Big Oak Flat Tunnel No. 3

Client: National Park Service Yosemite Park
Location: Yosemite Park, CA
Cost:  $200,000
Completion Date:  2004


Designed a drainage system to divert water seeping from the north face of the tunnel and flooding the roads.


This tunnel spans the main access road into Yosemite Park and consists of 3 sections of concrete lining and 2 sections of shotcrete finish. Over the years, water has collected behind the concrete tunnel lining and seeped through the joints between the concrete lining and shotcrete This caused water to flow from the north face of the tunnel to the south face, causing hazardous driving conditions, especially during winter due to the formation of ice. AVA designed a drainage system to divert the water from the north face to a culvert running along the south face of the tunnel.