Koteshwar lies in between two glaciers. On the eastern side lies Swetvarn Glacier and on the western side lies Thelu Glacier. Both these glaciers join Raktavarn Glacier on the south. Finaly Raktvarn drain itself at Gangotri Glacier near Gomukh from there emerges Bhagirathi River one of the main tributaries of river Ganga. River Bhagirathi later joins Alaknanda River At Dev Pryag and became Ganga there after.