Flood risk

Where this hits in the East

The East of England holds a large share of England's low-lying agricultural and coastal land. Brownfield in those places is often former riverside industry, port land, or plots in market towns that sit on the same floodplain as the fields around them.

Fenland's Level 1 SFRA (June 2022) is the clearest published local figure: approximately 67% of the district is Flood Zone 3. The same geography runs through King's Lynn, Great Yarmouth, the Broads authorities, and the Essex and Thames estuary coast.

Why a flooded plot drops out

• Zone 3b is not available for new dwellings.
• Zone 3a needs sequential and exception tests, raised floor levels, and safe access. Those works consume plot and add cost.
• Insurance and mortgage availability can fail even where policy allows a consent.
• Flood storage and sustainable drainage take land that a tight brownfield plot does not have. That is the same squeeze as biodiversity net gain.

How to read the map

The flood step removes permissioned sites in authorities with extensive Zone 3. It is the last screen on this map still drawn at authority level: the Environment Agency's flood-risk-zone dataset runs to about 2.7 GB, which is too large to intersect in this site's build, where the Green Belt and nutrient catchment layers are a few tens of megabytes and are tested point by point.

So read this colour as a region, not a plot. A site in Cambridge city centre is not in the same position as a site in Wisbech, and a dry street in Great Yarmouth is caught here alongside the quayside. For a named plot, the Environment Agency Flood Map for Planning is the test.