Example - Cities and Hurricanes

Cities and heavily-urbanized areas in the path of hurricanes provide another example of resilience. Hurricanes inundate wide swaths of urban areas with water, only for the urban areas to be rebuilt. In theory, urban areas are rebuilt after the disturbance of each hurricane to be better protected against powerful hurricanes. Applying ecological resilience to hurricane management policy, we assume hurricanes to be a persistent, inevitable occurrence and design our cities and hurricane response plans accordingly. Unfortunately, hurricane damage has actually been exacerbated by the policy we have implemented from the mid-20th century to now. This policy is to build higher, stronger levees to keep floodwaters out and storm damage to a minimum.

New Orleans illustrates an overreliance on engineering solutions and the consequences of failing to apply resilience thinking. A hundred years ago, New Orleans was hit by a series of hurricanes, after which it decided to invest in structural upgrades to prevent future flooding (Colten and Giancarlo 2011). The structures’ effectiveness was tested in the 1940s, and though it did reduce damage to the city center, suburbs that had grown beyond the seawall and levees were heavily impacted by the storm. Post-storm analysis determined that the suburbs could also be protected from heavy flooding through a more extensive levee system, but other factors had also mitigated storm damage. For example, one of the worst affected areas, east of the city, did not have residential or commercial development and effectively functioned as a buffer. Traditional housing construction methods, which put houses up on tiers two or more feet above ground, were also contributed to flood prevention (Colten and Giancarlo 2011).

The city nonetheless went all-in on levee construction, even as the city expanded into low-lying wetlands and other flood-prone areas. With levees in place, housing construction switched to cheaper and more popular methods. City officials, confident that the new levees could withstand previous hurricanes, largely discounted flooding threat. Even as subsequent hurricanes struck, including in Hurricanes Betsy, Camille, and Katrina, the philosophy of rebuilding stronger and better has remained, with the baseline for adequate protection shifting to the strength of the most recent hurricane in societal memory. This philosophy epitomizes engineering resilience, where the metric is how quickly the system can bounce back to its prior state (Angeler and Allen 2016). Ecological resilience requires an understanding of the adaptive cycle as well as a holistic approach: how can we use collapse and reorganization, through policy, science, and engineering, to minimize the consequences of persistent, inevitable hurricanes?

Photographs before and after Hurricane Katrina in Bay St. Louis, Mississippi show the destruction of the coastal structure on the border of the city, as well as massive damage to the city itself. Photo Credits: U.S. National Oceanic and Atmospheric Administration, available under the public domain

References

Angeler, D.G., and Allen, C.R. 2016. Quantifying resilience. Journal of Applied Ecology, 53: 617-624.

Colten, C.E., and Giancarlo, A. 2011. Losing resilience on the gulf coast: hurricanes and social memory. Environment: Science and Policy for Sustainably Development, 53(4): 6-19.