The Idaho Batholith
September 22nd, 2007
The Yellow Pine Fire, a complex of fires that occurred this summer in Idaho (see here) has burned over 750,000 acres (1200 square miles) directly atop the Idaho Batholith.
From the Digital Atlas of Idaho (here):
The Idaho Batholith is a composite mass of granitic plutons covering approximately 15,400 square miles in central Idaho. The outer perimeter of the batholith is irregular and in plan view it has an hourglass shape. It is approximately 200 miles long in the north-south direction and averages about 75 miles wide in an east-west direction.
Batholiths are made of granite and are prone to mass wasting. From the Wikipedia (here):
Batholiths exposed at the surface are also subjected to huge pressure differences between their former homes deep in the earth and their new homes at or near the surface. As a result, their crystal structure expands slightly and over time. This manifests itself by a form of mass wasting called exfoliation. This form of erosion causes convex and relatively thin sheets of rock to slough off the exposed surfaces of batholiths (a process accelerated by frost wedging). The result is fairly clean and rounded rock faces. A famous example of the result of this process is Half Dome, which located in the world-famous Yosemite Valley.
Not only is the parent rock easily weathered, batholitic (granitic) soils are highly erodable. From an article in Erosion Control Magazine, March/April 2001 by Roberta Baxter (here):
In central Idaho, the Clear Creek fire [on the Salmon-Challis NF] burned more than 200,000 acres, “the largest fire in 2000.” … In some areas, the Forest Service has shored up roads so they won’t be washed away or undermined by erosion. Along the Salmon River the vegetation burned, so the river fills with mud after a rainstorm.
Increased erosion after a fire results from removal by incineration of the ground cover, including the tree canopies that intercept direct rainfall. In addition, cooked soils have more water repellency, which reduces water infiltration, increases runoff, and thereby also increases erosion. Studies have shown that sedimentation in streams can increase by a factor of seven (or more) after a fire (here):
Forest Fire Effects on Hillslope Erosion: What We Know
by Peter R. Robichaud, USDA- Forest Service, Rocky Mountain Research Station, Moscow, Idaho
DeBano et al. (1996) demonstrated that following a wildfire in ponderosa pine, sediment yields from a low severity fire recovered to normal levels after three years, but moderate and severely burned watersheds took 7 and 14 years, respectively. Nearly all fires increase sediment yield, but wildfires in steep terrain produce the greatest amounts. Noble and Lundeen (1971) reported an average annual sediment production rate of 2.5 t ac-1 (5.7 Mg ha-1) from a 900 ac (365 ha) burn on steep river breaklands in the South Fork of the Salmon River, Idaho. This rate was approximately seven times greater than hillslope sediment yields from similar, unburned lands in the vicinity.
The upshot? The Yellow Pine Fire denuded hillsides and cooked soils across hundreds of square miles of the Idaho Batholith, and the erosion this coming winter is going to be colossal, stupendous, and beyond anything ever seen in Idaho’s history.
The mud will come flowing down creeks and streams in the South and Middle Forks of the Salmon River, increasing turbidity and burying spawning gravels. Top soil will become silt. The denuded hillsides will become riverine mud banks.
The Payette and Boise National Forests will flow to the sea, or at least to the nearest slack water.
Logging has been enjoined on the Payette and Boise NF’s for many years due to the potential for increased erosion. Even delicate, partial-cut, Healthy Forest Restoration Act projects have been kiboshed. Those projects were slated to cover only a few hundred acres, anyway. The 1200 square miles roasted this summer dwarf the handful of micro-mini-nano projects rejected by “environmentalists.”
Wait until they see what megafire does to the environment. Or maybe they won’t see, because they don’t wish to look.
Roasted forests, fried wildlife, cooked soils, and mud in the creeks; this is the “forest health” imparted by the USFS to the public lands on the Idaho Batholith. You could say the environment has “taken a bath,” but that would be a bad pun and a gross understatement.
The forests of the Payette and Boise National Forests will never recover from the “healthy” treatment received this summer.
But just you watch. The enviro nuts will soon be out in full force declaring the blackened, dead forests are beautiful, and full of snag-loving wildlife, and the sediment-filled streams are just fine, and everything is just ducky, and why don’t we do it again next year?
That’s what passes for forest management in this our post-modern age: nutball declarations at total odds with reality, but in perfect concert with political power broking.
You lose, the forests lose, the rivers lose, the near-by communties lose, but the politicians and their supporters will win. Hooray for holocaust, vote for me.
Meanwhile, the Idaho Batholith will shed tears, and millions of tons of soil.
September 24th, 2007 at 11:05 am
So, we put out fires too long, brush and trees grew up, now combined with drought and warming temperatures we’re surprised that we’re seeing fires??
And the solution to log it all? How many years would that take?
Seems like restoring some semblance of natural fires does make sense.
If people choose to live in the woods, they need to take some responsibility. Obviously the feds shouldn’t let people and homes burn up, but fewer than a dozen structures were burned throughout Idaho this year and 2 million acres were burned.
How long would that’ve taken if we wanted to punch roads in and logged it?
Don’t get me wrong some logging and thinning makes sense in the right places, but fires can do alot of that work for a lot less $$.
Finally, the notion that these fires cooked everything in their path is patently false. The fires burned with mixed intensity, some hot, some cool.
You’re rhetoric burns like a wind-driven red-hot fire thou, fortunately anyone who reads your stuff realizes you’re far enough out there not to make a real impact.
September 24th, 2007 at 11:34 am
Seth — Where in the world did you get the crazy notion that I recommend that we “log it all”?
There are over 650 posts on this website. NEVER, not once, have I recommended that we log it all. That is a foul canard, a baseless accusation, and pure crap.
I have consistently recommended restoration forestry. Take a look, chump.
And as to your dismissal of my influence, you are sadly mistaken about that, too. SOS Forests is the premier forestry website in the Blogosphere. Movers and shakers read this site. And what’s more, they AGREE with 99 percent of what appears here.
What they DON’T agree with is simple-minded hysterical rhetoric about “logging it all” as the ONLY solution to our forest destruction crisis. Nobody thinks that, Seth.
You are trying to make a straw man. You want everybody to think that some vast capitalist conspiracy wants to clearcut the National Forests. That’s a lie, Seth, and you should know it.
What we are trying to do here is SAVE our forests from destruction. Where did the fires “save” forests, or make them “healthy,” or “do the work” of forest restoration? Send us a map and some pictures, Seth. Then we can check your assertion out, and see if your remark has a scintilla of truth to it.
You can’t, because it doesn’t.
And by the way, Dear SOSF Readers, I did not make Seth up. He is, as I predicted, an enviro nut attempting to justify the worst disaster in Idaho NF history.
So I was right about that, too.
September 24th, 2007 at 1:13 pm
Mike:
Maybe you didn’t make Seth up, but you should give him a break. Anyone who makes nonsensical claims such as : “but fires can do alot [sic] of that [logging] work for a lot less $$” should be treated with sympathy, not derision.
(Fires, Seth, don’t do any logging “work” at all, much less do it cheaper. Logging, if designed correctly, produces an income. Fire does not. Given that perspective, based on facts and historical documentation, the rest of your assertions become suspect or silly.
How many homes destroyed by logging last year? How many acres of old-growth killed by logging vs. killed by wildfire? Same with spotted owl habitat and spotted owls themselves? And so on.)
Give the guy a break, Mike. He needs patience and instruction, not ridicule, and that is why he is reaching out and sending you these cries for help.
September 24th, 2007 at 2:15 pm
Hey, Bob, I didn’t ridicule him, except to call him a chump and an enviro nut, which pretty tame for me.
He accused me of ignorance and flaming rhetoric, and called SOSF “far out” and of no consequence. So I feel like a counterpunch was fair.
Moreover, this post was about erosion and habitat destruction, not rural homes burning down. Seth wanted to change the subject, a common tactic of the enviro radical crowd.
The subject of this post is the Idaho Batholith. If anybody wants to discuss that topic, the floor is open.
September 24th, 2007 at 2:49 pm
Good response. That Seth! However, in defense of my own post, I believe phrases such as “simple-minded hysterical rhetoric” can be construed as ridicule.
Your erosion prediction should be fun to check out. Will anyone be monitoring or measuring in an official capacity on this? The first Fall rains should be a good indicator, and Spring snow-melt should give an answer.
September 24th, 2007 at 2:51 pm
Okay, I apologize to Seth. But really, he should have apologized to me first.
September 30th, 2007 at 7:32 pm
Re: erosion…”Will anyone be monitoring or measuring in an official capacity on this?
Mike: Impacted municipal water districts and ag irrigation or local conservation districts might be a good start if they were paying attention to pre-fire/drought erosion as closely as TMDL. If not, EPA CWA watchdogs will most likely give ‘em a nudge.
September 30th, 2007 at 9:18 pm
What EPA CWA watchdogs? The EPA is a bureaucracy of paper pushers. They have no watchdogs.
The Clean Water Act mandated that CWA enforcement be done by state agencies. The states created more bureaucracies that push more paper. There is no field corps of clean water detectives policing our waterways!
Besides, what can anyone do about it now, other than watch the soil wash away? You can’t mulch 1,200 square miles. Mulching is the plan for the 3,000 acre Angora Burn to prevent eroded soil from entering Lake Tahoe. Good luck with that! But there’s nothing significant that can be done for the Idaho Batholith now.
November 20th, 2008 at 12:48 am
Mike - sadly your predictions came true. You have posted the proof on your 2007 fires photo page. Muddy rivers, entire streams scoured. Our municipal water had to be shut down after a hard rain. Roads closed for weeks, and the hills are still sliding down. Where once was a neat little frog pond is now full of silt and mud. Its been hard on the local economy, our health, safety, transportation, and of course the fish and wildlife and birds.
November 20th, 2008 at 1:06 am
Here is a good look at the batholith - along the East Fork of the South Fork of the Salmon River. March 2008.
http://www.ktvb.com/news/localnews/stories/ktvbn-mar2608-big_boulder.1af6ff3.html
The story has a few mistakes - more then 10 people live here in the winter!
Then on July 22 a half an inch of rain in a short time blew out nearly every tributary to East Fork of the South Fork and closed the road off and on until Nov 1st.
Here is the official press release from the Payette National Forest:
FOR IMMEDIATE RELEASE
Yellowpine Mudslide Update
On Tuesday around noon, the National Weather Service issued a flash flood warning for Eastern Valley County. An isolated thunder storm tracked across the South Fork Salmon River Basin in the area of last summer Cascade Complex and East Zone Fire Complex. Mud and debris flows occurred in approximately 2 dozen small tributaries to the East Fork South Fork Salmon River (EFSFSR). About 10 drainages cross the EFSFSR Road, which provides access to the community of Yellow Pine from McCall. About 6 culverts where plugged and the road is impassable. First reports came in yesterday from loggers working in the Parks Creek area west of Yellow Pine. Park Creek severely scoured from the very head of the drainage to the confluence with the EFSFSR. A large open bottom culvert was completed plugged with an alluvial fan spreading over 1000 feet up and down the road. Mud and debris at Parks Creek is reported at about 7 feet deep. The Forest Service and Valley County Roads are working together to clear debris and provide access to Yellow Pine along the EFSFSR Road. Access is currently limited to road equipment and crews. The Forest can expect further damage in fire areas if isolated summer storm develop and produce rainfall amounts that exceed one inch per hour. No reports of damage to the community of Yellow Pine, homes, ranches, or other property have been reported.
Valley County will take the lead on clearing debris off road, opening access, and restoring flows through the culverts.
NOAA-Fisheries has been contacted for emergency consultation.
Debris jams in the EFSFSR need to be assessed for potential risk to road and downstream bridges. Action will be taken where needed by County and FS.
This type of event was foreseen and funding has already been acquired and programmed.
The drinking water supply for the community of Yellow Pine was cut off for one day following this week mud flows. Boulder Creek is Yellow Pine’s surface municipal water supply. Yesterday recon indicates surface and rill erosion. High water and mud flow lines were indicated across the steep boulder field in the mid section of the drainage. The flows eventually dissipated into the boulder field. This boulder field protects the community from large debris. However, the surface water treatment plant did receive a large amount of very fine sand and organics which required the community to shut the system down and clean screens and refurbish sand filters.
(sorry for the double post.)