Question

why do rivers change course and what happens then give an example​

Answer 1

Answer:

Mud deposit.

Explanation:

The rivers meander due to low gradient and discharge of water. On plain areas rivers tend to take the easiest way, the routes least resistant. The places that are easier cut or eroded will be the path the river takes. Due to some obstruction in the river bed, the speed of the flowing water between the two banks differs. Now the meandering process starts. On the faster side of the river, less sediment is deposited. And because the water is flowing faster, more erosion takes place and small curves are formed. At the slower side of the river, more sediment from erosion of the outer curve is deposited. This causes the meanders to grow larger and larger over time. The bend gets more and more pronounced with time. The slower side of the river will continue to get slower and the faster side gets faster. Thus more sediment gets deposited on the slow side and more erosion happens on the fast side.This process will continue until the curves are so sharp that the river will eventually cut through a curve, and re-establish a straight path. This is the time when the river changes its course. This most often occurs at the time of flooding, when the river has a higher discharge and more energy, and the ends join, the loop is cut-off from the main channel. The cut-off loop is called an oxbow lake. The low-lying area on either side of a river is called a floodplain. The floodplain is covered with water when the river overflows it banks during spring floods or periods of heavy rain. Sediment is deposited on the floodplain each time the river floods. Mud deposited on the floodplain can make the soil really good for agriculture.