THE DIRTT PLAN and eDNA
Cooler water. Clearer flows. Better science for the Henry's Fork.
Water temperatures, turbidity, and changing hatches are among the most important questions facing the Henry’s Fork.
Through the DIRTT Plan — Developing Infrastructure to Reduce Temperature and Turbidity — HFF is evaluating large-scale engineering and grounded, nature-based solutions to improve water quality and build resilience for the river, trout, aquatic insects, and the people who care about this place.
Potential solutions include deep-water oxygenation in Island Park Reservoir, sediment reduction, tributary restoration, and variable-elevation withdrawal at Island Park Dam.
Nothing like this has been done on the Henry’s Fork before.
A New Way to Read the River
As part of DIRTT, HFF is also using environmental DNA, or eDNA, to better understand what is happening beneath the surface.
HFF and the Salmonfly Project are testing a first-of-its-kind approach on the Henry’s Fork: using eDNA alongside traditional insect monitoring and emergence traps to better understand PMD hatch timing.
PMD hatches are part of the Henry’s Fork’s identity. They feed trout, shape the fishing day, and connect anglers to the rhythm of the river. But in recent years, that rhythm has become harder to read.
Are insects emerging earlier? At night? In different places? More sporadically? Are warming temperatures changing the timing and intensity of hatches?
By collecting water samples, scientists can detect tiny traces of genetic material left behind by insects, fish, and other organisms. Over time, this work could help HFF better understand changing hatches and evaluate whether future DIRTT actions are improving conditions for fish, insects, and the river.
This work is conducted in partnership with the Salmonfly Project, with important access and support from Harriman State Park, the Forest Service, and Flat Rock Club.
Your gift helps HFF turn better science into better conservation decisions.
"The ability for a group of people to do remarkable things hinges on how well those people can pull together."