Two sewage plant spills into a well-liked swimming river in south Devon are being looked into by South West Water (SWW) due to their "high frequency.". .
According to Environment Agency data, the number of sewage discharges at the Diptford and Moreleigh plants due to storm overflows increased from 128 in 2021 to 207 in 2022.
From 450 in 2021 to 1,056 in 2022, there were more hours of discharge.
By the end of July, South West Water (SWW) predicted that work at both sites would have reduced the amount of spills.
A conservationist said the reason for the rise in discharges was beyond his comprehension.
Numerous swimmers participate in the annual Bantham Swoosh swim from Aveton Gifford to the sea on the River Avon, a popular river for fans of water sports.
In times of heavy rain, discharges from storm overflows are supposed to function to prevent flooding in residences and commercial buildings.
The EA statistics show that the number of discharges from the Diptford sewage treatment works into the River Avon increased from 83 in 2021 to 119 in 2022.
Storm overflow discharges increased from 45 in 2021 to 88 in 2022 at Moreleigh on Torr Brook, a significant tributary of the Avon.
According to Environment Agency data, "high spill frequency" has caused SWW to begin investigations at Moreleigh and Diptford.
According to the water company, "a combination of dry weather and our interventions and investments," the average number of spills across SWW's network decreased from 38.9 to 28.5 between 2021 and 2022.
By 2025, SWW said it aimed to achieve an average of 20 spills per storm overflow.
When the company admitted to causing pollution at five sewage treatment plants and pumping stations in Devon and Cornwall, a record fine of more than £2.1 million was imposed on it in April.
Improvements at Moreleigh and Diptford "should reduce the level of spills from those sites" by the end of July, it was stated.
We are using storm overflows less frequently, and our plan is working, but there is still work to be done, according to a SWW spokesperson.
"We want everybody to have faith in the quality of the water and understand that we are committed to reducing the use of storm overflows.
"We've installed full monitoring on all of our storm overflows, well ahead of schedule.
"We have plans to invest in a number of storm overflows that will have an impact on the River Avon, and we are making significant investments to lessen our impact on rivers. ".
The closest designated swimming area, where water quality is monitored by the Environment Agency, is Bantham at the river's mouth, where it was rated "excellent" in 2022.
The River Avon, which is also referred to as the River Aune, rises in bogland on Dartmoor before flowing through the South Devon Area Of Outstanding Natural Beauty (AONB) and out to sea.
The lower reaches of the river are frequently crowded with people swimming, using kayaks and stand-up paddleboards, and using boats, according to Dr. Stuart Watts, chairman of the river watchdog organization Aune Conservation Association, who spoke to BBC News.
It's wonderful, it's just idyllic, he said.
"It's the artery that feeds everything in the Avon valley, which is at the heart of the South Devon Area of Outstanding Natural Beauty, and the diversity of that area is dependent in many ways on the river. ".
The rise in discharges, he claimed, was mysterious.
"From my own experience as a gardener, the year 2022 was a terrible one for rainfall, yet Diptford and Moreleigh are experiencing these enormous increases in discharges.
"It is simply not true that these discharges are caused by heavy rainfall.
"We don't know why they happened, but there was sewage being dumped into the river for a considerable amount of time.
"We don't know what was in those discharges or how diluted they were.
"They claim to be fixing them, but we don't know what went wrong or what they are doing, so we'd like to know more detail," the customer said. ".
According to Dr. Laurence Couldrick, chief executive of the Westcountry Rivers Trust, farm pollution, such as slurry and chemical run-off from fields, also puts "a huge amount of pressure" on rivers.
Live river pollution warnings, according to him, are a "vital step," and "making it publicly available is even more so because it allows people to understand when it is happening and why it is happening," he said.
People are interested in learning when it is safe to swim in our rivers and oceans, he said.
According to a representative for the Environment Agency, "We are holding the water company industry, including SWW locally, to account on a scale never seen before.
"This includes measures to address flow and storm overflow concerns, as well as stepped-up enforcement action for pollution incidents.
"Although we are unable to comment on this particular instance, we are investing a lot of time and money in studying sewer overflow compliance on a local and national level.
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