Modulation of sediment load recovery downstream of Three Gorges Dam in the Yangtze River

Abstract The sediment load in the Yangtze River downstream of Three Gorges Dam (TGD) has substantially declined recent decades. decrease is more profound below TGD, e.g., a 97% at Yichang, compared with that delta apex, 1200 km downstream, 75% decrease, implying along-river recovery. Two large river-connected lakes, i.e., Dongting and Poyang Lakes, may play role re-establishment river’s morphodynamic equilibrium, but quantitative data-based understanding this interaction not yet available. In work, we collected series field data to quantify gain loss river-lake system middle-lower River, evaluate lake’s response reduction riverine supply. We find Lake shifted from net sedimentation erosion 2006 2000, back regime again after 2017 2018, respectively. Natural adaptation sand mining an important changes whereas dominates abrupt Lake. contributed maximum by 38% (2015) 17% (2006) (respectively) recovery regime, riverbed main source. These relative contribution sources also indicates time ~ 20 years lakes towards new equilibrium state. It noteworthy lakes’ buffer effects be overestimated as supplied rather small significant dam trapping upstream basin source degradation. results imply river management restoration should take into account interactions feedback impact decadal scales.