What is "Ihya' al-Mawat" (reviving dead land), and what are its rulings?

Wasteland is land that has no owner. It is owned by whoever revives it. Revival is achieved by enclosing it with a strong wall, or by digging a well and reaching its water, or by bringing water to it, or by damming water from it to make it suitable for cultivation. The definition of revival is subject to common practice (urf). The Imam may grant (iqta') wasteland to whoever revifies it, and it becomes owned by the one who revives it after the grant, not merely by the grant itself. The Imam may also reclaim it from someone who failed to revive it. Whoever precedes others to a permissible resource, such as hunting or gathering firewood, has a greater right to it. Permissible water is divided among people: the one at the higher elevation irrigates first, then releases the water to those below. If the water is privately owned, it is divided according to ownership. The Imam may designate a pasture as a protected area (hima) for public livestock, provided that this does not harm the Muslims.