Water Resources and Pollution

Chapter 14: Water Resources

Water Demand in the Desert

  • Colorado River: 2300-kilometer river historically provided significant water supply across the Southwest to Mexico's Gulf of California.

    • Colorado River Compact (1922): Agreement among seven states (Arizona, California, Colorado, Nevada, New Mexico, Utah, Wyoming) to utilize the river's water for human use.

    • Current situation:

    • Severe drought, dam constructions, and water diversions have drastically reduced the river's flow, leading to it running nearly dry.

    • Las Vegas officials proposed mining groundwater in the Great Basin Desert as a controversial alternative source of water.

  • Discussion Point: Consideration of ecological impacts versus human necessity for fresh water.

Water Distribution

  • Fresh Water: Defined as both a renewable and limited resource. It is distributed unevenly across the planet, influencing usage based on location and time of year.

  • Comparison: If Earth's water were in a two-liter bottle, only roughly two capfuls would represent fresh, liquid water.

Surface Water

  • Definition: Includes still bodies of water and river systems.

  • Watersheds: Areas that drain into a river system; every waterway defines its watershed.

  • Mississippi River Basin: Third largest watershed globally, covering 3 million square kilometers and draining 41% of the contiguous U.S. land area.

Groundwater

  • Aquifers: Underground layers of permeable rock and soil that hold water. They recharge slowly, averaging about 1400 years for groundwater age.

  • Water Table: Separates the saturation zone from the aeration zone.

  • Daily Groundwater Release: Aquifers release about 1.9 trillion liters (492 billion gallons) of groundwater daily through springs, geysers, and wells.

Water Usage Breakdown

  • Usage Statistics:

    • Agricultural: 70% (primarily for irrigating crops)

    • Industrial: 20% (cooling of machinery)

    • Personal: 10% (daily household consumption)

  • American Average: An average American uses approximately 250 liters of fresh water daily for personal uses (bathing, brushing teeth).

Virtual Water

  • Definition: The concept of the water embedded in the production of food and other products.

Surface Water Management

  • Usage: Majority of U.S. freshwater sourced from surface water, often diverted using canals and dams.

  • Issues: Drought and overuse have led to significant depletion of surface water resources.

Groundwater Management

  • Irrigation: 68% of groundwater in the U.S. is utilized for inefficient irrigation practices.

  • Consequences of Groundwater Mining: Depleting groundwater turns a renewable resource into a nonrenewable one, impacting the stability of cities and potentially allowing saltwater intrusion into aquifers.

Solutions for Freshwater Depletion
Increasing Supply

  • Desalination: Process of converting saltwater to freshwater by removing salts.

Decreasing Demand

  • Agricultural practices: Implementing drip irrigation and utilizing climate-appropriate plants.

  • Industrial Solutions: Promoting water-conserving processes and recycling wastewater.

  • Personal Practices: Engaging in xeriscaping (landscaping design designed for water conservation).

Water Pollution Types

  1. Point-source pollution: Originates from a specific location, such as factories.

  2. Nonpoint-source pollution: Arises from widespread areas, e.g., snowmelt runoff collecting pollutants.

Nutrient Pollution

  • Definition: Occurs due to excess nutrients, such as phosphorous, leading to algae blooms (eutrophication).

  • Eutrophication Process: Nutrient build-up leads to increased algae growth, subsequent organism die-off, followed by reduced dissolved oxygen levels due to decomposition.

Toxic Chemical Pollution

  • Definition: Involves the release of harmful chemicals into water sources, affecting ecosystems and human health.

Sediment and Thermal Pollution

  1. Sediment Pollution: Results from erosion, leading to degraded water quality and disrupted ecosystems.

  2. Thermal Pollution: Occurs when heated water is released into waterways, affecting oxygen levels.

Biological Pollution

  • Definition: Introduction of pathogens into water, leading to significant health risks for humans.

  • Reduction Methods: Treatment processes aimed at lowering biological contaminants.

Groundwater Pollution Sources

  • Originates from natural sources, surface contaminants leaching through soil, and deteriorating underground structures.

  • Chemicals in groundwater decompose slower compared to surface water.

Ocean Water Pollution

  • Oil Pollution: Primarily from small sources and natural seeps; mercury accumulation in marine life is highlighted.

  • Red Tides: Result from nutrient pollution affecting oceanic ecosystems.

Controlling Water Pollution

  • Legislation:

    • Clean Water Act: Establishes standards and requires permits for point-source pollution.

    • Regulatory efforts have demonstrated successful cleanup, exemplified by the restoration of Lake Erie.

Water Treatment

  • Treatment processes remove pollutants from drinking water to ensure safety before consumption and manage wastewater effectively.

Chapter 19: Waste Management
Fresh Kills Landfill

  • Largest landfill globally, located on Staten Island, closed in 2001.

  • Currently transitioning into a public park, shifting focus from landfills to waste reduction.

Understanding Waste

  • Definition: Unwanted materials resulting from human activities.

  • Types of Waste:

    • Municipal Solid Waste: From homes/businesses.

    • Industrial Waste: From manufacturing, agriculture, mining.

    • Hazardous Waste: Toxic, reactive, flammable materials.

    • Wastewater: Discarded water and runoff.

Solid Waste Disposal Methods

  1. Sanitary Landfills: Designed to minimize contamination and pollution, with regulations dictating construction features such as height above the water table.

Landfill Effectiveness

  • Benefits: Methane generation for energy use, land transformation for recreational use.

  • Negatives: Leachate risks contaminating groundwater; slow decomposition leads to prolonged waste issues.

Incineration Process

  • Waste-to-energy facilities burn solid waste, generate steam, and produce electricity through turbines.

  • Pollution Control: Systems like scrubbers and baghouses reduce toxic emissions.

Eco-Friendly Practices

  • Waste Reduction: Strategies such as reusables, packaging minimization, and consumer incentives (e.g., pay-as-you-throw).

Waste Recovery Practices

  • Composting: Organic waste transformed into usable mulch/humus.

  • Recycling: Varies greatly across communities in U.S.; some programs may operate at a loss.