Pacific salmon need cold water and quality habitat to survive. As climate change continues to increase river temperatures, effective methods to restore cool-water refuges and logjam habitats need to be determined. Many salmon habitat restoration projects in the Pacific Northwest have built engineered logjams (ELJs) to create deep, cool pools and reconnect rivers to floodplains to replenish cool groundwater. However, the success of these projects is not often studied. This project will study restoration effectiveness in helping salmon adapt to climate change so that this once-abundant resource can continue to enrich the local culture, economy, and environment.
The Lummi Nation and Nooksack Tribe’s cultural and economic well-being are bound to the health of salmon stocks in the Nooksack River. Historically, the river was rich in natural logjams that captured wood and sediment and provided quality, cold water habitats for salmon. These logjams and their benefits were removed in the early 20th century and must now be restored to recover threatened salmon and degraded river systems. In partnership with the Nooksack Indian Tribe, Western Washington University and Natural Systems Design, this project will 1) assess the effectiveness of different types of ELJs in creating cool-water refuge for salmon and 2) assess the effectiveness of channel-spanning ELJs to increase floodplain connectivity and groundwater storage. This research will also inform strategies to improve water supply for both salmon and people during water shortages.
Recovery of the Nooksack early chinook salmon population is considered essential for the recovery of the threatened Puget Sound chinook population and Southern Resident Killer Whales. A longer-term goal of this work is to foster more effective salmon habitat restoration and support the recovery of salmon populations threatened by climate change and other factors affecting water temperatures.
