Bournemouth Hengitsbury West forms part of the 15 kilometre coastline of Poole Bay
on the Dorset coast. It is a shingle and pebble beach, approximately one kilometre
wide, and is part of the west side of the Hengitsbury Headland.
There is an emergency/storm overflow from the Hengisbury Head pumping station, that
discharges to the sea 480m from the Environment Agency monitoring point. The operation
of the overflow can lead to a drop in bathing water quality. This bathing water is
included in the Surfers Against Sewage “Safer Seas Service”. This service can alert
you to Combined Storm Sewer Overflow discharges via a phone App and in addition, it
includes the Environment Agency Pollution Risk Forecast warnings where they are available.
Further details of the service can be found at - http://www.sas.org.uk/safer-seas-service/
In the past the main water company assets affecting this bathing water were from four
storm overflows from the tunnel sewer along Bournemouth seafront. These overflows
were Hengistbury Head, Bournemouth No 1, Boscombe Pier and Fisherman's Walk. Improvements
were made to Fisherman's Walk by Wessex Water in 1993. Hengistbury Head pumping station
(PS) and combined sewer overflow (CSO), and Boscombe Pier CSO were improved in early
1999. Bournemouth No.1 PS and CSO were improved in June 1999.
Improvements to the treatment capacity and storm storage at Holdenhurst Sewage Treatment
Works (STW) were completed in 1994. Ultraviolet (UV) disinfection and additional storm
storage was installed at Holdenhurst STW by April 2001.
For the four year (2020-2023) assessment period where data is available, seaweed (macroalgae)
was not assessed as being sufficient to be objectionable, but was observed as being
present on 82% of visits. This bathing water does not have a history of large amounts
of seaweed (macro algae).
For the four year (2020-2023) 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 4% of visits. Phytoplankton (microscopic algae) naturally
increase in number at certain times of the year. This process is known as a phytoplankton
bloom. This bathing water does not have a history of phytoplankton blooms.
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.
There are no active pollution risk forecasts made at this bathing water. However any
bathing water has the potential to be affected by a pollution incident and if this
occurs a pollution risk warning with associated advice against bathing will be issued
on this website.
Sewage from the Bournemouth area is pumped to Holdenhurst (Bournemouth) STW. The outfall
from Holdenhurst STW discharges to the River Stour, north of Bournemouth. This discharge
is disinfected and designed to protect bathing water quality.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Bournemouth
Hengistbury West for the four year (2020-2023) assessment period where data is available,
sewage debris was not noted at this site. Litter was assessed as being sufficient
to be objectionable for 4% of visits, with 68% of visits noting the presence of litter.
Tarry residue was not noted at this site.
The catchment surrounding Bournemouth Hengistbury West is approximately 35 hectares.
The land is flat and there are no streams which drain directly to the beach. The area
is designated as a Site of Special Scientific Interest (SSSI)
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.