Surface and ground water interaction processes inside the Eau Blanche river basin (Dinant synclinorium – Belgium)
SPW – DG03, Avenue Reine Astrid, n° 39. B-5000 Namur
Department of Geology. University of Namur, Rue de Bruxelles, n° 61. B-5000 Namur
Department of Geology. University of Namur, Rue de Bruxelles, n° 61. B-5000 Namur
Abstract
Gauging river flows, measurement of in-situ parameters (such as electrical conductivity, pH and temperature) and major ions analysis were used to examine, at 8 selected sections, the groundwater inflow to the Eau Blanche River during a base flow recession period. Comparison of specific inflows between each section has permitted to identify positive and negative deviations, which were used to identify underground water inflows or outflows. Major ion analyses showed a clear evolution of river water chemical composition that could be related to the increasing amount of limestone aquifers composing the drainage area of the river. A simple two component mixing model confirmed the major influence of the limestone aquifer on the river chemistry; additional (probably anthropogenic) inputs of nitrates and chlorides were located.