causes:
Water flowing over Earth's surface or underground causes erosion and deposition. Water flowing over a steeper slope moves faster and causes more erosion. How water transports particles depends on their size. When water slows down, it starts depositing sediment, starting with the largest particles first.
effects:
Deposition changes the shape of the land. Erosion, weathering, and deposition are at work everywhere on Earth. Gravity pulls everything toward the center of Earth causing rock and other materials to move downhill.