Global sensitivity analysis of parameters in DRAINMOD-S

In order to efficiently select the optimized parameters in DRAINMOD-S and figure out how the parametric variation influences the simulation results, sensitivity analysis of the parameters in the model was performed. Taking the pipe drainage desalting test as an example, which was conducted in Nantong Kowloon Reclamation Area, the Morris global qualitative sensitivity analysis was adopted to detect the the parameters sensitivity simulated in DRAINMOD-S of soil salinity in the profile against six parameters, namely, lateral saturated hydraulic conductivity Ksat, hydrodynamic dispersion coefficient D, maximum depth of surface water Sm, actual distance from surface to impermeable layer Im, drainage coefficient Dr and initial groundwater depth W. The results showed that Ksat has remarkable influence on simulation followed by D, Sm, Dr, while W and Im have little influence; nonlinear interactions among the parameters are different, and Ksat is the most significant. To guarantee the quality of the model simulation, accuracies of on-site measurement should be improved for the sensitive parameters and more emphases should be put on the sensitive parameters during the modelling. Meanwhile, the parameters which have strong nonlinear interaction should not be ignored. Therefore, model parameter calibration can be guided efficiently, and the applicability of the model will be improved. ©, 2015, China Water Power Press. All right reserved.