ENVS200-WK7.1-water2

Page 1: Introduction

• Groundwater significance highlighted through illustrations.

Page 2: Student Learning Objectives

• Understand differences between aquifers and aquitards.

• Identify various types of wells and springs.

• Explain degradation and depletion of groundwater.

• Discuss negative consequences of groundwater overuse, dams, and water transport.

Page 3: Groundwater Characteristics

• Porosity: Ability of rocks to contain fluids.

• Permeability: Ability of rocks to allow fluids to pass through.

Page 4: Groundwater Flow

• Groundwater behavior influenced by geology and geometry of rocks/sediments.

• Aquifers: High permeability and porosity, facilitating easy water flow.

• Aquitards: Low permeability, slowing or preventing water motion.

Page 5: Global Groundwater Distribution

• Visuals show the insufficient vs. sufficient groundwater supply around oceans.

Page 6: Accessing Groundwater

• Groundwater accessed via:

  • Natural springs

  • Human-made wells

Page 7: Springs

• Springs are where the water table meets the surface

• Often found in valleys with wetland vegetation and saturated soils year-round.

Page 8: Types of Wells

• Ordinary Wells: Holes into an aquifer, requiring pumping.

• Artesian Wells: Water rises on its own due to pressure.

Page 9: Ordinary Wells

• Water seeps into ordinary wells up to the water table level, requiring additional means for lifting water.

Page 10: Artesian Wells

• These wells are specifically designed to access groundwater under pressure, allowing water to reach the surface without pumping.

Page 11: Groundwater Simulations

• Engaging illustrations and simulations representing groundwater dynamics.

Page 12: Water Sufficiency Concerns

• Freshwater being used unsustainably through

  • Faster extraction than natural replenishment

  • Wasting and polluting water resources.

  • One in ten people lacks access to clean water.

Page 13: Water Resources

• Surface Water: Freshwater from rain and snow.

  • 34% of reliable surface runoff utilized annually.

  • 70% for agriculture, 20% industrial use, and 10% urban usage.

• Indirect water usage contributes significantly to global water footprints.

Page 14: Causes of Water Scarcity

• Factors: Dry climate, drought, overuse, inefficient water use.

• Freshwater scarcity stress relates to availability versus human demand.

• Global water basins often shared among multiple countries, sometimes contentiously.

Page 15: River Basins and Water Scarcity Stress

• Different major river basins exhibit varying levels of freshwater scarcity stress.

Page 16: Water Quality Threats

• Global quality and quantity of freshwater supplies are threatened.

• 1.2 billion people lack access to clean drinking water.

• Over-extraction causes lowering of water tables, drying springs, and seawater intrusion.

Page 17: Global Water Demand vs. Supply

• Rapid population growth leads to high water demand with limited new sources available.

Page 18: Average Annual Precipitation

• Statistics on average annual precipitation across various regions.

Page 19: California Water Engineering

• About 70% of rivers engineered to move water between Northern and Southern California.

  • Key projects: Los Angeles Aqueduct, California Aqueduct, Colorado River Aqueduct.

Page 20: Future Water Resources

• Groundwater over-extraction threatens food production and urban supply.

• Water transfer projects can disrupt ecosystems but expand distribution.

• Desalination is an expensive but viable option for augmenting freshwater supplies.

Page 21: Consequences of Over-Use

• Over-pumping limits food supply and raises prices, impacting affordability.

• Lowering water tables necessitates deeper and costlier wells.

Page 22: Water Table Dynamics

• Overextraction leads to cone of depression around wells, affecting availability.

Page 23: Wells Running Dry

• Wells may run dry before complete depletion of the water table occurs, prompting deeper installations.

Page 24: Saltwater Intrusion

• Occurs near coastlines, poisoning wells and rendering them unusable.

Page 25: Saltwater Dynamics

• Freshwater density compared to saltwater affects intrusion; rapid extraction moves saline boundaries towards wells.

Page 26: Mitigation Strategies

• Pumping treated freshwater back into the ground to prevent saltwater intrusion.

Page 27: Aquifer Compaction

• Post-extraction, sediments undergo readjustment, leading to compaction and decreasing porosity.

Page 28: Consequences of Compaction

• Compaction can cause land subsidence and irreversible damage to infrastructure.

Page 29: Infrastructure Damage

• Subsidence leads to destruction of essential structures without hope of recovery.

Page 30: Subsidence Statistics

• Illustrative measurements of subsidence in California show significant vertical changes.

Page 31: Sinkholes

• Rapid subsidence due to groundwater removal leads to dangerous ground collapses.

Page 32: Groundwater Contamination

• Often unnoticed until significant damage occurs; cleanup is slow and expensive.

Page 33: Sources of Pollution

• Common contaminants: fertilizers, animal sewage, industrial waste affecting aquifers.

Page 34: Dams and Water Transfer

• Dams block river flow, creating reservoirs; vital for water management.

Page 35: Advantages of Dams

• Benefits include flood control, irrigation, electricity generation, and recreation.

Page 36: Disadvantages of Dams

• Dams displace populations, flood lands, and disrupt ecosystem functions.

• Average lifespan limits their effectiveness.

Page 37: Water Transfer Impact

• Water transfer diminishes river flow, increases pollution, threatens fisheries, and promotes water wastage.

Page 38: Evaluating Dam Pros and Cons

• Encouragement to consider the most impactful advantage and disadvantage concerning dams.

Page 39: Desalination Overview

• Process of removing soluble salts from seawater; techniques include distillation and reverse osmosis.

Page 40: Desalination Drawbacks

• High costs, chemical waste harming ecosystems, and significant brine production.

Page 41: Proposed Desalination Facility

• Details of a desalination plant project near Huntington Beach with environmental considerations.

Page 42: Existing Desalination in California

• Summary of California's desalination facilities, featuring the Carlsbad project as the largest.

Page 43: Future of Water Resources

• Ongoing challenges related to aquifer depletion, water transfer impacts, and desalination costs.

Page 44: Freshwater Scarcity Stress

• Factors influencing the assessment of freshwater availability against human consumption.

Page 45: Strategies for Water Supply Extension

• Three main strategies: conservation, desalination, interbasin transfers to manage water resources effectively.

Page 46: California Water Project

• Overview of a project aimed at enhancing water transport across the state.

Page 47: Supplementary Resources

• Link to further information on water projects.

Page 48-49: Closing Remarks

• Concluding content from the course related to water resource management.