Rivers

Question 0

What is a tributary?

Answer 0

A stream or river that flows into another river

Question 1

What is a confluence?

Answer 1

The junction of two Rivers

Question 2

What is the mouth?

Answer 2

Where a river ends

Question 3

What is a river channel?

Answer 3

What a river flows in

Question 4

How do tributaries affect a river’s discharge?

Answer 4

A rivers discharge will increase as tributaries join it

Question 5

What is the River basin?

Answer 5

The area of land drained by a river

Question 6

What is the watershed?

Answer 6

The edge of River basin

Question 7

What is the source?

Answer 7

Where a river starts

Question 8

What is interception?

Answer 8

Precipitation may not reach the ground surface if it is caught on leaves
It may then be directly evaporated

Question 9

How does deforestation affect a river’s discharge?

Answer 9

If the area is deforested then the amount of surface runoff increases
More discharge

Question 10

What does rainfall do to discharge?

Answer 10

Heavy continuous rainfall will increase a rivers discharge

Question 11

What is the water table?

Answer 11

Upper limit of saturated rock or soil
It moves up or down according to rainfall conditions
Drought is down

Question 12

What is a waterfall?

Answer 12

A steep drop in the course of a river

Question 13

Why do waterfalls form?

Answer 13

Form when a band of hard rock lies over soft rock

Question 14

Where along the river do waterfalls form?

Answer 14

In the upper course of a river

Water is fast-moving

Question 15

How are meanders formed?

Answer 15

As river erode laterally, to right and then left side, it forms large bends called meanders
Water or roads and undercuts bank on outside of band– most energy here due to decreased friction
Material is deposited on inside of Bend – less energy here due to increased friction

Question 16

When do oxbow lakes normally form?

Answer 16

During a flood when the river is particularly powerful

As floodwaters fall, alluvium is deposited sealing the river

Question 17

What happens to the Oxbow lake?

Answer 17

Gradually the oxbow lake dries up forming a meander scar

Question 18

What do flood hydrographs show?

Answer 18

The discharge of a river (m/s3) - line
The rainfall (mm) - bar graph

Question 19

What is lag time?

Answer 19

Time between the peak rainfall and peak discharge

Question 20

What is a flood?

Answer 20

A flood occurs when a river burst its banks and water spills onto the floodplain

Question 21

Why does flooding occur?

Answer 21

Tends to be caused by heavy rain
Steep sided channel – cause fast surface runoff
Lack of vegetation or Woodland – no transpiration means high surface runoff
In permeable drainage basin – water cannot percolate through rock, faster surface runoff
Urban area – concrete means impermeable, it drains take water to river channel, sloped roofs

Question 22

How do you prevent a flood?

Answer 22

River engineering
Afforestation
Restriction of urban development on floodplains

Question 23

What happens on the first stage of river?

Answer 23

Useful, upper, torrent
V-shaped valley
Steep Valley sides
Mainly a vertical erosion where river cuts downwards
Waterfalls, rapids, fast flowing water, whirlpools
Water rafting, Hydro electric, reservoir, hotels

Question 24

What happens on the second river stage?

Answer 24

Maturer, middle, Valley
U-shaped Valley
Gently sloping sides
Erosion on bend side – lateral erosion
Deposition – slip off slopes
Transportation of material
Meanders, Rivercliff, slip off slopes, oxbow lakes
Fishfarming, mixed woodland, railway lines

Question 25

What happens on the third river stage?

Answer 25

Senile, lower, plain
Wide and deep
Deposition
During flood lots of erosion
Levees, oxbow lakes, meanders
Farming, railway lines on embankment, playing fields