Uncertainty Analysis of Estimated Flood by HEC-HMS Model in Jamishan Catchment

Flood estimation using rainfall–runoff model is associated with uncertainty due to the uncertainty of input variables (i.e. rainfall), parameters of model (i.e. loss) and structure of the model itself. Estimation of design flood considering the uncertainty of all stochastic variables is an important issue during the design of hydraulic structures. This study aims to analyze uncertainty of estimated flood by using rain pattern generator (RPG) and HEC-HMS models using Monte Carlo simulation. Furthermore, error propagation of the input variables and parameters of HEC-HMS model into the estimated flood hydrograph were evaluated. The results showed the uncertainty of rainfall duration; rainfall pattern and losses are expected to incur the most noticeable effects, on the uncertainty of flood hydrograph.