When the gradient of a river channel changes from a steep to a gentle angle, the main activity of the river will be
Answer Details
When the gradient of a river channel changes from a steep to a gentle angle, the main activity of the river will be "Depositing".
Explanation:
When a river flows down a steep gradient, it has a lot of energy, which it uses to erode the channel and transport the eroded material downstream. This results in a V-shaped valley and a lot of erosion happening.
However, when the gradient of the river channel changes to a gentle angle, the river loses some of its energy and begins to slow down. The eroded material it was transporting starts to settle out, and the river begins to deposit the sediment in the form of sand, silt, and clay particles. Over time, the river builds up its bed and banks, creating a wider and more shallow channel.
This process is called deposition, and it is the main activity of a river when it reaches a more gentle gradient. As the river continues to deposit sediment, it may form features such as sandbars, point bars, and levees.
In summary, when a river's gradient changes from a steep to a gentle angle, the main activity of the river becomes "Depositing" the sediment it has eroded.