The world’s population has surpassed seven billion, and that means more people rely on a finite amount of freshwater. The majority of that water is used in agriculture, and in this interactive we take a look at the impact of some of the most important crops produced for U.S. consumption.

In order to better understand water use and availability trends, scientists divide the Earth’s surface into river basins. This feature examines some of the river basins that are the most important from an agricultural perspective. In each basin, the primary source of water is precipitation. Rain and snow feeds the river and its tributaries, as well as groundwater, ponds, and lakes. Precipitation also adds moisture to the soil, and crops take up the moisture through their roots.

Most crops around the world are grown using only the soil moisture provided by rainfall. When this moisture is insufficient, farmers apply more water through irrigation. Some rain or irrigation water evaporates without benefiting the plant, while some transpires through the plant's tissues during photosynthesis and returns to the atmosphere. Water transformed into vapor in either of these ways is not available for use again in that local area, so in practical terms, it is lost or "consumed."

Different crops have different water needs, which vary with the climate in which they’re grown. Scientists at the University of Twente in the Netherlands have used modeling techniques to estimate the amount of water consumed by the various crops grown in river basins around the world. These are the data we use in this feature.

Fortunately, there are things farmers can do to reduce water consumption. Instead of flooding fields or sprinkling, they can use drip irrigation, which cuts evaporation losses by delivering water directly to the roots of plants. Such techniques are particularly important in dry regions, where heavy water consumption is depleting rivers and even causing some to dry up for portions of the year, as is currently the case with the Colorado, the Indus, the Murray, the Rio Grande, and others.

Learn more about global water footprints from the Water Footprint Network and about rivers and watersheds from The Nature Conservancy. Find out how much water is consumed to make everyday things and try our water footprint calculator to get a snapshot of your own consumption. Also check out our water wiz puzzle for kids.

More About Freshwater

  • freshwater-101-promo-160x120.jpg

    A Freshwater Story Interactive

    Earth is a water wealthy planet, but only a tiny portion of its water is available to support people and aquatic species. Learn more about how much freshwater there is, and where it's found.

  • Photo: Girls playing in the Dead Sea

    Parting the Waters Photo Gallery

    Water has always been precious in this arid region, but a six-year drought and expanding population conspire to make it a fresh source of conflict among the Israelis, Palestinians, and Jordanians vying for the river's life-giving supply.

  • Photo: People waiting for water truck

    Drinking Water and Sanitation Quiz

    For much of the world, drinking a glass of water is not as easy as filling up at a water cooler or even the kitchen sink.

  • Photo: searching streams for fish

    Silent Streams Photo Gallery

    Freshwater animals are vanishing faster than those on land or at sea. But captive-breeding programs hold out hope.

In the Field

Help Save the Colorado River

You can help restore freshwater ecosystems by pledging to cut your water footprint. For every pledge, Change the Course will restore 1,000 gallons back to the Colorado River.

Freshwater Advocates

  • Picture of Peter McBride in Kenya

    Freshwater Hero: Pete McBride

    Pete is a photographer and visual storyteller with an emphasis on freshwater conservation.

  • sandra new headshot.jpg

    Sandra Postel

    Sandra is a leading authority on international freshwater issues and is spearheading our global freshwater efforts.

  • Photo: Osvel Hinojosa Huerta

    Osvel Hinojosa Huerta

    For more than 15 years, Osvel Hinojosa Huerta has been resurrecting Mexico's Colorado River Delta wetlands.

For More Inspiration »

Water Blog Posts

See More »

Explore Freshwater

Change the Course logoChange the Course: Help Save the Colorado River