Tag Archives: surface water

Data visualization, Water, Water supply

Drop on the planet: 3 visualizations of Earth’s most precious natural resource

Scarcity of freshwater is a defining feature of the American West, and planet Earth.

Nearly 97% of the world’s H2O is in the oceans. More than two-thirds of the globe’s freshwater is frozen in glaciers and polar ice caps.

Below are a trio of graphics to visualize water on Earth. I’ve found these slides useful for providing context in water-related presentations.

1) The world’s water: drop on a planet

About 70% of the planet’s surface area is covered by water, but the amount is tiny when compared to the Earth’s total volume. The illustration below shows that if you collected all of the planet’s water into a single sphere, it would be 860 miles across. Situated to the right is a 170-mile-wide ball over Kentucky that represents all the fresh liquid water found in the ground, lakes, swamps, and rivers. That miniscule 35-mile-wide dot over Georgia is all the freshwater in lakes and rivers.

Water on Earth graphic
Source: U.S. Geological Survey

2) The water cycle: a closed loop

The diagram below illustrates the water cycle and a critical point: water on Earth is essentially a finite resource and the system is basically a closed one. If you want to be a stickler, it’s not a 100% closed system since there’s a bit of entry and leakage via comets depositing ice and water vapor escaping to space. This graphic also doesn’t show volcanoes emitting steam or water lost to faults on the ocean bed. But the basic point remains: we can reuse water, convert the sea into a potable supply, even try to coax the sky into precipitating with cloud seeding, but we can’t manufacture new water.

U.S. Geological Survey water cycle
Source: U.S. Geological Survey

3) Breaking down the types of water

The graphic below shows that freshwater comprises just 2.5% of the Earth’s total water supply and 69% of that freshwater is locked up in glaciers and icecaps (at least for now). Most of the remaining freshwater is found below our feet as groundwater. Sometimes this subterranean supply is relatively easy to access, but in other locations it may be too deep or costly to extract. Fresh surface water is a rare commodity on this planet. Rivers, for example, account for just 0.006% of all freshwater and 0.0002% of all water found on Earth.
Distribution of water on Earth

We have more slides covering water issues, including supply, demand, quality, infrastructure, and climate change, in our water PowerPoint presentation.

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Groundwater, Surface water, Water, Water supply

Flow diagrams of U.S. and Western water use

Americans use an average of 410 billion gallons of water per day. Where does all that water come from and where does it go?

Flow diagrams from the Lawrence Livermore National Laboratory provide excellent summaries of the nation’s water use. These graphics, also known as Sankey diagrams, show how much we pump from groundwater aquifers, how many gallons of surface water we divert, and which economic sectors use the most water.

In this slide deck (download links at bottom of post), I’ve pulled together the flow diagrams for the 11 Western states, which show some interesting regional patterns in water use.

Flow diagrams of U.S. and Western water use from EcoWest on Vimeo.

Diagrams visualize commodity flows

Lawrence Livermore produces similar graphics for energy and carbon dioxide. In another post, I provide a little background on Sankey diagrams, which are a great tool for visualizing how a commodity flows through a system.

Data for the water diagrams come from the U.S. Geological Survey, which publishes a report every five years summarizing the nation’s water use (the latest year available is 2005).

The flow diagrams segment water sources into four main categories: fresh surface water, saline surface water, fresh groundwater, and saline (brackish) groundwater. Lawrence Livermore summarizes national-level water use this way:

Fresh surface-water, from lakes and rivers, is used at large scale in every sector of the economy. Saline surface water, primarily ocean water, is mostly used for once-through thermoelectric cooling, although some ocean water is used for industrial cooling and a small but growing amount of ocean water is being desalinated for public consumption. Significant quantities of fresh groundwater are used in irrigation and fresh groundwater plays an important role in both public supply as well as self-supplied domestic water consumption. Brackish groundwater is the most difficult water resource to use and is therefore primarily used in the mining sector and in power production (often in geothermal power plants).

Western states vary widely

The state-level slides reveal that water is managed very differently across the West, with some residents heavily dependent on surface water and others more reliant on groundwater. In Montana, Utah, and Wyoming, saline groundwater is an important source for mining and industry, while in Idaho and Oregon there’s a fair amount of fresh water devoted to aquaculture.

Across the region, the water delivered to homes and businesses is just a fraction of what’s devoted to growing crops. Consider the arid state of Arizona, where discussions about water tend to focus on the state’s growing cities. In reality, the graphic below (click to enlarge) shows that farming totally dominates water consumption in Arizona.

Arizona water flow

When examining these slides, it’s important to remember that the size of the rectangles and the connecting lines are not comparable from state to state. Instead, they show the proportions of surface water and groundwater that are directed to various uses within each state.

Lawrence Livermore also offers this caveat:

Water use data is notoriously hard to compile. Accounting policies vary between different water management districts and water use is not metered in the same way that higher-priced commodities are sold. Quantifying water use by location and sector requires substantial estimation.Water disposition is even more difficult to quantify. While the quality of wastewater discharge is measured regularly for environmental purposes, the total quantity of wastewater is not carefully monitored, especially when that wastewater already meets environmental regulations for discharge.

Despite these drawbacks, I’ve found these diagrams to be super-helpful in understanding Western and national water-use patterns. Once the U.S. Geological Survey releases data from the 2010 report, which isn’t expected until 2014, it’ll be interesting to see if there have been any significant shifts in water use.

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EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, follow us on Twitter, or like us on Facebook.