Six Years of Stream Temperature Data

PRWC just completed its sixth season of thermal monitoring in the Pomperaug River Watershed!

PRWC’s stream temperature monitoring program is part of CT DEEP’s Volunteer Stream Temperature Monitoring Network. Stream temperature is an important component of aquatic life habitats as it affects the health and well-being of stream fish. PRWC’s objective is to generate data that CT DEEP can use to develop its water quality standards, assess fish habitats, and identify potential habitat restoration sites.

There are several components of PRWC’s stream monitoring program, including important steps to ensure the program generates high quality data. PRWC staff and volunteers first conduct quality assurance/quality control in accordance with CT DEEP protocol to certify that the temperature data loggers are fit for field deployment. Once the data loggers have passed quality control, they are programmed to record stream temperature every hour from June through August, which coincides with the summer low flow period as well as the critical rearing and growth season. The loggers are installed in six to thirteen monitoring sites, depending on funding availability, throughout the Pomperaug River Watershed in the spring and retrieved the following fall for data download. Volunteers perform field inspections monthly during the monitoring season to check for equipment tampering, confirm that the data loggers are still submerged in water, and record quality control temperature readings.

Using the methodology developed in Beauchene (2014), PRWC staff determine the thermal regime classification for each site using three stream temperature metrics: the June – August mean, the July mean, and the maximum daily mean. Based on a review of the six-year data set, Bullet Hill Brook at Ewald Park has the potential to be a cold water refuge for brook trout, an important source of sport fishing in the state. As climate change and its link to higher summer air temperatures continues to be a growing concern for brook trout, the identification of cold water refuges is imperative to the survival of this cold water species in our watershed.

PRWC prides itself in being a science-based organization. Its thermal monitoring program continues PRWC’s mission to utilize the latest science to support data-driven decision-making in protecting the health and vibrancy of the Pomperaug River Watershed and with your support, we can expand our network of monitoring sites.

To view the stream temperature data of each site, visit PRWC’s thermal monitoring interactive map, click on the site of interest and then the monitoring site photo or the More Info hyperlink under Site Data.