Identifying Thermal Refuges in the Schoharie Watershed Active

Problem

Water temperature is a critical component of trout habitat. Stream temperatures not only affect the distribution, behavior, and survival of trout (and other species), but also compel these species to move toward small areas of preferred temperatures, known as refuges, to maximize growth, survival, and fitness. The Schoharie watershed in the Catskill Mountains, including East Kill, West Kill, and Batavia Kill tributaries as well as the main-stem Schoharie Creek, supports small or transient populations of wild brook trout as well as naturalized and hatchery brown trout. Water temperatures in parts of these rivers typically exceed lethal thresholds for these species for several weeks each summer. Managing agencies within the Schoharie watershed are often confronted with decisions that impact the thermal profile of the stream, such as permitting new discharges or other watershed alterations. Assessing the effects that these alterations may have on local trout populations, and ensuring that the alterations do not inadvertently destroy potential thermal refuge, requires data on the size, location, and number of thermal refuges within the watershed.

Objectives

Primary objectives of the study are to:

• assess the thermal profile of the main-stem Schoharie Creek and one of its tributaries, West Kill, using airborne thermal remote sensing,

• characterize contemporary thermal conditions, and

• determine the spatial extent of cool-thermal refuges and harmful (warm) surface waters.

Approach

The U.S. Geological Survey (USGS), in collaboration with the Rochester Institute of Technology, mapped surface water temperatures along the West Kill and main-stem of the Schoharie River using airborne thermal infrared (TIR) photography. The TIR data will be supplemented with 6-8 in-stream temperature loggers along the study reach, which will record water temperatures in 15-minute increments to provide daily and seasonal in-stream temperature fluctuations, and can be used to calibrate TIR data. 

Publications

Scott D. George, Barry P. Baldigo, Martyn J. Smith, Donald M. McKeown & Jason W. Faulring (2015): Variations in water temperature and implications for trout populations in the Upper Schoharie Creek and West Kill, New York, USA, Journal of Freshwater Ecology, DOI: 10.1080/02705060.2015.1033769

Project
Location by County

Greene County, NY, Delaware County, NY