Point Bar

A point bar is a crescent shaped depositional landform built from sand, gravel and other alluvium that accumulates on the inside bend of a river or stream. It forms because water flowing around a bend cannot travel in a straight line: a secondary current moves across the streambed toward the inside of the curve, where the radius of the bend is smallest, sweeping sediment along with it. This happens because water pressure is slightly higher against the outer, concave bank than against the inner, convex bank, and that pressure difference pushes the slower moving water near the streambed, along with the sediment it carries, up the shallow slope of the point bar. The result is a well sorted deposit with a gentle slope near the water, a feature that also makes point bars a common spot for boaters to stop, despite the danger they can pose during floods.