sandbar

There is a sandbar stretching across the mouth of the river that does little to effect the flow of the fresh, swift river, but discourages the return of the heavier, salty water from the ocean. This natural barrier is responsible for preserving the current environment in the village, as an inflow of salty sea water would kill many of the plants in the Village. It also forms a natural barrier to infiltration, as gills that function in the salt level on one side of the sandbar would not be likely to function properly on the other, and the infiltrators would have to surface for air.

sandbar

Sawagakure TheJ