Amr bin Shu'ayb narrates from his father, from his grandfather (Sayyiduna Abdullah bin Amr, may Allah be pleased with them both), that the Messenger of Allah (peace and blessings be upon him) gave judgement concerning the torrent channel of Mahzur: "The water is to be held until it reaches the ankles, then the upper one sends it on to the lower one."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب إحياء الموات / 11858