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 England and 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 the Environment Agency and 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.
At Swansea a unique model has been developed by the Smart Coasts Sustainable Communities Project that predicts water quality at the designated bathing water. The model is run during the Bathing Water season and the prediction is used to let people know if the water quality is good or poor.
This information is provided by way of a sign on the slipway to the beach, on the City and County of Swansea’s website and via twitter. The prediction is updated 3 times a day during the week and twice on the weekend. Last year the sign said good 52% and poor 48% of the time. There are 139 days in the bathing water season. On 37 of those days the sign stayed good all day. On 46 days the sign had to be changed to poor once and on 25 days it had to be changed to poor twice. On 31 days the sign stayed poor all day.
Daylight improves water quality so, generally, water quality improves as the day goes on.
For Swansea Bay’s bathing water predictions go to http://www.swansea.gov.uk/index.cfm?articleid=29433 or follow @SwanseaBayWater on Twitter.
