Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

geography > 5.1 - The operation and importance of the hydrological cycle > Flashcards

5.1 - The operation and importance of the hydrological cycle Flashcards

You may prefer our related Brainscape-certified flashcards:
U.S. Geography flashcards World Geography flashcards
1
Q

what type of system is the hydrological cycle

A

closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the global hydrological cycle?

A

A closed system of never ending water circulation driven by solar energy and gravitational potential energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a store?

A

Reservoirs where water is held e.g. the ocean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a flux?

A

The rate of flow between stores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a process?

A

The physical mechanisms which drive the fluxes of water between the storesy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the cryosphere?

A

Areas of the Earth where water is frozen into snow or ice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is blue water?

A

Water stored in rivers, streams, lakes and groundwater in liquid form (visible part of the hydrological cycle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is green water?

A

Water stored in the soil and vegetation (invisible part of hydrological cycle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the main global water stores?

A

Oceans, icecaps, groundwater, rivers/lakes, soil moisture and atmospheric moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name the 2 sources that power the global hydrological cycle

A

Solar energy: in the form of heat

Gravitational potential energy: causes rivers to flow downhill and precipitation to fall to the ground.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the 4 main stores

A

the oceans (largest by far)

glaciers and ice sheets (cryosphere, second largest)

surface runoff- land-based stores, including rivers, lakes, groundwater and the moisture held in soils and vegetation.

the atmosphere
Of the freshwater stores:
The cryosphere is the largest, holding 69% of global freshwater
Groundwater holds 30%
Less than 1% is stored in the biosphere (vegetation and soil moisture)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are flows

A

transfers of water from one store to another.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is residence time?

A

The average time a water molecule spends in a reservoir or store

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is fossil water?

A

Ancient groundwater formed as the result of former pluvial periods. Not renewable or reachable for human use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is precipitation?

A

The movement of water in any form from the atmosphere to the ground

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is evaporation?

A

The change in state of water from a liquid to a gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is transpiration?

A

The diffusion of water from vegetation to the atmosphere, involving a change from a liquid to a gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is groundwater flow?

A

The slow transfer of percolated water underground through pervious or porous rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How much water is available to humans?

A

Only 2.5% of Earth’s water is freshwater, and 69% of this is locked up in the cryosphere, whilst 30% occurs as inaccessible groundwater. This leaves only 1% of fresh water easily accessible for human use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What store has the longest/shortest residence time?

A

Ice sheets (800,000 to 1 million years) and groundwater (10,000 years) have the longest. Atmospheric moisture is the shortest (about ten days)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why is the hydrological cycle a closed system?

A

There are no external inputs or outputs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a drainage basin

A

Subsystem within global hydrological cycle, the area of land drained by a river and its tributaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is a drainage basin an open system?

A

Has external inputs and outputs that cause the amount of water in the basin to vary over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a watershed?

A

The highland which divides and separates waters flowing to different rivers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What 3 conditions are needed to form precipitation?

A

air cooled to a saturation point with relative humidity of 100%

condensation nuclei

temperature below dew point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is condensation?

A

The change from a gas to a liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is dew point?

A

The temperature at which dew forms, measure of atmospheric moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the 6 key influencing factors on drainage basin inputs?

A

amount of precipitation

type of precipitation

seasonality

intensity of precipitation

variability

distribution of precipitation within a basin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is interception?

A

The process by which water is stored in the vegetation

30
Q

How does convectional rainfall form/where is it found?

A

When the land becomes hot due to the sun,

-> air above it becomes warmer, expands and rises.

->As it rises, the air cools, condenses -> clouds &condensation

  • Associated with intense thunderstorms - areas such as Tropics and continental interiors
31
Q

How does orographic rainfall form and where is it found?

A

when air is forced to rise over a geographical barrier (mountain)

-> it cools, condenses -> forms rain

Happens in areas where there are mountains e.g. Himalayas

32
Q

How does cyclonic rainfall form and where is it found?

A

when warm air ( lighter & less dense) is forced to rise over a cold denser air

As it rises, air cools and its ability to hold water vapour decreases -> condensation and clouds.

Happens in UK

33
Q

What is infiltration?

A

The process by which water soaks into or is absorbed by soil

34
Q

What is infiltration capacity?

A

The maximum rate at which rain can be absorbed by a soil at a given condition
Expressed in mm/hr

35
Q

What is surface run off?

A

The movement of water that is unconfined by a channel across the surface of the ground - also known as overland flow

36
Q

What factors affect infiltration?

A

amount of water already in soil (antecedent soil moisture)
soil texture
type, amount and seasonal changes in vegetation cover
slope angle

37
Q

What are key flows and transfers in the drainage basin?

A

overland flow
throughflow
percolation
saturated overland flow
groundwater flow
channel flow

38
Q

What is throughflow?

A

The lateral transfer of water downslope through the soil via natural pipes and percolines

39
Q

What is percolation?

A

The transfer of water from the surface or from the soil into the bedrock beneath

40
Q

What is saturated overland flow?

A

The upward movement of water into the evaporation zone

41
Q

What is evaporation?

A

The physical process by which moisture is lost directly into the atmosphere from water surfaces and soil

42
Q

What factors influence evaporation rates?

A

Climatic: temperature, hours of sunshine, humidity, wind speed
Other: size of water body, depth of water, water quality, type of vegetation cover, colour of surface

43
Q

What is EVT and PEVT?

A

Evapotranspiration is the combined effect evaporation and transpiration - most important aspect of water loss to atmosphere
PEVT = potential EVT, water loss that would occur if there was an unlimited supply of water in the soil for use by vegetation

44
Q

What are the physical factors affecting the drainage basin cycle?

A

climate
soils
geology
relief
vegetation

45
Q

How can humans impact on precipitation?

A

Cloud seeding - introduction of silver iodide pellets or ammonium nitrate to act as condensation nuclei to attract water droplets

-> aim; to ^ rainfall in drought-stricken areas

46
Q

How can humans impact on evaporation and EVT?

A

-through changes in land use

-deforestation
-afforestation

->increases surface runoff, increasing flooding

47
Q

How can humans impact on infiltration and soil water

A
48
Q

How can humans impact on interception

A

-deforestation
-afforestation -> ^ in runoff, sediment loss due to soil compaction when planting the young trees

as interception is largely determined by vegetation type

49
Q

What is deforestation

A

cutting down & removal of trees in a forested area

50
Q

What is an aquifer

A

underground reservoir

51
Q

What is afforestation

A

planting of trees in an area that has not been forested in recent times

52
Q

How can humans impact on infiltration and soil water?

A

-change in land use from forest -> farmland -> ^ soil compaction -> rain cant soak into ground -> stays on surface -> runoff -> erosion

-grazing cows -> soil compaction -> trampling of animals -> aeriating soil

53
Q

How can humans impact on groundwater?

A

Human use of irrigation -> declining water table levels in aquifers. Too much groundwater abstraction

54
Q

Name the 4 impacts humans have on the drainage basin

A

-overabstraction -> abstracting ^ water from groundwater reserves -> rivers drying during low rainfall

-deforestation -> reduced trees -> soil compaction -> rain stays on surface -> runoff -> erosion -> flooding
-> reduced evapotranspiration, interception

-changing land use - urbanisation -> impermeable surfaces -> alter flow of water -> reduces infiltration, interception, evapotranspiration, ^ runoff

-reservoirs -> man-made storage reservoirs -> delay flows

55
Q

What is a water budget?

A

The balance between precipitation, evaporation and run off

56
Q

What formula can be used to express drainage basin water budgets?

A

P = Q + E ± S
P = precipitation
Q = discharge
E = EVT
S = changes in storage

57
Q

How does a water budget change throughout the year (seasons)?

A

winter months -> precipitation exceeds PEVT -> soil moisture surplus for plants

spring -> PEVT exceeds P -> soil moisture utilisation occurs, precipitation is used up.

-> soil moisture is now used up

-> summer months -> soil water deficiency as water is used up, and PEVT exceeds P still

-> winter months -> P exceeds PEVT -> soil water starting to fill again

-> end of december -> soil water store is now full -> field capacity has been reached

58
Q

What is a river regime?

A

The annual variation in discharge or flow of a river at a particular point or gauging station

usually measured in cumecs.

59
Q

What 6 factors affect river regime character?

A

-size of river, where measurements are taken

amount, pattern and intensity of precipitation

temperature

geology and soils

amount and type of vegetation

human activities such as dam building

60
Q

What is a storm hydrograph?

A

A graph to show the variation of discharge within a short period of time, normally an individual storm or group of storms not more than a few days in length

61
Q

What is the rising limb?

A

The part of a storm hydrograph in which the discharge starts to rise

62
Q

What is peak discharge?

A

The time when the river reaches its highest flow

63
Q

What is lag time?

A

The time interval between peak rainfall and peak discharge

64
Q

What is the falling limb?

A

The part of the storm hydrograph in which the discharge starts to decrease

65
Q

What is base flow?

A

The normal day to day discharge of the river

66
Q

What does a ‘flashy’ river storm hydrograph look like?

A

Short lag time, high peak, steep rising limb

67
Q

What factors create a ‘flashy’ storm hydrograph?

A

Intense storm which exceeds infiltration of soil, impermeable rocks, low infiltration rate, high steep slopes, circular basin, urbanisation, high drainage density, bare vegetation

68
Q

What does a ‘flat river’ storm hydrograph look like?

A

Long lag time, low peak, gently sloping rising limb

69
Q

What factors create a ‘flat river’ storm hydrograph?

A

Steady rainfall less than the infiltration capacity of the soil, permeable rocks, low gentle slopes, low drainage density, elongated basin, low population density, dense vegetation

70
Q

What are the 4 impacts of urbanisation on hydrological processes?

A

building exposes soil and increases overland flow

tarmac surfaces are impermeable

drains and sewers reduce distance storm water must travel before reaching a channel

bridges restrain free discharge of floodwaters, act as local dams for upstream floods

71
Q

Give 3 examples of sustainable drainage systems introduced to reduce runoff produced from rainfall

A

-permeable pavements -> delay runoff by using gaps in pavement slabs

-wetlands -> retention areas with marsh vegetation

-green roofs

geography (55 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions