Barwood Planning Application Refused and Yet Another Setback for Banner Homes
January 21st, 2013
Earlier this month, King’s Sutton residents concerned about the risk of increased flooding from new building in the village threatened legal action against Thames Water. Coincidentally, the past week has seen reversals for both the developers hoping to build new housing estates on or near land in the village that’s prone to flooding.
On Thursday, South Northants Council threw out Barwood Homes’ application to build 35 houses on land to the north of Hampton Drive that had already been earmarked for a flood alleviation scheme. Problems are also piling up for Banner Homes’ proposed development on land between the village’s flood plain and Banbury Lane. First, Thames Water rejected the company’s plans for foul water drainage (sewerage) on the site (click here for the story). Now, in a letter to South Northants Council’s planning department, the Environment Agency has expressed its dissatisfaction with Banner Homes’ flood risk assessment. The agency says the flood risk assessment and microdrainage calculations proposed by the developer to address conditions 16 and 28 of its outline planning permission are not up to scratch for the following reasons:
“It is essential that surface water from this site is managed so as not to increase flood risk downstream. It must be robustly demonstrated that this development will not increase this risk, or the risk elsewhere.” However, the Environment Agency says “it is not clear from the information submitted that surface water discharge rates and volumes from the site will be limited to existing greenfield rates.” To satisfy the requirements of condition 16, the Environment Agency says it “would wish to see clear evidence that surface water discharge from the site is not being increased” and also needs to see a final drainage plan showing the proposed system. However, the only drainage plan in Banner Home’s flood risk assessment is a preliminary design.
The Environment Agency has expressed concern at Banner Homes’ proposed widening of the stream at the point of surface water discharge. “Widening of the stream,” it says, “should not be considered a suitable method of attenuating surface water from the site. It would not be effective surface water storage, as the additional volume created would be filled by water from the stream before it would be utilised by the site’s drainage system. The required surface water storage must be provided within the on-site drainage system.”
The Environment Agency says that widening the stream at a high level, leaving a clearly defined low flow channel between two culverted sections, could provide some additional flood storage. “However,” it adds, “widening the entire stream has the potential to reduce in channel flow velocities, which is likely to lead to siltation of the channel, increasing flood risk and the need for maintenance. Therefore, details of any works should be discussed and agreed with the Lead Local Flood Authority, in this instance Northamptonshire County Council.”
In order to be able to satisfy the requirements of condition 16, the Environment Agency requires the following:
A final drainage layout plan, including means of discharge flow control.
A clear explanation of the existing and proposed surface water discharge rates and volumes from the site.
Calculations demonstrating that the proposed drainage system will achieve these rates and volumes without creating a flood risk on site.
Confirmation that stream widening is not required to attenuate surface water flows from the site and that any widening will be discussed and agreed with Northamptonshire County Council.
The Environment Agency has reviewed the information submitted in support of condition 16 and 25, foul drainage, and notes that Thames Water is not satisfied with the submitted foul drainage provision. The agency therefore says it wishes “to be consulted on any subsequent foul drainage solutions in relation to these conditions.”