Academic journal article Duke Environmental Law & Policy Forum

United States Flood Control Policy: The Incomplete Transition from the Illusion of Total Protection to Risk Management

Academic journal article Duke Environmental Law & Policy Forum

United States Flood Control Policy: The Incomplete Transition from the Illusion of Total Protection to Risk Management

Article excerpt


A. The Transition From Passive Adaptation to Maximum Protection

A flood occurs when water overflows a river or a lake and covers land that is not normally submerged. Floods are an inevitable function of the hydrologic cycle, and flood cycles were originally seen as blessings because they sustained riverine ecosystems and the floodplain economies dependent on them. Floods became a social problem only when they did not occur. However, as more people settled in floodplains, floods transformed into a social problem because they both disrupted agricultural production and caused extensive damage to settlements. Floodplain dwellers soon expected governments to reduce or prevent flood damages through hydrologic engineering. The construction of dykes to halt the spread of flood waters and increase the current to flush silt downstream dates back to at least the eighth century CE in China. (1) Roman-raised embankments in the Fens lasted until the eighteenth century in England. (2)

Until the mid-twentieth century, the story of modern flood control was the transition from adaptation to the inevitable to an expectation that government would provide maximum flood prevention and generous post-disaster relief for floodplain dwellers. For the last sixty years or so, the story has been the growing recognition, especially as the understanding of climate change has increased, that the goal of maximum protection is unobtainable because flood damage is an inevitable risk that can only be managed, but never totally avoided. Thus, we are now making the transition to the idea that we must manage floodplains through a combination of structural defenses, upstream storage, and land-use controls. (3)

This transition to integrated floodplain management will be a painful and controversial process because the expectation that we can outsmart nature through maximum flood prevention is deeply embedded in our thinking about floods. Three powerful and related scientific, technological, and ideological nineteenth century developments contributed to this expectation.

First, the science of hydrology developed rapidly in the nineteenth century. (4) The new understanding of water's behavior, along with the development of new engineering technologies enabling construction of large dams, increased the options for flood control. Second, these scientific and engineering developments reinforced the belief, rooted in ancient Greece, (5) that humans should use our understanding of nature to improve upon her imperfect processes by controlling them when they threaten to impede human activity? Third, a powerful, central state gradually became accepted as the entity to control nature, and thus promote human progress. (7)

Beginning in the 1860s, these trends led to a policy of maximum flood prevention. (8) The rub is that the assumptions on which the policy is based no longer hold in their original form. However, the United States has not found a coherent replacement for maximum flood protection. For example, since 2006, the federal government has spent $14.5 billion on a post-Katrina flood protection system for New Orleans, although the 133-mile chain of levees, flood walls, gates, and pumps still puts the city at risk because it is based on the outmoded concept of the 100-year flood. (9)

B. The Demise of Maximum Protection

Engineers have long promised floodplain dwellers that structural measures such as levees, dykes, and upstream storage reservoirs can substantially prevent flood damage. Students of flood policy know that promise to be illusory for four basic reasons. First, global climate change has undermined many of the fundamental hydrologic assumptions upon which flood control, from levee construction to reservoir management, is premised. Hydrologists have long assumed that they could predict with considerable accuracy the frequency and scale of floods. …

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