The technical article below explains why researchers from Reading believe the Environment Agency (EA) forecasting system that tells people whether it is safe to swim in bathing waters in England is not fit for purpose.
Before getting to the summary of the research, Owl, and Owl’s correspondents, have long had additional concerns.
There is the dubious method, described below, of how the EA justifies discarding highly polluted readings when awarding coveted star ratings to beaches.
Another concern, put to Owl by correspondents in the past but not discussed in this article, is whether the EA sampling is conducted where bathers actually swim.
Observation suggests not.
Jo Bateman, when interviewed on “This Morning” earlier this month, said that she first started swimming in the Exe estuary “Duck Pond” until she learned the significance of the “oily slick” that often appeared on the surface of the water.
Next door in Budleigh there are two brook outlets discharging onto the beach and the river Otter carrying whatever flows into it from Honiton and Ottery St Mary across the bay. How can the whole beach be given a single rating? Like Exmouth, there must be some sections more likely to suffer pollution than others. These problems are common to all our beaches.
Now to this opaque, but important “small print”, in the Environment Agency explanation of how bathing water quality is assessed:
“At the bathing waters where PRF [Pollution Risk Forecasting] is possible, there is an agreement with local authorities for them to display warning signs at a bathing water when a pollution risk warning is issued. If one of these warnings is seen to be in place by our samplers when taking a sample and meets relevant criteria, then the sample may be disregarded from the set which is used to make the annual classification. This is done under the ‘Short Term Pollution’ provisions of the Regulations. This provision means that the classification reflects the water quality when advice against bathing wasn’t issued, and when people are likely to be using the water.“
Owl thinks this means: bathing water quality may be “excellent 3-star” except when it isn’t!
And remember the PRF warnings only operate during the summer, yet people swim all year round. Perhaps beaches should have a summer and winter quality rating.
Sea swimmers bathing in sewage without realising due to outdated warning system
Lucie Heath inews.co.uk
Swimmers are bathing in sewage in locations that they have been wrongly told are safe because of the Goverment’s “outdated” pollution warning system, i has been told.
Researchers from the University of Reading found that the system that tells people whether it is safe to swim in bathing waters in England relies on old weather forecasting technology and insufficient sample data.
Local councils are therefore only able to provide daily pollution warnings for around 40 per cent of the country’s 424 official bathing sites in the sea and rivers, the researchers said.
Even at these sites, swimmers are not always being warned when the water quality in beaches or rivers is unsafe. as the Government’s “outdated” system is not always able to predict high bacteria levels in the sea, the study found.
The Environment Agency (EA) operates a forecasting system designed to predict when England’s bathing waters are too polluted to swim in. Separate forecasting systems are in place in Scotland, Wales and Northern Ireland.
The system combines weather forecast data with historical water quality sample data to predict the level of E.coli in the water on a given day.
When the level of bacteria is above a certain threshold, the EA issues an alert to local beach managers, who are employed by councils and put up signs to warn people against entering the water.
But the study found that warnings are not always being deployed when they should be, due to failures with the watchdog’s forecasting system.
Lead author of the report Karolina Krupska, an environmental scientist, told i one of the main problems with the system is that it does not make use of the best rainfall forecast technology available.
Water companies often release untreated sewage from pipes into bathing waters during periods of heavy rain as their infrastructure becomes overwhelmed, meaning rainfall is often a good predictor of bacteria levels in the water.
Ms Krupska said the EA could incorporate more modern rainfall prediction methods into its forecast system. She said the watchdog has already done this for its flood prediction system but the bathing water system is “behind”.
As a result, she said the bathing water system is not good at predicting sudden intense rainstorms and therefore warning of the likelihood of increased bacteria levels in the water. She added that this is a particularly problem as this type of weather is expected more often in the UK as a result of climate change.
In some instances, this can result in the system issuing warnings for the wrong locations or not at all. For example, the system failed to issue alerts for a number of popular beaches in Cornwall, following heavy storms in the areas in the summer of 2021, Ms Krupska said.
“There was a mismatch over the warnings given and what actually happened on the ground. So no warnings were given around really popular beaches in Newquay,” she said.
The study also found that the forecasting system relies on limited sample data for each bathing spot. The EA samples the water quality at bathing spots 20 times per year on random dates, meaning the samples are often not taken during a pollution event.
Ms Krupska said this means the watchdog is unable to provide warnings for all spots in England “because the model is not accurate enough to provide any kind of useful forecast”.
In 2023, the EA was only able to provide forecasts for 172 (41 per cent) of the 424 designated bathing sites in England. The forecasts are only provided during the official bathing season, which runs from May until September.
Some water companies operate their own warning systems, which are separate to the forecaster published by the EA and issue alerts when they are dumping sewage into the sea and rivers.
A final problem identified by the study is that the EA only provides pollution forecasts once per day, typically around 8am.
Ms Krupska said this means swimmers are often not made aware of pollution that occurs in the afternoon.
“Water quality changes rapidly and to keep people safe you really need to have an almost real time dynamic warning system … we don’t have that information so if something happens in the meantime the people just won’t know about the pollution until they see it or smell it,” she said.
She added: “With existing pollution warning systems, beach users don’t have good enough information to decide whether it is safe to go in the water. The science underpinning the next generation of bathing forecasting already exists, but a lack of action means these solutions have not been implemented.”
Campaigners have been calling on the EA to introduce a better system for monitoring the quality of water at bathing sites.
Among them is the University of Reading rowers who train on the River Thames, which has suffered from pollution due to sewage and chemical pollution from motorways an agriculture.
An Environment Agency spokesperson said: “We know how important our bathing waters are to local communities. That is why we monitor water quality at more than 400 beaches and inland waters across England – with more than 7,000 water samples taken and analysed during last year’s bathing water season alone.
“We already use a range of monitoring programmes and data and welcome additional research on forecasting pollution in waters, especially those used for bathing.”
Drakes Farm Seaton Road Musbury Devon EX13 8AJRef. No: 24/0342/FUL | Validated: Fri 16 Feb 2024 | Status: Awaiting decision
East Devon Watch 