Reports that Ethiopia has begun the second and much larger filling of a Nile dam it is building are based on a rainfall-related technicality that left Addis Ababa no choice but to hold back water behind the giant structure, experts told <em>The National </em>on Wednesday. The Grand Ethiopian Renaissance Dam, which Ethiopia says is 80 per cent complete, was not ready for the second filling, which Ethiopia said will involve the storage of 13.5 billion cubic metres of water during the peak of the flood season in July and August. Ethiopia has denied <a href="https://www.thenationalnews.com/mena/ethiopia-began-second-filling-of-gerd-dam-in-early-may-says-sudan-official-1.1229754">reports that a second filling began earlier this month</a>. Egypt, which says the $5-billion dam will significantly reduce its vital share of the Nile's water, has not commented either. The reports may have been inspired by the storage of an “insignificant” amount of water behind the dam earlier this month due to heavier than usual rainfall, said Hany Raslan, a senior Africa expert at Egypt’s Al Ahram Centre for Political and Strategic Studies who closely monitors the dam. “We may be talking about 100-200 million cubic metres of water.” Egypt and fellow downstream nation Sudan have repeatedly warned Ethiopia against making good on its threat to go ahead with the second filling without first reaching an agreement with them on the dam’s operation and running. The latest round of talks between the three nations stalled in April, and fiery rhetoric and sabre rattling by all three have escalated the crisis since. Last year’s first filling involved 4.5 billion cubic metres of water, which did not impact Egypt, thanks to a bountiful flood. In contrast, Sudan complained the filling disrupted work at some water treatment facilities, leaving thousands of households without running water for days. The middle section of Ethiopia’s dam must be built up to 590 metres above sea level if 13.5 billion cubic metres were to be stored this summer, experts said. At the moment, the structure stands at 560 metres above sea level. “Work on the mid-section was scheduled to begin in March but did not start until May,” said Mr Raslan. "With the current rate of progress in construction, only half of the declared amount of water will be stored in July and August," he told <em>The National</em>. Sudan’s Irrigation Ministry shot down the reports of the dam filling as inaccurate. “I have learned that that information is totally erroneous,” said Osama Abu Shanab, head of the media department in Sudan’s Irrigation Ministry. Commenting on a Reuters report that said Ethiopia began the second phase of filling its Grand Renaissance Dam in early May by holding back water to fill its reservoir, he told <em>The National</em>: "The actual filling has not taken place." The 6,450-megwatt hydropower project is being built on the Blue Nile, the river’s main tributary, about 20 kilometres from the Sudanese border. Ethiopia says the dam will lift millions out of poverty and will benefit neighbouring nations to which it hopes to export electricity. The reports on a second filling coincided with the start on Wednesday of six days of war games between Sudan and Egypt involving commandos, aircraft and air defences. The joint drills, the latest in a series by the two countries, are codenamed “Guardians of the Nile.” They are aimed at “strengthening bilateral relations and unifying methods on dealing with threats that both countries are expected to face," Sudan's state news agency SUNA reported late on Tuesday. Egyptian forces and hardware arrived in Sudan by air and sea over the weekend. Egypt’s President Abdel Fattah El Sisi warned in March that his country’s share of the Nile waters was “untouchable” and that “unimaginable instability” would prevail in the region if Egypt is denied a drop of its share of the Nile’s water. Egypt relies on the Nile for more than 90 per cent of its fresh water needs.