Sump (cave)
Encyclopedia
Sump is a term used in caving
to describe a submerged passage in a cave. 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.
). 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 recent exploration of Krubera Cave).
s. Pumping the water away requires the inward flow of water into the sump to be less than the rate at which the pump empties it, as well as a suitable place to collect the emptied water. Upstream sumps have been successfully emptied using hoses to siphon water out of them, such as at the Sinkhole Dersios
during exploration in 2005. The water was sent deeper into the sinkhole
and the emptied sumps revealed virgin passage behind them. During a rescue from a beyond a downstream sump at Sarkhos Cave in 2002, water was pumped upstream into a dam
constructed a few metres above the flooded passage.
Some manuals also mention the use of explosives or other forms of force to empty sumps, but the ecological damage done to the fragile cave environment usually rules out the use of such methods.
Caving
Caving—also occasionally known as spelunking in the United States and potholing in the United Kingdom—is the recreational pastime of exploring wild cave systems...
to describe a submerged passage in a cave. 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.
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 HoleSwildon's Hole
Swildon's Hole is an extensive cave in Priddy, Somerset. At in length, it is the longest cave on the Mendip Hills. It has been found to be connected to Priddy Green Sink and forms part of the Priddy Caves Site of Special Scientific Interest ....
). 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
Cave diving
Cave diving is a type of technical diving in which specialized equipment is used to enable the exploration of caves which are at least partially filled with water. In the United Kingdom it is an extension of the more common sport of caving, and in the United States an extension of the more common...
(as happened repeatedly in the recent exploration of Krubera Cave).
Draining
When practical, a sump can also be drained using buckets, pumps or siphonSiphon
The word siphon is sometimes used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in the English language today, the word siphon usually refers to a tube in an inverted U shape which causes a liquid to flow uphill, above the surface of the reservoir,...
s. Pumping the water away requires the inward flow of water into the sump to be less than the rate at which the pump empties it, as well as a suitable place to collect the emptied water. Upstream sumps have been successfully emptied using hoses to siphon water out of them, such as at the Sinkhole Dersios
Sinkhole Dersios
The Dersios sinkhole is a sinkhole in Arcadia, Greece.The sinkhole, which has a depth of , has been known since antiquity and is located towards the north end of the plateau of Palaiochora at a height of 750 m above sea level on mount Parnon...
during exploration in 2005. The water was sent deeper into the sinkhole
Sinkhole
A sinkhole, also known as a sink, shake hole, swallow hole, swallet, doline or cenote, is a natural depression or hole in the Earth's surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone...
and the emptied sumps revealed virgin passage behind them. During a rescue from a beyond a downstream sump at Sarkhos Cave in 2002, water was pumped upstream into a dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
constructed a few metres above the flooded passage.
Some manuals also mention the use of explosives or other forms of force to empty sumps, but the ecological damage done to the fragile cave environment usually rules out the use of such methods.