Using gravity-derived storage changes for hydrological model calibration (Contact: Peter Bauer-Gottwein)
Reliability of hydrological models is achieved and documented through calibration, i.e. the comparison of model results with field data. Traditional calibration data reflect hydrological conditions at the local scale, whereas in typical water resources management applications, we have to deal with much larger systems. A new generation of outdoor absolute and relative gravimeters is now available, which are accurate enough to monitor water storage changes in typical hydrological systems. Moreover, the Gravity Recovery and Climate Experiment (GRACE) has provided space-borne gravity measurements with unprecedented accuracy and global coverage.
Saline groundwater quality monitoring and modeling (Contact: Peter Bauer-Gottwein)
Salinization of soil, surface and subsurface water is a major environmental problem worldwide. Geophysical exploration methods provide powerful tools to map and monitor the freshwater-saltwater distribution in the subsurface. Groundwater salinity maps can help to identify recharge areas and viable groundwater resources and provide highly useful calibration data for regional-scale models. The Okavango Delta in Botswana serves as a case study area to assess the utility of various ground-based and airborne geophysical techniques for hydrological purposes.
Mapping and modeling of structurally complex hydrological systems (Contact: Peter Bauer-Gottwein)
Aquifer structure controls flow and transport processes in many groundwater systems, particularly in geologically highly heterogeneous media, for instance karst. For the purposes of regional water resources management, mapping aquifer structure becomes a key task. Various ground-based and airborne geophysical exploration techniques and remote sensing methods are available to improve the regional structural characterization of hydrological systems. The karst aquifer of Eastern Yucatan serves as a case study to assess the utility of different methods for aquifer structure mapping.
Hydrogeophysical data fusion (Contact: Peter Bauer-Gottwein)
Geophysics and remote sensing provide data that are indirectly related to the hydrological and hydrogeological parameters of interest (proxy data). For instance, electrical conductivity is a proxy for groundwater quality and formation porosity, land surface temperature is a proxy for actual evapotranspiration and the magnetic resonance signal is a proxy for subsurface water content. To exploit these new data sources to their full potential for hydrological applications a unified data assimilation / model calibration approach is required that can take in the various types of proxy data along with their uncertainty structures. This will ultimately lead to more reliable hydrological models and more robust predictions.