Southern Water £1.3bn SuDS framework: design and risk notes for project teams
Reviewed by Joe Ashwell

First reported on New Civil Engineer
30 Second Briefing
Southern Water has launched a £1.3bn framework tender for sustainable drainage and habitat restoration across its catchment, targeting large-scale SuDS retrofits, nature-based flood management and river corridor enhancement. The multi-year programme will call for design-and-build teams to deliver measures such as swales, wetlands, infiltration basins and floodplain reconnection to cut surface water inflows to sewers and reduce CSO spills. Contractors will need strong geotechnical, hydrological and ecological capability, with emphasis on whole-catchment modelling and long-term asset performance.
Technical Brief
- Framework value is £1.3bn, signalling multi-lot, multi-year procurement with substantial package sizes.
- Tender is framed as “comprehensive services”, implying scope from feasibility and modelling through to construction and aftercare.
- Habitat restoration wording suggests works beyond hydraulic function, including channel re-profiling and riparian planting.
- Procurement via a framework enables call-off for varied catchments, soil types and legacy sewer configurations.
Our Take
Within the several Environmental stories in our coverage, Southern Water is one of the few UK utilities scaling nature-based solutions through a multi-year framework rather than isolated schemes, which is likely to appeal to contractors with long-term ecological design and monitoring capability.
A framework of this scale in the Sustainability and Projects tags typically attracts large multidisciplinary civils contractors paired with niche habitat and drainage specialists, so bidders may need to assemble consortia to cover both heavy infrastructure and ecological restoration skillsets.
Given the £1.3bn framework value and the Contract Award focus, this procurement is likely to set benchmark commercial and technical standards for sustainable drainage in the UK water sector, which other regional water companies may reference in their own AMP-period tenders.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.


