"How are Levees Related to River Height?"--Phenomenon Explained Short

[@Sailor376also]

Another excellent description. The one place that you elided over, "Levees protect cities and farmland". That IS the essence of the problem. The farm land should not be protected. No one should live on the flood plain except on stilts or raised paddocks. Allow it to flood the farm land for many miles along the river. Farmers will have their soils renewed without fertilizers,, and yes,, one year in 5 or so planting will be delayed. But,, protect the cities and the levees can be much lower, siltation less. Farm the land, yes, absolutely,, but the flood should cover that farmland wnenever the river needs the space. If this were done all up and down the entire Mississippi and Missouri rivers,, river crests would be lower, fields would be richer. The trick is ALL up and down the river,,,, annnnd you still are going to deal with the occasional 1927 event. What we have now is temporary. It is not sustainable. Just band-aids on top of band-aids, raise the levees again and again, and again. Except New Orleans,,, the higher the levee,, the faster it will sink.

[@lorencklein]

Agree 100% This is just a quick 5-minute video explaining the phenomenon, but I do plan on making it a point in one of the last two videos in the series I'm doing now. Thanks for watching!

[@TBullCajunbreadmaker]

Sedimentation is going to be the exact reason that the Mississippi will be forced to breech it's levees sooner or later. It is just a matter of time before the river changes it's course and be forced to find it's path down the Atchafalaya River channel. We have just not had enough floodwater/sedimentation factor yet. It will happen and it will come about sooner rather than later. I have seen it almost happen in 1973. It was very close and if the river would have stayed at floodstage longer we would be that way now. The waters in Krotz Springs to Port Barre were flowing over the levees when I was driving on top of them and it was very scary.

[@psychogat3]

I'm watching this on the natchez right now haha

[@ballisticsinformation7415]

Being from the pacific northwest I'm very unfamiliar with the Mississippi system but i''m skeptical that levees would cause the riverbed to rise I would expect it to sink do to the concentrated force of the water as has happened to the rivers in my part of the country. I know that most of the Mississippi stream bed has sedmented substantially do to navigation locks preventing course sediment from being carried at low flow. The really interesting thing to consider is that the historic Mississippi stream bed is at equilibrium or how much sediment the river can carry downstream but upstream dams have reduced the Mississippi's sediment load by 50% so if the locks were removed the river would sink by tens of feet into the valley floor. If this could be achieved it would not only greatly reduce flood risk but turn the Mississippi channel into a canyon that could be dammed for massive hydro power generation. The main problem with this is that the locks would have to be removed for decades for the river to incise substantially allowing only seasonal navigation for the immediate gains in flood control and the long term plan of hydro power off the continents largest river.

[@lorencklein]

It's counterintuitive, but the phenomenon is observed in Louisiana south of the Old River Control Structures as well as in other flood gauges on the Mississippi. The levees don't accelerate the river flow enough to promote erosion. This was a theory of flood control in the 1880's through about 1930. Also, unlike the PNW, the gradient is extremely shallow: The Mississippi River drops only 50ish feet of elevation from Old River to the Gulf of Mexico over 300 miles of channel length. Essentially the flood control structures at Old River only remove a portion of the stream flow, and that stream flow has less sediment than what's left over. What continues further south has a higher sediment load, and this continues to settle over time, hence the rising flood heights even though flow rate and levee height remain constant.

[@ballisticsinformation7415]

@@lorencklein Are there any comparable systems without locks?

[@TheSrSunday]

Another nice video. I am looking forward to discuss the river delta engineering with you.

[@lorencklein]

Thanks! I've got two more videos in this series, then I'm moving onto other science topics for a while. However, in my topics to work on one day pile is a dive into the Dutch Delta Works. I've got the books and papers on Amazon Wish Lists and hopefully I'll get to do them.

[@TheSrSunday]

@@lorencklein I daresay the Dutch general works are a bit different from the Mississippi ones, because starting way early in time, having more catastrophes, and less course instability on the part of the Rhin and the Maas.

[@snnetteachexnayder63]

I would ask if the rivers were able to flow in it’s natural way of moving down river and sediment was able to form would that indicate that there would be more land in the rivers path and including the shoreline of the gulf states?

[@adagrow771]

The changes in setting are nice 👌👌👌

[@lorencklein]

We're probably look at these in class this year, and want to do a Vlog-style vibe for these 5 minute videos. We'll see how this all pans out.

[@adagrow771]

Yeah the visual makes it easier to pay attention and is way more engaging I feel like.

[@adagrow771]

Nice grammar by the way

[@carlcarlton764]

3:48 Is she a paddle wheeler? Her moves indicte she has a modern propulsion under her superstructure. BTW, the Great Site says hello!

[@charlesmartel777xx]

Modern propulsion

[@jeffbybee5207]

Should constantly dredgebthe river bottom and dump cuttings over the levee

[@ricardoabh3242]

Good beignets!

[@ricardoabh3242]

Peg Leg Yes! Mmm conspiracy ! lol all fake news I guess lol

[@KieraCameron514]

It sounds like New Orleans should be abandoned.

[@holdens5304]

First