Flood Risk Assessment Wales (FRAW)

Flood Risk Assessment Wales provides a national assessment of risk flooding from Rivers, the Sea and Surface Water and Small Watercourses. The assessment takes into account flood defences and combines new, national-scale modelling with detailed local-scale models to categories risk into 3 bands, labelled ‘High’, ‘Medium’ and ‘Low’ risk.

Identifier: NRW_DS124841

Alternative Title

Flood Risk from Surface Water and Small Watercourses
Flood Risk from the Sea
Flood Risk from Rivers

Metadata Language: English

Lineage: For Rivers and Surface Water and Small Watercourses: ‘High’ risk means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%) ‘Medium’ risk means that each year, an area has a chance of flooding of between 1 in 100 (1%) and 1 in 30 (3.3%). ‘Low’ risk means that each year, an area has a chance of flooding of between 1 in 1000 (0.1%) and 1 in 100 (1%). For the Sea: ‘High’ risk means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%) ‘Medium’ risk means that each year, an area has a chance of flooding of between 1 in 200 (0.5%) and 1 in 30 (3.3%). ‘Low’ risk means that each year, an area has a chance of flooding of between 1 in 1000 (0.1%) and 1 in 200 (0.5%) The risk assessment takes into account the effect of flood defences where we have information. Flood defences reduce, but do not completely stop the chance of flooding as they can be overtopped or fail. Flood risk information for each source has been created as ‘onion-skins’, i.e. with no overlapping data between individual risk bands. These risk bands should be combined and displayed a single layer for each flood source. If data is displayed in map form to others, appropriate map scales should be used given the indicative nature of the modelling. It should be shown with a maximum zoom scale of 1:5,000 and that base mapping of 1:10,000 is used to give context. The flood mapping is based on areas at risk of flooding and is not specific to individual properties. NRW doesn’t hold information about an individual property’s construction that might affect whether flooding of a certain depth could enter a property and cause damage. As such, our information has been produced to identify general areas potentially at risk of flooding for further investigation. Spatial resolution of the data: National scale modelling undertaken at 2m grid resolution. Local scale modelling undertaken at different resolutions, typically between 2m – 10m.

Additional Information: More information is available in the FRAW (2019) project report and NRWs Understanding your flood risk results webpage ( https://naturalresources.wales/flooding/managing-flood-risk/understanding-your-flood-risk-results?lang=en ) for more information on our flood risk data and how it should be used.

Dataset Reference Date (Publication): 2023-11-30

Temporal Extent

Begin date: 2018-09-01

Topic category

Inland waters
Environment

Owner

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Originator

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Extent

Geographic Extent: Wales (WLS)

Distribution

Format Type and Description

Geographic Information System ()

Specification

ESRI Feature Class

Resource Locator

Download data and Web Service

World Wide Web page

Resource Locator

Web Mapping Service

World Wide Web page

Data quality

Quality Scope: Dataset

Conformity: 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
Explanation
Degree: false

Lineage: For Rivers and Surface Water and Small Watercourses: ‘High’ risk means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%) ‘Medium’ risk means that each year, an area has a chance of flooding of between 1 in 100 (1%) and 1 in 30 (3.3%). ‘Low’ risk means that each year, an area has a chance of flooding of between 1 in 1000 (0.1%) and 1 in 100 (1%). For the Sea: ‘High’ risk means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%) ‘Medium’ risk means that each year, an area has a chance of flooding of between 1 in 200 (0.5%) and 1 in 30 (3.3%). ‘Low’ risk means that each year, an area has a chance of flooding of between 1 in 1000 (0.1%) and 1 in 200 (0.5%) The risk assessment takes into account the effect of flood defences where we have information. Flood defences reduce, but do not completely stop the chance of flooding as they can be overtopped or fail. Flood risk information for each source has been created as ‘onion-skins’, i.e. with no overlapping data between individual risk bands. These risk bands should be combined and displayed a single layer for each flood source. If data is displayed in map form to others, appropriate map scales should be used given the indicative nature of the modelling. It should be shown with a maximum zoom scale of 1:5,000 and that base mapping of 1:10,000 is used to give context. The flood mapping is based on areas at risk of flooding and is not specific to individual properties. NRW doesn’t hold information about an individual property’s construction that might affect whether flooding of a certain depth could enter a property and cause damage. As such, our information has been produced to identify general areas potentially at risk of flooding for further investigation. Spatial resolution of the data: National scale modelling undertaken at 2m grid resolution. Local scale modelling undertaken at different resolutions, typically between 2m – 10m.

Keywords

GEMET - INSPIRE themes, version 1.0

Natural risk zones

Type: Theme

Citation

Date (Publication): 2008-06-01

Code: geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus

flood risk
flood modelling

Type: Theme

Citation

Date (Publication): 2023-12-31

Code: geonetwork.thesaurus.local.theme.converted_nrw-keywords

Code: British National Grid (EPSG::27700)

Content Information

NRW Profile

Custom Elements

Constraints

Limitations on Public Access and Use

Restriction type: Other restrictions

Access Constraints Directive

Limitations: no limitations

Access Constraints Text

Other constraints: There are no access restrictions on this data. NRW may release, publish or disseminate it freely.

Use Constraints

Use constraints type: Other restrictions

Other constraints: © CNC/NRW and UKCEH Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose.

Attribution Statement

Other constraints: Open Government Licence (OGL)

Licence

Other constraints: Open Government Licence (OGL)

Metadata

File Identifier: 4f4c4942-4343-5764-6473-313234383431 XML

Metadata Language: English

Resource type: Dataset

Metadata Date: 2024-05-30T15:17:27.936Z

Metadata Standard Name: NRW

Metadata Standard Version: 1.0

pointOfContact

Natural Resources Wales (NRW)

Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales

http://naturalresources.wales/?lang=en

Publishing Body

Access the portal

Full access to the portal and metadata.

Flood Risk Assessment Wales (FRAW)

Identification

Temporal Extent

Extent

Extent

Distribution

Distribution

Quality

Data quality

Keywords

Keywords

Citation

Keywords

Citation

Spatial Reference System

Content

Content Information

NRW Profile

Custom Elements

Constraints

Constraints

Limitations on Public Access and Use

Access Constraints Directive

Access Constraints Text

Use Constraints

Attribution Statement

Licence

Metadata

Metadata

Publishing Body