U.S. Department of the Interior—U.S. Geological Survey

Background 

The embayments and estuaries of 

Florida’s southwest coast are an integral part of the south Florida ecosystem. Nutrients and other constituents 

are transported to these coastal waters 

by surface water and ground-water 

flow from the Everglades National 

Park (ENP) and the Big Cypress 

Preserve and by longshore and offshore tidal currents. The coastal area is 

an essential breeding ground for many 

estuarine and marine species and is a 

popular location for wilderness recreational pursuits as well as sport fishing. The volume of flow and the loads 

of nutrients being discharged from the 

streams draining the upland areas of 

ENP and Big Cypress Preserve 

currently are unknown. 

As part of Everglades restoration 

activities, the U.S. Army Corps of 

Engineers may change the volume or 

location of water deliveries to the 

ENP. Such changes could affect the 

volume or distribution of inflow and 

associated constituents that are transported into the coastal waters of 

southwest Florida. Proposals to 

change water deliveries to the Everglades National Park and efforts to 

improve the environmental health of 

Florida Bay cannot be evaluated without some understanding of the hydrologic and water-quality characteristics 

of tidal rivers and coastal embayments 

in the region. 

 The southwest coast of Florida is 

part of a wilderness area with unique 

hydraulic characteristics that has historically been described as the “River 

of Grass.” Flat terrain and lack of controlled topographic information has 

made it difficult to define drainage 

divides. Low gradients, coupled with 

tidal effects, create complex conditions 

under which to measure riverine flow. 

It has been almost thirty years since 

any effort has been made to monitor 

flow characteristics continuously in 

the area. Significant technological 

advancements have occurred during 

this time and this new technology can 

be applied to help obtain the information needed to make informed 

decisions about the future of this 

unique coastal area. 

Plan of Study

In 1996, the U.S. Geological 

Survey (USGS) through the South 

Florida Ecosystem Initiative began a 

4-year study of the flow and nutrient 

characteristics of two major streams 

that drain parts of the Everglades 

National Park. Efforts during the first 

3 years of the study will be devoted 

primarily to data collection and analysis. During the latter part of the third 

year and during the fourth year, 

Figure 1. Location of study area.

LOCATION OF

STUDY AREA

FLORIDA

G

U L F

O F

M E X I

C

O

Lostman’s River

Broad River

Harney River

Shark River

POTENTIAL SITES

EXPLANATION

0 5 MILES

0 5 KILOMETERS

emphasis will be on data analysis and 

completion of the final report.

 A reconnaissance of the southwest coastal rivers was conducted in 

June 1996 to identify the significant 

flows in the study area and to select 

two sites for discharge and water 

quality data collection. It is anticipated 

that the two sites will be near two sites 

studied by the USGS in the 1960’s. 

Potential site locations are shown in 

figure 1. Coordination with personnel 

from the ENP, the South Florida Water 

Management District, and the USGS 

will be established early in the study to 

identify additional hydrologic data 

collection needs. 

The two sites will be instrumented with an upward looking acoustic doppler current profiler (index 

water velocity sensor), a water-level 

sensor, and two specific conductance 

sensors. Data will be measured and 

recorded at 15-minute intervals.

Water Flows and Nutrient Loads to the 

Southwest Coast of Florida - A Study 
Fact Sheet FS- 179-96

Data will be collected during 

monthly site visits by USGS personnel. Stream discharge measurements 

will be made monthly at the instrumented sites using an acoustic doppler 

current profiler. Additionally, discharge measurements will be made at 

other sites during the monthly visits.

Monthly discharge measurements will be used to develop discharge ratings based on the in situ 

sensors and discharge measurements 

which will provide a continuous record 

of river discharge. The relation of 

upgradient water levels and coastal net 

water discharge will be evaluated. 

Existing ENP and USGS water-level 

sites will be used to collect the upgradient water-level data.

Water-quality samples will be 

collected monthly at the instrumented 

sites and periodically at two noninstrumented sites along the coast. 

Samples will be analyzed for total and 

dissolved nutrients and specific conductance. Additional water-quality 

samples will be collected during times 

of extreme hydrologic conditions.

Products

Data collected for this study will 

include discharge, concentrations of 

nitrogen and phosphorus, nutrient 

loads, water velocity, water level, 

water temperature, and specific conductance from a minimum of two sites. 

All data will be available from the 

USGS Tampa office on a provisional 

basis pending review and approval of 

the final report. After approval for the 

final report, all data will be considered 

finalized and will be unconditionally 

released to the public.

Flow, nutrient concentrations, 

and nutrient load data will provide 

part of the basic information needed 

to understand the hydrologic and 

water-quality characteristics for a part 

of Florida’s southwest coast. The 

analysis of these measurements will 

help characterize the current conditions for the two selected sites and 

explain the relation between upgradient water levels and southwest coastal 

stream flows, and the possible interaction between southwest coastal waters 

and the waters of Florida Bay. Flow 

and nutrient data can be used for 

descriptive purposes as well as serving as input to hydrodynamic and 

water-quality models that aid our 

understanding of the south Florida 

ecosystem. 

Collaboration and 

Partnerships

The South Florida Ecosystem 

Initiative provides a unique opportunity for the USGS and the many agencies conducting studies in the area to 

interact. Collaboration and partnerships with those agencies are anticipated for this study. 

This study will depend on a number of existing rainfall and water-level 

data collection stations that are maintained by other agencies. Collaboration with Everglades National Park, 

National Oceanic and Atmospheric 

Administration, and other USGS 

offices and divisions is anticipated to 

support continued data collection at 

these sites.

Results of this study will be useful to the Everglades National Park, 

National Oceanic and Atmospheric 

Administration, U.S. Corps of Engineers, U.S. Fish and Wildlife Service, 

U.S. Environmental Protection 

Agency, U.S. Geological Survey, 

Florida State Fish and Game Commission, South Florida Water Management District, universities, local 

agencies, and private interests who 

may use the data as primary or 

complementary information in their 

research, data collection activities, or 

computer model development.

Selected References

Fishman, M.J.,ed., 1993, Methods of 

analysis by the U.S. Geological 

Survey National Water Quality Laboratory--Determination of inorganic 

and organic constituents in water and 

fluvial sediments: U.S. Geological 

Survey Open-File Report 93-125, 

217 p.

Schomer, N.S. and Drew, R.D., 1982, An 

ecological characterization of the 

lower Everglades, Florida Bay, and 

the Florida Keys: U.S. Fish and 

Wildlife Service, Office of Biological Services, FWS OBS-82/58.1, 

246 p.

Simpson, M.R., and Oltmann, R.N., 1992, 

Discharge-measurement system 

using an acoustic doppler current 

profiler with applications to large 

rivers and estuaries: U.S. Geological Survey Open-File Report 91-487, 

27 p.

Stoker, Y.E., Levesque, V.A., and 

Woodham, W.M., 1996, The effect 

of discharge and water quality of the 

Alafia River, Hillsborough River, 

and the Tampa Bypass Canal on 

nutrient loading to Hillsborough 

Bay, Florida: U.S. Geological 

Survey Water-Resources Investigations Report 95-4107, 69 p.

Stoker, Y.E., Levesque, V.A., and Fritz, 

E.M., 1996, Discharge, water-quality 

characteristics, and nutrient loads 

from McKay Bay, Delaney Creek, 

and East Bay, Tampa, Florida, 1991-

93: U.S. Geological Survey WaterResources Investigations Report 95-

4167, 47 p.

by Victor A. Levesque

For more information, please contact:

Victor Levesque

U.S. Geological Survey

4710 Eisenhower Blvd., B-5

Tampa, Florida 33634

(813) 243-5800 extension 167

levesque@usgs.gov

July 1996