Before and after the retaining wall installation along Alpine Road Trail

Midpen Finalizes Retaining Wall Construction Along Alpine Road Trail

Before and after the retaining wall installation along Alpine Road Trail (Zachary Alexander/Midpen)

Midpen is one step closer to reestablishing Alpine Road Trail as a safe regional connection between Portola Valley and Skyline Boulevard following completion of major repairs to the lower trailhead, where the paved road meets a dirt trail.

Over the past few years, several slipouts and small slides at the lower trailhead destabilized this segment of trail and contributed to sedimentation into Corte Madera Creek. Following a three-month construction closure in fall 2023, work has concluded on two retaining walls that will help prevent a total washout at the trailhead and preserve this portion of trail for visitor use and maintenance and emergency response vehicle access. Alpine Road Trail has since fully reopened to visitor access.

Since 2018, Midpen staff have been working on the design, permitting and construction of major repairs to the portion of Alpine Road that runs adjacent to and through Coal Creek Open Space Preserve. Construction of the retaining walls accomplishes one goal of the trail improvement project, which along with several significant culvert repairs and replacements, addressed erosion and trail stability concerns across the whole trail. The project will be fully completed in spring 2024 following finalization of a new, more sustainable bypass trail alignment to replace the existing, informal bypass trail.

These final repairs will allow for continued use of Alpine Road as a safe and sustainable regional trail connection for cyclists, equestrians and hikers alike while decreasing impacts on Corte Madera Creek and protecting wildlife that depend on the watershed for habitat.

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