Estimating River Discharges in Ungauged Catchments Using the Slope–Area Method and Unmanned Aerial Vehicle

Shengtian Yang,Changsen Zhao,Juan Wang,Hezhen Lou,Pengfei Wang,Tongliang Gong

doi:10.3390/w11112361

Shengtian Yang, Changsen Zhao + Show 4 more

Open Access

https://doi.org/10.3390/w11112361

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Abstract

River discharge is of great significance in the development of water resources and ecological protection. There are several large ungauged catchments around the word still lacking sufficient hydrological data. Obtaining accurate hydrological information from these areas is an important scientific issue. New data and methods must be used to address this issue. In this study, a new method that couples unmanned aerial vehicle (UAV) data with the classical slope–area method is developed to calculate river discharges in typical ungauged catchments. UAV data is used to obtain topographic information of the river channels. In situ experiments are carried out to validate the river data. Based on slope–area method, namely the Manning–Strickler formula (M–S), Saint-Venant system of equivalence (which has two definitions, S-V-1 and S-V-2), and the Darcy–Weisbach equivalence (D–W) are used to estimate river discharge in ten sections of the Tibet Plateau and Dzungaria Basin. Results show that the overall qualification rate of the calculated discharge is 70% and the average Nash–Sutcliffe efficiency coefficient is 0.97, indicating strong practical application in the study area. When the discharge is less than 10 m3⁄s, D–W is the most appropriate method; M–S and S-V-1 are better than other methods when the discharge is between 10 m3⁄s and 50 m3⁄s. However, if the discharge is greater than 50 m3⁄s, S-V-2 provides the most accurate results. Furthermore, we found that hydraulic radius is an important parameter in the slope–area method. This study offers a quick and convenient solution to extract hydrological information in ungauged catchments.

Highlights

River discharge is a fundamental element of the hydrologic cycle and water balance [1,2,3]
Roads, and other river-crossing structures appear in the partial study area (SQ, Mu Ye (MY), Dan Yuti (DY), and Ka Latuowa (KL))
To resolve the problem of river discharge monitoring in ungauged catchments, this study combined four methods based on the classical slope–area method with unmanned aerial vehicle (UAV) remote sensing

Summary

Introduction

River discharge is a fundamental element of the hydrologic cycle and water balance [1,2,3]. It plays a leading role in the development of regional water resources and the protection of river ecologies [4,5]. There are large ungauged catchments around the world lacking hydrological data. As a typical ungauged catchment, arid and semi-arid zones account for 15% of the global land area, with. The harsh environment in these areas makes the establishment of traditional hydrological stations costly and difficult to manage, which is the primary reason for the lack of hydrological data.

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