A CAR park has been locked up after vans dropping off illegal waste were spotted in the site near Lobleys Drive.
Fly-tippers are being warned they could face fines of up to £50,000 if they are caught in the act by city council enforcement officers.
Passers-by alerted the city council after vehicles were seen unloading large loads of hedge cuttings, general garden waste, a vehicle tyre and a large water container.
City councillor Kathy Williams, cabinet member for environment, is calling on residents living nearby to report fresh incidents so they can come down hard on offenders.
"The illegal dumping of rubbish or waste on land not licensed to receive it is considered a serious crime and fines up to £50,000 or a custodial sentence can be given.
"It is extremely useful if residents can note the date, time and location of the occurrence, what the waste looks like and how much of it there is, a description of any vehicles involved, along with any vehicle registration number.
"I urge those employing a private waste carrier to remove their waste to ensure they are a registered waste carrier with the Environment Agency and get them to provide relevant documentation in the form of a receipt or waste transfer note that confirms their company details following payment."
Vehicles loaded up with garden waste and rubble have also been spotted in the area.
Andrew Gravells, a city councillor who lives in Abbeydale, said open spaces need to be preserved.
"I don't know why people have to spoil this amenity," he said.
"A lot of people work hard to keep our area looking good.
"It's a pretty irresponsible way to get rid of this kind of material."