2024 Bathing Water Profile for Duporth
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Duporth is on the south coast of Cornwall. It is a privately owned sandy beach, approximately 450 metres wide, backed by cliffs and accessed by foot only.
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Cornwall
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Cornwall
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There emergency/storm overflows from the Charlestown Overflow pumping station and from the Charlestown Harbour pumping station, that discharges to the sea off Polmeor Island 400m northeast of the Environment Agency monitoring point. The operation of the overflows can lead to a temporary drop in bathing water quality.
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The need for sewage treatment around the northern part of St Austell Bay was identified to protect the bathing waters at Polkerris, Par, Shorthorn, Crinnis, Charlestown, Duporth and Porthpean. The South West Water sewage treatment scheme for Polkerris, which provides fine screening, was completed in 2003. A sewage treatment works (STW) for Par at Merthen Farm (north of Crinnis) was built by South West Water in 1992 and commissioned in 1993. The scheme included the collection of sewage from Par, Charlestown, Duporth, Porthpean and part of the St Austell catchment, and transfer via a tunnel sewer to Par STW where it receives secondary treatment before being discharged through a 1.3 kilometre (km) sea outfall south of Fishing Point in St Austell Bay. The scheme also included extensive resewerage and removal of various untreated discharges and a primary treated effluent discharge at Par Spit. The storm tank at Par STW and Harbour Road (No.2) pumping station storm overflow were improved by April 2006. The sewage treatment scheme for St Austell North (Luxulyan), which provides secondary treatment and ultraviolet (UV) disinfection, was completed in early 2006. Improvements to the storm discharge from St Austell North STW were also made at that time. Storm overflow event duration monitoring (EDM) was installed at Charlestown Harbour and Overflow pumping stations by April 2011.
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The urban area of Duporth immediately behind the beach is served by a combined (surface and sewer) system. There are no outfalls from the system onto the beach.
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For the three year (2021-2023) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 8% 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).
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For the three year (2021-2023) assessment period where data is available, phytoplankton (microscopic algae) was not noted at this site. Phytoplankton increase in number at certain times of the year and this process is known as a phytoplankton bloom. These blooms can discolour the water or form as a foam on the water. TheEnvironment Agency research shows that phytoplankton blooms can occur at this bathing water under certain conditions, but that such events are rare. 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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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.
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2024 Bathing Water Profile for Duporth
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2024-09-30
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2024-05-01
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The outfall from Par STW discharges to the sea approximately 3.1km east of this bathing water. This discharge is designed to protect bathing water quality.
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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 Duporth for the three year (2021-2023) 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 24% of visits. Tarry residue was not noted at this site.
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The catchment surrounding Duporth is approximately 31 hectares. There is one small stream 200m long which enters the sea at the southern end of the beach. The catchment slopes steadily from the west to the east. Land use is mostly urban from the village of Duporth and surrounding settlements. In the centre of the catchment there is an area of woodland.
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Duporth
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Duporth
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Sampling point at Duporth
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203520
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50.3274314014497
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-4.761868907753872
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51150
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Sampling point at Duporth
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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 27700:1
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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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