Author(s): Mohammad Attari; Mostafa Taherian; Abdolmajid Mohammadian

Linked Author(s): Mostafa Taherian

Keywords: Manning’s roughness coefficient; Unsteady flow; Flood routing; Monte Carlo simulation; GLUE algorithm

Abstract: The analysis of steady and unsteady flows in natural rivers highly depends on the values of Manning’s roughness coefficient (n). Estimation of n values has higher uncertainty compared to the other effective parameters. In addition to the problems of determining the n in a cross section, its changes in the longitudinal section of rivers are also factors in increasing the uncertainty in flood routing. One of the methods for identifying the n values is the field measurement. In this study, a new method is presented to introduce the best filed measurement points in the longitudinal section of rivers. The proposed method is based on the use of Monte Carlo simulation, random search optimization, clustering, and GLUE algorithm. According to this method, the best field measurement points can be suggested in such a way that the degree of uncertainty is significantly reduced. The results of this study show that as the distance between the measurement points of Manning coefficient and hydrometric downstream stations increases, the error rate in flood routing decreases accordingly.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022955

Year: 2022