Rivers Flashcards
1
Q
What is the hydrological cycle?
A
The hydrological cycle is a closed system where water is constantly recycled.
2
Q
What are stores in the hydrological cycle?
A
Stores are places where water is held for some time, including the atmosphere, surface stores, aquifers, ice and snow, and seas and oceans.
3
Q
What are surface stores?
A
Surface stores include puddles, lakes, rivers, and reservoirs.
4
Q
What is interception in the hydrological cycle?
A
Interception is how precipitation is prevented from reaching the ground, usually by being caught on leaves or branches.
5
Q
What are aquifers?
A
Aquifers are permeable rocks, such as limestone and sandstone, which can hold water.
6
Q
What are flows in the hydrological cycle?
A
Flows are how water is moved around the hydrological cycle.
7
Q
What is evaporation?
A
Evaporation is the change of water from a liquid to a gas (water vapour) due to heat from the sun.
8
Q
What is condensation?
A
Condensation occurs when water cools and changes from water vapour into a liquid, forming clouds.
9
Q
What is transpiration?
A
Transpiration is when plants release water vapour from their leaves.
10
Q
What is evapotranspiration?
A
Evapotranspiration is the combined transfer of water vapour from the Earth’s surface and plants.
11
Q
What is precipitation?
A
Precipitation is the transfer of water from the atmosphere to the Earth’s surface in the form of hail, sleet, snow, or rain.
12
Q
What is overland flow?
A
Overland flow is any water flowing across the Earth’s surface.
13
Q
What is infiltration?
A
Infiltration is when water moves down from the surface into the soil.
14
Q
What is percolation?
A
Percolation is the transfer of water down into rocks and aquifers.
15
Q
What is through flow?
A
Through flow is the movement of water through the soil between the groundwater store (water table) and the surface.
16
Q
What is groundwater flow?
A
Groundwater flow is the flow of water through rock.
17
Q
What is a drainage basin?
A
A major part of the hydrological system that drains all the water which lands on the Earth’s surface.
18
Q
Is a drainage basin an open or closed system?
A
A drainage basin is an open system.
19
Q
What makes each drainage basin unique?
A
Every drainage basin is different in shape and size, with different rock types, relief, and land use.
20
Q
What is a watershed?
A
The boundary between drainage basins.
21
Q
What is the source of a river?
A
The furthest point from the mouth where the river starts, which can be an upland lake, spring, or glacier.
22
Q
What is a confluence?
A
The place where two or more streams/rivers meet.
23
Q
What is a tributary?
A
A stream or river flowing into a larger stream or river.
24
Q
What is the mouth of a river?
A
Where the rivers enter the sea/ocean or sometimes a lake.
25
What is a channel network in a drainage basin?
A network of tributaries that connect to the main river channel.
26
What is drainage density?
The number of tributaries in a drainage basin.
27
What characterizes a drainage basin with high drainage density?
It has lots of tributaries.
28
What characterizes a drainage basin with low drainage density?
It has few tributaries.
29
Hydrological cycle
30
Drainage basin
31
What is erosion?
Erosion is the wearing down of surfaces.
32
What are the four erosion processes that change the shape of the river channel?
The four erosion processes are hydraulic action, abrasion, attrition, and corrosion.
33
What is hydraulic action?
Hydraulic action is the force of the water, which removes material from the bed and banks of the river.
34
What is abrasion?
Abrasion occurs when the materials carried by the river scrape away the banks and bed.
35
What is attrition?
Attrition is when the material being carried by the river hits each other, causing the pieces to become rounder and smaller.
36
What is corrosion (solution)?
Corrosion occurs when rocks are dissolved in slightly acidic water.
37
What are the two types of erosion in rivers?
The two types of erosion are vertical erosion and lateral erosion.
38
Where is vertical erosion dominant?
Vertical erosion is dominant in the upper course of rivers.
39
Where is lateral erosion dominant?
Lateral erosion is dominant in the middle and lower courses of rivers.
40
What are the four processes of transportation in rivers?
The four processes of transportation are traction, saltation, suspension, and solution.
41
What is traction?
Traction occurs when larger rocks and materials are rolled along the riverbed.
42
What is saltation?
Saltation is when smaller material, which can be lifted by the water, bounces along the riverbed.
43
What is suspension?
Suspension is when lighter material is carried within the river flow.
44
What is solution in the context of river transportation?
Solution occurs when materials are dissolved in the river water.
45
What is deposition?
Deposition occurs when a river does not have enough energy to carry materials, causing it to drop them.
46
What causes reduced energy in a river leading to deposition?
Causes include reduced discharge, decreased gradient, slower flow on bends, and when the river enters a sea, ocean, or lake.
47
What is the bedload?
The bedload is the heaviest material deposited first by the river.
48
What is alluvium?
Alluvium refers to lighter materials like gravel, sand, and silt that are carried further downstream.
49
What does the Bradshaw model summarize?
The Bradshaw model summarizes the changes in the character of a river as it moves downstream.
50
What are the long and cross profiles of a river?
All rivers have long and cross profiles that show changes in river characteristics from the source to the mouth.
51
What does the long profile of a river show?
The long profile shows the changes in the river gradient from the source to the mouth.
52
What are the characteristics of the upper course of a river?
The upper course is usually steep with uneven surfaces and has a narrow channel.
53
What are the characteristics of the middle course of a river?
The middle course has a deeper channel, gentle valley sides, and greater velocity than the upper course.
54
What are the characteristics of the lower course of a river?
The lower course is deeper, has flat floodplains, and carries mainly sediment and alluvium.
55
Types of erosion
56
Transportation
57
Deposition
58
Courses in a river
59
Lower course
60
Middle course
61
Upper course
62
What leads to changes in the river landscape?
Changes in river channel characteristics lead to changes in the river landscape.
63
What are the distinctive landforms in upland areas of rivers?
Waterfalls, gorges, V-shaped valleys, and interlocking spurs.
64
How do waterfalls form?
Waterfalls form when there is a drop in the river bed from one level to another, often due to changes in rock hardness.
65
What are the main erosional processes that create waterfalls?
Hydraulic action and abrasion.
66
What happens to the hard rock during waterfall formation?
The soft rock erodes quicker, undercutting the hard rock and creating a plunge pool.
67
What is the result of the overhang collapsing in waterfall formation?
It increases abrasion and makes the plunge pool deeper.
68
What type of erosion is dominant in the upper course of the river?
Vertical erosion.
69
What shape do valleys form due to vertical erosion?
V-shaped valleys.
70
What leads to the formation of interlocking spurs?
Erosion on the outside of the bend as the river channel starts to meander.
71
What happens to meanders downstream?
The size of the meanders increases.
72
What forms an oxbow lake?
When the river cuts through the neck of a meander during a flood, forming a straighter course.
73
What are floodplains?
Flat expanses of land on either side of the river.
74
How do levees form?
Heaviest material is deposited first, nearest to the river channel, forming natural embankments.
75
What are deltas formed from?
Deltas are formed when streams flow into standing bodies of water.
76
What is required for delta formation?
A large amount of sediment and a rapid drop in river velocity.
77
What processes increase deposition in delta formation?
Flocculation and bioconstruction.
78
What are some types of delta formations?
Arcuate and bird’s foot.
79
Waterfall
80
V shaped valleys
81
Interlocking spurs
82
Meanders
83
Ox bow lake
84
Floodplains and levees
85
Delta
86
What are the main river hazards?
The main river hazards are flooding and erosion.
87
What causes rivers to flood?
Rivers flood when the water in them reaches bankfull discharge and then overspills across the floodplain.
88
What are the main causes of flooding?
Flooding occurs as a result of heavy, torrential rain or a prolonged period of steady rain.
89
What happens during heavy, torrential rain?
High levels of overland flow occur because the water cannot infiltrate.
90
What happens during a prolonged period of steady rain?
The ground becomes saturated, leading to high levels of overland flow because the water cannot infiltrate.
91
What are other natural causes of river flooding?
Other causes include landslides, snow and ice melt, and storm surges.
92
What human activities increase the risk of flooding?
Urbanisation, deforestation, building of bridges and dams, human-induced climate change, and agriculture.
93
How are flooding and erosion related?
Flooding often goes hand in hand with erosion of the banks, as both result from increased discharge and velocity.
94
What are some hazards of flooding?
Hazards include the spread of water-related diseases, deaths and injuries, damage to transport routes, and loss of farmland.
95
How can flood waters spread diseases?
Flood waters may act as a breeding ground for disease-spreading animals like mosquitoes and may be contaminated by bacteria.
96
What are the economic impacts of flooding?
Increased insurance costs and lower house prices.
97
What opportunities do rivers provide?
Opportunities include rich silt for crops, a source of food, flat floodplains, easier construction, irrigation, leisure, tourism, electricity generation, and transport.
98
What human factor increases the risk of flooding due to deforestation?
Lack of trees reduces interception and infiltration, increasing overland flow.
99
How does urbanization contribute to flooding?
Impermeable concrete and tarmac increase overland flow as water flows into drains, reaching the river rapidly.
100
What agricultural practices increase the risk of flooding?
Bare soil and ploughing increase overland flow.
101
How does climate change affect flooding?
Rising global temperatures may increase storm frequency and intensity.
102
What physical factor related to relief increases flooding risk?
Steep slopes reduce infiltration and increase overland flow.
103
How does rock type influence flooding?
Impermeable rocks reduce percolation and increase overland flow.
104
What soil conditions increase the risk of flooding?
Frozen, saturated, or compacted soil reduces infiltration and increases overland flow.
105
How does weather contribute to flooding?
Heavy or prolonged rainfall means that the rate at which water reaches the surface exceeds the infiltration rate, leading to increased overland flow.
106
What seasonal variations affect flooding in Northern Europe?
Flooding tends to occur in the autumn and winter when rainfall is more frequent.
107
How does drainage density impact flooding?
Where drainage density is high, there are many tributaries taking water to the main channel, causing a rapid increase in discharge.
108
What role does vegetation play in flooding risk?
Where there is little natural vegetation, there is reduced interception leading to increased overland flow.
109
What is the key cause of flooding?
The amount and duration of precipitation; this cannot be altered.
110
What are the two main categories of flood management?
Hard engineering and soft engineering.
111
What does hard engineering involve?
Building structures or changing the river channel.
112
What is soft engineering?
Works with natural processes of the river and surrounding environment.
113
What is an example of soft engineering?
Mitigation schemes aim to minimise damage rather than trying to prevent flooding.
114
What are some types of hard engineering?
Dams and reservoirs, embankments, straightened channels, flood relief channels, spillways.
115
What is river restoration in soft engineering?
Restoring the river to its original regime—putting meanders back in, stabilising banks, and connecting to flood plains.
116
What is wetland conservation?
These areas provide somewhere for excess water to go and slow the flow of floodwater.
117
What does floodplain zoning involve?
Only certain land uses are allowed on the floodplain, reducing the risk.
118
What is afforestation?
The planting of vegetation and trees to increase interception and infiltration.
119
What additional methods can decrease flooding risk?
Leaving stubble on fields, contour ploughing, improved forecasting and flood warnings, dredging rivers.
120
What is the length of the Ganges River?
The Ganges is 2,510 km long.
121
Where does the Ganges River flow?
Through India and Bangladesh, where it becomes the River Padma.
122
What is the drainage basin area of the Ganges?
1.2 million km².
123
What is the population living within the Ganges drainage area?
Over 650 million people.
124
What is the length of the Brahmaputra River?
The Brahmaputra River is 3,969 km long.
125
What is the drainage basin area of the Brahmaputra?
651,334 km².
126
What opportunities do the Ganges and Brahmaputra rivers provide?
Water supply, agriculture, fishing, cultural significance, tourism, flat land for construction, and energy.
127
What hazards are associated with the Ganges/Brahmaputra drainage basin?
Regular floods, with significant events causing homelessness, crop destruction, and fatalities.
128
What human causes contribute to flooding?
Deforestation, human-induced climate change, urbanization, and agriculture.
129
What natural causes contribute to flooding?
Low-lying land, monsoon climate, tropical cyclones, and melting snow and ice.
130
What is the Flood Action Plan (FAP) in Bangladesh?
A plan funded by the World Bank to monitor flood levels, construct levées, build flood shelters, and improve flood warning systems.
131
What were some issues with the Flood Action Plan?
Inadequate funding, corruption, incomplete projects, and the need for maintenance.
132
What new management suggestions have been proposed?
Better flood forecasting and warning systems, more well-stocked flood shelters.
