1) Waterfalls also create erosion. Soft rock erodes, leaving a hard ledge that it washes over. Rocks fall over the waterfall and swirl around in the pool, creating more erosion. The process is repeated, and the waterfall retreats, leaving a gorge behind.
2) Coastal erosion from oceans is always occurring. An eroding beach can lose several feet of sand in one year. In California, waves and rain create mudslides that take down houses by the dozen.
