Areas Benefiting from Flood Defences

Alternative Title

Dataset Language

This dataset shows those areas that benefit from the presence of defences in a 1 in 100 (1%) chance of flooding each year from rivers; or 1 in 200 (0.5 %) chance of flooding each year from the sea.
If the defences were not there, these areas would flood in a 1 in 100 (1%)/ 1 in 200 (0.5 %) or larger flooding incident. Note that we do not show all areas that benefit from all flood defences.
Some defences are designed to protect against a smaller flood with a higher chance of occurring in any year, for example a flood defence which protects against a 1 in 30 chance of flooding in any year.
Such a defence may be overtopped in a flood with a 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year, but the defence may still reduce the affected area or delay (rather than prevent) a flood, giving people more time to act and therefore reduce the consequences of flooding.
We do not always map areas that benefit from defences that offer a lower standard of protection. Other defences are designed to withstand a larger flood with a smaller chance of occurring in any year.
In this case, we show only the area that would have been affected in a flood with a 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year, even though further areas would benefit in the event of more severe flooding for example in a 1 in 1000 (0.1%) flood.
The rivers and sea criteria 1 in 100 (1%)/ 1 in 200 (0.5%) chance of occurring in any year aligns with Flood Zone 3 as described in the Planning Practice Guidance.
Topic Category

Keyword Value: Areas Flood Benefit Defences Environment Agency
Originating Controlled Vocabulary: GEMET - INSPIRE Spatial Data Themes (GEMET)
Originating Controlled Vocabulary Citation: 2008-01-01
Temporal Extent

from -2009-11 to -2021-05
Dataset Reference Date

Date: -2021-05
Date Type: revision

EA release the whole dataset quarterly but only update it in locations where new information is available
Hertfordshire County
Vertical Extent

Spatial Reference System

OSGB36 - National Grid of Great Britain
Spatial Resolution

Resource Locator

protocol: DSP:ESRI name: FloodMapForPlanningRiversAndSeaSpatialFloodDefences_Download description: Flood Map for Planning (Rivers and Sea) - Areas Benefiting from Defences Download
protocol: WMS name: FloodMapForPlanningRiversAndSeaSpatialFloodDefences_WMS description: Flood Map for Planning (Rivers and Sea) - Areas Benefiting from Defences WMS
protocol: WFS name: FloodMapForPlanningRiversAndSeaSpatialFloodDefences_WFS description: Flood Map for Planning (Rivers and Sea) - Areas Benefiting from Defences WFS
protocol: WWW:LINK-1.0-http--link name: Flood_Map_for_Planning_Rivers_and_Sea_Areas_Benefiting_from_Flood_Defences_ESRI_REST_Endpoint description: Flood Map for Planning (Rivers and Sea) - Areas Benefiting from Flood Defences - ESRI REST Endpoint
protocol: http:// name: DSP_CUSTOMER_FORUM description: Defra Data Services Platform Customer Forum

Layerfile for use by HCC internal staff: J:\Geodata\EnvAgncy\Flood_Map\AreasBenefitting.Lyr
ESRI/SDE, ESRI/Shapefile
Responsible Organisation

Environment Agency
Role: Resource Provider, Custodian, Owner, Distributor, Originator, Point of Contact, Processor, Publisher, Author.
Limitations on Public Access

no public access constraints to this data. Use of this data is subject to the licence identified. Open Government Licence
Use Constraints

Open Government Licence
This data is supplied without guarantee or any warranty as to the accuracy, currency or completeness, and is provided as is, excluding any warranties of any
kind, either express or implied, to the fullest extent permitted by law,including (but not limited to) satisfactory quality or fitness for a particular purpose.
Additional information

Resource Identifier


Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council
as regards interoperability of spatial data sets and services.
Re-designing HCC Data for INSPIRE not done
Equivalent scale

Bounding box
0.76, 0.22, 51.58, 52.10
Quality scope
Spatial representation type

Character encoding
Data quality
Maintenance information
maintenance and update frequency: Quarterly
update scope:feature
maintenance note: updates available quarterly from LINK />
Metadata update date
Metadata Language

Metadata Point of Contact

Environment Agency
Resource Type

6 Dataset
File Identifier
Hierarchy level name
Parent identifier
Metadata standard name

Metadata standard version
Review date
Name Long Name Description

OSGB36 National Grid Bounding Coordinates

West: 486000 East: 552000 North: 245000 South: 189000
More Information

Change History