2019 Bathing Water Profile for Trevaunance Cove
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Trevaunance Cove is on the north coast of Cornwall. It is a sand and rock beach resort, approximately 250 metres wide, backed by cliffs. There is a small stream that disperses over the sand.
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Cornwall
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Cornwall
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Environment Agency investigations have shown that the St Agnes stream catchment can be impacted by urban drainage as it flows through and under St Agnes. Investigations are ongoing to pinpoint and resolve these impacts and reduce the risk to Trevaunance Cove bathing water.
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There is an emergency/storm overflow from the Cove pumping station. The overflow discharges to the Trevaunance Stream 70m from the beach. There is an emergency/storm overflow from the Peterville pumping station that discharges to the Trevaunance Stream 750m from the beach. The operation of the overflows can lead to a temporary drop in water quality in the Trevaunance Stream and Trevaunance Cove bathing water. 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/
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In the past untreated effluent was discharged off Trevaunance Point very close to the bathing water. The sewage treatment scheme for St Agnes which provides Chemically Assisted Sedimentation, was completed by South West Water in 1996. The scheme also included a new relocated outfall, some resewerage and improvements to combined sewer overflows. The treatment at St Agnes STW was upgraded with ultraviolet (UV) disinfection and an advanced membrane filtration process in 2004. Storm overflow event duration monitoring (EDM) was installed at St Agnes STW, and the Peterville and Cove pumping stations by May 2011.
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The village area of St Agnes immediately behind the beach is served by a combined (surface and sewer) system.
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For the four year (2015-2018) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 4% of visits, with 87% 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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Wrongly connected domestic waste water pipes can also affect the bathing water quality. We have checked the local sewerage system for misconnections. 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.
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For the four year (2015-2018) 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.
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2019 Bathing Water Profile for Trevaunance Cove
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2019-09-30
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2019-05-01
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Streams and rivers are typically affected by human sewage, animal slurry and runoff from roads. The Trevaunance 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 outfall from St Agnes STW is discharged to the sea 640m west of bathing water. The discharge is disinfected and 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 Trevaunance Cove for the four year (2015-2018) 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 43% of visits. Tarry residue was not noted at this site.
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There are two farms in the catchment. During and after periods of heavy rainfall, runoff to the Trevaunance Stream from agricultural land is greatly increased, and the quality of the bathing water can be reduced.
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The catchment surrounding Trevaunance Cove is approximately 960 hectares, with two streams entering the sea at the beach. The Trevaunance Stream is approximately 2.2 kilometres (km) long and flows through the village of St Agnes before entering the sea at the bathing water. The Trevellas Stream is approximately four and a half kilometres long and flows through a valley which has been modified by historical mining activities. The stream enters the sea at the north eastern end of Trevaunace Cove approximately 500m from the Environment Agency monitoring point. St Agnes beacon is nearly 200m in height and is located in the northwest of the catchment, the stream valleys are generally steepest at or close to the coast. The catchment is mostly agricultural with just one or two farms. Urban areas include the village of St Agnes and there are at least three caravan sites, the rural areas are a patchwork of improved grassland and arable land. Much of the coast is designated as a Site of Special Scientific Interest (SSSI).
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Trevaunance Cove
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Trevaunance Cove
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Sampling point at Trevaunance Cove
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172220
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50.32038678132352
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-5.201232297230354
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51620
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Sampling point at Trevaunance Cove
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p152 dT23 h59 m59 s
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2019 05 01 t00:00:00
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2019-05-01T00:00:00
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2019 09 30 t23:59:59
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2019-09-30T23:59:59
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2019 31700:1
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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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