New approaches to the characterisation of aquitard properties and processes in alluvial groundwater systems

Scott Cook, PhD Candidate 

Supervisors: Wendy Timms, Bryce Kelly & Ross Brodie (Geoscience Australia)

Funder: Geoscience Australia and National Centre for Groundwater Research and Training

Abstract: Aquitards are rocks and sediment that retard the flow of groundwater. In contrast to aquifers which have high permeability and from which groundwater can be extracted in useful quantities, aquitards have low permeability and form natural barriers to groundwater flow. In alluvial groundwater systems, sand or gravel rich layers may form aquifers while silt or clay rich layers may form aquitards.

Understanding how aquitards influence groundwater flow processes is important for estimating leakage or recharge volumes to underlying aquifers. This research is important for understanding how extraction of groundwater may propagate to other aquifers or surface water.  This research will develop techniques to assess 3D connectivity through aquitards in alluvial groundwater systems via integration of hydraulic, hydrochemical, and geological information.

The field site is situated in an important inland basin where groundwater is extracted for irrigation of crops, town water supply and by coal mining. Concerns over the cumulative impact of multiple developments, including coal mines and coal seam gas development make the research relevant to numerous stakeholders.