Trinity River Restoration Project

Construction of Log Jam during restoration

Cardno worked with the U.S. Bureau of Reclamation to restore high quality salmonid rearing and spawning due to flow regulation and a lack of sediment and debris passing through the dam. We designed engineered log jams (ELJs) and provided a 2-D hydraulic model using River2D to help estimate the dynamics of placing wood structures to encourage a flow split into the side channel.

The downstream flow of the Trinity River was reduced to approximately 450 cubic feet per second, subsequently reducing high quality salmonid rearing and spawning habitat, which has drawn criticism from groups including the Yurok and Hoopa Valley tribes.

The model determined the design velocity and water surface elevations from the ELJ placement. Based on the analysis and modeling results, we prepared plans, specifications and cost estimates for construction of the ELJ.

Our work helped to address criticism of a dam on the California river that had reduced salmon habitat.