Project members: David Burs, Thomas R. Rüde

In this project, water flow and permeability distribution in a tectonically complex karst aquifer on a regional scale are studied and simulated by means of high-performance computing.

The study area Hastenrather Graben, located about 15 km northeast of the city of Aachen, has a complex tectonic history. Folded Devonian to Carboniferous bedrocks outcrop on the graben’s shoulders are overlain within the graben by unconsolidated Tertiary and Quaternary sediments. The main limestone aquifer is used by the local water utility energie & wasser vor ort GmbH (enwor) which kindly supplies preliminary hydraulic and geological data.

The complex geological structure and possible hydraulic connections between nappes are addressed by detailed geological mapping using percussion penetration drillings and hydraulic investigations like pumping tests. Further geophysical investigations are conducted in cooperation with the Institute for Applied Geophysics and Geothermal Energy (GGE, RTWH Aachen). Based on these data a detailed three-dimensional geological model of the study area is set up using spatial interpolation and implicit geometric modeling. Another goal is to set up a detailed hydrogeological conceptual model, which can be used as input for numerical simulations.

In cooperation with the GGE numerical simulations are conducted using high-performance computing for analyzing experimental data, in particular piezometer time series and pumping test data, at the Centre for High-Performance Scientific Computing in Terrestrial Systems (HPSC TerrSys) of the Jülich Forschungszentrum. Hydraulic parameters and their uncertainties are estimated in an iterative process by simulations based on Monte-Carlo and Ensemble-Kalman-Filter approaches.