examples:
1. Caves
Caves are carved out over thousands of years by flowing water, but that activity can be sped up by carbonic acid present in the water. As fresh water leeches through the rock and soil and drips through cracks, it gathers calcium carbide from the rock. When this water moves through a rock, the resulting carbonic acid erodes the rock until over time, a cave formation occurs.
2. River Banks
The banks of creeks and rivers erode over time as the water moves past it, carrying away sediment and depositing it elsewhere. The Colorado River, which flows through the Grand Canyon, drops as much as an estimated 100,000 cubic yards of sediment in Lake Powell each year. This type of soil erosion often comes as a result of water moving past the banks or walls of a river bed. Also, rocks in the river itself can be worn down and smoothed due to the constant rolling or "tumbling" motion the moving water causes.
3. Cracks in Rocks
Through a process known as exfoliation, rocks can erode due to nothing more powerful than energy from the sun. When rocks are heated quickly by the sun, the rock expands quickly. This rapid expansion can cause small cracks to form, cracks which make the rock vulnerable to wind and water erosion.
