Engineering Rome

Water Supply and Urban Development in Ancient Rome and Modern Cities

by Kiley Rempp

1. Introduction

A water supply system consists of “infrastructure that collects, treats, stores, and distributes water between water sources and consumers” (Adeosun, 2014). The most important component of a nation’s infrastructure is its water supply system. A population depends on a stable water supply to survive and flourish. A functioning water system is essential for a growing city, in particular Ancient Rome and modern day Seattle. A water system must adapt and grow along with the population it is serving. The shift towards a reliable water system was a defining moment in history for Rome and Seattle in times of chaos. This conversion led to the success of the Roman Empire and the Seattle, Washington. The engineering behind water flow to urban and rural areas in Ancient Rome and modern day cities has improved technologically, but some aspects have remained constant. Over 2,000 years, aqueduct engineering has evolved tremendously, yet they have constantly achieved the same goal. Aqueducts have been providing viable solutions to delivering water to areas that lack this precious resource. In fact, water is so crucial to a civilization that the first plan of action for sieging a city is cutting off its water source. When enemies attacked Ancient Rome, the aqueducts were easy targets and they were the first to be destroyed. Thousands of years later and the same method was used to attack the country of Libya. Today’s engineers should look towards Ancient Rome for engineering techniques, more specifically Roman aqueducts, as a guide to today’s water distribution problems. Regardless of the time period, nations are still motivated by the same principle: water is an essential resource for health and survival. Successful civilizations were and always will be dependent on having clean, reliable water sources. For 2,000 years, aqueducts have been providing viable solutions for bringing distant water to cities and towns. Today, the world faces new challenges like climate change. The world can learn from what worked well in ancient Rome and from their mistakes. Whether it be from the monuments that still remain or from the life they brought to the inhabitants of Rome, the aqueducts’ impacts are still felt across the world.

1.2 Capturing Roman Ideals

“2,000 years ago a city [Rome] provided drinkable and accessible water to its one million or so inhabitants. If ancient Rome could deliver the human right to water and in all of its cities and towns, why cannot we do the same in every town or city in the world in the 21st century?” (Prof. Grafton, 2017)  Studies have shown that the amount of water that aqueducts delivered to Rome was no more than the amount that modern cities use everyday. So why can’t modern cities also provide clean, public water? How have the ideals behind water distribution changed over time? How can we provide people with their right of water? With modern day technology, engineers can build water systems while incorporating these Roman ideals.

2. Water and Urban Development in Ancient Rome

2.1 A Brief History

Natural disasters have a way of reshaping civilizations. The Great Fire of 64 AD was a pivotal moment for the Roman Empire. On the night of July 18th, 64 AD, flames burned through the capitol city of Rome and burned for six days. Rome came back stronger than ever after this disaster. Rome was rebuilt from the ground up and its water system was improved so that the city would be prepared in the event of another fire. The Roman government made advancements toward a more stable, plentiful water supply. Another phenomenon that led to an improved water supply was Rome’s population explosion. There is still debate on the peak population of the Rome during the Roman Empire. It is difficult to accurately determine the populations of ancient civilizations like Ancient Rome. Estimates of Rome’s population since the Renaissance range from 500,000 to 14,000,000 people. Either way, Rome’s population was growing at an unprecedented rate and the city was headed for a serious water shortage. Thus, the first aqueduct, Aqua Appia, was commissioned in 312 BC.

2.2 Aqueduct Construction and Water Flow

Although the Romans did not invent the aqueduct, they perfected the process and raised the bar by the sheer quantity of aqueduct construction throughout the empire. They modeled aqueducts after Assyrian qanats, which are “tunnels driven into a hillside to tap an aquiferous stratum deep inside it” (Hodge, 2005). The qanat is positioned so that it is a elevated and with a slight downhill slope so that gravity forces the water down the hillside.

Figure 1: How gravity powers an aqueduct (Illustration by Approach Guides)

This technique is still used today in the Middle East, particularly Iran. It is simpler to understand the Romans’ techniques of tunneling and surveying because they are very similar to Assyrians’ techniques for building qanats. As for other Roman techniques, such as leveling and determining slope, we do not have physical evidence so we must rely on literary sources. Citizens in smaller Roman territories used many of these Assyrian qanats as important water sources because the aqueducts only served large cities, which will be discussed in detail in the Urban Distribution section. Once the aqueduct route had been determined, the construction began by digging vertical shafts into the ground until it reached the water (See Figure 4). From one shaft they would dig horizontally until they connected with the next shaft. This created one long channel connecting the water source, usually a spring, to the aqueduct. This process would continue until the underground tunnel reached the end of the hill. The channel was lined with bricks and concrete made with local materials.

Figure 2: Digging the tunnels and vertical shafts (Photo by National Geographic).
Figure 3: Chloe and Rebecca admiring the concrete lining of the Aqua Claudia (Photo by Kiley Rempp).

2.2.1 Measuring Volume of Flow

Roman pipes were measured in quinaria, which was “one and a quarter fingers” in diameter. The quinaria measurement causes the most problems in aqueduct studies. From an engineering standpoint, there are problems caused by this particular unit of measurement. It is impossible to measure a volume of water with only a linear measurement, the diameter of the pipe. The key element that’s missing is the rate of flow. It is perceived that Rome was very wasteful and used a lot more than necessary when it came to water usage. On the other hand, some argue that the Romans were actually very conservative with their water usage because the aqueducts did not supply nearly as much water as previously thought. According to the Commissioner of Water Supply of Ancient Rome, Frontinus, Rome’s aqueducts supplied the city with 200 million gallons of water per day (Morgan, 2006). But, Clemens Herschel, a well-known hydraulic engineer, questioned this large number. He decided to examine Frontinus’s claim with a modern engineering point of view. He wanted to know how much water the aqueducts actually supplied to ancient Rome. He believed that with more accurate information we could better compare the water supply of ancient Rome to that of today’s cities. Herschel’s main concern was the unit of measurement Frontinus used. Frontinus gives the water supply of each aqueduct in a unit called the “quinariae.” The quinaria is an adjustable unit and very unscientific, “A quinaria is the capacity of a pipe of “five quarter-fingers,” with a consequent diameter of 2.3 cm.” The quinaria tells us nothing about the daily flow of an aqueduct because flow also depends on the velocity of the current (Figure 4).

Figure 4: Measuring flow with a modern engineering equation (Photo by Physics LibreTexts).

But, there was no tried and true method for measuring velocity in ancient Rome so it’s not completely fair to blame Frontinus for leaving out this crucial information. Another important factor is hydraulic head (Figure 5), which Frontinus also leaves out. Elevation head is a measurement of the height of a static water column and the higher the water is above the ground, the more energy it has. The more energy water has, the faster it’s going to flow.

Figure 5: Visual example for aqueduct head loss (Photo from Roman Aqueducts and Water Supply, Hodge 2002).

It is theorized that Frontinus hoped the entire system variations in the head would cancel each other out. Herschel estimated that a quinaria was about 15,000 gallons a day. Frontinus recorded that the nine Roman aqueducts brought in 14,018 quinariae per day. This comes out to 200 millions gallons a day as a daily supply for Rome. Herschel did not believe this was accurate. He turned to investigations made by Colonel Blumenstihl, another hydraulic engineer. Blumenstihl measured the velocity of the Aqua Marcia, one of the longest of Rome’s aqueducts, to be 3.25 ft/sec at a point near its intake. Frontinus recorded that this intake point had 4,690 quinariae. Using this measurement, the volume flow rate calculates to 9,250 gallons per day. But, Herschel remarks that the actual value could have ranged from 2,500 to 9,000 gallons per day depending on where the quinariae was measured, so he uses an average of 6,000 gal/day. So, instead of 15,000 gallons a day, a quinaria was about 6,000 gallons a day. If we multiply 14,018 quinaria per day by this new value for 1 quinariae (6,000 gal/day) we calculate about 84 million gallons a day for the daily supply of Rome. This is a little less than half of Frontinus’s first estimation (200 million gal/day). Dividing this number by the population of Rome at its peak equates to 84 gallons a day per person. Today, the average person uses about 80-100 gallons a day. So, maybe Rome really did need nine aqueducts to support its population. As it turns out, they used the same amount per day that highly-populated U.S. cities use today (Figure 6).

Figure 6: In 1901, U.S. cities used more water per person than Ancient Rome (Photo by Professor Morgan, Harvard University).

Later on, in the Daily Supply section, we will see that this amount of 84 million gallons does not get delivered solely to the public. A good portion of it flows to the baths and private homes. Still, Roman aqueducts’ primary use was to serve Rome’s citizens with free drinking water. Roman citizens always had access to constantly flowing water and this is why Rome’s population kept growing. “Although contemporary engineering of water supply network and technology of water purification overcame the ancient Romans, in certain aspects this ancient example deserves to be followed” (Magdolna, 2005). Ancient Rome was supplied with the same amount of water as modern cities, yet supplied its citizens with sufficient amount of free water. Could modern U.S. cities follow this example?

2.3 Urban Distribution

2.3.1 Water’s Path throughout a City

Unlike today’s water systems, Rome’s aqueducts worked on the principle of constant supply. The water was rarely stored, rather it used all at once. Aqueducts supplied the public fountains, baths, and private houses. Once the water reached the edge of the city, it entered the castellum divisorium proper (Figure 7).

Figure 7: An above view of the castellum divisorium (bottom right) and a side view demonstrating the prioritized users (top right). (Photo from Roman Aqueducts and Water Supply, Hodge 2002).

This is the beginning of the distribution process throughout the city. Water enters the castellum divisorium from the single aqueduct pipe and exits through many separate branches. These separate branches go to many sub-castella, or water towers, where the water is then divided further into individual pipes serving public drinking fountains and private houses. Vitruvius explains the organization of the castellum, “a triple basin for receiving the discharge from the aqueduct should be attached to the castellum; and three equal pipes should bring water form the castellum to the three compartments of the basin, so arranged that when the two outside compartments overflow, it goes into the middle one. From the middle one, pipes go off to serve the public drinking fountains: the other two serve the baths and private homes” (Hodge, 1992). The three pipes with equal diameter guaranteed that the baths, public fountains, and private users had equal volumes of water reserved for them. Once this maximum volume was met for the baths and private users, the public fountains received all of the overflow water. But, what would happen in times of water shortage? There were no precautions taken to make sure the public fountains were the last to run dry. Figure 7 shows the middle compartment is much lower than the outer two. The middle compartment served the public drinking fountains so this guaranteed the citizens of Rome had first priority to meet their water needs. This fact emphasizes the Roman government’s commitment to public water works and the needs of every citizen, rich or poor. It is also important to note that citizens did not have to walk further than 50 meters to reach the nearest public fountain. Reference Figure 8 for a public fountain map.

Figure 8: Map of the close proximity of public water fountains (Photo from Roman Aqueducts and Water Supply, Hodge 2002).

There are two distinct layouts of pipes for the water distribution throughout a city. The first layout is one main pipe with branches off to each household. The second layout is one pipe for every household that leads directly back to the main castellum. The normal practice for Ancient Rome was the second layout, even though the first layout seems more logical and is standard practice today.

2.3.2 Daily Supply

The aqueducts supplied private houses, public fountains, and baths. As stated earlier, each destination should have received the same volume of water. But, Forbes calculates that in Rome, “up to 17% of the total water supply went to the baths” (Hodge, 1992). This is less than one-third of the water, so the majority of Rome’s water supply went to the public baths or private estates. In some Many factors contributed to the amount of water a citizen received. A citizen living in the highly populated capitol city of Rome would probably get less water than a citizen living in a smaller town. The buildings were higher in densely populated cities. The water could not reach these high rise buildings since there was no force pushing the water up. Residents in these buildings had to carry water from nearby public fountains. On the upside, residents in larger cities enjoyed waterworks such as the public baths. The public baths, like the Baths of Caracalla, were a place for relaxation and socialization.

2.3.3 Taps vs. Continuous Flow

An important aspect of Roman water distribution is the application of continuous flow. It was a way of life. A tap is a device that controls the flow of a liquid or gas from a pipe. There are many reasons why taps are used today: to avoid waste and cut down on consumption, to allow for repairs of pipes, and they allow rationing of water to places in need. The Ancient Romans did not find it necessary to use taps. In fact, there was only one design of tap found in the entire city and it was called the rotary plug.

2.4 Water Rules and Regulations

“…with such an array of indispensable structures carrying so many waters, compare if you will, the idle Pyramids or the useless, though famous works of the Greek” (Bruun, 1991). This quote is by none other than the very dedicated Sextus Julius Frontinus, Water Commissioner of Rome. Just like today’s cities, Ancient Rome had to issue rules and regulations for water distribution. Such are found in Frontinus’ written personal account of the water system of Rome: De Aquaeductu Urbis Romae. Aqueducts prioritized serving the citizens of urban centers while rural residents relied on other sources for agricultural and domestic needs, like wells and cisterns. Cynthia Bannon, from Indiana University, investigates the property rights to manage local water supplies from a small public aqueduct in Venafro, Italy. Venafro’s officials managed the city’s aqueduct with similar tactics as Rome’s officials managed their aqueducts. There were three types of access to water from the Venafro aqueduct: inside the town there was public access to fountains, outside the town some landowners along the route of the aqueduct were able to redirect water to their villa, and inside the town some residents had private water delivery to their property. Executive officials of Venafro, the duoviri, had power over the private delivery inside the town. These powers included: dividing and allocating the water in order to sell it, establishing a fee for use, and making a contract controlling these allocations. In today’s urban cities, like Seattle, government officials have similar powers, as will be discussed later. Although the duoviri were “selling” the water, it was not the buyers to keep. The buyer was basically paying for the right to use the water for a certain period of time. Illegal taps by landowners along the aqueduct, aquarii, or water men, creating false accounts and selling water under the table when individual grants expire. In Rome, the same corruption was happening with its aqueducts and Frontinus reflected on “the old days when Roman administrators privileged the public good over private interests” (Bannon, 2014). Aqueducts did not serve every region in the Roman Empire. Aqueducts prioritized serving the citizens of urban centers while rural residents relied on other sources for agricultural and domestic needs, like wells and cisterns. Aqueducts ran through the countryside, but poorer villages in these areas were never allowed to use them. The water running through the aqueducts was solely for people living in cities. Of course, there were some branches off the aqueduct sometimes tapped illegally. These branches were for the rich people in the countryside, “For example we know of one, off the Aqua Marcia, at Tivoli; perhaps typically, it was to serve a rich man’s villa not a rural community” (Hodge, 2005). People in rural areas relied on cisterns and wells, but it turns out that’s all they really needed. We will see that in populated cities, like Seattle, water costs more for residents that live outside of the city.

2.5 Rome’s Weakness

Aqueducts were some of the Roman Empire’s greatest achievements, but they also played a part in its downfall. As the Roman Empire began to crumple due to multiple reasons, Rome’s population dwindled and the water system was cut back. When the Barbarians invaded Rome, they first destroyed the aqueducts. It was a simple, yet very effective war tactic. It weakened an already distressed city and it forced the remaining citizens of Rome to drink very polluted water from the Tiber River. A nation is only as strong as its citizens. The citizens were drinking extremely poor quality water, so of course their health began to decline. As Ancient Rome’s water infrastructure deteriorated, the Roman Empire would soon follow. Later on, in the Great Man Made River section we will see that even today a country’s greatest strength can also be its greatest weakness.

3. Water and Urban Development in Seattle

3.1 History of Seattle Water System

Similar to Ancient Rome, Seattle experienced a city-wide fire and a population explosion that propelled the construction of a larger, more reliable municipal water system. The Great Fire of 1889 was a turning point for Seattle’s water supply. At the time of the fire, Seattle’s only source of water was the privately-owned Spring Hill Water Company and hydrants were only located on every other street. There wasn’t enough water to fight the fire. It was then that citizens voted to fund the creation of a city-owned water system. They purchased the upper Cedar River Watershed and began construction of a gravity-powered water system. Fifty years later, Seattle experienced a population explosion that jumpstarted the expansion of Seattle’s water system. In 1954, Roy Morse, the superintendent of Seattle’s water, wrote the Survey of Future Betterments to Seattle Water Department. It thoroughly outlines future plans for Seattle’s water system in order for it to sustain a growing population. An excerpt from this journal reads, “Metropolitan Seattle is growing rapidly. This growth continually reemphasizes the significance of enlarging the City’s water supply in time to meet demand” (Morse, 1954). This report outlines the predicted population growths and the increasing demands for water in Seattle. Figure 9 is Morse’s Population Forecast Chart from August, 1954. It is also important that the water supply capacity is kept ahead of water demand. Morse includes a chart (Figure 10) for supply and demand over an 80 year period. In depth, Morse analyzes future circumstances that would affect future water demands. For example, he takes into account that natural gas will be delivered to the Seattle Puget Sound region, thus increasing industrialization and subsequently increasing the demand for water. He expected that Seattle’s water demand would increase at a rate similar to other large U.S. cities, like Los Angeles or Philadelphia. Did Frontinus, Rome’s water commissioner, plan this far ahead?

Figure 9: Expected Population Growth in 1954 (Photo by Roy Morse).
Figure 10: Expected Supply and Demand for Water in 1954 (Photo by Roy Morse).

Morse also explains the expansion plans for Seattle’s Water System, such as building three more pipelines from the Tolt River Supply, “It is plainly evident that the Tolt River Supply and the Cedar River Supply from entirely different sources will provide a measure of reliability to the Seattle water system that it can never enjoy with only one source of water” (Morse, 1954). He also includes financial charts with estimated costs for these future expansions as shown in Figure 11. Although these expansions will cost the city a lot of money, they will also bring in revenue. Morse outlines the estimated revenues, expenses, and profits that these expansions could bring in Figure 12.

Figure 11: Estimated Timetable and Costs of Future Betterments (Photo by Roy Morse).
Figure 12: Estimated Revenues, Expenses, and Profits of Future Betterments (Photo by Roy Morse).

3.2 Urban Distribution

Seattle gets its water from two main watersheds, Cedar River and Tolt Reservoir. A watershed is an area of land that forms the drainage system for a stream or river and in this case provides habitat for salmon and important ecosystems. Melted snow and rainwater flow downhill and collect at the watershed. The land acts as a first step in cleaning the water. Water is drawn from a pump station that is 400 feet offshore and 50 feet deep to ensure the best water quality before treatment. Then, the water is treated at either the Tolt Reservoir or Lake Youngs treatment facilities. The treatment facility uses chlorine, ultra-violet light, and ozone to further clean it. Since the water comes from a very pure source, the treatment plants do much less treatment than most facilities (, 2017). The Seattle water system consists of 1,800 miles of pipes, 20,000 valves, and 188,000 water meters. After the water is treated, it travels through transmission mains that are 8 feet in diameter and run 20 miles to Seattle. Then, the water enters smaller connecting pipelines to be stored in tanks and pumping stations. Similar to aqueducts, gravity supplies a lot of the power for pumping water to Seattle since the water is captured at higher elevations than the city. Pumping stations are still needed to pump water over hilltops and throughout the city. Seattle’s watersheds supply 1.4 million people in the greater Seattle area. 70% of Seattle’s drinking water comes from the Cedar River Watershed. The city owns around 91,000 acres of land around this watershed and it’s the reason why the water is so clean. By owning this land, the city protects its water source. Just like ancient Rome, rapid population growth sparked Seattle’s action towards a municipal water system. Citizens voted to build the system in 1889 and it was up and running 12 years later. In its early years, the water system brought in 68.5 million gallons per day. Today, it delivers twice that amount. Which is surprising because Seattle’s population grew from 237,000 in 1910 to 1.4 million in 2017. Water consumption from these two watersheds averages 124 million gallons per day. This equates to around 90 gallons a day for one person. Figure 13 is a map from December 1997 of Seattle’s water system, including the distribution mainlines, supply mainlines, reservoirs, and tanks.

Figure 13: Seattle’s Water Supply (Photo by City of Seattle).

Today, it would be very difficult to provide everyone with free water because the entire water infrastructure must be constantly monitored, “It is monitored 24 hours a day, seven days a week, by people responding to breaks, power outages, pumping station issues and coordinating with street and electricity construction project” (, 2017). There are 658 employees that work on the water system and obviously they have to be paid. If a Roman aqueduct needed maintenance, Romans would make a slave fix it and it would not cost the government a dime. Today, it costs a lot more to keep a water system up and running. Another reason the government cannot provide everyone with free water is because the sanitation treatment of water is very expensive. Ancient Romans understood the importance of water quality, but they could only considered factors such as taste, temperature, smell, and appearance. They used the “good” water from springs to supply its city with drinking water instead of the lake or river water. Romans implemented inexpensive and sustainable sanitation methods, such as settling tanks. Some of these techniques could greatly benefit today’s developing countries that lack basic water technologies. Roman techniques did not require a power source, were built using local materials, and were usually low maintenance. They did not add chlorine or ozone to their water. Today, there is a lot of legislation regarding water regulations. The United States Environmental Protection Agency (EPA) enforces federal clean water and safe drinking water laws. It sets high standards for drinking water quality under the Safe Drinking Water Act (SDWA) by setting regulations for more than 90 contaminants. The process of making water safe is expensive. There is so much work that is required to make water safe and the people doing this work have to be paid. The problem is not distribution of water itself, rather it is the cost of distributing it.

3.3. Water Rules and Regulations

The city of Seattle provides an online version of the current municipal codesand it is available to the public. This handbook extensively covers a multitude of topics like fees for installing new connections to the main water line, the city’s right to shut off water at any given time, and penalties for unlawfully wasting water. There are codes found in this handbook that are similar to Frontinus’ insights on water administration. For example, code 21.04.020 reads, “Any person desiring to have premises connected with the water supply system of the City shall present at the office of the Seattle Public Utilities a copy of a building permit or a regular certified copy from the Director of the Seattle Department of Construction and Inspections” (, 2017). Although this code was not always followed in Ancient Rome, Frontinus made it clear that “all private connections to Rome’s aqueduct network had to be sanctioned by imperial permission” (Springer, 2012). Figure 14 is a chart of Seattle’s residential water rates as of January 1, 2017. Residents living outside the city of Seattle pay a little more than those living inside the city. Every year the residential water rates increase. This can be explained by the water system revenue requirement. Paul Hanna from Seattle Public Utilities explains, “In any given year, these rates and fees must be sufficient to pay the total costs of the water system and meet adopted financial targets” (Hanna, 2017 Water Rate Study). He also says that in 2015 there were no rate increases in 2015 because of the combination of an “improving economic climate and decisions on operational and capital spending made by SPU management” (Hanna, 2017 Water Rate Study). In 2016, Seattle experienced a record-breaking amount of rainfall between October 2016 and April 2017. Surprisingly, Seattle has the nation’s highest water bills. As of 2015, the monthly water bill for a typical family of four is $171.48. In comparison, the same family of four only pays $41.63 in Fresno, California. In Seattle, water costs less than a penny per gallon.

Figure 14: Residential Drinking Water Rates in Seattle, effective 1/1/2017 (Photo by

4. Modern Aqueducts

Today, aqueducts are still built to supply growing urban areas with enough water for the population and agriculture. Although today’s aqueducts lack the magnificent arches, they have been improved dramatically since Ancient Rome. They stretch over far more area of land bring a lot more water to cities in need. Also, modern aqueducts are built underground (Figure 15). Throughout time, similar events have jump started the construction of aqueducts: population growth and natural disasters.

Figure 15: Distinguishing features of Ancient vs. Modern Aqueducts (Photo by Encyclopedia Britannica, Inc).

4.1 State Water Project: California

California is the highest populated state in the United States with slightly more than 39 million people. By 2050, the population is expected to hit 50 million people. It is also the state with the driest summers. How are Californians provided with enough water year-round? They rely on a 700-mile long aqueduct, the California State Water Project (SWP). 2,000 years later, largely populated cities still use systems of aqueducts for their water needs. For drought-ridden California, aqueducts have been proven a viable water distribution system. The SWP is quite easily the longest aqueduct in the world. It successfully carries 650 million gallons of water a day from the Sacramento-San Joaquin Delta to the San Joaquin Valley and Southern California. See Figure 16 for the complete aqueduct route.

Figure 16: Map showing major features of the California State Water Project (Photo by the CA Legislative Analyst Office).

The water’s journey begins up north at the Oroville Reservoir, the state’s largest reservoir that carries rain and melted snow from the Sierra Nevada Mountains. Figure 17 shows an aerial view of the Oroville Reservoir and Dam.

Figure 17: Oroville Reservoir and Dam (Photo by Chris Austin).

Then, it runs down the Feather River to the Sacramento River and into the Sacramento-San Joaquin Delta. Once it reaches the Delta, the Banks pumping facility pumps the water 250 feet uphill to the first stretch of the aqueduct. The flow rate at this facility is about 7,000 cubic feet per second, which is extremely fast. Amy Quinton puts this number into perspective, “A cubic foot is about the size of a basketball. So imagine seven thousand of them, every second”(Quinton). After the Banks pumping facility, the water still has 400 miles left to reach Southern California and has two major obstacles in its path: The Grapevine and the Tehachapi Mountains. The Grapevine, also known as Tejon Pass, is the major route to get from Central to Southern California. Instead of drilling through the mountain like the Romans, the modern day California Aqueduct actually goes over the mountain. At the base of the Grapevine, the Chrisman Pumping Plant (see Figure 18) pumps the water 520 feet over the mountain. This pump needs about 44,000 horsepower.

Figure 18: The first uphill battle at The Grapevine (Photo by Chris Austin).

20 miles later, the water reaches the Tehachapi Mountains. Here, the Edmonston Pumping Plant uses 14 pumps to lift 2 million gallons per minute 2,000 feet up and over the mountains (see Figure 19). By drilling up and over the mountain, the engineers of the California Aqueduct save a lot of resources. Each pump requires 80,000 horsepower. Together, the 14 pumps consume about 60 megawatts, “enough electricity for a small city”(Choyce). The pumps generate so much power that each motor is given a “soft start.” A soft start involves temporarily reducing the load and torque in the power generator and electric current surge of the motor. Also, the pumps are not started all at once. They are started one by one every 6 minutes. Figure 20 shows the top of the pumps. The Edmonston Plant accounts for almost half of the California Aqueduct’s power use so they actually have their own power generator nearby.

Figure 19: The second climb (Photo by Chris Austin).
Figure 20: Six of the 14 pumps that push water over the Tehachapi Pass (Photo by Chris Austin).

After the water overcomes the Tehachapi Mountains, it continues to flow without any major pumping all the way to the end destination, Los Angeles and San Diego. Once it reaches its destinations, the water Throughout the aqueducts path, it provides water to 29 urban and agricultural water suppliers in Northern California, the Bay Area, the San Joaquin Valley, the Central Coast, and Southern California. Of this supply, 70% goes to urban users and 30% goes to agricultural users. It provides about 25 million Californians with water and about 750,000 acres of irrigated farmland. Similar to Roman water supply, the SWP is not the only source of water for Californians, but it is the main supplier. As stated earlier, the SWP provides 650 million gallons of water a day throughout California. 70% of this water is delivered to 25 million urban users. This equates to 455 million gallons of water a day to 25 million Californians. If every Californian received the exact same amount from the SWP, each person would get 18.2 gallons a day per person. This is not very accurate, though, because some locations rely a lot more on the SWP for their daily needs than others. For example, locations in California that receive more rainfall can rely on local reservoirs. On the other hand, Southern California heavily relies on the SWP since rainfall in this location is so sparse. Revisiting the possibility of continuous flow, it would not be economically nor environmentally conscious to implement continuous flow in Southern California. Taps are necessary in this location since it is constantly experiencing water shortages. California, especially Southern California, stores a great percentage of its water in reservoirs, “Reservoirs act as the state’s buffer against climate variability, stockpiling water during the rainy season for use during the dry” (California Institute of Technology, 2017). Climate change was not a concern in the year 100 AD, or at least that we know of. Rome did not depend on reservoirs for backup water as much as Southern California does today. As temperatures continue to rise in 2017 and beyond, water shortages will increase and the possibility of continuous flow becomes nonexistent. Also, California is known for its agriculture and a large portion, about 40%, of its water supply is used for irrigation. Perhaps, if California cuts back on agriculture, then it could supply its residents with constantly flowing water. California will face many challenges in the future of its water supply. As California continues to face over-population, it is subject to water shortages. Will the California Aqueduct provide enough water in the future? With future uncertainties like climate change and natural disasters, especially impeding earthquakes, is California prepared? A major earthquake could be catastrophic for Southern California as it would cut off a major water supply (Daniels, 2017).

4.2 The Great Man Made River

Aqueducts are a functioning, economically viable solution for today’s water distribution problems. But, if a nation is in turmoil and impending collapse, its infrastructure will ultimately follow that path and fail. Libya is an example of this domestic turmoil and lack of leadership. Libya was inspired by Roman engineering techniques. Their modern engineering project proves that aqueduct viability is independent of the time period. They followed in Rome’s footsteps and created a system of aqueducts flowing from city to city, supplying its citizens with continuously flowing water. In the 1980’s, Libya began The Great Man Made River Project (GMR), a modern engineering feat that was inspired by ancient Roman water distribution. There are many factors contribute to the success of a water distribution system. Libya is also an example that war and turmoil in a country will lead to the ultimate failure of water systems. Libya is a dry, arid desert with 6.3 million people relying on desalination plants in Tripoli and a salty aquifer for their water. Libya’s ex-president Muammar Gaddafi and the Libyan government believed that the Great Man Made River, the world’s largest irrigation project, would be the solution to the country’s water problem. It would bring freshwater to its citizens and turn Libya into a self-sustaining country. The United States, along with other western countries, never took it seriously so it was never really mentioned in the media. In reality, it was an extraordinary hydrological engineering system that improved the lives of many Libyans. It was the largest network of underground water pipes and aqueducts in the world, “The 2,333-mile network of pipes ferry water from four major underground aquifers in southern Libya to the northern population centers” (Topol, 2010). Similarly, the Romans created the largest network for transporting water. Figures 21 and 22 are water mainlines of the GMR (2007) and the Aqua Claudia (52 AD).

Figure 21: Soon-to-be underground portion of the GMR (Photo by Amusing Planet).
Figure 22: Underground portion of the Aqua Claudia (Photo by Kiley Rempp).

The GMR brought water from aquifers deep in the Sahara to the coast of Libya for domestic use, agriculture, and industry. There were 5 projected phases of construction (See Figure 23). Phase 1 was the largest phase and constructed 1,000 km of pipeline from As-Safir and Tazerbo to Benghazi and Sirte.

Figure 23: Simplified map of the GMR 5 phase project (Photo by Amusing Planet).

Phase 2 involved pumping water from the western aquifers to the Tripoli and Jeffara Plain. Phase 3 expanded on the phase 1 pipelines, providing eight new pumping stations, as well as supplied another 138,000 cubic meters of water a day to Tobruk and the coast. The last two phases were intended to extend pipeline form the Ajdabiya reservoir to Tobruk and connect the eastern and western systems into a single network in Sirte. The GMR had a daily capacity of 3.68 million cubic meters a day (972,153,153 gallons a day).

Figure 24: The arrival of water at the Gharyan Station in 2007 (Photo by Middle East Eye).

Adam Kuwairi recalls the profound impact the GMR had on him and his family, “The water changed lives. For the first time in our history, there was water in the tap for washing, shaving and showering. The quality of life is better now, and it’s impacting on the whole country” (Human rights investigation, 2011). Some, mainly Gaddafi, have called the GMR “the eighth wonder of the world.”

Figure 25: Construction of The Great Man Made River (Photo by Jaap Berk).

4.2.1 The GMR and Roman Aqueducts

There are important similarities between the 21st century Great Man Made River and ancient Roman aqueducts. Figure 23 and 26 compare the routes of Rome’s 11 aqueducts and the GMR pipelines. First, they were both supplied by underground water sources. Secondly, they were both extremely expensive endeavors. Overall, the GMR project cost about $25 billion. Similarly, the Romans spent a lot of money on public works and civil engineering projects. One famously extravagant structure is the Baths of Caracalla. A rough estimate for this project is $7 billion (DeLaine, 1997). A rough estimate for the cost of an aqueduct is “$US 1-10 billion” (DeLaine, 1997). Both projects were government funded projects that were in the same price range. Another similarity between the GMR and a Roman Aqueduct is the reason why the two nations built them. The Ancient Romans built aqueducts for many reasons, one being civic pride, “To possess an aqueduct was thus an outward mark of prestige and prosperity that none could mistake…to possess several marked a city as being indeed in the major league” (Hodge, 1992). Similarly, the GMR gave Libya something to be proud of. The GMR was so well recognized internationally that in 1999, UNESCO accepted Libya’s offer to fund the Great Man-Made River International Water Prize. It is “intended to reward the achievements of an individual, a group of individuals or a research institution having made fundamental and substantial contributions to the assessment, development, management and/or use of water resources in arid and semi-arid areas” (UNESCO, 2002).

Figure 26: Rome’s 11 Aqueducts (Photo by LA Times).

4.2.2 Libya’s Weakness

Libya was, and continues to be, a country in the midst of war and turmoil. So sadly, the GMR was destined to ultimately fail. Gaddalfi was a violent leader and threatened his own citizens so NATO, the North Atlantic Treaty Organization, believed it was necessary to take action. The GMR construction was interrupted in 2011 when NATO attacked one of the GMR’s pipe making facilities. This attack disrupted “70% of the population who depended on the piped supply for personal use and for irrigation” (Kaushik, 2015). NATO targeted critical water installations, which debilitated Libya’s water supply. Since this attack, “the country’s water infrastructure – and the suffering of its people – has only deteriorated further” (Ahmed, 2015). Tensions in Libya jeopardize the GMR’s future. The reliability of the GMR is also questionable. Unlike ancient aqueducts, the GMR is not powered solely by gravity. It uses electricity and this could be problematic in the future, “chronic power shortages in most areas of the country are seriously impeding the operation of water-pumping stations and wells” (Middle East Eye, 2016). UNICEF reports that power cuts and lack of fuel continue to risk the GMR’s future. Since there is constant turmoil in Libya, it’s difficult to find up-to-date information on the GMR.

Figure 25: Construction of The Great Man Made River (Photo by Jaap Berk).

The Great Man Made River was an engineering feat that was inspired by the Ancient Roman aqueducts. Even if it was just for a short period of time, the GMR brought life into Libya and changed the lives of its citizens. A sign posted along the GMR demonstrates its impact, “From Here Flows The Artery of Life Great Man Made River.” This sign emanates pride and strength, similar to the Roman aqueducts. As stated earlier, “Both the GMR and Roman aqueducts left important legacies, “Roman engineering accomplishments generated much wealth and prosperity, improving the daily lives of Romans” (Labate, 2016).

5. Conclusion

The Romans’ expertise in all civil engineering fields contributed to the success of the Roman Empire. They built efficient road systems, lasting bridges, and beautiful temples and buildings. But, it was truly their water systems that distinguished them as an advanced, dominant civilization. It was their water system that gave them the greatest advantage. Water infrastructure has the power to turn growing cities into strong civilizations. Ancient Rome is the perfect example of an ideal water distributor. They were able to organize a centralized water network that efficiently delivered water as well as washed it away. Modern aqueducts can carry a greater volume of water to farther places. Although they are much more advanced and impressive, they lack Roman ideals. Although it is unrealistic to supply the entire world population with free water, developed countries have the technology to distribute water to everyone. The issue is the cost to accomplish this. The Romans believed life’s most basic necessity well worth the cost, “Water isn’t optional. Water is necessary for our very existence, for our continued economic development, and for the health of the web of life that supports us” (Fleming, 2017). Ancient Rome embodied this idea. They knew providing citizens with clean drinking water led to a strong, healthy population. The Romans were innovators, incredible engineers, and impressive builders who embraced challenges. Combining today’s advanced technology and Roman ideals, global water distribution is possible.

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