Know Your Watershed: Streamflows & Wildlife

Prehistoric birds are nesting among us. Thanks to the flowing waters of the Uncompahgre River that feeds into the Gunnison River, the great blue heron lives year-round in Ouray County. How would this species be affected if stream flows changed or water resources were depleted?

A great blue heron on the Uncompahgre River at the Pa-Co-Chu-Puk area of Ridgway State Park

Photo by Judi Chamberlin

The Uncompahgre Watershed is teeming with wildlife that is connected in a variable, wild chain of life. The water in the river feeds everything from the grasses and fauna inside and around it, to the ungulates like elk and deer. Aquatic insects are an important link in the food chain, providing stocked Kokanee salmon and wild trout with feeding resources for carrying out important functions, like spawning and traveling upstream. Thus, the great blue heron has a food source as well–eating fish and more.

As the streamflows change throughout the seasons according to precipitation and snowmelt, so do the behaviors and distributions of organisms in different parts of the watershed. For example, aquatic insects are adapted to the rhythm of high snowmelt flows in spring that gradually taper down to the low base flows of fall and winter. If the timing or magnitude of this rhythm changes, then the insects cannot complete their life cycles and the food web takes a big hit.

So how might streamflow affect the nesting areas of the great blue heron? Many years ago, when the area was filled with glaciers, you probably wouldn’t have found many heron nesting groups. When the Uncompahgre River and surrounding wetlands developed after the glacial period, they became attractive to herons that like to build nests in high trees surrounded by water. Ridgway Reservoir, Dallas Creek, and Cow Creek also became popular heron habitats. Without efforts to preserve our streamflows during every season, we may not have the gift of observing these prehistoric giants year-round.

Test Your Knowledge: Measure what you know about the effect of flows on ecosystems by taking this quiz. If you wish to be put in a drawing to win a RiverFest shirt, please provide your email address with your answers.

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Don’t forget to make your peak flow prediction for 2023 and you may win great prizes in the Uncompahgre River Classic!