Frequency analysis of floods with joint functions, case study: Zayandehrood Dam

Subject Areas : Operation Management in Water Systems

Zahra Valaei Esfahani ¹ , Fatemeh Valaei Esfahani ² , Mehran Iranpour ³

1 - -MS of Aqiq non-profit institute, Shahinshahr, Iran.
2 - Senior Expert in Water Resources Management, Isfahan University of Technology, Isfahan, Iran
3 - Assistant Professor, Department of Civil Engineering, Lanjan Branch, Islamic Azad University, Isfahan, Iran.

Received: 2023-08-23 Accepted : 2023-10-13 Published : 2023-10-14

Keywords: Conditional probabilities, Bivariate frequency analysis, Copula functions, Bivariate return period, Zayandeh Rood Dam,

Abstract :

Analyzing the frequency of floods and knowing the probability of occurrence and return period of this phenomenon is important in how to exploit the reservoir. This phenomenon is inherently multivariate and the use of classical multivariate functions to analyze this phenomenon is limited. Therefore, it is recommended to use copula functions for multivariate flood frequency analysis. These functions combine the distribution function of the univariate distribution function by considering the type of correlation of the variables. For frequency of this phenomenon, the variables of peak discharge, volume and duration of flood are used. This study was conducted on statistical data of Zayandehrood dam. Based on goodness of fit criteria, the best function is fitted to the each of the variables. The correlation of each pair of variables is calculated and the copula function is selected based on the Akaike, NSE, and RMSE criteria. After that, the obtained univariate and combined return periods have been displayed. These results can be used to estimate the risk.

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