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www.hydrol-earth-syst-sci-discuss.net/5/2199/2008/
doi:10.5194/hessd-5-2199-2008
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under the Creative Commons Attribution 3.0 License.
Influence of aquifer and streambed heterogeneity on the distribution of groundwater discharge
1Eberhard Karls University of Tübingen, Centre for Applied Geoscience, Germany
2UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Informatics, Germany
3UFZ, Helmholtz Centre for Environmental Research , Dept. of Hydrogeology, Germany
4École Polytechnique Montreal, Dept. of Civil, Geological and Mining Engineering, Canada
5University of Applied Sciences Magdeburg-Stendal, Dept. of Water and Recycling Management, Germany
6EAWAG, the Swiss Federal Institute of Aquatic Science and Technology, Dept. of Water Resources and Drinking Water, Switzerland
Abstract. The spatial distribution of groundwater fluxes through a streambed can be highly variable, most often resulting from a heterogeneous distribution of aquifer and streambed permeabilities along the flow pathways. In a previous study, observed temperature profiles in the streambed of a small stream in Germany were used to calibrate the subsurface parameters of a groundwater flow and heat transport model of the stream-aquifer system. Based on the model results, we defined four scenarios to simulate and assess the interplay of aquifer and streambed heterogeneity on the distribution of groundwater fluxes through the streambed: (a) a homogeneous low-K streambed within a heterogeneous aquifer; (b) a heterogeneous streambed within a homogeneous aquifer; (c) a well connected heterogeneous low-K streambed within a heterogeneous aquifer; and (d) a poorly connected heterogeneous low-K streambed within a heterogeneous aquifer. The results showed that the aquifer has a stronger influence on the distribution of groundwater fluxes through the streambed than the streambed itself. However, a homogeneous low-K streambed, a case often implemented in regional-scale groundwater flow models, resulted in a strong homogenization of fluxes, which may have important implications for the estimation of peak mass flows. The simulation results with heterogeneous low-K streambeds, whether or not well connected to the aquifer, were similar to the results of the base case scenario without a separate parameterization of the streambed, despite the lower permeability. We conclude that predictions of water flow and solute transport may significantly benefit from heterogeneous distributions of both aquifer and streambed properties in numerical simulation models.
Discussion Paper (PDF, 1427 KB) Interactive Discussion (Closed, 3 Comments) Final Revised Paper (HESS)
Citation: Kalbus, E., Schmidt, C., Molson, J. W., Reinstorf, F., and Schirmer, M.: Influence of aquifer and streambed heterogeneity on the distribution of groundwater discharge, Hydrol. Earth Syst. Sci. Discuss., 5, 2199-2219, doi:10.5194/hessd-5-2199-2008, 2008. Bibtex EndNote Reference Manager XML
