The Klamath River, currently experiencing the largest dam removal project in U.S. history, is facing significant sediment releases that have coated portions of the riverbed with several inches to feet of fine silt and clay. A comprehensive research review published in Reviews in Fisheries Science provides critical insights into how these sediment levels may impact salmon reproduction.
The meta-analysis by Jensen et al. reveals that salmon egg survival drops precipitously when fine sediments smaller than 0.85 millimeters exceed just 10% of spawning gravel composition. With current sediment deposits on the Klamath far exceeding these studied thresholds, the findings raise important questions about salmon reproduction in affected areas.
The research quantifies specific impacts: for each 1% increase in fine sediments, the odds of survival decrease by 16.9% for Chinook salmon and 18.3% for coho salmon – both key species in the Klamath River system. The study found that coho salmon, an important Klamath species, showed the steepest decline in survival per unit of sediment increase among all species studied.
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This is a nightmare. And all those responsible are already moving on to other river dams. The Klamath River was an ‘experiment’ and they’ve been shouting “success” far and wide. All lies.