A combined sewer overflow (CSO) which could discharge onto the beach during heavy
rainfall was removed in early 2012. Other CSOs discharge to the estuary and contribute
to pollution at the bathing water when river flows are high during wet weather.
Since 1995, the Environment Agency have worked closely with Northumbrian Water to
identify and deliver significant investment in the sewage infrastructure around this
bathing water. Most recently, an investigation by Northumbrian water into the effects
of their systems on bating water quality has led to improvements at 2 CSOs.
The Environment Agency's investigations have been aimed at identifying non water company
sources of pollution that may be affecting the bathing water so that we can implement
measures to address them. We believe that agricultural sources in the Tweed catchment
may be significant, particularly in wet weather, although we have not found evidence
pointing to any particularly important source.
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.
This bathing water is subject to short term pollution. Short term pollution is caused
when heavy rainfall washes faecal material into the sea from livestock, sewage and
urban drainage via rivers and streams. At this site the risk of encountering reduced
water quality increases after rainfall and typically returns to normal after 1-3 days.
The Environment Agency makes daily pollution risk forecasts based on rainfall patterns
and will issue a pollution risk warning if heavy rainfall occurs to enable bathers
to avoid periods of increased risk.
The Environment Agency works to reduce the sources of this pollution through pollution
prevention measures, work with agriculture and water companies.
13 warnings advising against swimming due to an increase risk of short term pollution
were issued in 2016 for Spittal bathing water. These warnings were issued because
of the effects of heavy rain on the water quality.
The Tweed Estuary discharges to the sea at the north end of the bathing water. Diffuse
run off from agricultural land and upstream settlements affects the bacteriological
quality of the river. After heavy rain, this can have a short-term impact on bathing
water quality. High river flows also shorten residence times in the estuary, exacerbating
the impact of discharges from the sewerage system in and around Berwick.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Spittal for
the four year (2013-2016) assessment period where data is available, sewage debris
was not assessed as being sufficient to be objectionable, but was observed as being
present on 1% of visits. Litter was not assessed as being sufficient to be objectionable,
but was observed as being present on 95% of visits. Tarry residue was not noted at
this site.
The catchment of the River Tweed is largely agricultural with a mixture of arable
and livestock farming. During and after periods of heavy rainfall, runoff from agricultural
areas will be greatly increased. The quality of the bathing water may be adversely
affected as a result of such events. The limited data collected on sources of bacteria
suggests that livestock may be a significant source, particularly when river flows
are high. We have engaged with the local farming community but livestock numbers in
the local catchment are low suggesting a more diffuse contribution from a wider catchment.
The River Tweed rises over 100km to the west and drains a catchment of approx 4000
sq km. The lower part of the catchment which influences bathing water quality is predominantly
devoted to arable and livestock farming. The historic town of Berwick-upon-Tweed and
its satellites, Spittal and Tweedmouth, lie at the mouth of the estuary.
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.