This is a small and tidal cove, found on the south east of the Gower peninsular. On a high tide the beach is almost non-existent and pebbly, but on a low tide, the sand is exposed, along with numerous rock pools. A coastal path joins Limeslade with Rotherslade, Langland and Caswell Bay. The water quality sample point is located at the centre of the Bay.
Natural Resources Wales works to establish sources of pollution around Limeslade Bay. Some of this work is carried out in partnership the Swansea Council and Dŵr Cymru Welsh Water.
Inspections are carried out by Natural Resources Wales in partnership with the local authority and the water company. These are carried out pre-season (before the 15th of May) and mid-season if required (during the bathing water season).
Following several bathing water sample failures, Natural Resources Wales carried out visual inspections and water quality sampling of the culverted surface water drain. Investigations concluded that the drain was polluted by wrongly connected waste water pipes from household sinks and washing appliances.
It is believed that, this has been the cause of some bathing water failures at Limeslade. Natural Resources Wales has been working with the Swansea Council and Dŵr Cymru Welsh Water to trace the pollution back to individual properties and resolve the problem.
Limeslade Pumping Station has an emergency overflow, which can discharge to the west of the beach if there is a breakdown at the pumping station.
Mumbles (Knab Rock) Sewage Pumping Station has an emergency and storm overflow, approximately a mile from the water quality sample point. This can discharge off Mumbles Head, but only at certain times of an ebbing tide.
A project known as Event Duration Monitoring (EDM) is underway to install telemetry on Combined Sewer Overflows (CSOs) by 2020 so that Dŵr Cymru Welsh Water (DCWW) know when the CSOs are operating and can work to reduce spills.
Until 1999, Swansea's sewage was discharged directly to the sea from the Mumbles Headland, less than 1.5 kilometres away. In 1999, Swansea's sewage system was significantly upgraded, when a new Wastewater Treatment System was installed at Fabian Way. This resulted in a vast improvement to the water quality at Limeslade Bay.
More recently, Natural Resources Wales has been working with Dŵr Cymru Welsh Water to trace the sources of pollution in the public and private surface water drains of the Limeslade catchment.
Natural Resources Wales works closely with Swansea Council to monitor and maintain bathing water quality at Limeslade. Meetings are held on a quarterly basis. Investigations and inspections are carried out in collaboration.
At Limeslade, Natural Resources Wales has been working with Swansea Council to trace the sources of pollution in the public and private surface water drain back to individual properties. The Council then work with the owners to stop the pollution at the source.
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.
Phytoplankton (microscopic algae) naturally increase in number at certain times of the year. This process is known as a phytoplankton bloom. These algal blooms can occur at any beach during the bathing season and are usually noticeable by a surface scum. This beach has a history of such blooms.
Natural Resources Wales samplers make visual observations of the beach at every visit. This includes assessments of sewage debris, animal faeces, litter and oil or tar. At Limeslade Bay, data are available for the four year assessment period from 2015-2018. Sewage debris was observed in trace amounts on less than ten per cent of occasions. Trace amounts of animal faeces were noted at the site on a minority of occasions. Trace amounts of litter were observed at the bathing water on between thirty and forty per cent of occasions. Oil and tarry residues were not noted at this site.
Natural Resources Wales continues to work with private owners to address potential pollution sources to the bathing water. This work involves where necessary, advisory mail drops, dye tracing, misconnection surveys and face to face meetings.
Poorly maintained private sewage treatment facilities could be a source of pollution, therefore the registration of all qualifying private sewage systems in Wales was required by 30 June 2012. The primary aim of this exercise is to provide increased protection for the environment and sensitive features such as bathing water beaches. Where discharges from properties are identified in the catchment that are not on mains sewerage, Natural Resources Wales will endeavour to ensure registration has been made, unless already a permitted discharge.
The natural drainage (hydrological) catchment surrounding the bathing water is a narrow steep valley. There are no watercourses running onto the beach, but the rocks in the area are limestone, which allows any rainfall to percolate through the rock fissures and resurface at the beach. Some of the rain falling in the catchment is directed into a surface water drain, which flows onto the rocks at the top of the beach.
The area is relatively urban and residential, with a cricket ground and allotments at the top of the valley.
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.
The majority of sewers in Wales 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.
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.
It is Natural Resources Wales' role to drive improvement of water quality at bathing waters that are at risk of failing European 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. The following sections serve to highlight potential sources of pollution, conditions under which they may arise and measures being put in place to improve water quality.