Southern Water project unlocked with off-site BNG
Client: Southern Water
Sector: Utilities
Region: London & South East
LPA: Winchester City Council & Hampshire County Council
NCA: South Hampshire Lowlands
Habitat Bank: Witchampton, Dorset
Biodiversity Units: Grassland
To help meet their Biodiversity Net Gain (BNG) condition for an essential wastewater treatment works project in Hampshire, Southern Water reached out to Environment Bank. We supplied off-site Biodiversity Units and provided expert BNG support. With this help, planning permission was granted, and work could commence.
About the development project
Southern Water planned to install a stormwater Motor Control Centre (MCC) kiosk at the existing Wickham Wastewater Treatment Works in Fareham, Hampshire, containing the electrical control equipment needed to operate a new plant and stormwater storage tank.
This proposed development was required in connection with essential upgrade works underway to ensure compliance with an enhance discharge permit for phosphorus and iron set by the Environment Agency.
These upgrades would improve the quality of the wastewater released and help increase the stormwater retention capacity to benefit the local area.
With suitable space unavailable to meet their post-planning BNG condition entirely on-site, Southern Water needed to find an off-site provider that could supply Biodiversity Units for this project to proceed.
Effective off-site BNG provision is particularly essential for water treatment works as it enables important development to go ahead without the need for sterilising on-site land which could be of value to future operations – and Environment Bank were easily able to help.
We’re really grateful to the team at Environment Bank for making this process as straightforward as possible. They really know their stuff when it comes to BNG and now they’re helping support a number of our projects. I’d recommend Environment Bank to other water companies and utilities providers.
Cécile Stanford
Project Manager
Southern Water
Expert BNG solutions with an effective approach
After considering options from a number of BNG providers, Southern Water chose to work with Environment Bank who could provide BNG expertise alongside a ready supply of off-site Biodiversity Units from our BNG Habitat Banks.
Taking advantage of Environment Bank’s dedicated support, Southern Water were able to submit their planning documents with a clear strategy for BNG delivery, including detailed information provided by us about the Habitat Bank chosen to supply off-site Biodiversity Units.
This clarity demonstrated to the local authority precisely how Southern Water would meet their post-planning BNG condition, and this helped them secure planning permission for the project.
Southern Water completed their purchase with Environment Bank at the end of March 2025. Within two weeks, their Biodiversity Units were officially allocated on the biodiversity gain sites register.
Environment Bank continues to support Southern Water with off-site BNG, including for upcoming development planned for water treatment works like Burham, Otterbourne, and Flexford Lane Sway.
Supporting large-scale nature recovery in the south of England
Biodiversity Units were readily available from one of our registered BNG sites in the south, Witchampton Habitat Bank, which is being carefully monitored and managed by our own team of qualified ecologists in collaboration with the local landowner.
Along with grassland, we’re also creating and enhancing habitats across almost ninety acres including lowland meadows, ditches, scrubland, hedgerows, and floodplain grazing marsh along the River Allen corridor – all carefully blended to support the wider landscape and build ecosystem connectivity.
We hope to see rare local wildlife increase in abundance across the site and expect that the improved soil health will help to reduce surface runoff and support natural flood mitigation.
A big thank you to Southern Water for working with us and we’re thrilled to have played a part in such an important project. We’re looking forward to providing BNG support and off-site Biodiversity Units for their future developments.
Nathan Jenkinson
Strategic Account Director
Environment Bank