Working with Natural Processes: The Evidence Behind Natural Flood Management

Following both the London and Leeds events, the CIWEM Working with Natural Processes: The Evidence Behind Natural Flood Management event is taking place in Edinburgh next week on Wednesday 14 March.

Steve Rose, Technical Director, will be presenting at the event which will further launch the Environment Agency’s ‘Working with Natural Processes (WWNP) Evidence Base’. This has been developed to help flood and coastal erosion risk management (FCERM) authorities understand, justify, develop and implement FCERM schemes with WWNP to reduce flood risk.

We have been heavily involved in the development of this evidence base which Steve will cover in his presentation.

Mapping Areas of Potential for Working with Natural Processes

A new set of strategic maps to help identify potential areas for WWNP across England have been developed. The maps signpost a range of measures for managing flood risk by protecting, restoring and emulating the natural regulating function of catchments and rivers. They include measures to reduce flood risk by storing water, slowing water, increasing flow connectivity between rivers and floodplains and increasing soil infiltration and storage.

The maps are entirely based on Open Data, and have been published on-line as a suite of nested interactive PDFs for strong accessibility. They are published with a user-guide and technical report, and form part of the wider WWNP Evidence Base which covers wider aspects of modelling, monitoring and assessing multiple benefits of a wide range of measures.

The maps highlight potential for WWNP measures based on national datasets including the Environment Agency maps showing the risk of flooding from rivers, sea and surface water. They have been used to target areas where rivers have become disconnected from floodplain, or areas of high flow accumulations where it would be effective to temporarily store and hold back water to reduce flood peaks further downstream. They introduce new science on characterising slowly permeable soils, based on geological datasets with support from the BGS, where tree-planting could increase hydrological losses and reduce surface runoff. The maps identify areas of potential for:

  • Floodplain Re-connection
  • Runoff Attenuation Features
  • Gully Blocking
  • Woodland planting covering:
    • Floodplain planting
    • Riparian planting
    • Planting on slowly permeable soils

A new woodland constraints dataset based on Open Data aims to help users further refine where there is potential. This includes roads and rail, urban areas, existing woodland, peat and waterbodies, which may restrict opportunities for some interventions (in particular woodland planting).

Introducing the Evidence Directory

Steve Rose will introduce the audience to the content of the WWNP Evidence Directory. The Evidence Directory synthesises and develops the findings from a comprehensive Literature Review about what is known and not known about the effectiveness of different WWNP measures, to reduce flood risk within catchment and coastal areas.

The various elements of the Evidence Directory will be described using extracts from the new publication which has been designed to provide the wider WWNP community with a practical and accessible information resource. This includes a library of case studies from across the UK that can be drawn upon when planning, exploring, designing and implementing new WWNP initiatives.

Want to know more?

Email Steve Rose for more information on his presentation, the maps and the evidence base. You can also visit our natural flood management web page for more information.



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