“The Messenger of Allah ﷺ ruled concerning the stream of Mahzur that the higher ground took precedence over the lower, so the higher ground should be irrigated until the water reached the ankles, then it should be released to those who were lower.  

قَضَى رَسُولُ اللَّهِ ﷺ فِي سَيْلِ مَهْزُورٍ الأَعْلَى فَوْقَ الأَسْفَلِ يَسْقِي الأَعْلَى إِلَى الْكَعْبَيْنِ ثُمَّ يُرْسِلُ إِلَى مَنْ هُوَ أَسْفَلُ مِنْهُ  

'Amr bin Shu'aib on his father's authority said that his grandfather told that the Messenger of Allah ﷺ decided regarding the stream al-Mahzur that its water should be held back till it reached the ankles, and that the upper waters should then be allowed to flow to the lower. (Using translation from Abū Dāʾūd 3639)   

أَنَّ رَسُولَ اللهِ ﷺ قَضَى فِي السَّيْلِ الْمَهْزُورِ أَنْ يُمْسَكَ حَتَّى يَبْلُغَ إِلَى الْكَعْبَيْنِ ثُمَّ يُرْسِلُ الْأَعْلَى عَلَى الْأَسْفَلِ