DETERMINATION OF SEDIMENT TRANSPORT FROM HURRICANE IDA (2021) ON DAUPHIN ISLAND, AL USING REMOTE SENSING

Dauphin Island, AL is exposed annually to numerous storm events. Such storms subject the barrier island to overwash events, habitat loss, and damage to infrastructure.

Barrier Islands play important roles in coastal geomorphology as the initial contact of storm surge. The dynamic environment in which they are found allows for rapid changes in island morphology over short timescales. Of which, the changing geomorphology for Dauphin Island involves the removal and transport of sediment. The volume of such sediment displaced before and after hurricane events has not been previously investigated, and thus leaves a gap in understanding the island’s morphologic changes with increasing frequency and severity of storms due to climate change. In this work, we aim to calculate the change in sediment volumes across Dauphin Island, AL by investigating pre and post Hurricane Ida barrier island change.

To do this, we will develop two geomorphic maps. The first will be indicative of pre- Ida Dauphin Island and the second post- Ida Dauphin Island. Using a regional-residual method, we can calculate sediment volumes of specific units along Dauphin Island, AL. These units will be divided into beach, dune, barrier flat, intertidal marsh and intertidal flat. The volumes of each individual unit will be calculated using remote sensing to determine the planimetric area of each unit divided into sections across the island. This coupled with DEM data allows for the volume calculation of each unit.

The first expected outcome is a geomorphic map of Dauphin Island, AL pre- Hurricane Ida in 2021. Similarly, the second is a geomorphic map of the island post- Hurricane Ida. The third expected outcome is the calculation of the volumes of beach, dune, barrier flat, intertidal marsh and intertidal flat. Such classifications may allow for interpretation of alternative sediment transport due to storm events. Additionally, this may illuminate potential regions that are particularly vulnerable to habitat loss from hurricane disturbance. Finally, this may benefit beach remediation projects that are ongoing to preserve Dauphin Island, AL by illustrating sediment transport needs.