Local information requirements: Flood Risk Assessment

Types of application that require this information:

• Any development proposals in High Flood Risk Zone (Zone 3)
• Any development proposals in Medium Flood Risk Zone (Zone 2)
• Any operational development of 1ha or above in Low Flood Risk Zone 1
• Development proposals on sites over 0.5 hectares in size located within ‘Critical Drainage Areas’

Details of what should be included:

Flood Risk Assessments should always be proportionate to the degree of flood risk in each case and appropriate to the scale, nature and location of the proposed development or change of use.

As a minimum it is suggested that developers/applicants should answer the following questions:

• What type of development is proposed and where will it be located? Include whether it is new development, an extension to existing development or change of use etc.
• What is its vulnerability classification? (see Table 2 of the NPPG on Flood Risk).
• What sources of flooding could affect the site?
• Which flood zone is the site within? (Check the Environment Agency Flood Map for Planning.
• For sites in Flood Zone 2 or 3, the depth of flooding predicted at the site.
• What does the Strategic Flood Risk Assessment (SFRA) show for this site?
• Does the development comply with the policies in Salford’s 2008 Flood Risk and Development Planning Guidance?

A more detailed study is likely to be required for any development in Flood Zone 2 or 3 which is for at least one dwelling or non-residential development of greater than 250 square metres floorspace. If a more detailed study is required, a typical Level 2 or Level 3 FRA could cover the following:

1. Development site and location:

• Location of development site
• Current use of the site

2. Development proposals:

• What development is proposed
• The vulnerability classification (see Table 2 of the NPPG on Flood Risk)
• Details of the development layout, referring to the relevant drawings (cross referring to the main application)

3. Sequential test

For Flood Zones 2 or 3 only – not necessary for developments wholly in Flood Zone 1. Also not necessary for certain minor developments (see paragraph 046 of the Flood Risk NPPG) or for change of use unless change of use to a highly vulnerable use such as a caravan site.

• Evidence that the Sequential Test has been applied in the selection of this site for the development type proposed, or reference to this if presented in other planning documents (for example the Local Plan)
• Explain why you consider the development cannot reasonably be located within an area with the lowest probability of flooding (flood zone 1); and, if your chosen site is within flood zone 3, explain why you consider the development cannot reasonably be located in flood zone 2
• Where appropriate, demonstrate how land uses most sensitive to flood damage have been placed in areas within the site that are at least risk of flooding (applying the Sequential Test at site level

4. Definition of the flood hazard including climate change

• All sources of flooding that could affect the site
• Identify sources, describe how flooding would occur, with reference to any historic records wherever these are available
• The flood zone the site is within
• Information from the SFRA covering the sit
• The probability of the site flooding taking account of the contents of the SFRA and of any further site-specific assessment
• The effects of climate change on flood risk for the lifetime of the development
• The expected depth and level for the design flood (generally in Salford this is a 1 in 100 year flood including climate change)
• Are properties expected to flood internally in the design flood or the extreme (1 in 1000 year flood) and to what depth

5. Flood risk management measures:

• How will the site be protected from flooding, including the potential impacts of climate change, over the development’s lifetime
• Demonstrate how the measures to protect the development from flooding will ensure that there will be no increased flood risk elsewhere

6. Residual risks:

• What flood-related risks will remain after measures to protect the site from flooding have been implemented.
• Who will manage the risks over the lifetime of the development.

7. Exception Test (if necessary – see paragraph 159 of NPPF)

• Would the proposed development provide wider sustainability benefits to the community? If so, could these benefits be considered to outweigh the flood risk to and from the proposed development?
• Will the proposed development remain safe over its lifetime without increasing flood risk elsewhere?
• Will it be possible for the development to reduce flood risk overall?