Does a river turn over like lake does?

Yes, rivers also experience turnover events, although they may be less pronounced and less frequent compared to lakes. River turnovers occur when there is a significant change in the density of water throughout the river's cross-section, causing a vertical mixing of the water column.

Factors that can contribute to river turnovers include:

1. Changes in water temperature: During certain times of the year, particularly in spring or fall, the temperature of the river water can change rapidly. If the surface water becomes colder and denser, it can sink, pushing the warmer, less dense water upwards. This process is known as convective overturn.

2. Changes in sediment concentration: Rivers that carry a high sediment load can experience density-driven flows due to variations in sediment concentration. As sediment settles and accumulates on the riverbed, it can increase the density of the water near the bottom. This can cause a gravitational overturn, where the denser water sinks and is replaced by less dense water from the upper layers.

3. Tributary inflows: The confluence of a tributary with different water characteristics can also trigger a river turnover. If the tributary water has a significantly different temperature or sediment concentration compared to the main river, it can create density differences that lead to vertical mixing.

4. Wind-driven mixing: Strong wind events can generate surface currents and waves in rivers, which can help mix the water column. This is particularly common in wide and shallow rivers where the wind stress can impact the entire water depth.

5. Dam operations: Dams and reservoirs can influence the turnover dynamics of rivers downstream. The release of water from a dam can create changes in the river's flow velocity, temperature, and sediment concentration, which can trigger turnovers.

It's important to note that river turnovers may vary in intensity and frequency depending on the river's characteristics, such as its size, flow rate, and environmental conditions. Additionally, the presence of physical structures like dams, locks, or bends in the river can affect the occurrence and patterns of turnovers.