Why is the water in Yaan Dechang yellow?

According to Weather Network, Ya 'an, also known as Yucheng, is a prefecture-level city in Sichuan Province, located in the western edge of Sichuan Basin. Dechang County belongs to Liangshan Yi Autonomous Prefecture, Sichuan Province, and is located in the Anning River Basin. They are all close to the Yellow River, so they will be influenced by the Yellow River. The middle reaches of the Yellow River flows through the Loess Plateau, where soil erosion is serious, loess soil is loose, and there are many vertical cracks, so many substances are easily mixed into the river. Therefore, when there is a rainstorm, a large amount of sediment falls with the rain and flows into the Yellow River, making it the largest river with sediment concentration in the world.