Prepared by Anne Dalke
Additions, revisions, extensions are encouraged in the Forum
Catherine's work, which focuses on the "top end" of river systems, and Rheanna's studies as a cities major and geology minor intersected here in a "crossover geopolitical" presentation, which took place just as the levees in New Orleans were being over topped again by Hurricane Rita. Catherine began by observing that the claim of governmental officials that "no one could have predicted this" were "just not true." New Orleans has long been used in introductory geology classes as a classic example of the conflict between nature and culture; in The Control of Nature, the well-known environmentalist John McPhee describes the time bomb of the Mississippi Delta"; and in 2002, The Times-Picayune did a five-part series on the flooding hazard in New Orleans.
To demonstrate the inherently fragile nature of a river delta, Catherine presented a number of elevation maps of the Gulf coast. New Orleans is a "bowl" lying between Lake Pontrachain and the Mississippi River, which are above sea level (ironically, the banks of the Mississippi are the highest ground in the city, and served as barriers to protect some of the lower-lying areas from flooding). Catherine also provided a review of the "forensic geology of the past week." The initial analysis is that the levees were overtopped; designed for category 3 storms, the levees could hold back 11 1/2 feet of water, but the water line reached just above that, to 12 feet. The initial remedy was to make more breeches in the levees, in order to allow the water to drain out of the affected neighborhoods.
Humans have dramatically changed the distribution of sediment in the Mississippi River system. Catherine explained that nothing had been done to counteract the natural action of sediment compacting under its own weight. In fact, pumping water out of an area--as is done continuously in New Orleans--exacerbates the natural process, perhaps by as much as 10x the natural rate. The levees also prevent new sediment from being deposited. The wetlands are eroding rapidly, as are the barrier islands. Natural disasters are primarily disasters, in other words, because of how humans interact with nature. Our stubbornness exacerbates natural processes. "Thinking geologically," not emotionally, or in terms of culture, "this is not the best site for a city."
Rheanna observed that official calls for protecting New Orleans from a "worst case scenario" cannot be answered. "If we believe in climate change, we don't know what is coming." What we can do, however, is maximize the flexibility of the human population. The poor are always the first and the most affected by natural disaster. Rheanna shared some census maps to illustrate the maldistribution of income in the city. We need to find ways to raise the socio-economic level of those living in New Orleans (The poverty level is 12/4% in the U.S.; 27.9% in Louisiana; 36.4% in New Orleans. Why is the city so poor? What is the relationship of the poverty level to levels of segregation in the city? In the state? In the south?)
The "big picture question," of course, is how we can rebuild a viable city, and the structure of a stable economy, in the dynamic geographical system that is the Mississippi Delta. Constructing a permanent civilization in an area that is geographically dynamic means investing in a number of activities that are fundamentally at odds: flooding, for instance, which endangers neighborhoods, is what keeps wetlands healthy.
Several of the participants in the discussion were New Orleans natives, who described the increasing height of the levees, the increasing spread of development, the "ever-present sense of risk" of danger from flooding, and the "disconnect" between science and the insurance policies available to city residents; the matter of "risk assessment" was very poorly handled.
Discussion then turned to potential solutions. Can people learn to develop more flexible cultural arrangements, instead of trying to re-build New Orleans as a fortress? We knew flooding would happen, and we know it will happen again. We can ignore the danger, withdraw from it, or redesign the culture. Can we retrofit buildings? Rather than spending money to build increasingly concentrated pockets of wealth, can we re-build the city in a more flexible form? What degree of social control is desirable? Given the the inevitability that people will return, and given the vast scope of instability in the region,how much of such design is "just tinkering"?
Catherine closed the discussion by distributing copies of a 2001 Scientific American article by Mark Fishetti, "Drowning New Orleans. Participants were invited to continue the discussion next Wednesday morning when the Emergence Working Group meets in Park 230, and Tim Burke of the Swarthmore History Department will lead a discussion of "The Emergence of Emergencies." Further discussion also continues in the brown bag on-line forum area.
Next week, on September 30, this series will continue with Peggy Hollyday (Biology) encouraging a conversation about a series of
recent news events that contribute to sharpening ongoing discussions about
women and science. These include the speech given last winter by Harvard
President Lawrence Summers, a Los Angeles
Times letter to the editor by CalTech President David Baltimore, in which
he discusses the declining position of American science in the global
economy because too many scientists want "balanced lives", and a recent New York
Times article titled "Many Women at Elite Colleges Set Career Path to
Motherhood" (September 20, 2005).