Moving Water Across California

To overcome water scarcity in the southern part of the state and to increase agricultural production through the twentieth century, an intricate water infrastructure grew across the state of California. Different federal, state, and municipal agencies built and maintain a network of reservoirs, aqueducts, canals, pumping stations, and power plants to transport water from water-rich to water-poor regions. For example, the State Water Project moves water from rivers in Northern California all the way to the San Diego Aqueduct under the supervision of the California Department of Water Resources. The total length of the pipeline infrastructure is about 1,100 kilometers (km) (700 miles), including the world's largest water pumps at the Edmondson Pumping Plant that lift water 600 meters (2,000 feet) over the Tehachapi Mountains.

The Dos Amigos Pumping Plant on the California Aqueduct lifts water coming from the north 36 m (118 feet) to flow by gravity 265 km (164 miles) south to the next pumping station. The State Water Project consumes approximately 3.7 kWh/m³ (14,000 kWh per million gallons) to transport water from the Sierra Nevada Mountains to San Diego.

Over 25 million people receive access to clean freshwater through this project, which consumes 5.1 terawatt-hours (TWh) each year, between 2% and 3% of the entire state’s electricity capacity.1Ronnie Cohen, Barry Nelson, and Gary Wolff, Energy Down The Drain: The Hidden Costs of California’s Water Supply (Oakland: National Resources Defense Council and Pacific Institute, 2004). The State Water Project shares many facilities with the Central Valley Project, which alone has about 800 km (500 miles) of canals. Transporting the water consumes 1 TWh annually, but 11 hydroelectric power plants in the system harness electricity from the snowmelt. Additionally, the Metropolitan Water District of Southern California operates the Colorado River Aqueduct, which transports water from Lake Havasu on the Arizona-California border to the Santa Ana Mountains for the Los Angeles and San Diego metropolitan areas.

This map from the Public Policy Institute of California (PPIC) shows how the state’s elaborate network of conveyance and storage infrastructure is controlled by federal, state, and local agencies. Download the entire publication for free.

Although many people benefit from the improved infrastructure, the projects remain a source of contention within California. For example, the Central Valley Project ended salmon migration in the Sacramento, American, and Stanislaus Rivers.2John Williams, “Appendix A: Major Salmon Streams,” San Francisco Estuary and Watershed Science 4 (2006). Also, many agricultural operations made possible by irrigation increase stress on the already strained system. For example, tree nut production consumes 4 liters (1.1 gallons) per nut grown.3Erin Brodwin and Samantha Lee, “Chart shows how some of your favorite foods could be making California's drought worse,” Business Insider, April 8, 2015, accessed August 30, 2016, link.

The documentary Cadillac Desert offers a deeper look at the history of water in California and the State Water Project.

Image Credits: Tom/; Aaron Kohr/


Though abundant globally, water is often out of reach. When water is far away, energy is used to transport it. And, because of its density—water weighs 1,000 kg/m3 (8.34 pounds per gallon)—the energy required to raise water is significant. The total energy needed for pumping water depends on the height to which the water is raised, the rate at which it is raised, pipe diameter, friction, and other factors. Whether raising water from a well or pumping water over a mountain, the total energy required must overcome the force of gravity exerted on that volume of water.

The ancient Egyptians used Archimedes’ screw, which is a clever device that converts the manual turning of a screw into a process that elevates water. The tight coil of connected blades raises water as long as it is continually operated. Its invention is attributed to Archimedes in the third century BCE, but might have been in use earlier. Thousands of years later, modern water-lifting stations at amusement parks, water treatment plants, and elsewhere still make use of the design.

Schlitterbahn Waterpark in New Braunfels, Texas, uses an Archimedes’ screw to lift 36,000 gallons (136 m3) of water per minute to power The Falls, billed as “the world’s longest tubing adventure.”1John Boyd, “35 fun facts about Schlitterbahn on its 35th anniversary,” My San Antonio, March 5, 2014, accessed August 29, 2016, link; and Winter Prosapio, “Schlitterbahn New Braunfels Waterpark Fact Sheet 2016,” Schlitterbahn Newsroom, February 18, 2015, accessed August 29, 2016, link.

A medium-sized U.S. city with one million residents might need 570 million liters (150 million gallons) of water per day. Raising that water from surface sources to elevated water treatment plants over a height of 100 meters requires a little more than 6 megawatts (MW) of pumping power. Massive wind turbines generate approximately 1 MW each, so the city would need 6 turbines running at full capacity exclusively for pumping water to the treatment and storage facility at the top of the hill, after which it can flow downhill to customers. The energy intensity of pumping is one of the reasons why people prefer shallow wells and surface water sources. Deeper, dirtier sources require even more energy and are usually only deployed when less energy-intensive options are available.

Using local surface water for agricultural applications requires less energy than transporting water from the Colorado River Aqueduct for treatment and distribution to residences where the water is subsequently heated.

Image Credits: Peter Turner Photography/

Modern Thermodynamics

The field of thermodynamics is the underlying science of energy. The word thermodynamics itself reveals its component parts.

The components of the word thermodynamics are derived from the Greek words θέρμη therme, meaning “heat,” and δύναμις dynamis, meaning “power.” The term thermo-dynamic was first used in January 1849 by William Thomson, later Lord Kelvin, in the phrase “a perfect thermo-dynamic engine” to describe Sadi Carnot’s heat engine.

Energy contained in fuels such as coal, oil, wood, or gas can be converted into useful functions such as mechanical work for moving a car or crushing rock and can be used for thermal activities such as warming and cooking. But, before that energy in the fuels can be harnessed, it must be transformed. These transformations are governed by the laws of thermodynamics. While these fuels enable useful services, they also cause pollution and waste.

The laws of thermodynamics provide the key scientific principles or physical laws by which society harnesses (and wastes) energy. The science of thermodynamics developed in the 1800s from the desire to increase the performance of early steam engines. These engines were increasingly valuable in Britain just after the Industrial Revolution because they provided mechanical power at factories and mills.

Iron and Coal, 1855–60, by William Bell Scott illustrates the rise of coal and iron working in the Industrial Revolution and the heavy engineering projects they made possible.

The development of more efficient steam engines benefited from the emergence of the scientific method. Inventors and scientists tested hypotheses against empirical evidence, leading to a truly scientific understanding of the phenomena they witnessed. As factory workers and inventors developed iterative models of early engines, early scientists, such as Thompson, Carnot, Watt, and Joule, began to generalize evidence from the field into theory, producing the laws of thermodynamics.

Both scientists and engineers contribute to the world of human knowledge, but in different ways. Scientists use the scientific method to make testable explanations and predictions about the world. Engineers use the engineering design process to create solutions to problems.

As prominent science historian Bruce Hunt noted, it is not clear who helped whom the most. While the modern paradigm for innovation suggests that discoveries in the lab lead to better engineering design in the field, the historical relationship of thermodynamics and the steam engine may be reversed. Rather than going from fundamental science to a better engine, the tinkerers inventing and improving engines in mines and factories advanced the science of thermodynamics more than the theoretical scientists improved the engines. Engineers converted heat into motion before scientific theory could explain the phenomenon.

Image Credits: Baptist/; Jeffrey M. Phillips/Webber Energy Group.

A New Definition of Humanity

Conventionally, anthropologists defined humans by their toolmaking.1M.E. Webber, “Redefining Humanity Through Energy Use,” Earth Magazine, March 2010. However, Jane Goodall observed chimpanzees in the wild for decades and discovered that chimpanzees also make and use tools. They use leaves as makeshift bowls to scoop water and stones and other found objects to make noise to establish dominance within another group of chimpanzees. They strip sticks of leaves and thorns, leaving a smooth stem to extract termites from mounds. Jane Goodall’s work redefined humankind because the definition of man as tool-user no longer held.2Jane Goodall: The Woman Who Redefined Man. Dale Peterson. Houghton Mifflin, Boston, 2006.

Dr Jane Goodall poses for a photo at Taronga Zoo in Sydney, Australia. Goodall, the world renowned primatologist, has acknowledged the breeding and work research carried out by the Chimpanzee Group at Taronga Zoo over recent years. (Photo by Craig Abraham/Getty Images)

Today, manipulating forms of energy distinguishes humans from other species. Though all species benefit from the natural conversion of radiant energy (sunlight) into chemical energy through photosynthesis, humans are the only species that deliberately converts energy from one form to another—for example, converting chemical energy (fuels) to thermal energy (heat) or mechanical energy (motion). Thus, a new definition of humanity emerges; humans intentionally manipulate energy, but other species do not.

Image Credits: Vincent St. Thomas/

Defining Energy and Power

Energy is the fundamental driver of most of the processes we care about. It drives photosynthesis to make plants grow, it powers cellular functions, and its modern forms make today’s societies different from those of antiquity.

Energy is the ability to do work, where work is defined as exerting force over a distance.

Work = Force × Distance

1 newton is the force needed to accelerate 1 kg at 1 m/s2.
1 joule is the amount of energy required to apply a force of 1 newton for 1 meter.

Lifting a rock and pushing a wheelbarrow are examples of work. While energy can be evaluated, predicted, and controlled, it remains an abstract concept that is hard to define, touch, or describe. Despite the fact that energy surrounds us and is embedded within us in many ways, energy remains indescribable. Even the great Nobel laureate Richard Feynman, who worked deeply with quantum mechanics and electrodynamics, pointed out the mysteries of energy.

“We have no knowledge of what energy is … It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.”—Richard Feynman

Power is closely related to but different from energy. While energy is a quantity, power is a rate. It is the rate at which energy is produced, moved, or consumed per unit of time, or work per unit of time.

Power = Work ÷ Time

1 watt is the power needed to accelerate 1 kg at 1 m/s2 for 1 meter in 1 second.

Power indicates the rate at which work is performed or how quickly energy is consumed.

As a scientist, engineer or thermodynamicist, one can describe transformations of energy more easily than the fundamental nature of energy itself. Ambiguity is one of energy’s many challenges. Thermodynamic definitions of energy include “something we use to predict and explain how things happen.” One can teach what energy does. Societies can harness it, convert it, manipulate it, and clean up its resources, but no one can touch it or see it. Yet the evidence of its existence is all around us, omnipresent—and maybe omniscient, too, if you include the information contained within energy—like a mysterious force.

Image Credits: Pete Saloutos/.