Earth’s Fresh Water
The water on Earth that is used by people and organisms on land is fresh water. Only about three percent of the water on Earth is fresh water. Most of the Earth’s fresh water is unavailable for use by people and other organisms. It is frozen in areas around the North and South Poles and in glaciers and icebergs. This leaves less than 0.5 percent of fresh water available to people and other organisms.
The fresh water that is available flows from high in the mountains down streams and waterfalls. It flows through rivers into and out of lakes. As it moves over the Earth’s surface, some water seeps into the ground. It gathers in the spaces in rocks and soil as groundwater. The groundwater can be extracted by digging wells.
A dam is a substantial structure, typically composed of concrete, earth, or rock, that is constructed across a river to control and store water. The area where water collects behind the dam, known as a reservoir, acts as a large lake.
Dams serve a variety of functions. They are built to secure water supplies, ensuring there’s enough water for drinking or for irrigating farmlands. Many dams are designed to generate electricity – these are often referred to as hydroelectric dams. Dams also play a critical role in flood control. They hold back water, releasing it slowly and thereby helping to prevent floods downstream. The reservoirs created by dams often become popular sites for recreational activities, such as boating, fishing, and swimming.
Related Printables.
Earth’s Landforms
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Comprehension – Earth’s Landforms
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Local Land and Water Features
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Modeling the Earth’s Features
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The Ocean
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Earth’s Fresh Water
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Using Maps
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Map Features
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Map Patterns in the United States
![](https://ngscience.com/wp-content/uploads/4-NGScience-Mapping-the-Earths-Surface_09.small_.jpg)
Comprehension – Ocean Patterns
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Observing Ocean Patterns
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Review – Mapping the Earth’s Surface
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Assessment Pack
• printable PDF
• answer key
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