Physical geography of north-eastern Belgium - the Boom Clay outcrop and subcrop zone

The Boom Clay and Ypresian clays are considered in Belgium as potential host rocks for geological disposal of high-level and/or long-lived radioactive waste. A good description and understanding of the relationship between surface variables, as there are the geomorphology, hydrography, vegetation, soils, land-use and hydrology, is needed to evaluate the past evolution and assess the future evolution of the surface environment. Changing climatic conditions (glacials and interglacials), global sea-level variations and tectonic movements (uplift and subsidence) may cause the surface environment to change profoundly during the next 1 Ma. In this report we describe the characteristics of the surface environment of the Boom Clay outcrop and subcrop zone. Starting from the present status, the palaeogeographical and palaeohydrological evolution of the Campine area is described in the framework of the Quaternary geological history of the area. Finally, an overview of possible future conditions of the surface environment is given, based on the integration of the palaeorecord and available modeling studies.