This infographic produced by the United States Geological Survey makes it easy to visualize why water is not to be squandered.

Image: USGS.gov

It displays just how much of the Earth’s water is available for use. It’s not as much as you’d think when you look at it in relationship to the size of the Earth.

The largest of three spheres represents all the water on Earth, salt and fresh. The second largest represents just freshwater.

Think that’s small? Consider the tiny little speck just above Florida. It represents the volume of freshwater actually available as surface water. According to the US Geological Survey, 80 percent of the water used by Americans in 2005 came from surface water.

Now consider a scant 20 percent of that tiny amount. That would represent the Great Lakes

The key to deciphering the graphic is to think in terms of volume (what can be measured in a cup). Sure, 70 percent the Earth’s surface is covered with water; but when we collect that water into a pool and compare it to the land left behind, it becomes obvious that Earth is mostly a large rock covered with a superficial layer of water.

Superficial is a relative term. If you dove into the largest sphere like it was a pool, you’d have to swim 860 miles to get from one end to the other; that’s a big pool. Unfortunately, it’s also a salty one.

The pool of available surface water – the one we need to drink from, and shower in and grow crops with – shrinks in comparison. It doesn’t quite reach 35 miles long.

A recent Great Lakes Echo feature, “How Much of the World’s Water is Drinkable?”, notes that most of the Earth’s freshwater reserves are unavailable for easy use because large volumes are either frozen in glaciers or buried below the Earth’s surface.
“Our freshwater, our rivers and our lakes, really make up less than 0.0006%, or something of that nature, so we definitely have to think about protection of our freshwater system,” said Joan B. Rose, the director of the Center for Water Sciences at Michigan State University.

Because of the scarcity, processes are developing to make salt water fresh.

“With new technology, we’re actually using membranes and a process called desalination to create drinking water from the ocean,” said Rose.

The US Geological Survey has more in-depth data, graphs and quizzes about surface water and groundwater.