Field and Numerical
Investigations of Coastal Hazards and Nature Based Defenses From
Hurricane Storm Surge and Waves in the Chesapeake Bay
Juan Luis Garzon Hervas
George Mason University
11 June, Noon, in 2155
Abstract:
Coastal areas are frequently impacted by severe storms, resulting in
extreme damages to society and infrastructure. Moreover, this risk is
expected to increase under rising sea levels, climate change and
increased land development. In this dissertation, two main goals are
defined to support coastal resilience and protection against this
threat: 1) improve our ability to simulate coastal hazards in the
Chesapeake Bay; and 2) explore the effectiveness of natural defenses,
such as saltmarshes, in attenuating coastal hazards (storm surge and
waves). Firstly, the widely used numerical system ADCIRC+SWAN was
applied to explore the importance of numerical parameters, physical
processes and atmospheric forcing when implementing hydrodynamic models
in estuarine environments to simulate coastal hazards regionally.
Secondly, numerical modeling and a 3-year field-based monitoring
campaign documenting water levels, wave parameters and currents were
used to evaluate the ability of coastal ecosystems to mitigate floods
and attenuate waves. The analysis of measurements collected in two
saltmarshes in the Chesapeake Bay during several Hurricanes,
Nor’easters and other coastal storms demonstrated that 200–400m
marshlands can be a viable option for coastal protection against waves,
although they would be less efficient to mitigate high water depths
from storm surge. Furthermore, field-based analytical formulations to
predict wave height decay within the marsh were derived and validated
using different events. In addition, local scale numerical model
(X-Beach) simulations demonstrated that these predictive formulations
can properly replicate the wave height decay within other marshes of
the Chesapeake Bay. This study advances the scientific knowledge of the
coastal protection capacity of saltmarshes and provides reliable
numerical tools that can be used by coastal engineers to support
decision makers for adopting natural and nature-based coastal defenses.