Well field analysis (Contact: Dan Rosbjerg / Peter Bauer-Gottwein)
The design and management of well fields have significant impact on the quantity and quality of abstracted groundwater. Inappropriate borehole design can resulted in unanticipated geochemical processes that can degrade water quality. Poor management of the abstraction strategy can also cause quality problems. Analysis of these problems requires an understanding of both hydraulic and geochemical mechanisms. Appropriate definition of well protection zones is also an active area of research.
Groundwater-surface water interaction (Contact: Philip Binning / Flemming Larsen / Dan Rosbjerg / Peter Bauer-Gottwein)
Surface-water and groundwater systems are dynamically coupled, with surface water often controlling the local recharge rate in aquifer systems. Each reservoir has its own characteristics including those that govern the volume of water available, the quality of the water and the cost to supply water from the source. Careful management of the sources is required to meet often unforeseen constraints such as drought and contamination events. Current projects include the interaction between surface-water and groundwater in a near surface fluvial sandy deposits in the Red River plain in Vietnam, where this process is affecting the spatially distribution of arsenic in the aquifers, and the development of models for conjunctive groundwater and surface water management in urban environments.
The natural flushing and up-coning of saltwater in limestone aquifers(Contact: Flemming Larsen)
Due to quality problems in near surface reservoirs attention is now being directed towards the potential for groundwater abstraction from deep limestone aquifers. However, upward movement of saline water of marine origin from the deeper groundwater underlying the limestone aquifers may be a threat to the quality of groundwater. The mechanisms controlling the stability of the interface between salt and fresh water are analyzed using results from geophysical investigations, chemical data from abstracted water and numerical groundwater models where the effects of density dependent flow are accounted for.
Advective transport of oxygen in the unsaturated zone (Contact: Flemming Larsen / Philip Binning)
Transport of gaseous oxygen in the unsaturated zone has previously been thought to be controlled by diffusion from the atmosphere. However, in some cases, a much more efficient transport of gas takes place by advective transport due to atmospheric pressure variations through near surface, high permeable zones are through boreholes.
Studies are undertaken to quantify these process in the unsaturated zone in sandy deposits.