Nature-Based Water Solutions at Anglian Water
Nature-Based Water Solutions at Anglian Water
TL;DR: Anglian Water is scaling treatment wetlands and retrofitted Sustainable Drainage Systems to manage stormwater, cut storm overflow spills, and improve river and bathing water quality. These nature-based assets sit alongside grey networks to deliver Biodiversity Net Gain and climate-resilient urban regeneration. As urban populations grow and storms intensify, traditional concrete pipes and tanks are reaching their practical and financial limits. Utilities can no longer rely on ever-larger underground storage to manage flood risk and meet environmental expectations. Anglian Water is instead treating nature as core infrastructure, integrating wetlands and green streets into its coastal catchments to keep rainfall out of sewers and restore river systems.
System Logic for Green-Grey Water Infrastructure
The system logic behind Anglian Water’s strategy is to treat rainfall as a local landscape asset rather than a burden on buried sewers. Constructed wetlands and Sustainable Drainage Systems slow, store, and filter water close to where it falls, reducing peak flows into combined networks and providing a secondary, low-energy treatment step that removes ammonia, phosphate, and suspended solids before water re-enters rivers.
This matters because existing combined sewer systems were not designed for today’s climate-driven rainfall intensities or urban growth, driving storm overflows that damage river health and public confidence. By intercepting surface water in streets, parks, and brownfield sites, SuDS schemes in coastal towns such as Southend, Caister, and Great Yarmouth can cut spill frequency while delivering visible green spaces, helping align flood risk management with regeneration and health priorities.
Governance relies on the Advanced WINEP framework and Get River Positive commitments, which set expectations for reducing storm spills, protecting chalk streams, and delivering Biodiversity Net Gain. Nature-based schemes must evidence both hydraulic and ecological performance, and business plans increasingly treat wetlands and SuDS as core enhancement options alongside, or in place of, chemical dosing and carbon-intensive tertiary treatment.
Green Regeneration at Anglian Water
At Ingoldisthorpe, Anglian Water and Norfolk Rivers Trust have created an integrated constructed wetland that takes treated effluent from the water recycling centre through four shallow, vegetated cells planted with around 25,000 native wetland plants. Early monitoring showed mean nitrate and phosphate concentrations reduced by roughly 30%, with nutrient loading to the River Ingol cut by around 70%, while the site functions as a low-carbon extension to the existing works and a new wildlife habitat.
The Urban Regeneration Programme scales this logic across urban, coastal catchments, with Anglian Water planning £160 million of surface water management schemes that install SuDS and green infrastructure to remove runoff from combined sewers. These schemes, delivered with local councils and partners, create green and blue corridors, reduce flood risk, and improve bathing water quality, while a wider wetlands programme aims to deliver more than 20 additional treatment wetlands across the region by the end of the decade.
Anglian Water’s Urban Regeneration Programme is investing £160 million in nature-based surface water schemes across coastal urban catchments to remove rainwater from combined sewers and reduce storm overflow spills.
Take-Out
Anglian Water’s wetlands and SuDS portfolio shows how utilities can treat nature as core infrastructure, using catchment-scale design to relieve pressure on ageing sewers while improving biodiversity and public realm. For other cities, the key insight is that green-grey hybrids can achieve regulatory spill reductions and ecological outcomes more efficiently than solely expanding underground concrete assets.
Expert Follow-Up Questions
How does the Ingoldisthorpe treatment wetland actually work?
The Ingoldisthorpe wetland receives treated effluent from the water recycling centre into a series of shallow, interconnected ponds planted with native wetland vegetation such as iris, sedges, and watercress. As water passes through each cell, plants and microbial biofilms strip out remaining nutrients and solids, enabling further reductions in ammonia and phosphate loads before discharge to the River Ingol.
What benefits do SuDS schemes bring beyond flood management?
SuDS schemes in Anglian Water’s coastal catchments are designed to intercept and store surface water in rain gardens, permeable streets, and green spaces, reducing inflows to combined sewers and the frequency of storm overflow spills. At the same time, these interventions create cooler, greener streets, improve urban biodiversity, and support regeneration objectives by delivering new public spaces and improving the visual quality of town centres.
How is Biodiversity Net Gain achieved in these projects?
Treatment wetlands and SuDS are designed with native planting palettes and habitat structures that increase species richness compared with the pre-scheme baseline, helping to deliver Biodiversity Net Gain across schemes. Monitoring at sites like Ingoldisthorpe shows wetlands supporting wetland plants, invertebrates, and birdlife, while urban SuDS schemes create linked green corridors that amplify ecological benefits beyond individual assets.
How do nature-based solutions compare with traditional tertiary treatment?
Traditional tertiary treatment often relies on energy-intensive processes and chemical dosing to remove nutrients, whereas wetlands use plant and microbial processes with minimal operational energy input. While constructed wetlands require land and careful design, they can deliver comparable or better nutrient reductions with lower operational carbon, alongside co-benefits in biodiversity, amenity, and carbon sequestration.
What are the main risks and constraints when scaling wetlands and SuDS?
Key constraints include land availability, integration with existing urban plans, and the need for long-term maintenance responsibilities to be clearly allocated between utilities and local authorities. Hydrological and water quality performance must be robustly modelled and monitored to satisfy regulators, while business plans must account for lifecycle benefits that extend beyond traditional cost and compliance metrics.
Deep Dive: Water Utility of the Future – Anglian Water
Explore Anglian Water’s full nature-based portfolio, including site-level design for wetlands and SuDS, funding routes, and how green-grey hybrids are being integrated into long-term drainage and wastewater management plans.
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