The British Geological Survey (BGS) has developed a new model that provides a unique tool for simulating groundwater resources at a national scale, covering England, Scotland and Wales.

 Image: Hydrological parameterisation (left) and simulated groundwater heads (right). BGS © UKRI.

Groundwater accounts for the largest volume of liquid fresh water on Earth. It represents an essential resource for public and private supply, agriculture, industry and recreation around the world.

Groundwater flow can be visually shown through computer models, which helps us understand temporal variations in groundwater levels and interactions between groundwater and surface waters.

The British Groundwater Model (BGWM) is the first integrated groundwater model covering Great Britain to simulate transient groundwater dynamics and surface water/groundwater interactions at the national scale.

The model provides a tool for a general assessment of groundwater resources in British aquifers and for improving current representations of groundwater flow in existing UK-focused land-surface and water-quality models.

BGWM uses the MODFLOW 6 code and includes British 3D geology. Model parameters were calibrated against measured groundwater levels and estimated baseflows using the PEST code.

The next phase of development will involve increasing the sophistication of the parameterisation, as well as a more realistic simulation of aquifer–marine interactions (coastal processes). By undertaking this future work, the BGWM will be improved so that it will become a robust decision support tool to test different solutions in the context of a changing population and climate.

Marco Bianchi, BGS Principal Groundwater Modeller commented:

“This model represents the first attempt at simulating British groundwater systems as a whole. This is a tool that will be used to address a wide range of problems related to the use and conservation of groundwater resources at the national scale.”

The development of the BGWM was supported by the Hydro-JULES research programme through NERC National Capability funding. The programme, which aims to improve the understanding and simulation of the terrestrial hydrological cycle for the British mainland and global scales, is led by:

• UK Centre for Ecology & Hydrology
• BGS
• National Centre for Atmospheric Science
• National Centre for Earth Observation

Andrew Hughes, BGS: manager of the Hydro-JULES research programme said:

“This model is the culmination of dedication and hard work from many BGS colleagues over the last five years. It gives the UK groundwater community the ability to address national-scale groundwater resources questions for the first time.”