Title: Visualisation of flow and contaminant transport through karst aquifers
Researchers: De Lea Duran, Prof. Laurence Gill
Carboniferous limestone is the primary aquifer rock in Ireland, coinciding with the most productive agricultural land, areas of most economic activity and major centres of population. Much of this carboniferous limestone is karstified and as such, the aquifer is at greater risk of contamination and flooding issues due to the rapid transit of water, to the direct infiltration through swallow holes, the lowland nature of much Irish karst and the thin layer of soil cover which typically overlays them. It is thus of great importance to increase the often poor understanding of these complex systems. Karstic systems are highly heterogeneous geological formations which are characterised by multi-scale temporal and spatial hydrologic behaviour, which makes them particularly complex to study and model. Various different conceptual, analytical and numerical approaches have been used to model underground flows through karst aquifers across the world, from black box models to detailed numerical physically-based models. Once developed, such models can be used to simulate extreme weather events, longer term climate change patterns, floods event, contaminant plumes, etc. Lastly it is important to present those results as visually as possible as the stakeholders and the general public are often not familiar with karst and karst-related issues. The primary aim of this research project is to develop a state of the art modelling methodology in order to make the groundwater flow and contaminant transport through karst aquifers more understandable by means of visual 3D models. This will be applied to a number of Irish karstic catchments in order to shed light on their hydrologic behaviour.
The approach consists in numerical distributed modelling and relies on the following steps (i) application of a set of investigation and characterisation methods (ii) building of 3d geological models (iii) numerical flow modelling (iv) contaminant transport modelling and (v) transfer of results in animation software for visualisation. In order to do so, the project requires to coordinate and complement several ongoing iCRAG PhD studies in the groundwater spoke and synthesise findings into usable modelling platform. The PhD projects can contribute on two levels: (i) data collection on specific study sites and understanding of their functioning and (ii) conceptualisation and modelling of hydrological processes involved. They focus on different parts and processes of karst systems: diffuse infiltration, recharge, surface hydrology linked to ecosystems, contamination from septic tanks and fresh groundwater discharge into the sea.