This report details Task 2 (“Development of semi-quantitative national maps for assessment of
potential impacts of Land Use and Climate Change and Groundwater Quality”) of Phase 2 of the
Environment Agency-BGS collaborative project “climate and land use change impacts on
groundwater quality”. This task has developed semi-quantitative maps of changes in
contaminant source term risks associated with land use futures, accompanied by maps of
metrics of changes in precipitation and temperature associated with climate change. The key
findings of this task are as follows.
An initial scoping workshop identified a very wide range of drivers, pressures, and groundwater
quality variables of interest. It also identified a wide range of users of information, covering both
technical and non-technical staff and a range of scales from national down to area and local. A
literature review of relevant land use and climate change datasets showed that the land use
futures developed under the SPEED project (Brown et al., 2022) associated with the Shared
Socioeconomic Pathways (SSPs) were the most appropriate to use for this task, accompanied
by climate change projections derived from UKCP18 and CHESS-SCAPE (Robinson et al.,
2022).
A semi-quantitative risk scoring methodology has been developed to link land use classes
reported in the land use futures to contaminant source term risk. This methodology has been
applied to land use futures under six scenarios and seven future time slices, with results
summarised by EA areas and aquifers. Across the SSPs there is a divergence of changes in
risk in some areas and commonality in others. Some common features across the SSPs
include: stable land use (and limited change in contaminant risk) in eastern England associated
with ongoing need for food production; afforestation (and reduction in contaminant risk) in
southern England; urbanisation and intensification of arable land in northern England (an
increase in contaminant risk).
CHESS-SCAPE data has been processed to produce maps of changes in precipitation
(seasonal mean and extreme temperature, number of wet days) and temperature (seasonal
mean) metrics for 10-year timesteps to 2070 for 4 Representative Concentration Pathways
(RCPs). Under RCP8.5 for 2070, this results in wetter winters (particularly in northern England
and coastal southern England) and drier summers (particularly in southern England), with the
largest increases in extreme winter precipitation in northwest England and on the south coast.
The greatest rises in mean air temperature are in greatest temperature rises in Solent and
South Downs and West Thames.
The data generated in this task represent exploratory futures which are designed to support
discussions with policymakers on the robustness of existing policies related to groundwater
quality, and to inform spatial prioritisation of future work based on where risk is likely to be
greatest. A next step would be to use the data generated in this task to inform the development
of coupled water and pollutant models to quantitatively assess the impact of the land use
futures on groundwater quality
