By Gerard Braud –
As we remember Hurricane Katrina 10 years ago, there needs to be strong communication from experts about how natural defenses, such as coastal marshes, can avert a crisis, such as hurricane flooding. Coastal marshes have been disappearing at an alarming rate of 33 football fields a day for decades. How does this affect you? Read on…
Existing erosion is a story that needs to be told before too much attention is shifted to other environmental issues, which is the rise of sea level. The Weather Channel is showing a program focused on a Hurricane Katrina impact in 2065, based on projected sea level rise. President Obama is also expected to focus on how climate change will affect coastal regions when he visits New Orleans during this anniversary week.
But a greater, unaddressed concern for me is the fact that tidal surge in every hurricane can be reduced by healthy coastal wetlands today. However, the coastal wetlands near New Orleans have been eroding away since levees were first were built along the Mississippi River in the 1930s. Those disappearing wetlands take away nature’s natural line of defense, which is why they need to be restored.
In a 1995 documentary I wrote the words, “Every day Louisiana loses 33 football fields of land, an inch here and an inch there.”
The documentary was called Reversing the Tide, but little has happened in the 20 years since then, except a few pilot projects, more studies, and more talk. A master plan has been created, but too much time is passing without real action.
Scientists say that roughly three miles of healthy, vegetated wetlands can reduce a storm surge by one foot. In some studies based on actual storms, a single mile of wetlands reduced storm surge by one foot. Ironically, one of the major studies on wetland benefits was done by the U.S. Army Corps of Engineers, which has been in charge of building major flood walls around New Orleans, without building major wetlands in front of those walls.
Just outside of those billion dollar concrete walls built since Hurricane Katrina is now water, that just a few decades ago was land. Based on interviews I’ve done with experts over the past 30 years, my belief is a sizeable chunk of money should have been used to rebuild coastal marshes and natural defenses, rather than only on modern engineering marvels that will be topped again by a hurricane’s storm surge.
As constructed now, these walls are the equivalent of placing them on a seashore against violent waves. But if sediment from the Mississippi River is pumped into the marshes to rebuild vegetated wetlands, sixty miles of wetlands, in theory, it would reduce a twenty foot tidal surge to only a few feet of sea level rise. This would put low water levels and waves lapping against these walls rather than the force of a major ocean at maximum fury. And as sea levels rise from climate change, the rebuilding of wetlands can be a sustainable effort.
I’ve spent untold hours in these coastal areas with fishermen, scientists, environmental activist, and engineers. Decades have passed with the various parties at odds. Environmentalists worry about pollutants in the sediments from the Mississippi River. Fishermen worry about losing money as their current fishing waters turns back into land, as it was 50 years ago. Scientists and engineers fight about the best way to tackle the task, often resulting in little or no action. Politicians, who should be funding the projects, are blind to the fact that money spent today in the right way, is a better bet than paying for the massive clean up and restoration of communities, as seen in Hurricane Katrina.
Here are the realities as I see them.
- Human engineering created the problem when citizens and politicians asked for levees to be built along the Mississippi River after the great flood of 1927. Marshes are naturally created over thousands of years as annual spring flooding deposits silt and nutrients into the wetlands. The wetlands provide natural storm protection and a healthy ecosystem for fish, birds and wildlife. These marshes are also a natural filtration system that removes pollutants from our earth. Restoring the marshes and reversing the tide must be a priority.
- In a modern economy, money mitigates opposition. Commercial fishing is a major part of the economy in this region. Fishermen today, catch fish in areas that consisted of land just a few years ago. This region is a delicate ecosystem with a precarious blend of fresh, salt, and brackish water. The balance has been upset for 50 years. Reversing the trend and the tide, by rebuilding land, will cause a temporary balance change. It can restore a traditional balance and create long-term benefit, but only after a short-term upset. To do this, fishermen will need the same type of financial support congress grants to a farmer who loses his or her crops because of a drought. Pay it, be done with it, and move on with fixing a problem.
- The Mississippi River is constantly being dredged to keep navigation channels open for shipping. For decades, the silt has been dumped in the deep waters of the Gulf of Mexico. I’ve watched test projects done in which the dredged sand is piped over the river levees and into the eroding wetland. This process can build hundreds of acres of land in just a few days. It is the fastest and lowest cost way to restore the land that has eroded away. The negative impacts on the environment, the fisheries, and the fishermen are far outweighed by the positive impact it will eventually have on the environment, the fisheries, the fishermen, and natural hurricane protection.
The greatest harm comes when humans get in nature’s way. The greatest benefit would be to give nature a helping hand to heal the wounds that we have helped create.