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Walney Island Conservation Areas:

Walney Island Geological Conservation Review (GCR BLOCK CST-GME-EG)

The Walney Island Geological Conservation Review took place in 2003 and was based around grid reference SD170730 - the northermost end of Walney Island. The review was of the overall coastal geomorphology of Great Britain, and a copy of the relevant volume can be purchased for around 80 from the NHBS Environment Bookstore as part of the Coastal Geomorphology of Great Britain (2003) - volume 28 - by V.J. May & J.D. Hansom.

The review was conducted by The Joint Nature Conservation Committee. The JNCC (as it is more ofen called) is the UK Government's wildlife adviser, undertaking national and international conservation work on behalf of the three country nature conservation agencies English Nature, Scottish Natural Heritage and the Countryside Council for Wales. The following links are to just some of the documents on the JNCC web site which are relevant to the Walney GRC block.

The following extract comes from the JNCC's report into various sites of special scientific interest, throughout the whole of the UK. The full report can be found here on the JNCC web site.

A3.4.1 Walney Island, Cumbria

The two sites at Walney Island represent the distal features of a barrier island. There are few examples of this type of feature in Britain and Walney Island is exceptional in being the product of erosion and reworking of glacial sediments, rather than coastal deposition. The spits at Walney Island are important in several respects:

1) They represent the distal features of the offshore bar and occur in a macrotidal location;

2) They differ in both form and sediments - North End Haws is fed by sandy sediments in the intertidal zone and has small dunes on its surface, whereas South End Haws comprises mainly shingle with limited dune development;

3) They are associated with scars (boulder- and cobble-dominated areas of the intertidal zone) which are a characteristic form of this coast. The sites at Walney are important both in their own right and for comparative studies with other barrier island-type features.

The Southern Haws Point Spit is fed by a southerly drift of sediment derived from the erosion of till cliffs that form most of the western side of Walney Island. Sediments are dominantly gravelly. Beyond the distal end of the spit, strong tidal currents have developed a large channel and are capable of advecting away finer the components of the sediment (JNCC, in prep.).

The Northern End Haws Spit is dominated by much sandier sediments derived from a northerly drift from the eroding till cliffs of western Walney Island. The distal end of the spit is broad and is marked by dunes resting on a shingle base adjacent to a wide sandy intertidal area (JNCC, in prep.).

Accretion on the southern spit results primarily from sediment transport from the seabed (Phillips, 1969) thus changes in offshore bathymetry and removal of sediment through aggregate extraction will have consequences for spit development (JNCC, in prep.). Transfer from the seabed is controlled by the tidal stream assisted by the prevailing westerly waves.

Contrasting ebb and flood circulation patterns are encountered in Morecambe Bay, but both act to transport sediment into intertidal areas where it can be delivered to the southern spit by longshore drift (Phillips, 1969). Accretion of the northern spit is, however, poorly understood with a northerly drift counter to the dominant southerly longshore sediment transfer occurring (Steers, 1946).

The relationship between the northern spit and the adjacent dune complex at Sandscale Haws and the extensive sand flats of Duddon Sands is also poorly understood and requires further research (JNCC, in prep.). There is a possible case for GCR boundary extension in association with the southern spit on Walney Island given its proven dependence upon offshore dynamics and sediment supply, however further research is required to assess the full dependency of the site on these offshore processes and the degree to which perturbation of those dynamics may result in site degradation. The case for boundary extension is hindered in the north by a marked scarcity of data. It is considered here, therefore, that further detailed oceanographic research, numerical modelling, and potential threat analysis is needed before an accurate assessment of the desirability of boundary extension can be fully undertaken.

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