Why do rivers make sinusoidal patterns?”
There are four separate types of rivers: Straight, Braided, Anastomosing, and Meandering. What dictates the difference between these is the local energy of the river system through the gradient, the vegetation, and the amount of both bed and suspended sediment load. On slopes that are greater than .1 degrees the rivers are generally braided or straight because of the higher gravitational component results in higher water velocity and thus greater energy. I will assume for the sake of this answer that you are referring to a meandering river structure when you say ‘sinusoidal’. Meandering rivers are created in low energy plains with waters that are full of sediment. They do not begin as meandering. At the beginning of the creation of the system the river has a form that is primarily dictated by the local topography. Even if the banks are parallel, the thalweg, or deepest part of the channel, may not be. Meanders are created by the thalweg approaching the bank, at this point, the water wi
