In a recent episode of Blue Sky Science, Faith Fitzpatrick (USGS) discussed how waterfalls are made and how long they last.
Blue Sky Science, a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research, finds local experts to answer science-related questions submitted by the public at the University of Madison Discovery Building in Madison, Wis.
USGS.gov
https://www.usgs.gov/center-news/how-are-waterfalls-made