Since dam construction in the early 1900s, Central Valley Chinook salmon have been cut off from their historical spawning and rearing habitat in the upper Feather River watershed. Spring-run Chinook salmon in particular historically utilized the upper river watersheds like the North Fork Feather River. In wake of population declines, especially of spring-run salmon, the California Department of Water Resources (DWR) is conducting a feasibility study. The question is how DWR can reintroduce salmon in high elevation watersheds. This Feather River project involves introducing fertilized salmon eggs into the North Fork Feather River upstream of Lake Almanor.
DWR is placing fertilized salmon eggs into the upper river rather than transporting adult salmon to spawn there. The ongoing study’s first goal is to determine the best method of introducing salmon eggs into an upstream system.
DWR scientists are analyzing two methods of salmon egg-placement. The first method, the “egg box method,” places eggs inside protective structures. The second method injects eggs straight into the river bed’s gravel in order to mimic natural settings. Monitoring determines which method is more successful.
The second goal of the study is to evaluate the suitability of habitat in the upper North Fork Feather River for salmon reintroduction.
Perhaps the most important action the study is accomplishing is evaluating how effectively DWR can capture juvenile salmon as they migrate downstream. DWR is aided in this part of the study by the presence of the Chester Diversion Dam, which is just upstream of Lake Almanor. Placement of traps to capture juvenile salmon at this existing infrastructure has allowed unusually high capture efficiency.
Why This Matters
Transporting salmon upstream of major Central Valley dams is not a new concept. It has been the subject of much controversy. The major criticisms voiced in the past 20 years are that transporting salmon upstream and downstream will not work and such measures are cost prohibitive. The feasibility study in the North Fork Feather River is a slow but steady approach that seeks to show how reintroduction can work and how to make it efficient. The study is relatively inexpensive and avoids the irrevocable expenditure of large sums of money.
Lessons learned in this study will help inform the feasibility and methodologies for potential long-term reintroduction programs in upper reaches of the Feather and Yuba rivers, and perhaps in other river systems in which dams currently block salmon from access to their historical habitat.