Flood Risk Updates in NPF4

What is NPF4

The National Planning Framework 4 (NPF4) is the successor to the Third National Planning Framework (NPF3) and represents the Scottish Government’s strategy for planning Scotland’s land over the next two decades.

It was adopted on February 13, 2023, and brings major changes to how Scotland’s land is used. The framework prioritizes protecting and restoring the natural environment, promoting active travel, and providing sustainable and affordable housing.

What Are the Changes to NPF4?

Following NPF4’s adoption on February 13, the Scottish Environment Protection Agency (SEPA) confirmed significant updates regarding the functional floodplain and developable areas across Scotland.

SEPA stated: “Under the new Fourth National Planning Framework (NPF4) which will be adopted on the 13th February 2023, flood risk areas (previously known as the functional floodplain), will require to include the appropriate allowance for climate change for the region.”

Previously, most new development was avoided within the functional floodplain (the 1 in 200-year baseline extent). Now, with the exception of “Most Vulnerable Use” designations, developments must be situated outside the Flood Risk Area — defined as the 1 in 200-year flood extent plus an appropriate climate change allowance.

This policy change affects all residential developments not yet submitted. The “Most Vulnerable” category (hospitals, schools, care homes, and holiday sites) must be assessed against the 1 in 1000-year flood plus climate change.

For developments in regions like Argyll and Tweed River Basin, an additional 59% peak flow allowance may be required beyond the 1 in 200-year flow estimate, potentially necessitating flood modelling revisions to establish new levels.

The policy took effect on February 13, 2023. Compensatory Storage Areas can still be incorporated to offset displaced flood volume.