Botany Bay, between Margate and Broadstairs in Kent has over a kilometre of sandy
beach above an extensive wave-cut rock platform, backed by white chalk cliffs.
Margate storm and emergency overflows are 1 km to the northwest of the bathing water
(the storm overflow is offshore, and the emergency overflow is on the shoreline).
The Broadstairs North Foreland storm overflow is offshore 3.5 km to the east. There
is also a short sea overflow offshore 750 m to the east. These outfalls are designed
to ensure the bathing water is protected.
Prior to March 2007 there was a screened crude sewage discharge from the North Foreland
3.5 km long sea outfall. There was also a storm discharge from a 400 metres outfall
from the same pumping station. In March 2007 the North Foreland long sea outfall became
a high frequency storm overflow and the short outfall was converted to an emergency
outfall. Sewage flows were diverted to full treatment (including UV disinfection)
at Weatherlees sewage treatment works before being discharged via the Margate long
sea outfall 2 km north of Botany Bay.
A partnership group between the Environment Agency, Thanet District Council, Kent
County Council and Southern Water has been formed. The aim of the partnership is
to work together to better understand risks to bathing water quality and put measures
in place to make improvements.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae)
was not assessed as being sufficient to be objectionable, but was observed as being
present on 92% 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 four year (2020-2023) assessment period where data is available, phytoplankton
(microscopic algae) was assessed as being sufficient to be objectionable for 2% of
visits, with 5% of visits noting the presence of phytoplankton (microscopic algae).
Phytoplankton (microscopic algae) 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.
Weatherlees sewage treatment works discharges offshore via the Margate long sea outfall
2 km to the north of Botany Bay. This outfall is designed to protect bathing water
compliance.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Botany Bay,
Broadstairs for the four year (2020-2023) assessment period where data is available,
sewage debris was not noted at this site. Litter was not assessed as being sufficient
to be objectionable, but was observed as being present on 93% of visits. Tarry residue
was not noted at this site.
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.
