5/21/2015

Black Swans, Brown River: How a Levee Failure Transformed Floodplain Restoration and Management in California's Central Valley – May 21, 2015. Presented by Dr. Joshua Viers ‡

Transformative events shaping human histories, perceptions, and modalities can be considered to be of the Black Swan variety. Black Swans, in this context, are unanticipated events with significant impact, yet in hindsight appear perfectly predictable. Flood events and ensuing social-ecological transformations are an archetype Black Swan. In this paper, we illustrate how a Black Swan event transformed not only a riverine floodplain, but also initiated a paradigm shift in thinking and approach to riverine floodplain restoration. In 1986, a relatively routine levee failure along the banks of the Cosumnes River led to the establishment of an “accidental” forest. The forest was not the surprise, rather it was the shift in thinking. In retrospect, of course, it was perfectly predictable that following the levee failure, floodplain restoration approaches would focus on initiating hydroecological processes, rather than on mimicking biological composition and pattern. Subsequently, the transformation in thinking has led to a scientific focus on ecological effects of hydrological process, including intentional levee breaching and promotion of flooded floodplains. We explore the role of Black Swans at the interface of ecosystem disturbance and human reaction within this emergent paradigm with a new focus on the use of setback levees and levee breaching to promote process-based restoration of Central Valley floodplains for multiple social-ecological benefits.

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