Lecture 19 - The Blue Planet

Lecture 19 - The Blue Planet

Consider Water (Will Langford)

• Prompt for Brainstorming: Students to think about and discuss their daily water consumption.

  • Common Uses Identified: Drinking, showering, washing dishes, laundry, and food-related uses.

  • Estimates of Daily Use: Varying estimates of personal water use noted, highlighting difficulty in accurately assessing consumption.

Societal Water Uses

• Engagement with Water Uses: Discussion on broader uses of water beyond personal consumption.

  • Highlighted Areas: Manufacturing, agriculture, recreational use (swimming pools, aquariums), and scientific research.

Our Blue Planet (Will Langford)

• Global Perspective: Water scarcity affects one in six people globally; urgent issues developed regarding access rights to clean water.

• Social Conflicts Around Water: Examples include boil-water advisories in some communities and international disputes over water resources, emphasizing the need for effective resource management.

Key Water Facts

• Total Water on Earth: Approximately 1.4 billion cubic kilometers; only 2.5% is freshwater.

• Usable Freshwater: Less than 1% of available resources (around 200,000 cubic kilometers), essential for human consumption and activity.

• Water Distribution: Most available freshwater is stored underground in aquifers; societal allocation varies by location and infrastructure.

Watershed Concept

• Watershed Defined: Drainage basins that collect and direct water flow; fundamental for managing water resources effectively.

• Importance of Wetlands and Forests: Critical for retaining water and replenishing aquifers, protecting ecosystems.

Aquifers and Water Management

• Types of Aquifers: Surface aquifers recharge quickly; deeper aquifers recharge over centuries due to permeable rock layers.

• Fossil Water Concept: Drawing on deep aquifers provides ancient water reserves but creates sustainability issues due to long recharge times.

• Human Impact: Intensive draw from aquifers can lead to depletion, necessitating alternate management strategies.

Health and Water Consumption

• Human Body Composition: Water constitutes around 55-60% of human body weight; daily needs for hydration range from 2-4 liters.

• Importance of Clean Water: Lack of access to clean water leads to preventable diseases impacting mortality rates, highlighting public health vulnerabilities.

Water Footprint of Food Production

• Water Usage Estimates: Different foods have varying water footprints; for example, producing one kilogram of beef can require up to 15,000 liters.

• Agriculture’s Role: About 70% of freshwater use globally is for irrigation, reflecting its significant demand on water resources.

Water, Disease, and Public Health (Steve Mannell)

• Water and Filth in Industrial Cities: The link between water supply systems and public health became crucial during cholera epidemics, leading to improved sanitation practices.

• Cholera Epidemics and Public Health Movement: John Snow's investigation into cholera outbreaks marked a pivotal advancement in understanding waterborne diseases, influencing infrastructure enhancements.

The Quest for Pure Water (Steve Mannell)

• Filtration and Public Health Advancements: Recognition of filtration processes, including slow sand filtration, led to improvements in the quality of drinking water and public health.

• Schmutzdecke Concept: The biological layer in filters proving essential to purifying water revealed complexities beyond traditional mechanical filtration methods.