Environmental campaigners are taking the government to court for failing to stop chicken farm manure from polluting one of the UK’s most important rivers for wildlife.
The River Wye flows for 150 miles, largely along the border of England and Wales.
But the area has seen rapid expansion of poultry production in recent years, with 20 million birds being raised at any one time.
Campaign group River Action accuses the government’s Environment Agency of failing to enforce laws designed to protect waterways from agricultural activity.
It denies the claim.
Lawyers for the campaigners will tell a judicial review at the High Court in Cardiff that farmers have been allowed to dispose of excessive amounts of chicken manure on their land – far more than crops or other plants could possibly absorb – which then leaks into surrounding streams.
Charles Watson, founder of River Action, told Sky News: “If you were building cars and were allowed to do that with all your waste it would be an appalling scandal.
“That’s what’s happening on the Wye.
“Industrial waste is being dumped into nature and it has been done at such a level that it is now causing an ecological disaster. It has got to stop.”
Chicken manure is rich in phosphorus and nitrogen, vital nutrients for growing crops.
But at high concentrations in the wrong place, such as a river, the chemicals can trigger rapid growth of algae, which suck oxygen out of the water and shut out light. In effect, other plant and animal life is suffocated.
Analysis by scientists at Lancaster University has shown that about two-thirds of the 3,000 tonnes of phosphorus reaching the River Wye each year come from agriculture.
Their report recommended a reduction in poultry production in the area and said manure should be taken out of the area for disposal.
The River Wye is one of the UK’s most highly protected rivers because it is so important for wildlife. It is designated as a special area of conservation and a site of special scientific interest.
But Natural England now classifies the river’s health as “unfavourable and declining” with sharp reductions in salmon, crayfish and plant life.
Angela Jones has been swimming in the river for decades – and runs an outdoor adventure business.
She noticed a sharp decline in water quality six years ago, soon after chicken farms began to expand in the area.
“I started finding my eyes and throat would burn,” she told Sky News. “You used to be able to look at the different colours in stones below and spot fish a long way off.
“It’s just brown slime now.”
At the heart of the judicial review is the government’s 2018 Farming Rules for Water which should protect the river.
The Environment Agency said that between the beginning of April and the end of December last year it carried out 493 farm inspections and issued 285 improvement orders in the area of the River Wye and its tributaries.
In a statement it said: “We are unable to comment on ongoing legal proceedings.
“Anyone caught breaching environmental laws faces enforcement action, up to and including prosecution.”
But it’s understood that no farmers have been prosecuted in the river’s catchment area for breaking the rules.
The judicial review is expected to last two days with a judgement at a future date.