rivers

Question 1

precipitation

Answer 1

Moisture falling from clouds as rain, snow, or hail.

Question 2

Interception

Answer 2

Vegetation prevents water from reaching the ground

Question 3

Surface Runoff

Answer 3

Water flowing over the surface of the land into rivers

Question 4

Infiltration

Answer 4

Water absorbed into the soil from the ground.

Question 5

Transpiration

Answer 5

Water lost through the leaves of plants.

Question 6

Upper Course of a River

Answer 6

Near the source, the river flows over a steep gradient from the hill/mountains. This gives the river a lot of energy, so it will erode the riverbed vertically to form narrow valleys

Question 7

Lower Course of a River

Answer 7

Near the river’s mouth, the river widens further and

becomes flatter. Material transported is deposited

Question 8

physical causes of flooding

Answer 8

Long periods of rain causes soil to become saturated leading to runoff.

Steep-sided valleys channel water to flow quickly into rivers causing greater discharge.

Impermeable rocks cause surface runoff to increase river discharge.

Question 9

human causes of flooding

Answer 9

Tarmac and concrete are impermeable. This prevents

infiltration & causes surface runoff.

Question 10

Formation of a Waterfall

Answer 10

1) River flows over alternative types of rocks.
2) River erodes soft rock faster creating a step.

3) Further hydraulic action and abrasion form a plunge
pool beneath.

4) Hard rock above is undercut leaving cap rock which
collapses providing more material for erosion.

5) Waterfall retreats leaving steep-sided gorge.

Question 11

Formation of Floodplains and levees

Answer 11

The river channels get shallower during low flow conditions, causing deposition on the river bed.
This means that the river cannot hold as much water as before as the river bed has risen.
During a flood, sediment is deposited on the river banks; depositing coarser (heavier) sediment nearer to the river and finer sediment further away.

Question 12

River Discharge

Answer 12

River discharge is the volume of water that flows in a river.

Hydrographs that discharge at a certain point in a river changes over time in relation to rainfall

Question 13

Peak discharge

Answer 13

the discharge in a period of time

Question 14

. Lag time

Answer 14

the delay between peak rainfall and peak discharge

Question 15

. Rising limb

Answer 15

the increase in river discharge.

Question 16

Falling limb

Answer 16

the decrease in river discharge to normal level

Question 17

Factors affecting hydrographs

Answer 17

Basin size – small flashy *Drainage density - high = flashy

rock type - impermeable = flashy *Land Use urbanisation = flashy *Relief - steep = flashy

Soil moisture – saturated = flashy * Rainfall Intensity –
high = flashy .

opposite characteristics & precipitation = SUBDUED

Question 18

The River Tees location and background

Answer 18

Located in the North of England and flows 137km from the Pennines to the North Sea at Red Car.

Question 19

Geomorphic Processes Upper

Answer 19

– Features include V-Shaped valleys, rapids, and waterfalls.
High force Waterfall located close to Forest-in Teesdale drops 21m

and is made from harder Whinstone and softer limestone rocks.

Gradually a gorge has been formed.

Question 20

geomorphic processes middle

Answer 20

– Features include meanders and ox-bow lakes. The

meander near Yarm encloses the town.

Question 21

geomorphic processes lower

Answer 21

– Greater lateral erosion creates features such as floodplains & levees near Darlington. Mudflats at the river’s estuary.

Question 22

Middle Course of a River

Answer 22

Here the gradient gets gentler, so the water has less energy and moves more slowly.

The river will begin to erode laterally making the river wider.

Question 23

Soft Engineering

Answer 23

Soft engineering involves adapting to natural hazards and working with nature to limit the damage. For example, planting trees to limit flood risk.

Question 24

Hard Engineering

Answer 24

Building structures to deal with natural hazards, such as dams to prevent flooding

Question 25

Formation of Ox-bow Lakes Steps

Answer 25

Erosion of outer bank forms river cliff. Deposition inner bank forms slip-off slope.
Further hydraulic action and abrasion of outer banks, the neck gets smaller
Erosion breaks through the neck, so the river takes the fastest route, redirecting the flow
Evaporation and deposition cuts off main channel leaving an oxbow lake

Question 26

Flood Relief Channel Social Issues:

Answer 26

Protection of wealthy properties in Maidenhead and Eton at the expense of less affluent areas further downstream at Wraysbury.

Question 27

Flood Relief Channel Economic Issues:

Answer 27

It was the most expensive flood relief scheme
in the UK.

Floods in 2003 damaged weirs – the cost of maintenance is quite high.

Additional local relief measures are required
downstream; the scheme has not so much solved the
problem but shifted it elsewhere – serious flooding in
2014

Question 28

Flood Relief Channe Environmental Issues:

Answer 28

Environmental Issues:
Extensive flooding in 2014 below the confluence of the
River Thames and the flood relief channel damaged
habitats. Concrete weirs are unattractive.

Question 29

What are ‘interlocking spurs’?

Answer 29

‘Interlocking’ hillsides that look like a ‘zip’ formation.

Question 30

How are interlocking spurs formed?

Answer 30

In the upper course, rivers aren’t powerful enough to erode laterally, so they wind around the hillsides creating a zig-zag shaped flow.

Question 31

What are the characteristics of the upper course of a river?

Answer 31

Steep gradient
Narrow v-shaped valley
Narrow/shallow river
Large angular sedimant load
Mostly erosion taking place

Question 32

What are the characteristics of the middle course of a river?

Answer 32

Shallower gradient
Asymmetrical valley cross section
Deeper river
Smaller/rounded load
Balance between erosion and transportation taking place

Question 33

What are the characteristics of the lower course of a river?

Answer 33

Very low gradient
U-shaped valley
Wide/deep river
Small suspended load
Mostly deposition taking place

Question 34

• when does deposition happen

Answer 34

when a rivers velocity decreases, and it no longer has the energy to transport its load, it deposits it.

Question 35

• describe deposition

Answer 35

larger rocks transported mainly by traction are only carried short distances during periods of high flow. they are deposited in a rivers upper coarse.

smaller sediment is carried further downstream- mostly in suspension. it is depostied on a rivers bed and banks where velocity slows down due to friction 

lots of deposition occurs at a rivers mouth where its velocity reduces because of the gentle gradienct and also by interaction with tides

Question 36

• formation of Gorges

Answer 36

a gorge is narrower, steep sided valley found downstream of a retreating waterfall.

gorges can form in other ways- at tje end off the last glacial period masses of water from melting glaciers poured off upland areas  forming gourges 

on lime stone, when large underground caverns can accomodate an entire river.

Question 37

— describe an estuarie

Answer 37

n estuary is where the river meets the sea. they are affected by tides, wave action and river processes. as the tides rise the rivers can flow into the sea, so velocity falls and sediment is deposited forming mudflats, which develop into salt marshes

Question 38

• what causes flooding

Answer 38

river floods usually occur after long periods of rain- most frequently during winter

sudden floods, called flash floods, tend to occur in summer and associated with heavy rainstorms 

]physical and human factrs can increase flood risk

Question 39

• define and describe the human factors of flooding

Answer 39

Urbanisation- impermeable surfaces mean water flows quickly into drains, sewers and river channels

deforrestation- when trees are removed, much of the water which had been evaporated from leaves or stored on leaves and branches flows rapidly into river channels 

agriculture- exposed soil can lead to increased surface runoff