Rivers Key Terms

Question 1

Long profile

Answer 1

The rivers course from source to mouth.

Question 2

Cross profile

Answer 2

The river from bank to bank at any given point

Question 3

Upper course

Answer 3

Part of the river nearest the source characterised by V shaped, steep valleys

Question 4

Middle course

Answer 4

Central part of a river where the valley widens and slope are gentler

Question 5

Lower course

Answer 5

Last stage of a river before it reaches the sea, wide very flat valley floor.

Question 6

Vertical erosion

Answer 6

Erosion that works downwards into the land creating a V-Shaped valley

Question 7

Lateral erosion

Answer 7

Erosion that works sideways to widen the river channel.

Question 8

Hydraulic action

Answer 8

The force of water hitting the bed and banks breaking it up.

Question 9

Abrasion

Answer 9

The load carried by the river repeatedly hits the bed and banks dislodging particles into the flow of the river

Question 10

Attrition

Answer 10

Stones carried by a river knock and bang into each other gradually making the stones smaller and more rounded

Question 11

Solution (erosion)

Answer 11

When the rock is slowly dissolved in mildly acidic river water

Question 12

Traction

Answer 12

When large particles are rolled along the river bed.

Question 13

Saltation

Answer 13

When particles carried by the river are bounced along as they are too heavy to be carried in suspension.

Question 14

Suspension

Answer 14

small sediments that are held within the river’s water

Question 15

Solution (transportation)

Answer 15

the river carries the dissolved load.

Question 16

Deposition

Answer 16

sediment is dropped by the river when the energy is reduced towards the mouth.

Question 17

Waterfall

Answer 17

a step in the long profile of river over which water falls, usually when the river passes over a band of resistant rock.

Question 18

Gorge

Answer 18

a vertically sided gash in the land formed when a wtaerfall retreats upstream

Question 19

Interlocking spur

Answer 19

created as a river winds its way through the upper course.

Question 20

Meander

Answer 20

a wide bend or curve in the river found mainly in the middle and lower sections of a river.

Question 21

River cliff

Answer 21

cliff like feature created on the outside of a meander where flow is quickest and erosion at its greatest.

Question 22

Slip off slope

Answer 22

a river beach created on the inside of a meander where flow is slower and deposition takes place

Question 23

Ox-bow lake

Answer 23

curved lake created when the neck of a meander is cut off through constant erosion.

Question 24

Flood plain

Answer 24

the wide flat area of land side of a river in the middle and lower course of a river

Question 25

Levee (natural)

Answer 25

raised banks alongside the river created over years of flooding and deposition of sediment

Question 26

Estuary

Answer 26

An estuary is the transitional zone between the river and coastal areas, they are affected by wave action and river processes

Question 27

Hydrograph

Answer 27

A graph which plots river discahrge after a storm and includes the volume of rain that falls.

Question 28

Rising limb

Answer 28

The part of the hydrograph which shows the increase in discharge

Question 29

Falling limb

Answer 29

The part of the graph which shows the discharge of a river returning to normal

Question 30

Peak discharge

Answer 30

When the amount of water in the river is at its highest

Question 31

Lag time

Answer 31

The number of hours between the peak rainfall and the peak discharge

Question 32

Infiltration

Answer 32

Water passes through the surface into the soil and underlying rock.

Question 33

Surface runoff

Answer 33

Water flows over the surface into the river.

Question 34

Interception

Answer 34

Waters route to the ground is slowed by trees and vegetation

Question 35

Impermeable rock

Answer 35

Rock which does not allow water to pass through it.

Question 36

Permeable rock

Answer 36

Rock which is porous and allows water to pass through it.

Question 37

Relief of the land

Answer 37

The shape of the land, whether its is flat or hilly.

Question 38

Hard engineering

Answer 38

Involves the use of man made structures to prevent or control natural processes taking place. E.g. dams and reservoirs

Question 39

Soft engineering

Answer 39

Involves working with the natural river processes to manage flood risk e.g floodplain zoning

Question 40

Dam/reservoir

Answer 40

When a rivers flow is blocked by a man made barrier, the flooded land behind the dam becomes a reservoir

Question 41

Channel straightening

Answer 41

When the natural course of the river is straightened to increase the flow rate.

Question 42

Embankments

Answer 42

Artificial banks built up on either side of the river to icrease the capacity of the river

Question 43

Flood relief channel

Answer 43

Channels are built to take water away from the main river during times of flood to relieve the pressure on the main channel

Question 44

Flood plain zoning

Answer 44

Restrictions placed on the developments allowed on the floodplain to reduce the damage caused when rivers flood

Question 45

River restoration

Answer 45

Returning rivers that have been artificially altered to their natural course