Campaigners fear the River Wensum is under increasing pressure after drought, pollution and low water levels led to fish deaths.
Campaigners say Norfolk's River Wensum is showing signs of increasing environmental stress as drought, pollution and low water levels continue to affect the protected chalk stream.
Their concerns follow the recent discovery of hundreds of dead fish in the river through Norwich, with the Environment Agency investigating the incident.
The agency believes a combination of prolonged hot weather, exceptionally low river flows and reduced oxygen levels created difficult conditions for aquatic life. Officials also say heavy rainfall after the dry spell is likely to have washed polluted surface water from roads and drains into the river, further reducing water quality.
The River Wensum is one of England's internationally important chalk streams and is designated as a Special Area of Conservation because of its rare habitats and wildlife. Environmental groups say the river has faced growing pressure in recent years from pollution, abstraction and climate change, with prolonged dry weather making those challenges even more severe.
Environment Agency officers continue to monitor oxygen levels, water quality and the condition of the river while assessing the impact on fish populations.
Campaigners are calling for continued investment in protecting the Wensum, warning that improving water quality and restoring healthy river flows will be essential if the river's wildlife is to recover and thrive in the future.

Dereham Man Jailed Over Cocaine Supply
Two More Broadland Communities Become Mindful Villages
Norfolk Churches Awarded Heritage Repair Funding
Woman Dies Following Bradwell Collision
Mother Received ‘I’m Sorry’ Message After School Stabbing
Norfolk Hazardous Waste Days Return
Great Yarmouth Council Workers Plan Two-Day Strike
Temporary Emergency Department Planned At Norfolk Hospital
Great Yarmouth First Leader Quits Restore Britain
New Broads Chief To Hear Boaters’ Toll Concerns
Cromer Teen Filmmaker Premieres Second Feature
Winter Grants Open Across Broadland And South Norfolk
New Festival Celebrates Norwich’s Rivers
Man Charged With Murder Of Dersingham GP
Suffolk PCC Opposes RAF Barnham Asylum Plans
Norfolk Fire Staff Honoured At Annual Awards
Traffic Concerns Raised Over Carrow Regeneration

