Vertical land motion in Greater New Orleans: Insights into underlying drivers and impact to flood protection infrastructure.

Abstract

Vertical land motion is one of the main factors contributing to increased flood risk in coastal communities. Here, we use satellite interferometric synthetic aperture radar (InSAR) data to detect and measure previously undocumented land motions in Greater New Orleans (GNO), Louisiana. Although most of New Orleans is generally stable, rapid elevation loss occurs in parts of the city (up to -20 millimeters per year) and on flood protection walls constructed following Hurricane Katrina (up to -28 millimeters per year). This work provides unprecedented spatial coverage of land motion rates in GNO, including wetlands and the flood protection system previously lacking data, which allows a more detailed examination of ground deformation patterns and insight into underlying drivers. In the broader context, this work shows the potential of InSAR for measuring localized land motion in New Orleans and similar communities, particularly where the presence of wetlands complicates its application.