Porthleven Sands bathing water is at the western end of Porthleven Sands on the south coast of Cornwall. It is a shingle beach resort approximately 330 metres wide backed by cliffs.
In 2019 – 2022 the Environment Agency carried out additional catchment monitoring of Porthleven Stream alongside routine bathing water monitoring. Site visits were also carried out to identify sources of bacteria to Porthleven Sands bathing water. These investigations showed that the most likely sources of bacteria were from misconnections of foul drainage (toilets, sinks, washing machines etc.) from properties in Porthleven to the surface water drainage network, which discharges to sea near the bathing water. We are working closely with South West Water to identify the locations of these misconnections – a number have already been resolved and work continues to identify more. Catchment monitoring and site visits are also continuing, to assess the ongoing impact of the misconnections and inform further remedial actions.
In 2019 Glanvilles carried out a survey of the surface water sewer that discharges at end of harbour wall to assess potential for contamination from foul sewer. The EA carried out harmonised monitoring of Porthleven bathing water and stream. We also included Microbial Source Tracking (MST) analysis and increased sampling frequency from 10x to 20x per season. No elevated results were recorded in 2019. Additional monitoring of Porthleven Stream was carried out alongside BW monitoring during 2021 bathing season.
In 2022 the Environment Agency continue to sample the surface water discharge pipe, to understand the impact of sources of pollution. MST analysis is still suggesting human sources; therefore, we will continue to investigate misconnection issues and sources of sewage.
In 2023 Misconnection work has shown dramatic improvements. The surface water pipe will be re-visited for further sampling in 2024.
There are emergency/storm overflows from the pumping stations at Breageside, and Harbour Tank. These overflows are, and discharge into the sea near Porthleven Harbour entrance. The operation of the overflows can lead to a temporary drop in bathing water quality at Porthleven Sands.
This bathing water is included in the Surfers Against Sewage “Safer Seas Service”. This service can alert you to Combined Storm Sewer Overflow discharges via a phone App and in addition, it includes the Environment Agency Pollution Risk Forecast warnings where they are available. Further details of the service can be found at - http://www.sas.org.uk/safer-seas-service/
The South West Water sewage treatment scheme for Porthleven, which provides secondary treatment and ultraviolet (UV) disinfection, was completed in early 1997. Storm overflow event duration monitoring (EDM) was installed at the Breageside, and Harbour Tank pumping stations by April 2011.
In 2021, SWW partially screened the end of the contaminated surface water pipe and regularly check it to confirm it as the source of sanitary items found in the harbour. The source of the items has been attributed to a number of misconnected properties. SWW have worked with the homeowners to resolve some of these and working to resolve several more - at least 10 private foul drainage systems (including toilets) incorrectly connected into the surface water system
The urban area of Porthleven immediately behind the beach is served by a combined (surface and sewer) system. There are no outfalls from the system onto the beach.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 4% of visits, with 74% of visits noting the presence of seaweed (macroalgae). This bathing water does not have a history of large amounts of seaweed (macro algae).
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.
The EA will continue to work with SWW to influence and track the progress of misconnections work in the village. The EA will continue to work with Porthleven Environment Group to monitor ongoing sewage debris in the harbour and therefore ongoing risk to Bathing Water from misconnections in the village.
Streams and rivers are typically affected by human sewage, animal slurry and runoff from roads. The Porthleven Stream flows into the sea through the harbour. The Environment Agency have monitored the stream upstream of the harbour between 1994 and 2008, and found that water quality is temporarily worse during and after heavy rainfall.
The outfall from Porthleven STW discharges to the sea near Porthleven Harbour entrance. This discharge is disinfected and 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 Porthleven Sands 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 12% of visits. Tarry residue was not noted at this site.
The catchment surrounding Porthleven Sands is approximately 1,290 hectares. The Porthleven Stream (also known as the Methleigh Stream) is approximately four kilometres long. It flows from Carnmeal Downs to Porthleven Harbour 250m west of the bathing water. The catchment is fairly steep with a patchwork of arable land, improved grassland and more natural grassland. The area also includes the settlements of Porthleven, Breage and Sithney.
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.