Sump (cave)
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A sump, or siphon, is a passage in a cave that is submerged under water.[1] A sump may be static, with no inward or outward flow, or active, with continuous through-flow. Static sumps may also be connected underwater to active stream passage. When short in length, a sump may be called a duck, however this can also refer to a section or passage with some (minimal) airspace above the water.
Depending on hydrological factors specific to a cave – such as the sea tide, changes in river flow, or the relationship with the local water table – sumps and ducks may fluctuate in water level and depth (and sometimes in length, due to the shape of adjacent passage).
Exploration past a sump
Diving
Short sumps may be passed simply by holding one's breath while ducking through the submerged section (for example, Sump 1 in Swildon's Hole). This is known as "free diving" and can only be attempted if the sump is known to be short and not technically difficult (e.g. constricted or requiring navigation). Longer and more technically difficult sumps can only be passed by cave diving (as happened repeatedly in the exploration of Krubera Cave).
Draining
When practical, a sump can also be drained using buckets, pumps or
Some manuals also mention the use of
See also
- Phreatic zone – Zone in an aquifer below the water table
References
- ISBN 9780128141250. Retrieved 18 April 2023.