For some years now, the Hessian Agency for Nature Conservation, Environment and Geology (HLNUG) is focusing its 3D-modeling activities on urban areas, aiming to contribute to both integrated modeling and urban planning (e.g., Lehné et al. 2017, Lehné et al. 2013, Budde et al. 2017).

Experiences gained in the frame of the project “Darmstadt_3D”, which is delivering the urban subsurface including the technical infrastructure (sewage system, foundations, etc.), now are adopted for a working area in northern Hesse, southeast of Kassel. Geologically it is located in the Hessian depression and mainly characterized by WNW-ESE trending graben system of Kassel, and major features perpendicular to the main direction of the graben structure.

The just emerging 3D geological model is addressing the stratigraphic horizons Quaternary, Tertiary as well as the lower triassic formations Röt, Solling and Hardegsen and based on 449 quality checked drillings, of which several also have been used for the construction of 8 cross sections that help to better elaborate the fault network. In addition, geological maps and already existing cross sections are considered. First results show a complex tectonic situation with displacement rates that often exceed 100m. They also confirm the conceptual approach to be expedient and suitable for the intended extension of the working area to the area of Kassel. On the way the geological 3D-content will be parameterized for downstream applications such as modeling groundwater, and radon potentials as well as enriched by urban subsurface infrastructure in order to get a fully integrated urban 3D-information system.

In 2020, the Bundesgesellschaft für Endlagerung mbH (BGE) published the Sub-areas Interim Report, identifying areas with favorable geological conditions for a deep repository site for storage of high-level radioactive waste in Germany.

One key step was the identification of geological settings, where potential host rock formations (claystone, rock salt and crystalline rock) fulfil legally defined minimum requirements, e.g. depth (> 300 m), areal extension (varying between host rocks), and vertical thickness (> 100 m). Therefore, we examined 21 existing regional 3-D models generated by various German federal and state authorities with a different focus, detail and coverage (e.g. Rhine Graben, North German Basin). Hence, we had to deal with a large amount of data, different model scales, inhomogeneity and possible inconsistencies at the state boundaries.

In order to identify the potential host rock formations within the geological 3-D models and to ensure an equal processing, we generated a semi-automated workflow in SKUA-GOCAD^TM that extracted areas that fulfil the minimum requirements. However, the heterogeneous input data produced inconsistencies in the results of the workflow that required extensive quality control and correction. Another challenge was related to thickness calculations in the presence of fault surfaces. We quantified potential inaccuracies and showed that their impact is negligible with respect to the model scale.

Considering our approach, we provided a transparent and reproducible workflow within the search for a repository site for storage of high-level radioactive waste.

The Swiss Geological Survey (SGS) produces a suite of 3D geological models – both structural and parametric - in an established production environment, on a nation-wide basis. Output consists of regional-scale models of the deep subsurface (e.g. geological and temperature model of the Swiss Molasse Basin) as well as local-scale models of the shallow subsurface, with varying degrees of content and complexity. In addition, a new profile-based approach is currently being implemented – primarily using surface and shallow subsurface data - in order to expand the regional-scale model suite to cover the Jura region of Switzerland.

Modelling activities follow different approaches and workflows, depending on the types of available data and the planned uses of the various models. These data need to be in a geometrically, tectonically and stratigraphically harmonized state prior to modelling. This key requirement is made possible by the processes and standards that have been developed and implemented here at SGS e.g. legends, vector maps.

All of these models are stored and managed in the 3D database “GST” which is then used a source for directly publishing the 3D models to web- and app-based 3D-viewers or indirectly for other VR content. In the future, the SGS plans to enlarge the suite of models and streamline the production process.

Our presentation focuses on the latest developments as well as examples of the aforementioned regional- and local-scale models.

For decades the Ruhr Area in western Germany was dominated by extensive coal mining. Today, relicts of abandoned mines and the near-surface cavities are a hazard factor, for example at building sites. For an assessment of potential risks, the regional mining authority needs very detailed geological data. The calculation is based on the exact position of the coal seams at the Carboniferous surface and its loose rock covering.

To provide this, a very detailed 3D model of the shallow Paleozoic underground is build, reaching down to about 100 m. The Upper Carboniferous coal-bearing units were influenced by multiple phase tectonics and these complex structures were challenging to visualise and to model. Heterogeneous data of old mining sites, including plans of mine shafts as well as data of surface opening shafts, are combined with existing geological data and a high-resolution digital terrain model (cell size 1 m) in SKUA-GOCAD software. Challenging for the modelling process are the variable data types, scales and spatial accuracies. For example, plans of the mine shafts are partly older than 200 years and passed through numerous processing steps which had an impact on the positional accuracy. To harmonise the data, a manual constructed profile section network is used and a homogeneous data distribution is developed. The result is a 3D model of the shallow subsurface in the southern Ruhr Area with complex tectonic elements, combining geological and mining data. In accordance with the Geologiedatengesetz (GeolDG, 2020) all results will be stored and published in a GIS-database.