Assessment of Hybrid Infrastructure Systems under Multi-Flood Hazards in
Coastal Georgia
Abstract
Tropical coastal communities accommodate critical infrastructure,
densely-populated urban regions, tourism-driven economies, and
industrial facilities. These communities are prone to multiple flood
hazards such as nuisance flooding, tropical cyclones, extreme rainfall
events, and sea-level rise (SLR). Thus, governments and stakeholders Are
pursuing a range of measures to enhance flood resiliency. These
alternatives can be classified into structural (i.e., conventional
infrastructure), non-structural, natural and nature-based features
(NNBF), and hybrid systems. While there is a large body of published
work on coastal risk reduction via conventional infrastructure and NNBF,
there is a paucity of information on Hybrid Infrastructure Systems (HIS)
in the literature, especially under multi-flood hazard scenarios. This
research aims to assess various HIS under multiple flood hazards for
flood reduction and wildlife and habitat benefits in the coastal
community of Tybee Island (Georgia, US). This community is the most
densely populated barrier island in Georgia and receives over 1 million
visitors each year. The Interconnected Channel and Pond Routing (ICPR)
hydrodynamic model was selected to simulate hydrologic (e.g., rainfall
and infiltration) and coastal (e.g., tides, storm surge, and SLR)
processes, and various combinations of HIS including several
conventional infrastructures (e.g., stormwater drainage system,
culverts, pump systems), inland (e.g., bioswales and pocket parks) and
coastal (e.g., horizontal levees and retention ponds with smart tidal
gates) NNBF. Results show that NNBF can prolong the service life of
conventional infrastructure in a HIS by reducing flooding stress on
these structures while promoting wildlife habitats and marsh
conservation by increasing the hydraulic connectivity in the tidal river
system. HIS alternatives were ranked using multi-criteria decision
analysis. The local government, residents, and stakeholders will select
their preferred alternative for detailed design. Local studies and
modeling of multi-hazard flood processes can provide insight into the
performance of HIS, thus providing the opportunity to policy-makers and
government agencies to improve design standards and permitting
procedures for HIS at a regional scale.