Model Instance Title:
Marlborough and Berkshire Downs, South-west Chilterns (MabSWeC) Model  
Model Instance Short Name:
Projections of climate for the 2080s from an ensemble of global climate models (GCMs) run under a medium–high (A2) emissions scenario are used to simulate changes in groundwater resources of a Chalk aquifer in central-southern England. Few studies that have investigated the impacts of climate change on groundwater resources have addressed uncertainty. In this work the uncertainty associated with use of a suite of GCM outputs in catchment scale impact studies is quantified. A range of predictions is obtained by applying precipitation and temperature change factors, derived from thirteen GCMs, to a distributed recharge model and a groundwater flow model of the Chalk aquifer of the Marlborough and Berkshire Downs and south-west Chilterns in the UK. The ensemble average suggests there will be a 4.9% reduction in annual potential groundwater recharge across the study area, although this is not statistically significant at the 95% confidence level. The spread of results for simulated changes in annual potential groundwater recharge range from a 26% decrease to a 31% increase by the 2080s, with ten predicting a decrease and three an increase. Whilst annual recharge is not found to change significantly, the multi-model results suggest that the seasonal variation in the groundwater resource will be greater, with higher recharge rates during a reduced period of time in winter. The spread of predictions for changes in river baseflow, at the bottom of the largest river sub-catchment, is from −16 to +33% in March and from −68 to −56% in October. The effects of climate change are shown to depend significantly on the type of land-use. It is concluded that further research is required to quantify the effect of different vegetation types on Chalk covered by different thicknesses of soil and their response to a changing climate  
Creation/Publication Date:
Hazards Floods   
Contact Details:
Chris Jackson   British Geological Survey   UK  
Model Code Name:
Time Interval Covered:
from: 01-Jan-1970   to: 31-Dec-2003
Spatial Extent:
Bounding Box (Lat/Long WGS84):
West: -2.001   East: -0.525   South: 51.303   North: 51.725  
Scope of Vertical Extent: Chalk and Palaeogene  
Vertical Extent (metres above OD) Maximum: 250   Minimum: 20    
Spatial Reference Systems of Datasets:
Horizontal Reference System: WGS 84
Vertical Datum: mean sea level height
Vertical Units: metre
Grid Resolution:
Spacing XSpacing YSpacing ZCells XCells YCells Z
1000   1000     102   48   3  

Time step interval: month   Time step value: 4
Additional information (science questions addressed, assumptions etc.):
Science Question   How does using the results from different climate models affect the impact of climate change on groundwater heads and baseflow in the chalk of the Marlborough Downs, Berkshire and South-west Chilterns?  
Boundary Condition   No flow all around; abstractions represent groundwater outflow to the London Basin in the south-east  
Initial Condition   Steady state  
Input Dataset NameVersionURL LinkParameterValueUnits
Input Data          
    Top of layers      
    Bottom of Layers      
    Hydraulic conductivity      
    storage coefficient      
    Storage coefficient      
    River location and parameters      
    Location of springs      
Output Dataset NameVersionURL LinkParameterValueUnits
Output Data          
    Grounmdwater head      
Documents and Published Papers available for this model instance: