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The Pumps Of New Orleans
Most of New Orleans is below sea level, and a good rainfall used to submerge it—until A. Baldwin Wood designed and installed a massive system of pumps to drain 20 million gallons a minute
Fall 1992 | Volume 8, Issue 2
It’s been raining all day. and New Orleans is sinking. Brown water is backing up the storm drains, filling the intersections, creeping toward people’s front steps. Children run home from school with their pants rolled up to their knees. Parts of Freret Street are underwater. Cleary Avenue is impassable. At the Camellia Grill on the corner of Carrollton and St. Charles, a regular complains to one of the cooks. “We never flooded this bad when I was young. It’s all the damn concrete: there’s no place for the water to go.”
A few dozen yards from the Camellia Grill are the huge earthen levees of Carrollton Bend. Behind them, unseen, the Mississippi is rising. The red-and-white gauge at Carrollton Station reads fourteen feet above sea level, but there’s no cause for alarm: in years past it has hit eighteen, even twenty. People have to look up at freighters passing by when the river is that high.
By New Orleans standards it turns out to be a very ordinary rain, only 3.5 inches. The drainage system catches up with the surplus water before nightfall. The city has seen much worse—the May 3, 1978. rain, for example, when 9.6 inches fell. That’s about 10 billion gallons of water, or about 40 million tons, over the area covered by the drainage system (after accounting for losses through retention). Draining New Orleans during a heavy rain is like draining a lake, because the city is ringed by levees, and most of it is several feet below sea level. When rain falls on New Orleans, it tends to stay there.
But New Orleans has one of the best drainage systems in the world. Seventeen hours after the first raindrops hit on that May 3, the city was dry again. Subterranean canals big enough to drive trucks through moved storm runoff to larger open canals, where massive twelve—and fourteen-foot screw pumps lifted it over the levees and sent it out to sea. The pumps were invented by a New Orleans native named Albert Baldwin Wood seventy-nine years ago, and each one can move nearly half a million gallons of water a minute. The city has scores of these pumps in operation. Taken together, the pumps of New Orleans could suck the Thames dry at London.
New Orleans was settled by the French in 1718 on high ground along the Mississippi River. The natural levees that made the site so promising were mountainous by Louisiana standards—twelve to fourteen feet above sea level—but the city soon spread out into less and less desirable areas. Life on the bayou was never very idyllic: floods turned the streets to quagmires, corpses floated in their graves, and mosquitoes, which bred in the pools of water that abounded throughout the area, were so thick that they would “fill every room in the house,” according to the architect Benjamin Latrobe in 1819. Visitors waded through a foot of water during one embarrassing Mardi Gras, and Tulane University once had to cancel classes because of high water in the lobby.
Mosquitoes carried yellow fever, and in 1878 an epidemic killed 4 percent of the population, raising the city’s accumulated death toll from the disease since its founding to 100,000 people. Cholera and typhoid fever were also quite common. Conditions were extremely unsanitary. There was no sewerage system until 1899, so residents dumped refuse directly into the river. To avoid drinking river water, people collected rainfall in cypress tanks. The tanks rotted and the water stagnated, breeding more mosquitoes. The city’s entire drainage system consisted of a few weed-choked canals and four steam-powered paddle wheels that vainly tried to lift the storm run-off over the levees and into the lake. “Mud, mud, mud,” Latrobe’s three-word description of the city in 1819, remained accurate throughout the nineteenth century.
Conditions didn’t improve until the creation of the Sewerage and Water Board in 1899. (Women did not have the franchise in Louisiana at that time, but all property owners were allowed to vote in municipal-bond referenda. Since three-quarters of the city’s property owners were women, their support for the bond issue that established the drainage and sewerage systems was crucial.) The board was classified by law as “unattached,” meaning that only a statewide vote of the people can change its mandate—an important advantage in a state with Louisiana’s colorful political traditions. The board was given complete executive power over the city’s flood control, and it made an excellent start by hiring a young engineer named A. Baldwin Wood.
If any man could claim to have saved New Orleans from Its geography, it was Wood. Born a year after the great epidemic of 1878, Wood was a direct descendant of Francisco de Bouligny, one of the great Creole patriarchs of the city. Wood graduated with honors from Tulane in 1899 and promptly got a job with the board as an assistant manager of drainage. He immediately set about improving the city’s drainage system. By the age of twenty-seven he had invented a six-foot centrifugal pump that was the largest of its kind in the world. He followed that with an ingenious flap-gate design that prevented water from backing up the pumps when they were not in use. Finally, in 1913 he presented the board with the design and rights to a twelve-foot screw pump that had the capacity to move more water than any pump in existence.
Initially the city council (whose approval was needed for large projects) wanted to turn down Wood’s plan. It had no confidence in the young engineer who, unpaid, had spent his evenings designing the novel pump. But eventually the council was prevailed upon, and a $159,000 contract was awarded to the Nordberg Manufacturing Company of Milwaukee for thirteen patented Wood screw pumps. By the end of 1915 the city had installed the first eleven and was on its way to constructing one of the largest pumping facilities in the world.
Wood’s design placed impellers at the summit of a pipe siphon that emerges from the concrete floor of the pump house. Priming is achieved by rotary vacuum pumps; the vacuum is broken simply by admitting air into the casing before stopping the pump. The casing is split horizontally to allow easy access to the pump’s interior. The pumps are self-oiling, the bearings do not come in contact with water or grit, and there are no valves or gates between the turbine and the in-take and discharge canals. The pumps generate very little vibration, so they do not require heavy foundations. On a later device, the Wood trash pump, the blades and pump casing are so rounded that nothing can get caught on them—stockings, rags, two-by-fours, whatever finds its way into a New Orleans sewer. In the old days engineers had to open the pumps and clean them out every eight hours of operation. A Wood trash pump has yet to be opened for cleaning.
As New Orleans became famous for its herculean drainage facilities, other cities and countries tried to lure Wood away with fatter paychecks. London offered him a full-time job, but he turned it down twice. Over the years he was retained as a consultant by private and public agencies in cities in the United States, Canada, and Europe. His one condition for outside work was that he not have to leave New Orleans. After thirty-two years with the water board, Wood’s salary was only $7,500.
Wood’s pumps saw service in China, Egypt, and India. His biggest international project was the Zuyder Zee in Holland, where a line of pumping stations stretched across inundated farmland from Amsterdam to Zwolle. Wood never set foot in Holland, but he did send blueprints to the Dutch engineers. When they were unable to follow the plans, he invited them to the United States, and he pointed out their mistake within five minutes. Years later his widow visited Holland and was received by Dutch officials at a pumping station turned out in plush red carpeting.
Wood’s other contributions to the city of New Orleans were numerous, if not as famous as his twelve—and fourteen-foot pumps. He invented one of the first automatic sewage-moving pumps in the country and a machine for testing hydraulic meters. He developed a money-saving technique for “half-soling” the undersides of worn sewer pipes. In all, Wood had thirtyeight patents, of which six or eight were “quite successful,” in his words.
Despite his accomplishments, Wood took care to stay well away from the public eye. He asked National Geographic not to use his name in an article on the New Orleans drainage system. He reportedly would buy two seats on a train so that no one would sit next to him. His life consisted of hard work for the water board and weekend sailing trips on his sloop Nydia , moored in Biloxi, Mississippi, by his beach house.
The Nydia was the joy of Wood’s existence. Once, moored peacefully in a hidden cove in Florida, Wood woke up to the sound of explosions. Geysers of water were shooting up all around him; he had stumbled into a bombing range. He quickly hoisted his sails and fled the area. Another time the boat was stolen by escaping convicts. After it was recovered, Wood built a lighthouse on his property, with its beam pointing at the boat. When a hurricane blew the lighthouse over, he rigged a pulley system and righted it himself.
Wood often told his friends that he hoped he would die on the Nydia , and coincidentally, on May 10, 1956, he got his wish while on an afternoon sail. A friend of his, Capt. Louis Gorenflo, later described to a reporter the fulfillment of Wood’s wish: “There was a spanking Southeaster and just after I had cleared the harbor I saw the Nydia . … As Mr. Wood sailed across my port bow, he gave me that customary wave. Moments later … I saw him move to a kneeling position, pause for a while with his chin resting on the tiller, then slump gradually to the deck.” Wood so treasured his boat that in his will he left money to install the Nydia in a small glass building on the Tulane campus.
Wood’s pumps go a long way toward keeping New Orleans dry, but they are inseparable from a levee system that encircles the city. The pumps get rid of rain that falls on the city; the levees keep the river’s waters out. Levees are huge earthen walls that confine a river to its channel and keep it off the settled floodplains on either side; the Mississippi has levees stretching all the way to Cairo, Illinois, where the Ohio joins it. Levees are helpful in controlling routine flooding, but during times of particularly heavy flow they can actually make matters worse. When a river can’t overflow onto its floodplains, it has no choice but to rise higher and move faster, endangering people downstream. That was never so clearly demonstrated as during the spring of 1927, when one of the greatest floods in United States history began making its way down the Mississippi.
Engineers knew it was going to be a bad one that year because the spring rises on the major tributaries—the Missouri, the Ohio, and the Arkansas —had all coincided. River gauges up and down the Mississippi Valley were setting records. On April 15 more than fourteen inches of rain fell on New Orleans, a deluge of almost biblical proportions. Three days later the river gauge in Cairo reached 56.2 feet, the highest reading ever. The levees were sure to break somewhere along the river, but the question was where. Disaster for one town meant lower water levels and less danger elsewhere. Armed guards patrolled the riverbanks to make sure that no one settled the question with a stick of dynamite. Finally, on April 21, crevasses (levee breaches) occurred at Mound Landing, Mississippi, and Pendleton, Arkansas. The next day the main levee failed in Greenville, Mississippi, and a wall of brown water twenty feet high swept through the fields.
Flooding continued for weeks throughout the Mississippi Valley. In the end several hundred people were killed, and almost 700,000 were left homeless. Damage was at least a billion dollars in today’s terms. “The Flood of ‘27 was of such devastation that it awakened the realization local agencies couldn’t handle it,” says Fred Chattery, chief engineer for the New Orleans branch of the U.S. Army Corps of Engineers, which runs the system of levees along the Mississippi. “It cried out for a total solution.”
The solution was the Flood Control Act, which Congress passed the following year. Up until then the belief had been that safety lay in building bigger and bigger earthworks to protect the settled floodplains of the river. That approach traded minor yearly flooding for rare, unpredictable disasters. When a main-line levee breaks, it unleashes a destructive force that a river could never achieve on its own. As Maj. Gen. Lytle Brown wrote at the time of the 1927 flood, “The cost of a levee increases more rapidly than the square of its height, and the destructiveness of the crevasse increases in like proportion.”
The flood-control plan included new levees and similar structures, with measures to make them more effective; cutoffs of several loops in the meandering river to shorten it by 150 miles, making drainage that much faster; and construction of the Bonnet Carré Spillway, which can drain 10 percent of the expected floodwaters away from New Orleans to Lake Pontchartrain. (The Bonnet Carré has since been supplemented upriver by the Morganza, West Atchafalaya, and Bohemia floodways, all of which route floodwaters past major population centers. In all, less than a third of the expected floodwaters now go past New Orleans down the original Mississippi River.)
Because engineers have been so successful in controlling the flow of the Mississippi, pumps are not needed to save the city from river-borne catastrophe. Rather, they are most valuable in the day-to-day task of draining what is in effect a huge catch-basin. Today there are twentyone pumping stations in New Orleans, with a combined pumping capacity of 47,000 cubic feet of water per second. Their combined force would propel a ten-foot column of water a mile and a half in the air. Storm run-off collects in canals under the city streets and is moved by a set of pumping stations to the edges of Lake Pontchartrain and Lake Borgne, to the north of the city. There a different set of pumping stations takes over and lifts the runoff over the twenty-five-foot levees. Both lakes are saltwater and eventually drain into the Gulf of Mexico. The Mississippi runs along the southern edge of the city, but it isn’t practical as a way of getting rid of storm run-off because its flood levels are much higher than those on the lakes.
Station 6 is the biggest pumping station in the city, and until recently it was the biggest in the world. It could fill the Superdome in two and a half hours. It pushes water north along the Métairie Relief Outfall Canal to Station 12, where it is lifted into the lake. Ordinarily Station 6 has a staff of four, but during emergencies up to thirty people may be swarming over the facility. The first-floor windows of the station are bricked in to keep out floodwaters. Inside, everything is big: control dials the size of wall clocks, machine bolts bigger than your fist. At full power the pumps sound like jet airplanes taking off.
From the outside the pumps are simply large metal drums with an axle running through the center. Water passes through metal screens and is pulled up huge intake pipes. Once the water enters the pump, it is screwed forward by the rotating turbine and released on the other side of the pump house. There it courses down cement spillways and continues down the canal toward the outfall stations. The pumps are driven by electric motors powered by a twenty-five-cycle AC system. They are virtually immortal. The original twelve-foot pumps were installed in 1915 and are essentially as good as new. The only time one has ever broken down was during the 1978 flood, when a car tire somehow got into the casing and snapped a blade. The water board has its own steam and gas turbines that generate up to 61,000 kilowatts for its pumping stations; another 18,000 kilowatts can also be converted from the local power company. In addition, some pumping stations have their own emergency generators above flood levels. They would slowly empty the city in the case of a complete inundation.
“To give you an idea of the amount of water moved by Wood’s screw pumps,” says Larry Bodet, a senior civil engineer at the water board, “understand that an average of fifty-eight inches of rain a year falls on the city of New Orleans. With a 35 percent retention rate that’s 8,418,358,475 cubic feet of water. Multiply that by seven and a half, and you get the number of gallons. Every drop of that must be lifted up over the levees and into the lake.”
The reason New Orleans has any flooding at all, he says, is that the city uses a “dry” drainage system. That means that there is nowhere for runoff to be stored temporarily until the pumps can get rid of it. A “wet” system—one with big canals or a swamp, for example—needs fewer pumps because city streets aren’t underwater and there is no urgency to drain the area. The cost of a pumping system that could get rid of water as fast as it fell—or poured through a levee breach —would be too high for New Orleans to afford. A catastrophic storm might cost $100 million in damage. It would be easier to absorb that cost every century or so than to improve a pumping and drainage system that is already worth $1.5 billion.
Down the hall from Bodet is Wesley Busby. Both men are thirty-year veterans of the water board. Busby has a photograph in his office (shown on page 42-43) of the inside of a fourteenfoot screw pump during construction. It looks big enough to gallop horses through four abreast. Secretaries are posed for the photograph inside the pump’s huge iron belly. One of them reaches down to hold the hand of a smiling A. Baldwin Wood.
“If we turned off all the pumps, this city would just go back to the swamps,” says Busby. “In the event the levees were topped during a hurricane, NOPSI [the city’s power company] would be out; even the water-board generators would be out. So we have two stations at flood elevations plus ten [feet] that would have to empty the city. Basically you’re looking at a saucer full of water.”
Fred Chattery has been with the Corps of Engineers since 1946. Photographs of levees and a map of the Mississippi Delta hang on his wall. The river itself, brown and swollen with spring rain, fills the view from his office window. The corps building sits directly on the levee at Carrollton Bend, and the official city flood gauge is visible down below in the muddy water (“our public relations gauge,” Chattery calls it). It has been raining hard since morning, and all over the city Wood’s screw pumps are going full bore.
“Floods are getting worse because the land is subsiding,” says Chattery. “That’s a characteristic of greater development. And there’s more storm run-off because it’s all concrete now. Those are areas where you could’ve hunted rabbits when I was a boy.”
What happened was that development upstream—in other words, development anywhere in the 41 percent of the contiguous United States that makes up the Mississippi River Basin—increased the flow of the river and reduced the amount of silt it carried. Silt builds wetlands, which absorb heavy river flow during times of flood. Today’s increased river flow deepens the channels, which then move water faster and consequently raise flood levels downstream. This process has been going on for the past hundred years.
“We have something called a project flood,” says Chattery. “It’s the largest hypothetical flood the system must be able to pass. That happens to be three million cubic feet per second at the latitude of Old River [the Louisiana-Mississippi line]. The flood of ‘27 was only 27 percent of that. The likelihood of a flood too big to handle is very remote. Besides, it wouldn’t invalidate the whole system; it would just cause some damage.”
The linchpin of the entire system—pumps, spillways, the works—is the levee. Most levees are made of earth and carefully calculated to withstand the force of the river. Engineers must take into account everything from the stability of different soil types to the centrifugal force of water at river bends to build a safe levee. Taken with the control structures upstream, the levee system around New Orleans could protect the city from virtually any river flood possible. The levees are also built to take a direct hit from a Category 3 hurricane, the other major natural disaster that the city might have to face. A Category 3 generates twelve-foot tides and 130-miles-perhour winds. In 1969 Hurricane Camille, with twenty-six-foot tides and 190-mph winds, missed New Orleans by sixty miles. It smacked Gulfport, Mississippi, instead, leaving bodies hanging from trees and floating in the gulf. Hundreds of people were killed, and 200,000 had to evacuate. If Camille had hit the more densely populated New Orleans area, the toll would have been much worse. At this point a Camille-type hurricane is about the only thing that could overwhelm New Orleans. Although the pumping system wouldn’t be able to save the city from flooding, it would speed drainage and help bring things back to normal. People would die, but the city would not.
A year before his death Wood was presented with a plaque commemorating his fifty-five years of service with the Sewerage and Water Board. Mayor deLesseps Morrison handed it to him, saying, “Mr. Wood, it’s practically impossible for the city of New Orleans to compensate you for what you’ve done.” Thanks to A. Baldwin Wood, New Orleans will always be able to re-emerge from the swamp that nature wants it to be.