Impacts of climate change and human activities on the water discharge and sediment load of the Pearl River, southern China

Xing Wei,Peitong Ni,Shuqun Cai,Weikang Zhan

doi:10.1038/s41598-020-73939-8

Abstract

Global climate change and human activities have important effects on the water discharge and sediment load of the Pearl River. In this study, the water discharge and sediment load were investigated by using hydro-meteorological data from 1954 to 2018. The linear regression, Mann–Kendall abrupt test and double mass curve were employed to detect trends and abrupt change-points in water discharge and sediment load and to quantify the effects of climate change and human activities on water discharge and sediment load. The results revealed that the annual sediment load exhibited a significant decreasing trend at a rate of − 2.24 × 104 t/year, regardless of water discharge, and an abrupt change occurred in 1998. Human activities, especially dam construction contributed 96% to this change, while 4% was due to climate change. El Niño/Southern Oscillation (ENSO) events are often associated with low precipitation, resulting in low water discharge and sediment load, indicating that changes in ENSO periodicity could affect the inter-annual periodic variations of water discharge and sediment load. As population and economy boom, more dams are being built in the Pearl River basin, and special attention should be paid to the management and mitigation of the effects of dams on sediment load.

Highlights

Global climate change and human activities have important effects on the water discharge and sediment load of the Pearl River
Figure 4a1 reveals that Water discharge (WD) was consistent with precipitation during different decades and maintain synchronization, i.e., precipitation changes result in WD variability in the basin. These results suggest that precipitation is the main explanatory variable for WD in the Pearl River (PR)
During 1990s, precipitation increased by 8% relative to the baseline, resulting in increases in reconstructed WD and sediment load (SL) by 11% and 17%, respectively

Summary

Introduction

Global climate change and human activities have important effects on the water discharge and sediment load of the Pearl River. It has estimated that global runoff could increase by 4% based on an increase in global temperature of 1 °C9 Human activities, such as land use changes, freshwater extraction, and dam construction, have intensified over past several decades, often resulting in significant influences on river s ystems[4,6]. This study, aimed to (1) provide updated estimates of WD and SL from the PR into the sea, (2) give an in-depth explanation of the influences of ENSO events on WD and SL, and (3) give a quantitative evaluation of the contributions of climate change and human activities to changes in WD and SL at the basin scale. We believe this study will provide a better understanding of natural and anthropogenic contributions to major river water and sediment transport processes, which will provide scientific guidelines for global river management

Methods

Findings

Discussion

Conclusion