However, the group also cautioned that until the risk assessment portion of IPET's analysis is complete, fully informed long-term development and safety decisions cannot be made for the city of New Orleans.

Risk Quantification Essential for Improving Hurricane Protection System

While expressing overall satisfaction with the technical competency and findings of the draft final version of the United States Army Corps of Engineers (USACE) Interagency Performance Evaluation Task Force’s (IPET) report, Performance Evaluation of the New Orleans and Southeast Louisiana Hurricane Protection System, the American Society of Civil Engineers’ (ASCE) External Review Panel (ERP)—a group organized to provide peer review of the IPET’s work—today cautioned the USACE that until the risk assessment portion of their analysis is complete, fully informed long-term development and safety decisions cannot be made for the city of New Orleans. Despite this urgent need for the risk assessment findings, the ERP also cautioned that work must be completed to a high level of defensibility before being released to the public.

“Over the course of our year-long review of the Corps’ investigation, the ERP has not identified any IPET finding that we believe contains a major technical flaw,” said ERP Chair David E. Daniel, Ph.D., P.E., president of the University of Texas, Dallas. “However, due to its extreme importance to the public’s ability to decide if they feel it is safe enough to live in New Orleans, we continue to be concerned that the risk assessment portion of the analysis has yet to be completed.”

The ERP expressed their agreement with the IPET’s key findings in the final draft report. However, noting that multiple, ill-fated decisions made at nearly every level were the overall cause of the breaching and resulting flooding, the ERP advised that additional information on ‘why’ those decisions were made—while outside of the IPET’s scope of work—would be essential to understanding the impact those decisions had on various parts of the system. The ERP also challenged the use of the word “marginal” in the statement, “The designs for these structures were marginal with respect to practice…,” which they believe minimizes significant information documented by the IPET suggesting that serious design mistakes were made. And, while the ERP believes it would be appropriate for the IPET to acknowledge where it found as-constructed conditions to be in agreement with the design documents, the report’s statement that “there was no evidence of government or contractor malfeasance,” is a judgment beyond the IPET’s scope of work.

As a result of the IPET’s in-depth investigation and assessment, the ERP has noted numerous significant recommendations and processes that have been developed. However, the value of the substantial work done will only be realized if there is immediate implementation of the report recommendations. For example, if a commitment isn’t made to establish ongoing monitoring programs to assess the impact of subsidence on hurricane protection design and construction, the IPET findings will only constitute a snapshot in time. Also, while the ERP was satisfied with the hydraulic and hydrologic models developed by the IPET in the context of the draft final report, the maintenance and use of those models in conjunction with the risk model is critical to the long-term protection of New Orleans, and as a result the ERP expects this issue to be addressed in the group’s final report.

Finally, the ERP expressed concern with the report’s clarity, consistency and the accessibility of the information to readers who are not as intimately knowledgeable of the system as the IPET and ERP members. This report will not only serve as the definitive record of what happened and why as a result of Hurricane Katrina, but its findings will also significantly impact the decision making process for development in New Orleans—and perhaps other flood prone parts of the country. As a result, it is essential that the information be consistently presented in a format which makes it accessible and understandable.

Throughout the year-long process, the ERP has commended the USACE for subjecting its technical work to detailed external scrutiny by independent reviewers, and has appreciated the constructive and professional manner in which the ERP and the IPET have been able to interact. The ERP believes this process has served the citizens of New Orleans and Southeastern Louisiana, the USACE and the nation well in understanding the causes of and consequences from the catastrophe brought on by Hurricane Katrina.

Source : ASCE.org