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.
