Page 261 - Fundamentals of Geomorphology

244 PROCESS AND FORM

elsewhere in river systems, produced a spur for changes in climate, vegetation cover, and land-use. Many river
management practices. Mounting evidence and theory valleys record a history of changing conditions during
demanded a geomorphological approach to river man- the last 10,000 years, induced by changing climates and
agement (e.g. Dunne and Leopold 1978; Brookes 1985). changing land-use, that have produced adjustments in
Thus, to control bank erosion in the UK, two major the fluvial system. Human agricultural, mining, and
changes in the practices and perceptions of river man- urban activities cause changes in rivers. Overall, they
agers took place. First, they started thinking about bank increase the flux of fluvial sediments. Dams affect stream-
erosion in the context of the sediment dynamics of flow, sediment transfer, and channel form downstream.
whole river systems, and began to examine upstream and Human actions modify many rivers, which need manag-
downstream results of bank protection work. Second, ing. Fluvial geomorphology lies at the heart of modern
they started prescribing softer, more natural materials river management.
to protect banks, including both traditional vegetation,
such as willow, osier, and ash, and new geotextiles to ESSAY QUESTIONS
stimulate or assist the regrowth of natural plant cover
(Walker 1999). River management today involves scien- 1 How would you convince a sceptical
tists from many disciplines – geomorphology, hydrology, friend that rivers carved the valleys
and ecology – as well as conservationists and various user they flow through?
groups, such as anglers (e.g. Douglas 2000). Thus, in
Greater Manchester, England, the upper Mersey basin 2 Why do river channel patterns vary?
has a structure plan that incorporates flood control, habi- 3 To what extent have humans
tat restoration, and the recreational use of floodplains; modified fluvial landscapes?
while, in the same area, the Mersey Basin Campaign
strives to improve water quality and river valley ameni-
ties, including industrial land regeneration throughout
the region (Struthers 1997). FURTHER READING

Acreman, M. (2000) The Hydrology of the UK: A Study
SUMMARY of Change. London: Routledge.
Not strictly geomorphology, but highly relevant to the
subject.
Flowing water is a considerable geomorphic agent in
most environments, and a dominant one in fluvial envi- Bridge, J. S. (2003) Rivers and Floodplains: Forms,
ronments. It carves many erosional landforms, including Processes, and Sedimentary Record. Oxford:BlackwellSci-
rills and gullies, bedrock channels, and alluvial chan- ence.
nels. River profiles, drawn from source to mouth, are A useful text for more advanced readers.
normally concave, although they often possess knick-
pointsmarked by steepergradients. Rivers form networks Brookes, A. J. and Shields, F. D. (1996) River Channel
Restoration: Guiding Principles for Sustainable Projects.
that may be described by several geometrical and topo-
logical properties. Valleys are an overlooked erosional Chichester: John Wiley & Sons.
landform. Flowing water deposits sediment to build If you are interested in applied fluvial geomorphology,
many depositional landforms. The smallest of these are try this.
features on channel beds (riffles and dunes, for exam- Jones, J. A. A. (1997) Global Hydrology: Process, Resources
ple). Larger forms are floodplains, alluvial fans, playas, and Environmental Management. Harlow, Essex:
river terraces, and lake deltas. Flowing water is sensitive Longman.
to environmental change, and especially to changes of Gives a hydrological context for fluvial processes.