Reasons for the homogenization of the seasonal discharges in the Yangtze River

Yuanfang Chai,Haibin Xiong,Sixuan Li,Xia Yan,Jinqiu Ren,Yunping Yang,Xin Cui,Yao Yue,Boyuan Zhu,Yitian Li

doi:10.2166/nh.2020.143

Abstract

Abstract Allocations of water discharges between dry and flood seasons along the Yangtze River have significantly homogenized during the past decades, mainly due to precipitation change, regulation of key hydraulic works on the mainstream like the Three Gorges Reservoir (TGR), and the construction of numerous dams scattered in sub-basins. To reveal the specific roles of these three major factors in changing the seasonal discharges of the whole Yangtze River, this paper analyzes daily discharges during 1961–2014 at 16 hydrological stations from the far upper reach (the Jinshajiang Reach) to the estuary. We found that precipitation has only homogenized in areas 427 km downstream of the TGR, contributing 9.5–23.6% to the homogenized discharges. Even though the TGR is the largest hydraulic works in the world, it only contributes 17.5–27.2% to the downstream homogenization of seasonal discharge. By comparison, dams in sub-regions are a major contributor (61.1–100%) in the homogenized reach either upper or lower to the TGR. Of all the sub-basins, dams in Hanjiang River basin have the most significant effect (16.9%) on changing the allocations of seasonal discharges to the sea, followed by Wujiang (11.5%), Jialingjiang (10.1%), Yalongjiang (9.4%), Qingjiang (8.4%), and Daduhe-Minjiang (4.7%) river basins.

Highlights

IntroductionWater Disaster Prevention of Human Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, China
Yuanfang Chai Yao Yue Sixuan Li Jinqiu Ren Haibin Xiong Xin Cui Yitian Li State Key Laboratory of Water Resources and Boyuan Zhu Key Laboratory of Water-Sediment Sciences andWater Disaster Prevention of Human Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaYunping Yang Key Laboratory of Engineering Sediment, TianjinResearch Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, ChinaXia Yan River Department, Yangtze River Scientific Research Institute, Wuhan 430010, ChinaSeasonal hydrological processes in rivers all around the world have significantly changed under the impacts of rapid climate change and intensified human activities during recent decades (Miao et al )
Homogenization effect has occurred along the whole Yangtze River except the Jinshajiang Reach upstream of Panzhihua Station

Summary

Introduction

Water Disaster Prevention of Human Province, School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, China. Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China. Seasonal hydrological processes in rivers all around the world have significantly changed under the impacts of rapid climate change and intensified human activities during recent decades (Miao et al ). Variations in precipitation affect seasonal discharges in a faster and more violent way, often leading to flood and drought disasters which can cause huge economic loss and heavy casualties. The impacts of human activities on seasonal water discharges are widespread. By storing water discharges in flood seasons and releasing in dry seasons, dams effectively regulate the intra-year distribution of river flows.

Methods

Results

Conclusion