Dr. McKenna's primary research and service is within the field of hydrogeology with a focus on the water resources of Delaware. General research topics include ground-water/surface-water interaction, aquifer characterization, heat transport, and the evaluation of the quantity and quality of water resources. Research consists of field and modeling studies using optical and thermal remote sensing from satellite, aerial, and ground-based platforms, surface and borehole geophysics, time-series and spatial analyses (GIS), and modeling of ground-water flow and heat transfer. Heat is used as a tracer of hydrologic processes and as a proxy for hydrologic and thermal properties.