Groundwater–Surface Water Interaction: Process Understanding, Conceptualization and Modelling (Proceedings of Symposium HS1002 at IUGG2007, Perugia, July 2007). IAHS Publ. 321, 2008, 46-53.

Determination of groundwater fluxes in the Belgian Aa River by sensing and simulation of streambed temperatures

CHRISTIAN ANIBAS¹, KERST BUIS², ADEM GETATCHEW¹,
OKKE BATELAAN^1,4, RONNY VERHOEVEN³ & PATRICK MEIRE²

1 Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel (VUB), 1050 Brussels, Pleinlaan 2, Belgium

canibas@vub.ac.be

2 Department of Biology, Ecosystem Management Research Group (ECOBE), University of Antwerp, B-2610 Antwerpen, Universiteitsplein 1, Belgium

3 Civil Engineering Department, Hydraulics Laboratory, University of Ghent, 9000 Ghent, Sint-Pieternieuwstraat 41, Belgium

4 Department of Earth and Environmental Sciences, KU Leuven, 3001 Leuven, Celestijnenlaan 200e, Belgium

Abstract Measurements of streambed temperature profiles are used to determine the vertical advective flow of water in the hyporheic zone in a Belgian lowland river. Quasi-steady-state simulations were performed with a one-dimensional heat transport equation introduced in the ecosystem modelling platform FEMME and then spatially interpolated. Measurement campaigns were performed in the winter season when a quasi steady-state thermal condition can be assumed. This allows an estimation of the mass balance of groundwater–surface water exchange in the study area. The results were compared with a steady-state MODFLOW 2000 simulation for the winter of 2004. Results show higher discharge in the upper reaches of the section and lower values in the downstream section of the river. Dependent probably on the water level of the river, the downstream section changes in time from gaining to losing.

Key words hyporheic zone; groundwater–surface water interaction; heat transport; FEMME