Adverse Effects of the C&SF Project — EATING THE EVERGLADES

        To keep our eyes focused on the nature of the problem I've provided an abbreviated version of the many ills brought to the Everglades by the Corps of Engineers through the functioning of the C&SF Project.[1]

        Altered Water Flow Patterns: Today, without the existing water management controls in place, nearly all south Florida would be wetlands. The only exception would be a narrow strip of uplands/pine flatlands along the southeastern and southwestern coastal ridges. Water flow from Lake Okeechobee south through the Everglades to Florida Bay was, prior to modification, nearly continuous. The elaborate system of water management controls now scattered throughout the south Florida landscape has turned what was a natural flow pattern into highly regulated, sporadic, and artificially scheduled releases determined by water levels and user needs. Neither natural rainfall nor ecosystem needs drive the existing management system. As a direct result of human intervention, the entire south Florida region experiences drought in longer periods and higher frequencies.

        Altered Flows to Florida Bay: Decreased freshwater flows from Lake Okeechobee south to Florida Bay have resulted in increased saltwater infusions from surrounding ocean waters, raising coastal salinity to twice its normal level. That sharply increased salinity has damaged and even destroyed fish and wildlife habitat in the Bay. Those reduced freshwater flows are extremely detrimental to the environment and also to the economy as fishing in the Bay has been a major source of livelihood for many south Florida residents and of recreation for thousands of visitors. As a direct result, large areas of sea grass have simply disappeared; the population of pink shrimp, which use the sea grasses as a nursery, has dwindled; and commercial fishermen in the Dry Tortugas, islands west of the Florida Keys where the adult pink shrimp migrate, have seen their catches drop dramatically. The loss of sea grasses, which used to take up nutrients from Bay’s water and sediments, as well as increased amounts of nitrogen from agricultural run-off flowing through the Shark River and Taylor slough into Florida Bay and further south to the Keys, have also contributed to algal blooms. The blooms make the water murky and odoriferous (bad for tourism), robs the water of oxygen, kills coral, and forces fish species to move elsewhere or die (bad for the environment and the economy).

        Overdrainage: Today, 1.7 billion gallons of freshwater are discharged from the Everglades each day, largely from the EAA, so that sugar cane and other crops can be raised, but also from canals in other areas that have been incised into the highly permeable limestone of the shallow aquifer. That constant drainage has in effect diverted water from the Big Cypress Swamp and Everglades National Park through connecting canals, lowering the water table up to four feet, which, in turn, causes increased saltwater intrusion in the coastal aquifers. Which then can no longer be used to provide drinking water. Better start thinking domino effects.

        Soil Depletion: Most of the soils in south Florida were formed under wetland conditions of inundation for most of the year and contain significant amounts of organic material. However, after drainage those soils were exposed to the atmosphere and to an increased availability of oxygen. Decomposition of that organic material occurs at a much faster rate, and the soil surface elevation subsides or is blown away. A conservative estimate of soil loss, especially in the EAA, is one inch per year, or an average of slightly over six feet since 1900. At that rate, in 25 more years in some areas there will be no soil, only exposed bedrock. That enormous soil loss can never be replaced or restored. Never. At least in terms of human history. Nor can those areas be restored as wetlands since the surface elevation has dropped drastically; re-introduction of water at historical levels would produce an enormous lake. Therefore, if agriculture continues for more than 25 years, significant areas within the EAA could turn into a rocky moonscape.

        Nutrient Overloads/Pollution: Agricultural and pastureland runoff from the Kissimmee River passes through Lake Okeechobee and from there slowly meanders to Florida Bay. That runoff, containing high levels of pesticides, nitrogen, and phosphorous from fertilizers and from raw animal wastes, has damaged the entire south Florida ecosystem and has been especially injurious to Lake Okeechobee as the polluted materials accumulate in lake sediments and accelerate the natural eutrophication process. Lake water discharged into the Water Conservation Areas from EAA agricultural lands and pastures to the north and west contains between five and ten times the normal concentration of both phosphorus and nitrogen. When those nutrient overloads enter the Lake or other waterways, the natural system, which traditionally had been adapted to only small amounts of each, became disrupted. Vegetative patterns throughout the Everglades have been altered as exotic species that thrived in high nutrient concentrations drove out native species. Those deleterious effects have gradually but inevitably worked their way downstream into Everglades National Park. In addition, rapidly expanding urbanization from both coasts resulted in the discharge of improperly treated, nutrient- and bacteria-laden sewage into the canal system, causing the canals to be covered with algae, scum, and aquatic weeds, especially in periods of low flow and higher temperatures (summer), resulting in noxious conditions. Surface run-off from the above-mentioned urbanization has also resulted in increased pollution of water in the canals from dissolved-solids and toxic chemicals (hydrocarbons, PCBs, lead, mercury, zinc, etc.).

        Eco-System Disruptions: In combination, all of the above effects of human imposed water management controls have led to drastic alterations of natural, pre-drainage environmental conditions. Across the entire expanse of south Florida, wetland, upland, estuarine, and coastal wildlife habitats either have been severely reduced, altered, or have disappeared entirely owing to severe water flow and water quality modifications. Drainage effects, especially the interruption of the slow overland sheetflow, include the destruction of wetlands, wet and dry prairies, hardwood hammocks, bay heads, pine flatlands, riverine, estuarine, tidal flats and marshes, mangrove swamps, reef systems, and other coastal ecosystems. A widely quoted and representative statistic that serves as a surrogate for the total amount of eco-system destruction that has occurred in south Florida is that between 95 and 98 percent of the wading bird population has disappeared since 1900. Another measure of the level of ecosystem disruption is the sharply increased number (some biologists prefer the word explosion) of exotic plant and animal species that are now common in the Everglades and the Big Cypress. Those invasive species include melaleuca, Brazilian pepper, Old World climbing fern, water lettuce, water hyacinth, Australian pine, bromeliad weevil, feral pigs, black rats, walking catfish, oscar, Mayan cichlid, tilapia, Burmese python, iguana, Nile monitor, and green iguana among well more than 100 major other exotics.

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[1] Some of the text in this section was modified from a web site created by the University of Texas Department of Civil Engineering: “The South Florida Everglades Restoration Project” http://www.ce.utexas.edu/prof/maidment/grad/dugger/GLADES/glades.html#Intro