Rivers

Question 1

What are the feature of the river?

Answer 1

Watershed     Source
Tributaries     Confluence 
Estuary          Delta
Mouth            Course 
Basin             Distributaries

Question 2

What is a water shed

Answer 2

The line dividing the waters of a river and its tributaries (river basin) from those of another river and its tributaries (another river basin)

Question 3

What are tributaries

Answer 3

Smaller rivers that join a larger river

Question 4

What is a confluence

Answer 4

The place where tributaries join the main river

Question 5

What is an estuary

Answer 5

The tidal mouth of a river

Question 6

What is delta

Answer 6

Land that forms at the mouth of rivers

Question 7

What is the mouth of a river

Answer 7

Where the river enters the sea or lake

Question 8

What is a source

Answer 8

Where the river begins

Question 9

What is a course

Answer 9

The path of the river from the source to mouth

Question 10

What is a basin

Answer 10

The area drained by the river and its tributaries

Question 11

What are distributaries

Answer 11

Small rivers that break of from the main reason I we as it enters the sea

Question 12

What is erosion

Answer 12

The wearing away of rock, the transport of that rock and its deposition. This is carried out by rivers, moving ice and the sea

Material transported by a river is called its load

Question 13

What is hydraulic action

Answer 13

This is the erosion carried out by the force of the flowing water in the river

Question 14

What is abrasion

Answer 14

When the river uses it’s load to erode the bed and banks (channel of the river)

Question 15

What is attrition

Answer 15

The rivers load is worn down when the pieces collide so that the stones are smoothened and made smaller

Question 16

What is solution (erosion)

Answer 16

Some rocks, such as limestone, are dissolved in the river.

Question 17

What is solution (transport)

Answer 17

Rock minerals are dissolved in the water and carried away

Question 18

What is saltation

Answer 18

Small stones are bounced along the bed of the river

Question 19

What is suspension

Answer 19

Light material, such as silt, is transported in the water

Question 20

What is traction

Answer 20

Larger rocks are rolled along the river bed

Question 21

What is deposition

Answer 21

When a river slows down, it loses energy, so it deposits some of its material or load

This happens when a r ver enters a lake, or on the inner bend of a meander

Question 22

What is the youthful stage of a river

Answer 22

Erosion ; most active during this stage (upper course). River rushes along and wears away the bed of the river, this is called vertical erosion .

Forming - V shaped valleys, steep sides and narrow valley floor, Gravity causes regolith on the valley sides to move downslope
Waterfalls

Question 23

How are waterfalls formed

Answer 23

1) a band of hard rock lies next to softer rock
2) the river erodes the softer rock faster than the hard rock, creating the water fall
3) a plunge Poole develops at the base of a waterfall, caused by hydraulic action and abrasion, the river undercuts the harder rock, creating an overhang
4) the rock overhead collapses
5) the water fall retreats upstream
E.g. Powerscourt waterfalls

Question 24

What is the mature stage of a river

Answer 24

Valleys in the mature stage are wider, with gentler valley sides. The river erodes laterally (on the sides or banks), widening the valley, and vertically (on the bed of a river), deepening the river channel

Forming - floodplain, a flat area along the river course that is flooded by the river. As the river floods, it lays down alluvium on the valley floor
Alluvium - a mixture of clay, silt, sand, gravel and other materials

Question 25

How are meanders formed

Answer 25

1) water flows faster on the outer bend. The river erodes the bank of the river here by undercutting the bank and causing it to collapse (erosion)
2) the water flows slower on the inner bend. The river deposits some of its load here

This makes the inner bend more prominent

Question 26

What is the old-age stage of a river

Answer 26

In the old age stage, the river slows down and meanders. It deposits its loaf either because it is losing energy or because the load is too great
Forming - Ox - bow lakes, when a river cuts through a bend in the meander leaving a C like shape of a lake separate to the river as the river deposits it load there blocking it of. levees

Question 27

What are the causes of flooding

Answer 27

Usually occurs during the winter months and is often caused by extreme weather conditions, such as a number of days of heavy rainfall. But the way people manage rivers can also contribute to the flooding

E.g poorly constructed bridges, weirs and failure to dredge the riverbed can all force the extra water out onto the land

Question 28

Effects of flooding include….

Answer 28

Deaths
Ruined farmland
Food prices increase
Higher tax

Question 29

What is a dam

Answer 29

A dam is a barrier to hold back the flow of a river. The main dams in Roland were built to produce electricity. They also act as reservoirs to store water