 The Lebu is formed from the confluence of the Riachuelos of Curanilahue and Pilpilco that meet at the base of that mountain range.From the confluence it continues to the west, widening with the flow of the Riachuelos of Quilañanco and Curihuillín, and with several streams that join it from the wooded heights on both of its banks.It goes on to empty into the Pacific Ocean at 37° 36' Lat.