The Grand Ethiopian Renaissance Dam has been controversial to the three countries ever since its construction began in 2011.
It has been delayed by seven years, costing some $4 billion.
Egypt fears the dam will affect its water supply and has demanded a guarantee of at least 5.5 billion cubic metres a year.
Ethiopia, Sudan and Egypt have moved closer to formalising a water-sharing deal over the Nile after technical teams meeting in Khartoum drew up a draft agreement.
At the end of a consultative meeting on Thursday, the technical teams from the three countries said they had included observations reached when the countries’ ministers met in Washington two weeks ago.
It is now expected that the next round of discussions, due in Washington next week, could see a formal agreement signed on how to fill the Grand Renaissance Dam on the Blue Nile in Ethiopia, without affecting the needs of the riparian countries: Sudan and Egypt.
Muhammad Al-Sebaie, the spokesman for the Sudanese Ministry of Water Resources and Irrigation, said technical teams had pored over suggestions from all the three countries in an earlier January 13 meeting in Washington, under the auspices of the US Treasury and the World Bank. The Washington meeting is due on January 28.
Al-Sebaie said that there had been some form of “convergence” such as initially filling up to a significant portion of its height (the dam is 155 metres high), to ensure electricity generation for Ethiopia. Thereafter, the subsequent filling will depend on weather conditions and there would be a joint implementation committee to oversee when to suspend filling, reducing volumes or surging the flow.
The key pillars in the agreement, he said, will be how to fill up the dam in stages, during the months of July and August, and in September based on drought or rain conditions.
After the Washington meeting on January 15, ministers had agreed informally to this arrangement but officials said specifics needed to be thrashed out, including how to determine what constitutes severe droughts or sufficient rainfall.
The lead Sudanese negotiator Dr Saleh Hamad, said the teams have prepared proposals to be presented to the water ministers and foreign ministers of the three countries at their next meeting in Washington.
The Grand Ethiopian Renaissance Dam. the largest hydropower installation in Africa (on completion, it is estimated to produce up to 6,400 megawatt), has been controversial to the three countries ever since its construction began in 2011. It has been delayed by seven years, costing some $4 billion.
Since 2018, Ethiopian officials have spoken of fast-tracking its completion Ethiopian Prime Minister Abiy Ahmed had announced a need to start power production as soon as possible.
Ethiopian Minister of Water and Energy Seleshi Bekele had earlier this week addressed local contractors and representatives of the companies working in the dam's construction and demanded timelines for the launch of filling, which could take up to 15 years to fill.
Egypt, which relies on the Nile to meet most of its water needs, fears the dam will affect its water supply and has demanded a guarantee of at least 5.5 billion cubic metres a year.