Levee Failures and Social Vulnerability in the Sacramento-San Joaquin Delta Area, California

Abstract

This paper examines the spatial variability in the social vulnerability of residents to potential levee failures in the Sacramento Delta region. To determine the likely flood exposure, levees of concern to the U.S. Army Corps of Engineers and California's Department of Water Resources were mapped. The HAZUS-MH loss estimation software and 100-year protection standard were used to hypothetically breach levees to determine a coarse approximation of the level and spatial extent of inundation. To assess the differential social consequences of such an event, a social vulnerability index was computed at the census tract level for San Joaquin, Sacramento, and Yolo counties following the vulnerability metrics developed by Cutter et al. in 2003. When integrated with the flood exposure data, there is a clustering of high social vulnerability zones within high risk flood areas. While the spatial pattern is not uniform throughout the tricounty area, these pockets of high vulnerability ͑largely driven by social factors͒ warrant management concern about the disproportionate impact of catastrophic levee failures on these populations and the level of local, state, and federal preparedness to cope with such an event.

Debates—Perspectives on socio‐hydrology: Capturing feedbacks between physical and social processes

“…There is empirical evidence that flood control structures tend to promote an increase in the vulnerability (including exposure) of societies and, paradoxically, this often results in increasing flood risk [Burton and Cutter, 2008;Ludy and Kondolf, 2012]. An example is the case of New Orleans, where the process of building and raising levees has led to a shift from frequent, small flooding to rare, but catastrophic disasters [Kates et al, 2006].…”

‘Subjective resilience’: using perceptions to quantify household resilience to climate extremes and disasters

“…On the other hand, these same psychological and cultural elements also have a profound influence on household resilience. For example, cultural norms such as ethnic marginalisation will impact the ability of certain social groups to respond to disasters, perhaps through restricted access to key resources or economic marginalisation (Burton and Cutter 2008). Individual subjective traits, such as risk aversion or risk-taking, may also affect how a household chooses to respond to disaster risk and therefore influence their household's overall resilience.…”

Measuring 'Subjective Resilience': Using Peoples' Perceptions to Quantify Household Resilience

“…On the other hand, these same psychological and cultural elements also have a profound influence on household resilience. For example, cultural norms such as ethnic marginalisation will impact the ability of certain social groups to respond to disasters, perhaps through restricted access to key resources or economic marginalisation (Burton & Cutter, 2008). Individual subjective traits, such as risk aversion or risktaking, may also affect how a household chooses to respond to disaster risk and therefore influence their household's overall resilience.…”