South Fork Opens November 6th

From Boise National Forest news release:

Open areas include the South Fork Boise River, downstream from the Anderson Ranch Dam.  Recreation along the river corridor is open to day use only, and overnight use is prohibited.  Floaters are advised that the river has substantially changed with new channels, flows and large trees in the river.  

 

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South Fork Recovery Begins with You November 9th

Make plans for Saturday November 9th for volunteer planting along the South Fork Boise River to kick start the recovery of the river corridor from the recent wildfire and mud flow events.

The plan is to meet at the parking lot near Albertsons near Federal Way and Gowen Road (next to Exit 57 on I-84) at 8:30 a.m. We will organize those who want to car pool and to leave promptly at 9:00 a.m. for the drive to the South Fork of the Boise.

Thanks to the more than four dozen people who signed up to volunteer at the September 11 meeting we think we will have a core group to start.  But additional help is needed for this effort.  We are working to get the word out with the fly shops and the fishing clubs.  The Boise National Forest is determining what plants and trees will be planted, they types and quantities. Needed tools are being identified.  At this time we need you to sign up to help. You can call Bob Caldwell at (208) 322-5539 and leave a message or email BandDCaldwell@gmail.com.

There are several areas where the debris flows scoured the gound the removed vegetation.  These areas will be one to plant.  Other sites where the fire burned may also need planting, but in many cases we are already seeing willow begin to regenerate on its own from the roots that were not killed in the fire.

Knowing in advance how many people are coming will help planners determine how much we can get done.  Lunch will be provided on site.  And, there is not Boise State football game on November 9th so don’t worry about that potential conflict.

Shutdown stalls South Fork recovery activities

The Federal government shutdown that started October 1 has thwarted any movement towards long-term recovery of the South Fork Boise River.  And any decisions about opening the river or a portion thereof to fishing has also been stymied.

While so-called “essential” staff are still on the job (without pay), which includes fire, law enforcement and burned area emergency rehabilitation activities, other Federal government professionals are not.

Deep-rooted cottonwoods like those in the tub at Lucky Peak Nursery are available for planting. L to R: Matt Perkins, City of Boise nursery; John Sloan, Lucky Peak Nursery; Pam Harrington, Trout Unlimited; Clark Fleege, Lucky Peak Nursery

Discussions in late September identified the potential for planting cottonwoods in some areas along the South Fork Boise River.  Cottonwood cuttings taken from South Fork Boise River have been growing at the Boise National Forest Lucky Peak Nursery, and several dozen of these trees could go in the ground before the snow flies to begin the long-term recovery effort for the South Fork.  The meeting to decide when, where and what to plant would have happened October 1st or 2nd, but the government shutdown slammed the door on this little initiative.

Conservation groups had approached the Boise National Forest about the  idea to do some planting along the South Fork.  The Forest is very interested in using some volunteers and have identified some areas where planting can do some good, and where it would be safe to have volunteers do some work.  Not only that, the cottonwood trees are at Lucky Peak Nursery, ready to be put in the ground.  But until the government shutdown is over little can be done about it.

Granite Creek blowout washed away the hill side. Perhaps a good location for some cottonwood trees?

Once the shutdown is over and some progress gets made on a planting project we will provide an update at this website.

 

 

The 2013 Weak Water Year

We grabbed a few charts at the end of Water Year 2013 to put some perspective on the water situation.

Flows from Anderson Ranch Dam:

Flow From Anderson Ranch Dam where blue line = 2013, green line = 2012, red line = long-term average

The summertime flows were 1,600 cfs instead of 1,800 cfs in 2012.  The 1,600 cfs flows extended well into August to provide irrigation water to users in the Treasure Valley.  The rest of the system was draining so more water was moved from Anderson Ranch pool.  And you can see what happened in the reservoir here:

Water stored in Anderson Ranch Dam blue line is 2013 and green line 2012 and long term average is the red line

Anderson Ranch reservoir started the water year (October 2012) very near the average for water in the pool.  The low snowpack in the winter meant less runoff into the pool in the spring and early summer.  The peak amount of water in May was nowhere near the average, let alone filling Anderson Ranch.  The the 1,600 cfs flows pulled the contents to an amount well below average and at a high rate until mid August.  The water year ends with 100,000 acre feet in the pool.

The reservoir drained very quickly because it was a year where much less water flowed into Anderson Ranch Reservoir as seen in the chart for the water gage at Featherville:

Water flows on South Fork at Featherville gage with 2013 in blue, 2012 in green and average in red

So the blue line in the chart above shows just how below average the flows were upstream of Anderson Ranch pool.  By the way, the spike in river flows in late April 2012 on the green line is a same time when a record flow was observed in the Middle Fork Boise River at Twin Springs gage.  Some readers may recall the late April heavy rains that  melted much of the lower to mid elevation snow into the South Fork Boise River.

One indication of the water year ending in a whimper is what happened with the flow gage on the South Fork Boise a mile or so downstream of Anderson Ranch Dam:

River flow data in late September 2013 was affected by the landslides into the South Fork Boise

The slides on September 12, 2013 knocked out the water gages for a few days.  They are back running now, but the chart above from September 24 shows only a brief period when it was working that day and no data was charted for previous days.  This situation is understandable given that much debris tumbled into the South Fork and it may have directly affected the functioning of the gage or perhaps changed the profile of the channel in the area of the gage making a clean reading of water flows a challenge and thus a need to recalibrate the equipment.  The automated system for this gage is working as shown on the USGS gage here.

Looking forward, there have been some inquiries and informal discussion whether it would be possible to shape flows from Anderson Ranch Dam in 2014 to deal with the debris and sediment in the South Fork Boise River to help transport the sediment and allow the river to carve a channel through the massive deposits in the river.  For any of this to happen it will require water in Anderson Ranch pool that is not yet there.  A winter with above average snow could be very important to developing some alternatives to shape the flow releases, their timing and magnitude, and it will have to happen without adverse effects on downstream water users.  But readers may be interested in knowing it is a topic of conversation, or at least was prior to the government shutdown.

 

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AS DESIGNED: Pierce Creek Bridge Weathers the Storm

Pierce Creek bridge on September 13

Longer-term visitors to this website may recall seeing stories when the Pierce Creek Reconnection Project started and completed and the role tributaries play in maintaining a fishery.

The mud and debris flows from Pierce Creek on September 12th were both substantial in amount delivered to the South Fork of the Boise River and unique in that the entire flows went under the bridge.

This was by design because when the project went forward in 2011 project engineers used data on the high flow estimates for Pierce Creek.  And while not to spike the ball in the end zone or anything, it is satisfying to see something perform pretty much as planned.

But the story is not over.  There could be more weather events that cause more flooding with a similar mud slurry.  And there are lasting effects from the September 12 event that will need repair to the stream channel.

While the slurry was confined to under the bridge many of the grade control structures in the channel were swept into the river.  Here is how the channel looks today:

Looking downstream from Pierce Creek bridge September 16, 2013

Many boulders are covered in mud but many are also now in the South Fork of the Boise River.  A large drop in the stream bed as seen in the foreground (bottom of the photo) did hold in place as that large boulder is part of the channel that was in place prior to the removal of the culvert in 2011.  The vertical drop creates a barrier to fish wanting to move upstream.

Compare the above photo with that from early 2012 just prior to planting the site:

Early spring 2012 showing the step pools in Pierce Creek

The right bank of Pierce Creek through the trees was scoured of nearly all the brushy vegetation, brush that is clearly visible in the 2012 photo.  Meanwhile the plantings on the left bank are still in place after the mud flows.

So work will be done to shore up the grade control of the stream and make it possible for fish to be able to move freely upstream and downstream in Pierce Creek.  Thanks to a generous donation of time from Quadrant Consulting the field survey work will commence later this week.  We salute Quadrant’s contribution to the South Fork fishery!  As survey work transitions to construction we will provide updates.