The scale of public investment being directed at flood resilience is without precedent in the modern water sector. The government’s flood defence programme commits extensive multi-year capital to building new schemes, maintaining existing defences, and integrating surface water risk management into national planning frameworks. Ofwat’s Asset Management Period (AMP8), running from April 2025 to March 2030 and confirmed through the Price Review 24 process, allocates a large share of the approved capital programme to storm overflow reduction. The target, set out by the Department for Environment, Food and Rural Affairs (Defra), is to nearly halve the average number of spills per storm overflow by the end of the decade, against a 2021 baseline. For water utilities, local authorities, and drainage contractors, this investment cycle is the dominant procurement driver of the current period.
The Environment Agency added new Flood Map for Planning surface water layers in May 2026, incorporating climate change allowances for surface water flood extents modelled across the remainder of the century. This update means that sites previously screened out of surface water risk assessments now fall within mapped risk areas, elevating drainage design from a technical condition to a primary planning constraint. The December 2025 revision to the National Planning Policy Framework reinforced this shift, making surface water flood risk a factor in location and layout decisions rather than a detail to be resolved at the drainage design stage. For developers and local planning authorities, this change in mapping and policy has practical and immediate consequences for how planning applications are assessed and how drainage schemes are specified.
Nature-Based Approaches to Integrated Resilience
Nature-based solutions are increasingly embedded in the regulatory and commercial response to surface water risk. Sustainable drainage systems, green roofs, rain gardens, permeable paving, and constructed wetlands are being specified not simply as amenity features but as functional elements of a flood-resilience strategy, capable of attenuating runoff volumes and reducing the burden on combined-sewer infrastructure. Water UK has confirmed that AMP8 investment in storm overflow reduction includes nature-based methods alongside hard infrastructure, reflecting a shared view among water utilities, environmental consultants, and engineering firms that integrated approaches deliver superior outcomes at lower whole-life cost than conventional storage alone.
The challenge facing drainage professionals, local flood authorities, and developers is not a shortage of available techniques but the absence of a unified framework for integrating them across planning, procurement, and operational maintenance. Surface water mapping, hydraulic modelling, and catchment-wide intervention planning are all improving rapidly; the Environment Agency committed to standardising surface water modelling by the end of 2025, with updated data feeding national assessments from 2026 onwards. Translating that analytical capability into coordinated action across the fragmented network of water utilities, local authorities, and private developers remains the central institutional challenge of this period.
Urban Drainage UK 2027 convenes the senior professionals responsible for surface water management across water utilities, local authorities, and the development sector to examine where nature-based flood resilience is delivering measurable results, how the updated planning and mapping frameworks are reshaping drainage investment decisions, and what the AMP8 capital programme means in practice for the procurement and delivery pipeline across the UK.
