C13. Water Resources

Tip #1: Fill a clean two-liter container with water and rocks, cap it, and sink it in the toilet tank (away from float mechanism).
- Saves approximately 380 gallons of water/month for a family of 5, considering the average American flushes 5 times/day.
Tip #2: Only flush for solids to significantly reduce water usage and costs.

Freshwater is crucial for human survival, but resources are poorly managed.
- Annual precipitation and economic factors create disparities: water haves and have-nots.
- Source: www.usgs.gov

Groundwater: Collected in the zone of saturation beneath the earth's surface, flowing through aquifers.
- Types of Aquifers:
  - Unconfined Aquifers: Quickly replenished.
  - Confined Aquifers: Slowly replenished.
  - Nonrenewable Aquifers: Finite resource; formed over thousands of years.
Surface Water: Derived from precipitation/snowmelt, includes surface runoff.
- Watersheds: Areas that collect surface water and direct it to bodies of water.

Hydrologists study water supplies and usage.
- Global water usage breakdown: 70% for irrigation, 20% for industry, 10% for residential.

Average American usage: 80-100 gallons/day.
- Breakdown of uses: Flushing toilets (27%), Washing clothes (22%), Showers (17%), Faucets (16%), Leaks (14%).
Water Footprint: Total volume of direct and indirect water consumption, including food production.

The U.S. has sufficient renewable freshwater, but distribution is uneven.
- West regions face surface water shortages, depleting aquifers, and land subsidence issues.
- Technological advancements have stabilized water usage despite a 30% population increase since 1975.

Global Challenges:
- Increased droughts in dry climates due to long periods with low precipitation (currently below 30%).

High population growth and water shortages create tension over shared resources (e.g., Nile, Jordan, Tigris-Euphrates rivers).
- Egypt faces hydrological poverty due to upstream diversion (e.g. Sudan's plans to divert the Nile).

Control water use efficiently, raise water prices to discourage waste, and introduce sustainable practices such as rain gardens in urban settings.

Advantages:
- Control floods, generate electricity, and provide irrigation.
Disadvantages:
- Displacement of people, ecological impairment, and loss of biodiversity.

Colorado River: Numerous dams have led to an ecological crisis at its mouth.
Aral Sea Disaster: Diverted rivers for agriculture led to ecological and economic collapse.

Desalination Processes:
- Distillation: Heating seawater to evaporate salt.
- Reverse osmosis: Forcing seawater through membranes.
- Concerns include high costs, energy requirements, and brine disposal issues.

Emphasis on reducing water waste, improving efficiency, and raising prices to promote conservation.
- Comparison of strategies between South Africa and Israel in cutting irrigation water loss.

Definition: Water quality changes making it harmful for organisms.
- Pollution Sources:
  - Point sources (e.g., pipes) and non-point sources (e.g., agricultural runoff).
- Main Pollutants: Pathogens, chemicals, and excessive heat.

Historical context of water pollution laws improving river conditions (e.g., Cuyahoga River).
Challenges remain, as many areas still face serious pollution.

Natural Eutrophication: Nutrient enrichment leading to algal blooms due to nutrient runoff.
- Involves dangers to aquatic life and oxygen depletion.

U.S. and Canada invested significantly in pollution control; successes in ecosystem restoration noted.

Common issues include leaking industrial waste ponds, agricultural runoff, and fracking.

Living Machines: Natural systems that utilize biodiversity for purification without chemical treatment.

Terms to know: groundwater, aquifer, water table, surface water, surface runoff, watershed, water footprint, virtual water footprint, drought, desalination, floodplain, water pollution, point and nonpoint sources, eutrophication, cultural eutrophication.