Variations in fluvial discharge of rivers over the last millennium along the eastern coast of the Liaodong Peninsula, China

Sediments delivered by global rivers are of utmost importance to the morphological formation and ecosystem evolution of estuary-coast-shelf systems. In this study, numerical modeling, supported by hydrological data, was applied to quantify the impact of climate change and human activities on the water and sediments delivery of five rivers along the east coast of the Liaodong Peninsula to the North Yellow Sea. Simulation results indicate that the water discharge and sediment load of these five rivers during the past millennium reached 27.88 +/- 5.97 km(3) y(-1) and 5.97 +/- 3.26 Mty(-1), respectively. Climate change was the most significant driving factor altering water discharge in the study area, with human activity producing an insignificant effect. Different from runoff, variations in sediment loads are dominated by human activities in past millennium. Our results demonstrate that the soil erosion of five rivers induced by human activities increased sharply by up to 8.1 times over the past few centuries, and that the total dam trapping efficiency for the eastern Liaodong Peninsula was 71.7%. If no dams had been constructed in the study area between 1941 and 2012, the total sediment load of the five rivers would have reached 11.33 +/- 5.70 Mty(-1). This reflects an increase of 92.6% relative to the period between 1000 and 1850 (5.88 +/- 2.93 Mty(-1)) and would have been 3.5 times the actual sediment load during the period 1941-2012 (3.21 +/- 4.61 Mty(-1)).