Cave Definition

Generally, with a few exceptions, if a “void” is greater than 25 feet in combined length and depth, the ICS considers this a cave, otherwise it is a non-cave. The main exceptions would be a dug or man-made void such as a mine, or some shallow overhanging rock shelters, regardless of their widths or heights.

If an “entrance” is associated with a “non-cave”, then this field is used to better describe/classify the type of feature this non-cave is (most non-caves have only one entrance, if it has an entrance at all). Use “Less than 25’ Long” for features that are otherwise cave-like, other than their total combined length/depth is less than 25 feet. Use “Spring” to describe a feature with outflowing water and very little or no passage. It becomes a judgement call for a “spring” that may have some visible/accessible passage, but less than 25 feet (more than 25 feet would make it a cave).

Use “Sinkhole/Swallowhole” for a feature that has very little or no accessible passage, but may contain an inflowing drain. The ICS typically does not collect data on “generic” sinkholes or swallowhole, but interesting or dynamically changing sinkholes may be useful for hydrology research. Use “Sinking Stream” to designate a feature where water is in-flowing most of the year (occasionally in-flowing would be a swallowhole). Use “Rise/Rise Pool” in the situation where the source of the water is typically submerged and when there is flow, it is typically out-flowing. Use “Man-made/Mine” for a non-naturally formed feature. For a mine, it can exceed 25 feet, but should still classified as a non-cave. Note however, a man-made “dug” entrance into an otherwise natural cave that is longer than 25 feet should use one of the “cave” options rather than “man-made”. Use “Potential Dig” to describe a feature that looks like it has good potential (e.g., exposed rock, good airflow) and warrants additional attention/persuasion. Use this designation sparingly if one of the other non-cave descriptions also fit. Use “Other” only when none of the other non-cave options are appropriate. An explanation should be added to the comments in this situation.