Birling Gap is a small remote bay east of Beachy Head in East Sussex. The beach is
approximately 300 metres (m) wide with a gentle slope. It is situated right below
the backdrop of the Seven Sisters chalk cliffs. The beach is predominantly shingle,
but shallow sandflats and rocks from the chalk cliff become exposed with the receding
tide.
In 1990 a long sea outfall was commissioned for the Newhaven and Seaford discharges.
The outfall is located offshore approximately ten kilometres west of the bathing water.
Flows from Lewes sewage treatment works were transferred to the long sea outfall prior
to the 2000 bathing season. In 2001, Newhaven sewage treatment works was upgraded.
Birling Gap bathing water was only designated in 1998.
For the three year (2021-2023) assessment period where data is available, seaweed
(macroalgae) was not assessed as being sufficient to be objectionable, but was observed
as being present on 66% of visits. The shore can become covered with seaweed, depending
on tides and the weather. Groynes, rocks and other fixed objects may have a covering
of seaweed which can be slippery.
Modern sewerage systems have two separate systems, one takes foul sewage to sewage
treatment, the other takes rainwater runoff through surface water drains to rivers,
lakes and the sea. Misconnections occur when waste water pipes are plumbed into surface
water drains instead of the foul water sewerage system. This can give rise to pollution
when the waste water is discharged directly to the environment through the surface
water drain. For example, a washing machine or toilet may be incorrectly plumbed so
that it discharges to the surface drain rather than the foul sewage drain.
For the three year (2021-2023) assessment period where data is available, phytoplankton
(microscopic algae) was not assessed as being sufficient to be objectionable, but
was observed as being present on 7% of visits. Microscopic algae (phytoplankton) increase
in number at certain times of the year. This process is known as a phytoplankton bloom.
Blooms of phytoplankton can result in the water appearing discoloured or a foam forming
on the water.
The risks to human health from contact, ingestion or inhalation with marine algae
that currently occur in UK coastal waters are considered to be low. However, some
individuals may be more sensitive and display some reactions.
A common marine algae found in UK coastal waters is Phaeocystis, which is often mistaken
for sewage as it forms foam and a brown scum, but it is non-toxic.
There are no active pollution risk forecasts made at this bathing water. However any
bathing water has the potential to be affected by a pollution incident and if this
occurs a pollution risk warning with associated advice against bathing will be issued
on this website.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Birling Gap
for the three year (2021-2023) assessment period where data is available, sewage debris
was not noted at this site. Litter was assessed as being sufficient to be objectionable
for 2% of visits, with 12% of visits noting the presence of litter. Tarry residue
was not noted at this site.
The natural drainage (hydrological) catchment surrounding the bathing water is approximately
1600 hectares. The catchment includes hilly chalk downlands and the villages of Eastdean
and Friston. The majority of the land in the catchment is rural with some livestock
and a small amount of woodland. Since the chalk is porous, surface water will drain
through it until it hits deeper layers of rock. The catchment map is based on the
surface profile and therefore hypothetical. The direction of the runoff depends on
deeper layers of rock.
Seaweed (macroalgae) and phytoplankton (microscopic algae) are a natural part of the
marine and freshwater environment. Below we note whether these have been recorded
in quantities sufficient to be a nuisance.
The majority of sewers in England are “combined sewers” and carry both sewage and
surface water from roofs and drains. A storm overflow operates during heavy rainfall
when the sewerage system becomes overwhelmed by the amount of surface water. The overflow
prevents sewage from backing up pipes and flooding properties and gardens. An emergency
overflow will only operate infrequently, for example due to pump failure or blockage
in the sewerage system.
Heavy rain falling on pavements and roads often flows into surface water drains or
highway drains, ending up in local rivers and ultimately the sea. The quality of bathing
water may be adversely affected as a result of such events.
It is the Environment Agency role to drive improvement of water quality at bathing
waters that are at risk of failing higher standards. It is natural for water to run
off the land to the sea. Water quality at a bathing water is dependent upon the type
and area of land (the catchment) draining to the water and the activities undertaken
in that catchment.