<<Speaking with a certain simplification, to remove a rapid or rework it, you
<<need a flow in the main river of at least the recurrence interval of the
<<laflood that caused or exacerbated the rapid. 100:100, 1000:1000. Now
<<with the interpolation of the dam, you can't get more than about an annual
<<flood (ca 90000 cfs) from the dam until the full spillways kick in, when
<<the discharge will be 276000.
----------------------
Excellent analysis. With the sediment load of the river cut severely by the
dam, fines will be attacked and the tributary flows will deposit the large
diameter fractions in a way that the dammed river will have difficulty
altering; hence, stair-stepping.
On another subject, I have to scoff at the inflated claims on the "success"
of beach building from the recent "great flood." It may have been a success
regarding funding for badly needed data on various aspects of the Canyon, but
the redistribution of beach sand will, I believe, prove short-lived and only
serve to move beaches downstream from the dam. I have been down the ditch 3
times on private trips since the flood (when it rains, it pours) and it seems
that the new or augmented beaches are eroding rapidly (no pun intended). I
wonder if the beaches in Marble Canyon are diminished with respect to
downstream; if so, the upstream diminishment will be more permanent than the
downstream beaches as long as the dam is present.
Anyway, enjoyed your reply. Have been away from my email for a month, so
sorry if this is an obsolete conversation topic. I am a hydrogeologist by
trade and will remain anonymous at this time.
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