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Hydrologic studies in the Snake Creek Canal area, Dade County, Florida ( FGS: Report of investigations 24, pt.3 )

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Title:
Hydrologic studies in the Snake Creek Canal area, Dade County, Florida ( FGS: Report of investigations 24, pt.3 )
Series Title:
( FGS: Report of investigations 24, pt.3 )
Creator:
Leach, Stanley D
Sherwood, C. B ( joint author )
Geological Survey (U.S.)
Place of Publication:
Tallahassee
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[s.n.]
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Language:
English
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vi, 33 p. : illus., maps, diagrs. ; 23 cm.

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Subjects / Keywords:
Groundwater -- Florida -- Miami-Dade County ( lcsh )
City of Miami Gardens ( local )
The Everglades ( local )
Canals ( jstor )
Snakes ( jstor )
Creeks ( jstor )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
"Selected references": p. 33.
General Note:
"Prepared by the United States Geological Survey in cooperation with the Central and Southern Florida Flood Control District."
General Note:
Errata sheet tipped in.
General Note:
Author statement covered by label on cover and t. p.: By S. D. Leach and C. B. Sherwood.
Statement of Responsibility:
by C. B. Sherwood and S. D. Leach.

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University of Florida
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University of Florida
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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:
022573908 ( aleph )
01723255 ( oclc )
AES1340 ( notis )
a 63007792 ( lccn )

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Full Text
STATE OF FLORIDA
STATE BOARD OF CONSERVATION
DIVISION OF GEOLOGY
FLORIDA GEOLOGICAL SURVEY
Robert O. Vernon, Director
REPORT OF INVESTIGATIONS NO. 24 PART III
HYDROLOGIC STUDIES IN THE SNAKE CREEK
CANAL AREA, DADE COUNTY, FLORIDA
BY
C. B. SHERWOOD AND S. D. LEACH U. S. GEOLOGICAL SURVEY
Prepared by the UNITED STATES GEOLOGICAL SURVEY in cooperation with the CENTRAL AND SOUTHERN FLORIDA FLOOD CONTROL DISTRICT
Tallahassee
1963




FLORIDA STATE BOARD OF
CONSERVATION
FARRIS BRYANT Governor
TOM ADAMS J. EDWIN LARSON
Secretary of State Treasurer
THOMAS D. BAILEY RICHARD ERWIN Superintendent of Public Instruction Attorney General
RAY E. GREEN DOYLE CONNER
Comptroller Commissioner of Agriculture
W. RANDOLPH HODGES Director
ii




LETTER OF TRANSMITTAL
Jorida /eological Survey
1Callakassee
February 18, 1963
Dear Governor Bryant:
The Division of Geology is publishing as Part III of Report of Investigations No. 24, a report entitled, "Hydrologic Studies in the Snake Creek Canal Area, Dade County, Florida," prepared by C. B. Sherwood and S. D. Leach of the U. S. Geological Survey. The study was made as a part of the cooperative program of water studies between the Division of Geology and the Central and Southern Florida Flood Control District.
This is a part of a series of short papers recording the hydrology and geology of several areas in the District. An attempt has been made to relate the characteristics of the water resources existing before the construction of control structures in the District to the attitude of those resources after the control structures have been made operative.
These studies will be helpful to the District in managing the water resources, controlling the loss of water and in further design planning.
Robert O. Vernon, Director
and State Geologist
iii




Completed manuscript received
January 24, 1963
Published for the Florida Geological Survey
By E. O. Painter Printing Company
DeLand, Florida
Tallahassee, Florida 1963
iv




TABLE OF CONTENTS
Abstract __-_. 1 Introduction 1
Acknowledgments -.. .3 Previous investigations 3 Area of investigation 4 Climate 4 Topography and drainage 4 Geology 7 Method of investigation 7
Collection of data 10 Analysis of data 13
Change in storage and flow 13 Aquifer coefficients -------- 26 Summary 30 References ----- - 33
ILLUSTRATIONS
Figure Page
1 Greater Miami area showing major hydrologic features and the
area investigated ----------_ 2
2 Greater Miami area showing the configuration of the natural
drainageways and the coastal ridge 5
3 Photographs of salinity control structure near mouth of Snake
Creek Canal -6
4 Geologic section along Snake Creek Canal (adapted from U.S.
Corps of Engineers 1954, pl. 94) 8
5 Geologic section along line A-A' near Snake Creek Canal 9
6 Graphs of water levels at six selected wells and two canal stations, discharge near the control structure, control openings, and rainfall in the Snake Creek area for the period July 1960
to April 1961 __11
7 Stage and discharge of Snake Creek Canal at selected stations
on March 25-26, 1961, when-the control was closed 12
8 Hydrographs of stage and-discharge at selected canal stations
during test March 27-30, 1961 _14
9 Hydrographs of stage and discharge at selected canal stations
during flushing operation March 31 to April 1, 1961 15
10 Hydrographs of selected wells and canal stations March 25 to
April 3, 1961 16
11 Diagram of tidal backwater in a canal and progressive changes
of slope, directions of flow, and changes in storage of a tidal
canal (Parker and others, 1955, fig. 127) 18
12 Snake Creek Canal showing mean flow regime, March 25-26, 1961 19
V




ILLUSTRATIONS (Continued)
13 Vertical velocity profiles in midchannel for Snake Creek Canal
at West Dixie Highway on March 29, 1961 20 14 Snake Creek Canal area showing contours on the water table,
March 27, 1961 21 15 Snake Creek Canal showing average flow regime and water
level profile during March 27-30, 1961 22 16 Snake Creek Canal showing maximum and minimum discharge
regimes and water-level profiles during March 27-30, 1961 -- 23 17 Snake Creek Canal area showing contours on the water table,
March 29, 1961 25 18 Sketch showing selected wells in the Sunny Isles well field and graphs
and graphs showing drawdown in water levels under various 18 Sketch showing selected wells in the Sunny Isles well field
pumping conditions -- 27 19 Graphs showing relation between tidal fluctuations in Snake
Creek Canal and selected wells 29
vi




HYDROLOGIC STUDIES IN THE SNAKE CREEK
CANAL AREA, DADE COUNTY, FLORIDA
By
S. D. Leach and C. B. Sherwood
ABSTRACT
Snake Creek Canal was constructed primarily to drain parts of northern Dade County and southern Broward County, Florida. During dry periods, however, it conveys water from the Everglades seaward to replenish coastal sections of the Biscayne aquifer. A salinity-control structure at the mouth of the canal prevents the upstream movement of salt water and helps to maintain upstream water levels high enough to prevent salt-water encroachment into the aquifer. These hydraulic effects are made possible because of the high permeability of the aquifer and the excellent interconnection between the canal and the aquifer.
Hydrologic tests made March 25-26, 1961, on the flow system indicate that an inflow of 36 cfs (cubic feet per second) from Area B was required in the canal to maintain a water level of 2.7 feet above msl (mean sea level) at the control structure. This water is used to recharge the aquifer in the coastal ridge.
Future well fields of Metropolitan Dade County will withdraw as much as 200 mgd (million gallons per day) from the Biscayne aquifer in the western part of the Snake Creek Canal area. These large quantities of water will be derived chiefly by infiltration from the canal system and will greatly increase the amount of water needed to maintain desired levels near the coast. During drought periods this quantity could amount to more than four times the natural losses from the system.
INTRODUCTION
This study is one of a series of hydrologic studies of canal area made in cooperation with the Central and Southern Florida Flood Control District to provide data for use in formulating an overall water-control plan for southeastern Florida. The rapid growth of population in the Greater Miami area has indicated a need to extend the existing water-control system to include a large swampy area of anticipated urbanization, designated as Area B, west of the




2 FLORIDA GEOLOGICAL SURVEY city (fig. 1). However, an urbanization plan for Area B must also be designed to prevent flooding within the area, and to maintain careful water control in the coastal area to prevent flooding and salt-water encroachment.
SOUw RIVER CANAL
.E.. O............. ..C..L..
:--:-: ---:: j ....HO YWOOD
B,:AR A TB ARE
. CANAL
REPORT AREA A I':-'-':!-"1 .. ..
iT.-.'-,r '.- .- '. -' M IA M J
EXPLANATION "
REPORT AREA
AREA B
CONTROL STRUCTURES \
EXISTING
E-- C SCALE IN MILES
UNDER CONSTRUCTION 0 I 2 3 4 5 6
Fig. 1. Greater Miami area showing major hydrologic features and the area investigated.




REPORT OF INVESTIGATIONS NO. 24 3
The purpose of this study was to obtain a detailed description of the hydrologic environment in the Snake Creek Canal area and to provide quantitative definition of the following hydrologic factors:
1. The quantity of water needed to maintain a given bead near
the coast, for the control of salt-water encroachment.
2. The discharge rates at selected points in the canal system
under various controlled conditions.
3. Relation between ground-water movement and canal flow in
different canal reaches.
The investigation was made in 1961 by personnel of the Water Resources Division of the U. S. Geological Survey under the general supervision of A. 0. Patterson, district engineer, Surface Water Branch, Ocala, and M. I. Rorabaugh, district engineer, Ground Water Branch, Tallahassee. It was under the immediate supervision of J. H. Hartwell, engineer-in-charge, Surface Water Branch, Miami, and Howard Klein, geologist-in-charge, Ground Water Branch, Miami.
ACKNOWLEDGMENTS
The writers are indebted to the Central and Southern Florida Flood Control District, for furnishing complete information on their installations in the study area, and for operating control structure 29 during the test. Appreciation is expressed to the Dade County Public Works Department for information on the watercontrol system in the area, and the City of North Miami Beach for providing the equipment for aquifer tests and records of pumpage from their municipal well field.
PREVIOUS INVESTIGATIONS
A brief paper by Parker (1951) discusses the geologic and hydrologic factors in the perennial yield of the Biscayne aquifer in southeastern Florida, and a later report by Parker and others (1955) presents a comprehensive account of the geology and water resources of southeastern Florida. Schroeder and others (1958) summarize the hydrology and geology of the Biscayne aquifer and evaluate the perennial yield of the aquifer from data obtained since 1950. Stallman (1956) gives the results of electrical analog studies of the hydrology of intercanal areas of Dade County. Klein and Sherwood (1961) describe hydrologic conditions in the vicinity of Levee 30, which is southwest of the Snake Creek Canal area.




4 FLORIDA GEOLOGICAL SURVEY
AREA OF INVESTIGATION
The Snake Creek Canal area is in the northernmost part of the Greater Miami area, Dade County, Florida. The area investigated extends about 21/2 miles north and 2 miles south of Snake Creek Canal from Biscayne Bay to the eastern edge of Area B (fig. 1), a distance of about 11 miles. Supplemental water-level data were collected in the northern part of Area B.
CLIMATE
The climate in the Miami area is subtropical. Rainfall averages approximately 60 inches per year, about 75 percent of which occurs during the period May through October. This wet period includes both the normal rainy season and the hurricane season. The average annual temperature is approximately 750F.
TOPOGRAPHY AND DRAINAGE
The dominant topographic features of the area are the coastal ridge and the natural drainageways or transverse glades which cut through the coastal ridge from the Everglades. The configuration of the ridge and the drainageways is shown in figure 2. The land surface ranges from 5 to 7 feet above msl at the eastern edge of the Everglades and along the transverse glades, and from 9 to 20 feet above msl on the coastal ridge.
Snake Creek Canal, the main drainage features of the area, flows eastward from Levee 33 to Biscayne Bay (fig. 1). The canal is the primary drainage channel for a large part of Area B, as well as for the northern part of the Miami area. Several secondary canals in the western part of Area A drain to Snake Creek Canal. South New River Canal in Broward County and Snake Creek Canal are connected by a north-south canal along the eastern edge of Area B (fig. 1).
Flow in the canal system is maintained chiefly by ground-water discharge. During periods of heavy rainfall, considerable surface drainage is collected from low areas on the coastal ridge and from Area B. The flow in Snake Creek Canal is regulated by the operation of a control structure (fig. 3), about 11/4 miles upstream from Biscayne Bay. Submerged sluice gates in the structure are manipulated to provide maximum discharge for flood protection during periods of heavy rainfall and to prevent salt-water encroachment into the aquifer and into the upper reaches of the canal during dry periods.




REPORT OF INVESTIGATIONS NO. 24 5
SOUTH NEW RIvR CA NA
S VAKA
BROWARD COUNT CRK CANAL P
DADE COUNTY
%We
BISCAYNE CANAL
" LITTLE RIVERe
N .,
EXPLANATION
COASTAL RIDGE
F.IGLADE LINE SCALE IN MILES
Fig. 2. Greater Miami area showing the configuration of the natural drainageways and the coastal ridge.




6 FLORIDA GEOLOGICAL SURVEY
Fig. 3. Photographs of salinity-control structure near mouth of Snake Creek Canal.




REPORT OF INVESTIGATIONS NO. 24 7
GEOLOGY
The area crossed by the Snake Creek Canal is underlain by the permeable limestone, sandstone, and sand of the Biscayne aquifer. The aquifer underlies the land surface to a depth of about 200 feet near the coast and to about 55 feet at the western end of the Snake Creek Canal. The aquifer is predominantly limestone at the coastline and in Area B, but it varies sharply between limestone and sand throughout most of the coastal ridge. The changes in the shallow, subsurface materials are shown in the geologic section in figure 4. The section also indicates that low areas along the natural drainageways are covered by several feet of muck or organic material. The nature of the deeper materials within the aquifer is shown in the west-east geologic section, along Snake Creek Canal, figure 5. In general, the most permeable zones occur in the lower part of the aquifer.
Supply wells in the Sunny Isles and Norwood well fields, operated by the City of North Miami Beach (fig. 14), tap highly permeable limestones at depths ranging from 60 to 120 feet below the land surface. Individual wells in these well fields yield as much as 2,000 gpm (gallons per minute) with a water-level drawdown of approximately 6 feet. Combined pumpage from the two well fields during 1960 ranged from 5.4 to 14.6 mgd.
METHOD OF INVESTIGATION
Hydrologic tests of the Snake Creek Canal area flow system were made during the period March 25 to April 1, 1960. The control was closed March 25-26 and the water level was held in equilibrium at a high stage of 2.7 feet. Measurements were made during this condition at several points along the canal to determine the flow required to maintain the head existing at the control structure. The structure was opened on March .27 and then closed on March 30 to induce abrupt changes in area-wide water-level conditions. On March 31, the control was opened for 41/ hours to flush out salt water that was trapped upstream from the control structure during the test.
Observations and analyses were made of the changes in water levels and flow that resulted from the operation of the control structure. Data collected during previous investigations and during a continuing observational program were used to supplement the test data.




8 FLORIDA GEOLOGICAL SURVEY
ALTITUDE.IN FEET, REFERRED TO MSL
NE-EE 33
-w -_-_ _-_ _-_ _tUSHWY 27
h
RED ROAD RED ROAD
oDOUGLAS ROAD 41T DOUGLAS ROAD
STA E ROAD 7 MSATE ROAD 7
_IAMIl GARDENS
DRIVE
CONTROL
oL
)---DIXIE HWY
-CONTROL CAYNE BAY
Fig. 4. Geologic section along Snake Creek Canal. (Adapted from U. S. Corps of Engineers 1954. pL94W




A A' w >
20 ) CD aO 0t 2 -0 O N t
EXPLANATION -50 60 --60 LIMESTONE
0 L IN M-70 0 ~-80 SHELLS -8
. ... .I .. S 2 10
,G110,
4j ~~ A' SL0
10CLAY -110
--13
S-20 20
04 500 5000
Fig. 5.0 GeloicEXPLANATION Lij 60 .6 ~~LIMESTONE -0
-130 o aoo oo -30
F e e -80 i l A--80A
- 9 0 0G 9 0 "
. i~l! i SAND -1I00
G: 113' LA -110
S-130 0 -FoLo I o0 -130
Fig. 5. Geologic section along line A-A' near Snake Creek Canal.




10 FLORIDA GEOLOGICAL SURVEY
Discharges at selected points in the canal were computed during the test periods from stage-area and deflection-mean velocity relationships. Current-meter measurements were made by conventional methods and, from these measurements, the crosssectional area and the mean velocity of the canal were determined under various conditions. Continuous stage records were obtained from water-stage recorders, and continuous records of an index of velocity were obtained from deflection meters installed at midehannel. A deflection meter consists of an underwater vane attached to a vertical shaft that is free to rotate. The amount of angular rotation caused by the force of the flowing water is recorded in deflection units on a chart.
Discharge was thus computed from the basic formula Q = AV, in which Q is the discharge, in cubic feet per second A is the cross-section area of the canal, in square feet, from the
stage-area relationship
V is the mean velocity of flow, in feet per second, from the
deflection-mean velocity relationship.
COLLECTION OF DATA
The continuing water-records program in the area includes 22 observation wells, a water-level recording station in Snake Creek Canal at Red Road, and a water-level and discharge measuring station in the canal at West Dixie Highway (fig. 14). Six of the observation wells are equipped with water-level recording gages. Records from these data-collection stations provided considerable background data on the fluctuation of water levels throughout the drainage area.
For use during the test period, 28 additional shallow observation wells were drilled. Water-level recorders were installed on three of these wells and on seven privately owned wells. Two portable deflection meters and four water-level recorders were installed in the canal, and a water-level recorder was installed near the mouth of the Oleta River. All observation points were referred to mean sea level datum by spirit level. The locations of all datacollection sites are shown in figure 14.
Water-level fluctuations in six selected wells and at two canal stations, discharge of the canal near the control structure, and rainfall measured at Douglas Road are shown for the period July 1960 to April 1961 in figure 6. The effects of control operations during the test period, March 25 to April 1, 1961 are shown by sharp fluctuations of discharge and water levels.




REPORT OF INVESTIGATIONS No. 24 11
.1960 1961 JULY AUG. SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR.
1O2 1020 1020 020 1020 1020 1 W 0
WELL 672 CANAL EXTENSION COMPLETED
.-ELL G6 DA/LY HIGH WELL G970
Id
> i.. .-.. .
LA
4 3
U) :-
n ELL G 850
0
- 4 .
WEL /5 z N
SNAKE CREEK CANAL
_j I I d J I ATRED ROAD
4 _
I NAKTWXE EEK CANA1
S S NAKE CREEK CANAL
A DIX ATHW .DIXIEHW
0 ,,
oc
c200
L
10
4800SCONTRAN
0400 h
0
- I-COTL
.z STATUS
-J-JzATDOUGLAS ROAD
Lz
.(
Fig. 6. Graphs of wate levels at six selected wells and two canal stations, discharge near the control structure, control opening, and rainfall in the Snake
Creek area for the period July 1960 to April 1961..




12 FLORIDA GEOLOGICAL SURVEY
On March 25 and 26, observations were made throughout the test area to determine the magnitude and direction of flow required to maintain a constant water level of 2.7 feet above msl at the control structure. Stage and discharge of Snake Creek Canal at selected stations during this period are shown in figure 7.
MARCH 25 1961 MARCH 26
6:'00 12:00 6 1200 00 6:00
. .A.,t P.. . M.. . . 60 0 .. . . .
100
o SNAKE CREEK CANAL
6 .AT RED R AD SNAKE CREEK CANAL Sr..... .. T MIAMI GARDENS DRIVE
o .. ......................
m SNAKE CREEK CANAL
CAT W DIXIE HWY
-4
SNAKE CREEK CANAL
AT RED ROAD _A RA
0
_C ? kI-- ... ,,. ,. -_
SNAKE CREEK CANAL
_..............ISNAK CREEK CANAL
~2. . ____ DOUGLAS ROAD >A 1 SNAE CREEK ANANL uj AT MIAMI GARDENS DRIVE
Fig. 7. Stage and discharge of Snake Creek Canal at selected stations on
March 25-26, 1961, when the control was closed.
After the four bays of the control structure were opened at 10:15 am. on March 27, water-level fluctuations were measured in the observation wells, and continuous records of -stage and streamflow were collected in Snake Creek Canal at West Dixie Highway, at Miami Gardens Drive, and at Red Road. The discharges measured on March 28 at the three stations along the canal during a tide cycle and near the time of opening (10:15 a.m. March 27) and closing (9:00 a.m. March 30) the control dam are shown in the following tabulation:




REPORT OF INVESTIGATIONS NO. 24 13
Red Road Douglas Road Miami Gardens Drive March 27
Discharge Discharge Discharge Time (cfs) Time (cfs) Time (cfs) 12:10 p.m. 639 11:00 a.m. 637 2:40 p.m. 706 12:10 p.m. 1,010 12:20 p.m. 2,310 1:35 p.m. 1,010
2:55 p.m. 960
March 28
9:50 a.m. 333 8:05 a.m. 240 8:40 a.m. 189 12:05 p.m. 496 10:30 a.m. 516 10:35 a.m. 1,130 1:45 p.m. 550 1:30 p.m. 780 11:40 a.m 1,340 3:50 p.m. 613 4:35 p.m. 734 1:40 p.m. 1,550
March 30
9:25 a.m. 154 7:50 a.m. -421 11:25 a.m. 244 (- indicated flow upstream)
Fluctuations of stage and discharge at four canal stations during the test period are shown in figures 8 and 9. Fluctuation of-levels in selected wells and canal stations during the period March 25 and April 4 are shown in figure 10.
Starting near low tide at 1:30 p.m. on March 31, a 41/2-hour flushing operation was conducted to remove the salt water that was trapped in the canal upstream from the salinity-control structure. This flushing operation was scheduled as part of the test because its effects are similar to those caused by normal operating procedures for removing debris from the canal. The abrupt changes in water level and discharge caused by this operation are shown in figure 9. The additional rise in water level and discharge during the morning of April 1 was caused by heavy rainfall in Area B.
ANALYSIS OF DATA
CHANGE IN STORAGE AND FLOW
Changes in storage and flow within the system depend chiefly upon: (1) the quantity of rainfall recharging the system, (2) the quantity of inflow from the Everglades by canals and by underflow,
(3) operation of the control structure, and (4) tidal backwater in the canal.
The correlation of these factors is shown by the hydrographs in figure 6. Each heavy rainfall caused a corresponding rise of the water table and the canal stage, except in the lower reaches of the canal where levels generally are regulated by the control




14 FLORIDA GEOLOGICAL SURVEY
MARCH28 1 MARCH 29 MARCH 30
_ __W ZM AI
I aroDE ORD,
t 270 1
I II =
I I
, ..COMD.....
1-n ---&O SARACEE
test-March 27-3L, 19O1.
structure. During long periods of heavy rainfall, ground-water levels rise to 4 or 5 feet above mal in areas near the coast (wells G850 and D151). Water levels in areas near the coast decline rapidly as the rainfall decreases, but in upgradient areas the release of water from storage is slower (wells G72 and G970) .
The quantity of ground-water inflow from the Everglades areas varies with the gradient toward the coast. During flood periods, the hydraulic gradient across Area B and the coastal ridge is initiaIy slight because of high water levels underlying the ridge. However, as coastal ground-water levels decline, after the control is opened, large quantities of water from the west drain into the
Wt _____~~~~~~1~~ I-,N -- _RED OAD-COEROL
Fig 8.analHydrographs of stagesystem and the aquifer. Thare control selected canal stations during test March 27-30, 1961.
structure. During long periods ofto discharge this excess water. The extension fd-water levSnake reek Canal to the western ede of Areas near the coast (wells G850 and D151). Water levels in areas near the coast decline rapidly as the rainfall decreases, but in upgradient areas the release of water from storage is slower (wells G72 and G970).
The quantity of ground-water inflow from the Everglades areas varies with the gradient toward the coast. During flood periodsthe hydraulic gradient across Area B and the coastal ridge is initially slight because of high water levels underlying the ridge. However, as coastal ground-water levels decline, after the control is opened, large quantities of water from the west drain into the canal system and the aquifer. The control structure is kept open for long periods to discharge this excess water. -The extension o f Snake Creek Canal to- the western edge of Area B, during October




REPORT OF INVESTIGATIONS NO. 24 15
MARCH 31 1961 APRIL I
6 00 200 6:00 12.00 6:00 1.0
AA M PA P.M. PM
200C
SNAKE CREEK CANAL SAT W. DIXE HWY
160C
L.
C120C
Z
00
U
c4 r 00C
o." SNAKE CREEK CANAL a .: L6~L~ I. ARDENS DRIVE
3. _.. ...... _...*----4
..0
. SNAKE CREEK CANAL
SAT RED ROADDOUGLAS OAD /
w
1.5 \ / ""
. SAK CE CN
w
00
z --c
<. -- C K SNAK CREEK CANAL
.5
~ATDO'GLA S ROAD w o1,
0/
o
Li- R. w SNAKE CREEK CANAL
w AT MIAMI GARDENS DRIVE
-.
w SNAKECRECNL
> ATW DIXIE HWr
w
- .
Fig. 9. Hydrogr~phs-of stage -and. discharge- at -selected canal stations during
flRushing operation March 31 to April 1, 1961.




16 FLORIDA GEOLOGICAL SURVEY
MARCH 1961 APRIL
25 26 27 28 29 3O 3 1 2 3
C ....-... WEL L 6970
_Ic
03
CANAL
-J3. __ __
WELL 6/053- WEST END)
0
WELL G 153.0 GANA T
WELL L052
L2.0 _____ V_OLETA RIVER-.
L 51ELL G 85/
ELL66
2.(
WELL SI85
WELL S/442,\ --ELL S/438 .Fig. 10 Hydrographs of selected wells and canal stations March 25 to April 3, 1961.




REPORT OF INVESTIGATIONS NO. 24 17
1960, had a marked effect on water levels in that area as shown by wells G72 and G970 in figure 6. The water level in well G72 near the western end of the canal declined sharply when the canal was completed on October 28, 1960, and by the end of February 1961, had declined to less than 4.0 feet above msl. The gradient between well G72 and the control structure at this time was less than 1.5 feet in 17 miles, or 0.09 foot per mile. As the canal has been extended, higher flood discharges through the control structure will probably occur; however, the duration of high discharge should be shorter because of the more rapid drainage of Area B.
When the control structure is open, a large part of the system is affected by tides. The magnitude of the effect decreases upstream and depends upon the amount of the gate openings and the rate of discharge. Tidal fluctuations of 0.3 of a foot were observed at the western end of the canal during the test; however, when the control was open during flood periods prior to the test very little fluctuation occurred in the canal west of Red Road. Maximum discharge from the canal occurs 1 to 2 hours before low tide, and minimum discharge occurs at high tide (fig. 8). Figure 11, from Parker and others (1955, fig. 127), shows progressive changes of slope of the water surface, direction of flow, and changes in storage in a tidal canal.
The changes in flow and stage caused by opening or closing the control structure during the test correspond generally with the changes caused by a falling or rising tide, except for rate and magnitude. The extent of area affected within the flow system depends chiefly on the length of time the control structure remains open or closed, and the antecedent hydrologic conditions. The hydrographs in figure 10 indicate that a period of several days is required for water levels throughout the area to adjust fully when the control is open or closed. The hydrographs also show the effects of the difference in permeability between the sandy materials in the coastal ridge and the limestones underlying Area B. The water level in well G970, half a mile south of the canal and 15 miles inland, responds more readily to changes in canal stage than the water level in wells G1052 and S1442 which are closer to the canal within the coastal ridge.
The hydrographs in figure 7 show the canal discharges on March 25-26 when an average water level of 2.7 feet above msl was maintained at the closed control structure. A strong easterly wind was the chief factor contributing to variation of discharges. The




18 FLORIDA GEOLOGICAL SURVEY
SC A
W LWA L
~~IN BAY
a an prr
ini
slope, direction of flow,-and changes in storage of a tidal canal (Parker and
others, 1955, figure 12.7).




REPORT OF INVESTIGATIONS No. 24 19
mean discharges at Red Road, Miami Gardens Drive, and West Dixie Highway for this period are shown schematically in figure 12. These discharges were 36, 32, and 16 cfs, respectively. The discharge of 36 cfs at Red Road represents the inflow required from Area B on March 25-26 to maintain the water level at 2.7 feet at the control. The measurements indicate that seepage from the canal to the aquifer increases rapidly in the reach between Miami Gardens Drive and the control structure.
SN _I
EXPLANATION
S DIRECT OF FLOW AND DISCHARGE.CFS
OUTFLOW ".CANAL REACH,CFS
NF INFLOW IN CANAL REACH,CFS
' tit'tREAE CHANNELS STORAGE
IS CANAL REACH.CFS
Fig. 12. Map of Snake Creek Canal showing mean flow regime, March 25-26.
1961.
The hydrographs in figure 8 give a comprehensive picture of the fluctuations of water levels and discharges in the flow system during the test period of March 27-30 when all four gates of the control structure were open. The gates were opened at 10:15 a.m. on March 27, at low tide, to induce the maximum possible change in water level and flow throughout the test area. The control structure was left open, as long as it was feasible to do so, to establish relatively stable drainage conditions within the flow system. The length of the period was limited by the rapid intrusion of salt water up the canal. The discharge at West Dixie Highway during each tide cycle on March 27-30, is shown in figure 8. The anomaly in the discharge graph at West Dixie Highway immediately preceding a tidal peak discharge, is probably related to the upstream movement of the salt-water wedge in the lower reach of the canal. The effect of this wedge on discharge is strikingly shown in figure 13 by the velocity profiles in a vertical section at midchannel of the canal.
The sharp oscillations in flow and water level (fig. 8, 9) were caused by the abrupt closing of the control.
The configuration of the. water table on March 27 under relatively unchanging conditions before the opening of the control




20 FLORIDA GEOLOGICAL SURVEY
'4
z
G
a
-1
4
z
a
TIME MEAN VELOCITY
8:18 A.M. -0.15 ft/sec 2 ---- 9:15 A.M. .12 ft/sec 10:03 A.M. .66 ft/sec 10:54A.M. 1.12 ft/sec 12:20P. M. 1.39 ft/sec 1 CANA BED _2:35 P.M. 1.67 ft/sec
- ---UPSTREAM --0 -DOWNSTREAM--I 2
VELOCITY, IN FEET PER SECOND
Fig. 13. Vertical velocity profiles in midchannel for Snake Creek Canal at
West Dixie Highway on March 29, 1961.
structure, is shown by the contour map in figure 14. The groundwater gradients (fig. 14) and the canal discharges (fig. 12) on March 25-26, when the control structure was closed, indicate that water was entering the aquifer from the canal in all reaches east of Red Road. A comparison of the hydrographs of well G970 and the adjacent canal station in figure 10, shows the ground-water gradient in Area B to be toward the canal at this time. When the control structure is closed, the ground-water gradients are steepest and the seepage from the canal is greatest near the coast and




hAA
iI I' ,
..- - *"" at- .. -5 **T 5 162 2
.0 wt
-~ 011067 340
,....oo...... ...
"IkT......o- i U "l.7 jwW, OIL. i. I.
i '0 6G I /
IIOS
B E .... . ....... ... ..5 .
IKNLANATION, BS
WATER I COTR IN... ...E1
, ... IN,,,RED,-- ,o
Fig. 14. Snake Creek Canal area showing contours on the water table, March
27, 1961.
U04110
STA0. AF452 itN DEO ION, ETE z ;x A -u WATER*11?ALI RCOORIN P197 jJ !I.0.,01 1 14 ABV MEN SE LEVL SUNN ISLE I
4~7 1961.00
STAFP A09 rIrGS5




22 FLORIDA GEOLOGICAL SURVEY
through the area of limestone quarries between the canal and the Oleta River. In these areas the shallow materials are highly permeable.
As shown in figure 14 ground-water gradients south of the Snake Creek Canal are reduced by the effects of the controlled reach of the Biscayne Canal except in the area near the coast; north of the Snake Creek Canal the water table slopes northeastward toward the coast and toward the uncontrolled reach of South New River Canal in Broward County (fig. 1).
The secondary canals which connect Snake Creek Canal to the major canals of the regional water-control system (fig. 1) are highly constricted in many places and convey very little water, except during flood periods. Thus, it is evident that most of the water that enters the canal during extended dry periods is derived from ground-water storage in the western part of the coastal ridge (fig. 2) and in Area B.
The average flows and water levels which occurred when the control structure was open are shown in figure 15. The magnitude and direction of flow at any time can be obtained from the hydrographs in figure 8. The maximum and minimum discharges and water levels in the canal during this period are shown in figure 16.
EXPLANATION
. z AND DISC RGE.C FS
4.-- NFLOW IN C REACH.CFS
.ECREASE IC -A NEL STORAGE
Fig. 15. Snake Greek Canal showing average flow regime and water-level profiles during March 27-30. 1981.
NA A L REA:.CFSN
-4'
Fig. 15. Snake Creek Canal showing average flow regime and water-level profiles during March 27-30, 1961.




REPORT OF INVESTIGATIONS NO. 24 23
EXPLANATION
MRIUCTO OFF LOA'LND D OSCIIURGECFS
MA MXIMUM DISCI XE
Fig. 16. Snake Creek Canal showing maximum and minimum discharge
regimes and water-level profile during March 27-30, 1961.
Changes in storage in the canal occur as the water level changes. The quantitative amounts of these storage changes have been computed from the water-surface area and change in stage during the test period. The surface area changes very little with changes in stage because the side slope of these canals and rock pits are steep. The tabulation below includes the area of Snake Creek Canal and the connecting secondary canals and rock pits.
Surface area,
Canal reach (square feet)
Control structure to West Dixie Highway ...... .. ..171,000 West Dixie Highway to Miami Gardens Drive _..1,280,000 Miami Gardens Drive to Douglas Road .. _9,872,000 Douglas Road to Red Road _. 8,238,000
MINIMUM DISCHARGE-5
Red Road to U. S. Highway 27 3,485,000
The rate of change in canal storage was computed by the formuanQt=tA where Q is the discharge from storage, in efs,
A is the water-surface area in square feet, d is the average decline in water level, in feet, (static level at opening of control to mean tide level at closing), and t is the time in seconds of the period under consideration. The computations for the average discharge
tt
A isthewate-sufaceare in quae fet, is he verae dCin
inwtrlvl4nfe,(ttclee toeigo oto oma tid ee tcoigadti h iei eod ftepro udrcnieain h opttin o h vrg icag




24 FLORIDA GEOLOGICAL SURVEY
from storage in the canal reach between the gaging stations for the period March 27-30 are, as follows:
West Dixie Highway to Miami Gardens Drive:
Ad 1,280,000 x 2.17 11 cfs
t 254,700
Miami Gardens Drive to Douglas Road:
S- 9,872,000 x 2.00 -= 78 cfs
254,700
Douglas Road to Red Road:
Q- 8,238,000 x 1.82 = 59 cfs
254,700
Red Road to U.S. Highway 27:
S 3,485,000 x 1.52 21 cfs
254,700
The mean discharges for the test period March 27-30 at West Dixie Highway, Miami Gardens Drive, Douglas Road, and Red Road were 1,011, 832,625, and 445 CFS, respectively, as shown in figure 15. The discharge at Red Road, 445 cfs, was the average inflow from the Everglades and Area B.
The average ground-water inflow along reaches between the canal discharge stations was computed by the following formula: Qc = Q, Q2 Q,, where Q, is the inflow from the aquifer, in cfs, Q, is the discharge at the downstream station, in cfs, Q2 is the discharge at the upstream station, in cfs, and Q. is the discharge from (decrease in) the canal storage, in cfs, from a foregoing paragraph. The computations of the mean groundwater inflow in the canal reach between the gaging stations are shown in figure 15 and are as follows:
West Dixie Highway to Miami Gardens Drive:
Q9 = Q1 Q2 Q. = 1,011 832 11 = 168 cfs
Miami Gardens Drive to Douglas Road:
Qg = Q1 Q2 Q. = 832 625 78 = 129 cfs
Douglas Road to Red Road:
QC=Q1 Q2- Q = 625 445 59 = 121 cfs
Red Road to U.S. Highway 27
Q,= Q1 Q2 Q.= 445 0 21 = 424 cfs
The configuration of the water table on March 29 before the closing of the control is shown in figure 17.
The sharp decline of the water level in the canal after the opening of the control caused ground-water inflow to the canal in all




$ EXPLANATION "
WATE-TAILE ONTOUR IN T ABOV iA 1160Il
4og L 01161 1.15
STAFF AG r
DEFLECTION METER ..
WATC-LEVEL CORDING GABE
......... ;, j- A4L .. .. -i' - ----. 151 ...... -,o' .... 51Aoos
oeeso to
-.---A ". P4' 4
-- -- .."-- ,-, ,0A 9010 4-1.50
. .... A45 04 T O EN
I.-~ I I OE
1051 11 ~~441 V,
010050
Fig. 17. Snake Creek area showing contours on the water table, March 29, 1961.
t.5
F 6 62
If '00n




26 FLORIDA GEOLOGICAL SURVEY
reaches (fig. 10, 17). The hydrographs in figure 8 indicate that the discharge at each gaging station in the canal declined very slowly during the test period. This was because of the sustained inflow of ground water. However, if the control structure were left open for an extended period, ground-water storage would be depleted, and the discharge in the canal would decline steadily.
AQUIFER COEFFICIENTS
The principal hydraulic properties of an aquifer may be expressed as coefficients of transmissibility (T) and storage (S). The coefficient of transmissibility is defined as the amount of water, in gallons per day, at the prevailing temperature, transmitted through a 1-foot strip of saturated thickness of the aquifer under a hydraulic gradient of 1 foot per foot. The coefficient of storage is defined as the unit volume of water released from, or taken into, storage per unit surface area of aquifer per unit change in the component of head normal to that surface.
Two short aquifer tests were conducted to define the aquifer coefficients in the vicinity of the Norwood and Sunny Isles well fields of the City of North Miami Beach. In addition, the approximate coefficient of transmissibility in several areas along the canal was computed by a method involving the cyclic fluctuation of ground-water levels caused by tides in the canal.
The two aquifer tests were made by pumping selected municipal supply wells in the well fields (fig. 14) and observing the drawdown of water levels in nonpumping supply wells and in observation wells. The supply wells are developed in beds of highly permeable limestone that are overlain by 60 to 100 feet of less permeable sandy limestone and sand. The layout of the wells in the Sunny Isles well field and the drawdown of water level in selected wells during various pumping conditions are shown in figure 18.
The drawdown data collected during the aquifer tests were adjusted to correct for fluctuations caused by factors other than pumping-chiefly, a steady rise in regional water levels caused by operation of the salinity control- and were analyzed by use of a family of leaky aquifer-type curves developed by H. H. Cooper, Jr., U. S. Geological Survey, from a method outlined by Hantush (1956). This method provides a means to compute the values of the coefficients of transmissibility and storage of the producing zones, and the coefficient of leakage of the less permeable beds that overlie the producing zone. The coefficient of leakage may be




REPORT OF INVESTIGATIONS NO. 24 27
*Io0
3A
RECORDING
8 GAGE 0
356 "3
4
- 173 Ft II
9:00 12:00 3:00 6:00 DISTANCE FROM PUMPED WELL, IN FEET AM. M P.M. P.M. 100 200 30 400
"- I I I i I "___T WJ PUMP ON WELL NO.3--0 -----8
PUP 000-N4I
JUNE 9,1961 J 109 Z PPPUMPING WELL NO.W11 4 800 GPM
0 PUMP OFF/ r0. / JUNE 9,1961 r 4"xPUMPING WELL NO.11
< JUNE 13,1961 800 GPM r --,WELLS NO. 410-Ir11.
0 0.2 PUMPING 2400 GPM,TOTAL
I I I ,I I Il
Fig. 18. Sketch showing selected wells in the Sunny Isles well field and graphs showing drawdown in water levels under various pumping conditions.
defined as the quantity of flow that crosses a unit area of the interface between the main aquifer and its semiconfining bed if the difference in head between the main aquifer and the beds supplying the leakage is unity. Although the characteristics of the aquifer do not ideally match the theoretical conditions assumed in this method of analysis, the determined coefficients provide valuable indications of the capacities of the aquifer.
The computed coefficient of transmissibility and storage for the well field areas ranged from 2.0 to 2.5 mgd per foot and 0.1 to 0.2, respectively, and the coefficient of leakage ranged from 20 to 30 gpd (gallons per day) per square foot per foot of head differential. The magnitude of the leakage coefficient indicates that the drawdown caused by long-term pumping would be reflected at the water table and that infiltration would occur readily from surface water sources such as the Snake Creek Canal.




28 FLORIDA GEOLOGICAL SURVEY
The configuration of the water table between the Sunny Isles well field and the canal in figure 14 indicates that water was flowing from the canal toward the well field at that time. During extended periods of drought and heavy pumping, a large part of the water withdrawn from this well field would be derived from the canal and, as a result, the drawdown in the well-field area would be minimized. Thus, the possibility of maintaining the well field, which is near the coast and close to the salt front in the aquifer, is largely dependent upon the effectiveness of the water-control system to maintain the canal level high enough to prevent further intrusion of salt water. The proximity of the salt front in the aquifer is indicated by the chloride content of more than 8,000 ppm (parts per million) in water samples collected at a depth of 57 feet below the land surface in well D151 (fig. 14).
The tidal data collected from wells near the canal were analyzed by a method which relates the time lag and stage efficiency of the tidal fluctuations in the aquifer and the canal to the value of T/S for the aquifer (Ferris 1951). An approximate value for T was computed using values for S determined by the pumping test methods and by examination of well-log data. The equation relating the transmissibility of the aquifer to the ratio of the range of ground-water level fluctuation to the range of the tidal fluctuation in the canal can be simplified if the range ratio is plotted on a logarithmic scale against the distance from the suboutcrop to the observation well on an arithmetic scale. Then the equation may be written as follows:
T 4.4 x2 S
to
T = coefficient of transmissibility, in gallons per day per foot
S = coefficient of storage (dimensionless) t, = period of the stage fluctuation, in days
x = distance with the observation well to the surface-water contact with
the aquifer (suboutcrop), in feet
x = change in x over one log cycle
The equation relating the time lag between the occurrence of a given tidal peak or trough in a well and the corresponding state in the canal to the value of T/S for the aquifer can be written
T 0.6x2t0S Where t, is the lag in time, in days.
t12
Tidal data from selected wells, and computations using both methods are shown in figure 19. In both cases the effective distance to the offshore outcrop is assumed to be half the canal width (60 feet). The error introduced by this assumption would be small




REPORT OF INVESTIGATIONS NO. 24 29
because the width of the canal is small in comparison to the distance to the observation wells. In theory, however, the intercept of the line established by the plotted data with the line of zero time lag, or 100 percent stage efficiency, would indicate the distance from the shoreline to the outcrop.
RANGE RATIO AL -AN~ ROUNDb-WAt fl-i
0 msTIDAL RANGE, GANAL TIME LAG IN HOURS
oi m j 5 01 11-0304CS 2 ] 4 5
2t 1440 T= S.6OXT
S T-3.4XIO6 GPD per Ft.
1600 -- =0u10.
200
4ooTT=2.4xioS
~zo ____T WOO P'5 =.I
1- -V.I- ---______ __ __ _- I 1 24
If o = .
T4 eX I J 0## per pr.
(. __-_" Q 1100 ~-. -V..
12 .00 1 .. J T= _____H
T12 ~ 601 4
400 T=2.4 X- -107.. ... .
If S-0,15 G1053 "
_______________A&___ ____ A=3 HOURS__Fig. 19. Graphs showing relation between tidal fluctuations in Snake Creek Canal and selected wells.
Coefficients of transmissibility computed by these methods (fig. 19) were about 3.5 mgd per foot within the coastal ridge. This value is appreciably higher than those computed from aquifer test data (2.0 to 2.5 mgd per foot) and probably not as reliable, but provides a useful indication of the capacity of the aquifer, if no other data were available. Computations based on tidal data from well G970 in Area B, for example, indicate a coefficient of transmissibility of more than 5.0 mgd per foot. This value seems high for an area where the aquifer is only 75 feet thick (Schroeder,. 1958), but it is supported by both the known occurrence of highly permeable materials in that area and by studies of underflow along Levee 30 in the western edge of Area B where Klein and Sherwood (1961) indicate a coefficient of transmissibility of 3.6 mgd per foot where the aquifer is only 55 feet thick.
The high permeability of the aquifer and excellent interconnection between the canal and the aquifer in Area B indicate that this reach of the Snake Creek Canal system would be a highly




30 FLORIDA GEOLOGICAL SURVEY
desirable area for the location of large future well fields. Withdrawals as high as 200 mgd are proposed from well fields of Metropolitan Dade County in the western part of the Snake Creek area by the year 2000. During dry periods these well fields will be largely dependent on recharge by induced infiltration from a network of secondary canals connected to Snake Creek Canal.
SUMMARY
The Snake Creek Canal drains the northern part of the Greater Miami area and is the main drainage canal for the northern part of Area B. Flow in the canal is maintained chiefly by the inflow of ground water, but considerable surface runoff is introduced from low areas on the coastal ridge and from Area B during flood periods. Canal discharge is regulated by a control structure near Biscayne Bay to provide maximum flood protection and to main maintain water levels high enough to retard salt-water encroachment during dry periods.
The area crossed by the Snake Creek Canal is underlain by the highly permeable Biscayne aquifer, which extends from the surface to a depth of 200 feet at the coast and about 55 feet at the western end of the canal. Natural drainageways that connect Area B with Biscayne Bay are bottomed by several feet of material of relatively low permeability.
Ground-water levels can be effectively raised or lowered throughout the drainage area by manipulation of the control structure. When the control structure is open, ground water flows toward the canal and the canal flow increases toward the bay. When the control structure is closed canal levels near the coast are generally higher than ground-water levels and appreciable groundwater recharge from the canal occurs.
Information collected during a test on March 25-26, 1961, indicated that an inflow of 36 cfs from Area B was required to maintain a water level of 2.7 feet above msl near the coast when the control structure was closed. Ground-water gradients and canal discharges indicate the canal was recharging the aquifer throughout the system east of Red Road under these conditions. The secondary canals which connect Snake Creek Canal to other major canals of the regional water-control system are constructed in many places and convey very little water except during flood periods. Thus, most of the water entering the canal during extended dry periods is derived from ground-water storage in the western part of the coastal ridge and in Area B. When the control




REPORT OF INVESTIGATIONS NO. 24 31
structure was open, approximately 45 percent of the flow through the control structure was contributed by Area B.
Ground-water hydraulic studies conducted by aquifer test methods and by tidal fluctuation methods indicate coefficients of transmissibility ranging from about 2.5 mgd per foot within the coastal ridge to more than 5.0 mgd per foot in Area B. The difference in transmissibility is caused by the presence of greater quantities of sand in the thick section of the aquifer underlying the coastal ridge, whereas, in Area B the aquifer is composed entirely of solution-riddled limestone.
Because of the excellent interconnection between the canal and the permeable aquifer in Area B, future well fields withdrawing as much as 200 mgd are planned by Metropolitan Dade County in the western part of the Snake Creek Canal area. These proposed fields would be important because withdrawals would be largely derived from Snake Creek Canal during dry periods and they would greatly exceed the present losses from the canal. The continuing changes in water control and withdrawals for water supply will alter the flow within the system and greatly increase the quantity of water required to maintain the desired levels in Snake Creek Canal. This study was limited in scope to the conditions existing at this time. However, the data presented will provide a basis for the analysis of the effects of major changes in the flow system and of the quantity of water needed in the future.







REPORT OF INVESTIGATIONS No. 24 33
SELECTED REFERENCES
Cooper, H. H., Jr.
Type curves for nonsteady radial flow in an infinite leaky aquifer:
U. S. Geol. Survey Water-Supply Paper (in press). Ferris, J. G.
1952 Cyclic fluctuations of water level as a basis for determining
aquifer transmissibility: U. S. Geol. Survey open-file report. Feulner, A. J.
1961 Cyclic-fluctuation methods for determining permeability as applied
to valley-train deposits in the Mad River valley in Champaign
County, Ohio: Ohio Jour. Sci., v. 61, no. 2, p. 99-106. Hantush, M. C.
1956 Analysis of data from pumping tests in leaky aquifers: Am.
Geophys. Union Trans., v. 37, no. 6, p. 702-714. Klein, Howard
1961 (and Sherwood, C. B.) Hydrologic conditions in the vicinity of
Levee 30, northern Dade County, Florida: Florida Geol. Survey
Rept. Inv. 24, pt. I.
Parker, G. G.
1951 Geologic and hydrologic factors in the perennial yield of the
Biscayne aquifer: Am. Water Works Assoc. Jour., v. 43, p. 817834.
1955 (and others) Water resources of southeastern Florida, with
special reference to geology and ground water of the Miami area:
U. S. Geol. Water-Supply Paper 1255. Schroeder, M. C.
1958 (and others) Biscayne aquifer of Dade and Broward counties,
Florida: Florida Geol. Survey Rept. Inv. 17. Sherwood, C. B. (see Klein, Howard) Stallman, R. W.
1956 Preliminary findings on ground-water conditions relative to Area
B flood-control plans, Miami, Florida: U. S. Geol. Survey openfile report.
U.S. Army Corps of Engineers
1954 Design memorandum, Hydrology and hydraulic design canals in
Greater Miami area (C-2 through C-9) (revised): Partial Definite Project Report, Central and Southern Florida Project, pt. 5, supp.
12, mimeograph rept., March 23.




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STATE OF FLORIDA STATE BOARD OF CONSERVATION DIVISION OF GEOLOGY FLORIDA GEOLOGICAL SURVEY Robert O. Vernon, Director REPORT OF INVESTIGATIONS NO. 24 PART III HYDROLOGIC STUDIES IN THE SNAKE CREEK CANAL AREA, DADE COUNTY, FLORIDA BY C. B. SHERWOOD AND S. D. LEACH U. S. GEOLOGICAL SURVEY Prepared by the UNITED STATES GEOLOGICAL SURVEY in cooperation with the CENTRAL AND SOUTHERN FLORIDA FLOOD CONTROL DISTRICT Tallahassee 1963

PAGE 2

FLORIDA STATE BOARD OF CONSERVATION FARRIS BRYANT Governor TOM ADAMS J. EDWIN LARSON Secretary of State Treasurer THOMAS D. BAILEY RICHARD ERWIN Superintendent of Public Instruction Attorney General RAY E. GREEN DOYLE CONNER Comptroller Commissioner of Agriculture W. RANDOLPH HODGES Director ii

PAGE 3

LETTER OF TRANSMITTAL §Lorida ceoloqical Survey &Callakassee February 18, 1963 Dear Governor Bryant: The Division of Geology is publishing as Part III of Report of Investigations No. 24; a report entitled, "Hydrologic Studies in the Snake Creek Canal Area, Dade County, Florida," prepared by C. B. Sherwood and S. D. Leach of the U. S. Geological Survey. The study was made as a part of the cooperative program of water studies between the Division of Geology and the Central and Southern Florida Flood Control District. This is a part of a series of short papers recording the hydrology and geology of several areas in the District. An attempt has been made to relate the characteristics of the water resources existing before the construction of control structures in the District to the attitude of those resources after the control structures have been made operative. These studies will be helpful to the District in managing the water resources, controlling the loss of water and in further design planning. Robert O. Vernon, Director and State Geologist iii

PAGE 4

Completed manuscript received January 24, 1963 Published for the Florida Geological Survey By E. O. Painter Printing Company DeLand, Florida Tallahassee, Florida 1963 iv

PAGE 5

TABLE OF CONTENTS Abstract _ _., _ ____._..____ 1 Introduction ____ 1 Acknowledgments ____-______ 3 Previous investigations _ --------3 Area of investigation ------4 Climate 4_ _~__ -____ 4 Topography and drainage -___4 Geology 7 Method of investigation _____ 7 Collection of data -_10 Analysis of data --__------13 Change in storage and flow _____ 13 Aquifer coefficients __----------26 26 Summary .__ 30 References -_________-_-----____ _____ 33 ILLUSTRATIONS Figure Page 1 Greater Miami area showing major hydrologic features and the area investigated ----------_ ____ 2 2 Greater Miami area showing the configuration of the natural drainageways and the coastal ridge -5 3 Photographs of salinity control structure near mouth of Snake Creek Canal _ 6 4 Geologic section along Snake Creek Canal (adapted from U.S. Corps of Engineers 1954, pl. 94) ___ 8 5 Geologic section along line A-A' near Snake Creek Canal 9 6 Graphs of water levels at six selected wells and two canal stations, discharge near the control structure, control openings, and rainfall in the Snake Creek area for the period July 1960 to April 1961 __ __ ___ _ 11 7' Stage and discharge of Snake Creek Canal at selected stations on March 25-26, 1961, when-the control was closed _ _ 12 8 Hydrographs of stage and-discharge at selected canal stations during test March 27-30, 1961 _ _14 9 Hydrographs of stage and discharge at selected canal stations during flushing operation March 31 to April 1, 1961 --15 10 Hydrographs of selected wells and canal stations March 25 to April 3, 1961 --____16 11 Diagram of tidal backwater in a canal and progressive changes of slope, directions of flow, and changes in storage of a tidal canal (Parker and others, 1955, fig. 127)-18 12 Snake Creek Canal showing mean flow regime, March 25-26, 1961 19 V

PAGE 6

ILLUSTRATIONS (Continued) 13 Vertical velocity profiles in midchannel for Snake Creek Canal at West Dixie Highway on March 29, 1961 20 14 Snake Creek Canal area showing contours on the water table, March 27, 1961 21 15 Snake Creek Canal showing average flow regime and water level profile during March 27-30, 1961 _ 22 16 Snake Creek Canal showing maximum and minimum discharge regimes and water-level profiles during March 27-30, 1961 __ 23 17 Snake Creek Canal area showing contours on the water table, March 29, 1961 25 18 Sketch showing selected wells in the Sunny Isles well field and graphs and graphs showing drawdown in water levels under various 18 Sketch showing selected wells in the Sunny Isles well field pumping conditions _27 19 Graphs showing relation between tidal fluctuations in Snake Creek Canal and selected wells _ 29 vi

PAGE 7

HYDROLOGIC STUDIES IN THE SNAKE CREEK CANAL AREA, DADE COUNTY, FLORIDA By S. D. Leach and C. B. Sherwood ABSTRACT Snake Creek Canal was constructed primarily to drain parts of northern Dade County and southern Broward County, Florida. During dry periods, however, it conveys water from the Everglades seaward to replenish coastal sections of the Biscayne aquifer. A salinity-control structure at the mouth of the canal prevents the upstream movement of salt water and helps to maintain upstream water levels high enough to prevent salt-water encroachment into the aquifer. These hydraulic effects are made possible because of the high permeability of the aquifer and the excellent interconnection between the canal and the aquifer. Hydrologic tests made March 25-26, 1961, on the flow system indicate that an inflow of 36 cfs (cubic feet per second) from Area B was required in the canal to maintain a water level of 2.7 feet above msl (mean sea level) at the control structure. This water is used to recharge the aquifer in the coastal ridge. Future well fields of Metropolitan Dade County will withdraw as much as 200 mgd (million gallons per day) from the Biscayne aquifer in the western part of the Snake Creek Canal area. These large quantities of water will be derived chiefly by infiltration from the canal system and will greatly increase the amount of water needed to maintain desired levels near the coast. During drought periods this quantity could amount to more than four times the natural losses from the system. INTRODUCTION This study is one of a series of hydrologic studies of canal area made in cooperation with the Central and Southern Florida Flood Control District to provide data for use in formulating an overall water-control plan for southeastern Florida. The rapid growth of population in the Greater Miami area has indicated a need to extend the existing water-control system to include a large swampy area of anticipated urbanization, designated as Area B, west of the -... .1 ...

PAGE 8

2 FLORIDA GEOLOGICAL SURVEY city (fig. 1). However, an urbanization plan for Area B must also be designed to prevent flooding within the area, and to maintain careful water control in the coastal area to prevent flooding and salt-water encroachment. SOUTH E RIVER CANAL .E.. O............. ..L..... --HO YWOOD B,^RO : 0 B AR REA A -:I REPORT A AREA A ' *"»'^-': .... .-. EXPLANATION E ] SCALE IN MILESr REPORT AREA ( AREA B C) CONTROL STRUCTURES \ \ " EXISTING I l C SCALE IN MILES UNDER CONSTRUCTION o I 2 3 4 s 6 Fig. 1. Greater Miami area showing major hydrologic features and the area investigated.

PAGE 9

REPORT OF INVESTIGATIONS NO. 24 3 The purpose of this study was to obtain a detailed description of the hydrologic environment in the Snake Creek Canal area and to provide quantitative definition of the following hydrologic factors: 1. The quantity of water needed to maintain a given bead near the coast, for the control of salt-water encroachment. 2. The discharge rates at selected points in the canal system under various controlled conditions. 3. Relation between ground-water movement and canal flow in different canal reaches. The investigation was made in 1961 by personnel of the Water Resources Division of the U. S. Geological Survey under the general supervision of A. 0. Patterson, district engineer, Surface Water Branch, Ocala, and M. I. Rorabaugh, district engineer, Ground Water Branch, Tallahassee. It was under the immediate supervision of J. H. Hartwell, engineer-in-charge, Surface Water Branch, Miami, and Howard Klein, geologist-in-charge, Ground Water Branch, Miami. ACKNOWLEDGMENTS The writers are indebted to the Central and Southern Florida Flood Control District, for furnishing complete information on their installations in the study area, and for operating control structure 29 during the test. Appreciation is expressed to the Dade County Public Works Department for information on the watercontrol system in the area, and the City of North Miami Beach for providing the equipment for aquifer tests and records of pumpage from their municipal well field. PREVIOUS INVESTIGATIONS A brief paper by Parker (1951) discusses the geologic and hydrologic factors in the perennial yield of the Biscayne aquifer in southeastern Florida, and a later report by Parker and others (1955) presents a comprehensive account of the geology and water resources of southeastern Florida. Schroeder and others (1958) summarize the hydrology and geology of the Biscayne aquifer and evaluate the perennial yield of the aquifer from data obtained since 1950. Stallman (1956) gives the results of electrical analog studies of the hydrology of intercanal areas of Dade County. Klein and Sherwood (1961) describe hydrologic conditions in the vicinity of Levee 30, which is southwest of the Snake Creek Canal area.

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4 FLORIDA GEOLOGICAL SURVEY AREA OF INVESTIGATION The Snake Creek Canal area is in the northernmost part of the Greater Miami area, Dade County, Florida. The area investigated extends about 21/2 miles north and 21/ miles south of Snake Creek Canal from Biscayne Bay to the eastern edge of Area B (fig. 1), a distance of about 11 miles. Supplemental water-level data were collected in the northern part of Area B. CLIMATE The climate in the Miami area is subtropical. Rainfall averages approximately 60 inches per year, about 75 percent of which occurs during the period May through October. This wet period includes both the normal rainy season and the hurricane season. The average annual temperature is approximately 750F. TOPOGRAPHY AND DRAINAGE The dominant topographic features of the area are the coastal ridge and the natural drainageways or transverse glades which cut through the coastal ridge from the Everglades. The configuration of the ridge and the drainageways is shown in figure 2. The land surface ranges from 5 to 7 feet above msl at the eastern edge of the Everglades and along the transverse glades, and from 9 to 20 feet above msl on the coastal ridge. Snake Creek Canal, the main drainage features of the area, flows eastward from Levee 33 to Biscayne Bay (fig. 1). The canal is the primary drainage channel for a large part of Area B, as well as for the northern part of the Miami area. Several secondary canals in the western part of Area A drain to Snake Creek Canal. South New River Canal in Broward County and Snake Creek Canal are connected by a north-south canal along the eastern edge of Area B (fig. 1). Flow in the canal system is maintained chiefly by ground-water discharge. During periods of heavy rainfall, considerable surface drainage is collected from low areas on the coastal ridge and from Area B. The flow in Snake Creek Canal is regulated by the operation of a control structure (fig. 3), about 11/4 miles upstream from Biscayne Bay. Submerged sluice gates in the structure are manipulated to provide maximum discharge for flood protection during periods of heavy rainfall and to prevent salt-water encroachment into the aquifer and into the upper reaches of the canal during dry periods.

PAGE 11

REPORT OF INVESTIGATIONS NO. 24 5 SOUTH NEW RIVER CANA BROWARD COUNTY CREEK CANAL DADE COUNTY Ný., EXPLANATION COASTAL RIDGE Fig IGLADE LINE SCALE IN MILES Fig. 2. Greater Miami area showing the configuration of the natural drainageways and the coastal ridge.

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6 FLORIDA GEOLOGICAL SURVEY Fig. 3. Photographs of salinity-control structure near mouth of Snake Creek Canal.

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REPORT OF INVESTIGATIONS NO. 24 7 GEOLOGY The area crossed by the Snake Creek Canal is underlain by the permeable limestone, sandstone, and sand of the Biscayne aquifer. The aquifer underlies the land surface to a depth of about 200 feet near the coast and to about 55 feet at the western end of the Snake Creek Canal. The aquifer is predominantly limestone at the coastline and in Area B, but it varies sharply between limestone and sand throughout most of the coastal ridge. The changes in the shallow, subsurface materials are shown in the geologic section in figure 4. The section also indicates that low areas along the natural drainageways are covered by several feet of muck or organic material. The nature of the deeper materials within the aquifer is shown in the west-east geologic section, along Snake Creek Canal, figure 5. In general, the most permeable zones occur in the lower part of the aquifer. Supply wells in the Sunny Isles and Norwood well fields, operated by the City of North Miami Beach (fig. 14), tap highly permeable limestones at depths ranging from 60 to 120 feet below the land surface. Individual wells in these well fields yield as much as 2,000 gpm (gallons per minute) with a water-level drawdown of approximately 6 feet. Combined pumpage from the two well fields during 1960 ranged from 5.4 to 14.6 mgd. METHOD OF INVESTIGATION Hydrologic tests of the Snake Creek Canal area flow system were made during the period March 25 to April 1, 1960. The control was closed March 25-26 and the water level was held in equilibrium at a high stage of 2.7 feet. Measurements were made during this condition at several points along the canal to determine the flow required to maintain the head existing at the control structure. The structure was opened on March .27 and then closed on March 30 to induce abrupt changes in area-wide water-level conditions. On March 31, the control was opened for 41/½ hours to flush out salt water that was trapped upstream from the control structure during the test. Observations and analyses were made of the changes in water levels and flow that resulted from the operation of the control structure. Data collected during previous investigations and during a continuing observational program were used to supplement the test data.

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8 FLORIDA GEOLOGICAL SURVEY ALTITUDE.IN FEET, REFERRED TO MSL -LEV"EE 33 U.SHWY H7 i RED ROADO RED ROAD DOUGLAS ROAD S" DOUGLAS ROAD -----STA-ROAD 7 -------! S---STATE ROAD 7 ONTRO CONTROLE AY Fig. 4. Geologic section along Snake Creek Canal. (Adapted from U. S. Corps of Engineers1954pL94YK -

PAGE 15

-REPORT OF INVESTIGATIONS No24 9 _ , '? o o o o o o , 0 5 0 5 0 a "XtH 31XI GL .IS. 6 011 3AIUI Q. SN30aV9 1NVIW! 0 00 0 w > rd m 0 0 0 r!SI0 <'1 o 7 -7 V0 0 0 V c -0O .01 1 0ii -C"D rnri>-, i " 73A37. V3l.NV3 01S 3 .-'3J 233, NI '30'/.I117V .... ____________ z i 'O o tsii oi& ID o~ ~-l~ 1 2 "'~1-·c-

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10 FLORIDA GEOLOGICAL SURVEY Discharges at selected points in the canal were computed during the test periods from stage-area and deflection-mean velocity relationships. Current-meter measurements were made by conventional methods and, from these measurements, the crosssectional area and the mean velocity of the canal were determined under various conditions. Continuous stage records were obtained from water-stage recorders, and continuous records of an index of velocity were obtained from deflection meters installed at midchannel. A deflection meter consists of an underwater vane attached to a vertical shaft that is free to rotate. The amount of angular rotation caused by the force of the flowing water is recorded in deflection units on a chart. Discharge was thus computed from the basic formula Q = AV, in which Q is the discharge, in cubic feet per second A is the cross-section area of the canal, in square feet, from the stage-area relationship V is the mean velocity of flow, in feet per second, from the deflection-mean velocity relationship. COLLECTION OF DATA The continuing water-records program in the area includes 22 observation wells, a water-level recording station in Snake Creek Canal at Red Road, and a water-level and discharge measuring station in the canal at West Dixie Highway (fig. 14). Six of the observation wells are equipped with water-level recording gages. Records from these data-collection stations provided considerable background data on the fluctuation of water levels throughout the drainage area. For use during the test period, 28 additional shallow observation wells were drilled. Water-level recorders were installed on three of these wells and on seven privately owned wells. Two portable deflection meters and four water-level recorders were installed in the canal, and a water-level recorder was installed near the mouth of the Oleta River. All observation points were referred to mean sea level datum by spirit level. The locations of all datacollection sites are shown in figure 14. Water-level fluctuations in six selected wells and at two canal stations, discharge of the canal near the control structure, and rainfall measured at Douglas Road are shown for the period July 1960 to April 1961 in figure 6. The effects of control operations during the test period, March 25 to April 1, 1961 are shown by sharp fluctuations of discharge and water levels.

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REPORT OF INVESTIGATIONS No. 24 11 1960 1961 JULY AUG. SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR. 1OO 1020 1020 o " 1020 1 0 20 1020 W0 2 WELL 672 -CANAL EXTENSION COMPLETED Y. WELL G6LI DAILY HIGH _AWELL G970 Id > .I i.-. .'7 LL 4 3 [ r,' ;WELL G851 iS I INAKE RKALHI SJ, , .1 .TEDOA 1d '{ *^WELLGBO D 4oc _ _i· RERD" I -I 1 L SNNAKE CREEK CANAL S U AT REDROAD SSAEE CREEK CANAL A W DIXIE HWI DAILY MEAN SNAKE CRESK CANAL S I .M ATW.DIXIEHWY 0 o2000 ---___ -____ -_--------------LL 00 01200 -discharge near thecontrol -stru€tre, control opening, and rainfal in the Snake reekareaorhe odJul1960 to ATUSril 1961 SNAKE CREEK CANAL SATDOUGLAS ROAD zzIL < 1W L-----__ ___ ___Fig. 6. Graphs of water levels at six selected wells and two canal stations, discharge near the control structure, control opening, and rainfall in the Snake Creek area for the peiod July 1960 to April 1961.

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12 FLORIDA GEOLOGICAL SURVEY On March 25 and 26, observations were made throughout the test area to determine the magnitude and direction of flow required to maintain a constant water level of 2.7 feet above msl at the control structure. Stage and discharge of Snake Creek Canal at selected stations during this period are shown in figure 7. MARCH 25 1961 MARCH 26 6:-00 120 ' 600 12.00 6 1-'00 6:00 o SNAKE CREEK CANAL a 6_----_ T RED ROAD--6-T RED R-AD -SNAKE CREEK CANAL u ... \ ..mT MIAMI GARDENS DRIVE o4C ........... ....................... u p-,SNAKE CREEK CANAL C AT W DIXIE HWY -4 SNAKE CREEK CANAL rAT RED ROAD o"_______ ----r----'-=r -~ ------0 ----j~ATW.IXI~nW--C 3 -------------------2.--1 -__ __ _ __ . SNAKE CREEK CANAL A W DIXIE HWY SNAKE CREEK CANAL ~ -" """'~""` "" '*;^ .... _ _ A T DOUGLAS ROAD >SNA KE CREEK NA L/^LZ"1-"u. AT M/AMI GARDENS DRIVE Fig. 7. Stage and discharge of Snake Creek Canal at selected stations on March 25-26, 1961, when the control was closed. After the four bays of the control structure were opened at 10:15 a.m. on March 27, water-level fluctuations were measured in the observation wells, and continuous records of stage and streamflow were collected in Snake Creek Canal at West Dixie Highway, at Miami Gardens Drive, and at Red Road. The discharges measured on March 28 at the three stations along the canal during a tide cycle and near the time of opening (10:15 a.m. March 27) and closing (9:00 a.m. March 30) the control dam are shown in the following tabulation:

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REPORT OF INVESTIGATIONS NO. 24 13 Red Road Douglas Road -Miami Gardens Drive March 27 Discharge Discharge Discharge Time (cfs) Time (cfs) Time (cfs) 12:10 p.m. 639 11:00 a.m. 637 2:40 p.m. 706 12:10 p.m. 1,010 12:20 p.m. 2,310 1:35 p.m. 1,010 2:55 p.m. 960 March 28 9:50 a.m. 333 8:05 a.m. 240 8:40 a.m. 189 12:05 p.m. 496 10:30 a.m. 516 10:35 a.m. 1,130 1:45 p.m. 550 1:30 p.m. 780 11:40 a.m 1,340 3:50 p.m. 613 4:35 p.m. 734 1:40 p.m. 1,550 March 30 9:25 a.m. 154 7:50 a.m. -421 11:25 a.m. 244 (indicated flow upstream) Fluctuations of stage and discharge at four canal stations during the test period are shown in figures 8 and 9. Fluctuation of-levels in selected wells and canal stations during the period March 25 and April 4 are shown in figure 10. Starting near low tide at 1:30 p.m. on March 31, a 41/2-hour flushing operation was conducted to remove the salt water that was trapped in the canal upstream from the salinity-control structure. This flushing operation was scheduled as part of the test because its effects are similar to those caused by normal operating procedures for removing debris from the canal. The abrupt changes in water level and discharge caused by this operation are shown in figure 9. The additional rise in water level and discharge during the morning of April 1 was caused by heavy rainfall in Area B. ANALYSIS OF DATA CHANGE IN STORAGE AND FLOW Changes in storage and flow within the system depend chiefly upon: (1) the quantity of rainfall recharging the system, (2) the quantity of inflow from the Everglades by canals and by underflow, (3) operation of the control structure, and (4) tidal backwater in the canal. The correlation of these factors is shown by the hydrographs in figure 6. Each heavy rainfall caused a corresponding rise of the water table and the canal stage, except in the lower reaches of the canal where levels generally are regulated by the control

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14 FLORIDA GEOLOGICAL SURVEY MRRC M 28 MARCH 29 MARCH 30 I 'I AIMW AR CCT O eR ,I M 1 i G5_0 nd .... .. ... _ _ K Fig. 8. Hydrographs of stage and discharge at selected canal stations during S test March 27-30, 196 structure During long periods of heavy rainfall, ground-water levels rise to 4 or 5 feeE t above msl in areas near the coast (wells i850 and D151). Wfater levels in areas near the coast decline rapidly as the rainfall decreases, but in upgradient areas the is opened, large quantities of water from the west drain into the canal system and the aquifer. The control structure is kept open for long periods to discharge this excess water. The extension of Snake Creek Canal to the western edge of Area B, during October

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REPORT OF INVESTIGATIONS NO. 24 15 MARCH 31 1961 APRIL I 6:00 -200 6-00 12.00 600 12:00 6 200C SNAKE CREEK CANAL 6 AT W. DIXE HWY 160C 00 U) 42 (3 I R R AT RED ROAD " .i I S E IA / CD 400 ATATU RED SOROAD SSNA KE CREEK SNAE -2 -=S E C w Fig. 9.; Hydrogrdphs of stage and discharge at selected canal stations during flushing operationi March 31 to April 1, 1961. w .. .-_-E .CREEK CANAL flushing operation Mdarch 31 to April 1, 1961.

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16 FLORIDA GEOLOGICAL SURVEY MARCH 1961 APRIL 25 26 27 28 29 30 3 I 2 3 -WELL 6970 30 3.0 ___ __ -; -CANAL S(3.5 Mi. EAST OF WELL /1053WEST END) WELL GI045-WE OLETA RIVER-' .0 -i LELL 66/5 TE WELWELL SF 2.( I --^ nFig. 10 Hydrographs of selected wells and canal stations March 25 to April 3, 1961. gag 2.5 L --6^ 6/ ^ --__ __ __ 3, 1961.

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REPORT OF INVESTIGATIONS NO. 24 17 1960, had a marked effect on water levels in that area as shown by wells G72 and G970 in figure 6. The water level in well G72 near the western end of the canal declined sharply when the canal was completed on October 28, 1960, and by the end of February 1961, had declined to less than 4.0 feet above msl. The gradient between well G72 and the control structure at this time was less than 1.5 feet in 17 miles, or 0.09 foot per mile. As the canal has been extended, higher flood discharges through the control structure will probably occur; however, the duration of high discharge should be shorter because of the more rapid drainage of Area B. When the control structure is open, a large part of the system is affected by tides. The magnitude of the effect decreases upstream and depends upon the amount of the gate openings and the rate of discharge. Tidal fluctuations of 0.3 of a foot were observed at the western end of the canal during the test; however, when the control was open during flood periods prior to the test very little fluctuation occurred in the canal west of Red Road. Maximum discharge from the canal occurs 1 to 2 hours before low tide, and minimum discharge occurs at high tide (fig. 8). Figure 11, from Parker and others (1955, fig. 127), shows progressive changes of slope of the water surface, direction of flow, and changes in storage in a tidal canal. The changes in flow and stage caused by opening or closing the control structure during the test correspond generally with the changes caused by a falling or rising tide, except for rate and magnitude. The extent of area affected within the flow system depends chiefly on the length of time the control structure remains open or closed, and the antecedent hydrologic conditions. The hydrographs in figure 10 indicate that a period of several days is required for water levels throughout the area to adjust fully when the control is open or closed. The hydrographs also show the effects of the difference in permeability between the sandy materials in the coastal ridge and the limestones underlying Area B. The water level in well G970, half a mile south of the canal and 15 miles inland, responds more readily to changes in canal stage than the water level in wells G1052 and S1442 which are closer to the canal within the coastal ridge. The hydrographs in figure 7 show the canal discharges on March 25-26 when an average water level of 2.7 feet above msl was maintained at the closed control structure. A strong easterly wind was the chief factor contributing to variation of discharges. The

PAGE 24

18 FLORIDA GEOLOGICAL SURVEY D/ ,4 L 0 C A *° ^5 ----^COhVI70M N r MO rv r 2t <-rr iIt '~~~n rrn_¢¢'v W, SEA ^^^: * ^^^'--« i RMLY sl! dieto of/ flow,-an chage in strg fatdl >aa Pren othe 0 rWfgrA7 S'r '^ 4U:t<^ f*(D 4.~ ii SYW. FALLOW '^' F*, ILT ~_^ WBrO qe Flew AEFVW Low8 _ _ ~ ~ _ I.I AVANUTX LEMC' ET -->, ~ mfau ourrnsi ° ^&a EXPAaaM C^^A v ---w OU I>Ls ie-s u =»»aacn Aoroe DOCCTCM a iu r FLOW-r~ OWIPt OF OHL 1nyTOUc-LOSM: Fig11Diagram of tidal backwater in -a canal and progressive changes of slope, direction of flow, -and changes in storage of a tidal canal (Parker and others, 1955, figure 127).

PAGE 25

REPORT OF INVESTIGATIONS No. 24 19 mean discharges at Red Road, Miami Gardens Drive, and West Dixie Highway for this period are shown schematically in figure 12. These discharges were 36, 32, and 16 cfs, respectively. The discharge of 36 cfs at Red Road represents the inflow required from Area B on March 25-26 to maintain the water level at 2.7 feet at the control. The measurements indicate that seepage from the canal to the aquifer increases rapidly in the reach between Miami Gardens Drive and the control structure. EXPLANATION I S N DIRECTIONO F FLOWAND DISCHARGE.CFS OUTFLOW I'CANAL REACH,CFS S INFLOW IN CANAL REACH,CFS P,'**Q.E E'SE IN CHANNEL STORAGE Fig. 12. Map of Snake Creek Canal showing mean flow regime, March 25-26. 1961. The hydrographs in figure 8 give a comprehensive picture of the fluctuations of water levels and discharges in the flow system during the test period of March 27-30 when all four gates of the control structure were open. The gates were opened at 10:15 a.m. on March 27, at low tide, to induce the maximum possible change in water level and flow throughout the test area. The control structure was left open, as long as it was feasible to do so, to establish relatively stable drainage conditions within the flow system. The length of the period was limited by the rapid intrusion of salt water up the canal. The discharge at West Dixie Highway during each tide cycle on March 27-30, is shown in figure 8. The anomaly in the discharge graph at West Dixie Highway immediately preceding a tidal peak discharge, is probably related to the upstream movement of the salt-water wedge in the lower reach of the canal. The effect of this wedge on discharge is strikingly shown in figure 13 by the velocity profiles in a vertical section at midchannel of the canal. The sharp oscillations in flow and water level (fig. 8, 9) were caused by the abrupt closingi of the control. The configuration of the. water table on March 27 under relatively unchanging conditions before the opening of the control

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20 FLORIDA GEOLOGICAL SURVEY 9:15 A.M. 0.1 ft/sec 2--9 4A.M. 1.12 ft/sec 12:20P. M. 1.39 ft/sc S C 2: P.M. .67 ft/sec U1 Q z , IN F T TIME MEAN VELOCITY 8:18 A.M. -0.15 ft/sec 2 ---9:15 A.M. .12 ft/sec 10:03 A.M. .66 ft/sec 10:54A.M. 1.12 ft/sec 12:20 P.M. 1.39 ft/sec 0 CANAL BED ___ __ 2:35 P.M. 1.67 ft/sec -[--UPSTREAM -&0*-DOWNSTREAM--I 2 VELOCITY, IN FEET PER SECOND Fig. 13. Vertical velocity profiles in midchannel for Snake Creek Canal at West Dixie Highway on March 29, 1961. structure, is shown by the contour map in figure 14. The groundwater gradients (fig. 14) and the canal discharges (fig. 12) on March 25-26, when the control structure was closed, indicate that water was entering the aquifer from the canal in all reaches east of Red Road. A comparison of the hydrographs of well G970 and the adjacent canal station in figure 10, shows the ground-water gradient in Area B to be toward the canal at this time. When the control structure is closed, the ground-water gradients are steepest and the seepage from the canal is greatest near the coast and

PAGE 27

...---a ....... . S01067 3/ C I ' I N, SIO 2 1 AS 0 100 1 M 10"RA. I L/ IXKLANATION, BS t F i. :..1.. "ee C "rea -\ o u on the wae b M WATIRlrTBLM CONTOU INfH T FIT ,, , , l' " ',1 0S»l0.D WHeI6 INfERRED --oS-o FlELD at t ST Ff/ / i t6 . DEFLEOTION METER z WAT(R*lEt(I RCO1R0DING OP1O J ! g | 1 I. 1 I INSVAO t N W IL S Ii. Fig. 14. Snake Creek Canal area showing contours on the water table, March 27, 1961. STAF OA0 r IGS5

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22 FLORIDA GEOLOGICAL SURVEY through the area of limestone quarries between the canal and the Oleta River. In these areas the shallow materials are highly permeable. As shown in figure 14 ground-water gradients south of the Snake Creek Canal are reduced by the effects of the controlled reach of the Biscayne Canal except in the area near the coast; north of the Snake Creek Canal the water table slopes northeastward toward the coast and toward the uncontrolled reach of South New River Canal in Broward County (fig. 1). The secondary canals which connect Snake Creek Canal to the major canals of the regional water-control system (fig. 1) are highly constricted in many places and convey very little water, except during flood periods. Thus, it is evident that most of the water that enters the canal during extended dry periods is derived from ground-water storage in the western part of the coastal ridge (fig. 2) and in Area B. The average flows and water levels which occurred when the control structure was open are shown in figure 15. The magnitude and direction of flow at any time can be obtained from the hydrographs in figure 8. The maximum and minimum discharges and water levels in the canal during this period are shown in figure 16. EXPLANATION 3.Wz -ND DISCNRGE.C FS *-.FNLOW IN AC L REACH.CFS € I ECREASE I C-%NELSTORAGE rofiles durin MaL REch 27-30CFS 191. 4-4 Fig. 15. Snake Creek Canal showing average flow regime and water-level profiles during March 27-30, 1961.

PAGE 29

REPORT OF INVESTIGATIONS NO. 24 23 SEXPLANATION MR DIECTION OFFLOW UND DOSCIIRGE.NFS M AXIMUM DISCHURGEU MINIMUM DISCHSRGE Q t , the test period. The surface area changes very little with changes Q~ in stage because thCreek Canaside slope of these canalsmaximum and rockminimum dischare steep. The tabulation below includes the area of Snake Creek Canal and the connecting secondary canals and rock pits. Surface area, Canal reach (square feet) Control structure to West Dixie Highway ..------. .....171,000 West Dixie Highway to Miami Gardens Drive _ ... 1,280,000 Miami Gardens Drive to Douglas Road -_-____ -_ 9,872,000 Douglas Road to Red Road ________ ____ 8,238,000 Red Road to U. S. Highway 27 -_ 3,485,000 The rate of change in canal storage was computed by the Ad formula Q.= , where QC is the discharge from storage, in cfs, A is the water-surface area in square feet, d is the average decline in water level, in feet, (static level at opening of control to mean tide level at closing), and t is the time in seconds of the period under consideration. The computations for the average discharge the tetpro.Tesraeae hagsvr itewt hne insaebcuetesd2lp fteecnl n okpt r ste.TetbltoIeonncue h rao nk re Caanz h oncigscodr aasadrc is

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24 FLORIDA GEOLOGICAL SURVEY from storage in the canal reach between the gaging stations for the period March 27-30 are, as follows: West Dixie Highway to Miami Gardens Drive: S Ad _ 1,280,000 x 2.17 11 cfs t 254,700 Miami Gardens Drive to Douglas Road: -9872,000 x 2.00 -78 cfs 254,700 Douglas Road to Red Road: Q8,238,000 x 1.82 = 59 cfs 254,700 Red Road to U.S. Highway 27: S3,485,000 x 1.52 = 21 cfs 254,700 The mean discharges for the test period March 27-30 at West Dixie Highway, Miami Gardens Drive, Douglas Road, and Red Road were 1,011, 832,625, and 445 CFS, respectively, as shown in figure 15. The discharge at Red Road, 445 cfs, was the average inflow from the Everglades and Area B. The average ground-water inflow along reaches between the canal discharge stations was computed by the following formula: Qc = Q, -Q2 -Q,, where Q, is the inflow from the aquifer, in cfs, Q, is the discharge at the downstream station, in cfs, Q2 is the discharge at the upstream station, in cfs, and Q, is the discharge from (decrease in) the canal storage, in cfs, from a foregoing paragraph. The computations of the mean groundwater inflow in the canal reach between the gaging stations are shown in figure 15 and are as follows: West Dixie Highway to Miami Gardens Drive: Qg = Q1 -Q2 -Q. = 1,011 -832 -11 = 168 cfs Miami Gardens Drive to Douglas Road: Qg = Q1 -Q2 -Q. = 832 -625 -78 = 129 cfs Douglas Road to Red Road: Q = Q1 -Q2 -Q, = 625 -445 -59 = 121 cfs Red Road to U.S. Highway 27 Q, = Q -Q2 -Q = 445 -0 -21 = 424 cfs The configuration of the water table on March 29 before the closing of the control is shown in figure 17. The sharp decline of the water level in the canal after the opening of the control caused ground-water inflow to the canal in all

PAGE 31

, XPLANATION / WATE-TAILE ONTOUR IN T ABOV iA 1160Il SEA LEVELL DASHED WHERE INFRRED )' mog 4 EL *01161 1.5 STAFF AG r WATCI-LEVEL. MCORDING GAoE I l ' -., , , .. .8651B . -L --"S V, / o : b --lo 's 190 010 4-15 0 ..-.. 045 0410 T O EN I--, I ,, O 01050 Fig. 17. Snake Creek area showing contours on the water table, March 29, 1961. er

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26 FLORIDA GEOLOGICAL SURVEY reaches (fig. 10, 17). The hydrographs in figure 8 indicate that the discharge at each gaging station in the canal declined very slowly during the test period. This was because of the sustained inflow of ground water. However, if the control structure were left open for an extended period, ground-water storage would be depleted, and the discharge in the canal would decline steadily. AQUIFER COEFFICIENTS The principal hydraulic properties of an aquifer may be expressed as coefficients of transmissibility (T) and storage (S). The coefficient of transmissibility is defined as the amount of water, in gallons per day, at the prevailing temperature, transmitted through a 1-foot strip of saturated thickness of the aquifer under a hydraulic gradient of 1 foot per foot. The coefficient of storage is defined as the unit volume of water released from, or taken into, storage per unit surface area of aquifer per unit change in the component of head normal to that surface. Two short aquifer tests were conducted to define the aquifer coefficients in the vicinity of the Norwood and Sunny Isles well fields of the City of North Miami Beach. In addition, the approximate coefficient of transmissibility in several areas along the canal was computed by a method involving the cyclic fluctuation of ground-water levels caused by tides in the canal. The two aquifer tests were made by pumping selected municipal supply wells in the well fields (fig. 14) and observing the drawdown of water levels in nonpumping supply wells and in observation wells. The supply wells are developed in beds of highly permeable limestone that are overlain by 60 to 100 feet of less permeable sandy limestone and sand. The layout of the wells in the Sunny Isles well field and the drawdown of water level in selected wells during various pumping conditions are shown in figure 18. The drawdown data collected during the aquifer tests were adjusted to correct for fluctuations caused by factors other than pumping-chiefly, a steady rise in regional water levels caused by operation of the salinity controland were analyzed by use of a family of leaky aquifer-type curves developed by H. H. Cooper, Jr., U. S. Geological Survey, from a method outlined by Hantush (1956). This method provides a means to compute the values of the coefficients of transmissibility and storage of the producing zones, and the coefficient of leakage of the less permeable beds that overlie the producing zone. The coefficient of leakage may be

PAGE 33

REPORT OF INVESTIGATIONS No. 24 27 *Io0 3A RECORDING ! 8 GAGE 0 356 f --173 FtII 9:00 12:00 3:00 6:00 DISTANCE FROM PUMPED WELL,IN FEET A M. M P.M P M. 100 200 300 400 IW PUMP ON WELL NO.3-0 ------JUNE 9,1961 10 Z PUMPING WELL NO.11 4 O 800 GPM 0 PUMP OFF r -/ JUNE 9,1961 r 4x PUMPING WELL NO.11
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28 FLORIDA GEOLOGICAL SURVEY The configuration of the water table between the Sunny Isles well field and the canal in figure 14 indicates that water was flowing from the canal toward the well field at that time. During extended periods of drought and heavy pumping, a large part of the water withdrawn from this well field would be derived from the canal and, as a result, the drawdown in the well-field area would be minimized. Thus, the possibility of maintaining the well field, which is near the coast and close to the salt front in the aquifer, is largely dependent upon the effectiveness of the water-control system to maintain the canal level high enough to prevent further intrusion of salt water. The proximity of the salt front in the aquifer is indicated by the chloride content of more than 8,000 ppm (parts per million) in water samples collected at a depth of 57 feet below the land surface in well D151 (fig. 14). The tidal data collected from wells near the canal were analyzed by a method which relates the time lag and stage efficiency of the tidal fluctuations in the aquifer and the canal to the value of T/S for the aquifer (Ferris 1951). An approximate value for T was computed using values for S determined by the pumping test methods and by examination of well-log data. The equation relating the transmissibility of the aquifer to the ratio of the range of ground-water level fluctuation to the range of the tidal fluctuation in the canal can be simplified if the range ratio is plotted on a logarithmic scale against the distance from the suboutcrop to the observation well on an arithmetic scale. Then the equation may be written as follows: T 44.4 x S to T = coefficient of transmissibility, in gallons per day per foot S = coefficient of storage (dimensionless) t, = period of the stage fluctuation, in days x = distance with the observation well to the surface-water contact with the aquifer (suboutcrop), in feet x = change in x over one log cycle The equation relating the time lag between the occurrence of a given tidal peak or trough in a well and the corresponding state in the canal to the value of T/S for the aquifer can be written T = 0.6x2t0S Where ti is the lag in time, in days. t12 Tidal data from selected wells, and computations using both methods are shown in figure 19. In both cases the effective distance to the offshore outcrop is assumed to be half the canal width (60 feet). The error introduced by this assumption would be small

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REPORT OF INVESTIGATIONS NO. 24 29 because the width of the canal is small in comparison to the distance to the observation wells. In theory, however, the intercept of the line established by the plotted data with the line of zero time lag, or 100 percent stage efficiency, would indicate the distance from the shoreline to the outcrop. RANGE RAtIO -'tlAL-RAN,.-~GRUNbD-WAtEil0A N RA TIDAL RANGE, CANAL TIME LAG IN HOURS o. O .0m J4 .0... b5. 0 ..1 --11 .0 .4 1.. 0 1 1 2 z4 5 s \ &1440 -T= O.6OX T 1T-(I s 240G ---------T=6u1 5 s I .. _ .._ .i o00 --N 11 _____ ------f S=O. 142 T-3.4XIO GPD per Ft. 2 000 0 t 10 12 0 -1 .-"_ _ _ T= S \44 400 T=2.4xI0S ------.. If So.15 Gis 053 T .6Xlto u CI per Ft. XI _ _ _ _ _ _ _oA& t_ 13 HOURS Fig. 19. Graphs showing relation between tidal fluctuations in Snake Creek Canal and selected wells. Coefficients of transmissibility computed by these methods (fig. 19) were about 3.5 mgd per foot within the coastal ridge. This value is appreciably higher than those computed from aquifer test data (2.0 to 2.5 mgd per foot) and probably not as reliable, but provides a useful indication of the capacity of the aquifer, if no other data were available. Computations based on tidal data from well G970 in Area B, for example, indicate a coefficient of transmissibility of more than 5.0 mgd per foot. This value seems high for an area where the aquifer is only 75 feet thick (Schroeder,. 1958), but it is supported by both the known occurrence of highly permeable materials in that area and by studies of underflow along Levee 30 in the western edge of Area B where Klein and Sherwood (1961) indicate a coefficient of transmissibility of 3.6 mgd per foot where the aquifer is only 55 feet thick. The high permeability of the aquifer and excellent interconnection between the canal and the aquifer in Area B indicate that this reach of the Snake Creek Canal system would be a highly

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30 FLORIDA GEOLOGICAL SURVEY desirable area for the location of large future well fields. Withdrawals as high as 200 mgd are proposed from well fields of Metropolitan Dade County in the western part of the Snake Creek area by the year 2000. During dry periods these well fields will be largely dependent on recharge by induced infiltration from a network of secondary canals connected to Snake Creek Canal. SUMMARY The Snake Creek Canal drains the northern part of the Greater Miami area and is the main drainage canal for the northern part of Area B. Flow in the canal is maintained chiefly by the inflow of ground water, but considerable surface runoff is introduced from low areas on the coastal ridge and from Area B during flood periods. Canal discharge is regulated by a control structure near Biscayne Bay to provide maximum flood protection and to main maintain water levels high enough to retard salt-water encroachment during dry periods. The area crossed by the Snake Creek Canal is underlain by the highly permeable Biscayne aquifer, which extends from the surface to a depth of 200 feet at the coast and about 55 feet at the western end of the canal. Natural drainageways that connect Area B with Biscayne Bay are bottomed by several feet of material of relatively low permeability. Ground-water levels can be effectively raised or lowered throughout the drainage area by manipulation of the control structure. When the control structure is open, ground water flows toward the canal and the canal flow increases toward the bay. When the control structure is closed canal levels near the coast are generally higher than ground-water levels and appreciable groundwater recharge from the canal occurs. Information collected during a test on March 25-26, 1961, indicated that an inflow of 36 cfs from Area B was required to maintain a water level of 2.7 feet above msl near the coast when the control structure was closed. Ground-water gradients and canal discharges indicate the canal was recharging the aquifer throughout the system east of Red Road under these conditions. The secondary canals which connect Snake Creek Canal to other major canals of the regional water-control system are constructed in many places and convey very little water except during flood periods. Thus, most of the water entering the canal during extended dry periods is derived from ground-water storage in the western part of the coastal ridge and in Area B. When the control

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REPORT OF INVESTIGATIONS NO. 24 31 structure was open, approximately 45 percent of the flow through the control structure was contributed by Area B. Ground-water hydraulic studies conducted by aquifer test methods and by tidal fluctuation methods indicate coefficients of transmissibility ranging from about 2.5 mgd per foot within the coastal ridge to more than 5.0 mgd per foot in Area B. The difference in transmissibility is caused by the presence of greater quantities of sand in the thick section of the aquifer underlying the coastal ridge, whereas, in Area B the aquifer is composed entirely of solution-riddled limestone. Because of the excellent interconnection between the canal and the permeable aquifer in Area B, future well fields withdrawing as much as 200 mgd are planned by Metropolitan Dade County in the western part of the Snake Creek Canal area. These proposed fields would be important because withdrawals would be largely derived from Snake Creek Canal during dry periods and they would greatly exceed the present losses from the canal. The continuing changes in water control and withdrawals for water supply will alter the flow within the system and greatly increase the quantity of water required to maintain the desired levels in Snake Creek Canal. This study was limited in scope to the conditions existing at this time. However, the data presented will provide a basis for the analysis of the effects of major changes in the flow system and of the quantity of water needed in the future.

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REPORT OF INVESTIGATIONS No. 24 33 SELECTED REFERENCES Cooper, H. H., Jr. Type curves for nonsteady radial flow in an infinite leaky aquifer: U. S. Geol. Survey Water-Supply Paper (in press). Ferris, J. G. 1952 Cyclic fluctuations of water level as a basis for determining aquifer transmissibility: U. S. Geol. Survey open-file report. Feulner, A. J. 1961 Cyclic-fluctuation methods for determining permeability as applied to valley-train deposits in the Mad River valley in Champaign County, Ohio: Ohio Jour. Sci., v. 61, no. 2, p. 99-106. Hantush, M. C. 1956 Analysis of data from pumping tests in leaky aquifers: Am. Geophys. Union Trans., v. 37, no. 6, p. 702-714. Klein, Howard 1961 (and Sherwood, C. B.) Hydrologic conditions in the vicinity of Levee 30, northern Dade County, Florida: Florida Geol. Survey Rept. Inv. 24, pt. I. Parker, G. G. 1951 Geologic and hydrologic factors in the perennial yield of the Biscayne aquifer: Am. Water Works Assoc. Jour., v. 43, p. 817834. 1955 (and others) Water resources of southeastern Florida, with special reference to geology and ground water of the Miami area: U. S. Geol. Water-Supply Paper 1255. Schroeder, M. C. 1958 (and others) Biscayne aquifer of Dade and Broward counties, Florida: Florida Geol. Survey Rept. Inv. 17. Sherwood, C. B. (see Klein, Howard) Stallman, R. W. 1956 Preliminary findings on ground-water conditions relative to Area B flood-control plans, Miami, Florida: U. S. Geol. Survey openfile report. U.S. Army Corps of Engineers 1954 Design memorandum, Hydrology and hydraulic design canals in Greater Miami area (C-2 through C-9) (revised): Partial Definite Project Report, Central and Southern Florida Project, pt. 5, supp. 12, mimeograph rept., March 23.

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-FLORIDA-GEOLOGICAL-SURVEY COPYRIGHT NOTICE © [year of publication as printed] Florida Geological Survey [source text] The Florida Geological Survey holds all rights to the source text of this electronic resource on behalf of the State of Florida. The Florida Geological Survey shall be considered the copyright holder for the text of this publication. Under the Statutes of the State of Florida (FS 257.05; 257.105, and 377.075), the Florida Geologic Survey (Tallahassee, FL), publisher of the Florida Geologic Survey, as a division of state government, makes its documents public (i.e., published) and extends to the state's official agencies and libraries, including the University of Florida's Smathers Libraries, rights of reproduction. The Florida Geological Survey has made its publications available to the University of Florida, on behalf of the State University System of Florida, for the purpose of digitization and Internet distribution. The Florida Geological Survey reserves all rights to its publications. All uses, excluding those made under "fair use" provisions of U.S. copyright legislation (U.S. Code, Title 17, Section 107), are restricted. Contact the Florida Geological Survey for additional information and permissions.


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