Introduction
Wessex Water was the first company to provide near real-time bathing water notification through its Coast and Rivers Watch service. The service, which started in April 2012, goes beyond the bathing season and reports on when overflows are in use throughout the year.
Discharge alerts are generated automatically by our telemetry system, taking data from monitoring devices at the overflows and conveying it outwards using phone lines or mobile cell technology.
The information is provided to organisations and the public about when our storm overflows have operated, in near-real time.
We have focussed on those overflows most likely to affect the 48 designated bathing waters in our area and other popular waters used by bathers, paddlers, divers or water sports enthusiasts. In partnership with the Environment Agency (EA), we set up a system that provides near-real-time information on when these overflows have discharged. The data can be seen on our website and is also provided to Surfers Against Sewage for use on their SaferSeas App.
The data is also given to local authorities, the EA, shellfisheries and other interested parties direct by email, which allows them to act and notify onwards where necessary.
About storm overflows
Storm overflows are used during heavy rainstorms to protect properties from flooding and to prevent sewage from overflowing into streets and homes. As storm overflows should only operate during periods of intense rainfall, any foul water released from them will be very dilute because of the large volumes of rainwater flowing through the sewers.
Storm overflows have always been part of the sewerage network in the UK because the majority of sewers carry both rainwater and foul sewage and they prevent properties from flooding following intense rainfall. We are now getting more intense rainfall storms due to climate change.
There are two main approaches to eliminating overflows; separation to stop stormwater from entering combined sewers, or constructing large storage tanks, which would have significant carbon consequences, cost billions and would be hugely disruptive.
We need Government to change legislation so developers cannot connect surface water drainage to combined sewers which is making the matter worse. There is also the need for water companies to be able to release rainwater only directly into a watercourse.
Ofwat, the economic regulator, needs to prioritise investment, which it tightly controls to keep bills down, so water companies can get on and help solve the problem.
Since 2000 Wessex Water has invested £181m to improve nearly 600 storm overflows across the region, with a further £150m set aside for improvements between 2020 and 2025. We also work with farmers on catchment management to help reduce run-off, which is a major factor in river/sea water quality, as well as tackling misconnections and educating our customers on how to avoid sewer blockages that cause pollutions.
Factors affecting water quality
Faecal Indicator Organisms (FIO) or bacteria can come from many sources including sewage (both public and private sewerage systems), run-off from fields and agricultural livestock, wildlife, birds and road drainage.
These bacteria are used to measure compliance with Bathing Water standards and are based on World Health Organisation research that recorded the frequency of stomach upsets in people bathing in differing water quality.
The concentration of these bacteria indicate a risk to the bather's health if the water is ingested; the greater the concentration the higher the risk of illness. Excellent bathing water quality does not mean that there is no risk of illness to bathers if ingested, rather that the concentration of bacteria and risk of illness is lower than when water quality is good or less than good. The safe standard for ingesting these bacteria is zero (set under the Drinking Water standards) and any concentration above this can cause illness. Untreated river or sea water is never safe to ingest because it contains bacteria and other contaminants and pathogens such as pesticides, and causes illnesses like leptospirosis (Weil's disease).
Working in partnership
We recognise that the quality of our recreational waters is a complex picture, with many contributing factors and stakeholders.
Working together with the Environment Agency, councils and local groups is the only way to better understand the impacts on recreational waters from storm overflows and other sources, the changes we can all make and longer-term solutions to enable us to enjoy our watercourses, coasts and seas.
Warleigh Weir investigation
We are undertaking an investigation centred around Warleigh Weir, on the River Avon, near Bath. Our work is focussed on understanding the current water quality of the river upstream of Warleigh, including tributaries such as the Frome and Midford Brook, against bacteriological standards, the sources of bacteria and options to reduce concentrations at Wessex Water’s assets, private treatment works and wider diffuse rural and urban locations. In addition to this investigation, we are working with an Artificial Intelligence (AI) provider to develop a real-time water quality notification system.
There is currently no technology that can continuously measure the concentration of these bacteria in rivers, which means it is not possible to provide people with this information in real time. Instead, samples have to be collected by hand and taken to a laboratory where the bacteria are analysed under controlled conditions, which takes around three days.
However, there are many readily available sensors that can provide robust real-time measurements of other water quality indicators, including temperature, pH, conductivity, dissolved oxygen and river flow. We are working with UnifAI, a company specialising in the use of AI technology, to trial an approach that uses algorithms to develop relationships between these readily measurable parameters and the concentration of bacteria in water.
The trial, which will take place between 2021 and 2023, will involve installing a series of sensors, collecting water samples and analysing bacteria in the laboratory. As more data is collected, the AI will develop these relationships, which will hopefully allow us to stop analysing samples in the laboratory and start providing the public with real-time water quality notifications about the level of public health risk.
Litter Free Coast & Sea
We have been working with the Litter Free Coast & Sea partnerships in Dorset and Somerset for nearly ten years. These are partnership-based projects focussing on the key issues of interest to local communities. The partnerships include Local Authorities, the Environment Agency, Catchment Partnerships and other stakeholders who are passionate about the quality of the coast and sea.
Activities are very varied, including developing local beach clean groups; running events for local communities to raise awareness, such as ‘Only Rain Down the Drain’; working with businesses to improve waste practices and reduce litter; and education opportunities within schools.
Examples of some of the projects are shown below, with more information available at Litter Free Coast and Sea – Dorset & East Devon.
BCP Council and shellfisheries
It is not just bathing or recreational waters which can be impacted by elevated bacterial levels from a wide range of sources. Within the Wessex region there are many designated Shellfish Waters, particularly in Poole Harbour, which support business and economic activities associated with shellfish production, sales and export.
During AMP7 (2020-2025) we are undertaking an investigation within Poole Harbour to better understand the bacteriological contributions from our assets (water recycling centres and storm overflows) compared to other sources. This will help to inform whether we do impact concentrations within shellfishery areas and if so, the level of impact.
In addition to this investigation, we are working with Bournemouth, Christchurch and Poole (BCP) Council, the local shellfishery businesses, the Centre for Environment, Fisheries & Aquaculture Science (CEFAS) and an AI provider (UnifAI) to better understand the conditions that can cause a decline in water quality impacting shellfish harvesting. This is using water quality, bacteriological and norovirus data collected by all partners and linking this with data from sensors, asset operation, weather and tides to help predict when water quality may decline to notify shellfishery businesses to reduce harvesting, wastage and the reputational risks associated with recall notices, for example.