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Intra‐meander hyporheic flow in alluvial rivers
Author(s) -
Revelli Roberto,
Boano Fulvio,
Camporeale Carlo,
Ridolfi Luca
Publication year - 2008
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007081
Subject(s) - meander (mathematics) , sinuosity , geology , hyporheic zone , hydrology (agriculture) , fluvial , alluvium , flow (mathematics) , geomorphology , alluvial plain , bedform , sediment transport , sediment , geotechnical engineering , geometry , paleontology , mathematics , structural basin
Several geomorphological fluvial features are able to induce hyporheic exchange between the rivers and the alluvial sediments. However, while the small‐scale exchange induced by bed forms has been thoroughly investigated, the role of the larger features remains poorly understood. Here, we focus on the hyporheic flows driven by the channel sinuosity in the intrameander zone. A physically based model is adopted to simulate the morphodynamic evolution of three different meandering rivers, from the first stages of the meander evolution until the incipient meander cutoff. For each stage, the sinuosity‐driven intrameander hyporheic flow is computed. In this way, the hyporheic flow field, the fluxes exchanged with the river, and the residence times are described during the whole meander evolution. The main result concerns the existence of a remarkable zonation induced by the flow field in the intrameander zone. The more the meander evolves, the more the zonation becomes pronounced, and the probability distribution of the residence times shows a bimodal shape with an intermediate power law behavior. Some general rules governing the typical timescales of the intrameander hyporheic flow and the mean exchanged flux are also deduced.