Methodology
| Name | Category | Description |
|---|---|---|
| Regulated Sites | Contaminated Land | Regulated Sites encompasses all Part A(1) sites which are regulated by the Environment Agency or Natural Resources Wales. The dataset includes closed mining areas, end-of-life vehicle treatment sites (operational for 7 years or more), open waste permitted sites, radioactive substance permitted sites, and industrial installations. 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). |
| Fluvial (undefended) | Flood Risk, Flood Risk | This dataset provides modelled information on river flood risk under an undefended scenario, assuming that flood defences may fail. The risk rating combines how likely flooding is in any given year with how deep the water is expected to be at the property. JBA models a range of scenarios, from a frequent 1 in 10 year chance of flooding through to a rare 1 in 1,000 year chance, and for each records the greatest modelled water depth. Both factors matter: more frequent flooding and deeper water increase the risk, so shallow water in a very rare event is treated as lower risk, while deeper water, or water from a more frequent event, raises it. Depth is assessed in bands around 0.05m, 0.1m, 0.3m and 1m. The property is then rated on its worst scenario as suitable, possibly suitable or unsuitable. Since the data is modelled, no physical inspections have been conducted by Martello or JBA Risk Management. There may be other localised factors such as blocked drains which could also impact flooding. Please note, Martello reports created prior to mid-July 2026 used an alternate model and methodology. Please contact support@martello.app if you require these details. |
| Groundwater | Flood Risk, Flood Risk | This dataset provides modelled information on susceptibility to groundwater flooding using the British Geological Survey’s Groundwater Flooding dataset. It identifies areas where geological and hydrogeological conditions could enable groundwater flooding to occur, including where groundwater may come close to the ground surface. Land is classified by susceptibility: limited potential, potential for flooding of property below ground level, or potential for groundwater flooding at the surface. The dataset is derived from national geological and hydrogeological data using rule-based modelling, and should be interpreted as susceptibility rather than a prediction of flood depth, probability, or site-specific risk. No property-specific physical inspections have been conducted by Martello. |
| Tidal (undefended) | Flood Risk, Flood Risk | This dataset provides modelled information on seawater (tidal) flood risk under an undefended scenario, assuming that flood defences may fail. The risk rating combines how likely flooding is in any given year with how deep the water is expected to be at the property. JBA models a range of scenarios, from a frequent 1 in 10 year chance of flooding through to a rare 1 in 1,000 year chance, and for each records the greatest modelled water depth. Both factors matter: more frequent flooding and deeper water increase the risk, so shallow water in a very rare event is treated as lower risk, while deeper water, or water from a more frequent event, raises it. Depth is assessed in bands around 0.05m, 0.1m, 0.3m and 1m. The property is then rated on its worst scenario as suitable, possibly suitable or unsuitable. Since the data is modelled, no physical inspections have been conducted by Martello or JBA Risk Management. There may be other localised factors such as blocked drains which could also impact flooding. Please note, Martello reports created prior to mid-July 2026 used an alternate model and methodology. Please contact support@martello.app if you require these details. |
| Pluvial | Flood Risk, Flood Risk | This dataset provides modelled information on surface water (pluvial) flood risk. The risk rating combines how likely flooding is in any given year with how deep the water is expected to be at the property. JBA models a range of scenarios, from a frequent 1 in 10 year chance of flooding through to a rare 1 in 1,000 year chance, and for each records the greatest modelled water depth. Both factors matter: more frequent flooding and deeper water increase the risk, so shallow water in a very rare event is treated as lower risk, while deeper water, or water from a more frequent event, raises it. Depth is assessed in bands around 0.05m, 0.1m, 0.3m and 1m. The property is then rated on its worst scenario as suitable, possibly suitable or unsuitable. Since the data is modelled, no physical inspections have been conducted by Martello or JBA Risk Management. There may be other localised factors such as blocked drains which could also impact flooding. Please note, Martello reports created prior to mid-July 2026 used an alternate model and methodology. Please contact support@martello.app if you require these details. |
| 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 and any new schemes, decommissioned assets or changes in defence standards are only correct as of the last data update from the Environment Agency and Natural Resources Wales. 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. |
| Historical Flood Areas | Flood Risk | This dataset shows the maximum extent of individual Recorded Flood Outlines from river, sea and groundwater springs that meet a set criteria. This excludes flooding from surface water, except in areas where it is impossible to determine whether the source is fluvial or surface water but the dominant source is fluvial. If an area is not covered by the Historic Flood Map it does not mean that the area has never flooded, only that EA or NRW do not currently hold a record of flooding in this area. Additionally, flooding is shown to the land and does not necessarily indicate that properties were flooded internally. |
| Green Belt | Planning Constraints | This dataset shows green belt boundaries. Green belt exists to protect the countryside from urban sprawl and to retain the character of towns and cities. |