• 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 (Burma), 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 includes the water used to make clothing, furniture, and electronics.

    Calculate your water footprint here.

    Freshwater Conservationist: Sandra Postel
    Sandra Postel is a freshwater conservationist.
  • Term Part of Speech Definition Encyclopedic Entry
    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    ancient Adjective

    very old.

    aquatic Adjective

    having to do with water.

    aquifer Noun

    an underground layer of rock or earth which holds groundwater.

    Encyclopedic Entry: aquifer
    aspect Noun

    view or interpretation.

    basin Noun

    a dip or depression in the surface of the land or ocean floor.

    Encyclopedic Entry: basin
    beach Noun

    narrow strip of land that lies along a body of water.

    Encyclopedic Entry: beach
    cattle Noun

    cows and oxen.

    civilization Noun

    complex way of life that developed as humans began to develop urban settlements.

    Encyclopedic Entry: Key Components of Civilization
    concept Noun


    conservation Noun

    management of a natural resource to prevent exploitation, destruction, or neglect.

    Encyclopedic Entry: conservation
    dam Noun

    structure built across a river or other waterway to control the flow of water.

    deplete Verb

    to use up.

    development Noun

    construction or preparation of land for housing, industry, or agriculture.

    diet Noun

    foods eaten by a specific group of people or other organisms.

    Encyclopedic Entry: diet
    downstream Noun

    in the direction of a flow, toward its end.

    ecological Adjective

    having to do with the relationship between organisms and their environment.

    economic Adjective

    having to do with money.

    electronics Noun

    devices or tools that use electricity to work.

    energy Noun

    capacity to do work.

    engineering Noun

    the art and science of building, maintaining, moving, and demolishing structures.

    environment Noun

    conditions that surround and influence an organism or community.

    food Noun

    material, usually of plant or animal origin, that living organisms use to obtain nutrients.

    Encyclopedic Entry: food
    foreign policy Noun

    courses of action or thought that guide a nation's relationship with other nations.

    furniture Noun

    moveable articles, such as chairs and shelves, for furnishing a residence.

    geography Noun

    study of places and the relationships between people and their environments.

    Encyclopedic Entry: geography
    geology Noun

    study of the physical history of the Earth, its composition, its structure, and the processes that form and change it.

    government Noun

    system or order of a nation, state, or other political unit.

    groundbreaking Adjective

    innovative or pioneering.

    headwater Noun

    source of a river.

    health Noun

    condition of an organism's body and mind.

    hydrologist Noun

    person who studies the distribution, circulation, and properties of water.

    hygiene Noun

    science and methods of keeping clean and healthy.

    impact Noun

    meaning or effect.

    implement Verb

    to carry out plans.

    incorporate Verb

    to blend or bring together.

    industry Noun

    activity that produces goods and services.

    interact Verb

    to work with or meet.

    irrigation Noun

    watering land, usually for agriculture, by artificial means.

    Encyclopedic Entry: irrigation
    lens Noun

    transparent substance used to alter a person's vision.

    nation Noun

    political unit made of people who share a common territory.

    Encyclopedic Entry: nation
    niche Noun

    role and space of a species within an ecosystem.

    political science Noun

    study of political systems and the structure and conduct of governments.

    population Noun

    total number of people or organisms in a particular area.

    promote Verb

    to encourage or help.

    resource Noun

    available supply of materials, goods, or services. Resources can be natural or human.

    river Noun

    large stream of flowing fresh water.

    Encyclopedic Entry: river
    river management Noun

    the art and science of controlling the flow, path, and power of rivers.

    science Noun

    knowledge focused on facts based on observation, identification, description, investigation, and explanation.

    security Noun

    safety or stability.

    solace Noun

    something that gives comfort or respite.

    sustainable Adjective

    able to be continued at the same rate for a long period of time.

    sustainable development Noun

    human construction, growth, and consumption that can be maintained with minimal damage to the natural environment.

    technique Noun

    method of doing something.

    transportation Noun

    movement of people or goods from one place to another.

    undergraduate noun, adjective

    having to do with the first (bachelor's) degree earned in college or university.

    upstream Adjective

    toward an elevated part of a flow of fluid, or place where the fluid passed earlier.

    Ur Noun

    one of the earliest cities in the world, established as an urban center on the Euphrates River and the Persian Gulf as early as 3000 BCE.

    water Noun

    chemical compound that is necessary for all forms of life.

    water footprint Noun

    total volume of freshwater that is used to produce the goods and services consumed by the individual or community.

    watershed Noun

    entire river system or an area drained by a river and its tributaries.

    Encyclopedic Entry: watershed
    water stress Noun

    situation faced by a nation or community when the amount of available water is less than 1,700 cubic meters per person.

    wetland Noun

    area of land covered by shallow water or saturated by water.

    Encyclopedic Entry: wetland