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Metadata
- High level information
- Summary information
- Statistical quality information
- Weblinks
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- Open Data
Title
Properties at Risk of Flooding in WalesLast update
January 2017Next update
2019Publishing organisation
Welsh GovernmentSource 1
National Flood Risk Assessment data, Natural Resources WalesContact email
stats.environment@gov.walesDesignation
NoneLowest level of geographical disaggregation
Local authoritiesGeographical coverage
WalesLanguages covered
English onlyData licensing
You may use and re-use this data free of charge in any format or medium, under the terms of the Open Government License - see http://www.nationalarchives.gov.uk/doc/open-government-licenceGeneral description
The National Flood Risk Assessment (NaFRA) together with the National Property Dataset (NPD) are used to determine the number of properties (residential and non-residential) at risk of flooding from rivers and sea in Wales.Data collection and calculation
The chance of flooding is set out in four risk categories:High Risk; Greater than or equal to 1 in 30 (3.3%) chance in any given year
Medium Risk; Less than 1 in 30 (3.3%) but greater than or equal to 1 in 100 (1%) chance in any given year
Low Risk; Less than 1 in 100 (1%) but greater than or equal to 1 in 1,000 (0.1%) chance in any given year
Very Low Risk; Less than 1 in 1,000 (0.1%) chance in any given year
The NaFRA includes flooding from all rivers with a catchment size greater than 3 square kilometres, and all flooding from the sea (both along the open coast and tidal estuaries). Smaller rivers are included in the assessment where they fall within the area that could be affected by an extreme flood (0.1% chance in any year).
The assessment takes into account the type, location and condition of flood defences, and the chance of these defences being overtopped or breached during major floods. The likelihood of flooding and the consequent costs (economic damages) are assessed for each 50m square impact zone.
It does not include other forms of flooding such as highway drains, sewers, overland flow or rising groundwater.
Frequency of publication
AnnualData reference periods
2014 onwardsRounding applied
None.Statistical quality
The NaFRA includes flooding from all rivers with a catchment size greater than 3 square kilometres, and all flooding from the sea (both along the open coast and tidal estuaries). Smaller rivers are included in the assessment where they fall within the area that could be affected by an extreme flood (0.1% chance in any year).The assessment takes into account the type, location and condition of flood defences, and the chance of these defences being overtopped or breached during major floods. The likelihood of flooding and the consequent costs (economic damages) are assessed for each 50m square impact zone.
It does not include other forms of flooding such as highway drains, sewers, overland flow or rising groundwater.
Weblinks
http://lle.gov.wales/catalogue/item/Rofras/?lang=enhttps://naturalresources.wales/our-evidence-and-reports/maps/flood-risk-map/?lang=en