Summary of site:
In the course of exploration of local water resources in the mid-1980s it was realised that Lough Lee had no outflow channel but drained instead into a sinkhole at its western end. This was surprising since the bedrock of the area is Mullaghmore Sandstone, a rock type not normally associated with karst development. Work revealed that the water draining into the sink re-emerged at Rapid Spring, a large but impenetrable rising. Later engineering work to deepen Lough Lee has modified the sink and Rapid Spring is now an intake for local water supply.
In Binnawooda townland the Fairy Water Rising, below a 5 m high sandstone scarp is believed to be fed by streams entering an extensive series of dolines (solution or collapse hollows) 200 m to the south.
The strong flow at Rapid Spring suggests a single conduit linking it directly to Lough Lee and the predominance of calcite cementing the sand grains of the Mullaghmore Sandstone is thought to explain the development of the local karst. The Binnawooda doline field and spring have importance as the only surviving area in Northern Ireland where karst is developed on sandstone.