When I wrote that, I had in mind something like, Ethiopia currently draws say 2 Gm[SUP]3[/SUP]/yr (billion cubic meters per year) of water and the rest is for Sudan and Egypt, so Ethiopia would have to reduce its own consumption to 1 Gm[SUP]3[/SUP]/yr to fill the reservoir the difference of 1 Gm[SUP]3[/SUP]/yr. But it turns out, apparently Ethiopia had signed away their sovereign right to control the river a hundred years ago…
~Max