Nature Walk Brings Thoughts Of Climate Variability

Trekking through the Couturie Forest in New Orleans’ City Park on a quick nature walk, I find that fog limits visibility, and mist hides the birds I can

hear. Only a few less-exciting species are visible, though I catch the call of a red-shouldered hawk. I ventured into a part of the forest I had not been in many years. The walk was about decompressing. Nature is my sanctuary from the stresses of my professional river life, dredging obstacles, not sediment. The ability to embrace the serenity of nature is a chance to mentally reboot and to recharge my circuits by looking for snakes, flowers, exotic birds and alligators.

The pulse of nature that day was lax and calm with the cover of the liquid air. I decided to go uphill and leave the sides of the bayou to climb a mountain. The highest elevation in Orleans Parish is within the Couturie Forest, and, braving it without gear, a free climb of a daunting 27 feet above sea level without oxygen or ropes is downright exhilarating. Few will know that there is indeed a geographic feature ironically named Laborde Mountain in this stretch of forest. As I approached the peak, I noticed something I did not remember from my childhood walks of decades ago.

There in the mist was a forgotten circular concrete platform on the top of the mountain. I promptly recognized the familiar shape of a replica map of the crescent shape of the New Orleans riverfront — the Crescent City. A concrete slab featured a map of the sharp bend at Algiers Point of the Big River. The river impacts all phases of life here and is in my DNA. The significance also dawned on me later that, on this date one decade earlier, I was at the earliest opening of the Bonnet Carré Spillway ever — January 10, 2016. Little did I know the opening of the Bonnet Carré that January would kick off a decade of unprecedented river stage response events.

Since 2016, the Bonnet Carré has been operated more times than in any other 10-year period by far. In fact, prior to 2016, the need to operate this critical floodway had averaged once a decade. Related to the term, I use “climate variability,” which means long-standing metrics and averages no longer hold true.

I use this term that was a lesson by a mentor, longtime Senior U.S. Army Corps of Engineers leader now retired, Mr. Eddie Belk. He first coined it, and I have adapted or expanded upon it. Leaders like Mr. Belk are inspirational by nature.

There is no such thing as an “average river” anymore. This decade started off with high water and plenty of it. Bonnet Carré level high rivers seemed to be the newest trend, with weather science indicating the need for getting used to it as precipitation around the world has been increasing the last 100 years. High rivers are a sign of the future, and increased precipitation is expected to continue.

This was easy to believe when the river levels required the operation of the Bonnet Carré in 2018, but hold on, not only was the operation of this critical flood control structure required in back-to-back years, with an opening required from February 27, 2019, to April 11, 2019. It was followed with the unimaginable opening twice in the same year when the structure was again operated from May 10, 2019, to July 27, 2019.

Few realize that the 2019 flood was far and away the largest volume of water to flow down the Big River in U.S. history, with trillions of gallons more than the Great Flood of 1927 and the flood of 1973. Then, in 2020, we had another high river, so the hydrometeorology crowd seemed to be spot on.

The 1970s were a wet decade with three openings of the spillway (1973, 1975 and 1979), but the operation was not required at all in the 1960s, and there was a 14-year span between the opening in 1983 and 1997. Climatologists told us then that we should expect more high rivers. After this incredible period with five openings of the flood control structure in five years, we believed them.

However, since 2022, we have seen a record period of drought. The term unprecedented loses its meaning if it is used repeatedly. It’s the same for average or normal. Neither fits this last decade of extreme weather events generated by “climate variability.”

Flash to Newton’s Third Law (Law of Action-Reaction), which states, “For every action, there is an equal and opposite reaction.” It’s scary to see this reality in Big River stage swings, but this last decade has been the most challenging for deltaic riverine management and navigation in the maritime history on the Big River. The occurrence of such dramatic variance from high to low river stages in multiple year patterns has never been seen before and is truly remarkable.

Low river stages in the fall of 2022 led to the construction of the saltwater sill, a barrier that is in essence an underwater levee constructed on the river’s bottom to thwart the upriver migration of the toe of the saltwater wedge and prevent it from reaching the freshwater intakes for the city of New Orleans. The sill is constructed about 12 miles downriver from drinking water intakes in Belle Chasse, just downriver of New Orleans. In river terms, that’s not necessarily south as in a cardinal direction, as it is along the serpentine bends.

The longstanding average prior to 2022 for the construction of the saltwater barrier had also been once a decade, just like the spillway. The last time the sill was constructed was a decade earlier in 2012. In fact, due to the gap in time, few were aware of the impacts of low river stages or the impact constructing the saltwater sill creates for commercial navigation. Over the next four years this changed, including a revolutionary adjustment required in 2023.

On October 11, 2022, the Corps, through Weeks Marine, began the construction of the saltwater control levee, also known as the saltwater sill. The year 2023 followed the same pattern as 2022, and the sill’s construction went from once a decade to twice in two years and then twice in the same year.

The Big River Coalition was tasked with providing information on the number of vessels that would be impacted if the entire sill was raised to 30 feet below the waterline by the Corps of Engineers. The number of vessels impacted was staggering and led the Corps and Weeks Marine to adapt, leading to a new concept, an augmented sill with a revolutionary design.

The sill augmentation kept commerce moving and was constructed with a “navigation notch” at -55 feet and the rest of the sill at -30 feet. It performed extremely well. It repelled the saltwater wedge and kept ship traffic moving. The commercial damage of a draft restriction of 30 feet would have been tremendous and had long-lasting implications.

Then, not to be outdone, low river stages continued in 2024 and 2025, requiring the construction of the saltwater levee. Unprecedented? Well, last year during 2025 another first almost occurred: the operation of the Bonnet Carré, and the construction of the saltwater sill, in the same year. It was close to happening last year and is likely to happen with more extreme events forecast to occur soon, unprecedentedly indeed.

The high river stage on May 1, 2025, was higher than previous years when the flood control structure was operated, but the stage forecasts showed a quick spike and rapid fall. The Corps is clearly more focused on the negative impacts to the environment in Lake Pontchartrain and the Mississippi Sound.

There remains ambiguity in long-range forecasting of river stages. The message in 2019 was to expect more high-river events and to get used to them. The message in 2025 was to expect more variability between extreme stages. The 2025 Greater Mississippi Trends report, a requested update to the 2019 effort, said that all types of precipitation have increased in recent years, along with extreme weather variances from what had been expected in the past.

As spring of 2026 gives way to summer, there is still a mountain to climb. Being on watch and monitoring climate variability’s effect requires diligent monitoring and preparation both to keep the nation’s economy afloat on the Big River and to protect the environment and drinking water of New Orleans.