BGS news

BGS maps help understand relationship between groundwater and fracking.

03/07/2014 By BGS Press
Left: Full extent of potential shale gas/oil source rocks in England and Wales. Right: Full extent of Principal Aquifers in England and Wales (blue), extent of aquifers shallower than 400 m (pale blue).
Left: Full extent of potential shale gas/oil source rocks in England and Wales. Right: Full extent of Principal Aquifers in England and Wales (blue), extent of aquifers shallower than 400 m (pale blue).

The British Geological Survey (BGS) in partnership with The Environment Agency (EA) have today, for the first time, published a series of maps which show the depth to each shale gas and oil source rock below principal groundwater aquifers in England and Wales. Understanding the distance between the two is important when assessing the environmental risks of shale gas and oil exploitation.

Groundwater from aquifers provides 30% of drinking water in the UK and up to 70% of the drinking water in South East England making it one of the most important natural resources in the UK – a resource that needs effective long-term protection.

The maps provide a new way to visualise geological data. They will help technical and public understanding of the distance between principal aquifers and the shales/clays of interest for shale gas and oil exploitation, an important factor when considering the potential contamination risks from hydraulic fracturing and oil/gas well operation. The Environment Agency also requires detailed geological assessments if hydraulic fracturing for oil or gas is proposed, and requires operators to hold groundwater permits unless there is no significant risk to groundwater. Developments will not be allowed to go ahead if they are too close to drinking water sources, and the Environment Agency will not permit the use of chemical additives in hydraulic fracturing fluid that are hazardous to groundwater.

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Dr Rob Ward, Director of Groundwater Science, British Geological Survey said:

“For the first time the public will be able to visualise our nationally important Principal Aquifers in relation to potential shale gas and oil source rocks. This information will help to better understand the risks to groundwater from shale gas and oil.”

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Dr Alwyn Hart, Head of the air, land and water research team at the Environment Agency said:

“We have strong regulatory controls in place to protect groundwater, and will not permit activity that threatens groundwater and drinking water supplies. These maps will help public understanding of the separation between groundwater and potential shale gas sites.”

The maps show that:

  • The Principal Aquifers (main drinking water aquifers) are present across a large part (81%) of England and Wales.
  • Shales and clays which have potential for shale gas/oil are present over more than half (51%) of England and Wales.
  • Almost half (47%) of the area where Principal Aquifers are present is underlain by one or more of these shales or clays.
  • The Bowland Shale, an important potential target for shale gas development, is generally (92%) at least 800 m below the Principal Aquifers actively used as a source of drinking water. There are six Principal Aquifers above the Bowland Shale. These are: the Chalk, Lower Greensand, Corallian Limestone, Oolite, Magnesian Limestone and Triassic sandstones.
  • The Chalk aquifer of the South Downs is above part of the area in The Weald Basin identified as prospective for shale oil. In this area the uppermost shale oil source rock (Kimmeridge Clay) is at least 650 m below the Chalk. See figure below.

The maps will also have other uses, for example in relation to the development of other unconventional hydrocarbons and carbon capture and storage.

The maps and data are freely available from the BGS website: www.bgs.ac.uk/aquifers-shales.

Cross-section across southern England (including The Weald) showing the three potential shale oil source rocks and the Chalk aquifer (solid blue indicates the part exploited for drinking water).
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Cross-section across southern England (including The Weald) showing the three potential shale oil source rocks and the Chalk aquifer (solid blue indicates the part exploited for drinking water).

National Methane Baseline Survey

At the same time as the publication of the aquifer – shale maps, BGS are also publishing new data on methane in UK groundwater: the National Methane Baseline Survey. BGS supported by the EA and Defra has been undertaking a survey of methane concentrations in UK aquifers to provide a baseline against which any future changes can be measured. This has become particularly important with increasing interest in shale gas and other unconventional hydrocarbons in the UK. Data summaries and maps of the new baseline data are now freely available from the BGS website: www.bgs.ac.uk/research/groundwater/shaleGas/methaneBaseline/home.html.

For further details or to arrange media interviews please contact:

Sarah Nice, BGS Press Office, Keyworth, Nottingham, NG12 5GG
Office: +44 (0)115 936 3605          Mobile: +44 (0)7989 115657
E-mail: sebr@bgs.ac.uk                  Twitter @Sarahnice1

James Bertin, EA Press Office, London, SW1P 2AL
Office +44 (0)203 263 8156           Mobile +44 (0)7833 042 507
Email: james.bertin@environment-agency.gov.uk

The following are available for interview:

  • Dr Rob Ward, British Geological Survey
  • Dr John Bloomfield, British Geological Survey
  • Dr Tony Grayling, Environment Agency

 

For additional information go to: www.bgs.ac.uk

Photographs are available from our ftp server: ftp://ftp.bgs.ac.uk/pubload/bgspress

Free for media use with this acknowledgement: British Geological Survey©NERC

The British Geological Survey

The British Geological Survey (BGS), a component body of the Natural Environment Research Council (NERC), is the nation’s principal supplier of objective, impartial and up-to-date geological expertise and information for decision making for governmental, commercial and individual users. The BGS maintains and develops the nation’s understanding of its geology to improve policy making, enhance national wealth and reduce risk. It also collaborates with the national and international scientific community in carrying out research in strategic areas, including energy and natural resources, our vulnerability to environmental change and hazards, and our general knowledge of the Earth system. More about the BGS can be found at www.bgs.ac.uk.

The Natural Environment Research Council

The Natural Environment Research Council (NERC) is the UK’s main agency for funding and managing world-class research, training and knowledge exchange in the environmental sciences. It coordinates some of the world’s most exciting research projects, tackling major issues such as climate change, food security, environmental influences on human health, the genetic make-up of life on earth, and much more. NERC receives around £300 million a year from the government’s science budget, which it uses to fund research and training in universities and its own research centres. www.nerc.ac.uk

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