Mt. Guna is a Miocene shield volcano on the Ethiopian plateau. The surface waters are drained radially, and through deep percolation feed a number of springs at the interface between the volcanic tuffs of Mt. Guna and the underlying Ashangi basalt. This study makes a reconstruction of hydro (geo) logical and geomorphological changes, and allows to predict future scenarios on similar Miocene volcanoes in the Highlands.