Methodology
| Name | Category | Description |
|---|---|---|
| Regulated Sites | Contaminated Land | Regulated Sites encompasses closed mining areas, end-of-life vehicle treatment sites (operational for 7 years or more), open waste permitted sites, and industrial environmental permitted regulated facilities (permit types A and B only). Mobile sites and sites with no specified address may be excluded. |
| Historic Land Use | Contaminated Land | This dataset provides information on past industrial land use depicted on historic Ordnance Survey maps which could lead to a liability under Part2A of the Environmental Protection Act (1990). |
| Rivers and Seas | Flood Risk | This dataset provides information on the extent of land at present day risk of flooding from rivers and the sea, ignoring the benefits of defences. Land is classified as 'medium' or 'high' risk based on the probability of flooding, which differs between England and Wales. In England, medium risk applies to areas with greater than or equal to 0.1% (1 in 1000) chance of flooding in any given year, while high risk applies to areas with a greater than or equal to 1% (1 in 100) chance for river flooding and 0.5% (1 in 200) for tidal flooding in any given year. In Wales, medium risk applies to areas with greater than or equal to 1% (1 in 100) chance for river flooding and 0.5% (1 in 200) for tidal flooding in any given year, while high risk applies to areas with a greater than or equal to 3.3% (1 in 30) chance in any given year. Since the data is modelled, no physical inspections have been conducted by Martello. There may be other localised factors such as blocked drains which could also impact flooding. Some features of this information are based on digital spatial data licensed from the UK Centre for Ecology & Hydrology © UKCEH. Defra, Met Office and DARD Rivers Agency © Crown copyright. © Cranfield University. © James Hutton Institute. Contains OS data © Crown copyright and database right. |
| Surface Water | Flood Risk | This dataset provides information on the modelled flood risk from surface water. Land is classified as 'medium' or 'high' risk based on the probability of flooding and predicted water depth. Medium risk applies to areas with less than 3.3% (1 in 30) but greater than or equal to 0.1% (1 in 1000) chance in any given year, while high risk applies to areas with greater than or equal to 3.3% chance in any given year (1 in 30). Since the data is modelled, no physical inspections have been conducted by Martello. There may be other localised factors such as blocked drains which could also impact flooding. Some features of this information are based on digital spatial data licensed from the UK Centre for Ecology & Hydrology © UKCEH. Defra, Met Office and DARD Rivers Agency © Crown copyright. © Cranfield University. © James Hutton Institute. Contains OS data © Crown copyright and database right. |
| Fluvial (undefended) | Flood Risk | This dataset provides modelled information on river flood risk under an undefended scenario, assuming that flood defences may fail. Land is classified as 'medium' or 'high' risk based on the probability of flooding and predicted water depth. Medium risk applies to areas with a 1 in 1,000 probability or 1 in 100 with water depth below 0.2m, while high risk applies to areas with a 1 in 100 probability and depth above 0.2m or a 1 in 10 probability. Since the data is modelled, no physical inspections have been conducted by Martello or GeoSmart. There may be other localised factors such as blocked drains which could also impact flooding. |
| Groundwater | Flood Risk | This dataset provides modelled information on groundwater flood risk using GeoSmart's GW5 product. Land is classified as 'medium' or 'high' risk based on the probability of flooding and predicted water depth. GW5 incorporates a 5m Digital Terrain Model (DTM) for enhanced resolution at an individual property level revealing the complex relationship between terrain and “ponding” of groundwater. Since the data is modelled, no physical inspections have been conducted by Martello or GeoSmart. |
| Tidal (undefended) | Flood Risk | This dataset provides modelled information on seawater flood risk under an undefended scenario, assuming that flood defences may fail. Land is classified as 'medium' or 'high' risk based on the probability of flooding and predicted water depth. Medium risk applies to areas with a 1 in 1,000 probability or 1 in 100 with water depth below 0.2m, while high risk applies to areas with a 1 in 100 probability and depth above 0.2m or a 1 in 10 probability. Since the data is modelled, no physical inspections have been conducted by Martello or GeoSmart. There may be other localised factors such as blocked drains which could also impact flooding. |
| Pluvial | Flood Risk | This dataset provides information on the flood risk from surface water. This dataset provides modelled information on surface water flood risk. Land is classified as 'medium' or 'high' risk based on the probability of flooding and predicted water depth. Medium risk applies to areas with a 1 in 1,000 probability or 1 in 100 with water depth below 0.2m, while high risk applies to areas with a 1 in 100 probability and depth above 0.2m or a 1 in 10 probability. Since the data is modelled, no physical inspections have been conducted by Martello or GeoSmart. There may be other localised factors such as blocked drains which could also impact flooding. |
| Flood Defences and Benefiting Areas | Flood Risk | This dataset shows national flood defence schemes and the areas benefiting from them. Flood defences can be man-made embankments and walls or naturally occurring e.g. shingle ridges and dunes. If the defences were not there, the areas benefiting from them would stand a 1% chance of flooding from rivers, and 0.5% from the sea. Not all benefiting areas are shown. Property level defences to protect individual properties are not included in this dataset. |
| Flood Storage Areas | Flood Risk | This dataset shows areas that act as a balancing reservoir, storage basin or balancing pond. Their purpose is to attenuate an incoming flood peak to a flow level that can be accepted by the downstream channel. It may also delay the timing of a flood peak so that its volume is discharged over a longer time interval. |