Infra-red linescan survey at Altnabreac, Northern Scotland

Abstract

During 1978, a desolate stretch of moorland, bog and lochans, around Altnabreac in northern Scotland, became famous. Apart from being the place where British Rail ‘lost’ a train, it was here that the first (and to date the only) UK field investigation into the suitability of granite as a host for high level radioactive waste was carried out. The objective of the work was to assess how easy it would be to measure the parameters necessary to predict the outcome of waste disposal at such a site. Despite the premature termination of the programme in 1981, much interesting work in an unusual hydrogeological environment was completed. Since hydrogeology has a major impact on safety assessment, understanding the movement of groundwater in fractured crystalline rocks, such as those underlying Altnabreac, was essential. In particular, the role of faults and major joints in controlling the directions of flow and the recharge and discharge zones was uncertain. The hydrogeological investigations included measurements in the twenty seven boreholes which were drilled, some limited surface hydrology and some preliminary groundwater flow modelling. The bulk of the data was from the boreholes which gave no direct information on the areal distribution of groundwater flow. Whilst the modelling indicated recharge and discharge areas, the groundwater component of stream flow was likely to be small and therefore the shore of the lake. Less spectacular, but perhaps more interesting from a groundwater viewpoint, are the warm springs within the swarm of dubh-lochs south of the loch. In this area