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In the early 1900s a simple glass of water could quench your thirst—or kill you. The safe drinking water that much of the world takes for granted today did not exist, and deadly waterborne diseases such as cholera, typhoid fever, and dysentery were a constant threat. Thanks to the efforts of scientists and engineers committed to protecting the public health, tap water in most of the world is safe to drink and waterways are guarded against pollution.
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1900 |
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Sanitary and Ship Canal opens in Chicago
In Chicago the Main Channel of the Sanitary and Ship Canal opens, reversing the flow of the Chicago River. The 28-mile, 24-foot-deep, 160-foot-wide drainage canal, built between Chicago and the town of Lockport, Illinois, is designed to bring in water from Lake Michigan to dilute sewage dumped into the river from houses, farms, stockyards, and other industries. Directed by Rudolph Hering, chief engineer of the Commission on Drainage and Water Supply, the project is the largest municipal earth-moving project of the time.
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1913 |
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Los Angeles–Owens River Aqueduct
The Los Angeles–Owens River Aqueduct is completed, bringing water 238 miles from the Owens Valley of the Sierra Nevada Mountains into the Los Angeles basin. The project was proposed and designed by William Mulholland, an immigrant from Ireland who taught himself geology, hydraulics, and mathematics and worked his way up from a ditch tender on the Los Angeles River to become the superintendent of the Los Angeles Water Department. Mulholland devised a system to transport the water entirely by gravity flow and supervised 5,000 construction workers over 5 years to deliver the aqueduct within original time and cost estimates.
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1913 |
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Activated sludge process
In Birmingham, England, chemists experiment with the biosolids in sewage sludge by bubbling air through wastewater and then letting the mixture settle; once solids had settled out, the water was purified. Three years later, in 1916, this activated sludge process is put into operation in Worcester, England, and in 1923 construction begins on the world’s first large-scale activated sludge plant, at Jones Island, on the shore of Lake Michigan.
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1914 |
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Sewerage Practice, Volume I: Design of Sewers
Boston engineers Leonard Metcalf and Harrison P. Eddy publish American Sewerage Practice, Volume I: Design of Sewers, which declares that working for "the best interests of the public health" is the key professional obligation of sanitary engineers. The book becomes a standard reference in the field for decades.
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1915 |
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New Catskill Aqueduct is completed
In December the new Catskill Aqueduct is completed. The 92-mile-long aqueduct joins the Old Croton Aqueduct system and brings mountain water from west of the Hudson River to the water distribution system of Manhattan. Flowing at a speed of 4 feet per second, it delivers 500 million gallons of water daily.
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1919 |
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Formula for the chlorination of urban water
Civil engineer Abel Wolman and chemist Linn H. Enslow of the Maryland Department of Health in Baltimore develop a rigorous scientific formula for the chlorination of urban water supplies. (In 1908 Jersey City Water Works, New Jersey, became the first facility to chlorinate, using sodium hypochlorite, but there was uncertainty as to the amount of chlorine to add and no regulation of standards.) To determine the correct dose, Wolman and Enslow analyze the bacteria, acidity, and factors related to taste and purity. Wolman overcomes strong opposition to convince local governments that adding the correct amounts of otherwise poisonous chemicals to the water supply is beneficial—and crucial—to public health. By the 1930s chlorination and filtration of public water supplies eliminates waterborne diseases such as cholera, typhoid, hepatitis A, and dysentery. The formula is still used today by water treatment plants around the world.
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1930 |
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Hardy Cross method
Hardy Cross, civil and structural engineer and educator, develops a method for the analysis and design of water flow in simple pipe distribution systems, ensuring consistent water pressure. Cross employs the same principles for the water system problem that he devised for the "Hardy Cross method" of structural analysis, a technique that enables engineers—without benefit of computers—to make the thousands of mathematical calculations necessary to distribute loads and moments in building complex structures such as multi-bent highway bridges and multistory buildings.
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1935 |
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Hoover Dam
In September, President Franklin D. Roosevelt speaks at the dedication of Hoover Dam, which sits astride the Colorado River in Black Canyon, Nevada. Five years in construction, the dam ends destructive flooding in the lower canyon; provides water for irrigation and municipal water supplies for Nevada, Arizona, and California; and generates electricity for Las Vegas and most of Southern California.
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1937 |
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Delaware Aqueduct System
Construction begins on the 115-mile-long Delaware Aqueduct System. Water for the system is impounded in three upstate reservoir systems, including 19 reservoirs and three controlled lakes with a total storage capacity of approximately 580 billion gallons. The deep, gravityflow construction of the aqueduct allows water to flow from Rondout Reservoir in Sullivan County into New York City’s water system at Hillview Reservoir in Westchester County, supplying more than half the city’s water. Approximately 95 percent of the total water supply is delivered by gravity with about 5 percent pumped to maintain the desired pressure. As a result, operating costs are relatively insensitive to fluctuations in the cost of power.
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1938-1957 |
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Colorado–Big Thompson Project
The Colorado–Big Thompson Project (C-BT), the first trans-mountain diversion of water in Colorado, is undertaken during a period of drought and economic depression. The C-BT brings water through the 13-mile Alva B. Adams Tunnel, under the Continental Divide, from a series of reservoirs on the Western Slope of the Rocky Mountains to the East Slope, delivering 230,000 acre-feet of water annually to help irrigate more than 600,000 acres of farmland in northeastern Colorado and to provide municipal water supplies and generate electricity for Colorado’s Front Range.
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1951 |
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First hard rock tunnel-boring machine built
Mining engineer James S. Robbins builds the first hard rock tunnel-boring machine (TBM). Robbins discovers that if a sharp-edged metal wheel is pressed on a rock surface with the correct amount of pressure, the rock shatters. If the wheel, or an array of wheels, continually rolls around on the rock and the pressure is constant, the machine digs deeper with each turn. The engineering industry is at first reluctant to switch from the commonly used drill-and-blast method because Robbins’s machine has a $10 million price tag. Today, TBMs are used to excavate circular cross-section tunnels through a wide variety of geology, from soils to hard rock.
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1955 |
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Ductile cast-iron pipe becomes the industry standard
Ductile cast-iron pipe, developed in 1948, is used in water distribution systems. It becomes the industry standard for metal due to its superior strength, durability, and reliability over cast iron. The pipe is used to transport potable water, sewage, and fuel, and is also used in fire-fighting systems.
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1960s |
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Kuwait begins using seawater desalination technology
Kuwait is the first state in the Middle East to begin using seawater desalination technology, providing the dual benefits of fresh water and electric power. Kuwait produces fresh water from seawater with the technology known as multistage flash (MSF) evaporation. The MSF process begins with heating saltwater, which occurs as a byproduct of producing steam for generating electricity, and ends with condensing potable water. Between the heater and condenser stages are multiple evaporator-heat exchanger subunits, with heat supplied from the power plant external heat source. During repeated distillation cycles cold seawater is used as a heat sink in the condenser.
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1970s |
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Aswan High Dam
The Aswan High Dam construction is completed, about 5 kilometers upstream from the original Aswan Dam (1902). Known as Saad el Aali in Arabic, it impounds the waters of the Nile to form Lake Nasser, the world’s third-largest reservoir, with a capacity of 5.97 trillion cubic feet. The project requires the relocation of thousands of people and floods some of Egypt’s monuments and temples, which are later raised. But the new dam controls annual floods along the Nile, supplies water for municipalities and irrigation, and provides Egypt with more than 10 billion kilowatt-hours of electric power every year.
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1980s |
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Bardenpho process
James Barnard, a South African engineer, develops a wastewater treatment process that removes nitrates and phosphates from wastewater without the use of chemicals. Known as the Bardenpho process, it converts the nitrates in activated sludge into nitrogen gas, which is released into the air, removing a high percentage of suspended solids and organic material.
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1996 |
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UV Waterworks
Ashok Gadgil, a scientist at the Lawrence Berkeley National Laboratory in California, invents an effective and inexpensive device for purifying water. UV Waterworks, a portable, low-maintenance, energy-efficient water purifier, uses ultraviolet light to render viruses and bacteria harmless. Operating with hand-pumped or hand-poured water, a single unit can disinfect 4 gallons of water a minute, enough to provide safe drinking water for up to 1,500 people, at a cost of only one cent for every 60 gallons of water—making safe drinking water economically feasible for populations in poor and rural areas all over the world.
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