The beach is sandy and located on the south Gower Coast is long, wide and sweeping, backed by sand dunes and a fresh water marsh, which is a designated Site of Special Scientific Interest and a National Nature Reserve. The designated sample point is located immediately in front of the car park.
Natural Resources Wales works to establish sources of pollution around Oxwich. Some of this work is carried out in partnership with 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).
Natural Resources Wales has developed a good working relationship with Dŵr Cymru Welsh Water and liaises regularly to identify problems that could affect bathing water quality.
The outfalls from Oxwich Sewage Treatment Works and Southgate Sewage Treatment Works, are both approximately 3 kilometres either side of Oxwich beach. Neither sewage treatment works have been associated with any bathing water quality failures. Work carried out at Oxwich Sewage Treatment Works by Dŵr Cymru Welsh Water, has improved the quality of the final effluent. During the peak holiday period this treatment works operates at full capacity.
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.
Bathing water quality at Oxwich may, under certain conditions, be impacted on by the Loughor Estuary, which has a substantial natural drainage catchment to the north of the area. The catchment is predominantly agricultural and the salt marshes are heavily grazed by sheep, horses and cattle. Brash and droppings, which are believed to have originated from the salt marshes, are occasionally seen on the beach after spring tides.
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.
Nicholaston Pill flows onto the beach, a mile east of the water quality sample point. The stream runs through agricultural and forestry land, then a freshwater marsh, before emerging on the beach. During and after periods of heavy rainfall, run off from agricultural areas may affect water quality of the Pill upstream of the marsh, which in turn can impact bathing water quality at Oxwich.
Rain which falls onto the surrounding land, percolates through the rock fissures and reappears on the beach in the form of springs.
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 Oxwich 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 ten and twenty per cent of occasions. Oil and tarry residues were not noted at this site.
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 Oxwich is comprised of a gently sloping valley, extending some three miles back to the village of Knelston. A slow flowing watercourse runs down the wide valley, draining to Oxwich freshwater marsh, before emerging on the east side of the beach. The limestone rocks in the valley allow any rain falling onto the land to percolate through the rock fissures and emerge on the beach in the form of springs.
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.