Research on annual maximum daily runoff of Zishui River Basin Based on GAMLSS model

Abstract

[Objective] Due to the influence of global climate change and human activities, extreme meteorological and hydrological events in the Zishui Basin are increasing day by day, resulting in the destruction of the consistency of hydrological processes, which makes the calculation result obtained by traditional hydrological frequency calculation method uncertain. [Methods] Therefore, based on hydrological data and meteorological data of Taojiang Station in the Zishui Basin from 1963 to 2022, a non-consistent model with different distribution of multiple covariates was constructed using the GAMLSS model. The good degree of fit of each model was comprehensively compared, and the design value of annual maximum daily runoff under different design frequencies was calculated using the optimal model. [Results] It is shown by the result that the contribution rate of precipitation to runoff change is 66. 52%, which is identified as the main reason for the increase of annual maximum daily runoff series in the Zishui basin. In addition, the best fitting effect is shown by the GA distribution model with precipitation,temperature, and reservoir index as covariables, which can be used to effectively describe the dynamic change characteristics of the annual maximum daily runoff in the Zishui basin under the influence of changes in precipitation and human activities. [Conclusion] As the annual maximum daily runoff of the urban development watershed is significantly affected by precipitation,the flood threat is being increased, and some reference for water resources management and water security maintenance in the watershed under the changing environment can be provided by the research result.

Keywords

GAMLSS model / covariate / annual maximum daily runoff / climate change / human activity / precipitation / hydrological processes / extreme rainfall