Chapter 6: Sustaining Water Supplies

Chapter 6: Sustaining Water Supplies

Fresh Water Supplies Shrink as Demand Increases

“Water, water, every where, Nor any drop to drink.”

Central Question

6.1-6.2 Science

6.1 The hydrologic cycle moves water around Earth

The Distribution of Earth’s Water

DISTRIBUTION OF EARTH’S WATER

Water Moves Among Reservoirs

Think About It

6.2 The El Niño Southern Oscillation causes periods of dry years and wet years

TEMPERATURE AND ATMOSPHERIC PRESSURE DIFFERENCES ACROSS THE PACIFIC OCEAN DURING EL NIÑOS AND LA NIÑAS

WESTERN PACIFIC OCEAN

EASTERN PACIFIC OCEAN

WESTERN PACIFIC OCEAN

EASTERN PACIFIC OCEAN

El Niño Southern Oscillation

Think About It

6.1-6.2 Science: Summary

6.3–6.6 Issues

6.3 Access to adequate water supplies as a human right

Daily Water Needs

Water as a Human Right: The Challenges

AVERAGE PER CAPITA WATER USE AROUND THE WORLD

Think About It

6.4 Humans already use most of the world’s accessible freshwater supplies

Arid Regions Have Maxed Out Their Water Supplies

Droughts and Floods Make Water Planning Difficult

Colorado River Basin

EARTH’S ARID REGIONS

DROUGHT CAN BE HIGHLY REGIONAL

Think About It

6.5 Groundwater is being depleted faster than it is replenished

IN MANY REGIONS, WE ARE “MINING” GROUNDWATER

Ogallala Aquifer

GROUNDWATER RECHARGE AND WITHDRAWAL IN AQUIFERS AROUND THE WORLD

Subsidence and Depletion

Think About It

6.6 Managing water for human use threatens aquatic biodiversity

groundwater depletion

GROUNDWATER DEPLETION CAN CHANGE THE FACE OF THE LAND

Dams and Aquatic Biodiversity

DAMS SIGNIFICANTLY CHANGE RIVER ENVIRONMENTS

HUMAN IMPACTS ON FRESHWATER ENVIRONMENTS ENDANGER MANY SPECIES

Water Management and Wetland Biodiversity

RIBBONS OF GREEN THROUGH DESERT LANDSCAPES

Think About It

6.3–6.6 Issues: Summary

6.7-6.10 Solutions

6.7 Water conservation can increase water use efficiency substantially

Water Conservation in a Large City

Gauging Conservation Progress

Conservation by Commercial and Institutional Buildings

Think About It

6.8 Reclamation and recycling are saving water throughout the world

Santa Rosa, California

tertiary treatment

RECLAMATION IS CENTRAL TO WATER MANAGEMENT IN SANTA ROSA, CALIFORNIA

Windhoek, Namibia

Industrial Water Reclamation

Think About It

6.9 Desalination taps Earth’s largest reservoir of water

DESALINATION BY DISTILLATION: EVAPORATION AND CONDENSATION OF WATER

OSMOSIS MOVES WATER ACROSS A SELECTIVELY PERMEABLE MEMBRANE

The Tampa Bay Desalination Plant

Think About It

6.10 Conservation and restoration can protect aquatic ecosystems and biodiversity

Restoring Floods to the Colorado River

Restoring River and Wetland Structure

KISSIMMEE RIVER STRUCTURE: LOST AND RESTORED

Think About It

6.8-6.10 Solutions: Summary

Central Question: How can we meet human needs for freshwater, while avoiding or reducing environmental impact?

6.1–6.2 Science

6.3–6.6 Issues

Water Resources and You

☐ Learn about water supply, consumption, and issues in your community.

□ Actively support water conservation programs in your community.

☐ Commit yourself to water conservation in your daily life.

☐ Become involved in river or wetland restoration.

6.7–6.10 Solutions

Answer the Central Question:

Chapter 6

Review Questions

Critical Analysis

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