- Historic Sites
The Bitter Struggle For A National Park
April 1970 | Volume 21, Issue 3
What often happens is eutrophication , the process by which a body of water dies prematurely from lack of dissolved oxygen, choked by a fatal bloom of algae. It is happening all over, and Lake Erie has long been the national prototype. Now scientists are beginning to look at 742-square-mile Okeechobee, the second largest lake wholly within the United States, for signs of the same fatal illness. And they are there. Not far from the inlet of Nubbin Slough, in the northeast corner of the lake, mats of algae grow green and thick in the still water.
“Even without backpumping,” says Frank Nix, a Park Service hydrologist, “there’s already so much fertilizer flowing down from the north that one of these days the entire lake could turn upside down.” The nitrate and phosphate fertilizer stimulates the growth of plant life in the lake. And as old plants die and decay, they rob the water of its oxygen. Then the fish die. Estimates are that Lake Okeechobee is capable of producing fifty million pounds of edible protein annually—channel catfish and bream, mainly, and fish-eating ducks. If the lake should die, so will the fish and the wildlife. And so, at the other end of the pipeline, will the park.
The greatest loss of water in South Florida is caused by evapotranspiration. What comes down must go up, either directly from the heat of the sun or through the cells of green plants. The loss from the lakes of the Kissimee Basin, from Okeechobee and the three conservation districts alone, is estimated to be the equivalent of seven million acre-feet a year. “Why, you wouldn’t believe it,” says Charles M. Wiesenfeld, the corps area engineer at Clewiston. “On a good hot day evaporation takes a quarter inch off the top of Okeechobee. ” With a little figuring, Wiesenfeld estimates that a quarter-inch across the whole, vast face of the lake amounts to 1.5 billion gallons—almost half as much water as the F.C.D. was sending each day into Everglades National Park last June, one of the wettest months in one of the wettest years on record.
Faced with such prodigious losses, the corps and the F.C.D. are now investigating the feasibility of suppressing evaporation with monomolecular, paraffinlike films sprayed across the surface of the water. If even a 10 per cent reduction in evaporative losses could be achieved by such suppressants in Conservation Area 3 the volume of water saved would be more than sufficient to meet the national park’s annual requirement of 315,000 acre-feet. Still, suppressants, like backpumps, could create ecological problems. Preliminary research with some compounds indicates that the monolayers inhibit the emergence of mosquito larvae, which represent a key link in any aquatic food chain.
As the water goes, so goes the peatrich soil of South Florida. That is yet another loss, and it is an irrevocable one. In the days of Hamilton Disston, before the beginning of drainage on a massive scale, the Everglades muck lay fourteen to seventeen feet deep around the south end of Lake Okeechobee, tapering to shallower depths as the land sloped south. Then the canals carried off the water, and the muck was vulnerable—to fire, to wind erosion, to compaction, but most of all to oxidation, a kind of solid-state equivalent of evaporation. In some areas today, up to 40 per cent of the original organic soils is gone. In others, limestone outcrops rise in testament to the farmer’s folly. Even under the best management, which dictates that fields not in production be flooded, the muck is oxidizing at the rate of nearly an inch a year. “They’re not farming that soil,” says Browder of National Audubon. “They’re mining it.”
Physiographic changes no less dramatic are occurring within the park itself and are most visible not in the slope or thickness of soils but in the chameleon character of the park’s plant communities. Aerial photographs taken of the lower Shark River Slough in 1940 and again in 1964, and analyzed by Kolipinski and Higer of the U.S. Geological Survey, show a decrease in wet prairie and saw-grass marsh habitat and an increase in shrub communities. Kolipinski and Higer report two likely causes for this change: shorter periods of inundation and loss of soil through oxidation. These same two forces may also be triggering massive ecological disturbances in the Big Cypress Swamp abutting the park. According to Joel Kuperberg, executive director of the Collier County Conservancy, a significant number of young, shallow-rooted cypress are dying from lack of water. Kuperberg blames the drainage. “The way it’s going,” he says, “we’ll soon have a desert.”
But even Kuperberg, as disheartened as he may be, doubts that a Sahara is inevitable in South Florida. There may yet be time to pull the loose ends together, to answer the questions men are only now learning to ask. There may even be time enough to save Everglades National Park, if the men who could make the right decisions are willing to make them.