Two weeks ago, Ethiopia started filling the Grand Ethiopian Renaissance Dam on the upper Nile river, a $4.6 billion hydroelectric project that aims to bring electricity to tens of millions of energy-starved Ethiopians. Egypt and Sudan cried foul, warning that doing so too quickly will leave their farmers without enough water to irrigate crops. The main reservoir was filled in just a few days, a speed that Addis Ababa blamed on seasonal rains.
But this trilateral dispute is about more than just water — and even the US and China are getting involved. Why is the this dam such a big deal, and what happens next?