was the first European explorer to determine that they were two separate rivers, and in 1882 proved false the rumor that these rivers flowed from the same mountain lake.

It is important as a boundary both in cultural and political terms. According to Dunlop, who explored the region in 1935, the river is where "the Christian church of the Oromo people gives place to the mosque, and the Oromo greeting to the universal Muslim politeness: