Rivers

Question 1

what is a source

Answer 1

the origin of the river

Question 2

what is a tributary

Answer 2

a small stream joining a bigger stream

Question 3

what is a confluence

Answer 3

the place where two rivers join

Question 4

what is a waterfall

Answer 4

a step in a river

Question 5

what are rapids

Answer 5

a steep section of a river but not vertical

Question 6

what is a weir

Answer 6

a small dam to deepen the part of the river

Question 7

what is a flood plain

Answer 7

a flat area next to a river which can fload

Question 8

what is braiding

Answer 8

when the river divides and forms an island

Question 9

what is an oxbow lake

Answer 9

a cut off meander

Question 10

what is a levee

Answer 10

mud pilled up at the side of a river

Question 11

what is a mouth

Answer 11

the place where the river flows into the sea or lake

Question 12

what is an estuary

Answer 12

a signal river mouth

Question 13

what is a delta

Answer 13

multiple river mouths

Question 14

draw a long river profile

Answer 14

source
upper= erosion > deposition
middle= erosion = deposition
lower=erosion < deposition

Question 15

describe the process of a waterfall

Answer 15

For a waterfall to form there must be hard rock on top of soft rock at a cliff. Over time the soft rock will erode leaving a ledge of hard rock and a plunge pool beneath. With time the ledge will erode as well and eventually collapse, moving the waterfall upstream.

Question 16

draw a diagram of a waterfall

Answer 16

hard rock
soft rock
water

Question 17

describe the process of a oxbow lake

Answer 17

For an oxbow lake to form there must be a strongly curved meander. Over time the river will erode on the outside forming a narrow neck. With time it will cut off and with deposition the river will straighten and will leave an oxbow lake.

Question 18

draw a diagram of an oxbow lake

Answer 18

meander
river
oxbow lake

Question 19

what are the causes of flooding

Answer 19

1) heavy rain: if there is heavy rain the tree will not be able to intercept much water so it reaches the ground. There is not enough time for infiltration so the water leaves the area as runoff.

2) steep land: if there is steep land then the runoff reaches the river very quickly causing increase in discharge.

3) impermeable rock: if there is impermeable rock then all of the water will reach the ground as runoff.

4) many tributaries: if there are many tributaries then the main river receives a lot of discharge all at once. the main river then quickly reaches bank full discharge.

5) deforestation: if there is deforestation then there is no interception so water becomes runoff.

6) urbanisation: if there is urbanisation there will be no infiltration and no interception.

Question 20

what is attrition

Answer 20

• erosional process
• rocks and pebbles and carried in the river flow and repeatedly collide with each other, this causes them to erode and eventually become sediment

Question 21

what is corrasion

Answer 21

mechanical/ physical erosion of the earths surface caused when materials are transported by waves, wind water etc

Question 22

what is corrosion

Answer 22

• chemical erosion
• when water or acid rain enters a rocks through cracks and through chemical reactions it caused erosion.

Question 23

what is hydraulic action

Answer 23

when the force of water crashes against the coastline and dislodges materials, carrying them away

Question 24

what is traction

Answer 24

method of transporting rocks / large stones. The stones are rolled along the river bottom by water.

Question 25

what is saltation

Answer 25

rocks and pebbles that are to big to carry bounce along the bottom of the river

Question 26

what is suspension

Answer 26

sediment that is properly erode from larger rocks up stream are then carried by the water. when deposited its know as slit.

Question 27

what is solution

Answer 27

when water dissolves certain types of rocks eg limestone

Question 28

what is the equation for limestone and acid rain

Answer 28

CaCO3+2H2OCO3—->Ca(HCO3)2+H2O+CO2

limestone + acid rain —> bicarbonate + water +carbon dioxide

Question 29

what is weathering

Answer 29

the breakdown of material by chemical, physical or biological means