Thesis defence by Romain Deleu

Title: Hydrodynamics of solute transport in karst conduits: assessment by multi-point dye tracing and numerical modelling

A tracer test is a field methodology widely used in hydrogeology, particularly to characterise underground flows in karstic environments. It involves injecting a tracer into a river, leak or well, a substance that can be detected downstream by a measuring device. The most common tracers are fluorescent substances such as fluorescein, which can be easily detected by field fluorometers. Conventional tracing methodology involves the use of a single fluorometer, which is often placed on the side of the river, close to the bank, for ease of access. The development of new compact, autonomous and inexpensive fluorometers has made it possible to carry out ‘multipoint’ tracings, i.e. tracings involving the use of several fluorometers placed across a section of underground river. Recent studies have shown that the position of the device seems to have a significant impact on the quality of the result, and the aim of this thesis is to quantify the signal heterogeneities as a function of the position of the device. This methodology was applied to several karstic sites in Wallonia.

More information in French.

Romain will present the results of his PhD thesis, conducted in the Department of Geology under the supervision of Vincent Hallet.