South West Hayling Island Beach Management Study
The South West Hayling Island Beach Management Study is a piece
of work currently being undertaken within the Coastal
Engineering Team. The Study is utilising existing survey data,
collected by Havant Borough Council officers as part of the
Southeast Regional Coastal Monitoring Programme, and new monitoring
techniques (beach sediment tracer study) to help improve
the understanding of this dynamic stretch of coastline.
Study Objective
The primary objective of the Study is to develop a sustainable
framework for managing coastal risk, predominantly erosion, around
South West Hayling. This framework is designed to inform and
enhance the coastal management capabilities of Havant Borough
Council around the Hayling open coast.
Photograph showing location of study area,
South West Hayling
Five technical objectives have been identified as key to
achieving a sustainable framework:
- To align current beach management practice around the entire
Hayling open coast;
- To identify beneficial practices for the co-management of the
study area and the Eastoke frontage;
- To address the future management of sea defence structures in
line with the current shoreline management policy;
- To provide solutions which are adaptable to sea level rise and
climate change;
- To provide amenity value.
The key stages in the study are as follows:
- Review of historical data, published literature and
reports
- Review of coast defence assets
- Predict future beach evolution
- Analysis of flood and erosion risks
- Technical, Environmental & Economic Option
appraisal
- Comparison & selection of preferred
option
Background
The study area is comprised of a mixed sand and shingle beach
which has tended to grow in size over the last century. Behind the
active beach is a sequence of shingle ridges that constitute the
cuspate foreland of Sinah Warren and Gunner Point. Historically
charts show pulses of beach material moving up into the Langstone
entrance channel. Currently one such pulse has developed into a
small spit just south of the Ferry Boat Inn. A second pulse appears
to be forming at Gunner Point currently and starting to move
northwards past the Hayling Ferry Sailing Club.
Offshore is the extensive area of the East Winner sands. A
recent comparison of the Langstone ebb tidal delta bathymetry from
1972 to 2008 shows large-scale changes across the entrance bar and
the West Winner. The lowering bed levels may signify large scale
changes to the way material moves around the shoal, and a drop in
supply bypassing across the Langstone tidal inlet. Over the last
two years alone the East Winners western flank has moved east up to
25 metres, and the main ebb channel has widened accordingly.
Within the overall long-term growth along the study area there
have also been periods of erosion in certain key areas. West of the
Inn-on-the-Beach erosion was a serious concern from the 1940s up
until new defences were built in the 1970s. The interaction of
these structures and the flow of material altered the beach plan
form right up to the eastern extent of the study area. By the 1960s
the open beach east of the Inn-on-the-Beach had grown up to 60
metres forward of its post-war position. From the 1960s to the
1980s the situation stabilised with continued accretion around
Gunner Point and erosion just west of the Inn-on-the-Beach and
associated control structures.
South West Hayling MHW contour; 1832, 1946
& 2007
Flood and Erosion Risks
Coastal erosion is the main challenge for beach
management around this section of coastline, with key sites at
West Beach and up inside the Langstone harbour entrance. Flooding
due to high tides or wave overtopping via the open coast has a
negligible impact around the study area assessed as part of the
Study. The 'pulses' of material moving around Gunner Point
historically resulted in the near loss of access to the Hayling
Ferry Sailing Club, although defences exposed in the
1990s are currently buried beneath an ample supply of beach
material.
Sea defences protecting access to Hayling Ferry
Sailing Club, 1993
Sea defences buried along access to
Hayling Ferry Sailing Club, 2008
Coastal erosion is also an issue in front of the West Beach
sloping timber breastwork, and just west of this area, resulting in
wave overtopping on to the Hayling Golf Club training area over
recent winters. Lowering beach levels combined with the age of the
sloping timber breastwork have combined to increase the risk of
this structure suffering a significant structural failure, similar
to the events recorded in 1990.
Significant structural failure of West Beach
sloping timber breastwork, 1990
West Beach Sloping Timber Breastwork - Potential
Structural Failure
Structural inspections have identified that sections of the
structure are in a very poor condition, and are at a higher risk of
failure over the winter months. The Study will assess the impact
removing the structure will have on the surrounding coastline and
identify the preferred approach to minimise any adverse impacts.
The final recommendations are anticipated in summer 2012.
An interim policy has been adopted should the structure fail prior
to recommendations being produced. The council will continue to
carry out minor repairs to the structure until the Study
recommendations are produced. Should a significant failure occur
the structure will be made safe but not rebuilt. Making safe may
involve removing sections of the structure to protect surrounding
sections from further damage. The intention would be to leave the
structure in a stable state, reducing the chances of further
failures occurring.
Link to West Beach Potential Structural
Failure poster (354 KB, PDF)