IPET Report 3 Vol VIII

Figure 14. The Individual Hurricane Paths Considered in the Risk Analysis
Calibration and Extension of the MR Results Using the HR Runs
For the high resolution subset of the MR runs (the HR runs) the final water levels are taken
directly from the simulations. However, for the remainder of the MR cases, it was necessary to
make corrections to adjust for a relative lack of resolution of the MR grid. These corrections are
site-specific, depending on the local geometry of the coast, the topography, and the different
local land coverage of the MR and HR grids. The correction further depended on the hurricane
parameters; in particular, the correction at a given location will generally depend on landfall
position X, direction θ, and possibly storm intensity ΔP and radius to maximum winds, Rmax.
The calibration procedure applies to locations at which the MR grid produces realistic
results. At locations where this is not so, for example along narrow canals where the MR values
are not reliable or may not exist (because the MR grid does not extend to those locations), a
different strategy was used. For this case, HR results were used to fit regression relations in
terms of values along the coast where the MR solution is available. Then fitted regressions were
used to extrapolate the estimates from preceding corrections. The calibration process is described
in detail in Appendix 8.
VIII-36 Volume VIII Engineering and Operational Risk and Reliability Analysis
This is a preliminary report subject to revision; it does not contain final conclusions of the United States Army Corps of Engineers.