2019 Bathing Water Profile for Long Rock
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Mounts Bay is on the south coast of Cornwall. There are four designated bathing waters located around the bay - Wherry Town, Penzance, Long Rock and Marazion. All the beaches are sandy resorts backed by sea defences. Heliport beach is approximately one kilometre wide. The Ponsandane Brook flows onto the western end of Heliport beach.
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Cornwall
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Cornwall
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The Environment Agency have carried out extensive additional catchment monitoring throughout the Penzance/Marazion area of Mounts Bay alongside the Environment Agency routine bathing water monitoring. The Environment Agency are using a DNA tracing technique to help us identify whether sources of faecal pollution are animal or human, with surveys carried out in wet and dry weather conditions. The aim is to pinpoint pollution problems in the freshwater streams flowing into Long Rock and the local sewerage infrastructure, so that the Environment Agency can improve water quality at the bathing waters.
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There is a storm overflow from the Finns CSO. The overflow discharges to the Ponsandane Brook, 130m from the Environment Agency monitoring point. The operation of the overflow can lead to a temporary drop in bathing water quality in Long Rock. Within the Long Rock bathing water catchment there are three emergency/storm overflows that discharge into the Trevaylor Stream and four that discharge into the sea east and west of the bathing water.
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In the past there were a number of private discharges and combined sewer overflows (CSO) that affected this bathing water, as well as the general contamination of Penzance Bay from numerous sources. The sewage treatment scheme for Penzance and St Ives was completed by South West Water in early 1995. The scheme included extensive sewerage, improvements to intermittent discharges and the removal of untreated sewage discharges. Wastewater from St Ives is pumped to Hayle sewage treatment works (STW), where it receives secondary treatment before its discharge through a 2.7km long sea outfall west of Godrevy Head. The Hayle STW was enlarged and upgraded in 1995 and again in 2000. In 1998, further improvements were also made to CSOs at Long Rock, and Marazion pumping station CSO was sealed in November 2001. Storm overflow event duration monitoring (EDM) was installed at six CSOs in Penzance by December 2011.
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The urban area of Penzance 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 88% 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 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.
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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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This bathing water is subject to short term pollution. Short term pollution is caused when heavy rainfall or high tides wash faecal material into the sea from livestock, sewage and urban drainage via rivers and streams. At this site the risk of encountering reduced water quality increases after rainfall and typically returns to normal after 1-3 days. The Environment Agency makes daily pollution risk forecasts based on rainfall and tidal patterns and will issue a pollution risk warning if high tides or heavy rainfall occurs to enable bathers to avoid periods of increased risk. The Environment Agency works to reduce the sources of this pollution through pollution prevention measures, work with agriculture and water companies. 3 warnings advising against swimming due to an increase risk of short term pollution were issued in 2018 for Long Rock bathing water. These warnings were issued because of the effects of heavy rain on the water quality.
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2019 Bathing Water Profile for Long Rock
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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 Chy-an-dour Stream flows to the sea to the west of this beach, and the Ponsandane Brook (Trevaylor Stream) flows across the beach to the sea. The Environment Agency have monitored these streams since 1986 and found that water quality is temporarily worse during and after heavy rainfall.
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Sewage from the Penzance area is pumped to Hayle STW for treatment, and discharges to the sea off the North Cornwall coast. 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 Long Rock for the four year (2015-2018) assessment period where data is available, sewage debris was not assessed as being sufficient to be objectionable, but was observed as being present on 2% of visits. Litter was not assessed as being sufficient to be objectionable, but was observed as being present on 30% of visits. Tarry residue was not noted at this site.
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The catchment surrounding Long Rock is approximately 2,315 hectares. There are a number of streams which drain to this part of Mount’s Bay. The Chy-an-dour Brook at the western end of the beach is approximately five and a half kilometres long and flows through mining country before skirting the eastern edge of Penzance and entering the bay just east of the harbour. The Trevaylor Stream is approximately seven kilometres long and joins with the Rosemorran Stream to form the Ponsandane Brook (Trevaylor Stream) which passes through the urban area of Trevarrack before entering the bay 400 metres (m) to the west of the Environment Agency monitoring point. A small stream approximately one and a half kilometres long also drains through an underground channel 200m east of the Environment Agency monitoring point. In total the river network in the catchment is approximately 22km including major tributaries. The catchment rises in the moorland close to the northern coast and slopes steeply in the headwaters then fairly gently south to the coast. The catchment is a patchwork of improved and unimproved grassland, arable and heath. The catchment lies within part of the Cornwall Area of Outstanding Natural Beauty (AONB).
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Long Rock
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Long Rock
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Sampling point at Long Rock
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148650
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50.12634103605355
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-5.518101931147435
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31070
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Sampling point at Long Rock
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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 30300:1
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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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