Last December, officers from the Environment Agency visited the river but found no evidence of sewage pollution, it told Mr Lewthwaite’s MP Tim Farron in an email. The river has “good status” for fish, the email said.
But a combination of sewage from United Utilities works upstream and an estimated 1,900 septic tanks used by a growing number of tourists visiting the lake is poisoning the water, local charities and scientists say.
A study carried out between 2017 and 2020 by the group Salmon and Trout Conservation found that the Leven was under “intense stress” from excess phosphorus caused by sewage.
Phosphorus pollution causes harmful algae to grow out of control, harming fish and invertebrates and the larger mammals like otters that feed on them.
Studies carried out by the South Cumbria Rivers Trust and soon to be published in a journal suggest that readings spiked at times when lots of visitors flocked to the lake and septic tank use rose, while levels dropped during Covid-19 lockdowns when tourism was banned.
Similar problems across the country
Roger Sweeting, chair of the trust, said: “A much more environmentally friendly solution is urgently needed before the salmon, charr and other freshwater organisms disappear from England’s largest lake, as well as the other less well-known water bodies.”
Local zoologist Matt Staniek, 26, who has spearheaded a campaign and crowdfunding to restore the lake, says its problems are a microcosm of those seen across the country. “It could be this summer that Windermere ends up being ecologically dead,” he says.
Lord Cavendish, a trustee of the SCRT, wants septic tanks to be registered and for owners to pay a fee, to ensure they are regularly checked and their output is regulated.
