Madera Planning Commission on Tuesday approved a design review and a variance to permit a second driveway and retaining walls taller than three feet at 800 Corte Madera Avenue, voting 4–1 after more than two hours of testimony from neighbors, staff and the applicant.

Planning staff and the applicant said the proposal would add a driveway from Alta Terrace to an existing rear service road, increase lot coverage from about 3.5% to roughly 4%, remove 47 trees (22 of them meeting the town’s permit‑size threshold), and construct retaining walls ranging from about 6 inches to 12 feet 5 inches. The commission approved the project subject to revised conditions including limits on construction hours, additional requirements for drainage and monitoring, aesthetic treatments for visible walls, and neighborhood outreach before building permits are issued.

The project matters, neighbors and commissioners said, because it alters town right of way used today as an informal open space entrance and requires removal of dozens of trees on an 11.5‑acre, steeply sloped property that borders the Alta Bowl Open Space Preserve. Opponents warned of erosion, increased vehicle activity on narrow Alta Terrace and Sausalito Street, and permanent change to a public path; proponents and the Central Marin Fire Department said the secondary driveway would improve emergency access and evacuation options.

Staff presentation and project details Martha (planning staff) told the commission the application includes design review PL24‑0048 and variance PL25‑0016 to allow a new northern‑side driveway, drainage and grading, an entry gate, and retaining walls that exceed three feet within the rear setback. The property is in the R‑1‑C zoning district, the Hillside Land Capacity District and the wildland‑urban interface. Planning staff said the driveway would use a portion of unimproved town right of way and that a license or encroachment agreement would be required for improvements in that right of way.

According to staff, the driveway would raise lot coverage from about 3.5% to 4%; require removal of 47 trees (30 of them bay laurels, which the town tree ordinance identifies as…