Will development at Hampton Green increase the chance of flooding?
The Environment Agency works very closely with local planning authorities to ensure that any developments in Northampton have a good standard of flood defence and that they do not affect existing communities.
Our proposed site lies in Flood Zone 1, meaning that there is less than a 1 in 1,000 annual chance of river or sea flooding. Our studies show that while the site attracts some low risk surface water accumulations, these are unlikely to pose any threat to development and can be easily managed in the design of the development.
The drainage strategy we’ve developed focuses on providing effective drainage and management of surface water to ensure the site won’t flood while also reducing the amount of water leaving the site as run-off into the surrounding area. Methods we’re proposing include:
- Using attenuation methods including permeable paving and natural ditches to capture rainwater and encourage sustainable drainage by directing all surface water to two new attenuation ponds with storage capacity of around 6,900m3 which will be located on site.
- Carefully controlling any water that does leave the site by discharging it into local sewers and ditches.
What is being done to sustain and preserve the site's ecology?
The enhancement of existing ecology is central to our proposals for Hampton Green and has been given full consideration in the development of our masterplan.
The majority of the hedgerow and hedgerow trees around the site boundaries will be retained to maintain wildlife corridors and biodiversity across the site. This will be complemented by new tree planting across the site, including along the primary access route to create an avenue, as well as the development of a green buffer zone along the eastern edge of the site to soften the transition between the proposed development and the surrounding countryside.
We have carried out ecological studies to survey hedgerows, badgers, bats, dormice, birds, reptiles and great crested newts. There are no statutory wildlife site designations overlapping with the development, but we have identified an indirect impact from increased recreational use of the Upper Nene Valley Gravel Pits special protection area, specifically Clifford Hill Washlands. We have consulted with Natural England (the statutory authority) and we shall mitigate this potential impact by providing open space in the development, (including dog walking routes), promoting walking routes in the Brackmills Country Park and contributing to access management for the Washlands.
Are you aware that site was previously used for landfill?
Yes, the southern part of the Hampton Green site (land between Newport Pagnell Road and The Green) is classified as historic landfill and was licensed to accept inert waste.
To ensure the land is suitable for building homes we have carried out extensive intrusive ground investigation works across the whole site in consultation with Environmental Health Officers at South Northamptonshire Council and Northampton Borough Council.
The findings from this work identified areas of landfill across the southern part of the site and some associated small pockets of contamination, known as ‘hotspots’. With the exception of these hotspots, the remainder of the site registered normal readings for residential land use.
None of the contaminants recorded at hotspots exceeds the relevant thresholds for residential land and would not pose a risk to future residents of our proposed development. However we are developing a remediation strategy as part of our application which sets out how we will clear away these areas of contamination ahead of any homes being built. The likely strategy will involve removal of material to suitable landfill sites or capping with clean soil.