USING LIDAR DATA TO DOCUMENT ELEVATIONAL CHANGES IN RESTORED URBAN COASTAL WETLANDS

Jamaica Bay (New York, NY) is a hypereutrophic, urban estuary that has lost over 92% of its historic wetland area over the past century. As a consequence, it has been the site of a series of large-scale (40 acre) marsh restorations over the past two decades. Whether these restored marshes will remain stable long-term and provide the same ecosystem services as natural marshes remains an open question. The goal of this project is to document changes in elevation for the wetlands in Jamaica Bay to determine whether the marshes are keeping pace with sea-level rise or experiencing subsidence. Here we focus on two large-scale marsh restorations: Elders East, which was completed in 2006, and Yellow Bar, which was completed in 2012. Using publicly available LiDAR data collected between 2008 and 2020, we determine how elevations of the marsh platform and marsh edge, relative to mean sea level, have changed over time following initial restoration. We compare changes in elevation in these two restored marshes to JoCo, an unrestored marsh in Jamaica Bay that has remained relatively stable for the past 50 years, and Black Bank, an unrestored marsh that has declined rapidly in both stability and total extent. The period of available LiDAR data includes two major disturbance events, Hurricane Irene and Superstorm Sandy. Superstorm Sandy occurred 6 years after the completion of Elders East and directly following the completion of Yellow Bar, providing us with a rare opportunity to document the elevational responses of two young marshes to a major disturbance event. The results of this project will complement ongoing interdisciplinary efforts to document the efficacy of coastal marsh restoration efforts in New York and throughout the Northeastern United States.