Spatio-temporal variability in shallow groundwater and its effect on stream water quantity and quality
Although groundwater is often assumed to be stable over time and space, the variability of shallow groundwater chemistry can be large, and controls on it are poorly understood. This awhile streamflow in undisturbed catchments consists predominantly of groundwater, even during large events.
The chemical composition of groundwater at a certain location is related to the flow pathways, inflows from uphill and the surface, interactions with the soil, and mixing and variability in flushing frequency. Consequently, different parts of the catchment may have a different groundwater composition. However, in most catchment studies that use geochemical tracers to identify streamflow sources, groundwater samples are taken from only one or two wells, which are assumed to be representative for the whole catchment. Additionally, with the expansion of the connected subsurface contributing areas during events, different groundwater source areas contribute to runoff, which may have a different chemical composition than the sampled groundwater end-member.
The aim of this PhD project is to improve our understanding of the spatial and temporal variability in shallow groundwater chemistry in a small pre-alpine headwater catchment and its effect on streamwater quality. More knowledge of the spatial variability in shallow groundwater and its chemical composition can lead to a refined representation of the groundwater end-member in (time dependent) source-area analyses and thus more robust conclusions about the relative contributions of groundwater (or different parts of the groundwater) to streamflow.
Groundwater quality, isotopes, flushing frequency, pre-alpine catchments, runoff generation processes
Project Leadership and Contacts
Dr. Ilja van Meerveld (firstname.lastname@example.org)
Prof. Dr. Jan Seibert (email@example.com)
Duration of Project
From March 2016 to February 2019