Select Committee on Environment, Food and Rural Affairs Minutes of Evidence


Examination of Witnesses (Questions 160 - 169)

WEDNESDAY 7 NOVEMBER 2007

PROFESSOR EDMUND PENNING-ROWSELL AND PROFESSOR HOWARD WHEATER

  Q160  Mr Drew: If we can look at this issue of the maintenance of existing flood defences, if you look at some of the evidence that has come our way—which I presume we have published and so is in the public domain—there are a lot of people who feel very strongly about some of the maintenance gaps. We have had this popular debate, for example, should we be dredging the rivers? I am pretty sure that this is not helpful in terms of anything other than good maintenance, but it would not to my mind prevent flooding. I just wondered where both of you stand on this issue about the degree to which the Environment Agency, and indeed the water companies, have been negligent in some of the maintenance programmes that they have operated, and is this something that in a sense we should be really hot on in terms of our report?

  Professor Wheater: I do not really have personal expertise to give you a comment on that. I think there are people who could help you, so there is Professor Jim Hall from Newcastle who has done a lot of work in this area, and a team at Hydraulics Research at Wallingford, including Dr Paul Sayers, but I have just not been involved with the maintenance side of the business.

  Professor Penning-Rowsell: The same.

  Chairman: It is no use asking these two!

  Q161  Mr Drew: Could I have a quick rejoinder there. You have given us some pointers as to who we should go to, but looking at the more strategic direction, you said that you are not expert but, again, if I was a climate change denier, which I am not, I think I could come up with a pretty good set of opinions on how this could all be sorted out in due course of time, we do not need all this big map stuff, we can deal with it on a pretty micro level, and just a few thousand years will make all the difference. I see Professor Penning-Rowsell has been roused!

  Professor Penning-Rowsell: I think you have to remember that in the 2007 events very few flood defences failed. They may have been overtopped—

  Q162  Mr Drew: --- Hilary Benn always reminded us on that.

  Professor Penning-Rowsell: I think that is a very important consideration and poor maintenance, if it were really poor, would show itself as failure; it would not show itself as over-topping because every flood defence has a finite standard and may be over-topped, particularly when you get ten centimetres of rain in 24 hours. If you are to criticise maintenance you would have to show that there were widespread failures and I do not think you can demonstrate that.

  Q163  Chairman: Do I assume that perhaps the probing of you gentlemen about changes in farming practice and flooding may also be slightly outwith your knowledge?

  Professor Penning-Rowsell: No, he knows lots about that!

  Chairman: Roger, you are on!

  Q164  Mr Williams: In terms of land management there are two ways you could approach it: change your land management to prevent run-off; or dedicate land for taking water that could flood other areas. Are both those approaches being investigated?

  Professor Wheater: Yes, I think there are some important issues in the area of agricultural land management and river flood plain management, and technically they are quite challenging. I think it is clear that there has been a very large amount of intensification in the rural agricultural sector and there is quite a lot of anecdotal evidence that that has given rise to increases in local flooding, but there is no evidence of what the impacts might be at the larger scale of the Severn River, for example. At the moment I lead a research programme which is working with a consortium of farmers in Wales to consider impacts of intensification on the way in which run-off is produced and what that might do for flood risk. Just to give you some examples, over the period from the 1970s to the 1990s the number of grazing animals—sheep mostly—went up by a factor of six and in some cases the weight doubled, and so the farmers themselves were very concerned about issues of compaction and the fact that they perceived that run-off was occurring more rapidly and streams were having more flashy response and a higher flood response. Interestingly what the farmers have been doing is to reinstate some of the features they were paid to take out—and that is things like hedges and shelter belts—and what has been observed as a result of that is a significant improvement in the structure of the soil and hence its ability to absorb water. We are carrying out trials at the moment with different land use, different grazing densities, different land use in terms of tree planting, and those are fairly long term, and we have also developed models which have been built around the data to come up with predictions of effects, and you can clearly see that if you put tree shelter belts, improve the soil structure and put them in the right places, you can improve flood risk. The level of improvement is still very much open to debate, particularly as you move up scale, and of course the effects are likely to be much more evident for the frequent events than for the really big events because with the really big event everything that is going to run off is going to run off, and what you do on the land has less effect, but our work indicates that you might reduce flood risk by the order of a few tens of per cent. There is a certain amount of work that has been done at the larger catchment scale, up to 100 square km, simply by simulation modelling and the conclusions there are that under an extreme range of different land uses you might see a ten or 20 per cent change in flood risk. For the rarer flood events—50 or 100 years events—it might be a three to ten per cent effect. That is in terms of run-off production. I think there is certainly scope for mitigating flood risk by appropriate changes to agricultural practice, and those are the sorts of changes that are consistent with what you would need to help the problem of nutrients and pollution from fertilisers and so on. Thus there is a need for an integration of land management and water management; I think that is clear. The problem of transmission is very interesting because clearly the history has been that flood plains have been progressively disconnected from the rivers for urban protection, and also to increase agricultural productivity, and there is a lot of interest in reconnecting them and using them for retarding the floods and stalling the floods. There are some examples of flood mitigation schemes which use constructed flood plain storage, but there is a lot of interest, I think, within the agricultural sector in the return of some farmland to increasingly active use for flood mitigation, and that can have quite a significant and beneficial effect.

  Q165  Chairman: I just want to conclude to go back Professor Penning-Rowsell to some critique you were making about the scoring system for prioritising future flood expenditure. The Chartered Institution of Water and Environmental Management have advised the Committee that this activity should be reviewed because they say that the rules of the system "allow for almost no consideration of scheme components that do not directly contribute to flood alleviation", and they would like to see what they describe as a more holistic approach to be adopted in terms of the scheme justification criteria.[5] Taking that into account, are we too narrow and too restrictive and, in contrast, are there any other types of flood prevention prioritisation processes that you have seen outwith of the United Kingdom that we ought to be aware of and ought to look at?

  Professor Penning-Rowsell: The answer is we have been too narrow but there is a change being made now away from a narrow economic appraisal of flood and coastal erosion risk management investment towards a series of outcome measures which are broader in scope, and Defra has been consulting and the Agency has been consulting over the last, I guess, 12 months on that new system, which would move away from a simple economic analysis to one based on a number of metrics including social, environmental and economic considerations. In that respect, I think we probably are ahead of practice in many countries which are only just catching up with our rather narrow approach that we are now rejecting, if you see what I mean. So if you look at countries across Europe the investment criteria has become rather narrow in its focus on economic analysis whereas we are moving in the other direction. The effects of that other direction in the UK will not be felt for some time because of course the investment programme that the Environment Agency has stretches ahead for many, many years—several years anyway—so you will not see a change immediately, but the philosophy has been changing quite radically since Making Space for Water was introduced and Making Space for Water made it clear that a broadening of the appraisal criteria was needed and it set out some ideas which have now been taken forward by Defra.

  Q166  Chairman: So effectively this broadening process will not have any impact until after the current Comprehensive Spending Review?

  Professor Penning-Rowsell: I do not know what the timescale of the Comprehensive Spending Review is.

  Q167  Chairman: Three years.

  Professor Penning-Rowsell: Three years from now?

  Q168  Chairman: Yes.

  Professor Penning-Rowsell: I would say that the effect of the outcome measures will probably be felt towards the back end of that period but not before because otherwise you simply waste the effort that has been put into appraising the projects that already are in the queue and, as I said before, the queue is congested and therefore there are undoubtedly schemes that should be done. Whether a slightly different and broader appraisal system would bring other schemes in and throw some out, I am not very clear about, but a change is afoot, and I think a change for the good.

  Chairman: That is a good note on which to end.

  Lynne Jones: Could I ask one last question?

  Chairman: As long as it is a tiny postscript.

  Q169  Lynne Jones: We were discussing earlier the inadequacy of investment in this area. Is there any scope for UK plc, as it were, to benefit in this area—you said we were ahead of game—in terms of benefits to the economy for having this expertise and offering it in other countries?

  Professor Wheater: I think that we have a very strong engineering sector in the UK with a huge international portfolio and these techniques and the skills will be marketable and used worldwide, particularly I think within Europe under the new Floods Directive that will encourage much more of an integrated assessment, and I think there are opportunities there.

  Chairman: Jolly good. Thank you both very much indeed both for your oral evidence and, as I said at the outset, for your written evidence. There may be one or two points upon which we would like to quiz you further and I hope you will not mind if we decide in the future to write to you. Thank you very much indeed for giving us the benefit of your knowledge and perspective; it has been genuinely very useful.






5   Ev 481, para 23 Back


 
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