Water Resources Notes

Freshwater is crucial for:
- Supplying food and shelter
- Sculpting the earth’s surface
- Moderating climate
- Diluting wastes and pollutants
It is poorly managed:
- Wasted and polluted regularly
- Pricing does not reflect its importance.

Access Issues:
- Global health issue, causing the death of approx. 3,900 children under 5 daily due to waterborne diseases.
- Economic issue crucial for reducing poverty and food production.
- Primarily affects women and children in developing countries, who often have to fetch water.
Security Issues:
- National and global security is threatened by tensions over shared water resources.
Environmental Concerns:
- Excessive water withdrawal leads to dropping water tables and environmental degradation.

Only 0.024% of the earth’s water is liquid freshwater available for use.
Much of the freshwater is trapped in ice caps, glaciers, and deep underground sources.

The hydrologic cycle involves continuous collection, purification, recycling, and distribution of freshwater.
Human activities (pollution, over-extraction, and climate change) can disrupt this cycle.

Freshwater is not evenly distributed globally; certain areas possess abundant and others scarce supplies.
Example: Canada has 20% of the world’s liquid freshwater, while China has only 7% despite having 19% of the population.

Groundwater:
- Infiltrates the ground, percolating through soil and rock, filling aqautifers.
- Water table indicates the upper surface of saturated groundwater.
Surface Water:
- Freshwater from precipitation and melted snow flows into various bodies of water.
- Watershed is the land area draining into a particular water body.

Human population tripled in the last century, raising global water withdrawals significantly.
Presently, about 70% of freshwater withdrawals support irrigation, while industry and residences account for 20% and 10% respectively.

Major causes include:
- Dry climate and drought conditions
- Overuse of water supplies
- Water wastage
Over 30 countries are currently facing water scarcity; by 2050, 60 countries will likely experience water stress.

Groundwater is being extracted faster than it can be replenished in many regions.
Over 1 billion people lack regular access to clean water, and this number may rise to 3 billion by 2025.

Advantages:
- Provides drinking water and irrigation
- Renewable unless over-extracted or contaminated
- Easier to extract than surface water
Disadvantages:
- Risk of aquifer depletion and land subsidence
- Persistent pollution issues

Dams create reservoirs to capture and store water, providing irrigation, electricity, and recreation options.
However, they displace millions, cause ecological issues, and lose functionality over time due to sediment fill-up.

Waste reduction strategies:
- Increase prices to minimize waste
- Limit wells and crop types in dry areas
- Promote water conservation measures

Involves removing salt from seawater but is costly and ecologically harmful, creating briny wastewater.
Techniques: Distillation and reverse osmosis.

Globally, 66% of freshwater used is wasted. In the U.S., about half of freshwater is lost.
Techniques for reducing waste include improving irrigation efficiency and fixing leaks.
- Encourage using water-saving fixtures and practices at home.

Individuals play a role in promoting sustainable water practices by conserving, repairing leaks, and changing personal habits.
Implementing systems for gray water reuse and promoting conservation can significantly impact global freshwater availability.