This is because more water is entering the dam site than the volume of water that can physically pass through the two open outlets in the dam wall (60-110 million cubic metres a day).
Sababtuna waxay tahay biyo ka badan ayaa galaya goobta biyo xireenka marka loo eego mugga biyaha mari kara labada marin ee furan ee gidaarka biyo xireenka (60-110 milyan oo mitir cubic maalintiiba)