Rivers

Question 1

what is the river like in the upper course?

Answer 1

steep
v-shaped
steep sides
narrow
shallow channel

Question 2

what is the river like in the middle course?

Answer 2

medium gradient
gently sloping sides
wider
depper channel

Question 3

what is the river like in the lower course?

Answer 3

low gradient
very wide
almost flat
very wide
deep channel

Question 4

what are the 5 processes of erosion in a river?

Answer 4

• vertical and lateral erosion
• hydraulic action
• abrasion
• attrition
• solution

Question 5

what does vertical erosion do the river?

Answer 5

• deepens river channel, V-shaped

- upper course

Question 6

what does lateral erosion do to the river?

Answer 6

• widens Vally

- middle and lower course

Question 7

what is hydraulic action?

Answer 7

force of water breaks down rocks away from river channel

Question 8

what is abrasion?

Answer 8

• eroded rock scrape channel

- most erosion is abrasion

Question 9

what is attrition?

Answer 9

• eroded rock smash into each other

- edges round off

Question 10

what is solution?

Answer 10

-river water dissolves certain types of rock i.e. limestone

Question 11

what is transportation?

Answer 11

movement of eroded material

Question 12

what are the 4 main methods of transportation?

Answer 12

• traction
• saltation
• suspension
• solution

Question 13

what is traction?

Answer 13

large particles push along river bed by water

Question 14

what is saltation?

Answer 14

pebble sized bounce along river bed by water

Question 15

what is suspension?

Answer 15

small particles like soil and clay carried in water

Question 16

what is solution?

Answer 16

soluble material dissolved in water carried along

Question 17

what are the 4 reasons a river deposits material?

Answer 17

• volume of water in river falls
• eroded material increases
• sallow water
• river reaches mouth

Question 18

what are the 3 land formed formed from erosion?

Answer 18

• waterfalls and gorges

- interlocking spurs

Question 19

how are waterfalls and gorges formed?

Answer 19

• river flows over hard rock which is over soft rock
• soft rock eroded by hydraulic action and abrasion
• step formed
• water flows over step erodes more soft rock
• steep drop formed, WATERFALL
• hard rock undercut, collapse
• rock erodes at base by abrasion
• more undercutting, collapse
• waterfall retreats, GORGE

Question 20

how are interlocking spurs formed?

Answer 20

• upper course river erode vertically
• v-shaped valleys
• not powerful enough to erode laterally
• wind around high hillsides
• leaving interlocking spurs

Question 21

what are the landforms formed form erosion and deposition?

Answer 21

meanders and ox-bow lakes

Question 22

how are meanders formed?

Answer 22

• current faster on outside bend
• more erosion on outside, forming river cliffs
• current slower as its shallower on inside
• so eroded lateral deposited
• this formed slip off slopes

Question 23

how are ox-bow lakes formed?

Answer 23

• erosion in a meander, outside bend closer
• small neck
• breaks through, flood
• river goes shortest course
• deposition cuts off meander
• ox-bow lake left

Question 24

how are the landforms formed from deposition?

Answer 24

• levées
• flood plains
• estuaries

Question 25

how are flood plains formed?

Answer 25

- wide valley floor - prone to flooding - flooded deposition occurs on floodplain - builds up floodplain - meanders get wider making it bigger

Question 26

how are levées formed?

Answer 26

- natural embankment - flood, eroded material deposits on floodplain - heaviest closest to river - over time creates levées

Question 27

how are estuaries formed?

Answer 27

- where river meets sea - mouth of river - tidal (rises and falls each day) - tide at high point, water moves slowly so deposition - creates mudflats - low tide, mudflats exposed

Question 28

what are some of the major erosion and deposition landforms on the River Tees?

Answer 28

- High Force waterfall - meanders at Dent Bank - tight meander and floodplain at The Holmes

Question 29

what are the 4 main physical factors which cause a river to flood?

Answer 29

- prolonged rainfall - heavy rainfall - geology (rock type) - relief (change in height)

Question 30

how does prolonged rainfall make a river flood?

Answer 30

- soil saturated - rain can't infiltrate - high runoff - flooding

Question 31

how does heavy rainfall make a river flood?

Answer 31

- cant infiltrate, too quick - high runoff - discharge quickly - flood

Question 32

how does geology make a river flood?

Answer 32

- clay soils, granite - impermeable, no infiltration - high runoff - discharge increases quickly - flood

Question 33

how does relief make a river flood?

Answer 33

- steep sided valley - reach river quickly - flows quickly - discharge increases - flood

Question 34

what human factor makes a river flood?

Answer 34

land use

Question 35

how does land use make a river flood?

Answer 35

- buildings are made of impermeable materials - drives, tarmac - trees intercept water, cutting down trees stops the interception - disappearing gardens

Question 36

what do hydrography show?

Answer 36

discharge at certain point changes over time in relation to rainfall

Question 37

what is river discharge?

Answer 37

- volume of water flowing into river per sec. | - cumecs

Question 38

what is peak discharge?

Answer 38

highest discharge

Question 39

what is lag time?

Answer 39

delay between peak rainfall and peak discharge

Question 40

what is rising limb?

Answer 40

increase in river discharge as rainwater flows into river

Question 41

what is falling limb?

Answer 41

decrease in river discharge as river returns to normal level

Question 42

why does lag time happen?

Answer 42

most water doesn't land directly in the river

Question 43

what are the 4 main hard engineering strategies?

Answer 43

- dams and reservoirs - channel straightening - embankments - flood relief channels

Question 44

what are the advantages and disadvantages of dams and reservoirs?

Answer 44

A- store lots of water A- drinking water A- hydroelectric power D- expensive

Question 45

what are the advantages and disadvantages of channel straightening?

Answer 45

A- moves out of area quickly D- flooding downstream D- erosion downstream, fast moving water

Question 46

what are the 5 main soft engineering strategies?

Answer 46

- flood warnings - preparation - flood plain zoning - planting trees - river restoration

Question 47

what is an example of a flood management scheme in the UK?

Answer 47

Jubilee river flood reel channel

Question 48

why was the scheme required(Jubilee river)?

Answer 48

- low lying - prone to flooding - royal settlement (Windsor) attracts visitors - Eton school

Question 49

what measures were taken(Jubilee river)?

Answer 49

Jubilee river was created to take overflow water from the Thames during high discharge

Question 50

what were the social issues(Jubilee river)?

Answer 50

-is it ethical to protect wealthier places over others

Question 51

what were the economical issues(Jubilee river)?

Answer 51

- most expensive in the UK - but damaged a year later by floods - £330million - until solution found small business couldn't operate while flooded

Question 52

what were the environmental issues(Jubilee river)?

Answer 52

- concrete weirs are ugly | - algae collecting behind weirs disrupting other habitats