Comparative Study of Flood Coincidence Risk Estimation Methods in the Mainstream and its Tributaries

Na Li,Shenglian Guo,Jun Wang,Feng Xiong,Yuzuo Xie

doi:10.1007/s11269-021-03050-8

Na Li, Shenglian Guo + Show 3 more

Open Access

https://doi.org/10.1007/s11269-021-03050-8

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Abstract

The coincidence of floods in the mainstream and its tributaries may lead to a large flooding in the downstream confluence area, and the flood coincidence risk analysis is very important for flood prevention and disaster reduction. In this study, the multiple regression model was used to establish the functional relationship among flood magnitudes in the mainstream and its tributaries. The mixed von Mises distribution and Pearson Type III distribution were selected to fit the probability distribution of the annual maximum flood occurrence dates and magnitudes, respectively. The joint distributions of the annual maximum flood occurrence dates and magnitudes were established using copula function, respectively. Fuhe River in the Poyang Lake region was selected as a study case. The joint probability, co-occurrence probability and conditional probability of flood magnitudes were quantitatively estimated and compared with the predicted flood coincidence risks. The results show that the selected marginal and joint distributions can fit observed flood dataset very well. The coincidence probabilities of flood occurrence dates in the upper mainstream and its tributaries mainly occur from May to early July. It is found that the conditional probability is the most consistent with the predicted flood coincidence risks in the mainstream and its tributaries, and is more reliable and rational in practice.

Highlights

Nowadays, flood problems have become more and more prominent, which account for a large part of allnatural hazards in the world (KvočKa et al 2016)
The coincidence of floods in the mainstream and its tributaries may lead to a large flooding in the downstream confluence area, and the flood coincidence risk analysis is very important for flood prevention and disaster reduction
It is found that the conditional probability is the most consistent with the predicted flood coincidence risks in the mainstream and its tributaries, and is more reliable and rational in practice

Summary

Introduction

Flood problems have become more and more prominent, which account for a large part of allnatural hazards in the world (KvočKa et al 2016). Large floods can be caused by the combination of floods in the mainstream and its tributaries (Prohaska and Ilic 2010). The flood peaks and volumes will superimpose into large floods, threating the safety of the downstream river (Chen et al 2012; Wang 2016). It is of great significance to study the flood coincidence laws in the mainstream and its tributaries, which can provide a theoretical basis for the formulation of flood control and dispatching plans in the basin, and offer a reference for the construction of flood control facilities in the downstream. The flood coincidence is a multivariable frequency combination event, which can be studied by the multivariable hydrological analysis method (Feng et al 2020). In flood frequency analysis (Tsakiris et al 2015; Zhong et al 2018; Moftakhari et al 2019; Karahacane et al 2020; Dodangeh et al 2020), rainfall frequency analysis (Ashkar and Aucoin 2011; Zhang and Singh 2012), drought frequency analysis (Montaseri et al 2018), and multivariate simulation (Chen et al 2016; Jane et al 2020)

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