The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling
Riverbed temperature profiles are frequently used to estimate vertical river–aquifer exchange fluxes. Often in this approach, strictly vertical flow is assumed. However, riverbeds are heterogeneous structures often characterised by complex flow fields, possibly violating this assumption. We characte...
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2021-01-01
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author | Gert Ghysels Christian Anibas Henock Awol Abebe Debele Tolche Uwe Schneidewind Marijke Huysmans |
author_facet | Gert Ghysels Christian Anibas Henock Awol Abebe Debele Tolche Uwe Schneidewind Marijke Huysmans |
author_sort | Gert Ghysels |
collection | DOAJ |
description | Riverbed temperature profiles are frequently used to estimate vertical river–aquifer exchange fluxes. Often in this approach, strictly vertical flow is assumed. However, riverbeds are heterogeneous structures often characterised by complex flow fields, possibly violating this assumption. We characterise the meter-scale variability of river–aquifer interaction at two sections of the Aa River, Belgium, and compare vertical flux estimates obtained with a 1D analytical solution to the heat transport equation with fluxes simulated with a 3D groundwater model (MODFLOW) using spatially distributed fields of riverbed hydraulic conductivity. Based on 115 point-in-time riverbed temperature profiles, vertical flux estimates that are obtained with the 1D solution are found to be higher near the banks than in the center of the river. The total exchange flux estimated with the 3D groundwater model is around twice as high as the estimate based on the 1D solution, while vertical flux estimates from both methods are within a 10% margin. This is due to an important contribution of non-vertical flows, especially through the riverbanks. Quasi-vertical flow is only found near the center of the river. This quantitative underestimation should be considered when interpreting exchange fluxes based on 1D solutions. More research is necessary to assess conditions for which using a 1D analytical approach is justified to more accurately characterise river–aquifer exchange fluxes. |
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spelling | doaj.art-ef26dcb78516414b87985608b7b542612023-12-03T14:53:30ZengMDPI AGWater2073-44412021-01-0113330610.3390/w13030306The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater ModellingGert Ghysels0Christian Anibas1Henock Awol2Abebe Debele Tolche3Uwe Schneidewind4Marijke Huysmans5Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, BelgiumConnected Waters Initiative Research Centre, UNSW Sydney, Sydney, NSW 2052, AustraliaInstitute of Technology, Wollo University, Kombolcha, EthiopiaSchool of Water Resources and Environmental Engineering, Haramaya Institute of Technology, Haramaya University, Dire Dawa 138, EthiopiaSchool of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UKDepartment of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, BelgiumRiverbed temperature profiles are frequently used to estimate vertical river–aquifer exchange fluxes. Often in this approach, strictly vertical flow is assumed. However, riverbeds are heterogeneous structures often characterised by complex flow fields, possibly violating this assumption. We characterise the meter-scale variability of river–aquifer interaction at two sections of the Aa River, Belgium, and compare vertical flux estimates obtained with a 1D analytical solution to the heat transport equation with fluxes simulated with a 3D groundwater model (MODFLOW) using spatially distributed fields of riverbed hydraulic conductivity. Based on 115 point-in-time riverbed temperature profiles, vertical flux estimates that are obtained with the 1D solution are found to be higher near the banks than in the center of the river. The total exchange flux estimated with the 3D groundwater model is around twice as high as the estimate based on the 1D solution, while vertical flux estimates from both methods are within a 10% margin. This is due to an important contribution of non-vertical flows, especially through the riverbanks. Quasi-vertical flow is only found near the center of the river. This quantitative underestimation should be considered when interpreting exchange fluxes based on 1D solutions. More research is necessary to assess conditions for which using a 1D analytical approach is justified to more accurately characterise river–aquifer exchange fluxes.https://www.mdpi.com/2073-4441/13/3/306groundwater–surface water interactiontemperaturehydraulic conductivityheterogeneityMODFLOWBelgium |
spellingShingle | Gert Ghysels Christian Anibas Henock Awol Abebe Debele Tolche Uwe Schneidewind Marijke Huysmans The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling Water groundwater–surface water interaction temperature hydraulic conductivity heterogeneity MODFLOW Belgium |
title | The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling |
title_full | The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling |
title_fullStr | The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling |
title_full_unstemmed | The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling |
title_short | The Significance of Vertical and Lateral Groundwater–Surface Water Exchange Fluxes in Riverbeds and Riverbanks: Comparing 1D Analytical Flux Estimates with 3D Groundwater Modelling |
title_sort | significance of vertical and lateral groundwater surface water exchange fluxes in riverbeds and riverbanks comparing 1d analytical flux estimates with 3d groundwater modelling |
topic | groundwater–surface water interaction temperature hydraulic conductivity heterogeneity MODFLOW Belgium |
url | https://www.mdpi.com/2073-4441/13/3/306 |
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