Aqueducts—Great Engineering Feats!
By “Awake!” correspondent in Portugal
DO YOU have usable water at your disposal in the amount you desire? Many a housewife still uses her daily supply sparingly, since it must be drawn from nearby streams, springs or a distant well. Others, perhaps, never give the matter a second thought because modern advancement has made water so accessible. But it has not always been that way. Do you know how many city folks got their water centuries ago?
Aqueducts are the answer. Ancient aqueducts were usually long, narrow, completely closed-in tunnels that provided an aboveground channel for water to flow freely from a natural spring to a city. The flow of water was gravitational, the aqueduct having a gradual slant of one or two feet per mile. Where valleys existed, it was necessary to build a structure, in bridge-type form, that would carry the water on the same downhill slant. When the watercourse encountered hills or mountains, this required boring a hole right through the mountain.
Clearly, good engineering plans were necessary. The Bible relates that Hezekiah, king of Judah (745-716 B.C.E.), directed the building of an outstanding aqueduct cut through solid rock. He did this by using two teams of men working toward each other from opposite ends until they met in the middle. And this was no small tunnel, its average height being six feet and its length some 1,749 feet, or about a third of a mile!
Roman Aqueducts
The Romans later perfected the design of aqueducts and built scores of these in all parts of their vast empire. Long stretches of arches still stand as monuments to Rome’s engineering ability. Anyone who visits Europe can see them. One ancient aqueduct is at Pont du Gard, Nîmes, France. At Segovia, Spain, a magnificent 2,700-foot-long aqueduct built under Emperor Trajan (98-117 C.E.) is still in working order.
The amount of water transported by these aqueducts was tremendous. In 97 C.E. the nine aqueducts feeding Rome are said to have provided the city with a daily supply of some 38,000,000 U.S.A. gallons within its walls and another 20,000,000 gallons outside the walls! In those days water was a free gift to the community, no one having to pay for it. As for the building and maintenance expenses, these were generally paid from the spoils of war, the imperial treasury or by some wealthy benefactors. So it was that ancient Rome became famous for its public fountains, taps and baths.
Portugal’s Aqueducts
Some of Portugal’s many aqueducts were built by the Romans, such as those at Beja and Conimbriga. Most, however, have been constructed since the fifteenth century. A truly remarkable structure is the Vila do Conde aqueduct, which was built in 1350 C.E. and had a total of 999 elegantly designed arches. Another imposing sight is the Elvas aqueduct, consisting of no less than four tiers of arches spanning a deep ravine.
The city of Lisbon is gifted with the country’s most famous aqueduct, still operational, with tourists and local citizens alike appreciating the remarkable sight it affords. In 1731 C.E., a decree was issued by King D. João to build this aqueduct. It was really needed, for obtaining water at that time was indeed a daily challenge.
Imagine yourself in Lisbon some 250 years ago. Almost everyone is required to go to the central city tap to obtain a daily supply. Private consumers with their own wells are relatively few and highly privileged. So with two clay jugs in hand we walk to the city public water tap. What a large crowd is already gathered!
Although most people patiently wait their turn, some are rowdy and try to push and shove their way past others. Fights and brawls are almost a daily occurrence, and some people have been killed! Finally reaching the tap, we anxiously fill our jugs and quickly leave the crowd. Reflecting for a moment on the man in charge of the tap, we readily admit he has quite a job. Gladly we head home, thankful to have our daily supply—only eight quarts for all our needs!
No wonder work on the aqueduct was hailed as most welcome news to Lisboners. Building costs were met by applying a special tax on the purchase of such basic local items as salt, olive oil, wine, meat and straw. When finally completed some twenty years later, fresh water flowed to the city in quantity from the springs at Caneças, a distance of eleven miles.
The water is presently conveyed through hills by subterranean tunnels and across many ravines and valleys. The aqueduct system has been enlarged to bring water from thirty-six miles of tributaries, using a total of 127 arches in all. How majestic are the thirty-five high arches spanning the Alcântara valley in Lisbon, the largest central span being an arch 108 feet wide and 226 feet high, or equal in height to a twenty-two-story building! What a contrast today to see this old Lisbon aqueduct well lighted at night, stretching across the edge of the city, with modern highways passing under its arches. Appropriately, it is called the “Āguas Livres Aqueduct,” which means “Free Waters Aqueduct,” depicting the unobstructed flow of water to the citizenry.
Come with us to have a look inside this aqueduct. We are taken on top of the high arches covering the Alcântara valley and are surprised to learn that the aqueduct also served as a walkway for pedestrian traffic across the valley. Both sides of the water channel have a parapet wall protecting pedestrians from falling over the edge.
As yet we see no water, though, since the watercourse is completely covered. At regular intervals we observe small square towers on the aqueduct, each having a door that gives access to the water itself. Peeking inside one of these doors, we see the fresh water flowing down the channel—and how fast it flows! To our surprise we can enter the covered area and find ourselves actually inside the aqueduct.
Imagine, the tunnel is thirteen feet high! Parallel to the water a small walkway has been built. This is used by workmen for repairing any damages. A small notch in the wall contains a little clay mug, and we are offered a sample of this water. Oh, how refreshing and good it tastes! The flowing water is not too deep, only about seven inches, and the watercourse itself is no more than a yard wide. The aqueduct finally terminates in the heart of the city in a reservoir. Of course, this aqueduct is no longer Lisbon’s only source of water, since modern systems have long replaced gravitational methods.
Another indication of water distribution in bygone days is the many public water taps still functioning in Lisbon. As water supplies became more abundant and the population grew, many fine public taps were constructed. Interestingly, Lisbon city hall documents reveal much about the methods used to distribute water in the eighteenth century.
Each public water tap had a number of licensed men who would distribute drinkable water to householders by carrying an eight-gallon wooden barrel on their backs. Nondrinkable water was also sold on a house-to-house basis, but the water sellers attempting to sell such water as being drinkable were subject to heavy fines. Thus began the practice of paying for water delivered to one’s home. In Lisbon, even to this day some public wash tanks function where those not privileged to have running water in their home may go to care for the family laundry. Many also still use public baths.
Modern Aqueducts
In comparison with ancient aqueducts built mostly from masonry, wooden pipes or even bamboo material, modern aqueducts are colossal engineering undertakings, and may include canals, pipelines and tunnels. With urban growth and development producing sprawling cities having a population numbering into millions, man’s capacity to furnish an adequate water supply has been challenged. Outstanding accomplishments can be seen in the states of New York and California.
New York city produced the gigantic Catskill aqueduct to bring 500,000,000 gallons a day to that city. A commission was organized to guarantee the water supply of some fourteen cities in Southern California. The result was the notable Colorado River aqueduct, which brings water by pressure some 240 miles over several mountain ranges. This project involved the construction of three concrete dams, and five large pumping plants to lift water a total of 1,617 feet. Now a California State Water Project is being built that will dwarf any civil engineering job ever undertaken to transport water.
Without doubt, everyone appreciates that water is essential. Do you know, however, that there is more than one kind of “water”?
To a Samaritan woman who came to draw her daily water supply from a well, Jesus Christ said: “Everyone drinking from this water will get thirsty again. Whoever drinks from the water that I will give him will never get thirsty at all, but the water that I will give him will become in him a fountain of water bubbling up to impart everlasting life.”—John 4:13, 14.
This “water” is God’s provisions for gaining eternal life through Jesus Christ. Many have found such symbolic “water,” to their everlasting joy. We hope you too will have the curiosity to look for and to find this “water of life.”—Rev. 22:1.