4.2 WATER ACCESS, USE AND SECURITY
š Definitions Table
| Term | Definition (Exam-Ready, 2 Marks) |
|---|---|
| Reverse Osmosis | A water purification method that uses pressure to force water through a semipermeable membrane, removing salts and impurities. |
| Groundwater Recharge | The process where water from precipitation or surface sources infiltrates into the ground and refills aquifers. |
| Drip Irrigation | An efficient irrigation method that delivers water directly to plant roots through a network of tubes, minimizing evaporation losses. |
| Water Surplus | A situation where water supply exceeds demand in a particular area or time period. |
| Water Deficit | A condition where water demand exceeds available supply, often leading to stress on ecosystems or agriculture. |
| Water Scarcity | Long-term imbalance between water demand and availability, often due to overuse or drought, affecting sustainability. |
| Greywater | Wastewater from domestic activities like washing and bathing, which can be reused for irrigation after treatment. |
| Aquaponics | A sustainable farming system that combines aquaculture (fish farming) and hydroponics, using fish waste to fertilize plants. |
| Hydroponics | The method of growing plants in a nutrient-rich water solution without soil, often used in controlled environments. |
| Conservation Tillage | A farming practice that reduces soil disturbance, helping to retain moisture, reduce erosion, and improve soil health. |
- š§ Exam Tips:
Use sustainability language (e.g., conserve, efficient, reuse) for full marks on water management strategies.
Pair scarcity, surplus, and deficit with examples or causes if asked for explanation or evaluation.
š Factors Affecting Water Availability
- Water security is having access to sufficient amounts of safe drinking water
- Water security is essential for sustainable societies
- Without adequate water, societies cannot continue to exist
- Human well-being and health, agriculture and industries quickly begin to deteriorate when there is a lack of water
- Many different social, cultural, economic, political and geographical factors affect the availability of freshwater
- These factors also affect equitable access to this freshwater (i.e. how fairly this water access is distributed between societies)
Social factors
- Population growth:
- Larger populations increase water demand
- For example, Indiaās rapidly growing population is straining its water resources
- Larger populations increase water demand
- Population density:
- Regions with higher population densities tend to experience greater pressure on water resources
- Increased water demand for domestic, agricultural and industrial purposes can strain available supplies
- Urbanisation:
- Cities require very large amounts of water
- Living standards:
- Higher living standards often lead to higher water usage
- For example, developed countries like the USA use more water per capita than developing countries
- Higher living standards often lead to higher water usage
Cultural factors
- Water conservation:
- Cultures that prioritise water conservation tend to manage their water supplies better
- Some cultures may not prioritise water conservation, leading to wastage
- For example, in parts of the USA, despite ongoing droughts, water usage remains high due to a lack of conservation efforts
- Consumerism:
- High levels of consumerism often lead to increased water consumption
- For example, in Western countries, the high demand for consumer goods results in significant water usage for manufacturing and food production
- High levels of consumerism often lead to increased water consumption
- Traditional agriculture:
- Some traditional agricultural methods may use water inefficiently
- Cultural attitudes towards water pollution:
- Attitudes towards pollution can affect water quality
- In some regions, cultural indifference towards pollution has led to severe contamination of water bodies
Economic factors
- Economic development:
- Industrial activities require significant water resources
- Wealthier nations often have greater financial resources to invest in water infrastructure and management, which can result in better access to fresh water
- In contrast, poorer countries may lack the means to develop and maintain robust water systems
- Investment in infrastructure:
- The presence of well-developed water management systems, including reservoirs, dams, canals, and pipelines, can enhance water availability and distribution
- Investing in water treatment facilities ensures a better supply of safe drinking water
- Agricultural needs:
- Agriculture is a major water consumer
- For example, in Egypt, a large portion of water from the Nile River is used for irrigation
- Agriculture is a major water consumer
Political factors
- Government policies:
- Policies and regulations affect water distribution and quality
- For example, South Africaās National Water Act aims to ensure equitable water access and that the basic human needs of current and future generations are met
- Policies and regulations affect water distribution and quality
- International agreements:
- Transboundary water management requires cooperation between countries
- For example, the Nile Basin Initiative involves multiple countries working together to manage the Nile Riverās resources.
- Transboundary water management requires cooperation between countries
- Conflict and stability:
- Political instability and conflicts can disrupt water supplies
Geographical factors
- Geographic location:
- Some regions naturally contain abundant freshwater resources due to factors such as proximity to large rivers, lakes, or high rainfall
- Others, like arid and semi-arid regions, naturally have limited water availability
- Climate:
- Areas with high levels of precipitation, such as tropical rainforests or coastal regions, generally have better access to fresh water compared to arid or desert regions with low rainfall
- Topography:
- Mountainous regions often have better access to fresh water
- This is due to higher precipitation rates and the presence of glaciers and snowpack that act as natural reservoirs
- Conversely, flat or low-lying areas may face challenges in water availability
š TOK Tip: Who owns water? How do power structures influence access to natural resources?
š Strategies for Increasing Water Supply
- Human societies undergoing population growth or economic development need to increase the supply of water or use it more efficiently
- Water is essential for:
- Domestic use
- Agriculture (drinking-water for livestock and irrigation-water for crops)
- Industry
Strategies Used to Increase Fresh Water Supplies
| Strategy | Description | Example |
|---|---|---|
| Constructing dams and reservoirs | Structures built to store water, regulate flow and prevent floodsHelps store water during periods of high rainfall for use during dry seasons | The Hoover Dam in the USA creates Lake Mead, supplying water to several states and generating hydroelectric power |
| Rainwater Catchment Systems | Collecting and storing rainwater run-off from rooftops or other surfaces for domestic useCollected rainwater can be used for non-potable purposes like irrigation, toilet flushing and cleaning, reducing the strain on freshwater sources | In Chennai, India, rooftop rainwater harvesting helps tackle water scarcityIt also mitigates stormwater run-off, reducing flooding and erosion |
| Desalination Plants | Removing salt and minerals from seawater to produce freshwater using methods like reverse osmosis | The Jebel Ali Desalination Plant in Dubai provides a significant portion of the city’s water supply |
| Enhancement of Natural Wetlands | Improving wetlands to act as natural filters, removing pollutants and aiding groundwater recharge | The Everglades in Florida, USA, are being restored to enhance water flow and quality |
| Improving Irrigation Methods | Using efficient irrigation techniques like drip irrigation to reduce water wastage in agriculture | In Israel, the development and use of advanced drip irrigation technology has maximised water use efficiency |
| Water Recycling and Reuse | Treating wastewater for reuse in industrial processes or irrigation | Singapore’s NEWater project treats and reuses wastewater, reducing reliance on imported water |
| Artificial Recharge of Aquifers | Increasing groundwater supplies by directing surface water into the ground to replenish aquifersRecharging aquifers helps prevent groundwater depletion and maintains a sustainable supply of water for wells and springs | In California, USA, managed aquifer recharge projects help counteract over-extraction of groundwater |
| Redistribution | Efficient water redistribution systems, such as canals and pipelines, transfer water from water-rich regions to areas experiencing scarcityRedistributing water resources can help balance supply and demand, particularly in densely populated or arid regions | The Central Arizona Project in the USA redistributes water from the Colorado River to arid regions of Arizona |
Using a combined approach
- Sustainable management of freshwater resources requires a combination of strategies to enhance water supplies
- Dams, reservoirs, rainwater catchment systems, desalination plants and enhancement of natural wetlands are effective approaches to increase water availability
- However, these measures can be complemented by water conservation practices, recycling and reuse, recharging of aquifers and sustainable agriculture
- By adopting a comprehensive and balanced approach, societies can ensure the sustainable use of freshwater resources
š Addressing Water Scarcity
- Water is unevenly distributed around the globe
- There are significant areas of water surplus and water deficit
- Around 450 million people in LICs suffer from severe water shortages
- Around 1.2 billion live in areas of water scarcity
- Physical water scarcity occurs where demand for water outstrips supply, often due to arid climate and low rainfall
- EconomicĀ water scarcityĀ is where water isĀ availableĀ but peopleĀ canāt affordĀ it or theĀ infrastructureĀ isĀ inadequate
Domestic Water Conservation Techniques
| Technique | Description |
|---|---|
| Metering | Install water metres to monitor and control water usage accuratelyIt helps households track their consumption |
| Rationing | Set limits on water usage per householdThis can involve implementing quotas or tariffs based on usage levels |
| Grey-water Recycling | Capture and treat greywater for reuse in non-potable applications like toilet flushing or outdoor irrigation |
| Low-flush Toilets | Install toilets with low-flow mechanisms to reduce water usage per flush |
| Rainwater Harvesting | Collect and store rainwater for tasks such as watering gardens or washing vehicles. |
Industrial Water Conservation Techniques (Food Production Systems)
| Technique | Description |
|---|---|
| Greenhouses | Use greenhouses equipped with large-scale rainwater harvesting systems to irrigate the crops grown inside) |
| Aquaponics Systems | Integrated aquaponics systems combine fish farming with hydroponic plant cultivationThese closed-loop systems recycle water between fish tanks and plant beds, reducing overall water consumption |
| Drip Irrigation | Install agricultural drip irrigation systems to deliver water directly to the roots of crop plants, minimising evaporation and surface run-off |
| Drought-resistant Crops | Develop and cultivate crops that are resilient to drought conditionsThese crops require less water to grow and are suited for arid regions |
| Switching to Vegetarian Food Production | Transition to plant-based agriculture to reduce the significant water usage associated with livestock farming |
Case Study
Mitigation Strategies for Water Scarcity
Country Case Study: Australia
- Some parts of Australia face water scarcity challenges due to the arid climate and variable rainfall
- To address these issues, the country has implemented a range of innovative water management strategies, including:
- Water pricing mechanisms
- Tiered water pricing: Australia uses a tiered pricing structure where the cost of water increases with higher usage levels
- This approach incentivises households and businesses to conserve water
- Water trading: in regions like the Murray-Darling Basin, water trading allows users to buy and sell water allocations
- This market-based approach helps allocate water more efficiently, especially during drought periods
- Tiered water pricing: Australia uses a tiered pricing structure where the cost of water increases with higher usage levels
- Desalination plants
- Sydney Desalination Plant: Sydney’s only major source of non-rainfall dependent drinking water
- This plant can supply up to 15% of Sydney’s drinking water, providing a reliable water source during droughts
- It uses reverse osmosis to remove salt and impurities from seawater, ensuring a continuous supply of fresh water
- Perth Desalination Plant: one of the largest desalination plants in the Southern Hemisphere
- It meets about half of Perth’s water needs
- This demonstrates the effectiveness of desalination in supplementing traditional water sources
- Sydney Desalination Plant: Sydney’s only major source of non-rainfall dependent drinking water
- Water recycling programmes
- Purple pipe systems: in some cities, recycled water is delivered through a separate “purple pipe” system for non-potable uses
- This includes irrigation, industrial processes and toilet flushing
- This reduces the demand on potable water supplies
- Western Corridor Recycled Water Scheme: this project in Queensland treats and purifies wastewater to a standard suitable for industrial use
- In times of need, it can also supplement drinking water supplies
- Purple pipe systems: in some cities, recycled water is delivered through a separate “purple pipe” system for non-potable uses
- Crop selection and rotation
- Drought-resistant crops: farmers are encouraged to grow crops like sorghum and millet
- These require less water and are more resilient to dry conditions
- Research institutions, such as the Commonwealth Scientific and Industrial Research Organisation (CSIRO), are developing new varieties of drought-tolerant crops
- Sustainable farming practices: using crop rotation and conservation tillage helps maintain soil moisture and reduce water usage
- For example, rotating legumes with cereals can improve soil fertility and reduce the amount of irrigation required
- Drought-resistant crops: farmers are encouraged to grow crops like sorghum and millet
- Community awareness and education
- Water conservation campaigns: public awareness campaigns, such as “Target 155” in Victoria, encourage residents to limit their water use to 155 litres per person per day
- These campaigns educate the public on water-saving techniques and the importance of water conservation
- School education programmes: schools incorporate water conservation into their curricula, teaching students about sustainable water use and the importance of preserving this vital resource
- Water conservation campaigns: public awareness campaigns, such as “Target 155” in Victoria, encourage residents to limit their water use to 155 litres per person per day
- These strategies illustrate Australia’s comprehensive approach to managing water scarcity through a combination of technological innovation, economic incentives and public education