1.4 River Landscapes and Processes (Paper 1) Flashcards Preview

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Flashcards in 1.4 River Landscapes and Processes (Paper 1) Deck (114)
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1
Q

<p>Define <strong>long profile</strong></p>

A

<p>The change in the<strong>gradient</strong>of the river course from the upper course to the lower course</p>

2
Q

<p>What is a '<strong>crossprofile</strong>'?</p>

A

<p>A cross section of the river - this shows a 'slice' of the river valley and channel</p>

3
Q

<p>What is a<strong>V-Shaped valley</strong>?</p>

A

<p>A valley with steep sides and a narrow bottom that has been formed by erosion</p>

4
Q

<p>What is a<strong>tributary</strong>?</p>

A

<p>A smaller river or stream flowing into a larger river</p>

5
Q

<p>What is a<strong>confluence</strong>?</p>

A

<p>The point where two rivers meet</p>

6
Q

<p>Define '<strong>load</strong>'</p>

A

<p>The amount of material carried by a river</p>

7
Q

<p>What is '<strong>sediment</strong>'?</p>

A

<p>Material such as sand and clay that is carried by a river</p>

8
Q

<p>What are the<strong>characteristics</strong>of the<strong>upper course</strong>of a river?</p>

A
<ul>
	<li>Steep gradient</li>
	<li>Narrow v-shaped valley</li>
	<li>Narrow/shallow river</li>
	<li>Large angular sediment load</li>
	<li>Mostly erosion taking place</li></ul>
9
Q

<p>What are the<strong>characteristics</strong>of the<strong>middlecourse</strong>of a river?</p>

A

<ul>
<li>Shallower gradient compared to upper course</li>
<li>Asymmetricalvalley cross section</li>
<li>Deeper river</li>
<li>Smaller/rounded load</li>
<li>Balance betweenerosion and transportation taking place</li></ul>

10
Q

<p>What are the<strong>characteristics</strong>of the<strong>lowercourse</strong>of a river?</p>

A
<ul>
	<li>Very low gradient</li>
	<li>U-shaped valley</li>
	<li>Wide/deep river</li>
	<li>Small suspendedload</li>
	<li>Mostly depositiontaking place</li>
</ul>
11
Q

<p>Define <strong>erosion</strong></p>

A

<p>The wearing away of rock by the natural processes of rivers, ice, wind and sea</p>

12
Q

<p>Name the<strong>4</strong>processes of river<strong>erosion</strong></p>

A
<ul>
	<li>Abrasion</li>
	<li>Attrition</li>
	<li>Hydraulic Action</li>
	<li>Solution</li>
</ul>
13
Q

<p>Define '<strong>hydraulic action</strong>'</p>

A

<p>Fast flowing water pushes air into cracks and the force of this causes the channel to break up over time</p>

14
Q

<p>Define '<strong>abrasion</strong>'</p>

A

<p>Sand and pebbles are dragged along the river bed, wearing it away</p>

15
Q

<p>Define '<strong>attrition</strong>'</p>

A

<p>Rocks and stones wear each other away as they knock together</p>

16
Q

<p>Define '<strong>solution</strong>' (erosion)</p>

A

<p>Rocks such as limestone are dissolved in acid rainwater</p>

17
Q

<p>Define '<strong>transportation</strong>'?</p>

A

<p>The movement of eroded material by natural processes such as wind, rivers and sea</p>

18
Q

<p>What are the<strong>4</strong>processes of <strong>transportation</strong></p>

A

<ol><li>Solution</li><li>Suspension</li><li>Saltation</li><li>Traction</li></ol>

19
Q

<p>Define '<strong>traction</strong>'</p>

A

<p>Big boulders and stones are rolled and dragged along the river bed</p>

20
Q

<p>Define '<strong>saltation</strong>'</p>

A

<p>Stones and pebbles bounce along the river bed</p>

21
Q

<p>Define '<strong>suspension</strong>'</p>

A

<p>Smallerparticles andstones (e.g. sand and silt) are carried along in the rivers flow</p>

22
Q

<p><strong>Define 'solution'</strong></p>

A

<p>Some material is dissolved into the river water and transported this way</p>

23
Q

<p>What does '<strong>deposition</strong>' mean?</p>

A

<p>When a river drops the sediment that it is carrying</p>

24
Q

<p>Why will a river<strong>deposit</strong>its load?</p>

A

<ul>
<li><strong>Drier weather</strong>(less water so less energy)</li>
<li><strong>River slows in speed</strong>(less speed so less energy e.g. inside bend of a river)</li>
<li><strong>River floods</strong>(water onto the flood plain and deposits layers fine silt and clay [this is known as alluvium] which is fertile and good for farming)</li>
</ul>

25
Q

<p>Name the river landforms formed by<strong>erosion</strong></p>

A
<ul>
	<li>Waterfalls</li>
	<li>Gorges</li>
	<li>Interlocking spurs</li>
</ul>
26
Q

<p>Name the river landforms formed by<strong>erosion</strong>and<strong>deposition</strong></p>

A

<ul>
<li>Meanders</li>
<li>Ox-bow Lakes</li>
</ul>

27
Q

<p>Name landforms created by<strong>deposition</strong> in rivers</p>

A

<ul>
<li>Floodplains</li>
<li>Levees</li>
</ul>

28
Q

<p>Name the landforms found in the<strong>upper course</strong>of a river valley</p>

A
<ul>
	<li>Waterfalls</li>
	<li>Gorges</li>
	<li>Interlocking Spurs</li>
	<li>Rapids</li>
</ul>
29
Q

<p>What is a<strong>waterfall</strong>?</p>

A

<p>A vertical fall of water where the course of a river is interrupted by a steep drop in the land it is flowing over</p>

30
Q

<p>How does a<strong>waterfall</strong>form?</p>

A

<ol><li>Water flows over harder rock followed by softer rock</li><li>The softer rock underneath the harder rock will erode over time (<em><strong>hydraulic action and abrasion</strong></em>) creating a step in the river</li><li>The hard rock is undercut by erosion</li><li>Eventually the hard rock will collapse as it is now unsupported creating a deep plunge pool</li><li>The process will continue over time creating a steep sided gorge</li></ol>

31
Q

<p>What is a<strong>gorge</strong>?</p>

A

<p>A steep-sided cut through the landscape formed over thousands of years by a retreating waterfall</p>

32
Q

<p>What is a<strong>plunge pool</strong>?</p>

A

<p>The area of deep water at the bottom of a waterfall, formed by hydraulic action and the grinding of rocks and pebbles</p>

33
Q

<p>What are '<strong>interlocking spurs</strong>'?</p>

A

<p>'Interlocking' hillsides that look like a 'zip' formation</p>

34
Q

<p>How are<strong>interlocking spurs</strong>formed?</p>

A

<p>In the upper course, rivers aren't powerful enough to erode laterally, so they wind around the hillsides creating a zig-zag shaped flow</p>

35
Q

<p>Name the landforms found in the<strong>middlecourse</strong>of the river</p>

A

<ul>
<li>Meanders</li>
<li>Ox-bow lakes</li>
</ul>

36
Q

<p>Define '<strong>helical flow</strong>'?</p>

A

<p>The corkscrew pattern offlow found in a river</p>

37
Q

<p>What is a<strong>meander</strong>?</p>

A

<p>A pronounced bend in a river</p>

38
Q

<p>What is an<strong>ox-bow lake</strong>?</p>

A

<p>A horse-shoe shaped lake shaped that is formed when a river bend is cut off from the main river and becomes isolated</p>

39
Q

<p>Explain how an<strong>ox-bow lake</strong>forms</p>

A

<ol><li>The river meanders across the valley and the river is eroding laterally (from side to side)</li><li>The river flows faster on the outside bends and erodes them</li><li>The river flows slowly on the inside bends and deposits material so its course is changing</li><li>Continual erosion and deposition narrows the neck of the meander</li><li>Often during a flood the river will cut through the neck</li><li>The river continues on its straighter path and the meander is abandoned</li><li>New deposition seals off the ends and the cut-off becomes an oxbow lake that will eventually dry up</li></ol>

40
Q

<p>Name the landforms found in the<strong>lower course</strong>of a river valley</p>

A

<ol><li>Wide floodplain</li><li>Levees</li><li>Deltas</li><li>Estuaries</li></ol>

41
Q

<p>What are<strong>mudflats</strong>?</p>

A

<p>Flat coastal areas formed when mud is deposited by rivers and coasts</p>

42
Q

<p>What is a<strong>levee</strong>?</p>

A

<p>Natural river embankments found along the river banks
They are formed when the river floods and material is deposited along the banks</p>

43
Q

<p>How is a<strong>levee</strong>formed?</p>

A

<p>During a flood, sediment is deposited on the river banks; depositing coarser (heavier) sediment nearer to the river and finer sediment further away</p>

44
Q

<p>Define '<strong>riverdischarge</strong>'</p>

A

<p>The amount of water flowing in a river at any one point</p>

<p>Volume × Velocity</p>

45
Q

<p>List the<strong>factors</strong>affecting<strong>river discharge</strong></p>

A
<ul>
	<li>Rock and soil type</li>
	<li>Land use</li>
	<li>Rainfall</li>
	<li>Weather conditions</li>
	<li>Relief</li>
</ul>
46
Q

<p>How can you recognise the<strong>upper course</strong>of a riveron an<strong>OS map</strong>?</p>

A

<ul>
<li>Contour lines are close together</li>
<li>River crosses lots of contour lines</li>
<li>Narrow river (thin blue line)</li>
<li>Spot heights are high numbers</li>
</ul>

47
Q

<p>How can you recognise the<strong>lower course</strong>of a river on an<strong>OS map</strong>?</p>

A
<ul>
	<li>Limited contours or very wide contours (land is flat)</li>
	<li>Wide river that is meandering</li>
	<li>Spot heights are low numbers</li>
</ul>
48
Q

<p>Name an example of a river valley in the UK</p>

A

<p>River Tees</p>

49
Q

<p>How can you recognise a<strong>V-shapedvalley</strong> on an<strong>OS map</strong>?</p>

A

<p>V-shaped contours point uphill and river crosses the middle of the V-shaped contours</p>

50
Q

<p>Where is the River Tees?</p>

A

<p>In the North East of England</p>

51
Q

<p>Where is High Force waterfall?</p>

A

<p>Close to Forest-in-Teesdale on the River Tees</p>

52
Q

<p>Where is the<strong>mouth</strong>of the River Tees?</p>

A

<p>Middlesbrough. It flows into the North Sea</p>

53
Q

<p>Where is the<strong>source</strong>of the River Tees?</p>

A

<p>Pennine Hills nearCross Fell (height 893m)</p>

54
Q

<p>Name<strong>4physicalcauses</strong>of<strong>flooding</strong></p>

A
<ul>
	<li>Heavy/Prolonged precipitation</li>
	<li>Snowmelt</li>
	<li>Relief (steep slopes)</li>
	<li>Geology</li>
</ul>
55
Q

<p>Name<strong>3human causes of flooding</strong></p>

A
<ol>
	<li>Urbanisation</li>
	<li>Deforestation</li>
	<li>Agriculture</li>
</ol>
56
Q

<p>What is a<strong>hydrograph</strong>?</p>

A

<p>Agraph showing how a river responds to a storm, showing the rainfall and discharge over time</p>

57
Q

<p>What is a '<strong>flashy</strong>' hydrograph?</p>

A

<p>A hydrograph with a<strong>short lag time</strong>and a<strong>high peak discharge</strong></p>

58
Q

<p>What is a '<strong>flat</strong>' hydrograph?</p>

A

<p>A hydrograph with a<strong>long lag time</strong>and a<strong>low peak discharge</strong></p>

59
Q

<p>How is river<strong>discharge</strong>measured?</p>

A

<p>Volume × Velocity</p>

<p>Cubic metres per second (cumecs)</p>

60
Q

<p>Which<strong>factors</strong>influence the<strong>shape</strong>of a flood<strong>hydrograph</strong>?</p>

A

<ul><li>Basin size</li><li>Drainage density</li><li>Rock type</li><li>Land use</li><li>Relief</li><li>Rainfall intensity</li></ul>

61
Q

<p>What is '<strong>lag time</strong>'?</p>

A

<p>The time between<strong>peakrainfall</strong>and<strong>peakdischarge</strong>on a hydrograph</p>

62
Q

<p>What is<strong>antecedent</strong>rainfall?</p>

A

<p>The amount of rain that has already fallen prior to a specific event</p>

63
Q

<p>Define '<strong>interception</strong>'</p>

A

<p>Leaves and tree branches catch rainfall and prevent it from running into the river</p>

64
Q

<p>Define '<strong>infiltration</strong>'</p>

A

<p>Rain that soaks into the top layers of the soil and rock below</p>

65
Q

<p>What is<strong>impermeable</strong>rock?</p>

A

<p>Rock which water is not able to flow through</p>

66
Q

<p>What is<strong>permeable</strong>rock?</p>

A

<p>Rock which water is able to flow through</p>

67
Q

<p>Define<strong>surfacerunoff</strong></p>

A

<p>Water runs over the top of ground which is very hard <em><strong>(i.e. baked soil or concrete</strong></em>) or very wet <em><strong>(saturated)</strong></em> ground.</p>

<p>Surface run off occurs when<strong>no</strong>water can infiltrate into the ground</p>

68
Q

<p>What is<strong>hardengineering</strong>?</p>

A

<p>Building structures to deal with natural hazards, such as dams to prevent flooding</p>

69
Q

<p>Name a range of<strong>hard engineering</strong>stategies used to manage river<strong>flooding</strong>?</p>

A
<ul>
	<li>Reservoirs and dams</li>
	<li>Channel straightening</li>
	<li>Embankments</li>
	<li>Flood relief channels</li>
</ul>
70
Q

<p>What is<strong>soft engineering</strong>?</p>

A

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

71
Q

<p>Name a range of<strong>softengineering</strong>strategies used to manage river flooding?</p>

A
<ul>
	<li>Afforestation</li>
	<li>Land use zoning</li>
	<li>River restoration</li>
	<li>Wetland restoration</li>
	<li>Flood warnings</li>
</ul>
72
Q

<p>How do<strong>dams</strong>regulate water flow?</p>

A

<p>Durings periods of high rainfall, water is stored in the dam</p>

<p>Water is released when rainfall is low</p>

73
Q

<p>Why is building<strong>dams controversial</strong>?</p>

A

<ul><li>They are very expensive</li><li>Land is flooded to create the reservoir</li><li>People are relocated to make way for the dam</li></ul>

74
Q

<p>What are the<strong>benefits</strong>of<strong>dams</strong>?</p>

A

<ul><li>They are multi purpose - so they can be used to generate HEP as well as manage river flow</li><li>They are affective holding back water in times of potential flood</li><li>They are long lasting</li></ul>

75
Q

<p>Most dam schemes are<strong>multi-purpose</strong>. What are their main functions?</p>

A
<ul>
	<li>Flood prevention</li>
	<li>Irrigation</li>
	<li>Water supply</li>
	<li>Hydro-electric power generation</li>
	<li>Recreation e.g. sailing</li>
</ul>
76
Q

<p>What is<strong>channel straightening</strong>?</p>

A

<p>Cutting through meanders to create a straight channel to speed up water flow</p>

77
Q

<p>What are the<strong>advantages</strong>of channel straightening?</p>

A

<p>It moves water out of an area quickly as water passes through a straight channel quicker than a meandering channel</p>

78
Q

<p>Why is<strong>channelstraighteningproblematic</strong>?</p>

A

<p>It may increase the risk of flooding further downstream</p>

79
Q

<p>What are<strong>river embankments</strong>?</p>

A

<p>Raised riverbanks which allow the river channel to hold more water and prevent flooding</p>

80
Q

<p>What are the<strong>advantages</strong>of river embankments?</p>

A

<p>Embankments increase the volume of water that the river can hold, reducing the risk of flooding</p>

81
Q

<p>What are the<strong>problems</strong>with<strong>embankments</strong>?</p>

A

<p>Not always effective. Water can rise above the embankments, causing flooding</p>

82
Q

<p>What are<strong>floodreliefchannels</strong>?</p>

A

<p>A man-made river channel constructed to by-pass an urban area</p>

83
Q

<p>What are the<strong>benefits</strong>of<strong>floodreliefchannels</strong>?</p>

A

<p>River discharge can be controlled by using gates to control water levels</p>

84
Q

<p>What are the<strong>disadvantages</strong>of flood relief channels?</p>

A

<p>Increased levels of flooding could occur where the diverted water re-enters the river</p>

85
Q

<p>How does<strong>floodplain zoning</strong>work?</p>

A

<ul>
<li>It restricts different land uses to certainlocations on the floodplain</li>
<li>Expensive/important landuses are placed further away from the river e.g. housing and industry</li>
<li>Low value uses are placed close to the river e.g. pasture and parkland</li>
</ul>

86
Q

<p>What are the<strong>advantages</strong>of flood plain zoning?</p>

A

<p>Consideration into the landuse around the river is taken which means concrete surfaces are not used, reducing impermeable surfaces close to river. Less damage occurs as important facilities are located futher away</p>

87
Q

<p>What are the<strong>disadvantages</strong>of flood plain zoning?</p>

A

<p>It limits the uses of land closes to a river</p>

<p>It is almost impossible to use flood plain zoning on land that has already been built on</p>

88
Q

<p>What is<strong>riverrestoration</strong>?</p>

A

<p>Making the river more natural. For example:</p>

<ul>
<li>When rivers have previously been artificially starightened they are returned to their original course.</li>
<li>Removing levees so that the river floods naturally</li>
</ul>

<p>The purpose of this is to prevent flooding further downstream</p>

89
Q

<p>What are the<strong>benefits</strong>of<strong>river restoration</strong>?</p>

A
<ul>
	<li>Less risk of flooding downstream</li>
	<li>Limited maintenance needed</li>
	<li>Creates habitats for birds</li>
</ul>
90
Q

<p>What are the<strong>problems</strong>with<strong>river restoration</strong>?</p>

A

<ul>
<li>Flooding can increase</li>
<li>Major floods are more likely unless planning takes place</li>
</ul>

91
Q

<p>How does<strong>afforestation</strong>help manage river flooding?</p>

A

<p>Planting trees to intercept and absorb water reduces surface run off</p>

92
Q

<p>Who issues<strong>flood warnings</strong>in England and Wales?</p>

A

<p>The Environment Agency</p>

93
Q

<p>What are the<strong>3 levels of flood warnings</strong>?</p>

A
<ol>
	<li>Flood Watch</li>
	<li>Flood Warning</li>
	<li>Severe Flood Warning</li>
</ol>
94
Q

<p>What would people be encouraged to do by theEnvironment Agency to<strong>prepare</strong>for a flood?</p>

A

<ol>
<li>Plan what to do eg.move possessions upstairs</li>
<li>Use flood gates to prevent water entering their property</li>
<li>Use sandbags to keep floodwater away from buildings</li>
</ol>

95
Q

<p>Name a example of a flood management scheme in the UK</p>

A

<p>Morpeth Flood Scheme - River Wansbeck</p>

96
Q

<p>Why does the town of Morpeth, on the River Wansbeck,need a flood management scheme?</p>

A

<ul>
<li>The river valley is narrow and steep leading to high levels of suface run off in times of high rainfall</li>
<li>Increasing levels of wetter weather exacerbate the flood risk</li>
<li>High cost of damage from previous flood events</li>
</ul>

97
Q

<p>What was done to<strong>manage</strong>flooding in Morpeth?</p>

A

<ol>
<li><strong>Lowford Bridge tree catching poles</strong>- to cacth debris and prevent it flowing downstream, and blocking bridges</li>
<li><strong>Mitford Dam</strong>- can hold back 1.3 million cubic metres of water, reducing flow to town centre</li>
<li>Improved existing flood defences</li>
<li>Flood gates set up- and designated flood warden to close gates at times of flood</li>
</ol>

98
Q

<p>Describe the<strong>socialissues</strong>(+ and -) arising from the Morpeth flood management scheme</p>

A

<p>+ Local people were consulted over defences</p>

<p>+ Residents on Mitford Housing Estate were paid compensation for Mitford Dam being built</p>

<p>-... this caused conflict with other locals</p>

<p>- Some houses on Wansbeck street (close to river) have not been defended</p>

99
Q

<p>Describe the<strong>economicissues</strong>(+ and -) arising from the Morpeth flood management scheme</p>

A

<p>-/+ The Morpeth FloodActionGroup are working toreduce insurancepremiums for people livingnear the river</p>

<p>-Cost of the scheme was£25 million,£5 million overthe original estimate</p>

100
Q

<p>Describe the<strong>environmentalissues</strong>(+ and -) arising from the Morpeth flood management scheme</p>

A

<p>+In Jan 2016, StormDesmondbrought highriver levels to the town.The flood defences held upand theflood gatewasused.​</p>

<p>+ Thenative white clawedcrayfish has been movedby hand to a new locationin the River to ensure it isconserved.​</p>

<p>+The flood walls weredesigned sothey fitted thehistoric image of the town​</p>

101
Q

<p>What are the 3 types of weathering?</p>

A

<ul><li>Chemical Weathering</li><li>Biological Weathering</li><li>Mechanical Weathering</li></ul>

102
Q

<p>What is biological weathering?</p>

A

<p>Biological weathering is when roots of plants gorw inside rocks, forcing the rocks to crack and break apart</p>

103
Q

<p>What is Chemical Weathering?</p>

A

<p>Chemical Weathering is when the slightly acidic rainwater causes a chemical reaction on the rock, which wears it down</p>

104
Q

<p>What is Mechanical Weathering?</p>

A

<p>Mechanical weathering is when water gets into the cracks of rock. As temperatures drop, the water expands which cracks the rock. This continually occurs until thethe rock is completely broken off</p>

105
Q

<p>How are <b>Gorges and Waterfalls</b> formed?</p>

A

<ul><li>A river erodes the less resistant rock, creating a notch in the softer rock, which creates a river rapid</li><li>Overtime, more of the softer rock gets eroded leaving the hard rock sticking out above the soft rock</li><li>The height of the drop increases as the water erodes the soft rock at the bottom, creating a waterfall</li><li>The process fo <b>undercutting</b> occurs, where the less resistant rock starts to be eroded underneath the hard rock</li><li>The overhanging hard rock eventually collapses due to there not being enough support</li><li>The hard drock and the soft rock base erode through <b>abrasion</b> which creates a <b>plunge pool</b></li><li>This keeps continuing and the waterfall receeds upstream and if the process is repeated multiple times, agorge may form</li></ul>

106
Q

<p>What are <b>flood plains</b>?</p>

A

<p>Flood Plains are wide areas of flat land that surround a river in their lower course at the bottom of a vally. These areas are succeptible to flooding</p>

107
Q

<p>What are <b>point bars</b>?</p>

A

<p>Point Bars are a <b>cresent-shaped</b> landform that is made up of deposited material that accumulates on the <b>inside bend</b> of a river meander</p>

108
Q

<p>How are <b>Ox-Bow Lakes</b> formed?</p>

A

<ul><li>As erosion continues, the meanders in the river get closer to each other and create a <b>swan's neck meander</b> - a small piece of land between bends</li><li>During a flood, high energy water will breach the neck of the meander</li><li>This makes the river flow straighter and have a faster course</li><li>Over time, deposits fill in the meander bends</li><li>The meander cuts off from the river, which forms an ox-bow lake</li></ul>

109
Q

<p>What does <b>lateral erosion</b> do?</p>

A

<p>Lateral erosion makes the river wider</p>

110
Q

<p>Which part of a river does lateral erosion occur?</p>

A

<p>Lateral Erosion occurs in the lower and middle courses of a river</p>

111
Q

<p>What does <b>vertical erosion</b> do?</p>

A

<p>Vertical erosion makes the river valley deeper</p>

112
Q

<p>Where does vertical erosion occur?</p>

A

<p>Vertical erosion occurs in the upper courses of a river</p>

113
Q

<p>How are flood plains formed?</p>

A

<p>Flood Plains are formes by meander migration close to the mouth of the river</p>

114
Q

<p></p>

A

<p></p>