Groundwater Level Network Review – Standard Groundwater Index modelling of 40 sites across Wales

The Geoscience Team have set up a project to review the groundwater level data we hold from

across our groundwater monitoring network (130 sites). We have chosen 40 site to look at in

more detail using the modelling code the British Geological Survey (BGS) have developed to

get a standard groundwater index (SGI).

The aim of the project is to use the AquiMod 2 groundwater model (Mackay et al. 2022) in

conjunction with historical, bias corrected climate data to reconstruct daily groundwater level time series back to 1894 at each borehole, before calculating an equivalent standardised time

series which can be used to assess the historical occurrence of groundwater drought at each

borehole.

Once the data is processed through the modelling code, we (NRW in house) can then use this

data to compare and review groundwater levels from sites with different geologies and

geographical areas from around Wales in a standardised way. This allows analysis of drought

response and allow us to consider drought management in the future.

The BGS have developed the modelling code to determine the SGI. They are the only

organisation within the UK that can use the modelling code as the code is not commercially

available. As the BGS are the only organisation we must follow the Single Tender Action

procurement process to secure a contact for the works.