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FLRD GEOLOSk ( IC SUfRiW COPYRIGHT NOTICE [year of publication as printed] Florida Geological Survey [source text] The Florida Geological Survey holds all rights to the source text of this electronic resource on behalf of the State of Florida. The Florida Geological Survey shall be considered the copyright holder for the text of this publication. Under the Statutes of the State of Florida (FS 257.05; 257.105, and 377.075), the Florida Geologic Survey (Tallahassee, FL), publisher of the Florida Geologic Survey, as a division of state government, makes its documents public (i.e., published) and extends to the state's official agencies and libraries, including the University of Florida's Smathers Libraries, rights of reproduction. The Florida Geological Survey has made its publications available to the University of Florida, on behalf of the State University System of Florida, for the purpose of digitization and Internet distribution. The Florida Geological Survey reserves all rights to its publications. All uses, excluding those made under "fair use" provisions of U.S. copyright legislation (U.S. Code, Title 17, Section 107), are restricted. Contact the Florida Geological Survey for additional information and permissions. STATE OF FLORIDA STATE BOARD OF CONSERVATION DIVISION OF GEOLOGY FLORIDA GEOLOGICAL SURVEY Robert O. Vernon, Director REPORT OF INVESTIGATIONS NO. 37 GEOLOGY AND GROUND-WATER RESOURCES OF GLADES AND HENDRY COUNTIES, FLORIDA By Howard Klein, M. C. Schroeder, and W. F. Lichtler U. S. Geological Survey Prepared by the UNITED STATES GEOLOGICAL SURVEY in cooperation with the FLORIDA GEOLOGICAL SURVEY and the CENTRAL AND SOUTHERN FLORIDA FLOOD CONTROL DISTRICT Tallahassee 1964 AGRI- FLORIDA STATE BOARD cULTRM F LIBRARy OF CONSERVATION FARRIS BRYANT Governor TOM ADAMS Secretary of State J. EDWIN LARSON Treasurer THOMAS D. BAILEY Superintendent of Public Instruction RICHARD ERVIN Attorney General RAY E. GREEN Comptroller DOYLE CONNER Commissioner of Agriculture W. RANDOLPH HODGES Director LETTER OF TRANSMITTAL florida C eological Survey Callabassee October 10, 1964 Honorable Farris Bryant, Chairman Florida State Board of Conservation Tallahassee, Florida Dear Governor Bryant: The Division of Geology is publishing, as Florida Geological Survey Report of Investigations No. 37, a report on the "Geology and Ground-Water Resources of Glades and Hendry Counties, Florida," which was prepared by Howard Klein, M. C. Schroeder, and W. F. Lichtler, as a part of a cooperative program between the U. S. Geological Survey and the Florida Geological Survey. Both Glades and Hendry counties obtain water from the Flori- dan aquifer, generally by artesian flow, and from several shallow aquifers. Recharge of the artesian aquifer occurs over these counties and in Polk County. The report is a continuation of a series, which is designed ultimately to present the geologic and hydrologic facts of all of the State. Only in this way, can the State be guaranteed a conservative and adequate development of its water and associated resources. Respectfully yours, Robert O. Vernon Director and State Geologist Completed manuscript received August 7, 1963 Published for the Florida Geological Survey By E. O. Painter Printing Company DeLand, Florida 1964 iv CONTENTS Abstract _.._ -- -____.--------......... -------------- ----.. --. --- 1 Introduction ---___. -._-----.__...................___..___--_..---- 2 Purpose and scope of investigation _------------ 2 Acknowledgments 3------------- ---_--------- 3 Previous investigations---- -_--------.__ ---------3.------ 3 Geography __--___ ._...__ --- ----------- ___ ----.-----.-----_ --- 5 Location of area 5~ General land features and drainage ....__.__...--- -------- ----- 5 Everglades _---.-----_--------------_------_------------- 5 Sandy Flatlands -_---------------.---------------------.---- -----. 7 Big Cypress Swamp .......-----------.-_ _-------.---------- 7 Drainage ..---~_....- ...- ------------------_.------ ------ 9 Climate ---..------_ ......__. .....---- --- ------------- 10 Development and growth of area ------.-- ------------ ------ 11 Geologic formations and water-bearing characteristics -------12 Eocene Series ---_------------------------------ ------ 12 Lake City Limestone ----------__--------------------------- 14 Avon Park Limestone .-----------_.--.__---- ----- ------- 16 Ocala Group .---_-------_ ---------------- -.. -----. .--------- ---------- 18 Oligocene Series -__----- --------__-------- 20 Suwannee Limestone .....----------_.-----_------ ---20 Miocene Series .-------.----- ---- __-- -_ ----- ----- 21 Tampa Formation _----____----_-___ ---- ---. -----21 Hawthorn Formation -.___-- __-------- 22 Tamiami Formation ---_- ...-- __.....-- ------- 24 Pliocene Series __---..-. -_---_--------------------- 25 Caloosahatchee Marl ___ __-_ __ ----. 25 Pleistocene Series -------------------------------26 Anastasia Formation 26 Fort Thompson Formation ___--- --27 Terrace deposits ---.-- -_-------- 29 Recent Series ____-_- --- 30 Lake Flirt Marl -.------.------- ._------------ ----30 Organic soils -- ------------------ 30 Ground water ..------....----.. --. _---- --__-- --. -- ----------- ----- ------ 31 Occurrence and movement __-_____ _31 Floridan aquifer -32 Piezometric surface ---- --------- ----- 39 Recharge 39 Discharge ___- --------------------------------------41 Discharge 41 Water-level fluctuations ----------------------------- 41 Shallow aquifers --------------- ----____---------- 43 Water-level fluctuations -----------------45 Recharge and discharge --- ----------- 47 Hydraulic characteristics ----------------------------------- ----49 Quality of water ---...... --....---.----- -----------58 Hardness __---------------------------- 62 Total dissolved solids _- 62 Specific conductance -__ -__ 67 Hydrogen-ion concentration (pH) 68 Iron (Fe) 68 Calcium (Ca) and magnesium (Mg) ____ 69 Sodium (Na) and potassium (K) 69 Bicarbonate (HCO3) 70 Sulfate (SO4) 70 Chloride (Cl) 70 Fluoride (F) 74 Silica (SiO,) 74 Nitrate (NO3) --------------------- 75 Hydrogen sulfide (H1S) -- ----- ----75 Salt-water contamination ____ 76 Direct encroachment _______- 76 Upward leakage ___--_-----76 Incomplete flushing ___80 Utilization of ground water _______ 81 Irrigation _81 Municipal supplies 82 Other uses __ 83 Summary 83 References __-_______ 85 Well logs -----___ 88 ILLUSTRATIONS Figure Page 1 Location of Glades and Hendry counties 4 2 Glades and Hendry counties showing physiographic regions and the directions of surface drainage __ __--_- 6 3 Approximate extent of Pleistocene terraces in Glades and Hendry counties ______ 8 4 Glades and Hendry counties showing the locations of geo- logic sections and included wells _____ 15 5 South-north geologic section A-A' through Glades and Hendry counties ________ 16 6 South-north geologic section B-B' through Glades and Hendry counties 17 7 West-east geologic section C-C' through Hendry County 18 8 South-north geologic section D-D' along the western shore of Lake Okeechobee __ ____ 19 9 Glades County showing the locations of wells 33 10 Hendry County showing the locations of wells __34 11 LaBelle and vicinity showing the locations of wells 35 12 Clewiston and vicinity showing the locations of wells 36 13 Graphs showing distribution of flow in selected wells in Glades and Hendry counties _____--___ __ 38 14 Glades and Hendry counties showing the configuration of the piezometric surface of the Floridan aquifer, 1958 ----- __--------__- 40 15 Profiles of the piezometric surface of the Floridan aquifer in Glades and Hendry counties, 1958 ___43 16 Hydrographs of wells 3 and 5 in Hendry County and well 131 in Collier County ________ 46 17 Hydrographs of well 234 and the Caloosahatchee River at LaBelle compared with rainfall for the period 1953-54 48 18 Coefficients of transmissibility and storage determined at test sites in Glades, Hendry, and Collier counties in shallow aquifers ___________ _~_ ______.___. 50 19 Composite of semilogarithmic distance-drawdown graphs of five aquifer tests _51 20 Time-drawdown graphs of water levels in observation wells, and sketches showing locations of wells used in aquifer tests 52 21 Semilogarithmic time-drawdown graphs of four observation wells in test area E __-_ .... --__ __ -------------.-.._.....__. 56 22 Semilogarithmic time-drawdown graphs of observation wells in test areas B and D _--- --____----_-- _--_- __----_.___ 57 23 Graphs showing drawdowns expected at different distances from a well pumped at selected rates in each of six test areas 59 24 Graph showing the relation between specific conductance and total dissolved solids in water samples from Glades and Hendry counties ____ 68 25 Graph showing the suitability of ground water for irriga- tion (after Wilcox 1948, p. 25-26) 71 26 Glades and Hendry counties showing the chloride content of water samples from wells tapping the Floridan aquifer, 1952-53, 1958 ____ ___ 72 27 Glades County showing the chloride content of water samples from wells tapping shallow aquifers, 1952-53 73 28 Part of eastern Glades County showing the chloride content of water samples from wells tapping shallow aquifers, 1952-53, 1959 74 29 Hendry county showing the chloride content of water samples from wells tapping shallow aquifers, 1952-53, 1958 75 30 Clewiston area showing the chloride content of water samples from wells tapping the shallow aquifer, 1952-53 ---....-. -__-- 76 31 Part of northwestern Hendry County showing the chloride content of water samples from wells tapping deep and shal- low aquifers, 1952-53, 1958 _77 32 LaBelle showing the chloride content of water samples from wells tapping the shallow aquifer, 1952-53 ___ 79 33 LaBelle showing (by isochlor lines) areas of equal chloride content of water from the shallow aquifer, 1952-53 -- ____ 80 TABLES Table Page 1 Average temperature (oF) at Moore Haven and LaBelle, 1935-56 _____ ---------_______ 10 2 Rainfall in inches at Moore Haven and LaBelle, 1935-56 __ 11 3 Geologic formations in Glades and Hendry counties 13 4 Water-level and flow measurements made during drilling of well 22, Glades County 36 5 Coefficients of transmissibility, storage and leakage in Glades, Hendry and eastern Collier counties 54 6 Analyses of water from wells in Glades and Hendry counties 60 7 Partial analyses of water from wells in Glades and Hendry counties -- ~--_______ 63 8 Records of wells in Glades and Hendry counties 102 GEOLOGY AND GROUND-WATER RESOURCES OF GLADES AND HENDRY COUNTIES, FLORIDA By Howard Klein, M. C. Schroeder, and W. F. Lichtler ABSTRACT Ground water in Glades and Hendry counties is obtained from the Floridan aquifer, which yields water by artesian flow in most areas of the two counties, and from several shallow aquifers. Highly permeable parts of the Floridan aquifer are limestones of the Tampa Formation' (early Miocene) and of the Ocala Group and the Avon Park Limestone (Eocene). The yields of wells pene- trating the Floridan aquifer usually exceed 200 gpm (gallons per minute). Except in the central and northwestern parts of Glades County, wells deeper than 800 feet yield highly mineralized water. The upper part of the Floridan aquifer (Tampa and Hawthorn Formations) yields relatively fresh water in the vicinity of LaBelle, Hendry County, and in all of Glades County except in the area adjacent to Lake Okeechobee. In the remainder of Hendry County, the artesian water contains more than 700 ppm (parts per million) of chloride. The artesian aquifer in Glades and Hendry counties is recharged primarily from the piezometric high in Polk County in central Florida. The piezometric surface of the aquifer is highest in north- western Glades County and southeastern Hendry County. The high-pressure area in southeastern Hendry County may be a residual mound resulting from a large number of uncontrolled flowing wells to the northwest. This uncontrolled discharge over a long period has resulted in an overall decline in artesian pressure in the counties. Discharge from the aquifer is mainly through flowing wells. 'The nomenclature of the rock units conform to the usages of the Florida Geological Survey and also, except for the Tampa Formation and the Ocala Group and its subdivisions, with those of the U. S. Geological Survey which regards the Tampa as the Tampa Limestone and the Ocala Group as two formations-the Ocala Limestone and the Inglis Limestone. The Ocala Group as used by the Florida Geological Survey includes the Crystal River, Williston, and Inglis Formations. FLORIDA GEOLOGICAL SURVEY Shallow ground water is obtained from wells ranging in depth from 20 to 300 feet, which penetrate limestone and shell beds in the Tamiami Formation (upper Miocene) and limestone and pebble beds in the upper part of the Hawthorn Formation. The quality of the water from these aquifers generally is superior to that from the Floridan aquifer. Yields of 6-inch wells tapping shallow aquifers range from about 200 to 1,400 gpm. The most prolific shallow aquifer is a highly permeable limestone section of the Tamiami Formation which underlies central and southern Hendry County. Recharge to shallow aquifers is by local rainfall, by downward seep- age from overlying sediments, and by southward underflow from Highlands County, where pebble beds and limestone of the Hawthorn Formation occur at shallow depth. Discharge from the shallow aquifers is chiefly by evapotranspiration and by pumping for irrigation of truck crops. Quantitative tests on wells penetrating the shallow aquifers show that the coefficient of transmissibility ranges from 70,000 gpd ft (gallons per day per foot) to 1,070,000 gpd/ft, and that the coefficient of storage ranges from 0.00015 to 0.0014. A method for forecasting the results of continued pumping during an extensive drought is illustrated in the report. INTRODUCTION PURPOSE AND SCOPE OF INVESTIGATION The extensive and expanding utilization of ground water for domestic, municipal, and irrigation supplies in Glades and Hendry counties, Florida, has created the problem of locating and preserving satisfactory water supplies. The expansion of agriculture increases the demand for irrigation water, a large part of which must come from ground-water reservoirs. The development and growth of communities are in part dependent upon the availability of adequate supplies of potable water. This report describes the geology and appraises the ground-water resources of Glades and Hendry counties. It contains information on the location, availability, and quality of the ground-water resources in the two counties, and furnishes basic data that can be used in flood control and water conservation. Fieldwork for the investigation was begun late in 1952 by the U. S. Geological Survey in cooperation with the Florida Geological Survey and the Central and Southern Florida Flood Control District, REPORT OF INVESTIGATIONS No. 37 but was suspended between 1953 and 1958 because of more urgent commitments. Work was resumed in June 1958 and was completed by September 1958. The investigation was under the supervision of N. D. Hoy, district geologist, and M. I. Rorabaugh, district engineer, of the U. S. Geological Survey. ACKNOWLEDGMENTS The investigation was aided by data contributed by local resi- dents, property owners, farmers, and ranchers. These data in- cluded the locations of wells, their total depth, casing depth, and yield, and in a few cases information on the quality of the water. The generosity of local residents in permitting the sampling of wells and measuring of water levels is greatly appreciated. The writers are especially indebted to the following well drillers and concerns: Roy Messer, LaBelle; Chester Beeles and James Drawdy, Arcadia; C. D. Cannon, Palmetto; the B. & D. Drilling Co., and James Whatley of Immokalee; and Miller Bros., Fort Myers. They granted permission to collect rock cuttings and water samples, take flow readings, and measure water levels during the drilling of wells and, in addition, they furnished geologic and hydrologic informa- tion. Flow-velocity measurements in flowing artesian wells were made through the cooperation of C. C. Carlton, Arcadia, and M. K. Wheeler, LaBelle. The Florida Geological Survey furnished logs of a few shallow and deep wells in the area. The Corps of Engineers, U. S. Army, Jacksonville District, furnished charts of water stages of the Caloosahatchee River. Mollusks listed in the well logs were identified by Julia Gardner and F. S. MacNeil of the Paleontology and Stratigraphy Branch, U. S. Geological Survey, Washington, and by personnel of the Florida Geological Survey, Tallahassee. PREVIOUS INVESTIGATION References to the geology and ground-water resources of Glades and Hendry counties have been made in several reports published by the Florida Geological Survey and the U. S. Geological Survey. Brief descriptions of surface and subsurface geology and water- well data in the Glades-Hendry area were presented by Matson and Clapp (1909), Sellards (1912, 1919), Matson and Sanford (1913), and Cooke and Mossom (1929). Stringfield (1936) discussed the FLORIDA GEOLOGICAL SURVEY geology and hydrology of the principal artesian aquifer in Florida. Cooke (1945) and Parker and Cooke (1944) discussed the surface and shallow subsurface geology in the Caloosahatchee River and Lake Okeechobee areas. Water-quality and water-level data were given by Stringfield (1936), and the chemical analyses of 17 ground-water samples were published by Black and Brown (1951). Schroeder and Klein (1954) described and interpreted the shallow geology of eastern Hendry County from a series of core borings. Parker and others (1955) gave generalized information on the geology of Glades and Hendry counties and presented a few specific data concerning the quality of the water from the Floridan aquifer and the shallow aquifers. DuBar (1958) described in detail the geology along the Caloosahatchee River and discussed the strati- graphic relationship of the Caloosahatchee Marl and the Fort Figure 1. Location of Glades and Hendry counties. REPORT OF INVESTIGATIONS No. 37 Thompson Formation. The following U. S. Geological Survey Water- Supply Papers contain records of ground-water levels in Hendry County: 987, 1017, 1024, 1072, 1097, 1127, 1157, 1166, 1192, 1222, 1266, 1322, and 1405. GEOGRAPHY LOCATION OF AREA Glades and Hendry counties are in the central part of southern Florida and constitute an area of approximately 2,000 square miles. Glades County, the smaller, lies north of Hendry County and borders the western shore of Lake Okeechobee (fig. 1). GENERAL LAND FEATURES AND DRAINAGE Three general physiographic units are included in Glades and Hendry counties and are classified with respect to land-surface altitude, surface-mantling material, and types of vegetation. The general units listed by Parker and Cooke (1944, p. 38-53) are the Everglades, the Sandy Flatlands, and the Big Cypress Swamp (fig. 2). Davis (1943, p. 40-50) subdivided the Sandy Flatlands and used the designation Western Flatlands for the area west of Lake Okeechobee. Also, he specifically designated the area in north- Seastern Glades County as the Istokpoga-Indian Prairie Basin. This unit extends northwestward into Highlands County. EVERGLADES The Everglades covers an area along the eastern boundary of Hendry County and reaches a maximum width of about 6 miles in the northeastern part of the county (fig. 2). In Glades County the Everglades borders part of the southwestern shore of Lake Okeechobee and extends to Lake Hicpochee. The boundary between the Everglades and other physiographic units is indefinite, but may be placed where sedges and sawgrass give way to true grasses, pinelands, and cypress trees. Places of slightly higher altitude support the growth of trees and shrubs because of better aeration of the soil. The soil of the Everglades is predominantly organic, but it contains some fine sand. The .organic soil is composed almost en- tirely of peat in eastern Hendry County, where the maximum thick- ness is 8 feet. Farther north, in southeastern Glades County, the FLORIDA GEOLOGICAL SURVEY HIGHLANDS COUNTY LAKE COLLIER COUNTY EXPLANATION SANDY FLATLANDS EVERGLADES BIG CYPRESS SWAMP APPROXIMATE DRAINAGE DIVIDE DIRECTION OF SURFICIAL DRAINAGE SCALE IN MILES 2 0 2 4 6 8 10 COLLIER COUNTY 81Oo' Figure 2. Glades and Hendry counties showing physiographic regions and the directions of surface drainage. REPORT OF INVESTIGATIONS NO. 37 sand content gradually increases until the soil loses its organic character. In eastern Hendry County the Everglades peat and muck overlies marl or an eroded marly limestone surface (Parker and Cooke, 1944, p. 48) at an altitude of about 8 feet above msl (mean sea level). The surface altitude of the Everglades is everywhere less than 25 feet above msl. SANDY FLATLANDS The Sandy Flatlands is the largest physiographic unit in Glades and Hendry counties. In Glades County it includes all but the area east of Lake Hicpochee, and in Hendry County all but the eastern and southern edges (fig. 2). The Sandy Flatlands extends north- ward into Highlands County, westward to the Gulf of Mexico and southward into Collier County. A minor subdivision in northeastern Glades County is the southward extension of the Istokpoga-Indian Prairie Basin. The sands were deposited as marine terraces during late Pleistocene time, when sea level fluctuated from more than 70 feet to less than 25 feet above sea level. The surface altitude in the Sandy Flatlands ranges from about 10 feet to more than 70 feet above msl. The highest sandy surfaces, which are in western Glades County and north of Fisheating Creek, were deposited by the Penholoway sea of Pleistocene time, which stood 42 feet to more than 70 feet above present sea level. The wide reentrant in the Penholoway terrace in the northwestern part of Glades County (fig. 3) resulted from erosion by Fisheating Creek after the recession of the Penholoway sea. Figure 3 (from Parker and others, 1955, pl. 10) shows the approximate extent of Pleisto- cene terrace surfaces in Glades and Hendry counties. The Talbot terrace slopes gently toward the Caloosahatchee River and Lake Okeechobee and surface altitudes range from about 42 to 30 feet above msl (fig. 3). An area in western Hendry County, where altitudes are comparable to the Talbot terrace, was referred to by Parker (1955, p. 139) as Immokalee Island. The Pamlico terrace, where altitudes do not exceed 30 feet above msl, is the area between the Talbot terrace and the Everglades. BIG CYPRESS SWAMP The Big Cypress Swamp includes a large part of southern Hendry County. The land-surface altitude in this area is lower than that of the Sandy Flatlands, but is usually slightly higher than FLORIDA GEOLOGICAL SURVEY LAKE OKEECHOBEE Figure 3. Approximate extent of Pleistocene terraces in Glades and Hendry counties. EXPLANATION PENHOLOWAY TERRACE fmn TALBOT TERRACE PAMLICO TERRACE REPORT OF INVESTIGATIONS No. 37 the Everglades. Except in small areas of southwestern Hendry County, altitudes are less than 25 feet above msl. The soil of the Big Cypress Swamp in Hendry County is chiefly sand grading to loam near the northern boundary of Collier County. At the edges of the Big Cypress Swamp the soils merge with the sand of the higher Sandy Flatlands and the peat and muck of the Everglades. The surface of the Big Cypress Swamp is flat and marked by many small, high hammock areas. The hammocks support bunch grass, palmettos, and pines, and stand out from the swampy region where low cypress, sedges, and marsh plants predominate. DRAINAGE Most of Glades and Hendry counties lie within the Fisheating Creek and the Caloosahatchee River watersheds. These and other drainage features are shown in figure 2. Drainage of the northern part of Glades County is by Fisheating Creek, which flows south- ward from the high sandy ridge areas of Highlands County into Glades County and eastward into Lake Okeechobee. Because of the low gradient in the eastern reaches of Fisheating Creek, drainage is sluggish and much of this area in eastern Glades County is flooded during rainy seasons. The northeastern part of the county is drained chiefly by the Kissimmee River, the Harney Pond Canal, and the Indian Prairie Canal. Drainage in the remainder of Glades County and the western part of Hendry County is by the Caloosa- hatchee River. The divide that separates the Caloosahatchee River and the Fisheating Creek drainage basins trends east-southeast across south-central Glades County. The Devil's Garden marshy area in central and southern Hendry County drains sluggishly to the west into the Okaloacoochee Slough, which in turn normally drains northward into the lower Sandy Flatlands, and southward into the Big Cypress Swamp. During high-water periods, drainage from Devil's Garden may occur in all directions. The discharge of the Caloosahatchee River depends upon the water stage of Lake Okeechobee. During low lake stages the spillways and gates at Ortona Lock are closed and flow in the river is greatly reduced. However, during wet periods the gates are opened and the discharge of the river is increased many times. The stage of the Caloosahatchee River is affected by the Gulf of Mexico tides as far upstream as the Ortona Lock. Before drainage and water control were in effect in the Ever- glades and Lake Okeechobee areas, the Lake Flirt basin and Lake FLORIDA GEOLOGICAL SURVEY Hicpochee were fed by overflow from Lake Okeechobee. Much of the Everglades and the areas adjacent to Lake Okeechobee and the Caloosahatchee River were flooded during rainy seasons and for a considerable period afterward. The construction of the levee along the southern rim of Lake Okeechobee and the improvement of the channel of the Caloosahatchee River after the floods of 1928 resulted in a decrease in the overall area affected by periodic flooding. The Devil's Garden and the Okaloacoochee Slough in central and western Hendry County are the largest remaining marshy areas (fig. 2). Surface runoff throughout most of the 2-county area is sluggish because of the flatness of the region. Rainfall soaks into the sandy mantle of the flatlands, and when the ground becomes saturated, wide shallow ponds and marshes form in large areas. CLIMATE The climate of Glades and Hendry counties is subtropical and the temperature rarely falls below freezing. Table 1 shows the average monthly and yearly temperatures at Moore Haven and La Belle. Table 2 shows the maximum, minimum, and average monthly and yearly rainfall at the same stations. The average annual rainfall for the period 1935-56, from U. S. Weather Bureau records, is 49.83 inches at Moore Haven and 51.81 inches at LaBelle. The maximum monthly rainfall at Moore Haven was 21.55 inches in September 1948. The minimum of record occurred in 1956 when only 30.94 inches of rain fell at Moore Haven. Rainfall is heaviest during June through October and lightest during November through February. The average monthly rainfall at the Moore Haven and LaBelle stations is similar. TABLE 1. Average Temperature (oF) at Moore Haven and LaBelle, 1935-56 Moore Haven LaBelle January 64.00 64.2 February 64.5 64.4 March 67.5 68.0 April 72.0 72.5 May 75.9 76.5 June 79.5 79.9 July 80.9 81.3 August 81.4 81.7 September 80.3 80.6 October 75.9 75.6 November 68.9 68.5 December 67.4 65.1 Year 73.2 73.2 REPORT OF INVESTIGATIONS NO. 37 TABLE 2. Rainfall, in Inches, at Moore Haven and LaBelle, 1935-56 Moore Haven LaBelle Max. Min. Average Max. Min. Average January 5.73 0.05 1.45 4.07 0.00 1.48 February 5.02 .03 1.68 5.46 .03 1.84 March 8.73 .03 2.17 8.84 .01 2.35 April 5.64 .21 3.03 7.71 .65 3.05 May 11.96 1.13 4.39 9.24 .71 3.12 June 15.02 3.61 7.25 19.32 3.33 9.20 July 16.13 2.99 8.27 15.14 5.11 8.46 August 12.51 2.39 6.61 13.90 2.21 7.66 September 21.55 2.23 8.08 18.51 2.92 7.87 October 11.11 .03 4.17 13.46 .31 4.21 November 5.47 .03 1.31 2.21 .18 1.26 December 6.46 .11 1.42 4.63 .08 1.31 Year 71.20 30.94 49.83 73.83 36.83 51.81 DEVELOPMENT AND GROWTH OF AREA In 1950 the populations of Glades and Hendry counties were 2,199 and 6,051, respectively. Between 1940 and 1950 the popula- tion of Glades County declined about 20 percent and that of Hendry County increased more than 10 percent. The estimated populations as of July 1958 were 3,100 for Glades County and 7,200 for Hendry County. Most of the population is concentrated near Lake Okeechobee. In 1950, Moore Haven, the Glades County seat, LaBelle, the Hendry County seat, and Clewiston, had populations of 636, 945, and 2,499, respectively. The population of the area increases in winter when migrant farmworkers move into the area for the growing season. Only a small number of tourists visit these two counties, mainly for fishing in Lake Okeechobee and hunting. Agriculture is the predominant economic activity in both counties, and the chief products are winter vegetables, sugarcane, beef cattle, and dairy products. Green beans, lettuce, and sugarcane are grown on the Everglades mucklands adjacent to Lake Okeechobee; peppers, tomatoes, cucumbers, and watermelons are the main crops raised on the sandy soils. A crop is grown every year on the mucklands, but on the sandy soils the land is farmed for only one or two seasons, owing to the spread of plant disease and the rapid growth of Bermuda grass on the cultivated soil. The land then usually is converted to improved pasture with a forage cover of pangolia, carib, or other grass. Citrus is grown along the Caloosahatchee River downstream from LaBelle. Dairy farms are located near Clewiston, LaBelle, Moore Haven, and Lakeport. One of the largest single-unit cane factories for producing raw sugar is located south of Clewiston. FLORIDA GEOLOGICAL SURVEY GEOLOGIC FORMATIONS AND WATER-BEARING CHARACTERISTICS The main water-bearing rocks underlying Glades and Hendry counties include consolidated and unconsolidated strata ranging in age from Eocene to Recent. Rocks of middle Miocene age and older yield water by natural flow, but the shallower, younger sedi- ments yield water to wells in which the water levels normally are below the land surface. The sediments form part of the southern flank of the regional Ocala uplift (Vernon, 1951, p. 54-65), the crest of which is in northern and north-central Florida. The beds conform to the regional uplift in a subdued manner and dip gently to the south. The general sequence of geologic formations under- lying Glades and Hendry counties is shown in table 3. Rocks deposited before the middle Miocene Epoch are composed almost entirely of limestone, formed by the accumulation and cementation of shell fragments and by chemical precipitation of calcium carbonate in a marine environment. Younger materials are chiefly plastics, deposited as an aggregate of sand, silt, and clay, with shelly material scattered throughout. The surface sediments in Glades and Hendry counties are of Pleistocene and Recent age. Subsurface beds composed of im- permeable clay and marl form a major part of the middle Miocene. A limestone section occurs at the top of the Tampa Formation and continues downward through Oligocene, Eocene, and Paleocene rocks. According to Applin (1951, p. 6-7) the top of the Upper Cretaceous rocks in Glades and Hendry counties occurs at depths ranging from 4,500 to 6,000 feet. Oil is recovered from Lower Cretaceous rocks at the Sunniland field (Collier County), near the southwest corner of Hendry County, from a depth of about 11,500 feet. The recognition and differentiation of the Tertiary formations are of variable accuracy. In most samples macrofossils are not present in sufficient quantities to make accurate determination of the formation. In many cases no diagnostic fossils were present in the drill cuttings, and lithologic differences were used to identify the formations. EOCENE SERIES Rocks of the Eocene Series in Glades and Hendry counties are chiefly limestones of different textures and permeability, and are represented in ascending order by the Oldsmar Limestone, the Lake TABLE 3. Geologic Formations in Glades and Hendry Counties Estimated range of thickness Series Group Formationi (feet) Lithology and water-bearing properties Recent Organic soils 0- 8 Peat and muck; water has high color. Lake Flirt Marl 0- 8 Fresh-water marl, sandy muck, carbonaceous sand; of low permeability. Terrace deposits 0- 15 Quartz sand; yields small quantities of water to sandpoint wells; water is colored and high in iron content. Pleistocene Fort Thompson Formation 0- 15 Alternating marine shell beds and fresh-water marl; generally of low (contemporaneous with permeability except locally where it is solution riddled. Anastasia) Anastasia Formation 0- 15 Sand, marl, and shell beds; yields colored water to standpoint wells. Pliocene Caloosahatchee Marl 0- 60 Shell, sand, and silt; shell beds yield water that in some areas is highly mineralized. Tamiami Formation 30-110 Sand, marl, shell beds, and limestone; limestone is fairly widespread and yields large quantities of water for irrigation. Hawthorn Formation 300-500 Clay marl, sand, gravel, and limestone; clay marl forms confining beds Miocene for the Floridan aquifer; limestone at base forms upper part of the Floridan aquifer; sand and gravel and limestone beds in upper part yield water to wells. Tampa Formation 15-100 Sandy limestone: yields water under artesian pressure; is part of the Floridan aquifer. Oligocene Suwannee Limestone 0-570 Ocala 150-800 Limestone and dolomite; yields water under artesian pressure, in many areas highly mineralized; is part of the Floridan aquifer. Eocene Avon Park Limestone 200-390 Limestone and dolomite; yields water under artesian pressure, highly mineralized in much of the area; is part of the Floridan aquifer. Lake City Limestone 800+ Crystalline dolomite, dolomitic limestone and chalky limestone; porous and highly permeable; yields large quantities of highly mineralized water in much of the area; is part of the Floridan aquifer. 1U. S. Geological Survey lists formations as follows: Luke Flirt Marl as Pleistocene and Recent; Ocala Group as Ocala Limestone and Inglis Lime- stone; Tampa Formation as Tampa Limestone. 0 *U FLORIDA GEOLOGICAL SURVEY City Limestone, the Avon Park Limestone, and limestones of the Ocala Group. The Oldsmar Limestone, the oldest formation of the series, has not been penetrated by water wells in the two counties. Cooke (1945, p. 40) states that the formation unconformably over- lies rocks of Paleocene age. In most places in Florida the formations of the Eocene Series can be differentiated only by a study of micro- fossils. Figure 4 shows the locations of wells for which detailed logs are available and also the locations of the geologic sections shown in figures 5-8. LAKE CITY LIMESTONE The Lake City Limestone is the name applied by Applin and Applin (1944, p. 1693) to the dark-brown chalky limestone of early middle Eocene age penetrated between depths of 497 to 1,010 feet in a well at Lake City, Columbia County. They give a thickness of 200 to 250 feet for the formation in peninsular Florida, and Cooke (1945, p. 46) also estimates that the formation in southern Florida ranges in thickness from 200 to 250 feet. The Lake City Limestone beneath southern Florida is composed of brown, hard, crystalline dolomite and dolomitic limestone, and cream-colored permeable limestone. The general absence of appreciable plastic material and the subsurface extent of the limestone indicates that Glades and Hendry counties were located a considerable distance offshore at the time of its deposition. A large part of the fossil content of the Lake City Limestone is Foraminifera. Applin and Jordan (1945, p. 131) list species that they consider diagnostic of the formation. Vernon (1951, p. 92) indicates that the Lake City Limestone may rest unconformably on the Oldsmar Limestone and is unconformable with the overlying Avon Park Limestone. Bishop (1956, p. 113) estimates that 80 feet of the Lake City Limestone was penetrated in well 22, in northeastern Glades County (fig. 5). The only other known penetrations of this formation were by deep oil-test wells. The geologic section A-A' shown in figure 5 indicates that the regional dip of the formation is southward. The Lake City Limestone has good porosity, is highly permeable, and is part of the Floridan aquifer. Bishop (1956, p. 18) states that the Lake City Limestone, because of its high permeability, is a highly productive part of the Floridan aquifer beneath Highlands County. However, it yields highly mineralized water in most of Glades and Hendry counties. REPORT OF INVESTIGATIONS NO. 37 Figure 4. Glades and Hendry counties showing locations of geologic sections and included wells. FLORIDA GEOLOGICAL SURVEY Figure 5. South-north geologic section A-A' through Glades and Hendry counties. AVON PARK LIMESTONE Applin and Applin (1944, p. 1686-1687) gave the name Avon Park Limestone to the highly microfossiliferous limestone in the upper part of the late middle Eocene rocks which occur between depths of 600 and 930 feet in a well drilled at Avon Park in Polk County. Vernon (1951, p. 95-96) identified the Avon Park Lime- stone at the surface in Citrus and Levy counties. The formation underlies all of Glades and Hendry counties, increasing in thickness to the southeast; it ranges from 200 feet in southern Highlands County (Bishop, 1956, p. 14) to 390 feet in southern Hendry County. The Avon Park Limestone is mainly a tan-to-white, slightly porous, chalky limestone containing many microfossils; part of the formation, however, is composed of brown, hard, granular limestone and dolomitic limestone. The microfossils have been described by Applin and Applin (1944), Applin and Jordan (1945), and Cole (1942, 1944). Vernon (1951, p. 99) indicates that the Avon Park Limestone is separated from older and younger formations by erosional unconformities. Cooke (1945, p. 51-52) states, "The Avon Park limestone was deposited in an open ocean that received little sand or clay. The REPORT OF INVESTIGATIONS No. 37 17 B R HENDRY COUNTY I GLADES COUNTY D o(- t B- B a 200 M M W 200 aj _j J 0 MSL ML SMSL TAMIAM FORMAT -f----f..-- MSLO -200 HAWTHORN FORMATION -200 .400 TA--PA--.F -400 TAMPA FORMATION -600 -600 SUWANNEE LIMESTONE --8oo00 -8oo -1000 -I00& OCALA GROUP -1200 -1200 -1400 AVON PARK LIMESTONE -1400 -1600 -- -1600 -- FORMATION CONTACTS DASHED ST WHEREINFERRED S LAKE CITY LIMESTONE SCALE IN MILES 2 0 2 4 6 a Figure 6. South-north geologic section B-B' through Glades and Hendry counties. entire Floridan Plateau was probably submerged, but the location of the shore line is unknown." Vernon (1951, p. 97) states, "The fauna of the Avon Park limestone ranges from a shallow-water marine beach to only slightly deeper marine facies. The environ- ments favorable for such deposits are shallow coastal bays, beaches, and marine shelves where almost no plastic material was being deposited." Vernon found in Polk County that the Avin Park Limestone resembled a beach-type deposit, and in -the:-: encircling area the limestone is a shallow-water marine deposit. It seems likely that in Glades and Hendry counties the Avon Park Limestone is mainly a shallow-water marine-shelf deposit. The formation is an important component of the Floridan aquifer and will yield water to flowing wells in most areas. In much of Glades and Hendry counties the water is highly mineralized. FLORIDA GEOLOGICAL SURVEY C 200 < 0MSL -200 -400 -600 -800 -1000 -1200 -1400 -1600 TAMPA FORMATION -600 -600 HENDRY COUNTY -- TAMIAMI lIOCENE __ _-_ TIAMI FORMATION HAWTHORN FORMATION C' 200 MSLO -200 -400 -600 -800 -1000 -1200 SUWANNEE LIMESTONE OGALA GROUP AVON PARK - LIMESTONE FORMATION CONTACTS DASHED WHERE INFERRED SCALE IN MILES U 468 -1400 Figure 7. West-east geologic section C-C' through Hendry County. OCALA GROUP Cooke (1915, p. 117; 1945, p. 53) defined the Ocala as limestone of Jackson age. Applin and Applin (1944, p. 1683-1685) and Applin and Jordan (1945, p. 130) determined that the Ocala could be differentiated into a lower and an upper unit. Vernon (1951, p. 115) correlated the basal 80 feet of the Ocala Limestone of Cooke (1945, p. 53-73) at the outcrop area in Citrus and Levy counties with the Moodys Branch Formation of early Jackson age in Alabama. By separating this basal part, to which he applied the name Moodys Branch Formation, Vernon (1951, p. 156) restricted the Ocala Limestone to beds of late Jackson age. He described the Moodys Branch Formation in Florida as a marine, fossiliferous limestone REPORT OF INVESTIGATIONS NO. 37 Figure 8. South-north geologic section D-D' along the western shore of Lake Okeechobee. composed of the camerinid-rich Williston Member at the top, and the echinoid-rich Inglis Member at the base. The Ocala Limestone of Cooke was raised to group rank by Puri (1953, p. 130), who subdivided it into three formations as follows: the Crystal River Formation, equivalent to Vernon's Ocala Limestone (restricted); the Williston Formation, equivalent to the upper part of the Moodys Branch Formation; and the Inglis Formation, equivalent to the lower part of the Moodys Branch Formation. Limestones of the Ocala Group range in thickness from about 150 feet to 390 feet and appear to thicken in a southwesterly direction within Glades and Hendry counties. In general they are cream-colored, soft and chalky, and in many places are composed of a foraminiferal coquina. The lowermost part of the Ocala Group is unconformable with the Avon Park Limestone. The top of the Ocala is an eroded surface and, according to Cooke (1945, p:' 56)4, the oldest outcropping rocks overlying it are those of the Mariannai Limestone of middle Oligocene age in northwestern Florida. Cooke (1945, p. 57) suggests that during the deposition of the Ocala Group the shoreline was in Alabama and Georgia and that the sea was open and fairly shallow. Vernon (1951, p. 57) seems to agree with this concept, as he found some detrital, crossbedded limestone in his Inglis Member. FLORIDA GEOLOGICAL SURVEY Bishop (1956, p. 23) states that the limestones of the Ocala Group are not important units in the Floridan aquifer beneath the ridge area of Highlands County. In Glades and Hendry counties, however, they are fairly permeable and yield appreciable amounts of water to wells penetrating the aquifer. These lime- stones contain relatively salty water in most parts of the two counties. OLIGOCENE SERIES Cooke (1945, p. 75) states, "The Oligocene series, as interpreted by the United States Geological Survey, is divided into three parts. The lowest, which includes the Red Bluff clay and the Forest Hill sand of Mississippi, is not known to be represented in Florida. The Marianna limestone and the overlying Byram limestone together comprise the middle part to which the name Vicksburg group is now restricted. The Suwannee limestone and its littoral equivalent, the Flint River formation, are of late Oligocene age." The Suwannee Limestone apparently is the only formation of Oligocene age in Glades and Hendry counties. SUWANNEE LIMESTONE The name Suwannee Limestone was proposed by Cooke and Mansfield (1936, p. 71) for the yellowish limestone exposed along the Suwannee River in Hamilton and Suwannee counties, in northern Florida. The formation includes all the beds lying below the Tampa Formation and above the Byram Formation or older beds. The definition is the same as that used by MacNeil (1944, p. 1313-1318). The Suwannee Limestone underlies all of Glades and Hendry counties except an area in the northeastern part of Glades County. The formation thickens from north to south and apparently from east to west, and reaches a maximum thickness of about 570 feet (fig. 5-7). The distribution of Oligocene rocks in Florida indicates that erosion prevailed over large areas during the Oligocene Epoch. The sea that transgressed during the middle Oligocene Epoch deposited the Marianna and Byram Formations in western Florida, but Glades and Hendry counties probably were above sea level during early and middle Oligocene time and limestone of the Ocala Group was undergoing considerable erosion. It appears that the only time Glades and Hendry counties were covered by Oligocene seas was during deposition of the Suwannee Limestone. REPORT OF INVESTIGATIONS NO. 37 The Suwannee Limestone is a white, finely porous limestone, somewhat crystalline and partly dolomitized. It is moderately permeable and yields artesian water to deep wells that penetrate the Floridan aquifer; however, the water contained in the Suwannee Limestone is brackish in most of Glades and Hendry counties. MIOCENE SERIES Cooke (1945, p. 109-111) recognized three divisions of the Miocene which, in the Florida Peninsula, are represented by the Tampa Formation (lower Miocene), Hawthorn Formation (middle Miocene), and Duplin Marl. Puri (1953, p. 38-41) recognized three divisions of the Miocene in the Florida Panhandle: Tampa Stage (lower Miocene), the Alum Bluff Stage (middle Miocene), and the Choctawhatchee Stage (upper Miocene). In southern Florida the Miocene Series is represented by the Tampa Formation, the Haw- thorn Formation, and the Tamiami Formation in ascending order. TAMPA FORMATION The Tampa Formation of this report refers to the sandy lime- stone, of Miocene age, that lies above the Suwannee Limestone and beneath the predominantly plastic beds of the Hawthorn Formation. The Tampa Formation, which crops out in the vicinity of Tampa Bay, was originally described by Johnson (1888) and Dall (1892). The formation probably underlies all of Glades and Hendry counties, but in northeastern Glades County it is very thin. It gradually increases in thickness from 15 feet in northeastern Glades County to about 190 feet in southern Hendry County. It is composed of porous, highly permeable limestone, friable calcareous sandstone, and a few beds of white chalky marl. Because of solution by ground-water movement, fossils are preserved mainly as molds. This solvent action has produced the very porous and permeable zones within the formation. The Tampa Formation overlies the Suwannee Limestone unconformably. Puri (1953, p. 38) indicates that the Tampa is unconformably overlain by the Hawthorn Formation and its equivalents in western Florida. Some of the field studies of Cooke (1945, p. 115) suggest that it may grade vertically upward into the Hawthorn Formation. This gradational relationship may pertain in Glades and Hendry counties. The Tampa Formation is very permeable, and together with the limestones of the lower part of the Hawthorn Formation FLORIDA GEOLOGICAL SURVEY furnishes most of the artesian water used in Glades and Hendry counties. HAWTHORN FORMATION The Hawthorn Formation of this report is defined as beds younger than the Tampa Formation and older than the upper Miocene sediments. This is essentially the definition of Cooke (1945, p. 44) and of Vernon (1951, p. 186-187). The Hawthorn Formation underlies all of Glades and Hendry counties and ranges in thickness from about 300 feet in southern Hendry County to about 500 feet in northern Glades County. The Hawthorn Formation is composed of light-green to greenish- gray sandy marl, green and white plastic clay, finely crystalline permeable limestone, silty sands, and quartz pebbles. These sediments commonly contain small grains of phosphorite and occasionally contain phosphate pebbles. The coarse sand and pebbles occur in the beds near the top of the formation and the limestone beds usually occur near the base. Sandy and clayey marls are the predominant sediments of the Hawthorn Formation. Puri (1953, p. 38-39) had indicated that in western Florida the Hawthorn Formation and its equivalents overlie the Tampa Forma- tion unconformably and underlie the upper Miocene sediments unconformably. Cooke (1945, p. 145) also reports that the upper Miocene beds overlie the Hawthorn plastics unconformably. Lithologic and foraminiferal studies of cuttings from wells located west and southeast of Glades and Hendry counties suggest that the Tamiami Formation (upper Miocene) may overlie the Hawthorn Formation conformably. The Hawthorn Formation probably is early and middle Miocene in age. The Hawthorn Formation, as examined from well cuttings in Glades and Hendry counties, is apparently of marine origin. Bishop (1956, p. 26) has found that the ridge area in Highlands County is underlain by deltaic sediments containing sand, quartz pebbles, phosphorite, mica, and kaolinite, which overlie typical marine marl and clay of the Hawthorn Formation. The upper Miocene beds appear to wedge out against these deltaic deposits on both flanks of the ridge. The deposits probably are of late Hawthorn age and apparently extend southward into Glades County in the vicinity of U. S. Highway 27. According to reports from well drillers, a gravelly bed occurs in northeastern Glades County and extends southward into Hendry County. It has been recognized in some of the wells for which lithologic logs have been prepared. In well 4, west of Clewiston in REPORT OF INVESTIGATIONS NO. 37 Hendry County, the gravel between 91 and 127 feet below the land surface could be interpreted as the basal part of the Tamiami Formation; however, the authors believe that it is part of the Hawthorn Formation and is a southward extension of the ridge deltaic deposits. Quartz pebbles also have been penetrated within the Hawthorn Formation in a well on Marco Island, Collier County, a well in Dade County near the Collier-Monroe County line, and a well on Cape Sable in the Everglades National Park. Bishop (1956, p. 27) also reports that quartz pebbles have been found in the Hawthorn Formation- underlying the Bone Valley Formation (Pliocene) in Polk County. Well drillers report that in Glades and Hendry counties the gravels are usually isolated masses and are of irregular thickness. These occurrences tend to substantiate the fact that a delta tongue extended southward from Highlands County during late Hawthorn time. Glades and Hendry counties were submerged during early Hawthorn time and the shoreline probably extended as far north as the Ocala uplift, as suggested by Vernon (1951, p. 181-184). Before the end of Hawthorn time a finger of a delta progressed southward across Highlands County and the final frontal slope formed near Venus (Highlands County). It is presumed that only bottomset deltaic beds were deposited in Glades and Hendry counties. The sea withdrew from most of Florida at the end of Hawthorn time, but there is a possibility that all of southern Florida may have been receiving continuous deposition during the middle and late Miocene time, and the contact between the Haw- thorn Formation and the Tamiami Formation may be conformable. Local occurrences of gravel, thin limestone beds, and shell beds in the upper part of the Hawthorn Formation form moderately productive aquifers in an area about 5 miles west of Moore Haven in Glades County, in an area north of the Devil's Garden in Hendry County, and in the vicinity of LaBelle. Wells that penetrate these aquifers range in depth from about 100 to 175 feet. The limestone beds in the lower part of the Hawthorn Forma- tion are fairly widespread and may form a hydrologic unit with the underlying more permeable limestones of the Floridan aquifer. The beds by themselves do not yield sufficient quantities of water for most irrigation needs, and wells are generally drilled into one or more of the underlying limestones. In most places, the clay and marl of the Hawthorn Formation form the confining unit for the Floridan aquifer; upward leakage through these materials is small. FLORIDA GEOLOGICAL SURVEY TAMIAMI FORMATION The Tamiami Formation, as redefined by Parker (1951, p. 823), includes all upper Miocene deposits in southern Florida. The Tamiami Formation underlies all of Glades and Hendry counties. The deposition of sediments in Glades and Hendry counties during Tamiami time probably was controlled by the southward extension of the Hawthorn deltaic plastic materials which formed a topographic high. In the western half of Glades and Hendry counties and in Lee and Charlotte counties .the Hawthorn deltaics occur at a higher altitude than the Hawthorn plastic sediments to the east (fig. 7). Consequently, the overlying sediments of Tamiami age in the western parts of the counties are thinner than those in the eastern parts of the counties and probably do not exceed 80 feet in thickness (fig. 7). They are composed chiefly of fine and medium sand, silt, marl, and lenses or thin beds of shells. These sediments appear to be reworked Hawthorn deltaic deposits. In much of the eastern part of Hendry County the Tamiami Formation contains limestone that dips to the east and southeast. Limestone in the Tamiami Formation is continuous and widespread over an area exceeding 400 square miles. At the Collier-Hendry County boundary, directly east of Immokalee, limestone occurs at a depth of 22 feet below the land surface and extends to a depth of at least 55 feet. This limestone layer presumably dips eastward to a depth of about 90 feet in an area 8 miles east of the county boundary, and to a depth of 120 feet in an area about 20 miles east of the county line. The limestone wedges out 3 to 5 miles east of Immokalee, and no shallow limestone beds are reported in the immediate vicinity of Immokalee. The Tamiami Formation differs in composition from shelly marl to soft, silty, fossiliferous limestone in different localities. The formation crops out locally along the Caloosahatchee River in Glades and Hendry counties where it is a greenish-gray sandy clay. DuBar (1958, p. 34) suggests that the Tamiami Formation along the Caloosahatchee River reaches a maximum thickness of at least 60 feet. Throughout Glades County and northern and western Hendry County the Tamiami Formation is composed chiefly of sand, marl, and shells. In most of southern and eastern Hendry County the limestone beds of the Tamiami Formation are highly permeable and yield large quantities of water to relatively shallow irrigation wells. In the remainder of Hendry County and in Glades County local shell beds and lenses will yield moderate quantities of water to REPORT OF INVESTIGATIONS NO. 37 domestic wells or small irrigation wells. Some shell beds in the vicinity of LaBelle and the area bordering Lake Okeechobee yield water of relatively high mineral content. PLIOCENE SERIES The Caloosahatchee Marl is the only formation of Pliocene age recognized in southern Florida. Although there is some uncertainty about the age of the Caloosahatchee Marl, the authors tentatively are retaining it in the Pliocene. DuBar (1958, p. 35) assigned the Caloosahatchee Marl to the Pleistocene, primarily on the basis of vertebrate fossils, and to a lesser extent on mollusks and strati- graphic relationship. CALOOSAHATCHEE MARL The shell beds exposed along the upper reaches of the Caloosahatchee River were classified by Heilprin (1887) as Pliocene in age. Matson and Clapp (1909, p. 123) adopted the name Caloosahatchee Marl for these beds and their definition has been in general use since that time. The formation as used in this report comprises the sediments that contain a molluscan fauna considered as diagnostic of the Caloosahatchee Marl. The distribution and areal extent of the Caloosahatchee Marl are not well known. It is exposed along the Caloosahatchee River and has been penetrated in wells near the river and along the margin of Lake Okeechobee (fig. 8). Shelly material dredged from drainage canals a few miles southeast of Lake Okeechobee closely resembles the material along the Caloosahatchee River. DuBar (1958, p. 85, fig. 29) indicates that the Caloosahatchee Marl ranges in thickness from 5 to 25 feet in areas adjacent to the river and downstream from LaBelle. Upstream from LaBelle test wells penetrated 45 to 65 feet of the formation, but did not reach the bottom. Generally, the Caloosahatchee Marl ranges in thickness from 15 to 30 feet, although thicknesses of 60 feet have been noted. The formation appears to be a discontinuous deposit, occurring as erosional remnants filling depressions in the older eroded surface of the Tamiami Formation. The Caloosahatchee Marl consists predominantly of unconsoli- dated sand and sandy marl that contain abundant marine mollusks. In addition to the profusion of mollusks, one of the outstanding features of the formation along the banks of the Caloosahatchee River is a 2-foot layer of hard, solution-riddled marine limestone FLORIDA GEOLOGICAL SURVEY which Dubar (1958, p. 58) calls the Bee Branch Member. About 21' miles upstream from LaBelle the Bee Branch Member of DuBar dips beneath the waterline. Schroeder and Klein (1954, p. 5) indicate that in eastern Hendry County a greenish silty sand and sandy marl, derived from erosion of green clay marl of the Tamiami Formation, composed a part of the Caloosahatchee Marl. These greenish sediments appear to be restricted to the flanks of the hills of the eroded Tamiami Formation. In general, the Caloosahatchee Marl has low permeability and is a relatively unimportant source of ground water. Small yields can be obtained from shell beds and lenses, but in areas adjacent to the Caloosahatchee River where the Bee Branch Member of DuBar is best developed in the subsurface, the formation may yield fairly large quantities of water by infiltration from the river. In the area along the west shore of Lake Okeechobee the water is usually highly mineralized. PLEISTOCENE SERIES Formations of Pleistocene age in southern Florida are the sands of the marine terraces, the Anastasia and Fort Thompson Formations, the Key Largo Limestone, and the Miami Oolite. The higher terraces of early Pleistocene age, the Miami Oolite, and Key Largo Limestone do not occur in Glades and Hendry counties. The Anastasia Formation and the terrace sands are of marine origin and the Fort Thompson Formation is a succession of marine and fresh-water beds. The different elevations of the Pleistocene shorelines and the alternation of marine and fresh-water beds in the Fort Thompson Formation give a record of the oscillation of sea level during the ice age. Although the maximum advances of ice sheets were far to the north, their advances and retreats affected Florida by alternately lowering and raising the level of the sea as water was being frozen or melted and consequently was being withdrawn from or added to the ocean. The Pleistocene deposits in Glades and Hendry counties are chiefly quartz sands, shell beds, limestone, and marl. ANASTASIA FORMATION The Anastasia Formation was named by Sellards (1912) for outcrops of coquina on Anastasia Island, near St. Augustine, Florida. Cooke and Mossom (1929, p. 199) expanded this definition to include all the marine deposits of Pleistocene age underlying the REPORT OF INVESTIGATIONS No. 37 lowest plain bordering the east coast of Florida, excluding the Key Largo Limestone and Miami Oolite in southeastern Florida. Parker and Cooke (1944, p. 66) defined the formation as follows: "The Anastasia formation as here defined includes the coquina, sand, sandy limestone, and shelly marl of pre-Pamlico Pleistocene age that lies along both the Florida east and west coast." The exact distribution of the Anastasia Formation is not known. It probably is present beneath all of Glades and Hendry counties excluding the Everglades area in eastern Hendry County, a 5-mile strip on either side of the Caloosahatchee River, and a strip 5 to 10 miles wide along the west shore of Lake Okeechobee. The thickness of the formation is commonly about 2 to 3 feet and probably does not exceed 15 feet. The coquina limestone found at the type locality of the Anastasia Formation does not occur in Glades and Hendry counties. Sand, shell, and marl form most of the formation in Glades and Hendry counties. A thin marine sandstone is the most prominent bed in the formation. The beds in eastern Hendry County that have been assigned tentatively to the Fort Thompson Formation by Schroeder and Klein (1954, p. 5) are apparently transitional between the Fort Thompson and Anastasia Formations. The formation is overlain unconformably by the Pamlico Sand and underlain unconformably by the Caloosahatchee Marl. A few wells for domestic supplies and numerous wells for watering stock derive water from the Anastasia Formation. The water is generally colored and high in iron content. FORT THOMPSON FORMATION The alternating fresh-water and marine limestones exposed along the Caloosahatchee River at Fort Thompson, about 2 miles east of LaBelle, were initially named the Fort Thompson beds by Sellards (1919, p. 71-72). Cooke and Mossom (1929, p. 211-215) later named this sequence the Fort Thompson Formation and indicated that the beds lie unconformably on the Caloosahatchee Marl and are overlain by the Lake Flirt Marl of Recent age. The Fort Thompson Formation in Glades and Hendry counties has its maximum thickness in the southern part of the Everglades basin. It extends in a strip about 5 miles wide near the eastern border of Hendry County, in a strip about 5 miles on either side of the Caloosahatchee River upstream from LaBelle, and in a strip 5 to 10 miles wide along the west shore of Lake Okeechobee. The formation ranges in thickness from 2 to 15 feet. The typical development at old Fort Thompson shows alter- FLORIDA GEOLOGICAL SURVEY nating beds of marine shells and fresh-water limestones. The limestones apparently are case-hardened marl. The Fort Thompson Formation lies unconformably upon the Caloosahatchee Marl and is overlain unconformably by the Pamlico Sand or Recent soil and marl. Parker and Cooke (1944, p. 89-96) correlated the beds at old Fort Thompson with the inferred fluctuations of sea level during the Pleistocene Epoch. They considered the Pamlico Sand to be of mid-Wisconsin age, but later, Cooke (1952, p. 51) referred it to the Sangamon Interglaciation. The beds along the river downstream from the Ortona Lock, in the vicinity of station 343 of Parker and Cooke (1944, p. 93), have been studied in detail by the authors. At that locality the Fort Thompson Formation is 6 to 7 feet thick and is described as follows: Thickness Description (feet) Fort Thompson Formation: 10. Shell beds, marine (Coffee Mill Hammock Marl Member) -- 1 -2 Diastem 9. Marl, sandy, containing marine shells in lower part-------- 0 -2 Diastem 8. Marl, fresh-water -----..--.-.-----------------------...................... ... . 7. Shell marl, marine, silty .... ..----.--. -- --.......-.................. -1 Diastem 6. Limestone, fresh-water ...--- .... ------...... ....... --........-----....---. .. 0 - 5. Shell marl, marine, silty ---- --....------................................. 1 -2 Diastem 4. Limestone, fresh-water .... ...-------------...---........... .... 0 % 3. Shell marl, marine, Vermnicularia bed .---------... --.--------........... 1 -2 Diastem 2. Limestone, sandy, fresh-water ....-----------.. ..............-....-. -1% Diastem Caloosahatchee Marl: 1. Shell marl, marine Parker and Cooke included beds 2 and 3 of the section in the Caloosahatchee Marl. However, fresh-water gastropods were abundant in bed 2 for 1,700 and 800 feet, respectively, on the left and right banks of the river. Therefore, the top of the Caloosa- hatchee Marl is placed tentatively below bed 2. Typical Caloosahatchee shells were not found in bed 3. In this area, as noted, the four fresh-water beds (beds 2, 4, 6, and 8) may indicate glaciations, and the six diastems suggest short periods of lowered sea levels and breaks in sedimentation. The deposition of the Anastasia and Fort Thompson Formations and the terrace deposits was the result of the oscillation of sea REPORT OF INVESTIGATIONS NO. 37 level during the Pleistocene. During the interglacial stages the high-level seas covered the area, and during the glacial stages, when the sea levels were below present levels, most of the area was being eroded but fresh-water marls were being deposited in shallow depressions. The Lake Okeechobee-Everglades Basin and a subsidiary basin in the Caloosahatchee River valley probably were lakes or swamps during a part of each glacial period. It appears that a drainageway from the Lake Okeechobee area toward the Gulf of Mexico existed during the glacial periods and conditions were somewhat similar to those prior to the dredging of the Caloosahatchee River. The Fort Thompson Formation generally does not yield large quantities of water in Glades and Hendry counties because the limestones are usually of low permeability and the shell beds contain silt and clay. Small supplies can be obtained from shell beds by jetting and removing the fine materials from the zone surrounding the bottom of well casings. TERRACE DEPOSITS The terrace deposits in Glades and Hendry counties are composed of quartz sand referred by Parker and Cooke (1944, p. 74-77) to the Pamlico, Talbot, and Penholoway terraces. The old shorelines of these deposits occur at about 25 feet, 42 feet, and 70 feet above sea level, respectively, and are associated with glacial control of sea level during the Pleistocene Epoch. Terrace sands mantle all of Glades and Hendry counties, except the areas covered by Recent organic soils and marls in the Ever- glades, and the Lake Flirt basin along the Caloosahatchee River. Usually the sands are 2 to 3 feet thick, but where they overlie old depressions they may be as much as 15 feet thick. The terrace sands lie unconformably upon the Fort Thompson or Anastasia Formations of Pleistocene age, the Caloosahatchee Marl of Pliocene age, and the Tamiami Formation of late Miocene age, and are overlain unconformably by the Lake Flirt Marl and deposits of Recent age. Wells developed in the terrace sands are generally driven sandpoints. Well 237 in northwestern Glades County is a dug well and holds its form because it penetrates iron-cemented "hardpan." The water from this well is undesirable for domestic use because it is high in color and has a high iron content. FLORIDA GEOLOGICAL SURVEY RECENT SERIES The deposits of Recent age in Glades and Hendry counties include the organic soils of the Everglades and the Lake Flirt Marl. The marl and the parent material for most of the organic soils accumulated in a fresh-water environment. LAKE FLIRT MARL The Lake Flirt Marl was the name applied by Sellards (1919, p. 73-74) to the fresh-water deposits overlying the Fort Thompson Formation and the Pamlico Sand in the now-drained Lake Flirt area east of LaBelle. The approximate extent of these fresh-water deposits is shown in figure 2. The maximum thickness of the formation along the banks of the Caloosahatchee River is 6 to 8 feet. In addition to gray and brown marl containing fresh-water gastropods, the formation is composed of dark sticky muck, sandy marl, and carbonaceous sand. The low permeability of the Lake Flirt Marl precludes its develop- ment as an aquifer. ORGANIC SOILS After the close of the Pleistocene Epoch, organic soils began to accumulate in the Lake Okeechobee-Everglades Basin and in shallow ponds, lakes and swamps. The maximum thickness of the organic soils is about 8 feet in eastern Hendry County. They are composed of brown to black peat and muck. Along the western edge of the Everglades, quartz sand from the terrace deposits was reworked and mixed with the organic material. Several samples of peat, collected from the lowermost 6 inches of organic soil that immediately overlie the rock floor of the Everglades, have been dated by radioactive carbon determinations. The age of the peat was determined as follows: mucky peat at the Everglades Experiment Station near Belle Glade in Palm Beach County, 4900 years 200 years; fibrous peat near the same loca- tion, 3,800 years 200 years; and peat from the vicinity of U. S. Highway 27, 10 miles south of Lake Okeechobee in Palm Beach County, 5,050 years 200 years. Peat is considered to be resistant to the lateral seepage of water. This characteristic and the low permeability of the materials underlying the organic soils make flood control and water control feasible in the Everglades area of Glades and Hendry counties REPORT OF INVESTIGATIONS No. 37 through the use of canals, pumps, and levees. The high organic content of the soils makes the ground water contained in the soils undesirable for domestic use. GROUND WATER OCCURRENCE AND MOVEMENT The basic principles that govern the occurrence and movement of ground water have been thoroughly described by Meinzer (1923). Following is a summary of these principles as they relate to Glades and Hendry counties and most areas of southern Florida. The chief source of ground-water recharge in Glades and Hendry counties is rainfall. Part of the rainfall evaporates, a part is absorbed by plants and transpired into the atmosphere, and a part is lost by surface runoff. The remainder infiltrates downward through the surface materials until it reaches the zone of satura- tion to become part of the body of ground water. The upper surface of the saturated zone where not confined by an impermeable bed is the water table. Ground water is stored in the openings, solution cavities, and pore spaces within the consolidated and unconsolidated materials of the earth's crust. The amount of water that can be stored in water-bearing materials is determined by the porosity of the materials. Porosity is controlled by such factors as the shape, arrangement and assortment of the components, the amount of cementing material in the interstices, and the degree of compaction of the sediments. The permeability of a water-bearing stratum is its ability to transmit water under a hydraulic gradient. Clay, marl, and fine sand, although highly porous, are of low permeability, but coarse sand, gravel, and cavernous limestone are highly permeable because the interstices are large and interconnected. A formation, group of formations, or part of a formation that transmits appreciable quantities of water to wells and springs is called an aquifer. The water table is an undulating surface that conforms in a general way to the topography of the land. It fluctuates seasonally in southern Florida, rising during rainy seasons and declining during dry periods, and responds to such forces as evaporation, transpiration, and pumping from wells. Ground water moves down- gradient from areas of recharge to areas of discharge. The gradient of the water table depends upon the thickness and FLORIDA GEOLOGICAL SURVEY permeability of the aquifer and the quantity of water moving through the aquifer. A steeper gradient is required to move a given amount of water through an aquifer of low permeability than through an aquifer of high permeability. An aquifer where the upper surface of the zone of saturation is not confined by impermeable material contains water under nonartesian (or water-table) conditions. The water level in a well penetrating the saturated zone of an unconfined aquifer is a measure of the altitude of the water table. Where ground water has moved laterally into permeable material that is overlain by an impermeable layer and it is under sufficient pressure to rise above the top of the material containing it, it is said to occur under artesian (confined) conditions. The water level in a well penetrating an artesian aquifer will rise above the top of the aquifer to a point that is the approximate measurement of the pressure head. The pressure head is due to the weight of the water in upgradient areas of the aquifer. Glades and Hendry counties are underlain by an artesian system that extends beneath Florida and southeastern Georgia. The system will yield flowing water to deep wells in all Hendry County and all but northwestern Glades County. Glades and Hendry counties are underlain at shallow depth by less extensive aquifers which exhibit both nonartesian and artesian character- istics. Water levels in wells penetrating these aquifers respond to local recharge by rainfall and to evapotranspiration, but also are affected by changes in barometric pressure and by earthquakes. Figures 9-12 show the locations of deep and shallow wells inventoried in Glades and Hendry counties. FLORIDAN AQUIFER The principal artesian aquifer beneath Florida was described by Stringfield (1936) and was named the Floridan aquifer by Parker (1951, p. 819). The part of the Floridan aquifer penetrated by deep artesian wells in Glades and Hendry counties consists of water-bearing limestones that range in age from middle Miocene to Eocene. The depth of the base of the Floridan aquifer is not known, but rocks older than Eocene probably contain highly mineralized water in most of Glades and Hendry counties. The aquifer is overlain by clay, sandy clay, and marl of the Hawthorn Formation, which form a relatively impermeable confining layer. The clay and marl in the lower part of the Hawthorn Formation are interbedded with water-bearing limestones. These limestones. [2 .. .-'- L j.- -pJLa -'. E '0 -. - -- 5 55.T e S OLADES COUNTY \ o 0 '"* 4 -r OKE *tag. I s o A .' NONFLOWI1G WELL Of c s. 3r E A ...... ..... US ........... O A M H I G H L A N D S C O U N T Y R 3 0E 5 6 1 4I GLADES COUNTY F igure 9. Glades County showing the locations of wells. o?821 O I*'u N.tf l4 'AK ' FiC ue. 9.b Glades County showing the l ti of wells. S -**---' *. & COUNTY \,,,,,/pjj. "nc Fiue9WldsCut hwn h oain fwls FLORIDA GEOLOGICAL SURVEY Figure 10. Hendry County showing the locations of wells. which usually occur at depths ranging from 300 to 400 feet, are not as productive as the deeper limestones; therefore, most of the artesian wells in Glades and Hendry counties are bottomed in the highly permeable Tampa Formation or the Suwannee Limestone. The limestones of the Floridan aquifer in Glades and Hendry counties are not homogenous, and in many cases, most of the yield of a given well may be contributed by two or three thin, highly permeable zones. One of the highly productive parts of the aquifer is at the top of the Tampa Formation. The limestones in the lower part of the Hawthorn Formation are included as part of the aquifer unit; however, the artesian pressure in these layers is much lower than it is in the Tampa Formation, which suggests that they ma3 constitute a separate aquifer. In table 4 (Bishop, 1956, p. 113) the artesian pressure ant the yield of well 22, Glades County, increased sharply between depths of 573 feet and 610 feet, below the land surface as the well passed from the Hawthorn Formation into the Tampi REPORT OF INVESTIGATIONS No. 37 I 11 174_____ J Figure 11. LaBelle and vicinity showing the locations of wells. Formation. After the first major flow (200 gpm) was obtained at 610 feet, the yield from the remainder of the hole (610 to 1,215 feet) increased at an irregular rate to 585 gpm. The data indicate that the interval between 610 and 616 feet in the upper part of the Tampa Formation is the zone of the highest permeability at this site. FLORIDA GEOLOGICAL SURVEY EXPLANATION LINE *229 Nonfl oing well 1 '196 ind number I SCA:_E IN MILES '230 Figure 12. Clewiston and vicinity showing the locations of wells. Several flowing wells are used to irrigate pastures and farmland north of the Caloosahatchee River, about 6 miles northeast of LaBelle. Fairly good geologic and hydrologic data and accurate well construction information are available on wells 201, 238, and 239 in this area of Glades County. Wells 201 and 238 were cased to a depth of 203 feet, but the original drilled depths of the wells differed by 142 feet (well 201, 642 feet; well 238, 500 feet). When the wells were completed, well 201 yielded 385 gpm and well 238 yielded 730 gpm. Well 239, 1 mile to the northeast, was cased to a depth of 254 feet, and was completed at a depth of 716 feet; its initial yield was 310 gpm. The TABLE 4.1 Water-level and Flow Measurements Made During Drilling of Well 22, Glades County I Casing seated at 432 feet] Depth of well below Water level Average increase land surface above land Yield by in yield per foot Geologic Date ( feet) surface (feet) flow (gpm) of interval (gpm) formation 1951 Feb. 24 500 __ Trace Hawthorn Feb. 27 515 6.0 Do. Feb. 23 573 6.0 Do. Mar. 1 610 30.0 200 Tampa Mar. 1 616 290 15.0 Do. Mar. 1 632 32.0 Ocala Mar. 1 667 310 0.4 Do. Mar. 1 677 340 3.0 Do. Mar. 1 670 31.0 Do. Mar. 2 854 395 0.3 Do. Mar. 5 1.119 420 .1 Avon Park Mar. 5 1,134 445 1.7 Do. Mar. 5 1,164 480 1.2 Lake City Mar. 6 1,190 30.0 565 3.3 Do. Mar. 6 1.215 31.0 585 .8 Do. iTable condensed from Bishop, 1956 (p. 113). REPORT OF INVESTIGATIONS NO. 37 relatively large differences in the amount of casing in the wells, the amount of aquifer penetration needed to obtain substantial yields, and the differences in the individual well yields indicate that the confining beds of the Hawthorn Formation in this general area are of nonuniform thickness and lithology, and that the water-yielding properties of the limestones composing the aquifer differ both laterally and vertically. Two months after these wells were drilled additional measure- ments of -depth and flow were made, and traverses with a deep well current meter were made in wells 201 and 238 to measure the velocity of flow through the well bores at different depths. The measurements showed that the depth and yield of well 238 were the same as originally determined, but that the open-hole part of well 201 had filled in 38 feet and the yield had been reduced by 35 gpm. Data obtained from the current-meter traverses in these wells are shown in figure 13. The graphs show the relative velocity of the ground water moving upward at different depths in the wells and presents the percentage of the total flow that enters the well bores from different intervals. About 40 percent of the total yield of well 201 was contributed by the limestone section between 510-520 feet; nearly 40 percent of the total flow of well 238 was contributed by the 5-foot section at the bottom of the well. Flow measurements made in these wells in May 1958 showed that the yield of well 238 had declined from 730 to 650 gpm, and that of well 239 had declined from 310 to 230 gpm. Similar studies were made on two 8-inch flowing wells in Hendry County (wells 278 and 279), about 9 miles southwest of LaBelle. The yield of well 279 diminished from 500 gpm in August 1953 to 200 gpm in March 1954. The graph of the results of the current-meter traverse of well 279 (fig. 13) shows that 40 percent of the yield was contributed from the interval between 440 and 460 feet. Flow data obtained in May 1958 indicate that the yield of well 279 had not changed from the 200 gpm rate of March 1954. Well 278, a quarter of a mile south of well 279, yielded 760 gpm when it was completed in July 1953, but by March 1954 the discharge had diminished to 400 gpm, and by May 1958 it was 320 gpm. The well has 8-inch casing from the land surface to a depth of 290 feet and 6-inch casing between 378 and 520 feet, leaving an open hole between 290 and 378 feet and between 520 feet and the bottom of the well, at 790 feet. Some yield was obtained from the zone between 290 and 378 feet, but the source of most of the water apparently was the zone below the bottom FLORIDA GEOLOGICAL SURVEY I DEPTHIN FEET BELOW LAND SURFACE I Figure 13. Graphs showing the distribution of flow in selected wells in Glades and Hendry counties. of the lower casing. Water samples collected at 340 and 377 feet (upper open-hole part) contained 1,000 ppm of chloride, practically the same concentration as in samples obtained from the lower open-hole section and also from the discharge outlet. However, a water sample taken at a depth of 400 feet in well 279, to the north, contained 665 ppm of chloride. This suggests that the 400-foot zone, which had been cased off in well 278, contains relatively fresh water, and that the major part of the yield is from the deeper saline zones. If the open-hole part of a flowing well is of uniform diameter and the aquifer has uniform pressure, the water velocity should increase from the bottom of the hole upward. The flow distribution in well 279 (fig. 13) indicates that the size of the hole is not uniform. Where the hole is enlarged opposite sections of the aquifer consisting of soft material, the velocity of the water decreases because of the larger cross-sectional area. Possibly some decrease in flow may result from loss of water into sections of the GLADES COUNTY WELL 201 DEPTH 604 Fl CASED 203 Fl FLOW 350 GPM REPORT OF INVESTIGATIONS NO. 37 borehole where the pressure is lower than the pressure in the main yielding zones. PIEZOMETRIC SURFACE The piezometric surface is an imaginary surface representing the pressure head of water confined in an artesian aquifer. It is defined by the height to which water will rise in tightly cased wells that penetrate the aquifer. Where the piezometric surface is higher than the land surface, wells tapping the artesian aquifer will flow. In peninsular Florida the piezometric surface is highest in central Polk County where the aquifer is recharged, and lowest in coastal areas where discharge takes place. Over much of south central Florida the piezometric surface is relatively flat and has a general southeasterly slope. The configuration of the piezometric surface in Glades and Hendry counties is shown in figure 14, by contours which indicate that artesian water in the Floridan aquifer is flowing generally southeastward from the Highlands Ridge area into Glades County. A mound in the piezometric surface in eastern Hendry County and southwestern Palm Beach County (fig. 14) indicates that ground water is flowing outward in all directions from that generally high area. This suggests that the Floridan aquifer is being recharged in that area; however, the height of the piezometric surface there is 30 feet or more above the land surface, and thus there is no possibility of local downward recharge. This piezometric high probably is a residual mound that has resulted from the discharge of flowing wells in the areas to the northwest. RECHARGE At some places in north, central, and northwestern Florida the Floridan aquifer is exposed at the surface, but throughout the remainder of Florida the aquifer dips beneath the surface and is covered by layers of sand and clay of low permeability which form a confining unit. At the outcrop area the aquifer is recharged directly by rainfall. Recharge to the Floridan aquifer occurs also in the high areas of central Florida where the water table is perennially higher than the piezometric surface of the aquifer; replenishment occurs by downward infiltration through semi- permeable layers of the Hawthorn Formation. According to Stringfield (1936, p. 148) the artesian aquifer in parts of central FLORIDA GEOLOGICAL SURVEY i OKEECHOBEE 4- OORE HAVEN / .56 M 6 E END COUNTY A ELLE .- L .52 CLEWISTON 0 / \ 53 7 I .9 / IC 56 54 5 61 s COuLIER feet above0 55mean sea level in 1958; Well and water leveling feet Line showing approximate (fig. altitude ofthe piezometric surf ace, in feet above mean sea level in 1958; dashed where inferred ._X _. HE\aY_ COUN_ _____CJ" *59 \ '--' -''OLL5 R COUNTY Well and water level,in feet A-----A' Line of water-level profile(fig.15) SCALE IN MILES 2 0 2 4 6 8 10 54 Figure 14. Glades and Hendry counties showing the configuration of the piezometric surface of the Floridan aquifer, 1958. REPORT OF INVESTIGATIONS NO. 37 Florida is blanketed by permeable material, thus permitting ready recharge to the aquifer. It is probable that replenishment to the Floridan aquifer by downward infiltration occurs in much of the Highlands Ridge area of central Florida. Water-level measurements by Bishop (1956, p. 46-48), during the drilling of a deep well in southern Highlands County, substantiate the theory that recharge to the Floridan aquifer occurs as far south as the town of Venus in southern Highlands County. The water in the Floridan aquifer beneath Glades and Hendry counties moves southward beneath the con- fining layers of the Hawthorn Formation in a general direction normal to the piezometric contours shown in figure 14. DISCHARGE Most of the discharge from the Floridan aquifer in Glades and Hendry counties probably occurs through artesian wells used to irrigate winter vegetable crops and pastureland. The total water discharged during the seasons of heavy irrigation is about 10 mgd (million gallons per day). Hendry (1957, p. 19) estimated that about 50 wild, flowing wells in the two counties discharge water at a total rate of approximately 3 mgd. Many of these wells are west and southwest of LaBelle. The layers and lenses of clay, sandy clay, and fine sand of low permeability that compose the middle and upper parts of the Hawthorn Formation in the two counties tend to prevent upward leakage from the Floridan aquifer. However, where sand is the chief component of the confining unit or where the Hawthorn Formation is thin (figs. 6, 7), upward leakage may occur because of the high pressure differential (30-40 feet) between the piezometric surface and the water table. WATER-LEVEL FLUCTUATIONS The water levels in an artesian aquifer fluctuate in response to recharge by rainfall, discharge, earthquakes, and variations of barometric pressure. Fluctuations due to rainfall are most apparent in the vicinity of the recharge area. However, water levels in deep wells in Glades and Hendry counties are only slightly affected by seasonal rainfall because the wells are a great distance 'rom the recharge area. Large fluctuations of the piezometric surface are due to discharge from wells during periods of irrigation. FLORIDA GEOLOGICAL SURVEY Figures 9, 10, and 11 show the locations of inventoried flowing wells in Glades and Hendry counties, though they do not show all the flowing wells in the area. The concentration of wells is greatest along the Caloosahatchee River from Ortona westward to the Lee County boundary. The cones of depression in the piezometric surface (fig. 14) are evidence of the heavy discharge from the Floridan aquifer in this area where many wells have been in use for 50 years or more. It is estimated that 50 percent of them are no longer maintained and are leaking through corroded casings or are flowing wild. Such heavy discharge over a long period of time is responsible for the overall decline in pressure in that area, and this may have caused the quality of the water to deteriorate. Probably the quality of the water derived from the Floridan aquifer in the vicinity of LaBelle during the early days of the development was superior to the quality in 1958. A second area of heavy water use is in northeastern Glades County and the adjoining part of Okeechobee County, where crops and pastures are frequently irrigated. The lowering of the piezometric surface caused by this discharge is shown in figure 14. The lowered pressure in this area and the lowered pressure caused by discharging wells north of Lakeport and in the vicinity of Palmdale have produced the northeastward-trending trough in the piezometric surface in Glades County. Few, if any, artesian wells have been drilled to the Floridan aquifer in the Everglades south of Lake Okeechobee, and the piezometric surface in this area has remained at its approximate original level. Artesian water is moving downgradient from this area of high pressure and as the mound is not being recharged, a slow decline of pressure can be expected until a new gradient from the recharge area is established. It may be many years before this gradient adjustment is completed. Figure 15 is a series of water-level profiles of the Floridan aquifer in Glades and Hendry counties. These profiles show the effect that the discharging wells have on the piezometric surface. Profile A-A' shows that recharging water moves downgradient from the high areas in Highlands County toward the cone of depression in the vicinity of LaBelle. Profile B-B' crosses from the high water level in Highlands County southeastward through the saddle-shaped depression in the vicinity of Palmdale to the residual high-pressure area in eastern Hendry County. Profile C-C' shows a relatively steep gradient from Highlands County southeast- ward to the area of heavy withdrawals near lake Okeechobee. REPORT OF INVESTIGATIONS NO. 37 I B B' S HIGHLANDS z GLADES HENRY COUNTY COUNTY COUNTY M<6 I W I . . =50 _j G> C HIGHLANDS GLADES coW 60 COUNTY I COUNTY --J Ar NML t- 0 P See figure 14 for location of profiles Figure 15. Profiles of the piezometric surface of the Floridan aquifer in Glades and Hendry counties, 1958. SHALLOW AQUIFERS The shallow aquifers in Glades and Hendry counties range in age from middle Miocene to Pleistocene. Permeable beds of shell, limestone, or mixtures of sand and gravel in the Tamiami Formation and the upper part of the Hawthorn Formation are the principal sources of ground water for shallow wells. Wells tapping these aquifers range in depth from about 10 feet to more than 300 feet. The shallower wells generally penetrate shell beds or lime- stone in the Tamiami Formation. They are finished with a few feet of open hole and yield relatively small amounts of water in Glades County and most of northern and western Hendry County. In 1953 few irrigation wells produced water from the shallow aquifers in Glades County because the Floridan aquifer, in most areas yielded usable water in large quantities without the use of pumps. In Hendry County the Floridan aquifer yields water that is generally unsuitable for irrigation, and farmers must depend on the shallow aquifers for fresh-water supplies. Truck-crop farmers FLORIDA GEOLOGICAL SURVEY in the Devil's Garden, the Big Cypress Swamp, and the Everglades areas irrigate with wells that range in depth from about 50 feet to more than 300 feet. The deepest of these is well 194, 6 miles northeast of Felda (fig. 10); it was drilled to a depth of 326 feet, and was reported to tap one of the gravel beds within the Hawthorn Formation. The principal shallow aquifer in the area is in the southern and central parts of Hendry County, and is composed of highly permeable limestone of the Tamiami Formation. Geologic information obtained from well 131 in Collier County, due east of Immokalee at the Hendry County boundary, shows the top of the aquifer to be at a depth of 22 feet, and that permeable limestone extends to a depth of at least 54 feet. In this area the aquifer is overlain by 5 feet of surficial, medium-grained sand and 17 feet of sandy, shelly clay of low permeability. The clay retards the down- ward infiltration of water to the aquifer. Further information indicates that the aquifer thins out 3 to 5 miles west of well 131 in Collier County. The increase in the depth of wells eastward from well 131 suggests that the highly permeable limestone in the aquifer dips to the east. The depth to the top of the limestone in the Devil's Garden area (fig. 2) is about 120 feet. Eight miles north of well 131 the aquifer probably is thinner, as indicated by the shallow depth of irrigation wells in that area. The greatest extent of the aquifer is southward, where it probably underlies all of southern Hendry County and most of Collier County. Similar permeable limestone was noted in rockpits as far south as southern Collier County. Data from well 4, 9 miles west of Clewiston, in Hendry County, indicate that the top of a shallow aquifer in that area occurs at 96 feet below the land surface. This aquifer extends to 127 feet and is reported to be composed of fine to coarse gray sand mixed with well rounded pebbles. The aquifer may be the basal part of the Tamiami Formation or possibly one of the pebble beds of the Hawthorn Formation. The well is finished with 5 feet of slotted casing, is gravel packed, and is reported to yield 180 gpm. The overlying material is composed of sandy, shelly marl of low permeability. Wells penetrating the shallow permeable layers in LaBelle and vicinity range in depth from about 60 to 175 feet, but most are between 20 and 100 feet deep. A study of rock cuttings taken during the drilling of well 277, in the southern part of Labelle, shows that layers of clay, shelly marl, and fine sand are interbedded with layers of limestone to a depth of 170 feet. The clay and REPORT OF INVESTIGATIONS NO. 37 shelly marl are of low permeability and tend to retard ground-water movement between the thin sections of higher permeability. The sediments in general are poorly sorted and grade laterally as well as vertically into material of different composition. The shallow sediments in Glades County generally have low to moderate permeability, and most large capacity wells penetrate the Floridan aquifer even though the quality of the water is usually poorer. The shallow aquifers in Glades County are composed of sand and pebble beds or discontinuous limestone beds of the Haw- thorn Formation. The yield from shallow aquifers in Glades County generally is lower than that from shallow aquifers in Hendry County. WATER-LEVEL FLUCTUATIONS Water levels in wells that tap shallow aquifers in Glades and Hendry counties normally are within a few feet of the land surface. However, during rainy seasons the water levels in wells in many areas rise above the land surface. Well 128, 3 miles west of LaBelle and south of the Caloosahatchee River in Hendry County, flows throughout most of the year. The well was reported to penetrate a permeable shell bed at a depth of 76 feet. Records of fluctuations of water levels in shallow observation wells in and adjacent to Hendry County have been obtained since 1950. Automatic gages provide a continuous record of the daily changes and the seasonal trends of the water levels. Hydrographs of wells 3 and 5, in Hendry County south of Clewiston, and well 131, in Collier County east of Immokalee, are shown in figure 16. They reveal ground-water levels are usually at low stage during winter and spring and are high during and immediately after the rainy season in summer and early fall. The maximum range of fluctuation is about 5 feet. The greatest rise in water level accompanies the first heavy rainfall of the wet season. The surface materials become saturated nearly to the land surface and subsequent rainfall causes inter- mittent flooding. The hydrograph for well 3, 30 miles south of Clewiston, shows that the flooding had occurred in that area many times during each rainy season and that the area was flooded nearly the entire year of 1958. Evapotranspiration is another cause of water-level fluctuations in shallow observation wells. The decline of water levels caused by evapotranspiration ranges from 0.05 to 0.15 foot per day. When overland runoff stops after the rainy season, the persistent decline N Wi WELL 3, HENDRY COUNTY 30 miles south of Clewiston wo +SpvyF VT1 111111[m il TF ,WELL 5 HENRY COUNTY I I I II Iij` 1 S 15 miles southwest of Clowiston 1 3-0 W g21 WELL 131, COLLIER COUNTY N\ Il1 :1 m i iiia ii i H l I I 2ImLLIII Ii1 mileseastof I II 'oj 11. II I LI LLY* 14A I 1l It 1 1!i Jill J 11 1 JJI Kr'F41 Figure 16. Hydrographs of wells 3 and 5 in Hendry County and well 131 in Collier County. 0 161A isg& i lll i ri REPORT OF INVESTIGATIONS No. 37 of water levels throughout the area is the result of the relatively high rate of evapotranspiration. A water-level recording gage was installed on well 234 in LaBelle to determine the relation between the stage of the Caloosahatchee River and the water table adjacent to the river during 1953-54. This relation is shown in the hydrographs of figure 17. The daily rainfall at LaBelle is included also. The hydrograph shows the daily-average stage of the Caloosahatchee River at LaBelle and is probably indicative of the fluctuations as far upstream as the Ortona Lock, one of the regulatory structures which control the water level of Lake Okeechobee. Fluctuations of river stage at LaBelle are caused by boat-lock operation, by variations of discharge from Lake Okeechobee through the locks at Ortona, and by gulf tides. The large fluctuations in figure 17 are caused by changes in the rate of discharge through the structure at Ortona. During the period from early February to late May 1953 the locks were open and the average river stage at LaBelle was between 3.0 and 3.5 feet above msl. On May 22, 1953, the locks were closed and the river stage at LaBelle declined to 0.5 foot above msl. Figure 17 shows that the 2.5-foot drop in stage had no influence on the water level in well 234, less than 1,000 feet from the river. Similarly the large changes in river stage that occurred during September and October 1954 produced no corresponding changes in water level in well 234. Lithologic information obtained from well 234 and from out- crops along the riverbanks at LaBelle shows that sandy and shelly material of moderate permeability extends from the land surface to about 6 feet above sea level. These are underlain by about 6 feet of sandy marl of low permeability. A relatively impermeable layer of silty clay of the Tamiami Formation forms the base of the riverbank at an elevation of about 1 foot above sea level. Apparently, the sediments of predominantly low permeability tend to minimize the effect on ground-water levels produced by rapid stage changes in the Caloosahatchee River, so that the effect extends less than 1,000 feet from the river. RECHARGE AND DISCHARGE The water that replenishes the shallow aquifers in Glades and Hendry counties is derived from local rainfall. The terrain is essentially flat and covered by moderately permeable sand, which permits rapid infiltration to the water table. As the water table o 9 I 1c. a upl9 a o p 195 a I P AI ---- --tii--- -- An - AT LA BELLE & A~ ABU \1 --- --- --- --- ---- --- --- -------- -- -- SAILY AVERAGE N o \. W SI II I OJ-^i-Ll l..LL[ td.ll J L I.,I __ I. ..I I, s I h. l ,..,, l. ,1 Ro slar Figure 17. Hydrographs of well 234 and the Caloosahatchee River at LaBelle compared with rainfall for the period 1953-54. 0 REPORT OF INVESTIGATIONS NO. 37 throughout the area is never more than a few feet below the land surface, the shallow sands quickly become saturated early in the rainy season. As a result, ponding is widespread and slow overland flow occurs. Thin layers of fine sand, marl, or clay of low permeability that overlie shallow, aquifers tend to impede down- ward infiltration. Discharge of ground water occurs by outflow to the Caloosa- hatchee River, Fisheating Creek, numerous drainage canals, and Lake Okeechobee; by evapotranspiration; and by pumping from wells. Ground-water losses by outflow along the uncontrolled reach of the Caloosahatchee River probably are small because of the general low permeability of the shallow sediments (see discussion of water-level fluctuations). Evapotranspiration is responsible for the largest losses of ground water from storage, because the water table is near the surface throughout the year. The quantity of water discharged by wells is negligible compared to natural discharge. HYDRAULIC CHARACTERISTICS The ability of an aquifer to transmit water is expressed by the coefficient of transmissibility. The coefficient. of transmissibility is defined as the quantity of water, in gallons per day, that will move through a vertical section of the aquifer 1 foot wide and extending the full height of the aquifer, under a unit hydraulic gradient at the prevailing temperature of the water (Theis, 1938, p. 894). The coefficient of storage is a measure of the capacity of the aquifer to store water, and is defined as the volume of water released from or taken into storage per unit surface of the aquifer per unit change in the component of head normal to that surface. The leakage coefficient (Hantush, 1956, p. 702) characterizes the ability of semiconfining layers above or below an aquifer to transmit water. It is the quantity of water that crosses a unit area of the interface between the permeable section and its confining layer with a unit hydraulic gradient between the head in the permeable section and the section supplying the leakage. The coefficients of transmissibility, storage, and leakage that pertain to shallow aquifers in Glades and Hendry counties were determined by aquifer tests at seven sites (fig. 18). During each test, the changes in water level were measured in observation wells located at different distances from the pumped well. Figure 19 is a semilogarithmic graph of water-level drawdowns in observation wells versus the distance from the pumping wells at five of the FLORIDA GEOLOGICAL SURVEY I- r------- HIGHLAN S COUNTY > GLADES COUNTY i ) | LAKE OKEECHOBEE T = 10000 S = .00025 OOREHAVEN ----- .; GLADES COUNTY a...sLA BELLE HENRY COUNTY L CLEWISTON. A T= 7Q.0OO SS=.00061 I i T= 115.000 1 T-u.2rw Sz.00025 -d COLLIER COUNTY I EXPLANATION IE B=TEST AREA T=COEFFICIENT OF TRANSMISSIBILITY,GPD PER FTj S=COEFFICIENT OF STORAGE I 1 0 2 4 6 to0 S=.0012 W T= 96000 S=.00031 0 T= 505.000 F S=,00016 OG T= 250000 S=: .00045 i i i i HENRY COUNTY -.-.-. .- .- J Figure 18. Coefficients of transmissibility and storage determined at test sites in Glades, Hendry, and Collier counties in shallow aquifers. REPORT OF INVESTIGATIONS NO. 37 51 DISTANCE, IN FEET FROM PUMPING WELL 2.5 8 08 8 8 s o 8 8 oi I- t r /2 LL .5/ A - Figure 19. Composite of semilogarithhic distance-drawdown graphs of five indicates the approximate drawdown that would be expected at a given distance from a well pumped at the indicated rate. There- fore the graph can be used to determine the optimum pumping rates and proper spacing for wells. The field data obtained during the aquifer tests .are shown in figure 20. The time-drawdown graphs for each test area are accompanied by a sketch showing the location of the wells used in the tests. The natural fluctuations of the water-level were recorded for periods of 24 hours both before and after each test to determine the fluctuations caused by factors other than pumping, such as changes in atmospheric pressure and evapotranspiration. These TEST G 6400 pm 8 4 .....................I Figure 20. Time-drawdown graphs of water levels in observation wells, and sketches showing locations of wells used in aquifer tests. TEST A 310 gpm I.-- I.--- REPORT OF INVESTIGATIONS NO. 37 corrections were subtracted, and the corrected drawdowns shown are the result of pumping only. The amount of correction in some cases is very significant, as indicated by the graphs of well 285 in test E (fig. 20). The corrected water-level drawdowns, in feet, were plotted (on logarithmic paper) against time, in minutes, since pumping started and divided by the square of the distance, in feet, between the pumping well and the observation well (t/r2). The resulting curve for each observation well was matched to a family of leaky-aquifer type curves developed by H. H. Cooper, Jr., of the U. S. Geological Survey, from the equations developed by Hantush and Jacob (1955). By superposition, match points were established for the best fit of the corrected data to the type curves, and the coefficients of transmissibility, storage, and leakage were calculated from the match points. Table 5 gives the results of these computa- tions for the seven aquifer tests. The coefficients of transmissibility and storage shown on the map of figure 18 represent the average values for each test. The calculated values indicate that the aquifer composed of limestone of the Tamiami Formation that underlies the area east of Immokalee (test E) has the highest transmissibility. The results of tests F and G show a decrease in the coefficient of transmissibility to the east. This confirms information reported by well drillers that limestone layers become thinner in the vicinity of test G and much of the material is composed of fine and medium sand. A marked decrease in the coefficient of trans- missibility is shown also to the north in test sites B and C. In these areas the aquifer is probably thin or the limestone section grades to a marly, partly consolidated shell bed. A basic assumption of the leaky-aquifer method of analysis is that the water level in the material supplying the leakage does not decline during the period of pumping. Under this condition, when the cone of depression (which forms around the pumped well) has expanded to the extent that the total rate of downward leakage is equal to the rate of withdrawal no further appreciable drawdown will take place in the aquifer as a result of pumping. This condition is closely approximated when an area is flooded or where an area is dissected by a network of canals in which water can be maintained at a constant level. On the other hand, where there is no source of water to maintain downward leakage at a constant rate, the water table will begin to decline after prolonged pumping. As the water table declines, the rate of downward leakage is reduced because of the reduction TABLE 5, Coefficients of Transmissibility, Storage, and Leakage in Glades, Hendry and Eastern Collier Counties Well no.' Depth of well (feet) 0 O0 'i - .... .. ........ A 5.20.58 HE 813 HE 312 125 125 1,850 310 70,000 6.05x10-- 2.77x10--J0 8/ .81 B 7-80-58 HE 820 HE 822 84 84 165 700 100,000 1.38x10-3 4.80x10-0 28 8.67 B 7-80-58 HE 820 HE 828 84 28 2,400 700 140,000 0.20x10-4 1.44x10-o 28 .66 C 6-20-58 HE 800 HE 299 97 72 015 840 110,000 2.78x10-4 1.08x10-6 24 8.05 C 6-20-58 HE 800 HE 801 97 98 2,800 840 120,000 2.30x10-- 1.03x10-- 24 1.12 D 8-14-58 GL 260 GL 258 80 78 3,200 340 115,000 2.95x10-1- 1.65x10-7 1111 .51 D 8-14-58 GL 260 GL 250 80 82 855 340 105,000 2.06x10-,4 1.81x10-7 11 1, 1.57 E 6-17-58 HE 286 HE 285 40 40 1,380 1,800 085,000 2.98x10-- 2.33x10-7 25 .63 E 6-17-58 HE 286 HE 287 40 51 3,220 1,300 1,070,000 1.98x10-4 5.47x10-7 25 .40 E 0-17-58 HE 280 HE 288 40 40 3,580 1,800 905,000 2.73x10-4 1.08x10-o 26 .82 E 6-17-58 HE 286 HE 806 40 41 140 1,800 085,000 4.16x10-4 2.05x10-- 25 1.28 E 6-17-58 HE 286 C 181 40 54 2,750 1,800 995,000 2.76x10-4 1.10x10-0 25 .41 E 6-17-58 E 286 C 1065 40 51 5,550 1,800 880,000 8.85x10-4 1.60x10- 25 .21 F 6-18-58 HE 289 HE 290 70 80 1,800 1,570 500,000 1.63x10-4 2.80x10-7 14 1.41 F 6-18-58 HE 289 HE 291 70 92 2,800 1,570 515,000 1.49x10-4 8.60x10-7 14 1.21 G 6- 3-58 HE 808 HE 802 120 121 600 1,400 280,000 6.00x10-4 5.00x10-7 48 8.80 G 6-. 8-58 HE 808 HE 304 120 122 1,415 1,400 265,000 2.97x10-4 1.23x10-7 43 2.68 'C-Collier County, GL-Glades County, HE-Hendry County. "Gpd per square foot per foot of vertical head; Hantush, 1956, p. 706. REPORT OF INVESTIGATIONS NO. 37 of head differential between the water table and the piezometric (pressure) surface of the highly permeable section of the aquifer. The cone of depression then must expand to intercept additional water to supply the pumping well. After a long period of pumping and no replenishment to the shallow aquifer, the water table will lower gradually and tend to coincide with the piezometric surface. The entire system will then behave as an unconfined unit. These drawdown conditions are pictured in figure 21, which shows semilogarithmic time-drawdown graphs of four of the observation wells used in test E. In addition to the corrected draw- down information obtained during the test, the graphs show the drawdowns that would have occurred, theoretically, if the aquifer were (1) artesian, curve A, (2) unconfined, curve B, (3) leaky with an unlimited source of downward leakage, curve C, (4) leaky with a limited source of downward leakage, curve D. Curve A was plotted by using the coefficients of transmissibility and storage of the highly permeable section of the aquifer, as determined by the leaky-aquifer method. For this case it was assumed that the aquifer is infinite, is bounded above and below by impermeable materials, and receives no recharge during the pumping period. Curve B was constructed by using a coefficient of transmissibility 10 per cent higher than the average coefficient of the test area, as determined by the leaky-aquifer method, and assigning a storage coefficient of 0.15 (a typical value for unconfined aquifers). Curve C is a plot of the corrected drawdowns obtained during the test (solid circles) with the plots extended (open circles) to conform with ideal leaky-aquifer conditions, which assume that an unlimited source of supply is available at the surface, and that no further drawdown occurs after equilibrium is reached. Curve D is transitional between ideal leaky-aquifer conditions and leaky- aquifer conditions that prevail in the field, where actual unwatering of the aquifer occurs. This curve predicts the water-level draw- downs caused by constant prolonged pumping and no recharge by rainfall. The graphs in figure 22 show similar drawdown information for test areas B in Hendry County and D in Glades County (fig. 18). In Glades and Hendry counties ground-water levels fluctuate seasonally, but the average yearly water levels are reasonably constant (fig. 16). Even in agricultural areas where irrigation is heavy, the wide cones of depression developed by pumping do not cause large changes in water levels from year to year. This is due to the fact that under existing rates of pumping complete Figure 21. Semilogarithmic time-drawdown graphs of four observation wells in test area E. 0-0 000--,, -00. 0000 -'000000 URVE D- WELL 259 CURVE A GLADES COUNTY 0 --"% --o- v - ICURVE B 00 0 _110 00 0 00000 00 O OO 00 CURERVE C 1.0 EXPLANATION O--VI Theoretical drawown, arteson conditions 0 CURVE D S(no recharge) CU RVE B Theoretical draw wn, unconfined conditions CURVE A 2.0 (no recharge) CURVE C WELL 258 Drowdown,leoky-aqu for conditions GLA C NTY 0 GLADES COUNTY 2.5 Observed draWdown Theoretical drawdown,constant leakage 3.0 CURVE O Theoretical drawdown,leaky-aqulfer conditions 5.. (limited leakage) 0 I- 1--f 0 z O2 "-1 Figure 22. Semilogarithmic time-drawdown graphs of observation wells in test areas B and D. FLORIDA GEOLOGICAL SURVEY replenishment of the aquifers occurs during each rainy season. Large local drawdowns do not occur, because a large amount of surface water and shallow ground water is salvaged as a result of reduction in runoff and evapotranspiration in the areas affected by pumping. During dry seasons, 2 or 3 months may elapse without an appreciable rainfall in Glades and Hendry counties. These rainless periods may be further prolonged during severe droughts. It is important, therefore, to estimate the combined effect that long rainless periods and prolonged, constant pumping would have on the water level in a given area. A 6-month period was selected as the maximum duration of such a rainless interval. Figure 23 shows the maximum drawdowns that would occur at the end of 6 months, at different distances from a well pumped at selected rates in each of six test areas. It was assumed that nonartesian conditions prevailed in each area after 6 months of pumping; therefore, the graphs were drawn in accordance with the coefficients of transmissibility shown in table 5, but increased by 10 percent to include the transmissibility of the semiconfining beds, and as assumed coefficient of storage of 0.15. If the coefficient of storage in a given area is less than 0.15, the predicted drawdowns will be greater than those indicated in figure 23. When several wells in a large tract are pumped continuously, the composite drawdown at a particular point can be predicted by summing the effects that each pumping well would have at that time. Because drawdown is approximately proportional to the rate of pumping, the effect of any selected pumping rate can be interpolated from figure 23. QUALITY OF WATER All ground water contains dissolved minerals as a result of the solvent action of the water as it moves through the rocks. The character and the quantity of the constituents in the water are determined by the following: (1) the rate of ground-water flow; (2) the composition of the materials through which the water moves; (3) the temperature and pressure of the water; and (4) the presence of other materials in solution or suspension. Table 6 is a compilation of complete chemical analyses of water samples from 23 wells in Glades and Hendry counties. Five wells penetrate the Floridan aquifer and the rest penetrate shallow aquifers. Also included are analyses of samples collected at REPORT OF INVESTIGATIONS NO. 37 59 DISTANCE.IN FEETFROM DISCHARGING WELL 0-- --n----10.X1-..0--- i ,o -0 0 1oooo 3oOo0 C TEST B TEST E Computation based on: Computation based on: T. 130,000 gpd per foot T. 1,055,000 gpd per foot SS-0.15 S-0.15 t 6 months of pumping t=6 months of pumping '4--I--- -- 4--- ___ __ _ W TEST C TEST F SComputation based on: Computation based on: 67 T-125,000 gpd per foot T.555000 gpd per foot SS-0.15 S-0.15 t-6months of pumping t=6 months of pumping TESTD TEST G Computation based on: 5 Computation based on: T-.120,000 gpd per foot T /275,000 gpd per foot S-0.15 / .015 St-6 months of pumping / -6 months of pumping Figure 23. Graphs showing drawdowns expected at different distances from a well pumped at selected rates in each of six test areas. multiple depths in a few wells, which indicate the change in quality of water at different depths in certain aquifers. In Glades and Hendry counties the water from the Floridan aquifer generally is highly mineralized, except in northwestern Glades County. Most of the mineralization is due to chloride salts, which suggests seawater contamination. The amount of mineraliza- tion differs with the depth of well, the well construction, and the location of the well. Some zones in the Floridan aquifer contain fresher water than others, but in general the deep parts of the aquifer yield water that is more saline than the shallow zones. TABLE 0. Analyses Of Water From Wells In Glades And Hendry Counties (Analymes by U. S. Geological Survey. Chemical constituent. are expressed in part per million,) GLADES COUNTY Hardnees as CaCO, 22 11 667 ...... ...... ...... 118 108 265 .. 848 250 1880 7.7 .. 8-. -51 814 .. -.... ...... 115 172 258 .- -.. 846 252 1,820 7.8 -. 8- 8-51 922 ..115 1 72.25....... 610 170 241 2 UB 48 1,80 7.6 _. 8- 4-561 1,071 .. .. ..... ..... ...... 118 172 280 ... 8. 2 284 1,250 7.6 8- 5-5.61 1,190 ... 18 0.01 741 4.7 111 172 280 0.2 d: 880 832 24 1,40o 7.8 6 28 2-27-51 110 24 .40 ..... 129 18 140 5.5 890 56 218 .6 .9 884 885 66 1,880 7.2 20 27 7.-21-48 85 .......- .02 184 83 166 534 118 195 .- .2 004 470 32 1,540 7.8 80 7-22-48 75 .*... .10 108 40 241 528 129 268 ... .0 1,041 422 0 1,790 7.7 45 28 8-28-48 17 ...- .... .08 156 18 06 484 79 75 .- 8.8 681 448 46 1,090 7.4 65 8-28-48 47 .. .... .05 144 12 175 468 10 280 ..- 852 409 26 954 7.0 90 8-28-48 63 ... .1. .0156 17 88 476 88 112 ... 02 691 460 70 1,150 7.1 42 29 8-81-48 4 .06 ..... 174 1 185 464 154 *218 _- 9.6 950 562 180 1,610 7.8 00 9- 1-48 51 .... .07 78 86 201 884 98 258 ... 1 868 842 28 1,580 7.4 20 9- 1-48 75 ...... .. ...... ... ..... ........... 3874 .. 270 -- ... 1,600 7.4 - 98 12-10-58 86 76 28 .20 0.97 49 12 9.2 1.2 218 4.5 11 .1 .1 227 172 0 864 7.0 7 201 11-25-58 642 79 11 .00 .27 50 40 820 12 166 298 888 1.5 .0 1,260 290 154 2,070 7.7 4 212 10-12-58 87 .... 12 ...... 1.5 148 6.2 81 1.8 358 87 50 .4 2.8 661 895 102 812 7.2 90 227 12-10-58 45 78 88 .04 .14 89 120 514 29 802 140 1,040 .1 .8 2,800 716 468 3,890 7.4 8 TABLE 6. (Continued) HENDRY COUNTY 8 12-10-53 10 77 6.1 0.06 1.3 123 1.2 21 1.2 880 12 33 0.1 0.1 410 312 0 687 7.5 84 4 4-28-48 90 .... .0 144 10 62 512 17 80 .4 -_ 566 488 18 .- 7.1 22 4-28-48 107 78 .94 .94 144 23 49 540 2.8 78 .4 -- 566 454 6 .. 7.1 15 5 12-10-58 9 75 6.4 .92 1.8 45 2.4 28 1.8 162 12 28 .1 .1 297 122 0 886 6.8 460 14 4-24-48 815 .. .28 66. 88 242 860 126 282 .0 926 298 8 7.5 12 17 8-22-48 601 ... .... .0 70 51 852 122 3851 480 2.4 1.2 1,870 884 284 2,800 7.1 8 20 6-16-42 50 79 ... ... ...... 122 11 45 440 2.9 59 ..- .1 457 860 0 888 - 21 6-17-42 46 .. -- -.. ...... 126 .12 89 466 1 47 -- .1 455 864 0 828 .. - 61 11-24-68 80 77 20 .21 .40 84 80 88 1.0 406 4.0 54 .8 .0 468 888 0 761 7.6 28 156 11-24-58 90 77 14 .01 .24 62 49 880 1.8 188 292 472 1.2 .0 1,400 856 248 2,260 7.6 4 168 11-24-658 68 77 52 .84 .44 108 12 40 8.7 424 16 85 .8 .0 710 819 0 747 7.6 18 200 12-10-58 70 75 26 .07 .21 100 15 89 2.2 416 14 40 .1 .1 470 811 0 747 7.5 45 276 11-24-58 44 78 21 .04 .16 174 12 85 1.6 568 85 128 .0 .1 798 484 22 1,250 7.1 80 278 12-10-58 790 88 14 .03 .11 118 95 514 16 150 245 1,080 1.8 .2 2,800 685 562 8,820 7.5 4 solution at time of analysis. FLORIDA GEOLOGICAL SURVEY The water in shallow aquifers in Glades and Hendry counties is generally of better quality than water in the Floridan aquifer, except near Lake Okeechobee, in the vicinity of LaBelle, and in the Devil's Garden area about 18 miles southwest of Clewiston. The concentrations of calcium and bicarbonate in the shallow aquifers are usually higher than in the artesian water, but the concen- trations of sodium, magnesium, sulfate, and chloride are usually lower. When the inventory of wells in the counties was made during 1952-53 and 1958-59, samples of water from most of the wells were analyzed for chloride content. Selected wells were resampled for partial chemical analysis, which included color, specific conductance, and total hardness. The results of the partial analyses of water samples from 205 wells are given in table 7; the results of the chloride-content analyses are listed in table 8. HARDNESS Hardness of ground water is due chiefly to dissolved calcium and magnesium salts. Water samples from the shallow aquifers in Glades and Hendry counties range from 13 to 755 ppm in total hardness. Samples from the Floridan aquifer range from 68 to 1,620 in hardness. Hardness values of more than 120 ppm denote hard water that usually requires some softening for general use. Most of the samples of extremely hard water also contain large amounts of sulfates and chlorides. Tables 6 and 7 show the total hardness as CaCO, in water samples from wells in the two counties. TOTAL DISSOLVED SOLIDS The mineral matter that remains after a quantity of water is evaporated is approximately equal to the total dissolved solids in the water. Water from the Floridan aquifer generally contains more dissolved solids than water from shallow aquifers. The total dissolved-solids content in ground water in Glades and Hendry counties ranges from 41 to 4,100 ppm in the shallow aquifers and from 340 to 5,300 ppm in the Floridan aquifer. Total solids should be below 500 ppm to meet U. S. Public Health Service standards (1946). Water containing more than 1,000 ppm probably contains enough objectionable constituents to impart a noticeable taste and make the water unsuitable for many purposes. REPORT OF INVESTIGATIONS NO. 37 63 TABLE 7. Partial Analyses of Water from Wells in Glades and Hendry Counties GLADES COUNTY 1 5- 6-53 120 860 430 1,4300 60 0 3 5- 6-53 48 1;300 255 2,240 90 S5 30 26 63 S 4-29-53 96 77 610 288 1,020 24 0 4-29-53 173 320 284 540 25 S1 5 5 1 5- -3 35 38 3 3 2 5- 8-53 804 12,400 645 4,020 9 12 5- 6-53 120 81 860 430 1,430 60 13 5- 6-53 48 80 1;,00 255 2,240 90 26 4-29-53 120 380 276 633 19 37 4-29-53 96 77 610 288 1,020 24 40 4-29-53 173 320 284 540 25 42 4-29-53 102 75 350 232 579 19 45 4-29-53 112 76 570 330 950 35 47 4-29-53 106 79 200 159 331 25 48 5- 1-53 325 77 380 236 630 22 49 5- 1-53 500 79 1,100 380 1,850 20 50' 1-53 85 76 310 186 511 30 52 5- 1-53 491 81 1,100 310 1,780 110 53 5- 1-53 495 80 1200 330 2,010 55 55 5- 1-53 62 -7 430 146 722 11 56 4-30-53 700 79 410 170 688 28 57 4-30-53 22 73 130 86 216 18 58 4-30-53 608 76 340 156 562 30 59 5- 1-53 593 400 180 670 45 60 5- 1-53 30 0 14 69 50 66 5- 1-53 25 200 134 339 65 71 4-29-53 34 75 690 300 1,150 28 73 4-29-53 22 76 450 228 754 20 76 4-29-53 410 76 430 266 722 18 77 4-29-53 21 75 45 14 78 99 79 5-13-53 70 74 80 40 136 75 s0 4-29-53 25 765 381 111 10 83 7- 8-53 618 7 350 68 580 7 85 5- 1-53 47 1 45 13 77 55 86 5- 1-53 300 76 340 210 568 25 90 5- 1-53 35 380 186 625 25 93 5- 1-53 86 2200 180 368 20 94 5- 1-53 46 75 340 308 569 14 98 5- 1-53 55 350 276 575 34 102 5- 1-53 41 380 190 636 55 106 5- 1-53 25 77 350 102 585 110 109 5- 1-53 5006 870 205 1,450 10 110 5- 1-53 508 78 1,100 160 1,800 19 112 5- 1-53 50 74 400 204 662 60 116 5- 1-53 750 -_ 1.300 545 2,250 22 118 5- 1-53 17 75 240 190 404 220 122 5- 1-53 70 380 132 634 110 123 5- 1-53 1,200 5,300 725 8,780 25 126 5- 1-53 25 75 320 228 534 180 128 5- 1-53 100 75 540 364 893 90 130 5-13-53 162 74 520 210 873 45 136 5- 6-53 85 74 1,500 240 2,510 45 139 5- 6-53 86 75 810 185 1,350 55 FLORIDA GEOLOGICAL SURVEY TABLE 7. (Continued) 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 5- 6-53 4-30-53 4-30-53 5- 6-53 4-29-53 5-13-53 5-13-53 5-13-53 5- 6-53 5- 6-53 5-13-53 5-13-53 5- 8-53 5-13-53 5- 8-53 5- 8-53 5- 8-53 5- 8-53 5- 8-53 4-29-53 4-29-53 50 40 e00 32 56 600 48 30 6 20 102 26 52 40 105 110 101 100 73 186 68 68 850 642 65 65 40 1,500 1,250 44 20 26 100 42 45 53 500 5 0 o .0 s" S C. 0- E g > E IW 0 3., n a a 80 79 74 77 81 79 79 86 81 __ 76 79 75 80 72 920 1,600 2,500 430 4,100 870 1,100 2,200 620 960 3.400 640 950 970 1,100 790 1,100 3,100 1,500 430 440 660 1.400 1,200 540 1,200 3,800 550 4.800 1.100 470 570 240 2.600 360 1,000 1,600 1,500 65 360 245 685 144 550 305 755 570 340 485 460 374 345 375 260 210 310 350 230 338 340 226 470 290 476 450 730 380 1,620 435 352 426 158 730 242 475 575 430 22 ,u 0 1,40 1,760 3,70 go 070 C .O 1,540 2.640 4,110 723 6.770 1,450 1,760 3,750 1.030 1,600 5,650 1,070 1,580 1,610 1,800 1,310 1,830 5,110 2,500 716 726 1,100 2,390 2.000 894 1,960 6,400 928 7,980 1,760 776 947 402 4.300 598 1,660 2,610 2,440 107 0 45 35 19 220 60 30 110 45 75 60 45 40 60 75 50 40 55 90 60 50 40 65 40 12 200 110 15 65 20 5 100 110 75 30 70 45 90 10 60 HENDRY COUNTY 2 4-30-53 650 80 1.300 330 2,210 7 12 5- 8-53 105 _. 670 394 1,120 60 15 5- 8-53 130 370 214 624 45 17 4-30-53 601 81 1,300 370 2,230 14 19 5- 7-53 80 590 336 979 50 REPORT OF INVESTIGATIONS No. 37 65 TABLE 7. (Continued) u o o 0 2Y u u a fa ao 0w - *w o? .^ w 00 _ Ei __ 0B t~~7 S 14; o '8 ^ iE a Q Q i p __ 46 51 52 54 55 58 60 62 63 66 71 72 74 75 77 79 80 81 83 84 85 87 88 89 90 92 97 103 105 106 107 108 111 112 114 115 116 119 120 121 127 128 131 136 140 141 142 145 149 5- 7-53 5- 7-53 5- 7-53 5- 1-53 5- 7-53 5- 7-53 5- 7-53 4-29-53 4-29-53 4-29-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 4-29-53 4-29-53 4-29-53 5- 1-53 4-29-53 4-30-53 4-29-53 5- 1-53 4-29-53 4-29-53 4-29-53 4-29-53 4-29-53 4-29-53 4-29-53 4-29-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 1-53 5- 7-53 5- 1-53 5- 1-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 1,465 68 1,300 100 50 995 123 580 115 300 715 820 125 85 250 750 90 700 1,536 30 390 69 117 95 664 800 208 122 45 60 800 700 137 26 700 46 76 100 100 68 74 80 80 83 83 79 84 82 79 82 79 76 84 84 80 76 79 83 79 78 80 87 78 78 76 78 78 82 81 78 84 86 76 80 79 78 75 81 76 2,300 2,400 290 2,900 920 660 2,300 430 1,000 470 730 1,800 1,900 1,100 2,200 640 500 2,400 2,400 2,300 2,700 1,400 1,400 2,600 520 490 340 1,300 1,300 1,100 1,100 470 2,100 1,700 1,600 2,200 2,800 810 310 2,600 500 1,300 600 1,200 1,400 1,300 1,100 570 570 760 767 200 920 395 310 795 260 270 202 338 425 485 455 795 290 262 510 550 720 455 370 390 995 280 142 260 235 365 255 245 264 740 635 640 890 1,030 355 250 715 188 475 226 345 355 360 345 232 262 3,840 3,970 477 4,880 1,540 1,070 3,760 716 1,720 790 1,220 2,940 3,090 1,870 3,580 1,060 829 4,010 4,060 3,910 4,500 2,250 2,250 4,320 871 823 562 2,200 2,200 1,870 1,790 789 3,450 2,800 2,590 3,740 4,600 1,350 509 4,260 837 2,240 1,000 1,960 2,310 2,160 1,860 947 947 FLORIDA GEOLOGICAL SURVEY TABLE 7. (Continued) 0 1 I~~ .2 I 6 -4 0 > E Q 2S 2. 0 0 B 0 >2 o Ei ^ 0 60 S20 c |6 6. 0ca] __ a cj Q ^~C Q Q i Q 150 151 152 154 155 156 159 161 166 167 170 171 172 175 176 177 180 181 182 184 185 186 187 188 190 194 197 198 199 201 203 204 205 206 207 210 211 212 214 215 216 220 221 223. 224 225 227 236 241 4-30-53 4-30-53 4-20-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-52 4-30-53 4-30-53 5- 1-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 4-30-53 3-11-53 5- 7-53 5- 8-53 5- 8-53 4-30-53 4-30-53 5- 7-53 5- 7-53 5- 7-53 5- 7-53 5- 7-53 5- 7-53 5- 7-53 5- 7-53 5-12-53 5- 7-53 5- 7-53 5- 7-53 5-13-53 5- 8-53 5- 8-53 5- 8-53 5-13-53 5- 8-53 5-13-53 30 28 22 18 80 90 744 84 80 80 98 40 145 140 135 18 20 92 60 180 99 78 100 48 326 45 47 90 180 15 112 90 160 100 100 26 42 140 45 244 328 112 12 40 15 36 115 38 78 78 78 75 77 76 74 76 --. 74 75 72 77 75 310 500 680 1,300 1,300 1,300 1,900 470 540 1,300 790 540 830 570 650 1,600 360 290 740 620 590 430 370 520 390 920 590 570 470 460 430 430 670 310 820 1,000 1,400 400 1,800 2,900 1,700 1,000 1,100 590 640 470 650 490 610 168 296 220 445 370 365 330 206 242 350 355 132 330 236 180 345 252 218 285 244 114 290 202 296 88 165 276 248 412 224 212 152 292 248 200 420 530 208 260 610 250 160 180 316 172 200 156 156 148 508 846 1,130 2,230 2,220 2,160 3,100 790 907 2,090 1,320 907 1,390 941 1,090 2,700 596 485 1,230 1,020 977 723 613 873 654 1,540 980 947 787 771 711 713 1,110 523 1,360 1,680 2,390 673 3,000 4,850 2,750 1,590 1,870 987 1,070 775 1,090 823 1,020 19 22 15 16 15 6 22 27 21 16 25 65 20 15 35 45 110 25 27 50 21 27 40 100 45 45 55 100 70 120 55 120 60 55 65 100 30 45 40 50 55 55 220 50 80 55 100 45 REPORT OF INVESTIGATIONS NO. 37 TABLE 7. (Continued) 248 250 252 258 263 265 268 269 270 271 272 273 274 275 278 5- 8-53 5- 8-53 5- 8-53 5-12-53 5-12-53 5-12-53 4-30-53 4-30-53 5- 7-53 5-12-53 5- 7-53 5- 8-53 5-13-53 5- 1-53 7- 7-53 .6 0. '0 .0 C: o, II A 4 - >B M gg 610 740 580 550 1,200 700 430 1,900 520 470 1,700 1,700 580 1,700 2,200 0 cu '6) 0 gEh 0 Cn 0. E2 a m 1,010 1,230 972 914 1,990 1,170 708 3,170 860 774 2,800 2,850 962 2,850 3,700 SPECIFIC CONDUCTANCE Specific conductance is a measure of the ability of water to conduct an electric current. Water containing a low mineral content is resistant to the flow of electricity, whereas highly mineralized water conducts an electric current with relative ease. Therefore, the values for specific conductance can be used to estimate the concentration of dissolved solids in water. Figure 24 shows the relation of total dissolved solids in water samples to specific conductance where both values have been determined in the laboratory. The data show that the dissolved solids can be approxi- mated by multiplying the specific conductance by 0.6. Specific conductance is .usually higher in the deep -artesian water than in the water from the shallow aquifers; it reaches a maximum of more than 8,700 micromhos in well 123 in Glades County. In table 7 the values for total dissolved solids were estimated from specific conductance by multiplying by the 0.6 factor. 68 FLORIDA GEOLOGICAL SURVEY EXPLANATION SI a I J I DEEP ARTESIAN WELL WELL IN SHALLOW AOUIFER */- 4oo-i--i--i--i---- -- --- ---- -: -- -7 o 1000 .000 0-00 4.000 5,00 SPECIFIC CONDUCTANCE (MICRO.HOSAT 25C) Figure 24. Graph showing the relation between specific conductance and total dissolved solids in water samples from Glades and Hendry counties. ,1000,000 -0 4-000 5-000 HYDROGEN-ION CONCENTRATION (pH) The pH is a measure of the hydrogen-ion concentration and indicates whether the water is acid or alkaline. On a scale of 0 to 14, pH values higher than 7.0 indicate alkalinity and values lower than 7.0 indicate acidity. All samples analyzed, except one, had pH values of 7.0 or greater; the sample from well 22 in Glades County had a pH of 6.9. The measured pH values are shown in table 6. IRON (Fe) Water containing more than 0.3 ppm of iron will stain plumbing fixtures, clothes, and other objects with which it comes in contact. High concentrations of iron also cause the water to have a disagreeable taste. Iron in a clear ground-water solution is in the ferrous state until the water is exposed to the oxygen in the atmosphere, then the iron is oxidized to the ferric state and precipitates as the insoluble hydroxide or oxide of iron. The iron precipitate may then be removed by filtration. Water samples from the artesian aquifer contained less than 0.3 ppm of iron. The iron content of water from the shallow aquifers differs from place to place and at different depths within the aquifer. It ranged from 0.11 to 1.5 ppm (table 6). REPORT OF INVESTIGATIONS NO. 37 CALCIUM (Ca) AND MAGNESIUM (Mg) Dissolved calcium and magnesium salts are responsible for most of the hardness of water. Much of the water-bearing material underlying Glades and Hendry counties is composed of limestone and a lesser amount of dolomite. These carbonate rocks are the sources of calcium and magnesium in the ground water in the area. The concentration of calcium ranged from 42 to 136 ppm in water samples from the Floridan aquifer and from 49 to 174 ppm in water samples from the shallow aquifers. The concentration of magnesium ranged from 36 to 105 ppm in the Floridan aquifer and from 1.2 to 120 ppm in the shallow aquifers. The shallow ground water usually contains less magnesium than the artesian water and the amount of magnesium is usually less than the calcium. An exception is shown in the analyses of water from well 227 in Glades County northwest of Clewiston and from well 276 in Hendry County in Clewiston (table 6). The wells are about 4 miles apart and about 45 feet deep. The chemical analyses of the samples show wide differences in chloride content, total dissolved solids, sodium, calcium, and magnesium. The ratio of magnesium to calcium in well 227 is of interest; the content of magnesium is considerably higher than that of calcium, unlike other samples from the shallow aquifer. As sea water contains more magnesium than calcium, this may indicate the presence of sea water which was trapped in the aquifer during high stands of the sea in Pleistocene time. No dolomitic limestones are known to occur in the shallow materials, thus discounting the solvent action of ground water on the shallow materials as the source of magnesium. The high chloride content of water is further indication of contamination by sea water. SODIUM (Na) AND POTASSIUM (K) The quantity of sodium plus potassium in ground water in Glades and Hendry counties ranges from 10.4 to 543 ppm in the shallow aquifers and from 145.5 to 530 ppm in the Floridan aquifer; the concentration of sodium greatly exceeds that of potassium. Moderate amounts of these constituents have no effect on the palatability of drinking water, but large amounts render the water unsuitable for most uses. The ratio of the quantity of sodium to the total quantity of sodium, calcium, and magnesium is important when the water is to be used for irrigation. Large FLORIDA GEOLOGICAL SURVEY quantities of sodium tend to decrease the permeability of soils, and water containing more than 50 percent sodium may injure the soil and crops. Figure 25 shows the suitability of water for irrigation, as determined by Wilcox (1948, p. 25-26) and utilized by Visher (1952, p. 15-17) in an arid area. Most of the water samples from the shallow aquifers are in the range from excellent to permissible, but many of the samples from the Floridan aquifer are in the doubtful or unsuitable range. However, the chart assumes little or no flushing of the soil by rainfall. In an area of plentiful rainfall, such as south Florida, the sodium content of the soil probably would not accumulate in quantities harmful to most crops. BICARBONATE (HCO,) The amount of bicarbonate in the ground water in Glades and Hendry counties ranges from 138 to 563 ppm in the shallow aquifers and from 109 to 166 ppm in the Floridan aquifer. The bicarbonate results from the solvent action of ground water containing carbon dioxide gas on carbonate rocks. Much of the bicarbonate can be readily removed by relatively simple water treatment. SULFATE (SO,) Concentrations of sulfate in ground water in Glades and Hendry counties range from 1 to 292 ppm in the shallow aquifers and from 126 to 351 ppm in the Floridan aquifer. The sulfate radical is not very important in domestic water supplies unless it exceeds 500 ppm, in which case it may have a laxative effect. The U. S. Public Health Service recommends that public water supplies contain not more than 250 ppm of sulfate. Some sulfate compounds in water cause hardness that is difficult to reduce by treatment. CHLORIDE (Cl) Water containing chloride in excess of 250 ppm is considered by the U. S. Public Health Service to be unsuitable for public drinking supplies, except in areas where better quality water is not available. Water containing more than 750 ppm of chloride may damage many plants and shrubs. Chloride concentrations in ground water in Glades and Hendry counties range from 7 to 2,280 ppm in the shallow aquifers and from 34 to 4,240 ppm in the Floridan aquifer. REPORT OF INVESTIGATIONS NO. 37 HE HENDRY EXCELLENT GOOD DOUBTFUL UNSUITABLE 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 SPECIFIC CONDUCTANCE (MICROMHOS, AT 25C) Figure 25. Graph showing the suitability of ground water for irrigation. (after Wilcox 1948, p. 25-23) High-chloride water is corrosive and may rust holes in the casing through which subsurface leakage from artesian wells can occur. Chloride cannot be removed by ordinary water treatment. Water samples for chloride-content analysis were obtained from most of the wells inventoried in the two counties, and the analytical results are listed in table 8. Figure 26 shows the chloride content FLORIDA GEOLOGICAL SURVEY I 278 S 8i5 *872 4 29E R 29E R0OE- EXPLANATION Chloride content 4 0 O (ports per million) O I No. 0-100 e epth,in feet 3 101-250 T 47- 251-500 s O 501-1000 _ 1001-2000 T I + TI More than 2000 sI SCALE IN MILES ._ 2 0 2 4 6 8 10 R31E DORE HAVEN QDES COUI UNTY *1039 HENRY J. COUNTY R32E R33E Figure 26. Glades and Hendry counties showing the chloride content of water samples from wells tapping the Floridan aquifer, 1952-53, 1958. LAKE ECHOBEE S 4I CLE'WSTON R34E v REPORT OF INVESTIGATIONS NO. 37 73 of water samples from wells tapping the Floridan aquifer in these counties. Most of the data shown were obtained during 1952-53; additional information was obtained during 1958 in more recently established agricultural and grazing lands. The data in figure 26 suggest that the deeper wells generally yield the water of poorest quality. Potable water is available from the Floridan aquifer in central Glades County in the vicinity of Palmdale, and good-quality water can be expected northward and northwestward from central Glades County into Highlands County. Also, wells reportedly ranging in depth from 390 to 450 feet immediately north of LaBelle yield potable water. These wells probably tap the uppermost limestone layers of the Floridan aquifer. A group of artesian wells 8 miles east of LaBelle and three wells near the northern boundary of Glades County yield water that contains less than 250 ppm of chloride. It is possible, however, that increased use of water in those areas may cause a slow deterioration of the quality as a result of upward movement of water of higher chloride content within the aquifer. The data shown in figure 27 indicate that the shallow aquifers in Glades County yield water of low chloride content except in areas adjacent to Lake Okeechobee. Figure 28 shows chloride data for EXPLANATION I 2510-00 S "ENU. I So L romwels t g s w uirs, 1 501 000 .. .. ..... .. . o......... .3. -- - oOS COT !o sfA- 1.31 40. 1 .. ... .. . i I o '^ ,' : o. w ,*S ........ .,d~~f~b~ib~t., / f A %rA from wells tapping shallow aquifers, 1952-53. FLORIDA GEOLOGICAL SURVEY Figure 28. Part of eastern Glades County showing the chloride content of water samples from wells tapping shallow aquifers, 1952-53, 1959. the area north of Lakeport where there is a large concentration of shallow wells. It is apparent that most of the shallow water in the Lakeport area does not meet the standards for public supplies. Figure 29 is a map of Hendry County showing the chloride content of water samples from wells tapping shallow aquifers. The distribution of the chlorides suggests isolated sources of con- tamination by salty water. Figure 30 shows the chloride content of water from selected wells in the Clewiston area. FLUORIDE (F) The fluoride concentration in ground water in Glades and Hendry counties ranges from 0 to 1.2 ppm in the shallow aquifers and from 0.2 to 2.4 ppm in the Floridan aquifer. Minor quantities of fluoride in drinking water are beneficial in decreasing tooth decay among children (Black and Brown, 1951, p. 15). However, quantities in excess of 1.5 ppm may result in a condition known as dental fluorosis, a mottling of the tooth enamel in chlidren. SILICA (SiO,) The amount of silica in ground water in Glades and Hendry counties ranges from 6.1 to 56 ppm in the shallow aquifers and from 11 to 14 ppm in the Floridan aquifer. Silica content is of relatively REPORT OF INVESTIGATIONS No. 37 75 r-GLADES COUNTY - . f ,i I Figure 29. Henry County showing the chloride content of water samples the shallow aquifer. A concentration above 50 ppm is very undesirable in drinking water, because it may cause cyanosis in Hydrogen sulfide is found in much of the shallow water and all I i4 the deep artesian water of the area. Hydrog en sulfide causes a distinct taste and odor which has given the water the name "sulfur water." Hydrogen sulfide is not generally analyzed because it is a H e ulfu f e s o we B r -i COUNTYR30ER COUNT _; _ e EXPLA" TION in y Figure 29. Hendry County showing the chloride content of water samples from wells tapping shallow aquifers, 1952-53, 1958. little importance except in the formation of boiler scale, and was not determined in most analyses. NITRATE (NO.) Nitrate concentrations range from o to 1.2 ppm in the water from the artesian aquifer, and from 0 to 9.6 ppm in the water from distinct taste and odor which has given the water the name "sulfur water." Hydrogen sulfide is not generally analyzed because it is. a FLORIDA GEOLOGICAL SURVEY i ---- ~ ---- 1- ^ ^, ^ e 1 -261 262 1 250 4246 244 240 l 3 2 r, s 3 22 25 ) 253 5 225 Figure 30. Clewiston area showing the chloride content of water samples from wells tapping the shallow aquifers, 1952-53. volatile gas held in solution and much of it escapes upon exposure to air. Most of the gas can be removed by aeration. SALT-WATER CONTAMINATION In southern Florida the major causes of soal-water contami- gre Colewstn area htoewin the Grulf t of M water msamles nation of aquifers are as follows: (1) direct encroachment from surface salt-water bodies along coastal areas where the fresh-water head is not sufficient to retard encroachment; (2) upward leakage of relatively salty artesian water, under high pressure, through open well bores or across semiconfining layers; and (3) incomplete flushing of sea water that entered the aquifers during high-sea-level intervals of the Pleistocene Epoch when southern Florida was covered by the ocean. Direct encroachment: The only possible source of direct sea- water encroachment in Glades and Hendry counties is the Caloosahatchee River. The Ortona Lock is closed during extended dry periods and sea water from the Gulf of Mexico may move inland to the downstream side of the lock. However, the banks and the riverbed along most of the reach downstream from Ortona are composed of relatively impermeable clay and marl, which tend to prevent lateral or downward seepage from the channel. Also, ground-water levels adjacent to the river usually are considerably higher than the river stage (fig. 17), and the normal direction of ground-water flow is toward the river. Therefore, direct sea-water encroachment into aquifers in Glades and Hendry counties is negligible. Upward leakage: In most of Glades and Hendry counties the deep parts of the Floridan aquifer contain water that is saltier than water in the shallow parts. In some places thin zones REPORT OF INVESTIGATIONS NO. 37 containing fairly fresh water may underlie salty zones, but if the open-hole section of the well is deepened, additional zones containing salty water will be tapped (see table 4). In most areas of the two counties the pressure in the deep zones of the aquifer is greater than that in shallow zones. If a well is so constructed that its open bore section penetrates upper fresh zones and deeper salty zones, the deep salty water under high pressure can move upward through the well bore and enter the shallow fresh-water zone. The amount of interchange of water will depend upon the permeability of the rock and the pressure differential between the two zones. It appears, therefore, that well construction is an important factor in the quality of the water yielded by a well in the Floridan aquifer. Contamination by upward leakage within the Floridan aquifer probably is accelerated where the piezometric surface is lowered as a result of heavy discharge by wells. High pressure in deep zones will cause saline water to move upward into zones of fresh water that are tapped by wells. The high mineralization of the water from artesian wells in LaBelle and southwest of LaBelle shown in figure 31 may be due, in part, to the decline of the piezometric surface in this general area, as shown in figure 14. It is possible that the initial flowing wells drilled in this area yielded fresher water than that shown in figure 31. -------- I HENRY COUNTY soL BELLE s Sijr* j/,-. I I 327 75 EXPLANATION S3 t5 o na Chloride content 318 319 O s 76 (parts per million) 45115 89 292 ST Well No, 0 T Depthin feet 0o100 2 321 10 101 250 251-500 501-1000 ISCAL IN MILES 0 0 I 2 More than 1000 Figure 31. Part of northwestern Hendry County showing the chloride content of water samples from wells tapping deep and shallow aquifers, 1952-53, 1958. FLORIDA GEOLOGICAL SURVEY The salt-water contamination in the shallow aquifer in LaBelle was probably caused by upward and lateral leakage in the vicinity of wells penetrating the Floridan aquifer. Figure 32 shows the chloride content of water from shallow wells in and adjacent to LaBelle. Most of the shallow wells in LaBelle range in depth from 60 to 120 feet below the land surface and are developed in shelly limestone layers. The seven deep artesian wells within the populated area south of the Caloosahatchee River probably were drilled before 1930 (fig. 11). It was reported that casings in most of these wells were seated in a limestone layer at a depth of about 80 feet and that an open bore was drilled to 600-800 feet. The piezometric surface in these wells is at least 25 feet above the land surface, whereas the water level in the shallow wells is below the land surface. Therefore, direct connection probably exists between the open bore of the deep wells and the limestones below 80 feet in the shallow aquifer. Most of the deep wells in LaBelle are not in use or are used sparingly, so that the discharge valves are cut off for long periods. As a result, the pressure differential between the deep well bores and the shallow limestones is consistently high, and upward discharge into the shallow limestone occurs at a constant rate. Well 17 in LaBelle, immediately south of the Caloosahatchee River, taps the Floridan aquifer, and for many years was used as the central water supply for the town. Distribution lines extend from the well probably as far south as State Highway 80. These distribution lines are known to have developed leaks and the entire system is a probable source of local contamination of the shallow aquifer. The pattern of the chloride contours shown in figure 33 suggests that the five deep artesian wells (within the 400-ppm contour line) between the Caloosahatchee River and State Highway 80 and the subsurface water-distribution system from well 17 may be the principal sources of contamination. Further evidence to support this is shown by a comparison of the analyses of water samples from well 17 (602 feet deep) and well 156 (90 feet deep), 170 feet south of well 17, as shown in table 6. The analyses are nearly identical. The pattern of the distribution of the chloride contents and isochlor contours in figure 33 negates the possibility that the Caloosahatchee River is the source of contamination. The contour pattern shows that contamination extends beneath and across the river and further substantiates the conclusion that the river does not appreciably affect the drainage of the shallow aquifer. REPORT OF INVESTIGATIONS No. 37 Figure 32. LaBelle showing the chloride content of water samples from wells tapping the shallow aquifer, 1952-53. Much of the salt-water contamination in the shallow aquifer along the Caloosahatchee River west and southwest of LaBelle may be caused by conditions similar to those causing the contamination in LaBelle. The water level of well 112, a 45-foot well near the Lee County boundary, was 7.5 feet above the land surface in May FLORIDA GEOLOGICAL SURVEY I II LA BELLE II CITY LIMITS II I Figure 33. LaBelle showing (by isochlor lines) areas of equal chloride content of water from the shallow aquifer, 1952-53. 1958. This high water level is probably due to upward and lateral leakage from immediately adjacent artesian wells which have been capped at the surface and abandoned. Incomplete flushing: The high mineralization of. the water contained in the Floridan aquifer in southern Florida probably is due to connate sea water which remained in the materials when they were deposited, or to sea water that entered the aquifer when REPORT OF INVESTIGATIONS NO. 37 much of peninsular Florida was covered by the ocean during the Pleistocene Epoch. The shallow aquifers in Glades and Hendry counties also were filled with sea water when the area was last covered by the ocean, but since the seas receded rainfall has been flushing salts from the shallow aquifers. Flushing has been more extensive in the shallow materials than in the Floridan aquifer, but Love (Parker and others, 1955, p. 818) indicated that saline water and the residual salts have never been completely flushed in most of the Everglades, particularly near the borders of Lake Okeechobee. Figures 27 and 28 show the high salinity of the shallow ground water adjacent to Lake Okeechobee. Flushing of salts would be most rapid where the infiltration of rainfall is rapid and where ground-water movement is not impeded. The rather uniformly low permeability of the shallow sediments may be one of the chief reasons for the saline ground water along the borders of Lake Okeechobee. Also, the low ground-water gradient throughout the area may be an important factor in the slow flushing process. Most of the potential aquifer recharge by rainfall in the area probably is lost by sheet flow and evapo- transpiration, and apparently only minor quantities can infiltrate to the permeable sections. Differences in permeability may partly account for the variations of chloride content in areas where upward leakage from the Floridan aquifer is not a factor. UTILIZATION OF GROUND WATER Ground water in Glades and Hendry counties is used for irriga- tion, public and domestic supplies, stock watering, and, to lesser extent, industries and air conditioning. IRRIGATION The quantity of ground water used for irrigation in Glades and Hendry counties far exceeds that used for other purposes. In addition to the huge sugar plantations that border Lake Okeechobee near Clewiston, large areas are devoted to the production of truck crops grown during late fall, winter, and spring. In areas near surface-water bodies irrigation is practiced by use of shallow ditches from the surface sources. Other areas, however, depend on ground-water sources. Water for irrigation is obtained from the Floridan aquifer and the shallow aquifers. The source used depends on the crops to be grown. Tomatoes and cucumbers will tolerate water with a FLORIDA GEOLOGICAL SURVEY fairly high concentration of dissolved solids, whereas beans and some other crops will not. Irrigation by use of shallow wells is a fairly recent development in the area and will probably increase. The largest increase in the use of irrigation water has taken place in Hendry County, south of LaBelle, and in the Big Cypress Swamp- Devil's Garden area. MUNICIPAL SUPPLIES LaBelle and Moore Haven are the only municipalities in the two counties that used ground water for public supplies in 1959. The supply for LaBelle was obtained from well 17, which penetrates the Floridan aquifer. The water was piped directly from the well through distribution lines to the consumers and received no treat- ment. The quality of the water is poor and most of the residents have resorted to drilling individual shallow wells. In the central part of LaBelle the shallow aquifer does not produce water of acceptable quality because of salt-water contamination (fig. 33). Chemical analyses of water samples in the LaBelle area indicate that ground water of good quality can be obtained away from the central part of the town, where the shallow water is low in chloride, relatively low in total dissolved solids, but high in hardness. The hardness can be reduced by treatment, and aeration and filtration will remove much of the iron and hydrogen sulfide present in solution. In 1959 the residents of LaBelle authorized a study to develop a public water supply from the shallow aquifer south of town. Moore Haven obtains its water supply from an 8-inch well drilled to a depth of 87 feet. A 5-horsepower deep-well turbine pump is capable of withdrawing 285 gpm from the well. Approximately 85,000 to 100,000 gallons of water are used daily by the town. This includes water for household use, industrial use, and lawn irrigation. Water treatment consists of aeration, reduction of hardness, and chlorination. None of the other communities in the area are supplied by public ground-water systems. In agricultural areas and small population centers such as Palmdale, Lakeport, and the outskirts of LaBelle, nearly every home has its individual water supply. A similar situation exists in suburban areas west and southeast of Clewiston. The city of Clewiston obtains its municipal supply from Lake Okeechobee. REPORT OF INVESTIGATIONS NO. 37 OTHER USES A small quantity of ground water is used for industrial and cooling processes, and a few commercial establishments in Clewiston operate wells for air conditioning. A shallow well is used in running condensers at the ice plant at Moore Haven. Several packing houses in the farming areas use a considerable quantity of ground water in the washing, processing, and packing of truck crops. These wells are operated for only a few weeks during the year. Ground water is used also for stock watering. SUMMARY The most productive aquifer in Glades and Hendry counties is the Floridan aquifer, which yields water by natural flow to most parts of the area. Wells penetrating this aquifer range in depth from 400 feet to more than 1,200 feet and generally yield 200 gpm or more. The chloride concentration in water from wells tapping the artesian aquifer at depths of 400 to 700 feet ranges from 40 ppm to more than 2,000 ppm. The aquifer underlying Glades County in the vicinity of Lake Okeechobee yields water with a chloride content ranging from 700 to more than 1,200 ppm. Artesian water containing less than 100 ppm of chloride, can be obtained in north- western and northern Glades County. In general, the chloride content of the water increases southward and southeastward. Permeable zones in the aquifer occur down to more than 1,200 feet. Throughout most of the area the lower limestones yield highly mineralized water, except in northwestern and northern Glades, County where relatively fresh water can be obtained in the deep part of the aquifer. Shallow sources of ground water are being developed in both Glades and Hendry counties, especially in those areas where the artesian water is highly mineralized. Wells penetrating shallow aquifers generally range in depth from 50 feet to more than 300 feet. The permeable limestone of the Tamiami Formation in southern Hendry County is the most productive shallow aquifer in the area. Wells penetrating this aquifer range in depth from about 40 feet in areas a few miles east of Immokalee to about 120 feet or more south of the Devil's Garden. The lateral extent and the total thickness of this aquifer cannot be determined with present data; however, the aquifer is known to extend as far north as the Felda FLORIDA GEOLOGICAL SURVEY area, but has not been noted in wells in the immediate Immokalee area. The aquifer apparently dips to the east and to the south. Six-inch wells penetrating this limestone aquifer yield good quality water at a rate of more than 1,000 gpm with little draw- down. Water levels are within a few feet of the land surface, and pumping costs are relatively low. In central and northern Hendry County and in Glades County the shallow aquifers are composed of thin local limestones and shell beds in the Tamiami and Hawthorn Formations. These aquifers range in depth from 50 feet to about 175 feet and yield moderate amounts of water. The water usually contains less than 400 ppm of chloride, except in areas adjacent to Lake Okeechobee and along the Caloosahatchee River westward from LaBelle. In and southwest of LaBelle the shallow aquifer is contaminated by artesian water under high pressure leaking upward along open-well bores and laterally into permeable beds of low pressure. Quantitative tests show that the coefficient of transmissibility of the shallow aquifers ranges from 70,000 gpd/ft to 1,070,000 gpd/ft, and that the coefficient of storage ranges from 0.00015 to 0.0014. REPORT OF INVESTIGATIONS NO. 37 REFERENCES Applin, E. R. (also see Applin, P. L.) 1945 (and Jordan, Louise) Diagnostic Foraminifera from subsurface formations in Florida: Jour. Paleontology, v. 19, no. 2, p. 129-148. Applin, P. L. 1944 (and Applin, E. R.) Regional subsurface stratigraphy and struc- ture of Florida and southern Georgia: Am. Assoc. Petroleum Geologists Bull., v. 28, no. 12, p. 1673-1753. 1951 Preliminary report on buried pre-Mesozoic rocks in Florida and adjacent states: U. S. Geol. Survey Circ. 91. Bishop, E. W. 1956 Geology and ground-water resources of Highlands County, Florida: Florida Geol. Survey Rept. Inv. 15. Black, A. P. 1951 (and Brown, Eugene) Chemical character of Florida's waters: Florida State Board Cons., Div. Water Survey and Research Paper 6. Brown, Eugene (see Black, A. P.) Clapp, F. G. (see Matson, G. C.) Cole, W. S. 1942 Stratigraphic and paleontologic studies of wells in Florida: Florida Geol. Survey Bull. 19. 1944 Stratigraphic and paleontologic studies of wells in Florida: Florida Geol. Survey Bull. 20. Cooke, C. W. (also see Parker, G. C.) 1915 The age of the Ocala limestone: U. S. Geol. Survey Prof. Paper 95-I, p. 107-117. 1929 (and Mossom, Stuart) Geology of Florida: Florida Geol. Survey 20th Ann. Rept., p. 29-227. 1936 (and Mansfield, W. C.) Suwannee limestone of Florida (ab- stract): Geol. Soc. America Proc. (1935), p. 71-72. 1945 Geology of Florida: Florida Geol. Survey Bull. 29. 1952 Sedimentary deposits of Prince Georges County, Maryland, and the District of Columbia: Maryland Dept. Geology, Mines and Water Resources Bull. 10. Dall, W. H. 1892 Contributions to the Tertiary fauna of Florida, with special reference to the Miocene silex beds of Tampa and the Pliocene beds of the Caloosahatchee River: Wagner Free Inst. Sci. Trans., v. 3, pt. 2. Davis, J. H., Jr. 1943 The natural features of southern Florida, especially the vegeta- tion, and the Everglades: Florida Geol. Survey Bull. 25. FLORIDA GEOLOGICAL SURVEY DuBar, J. R. 1958 Stratigraphy and paleontology of the late Neogene strata of the Caloosahatchee River area of southern Florida: Florida Geol. Survey Bull. 40. Ferguson, G. E. (see Parker, G. G.) Hantush, M. C. 1955 (and Jacob, C. E.) Nonsteady radial flow in an infinite leaky aquifer: Am. Geophys. Union Trans., v. 36, no. 1, p. 95-100. 1956 Analysis of data from pumping tests in a leaky aquifer: Am. Geophys. Union Trans., v. 37, no. 6, p. 702-714. Heilprin, Angelo 1887 Explorations on the west coast of Florida and in the Okeechobee wilderness: Wagner Free Inst. Sci. Trans., v. 1. Hendry, C. W., Jr. 1957 (and Lavender, J. A.) Interim report on the progress of an inventory of artesian wells in Florida: Florida Geol. Survey Inf. Circ. 10. Jacob, C. E. (see Hantush, M. C.) Johnson, L. C. 1888 The structure of Florida: Am. Jour. Sci., ser. 3, v. 36, p. 230-236. Jordan, Louise (see Applin, E. R.) Klein, Howard (see Schroeder, M. C.) Lavender, J. A. (see Hendry, C. W., Jr.) Love, S. K. (see Parker, G. G.) MacNeil, F. S. 1944 Oligocene stratigraphy of southeastern United States: Am. Assoc. Petroleum Geologists Bull., v. 28, no. 9, p. 1313-1354. Mansfield, W. C. (see Cooke, C. W.) Matson, G. C. 1909 (and Clapp, F. G.) A preliminary report on the geology of Florida: Florida Geol. Survey 2d Ann. Rept., p. 25-173. 1913 (and Sanford, Samuel) Geology and ground waters of Florida: U. S. Geol. Survey Water-Supply Paper 319. Meinzer, O. E. 1923 The occurrence of ground water in the United States, with a discussion of principles: U. S. Geol. Survey Water-Supply Paper 489. Mossom, Stuart (see Cooke, C. W.) REPORT OF INVESTIGATIONS No. 37 Parker, G. G. 1944 (and Cooke, C. W.) Late Cenozoic geology of southern Florida, with a discussion of the ground water: Florida Geol. Survey Bull. 27. 1951 Geologic and hydrologic factors in the perennial yield of the Biscayne aquifer: Am. Water Works Assoc. Jour., v. 43, no. 10, p. 817-834. 1955 (and Ferguson, G. E., Love, S. K., and others) Water resources of southeastern Florida, with special reference to the geology and ground water of the Miami area: U. S. Geol. Survey Water- Supply Paper 1255. Puri, H. S., 1953 Contributions to the study of the Miocene of the Florida Panhandle: Florida Geol. Survey Bull. 36. Richards, H. G. 1945 Correlation of Atlantic Coastal Plain Cenozoic formations; a discussion: Geol. Soc. of America Bull., v. 56, p. 401-408. Sanford, Samuel (see Matson, G. C.) Schroeder, M. C. 1954 (and Klein, Howard) Geology of the western Everglades area, southern Florida: U. S. Geol. Survey Circ. 314. Sellards, E. H. 1912 The soils and other residual material of Florida: Florida Geol. Survey 4th Ann. Rept., p. 7-79. 1919 Geologic section across the Everglades, Florida: Florida Geol. Survey 12th Ann. Rept., p. 67-76. Stringfield, V. T. 1936 Artesian water in the Florida peninsula: U. S. Geol. Survey Water-Supply Paper 773-C, p. 115-195. Theis, C. V. 1938 The significance and nature of the cone of depression in ground- water bodies: Econ. Geology, v. 33, no. 8, p. 889-902. U. S. Public Health Service 1946 Public health reports, reprint 2697. Vernon, R. O. 1951 Geology of Citrus and Levy counties, Florida: Florida Geol Sur- vey Bull. 33. Visher, F. N. 1952 Reconnaissance of the geology and ground-water resources of the Pass Creek Flats area, Carbon County, Wyoming, with a section on the chemical quality of the ground water by W. H. Durum: U. S. Geol. Survey Circ. 188. Wilcox, L. V. 1948 The quality of water for irrigation use: U. S. Dept. Agriculture Tech. Bull. 962. FLORIDA GEOLOGICAL SURVEY WELL LOGS Glades County WELL 22 NWYNW% sec. 29, T. 38 S., R. 34 E. Depth, in feet,- Material below land surface No samples _-- __--- 0- 65 Tamiami Formation Marl, gray, sandy, phosphatic; fragments of echinoids and Pecten ---__-__ 65 110 No samples --._--.__.__ ._-- .... ___ --_ .....- 110- 188 Hawthorn Formation Clay, dark-green, plastic; mollusk fragments ----------- 188 Clay, dark-green, sandy (coarse), phosphatic; pelecypods numerous, mostly Pecten and Area -_.---__ 188 -314 Clay, olive-drab, sandy, shelly, phosphatic ___.. --__... 314- 337 No samples ____ _______ 337 346 Clay, light-green, shelly, plastic; and olive-drab sandy, phosphatic, shelly clay marl -__ .- -._...-- ... 346 418 Clay, dark-green, plastic; phosphorite pebbles and mollusk fragments __ 418 465 Clay, gray, phosphatic; mollusk fragments ...--_- 465-480 Limestone, white, hard, dense, phosphatic; mollusk fragments .__ _____ 480 505 Gravel; phosphorite pebbles, brown, up to 8 mm in diameter; some limestone as above 505- 516 Clay, tan, plastic; many small particles of dark phos- phorite _____ __516 537 Clay, tan, plastic; many small particles of phosphorite --. 537- 575 Clay, dark-green, quartz sand, phosphorite pebbles; some gray sandy, phosphatic limestone ...__ __ _..._.. 575- 605 Tampa (?) Formation Limestone, cream, hard, porous, granular, slightly phos- phatic, and some sand ______ 605 620 Ocala Group Limestone, cream, foraminiferal coquina, soft, porous, chalky; Lepidocyclina ocalana __ 620 667 Limestone, cream, foraminiferal coquina, soft, porous,. granular; Operculinoides _- 667-814 Limestone as above but fewer foraminifers __ 814- 854 Avon Park Limestone Limestone, tan, hard, porous; numerous echinoids of Peronella type 854-888 REPORT OF INVESTIGATIONS NO. 37 Limestone, light-tan, hard, porous, granular; Dictyoconus cookei, Coskinolina floridana, and Peronella_ 888- 958 Limestone, tan, hard, granular, porous; some white, soft, chalky limestone; Spirolina coryensis ..___ ---- --.-- -... 958- 1022 Limestone, tan, hard, granular; numerous Coskinolina floridana ______. ..____...___ ----.......___.__. 1022- 1134 Lake City Limestone Limestone, light-brown, hard, calcitic, granular, porous; some gray dense limestone and brown porous, finely crystalline, dolomitic limestone ...__._.__ 1134- 1215 WELL 27 NEYNW% sec. 25, T. 39 S., R. 33 E. Depth, in feet, Material below land surface Pamlico Sand Sand, gray, quartz _......_-- ..- _______ 0- 3 Fort Thompson Formation Shell bed, marine ... ___------......--_ .._-- .._____ 3- 7 Sand, light-gray, marly ---.... --_. ---.__- __ 7- 18 Caloosahatchee Marl Marl, dark-gray, very sandy, somewhat shelly 18- 30 Shell bed, dark-gray, sandy (shell marl) ._-------------- 30- 44 Tamiami Formation Shell marl, light-gray, sandy --..-..-...-- _..._-- 44- 54 Marl, light-green, clayey, sandy _--..--_-_.._ .--- 54- 75 WELL 28 NW%/SE% sec. 11, T. 42 S., R. 32 E. Depth, in feet, Material below land surface Recent soils Peat __--__ --___----_____ 0 3 Pamlico Sand Sand, gray, quartz -_- _--_ ___-__ 3- 10 Caloosahatchee Marl Shell bed containing quartz sand and the following mol- lusks: ___ 10- 14 Pseudomiltha anodonta (Say) Transennella caloosana Dall Chione cancellata (Linnaeus) Anomalocardia caloosana (Dall) Turritella sp. Nassarius vibex (Say) FLORIDA GEOLOGICAL SURVEY Olivella mutica (Say) Marginella sp. Sand, gray, quartz, and shells containing the following: 14- 17 Phaeoides pensylvanicus (Linnaeus) Laevicardium serratum (Linnaeus) Transenella caloosana Dall Chione cancellata (Linnaeus) Anomalocardia caloosana (Dall) Tellina (Merisca) dinomera Dall Corbula caloosae Dall Fissuridea carditella Dall Cerithium sp. cf. C. glaphyrea litharium Dall Turritella perattenuata Heilprin Nassarius sp. ind. Marginella gravida Dall? Olivella mutica (Say) Terebra dislocata Say Sand, white, quartz ___ __--___ --- 17- 55 Tamiami Formation Sand, gray, coarse, quartz, shelly .... ..----.------... 55- 63 WELL 29 SW4 SWU sec. 22, T. 40 S., R. 32 E. Depth, in feet, Material below land surface Recent sand and soils Sand, quartz __ ----- -- ------ 0- 4 Muck, peat, black 4____-.. -----_------~--- -.. ..-- 4- 8 Fort Thompson Formation Sand, gray, quartz, marly ___8 .......--..-------.. 8- 11 Caloosahatchee Marl Marl, gray, sandy, with a few shells ... -- ---------------- 11 15 Marl, gray -___-__-__ ---------------------- 15- 20 Marl, gray, sandy, very shelly ____......... .....--------- 20- 27 Marl, gray, sandy, slightly shelly -----___- ... .--- --- 27- 34 Tamiami Formation Shell marl, light-gray, very sandy _...------------- 34- 38 Shell marl, light-gray, sandy 38- 42 Sand, light-gray, quartz, slightly shelly --_-__._-- 42- 48 Marl, grayish-green, sandy, shelly -___- .... 48- 56 Marl, greenish-gray, silty, plastic _.___-_-___-- 56 62 Marl, gray, sandy, very shelly 62 75 |
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| MILLISECOND | CLASS.METHOD | MESSAGE |
|---|---|---|
| 0 | sobekcm_page_globals.constructor | |
| 0 | sobekcm_page_globals.constructor | Application State validated or built |
| 0 | sobekcm_database.verify_item_lookup_object | |
| 0 | sobekcm_page_globals.constructor | Navigation Object created from URI query string |
| 0 | sobekcm_database.verify_item_lookup_object | |
| 0 | sobekcm_page_globals.display_item | Retrieving item or group information |
| 0 | sobekcm_page_globals.get_entire_collection_hierarchy | Retrieving hierarchy information |
| 0 | sobekcm_assistant.get_entire_collection_hierarchy | |
| 0 | cached_data_manager.retrieve_item_aggregation | |
| 0 | cached_data_manager.retrieve_item_aggregation | Found item aggregation on local cache |
| 0 | item_aggregation_builder.get_item_aggregation | Found 'all' item aggregation in cache |
| 0 | system.web.ui.page.page_load (ufdc.page_load) | |
| 0 | sobekcm_page_globals.constructor.on_page_load | |
| 0 | html_echo_mainwriter.add_style_references | Adding style references to HTML |
| 0 | html_echo_mainwriter.add_text_to_page | Reading the text from the file and echoing back to the output stream |
| 71 | html_echo_mainwriter.add_text_to_page | Finished reading and writing the file |
