Geography: Water cycle, water insecurity Flashcards Preview

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Flashcards in Geography: Water cycle, water insecurity Deck (50)
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1
Q

Name an input of the hydrological cycle

A

land precipitation

2
Q

name some stores in the hydrological cycle (3)

A

rivers/lakes
ocean
atmosphere

3
Q

name 3 flows in the hydrological cycle

A

ocean to land water vapour transport
surface flow
groundwater flow

4
Q

name 3 outputs of the hydrological cycle

A

ocean evaporation
ocean precipitation
evaporation/transporation

5
Q

what is a drainage basin?

A

an area of land drained by a river and its tributaries, seprated from other drainage basins by a ridge of land called a watershed.

6
Q

which physical factors affect drainage basin flows? explain each

A
  • interception: leaves and vegetation intercept rainfall. this can result in more evaporation, dry leaves and shoots can also absorb and store precipitation.
  • direct runoff (overland flow): the ground becomes saturated, forcing rainwater to run off the surface. this quickly delivers water to river channels.
  • infiltration and throughflow: infiltration is the movement of water downwards through the soil. the rate of infiltration depends on the amount of water already in the soil. it can then flow downwards towards a river through the soil.
  • percolation and groundwater flow: percolation is the movement of water through permeable rocks. groundwater flow happens as water travels through rocks in the ground.
7
Q

which human factors affect the drainage basin? explain each

A
  • deforestation: less roots in the soil makes it less permeable, less water can be stored there as a result.
  • Urbanisation: more man-made materials such as concrete are impermeable. this increases surface runoff.
  • reservoirs: interrupt the travel of water. delays flows through a drainage basin and adds to the amount of water lost through evaporation.
8
Q

What is potential evapotranspiration?

A

the maximum amount of water that can be lost through evapotranspiration in an endless supply of water in surface water stores.

9
Q

what is economic water insecurity?

A

when water resources are available but there’s insufficient capital to meet the demand.

10
Q

what is a storm hydrograph?

A

shows change in a river’s discharge at a given point on a river over a short period of time.

11
Q

what are the 4 types of drought?

A
  • meteorological
  • agricultural
  • hydrological
  • socio-economic
12
Q

why are the sub-tropics more affected by drought than anywhere else?

A

intense solar radiation at the equator warms the air, causing convection. the subtropical high pressure zone forms when hot air from the equator rises and forms a belt of high pressure. this results in clear skies and dry, hot temperatures.

13
Q

what does a river regime show?

A

the annual variation in the discharge of a river

14
Q

what are the causes of drought in the Sahel?

A
  • deficiency of rain
  • the monsoon is patchy and irregular
  • monsoon weakened as there’s no temperature difference between the land and sea.
15
Q

how do humans increase drought risk?

A
  • irrigation
  • over abstraction
  • deforestation
  • climate change
16
Q

what are the differences between simple and complex river regimes?

A

SIMPLE REGIMES: river experiences seasonally high discharge, followed by low discharge

COMPLEX REGIMES: larger rivers cross several different relief and climatic zones, and therefore experience the effects of these events.

17
Q

what is the ITCZ?

A

a belt of low atmospheric pressure located around the equator.

18
Q

what is soil moisture recharge?

A

when water is added to soil following a period of soil moisture defecit.

19
Q

what are the general processes taking place on the atmospheric circulation model?

A
  • The most intense sunlight hits the equator, causing air to heat up and rise.
  • This forms an area of low pressure at the equator.
  • Air rises and moves away from the equator, the air then falls and moves back towards the equator, forming trade winds.
  • At the equator, air moves in Hadley cells.
  • Trade winds meet at the ITCZ to cause alternating wet and dry conditions at the tropics.
  • It also means that the equator has dry, arid conditions.
  • Warmer air moves towards the polar front, cools and falls at the poles, air then begins to move back towards the equator in the polar cells.
20
Q

What are the causes of drought in the Sahel?

A
  • deficiency of rain
  • monsoon is patchy and irregular.
  • change in temp. of surrounding oceans means that the monsoon remains south.
  • ENSO can produce a cold atlantic current which reduces evaporation, results in less evaporation.
21
Q

What is a monsoon and what are the effects?

A
  • a monsoon is a seasonal change in the direction of prevailing winds of a world region.
  • moist air from oceans brings humid air and torrential rain.
22
Q

What is an accluded front?

A

a cold and warm front combined

23
Q

How do atmospheric processes contribute to drought in California?

A
  • precipitation has fallen by 80%

- Decrease in winter storm activity

24
Q

How do processes on land contribute to drought in California?

A
  • surface runoff and soil moisture has declined.
  • snow pack levels at a record low in 2015
  • forested areas have reverted to scrub grassland.
  • reservoir levels have fallen, in October 2013, storage was 77% of the average for the time of year.
25
Q

What is ENSO and how does it affect water availability?

A

EL NINO
appearance of warm water from time to time in the eastern equatorial pacific

LA NINA
the development of colder than average surface temperatures in the eastern equatorial pacific.

el nino: increased precipitation in the EEP
la nina: decreased precipitation in the EEP

26
Q

What is desalinisation and what are the advantages and disadvantages of it?

A

ISRAEL

ADVANTAGES:

  • Israel produces more water than any country in the world.
  • Israel currently is in water surplus, reducing the chances of water shortages in the future.

DISADVANTAGES:
-brine that’s produced from the desalinization process is dumped in the ocean.

27
Q

What is holistic management?

A

water management which involves the environment as well as local people etc.

28
Q

What is integrated water resource management?

A

a process which promotes the co-ordinated development and management of water, land and related resources in a sustainable way.

29
Q

Describe Egypt’s role in managing the Nile.

A
  • Egyptian govt. is trying to resolve the situation. There isn’t enough water to support its growth. Its demand is also increasing as its population has increased by 40% since 1990.
  • the president attempted to solve the problem in the 1990s by pumping water to remote parts to encourage economic growth and reduce overcrowding.
  • the govt. has shown farmers how to reclaim land.
30
Q

how is the global hydrological cycle a closed system and where does the power that drives it come from?

A

it’s a closed system as there are no external inputs or outputs.

power that drives the cycle comes from solar energy and gravitational energy.

31
Q

what is the global water budget?

A

all of the water held in stores and flows of the hydrological cycle.

32
Q

how is the drainage basin an open system and what are the inputs, flows and outputs?

A

open system as it has external inputs and outputs.

INPUT
the main input is precipitation

FLOWS:

  • interception
  • infiltration
  • percolation
  • throughflow
  • channel flow

OUTPUTS:

  • evaporation
  • transpiration
  • channel flow into another basin
33
Q

what is a river regime?

A

annual variation in discharge or flow at a particular point.

34
Q

how does urbanization increase flood risk?

A
  • construction leads to removal of vegetation cover, increases overland flow.
  • soil replaced by concrete, increases surface runoff.
  • channelization of rivers means that they can’t hold as much water, making it more likely for the river to burst its banks
35
Q

which actions are involved in flood risk management?

A
  • strengthening embankments of streams and rivers.
  • putting flood emergency procedures in place
  • steering urban development away from high-risk areas.
36
Q

how does el nino cause drought?

A
  • cool water normally found along the coast of peru is replaced by warmer water.
  • warm water normally found near Australia is replaced by cool water.
  • can trigger dry conditions throughout the world as monsoon rains in India and SE Asia often fail.
37
Q

what causes an el nino year?

A
  • air circulation loop is reversed
  • disrupted trade winds reverse the direction of warmer water. trade winds can be slackened or even reversed
  • has a knock-on effect on ocean currents
38
Q

what is a la nina year and how can it cause drought?

A
  • involves the build up of cooler-than-usual subsurface water in the tropical part of the pacific.
  • can lead to drought on the western coast of south America due to less evaporation and precipitation
39
Q

what is the impact of drought on wetlands?

A
  • less precipitation, less interception, infiltration and percolation.
  • water tables fall, evaporation increases. this reduces the valuable functions performed by wetlands.
40
Q

how can flooding have a positive effect on the environment?

A
  • recharges groundwater stores.
  • increased connectivity between aquatic habitats.
  • soul moisture replenishment.
41
Q

what are the impacts of climate change on inputs and outputs?

A

PRECIPITATION:

  • warmer atmosphere has a larger water-holding capacity.
  • precipitation increases in the tropics and high latitudes.
  • more precipitation in northern regions falls as rain rather than snow.
  • increased evaporation and transpiration
  • where precipitation will increase, it’s also likely that soil moisture will also increase.
42
Q

what are the impacts of climate change on stores and flows?

A
  • increased surface runoff, reduced infiltration.
  • thawing of permafrost releases methane.
  • spring snowmelt starts earlier, causing flooding.
  • glacial retreat, less storage
43
Q

why is water demand increasing?

A
  • population growth
  • economic development results in more industry, requires more water.
  • increasing living standards, more water used in the home and for recreation.
44
Q

what is the difference between physical and economic water scarcity?

A

Physical scarcity: when more than 75% of a country or region’s blue water flows are being used.

economic scarcity: when the use of blue water sources are limited by a lack of money/technology.

45
Q

how does agriculture result in water shortages?

A
  • irrigation

- recreation (swimming pools etc.)

46
Q

how is water conflict likely to happen in the Nile?

A
  • 300 million live within the Nile basin.
  • population set to double by 2030
  • also used to generate HEP
  • dams and barrages built in sudan and Ethiopia deprive Egypt of water.
47
Q

name some hard engineering schemes used to reduce the extent of water scarcity. describe them

A

water transfers: diversion of water from one drainage basin to another.

mega dams: nearly 60% of the world’s rivers are impeded by large dams. can disrupt the flow of water downstream but it stores water.

desalinization: classed as a hard engineering solution due to its inputs, but is a sustainable process. uses saltwater to make drinking water using reverse osmosis.

48
Q

name some sustainable water management schemes. describe each.

A
  • drip irrigation: reduces water losses by irrigation

- rainwater harvesting: often seen in African countries, jars collect rainwater which can be used for drinking.

49
Q

what is integrated drainage basin management?

A

based on achieving close co operation between basin users and players. works well on a local scale.

50
Q

name and describe some water-sharing treaties.

A
  • UN water courses convention offers guidelines for the use of transboundary rivers.
  • EU water framework directive ensures that all members keep their water bodies in good condition, including their marine waters.