Viking Bay in Broadstairs is a 300 metre sandy horse-shoe shaped bay, with cliff-top promenade, harbour pier and boardwalk. The small harbour is home to working boats, an active sailing club and resort facilities.
This bathing water failed standards in 1996 and investigations identified and repaired two areas of collapsed and silted up foul sewer in Harbour Street. Following a failure in 2004, a series of investigations were carried out between 2004 and 2007 and more recently in 2015. Many potential sources of contamination were investigated which pointed to the fact that the surface water outfall is the source of contamination, although levels of contamination are comparable with other similar systems. It is likely that diffuse sources typical of an urban catchment all contribute to the contamination. Measures to reduce contamination in the surface water system are on-going.
Viking Bay bathing water could be affected by discharges from storm overflows that can occur when heavy rainfall overwhelms the sewerage system. The Winterstoke storm overflow at Ramsgate is less than 3 km to the south and the North Foreland storm overflow is offshore nearly 5 km to the north east. These outfalls are designed to protect bathing water compliance.
Prior to March 2007 there was a screened crude sewage discharge from the North Foreland 5 km long sea outfall. There was also a storm discharge from a 400 metres outfall from the same pumping station. In March 2007 the North Foreland long sea outfall became a high frequency storm overflow and the short outfall was converted to an emergency outfall. Sewage flows were diverted to full treatment (including UV disinfection) at Weatherlees sewage treatment works before being discharged via the Margate long sea outfall.
A partnership group between the Environment Agency, Thanet District Council, Kent County Council and Southern Water has been formed. The aim of the partnership is to work together to better understand risks to bathing water quality and put measures in place to make improvements.
For the four year (2015-2018) assessment period where data is available, seaweed (macroalgae) was assessed as being sufficient to be objectionable for 22% of visits, with 69% of visits noting the presence of seaweed (macroalgae). The shore can become covered with seaweed, depending on tides and the weather. Groynes, rocks and other fixed objects may have a covering of seaweed which can be slippery.
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.
For the four year (2015-2018) assessment period where data is available, phytoplankton (microscopic algae) was not assessed as being sufficient to be objectionable, but was observed as being present on 2% of visits. Phytoplankton (microscopic algae) increase in number at certain times of the year. This process is known as a phytoplankton bloom. Blooms of phytoplankton can result in the water appearing discoloured or a foam forming on the water.
The risks to human health from contact, ingestion or inhalation with marine algae that currently occur in UK coastal waters are considered to be low. However, some individuals may be more sensitive and display some reactions.
A common marine algae found in UK coastal waters is Phaeocystis, which is often mistaken for sewage as it forms foam and a brown scum, but it is non-toxic.
Environment Agency samplers make observations of litter present on the beach at every visit, this includes assessments of sewage debris, litter and tar. At Broadstairs, Viking Bay for the four year (2015-2018) assessment period where data is available, sewage debris was not noted at this site. Litter was not assessed as being sufficient to be objectionable, but was observed as being present on 61% of visits. Tarry residue was not noted at this site.
There are no natural surface water courses that flow to the coast from the local catchment of about 240 hectares. The Stour catchment of about 823 square kilometres drains into Pegwell Bay over 6 km to the south. The Stour catchment includes Ashford, Canterbury, Sandwich and much of Deal.
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 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 role to drive improvement of water quality at bathing waters that are at risk of failing higher 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.