Large-scale ERT survey for site characerization

Thesis details

Large-scale ERT survey for site characerization

• 6 months
• M.Sc.
• 90% Programming
• 80% Field work
• 10% Lab work
• 60% Theory
• 70% Processing
• 60% Interpretation
• 50% Geology

Contact person

©

M.Sc.

Nino Menzel

PhD researcher

nino.menzel@gim.rwth-aachen.de

+49 241 / 80 98273

The pollution and subsequent remediation of groundwater in potentially contaminated areas such as decommisioned military bases or airports has been of permanently increasing interest for environmental scientist during the last decades. It is of highest importance to have detailed knowledge about the lithological and hydrological setting in the polluted area before planning a remediation. Especially non-intrusive surveys that are sensitive to the parameters of interest, such as Electrical Resistivity Tomography (ERT) are well suited for the premlimnary site investigation since the subsurface is left undisturbed. Moreover, geoelectrical measurements provide a cost- and time-effective alternative to intrusive methods, like a raster of boreholes.

The decomissioned military air base in Sembach, Rhineland Palatine, was identified as suspect site for several hazardous pollutants and is thus of special interest for hydrogeologists. However, the regional geological and hydrological setting has not been defined in detail yet - past studies only roughly analyzed the regional setting, including stratigraphy and groundwater flow. Thus, several important characteristics, like the depth of the lower aquifer boundary or the exact flow direction of the groundwater, are yet to be evaluated. A large-scale ERT survey is planned to further forward the site characterization and ideally support the planning of the site remediation by adding more detailed information on both lithology and hydrology.

Your tasks:

• Conduct a feasability study for the planned field measurements based on lithological and hydrological data and suggest suitable locations for the geoelectrical 2D profiles.
• Perform the planned ERT measurements with the help of the other GIM members during a multi-day field campaign.
• Process and invert the datasets using pyGIMLi (Rücker et al., 2017) and evaluate the results. Ideally visualize the combined inverse models in 3D.
• Interpret the ERT models with regard to the available lithological and hydrological information.

Supplementary Documents

Rücker, C., Günther, T. & Wagner, F.M., 2017. pyGIMLi: An open-source library for modelling and inversion in geophysics. Computers and Geosciences, 109, 106-123.