Freshwater Conservationist: Sandra Postel

Freshwater Conservationist: Sandra Postel

Profile of Sandra Postel, freshwater conservationist and National Geographic Freshwater Fellow.


5 - 12+


Biology, Ecology, Health, Earth Science

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Sandra studies the relationship between water resources and agriculture, industry, health, and security. She shares this information with the public through writing and lectures.

As founder of the Global Water Policy Project and lead expert for National Geographic’s Freshwater Initiative, her goal is to promote the conservation and sustainable use of Earth’s freshwater resources.


Sandra says she grew up in New York as a “Long Island beach kid.” She was always aware of the “solace, peace, and balance” offered by the natural world, especially aquatic environments of wetlands and rivers.

In college, Sandra studied both the natural and human environments and how they interact with each other. She earned her undergraduate degrees in geology and political science from Wittenberg University in Springfield, Ohio. Sandra went on to earn an M.E.M. degree from Duke University in Durham, North Carolina. (M.E.M. stands for “Master of Engineering Management.” M.E.M. degrees combine the technical and scientific aspects of engineering with business and economic aspects of management.)


“Learning about people, developing solutions to big problems.”


“So much to do, so little time!”


“The study of place, including social and ecological systems . . . the whole package! . . . I look at the world through a water lens, so geography also incorporates how water is being affected in a certain place.”


Before starting work on a project, Sandra considers an area’s “geography of water”: the amount of water in the area’s aquifer or basin, the population, and the agricultural use of water.

The geography of water helps Sandra determine an area’s water stress. Water stress is the situation when a community is “using more water than nature made available.”

Communities can stress their water supply in many different ways: “Irrigation depletes rivers; populations rise, requiring more safe drinking water; the amount of water needed to supply food to a population—agriculture—grows,” Sandra explains.

Sandra first became aware of the concept of water stress after reading Swedish hydrologist Malin Falkenmark’s book Water for a Starving World. This groundbreaking work linked water use, food, and population.

As Sandra began to understand water stress, she realized it “affects everything,” from a community’s development to its political security. “So many great civilizations developed alongside rivers and lakes,” she says, pointing to the ancient civilizations of Ur (between the Tigris and Euphrates rivers), Egypt (which developed on the Nile), and the Indus River Valley.

Today, Sandra points out, more than 200 rivers are shared between two or more nations. Dams and other river management techniques implemented by nations upstream have a huge impact on nations downstream. The Tigris and Euphrates rivers have their sources in Turkey, for example, but their basins are in Iraq, Kuwait, Saudi Arabia, and Syria. River management from Turkey would impact the freshwater available to these countries for drinking, hygiene, industry, and transportation.

Water management has become part of many nations’ foreign policy. Sandra points to the Mekong River Commission. The headwaters of the Mekong River are in China, although the basin is nearly 800,000 square kilometers (308,881 square miles) and includes the nations of Myanmar, Cambodia, Laos, Thailand, and Vietnam. Many governments are members of the Mekong River Commission, which promotes sustainable development of the water supply. China is not a member.


“Spend time outdoors. Find out which science you’re interested in, find your niche.”

Sandra also recommends at least some engineering classes. “When you find out how things work, you find out how to change to make it better.”


“Know your watershed!”

Knowing where your water comes from creates a “connection to a place in nature, and what’s happening in nature . . . and how that affects you.”

Sandra also encourages everyone to be aware of their water footprint. There are four parts of a water footprint: household use, diet, energy, and materials. Household use includes water used for showering and washing clothes and dishes. Diet is the food we eat, including drinking water and the water used to grow foods, such as corn and tomatoes, and raise animals, such as cattle and pigs. Energy use includes the water used to build and operate cars, buses, and planes. Materials include the water used to make clothing, furniture, and electronics.

Calculate your water footprint here.

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National Geographic Society
Last Updated

March 1, 2024

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