A NEW report into pollution in the River Wharfe shows that the watercourse is blighted by phosphorous and nitrogen contamination on top of what has previously been found.

Citizen science consortium iWharfe, comprising Ilkley Clean River Group and Addingham Environment Group, teamed with staff from Yorkshire Dales Rivers Trust and the Environment Agency to collect samples from 50 sites along the Wharfe on one day in August.

Now the results are in they are calling on Yorkshire Water to improve their sewage facilities. The river at Ilkley has been designated as bathing water but classified as poor due to faecal bacteria pollution.

The new study shows, says its authors, that there is also “nutrient” pollution — phosphorous and nitrogen, which can be associated with run-off water from agricultural land.

Yorkshire Dales River Trust’s CEO, Marie Taylor said: “Our previous investigations on the river have focussed on faecal bacteria contamination and threats to human health. Now this report shines a light on nutrient pollution and threats to the ecology of the river.

“Reducing nutrient pollution can be tackled by working together at the catchment scale, changing land management to provide environmental and business benefits and improving treatment of sewage effluent to make the River Wharfe a cleaner river for people and wildlife.”

Professor Becky Malby of Ilkley Clean River Group said: “The Ilkley Sewage Treatment Works is damaging our river. As well as campaigning for a radical reduction in raw sewage discharges, we have been calling for removal of phosphorus from the treated sewage for the last three years. This was previously promised, but nothing has happened. Not only is the sewage works making the river a public health hazard, it is also damaging the ecology of the river.”

The Environment Agency, which part-funded the project, also welcomed the report. Martin Christmas, Environment Agency Environment Manager for North Yorkshire said: “We are determined to improve water quality at the Ilkley site and extensive work is underway to identify sources of pollution along the River Wharfe. The data presented in the report are closely aligned with our own information and we will be considering all data carefully as we look at the next steps for the Wharfe. Our ongoing collaboration with the Wharfe team is an excellent example of citizen science in action and we look forward to continuing to work together with the local community and partners.”

Lead author of the report Professor Rick Battarbee, of the Addingham Environment Group said: “We’re currently following up some of the findings in the report especially the observation that the key change in water quality (in Ilkley) occurs between the Cromwheel Corner and Beanlands Island. Whilst it is clear that the Ilkley STW is the overall culprit there are two different discharges from the works, the storm overflow discharging untreated sewage intermittently and, further downstream, the final effluent outfall discharging treated sewage continuously. Both contain high concentrations of phosphorus and nitrogen. But which is the more important? Thanks to grants to the Ilkley Clean River Group from Ilkley Town Council and from Wharfedale Naturalists Society we are now sampling between those two discharge points and hope soon to answer this question.”