2024 Bathing Water Profile for Mothecombe
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Mothecombe is at the mouth of the Erme Estuary on the south coast of Devon. It is a remote sandy bay, approximately 330 metres wide, backed by sand dunes and cliffs. A stream flows onto the beach to the sea.
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South Hams
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Devon
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A project during 2009 highlighted properties wrongly connected to the surface water system, and these have been corrected. Using a DNA tracing technique to help us identify whether sources of faecal pollution are human or animal, water sampling and walkovers throughout the catchment, and looking at ecological data has identified inputs from both human and animal sources. During 2021,2022 & 2023 we funded additional freshwater monitoring of the river Erme at two locations to build evidence, in 2023 we added Microbial Source Tracking (MST) to the freshwater sites at Sequer bridge, these samples can be put forward for DNA analysis if required. A 2022 study of the lower Erme Catchment surrounding the Bathing Water & ad hoc water quality sampling was completed to track bacteria levels. No obvious sources of pollution were identified, but many seabirds and seabird faeces were seen over the shoreline and in the estuary. Water Quality samples demonstrated elevated bacteria levels identified in several streams. In 2023 we carried out a focus walkover at the top of the Erme Estuary around Sequer’s Bridge, cattle poaching, and new dairy herds were witnessed and follow up actions have been identified.
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There are no water company assets directly affecting Mothecombe bathing water, however there are many sewage treatment works and Combined Sewer Outfalls that discharge into the River Erme which then may impact the bathing water. The sewage treatment scheme for Holbeton was completed by South West Water in July 2002. Sewage receives secondary treatment with ultraviolet (UV) disinfection and discharges to the River Erme three kilometres from Mothecombe bathing water. Storm overflow event duration monitoring (EDM) and works to reduce the frequency of twelve CSOs discharging to the Erme estuary were completed by April 2015, together with the installation of UV disinfection at Ivybridge STW. Work to reduce the frequency of discharges from CSOs in Modbury was completed by May 2015.
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The urban areas of Ivybridge, Modbury, Ermington are served by combined (surface and sewer) systems. There are no outfalls from the systems onto the beach. Improvements are being investigated at Modbury and Ivybridge sewer systems to limit storm discharges after heavy rainfall.
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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 9% of visits, with 83% of visits noting the presence of seaweed (macroalgae). This bathing water has some history of large amounts of seaweed (macro algae) and can become covered with large amounts of seaweed at certain times of the year, depending on tides and the weather. Groynes and rocks, platforms or other fixed objects may also develop a covering of seaweed which can be slippery.
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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. We are working with South Hams District Council and South West Water to identify and rectify any problems when they arise. 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 three year (2021-2023) 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. These blooms can discolour the water or form as a foam on the water. 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, tide, wind and sunlight 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 12 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 Mothecombe
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2024-09-30
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2024-05-01
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The EA will be monitoring an intensive strip of grazing at a cattle farm high in Ayleston Brook catchment, if we find associated issues linked to water quality, we will follow these up. We wish to review agriculture practices on the Womwell side of the estuary there have been reports of cattle on the beach which will have direct effects on the bathing water. SWW have been working closely with Holbeton Parish Council and a local housing developer. They are looking at whether they can extend the surface water sewer up through the village, to redirect some highway drainage and substantial field runoff away from the sewerage network. This surface water sewer would then also serve the housing development. By 2025 for Ivybridge and Modbury SWW are looking to reduce surface water entering the sewerage network from a range of potential sources. These could include highway or land drainage, groundwater infiltration, and in some cases streams. SWW are currently doing work to better understand what those sources are and the route through which they are entering the network. This will then allow them to explore possible solutions. Where there is surface or groundwater entering the sewer, SWW will work closely with local authorities to determine alternative drainage pathways for this water. Reducing non-sewage-related wastewater from the network helps reduce the need for overflows to operate. In the 2024 bathing season we will be adding a new sample to reflect the application for a new designation at Coastguard beach.
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Streams and rivers are typically affected by human sewage, animal slurry and runoff from roads. This bathing water is next to the estuary of the River Erme, and the natural effects of the wind and tide in the estuary can affect the bathing water quality. We have monitored the River Erme at Sequers Bridge since 1987, and at the mouth at Owen's Point since 1994. The river may affect water quality after heavy rainfall. The Environment Agency have also monitored the Mothecombe Stream which flows across the beach close to the Environment Agency monitoring point since 1990. The Environment Agency have found that it does not affect 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 Mothecombe 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 58% of visits. Tarry residue was not noted at this site.
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The catchment of the Mothecombe bathing water is largely agricultural with significant areas of land used for livestock, most of which are dairy and beef. During and after periods of heavy rainfall, runoff from agricultural areas to the River Erme and Mothecombe Stream is greatly increased, and the quality of the bathing water may be reduced. The Environment Agency are working with Natural England and farmers on Catchment Sensitive Farming programmes to encourage better farming practices and improve water quality in the surrounding areas. A farm campaign in 2011-2013 helped pinpoint pollution problems and extensive stretches of the watercourses have been fenced off to limit livestock access.
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The catchment surrounding Mothecombe is approximately 10,500 hectares. The Mothecombe Stream is approximately 500m long and flows directly onto the beach. The River Erme rises on south Dartmoor and flows for 25 kilometres through Ivybridge and Ermington, before reaching the estuary mouth at Wonwell and Mothecombe. The Erme Estuary is tidal as far as the weir at Flete, and like the other estuaries of South Devon, the original deep river valley has been flooded by sea level rise, to create a wide expanse of water. The catchment is mostly agricultural, with more than 50 farms.
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Mothecombe
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Mothecombe
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Sampling point at Mothecombe
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261050
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50.30957285877536
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-3.952775115720852
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47340
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Sampling point at Mothecombe
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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 26100:1
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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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