A sandy underwater shoal at the mouth of a river, formed as a result of sedimentation of river and sea loads. The bar separates the river mouth from the sea.

A river junction bar is located at the mouth of a river, the place where the river flows into the sea.

The sea junction bar is located at the junction of river and sea currents.

A chalk or silt that forms near the mouths of rivers and prevents river boats from going out to sea and back. It is well known that a strong current in a river can reach great depths; but when the water reaches the sea in calm weather and meets a motionless mass of sea water, the current, which immediately spreads out in all directions, weakens - and its effect on the bottom is completely destroyed, because fresh water, being lighter than salt water, is deposited on top. From then on, the sediment carried by the current, which loses its speed, is deposited on the bottom, forming what is known as a ridge. The bars are formed not only by river sediment, but also by sediment carried along the coast by the action of waves and the tide.