Management of River Environments (Edexcel IGCSE Geography): Flashcards
Exam code: 4GE1
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Define freshwater.
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Define freshwater.
Freshwater is water that is not salty, making up only 2.5% of all water on Earth.
Of all the freshwater on Earth, is stored in glaciers and ice sheets.
Of all the freshwater on Earth, 1.6% is stored in glaciers and ice sheets.
What percentage of global freshwater is accessible to humans in rivers, soil moisture, lakes, and the atmosphere?
Only 0.9% of global freshwater is accessible to humans in rivers, soil moisture, lakes, and the atmosphere.
True or False?
In developed countries, the majority of water is used for agriculture.
False.
In developed countries, most water is used for industry, not agriculture.
Define water balance.
The water balance is the difference between water supply and water demand.
A country has a when water demand is greater than water supply.
A country has a deficit when water demand is greater than water supply.
True or False?
Global water demand increased from 1 trillion m³ in 1934 to 4 trillion m³ in 2014.
True.
Global water demand increased from 1 trillion m³ in 1934 to 4 trillion m³ in 2014.
What are the three main sources of water supply?
The three main sources of water supply are lakes and rivers, aquifers and reservoirs.
Define water deficit.
A water deficit is a situation where water demand exceeds supply due to factors like low precipitation, high evaporation, or increasing population, industry or agriculture.
Areas with the greatest water deficit include , North, East and South Africa, Middle East, West USA, parts of South America, and .
Areas with the greatest water deficit include Australia, North, East and South Africa, Middle East, West USA, parts of South America, and India.
Define water stress.
Water stress occurs when the supply of water is below 1700m³ per person per year.
What conditions lead to a water surplus in some global regions?
A water surplus can occur where there is high supply (from high precipitation, low evaporation, or effective management) and/or low demand (due to low population, low temperatures, or effective water management).
Define potable water.
Potable water is clean water that is safe for human consumption, irrigation, and livestock use.
Diseases such as , , bilharzia and spread in polluted water.
Diseases such as typhoid, cholera, bilharzia and dysentery spread in polluted water.
What is eutrophication and how is it caused by agriculture?
Eutrophication is the process where nutrient pollution from agricultural fertilisers leads to excessive growth of algae, reducing oxygen levels in water and harming aquatic life.
True or False?
Industry can pollute water by releasing toxic substances and returning water at higher temperatures to rivers.
True.
Industries pollute water by discharging toxins from processes and by returning water used as a coolant at higher temperatures, which can harm aquatic life.
Define standpipe.
A shared water outlet used by many people in urban areas of developing and emerging countries where homes are not connected to a piped supply.
True or False?
In developed countries, over 90% of people have access to clean water due to better supply and storage infrastructure.
True.
Developed countries have more extensive and effective water supply and storage infrastructure, which enables over 90% of their population to access clean drinking water.
Dams are built across river channels to create a store of upstream.
Dams are built across river channels to create a store of water upstream.
What is the main reason desalination is mostly found in developed countries?
Desalination is mainly found in developed countries because it is an expensive process that uses a lot of energy, making it less accessible for developing countries.
Define desalination.
The removal of salt from seawater to produce clean water.
What is the purpose of a large-scale water transfer project?
To take water from areas of water surplus to areas of water deficit.
Which two processes are used to treat water at treatment works?
Filtration and disinfection.
Wells and ______ are used to access groundwater, which supplies almost 50% of the world's drinking water.
Wells and boreholes are used to access groundwater, which supplies almost 50% of the world's drinking water.
How does agriculture pollute water with fertilisers, herbicides and pesticides?
They dissolve in rainwater and enter the water system.
Define lag time.
The lag time is the period between the peak of rainfall and the peak discharge in a river, with a shorter lag time increasing the risk of flooding.
What human activities increase flood risk and why?
Human activities such as deforestation, urbanisation, and certain types of agriculture increase flood risk because they reduce interception and infiltration, leading to more overland flow and a shorter lag time.
Flooding usually occurs when the of the river channel is exceeded, causing water to flow onto the .
Flooding usually occurs when the capacity of the river channel is exceeded, causing water to flow onto the surrounding area.
True or False?
Steep slopes and impermeable rock types both increase flood risk by increasing overland flow.
True.
Both steep slopes and impermeable rock types reduce infiltration and increase overland flow, raising the risk of flooding.
Define soft engineering.
Soft engineering uses natural, sustainable solutions to manage flood risk and erosion.
Flood alerts are issued to inform people of current flood risk and the risk of flooding over the next days.
Flood alerts are issued to inform people of current flood risk and the risk of flooding over the next five days.
Define hard engineering.
Hard engineering involves building structures or changing the river channel to prevent or manage flooding.
True or False?
Soft engineering schemes aim to work with natural processes and minimise flood damage.
True.
Soft engineering works with the natural environment and is an example of mitigation, aiming to minimise rather than completely prevent flood damage.
Dams and reservoirs enable the amount of downstream to be controlled.
Dams and reservoirs enable the amount of discharge downstream to be controlled.
What is floodplain zoning and how does it reduce flood risk?
Floodplain zoning is a soft engineering method where only certain land uses are allowed on the floodplain, reducing the risk and impact of flooding by keeping vulnerable developments away from high-risk areas.
What is the main purpose of the Tagus-Segura Project in Spain?
The main purpose of the Tagus-Segura Project is to transfer water from the Tagus River to the south-east of Spain to reduce the water deficit and supply cities such as Alicante, Murcia, and Cartagena.
The South-North Water Transfer Project in China aims to transfer gallons of water a year from the south to the north to reduce .
The South-North Water Transfer Project in China aims to transfer 12 trillion gallons of water a year from the south to the north to reduce water insecurity.
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