Global Water Demand, Scarcity, and Sustainability
Global Water Demand: Factors and Trends
The demand for water is steadily increasing due to several key factors:
- Rising world population
- Increased irrigation for food production
- Improved living standards
- Higher domestic water consumption
Water Use by Sector
Domestic: Use in homes, including water disposal.
Industrial: Use in factories and for power generation, particularly in North America and Europe.
Agricultural: Use for irrigation, which is the primary water-consuming activity in Asia and Africa.
Disparities in Water Availability
Developed countries: In Europe and North America, 100% access to piped, clean water is generally taken for granted.
Developing countries: Approximately 71% of the population has easy access to safe water.
In rural areas, less than 25% of the population has access to sanitation facilities, and in some areas, no one has access.
Why is Access to Safe Water Higher in Urban Areas?
- Higher incomes among urban populations
- Greater wealth in cities
- Increased political pressure on leaders to improve infrastructure
- Easier and cheaper construction of water pipes in densely populated areas
- Concentration of wealthy individuals in cities
Lack of clean water and sanitation significantly impacts public health, leading to water-related diseases and increased mortality.
Flooding and Drought: Causes and Effects
Flooding | Drought | |
Causes | – Significantly higher than usual rainfall increases surface runoff, overwhelming rivers and streams. Similar issues occur in mountain areas during summer snowmelt. – Increased runoff occurs at the expense of interception and infiltration. Interception: Decreases as trees and leaves become saturated. Infiltration: Decreases as soil spaces become filled with water. – Deforestation and urbanization contribute to increased flood risk in valleys. | – Extended periods of dry weather, often due to abnormal wind and pressure patterns, prevent rainfall. – High air pressure, rather than low, causes air to sink instead of rising, reducing the likelihood of rain. – Air must rise and cool for rain to form. – This is a common issue in Northern India during the wet monsoon season. |
Effects | Immediate: Fatalities, destruction of homes, flooding of businesses, loss of livestock, crop damage, and disruption of roads, bridges, and communication. Short term: Need for medical treatment, homelessness, water-related diseases, shortages of safe drinking water and food, and transportation difficulties. Long term: Repair and reconstruction of infrastructure, restoration of essential services (water and sewage), farmland reclamation, and replacement of livestock and seeds. | Immediate: Reduced crop yields in farming areas and livestock deaths due to a lack of grazing. Short term: Food shortages leading to malnutrition, famine, and death, with infants being particularly vulnerable. Long term: As surface water levels decline, both rural and urban populations rely more heavily on underground water sources. |
Water Pollution: Sources and Impacts
Causes:
- Industry: Metal leaching, chemicals, and heavy metals from waste heaps contaminate rivers.
- Agriculture: Pesticides, fertilizers, and animal manure used to enhance crop yields can leach into groundwater or be washed into surface water.
- Domestic waste: Organic matter (sewage, food waste), chemicals (metals, detergents), and plastics introduce toxic substances into water bodies.
Consequences:
- Risks to human health: Increased incidence of water-related diseases.
- Environmental damage: Eutrophication and harm to aquatic ecosystems.
- Contamination of water stores: Pollution of lakes and aquifers.
Eutrophication
- Introduction of fertilizers and waste from farms and factories into water bodies.
- Increased nutrient content in rivers and lakes.
- Rapid growth and multiplication of algae.
- Decomposition of dead algae by decomposers.
- Depletion of oxygen, leading to fish deaths.
Water Supplies from Natural Sources
Water supplies are often concentrated in or near mountainous regions due to:
- Higher precipitation levels.
- Summer snowmelt releasing fresh water.
- Presence of lakes at the bottom of steep-sided mountain valleys.
Formation of an Aquifer
- Underground rocks that slowly allow water to pass through them.
- Aquifers are crucial sources of clean, usable water for human consumption.
As areas are deforested, flooding becomes more frequent because there is less land to absorb the excess water.