Why does the Loess Plateau flow to the Yellow River?

The soil on the Loess Plateau is very loose. After the Yellow River flows through the Loess Plateau, a lot of sediment is impacted by the Yellow River water, and the sediment is washed into the Yellow River, so there is a lot of sediment in the Yellow River. The flow direction is from north to south. I'm talking about the lower Yellow River. If you want to go upstream, it is from southwest to northeast.