Seaton Carew is a small resort on Tees Bay to the south of Hartlepool. Seaton Carew
North is the northern end of an extensive sandy beach fronting the town.
Bathing water quality may sometimes be affected by discharges from storm outfalls.
Storm overflows may operate during and after rainfall when the sewerage system can
be overwhelmed by the amount of surface water entering it. These overflows prevent
sewage from backing up pipes and flooding properties. Overflows discharging into streams
and along the shore can also contribute.
The outfall from an overflow at Mainsforth Terrace, which also carries the Burn Valley
stream, has recently been repaired.
Other overflows discharge to the Stell but have done so for 20 years during which
bathing water quality has improved. Whether these have changed recently is included
in the current investigations.
Investigations into the performance of the sewerage system are due to be completed
by 2016 and any improvements identified as necessary will be implemented with a target
for completion before the 2018 bathing season.
Sewage from Seaton Carew and Hartlepool was discharged to sea via a number of short
sea outfalls until 1993. A long sea outfall was constructed then and these flows were
diverted over three kilometres offshore to improve and protect bathing water quality
at the Seaton Carew beaches.
In 2000, a treatment works was built at Seaton Carew and the sewage flowing to the
long sea outfall has since received full treatment and disinfection using ultraviolet
light. In 2007, the discharge from Billingham Sewage Treatment Works was diverted
from its previous location to this long outfall to ensure that it had no adverse effect
on the ecologically important area at Seal Sands.
However, in recent years, bathing water quality has declined, leading to renewed investigations
by both Environment Agency and Northumbrian Water.
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.
12 warnings advising against swimming due to an increase risk of short term pollution
were issued in 2017 for Seaton Carew North bathing water. These warnings were issued
because of the effects of heavy rain on the water quality.
The Stell crosses the bathing water. There are a number of consented discharges to
this watercourse which may impair water quality during and immediately after heavy
rain. The current investigations include determining whether anything has altered
which would increase their impact on bathing water quality to explain the observed
deterioration.
Environment Agency samplers make observations of litter present on the beach at every
visit, this includes assessments of sewage debris, litter and tar. At Seaton Carew
North for the four year (2014-2017) 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 12% of visits. Tarry residue
was not noted at this site.
The beach is close to the mouth of the River Tees, which has a catchment of approximately
2000 square kilometres. It rises in Pennine moorland, draining a largely agricultural
catchment before reaching the sea via an urban/industrial estuary. Within this, smaller
streams drain an area of approximately 18 square kilometres, mainly the southern half
of Hartlepool and reach the sea close to this designated beach and are probably more
relevant.
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.