The Geography of New Orleans
Original Publication Date: September 2007
THE MISSISSIPPI RIVER
The city of New Orleans is located near the mouth of the Mississippi River [Figure 5]. Placing a city there was intentional but also problematic. The growth of trade and commerce necessitated a port at the mouth of this central artery of the North American continent. The site was also prone to dangers posed by proximity to entities likely to do damage to their environs. By using the narrow inset at Bayou St. John, the delta could be bypassed. This shortcut saved traders the problem of traveling 110 miles from the Gulf of Mexico [Figure 3b].
Placing a city at the mouth of a river is not inherently problematic but the Mississippi is an unusual river. Most deltas are embayed, i.e. the sea enters the river at the mouth and floods it, making it easy to form a city such as London on the Thames. But the delta of the Mississippi River is not embayed and protrudes out into the Gulf of Mexico [ma], making it difficult for ships heading to sea to use the port. The rapidly flowing river brings its own natural sediment and the earth’s crust literally sags beneath it. The mouth extended upstream gets higher with each new flood, but these floods may change the direction of a river over time, as has been the case with the Mississippi. The question became how to maintain the port location once New Orleans was located there.
Over the millennia, the Mississippi has changed course in both easterly and westerly directions, creating the six delta lobes that have formed the entire coastline of southern Louisiana [Figure 11]. These six ‘mouths’ of the Mississippi are all flanked by extreme lowlands, little more than mudflats. These river mouths are hard to find but there is no way to get water access to the Mississippi except through these mouths and no way for coastal ships to cross the river further upstream.
Another unusual aspect of the Mississippi is the land formation on its banks and beyond. Over the millennia, each time the river overflowed, it left deposits of silt, clay and other materials. The result was a natural levee that rose 10 to 15 feet high and stretched a mile or so beyond the riverbank. The original city of New Orleans was placed on this natural levee [Figure 3a]. There was a gradual decline away from the river. Again, unlike most land near rivers where the land rises away from the river, the banks of the Mississippi have remained nearly level. The materials that settled back from the river created a sludge-like swamp, difficult to inhabit. The high water table did find an outlet from the river to Lake Pontchartrain via Bayou St. John [Figure 3b], a crucial path during the early decades after the city’s founding.
Many of the problems that New Orleans faces are not local in nature but due to its placement at the outfall of the continent’s largest natural drainage system [Figure 5]. Problems as distant as the melting of snow in the Ohio River Valley lead to flooding in New Orleans. Other problems are man made. Until the 20th century, the river was used as a means of sewage and garbage removal, as residents sent their trash out to the Gulf of Mexico.
The location of New Orleans was essential as the gatekeeper of US economic interests and access for foreign trade. Until 1900, the terrain determined growth and habitation was largely restricted to the natural levee [map]. The result is a port city with a tropical climate located mostly below sea level. The land itself is not conducive to settlement. There is little solid foundation as bedrock is over 75 feet down. Where silt settles from river overflow, the land is arable but clay deposits, usually back from the riverbank, drains poorly and makes a bad foundation.
Drainage of this very damp soil is both a necessity and a big problem. Absent any real gradient, a gravity driven flow is impossible. Technology has provided some assistance, but heavy rains and frequent floods limit the amount that can be removed. The result is a high water table that left the city mired in a disease prone setting,
The topography has rendered the city completely dependent on structural means to provide transportation and control internal flooding. Many of the steps taken have resulted in other problems. Placing canals through wetlands to ease transportation has reduced the capacity of the marshes to counter storms surges, a natural means of flood prevention.
Trade is the very reason for the existence of New Orleans. The city’s fortunes ebb and flow with its ability to provide an arena for the exchange of commodities. And for the first half of the nineteenth century, no artery was more important to this endeavor in the growing United States than the Mississippi River. The advent of the steam boat enhanced the river’s importance although railroads soon took precedence only to be replaced in the twentieth century with cars and trucks. Shipping remained important and kept the city’s fortunes alive. However in the years following World War II, the shift to container shipping rendered New Orleans’ port facilities outmoded, leaving the city with expensive and unpalatable alternatives.
Within the city itself, the river provides transportation although streams flow away from the Mississippi. Intercoastal shipping, therefore, could not be taken through the river’s delta but required locks and a canal system which was not done until 1909. Throughout the 20th century, canals were used for transportation. It was impossible to drain the marshlands and the underlying soil would not have provided sufficient stability for roads. The ever expanding petrochemical industry, an important economic feature of the region for the last 60 years, used canals to move heavy equipment necessary for its functioning. This method has upset the natural ecosystem by allowing saltwater from the Gulf into the freshwater marshland, thereby removing an important natural safeguard against flood surges.
The mere fact of location makes settlement in New Orleans problematic. The situation was essential so the site had to work despite proclivity towards disease and flooding. Internal settlement patterns reflect these obstacles. Most of the city is at or below seas level. Until 1900, most settlement was on the natural levees, where the silt deposits made for stable inhabitance. Away from the river was swamp land and it was occupied by only the poorest residents.
Riverfront property was important and scarce. As a result, residents developed land holdings that looked like fans with a narrow portion on river that spread as it got further away from the banks. Because the river was not straight but winds through the city [Figure 10], boundaries fanned out or pinched in. To compensate, wide, tree-line boulevards were built as cross streets that were parallel to the river.
Settlement patterns changed drastically in the 20th century. Technology allowed for draining much of the swamp, a process that led to habitation between the river and Lake Pontchartrain [Figure 16]. This newly available land was technically open to all, but high prices and discrimination resulted in white only enclaves. After World War Two, the metropolitan area spread north of the lake and east and west of the city. A causeway across Lake Pontchartrain plus Interstate 10 opened new areas for suburban development. For those who stayed in the city limits, the flood plain cannot be avoided. Safety and survival depend on a massive canal and pumping system.
EFFORTS TO CONTROL ENVIRONMENT
There were risks in placing a city in such a precarious environment. There are two primary approaches to flood protection—structural and land use. The former entails constructing devices, such as levees, flood gates, flood walls and canals to both protect land and divert flood waters when they come. The latter is avoiding settlement on vulnerable land. The existence of New Orleans for over 300 years highlights the preference for structural solutions but residents had to prepare for the failure and/or inadequacy of those structures. Over time the most damage to New Orleans was not caused by the severity of storms but by the breach of flood walls or breaks in levees.
From 1920, the US Army Corp of Engineers (Corps) has been assigned the task of building structures to protect the city of New Orleans. The Corps has built floodgates to prevent levee breaches and channel flood waters into Lake Pontchartrain [Figure 17]. Another important task is drainage, both of the original swamp lands and the ongoing effort to keep pace with rainfall in low lying areas which is not always feasible. Draining swamp lands led to settlement in areas that are below sea level, placing more structures and residents in harm’s way when floods occur. The result, some observers say, is that residents have a false sense of security and are not prone to consider land use solutions. Increasingly, the Federal Emergency Management Agency (FEMA) is not happy about restoring those areas that are prone to flooding.
Building levees has worked for flood control but made the risks from hurricanes worse. The structures in place force the Mississippi to carry most of its sediment all the way to the Gulf of Mexico, rather than have its natural overflow build up the delta and sandbars, both of which serve as natural protection again storm surges after hurricanes. Before these levees were built, storms eroded the wetlands but the natural flow of the river restored them. The erosion continues, exacerbated by man made canals built through the delta but it no longer rebuilds itself. The CORPS understands this problem and knows that strategically employed floodgates can direct the river into planned sections of the back swamp and restore the wetlands but faces strong opposition from the seafood and industries as well as residential builders.
Besides the flood and hurricane related problems, New Orleans has to address problems of pollution, waste removal, and toxins. These have all increased a federal presence in the city as Washington established standards to be implemented and paid for by local authorities. These concerns have affected all US cities in the last few decades. One issue specific to New Orleans has been federal flood insurance guidelines, where FEMA establishes which areas are eligible for these safeguards. The last standards, pre-Katrina, were set in 1984. There had been a great deal of hope that the new guidelines, released in 2006 would deem certain areas no longer eligible, thereby establishing land use as the best means of flood protection. Instead, FEMA merely required that new and/or rebuilt construction be elevated three feet, well below the 20 foot surges that characterized the flooding after Katrina.
There is also the problem of cost. Who pays for these structural solutions? In the current age of air and motor transport, is it still imperative to have a city at the mouth of the Mississippi? Should the government pay to protect and/or rebuild in areas that are by their very nature subject to problems? These are unpopular and political untenable questions and few politicians seem willing to raise them. Particularly in New Orleans and Louisiana, localities known for fraud and inefficiency, some question whether tax dollars should continue to be spent or misspent on such potential folly.
“DON’T MESS WITH MOTHER NATURE”
New Orleans ultimate value to historians may be as a lesson in humanity’s ultimate ability to control the environment. One certainly must consider if the city will still be here at the start of the next millennium or even the next century. Or like its mighty river, will nature have the final say? Human nature and perhaps human hubris makes us believe we will prevail. Our infatuation with technology allows us to presume we have done so, yet Hurricane Katrina exposed the weakness of our design and implementation. It also underscored a political system that promises much and increasingly fails to deliver. There is no quick fix to the problems of New Orleans which were highlighted but not caused by the weather of late August 2005.
Just as the glory and folly of the city have extended past its boundaries from the beginning, so too will its fate. New Orleans was part of the great expansion and conquest that were the foundation of the United States. It encapsulates our arrogance, achievements, brilliance, creativity and limitations. It is an unattractive and unpalatable mirror that reflects the nation we have become rather than the nation we believe we are.
QUESTIONS FOR FURTHER RESEARCH AND DISCUSSION
- What is the difference between SITE and SITUATION?
Why are they incompatible in New Orleans?
- What will it take for residents to feel safe in New Orleans?
- How has technology been both a blessing and a curse in New Orleans?
- In what ways is the Mississippi River unusual?
What impact has this had on New Orleans?
RESOURCES FOR THIS ARTICLE
- Baum, Dan. “Letter from New Orleans: The Lost Year.” The New Yorker. August 21, 2006.
- Campanella, Richard and Marina. New Orleans, Then and Now. Gretna, LA: Pelican Publishing, 1999.
- Colten, Craig. An Unnatural Metropolis. Baton Rouge: LSU Press, 2005.
- Fitzpatrick, Tim. “New Orleans, Hurricane Katrina, and the Oil Industry.” Environmental Chemistry.com June 30, 2006.
- Lewis, Peirce. New Orleans: The Making of An Urban Landscape. Charlottesville: University of Virginia Press, 2003.
- Schwartz, John. “Engineers Faulted on Hurricane System.” The New York Times. July 11, 2007.