Geography - WATER INSECURITY AND WATER CYCLE

Anticyclone

A system of high pressure, causing high temperatures and unseasonably high evaporation rates

Aquifer

A permeable or porous rock which stores water

Channel flow

Water flowing in a rivulet,stream or river

Convectional precipitation

Solar radiation heats the air above the ground, causing it to rise, cool & condense forming precipitation (often as thunderstorms). Often a daily occurrence. Most common in tropical climates.

Cryosphere

the global water volume locked in a frozen state

Depression

A system of low pressure, with fronts of precipitation where low and high pressure air masses meet.

Desalination plant

The conversion of seawater to freshwater, suitable for human consumption.

Desublimation

The change of state of water from gas to solid, without being a liquid (the opposite process to sublimation)

Drainage basin

area of land drained by a river and all its tributaries

Drainage density

The total length of all rivers & streams divided by the area of the drainage basin

Drought

An extended period of deficient rainfall relative to the statistical average for the region (UN)

Economic water scarcity

When water resources are available but insufficient economic wealth limits access to it

ENSO Cycles

El Nino Southern Oscillations - naturally occurring phenomena that involves the movement of warm water in the Equatorial Pacific.

Evapotranspiration

The combined total moisture transferred from the Earth to the atmosphere, through evaporation and transpiration

Frontal precipitation

Where air masses of different temperatures meet at a front, one mass will be forced over another, causing precipitation beneath the front.

Global hydrological cycle

The continuous transfer of water between land, atmosphere and oceans. The Earth is a closed system.

Groundwater flow

Water moving horizontally through permeable or porous rock due to Gravity

Hydrological drought

Insufficient soil moisture to meet the needs of vegetation at a particular time

Infiltration

The movement of water vertically through the pores in soil.

Integrated drainage basin management

Establishing a frame of coordinated efforts between administrations (e.g. local government) and stakeholders (e.g businesses) to achieve balanced management of a basin (World Bank)

Interception

Raindrops are prevented from falling directly onto the ground, instead hitting the leaves of a tree

Meteorological drought

When long-term precipitation trends are below average

Monsoon

The drastic variation between wet and dry seasons for sub-tropical areas, caused by a changed prevailing wind. Can lead to annual flooding.

Open system

A system affected by external flows and inputs (such as a drainage basin, or a sediment cell)

Percolation

Water moving vertically from soil into permeable rock

Physical water scarcity

A physical lack of available freshwater which cannot meet demand

relief precipitation

Precipitation caused when air masses are forced to rise over high land, determined by the relief/ morphology of the land

River regime

The pattern of river discharge over a year

Salinisation

Where salt water contaminates freshwater stores or soils, creating saline conditions and reducing human use/ consumption.

Saltwater encroachment

The movement of saltwater into freshwater aquifers or soils. This may be caused by sea level rise, storm surges or over-extraction

Smart irrigation

Providing crops with a water supply less than optimal, to make crops resistant to water shortages.

Storm hydrograph

Variation of river discharge over a short period of time (days)

Sublimation

the change of state of water from a solid to a gas without being a liquid

Throughflow

Water moving horizontally through the soil, due to gravity

Transpiration

The process through which water evaporates through the stomata in plants' leaves

Water budget

The annual balance between inputs and outputs within a system

Water conservation

Strategies to reduce water usage and demand

Water recycling

The treatment and purification of waste water, to increase supply

Water scarcity

There are limited renewable water sources (between 500 and 1000 cubic metres per capita per year)

Water security

The ability to protect and access a sustainable source to adequately meet demand

Water sharing treaty

International agreements for transboundary sources

Water transfer

Hard engineering projects, such as pipelines or aqueducts, that divert water between basins to meet demand

Watershed

the boundary between neighbouring drainage basins

Water insecurity

Prolonged period of water scarcity where the basic needs of the population aren’t met

Global water crisis

increasing worldwide water insecurity

Environmental impacts of water insecurity

sandstorms/wind blows topsoil away leading to desertification

fall in biodiversity , loss of habitat, soil degradation

Economic impacts of water insecurity

crop failure and livestock leads to loss of livelihood , removal of primary industry

Social impacts of water insecurity

crop failure and livestock death leads to hunger and malnutrition

drinking dirty water, more disease, reduced life expectancy

conflict over water resources, political instability

people flee/migrate, communities collapse

decline in quality of services eg schools

Social impacts of global water crisis

increasing conflict, regional instability

increase in epidemics and pandemics

mass migration

increased inequality

economic impacts of global water crisis

increasing cost of water resources

environmental impacts of global water crisis

regional/widespread desertification

How do shifting weather patterns as a result of climate change lead to increasing death rates due to disease

very low ppt

water scarcity

water shortages for drinking and washing

poor sanitation

increase in diseases eg typhoid, cholera

illness leaving people weak and unable to work

How does an increase in dust storms and wildfires lead to increasing deaths due to dehydration/malnutrition/disease

crops fail and livestock die

loss of farmers livelihoods

reduction in income

food shortages

rising food prices due to low supply

people unable to afford enough nutritionally appropriate food

extreme hunger

What are the 5 factors making up the water poverty index

Resources

Access to water

Handling capacity

Use of water

Environmental

What does ‘resources’ in the water poverty index involve

the quantity of surface and groundwater that is available per person, as well as its quality

What does ‘access’ in the water poverty index involve

the time and distance it takes in order for someone to access a sufficient and safe water supply

What does ‘handling capacity’ in the water poverty index involve

how well the community manages the water that is available

What does ‘use of water’ involve in the water poverty index

how the water is used domestically, industrially and agriculturally

What does ‘environment’ involve in the water poverty index

the ecological sustainability of the country, including management and regulation of water.

What is the water poverty index

The water poverty index shows how general poverty is linked to water poverty. The country’s index rating is scored on five factors each out of 20

What are the root causes of the impacts of water insecurity on women and girls

Poverty

Climate change

Rapid population growth

Poor governance

Poor infrastructure

Cultural norms

What are the social impacts of water insecurity on women and girls

gender inequality reinforcement

exposure to violence

lost employment opportunities

education disruption

mental and emotional stress

health risks - infections and disease

How does salinity occur

clearing of native vegetation

more water soaks into the soil

rising water table

salt stored naturally in the soil is lifted to the surface by the rising water table

salty water enters rivers

How does eutrophication occur

use of fertiliser on farms

fertilisers wash into waterways

nutrient rich water causes rapid algal growth

algae block sunlight and use oxygen

fish and aquatic plants die

Stores in the hydrological cycle

oceans , lakes and rivers, glaciers and ice caps , aquifers, groundwater, atmosphere (water vapour) , vegetation , soil moisture

Processes in the hydrological cycle

evaporation, condensation, sublimation, precipitation,freezing, transpiration, melting,desublimation

Flows in the hydrological cycle

channel flow , surface runoff, groundwater flow (through aquifers) , infiltration,percolation, throughflow (through soil), overland flow (only occurs when ground saturated), stem flow (water falling down stems/trunks), interception loss (water evaporates from plants before it hits the ground)

Residence times

how long water is in a store

impacts of water stress on forests

cavitation (drying out of trees’ water transport systems)

stomatal closure (photosynthesis)

pest outbreak

consequences of forest dieback

rapid carbon loss back into atmosphere

forests turn from carbon sink to carbon source

climate change eg increased drought expected to increase dieback

info gaps and scientific uncertainties limit future predictions

lag time

time delay between peak rainfall and peak discharge

Physical factors affecting hydrographs

vegetation cover- interception

location - levels of ppt

size of drainage basin

soil saturation

permeability of underlying geology/ rock type

soil type permeability

topography - steeper hills=faster runoff

drainage density (how many rivers are draining into the main channel)

Human factors affecting hydrographs

level of urbanisation - impermeable material

dams - slow water down

flood management strategies

drainage systems

deforestation

afforestation

Global water budget

oceans lose more water through evaporation than they gain through PPT. Opposite for landmasses.Surface runoff makes up the difference. If balance disturbed, oceans receive more water + continents dry.

fossil water

Ancient, deep groundwater made from pluvial (wetter) periods in the geological past eg in aquifers

annual flux

flows that enable the transfer of water in the hydrological cycle. Variations in flows due to temp, seasons and location.Flows eg evaporation greatest at equator , high PPT at equator

What does ENSO cause ?

Switch. Peru gets warm waters and Australia gets cold water. (usually this is the other way round). Can also trigger extremely dry conditions in SE Asia , E Aus, and NE Brazil. Can weaken monsoon in SE Asia.

Cyclonic precipitation

At the front (where two air masses meet), warm moist air is forced to rise above the cold air mass, causing the water moisture within to cool and condense forming cyclonic PPT. Depressions very common to UK.

Relief/orographic rainfall

When warm, moist air meets land of high relief (e.g. hills), the air mass is forced to rise above the hill to continue travelling. As it rises, the air mass cools and the moisture within condenses, to form clouds and rainfall.

Factors affecting infiltration

Soil Composition – Sandy soils have higher infiltration rates compared to clay. ▪ Previous precipitation - The saturation of soils. ▪ Type and amount of vegetation - interception of plants’ leaves will delay infiltration . ▪ Relief of land – sloped land will encourage more runoff

Factors affecting evaporation

Volume and surface area of the water body - the larger the surface area , the faster the rate of evaporation. ● Vegetation cover or built environment surrounding the water - anything that reduces direct sunlight to the water body will reduce evaporation. ● The colour of the surface beneath the water - black tarmac will absorb heat faster than white snow, and so evaporation will occur faster on the tarmac.

Water table

the upper level at which the pore spaces and fractures in the ground become saturated

River regime

A regime is the annual variation in discharge of a river at a particular location.

Factors affecting a river’s regime

Channel capacity of the river ▪ Area and relief of the drainage basin ▪ Volume, pattern and intensity of precipitation ▪ Climate ▪ Geology of the soil (affecting the input of groundwater) ▪ Anthropogenic (human) activities, such as building dams

Features of flashy storm hydrograph

short lag time

high peak

steep rising limb

intense storm/rapid snow melt

impermeable rocks

low infiltration rates

high and steep slopes

small basin

low density vegetation

basin already wet - soil saturated

high water table

urbanisation, deforestation

features of subdued storm hydrograph

long lag time

low peak

gently sloping rising limb

steady rainfall

slow snowmelt

permeable rocks

high infiltration rates

low and gentle slopes

large basin usually

high density basin

basin dry

low water table

soil not saturated

afforestation

Features of meteorological drought

rainfall deficit

low ppt

high temps

strong winds

increased solar radiation

reduced snow cover

• reduction in water available for consumption

Features of hydrological drought

stream flow deficit

reduced infiltration

low soil moisture

little percolation and groundwater recharge

• reduced storage in lakes and reservoirs

• threats to wetlands

Features of agricultural drought

soil moisture deficit

low evapotranspiration

reduced biomass

fall in groundwater level

• poor crop yield

• failing irrigation

Features of socio-economic drought

food deficit

loss of vegetation

increased wildfire risk

soil erosion

desertification

• food shortages

• rural economy collapses

• rural to urban migration

Value of wetlands

stores and flows of carbon

nutrient recycling

fuelwood

fisheries

reduced flood risk

water purification

aesthetic value

recreational use

What outputs of the hydrological cycle may climate change alter ?

less PPT

less water in stores

less snow/glacier mass

water table drops and aquifer stores deplete

high evaporation

more frequent cyclones and monsoons

solutions to water insecurity

many farmers store rainwater for irrigation and greywater purposes

mega dams

desalination

water transfer schemes

water treaties

Examples of sustainable water management

advanced more efficient irrigation systems

recycling city wastewater

GM crops

smart meters

restoration of wetland to increase water storage

4 parts of the integrated water resource management

groundwater management

waterway management

urban water management

monitoring technology

What is throughflow increased by ?

steeper slope angle

more porous soil

What is percolation increased by?

heavy rainfall , permeable soil and rock , vegetation

What is groundwater flow increased by?

gravity , permeable rock , water pressure

what is evapotranspiration increased by ?

high temp

vegetation cover

more solar radiation

what is interception increased by?

high veg cover

large leaf surface area

low wind speed