Land Subsidence in the Lower Rhine Embayment of Western Germany: A multi-decadal investigation from geodesy, geology, hydrology and finite element modeling

This contribution presents a comprehensive summary of the lessons learned from our studies on differential settlement and fault activation processes in the Lower Rhine Embayment of Western Germany. This region has hosted numerous mining operations and associated ground-water level adjustments for several decades. The remnants of several large, previously active open-pit mines are still visible today, as the land subsidence caused by mining-induced groundwater lowering continues to affect the landscape long after mining activities have ceased.

To understand the extent and progression of these effects, we  analyzed available leveling data collected since 1967, in conjunction with existing remote sensing observations from the European Ground Motion Service (EGMS). This extensive dataset allows us to reconstruct a comprehensive history of ground deformation in the region. We then integrate these findings with other in-situ geotechnical and geological measurements to develop a 2.5D geomechanical model and simulate the impact of large-scale groundwater pumping on contemporary continuous (i.e., land subsidence) and discontinuous (i.e., earth fissuring) surface deformation. The poro-elastic contact mechanics model is based on the lithological map of a cross-section passing near the Bergheim, Hambach, and Inden open-pit mines. The model is constrained by lithological, hydrological, geodetic, and field observations.

Additionally, we present the results of our extensive field surveys conducted in affected areas, which document the consequences of subsidence-induced fault reactivation and differential settlement. These geotechnical phenomena have led to moderate to severe damage to buildings, structures, and underground infrastructure throughout the region. Our findings highlight the long-term challenges posed by mining-related subsidence, emphasizing the decade-long environmental impact of mining and the need for careful consideration of these effects in future land-use planning and mining operations.