Rivers will change the terrain, what will take away the soil on both sides of the river and what will fill the low-lying terrain?
In the process of flowing, the riverbed is destroyed by its own power and sediment, and the process of deepening, widening and lengthening is called river erosion. River siltation refers to the process that sediment, gravel and other substances carried by the river exceed the carrying capacity of the river and gradually deposit under the action of gravity. River sediments become alluvium, usually mechanical debris, such as sediments and gravel.
The role of rivers:
Rivers also have a great influence on the geographical environment. Rivers are an indispensable part of the earth's water cycle. Inland rivers transport water from mountains to the bottom of inland basins or lakes to realize small water circulation. The outflow river brings a lot of water from land to sea, which makes up for the evaporation loss of seawater and realizes the great cycle of water circulation. At the same time, heat and minerals are also transported with water.
North-south rivers send high-temperature water to high latitudes, or conversely, they can adjust the temperature in the basin. However, the migration of solid matter with rivers makes the high places on the surface level off and the low places filled up. Therefore, the river is not only the creator of mountain landscape, but also the creator of alluvial plains, large and small, and the salt accumulator in inland and ocean basins.