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‘It stands to reason’, said the farmer, ‘we’ve only had these quick, high floods
since the foresters ploughed those hills up there.’
This man’s knowledge of, dependence on, and reaction to his local river
made his reasoning easy. Yet to a government hydrologist, as was the author at
the time of the conversation, proof of a link between preparing upland soils for
successful afforestation and a change in the unit hydrograph for the basin
would take a decade of expensive research. After its completion the logical
outcome of the proven link, between land there and water here, i.e. modifying
forestry practice, compensating the farmer or afforesting a less sensitive
hillside, would not translate into public policy. There were simply no riverrelated land planning policies in many countries; the UK was no exception.
The outcome was that local authority engineers built the farmer a bridge
over the newly flood-prone stream. Perhaps it is the heroic talent of the civil
engineer to solve in this way point problems where they arise which has
discouraged the ‘look upstream’ mentality of the local, the peasant, the river
enthusiast. Societies have built dams, canals, flood walls, bridges and other
structures to ‘stabilise’ river systems without questioning the cause of the
instability. Rather like early technical medicine, we have used the equivalents
of drugs and pain-killers to cure ‘now’ problems whereas some claim the true
human talent lies with holism and the longer term.
This book tries to assemble a body of knowledge which supports a very
broad approach to river problems; physically destabilised river systems will be
a major theme but polluted and biologically sterilised systems are all
amenable to ‘the treatment’. At the other extreme, there is increasing demand
to conserve, by management intervention, those relatively few pristine
wilderness river systems which remain.
‘The treatment’ as a concept comes relatively easily to the geographer.
Fluvial geomorphology, a major feature of geographical research in the
second half of this century, has provided chapter and verse on the natural
dynamics of the river basin, which function to transfer water and sediments to
the ocean, leaving a characteristic morphology—river channel, floodplain,
valley side—to form the basis of river habitat. While the engineer has applied knowledge of precise physical laws to the ‘now’ problems of river basins for
millennia, the geomorphological view puts these laws into the context of their
boundary conditions in a variety of global environments, at a variety of scales, and, most critically for enlightened management, over a range of timescales. |
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