17 May 2000

Dear Mr Morgan

AGGREGATE DREDGING

RE: GOVERNMENT VIEW (NASH BANK)i 17/9/99

RE· REOUEST FOR EXTENDED TERMS (HELWICK BANK)i 19/11/99

I have had recent cause to revisit the above in the preparation of reports. I would request a response from NAW officials; taking advice from external consultants as necessary, on aspects we have previously raised. But now raised in more detail. You will recall that I am a member of the Welsh Office `Bristol Channel Marine Aggregates Steering Group' and therefore have seen many relevant reports.
A. Local drawdown of sand
1. Firstly there is a need to obtain definitive figures of the size (volume) of both Nash and Helwick banks, using standardised and accepted technique, and for this to be undertaken on a regular (e.g. at least annual) basis. Consultant's reports show various figures particularly for the Helwick. There is a need to standardise measurement to different heights - Chart Datum. e.g. To -15m, -20m, -35m.
2. There seems to be value in stipulating the figures for the amount of sand historically removed by dredging in relation to the total volume of each bank. Whilst we have taken a quick look at the figures (enclosed), Consultants could do so more accurately. Figures for future projected removal could also be looked at in the same way.
3. Consultants are all of the same view that the Helwick Bank has not yet decreased in size over the years. The situation on the Nash is less certain, but indications are that any change could be seasonal or annual, but that even though the bank shape broadly changes the overall volume has not yet significantly decreased.
4. Therefore, (and the Consultants all seem to agree) there exists a feed of sand to each bank from the surrounding area, the nature of which is bank specific.
5. My main question to experts is this:
Can they give absolute assurances that there is no danger of drawdown of local beaches (especially Porthcawl and Port Eynon/Oxwich/Mewslade specifically)? Over what wider area may the effects of local drawdown (agreed A.4 above) be extended?
6. It seems clear to many that the area surrounding the Nash has a thinner layer of surface sand than hitherto. Models which seem to explain the general mair.tenance of bank volume despite significant sand dredging removal seem to concur with tha view.
Hydraulics Research in their Auaust i9g`/ (E~:3~46) report omthe Helwick (Para 8 Sec 4.3) also make an ambiguous statem~~3.~ re Port Eynon beach and the eastern Helwick. which suggests to me that there may be v :Aider implications of local drawdown as the banks, in a dynamic hy~rographical sitaation, seek to maintain volume in the face of sand extraction.

Please could you establish a view from Consultants and receive their assurances in writing before any further extensions to dredging are given by the Assembly. .
B. Larger scale sand movement
l. Various consultants indicate a large scale, long term residual movement of sand from east to west in order to form the mid charlnel large sand wave structure so referred.
2. If this process continued then this bank structure would move ever seaward. It apparently does not and is stable. Accordingly there must exist some form of balancing west to east movement.
3. ABP Research Consultants have sought to address this through sediment particle movement analysis studies off Govan Head via fluorescerit labelling.
Please note that in our view this study did not address storm movements originally intended and covers only "summer storms south westerly force 5 or 6". What of storm force 10 winds?
I believe that large storm events have the capacity to remove large volumes of sediment and to great depths (witness the Milford Haven dump site studies).
To what extent can the Consultants quantify this movement and indicate the extent this would balance out any residual longer term gross westerly movements of sand so referred at B.1 above? C. Within our understanding (or lack of understanding) of the quantification of the physical processes
involved in A and B above, to what extent can various Consultants give a categorical assurance that:1. The changes being experienced to sand levels on beaches as far afield as Porthcawl and Tenby are not a result of aggregate dredging?
2. There is no relationship between the historically large quantities of sand removed by dredging on the Nash and Gower beaches/Helwick Bank?
I can recall no longer term tracer studies based, for example, on the Nash. However, other studies e.g. on the movement of sands dumped on the Swansea Bay dumpsite do show significant movement in storm conditions albeit inward to Swansea Bay and not laterally.
D. Ecological aspects
You will recall that my Committee's previous submissions have centred upon the potential impacts of dredging on ecological aspects.
We still maintain the stance that detrimental changes have taken place on the Nash and we would not wish to see transfer of dredging effort to the Helwick.
Committee has previously commented and critically appraised the Environmental impact statement/assessment work on the Helwick. Indeed it commissioned an independent report on that work.
Please be aware that we have not received an adequate response (even a response) to these concerns and our independent experts submission of December 1997 appears to have been ignored.
Before I am personally labelled as `anti' all dredging aspects, please be aware that it is my personal view that the changes we are experiencing on local beaches are part of a longer term natural sequence, independent of dredging, and in due course sands will return. However, that is only my personal view, and I am not an oceanographer / coastal geologist which is why I raise the above questions of such experts.
The biological/ecological aspects do remain a serious concern of mine, and are areas in which I have some experience.
I trust that you will, in due c`.:urse, be able to respond in full to this letter, and provide the necessary reassurances.

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