FLOOD FREQUENCY ESTIMATION UNCERTAINTY IN DESIGN PRACTICE: CASE STUDY OF SREMSKA MITROVICA, SAVA RIVER

Abstract

Flood frequency estimation is one of the most important tasks for hydraulic engineers. Design of hydraulic structures and systems require reliable estimates of high waters, which is not always easy to deliver. In this paper, uncertainty of flood frequency estimation common in practical use is presented in the case study of the Sava River at the Sremska Mitrovica hydrological station. Time series of 42 years daily flow records are statistically analysed on two samples, comprising annual maxima (AM), and peaks over threshold (POT). For uncertainty assessment, samples are analysed for several different scenarios, i.e. varying AM sample length as well as threshold flow for POT. Results indicate large uncertainty of flood frequency estimates, especially in the domen of low probabilities, as well as problem of adopting final value for practical use that will provide safety and optimum cost of the structures.