Guidance

Bristol and Gloucester - Subregion 3

National Geological Screening for a GDF - Bristol and Gloucester region

This screening report hosted on this site is a technical exercise across England, Wales and Northern Ireland. No specific location in England, Wales or Northern Ireland has been identified as a potential GDF site. Any future decision on geological disposal would be subject to community agreement and planning and environmental consents.

Details

Our work shows that we may find a suitable geological setting for a GDF in a small part of this subregion, but the potential rock may not be present in suitably shaped or sized volumes.

Bristol and Gloucester - Subregion 3

Rock can be seen at the surface in some of the subregion such as the Forest of Dean, the Avon and Cheddar Gorges and the Mendips and in man-made excavations such as quarries or road cuttings. Combined with some deep boreholes and geophysical investigations, this gives us an understanding of the rocks present and their distribution.

There are various types of gaps in our understanding of geology and we deal with these gaps in a number of ways.

There are clay-rich rock layers south of Bristol, around Weston-super-Mare and between Wells and Frome, in which we may be able to site a GDF. There are also volcanic lavas and similar strong rocks between Wells and Frome, in which we may be able to site a GDF. These rocks may not be present in suitably shaped or sized volumes and we would need to do more work to find out whether they have suitable properties and thicknesses.

Even where individual clay-rich rock layers are found not to be thick enough to host a GDF they may support the siting of a GDF in deeper rocks as they could act as a barrier to groundwater flow from depth. This is important because movement of groundwater is one of the ways in which radioactive material could be carried back to the surface.

Some of the subregion has been mined for coal resources to depths below 100m, in the Forest of Dean and around Bristol and Midsomer Norton and iron ore to depths below 100m, also in the Forest of Dean. In these areas the mining is likely to have affected the way in which water moves through the rock. Also possible exploration in the future in these areas means that it is more likely that future generations may disturb a facility.

Parts of the Forest of Dean are also Coal Authority Licence Areas allowing companies to explore for coal. It is not known whether coal in these licence areas will be exploited. RWM will continue to monitor how this exploration programme progresses.

The area around Weston-super-Mare has Petroleum Exploration and Development Licences to allow companies to explore for oil and gas. This exploration is currently at an early stage and it is not known whether oil or gas in these licence areas will be exploited. RWM will also continue to monitor how this exploration programme progresses.

There are thermal springs in Bristol and Bath which indicate that groundwater is moving rapidly from depth to the surface in these areas. This would need to be considered in the siting of a GDF in this subregion.

For further information, read the report below.

Bristol and Gloucester Subregion 3

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We have also produced a summary of the geological attributes of the Bristol and Gloucester Region.

Go to National Geological Screening for a GDF

Go to geological disposal homepage

Published 19 December 2018