Caves and karst of the Chalk in East Sussex, UK: implications for groundwater management

The Upper Cretaceous Chalk of East Sussex is well exposed on the coastal cliff sections between Brighton and Eastbourne. Previous work by Terry Reeve and members of the Chelsea Spelaeological Society identified several caves along the Sussex coast, highlighting the presence of karst. Other evidence of karst comes from active conduits intersected in boreholes and in adits dug for groundwater abstraction, dissolution pipes and cavities encountered in construction projects, and dolines observed on remote sensing data. To understand the extent of cave and conduit development in the Chalk, and how they are related to Chalk lithostratigraphy, a review of the evidence for karst in the area was undertaken, coupled with a detailed survey of the coastal section between Seaford and Eastbourne. Over 50 cave and karst features were identified along the coast, the vast majority being associated with key inception horizons in the Chalk, particularly marl seams and sheet flints. Some are developed on vertical fractures. The data are used to develop a conceptual understanding of Chalk karst and examine the implications for groundwater management.