What is the liability division for maintaining a shared water source like a river or canal?
General Chapter
Al-Mughni
Book of Reviving Dead Land
Primary text
When a river or canal is shared among a group, the responsibility for renting it out, closing a breach, or repairing its bank is divided among them according to their respective shares of ownership. If one party is closer to the head of the water source, all parties share the maintenance cost up to the point where that first person's direct involvement ends. Then, the remaining parties share the cost until the next shared point, and so on. This principle is held by Al-Shafi'i and reportedly by Abu Hanifa.
Supporting text
Abu Yusuf and Muhammad hold that all parties share the cost of maintaining the entire water source because they benefit from the whole system, even if the water passes the first user's land without irrigating it. Furthermore, if there is excess water requiring an outlet, the cost of maintaining that outlet falls upon all beneficiaries, as they share the need for it, similar to the source itself.