The $4.6bn Grand Ethiopian Renaissance Dam (GERD) seen near Guba in Ethiopia [Eduardo Soteras/AFP]

Move comes as latest round of talks between Egypt, Sudan and Ethiopia on the contentious dam ended with no agreement.

Ethiopia started filling Grand Renaissance, a giant hydroelectric dam it is building on the Blue Nile, its water minister said on Wednesday after talks with Sudan and Egypt over the structure became deadlocked.

Ethiopia says the colossal dam offers a critical opportunity to pull millions of its nearly 110 million citizens out of poverty. The project is the centrepiece of Ethiopia’s bid to become Africa’s biggest power exporter.

“The construction of the dam and the filling of the water go hand in hand,” Water Minister Seleshi Bekele said in comments broadcast on television. “The filling of the dam doesn’t need to wait until the completion of the dam.”

The water level increased from 525 metres (1,720 feet) to 560 metres (1,840 feet), said Bekele.

Interactive: Saving the Nile

Egypt has asked Ethiopia for urgent clarification on the matter, its foreign ministry said. The Blue Nile is a tributary of the Nile from which Egypt gets 90 percent of its fresh water.

Cairo told the United Nations last month it faces an “existential threat” from the hydroelectric dam.

Sudan’s government, meanwhile, said water levels on the Blue Nile had declined by 90 million cubic metres per day after Ethiopia started filling the dam on its side of the border.

Sudan rejects unilateral actions taken by any party as negotiating efforts continue between the two countries and Egypt, its irrigation ministry said in a statement.

“It was evident from the flow metres in the Dimim border station with Ethiopia that there is a retreat in the water levels … confirming the closure of the gates of the Renaissance Dam,” it said.

‘Sovereign right’

Relying on the Nile for more than 90 percent of its water supply and already facing high water stress, Egypt fears a devastating effect on its population of 100 million.

In June, Minister of Foreign Affairs Sameh Shoukry warned conflict could erupt if the UN fails to intervene, as the dam endangers the lives of 150 million Egyptians and Sudanese.

Ahmed Soliman, a research fellow with Chatham House, noted Egypt’s water requirements already outpace its availability.

“What we have in Egypt is a significant gap between the amount of water they produce and the amount of water they consume. And with a rapidly growing population of more than 100 million, it points to this problem only getting worse,” Soliman told Al Jazeera.

Awol Allo, from Keele University in the UK, said Egypt is demanding adherence to a 1959 water treaty, signed between Cairo and Khartoum, that gave Egypt the lion’s share of the Nile’s annual flow.

Ethiopia was not included in that colonial-era treaty.

“I think Ethiopia has been negotiating for a considerable amount of time in good faith to reach a settlement on this issue, but the Egyptians insist on the 1959 treaty as the starting point,” Allo told Al Jazeera.

“There is strong public support for the Ethiopian government to get on with the dam. The majority of Ethiopians are on the same page – that is it is their sovereign right to fill and open the dam.”

Africa’s largest dam

Cairo was anxious to secure a legally binding deal that would guarantee minimum flows and a mechanism for resolving disputes before the dam started operating.

Sudan stands to benefit from the project through access to cheap electricity and reduced flooding, but it has also raised fears over the dam’s operation.

The dam is being built 15km (nine miles) from the border with Sudan on the Blue Nile, the source of most of the Nile’s waters.

The latest round of negotiations between Egypt, Sudan and Ethiopia over the contentious dam ended with no agreement on Tuesday, according to Egyptian and Sudanese officials.

The failure sank modest hopes the three countries could resolve their differences and sign an agreement on the dam’s operation before Ethiopia began to fill the $4.6bn Grand Ethiopian Renaissance Dam (GERD), set to be Africa’s largest.

Ethiopia says more than 60 percent of the country is dry land with no sustaining water resources, while Egypt is endowed with groundwater and has access to seawater that could be desalinated.

Addis Ababa had previously pledged to start storing water in the dam’s vast reservoir at the start of the wet season in July, when rains flood the Blue Nile.

Source: Al Jazeera News