MS Candidate, Auburn University
Conference Travel Grant Type 2
Determining Wetland Bathymetry with Sonar-Corrected Digital Elevation
Models
“Geographically isolated wetlands (GIWs) provide numerous ecosystem services across the southeastern coastal plain, such as water storage, wildlife habitat, and water filtration. Despite their importance, the hydrology of these depressional features is largely non-uniform. Obtaining accurate depth-area-volume relationships via bathymetric maps is a crucial first step in understanding many hydrologic variables in geographically isolated wetlands, such as direct rainfall capture and surface evaporation, volumetric recession rates, groundwater interaction, and depth-dependent flora and fauna. However, due to bathymetric irregularities characteristic of GIWs and regions of karst geology, traditional point surveys and correlations do not offer accurate solutions. Thus, the Deeper Smart Sonar CHIRP 2+ fish finder was used to take sonar depth measurements throughout three wetlands of focus, allowing for digital elevation models (DEM) with fine spatial resolution to be interpolated. As these wetlands are seasonally inundated, the accuracies of these sonar-derived DEMs were assessed with terrestrial lidar scans when the wetlands were dried down. The depth-area-volume relationships from the novel sonar method were shown to be more accurate both in magnitude and pattern when compared to correlations and point surveys. This method offers a quick and cost-effective way to obtain realistic depth-area-volume relationships for wetlands across the southeastern United States and, optimally, can be applied across a broader range of geographic areas and wetland types. We hope that these results will support forest management and wetland restoration by contributing to a more comprehensive hydrological understanding.”