Modelling and Mapping
Within the UK there is a good understanding of the potential flood risk from rivers, the sea, surface water and reservoirs, with freely available flood hazard mapping. In comparison, there is limited understanding about the risk for groundwater flooding and the potential impact to communities, with few methods to assess the potential flood risk. There are no such freely available national or regional maps of groundwater flood risk that provide the same level of detail to the other forms of flooding. This has contributed to the under-recognition of groundwater flooding and limited management of the risk.
The primary aim of the groundwater modelling and mapping workstream is to develop approaches to model where groundwater levels could rise to be near the ground surface and how the water would then flow over the ground surface once it has emerged. The results from this modelling will be used to develop groundwater flood risk maps across the Project Groundwater area, which will feed into the development of a flood warning system, provide a freely available resource for local communities, raise awareness of groundwater flood risk, along with informing groundwater management schemes and planning applications.
During the first phase of work, we reviewed and investigated different techniques for modelling groundwater levels across areas of Chalk and permeable superficial deposits, including new and innovative approaches. This ranged from relatively simple methods to more complex multi-layered groundwater models, and the outcomes identified preferred methods for modelling groundwater flood risk across the unconfined Chalk.
In 2023 we started work on the second phase of the modelling and mapping workstream, which will continue into 2024. We are implementing the preferred modelling techniques to create a library of groundwater flood risk maps for the unconfined Chalk across the Project Groundwater area. These maps will show the different levels of risk for a range of groundwater levels, and will be used within the groundwater flood warning web-application.
To support this, we are engaging with the local focus communities to present and consult on the format of the maps. This will help to ensure that information shown on the maps is clear, understandable, and provides the level of information needed to understand the flood risk within a community. We are gathering and collating feedback from the communities and incorporating this into the final maps.
We are also continuing to investigate and test methods for modelling the groundwater flood risk across areas of permeable superficial deposits.
Groundwater flood map for Marlow, Buckinghamshire. This map has been designed by our partner Jacobs to show that high groundwater levels can cause damage both underground and overground. The map is being used by our engagement team to explore with the community whether the areas at risk on the map match their experience with groundwater flooding
Find out more about Project Groundwater
