Double-peaked breakthrough curves as a consequence of solute transport through underground lakes: a case study of the Furfooz karst system, Belgium

Curvas de avance de doble pico como consecuencia del transporte de soluto a través de lagos subterráneos: un estudio de caso del sistema de karst Furfooz, Bélgica

Courbes de restitution à double pics comme conséquence du transport de soluté à travers des lacs souterrains: le cas d’étude du système karstique de Furfooz, Belgique

Curvas de identificação de pico duplo como consequência do transporte de soluto através de lagoas subterrâneas: um estudo de caso do sistema cárstico de Furfooz, Bélgica

Lorraine Dewaide (1) , Pauline Collon (2) , Amaël Poulain (1) , Gaetan Rochez (1) , Vincent Hallet (1)

1 UNamur - Université de Namur [Namur]
2 GeoRessources

The existence of double-peaked breakthrough curves (BTC), which are the result of the transport of a dye tracer through underground lakes, is reported. Investigations were undertaken on the Furfooz karst sys- tem in southern Belgium. In this system, the River Lesse sinks partially into a swallow hole. The water follows a solitary conduit leading to an underground lake that is directly connected to a second underground lake. Double-peaked BTCs were detected in the resurgent wa- ter, downstream of this second lake. The report first de- scribes field data (tracer tests in various hydrologic con- ditions) which point towards the double peak being linked to a nonlinear process that originates within the lakes. Complementary investigations within the lakes show a complex behavior of the dye tracer related to a specific hydrodynamic feature that leads to the separation of the solute plume. A conceptual model of the solute transport within the lakes is proposed. This model emphasizes the physical effect of the lakes on the dye flow-through process.

Mots clés: Double-peaked breakthrough curve; Underground lake; Karst; Tracer tests; Belgium

Domaines: Géologie appliquée

Lorraine Dewaide, Pauline Collon, Amaël Poulain, Gaetan Rochez, Vincent Hallet. Double-peaked breakthrough curves as a consequence of solute transport through underground lakes: a case study of the Furfooz karst system, Belgium. Hydrogeology Journal, 2018, 26 (2), pp.641-650. ⟨10.1007/s10040-017-1671-4⟩. ⟨hal-01598417⟩