The future of the Cuckmere Valley in East Sussex is under discussion with a first drop-in session being held for interested people to have their say.
A debate is taking place over how to manage flood risk in the future
An Environment Agency draft strategy suggests the area is allowed to go back to being a tidal estuary.
But some local councils argue that, rather than no further maintenance of existing defences, more should be built in order to keep the valley as it is.
Environment officers were on hand at Seven Sisters Country Park on Saturday.
'Have to change'
The Environment Agency's first drop-in session will be followed by two more at the park's visitor centre on 15 and 17 November, and also others at Alfriston War Memorial Hall on 9 October and Seaford Little Theatre on 20 October.
A public consultation on the flood risk proposals runs until 10 December.
The agency's Harvey Bradshaw said: "Climate change and sea level rise mean that the estuary is changing, and we will have to change how we manage flood risk here to adapt to this.
"If we continued to fight against nature we would have to put in larger structures - these would be environmentally damaging for the estuary and its wildlife, and visually unsightly.
"It would also be expensive and we cannot justify spending flood risk money here to protect a flood plain where no homes are at risk."