New study analyzed Landsat satellite imagery to document historical and recent (post-Hurricane Sandy) wetland changes that occurred along the Maryland and Virginia coastlines since 1984.
USGS scientists publish study documenting recent wetland-changes along Maryland and Virginia coastline
USGS scientists Julie Bernier and Kathryn Smith (SPCMSC) and Steven Douglas (Cherokee Nation Technologies) published a paper "Analysis of multi-decadal wetland changes and cumulative impact of multiple storms, 1984 to 2017" in the journal Wetlands Ecology and Management. This study analyzed Landsat satellite imagery to document historical and recent (post-Hurricane Sandy) wetland changes that occurred along the Maryland and Virginia coastlines since 1984. This study was part of the post-Hurricane Sandy Barrier Island and Estuarine Wetland Physical Change Assessment.
Land-cover classification analysis using Landsat satellite imagery acquired between 1984 and 2017 quantified short- (post-Hurricane Sandy) and long-term wetland-change trends along the Maryland and Virginia coasts between Metompkin Bay, VA and Ocean City, MD. Although there are limited options for upland migration of wetlands in the study area, regression analysis showed that wetland area increased slightly between 1984 and 2011, indicating that marsh aggradation rates were sufficient to maintain wetland elevation relative to mean sea level. Following Hurricane Irene (August 2011), the Halloween Nor’Easter (October 2011), and Hurricane Sandy (October 2012), wetland area decreased by more than 7 km2 compared with average pre-storm extents. We assume that Hurricane Sandy had the greatest impact due to the size and intensity of the storm. However, the cumulative effects of multiple storms within a short time period likely contributed to the greater observed losses in coastal wetlands relative to earlier periods. Five years after Hurricane Sandy, wetland area had not significantly recovered, but more time may be necessary to assess if the observed wetland losses will persist or if new growth within flooded marsh areas will be sufficient for the wetlands to recover to pre-storm extents. Comparisons of long-term and storm-driven wetland changes can lead to improved accuracy of habitat vulnerability models and greater understanding of potential impacts of future storms and SLR to coastal wetlands.
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