By: Randy Scholfield, communications director for TU's southwest region. Like many rivers across the West, the Dolores River in southwestern Colorado is on the front lines of climate change impacts. As the climate warms, the river will face lower flows, higher temperatures, and increasing stresses on fish and aquatic life.
How can we more effectively address these changes on a watershed scale? That’s the question driving a recent study by Trout Unlimited and other groups of the Dolores River basin.
“We know there will be change. The question the study addresses is what kind of change can we expect, the approximate timing and what are the impacts,” Duncan Rose of the Dolores River Anglers chapter of Trout Unlimited told the Durango Herald in a recent article.
To find those answers, the TU study—conducted in partnership with Mountain Studies Institute of Silverton—looked at climate models and trends between 1949 and 2012 that showed wetter periods of higher temperatures followed by longer periods of intense drought.
In projecting those trends into the future, some sobering results emerged: based on worst-case drought scenarios, the 46 trout streams in the Dolores Basin could lose some 44 percent of their flows in the next 50 to 70 years. Some streams, especially at lower elevations, might be lost causes to fish habitat, becoming intermittent or vanishing entirely.
But the study found that other middle- and higher-elevation streams could be made more “resilient” against the worst impacts of climate change through adaptive strategies such as habitat restoration, including improving in-stream structure such as boulders and pools to create cooler refuge areas for trout, and restoring streamside vegetation to provide more shade.
As important, the study field-tested an analytical model to determine which stream miles would best lend themselves to these efforts and provide the most “bang for the buck” for conservation outcomes.
“This is a framework that can be used across the West,” says Garrett Hanks, TU's Southwest Colorado field coordinator. “The issues in the Dolores are similar to many of our coldwater fisheries, and if we're going to be active in managing our coldwater watersheds into the future, this framework can inform many levels of TU’s strategy, such as how to identify and prioritize our protect, reconnect and restoration work.”
TU’s stream resilience work gives hope that many of our best trout waters can survive the worst impacts of climate change. The Dolores study could give TU another science-based tool for deciding where and how to dial in this adaptation work in watersheds across the West.
