RAIN CHANGES EVERYTHING: Mudflows in South Fork Canyon blocks road, inundates river, closure continues

So much for that plan to open a portion of the South Fork Boise River.

The email message from the Boise National Forest’s Mountain Home Ranger District:

Guys, due to the mudslides and ongoing instability of the area, the SF Boise River will NOT open as discussed at the TU meeting Wednesday. The area will remain closed until further notice. As of now all access roads to the SF are closed. Again the area is closed to everyone except Federal, State or County personnel in performance of official duty.  

The rain gage at Anderson Ranch Dam recorded more than 0.6 inches of precipitation on Thursday evening September 12.  This piece of data portended the mudslides, gullywashers and mass failures that have inundated the South Fork Boise road and reached the river in many locations.  For example the photo below from KTVB.com shows a big mudslide.

Mud slide across South Fork Boise road just east of Reclamation Village. Photo from KTVB.com website

News coverage with some photos can be found at the Idaho Statesman and at KTVB websites.  There is also a very good overview news release from the Boise National Forest here.



Fire Effects Discussed; Partial Opening of River Imminent; Stranding Study Slated September Sixteenth

Good attendance for community meeting on South Fork Boise River

Approximately 75 people made it to the MK Nature Center Wednesday Night to get the low down on the effects of the wildfire that affected the South Fork Boise River.  The audience got a dose of information where things stand with the South Fork.

Mountain Home District Ranger Stephaney Church said she is working to open the section of the South Fork of the Boise River from the Cow Creek bridge downstream.  Perhaps as soon as this weekend.

Church said the section of the river was less affected than from Anderson Ranch Dam to Cow Creek.  This website back on August 21 showed the extent of the fire in the lower section of the river.  There were fewer trees burned along the river and therefore less work to be done to cut down the trees that could be a safety hazard.  Further upstream its a different story and it will take much longer to assess the safety hazards and do something about them.

One questioner missed badly when stating that everyone attended the meeting just because they want to know when the river will be open again to fish.  Visits to this website and discussions among the fishing and conservation groups show otherwise, as there is significant interest in the long-term future for the South Fork fishery and for the river ecosystem.

Dick Frencer of Boise Valley Fly Fishers poses a question to Stephaney Church

Agency staff with the Forest Service, BLM and Idaho Fish and Game described the effects of the fire and the field assessments done so far so a game plan can be developed to address the most immediate needs for emergency rehabilitation.  While the meeting discussion was at a more general level, some specifics have emerged.  For example, the Elk Complex fire north of the river experienced much severe burning and the effects on soils in some locations appears fairly dramatic.  We are keeping an eye on Pierce Creek, Granite Creek and Rough Creek.  All three drain into the South Fork of the Boise from the north side.  Granite Creek in particular could be a ticking time bomb with a small culvert and a watershed that appears to have seen severe fire effects.  Pierce Creek of course no longer has a small culvert but rather a new bridge, so if there is a gully washer one hopes the flows and debris should be able to pass under the bridge.

Meanwhile the stranding study will proceed with government agency staff biologists on Monday, September 16 when the South Fork Boise River flows will drop to 300 cfs.  Idaho Fish and Game and the Bureau of Reclamation will have staff on site to ascertain the amount of stranding when the river flows are cut.  This information will help inform future management changes with river flows.

South Fork Boise Community Meeting September 11th

In the wake of the Pony Complex and Elk Complex Fires and their destruction of substantial habitat along the South Fork of the Boise River downstream of Anderson Ranch Dam, the Ted Trueblood Chapter of Trout Unlimited is organizing a meeting to serve as an open forum for all those concerned at 7:00 p.m. on Wednesday, September 11th, 2013 at the MK Nature Center.

Rock garden and Pine Tree Hole

We believe that it is essential that we work in collaboration and cooperation with our government agency partners in a supporting role. In our view, once they determine the strategy/way forward, priorities of work and requirements, we can then mobilize our constituents and resources to help.

There remain a lot of unknowns and we understand that the assessment of the extent of the damage will not be complete for a number of weeks. As an initial step by those of us in the community, this open forum meeting will include agency representatives to provide information on the post-fire habitat condition of the South Fork of the Boise River. It will provide the opportunity to discuss where we are today, where we think we are going, what we think is needed, and how we might help.

Fire History in the South Fork

While wildfire in on the mind here’s an interesting map where we clipped the portion of the Boise National Forest showing the fire history of the South Fork of the Boise River.

Clipped from fire history map of the Boise National Forest 1908 - 2013

Downstream of Anderson Ranch Dam there was a fire on the north side of the River in 1948 but it appears the rock bluffs on the north side were a barrier in that portion downstream from about Reclamation Village to Granite Creek.

Further downstream on the north side there was a smaller fire in 1952 that appears to have affected the lower portion of the Pierce Creek watershed, including the Prairie Road switchbacks where it climbs from the canyon on its way to Prairie.  This 1952 fire appears to be on the south side of the South Fork Boise downstream of the Danskin Bridge and through much of the Mennecke Creek watershed.

On the south side of the River just downstream of the dam for a couple of miles appears to be outside any historic fire perimeter.  There does appear to be a section that burned in 1935, which may have burned again in 1942.  Adjacent to the west is a larger fire area that encompassed the Cow Creek drainage, and the lower portion of the Cow Creek road as it drops into the canyon appears to be a perimeter on the 1926 fire.

To the west is a fire from 1986 was that was probably a reburn of some of the 1926 fire area.

Underlying this area is the 1992 Foothills Fire, extending from the Cow Creek road and along the south side of the South Fork Boise through the meadow area and approaching the rick garden and Pine Tree Hole near Granite Creek.  So it encompasses much of Cayuse Creek, a small tributary on the south side.

This is the light green area sandwiched between the 1926 fire area to the east and the 1945 fire area to the west.  The 1945 fire appears to have been in Mennecke and Bock Creeks. By the 1970s both Mennecke and Bock Creeks were noted to be tributary spawning sites for the South Fork fishery.


Stream Gages destroyed by Wildfire

Here is a video from the USGS with the story about the Pony & Elk fires destroying the stream gages on Dixie Creek and Pierce Creek, two tributaries of the South Fork of the Boise River downstream of Anderson Ranch Dam.


In addition, the end of the video has links to the stream gages click here for Dixie Creek, or check out this link for the gage at Pierce Creek.