Author(s): Maria Manuela Portela; A. Betamio De Almeida; Ana Isabel Oliveira
Linked Author(s): A.P. Betamio de Almeida
Keywords: Free surface profile; Uncertainty analysis; Flood conditions; Manning coefficient; Ground elevation
Abstract: The paper exemplifies how the uncertainty in a free surface model under flood conditions in a reach of a natural river reach can be addressed. Among the different variables that represent sources of uncertainty in such model only the peak discharge, the roughness coefficient and the river channel elevations were analyzed. Based on those variables, different uncertainty scenarios were studied, according to the variable that was considered embedded of uncertainty. To ascertain the uncertainty of each variable, a probability distribution function was assigned to it and a large number of synthetic values of the same was generated based on the Monte Carlo random sampling technique. Introducing those values in the hydraulic model as many water surface profiles along the river reach as the number of synthetic values of the variable were obtained. The uncertainty that outcomes from those water profiles was characterized by the empirical distribution of the flow depths in each cross sections of the river reach. The results achieved are presented and discussed aiming at contributing to establish hydraulic design criteria informed by uncertainty.
Year: 2014