Year Established: 2019 Start Date: 2019-05-31 End Date: 2020-05-30
Total Federal Funds: $2,000 Total Non-Federal Funds: $880
Principal Investigators: Jesse Bunker
Abstract: River temperature patterns and using heat as a tracer to study groundwater surface water interactions is well documented in the literature (eg. Ward, 1985; Hare et al., 2015). The Greater Yellowstone ecosystem hosts mountainous terrain and thousands hydrothermal features that interact with rivers of various size and geomorphology (Hurwitz et al. 2007). Hydrothermal mixing in rivers can alter temperature and chemical regimes and has ecological and biogeochemical implications (Cardenas et al., 2011). Yet, the spatial and temporal variability of hydrothermal features and their interactions with rivers is not well understood. It is well agreed upon by ecologists that spatial heterogeneity generally promotes species biodiversity and can provide habitat for specialized biota (Allan & Castillo, 2007; Rosenberry et al., 2016). Wildlife are also known to exploit thermal features; in winter months elk congregate in geothermally modified basins to reduce the stress of deep snowpack (Garrott et al., 2002). In aquatic environments salmonids congregate in areas of groundwater discharge where water is cooler than the rivers bulk flow (Breau et al., 2007). Sources of habitat heterogeneity in rivers within the Greater Yellowstone ecosystem can come from groundwater discharge and hydrothermal features. The presence of cold water refugia were found to be highly temporally and spatially variable (Dugdale et al, 2013). Hydrothermal water mixing in Yellowstone National Parks Fire Hole river was shown to give rise to thermal spatial variability due to long mixing zones (Cardenas et al., 2011), however temporal variability has not yet been investigated. La Duke hot spring is a developed hydrothermal feature that discharges into the Yellowstone River and has been monitored by the Montana Bureau of Mines and Geology since 2005 as part of the Yellowstone Control Groundwater Area. As a result, La Duke hot springâ€™s temperature and chemical characteristics are well documented throughout the year. Less well documented are the hydrothermal features that appear adjacent to La Duke hot spring. These features extend along the east bank of the Yellowstone River from La Duke to roughly a half-mile upstream. The size and geomorphology of Yellowstone River is distinct from that of the Fire Hole River and offers an opportunity to compare hydrothermal feature river interactions at disparate scales. An ongoing study (Crowley et al., ongoing) is using an unmanned aerial vehicle (UAV) mounted with optic and forward looking infrared (FLIR) cameras to quantify the spatial extent and variability of La Duke and adjacent hydrothermal features as well as their interaction with the Yellowstone River. While using a FLIR camera mounted on an UAV offers the advantage of collecting data with high spatial resolution over moderate distances, it has limitations. FLIR cameras are only able to measure the temperature of the upper 1mm of the water surface, meaning a hydrothermal feature will only be quantifiable if its thermal signature reaches the water surface. During this ongoing study researchers found areas of the river bed with a thermal signature that does not affect the upper 1mm of the river water throughout the year. Quantifying hydrothermal input from these areas is equally important for understanding the temporal variability of this hydrothermally modified section of river.