Seminar paper from the year 2011 in the subject Geography / Earth Science - Physical Geography, Geomorphology, Environmental Studies, grade: A, Swedish University of Agricultural Sciences (Department of Aquatic Sciences and Assessment), language: English, abstract: This report investigates the relationship between the degree of imperviousness ¿ surface sealing ¿ and the water balance ¿ surface runoff, evapotranspiration and infiltration. It synthesizes case studies for the cities Leipzig, Dessau and Munich in Germany and the Grote-Nete catchment in Belgium and compares the effect of different urban land uses on the water balance. The annual precipitation ranges from 530 to 950 mm. Depending on the respective hydrological properties and land use characteristics a linear increase of surface runoff with increasing degree of imperviousness could be found for all of the German studies. Evapotranspiration and infiltration decline with an increasing degree of imperviousness. The relationship for both is not distinct as for surface runoff. The impact on the water balance does not significantly deviate for different levels of precipitation.