Integral Flow Modelling Approach for Surface Water-Groundwater Interactions along a Rippled Streambed
by
Tabea Broecker 1,*, Katharina Teuber 1, Vahid Sobhi Gollo 1, Gunnar Nützmann 2,3, Jörg Lewandowski 2,3
and Reinhard Hinkelmann 1
and Reinhard Hinkelmann 1
1
Chair of Water Resources Management and Modeling of Hydrosystems, Technische Universität Berlin, 13355 Berlin, Germany
2
Ecohydrology Department, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587 Berlin, Germany
3
Geography Department, Humboldt-University Berlin, 10099 Berlin, Germany
*
Author to whom correspondence should be addressed.
Water 2019, 11(7), 1517; https://doi.org/10.3390/w11071517
Received: 18 June 2019 / Revised: 12 July 2019 / Accepted: 16 July 2019 / Published: 22 July 2019
(This article belongs to the Special Issue Groundwater-Surface Water Interactions)
Exchange processes of surface and groundwater are important for the management of water quantity and quality as well as for the ecological functioning. In contrast to most numerical simulations using coupled models to investigate these processes, we present a novel integral formulation for the sediment-water-interface. The computational fluid dynamics (CFD) model OpenFOAM was used to solve an extended version of the three-dimensional Navier–Stokes equations which is also applicable in non-Darcy-flow layers. Simulations were conducted to determine the influence of ripple morphologies and surface hydraulics on the flow processes within the hyporheic zone for a sandy and for a gravel sediment. In- and outflowing exchange fluxes along a ripple were determined for each case. The results indicate that larger grain size diameters, as well as ripple distances, increased hyporheic exchange fluxes significantly. For higher ripple dimensions, no clear relationship to hyporheic exchange was found. Larger ripple lengths decreased the hyporheic exchange fluxes due to less turbulence between the ripples. For all cases with sand, non-Darcy-flow was observed at an upper layer of the ripple, whereas for gravel non-Darcy-flow was recognized nearly down to the bottom boundary. Moreover, the sediment grain sizes influenced also the surface water flow significantly.
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Keywords:
groundwater-surface water interactions; integral model; computational fluid dynamics; hyporheic zone; OpenFOAM; ripples
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MDPI and ACS Style
Broecker, T.; Teuber, K.; Sobhi Gollo, V.; Nützmann, G.; Lewandowski, J.; Hinkelmann, R. Integral Flow Modelling Approach for Surface Water-Groundwater Interactions along a Rippled Streambed. Water 2019, 11, 1517.
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