Soil and water loss refers to the damage and loss suffered by water and soil resources and land productivity under the action of external forces such as water power, gravity, and wind, including erosion of land surface and water loss, also known as soil and water loss. Unrealized economic activity is generated by the interweaving of each other. Based on the above definitions, Which of the following are not lost on the water:. ['Debris flow after a heavy rain somewhere.', 'Gradual desertification in some areas under strong winds.', 'Rocks become gravel after long-term weathering.', 'The Yellow River brings a large amount of sediment to the lower reaches of the plateau.']