Water Industry News

Spotlight On: Water Quality Of The River Wharfe

It’s safe to say that water is one of the most precious natural resources that we have. Without it, life would be impossible to sustain.


Despite this, however, water quality and quantity in the UK is under increasing levels of threat from pollution, climate change, urbanisation, ageing infrastructure, overabstraction and water mismanagement.


Pollution, in particular, is wreaking havoc on waterways around the country, with sewage, agricultural, industrial and urban runoff all converging to make river water quality worse over time.


It’s important to address this issue as quickly as possible, since rivers represent a major source of drinking water, as well as for industrial use, while supporting wildlife and biodiversity and serving as a destination for community recreation.


However, it seems as though the situation is getting worse for much of the UK, with a 2022 House of Commons Committee report concluding that there wasn’t a single river in England that was free from chemical contamination. And, in fact, just 14 per cent of rivers in the UK were classified as having good ecological status.


The River Wharfe


Interestingly, a stretch of the River Wharfe in Ilkley, Yorkshire, was the first in England to be designated as an official bathing site but in 2022 it was given a water quality rating of poor, the only bathing site in the county to fail to reach quality standards.


The river and its tributaries flow from the Yorkshire Dales National Park down to where it meets the River Ouse near Cawood, passing through lots of villages and towns on the way, including Ilkley, Addingham, Grassington, Otley, Kettlewell, Tadcaster and Wetherby.


According to the Environment Agency, water quality is one of the biggest issues facing the Wharfe catchment area, with population growth putting increasing amounts of pressure on local sewer networks. The pandemic also put smaller and more rural sewage treatment works under higher pressure because of the uptick in working from home at the time.


Add to that the rise in local tourism, with more people travelling to stay at hotels, caravan parks and campsites instead of going abroad, and sewer systems suddenly had a lot more to deal with than in the past.


Specific pollution events, point source discharges and diffuse runoff are also affecting water quality in the river and its designated bathing water.


Bridge Lane Pumping Station and Rivadale View Combined Sewer Overflow are both permitted to make discharges near the bathing site, while Ilkley Sewage Treatment Works (which is downstream of the site) is permitted to release combined sewer overflows, treated effluent and emergency discharges into the river.


To help address the problem, Yorkshire Water has been working on a new 835-metre mega sewer that will run beneath Ilkley, with the aim being to reduce the frequency and duration of these discharges into the Wharfe.


The sewer itself is two diameters in metre and is capable of storing up to 3.4 million litres of wastewater, running beneath the A65 all the way across to the wastewater treatment works. The idea is that it will hold wastewater during intense or prolonged periods of rainfall before pumping it to the treatment works to be fully treated once the rain has stopped.


The water supplier says it should reduce the frequency of discharges from the Rivadale overflow by 40 per cent, while reducing the volume of wastewater discharge during heavy rainfall events by 50 per cent, all of which will serve to improve water quality in the river.


Yorkshire Water chief executive Nicola Shaw said: “Since the river Wharfe in Ilkley was granted bathing water status we have been keen to play our part in improving water quality.


“This includes working on a variety of projects to make improvements to water quality in the river and reduce the impact of our operations. This new interceptor sewer is the largest of these projects and it will make a difference to the number of discharges into the river.

“The completion of this project is not the end of our work in Ilkley. Later this year, we will start further work to reduce discharges into the river and are currently assessing a range of possible options, using nature-based solutions where possible.”


Storm overflows can’t simply be removed from the network because this would cause potential flooding risks and rainwater needs to have somewhere to go, so finding alternative options is now necessary to help reduce discharges and pollution.


Big tanks can be built to store more wastewater and many of Yorkshire’s overflows already have these in place, keeping more water back and stopping it from entering the overflow.


Redirecting rainwater out of the network can also prove useful, with sustainable drainage options now being considered to slow the flow of water and release it back into watercourses gradually.


To help drive these plans forward, Yorkshire Water is investing £180 million with the support of shareholders to tackle storm overflow use, as well as the £147 million that is already being invested as part of its business plan.


It’s hoped that by 2025, the number of times the supplier’s most active overflows are used will be reduced by over 20 per cent compared to the 2021 baseline, which should have a positive impact on the county’s rivers and coastal waters.


Yorkshire Water also has its own Water Industry National Environment Programme underway that aims to help support the environment.


Some £500 million is being invested in phosphorus removal at 80 of its wastewater treatment sites, while just under £8 million has been invested to improve raw water quality entering treatment works through catchment management schemes.


These projects are due to be completed by the end of this year, so it’s very much a case of watch this space! Here’s hoping Yorkshire’s river water sees an uptick in quality very soon!


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