2024 Bathing Water Profile for Portmellon
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Portmellon is on the south coast of Cornwall. It is a remote sandy beach, approximately 150 metres wide, backed by hills. Rock pools are accessible at low tide.
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Cornwall
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Cornwall
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In 2013-2019 the Environment Agency carried out extensive additional catchment monitoring alongside routine bathing water monitoring. The aim of this work was to pinpoint pollution problems in the catchment and improve water quality at the bathing water. Surveys were carried out in wet and dry weather conditions. Environment Agency officers also walked up the Portmellon Stream and its tributaries to identify potential sources of bacterial contamination to the stream. A DNA tracing technique helped identify whether sources of faecal pollution were animal or human. The sources of pollution were found to be mainly agricultural in wet weather and from cattle watering in streams in dry weather. There may also have been an additional source from propagation of bacteria in seaweed.
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There is an emergency/storm overflow from the Portmellon pumping station, that discharges into the Portmellon Stream 70m upstream of the bathing water. The operation of the overflow can lead to a temporary drop in water quality in the Portmellon Stream and Portmellon bathing water.
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There is no water company scheme associated directly with this bathing water. The Gorran Churchtown sewage treatment works (STW) is two and a half kilometres inland and discharges sewage treated by filter beds to the Portmellon Stream. South West Water improved Gorran Churchtown STW in 1999. The Portmellon pumping station pumps local sewage via Mevagissey to Menagwins (St Austell) STW for treatment. Storm overflow event duration monitoring (EDM) was installed at Gorran Churchtown STW and Portmellon pumping station by April 2011. Further improvements to Gorran Churchtown STW are scheduled to be completed by March 2025.
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For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 73% of visits, with 22% 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 has a history of large amounts of seaweed.
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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 0% of visits noting the presence of phytoplankton (microscopic algae). 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.
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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 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 1 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.
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2024 Bathing Water Profile for Portmellon
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2024-09-30
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2024-05-01
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Streams and rivers are typically affected by human sewage, animal slurry and runoff from roads. The Portmellon Stream flows onto this beach. The Environment Agency have monitored the stream since 1986 and found that water quality is temporarily worse during and after heavy rainfall.
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The Gorran Churchtown STW outfall discharges to the Portmellon Stream two and a half kilometres upstream of the bathing water. This STW can affect the water quality of Portmellon Stream.
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Environment Agency samplers make observations of litter present on the beach at every visit, this includes assessments of sewage debris, litter and tar. At Portmellon for the four year (2020-2023) assessment period where data is available, sewage debris was not noted at this site. Litter was assessed as being sufficient to be objectionable for 2% of visits, with 14% of visits noting the presence of litter. Tarry residue was not noted at this site.
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There are approximately 20 farms in the catchment, most of which are used for livestock. During and after periods of heavy rainfall, runoff to the Portmellon Stream from agricultural land is greatly increased, and the quality of the bathing water can be reduced.
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The catchment surrounding Portmellon is approximately 715 hectares. The Portmellon Stream including tributaries is approximately 10 kilometres (km) long and flows through a steeply sloping woodland valley. The stream collects water from various tributaries which come together approximately one kilometre from the bathing water. Land use is agricultural, with around 20 farms. It is mainly improved grassland with smaller amounts of arable land and woodland. The urban areas are Portmellon and Gorran Churchtown. The catchment is partly within the Cornwall Area of Outstanding Natural Beauty (AONB).
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Portmellon
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Portmellon
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Sampling point at Portmellon
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201560
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50.26182964398326
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-4.785574720409609
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43920
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Sampling point at Portmellon
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p152 dT23 h59 m59 s
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2024 05 01 t00:00:00
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2024-05-01T00:00:00
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2024 09 30 t23:59:59
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2024-09-30T23:59:59
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2024 28100:1
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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.
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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.
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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.
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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.
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Discharges from sewage treatment works have improved substantially in England since the 1980s.
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