RiversRiversWaterfalls, Plunge pools & Waterfalls, Plunge pools &

gorgesgorges

By Sam & Callum (FEHS Geog Students 2009-

11)

Name The Name The waterfall!waterfall!

Angel FallsAngel Falls

Niagara FallsNiagara FallsVictoria FallsVictoria Falls

Iguaçu Iguaçu FallsFalls

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

WaterfallsWaterfalls

WaterfallsWaterfalls

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

Plunge PoolsPlunge Pools

GorgesGorges

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.

GorgesGorges

CASE  STUDYCASE  STUDY      

Victoria  FallsVictoria  Falls

Victoria Falls are  Victoria Falls are  situated on the Zambezi river in Zsituated on the Zambezi river in Z

imbabwe.  imbabwe.  

At 5600 feet  At 5600 feet  wide, and 328 feet deep, it is the  wide, and 328 feet deep, it is the  largest largest waterfallwaterfall in the world.   in the world.  

The majority of  The majority of  the rock is basalt, but near the  the rock is basalt, but near the 

falls is criss-falls is criss-crossed with traverse faults  crossed with traverse faults 

of softer material. The force of thof softer material. The force of the  e 

river is eroding these faults and friver is eroding these faults and forming  a gorge.  orming  a gorge.  

As well as being  As well as being  a great geological feature, the falla great geological feature, the fall

s  generate substantial income s  generate substantial income for Zimbabwefor Zimbabwe

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

Interesting Facts about Interesting Facts about WaterfallsWaterfalls

• 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

PlenaryPlenaryQ) What process causes Waterfalls, Plunge Pools and Gorges to Q) What process causes Waterfalls, Plunge Pools and Gorges to form?form?

A) ErosionA) Erosion

Q) What section of a river are waterfalls generally found? Upper, Q) What section of a river are waterfalls generally found? Upper, Middle or Lower?Middle or Lower?

A) Usually Upper but can be found in MiddleA) Usually Upper but can be found in Middle

Q) And finally, why does a waterfall gradually retreat?Q) And finally, why does a waterfall gradually retreat?(Explanation)(Explanation)

A) As the process of erosion continues to act upon the rocks and the 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 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 overhang is created, as these become too heavy they break off and fall so the waterfall gradually retreats upstream, this is what causes fall so the waterfall gradually retreats upstream, this is what causes long gorges such as the one in Victoria Fallslong gorges such as the one in Victoria Falls

Thank you for watching,Thank you for watching,