Waterfalls, plunge pools, and gorges are formed through the natural process of erosion. Waterfalls are typically found in the upper sections of rivers where fast moving water erodes away softer rock. As the waterfall erodes the rock over time, it carves out a deep plunge pool and gradually moves further upstream, leaving a gorge behind it. Victoria Falls on the Zambezi River in Zimbabwe is the largest waterfall in the world, formed as the river erodes cross faults of softer rock surrounded by harder basalt.

1. Rivers Waterfalls, Plunge pools & gorges By Sam & Callum (FEHS Geog Students 2009-11)

2. Name The waterfall! Angel Falls Niagara Falls Victoria Falls Iguaçu Falls

3. Waterfalls Waterfalls are a natural feature which are often found in the upper or sometimes middle sections of a river. They are formed by the process of erosion.

4. Waterfalls

5. Plunge Pools It is a stream pool, lake, or pond that is small in diameter, but deep. These are also caused by the process of erosion on soft rocks.

6. Plunge Pools

7. Gorges This image is of the amazing gorge in Victoria falls, Zimbabwe & Zambia! Most gorges are formed through water erosion. For example, waterfalls erode the rocks they fall over and the falls move gradually back - leaving a gorge behind them.

8. Gorges

9. CASE STUDY Victoria Falls Victoria Falls are situated on the Zambezi river in Zimbabwe. At 5600 feet wide, and 328 feet deep, it is the largest waterfall in the world. The majority of the rock is basalt, but near the falls is criss-crossed with traverse faults of softer material. The force of the river is eroding these faults and forming a gorge. As well as being a great geological feature, the falls generate substantial income for Zimbabwe

10. An amazing panoramic view from the Zambian side near the Knife-edge bridge

11. Interesting Facts about Waterfalls The tallest waterfall in the world is Angel Falls: it has a 3212ft (979m) drop. The widest waterfall in the world is Khone Falls: it is 6.7 miles (10.8 kilometers) wide There are 10 types of waterfalls: block, cascade, cataract, fan, horsetail, plunge, punchbowl, segmented, tiered and multi-step. 10,800m

12. Plenary Q) What process causes Waterfalls, Plunge Pools and Gorges to form? A) Erosion Q) What section of a river are waterfalls generally found? Upper, Middle or Lower? A) Usually Upper but can be found in Middle Q) And finally, why does a waterfall gradually retreat? (Explanation) A) As the process of erosion continues to act upon the rocks and the turbulent water at the bottom of the plunge pool erodes the cliff, an overhang is created, as these become too heavy they break off and fall so the waterfall gradually retreats upstream, this is what causes long gorges such as the one in Victoria Falls

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