Planning and flood risk

How is flood risk considered in planning for future development?

The Government's National Planning Policy Framework (NPPF) requires local authorities to demonstrate the issue of flood risk has been considered as part of the planning process. It also requires that flood risk is managed in an effective and sustainable manner and where, as an exception, new development is necessary in flood risk areas, the policy aim is to make it safe without increasing flood risk elsewhere and wherever possible reduce flood risk. This process is referred to as the Flood Risk Management Hierarchy.

Flood Risk Management Hierarchy
Step 1AssessAppropriate flood risk assessment
Step 2AvoidApply the sequential approach
Step 3SubstituteApply the Sequential test at site level
Step 4Controle.g. SUDs, design, flood defences
Step 5Mitigatee.g. Flood resilient construction

Sequential test

The Sequential Test is a decision making tool designed to ensure that areas at little or no risk of flooding are developed in preference to areas of higher risk. The NPPF advises that 'the aim of the Sequential Test is to steer new development to areas with the lowest probability of flooding. Development should not be allocated or permitted if there are reasonably available sites appropriate for the proposed development in areas with a lower probability of flooding'.

A Strategic Flood Risk Assessment (SFRA) should provide the basis for applying the sequential test.

Exception test

The NPPF allows the application of the Exception Test where following application of the Sequential Test it is not possible, consistent with wider sustainability objectives, for development to be located in zones with a lower risk of flooding. The Exception Test therefore provides a method of managing flood risk while still allowing development to occur.

Further guidance on how planning applications will be considered in relation to flood risk issues and in particular the Sequential Test, Exception Test and Flood Risk Assessments (FRA) will be available to download from here shortly.

Strategic Flood Risk Assessment (SFRA)

A SFRA provides an overview of all sources of flood risk. This includes rivers, surface water, groundwater, large reservoirs, lakes and sewers.

At the sub-regional level, a Greater Manchester SFRA was completed in August 2008.

At the more local level, the Council in partnership with Oldham and Rochdale councils appointed JBA Consulting to undertake a Level 1 and Level 2 Strategic Flood Risk Assessment. The risk of flooding from rivers, surface water, sewers, groundwater, canals and reservoirs has been explored for Bury, Rochdale and Oldham as part of this Strategic Flood Risk Assessment.

Due to file sizes it has not been possible to publish all the SFRA maps on our website. You can view copies of the reports and associated maps at the Council's planning office or we can provide a CD at a cost of £20.

Surface Water Management Plan

Surface water is water collecting on the ground after heavy rain causing flooding to people, their properties and other infrastructure. A Surface Water Management Plan (SWMP) is a tool to identify areas more vulnerable to surface water flooding, and to identify measures to reduce the flooding, recognising that it is not possible to eliminate flooding altogether.

The Greater Manchester SWMP was completed in January 2013 and comprises two stages. Stage One considered Greater Manchester as a whole and Stage Two developed area specific SWMPs, one of which relates to Water Street in Radcliffe.

Stage One and Two provide:

  • A strategic overview of surface water flood risk in GM and the interrelationships between districts;
  • A more detailed assessment of surface water risk in Water Street;
  • Evidence to inform Bury's Local Flood Risk Management Strategy; and
  • Good practice guidance to inform future strategic, area or site based surface water management planning activities within the Borough.

Surface Water Management Plan documents are available to download below.

Emergency Planning Considerations

The Greater Manchester Civil Contingencies and Resilience Unit has prepared a guide on flood risk and emergency planning considerations when assessing relevant planning applications. This is available to download below.