Fly-tipping in the Wensum is becoming a concern as trollies, bicycles and even a moped have been found dumped in its waters.
The city's river is appreciated around the country for being among the best of its type – a rare chalk stream.
Lucy Galvin, leader of the Green group at Norwich City Council, said: “The River Wensum is the jewel in Norwich’s crown, recognised by Natural England.
“There is also sadly the problem of fly-tipping from the banks.
“Much more could be done to recognise the importance of this river and protect it.
“A start would be a public education campaign to recognise this incredible natural asset.”
READ MORE: Slow removal of fly-tipping mess leaves campaigner annoyed
This comes as last week a moped was found dumped in the river near Oak Street in the city centre.
Gary Champion, Green councillor for Sewell ward, said: “This stretch of river by Train Wood is biodiverse and for a vehicle to be left in the river for days is detrimental to wildlife.
“My concern is that pollutants such as petrol, brake fluid, metal corrosion and hydrocarbons will restrict oxygen in the water, suffocating life and killing fish.”
Norwich City Council has recently announced £100,000 for CCTV and enforcement of fly-tipping laws, as past of the Love Norwich campaign.
A city council spokesman said: “While there is a small minority of people who are breaking the law by fly-tipping, we know this can have a large impact.
"Dumping items in the river is not only unsightly, but also can be dangerous to river users, cause pollution and, importantly, damage the wildlife in it.
"Addressing fly-tipping to keep our city clean and safe is a priority, which is why, in addition to the work we have already been doing to tackle this issue and other environmental crimes, we have committed an additional £100,000 to a Love Norwich Fund."
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