I grew up in the low country.
For several thousands of years the Kissimmee River watershed controlled conditions from the edge of the Central Florida Ridge to the Atlantic coastal dunes, and from just south of Orlando to Florida Bay, at the tip of the peninsula. In the rainy season, the area ranged from flooded to partially flooded, wet to damp. Deposition of nutrients by the Summer flood waters provided the nourishment needed for thousands of square miles of verdant growth. The drier areas supported Live Oak and palm forests, along with a vast assortment of smaller palms and undergrowth. Wetter areas were populated with Bay, Sweet Gum, Cypress and other moisture-tolerant vegetation.
The flooded areas were the most productive of all, with pond side and emergent plants such as Cattail, Pickerel Weed, Arrowhead, Spatterdock (a kind of water lily), Sawgrass and other sedges, and huge quantities of grasses and canes. Over decades the low areas would fill with the partially-decayed plant material, and ponds would become marshes, marshes would become wet prairies, in a process called succession. Eventually the upper surface of the soil would become quite dry during the 6-month dry season that stretches roughly from November to March. During the wet Summer season, a vast sheet of water would extend down the peninsula and flow into Florida Bay, where the fresh water and nutrients contributed to one of the richest estuarine areas in the world.
Remember that I said “partially decomposed.” Because the decomposition occurred at the bottom of ponds and swamps, under anaerobic conditions, it was incomplete, and the resulting detritus retained virtually all of its carbon. The fungi and insects that usually complete the destruction of plant material on the surface were absent, and the carbon-rich detritus became compacted into muck, more popularly known throughout the world as peat, one of the earliest organic fuels used by man. Left unexposed to air, peat will eventually becomes compacted by the weight of overlying material. If, in the course of geological time, a few layers of limestone are deposited to further weigh it down, it might eventually become coal or – under different conditions – change over the eons into crude petroleum. This is, in fact, the way all our oil and coal were formed – although oil usually forms beneath heavy, dense deposits of sea salt, laid down when former land areas are flooded by shallow oceans for millions of years – the “salt domes” that are the geological grail of petroleum engineers.
During the dry season (and occasionally during the wet season as well), it is common for lightning to ignite the extremely flammable dry muck. It will then smolder, in the manner of peat everywhere, for periods ranging from days to months. In the old days, the next few rainy seasons would wash away or compact the ash, and a new depression would form, to be filled with water, plants, and to play its part in the cycle.
This process played out ceaselessly, over most of South Florida, for the roughly five thousand years since receding sea levels exposed that part of the peninsula. Pond Apple swamps in the area south of Lake Okeechobee (itself a huge pond, rarely more than 6 feet in depth), created huge muck deposits in that area, as well.
Thus it was until the end of the Nineteenth Century, when developers began “draining the swamp.” First came the ranchers, running enormous herds of cattle over the prairies and piney woods, enhancing them or creating more range by digging drainage ditches and canals. (Florida still boasts Deseret Ranch, the second-largest contiguous cattle ranch in the United States.) This process was aided and abetted by Governor Napoleon Broward and his gang of development (and money) sensitive politicians. Broward gave his name to Broward Couty, ironically one of the counties most devastated – or aided, depending upon your point of view – by the Governor’s unconscionable environmental policies.
Over the first half of the Twentieth Century, a complex system of canals, floodgates, pumps and other water control devices were put into place throughout Florida, especially in the southern part of the peninsula. The net effect of this was to lower the water table by several feet in many places, and to create essentially dry land out of the vast historical wetlands. Nowhere was the effect of this drainage more noticeable than in the mucklands, where agricultural concerns soon discovered and began to exploit the nutritious peat deposits.
Sugar cane plantations covered – and still cover – the former custard apple swamps south and east of Lake Okeechobee. More ranches were developed when the channelization of the Kissimmee River dried out most of the river valley, which was really a wide, shallow depression only a few feet deeper than the surrounding land. This conversion of a meandering, shallow river into a straight, deep canal has caused excessive silting of Lake Okeechobee, and may yet be the death of the second-largest lake entirely within the U.S. The marsh and swamp west of the Atlantic dune region gave way to developments that now house more than four million people, who suck up even more water. Nutrient and fresh water flow across the Everglades to Florida Bay have been reduced and controlled to the point of literally causing the death of once fecund areas of the estuarine system. The source of millions of tons of fish and shrimp is losing its productivity at an alarming rate.
The muck? Well, let me tell you a little more about muck. Recall that it was formed under anaerobic conditions, and retains most of its carbon. In fact, it is the most carbon-rich material commonly found on the Earth’s surface. When it is again exposed to air, it oxidizes -a form of slow chemical burning that releases the carbon to the atmosphere as CO2, leaving the chemical equivalent of a sort of ash – which then washes and blows away with the wind and rain. The muck literally evaporates, never to be replaced, since the conditions that created it no longer exist.
As you can readily imagine, a peat field is not a stable foundation on which to construct anything of appreciable weight. In the muckland, houses were either temporary or built on pilings sunk to the bedrock – perhaps as far as 20 feet below the surface if the muck deposit was especially deep. These houses have remained intact in many areas, especially near the south end of Lake Okeechobee. They no longer rest just above the ground, as they did when first set upon their pilings, but are as much as eight or ten feet above ground level now, access secured by flights of steps built longer and longer as the ground subsided due to oxidation and erosion. Keep in mind that these houses were supported by the rock beneath the peat, not by the peat itself.
I know a little bit about what happens when you muck around with nature.
Now let us jump to the Mississippi River Delta several hundred miles to the northwest, another of the formerly great estuarine systems. The towns and cities of the Delta – most notably New Orleans – were build on similar foundations. The original settlement that became the Big Easy was constructed on the bank of one of the principal channels of the river, several feet above the high tide line. Over the years, as dikes were built and buildings added, the land subsided as the ground dried and compacted, similarly to that near Lake Okeechobee, but with differences.
First of all, the depth of the sediment in the Delta is many times greater than of the muck in South Florida. Although it does not oxidize as much, it does compact under weight, so much so that adding five feet to a dike in the New Orleans area causes the dike to sink two feet, for a net gain of three feet over time, rather than five. By the time of Hurricane Katrina in 2005, the city had subsided so much that you could walk along the ship channel at street level and look up at the ships on the river. Large buildings can be constructed with footings down to the underlying rock, which stops compaction at those points; streets and homes, however, are a different matter. Their weight, along with, parking lots, moderate-sized buildings such as shopping centers, schools and so forth all cause the ground to subside further.
In addition, the wetlands to the south of the New Orleans/Lake Ponchartrain area have been reduced by about 2,500 square miles during the past century, as increasing channelization of the Mississippi removed the flow of sediment that nourished the Delta for millions of years. The ship channel is now diked and dredged far into the Gulf of Mexico, effectively cutting off water flow to the areas east and west of the main channel. Those wetlands, New Orleans greatest protection against storm surge, have subsided as well, the land loss exacerbated by erosion caused by hundreds of canals that drained the southern part of the Delta to facilitate oil exploration, shipping, and pipeline construction. The channelization has also resulted in changes to the area hydrology that effectively funnel water directly into the New Oleans urban area when storm winds come from the south or southeast – the most powerful winds in a hurricane.
All of the above, taken in context, give us an idea of what would be necessary to “rebuild” NOLA. Just as the restoration of the South Florida hydrology would be economically incredible, so would the restoration of the Delta, and complete restoration – or at least rearrangement – would be necessary to avoid another Katrina-like catastrophe. At a bare minimum, it would be necessary to
- refill the New Orleans basin to raise the surface nearer sea level (where would the fill come from?);
- redesign the hydrology to keep storm surge from the city, including restoration of the buffering wetlands to the south and southeast;
- build higher (and also deeper) dikes, in a manner that would prevent over topping and erosion inside and beneath the dike structure (recall that this was supposedly accomplished the first time, but proved not to have worked out well);
- Pay for what would be the largest engineering project in human history.
Successful restoration would also necessitate redesign of the shipping channels to funnel sediment back to the presently deprived Delta regions. During the years necessary to rebuild those areas with natural sediment flow, there would still be a lack of protection from storm surges. It must also be kept in mind that, until these engineering feats are completed, a matter of decades, the area would be vulnerable to storms that could set the entire project back to zero at any point in the process, and we haven’t even mentioned the inevitable rise in sea level over the next century or so, or considered its effect on all these undertakings.
Measure all this against the cost of redirecting shipping and rail heads to other Gulf Coast ports, essentially returning the Delta to nature, and decide what is feasible economically – not emotionally, but economically. Do we put the nation in hock (even worse than the Bush Administration has already) for gains that could be lost during any hurricane season, or do we tighten our belts, keep a stiff upper lip, and pursue a more reasonable course? I’ll be retiring in a few years. You’re not taking the money out of my retirement income – not if I have anything to say about it – and I don’t think my granddaughter and her kids should have to pay for it, either. They’ll have other problems to solve.
Tell you what. If they decide to rebuild New Orleans, I want them to rebuild South Florida, too. It would be a lot cheaper and it’s likely to last longer, even allowing for the rising sea levels that will eventually force the abandonment of most of that coastal area as well.
Folks, it’s time for us Americans to learn the difference between wants and needs. It’s really, really time.