Old Man River . . .

Old Man River - the mighty Mississippi River of course. I learned all I know about the river from my father, a civil engineer and a levee builder par excellence. My father, affectionately known in his retirement years as Paw Paw constantly watched the river. No, he did not go to the levee and look out on the river, he kept up with the river gauge readings at the key locations.

The key locations as far as he was concerned were at Cario, IL; Memphis, TN, Vicksburg, MS; Natchez, MS; Old River Landing in Pointe Coupee Parish, LA; Baton Rouge, LA and New Orleans, LA. Why are those key, well Cairo is where the Ohio meets or joins the Mississippi. It is the beginning of the lower Mississippi valley.

Memphis is the first point below Cairo where the river is constrained. All along the Mississippi are bulges, are wide spots that flood when the river rises. These spots act as sponges soaking up the ever increasing amounts of water flowing south down the river. They are "accumulators" and take the pressure off the levee system. But there is no wide spot at Memphis, all the water passes through a narrow gap with Memphis on a bluff on one side and Arkansas protected by a levee on the other side. So the gauge at Memphis indicates how bad things can get.

The next spot on the river is Vicksburg. It too is on a bluff and the other side is protected by a levee in Louisiana. Once again all the waters of the mighty Mississippi must flow through that gap. The US Army Corps of Engineers has been given the authority to deal with the river and its levees by US Congress. The Corps as it is widely known, divides the upper and lower Mississippi at Vicksburg.

The river is also constrained at Natchez. Again all the water has to pass through that gap on its way to the Gulf of Mexico.

Old River Landing is a spot on the lower Mississippi River Valley where Old Man River was trying to divert itself to the Atchafalaya River. At that point, as the river flows, it is well over 200 miles to the Gulf of Mexico via the Mississippi River and a little less than a 100 miles on the Atchafalaya River. That means the Atchafalaya is a mean swift river that flows down the west side of the Great Atchafalaya swamp past towns like Simmsport, Kortz Springs, Morgan City and so on. All the towns along the Atchafalaya boast of a "ring levee" built after the great 1927 flood. All of those towns have out grown their ring levees and all of those towns fear the great Atchafalaya River.

The Corps has spent billions of dollars at Old River designing and constructing flood control structures to allow some flow off the Mississippi River into the Atchafalaya River. In fact, there is even a hydro electric facility that generates electricity with the drop of some 8 or 10 feet head pressure from the Mississippi River to the Atchafalaya River. There is also a lock to allow barge traffic to go between the rivers and provisions to allow extreme high water from the Mississippi into the Atchafalaya at flood time. This opening would only occur if the Morganza and Bonne Carrie Spillways could not handle the river excesses.

Baton Rouge and south. Baton Rouge is the last bluff on the Mississippi River. The river has never been further east in all geological time, it has been further west often. But the bluff runs out at Baton Rouge, really north Baton Rouge and the old city area. South Baton Rouge, now Louisiana's largest city/parish - 800,000 plus souls, is in the flood plain. Louisiana State University is about where the bluff ends and even part of that is in the flood plain.

New Orleans. Well everybody knows about New Orleans since Katrina. But the gauge watched at New Orleans is the Carrolton Street gauge. The danger points is 18 feet. That's 18 feet above sea level! Yes, New Orleans is protected by levees along the river but they are more or less fixed. When the gauge nears 17 feet or so, the Bonnie Carrie Spillway above New Orleans is opened and water flows in to Lake Pontchartrain and out to the Gulf of Mexico. Lake Pontchartrain is the sixth largest lake in the US and since it is connected to the Gulf of Mexico it is salty. The fishermen and environmentalists have complained for years about the diversion of dirty fresh water out to the Mississippi into the salt lake. Well, it occurs quite often and there has not been any serious damage to the ecology. In fact, geologically, Lake Pontchartrain was created that very way by the Mississippi over times past.

Morganza Spillway starts at Morganza, LA in Poinnte Coupee Parish and flows through the Great Atchafalaya Swamp to the Gulf of Mexico. The spillway parallels the Atchafalaya River to the gulf. It was built in the early 1950s and has guide levees on both sides down into the great swamp area. In its existence it has had two gates opened only a couple of times. I think it has as many 60 or 80 gates. The structure is set back from the river several miles. That area is known as the "forebay" and often fills as the river rises. When the forebay has water in it the Mississippi River at that point is probably six or eight miles wide! That is one of those great accumulators along the river.

The river rises twice a year. It rises in April when the thaw of the Ohio Valley reaches the lower Mississippi River. This year it was a pretty good rise. The Bonnie Carrie Spillway opened when the river reached 17.5 feet on the Carrolton Street gauge. The Morganza Spillway did not open. The forebay did in fact fill up and a couple of high risk farmers lost their soy bean crops.

The second rise is in June. That's when the waters of the Missouri River reach the lower Mississippi Valley. Neither the waters of the Missouri or Ohio by themselves are a threat to the lower Mississippi Valley. That's why a couple of years back St Louis and environs flooded from the Missouri and parts of the upper Mississippi but it was a ho hum thing in the south. That's why today's floods on the upper Mississippi River in Iowa and Missouri and Illinois are going to be ho hum in the south again.

The danger comes when the Ohio thaw is late (and the April rise is late well into May) and the Missouri thaw is early (early like May), them whamo - the lower Mississippi River has too much water in it from end to end.

There are no navigation locks below St. Louis on the Mississippi River and none below probably Louisville, KY on the Ohio (I am not sure about lock locations on the Ohio but there are many). The tow boats require a draft of 9 feet. And even in the years of drought, there is still enough water for most tows to ascend and descend the Mississippi River to St Louis.

The head waters of the Atchafalaya is the Red River flowing out of Texas and Colorado. In recent years, the Corps has made the Red River navigable by installing locks along it in Louisiana. Barge traffic can get to Oklahoma and Texas today at all times. So the Red River is tamed too. Only the Mississippi River is controlled, not tamed through the south. Most of its tributaries along the way are tamed.

It is the lower Mississippi Valley that things can get out of control. The river constantly seeks to change and the levees must be carefully watched at both high and low water. During low water is when repair has to be made. Levees are moved but not in recent times. In my grandfather's day the levee was moved back from its initial location. Our farm faces the river, and we know that some of our land now resides on the bottom of the river. But because we have detailed surveys, we can claim that land for mineral rights - it is still ours.

The levee is granted a right of way. The levee board has absolute control of the levee. But we own the land under it, and on both sides of it. This is why we can graze cattle on the levee. While anybody can drive along the top of the levee, they do not have the right to tresspass on the sides and the bottom areas.

If one looks back at the history of floods one will see that the major problems occurred in Pointe Coupee Parish. It started there and spread all over the place. And that is why my father, a civil engineer, became one of the foremost levee builders along the mighty Mississippi. He grew up there and was a young man that lived through it all. And, yes, he did retire from the US Army Corps of Engineers.

But that is another story at another time. . .