Wavelet Analysis of Dam Injection and Discharge in Three Gorges Dam and Reservoir with Precipitation and River Discharge

Lirong Yin,Lei Wang,Barry D Keim,Wenfeng Zheng,Kory Konsoer

doi:10.3390/w14040567

Lirong Yin, Lei Wang + Show 3 more

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https://doi.org/10.3390/w14040567

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Abstract

The Yangtze River has been the primary support of the resources and transportation of China. The Three Gorges Dam and Reservoir on the Yangtze River is one of the world’s largest dams. The influence caused by the dam and reservoir on the river system has been overwhelming and destructive. For better water resource use and flood-prevention planning, more understanding is needed regarding the dam’s impact on river discharge, regional precipitation, and frequency of extreme rainfall events. This study aims to analyze the changes in river discharge and regional precipitation records before and after the construction of the Three Gorges Dam. This research examines temporal correlations among these data by collecting daily dam injection and dam discharge records, the precipitation from ground stations, and river discharge. The time series are analyzed with the wavelet analysis. The precipitation datasets decrease in wavelet magnitude after 1998 when the dam was built in the wavelet analysis. The annual cycle, shown as a bright year line through the time range, still exists in the analysis result after 1998, but the magnitude of the annual cycle has reduced. The river discharge shows a decrease of wavelet magnitude at the three downstream locations. The possible explanation of this pattern could be the human-controlled dam discharge. The constant water level maintained in the reservoir by human control would slow down the flow speed and stabilize it.

Highlights

Determined by the Yangtze River Basin’s structure and functions, water resources, aquatic ecology, water environment, and flooding disasters reflect the interactions among the environmental changes [1]
This study aims to analyze the changes in river discharge and regional precipitation records before and after the construction of the Three Gorges Dam
Three datasets related to the Three Gorges Dam and Reservoir were

Summary

Introduction

Determined by the Yangtze River Basin’s structure and functions, water resources, aquatic ecology, water environment, and flooding disasters reflect the interactions among the environmental changes [1]. The Yangtze River Basin sits in the subtropical monsoon region. It originates from the high mountain plateau terrain in Southwest China and connects the East China Sea on the east coast, where the terrain is low and flat. The climatic and topographical conditions in the Yangtze River basin vary greatly. The river’s upper reaches are mainly glacial ice/snow meltwater, and the water volume is small and seasonal. In the lower reaches, flooding events caused by storms and heavy rainfall are the major threats related to the river. Storm surges and some tsunamis from the coast sometimes put excessive water into the interior land, causing coastal flooding [4,5]

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