Water Quality Monitoring Begins at Trout Brook in Preparation of Dam Removal

On Wednesday, July 2, Lauren Weston and Viva Goetze of the Franklin County Natural Resources Conservation District (FCNRCD) met with Becky Tharp of Just Water Consulting LLC at the Trout Brook Reservoir Dam in Berkshire, VT to collect water quality data and set up continuous monitoring equipment before the dam is removed. 

Viva Goetze paddles across the Trout Brook to collect water quality measurements. 

The Trout Brook Reservoir Dam was built in 1924 on Trout Brook, a tributary of the Missisquoi River, to provide drinking water for the Village of Enosburg Falls. It was used until 1946 and has not been maintained since. 

The Franklin Country NRCD plans to remove the dam in July and August 2025. Removing the dam will improve water quality and aquatic habitat by restoring natural river processes, lowering temperature, increasing dissolved oxygen content, and eliminating the sediment build up behind the dam. Dams interrupt the natural connectivity of streams and rivers – by removing the dam, brook trout and other aquatic species can access habitat which has been blocked.  

On this trip, water quality measurements were taken, and continuous monitoring equipment was installed to collect data on stream temperature and dissolved oxygen levels upstream of the impoundment, in the impoundment, and downstream of the dam. This will provide a baseline for assessing water quality before and after the dam is removed. A pressure transducer was also installed, which will record continuous on-site barometric pressure, and will be used later to convert dissolved oxygen concentration data to percent saturation.  

Becky Tharp instructs on how the water quality data loggers will be set up. 

A sonar depth finder was attached to the back of the kayak which was paddled around the impoundment to find the deepest area of the water column, which became our sampling point and location to install a dissolved oxygen and temperature logger for several weeks. A stratification test of the water column was completed, where a handheld multi-parameter probe was lowered into the water at marked intervals to measure temperature and dissolved oxygen. The deeper readings indicated lower dissolved oxygen – indicating “reducing” conditions near the sediment water interface, probably due to organic sediment deposited behind the dam. Finally, an Onset Hobo Data Logger was secured at 50% depth, which will continuously collect data on temperature and dissolved oxygen content of the water, was secured in PVC housing, attached to a buoy, and anchored to a cinder block dropped to the bottom of the impoundment.  

The Trout Brook downstream of the dam is much shallower, so there is no need for a stratification test as it is all flowing water. A reading was taken of the temperature and dissolved oxygen content, and an Onset Hobo Data Logger was installed to continuously monitor dissolved oxygen and temperature in the water downstream of the dam. A third logger will also be installed upstream of the impoundment to capture temperature and dissolved oxygen metrics above the influence of the impoundment as a reference point. 

Viva Goetze takes water quality measurements below the Trout Brook Dam. 

For the next few weeks, these loggers will continue to collect data. The loggers will be removed before the dam removal occurs. In the summer of 2026, the loggers will be reinstalled in similar locations to track changes as a result of the dam removal. Once the dam is removed, we expect to see the temperature decrease and dissolved oxygen levels increase as the Trout Brook returns to its natural stream state.