Title: Analysing the effect of land cover change on catchment discharge

The study was conducted to analyse the effect of land cover change on the catchment discharge and thereby to investigate the sensitivity of the hydrological model to those changes. The study area was Hjaltadalsá River which is located in the Hjaltadalur Valley in the north of Iceland. The WaSiM hydrological model was used to test the sensitivity of land cover change and GIS tools were applied to process the catchment delineation and manipulation. The analysis was performed under fictional formed five land covers such as grass land, wet land, barren land, heath land and forest land on the Hjaltadalur watershed. The simulated discharge under different land covers was tested with the observed discharge. The WaSiM model simulated the catchment discharge well. Generally, the simulated discharges for different land covers and observed discharges had similar trends with only small differences. However, the highest discharge was observed for barren land cover and the lowest for forest land cover for the summer and spring seasons. From the study it seems that simulated land cover change had little impact on the catchment discharge of the Hjaltadalsá River even though a slight difference was observed among the land covers. For further research in this field it would be worthwhile to simulate the joint effect of land cover and soil type change together.