Is it permissible to enter into a lease contract (Ijarah) for digging wells, rivers, or canals?

Primary text

It is permissible to hire labor for digging wells, rivers, or canals because this constitutes a known benefit (*manfa'ah ma'lumah*), which is a benefit a person may volunteer to perform for another. Therefore, a lease contract concerning it is valid, similar to service contracts. The scope of work must be defined either by a specific period of time or by a specific quantity of work.