Stoke Lake Flood Defences

Stoke Lake Flood Defences

Last week at Full Council, Conservatives voted to invest £3.8 million in flood defences, protecting us from coastal erosion.  This is a matter of huge importance to me and Councillor Philip Raffaelli, your ward Councillors in Anglesey, as our Ward includes Stoke Lake.

114 properties in Anglesey and Alverstoke are currently at risk of a 1 in 100 year flood event, and this is expected to rise to 142 properties by 2060.  The flood defence scheme will cover approximately 120 metres of coastal frontage at the western end of Stoke Lake.

The proposal and my views on it

  • The existing weir, built in 1972, would have to be demolished as “The weir butts up against the existing railway bridge supports, with the exact nature of the joint between the two structures unknown. The construction makeup of the railway bridge foundations and the weir foundations are also unknown.”
  • To enable safe access to demolish and replace the existing weir, a coffer dam would need to be constructed on the eastern flank of the railway bridge to allow Stoke Lake to be drained completely for the duration of the demolition and construction works. Given the proximity of the weir to the bridge, there is also a high risk that substantial temporary works may be required to support sections of the bridge during demolition and construction.
  • The Jackie Spencer Bridge option would include the demolition and re-build of the weir, with an additional gate system on top. The methodology required to construct the weir and gates, as explained above, would encroach and impact on Little Anglesey Lake habitats
  • It was more expensive than the “causeway scheme".

Having spoken and sought the views of local residents, I believe there is an alternative, at lower cost, to the proposed wall on the causeway at the western end of Stoke Lake.  

Here's my alternative

•     Leave the existing weir as it is and therefore there is no need to drain Stoke Lake or build a coffer dam.  There are no habitat concerns as the lake does not deed to be drained.

•     Build a new wall under the eastern side of Jackie Spencer Bridge. The length of this wall would be approx. 7m at the base up to 19m at the top.

•     Within this wall have a sluice gate which will be open until such time as the 1 in 100 flood is forecast.

•      As the tide will flow freely through this wall/sluice gate I do not see why the foundations would have to be excessively deep in the shingle at it base.

•     The water at low tide drains completely, which happens twice a day at the creek, therefore the construction could be started without building a coffer dam. Remember the Victorians built the 3 Spithead forts without constructing a coffer dam. If the Victorians could do it surely we in the 21st century can do it.

This wall only needs to hold back the flood tide for no more than a couple of hours at the 1 in 100 year flood rather than be a 100% water tight structure.

The advantages of my “alternative Jackie Spencer Bridge” are the following:

• It will protect an additional 30 properties, on the north and south sides of Stoke Lake including Brookfield Retirement Home and 8 properties in St Mark’s Road.   

• The Causeway is a medieval structure, which is shown at least on a map dated 1580; therefore we are trying to get it listed. It would be best not to put a modern wall on top of it.

• I believe that the “causeway scheme” would only protect for 40 years whereas the “Jackie Spencer scheme” would be for 100 years.

The cost advantages have to be worked out in detail but the following should be considered:

With Gosport’s strong armed forces heritage, a great suggestion to reduce the cost further would be to see if the Royal Engineers would consider help in using this wall as a training exercise for their own people.

Please get in touch and give me your views:

Councillor Alan Scard, Anglesey Ward

Tel. 023 9252 3095