The Ipswich Strategic Flood Risk Assessment 2020 comprises a main report and appendices which refer to potential sources of flooding considered likely to affect Ipswich. Ipswich Borough Council's new Level 2 Strategic Flood Risk Assessment was published in October 2020. This supersedes the Level 2 SFRA prepared in 2011. The Ipswich Strategic Flood Risk Assessment 2020 can be downloaded below.
The Development and Flood Risk Supplementary Planning Document ('SPD') was updated in July 2022 to reflect the new Strategic Flood Risk Assessment 2020. The Development and Flood Risk SPD 2022 is available to view here.
Since the Ipswich Strategic Flood Risk Assessment (SFRA) was published in October 2020, there have been data and guidance changes at a national level. These are listed below, and their local implications are examined.
In July 2021, the Environment Agency updated the climate change allowances that should be applied to peak river flows. For the River Gipping, the climate change allowances that need to be considered by the local planning authority have reduced slightly. As a result, there are sections of the SFRA Report that are now out of date, and assessments made in the SFRA that are more conservative than they need to be to comply with national planning policy. The updated climate change allowances will be reflected in the next review of the SFRA. In the meantime, applicants are directed to the allowances published nationally https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances and should note that the SFRA represents a more cautious position.
In May 2022, the guidance was also updated with peak rainfall allowances. The allowances are provided by management catchments instead of at a national scale (for England). Peak rainfall allowances are provided for 1% annual exceedance probability (AEP) events and for 3.3% AEP events, and for 2 epochs rather than 3. The guidance on how to apply peak rainfall allowances has changed, using the central allowance for development with a lifetime up to 2100 and the upper end allowance for development with a lifetime from 2100 to 2125. The updated peak rainfall allowances will be reflected in the next review of the SFRA. In the meantime, applicants are directed to the allowances published nationally Climate change allowances for peak rainfall in England (data.gov.uk) .
In August 2022, the Government published updated Planning Practice Guidance on Flood Risk and Coastal Change. Applicants will need to check compliance with the National Planning Policy Framework and Planning Practice Guidance in preparing a site-based Flood Risk Assessment or Drainage Strategy. The Council will update the SFRA and Development and Flood Risk Supplementary Planning Document to reflect the new information in due course.
Other useful documents about drainage in Ipswich can be found here https://www.ipswich.gov.uk/content/drainage-engineering
The Strategic Flood Risk Assessment informed the production of the Development and Flood Risk Supplementary Planning Document ('SPD') in 2013 (and updated in 2016) which provided specific guidance to developers including a framework of requirements for "safe" development in the flood plain. The 2022 Development and Flood Risk SPD (see above) supersedes the earlier Development and Flood Risk versions.
You can download the superseded 2011 SFRA and its appendices in pdf format below:
Ipswich Borough Council,
Planning Policy,
3W Grafton House,
15-17 Russell Road,
Ipswich,
IP1 2DE
01473 432019
