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Beach work progressing well
30 April 2012
Work to regrade Scarborough’s South Bay beach, which will help
reduce the risk of severe flooding in Foreshore Road, will continue
this week (from 30 April).
The annual operation involves the redistribution of sand that
has been forced towards the back of the beach during the winter
months by wind and high tides.
Scarborough Borough Council Principal Coastal Officer, Stewart
“There is a tendency for sand to accumulate in front of the sea
wall at the north end of South Bay in the lee of the West Pier. In
winter this results in frequent wave uprush over the wall and
across the road, causing property damage and the need for regular
clean-up operations. Sand blocking drains and gullies restricts the
free drainage of floodwater which lengthens the duration of flood
incidents, prolonging the misery for those affected.
“When beach volumes reach a critical level in the northern
section, sand is excavated in the vicinity of the Foreshore and
then spread and graded in front of the sea wall that protects the
Spa approach road.
“In the absence of these beach management activities, beach
levels would accumulate to the point where waves would ‘ramp’
across the upper foreshore, overtop the seawall and cause even more
serious flooding in Foreshore Road than we experience now.”
Foreshore Road was laid out along the back of the beach in the
1870s, with the broad carriageway and promenade created behind a
small seawall. The consequence of a smaller seawall means the area
is prone to flooding during heavy sea conditions.
Beach management activities have been undertaken since the 1990s
in a bid to prevent the “beach ramping” effect. The recycling of
sand also has the effect of offsetting the slow erosion that is
perceived to have been occurring for some time towards the southern
end of the South Bay, although this benefit is only temporary as
the recycled sand will tend to move back towards the north of the
South Bay by natural processes or be drawn down the beach during
particular storm events.
Typically, the sand excavation is undertaken along approximately
300 metres of frontage directly in front of Foreshore Road. Levels
will be reduced to around 1.2 metres below the crest of the seawall
directly at its toe, falling to a zero metre reduction at a
distance of 25 metres from the seawall. These beach management
activities are usually undertaken annually in April.
While typical wave and tide conditions tend to drive the
northwards transport of beach sand along the foreshore, storm
events tend to strip sand from much of the upper foreshore and
transport it seawards, where it either becomes deposited on the sea
bed or remains suspended in the water column and becomes
transported southwards by residual tidal currents. This typically
results in beach lowering at the toe of the seawalls during these
Excavation of the sand has the following advantages:-
- Reducing flood risk to properties on Foreshore Road
- Reducing the risk of wind-blown sand (which in turn would lead
to blockage of the highway drainage system and increased flood
- Reducing the volume of sand deposited on the bar offshore from
Scarborough Harbour which could cause impediment to navigation of
vessels (including the lifeboat) and which in turn, reduces the
potential for sand transport along the bar into the harbour where
it becomes deposited and requires dredging
- The recycling of the excavated sand to enable its placement,
spreading and grading in front of the Spa approach Road has the
advantage of temporarily improving beach levels in an area where
the beach is generally lower in level and more prone to
Beach management activities of this nature will continue in the
South Bay when studies show there is the need.