The fear that the UK may be subject to increasing large scale flooding because of climate change has led to a new research programme to manage rivers through their entire length.
A £5.5m programme will bring engineers, scientists and government agencies together, partly to avoid the current situation where a flood relief scheme can shift the water from one community to another causing new problems.
But the major problem is that climate change means Victorian drainage systems are no longer up to dealing both with urban sprawl and heavier rain. In the past five years a spate of floods and sewage washing into houses has led to fears for public health. Two million properties are at risk.
One problem being investigated is the impact of the common agricultural policy on upland areas where some of Britain's longest rivers rise. Towns sometimes 50 or more miles downstream face flooding days after rainfall when a sudden rise in river levels swamps their defences.
An example is the river Severn which has its source in the Welsh mountains. Historically this area of bogs, moors and woods soaked up the rain like a sponge and released it gradually over many weeks.
A combination of agricultural practices which led to the ploughing up of pasture and removal of hedges, and ever increasing levels of stock has meant that the rain runs off directly into the rivers causing flooding downstream.
Howard Wheater, of Imperial College, London, is leading a project in Pontbren near Newport in the Severn catchment to try to get the land to soak up rain again. He said: "It seems improbable at first sight that putting larger numbers of a heavier type of sheep on land in the Welsh hills could help cause flooding problems in Tewkesbury in Gloucester but it appears it is true. It is not the whole cause, obviously, but the ground is compacted and the vegetation so low that the rain just runs off as if it was concrete. My standard teaching has been that pasture soaks up the water, but this appears not to be so."
Many of the Welsh pastures were also drained as a result of attempts to increase quality of grassland and plant conifer forests on former bogland.
A farmers' cooperative in Pontbren is so concerned about the way its countryside has changed for the worse as a result of the common agricultural policy it is changing farming methods, including moving to a lighter breed of sheep and far lower stocking levels. Trees are also being planted alongside rivers to break up the ground and hold back the rain.
The project's urban task force is trying to devise a method of avoiding flood water flushing out the sewers.
Ian Cluckie from the University of Bristol said he hoped that some practical solutions would be provided within a year but the principal task of the consortium was to get researchers, geographers, civil engineers and those concerned with social issues together to provide solutions for the whole catchment area of rivers. The problems were made worse in the south-east of England by John Prescott's policy of building new settlements. Large new areas of concrete would lead to more flooding risks.
One of the more thorny problems discussed at the conference was the new estates that had been built in flood plains in the past 20 years, some of which were likely to be subject to regular inundation.
Professor George Fleming, a civil engineer from EnviroCentre, said the simplest and best solution would be to "remove certain settlements altogether".