Spatiotemporal Variation of Annual Runoff and Sediment Load in the Pearl River during 1953–2017

Zhou Zhou,Chen Chen,Zhong Zhong,Wu Wu,Guo Guo,Wang Wang,Li Li

doi:10.3390/su11185007

Abstract

Anthropogenic activities have had a great impact on the characteristics of runoff and sediment load along the Pearl River in China in recent decades. We investigated the spatiotemporal variations, including the trends, abrupt changes, and periodicities of annual runoff and sediment load in the Pearl River by using the datasets from nine hydrological stations for the period of 1953–2017. We found that annual runoff was stable during the study period, with only two stations in the upper reach showing decreasing trends. Annual sediment load has generally experienced a significant decreasing trend, while one of the stations in the middle reach showed an opposite trend due to severe rocky desertification and soil erosion in the local karst terrain. Abrupt changes in sediment load were mainly between the 1990s and 2000s, when many hydraulic projects were conducted, implying the significant impact of anthropogenic activities on river sediment load. Results also indicate 2–4 year and 4–8 year periodicities in both annual runoff and sediment load, with long periodicities less significant than the short ones. Our study is conducive to water and soil resource management in the Pearl River basin, whilst provides a guide for other basins, particularly those characterized by karst terrains where local desertification and soil erosion might likewise cause increase in river sediment load.

Highlights

River runoff and sediment load play a critical role in the functioning of a river system that reveal the state of regional soil condition and water dynamics and eventually influence delta evolution [1,2]
It has been demonstrated that the sediment load has decreased by approximately 90% over the past 60 years in the Loess Plateau and, correspondingly, the Yellow River Delta suffers from erosion [13,16]
Variations in runoff and sediment load at nine gauging stations along the Pearl River during the period 1953–2017 were analyzed with the Mann–Kendall test and wavelet analysis

Summary

Introduction

River runoff and sediment load play a critical role in the functioning of a river system that reveal the state of regional soil condition and water dynamics and eventually influence delta evolution [1,2]. For China, the runoff and sediment load in the Yellow River have received considerable attention because of their drastic reductions since the 1950s Such reduction is mainly due to the implementation of numerous soil and water regulation infrastructures, the construction of large reservoirs, and climate change [13,14,15,16,17,18]. The difference between the two rivers is that dam construction is the primary reason for the sediment load decline in the Yangtze River, while water and soil conservation and reforestation projects contribute mostly to the reduction in the Yellow River [6,20]

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Discussion

Conclusion