Citation
Water resources of Broward County, Florida ( FGS: Report of investigations 65 )

Material Information

Title:
Water resources of Broward County, Florida ( FGS: Report of investigations 65 )
Series Title:
( FGS: Report of investigations 65 )
Creator:
Sherwood, C. B
McCoy, H. J ( Henry Jack )
Galliher, C. F. ( joint author )
Geological Survey (U.S.)
Place of Publication:
Tallahassee
Publisher:
State of Florida, Dept. of Natural Resources, Division of Interior Resources, Bureau of Geology
Publication Date:
Language:
English
Physical Description:
iv, 141 p. : ill. ; 23 cm.

Subjects

Subjects / Keywords:
Hydrology -- Florida -- Broward Co ( lcsh )
Broward County ( local )
City of Pompano Beach ( local )
City of Fort Lauderdale ( local )
City of Tallahassee ( local )
Lake Okeechobee ( local )
City of Boca Raton ( local )
Canals ( jstor )
Aquifers ( jstor )
Rain ( jstor )
Rivers ( jstor )
Quartz ( jstor )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Bibliography: p. 139-141.
Statement of Responsibility:
by C. B. Sherwood, H. J. McCoy, C. F. Galliher ; prepared by the United States Geological Survey, in cooperation with the Bureau of Geology, Florida Department of Natural Resources and Broward County.

Record Information

Source Institution:
University of Florida
Rights Management:
The author dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law and all related or neighboring legal rights he or she had in the work, to the extent allowable by law.
Resource Identifier:
022461305 ( aleph )
01274440 ( oclc )
AES0068 ( notis )
75620613 //r862 ( lccn )

Full Text





STATE OF FLORIDA DEPARTMENT OF NATURAL RESOURCES
Randolph Hodges, Executive Director





DIVISION OF INTERIOR RESOURCES Robert 0. Vernon, Director




BUREAU OF GEOLOGY C. W. Hendry, Jr., Chief







Report of Investigation No. 65


WATER RESOURCES OF BROWARD COUNTY, FLORIDA







By
C. B. Sherwood, H. J. McCoy, and C. F. Galliher



Prepared by the UNITED STATES GEOLOGICAL SURVEY in Cooperation with the BUREAU OF GEOLOGY
FLORIDA DEPARTMENT OF NATURAL RESOURCES and
BROWARD COUNTY


TALLAHASSEE 1973






DEPARTMENT
OF
NATURAL RESOURCES


REUBIN O'D. ASKEW Governor


RICHARD (DICK) STONE
Secretary of State




THOMAS D. O'MALLEY
Treasurer




FLOYD T. CHRISTIAN Commissioner of Education


I


ROBERT L. SHEVIN
Attorney General




FRED 0. DICKINSON, JR.
Comptroller




DOYLE CONNER
Commissioner of Agriculture


W. RANDOLPH HODGES
Executive Director



'SCIENCE LIBRARtYi








ii







LETTER OF TRANSMITTAL


BUREAU OF GEOLOGY
Tallahassee
August 24, 1973


Honorable Reubin O'D. Askew, Chairman Department of Natural Resourices Tallahassee, Florida

Dear Governor Askew:

The Bureau of Geology is publishing as Report of Investigations No. 65, a report on the "Water Resources of Broward County, Florida". This report was prepared by C. B. Sherwood, H. J. McCoy, and C. F. Galliher as a part of the cooperative program between the U. S. Geological Survey and the Bureau of Geology.

The explosive urbanization of Broward County has been accompanied by numerous natural and man-made water problems. Natural problems of flood and drought are caused by extreme variations in rainfall, while man-made problems include sea-water intrusion resulting from over drainage, obtaining adequate water supplies for a mushrooming population, and pollution caused by disposal of wastes.

The demand for fresh water in Broward County is constantly increasing and will probably double within the next fifteen years. A complete understanding of the water resources potential is of utmost importance to the management of the resources.

Respectfully yours,



Charles W. Hendry, Jr., Chief Bureau of Geology




















































Completed manuscript received July 26, 1973 Printed for the Florida Department of Natural Resources
Division of Interior Resources
Bureau of Geology
by Ambrose the Printer
Jacksonville, Florida Tallahassee 1973

iv








CONTENTS


Abstract ............
Introduction ..........
Purpose and scope . .
Previous investigations .
Acknowledgments . .
General features .... Hydrologic setting ......
Climate ...........
Topography and drainage Geology ...........
Surface-flow system ....
Water management . .
History ......


Water-conservation areas and pump stations . .
Hydrologic characteristics of primary canals and
water-conservation areas .................
Hillsboro Canal ....................
Pompano Canal (C-14) and Cypress Creek Canal
Middle River Canal (C-13) ..............
North New River-Plantation Canals .......
South New River Canal (C-11) .........
Snake Creek Canal (C-9) ................
Effects of water management ...............
Intracoastal Waterway ...............
Ground water .....................
Biscayne aquifer ..................
Recharge and discharge ...............
Water-level fluctuations ...............
Well development ...................
Hydraulic properties ..................
Floridan aquifer ..................
Water quality *. .......................
Natural constituents ................
Ground water .....................
Surface water .....................
Contamination of water resources .........
Sea-water intrusion .................
Contamination related to man's activities .
Water use ...........................
Public water supplies ..................
Fort Lauderdale ...................
Hollywood ...................
Pompano Beach ...................
Irrigation use .......................
Industrial use .......................
Future water supplies ...................
Summary ...........................
Well numbers ........................
Well logs ...........................


References ........................ ......... ........... 139


Page
1 3
4 4 5
5 8 8 8
12 12 13 13
14


16
16 19 22 22 24 27
28 39
44 46 48 49 65 66
68 68 69 69
75 76 82
90 110 ill
114 115 115 118
120 121 123 129
130







ILLUSTRATIONS

Figure Page 1. Peninsular Florida showing location of Broward County ... ............ 6

2. Population growth of Broward County and State of Florida 1925 projected to 1985 (Statistical abstract, Broward County, 1965) .... .............7

3. Distribution of rainfall by months and the annual rainfall, 1943 68, at the North New River Canal at the Broward Palm Beach County line ........... 9

4. Exceedance probability curve for rainfall at the North New River Canal at the Broward Palm Beach County line, 1943 68 ....................... 10

5. Southeastern part of the Central and Southern Florida Flood Control District. 11

6. FCD S-7 (Pump Station) on North New River Canal at the Palm Beach Broward County line ....... .............................. 15

7. Periods of record at selected surface-water data-collection stations in Broward County ......... ................................... 17

8. Location of surface-water daily data-collection stations in Broward County . 18

9. Monthly mean discharge and monthly extremes in stage in the Hillsboro Canal at Deerfield Beach (2815) and S-39 (2813), average monthly rainfall at Belle Glade and Pompano Beach, and a record of gate operations for the periods of
record ......... ...................................... 20


10. Monthly mean discharge and monthly extremes in stage in the Pompano Canal
at Pompano Beach (2820) and at S-38 (2817) and in Cypress Creek Canal at
S-37A (2821) with a record of gate operation for the periods of record . . 21

11. Monthly mean discharge and monthly extremes in stage in the Middle River
Canal at S-36 (2827) and a record of gate operations, 1963 70 ........ ... 23

12. Monthly mean discharge and monthly extremes in stage in the North New River Canal at Sewell Lock (2850) and S-34 (2847), the average monthly rainfall at Fort Lauderdale, Belle Glade and Dania, and a record of gate
operations for the periods of record ...... ...................... 25


13. Monthly mean discharge and monthly extremes in stage in Plantation Canal at S-33 (2832) and a record of control operations, 1963 70 ........ ...... 26

14. Monthly mean discharge and monthly extremes in stage for South New River Canal at pumping stations S-9 (2854) and S-13 (2861) with a record of gate
operations, 1963 70 ...................................... 28


15. Monthly mean discharge in Snake Creek Canal at S-30 (2861.8), 67 Avenue (2862) and S-29 (2863), monthly extremes in stage above S-29 and S-30, and
a record of control operations for the periods of record ................ 29






ILLUSTRATIONS continued

Figure Page 16. Cumulative runoff-year discharge to the ocean from the Hillsboro and North
New River Canals plotted against cumulative mean annual rainfall (above 37 inches/year) at Belle Glade, Fort Lauderdale, Dania and Pompano Beach (after
Leach and others, 1970) ....... ............................ 31

17. Flow-duration curves for Hillsboro and North New River Canals, 1941 53
and 1962- 68 ........ ................................. 32

18. Flow-duration curves for selected canals in Broward County, 1962 68 . . 33 19. Low-flow frequency curves for the Hillsboro Canal, 1941 53 and 1962 68 35 20. Low-flow frequency curves for the North New River Canal, 1941 53 and
1962-68 ...... .................... ............ ... 36

21. Location of recording tide gages in the Intracoastal Waterway ............ 38

22. Typical tidal fluctuations at selected sites in the Intracoastal Waterway, May
5-14, 1968 (Schneider, 1970, fig. 2) ........................... ..41

23. Seasonal changes of the monthly mean high and low-tide and half tide at
selected sites in the Intracoastal Waterway (after Schneider, 1970, figs. 3 and 4) 42 24. Effects of strong easterly winds Oct. 29-31, 1969 on tide patterns at selected
sites in the Intracoastal Waterway (Schneider, 1970, fig. 5) ............. 43

25. Yearly mean water levels at Miami Beach, Florida, showing the average rise in
sea level (Schneider, 1970, fig. 6) ...... ....................... 44

26. Lithologic logs along line A-A' in figure 29 ...... .................. 45

27. Lithologic logs along line B-B' in figure 29 ........................ 46

28. Lithologic logs along line C-C' in figure 29 ........................ 47

29. Location of test holes and lines of lithologic logs in eastern Broward County 48 30. Diagrammatic portrayal of recharge to and discharge from the Biscayne
aquifer in Broward County ....... .......................... 50

31. Water-level observation stations on wells and canals in Broward County . .. 51 32. Hydrographs of wells in the coastal intercanal areas of Broward County . 53 33. Hydrographs of wells in the interior intercanal areas of Broward County . 54 34. Hydrographs of wells in major well-field areas of Broward County ... ...... 55

35. Water-level contour map of eastern Broward County under record low conditions, May 5, 1971 ....... ............................ 56






ILLUSTRATIONS continued


Figure Page 36. Water-level contour map of eastern Broward County under record high
conditions, Nov. 1, 1965 ...... ........................... 57

37. Water-level contour map of eastern Broward County under near-average
conditions, May 25-26, 1964 ....... ......................... 58

3& Hydrographs of wells in the Pompano Beach well field and the Fort
Lauderdale Dixie and Prospect well fields, 1965 and 1971 ... .......... 59

39. Water-level contour map of the Pompano Beach well field and surrounding
area during a period of low-water levels and peak pumpage, May 5, 1971 . 60 40. Water-level contour map of the Fort Lauderdale Prospect well field and
surrounding area during a period of low-water levels and peak pumpage, May
5, 1971 ......... .................................... 61

41. Water-level contour map of the Fort Lauderdale Dixie well field and
surrounding area during a period of low-water levels and peak pumpage, May
5, 1971 ......... .................................... 62

42. Water-level contour map of eastern Broward County, October 19, 1971 . .. 64 43- Location of water sampling stations shown in tables 3 and 4 ... ......... 70

44. Variation in dissolved solids, hardness and iron in ground water of eastern
Broward County, 1964 (adapted from Grantham and Sherwood, 1968) . .. 74 45. Extent of sea-water intrusion 1970 ...... ...................... 83
46. Chloride content of water at salinity control structures during periods of high
and low flow ........ .................................. 84

47. Discharge and chloride content of water from tidal reaches of selected canals
(see figure 43 for locations) ....... .......................... 85
48. Effects of controlled and uncontrolled coastal canals on sea-water intrusion 87 49. Water-level contour maps of the Prospect well field area Aug. 6, 1956 and
March 23, 1961 determined by analog plotter and model and by field measurer
ment ......... ...................................... 88

50. Salinity control measures in the Middle River Canal Prospect well field area 89 5I. Location of sewage treatment plants and points of disposal of effluents . .. 92 52. Location of surface-water sampling sites and traverse lines for monitoring
levels of contaminants in Broward County ........................ 95

53. Sources and biological magnification of DDT+DDD+DDE residues in aquatic
communities in and near Everglades National Park (Kolipinski and Higer,
1969, fig. 20) ........ ....... .......................... 96








ILLUSTRATIONS continued


Figure Page 54. North New River Plantation Canal system showing location of water
sampling stations and field analyses made during traverses, March 5 6 and
June 25, 1969 ........ ................................. 105

55. Pompano Cypress Creek Canal system showing location of water sampling
stations and field analyses made during traverses, March 7 and June 24, 1969 106 56. Analyses of diurnal samples for dissolved oxygen content in the North New
River Plantation Canal system, March 18 19 and July 23, 24, 1969 ..... ..107 57. Analyses of diurnal samples for dissolved oxygen content in the
Pompano-Cypress Creek Canal system, March 20 21 and July 23 24, 1969 109 58. Location of major water treatment plants and well fields in Broward County 110 59. Monthly pumpage from the Fort Lauderdale Dixie and Prospect well fields
and rainfall at Fort Lauderdale 1952 69 ..... ................... 114

60. Monthly pumpage from the Hollywood well field 1948 69 ............. 116

61. Monthly pumpage from the Pompano Beach well field and rainfall at Pompano
Beach 1954 69 ....... ................................ 117

62. Photographs of golf course and truck farm irrigation systems in north Broward
County ........ ..................................... 119

63. Public water use in Broward County, 1945 85 ..... ................ 121

64. Annual discharge to the sea from primary canals in Broward County, 1964 . 123









TABLES

Table Page 1. Average monthly rainfall at Fort Lauderdale and Boca Raton ............ 10

2. Mean values of high and low water, tidal range, half tide and time difference observed in the Intracoastal Waterway Mar. 1, 1968 through Feb. 28, 1969
(Schneider, 1970, table 1) ....... ........................... 40

3. Chemical analyses of ground water in Broward County (adapted from Grantham and Sherwood, 1968) ...... ........................ 71

4. Selected chemical analyses of surface water in Broward County (extremes in chemical content) ........ ............................... 77

5. Treatment facilities at major sewage treatment plants in Broward County and points of disposal of effluents ....... ......................... 93
6. Results of sampling for man-made contaminants in Broward Canals 1969 A. Chemical and biological analyses ..... ..................... 97

B. Pesticide Analyses ....... ........................... 99

7. Major water treatment plants in Broward County .... ............... 112







WATER RESOURCES OF BROWARD COUNTY, FLORIDA


By
C. B. Sherwood, H. J. McCoy, and C. F. Galliher


ABSTRACT

Broward County has large potential supplies of fresh water because of its almost 60-inch annual rainfall and its massive man-made surface-water management system integrated with the highly permeable Biscayne aquifer. However, the rapid urbanization of the area has been. accompanied by major natural and man-made water problems, most of which intensify with mushrooming population. Natural problems of flood and drought are caused by extreme variations in rainfall that range from as much as 20 inches per day during the rainy season to little or none for extended periods in the dry season. Man-made problems include contamination by sea-water intrusion or by man-made wastes and management of water resources so that maximum long-term supplies can be developed. Although the development of adequate supplies for all needs will become a more critical problem in the future, contamination is the chief threat to present supplies.

Surface water is derived from rainfall, ground-water inflow, and releases and seepage from interior water conservation areas. The quality of the surface waters is initially good but variable; mineral content generally does not exceed 500 mg/l (milligrams per liter).

Although the surface-water supply is large it is variable because of the seasonal nat.ure of the rainfall. Also losses from the system are high: of the 60 inches of annual rainfall, an average of 42 inches is lost by evapotranspiration, and during 1963-68, 1,300 cfs (cubic feet per second), about 840 mgd (million gallons per day), was lost by seaward flow from the eight primary canals. However, since the late 1950's, water management has greatly reduced the seaward flow. The average annual flow from the Hillsboro and North New River Canals reduced by approximately 260 cfs and 375 cfs, respectively.

The unconfined Biscayne aquifer is the source of all fresh ground water in Broward County. The aquifer is composed chiefly of limestone, sandstone, and sand which range in age from late Miocene through the Pleistocene. The aquifer extends from the surface to a depth of about 200 feet along the coast, thins westward to a depth of about 70 feet in central Broward County and pinches out near the west county line. Wells that tap the thick limestone in the deep part (100 or more feet) of the aquifer near the coast yield more than 1,000 gpm (gallons per minute). The transmissivity of the aquifer ranges from 0.4 mgd per







2 BUREAU OF GEOLOGY

foot in the northern part of the county to 2.5 mgd per foot near the southern part. The quality of the ground water is generally within the standards for potable water. It is a hard, calcium bicarbonate type, and in the southeastern part of the county it contains iron in objectionable concentrations.

Aquifer replenishment is by local rainfall and seepage from controlled canals and from the water conservation areas. Losses are by evapotranspiration, by ground-water flow to canals and the sea and by pumping from wells. Of the 60 inches of annual rainfall approximately 17 inches enters the aquifer, of which less than 2.5 inches is withdrawn 'by water users, and about 14.5 inches is discharged to the sea 13.5 inches through the canals and about 1 inch by ground-water outflow along the coast. During extended dry periods when withdrawals are greatest recharge is only available from the canals.

The confined Floridan aquifer extends from a depth of about 900 feet to more than 3,000 feet and is overlain by a 500-to 600-foot section of clay, silt and marl of low permeability. Although water in wells tapping the Floridan aquifer will rise almost 40 feet above msl (mean sea level) and flow as much as 2,000 gpm, the water is not potable. Nevertheless, the water quality is adequate for such purposes as cooling or desalination and the aquifer has potential for storing fresh water or for effluent disposal.

The greatest inland penetration of sea water into the Biscayne aquifer is in the vicinity of the greatest concentration of tidal canals. This intrusion can be effectively controlled by the construction of salinity control structures in the canals and maintaining adequate fresh-water levels upstream.

Man-made contamination has occurred in both ground and surface waters. Surface-water contarpination appears more serious because of the introduction of large quantities of effluent waste into the waterways. Although evidence of man-made contaminants was detected in all canals, levels of nutrients, BOD (biochemical oxygen demand), and pesticides were highest and levels of dissolved oxygen were lowest in the North Fork New River-Plantation Canal (C-I 2) system which receives large quantities of treated sewage effluent and has a relatively low flow. Coliform bacteria in most canals sampled during June 1968 were above the criterion of the Florida Pollution Control Department for recreational waters (2,400 coliform colonies per 100 milliliters). The dissolved oxygen content ranged from 0.2 to 8.2 mg/l. Generally, relatively low levels of dissolved oxygen are common throughout the Broward canal system. More than half the 45 area-wide samples contained less than 4 mg/l, and nine samples less than 2 mg/l. Levels of pesticides detected in water in the canal network are extremely low; however, pesticides are concentrated manyfold in the bottom sediments.







REPORT OF INVESTIGATIONS NO. 65


Water use in Broward County is increasing at a faster rate than population, and complete urbanization will ultimately require the development of the maximum possible water supplies. More than 32 municipal and privately owned water utilities furnish about 32 billion gallons of water per year (88 mgd on the average) for a permanent population of 500,000, a peak tourist season population of 890,000, and most commercial use in the county. The largest utility, Ft. Lauderdale's, furnishes a peak supply of more than 60 mgd to a maximum population of 160,000. Urban water use is greatest, about 150 mgd, during the winter tourist season Which coincides with the dry season when domestic and recreational use is maximum and lawn irrigation is heavy. Irrigation use is little noted because of the booming urban activity. However the total irrigation use is high, almost equal to the 32 billion gallons per year urban use. Most of the industrial water used, more than 1.5 bgd (billion gallons per day) is salty water for cooling at the two power plants; fresh-water industrial use is estimated to be 35 mgd. Public water needs by 1985 may be as much as 80 billion gallons per year, an average of about 220 mgd. Current data (1971) indicate that peak day needs are commonly as much as twice the average daily demand. If use by agriculture and industry increases in proportion to public use it would amount to 330 mgd in 1985 and total water use would average about 550 mgd.

INTRODUCTION

The explosive urbanization of Broward County has been accompanied by numerous natural and man-made water problems. Natural problems of flood and drought are caused by extreme variations in rainfall that may range from as much as 20 inches per day during hurricanes in the rainy season, to little or none during many months in the dry season. Man-made water problems include: sea-water intrusion that resulted from overdrainage of the area; obtaining adequate water supplies for the mushrooming population; and pollution caused by the disposal of increasing quantities of wastes.

The threat of sea-water intrusion into municipal well fields is a historic problem. As large amounts of fresh water were removed by drainage for ubanization, regional fresh-water levels declined and sea water advanced up the canals and moved inland through the aquifer during dry periods. This insidious invasion of salt water is an ever-present danger to the fresh-water supply of well fields near the coast.

The demand for water in Broward County is constantly increasing, owing to the rapid growth in population. State and County planners indicate this growth is destined to continue, and if projections are reasonably accurate, the demand for fresh water will more than double within the next 15 years.






BUREAU OF GEOLOGY


Waste treatment and disposal have become major problems in Broward County. Most of the water used for domestic purposes is discharged through septic tanks or directly into canals, streams and the ocean from sewage treatment plants. As water use increases, the magnitude of the problems will increase also. The method and degree of treatment, and the locations of disposal sites will strongly affect the quality and quantity of water available for future supplies.

PURPOSE AND SCOPE

The purpose of this report is to describe the water resources and water problems of Broward County and to evaluate the present and future potential of the resources. The water resources are portrayed by description of ground-and surface-water flow systems; hydrologic characteristics of the principal aquifers, primary canals, and water conservation areas; and a summary of water-quality and water-use data.

The report was prepared by the U. S. Geological Survey in cooperation with Broward County as part of the State-wide program with the Bureau of Geology, Division of Interior Resources, Florida Department of Natural Resources. This is the fourth report resulting from the continuing investigation of the water resources of Broward County.

PREVIOUS INVESTIGATIONS

Numerous studies have been made on selective topics related to the water resources of Broward County. A report by Collins and Howard (1928) contains a few chemical analyses of water in Broward County. Parker and others (1955) presented data on the occurrence, movement and the quality of ground water and surface water in Broward County as well as informtion on salt-water intrusion. Vorhis (1948) studied the geology and ground-water resources of the Ft. Lauderdale area. Schroeder, Klein, and Hoy (1958) made a study of the hydrology of the Biscayne aquifer in which they delineated the approximate areas of salt-water intrusion in Broward County. A more detailed investigation of salt-water intrusion and some work on water quality in the Oakland Park area was done by Sherwood (1959). The hydrology of the Biscayne aquifer in the Pompano Beach area was studied by Tarver (1964).

Several recent reports have resulted from the current investigation of the water resources of Broward County. Sherwood and Grantham (1965) investigated the mechanics of salt-water intrusion and the effects of salinity control measures in Broward County. A report on the chemical quality of waters of Broward County, by Grantham and Sherwood (1968), included data on








REPORT OF INVESTIGATIONS NO. 65


pollution from man-made effluents, as well as salt-water intrusion and natural constituents in fresh-water supplies. The reaction of the ground-and surface-water flow system to extreme hydrologic conditions was reported by McCoy and Sherwood (1969). McCoy and Hardee (1969) studied the geology and salt-water intrusion of the Deerfield Beach area as part of the ground-water resources study of the lower Hillsboro Canal area in northern Broward and southern Palm Beach County. Schneider (1970) reported on tidal relations along the Intracoastal Waterway.


ACKNOWLEDGMENTS

The authors are grateful to many individuals and agencies for much of the technical data included in this report. Special thanks are extended to Mr. J. Stanley Weedon, Director, Broward County Water Resources Department, for his cooperation, courtesy, and assistance. Messrs. H. J. Voegtle and J. Hardee, U. S. Geological Survey, were responsible for the collection of much of the physical and chemical data throughout the investigation. Appreciation is expressed also to the municipal water-supply officials for their cooperation in the use of their facilities and their wholehearted support during the investigation. Considerable data on sea water intrusion and the development of ground-water supplies were collected in cooperation with the cities of Fort Lauderdale and Pompano Beach. Accurate monitoring of flows in the highly controlled canal system has been greatly aided by the excellent cooperation of personnel of the FCD (Central and Southern Florida Flood Control District). The collection of data on contaminants in water resources was begun in 1969 in cooperation with the Broward County Air and Water Pollution Control Board. Water quality data in canals adjacent to the water conservation areas was collected in cooperation with the FCD. The collection of water-quality data was expedited by assistance from personnel of the Broward County Health Department.

GENERAL FEATURES

Broward County borders the Atlantic ocean in southeastern Florida, southeast of Lake Okeechobee (fig. 1). It is rectangular in shape and has an area of 1,220 square miles. The western two-thirds of the county lies within the water conservation areas of the FCD (Central and Southern Florida Flood Control District).

The county lies in the center of one of the fastest growing urban areas of Florida and the United States. This metropolitan area extends over Palm Beach, Broward and Dade Counties with the bulk of the population concentrated along the seacoast and coastal ridge. Because of the desirability of the coastal land and







BUREAU OF GEOLOGY


Figure 1. Peninsular Florida showing location of Broward County.


the limitations to westward expansion because of the conservation areas, this narrow strip of land from Palm Beach to Homestead is rapidly becoming a megalopolis which will eventually encompass the entire southeastern coast of the State. From 1950 to 1970, the tri-county population increased from 693,705 to 2,236,645 (U. S. Census Bureau, 1970). Neither of these figures includes the winter residents and vacationists, whose influx in the winter months often doubles the population. During the same period the population of Broward County grew from 83,933 to 620,100. In 1925, the population of Broward County was about 14,000; that of Florida about 1 million; by 1985 the projected populations will be 1.2 and 14 million respectively (fig. 2).








REPORT OF INVESTIGATIONS NO. 65


10
1925


1935 1945 1955 1965 1975 1985


Figure 2. Population growth of Broward County and State of Florida
192S projected to 198S (Statistical abstract, Broward County,
1965).







BUREAU OF GEOLOGY


HYDROLOGIC SETTING

CLIMATE

The climate of Broward County is semi-tropical marine, characterized by warm humid summers and mild dry winters. Mean annual temperature is 73 0 F, with infrequent extremes of temperature ranging from 29 0 F to 96 0 F (U. S. Department of Commerce, 1968). The climate is tempered by prevailing southeast winds, which bring warm moist air from the ocean, and by the Gulf Stream which passes within a few miles of the shoreline. January is usually the coldest month, averaging about 680 F and August is usually the hottest, averaging 83 0 F.

The average annual rainfall in the county ranges from about 52 inches in the western sector to as much as 60 inches along the coast. Wide differences in yearly totals have been recorded; in some years the rainfall is only 30 inches, in others, more than 100.

Rainfall is unevenly distributed throughout the year; about 75 percent of the rain falls in June October. January is usually the driest month with an average rainfall of about 2 inches; September is usually the wettest month with an average rainfall of about 8.5 inches. For example, the average monthly rainfall at Fort Lauderdale and Boca Raton in January is 2.20 and 2.62 inches; in September, 8.98 and 8.16 inches (table 1). Rainfall is often unevenly distributed geographically. For example, on October 14-15, 1965, 25 inches of rain fell at a coastal yacht basin in-Fort Lauderdale and less than 5 inches fell at an agriculture station 8 miles inland.

Annual rainfall at North New River Canal at Palm Beach Broward County line (pumping station S-7) during a 26-year period averaged 52.10 inches; was 76.47 inches in 1947 and 30.40 inches in 1949 (fig. 3). Rainfall during that time was above average 57 percent of the time, and exceeded 70 inches 10 percent of the time (fig. 4).

TOPOGRAPHY AND DRAINAGE

The land surface slopes almost imperceptibly to the southeast. Land surface ranges from about 13 feet above msl (mean sea level) in the northwestern part of the county to less than 5 feet in the southern part. Most of the land is 5 to 10 feet high; some is higher along the coastal ridge which parallels the seacoast 2 to 3 miles inland. The coastal ridge is about 22 feet above msl in the Pompano Beach Deerfield Beach area. West of the coastal ridge, the Everglades extends some 40 miles inland and covers the western two-thirds of the county.









REPORT OF INVESTIGATIONS NO. 65


DISTRIBUTION OF RAINFALL BY MONTHS


t I I I I I I I I I I I I I I I III I I I I I I I MEAN MIE


Figure 3. Distribution of rainfall by months and the annual rainfall,
1943-68, at the North New River Canal at the Broward Palm
Beach County line.


80
(n

60

-40
z 4 21


luin







10 BUREAU OF GEOLOGY
Table 1. Average monthly rainfall at Fort Lauderdale and Boca Raton, Florida1 Month Fort Lauderdale Boca Raton


January February March April May June July
August September October November December
Yearly Average


2.20 2.06
2.84 4.19 5.29
7.42 5.96 6.88 8.98 8.39 3.18 2.90 60.29


2.62
3.04 3.08 2.37
4.50 8.00 5.57
6.35 8.16 7.29
-2.65
2.40
56.03


_ Record from U.S. Weather Bureau, Reports of Climatological Data. Complete record at
Fort Lauderdale for period 1913-1968. Incomplete records at Boca Raton for period
1954-1968


94 7(


0- I I I I I

2


0


0



1943-68 YEAR AVERAGE
0


0

0


0






o 10 20 30 )4o so 60 70 80 90 PERCENTAGE OF YEARS RAINFALL EQUALED OR EXCEEDED THAT SHOWN


Figure 4. Exceedance probability curve for rainfall at the North New River
Canal at the Broward Palm Beach County line, 1943-68.


00


4


3


2







REPORT OF 'INVESTIGATIONS NO. 65


HENDRY COUNTY


Figure 5. Southeastern part of the Central and Southern Florida Flood
Control District (FCD).






BUREAU OF GEOLOGY


The present day drainage is largely controlled by the system of canals of the FCD (fig. 5), the Broward Water Resources Department, and the various local drainage districts. In 1953, with the completion of the FCD levee barrier along the east border of the Everglades, the county was divided into two distinctly different land use areas; a 410-square-mile area east of the levee, suitable for urban use and agriculture, and an area of 810 square miles west of' the levee, suitable only for water conservation, recreation, and as a wildlife refuge.

The primary canals of the FCD are, generally, controlled improvements to natural drainageways that have been extended to Lake Okeechobee. Secondary canals affect smaller areas between primary canals and the direction of drainage in these areas is dependent on local topography and water control.


GEOLOGY

The most common materials in Broward County to a depth of approximately 300-400 feet are sand and limestone, which range in age from Pleistocene to late Miocene. This 300-to 400-foot section is called the Biscayne aquifer and it contains all the fresh-water-bearing materials in Broward County. The Biscayne aquifer is discussed in detail in the section on ground water (p. 85). Underlying the Biscayne aquifer is a 500-600 foot section of marl and clay of Miocene age. Below this bed is the Floridan aquifer. This aquifer, composed chiefly of limestones, dolomites, and evaporites which range in age from early Miocene to early Eocene, extends to depths of more than 3,500 feet, and contains highly mineralized water. Similar materials which are not generally considered part of the Floridan aquifer extend to depths of more than 15,000 feet.


SURFACE-FLOW SYSTEM

In Broward County large quantities of surface water flow seaward in a system of controlled canals or are stored in the FCD conservation areas. Flow to the ocean from eight primary canals (fig.l), for 1963-1968, averaged more than 1,300 cfs (cubic feet per second), or more than 306 billion gallons per year.

The supply is variable because of the seasonal nature and annual variability of rainfall (fig. 3). In addition, losses from the system are very high. Evapotranspiration losses account for as much as two-thirds of the annual








REPORT OF INVESTIGATIONS NO. 65


rainfall. Although little surface water is used directly, except for irrigation, large quantities replenish the aquifer in coastal areas during the long dry periods.

WATER MANAGEMENT

HISTORY

Maps of the 1850's show the Broward County area as a vast swampy wilderness, virtually uninhabited except for a narrow strip along the coast. This coastal ridge acted as a natural barrier to the seaward flow of water from the Everglades. Drainage of the eastern part of the Everglades was started as early as the 1850's. However, drainage was not effective until 1906, when the EDD (Everglades Drainage District) began a dredging program. Between 1906 and 1927, under the direction of EDD,440 miles of canals were dug, 47 miles of levees were constructed, and 16 dams and locks were installed.


When the EDD project was completed in 1928, four of the major drainage canals connecting Lake Okeechobee to the ocean and numerous secondary canals formed the framework of the present drainage system for Broward County. Th four major canals included the Hillsboro, Miami, and the North and South New River Canals, and the secondary canals included Pompano, Middle River, Plantation, and Snake Creek Canals. This network of canals did much to open up new land in the eastern part of the county, but it was apparent that natural flow was inadequate to prevent flooding from rainstorms of high intensity.


Because of this inadequacy and more directly because of the public reaction to the flood of 1947, the Florida Legislature created the FCD in 1948 as a public corporation with jurisdictional control over the surface-water resources of the 17 counties comprising the district. In addition to the primary objectives of flood control and water conservation, the project was designed to prevent overdrainage, permit additional urban and agricultural development, prevent salt-water intrusion, provide ground-water recharge, and improve fish and wildlife conservation. The FCD has been in the process of attaining these objectives since it was formed and although still incomplete, their effects have been noted in all of the 17 counties.


A major project was the construction of a levee from Lake Okeechobee to South Dade County to divert interior flood waters away from the coastal areas and prevent a recurrence of conditions which existed during the 1947 flood.








BUREAU OF GEOLOGY


The next major project was the creation of the Water Conservation Areas to store the diverted water and provide a reserve supply for the dry months because southeastern Florida was lacking in natural water-storage basins.

WATER-CONSERVATION AREAS AND PUMP STATIONS

Water-conservation areas cover parts of Palm Beach, Broward, and Dade Counties, and have a total area of 1,340 square miles, 787 square miles of which are in Broward County (fig. 5). To provide better water control, the areas are divided into five interconnected pools, each enclosed by levees 10 to 15 feet high. The pools are designated by number from north to south as Water-Conservation Areas 1, 2A, 2B, 3A, and 3B (fig. 5). All except area 1 lie wholly or partly within Broward County. Under FCD staging, flow will gravitate from Water-Conservation Area 1 to 2A, from 2A to 2B and 3A, and from 3A to 3B. Flow interchange between all areas is regulated by gated controls or stoplog spillways. The regulation schedules in the conservation areas vary during the year as levels are lowered before the hurricane season. Levels scheduled for conservation areas 1, 2 and 3 are 15-17 feet, 13-14.5 and 9.5-10.5 feet above msl respectively, and corresponding storage capacities are 59,500-293,000 acre-feet, 2701,000-366,000 acre-feet, and 560,000-1,015,000 acre-feet, respectively.

Major components of the FCD system are 17 pump stations planned or completed in the system. Four of these, S-7, S-8, S-9, and S-13 (fig. 5) are now operating in Broward County.

S-7 is on the North New River Canal at the Palm Beach Broward County line, in the westernmost corner of Water-Conservation Area 2A. It is equipped with an electrically operated sluice gate and three 895 hp diesel powered pumps capable of pumping 2,490 cfs or 1,609 mgd (see photograph, fig. 6). S-7 is designed to remove three-fourths of an inch of runnoff per day from a 125-square-mile area north of the county line and discharge it into Water-Conservation Area 2A.

S-8 is on the Miami Canal, also at the Palm Beach Broward County line, and in the northwest corner of Water-Conservation Area 3A. S-8, like S-7, has a sluice gate for water-level control, but it is equipped with four 895 hp diesel powered pumps. Their combined capacity is 4,160 cfs or 2,689 mgd. S-8 is designed to remove three-fourths inch of runoff per day from a 208-square-mile-area north of the county line and discharge it into Water-Conservation Area 3A.

S-9 is on the South New River Canal at its junction with Levee 33 and 37, half a mile west of U. S. Highway 27. S-9 has three 1,655 hp diesel powered





































Figure 6. FCD S-7 (pump Station) on the North New River Canal at the Palm Beach Broward County line.






BUREAU OF GEOLOGY


pumps with a combined capacity of 2,880 cfs or 1,860 mgd. S-9 is designed to remove three-fourths inch of water per day from the drainage areas of South New River Canal and the L-33 and L-37 borrow ditches, an area of approximately 71 square miles, and discharge the water into Water-Conservation Area 3A.

S-13 is on the South New River Canal west of U. S. Highway 441 and upstream from the Dania Cut-Off Canal. It has an electrically operated lift gate for normal regulation and salinity control and three 275 hp diesel powered pumps with a combined capacity of 540 cfs or 349 mgd. S-13 is designed to remove three-fourths inch of water per day from a 27-square-mile drainage area of South New River Canal and, unlike the other pump stations, it discharges water to the ocean.

HYDROLOGIC CHARACTERISTICS OF PRIMARY CANALS
AND WATER-CONSERVATION AREAS

The collection of data on canal stage and discharge in Broward County began on a small scale early in the 1900's (Grover, 1915). The regular collection of surface-water data in southeastern Florida was begun in 1939 (Parker and others, 1955) by the U. S. Geological Survey (figs. 7, 8). The data-collection network in southern Florida was expanded during the early 1950's in cooperation with the FCD. At the start of the present investigation in Broward County (1962), 17 additional data-collection sites were established. Several of the discharge stations were equipped with recording deflection vanes, which make possible a continuous accounting of the amount and direction of flow.

Surface-water data are published annually in reports of the Geological Survey entitled "Water-Resources Data for Florida."

HILLSBORO CANAL

The Hillsboro Canal (figs. 5 and 8) is one of the major drainage arteries constructed by the EDD in a land-reclamation program. The canal, 52 miles long, extends south and east from the southeast tip of Lake Okeechobee to the ocean. At its upper extremity it is joined by North New River Canal in a common pool, where flow into and out of the lake is regulated by Hurricane Gate HGS 4 and S-2. Twenty-two miles downstream from the lake, S-6 aids in lowering water levels in the agricultural area around the lake when runoff is excessive. Water removed from the canal at S-6 is transferred into Water-Conservation Area 1. In Area 1, the canal acts as a collector and distributor for the gravity interchange of flow between Area 1 and Area 2. Flow is regulated also at S-39 which has a gated control. Flow released at S-39 enters












REPORT OF INVESTIGATIONS NO. 65 17






ItI5,Ls0oo1 CANAl. S39, Nr, (e Irfield Beach (upper) 2113 U.S. IIII;RdAY 4I Nr. Deerfield Beath 2-2814.35 II.LSBORO CANAl. Or Deerfield Beach (auK) 2815.01 III LIUBORO CANAL Nr, Deerfield Beach (Base) 2815 IIILLSBORO RIVER at Deerfleld Beach 2816.5

POMPANO CANAL rd S-38, Nr. Pompano Beach 2817

POMPANO CANAL Pompano Beach
2820

CYPRESS CREEK ci S-37A Nr. Pompano Beach 2821

INTRACOASTAL WATERWAY @ Lauderdale By the Sea 2823 MIDDLE RIVER CANAL (d S-S6, Nr. Ft. Lauderdale (upper) 2827 VIIIOLL RIVER CANAL (a 5-36. Hr. Ft. Lauderdale (lower) MIDDLE RIVER CANAL @ U.S. Highway B Nr. Ft. Lauderdale 2828 PLANTATION RD. CANAl. r S-33, Nr. Ft. Lauderdale (upper) 2832 PLANTATION RD. CANAL N S-3), Nr. It. Lauderdale (lower) 2832.03 NORTII NEW RIVER CANAL abv. S-34, Hr. Ft. Lauderdale (aun. to 2847)

NORT1 NEW RIVER CANAL below S-34, Or. Ft. Lauderdale 2847

NORTH NEW RIVER CANAL Nr. Ft. Lauderdale (upper) 2850

BlIITII BEW RIVER CANAL Nr. Ft. Lauderdale (lower) (au.) 2858.01

S(THI NEW RIVER CANAL S 5-9, Nr. Dave (nux. to 2854)

SOUTH NEN RIVER CANAL d 5-9,. Nr. Davie (East of S-9) /,

SOUTH NEW RIVER CANAL Hr. Dvle SOUTH NEW RIVER CANAL rd S-13 Nr. Davie (upper) 2861

SUTII NEW RIVER CANAL Ni S-13 r. Davie (lover) (sux to 2861)
INTRACOASTAL WATERWAY (d Port Everglades
at Ilol lywood 2861 45 1

NCW AIVER 'd Ft. Lauderdale 2861.4 EXPLANATION IOLLYWOOD CANAL Bania 2861.5 DAILY STAGE 2861. DAILY DIAGE INTRACtIASTA). WATERWAY Vi Ilollywood 2861.6 DAILY DISCHARGE


SNAKE CREEK (A S-30 Nr. Ilaleah 7861.8 SNAKE CREEK CANAL A' NW. 67th Avenue Nr.
Il-al eh 2862

SNAKE CREEK CANAL Nl S-29, () North Miami
Beach (upper) 2863







Figure 7. Periods of record at selected surface-water data-collection stations in Broward County.






BUREAU OF GEOLOGY


EXPLANATION
CANAL ANO CONTROL STRUCTURE
LEVEE
V
SURFACE-WATER GAGING STATION


Figure & Location of surface-water daily data-collection stations in Broward County.
Broward County 10 miles west of Deerfield Beach (fig. 8) and travels east to the lock and dam near Deerfield Beach where it is again regulated.

Flow in the canal is affected by several lateral canals and unnumbered pumping stations in the urban and agricultural areas between S-39 and the coast (fig. 8). Canal E-1 of the Lake Worth Drainage District enters Hillsboro Canal from the north at U. S. Highway 441. Drainage into Hillsboro Canal is regulated






REPORT OF INVESTIGATIONS NO. 65


by a control structure and irrigation water is pumped into Canal E-1. A similar canal extending southward along U. S. Highway 441 also is equipped with a control structure and irrigation pumps. Canal E-2 of the drainage district has been integrated with the Florida Turnpike ditches. Gravity flow into Hillsboro Canal from these ditches is regulated by small control structures.' A small controlled canal, 1.4 miles west of the Deerfield lock and dam, drains the urban area south of the canal and another controlled canal, 0.1 mile upstream from the lock and dam, regulates flow between the Hillsboro Canal and Canal E-3. Flow beyond the dam is unobstructed to the ocean.

Average 30-year discharge at the Deerfield lock and dam is 365 cfs or 264,200 acre-feet per year. Daily discharge was maximum, 3,490 cfs, on October 12, 1947 and water level above the dam was highest, 12.58 feet above msl, on December 24,1957. Land along the canal in Broward County is about 13.5 feet above msl and there has been no evidence of overbank flow above the dam.

Flow to the sea through the Deerfield lock and dam varies generally with rainfall and the resultant opening of the control, except that after wet periods excessive runoff lasts several months into the next year (fig. 9). Discharge in relation to rainfall decreased during the late 1950's after the effective closing of Conservation-Areas 1 and 2A by levees 40 and 36 and structure S-39. After 1961, most of the flow through the lower reach of the canal during rainy periods consisted of runoff from the coastal area, ground-water inflow, and levee seepage. When rainfall is heavy the opening of controls on the lateral canals east of U. S. Highway 441 can impose large sudden runoff loads on Hillsboro Canal.

POMPANO CANAL (C-14) AND CYPRESS CREEK CANAL

The Pompano Canal (fig. 8) was constructed by the EDD during 1906-27. From its mouth at the Intracoastal Waterway it extends 2 miles northwest to Pompano Beach, and then 11 miles west to S-38 at Levee 35A. There, the flow is normally eastward, but frequentlly reverses. Flow moving eastward is augmented by inflow from several laterals to the north and the canal is joined 3 miles west of Pompano Beach by the Cypress Creek Canal. At this point, depending on regulation, flow either continues eastward in the Pompano Canal or is diverted southeastward in the Cypress Creek Canal. Flow continuing in the Pompano Canal is subject to further regulation at controls 1 mile and 3 miles downstream; east of the latter control, flow is unobstructed and generally subject to tidal fluctuations. Before September 1967, flow in the canal was measured daily 150 feet east of S-38. Maximum daily positive seaward flow at S-38 (1962-67) was 707 cfs on August 8, 1966 and maximum daily reverse flow was 220 cfs November 4, 1966. Maximum daily flow recorded at Pompano Beach was 470 cfs on November 1, 1965, 1 day after a maximum stage of 5.91 feet above msl.







BUREAU OF GEOLOGY


STATUS OF THE CONTROL STRUCTURE
0 PARTLY OPEN E CLOSED
I. V 11 1 11t


00
2 -: 0
w401


I IDISCHAR E AT S-39


Ti I I I I I I I I I I I I I I I
20 RAINFALL




940 45 50 55 60 65 1970
Figre 9. Monthly mean discharge and monthly extremes in stage in the
Hillsboro Canal at Deerfield Beach (2815) and S-39 (2813), average monthly rainfall at Belle Glade and Pompano Beach, and
a record of gate operations for the periods of record.

On some days no flow occurs at Pompano Beach station. Flow in the Cypress Creek Canal is regulated by S-37B and S-37A (fig.8).

Most of the flow from inland reaches of the Pompano Canal (fig. 10) is diverted through the Cypress Creek Canal. Comparison of the flow through S-38 and the control structures near the coast in both canals indicates considerable runoff or ground-water inflow from the urban and agricultural area east of the conservation area.


STAGE T 1 1 I I I I STAGE At DEERFIELD BEACHII








REPORT OF INVESTIGATIONS NO. 65 21


STATUS OF THE CONTROL STRUCTURE E] OPEN [ PARTLY OPEN U CLOSED




9 POMPANO CANAL AT S.311 (LOWER) ' MAXIMUM ,


]\INMU _


J ff1 U)W i- 4




-In





,;w 0u


u,,i .. MAXIMUM ',

2 -MINIMUM
I CYPES CREEK CANA AT U


800 1l I 1 I

700 CYPRESS CREEK CANAL AT S-37A o 600

4n 500

CC w
L w 300

L IO
a200
I100 -r

01
[ OPEN 0 PARTLY OPEN U CLOSED



J
I 6 POMPANO CANAL AT POM 1PANO BEACH' (UPPERI IIMAUXIMUMj


40 3

0
a 120 POMPANO CANAL AT o POMPANO BEACH U100

" 80 STATION ID [DISCONTINUED



40

1963 1964 1965 1966 1967 1968 1969 1970



Figure 10. Monthly mean discharge and monthly extremes in stage in the

Pompano Canal at Pompano Beach (2820) and at S-38 (2817) and in Cypress Creek Canal at S-37A (2821) with a record of
gate operation for the periods of record.


70 u- -- --- I I I
600- POMPANO CANAL AT S-38 500

400
STATION DISCONTINUED 300

200

100

0 .

AUTOMATIC DAM






BUREAU OF GEOLOGY


MIDDLE RIVER CANAL (C-13)

Middle River Canal extends eastward from Canal C-42, near Conservation Area 2B, to the Intracoastal Waterway through the northern part of the Fort Lauderdale area (fig. 8). Seaward flow in the canal is regulated by S-36, 1.5 miles east of U. S. Highway 441 and 5 miles west of the Intracoastal Waterway. Approximately 1.5 miles downstream from S-36, the canal enters the headwaters of the South Fork of the Middle River. Flow downstream of the control structure is subject to tidal fluctuations.

A by-pass feeder canal is connected to the north side of the Middle River Canal I mile west of the control structure. Flow in the feeder canal replenishes the aquifer in the area of the Prospect well field of the city of Fort Lauderdale.

Proposed modifications to the Middle River Canal system include the connection of Canal C-42 with the levee system on the east boundary of Conservation Area 2B and the improvement of the channel in the western reach of the Middle River Canal. Completion of this construction will enable more water to flow eastward in Middle River Canal during dry periods to replenish the aquifer in coastal areas. Flow in the Middle River Canal is small (fig. 11) because of its poor connection to the regional canal system.

NORTH NEW RIVER-PLANTATION CANALS
North New River Canal is one of the major drainage arteries constructed by the EDD in its program to reclaim the upper Everglades (p. 34). It is 60 miles long (fig. 5) extending from the lower eastern tip of Lake Okeechobee, south and east to New River and thence to the ocean (fig. 8). At Lake Okeechobee its headwaters join those of the Hillsboro Canal, and like the Hillsboro, the interchange of flow between the lake and the canal is regulated by HGS 4 and S-2. Thirty miles downstream from the lake, at the Broward Palm Beach County line, the canal is joined by Levee 5 and Levee 6 Canals (fig. 5). There, flow is regulated by S-7, which expedites the removal of flood waters from the agricultural area to the north, and transfers the excess runoff into Conservation-Area 2A.
Inside Area 2A the North New River Canal is divided into an upper and lower segment; the upper is cut off from the lower by levees and the lower (fig. 8) acts as a collector and distributor for flow between 2A and 3A. Water released from Area 2A must pass eastward through S-34. Along the southern perimeter of Area 2B, flow is augmented by seepage and by inflow from several lateral canals as it travels some 14 miles to the Sewell Lock (fig. 8). The perimeter canal outside of Levee 35A, the east boundary of 2B, joins North New River Canal about 5 miles east of S-34.




Monthly mean discharge and monthly extremes in stage in the Middle River Canal at S-36 (2827) and a record of gate operations, 1963-70.



STATUS OF THE CONTROL STRUCTURE


[] OPEN go PARTLY OPEN


E CLOSED


0 1 1 O- DISCHARGE AT S-36 0o

0

o
r) -C n r1rJ I r l


-j
w, 6 wi 5 w' 3
LL
z
0


25
z
020

w

0. 10 w 5
w
LL


ON FR F// MW '4 'orm H "H .


19635 1964


1965 1966 1967 1968


1969 1970







BUREAU OF GEOLOGY


Levee 35A Canal and Canal C-42 (fig. 8), 5 miles to the east, drain a recently established residential area on the north side of North New River Canal. Flow into North New River Canal from the Levee 35A Canal is regulated. The northern extension of Snake Creek Canal (Flamingo Road Canal) is connected to North New River Canal by a gated culvert under State Road 84, 8 miles east of S-34. Water control for two separate urban areas is provided by canals and pump stations north of the lower reach of North New River Canal. Water levels in the west urban area, 3 miles west of Sewell Lock, are controlled by a 245-mgd pump station established in 1969 by the developer. The east development is part of the Old Plantation Water Control District which includes the city of Plantation and was probably the earliest community in Broward County dependent on controlled water levels. Water in the district is controlled chiefly by the Holloway Canal and a 260-mgd pump station and control structure which is designed to pump or drain into North New River Canal downstream of Sewell Lock. At the Sewell Lock flow in the North New River Canal is subject to further regulation as it passes through the eight spillways controlled by stoplogs. The lock chamber is permanently closed by an earthen dam. Flow beyond of South New River Canal and acts as a divide between the drainage areas of S-9 and S-13.

Hydrographs for North New River Canal (fig. 12) indicate that flow during 1940-60 was related almost entirely to rainfall and the resultant runoff. During the 1960's a reduction of seaward flow resulted from the use of S-34 to hold water in storage in the conservation areas. During this period the flow through Sewell Lock was derived chiefly from runoff east of the levees, ground-water inflow and seepage along L-35 and L-35A.

The North Fork New River extends, as an improved natural waterway, about 3 miles northwest from the junction with New River, then joins the Plantation Canal (C-12) which extends westward to Holloway Canal. Flow in Plantation Canal is regulated by S-33, 0.5 mile east of U. S. Highway 441. Seaward flow in Plantation Canal at S-33 (fig. 13) is generally low because the area drained by the canal is small. During low flow effluent wastes concentrate in upstream reaches of the canal and stagnant conditions prevail. Construction is underway to connect the upstream reach of Plantation Canal with Middle River to provide adequate flow from the management system.

SOUTH NEW RIVER CANAL (C-11)

The South New River Canal begins at the Miami Canal in Conservation Area 3A in western Broward County (fig. 5) and flows due east for 23 miles to the junction with the Dania Cut-off Canal and the South Fork New River (fig. 8). The South Fork New River flows northeastward and joins the New River








REPORT OF INVESTIGATIONS NO. 65


system; the Dania Cut-off Canal continues eastward to the Intracoastal Waterway. Numerous drainage and irrigation canals and ditches enter the South New River Canal from both the south and north sides along the reach between the Florida Turnpike and Levee 33 (fig. 8).- East of the Turnpike, along the Dania Cut-Off Canal, numerous navigable canals have been connected to develop waterfront property. The Hollywood Canal (C-10) flows northward about 3.5 miles and enters the Dania Cut-Off Canal less than a mile west of U. S. Highway


STATUS OF THE CONTROL STRUCTURE
[] OPEN [j PARTLY OPEN OR SPILLING CLOSED
S-34 -i M9


40 . ..DI S C . . R I I A I .I I I I I 1
40 DICAREATS3
r1) 1 1 1 1 1 1 1 1 1 1 1 I A I I I h. II A I I


IIIIiI/IIllhfIIIIIllhIIIIjI'I'Ufl/lIfl. hi/fill St WtLL LU(.K "I 1/ El I/i/i / U', 'flL/fiflli'IIIEIIIN, iN, hE


20 1 1 R I I I I

15
10
1940 45 50 55 60 65 1970

Figure 12. Monthly mean discharge and monthly extremes in stage in the
North New River Canal at Sewell Lock (2850) and S-34 (2847), the average monthly rainfall at Fort Lauderdale, Belle Glade and Dania, and a record of gate operations for the periods of record.


IIII//IIIII/III~i41'I][;I/i':,71//SI'ELL LO XK'.' j'l~/,s" i!'Tilil/l,'ii?


;" '/ llN/,'l//,l!lllVlfl, lffl/lff, '/,','.'l,"/Jl






STATUS OF THE CONTROL STRUCTURE

OPEN PARTLY OPEN *CLOSED I
--I


u J ,I
SI STAGE AT S-33 (UPER) -MAXIMUM







,04 70 1
a0







1963 1964 (965 (966 1967 (968 1969 (970
(Li








REPORT OF INVESTIGATIONS NO. 65


The direction and amount of flow of South New River Canal are regulated by three control structures. S-9, about 0.5 mile west of U. S. Highway 27, is the only back-pumping station on the southeast boundary of the conservation areas. The pumping station is designed to remove flood waters from 71 square miles along the canal and discharge it into Conservation Area 3A for use during dry periods. Pumping station S-13, west of U. S. Highway 441, is designed to assist gravity flow by pumping seaward during flood periods and to regulate discharge during dry periods. Control structure S-13A regulates flow in the central reach of South New River Canal and acts as a divide between the drainage areas of S-9 and S-13.

A fourth control is located 0.25 mile east of U. S. Highway 441 at the Florida Power and Light Company's power plant. The power plant withdraws water from the Dania Cut-Off Canal for cooling condensers. The control retards salty tidal water from entering the intake area.


The dissimilarity between the hydrographs at S-9 and S-13 (fig. 14) is the result of the operations of the two pumping stations and the regulation at S-1 3A. When rainfall is excessive S-1 3A is closed and S-9 diverts water westward to Conservation Area 3A; at the same time pumping at S-13 assists gravity flow eastward to the ocean. During the growing season when irrigation water enters the western reach of the canal, S-13A is closed, S-9 diverts water westward to Conservation Area 3A and flow to the ocean east of S-13A is by gravity flow. When S-9 is not pumping and S-13A and S-13 are partly or completely open, flow is seaward throughout the entire reach.


SNAKE CREEK CANAL (C-9)

Snake Creek Canal, the primary drainage channel for the coastal area along the Dade Broward County boundary (fig. 8), forms the south hydraulic boundary for Broward County. Flow in the canal is maintained chiefly by ground-water inflow, however, considerable surface runoff is introduced during rainy periods and water can be introduced from the conservation areas by manipulating S-30, 0.75 mile east of Levee 33. Submerged sluice gates at S-29 are manipulated to provide maximum discharge for flood protection during heavy rainfall and to prevent sea-water intrusion into the aquifer and into the upper reaches of the canal during dry periods. The hydrographs in figure 15 indicate that as much as half the flow at S-29 is derived from ground-water inflow or from lateral canals from Broward County upstream from the gaging station at 67th Avenue. Little water enters the canal from Conservation Area 3 except by levee seepage.









28 BUREAU OF GEOLOGY


PUMP STATUS AT S-9
0 INTERMITTENT PUMPING NOT PUMPING IIi, : ,:. , ;: 4;i,$ / ,///// / /Z /, ///////////,
:2| I I I I I I i -wto 9
8 MINIMUM



6C0 ISCHARGE AT S-9
0



400

t300
200

SO"
STATUS OF THE CONTROL STRUCTURE AT S-13 [ :: ;" '!I ///:!l,/ ,,///i,./7/7/7/ 1//,/, // ///
~ TGEAMSII(PER NIMUM

STAGEAT S-3A (UPEP MINIMUM II







5O I I r.l zO DISCHARGE AT S-93
4W 00




4 I
W 00







4- I i I II /
C









1 963 1964 1965 1966 1967 1968 1969 1970

Figure 14. Monthly mean discharge and monthly, extremes in stage for South New River Canal at Pumping Stations S-9 (2854) and S-13 (2861) with a record of gate operations, 1963-69.

EFFECTS OF WATER MANAGEMENT


As the water-management system has become more efficient, the extremes in flow have been greatly modified and the duration of moderate or optimum flows greatly lengthened. Long-term discharge records for Htilisboro and North New River Canals (figs. 9 and 12) show major changes in flow characteristics with changes in the status of the management system in the late 1950's. For example, double-mass curves for the two canals (fig. 16) show a striking deviation from a straight line relationship after 1960, when most of the FCD










REPORT OF INVESTIGATIONS NO. 65


STATUS OF THE CONTROL STRUCTURE E] OPEN PARTLY OPEN U CLOSED


7- STAGE A1II S-30 (UPPERs -MAXIMUM
5 MINIMUMM B o I 600 DISCHARGE AT S-30

400JLI STATION DISCONTINUED





800
60

400
200



STAGE AT S-29 (UPPER~)MAMU
2 -MINIMUM
I I


1963 1964 1965 1966 1967 1968 1969 1970

Figure 15. Monthly mean discharge in Snake Creek Canal at S-30 (2861.8),
67 Avenue (2862) and S-29 (2863), monthly extremes in stage above S-29 and S-30, and a record of control operations for the
periods of record.

system in southern Florida was complete and management efforts were intensified. Leach and others (1970) found that little or no runoff occurs if annual rainfall is less than 37 inches and that runoff caused by the seasonal rainfall is best portrayed by a runoff year of April 1 through March 31. Thus, cumulative rainfall exceeding 37 inches was plotted against cumulative discharge for each runoff year.


The change in the slope of the curves indicate reductions in the amount of water discharged to the ocean. The amount of the reduction is indicated by the








BUREAU OF GEOLOGY


horizontal distance between the extension of the original curve and the deviated curve as indicated by the example in the upper right-hand comer of each graph of figure 16. The reduction averaged 260 cfs for the 13-year period on Hillsboro Canal and 375 cfs for the 8-year period on North New River Canal or about 188,000 and 271,000 acre-feet per year, respectively.


Changes in the flow system are also indicated by the flow-duration curves for the Hillsboro and North New River Canals, (fig. 17). The periods 1941-53 and 1962-68 were chosen because 1941 represents the time when records were started and 1953 the time when the first of the facilities of the water-management system were begun; 1962-68 represents the period after which the system was virtually complete in the Broward County area.


The upper part of the curve for the Hillsboro Canal shows that water management has had little effect on peak flows. However, in the moderate flow range the curve shows that a discharge of 260 cfs was equaled or exceeded 50 percent of the time in the early period but was reduced to about 80 cfs for the same percentage of time in the later period. The crossing of the curves in the lower parts indicates that in the dry part of the year control operations have maintained higher flows in the later period than in the early period.


The curve for the North New River Canal shows a marked reduction in the peak flows since completion of the water management system. Also, the moderate flows in the North New River Canal have been more affected by water management than in the Hifisboro Canal. For example, in 1941-53, a discharge of 450 cfs was equaled or exceeded 50 percent of the time, whereas in 1962-68, a discharge of about 110 cfs was equaled or exceeded for the same percentage of time. The lower ends of the curves are similar to those of the Hillsboro in that the 1962-68 curve flattens and crosses the 1941-53 curve indicating that higher flows have been maintained in 1962-68 during the dry parts of the year.


The flow characteristics of the six remaining primary canals in Broward County (fig. 18) are different from those of figure 17. Normally the slope of the flow-duration curve indicates the variability of flow of the stream; the steeper the slope, the more variable the flow. A flat slope usually indicates the stream is receiving water from surface-water storage during high flow and from ground-water storage during low flow. Because in southeastern Florida almost all canals are controlled at several points along their reaches, the flow-duration curves of the canals shown in figure 18 indicate primarily the characteristics of management and not of the canal basins.








REPORT OF INVESTIGATIONS NO. 65 31






A 3400 CUBIC FEET PER SECOND REDUCTION IN DISCHARGE _FOR PERIOD 195770 (AVERAGE ABOUT 260 CUBIC I970O
FEET PER SECOND PER YEAR)
600


400

z HILLSBO0R0 CANAL



N 3000 CUBIC FEET SECOND REDUCTION IN DISCHARGE
FOR PERIOD 1962-70 (AVERAGE ABOUT 375 'CUBIC O)
- FEET PER SECOND PER TEAR)


400 D


200 0 NORTH NEW NIV/ER CANAL 1945
1940
0





0 2000 4000 6000 6000 I0,O00 120000 14P:00 16.000 1500O0 201000 ATIVE ANfjjAL DISCNA E.CuSIC FEET PER ECOND fro the Figure 16. C.umulmive runo z-year cuscnarge to tlhe ocean fo h
H-illsboro and North New River Canals plotted against cumulative mean annual rainfall (above 37 inches/year) at Belie Glade, Fort Laderdale, Dania and Pompano Beach (after Leach and others, 1970).




The curves in figure 1 8 show that as a result of water management flow occurred in most of the canals more than 75 percent of the time during the period of record. During the no-flow period and for a significant part of the flow period, the canals were recharging the aquifer in coastal areas where ground-water levels were low. The wide range of discharges during peak flows represented by the upper end of the curve is caused by a combination of size of drainage area, water-management operations at the conservation-area boundary, and the land elevation in the drainage area. Plantation Canal has the lowest peak discharge for the period. of record mainly because of its small drainage area and lack of connection with any primary canal (see fig. 8), Conversely, Snake Creek









32 BUREAU OF GEOLOGY 5000






HILLSBORO CANAL
,ooo _1000



5000 500

z
0
CL

or

O 10003 100 LU Lii w_' 500_-- -"50 um.
CL


w0 -r aw
UU
U 0 I



0 10010 X NORTH NEW RIVER CANAL 2i 50 15


0 1941-53 o 1962-68


0.01 0.3 0.5 I 2 5 10 50 90 99.5 99.99 PERCENTAGE OF TIME DISCHARGE EQUALED OR EXCEEDED THAT SHOWN


F'gure 17. Flow-duration curves for Hillsboro and North New River Canals,
1941-53 and 1962-6&







DISCHARGE,CUBIC FEET PER SECOND


0E




p..


0
p.



C,






BUREAU OF GEOLOGY


Canal had the highest peak discharge because of its large, low-lying drainage area which required flood peaks to be removed quickly, and releases from Conservation Area 3B through control structure S-30. Cypress Creek Canal had high peak flows because it receives most of the water from the Pompano Canal drainage area which also channels water from Conservation Area 2A to the ocean. Thus, the peak discharge of the Pompano Canal at the city dam in Pompano Beach is considerably less than the peak discharge of the Cypress Creek Canal at S-37A.

Curves for the Snake Creek, Cypress Creek and Pompano Canals (fig. 18) are similar because all three waterways have large drainage areas and are connected to the Conservation Areas. The similarity suggests that control procedures on all three canals are similar. However, control procedures on South New River and Plantation Canals are different. The gentle slope of the South New River Canal curve results from intense control of a large low-lying drainage area connected to Conservation Area 3, whereas the gentle slope of the Plantation Canal curve is the result of a small drainage area with a minimum of control at S-33. The slope of the curve for Middle River Canal is unique in the flow system of Broward County. Although the peak flow of the canal is about average for the flow system, its slope is the steepest and its percentage of virtually no flow is the largest. Because of the possibility of flooding in the urbanized part of the Middle River Canal drainage area, peak flows are rapidly removed. However, flow decreases rapidly because of poor connection with the Conservation Areas and the control structure at S-36 is closed to hold water levels high enough to provide replenishment to the nearby Fort Lauderdale Prospect well field.

Low-flow frequency curves for both the Hillsboro and North New River Canals, 1941-1953 and 1962-1968 show that the discharges for all durations have decreased considerably in the short recurrence intervals (figs. 19, 20). The discharges for the longer intervals for all durations for the Hillsboro Canal have increased, indicating that higher discharges have been maintained during low-flow periods following the implementation of the water management system. In contrast, the curves for the North New River Canal indicate that discharges have been reduced for all intervals and all durations. Although the two periods are of different lengths, generalizations related to changes in flow may be made by a comparing data.

Water that flows seaward from the conservation areas constitutes an important part of the water supply available for use in eastern Broward County. The water is derived from storage in the conservation areas or is imported from upgradient in the FCD system from Lake Okeechobee or the Kissimmee River. The water enters eastern Broward County, either by regulated releases into








REPORT OF INVESTIGATIONS NO. 65 35

5001 1 1 1 1 1 EXAMPLE:FOR A 2-YEAR RECURRENCE INTERVAL THE 7-DAY MINIMUM FLOW IS ABOUT 27 CFS AND THE 90-DAY MINIUUM FLOW IS ABOUT 120 CFS





50






1941-53
1O_

90 DAYS
5 30 DAYS
0
wu 7 DAYS

U
w
w
00
5O. I I I I I I I!

50. I II I I I I I I I I

EXAMPLE: FOR A 2-YEAR RECURRENCE w INTERVAL THE 7-DAY MINIMUM FLOW IS ABOUT 20 CFS AND THE 90-DAY MINIMUM FLOW IS 70 CFS

C100


50

90 DAYS



196 2-68

10 30 DAYS
7 DAYS

5






S I I I I I I I I I I I

1.01 1.051.1 .2 1.5 2 3 4 5 7 10 15 20 50 100 RECURRENCE INTERVAL ,YEARS

Figure 19. Low-flow frequency curves for the Hilsboro Canal, 1941-53 and
1962-68.








36 BUREAU OF GEOLOGY
o0

EXAMPLE:FOR A 2-YEAR RECURRENCE INTERVAL THE 7-DAY MINIMUM FLOW IS 78 CFS AND THE 90"DAY MINIMUM FLOW IS











20 __A5
90 DAYS
30 DAYS
7 DAYS

LU
LuI I I I I II I I I I
WJ I
Lu
o: i t I I i I I I

EXAMPLE1FOR A 2-YEAR RECURRENCE INTERVAL THE 7-DAY MINIMUM FLOW IS 78 CFS AND THE 90DAY MINIMUM FLOW IS 70 CFS

100 ...


50




90 DAYS

10 7_5



30 DAYS

1 7 DAYS
1.01 1.05 0 L2 1.5 2 3 4 5 7 10 20 50 100 RECURRENCE INTERVALYEARS
Figure 20. Low-flow frequency curves for the North New River Canal, 1941-S3 and 1962-68.







REPORT OF INVESTIGATIONS NO. 65


primary canals, or by seepage along the levee system. Regulated releases through structures S-34, S-38 and S-39 averaged 39, 47, and 41 cfs respectively for 1963-67.

Seepage rates along the levee system vary widely because of differences in the permeability of the shallow subsurface materials underlying the levees. Approximate rates of seepage may be determined using head discharge ratings from the U. S. Corps of Engineers and generalized heads across the levees. Leach and Klein (1970) estimated an average annual seepage for the 1963 water year of 8 efs per mile of levee from Conservation Areas 2A and 2B and 9.6 cfs per mile from Conservation Area 3B. This indicates that eastern Broward County received about 186,000 acre-feet of fresh water in 1963 from seepage along the 30 miles of levees bordering Conservation Area 2 and 3. Some of this seepage moves eastward through the aquifer, and some enters the perimeter canals outside the levee system and is conveyed to the nearest primary canal. However, flow in the perimeter canals Is controlled at several points to reduce seepage and to regulate releases into the primary canal system.

The control of water levels in eastern Broward County has been a major part of the water-management program of the FCD and the Broward Water Resources Department. The effects of both flood and drought have been almost completely alleviated as indicated by the urban development which extends inland to the conservation areas and by the stabilization of the salt front despite a manyfold increase in withdrawls from well fields upstream of coastal control structures. Occasional local flooding does occur because of intense short-term rainfall and lack of adequate secondary canals in some low-lying areas. In view of the occurrence of intensive rainfall such as the 25 inches recorded at Ft. Lauderdale on October 14-15, 1965, it may not be feasible to completely prevent minor flooding.

The extremely close control of water levels in the low areas of south Broward County by the South New River Canal and pump stations S-9 and S-1 3, provide a good example of both flood control and water conservation. Because of the low land altitude in the area, drainage is required much of the time. However, the back pumping facilities at S-9 permit the storage of much of the water removed; S-13 pumps seaward only during extreme flood periods and during most of the year permits drainage of the highly urbanized area east of S-13A by gravity flow. For the period 1963 to 1968 shown in the discharge hydrographs (fig. 14), the average annual flows seaward and .into the conservation area were 164 cfs and 140 cfs respectively. The annual average flow to the conservation area increased steadily from 60 cfs in 1963 to 206 cfs in 1968.










BUREAU OF GEOLOGY


80*00


INLET


LAUDERDALE BY-THE-SEA


BAKERS HAULOVER CUT


DADE COUNTY


MIAMI BEACH MIAMI BEACH


a 5 MILES


Figure 21. Location of recording tide gages in the Intracoastal Waterway.


BROWA


SURVEY


8015.,'







REPORT OF INVESTIGATIONS NO. 65


INTRACOASTAL WATERWAY

The Intracoastal Waterway (fig. 21) borders the coast in Broward County and is separated from the ocean by a narrow offshore bar locally known as the beach. Tidal interchange between the waterway and the ocean is through the relatively narrow Port Everglades and Hillsboro Inlets in Broward County, Boca Raton Inlet in southern Palm Beach County and Bakers Haulover Cut in northern Dade County.


Tidal interchange between the ocean and the waterway through the Port Everglades Inlet and then northward along the waterway is good. Seaward flow from all the primary canals discharges into the waterway. Fresh water entering the waterway from the mainland canals affects the water levels and salinity in the waterway during high fresh-water discharge.


The Intracoastal Waterway is used extensively for boating and water sports and shipping in Port -Everglades. In addition, some of the most intensely developed urban and tourist areas in the nation border its 30 miles of low lying shoreline.

Tidal data are available from four stations in Broward County and from the U. S. Coast and Geodetic Survey Primary Tide Gage at Miami Beach (fig. 21). Tidal data are also available from stations maintained by the U. S. Geological Survey or the Flood Control District at the salinity control structures on the primary canals (fig. 8).


The tidal ranges at Port Everglades and Lauderdale by-the-Sea are comparable with the range at Miami Beach (table 2). The range at Deerfield Beach is less because of the distance from the nearest inlets and the small size of the inlets. The range at Hollywood is less because of channel constrictions and the distance from an inlet. Typical tidal fluctuations at Port Everglades, Deerfield Beach and Hollywood are shown in figure 22.

The seasonal variation of monthly mean high water was less than 0.1 foot along the waterway (fig. 23). The tides were highest in September and October, the prime hurricane season. The elevation of mean half tide was higher along the waterway than at Port Everglades Inlet due primarily to an increase in the height of mean low water. The maximum difference between mean half tide (the average of mean high and mean low waters) and mean water level at the five stations was found to be 0.03 foot during the investigation.






Table 2. Mean values of high and low water, tidal range, half tide and time difference observed in the
Intacoastal Waterway March 1, 1968 through February 28, 1969 (Schneider, 1970, table 1)
MEAN I TIME DIFFERENCE 2 (feet) (hours & minutes) High Low Tidal Half STATION Water Water Range Tide High Tide Low Tide


Miami Beach Primary Tide Station (U. S. Coast and Geodetic Survey Station)

Intracoastal Waterway at Hollywood (2861.6)

Intracoastal Waterway at Port Everglades (2861.43)

Intracoastal Waterway at Lauderdale by-the-Sea (2861.43)


Hillsboro River (Intracoastal Waterway) at Deerfield Beach (2816.5)


1.58


1.53 1.58


1.61 1.52


-0.83


-0.27



-0.83


-0.75


-0.55


2.41 1.80



2.41 2.36 2.07


0.38 0.63 0.38


0.43 0.48


+1 30 +1 40


Negligible


Negligible


+1 00 +1 20 +1 00 +1 20


Notes: 'Datum is mean sea level, datum of 1929.
2 Referenced to Miami Beach station.








REPORT OF INVESTIGATIONS NO. 65 41









&,0 -1.0


0.0 LO
-J
w


INTRACOASTAL WATERWAY AT PORT EVERGLADES (-861.43)
-3.01

0




00


w W -L
W HILLSBORO RIVER AT DEERFIELD BEACH(2B16.5)

w

m 2.0


5 6 7 8 9 10 II 12 13 I, MAY 1968
Figure 22. Typical tidal fluctuations at selected sites In the Intracoastal
Waterway, May 5-14,1968 (Schneider, 1970, fig. 2).







BUREAU OF GEOLOGY


M A M J J A S 0 N D J F


1968


1969


Figu 23. Seasonal changes of the monthly mean high and low-tide and
half tide at selected sites in the Intracoastal Waterway (after
Schneider, 1970, figs. 3 and 4).


42

2


2.


I.


I.





.t
I1j


uJ




0



0

< 0
0

0 .
L>I
ZI

W


U '-0






<
0






REPORT OF INVESTIGATIONS NO. 65


To determine the time of high or low tide at a selected station, the correction shown in table 2 should be added to the time of predicted high or low tide at Miami Beach (U. S. Coast & Geodetic Survey Tide Tables). The time lag at Port Everglades was negligible. The time lags for selected stations (fig. 8) in the canal system are shown below.

TIME LAG


Hillsboro Canal Middle River Canal Plantation Canal North New River Canal South New River Canal


below control below S-36 below S-33 below Sewell Lock below S-13


, u I I I
MIAMI BEACH
U.S.CRAST a GEODETIC SURVEY
2.0 L A


JV


29 30 31 I 2
S OCT NOV zI

0
4.C
W
2
0. P0 rVRGAES(86,3
-j
co OCT.. NOV.



.0



430
Wtn-


29 30
OCT


V U


It.A7__


HOLLYWOOD (28161.6)


1 161.6) ____HAH~AHA


\LiJ


29 30
OCT


31 I 2 29 30 31


NOV


OCT


31 I 2
NOV


I 2
NOV


1969
Figure 24. Effects of strong easterly winds Oct. 29-31, 1969 on .tide
patterns at selected sites in the Intracoastal Waterway
(Schneider, 1970, fig. 5).


High Tide 1 h 00 m 1 h 30 m
35 m 1 h 40 m 2 h 10 m


Low Tide 1 h 45 m 2 h 00 m 1 h 15 m 2 h SO m 3 h 00 m


I I I I
HILLSBORO RIVER(2816,5) A- ,_1_A ) _A A


___V u


Lin i iv







BUREAU OF GEOLOGY


On October 29-31, 1969, a combination of seasonal high spring tides and strong easterly winds caused local flooding along the waterway. An onshore wind began blowing on October 29 and continued through October 31. On November 1 the wind veered to the south, then on November 2 to the west. The wind and the shift in direction caused the tide level to rise on October 29-31, then to decline on November 1 and 2 (fig. 24). These tides were relatively small in comparison to those expected from tropical storms. The highest tide recorded along the Broward coast since 1900 occurred during the 1926 hurricane and was 103 feet above mean sea level (U. S. Corps of Engineers, 1956). Other high tides were 9.8 feet (1947) and 8.8 feet (1935) above mean sea level.

At Miami Beach sea level has been rising for at least 35 years, at a rate of about 0.01 foot per year (fig. 25). The mean water level at Miami Beach for 1950-68 was 0.34 foot. The mean water level at Miami Beach during the investigation March 1, 1968 to February 28, 1969 was 0.38 foot.


Z 1930 1940 1950 1960 lai


Figure 25. Yearly mean water levels at Miami Beach, Florida, showing the
average rise in sea level (Schneider, 1970, fig. 6).


GROUND WATER

The two aquifers that underlie Broward County are the shallow Biscayne aquifer which is nonartesian and the deep Floridan aquifer which is artesian.


1970











REPORT OF INVESTIGATIONS NO. 65


o o F, zc m t, 0 o o o. o o. O J L L_ .t.....JJ...J L ffI W i


LAI


POMPANO CANAL



CYPRESS CREEK -,
CANAL G-1229 j


6- 1231


MIDDLE RIVER
CANAL G-1233 NORTH FORK 0 NEW RIVER


I-[ ,t FI- ,-I-F I--.I-


I I I II~iI I I-' I-' 1~1J; I:I~I~


II.;


IPTfr


4 SOUTH FORK
--7NEW RIVER
I SR.84

IG-1235

DANIA CUT-OFF
CANAL


(-123


i- I. I I I- I I -


.. .. ... ..


I(-- G-1241


I BROWARD CO.

~~UU1~III~1. )G-892k


I I I I I I I I I


Iw IP ro


IiL~


z








or'

-o
mg


C-I0 CANAL Rlhh I lUG-1346


G6-1352


B ]lI .]T]l MR' ] ',-'''' ', p


................... I J


It?.


.................................... %,, !.-


-G 1228

-G-1272


. . . . G-1240










46 BUREAU OF GEOLOGY


BISCAYNE AQUIFER


The Biscayne aquifer is the source of all fresh ground water in Broward County and is composed chiefly of limestone, sandstone and sand (figs. 26-28) of marine origin which range in age from (oldest to youngest) late Miocene through Pleistocene. The aquifer is generally more than 200 feet thick along the' coast in Broward County, and 350 feet at one point in Pompano Beach. The thickness of the consolidated limestone sections and the permeability of the aquifer as a unit geneially decrease to the north. The aquifer also thins westward to about 70 feet at U. S. 27 in central Broward County and wedges out at the surface near the Collier Broward County line.








8.C B
0 U S. FLORIDA!S US, 0 m
27TURNPIKE 441 LY co N
20 NO~r P NEW L-JSA CANAL C- 40 CtWAL '
RIVER CANAL /

SEA
LEVELE XPLANATION


SAND LIMESTONE SHELL

4O
CALCAREOUS CLAY.L SANDSTONE AND a 60 MARL 4:I=
4

80


100
0 I 2IMHs '20 .


140


160

ISO'- ]: '


200:

Figure 27. Lithologic logs along line B-B' in figure 29.











REPORT OF INVESTIGATIONS NO. 65


Most of the limestone beds in the Biscayne aquifer are capable of yielding large amounts of water to wells. Wells that tap the thick limestone.in the deeper part (100-foot depths or more) near the coast, commonly yield more than 1,000 gpm (gallons per minute). Most of the municipalities obtain water from the deeper part of the aquifer.


SAND LIMESTONE SHELL CALCAREOUS SANDSTONE


0.



3 0



M-,




















MARL OR CLAY


0 1 2MILES


Figure 28. Lithologic logs along line C-C' in figure 29.


0

2 0' 0


SEA
LEVEL--


180L


200'


R ,,j







BUREAU OF GEOLOGY


Figure 29. Location of test holes and lines of lithologic logs in eastern
Broward County.

RECHARGE AND DISCHARGE

Infiltration of rainfall through surface materials and seepage from controlled canals and the conservation areas are the principal means of recharging the Biscayne Aquifer. Recharge by rainfall is greatest during the rainy season from June to November. Recharge from canals is greatest during the dry season, December to May, when canal levels are higher than adjacent water levels








REPORT OF INVESTIGATIONS NO. 65


in the aquifer. Discharge from the aquifer is by evapotranspiration, by ground-water flow to canals and to the sea, and by pumping from wells. Discharge by ground-water flow and by evapotranspiration are greatest after periods of rainfall when water levels are high; discharge by pumping from wells is greatest during the dry season as a result of the influx of tourists and heavy irrigation use when water levels are low. Well yield is only a small part of the total discharge from the aquifer, but during the dry season its importance is amplified because it occurs when total recharge and aquifer storage are smallest.

The average annual rainfall of about 60 inches if distributed evenly over the county would be equivalent to about 3,400 mgd. Evapotranspiration from surface waters would return about 22 inches (1,250 mgd) to the atmosphere. Evapotranspiration from the water table would return an additional 20 inches (1,130 mgd) to the atmosphere (fig. 30). A very small part, probably little more than 1 inch (60 mgd), would run off directly to the canals. Of the remaining 17 inches of water that enters the aquifer less than 2.5 inches is withdrawn for use and about 14.5 inches is discharged to the sea by coastal canals (13.5 inches) or ground-water outflow (1 inch). These figures are highly generalized and do not take into account variations in rainfall due to both location and time and minor changes in aquifer storage. Also, although not shown in the diagram, water imported into the county by canals of the FCD system and introduced to the aquifer plays an increasingly important part in the total flow system.

The foregoing summary indicates that much more water flows through the aquifer than is withdrawn for all types of use. However, it should be noted that water use is concentrated near the coast where supplies are most limited and that conditions depicted in the diagram do no persist throughout the year; during extended dry periods, when withdrawals are greatest, the only recharge available is from canals of the water-management system.

WATER-LEVEL FLUCTUATIONS
Wafer levels in the Biscayne aquifer fluctuate over a wide range in response to recharge or discharge and to a lesser extent to other factors such as tides, earthquakes, and changes in atmospheric pressure. The greatest fluctuations, as much as 5 to 10 feet per day, are caused by recharge from rainfall and by pumping; but gradual changes in water levels caused by evapotranspiration and normal ground-water outflow have an important effect on the amount of water in storage in the aquifer.
Ground water is continually moving at rates dependent on the hydraulic gradient and the permeability of materials through which it moves. Ground water flows by gravity from areas of high water levels to areas of low water levels. In a restricted sense, low water levels are associated with discharge areas.









EVAPOTRANSPIRATION
42 INCHES


CANAL L







14 O.rA


.5 ~~ 14_5,WTERWA Fi 0 ia~a~prtaa o e~ t ad i- teB~ q nB20 out.














REPORT OF INVESTIGATIONS NO. 65 51



Water-level fluctuations were monitored by measurements in a network of more than a hundred observation stations on wells and canals; 47 of the stations Were equipped with automatic recording instruments (fig. 31).


25"


EXPLANATION

CANAL AND CONTROL STRUCTURE ROAD
SURFACE WATER OBSERVATION STATIONS
Y RECORDING V PERIODIC
OBSERVATION WELLS
RECORDING o PERIODIC


Figure 31. Water-level observation stations on wells and canals in Broward

County.








BUREAU OF GEOLOGY


Figure 32 shows that the long-term elevation of water levels in the coastal and uncontrolled canal areas is relatively constant. Although large seasonal fluctuations occur, the levels return quickly to the long-term elevation. This is characteristic of an area of natural discharge where the water-level fluctuations are moderated by surface runoff, and where ground water flows into uncontrolled reaches of canals and into the Intracoastal Waterway.

Figure 33 indicates that water-level fluctuations in wells in the inland intercanal areas are similar to those in wells in the coastal areas in that the long-term elevations do not show much of a rise or decline. However, the magnitude of seasonal and short-term fluctuations are smaller in the inland areas. This is a result of water-control practices of the FCD and the various drainage districts. By the operation of canal controls, excess water is removed more rapidly during wet periods and more water is retained during the dry season. The hydrograph of well G-616 indicates a long-term decline in water levels which occurred as the land was drained for urbanization.

Hydrographs of water levels in the wells in figure 34 show the effects of pumping of municipal water-supply wells. The effects of increased municipal pumpage are indicated not only by the long-term decline in water levels, but also by the increase in the magnitude of the seasonal fluctuations.

The record low water levels of May 5, 1971 (fig. 35) resulted from abnormally low rainfall of only 41 inches in the preceding 12 months and only 4 inches in the preceding 6 months. All coastal canal structures were closed to conserve fresh water for recharge to the aquifer. Also, voluntary restrictions on pumping were in effect in all major well fields. The heavy withdrawal of ground water is indicated by the closed depression contours. The contours indicate that the control structures on the Middle River and North New River Canals are too far inland to provide fresh-water canal reaches for recharge to the well-fields and to prevent salt-water intrusion from these tidal reaches. Figure 35 also indicates that water levels in the Hollywood Dania area are near sea level. Excessive drainage has occurred near the Hollywood well field by the uncontrolled discharge of the Hollywood Canal into the Dania Cut-Off Canal. The large ground-water mound in the northern part of the county resulted from recharge to the aquifer by water pumped from the Hillsboro Canal into a system of controlled irrigation canals and ditches.

The record high water levels of November 1, 1965 (fig. 36) resulted from the 81 inches of rain that fell the preceding 12 months. Of this total, 42 inches fell in October, 25 inches of which fell during a 24-hour period on October 14 and 15. In the northeastern part of the county levels were as much as 10 feet higher and in the remainder of eastern Broward County, about 5 feet higher than








REPORT OF INVESTIGATIONS NO. 65


1939 1945 1950 1955 1960 1965 f971


1963 1965


1963 1965 1971

Figure 32. Hydrographs of wells in the
County.


coastal intercanal areas of Broward










BUREAU OF GEOLOGY


5




2L-

1950
15

14



12





9

a
i
1950
8
7

6

5

4

3

2


1971


1963 65 1971 1963 65 1971

Figure 33. Hydrographs of wells in the interior intercanal areas of Broward
County.


55 60 65 1971


1959









REPORT OF INVESTIGATIONS NO. 65


on May 5, 1971 when low conditions prevailed (fig. 35). All coastal controls in canals were partly or completely open to release flood waters to the ocean. Pump station S-9, near the west end of South New River Canal, was pumping water westward into the conservation area, and pump station S-13 on the same canal near the coast, was pumping water eastward to the ocean. Water levels east of the Dixie well field rose sharply in response to the rainfall and remained at these high levels for several days, probably due to the low permeability of the surficial material which retarded the downward infiltration of rainfall. Additional canals which had been constructed north of the well field prevented


7 -
6
5
4
3
2

0

-2
-3
1960


1962 65


Figure 34. Hydrographs of wells in major well-field areas of Broward
County.







BUREAU OF GEOLOGY


flooding or a significant rise in water levels that normally would have resulted from the heavy rainfall. Minor flooding occurred in the Pompano Beach Deerfield Beach area where the rainfall was most intense. The canal network in existence at that time prevented a flood of major proportions.


Figure 35. Water-level contour map of eastern Broward County under
record low conditions, May 5, 1971.








REPORT OF INVESTIGATIONS NO. 65


Figure 36. Water-level contour map of eastern Broward County under
record high conditions, Nov. 1, 1965.







58 BUREAU OF GEOLOGY

The configuration of 'the water table during a period of near-average water levels (fig. 37) is similar both to that when levels are low and when they are high. The water-table gradient is generally to the south, except near the coast, and near the conservation areas. In the intercanal areas surface runoff and ground water generally flow south or southeast into the canals and then seaward as canal discharge. The sandy surficial materials of low permeability along the coastal* ridge north of Pompano Beach retard rapid movement of ground-water discharge thereby maintaining high water levels.


20 is, to' S. aoln'


24 r -


Figure 37. Water-level contour map of eastern Broward County under
near-average conditions, May 25-26, 1964.












REPORT OF INVESTIGATIONS NO. 65


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I I I I I I I I I I I i F M A M j J A 0 N D


Hydrographs of wells in the Pompano Beach well field and the Fort Lauderdale Dixie and Prospect well fields, 1965 and 1971.








BUREAU OF GEOLOGY


Annual fluctuations of water levels in the three largest well-fields for a low year (1971) and a high year (1965) are shown in figure 38. Water-level declines are greatest in the first 5 months of the year when recharge is minimal and discharges from the well fields are maximal. Water levels rise from June through October because of seasonal rainfall and consequent decreased pumping. The difference in water levels between the low period of the dry year and the high period of the wet year was as much as 14 feet.



sQ'3 II 0 09, 08 01 o, 05' 8004'


Figure 39. Water-level contour map of the Pompano Beach well field and
surrounding area during a period of low-water levels and peak
pumpage, May 5, 1971.







REPORT OF INVESTIGATIONS NO. 65


On May 5,. 1971 (fig. 39), the large discharge from the Pompano Beach well field had lowered the water level to 3 feet below mean sea level. Recharge to the well field was from the area of higher water levels to the west and from the Pompano Canal to the south. Water levels between the well field and the Intracoastal Waterway were near sea level.

In the Prospect well field, pumping during the dry season had lowered the water table by May 5, 1971 to more than 5 feet below mean sea level near the center of pumping and to mean sea level between the well field and the salty reach of Middle River Canal (fig. 40). Most of the recharge to the well field came from the controlled reach of the Cypress Creek Canal upstream of S-37A control and from areas of higher water levels to the west and northwest. During the


Figure 40. Water-level contour map of the Fort Lauderdale Prospect well
field and surrounding area during a period of low-water levels
and peak pumpage, May 5, 1971.




Figure 41. Water-levi
and sumo peak pum
13'


tap of the P1 contour Mield during a funding areland 1971. page, May 5,


ort Lauderdale Dixie well I eriod of low-water levels


I11 10"


PLANTATIONN
CAIIAL ANO OOITO
WAER LEVEL CO it OASHED WHEE EStI OATUm iS UEMA SEA CONTOUR ItRVA 0.








REPORT OF INVESTIGATIONS NO. 65


drought the center of pumping was shifted as far inland as possible to minimize the threat of sea water intrusion. Because the control on the Middle River Canal is too far inland to prevent further salt-water intrusion and to provide optimum recharge, a feeder canal was constructed to convey water from the controlled reach of the canal northward through a series of borrow pits into the well field area. The water then flows through a drainageway and salinity control into the tidal reach of Middle River Canal. The controlled feeder canal will provide a major source of recharge near the well field, and help retard sea-water intrusion into the aquifer.

During the drought of May 1971, withdrawals from the Dixie well field had lowered the water table as low as 2 feet below mean sea level in the southern part of the well field and 0.5 foot below mean sea level in the northern part (fig. 41). The well field received recharge from the Plantation Canal on the north and the Holloway Canal on the west. However, the location of the control to the west of the well field on the North New River Canal negates the -recharge effects of the canal. The proximity of the uncontrolled part of the canal to the well field poses a threat of salt-water intrusion into the aquifer because of the very low water levels between the canal and the well field. During the early part of the drought, only the wells in the northern part of the well field were pumped to maintain higher water levels between the North New River Canal and the well field. This shift also moved the center of pumping closer to the Plantation Canal which is a source of recharge.

By October 1971, levels in the county had recovered considerably because of seasonal rainfall and reduced withdrawals. However, figure 42 shows that water levels in the major well field areas and in much of the coastal area remained well below normal for October. Levels along the coastal ridge between Pompano Beach and Deerfield Beach were as much as 5 feet below the October average.

Figure 42 also shows refinements in the configurations of the water table resulting from the expansion of the data collection network and the construction of new canals. These new canals have altered the configuration of the water table considerably in the area between the two Fort Lauderdale well fields by lowering water levels to prevent flooding. Flow in the new canals north of the Dixie well field is controlled to regulate the amount of water entering the Plantation Canal (C-12).

Water levels in the triangular area east of Levee 35A and north of North New River Canal are controlled by pumping water from collector canals into the larger C-42 Canal that flows into North New River Canal. Flood-control facilities for the city of Plantation were developed in this manner during the late 1940's.







BUREAU OF GEOLOGY


Figure 42. Water-level contour map of eastern Broward County, October
19, 1971.


To keep pace with increased municipal water demands, well fields throughout Broward County have continued to increase withdrawals resulting in further lowering of water levels. To minimize the lowering of water levels, well fields have been expanded in size, or the facilities for recharge have been increased. The Prospect well field is an example of the use of both methods. When the Prospect well field began, 10 supply wells in the southeast part of the field had a capacity of about 10 mgd. By August 1957, the water table in the well field during the dry season declined to 2 feet below msl.








REPORT OF INVESTIGATIONS NO. 65


Between 1959 and 1960, 12 new supply wells were drilled, increasing the capacity to about 25 mgd, and the drainage pattern of the well field area was changed by the improvement of the Cypress Creek channel and its connection with the Pompano Canal. Control structures were installed on the bypass canal north and northeast of the well field. The expansion of the well field moved the center of pumpage to the west, away from the tidal reach of the Middle River Canal. The improvement of the Cypress Creek drainageway provided a source of recharge closer to the well field.

In 1965, Prospect Lake, about 1 mile west of the well field was incorporated into the municipal system as an auxiliary source of supply. Since 1967, several additional supply wells were drilled near the lake. The effects of heavy withdrawals during the 1970-71 drought are shown in figure 40; water levels were lowered to more than 5 feet below msl in the main well field and to more than 3 feet below msl in the lake area. A feeder canal, completed in 1971, conveys fresh water from the Middle River Canal into the southern part of the well field area and provides additional protection against salt-water intrusion from the uncontrolled reaches of the Middle River Canal.

The water-level contour maps show that the altitude of the water table can be controlled in most areas throughout the county, except during extreme floods or droughts. Abnormally high rainfall may cause flooding in some areas, whereas extended droughts may cause water levels to decline to a critical position in well field areas. However, with proper planning and management, deleterious effects from these extremes may be held to a minimun. The local water-management needs that are most obvious include an improved secondary canal network with backpumping facilities for flood control and water conservation during floods, and the seaward relocation of several critical salinity barriers for control of sea-water intrusion and aquifer replenishment during droughts.

WELL DEVELOPMENT

Wells can be drilled to almost any depth in the Biscayne aquifer throughout Broward County. Many small-diameter wells (2 inches or less) are hand-drilled in the surficial sands or shallow limestone to a depth of about 30 feet. If the well is bottomed in sand, it is finished with a well screen (sandpoint). Surging the well with a 2- inch pump will usually produce 40 to 60 gpm with a drawdown of water level of about 6 to 8 feet. If limestone or sandstone is within 30 feet of the land surface, the well can be finished by driving the casing to the top of the limestone and drilling a few feet of open hole into the limestone. The yield of wells finished in this manner may be as much as 100 gpm with a drawdown of 1 to 5 feet. Most wells for private domestic supply and lawn







BUREAU OF GEOLOGY


irrigation range in depth from 40 to 60 feet. Drilling wells to these depths insures an adequate supply of water when water levels decline regionally and also less contamination from the land surface.

Most wells 3 to 6 inches in diameter are drilled by jet percussion, cable tool, or rotary methods. Wells completed in unconsolidated material, are usually finished with screens or slotted well casing. However, most wells are drilled until a consolidated zone is reached, generally between 60-150 feet because the yields from these zones are higher than from unconsolidated zones. In the consolidated zones, wells are finished with 10 or 15 feet of open hole and yield as much as 1,000 gpm with about 3 to 6 feet of drawdown.

Large diameter wells (8 to 12 inches) are usually drilled in municipal well fields and on large farms. When these wells tap the lower limestones of the Biscayne aquifer near the coast, they generally yield more than 1,500 gpm with only 3 to 6 feet of drawdown. Some of the municipal wells are finished with as much as 40 feet of slotted casing surrounded by gravel packing to insure maximum yield and long-term use of the well.



HYDRAULIC PROPERTIES

The principal hydraulic properties of an aquifer are its capacities to transmit and store water, which are generally expressed as transmissivity (Theis, 1938, p. 892) and the storage coefficient. The most commonly used method for determining these properties is an aquifer test, whereby the lowering of water levels by pumping is related both to distance and to time.

Aquifer tests have been made near the coastal reach of the Snake Creek Canal (Leach & Sherwood, 1963), and along Levee 30 (Klein and Sherwood, 1961), in north Dade County, and in the Fort Lauderdale Dixie (Vorhis, 1948) and Prospect (Sherwood, 1959) well fields, and the Pompano Beach and Deerfield Beach well fields (Tarver, 1964).

Transmissivity and storage coefficient were computed from the Snake Creek Canal tests as 2.0 to 2.5 mgd per foot and 0.1 to 0.2, respectively, and the leakage coefficient (Hantush, 1956, p. 702) ranged from 20 to 30 gpd per square foot per foot of head differential. The magnitude of the leakage coefficient indicates that infiltration would occur readily from surface water sources such as the Snake Creek Canal. Underseepage tests made in a small area along Levee 30 near the inland end of Snake Creek Canal indicate a transmissivity of 3.6 mgd per foot. The aquifer in this area is composed chiefly of solution-riddled limestone which extends to a depth of about 55 feet below land surface.








REPORT OF INVESTIGATIONS NO. 65


An early aquifer test using supply wells in the Fort Lauderdale Dixie well field indicated a transmissivity of 1.2 mgd per foot. In the Prospect well field test, selected municipal supply wells were pumped and other supply wells were used for observation of the water level responses; transmissivity ranged from 2 to 3 mgd per foot. The apparent storage coefficient was approximately 0.015, and the leakage coefficient was about 1 gpd per square foot per foot of head differential.
Muncipal supply wells were also used for tests in the Pompano Beach and Deerfield Beach aquifer tests. In the Pompano Beach test, transmissivity and storage coefficients were 1.4 mgd per foot and 0.34, respectively. The leakage coefficient was not computed. At the Deerfield Beach test, transmissivity and storage coefficients were 0.4 mgd per foot and 0.0004, respectively. Geologic data indicates that the low values for the hydraulic characteristics in the Deerfield Beach test were due to the development of the supply wells in a relatively thin limestone bed in the upper part (80 feet) of the aquifer which is overlain by calcareous sands of low permeability. Additional wells, nearby, bottomed in a deeper (110 feet) and thicker limestone yield greater quantities of water with considerably less drawdown indicating higher values for the hydraulic characteristics. Thus it appears that the Deerfield Beach test is only representative of a small area, where the upper limestone aquifer is confined, while the aquifer in general is unconfined.

The differences in tranmissivity for the four tests indicates that the potential for development of the Biscayne aquifer generally decreases in a northerly direction in Broward County. This is due primarily to a decrease in the permeability of the consolidated section of the aquifer as both the porosity and interconnection of the pores spaces decrease with increased sand content in the limestone beds. The aquifer is thickest in the northeastern part of the county, but conversely, the transmissivity is the smallest.

Water-level and aquifer-test data indicate that the Biscayne aquifer exhibits different characteristics under static conditions (nonpumping) than under pumping conditions. Under static conditions, the water level in a shallow well will be at the same elevation as the water level in an adjacent deep well, suggesting that the entire aquifer is under unconfined conditions. However, when the deep (100-150 feet), highly permeable zones of the aquifer are pumped, water levels in deep wells as much as 1,000 feet away show an immediate rapid decline and the levels in shallow wells much closer to the pumping wells show no immediate effect. Levels in these shallow wells do show a long-term drawdown of several feet. Thus, in aquifer tests of short duration (less than 24 hours) the zone in which the supply wells are developed reacts as a confined aquifer overlain and partly confined by a leaky roof of less permeable beds.







BUREAU OF GEOLOGY


The high leakage and storage coefficients in the test at Snake Creek Canal indicates that the overlying semiconfining beds are more permeable than are similar beds in central and north Broward County and that the aquifer in south Broward responds to pumping much more as nonartesian aquifer than it does in other parts of the county.

FLORIDAN AQUIFER

The Floridan aquifer is a thick section of carbonate and evaporite rocks underlying all of Florida and parts of Georgia and Alabama. In southeastern Florida the aquifer underlies a thick section of impermeable marl and clay at depths below 900 feet and extends to depths of more than 3000 feet. It is composed primarily of a system of limestones of varying permeability which dip eastward and southward and are thought to intersect the ocean bottom several miles offshore along the Continental Slope.

The aquifer is confined except in the recharge area where the overlying confining materials are very thin or absent.

In Broward County, water in wells that tap the Floridan aquifer will rise almost 40 feet above msl. Flows range from 75 gpm to over 2,000 gpm and average about 750 gpm (Parker, 1955, p. 191). The water is highly mineralized, containing more than 1,500 mg/l (milligrams per liter) of chloride, 3,500 mg/I dissolved solids, and is sulfurous, hard, and corrosive. These characteristics greatly limit the use of the water from this aquifer for most purposes. Nevertheless, study is being directed toward determining the feasibility of using the aquifer for fresh-water storage and as a source of water for desalination in the upper less mineralized zones. One well near Lake Okeechobee is currently disposing of industrial wastes in the highly permeable "boulder zone" of the Floridan aquifer with apparent success. A similar well in Miami is used as a disposal well for treated sewage effluent. Current studies are designed to more accurately define the zonation and hydraulic characteristics of the Floridan aquifer in the hydrologic system of southeastern Florida.

WATER QUALITY

The chemical or physical quality of water generally is as important for most uses as its availability. Rainfall, the original source of water supplies, contains fewer impurities than water in most other parts of the hydrologic cycle. It contains only minute quantities of dust, dissolved gases, and wind-blown salt from the atmosphere. When rain strikes the ground, it comes into contact with many soluble materials and, aided by carbon dioxide absorbed from the air and soil, it begins to dissolve and pick up a wide variety of chemical and organic








REPORT OF INVESTIGATIONS NO. 65


constituents. The type and amount of dissolved matter in natural waters, depends on the materials contacted and the length of time involved in the movement of water through the rocks and soil and down the streams. Domestic and industrial wastes as well as sea water are also sources of mineral or biological contamination of streams and ground water.

NATURAL CONSTITUENTS

The chemical quality of the water in the interrelated surface and ground-water flow system in Broward County is generally good. The source of the water in the system is local rainfall or rainwater conveyed into the area by the regional canal network. The water often shows a mixture of ground-and surfice-water characteristics because of the free interchange of water between the canals and the permeable limestone of the Biscayne aquifer.

GROUND WATER

The chemical characteristics of ground water in the county are influenced chiefly by soluble limestones and calcareous sand in the Biscayne aquifer. The water is generally hard, calcium bicarbonate in type with varying quantities of iron in most areas. Mineralization generally increases inland and with depth-in the aquifer. Water of the best quality occurs in coastal areas where the aquifer has been flushed by the infiltration of rainfall. This is especially true along a low coastal ridge in the Pompano area where a thick section of permeable sand occurs in the upper part of the aquifer.

The chemical characteristics of water at different depths throughout the county were determined by the analysis of water samples from existing wells at known depths and from samples collected at different depths during the drilling of test wells. Table 3, adapted from Grantham and Sherwood (1968), summarizes the results of analyses of samples from the wells shown on figure 43.

Dissolved solids, hardness; and iron in ground water vary with depth in eastern Broward County as shown on the maps in figure 44 (adapted from Grantham and Sherwood, 1968). The relatively low dissolved solids and hardness in water in the Ft. Lauderdale area indicates the effects of flushing by the circulation of ground water caused by drainage to the canals and recharge by rainfall. The consistently high concentrations of dissolved solids at depths below 200 feet indicates -that there is much less circulation at those depths and thus more time for the water to dissolve minerals from the aquifer materials. The similarity between dissolved solids and hardness illustrates that calcium and bicarbonate dissolved from the limestone are the major constituents of natural waters in the county. The ground water of Broward County ranges from hard to







BUREAU OF GEOLOGY


very hard and is hardest in the northern part of the county. The iron content of ground water varies areally and with depth in the aquifer. As seen on the map, the iron concentration increases to the south and west and with depth. Also, it is apparent that the iron content in water throughout most of the county is higher than the concentration (0.5 mg/I) required to stain plumbing fixtures.


Figure 43. Location of water sampling stations shown in tables 3 and 4.












REPORT OF INVESTIGATIONS NO. 65


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Table 3, Chemical analyses of ground water in liroward County (adapted from Grantham and Sherwood, 1968, table 1). continued 114 (results In milligrams per liter except p11, specific conductance, temperature and color)


-.. .. ..-.-r-,, - - - lisoived lIardneus
Dale Depth onduc- Tern- hat Po- Cu- bollds
Well of o t per. Silica Cal. no- Sodium cap Dic- bon. Sulfate Chlo- 1 lou. Ni- Iron Non. Co1. number colIlC. %vu1 (micro- PH1 isure (SI02) cium slum (NA) dum b Mnate age (S04) ride ride Irate (Fe) Resdue Cal- Cli, cas. or
don (1l) mhos (T) (C ()1g) (k) (UC0j) (C0) ICI) (F1) (NO3) at cu- magna. bon.
2S C) 180"C Ialed slum ate
G1236 03-29-64 187 SO0 7.9 75 13. 8S 23. 240, 10. 316 0 10. 391 0.2 1.3 0.22 930 308 49 10
G-1236 03-31-64 204 3480 8.0 14. 78 79. 567. 24. 376 0 54. 980 .4 2.0 4,4 2200 1980 520 212 20
S-1499 04-06-62 115 438 7.7 78 9,3 78 5.0 13. .6 240 0 10. 18 .0 .0 2.2 272 252 215 18 55
S-14S6 06-18.63 126 437 7.7 9.6 84 3.8 11. .0 260 0 6.9 19 .4 .0 296 263 225 12 45
S-1500 04-05-62 65 434 7.8 75 9.1 $6 12. 22. 2.3 218 0 .0 32 .0 .2 '.52 240 241 189 10 20
S-150l 04.02-62 58 559 7.5 76 7.7 86 5.0 28. .7 244 0 17. 45 .0 3.9 1.6, 376 313 235 35 80
G-617 09.30-64 28 490 8.1 78 2.2 98 3.8 7.0 2.0 320 0 .0 10 .4 4.3 - 286 260 0 45
S-1502 04,06-62 136 443 7.6 73 8.6 83 2.2 9.0 0.5 246 0 8.4 15 .1 .3 1.34 254 248 216 14 1s
G.221 12-03-41 124 436 77 84 1.7 A9.5 252 12. 13 .0 - 245 217 5
G-221 12-05-41 147 484 77 80 22. All. 250 2.0 18 .2 - 257 209 5
0221 1206-41 171 S00 76 71 2.6 A]3. 226 2.1 21 .- .2 - 221 188 5
G-221 12-1741 228 960 77 82 19. A98. 332 2.7 157 .0 - 522 283 5
G-221 12.1841 263 3620 77 69 57. A572. 342 2.3 970 - - 1840 407 $
G-221 12-23-41 314 8940 76 110 139. A1650. 300 333. 2720 - - 5100 846 5
G-1234 05.28-64 58 780 810 15. 89 36. 44. 1.7 376 0 6.4 76 .4 .2 .45 494 454 368 60 50
S-1504 04-05-62 100 489 7.9 73 9.5 94 2.6 12. .5 284 0 4.8 18 .0 .5 3.0 304 282 245 12 45
S-1505 04-0.62 155 636 7.8 75 9.7 120 5.0 18. .6 330 0 24. 31 .0 1.0 3.0 396 372 320 50 25
S-1503 07-02-63 56 520 8.0 7.1 84 5.0 26. .7 260 0 4.4 43 .3 .2 1.3 339 299 230 17 50
G-1233 02"13"63 23 505 8.0 7.0 78 14. 19. .5 234 0 16. 44 .5 .0 1.0 320 294 254 62 40
Co-1233 021463 113 510 7.9 8.1 59 1.2 22. .5 164 0 24. 27 .2 .0 .15 223 152 18 30
0"1233 0217-63 185 1050 8.0 13. 69 9.2 132. 4.4 192 0 is. 240 .2 .7 .41 574 210 52 15
G-1233 02-1863 208 1330 7.9 13. 64 57. 180. 5.4 300 0 12. 295 .4 .8 .20 774 776 395 199 30
S-1506 04-22-64 45 840 7.7 77 20. 98 19. 66. 2.2 388 0 2.8 100 .5 .0 1.80 501 321 3 70
G-220 10-23.41 37 580 73 94 9.4 A18. 325 6.6 28 .3 - 316 273 160
G-220 10-25.41 62 594 73 96 9.4 A18. 326 5.3 31 .3 - 321 278 120
G-220 10-2841 133 2180 75 70 34. A351. 558 43. 408 - - 1181 314 20
G-220 10-30-41 190 2380 76 56 45. A407. 672 31. 445 - - 1315 325 20
S-1507 04.0.62 74 399 7.7 76 11. 76 1.3 8.0 .5 228 0 3.2 14 .0 A 1.8 242 226 195 8 20
G-1231 01-07-64 23 423 S.1 9.2 83 4.1 8.9 .2 256 0 2.8 16 .2 '0 1.9. 272 250 224 14 50
0-1231 01-08-64 56 642 7.4 78 10. 83 2.2 58. 1.4 282 0 25. 63 .2 .0 1.40 382 216 0 45
G-1231 01.09-64 85 459 8.3 78 8.2 75 1.7 17. .5 204 4 13. 32 .2 .0 .22 252 194 27 25
G-1231 01-15-64 167 1120 7.7 9.4 94 2.3 116. .8 126 0 4.8 280 .2 1.2 1.4 571 244 140 8
C-1231 01-16.64 186 4850 7.8 10. 128 125. 750. 2.0 230 0 24.. 1580 .2 1.8 3.1 3230 2730 835 646 20
S-1509 04.05-62 79 384 7.7 77 7.9 72 3.8 6.4 .7 220 0 2.8 12 .0 1.0 0.92 228 215 195 14 15
S-1508 04.06-62 80 488 8.4 7.8 98 1.3 13. .6 278 6 3.6 19 .0 1.1 326 287 250 12 120
G-1232 04-2264 84 251 8. 12. 44 3.9 6.6 .6 146 0 .0 10 .4 .1 158 150 126 22 20


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REPORT OF INVESTIGATIONS NO. 65


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BUREAU OF GEOLOGY


F-ire 44. Variation in dissolved solids, hardness and iron in ground water
of eastern Broward County, 1964 (adapted from Grantham and
Sherwood, 1968).








REPORT OF INVESTIGATIONS NO. 65


Water in the Floridan aquifer is highly mineralized, has hydrogen sulfide gas in solution, and thus of slight value for normal use; however, the large quantities of water available and the excellent storage capacity of the aquifer seem to warrant much further investigation of potential uses. The aquifer yields artesian water whose chloride content ranges from about 1,500 mg/l in the upper producing zones to 18,000 mg/l sea-water concentrations near the bottom. The water is corrosive to metal. However, because wells in the Floridan aquifer flow freely and the water temperature is constant, the salty water has been used for industrial cooling and air-conditioning 'as well as for swimming pools, flushing wastes, and for irrigation of golf courses. Although it may not be feasible at present to use this water for more purposes 'than those just stated it has an excellent potential for use in future years when maximum growth is attained and all fresh-water resources are fully managed in the county.

In the Pompano Beach area a utility company uses two 18-inch wells more than 1,000 feet deep for effluent disposal. About 500,000 gallons of treated sewage are pumped into these wells each day against a head of about 30 feet. This same technique is being used or planned for use in other sections of the State to dispose of municipal and industrial wastes to prevent pollution of the streams and shallow ground water.

Because of the excellent storage capacity of the aquifer, especially the cavernous zones (boulder zone) below the 2,500 foot depth, the Floridan aquifer may have excellent potential for storing fresh water for retrieval. Depending upon the confining characteristics of intervening beds in the aquifer it is conceivable that fresh water could be safely stored in the upper low chloride zones and waste effluent injected into the lower cavernous zones. Safe use of the aquifer for this purpose would depend on detailed knowledge of its hydraulic properties.

SURFACE WATER

The chemical quality of the water in the canal system varies widely with extremes in discharge caused by rainfall and operation of water-control structures. During high discharge most of the water is surface runoff from inland areas and is highly colored but only slightly mineralized. During low discharge much of the water is derived from the more mineralized ground-water inflow and the amount of dissolved solids increases. Upstream from the salinity controls, the water in the canals is fresh and is therefore a major source of water; downstream, the water is generally salty except during periods of high discharge.

Water in the controlled canals is not used directly for municipal or domestic supplies, but infiltration from the canals supplies replenishment to







BUREAU OF GEOLOGY


many municipal and private well fields. Thus, the mineral content of the canal water is of great importance.


The quality of surface waters in most areas in Broward County is within the limits of the Florida State Water Standards; however, surface water is much more variable in mineral content than ground water, and therefore, it is more difficult to treat (Grantham and Sherwood, 1968, p. 41).


The analyses given in table 4 represent the extremes in chemical composition of water in the canals shown in figure 43 for the period of record. More complete data on surface-water quality are given by Grantham and Sherwood (1968).


Most of the surface waters sampled during this investigation are alkaline, ranging in pH from 6.9 to 8A. When slightly acid rain water comes in contact with limestone which underlies the area, solution takes place which causes the ground water to become slightly alkaline. Therefore, during dry periods the alkalinity of the canal water increases because the contribution to the canal by ground water increases. The total mineral content of the water along controlled reaches of canals usually ranges from 150 to 600 mg/I.


The canal waters range in color from 10. to 160 standard platinum-cobalt units and therefore are usually above the level (15 units) suggested by the U. S. Public Health Service (1962) for drinking water. This does not represent a major problem at present, because the principal use of water from the canals is for crop irrigation. When canal water infiltrates to the water table, most of the color is filtered out as the water moves through the aquifer.



CONTAMINATION OF WATER RESOURCES

Contamination is the chief threat to Broward County's present and future water supplies. Because this problem is a direct result of man's activities it grows in pace with the mushrooming population. Also, the possible effects of contamination are greatly increased by the free interchange of water between the surface-flow system and the aquifer. The two major sources of contamination in Broward County are sea water and man-made wastes.








Table 4. Selected chemical analyses of surface water in Broward County (extremes in chemical content)


0 Dissolved Hardness 40
Solids at CaCO3 ;
G)0 19
Mean Cal- Non
Date Dis- co Magne- Sod- Potas- n Sul- Chlo- Fluo- Residue Cal- cium, car- o
of' charge Iron sium lum sium fate ride ride at cul- ,magne- bon- '
Collection (cfs) C' (Fe) cj, (Mg) (Na) (K) __ (S04) (CI) (F) z 180"C ated sium ate m pH 0

2-2813. HILLSBORO CANAL ABOVE S-39, NEAR DEERFIELD BEACH June 15, 1962 0. 15.0 0.03 84 27. 225 5.8 380 64. 270 1.4 879 320 9 1540 7.8 90 Jan. 3, 1961 113. 1.3 .08 18 4.1 21 2.0 66 7.2 28 1.7 116 62 8 217 7.4 110 2-2815. HILLSBORO CANAL ABOVE CONTROL, AT DEERFIELD BEACH Dec. 4, 1962 74. 11.. .12 58 21. 107 4.8 264 28. 152 0.8 .2 610 513 231 14 900 8.0 160
May 18, 1967 20. 5.6 .03 58 6.1 28 1.3 194 11. 45 .4 .6 283 253 170 12 510 7.4 50 2-2815. 1E. HILLSBORO CANAL BELOW CONTROL, NEAR DEERFIELD BEACH May 20, 1964 172. 8.0 .03 92 7.4' 65 2.3 268 26. 102 .5 .0 492 260 40 1270 7.8 70 Oct. 8, 1963 244. 6.9 .06 86 4.7 40 3.9 252 21. 61 .4 .2 356 234 28 600 7.8 80 2-2817. POMPANO CANAL BELOW S-38, NEAR POMPANO BEACH May 26, 1965 93. 21. .01 70 28. 155 6.3 310 36. 232 .9 .5 703 288 34 1300 7.7 100 April 22, 1964 -9. 3.4 .03 31 7.9 50 1.7 134 4.5 61 .4 .1 226 110 0 401 7.2 50 2-2820. POMPANO CANAL ABOVE CONTROL, AT POMPANO BEACH July 17, 1963 57. 8.9 .05 86 7.7 57 2.6 276 20. 81 .5 .1 442 400 246 20 712 7.5 70 Oct. 16, 1965 100. 6.6 .03 57 2.1 12 1.4 168 8.8 19 .2 .6 191 150 13 338 7.7 20









Table 4. Continued Selected chemical analyses of surface water in Broward County (extremes In chemical content)


Dissolved Hardness .
Solids at CaCO3 ,

Mea "" ,Cal- Non Mean
Date Dis- .2 Magne- Sod- Potas- .0 Sul- Ct o- Flu Residue Cal- cium, car- I of charge Iron sium Jum sium 5 fate ride ride I at cul- magn bon- "
Collection (cfs) (Fe) (Mg) (Na) (K) m (SO4) (Cl) (F) 180C ated sium ate pH

2-2820.1. POMPANO CANAL BELOW CONTROL, AT POMPANO BEACH Feb. 22, 1965 0.3 3.0 .02 292 774. 6570 242. 201 1580 11500 1.0 2.8 21100 3910 3740 31100 7.2 25 July 17, 1963 57. 8.6 .02 86 7.7 60 2.7 276 22 83 .6 .2 448 407 246 20 702 7.5 65 2-2821. CYPRESS CREEK CANAL ABOVE S-37A, NEAR POMPANO BEACH May 20, 1964 63. 4.8 .05 137 187.' 1520 56. 252 382 2740 .5 1.0 5620 1110 904 8420 7.7 60 Oct 16,1965 1,100;. 5.6 .03 65 4.3 24 2.7 188 20 36 .3 2.1 253 180 26 449 7.4 30 2-2821.1E. CYPRESS CREEK CANAL BELOW S-37A, NEAR POMPANO BEACH Apr. 21, 1964 0. .7 .02 320 893. 7230 310. 189 1780 13200 1.1 .1 26000 4470 4320 35800 7.2 45 Oct. 28, 1964 554. 6.9 .09 88 37. 278 12. 236 80 490 .2 2.0 1110 370 176 1980 7.5 80 2-2827. MIDDLE RIVER CANAL ABOVE S-36, NEAR FORT LAUDERDALE Apr. 3, 1963 0. 6.9 .02 152 117. 1000 48. 296 256 1800 .4 6.3 3710 3530 860 618 5620 7.3 50
Oct. 18, 1964 122. 2.2 .14 90 1.8 13 1.7 240 19 23 .3 .0 269 232 36 459 7.7 70 2-2827.OE. MIDDLE RIVER CANAL BELOW S-36, NEAR FORT LAUDERDALE May 8, 1967 0. 1.5 .12 257 577.0 4920 206.0 208 1220 8890 .8 26. 6200 3020 2850 28,000 7.3 30 Oct. 28, 1964 124. 7.9 .10 104 2.1 16 2.0 290 22 26 1 .2 .2 309 268 30 540 7.7 90 2-2827.5E. MIDDLE RIVER CANAL NEAR FORT LAUDERDALE April5, 1963 4.8 .01 184 282., 2440 105. 255 598 4290 .3 20. 8480 8050 1620 1410 11900 7.5 60 Oct. 8,1963 6.7 .09 91 2.7 12 2.1 248 24 20 .2 .1 296 238 35 477 7.5 80


0"


0
t"
0
C)





Table 4. Continued Selected chemical analyses of surface water in Broward County (extremes in chemical content)

0
Dissolved Hardness .C14
M iM_ Solids at CaCO3

Cal- Non
Date Dis- Magne- Sod- Potas-. Sul- Chlo- Fluo- Residue Cal- c2um carof charge .2 Iron sium ium sium 0 fate ride ride a b 0 C c (cs ft (F) (ride at cu Magne bon-ate p I Collection Wcs) n I(Fe) u M (Na) (K) S4 C)(F) 180"C atd sim at pH U
!M)0 0 (I C td su t


2-2830.1E.
May 8, 1967 32. 9.8 .00 Oct. 8, 1963 64. 7.8 .05 2-2832. !
Apr. 1, 1968 0. 13. .05 Apr. 11, 1966 0. 8.2 .00 2-2846.9E.
Apr.. 3, 1963 397. 8.3 .04 Apr. 22, 1964 399. 6.6 .03


May 4, 1967 Apr. 22,1964


Apr. 5, 1962 Sept. 11, 1961


May 26,1965 Oct. 30, 1964


PLANTATION ROAD CANAL 95 62. 552 25. 179 90 2.8 17 1.9 255


PLANTATION 51 3.7 79 2.3


BELOW 139 18


ROAD CANAL ABOVE 59 7.6 184 38. 22 3.4 222 16.


NORTH NEW RIVER CANAL 84 27. 57 2.5 340 35 9.8 59 1.4 153


2-2847. NORTH NEW RIVER CANAL 397. 11. .02 56 22. 104 43. 294 399. 7.0 .04 48 12. 51 1.5 200


2-2848. NORTH
5.2 .02 78 4.0 .06 64

2-2850. NORTH
0. 5.2 .05 50 202. 8.8 .06 82


NEW RIVER
9.6 61 5.5 20 qEW RIVER C 18. 78 7.7 29


I


CANAL AT
2.5 256 .6 H196


ABOVE 27. 25. ELOW S 24. 7.6


S-33, NEAR FORT LAUDERDALE 960 .5 19. 1960 493 25 .3 .1 296 236


S-33, NEAR FORT
82 .5 .8
30 .4 12.


LAUDERDALE 373 378 142
282 207


S-34, NEAR FORT LAUDERDALE 95 .5 .5 504 496 320 74 .4 .1 286 128


-34, NEAR 145 .8 76 .4


CANAL C-42, 18. 94 12. 32


ANAL ABOVE CONTROL
4.1 214 40. 110 1.5 260 16. 46


FORT .4
.1


LAUDERDALE 590 514 232 312 170


NEAR FORT LAUDERDALE
1.6 396 234 .3 229 182


NEAR FORT .5 5.0 .4 1.8


LAUDERDALE
416 199
321 236


346 27


3750 7.0 70 500 7.2 70


0 700 7.4 80 25 476 7.4 50


42 960 7.5 80 2 472 7.3 50


0 955 7.7 70 6 551 7.4 50


24 720 8.1 60 22 410 7.9 70


24 1050 7.9 50 23 552 7.5 80







Table 4. Continued Selected chemical analyses of surface water in Broward County (extremes In chemical content)


Dissolved Hardness
,= ,, Solids At CaC03 .U

Mean : Cal- Non
Date Dis- .9 Magne- Sod- Potas- .8 Sul- Chlo- Fluo 2 Residue Cal- cium, cur- 2
of charge .iron slum i slum fate ride ride at cul- pHagn
Collection (cfs) in (Fe) u. (Mg) (Na) (K) (S04) (CI) (F) 180"C ated sium ate pH

2-2851.OE. NORTH NEW RIVER CANAL AT U.S. HWY 441 NEAR FORT LAUDERDALE May 12, 1965 0.6 3.9 .00 177 314.0 2640 9.4 199 661. 4630 1.4 4.3 8540 1730 1570 14100 7.4 50 Oct. 30,1964 202. 7.2 .07 86 7.2 29 1.5 264 18. 42 .3 1.2 322 244 28 553 7.5 80
2-2853-99. SOUTH NEW RIVER CANAL ABOVE S-9, NEAR DAVIE Jan. 15,1964 0. 17. .04 142 43.' 60 4.0 480 107. 125 1.0 3.2 738 510 116 1200 7.7 120 Apr. 3, 1963 0. 7.6 .03 94 7.2 38 1.3 316 12. 50 .4 1.1 396 368 264 5 612 7.3 90 2-2854. SOUTH NEW RIVER CANAL BELOW S-9, NEAR DAVIE May 26, 1965 0. 12. .02 93 15. 60 1.5 332 9.2 91 .5 .4 447 292 20 820 7.8 65 Sept. 1, 1964 459. 9.6 .07 90 6.2 32 2.0 280 14. 46 .3 .4 380 250 20 583 7.4 80 2-2860.5 SOUTH NEW RIVER CANAL AT S-13A, NEAR DAVIE Apr. 22, 1964 8.9 .02 93 16. 56 1.4 343 15. 77 1.1 296 16 738 8.2 80 June 6, 1960 482. 6.8 .05 62 6.2 20 5.1 196 18. 35 .4 251 180 20 449 8.1 120

2-2861. SOUTH NEW RIVER CANAL ABOVE S-13, NEAR DAVIE Dec. 14, 1961 15. 7.0 .06 104 63. 530 2.0 288 128 942 .3 1.3 1938 518 282 3420 7.8 70 Oct. 30, 1964 319. 6.9 .10 86 6.2 18 1.9 244 21. 29 .3 2.6 294 240 40 490 7.5 110 2-2861.5 HOLLYWOOD CANAL AT DANIA
2-2861.1E SOUTH NEW RIVER CANAL BELOW S-13, NEAR DAVIE May 21, 1965 .8 .00 391 1090.' 8300 315. 180 137. 16500 .7 17. 26.800 5460 5310 46000 7.2 10 Oct. 8, 1963 6.1 .06 116 58.v 470 21. 284 132. 840 .3 .8 1980 530 298 3180 7.7 60






Table 4. Continued Selected chemical analyses of surface water in Broward County (extremes in chemical content)

0A
Dissolved Hardness -a (4 Solids at CaCO3 ..
0 : 0 Mean w Cal-N
Date Dis- j Magne- Sod- Potas- Sul- Chlo- Flu Residue Cal- cium, car- .
o of char .--Iron slum ium sium fate ride ride at ci- hnagns b- U
Collection (cs5 (F U (Mg) (Na) (K) m (S04) (CI) (F) p 1800C ated sum ate

2-2861.8. SNAKE CREEK CANAL ABOVE S-30, NEAR HIALEAH May 8, 1967 277. 4.4 .02 80 11. 59 1.2 300 .0 91 .3 .4 441 396 246 0 760 7.7 50 Oct. 4, 1963 0. 7.0 .04 62 8.1 23 1.4 205 6.6 32 .7 .1 244 188 20 418 7.8 60 2-2861.8E. SNAKE CREEK CANAL BELOW S-30, NEAR HIALEAH May 26, 1965 120. 5.8 .00 94 6.2 53 .9 296 6.0 88 .5 .2 401 260 18 710 7.7 60 Oct. 9, 1963 0. 7.1 .05 70 6.7 25 1.4 232 4.8 34 .4 .5 280 202 12 462 7.8 70 2-2862. SNAKE CREEK CANAL AT N. W. 67th AVENUE, NEAR HIALEAH May 5, 1967 112. 5.2 .02 80 10. 51 1.1 290 .0 87 .3 .3 421 379 242 4 738 7.8 50 Apr. 3, 1963 81. 4.8 .01 82 7.7 34 1.0 278 9.6 46 .4 .3 346 323 236 8 546 7.5 60







BUREAU OF GEOLOGY


SEA-WATER INTRUSION

Sea-water intrusion began early in the century with the construction of deep drainage canals inland from the sea. These canals not only permitted sea water to flow far inland during periods of low discharge, but during dry periods they also lowered the water table below the level required to prevent the movement of sea water into the aquifer. The desirable aspects of these developments were clearly apparent; the undesirable aspects of salt intrusion were not detected until some of the fresh-water supplies were contaminated.Sea water is slightly heavier than fresh water because it contains more dissolved solids. A 41-foot column of fresh water is required to balance a 40-foot column of sea water. In a coastal aquifer, therefore, each foot of fresh water above sea level would indicate 40 feet of fresh water below sea level. Thus, sea water moves inland unless fresh-water levels are appreciably higher than sea level. In coastal streams and in porous subsurface materials, there is a constant balancing between the two. If fresh-water levels are high, sea water is held near the coast; if fresh-water levels are low, sea water moves up the tidal streams and inland in the aouifer beneath the fresh Prnund water.

The salt-water body in the aquifer (fig. 45) is wedge shaped, thickest at the coast and thinning inland where it underlies fresh ground water at depths of 160 to 200 feet (Grantham and Sherwood 1968, p. 36). The greatest inland penetration is in the vicinity of the greatest concentration of tidal canals. The configuration of the salt front also shows that intrusion may be effectively controlled by the construction of salinity control structures in primary canals. These controls halt the upstream movement of sea water and hold fresh-water heads high to prevent intrusion into the aquifer. Where control structures have been located near the coast, as in Snake Creek Canal, sea-water intrusion has been slight, whereas controls located inland, as in North and South New River Canals and Middle River Canal, permit further intrusion during droughts.


Salt water in the tidal reaches of the canals moves either seaward or inland, depending on the amount of fresh-water discharge. During low flow the sea water extends inland to the salinity structures in all canals; during periods of high discharge it is forced far downstream (g46). For example, a discharge of 50 to 75 cfs for Middle River and North New River Canals generally holds the sea water downstream from the sampling points (fig. 47). In contrast, the chloride content of Hollywood Canal is generally high because the canal drains a small area and discharge is low. Effective salinity control in this canal would require both a control structure and an additional source of fresh water to maintain high fresh-water levels upstream of the structure.








REPORT OF INVESTIGATIONS NO. 65


The position of the salt front in the aquifer is controlled chiefly by the height of fresh water levels above sea level. As seen by comparing the record low water-level contour map May 5, 1971 (fig.",35) and the map showing sea-water intrusion in 1970 (fig. 45) the configuration of the salt front and the water table are similar. It is also noted that the salt front has stabilized far seaward of the theoretical position based on a 41 to 40 ratio. Salinity studies in the Biscayne aquifer near Miami (Kohout and Klein, 1967) have shown that this seaward displacement is caused chiefly by the effects of short periods of high water levels caused by frequent pulses of heavy rainfall. In effect the salt front in the aquifer


Figure 45. Extent of sea-water intrusion 1970.





IoIJ Ao pus 41.q jo spo.ad li.znp ~mwznts lozuoo .~muo ;v ,01M jo :u41uoo op!.oPD


"gt amS.inj


CI4LCMIDI









REPORT OF INVESTIGATIONS NO. 65


85

BOCA RATON

DEERFIELD
BEACH


30 POMPANO





LAUDERDALE

DANIA
HOLLYWOOD S HALL ANDALE 930 4
1'rMILES


Figure 47. Discharge and chloride content of water from tidal reaches of
selected canals (see figure 43 for locations)







BUREAU OF GEOLOGY


moves inland slowly during long periods of low water levels and is forced, seaward rapidly during short periods of high water levels.

Sea-water intrusion has been a long standing threat to well fields in coastal areas because large-scale withdrawals lower local fresh-water levels in the aquifer and permit intrusion. The most serious cases of intrusion into well field areas have involved the movement of salty water into the aquifer from a tidal canal as in the Middle River Prospect well field area and the Hollywood Canal Dania well field area. In the area of heavy pumping, where ground-water flow is toward the well field, the combined effects of the canal and the pumping causes sea water to move into the aquifer from an uncontrolled canal as sketched in figure 48A. In contrast a controlled canal can provide a perennial source of fresh water to replenish the well field and to prevent intrusion by bringing in additional water from outside the area (fig.-48B).
The construction of salinity controls or fresh-water feeder canals as corrective measures has been extremely effective in critical areas. Such efforts are best illustrated in the area of the Fort Lauderdale Prospect well field under different water-control conditions in 1956 and 1961 (fig. 44). In 1956 pumpage was relatively small but water levels east and southeast of the well field were low 'Ind intrusion was occurring along the Middle River Canal (C-13) and Cypress Creek Canal (fig. 49A). During 1957-60 the capacity of the well field was increased to more than 25 mgd and the Cypress Creek Canal was extended inland to connect with the Pompano Canal with salinity control structures at Dixie Highway northeast of the well fieldand-5 miles- upstream.nQar the junction of the two canals. Predicted andsmeasured water levels resulting from the new pumping and water-control conditions are shown in figure 49B. The higher water level shown in the Cypress Creek Canal area indicated the beneficial effects of the new canal and controls. However, the intrusion from the Middle River Canal continued and salt water from the northernmost finger canal actually reached the southernmost wells during 1963 (fig. 50A).

The movement of salt water up this finger canal was halted by a temporary control structure constructed near its junction with Middle River Canal by the Broward Water Resources Department. In 1969 this agency began construction of a feeder canal (fig. SOB) to convey fresh water from the controlled reach of Middle River Canal into the finger canal for ground-water recharge in the area of the well field. In May 1971, when rainfall was low and pumpage high, after completion of the canal, 15 to 20 cfs were flowing from the canal into the aquifer and water levels in some reaches were as much as 4 feet higher than in May 1970. Thus, the canal constitutes a major barrier to further intrusion from the Middle River system to the south. The safe withdrawal of more than 60 mgd from the well field during drought periods indicates the effectiveness of overall salinity control measures in this area.









REPORT OF INVESTIGATIONS NO. 65


An uncontrolled canal
that extends lito an area
r 1--vy pumpage can convoy
salt water inland to contaminate
fresh water supplies.
















In contrast a controlled canal can provide a perennial source of
fresh water to prevent sea
water intrusion and to replenish
the well field by bringing in fresh .water from outside the area.


Figure 48. Effects of controlled and uncontrolled coastal canals on
sea-water intrusion.
























14 A..... C4 C



C.
0
.4 0 .00.,
0



RjI ONTOU. 4.
EDTOR WATER-LEVEL CONTOUR, IN O~ MSL % FEET REFERRED TO MSL CONTROL FORT CANAL MNIONLE U PRTA MILE PADR IML A~DL 'rernents Sy field measuremnenls A-August 7,1956 B-- Morch 23,1961

Figure 49. Water-level contour maps of the Prospect well field area Aug. 6;
1956 and March 23, 1961 determined by analog plotter and
model and by field measurements.









REPORT OF INVESTIGATIONS NO. 65


(a) Extent of sea-water intrusion

during 1963.


(b) Feeder canal and control constructed to convey fresh water
from Middle River Canal into the
well-field area for aquifer replenishment and the control of
sea-water intrusion.


Figure 50. Salinity control measures in the Middle River Canal Prospect
well field area.








BUREAU OF GEOLOGY


CONTAMINATION RELATED TO MAN'S ACTIVITIES

Water quality data indicate that the greatest potential threats to the water resources of Broward County are the contaminants related to man's urban, industrial, and agricultural activities -- especially to the disposal of massive quantities of liquid and solid wastes. Although the levels of contaminants are generally low the threats are greatly accented by the stress of a rapidly expanding population, a controlled canal system which limits the flushing of wastes and the susceptibility of the permeable shallow aquifer to the introduction of contaminants. However, pollution control efforts are intensifying and planned improvements in the treatment and disposal of urban waste are designed to alleviate the more serious sources of contamination. The Broward County Air and Water Pollution Control Board was established in 1969 and a master plan for countywide treatment and disposal of sewage is being implemented by the Broward County Utilities Department.

Contaminants which affect water resources have been categorized in eight general types (Federal Water Quality Administration, 1969): sewage and other oxygen-demanding wastes, disease-causing agents, plant nutrients, synthetic organic chemicals, inorganic chemicals and other mineral substances, sediment, radioactive substances, and heat. Varying degrees of contamination by all categories except radioactive substances occur in the Broward County canal system. Common contaminants in Broward County are:
Oxygen-demanding wastes -- Organic wastes including human sewage and wastes
of plant and animal origin from food processing, paper production, and other manufacturing processes. These wastes are usually destroyed by bacteria if sufficient oxygen is present in the water, however, excessive use of oxygen by decomposition of wastes increases the mortality of fish and other aquatic life
dependent on oxygen.

Disease-causing agents -- Pathogenic organisms carried by sewage and industrial
wastes such as meat processing plants. Man may be exposed to such organisms by drinking untreated water, by eating improperly prepared foods, or swimming in contaminated water. Modern disinfection techniques greatly
reduce the danger from this type of contaminant.

Plant nutrients Substances, chiefly nitrogen and phosphorus, in sewage and
industrial wastes and farm drainage which stimulate the growth of aquatic life.
These nutrients are not removed by biological waste treatment processes, but they are converted from organic forms to mineral forms which are more usable by plant life. Aquatic life in the upper reach of Plantation Canal consistently shows the effects of nutrients in effluent from several sewage
treatment plants.




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