Water scarcity and pollution, its heterogeneous spatial distribution, and the protection against hydrological extremes are issues of global relevance. The water cycle is in progress of massive alteration in many regions of the Earth due to human action. Climate change has a direct impact on the water cycle. Therefore, a robust description of the water cycle and its spatio-temporal variations is mandatory. Nowadays, a multitude of hydrological models is in use for quantifying and balancing the components of the water cycle. Usually these models are calibrated and validated by comparisons with observed river discharge data. This information, however, is not sufficient to adequately understand and simulate the spatial distribution of water fluxes, water storage, and residence times in a holistic way.
Our research objective is to give an improved description of the water cycle and of its spatio-temporal variations. The focus of our approach is on the integration of data derived from a variety of measurement and monitoring devices into hydrological models on various scales in time and space (from local to global; from hourly to decadal). The direct quantification of water cycle components within river basins (internal state variables) is a primary aim. If successful, this will allow for using other variables in addition to discharge for calibrating and validating hydrological models (multi-objective calibration / validation). In this context we make us of the broad expertise at GFZ Potsdam in terms of environmental measurement and analysis techniques (geophysics, gravimetry, remote sensing, geochemistry).
Hydrological extremes, i.e. floods and droughts are globally important natural hazards. For instance, the most expensive natural disaster in Germany was the flood in August 2002, with a loss of about 12 billion euros. Due to climate change an increase of the risk due to hydrological extremes is expected.
Objective of our work is the development of methods for the quantification of risk as well as for risk management of hydrological extremes. We analyse the whole process chain from the meteorological cause via the runoff formation in the catchments, the flood routing in the rivers, the effect of flood protection, to the negative consequences of hydrological extremes. Therefore, simulation models for the different processes are developed and coupled. Besides these modelling approaches, data-driven approaches are developed to quantify frequencies and intensities of hydrological extremes and their consequences for man and environment.