Measuring approximately 2 kilometres in length, this isolated beach is sandy, with a pebble bank above the high tide mark, backed by steep limestone cliffs. Marloes Sands faces south east into the Bristol Channel, towards Stockholm island. The surrounding land is predominantly agricultural, with the small town of Marloes located 1.3 kilometres north west of the bay. The coastal waters and coastal belt form part of the Pembrokeshire Marine Special Area of Conservation and is also designated as Special Site of Scientific Interest, confirming the high conservation status of the area. The bathing water also lies within Pembrokeshire Coast National Park. The water quality sample point is located at the centre of the bay.
Natural Resources Wales works with Pembrokeshire County Council and Marloes & Dale Community Council, to maintain the excellent bathing water quality at Marloes Sands. 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.
Natural Resources Wales and Pembrokeshire County Council have been working together to monitor and maintain the bathing water quality at Marloes for a number of years.
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 does not have a history of such blooms.
There is a small stream which runs onto the beach. The water quality of this stream is usually very good, but may deteriorate during periods of heavy rainfall.
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 Marloes Sands, data are available for the four year assessment period from 2020-2023. 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 and thirty percent 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.
Natural Resources Wales places a high value on public participation in helping to trace sources of environmental pollution. Natural Resources Wales welcomes any comments or information from the pubic with regards to environmental pollution.
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.
