Short answer. Yes, but not for long. Where a current carries away a known portion of your land onto another estate, Article 459 leaves ownership with you on one condition — that you remove it within two years. Let the two years pass and the soil goes with the land it landed on.
What the law says
Whenever the current of a river, creek or torrent segregates from an estate on its bank a known portion of land and transfers it to another estate, the owner of the land to which the segregated portion belonged retains the ownership of it, provided that he removes the same within two years.
Civil Code, Article 459 — Avulsion. Read the full provision →
What has to have happened
Article 459 applies where the current of a river, creek or torrent segregates from an estate on its bank a known portion of land and transfers it to another estate. The controlling word is known. The detached mass must be identifiable as having come from your property — a slab of bank with its soil, its crop, its trees still on it, recognisable when it comes to rest. If what moved was loose earth that merged indistinguishably into the ground downstream, there is nothing to identify and nothing to reclaim, whatever the volume that went.
The line between this and ordinary erosion
Land that a river takes from you slowly is simply gone, and land it builds up slowly on the far bank belongs to the owner there. That is the trade every riparian owner makes. This article is the exception for the sudden case, where a single flood does in a night what a current would take a generation to do. Because the event is visible and the portion identifiable, the law refuses to let a neighbour keep a windfall he did nothing to earn — but it also refuses to leave the question open forever, which is where the two years come from.
What the right actually entitles you to
It is a right to remove the soil, not a right to a piece of your neighbour's land. Nobody's boundary moves. You do not acquire the ground the detached portion is resting on, and you cannot insist that the survey lines be redrawn around where it stopped. Nor may you simply arrive with equipment; the removal happens on land belonging to someone else, so access has to be arranged with him, and damage caused in the course of taking your soil back is your responsibility. If nothing is done within two years, the portion is treated as belonging to the estate it joined.
The first things to do, because the clock is short
Fix the date. Photograph the break and the landed portion while both are fresh, from the ground and from the air if you can, and keep the weather reports and any barangay or municipal record of the flood. Have a surveyor plot what is missing against the technical description in your title, and identify the mass by what is still on it — the crop, the fence line, the trees. Then write to the neighbour promptly, ask for access, and keep the letter. Two years sounds generous and disappears quickly once the negotiation over access begins.