Earlier this year a group of BVFF volunteers (Troy Pearse, Brian Martin, Greg Hitchcock, Scott Lenz and Randy James) met on the Owyhee river to hash out the details of the augmentation. 100 cubic yards is a lot of gravel, and the big question we had to answer was how far it would go, and where in the river to put it. To give you an idea, at 6 inches deep, 100 cubic yards of gravel will cover about 5,400 square feet — roughly a 90-by-60-foot patch, about the size of two tennis courts side-by-side. That amount of gravel will support as many as 500 brown trout redds!
Brian hopped in the water and started checking depths and flows--looking for water that was between 9 inches and 2 ½ feet deep and moving at a slow walking speed of 1 - 2 mph. Once he had an area probed, he and Greg measured the area while Scott Lenz ran the calculations of how many yards of gravel would fit in each zone. That morning we were able to identify 4 zones in the run along the road below Sand Hollow Cr and an additional zone in the tailout below the Concrete Bridge, 1 mile downstream.
We had planned to do the gravel augmentation in late winter of 2024/2025 -- after any possible ice out and before spring runoff. But it was a good snow year and the irrigation district started releasing water early so we decided to delay until fall of 2025, after irrigation flows dropped for the season. That way we could accurately target gravel placement in the right water types, and make sure it was safe for volunteers to be in the river.
Jeanne Garcia sent out a news release for the project and Steve Dent from Channel 6 News showed up to cover the story. He flew a drone over the project, which was a great view of the gravel slinger in operation. One question it raised from people watching was the amount of dust in the air. Rest assured that we used clean/washed gravel--the slinger conveyor belt just shook off any last dust before throwing it. Here is a link to that news story.
We started staging the gravel in mid-October, a few days before the augmentation. Randy James met Troy at the side-road up to the staging area and we filled in some ruts to make it easier to get the big trucks up there. It took 7 dump truck loads from nearby gravel pits.
The night before the augmentation, Brian and Troy placed some milk-jug buoys at each gravel-zone to give the slinger operator a target to shoot at. The next morning, ODFW fish biologist Dave Banks reviewed the proposed augmentation zones and made some adjustments, including recommending placing more gravel in the uppermost zone so that when the gravel starts shifting downstream it would repopulate the areas below #SmartMoveDave!
This was the first time we have used a gravel slinger, and we were all excited to see it in action. It certainly beats hauling the gravel to the river in wheelbarrows! The next morning, Matthew and Randy, the slinger and front end loader operators from CMCI showed up and we hashed out a plan for loading and slinging the gravel.

Scott Lenz had worked out a a traffic control plan and put together a team of BVFF volunteers to manage traffic around the slinger and loader operation and to keep the road clear of gravel. The 2-way radios that George Butts brought made that much easier, given there is no cell service in the area. Thanks to Dave Asker, John Shrum, Joe DeSousa, Randy James, Greg Evans, George Butts, Mike Stahl, Steve Conrad, Tim Opp and Keith Gerard.

It was a beautiful, fall day, and soon the gravel was in the air! The gravel slinger was like a gatling gun, rapid-firing gravel rounds into the river. Here is a link to a video of the slinger in action! GravelSlingerVideo.mp4 . The operator, Matthew, laid down a test stripe of gravel and then paused while Jeff Jones tested gravel depths to see how close we were to the desired 6 inches. During the pause, Klaus Kissman, Mike Wiedenfeld and I collected our first water samples 100 feet upstream and downstream of the activity and tested them for turbidity, a requirement of our DEQ 401 Water Quality permit.
Jeff relayed the gravel depths to Matthew and he adjusted his timing to get a bit thicker layer and resumed throwing gravel. The slinger worked better than we could have imagined, throwing a truck-load of gravel into the river every 20 minutes and the reload cycles gave time for any stirred-up sediment to settle, keeping water quality well within the tolerances required by our DEQ 401 permit.
BVFF volunteers managed traffic around the slinger and loader operation and kept the road cleared of gravel--sweeping and shoveling any spilled gravel into wheelbarrows so we could reload it into the slinger to make sure we got as much gravel into the river as possible.
The morning flew by and the next thing we knew George Butts and Phil Toscos from Sunroc (now Suncor) showed up with lunch. Sunroc/Suncor has been very supportive of our gravel augmentations, donating gravel for our 2 Boise River gravel augmentations and giving us a significant discount on the gravel for this project. What awesome partners! Thanks for lunch, Phil!
As we neared the top of the Sand Hollow run we paused operation, as we wanted to make sure to reserve enough gravel to do the tail-out below the Concrete Bridge as tail-outs are prime locations for brown trout to spawn. Once we got down to the last truck-load of gravel we headed downstream and filled the tail-out with gravel.

To ensure we didn't scoop up dirt and threw only clean gravel, the loader operator had left a layer of gravel at the staging area. BVFF volunteers looked at that and saw more potential brown trout redds and they sprung into action-- working with Randy to carefully scoop extra gravel and then shoveling what they could into the HUGE loader bucket. Their hard work resulted in being able to come back upstream and lay down a "bonus zone" right below the riffle. Nice Job Guys!
This has been a long and complex project and couldn't have happened without the partnership with ODFW, especially Malheur District Fish Biologists Dave Banks and Kirk Handley. Project funding came from grants from Fly Fishers International, ODFW’s Salmon Trout Enhancement Program, the Snake River Waterkeeper, and the generous donations by Sunroc/Suncor and CMCI. BVFF funding came through an Idaho Gives campaign led by Brian Martin and Deborah DeSousa; a "Greenbacks For Redds" club fund raiser; raffling a beautiful custom knife made by Mike Okamura; and funds raised at our yearly Fly Fishing Expo.
I want to give a special shout-out to all of the volunteers who make BVFF's yearly Fly Fishing Expo happen, which is the main fund-raising engine for BVFF's Fly Fishing Education, Conservation, and Access projects. The expo committee has been hard at work getting the 2026 Expo ready and I encourage you to volunteer [ADD LINK]
Brown trout are fall spawners and generally spawn from October through mid-December on the Owyhee. ODFW has been doing fall spawning surveys for many years and will track redd counts in the new gravel. We expect some brown trout will find the new gravel and make redds there this fall, and that use will increase over the next 5 years. ODFW also does summer electrofishing surveys but it will take several years before the new brown trout from this gravel will show up as adults.
Brown trout redds will be harder to identify the first year, as the clean gravel makes it difficult to see where the trout have been digging. If you are out at the Owyhee in the next couple of months, we encourage you to stop and check out the new gravel and report back if you spot any trout on it. Viewing from the elevated roadway or bridge is the best approach, and polarized sunglasses are a must! Post a photo to BVFF's Facebook page or email us at conservation@bvff.com along with any comments about where you saw the fish. We will compile all of the reports and share them with ODFW to help guide their December redd surveys. And please remember to avoid wading through gravel spawning areas this time of year, and avoid harassing the spawning fish. We want all the baby trout we can get!
OUR SPECIAL THANKS TO THOSE WHO
HELPED FUND THIS GRAVEL AUGMENTATION

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FAQ
1. Why did you choose this location?
ODFW's annual fall spawning surveys show that the lower reaches of the Owyhee River have limited spawning activity. By increasing spawning habitat the brown trout population will (hopefully) improve.
We worked with ODFW to select the site. ODFW has seen no spawning activity in this section of river, even though it has the right depth and flow velocity. By adding smaller gravels, it should be perfect spawning habitat. If you build it, they will come.
Proximity to the road allows us to use a gravel slinger to get the large amount gravel into the river with minimal water impact.
2. Will the gravel shift downstream?
Based on observations of our Boise river gravel augmentation, we expect this gravel will stay in place until river flows exceed 4,000cfs. The club is working with Biomark on tracking gravel movement using PIT tags. You can read more about that in this Conservation Blog Article.
3. How do you know if the project is a success?
ODFW does annual fall spawning (redd) counts and will be monitoring for changes. They also will monitor the adult trout population using electrofishing.
4. How long will it take for brown trout to utilize the new gravel?
We expect some brown trout will use the gravel to spawn this fall, and that use will increase over the next 5 years. Rainbow trout spawn in late spring and will also be able to use the gravel for spawning.
5. What size is the gravel being added?
Gravel is clean/washed round river gravel ranging from 1/2" to 2" in diameter. We added approximately 6 inches of gravel.
6. What permission and permits were required?
We submitted a Joint Stream Alteration permit to the Oregon Army Corps of Engineers, Department of State Lands, and the Department of Water Quality. To submit the permits we needed permission from the landowner (BLM) and approval from Malheur County Planning and Zoning. DEQ required that we monitor water turbidity every 2 hours and adjust the pace of the project if there was too much sediment. For more info on the process, see this Conservation Blog Article.