This Level 1 and Level 2 Strategic Flood Risk Assessment (SFRA) updates and replaces the 2009 SFRA. The 2015 study assesses flood risk from all types of flooding in the borough, taking into account climate change, in line with current national policy and guidance. The Level 2 SFRA assesses flood risk associated with a number of specified sites in more detail.
The purpose of the Strategic Flood Risk Assessment (SFRA) is to inform plan making and flood risk management in Welwyn Hatfield. A Level 1 SFRA was published in 2009. Information on flood risk in Welwyn Hatfield has evolved since publication of the council's 2009 SFRA, with the Environment Agency periodically updating their fluvial flood risk maps and producing new surface water flood maps. In order to maintain an up to date evidence base for the Local Plan and ensure the SFRA is consistent with new national legislation and policy on flood risk management, JBA Consulting Ltd were commissioned to update the existing Level 1 SFRA and produce a Level 2 SFRA assessment of specified sites. The latest edition of fluvial and surface water flood maps (from 2015) and latest information from other sources have been used to update the SFRA, resulting in some changes to our understanding of flood risk in Welwyn Hatfield since 2009. The 2015 SFRA has been signed off by the Environment Agency and Hertfordshire County Council as Lead Local Flood Authority.
Key outputs of the 2015 SFRA include a broad scale assessment of flood risk from various sources across Welwyn Hatfield, accounting for the impact of climate change; guidance on how flood risk may best be managed; screening of all Stage 2 SHLAA sites (as of August 2015) against fluvial and surface water flood risk; a more detailed Level 2 Assessment of flood risk associated with sites within Flood Zone 2 and/or 3 or those with an Ordinary Watercourse; and an assessment of the potential cumulative impact of development on flood risk in areas of the borough and potential cross-boundary issues posed by development proposals.
Information, guidance and recommendations from the 2015 SFRA will be used to appraise and test sites and aid preparation of the Local Plan, in an iterative process, by informing the following:
- Housing and Employment Land Availability Assessment (HELAA)
- Sustainability Appraisal (SA)
- Site Selection Document
- Flood Risk Sequential Test Document
- The preparation of strategic and development management policies that relate to flood risk and the water environment.
The SFRA was reported to the meeting of the Cabinet Housing and Planning Panel on 17 December 2015.
In February 2016, the Environment Agency published revised guidance on making allowances for climate change when modelling fluvial flood risk. In order to be consistent with this guidance, the Council and its consultants undertook an analysis of how the new guidance affected the results of the SFRA 2015. With the approval of the Environment Agency, certain sections of the SFRA were updated and the Council reissued the SFRA Main Report, Level 2 Summary Tables within Appendix A and Appendix D Climate Change Maps in June 2016. The reissued versions replace those published in December 2015.
The SFRA Main Report and Appendices, including the Level 2 site assessments, can be viewed below: