Water‐worked gravel beds in laboratory flumes – a natural analogue?

Cooper, James R ORCID: 0000-0003-4957-2774 and Tait, Simon J (2009) Water‐worked gravel beds in laboratory flumes – a natural analogue? Earth Surface Processes and Landforms, 34 (3). pp. 384-397. ISSN 0197-9337, 1096-9837

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Abstract

<jats:title>Abstract</jats:title><jats:p>An investigation has been conducted to identify the key parameters that are likely to scale laboratory sediment deposits to the field scale. Two types of bed formation were examined: one where sediment is manually placed and screeded and the second where sediment is fed into a running flume. This later technique created deposits through sequential cycles of sediment transport and deposition. Detailed bed surface topography measurements have been made over a screeded bed and three fed beds. In addition, bulk subsurface porosity and hydraulic conductivity have been measured. By comparing the four beds, results revealed that certain physical properties of the screeded bed were clearly different from those of the fed beds. The screeded bed had a random organization of grains on both the surface and within the subsurface. The fed beds exhibited greater surface and subsurface organization and complexity, and had a number of properties that closely resembled those found for water‐worked gravel beds. The surfaces were water‐worked and armoured and there was preferential particle orientation and direction of imbrication in the subsurface. This suggested that fed beds are able to simulate, in a simplified manner, both the surface and subsurface properties of established gravel‐bed river deposits. The near‐bed flow properties were also compared. It revealed that the use of a screeded bed will typically cause an underestimation in the degree of temporal variability in the flow. Furthermore, time‐averaged streamwise velocities were found to be randomly organized over the screeded bed but were organized into long streamwise flow structures over the fed beds. It clearly showed that caution should be taken when comparing velocity measurements over screeded beds with water‐worked beds, and that the formation of fed beds offers an improved way of investigating intragravel flow and sediment–water interface exchange processes in gravel‐bed rivers at a laboratory scale. Copyright © 2008 John Wiley &amp; Sons, Ltd.</jats:p>

Item Type:	Article
Additional Information:	## TULIP Type: Articles/Papers (Journal) ##
Uncontrolled Keywords:	3707 Hydrology, 3709 Physical Geography and Environmental Geoscience, 37 Earth Sciences, 3705 Geology
Depositing User:	Symplectic Admin
Date Deposited:	12 Dec 2017 08:27
Last Modified:	07 Dec 2024 13:27
DOI:	10.1002/esp.1743
Related URLs:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3013951