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Flow interaction with dynamic vegetation patches: implications for biogeomorphic evolution of a tidal landscape

Authors :
Vandenbruwaene, Wouter
Temmerman, Stijn
Bouma, T.J.
Klaassen, P.C.
de Vries, M.B.
Callaghan, D.P.
van Steeg, P.
Dekker, F.
van Duren, L.A.
Martini, E.
Balke, T.
Biermans, G.
Schoelynck, Jonas
Meire, Patrick
Faculty of Engineering Technology
Marine and Fluvial Systems
Spatial Ecology
Source :
Journal of geophysical research: Earth surface, 116(F1). Wiley-Blackwell, Journal of Geophysical Research, 116:F01008. American Geophysical Union, Journal of geophysical research
Publication Year :
2011

Abstract

Feedback between vegetation growth, water flow, and landform is important for the biogeomorphic evolution of many landscapes, such as tidal marshes, alluvial rivers, and hillslopes. While experimental studies often focus on flow reduction within static homogeneous vegetation, we concentrate on flow acceleration around and between dynamically growing vegetation patches that colonize an initially bare landscape, with specific application to Spartina anglica, a pioneer of intertidal flats. Spartina patches were placed in a large-scale flow facility of 16 × 26 m, simulating the growth of two vegetation patches by increasing the patch diameter (D = 13 m) and decreasing the interpatch distance (d = 2.30 m). We quantified that the amount of flow acceleration next to vegetation patches, and the distance from the patch where maximum flow acceleration occurs, increases with increasing patch size. In between the patches, the accelerated flow pattern started to interact as soon as D/d ≥ 0.430.67. As the patches grew further, the flow acceleration increased until D/d ≥ 6.6710, from which the flow acceleration between the patches was suppressed, and the two patches started to act as one. These findings are in accordance with theory on flow around and between nonpermeable structures; however, the threshold D/d values found here for permeable vegetation patches are higher than those for nonpermeable structures. The reported flow interactions with dynamic vegetation patches will be essential to further understanding of the larger-scale biogeomorphic evolution of landscapes formed by flowing water, such as tidal flats, floodplain rivers, and hillslopes.

Details

Language :
English
ISSN :
21699003 and 01480227
Database :
OpenAIRE
Journal :
Journal of geophysical research: Earth surface, 116(F1). Wiley-Blackwell, Journal of Geophysical Research, 116:F01008. American Geophysical Union, Journal of geophysical research
Accession number :
edsair.dedup.wf.001..29e0784fbfe1b66d4136ad85d507ea3d