Freshwater Flow from Estuarine Creeks

into Northeastern Florida Bay

U.S. Geological Survey

Water-Resources Investigations Report 01-4164

Prepared as part of the

U.S. GEOLOGICAL SURVEY PLACE-BASED STUDIES PROGRAM
U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 01-4164

Freshwater Flow from Estuarine Creeks into

Northeastern Florida Bay

Tallahassee, Florida

2001

By Clinton Hittle, Eduardo Patino, and Mark Zucker

Prepared as part of the

U.S. Geological Survey Place-Based Studies Program
Copies of this report can be

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U.S. Geological Survey

Branch of Information Services

Box 25286

Denver, CO 80225-0286

888-ASK-USGS

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write to:

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Suite 3015

227 N. Bronough Street

Tallahassee, FL 32301

Additional information about water resources in Florida is available on the World

Wide Web at http://fl.water.usgs.gov

U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, Director
Contents III

CONTENTS

Abstract.................................................................................................................................................................................. 1

Introduction ........................................................................................................................................................................... 2

Purpose and Scope....................................................................................................................................................... 2

Description of Study Area ........................................................................................................................................... 2

Acknowledgments ...................................................................................................................................................... 8

Methods of Investigation ...................................................................................................................................................... 8

Field Data Collection .................................................................................................................................................. 8

Development of Cross-Sectional Area ....................................................................................................................... 12

Computing Freshwater Flow from Estuarine Creeks into Florida Bay ................................................................................ 12

Velocity Estimation Model for Instrumented Sites ..................................................................................................... 12

Case 1 ................................................................................................................................................................ 13

Case 2 ................................................................................................................................................................ 13

Case 3 ................................................................................................................................................................ 15

Estimated Flow at Noninstrumented Sites .................................................................................................................. 17

Discharge Analysis and General Streamflow Characteristics .................................................................................... 19

Seasonal Flow Patterns ..................................................................................................................................... 19

Spatial Distribution of Freshwater Flow and Salinity ...................................................................................... 20

Base-Gage Selection and Discharge Relation .................................................................................................. 23

Summary and Conclusions ................................................................................................................................................... 24

References Cited ................................................................................................................................................................... 25

Appendix: Data Set Used to Develop Velocity Relations for the Monitoring Stations......................................................... 27

FIGURES

1. Map showing location of Florida Bay monitoring stations ..................................................................................... 3

2-7. Photographs showing:

2. West Highway Creek monitoring station in Florida Bay ............................................................................... 4

3. Trout Creek monitoring station in Florida Bay .............................................................................................. 5

4. Mud Creek monitoring station in Florida Bay ............................................................................................... 6

5. Taylor River monitoring station in Florida Bay ............................................................................................. 7

6. McCormick Creek monitoring station in Florida Bay ................................................................................... 7

7. Boat-mounted Acoustic Doppler Current Profiler for measuring discharge at the Trout Creek

monitoring station ........................................................................................................................................... 9

8-9. Diagrams showing:

8. Velocity components used in the traveltime equation..................................................................................... 9

9. Acoustic instrument configurations for Florida Bay monitoring stations ...................................................... 10

10-11. Photographs showing:

10. Acoustic transducers at West Highway Creek monitoring station ................................................................. 11

11. Two salinity/temperature probes used at a Florida Bay monitoring station ................................................... 11

12. Diagram of cross-sectional area for the McCormick Creek monitoring station ..................................................... 12

13-14. Graphs showing:

13. Velocity relation for the McCormick Creek, Mud Creek, and Trout Creek monitoring stations ................... 14

14. Mean measured to estimated velocity relation for the West Highway Creek monitoring station .................. 15

15. Diagram showing complex flow characteristics with vertical circulation patterns at the Taylor River

monitoring station ................................................................................................................................................... 15

16-19. Graphs showing:

16. Mean measured to estimated velocity relation for the Taylor River monitoring station ............................... 16
IV Contents

17. Relation of discharge between the West Highway Creek monitoring station (instrumented site)

and the Stillwater Creek, Oregon Creek, and East Highway Creek monitoring stations

(noninstrumented sites) .................................................................................................................................. 18

18. Relation of discharge between the East Creek monitoring station (noninstrumented site) and the

Taylor River and Mud Creek monitoring stations (instrumented sites) ......................................................... 19

19. Brackish water (dry season) to freshwater (wet season) transition at the Taylor River monitoring

station ............................................................................................................................................................ 20

20. Bar graphs showing wet- and dry-season freshwater discharges for the McCormick Creek, Taylor River,

Mud Creek, Trout Creek, and West Highway Creek monitoring stations, May 1996 to April 1999 ..................... 21

21. Pie chart showing percentage distribution of total freshwater discharge for the Florida Bay monitoring

stations, May 1996 to September 1999 .................................................................................................................. 22

22. Hydrograph showing mean monthly flows and salinity values for the McCormick Creek, Taylor River,

Mud Creek, Trout Creek, and West Highway Creek monitoring stations, October 1995 through

September 1999 ...................................................................................................................................................... 22

23. Plots showing relation of discharge between Trout Creek and other selected monitoring stations in

northeastern Florida Bay ......................................................................................................................................... 23

TABLES

1. Description of Florida Bay monitoring stations...................................................................................................... 3

2. Different forms of the velocity estimation model tested for the Taylor River monitoring station.......................... 17

3. Results of correlation analyses for determining discharge at the East Highway Creek, Oregon Creek,

Stillwater Creek, and East Creek monitoring stations............................................................................................. 17
Abstract 1

Freshwater Flow from Estuarine Creeks into

Northeastern Florida Bay

By Clinton Hittle, Eduardo Patino, and Mark Zucker

Abstract

Water-level, water-velocity, salinity, and

temperature data were collected from selected

estuarine creeks to compute freshwater flow into

northeastern Florida Bay. Calibrated equations for

determining mean velocity from acoustic velocity

were obtained by developing velocity relations

based on direct acoustic measurements, acoustic

line velocity, and water level. Three formulas were

necessary to describe flow patternsfor all monitoring sites, with R2 (coefficient of determination)

values ranging from 0.957 to 0.995. Crosssectional area calculations were limited to the

main channel of the creeks and did not include

potential areas of overbank flow. Techniques also

were used to estimate discharge at noninstrumented sites by establishing discharge relations to

nearby instrumented sites.

Results of the relation between flows at

instrumented and noninstrumented sites varied

with R2 values ranging from 0.865 to 0.99. West

Highway Creek was used to estimate noninstrumented sites in Long Sound, and Mud Creek was

used to estimate East Creek in Little Madeira Bay.

Mean monthly flows were used to describe flow

patterns and to calculate net flow along the northeastern coastline. Data used in the study were collected from October 1995 through September

1999, which includes the El NiÒo event of 1998.

During this period, about 80 percent of the freshwater flowing into the bay occurred during the wet

season (May-October). The mean freshwater

discharge for all five instrumented sites during the

wetseason from 1996 to 1999 is 106 cubic feet per

second. The El NiÒo event caused a substantial

increase (654 percent) in mean flows during the

dry season (November-April) at the instrumented

sites, ranging from 8.5 cubic feet per second in

1996-97 to 55.6 cubic feet per second in 1997-98.

Three main flow signatures were identified

when comparing flows at all monitoring stations.

The most significant was the magnitude of discharges at Trout Creek, which carries about

50 percent of the total measured freshwater entering northeastern Florida Bay. The mean monthly

wet-season (May-October) flow at Trout Creek is

about 340 cubic feet per second, compared to

55 cubic feet per second at West Highway Creek,

52 cubic feet per second at Taylor River, 49 cubic

feet per second at Mud Creek, and 33 cubic feet

per second at McCormick Creek. The other two

flow signatures are the decline of freshwater discharge at McCormick Creek at the start of the

El NiÒo event, and the absence of net-negative

flows at West Highway Creek. The observed flow

distribution within the study area,suggeststhat the

overall flow direction of freshwater in the Everglades wetlands in the lower part of Taylor Slough

may have a strong eastward flow component as

water approaches the coastline. Data analysis also

indicates that Trout Creek could potentially be

used as a long-term monitoring station to estimate

total freshwater flow into northeastern Florida

Bay, provided that the remaining questions regarding flow patterns at McCormick Creek and the

creeks in Long Sound are answered and that no

major changes in flow characteristics occur in the

future.
2 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

INTRODUCTION

Historical changes in water-management practices to accommodate a large and rapidly growing

urban population along the Atlantic coast as well as

intensive agricultural activities have resulted in a

highly managed hydrologic system in southern Florida

with canals, levees, and gated and pumping-control

stations. These structures have altered the hydrology of

the Everglades ecosystem, including Florida Bay.

During the last decade, Florida Bay has experienced

seagrass die-off and algal blooms. Both are possible

signals of ecological deterioration that has been attributed to an increase in salinity and nutrient content of

bay waters (Davis and Ogden, 1997).

With plans to restore water levels in the Everglades wetlands to more ì naturalî conditions, changes

also are expected in the amount and timing of freshwater exiting the mainland through the major creeks into

northeastern Florida Bay. Flow through the estuarine

creeks into northeastern Florida Bay is naturally controlled by the water-level conditions of the Everglades

wetlands; regional wind patterns; and to a lesser extent,

tides.

Restoration of the Florida Bay ecosystem

requires an understanding of the linkage between the

amount of freshwater flowing into the bay and the

salinity and quality of the bay environment. Historically, there has been no accurate quantification of the

amount of freshwater being discharged into Florida

Bay from the mainland due to the difficulties of accurately gaging flows in shallow, bidirectional, and vertically stratified streams. In October 1995, the U.S.

Geological Survey (USGS) began a study to gage several major creeks that discharge freshwater from the

mainland into northeastern Florida Bay. The focus of

the study was to provide flow, salinity, and water-level

data for model development and calibration and also to

provide data for other physical, biological and chemical studies being conducted in the area. The study was

done as part of the USGS Place-Based Studies Program, which is an effort by the USGS along with various other Federal, State, and local agencies to provide

earth science information needed to resolve land-use

and water issues in southern Florida. Results from the

study will provide scientists with essential information

along the Everglades wetland/Florida Bay transition

zone where data were not previously available.

Purpose and Scope

The purpose of this report is to describe the magnitude and distribution of flows at nine estuarine creeks

within the mangrove zone along the northeastern coast

of Florida Bay. Procedures used at five instrumented

sites to calculate the cross-sectional area are presented

in detail, and analyses made to establish the relations

between acoustic line velocity and mean water velocity

for the computation of discharge are presented. Estimation techniques also are presented for determining

flows at four noninstrumented sites and for the selection of a base gage to indicate possible effects that

changes in water-management practices may have on

the freshwater flow into northeastern Florida Bay. General flow patterns are described by presenting seasonal

variations in discharge and salinity during wet- and

dry-season months and the spatial distribution of discharge from east to west along the coastline.

Description of Study Area

Florida Bay, home to several endangered species, such as the American crocodile and Florida manatee, is a valuable breeding ground for marine life and

an important recreational and sport fishing area. The

bay encompasses an area of about 850 mi2 (square

miles) with an average depth of less than 4 ft (feet). It

is bordered by Everglades National Park to the north,

the Florida Keys to the east and south, and is open to

the Gulf of Mexico to the west (fig. 1).

The study area is located within the mangrove

zone along the northeastern coastline of Florida Bay.

This area is characterized by a natural ridge or embankment, which parallels the coastline from U.S. Highway

1 (US-1) to Flamingo (fig. 1). Relatively few creeks cut

through the embankment, facilitating water exchange

between Florida Bay and the Everglades wetlands.

Localized rainfall, Taylor Slough, and the C-111 Canal

are the main sources of freshwater into northeastern

Florida Bay. Nine creeks along the southern Florida

coastline were selected to study the exchange of water

between the Everglades and Florida Bay. These creeks,

from east to west are: East Highway Creek, West Highway Creek, Oregon Creek, Stillwater Creek, Trout

Creek, Mud Creek, East Creek, Taylor River, and

McCormick Creek (fig. 1 and table 1).
Introduction 3

Table 1.  Description of Florida Bay monitoring stations

[Horizontal coordinate information referenced to North American Vertical

Datum of 1988]

Station name Latitude Longitude Type of site

East Highway Creek 251440 802628 Noninstrumented

West Highway Creek 251433 802650 Instrumented

Oregon Creek 251422 802719 Noninstrumented

Stillwater Creek 251341 802912 Noninstrumented

Trout Creek 251253 803201 Instrumented

Mud Creek 251209 803501 Instrumented

East Creek 251153 803708 Noninstrumented

Taylor River 251127 803821 Instrumented

McCormick Creek 251003 804355 Instrumented

CAPE SABLE

C-111

FLORIDA KEYS

Taylor Slough

0

0

5 10 MILES

5 10 KILOMETERS

Location

of

Study Area

Flamingo GULF OF MEXICO

Terrapin Bay

Monroe Lake

Manatee Bay

McCormick Creek

Taylor River

East Creek

Mud Creek

Trout Creek

Stillwater Creek

Oregon Creek

West Highway Creek

East Highway Creek

Little Madeira Bay

Joe Bay

Alligator Bay

Long Sound

ATLANTIC OCEAN

Florida Bay





 	 


Monitoring station

EXPLANATION

EVERGLADES

NATIONAL PARK

1

Figure 1.  Location of Florida Bay monitoring stations. The instrumented and noninstrumented sites are identified

in table 1.
4 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

East and West Highway Creeks are located along

the northeastern edge of Long Sound and are hydraulically connected to C-111 Canal and Manatee Bay. East

Highway Creek is about 0.2 mi (mile) west of US-1

(fig. 1) and is about 35 ft wide and 4.5 ft deep. West

Highway Creek is about 0.4 mi west of US-1 (fig. 1)

and is about 65 ft wide and 5 ft deep. A photograph of

the West Highway Creek monitoring station is shown

in figure 2.   

Oregon and Stillwater Creeks are located along

the northern shore of Long Sound. Both creeks are

hydraulically connected to C-111 Canal, with Stillwater Creek also connected to Joe Bay. Oregon Creek is

about 0.6 mi west of US-1 (fig. 1) and is about 18 ft

wide and 4 ft deep. Stillwater Creek is about 1.5 mi

west of US-1 (fig. 1) and is about 30 ft wide and 4 ft

deep.

Trout Creek is located at the mouth of Joe Bay

and is hydraulically connected to Taylor Slough,

C-111 Canal, and Long Sound. The creek is about 7 mi

west of US-1 (fig. 1) and is about 500 ft long, 110 ft

wide, and 5 ft deep. Photographs of the Trout Creek

monitoring station are shown in figure 3.

Mud Creek islocated near the mouth of Alligator

Bay and is hydraulically connected to Taylor Slough

and Joe Bay. The creek is about 10 mi west of US-1

(fig. 1) and is about 40 ft wide and 5 ft deep.  

Photographs of the Mud Creek monitoring station are

shown in figure 4.

East Creek is located in Little Madeira Bay and

is hydraulically connected to Taylor Slough and Mud

Creek through upstream ponds. The creek is about

14 mi west of US-1 (fig. 1) and is about 25 ft wide and

4 ft deep.  

Taylor River islocated in Little Madeira Bay and

is hydraulically connected to Taylor Slough. The creek

is about 15 mi west of US-1 (fig. 1) and is about 22 ft

wide and 5 ft deep near its mouth. A photograph of the

Taylor River monitoring station is shown in figure 5.

McCormick Creek islocated about 20 mi west of

US-1 and is hydraulically connected to Monroe Lake

and Terrapin Bay (fig. 1). The creek also has a

hydraulic connection to Seven Palm and Middle Lakes

(near Monroe Lake but not shown in fig. 1) and to

Taylor Slough. A photograph of the McCormick Creek

monitoring station is shown in figure 6.

Figure 2.  West Highway Creek monitoring station in Florida Bay.
Introduction 5

LOOKING NORTH INTO JOE BAY

LOOKING SOUTH INTO FLORIDA BAY

TROUT CREEK MONITORING STATION

Figure 3.  Trout Creek monitoring station in Florida Bay.
6 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

LOOKING INTO ALLIGATOR BAY

MUD CREEK MONITORING STATION

Figure 4.  Mud Creek monitoring station in Florida Bay.
Introduction 7

                               

Figure 5.  Taylor River monitoring station in Florida Bay.

Figure 6.  McCormick Creek monitoring station in Florida Bay.
8 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Acknowledgments

The authors are grateful to Robert Fennema,

Freddie James, and Robert Brock from the research

center of Everglades National Park; David King and

David Fowler at the Key Largo Ranger Station for their

input during the design stages of the study; and Lucy

Given for the use of park facilities and research boats.

The authors also thank the USGS National Mapping

Division team for supplying the vertical levels needed

to relate water levels at the monitoring stations. Finally,

thanks are extended to the Florida Bay researchers at

the South Florida Water Management District, Florida

International University, and Louisiana State University for thoughtful discussions about Florida Bay and

the Everglades ecosystem.

METHODS OF INVESTIGATION

This section presents the methods that were used

in the study to describe the magnitude and distribution

of flow at nine estuarine creeks along the northeastern

coastline of Florida Bay. The first part is a discussion

of the data collected in the field at both the instrumented and noninstrumented sites (table 1). The

second part describes the procedures used for the

calculation of a cross-sectional area at the monitoring

stations.

Field Data Collection

At all instrumented sites (West Highway Creek,

Trout Creek, Mud Creek, Taylor River, and McCormick Creek), data collection included continuous

15-minute interval measurements of water level, water

velocity, salinity, and temperature and periodic measurements of discharge for acoustic line velocity calibrations. All raw data at the instrumented sites were

recorded by an electronic data logger and transmitted

every 4 hours by way of the Geostationary Operational

Environmental Satellite (GOES) into the database of

the USGS Miami Subdistrict office. Data collection at

the noninstrumented sites (East Highway Creek,

Oregon Creek, Stillwater Creek, and East Creek) was

limited to periodic discharge and salinity measurements.

Acoustic Doppler Current Profilers (ADCPís)

mounted on a boat were used to measure discharge at

the Florida Bay monitoring stations. The ADCP uses

the Doppler shift in returned acoustic signals reflected

by particles suspended in the water to determine the

velocity of moving water (RD Instruments, 1989). This

instrument also has the capability to measure water

depth and speed and direction of the boat based on

acoustic reflectionsfrom the streambed. Discharge and

flow direction are both calculated from information

provided by the ADCP and computer software. The

mean water velocity for the stream or creek section is

calculated by dividing the total discharge (measured

with the ADCP) by the cross-sectional area corresponding to the water level at the time of measurement.

The cross-sectional area is computed by using the sitespecific stage area ratings (described later). A photograph of a boat-mounted ADCP and its operation is

shown in figure 7.

Water-level data were recorded to determine

water depth and to calculate the stage-dependent crosssectional area. Water-level data were collected with an

incremental shaft encoder equipped with a pulley,

stainless-steel tape, weight, and float inside an 8 in.

(inch) polyvinyl chloride pipe stilling well. All waterlevel data were originally referenced to an arbitrary

elevation and then corrected to the North American

Vertical Datum of 1988 after global positioning system

(GPS) surveys in 1997 by the USGS.

Acoustic velocity meter (AVM) systems, which

have proven to be accurate and reliable instruments

capable of measuring near-zero velocities in open

channels (Laenen and Curtis, 1989), were used to measure continuous water velocity. These AVM systems

measure the velocity of flowing water by means of an

acoustic signal (transmitted by transducers) that travels

faster when carried with the flow than against it. Water

velocity measured using this technique is referred to as

acoustic line velocity. Traveltimes are measured from

transducers located at point a to b and at point b to a as

shown in figure 8. The path traveled between transducers

is called the ì acoustic path.î To obtain water velocity,

the difference in traveltimes between transducers is

calculated in conjunction with the acoustic path length

and the angle of the path length with respect to flow.
Methods of Investigation 9

Figure 7.  Boat-mounted Acoustic Doppler Current Profiler for measuring discharge at the Trout Creek

monitoring station. Doppler is shown in inset.

a tba

tab

b

L

Vi



t

ba

tab

a,b

L

Vi



Acoustic transducers

Acoustic path length

Angle of acoustic path with

respect to flow

Traveltime

from a to b

of the acoustic

signal

Traveltime of the acoustic

signal from b to a

Acoustic line velocity

EXPLANATION

Stream bank

Stream bank

Figure 8.  Velocity components used in the traveltime equation. Modified from

Laenen and Curtis (1989).
10 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

The general equation to calculate water velocity is

defined by Laenen and Smith (1983) as follows:

, (1)

where

Vl is the acoustic line velocity at the depth of the

acoustic path,

L is the acoustic path length,

θ is the angle of the acoustic path with respect to

the flow,

tba is the traveltime of the acoustic signal from

point b to a, and

tab is the traveltime of the acoustic signal from

point a to b.

The acoustic line velocity (Vl

) measured by the

AVM systems represents an averaged value across the

stream from point a to b at a fixed depth and is considered to be an ì indexî of the mean water velocity. An

index velocity is a measured velocity at the instrumented sites that can be used to compute the mean

velocity. At West Highway Creek, Mud Creek, and

McCormick Creek, acoustic line velocity wasrecorded

at two depths (top and bottom); at Trout Creek and

Taylor River, the acoustic line velocity was recorded at

three depths (top, middle, and bottom). It was determined that all of the monitoring stations, except for

Taylor River, required only one index velocity at a

fixed depth to determine mean water velocity

(appendix). Acoustic instrument setup configurations

for the Florida Bay monitoring stations are shown in

figure 9. A photograph of acoustic transducers being

serviced at the West Highway Creek monitoring station

is shown in figure 10.

Originally,salinity was measured at three depths

(top, middle, and bottom of depth profile) for the Florida Bay monitoring stations to examine potential

effects on the acoustic signals caused by salinity stratifications and to help qualify the presence of freshwater

flow. The middle salinity probe was removed from

McCormick Creek, Mud Creek, and West Highway

Creek due to a low occurrence of salinity stratification

at these sites. Temperature was measured to monitor

possible vertical gradients that also could affect

acoustic signals. A photograph of the salinity and

temperature probes used at a Florida Bay monitoring

station is shown in figure 11.

Vl

L

2 cosθ ---------------     1

tba

------ 1

tab

ñ ------     =

SIDE VIEW

TOP VIEWS

Taylor River All other sites

Satellite

transmitter

Salinity and

temperature

Water surface probes

Streambed

Flow

direction

Flow

direction

Acoustic velocity

meter transducers

Acoustic

velocity

meter

transducers

Acoustic velocity

meter transducers

Platform

Mangrove

Mangrove

Mangrove

Mangrove

Platform

Florida

Bay

Figure 9.  Acoustic instrument configurations for Florida Bay monitoring stations.
Methods of Investigation 11

Acoustic

velocity meter

transducers

Figure 10.  Acoustic transducers

(above water level for servicing) at

West Highway Creek monitoring

station.

Figure 11.  Two salinity/temperature

probes used at a Florida Bay monitoring

station.
12 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Development of Cross-Sectional Area

The ADCP was used to make depth soundings at

specific distances across the width of each creek along

with simultaneous water-level readings at the time of

measurement. The data were used to develop a relation

between water level and total cross-sectional area for

the individual sites. The Channel Geometry Analysis

Program (CGAP) was used to compute the stage-area

rating (Regan and Schaffranek, 1985).

Overbank flow may occur at extreme high-water

conditions, extending the actual flow cross section a

distance beyond the main channel of the stream. Based

on field observations, overbank flow does not commonly occur; flow usually is confined to the creeks cutting through the embankment along the coastline of

northeastern Florida Bay. In order to quantitatively

assess the effect of overbank flow, accurate elevations

on the embankment would be needed; however, accurate elevations currently do not exist. As a result and to

maintain consistency and accuracy for calculated discharge values, a fictitious ì wallî was placed 5 ft from

the bank edges as shown in figure 12. Thus, calculated

discharge implies the use of areas within these ì walls,î

and represents flow through the main channel. Overland sheetflow is considered a separate body of water

with different velocity characteristics, and therefore,

discharge estimations were not attempted for these

areas. Accurate elevation data along the embankment

would be needed to compare against water levels to

verify that sheetflow is an insignificant contributor of

freshwater to Florida Bay. Existing water levels, salinity data, and visual indicators at the Florida Bay monitoring stations indicate that the majority of freshwater

flow is through the creeks and not over the embankment.

10

5

0

-5

-10 ELEVATION, IN FEET

-20 -10 0 10 20 30 40 50

DISTANCE, IN FEET

Estimated for cross-sectional

area computations

Figure 12.  Cross-sectional area for the McCormick Creek

monitoring station.

COMPUTING FRESHWATER FLOW FROM

ESTUARINE CREEKS INTO FLORIDA BAY

As previously described, field data were

collected and a stage-area rating was developed at nine

monitoring stations to calculate freshwater flow from

estuarine creeksinto Florida Bay. Three case scenarios,

based on a velocity estimation model, are presented to

describe flows under varying conditions at the instrumented sites in Florida Bay (West Highway Creek,

Trout Creek, Mud Creek, Taylor River, and McCormick Creek). Other methods were used to estimate flow

at the noninstrumented sites in Florida Bay (East Highway Creek, Oregon Creek, Stillwater Creek, and East

Creek), and the results are presented here. The subsequent sections present an analysis of seasonal flow

patterns, the spatial distribution of freshwater flow and

salinity distribution, discharge relations, and base-gage

selection.

Velocity Estimation Model for

Instrumented Sites

In order to develop a time-series record of mean

water velocity for any stream using acoustic line velocity data, it is necessary to establish a relation between

the recorded acoustic line velocities and directly measured mean water velocity. The relation existing

between index and mean velocities can be affected by a

number of physical factors that may need to be considered in the estimation model. As flow conditions

change, it is impractical and usually unnecessary to

account for all the physical factors affecting the velocity relation. At all monitoring stations in northeastern

Florida Bay, the acoustic line velocity and water-level

data were sufficient to describe the velocity relations, and no other parameters were necessary. A

series of velocity measurements (back calculated

from ADCP discharge measurements) made over

the range of expected conditions for all significant

variables was needed to define the effects of these

variables on the velocity relation. The technique

used to describe the velocity relation is a least

squares regression model in the single or multiple

variable form depending on the number of identified significant variables. The model uses the following equation form modified from Patino and

Ockerman (1997):
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 13

, (2)

where

V is the mean water velocity,

n is the total number of acoustic paths,

Vi is the acoustic line velocity; i represents the

top (1), middle (2), or bottom path (3),

Xi is a regression coefficient,

Yi is a regression coefficient associated with

stage,

H is stage, and

C is the intercept or constant.

This model allows for the fact that expected

changesin the mean water velocity, V, for a unit change

in the acoustic line velocity, V1-3, also can be a factor

of stage. Three different cases (or forms) of this model

were used to describe flow conditions at the study sites.

These cases are described in detail in the subsequent

sections.

Case 1

This form of the model is used to describe the

simplest flow condition for which the acoustic line

velocity is the only significant variable necessary to

describe the mean velocity of the stream. For this case,

equation 2 takes the following form:

. (3)

To solve equation 3, a linear regression analysis

is performed using Vi (acoustic line velocity) as the

independent variable, and V (mean measured velocity

from ADCP discharge measurements) asthe dependent

variable. At the Florida Bay monitoring stations where

equation 3 is used, the relation established between

acoustic and mean velocities requires the use of only

one of the measured acoustic line velocities; stage is

not a factor; that is, the velocity profile does not change

substantially with changing stage (eq. 3 has a constant

slope). Equation 3 is used to describe flow conditions

at McCormick Creek, Mud Creek, and Trout Creek.

The data used for the analysis, rated velocity and discharge, and residual values of discharge are presented

in the appendix. Residual values are the difference

between measured and rated discharge.

Flow conditions at McCormick Creek are such

that a relation was obtained between acoustic line and

mean velocities for all measured flow conditions

(fig. 13). Even though bidirectional flow can be present

at this site from time to time, it does not occur

frequently nor for extended periods of time.

Bidirectional flow occurs mainly during times of shifting wind patterns. Computation of mean velocity and

discharge was performed for the majority of record

using the acoustic line velocity from the top AVM path

(velocity no. 1). The equation for AVM velocity no. 1

is V = 0.552 Vi − 0.016, with an R2 (coefficient of determination) value of 0.977 and a standard error for the

velocity estimate of 0.082 ft/s (foot per second).

Flow conditions at Mud Creek also resulted in a

relation between acoustic line velocities and mean

velocities(fig. 13). As with McCormick Creek, computation of mean velocity and discharge for Mud Creek

was performed using the acoustic line velocity from the

top AVM path (velocity no. 1). The equation for AVM

velocity no. 1 is V = 0.448 Vi − 0.024, with an R2 value

of 0.993 and a standard error for the velocity estimate

of 0.031 ft/s.

Flow conditions at Trout Creek show a tight relation between acoustic line velocity and mean water

velocity (fig. 13). Computation of mean velocity and

discharge was performed using the acoustic line velocity

from the middle AVM path (velocity no. 2). The equation for AVM velocity no. 2 is V = 0.705 V2 − 0.031,

with an R2 value of 0.995 and a standard error for the

velocity estimate of 0.056 ft/s. The velocity relation for

Trout Creek is shown in figure 13 (using velocity

no. 2).

Case 2

Case 2 is used to describe velocities at sites that

present different flow conditions for positive and negative flows. Because differentspatial velocity variations

were observed for positive and negative flows at West

Highway Creek, it was necessary to use two different

forms of the model − one for each flow direction. Positive flow is described by the same model form as case

1 (eq. 3); negative flow is described by a form of the

model that allows for stage (water level) to be included

as a secondary variable. For case 2, the equation takes

the form:

. (4)

V Vi Xi Y ( ) + i

H

i = 1

n

= ∑ + C

V V = iXi + C

V Vi Xi Y = ( ) + i

H + C
14 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Equation 3 for positive flow is

solved using the same independent and

dependent variables as described in case 1.

To solve equation 4, a multivariate regression analysis is performed using Vi and the

product Vi × H as the independent variables, and V as the dependent variable. For

this model form, the relation established

between the index velocity and the mean

velocity is stable, but not constant for all

flow conditions because the slope of the

line varies with changing water level. Case

2 represents a velocity relation for which

every expected change in V for a unit

change in Vi also is dependent on the stage.

Flow conditions at West Highway

Creek resulted in a relation between acoustic line velocity and mean velocities, with

the use of equation 3 for positive flow and

equation 4 for negative flow. Computation

of mean velocity and discharge was performed using only the top (velocity no. 1)

acoustic velocity. The equation for velocity

no. 1 in the positive direction is V = 0.736

V1 − 0.013, with an R2 value of 0.962 and

a standard error for the velocity estimate of

0.048 ft/s. For negative flow, the equation

for velocity no. 1 is V = V1 (-0.921 +

1.094H) − 0.041, with an R2 value of 0.957

and a standard error for the velocity estimate of 0.034 ft/s. A comparison of results

obtained with and without the inclusion of

water level as a secondary variable in the

estimation model for velocities in the negative direction indicates that including the

secondary variable substantially improves

the R2 value and standard error. The R2

value increased from 0.759 to 0.957, and

the standard error decreased from 0.077 to

0.034 ft/s at West Highway Creek.

The relation obtained between the

mean measured velocity and estimated

velocity for West Highway Creek isshown

in figure 14 (using acoustic line velocity

no. 1). Figure 14 is not a rating of computed velocity as a function of acoustic line

velocity because the computed velocity is a

function of gage height as well as acoustic

line velocity. This plot shows actual measured mean velocitiesrelative to computed

-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

ADCP MEAN MEASURED VELOCITY, IN FEET PER SECOND

ACOUSTIC LINE VELOCITY, IN FEET PER SECOND

2.0

1.5

1.0

0.5

0

-0.5

-1.0

-1.5

V = 0.552 V1 - 0.016

R2 = 0.977

Measured

EXPLANATION

EXPLANATION

EXPLANATION

Measured

Measured

Calibration rating

Calibration rating

Calibration rating

ADCP mean measured velocity

ADCP mean measured velocity

ADCP mean measured velocity

ACOUSTIC LINE VELOCITY, IN FEET PER SECOND

1.5

1.0

0.5

0

-0.5

-1.0

-2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0

ACOUSTIC LINE VELOCITY, IN FEET PER SECOND

2.0

1.5

1.0

0.5

0

-0.5

-1.0

-1.5

McCormick Creek

V = 0.448 V1 - 0.024

V = 0.705 V2 - 0.031

R2 = 0.993

R2 = 0.995

Mud Creek

Trout Creek

V

V

V

V1

V1

V2

R2

R2

R2

ADCP

ADCP

ADCP

Acoustic Doppler Current Profiler

Acoustic Doppler Current Profiler

Acoustic Doppler Current Profiler

Coefficient of determination

Coefficient of determination

Coefficient of determination

Acoustic line velocity No. 1

Acoustic line velocity No. 1

Acoustic line velocity No. 2

-2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0

Figure 13.  Velocity relation for the McCormick Creek, Mud Creek, and

Trout Creek monitoring stations.
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 15

velocities in order to depict how the equation fits the

field measurements. The data used for the rating analysis, rated velocity and discharge, and residual values of

discharge are presented in the appendix.

Case 3

Case 3, used for Taylor River, describes the most

complex form of the velocity estimation model as

applied in the study. Due to the gage location at the

0.8

0.6

0.4

0.2

0

-0.2

-0.4

-0.6

ESTIMATED VELOCITY,

IN FEET PER SECOND

-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8

MEAN MEASURED VELOCITY, IN FEET PER SECOND

One to one line

EXPLANATION West Highway Creek

ADCP Acoustic Doppler Current Profiler

Acoustic line velocity No. 1

Acoustic line velocity No. 1 and stage

Figure 14.  Mean measured to estimated velocity relation for the West Highway Creek

monitoring station.

STREAMBED

FLOW LINES

ACOUSTIC VELOCITY

METER TRANSDUCER

CONFIGURATION

Water surface

Figure 15.  Complex flow characteristics with vertical circulation patterns

at the Taylor River monitoring station.

mouth of Taylor River, changes in width and depth of

flow, in combination with conditions caused by freshwater flowing out into more saline, denser water, can

create very distinct vertical and/or horizontal circulation patterns. Circulation patterns were found by

observing the velocity and salinity profile at Taylor

River. A generalized sketch of a vertical circulation pattern in relation to depths of recorded velocitiesisshown

in figure 15. The form of the model used assumes inclusion of multiple acoustic line velocities and

the relation of each to stage, as necessary,

to describe the mean velocity of the stream

due to the complex flow patterns at the site.

For this case, equation 2 takes the following form:

, (5)

where V1 is the acoustic line velocity from

the top path nearest to the watersurface, V2

is the acoustic line velocity from the middle path, V3 is the acoustic line velocity

from the bottom path nearest to the streambed, H is the stage, and Xi-3 and Yi-3 are

regression coefficients related to the acoustic path.

V V1 X1 Y ( ) + 1H V2 X2 Y = + ( ) + 2H

+ V3 X3 Y ( ) + 3H + C
16 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

To solve equation 5, it is necessary to perform a

multivariate regression analysis using acoustic velocities V1, V2, and V3 and the product of each velocity and

stage V1H, V2H, and V3H as the independent variables

with the mean measured velocity, V, as the dependent

variable. The relation established between the acoustic

line velocities and the mean velocity is less stable for

case 3 than for cases 1 and 2. Case 3 is used to describe

a relation between V and Vi (i = 1,2,3), with similarities

to the relation described for the negative portion of

case 2. Furthermore, every expected change in V for a

unit change in Vi for case 3 also depends on the stage,

where the main difference is that all three acoustic line

velocities are necessary to describe the system to the

best accuracy.

Velocity patterns at the mouth of Taylor River

present a circulation in the vertical plane; therefore, the

estimation model needs to include all three acoustic

line velocities as previously described. The vertical

velocity profile at this site is constantly changing

depending on the magnitude and direction of the flow,

the salinity of bay waters, and the stage at Taylor River.

These conditions at the mouth of Taylor River are characterized by localized bidirectional flow that exists for

extended periods caused by friction created in the water

column when outflowing freshwater rises above

denser, saltier, more saline bay water. Velocity

conditions, as shown in figure 15, describe those found

at the mouth of the creek where the instruments were

located. ADCP measurements used to calculate mean

measured velocities were made about 40 to 50 ft

upstream of the mouth where flow was uniform and

unidirectional from top to bottom. A good relation was

observed between the direction of V1 (top velocity) and

the direction of the net flow. Unlike the top velocity, V2

and V3 alternated between positive and negative values

depending on the direction and magnitude of the flow

and the water level in the bay. The velocity relation for

the Taylor River monitoring station is described by

V = V1 (0.231 + 0.665H) + V2 (0.375 − 0.202H) + V3

(0.377 − 0.407H) + 0.161, with an R2 value of 0.964

and a standard error of 0.085 ft/s. The relation of estimated velocity to mean measured velocity (using

velocity nos. 1, 2, and 3) is shown in figure 16. The

graph in figure 16 is not a rating of computed velocity

relative to acoustic line velocity because the computed

velocity is a function of gage height and acoustic line

velocity. This plot shows actual measured mean velocities relative to computed velocities and depicts how

the equation fits the field measurements. Data used for

the rating analysis, rated velocity and discharge, and

residual values of discharge are presented in the

appendix.

ESTIMATED VELOCITY,

IN FEET PER SECOND

MEAN VELOCITY, IN FEET PER SECOND

-0.5 0 0.5 1.0 1.5

1.5

1.0

0.5

0

-0.5

One to one line

EXPLANATION

ADCP Acoustic Doppler Current Profiler

ADCP mean measured velocity

Figure 16.  Mean measured to estimated velocity relation for the Taylor River monitoring

station.
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 17

The velocity relation improves significantly as

variables are added to the estimation model (table 2).

The velocity relation, which includes V1, V2, and H

(model form ì eî in table 2) was used for those periods

when bottom velocity was missing due to AVM

malfunctioning. Removing the bottom acoustic line

velocity variable resulted in an R2 value of 0.933 and a

standard error of 0.112 ft/s.

Estimated Flow at Noninstrumented Sites

It was not economically feasible to instrument all

streams or creeks discharging into northeastern Florida

Bay; therefore, alternatives were required to estimate

flow through the four noninstrumented sites (table 1).

The analysis performed in Long Sound at East Highway Creek, Oregon Creek, and Stillwater Creek used

15-minute discharge data from West Highway Creek as

the independent variable and instantaneous ADCP discharge measurements at the noninstrumented site asthe

dependent variable. Results of the analyses for determining discharge at these sites are presented in table 3.

The relation of flows between instrumented and noninstrumented sites varied with R2 values ranging from

0.865 to 0.99. The relation of discharge between West

Highway Creek and three of the noninstrumented sites

(Stillwater Creek, Oregon Creek, and East Highway

Creek) is shown in figure 17. Further investigation and

more data are needed to improve accuracy of records,

assess current flow conditions, and describe the distribution of freshwater flow in the Long Sound area.

Analyses were performed between measured

discharge at East Creek and computed discharge at

Taylor River and Mud Creek. Data from Mud Creek

showed the strongest relation to discharge measured at

East Creek and were used in the relation given in table

3 to calculate monthly discharges for East Creek. The

relation between measured discharge at East Creek and

computed simultaneous discharge at Taylor River (an

R2 value of 0.87) and Mud Creek (an R2 value of 0.98)

is shown in figure 18.

Table 2.  Different forms of the velocity estimation model tested for the Taylor River monitoring station

Model

form

Independent

variable Equation

Coefficient

of determination

(R2)

Standard error

(feet per

second)

a V1 V = 0.653 V1+ 0.087 0.615 0.271

b V2 V = 0.830 V2 - 0.024   .817   .186

c V3 V = 0.611 V3 + 0.569   .204   .389

d Vaverage V = 1.190 Vavg + 0.206   .896   .140

e V1, V2, H V = V1 (0.146 + 0.538H) + V2 (0.515 - 0.081H) + 0.018   .933   .112

f V1, V2, V3, H V = V1 (0.231 + 0.665H) + V2 (0.375 - 0.202H) +

       V3 (0.377 - 0.407H) + 0.161

  .964   .085

Table 3.  Results of correlation analyses for determining discharge at the East Highway Creek, Oregon Creek,

Stillwater Creek, and East Creek monitoring stations

[QWHWY is discharge value at West Highway Creek, and QMUD is discharge at Mud Creek]

Site name

Acoustic Doppler Current

Profiler measurements

Relation

Coeffcient

of determination

(R2)

Standard

error

(feet per

second)

Distance

from mouth

(feet)

Number of

measurements

East Highway Creek 150 17 Q = 0.521 QWHWY - 6.7 0.935 13.50

Oregon Creek 150 15 Q = 0.353 QWHWY + 0.57   .914 11.6

Stillwater Creek   50 15 Q = 0.347 QWHWY + 2.87   .865 15.89

East Creek   30 21 Q = 0.827 QMUD + 10.7   .99   9.68
18 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

y = 0.347x + 2.8735

R2 = 0.8654

-60

-40

-20

0

20

40

60

80

100

120

-200 -150 -100 -50 0 50 100 150 200 250 300

WEST HIGHWAY CREEK INSTANANEOUS

DISCHARGE, IN CUBIC FEET PER SECOND

y = 0.3526x + 0.5782

R2 = 0.9142

-40

-20

0

20

40

60

80

100

-150 -100 -50 0 50 100 150 200 250 300 350

WEST HIGHWAY CREEK INSTANTANEOUS

DISCHARGE, IN CUBIC FEET PER SECOND

y = 0.5214x - 6.7207

R2 = 0.9355

WEST HIGHWAY CREEK INSTANTANEOUS

DISCHARGE, IN CUBIC FEET PER SECOND

ADCP DISCHARGE, IN CUBIC FEET PER SECOND

-100

-50

0

50

100

150

-150 -100 -50 0 50 100 150 200 250 300

Oregon Creek

East Highway Creek

Stillwater Creek

Figure 17.  Relation of discharge between the West Highway Creek monitoring

station (instrumented site) and the Stillwater Creek, Oregon Creek, and East

Highway Creek monitoring stations (noninstrumented sites). R2 is coefficient of

determination, and ADCP is Acoustic Doppler Current Profiler.
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 19

Discharge Analysis and General Streamflow

Characteristics

As previously described, velocity and area relations developed for each site were used to calculate discharge time-series data for all monitoring stations

along the northeastern coastline of Florida Bay. Signatures of ebb and flood tides at these sites are either nonexistent or substantially dampened by: (1) a large

number of carbonate mud banks that divide Florida

Bay into a series of basins, (2) US-1 along the Florida

Keys, and (3) regional wind forces (Davis and Ogden,

1997). In the study area, the flow direction is mainly

dictated by the wet or dry conditions of the Everglades

wetlands and regional wind speed and direction. As a

result, commonly used data filters were not used to

extract tidal influence for net-flow calculations, but

rather, mean monthly discharge values were used

instead to account forstorage and to represent net flows

for all sites.

Seasonal Flow Patterns

Discharge data were collected to analyze seasonal flow patterns at the creeksin northeastern Florida

Bay. The period of record was from October 1995

through September 1999 and included extreme weather

events, such as the effects of El NiÒo of 1998. For comparison purposes, data were interpreted under wetseason (May to October) and dry-season (November to

April) conditions.

160

120

80

40

0

-40

-80

COMPUTED DISCHARGE,

IN CUBIC FEET PER SECOND

-80 -40 0 40 80 120 160

MEASURED DISCHARGE, IN CUBIC FEET PER SECOND

One to one line

Mud Creek Equation

EXPLANATION

Discharge relation between East Creek and Mud Creek

Discharge relation between East Creek and Taylor River

y = 0.827x + 10.7

y=0.760x - 7.0

R2 = 0.98

R2 = 0.87

Taylor River Equation

Figure 18.  Relation of discharge between the East Creek monitoring station (noninstrumented

site) and the Taylor River and Mud Creek monitoring stations (instrumented sites). R2 is

coefficient of determination.
20 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Total seasonal discharge records indicate that

about 80 percent of the total freshwater entering northeastern Florida Bay occurs during the wet season. The

mean freshwater discharge for all five instrumented

sites during the wet season from 1996 to 1999 is

106 ft3/s (cubic feet per second) . The wet season usually begins with an abrupt decrease in salinity along the

mangrove zone. This dry-to-wet season transition is

present at all sites and is shown for Taylor River in figure 19. Discharges for all five instrumented sites (West

Highway Creek, Trout Creek, Mud Creek, Taylor

River, and McCormick Creek) over various wet- and

dry-season periodsfrom 1996 to 1999 are shown in figure 20. Results indicate that the El NiÒo event had a

substantial effect on the magnitude of dry-season freshwater discharges, while having a negligible effect on

wet-season flows. The mean freshwater discharge of

55.6 ft3/s for all five instrumented sites during the

1997-98 dry season (fig. 20B) represents a 654 percent

increase compared to mean dry-season flows of

8.5 ft3

/s during the previous year (fig. 20A). Throughout the monitoring period (1996-99), the mean monthly

wetseason (May-October) flow at Trout Creek is about

340 ft3

/s, compared to 55 ft3/s at West Highway Creek,

52 ft3/s at Taylor River, 49 ft3/s at Mud Creek, and

33 ft3/s at McCormick Creek.

Spatial Distribution of Freshwater Flow and

Salinity

Calculated and estimated discharge data for the

monitoring stations in the study area were used to

describe the spatial distribution of flow into northeastern Florida Bay. Discharge into northeastern Florida

Bay is greatest in Trout Creek, with about 50 percent of

the total calculated freshwater flow. Thus, Trout Creek

is the main artery connecting this area of the bay to

Taylor Slough and the C-111 Canal. The percentage

distribution of total freshwater flow for the monitoring

stations in northeastern Florida Bay from March 1996

through September 1999 is shown in figure 21. Overbank flow is excluded because of a lack of available

data; however, overbank flow is negligible or nonexistent most of the time. Mean monthly flows and salinity

values were also compared to describe similarities (or

lack thereof) between the instrumented sites as shown

in figure 22.

250

200

150

100

50

0

-50

-100

-150

30

25

20

15

10

5

0

DATE

DISCHARGE, IN CUBIC

FEET PER SECOND

SALINITY, IN PARTS PER THOUSAND

06/01/97 06/06/97 06/11/97 06/16/97 06/21/97 06/26/97 07/01/97

Discharge

EXPLANATION

Salinity

Figure 19.  Brackish water (dry season) to freshwater (wet season) transition at the

Taylor River monitoring station.
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 21

SEASONAL FLOWS

MAY 1997 TO APRIL 1998

Wet season (May-October)

Dry season (November-April)

EXPLANATION

EXPLANATION

SEASONAL FLOWS

MAY 1996 TO APRIL 1997

200

150

100

50

0

-50

MEAN DISCHARGE, IN CUBIC FEET PER SECOND

McCormick

Creek

Taylor

River

Mud

Creek

Trout

Creek

West Highway

Creek

McCormick

Creek

Taylor

River

Mud

Creek

Trout

Creek

West Highway

Creek

McCormick

Creek

Taylor

River

Mud

Creek

Trout

Creek

West Highway

Creek

EXPLANATION

Wet season (May-October)

Dry season (November-April)

SEASONAL FLOWS

MAY 1998 TO APRIL 1999

A

B

C

500

400

300

200

100

0

-100

500

400

300

200

100

0

-100

Wet season (May-October)

Dry season (November-April)

Figure 20.  Wet- and dry-season freshwater discharges for the

McCormick Creek, Taylor River, Mud Creek, Trout Creek, and

West Highway Creek monitoring stations, May 1996 to April 1999.
22 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

               

Mud Creek (6%)

East Creek (8)*

Taylor River (8%)

McCormick Creek (3%)

Stillwater Creek (5%)*

Oregon Creek (4%)*

West Highway Creek (12%)

East Highway Creek (4%)*

Trout Creek (50%)

Figure 21.  Percentage distribution of total

freshwater discharge for the Florida Bay

monitoring stations, May 1996 to September

1999. Asterisk indicates estimated value.

McCormick Creek

EXPLANATION

Taylor River

Mud Creek

Trout Creek

West Highway Creek

McCormick Creek

EXPLANATION

Taylor River

Mud Creek

Trout Creek

West Highway Creek

MEAN DISCHARGE, IN CUBIC

FEET PER SECOND

MEAN MONTHLY SALINITY, IN

PARTS PER THOUSAND

1,000

800

600

400

200

0

-200

-400

Oct Feb Jun Oct Feb Jun Oct Feb Jun Oct Feb Jun Oct

Oct Feb Jun Oct Feb Jun Oct Feb Jun Oct Feb Jun Oct

1995

1995

1996

1996

1997

1997

1998

1998

1999

1999

DATE

DATE

B

45

40

35

30

25

20

15

10

5

0

A

Figure 22.  Mean monthly flows and salinity values for the McCormick

Creek, Taylor River, Mud Creek, Trout Creek, and West Highway Creek

monitoring stations, October 1995 through September 1999.

Results indicate three major flow

signatures at monitoring stationsfrom east

to west. They include the pattern exhibited

by West Highway Creek, which rarely

shows monthly net-negative flow; Trout

Creek, which shows the largest magnitudes of flow; and McCormick Creek,

which drifted from the rest of the stations,

showing net-negative flows (decline of

freshwater flows) toward the Monroe

Lake area at the start of the El NiÒo event

in June 1997 (fig. 22A). Discharge at

McCormick Creek deviates from all other

sites, resulting in an increase of negative

(inland) flow at this site during a period of

net positive freshwater outflow at all other

stations beginning in November 1997.

Analysis of regional wind patterns and

water levels in the Everglades wetlands

along Taylor Slough during the El NiÒo

dry season may help explain flow patterns

in McCormick Creek during the period.

Mean monthly salinity values also indicate major flow signatures as shown in

figure 22B. McCormick Creek maintains

the highest salinity of the instrumented

sites, supporting the concept that flow in

the creek is sometimes separated or disconnected from Taylor Slough flows. In

contrast, Taylor River usually maintains

the lowest salinity. The rest of the instrumented sites share a similar salinity pattern over time (fig. 22B).
Computing Freshwater Flow from Estuarine Creeks into Florida Bay 23

The continued study of discharge and salinity in

the study area would be necessary to extend the analysis period beyond the influence of extreme hydrologic

events, such as El NiÒo, which occurred during the

study period. Further investigation would also provide

short-term (monthly and seasonal) and long-term flow

trends along the northeastern coastline of Florida Bay

during ongoing Everglades restoration changes.

Base-Gage Selection and Discharge Relation

An analysis of mean monthly discharge was used

as a base-gage selection process. Using only one monitoring station or ì base gage,î further analysis can be

made to determine whether changes in water-management practices affect freshwater flow into northeastern

Florida Bay. Trout Creek, having the largest magnitude

of flow, wasselected as the test base gage for the study.

The analysis was performed using mean monthly discharge values because these values account for any

upland flows (negative discharge) into storage and are

assumed to represent net flows. The relation of discharge between Trout Creek and four monitoring stations (McCormick Creek, Mud Creek, Taylor River,

and West Highway Creek) is shown in figure 23.

The separation of McCormick Creek discharges

from the rest of the monitoring stationsis evident in the

R2 value of 0.629 obtained for the discharge relation to

Trout Creek. A longer study period would be needed to

determine if this separation is only a short-term drift

caused by El NiÒo. When ignoring discharge data during the El NiÒo event, an R2 value of 0.807 is obtained.

MCCORMICK CREEK

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

TAYLOR CREEK

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

MUD CREEK

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

WEST HIGHWAY CREEK

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

-400 -200 0 200 400 600 800 1,000

-400 -200 0 200 400 600 800 1,000

TROUT CREEK,

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

TROUT CREEK,

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

TROUT CREEK,

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

TROUT CREEK,

MEAN MONTHLY DISCHARGE,

IN CUBIC FEET PER SECOND

200

150

100

50

0

-50

Before and during

“El Nino” event

y = 0.1693x - 27.362

R2 = 0.6292

y = 0.159x - 13.363

R2 = 0.8074

-200

-150

-100

-50

0

50

100

150

200

250

Mean monthly during low

wetland water levels

Mean monthly without low

wetland water levels

Rating (mean monthly)

EXPLANATION

Rating (mean monthly without

low wetland water levels)

ALL DATA

EXCLUDING LOW WETLAND

WATER-LEVEL DATA y = 0.1338x + 0.4548

R2 = 0.911

-60

-40

-20

20

40

60

80

100

120

140

0

-400 -200 0 200 400 600 800 1,000

140

120

100

80

60

40

20

0

-20

-40

EXPLANATION

Mean monthly

Rating (mean monthly)

y = 0.1183x + 10.207

R2 = 0.8073

EXPLANATION

EXPLANATION

Mean monthly

Mean monthly

Rating (mean monthly)

Rating (mean monthly)

y = 0.1416x + 18.014

R2 = 0.8874

-400 -200 0 200 400 600 800 1,000

Figure 23.  Relation of discharge between Trout Creek and other selected monitoring stations in northeastern Florida

Bay. R2 is coefficient of determination.
24 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Additionally, even though the relation between Trout

Creek and West Highway Creek is high with an R2

value of 0.887, continued monitoring of flows into

Long Sound would be needed to determine the effects

of planned restoration changes in the C-111 Canal.

Trout Creek and Mud Creek show the highest relation

with an R2 value of 0.911, whereas Trout Creek and

Taylor River have an R2 value of 0.807. These analyses

indicate that Trout Creek could potentially be used as a

long-term monitoring station, provided that the aforementioned questionsregarding flow patterns at McCormick Creek and those into Long Sound can be resolved.

Regardless of flow patterns, however, changes in

water-delivery management practices over the course

of the Everglades restoration process could substantially alter flow characteristics of the creeks from

present-day conditions.

SUMMARY AND CONCLUSIONS

Restoration of the Florida Bay ecosystem

requires an understanding of the linkage between the

amount of freshwater flowing into the bay and the

salinity of the bay environment. A study was conducted

at nine monitoring stationsto estimate freshwater flows

from the mainland into Florida Bay. Data collected

from the monitoring stations in estuarine creeks

included water level, acoustic line velocity, salinity,

and temperature. Velocity ratings along with crosssectional areas were developed to calculate discharge.

The discharge data were used to analyze seasonal flow

patterns and to describe the spatial distribution of freshwater flow and salinity. Additionally, an analysis of

discharge was used as a base-gage selection process to

determine whether one monitoring station could indicate how changes in water-management practices can

affect freshwater flow into northeastern Florida Bay.

The technique used to describe the relation of

acoustic line velocity to mean velocity is a leastsquares

regression model in the single or multiple variable

form. Three forms of an equation were required to

describe flow patterns at five instrumented sites (West

Highway Creek, Trout Creek, Mud Creek, Taylor

River, and McCormick Creek). For the acoustic-tomeasured velocity relation, R2 values ranged from

0.977 to 0.995 at three of the sites (Trout Creek, Mud

Creek, and McCormick Creek). In calculating discharge for positive and negative flow, the R2 values

were 0.962 and 0.957, respectively, at West Highway

Creek. When using the most complex form of the

model to calculate discharge, the R2 value was 0.964

with a standard error of 0.085 ft/s at Taylor River.

Removing an acoustic velocity variable from the equation resulted in an R2 value of 0.933 and a standard

error of 0.112 ft/s at the same site.

To gain a better understanding of freshwater

flows into Florida Bay, discharge at noninstrumented

sites were considered. These noninstrumented sites

include East Highway Creek, Oregon Creek, Stillwater

Creek, and East Creek. Techniques were used to establish relations between discharge at each of these sites

and discharge at a nearby instrumented site. For the

sitesin Long Sound (East Highway Creek, Oregon, and

Stillwater Creeks), an analysis was performed using

15-minute discharge from nearby West Highway

Creek. For East Creek in Little Madiera Bay, an analysis was performed using 15-minute discharge data from

nearby Mud Creek and Taylor River. The strongest

relation was between East Creek and Mud Creek. More

data collected at new and existing monitoring stations

could improve the accuracy of the records and provide

a better description of the distribution of freshwater

flow in Long Sound.

Flows in the streams along the northeastern

coastline of Florida Bay do not present the typical ebb

and flood tidal signatures of most estuarine streams.

These tidal signatures are either nonexistent or

substantially dampened by the large number of mud

banks that divide Florida Bay into a large number of

sub-basins by U.S. Highway 1 along the Florida Keys,

and by regional wind forces. Analysis of seasonal

flowsindicate that about 80 percent of the annual freshwater entry to northeastern Florida Bay occurs during

the wet season (May-October), with a sharp and

distinct transition from brackish to freshwater at the

start of the wet season. The effect of El NiÒo on dryseason flows are evidenced by a substantial increase in

mean dry-season discharge at the monitoring stations

from 8.5 ft3

/s in the 1996-97 season to 55.6 ft3/s.

Regional wind patterns and shallow depth in the Everglades wetlands following El NiÒo also are the probable cause for a divergence in flow pattern between

McCormick Creek and the rest of the monitoring

stations in the area during this period.

Three main flow signatures were identified when

comparing flows at all monitoring stations, with the

mostsignificant one being the magnitude of discharges

at Trout Creek, which carries about 50 percent of the

total measured freshwater entering northeastern
References Cited 25

Florida Bay. The other two main signatures are the drifting of flowsin McCormick Creek to the north following

the El NiÒo event and the absence of net negative flows

at West Highway Creek. The observed east-to-west flow

distribution, and especially the magnitude of flows

through Trout Creek in comparison with the other

creeks, suggests that overall flow of freshwater in the

Everglades wetlands along Taylor Slough may be

directed farther eastward than previously thought.

Trout Creek was the base gage selected for

analysis and used to determine if one station could indicate how changesin water-management practices on the

mainland may affect freshwater flows into northeastern

Florida Bay. Analyses indicate that Trout Creek could

potentially be used as the long-term monitoring station,

provided that questions regarding the flow patterns at

McCormick Creek and Long Sound streams are

answered and that flow characteristics do not change

substantially.

REFERENCES CITED

Davis, S.M., and Ogden, J.C., 1997, Everglades, the ecosystem and itsrestoration: Boca Raton, Fla., St. Lucie Press,

826 p.

Laenen, Antonious, and Curtis, R.E., 1989, Accuracy of

acoustic velocity metering systems for measurement of

low velocity in open channels: U.S. Geological Survey

Water-Resources Investigations Report 89-4090, 15 p.

Laenen, Antonius, and Smith, Whinchell, 1983, Acoustic systemsfor the measurement ofstreamline: U.S. Geological

Survey Water-Supply Paper 2213, 26 p.

Patino, Eduardo, and Ockerman, Darwin, 1997, Computation

of mean velocity in open channels using acoustic velocity meters: U. S. Geological Survey Open-File Report

97-220, 12 p.

RD Instruments, 1989, Acoustic Doppler Current Profilers −

Principles of operation: A practical primer: San Diego,

Calif., RD Instruments Publications, 36 p.

Regan, R., and Schaffranek, R.W., 1985, A computer program for analyzing channel geometry: U.S. Geological

Survey Water-ResourcesInvestigations Report 85-4335,

49 p.
26 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay
Appendix 27

APPENDIX

Data Set Used to Develop Velocity Relations for the

Monitoring Stations

[Velocity no. 1 is the acoustic line velocity from the top AVM path nearest to the water surface; velocity no. 2 is

the acoustic line velocity from the middle AVM path; and velocity no. 3 is the acoustic line velocity from the

bottom AVM path nearest to the streambed. Abbreviations: AVM, acoustic velocity meter; ft, feet; ft/s, feet per

second; ft2

, square feet; ft3/s, cubic feet per second; -- not used or not applicable]
28 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

McCormick Creek

Measurement

No.

Date

Measured

discharge

(ft3/s)

Velocity

no. 1

(ft/s)

Stage

(ft)

Rated

area

(ft2)

Measured

velocity

(ft/s)

Rated

velocity

(ft/s)

Rated

discharge

(ft3/s)

Residuals

(ft3/s)

  1

01-15-96

    48.2   0.42 -0.88 223.8   0.22 0.22     48.4    0.2

  2     49.7     .42 -.88 223.8     .22   .22     48.4   -1.3

  3     52.3     .42 -.88 223.8     .23   .22     48.4   -3.9

  4     49.5     .43 -.88 223.8     .22   .22     49.5      .1

  5     47.6     .43 -.88 223.8     .21   .22     49.5    2.0

  6     51.5     .43 -.88 223.8     .23   .22     49.6   -1.9

  8

02-02-96

-172.2    -.92 -.42 254.1    -.68 -.52 -133.2 39.0

  9 -169.9    -.92 -.42 254.1    -.67 -.52 -133.2 36.7

10 -141.3    -.92 -.42 254.1    -.56 -.52 -133.2    8.1

11 -165.0    -.92 -.42 254.1    -.65 -.52 -133.2 31.8

12 -147.2    -.92 -.41 254.8    -.58 -.52 -133.5 13.7

13 -149.9    -.92 -.41 254.8    -.59 -.52 -133.5 16.4

14 -165.5    -.92 -.41 254.8    -.65 -.52 -133.5 32.0

15 -147.7    -.92 -.41 254.8    -.58 -.52 -133.5 14.2

16

03-18-96

-145.5 -1.24 -.24 266.0    -.55 -.70 -186.4 -40.9

18 -159.7 -1.21 -.23 266.7    -.60 -.68 -182.5 -22.8

20 -147.4 -1.21 -.23 266.7    -.55 -.68 -182.5 -35.1

21 -146.4 -1.25 -.22 267.3    -.55 -.71 -188.8 -42.4

22 -149.3 -1.25 -.22 267.3    -.56 -.71 -188.8 -39.5

23

06-11-96

    74.3     .56 -.50 248.9     .30   .29     73.1   -1.2

24     76.2     .56 -.50 248.9     .31   .29     73.1   -3.1

25     69.9     .56 -.50 248.9     .28   .29     73.1   3.2

26     76.1     .56 -.50 248.9     .31   .29     73.1   -3.0

27     75.4     .65 -.50 248.9     .30   .34     85.4 10.0

28     67.2     .65 -.50 248.9     .27   .34     85.4 18.2

29     70.6     .65 -.50 248.9     .28   .34     85.4 14.8

30     69.8     .65 -.50 248.9     .28   .34     85.4 15.6

31

10-20-96

  214.3   1.19 .07 286.5     .75   .64   183.8 -30.5

32   197.2   1.19 .07 286.5     .69   .64   183.8 -13.4

33   171.5   1.15 .08 287.1     .60   .62   177.8    6.3

34   193.1   1.12 .08 287.1     .67   .60   173.1 -20.0

35   174.7   1.12 .08 287.1     .61    .60   173.1   -1.6

37

11-20-96

-138.9    -.80 -.25 265.4    -.52 -.46 -121.5 17.4

38 -145.0    -.81 -.25 265.4    -.55 -.46 -123.0 22.0

39 -114.2    -.81 -.25 265.4    -.43 -.46 -123.0   -8.8

40

11-20-96

-156.2    -.81 -.25 265.4    -.59 -.46 -123.0 33.2

41 -139.2    -.81 -.25 265.4    -.52 -.46 -123.0 16.2

42 -134.5    -.83 -.25 265.4    -.51 -.47 -125.9    8.6

43 -137.7    -.83 -.25 265.4    -.52 -.47 -125.9 11.8

44 -136.9    -.83 -.25 265.4    -.52 -.47 -125.9 11.0

46

12-17-96

   -96.7    -.86 -.56 244.9    -.39 -.49 -120.2 -23.5

47    -92.7    -.86 -.56 244.9    -.38 -.49 -120.2 -27.5

48    -87.9    -.84 -.55 244.9    -.36 -.48 -117.5 -29.6

49    -88.5    -.84 -.55 244.9    -.36 -.48 -117.5 -29.0

50

06-12-97

  308.3   1.80 .50 315.7     .98   .98 308.9     .6

51   319.7   1.80 .50 315.7   1.01   .98 308.9 -10.8

53   325.6   1.88 .50 315.7   1.03 1.02 322.9   -2.7
Appendix 29

Mud Creek

Measurement

No.

Date

Measured

discharge

(ft3/s)

Velocity

no. 1

(ft/s)

Stage

(ft)

Rated

area

(ft2)

Measured

velocity

(ft/s)

Rated

velocity

(ft/s)

Rated

discharge

(ft3/s)

Residuals

(ft3/s)

  1

12-08-95

-32.1 -0.42 -0.72 145.3 -0.22 -0.21 -31   -1

  2 -33.6   -.42 -.72 145.3    -.23   -.21 -31   -3

  3 -36.6   -.48 -.72 145.3    -.25   -.24 -35   -2

  4 -37.9   -.48 -.72 145.3    -.26   -.24 -35   -3

  5 -34.7   -.48 -.72 145.3    -.24   -.24 -35     0

  6 -33.5   -.37 -.71 145.6    -.23   -.19 -27   -6

  7 -31.5   -.37 -.71 145.6    -.22   -.19 -27   -4

  8 -36.3   -.39 -.72 145.3    -.25   -.20 -29   -8

  9 -30.2   -.39 -.72 145.3    -.21   -.20 -29   -2

10

01-13-96

76.2 1.23 -1.12 130.9     .58     .53 69     7

11 71.0 1.23 -1.12 130.9     .54     .53 69     2

12 70.7 1.23 -1.12 130.9     .54     .53 69     2

13 71.9 1.23 -1.12 130.9     .55     .53 69     3

14 82.7 1.46 -1.19 128.4     .64     .63 81     2

15 83.4 1.46 -1.19 128.4     .65     .63 81     3

16 77.9 1.46 -1.19 128.4     .61     .63 81   -3

17 79.9 1.53 -1.18 128.7     .62     .66 85   -5

18 82.1 1.53 -1.18 128.7     .64     .66 85   -3

19 69.2 1.26 -1.16 129.4     .53     .54 70   -1

20 73.4 1.26 -1.16 129.4     .57     .54 70     4

21 80.2 1.34 -1.13 130.5     .61     .58 75     5

22

01-14-96

-23.3 -.43 -.91 138.4   -.17   -.22 -30     6

23 -20.7 -.43 -.91 138.4   -.15   -.22 -30     9

24 -25.1 -.43 -.91 138.4   -.18   -.22 -30     5

25

02-01-96

-44.8 -.68 -.70 146.0   -.31   -.33 -48     3

26 -47.5 -.68 -.70 146.0   -.33   -.33 -48     0

27 -44.0 -.68 -.70 146.0   -.30   -.33 -48     4

28 -44.4 -.68 -.70 146.0   -.30   -.33 -48     3

29

03-20-96

64.0 1.02 -.55 151.4    .42    .43 66   -2

30 32.7    .69 -.50 153.2    .21    .29 44 -11

31

04-11-96

17.7   .37 -.84 141.0    .13    .14 20   -2

32 16.4   .37 -.84 141.0    .12    .14 20   -4

33 20.6   .37 -.84 141.0    .15    .14 20     1

34 16.5   .37 -.84 141.0    .12    .14 20   -4

35 18.8   .37 -.84 141.0    .13    .14 20   -1
30 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Trout Creek

Measurement

No.

Date

Measured

discharge

(ft3/s)

Velocity

no. 1

(ft/s)

Stage

(ft)

Rated

area

(ft2)

Measured

velocity

(ft/s)

Rated

velocity

(ft/s)

Rated

discharge

(ft3/s)

Residuals

(ft3/s)

29

05-16-96

     111.3 -- -1.04 493   0.225 0.254   125   14.19

31     109.5 -- -1.04 493     .222   .254   125   19.55

32      111.6 -- -1.04 493     .226   .254   125   13.89

43

06-12-96

    547.1 -- -.68 538   1.047   .992   519 -28.37

44     483.6 -- -.68 538     .925   .992   519   35.13

47     662.4 -- -.69 536   1.270 1.141   595 -67.15

48     621.5 -- -.68 538   1.189 1.113   582 -39.67

49     608.2 -- -.68 538   1.163 1.085   567 -41.21

50     625.3 -- -.68 538   1.196 1.085   567 -58.31

51     523.9 -- -.69 536   1.005 1.007   525     1.00

52     507.4 -- -.69 536     .973 1.007   525   17.50

53     544.6 -- -.67 539   1.039   .943   494 -50.68

54     520.2 -- -.67 539     .993   .943   494 -26.28

55

07-18-96

    539.3 -- -.98 500   1.110 1.070   520 -19.43

56     530.8 -- -.98 500   1.093 1.070   520 -10.93

57     307.9 -- -.94 505     .628   .694   340   32.60

58     356.0 -- -.94 505    .726   .701   344 -12.02

59     437.5 -- -.95 504     .894   .751   367 -70.05

60     359.6 -- -.95 504     .735   .751   367     7.85

61

08-14-96

    101.2 -- -.82 520     .195   .247   128   27.21

62        91.3 -- -.82 520     .175   .247   128   37.11

64      -33.6 -- -.82 520   -.065   -.087    -45 -11.61

67      -52.0 -- -.82 520   -.100   -.101    -53    -.60

68    -133.3 -- -.82 520   -.256   -.215 -112 21.60

69    -137.9 -- -.82 520   -.265   -.215 -112 26.20

70

08-14-96

   -226.6 -- -.82 520   -.436   -.463 -241 -14.39

71    -229.1 -- -.82 520   -.440   -.463 -241 -11.89

72    -254.7 -- -.82 520   -.490   -.548 -285 -30.62

73    -263.7 -- -.82 520    -.507   -.548 -285 -21.62

74

10-20-96

1,091.0 -- -.07 615   1.774 1.823 1,121   30.44

75 1,070.7 -- -.07 615   1.741 1.823 1,121   50.74

76 1,087.3 -- -.06 616   1.764 1.816 1,119   32.09

77 1,068.3 -- -.06 616   1.733 1.809 1,115   46.72

78 1,102.1 -- -.06 616   1.788 1.802 1,111     8.54

79 1,047.8 -- -.06 616   1.700 1.795 1,106   58.46

80

11-19-96

-625.3 -- -.39 574 -1.089 -1.031 -592   33.18

81 -637.0 -- -.39 574 -1.109 -1.038 -596   40.81
Appendix 31

West Highway Creek

Measurement

No.

Date

Measured

discharge

(ft3/s)

Velocity

no. 1

(ft/s)

Stage

(ft)

Rated

area

(ft2)

Measured

velocity

(ft/s)

Rated

velocity

(ft/s)

Rated

discharge

(ft3/s)

Residuals

(ft3/s)

  7

03-20-96

    -49 -0.29 -0.72 283 -0.173 -0.165 -47     2

  8     -42   -.29 -.72 283   -.149 -.165 -47   -5

10     -28   -.06 -.70 284   -.098 -.068 -19     9

1g

04-12-96

    -29   -.09 -.86 274   -.107 -.066 -18   11

2g     -14   -.09 -.86 274   -.052 -.066 -18   -4

3g        5    .14 -.86 274    .018   .090   25   20

4g        3    .14 -.86 274    .011   .090   25   22

5g       -1    .04 -.85 274   -.003   .017     5     5

6g      11    .04 -.85 274    .040   .017     5   -7

11

05-17-96

     43    .21 -1.04 261    .165   .142   37   -6

12      50    .21 -1.04 261    .192   .142   37   13

13      45    .21 -1.04 261    .173   .142   37   -8

13      46    .21 -1.04 261    .176   .142   37   -9

15      29    .10 -1.04 261     .111   .061   16 -13

16      17    .10 -1.04 261    .064   .061   16   -1

17     -10   -.02 -1.03 262    -.038 -.043 -11   -1

18     -11   -.02 -1.03 262    -.040 -.043 -11   -1

19     -10   -.02 -1.03 262    -.037 -.043 -11   -2

34

10-21-96

   181    .72 .21 348    .521   .517 180   -1

35    190    .72 .21 348    .546   .517 180 -10

36    227    .80 .21 348    .652   .576 200 -26

37    208    .80 .21 348    .597   .576 200   -8

38

11-18-96    176    .77 .10 340    .518   .554 188   12

39    179    .77 .10 340    .525   .554 188   10

40

11-21-96

   161    .77 .10 340    .472   .554 188   28

41 -122   .31 -.11 325   -.375 -.380 -124   -2

42 -109 -.31 -.11 325   -.336 -.380 -124 -14

43 -142 -.30 -.11 325   -.437 -.369 -120   22

44 -116    .30 -.11 325   -.355 -.369 -120   -5

45

12-16-96     12    .12 -.67 286   .043   .075   22     9

46      -9 -.06 -.67 286 -.030 -.070 -20 -11
32 Freshwater Flow from Estuarine Creeks into Northeastern Florida Bay

Taylor River

Measurement

No.

Date

Measured

discharge

(ft3/s)

Velocity

no. 1

(ft/s)

Velocity

no. 2

(ft/s)

Velocity

no. 3

(ft/s)

Stage

(ft)

Rated

area

(ft2)

Measured

velocity

(ft/s)

Rated

velocity

(ft/s)

Rated

discharge

(ft3/s)

Residuals

(ft3/s)

  4

12-08-95

  32.6 0.50 0.76 -0.72 -0.70 80.58 0.405 0.436    35   -3

  5   37.7    .50 .76 -.72 -.70 80.58   .468   .436    35     3

  6   35.6    .50 .76 -.72 -.70 80.58   .442   .436    35     0

  7   31.3    .50 .76 -.72 -.70 80.58   .388   .436    35   -4

  8   33.4    .46 .69 -.71 -.69 80.76   .414   .404    33     1

  9   34.2    .46 .69 -.71 -.69 80.76   .423   .404    33     2

10

01-14-96

  22.2    .89 .13 -.70 -.85 77.88   .285   .287    22   -0

11   26.5    .89 .13 -.70 -.85 77.88   .340   .287    22     4

12   27.8    .89 .13 -.70 -.85 77.88   .357   .287    22     5

13   26.4    .89 .13 -.70 -.85 77.88   .339   .287    22     4

14   24.3    .89 .13 -.70 -.85 77.88   .312   .287    22     2

15   28.2    .89 .13 -.70 -.85 77.88   .362   .287    22     6

16   22.6    .89 .13 -.70 -.85 77.88   .290   .287    22     0

17

01-15-96

  27.6    .74 .58 -.78 -.89 77.16   .358   .338    26     2

18   21.8    .74 .58 -.78 -.89 77.16   .283   .338    26   -4

19   26.1    .74 .58 -.78 -.89 77.16   .338   .338    26     0

20   24.4    .74 .58 -.78 -.89 77.16   .316   .338    26   -2

21

02-02-96

-38.8 -.80 -.02 -.59 -.44 85.40 -.454 -.419 -36   -3

22 -36.1 -.80 -.02 -.59 -.44 85.40 -.423 -.419 -36   -0

23 -37.2 -.80 -.02 -.59 -.44 85.40 -.436 -.419 -36   -1

24

02-08-96

  15.0    .42 .20 -.38 -1.02 74.80   .200   .185 14     1

25   16.5    .42 .20 -.38 -1.02 74.80   .221   .185 14     3

26   14.7    .42 .20 -.38 -1.02 74.80   .196   .185 14     1

30

04-11-96

  21.7    .11 .51 -.09 -.79 78.96   .275   .345 27   -6

31   20.4    .11 .51 -.09 -.79 78.96   .258   .345 27   -7

32   21.9    .11 .51 -.09 -.79 78.96   .277   .345 27   -5

33   20.8    .11 .51 -.09 -.79 78.96   .263   .345 27   -6

39 05-16-96   14.9    .17 .40 -.20 -.91 76.80   .194   .286 22   -7

40   15.2    .17 .40 -.20 -.91 76.80   .198   .286 22   -7

42

05-16-96

  12.6    .14 .38 -.32 -.88 77.34   .163   .234 18   -5

43   11.4    .14 .38 -.32 -.88 77.34   .147   .234 18   -7

44   10.3    .14 .38 -.32 -.88 77.34   .133   .234 18   -8

49

06-11-96

  26.0    .21 .66 .02 -.62 82.02   .317   .463 38 -12

50   31.1    .21 .66 .02 -.62 82.02   .379   .463 38   -7

51   33.0    .21 .66 .02 -.62 82.02   .402   .463 38   -5

52   29.4    .21 .66 .02 -.62 82.02   .358   .463 38   -9

61

07-18-96

  82.1    .63 1.07 .41    -.82 78.42 1.047   .869   68 14

62   83.0    .63 1.07 .41 -.82 78.42 1.058   .869   68 15

63   84.5    .63 1.07 .41 -.82 78.42 1.078   .869   68 16

70   14.4    .61 -.04 -.61 -.78 79.14   .182   .209   17 -2

71   13.7    .61 -.04 -.61 -.78 79.14   .173   .209   17 -3

82     7.9    .42 -.17 -.63 -.75 79.68   .099   .105     8 -0

73     6.7    .42 -.17 -.63 -.75 79.68   .084   .105     8 -2

74   -1.5    .26 -.12 -.58 -.73 80.04 -.019   .078     6 -8

75       .5    .26 -.12 -.58 -.73 80.04   .006   .078     6 -6

76   -3.1    .12 -.15 -.46 -.72 80.22 -.039   .045     4 -7

77   -2.6    .12 -.15 -.46 -.72 80.22 -.032   .045     4 -6

78 -14.0   -.57 -.15 -.65 -.70 80.58 -.174 -.299 -24 10

79 -11.1   -.57 -.15 -.65 -.70 80.58 -.138 -.299 -24 13

80 -14.3   -.51 -.25 -.66 -.69 80.76 -.177 -.307 -25 10

81 -13.0   -.51 -.25 -.66 -.69 80.76 -.161 -.307 -25 12

82 -15.7   -.51 -.25 -.66 -.69 80.76 -.194 -.307 -25 9

83 -15.3   -.51 -.25 -.66 -.69 80.76 -.189 -.307 -25 9

84

10-20-96

105.2     .90 1.27   -.4 -.06 93.00 1.131 1.174 109 -4

85 119.2     .90 1.27   -.4 -.06 93.00 1.282 1.174 109 10

86 102.7     .88 1.24 -.44 -.06 93.00 1.104 1.151 107 -4

87 113.1     .88 1.24 -.44 -.06 93.00 1.216 1.151 107 6

88 104.9     .88 1.24 -.44 -.06 93.00 1.128 1.151 107 -2

89 106.3     .88 1.24 -.44 -.06 93.00 1.143 1.151 107 -1

90 -34.0   -.57 -.23 -.93 -.09 92.40 -.368 -.366 -34 -0

91 -35.2   -.57 -.23 -.93 -.09 92.40 -.381 -.366 -34 -1

92 -38.5   -.57 -.23 -.93 -.09 92.40 -.417 -.366 -34 -5