Sensitivity Analysis of Hydrologic,Hydraulic and Economic Uncertainties in Design of Flood Control Systems

Design of flood control systems are subjected to different kinds of uncertainties of hydrologic, hydraulic, geotechnical, and economic along, due to inherent behavior of flooding and random errors associated with measurement. The purpose of this paper is sensitivity analysis to determining the effect of uncertainties on the dimensions of design parameters.Therefore, using LINGO software a nonlinear optimization model based on risk analysis in both deterministic and probabilistic scheme have been developed for design of one of the most common structural flood control measure. In The probabilistic design, each of uncertainties once separately and once again all together are applied and Monte Carlo simulation for uncertainty analysis has been used. In this paper a reach in the Moali-abad river at north of Shiraz city, has been considered as case study. According to the results of probabilistic and deterministic models, the optimum return period equal to 20 years. Unlike the deterministic model that every output (design parameters) is single valued, stochastic model gives a range for each parameter that its value affected by the uncertainty imposed. The results show that applying the hydrologic uncertainty in the design is more efficient than economic uncertainty, and the economic one is more efficient than the hydraulic uncertainty. In the situation of limited time and budget, it has suggested that at least hydrologic uncertainty has been considered in design.