Last week, BVFF shared details on our gravel tracking project at the the Idaho Water Quality Workshop. BVFF and Trout Unlimited also shared details about Boise River gravel augmentations done over the last 20 years, including observations of gravel movement.
BVFF did its first gravel augmentation 5 years ago, and we have continued to work in the side channel to improve trout habitat, which has been a good learning experience. Going into the first gravel augmentation we thought that gravel was the lone missing ingredient for trout spawning. What we have observed is that 1) Side channel connectivity is just as important as gravel--as without adequate water in the side channel, brown trout do not spawn; and 2) Woody cover is a critical element that increases fry survival.
Here are a couple of Conservation Blog entries about our past gravel augmentations.
TRACKING GRAVEL MIGRATION
We put together a poster for the March 2026 Idaho Water Quality Workshop that highlights some of our observations of gravel movement in our side channel (shown below). It was pretty clear that our gravel moved from its original locations, and that the magnitude of movement was related to the volume of spring flows. We can see some new gravel accumulations at several different spots in the side channel that we think may be from our augmentations, but it is impossible to know.
Last week we received our Stream Alteration Permit from IDWR and approval from USACE (permit submitted) and Ada County.
Tuesday (March 11, 2026), we placed 0.9 cubic yards of gravel at the top of the side channel, including 54 pieces of PIT-tagged gravel. The plan is to use a PIT Tag Detector and sweep the side channel each Fall for 5 years, to see where the tagged gravel ends up. Observations will help guide future gravel augmentations.
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It is impressive that a volunteer organization has been able to put together this gravel tracking project. Special thanks goes to BVFF club member Jeff Jones for his efforts to lead the --it would not have happened without his expertise and leadership. We would also like to thank Nick Porter and Biomark for their partnership on designing and participating in the study.
Over the next 5 years, the "Easter Egg Hunts" down the side channel, looking for tagged gravel will be very interesting. For the first year
