> However, to be pedantic, I think they would not exactly have
> lost the Dam, they would have lost the abutment, and there
> would have been a new, S-curve rapid of noble proportion,
> perhaps reminiscent of the old Dark Canyon, which would have
> snaked along the side of Glen Canyon National Dolmen.
Maybe, but Dominy Falls could just as well result. I believe
that Glen Canyon is a combination arch and gravity dam. That
is, the upper part is an arch, which relies on its abutments,
and the lower part is a gravity dam, which stands up because of
its own mass. In any event, the lower part would become a
gravity dam without the upper part. So, if the upper part
failed, it could leave the lower part standing as a significant
obstacle to navigation. It's also possible that the entire
thing could swing out like a door, as Earl describes. No matter
what, part of the dam would certainly fall down. Whether that
consitutes "loss" or not I'll leave as an exercise for the
reader.
There was a completely unsubstantiated rumor in '83 that the
Bureau had a contingency plan to notch the dam, effectively
failing the upper part, if they couldn't stop the erosion of the
abutment and it appeared that failure of the abutment was
imminent. It's believable to me because it would have been
prudent engineering to cause a semi-controlled failure in order
to prevent an uncontrolled failure. (I hope Pierre Salinger
doesn't pick this up.)
Ben
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