Introduction 

 In southern Florida, water-management practices must support a large and rapidly growing urban population as well as 

intensive agricultural activities. However, these water management practices have altered the natural hydrology of the 

Everglades ecosystem, including Florida Bay and the estuaries 

along the southwestern coast of Florida. During the past few 

decades, the coastal environments of southern Florida have 

shown signs of ecological deterioration that may be attributed 

to changes in freshwater inflows and associated salinity and 

nutrient level increases in estuarine waters. With the goal of the 

Comprehensive Everglades Restoration Plan (CERP) to restore 

the quantity, timing, and distribution of freshwater flows within 

the Everglades to more natural conditions, changes are expected 

to occur in the major rivers 

and creeks flowing into 

the estuaries. However, 

substantial hydrologic 

information gaps exist 

throughout the Everglades 

wetlands and estuaries 

that need to be addressed 

for the restoration process 

to succeed. Specifically, 

hydrologic information 

throughout the Everglades 

and adjacent ecosystems is 

required for the development of restoration strategies and for future evaluation of restoration results. 

 To address these issues, 

the U.S. Geological Survey 

(USGS) began a series of 

studies in 1995 to monitor 

the major rivers and creeks 

that discharge freshwater 

into northeastern Florida 

Bay and the southwestern 

estuaries of Everglades 

National Park (ENP). 

These studies provide: 

(1) flow, salinity, water 

temperature, and water-

 U.S. Department of the Interior 

 U.S. Geological Survey 

 Fact Sheet 2004-3129

 November 2004 

 Hydrologic Characteristics of Estuarine River Systems within 

Everglades National Park 

Printed on recycled paper

level data for research applications including model development and calibration; and (2) supply base-line information 

for other physical, biological, and chemical studies being 

conducted in these areas. As part of these studies, a network of 

35 estuarine and wetland hydrologic monitoring stations (fig. 

1) has been constructed. Historical data for some locations are 

currently available through the USGS South Florida Information Access (SOFIA) web page at http://sofia.er.usgs.gov/, and 

real-time hydrologic information also is available at the USGS 

national water information systems website http://waterdata.

usgs.gov/fl/nwis/rt. These studies are funded in part by the 

USGS Greater Everglades Priority Ecosystem Science (PES) 

Program, which is an effort by the USGS to provide earth science information needed to resolve land-use and water issues. 

Additional support is provided by ENP, the South Florida Water 

Management District (SFWMD), and the U.S. Army Corps of 

Engineers (USACE). 

Figure 1. Location of U.S. Geological Survey estuarine and wetland hydrologic monitoring stations in Everglades 

National Park, South Florida.
 Monitoring Network and Products 

 The network of monitoring stations (fig. 1) collects 

information at points of interest that represent major flow 

paths from the Everglades wetlands to the estuaries. Combining data collected throughout the network assures that 

hydrologic information will be available (from upstream 

to downstream) across 10 generalized coastal gradients or 

river/creek systems (fig. 2). 

 In addition to data collected from the monitoring stations, 

moving boat surveys are performed along these 10 generalized transects to collect salinity, water temperature, and 

geographic location data. Results of a salinity survey made 

on March 30, 2004, are shown in figure 3 . Salinity is in parts 

per thousand (ppt).

Acoustic Doppler Velocity Measurements 

 Acoustic Doppler Velocity Meters (ADVMs) are used to 

collect time-series water-velocity data. Velocities measured 

by these units (index velocities) are directly proportional 

to the mean cross-sectional velocity for the stream, and are 

used in conjunction with Acoustic Doppler Current Profiler 

(ADCP) measurements to develop calibration ratings for the 

computation of discharge. Index velocity is the predominant 

variable, and in most instances, the only variable needed to 

describe the relation to the mean measured velocity. Stage is 

occasionally needed as a secondary variable, or “modifier” 

of the velocity relation. The relation between the ADVM 

index velocity (X axis) and the ADCP mean measured 

velocity (Y axis) developed for the Chatham River monitoring station is shown in figure 4. 

Figure 2. Monitoring stations located within 10 generalized coastal transects. 

Arrows represent coastal 

transects.

 Flow and Salinity Characteristics 

 Continuous salinity data from the main rivers and along 

transects from freshwater wetlands to estuaries will be useful for describing the spatial and temporal variation of salinity 

throughout the study area. The data also will help scientists 

and managers determine how salinity patterns may change in 

response to restoration efforts that affect freshwater deliveries 

to the Everglades. Figure 5 displays salinity patterns along the 

southwestern coast of ENP. 

 Trends in the magnitude and distribution of flows between 

creeks can readily be distinguished (fig. 6). Mean monthly 

values of discharge data for northeastern Florida Bay are shown 

in figure 6. Trends in the magnitude and distribution of flows 

between creeks are easily distinguishable. 

 Tools for Adaptive Management of Everglades 

Restoration 

 Assuming that CERP modifications to water-delivery systems will attempt to reproduce historical hydroperiods more 

effectively than existing water-management practices, it is 

reasonable to expect an extended hydroperiod and shortened 

dry season during years of average rainfall. Data have been 

collected from the network since 1995, during a period when 

the southern estuaries have experienced a wide range of natural 

climatic conditions, including multiple tropical storms and hurricanes, and an El Niño event in 1998. Thus, the data gathered 

from the monitoring stations can be used to help determine 

whether changes observed in the ecosystem are the result of 

natural processes, CERP-related activities, or a combination of 

both. 
Figure 3. Salinity survey made on March 31, 2004.

Figure 4. Velocity index rating for Chatham River (located north of Lostmans River).

 Benefits to CERP 

 Use of the historical and real-time data will benefit CERP in 

several ways: 

 • Pre-CERP (base line) hydrologic and water-quality parameters can be compared to data collected during and after 

CERP modifications, 

 • Scientific investigations can be conducted with physical data rather than theoretical values in order to increase 

ecosystem understanding, and 

 • Real-time and historical data can be used to detect unexpected responses within the ecosystem. 

 In summary, a monitoring network spanning the major flow 

paths from the Everglades wetlands to the southern estuaries 

will help provide a system-wide understanding of the ecosystem 

responses occurring in the Everglades due to changes in watermanagement practices and climatic variability. 

y = 0.7345x + 0.0864

R2= 0.994

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

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

INDEX VELOCITY VELOCITY, IN FEET PER SECOND , IN FEET PER SECOND

04/19/01

10/26/01

02/05/02

03/13/02

10/03/02

02/27/03

MEAN VELOCITY, IN FEET PER SECOND , IN 

F

EET PER SECO

N

D VELOCITY

EXPLANATION
Figure 5. Salinity values for selected rivers along the southwestern coast of Everglades National Park.

 For more information 

 Clinton Hittle

 U.S. Geological Survey Florida 

Integrated Science Center�Water 

and Restoration Studies 

 9100 N.W. 36 St. Ste. 110 

 Miami Fla., 33179 

 Phone (305) 717-5815 

 E-mail: cdhittle@usgs.gov 

 Eduardo Patino 

 U.S. Geological Survey Florida 

Integrated Science Center�Water 

and Restoration Studies 

 3745 Broadway, Ste. 301 

 Ft. Myers, Fla. 33901 

 (239) 275-8448 ext. 11 

 E-mail: epatino@usgs.gov 

 Mark Zucker 

 U.S. Geological Survey Florida 

Integrated Science Center�Water 

and Restoration Studies 

 9100 N.W. 36 St., Ste. 110 

Miami Fla., 33179 

 Phone (305) 717-5815 

 E-mail: mzucker@usgs.gov 

A

B

0

5

10

15

20

25

30

35

40

45

2/28 4/19 6/8 7/28 9/16 11/5 12/25 2/13 4/4 5/24 7/13

SALINITY, INPART

S

PER THOUSAND

North

River

Shark

River

Broad

River

Lostmans

River

0

5

10

15

20

25

30

35

40

45

SALINITY, INPART

S

PER THOUSAND

Bottle Creek at

Rookery Bay

Shark River ENP marker near

3/01 3/15 4/01 4/15 5/01 5/15 6/01 6/15 7/01 7/15 8/01 8/15 9/01 9/30

2001 2002

2002

Hurricane

Gabrielle

-300

-200

-100

0

100

200

300

400

500

600

700

800

900

1,000

1,100

1,200

West

Highway

Creek

Trout Creek rout Creek

Mud

Creek

Taylor

River

Mouth

McCormick

Creek

MEAN MONTHLY DISCHARGE, Y DIS

C

H

A

R

G

E, MEAN MONTHL

IN CUBIC FEET PER SECOND

DATE

10/95

4/96

10/96

4/97

10/97

4/98

10/98

4/99

10/99

4/00

10/00

4/01

10/01

4/02

10/02

4/03

10/03

4/04

Figure 6. Mean monthly values of discharge in northeastern Florida Bay. Positive values indicate flow into 

Florida Bay.