LOW-ALTITUDE REMOTE SENSING APPLICATIONS FOR CRITICAL ZONE MANAGEMENT IN SOUTH CAROLINA, USA
Salt marshes are incredibly valuable ecosystems to the State of South Carolina. Despite this, salt marshes and other coastal wetlands are threatened by climate change, human encroachment, and both anthropogenic and natural forms of erosion. As a designated “critical area”, these regions are protected by state-level programs enacted through the passage of the Federal Coastal Zone Management Act of 1972. Statutory guidelines in South Carolina require computer-based inventories of its critical assets. Previously, a 2007 Critical Area inventory used specially acquired imagery and third-party GIS software to delineate low and high marsh zones. Technological improvements in imaging and digital mapping over the past ten years allow for quicker, almost instantaneous imagery production in small scale areas. This study assesses the use of both NAIP imagery and unmanned aerial vehicles for a precise, flexible, and cost-effective way of inventorying and assessing South Carolina’s coastal salt marshes. LiDAR fusion (imagery plus DEM) techniques were applied, having been shown to contribute positively in vegetation classification studies over recent years. This project was successful in inventorying salt marsh extent at a county-level. The use of drone imagery over areas of interest allowed for the quantification of previously misclassified marsh zones likely due to resolution concerns and mixed pixels. UAVs offer the ability to perform site-specific ecosystem assessments on-demand or at scheduled intervals with limited concern for atmospheric conditions. Using UAVs for wetland monitoring provides a low-cost method for restoration projects that get abandoned due to concerns about time or money.