On saving the Big Cypress and the green swamps of Florida - May 14th, 1973

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On saving the Big Cypress and the green swamps of Florida - May 14th, 1973

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On saving the Big Cypress and the green swamps of Florida - May 14th, 1973
Parker, Garald G. (Garald Gordon)
Publication Date:
Physical Location:
Box 2


Subjects / Keywords:
Aquifers -- Hydrogeology -- Everglades (Fla.) ( lcsh )
Hydrology -- Florida -- Biscayne Aquifer (Fla.) ( lcsh )
Big Cypress National Preserve (Fla.) ( lcsh )

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Source Institution:
University of South Florida
Holding Location:
University of South Florida
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The University of South Florida Libraries believes that the Item is in the Public Domain under the laws of the United States, but a determination was not made as to its copyright status under the copyright laws of other countries. The Item may not be in the Public Domain under the laws of other countries.
Resource Identifier:
032968560 ( ALEPH )
891343127 ( OCLC )
G16-00697 ( USFLDC DOI )
g16.697 ( USFLDC Handle )

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FROM THE DESK OF,THE CHIEF HYDROLOGIST: By On Saving The Big Cypress and The Green Swamps of Florida Garald G. Parker, C.P.G. !/ Almost everyone in the United States has heard of the Big Cypress Swamp. This huge area of chiefly stunted cypress forests, marshes and wet prairies, isolated "pine islands'' an~ stream courses lined with tropical forest vegetation, tall old cypress trees and, in places, royal palms, covers nearly 2,450 square miles mostly in Collier County immediately north of the Everglades National Park. Its center lies about 70 miles northwest of Miami and within its sou_theastern boundary, just north of the Tamiami Trail and adjacent to the Everglades' western boundary, _the Miami International Jetport was begun in 1968. !twas the jetport that focused both national and international attention on the Big Cypress Swamp as the forces of conservation led the fight to stop t~e jetport and finally, by 1970, marshalled enough force to get it stopped. The arguments were not so much the jetport of itself, but of concern over the pro-. . bability of drainage lowering water levels and ~estroying the local ecologic • balance, plus the noise of the jet engines frightening birds and mannnals away from the site for miles around. The principal fears were those associated with expected economic and social pressures creating a large growth of further land development in the area surrounding the jetport. Such land developments for housing, trade and jetport-associated industry would probably have led to largescale land drainage outside the jetport propertye Human, agricultural and industrial wastes would have been expected to bring about eutrophication of the drainage waters that, in large measure, the Everglades National Park's flora and fauna depend . upon _ . Y Chief Hydrologist and Senior Scientist, Southwest Florida Water Management District, Brooksville, Flori~a.


I Speaking of water and water supply from the Big Cypress Swamp, Edward T. La Roe, biologist and executive director of. the C.Ollier County .Conservancy District is.quoted by the Tampa Tribune (05-12-73, p. 1-E) as saying that the benefits of Big Cypress all relate to one thing --water. "Water is the key to the importance and value of the Big Cypress and 'is the key to its vulnerability, too. The Big _Cypress Swamp acts ~s a great reservoir --the last undisturbed one in South Fiorida. It collects and slowly releases to the coastal areas of southwest Florida a vast amount of unpolluted fresh watero" As th~ situation now stands, support of both state and _federal governments have been won to purchase much of the Big Cypress Swamp. Senator Edward Gurney on 05-10-73 asked a Senate Appropriations Subcommittee to budget $130 million to help complete acquisition of the endangered lands of the Big Cypress. The State.of Florida has already put up $40 million. This.purchase is designed to . keep the swamp out of the hands of the land-developers who, in order to build their trailer parks, ' 'new cities" and commercial establishments, would have to drain the wetlands with ditches and canals, pave over large parts of the aquifer recharge area, and cut down and thus destroy the natural beauty of the swamplands~ The greatest danger of all, of course, is the drainage and possible destruction of the fresh-water recharge potential of this huge watershed. It is to prevent this threat to the water resources and to the environment that President Nixon early this ye_ar, asked the. Congress to purchase nearly 855 square miles of the Big Cypress. Secretary of the Interior M:>rton has estimated that this will cost considerably in excess of $100 million with the purchases to be spread out over the next ten years. Just how much water does the Big Cypress Swamp produce in runoff to the Everglades National Park? The U. s. Geological Survey calcula~es that its average annual discharge (runoff) into the Park is 541, _510 million acre-feet per year, -2-


or about 176.5 b~llion gallons, which is about 480 million gallons a day. This is only about 4.24 inches or 8 percent of the total of 53 inches of precipitation that the Big Cypress receives annually. The rest of the 53 inches, subtracting .runoff of 4.24 inches, is 48.76 inches which is mostly lost to evapotranspiration. Some unknown but relatively minor part of this 48.76 inches becomes ground-water recharge and serves the southwestern coastal towns and villages of Naples, East Naples, Marco, Copeland, Everglades City and Ochopee, plus scattered homes and service stations along the Tamiami Trail (US 41). Thus the Big Cypress Swamp cannot be counted upon to serve a large, growing population in southwestern Florida. Its current water crop potential is practically all used up by demands of the Everglades National Park with only a small excess left for growing urban development. None-the-less the Big Cypress is well worth costs of its saving, if only to assure the perpetuation of this small water crop --less than 50_(),000,000 gallons per day. -It is this flow that assures the survival of much of the Everglades National Park, a national heritage we should, at all odds, protect for all time. The Green Swamp, as contrasted with the Big Cypress, has not made the • national and international press. Neither has it excited much comment in the statewide press. None-the-less, the two swamps have much in connnon, the main differences being that: (.!) the Green Swamp does not maintain the water supp}y of a major national park; and (2) ~, together with the surroundfng high lands which comprise the Green Swamp High, serves about 90 percent of the water-supply :: -demand of more than 1~5 million people in central Florida. This is an area of extremely rapidly growing urbanization largely sparked by the Disney World development, and population _of the area is expected to more than double by 1985 • . In most physical and hydrological aspects the two swamps are much alike though the Green Swamp proper is much smaller and stands much higher above sea -3--


level than the B~g Cypress. Both receive an average of 53 i~ches of rainfall and both suffer high evapotranspiration losses though those of the Big (fypress are considerably larger than those of tqe Green Swamp. The Green Swamp proper, covering about 870 square miles, is not a typical swamp at all but is a high, flattish, poorly drained plateau sloping to the west and northwest. It lies mostly in Polk and Lake Counties with smaller parts in Sumter, Pasco and Hernando Counties. Its eastern margin stands about. 200 feet above mean sea level from whi~h -it slopes gently to an elevation of about 75 feet on the west where it drains to the Withlacoochee and Hillsborough Rivers. Actually, drainage of the swamp is poor. and sluggish, thus giving rise to large stands of such water-loving trees as willows, cypress, gum and bay, .generally more or less aligned along the shallow drainage courses. Large areas of wet prairie occur on its poorly drained soils whereas scattered "islands" of pinelarid occur on the slightly higher~ better-drained lands; and during rainy seasons most of the Green Swamp is covered by water from a few inches up to ~en or more feet deep. Thus, the Green Swamp is really a high, poorly drained upland with only patches and strands of true swamp • scattered widely over it. Generally speaking, most of its area is unsuited for homes or business establishments and would best be preserved as parklands, greenbelts~ water conservation and flood-detention areas, wild-life preserves and as partial sourc_ e of water supply for the burgeoning population of central Florida. The land surface is comprised, for the most part, of permeable sand, thinnest in the west where the solution-riddled limestones of the underlying Floridan Aquifer are at or only slightly below the surface, to a hundred or more feet deep in the east. The Floridan Aquifer underlies the entire State of Florida but reaches its highest elevations south of Ocala here in the Green Swamp and from the highest point not only does the surface drainage begin but so does the ground-water flow. -4-~-............ .,... . .,..-_.......,.. _


Five major rivers originate here. At the u. s. Geological Survey streamgaging stations located closest to the outer boundaries of the Green Swamp proper, the streams and their averag e annual flows are: Withlacoochee .River at Croom, 541 mgd (million gallons a day) which is a runoff equivalent of 8.09 in/yr (inches a year); Hillsborough River near Zephy~hills, 188 mgd = 17.44 in/yr; Peace River at Bartow, 190 mgd = 13071-in/yr; Oklawaha River at M:>ss Bluff, 240 mgd = 5.52 in/yr; and Kissimmee River near Lake Wales, 747 mgd = 9,70 in/yr • . Thus, total annual runoff is about 1,706 mgd or more than 3.5 times the runoff. (potential water supply.that might be derived from streamflow) of the Big Cypress. But these streams are less sources of water supply than they are so1:1rces of flood-control problems. Nodeep valleys are present anywhere in the area in which large and economical water-supply reservoirs can be constructed and into which the annual flood flows could be stored. The huge Floridan Aquifer acquires much of its recharge over the more than 2,900 square miles of the . Green Swamp High, and it is the ground water from the .Floridan Aquifer that supplies more than 90% of all water supplies .utilized in peninsular Florida. The Green Swamp High is one or three major recharge areas in pertinsu1ar Florida; the other two are the Pasco High, of about 685 square miles, which centers in Pasco County about 40 miles due west of the Green Swamp and the Putnam Hall High, of about 1,020 square miles, which centers about. 110 miles north of the Green Swamp. The Pasco. High furnishes most of the water supply to the coastal area from Tampa (including about one-half _of Tampa's supply) north to and beyond Weeki Wachee. The Putnam Hall High serves a vast area including part of Suwannee Basin, part of the Silver Springs Basin, part of the Rainbow Springs Basin, and much of the Upper St. Johns Basin. The Green Swamp High, together with its surrounding recharge areas to the north and northwest, serves an even larger area, including in part the Upper St. Johns Basin, the Peace River Basin, and -5-


the coastal c1rea fro. m Charlotte County north to Tampa. Although the Green Swamp High is thus not the only recharge area in Central and South Florida, it is one _of the three most important and likewise up to now one of the least developed. It is essential to protect it from the "ditchers," "drainers," and "developers," who could ruin it as a source of water for the rapidly urbanizing areas of central Florida, particularly the Four-Corners area and both the I-4 and US-27 corridors. Thus, ~s described, the Green Swamp High is not only the springhead of five major rivers in peninsular Florida, it is also the largest of the three major ground-water recharge sources in the peninsula~ Recent hydrologic studies of water available for use in the Southwest Florida Water Management District have shown that, with all potential sources accounted for, we will, for once-only uses here in the District, be using all of nature's annual fresh water replenishment by about 1985. Beyond that, if we are to supply the burgeoning population and industry with needed water, other sources will need to be developed, and .these are costly. It behooves us to protect, de~elop, and conserve the fresh water resources nature has provided for us. And among these, the most important of all is the Green Swamp Higho As part of the Four Rivers Basin Project, Florida, Southwest Florida Water Mlnagement District has acquired, or is in the process of acquiring, 133 square miies of the Green Swamp for flood detention areas. This is divided between the Little Withlacoochee Flood ~tention Area (36.4 square miles) and the Green Swamp Flood Detention Area (96.6 square miles) and amounts to a total of 15.3% of the Green Swamp area (as defined by the U.S. Geological Survey in Florida Geological Survey Report of Investigations No. 4, dated 1966). But this acquirement by Southwest Florida Water Management Di.strict is only about one-seventh of the Green Swamp proper. Would it be necessary and proper for the government (state, federal, or district) to own all the 870 square miles of the Green Swamp? The answer is -6-. .


no; but the gove~nment should own and use for water recharge and conservation purposes as much of the 870 square miles as are normally flooded during most years. In other words, the Green Swamp land that should be allowed to remain . in.private holdings for development should be only those lands that are normally. not flooded in most years. How much land is thus normally flooded? Or saying it in another way, how much land in the Green Swamp should be developed without resorting to extensive and costly drainage and related flood-control works? This is the:crux of the problem. To date there are large areas of the Green Swamp that have never been surveyed to determine land ownership boundaries, much lessto determine the areas that generally are not flooded and, to be developed, would require drainage, roads, water supplies, sewage, and other public services. Lacking the necessary survey data one can only estimate the area, based on study of the most.useful available maps --the United States Geological Survey Topographic Quadrangles --for the area. These maps have ten-foot contour intervals and show areas of swamp, wooded, _ and open lands. The ten-foot contour intervals are almost useless for our present purposes --one needs one-• foot contours, not ten-foot intervals. The Green Swamp is not even covered with modern aerial photos that would allow, by study of the plant assemblages -and topographic features, the discrimination-of generally non-flooded from flooded lands. A study of the U. s. Geological Survey maps and published reports, plus some supplementary knowledge gained from reconnaissance studies of the Green Swamp and surveillance flights over it, indicates that perhaps one-fourth to one-fifth of the Green Swamp may be suitable for limited development. This would be in excess ofthe 133 square miles in the two flood detention areas in the Green Swamp. Thus, 870 133 = 737 x 1/4 = about 184 square miles; or, if one-fifth is suitable, then only about 147 square miles is capable of private development, chiefly as. scattered residences, cattle ranees and farmsteads. The -7-


.o I I rest, about 553 to 590 square miles, should be retained for water supply and I conservation purposes chiefly, but would also serve as public park land, wild life preserve,.and a green belt to serve. the urbanized areas. The _remainder, 147 to 184 square miles is widely scattered through the Green Swamp, generally as _isolated islands or narrow, linear ridges of no great individual size. There is no really large block of ''high land" that could be developed for new towns or similar land developments, without extensive drainage that would be harmful to the swamps and marshes needed for recharge purposes to supply water to the thirsty, growing population outside of the Green Swamp. Further, allowing urbanization or municipal type developments in_ the Gre~n Swamp would carry with it the.seeds of destruction• to the water supply even ff over-drainage were not the cause. The problem is how to dispose of the human, industrial, connnercial, and agricultural _wastes that. would accumulate fro_ m development of the Green swamp lands. Lacking streams to carry away and dilute wa_stes, the poorly drained Green Swamp could well become a huge noisome sump of human and industrial wastes that would ruin the heart of the recharge source for the major _water supply of. central Florida. It is thus concluded, based on the best evidence now available, that the state, federal, or district governments should acquire about 550 to 590 additional square miles of the Green Swamp which is_ much more valuable to the state aid to the nation as the core of the major water-supply source for several million persons than i~-the Big Cypress as a water supply for part of the Everglades National Park and perhaps 50 thousand persons. At current inflated values of about $250 per acre, this would cost $90 million to $100 million and market demands are rising rapidly. These are relatively large sums of money. But we are talking of protecting the core of one of the major sources of water supply for all of southern, peninsular Florida. It is a cost that we must somehow manage to pay, and soon, -8-


• • I for the developer~ are rapidly usurping the land and if allow~d to proceed unchecked will ruin the Green Swamp and its contribution of life-giving water supply for all time. 05-14-73 GGP:ld • I -9-




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