Chasing Water Footprints


By Christina Phillis

The T-shirt you wear, the paper you write on and the food you eat could not have been made without water. T-shirts don't grow on trees, so why is water needed to make them? Think about the cotton needed to make the T-shirt. Did you know that it takes 713 gallons of water to grow the cotton that makes one T-shirt?

Scientists measure the amount of water being used to produce different goods around the world by dividing the Earth's surface by river basins. A river basin is the portion of land drained by a river and its many streams and creeks that flow downhill into one another. The next time you enjoy a Snickers you can thank the Volta River Basin. Located in West Africa, it is responsible for 10 percent of the water used to produce chocolate eaten in the United States.

Conservation Efforts

The fresh water used in agriculture and the production of goods is in high demand. Fresh water only makes up three percent of all the water on Earth. The other 97 percent of water is salt water found in oceans. While the amount of fresh water available stays the same, the population on Earth (more than seven billion people) keeps getting bigger. The need for fresh water continues to increase along with it.

There are different ways to reduce the world's water footprint, or the amount of water used. Farmers can reduce their water footprint by using drip irrigation, which works by delivering water directly to the roots of plants. This reduces the amount of water that evaporates or is absorbed into the air, meaning less water is lost or consumed.

Another way that people can conserve water locally is by buying goods that don't need as much water to produce. It takes 1,799 gallons of water to make one pound of beef. In contrast, one pound of chicken only needs 468 gallons.

Agriculture and industry not only contribute to the consumption of water, but also to its pollution. Fertilizer from farms in the Mississippi River Basin flows through different waterways until it gets to the Gulf of Mexico. Chemicals from this run-off fertilizer, such as nitrogen, result in the "dead zone," an area of low oxygen that is harmful to fish and aquatic life.

So the next time you wash your T-shirt, make sure it's with a full load. You never know what effect your water footprint can have.

Classroom Discussion

  • What factors contribute to your water footprint?
  • What can you do to conserve the amount of water you consume?