U.S. Department of the Interior

U.S. Geological Survey

Introduction

The South Florida Ecosystem

Restoration Program is an intergovernmental effort to reestablish and

maintain the ecosystem of south

Florida. One element of the restoration effort is the development of a

firm scientific basis for resource decision making. The U.S. Geological

Survey (USGS) provides scientific

information as part of the South

Florida Ecosystem Restoration

Program. The USGS began its own

project, called the South Florida

Ecosystem Program, in fiscal year

1995 for the purpose of gathering

hydrologic, cartographic, and geologic data that relate to the mainland

of south Florida, Florida Bay, and the

Florida Keys and Reef ecosystems.

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 with canals,

levees, and pumping stations. These

structures have altered the hydrology

of the Everglades ecosystem on both

coastal and interior lands. Surfacewater flows in a direction south of

Lake Okeechobee have been regulated by an extensive canal network,

begun in the 1940’s, to provide for

drainage, flood control, saltwater

intrusion control, agricultural requirements, and various environmental

needs. Much of the development and

subsequent monitoring of canal and

river discharge south of Lake

Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has

been placed on providing a more

accurate water budget for internal

canal flows.

Importance of Flow and 

Water-Quality Information for 

Ecosystem Management

As part of the South Florida

Ecosystem Restoration Program, the

U.S. Army Corps of Engineers and

the South Florida Water Management

District (SFWMD) propose mod-ified

water deliveries to Indian Tribal

lands, Big Cypress National Preserve,

and other noncoastal areas of south

Florida. The proposed modified water

deliveries are designed to provide

flood protection and water-delivery

benefits to agricultural lands as well

as partial restoration of historic ecosystem conditions within both Seminole and Miccosukee Tribal lands

(fig. 1). The effects that these proposed modified water-delivery

changes will have on Indian Tribal

lands can only be determined if

internal flows and associated water

quality are accurately known. The

Everglades Construction Project,

which developed as a result of the

South Florida Ecosystem Restoration

Program, required diversion of the

C-139 Basin surface water to storm

treatment area 5 (fig. 1, STA-5) and

will cause a change in the volume and

quality of the water subject to Tribal

entitlement.

Project Goal

The objective of this project is to

evaluate approaches for quantifying

freshwater flows to and from Native

American lands and to provide

various hydrologic data to support

other Federal and State hydrologic

investigations. The implementation

and development of strategically

locating streamflow and water-quality

gaging sites will provide information

for determining future surface-water

flow requirements. Subsequent studies based on accurate flow calibrations generated by these sites will be

used for computation of nutrient loadings in the canal system. Providing

continuous-flow data at selected

impact points for internal basins will

complement the eastern flow canal

discharge network and allow for surface-water releases that are more

accurately timed. The accounting of

all significant hydrologic inflows and

ouflows to the Everglades ecosystem

of the south Florida mainland is a key

element of the South Florida Ecosystem Program.

Acoustic Techniques for 

Flow Measurement

Before the development of currently available acoustic instruments,

it was very difficult to gage flows in a

highly regulated network of canals

and streams. Standard methods for

field data collection and flow computations are impractical and inaccurate

because of the low velocities, flow

reversal, and the presence of submerged aquatic plants. With state-ofthe-art acoustic instrumentation, such

as the acoustic velocity meter (AVM)

and the Acoustic Doppler Current

Profiler (ADCP), it is possible to

more accurately gage flows in this

type of environment because of the

ability of AVM’s and ADCP’s to

quickly measure low or rapidly

changing water velocities. AVM systems have proven to be accurate

instruments in the measurement of

water velocities along a horizontal

path across a stream and can be permanently installed to collect continuous velocity data, which, along with

water-level data, are used to produce

continuous records of discharge.

ADCP instruments can be used

to measure water velocities in three

dimensions. These measurements can

then be used to calculate the total flow

through a stream section at a given

time. The ADCP uses the Doppler

shift from four acoustic beams transmitted downward (at set angles) to

measure the velocity of water, depth,

and distance traveled across the

stream transect. Field measurements

made with the ADCP’s can be used to

develop relations between continuous

recording gages collecting AVM

velocities and discharge at gaged

sites.

South Florida Ecosystem Program—Internal

Surface-Water Flows
SFWMD is planned to be initiated to

construct, calibrate, monitor, quality

assure, and produce daily water-level,

discharge, and nutrient loading tabulations. The SFWMD will provide

assistance by installing flow-weighted

samplers at USGS AVM gaging sites

for nutrient analysis (nitrogen and

phosphorus) in conjunction with

streamflow monitoring.

Data Collection

Two new continuous water-level,

AVM discharge, and water-quality

sites (fig. 1) will be added in conjunction with the larger plan to monitor

internal surface-water flows. Sites

will be located at critical water-delivery points for which information is

lacking on both the L-28 and L-28

interceptor canals (fig. 1). In addition

to the SFWMD’s existing network, a

joint effort between the USGS and

Figure 1. Study area showing location of Tribal lands, proposed 

data-collection sites, and major canals and levees.

SR 832

SR 832

SR 833

ALLIGATOR ALLEY

US 29

HENDRY CO

COLLIER CO

HENDRY CO

COLLIER CO

PALM BEACH CO

DADE CO

L-1

L-2

L-3

North Feeder

West

Canal

L-28

L-28

Tieback

C-139

Basin

L-4

Deer Fence Canal

Interceptor

SEMINOLE INDIAN

RESERVATION

MICCOSUKEE INDIAN

RESERVATION

PROPOSED DATA-COLLECTION

EXPLANATION

EASTERN

AGRICULTURAL

AREA

3A

S-140

STA-5

Proposed

STA-6

Proposed

HENDRY C0

SITES

STORM TREATMENT AREA

AND NUMBER

STA-5

L-28

Feeder Canal

WATER CONSERVATION AREA

LOCATION OF

STUDY AREA

0 10 MILES

0 10 KILOMETERS

Product Plans

Daily water-level, discharge,

and nutrient loading computations

will be made. Plans are to publish

all these data in the USGS report

“Water Resources for South Florida:

Volume 2A” on a yearly basis,

starting in the second year of the

4-1/2-year project (5/1/1996 to

9/30/2000).

Project Schedule

Tentative dates and the planned

project activities are summarized

below:

9/96: Automated remote site data 

stream command program language development by the 

USGS to facilitate SFWMD 

telemetry.

10/96: Construction and instrumentation of sites by the USGS with 

telemetry programming assistance from the SFWMD. The 

USGS begins calibration.

4/98: Daily value streamflow and 

stage computations and statistics completed for the 1997 

fiscal year and published in 

the USGS publication “Water 

Resources Data for South 

Florida: Volume 2A.” Nutrient loading computations to be 

made available in a yet to be 

determined format.

Fact Sheet 175-96

AUTHOR: M.H. Murray

For more information contact:

Mitchell H. Murray

U.S. Geological Survey

9100 N.W. 36th Street

Suite 107

Miami, FL 33178

(305) 526-2895 mmurray@usgs.gov