Evaluation of Technical Advice Note (TAN) 15: Development and Flood Risk

Welsh Government has just published a report prepared by JBA that provides independent evidence regarding the performance of TAN 15 and makes recommendations for future updates.  The existing version of TAN 15 was ground breaking when it was first published in 2004.  The TAN introduced flood zones, focussed on appropriate consideration the magnitude of the hazards as related to the consequences of flooding within an overarching framework that emphasised the necessity to adopt a precautionary approach.  Subsequent technical advances and policy refinements, such as the enhancement in the data and technical quality of flood modelling, the need to evaluate and identify risk from all sources, flood resilience and resistance and roles and responsibilities made it appropriate to review the approach set out in TAN 15 and identify adjustments that should be made.

The review performed by JBA identified the following key recommendations:

  • TAN 15 should move to a fully risk-based approach and the precautionary framework should be discontinued to reflect the reduced uncertainty in flood risk mapping evidence now available.
  • The risk-based approach should encompass all sources of flood risk and most importantly capture the awareness of surface water flood flooding, as experienced in 2007.
  • To support the changes there should be a complete review of the Development Advice Maps (DAM) and harmonisation with mapping prepared by NRW.
  • There should be a strong presumption against highly vulnerable development in areas of greatest flood risk.
  • There must be increased focus on the risk assessment during the allocation land for inclusion in Local Development Plans supported by the inclusion of clear guidance on the preparation of Strategic Flood Consequence Assessments

In all the JBA review included 14 recommendations that were supported by evidence drawn from workshops, analysis of existing documents, interviews and case studies.   We hope that the review (found HERE) will be the platform for future work to amend the TAN and keep Wales at the forefront of development and flood risk policy.

 Want to know more?

If you wish to discuss JBA’s report or our flood risk expertise in Wales, please contact George Baker at our Newport office.



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