Saturday 17 May 08 - 03:24
 

Marine Civils by David Foxwell

Short Term Solution Proposed for East Head

Agreement has been reached by all interested parties that short term action should be taken to repair a 90m long eroded section of sand dunes at the neck of East Head, a natural sand and shingle spit at the mouth of Chichester Harbour on the south coast of the UK, whose beaches are enjoyed by half a million people each year. This will be done by recycling approximately 8,000m 3of sand and shingle from the northern tip of East Head, back to its original source at the Hinge.

Erosion of the hinge at East Head could have adverse consequences for Chichester Harbour and the marine industry located there.
Erosion of the hinge at East Head could have adverse consequences for Chichester Harbour and the marine industry located there.

This short term measure will 'hold the line' pending the implementation of a sustainable and environmentally sound long term solution that will flow from the Coastal Defence Strategy for this sector of coastline.

The Strategy is due for public consultation this Spring.

The recharge of material at the Hinge will be placed both in front of and behind the existing rock berm. The material in front will act as a sacrificial barrier to delay the erosion of the existing dunes, while at the rear it is planned to erect simple sand breaks, plant marram grass and to install a walkway. This will provide safe access for walkers onto East Head and it might allow new dunes to become established on the Snowhill Creek side of the rock berm.

The scheme will cost in the order of £11,000 and will be jointly funded by the Chichester Harbour Conservancy and Chichester District Council.

Subject to prevailing weather conditions and the time it takes to implement the long term solution for East Head, there may be a requirement to repeat the recharge in the future. This short term measure will still require planning permission and it is estimated by Chichester District Council, who will be managing and undertaking the project, that work may not be able to start on site until mid-April.

At the end of last year, English Nature proposed an innovative solution to the erosion of part of East Head. The proposal of the Government's independent wildlife advisor involves placing up to 10,000m 3of sand and shingle behind the 'hinge' at East Head to create a robust but flexible link between the mainland and the Head. This sand and shingle would create a new wider beach that can absorb the power of future storms.

Chichester Harbour Site of Special Scientific Interest (SSSI) forms part of an internationally important nature conservation area - the Solent Maritime candidate Special Area of Conservation (cSAC).

Tim Collins, English Nature's Head of Coastal Conservation explained that by working with the forces of nature, rather than battling against them, the proposal would provide improved access to East Head, prevent a new channel forming at the hinge - and ensure the future of the special sand dunes and beaches within Chichester Harbour. Any solution must take account of the fact that East Head has always been on the move - and the most sustainable option is to use the natural coastal processes to help conserve this special area.

Currently there is a rock berm buried in the sand dunes at the hinge that is intended to prevent a new tidal channel forming.

The rock berm is damaging the natural development of the dunes and beaches of East Head.

It reduces the sand moving over the hinge to create a natural and sheltered beach behind it that would provide a crucial buffer to wave action, preventing a new channel forming at this point. If the rock berm is kept in place, sand will continue to be washed away, the spit will get narrower, eventually the berm will be undermined and a tidal channel might form at this point, which could affect navigation within the harbour.

Images for this article - click to enlarge

Erosion of the hinge at East Head could have adverse consequences for Chichester Harbour and the marine industry located there.

All images copyright © Mercator Media 2008

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