The bathing water is a resort beach on the south coast in West Sussex, backed by an
urban area with the town centre close by. The bathing water is predominantly a groyned,
shingle beach but with gently shelving sand exposed at low water. A promenade sits
above the beach with a pier and lido to the east.
Within the vicinity of the beach there are 4 surface water outfalls namely Sea View
Road, Heene Terrace West, Heene Terrace East and West Street. Reduced water quality
may persist in the area adjacent to the outfalls for some time after rainfall has
occurred. There are also 3 storm overflows over a km away to the west of the bathing
water. Discharges occur when heavy rainfall overwhelms the sewerage system but are
designed not to affect bathing water compliance. There are further surface water drains
over a km away to the east and west.
In 1996 sewage from the Worthing area was transferred to Worthing sewage treatment
works and received primary treatment before being discharged via a long sea outfall
5km out from the shore. In 2002 Worthing sewage treatment works was upgraded and the
effluent is treated before being discharged through the long sea outfall. Currently,
Southern Water are involved in a programme of investigation and modelling to try to
quantify, and identify causes of, contamination to the surface water system that drains
rainfall to the beach in Worthing. The final aim of the project is to identify solutions
to eliminate or reduce these contamination problems.
Over the last several years, the Environment Agency have investigated the level of
contamination from the surface water system that drains to the beach. The investigations
suggest the contamination arises from diffuse urban pollution.
For the four year (2015-2018) assessment period where data is available, seaweed (macroalgae)
was assessed as being sufficient to be objectionable for 1% of visits, with 53% of
visits noting the presence of seaweed (macroalgae). The bathing water 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 (2015-2018) 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 12% 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.
This bathing water is subject to short term pollution. Short term pollution is caused
when heavy rainfall or high tides wash faecal material into the sea from livestock,
sewage and urban drainage via rivers and streams. At this site the risk of encountering
reduced water quality increases after rainfall and typically returns to normal after
1-3 days. The Environment Agency makes daily pollution risk forecasts based on rainfall
and tidal patterns and will issue a pollution risk warning if high tides or heavy
rainfall occurs to enable bathers to avoid periods of increased risk.
The Environment Agency works to reduce the sources of this pollution through pollution
prevention measures, work with agriculture and water companies.
5 warnings advising against swimming due to an increase risk of short term pollution
were issued in 2018 for Worthing bathing water. These warnings were issued because
of the effects of heavy rain on the water quality.
There is a high standard of treatment at the sewage treatment works discharge 5 km
from the shore of this bathing water which is designed to protect bathing water quality.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Worthing for
the four year (2015-2018) 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 22% of visits. Tarry residue was not noted at
this site.
There is a discharge from a pharmaceutical plant in Worthing that enters the sea via
a long pipeline 4 km from the bathing water. This effluent it treated and acidity
regulated (a process which disinfects the effluent) so it presents a negligible risk
to bathing water quality. The timing of the discharge is such that the effluent will
be taken away from the bathing water.
The beach is situated in a flat-lying coastal plain without a significant river network
in the immediate vicinity of the bathing water. The natural drainage (hydrological)
catchment surrounding the bathing water is approximately 120 hectares. The catchment
is urban and only extends to the centre of Worthing after which the watershed takes
rainfall inland. Rainfall is drained from the town by a surface water drainage network
that discharge to the beach between the high and low water marks via numerous outfalls.
To the east of Worthing there is a stream that is drained via an outfall some 3km
distant and another stream is 5km to the West.
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.