Sediment Transport In River Channels At High Stage
PhD thesis by Brown, F.A., 1997

Mainly experimental work, using the Flood Channel Facility (FCF) at HR Wallingford, as part of a team of researchers, aimed at investigating sediment transport in compound channels. Detailed velocity and boundary shear stress data were collected, together with sediment transport rates at various depths of inundation on the floodplain. The floodplain was later roughened with dowels to make it more representative of natural floodplains. A uniform sand size was used, with d35 = 0.8 mm. The same sand size was used in the smaller flumes at the universities of Birmingham (PhDs of Ayyoubzadeh, Atabay and Tang) and Ulster (Myers et al.).

Abstract

The development of theoretical work has been reviewed, beginning with the earliest equations describing simple prismatic channels up to the latest attempts to model three-dimensional phenomena. Inadequacies in present day knowledge have been discussed. In particular the lack of field and laboratory data is highlighted.

Previous phases of work on the Flood Channel Facility, commissioned by the EPSRC and completed in 1986, have studied channels with fixed boundaries. Researchers on the current phase, Phase C, studied a straight channel with a mobile bed. A detailed description of the experimental apparatus, including calibration, has been provided. Logistical difficulties are discussed and the experimental procedures adopted as a consequence are explained. Measurements were taken of water surface slope, sediment concentration, velocity, boundary shear stress, bed profile and dune migration rates. The errors in the data are assessed and the results are presented graphically and with tabulated summaries.

Manning's equation has been applied to the channel zones to give values of main channel and flood plain resistance. Corrections for sidewall interference have been applied, giving a value of resistance on the mobile bed alone. This value has been further reduced to its form and grain components. A comparison has been made with predictions by the alluvial friction theories of White, Paris and Bettess, and van Rijn. Sediment load data, measured by an infra-red sediment monitor, have been analysed and empirical equations have been derived. The data have been compared with the sediment transport theories of Ackers and White, van Rijn, and Meyer-Peter and Muller. A preliminary analysis of the characteristics of the bedforms has been presented and an assessment has been made of the wisdom of the initial choice of sediment size.

The stage-discharge relationship has been approximated using a simple divided channel method.This was then improved using the coherence method. Finally the two-dimensional depth-averaged model of Knight and Shiono was applied to the data.

Data files

Here are experimental data carried out by Brown on FCF in which the main channel had a mobile bed and the floodplains were either smooth or rough. Details on the notation and programme are given in Notes on FCF data. Data files are in Microsoft Excel format, which are regrouped and listed in the following manner. All files need to be unzipped using WINZIP and then opened with Excel. The summary of experimental data see TABLE.

Data file links

General data

  • FCF files (summary data, inbank, overbank with smooth and rough floodplain)

Overbank (smooth floodplain)

Overbank (rough floodplain)

Publications

  • Knight, D.W., Brown F.A., Ayyoubzadeh S.A. and Atabay, S., 1999, Sediment transport in river models with overbank flow, In River Sedimentation [Eds A W Jayawardena, J H W Lee and Z Y Wang], Proc. Seventh International Symposium on River Sedimentation, Hong Kong, 16-18 December 1998, Balkema, 19-25. [C]
  • Myers W. R. C., Knight, D.W., Lyness, J.F., Cassells, J. and Brown, F.A., 1999, Resistance coefficients for inbank and overbank flows, Proc. Instn. of Civil Engineers, Water, Maritime and Energy Division, London, Vol. 138, Issue 2, June, 105-115. [J]
  • Knight, D.W., Brown, F.A., Valentine, E.M., Nalluri, C., Bathurst, J.C., Benson, I.A., Myers, W.R.C., Lyness, J.F., and Cassells, J.B., 1999, The response of straight mobile bed channels to inbank and overbank flows, Proc. Instn. of Civil Engineers, Water, Maritime and Energy Division, London, Vol. 136, Dec., 211-224. [J]
  • Knight, D.W. and Brown, F.A., 2001, Resistance studies of overbank flow in rivers with sediment using the Flood Channel Facility, Journal of Hydraulic Research, IAHR, Vol. 39, No. 3, 283-301. [J]