Estavelle

In karst geology, estavelle is a ground orifice which, depending on weather conditions and season, can serve either as a sink or as a source of fresh water.

References

• "Estavelle". http://www.showcaves.com/english/explain/Karst/Estavelle.html. 
• Petar T. Milanović (2004). Water resources engineering in karst. CRC Press. pp. 211–212. ISBN 9781566706711. http://books.google.com/books?id=DLyh1BIm9owC&pg=PA211#v=onepage&q=&f=false.