Environmental Engineering Research Centre
School of Planning, Architecture and Civil Engineering

Joshua Thompson



Critical Source Areas in Irish Catchments: a combined top down, bottom up approach. (Primary advisor: Dr. Donnacha Doody, AFBI) 

My PhD is based within the Agri-Environmental Science Department of the Agri-Food & Biosciences Institute, in collaboration with Trinity College, Dublin and University College, Dublin. My research examines the impact and occurrence of critical source areas (CSAs) of sediment and associated pollutants in Irish catchments. Using a bottom up approach, the dynamics of variable contributing areas of the overland flow network, and resultant chemistry at the hillslope scale tests the CSA hypothesis in the Irish context. By understanding how micro-terrain attributes influence the frequency of overland flow at a given point along a hillslope, and the influence of storm characteristics and antecedent conditions on runoff quality, catchment scale (top down) work is informed. Using a top down approach, connectivity modelling in two catchments (Co. Louth and Co. Down) of differing ecological status is coupled with inverse modelling of 2 years of geochemical tracing data. This approach pin-points CSAs within an bayesian uncertainty framework. Continuous monitoring of water quality and sediment using field calibrated turbidity sensors, is used to understand differences in transfer and connectivity and the frequency duration of excessive sediment levels within the GLUE framework.


"Dynamics of critical source areas: does connectivity explain chemistry?" (2012)  J.J.D. Thompson., D.G. Doody., R. Flynn., C.J. Watson Science of the Total Environment, In Press