Tags: Cave.
Upper Flood Swallet (grid reference ST50575576) which was originally known as Blackmoor Flood Swallet is a cave near Charterhouse in the carboniferous limestone of the Mendip Hills in Somerset England. The cave is part of the Cheddar Complex SSSI.The entrance was revealed in the Great Flood of 1968 giving the cave its name. It was dug consistently since then with breakthroughs occurring in 1971 1972 1985 and 2006.At of September 2008 it is over 3.5 km in length and around 125m deep.