The term 'circular water movement' refers to the phenomenon of eddies, which are small areas of rotating water that form in rivers, streams, and oceans. Eddies are created when a current of water is disrupted by an obstacle or a change in direction. They can range in size from a few centimeters to hundreds of meters in diameter and can last for minutes or even days. Eddies are important for transporting nutrients and sediment, and they can also be used to measure the speed and direction of currents.