Lumped Conceptual Hydrological Modelling in Combination with GIS for Integrated Watershed Management

Hydrological models are often used to simulate surface water in a correct way to be a good basis for decisions regarding the development and management of water resources. The applicability for integrated watershed management of the lumped conceptual rainfall modelling system NAM (Danish Hydraulic Institute) has been tested. Meteorological data and stream flow measurements were used for six subcatchments in the Belgian River Dender basin (1384 km²). Calibration and validation of the models were performed on the basis of new concepts. Furthermore, different subcatchment characteristics (land use, soil characteristics and drainage conditions) are analysed by using GIS. Then subcatchment characteristics, discharge time series properties and model parameters are compared to allow an assumption to be made for model parameters for ungauged subcatchments. In addition, sensitivity of the results to rainfall data from measurement stations at different distances from the catchment and with different measuring accuracy was studied. Also the importance of corrections on the rainfall time series was analysed. Results indicate that corrected rainfall measurements give more accurate results than the original ones. Moreover, the closer the measurement station to the catchment, the higher the accuracy of the results.