Risk to life due to flooding in post-Katrina New Orleans

Abstract

Abstract.Since the catastrophic flooding of New Orleans due to Hurricane Katrina in 2005, the city's hurricane protection system has been improved to provide protection against a hurricane load with a 1/100 per year exceedance frequency. This paper investigates the risk to life in post-Katrina New Orleans. In a flood risk analysis the probabilities and consequences of various flood scenarios have been analyzed for the central area of the city (the metro bowl) to give a preliminary estimate of the risk to life in the post-Katrina situation. A two-dimensional hydrodynamic model has been used to simulate flood characteristics of various breaches. The model for estimation of fatality rates is based on the loss of life data for Hurricane Katrina. Results indicate that -depending on the flood scenario -the estimated loss of life in case of flooding ranges from about 100 to nearly 500, with the highest life loss due to breaching of the river levees leading to large flood depths. The probability and consequence estimates are combined to determine the individual risk and societal risk for New Orleans. When compared to risks of other large-scale engineering systems (e.g., other flood prone areas, dams and the nuclear sector) and acceptable risk criteria found in literature, the risks for the metro bowl are found to be relatively high. Thus, despite major improvements to the flood protection system, the flood risk to life of post-Katrina New Orleans is still expected to be significant. Indicative effects of reduction strategies on the risk level are discussed as a basis for further evaluation and discussion.

Preface: Flood-risk analysis and integrated management

“…Floods following a dike breach can be especially disastrous and pose a risk to economic assets and life, given the potentially fast-rising water levels (Miller et al, 2015). The breach development process and the flow and sediment transport after a levee breach due to overtopping was examined by Dou et al (2014).…”

“…Also the contribution by Miller et al (2015) addresses the risk to life due to flooding in a delta area -in this case, New Orleans. Since the catastrophic flooding of New Orleans due to Hurricane Katrina in 2005, the city's hurricane protection system has been improved to provide protection against a hurricane load with a 1/100 per year exceedance frequency.…”

Modelación Hidráulica 2D de Inundaciones en Regiones con Escasez de Datos. El Caso del Delta del Río Ranchería, Riohacha-Colombia

“…Al proteger artificialmente a la comunidad, el riesgo de inundación es mayor, especialmente por la gran probabilidad que la obra falle (Miller et al, 2015). La obra tipo "dura" o convencional de protección a la comunidad, incentivarían más el urbanismo descontrolado alrededor de la protección espuria del dique, aumentando la vulnerabilidad de las viviendas expuestas a la amenaza latente de inundación con una mayor liberación de energía de colapsar el dique.…”

Lessons from analysing mortality from six major flood events in France(1930-2010)

“…loss of 1800 lives in Netherland on 31 January ± 1 February 1953 [2]; 1100 deaths after Hurricane Katrina in the state of Louisiana USA on 29 August 2005 [3]). Inland population can also be exposed to sudden flooding after flash floods, storms, dyke breaching or dam breaking.…”