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WATER RESOURCES RESEARCH, VOL. 44, W03418, doi:10.1029/2007WR006506, 2008

Comparison of hyporheic exchange under covered and uncovered channels based on linked surface and groundwater flow simulations

M. Bayani Cardenas

Department of Geological Sciences, University of Texas at Austin, Austin, Texas, USA


Michael N. Gooseff

Department of Civil and Environmental Engineering, Pennsylvania State University, University Park, Pennsylvania, USA


Abstract

Hyporheic exchange is an important process upon which stream biogeochemical cycling is dependent. The potential for hyporheic exchange in covered channels (i.e., ice-covered channels, karst conduits, fractures) with permeable sediments has not yet been assessed. We characterize the potential for hyporheic exchange in covered channels using linked turbulent channel flow/groundwater flow simulations. Simulations show that hyporheic exchange occurs in covered channels which have shallower hyporheic zones and larger hyporheic fluxes than equivalent-depth equivalent-discharge uncovered channels. We also analyzed hyporheic exchange for the case of freely floating covers with rough undersides and found that hyporheic exchange decreases with increasing cover roughness which in turn is driven by subdued bed topography, a response to additional resistance due to covers. The results suggest that hyporheic exchange occurs in covered channels and may be just as or perhaps more important to the ecology and biogeochemistry of these channels than to open channel streams.

Received 9 September 2007; accepted 16 January 2008; published 15 March 2008.

Keywords: ice cover; bed forms; hyporheic zone; FLUENT; COMSOL; computational fluid dynamics.

Index Terms: 1830 Hydrology: Groundwater/surface water interaction; 1829 Hydrology: Groundwater hydrology; 1860 Hydrology: Streamflow; 0738 Cryosphere: Ice (1863); 0744 Cryosphere: Rivers (0483, 1856).

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Citation: Cardenas, M. B., and M. N. Gooseff (2008), Comparison of hyporheic exchange under covered and uncovered channels based on linked surface and groundwater flow simulations, Water Resour. Res., 44, W03418, doi:10.1029/2007WR006506.