Scientists knew going into this year that water temperatures were going to negatively impact both the winter- and fall-run Chinook on the mainstem Sacramento. Without major infrastructure improvements at Shasta, this will not get any better when we have years of prolonged drought. Good news is that the early storms allowed fish into the upper Sacramento tributaries. Churn, Cow, Clear, Middle, Battle, and even little Salt Creek had tons of salmon in them. The smell on Clear Creek this fall was reminiscent of Alaska. I would not be surprised if more fish ended up in Clear Creek than the mainstem above Clear Creek.
Dropping the flows in the fall is the standard practice of Reclamation. Several agencies document the redd dewatering and stranding that occurs throughout the season. Relatively few (<5%) of redds are dewatered and it is generally too early to strand significant numbers of juveniles. To me this is just an issue of public perception, I do not think redd dewatering and stranding are major issues to the recovery of salmon.
I have major issues with their turbidity assessments. First off, 7 NTUs is nowhere near lethal (or sublethal) for any salmonids. If it was, salmon wouldn't exist (think visibility of glacial rivers in AK/BC that support salmon). Secondly, the relationship between turbidity and total suspended sediments (TSS) is not comparable. Turbidity measures light absorption while TSS measures physical sediments in the water column. These two measurements are inherently related but you can't just take a turbidity measurement and assume TSS levels. I was curious and went back to check some of the data I collected while in grad school. The relationship between turbidity and TSS in my samples was about 3 NTUs:1 mg/L TSS but varied from less than 1:1 to 7:1. Even chronic turbidity issues would need to be in the hundreds/thousands before you would expect lethal or sublethal effects according to the source they provided. Turbidity is going to be an issue for the next several years as all that ash and silt from the fires makes it down the system.
“There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.”
― Issac Asimov
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