Report from Nauticapedia
We see lakes and decreasing in area, as more land is created from the soil washed from the upland. Riverbanks too become wider and upland owners gain ownership (they can have the added land titled. In the process, the waterway gets narrower, and common sense dictates that less volume of water can pass through hence this is flooding.
In my town, In Cainta, Pasig, in Marikina, I know for a fact, that accretions in rivers has been a cause of flooding. Laguna lakes area has likewise been decreased because of accretion and reclamation projects. The volume of the lake is considereably reduced.
Distinction is made between avulsion and accretion: avulsion is sudden depositing of land (as maybe caused by a landslide or flood) vs accretion which is gradual. Avulsion cant be titled to private individual
"Accretion is a term that refers to the increase in the mass of land adjacent to a body of water, whereas erosion is a decrease in such landmass. Accretion of land is of two types: (1) by alluvion, the process of sand or soil washing up so as to form firm ground; and (2) by dereliction, as when the sea shrinks below the usual watermark, exposing more land. The addition (or loss) of new land to an adjacent upland parcel by the action of water can be sudden, and is referred to in property law as an avulsion.
An accretion’s primary characteristic, on the other hand, is that the action of water in a lake, sea or river results in the gradual and imperceptible loss or addition of land. This distinction is important, as under common law the upland owner acquires any land that may accrete to waterfront land already in their possession, while in the case of an avulsion - such as a massive deposit of sediment brought into an estuary by a landslide event- the land remains in the ownership of the Crown. Putting out a breakwater to deliberately catch water-borne sediments would interfere with natural processes, as would depositing fill. Land created in this way would also not qualify as an accretion. There are instances, however, where land created inadvertently and slowly as a result of a man-made structure may be deemed an accretion."
