C13. Water Resources

Introduction to Water Resources

• Instructor: Tess Lesniak M.S.

Water Conservation Tips

• 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.

The State of Freshwater Management

• 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

Availability of Freshwater

1. 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.

2. Surface Water: Derived from precipitation/snowmelt, includes surface runoff.

   • Watersheds: Areas that collect surface water and direct it to bodies of water.

Increasing Water Use

• Hydrologists study water supplies and usage.

  • Global water usage breakdown: 70% for irrigation, 20% for industry, 10% for residential.

Water Footprint and Virtual Water

• 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.

Freshwater Resources in the U.S.

• 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.

Future of Freshwater Resources

• Global Challenges:

  • Increased droughts in dry climates due to long periods with low precipitation (currently below 30%).

Water Conflicts in the Middle East

• 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).

Groundwater Depletion Prevention Strategies

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

Large Dams and Reservoirs

• Advantages:

  • Control floods, generate electricity, and provide irrigation.

• Disadvantages:

  • Displacement of people, ecological impairment, and loss of biodiversity.

Case Studies on Water Dams

• 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 Challenges

• Desalination Processes:

  • Distillation: Heating seawater to evaporate salt.

  • Reverse osmosis: Forcing seawater through membranes.

  • Concerns include high costs, energy requirements, and brine disposal issues.

Sustainable Water Use Solutions

• 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.

Water Pollution: Causes and Effects

• 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.

Water Pollution Control Measures

• Historical context of water pollution laws improving river conditions (e.g., Cuyahoga River).

• Challenges remain, as many areas still face serious pollution.

Eutrophication and Lakes

• Natural Eutrophication: Nutrient enrichment leading to algal blooms due to nutrient runoff.

  • Involves dangers to aquatic life and oxygen depletion.

Great Lakes Case Study

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

Groundwater Pollution

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

Innovative Water Purification Technologies

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

Water Conservation Practices

• Simple actionable steps for individuals to save water at home.

Vocabulary

• 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.

Review Questions

1. Water usage distribution in irrigation, industry, and homes.

2. Definition and applications of greywater.

3. Comparison of water footprints in America vs China.

4. Understanding the significance of the virtual water footprint.

5. Two methods for farmers to conserve irrigation water.

6. Issues facing the Colorado and Nile Rivers.

7. Natural self-cleaning processes in streams.

8. Personal water footprint reduction strategies.