Freshwater - water scarcity and quality Flashcards
Define physical water scarcity
When the natural supply of freshwater is insufficient to meet the demand
Define economic water scarcity
When the supply of clean and affordable freshwater fails to meet demand as a result of underdevelopment, lack of infrastructure or polluting economic activities
What are the patterns of water scarcity globally?
- Large parts of South and Central Asia as well as North Africa suffer physical water scarcity
- Large parts of Sub-Saharan Africa, northern India, and regions within Peru and Bolivia suffer economic water scarcity
Give examples of when physical water scarcity can occur
- When populated regions suffer droughts
- When water is temporarily polluted by natural events such as tidal surges and tsunamis
It is mainly …. …. climates that see regular droughts characterize their climate sufficient enough to create …. water scarcity. Fill in the gaps.
- Tropical Wet-Dry
- physical
Where is the Sahel region?
In Sub-Saharan Africa
What is the Tropical Dry season of the Sahel region created by?
Global atmospheric circulation
With references to the Tricellular model, explain how the Sahel has a Tropical Dry/Wet climate
The relative position of the sun affects atmospheric circulation. When the sun is highest in the sky in an area called the Inter-Tropical Convergent Zone, low pressure is created and rain falls. When the sun moves away, slow sinking air that forms high pressure zones warm and relative humidity falls. This locks moisture in, creating dry conditions. This is why droughts are common place in the Sahel.
Where is high pressure experienced? (global atmospheric circulation)
At latitudes of 30 degrees and at the poles
With climate change, droughts seems to be increasing in both …. and …. . Fill in the gaps.
- frequency
- extremity
Why does El Nino take place?
Due to changes in ocean currents in the Pacific Ocean
What does El Nino lead to?
High pressure zones in South East Asia due to slow sinking air, creating drier conditions in the normal wet climate of South East Asia.
Why are droughts more frequent in South East Asia now?
Droughts already existed due to El Nino. However, they have become more frequent because climate change has made El Nino more frequent
How can continentality cause droughts?
Air movement over large land masses such as Australia becomes moderated by the dry conditions of the land. Being a large distance away from large bodies of water means the air is dry and little rain forms.
How do droughts impact HICs?
They disrupt society leading to water rationing and restrictions. Often countries will restrict the use of water for example banning its use in gardens and private pools. However, droughts especially in Europe tend not to be too severe or prolonged.
How do droughts impact LICs?
They can directly impact water and food security. Crop failure occurs and in countries where many millions are subsistence farmers or spend a disproportional amount of their income on food, droughts can lead to hunger, displacement, food aid dependency and at worst famine.
How can physical water scarcity impact economic output and energy security?
With insufficient water, industry is less productive and without secure energy supplies, market confidence is damaged, private investment is limited and economic output is held back
Many …. regions suffer economic water scarcity. Fill in the gap.
- underdeveloped
According to the WHO and UNICEF, how many people did not have access to basic water services in 2017?
More than 785 million
According to the WHO and UNICEF, how many people did not have safe water to drink in 2017?
More than 884 million
Outline the context in which economic water scarcity occurs as a result of under-development and a lack of infrastructure
In this context water is naturally abundant, with only 25% of freshwater extracted from rivers and lakes for human use. This context is predominantly a rural context whereby people are forced to walk to nearby rivers and ponds each day to collect their daily needs. The government lack the human capacity, skills, institutions and finance to supply clean water to people.
Outline the context in which economic water scarcity occurs as a result of polluting economic activities
In this context people face the problem of polluted water that is the result of drainage basin mismanagement. There are many causes of this including domestic waste and industrial and agricultural effluence that contaminate water systems, rivers, lakes and aquifers. This context exists in all countries but is most significant in emerging economies where there is little investment in water services and limited enforcement of government regulations. A great example of economic water scarcity is in China whereby it was brought about by the rapid growth of unregulated economic activity.
Define eutrophication
The process of increasing concentrations of nitrogen and phosphorus in freshwater environments, leading to algae growth and loss of oxygen
Define salinization
The increasing concentration of salt in soils as a result of land mismanagement and over-irrigation
Define stakeholders
Interest groups that have a direct or indirect role
Industrial farming systems tend to adopt an intensive …. approach that prioritizes increased …. and limits …. . Fill in the gaps
- monoculture
- yields
- biomass
What is a monoculture?
Farming one plant or animal
Monocultures are prone to …. . Fill in the gap
- disease
How do industrial farming systems reduce the risk of disease?
By having an intense use of pesticides
What are the negative consequences of chemical fertilizers and ploughing?
They reduce soil structure and health and increase the dependency on fertilizers
…. crop rotation takes place in industrial farming systems. Fill in the gap
- Limited
How have industrial farm systems brought about unused or infertile soils into production?
Through intensive use of pesticides, fertilizer and water inputs
How do organic farming systems contrast with industrial farming systems?
Organic farming systems use only natural fertilizers and reduce the need for pesticides through careful crop rotation and mixed cropping as well as encouraging additional biomass.
State the environmental consequences of agricultural activities on water quality
- River sedimentation
- Eutrophication
- Salinization
What is the consequence of deteriorating soil health?
It becomes more prone to wind and water erosion
Cropland agriculture is considered the biggest driver of …. …. and is expected to increase with …. …. and …. …. . Fill in the gaps
- soil erosion
- population growth
- climate change
According to the GloSEM platform, which regions are most at risk of soil erosion?
Sub-Saharan Africa, South America and Southeast Asia
Why is river sedimentation a bad thing for water systems?
It reduces water quality by reducing the amount of sunlight reaching living organisms in the water. This results in the loss and decomposition of aquatic life, which in turn reduces the nutrient content of water systems.
What does intensive use of chemical fertilizers and pesticides on croplands cause?
It causes nitrogen and phosphorus to leach through the soil and enter groundwater aquifers, river and lakes.
Outline the positive feedback loop that is eutrophication
The elevated concentrations of nitrogen and phosphorous in freshwater leads to accelerated growth of algae blooms. These blooms block sunlight impacting the health of aquatic life such as river grasses and fish. The death of the aquatic life and later decomposition reduces oxygen levels in the water. As algae dies and decomposes more oxygen is lost which accelerates the loss of aquatic life further in a positive feedback loop.
What are two great examples of eutrophication at large scales?
Eutrophication in Lake Erie, USA, and the Dead Zones in the Baltic Sea
…. …. environments are most susceptible to salinization. Fill in the gaps
- Dry climate
Why are saline levels in soils closely linked with patters of vegetation?
Because patters of vegetation influence patterns of rainfall, water table levels and salt levels
In what two ways does agriculture accelerate salinization?
- The removal of indigenous vegetation
- Poor farming and irrigation methods
How does the removal of indigenous vegetation accelerate salinization?
Indigenous vegetation in salt-prone soils is naturally salt resilient and has specially adapted to repel salt and secrete salt. Dense vegetation in dry regions also carefully regulates rainfall and water tables reducing the levels of salt in soils. The removal of this vegetation for farmland interferes with these processes and more shallow roots allow the water table to rise. This brings natural salts closer to the surface.
Where does saline seepage occur?
Where the water table intercepts the ground surface
How do poor farming and irrigation methods accelerate salinization?
Over-irrigation can lead to increased salt deposits in the soil layer. All water contains natural salts. As excess water is evaporated it leaves salt behind. Evaporation of soil moisture also draws up more saline water from below in a process called capillary rise. Farmers who fail to measure and administer the right amounts of water to their fields increase salinization.
What is precision farming?
It involves the use of GPS systems, drones and computer systems to target water, chemical fertilizer and pesticide use where they are most needed.
Why do farmers have an important role to play in safeguarding the environment from the negative consequences of agricultural activities?
Because they are considered stewards of the landscape and through careful management can make a big impact in reducing environmental impacts.
What are the benefits of precision farming?
Farmers can reduce water, chemical fertilizer and pesticide use in their fields. In doing so, they reduce excessive use of inputs, reducing costs, increasing yields and improving the environment by helping prevent leaching in soils and freshwater systems.
What is an example of a technology that can help farmers farm precisely?
Pivot and drip feed irrigation systems that administer the appropriate amount of water, fertilizer and pesticide to their fields. However many of these technologies require significant investment by farmers.
Outline softer environmental approaches taken by farmers across the EU to improve the environment
Farmers across the EU can receive government support for increasing forest cover and natural berms in their land. Forests and berms improve biodiversity, provide for nature corridors and also help proved environmental services such as water storage.
Why can the mismanagement of land and water in one location have wider impacts on communities and stakeholders downstream?
Because river systems are integrated and cross many political districts and stakeholders, including rural areas, farmers, businesses and cities
Integrated drainage basin approaches are often government-led but integrate all stakeholders, including …., …., …. and …. . Fill in the gaps
- farmers
- land owners
- households
- businesses
What is the benefit of creating committees to coordinate drainage basin approaches?
Through committees, best practices can be shared and policy agreements can be made that coordinate water use in the area.
Outline the Thames Water Integrated drainage basin approach in the UK
They have worked alongside universities, farmers and voluntary agencies to help improve water quality. For example, they worked with farmers to evaluate the benefits of cover crops on nitrate levels in the soil. Results from the trials showed that nitrate losses were significantly reduced, with mean concentrations between five and ten times lower with the presence of a cover crop compared to a bare soil control plot.
Who are Thames Water?
They are a company responsible for the supply of clean water to Thames communities
What are swales?
Shallow ditches created to slow run-off from fields
What are cover crops?
They are non-cash crops grown to protect the soil from erosion, improve soil health and minimise losses of nutrients through leaching and runoff
Define drainage zone
The catchment area where surface water flows
Define recharge zone
An area of permeable/porous rock that allows water to percolate through it
Define Artesian Zone
The area where water under hydrologic pressure rises back to the surface either through wells or springs
Define Recharge
The rate at which water enters the aquifer
Define Abstraction
Water being taken out of the aquifer
Define point-source pollution
A specific event or source that contaminates the aquifer
Define non-point source pollution
Contamination of the aquifer that comes from different sources
Water enters the aquifer via …. rock in an area known as the …. …. . Fill in the gaps
- porous
- recharge zone
Water within an aquifer can rise upwards if the rocks above it is …. or it may remain trapped in a confined aquifer if the rock above and below it is …. . Fill in the gaps
- porous
- impermeable
Layers of different rock strata will therefore determine the nature of the aquifer, either confining it or allowing it to rise through …. …. . Fill in the gaps
- hydrologic pressure
Which human activities are most responsible for polluting surface water and subsequently
