* Water Flow: Water in a river flows faster on the outside of a curve due to centrifugal force. This faster flow has more energy and can carry larger sediment particles like sand.
* Erosion and Deposition: The faster flow on the outside of the curve erodes the riverbank, carrying the sand downstream. As the water slows down on the inside of the curve, it loses energy and deposits the sand, building up a sandbar.
So, the outside of the curve is where you'll find the most sand deposition.