Plans to build 2,000 homes in a flood risk area near the River Severn are “crazy” and should be revised, campaigners have said.
Outline permission has been granted for land between Innsworth and Twigworth in Gloucester.
Chris Witts, of Severn and Avon Valley Combined Flood Group, said developers should cover insurance costs.
Developers Bovis Homes and Taylor Wimpey said detailed flood mitigation and drainage measures were in place.
Although the land is not on a flood plain, it flooded in 2007 and is currently waterlogged after recent heavy rain.
Hatherley Brook runs through the site and local residents are concerned the development would put extra strain on the watercourse.
Mr Witts, who has also published several books on the Severn, said: “I would say a developer has to stand a 10-year insurance policy on each property.
“If they’re sure the property is not going to flood, they should stand the cost.
“I know from experience that land is heavily waterlogged and to build on it I just think is crazy.”
Twigworth parish councillor Graham Bocking said the plans needed to be “radically revised to correct the flood management proposals and minimise the flood risk which so many of us have concerns over”.
However, the Environment Agency and Tewkesbury Borough Council have approved the flood mitigation methods associated with the application.
Nick Green, from the agency, said: “Constructing flood storage areas can divert water away from the development and hold it and release it slowly as weather improves.”
A Bovis Homes spokesman said: “The site’s drainage strategy and mitigation measures have been scrutinised by the council in consultation with the EA, the lead local flood authority and other statutory consultees responsible for ensuring the site, and its surrounding area, are appropriately protected.”
A spokeswoman for Taylor Wimpey said when consent was granted “careful consideration was given to the suitability of the site, and we can confirm it has an approved detailed drainage strategy in place”.