Measuring approximately 900m in length, the bay is sandy, backed by an extensive dune system, with limestone cliffs on either side. Situated on the south west coast of Anglesey, the bay is considered to be fairly remote, due to its 1 kilometre proximity from the nearest road way. The dune system is protected and listed as a Special Area of Conservation, with the beach area making up part of the Tywyn to Aberffraw Site of Special Scientific Interest, confirming the high conservation status of the Area. The site also lies within the Anglesey Area of Outstanding Natural Beauty. The water quality sample point lies at the north end of the beach, 150 metres south of the cliffs.
Natural Resources Wales continues to work to establish sources of pollution around Aberffraw. Some of this work is carried out in partnership with Anglesey 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 1st of May) and mid season if required (during the bathing water season).
There is one intermittent discharge in this catchment. Aberffraw Sewage Pumping Station discharges directly into the Ffraw upstream of the bathing water.
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. Two CSOs near Aberffraw are 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.
Phytoplankton (microscopic algae) naturally increase in number at certain times of the year. This process is known as a phytoplankton bloom.
Algal Blooms can occur at any beach during the bathing season and are usually noticeable by a surface scum. This beach has no history of such blooms.
Streams are typically affected by sewage or industrial run off from further up the catchment. The Afon Ffraw is the main river in the catchment. In terms of volume, the Ffraw is a relatively small water body. However, it does drain a large and intensively farmed area of western Anglesey and also flows through Llyn Coron. There is no evidence at present that the quality of the Ffraw represents a risk to bathing water quality.
Aberffraw Sewage Treatment Works discharges secondary-treated sewage into Aberffraw Bay. There is also a consented discharge of settled storm sewage within the catchment that discharges into the Bay. Gwalchmai Sewage Treatment Works discharges to the river quite far upstream.
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 Aberffraw, data are available for the four year assessment period from 2011-2014. Sewage debris was observed in trace amounts on less than ten per cent of occasions. Animal faeces was noted in trace amounts on a minority of occasions and in greater amounts on one occasion in June 2013. Trace amounts of litter were observed at the bathing water the majority 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.
Intensive agriculture dominates the catchment. However, there are currently no known issues with the farms in this catchment that could adversely affect the current bathing water quality. Llyn Coron and the land area upstream lie within the designated Nitrate Vulnerable Zone.
Up river from Aberffraw lie a number of isolated dwellings with private sewage treatment facilities. Natural Resources Wales does not believe these are a source of pollution to the bathing water at present. If any concerns arise, investigations will be carried out and the responsible party will be required to carry out immediate remedial action.
Poorly maintained private sewage treatment facilities could be a source of pollution, therefore the registration of all private sewage systems in Wales is 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 properties are identified in the catchment that are not on mains sewerage, Natural Resources Wales will endeavour to ensure registration has been made.
The natural drainage (hydrological) catchment surrounding the bathing water is primarily rural. The village of Aberffraw sits at the lower end of the catchment, with the rest of the area dominated by agricultural land and isolated dwellings. The River Ffraw and River Gwna drain the catchment for approximately 8 kilometres, meeting the sea at Aberffraw.
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.