How Alluvion Works

Alluvion is a form of accession. Accession is a method of increasing real estate or land value by making improvements and additions through paid labor. Or, as it is in the case of alluvion, accession can also happen through natural forces. Alluvion, in particular, is a special type of accession. This addition of land, and therefore increase in value, happens at no cost to the landowner. However, alluvion is largely unpredictable, can end up being quite damaging to a property, and takes years to notice. Also, reasonably, alluvion requires the owned land to be on the shore of an active body of water—a stream, river, or lake. These bodies of water should present new problems. These problems include the threat of floods and, ironically, the erosion of the land.

If alluvion occurs and is substantial enough to influence land value, there are laws and rules to help a landowner navigate the situation. Suppose two adjacent landowners, both on the same shore of a river or stream, acquire new land through alluvion. In that case, both parties are legally obligated to split the new land based on previous property boundaries to prevent dispute or conflict. If there are disagreements on who the new land belongs to, the two parties may contact a real-estate lawyer or advisor to make a verdict.

Example of Alluvion

Imagine that you just bought a house on the bank of the Mississippi River. The portion of the river at the back of your house is at the end of the active portion of the river, making it the perfect place for silt, sediment, and other materials to be deposited. After many years of living and owning the house, you notice that the size of your backyard has increased. With a little research, you come to the conclusion that alluvion has added sediment and land to your property.

This accession results in a small increase in the value of your land. Eventually, you decide to talk to your neighbor about it, as they live on the bank of the river as well. They own the plot of land right next to yours and your extra land is snug against it. Your neighbor and you both decide to share the new land using the town zoning boundaries. Unfortunately, you and your neighbor disagree on how to interpret the property boundaries and how you should apply them to the new land.

Even though you disagree with each other, there is no hostility. You both decide to contact a real-estate advisor instead of a lawyer to get official guidance on how to divide the land. When you do, the land is equitably split between the two of you at the advisor's discretion, and both of you are content with the division.