Impact of climate change on freshwater resources in a heterogeneous coastal aquifer of Bremerhaven, Germany

A three-dimensional modeling study

authored by: Jie Yang, Thomas Graf, Thomas Ptak
Abstract: Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify river discharge of the river Weser flowing into the German Bight, which will alter both pressure and salinity distributions in the river Weser estuary. To study the long-term interaction between sea level rise, discharge variations, a storm surge and coastal aquifer flow dynamics, a 3D seawater intrusion model was designed using the fully coupled surface-subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density flow, variably saturated flow, irregular boundary conditions, irregular land surface and anthropogenic structures (e.g., dyke, drainage canals, water gates). The simulated steady-state groundwater flow of the year 2009 is calibrated using PEST. In addition, four climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1 m, (ii) the salinity of the seaside boundary increases by 4 PSU (Practical Salinity Units), (iii) the salinity of the seaside boundary decreases by 12 PSU, and (iv) a storm surge with partial dyke failure. Under scenarios (i) and (iv), the salinized area expands several kilometers further inland during several years. Natural remediation can take up to 20 years. However, sudden short-term salinity changes in the river Weser estuary do not influence the salinized area in the coastal aquifer. The obtained results are useful for coastal engineering practices and drinking water resource management.
Organisation(s): Institute of Fluid Mechanics and Environmental Physics in Civil Engineering
External Organisation(s): University of Göttingen
Type: Article
Journal: Journal of contaminant hydrology
Volume: 177-178
Pages: 107-121
No. of pages: 15
ISSN: 0169-7722
Publication date: 01.06.2015
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Environmental Chemistry, Water Science and Technology
Sustainable Development Goals: SDG 13 - Climate Action
Electronic version(s): https://doi.org/10.1016/j.jconhyd.2015.03.014 (Access: Closed)