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Sacramento River Salmon Passage Projects

Several years ago I wrote a post on the loss of fish in the Sacramento River floodplain. Last year marked the completion of the Knights Landing Outfall Gates (KLOG) and Wallace Weir screening projects that will hopefully keep adult salmon from entering the Colusa Basin Drain. In the coming years, the Fremont Weir Passage Facility will allow adult salmon to escape the Yolo Bypass back to the Sacramento River. That is progress, but there is more to do.

We now need to focus on the Sutter Bypass and Butte Basin to the east of the Sacramento River. Like the Fremont Weir, the Colusa, Moulton, and Tisdale weirs need fixing. Adult salmon are blocked at these weirs. Young salmon pass over the weirs into the Butte Basin and Sutter Bypass and become stranded or die in the bypass. Like the Knights Landing Outfall Gates (KLOG), the Butte Slough Outfall Gates (BSOG) need fixing. In March, many adult spring-run salmon died (photo above) at the BSOG1 as Butte Basin floodwaters exiting the BSOG attracted salmon migrating up the Sacramento River. The salmon died in passing through the flap gate from direct physical damage or from low oxygen. Hopefully, the planned upgrade of the BSOG by the state will fix the problem.

Though much progress has happened on the Butte Creek/Slough and Sutter Bypass to correct fish passage problems,2 more needs to be done, especially in the Sutter Bypas3. Weir #1 hinders spring-run salmon passage to Butte Creek. CalTrout is planning a fix for that weir.