Burren Landscape Hydrology

It has been claimed, with some justification, that water, not rock, is the essence of the Burren. Drainage in the Burren is largely subterranean, as over many millennia water courses in the region worked their way underground, reappearing periodically after heavy rainfall events. A consistent supply of surface water in the Burren is thus a rare and valuable resource, largely confined to the River Caher in Fanore and other ephemeral flows.

As a result, rural areas in the Burren traditionally had to rely almost exclusively on a combination of rainwater collection tanks and small springs for their water supply. The absence of a consistent supply of water in the Burren uplands, particularly in the summer season, is also an important factor in the evolution of the 'winterage' tradition whereby animals are put on these grasslands over winter when more water is available.

Most of the central Burren (40% of the overall area) drains south into the Fergus, via the Elmvale springs north of Corofin. The northern Burren, consisting of the catchments of Ballyvaughan and Bell Harbour (12% and 14% of the Burren respectively) drains mainly through submarine outlets into the sea at Galway Bay. The western Burren, consisting of the catchments of Poulsallagh, Deereen, Caher and Fisherstreet (16% of the area) drains largely into the Atlantic Ocean.

One fascinating reflection of the unusual hydrology of the Burren is the profusion of turloughs in the region. Turlough is a term derived from the Irish words tuar and loch meaning 'disappearing lake'. Turloughs are temporary (largely seasonal), shallow, groundwater-fed lakes surrounded by a rocky rim and lined with boulder clay, which are replenished and drained through discrete openings connected with the water table. Europe's largest turlough is found at Carran in the central Burren.

Karst areas such as the Burren are particularly sensitive to pollution because of the thin (or absent) soil cover that provides minimal attenuation of pollutants. Also, there is little attenuation by the rock itself due to the speed of water flow, which can reach over 100m/hr. A study by Drew et al. (1995) concluded that 'short of operating perfect management practices, such an environment does not possess the resilience to survive modern rural activities of the type described in this study'. As a result, particular care has to be taken in the control of pollutants, agricultural and domestic, generated in the Burren.