Water Temperature Data

In 1999 The Friends of the Boyne River recorded baseline temperatures for the Boyne River.  Boyne USA provided continuously recording thermometers for the project.  The thermometers were placed at 7 sites to specifically determine the warming effects of the various impoundments throughout the river system.  Temperature readings were recorded hourly from July 16 to September 24.
  

The map below shows the location of the recording sites

(Click on the numbered locations on the map to review the data)
 

Some Observations
 

The South Branch above the Boyne Falls mill pond and the entire North Branch are both prime cold water trout streams with the highest summer temperatures well below the 70 degree mark.

The large surface area of the Boyne Falls mill pond warms the South Branch by about 10 degrees.

The cold waters of the North Branch mix with the waters of the South Branch about 1 mile below the Boyne Falls mill pond.  That, and the likely addition of spring water, cools the Main Branch to summer temperatures that are well below the 70 degree mark.

The Main Branch below the Boyne USA power plant reservoir averages about 75 degrees during the heat of summer with a few days hitting 80 degrees for brief periods.  Trout still seem to thrive in this area above and below Dam Road as demonstrated by the MDEQ fish survey.  This is probably due to excellent habitat and the fact that nighttime temperatures are significantly lower than the brief daytime highs.

The Main Branch below the Boyne City mill pond has a significant number of daytime temperatures above 70 degrees with a greater incidence of highs hitting 80 degrees.  Trout in this area tend to migrate to cooler water during the heat of summer, however, during spring and fall this is a major migration route for salmon, steelhead and brown trout.  In the spring juvenile salmon spend some time  feeding here as they make their way to the cold deep water of Lake Michigan.