River embankments in Wainfleet were not given adequate protection against flooding in the town last year, an investigation has found.
Lincolnshire County Council and the Environment Agency have been recommended to find funding to implement new mitigation measures for the town, including replacing the existing embankments.
An independent review into the floods which devastated the town last summer found that "significant rainfall" caused a breach in the relief channel bank and "eroded away until insufficient support remained".
Councillor Colin Davie, executive member for economy and place at the county council, said the report was the "start of a process" and that an action plan for future events needed to be devised for Wainfleet.
Almost 600 properties were evacuated when the River Steeping in the town burst its banks on June 12, 2019, leaving around 1,000 people out of their homes.
Lincolnshire County Council, the lead local flood authority, commissioned Norfolk County Council to carry out an independent investigation into the cause of the floods.
The report made a number of recommendations including monitoring silt levels, replacing existing embankments and developing an emergency plan for Wainfleet and the surrounding villages.
It found that "significant rainfall" caused an overflow of the river bank and a breach was formed as water flowed down the rear side of the bank.
Levels of silt, damage to the river bank by cattle and water levels in foul drainage systems could also have contributed to the floods, the report said.
The investigation found that the embankments built on the relief channel, which date back to the 1960s, did not offer sufficient protection of a new defence.
It said: "The embankments alongside the relief channel, built after the flood event of 1968, are constructed from the arisings excavated in constructing the relief channel.
"They do not afford the protection of a newly constructed flood defence."
Councillor Davie said it was now the job of the local authority to ensure that the town is "mitigated" from any future flooding.
"This is the beginning of the process," he said. "There will need to be an action plan where all the partners agree on actions to mitigate any future events.
"We have to ensure that we give the people of Wainfleet the highest level of protection possible. It's our role to ensure that everybody is working towards the same goal."
Meanwhile, the Environment Agency has been recommended to replace the embankments and consider the "longer term standard of protection" in the town.
Morgan Wray, flood risk manager at the Environment Agency, said the organisation will review the findings of the report.
"We well know the heartbreak, devastation and disruption faced by communities when flooding hits," he said.
"That's why we have been, and will continue to, work hand-in-glove with our partners including the county council, other local authorities and drainage boards to support those affected, and reduce the risk as much as possible.
"Together, we will be reviewing this report and carefully considering its recommendations to make sure we are doing all we can to protect local people, homes and businesses."
An equivalent of around two months of rainfall fell in two days in the town, leaving around 1,000 people out of their homes.
Boston and Skegness MP Matt Warman apologised to residents at a local meeting and said "Government exists to prevent the kind of flooding we saw".
Tara Elizabeth and Ashley Dolman, who live on Matt Pit Court in the village, said they felt "helpless" when the water began to rise.
Mr Dolman said the floods "absolutely devastated" his family and called on officials to ensure that it "will never happen again".