El Portal Road

In early January 1997, several days of heavy, warm rains, combined with record flows in the Merced River, caused extensive flooding in Yosemite National Park. The river washed out the adjacent El Portal Road in 19 locations, disabling the main entrance to the park. In addition, the flood destroyed portions of the sanitary sewer serving the entire Yosemite Valley.

To expedite repairs to the 7-mile-long entrance road, the Federal Highway Administration awarded a $33.5 million design-build contract to Kiewit. This delivery method allowed crews to proceed at an accelerated pace, thus reducing interference to the environment and disruption to the park entrance.

To minimize environmental impacts on this historic roadway, a special mechanically stabilized earth retaining wall design used soil-nailing techniques. All walls received a shotcrete facing that is textured and stained to resemble stone rubble masonry. Work included major drainage improvements, rehabilitation and reconstruction of the damaged sanitary sewer, asphalt concrete pavement replacement, and guidewall design and construction.