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Environmental Science
Grade 7-12
Freshwater Resources & Water Scarcity Cheat Sheet
A printable reference covering freshwater distribution, the water cycle, groundwater, withdrawals, scarcity causes, conservation, and water footprints for grades 7-12.
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Freshwater resources include the water people use for drinking, farming, sanitation, energy, and ecosystems. This topic explains where freshwater is found, how it moves through the water cycle, and why usable water is limited. Students need this cheat sheet to connect Earth systems with human choices and understand why water scarcity affects communities differently. It also helps students compare conservation methods and interpret water use data.
Key Facts
- About 97% of Earth's water is salt water, and only about 3% is freshwater.
- Most freshwater is locked in glaciers and ice caps, so less than 1% of Earth's total water is easily available in lakes, rivers, and shallow groundwater.
- The water cycle moves water through evaporation, condensation, precipitation, infiltration, runoff, and transpiration.
- Groundwater is stored in aquifers, and recharge happens when water infiltrates soil and rock layers.
- Water withdrawal is the total amount of water taken from a source, while water consumption is the portion not returned quickly to the same source.
- Water scarcity can be physical, when water is naturally limited, or economic, when people lack infrastructure or money to access clean water.
- Per capita water use = total water use / population.
- A water footprint includes direct water use, such as showers, and indirect water use, such as water used to grow food or make products.
Vocabulary
- Freshwater
- Water with low salt content that can be used by living things and humans after little or reasonable treatment.
- Aquifer
- An underground layer of rock, sand, or gravel that stores and transmits groundwater.
- Recharge
- The process by which water enters an aquifer, usually by soaking into the ground after rain or snowmelt.
- Water scarcity
- A condition in which available clean water is not enough to meet the needs of people, agriculture, industry, and ecosystems.
- Runoff
- Water that flows over land into streams, rivers, lakes, or oceans instead of soaking into the ground.
- Water footprint
- The total amount of freshwater used directly and indirectly to support a person, product, community, or activity.
Common Mistakes to Avoid
- Thinking all freshwater is easy to use, which is wrong because much of it is frozen in ice or stored deep underground.
- Confusing water withdrawal with water consumption, which is wrong because withdrawn water may be returned while consumed water is not quickly available again.
- Assuming water scarcity only happens in deserts, which is wrong because pollution, overuse, poor infrastructure, and drought can create scarcity in many climates.
- Ignoring groundwater recharge rates, which is wrong because pumping aquifers faster than they refill can lower water tables and dry wells.
- Treating conservation as only shorter showers, which is incomplete because food choices, irrigation methods, leak repair, and industry practices often save much larger amounts of water.
Practice Questions
- 1 A town uses 12,000,000 liters of water per day and has 40,000 people. What is the per capita water use in liters per person per day?
- 2 A farm withdraws 5,000 cubic meters of water for irrigation and 3,500 cubic meters evaporate or are taken up by crops. How much water is consumed?
- 3 If Earth has 100 units of total water and about 3 units are freshwater, about how many units are salt water?
- 4 Explain why two cities with the same annual rainfall might have very different levels of water scarcity.