Video report by Granada Reports correspondent Rob Smith
A water supply company is not being transparent about how much sewage is being dumped in North West rivers, a university professor has claimed.
Jamie Woodward, Professor of Physical Geography at Manchester University, also said United Utilities was not working hard enough to clean up the rivers in the region.
It comes after the UK's Secretary of State for Environment, Thérèse Coffey demanded water companies reveal plans for how they will decrease the amount of sewage being released into rivers.
Professor Woodward said until the worst offending locations are highlighted, improvements cannot be made to the the environment and industry.
He said: "Water companies in England have failed to invest sufficiently in wastewater treatment and sewerage infrastructure to keep pace with increasing populations and more intense rainfall.
"To take pressure off their sewer networks, companies allow huge volumes of untreated wastewater and sewage to be dumped into our rivers and coastal waters."
He added: "Sewage pollution incidents - many of which were legal - increased 29-fold over five years and countless urban rivers are now effectively extensions of the sewerage network. Our rivers are running out of time."
Recent figures have revealed that just 14% of rivers in England have “good” ecological status.
It has been reported that figure could fall to just 6% by 2027.
Professor Woodward, who specialises in rivers, also said that it is clear "when sewage was dumped, but not how much" causing him to believe there is something missing in the data.
How are sewage discharges recorded?
Professor Woodward added: "Sewage discharges to rivers are recorded by sensors known as event duration monitors.
"These measure the start and end time of any flow, but are rarely set up to measure the volume of that flow," therefore allowing data to be manipulated.
He added: "Was an 'event' 100 litres or one billion litres?
"One billion might sound far-fetched, but Mogden sewage works next to Twickenham Stadium discharged over one billion litres of sewage directly into the River Thames on each of two days in October 2021."
This highlights the potential for a water company to "reduce the duration and frequency" of when they are discharging sewage, while still being able to increase the total amount that is being dumped into a river.
What needs to happen?
"People need accurate information on what is happening to their local rivers so they can identify the worst offending discharge sites and hold water companies to account," Professor Woodward said.
The 2021 Environment Act requires water supply companies to make near real-time data regarding the frequency and duration of sewage discharges available to the public before 2025.
In a landmark 2022 report on river pollution, the Environmental Audit Committee recommended that the government ask water suppliers to record wastewater discharge volumes. But the government argued it was too expensive.
Professor Woodward is now urging Thérèse Coffey to reconsider the recommendation in order to "tackle this scandal".
"If Thérèse Coffey is serious about tackling this scandal, she must reverse that decision."
A United Utilities spokesperson, said: "We care passionately about the customers, communities and environment we serve.
"We are already investing £230m to reduce the frequency of storm overflow operations by a third by 2025.
The statement continues: "We know that there is more to be done though. With the largest combined sewer network in the country and 28% more rainfall in our region than the UK average, our investment plans from 2025 onwards will see one of the biggest environmental improvement programmes in the country."
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