Geophysical mapping of the subsurface to support climate adaption in development areas

During the last decades there has been an increasing urbanization in many counties. It is estimated that in 2050 two-third of the world’s population lives in urban areas. The continuous growth of cities in combination with future climate changes present authorities with great challenges. Horsens municipality, Denmark are currently implementing climate change adaptation (CCA) plans for development areas. A key aspect of Horsens CCA plans is that development areas must handle surface water locally using various types of sustainable drainage systems (SUDS). However, at present time the knowledge about the geological and hydrological potential for the various SUDS solutions in the areas is limited.

Based on results from a 250 ha area we demonstrate how geological knowledge derived from geophysical mapping can support a sustainable and more efficient implementation of the CCA plans in development areas. The 250 ha is high-densely mapped with multi-configuration Ground Conductivity Meter (DualEM421) and supplemented with Airborne Electro Magnetic surveys, Electrical Resistivity Tomography (ERT) and boreholes. The depth of investigation for the DUALEM421 system is between 5 to 8 m and the horizontal and vertical resolution capacity of 1 m and ½ m, respectively. In connection with the geophysical mapping, infiltration tests are conducted on the various sediment types found in the development areas. The aim is to carry out field studies to a sufficient degree, making it possible to perform a quantitative correlation between the deposits’ electric resistivity and the infiltration capabilities. Based on the soil types’ different infiltration capabilities, it will be possible to produce a detailed infiltration potential map for the development areas. The project is conducted in collaboration with Horsens municipality and is part of the research project Coast to Coast Climate Challenge founded by the EU Life IP programme.