Changjiang delivered more water and sediment into the sea than expected

Abstract:

Changjiang delivered more water and sediment into the sea than expected

Ya Ping Wang

State Key Laboratory of Estuarine and Coastal Research, School of Marine Sciences, East China Normal University, Shanghai 200241, China

School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210093, China

Corresponding author: Y.P. Wang, ypwang@nju.edu.cn

Abstract

Improved monitoring of material discharge from rivers would enable reliable assessments of the threat of environmental change to coastal habitats. Yet, the conventional method to estimate the river discharges is based on the record of the gauging station located closest to the river mouth, which could be hundreds of kilometres away, which is insufficient to produce accurate values. The study site was subject to tidal influences, so to obtain more accurate estimations of river water and sediment discharged to the ocean, over the course of one year in a global large river. Here we developed a method with the much higher frequent hourly measurement at the river mouth than the traditional hydrological daily measurement at the gauging station and validated the water discharge measured at mooring stations by cross-sections. The data show that when traditional estimation methods are applied (i.e., methods that use data collected at the most seaward gauging station), water and sediment discharge from the entire drainage basin to the East China Sea were underestimated by 4.4% and 20.3%, respectively. This study set up a delicate example to retrieve accurate water and sediment discharge measurement at the river mouth, making it possible to re-evaluate terrestrial material delivered into the sea, as well as improving the land boundary input and then prediction accuracy of ocean numerical model.