This is a vertical hanging scroll of a waterfall by modern painter Byeon Gwan-sik.

About Byeon Gwan-sik (1899-1976):
Byeon was a renowned modern Korean painter. His penname is Sojung and is the grandson of Jo Seok-jin. Byeon Kwang Sik, alsong with Yi Sang beom was the leading master of traditional ink painting during the 1950s and 1960s.