Flows Remain Low This Spring

Posted by admin on May 13, 2022   |   No Comments

Wow, it’s mid-May and the flows from Anderson Ranch Dam remain at the winter minimum 300 cfs. Normally this time of year the flows in the South Fork Boise River will be running 600 cfs. As the chart below shows, last year the flows increase from 300 cfs to 600 cfs on April 1, 2021.

Screen grab from the Bureau of Reclamation webpage.

The last time that 300 cfs flows extended into the spring spawning season was 2014, which came after the 2013 debris flows that had covered much of the South Fork Boise in sediment. A double whammy! The flows increased in early June as this chart from a previous post in 2014 showed:

Note this chart only runs to 2014. It’s what we had in the media file.

One result of the 600 cfs flows in the spring months is it waters up some side channels and allows some rainbow trout spawning in those locations. At 300 cfs we probably have less spawning areas available.

Why is this happening? There is a pretty good reason. The Boise River reservoir system is below average in water because last year was so hot and dry and until the last few weeks the snowpack was below normal. And, Anderson Ranch Reservoir sits highest upstream in the Boise River basin among the storage reservoirs and the water stored highest upstream is most valuable for future uses. As the graph below shows, Anderson Ranch is filling, maybe a little faster than it filled last year, but the total contents are still well below both long-term average and last year as well.

The flow of 300 cfs since April 1 being half the normal rate means so far some 25,000 acre feet more water in the reservoir then there would be if the flows were at 600 cfs.

Currently Anderson Ranch Reservoir is approximately half full and the downstream Arrowrock and Lucky Peak projects are well above half, with the natural flows from the Middle Fork Boise River poised to fill those pools when the snow melt starts in earnest.

What are the implications for the fishery? There may be less spawning, or survival from it, in the mainstream river this year, versus when the river flows at 600 cfs. It also points to the importance of the tributaries that can contribute more spawning habitat with actions to improve access (where culverts may inhibit fish passage) and improved habitat. A balance of both mainstream and tributary spawning is necessary or balance the risks to the population.

New South Fork Boise Video

Posted by admin on October 15, 2021   |   No Comments

The Idaho Rangeland Resource Commission has produced a new video on the South Fork of the Boise River. The video urges responsible recreation behavior as the area continues to see increased use.

Anderson Dam Raise Open House

Posted by admin on August 27, 2019   |   No Comments


The U.S. Bureau of Reclamation (BOR) is considering raising the Anderson Ranch Dam on the South Fork of the Boise River.  They have formally opened the process to prepare an Environmental Impact Statement for that project. The following notice was published in the Federal Register https://www.usbr.gov/pn/studies/boisefeasibility/noisigned.pdf  You now have an opportunity to learn more about the proposal and the public process by attending any of three open houses, and to provide your personal comments to the BOR on the potential impacts of the project. Trout Unlimited’s formal written comments are currently being drafted and will be submitted in September.

Locations/Dates/Times
The public scoping open houses on the EIS are as follows:

Tuesday, August 27th,  1:00-3:00 p.m.
Boise River Senior Center, Pine, Idaho

Wednesday, August 28,  6:00-8:00 p.m.
Wyndham Garden Inn, Boise, Idaho

Thursday, August 29,  6:00-8:00 p.m.
American Legion, Mountain Home, Idaho

Written comments:
Must be submitted by 5 p.m. on September 9, 2019, by email to BOR-SRA-BoiFeasibility@usbr.gov

Why should you attend and comment?
A law passed at the end of 2016 gives BOR the authority, and likely the funding, to proceed directly to construction upon completion of the studies.  This is the time for you to learn more about BOR’s plans and for you to express to BOR the importance of the South Fork of the Boise River fishery. You can request that they explore the following issues, among others, in the environmental impact statement:

  • How would this dam raise impact winter flows for fish both in the South Fork and the Boise River through town?
  • Will spring flushing flows be affected?
  • How much will it cost to raise the dam and will other, possibly less expensive, alternatives be considered such as water conservation or efficiency projects?
  • Will opportunities to provide additional water storage for winter fisheries flows be considered?

Questions?Please email Peter Anderson at:
Peter.Anderson@TU.orgor call Kira Finkler, Michael Gibson, or Peter Anderson at the TU Boise office, at 208-345-9800.

Dispatches from Pierce Creek

Posted by admin on April 14, 2019   |   No Comments

The March 30 planting project is done.  Here’s a round up of photos and observations.

The Forest Service assigned five personnel. They provided instruction, equipment and leadership on the ground. They praised us saying we knew how to through a good party. They may be able to partner with new projects this season and promised to keep me in their loop. Barber Flats interestingly is a target.

With last minute unanticipated subtractions and additions TU contributed at least a dozen and a half to two dozen persons including the cooking crew. Weather was perfect. Kudos to Fred Hebert and his two buddies for a chili based lunch with our kitchen equipment. They gave Leadership credits to one Eagle Scout.

Boy Scouts (BSA) will monitor “take” during the summer. FS will share details with us.

The BSA swelled our ranks immensely with scouts and their family members. There were easily four dozen persons all actively cutting and planting from 11:00 a.m. to 3:00 p.m. sans 45 minutes for lunch. Together we all placed literally hundreds of 12 to 18 inch pieces into the embankments along Pierce Creek both below and well above the bridge and even under the bridge and around wattles FS had installed earlier to bank retard erosion near the bridge. Rain is anticipated now soon to follow this week that should help.

I would like to add to Dr O’s report the planting went really well and Doug did show and there were probably several other members that showed also who didn’t send in emails but may have been on some of the other lists.  Every one got fed well and there was no food left to clean up Fred was able to get a few of the scout to take seconds to polish off the chili.

The Forest Service did an outstanding job in mitigating the impacts  of the migration barriers left after the initial big blowout the willows initially planted were well established below the bridge.  There is a potential barrier where the creek drops off the alluvial fan into the South Fork that will probably change after high water this year.  If BOR doesn’t start releasing water very soon we will probably seem some very high water on the SF later this spring.

I did stop below the tailwater put in to see what the talk was on the so called alternate put in was about.  I don’t think it is a big deal yet.  It is a very steep high bank and only soft boats can be launched there You have got to want to fish that section pretty bad to put a boat down that bank.  At the 600cfs that the river was at there was a route thru the rapid.  There was at least one must make move a weaker boatman would probably not want to run it at this level or lower, once the river comes up it should open up and be plenty of room just some big waves and maybe a hole to stay out of.

Over all it was a good outing couldn’t beat the weather

March 30: Pierce Creek Riparian Planting

Posted by admin on March 21, 2019   |   No Comments

A final step in restoring Pierce Creek will happen on March 30, 2019 and we need volunteers to make it reality. Planting the streamside area around the rebuilt bridge at Pierce Creek (on the South Fork of the Boise River, near the Danskin boat ramp) will stabilize the stream bank of this important habitat.

The Pierce Creek Bridge was installed in 2011 and the footings were then rebuilt in 2018 after watershed debris flows undermined the foundation. This project was inspired and led by Trout Unlimited, working with the Mountain Home Highway District and the Boise National Forest. With a bridge replacing a culvert on Pierce Creek, the free passage of wild trout and other fish species is secured for this tributary to the South Fork Boise River.

Join the contingent of volunteers to help finish the job at Pierce Creek.

The particulars:

  • Saturday, March 30, 2019.
  • Meet at the Albertson’s parking lot at Federal Way and Gowen Road between 8:30 a.m. & 9:00 a.m. We will make carpool arrangements and leave from there at 9:00 a.m. and carpool to the South Fork Boise River.
  • In the morning we will gather willow cuttings at locations along the South Fork Boise River.
  • In the afternoon we will plant the cuttings in the bank along Pierce Creek.
  • Lunch will be provided by Ted Trueblood Chapter of Trout Unlimited, using our eager and experienced cooking crew and equipment from our summer Trout Camp.
  • Total work time is estimated to be four to six hours. Mid-afternoon return to Albertson’s in Boise.
  • Bring work gloves.  Bring a folding chair if you have one for sitting at lunch.
  • Please RSVP to Bruce Johnstone at BJohnstone1@cableone.net by Thursday March 28.