Estimation of Long-Term River Discharge and Its Changes in Ungauged Watersheds in Pamir Plateau

Adilai Wufu,Yun Chen,Ligang Ma,Hezhen Lou,Chaojun Li,Shengtian Yang

doi:10.3390/rs13204043

Abstract

The Pamir Plateau is an extremely important water resource area for over 60 million people in Central Asia. With the increasingly significant response of water resources to climate change, timely hydrological predictions for the future supply are necessary. In the plateau, accessing and monitoring the glaciers and their melt outflow are challenging due to the harsh geographic environments. Unmanned aerial vehicles (UAVs) combined with remote sensing technologies offer great potential for providing information to improve water resources management and decision-making. In this study, we integrated UAV and satellite remote sensing data, and applied a water balance model to estimate monthly and annual river discharges for the ten river sections in the Eastern Pamir Plateau, China from 1999 to 2020. We found that the glacier area in the controlled basins of these sections has decreased by approximately 63% from 1999 to 2020. Basins with smaller glacier areas are more sensitive to climate change. The ten river sections are characterized by decreasing trends in monthly river discharge, with an average reduction of −21.05%. The annual variation of total runoff and glacial meltwater discharge is consistent with the monthly variation of discharge, and the average discharge from glacier meltwater accounts for 83% of the total runoff. We conclude that the overall decreasing trend of discharge is closely related to the recession of glaciers. Under the background of climate warming in the region, glaciers are no longer sufficient to support the increase in river discharge, which has passed its peak value and shows a decreasing trend.

Highlights

During the past decades, freshwater scarcity has become an increasing threat to the sustainability of human society [1]
The Pamir Plateau is located in the heart of Central Asia
Based on Unmanned aerial vehicles (UAVs) images and in-situ measured data, water surface width, roughness, and surface gradient were obtained, and river discharge was calculated by a hydraulic method

Summary

Introduction

Freshwater scarcity has become an increasing threat to the sustainability of human society [1]. In its most recent annual risk report, the World Economic Forum listed water crises as the largest global risk in terms of potential impacts [2]. Rivers are the most vital freshwater resources. In many regions of the world, they are the only water source supporting local socioeconomic development. The quantification and monitoring of river discharge are important to the sustainable management of this valuable resource and the prediction of its future conditions. Most rivers are fed by glaciers, which represent essential water reservoirs and contribute substantially to human society of the downstream oasis [3]

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Discussion

Conclusion