The bay faces south west towards the Bristol Channel, measuring approximately 2.5 kilometres, at low tide. The beach is made up of sand with rock pavements and pebbles at the high tide mark. The town of Porthcawl backs onto the south-east end of the bay, while the north-west end is backed by the Royal Porthcawl Golf Course. The water quality sample point is located at the centre of the beach, in line with the life guard hut.
Natural Resources Wales works with the local authority, Dwr Cymru Welsh Water and any privately permitted discharge consent holders to establish and resolve potential sources of pollution affecting water quality at Rest Bay.
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).
Storm sewer discharges near Hutchwns Point and Irongate Point can operate when heavy rainfall overwhelms the sewerage system. These protect domestic properties in Porthcawl from being flooded by sewage and storm water during heavy rainfall. There are numerous storm outfalls that discharge into the river Ogmore and its tributaries along the coast from Rest Bay. Water quality in streams or rivers may decline after periods of heavy rainfall and there could be an adverse impact on bathing water quality following periods of heavy rain, when these discharges operate.
A project known as Event Duration Monitoring (EDM) is underway to install telemetry on Combined Sewer Overflows (CSOs) within 2km of a bathing water by 2020 so that Dŵr Cymru Welsh Water (DCWW) know when the CSOs are operating and can work to reduce spills. One CSO near Rest Bay Porthcawl is included in the project.
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. Misconnections can occur in any modern urban area.
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.
Streams are typically affected by sewage or industrial run off from further up the catchment. During and after periods of heavy rainfall, run off from agricultural and urban areas will be greatly increased. This bathing water is located along the coast from the estuary of the River Ogmore. This has a large and varied catchment, which can be influenced by agricultural, urban and industrial areas. This may result in deterioration in bathing water quality at Rest Bay following periods of heavy rainfall.
Pen-y -Bont Wastewater Treatment Works discharges into the tidal stretch of the River Ogmore, approximately 7 km to the east of Rest Bay. Disinfection through ultra-violet treatment, which is designed to reduce levels of bacteria in the final effluent, which will help to improve bathing water quality is carried out. Pen-Y-Bont Wastewater Treatment Works also has a storm outlet which, when operating during times of heavy rainfall, will discharge screened effluent into the River Ogmore.
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 Rest Bay Porthcawl, data are available for the four year assessment period from 2014-2017. Sewage debris was observed in trace amounts on between ten and twenty per cent of occasions. Animal faeces was not noted at this site. Trace amounts of litter were observed at the bathing water between twenty per cent and one third of the time and in greater amounts on less than ten per cent of additional occasions. Oil and tarry residues were not noted at this site.
Natural Resources Wales continues to work with private owners regarding potential pollution sources to the bathing waters. This work involves, where necessary, advisory mail drops, dye tracing and misconnection surveys.
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 highly diverse. The town of Bridgend is located in the lower catchment, with several smaller urban areas located along the length of the tributaries of the River Ogmore. The urban areas are a mixture of residential and light industry. Further into the catchment there are some forested areas and upland hill farming, predominantly sheep.
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.