by paul » Jun 19, 2007 6:49 am
Here is a definition I found:
"In caves a sump is a section of flooded passage. This may be a perched sump, probably quite short, within a vadose cave and created by a local reverse passage gradient. Alternatively it may be a major feature, where a cave passage descends below the regional water table into the phreas, as is common at the lower end of many cave systems. Some short sumps can be dived without the use of breathing apparatus (SCUBA), but most are restricted to exploration by cave divers. Logistics are a barrier to endless sump penetrations, but some have now been explored for many kilometres in length, notably in Cocklebiddy Cave, Australia, the Nohoch Nab Chich and other great flooded systems in Mexico's Yucatan, and behind Keld Head in Yorkshire. "