Jacob H. Douma
Well, I'm learning, too--that I've forgotten a lot of things.
You know a heck of a lot more than I'll ever know.
It may come to mind though, if I think for a few minutes.
Miscellaneous Civil Works Projects
Old River Control Structure
Let me ask you about a project you probably know quite well--the Old River Control
Structure on the Mississippi River.
Yes. The Old River Control Structure was built to control the Mississippi River so the
whole river wouldn't go down, what's the name of it.
Atchafalaya, right. I was involved with that project. The control structure consisting of
a diversion channel, spillway, and large gates, was constructed in the right levee of the
Mississippi River to control the amount of water that would discharge into the
Atchafalaya. The district's design was model tested at WES.
One question that arose was whether a stilling basin was needed to prevent excess erosion
downstream of the control structure. After looking at the model, it was decided that a
stilling basin was needed because the Atchafalaya channel banks for some distance
downstream were erodible. Significant erosion in the Atchafalaya could undermine the
whole control structure.
Oh, one further thing. The control structure was located several hundred feet downstream
from the old structure, which was the best location for other than hydraulic design reasons.
This required flow to make almost a
turn from the Mississippi River into the
approach channel. When the flow reached the control structure, the water level was much
higher on the left side of the structure than on the right, if the gates were not operated
uniformly, which probably would cause erosion of the left approach channel banks for
some distance upstream of the control structure. Some concrete and rock bank protection
was provided to prevent that erosion. The sharpness of the
turn at the upstream
end of the approach channel was reduced based on model tests, to improve flow conditions