Thursday, May 19, 2011

Rising Tide

Posted by Doug


The words New Orleans and flooding are once again in the same sentence in the national news. The Mississippi River is rising and flooding the Midwest while downriver water is being diverted into spillways to protect Baton Rouge and New Orleans. It seems these diversions are attracting national attention and stirring controversy because there are people and farms in the path of these diversions who will be impacted. I read a response to this story the other day that said, “Let New Orleans flood once and for all and be done with it. Why are we protecting people who live in a bowl?” Why, indeed? The comment barely deserves a reply; nevertheless, I do feel compelled to defend New Orleans.

Human civilization has always sought to live near fresh, clean water. Without water, there is no life. Even with coastal populations, it was more important to be near potable water than to the ocean itself. Water transportation was also the primary means by which people and goods moved long distances before rail, highway, and air travel became feasible. But, for bulk cargo, water is still the preferred route of travel. So, a river that drains 40 percent of the continental United States and empties into a direct route to the rest of the world will have a port at its delta. Industry and commerce will gather at that port and it will be a vital trade and business center for the country and the world. And, let us not forget the natural resources sitting under the floor of the Gulf that feeds the petrochemical industry that nobody else wants in their back yard.

In the south in the 17- and 1800's, the rich farmland along the Mississippi and other major rivers was a huge draw for another reason. Chemical fertilizers were unknown and the richness of the farmland was such that it caused people to take great risks to produce crops with yields and sizes unknown in Europe. The reason for the rich soil was river flooding that deposited new rich silt each spring. But, this flooding meant that a farmer in a flood plain of a major rived could only expect to get a full crop about two out of five years. This set the stage for some poorly thought out decisions.

The government acted to "create" more land and stabilize crop prices through various programs including the building of levees. The US Army Corps of Engineers adopted a levees only policy to manage the Mississippi River. It was a bad idea then and it is a bad idea now. Even the Corp insists that it has abandoned its levees only policy, the current situation standing as evidence to the contrary. Levees crowd the water into a smaller channel raising the river level and creating pressure against the levees. They hugely increase the speed of the flow of the rivers causing tremendous erosion forces. Levees are like drugs – the more you use the more you need. And, perhaps most importantly, levees deprive the flood plain and wetlands of the lifeblood of deposits.

 

Contrary to the common misconception, New Orleans is not below sea level. Like every port city in the world, it is near sea level otherwise it would not make a very good port. The founders of the city settled on the southernmost high land on the river. This land was created by 10,000 years of spring flooding of the Mississippi River. Even as the levees failed during Katrina, downtown New Orleans was high and dry. The French Quarter did not flood any more than during a bad storm. The Garden District was built so that everything could be moved from the ground floor and so that the ground floor was actually designed to be flooded with little damage. Old New Orleans was safe behind a system of levees that were built with state and local money starting in the mid- to late 1700's.



The Corps of Engineers also built the hurricane protection levees that failed to protect New Orleans during Katrina. Once again, the Corp adopted a levees only policy. Then, there is the Mississippi River Gulf Outlet, another blunder by the Corps that acted as a super highway for water to funnel into the shipping channels that serve the Port of New Orleans. For the hurricane protection levees, the Corps used 18th century technology and decided to go cheap and use curtail walls instead of engineered earthen levees. As soon as contractors started building them, they found that the base for the curtain walls in some areas was too sandy and loosely packed to build on. They took their case to federal court to try to get an amendment to bring in hard-pan clay from Mississippi by the thousands of truckloads. The Corps opposed this and the contractors lost and built the curtain walls per spec. They were supposed to withstand a direct hit from a strong Category 3 hurricane. They came nowhere close. The curtain walls collapsed long before being overtopped by Katrina, the soft sands on which they were built heaving from underneath as water piled up against the levees.

For over two hundred years the Corps has been feeding its addition to levees. And, with each levee, the risk of flooding increases. Valuable silt has been shifted from farmlands and wetlands out into the Gulf of Mexico where it only acts as an obstacle to shipping and has to be dredged and pumped further out to sea. The Louisiana wetlands, built up over 10,000 years, that were a valuable resource for fisheries, stopped growing because there was too little silt. Those wetlands are disappearing at an alarming rate. These wetlands also created a natural buffer to hurricanes that is no longer effective. And, soon, they will all be gone.

The Corps' approach to water management on the Mississippi River has been badly informed and driven by an arrogance that its capability was superior to the natural forces it was trying to control. The corps never understood the problems it was trying to solve and was influenced by political and business interests rather than science. Today, many people are paying for those mistakes. The Corp caused the problems we are seeing today on the Mississippi River and it caused the flooding in New Orleans during Katrina. Perhaps now you will understand why, down here, we say, the flooding after Katrina was a man-made disaster.
Jonesville Louisiana, 1973

New Orleans isn’t built in a bowl. It has been and continues to be a thriving port city and a vastly important cultural center. When Katrina struck, mainstream media wondered why anyone would live in a place that could be affected by such a disaster and questioned the value of rebuilding and repopulating the city, even though the damage to the city in the wake of Katrina was largely influenced by poor decisions on the part of the Army Corps of Engineers and not related to local geography. But now that the city is being spared from rising flood waters, mainstream media is again questioning why the city is worth saving. This time the question is why the city, and others like it, should be spared at the expense low income farmers, fishermen, and families living in small communities in the Morganza Spillway. People seem to think that New Orleans should be underwater, but just as this ignored the fact that the levees only policy was one of the most significant contributing factors to the damage caused by Hurricane Katrina, it also ignores the fact that these spillways are designed to direct floodwaters away from communities and guide it into natural flood plains.

The Bonnet Carre spillway is designed to allow the Mississippi to flood into Lake Pontchartrain and the Morganza spillway is designed to allow the Mississippi to flood the Atchafalaya basin. These are areas where the river is naturally inclined to flood in the first place, and areas where the river should be flooding in order to preserve the natural life cycle of the wetlands. This cycle is why the soils in these areas are so rich, and why such a biologically diverse ecosystem evolved there.

The people living in the Atchafalaya basin know that they are living in a flood plain. The Morganza spillway was only opened once in 1973, but it will most assuredly need to be opened in the future. Periodic flooding is the natural cycle of every river in the world, and especially those as large, powerful, and complex as the Mississippi River. On the one hand, it is the flooding of this land that gives it value. The rich soil produces abundant crop yields and the area is teeming with crawfish, shrimp, and crab. On the other hand, the flooding devalues the land because it is expected to flood at some point. This makes the land valuable to farmers and fishermen that take advantage of its bounty, and attractive as cheap property for low income families.

But just because people are living in the Atchafalaya basin does not mean that they are being sacrificed in order to save New Orleans. The residents know that the area will inevitably flood and the Louisiana government only opens the Morganza spillway as a last resort, which is why it has not been opened in more than 40 years. On top of this, the influx of fresh water, silt and nutrients into the area as a result of the flooding will revitalize an ecosystem long denied its natural life cycle. The flooding may adversely impact fisheries this year, for example, but any local fisherman will tell you that this is okay, because in two years there will be a bumper crop.
Bonnet Carre Spillway, 1983

The “Let New Orleans flood” attitude is fueled by misconceptions and misinformation and it ignores the human agency at work in these disasters. In fact, if the government had not acted to control the flow rate ratios of the Mississippi and Atchafalaya rivers at 70% and 30% respectively, these ratios would likely have been reversed due to natural alteration in the course of the Mississippi River. This means that the steeper, faster Atchafalaya River would have become the principle gulf outlet. This would have had disastrous consequences for Louisiana and the entire country; hammering the fisheries, natural gas, and petrochemical industries on which the country relies.

This misinformation is concerning, but not just because we don’t want people to think we’re stupid for living in a bowl. It is important that people understand what is really going on in south Louisiana because human activity is rapidly altering an environment that enabled this culturally, economically, and socially important area of our country to be settled in the first place. If these misconceptions continue to dominate public discourse, New Orleans and the surrounding area very well might not be around in 100 years. There is no doubt that the United States needs the Mississippi River, but like any river system it is a wild and powerful force of nature that cannot be manhandled with brute force. Any means for controlling this river must have respect for, and work in conjunction with its natural forces rather than attempting to bend them entirely to our will.

"The Mississippi River will always have its own way; no engineering skill can persuade it to do otherwise."  - Mark Twain

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