River engineering to control the flow of water across ancient flood plains could not have prevented the deluge in northern Europe, according to a British expert in river regulation.
Geoff Petts, professor of geography at Birmingham University, said the floods were so vast that nothing could have stopped what is after all a natural phenomenon. River engineering in northern Europe has not exacerbated the floods significantly, he said.
``The problem is that the cost of such floods is made much greater by people building in the flood plain. They do this because the river engineering has made them feel more secure. The general rule is that with floods of this scale it doesn't matter how many reservoirs, dams and dykes you build, you'll still get flooding in extreme weather conditions.''
Mild temperatures, which have melted snow in the Alps, and a succession of low-pressure systems blowing from the Atlantic have caused the ground of most of northern Europe to be ``absolutely sodden'', said Duncan Reed, a flood and storm researcher at theInstitute of Hydrology, Wallingford. ``Because the ground is so ripe for floods, all it takes is a little more rain to tip the balance and the only place for the water to go is into the rivers.''
Professor Petts said the Rhine was one of the first rivers to undergo ``canalisation'', in which the river is forced to flow through a single deep channel instead of two or more channels which can easily overflow into a natural flood plain. As a result, about 90 per cent of former wetlands has been drained.
Since the early nineteenth century engineers have straightened the river to help navigation and make the river run faster when floods are likely. The long-term dilemma for the Netherlands is to decide whether a large secondary channel should be cut to divert floodwater in times of crisis, which is what would have happened naturally. ``The only alternative is to build embankments higher and higher in the knowledge that some day they will be breached, with devastating consequences,'' Professor Petts said.
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