The inundation of the City of New Orleans after Hurricane Katrina was a result of a number of failures of the levee and floodwall system. Some of these failures were directly attributed to erosion of the inside face, caused by substantial overtopping and overflow of surge and waves generated by the storm. The United States Army Corps of Engineers (USACE) recognized the significance of this overtopping and put in place a team to investigate and recommend methods of armoring; and to identify the most vulnerable locations.
In collaboration with USACE, Haskoning Inc. has recommended that the inside face (the floodside) be protected – or be resilient – against storm events which are in excess of the federally authorized 1% design standard. Haskoning Inc., using continually developing flood defense policy in the UK and the Netherlands, strove to define this concept of resiliency and how this can be practically implemented. With respect to armoring, this resiliency concept can be defined as designing the floodside face of the levee and floodwall system such that it will resist the erosive forces associated with extreme storm events, preventing catastrophic and sudden breaches.
On behalf of the USACE, Haskoning Inc. has adopted a leading role in the implementation and development of armoring solutions such that the floodside face will meet the criteria required to achieve “resiliency”. It has been recognized that the phenomenon of wave overtopping and its effect on floodside slope erosion processes are relatively unknown. A certain degree of confidence in such design theory is required to make the process practical to implement.
Haskoning Inc. is using its experience and worldwide contacts with the leading authorities and knowledge centers to identify, collate and disseminate practical guidance and recommendations. Haskoning Inc. is developing a methodology and design process which addresses and overcomes the theoretical obstacles associated with wave overtopping and erosion protection design.
To bridge the recognized knowledge gaps, i.e. the calculation of wave overtopping velocities and the development of performance thresholds for armoring materials has a high priority. Haskoning Inc. is working with the USACE to ensure that these knowledge gaps are bridged. This will be achieved by collaborative research and full scale testing. Through this programme of work, Haskoning Inc will work to ensure that the USACE is placed at the forefront of worldwide technologies and knowledge of wave overtopping protection.