New report shows flood risk at large homes site

GREEN roofs to retain water will be needed on some properties if a major housing scheme around Eastergate goes ahead.

The flood prevention measure is just one of the ways in which the flooding risks of the site for the possible 2,000-homes scheme can be countered.

Arun District Council members met last night (May 29) to decide if the major development – intended to be in a garden-city style – should be included in the latest version of its draft local plan.

As reported, they had rejected the suggested 580 homes a year in favour of 425 homes annually, plus 30 council houses.

If they stick with the lower target, it places a big doubt on the need for the large scheme in the Eastergate, Barnham and Westergate area.

A report by consultants Parsons Brinckerhoff to the council’s community infrastructure levy sub-committee last week showed the work which would be required to lessen the impact of flooding if the homes did go ahead.

The report, which was accepted by the sub-committee members, says: “The area is prone to flooding due to surface water run-off combined with watercourse blockages and a high water table.

“The suitability of this area for 2,000 dwellings should be informed by any findings of the surface water management plan which is being undertaken by Southern Water and West Sussex County Council.

“This project is at an early stage but will look at the existing problem and suggest ways of managing the existing risk.”

A surface water and wastewater drainage strategy produced for the landowners had set out the infrastructure needed to make the site viable.

This states the requirement of any developers to create a sustainable drainage system.

Included in the system will be green roofs where appropriate, rainwater harvesting, balancing ponds with restricted discharges and flood routing to manage run-off from severe storms.

The report says the system will ‘accommodate the increase in surface water run-off on site through the construction of ponds to contain water at times of high and intense rainfall and to then regulate the flow into existing water courses’.

“The sustainable drainage system will be critical to facilitating development at the site but, following comments from land drainage engineers, it is not expected this will prove be a constraint to development providing the Environment Agency, Arun, WSCC and Southern Water are fully engaged and working with developers as 
plans progress.”

Arun’s drainage engineers also highlighted, the report says, connections to existing water courses may be required from the housing to create a need for off-site improvement to the existing land drainage system.

The report states the Environment Agency is separately looking at the Aldingbourne and Barnham Rife area to enable flood risk to be better managed.