Water Resources: Hydraulics and Hydrology
Q ..
Keep the sediment in the channel?
A:
Right.
Q.
So your objective, mostly, is to keep the sediment moving.
A:
Right.
Dams
And to keep increasing the speed of the flow?
Navigation dams are very low structures. The spillway sill is almost on the river bed. When
the spillway gates are fully open, then the dam is a very small obstruction so whatever
sediment comes in the upper pool, hopefully, goes through. It doesn't quite work like that,
but that is the objective.
They're a totally different creature from a high dam.
A:
From a high dam, yes. I understand that on the Upper Mississippi where navigation pools
are about thirty miles or so long, essentially the whole pool has filled with sediment and there
is now a relatively narrow channel at normal pool level that navigation follows. I think they
have been trying to flush some of sediment through the pools, but I really don't know what's
going on at this time.
Yes, because some of those dams go back a number of years.
Yes, back to the `30's.
A:
The main ones on the nine-foot channel, I think, are the `30's.
Yes.
A:
So what kind of problems do you face--you're talking about silting in. There's a point in
tirne where these things are going to silt in almost completely..
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