After heavy rain, silt-laden, muddy flood water
pours into a pond (rear) and then exits (front).

The same pond after a catastrophic flooding event.
So much silt has been left by the flood water, that most of the pond
has been completely filled up with sediment.

To retain this area as a pond, most of the deposited silt had to be removed.

If the sediment had been left, succession would rapidly have taken place.
Marsh plants would have colonized the newly deposited substrate and succession would have continued from this point.