Addressing Water Stress (HL) (DP IB Environmental Systems & Societies (ESS))

Industrial Level Strategies

• At an industrial level, various strategies can be used to manage water stress

  • These strategies ensure more sustainable water use and management

• Large-scale infrastructure and technological solutions are often used to address water stress

  • These solutions improving access to water for agriculture, industry, and communities

  • Each of these approaches has its specific applications, benefits, and challenges

Dams

• Dams are large structures built across rivers to block or slow water flow, creating reservoirs that store water for future use

• Advantages:

  • Store large volumes of water for long-term use in agriculture, irrigation, drinking, and industry

  • Water can be released in controlled amounts

  • Provide hydroelectric power and flood control

• Limitations:

  • Floods ecosystems upstream of dam

  • Can displace human communities

  • Disrupts natural river flow, affecting fish migration and sediment transport

Water transfer

• Water transfer involves moving water from areas with surplus supply to regions with shortages, typically through canals or pipelines

• It is often used to balance regional water availability for agriculture, urban consumption, or industrial use

• Advantages:

  • Provides water to regions suffering from water stress by transporting it from water-rich areas

  • Helps maintain water supplies for agriculture, industry, and households during dry periods

• Limitations:

  • High cost of infrastructure and maintenance

  • Potential disruption of ecosystems in both the source and receiving areas

  • Possible introduction of invasive species

Pipelines

• Pipelines are underground or above-ground pipes that transport water over long distances from water sources to areas where it's needed

• Advantages:

  • Provide a continuous supply of clean water without overland flow, reducing exposure to pollutants

  • Can transport water to remote or arid regions

• Limitations:

  • Capacity is fixed once installed, limiting flexibility for future demand

  • Underground pipelines are difficult to monitor and repair

    • Leaks result in high level of water waste

  • Surface pipelines disrupt transport and cause visual pollution

Water tankers

• Water tankers are large vehicles (e.g. ships or trucks) used to transport water over large distances

• Advantages:

  • Can deliver water quickly to areas in critical need or emergencies

  • Provide a temporary supply during droughts or natural disasters

  • Suitable for locations with limited water sources or infrastructure

• Limitations:

  • Expensive to operate over long distances

  • Transporting large volumes of water can have a high environmental impact due to the carbon footprint

Estuary storage with barrages

• Barrages are barriers built across estuaries to store freshwater in coastal areas

• Water is trapped during high tides and used during low tides or droughts

• Advantages:

  • Provides water storage in coastal regions where natural freshwater sources may be scarce

  • Can also prevent seawater intrusion into freshwater systems, improving water quality for use

• Limitations:

  • Expensive to construct and maintain

  • Can have significant ecological impacts on estuarine ecosystems, affecting migrating fish and other marine species

  • Can alter tidal flows

Rainmaking (cloud seeding)

• Cloud seeding is a form of weather modification that involves dispersing substances (like silver iodide) into clouds to encourage precipitation

• Advantages:

  • Can increase local rainfall in drought-prone areas, helping to replenish water supplies

  • Useful for boosting agricultural productivity in arid regions

• Limitations:

  • Expensive and requires favourable weather conditions to be effective

  • Long-term environmental impacts are not fully understood

Desalination

• Desalination is the process of removing salt from seawater to make it suitable for drinking or irrigation

• It is increasingly used in water-scarce regions, especially in coastal areas with access to seawater

• Advantages:

  • Provides a reliable source of freshwater in areas where natural freshwater resources are limited

  • Can supply large populations with drinking water, especially in arid regions

• Limitations:

  • High energy consumption and expensive to operate

  • Produces a concentrated brine byproduct that can harm marine environments when discharged

Solar distillation

• Solar distillation uses solar energy to evaporate water, leaving behind impurities and salts, then condenses the vapour into clean water

• It is often used in small-scale applications

• Advantages:

  • Renewable energy source with low operational costs

  • Can provide clean drinking water in remote or arid locations

• Limitations:

  • Requires sunny conditions, so not reliable in all climates

  • Produces water at a slow rate, making it unsuitable for large-scale needs

Dew harvesting

• Dew harvesting involves capturing water vapour from the air, usually on cool surfaces, which then condenses into liquid water

• Advantages:

  • Provides a local, low-energy source of water in arid regions

  • Can be an effective water collection method in areas with low precipitation but high humidity

• Limitations:

  • Produces small amounts of water, making it unsuitable for large-scale needs

  • It requires specific environmental conditions (cool nights and high humidity)

Aquifers

Aquifer storage and recovery (ASR)

• ASR is a process where surplus water is stored in underground aquifers during times of excess, such as during the rainy season, and retrieved during dry periods

• Advantages:

  • Reduces evaporation losses compared to surface storage (e.g. in reservoirs)

  • Can help manage water supply over long periods, including during droughts

• Limitations:

  • Requires careful management to avoid contamination of the stored water

  • Can lead to over-extraction and depletion of groundwater resources if not monitored

Artificial recharge of aquifers (AR)

• AR involves artificially increasing the amount of water that enters an aquifer, typically through the use of recharge wells or by directing surface water into recharge basins

• Advantages:

  • Helps restore depleted groundwater resources, which can be used during dry periods

  • Improves water security in areas that rely heavily on groundwater for agriculture and drinking water

• Limitations:

  • Potential contamination of aquifers if surface water is polluted

  • Requires significant infrastructure and ongoing monitoring to ensure effectiveness

Environmental Impacts of Desalination

• Desalination provides a crucial solution to water stress, especially in arid regions

• However, it also has significant environmental impacts

  • The negative impacts of desalination can be reduced through technology and careful management, but they are not entirely preventable

Brine discharges

• Brine is the concentrated salty water left over after the desalination process

  • It is usually discharged back into the sea

• Environmental impact:

  • The concentrated brine can alter the salinity of coastal waters, harming marine ecosystems and reducing biodiversity

  • Brine can sink to the ocean floor, creating "dead zones" where oxygen levels are too low to support aquatic life

• Mitigation:

  • Dilution techniques can help disperse brine more evenly

Noise pollution

• Desalination plants generate significant amounts of noise during operation

  • Particularly from machinery like pumps and turbines

• Environmental impact:

  • Noise pollution can disturb nearby wildlife, especially marine animals that rely on sound for communication and navigation

  • The constant noise may also have an impact on people living close to desalination plants

• Mitigation:

  • Locating plants farther from sensitive habitats or residential areas can reduce noise pollution

Air pollution and fossil fuel combustion

• Many desalination plants use fossil fuels to power them, resulting in emissions of air pollutants such as carbon dioxide

• Environmental impact:

  • Desalination contributes to air pollution and increases greenhouse gas emissions, worsening climate change

  • For example, desalination in the UAE is extremely energy-intensive, with plants relying heavily on fossil fuel combustion to power operations

• Mitigation:

  • Transitioning to renewable energy sources, like solar or wind power, can reduce air pollution and carbon emissions

    • However, high costs and energy demands make this difficult in many cases

Saline intrusion into aquifers

• Saline intrusion occurs when saltwater enters freshwater aquifers, often caused by over-extraction of groundwater

• Environmental impact:

  • Desalination plants that pump water from aquifers can worsen the problem, contaminating freshwater sources and making them unusable

  • Coastal areas are particularly vulnerable to saline intrusion, which can affect drinking water supplies

• Mitigation:

  • Careful monitoring of groundwater levels and limiting extraction rates can reduce the risk