![](https://gualalariver.org/wp-content/uploads/2024/11/2024-11-15-GR-estuary-Jeanne-Jackson-800x600.jpg)
Note: When the river mouth is closed by the sandbar, the lower part of the river is called a lagoon. When the mouth is open to the ocean, it is called an estuary.
Note: When the river mouth is closed by the sandbar, the lower part of the river is called a lagoon. When the mouth is open to the ocean, it is called an estuary.