وَنَبِّئْهُمْ أَنَّ ٱلْمَآءَ قِسْمَةٌۢ بَيْنَهُمْ ۖ كُلُّ شِرْبٍ مُّحْتَضَرٌ

And inform them that the water is shared between them; every share of the water shall be regulated.