Gangotri Glacier lies on the northern side of Mandani Parbat from the snout of Gangotri Glacier comes out Bhagirathi River one of the main tributaries of river Ganga. On the south western side lies Mandani Glacier, from there comes out Mandani river after a short run it merges with Kali Ganga at Jalmalla near Kalimath which later joins Mandakini River below Naryankoti near Gupt Kashi later it joins Alaknanda River at Rudra Prayag which ultimately joins Bhagirathi River the other main tributaries of river Ganga at Dev Prayag and became Ganga there after.