Water Resources: Hydraulics and Hydrology
Angeles River channel for the last 10 or miles, was not concrete-lined; it was
lined all the way, with drop structures. At the same time, we were designing Santa Fe and
Whittier Narrows Dams.
So the one we see--mostly on TV--is the Los Angeles River?
Yes. That's right. One time someone got the idea that, since the river was dry most of
the time, a traffic freeway should be constructed through the City of Los Angeles on the
bottom of the river channel. [Laughter]
I pointed out that at least small flows occurred at all times along the center of the channel,
so the freeway would need to be placed part way up on the channel banks, with one side
going south and the other side north. The problem was how high up on the banks would
it need to be to remain in service most of the time and not be flooded by river flows
resulting from every rain storm.
Did you get involved in the Santa
River work at all?
Yes, I did.
That's still ongoing, isn't it?
A:
Yes, it is. Prado Dam was built while I was there. I worked on its design. The
hydrology of the whole Santa
River system was reviewed several years ago. It was
concluded that the Prado Dam isn't large enough to take a probable maximum flood. Now
the Corps is thinking about constructing another dam at the upper end of the Santa
River at the base of the mountains.
After Prado Dam was constructed, the Santa
River levees downstream of the dam
were raised so the river channel would carry the Prado Dam spillway design discharge.
However, those levees are not high enough to carry the probable maximum flood
discharge. The levees are so low that if the spillway had gone into its maximum flow, it
would have flooded that development downstream from Prado Dam to the ocean. When
Prado Dam was built there, much of that was just farmland and so on. But now, it's all
houses. The quickest thing they could do was raise the levee all the way down. That
hasn't been completed. The design of the second dam and for additional raising of the
River levees has been completed, but construction has been delayed because of
Santa
budget problems.
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