Log Jams Provide Refuge 

Salmon Habitat Restoration in Thermally Impaired Waters: Engineered Log Jams, Hyporheic Exchange and Cool-Water Refuge

Engineered log jams are being tested for their ability to promote shallow groundwater upwelling, which can help create cool-water refuges critical for Pacific salmon.

Principal Investigator

James M. Helfield, Western Washington University, Department of Environmental Sciences


Engineered log jams (ELJ) are used to restore salmon habitat in streams by promoting development of deep pools, which help maintain the cool temperatures salmon require. Researchers will take advantage of the Nooksack Tribe’s plan to install ELJs on the Nooksack River, enabling them to make before-and-after comparisons of changes in streambed topography and temperature, upwelling from beneath the river bed stream bed and fish use. In addition, this research supports assessment through multi-year monitoring, which is lacking in many habitat restoration projects. And by providing research opportunities for college students, the project will promote building workforce capacity.