Hydrogeological units of Florida

STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Elton J. Gissendanner, Executive Director

DIVISION OF RESOURCE MANAGEMENT
Art Wilde, Dh/ctor
BUREAU OF GEOLOGY
Walter Schmidt, Chief

Published for the
FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE
1986

STATE OF FLORIDA
DEPARTMENT OF NATURAL RESOURCES
Elton J. Gissendanner, Executive Director

DIVISION OF RESOURCE MANAGEMENT
Art Wilde, Director

BUREAU OF GEOLOGY
Walter Schmidt, Chief

SPECIAL PUBLICATION NO. 28

HYDROGEOLOGICAL UNITS OF FLORIDA

Compiled by
Southeastern Geological Society
Ad Hoc Committee on
Florida Hydrostratigraphic
Unit Definition

Published for the
FLORIDA GEOLOGICAL SURVEY
TALLAHASSEE
1986

DEPARTMENT
OF
NATURAL RESOURCES

BOB GRAHAM
Governor

GEORGE FIRESTONE
Secretary of State

BILL GUNTER
Treasurer

RALPH D. TURLINGTON
Commissioner of Education

JIM SMITH
Attorney General

GERALD A. LEWIS
Comptroller

DOYLE CONNER
Commissioner of Agriculture

ELTON J. GISSENDANNER
Executive Director

LETTER OF TRANSMITTAL

Bureau of Geology
Tallahassee

August 1986

Governor Bob Graham, Chairman
Florida Department of Natural Resources
Tallahassee, Florida 32301

Dear Governor Graham:

The Bureau of Geology, Division of Resource Management, Department
of Natural Resources, is publishing as its Special Publication No. 28,
"Hydrogeologic Units of Florida."

This report was prepared by an Ad Hoc Committee on Florida
Hydrostratigraphic Unit Definition under the auspices of the Southeastern
Geological Society. As such, it addresses the issue of consistency of
nomenclature within the hydrogeologic community in Florida. This impor-
tant step should assist both governmental agencies and the private sec-
tor regarding the proper and consistent use of hydrogeologic terms
throughout the state.

Respectfully yours,

Walter Schmidt, Chief
Bureau of Geology

Printed for the
FLORIDA GEOLOGICAL SURVEY
Tallahassee
1986

CONTENTS

Page
Introduction ............. .......................... 1
Background ............... .......................... .2
Proposed description of Florida's regional hydrogeologic units...... 4
I. surficial aquifer system ...................... . . . 4
II. intermediate aquifer system or intermediate confining unit.. .5
Ill. Floridan aquifer system .................. ....... . 6
IV. Sub-Floridan confining unit . ................... ........ .7

TABLE

Guide to the relationship of regional hydrogeologic units to
major stratigraphic units of Florida ........... ........... 8

FLORIDA HYDROGEOLOGIC UNITS

compiled by

Southeastern Geological Society

Ad Hoc Committee on

Florida Hydrostratigraphic Unit Definition

INTRODUCTION

Historically, hydrogeologists have not agreed upon a method to classify
water-bearing rock units and sediments. In addition, units sucn as aquifers
and confining beds have not been formally recognized within the Code
of Stratigraphic Nomenclature. They are, however, informally acknowledg-
ed and may be named on a stratigraphic basis as beds, members, or for-
mations. This, along with the varying emphasis of different investigators
(reflected in interchanging of the terms hydrogeologic, hydrostratigraphic,
geohydrologic, etc.) has led to the inconsistent and poorly-defined set of
criteria currently applied to the mapping of hydrostratigraphic units.

BUREAU OF GEOLOGY

BACKGROUND

The geologic/hydrogeologic community in Florida has long recognized
the inconsistent use of various terms applied to entire aquifer units or por-
tions of them. Terms or phrases such as surficial aquifer, water-table
aquifer, sand aquifer, nonartesian aquifer, shallow aquifer, limestone
aquifer, Floridan aquifer, upper/lower Floridan, deep aquifer, secondary
artesian aquifer, intermediate aquifer, Hawthorn aquifer, principal aquifer
and many others have made the literature difficult to read and units dif-
ficult to correlate.
In May of 1982 the Second Symposium on Florida Hydrogeology was
convened in Gainesville, Florida. At that meeting an introductory panel
discussion was organized to discuss some of the problems relating to
hydrogeologic unit nomenclature and offer observations. Symposium at-
tendees, representing all factions of the Florida hydrogeologic communi-
ty, reached the consensus that clarification of the definitions and
nomenclature of Florida's hydrostratigraphic units was needed for effec-
tive communication. In conjunction with that symposium and with a shared
concern for this topic, the Southeastern Geological Society (SEGS) created
an Ad Hoc Committee on Florida Hydrostratigraphic Unit Definition. The
committee was established at that meeting May 12, 1982 by then SEGS
president, Ron Ceryak. The Committee's charge was to address problems
concerning the definition of hydrostratigraphic units in Florida and the
nomenclature applied to them.

SPECIAL PUBLICATION NO. 28

The Committee consisted of:
John Vecchioli, U.S. Geological Survey, Chairman
Richard Deuerling, Fla. Dept. of Environmental Regulation
David W. Fisk, Suwanee River Water Management District
James M. Frazee, Jr., St. Johns River Water Management District
Anthony E. Gilboy, Southwest Florida Water Management District
John J. Hickey, U.S. Geological Survey
Michael S. Knapp, South Florida Water Management District (now with
HydroDesigns, Inc.)
Thomas Kwader, (replaced by Jeffry R. Wagner) Northwest Florida Water
Management District
Fred W. Meyer, U.S. Geological Survey
Thomas M. Missimer, Missimer and Associates
Walter Schmidt, Florida Geological Survey
Daniel P. Spangler, University of Florida
C. Ross Sproul, CH2M Hill
Sam B. Upchurch, University of South Florida.

The Committee met as follows:
September 17, 1982, Gainesville
November 12, 1982, Orlando
January 28, 1983, Wakulla Springs
June 23, 1983, Tampa
October 7, 1983, Tallahassee
June 1, 1984, Tampa.

In addition, geographical subcommittee work sessions were held from
time to time under the direction of the Water Management District
members. The Committee expresses thanks to those hydrogeologists who
demonstrated interest in the work of the Committee by attending these
meetings and offering valuable comments.
The following proposed description of Florida's regional
hydrostratigraphic units reflects the consensus reached by the Commit-
tee in its deliberations. It is offered as a provisional working model to be
tested by the hydrogeologic community in their writings. A draft of this
text was submitted for review by the hydrogeological community through
the Southeastern Geological Society, the Florida Section of the American
Institute of Professional Geologists, the Miami Geological Society, and the
Florida Water Well Association.

BUREAU OF GEOLOGY

As an explanatory note, terms specifying lateral extent regional, sub-
regional, and local were intended by the Committee to have these mean-
ings in the context used herein: regional an extent approximating or
larger than the size of a Water Management District; sub-regional an
extent encompassing a few counties; local an area of less than a few
counties.

PROPOSED DESCRIPTION OF
FLORIDA'S REGIONAL HYDROGEOLOGIC UNITS

1. surficial aquifer system the permeable hydrogeologic unit con-
tiguous with land surface that is comprised principally of uncon-
solidated to poorly indurated plastic deposits. It also includes well-
indurated carbonate rocks, other than those of the Floridan aquifer
system where the Floridan is at or near land surface. Rocks mak-
ing up the surficial aquifer system belong to all or part of the upper
Miocene to Holocene Series. It contains the water table and water
within it is under mainly unconfined conditions; but beds of low
permeability may cause semi-confined or locally-confined conditions
to prevail in its deeper parts. The lower limit of the surficial aquifer
system coincides with the top of laterally extensive and vertically
persistent beds of much lower permeability.
Within the surficial aquifer system one or more aquifers may be
designated based on lateral or vertical variations in water-bearing
properties. In those parts of the State where all or part of the sur-
ficial aquifer system constitutes a major source of supply, aquifers
within it have been given distinctive names such as Biscayne aquifer
in southeast Florida and the "sand-and-gravel aquifer" in western
panhandle Florida. The term surficiall aquifer system" replaces
terms such as "water-table aquifer," "nonartesian aquifer,"
"shallow aquifer," "sand aquifer," etc., that have been heretofore
applied in the literature to this hydrogeologic unit.

SPECIAL PUBLICATION NO. 28

II. intermediate aquifer system or intermediate confining unit includes
all rocks that lie between and collectively retard the exchange of
water between the overlying surficial aquifer system and the
underlying Floridan aquifer system. These rocks in general con-
sist of fine grained plastic deposits interlayered with carbonate strata
belonging to all or parts of the Miocene and younger Series. In
places poorly-yielding to non-water-yielding strata mainly occur and
there the term "intermediate confining unit" applies. In other places,
one or more low to moderate-yielding aquifers may be interlayered
with relatively impermeable confining beds; there the term "in-
termediate aquifer system" applies. The aquifers within this system
contain water under confined conditions.
The top of the intermediate aquifer system or the intermediate
confining unit coincides with the base of the surficial aquifer system.
The base of the intermediate aquifer is at the top of the vertically
persistent permeable carbonate section that comprises the Floridan
aquifer system, or, in other words, that place in the section where
plastic layers of significant thickness are absent and permeable car-
bonate rocks are dominant. Where the upper layers of the persis-
tent carbonate section are of low permeability, they are part of either
the intermediate aquifer system or intermediate confining unit, as
applicable to the area. The term "intermediate aquifer system"
replaces previously used names such as "secondary artesian
aquifer(s)" and "shallow artesian aquifer(s)."

BUREAU OF GEOLOGY

ill. Floridan aquifer system thick carbonate sequence which includes
all or part of the Paleocene to early Miocene Series and functions
regionally as a water-yielding hydraulic unit. Where overlain by
either the intermediate aquifer system or the intermediate confin-
ing unit, the Floridan contains water under confined conditions.
Where overlain directly by the surficial aquifer system, the Floridan
may or may not contain water under confined conditions depen-
ding on the extent of low permeability material in the surficial aquifer
system. Where the carbonate rocks crop out, the Floridan general-
ly contains water under unconfined conditions near the top of the
aquifer system, but because of vertical variations in permeability,
deeper zones may contain water under confined conditions. The
Floridan aquifer system is present throughout the State and is the
deepest part of the active ground-water flow system on mainland
Florida.
The top of the aquifer system generally coincides with the
absence of significant thicknesses of clastics from the section and
with the top of the vertically persistent permeable carbonate sec-
tion. For the most part, the top of the aquifer system coincides with
the top of the Suwannee Limestone, where present, or the top of
the Ocala Group. In small areas of central peninsular Florida and
In southeast Florida where the Suwannee and Ocala are missing,
the Avon Park Limestone forms the top of the Floridan aquifer
system. In other parts of the State, permeable carbonate beds of
either the Hawthorn Formation, the Bruce Creek Limestone, the
St. Marks Formation, or the Tampa Formation constitute the up-
permost part of the aquifer system.
The base of the aquifer system in panhandle Florida is at the
gradational contact with fine-grained plastic rocks belonging to the
middle Eocene Series. In peninsular Florida, the base coincides
with the appearance of the regionally persistent sequence of
anhydrite beds that lies near the top of the Cedar Keys Limestone.
Within the Floridan aquifer system, one or more aquifers may
be designated based on vertical variations in water-bearing proper-
ties. The term "Floridan aquifer system" replaces the terms
"Floridan aquifer" and "principal artesian aquifer" that previously
have been applied to this unit.

SPECIAL PUBLICATION NO. 28 7

IV. Sub-Floridan confining unit strata of low permeability that limit
the depth of active ground-water circulation on mainland Florida.
In peninsular Florida the unit is comprised mainly of a sequence
of anhydrite beds interlayered with low permeability carbonate rocks
belonging to the Paleocene and older Series. In panhandle Florida,
the unit consists of fine-grained plastic deposits belonging to the
middle Eocene and older Series. The top of the unit is marked by
the sharp permeability contrast with the permeable carbonates of
the Floridan aquifer system. The base of the Sub-Floridan confin-
ing unit is poorly defined because of the inadequate data.

GUIDE TO THE RELATIONSHIP OF REGIONAL HYDROGEOLOGIC
UNITS TO MAJOR STRATIGRAPHIC UNITS* OF FLORIDA

PANHANDLE FLORIDA NORTH FLORIDA SOUTH FLORIDA
SYSTEM SERIES FORMATION D AI FORMATION YDROSTRATI FORMATION H A
YT ERFO GRAPHIC UNIT GRAPHIC UNIT GRAPHIC UNIT
QUATERNARY Holocene Terrace deposits
-----. Undifferentiated
terrace marine and Undifferentiated Miami Oslite suficial
fluvial deposits terrace marine and surficial Key Larg Liestone aquifer
uflumal deposit aquifer Key LargoLimrtone ifer
Pleistocene surial fl l dep s u Anastasia Formation system
aquifer Fort Thompson Formation

TERTIARY Citronelle Formation Mc k o Calahatchee Ma
Pliocene Miccosuket Formation ."*
icn Undiffer d Alachua Formation Tamniami Formation
Undifferentiated
S- intermediate intermediate
coarse plastics aquifer system aquifer system
Alum Bluff Group intermediate or or
Pensacola Clay confining unit intermediate inrmediate
Intracoasal Formaion confinin uni Hawthorn Formation cnr 1 Hawthorn Formation coining nit
onee HwhrFormato confining un confining unit
Miocen Hawlhom Formation -
Chipola Formation -
Bruce Creek Limestone Tampa Formation "
St. Mar tion S. ks Formation St. Mr orin
Chattahoochee Formation

Chickaiawhay Limestone Floridan
Oligocene Suiannee Limesrtne aquifer muwannee Limestone
Mlrianne Limestone sy Suwnee Limeone Floridan
Bucatunna Clay aquifer Floridan
system aquifer
Ocala Group system
Libon Formation -- -- Ocl roup Oala Group sy
Eocene Tallsaltt F*mation Avon Park Limestone Avon Park Limestone
Older Rocks Undiffer- Lake City Limestone Lake City Limestone
entiated sub-Floridan Oldsmar Limestone Oldsmar Limestone
confining
Paleocene Undifferentiated unit CeWar Keys limestone -oi-n Cedar Keys Limestone u oran
___________ saubb-lorkida
CRETACEOUS confining onfining
AND Udiffe ited Undiffertiated unit unit
OLDER -

* Terminology follows usage of Floride Bfurwu of Geology

SPECIAL PUBLICATION NO. 28

FLORIDA DEPARTMENT OF NATURAL RESOURCES

BUREAU OF GEOLOGY
FLORIDA GEOLOGICAL SURVEY
Walter Schmidt, Chief
Peter M. Dobbins, Admin. Asst. Alison Lewis, Librarian
Jessie Hawkins, Custodian Sandie Ray, Secretary

GEOLOGICAL INVESTIGATIONS SECTION

Thomas M. Scott, Senior Geologist/Administrator
Albert Applegate, Geologist Ted Kiper, Draftsman
Ken Campbell, Geologist Susan Kruhm, Staff Asst.
Cindy Collier, Secretary Ed Lane, Geologist
Shelton Graves, Research Asst. Jacqueline M. Lloyd, Geologist
Richard Howard, Laboratory Tech. Teresa Meyer, Staff Asst.
Richard Johnson, Geologist John Morrill, Core Driller
Jim Jones, Draftsman Albert Phillips, Asst. Driller
Frank Rupert, Geologist

MINERAL RESOURCE INVESTIGATIONS
AND
ENVIRONMENTAL GEOLOGY SECTION

J. William Yon, Senior Geologist/Administrator
Paulette Bond, Geologist Connie Garrett, Research Asst.
Laura Cummins, Research Asst. Ron Hoenstine, Geologist
Diane Donnally, Research Asst. Steve Spencer, Geologist

OIL AND GAS SECTION

L. David Curry, Administrator
Clarence Babcock, Engineer Joan Gruber, Secretary
Brenda Brackin, Secretary David Poe, Geologist
Robert Caughey, Geologist Joan Ragland, Geologist
Cynthia Cook, Geologist Gwendolyn Staten, Secretary
Charles Tootle, Engineer

DEPARTMENT OF NATURAL RESOURCES
BUREAU OF GEOLOGY

This public document was promulgated at a total cost
of $971.95 or a per copy cost of $0.78 for the purpose
of disseminating geologic data.

	Front Cover
	Title Page
	Letter of transmittal
	Table of Contents
	Introduction
	Background
	Proposed description of Florida's...
	Back Cover

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