Current and future state of groundwater salinization of the northern Elbe-Weser region

Deus, Nico
Elbracht, Jörg
Azizur Rahman, M.
Wiederhold, Helga

DOI: https://doi.org/10.1007/s00767-021-00496-w
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11005
Deus, Nico; Landesamt für Bergbau, Energie und Geologie, Hannover, Germany
Elbracht, Jörg; Landesamt für Bergbau, Energie und Geologie, Hannover, Germany
Azizur Rahman, M.; formerly Leibniz Institut für Angewandte Geophysik, Hannover, Germany
Wiederhold, Helga; Leibniz Institut für Angewandte Geophysik, Hannover, Germany
Abstract
Salinization of the upper aquifer of the northern Elbe-Weser region almost extends to the surface. Chloride content exceeds 250 mg/l and the groundwater is therefore, according to the German Drinking Water Ordinance, not suitable as drinking water. The chloride content in the aquifer originates from early flooding with seawater which occurred during the Holocene sea level rise. Depth and extent of the salinization were mapped by airborne electromagnetic surveys and validated by groundwater analyses. In the transition zone between the marshlands and geest areas, the fresh-saline groundwater interface falls to a depth of > −175 m NHN. Due to the extensive drainage of the marshlands, seepage of fresh groundwater is impeded. Instead, an upconing of the fresh-saline groundwater interface appears due to an upwardly directed hydraulic gradient. Due to climate change, chloride concentrations will increase along the coastlines. Further inland, a decrease of chloride content in near-surface groundwater will occur.
Subjects
Fresh-saline groundwater interfaceHEM
Drainage
Cl/Br ratio
Climate change
Süß‑/Salzwassergrenze
HEM
Cl/Br-Verhältnis
Klimawandel