Southeastern Section - 68th Annual Meeting - 2019

Paper No. 48-6
Presentation Time: 3:55 PM

MAPPING SUBMARINE GROUNDWATER DISCHARGE USING A THERMAL INFRARED SENSOR MOUNTED ON AN UNMANNED AERIAL SYSTEM IN COASTAL NORTH CAROLINA, USA


MOORE, Raymond1, GHONEIM, Eman M.2, WELLS, Dave1 and ZAMORA, P.B.3, (1)University of North Carolina Wilmington, 5208 Fox Court A, Wilmington, NC 28405, (2)Geography and Geology Department, UNCW, 601 South College Road, Wilmington, NC 28403, (3)Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC 28403

Submarine groundwater discharge (SGD), the direct discharge of groundwater from coastal aquifers to the ocean, is an important fresh water and dissolved nutrient source in Onslow Bay, NC. Hence, mapping SGD hotspots and hot moments is important to better understand their impacts to coastal waters. Here we applied innovative geospatial analysis techniques using thermal infrared (TIR) data from a multispectral satellite and a senseFly eBee equipped with multiple sensors to map SGD anomalies, with high accuracy over a vast areal extent. In-situ radon, temperature, salinity, and global positioning coordinates were measured during the survey for data validation. Relative to commonly used chemical tracing techniques, utilizing geospatial analysis of TIR and multispectral data enables a more cost-efficient, spatially-accurate, and time-efficient method for monitoring SGD. Survey results from Masonboro Barrier Island revealed cooler sea surface temperature anomalies adjacent to the wider section of the barrier island where more groundwater can potentially accumulate and discharge along the island shoreline. High 222Rn concentrations in seawater adjacent to this site confirms the presence of SGD. The average groundwater discharge within a tidal cycle at this site is 0.78 m d-1. This approach demonstrates the utility of UAS-TIR systems in mapping SGD hotspots and potentially hot moments in coastal areas such as barrier islands.