the water cycle Flashcards
what human factors can affect hydrograph shape?
- urbanisation
- agriculture/farmland
- channelisation
- dams/ hard engineering
- deforestation
- aforestation
how can agriculture/farming affect hydrograph shape?
- farm machinery can compact soil so its impermeable resulting in a flash hydrograph
- after harvest = flash
- before harvest = flat
what physical factors can affect hydrograph shape?
- number of tributaries
- relief
- vegetation cover
- geology
- rainfall amount
- size + shape of catchment area
when may there be a flash hydrograph?
- thunderstorms
- urban areas
when may there be a flat hydrograph?
- forest areas
- chalk area
how is rain formed ?
- air rises
- air cools
- condensation
- rain falls
when will there be relief rain?
when a mountain causes the air to rise, resulting in rainfall
when will there be frontal rain?
when warm air meets cold dense air
when will there be convectional rain?
when hot temperatures cause the air to rise
why is the global hydrological cycle a closed system?
the amount of water within the system stays the same, it is transferred between different stores
what are examples of stores in the drainage basin system?
- groundwater
- vegetation
- soil
what are examples of outputs in the drainage basin system?
- river flow into the sea
- evaporation
- evapotranspiration
what is an example of inputs into the drainage basin system?
- precipitation
what are examples of flows in the drainage basin system?
- infiltration
- percolation
- surface run-off
- through flow
- groundwater flow
define afforestation
planting trees on land that has never had a forest
define agricultural drought
a rainfall deficiency from meteorological drought leading to deficiency in soil moisture, affecting plant growth and yields.
define aquifers
a permeable or porous rock which stores water
define base flow
the normal day-to-day discharge of a river
define blue water
water stored in rivers, streams, lakes and groundwater in liquid form
define catchment area
the area of land drained by a river and its tributaries
- drainage basin
Define closed system
A sequence of linked processes with a transfer of energy, but not matter, between the parts of the system
Define condensation.
The change from a gas to a liquid?
Define cryosphere
areas of the earth where water was frozen into snow ice.
Define deforestation.
The cutting down removal of all or most trees in a forested area.
define desalination.
The process of converting salt water to fresh water suitable for human consumption and industry.
Define desertification.
Land degradation in arid, semi arid and dry, subhumid areas resulting from various factors including climatic variations and human activities.
Define dew point.
The temperature at which Dew forms.
Define drought.
An extended period of deficient rainfall relative to the statistical outrage for a region measured over a very long period of time.
Define economic waters scarcity.
when water resources are available, but there is insufficient human institutional and financial capital to access the water in order to meet demand.
Define eutrophication.
Excessive richness of nutrients in a lake or other body of water frequently. due to runoff from farming land, which causes a dense growth of plant life and death of animal life from a lack of oxygen.
Define evaporation.
The change in the state of water from a liquid to a gas.
Define Evapotranspiration.
The combined effect of evaporation and transpiration.
Define falling limb.
The pot of a storm hydrograph in which the discharge starts to decrease and returns base flow.
Define famine drought.
A humanitarian crisis in which the widespread failure of agricultural systems needs to food shortages and famines with several social, economic and environmental impacts.
Define flash flood.
A flood with an exceptionally short lag time, often minutes or hours.
Define fossil water.
Ancient deep groundwater from former wetter periods.
Define green water.
Water stored in the soil and vegetation.
Define groundwater flow.
The slow transfer of percolated water underground through porous rock.
Define hard engineering
The use of man-made artificial structures to manage flooding or water supply.
Define hydrological drought.
Associated with reduced stream flow and groundwater levels, which decreases because of reduced inputs of precipitation and continued high rates of evaporation, regarding reduced storage in lakes and reservoirs.
Define infiltration.
The movement of water from the ground surface into the soil.
Define intertropical convergence zone.
A concentration of warm air that produces rainfall as part of a global circulation system. It moves N and S across the equator seasonally. Small shifts and location can cause drought.
Define meteorological drought.
Defined by shortfalls and precipitation as a result of short term variability or longer term trends, which decrease the duration of the drive.
Define Monsoon
A seasonal change in the direction of prevailing winds of a region causing wet and dry seasons in many subtropical areas.
Define peak discharge.
, the time when the river reaches its highest flow.
Define percolation
The transfer of water from the surface or from the soil into the bedrock beneath.
Define potential evaporation.
The water lost that would occur if there was no limited supply of water in the soil for use by vegetation.
Define precipitation.
The movement of water in any forms from the atmosphere to the ground.
Define residence time.
The average time a water molecule will spend in a reservoir or store
Define rising limb
The part of the storm hydrograph in which the discharge starts to a rise.
Define River regime.
The annual variation in discharge or flow of the river at a particular point or gauging station, usually measured in tumax.
Define saltwater encroachment.
The movement assault water into fractured water aquifers due to sea level rise, Storm surges and/ or human abstraction of groundwater, which lowers the water table.
Define stores.
Reservoirs by water held such as the oceans.
Define storm hydrograph.
Shows changes in a rivers discharge at a given point on a river over a short period of time.
Define surface runoff.
The movement of water that is unconfined by a channel across the surface of the ground, also known as overland flow.
Define surface water flooding.
Flooding that occurs when intense rainfall has insufficient time to infiltrate the soil, so flows over land.
Define thermohaline circulation.
The global system of surface and deep water ocean currents is driven by temperature and salinity differences between areas of oceans.
Define through fall.
This is when the rainfall possess or is relatively intense, and the water drops from the leaves twigs, needles, etc.
Define through flow
Water moving sideways through the soil downslope under the influence of gravity.
Define transboundary water.
A water resource including rivers lakes and aquifised occupies a territory shared by more than one state.
Define transpiration.
The diffusion of water from vegetation into the atmosphere involving a change from a gas to a liquid.
Define treaty.
An agreement signed between states recognised and international law.
Define water budget.
The annual balance between inputs and Outputs at a place.
Define water conservation.
Strategies to reduce water usage and demand.
Define water insecurity.
Occurs when the economic, social and environmental requirements for water supplies are not met.
Define water recycling.
The treatment and purification of waste water using advanced membrane technologies and UV disinfection so that it is cleaned and safe to be reused for industrial or domestic purposes.
Define water scarcity.
Occurs when renewable water resources are only between 500 and 1000 metre cubed per capita per year.
Define water security.
The capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well being and socio economic development for ensuring. protection against waterborne pollution and water related disasters and for preserving ecosystems in a climate of peace and political stability.
Define water stress.
When renewable water resources are only between 1000 and 1700 metres cubed per capita per year.
Define water transport.
Hard engineering portraits such as pipelines or aqueducts that divert water from drainage basins with surplus water to those shortages.
Define wetland.
An area of marsh, fen, peatland or water, where the natural artificial, permanent or temporary, with what of it is static or flowing fresh, brackish or salt.
Define watershed.
The Highland, which divides and separates waters flowing into different rivers.
What are features of a depression?
- low air pressure
- cloud between fronts
- isobars closer together so strong winds
- mild weather throughout the year
- anticlockwise wind direction.
What features of anticyclones?
- High air pressure
- clear skies
- isobars further apart so light winds or calm
- in the winter it’s very cold with frost at night
- in the summer It’s very hot during the day and cooler at night
- clockwise wind direction.
what are the 2 fronts on a weather map.
- cold front –> heavy rain
- warm front –> drizzle
what does ITCZ stand for?
inter-tropical convergence zone
what is the ITCZ?
Where the trade winds meet at the equator creating rising air, low pressure and heavy rain. The position of the ITCZ will affect the amount of rainfall a country gets
what are the 3 air cells in the global air circulation model?
- Polar cell
- Ferrel cell
- Hadley cell
what does high air pressure cause?
dry, little/no rain
what does low air pressure cause?
heavy rain
what happens when 2 hadley cells meet?
- low air pressure
- heavy rain
what happens when 2 polar cells meet?
- high air pressure
- dry
what happens when the polar and ferrel cells meet?
- low air pressure
- heavy rain
what happens when the hadley and ferrel cells meet?
- high air pressure
- dry
What is a river regime?
The annual pattern of flow or discharge.
How many river regimes differ?
Tropical river will have a more uniform regime as rainfalls every month. However, most rippers will have a seasonal regime as they respond directly to the amount of precipitation.
what are the two types of river regimes?
- Simple, where rivers experience a period of seasonally high discharge, followed by low discharge such as in the temperate climate.
- complex where larger rivers cross several different relief and climatic zones, so experience different climatic events
What factors may affect river regimes
- Dams
- climate
- geology
- soils
- land use.
How many dams affect river regimes?
Dams mean that water can be held back or released. This would result in a more constant and uniform regime.
How can climate affect river regimes?
The amount of intensity of rainfall will affect a regime alongside the temperature due to changing rates of evaporation and snow or glacial melt.
How can land use effect with regimes
Urban areas will have more impermeable land surfaces, which increases runoff, so there will be a higher regime, whereas farming areas may have a more varied regime as it would be lower on crops are growing, but higher after harvest. Forested areas were to have a lower regime, as there would be more infiltration.
How can geology affect river regimes
- impermeable = higher regime
- permeable = lower regime
How can soils affect river regimes?
More saturated soil would have a higher regime, and so would a dry compact soil. The permeability of the soil would also affect the regime alongside the depth.
What are antecedent conditions?
The previous weather conditions.
What factors may result in a flashy hydrograph?
- intense weather events
- impermeable rocks or soil
- steep slopes
- small, circular basins
- high drainage density so more streams and rivers
- low density vegetation
- urbanisaiton
What fact has may result in a flat hydrograph?
- steady rainfall
- permeable rock or soil
- gentle slopes
- larger, elongated basins
- low drainage density so few rivers
- dense deciduous woodland
- dry basin
- low population density
Describe the distribution of populations without access to safe water.
North America Oceana and Northern Europe have 0-6% of the population without access to safe water. Whereas Africa, with the most variation, has Botswana and Egypt with 0-6% without, but Chad and Ethiopia have 64-87%. The majority of countries in Africa have 33-63% of the population without access to safe water.
What are five examples of bottom up strategies for water management run by water aid?
- pumpkin tank
- composting toilets
- water/rope pump
- education on hygiene
- diguettes
What is the pumpkin tank and how is it sustainable?
The pumpkin tank collects grey water off of the roof and stores it, helping to deal with seasonal rain and poor quality drinking water.
- children don’t have to walk miles to collect water, so can go to school
- remain healthier, meaning they live longer
- adults can be more productive when working
- low cost scheme
- uses local resources.
What are composting toilets and how are they sustainable?
They are pits in private toilet blocks that create compost, which can be used on crops to increase yields. This prevents contamination of water supply, resulting in cleaner water as the people remain healthier, reducing the spread of diarrhoea.
What are water and rope pumps and how are they sustainable
Water pumps are used to extract groundwater whilst rope pumps collect water in the rope. This means that children don’t have to walk far to get water so they can spend more time in school and also provides a clean source of water.
What is the water cycle of poverty?
Children’s they’re in a dirty water and get sick. This means families pay health care costs and for deepened poverty. The village then spreads for disease in The Dirty water due to poor sanitation. So young girls have to continue to walk to collect waters. They miss out on school.
Where is water scarcity?
a lack of potable (drinking) water
Why is the water poverty index?
An index used to measure the levels of water insecurity. It looks at water resources and the access to safe water alongside the effectiveness of water management, the use of water and. environmental strategies to ensure ecological sustainability.
What countries tend to have a high water poverty index score?
High income countries.
What are some physical and human reasons for the water poverty index variations?
- rock type
- geographical location -> climate, rainfall
- population size
- industries
- contaminated water
- proportion of urban areas
- varying investement in clean water supplies
What are diguettes?
Stone walls placed around contour lines which reduce the flow of water and trap sediment, preventing soil erosion and allows for the infiltration of water. This has increased yields. and allowed for the reclamation of land from desertification.
Where is the Aral Sea located?
between Uzbekistan and Kazakhstan
what is over abstraction?
taking too much water out of a lake/river/aquifer
why was the Aral Sea over abstracted?
- Soviet government wanted to to irrigate the desert to allow cotton crops to grow, the canals for this were leaky
- larger population putting pressure on resources
what are social impacts of the Aral Sea disaster?
- illness such as cancer due to pollution
- widespread poverty
- increased infant mortality rates
what are economic impacts of the Aral Sea disaster?
- loss of tourism and income
- fishing and canning industries closed
- mass migration away from the area
what are environmental impacts of the Aral Sea disaster?
- fish have disappeared
- air pollution of agrochemicals
- Aral sea has shrunk
what was the response to the Aral Sea Disaster?
- a dam was built between the North and south of the sea, allowing the north to increase in volume
- saxaul trees planted to trap sediment
what are environmental impacts of the 3 gorges dam?
- siltation of the reservoir
- farmland submerged
- trapped sewage/rubbish
- extinction of river dolphin
- dam could break and cause flooding
- landslides
what are economic impacts of the 3 gorges dam?
+ HEP generated allowing economic growth
+ safer navigation for shipping
- high cost
what are social impacts of the 3 gorges dam?
- 1.3 million people relocated
- cultural heritage sites submerged
- compensation not received due to corruption
+ new settlements will have improved housing/sanitation
+ provide jobs
How was the Aral sea irrigated?
the 2 rivers that feed into the Aral sea were diverted
why was the 3 gorges dam built?
- reduce flood risk
- irrigation
- HEP
- better navigation by boat
where was the 3 gorges dam built?
along the Yangtze river in China
what is The South North River Transfer Project
3 diversion routes along the Yangtze river to transport water from the humid south to the arid north
what are the advantages of The South North River Transfer Project
- Reduce the abstraction of groundwater.
- Reduce water insecurity in Beijing, boosting economic development.
- Improved food security as there is more irrigation for farming.
- Improved water quality will improve health.
what are the disadvantages of The South North River Transfer Project
- High cost
- 370km2 of land will be submerged.
- 345,000 people will have to relocate.
- Risks draining too much water from Southern China.
- Risks of further pollution as the Eastern Route is industrial.
- Ecological damage to the natural environment.
- The region is prone to earthquakes which could damage the infrastructure.
why is there high water demand in the north of China?
large cities including Beijing, means the north has a high population density
Why can hard engineering sometimes cause more flooding?
- dams require land to be flooded to form a resevoir
- the levee in New Orleans breached which flooded the city after Hurricane Katrina
- rerouting of the river Rhine meant it was 100km shorter and travels 30% faster
When were the Boscastle floods
2004
What were the causes of the Boscastle floods
- low lying land
- village built on the floodplain
- very heavy rain
- ground was already saturated
- impermeable slate and clay
Boscastle is at the confluence of which two rivers.
- river valency
- river jordan
What were the causes of the 1995 European floods?
- abnormally high rainfall
- high spring temperatures leading to snowmelt
- deforestation
- urbanisation
- farming
- rerouting of the river Rhine.
What were the effects of the 1995 European floods?
- 250,000 evacuated
- homes in Holland and Germany flooded
- sports halls used as evacuation centres
- dykes were broken to allow water to flow through them
- Animals evacuated.
What were the solutions to the 1995 European floods?
- Floodproofing houses
- Dams and reservoirs were built to regulate river flow.
- Flood retention basins.
- Building dykes which act as walls or embankments to hold rising water levels.
- Making the course of the rivers straighter and shorter.
- Afforestation.
- Floodplain land use zoning.
What are example of hard engineering strategies for flood management?
- flood wall or embankment
- levees
- dredging
- rerouting
- dams.
What are examples of soft engineering strategies for flood management?
- Tree planting
- flood water pumping
- sandbags
- floodplain zoning.
What are the advantages of dams?
They control the release of water. and can provide hydroelectric power.
Whatever disadvantages of a dam.
- expensive
- settlements/
agricultural land will be lost in order to build the reservoir. - Sediment will be trapped behind the dam, which can lead to a erosion further downstream and lower fertility of soil.
What are advantages of building a flood wall?
- Protect buildings in the surrounding area
- Occupants don’t have to leave the settlement during construction.
Whatever disadvantages of building a floodwall
- unnatural and unattractive
-expensive - can be breached
What are the advantages of levees.
They look more natural, are effective and protect the land around the river.
What are disadvantages of levees?
They’re expensive and can still be breached.
What are the advantages of dredging?
Allows more water to be held in the channel and. which reduces the flood risk in built up areas
what are the disadvantages of dredging.
It is expensive and needs to be done regularly. Removing the natural silt can lead to fewer nutrients in the soil.
What are the advantages of tree planting
It is a sustainable and relatively cheap option.
What are the disadvantages of tree planting
The trees take time to grow, and lots must be planted for it to be effective.
What would be advantage of rerouting rivers
Straightening of River Channel will increase the speed at which flood water flows.
What are the disadvantages of rerouting rivers
Changes for natural flow of the river, leading to potential further problems downstream.
Were the advantages of floodplains
It uses for land effectively to place high value. Buildings further from the flood zone.
What were the disadvantages of floodplain zoning?
It is only useful for new developments as some settlements have been built over hundreds of years. So it’s difficult to move them.
What are the advantages of sandbags?
They are cheap and effective on a small scale. and can provide quick and easy flood protection
What are the disadvantages of sandbags?
They only protect against small floods.
what weather does El Nino control?
- rainfall
- temperatures
what happens in a normal year?
There are consistent trade winds that push water from the East to the West of the Pacific ocean.
There warm water and increase rainfall in Australia and Asia ( West ) and cold water in South America ( East )
what happens during an El Nino year?
The trade winds switch so warm water is pushed to the East. This leads to colder waters, drought and high air pressure in Australia and warmer water with more rainfall in South America.
what are some impacts of El Nino?
- depleted fishing stocks in Peru
- damaged crops and food insecurity in Central America
- flooding, torrential rain, mudslides in South America
- increase in cyclones
- severe drought in East Africa and food insecurity
- poor harvests, prolonged dry season and forest fires in Asia and Australia
what is El Nino?
- a natural phenomenon that occurs every 3-7 years and leads to weather catastrophes in the East and West Pacific
