Impact of karstic flow on Chalk aquifer function and water quality for security of water supply

We Invite applications for a fully-funded NERC CASE PhD studentship to work on an opportunity for investigating the impacts of contaminants on water quality and security. This research will exploit a unique and timely opportunity for forecasting the occurrence of contamination events affecting groundwater from one of the world’s most important aquifers. This project will entail an improved understanding of the impact of rapid karstic flow processes in chalk aquifers on water quality to allow preventive actions to be taken and facilitate improved future groundwater resource management.

BACKGROUND INFORMATION
The Cretaceous Chalk aquifer represents the most important groundwater resource in the UK and is also important ecologically for chalk stream ecosystems. Similar aquifers exist in France, Belgium, Netherlands, and Israel. The extent to which chalk aquifers show development of karstic features (widened fractures and conduit development due to dissolution by groundwater flow) is of interest because where karstic features connect sources of contaminants directly to borehole abstractions, water quality may be poor, especially during periods of high flow (extreme events). Where flow is more distributed because karst features less developed and smaller, water quality is consistently better.

IMPACT AND EXPECTED OUTCOMES
It is anticipated that this project will have a tangible impact on risk management strategies for groundwater contamination. The outputs of this research will be used for decision making by stakeholders in the UK such as the CASE partner company and Environment Agency but also more widely. By conducting fieldwork (e.g. geomorphological mapping of surface karst features, tracer tests between sinkholes and abstractions) and developing modelling approaches based on the results, the PhD student will provide a coherent explanation of karst development in chalk aquifers, and the impact of karst development on contaminant transport and therefore on the quality of abstracted groundwater. The outputs of this investigation will be transferrable to other karstic aquifer systems, and constitute the basis of a new generation of groundwater vulnerability mapping approaches.

OBJECTIVES
1. To identify key controls on development of karstic flow paths in soluble rocks such as the Chalk, e.g. the extent that karst development is stratigraphically constrained (i.e. controlled by geological layering).
2. To identify extent of Chalk karst development in areas where karst swallow holes are absent, as well as where these are evident at the surface (i.e. rapid karstic flow may still be occurring).
3. To develop better models for the development of karstic features in the Chalk aquifer, and for prediction of the vulnerability of groundwater to contamination for chalk and karstic aquifers generally.
4. To investigate how degree of karst development is affecting nitrate and pesticide concentration trends in Chalk groundwater abstractions, and their response to extreme weather events.

CASE STUDENTSHIP
The student will be supervised by a multi-disciplinary group with a wide range of expertise including geomorphological mapping, groundwater tracer testing, hydrogeological modelling, and groundwater resource management. The student will join the Institute of Applied Geoscience (IAG) at the University of Leeds, a highly multi-disciplinary institute with a strong international profile, including around 75 PhD students and postdoctoral researchers of multiple nationalities. Given that the studentship will be delivered in collaboration with an industry partner (Affinity Water), the successful applicant will be expected to spend a minimum of 3 months in a real-world setting at this company (in S. England); significant periods of fieldwork will also take place in the area (Chiltern Hills, N. of London).

FURTHER INFORMATION
You will be joining an interdisciplinary pool of supervisors (Dr. Jared West, Prof. Simon Bottrell from the School of Earth and Environment, University of Leeds, with Drs. Louise Maurice and Andrew Farrant, British Geological Survey; and Alister Leggatt, Affinity Water CASE supervisor). Please contact the lead supervisor ([Email Address Removed]) for further information related to the project or any other specific questions concerning what the successful applicant will be expected to do and required educational background. We encourage interested applicants to get in touch and arrange an informal skype meeting to discuss details of the project.