Today the water course is marked by a stream that flows out of Malham Tarn north of the cove. It goes underground at 'Water Sinks' about before the top of the cove. Another stream named Malham Beck emerges from a cave at the bottom of the cove. The two streams were once thought to be one and the same, but experiments with dyes have shown that they are two separate waterways that go underground at different places. Their paths cross without mixing behind the limestone cliff, re-emerging a few miles apart. The experiments show that there is a complex system of caves and tunnels in the limestone cliff. The system is estimated to be about 50,000 years old. Cave divers, entering the system through the cave at the base of the cove, have so far explored about .