AMERICAN WATER RESOURCES
ground
drainage
for
water
There are several areas in the basin where ground
water now that originates outside of the Suwannee River basin
subbasins.
springs.
high.now conditions. In a study area adjacent to the Suwannee
River that consists predominantly of agricultural land use, 18 wells
tapping the Upper Floridan aquifer and 7 springs were sampled
three times during 1990 through 1994 for major diuolved inorpnic
constituents, trace elements, and nutrients. During a period of
above normal rainfall that resulted in high river stage and high
ground water levels in 1991,the combinationof increasedamounts
WATER
SURFACE
S.
Catchesl
unknown
and
manage
ecosystems.
watersheds.
toring
targeted
and
conduit
sinkholes,
as
{such
features
to protect
toward
water
surface water are hydraulically connected through
karst
John
designed
networks
Interactions
between ground water and surface
water typically result in a single dynamic flow system
numerous
from
effectively address comprehensive watershed management issues (Barnett et aI., 1995): (1) more coordinated management of ground water and surface water
resources; (2) more effective partnerships with local,
regional, State, and Federal government agencies; (3)
coordination of ground water and surface water monitoring efforts to assess the quality and quantity of the
water resources and delineate the boundaries of
three-dimensional watersheds; and (4) the development and maintenance of comprehensive statewide
data bases for water resource information and moni-
INTRODUCTION
Ground
recharge
FDEPhas identified several key objectives to
The
<KEY TERMS: geochemistry; water quality; ground water hydrology; ground water/surface water interaction I; hydrologic tracers; ilOtopes; watershed management.)
in Florida.
areas,
Suwan-
the
to
water
ground
by
discharged
was
nitrate
Jell
rewlt,
gram
nee River.
watersheds
some
a
As
aquifer.
the
in
reactions
denitrification
by
nitrate
of diaaolved organic carbon and decreased I_Is of diuolved oxygen
in ground water created conditions favorable for the natural reducof
In
drainage pathways to areas of discharge may contribute to chemical and biological contamination of
water supplies. Such contamination in karst areas
has been documented in many studies (White, 1993).
Legislation enacted in 1993 mandated that the
Florida Department of Environmental
Protection
(FDEP) develop and implement measures to protect
the functions of ecosystems in the State. Watershed
management is one of the main components of a pro-
CJ'OIBeI
surface water buin boundaries during both low-now and
oriented
boundaries
surface
that
with
indicate
coincide
DOt
do
patterns
now
typically
water
buinl
water
ground
(below background
levels) and enriched amounts of oxygen-18 and
deuterium
in ground water indicate mixing with wrface water in
parts of the buin.
ComparilOn
of surface water and regional
tion
and
systems in the underlying limestone, and springs)
that facHitate the exchange of water between the surface and subsurface, particularly where the Upper
Floridan aquifer is unconfined (Figure 1). Unique
problems can arise in protecting both ground water
and surface water quality in karst areas because of
the direct and rapid transport of recharge through
conduits to the subsurface and through resurgence by
betweenthe surfaceand subwrface. Low radon-222concentrations
in many
1997
FLORIDAl
WATER
BASIN,
J.
Joshua
ABSTRACT: Ground water and surface water constitute a lingle
dynamic I)'ltem in most parta of the Suwannee River basin due to
the presence of karst features that facilitate the interaction
DECEMBER
AND
RIVER
GROUND
DeHan,
S.
SUWANNEE
Rodney
THE
Katz,
G.
Brian
IN
INTERACTIONS
BETWEEN
ASSOCIATION
Hirten,
NO.6
38.
VOL.
JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION
IPaper No. 97010of the Journal 0( 1MAmerican WolerResources
Association(formerly WolerResolUUBBulletin). Dl8cuaaloD8are open
WATER
AMeRICAN
THE
a
JOURNAl
RESOURCESAssocIATION
230,
Research
Suite
Senior
St.,
32301;
Robinson
E.
Florida
GOIS
Inc.,
Tanahaaee,
3015,
Engineering,
Suite
Law
St.,
32304;
Bronough
Florida
of Florida, Department of Geology, 1112 Thrllngton Hall, Gainesville, Florida
1237
JAWRA
Orlando, Florida 32801; and Research Assistant, University
32611.
N.
227
Tallahauee,
Survey,
St.,
GeoJogicai
Tenneuee
U.S.
W.
903
Survey,
Hydrologist,
Geological
Florida
Scientist,
Reeearch
1. 1118.
2Respectively,
until Au
Ground Water and Surface Water in the Suwannee
sub-
River
Rain-
character-
The
winters.
mild
and
is
subbasin.
and
River
subtropical
summers
is
Fe
Santa
the
subbasin,
River
basin
the
warm
long,
Suwannee
thereare largevariationsbetweenlocationsand from
the
of
February
some
late
from
produces
season
rainy
typically
April
late
through
but
divided into five subbasins (Figure 2) based on
surface drainage patterns: the Suwannee River basin
shorter
year to year. Approximately
50 percent of the average
annual rainfall occurs from June through September,
sub-
be
can
basin
The
1996).
Hatzell,
and
(Ham
lower
abundance
an
and
streams,
tributary
of
number
small
the
fall averages 132 em per year (Crane, 1986); however,
of Upper Floridan aquifer springs. Land uses in the
basin are predominantly forest, agriculture, and wetland
in
a
by
topography,
and
climate
and lowland
basin,
ized
wetland
Alapaha
the
The Suwannee River basin in Florida consists of an
area of 11,000km2 (Figure 2). The basin is characterized by karstic
River Basin, Florida
above the Withlacoochee
River (Upper Suwannee
River subbasin), the Withlacoochee
River subbasin,
the
Y
STUD
Between
AREA
Interactions
831t'
~'!"O,
~\cd
-'"
.
GROUND-WATERLEVELS
0
BACKGROUNDGROUND-WATER
.
BOTH GROUND-WATERLEVELS
QUALITY
RIver
STATION-On
WATER
Suwannee
~~~
I
the
SAMPUNG
KILOMETERS
040
20
0
I
I
,20
ij
.
""
'
I'
0
AND
QUALITY
.
".
29°
Figure 2. Study Area, Suwannee River Basin in Florida, Location of Monitoring Sites for Ground
1239
JAWRA
AsSOCIATION
RESOURCES
WATER
AMERICAN
THE
Of
JOURNAl
Water Levels and BackgroundGroundWater Quality, and SurfaceWater Subbasins.
Ground Water and Surface Water in the Suwannee
and dolostone) of the Upper Floridan
Improvement
Water
Surface
are
levels
water
ground
which
conrecorders)
and
basin,
wells
43
the
in
water-level
at
sites
back-
monitor
to
designed
ions, nutrients,
avoid
to
trace elements,
for
years
Water
three
contamination.
every
water
sampled
is
wells
these
of ground
selected
were
watershed
River
Suwannee
areas
major
and selected
part
as
Also
1992).
ai.,
et
(Maddox
compounds
organic
water
quality
are being
studied
on
practices
land-use
of
effects
the
FGWQMNP,
the
of
ground
at a mixed
urban-industrial
site and at an agricultural study
area in the Suwannee River basin.
As part of the National Water Quality Assessment
six
from
Georgia-Florida
water
the
of
sampled
has
study
USGS
the
(NAWQA)
Plain,
Program
Coastal
the
along
increase
on
impact
aquifer
system
(Crandall
and
Berndt,
1996).
Sevensites on the SuwanneeRiver in Florida and one
by
biologi-
sampled
and
are being
quality,
Fe River
material,
bed
for
NAWQA
site on the Santa
water
an
wells in its regional background network for the surficial
loading.
nitrogen
adverse
by
development
an
accompanied
have
increased
to
can
due
wells
107
The
ground water quality of the principal aquifers in the
and
(Ham
River
Suwannee
upper
Increasing
corridor
fields
Program
wastewa-
from
discharges
by
affected
the
in
1996).
River
tank
quality
water
Network
its
and
river
the
where
2),
(Figure
River
are
P)
as
Hatzell,
Monitoring
baseline or background water quality of the major
aquifer systems within Florida and to determine the
effects of various land use activities on ground water
from
(Ham
P
as
mgiL
0.5
than
less
generally
were
trations
lacoochee
tributaries
mgiL
1
ter treatment plants, livestock feedlots, paper mills,
and phosphate mines (Hand et al., 1990). Naturally
occurring phosphate deposits result in relatively high
background phosphorus concentrations (greater than
Suwannee
328
(using
Quality
(FGWQMNP), which was established to delineate the
known
and Hatzell, 1996), except in reaches of the upper
Suwannee River, above the confluence with the With-
septic
the
Currently,
at
measurements
monthly
Water
concen-
phosphorus
total
Median
N.
as
mgiL
0.4
measurements
includes
tinuous
River
Suwannee
the
of
concentrations
Nutrient
1990).
and its tributaries for the period 1970 to 1991 were
low, with median nitrate concentrationsgenerally less
Since 1987, information on ground water quality
has been collected as part of the Florida Ground
quality.
and
(Hull
river,
river
the
the
in
of
flow
quality
annual
water
the
average
the
of
influence
percent
strongly
at 32 wells.
et al., 1981;Crane, 1986).The contribution of ground
water sourcesto the water quality of the Suwannee
River is discussedin greater detail in a later section.
Water-quality conditions in most sections of the
SuwanneeRiver are generally very good(Hand et al.,
in
of
SRWMD
lished
being
1977).
al.,
et
(Rosenau
basin
the
of
and Management (SWIM) program, which was estab-
Together, these springs contribute about 100 ma/s to
the Suwannee River, which represents about 30 to 50
than
part
con-
the
of
South
river.
the
of
part
this
along
part
lower
the
fluence with the Santa Fe River, the basin is largely
internally drained. Approximately nine first magnitude (average discharge of 2.8 ma/s or more) and 63
second magnitude (average discharge of 0.28 to 2.8
ma/s) springs discharge into the Suwannee River in
lished to evaluate present surface water and ground
water conditions and to determine short and longterm trends and conditions. As part of a surface water
network, lake water levels are being measured regularly at 17 sites, river stage and discharge are monitored at 18 sites, and daily rainfall is recorded at 34
sites. Surface water quality samples are col1ected
monthly, bimonthly, or quarterly at 52 sites by the
as
the
of
the
2),
Hamilton,
portion
(Figure
of
this
for
flow
intersection
Counties
the
the
Suwannee
near
provides
and
contrast,
lakes
In
and
river.
Columbia,
common
river channel deepens and the river is incised into
carbonate rocks. Limestone outcrops and shoals are
river
River Basin, Florida
level, and water-quality monitoring networks in the
Suwannee River basin. These networks were estab-
aquifer. Surface runoff draining swamps, flatwoods,
1989.
(limestone
in
Between
measured
Interactions
water
ASSOCIATION
1996).
analyses of water from
1241
of
parts
confined
poorly
the
107
the Upper Floridan aquifer (Figure 2) include data
JAWRA
rainfall,
U.S.
and
FDEP
the
with
maintains
RESOURCES
(USGS),
WATER
AMERICAN
Survey
THE
OF
cooperation
in
(SRWMD)
JOURNAL
Geological
Hatzell,
METHODS
Maddox et al., 1992). Chemical
wells
water and ground water networks.
River Water
Management
District
Methods of collection and analysis of ground water
samples, along with data screening procedures and
quality assurance information for ground water quality data have been previously described (Katz, 1992;
tapping
of
part
as
collected
been
have
leveD
water
ground
areas. During the past 30 years, a considerable
amount of hydrologic data (such as river stage and
extensive
surface
The Suwannee
AND
APPROACH
localized
of
studies
of
number
small
a
of
exception
Historically,
ground water and surface water systems in the Suwannee River basin have been monitored separately under specific programs, with the
and
(Ham
species
cal
Monitoring Programs in the SuwanneeRiver Basin
~
Interactions
Between
Ground
Water and Surface Water in the Suwannee
River Basin, Florida
TABLE 2. Mean Concentration,Number of Samples,and Rangeof Concentrations(in parentheses)of Selected
Water-Quality
Constituents
Determined
at Four SucceBBive Downstream
Locations
(see Figure
2) on the Suwannee
River.
::
1981).]
ol.,
et
(Hull
otRiver
Mouth
1968-1977
From
209
73; (29447)
234
74; (48.500)
51
7.; (21-76)
41
74; (6.3-81)
74; (2.3-37)
6.4
74; (0.4-23)
30
74; (0.4-150)
83
74; (3.9.150)
93
74; (14-160)
1.7
66; (0.1-10.8)
12
66; (2.4-44)
28
66; (3.4-54)
33
66; (5.9-57)
0.96
66; (0.1-4.4)
3.2
66; (1.0-13)
6.7
66;(1.1~1)
5.2
66; (1.2-9.6)
3.6
66; (0.1.0.1)
66; (2.9-12)
0.3
66; (2.6-9.9)
IM};(3.3~11)
0.65
66; (0.2-1.7)
0.73
66; (0.1-3.5)
1.1
66; (0.5-3.0)
1.3
66;(0.5-10)
7.6
66; (0.4-12)
7.6
66; (1.2-12)
7.1
66; (3.0-11)
7.5
66; (1.3.13)
6.2
66;(1-17)
18
66; (1.0-43)
14
66; (1.0-32)
15
66; (1.0.27)
0.05
74; (0.01-0.22)
74; (0.01-0.72)
0.57
74; (0.05.1.1)
0.54
74; (0.05-1.0)
0.678
16; (0.37-0.94)
0.73
46; (0.11-1.6)
83; «0.02-1.4)
0.35
44; (0.01-0.93)
0.057
74; (0.004-0.19)
0.75
74; (0.05-8.9)
0.12
74; (0.04-0.33)
0.10
73; (0.05-0.27)
points
NO3
in
representing
the
Hi
Suwannee
2) probably
is the
spring
water
elevated
with
River
result
NOa
the
in
of
water
.
spring
and
waters
in
the
by
water
shown
river
these
increase
(Table
WATER
RESOURCES
AsSOCIATION 1243
11; «3-350)
is
the
of
Florida,
chemistry
Branford,
near
water
32; «3-570)
A substantial
an
near
and
the
170
210
0.«
12; (110-660)
TOC
in
river
4.9
Figure
3.
concentration
near
of the
Branford,
of
Fla.,
contribution
concentrations.
of
This
JAWRA
,
74; (2.0-36)
closeness
0.15
this change in
decrease
the
16
6.0
HCOsions resulting a
of
chemistry
substantial
from
122
74; (42-355)
water
and
Ca
by
a
AMERICAN
THE
OF
are
68
74: (43-160)
Branford, Florida, is controlled largely by spring
water discharge to the river, and the similarity in
JOURNAl
which
7.31
73; (6.28-8.16)
type. Accompanying
The
is
pH.
in
type
water
Kilometer.
7.15
74; (1i.56-8.15)
460
Fe,
5.88
74; (3.85-7.92)
near Branford, Florida, where the water
dominated
is
increase
water
Ca-HCOs
Wilcox
55.5
4.20
5; (280-630)
particularly
Branford
123
74; (3.06-7.43)
~
PO4-orthoas P
~
Sprinp
242
410
pH
.
in
Suwann-
Benton
316
Constituent
Fe,
dissolved
~>.
Diatance
and
and
TON
of
Name
Station
exception
the
with
constituents
chemical
of
[Concentrationsare expressedas milligrams per liter unlessotherwise noted.SC denotesspecificconductance;
~cm denotesmicrosiemensper centimeter;Alk denotesalkalinity, expressedas CaCOa;TOC denotestotal
organic carbon;TON denotestotal organic nitrogen as nitrogen 00; P denotesphosphoM1s;
~gIL denotesmicrograms
per liter. Data are summarizedfrom 1989-1995(Hornsbyand Mattson, 1996)and representtotal concentrations
Interactions
Between
Water and Surface Water in the Suwannee River Basin, Florida
Ground
(A)
35
!J~ ">,.>a! "e.
W
..J
..J
~
30
.,
j
M
M
J
N
S
J
JMM
N
S
J
M
JM
N
ALAPAHA FIRE TOWER WELL
'(8)
I
c.
.
~
1989
1990
1992
1991
1993
1994
Figure 4.(a) Relation of Alapaha River Stage and Water Level in Alapaba Fire Tower Well, 1989-1994, and
(b) Variation in pHand Specific Conductance in Water from Alapaha Fire Tower Well, 1989-1994.
1245
high-flow
from
February
dur-
constituents
these
of
concentrations
conditions
through
April
JAWRA
ing
Low
1996).
seaand
pH,
AsSOCIATION
specific conductance of river water have been
observedat severa] locations (Hornsby and Mattson,
Suwan-
the
in
stage
1996). Large
concentrations,
RESOURCES
WATER
AMERICAN
THE
NOs
and Mattson,
in
(Hornsby
fluctuations
OF
JouRNAL
sonal
nee River
and
concentrations
NOs
between
connection is supported by the inverse relation
River Basin, Florida
com-
Comparison of Ground Water and Surface Water
Basin Boundaries
world
the
of
when
Water and Surface Water in the Suwannee
anomalous
Ground
systems
river
are
Between
that
other
of
concentrations
those
U
to
pared
and
Interactions
basins
com-
of
drainage
because
karst
of
challenge
delineation
consists
which
recharge,
autogenic
1991
January
to
1990
flow
water
ground
of
Patterns
1984.
flow
of
low
maps
constructed
aquifer
Floridan
potentiometric-surface
for
May
to
Upper
the
lines
that
flow
assumed
that
and
was
It
isotropic
was
conditions.
flow
regionally
high
on
These
lines.
superimposed
were
equipotential
to
patterns
flow
perpendicular
water
very
were
flow
water
ground
of
patterns
The
nected.
AssocIATION
and
high-flow
conditions;
surface
map con-
There are several areas in the basin where ground
water that originates outside of the Suwannee River
basin crosses surface water basin boundaries during
however,
ground
conditions;
to
compared
m
6
For example,
conditions
conditions,
low-flow
high.flow
and
nearly
by
increased
during
low-
measured
both
levels
and high flow conditions.
County,
during
high-flow
levels
both low flow
in Hamilton
water
high
1247
exists
in
eastern
Hamilton
surface
potentiometric
a
where
water flow lines cross surface water drainage boundparticularly
water
low-flow
only the potentiometric
and
western
JAWRA
RESOURCES
WATER
AMERICAN
THE
OF
during
more
days
with
in the Upper Floridan aquifer are probably restricted
to smaller, localized areas compared to those areas
where ground water levels are affected by high river
stage. Dilution effects may account for the localized
impact of river water on aquifer water quality.
JOURNAl
from
during
during
mixing
conditions
structed for high flow conditions is shown (Figure 5).
aries,
water
high-flow
concert
in
25-45
approximately
of
river
with
the
from
(Hirten,
river
fluctuated
also
river
the
from
lag
a
time
from
low-flow
basin and the Santa Fe River subbasin(Figure 5)
therefore,
tancesof much less than 3 km (Hirten, 1996).Impacts
quality
with
boundaries indicate that ground water basins do not
coincide with surface water drainage subbasins,
except in some parts of the lower Suwannee River
similar
(1996) noted that
between a rise in river stage and a rise in ground
water levels. Geochemical data for ground water near
the river are very limited, but do indicate the possibility that river water mixes with ground water over dison water
period
where ground water and surface water are well con-
located
the
wells
in
from
km
3
measured
than
less
levels
located
Water
km
3
was
Hirten
dry
December
during
conditions
April
the
and
aquifer
were
of ele-
high-flow
outward
during
area
extend
this
can
in
km
aquifer
3
least
at
Floridan
to
Upper
river
wells
1996).
than
there
stage; however,
period
determined
ground
during
effect
conditions based on a high correlation (r2 = 0.90)
between river stage and water levels measured in
river
and
surface water basin boundaries (delineated based on
topography)
for the major subbasins
within
the
Suwannee River basin. Generally, the comparison of
ground water flow patterns with surface water basin
vated river stage on the potentiometric surface of the
with
limestone
Bran-
to
The
a relatively
a wet
were
Floridan
river
the
from
and
away
1996).
into fractured
was
Upper
Ellaville
from
reach
75-km
a
along
conditions
(Hirten,
surface
the
between
connections
hydraulic
the
of
study
A
aquifer
low-flow
conditions
systems,
that
and
ford, revealed that the direction of the hydraulic gradient in the aquifer is toward the river during
high-flow
infiltration
ic conditions:
of water
aquifer
Floridan
Upper
the
of
parts
deeper
trend
This
direction.
downstream
a
in
increased
from
contribution
River and the unconfined
in karst
River basin were comparedfor two different hydrolog-
supply spring water to the lower reaches of the river
(Burnett et ai., 1990).
Suwannee
considerable
contribution
of diffuse
concentrations (0.155 to 0.917 dpmIL) and the concentration of 226Ra in these springs progressively
to the increasing
that
internal runoff into sinkholes (White et al., 1995).
Two-dimensional (areal) boundaries for surface
water and ground water subbasins in the Suwannee
226Ra
high
relatively
have
springs
magnitude
order
of 226Ra (0.189 disintegrations per minute per liter,
dpmIL) compared to the mean concentration for stations south of Branford (0.270 dpmIL). Even though
226Ra has a strong affinity for adsorption on aquifer
minerals, the concentration of 226Ra in ground water
is generally several times to several orders of magnitude higher than in surface waters. Several first-
attributed
shown
from
from
north of
concentration
mean
lower
a
stations
have
water basins typically do not coincide with corresponding ground water basins (Gunay, 1988). Sinking
streams can reappear in different basins because
ground water divides are controlled by aquifer properties as well as by topographic conditions. Carbonate
outcrop areas and joint and fracture patterns must be
accurately mapped in great detail to determine the
using
River
traced
was
Suwannee
the
Branford
to
to
tended
have
et ai., 1990). Stream
(Burnett
Branford
of
water
of
south
input
Studies
springs
large
The
concentrations).
226Ra
a
plex patterns of surface water and ground water flow.
U
high
and
UAR
low
(generally
seeps
and
springs
represents
The
tration) with large amounts of ground water flow from
accurate
concen-
U
low
UAR,
(high
runoff
surface
some
of
ing
(Crane, 1986).The anomalousvalues result from mix-
Ground Water and Surface Water in the Suwannee
centrations
by
generated
wastes
from
in the
Upper
Floridan
aquifer
(Andrews,
1994; Ceryak and Hornsby, 1996). Water of the Upper
River
in this
area
and the discharges
Mattson,
and
(Hornsby
river
the
in
NOs
centration
of
to
quality
water
on
effect
its
and
as part of the FGWQMNP.
The study
6)
(Figure
County
in a 73-km2 study area adjacent
Lafayette
River
to
are being evaluated
in
flow
Ground
more than one spring, Wilson and Skiles (1988) concluded that there is an extensive network of threedimensional braided conduits in the aquifer system
and unique ground water drainage divides do not
exist within a few hundred meters of the spring discharge points.
water
1996).
tracing experiments. Basedon the dispersion of dye to
area consists
mainly of agricultural land use, such as dairy and
poultry farms, cropland, and silvaculture. In April-
.
1249
JAWRA
AsSOCIATION
RESOURCES
WATER
AMERICAN
THE
Figure 6. Lafayette County Agricultural Study Area With Potentiometric Surface
of Upper Floridan Aquifer and Location of Sampling Sites.
OF
from
many springs and seepsin the riverbed affect the con-
the Santa Fe River was studied using rhodamine dye
JOURNAl
the
to
discharges
and
toward
flows
Floridan
Suwannee
among
Park
aquifer
explo-
human
Springs
interconnection
of
Ginnie
from
degree
the
discharge
basin,
that
River
Fe
loading
High
conditions
flow
SuwanneeCounties has resulted in elevatedNOs con-
ration (cave diving). In one such study in the Santa
springs
Natural Remediation of Nitrate in Ground Water
poultry and dairy farms, and fertilizers applied to
cropland along the Suwannee River in Lafayette and
dyes, naturally
cases,
some
in
involving
and,
isotopes
techniques
different
for
determined
be
need
to
tracer
occurring
using
River Basin, Florida
nitrogen
separate shallow and deepground water flow systems
based on the depth or open interval of a well.
To define ground water and surface water drainage
areas more accurately on a local scale, the hydraulic
connections between discharge areas (such as springs)
for the Upper Floridan aquifer and for surface water
Suwannee
Between
the
Interactions
~
EXPLA
,"
"~I.
DIll
...
0I8id8
NurNMlrofolillMlolll
(17)
the
.
t
(
8011
'
'",
Median
,
7511
peanIIIt
.
.
.';
c"
ili~/
"
,r
!
~
~
W
I-
"0
w
c,>'>
,
a:
"
/.
'
!
c~;::;
f)
~
.
2!81
$
1OfI
17)
(
,
1011
IIId8OIh
~
.
"',"
",-,
.'
.
,", .
"' in'
:
T_.".
5)
""'!
" "-'
-'.'
:
22
c.IL"';?
~'j.:1;
",
'
NATION
"
24
Water and Surface Water in the Suwannee River Basin. Florida
Ground
~'N'Y"'
(A)
Between
~.
Interactions
March
1991
April-May
June
1994
(B)
1990
;,
'1 'l
"I~ ,,'
,~
f""!J~"'r3
'h" ,;i:'< ","
,.I!'IO;L,'
,: ,r"".,
,.
J;.
w
~
a..
i:
«...::::
~
'
10
-_J
.
i-,
;
r'-
~.~,
-"
',i,
,',
'0'
If:'"
>~f..rti;;'U(1
Ma~h
1991
1990
';J
June
1994
in (A)Ground
WaterLevels
and(B)Nitrate-NConcentrations
in Ground
Water,
Differences
7.
,
;"'~
April-May
Figure
,'iIi'
,Co
'o',;:tf,
.'
C)
,I;.;;i<~'
[1',/;";:;
.
,',
",d",
-""ll'L
I
"f>-,,""!,
. I..(}
1"':'1',
"
'
",;
2
"':
,)
"
!.!
.
n
)"'~"")
,
"q!
6
l '
"
'fjq!;~
~
8
4
.J
-"~,
,\;,,'1 "H;:,l.i"
flt'j
(17)
q,c;;Jt;,:,J
."
zS2
,.J ,.
.':.
'
a:<C
I--a:
, -"
...~..." ,"'",
.
'
'/"
(~"l'j').
-.:::
w
,:.: '
10th peIC8I1tIe
j:;:J,J,I"J;iT
'I
,'I'
.
e,>.
9001 percentile
75th
percenble
"'Median
251h"Jjercentile"
en
.
'
:.
.101h and 90th percentiles
.
a:
:i::i
f";
Number of observations
.
I-
16
.
(26)
18
(fJ
$
:\ ,'.'-
*
20
w
a::
!he
22"
outside
~
values
',
Data
24
AssocIATION
1251
JAWRA
RESOURCES
WATER
AMERICAN
1'1£
JOURNAL
OF
Lafayette County Study Area, During April-May 1990, March 1991, and June 1994.
Interactions Between Ground Water and Surface Water in the Suwannee River Basin, Florida
conditions except in very localized areas. Sampling of
ground water and surface water needs to be coordinated and conductedduring changing hydrologic conditions, especially during periods of high and low flow.
Existing information
on ground water levels col-
solution
with
differ-
One
states.
other
their
benefit
Water
Spring
and
Water
Nitrate
Geologi-
U.S.
1990-93.
Florida,
North
in
the
in
Radium
10:237-255.
1990.
Dcetae,
S.
Biogeochemistry
Cowart,
and
J.
B.
Estuary.
Suwannee
River
Basin,
Florida.
Report.
WR-97-02,
Quality
Report
District
Groundwater
1996.
Management
Water
Hornsby,
D.
River
and
R.
Ceryak,
Suwannee
ofUrani.
Environ-
23:651-
the
Quality
in
Distribution
The
Environmental
Radionuclides
1994,
C.
Journal
Review.
Decay-Series
W.
and
B.
J.
Thorium
A
-
and
Cowart,
um
ment
662.
Quality of Surficial
Water
Crandall, C. A. and M. P. Berndt, 1996.
Aquifers in the Georgia-Florida Coastal Plain. U.S. Geological
Survey Water-Resources Investigations Report 95-4269, 28 pp.
Crane, J. J., 1986. An Investigation of the Geology, Hydrogeology,
are
and Hydrocbemistry
ofthe
Lower
Suwannee
River Basin. Flori-
Determine
Groundwater
Gains
and
Losses
to
Davi-
A.
SFe
C.
Streamflow
and
Jobnson,
222Rn
A.
N.
Using
1991.
R.
Kincaid,
Wanninkbof,
R.
H.
T.
R.
K.,
K.
and
Ellins,
da GeologicalSurvey Report ofInvestigations No. 96, 205 pp.
son,
future
foreseeable
the
RESOURCES
in
WATER
available
be
AMERICAN
THE
will
Of
funding
Upper
81pp.
deposition).
AsSOCIATION
of the
Council of State Governments,
1995. Ecosystem
Connections:
Results of the Council of State Governments
Ecosystem Protections Questionnaire.
Lexington, Kentucky, 30 pp.
It is unlikely that adequate State and Federal
JOURNAl
Resources
in the
Santa Fe River. Hydrogeology of the Western Santa Fe River
to
1253
JAWRA
and
atmospheric
Florida
Florida Bureau of Geology Report of Investigation, No. 87, 165
pp.
Hillen,
where
program
an
monitoring
an ecosystem
evaluated both spatially and temporally (such as soil,
ground water, surface water, sediments, the geologic
framework,
Water
to confirmand doc-
comprise
River
Burnett,
Suwannee
for
paths
flow
along
water
ground
of
sampling
ized
establish
to
integrated
that
Strategy.
Ceryak, R, M. S. Knapp, and T. Burnson, 1983.Tbe Geologyand
ument the importance of naturally occurring denitrification reactions in parts of the watershed
The results of this study add to our understanding
of hydrochemical interactions between ground water
and surface water across spatial and temporal scales.
The study findings also improve our knowledge of the
importance of natural and anthropogenic factors on
observed changes in environmental conditions that
are related to the linkage of ground water and surface
water systems in a watershed. In order to protect,
sustain or manage watershed ecosystems, it is critical
resources
Implementation
I and II, 36 pp.
con-
nitrogen isotopes and nitrous oxide compoundswould
various
Farms
Management
Department of Environmental Protection,September1995,Vola.
sistent with the denitrification process.More specialprovide much needed information
1994.
J.,
Ecosystem
C.,
were
Dairy
Barnett, E., J. Lewis, J. Marx, and D. Trimble (Editors), 1995.
W.
water
Four
Near
cal Survey Water-Resources Investigations Report 94-4162, 63
pp.
of
concentrations
the
and
in
Increases
pH
in ground
W.
Andrews,
during
system
flow
water
ground
sluggish
more
a
of
dan
aquifer.
bicarbonate
Ground
period
A
tributaries).
its
and
river
the
in
of
LITERATURE CITED
this period along with increased amounts of dissolved
organic carbon (from river water) and less dissolved
oxygen in ground water created conditions favorable
for the natural reduction of nitrate in the Upper Floriand
will
manuscript: J. B. McConnell, D. M. Schiffer, and three anonymous
reviewers.
above normal rainfall in 1991 resulted in high river
stage and high ground water levels. The combination
calcium,
and
recognized for their constructive comments that led to an improved
naturally during periods of high flow conditions (high
water levels in the Upper Floridan aquifer and high
stages
Florida
data and hydrologic information. The following reviewers are also
and
for programs
ent monitoring objectives.
Reduction in nitrate concentrations in ground
water by denitrification processesis likely to occur
of
agencies
coalitions
The authors acknowledge the joint funding for this study by the
Intergovernmental Task Force on Monitoring Water Quality and
the Florida Department of Environmental Protection. The authors
also thank Ron Ceryak and David Hornsby, Suwannee River Water
Management District, for their generous sharing of water-quality
A.
by different
of
ACKNOWLEDGMENTS
compromisedsomewhat becausethese data were collected
watershed
ments.
aquifer
and to obtain more detailed flow patterns. The use of
ground water level data to evaluate the coincidence of
ground water and surface water basin boundaries was
in
Floridan
be the establishment
the
of
map
the
refine
for the Upper
might
Burnett,
surface
to
needed
be
would
wells
tional
water subbasin divides. To define areal and vertical
ground water basin boundaries more precisely, addipotentiometric
problem
communities by not only identifying the threats to the
health and function of watersheds, but also by being a
part of the solution to existing problems.
surface
across
water
ground
of
flow
is
there
that
potentiometric-surface maps) generally do not coincide with boundaries for surface water subbasinsand
The
from
(delineated
to this
watershed coalitions, involving the private sector
stakeholders,that could be responsiblefor generating
the necessaryresourcesfor proper watershed assess-
lected during low- and high-flow conditions indicates
that ground water basin boundaries
throughout
watersheds
conduct delineation and mapping of zonesof interaction between ground water and surface water in
in
the
Suwannee
River
Water
Zone:
Saturated
the
in
28(6):657.1668.
Denitrification
Research
Natural
Resources
1992.
Hydrology
Studies.
Program:
Background
and
Quality
Upchurch,
B.
S.
Ground.Water
Scott,
M.
Florida's
T.
1992.
Network
Hydrogeochemistry.
Florida Geological Survey Special Publication, No. 34, 364 pp.
Puri, H. S. and R. O. Vernon, 1964. Summary of the Geologyof
Rosenau,J. C., G. L. Faulkner, C. W. Hendry, Jr., and R. W. Hull,
Management
1977. Springs of Florida. Florida Department of Natural
Resources, Bureau of Geology Bulletin No. 31, 461 pp.
District,
Scott, T. M., 1988.The Lithostratigraphy of the Hawthorn Group
Florida. U.S. Geological Survey Water-Resources Investigations
Report 96-4176, 14 pp.
Western
<Miocene) of Florida. Florida Geological Survey Bulletin No. 59,
148 pp.
Taurus Region, Southwestern Turkey. In: Estimation of Natural
Scott, T. M. 1991.The Geologyof the Santa Fe River Basin, Cen.
Gunay, G., 1988. Natural Rechargeof Kant Aquifers in
GroundwaterRecharge,L Simmen (Editor). D. Reidel Publishing Company, Dordrecht,
Holland,
tral.Northem Peninsular Florida. In: Hydrogeology of the Western Santa Fe River Basin. Southeastern Geological Society Field
Trip Guidebook No. 32, pp. 1-12.
pp. 405-422.
Ham, L. K. and H. H. Hatzell, 1996.Analysis of Nutrients in the
United Nations Economic Commi8lion for Europe, 1993.Manual
Surface Waten of the Georgia-Florida Coastal Plain Study Unit,
1970-91. U.S. Geological Survey Water-Resources Investigations
Report 96-4037, 67 pp.
for Integrated
Monitoring
Network.
Suwannee
River
the
of
of Florida,
Water
1977.
U.S.
Proceedings of the Second Conference on Environmental
Problems in Karst Terranes and Their Solutions,
Nashville,
Tennesaee, Association of Ground Water Scientists and Engineers,
1968
Surface
of
August
Geological
Survey
Water
Ecosystem
Management
Task
121-141.
Statis-
to
Approach
pp.
pp.
Modem
497
A
York,
1983,
New
Conover,
York,
J.
New
W.
and
Wiley,
L.
John
R.
tics.
Iman,
ResourcesInvestigation Report 80.no, 97 pp.
Interagency
Cooperative
ProPollution
Effects,
Wilson, W. L. and W. C. Skiles, 1988. Aquifer Characterization by
Quantitative Dye Tracing at Ginnie Spring, Northern Florida.
Manage-
Quality
Florida,
1981.
Mann,
B
Basin,
W.
River
and
Dysart,
Suwannee
E.
J.
the
W.,
in
R.
Hull,
Water
December
Force,
1995.
The
Ecosys-
tem Approach:Healthy Ecosystemsand SustainableEconomics,
Vol. I-III. Washington,D.C.
Intergovernmental Task Force on Monitoring
Water Quality, 1995.
Strategy for Improving Water-Quality Monitoring in the United
States. Final Report and Technical Appendices, Febroaty 1995,
117 pp.
Katz, B. G., 1992,Hydrochemistry ofthe Upper Floridan Aquifer in
Florida. U.S. Geological Survey Water Resources Investigations
Report 91-4196, 37 pp.
Katz, B. G., T. M. Lee, L. N. Plummer, and E. Busenberg, 1995a.
Evolution
of Groundwater
Florida:
1. Flow Patterns,
Near
a Sinkhole
Lake,
Age of Groundwater, and
F.
B.
Groundwa.
Revesz,
of
M.
K.
Evolution
Busenberg,
Leakage. Water Resources Research
E.
1995b.
Lee,
Plummer,
N.
M.
L.
T.
G.,
and
B.
Jones,
Katz,
Influence of Lakewater
31(6):1549-1564.
Chemical
Chemical
Northern
U.N.
White, W. B., D. C. Culver, J. S. Herman, T. C. Kane, andJ. E. Myl.
roie, 1995.Karst Lands.American Scientist 83:450-459.
ment District Annual Report WR-96-O2, 130 pp.
through
1993-1996.
Environment, Helsinki.
White, W. B., 1993. Analysis of Karst Aquifers. In: Regional
Ground-Water Quality, W. A. Alley (Editor). Van Nostrand Reinhold, New York, New York, pp. 471-489.
Hornsby,D. and R. MattlOn, 1996.SurfaceWater Quality and Biological
Phase
Environmental Data Centre, National Board of Waters and the
Near
System
Dynamics
Aquifer
Hydraulic
and
Floridan
Upper
the
and
1996.
River
J.,
J.
Hirten,
Suwannee
Geochemical
Thesis, University
Programme
Transboundary
Air Pollution,
International
gramme on Integrated
Monitoring
on Air
Quality Assessment for the State of Florida Technical Appendix.
Department
of Environmental
Protection,
Tallahassee, Florida,
321 pp.
Branford, Florida. Masten
Gainesville, Florida, 101 pp.
Monitoring,
Economic Commission for Europe Convention on Long Range
Hand, J., V. Tauxe, M. Friedemann, and L. Smith, 1990. Water
ter Near a Sinkhole Lake, Northern Florida: 2. Chemical Patterns, Mass-Transfer
Modeling,
and Rates of Chemical
Reactions. Water Resources Research 31(6):1565-1584.
Kincaid, T. R., 1994.Groundwater and SurfaceWater Interaction in
the Western Santa Fe River Basin Near High SpringR, Florida.
Masters Thesis, University of Florida, Gainesville, Florida, 186
WATER
AMERICAN
THE
OF
1254
JoURNAL
pp.
JAWRA
In: 180-
Press.
Lloyd,
M.
J.
(Editors).
L.,
G.
Elsevier
Copeland
Maddox,
R.
Monitoring
(Editon).
Brierly
in Catchment
Florida and a Guidebook to the Classic Exposures. Florida Geo.
logical Survey Special Publ. IS,312 pp.
356-369.
L.
nell (Editors).
Giese,G. L. and M. A. Franklin, 1996,Magnitude and Frequencyof
Floods
F.,
Series Radionuclides
tope Tracersin CatchmentHydrology,C. Kendall and J. McDon-
In: Planetary
pp.
C.
York,
and
Aquifen.
New
Brierly,
A.
York,
J.
New
Daldwell,
E.
Reinhold,
D.
Nostrand
Ecology,
Van
in British
Water
Kraemer, T. F. (in press).Applications of Uranium- and Thorium.
Monitoring Network of the SuwanneeRiver Water Management
District. Florida Department of Environmental Protection Quality AssuranceProject Plan 94-0266,102 pp.
Firestone, M. K., 1982. Biological Denitrification. In: Nitrogen in
Agricultural Soils, F. J. Stevenson(Editor). American Societyof
Agronomy,MadilOn, WilCOnsin,pp. 289-326.
Foster, S. S., D. P. Kelly, and R. James, 1985. The Evidence for
Zones of Biodenitrification
Review.
A
Korom,
Basin, Field Trip Guidebook No. 32, Southeastern Geological
Society, pp. 41-62.
Environmental Services and Permitting, Ine. 1995. Water-Quality
Monitoring and Biological Studies of the Surface Water Quality
S.
Katz, DeHan,Hirten, and Catches
RESOURCES
AsSOCIATION
Katz, DeHan,Hirten, and Catches
a..
fEen
OJ:
w~
z-
t-z
DC!)
u.t-
a:
~w
wZ
:JQ
en
WATER
pH
LEVEL
HCO3
Ca
Cf
DOC
Eh
denitrification.
by
water
ground
in
NOa
reduction
per-
water to the Suwannee River during high-flow periods than would be discharged during low-flow periods.
redox
71
concentra-
in
from
NOs
As a result, lessNOawouldbe dischargedby ground
decrease
a
Water
which
in
1991.
showed
to
wells
the
also
1990
of
sampled
from
percent
75
decreased
wells
of
cent
tions
from
sponding decrease from 1990 to 1991. For instance,
chloride concentrations
increased in water samples
of
and other reduced speciesthat could serve as edonors,createdconditionsfavorablefor the natural
corre-
a
show
not
did
ions
major
other
and
chloride
Figure 8. Changesin Water Level,Eh, pH, and Concentrationof SelectedConstituents in
GroundWater From 1990to 1991in Lafayette County Study Area.
potential based on measured Eh, and an increase in
measuredpH, Ca2+,HCOs-, and DOC (Figure 8).
The increase in pH, Ca2+,and HCOs- is consistent
of
con-
the
to
Andrews
JAWRA
ground
water
water flow and
aquifer
during
of high
the
in
water
with
periods
ASSOCIATION
1252
Floridan
RESOURCES
extent
Upper
water
ground
significantly
WATER
the
river
1991,
sluggish
a
that
March
reduced amounts of dissolved oxygen in the aquifer,
combined with increased amounts of organic carbon
of
shallow
than
concentrations
likely
in
between
ground
mixing patterns can be revealed only through consistent monitoring with time and during varying hydrologic conditions. Insufficient chemical and hydrologic
information exists at present to determine the lateral
AMERICAN
system
is
it
flow
interactions
water.
Complex
THE
water
hydrochemical
and surface
water.
reiterate,
To
ground
oxygen
dissolved
lower
occur in deeper rather than in very shallow ground
water because deeper ground water had considerably
mixing
likely
more
Counties,
was
and Lafayette
denitrification
that
noted
in Suwannee
(1994)
farms
species), artificially introduced tracers (dyes and
other synthetic compounds such as sulfur hexafluoride), and detailed data on ground water levels and
river stage provide important information on the
OF
of
that sulfide is
also an e-donorfor the denitrification. In a study of
the fate of NOs in ground water beneath severaldairy
of
percent
percent
the possibility
CONCLUSIONS
The direct linkage between ground water and surface water in parts of the Suwannee River basin has
been demonstrated by analysis of hydrologic and
water-chemistry
data collected during regional
assessments and localized studies. Naturally occurring tracers (isotopes, major and minor chemical
JOURNAl
wells sampled indicates
SUMMARY
AND
concentra-
NOs
61
from
sulfate
60
in
decreased
water
in
increase
with
iron
approximately
from
an
water
dissolved
water
Also,
yielded
in
that
wells
in
tions
centrations.
the
increase
with the overall denitrification
reaction presented
earlier. Additional evidence for more reducing conditions in ground water in 1991 compared to 1990 is the
flow
Katz, DeHan, Hirten,
May 1990, March
1991, and June 1994, water
and Catches
sam-
and seven springs
that discharge
+ 5CH20 + 5CaCOa + 4H+
4NOa-
ples from 18 wells tapping the Upper Floridan aquifer
+ 10HCOa
into the Suwannee
> 2N2
+ 5Ca2+ + 2H20
-
overall
in
an
of calcite
or
pro-
Floridan
are
Upper
ions
the
and
shown
resulting
dissolution
comprising
Other
not
denitrification
consumed,
that
bicarbonate
matrix
reaction.
duced
are
Assuming
nitrogen
are
and manganese
dis-
in
increase
an
include
would
conditions
anoxic
iron
concentrations.
reactions
denitrification
that
confirm
positively
To
measure
to
desirable
be
would
it
as
pro-
were
network
isotopes
monitoring
nitrogen
for
nitro-
such
of
analyses
composition
constituents,
However,
paths.
and
the
of
gases
part
as
nitrogen
included
isotopic
indicator
flow
the
specific
along
and
in
oxides
species
gen
dissolved
not
above normal rainfall, compared to water levels in
1990 and 1994 (near normal rainfall).
Nitrate concentrations in ground water varied
widely for sampling periods in 1990, 1991, and 1994
nitrous
changes
of
months
three
following
wells
some
occurred
water levels in 1991 increased by as
at
m
6
as
much
this
but
Floridan
Upper
solved
have
aquifer. Ground
ions
pH.
limestone
In
Interme-
-) and
reduced
in
produced
repre-
donor.
(NO2
of
hydrogen
(in
are
reaction.
increase
nitrite
calcium
above
substrate
as an electron
as
N20)
reaction,
for water to flow
the
into
River
Suwannee
the
the potential
and
organic
lev-
water
than
lower
were
River
Suwannee
the
near
from
els in the river creating
serves
occurs,
the
toward
northeast
to
Suwannee River (Figure 6). However, during the 1991
sampling period, heads in the Upper Floridan aquifer
the
an
such
the
1994).
north
is
direction
flow
(NO
in
In the study area, the dominant regional ground
water
gases
col-
samples
water
in
NOa
of
1993 (Andrews,
by CH20
products,
by
in May
expression,
diate
aquifer)
lected
ratios
isotope (15N/14N)
above
sented
attributed to a combination of leachate from livestock
wastes and septic tanks, based on measured nitrogen-
the
indicators
dis-
In
was
water
in
River
NOa
of
Suwannee
source
the
to
principal
springs
The
by
charged
stituents.
River were analyzed for NOa and other chemical con-
from the Upper Floridan aquifer (in mg/L as nitrogen)
data
deni-
for
potential
the
study,
changes
in the
comparing
by
(below)
evaluated
and
concentration
of
County
study
area
in
sampled
during
and
Lafayette
1990
the
The following
in
levels
the
in
existed
conditions
that
that
ground
1991
March
Measured
during
aquifer
denitrification.
Floridan
promote
Upper
would
for
wells;
sampled
all
in
levels
water
by as much
as
rainfall
normal
above
of
months
three
following
m
6.4
from
decreased
gradient
hydraulic
The
1991.
in
Floridan
Floridan
aquifer.
aquifer
near
Also,
the river
a
the
damming
from
a
from
discharging
resulted
water
system
on
flow
river
the
by
sluggish
Upper
in the Upper
heads
were lower
than
water
levels in the river, probably resulting in the development of a "saddle" in the potentiometric
surface
the river
could
flow
into
these hydrologic
parts
of
changes
in
of NOa measampled
concentrations
of
lower
71
substantially
from
were
from
Accompanying
wells
water
the aquifer.
percent
whereby
in
acceptors, (2) the presence of heterotrophic or
autotrophic bacteria, (3) e-donors,such as organic carbon, or other reduced species such as Fe2+and sulfide, and (4) an anaerobic environment or one with
restricted O2availability.
The overall reaction involving denitrification in a
carbonateaquifer can be representedby the following
expression:
effect
more
(e-)
electron
terminal
as
oxides
N
other
increased
0.0019 in 1990 to 0.0012 in 1991. It is likely that
sured
1992).
(Korom,
aquifers
in
NOa
of
amounts
and
levels
bacteria
by
NO3
of
transformation
the
involves
lower
ly
water
from
results
probably
1991
in
sampled
water
ground
tion
The process of denitrifica-
For denitrification to occur in an aquifer, four conditions are required (Firestone, 1982): (1) the presence
NOa
some
in
concentrations
NOa
in
decrease
large
instance,
(present in the soil and aquifer material) to nitrogen
gases, such as N20 and N2' This process serves as a
major sink for nitrogen and can result in substantial-
of
informa-
sam-
water
ground
with
compared
high)
were
levels
The
ples collected in 1990 and 1994.
reactions.
and geochemical
76
from
water
in
measured
were
NOa
of
centrations
percent of wells sampled in 1991 (when ground water
denitrification
hydrologic
conevidence
lower
increased
Substantially
water
aquifer.
water
in
fluctuations
Floridan
provides
Upper
tion
the
with
associated
were
1991.
concentrations
NOa
of
distribution
the
in
0.20 « 0.05-9.5); and June 1994,2.0 « 0.02-22.). The
variation
is
reactions
hydrologic
1991,
water
March
ground
0.02-17);
for
1.52 «
species
1990,
chemical
April-May
selected
were:
this
for
Therefore,
trification
samples
water
in
concentrations
NOa
of
parentheses)
gram.
(Figure 7). For instance, the median and range (in
1991 compared to 1990. River water with high
concentrations (Table 2) could provide organic carbon
needed for denitrification;
however, organic carbon
derived from the limestone may serve as another edonor source (Foster et ai., 1985). Furthermore, the
TOC
lower
NOs concentrations
likely
were
due to denitrifi-
ASSOCIATION
RESOURCES
WATER
AMERICAN
THE
OF
1250
JoURNAL
JAWRA
cation rather than dilution because concentrations of
Katz, DeHan, Hirten, and Catches
Figure 5. Potentiometric Surface of the Upper Floridan Aquifer and Ground Water Flow
Patterns During High Flow Conditions Relative to Surface Water Subbasins.
therefore,
wens
in
the
present
sys-
flow
water
ground
regional
the
network
to
made
was
ASSOCIATION
RESOURCES
attempt
No
WATER
1248
basin.
(approximately 250 wens in the basin) are not ideany
suited to define two-dimensional
boundaries for
ground water basins accurately in most areas of
AMERICAN
was
that
program
a
of
part
as
collected
were
maps
JAWRA
tems;
and
a
River
from
small area in northeast Taylor County to a much larger area that includes central Madison County (Figure
5). Ground water basin boundaries do not coincide
with surface water basin boundaries in Madison, Taylor, and Jefferson Counties.
It is important to note that the ground water level
data used for constructing potentiometric
surface
designedto delineate the regional potentiometric surface of the Upper Floridan aquifer rather than to
delineate ground water basins. The wens in this network are open to different depths in the aquifer and
the open intervals of these wens probably intercept
THE
conditions
con-
Of
high-flow
27-m
localized
during
by the
Suwannee
(represented
JOURNAl
enlarges
high
the
tour)
surface
both
Columbia County (Figure 5}. Also, the area of a potentiometric
Katz, DeHan, Hirten, and Catches
water
as
pH
of
Floridan
ground
trace
to
used
Ra,
U,
of
or
syspress).
of
orders
concentra-
in
water
separation
three
to
its
Kraemer,
surface
their
geochemical
mobility
the
different
hence,
two
and,
be
gas
a
can
is
1994;
and
to
by
on
rely
leading
water
ground
Burnett,
water
surface
in
concentration
the
than
higher
Fe
Santa
measure-
the
of
River),
reach
Suwannee
2-km
a
the
to
a
that
in
tracer
a
loss)
revealed
radon
as
hexafluoride,
for
injected
water
correct
was
(sulfur
SF6
surface
in
and
that
and
gas
and
even
that
was
finding
noteworthy
Fe
Santa
actually
is
the
that
streamflow
shows
stream,
aquifer
many
in
aquifer
Floridan
Upper
the
at
visible
are
that
Siphons
river.
55
as
much
As
subsurface.
the
to
was
area
study
this
at
discharge
and
water
ground
in
concentrations
overlying
is
where
and
minerals
material
aquifer
unconfined
where
of
is
places
dissolution
aquifer
in
as
intense
such
by
breached
been
has
aquifer
Floridan
Upper
and
had
(0.57)
springs
ratios
Many
activity
J,LgiL).
low
(1.76
very
had
concentrations
springs),
the
U
high
of
of
much
interactions
occurring
are
the
water
where
naturally
surface
and
aquifer
and
example,
For
water
river
are associated with areas where the
Floridan
and
Upper
recent
occurring,
the
and
number
a
in
used
been
have
compounds
the
ground
estimate
typically
sinkholes. For example, three water samples from a
Suwannee
River tributary
basin (including
the
springs near Branford, Florida, and wells upgradient
various
water
for
river
of
aquifer
Floridan
proportions
mixing
Upper
the
the
from
previous studies to establish and quantify the linkage
complex.
spring
(U)
teristics
more
quantify
to
used
be
can
1995b),
1995a,
al.,
et
precisely
water
organic
the
to
the
diverted
of
high U concentrations(0.5 to 10 J,LgiL).
These charac-
(222Rn,
radon,
including
isotopes
environmental
uranium
surface water were used to determine the source and
amount of recharge for different parts of the aquifer
and ground water contributions
to the Suwannee
River (Crane, 1986). Most sampled sites produced
waters with low activity
ratios (less than 1.0) and
water,
river
range
Upper
the
for
and
straightforward
as
values
the
from
overlaps
pH
conductance
not
is
in
1981)
range
al.,
water
in
et
the
specific
well
Tower
(Hull
measured
7.2
because
between
Alapaha
relation
to
values
4.7
levels
the
the
and
from
rela-
Differences in the 234U/238Uactivity ratio (UAR)
flow conditions. Environmental isotopesand synthetic
between
gaining
Floridan
lost
along
being
is
of
that
water
of
the
mixing
might
and
of
one
1981)
pH
the
However,
indicator
1992),
al.,
et
al.,
useful
and
water.
a
levels
surface
be
et
(Hull
5.6
(Maddox
water,
would
water
and
pH
between
water
that
7.1
river
percent
medi-
the
in
differences
on
Based
a
is
Upper
River
being
0.007)
=
water
(a
and
pH
significant
between
0.41)
a
was
places
statisti-
not
is
relation
the
however,
There
aquifer.
the
222Rn
of
synthetic
to
water
particularly
One
with
conduc-
specific
and
levels
water
between
found;
was
significant.
in
of
pH
aquifer,
an
the
expect
ground
of
tion
supplied by resurgent surface water that originated in
the the overlying Santa Fe River, and not water from
the Upper Floridan aquifer (Kincaid, 1994).
Ellins et al., 1991; Kincaid, 1994); and oxygen
(18()/16(), hydrogen (D/H), and carbon (13C/12C)(Katz
between
map of the
surface also provide direct evidence that stream water
aquifer in this area, 5.3 to 9.4 (Katz, 1992).
Hydrologic tracers, such as naturally occurring
more
along
study
tributary
a
(a
used
responding increases in ground. water discharge to
springs, loss of streamflow to ground water, and input
to springs from resurgent streamflow (Kincaid, 1994).
conduc-
1981),
al.,
specific
et
Hull
median
J,l8/cm,
higher
(39
a
having
conductance
water
specific
aquifer
correlation
tance
cally
levels
=
controlled
studies
is
and
222Rn
ground
in
example,
(Cowart
in
processes
which
These
physical
Rn,
water.
and
and
fractionation
tems
For
tion
magnitude
water.
In
River
and
ground
increasesin river dischargewere accompaniedby cor-
though the regional potentiometric-surface
tance (310 JJ,S/cm,Maddox et al., 1992). A negative
(r
losses to ground
median
lower
having
water
river
of
mixing
the
to
due
conditions, surface water enters the aquifer, and the
conductance of water in the aquifer decreases. This is
volatile
ments
flow
high
During
4).
(Figure
well
the
from
samples
represents a mixture of river water and ground water.
The relative proportions of ground water and surface
water in the mixture can be evaluated qualitatively
based on changes in specific conductance of water
correlation
were
to rivers and streamflow
which
well,
Tower
Fire
Alapaha
the
from
sampled
increasing stage in the Alapaha River during 1989-94.
Further evidence for the connection between
ground water and surface water is indicated by water
positive
222Rn,
and
water influx
(238U and 234U), radi-
with
0.001)
=
(a
significantly
increased
well
age between ground water and surface water is evidenced by the correlation of ground water and surface
water levels. For example, variations in the stage of
the Alapaha River are highly correlated (r = 0.87)
with water levels in the Upper Floridan aquifer (Figure 4). Ground water levels in nearby Alapaha Fire
Tower
such as uranium
(226Ra),
um
radionuclides,
link-
hydraulic
the
basin,
the
in
locations
some
In
in 1994 and again in 1995 is due to dilution from a
large contribution of surface runoff generated during
spring rainfall.
activity
ratios
greater
than 0.75, which Crane
attributed to a mixture of ground water from areas of
high recharge with ground water from areas of little
JAWRA
AssociATION
RESOURCES
WATER
AMERICAN
THE
Of
1246
JOURNAl
or no recharge.The SuwanneeRiver has UAR values
Katz, DeHan,HirteD, and Catches
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WATER
AMERICAN
THE
OF
JOURNAl
1244
JAWRA
41now J811IJ WOJj
Wf18Jlsdn 8:JUf1IS!O
ResouRCES AssocIATION
and Catches
and the Upper Floridan aquifer, point sources, and
nonpoint sources.During periods of low flow, much of
statis-
dis-
In
and
streams
aquifer
tributary
from
the
surficial
tem-
may
tributaries
its
and
1996).
River
Franklin,
the
and
(Giese
in
Suwannee
vari-
from
quality
water
on
1981)
al.,
et
(Hull
1968-1977
spe-
1996),
Mattson,
and
pH,
(Ca),
sulfate
downpH
mean
the
example,
Florida,
For
Benton,
to 5.88 at
and
or
carbon
organic
total
of
iron
dissolved
and
nitrogen,
organic
ground
and
water
surface
from
water
sources.
The effect of increasing ground-water
discharge in
a downstream direction on the chemistry of water in
the Suwannee River in a downstream
direction
is
shown in a Durov diagram (Figure 3). This diagram is
similar
to a quadrilinear
Piper diagram
with the
two
the
from
points
intersection
the
anions, in milHequivalents
per liter)
or
cations
of
sum
the
to
anion
or
cation
Piper triangles (showing the relative contribution of a
particular
ered significant at an alpha (a) value, or level of significance, of 0.05 or less.
that
exception
consid-
positive
A
was
variables
correlation.
two
of
water
equal
(Iman
given
were
variables
two
the
on
between
effect
relation
at
2).
4.20
from
concentrations
the
total
C),
contribution
non parametric
observations
All
between
1983).
relation
ing
Conover,
of calcium
(HC03),
and
with distance
decreased in a downstream direction (Table 2). Trends
in water chemistry are consistent with the relative
weight so that any extreme values will not have a disproportionate
and concentrations
(Table
stream
increased
while
(TO
River
tic measures the strength of an increasing or decreas-
negative
streams
(Hornsby
conductance,
conductance
specific
and
of
pH
This
reverse
influence
during
collected
1989-1995
cific
deter-
to
used
was
statistic
Rho
of
degree
correlation
levels.
some
to
relative
The
data
ty
and
medi-
and
distributed,
normally
not
were
generally
data
lations.
Spearman's
water
conditions
were
techniques
Nonparametric
statistical
between Alapaha
stage and water levels in a nearby well and the
ground
high-flow
Suwannee Springs, Florida, and to 7.31 at Wilcox,
Florida (Hornsby and Mattson, 1981). Accompanying
these increases, the concentrations
of sodium (Na),
potassium (K), and nitrate (N03) increased slightly,
these techniques do not require equal variances.
Hypothesis tests were used to determine if observed
differences in concentrations or water levels are due
to random variability or statistically significant popu-
with
when
magnesium
(Mg), bicarbonate
(S04) clearly
show an increase
area in Lafayette
used for analysis of water-quality data, because these
mine the degree of correlation
sinks
of
flow
peaks
cause
Flood
to
made
the
present
to
used
were
Boxplots
constituents.
County.
study
River
become
ous sources that contribute
water to the Suwannee
River are indicated by downstream changes in river
water chemistry. Based on an analysis of water-quali-
an, the 10th, 25th, 75th, and 90th percentiles, and
probable outliers of nitrate concentrations in ground
from an agricultural
from
originates
Suwannee
the
into
using
represent
to
were
attempts
accountfor differing depths of wells, nonsimultaneous
measurements
of water levels, variable
effects of
pumping, and changing climatic influence.
Descriptive and nonparametric
statistics were used
to summarize the concentrations of selected chemical
water
flow origidischarge
basin were significantly attenuated as a result of substantial subsurface storage provided by the karstic
nature of the Upper Floridan aquifer (Giese and
Franklin, 1996).
constructed
generalized
were
to which water would rise in
No
wells.
the altitude
cased
tightly
synoptically
that
were
data
water-level
contours
River subbasin,
river
Springs
that normally
low-
and
porarily
during
1984
May
measured
and
wells
April
325
in
for
data
conditions
flow
water-level
from
potentiometric
water
of
the
charge
the lower Suwannee
nates from springs.
flow conditions in December1990 and January 1991.
The
River in the upper part of
high-
during
measured
were
that
wells
226
for
data
are described by Hull et al. (1981) and Environmental
Services and Permitting, Inc. (1995).
Maps of the potentiometric surface of the Upper
Floridan aquifer were constructed using water-level
basin
the water in the Suwannee
River
Suwannee
the
from
samples
water
of
analysis
1992; Maddox et al., 1992). Methods of collection and
system.
(Katz,
FGWQMNP
the
for
compiled
and
collected
Katz, DeHan, Hirten,
are plotted
against two additional variables (pH and TOC, in this
low
near
concen-
pH,
low
water
river
high
The
type.
the
in
relatively
water
and
3)
(Figure
2),
mixed
a
in
(Table
TOC
of
solids
results
dissolved
ASSOCIATION
RESOURCES
1242
WATER
stream, the contribution from ground water increases,
AMERICAN
any
system
THE
aquifer
from
at
water
River
surficial
of
Suwannee
discharge
by
the
OF
wetlands,
the
of
affected
quality
and
Benton, Florida, indicate the relatively large contribution of water from tributary
streams and runoff
originating
in swamps and wetlands. Further down-
JOURNAL
JAWRA
swamps
is
water
location
given
The
trations
Water-Quality and Water-Level Evidence for Ground
Water / Surface WaterInteractions in the Basin
which
case) in a<ljacent scaled rectangles. For instance, near
the headwaters of the river (near Benton, Florida),
there is no dominant cation or anion in river water,
RESULTS AND DISCUSSION
Katz, DeHan, Hirten,
The hydrogeologywithin the SuwanneeRiver basin
is directly related to the physiography.The northern
part of the basin is located in the Northern Highlands, an area characterizedby land surface altitudes
highest stages for the Suwannee River and its tributaries.
Highlands
m.
70
to
up
Northern
the
in
elevations
are
reaching
common
of the intermediThe
the
is
Gulf
souththe
which
in
division,
lies
The
reflect
rainwater.
of
system.
features
basin
physiographic
River
aquifer
water
infiltration
the
surface
surficial
the
Suwannee
the
Lowlands
of
in
of
retard
and
part
table
levels
tem
water
water
10
to
3
from
thickness
in
ranges
age,
in
Coastal
ern
consists of undifferentiated sands and clays that are
Miocene
because clayey sediments
ate confining unit underlie the surficial aquifer sys-
The major hydrogeologic
units in the Suwannee
River basin include the surficial aquifer system, the
intermediate
confining unit, and the Upper Floridan
aquifer (Table 1). The surficial aquifer system, which
post
m,
features
water
Surface
30
of the Suwannee River
than
Framework
greater
Hydrogeologic
Basin
and Catches
and
land
near
or
originates
River
Suwannee
The
underground
that
stream
or
zone.
disappears
river
every
transition
this
Lowlands
Coastal
Gulf
the
in
ground
above
Upper
the
of
limestone
the
incised
has
it
artesian
by
supplied
is
2)
(Figure
rivers
Fe
Santa
The Suwannee River originates in the Okefenokee
Swamp area of south Georgia and flows southward for
approximately 390 km to the Gulf of Mexico. Near the
headwaters,
the channel
is incised
in sandy
clays and clayey sandsthat overlie the carbonaterock
1240
JouRNAl.
water
surface
Hydrology of the Suwannee River
river's
basin.
River
between
Suwannee
the
interactions
in
spring flow.
below
m
380
than
more
to
area
study
the
of
land surface in the northern part of the study area
(Ceryak et ai., 1983). Solution features (sinkholes,
solution conduits, springs) characteristic of karst
areas provide the opportunity for direct hydraulic and
water
Floridan aquifer. The baseflow for the Suwanneeand
from
ranges
aquifer
Floridan
Upper
the
in
part
ern
approximately 300 m below land surfacein the south-
geochemical
Highlands
River,
crosses
Northern
Suwannee
in
the
it
as
Eocene
of
dolomite
and
limestone
of
consists
because
aquifer
Floridan
the
of
part
uppermost
the
remains
Floridan
Upper
The
1988).
(Scott,
m
100
exceed
aquifer,
system,
water
age.The Upper Floridan aquifer is the primary source
for industrial, agricultural, and municipal use in the
SuwanneeRiver basin in Florida. The base of potable
ground
are separated
of
part of the Suwannee
River basin in Florida. The thickness of the intermediate confining unit in this geographic region may
JAWRA
and Lowlands
by a topographicbreak referred to as the Cody Scarp
(Puri and Vernon, 1964). With the exception of the
Northern
sediments
in the northeastern
the
under
siliclastic
only
of
present
is
composed
is
and
age
unit
Miocene
fining
surface. The Highlands
Highlands
at
rock
carbonate
of
presence
the
and
con-
intermediate
The
1991).
(Scott,
basin
the
of
tion
m
por-
easternmost
the
in
m
18
to
15
reach
may
but
m
characterizedby land altitudes that are less than 30
OF THE AMERICANWATERRESOURCESASSOCIATION
Katz. DeHan.Hb"ten.and Catches
Figure 1. GeneralizedHydrogeologicSectionin the SuwanneeRiver Basin ShowingKarst Features
selected
for
of
a pilot
Task Force on Moni-
toring Water Quality (lTFM). The study was designed
to
were
related
gaps
issues
that
pro-
ITFM
the
man-
to
way
effective
highly
a
as
recommended
been
age water resources because this approach integrates
ponents
health
Europe,
com-
for
national
(ITFM,
need
the
hydrologic
recognized
by
systems
various
have
Interagency
the
of
monitoring
of a watershed
(United
Nations
1993;
water
studies
surface
independent
other
and
groups
Several
water
international
integrated
and
1995).
ground
this
Floridan
has
approach
watershed
The
1995).
(lTFM,
itoring
these gaps be addressed by developing an integrated,
voluntary, nationwide strategy for water-quality mon-
in
by
recommended
was
it
and
grams
found to exist in State and Federal monitoring
This paper evaluates hydrologic and water-quality
data for the Suwannee River basin in Florida to better understand the interactions
between ground
water and surface water within the context of watershed management concerns. Three critical watershed
management issues are addressed in the paper: (1)
the degree of hydrochemical interaction between
ground water and surface water in the basin, (2) the
coincidence of ground water subbasins and surface
water subbasins under different hydrologic conditions, and (3) the ability of natural processes to
reduce elevated concentrations of nitrate in the Upper
presented
key
Information
addressing
in
resources.
water
agencies,
monitoring
local
to evaluate the effectiveness of current monitoring
programs, coordinated among Federal, State, and
the Surface and Subsurface.
approaches
study by the Intergovernmental
one
was
Florida
in
nationwide
of Water Between
The
watersheds
the Exchange
aquifer.
several
basin
River
Suwannee
The
That Facilitate
paper provide a framework for evaluating the importance of the interactions between ground water and
surface water in a watershed context that can be
extrapolated to other watersheds within Florida and
nationwide where ground water and surface water
systems
are
intimately
linked.
for evaluating
ecosystem
Economic
Commission
for
Ecosystem
Management
JAWRA
1238
JouRNAL
Task Force, 1995; Council of State Governments,
1995).
OF THE AMERICANWATERRESOURCESASSOCIATION