The Green Swamp: Should It Be in Public Ownership? - April 15th, 1973


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The Green Swamp: Should It Be in Public Ownership? - April 15th, 1973

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The Green Swamp: Should It Be in Public Ownership? - April 15th, 1973
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Box 3

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Aquifers -- Hydrogeology -- Everglades (Fla.) ( lcsh )
Hydrology -- Florida -- Biscayne Aquifer (Fla.)

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University of South Florida
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University of South Florida
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G16-00634 ( USFLDC DOI )
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PAGE 1

r. ... ., -I THE GREEN SWAMP: SHOULD IT BE IN PUBLIC OWNERSHIP?. BY .. -i:>~Lt ro. ~Ul oN Peninsular F,lorida, south of a hydrologic di.vi.de that crosses the peninsula in a roughly arcuate line from Cedar Key northeast to Putnam Hall and Florahome, thence s _outheast to New Smyrna Beach, i.s a "hydrologic island." . No rains that fall, no streams that flow, and no ground water that courses through the rocks, crosses this line southward. Therefore~ all water that is available for any use whatsoever south of th;. s line originates as rainfall south of the line. Of the rain that falls in the area south of this line, averaging aoout 55 inches a year, about 73 % or more is lost to evapotranspiration p1ocesses. This is the water that evaporates from all wet surfaces, such as rivers, lakes, swamps, wet soils, wet leaves, wet roofs, and roadways, etc. and that i s transpired, or "breathed" by living organisms, chiefly plants. This loss.,about 40 inches per year, subtracted from the precipitation, leaves about 15 inches for recharge to the aquifers and eventual runoff from the streams. Fifteen inches of annual recharge on one square mile of land surface amounts to about 718,000 gallons per day and t his is roughly the measure of the potential water crop from each square mileof land in all areas of recharge. In other words, starting with our aquifers full, we could harvest 15 inches or 718,000 gallons per day per square mile and not diminish storage in.the aquifers at all. But we could be usin,,. un all the water in the strenms a nd before lon
PAGE 2

. " • . _.. I --Although the Green Swamp is thus not the only recharge area in Central and South Florida, i~ is one of the three most import.int and likewise up to now o.ne of the least developed. It is essential to protect it from "ditchers," "drainers," and "developers," who could ruin it as a source of water. The Green Swamp as defined by the U. S. Geological Survey, comprises about 870 square mile~ -11i.&.~stly in northern Polk and southern Lake Counties, with smaller parts in';eJs~ern-Pasco and Hernando Counties. About 710 square miles or nearly 82% of the 870 square miles is drained (rather poorly) by the Withlacoochee River. The remainder is divided between the Hillsborough, Peace, and Oklawaha River Basins, ~nd a smaller part goes to the Kissimmee River Basin. But these streams are less sources of water supply than they are sources of floodcontrol problems~ The huge Floridan Aquifer acqui~es much of its recharge here,. and it is the ground water from the Florid:m Aauifer that supplies more than 90% of all water supplies utilized in peninsular Florida. Thus, as described, the Green Swamp 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 ~or use in the Southwest Florida Water Management District have shown that, with all potential sources accounted fo.r, we will, for once-only uses, 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, develop, and conserve the'fresh waterresoUTces nature has provided for us. And among these, perhaps the most important of all is the Green Swamp. As part of the Four Rivers Basin project, Florida, Southwest Florida Water }~nagement District has acquired, or is in the process of acquiring, 133 square mi.les of the Green Swamp for flood detention areas. 1bis is divided between the Little Withlacoochee Flood Detention Area (36.4 square miles) and the Green Swamp Flood Det .ention 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 District is only about one-seventh of the total Green Swamp area. Would it be necessary and proper for the government (state, federal, or distri.ct) to own all the 870 square miles of the defined Green Swamp? The answer is no~ but the government should own and use for water recharge and conservation purposes as much of the 870 square miles as are normally flooded by the 25-year flood. In other words, the Green Swamp land that should be allowed .to remai . n i.n private h~ldings for development, should be only those lands that are norm~lly not flooded by the 25~year flood. How much land is thus normally flooded? Or saying i.t in another way, how much land i.n the Green Swamp should be developed without resorting to 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 less to determine the areas that generally are not flooded and, to be developed, would require drainage, roads, water supplies, sewage_ , and other public services •

PAGE 3

• • .. : 0 • • , ' . 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 onefoot contours, not ten-foot intervals. The Green Swamp area 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, plus some supplementary knowledge gained from brief trips through the Green Swamp area and surveillance flights over it, indicat_es that perhaps one-fourth to one-f~fth of the Green Swamp area may be suitable for limited development~ This would be in excess of the 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 suitable for private dev~lopment, chiefly as scattered residences and.farmsteads. The rest, about 553 to 590 square miles, should be retained for water supply and 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 throug h 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 wouid be hannfu. l 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 Green Swamp would carry with it the seeds of destruction to the water supply even if 0ver-drainage were not the cause. The problem is how to 0dispose of the human, ind'.lstrial, commercial, and agricultural wastes that wou1d accurnuiate from development of the Green Swamp lands. Lacki.ng streams to carry away and dilute wastes, the poorly drained Green Swamp could well become~ huge noisome sump of human and i .ndustri_al waste s that would ruin the recharge' source for the major water supply of Central Florida. As this essay concludes,' based on the best evidence now available, the state, federal, or district governments should acquire about 5 ~ 0 to 590 additional square miles of the Green Swamp. At current inflated values of ~bout $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 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, for the developers are rapidly usurping the land and if allowed to proceed unchecked will ruin the Green Swamp for all time • . 04-15-73 . . . .

PAGE 4

I FROM THE DES~_OF THE CHIEF HYDROLOGIST: The Green Swamp Should it be in Public Ownership? Peninsular Florida, south of a hydrologic divide that crosses the peninsula in a roughly arcuate line from Cedar Key northeast to Putnam Hall and Florahome, thence southeast to New Smyrna Beach, is a ''hydrologic island." No rains that fall, no streams that flow, and no ground water that courses through the rocks, crosses this line southward. Therefore, all water that is available for any use whatsoever south of this line originates as rainfall south of the line. Of the rain that falls in the area south of this line, averaging about 55 inches a year, about 73 % or more is lost to evapotranspiration processes. This is the water that evaporates from all wet surfaces, such as rivers, lakes, swamps, wet soils, wet leaves, wet roofs, and roadways, etc. and that is transpired, or '~reathed" by living organisms, chiefly plants. This loss, about 40 inches per year, subtracted from the precipitation, leaves about 15 inches for recharge to the aquifers and eventual runoff from the streams. Fifteen inches of annual recharge on one square mile of land surface amounts to about 718,000 gallons per day and this is roughly the measure of the potential water crop from each square mile of land in all areas of recharge. In other words, starting with our aquifers full, we could harvest 15 inches or 718,000 gallons per day per square mile and not diminish storage in the aquifers at all. But we would be using up all the water in the streams and before long they would dry up! So we have to settle for some lower yield, perhaps about one-third the runoff, or 5 inches per square mile. This would yield us roughly about 240,000 gallons per day per square mile. But much of the land area of Florida south of the peninsular hydrologic divide either discharges water (as most of our river and coastal swamp lands do) or the Floridan Aquifer is so deeply buried beneath overlying impermeable deposits of dense clay, silt, and marl, that no local recharge takes place. As a result we depend upon

PAGE 5

three main (but not sole) recharge areas, namely: (1) the Green Swamp High; (2) rhe Pasco High, which centers about 40 miles due west of the Green Swamp; and (3) the Alachua-Putnam High, which centers about 110 miles north of the Green Swamp and is dissected by the peninsular hydrologic divide. 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 Alachua-Putnam 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 serves an even larger area, including in part the Upper St. Johns B asin, the Peace River Basin, and the coastal area from Charlotte County north to Tampa. Although the Green Swamp 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 "ditchers," "drainers," and "developers," who could ruin it as a source of water. 'nle Green Swamp as defined by the U. s. Geological Survey, comprises about 870 square miles lying mostly in northern Polk and southern Lake Counties, with smaller parts in southern Sumter and in eastern Pasco and Hernando Counties. About 710 square miles or nearly 82% of the 870 square miles is drained (rather poorly) by the Withlacoochee River. The remainder is divided between the Hillsborough, Peace, and Clclawaha River Basins, and a smaller part goes to the Kissimnee River Basin. But these streams are less sources of water supply than they are sources of flood-control problems. The huge Floridan Aquifer acquires much of its recharge here, and it is the ground water from the Floridan Aquifer that supplies more than 90% of all water supplies utilized in peninsular Florida. Thus, as described, the Green Swamp 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,

PAGE 6

with all potential sources accounted for, we will, for once-only uses, 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 c ostly. It behooves us to protect, develop, and conserve the fresh water resources nature has provided for us. And among these, perhaps the most important of all is the Green Swamp. As part of the Four Rivers Basin Project, Florida, Southwest Florida Water Management Di.strict has acquired, or is in the process of acquiring, 133 square miles of the Green Swamp for flood detention areas. This is divided between the Little Withlacoochee Flood Detention 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 G eological Survey Report of Investigations No. 4, dated 1966). But this acquirement by Southwest Florida Water Management District is only about one-seventh of the total Green Swamp area. Would it be necessary and proper for the government (state, federal, or district) to own all the 870 square miles of the defined Green Swamp? The answer is no; but the government should own and use for water recharge and conservation purposes as much of the 870 square miles as are normally flooded by the 25-year flood. 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 by the 25-year flood. 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 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 less to determine the areas that generally are not flooded and, to be developed, would require drainage, roads, water supplies, sewage, and other public servies.

PAGE 7

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 area 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, plus some supplementary knowledge gained from brief trips through the Green Swamp area and surveillance flights over it, indicates that perhaps one-fourth to one-fifth of the Green Swamp area may be suitable for limited development. This would be in excess of the 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 suitable for private development, chiefly as scattered residences and farmsteads. The rest, about 553 to 590 square miles, should be retained for water supply and 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 Green Swamp would carry with it the seeds of destruction to the water supply even if over-drainage were not the cause. The problem is how to dispose of the human, industrial, commercial, and agricultural wastes that would accumulate from developmant of the Green Swamp lands. Lacking streams to carry away and dilute wastes, the poorly drained Green Swamp could well become a huge noisome s\Jmp of human

PAGE 8

and industrial wastes that would ruin the recharge source for the major water supply of Central Florida. As this essay concludes, based on the best evidence now available, the state, federal, or district governments should acquire about 550 to 590 additional square miles of the Green Swamp. At current inflated values of about $250.00 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 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, for the developers are rapidly usurping the land and if allowed to proceed unchecked will ruin the Green Swamp for all time. GARALD G. PARKER,C.P.G. Senior Scientist and Chief Hydrologist 04-24-73

PAGE 9

THE GREEN SWAMP: SHOULD IT BE IN PUBLIC OWNERSHIP?. BY GARALD G. PARKER, C.P.G. !} Peninsular Florida, south of a hydrologic divide that crosses the peninsula in a roughly arcuate line from Cedar K e y northeast to Putnam Hall and Florahome, thence southeast to New Smyrna Beach, i.s a "h ydrologic island." No rains that fall, no streams that flow, and no ground water that courses through the rocks, crosses this line southward. Therefore, all water that is available for any use whatsoever south of t~ls line originates as rainfall south of ~he line. Of the rain that-falls in the area south of this line, averaging about 55 inches a year, about 73% or more is lost to evapotranspiration p1ocesses. This is the water that evaporates from all wet surfaces, such as rivers, lakes, swamps, wet soils, wet leaves, wet roofs, and roadways, etc. and that is transpired, or "breathed" by living organisms, chiefly plants. This loss.,about 40 inches per year, subtracted from the precipitation, leaves about 15 inches for recharge to the aquifers and eventual runoff from the streams. Fifteen inches of annual recharge on one square mile of land surface amounts to about 718,000 gallons per day and this is roughly the measure of the potential water crop from each square mile of l and in all areas of recharge. In other words, starting with our aquifers full, we could harvest 15 inches or 718,000 gallons per day per square mile and not diminish storage in the aquifers at all. But we could be using up all t h e water in the streams a nd before l ong thev Pould ~ry up! So we have to settle for some lower yield, perhaps about one-third the runoff, or 5 inches per square mile. This would yield us roughly about 240,000 gallons per day per square mile. But much of the land area of Florida south of the peninsular hydrologic divide either dis~harges water (as most of our river and coastal swamp lands do) or the Floridan aquifer is so deeply buried beneath overlying impermeable deposits of dense clay, silt, and marl, that no local recharg e takes place. As a result we depend upon three main (but not sole) recharge areas, namely: (1) the Green Swamp High; (2) the Pasco High, which centers about 40 -miles due west of the Green Swamp; and (3) the Ai'achua-Putnam High, which centers about 110 miles north of the Green Swamp and is dissected by the peninsular hydrologic divide. The Pasco High furnishes most of the water SUP.ply to the coastal area from Tampa (including about one-half of Tampa's supply) north to and beyond Weeki Wachee . The Alachua-Putnam 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 serves an even larger area, i.ncluding in part the Upper St. Johns Basin, the Peace River Basin, and the coastal area from Charlotte County north to Tampa. !/ Chief Hydrologist and Senior Scientist, Southwest Florida Water Management District, Brooksville, Florida

PAGE 10

. . Although the Green Swamp is thus not the only recharge area in Central and South Florida, i; is one of the three most important and likewise up to now one of the least developed. It is essential to protect it from "ditchers," "drainers," and "developers," who could ruin it as a source of water. The Green Swamp as defined b y the U. S. Geological Survey, comprises about 870 square miles l ying mostly in northern Polk and southern Lake Counties, with smaller parts in eastern Pasco and Hernando Counties. About 710 square miles or nearly 82% of the 870 square miles is drained (rather poorly) by the Withlacoochee River. The remainder is divided between the Hillsborough, Peace, and Oklawaha River Basins, and a smaller part goes to the Kissinnnee River Basin. But these streams are less sources of water supply than they are sources of floodcontrol problems. The huge Floridan Aquifer acquires much of its recharg e here,. and it is the a-round watai: -r-0 t h Elori..da A ouifer that lies more than 90% of 11 water su lies utilized in Thus, as described, the Green Swamp is not only the springhead of five major rivers in peninsular Florida, it is also the largest of the three major ground water recharg e sources in the peninsula. Recent hydrologic studies of water available for use in the Southwest Florida Water M.'lnag ement District have shown that, with all potential sources accounted for, we will, for once-only uses, be using_ all of nature's annual f resh 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, develop, and conserve the fresh water resources nature has provided for us. And among these, perhaps the most important of all is the Green Swamp. As part of the Four Rivers Basin project, Florida, Southwest Florida Wate r Manage ment District has acquired, or is in the process of acquiring, 133 square mi.les of the Green Swamp for flood detention areas. This is divided between the Little Withlacoochee Flood Detention 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 b y the U. S. Geological Survey in Florida Geological Survey Report of Investigations No. 4, dated 1966). But this acquirement by Southwest Florida Water Management District is only about one-seventh of the total Green Swamp area. Would it be necessary and proper for the government (state, federal, or distri.ct) to own all the 870 square miles of the defined Green Swamp? T h e answer is no: but the government should own and use for water recharg e and conservation purposes as much of the 870 square miles as are normally flooded by the 25-year flood. In other words, the Green Swamp land that should be allowed .to rema i n i.n private holdings for development, should be only those lands that are normally not flooded by the 25~year flood. How much land is thus normally flooded? Or saying i.t in another way, how much land i.n the Green Swamp should be developed wi.thout resorting to 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 less to determine the areas that generally are not flooded and, to be developed, would require drainage, roads, water supplies, sewage, and other public services.

PAGE 11

... ,., " ., "' . 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 onefoot contours, not ten-foot intervals. The Green Swamp area is not even covered with modern aeria l 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, plus some supplementary knowledge gained from brief trips through the Green Swamp area and surveillance flights over it, indicates that perhaps one-fourth to one-fifth of the Green Swamp area may be suitable for limited development. This would be in excess of the 133 square miles i.n 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 suitable for private development, chiefly as scattered residences and farmsteads. The rest, about 553 to 590 square miles, should be retained for water supply and 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 throug h the Green Swamp, generally as isolated islands or narrow, linear ridges of no great individual size. There is no really larg e block of "high land" that could be developed for new towns or similar land developments, without extensive drainag e that would be hannfu_ l 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 t ype developments in the Green Swamp would carry with it the seeds of destruction to the .water supply even if over-drainag e were not the cause. The problem is how to dispose of the human, ind~strial, commercial, and a gricultural wastes that wou1d accumu1~te from deve1opment of t h e Green Swamp lands. L~cking streams to carry awa y and dilute wastes, the poorly drained Green Swamp could well become~ huge noisome sum~ of human and industrial wastes that would ruin the recharge source for the major water supply of Central Florida. As this essay concludes, based on the best evidence now available, the state, federal, or di.strict governments should acquire about 5 , 0 to 590 additional square miles of the Green Swamp. At current inflated values of ~bout $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 one of the major sources of water supply for all of southern, peninsular Florida. It is a cost that we must somehow mana g e to pay , and soon, for the developers are rapidly usurping the land and if allowed to proceed unchecked will ruin the Green Swamp for all time. ~;--' 04-15-73 -3-

PAGE 12

\ THE GREEN SWAMP: SHOULD IT BE IN PUBLIC OWNERSHIP? BY I GARALD G. PARKER, C.P.G. !/ Peninsular Florida, south of a hydrologic divide that crosses the peninsula in a roughly arcuate line from Cedar Key northeast to Putnam and Florahome, thence southeast to Daytona Beach, is a "hydrologic island." No rains that fall, no streams that flow, and no ground water that courses through the rocks, crosses this line. Therefore, all water that is available for any use whatsoever south of this line originates as rainfall south of the line. Of the rain that falls in the area south of this line, averaging about 55 inches a year, about 73% or more is lost to evapotranspiration processes. This is the water that evaporates from all wet surfaces, such as rivers, lakes, swamps, wet soils, wet leaves, wet roofs, and roadways, etc. and that is transpired, or "breathed" by living organisms, chiefly plants. This loss,,about 40 inches per year, subtracted from the precipitation, leaves about 15 inches for recharge to the aquifers and eventual runoff from the streams. Fifteen inches of annual recharge on one square mile of land surface amounts to about 718,000 gallons per day and this is roughly the measure of the potential water crop from each square mile of land in all areas of recharge. In other words, starting with our aquifers full, we could harvest 15 inches or 718,000 gallons per day per square mile and not diminish storage in the aquifers at all. But we could be using up all the water in the streams and before long they would dry up! So we have to settle for some lower yield, perhaps about one-third the runoff, or 5 inches per square mile. This would yield us roughly about 240,000 gallons per day per square mile. But much of the land area of Florida south of the peninsular hydrologic divide either discharges water (as most of our river and coastal swamp lands do) or the Floridan aquifer is so deeply buried beneath overlying impermeable deposits of dense clay, silt, and marl, that no local recharge takes place. As a result we depend upon three main (but not sole) recharge areas, namely: (1) the Green Swamp High; (2) the Pasco High, which centers about 40 miles due west of the Green Swamp; and (3) the Alachua-Putnam High, which centers about 110 miles north of the Green Swamp and is dissected by the peninsular hydrologic divide. 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 Alachua-Putnam 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 serves an even larger area, including in part the Upper St. Johns Basin, the Peace River Basin, and the coastal area from Charlotte County north to Tampa. !/ Chief Hydrologist and Senior Scientist, Southwest Florida Water Management District, Brooksville, Florida

PAGE 13

Although the Green Swamp 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 "ditchers," "drainers," and "developers," who could ruin it as a source of water. The Green Swamp as defined by the U. s. Geological Survey, comprises about 870 square miles lying mostly in northern Polk and southern Lake Counties, with smaller parts in eastern Pasco and Hernando Counties. About 710 square miles or nearly 82% of the 870 square miles is drained (rather poorly) by the Withlacoochee River. The remainder is divided between the Hillsborough, Peace, and Oklawaha River Basins, and a smaller part goes to the KissilJDllee River Basin. But these streams are less sources of water supply than they are sources of floodcontrol problems. The huge Floridan Aquifer acquires much of its recharge here, and it is the ground water from the Floridan Aquifer that supplies more than 90% of all water supplies utilized in peninsular Florida. Thus, as described, the Green Swamp 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, 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, develop, and conserve the fresh water resources nature has provided for us. And among these, perhaps the most important of all is the Green Swamp. As part of the Four Rivers Basin project, Florida, Southwest Florida Water Manage ment District has acquired, or is in the process of acquiring, 133 square m iles of the Green Swamp for flood detention areas. This is divided between the Little Withlacoochee Flood Detention 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 District is only about one-seventh of the total Green Swamp area. Would it be necessary and proper for the government (state, federal, or district) to own all the 870 square miles of the defined Green Swamp? The answer is no; but the government should own and use for water recharge and conservation purposes as much as the 870 square miles as are normally flooded by the 25-year flood. 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 by the 25-year flood. 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 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 less to determine the areas that generally are not flooded and, to be developed, would require drainage, roads, water supplies, sewage, and other public services. -2-

PAGE 14

[ • \ Lacking the necessary survey data one can only estimate the area, based on study of the most useful available maps --the United States G eological 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 onefoot contours, not ten-foot intervals. The Green Swamp area 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, plus some supplementary knowledge gained from brief trips through the Green Swamp area and surveillance flights over it, indicates that perhaps one-fourth to one-fifth of the Green Swamp area may be suitable for limited development. This would be in excess of the 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 suitable for private development, chiefly as scattered residences and farmsteads. The rest, about 553 to 590 square miles, should be retained for water supply and 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 Green Swamp would carry with it the seeds of destruction to the water supply even if over~drainage were not the cause. The problem is how to dispose of the human, industrial, commercial, and agricultural wastes that would acculiltilate rr0111 development of the Green Svaalp lands. t.ackirtg streams to carry away and dilute wastes, the poorly drained Green Swamp could well become a huge noisome sump of human and industrial wastes that would ruin the recharge source for the major water supply of Central Florida. As this essay concludes, based on the best evidence now available, the state, federal, or district governments should acquire about 550 to 590 additional square miles of the Green SWamp. At present inflated costs of about $250 per acre, this would cost about $88 million to $94.4 million. These are relatively large sums of money. But we are talking of protecting 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, for the developers are rapidly usurping the land and i f allowed to proceed unchecked will ruin the Green Swamp for all time. 04-15-73 -3-

PAGE 15

Fro• tH deA or Ille Cltid Hydrolo1i11 : Part I The Green Swamp Should It Be In Public Ownership? .re;. R~ L47.3 Peninsular Florida, south of a hydrologic divide that c rosses the penin sula in a roughl y accurate line from Cedar Ke y northeast 10 Putnam Hall and Florahome. thence southeast to New Smyrna Bcaoh, i s a " h ydrologic i sland . " No rains that fall, no streams that 0ow. and no ground water that courses through the rocks , crosses this line southward. Therefore, all water that is available for any use whatsoever south of this line originates as rainfall south ofthe line. Of the rain tha1 falls in the area south of this line, averaging ' about 55 inches a year, 73% or more is lost to evapotranspiration processes. This is the water that evaporates from all wet surfaces , such as rivers , lakes, swamps , wet soib, wet leaves. wet roofs, and roadways and that is transpired, or ""breathed" by living organisms, chiefly plantS . This loss , about 40 inches per year . subtrac1ed from the precipitation, leaves about I 5 inches for recharge to the aquifers and for eventua l runoff from the streams. Fifteen inches of annual recharge on one square mile of land surface amounts to about 7 I 8 .000 gallons per day which is rouct,ly the measure of the potential water crop from each square mile of land in all areas of recharge . In other words, starting with our aquifers full , we could harvest 15 inches or 718,000 gallons pe r day per square mile and not d iminish storage in the aquifers at all . Bal we woeld be Ille ... tit• bo(ore loa& tltoy woe Id dry So we have to settle for some lower yield, perhaps about onethird the runoff, or S inches per square mile . This would yield us roughly about 240,000 gallons per day per square mile . P . 0 . BOX 457 BROOKSVILLE , FLORIDA 33512 Unfortunate l y. much of the land area of Florida south of 1he peninsular hydrologic divide. ei1her dischar1n waler (as most of our rive r and coas1al swamp lands do) or lo cal recharge i s difficult because the F lorida Aquifer is so deeply buried beneath overlying im permeable deposits of dense clay, sail and marl. A s a result w e depend upon three ma i n ( but not so le ) recharg e areas , namely: (I) th e Green Swamp H igh ; (2) the Pasco High, which ce nters abou1 40 miles due west of the Green Swamp ; and (3) the Alachua Putnam H i gh , which cen ter s about I IO mi Jes n onh of the Green Swamp and is dissected by the peninsu lar hydrologic divide . 1 The Pasco High furnishes most of the water supply to the coastal area from Tampa (including about onehalf of Tampa ' s supp l y) north to and beyond Week i Wachee . The Alachua-Putnam High serves a vast •~ca i ncluding part of Suwanee Basin+ partJof .the SjJver Springs Basin , part of the Rainbow Springs Basin, and much of the Upper St. Johns Buin. The Green Swamp serves an even larger area, includ in g in part the Upper St. Johns Basin , the r Peace River Basin , and the coutal area from Charlone County north to Tampa. Although the Green Swamp is not the only recharge area in Central and South Florida. it is one o(:;he three most important and up to now one of the least developed . h is essential t o protect it from '"ditchers" "drainers," and "devcl ~ open;• who could r1:1in i1 as a source of water . The Green Swamp u defined by the U . S . Geological Survey , comprises about 870 square miles lyi!"& mos tly in northern Polk and southern Lake Counties, \ with smaUcr parts in southern Sumte r and in ea.stern Pasco and Hernando Coun1ics . About 7 IO ,quarc miles or. nearly 82 % or the 870 square miles is drained (rather poorly) by the Withlacoochee River. The remainder is divided between the Hillsborough , Peace and Oldawaha River Buins, and a smaller part goes to the Kissimmee River Basin. But these streams a r c less so ur ces of water s uppl y 1han they are sources of flood-control problems . The huge Floridan Aquifer acqu i re s much of its recha rg e here , and it is the around water 1 from the Florid•• ••P plies more tluin 90% of ..-ater ,.,. plies utilizetl in • Thus, the Green Swamp is no1 only the springhcad of five major rivers in pen i n sular Florida, i t is als o the largest of the three major ground water recharge sources in lhe peninsula. Recen t hydrologic studies of water avai lable for use i n th e Southwest Florida Water Management District have shown that , with all poteatial sources accounted for, we will , for once-only uses.,. be using all of nature' s annual fresh water replenish ment by about 1985. Beyond that , if we arc lo supp l y the burgeoning population and industry with needed wa1er , other sources will need to be developed, and these arc costly . To Be Cont inued Nu.1 Month GARALD G . PARKER, CP.G ... Senior Scientist and ..,.. Chier Hydrologist v U-A-CJ~ '73 HYDRO SCOPE (J

PAGE 16

Fro• tH desk or tH Chief Hydroloalse-: Part II T he Green Swamp S h o ul d I t B e In Public Ownership? !:r::PT-OCT '79 ( In the last edition. Mr. Parker d iscuued the size , the recharge capa c i ty and the water suppl y polential o f th e Green Swamp . This month he c o nclude s his discussion of the area , focus i ng on which parts of i t need t o be public ownership and why .) It behooves us to protect, develop . and conserve the fresh water resources nature has provided for us. And among these, perhaps the most important of all is the Green Swamp . As part of the Four Rivers Basin Project, Florida, the District has acqufred, or is acquiring , 133 square miles of the Green Swamp for flood detention a r eas . This is divided between the Little Withlacoochee flood Deten • tion Area (36. 4 square miles ) and the Green Swamp Flood Detcn1ion Arca (96 . 6 square miles) and amounts to a total of I 5.3% of the G r een Swamp area (as d efined by the U . S . Geological Survey in Florida Geological Survey Report of lnveatigations No . 4, dated 1966) . B u t this acquirement by the Southwest Florida Water Management District is only about one•seventh of the total Green Swamp area. Would it be necessary and proper for the government (state, federal, or district) to own all the 870 square miles of the defined Green Swamp'? The answer is no; but the government should own and use for water recharge and con• servation purposes as much of the 870 tquare miles as are normally flooded by the 25-year flood. In other words , the Green Swamp la n d that ahou l d . be allowed to remain in private holdings for development, shoul d be only those lands that are formally not nooded by the 25 P . 0 . BOX 457 BROOKSVILLE, FLORIDA 33512 yea r flood . How much land i s thu s nor• mall y nooded? Or saying it i n an o ther way. h o w much land in the Green Swamp should be developed without resort i ng t o drai n a ge and related flo o d control works ? This i s the crux of the problem . To date there are large areas of the Green Swamp that have never been sur• veyed t o determine land ownership boundaries . much less t o determ i ne the areas that gene r all y arc not flooded and , to be deve l oped. would require drai nage , r o ad s , water s upplie s. sewage and other pub lic serv i ce s . Lacking the necessary survey data one can o nl y estimat e the area, based o n study of the most useful available maps the United Statea Geological Survey Topographic Quadrangles -for the area . These maps have ten-foot contour intervals and sho~ areas of swamp . wooded and open lands. However . the ten.foot contour intervals ate almost useless for our present pu.tposes -one needs one.foot contoun, not tcn-fooHn-~ tcrvals . The Green Swamp area 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. plus some supplementary knowledge gained from brief trips through the Green Swamp area and surveillance flights o~r it, indicates that perhaps one-founh: to one-fifth of the Green Swamp area ~ may be suitable for limited development. This would be in excess of the: I 33 square miles in the two flood detention areas in the Green Swamp . Thus , 870 • , 133 equals 737 x 1/4 equals about 184 square miles; or, if one fifth is auitable, then only about 147 square miles arc suitable for private development, chi.efly as scattered resi d ences and farmsteads. The rest, about 553 to 590 tqure miles, ahould be retained for watet supply and conaervation purposes : chiefly, but would also serve as public park land , wild life preserve , and as a green belt to Jerve the urbaniz.cd areas . The rem a in i ng 147 t o 1 84 squ a r e m il e s are widel y scattered through the Green Swamp , generall y as i solated islands or narrow, linear ridges of no great individua l size . There is n o reall y large block of "'high land"' that could be developed for new towns or similar land developments without ex • tensive drainage . Such drainage would be harmful to the swamps and marshes needed for recharge purpose s to supply wa1er to the thirsty , growing population outside of the Green Swamp . Further, allowing urbanizat i on or municipa l type developments in the Green Swamp wou l d carry with it the seeds o f destruction t o the water supply even if over•drainage were not the cause . The problem would be how to diapose of the human, in dustrial, commercial and agricultural wastes that would accumulate from deve lopment of the Green Swamp lands . Lacking streams to carry away and dilute wastes , the poorly drained Green Swamp . could well become-;1 buge floisome sump of human and industrial wastes that would ruin the recharge sou r ce for the major water supply of Central Florida. As this essay concludes , based on the best evidence now available , the state . federal, or district governments should acquire about 550 to 590 additional square miles of the Green Swamp . At current innated values of about S250 .00 per acre , this would cost S90-million to S100-million and market demand s arc r i sing rapidly . These arc relatively large sums of money . But we arc talking of protecting 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 . for the developers are rapidly usurpin& the land and if allowed to proceed unchecked will ruin the Green Swamp for all time . GARALD G . PARKER , C . P . G . Senior Scientist and {O _ / l ;1 ,0 Chief Hydrologist .,/I


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