Jan 23, 2012

"Very good" canyon

I just finished re-reading Down The Great Unknown:

The story of General John Wesley Powell’s Journey of Discovery and Tragedy through the Grand Canyon by author Edward Dolnick.

The Grand Canyon may look the same,
but its hydrograph is night and day different.


By re-read I mean it’s probably the third or fourth time.

Powell himself went down the river twice, the second time of which he didn’t make it full way and, much to the dismay of his crew members the second time around, were not mentioned in his seminal account of his harrowing escapade.  Another interesting fact is that Powell's crew ran the rapids facing backwards.  The "facing the danger" technique of running river rapids had not yet been invented.  Most amazing of all, of course, is that Powell only had one arm.


What would Powell think of the river today?

The book mentions that the run of the Colorado through the Grand Canyon is much the same as it was with the notable exception that its hydrograph has dramatically changed.


Prior to 1960 the river ran free.

It regularly peaked upwards of 80,000 cubic feet per second (cfs) in the late spring only to drop down to a miniscule trickle, often under 7.000 cfs, for the rest of the year.

By modern standards, 2011 was a big flow year.

It marked the first year since the late 1990s 
that water stage in downstream Lake Mead went up.     


Compare that to the river today.

River flow is carefully regulated at upstream Glen Canyon Dam between a narrow range of 7,000 and 40,000 cfs. The seasonal swing from flood to drought is gone.


Do I, like Powell, have aspirations of running the river?

More than likely I’ll just re-read the book (...again)!

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