Guidance

Local planning authorities: strategic flood risk assessment

How local planning authorities can complete a strategic flood risk assessment.

As a local planning authority, you need to carry out a strategic flood risk assessment (SFRA) to assess flood risk in your area, and the risks to and from surrounding areas.

If you’re a local planning authority and you need to review a planning applicant’s flood risk assessment, read the guide on reviewing flood risk assessments.

You’ll use the strategic flood risk assessment to support your local plan and to help make planning decisions. Those involved (‘qualifying bodies’) in neighbourhood planning will look at the information in the strategic flood risk assessment when considering whether neighbourhood planning areas may be appropriate for development. Planning applicants will refer to your strategic flood risk assessment when carrying out their site-specific flood risk assessment.

Which level of assessment to complete

There are 2 levels of strategic flood risk assessment. All local planning authorities need to carry out a level 1 assessment at least, and it may be necessary to expand the scope of this assessment to a more detailed level 2 assessment.

Contact the Environment Agency or your lead local flood authority if you’re not sure which assessment you should do.

Level 1 strategic flood risk assessment

You should provide enough detail in your level 1 assessment for the sequential test to be applied.

Your level 1 assessment must include maps showing the entire area your local planning authority covers. You can commission a flood consultancy firm to do this on your behalf.

These maps should show:

  • main rivers
  • any other rivers, streams and any other significant bodies of water
  • development sites that have been allocated in the local plan as well as sites under consideration for future allocation in the local plan
  • flood zones including the functional floodplain (land where water has to flow or be stored in times of flooding) if there is one
  • any land safeguarded from development that is required for current and future flood management

You should also include an assessment of flood risk in your area to and from surrounding areas in the same flood catchment. Consider in this assessment flooding from all sources (for example, surface water drains) not just the rivers and sea, and include an allowance for climate change. Also consider the impact (including cumulative impact) that land use changes and development will have on flood risk and the opportunities to reduce flood risk to existing communities and developments.

Your assessment should:

  • map areas at risk from other sources of flooding
  • list existing measures (for example, flood gates, flood defence assets) to manage flood risk – state where they are and what standard of flood protection they provide
  • list areas that are covered by flood warnings
  • map any area with critical drainage problems as notified by the Environment Agency
  • map areas that may need surface water management plans
  • map locations that may be vulnerable to an increased risk of flooding, such as from increased surface water run-off, if there’s additional development
  • refer to flood risk management actions identified in the local flood risk management plan, where applicable

Your assessment should also contain advice for applicants who are carrying out site-specific flood risk assessments. Make it clear what the requirements are in particular locations to assess and manage flood risk. You can provide advice on the use of sustainable drainage techniques in certain locations.

To help you compile your strategic flood risk assessment you can contact:

Level 2 strategic flood risk assessment

Where a level 2 assessment is required, your assessment should build on the information in the level 1 assessment and include enough information for the exception test to be applied. Where a level 2 SFRA is produced, you should also use this information to apply the sequential approach and the sequential test to identify sites with the lowest risk of flooding within flood zones 2 and 3.

Your level 2 assessment should assess the condition and location of existing flood defences. Speak to the people who operate and maintain it (for example your local authority, the Environment Agency or Internal Drainage Board.

You should also assess the risk of flood defences failing, for example could defences be breached or pumped assets fail. The likelihood of flood defences failing will change over time, for example because of limitations on maintenance funding and/or degradation. You should also consider what would happen if the flood defences failed. This should include an assessment of the extent, duration, velocity, depth and rate of onset of flooding, as well as identification of affected properties, infrastructure and communities.

Include an allowance for climate change as well as wave height and direction for assessments in coastal areas.

This assessment should form part of the evidence to inform planning decisions.

If there’s anything specific that planning applicants need to do to show their development meets the requirements of the exception test, where applicable, you also need to state this.

Published 1 July 2013
Last updated 28 February 2017 + show all updates
  1. Added content to sections: Level 1 and Level 2 strategic flood risk assessment. Change link for "These maps should show: •main rivers" to point to the Main River map
  2. First published.