Version: 1.0.0 | Published: 21 May 2026 | Updated: 0 days ago
Flooding per LSOA in 2018
Dataset
Summary
Description:
This dataset provides flood risk information for England at the LSOA level for 2018. It includes whether each area is at risk of flooding and the surface area at risk within Flood Zone 3, or both Flood Zone 2 and Flood Zone 3. Flood zones are defined as follows: Flood Zone 2 – land with a 0.1% to 1% (1 in 100 to 1 in 1000) annual probability of river flooding, or 0.1% to 0.5% (1 in 200 to 1 in 1000) annual probability of sea flooding, including areas with accepted recorded flood outlines; Flood Zone 3 – areas with a 1% or greater (1 in 100) annual probability of river flooding, or 0.5% or greater (1 in 200) annual probability of sea flooding. The underlying data is provided as a Geodatabase (GDB), indicating areas at risk per LSOA. The dataset is published by the Environment Agency.
Contact Point:
Documentation
Documentation:
The dataset contains four flood-related variables for each LSOA in England: (1) Dummy_flooded – a binary indicator of whether the LSOA is at risk of flooding; (2) Flooded_area_km2_FZ2and3 – surface area (in km²) at risk within Flood Zone 2 and Flood Zone 3; (3) Flooded_area_km2_FZ3 – surface area (in km²) at risk within Flood Zone 3; (4) Ratio_flooded_total – proportion of the LSOA area at risk within Flood Zones 2 and 3. Geographic identifiers include the primary LSOA code (LSOA21CD), a UK-wide harmonised code (data_zone_code), the region name (LSOA21NM), the 'country' identifier, and total LSOA area (total_area_km2). This data is provided in two distinct formats: a CSV file, which contains the tabular data; and a GPKG file, a geospatial format that combines the tabular data with the LSOA-equivalent boundary geometries for spatial analysis.
Coverage
Spatial
Spatial Coverage:
England
Geographical Levels:
LSOA
Temporal
Start Date:
Annual: 01-01-2018:31-12-2018
Frequency:
Annual
Date of Latest Release:
21 May 2026
Date of First Release:
21 May 2026
Provenance
Origin
Purpose:
The flood zone data is provided by the Environment Agency and represents a
composite of national and local flood model outputs, recorded flood outlines,
and information from past flood events. These sources are combined using the
National Flood Risk Assessment (NaFRA2) system to generate the best-available
extents of land at risk of flooding. The Flood Zones are intended to support
planning applications and inform whether a Flood Risk Assessment (FRA) and the
sequential test may be required. Users should note that the Flood Zones indicate
general flood risk for an area of land and are not suitable for assessing flood
risk for individual properties, as property-specific details are not included.
Users are advised to confirm that the dataset is appropriate for their intended
use.
Source:
The underlying data source is the Environment Agency Flood Map for Planning – Flood Zones dataset, which provides information on the extent of land at present-day risk of flooding from rivers and the sea, excluding the benefits of flood defences. The dataset is described in: https://environment.data.gov.uk/dataset/04532375-a198-476e-985e-0579a0a11b47. Flood risk areas were classified according to Flood Zone 2 and Flood Zone 3 criteria. The LSOA-level aggregation was performed by the Imago Team by calculating the surface area at risk and deriving ratios relative to total area, producing variables for flood presence (dummy_flooded), flooded area in km² (flooded_area_km2_FZ3 and flooded_area_km2_FZ2and3), and proportional coverage of each LSOA. Flood zone thresholds follow the Environment Agency's standard Flood Map for Planning definitions. Flood Zone 2 captures land with a 0.1% to 1% annual probability of river flooding, or 0.1% to 0.5% annual probability of sea flooding — representing a medium probability of flooding. Flood Zone 3 captures land with a 1% or greater annual probability of river flooding, or 0.5% or greater annual probability of sea flooding — representing a high probability of flooding. These thresholds are established by the Environment Agency and are used to support planning applications and inform whether a Flood Risk Assessment and the sequential test may be required.
Collection Status:
1.0.0
Author 1
Name Organisation:
Imago: Data Service for Imagery
Family Name Person:
Elisabetta Pietrostefani, Martina Pardy
Access and Governance
Usage
Data Use Requirements:
None
Access
Access Rights:
CC-BY-4.0
Licence:
CC-BY-4.0
Format and Standards
Estimated Dataset Size:
CSV: 3.6 MB, GPKG: 43.3 MB
Vocabulary Encoding Scheme:
EPSG:27700, OSGB36/British National Grid