Leslie F. Harder

Investigation of the performance of the New Orleans regional flood protection systems during Hurricane Katrina: Lessons learned

The recent flooding and devastation of the greater New Orleans region during hurricane Katrina represented the most costly peace-time failure of an engineered system in North American history. Extensive investigations and analyses have been performed by several major teams in the wake of this disaster, and some very important lessons have been learned. Many of these have very direct and urgent applications to levee systems in other regions throughout the U.S., and the world. Lessons include the importance of proper evaluation of risk and hazard; so that appropriate decisions can be made regarding the levels of expense and effort that should be directed towards prevention of catastrophe, and the levels of post-disaster response capability that should be maintained as well. The making of appropriate decisions, given this information regarding risk levels, is then also important. Also of vital importance are numerous “engineering” lessons regarding analysis, design, construction and maintenance; hard-won lessons with applications to flood protection systems everywhere. We must now do everything possible to capitalize upon these; and to prevent a recurrence of this type of catastrophe in the future. 1 Professor, Dept. of Civil and Environmental Engineering, University of California at Berkeley, Berkeley, California 94720. Email: seed@ce.berkeley.edu GSP 161 Embankments, Dams, and Slopes Copyright ASCE 2007 Geo-Denver 2007: New Peaks in Geotechnics Redistribution subject to ASCE license or copyright. Visit http://www.ascelibrary.org

Investigation of levee performance in Hurricane Katrina: The inner harbor navigation channel

The Inner Harbor Navigation Channel (IHNC) sits at the heart of the three main populated regions of New Orleans. As shown in Figure 1, a number of breaches of varying severity occurred along the shores of the IHNC during Hurricane Katrina, contributing to the flooding of all three of the most heavily populated protected areas flooded in this event. This paper presents the results of geotechnical and geo-forensic investigations performed to determine the causes of the various failures along the shorelines of the IHNC. This includes the two massive breaches at the west end of the Lower Ninth Ward, and a number of lesser breaches and partial breaches (distressed sections) along other sections of the canal. There are many lessons here, not just for the greater New Orleans region, but for the nation and for the Profession as well.

Effects of Borehole Fluid on Standard Penetration Test Results

The standard penetration test (SPT) represents the most widely used in-situ test method for evaluating the liquefaction resistance of saturated soils. Significant progress has been made in recent years in developing correlations between SPT results obtained using different test procedures and equipment in order to develop a higher degree of standardization for SPT testing. One of the heretofore unresolved factors affecting SPT results is the effect of borehole fluid type (for example, water or drilling mud). This paper presents a study in which field data were obtained from SPT performed in adjacent boreholes, some filled with water and others filled with drilling mud, at four different sites in order to investigate this effect. A total of 213 SPT were considered: 147 SPT in mud-filled boreholes and 66 SPT in water-filled boreholes. Borehole fluid type (drilling mud versus water) was found to have no significant effect on STP resistances measured so long as careful and appropriate drilling and sampling procedures are employed.