How is priority determined when two parties have equal proximity to the head of a non-owned river or stream?
General Chapter
Al-Mughni
Book of Reviving Dead Land
Primary text
If two individuals are equally close to the beginning of the river, they must share the water if possible. If sharing is impossible, lots shall be cast (iqra') between them, and the one selected by the lot receives priority in full utilization of their right first. If the water is not sufficient for one person to take their full share without depriving the other entirely, the one who wins the lot takes their entitled portion first, and then leaves the remainder for the other, as they share the primary right to the water.
Supporting text
This priority granted by lot is for the order of fulfillment of the right, not the fundamental extent of the right itself, unlike the case of the higher versus the lower land user, where the lower user only has a right to what remains.