River Landscapes

Question 1

what is a drainage basin?

Answer 1

an area which is drained by a river and its tributaries

Question 2

what is the source?

Answer 2

an area where a river begins

Question 3

what is the mouth?

Answer 3

where’s river ends its journey - flowing into the sea or a lake

Question 4

what is a tributary?

Answer 4

a small river that joins a larger river

Question 5

what is a confluence?

Answer 5

the point where two rivers join

Question 6

what is watershed?

Answer 6

the boundary between two drainage basins marked by a ridge of highland

Question 7

what are the three types of course a river goes through?

Answer 7

upper, middle and lower

Question 8

what are features of the upper course?

Answer 8

valley: steep gradient, V-shaped
river: narrow, shallow, turbulent

Question 9

what are features of the middle course?

Answer 9

valley: wider, flat floor
river: wider and deeper channel

Question 10

what are features of the lower course?

Answer 10

valley: very wide and flat
river: wide and deep

Question 11

what is vertical erosion?

Answer 11

•deepens the valley, making it V-shaped
•dominant in the upper couse
•high turbulence causing rough, angular particles to be scraped along the river bed
•causes intense downward erosion

Question 12

what is lateral erosion?

Answer 12

•widens the river valley during formation of meanders
•dominant in the middle and lower course

Question 13

what is hydraulic action?

Answer 13

force of water breaks rock particles away from the cliff face

Question 14

what is abrasion?

Answer 14

eroded rocks picked up by river scraps and run again the channel, wearing it away

Question 15

what is attrition?

Answer 15

eroded rocks picked up by others, smashed into eachother, break into smaller fragments, edges rounded off

Question 16

what is corrosion/solution?

Answer 16

river water dissolves some types of rock (chalk and limestone)

Question 17

what are reasons why rivers slow down and deposit material?

Answer 17

•volume of water falls
•eroded material increases
•shallow water
•river reaches its mouth

Question 18

what is the definition of a waterfall?

Answer 18

the drop of a stream over a very steep slope

Question 19

what is a waterfall made by and what part of the river course is it found in?

Answer 19

•erosion
•upper and middle river

Question 20

what is the process of how a waterfall is formed?

Answer 20

1) soft rock is worn away
2) hard rock is undercut and unsupported
3) hard rock collapses
4) waterfall retreats upstream
5) steep-sided gorge is left behind

Question 21

what is the definition of a V-shaped valley and interlocking spurs?

Answer 21

V-shaped Valley: steep river valleys found in the upper section. formed by vertical erosion
Interlocking Spurs: ridges of land that cut across the path of a stream, forcing the stream to wind around it

Question 22

what is a V-shaped valley and an interlocking spur made by and where are they found in a rivers course?

Answer 22

•erosion
•upper river

Question 23

what is the process of how interlocking spurs and V-shaped Valleys are formed?

Answer 23

1) rocks and pebbles are moved along the river bed
2) river erodes vertically
3) sloped attacked by heavy rain
4) valley sides slowly move downhill
5) V-shaped valley is formed
6) aren’t strong enough to erode laterally, have to wind around high hillsides
7) hillsides interlock (are called interlocking spurs)

Question 24

what are the definitions of meanders and ox-bow lakes?

Answer 24

•meanders: a river approaching its mouth that flows over flatter land and develops into large bends
•ox-bow lakes: neck of a meander, becomes narrower, river eventually cuts through the neck shortening its course. deposition block the old bend, leaving an ox-bow lakes

Question 25

what landforms are meanders and ox-bow lakes made by and where are they found in a rivers course?

Answer 25

•erosion and deposition •middle and lower river

Question 26

what is the process of how meanders and ox-bow lakes are formed?

Answer 26

•meanders: 1) faster current on the outside of the bend so more erosion takes place 2) banks are undercut and worn away, river channel is deepened 3) slower current on the inside of the bend so eroded material is deposited forming slip-off slopes 4) shallows the channel •ox-bow lakes: 1) outside of the bend is worn away by erosion 2) neck gets narrower 3) river cuts through the neck and deposition builds up 4) meander is cut off from the main river and an ox-bow lake is formed

Question 27

what are the definitions of floodplains and levees?

Answer 27

•floodplains: area of flatland either side of a river which is submerged during a flood •levees: natural embankments either side of a river make of sand and gravel

Question 28

what are floodplains and levees made by and where are they found in a rivers course?

Answer 28

•floodplains: erosion, deposition •levees: deposition •both: middle and lower river

Question 29

what is the process of how floodplains and levees are formed?

Answer 29

•floodplains: 1) water deposits eroded material building up the floodplain 2) meanders migrate making them wider and flatter •levees: 1) eroded material is deposited 2) heaviest material deposits closest to the chanel (dropped first) 3) builds up overtime forming levees

Question 30

what is the definition of an estuary?

Answer 30

where freshwater from rivers and streams meets and mixes with saltwater from the ocean

Question 31

what landform are estuary’s made by and where are they found in a rivers course?

Answer 31

•deposition •lower course

Question 32

what is the process of how estuaries are formed?

Answer 32

1) water floods over the banks carrying silt and sand 2) tide reaches its highest point so water is moving slowly and sediment is deposited 3) large mudflats are created over time 4) at low tide, the wide, muddy banks are exposed

Question 33

what factors can cause rivers to flood?

Answer 33

•prolonged and heavy rainfall (cannot absorb, so lots of surface runoff) •geology (rock type - some are impermeable so don’t allow water, so runoff is increased •relief (change in height of land - steep means faster surface runoff) •landuse (buildings made from impermeable materials, increasing runoff and trees intercept with rainwater, taking it up, so cutting them down increases risk of flooding)

Question 34

what is the definition of deltas?

Answer 34

fan-shaped areas at the mouth or lower end of a river, formed by eroded material that has been carried down steam and dropped

Question 35

where are deltas found and what are they made by?

Answer 35

•lower river •depostion

Question 36

what is the process of how deltas are formed?

Answer 36

1) river carries large amounts of material 2) river slows as it reaches the sea and deposits material 3) land builds up 4) river divides into a number of streams (distributaries)

Question 37

what are the features of dams and reservoirs?

Answer 37

•huge walls with water built up behind them. stores water so can be released during rainfall to keep it constant •provides flood prevention, hydro-electric power, irrigation, recreation, water supply and entertainment •very expensive, farmland can be less fertile, floods large areas of land

Question 38

what are the features of channel straightening?

Answer 38

•meanders are cut out to straighten a rivers course •water moves quicker reducing flooding, protects vulnerable locations •increased flood risk further downstream, unattractive, can damage habitats

Question 39

what are the features of embankments?

Answer 39

•raised walls along a river back, allowing more water in •can hold more water, mud dredged from the river may be used which is cheaper and sustainable •difficult to get to river banks, expensive, affect habitats

Question 40

what are the features of flood relief channels?

Answer 40

•diverts water around when it gets too high in one area •reduces threat of flooding, gates mean release of water can be controlled •relief channels could flood if it gets too high

Question 41

what are features of floodplain zoning?

Answer 41

•restricts different land used away from floodplains •risk of flooding is reduced, kept clear of high value land, reduces losses by flood damage

Question 42

what are the features of river restoration?

Answer 42

•natural processes and features of a river •little maintenance, uses meanders and wetlands, slows river flow, better habitats for wildlife •local flood risk can increase

Question 43

what are features of preparing for floods?

Answer 43

•monitored using satellites and computer technology, modified buildings, people are made to plan ahead •flooding impact is reduced, buildings are less damaged, people know what to do and are less likely to worry •doesn’t guarantee safety, false sense of security, expensive to modify buildings, property values drops, insurance increases

Question 44

what are these features about the Boscastle Flood? •date •location

Answer 44

•16 August 2004 •South West of England, County of Cornwall, along the North Coast of Cornwall

Question 45

how did the Boscastle Flood occur?

Answer 45

•extreme rainfall caused by huge cumulonimbus clouds at 40,000ft •steep valleys •River Jordan and River Valency confluence (two rivers meet) •thin soil, impermeable rock •200mm of rainfall in 24 hours •deforestation reduced interception •tourist car park increased surface runoff

Question 46

what are some effects of the Boscastle Flood?

Answer 46

S - homes destroyed, harbour destroyed, cars washed into the sea, decrease in tourism Ec - decrease in tourism, tourist shops destroyed, costed £15 million, increasing insurance prices that people aren’t willing to pay En - cars washed into the sea causing pollution, contaminated water, river bank erosion, roads ripped apart

Question 47

what are some responses to the Boscastle Flood?

Answer 47

•police and ambulance •rescue helicopters •diving teams underwater •blocked shop doors •no dead due to immediate responses

Question 48

what hard engineering strategies were used for the Boscastle Flood?

Answer 48

•concrete tunnel (takes water out main channel into rivers, helping it diverge, preventing flooding in main areas) •new drainage systems (water runs to lower sections) •river channel straightened, widened and deepened (more water can accommodate efficiently) •new bridge built (widens channel) •car park moved away and raised (stops river bursting its banks so easily due to height, tarmac changes to permeable, cost £500,000) •sewage scheme (£1.5 million on 2 pumping systems to pump away excess rain)

Question 49

what soft engineering strategies were used for the Boscastle Flood?

Answer 49

•tree management (got rid of ones that may be causing problems, like a dam) •early warning systems (make people aware)