Weathering a mechanical or chemical surface process that break rock into smaller and smaller pieces Erosion the transportation of materials or sediment by natural forces

Deposition the dropping or settling of sediment carried by an agent of erosion Sediment small particles of materials from rocks or organisms moved by agents of erosion

Watershed an area of land where surface water converges into a single point and joins another body of water Groundwater water located beneath the Earth’s surface in soil pore spaces and in the fractures of rock formations

Surface Water water that is located above the ground Runoff water that moves across the surface of the land and enters streams

Pollution man-made substances that make water dirty and unsafe for use