A £6 million project to raise a river's walls has been revealed as the centrepiece of a proposed flood defence for Lewes.
The flood-prone River Ouse would be channelled through the historic town between built-up walls and embankments.
Work could start this time next year if the scheme is approved.
In the longer term, a flood plain would be created on open farmland south of the A27 and north of Rodmell.
Town campaigners welcomed news that a plan was being put forward almost two years after the town was devastated by the most serious flooding since 1801.
But they voiced fears they were being presented with "a fait accompli" and urged the Environment Agency to give the public a say.
Hundreds were left homeless and homes and businesses faced a multi-million pound clean-up bill after floods in autumn 2000.
Residents were upset by the lack of action in the aftermath, becoming increasingly concerned the disaster could be repeated.
Since then, householders and businesses have faced increasing difficulty in securing insurance for their homes and properties.
A spokeswoman for the Environment Agency said: "Our flood defence team has taken a long time to consider all the options to find the best long term solution for the town.
"The recommended strategy for Lewes is to raise the walls through the town to reduce the risk of flooding.
"Flood storage provision for the Winterbourne Stream should be reviewed in conjunction with English Nature.
"We are also supporting any long-term redevelopment proposals over the next few decades that would lead to the widening of the river corridor.
"We are proposing a five- year programme of works but are setting out a strategy for the next 50 years."
The plan will be presented to the Sussex Flood Defence Committee on Wednesday. If they like it, the proposals will be presented to the Department of Environment, Food and Rural Affairs (DEFRA).
The estimated cost is about £6 million, with the bill split between the Environment Agency, the Government and the owners of the walls.
Peter Atkins, spokesman for Lewes Flood Action, said the group remained in the dark about the proposals.
He said: "We are glad there is some movement at last but we are alarmed that we still don't know any details.
"We need more than simply raising the walls. We understand there may be a system of allowing the water to spread out below the town and that would relieve the pressure.
"There is alarm the community is not being consulted adequately. We don't want to be presented with a fait accompli. We want a chance to discuss the proposals at a public meeting."
The Environment Agency said the plans would be in the public domain after next Wednesday's meeting, stressing they would not be finalised until their approval by DEFRA.
A spokeswoman said there would be exhibitions of the plans in August as well as a public meeting.
Peter Midgley, Environment Agency Area Manager for Sussex, said: "I can understand how anxious householders and property owners are to see work started. I have every sympathy with them.
"Many have suffered a terrible ordeal and their agony has been prolonged as they have waited for the strategy.
"However, some of the problems we are dealing with are highly complex and it is important that we make sure our plans can withstand the financial scrutiny of government before the work begins."
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