Reportedly at the direct instigation of President Donald Trump, the US State Department has ordered a suspension of aid to Ethiopia over its move to begin capturing water behind a controversial new mega-dam on the Blue Nile that has been opposed by Egypt and Sudan. A State Department spokesperson said the decision to "temporarily pause" some aid to Addis Ababa "reflects our concern about Ethiopia's unilateral decision to begin to fill the dam before an agreement and all necessary dam safety measures were in place." The statement said the decision was taken by Secretary of State Mike Pompeo "based on guidance from the president." The freeze could affect as much as $100 million in aid. The reservoir behind the Grand Ethiopian Renaissance Dam (GERD) began filling in July, over the protests of Egypt and Sudan. (Al Jazeera, Sept. 3; AP, Sept. 2)

Egypt, almost entirely dependent on the Nile for its freshwater supplies, is demanding a legally binding agreement that would guarantee minimum flows and a mechanism for resolving disputes before the dam begins operation. A draft deal was arrived at between Ethiopia, Egypt and Sudan in January after four days of US-brokered talks in Washington. The agreement called for the filling of the GERD to be executed in stages, and undertaken in a cooperative manner that takes into consideration the hydrological conditions of the Blue Nile and the potential impact on downstream reservoirs and communities. The filling was to take place during the wet season, from July to August.

But in July, Ethiopia began filling the reservoir before a formal pact had been finalized. "We will go ahead with the filling of the dam next month even if there's no agreement reached," Foreign Minister Gedu Andargachew said at the time, adding that "Egypt's insistence on controlling the river flow" was hampering progress in the talks.

Sudan responded with a letter to the UN Security Council, protesting Ethiopia's move. Among other factors, Khartoum's Water Ministry said that the filling of the GERD would "compromise the safety of Sudan's Roseires Dam and thus subject millions of people living downstream to great risk."

If the volume of water arriving from the Blue Nile decreases, particularly in time of drought, the turbines of the Roseires Dam could be damaged, the statement said. Conversely, increased pressure on the Roseires Dam due to sudden release from the GERD could surpasses its capacity and potentially cause its collapse. (Egypt Today, Aug. 4; Al Jazeera, June 26; Water Power & Dam Construction, Jan. 17)