Variations in water temperature and implications for trout populations in the Upper Schoharie Creek and West Kill, New York, USA

Abstract

Water temperature is a key component of aquatic ecosystems because it plays a pivotal role in determining the suitability of stream and river habitat to most freshwater fish species. Continuous temperature loggers and airborne thermal infrared (TIR) remote sensing were used to assess temporal and spatial temperature patterns on the Upper Schoharie Creek and West Kill in the Catskill Mountains, New York, USA. Specific objectives were to characterize (1) contemporary thermal conditions, (2) temporal and spatial variations in stressful water temperatures, and (3) the availability of thermal refuges. In-stream loggers collected data from October 2010 to October 2012 and showed summer water temperatures exceeded the 1-day and 7-day thermal tolerance limits for trout survival at five of the seven study sites during both summers. Results of the 7 August 2012 TIR indicated there was little thermal refuge at the time of the flight. About 690,170 m 2 of water surface area were mapped on the Upper Schoharie, yet only 0.009% (59 m 2 ) was more than 1.0 C below the median water surface temperature (BMT) at the thalweg and no areas were more than 2.0 C BMT. On the West Kill, 79,098 m 2 were mapped and 0.085% (67 m 2 ) and 0.018% (14 m 2 ) were BMT by 1 and 2 C, respectively. These results indicate that summer temperatures in the majority of the study area are stressful for trout and may adversely affect growth and survival. Validation studies are needed to confirm the expectation that resident trout are in poor condition or absent from the downstream portion of the study area during warm-water periods.

Assessing the potential of drone‐based thermal infrared imagery for quantifying river temperature heterogeneity

“…Other potential uses include assessment of thermal effluent from power plants (required under the U.S. Clean Water Act and the EU Water Framework Direct; Miara, Pienkos, Bazilian, Davis, & Macknick, ) and dams. Alongside human impacts, there is also recent interest in TIR for mapping potential cool water refuges used by freshwater species to avoid heat stress (e.g., Frechette, Dugdale, Dodson, & Bergeron, ; George, Baldigo, Smith, McKeown, & Faulring, ; Wawrzyniak et al, ); identifying these refuges is crucial in light of projected climate change. sUAS‐based TIR would be advantageous in smaller or remote river systems where “conventional” airborne TIR is too costly and traditional in‐stream measurements risk missing local spatial variation.…”

“…We were also surprised that TIR was unable to accurately quantify the difference between plume and main stem temperature during the July 2017 survey of Onondaga Creek (given this analysis was conducted using a single image and is hence unaffected by interimage temperature drift). The poorer performance of TIR in July may result from differences in mixing of the cooler plume water between May and July, due to either changes in flow/velocity between the two surveys or the increased temperature difference between the main stem and inflow (in comparison with May), which can cause the cool inflow to "plunge" underneath the warmer main stem water mass due to its reduced buoyancy, thus complicating its measurement at the surface using TIR (e.g., Handcock et al, 2006 impacts, there is also recent interest in TIR for mapping potential cool water refuges used by freshwater species to avoid heat stress (e.g., Frechette, Dugdale, Dodson, & Bergeron, 2018;George, Baldigo, Smith, McKeown, & Faulring, 2016;Wawrzyniak et al, 2016); identifying these refuges is crucial in light of projected climate change.…”

A practitioner's guide to thermal infrared remote sensing of rivers and streams: recent advances, precautions and considerations

“…Provided mixing is sufficient, the logger installation depth (i.e., anchored to the bed or suspended from a buoy) will not significantly influence the recorded temperature (SJD, unpublished results). Loggers are also often installed within piping or plastic tubing to ensure that they are not influenced by solar radiation nor damaged by collisions with in‐stream debris . The spatial distribution of loggers depends on the scale and resolution of the study and is governed by accessibility; logger densities between 0.02 and 0.45 km −1 have been reported in the literature .…”

“…In light of the threat posed by climate change to fluvial environments, emphasis is increasingly being placed on the need for better understanding of river temperature dynamics . River temperature is often considered the ‘master’ variable controlling all chemical and biological processes within the river channel and, as such, plays an important role in governing the habitat niches of many aquatic species. River temperature is also an important indicator for a range of physical habitat processes (e.g., mixing and flow velocity, ice cover/thickness, groundwater–surface water exchange and pollutants), and a better insight into the thermal regimes of rivers is therefore key to understanding the both the ecological and physical composition of fluvial environments.…”

Airborne thermal infrared videography of stream temperature anomalies from a small unoccupied aerial system

“…As sUAS technology has continued to advance, lighter sensor payloads have been developed that can now be integrated with sUAS for collecting both visual and multispectral imagery. Of these, a specific type of imagery, thermal infrared (TIR), can be used to image water bodies to assess surface temperature (e.g., Briggs, Hare, Boutt, Davenport, & Lane, 2016;George, Baldigo, Smith, Mckeown, & Faulring, 2015;Handcock et al, 2012). While the TIR literature from platforms such as satellites, aircraft, and handheld cameras is extensive (e.g., Handcock et al, 2012;Wawrzyniak, Piégay, Allemand, Vaudor, & Grandjean, 2013), it is only relatively recently that payloads of similar quality have been developed for integration with sUAS.…”