One of the main source of sediment in flowing water is soil erosion.
Explanation:
Soil erosion is the washing away of top most layer of soil due to various reasons.
Agents of soil erosion are: wind, water, animals, ice or gravity.
Water is one of the biggest agent or cause of soil erosion. Water carry lots of energy in its motion. When water moves from any area it carries away topmost layer of soil with it. The soil that is being carried away by water is sediment.
When this water reach river, lake or any other water source, sediments carried by them enters that source of water. Sediment results in water pollution.
