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 Transmittal letter
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 Method of investigation
 Analysis of data
 Summary
 Selected references


FGS






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
Secretary of State




THOMAS D. BAILEY
Superintendent of Public Instruction




RAY E. GREEN
Comptroller


J. EDWIN LARSON
Treasurer




RICHARD ERWIN
Attorney General




DOYLE CONNER
Commissioner of Agriculture


W. RANDOLPH HODGES
Director




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 hy-
drology 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 Dis-
trict 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_ _~__ -____ 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 sta-
tions, 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





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








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 intercon-
nection 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






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.


Fig. 1. Greater Miami area showing major hydrologic features and the area
investigated.






REPORT OF INVESTIGATIONS No. 24


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. O. 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 water-
control system in the area, and the City of North Miami Beach
for providing the equipment for aquifer tests and records of pump-
age 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.






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 investi-
gated 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 configura-
tion 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 protec-
tion 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


rf'
V


4)
C,
OF At/

CO


EXPLANATION
COASTAL RIDGE
GLADE LINE
SCALE IN MILES
1 0 I z


Fig. 2. Greater Miami area showing the configuration of the natural drainage-
ways and the coastal ridge.





6 FLORIDA GEOLOGICAL SURVEY


Fig. 3. Photographs of salinity-control structure near mouth of Snake Creek
Canal.


!, .--I






REPORT OF INVESTIGATIONS No. 24


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 coast-
line 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 con-
trol 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 struc-
ture. 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.






FLORIDA GEOLOGICAL SURVEY


r


z-
m >


zA z










RED ROAD


ITE ROAD 7


Fig. 4. Geologic section along Snake Creek Canal. (Adaptd from U. S. Corps

of Engineers1954, pI: 94Y -





REPORT OF INVESTIGATIONS No. 24 9


So o. o ro o o o o(D


"X(iH 31XIG .. .
6 0119

9i119


















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SN3aV9 IV! 1


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o o- .-.o o o o .o
00.- a 0 0 -

73A 3 7 V3S.N V3k 01: S C33.,331-j -333 -''30n 7 1V -




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 con-
ventional methods and, from these measurements, the cross-
sectional 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 observa-
tion 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 in-
stalled 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 data-
collection 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


SNAKE CREEK CANAL
AT DOUGLAS ROAD






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 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 6:0 12.00 00 6:00




o SNAKE CREEK CANAL
ac 6 _- ---_y^-AT RED ROAD---- ---- ---- --- --- ---
6 R--- L ..AT-.A SNAKE R CREEK CANAL
u T \ MIAMI GARDENS DRIVE
-4C ............ "_ ____
I30, -~/ f~- --' I-* 7"7 --
pc SNAKE CREEK CANAL
C AT W DIXIE HWY




-4
SNAKE CREEK CANAL
rAT RED ROAD
o _____I ----- --- --
en "-----_ --
3------- ---------------- ------ _-___
LrL SNAKE CREEK CANAL
-- AT W. DIXIEHWY SNAKE CREEK CANAL
~I..-AT DOUGLAS ROAD
SNA KE CREEK HANAL L I
u AAT 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:






REPORT OF INVESTIGATIONS No. 24


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 struc-
ture. 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





FLORIDA GEOLOGICAL SURVEY


Fig. 8. Hydrographs of stage and discharge at selected canal stations during
test March 27-30, 1961.


structure. During long periods of heavy rainfall, ground-water
levels rise to 4 or 5 feet above msl 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
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 of
Snake Creek Canal to the western edge of Area B, during October







REPORT OF INVESTIGATIONS No. 24


MARCH 31
6:00 2 00


1961
600 12.00


APRIL I
12.00


U)
t.i
0
Z


(3
cr

















I
0













U







L

L

C


L,


Fig. 9.; Hydrographs of stage and discharge at selected canal stations during
flushing operationiMarch 31 to April 1, 1961.


\ SNAKE CREEK CANAL
AT W. DIXIE HWY


80C

/'-\ SNAKE CREEK CANAL
S AT RED ROAD /
40 ----- -- ---- "--

p,, SNAKE CREEK CANAL ~-
.a \.MlAMIGArRDENS DRIVE




-4C_00 ------_ -- t- ------ ----- --
00-






SSNAKE CREEK CANAL
> AT RED ROADs, "

LI

0


2. -- SNAKE CREEK .ANAL / K_____ ___
__ MATDOUGLAS ROAD /- -


Ld
D /
1I.5


Li .: AT MIAMI GARDENS DRIVE

-j

I SNAKE CREEK CANAL .
> AT W. DXIE HWY
Li


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~ ~ (II -U Rl C rm


16001--


.__i






FLORIDA GEOLOGICAL SURVEY


MARCH


1961


APRIL


Fig. 10 Hydrographs of selected wells and canal stations March 25 to April
3, 1961.


I I
,-WELL G85/


WELL 66/


WELL SELL 44


18r"^


I
/


~L





--


~W~LL
WEL


--t--
S1438
I


/e






REPORT OF INVESTIGATIONS NO. 24


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 Febru-
ary 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 con-
trol 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





FLORIDA GEOLOGICAL SURVEY


Fig. 11. Diagram 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).






REPORT OF INVESTIGATIONS NO. 24


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.




t 4 _. .

EXPLANATION I
S NDIRECTIONO F FLOWAND DISCHARGE.CFS
OUTFLOW I'CANAL REACH,CFS
S INFLOW IN CANAL REACH,CFS
D'* tE E INCHANNEL STORAGE
IN CANAL REAC.,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
















/


FLORIDA GEOLOGICAL SURVEY


______ I_______if____ I ____


i /____ ___I


//


I


TIME MEAN VELOCITY
8:18A.M. -0.15 ft/sec
---- 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
S CANAL BED _- 2:35 P.M. 1.67 ft/sec


-1 ~-UPSTREAM---<-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 ground-
water 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


I-


Lz

z


-
Q-t
Q





















S- ..j- .. .--i i i j ." .- ,





- r-'" .6 ... /.^^w..." %; ,, (/J.

.... o











Fig. 14. Snake Creek Canal area showing contours on the water table, March
27, 1961.
Gan "T 0 1.05
1*061I SL ,
..... *uPBS Is 5aT05IOLOS,



L! ------050--







Fig. 14. Snake Creek Canal area showing contours on the water table, March
27, 1961.






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 hydro-
graphs in figure 8. The maximum and minimum discharges and
water levels in the canal during this period are shown in figure
16.


Fig. 15. Snake Creek Canal showing average flow regime and water-level
profiles during March 27-30, 1961.






REPORT OF INVESTIGATIONS No. 24


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
Red Road to U. S. Highway 27 3,485,000

The rate of change in canal storage was computed by the
Ad
formula Qs= where Q, 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





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:
Q- 8,238,000 x 1.82 = 59 cfs
254,700
Red Road to U.S. Highway 27:
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 ground-
water 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 open-
ing of the control caused ground-water inflow to the canal in all














= .. ,, "9 s


14400
,__ --- ... ,;f^,^, ^_,


Fe. Fe
P266N -
F0 on the wt r452 04Mh ,9

S01050 4
'g-.-. Sn eCre--- C-,-- r h o u s /t le .Ma h,9, 1963



Fig. 17. Snake Creek area showing contours on the water table, March 29, 1961.






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 approxi-
mate 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 draw-
down 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


9:00 12:00 3:00 6:00
A M. M P.M. M.
PUMP ON WELL NO.3 --.

JUNE 9,1961
PUMPING WELL NO.11
800GPM

PUMP Off

K JUNE 13,1961
WELLS NO.4;,10ll.
---- PUMPING 2400 GPM,TOTAL-


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 draw-
down 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.


8*


DISTANCE FROM PUMPED WELL,IN FEET
100 200 3 400


10
8



/ JUNE 9,1961
PUMPING WELL NO.11
800 GPM

I I i I i I






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 de-
pendent 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 in-
dicated 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 x S
to
T = coefficient of transmissibility, in gallons per day per foot
S = coefficient of storage dimensionlesss)
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






REPORaT OF INVESTIGATIONS NO. 24


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 t-'IAL-RAN G.-6RUND-WAt E R
.ANGE RA TIDAL RANGE, CANAL TIME LAG IN HOURS
.o1 O .0 4.0 b5 0- --0.1- -. 0. 3.. 4 0 0.5 .- 1.0 1 1 2 3 4 6
28 1440 T=O.6OX ST
240 -- -
T 06Wo) \ s
D0151 2
|......o_ T=Z .3 X o S
200 -_____ ---- ^ -----S=0.15
SSX 42 T3.4x GPD per Ft.













Canal and selected wells/



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) ad probably not as reliable, but.
:k 120 -
\ '..
T.4 x" 1S .. (.. ..
go 0 __-_ ______ -- -- HOU-
for area where the aquifer is onl 045 ick (Schroeder,




















19S8), but it is supported by both the known occurrence of highly
400 T= 2.4XIO 10. S
If S.0,15 N G1053 7










GPpermeable materials in tat area and by sudie uderfow along
T-- S.9 X opt) pet -
._1__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, butch
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 trans-
missibility 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 interconnec-
tion between the canal and the aquifer in Area B indicate that this
reach of the Snake Creek Canal system would be a highly






FLORIDA GEOLOGICAL SURVEY


desirable area for the location of large future well fields. With-
drawals 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 ground-
water 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


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 con-
tinuing 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


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. 817-
834.
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 open-
file 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.




Hydrologic studies in the Snake Creek Canal area, Dade County, Florida ( FGS: Report of investigations 24, pt.3 )
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 Material Information
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 )
Physical Description: vi, 33 p. : illus., maps, diagrs. ; 23 cm.
Language: English
Creator: Leach, Stanley D
Sherwood, C. B ( joint author )
Geological Survey (U.S.)
Publisher: s.n.
Place of Publication: Tallahassee
Publication Date: 1963
 Subjects
Subjects / Keywords: Groundwater -- Florida -- Miami-Dade County   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by C. B. Sherwood and S. D. Leach.
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.
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Table of Contents
    Front Cover
        Page i
    Florida State Board of Conservation
        Page ii
    Transmittal letter
        Page iii
        Page iv
    Table of contents
        Page v
        Page vi
    Abstract and introduction
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
    Method of investigation
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 7
        Page 13
    Analysis of data
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 13
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    Summary
        Page 31
        Page 32
        Page 30
    Selected references
        Page 33
        Copyright
            Copyright
Full Text



STATE OF FLORIDA
STATE BOARD OF CONSERVATION
DIVISION OF GEOLOGY

FLORIDA GEOLOGICAL SURVEY
Robert 0. 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
Secretary of State




THOMAS D. BAILEY
Superintendent of Public Instruction




RAY E. GREEN
Comptroller


J. EDWIN LARSON
Treasurer




RICHARD ERWIN
Attorney General



DOYLE CONNER
Commissioner of Agriculture


W. RANDOLPH HODGES
Director




LETTER OF TRANSMITTAL


Lorida /eoloqical 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 hy-
drology 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 Dis-
trict 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 0. Vernon, Director
and State Geologist


iii


















































Completed manuscript received
January 24, 1963
Published for the Florida Geological Survey
By E. 0. 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 sta-
tions, 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





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








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 intercon-
nection 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






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.


Fig. 1. Greater Miami area showing major hydrologic features and the area
investigated.






REPORT OF INVESTIGATIONS No. 24


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 water-
control system in the area, and the City of North Miami Beach
for providing the equipment for aquifer tests and records of pump-
age 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.






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 investi-
gated 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 configura-
tion 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 protec-
tion 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


rf'
V


4)
OF Al
CO


EXPLANATION
COASTAL RIDGE
GLADE LINE
SCALE IN MILES
1 0 I z


Fig. 2. Greater Miami area showing the configuration of the natural drainage-
ways and the coastal ridge.





6 FLORIDA GEOLOGICAL SURVEY


Fig. 3. Photographs of salinity-control structure near mouth of Snake Creek
Canal.


!, .--I






REPORT OF INVESTIGATIONS No. 24


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 coast-
line 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 con-
trol 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 struc-
ture. 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 41/2 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.





FLORIDA GEOLOGICAL SURVEY


zz-

E ROm >










ffDROAD


ITE ROAD 7


Fig. 4. Geologic section along Snake Creek Canal. (Adapted from U. S. Corps
of Engineers1954, p1. 94Y -





REPORT OF INVESTIGATIONS No. 24 9


o o.oo a 0 oo ao


1 -b II C5 C91110 l6 ClM 5
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73A37 V3S.N V3k 011 C3I3.38 2 233 NI "30 i17V...
^ / "

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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 con-
ventional methods and, from these measurements, the cross-
sectional 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 observa-
tion 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 in-
stalled 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 data-
collection 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


SNAKE CREEK CANAL
z ATDOUGLAS ROAD



SIw

0

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 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:o0 12 :00 61200 00 00-----



o SNAKE CREEK CANAL
ac 6 _- ---_y^-AT RED ROAD---- ---- ---- --- --- ---
6- R- SNAKE C R REEK CANAL
u T \ MIAMI GARDENS DRIVE
4C ....... .......
"-_ -~"-' -7 ----
pc SNAKE CREEK CANAL
C AT W DIXIE HWY.



-4
SNAKE CREEK CANAL
AT RED ROAD ____________
o-" _____ --- --'-=r ---- ~ ---I---_---_---
43------ ------ ---------------- ------ _______.
S SNAKE CREEK CANAL _____
je-- AT W. DIXIEHWY- SNAKE CREEK CANAL
~i...-eAT DOUGLAS ROAD
SNAKECEKANKE CREEK -A LI
'u AAT 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 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:






REPORT OF INVESTIGATIONS No. 24


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 coast-
line 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 con-
trol 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 struc-
ture. 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 41/2 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.






REPORT OF INVESTIGATIONS No. 24


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 struc-
ture. 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





FLORIDA GEOLOGICAL SURVEY


Fig. 8. Hydrographs of stage and discharge at selected canal stations during
test March 27-30, 1961.


structure. During long periods of heavy rainfall, ground-water
levels rise to 4 or 5 feet above msl 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
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 of
Snake Creek Canal to the western edge of Area B, during October







REPORT OF INVESTIGATIONS No. 24


MARCH 31
6:00 2 00


1961
600 12.00


APRIL I
12.00


U)
t.i
0
Z
2

C,
(.

0
0U





U





U
U'








L

L
C
L


Lt


I
I

L,


I


Fig. 9.; Hydrogrdphs of stage and discharge at.selected canal stations during
flushing operatiobnMarch 31 to April 1, 1961.


\ SNAKE CREEK CANAL
AT W. DIXIE HWY


80C

/'\ SNAKE CREEK CANAL
S V- AT RED ROAD /
40 ----- -- ----- "--

.! ". ,, SNAKE CREEK CANAL -.





-400 -- ----- -------- |t --- -- -- -
100




SNAKE CREEK CANAL -
> AT RED ROADs, "






d2. \SNAKE CREEK CANAL/ _______ _
SATDOUGLAS ROAD /



t1.5 \ /

I .SNAKE CREEK CANAL
Li .: AT MIAMI GARDENS DRIVE



A SNAKE CREEK CANAL I
> AT W.DIXIE HWY
r


~ ~ (II -U Rl C rm


16001--


.__






FLORIDA GEOLOGICAL SURVEY


MARCH


1961


APRIL


Fig. 10 Hydrographs of selected wells and canal stations March 25 to April
3, 1961.


I I
,-WELL G85/


WELL 66/


WELL,, S1442
WE L 144 EL /


18r"^


I


~L





--


\C~WELL


S1438
I


F





REPORT OF INVESTIGATIONS NO. 24


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 Febru-
ary 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 con-
trol 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





FLORIDA GEOLOGICAL SURVEY


Fig. 11. Diagram 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).






REPORT OF INVESTIGATIONS No. 24


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 struc-
ture. 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






REPORT OF INVESTIGATIONS NO. 24


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
N DIRECTION OF FLOWAND DISCHARGE.CFS
OUTFLOW I"CANAL REACH,CFS
S INFLOW IN 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

















/


FLORIDA GEOLOGICAL SURVEY


_________ I __________ if ______ I II _______


i /____ ___I


/


i


TIME MEAN VELOCITY
8:18 A.M. -0.15 ft/sec
2---- 9:15A.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


-1 ~--UPSTREAM---<-DOWNSTREAM--1I 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 ground-
water 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


I-


tJ
Lz
zt


a-
a_
Q-t
U1
Q




















J-..%. j .--i i --W.-... 1 -0 U,


I L.. 0...r.. .".".i ...- l 1 \'/ .s'
r .f ... / ^..." ,,, (
a.I. y
'201*6615













Fig. 14. Snake Creek Canal area showing contours on the water table, March
27, 1961.
Fig-- 14EL SnkFreIaalae hwn cnor ntELwtrD al, ac
....... ~ ~ ~ 27 1961.O 05 ~r-o





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 hydro-
graphs in figure 8. The maximum and minimum discharges and
water levels in the canal during this period are shown in figure
16.


Fig. 15. Snake Creek Canal showing average flow regime and water-level
profiles during March 27-30, 1961.






REPORT OF INVESTIGATIONS No. 24


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
Red Road to U. S. Highway 27 3,485,000

The rate of change in canal storage was computed by the
Ad
formula Qs= where Q, 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





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:
9,72,000 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:
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
efs, 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 ground-
water 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, = QQ- 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 open-
ing of the control caused ground-water inflow to the canal in all









-., -.. ..-y ,-,."'--- .o ...2W2'i8Thd .,
= 4.h. .- s |

Sri---, -...' c, Ds,






Fig. 17. Snake Creek area showing contours on the water table, March 29, 1961.






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 approxi-
mate 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 draw-
down 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


9:00 12:00 3:00 6:00
A M. M P.M. PM.
PUMP ON WELL NO.3 --,.

PUMPING WELL NO.11
800 GPM

PUMP OFF

JUNE 13,1961
WELLS NO.4,-10,-Or.
PUMPING 2400 GPM,TOTAL-


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 draw-
down 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.


8*


DISTANCE FROM PUMPED WELL, IN FEET
100 200 3 400


I8



/ JUNE 9,1961
PUMPING WELL NO.11
800 GPM

I I i I i I






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 de-
pendent 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 in-
dicated 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 dimensionlesss)
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






REPORaT OF INVESTIGATIONS NO. 24


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 t-'IAL-RAN G.-6RUND-WAt E R
.A N.. RA TIDAL RANGE, CANAL TIME LAG IN HOURS
.o1 O .0 4.0 b5 0- --0.1- -. 0. 3.. 4 0 0.5 .- 1.0 1 1 2 3 4 6
28 1440 T=O.6OX ST
240 -- -
T S \ Wo104 5s
D0151 2
|......o_ T=Z .3 X o S
200 -_____ ---- ^ -----S=0.15
SS=42 3.4X O6 GPD per Ft.



vlI i hig t thIu
"at ( Io 2. -1 o a p o bl n reib'Iu
:k 120 -
\ '..
T.4 x" 1S .. (.. ..
go 0 __-_ ______ -- -- HOU-
S 1045 ^ -
400 T= 2.4XIO 10. S
If S.0,15 N G1053 7
T-- S.9 X opt) pet -
._1__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 trans-
missibility 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 interconnec-
tion between the canal and the aquifer in Area B indicate that this
reach of the Snake Creek Canal system would be a highly





FLORIDA GEOLOGICAL SURVEY


desirable area for the location of large future well fields. With-
drawals 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 ground-
water 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


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 con-
tinuing 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.








FLORIDA GEOLOGICAL SURVEY


desirable area for the location of large future well fields. With-
drawals 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 ground-
water 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


SELECTED REFERENCES

Cooper, H. H., Jr.
Type curves for nonsteady radial flow in an infinite leaky aquifer:
U. S. Geol. Survey Water-Supply Paperi (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. 817-
834.
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 open-
file 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.










FLRD GEOLIOWC( ICA SURflViEWY~


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