The Importance of Coldwater Streams in the Mount Grace Region
Mount Grace’s region stretches over 23 towns and encompasses parts of the Deerfield, Connecticut, Millers, Chicopee, and Nashua River watersheds. Wetlands across our region are varied and complex, providing habitat to hundreds of thousands of organisms. Among these, cold-water streams stand out as a unique and essential habitat, found primarily in the higher-elevation areas of our region.
These streams can be small or medium-sized and are fed by groundwater springs, snowmelt, and runoff. Their name comes from the fact that they stay below 65 degrees Fahrenheit during the summer. This means they not only provide refreshing summer swimming areas, but they also offer important habitat for heat-intolerant species, especially as temperatures rise in other water bodies during summertime months.
What does a healthy cold-water stream look like?
Cold-water streams support a variety of habitats. As they meander through the landscape—along shaded forest floors or through open-sky wetlands—they form deep pools that flow into shallow zones filled with cobble and gravel, which help filter the water and maintain a healthy aquatic ecosystem. Crayfish, dragonfly nymphs, juvenile fish, cased caddisflies, and giant stoneflies are just a few of the invertebrates that thrive in these gravelly, leaf-strewn pools. Eastern brook trout, fallfish minnows, and slimy sculpin rely on cold-water streams and eat aquatic invertebrates. Downed trees that have fallen into the water provide shade—helping keep temperatures cool—while also creating structure where turtles and fish can shelter from predators.
Coldwater streams are also intimately linked to the forests around them by creating riparian zones, or the in-between area of land and water. You can find species such as turtles, otters, wood frogs, spring salamanders, and moose feeding in and calling these areas home. Periodic flooding is a crucial aspect of riparian habitat, as it maintains nutrient cycling, soil fertility, and habitat diversity. It also helps mitigate any flooding downstream, where there may be metropolitan areas at risk of floods damaging infrastructure.
Degradation of cold-water streams
All of integral aspects of cold-water stream ecosystems mentioned above can be lost or degraded due to urbanization, stormwater runoff, increased storm frequency and intensity associated with climate change and disruptions to stream flow and connectivity associated with dams and channelization. Damming in particular can create shallow, stagnant pools of water that are more susceptible to solar warming, disrupting fish movement and generating additional downstream impacts. Warmer waters no longer provide the cool refuge that many species need to survive, depletes dissolved oxygen, and can cause algal blooms.
Working to keep cold-water streams healthy
Keeping these streams cold and healthy is an important responsibility that Mount Grace takes seriously. A fantastic example of a cold-water stream (and a great place to walk or fish!) is the Gifford Family Memorial Forest in Orange where the West Branch of the Tully River flows. This year, TerraCorps member Emily Volmar is taking a close look at this cold-water stream and the land around it to assess aquatic health. This work is done by collecting water quality and temperature measurements, assessing wildlife presence, and consulting experts. Her work will help inform land stewardship decisions, as well as augment our knowledge of the species that call Gifford home.
Upcoming events highlighting cold-water strean habitat
If you’re interested in learning more or helping with this work, we have two upcoming events at Gifford. On April 13th, there is a volunteer workday to remove invasives in the riparian zone, and on the 24th, there is a vernal pool assessment walk. Learn more by visiting the Get Involved section of the Mount Grace website. And to learn more about healthy streams and rivers, join us at 4 Star Brewery in Northfield on April 7th as we celebrate Give Back to the Land Day.