U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 010-99

August 1999

Florida

The U.S. Geological Survey (USGS)

is involved in water-related, geologic,

biological, land use, and mapping

studies that contribute to the safety,

health, and economic well-being of

Florida’s citizens. The USGS State

representative in the Tallahassee

office acts as the liaison for all

studies conducted by USGS scientists

in Florida. Water resources activities

are coordinated in Tallahassee,

Miami, Tampa, and Orlando. Scientists in these offices investigate

surface water, ground water and

water quality in Florida, working in

cooperation with tribes as well as

other Federal, State and local agencies and organizations.

The USGS Center for Coastal Geology and Regional Marine Studies was

established in St. Petersburg (see

location map on back) in 1988, in

cooperation with the University of

South Florida. The Center conducts

studies on mineral resources and on

coastal and regional marine problems,

including coastal erosion, climate

change, wetland deterioration, and

coastal pollution. A USGS mapping

office is located in St. Petersburg.

Also, the Earth Science Information

Center in Tallahassee provides USGS

information and directs inquiries to

the appropriate USGS or State agency

on earth science topics such as

cartography, geography, aerial

photography, and digital data. Biologists at the USGS Florida Caribbean

Science Center, located in Gainesville, conduct biological and ecosystem studies in Florida, Puerto Rico,

and the Virgin Islands.

South Florida Ecosystem Studies

Development of south Florida,

including more than 1,400 miles of

canals and 100 water-control structures, has contributed to a number of

environmental problems. These

problems include loss of soil, nutrient

enrichment, contamination by pesticides, mercury accumulation in the

biota, fragmentation of landscape,

loss of wetlands and wetland functions, widespread invasion by exotic

species, increasingly frequent algal

blooms in coastal waters, seagrass die

off, and declines in commercial and

recreational fisheries. Federal and

State agencies and environmental

groups have proposed that south

Florida and the Everglades be restored, to the extent possible, to

hydrologic patterns similar to those of

the predevelopment system. A

Federal Task Force, chaired by the

Department of the Interior (DOI), was

formed in 1993 to oversee restoration.

The USGS, the science agency of

DOI, carries out many of the scientific activities needed to support

restoration through the place-based

studies program, funding a diverse

group of projects in south Florida

(fig. 1). Research is well underway,

and in some cases is nearing completion. Major tasks of the program are:

• To study the history of the ecosystem to determine predevelopment

(last few hundred years) climatic

and environmental conditions in

south Florida.

• To monitor biologic, cartographic,

geologic, and hydrologic parameters over a long period of time

(fig. 2).

• To conduct regional and sitespecific multidisciplinary studies

to gather background information.

• To study the biological and chemical processes that affect and

control the cycling of nutrients,

sulfur, mercury, and other contaminants.

Figure 1. Study areas of the

Suwannee River Basin Studies, the

Georgia-Florida Coastal Plain NAWQA

Program, the South Florida NAWQA

Program, and the South Florida

Ecosystem Program.

Tampa

Miami

Orlando

Brunswick

Savannah

Jacksonville

Tallahassee

SOUTH

CAROLINA

GEORGIA

FLORIDA

G u l f o f

M e x i c o

A t l a n t i c O c e a n

Florida Bay

Florida Keys

Lake

Okeechobee

Everglades

0

0

50 MILES

50 KILOMETERS

GEORGIA–FLORIDA

 NAWQA

SUWANNEE RIVER

 BASIN STUDIES

EXPLANATION

SOUTH FLORIDA NAWQA

SOUTH FLORIDA 

 ECOSYSTEM PROGRAM
science for a changing world

• To develop and apply robust

models to sheetflow, ground-water

movement, evapotranspiration in

different vegetation communities,

and ecological interactions of key

animal species.

• To prepare topical synthesis

documents to analyze, summarize,

and integrate USGS results, and

describe the relevance of this

research to management issues.

The USGS web site describing

South Florida Ecosystem studies is

at “http://sflwww.

er.usgs.gov”.

The Suwannee River Basin—

Water Resources and Wetland

Habitats

The ground- and surface-water

resources of the lower Suwannee

River basin provide a variety of

important benefits to north-central

Florida. Although these resources

have not been highly developed,

demands are likely to increase from

users within the basin, from within

the Suwannee River Water Management District (SRWMD), and possibly from more populous areas of

Florida. The SRWMD entered into a

cooperative program with the USGS

to study factors affecting water

resources in the basin (fig.1). USGS

hydrologists are developing computer-based models to simulate the

karst-related, complex ground- and

surface-water interactions in the

basin. Environmental isotopes and

age dating techniques are being used

to determine the sources and chronology of nitrate contamination of

springs in the basin. Also, the relation

between sources of nitrate in spring

waters and changes in land-use

patterns over the past 50 years are

being studied. In cooperation with the

U.S. Fish and Wildlife Service, the

USGS is determining the effects that

altering a Suwannee River sill will

have on river flow and water-quality

regimes, and on ground water near

the sill.

A study to determine the relation

between wetland habitats and river

flow characteristics involves field

work to identify vegetation and soil

types in the floodplain, determine

land-surface altitudes, and monitor

hydrologic conditions. Analyses and

interpretations using map coverages

on a geographic information system

(GIS), calculations to determine

habitat areas, and analyses of longterm ground-water and surface-water

records are also being conducted.

Environmental Contaminants and

their Effects on Wildlife

More than 1,000 new chemicals are

released into the environment each

year, resulting in a growing potential

for health risks. Increasing evidence

suggests that exposure to some of

these chemicals, called endocrine

disrupters, can adversely affect the

immune, reproductive, and endocrine

systems of wildlife by interfering

with natural hormones. The USGS is

investigating the effects that these

chemicals may have on wildlife

species. Because waterways are the

ultimate recipients of agricultural and

industrial contaminants, aquatic

animals often serve as sentinels or

early indicators of environmental

stress. Field and laboratory studies

are underway to examine the effects

of herbicides, papermill effluent, and

sublethal doses of mercury on largemouth bass. Results of these studies

suggest that a variety of structurally

diverse pollutants can alter sex

steroid hormone levels, which could

lead to reproductive impairment and

population declines. USGS scientists

are exploring environmental factors

related to massive juvenile alligator

mortality in Lake Apopka, and the

effect of contaminants on various

mussel species in their early stages of

development. Findings suggest that

mussels in early stages of development, or offspring of exposed females, may be particularly sensitive

to the toxic effects of certain contaminants. USGS work will be expanded

to learn more about the mechanisms

of hormone actions and clarify the

direct and multigenerational effects of

contaminant exposure.

Florida Keys Coral Reefs

The USGS has conducted a series of

geophysical surveys on the marine

shelf, covering about one-half of the

Florida Keys National Marine Sanctuary. Information from the survey is

being used to map the geology of the

Keys, reef track, and shelf margin

during approximately the last 10,000

years. Florida Keys reef growth began

approximately 6,000 years ago, when

rising sea levels flooded the high-anddry south Florida platform. Florida’s

corals grow fast enough to have kept

pace with the known rate of sea-level

rise during the past 6,000 years;

however, less than 1 percent of the

reefs actually did keep pace, implying

periodic coral deaths. Carbon-14 agedating methods are being used to

determine the major periods of reef

demise and regrowth, which may lead

to finding a cause of the coral deaths.

The USGS, in conjunction with the

University of South Florida, will

study African dust to determine its

possible role in the periodic death of

corals and coral reef organisms. Coral

mortality became apparent in the

Figure 2. USGS hydrologists sampling

plants in the Everglades.
Florida

1970’s and is increasing at alarming

rates. This marked increase in coral

deaths appears to parallel the welldocumented rise in desertification in

Africa (beginning in the 1970’s) and

aerosol transport across the Atlantic

Ocean. African dust contains xenobiotics, such as spores and bacteria,

that have likely contributed to coral

reef mortalities throughout the

Caribbean basin.

Lake Studies

More than 7,800 lakes cover an area

of about 3,600 square miles, or about

6 percent of Florida. More than half

the lakes occur on the sandy ridges of

the central peninsula and are typically

of sinkhole origin. Because of the

mantle of permeable sands, groundwater flow systems predominate over

surface drainage (fig. 3), making the

central lakes district an important

area of recharge to the upper Floridan

aquifer system, the principal potable

water supply for the State. The

integral connection between lake and

ground-water hydrology in Florida

presents many challenges to lake

managers attempting to maintain

acceptable lake levels and prevent

water-quality deterioration from

residential and agricultural development.

Since 1995, USGS scientists, in

cooperation with the Southwest

Florida and St. Johns River Water

Management Districts and the Florida

Department of Environmental Protection (FDEP), have studied various

aspects of lake hydrology. Ground

water flows to lakes are being quantified using models. Ground-water

exchange with 10 lakes was estimated

using water budgets and geochemical

tracers. Another study used nitrogen

isotopes to identify sources of nitrate

in the shallow ground water around

lake basins. The USGS also is

evaluating the effects on groundwater exchange and lake-water

quality of augmenting lake levels in

the lake district north of Tampa Bay

with water from the Upper Floridan

aquifer. Regional, multi-lake studies

are underway to estimate groundwater inflow and historical lake-level

fluctuations. USGS geologists

recently used digital high-resolution

seismic systems to collect geophysical data from 30 lakes in north-central

Florida. Analysis of seismic profiles

for each lake showed that central

Florida lake development follows

four sequential stages to maturity.

Seismic profiles also were used to

locate possible breaches in the

confining layer that maintains water

levels in the lakes.

South Florida National WaterQuality Assessment (NAWQA)

Program

National Water Quality Assessment

(NAWQA) studies are being conducted in south-central Georgia and

north-central Florida, and in south

Florida areas, which cover about

19,500 square miles (fig. 1).

Studies indicate that fertilizer is a

major source of nitrogen and phosphorus in south Florida. Estimated

annual nitrogen loads are highest in

outflows from the Caloosahatchee

River basin and the major Palm

Beach canals, and lowest in outflows

from parts of the Big Cypress basin.

Annual phosphorus loads are highest

in the Peace River, and are also high

in the Caloosahatchee River and

major Palm Beach canals. Results of

the 3-year intensive sampling program show that nutrient concentrations vary widely both seasonally and

spatially in response to human and

natural influences. The most frequently detected pesticides in surface

waters are atrazine, metolachlor, and

simazine; chlorinated hydrocarbon

insecticides and PCB’s were detected

in fish and bottom sediments. DDT

compounds were detected in 25 of 27

fish samples in 1995, sometimes in

concentrations comparable to those

detected in fish in the early 1970‘s.

Ecological studies in south Florida

were completed to determine the

abundance and diversity of fish,

invertebrates, and algae. This is of

particular interest because of the

extensive alteration of predevelopment patterns of water movement and

storage. An assessment of groundwater quality in south Florida focused

on the potential influence of land uses

such as commercial, light residential,

and citrus and winter vegetable

farming.

Water Use and Supply in Florida

The population of Florida increased

by 7.4 million people (110 percent)

between 1970 and 1995. Data collected by the USGS, in cooperation

with the FDEP and water management districts, indicate that over this

same period of time, freshwater

withdrawals increased nearly 29

percent and saline water withdrawals

increased 13 percent. Between 1990–

95, however, Florida’s freshwater

withdrawals decreased by about 4

percent, due in part to conservation

and more efficient irrigation systems.

Orange County, in central Florida, is

an area of tremendous population

growth that has tripled ground-water

withdrawals since 1968. A study is

underway in Orange County to

determine the effects of ground-water

Figure 3. Generalized cross section

showing ground-water flow and

hydrogeology at a Florida ridge lake.

RECHARGE

SURFICIAL AQUIFER

SYSTEM

CONFINING

UNIT

UPPER FLORIDAN

AQUIFER

DIRECTION OF GROUND-WATER MOVEMENT

WATER

TABLE

RAINFALL
Printed on recycled paper

USGS office locations USGS State Representative

227 Bronough St.

Suite 3015

Tallahassee FL 32301

(850) 942-9500

FAX (850) 942-9521

USGS Home Page

http://www.usgs.gov

Reports and products

1-888-ASK-USGS

withdrawals on water levels and

wetland viability, of urbanization on

the natural regimes of streamflow,

and of land use on surface- and

ground-water quality.

Manatee Population Research

The endangered manatee is one of the

most unique and best known Florida

animals (fig. 4). Ongoing USGS

research is providing wildlife managers with the tools necessary for the

recovering populations of this marine

mammal. USGS biologists with the

Sirenia project are conducting longterm studies on the manatee’s life

history, population dynamics, and

ecological requirements, and have

pioneered several important tools,

including a computerized photoidentification catalog and a radio-tag

assembly for tracking manatees by

satellite. Scientists also are studying

manatee feeding habits and seagrass

ecology in high-use manatee areas;

the long-term, post-release success of

manatees rehabilitated in captivity;

manatee population genetics; and the

effects of eliminating industrial

warmwater discharges on manatee

habitats. Warm water discharges from

industrial sources help keep manatees

warm in cold weather. The results of

these studies will assist natural

resources managers in determining

factors important to manatee distribution patterns, fitness and ultimate

survival. USGS Sirenia Project

personnel are active members of the

Florida Manatee Recovery Team, an

interagency team under the direction

of the U.S. Fish and Wildlife Service,

which guides manatee research and

management activities.

Coastal Ecosystem Dynamics

Scientists from the USGS Florida

Cooperative Fish and Wildlife

Research Unit, in collaboration with Ochopee

Altamonte

Springs

Fort

Myers

Gainesville

Homestead

Jacksonville

Miami

Ocala

St. Petersburg

Tallahassee

Tampa

West

Palm

Beach

The USGS has 386

employees in Florida

the Archie Carr Center for Sea Turtle

Research at Eglin Air Force Base, the

U.S. Fish and Wildlife Service, and

several volunteer programs, are

evaluating the effects of coastal

dynamics and erosion on coastal

fauna. Some beaches in the Florida

Panhandle have erosion rates in

excess of 35 feet per year, due

especially to hurricanes. Vehicular

traffic, coastal construction, and

recreational boating further disturb

coastal habitats. Studies are underway

to improve understanding of the

nesting habits of threatened loggerhead sea turtles on northwest Florida

beaches, the inshore developmental

and foraging habitat of the endangered Kemp’s Ridley sea turtle, and

the effects of erosion on shorebird

nesting and foraging habitat.

Cooperative Mapping Programs in

Florida

For the past 8 years, the USGS and

the FDEP have cooperated to produce, maintain, and revise (as

needed) a digital base map for the

State. New image products have been

produced, and existing digital data

categories and 1:24,000-scale maps

have been revised. The collection of

color infrared aerial photographs was

initiated in September 1998 to

produce digital orthophoto quadrangles (computer-generated images

of aerial photographs having the

geometric qualities of maps). Also,

the USGS is updating 40 of Florida’s

most popular 1:24,000-scale topographic maps. Through the National

Cooperative Geologic Mapping

Program, the Florida Geological

Survey is funded to conduct geologic

mapping projects designed to aid in

resolution of ground-water protection, waste disposal siting, mineral

resource identification, and land-use

planning issues.

Figure 4. Manatee in Florida waters.