Egypt made headlines recently by threatening to invade Ethiopia if the Ethiopians did not stop building a hydroelectric dam on the “Blue Nile.” This dam would not decrease the flow of water downstream to Egypt (where most of it would be used for irrigation, as has been the case for thousands of years). Egypt ignored that fact. What did bother Egyptian politicians a great deal was that most of the Nile water comes from Ethiopia (via the “Blue Nile”). The other 20 percent comes from the White Nile that flows through Sudan. The White and Blue Nile meet at Khartoum in Sudan to form the Nile, which flows downhill to Egypt and the Mediterranean.
Egypt has long understood that most of the water came from the Blue Nile and Ethiopia but has never been able to seize control of Ethiopia or threaten Ethiopia as it had done with Sudan for thousands of years. Some serious attempts to invade Ethiopia were made in the 19th century but all failed. Italy also made several attempts and finally succeeded in the 1930s. After World War II began (in 1939) Britain came to the aid of Ethiopia and forced the Italians to withdraw. Ethiopia is the only African nation (and a major one at that) that was never colonized. Moreover, the Ethiopians are largely Christian and have long resisted aggression by Moslem nations.
Ethiopia has long resisted Egyptian pressure and threats over building new dams and other water projects on the Blue Nile River. Ethiopia, Uganda, Rwanda, and Tanzania, all containing sources of the Nile, recently announced joint action to obtain a more equitable share of Nile River water. Ethiopia believes that Egypt and Sudan claim too much water and base their claims on colonial-era agreements that are no longer valid. The main treaty was created in 1929, but few of these treaties involved Ethiopia because Ethiopia was never under colonial control and never recognized any foreign nation as having any claims on its water. Worse for Egypt, Sudan (which has been conquered many times by Egypt, and actually ruled Egypt for over a century in ancient times) backs Ethiopia in these water matters. Most Egyptians seem to understand the military superiority of Ethiopia and the inability of Egypt to back up its threats. Nevertheless the Egyptian public feels better when their government acts aggressively about protecting the Nile water flow.