Derivation and investigation of regional flood analysis models as a function of return period (Case study: Ardabil province)

Azartaj, Elnaz; Farzi, Parisa

Derivation and investigation of regional flood analysis models as a function of return period (Case study: Ardabil province)

Document Type : Complete scientific research article

Authors

Elnaz Azartaj ¹
Parisa Farzi ²

¹ M.S. student of Watershed Management, College of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran

² M.S. student of Watershed Management, College of Natural resources, Torbat Heidariye University, Iran

Abstract

Improving techniques of regional flood frequency estimation at ungauged sites is one of the foremost goals of contemporary hydrology. The evaluation of the frequency of flood events in ungauged catchments are usually approached by building suitable statistical relationships (models) between flood statistics and basins characteristics. In this study, regional flood frequency was curried out between flood as a dependent factor and physical characteristics as independent factors using inverse method in the catchments of Ardabil province. To yield a single model, return period was taken into account as independent factor. Study area consists 9 gauging stations in the central regions that seven gauging stations for calibration and 2 gauging stations for validation were used. Four types of models including Area, Area-slope, Area-slope-channels length models and Fuller model were studied. Results showed that lowest correlation between estimated parameters was concerned to Area model. Therefore estimated parameters of this model was unique and contact high confidence with compare to others models. Fuller model did not show suitable estimation of flood. Area, Area-slope, Area-slope-channels length models estimated flood with good accuracy for return period less than 50 years. Accuracy of mentioned models decreased with increasing return period. Area model with RMSE equal to 25.30 and 23.51 (m3/s) showed lowest accuracy and Area-slope-channels model with RMSE equal to 9.51 and 6.32(m3/s) highest accuracy for estimation of flood in the validation gauging stations.

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