Why is this Nile dam so controversial?

One dam. Three countries. A big headache. Ethiopia couldn’t be more proud of it, but the Grand Renaissance Dam has proven controversial. The dam is being built on the Blue Nile River. When complete, it will be Africa's biggest hydroelectric power plant. Problem is: both Egypt and Sudan fear the dam will limit their access to water. Ethiopia, on the other hand, says the project is vital to its development. Negotiations between all three countries are going nowhere. So, how did we get there? And how can the deadlock ever be broken? Hosted by Alan Kasujja (@Kasujja on Twitter) #AfricaDaily