What Are Strategic Flood Risk Assessments (SFRAs)?

Origins and Policy Context

The requirement for SFRAs arose from increasing concern over the vulnerability of new development to flooding — particularly following significant flood events in the early 2000s. In 2006, Planning Policy Statement 25: Development and Flood Risk (PPS25) formally introduced the need for Local Planning Authorities to produce SFRAs as a way of integrating flood risk into spatial planning.

PPS25 marked a shift from reactive flood defence towards proactive risk avoidance through land-use planning. It embedded the Sequential Test and Exception Test into plan-making and development management, with SFRAs providing the evidence base to apply these tests.

Today, the requirement is carried through in the National Planning Policy Framework (NPPF) (Section 14: Meeting the challenge of climate change, flooding and coastal change) and its associated Planning Practice Guidance (PPG). Paragraphs 159–169 of the NPPF are particularly relevant. Local Plans are expected to be informed by up-to-date SFRAs and to steer development away from areas at risk of flooding wherever possible.

Role in Local Plans and Spatial Strategy

SFRAs are a mandatory evidence base document in the preparation of a Local Plan. Their purpose in this context is twofold:

1. Supporting the Spatial Strategy

The SFRA provides the technical basis for determining where development should go in relation to flood risk. This includes identifying:

• Areas that are suitable for allocation with minimal flood risk.
• Locations that may be subject to the Sequential and/or Exception Tests.
• Strategic areas where flood risk mitigation, infrastructure improvements, or adaptation measures will be necessary.

2. Enabling the Sequential Test for Site Allocation

Every site considered for allocation in the Local Plan must be subject to the Sequential Test, which is applied at plan level rather than at the application stage. The SFRA supplies the mapped evidence to determine which sites are sequentially preferable, based on their flood risk classification (including the effects of climate change).

Where sites in higher-risk areas are required to meet housing or employment needs — particularly in constrained urban authorities — the LPA may commission a Level 2 SFRA to provide the additional granularity needed to justify their inclusion in the plan.

Level 1 vs Level 2 SFRAs

Two tiers of SFRA are recognised in national guidance:

The distinction is critical: Level 1 provides the strategic framework; Level 2 supports justification where risks cannot be wholly avoided.

Technical Content and Data Sources

A well-prepared SFRA is a composite document, drawing on a range of datasets and models. These typically include:

• Environment Agency Flood Map for Planning (Rivers and Sea)
• Risk of Flooding from Surface Water maps
• Groundwater flood susceptibility maps
• Historic flood records and incident reports
• Climate change allowances (for fluvial flows and rainfall intensity)
• Flood defence asset data and residual risk analysis (e.g. breach modelling)

The technical sophistication varies depending on the level of assessment and availability of local modelling data. Increasingly, SFRAs are expected to align with Flood Risk Management Plans (FRMPs) and incorporate adaptive planning principles consistent with the EA’s Flood and Coastal Erosion Risk Management Strategy.

Implications for Land Promotion and Development Strategy

For developers and land promoters, SFRAs are not just background reading — they are active gatekeepers in the plan-making process. Their implications include:

• Site promotion: Sites in Flood Zones 2 and 3 will typically be subject to scrutiny through the Sequential Test during the plan-making process. Early-stage understanding of SFRA findings is essential to assess suitability.
• Evidence submission: Promoters may need to submit supplementary flood risk evidence (such as Sequential Tests or site-specific flood modelling) to support allocations in marginal or higher-risk areas.
• Allocation viability: Where flood risk mitigation or infrastructure costs are identified through the SFRA, these may affect the viability of allocation or require masterplanning responses.
• Influencing spatial priorities: In some areas, updated SFRAs have led to a fundamental reshaping of preferred growth areas, especially where climate change projections show a step change in risk over the plan period.

Climate Resilience and the Role of SFRAs

One of the more recent evolutions in SFRA guidance is the expectation that they support long-term resilience. In line with national climate policy and the EA’s future flood risk scenarios, SFRAs are expected to:

• Apply uplifted climate change allowances, which vary by region and catchment sensitivity.
• Assess the functional floodplain (Zone 3b), which is expected to expand over time.
• Recommend adaptive approaches to design and land use — including development layout, floor levels, and integration of blue/green infrastructure.

This reflects a broader policy shift towards adaptive planning, whereby development is designed not only to be safe today, but to remain sustainable in the face of projected climate impacts to 2080 and beyond.

Conclusion

Strategic Flood Risk Assessments form a vital part of the evidence base for plan-making, providing the technical foundation to guide development away from areas at unacceptable risk and ensure that allocations are resilient to future change. Their role extends beyond a procedural requirement; they influence spatial strategy, viability, and the sustainability of long-term growth patterns.

As local authorities continue to update their plans in response to climate change and new national guidance, up-to-date SFRAs will be central to those processes. Developers and planning professionals should remain closely engaged with their evolution and treat them as critical documents for shaping site strategies, assessing risk, and informing representations throughout the Local Plan cycle.