People who knew about the New Orleans levee system feared the thought of a major hurricane making landfall near the city. They only hoped that time was on the Crescent City’s side.
Lt. Gen. Carl A. Strock of the U.S. Army Corps of Engineers said in a press conference, in which Construction Equipment Guide as well as other major media participated, that they thought the probability of New Orleans being hit by a Category 4 or 5 storm was one occurrence in every 300 years.
But hurricane activity had been increasing over the past several years, and beginning in 1997 and as recent as May 2005, published articles began warning of potential disaster if such a major storm were to hit New Orleans.
Time was up, though, and Hurricane Katrina, a Category 4 storm, made landfall Aug. 29 to the east of New Orleans, devastating America’s Gulf Coast and the city.
Red Flags Waving
In a May 2005 story from American Prospect Online, titled “Thinking Big About Hurricanes: What Would Happen If a Category 5 Hurricane Were to Hit New Orleans?” Chris Mooney, the story’s author, wrote: “In the event of a slow-moving Category 4 or Category 5 hurricane, with winds up to or exceeding 155 miles per hour, [the storm] could generate a 20-foot surge that would easily overwhelm the levees of New Orleans, which only protect against a hybrid Category 2 or Category 3 storm, with winds of up to 110 miles per hour and a storm surge of up to 12 feet. Soon the geographical bowl of the Crescent City would fill up with the waters of the lake [Pontchartrain], leaving those unable to evacuate with little option but to cluster on rooftops…”
“A direct hit,” the article continued, “from a powerful hurricane on New Orleans could furnish perhaps the largest natural catastrophe ever experienced on U.S. soil … it is only a matter of time before the ’big one’ hits. But long-term trends cut against the safety of New Orleans. Levees are subsiding, coastal wetlands are continually disappearing, and sea levels are rising.”
In anticipation of “the big one,” the article said that the “U.S. Army Corps of Engineers had ideas to bolster New Orleans’ defenses to withstand a Category 5 hurricane, saying that these included armoring the I-10 twin span, near the mouth of Lake Pontchartrain, with a miles-long bulwark rising out of the water. If tall and long enough, the sea wall dubbed ’Operation Block,’ would knock down any storm surge rising out of the Gulf of Mexico before it hit the lake – in short, stopping a hurricane with concrete.”
How The Levee System Failed
Katrina lashed New Orleans with winds of up to 145 miles per hour and a storm surge of 20 feet, ultimately causing a 200-ft. breech in the 17th Street Canal. There also were breaches to the London Avenue Canal and to the Industrial Canal in St. Bernard Parish. The Industrial Canal breach stretched up to 400 feet long. The end result of these breaches caused flooding that resulted in as much as 80 percent of New Orleans being submerged.
But officials noted during the Sept. 2 press conference that the 17th Street levee wall was “in excellent condition prior to the storm. The walls were designed at the same level of protection as the lakefront. The 17th Street Canal was constructed using an I-wall design.
“You go with a the T-wall when you need a much higher wall than an I-wall support. You go with an I-wall when you can’t squeeze a levee in. I this particular case, the area around the canal is extremely densely populated and there wasn’t any room to put a levee in,” said Al Naomi, a senior project manager of the U.S. Army Corps of Engineers.
These designs, explained Donald Vashon, chief of the engineering division of the U.S. Army Corps of Engineers in Washington, D.C., are based on a National Weather Service Standard Storm model. “The Corps also built in safety factors, freeboard zones and performed modeling for normal loading conditions. These walls were not designed with over-topping in mind.”
According to Loy Hamilton, a Memphis, TN-based civil engineer of the U.S. Army Corps of Engineers, water at the 17th Street levee “over-topped the floodwall, scoured behind the wall and caused it to collapse.”
Scouring, he explained, occurs when water washes a hole through the loose clay material that forms the levee. Once the clay material had become soaked, continued water pressure makes the loose material soak up water like a sponge. This created a 4- to 5-foot-deep hole, which, in turn, caused the water to rush out and flood, taking down a concrete retaining wall with it, Hamilton said.
But could anything have been done before Katrina made landfall to prevent any of the breaches?
Naomi said a plan was in place in the event of a storm, but “We have over 350 miles of levee built to certain standards. There’s not much you can do in a matter of 24 to 48 hours that’s going to make that situation any better.”
Walter Baumy, chief engineer for the Corps’ New Orleans District, added “We had no idea it would be this serious of an event because the storm wasn’t that strong the week before.”
However, Corps officials were preparing to respond no matter what happened and local levee agencies were “suring their systems wherever they thought they had weaknesses. So, there was an awful lot of activity prior to the storm happening.”
Repairing the Levees
By Sept. 10, all breaches were completely filled with sandbags.
In total, there were four critical breaches in New Orleans’ levee system: one at the 17th Street Canal; one at the Industrial Canal; and two (one minor and one major) at the London Avenue Canal.
Hamilton said the first attempts to plug the 17th Street Canal levees called for using hundreds of 20,000-lb. sandbags filled with sand and gravel. These bags were not filled to capacity, however, due to lifting constraints of Texas Army National Guard Chinook and Blackhawk helicopters. Initially, hundreds of 3,000 lbs were dropped into place. (Later, for all breaches, and average of 600 7,000-lb. sandbags were used.)
He said that when the water recedes and the area has dried, this levee will be re-compacted. Then it will be rebuilt to grade and section and a 200-foot stretch of concrete retaining wall that fell over after the storm will be replaced.
The 17th Street Canal breach was closed by nightfall on Sept. 5. Later that week, crews began stabilizing the repairs in case of another storm or a rise in the lake level.
Baumy added that sheet piling also was being driven at the mouth of the canal at 17th Street near Lake Pontchartrain to stop the water from flowing.
Because the London Avenue Canal proved most challenging to access due to Katrina flooding, Baumy said that not only had a variety of materials been used to plug these breaches, but “volunteers, contractors and state agencies banded together to get those materials to the London Canal. We’re adapting the engineering to [the materials] we can find.”
Crews also needed to adapt how they accessed the site.
“We even had contractors go down river to get to the affected sites,” Baumy said.
Non-stop convoys of 20-ton trucks delivered sand, gravel and large rock to build an access road to reach the larger of the two breaches (at press time, the Corps was still constructing an access road to the other breach.)
At press time, Army Corps crews were mobilizing equipment to install sheet piling to close off the canal at London Avenue.
The last of the critical breaches, at the Industrial Canal, was closed off on Sept. 10.
Drying Out
In other areas of the levee system, some levees were intentionally breached to allow water to flow out so that gravity could be used to drain the excess water. After this, pumps were used.
Baumy said the Corps has also been working closely with the New Orleans Sewage and Water Board to dig out the pump stations and get all the pumps going again.
As of Sept. 12, Corps officials said pumps were working at 25 to 35 percent of their total capacity. Many pumps were either still submerged or were still in the process of being dried out. In some instances, temporary, portable pumps were brought in to help the unwatering process. In other cases, generators had to be brought in to run pumps.
Corps officials noted that the city of New Orleans is compartmentalized with some areas of the city protected, while other areas were under water. The city has 15 sub-basins, all of which were not flooded. All, however, have their own levees, pumping systems and protection.
On Sept. 10, an average of 26 pumps were operating, pumping 9,125 cubic feet per second and 39 portable pumps were operating, pumping 723 cubic feet per second. In total, the Corps reported that water was being drained at the rate of at least one foot per day.
Initially, Baumy said it would take from 24 to 80 days to rid New Orleans of excess water. At press time, the Corps believed the entire city could be drained by Oct. 8.
Three Centuries of Levees in New Orleans
New Orleans has been in imminent danger of flooding for the past 300 years.
In 1728, the French passed the first levee law in what is now Louisiana, requiring all land owners to build a levee on their property, according to Craig Colten, professor of geography of Louisiana State University (LSU) in Baton Rouge, LA, and author of “An Unnatural Metropolis: Wresting New Orleans from Nature,” (LSU Press, 2005).
Colten said that in 1728, the average levee in New Orleans was four feet high and they extended a few miles along the City of New Orleans.
The French and Spanish used this law through 1803, which put the responsibility for building the levees on the property owners, he noted.
When Louisiana became a U.S. Territory in 1803, Colten said, landowners remained responsible.
In 1812, Louisiana became a state, he continued. When Louisiana’s statehood was approved, a series of three levee districts were created for the entire state – and the districts then became responsible for building and maintaining the levees.
In 1849, Colten said, the federal government gave Louisiana thousands of acres of swamp land that included the Atchafalya Basin and the area around Lake Pontchartrain. The federal government allowed the state to sell this land, but the proceeds from the sales had to be used to build levees.
“Levees built through the 1849 Swamp Land Act were inconsistent in size and height, resulting in frequent flooding along the Mississippi River,” Colten said.
“During the Civil War, the levees fell into a state of disrepair due to neglect,” he continued.
In 1879, Louisiana and Mississippi convinced the federal government to take responsibility for building and maintaining the levees. The end result was the creation of the Mississippi River Commission (MRC). The MRC oversaw the levees along the Mississippi River. The MRC also standardized heights for the levees, which, for New Orleans, was 18 to 19 feet.
“By 1927,” Colten added, “the MRC claimed the levees could withstand any flood. Then, in 1927, there was a great flood that devastated the levee system. At that time, a hole was blown in the system just below New Orleans to save the city. In 1928, through the U.S. Army Corps of Engineers, the federal government embarked on a non-stop improvement program for the entire levee system.”
The U.S. Army Corps of Engineers began flood control activities as a separate business area in 1928, added Bob Anderson, a public affairs officer of the U.S. Army Corps of Engineers in Memphis, TN.
The levees surrounding New Orleans, he said, are part of 8,500 miles of levees built or controlled by the U.S. Army Corps of Engineers. “Its levees, reservoirs and other flood protection projects have prevented $801 billion (adjusted for inflation through 2003) in flood damages. Flood control expenditures during the same period were $125.73 billion (again, adjusted for inflation), resulting in the projects preventing $6.37 in damage for each dollar expended,” he said.
Protecting the Crescent City
New Orleans lies between the Mississippi River and Lake Pontchartrain, with much of the land surface as much as 10 feet below sea level (and the level of the river and the lake). Its location is precarious with the constant threat of hurricane, yet, the city’s commercial and cultural importance make its protection a national priority.
In an effort to make the city more secure, Anderson pointed out that the U.S. Army Corps of Engineers has been involved in adapting the Mississippi valley to human requirements since 1804 and has been carrying out the Mississippi River Tributaries Flood Control Project since 1928. Primary features of the program included levees, floodwalls, flood gates, pumping stations, reservoirs on tributaries to hold back peak flows, control structures and floodways to relieve the pressure of excess river flows and channel improvements such as revetments, dikes and dredging to increase channel capacity and move floodwaters faster.
Anderson explained that “within New Orleans, the main features of flood protection are a string of levees, 13 feet to 17 feet high, built by the U.S. Army Corps of Engineers and maintained by the city along both banks of the Mississippi River and along the shore of Lake Pontchartrain. These levees have the effect of making New Orleans into a large bowl from which water is pumped. The New Orleans are part of a line of levees stretching from Cairo, IL, to Venice, LA.
“Construction of levees along Lake Pontchartrain in St. Charles, Jefferson, Orleans, St. Bernard and St. Tammany parishes began in 1967, and, as of Sept. 30, 2003, was 90 percent complete. The Lake Pontchartrain project also includes barrier complexes at the lake’s three main entrances from the sea. The cost of this project through Sept. 30, 2003, was $602 million, which included $157 million contributed by local sponsors.
“The Southeast Louisiana Urban Drainage Project, meanwhile, provides eight pumping stations, more than 30 drainage canals and underground drainage lines in Jefferson, Orleans and St. Tammany parishes. The cost of this project, from 1996 through Sept. 30, 2003, was $484 million, including $103 million in local funding.
“South of New Orleans,” Anderson continued, “levees protect the heavily developed areas of the Mississippi River to Venice, LA, at a cost of $179 million from 1996 through Sept. 30, 2004, including $26 million in local funds.
“The Corps’ work also includes the West Bank of the Mississippi River in Jefferson, Orleans and Plaquemines parishes with 57 miles of floodwalls and a discharge channel. Work on this project began in 1991 and was 36 percent complete at a cost of $75 million through Sept. 30, 2004, including $11 million in non-federal funding.”
According to Anderson, “two major flood outlets located north of New Orleans had been designed to allow up to half of the flood flows of the Mississippi to bypass New Orleans on the way to the Gulf of Mexico. The Bonnet Carre Spillway, completed in 1936 and located on the east bank of the Mississippi approximately 33 miles north of the New Orleans district, can pass 250,000 cu. ft. of water per second from the river into the Monganza Floodway. On the west bank of the Mississippi approximately 50 miles north of Baton Rouge, the spillway can pass 600,000 cubic feet per second into the Atchafalya and then to the Gulf of Mexico.
Who’s to Blame?
Not long after New Orleans was flooded, plenty of blame began being tossed about. President Bush, Senate Majority Leader Bill Frist, R- TN, as well as other members of Congress have already called for an investigation. Meanwhile, the dominant charge so far has been that there was a lack of funding by Congress to upgrade the levee system to withstand a Category 5 hurricane.
Some published reports claim money targeted for levee upgrades was moved to homeland security and to finance the war in Iraq. According to these reports, a Feb. 16, 2004, article in the New Orleans CityBusiness said that early in 2004, as the cost of the war in Iraq soared, President Bush proposed spending less than 20 percent of what the Corps of Engineers said was needed for Lake Pontchartrain.
Money for other work was allegedly repeatedly requested, with outcries that while the levee system, which is inspected annually by the U.S. Army Corps of Engineers, Louisiana’s parishes and independent inspectors, was in great shape, but that the levees were sinking. Stretches of levee in Metarie had sunk four feet, which required emergency funding.
Furthermore, with the 2004 hurricane season having been one of the worst in decades, the federal government in the spring of 2005 reportedly reduced hurricane and flood-control funding for New Orleans steeply. In one instance, money for the Southeast Louisiana Project (SELA) was reduced from $36.5 to $10.4 million, funding considered far below the amount needed to start the project. It was hoped that funds would be restored in fiscal 2006.
Meanwhile, other published reports claim President Bush proposed $10.4 billion for fiscal 2005 for Southeast Louisiana’s chief hurricane protection project — a sixth of what was actually needed. And, at the time, it was also thought that a four-to-five year study was needed to access what would be needed to upgrade the levee and flood control system in New Orleans to withstand a Category 4 or Category 5 hurricane.
Baumy, however, emphasized that $2.5 billion in levee projects that were under way by seven contractors at the time Katrina ravaged New Orleans “did not lead to the flooding.”
Strock added that the levees that had breached “were at full project design,” and that “the level of flooding that occurred would still have occurred.”
What Can Be Done?
According to Strock, “more than $300 million has been invested since 2002 to protect New Orleans from floods.” But with all of these projects and all of the money spent on them, questions remain about how to prevent this catastrophe from happening again.
Although at the moment many are blaming a general lack of funding to upgrade the 350 miles of levees in 15 segments in New Orleans, a $10 million to $12 million appropriation was approved by Congress so that a feasibility study to upgrade the levees to withstand a Category 5 hurricane could begin in 2006.
Corps officials estimate the study will take five to six years to complete at which point funding would be needed to implement the study’s recommendations. Then it would take several years until the recommendations became completed projects.
Much needs to be assessed in the aftermath of Hurricane Katrina. This continues to be done on a daily basis as rescue, repair and pumping continues.
As each day passes, one thing is clear, according to Bill Marcuson, president-elect-elect of the American Society of Civil Engineers and retired director emeritus of the Geotechnical Laboratory at the Waterways Experiment Station in Vicksburg, MS: “If the federal government doesn’t invest in the future, there is no future. That’s the point. That’s what happened in New Orleans.” CEG
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