Poison rivers may be grim legacy of flood disaster

Exclusive DANGEROUS chemicals released during centuries of heavy industry could be polluting Yorkshire again after being dredged up in last summer's floods, new research reveals.

Academics at a three-day conference looking at the effects of last June's torrential downpour warned that flooding would become an increasingly important issue in the years and decades to come – and that only widescale change to the way we live will help mitigate the devastating impact.

Floodplains need to be abandoned, new lakes created, hill farming scaled back, new homes built to the highest environmental standards and woodland regrown as Britons stop waging war with nature and allowed the country to return to its natural state, they argued.

And farmers need to be made "custodians of the countryside", being adequately compensated for allowing flood waters on to their land to ruin their crops in order to save towns and cities further downstream, the academics said.

Most pressing of all, however, could be dealing with the long-term effects of the recent floods.

Sheffield Hallam University academic Ian Rotherham, who co-ordinated the conference, said: "Our research has shown that extreme floods can release dangerous pollution locked up in valley-bottom sediments from centuries of heavy industry.

"In some parts of the country like South and West Yorkshire this may mean heavy metals and other pollutants released from deposits to be spread far and wide across floodlands downstream.

"These could be farming or housing lands and clearly raises concerns."

He said that in river catchments like the Rother in North Derbyshire and South Yorkshire – once the second-most polluted river in Western Europe – pollutants such as lead, zinc, cadmium, mercury and dioxins were pumped in from the textile mills and steel industry of the 19th and 20th centuries.

"Research at Sheffield Hallam University showed how the floods in the year 2000 scoured out the sediments to release the toxins downstream," said Dr Rotherham. "The hope is that the sheer volume of water has diluted the impacts.

"However, this is not known for certain, but it is clear that very nasty chemicals have been re-released and have ended up somewhere downstream."

With the floods of 2007 at a far greater level than those of 2000 – and far more widespread – the spread of dangerous toxins is likely to have been far worse.

Dr Rotherham said another problem that has not been confronted is the spread of invasive, alien species, particularly Japanese Knotweed, Giant Hogweed and Himalayan Balsam that until last summer's floods were contained to rivers in urban areas.

"Recent floods are now spreading these species far and wide, so we can expect an exponential increase in the problem over the next few years.

"They all thrive on disturbance, and the floods bring that with a vengeance, and the potential long-term costs will be enormous.

"In decades to come, the costs of cleaning this up could run into millions of pounds. So far there is no strategy for assessment, monitoring and control."

Sheffield-based environmentalist and TV presenter Chris Baines said that the loss of broadleaved woodland combined with the draining and intensive farming of arable land had made the British countryside far less water-retentive, forcing land downstream to flood.

"There is no single magic bullet, but there is one overarching policy change that needs to be embraced," he said.

"There is a need to integrate policy and practice across entire river catchments, from the summit to the sea, with the aim of restoring the natural absorbency and water-holding capacity of the landscape wherever possible."

He said that could be done through farming fields less intensively; planting more trees and covering roofs with vegetation in urban areas; and forcing water companies to spend more money on upkeep in the hills rather than concentrating downstream in the towns and cities.

Rob Stoneman, of the Yorkshire Wildlife Trust, said: "It comes down to a cost-benefit analysis.

"Society takes a risk when it over-grazes the uplands, paves over urban green space, develops in the floodplain or drains coastal wetlands.

"It mitigates that risk by building flood defences for the most valuable, built-upon land and tacitly accepts inevitable failure every 100 years or so."

But Mr Stoneman said that the latest research suggested that floods which are now considered one in 200 year events, like last summer, might happen once a decade by 2080.