Operational Prediction of Hurricane Induced Coastal Surge and Inundation

As a result of global climate change and sea-level rise, coastal regions are
increasingly vulnerable to wind-driven surge and inundation. Accurate and
timely forecasts of coastal inundation is necessary to assist in emergency
planning and humanitarian assistance to minimize adverse impact to affected
areas. The US Navy has hitherto used PC-Tides (Posey et al. 2008) for
operational predictions of coastal surge and inundation due to extreme tropical
systems and the Delft3D modeling suite (Stelling, 1996) for nearshore
circulation when inundation is not the primary concern. PC-Tides does not
include waves or other global ocean circulation and is also limited to a
maximum resolution of approximately 1km, which is insufficient for inundation
predictions (Hope et al. 2013). While the omission of the global ocean
circulation is likely to have minor impact on the surge and inundation levels,
the omission of waves has a significant effect on the water levels (Hope et al.
2013).

We will present the details of setting up the Delft3D system for predicting
surge and inundation due to tropical cyclones. The system comprises of the
coupled Delft3D-FLOW and Delft3D-WAVE components along with meteorological
forcing derived using the combination of forecasts and available best track
information for a particular storm system. The validation of the system will be
presented using Hurricane Ike as the example case. Hurricane Ike provides the
perfect base test to determine how well the system works because of the large
surge produced along the Louisiana-Texas coast, the large fore-runner surge
that tests the models physics and the large amount of data collected. We will
focus on the system response to various model inputs such as bathymetry
resolution and accuracy, changes in sea level and the impact of waves.