Comparison of hydrogeological properties based on DCIP, surface NMR and hydraulic tests

The success and the costs of infrastructure projects depends to a large extent on a reliable characterisation of the subsurface. Information about the groundwater is crucial to protect groundwater resources and to avoid stability problems. Usually, drillings followed by hydraulic tests are conducted which are reliable but expensive and only give punctual information. The use of the geophysical methods Induced Polarisation (IP) and Nuclear Magnetic Resonance (NMR) can help to optimise drillings since they can give information about the hydraulic conductivity (K), the water content and the pore space characteristics. The combined methods were tested at three Swedish sites to investigate how reliably the hydrogeological properties of the underground can be characterised on a field scale. At the test site shown as example, it was accompanied by slug tests and the hydraulic profiling tool (HPT), where we could identify layers with different intrinsic permeabilities based on the IP data. Furthermore, we found that the water content is decreasing with depth. The comparison of the geophysical results with HPT and slug tests shows a correlation but more improvements regarding the K estimation from the IP data needs to be made.