Upper Truckee River, Middle Reach Stream Habitat Restoration

Client: Public Works Department, City of South Lake Tahoe

Location: City of South Lake Tahoe

Summary: ENTRIX is providing engineering and restoration services to the City of South Lake Tahoe. The purpose is to improve fisheries, wildlife habitat and water quality to Lake Tahoe. The effects of airport development and land use practices reduced floodplain connectivity and modified flow conditions of the river. As a result, the ecological values and water quality characteristics have been impacted.

ENTRIX completed an alternatives evaluation and developed the preferred alternative, reviewed by a Technical Advisory Group and the Stormwater Quality Improvement Committee. ENTRIX completed final designs and construction documents, and is currently providing construction support services and post-construction monitoring. ENTRIX removed two concrete weir structures preventing fish passage. These barriers were replaced with riffles consisting of river run gravel and cobble. The riffles improved fish passage, habitat conditions and functions. A rock toe protection structure was constructed to prevent scour of a steep embankment. A second phase will include the construction of a 250 foot long engineered log revetment. This structure will stabilize an eroding bank, reduce fine sediment loads, improve water quality, and create vital fish habitat. Willow plantings create refugia that provide habitat benefits for macro-invertebrates and other aquatic species.

Key project features included hydrologic, hydraulic and sediment transport modeling and analysis, geomorphic and ecologic assessments; working closely with resource agencies and landowners; and providing public access, FEMA compliance and environmental permitting.