Abstract
Salt marshes are complex, vital ecosystems that provide numerous ecosystem services to humans. Much is still unknown about salt marsh dynamics and the ways in which hydrologic and hydrodynamic processes work in tidal wetlands. The one thing that has been clearly established is that the primary driver of salt marsh dynamics is elevation. The topography of the marsh determines water depth, how surface runoff moves through the marsh, the impact of waves and tides on the marsh, and even how plant communities form and interact with other elements of the marsh. Unfortunately, studying and monitoring the health of salt marshes is limited by their fragility. This study analyzes the use of Unoccupied Aerial Vehicles (UAVs), also known as drones, to assist with the study of salt marshes while attempting to limit human impact on the marshes. Through a series of case studies, this thesis evaluates the utility of digital aerial photogrammetry to study salt marshes and presents a set of best practices to be used in future studies. These include careful planning of flight paths, target locations, and launch points, as well as thorough pre-flight equipment checks and calibration, in-flight monitoring of imagery, and rescheduling of any flights which cannot be completed in a single day. The two methods of determining the accuracy of the digital surface model (DSM) produced are also analyzed and the results presented to inform best practices in future studies for post-data collection processing. While both CP and GCP processing have been shown to yield high internal, or relative, accuracy, the statistical analysis of both methods and their residuals shows that the elements of the models exhibiting high absolute accuracy can be quantified through a stability threshold calculated from the standard deviation of the residuals as a function of distance from site boundary and target zone.