BVFF’s Redd Count and Mapping project wrapped up at the end of December. The club did 7 day-floats from Willow Lane (in mid-Garden City) down to Star to count and mark redds. Thanks to Johnny Rogers, George Butts, Jeff Jones and Klaus Kissman for their help. We delivered a few updates to the Flood District’s Redd-Map as well as discussed the possibility of repurposing a few downed trees into side channels for trout habitat.  We are grateful to have such great partners who care about protecting and improving trout habitat in the Boise River.

Figure-1 shows a high level map of the larger redd-zones we are tracking on the Boise River.  For more details about BVFF’s “Redd Protection Program” with the Flood District, see this conservation blog article. 

One thing I was looking for this year was how much new gravel the high spring flows stirred up. From what we observed, new gravel recruited from last spring’s high water was primarily deposited at “high water locations”, which are out of the water during the low flows of winter and unavailable for brown trout to spawn in November and December, but, this gravel will be available for rainbow trout to spawn when the flows come back up in the spring.  We did see some changes to the river from high water which impacted brown trout spawning, including:

• Behind Lake Harbor a new gravel bar popped up in the middle of the river and the brown trout found it!
  
  
• A large spawning area behind Expo Idaho experienced shifts in a gravel-flat which impacted water depth and velocity—reducing the number of redds there this year;
  
  
• A 200-foot-long gravel island above Glenwood Bridge that used to have brown trout redds washed away and didn’t have any redds this year, but…there was new gravel accumulation nearby that did;
  
  
• Below Glenwood Bridge a run-riffle-run that had redds in the tail-out between them is now a single long run with no redds.
  
  
• The entry to New Dry Creek diversion was dewatered for a repair, which made a redd-zone unavailable this year. But the good news is once the project is complete there will be some “leftover gravel” there that brown trout will be able to use next year.
  
  
• In the side channel where BVFF did our gravel augmentation last year, most of our gravel was moved to the lower half of the side channel and left at higher water locations that are out of the water now but will be available to rainbow trout in the spring. The number of brown trout redds in the side channel was down this year as gravel in one redd-zone was washed away.

Although there were changes to the river from high-water, the majority of the larger redd zones were active this year with an increase in the number of smaller spawning sites that just had 1 or 2 redds (which are not on this map). Overall we saw slightly fewer redds this year but we know that there was some late spawning this year and and it is possible that we missed some redds that were in new locations. And, as described above, there were some changes to several of the larger redd-zones in the main channel this year that resulted in fewer redds at those sites. I also feel like we are getting more accurate at our redd counts and avoiding some areas of current-scour that we may have mistakenly counted as a redd in previous years.    

Below Glenwood bridge the Boise river splits into 2 channels that flow around Eagle Island, as shown in the photo below. The north channel has many more small twists and turns than the south channel, which causes the river to drop more gravel and improves trout spawning habitat there, resulting in more spawning activity (which you can see by how many redd-zones the north channel has on the map). The amount of water entering the north channel varies from year-to-year depending on cobble accumulations at the head of Eagle Island. Table-2 shows the flows in November of 2022 vs 2023 and you can see how the north channel got more water this year, which made more spawning habitat available to the brown trout and is likely the reason we saw more spawning activity in the north channel this year. Brown trout are known to migrate to find spawning habitat and based on the redd counts the last 2 years it looks like some of them may have decided to spawn in the north channel this year because of the favorable conditions.

Many of the brown trout redds on the Boise River are close to the bank where the river has recruited gravel, like the redds shown in the photo below. Because of this, water flows are a big factor in what bankside spawning habitat is available to brown trout in the winter.  Low winter flows dewater some side channels and as water levels go down the river recedes from the banks where much of the spawning gravels are located.

In the 1980s and 90s, Idaho Fish and Game worked to establish minimum winter flows in the Boise River which significantly improved the wild trout populations because it brought water levels up and improved access to trout spawning and rearing habitat. When we have good reservoir carryover conditions (like this winter) the Boise river typically runs around 270cfs - 280cfs at the Glenwood Bridge gauge during the winter but in drought years that drops to around 210cfs or even lower, which dewaters the banks more. IDFG has some water rights in Lucky Peak and has been investigating increasing the minimum winter flows to 300cfs to improve trout spawning and over-wintering habitat which would be a great improvement for the wild trout on the Boise river and I would love to see it happen—even if it only happened on years when we have a good reservoir carryover.

Last week I got the opportunity to help Tim D’Amico, Idaho Fish and Game fisheries biologist, with a trout fry (electro-fishing) survey on the Boise River side channel where BVFF has been working on trout habitat improvements (see this Conservation Blog article for details). We surveyed the same 3 spots as last year--one at the top, one mid-channel and one in the lower section. The total fry numbers were down compared to last year, but that was mainly because the tree across the channel at the lower site where we had found so many trout fry last year had pushed downstream and we only found a couple of trout in that zone. The fisheries biologist said that was one of the limitations of their fry survey--that changes to the river can impact the productivity of a sample site. (See this Conservation Blog article for more information about last year's fry survey.)

One of the habitat improvements we did on the side channel last February was to place a tree root-wad in the upper section, with the assistance of the flood district’s excavator. This year’s high runoff flows scoured out a good hole there and we found both fry and 1–2-year-old brown and rainbow trout holding around the root-wad. Seeing the age 1-2 trout is extremely exciting because it is a good indicator that our side channel habitat improvements are helping trout over-winter survival, which IDFG tells us is the bottleneck for improving recruitment from fry into adulthood.

I passed along photos and kudos to the flood district and will be working with the new flood district manager, Mark Zirschky, to identify other downed trees that can be possibly be repurposed/placed in other locations to improve trout habitat during their winter operations. This opportunity to improve woody cover in the Boise River is extremely important and I am grateful for their forward thinking and willingness to help protect and improve trout habitat in the Boise River. (See this Conservation Blog article for more information on this awesome project!)

I had been concerned that the high flows from the early release of water in April would be a problem because it occurred so close to brown trout fry-out (when the fry leave their redd/nest), but we found lots of brown trout fry indicating that the side channel and woody cover was a good place of refuge from the high flows. So far, I haven't seen any brown trout redds in our side channel this Fall, but I have seen some in the main river. During the survey we found one large (20") brown trout at the end of the side channel, who appears to be staged to spawn. Last year most of the spawning in the side channel happened in December, so I am hopeful we will see some redds soon.

BVFF will start floating the Boise river this week to document brown trout spawning and update the redd-zone map for the flood district so they can avoid the redds during their winter maintenance. The high spring flows recruited new gravel from the river-banks and it will be very interesting to see where we find brown trout spawning this year.

In December I will be participating in a trout fry survey at the Diane Moore Nature Center side channel (the same place we did our snorkel survey this summer). Flows are down significantly in that side channel, but there are some deep pools and lots of woody cover. The total number of trout fry we saw in that side channel last summer was amazing, and there is lots of good woody cover for them, so I expect we will see an increase in the adult population of trout there over the next few years. For more information about this successful side channel restoration, see this Conservation Blog article.

REDD NOVEMBER

November is peak spawning time for Brown Trout on the Owyhee and Boise River. Please watch for redds as you wade and avoid walking through them. Browns like to build their redds in 1-3 feet of slower moving water and love tail-outs and next to gravel banks. Here is a look at brown trout redds on the Boise River and a short YouTube video on how to spot redds when you are wading.

Side channel habitat is one of the most important factors for a healthy wild trout population. They provide good spawning habitat for adult trout and more importantly good rearing habitat for young trout—the reduced flows in the side channel are much easier for the young trout to handle than the main river and the side channel’s extra bankside woody-cover gives young trout a place to hide from birds and other predators. Side channels that flow year-round are the most important because they provide shelter during the winter which is critical for young trout to survive into adulthood.

The Boise River through town is an urban tailwater river which over time has reduced its side channel habitat and has become a limiting factor for wild trout reproduction. Idaho Fish and Game does trout fry surveys in the Fall that show the Boise River has a healthy population of wild rainbow and brown trout. And their surveys show that trout fry populations are 7-10 times higher in the side channels than the main river. Unfortunately, there are very few side channels on the Boise River that flow in the winter.

A SUCCESSFUL SIDE CHANNEL RESTORATION

Two years ago the Intermountain Bird Observatory led a Boise River side channel restoration project at the Diane Moore Nature Center, which is located a couple of miles downstream of Lucky Peak Dam—above Barber Dam. The side channel was engineered to provide good habitat for fish and wildlife including plenty of woody cover for small fish to seek shelter.

BVFF got involved in the Diane Moore Nature Center side channel project in 2022 and helped design and install Trout Habitat signs along the side channel, followed by building an Angler Access at the site. BVFF has been thrilled to be involved in this project because it supports all three of our mission goals: Fly Fishing Conservation, Access, and Education.

The first spring the side channel had water (2022) there was limited trout spawning observed, likely because Boise River flows came up late. And in the second season (2023) we had high spring flows making it impossible to see if trout were spawning there. This summer while walking the side channel we saw small “minnow-sized” fish but were not able to identify them. So, we decided to stick our heads underwater to see what we would find! Our goal was to see how trout are using the new side channel and get an idea on numbers and distribution.

A snorkel survey is a standard way to count trout fry. We talked with Tracy Hillman, Senior Ecologist at BioAnalysts who specializes in trout habitat restoration, and he talked us through the process and gave us a great document on how to do a snorkel survey. August 29th, volunteers from Boise Valley Fly Fishers (Troy Pearse, Klaus Kissman and Dennis Moore) did a fry snorkel survey in the new side channel at the Diane Moore Nature Center. Even though it was summer, we wriggled into wetsuits to protect us from the extended cold-water exposure and debris in the water. We started at the bottom and had 2 people snorkel upstream side-by-side counting the fish they saw. This was our first snorkel survey and we didn’t know what to expect, but we were flabbergasted when we went underwater and started seeing rainbow trout fry everywhere! The side channel is about 0.4 miles long and we snorkeled sections from the bottom to the top—covering about 3/4 of the total length—counting over 2,000 trout fry which were evenly distributed throughout the side channel!

A large part of the success of this side channel is the extra effort made to add woody-cover: There are numerous downed trees and log-piles in the side channel which give the trout fry a good place to seek shelter. Observing the trout fry underwater was a great way to see this as many of the fry were tucked under pieces of wood in the water with some large pods of trout fry by logjams.

The vast majority of trout in this stretch of water are wild, as Idaho Fish and Game does not actively stock this section of river. We are excited about the potential of the side channel to increase the population of wild rainbow trout in this section of the Boise River, which is isolated between two dams: Barber Dam below and the New York Canal Diversion Dam above.

The side channel has restricted inflows in the winter but talking with Greg Kalteneker (who lead the side channel project), the side channel was designed to connect with groundwater and last winter the water station installed on the side channel showed it flowed at 1cfs - 3cfs. Hopefully that will be enough inflow to keep it from freezing. We plan to check it a few times this winter to see how it is flowing and if it is icing over.

IDFG Historical Fish Stocking Records

A SIDE CHANNEL OPPORTUNITY

As good as the trout population is on the Boise River, it is not reaching its full potential. One of the best things we can do for the Boise River wild trout population is increase the number of side channels that have year-round flow for trout spawning and rearing. BVFF is working with Idaho Fish and Game to restore winter flows to two side channels behind Expo Idaho that were cut-off from winter flows after Snowmageddon in 2017. Idaho Fish and Game will be on-site at these side channels this Fall when Boise Rivers flows drop. They will be documenting the side channel dewatering and evaluating possible trout-fry stranding, including possibly rescuing stranded trout fry and moving them to the main river. BVFF is volunteering to assist them. Stay tuned for more details and sign up if you are interested. The current estimate for flow-reductions on the Boise river is the morning of Monday October 15th, but that time could change.

UPDATE 10/5/2023: The Boise River dropped earlier than expected. IDFG sampled the side channels and identified several pools with stranded trout fry and thousands of minnows.  They electrofished a couple of pools and rescued several dozen trout fry. We will help them monitor the pools over the winter to see if they ice-over and IDFG may electrofish them in the spring to evaluate overwinter survival.   

I spent the day at the Diane Moore Nature Center and Barber Pool with Brian Martin and Dennis Moore, reviewing the side channel and evaluating trout spawning habitat in the Barber Pool. We even did a little fishing!

When we arrived at 9am there were PMD Spinners, trico spinners and some caddis on the water, and there were a couple of anglers out fishing below the NYC Diversion Dam. We did a little seining and found good numbers of mayfly nymphs, some green netspinning caddis and a cranefly larva.

At the current flow of 630cfs, the water was up to the bottom stone on our Angler Access and it was easy to get down to the river.  The new side channel is doing well and was widened a bit from the high flows. The banks are very sandy, making the side channel bottom sandy in areas but we found several areas with spawning size gravels. The high water moved the woody debris around, but there is still excellent woody cover and we saw trout fry scattered throughout the side channel.

Floating down into the Barber Pool, we found 4 areas that had large deposits of gravel that look to be great trout spawning habitat. Once you get into the Barber Pool the water velocity slows down considerably and deepens. There is some bank-side woody cover that is available to fish at the current flows of 630cfs, but it may be out of the water in the winter. Water clarity in this section is much better than in town and you can see 6-8 feet.

There are 2 mandatory portages on the float from the Diane Moore Nature Center to Barber Park. The first is Barber Dam, which you portage on river right. There is a set of landscape timber stairs and then a long, but well developed portage trail around the dam site. The second is Eckert Diversion, which you also portage on the right. That portage trail is much rougher with boulders and tree roots to navigate through. Definitely best for smaller, lighter craft such as a canoe or kayak.

This Fall we will be wrapping up our angler access project, including adding hillside retaining along the path; Filling in the lower stone steps with roadmix; and Installing signage. Stay tuned for more details.

Troy Pearse
Conservation Director
Boise Valley Flyfishers
conservation@bvff.com

Ada County Parks & Waterways Master Plan Focus Group

Executive Summary of BVFF Positions

For the Focus Group Representatives

March 7 and 8, 2023

Key Messages to Convey

A. BVFF is a non-profit, member organization that promotes fly fishing through our core missions of:

• Access

• Education

• Conservation

B. Overarching Position:

Add fishing to the Ada County Parks & Waterways Master Plan as a major recreational activity and consider the impact to fish and anglers when making changes to the master plan, including prioritizing protecting and improving fish habitat that will improve fishing in the Boise River and other public waterways within Ada County

C. Reflect in the Ada County Parks & Waterways Master Plan:

“PROTECT, PRESERVE, AND DEVELOP FISH HABITAT AND ANGLER PUBLIC ACCESS TO ALL PUBLIC WATERWAYS WITHIN ADA COUNTY”

BVFF Specific Requests to be Included in the Master Plan of Ada County Parks & Waterways:

A. Protect wild trout in the DMNC/Barber Pool area by supporting catch and release regulations/size limitations, placing monofilament collectors to protect bald eagle and other wildlife, and providing wild fish habitat protection and enhancement. Also, provide and maintain public restrooms.

B. Maintain the Barber Park to Ann Morrison Park reach for unskilled water users and improve/provide the services necessary to protect the river corridor from the negative impacts of heavy traffic by: Partnering with Boise City and BVFF to add educational signage at access points for anti-litter, provide trash bags at all access points, provide restrooms along the corridor with signage as to location, provide trash receptacles at all takeout locations, and place monofilament collectors at fishing access points. In addition, partner with Boise City, IDF&G, BVFF and other organizations to repair and protect riparian areas and improve fish habitat through protection and management of side channels, promoting woody cover, providing spawning gravel, and increasing winter flows.

C. Oppose expansion of any unskilled water craft and removal of wild fish habitat or woody cover from Ann Morrison Park downriver to Ada County Line. If expansion is done, it should be for skilled water users only - Place warning signage at any access points stating that this section of river is for SKILLED BOATERS ONLY and is dangerous to unskilled water users

D. Along the Snake River corridor, support the development of a Regional Park and provide anti-litter signage, trash receptacles and mono collectors

E. Support wild trout habitat including year-round side channels, woody cover, spawning gravel, and increased winter flows in the Boise River to improve fish habitat for spawning and rearing for higher recruitment of fry

F. BVFF would like to partner with Ada County on preventing and cleaning up litter in the river by:

1. Leveraging anti-litter signs from the Diane Moore Nature Center (BVFF developed with IDFG) to major access points, such as Barber Park

2. Work with BVFF to add mono collectors in key locations where mono is a problem, such as at Barber Park where steelhead are released

3. Encourage organizations to join the Living Lands Adopt-a-River program. Support BVFF adding an Adopt-A-River sign on the Boise River downstream of Garden City Limits

Areas of Concern:

A. Increase in motorized jetboat use on the river at Eagle Island State Park into the Boise reach which is hazardous to fishers

B. The conversion of Eagle Island State Park to an Ada County Regional park might include increased unskilled floater access. Any conversion from State Park to County Park that negatively impacts trout habitat is opposed by BVFF

C. Rampant trash in the Swan Falls area. Also, monofilament line being left behind by anglers. This is a raptor nesting area, and they might use the monofilament in their nests creating an entanglement hazard

D. Boise River winter flows are too low to support side channel spawning and rearing habitat

E. Fishing is not listed as a major recreation activity in the current master plan. According to the Outdoor Industry Organization, nationally fishing is the third most popular outdoor activity, after jogging and hiking.

(https://outdoorindustry.org/wp-content/uploads/2015/03/2021-Outdoor-Participation-Trends-Report.pdf) and we expect that fishing may rank even higher in Idaho. The Boise River through town is a blue ribbon trout stream that is gaining national attention through fishing magazines. Idaho Tourism data shows that fishing is one of the top activities for tourists at twice the national rate

F. The Eagle Island (including Eagle Island State Park) north and south channels are premium trout spawning and rearing habitat and should be left in their natural wild state

Go to BVFF.com for more information about our organization.

Thank You for inviting us to participate!

BVFF Board of Directors

Members from the Boise Valley Fly Fishers Board of Directors attended Flood District 10's Retirement Celebration for Mike Dimmick.  Bill Clayton, Chairman of the Flood Department's Board recognized Mike for his efforts to join transform the Flood District and connect with the community, including calling out his work with Boise Valley Fly Fishers.  Mike has been instrumental in our two Boise River gravel augmentations, both in planning the activity and helping us wade through the permitting process as well as coordinating the effort with the Flood District's winter maintenance cycle so we could utilize their heavy machinery to move the gravel into the river. 

After the first gravel augmentation we asked Mike if the excavator driver knew how to identify and avoid brown trout spawning redds/nests. Mike said no, but they would like to be able to do that, if we could show them how.  From that we developed our Boise River Brown Trout Redd Protection Program which provides the flood district's excavator driver maps of the locations of the redds which they have been able to use to avoid the spawning zones.  

As a token of our gratitude for all of Mike's help, the BVFF Board of Directors presented Mike with a handmade fishing net with his name engraved along with a Lifetime Membership to the club.  For more information about Mike's work at the flood district, see this article in the Capital Press .

BVFF is already working with the new District Manager, Mark Zirschky, who is very supportive of our efforts and wants to continue working with Boise Valley Fly Fishers on Trout Habitat Improvement and Protection on the Boise River.

(Steve Stuebner Photo)

SPRING 2023 RUNOFF

HIGH FLOWS

The Boise River experienced high runoff this spring with flows staying above 4,000cfs for 2 months and reaching “bank full” flows of 6,000cfs for 2 ½ weeks. High runoff is a healthy part of the lifecycle of a river as it helps clean the bottom of accumulated debris and improves trout spawning habitat by redistributing smaller gravels. On a naturally flowing Freestone river, high water refreshes trout spawning habitat with new smaller gravels from upstream, however, on a Tailwater river like the Boise River, these new smaller gravels get trapped upstream behind the dam (Lucky Peak) which keeps them from refreshing the trout spawning habitat below the dam, which is why BVFF and TU have been doing gravel augmentations in the Boise River.

At "bank full" flows, the Boise River does harvest some smaller gravels from the banks and islands which improves trout spawning habitat in some places. We will be able to quantify that this fall when we do our annual Brown Trout Redd Counting and Mapping project. It will be very interesting to see how the high-water event impacts brown trout spawning, but my expectation is we will see an increase in the number of redds on the Lower Boise River.  Watch for our Brown Trout Redd Surveys this Fall and come see for yourself!

GRAVEL AUGMENTATION

In February of 2023 BVFF added 15 cubic yards of spawning gravel on the inside bend of a side channel of the Boise River. On a normal runoff year we would expect most of the gravel to stay on that inside bend, but on a high water year like 2023 Mother Nature is going to relocate it downstream (Mother Nature knows what she is doing and is very good at placing it in locations that are suitable for trout spawning). The below photos show the gravel augmentation location at winter flows (250cfs), in May at 6,000cfs, and then in August at 650cfs. At 6,000cfs you can see water coming into the side channel across a wider area, but the river velocity is still significantly less than the main river channel and there are plenty of soft-spots behind the woody cover for trout to shelter.

GRAVEL RELOCATION

Flows on the Boise River recently dropped to 650cfs (a very fishable flow!!) and I walked the side channel to see where Mother Nature decided to relocate our gravel. The good news is that the gravel is still in the side channel and Mother Nature left it in good locations for trout to use for spawning! The figure below shows the side channel, the gravel augmentation location, and where new gravel has accumulated. It is impossible to identify our gravel from natural gravels, but I can say that there are significant new deposits of small gravel about 500 feet downstream of our augmentation-zone, below where the side channel has an “S Curve”. This is a typical location for the river to drop gravel as they like to drop it on the inside bend where water velocity is reduced, which is one reason why sinuosity is important to a healthy river (sinuosity is a measure of how many curves a river has). And because the flows were so high, some gravel was dropped above the normal summer high water mark, leaving a kind of “bathtub ring” in some locations. This bathtub ring effect can also be observed in the entry area of the side channel from new gravels being dug up from the water spilling over the banks.

WOODY COVER

As a part of our trout habitat improvement work on the side channel we worked with IDFG and the Boise Flood District to incorporate woody cover to give trout fry shelter (shown in the figure above and the photo to the right). Woody cover is just as important to improving the trout population as spawning gravel. Early observations this summer have shown some rainbow trout fry in the side channel and we hope to join IDFG on their annual Trout Fry Survey later this fall to see how the juvenile trout handled the high flows. The large pieces of woody cover that were anchored are still in place but some of the smaller pieces were carried away by the high flows and could use to be refreshed and anchored.

The high water event left some debris at the entry to the side channel and broke through the nearby New Dry Creek diversion dam, dropping the water level and reducing flows into the side channel. At 650cfs we are getting about the same inflows to the side channel as we did at 250cfs last winter. We will be doing some maintenance on the side channel in August to help clear debris to improve inflows and improve the woody cover. If you are interested please sign up for the event posted on our website. 

TERRAFORMING

Below are some examples of how Mother Nature “terraformed” the side channel and where she moved our gravel. There is now good spawning gravel in the S-Turns and the tail-out below that. Before high water there was a 100' long narrow trench with a bottom of large cobble. That trench is now filled with spawning gravel and is an awesome long spawning run!  Some of these locations are more suitable to rainbows to spawn at higher flows and others are perfect for brown trout spawning at lower flows.  We will continue to monitor the side channel for spawning activity and report what we see.

THANKS FOR THE HELP, MOTHER NATURE!

Please welcome BVFF member Johnny Rogers as the new Leave It Better Lead. He replaces Brian Martin who has moved into the role of BVFF president. Johnny has been a member since December of 2021 and has volunteered for many projects including river cleanups, Diane Moore Nature Center access, and Expo 2023 where he posed as Eddy Trout.

Johnny Filling The Net On The SF Boise 2023

The Leave It Better Lead is responsible for coordinating our Spring and Fall "Real" Boise River Cleanups, informing us of partner organization river cleanups on the Boise and Owyhee rivers, and assisting with the Adopt-A-Stream program through Snake River Waterkeeper.

Thank you, Johnny, for volunteering for this Conservation mission role! We're here to help in any way you need.

A bill to permanently protect fish and wildlife on Owyhee River Canyonlands was introduced by Oregon legislators on June 8th.  The bill is supported by a coalition of ranchers, native tribes, anglers, hunters, and conservation groups, and will protect approximately one million acres of fish and wildlife habitat.  This Trout Unlimited article describes the bill and the support that will be needed to get it passed.

Trout Unlimited has also released a short film, produced by the Owyhee Sportsmen Coalition on fishing the Owyee River, which can be viewed HERE.