Performance Evaluation of the New Orleans and Southeast Louisiana Hurricane Protection System: Draft Final Report of the Interagency Performance Evaluation Task Force, Volume II - Geodetic Vertical and Water Level Datums [open pdf - 6MB]
"The primary focus of this study was to identify a common vertical reference framework for the various IPET [Interagency Performance Evaluation Task Force] physical models and high-resolution hydrodynamic models developed on this project. The common vertical reference framework chosen was the North American Vertical Datum of 1988--actually the 2004.65 adjustment to this datum (NAVD88 (2004.65)). This framework was adopted in order to relate flood control and hurricane protection system elevations to the local water surface reference datum used in hydrologic, hydraulic, flood inundation, and risk assessment models, e.g., local mean sea level, river low water reference planes, etc. Controlling elevations on floodwalls, levees, pump stations, and bridges through the SE Louisiana region were surveyed relative to this geodetic framework. This geodetic framework was intended to provide a consistent, or common, reference system for numerical and physical model studies, interior drainage models, and hydrodynamic models in the IPET study region. In addition to developing this basic framework, an evaluation was made of changes in flood/ hurricane protection resulting from elevation changes (i.e., net land subsidence and sea level rise) throughout the region. This entailed comparing flood/hurricane structure protection elevations (and reference datums) at the time of original design/construction with the current elevations ('pre-Katrina')."
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