Whilst volunteering at a nature reserve in Ilkley, West Yorkshire, Karen Shackleton heard from angler Steve Fairbourn that instead of catching fish on his line he was catching sanitary towels, condoms and wet wipes. He said that when it rained, raw sewage was discharged into the river.

Shackleton went out in the rain to see for herself. She found a river full of sewage: “It was gushing out and shooting straight across the river to the opposite bank and I could see sewage filling the river for as far as the eye could see. It’s like a grey discharge which makes the water go cloudy. It was absolutely shocking.”

Water companies are permitted to release raw sewage into rivers. It’s supposed to only happen in exceptional circumstances, to prevent flooding from extreme rainfall when sewers might otherwise become overloaded. Yet Shackleton discovered that raw sewage was entering the river frequently, after only short spells of light rain. This isn’t peculiar to Ilkley. In 2019 water companies in England discharged raw sewage into rivers and streams on more than 200,000 occasions and for over 1.5 million hours.

Having grown up swimming and playing in the river Wharfe, Shackleton couldn’t accept things as they were. She thought, “It might be legal, but it’s wrong”. She spoke to a local radio station and circulated photographs and footage to a local Facebook group and, in her words, “people went bananas”. Residents were outraged to see the river of their Yorkshire spa town treated as an open sewer. They decided to form the Ilkley Clean River Campaign.

Shackleton reached out to people in the community with different skill sets, including Professor Rick Battarbee, an eminent freshwater ecologist. To understand whether sewage could pose a risk to the human health of people entering the Wharfe, Battarbee needed to know the concentrations of faecal bacteria in the river. He searched for the data, assuming the Environment Agency, Public Health England or Yorkshire Water would be monitoring the water. Yet none of them was because there was no requirement to do so.

Battarbee then devised a scientifically robust method to measure concentrations of coliform bacteria. He took water samples in sterilised bottles, refrigerated them and sent them to an accredited laboratory for testing. Battarbee ran a workshop on the riverbank for volunteer samplers and Ilkley’s expert-led citizen scientists sprang into action.

In Spring 2019, Battarbee’s team, led by Fairbourn, started monitoring upstream and downstream of the Ashlands sewage treatment works. The highest level considered safe for bathing is 900 coliform units (cfu) per 100ml. When the river was in low flow, E. coli levels upstream of the sewage treatment plant were safely low, but downstream of the plant they were 35,500 cfu – almost 40 times the safe level. This meant that it wasn’t only the overflow discharges of raw sewage that were the problem. In fact, the treated sewage constantly pouring out the plant was the major source of the high levels of E. coli in the river and represented a continuous contamination threat for swimmers downstream.

When the river was in high flow, E. coli levels were high both above and below the treatment works. Battarbee now wanted to know the sources of E. coli above the treatment works. Extending the monitoring area, he found many tributaries had livestock and septic tanks creating high concentrations of E. coli but these levels were diluted when they joined the main river. He only found high levels of E. coli in the Wharfe upstream of Ilkley when the combined sewage overflow (CSO) was discharging at Addingham.

The reading at Addingham was shocking – 780,000 cfu, over 800 times the safe limit. As Battarbee explained, “that’s pure effluent”. Sewage should discharge into a receiving river with sufficient flow to carry it away but Addingham’s CSO was discharging into a small millstream which was a dry channel hidden in a wood.

In a bid for a cleaner river, the Ilkley activists decided to apply for designated bathing water status. In the UK, many coastal beaches have this status, but no rivers. Designated bathing waters are monitored for E. coli throughout the bathing season, and unsafe levels are flagged up for remedial action. Battarbee organised a landmark day of citizen science in August 2020, monitoring 60 sites along the full length of the Wharfe, including 33 sites of recreational importance. This provided a snapshot of the health of the river, with teams of volunteers testing on the same day at around the same time. Not one recreation area was found to be safe for playing in.

Battarbee is pleased to have demonstrated the efficacy of science to his community and provided data that lends weight to the group’s efforts to clean up the river. He laments how the Environment Agency has been under-funded and under-resourced, but he sees great potential for citizen science to compliment official monitoring: “Communities can offer local knowledge and enthusiasm and provide boots on the ground to hugely improve the quantity of sampling data, whilst the Environment Agency can share its professional expertise and resources to analyse the samples. We’ve done this on a shoestring budget and had real impact.”

Just before Christmas the Ilkley Clean River group made history, when the Department for Environment, Food and Rural Affairs (Defra) announced that part of the river Wharfe would be granted bathing water status, making it the first river in the UK with this designation. Ilkley’s community effort has set a precedent for other rivers around the country and inspired groups to investigate the murky waters in their own backyard and demand better.

A GUIDE TO GETTING CLEANER WATER

Research the main sources of pollution in your area. The Rivers Trust has a map of sewage outfalls in England and Wales. Your local Rivers Trust might also have information about local pollution from agriculture and other sources.

If you’re designing your own citizen science project, think carefully about what you want to measure, where and why. Ensure that your methods are scientifically robust and that your results will be credible and useful. You need to test before and after pollution events and upstream and downstream of potential pollution sources. Test in all weathers and different flow conditions.

Build on publicly available data. Look at where and when official monitoring is happening and seek to fill in the gaps. This may mean monitoring for different things or monitoring in more locations more frequently.

Reach out to local academics and experts for guidance, advice and support. FreshWater Watch can support groups wishing to test nutrient levels, such as phosphates and nitrates.

As well as gathering data, take photos and footage of pollution sources to communicate what you discover and raise awareness. Share your findings through public meetings, social media and the press.

Tell it as you find it. Don’t adopt the jargon of the environmental agencies or water companies. They might call a discharge of raw sewage a ‘spill’, which implies something accidental happening irregularly. Use plain language that accurately communicates what you discover.

A coalition is building to End Sewage Pollution, organised by Surfers Against Sewage.

You can also read more about the Ilkley Clean River group on their website, including their full citizen science reports.