BUILDERS must revise plans for a controversial development after an environment watchdog raised flooding concerns.

Yuill Homes have been told to use up-to-date figures to calculate Croft House's flood risk from the River Tees after the Environment Agency objected to the development on the grounds they had used old data.

The developer already has outline planning permission to convert the 19th century house, in Hurworth Place, near Darlington, into flats and build 15 houses in its grounds. It is discussing details of the plans with Darlington Borough Council.

The Environment Agency formally objected to the detailed plans in a letter to the council on June 15.

It said the agency had carried out a new flood risk assessment in January 2008, but the detailed plans were based on a July 2007 report.

New figures upgraded the site from medium flooding risk to high fluvial flooding risk.

It said the developers' proposal to raise floor levels was not high enough.

They also had concerns about dry exit routes in the event of flooding, storage volume estimates and surface water drainage.

It said the developer must provide a new risk assessment report based on the new findings to protect the existing and proposed developments from flooding.

Residents, who had raised concerns the development would be partially built on a flood plain, have welcomed the news, which they were given at a meeting with council planners on Monday.

Susan Dell, who lives in nearby Tees View, said: "This was the best outcome we could have had.

"But we still don't want to see them build on a flood plain. We feel as though the whole balance of the area is just very delicate."

Nigel Bell, land and development director for Yuill Homes, said the company had a proven track record.

He said although they had permission for 19 properties, they wanted to build 12 houses and convert Croft House into two semi-detached properties.

"The site's drainage is being carefully designed in consultation with the Environment Agency and takes full consideration of the circumstances of the site and its wider setting," he added.

A council spokeswoman said they were reviewing the detailed application and awaiting further details from the developer following consultation with the Environment Agency.