GeoSmart releases latest update to Groundwater Flood Risk Map

The update will offer more accurate data than ever before to a growing user base of customers.

Since its introduction in 2013, the GW5 map has been used to screen more than 2.2 million UK property transactions. The map is used by water companies, local authorities and developers to assess risk to infrastructure and planning applications for new development. Groundwater flooding is becoming increasingly recognized as an important contributor to UK flood risk, and climate change is set to make this worse. Groundwater should be assessed as part of any robust flood risk assessment and drainage strategy.

GeoSmart’s Groundwater Flood Risk Map (GW5 version 2.3) is the most sophisticated and accurate map available on the market, using a five metre dataset to provide detailed groundwater flood risk information at the individual property scale. The latest version of the map offers improvements to version 2.2 with an updated elevation model that includes Scottish LiDAR data and the most recent OS data. We have also upgraded the representation of aquifer permeability within the map to provide even better definition of risk areas.

Combining comprehensive data on geology, permeability and historic groundwater levels, it is a major improvement on other maps, which are based on older data and indicate potential susceptibility to groundwater emergence rather than specific risk. The map takes account of flooding from ‘clearwater’ bedrock flooding but also includes flooding from permeable superficial deposits which can have major implications in river valleys and coastal areas.


The map delivers address level insight which will have significant implications in terms of due diligence for land purchase, insurance premium calculations, and property resilience planning. Planning applications should consider the implications of groundwater within the flood risk assessment (FRA) and potential impacts on drainage features such as sewers, soakways and SuDs infiltration systems. Peak levels vary significantly both during and between years, so the map can be used to highlight areas at risk from extreme events, which may otherwise be missed by limited site investigation.

The granularity of risk boundaries, topography and integration with other 5m surface and fluvial flooding datasets, means the map provides far more “real world” clarity than ever before.

Paul Ellis, Managing Director of GeoSmart, explained:

“Groundwater flooding is the hidden face of flood risk and our latest update to the map reflects GeoSmart’s ongoing investment in delivering the best data available in the market with unequalled accuracy’’.

‘’The GeoSmart groundwater flood risk map GW5 provides an estimate of the groundwater flood risk on a consistent national scale. This ensures far more informed planning, with major benefits for the property, infrastructure and insurance industries. Little has been done to protect existing property and the impact of groundwater flooding now and, in the future, should not be underestimated.’’

‘’The UK’s climate is changing, and this will potentially increase the frequency, severity and extent of groundwater flooding. Businesses and individuals should take action to assess vulnerability and improve resilience if they are at risk from groundwater flooding and climate change. The first step in this process is to establish the current baseline risk using the GW5 risk envelopes.’’

‘’The potential for higher peaks in groundwater level increases under many of the climate change scenarios driven by more intense rainfall recharge, plus increases in peak river stage and sea level rise of over 1 metre causing increased levels in the adjacent aquifers.’’

“Enhancing resilience to extreme weather will be an important aspect of future economic competitiveness, and mapping of groundwater flood risk areas provides essential preparation for emergency response, flood mitigation and land-use planning, as well as the assessment of climate change impact,” concluded Paul.

GeoSmart also provides a groundwater flood forecasting service, used by the Flood Forecast Centre, utility companies and councils, which can be used in combination with the groundwater flooding maps to add significant value to the asset management, infrastructure and insurance sectors.

For more information about the GeoSmart Groundwater Flood Risk Map, please visit or call 01743 298 100, or email