Coastal communities are threatened by many hazards, such as storm surge, flooding, saltwater intrusion, and coastal erosion. A tide gate at Hunter Army Airfield in Savannah, GA, has a history of failure and repair that has caused numerous ecological shifts to the low-lying vegetation located between the tide gate and a critical rail line upstream. Field surveys and a hydrodynamic model were used to determine the effects of the tide gate on the surrounding marsh and to quantify how these landscape changes translate into the performance of the marsh ecosystem as natural infrastructure. Four scenarios (natural, present, potential, and damaged conditions) were used in a hydrodynamic model to identify potential issues, including tide-gate overtopping, increased erosion risk, and extended flooding due to flow constrictions. In conclusion, this research helps understand the implications of how traditional infrastructure disrupts ecosystem function and the trade-offs between engineered and natural coastal defense systems.
