Water management Flashcards
What percentage of Earth’s fresh water is available for human use, and where are water-scarce regions typically located?
97% of global water is saline.
3% is fresh, with 2% in glaciers, leaving 1% accessible.
High scarcity near the Equator (e.g., North Africa).
Describe the term Water Deficit
Occurs when water demand exceeds supply in a region.
Caused by factors like drought, overuse, population growth, or poor infrastructure.
Common in arid climates (e.g., North Africa, Middle East) and areas with seasonal dry periods.
Leads to water scarcity, crop failure, and conflicts over resources.
Describe the term Water surplus
Occurs when water supply exceeds demand in a region.
Common in humid climates (e.g., tropical rainforests, temperate regions) with high rainfall or snowmelt.
Can lead to flooding, soil erosion, and waterlogging.
How does economic development increase water demand, and what are key examples?
As a country develops, rising standard of living drives higher water use through:
Mechanization – More water for industry ).
Labour-saving devices – Washing machines, dishwashers.
Luxury/outdoor use – Car washing, gardening, swimming pools, hot tubs.
Personal hygiene – Shift to frequent showers
Leisure/tourism – Water parks, spas, golf course irrigation.
What are the three main causes of water supply problems in the UK?
Geographical imbalance: High rainfall in low-population areas (e.g., Wales/Scotland) vs. low rainfall in high-demand areas (e.g., SE England).
Seasonal imbalance: More winter rain; summer droughts worsen shortages (e.g., 2010–2012 drought).
Ageing infrastructure: Leaky pipes lose 3.26 billion litres/day; repair costs exceed £100 billion.
What are the key challenges of untreated water in developing countries?
663 million people (1 in 10) lack safe water; Africa is worst affected.
Health impacts: Waterborne diseases (e.g., diarrhoea kills ~2000/day) and parasites.
Barriers: Governments lack funds for treatment infrastructure.
Why are watercourses polluted in developing nations?
Agriculture: Fertilizers/pesticides from unregulated farming.
Mining: Toxic runoff .
Sanitation: Faeces contamination due to poor waste education/infrastructure.
How does low rainfall exacerbate water problems in developing countries?
Causes: Climate change, population growth, and seasonal droughts (e.g., Sahel region).
Consequences: Extreme shortages in Chad/Mali; food insecurity and migration.
How are individuals in Las Vegas addressing water scarcity?
Positive Action: Some adopt xeriscaping (replacing grass with desert plants like cacti to reduce water use).
Resistance: Others refuse to give up lawns due to aesthetic preferences.
What sustainable practices do Las Vegas organizations use to conserve water?
Example: Casinos like the Bellagio recycle wastewater for fountains and irrigation.
Impact: Reduces demand on freshwater supplies despite high-visibility water features.
Contrast: Luxury water displays vs. conservation efforts spark debate.
How is the Las Vegas government promoting water sustainability?
Financial Incentives: Pays residents to replace lawns with desert gardens.
Regulations: Bans grass in front gardens of new homes.
Result: Outdoor water use dropped by 30% since 2000, despite population growth.
What is desalination, and how does it work?
Definition: The process of removing salt from seawater/brackish water to make it drinkable.
Methods:
Reverse Osmosis (most common): Forces water through semi-permeable membranes.
Thermal Distillation: Heats water to evaporate and condense freshwater.
Output: Produces freshwater + concentrated brine (waste).
What are the advantages of desalination?
Reliable Supply: Provides water in arid regions (e.g., UAE, Israel).
Scalability: Can support large populations (e.g., Singapore’s NEWater).
Drought-Proof: Unaffected by rainfall variability.
Key Stat: Global desalination capacity exceeds 100 million m³/day.
What are the drawbacks of desalination?
High Energy Use: Reverse osmosis requires 3–10 kWh/m³ (costly and carbon-intensive).
Brine Disposal: Harmful to marine ecosystems if not managed.
Cost: Expensive infrastructure (~$1/m³) limits use in poor countries.
Trade-off: Balances water security with environmental/economic costs.
How does the UK promote sustainable water use?
Water Companies:
Treat wastewater for reuse.
Install water meters to reduce consumption.
Public education on conservation.
Government Policies:
“Water-neutral” development rules.
Mandate water-efficient homes (e.g., low-flush toilets, rainwater harvesting).
What are the UK’s main water challenges and responses?
Problems: Uneven rainfall (SE England <800mm/year), ageing pipes (lose 3.26B litres/day).
Solutions:
Transfer schemes (e.g., Wales → Birmingham).
£100B needed to fix infrastructure.
Stat: 30% drop in outdoor water use due to lawn replacement incentives.
Why does China face severe water shortages?
Imbalance: North (45% population, 20% water) vs. South.
Pollution: 40% rivers contaminated; 80% lakes eutrophic.
Climate Change: More droughts, erratic monsoons.
Stat: 300M rural lack safe water.
Evaluate China’s South-North Water Transfer Project.
Pros: Moves 45B m³/year to arid north.
Cons:
Polluted water requires costly treatment.
Displaced 330K people; high energy use.
Verdict: Partial success; sustainability focus now preferred.
How has China improved agricultural water efficiency?
Tech: Micro-sprinklers, lined irrigation channels.
Farming: Drought-resistant crops, straw-mulching.
Monitoring: Soil moisture sensors in rice fields.
Result: Irrigation efficiency >50% by 2014.
How do Chinese cities conserve water?
Wastewater Recycling: 85% in Beijing (22% of total supply).
Rainwater Harvesting: Mandatory in public buildings.
Price Controls: Incentivize conservation.
Stat: Beijing’s water use declined despite population doubling since 1980.
