Abstract
Flood risk assessment is primarily performed by a single flood driver at
a specific location. A significant flaw in this approach is the
oversight of the nonlinear interactions between various flood drivers
(e.g., river flooding, tides, storm surges, and fluvial regimes),
potentially resulting in compound flooding. This oversight can lead to
underestimating the socioeconomic consequences of compound floods, which
often surpass the risks posed by individual drivers acting alone. This
study employs a deep learning model, mainly Long Short-Term Memory to
predict water levels in tidal rivers under the influence of various
flood drivers. The model is used to predict water levels at specific
locations, using upstream river discharge, downstream water levels, and
initial water levels as input variables. To account for
coincidence/concurrence of drivers, we use Copula functions as a
probabilistic approach to model the correlation between peak river
discharge and coastal water levels as input features for the DL Model.
The application of the proposed method is illustrated by applying it to
a case study in the Buffalo Bayou area near Houston, TX. The results
show that, for a 50-year flood, considering prior water level conditions
represented by the 10th and 90th percentile baseflow scenarios, the
projected flood inundation area can vary significantly, ranging from
30% to 70% for the same return period. The proposed methodology
advances flood hazard assessment in coastal regions by capturing the
complex interplay of different flood drivers and offering a robust yet
practical flood inundation mapping approach.