Experts believe allowing nature to take its course is the best way to preserve a Sussex beauty spot for future generations.
The Environment Agency plans to allow Cuckmere Valley to be flooded by the sea, as the river banks are reaching the end of their life and need to be reinforced.
But the scheme faces opposition from a group of local people led by publishing chief executive Nigel Newton, who say allowing the valley to flood would destroy the Seven Sisters Country Park.
Even though they do not own the land, they have submitted their own planning application to Lewes and Wealden district councils.
It outlines how increasing the height of the river banks by just 1ft would preserve the valley for another 50 years.
Mr Newton, whose firm Bloomsbury publishes the Harry Potter books, hopes by getting in first they will put a stop to the agency's scheme, which includes removing some of the existing flood defences.
He owns one of the coastguard cottages at the sea end of the valley and says such a move could threaten his holiday home.
He and other campaigners, including town planner Alan Edgar, say their solution is gentle and non-destructive.
They say the agency's plan would damage a fragile local economy, particularly tourism, by destroying public footpaths and replacing the well-loved pastoral scene with mud flats.
They fear more erosion would be caused and reject the agency's claims it would benefit the wildlife habitat.
Mr Newton said: "Wildlife cleansing is not an option.
"The agency claims other species will be attracted but what about those we have now? What about their rights, their habitat, their environment?"
Mr Edgar said: "The nice thing about our plan is nothing will change, no species will be threatened and even the construction process will be small-scale and low-key.
"Environment Agency press releases claim the existing flood banks 'are beyond their useful life' and millions are needed to reinforce them with steel and concrete walls.
"This is just bureaucratic terrorism to frighten us into thinking the only alternative to its plan is to have concrete scars in this beautiful valley."
Peter Midgely, the Environment Agency's regional manager for Sussex, said: "Obviously anyone is within their rights to put in a planning application but I can't see how people can put in a planning application for land they do not own.
"We are the managers of the river bank and we feel the time has come to stop spending money on working against nature and work with it.
"We will still retain the meanders. Our plans will neither hasten nor lengthen the life of the cottages.
"Everyone wants to see a natural and beautiful valley."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article