Farmer Jonathan Trower scoops up a wodge of wet wipe-resembling material from a patch of stinging nettles.
“It’s called rag,” he says. “It’s bits of cotton buds, tampons, things like that.”
It litters a field on his Stanstead Bury Farm, which lies next to Thames Water’s Rye Meads Sewage Treatment Works.
During heavy rainfall, the company can use its “safety valve” to discharge sewage diluted with water into a muddy ditch, which connects with the River Stort around 300 metres from the outfall.
When the discharge dries up, some of the material is left behind on Mr Trower’s land, which he maintains as a nature reserve with freshwater ponds and shrubland all criss-crossed by public footpaths.
“The reason this land is so special is because it’s an amazing wildlife site,” Mr Trower said, “It was a gravel pit. You can see here how nature can heal.
“Nature has healed, with quite a lot of encouragement, quite a lot of time and effort on our part to help that process.
“The consequence of that is we now have an area which is as good as you can find anywhere in this part of England, because of how we manage it with cattle, we have a small fishing club, and we have done a lot of work in terms of managing trees and getting light into the river.”
Mr Trower said he and his family “must spend thousands and thousands of pounds a year” on the site.
The field lies at the Stort Valley’s southern end. The River Stort rises near Clavering and meanders through rural Essex before it arrives in Bishop’s Stortford.
South of the town, the river is canalised as it cuts through the chalk beneath Sawbridgeworth and Harlow, through flat floodplains, some of them owned by The Wildlife Trusts and farmed using ancient Lammas cycles, with sheep or cattle grazing after the July hay cut.
Downstream from the Rye Meads Sewage Treatment Work, the Stort meets the River Lea and the flow continues towards the Thames through Hoddesdon and East London.
“The big threat is a mix of excessive flooding caused by climate change and development – concrete further up the Stort Valley,” Mr Trower said.
“We’ve noticed it over the past five years, this valley has changed out of all recognition.
“We get constant, large floods…That is compounded by the fact Thames Water pump raw sewage in flood conditions onto our land.
“When those two bodies of water meet, there is the constant threat of all that sewage ending up staying in our lakes.
“We’ve come close to catastrophe on numerous occasions over the last few years.”
Mr Trower added: “Thames Water has financial constraints and they cannot stop flooding us, because they don’t have capacity.”
He said Thames Water staff pick up rag after storm events and build barriers.
“It’s plain that this sewage works is not fit for purpose,” Mr Trower said.
“It seems incredible to me that we’re even contemplating building even a thousand houses further up the valley without sorting this out.”
Local authorities have set aside land for thousands of homes in the Stort and Lea areas over the next two decades.
Stevenage Borough Council has a target to facilitate 7,600 new homes between 2011 and 2031.
Harlow Borough Council has a local plan for at least 9,200 homes between 2011 and 2033, with Welwyn Hatfield Borough Council planning for 13,400 in its area between 2016 and 2036.
In East Hertfordshire, where Rye Meads sits, the district council has plans for 18,458 new homes between 2011 and 2033.
The authority has agreed in principle plans for 10,000 of these near the River Stort’s northern bank at Gilston.
When councillors in Hertford green-lit the decision in early 2023, they saw a draft planning condition that sets out developers must draw up a “phasing plan” with Thames Water before building, or wait until wastewater network upgrades are completed.
An East Herts Council report by planning officers reads: “Thames Water has confirmed that there is capacity at the Rye Meads Sewage Treatment Works to take foul drainage and provide treatment up until 2036, after which capacity will need to be increased.”
Thames Water has been accused of presiding over “decades of underinvestment which has led to cost-cutting and some poor decisions leaving the business in a really debilitating state” – according to the company’s own former chief executive Sarah Bentley, who made the comment on BBC Radio 5Live’s Big Green Money Show with Deborah Meaden in March 2023.
The company has debts of around £14.7billion. It has not paid dividends to external shareholders since 2017, but the firm has paid internal dividends, The Guardian has reported, including £37.5million to its parent company Kemble Water Holdings in October 2023.
Dr Kate Bayliss, from the Centre for Water and Development at SOAS University of London, looks at how water companies structure their money and debts.
She said: “Thames Water was taken over by financial investors between 2007 and 2017, and they structured the company in a way which meant they could increase debt levels more than they would otherwise have been allowed.”
The company’s shareholders include the Ontario Municipal Employees Retirement System, a pension plan in Canada, the Universities Superannuation Scheme, a pension plan for UK university staff, and China’s sovereign wealth fund, which buy into Kemble Water Holdings with hopes of a return.
Dr Bayliss added: “Fund managers who are responsible for increasing the fund’s value also sit on the board of Thames Water.
“This was all done when there was low interest, but that has changed, so Thames Water is now in a really weak position.”
Dr Bayliss said that companies had “underspent quite significantly” in recent years – by a figure thought to be around £370million.
“It’s not exactly clear why firms are underspending on infrastructure they are allowed to spend money on, but it is likely linked to increased material cost as well as skills shortages in the construction industry,” she said.
A Thames Water spokesperson said: “We have a good relationship with Mr Trower and we are in regular contact with him and aware of his concerns.
“While all discharges are unacceptable, the sewage system was historically designed in this way, to relieve pressure and prevent overflow into people’s homes.
“We appreciate how much waterways are loved and enjoyed by everyone, and we are committed to minimising our impact on the environment, but we can’t do it alone.
“Farming, industry, livestock and more extreme weather all play a role in river health.
“More investment is needed across the entire sector, as infrastructure ages and demand on it increases.
“That’s why we’ve asked for increased investment in the next regulatory cycle between 2025 and 2030.”
The spokesperson added customers should not put “unflushables” down the toilet – including wet wipes, sanitary products and dental floss.
They added the 2023/24 winter was the wettest for 11 years “causing unprecedented levels of groundwater to enter the sewage system”.