Seaton is at the mouth of the River Seaton on the south coast of Cornwall. It is a
remote sandy beach, approximately 550 metres wide, surrounded by cliffs and hills.
The River Seaton flows across the beach to the sea.
There is an emergency/storm overflow from the Seaton pumping station that discharges
into the sea approximately 260m southwest of the bathing water. The operation of the
overflow can lead to a temporary drop in bathing water quality.
The sewage treatment scheme for Seaton and Downderry, which provides secondary treatment
and ultraviolet (UV) disinfection, was completed by South West Water in early 1998.
The scheme included the removal of untreated discharges which were retained as combined
sewer overflows (CSO), and the construction of a sewage treatment works at Seaton.
Storm overflow event duration monitoring (EDM) was installed at Seaton pumping station
by December 2011, and at Church Square CSO, Scawns Hill CSO, and the Factory pumping
station by April 2015. UV disinfection was installed at Menheniot sewage treatment
works (STW) by April 2015, together with work to reduce the frequency of storm discharges
from the Menheniot CSO. Improvements to Seaton pumping station emergency/storm overflow
are due by March 2025.
Since 2010 the Environment Agency have carried out additional catchment monitoring
alongside routine bathing water monitoring. The Environment Agency are using a DNA
tracing technique that helps us identify whether sources of faecal pollution are animal
or human. This work has shown that water quality at Seaton can be impacted by both
human and animal sources during periods of wet weather.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae)
was assessed as being sufficient to be objectionable for 13% of visits, with 75% of
visits noting the presence of seaweed (macroalgae). The bathing water can become covered
with large amounts of seaweed, depending on tides and the weather. This bathing water
does not have a history of large amounts of seaweed, but that it can be noticeable
from time to time.
For the four year (2020-2023) assessment period where data is available, phytoplankton
(microscopic algae) was not noted at this site. Phytoplankton (microscopic algae)
naturally increase in number at certain times of the year. This process is known as
a phytoplankton bloom. This bathing water does not have a history of phytoplankton
blooms.
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 procedures. The Environment
Agency makes a daily pollution risk forecast at this site based on the effects of
rain, tide, wind and seasonality on bathing water quality. These factors affect the
levels of bacteria that get washed into the sea from livestock, sewage and urban drainage
via rivers and streams and how they disperse.
When these factors combine to make short term pollution likely we issue a pollution
risk warning on this website and the beach manager will display a sign advising against
bathing at the bathing water. After a short term pollution event, levels of bacteria
typically return to normal after a day or so but it's possible to have several warning
days in a row. Details of the work to reduce the sources of bacteria at this bathing
water are detailed in this profile.
In 2023 14 pollution risk warnings were issued for this bathing water.
All bathing waters have the potential to be affected by a pollution incident and if
this occurs a pollution risk warning will be issued with associated advice against
bathing on this website.
Streams and rivers are typically affected by human sewage, animal slurry and runoff
from roads. The River Seaton enters the sea at this beach. The Environment Agency
have monitored the river since 1986 and found that water quality is temporarily worse
during and after heavy rainfall.
The outfall from the Seaton STW discharges into the River Seaton approximately 1.7km
upstream of the bathing water. This discharge is disinfected and designed to protect
bathing water quality.
The outfall and storm overflow from Menheniot STW discharge to the River Seaton approximately
8.5km upstream of the bathing water. The operation of this works and its impact on
bathing waters was reviewed, and the treated effluent is now disinfected 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 Seaton (Cornwall)
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 49% of visits. Tarry residue was not noted at
this site.
During and after periods of heavy rainfall, runoff to the Seaton River from agricultural
land is greatly increased, and the quality of the bathing water can be reduced. We
have worked with local farmers and our partners in Catchment Sensitive Farming for
advice and possible grant aid for improvements.
A number of grants were awarded in the locality and improvements completed, including
fencing livestock out of streams, covering yards and stores to reduce the amount of
dirty water produced, concreting yards and tracks.
There are homes in the village of Hessenford which have private sewage treatment arrangements
and may be contributing to poor water quality in the River Seaton. South West Water
are currently working on a scheme to encompass 34 of these properties into their network.
The catchment surrounding Seaton is approximately 5,600 hectares. The River Seaton
rises on Bodmin Moor and flows through the village of Hessenford, before entering
the sea at Seaton. The total length of the main river is approximately 18 kilometres
(km) (61km including the major tributaries). The steep narrow valley in the upper
catchment means rain runs off rapidly into the river. Below Hessenford, the river
widens and a distinct floodplain has developed up to 100m wide.
The Seaton valley contains several wetland features such as spring-fed floodplain
woodlands which are rare UK habitats. Land use is mainly unimproved acid grassland
on the moor with improved grasslands in the upper half of the catchment. This gives
way to arable as you move south towards the coast. There are some heavily wooded valleys,
and urban areas including Liskeard, Seaton, Hessenford, Widegates, St Cleer and Tremar.
The catchment contains two geological Sites of Special Scientific Interest (SSSI's)
- Crows Nest and Clicker Tor Quarry.
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.