Video report by ITV Meridian's Tony Green
Dozens of people in beachfront homes in east Kent say coastal erosion has undermined vital flood defences.
They say they also fear plans for large-scale dredging of the Goodwin Sands could now cause disastrous flooding of Kingsdown near Deal.
Coastal defences try to keep the sea back, but storms can sweep away shingle overnight, leaving homes vulnerable.
The Goodwin Sands serve as a natural sea defence. But Campaigners trying to protect them are concerned no one really knows what will happen once the port of Dover starts dredging there.
Joanna Thomson from the group Goodwin Sands SOS says: "They [the council] are making efforts and the residents are really appreciative of what they're doing. But what they're not doing is working out what might happen if there is dredging out on the Goodwin Sands. What the real problem is they're wave modelling and we have no faith in it. They took data from Deal Pier in 2006. So it's insufficient and it doesn't give you the whole picture of what's going on out on the Goodwin Sands and it's now 14 years out of date."
Resident Hugh Mitchell has been living in the area for 23 years and has seen changes. He says: "We used to have a large collection of shingle outside our house and since the groins came in we've lost about 30m of it. With the sea levels rising and these unpredictable tides, I think we could well see the loss of these houses."
A spokesman for the Port of Dover said that the licence to dredge the Goodwin Sands came with a number of conditions, all designed to protect the environment. They say when dredging begins they will work with experts and stakeholders to make sure all of those conditions are fully met.
In the meantime, Dover Council says it will continue with a beach management plan, with more beach replenishment in the next few months.