Connectivity in shallow, unconsolidated porous aquifers

• Applicants: Professor Dr. Frank Börner; Professor Dr. Peter Dietrich
• Subject Area: Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management ; Palaeontology ; Geophysics
• Term: from 2015 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 282295196

In comparison to the number of investigations dealing with the spatial variability of hydraulic conductivity fields in porous aquifers, less work is done so far to capture, measure and quantify connectivity of aquifer structures in both theory and especially in field experiments. This is especially true for heterogeneous aquifers. The unknown continuity of hydrostratigraphic units aswell as the uncertainty regarding their connectivity to each other led to problems in a realistic capture of solute transport. Hence, we feel that a further investigation of connectivity is of considerable relevance for the investigation of solute transport in heterogeneous aquifers. In this regard, our initial working hypothesis is that a similar relation between connectivity andsignal pulses of different frequencies exists for hydraulic tests and spectral induced polarization (SIP) signals. Hence, a relation between signal frequency and signal amplitude attenuation (also phase shift for SIP) should serve as an indicator (or measure) for connectivity. Within the project we will develop a theoretical concept(s) for connectivity, first. Furthermore, thepotential of geophysical (SIP) and hydraulic tests (e.g., Direct Push based cross-hole tests) as well as coupled geophysical-hydraulic tests will be investigated to evaluate the usefulness in the application of different signal frequencies for capturing connectivity. Therefore we will performsimultaneous laboratory and numerical experiments with varying connectivity setups. These experiments and simulations will be performed with increasing complexity, at different scales and varying experimental and measurement setups. The results will then be iteratively used to adjustand optimize our proposed theoretical concept(s). Finally, our main goal is to use our field/laboratory observation results to infer a measure for connectivity based on our developed (theoretical) connectivity concept.

• DFG Programme: Research Grants