Jacob H. Douma
A:
Yes. It was the first big model of that kind in the United States. There were other smaller
river models, as I mentioned before. Morrough O'Brien had a little outdoor hydraulic
laboratory at the University of California, which he operated to study water level problems
in Oakland Bay.
Q ..
From that experience as a gauge reader, you moved on to be a research assistant in
hydraulic model studies at WES.
A:
Yes. The next job I had was to conduct model studies of
Dam, the first model
of a dam that was built at WES.
Dam was a flood control dam in New Mexico.
It was a concrete dam, about 250 feet high, with an overflow concrete spillway, a stilling
basin, and outlet works.
Since it was the first model of a dam built at WES, we had to learn how to build that kind
of a model, which made it more challenging. After it was constructed, it was operated by
only one engineer. He made all the model flow measurements and wrote the report. That
was really a learning experience.
Do you remember anything that you may have changed in the design of the dam because
of these studies?
A:
Many times changes were made as a result of model tests. For example, with a chute
spillway, high-velocity flow may cause excessive abutment and river bed erosion just
downstream of the chute's end. Then a decision must be made whether a stilling basin or
a flip bucket should be used. If the rock in the downstream river bed isn't suitable to
prevent erosion by the high-velocity flow, then a concrete stilling basin must be used at
the downstream end of the chute to produce a hydraulic jump which dissipates the energy
before it goes into the river.
However, if the rock isn't excessively erodible and the end of the spillway chute isn't close
to the dam, so that the downstream toe of the dam wouldn't be in danger of being eroded,
then a flip bucket could be used. The flip bucket flips the water up in the air, so it lands
a safe distance downstream of the end of the chute and the toe of the dam. The flip bucket
is much less costly than constructing a very expensive stilling basin. That's how changes
are made as a result of model testing.
With
you didn't make any specific changes?
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