There is an emergency/storm overflow from Cawsand that discharges into the sea 100m
southeast of the Environment Agency monitoring point. The operation of the overflow
can lead to a temporary drop in bathing water quality.
In the past there were four untreated sewage discharges that affected the water quality
at Kingsand and Cawsand beaches. These continuous discharges were removed by South
West Water in April 2001, and sewage is now pumped one and a half kilometres north
to Millbrook sewage treatment works where it is treated to a secondary standard. The
outfalls at Kingsand and Cawsand have been retained as combined sewer overflows.
Storm overflow event duration monitoring (EDM) was installed at Cawsand South combined
sewer overflow by April 2016.
The Environment Agency periodically carries out additional catchment monitoring, and
this is used to make recommendations for further improvements to protect and improve
bathing water quality.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae)
was assessed as being sufficient to be objectionable for 11% of visits, with 84% of
visits noting the presence of seaweed (macroalgae). This bathing water does not have
a history of large amounts of seaweed (macro algae).
Wrongly connected domestic waste water pipes can also affect the bathing water quality.
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 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.
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.
Streams and rivers are typically affected by human sewage, animal slurry and runoff
from roads. The Cawsand Stream enters the sea at this bathing water. The Environment
Agency have monitored the stream between 2009 and 2012, and found that water quality
is temporarily worse during and after heavy rainfall.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Cawsand 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 27% of visits. Tarry residue was not noted at
this site.
The catchment surrounding Cawsand is approximately 176 hectares. The Cawsand Stream
is approximately 1.75 kilometres (km) long and is channelled underground as it flows
through Cawsand and enters the sea at the bathing water. The steep catchment means
rain runs off rapidly into the stream.
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.