Investigation of the geology of the low-level radioactive waste burial site at Drigg, Cumbria

The geology of the low-level solid radioactive waste disposal site at Drigg, Cumbria has been investigated on the basis of a number of shallow excavations and 35 boreholes. The glacial sequence varies from 10 to 42 m in thickness and ranges from coarse sands and gravels to compact boulder clays. These overlie an irregular surface of St Bees Sandstone which probably contains a deep-erosion channel. The site is underlain by at least one boulder clay horizon. Clays restrict the direct downward movement of surface infiltration into the deeper permeable sands and gravels considered to be in hydraulic continuity with the St Bees Sandstone, but give rise to perched water tables in which lateral flow may occur. The streams which traverse the site are potentially influent throughout their length and may lose water to sand and peat deposits where these exist in the south-western part of the site. (author)