Water Cycle and Water Insecurity

Question 1

Describe the hydrology in polar regions

Answer 1

• 85% radiation reflected
• permafrost - impermeable
• rapid runoff in spring

Question 2

describe hydrology in tropical rainforests

Answer 2

• dense vegetation consumes most precipitation

- limited infiltration

Question 3

2 processes that drive the hydrological cycle

Answer 3

• solar energy
  the more heat = more evaporation = more precipitation
• gravitational potential energy
  keeps water moving inputs, outputs, stores, and flows

Question 4

what are stores, fluxes, and processes

Answer 4

store - water is held
flux - the rate of flow of water
processes - physical factors that drive fluxes

Question 5

residence time

Answer 5

average time water molecules remain in a store

Question 6

what is a drainage basin

Answer 6

subsystem - open system with many inputs and outputs

Question 7

physical factors affecting drainage basin

Answer 7

• climate - evaporation and precipitation
• soils - determine infiltration
• geology - permeable rocks infiltrate
• relief - slopes increase runoff
• vegetation - transpiration and interception

Question 8

human factors affecting drainage basin

Answer 8

deforestation
over-abstraction
pollution
global warming

Question 9

why does groundwater extraction negatively affect a drainage basin?

Answer 9

• water extracted at a faster rate than it is recharged

also reduces storage

Question 10

dam construction and drainage basins

Answer 10

increases surface water and evaporation

reduce downstream flow and discharge

Question 11

what is a water budget?

Answer 11

the annual balance between inputs and outputs

shows when water naturally leaves and enter the system

Question 12

what does a water budget show?

Answer 12

• more than enough water (positive water balance)

- not enough water (negative water balance)

Question 13

what is a river regime

Answer 13

annual variation in discharge or flow of a river

Question 14

main factors affecting regime

Answer 14

• drainage basin size / capacity
• geology and relief
• land use
• precipitation and climate

Question 15

simple regimes

Answer 15

seasonally high discharge followed by a low discharge

Question 16

complex regimes

Answer 16

larger rivers that cross several different relief and climatic zones e.g. Mississippi or the Ganges

Question 17

2 examples of complex regimes and where they cross

Answer 17

river Nile - North Africa - Uganda, Ethiopia

Amazon - South America - Brazil, Ecuador

Question 18

what do storm hydrographs show

Answer 18

how river discharge varies after precipitation especially during storms.

Question 19

drought

Answer 19

an extended period of below-average precipitation

Question 20

meteorological drought

Answer 20

long-term precipitation lower than normal

affected by atmospheric conditions

Question 21

agricultural drought

Answer 21

not enough soil moisture - caused by precipitation shortages

Question 22

hydrological drought

Answer 22

surface water is deficient - occurs after meteorological and agricultural

Question 23

socio-economic

Answer 23

water demand outstrips water availability

Question 24

causes of Brazil drought 2014-2015

Answer 24

• over-abstraction of water supplies

- series of high-pressure systems diverted rain-bearing winds away from brazil - dry air

Question 25

impacts of Brazil drought

Answer 25

- water rationing for 4 million people - the halting of HEP - power cuts - depletion of reservoirs - reduced crops led to increased prices

Question 26

drought in the Sahel

Answer 26

- provided opportunity for re-greening the desert restoration technique - planting vegetation low costs reforesting water harvesting techniques naturally regenerating water shrubs and trees

Question 27

California and climate change

Answer 27

- severe mega-droughts wildfires due to droughts - 90% chance of decade long drought - increased evaporation and fall in precipitation

Question 28

impacts on California

Answer 28

- surface runoff and moisture levels decreased - forested areas reverted back to scrub and grassland - reservoir levels have fallen significantly

Question 29

ecosystem stress

Answer 29

constraints on the development or survival of ecosystems

Question 30

why is the amazon rainforest so important?

Answer 30

- earth's lungs absorb masses of Co2 - flying river in the sky - carries 17 million tonnes of water back to the Atlantic each day

Question 31

drought effects on rainforests

Answer 31

- younger trees die, reducing canopy cover which reduces humidity and therefore rainfall - larger risk of wildfires - sunlight on dying vegetation

Question 32

wetlands

Answer 32

areas where the soil is waterlogged with freshwater or salt-water

Question 33

importance of wetland

Answer 33

- rich biodiversity and cultural value - responsible for nutrient recycling - tourist attraction

Question 34

impacts of droughts on wetlands

Answer 34

- increased tree mortality - reduced habitats | - wildfires - cattle farmers burning old grass

Question 35

meteorological causes of droughts

Answer 35

UK - depressions causing low-pressure areas

Question 36

physical causes of flooding

Answer 36

- intense precipitation - sudden snowmelt - monsoon rainfall - vegetation - rock type - relief

Question 37

monsoon season in southeast Asia

Answer 37

- seasonal change in direction of prevailing winds - April and September - 70% rainfall in 100 days

Question 38

how do humans exacerbate flood risk

Answer 38

- changing land use - mismanagement of rivers - poor maintenance of rivers

Question 39

physical causes of storm desmond

Answer 39

- Atlantic low-pressure system (depression) - heavy rainfall as a result - jet streams - fast-moving air determining speed and direction of depressions

Question 40

human causes of storm desmond

Answer 40

- mismanagement of land - removal of trees for farming - hard engineering was not sufficient - mismanagement of rivers

Question 41

mitigating flood risk

Answer 41

- afforestation - restoring river channels - refusal of planning permission near rivers

Question 42

physical water scarcity

Answer 42

- not enough water to meet demands