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6.5: Water Distribution

Difficulty Level: Basic Created by: CK-12
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What do you have to do to get water?

In the developed world, we just open a tap. Clean water is available all the time. In many developing regions women have to walk long distance to get clean water. Sometimes there isn't a source of clean water and they just get what they can find. We take water for granted in the developed world.

Water Problems: Not Enough Water

Most Americans have plenty of fresh, clean water. But many people around the world do not. In fact, water scarcity is the world’s most serious resource problem. How can that be? Water is almost everywhere. But much of it is unusable. What is usable is not always where it is needed.

Where Is All the Water?

One problem is that only a tiny fraction of Earth’s water is fresh, liquid water that people can use. More than 97 percent of Earth’s water is salt water in the oceans. Just 3 percent is freshwater. Most of the freshwater is frozen in ice sheets, icebergs, and glaciers (see Figure below ).

Boat sailing near St. Raphael glacier, in Southern Chile

This glacier in Southern Chile stores a lot of frozen freshwater.

Rainfall and the Water Supply

Rainfall varies around the globe. About 40 percent of the land gets very little rain. About the same percentage of the world’s people don’t have enough water. You can compare global rainfall with the worldwide freshwater supply in the Figure below . Drier climates generally have less water for people to use. In some places, people may have less water available to them for an entire year than many Americans use in a single day! How much water is there where you live?

Rainfall is a major factor affecting the water supply. Compare rainfall and the water supply in your part of the world.

Wealth and the Water Supply

Richer nations can drill deep wells, build large dams or supply people with water in other ways. In these countries, just about everyone has access to clean running water in their homes. Water is cheap and easy to get in these countries. It’s no surprise that these people also use the most water. In poorer nations, there is little money to develop water supplies. These people get their water where they can.

Water Shortages

Water shortages are common in much of the world. People are most likely to run short of water during droughts. A drought is a period of unusually low rainfall. Human actions have increased how often droughts occur. One way people can help to bring on drought is by cutting down trees. Trees add a lot of water vapor to the air. With fewer trees, the air is drier and droughts are more common.

We already use six times as much water today as we did a hundred years ago. As the number of people rises, our need for water will grow. By the year 2025, only half the world’s people will have enough clean water. Water is such a vital resource that serious water shortages may cause other problems.

  • Crops and livestock may die, so people will have less food available.
  • Other uses of water, such as industry, may have to stop. This reduces the jobs people can get and the products they can buy.
  • People and nations may fight over water resources.
  • In extreme cases, people may die from lack of water.

Vocabulary

  • drought : A long period of lower than normal rainfall for a particular region.

Summary

  • Fresh water is not evenly distributed across the planet.
  • Many of the world's people live without access to enough clean water. That percentage is likely to increase as populations grow.
  • During a drought, life may become very hard for many people.

Practice

Use this resource to answer the questions that follow.

Water Scarcity at http://www.youtube.com/watch?v=XGgYTcPzexE (3:27)

  1. What is water scarcity?
  2. Why do people take water for granted?
  3. How much freshwater is there on Earth?
  4. How many people do not have access to clean water?
  5. What will occur by 2025?
  6. What is physical water scarcity? Where does this occur?
  7. What is economic water scarcity? Where does this occur?

Review

  1. How is Earth's water distributed?
  2. How do wealthier nations deal with water problems? How do poorer nations deal with water problems?
  3. What is a drought? What can happen during a drought?

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Description

Difficulty Level:

Basic

Grades:

6 , 7

Date Created:

Jan 04, 2013

Last Modified:

Aug 24, 2014
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