Guidance

Importance of flood investigations

Published 16 April 2025

Applies to England

© Crown copyright 2025

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This publication is available at https://www.gov.uk/government/publications/investigating-a-flood-guidance-for-lead-local-flood-authorities/importance-of-flood-investigations

Flood investigations are a factual account of a flood event. They form an important evidence base, documenting where and when flooding has occurred from all sources.

Carrying out a flood investigation is beneficial as it can also contribute to wider flood risk management activities.

Engage with flooded communities

Conducting a flood investigation provides a unique opportunity to build and develop partnerships between risk management authorities (RMAs) and flooded communities by:

  • listening to communities’ experiences of flooding
  • gathering data and anecdotal evidence
  • understanding flood preparedness
  • co-developing recommendations

Better understand flood risk

Information and data gathered for flood investigations can help lead local flood authorities (LLFAs), and other RMAs, to:

  • identify and define new areas of flood risk and critical flood risk assets
  • understand the scale and consequences of different sources of flooding
  • understand potential solutions to flood risks
  • understand asset performance
  • improve input data and validate modelled assessments of flood risk both locally and nationally
  • understand trends and patterns in flood events
  • update flood warning areas and thresholds
  • update emergency plans

Support the case for investment

Flood investigations and reports provide a public record of flooding and its impacts. While it is not a complete record of all flooding, it does provide evidence to support:

  • investment in new technical studies
  • the strategic case for flood and coastal erosion risk management grant in aid applications
  • wider government funding applications
  • asset and maintenance improvements
  • partnership funding from more than one RMA to develop integrated solutions to risk from combined sources or across administrative boundaries
  • generation of non-public contributions to flood risk management schemes

Flood risk and planning strategy

Recommendations from flood investigations should:

  • shape local flood risk management strategies and action plans and help with prioritisation of resources
  • inform investment plans for all RMAs
  • help local authorities make risk-based decisions about the location of development
  • increase understanding of the roles and responsibilities of RMAs and riparian owners

A flexible but consistent approach to flood investigations will allow data and information to be collected across England. This will make it easier to understand and analyse national trends and general lessons.

The guidance will improve understanding of different sources of flooding. It will also support flood risk policy development, strategic decision-making and the development of funding programmes.

The Environment Agency is exploring how it could use information it receives from LLFAs to identify any national trends.

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