OR/18/006 About the GeoClimate dataset

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Harrison, A, Jones, L, Entwisle, D, Hulbert, A, Lark, M, Mansour, M, Richardson, J, Wang, L, and White, J. 2018. User guide for the British Geological Survey GeoClimate: clay shrink-swell dataset. British Geological Survey. (OR/18/006).

Background

Public understanding of the effect of ground conditions on the safety of their property and the implication for the value of their property is growing. Local councils are under increasing pressure from central government to provide environmental information. Information about geological hazards is needed, in particular, the identification of areas with a potential for ground movement.

In response to this, The British Geological Survey initiated a development programme to produce datasets that identified and assessed potential geohazards threatening the human environment in Great Britain. Along with the GeoSure ground stability datasets, the programme also generated:

  • Superficial Deposit Thickness Models
  • Ground permeability data
  • Susceptibility to groundwater flooding data
  • Geological indicators of past flooding data
  • GIS data identifying potential radon hazard
  • mining hazards (Non-coal) data
  • GeoSure Shrink-Swell 3D London & the Thames Valley data
  • GeoSure Debris Flow data

Who might require this data?

Natural ground stability hazards may lead to financial loss for anyone involved in the ownership or management of property, including developers, householders or local government. These costs could include increased insurance premiums, depressed house prices and, in some cases, engineering works to stabilise land or property. These hazards may also impact on anyone involved in the construction of large structures (deep foundations, basements), infrastructure networks (road or rail) or utility companies.

Armed with knowledge about potential hazards, preventative or mitigative steps can be put in place to alleviate the impact of the hazard to people, property and infrastructure. The cost of such prevention may be very low, and is often many times lower than the repair bill following ground movement.

The identification of areas of potential increased risk of Shrink-Swell susceptibility from climate change will be of use to all users planning for longer-term resilience such as developers, construction companies, and utility companies, consulting engineers, builders, loss adjusters, the insurance industry, architects and surveyors.

What the dataset shows?

Shrink-swell is recognised as the most significant geohazard across Great Britain. The purpose of this dataset is to provide information on the change in susceptibility of Shrink-Swell across Great Britain due to a changing climate and the associated changes in soil moisture.

Swelling clays can change volume due to variation in moisture, this can lead to ground movement, particularly in the upper two metres of the ground, or where excavated and exposed, that may affect many foundations. Ground moisture variations may be related to a number of factors, including weather variations, vegetation effects (particularly growth or removal of trees) and the activities of people that might cause changes to the ground conditions. Such changes can affect building foundations, pipes or services.

This stand-alone product consists of a suite of data layers, in Geographical Information System (GIS) format that temporally identifies areas of shrink-swell hazard with a change in susceptibility of clay shrink-swell across GB. The UKCP09 climate projections for rainfall and temperature have been utilised to project changes in clay shrink-swell susceptibility, provided for the time periods 2020s, 2050s and 2080s.

‘GeoClimate’ utilises the medium emissions scenario of the UKCP09 climate projections (www.ukclimateprojections.metoffice.gov.uk/). It is essentially a national hazard susceptibility map, showing change in susceptibility with time, due to changes in climate. This methodology has been developed by Engineering Geologists, Hydrogeologists, Geophysicists and Information Developers at the British Geological Survey and is presented as GIS data layers.

GeoClimate: Shrink-Swell is provided in two options, a simple overview dataset (GeoClimate Basic) and a detailed dataset (GeoClimate Premium). The content of each is described below.

GeoClimate Basic:

  • Freely available suite of layers under Open Government Licence
  • Provides a 2 km generalised vector grid of the projected effects of climate change on clay shrink-swell susceptibility in GB, calculated for 11 year windows.
  • Provided for 3 time periods
- 2030 (2025 to 2035)
- 2050 (2045 to 2055)
- 2080 (2075 to 2085)
  • 1 projection is provided for each time period: average climate projection
  • Based on the average outcome for the medium emissions scenario and the most susceptible GeoSure value (worst case) within the grid cell.

GeoClimate Premium:
More detailed suite of layers, provided in polygons that are derived from BGS GeoSure vector data.

  • It provides a higher resolution (1:50K) view of the GeoClimate shrink-swell projections, calculated for 11 year windows.
- 2020 (2015 to 2025)
- 2030 (2025 to 2035)
- 2040 (2035 to 2045)
- 2050 (2045 to 2055)
- 2080 (2075 to 2085)
  • 3 projected scenarios for each time period: average, wetter and drier climate projections are provided