Hydrology is the study of water, and hydrologists are scientists who study where water travels, how it moves from place to place, and what factors influence earth’s water supply and water quality along the way. In short, hydrologists study the water cycle in an effort to understand how precipitation, infiltration, evaporation, and transpiration all occur to keep water moving from our atmosphere, into the oceans, and back to the atmosphere again.
It is important to understand that water is continually present and cycling on our planet, and processes such as evaporation, condensation, precipitation, transpiration, infiltration, etc. keep water moving between the earth and atmosphere. While water is plentiful on the planet, in many places, the distribution and quality of water are impaired for human consumption.
Roughly 97.2% of earth’s surface is covered by ocean water, and the remaining 2.8% are terrestrial areas. Over 75% of the water found in these terrestrial areas is locked in glaciers or is too salty for consumption. About 1% of the world’s total water supply is available as fresh water, and most of that is groundwater.
The flow of water in the aquifer and through limestone passages can influence what organisms are able to survive in these habitats. Sometimes, such as in narrow tubular conduits, the flow of water (or discharge) is significant and generates a rapid current which may make it inhospitable for some organisms that can’t adequately adhere to the bedrock. This movement of water through the rock also contributes to cave formation, or speleogenesis. Areas with high flow and a high salt content are typically where the dissolution of limestone occurs most rapidly.
Alternately, areas with slow current accumulate silt and sediment that is transported through the system. For divers, navigating through these areas requires experience and finesse to prevent stirring up silt, preserve cave formations, protect habitat, and to maintain visibility.