The Cretaceous, Jurassic and Permian carbonate karst aquifers of England (UK)

Despite having limited cave development, the UK Permian, Jurassic and Cretaceous carbonates have standard karst features – caves, stream sinks, dolines, springs, dry valleys, and solutional networks of fissures and conduits extending multiple kilometres. This paper provides a new discussion and comparison of these karst aquifers, demonstrating that significant karst features are widespread. Tracer tests in the Chalk and Jurassic limestones demonstrate flows of thousands of metres per day from the surface to a spring or abstraction over many kilometres, comparable to results from karst aquifers with substantial cave systems, such as the UK Carboniferous limestones. They are less vulnerable in terms of having less cave development and a lower proportion of rapid point recharge, with greater attenuation via flow through smaller voids. However, the combination of long-distance transport via karstic networks and long-term storage of contaminants in smaller voids may make contaminant management particularly challenging. Karst development and the proportion of rapid recharge vary substantially at different spatial scales. Therefore, better groundwater conceptual models incorporating karst data at the local catchment scale, together with further investigations (tracer tests, borehole studies, water balance) are needed. Groundwater management and protection require the use of methods appropriate to the karstic nature of these aquifers.