Thermal groundwater use in urban areas - spatiotemporal scales and concepts

Over the last decades, the use of the urban subsurface and groundwater resources has increased significantly. Especially the use of groundwater for process and cooling purposes may result in considerable pressures on urban aquifers. Additionally, the extension of city infrastructures into the depth and the diffuse heat input of heated buildings have resulted in elevated groundwater temperatures in many urban areas. Therefore, for the sustainable development of urban subsurface resources, adequate management concepts are required. This includes the setup of tools that allow the investigation of the relevant spatiotemporal scales of processes that dominate groundwater flow and thermal regimes. An approach is presented, where data from high resolution depth-oriented temperature monitoring are incorporated into 3D numerical models that facilitate the simulation of groundwater flow and thermal regimes. The results form the basis for the development of concepts for the use of the urban subsurface for specific aquifer regions and future use scenarios.