Seen from space, Earth is the “blue planet,” dominated by water.

In fact, water covers nearly 70 percent of our planet.

But, while our water resources may appear limitless, in reality they are very small.

Most of Earth’s water is in the oceans.

This saltwater isn’t drinkable by humans, unless it is desalinated, a costly process.

Much of the remaining freshwater is also out of our reach—most of it is frozen in permanent glaciers and icecaps.

Amazingly, on a planet covered in water, less than 1 percent of it is available for us to drink.

Water on the Move

Water is constantly on the move.

In an endless cycle fuelled by the Sun, water moves from the surface of our planet, into the atmosphere, and back again to Earth as rain or snow.

This water cycle refills Earth’s lakes, rivers, and aquifers.

It provides critical freshwater on which billions of people depend.

Water Variability

The water cycle can be uneven and unreliable.

Some seasons may provide plentiful water resources, but streams run dry at other times.

Nature’s variability can make relying on surface water sources a very risky proposition—particularly in Earth’s more arid regions.

In India, the traditional practice of rainwater harvesting is being used on rooftops in rural schools to boost water supply.

This practice helps communities manage the annual variability of a single wet monsoon season in a mostly dry calendar year.

Ground Water Renewability

Groundwater reservoirs called aquifers hold the majority of accessible fresh water that can be used for drinking.

Many aquifers refill naturally, as water at the surface seeps into the ground after heavy rainfalls.

But other aquifers in arid climates are not being recharged.

The Nubian aquifer in northern Africa is one such aquifer.

The Great Man Made River Project in Libya is tapping into this resource to bring water to arid communities.

The aquifer was filled tens of thousands of years ago, during the last ice age.

Because of the area’s dry climate, the aquifer can no longer recharge.

Which means, when this water’s gone, it’s gone for good.

Shared Resources

Water use and access is an ancient source of human conflict, and water supplies are becoming more scarce as Earth’s population grows.

The Nile River, which is shared among 10 independent nations, is a good example of a shared resource.

This important resource must be managed on an international level to avert conflict and benefit the people who rely on it.

Fortunately all natural water sources, on and below the surface, can be managed to ease variability and protect the quantity and quality of water sources.

Protecting and conserving this precious resource begins at the source.

Only by understanding where our water comes from can we manage it—to make the most of every available drop.