The Impact Of Land Use Changes On The Hydrology Of The Grote Nete Basin BELGIUM Applying MIKE SHE

Abstract Analysis of the impact of land use changes on the hydrology is a key issue to set up a proper land-use planning project. In this study one distributed model MIKE SHE was applied to the hydrological system of the Grote Nete catchment a medium size catchment in Belgium. The existing Grote Nete MIKE SHE model was calibrated and validated using some additional parametersets sensitivity analysis which had not been tested and used in the initial model calibration to simulate the land use change impact on the hydrology of this catchment. The modelling results calibration 26 validation were verified by comparing with observed river discharges 4 discharge stations and groundwater heads 10 wells of 4 geological units. In MIKE SHE total 17 scenarios had been developed by changing the land use classes according to 4 hypothetical scenario categories and compared with the result of original reference calibrated model. The effect on discharges were analysed in terms of hydrological extremes peak flows and low flows that had been calculated applying Water Engineering Time Series PROcessing tool WETSPRO tool and the impact on groundwater conditions was expressed by the average monthly heads that were simulated by MIKE SHE. From the result of the hydraulic extremes it can be said that peak flows and low flows may increase or decrease with respect to the current reference scenario. The changes in groundwater heads simulated by the MIKE SHE model were insignificant. It was found that groundwater heads were negatively affected up to - 1m decline in summer and less affected 0.2 m decrease in wet periods for all geological units. The drier groundwater conditions might have severe agricultural and ecological implications as well as affect river low flows in all geological units. In this study the hypothetical land use scenarios had been developed to see the impact on the hydrology of the Grote Nete catchment although some scenarios did not give the expected results. So future research may be concentrated in refining the presented approach to reduce the effects of the main uncertainties identified in the present study.