1. Accretion is the process by which soil is gradually deposited along river banks, increasing the land area. For accretion to occur, the deposit must be gradual and imperceptible and caused by the river current. The owner of the adjacent land gains ownership of the accreted land.
2. Avulsion is the sudden removal of land by water. If the detached land remains identifiable, ownership is not changed. The owner must remove the land within 2 years.
3. Under the Torrens system, titles are presumed valid and indefeasible against claims not annotated on the title. However, ownership can still be disputed and registration does not necessarily prove ownership.