Roaring Fork Conservancy’s Hot Spots for Trout program has engaged 50 volunteers to collect over 440 temperature readings at 21 locations throughout the Roaring Fork Watershed in only 6 weeks. The Hot Spots for Trout program was launched on June 28, 2012 in response to the severe 2012 drought, which continues to diminish flows and increase temperatures in local rivers. Collecting temperature data has assisted local wildlife managers in decisions to abate fishing in areas where fish and other aquatic life were already stressed.
Volunteer Greg Bovee of Carbondale explained that the “2012 has been an especially challenging year for the Roaring Fork watershed. Hopefully, the work of the volunteer hotspotters will shed some light on the affects of a very low snow-pack, drought conditions and excessive water diversions on our natural rivers and their ecosystems. Temperature data is but one element of effective river monitoring.”
During the week of August 5, 2012, four monitoring locations exceeded the state temperature standard of 68 degress Fahrenheit. These include the Crystal River near CRMS in Carbondale, the Roaring Fork River near the Carbondale boat ramp, Brush Creek near the Snowmass Village Rodeo Round About, and the Roaring Fork River in Aspen at the Hopkins Street footbridge. Afternoon rains have helped to keep rivers cool, however the low flows are still permitting river temperatures to rise.
The state standard for temperature in the Roaring Fork Valley is a maximum of 68 degrees Fahrenheit. Colorado Division of Parks and Wildlife is authorized to close sections of the river if daily maximum temperature exceeds 74 degrees Fahrenheit, or if average daily temperature exceeds 72 degrees Fahrenheit.
How hot or cold the water is determines what can survive in it. Aquatic species have evolved to live at certain temperatures ranges. For example, Brown Trout adults thrive at temperatures from 54-66 degrees Fahrenheit. In the upper and lower limits of that range, an organism becomes stressed, meaning it could be at a competitive disadvantage for food and more susceptible to disease or in extreme cases death. In addition, temperature influences both water biology and chemistry. For example, temperature affects how much oxygen is in the water. Elevated temperatures lead to decreased oxygen levels, which in turn negatively impact aquatic plants and fish. Increasing temperatures also promote growth of bacteria and algae which can increase pH and use even more of an already depleted oxygen supply.
Thanks to the Glenwood Springs Post Independent for the heads up.