Short informative title: Quantitative assessment of acute impacts of suspended sediment on carp in the Yellow River

Abstract

AbstractSediment concentration usually increases during the reservoir sediment flushing or natural floods, which may result in acute hypoxia stress and death of fishes in river reaches. Deceased fishes often appeared during periods of the reservoir sediment flushing in the Yellow River. To assess the quantitative impacts of high sediment concentration on carp, the suspended sediment concentration‐exposure duration model (SEV model) was applied and revised. With data from field surveys conducted during the sediment flushing of the Xiaolangdi Reservoir, the sediment flushing in 2009 was assessed as having no lethal effect. However, for the flushing in 2010, the fish mortality rate was assessed to be less than 20%. By analysing the data from experiments that exposed carps to different sediment concentrations, the SEV model tended to underestimate the acute impact of high sediment concentration (>30,000 mg/l). The SEV model was revised by refitting with experimental data. The comparison between the models showed that the severity effect values (SEVs) calculated by the revised model were closer to actual observations. The revised model was validated with data from previous field surveys. This research could provide a scientific basis for river sediment management and eco‐friendly reservoir sediment flushing operations.