Tag Archives: water use

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.

Downloads

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.

Water, Water supply

Survey says: water bills are rising

In the West and around the nation, the price of water keeps going up.

Since 2010, Circle of Blue has been gathering water rate data in the 20 largest U.S. cities, plus 10 regionally representative cities. From 2011 to 2012, single-family residential water prices rose an average of 7.3 percent; since 2010, the increase is nearly 18 percent.

The graphics below show how water bills have changed in Western cities. One interesting feature of these charts is that they analyze water use under three different scenarios: low use (50 gallons per person daily), medium use (100 gallons per person daily), and high (150 gallons per person daily.) To promote conservation, many Western utilities have a progressive rate structure, which charges customers more per gallon if their use exceeds certain thresholds.

Mountain west water rates

Mountain Water PriceWest coast water rates WestCoastWaterPrice

On the national level, the price of water is rising at a pace much faster than the overall rate of inflation. The graphic below, from the Institute of Public Utilities at Michigan State University, compares the costs of various utilities and water/sewer bills really stand out.

Trends in utility prices

CPItrends Many Western utilities are searching for new (expensive) supplies to meet the rising demands of the growing customer base, putting upward pressure on rates. But the nation’s crumbling water works are perhaps an even bigger driver of the increasing costs, as Circle of Blue notes:

The upward trend for rates is an inherent feature of the water sector. Compared with other utilities, water departments require significantly more assets — pumps, pipes, and plants — to generate revenue. All of that hardware is expensive to maintain, and, as the fountain of water main breaks across the U.S. attests, a good portion of this infrastructure has come to the end of its effective life. The American Water Works Association recently estimated that replacing the nation’s pipes alone will cost $US 1 trillion over the next 25 years. Most of this will come from ratepayers, who pay as much as 99 percent of all money that is spent on water supply systems, according to the U.S. Conference of Mayors

Rising prices are generally portrayed as a bad thing in the media, and I’d just as soon spend my money on something other than my monthly water bill, but the bright side to increasing prices is that it can encourage more efficient water use.

For more on these issues, check out our water deck, which includes some slides on the price of water and the sorry state of our nation’s water infrastructure.

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.