Lake Tahoe California Lake Shore Bluff Stabilization and Restoration: Fid-Bau Portal

Lake Tahoe California Lake Shore Bluff Stabilization and Restoration

Chinchiolo, J.P.

Restoring the natural look of an area following a landslide or severe erosion repair can often rank just as high a project priority as the actual stabilization. This paper presents a non-traditional biotechnical stabilization and restoration approach using ballistic soil nails, galvanized steel mesh and native plant impregnated coconut fiber geocells in an area prone to rotational slope failures along the western shore of Lake Tahoe, California. Working within stringent Tahoe Regional Planning Agency (TRPA) guidelines, the project produced a restored shoreline face with a walking path through a newly stabilized high bank waterfront property. In addition to preventing further rotational failures, the approach mitigated widespread surface erosion and sloughing of the shoreline face. Traditional methods of mechanical slope stabilization such as benching, shotcreting, or anchoring would have been effective at stabilizing the shoreline movement and accommodating a new walking path. However, those approaches would have substantially altered the appearance of the shoreline and would have been unacceptable to TRPA and the property owners. In this case study, the benefits of biotechnical stabilization were crucial to the acceptance of the project. A combination of ballistic soil nails and custom vegetated mats both stabilized the existing rotational failure and provided anchorage points for the vegetated mats. That concept allowed cuts up to six vertical feet in the unstable sandy silt shoreline material. Working close to a protected lake and establishing plantings in the semi-arid Lake Tahoe environment presented real challenges, but a biotechnical stabilization system using mechanical elements and appropriate high mountain desert native vegetation met both the structural and aesthetic demands of the project.