IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Characterising the effect of increasing riverbank vegetation on the flow field across the channel
Characterising the effect of increasing riverbank vegetation on the flow field across the channel
Author : MANOUSOS VALYRAKIS(1), DA LIU(1), NICHOLAS JAMES MCGANN(1, 2), UMUT TURKER(3), ORAL YAGCI(4)
ABSTRACT
Over the last two decades, the role of vegetation in the environmental and ecological restoration of surface water bodies
has received much attention. Numerous studies have investigated the effects of vegetation on flow velocity at various
locations ranging from the floodplain, river-bank and main channel. There is a general agreement amongst such studies,
that the presence of vegetation may cause a decrease in flow velocity locally, followed by increased flows laterally, in
non-vegetated regions. This experimental study attempts to present the findings of an elaborate set of flow
measurements that aim at quantifying changes to the flow field at the main channel, at the bank inside the vegetated
region and at their interface, for increasing vegetation density. To this goal an inclined section is constructed with acrylic
panels sloping at, in a 1.8m wide re-circulating flume, to simulate the stream-bank. The main-channel bed comprises of
coarse sand of 1.5mm nominal diameter, while 6mm diameter acrylic rods are used to simulate the vegetated riverbank.
Ten velocity and turbulent intensity profiles are developed across the test cross-section, for each vegetation
density, via acoustic Doppler velocimetry. The experiments are run under uniform flow and stable bed conditions, for a
range of six different vegetation densities changed by adding more vegetation elements in a staggered arrangement
along the stream-bank. These detailed observations are further analyzed, with emphasis on the effects on the main
channel. Measurements near the bed with implications for sediment transport are further discussed.
File Size : 685,788 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 20/08/2015
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