River Basin Impact Assessment of Changing Land Use and Climate by Applying the ILWRM Approach in Africa and Asia

Methodological aspects of scale-related impact assessment from changing land use/land cover (LULC) management and climate on river basin water resources and their management are discussed. Both control the interactive hydrological process dynamics that transfer precipitation input on the landscape to the different surface and subsurface water resources components and ultimately to river runoff draining the river basin. As the integrated water resources management (IWRM) concept does not sufficiently account for the landscape-related process dynamics associated with LULC management, it is enhanced to the integrated land and water resources management (ILWRM) approach. The latter requires, firstly, a consistent methodological concept and, secondly, a toolset for its implementation. The DPSIR (D = Drivers, P = Pressures, S = State, I = Impacts, R = Responses) approach is a suitable analysis concept in this regard and is enhanced by a Decision Information Knowledge System (DIKS). Both are implemented by means of the integrated land management system (ILMS) toolset developed at the University of Jena, Germany, and tested in numerous research projects in Africa, Asia, Australia, Europe and South America. The majority of river catchment studies focus on a particular scale. Upscaling and downscaling of the hydrological knowledge they generate requires the separation of the generic knowledge components from their modifying local specifications. The interdisciplinary ILWRM applications presented in this paper from two projects in South Africa and SE Asia address this challenge by applying a multi-scale nested catchment approach (NCA) and respective upscaling and downscaling techniques to regionalize hydrological knowledge between scales.