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South West Water (SWW) is investigating the “high frequency” of leaks from two sewerage stations in a popular swimming river in south Devon.
Sewage discharges from storm surges at the Diptford and Moreleigh power plants increased from 128 in 2021 to 207 in 2022, according to Environmental Agency data.
The number of discharge hours increased from 450 in 2021 to 1,056 in 2022.
South West Water (SWW) said work at both sites should reduce the level of spills by the end of July.
One conservationist said he couldn’t understand what had caused the increase in the number of discharges.
The River Avon is a popular river for water sports enthusiasts and every year hundreds of swimmers take part in the Bantham Swoosh Dive from Aveton Gifford to the sea.
Storm surge discharges must operate in times of heavy rain to prevent flooding of homes and businesses.
Discharges into the River Avon at the Diptford sewage treatment works increased from 83 in 2021 to 119 in 2022, according to EA statistics.
Moreleigh storm surge discharges into Torr Brook, a major tributary of the Avon, increased from 45 in 2021 to 88 in 2022.
Environment Agency data says SWW investigations in Moreleigh and Diptford were triggered by “high frequency of spillage”.
The average number of leaks on SWW’s network dropped from 38.9 to 28.5 from 2021 to 2022, “due to a combination of dry weather and our interventions and investments,” the water company said.
SWW said it is committed to achieving an average of 20 storm surge spills per year by 2025.
The company was fined a record sum of over £2.1m in April after admitting it caused pollution at five sewage treatment plants and pumping stations in Devon and Cornwall.
He said “improvements” at Diptford and Moreleigh by the end of July “should reduce the level of spills from those locations”.
An SWW spokesperson said: “We are reducing the use of storm surges and our plan is working, but there is more to do.
“We want everyone to feel confident about their water quality and to know that we are serious about reducing our use of storm surges.
“We installed 100% monitoring on our storm surges, ahead of target.
“We are investing significantly to reduce our impact on rivers and have plans to invest in a series of storm surges that impact the Avon River.”
The nearest designated bathing site, where the water is tested by the Environment Agency, is Bantham, at the mouth of the river, where the quality was rated “excellent” in 2022.
‘Idyllic’
The River Avon, also known as the River Aune, originates in marshland on Dartmoor and flows through the South Devon Area of Outstanding Natural Beauty (AONB) to the sea.
The Doctor. Stuart Watts, president of the Aune Conservation Association, told BBC News that on a good day, the lower reaches of the river are packed with people in boats and kayaks, stand-up paddleboarding and swimming.
“It’s just idyllic, it’s wonderful,” he said.
“It’s the artery that feeds everything into the Avon Valley, which is central to the South Devon Area of Outstanding Natural Beauty and the diversity of that area depends on the river in many ways.”
He said the surges in discharges were a mystery.
“From my own experience as a gardener, 2022 has been a terrible year for rains and yet here we are in Diptford and Moreleigh having these huge increases in flushes.
“The excuse of heavy rain causing these discharges simply doesn’t exist.
“We don’t understand why they occurred, but for a significant amount of time there was sewage anyway being dumped into the river.
“We don’t know what these discharges were made of or how diluted they were.
“They say they’re going to fix them, but we don’t know what went wrong and we don’t know what they’re doing, so we’d like to know more details.”
Laurence Couldrick, chief executive of the Westcountry Rivers Trust, said an “enormous amount of pressure” on rivers also came from agricultural pollution such as manure and chemical runoff from fields.
He said the live river pollution alerts were a “vital step” and “making it publicly available even more so because it allows people to understand when it’s happening and why it’s happening”.
“People want to know when it’s safe to swim in our rivers and seas,” he said.
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