Musannaf Ibn Abi Shaybah 31006 — Book of the Judgments

Tha'labah bin Abi Malik said that the Messenger of Allah (peace and blessings be upon him) ruled concerning Mahzur, which is a valley of Banu Qurayzah, that the water is to be held back up to the ankles, and that those higher up must not hold it back from those lower down beyond that.