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Professor Alastair Borthwick, Professor of Engineering Science, University of Oxford, said:
“The rainfall events last Friday were unusual in that the cloud system remained nearly stationary for a considerable length of time, resulting in about 100 mm rainfall depths occurring across the Midlands and part of Wales. Similar levels of heavy localised rainfall have occurred during the past hundred years – for example, 110 mm in an hour at Wheatley near Oxford in 1910, 140 mm in 2 hours at Hampstead, London in 1975, 178 mm in 3 hours in Lincolnshire in 1960, 200 mm in 8 hours in Somerset in 1917. In my opinion, although Friday’s events are extreme, they are not greatly out of line with previous recorded largest rainfall events.
“We simply do not have enough data to judge whether climate change is a factor in these events. Moreover, the fluid dynamics of weather systems is highly nonlinear, making it almost impossible for meteorologists to forecast accurately more than a few days in advance.
“I do not think we can do much to prevent such events from happening. What we can do however is to estimate risk levels and assess possible countermeasures according to the assets under threat. This is very much inline with the Foresight report on Future Flooding commissioned by the OST in 2004.
“One heartening aspect has been the willingness of people to help each other. There are lessons to be learnt however, perhaps by looking at how other countries handle large-scale flood events. The emergency services would benefit from support at an earlier stage from the army, etc (as is done in China where flood events are much more severe).
“Improved communication to the public about the state of the transport system is needed. It is not sufficient to rely on postings to websites (which many people are unable to access). There is a need to educate people about flood risk and for the country to train sufficient water engineers. Far too many new properties have been constructed on the floodplains, and are virtually uninsurable. Much of our municipal infrastructure is old and in need of renovation. Investment is needed in drainage systems.”
Dr Barnaby Smith, Centre for Ecology & Hydrology, said:
“The last few weeks have seen a truly exceptional series of events. Very unusual weather conditions across much of the UK have persisted throughout the summer of 2007, leading to the highest May and June combined rainfall total on record. It is unusual for soils to be close to saturation point at this time of year, and this in combination with several days of intense rainfall has lead to flooding that has no close modern parallel.
“In the medium term it is likely that soils will remain wetter than the seasonal norm. This will lead to an early onset of the normal seasonal recovery of ground water levels in the autumn. This may be good news from a water resources perspective, but is likely to herald a longer winter flood season, which is bad news in many other respects.
“In many rivers, maximum flows have exceeded their previous highest for the summer by very wide margins. We are lacking more definitive flow figures at the moment but it is possible that flooding may be as extreme as the 1947 flood that was caused by snow melt over frozen ground, which was the largest flooding event in southern Britain in over 100 years.”
Professor Ian Cluckie, Professor of Hydrology and Water Management at the University of Bristol and a Fellow of the Royal Academy of Engineering, said:
“The actual storm on Friday was brilliantly forecast by the Met Office but the problem is that it was a text-book case of river basin flooding. The storm started at the mouth of the river catchment and moved very slowly up-catchment. This is rare but not unknown. However, the lower reaches of the Severn were still recovering from the June storms so they had no storage capacity and filled very quickly — the river Avon suffered the same effects. Tewkesbury is at the confluence of the two rivers and has taken the brunt of the flood.
“So far the flood does not reflect the run-off from the Welsh mountains. This is expected to arrive in the next 24-36 hours and the water levels will probably rise again. If it doesn’t rain today at least the lower flood might drain away a little but there are also high tides today, unfortunately. These are also causing concern for the Thames as there is only a short window at low tide for the flood water to drain away.
“The June floods were a 1 in 200 year event. With this one coming so soon after, we are perilously close to the 1947 flood situation where the entire country was affected.
“The Environment Agency failed the get the flood barriers up in time, despite the forecasts; this is a disgrace. The flood waters could take a week to recede, and low-lying areas will have to be pumped out.
“We need to learn to deal with floods in the future. 10 per cent of UK housing is on flood plains but this is quite low compared to some countries – it is 70 per cent in Japan and 100 per cent in the Netherlands. We need better flood defences, given our current concerns about the impact of climate change on floods.”
Professor David Butler, University of Exeter, said:
“We know from our rainfall records and previous flooding events that every so often we do get extreme events that cause extensive flooding. Not unsurprisingly, this flooding happens in flood plains, which is of course prime development land. Most of our major cities are built on floodplains. Exactly when floods will occur and of what magnitude is not predictable, unfortunately. The global climate models indicate a future for the UK with drier summers and wetter winters, but storm events in the summer are predicted to be more frequent and more intense. So it may well be the case that we will have to learn to live with more flooding.”
Dr Tim Evans, consultant and chairman of CIWEM Wastewater Management Panel, said:
“This is an extreme weather event, and as such it will happen from time to time. It may be due to climate change. It is consistent with the consensus prediction for the effect of climate change in the UK, which is that what we now think of as extreme events will occur more often than in the past and that the extremes will get more extreme.
“We could improve the situation for the future by coordinating road drainage, surface waters, sanitary drainage and flood protection. Currently these are the separate responsibilities of local councils, the Environment Agency and water companies. This could include designating selected roads as flood channels and also working to separating surface and sanitary drainage so that when there is flooding, the adverse impact is minimised.
“In addition, we can contribute individually by considering drainage when we are deciding to pave a front garden, build a patio or put up an extension. These can all contribute run-off water. If the water could be made to infiltrate or if the run-off could be modulated then this would represent less of a problem.
“However, there will always be some occasions when the power of nature is more than we can cope with, but there are things we can do to cope with more extremes better.
“European environmental policy has been, and continues to be, focussed on ecological and chemical quality. We have more species of fish etc. in our rivers than at any time since the start of the industrial revolution, which is marvellous but European policy is driving more expenditure for even cleaner waters. Some of the chemical standards are more stringent than toxicology requires. All this costs money, energy and climate change emissions. Maybe in the future policy should be more proportionate, consider all the impacts and re-balance the spending towards infrastructure.”
Bob Sargent, CIWEM President, said:
“We have learned from recent flooding events that barriers and walls are not always effective and can in fact create a build up of water and rapid flooding which may even cause more damage. The reality is that you cannot design flooding out of urban spaces. Therefore, as the Government gears up to build 3 million new homes, it is vital that planners and developers move away from trying to resist seasonal influxes of water and move towards designing for flooding and absorbing excess water safely. This can be aided by taking some simple steps such as: incorporating green roofs, creating recreational areas within cities, and providing storage areas such as wetland habitats and water bodies upstream. In fact, planners could take this as a golden opportunity to make properties safer but also improve our environment with green spaces and create richer habitats for wildlife.
“A further problem that must be addressed is our fragmented approach to drainage. Local authorities, water companies, highway authorities and the Environment Agency all have separate roles with nobody having an overview for the whole catchment. Many local authority departments are under-resourced to carry out their drainage role adequately, and their boundaries do not often co-incide with catchments. With increased development and climate change making extreme events more likely we now need strong integrated drainage authorities who can take an overview and co-ordinate a new approach to living with flooding.”
Professor Bob Spicer, The Open University, said:
“Basically the events we have seen over the past few weeks, and in particular the serious floods at the end of June and over the last few days, are typical of the kinds of things we can expect more of in the future. A warmer world leads to more evaporation but also more rainfall and the storm systems associated with a warmer atmosphere produce heavy downpours.
“Flooding is made worst by several factors, including confining river channels by urban development instead of letting them naturally expand over the floodplain (if the retaining walls don’t fail this just moves the problem further downstream), and also concreting over naturally absorbent land surfaces so more water runs off into sewers and river courses.”
A spokesperson from the Chartered Institution of Water and Environmental Management, said:
“This is an extreme flood event. Flooding can not be prevented; we can only ever reduce the risk.
Flooding must be taken into account when making planning decisions.
We welcome the increase in funding for flood and coastal defence recently announced by the Government, but CIWEM hopes that the priority scoring for schemes takes the social and health impact of flooding on people fully into account.”
Professor David Stephenson, Met Office Chair at the University of Exeter, said:
“There’s no obvious culprit for the unusually long wet spell we’ve been experiencing this summer and so there’s no reason to believe it will persist for the rest of the summer. We could revert to more normal summer weather at any time.”
Professor Bill McGuire, director of Benfield UCL Hazard Research Centre, said:
“While it still holds true that we can never attribute a particular weather event to climate change, the current devastating floods form part of an expected trend that will see the country facing more frequent and bigger floods in coming decades. We need to be aware that anywhere on a flood plain could flood at any time – winter or summer – and take remedial action now. Any plans to build new properties on flood plains given current climate change predictions and recent events, would be irresponsible in the extreme.”
Nick Reeves, executive director of the Chartered Institution of Water and Environmental Management, said:
“Extreme events such as we have seen in recent weeks herald the spectre of climate change and it would be irresponsible to imagine that they won’t become more frequent. Before the Government presses ahead with plans for new housing on the huge scale suggested, it must ensure that we have the infrastructure in place to deal with the worst of climate change.
“Scratch the surface of flooding related problems and it comes back to the way we live our lives. Unless there is action on population and consumption, and unless we realise that building thousands of new homes on land at risk of flooding is putting people’s lives at risk, then we are storing up problems for future generations that could de-stabilise towns and cities, and render the goal of sustainable communities unattainable. Lifestyle change must be one inevitable consequence of climate change if we are to avoid the kind of human misery we are now seeing.
“The Government must learn the lessons of these floods and avoid storing up problems for the future by concentrating on development on brown-field sites. They need to undertake a strategic land review as less than one percent of the population of Britain owns 70 percent of all land. The condition and status of much of this land is unknown and it may be that some of it could be released for housing.
“The Government must also put a stop to outmoded ‘predict and provide’ approaches to planning and do something about demand management.
“The Government must review its plans for development to ensure that new housing on land at risk of flooding is accompanied by investment in robust flood defence and an adequate drainage infrastructure that take into account climate change projections.”