It was described as "fly-tipping on an industrial scale" - sofas, fridge freezers and bin bags left on a mountain roadside.
The rubbish was left on a route between Merthyr Tydfil and Cwm Bargoed - an area popular with hikers and mountain bikers.
Councillor Andrew Barry described the amount of mess as "jaw dropping".
Merthyr Tydfil council officers can now serve £400 fixed penalty notices for small scale fly tipping.
The powers have been granted following 2,045 complaints about the problem in the area since April 2017.
Mr Barry said: "It's domestic waste, it's commercial waste and people come all over to dump rubbish here.
"This is a beautiful area with lakes and hills, but there's a mindless minority who think it's ok to dump rubbish here.
"And when one person does it, it looks like others have followed."
He described it as "heartbreaking", but said plans were under way to clean up the area.
Mr Barry also called on residents to report anyone seen fly tipping.
Merthyr council insisted tackling the issue was a priority.
A spokesman for the local authority said Keep Britain Tidy figures for 2016-17 showed one million incidents across the UK had cost £50m to clear.
"We are still achieving our target of 100% of fly tipping cleared off council owned land within five working days," he added.
"Although we only remove waste from council-owned land, we investigate all incidents of fly tipping.
"However, it is the responsibility of the land owner to remove any waste deposited on their land."