What is "chisone"

The Chisone (in Piedmontese Chison or Cleson) is a Italian torrent, which runs through Pragelato, Fenestrelle, Perosa Argentina and Pinerolo in the Province of Turin. It is a tributary of the Pellice, which in turn is a tributary of the Po River. Although classified as a torrent, there is no period of the year at which the Chisone runs dry.