fwd: massive landslide threatens Headwaters

Scott McPhee hyphae at msn.com
Fri Feb 20 02:31:33 EST 1998


> The houses below the bluff at Rio Nida(?) shouldn't be there either.

Rio Nido is about a half hour away from me.  Along with the houses in Rio
Nido, the houses down the road in Guerneville that flood every single year
should not be there either. I can not fathom why people rent these places
out EVERY year.  Do the owners forget to mention that little detail??!


Michael Hagen wrote in message <34ECD410.85DF68D2 at olympus.net>...
>Hmmm,  I've learned a few things in the last week. Never upgrade your
browser.
>Don't bid a floodplain cruise in spring.  Don't explain geotech .
Sometimes things
>just happen.
>It  sounds to me like your freeway slide was likely, maybe even guarenteed.
The
>slope was undercut. The road at the bottom ensures that the material that
rolls off
>the hill is removed, preventing a more stable angle of repose from
developing.  The
>fire killed the roots holding the surface soil in place. It may have
changed the
>slope's capacity to hold both surface and groundwater. It rained hard,
making the
>soil heavier, less cohesive and lubricating buried slip zones.  Pointing to
a
>single cause of the slide is easy to do, but probably not accurate.
>
>Prevention?  Maybe they shouldn't be logging in an el nino year at
Headwaters. I
>suppose the freeway shouldn't have been there. The houses below the bluff
at Rio
>Nida(?) shouldn't be there either.  It might have been the human activity
that
>messed things up but other reasons may have contributed as well.
>
>CamillaH wrote:
>
>> On 2/16/98, larryc at teleport com wrote:
>>
>> >It can be tricky to establish causality in natural events.  Landslides
>> >are particularly tough, since there's no way to observe what is
happening
>> >under several feet of dirt and rock.  If you see a bare slope slide, did
>> >the slide happen because the slope was bare?
>> >
>> >There has been a lot of recent research on this, since with urban
intrusion
>> >into rural areas more people are at risk than they used to be.  Instead
>> >of just flying over and taking pictures, they actually sent geological
>> >engineers in on the ground to see what was happening.
>> >
>> >Current results indicate that the slide did not happen because the slope
>> >was bare.  Slides also happen just about as frequently on slopes covered
>> >by trees.  They have been underreported from the air because the trees
>> >move right along with the slide, and cover up the signs of damage from
>> >above.
>> >
>> >However, the recent reports indicate that roads DO cause landslides.  It
>> >may be that the landslide that covered up the freeway was caused by the
>> >freeway at the base of the slope.  It may be that a fire road built
during
>> >the fire fighting effort caused the slide, or maybe a decades old
logging
>> >road finally cut loose.  Or maybe the slope was just ready to slide, and
>> >went because it rained and made the dirt heavy.
>> >
>> >The fire may have caused some surface erosion, but it is unlikely that
>> >it caused the slide.  You have too many other culprits sitting around
>> >looking guilty.
>> >
>>
>> Sorry to drag this out, but I really want to understand.  The slope that
came
>> down near my home was largely bare slope (actually rock & dirt nearly
vertical
>> grade) for a long time.  The freeway was cut into the side of the
mountain.
>> The grade was severe enough that there was another slope between the west
>> direction and the east direction of the freeway.  Prior to the fire, at
the top
>> of the mountain, there were trees, brush and grasses.  So, with the
vegetation
>> gone from the top of the mountain, the rain going onto and running off
the
>> "fire bare" land wouldn't likely have produced a landslide?   Despite the
fact
>> that the freeway had been there for decades, the fire only occurred a
short
>> time before, and heavy rains no doubt did make the dirt heavy, there is
no way
>> to establish causation to this slide?   I'll have to take your word for
it if
>> you say yes, but it seems common sense that much of the rain that made
the dirt
>> heavy would have been absorbed by the vegetation had it been there.
(BTW, the
>> mountain started sliding again in the latest rains.)
>>
>> The other point that is confusing me is can government do anything to
even try
>> to prevent catastrophic landslides?   Again, it seems common sense that
if you
>> keep adding more and more stress on the land, that it will give at some
time.
>> Maybe they can approve ten timber harvest plans and the logging roads
that are
>> needed, but what's to say the 11th would not be the one that brings it
all
>> down?   I mean, is the solution no roads?  Or is there no solution?
>>
>> >> Mind you, I'm not against logging.  Not even.  What I am against is
logging
>> >> old growth - leave the elders of all trees alone.  Is it really true
that
>> there
>> >> isn't sufficient second growth, etc. to keep foresters and loggers
working?
>> >
>> >That's probably the wrong question.  The forestry industry has been
losing
>> >workers at a great rate for years.  Oregon lost 12,000 mill jobs at the
>> >height of the Reagan overcut.  In order to be competitive, mills had to
>> >computerize and automate their operations, and the process that started
>> >with the invention of the chainsaw continues.  Sites that are level
enough
>> >are harvested with wood processors that allow one person to do work that
>> >took an entire crew 20 years ago.
>>
>> >The question should probably be, "Is there sufficient second growth for
>> >our needs as a society?"  The answer to that one is "not yet."  While
>> >large industrial forest owners have been reforesting diligently since
>> >about 1920, the State of Oregon didn't start reforesting until 1961,
>> >and the federal government didn't start requiring reforestation of
>> >timber sales until the 1970's.  AFAIK, California got into the act
>> >about the same time the fed did.
>> >
>> >There is some natural reprod on the areas that were harvested before
>> >replanting, but the land is nowhere near as productive as it could have
>> >been with good management.  Second growth on federal lands that is ready
>> >for harvest is often sparse and limby, yielding inferior wood and not
>> >much of it.  The well managed areas are only 20 to 30 years old at most,
>> >and won't be mature for decades yet.
>> >
>> >People who advocate making up the shortfall off of private lands forget
>> >that the US Government owns 2/3 of all land west of the Rocky Mountains,
>> >including  over half of all productive forest land.
>> >
>> >Right now, we are making up the shortfall in supply by importing wood.
>> >Most of it comes from Canada, so we're preserving some American forests
>> >at the expense of a lot of Canadian old growth.  We've also shifted to
>> >new engineered materials, like OSB (Oriented Strand Board) instead of
>> >plywood, because there is no way the current supply of veneer grade logs
>> >could meet the demand, even with imports.  There has also been a shift
>> >to glue-lam beams instead of milled beams, and finger jointed finish
>> >wood, printing press wood paneling, and many other changes to make
>> >inferior materials stretch to do the job.
>> >
>>
>> You're painting a very grim picture for timber workers.  It seems they're
>> f**ked no matter what.
>>
>> Old growth certainly cannot meet society's needs for decades by itself,
and
>> what happens when it's all cut?  IMHO, old growth is old growth, no
matter
>> under whose flag it stands.  Maybe the innovations you describe and other
>> processes yet to be developed will save both the old growth and the
timber
>> workers.  I don't see any other bright spots on future's horizon.
>>
>> >Headwaters is really being cut down by little old ladies in San
Francisco
>> >who want redwood planters for their posies, or suburbanites who want
>> >redwood edging for their flower beds and redwood decks for a patio, or
>> >redwood trim on their hot tub.
>> >
>> 'Tis true.  The fight for Headwaters includes educating the public on
what that
>> flawless redwood trim really represents.
>>
>> >-- Larry
>> >
>> Thanks for taking the time to write, Larry.  :D
>>
>> Camilla
>
>
>





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