Environmental Engineering Reference
In-Depth Information
management of future sediment dynamics and
associated flood risks may be reduced to a level
that is acceptable or, at least tolerable.
limited support is offered via a discussion board
that can be found on the CAESAR website. This
means that the development of the code can be
somewhat ad hoc and sporadic, and that the level
of user support provided cannot match that avail-
able for a commercial package. However, this
approach does mean that CAESAR is freely avail-
able for download from Tom Coulthard's website
(http://www.coulthard.org.uk).
Acknowledgements
The Sediment Toolbox featured herein was de-
veloped as part of a multi-disciplinary research
project undertaken by the Flood Risk Manage-
ment Research Consortium (www.floodrisk.org.
uk). In its first phase, the Consortium was funded
by the UK Engineering and Physical Sciences
Research Council under grant GR/S76304/01,
with additional contributions from the Defra/EA
Joint R&D programme on Flood and Coastal
Defence, the Scottish Executive, the Rivers
Agency (Northern Ireland) and UK Water Indus-
try Research.
Closure
The tools outlined here span a range of require-
ments in terms of the data, technical expertise
and resources (time and money) necessary to
support their application; they generate output
resolutions that range from indicative to diagnos-
tic; and they can be applied at spatial scales from
river reaches to whole catchments. They are,
consequently, suitable for addressing a wide
range of sediment-related issues in flood risk
management.
None of the tools is perfect; indeed, all are
subject to potentially serious errors through mis-
application, and uncertainties in their outcomes
remain large. In describing them, the authors have
been careful not to exaggerate their capabilities
and to be candid in reporting their limitations.
They have done this because individuals intend-
ing to perform sediment assessment, analysis or
modelling-related investigations and those who
are the end users of their outputs must understand
that broad-scale sediment dynamics are difficult
to characterize and even more challenging to
quantify or predict. So why attempt this?
Because quite simply, the weight of evidence sug-
gests that future sediment-related flood risks are
far
References
Ackers, P. (1993) Sediment transport in open channels:
Ackers and White update. Proceedings of the Institu-
tion of Civil Engineers Water, Maritime and Energy,
101, 2041-2060.
Ackers, P. and White, W.R. (1973) Sediment transport:
new approach and analysis. Journal of Hydraulics
Division, American Society of Civil Engineers, 99,
2040-2060.
Bagnold, R.A. (1966) An Approach to the Sediment
Transport Problem from General Physics. United
States Geological Survey, Professional Paper 422.
Bagnold, R.A. (1980) An empirical correlation of bedload
transport rates in flumes and natural rivers. Proceed-
ings of the Royal Society A405, 369-473.
Bettess, R. and White, W.R. (1981) Mathematical simu-
lation of sediment movement in streams. Proceedings
of the Institution of Civil Engineers, 71, part 2,
879-982.
Biedenharn, D.S., Gibson, S.A., Little, C.D., Jr., Mooney,
D.M., Thorne, C.R., Wallerstein, N.P and Watson,
C.C. (2006) Sediment Impact Assessment Model
(SIAM) In: Wallerstein, N. (ed.) Accounting for Sedi-
ment in Rivers - A Tool Box of Sediment Transport
and Transfer Analysis Methods and Models to Sup-
port Hydromorphologically-Sustainable Flood Risk
Management in the UK. Flood Risk Management
too important
to be ignored (Lane and
Thorne 2007, 2008).
Selection of a method or model appropriate to
the task at hand is a crucial first step in any
sediment analysis. In this context, it is vital that
users weigh the need to perform the work in a
timely and cost-efficient manner against the na-
ture, extent and severity of potential sediment-
related risks, so that uncertainty regarding the
