Identifying Erosional Trends of Upper Galveston Bay Salt Marshes from 2004-2018 High Resolution Imagery: A GIS and Remote Sensing Analysis
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Remote sensing has been a part of contemporary wetland conservation practices for many years. Data generated by aerial and satellite imagery has proven invaluable to assessing the health of wetland environments. Utilizing imagery of a certain location over the course of many years can produce a time series which can be used to observe visual changes in the environment throughout the observed range of time. With Geographic Information Systems (GIS), it is possible to record these changes in the marsh as vector features for future use in presentations or modelling. In a place like Galveston Bay, Texas, coastal salt marshes and residential or urban centers coexisting near one another are commonplace, so tracking the health of the marsh based on anthropogenic actions, both conservational and detrimental, is key to preserving them. In turn, the marshes preserve the communities they reside by through hazard mitigation and economic opportunity. In this research, years of high-resolution remote sensing data were used as a guide for the digitization of two salt marsh sites along the coast of Upper Galveston Bay. Through a series of geoprocesses, the area of wetlands lost for each site was calculated and the rates of loss were compared over time, and the relationship of vegetation loss and regional subsidence was investigated. Anthropogenic processes were also noted as timestamps to check effects on the marsh, like constructed upstream drainage or physical damage from traversal through the marsh. By comparing the digitized marsh edge over the years to the most recent elevation captured with LiDAR, the effects that anthropogenic processes have had on the wetlands became more tangible. Through these observations, a stark difference is presented between the erosion of natural and constructed salt marsh. Understanding the relationships between these wetland environments and the communities they neighbor will be an important piece of knowledge as climate change continues to alter the globe’s coasts.