A sensitivity study for the Amstel River Basin water quality model

A sensitivity analysis with the FAST method (Fourier Amplitude Sensitivity Test) was carried out with an application of the Sobek model code to the Amstel River Basin. The sensitivity analysis was used to study the contribution of six model parameters to the number of days the chloride concentration exceeds the water quality standards and the summer averaged total-phosphorus concentration at one location in the river network. The aim of this study was to test whether a sensitivity analysis (SA) with the FAST method is feasible for complex water quality model applications, such as networks of rivers and channels and eutrophication models. Even if a lot of a priori knowledge about the water system is needed for the selection of relevant input parameters and representative output parameters and locations, the use of SA methodologies appears to be a very useful tool in benchmarking river basin models.