Following a two-day meeting of Egypt, Ethiopia and Sudan's foreign and water ministers, Khartoum's chief diplomat, Ibrahim Ghandour, said firms BRL and Artelia had been tapped for the work.
Sudanese Water and Electricity Minister Moutaz Moussa Salim told AFP that "BRL will carry out 70 percent of the study, and Artelia the rest."
They will begin work in February and take six months to complete it, Salim said, adding that their conclusions would be accepted by the three countries.
Egypt draws about 90 per cent of its water from the Nile, which runs from Khartoum to the south, where the Blue and White Nile rivers converge. It is concerned the dam could negatively affect the supply.
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Under treaties signed in 1929 and 1959, Egypt and Sudan together are entitled to use 87 per cent of the Nile's waters.
At a meeting in Khartoum with Egyptian President Abdel Fattah al-Sisi and his Sudanese counterpart Omar al-Bashir, Ethiopian Prime Minister Hailemariam Desalegn assured them the project would "not harm our three countries, and in particular the Egyptian people".