Water Management: A Global Challenge
Global Water Availability
Water covers ~71% of the Earth's surface, but only 2.5% is freshwater, and most of that is locked in ice caps and glaciers. Less than 1% of all water is available for human use (rivers, lakes, groundwater).
Water Surplus and Deficit
- Water surplus — areas where supply exceeds demand (e.g. Canada, Brazil, Scandinavia, Russia) — typically high rainfall, low population density
- Water deficit — areas where demand exceeds supply (e.g. North Africa, Middle East, parts of India, southwest USA) — low rainfall, high population, agriculture-intensive
Over 2 billion people worldwide lack access to safely managed drinking water, and approximately 4 billion experience severe water scarcity for at least one month per year.
Why Demand for Water is Increasing
- Population growth — world population has more than doubled since 1970
- Economic development — industrial growth requires vast water quantities (manufacturing, cooling)
- Agriculture — irrigation accounts for ~70% of global freshwater use; demand grows as diets shift towards meat (which requires far more water per calorie than crops)
- Rising living standards — more showers, washing machines, swimming pools, watered gardens
Impacts of Water Insecurity
| Impact | Details |
|---|---|
| Health | Contaminated water causes waterborne diseases — diarrhoea, cholera, typhoid kill ~485,000 people/year; children under 5 most vulnerable |
| Food production | Without reliable irrigation, crop yields fall; livestock need water; drought causes famine |
| Industrial output | Manufacturing, mining, and energy production all require water; shortages limit economic growth |
| Conflict | Competition for water can cause tension — e.g. disputes over the Nile (Egypt, Sudan, Ethiopia and the Grand Ethiopian Renaissance Dam); Jordan River (Israel, Jordan, Palestine) |
| Gender and education | In many LICs, women and girls spend hours daily collecting water, preventing school attendance and employment |
| Migration | Water scarcity drives people to move — "water refugees" |
Strategies to Increase Water Supply
Large-Scale Engineering
Dams and reservoirs:
- Store water during wet seasons for use during dry periods; also generate hydroelectric power
- Example: Three Gorges Dam, China — world's largest hydroelectric dam; reservoir 600 km long; 22,500 MW capacity
- Advantages: reliable water supply; flood control; HEP generation; irrigation
- Disadvantages: 1.3 million people displaced; ecosystems flooded; sedimentation reduces lifespan; downstream water flow reduced
Water transfer schemes:
- Moving water from areas of surplus to deficit via pipelines, canals, or rivers
- Example: China's South-North Water Transfer Project — diverts water from the Yangtze River to the drier north; 1,400 km eastern route; cost over $60 billion; supplies Beijing and Tianjin
- Example: Libya's Great Man-Made River — 2,800 km of pipelines pump fossil water from Saharan aquifers to coastal cities
Desalination:
- Removing salt from seawater to produce freshwater
- Major use in the Middle East — Saudi Arabia produces ~50% of the world's desalinated water
- Advantages: unlimited source (seawater); reliable supply
- Disadvantages: very expensive; extremely energy-intensive (high carbon footprint unless using renewables); brine waste harms marine ecosystems
Sustainable/Local-Scale Solutions
Rainwater harvesting:
- Collecting and storing rainwater from roofs and surfaces
- Used widely in India, Brazil, and sub-Saharan Africa
- Low-cost and locally maintainable
- Example: In Rajasthan, India, traditional "johads" (earthen check dams) have been revived — over 8,600 built by community organisation Tarun Bharat Sangh, raising water tables in 1,000+ villages
Wells and boreholes:
- Accessing groundwater — hand-dug wells or deeper boreholes with pumps
- WaterAid has installed thousands of boreholes across sub-Saharan Africa
- Risk of over-extraction lowering the water table; contamination if not properly lined
Water recycling:
- Treating wastewater for reuse in irrigation, industry, or even drinking water
- Example: Singapore's NEWater — treats used water through advanced membrane technology; supplies up to 40% of the nation's demand; used mainly for industry
Appropriate technology:
- Solutions suited to the local context, affordable, and maintainable by the community
- Play pumps — children's roundabouts that pump groundwater as they spin (though some criticised as less efficient than hand pumps)
- LifeStraw — portable water filter removing bacteria and parasites; used in emergencies and remote communities
- Fog nets — mesh screens that collect water droplets from fog in coastal deserts (e.g. Morocco, Chile)
Water Management in an LIC: WaterAid in Mali
Mali is a landlocked LIC in West Africa where only ~77% of the population has access to basic drinking water (far lower in rural areas).
WaterAid projects in Mali:
- Installed wells and hand pumps in rural communities
- Built latrines to improve sanitation and reduce waterborne disease
- Trained local communities to maintain their own water points — ensuring sustainability
- Educated communities about hygiene practices (handwashing)
- Worked with local government to improve policy and funding for water/sanitation
Exam tip: Be prepared to compare large-scale (top-down) and small-scale (bottom-up) approaches to water management, evaluating their sustainability, cost, environmental impact, and appropriateness for different contexts.