Heavy rains, poor maintenance, and a hurricane’s storm surge can quickly break a levee, resulting in the devastating but preventable Mississippi River floods. The floods occur when levees – the protective earthen embankment – within that system are topped, overtopped, or breached. The Mississippi River is mainly held back with levees, which are lined with pumped-out water, with locks to help keep ships from colliding and to help keep them in the correct direction. This has not always been the case though, in the past one of the most common causes of flooding was heavy flooding or overtopping of the levees.
The Mississippi River levee system is split into several sectors, the most severe flooding occurs on the Lower Mississippi section, stretching from the states Louisiana to Mississippi. Since the start of the 20th century, due to a combination of increasingly strong storms and lessened concern over the weak levees, the number of floods of this region have increased dramatically.
In the summer of 1927, a widespread flood of the Lower Mississippi River occurred. With the worst damage occurring in Arkansas, Louisiana, Mississippi, and parts of Tennessee. By the time the floodwaters receded in early fall more than 23,000 square miles were submerged, 27,000 people homeless, and about 500 were drowned.
Since then, Mississippi River levees have flooded many times and those in Arkansas and Louisiana generally faced higher damage due to the impact of winds from hurricanes and their storm surge on the fragile barrier islands in the Gulf of Mexico that block off the main stem of the Mississippi. In 1993, after flooding for 68 of 72 days and overpassing the levee, water reached 54.7 feet in Vicksburg, MS due to Tropical Storm Alberto.
A 2005 Hurricane Katrina surge was six feet high and took out sections of the levee. Almost 80 percent of New Orleans flooded, and seven states were declared federal disaster areas. About 1,800 people died and 1.5 million displaced. That levee break caused $21 billion in private property damage, according to FEMA.
In 2011 near New Madrid, MO, the levees broke after heavy rains. The destruction of river ports between Memphis,TN and Cairo, IL reached 8 million dollars. The destruction was mainly occurred in agricultural land, as well as homes and businesses located near the levees. Additionally, the flooding damaged roads, bridges, and levees.
After all these floods,no levee Flood Control System is completely infallible. That is why it is important to build an integrated flood risk management, in which the floods are managed from multiple perspectives such as engineering, economic, socio-environmental, and legal. Experts agree that there may never be a way to completely prevent floods, and that investments must be invested in areas where works have been proposed but have not been implemented, such as improved levee monitoring and high-risk emergency management plans.
The Costs
The cost of a failure in the Mississippi levees can be quite expensive. In the event of a flood, the damage can increase exponentially because of the need to repair the levees. If the floodwaters break through the levee, the entire area can be inundated with water, usually hundreds of miles upstream or downstream. Furthermore, the economic costs of flooding often doesn’t take into account the cost of lost lives and displaced people, nor does it take into account the environmental cost of pollution and habitat destruction caused by flooding.
The 2018 National Flood Insurance Program (NFIP) reauthorization requires the exploration of new, untested methods and technologies like levee repair and modernisation that could lead to further improvements in levee safety and flood prevention. However, according to the National Flood Program officials, the continuous maintenance and repair of levees can be costly. Both local and federal governments are responsible for maintaining the levee system, although the localities receive much less assistance from the federal government in terms of maintenance and upgrades.
The average cost of a single levee break could be in the millions, although it can vary significantly depending on the size of the area, level of flooding, and time spent at high water levels. A study by the United States Army Corps of Engineers accessed the damages of flooding in the Lower Mississippi watershed. The estimated damages of the 1997 flooding on the Little River in Arkansas alone was a total of $135 million.
Effectiveness Of Levees
The strength of levees depends on the type and amount of material used to construct them, and how much maintenance is done on them. Levee systems that are built hastily with cheap materials can quickly break down and lead to flooding. This is what happened with the levees in New Orleans in 2005, when Hurricane Katrina stormed through the area and caused them to fail.
The US Army Corps of Engineers continues to assist with the long-term planning and maintenance of the levee systems across the Mississippi River. Technologies used in the levee system include traditional methods such as reinforced concrete, sheet-pile constructions, and sheet piling; as well as modern techniques such as gabion wall systems, hydraulic siliconised sandbags, and expandable geotextiles. The Corps also tests the levees on a regular basis to check for any weaknesses or potential breaks.
Lower Mississippi levees are also upgraded with more modern materials and advanced construction methods on a regular basis. Many of the local governments in the region have also been pushing for stronger and higher levees. However, due to the limited financial resources available and the complexity of the projects, this hasn’t always been as successful as it could be.
Operations & Maintenance Of Levees
Levee operations and maintenance are important to keep them in the best condition to protect communities, save lives, and protect infrastructure. Maintaining levees on the Mississippi River is no easy task, as its incredibly long 8,100 miles meander through 10 US states, passing locks and dams, harbors and tributaries, as well as various cities along the way. Since the Mississippi River is the primary source of water for Louisiana and Mississippi, operations and maintenance of the levees is often essential to keep the river on course.
The US Army Corps of Engineers provides regular maintenance for the Mississippi River levees and inspects them for any potential problems or damages. Failing to keep the levees in good condition can lead to costly damages, as was the case with the near catastrophic flooding in 2005. The Corps also takes an active role in monitoring the levees and warning communities downstream in case of danger, as well as helping to coordinate emergency preparations in the event of a possible levee breach.
Aside from regular maintenance, the levees are also monitored for signs of problems or weaknesses. Several technologies are used in the monitoring systems, including pressure sensors, radar, and aerial cameras. These technologies can detect even the slightest signs of a potential breach, such as bending, seepage, or erosion, and help the Corps to determine the best course of action to prevent further flooding.
Conclusion:
The Mississippi River levee system is responsible for helping to prevent flooding of thousands of square miles in the US states of Louisiana and Mississippi. The system is vital to the local economies and to the safety of homes and businesses within the region. Its importance is evident in the large number of floods that have occurred over the years, which could have been prevented had the levee system been in good working order. Regular maintenance is essential to keep the levees in the best condition to protect communities, save lives, and protect infrastructure.
