Tidal flushing of intracoastal bays Corpus Christi Bay, Texas Gulf coast, Sarasota Bay, Gulf coast of Florida


Smith, N.P.

Contributions in Marine Science 25(25): 1-12

1982


A numerical model is derived which describes the flushing of a coastal bay through tidal exchanges with the adjacent continental shelf. An expression for the renewal of bay water as a function of the number of elapsed tidal cycles involves a series of binomial coefficients which is equal in length to the number of tidal cycles. The model describes temporal variability in bay salinity,- or any other measure of water quality, and indicates an asymptotic approach to a final value equal to that characteristic of shelf waters. The model is applied to Corpus Christi Bay, along the central Texas Gulf coast, and to Sarasota Bay, on the Gulf coast of Florida. For tidal processes alone, and ignoring significant beat frequencies in the local tides, the model suggests that 50% of the water of Corpus Christi Bay will be renewed in from 155 to 1,400 tidal cycles, assuming 90% and 10% mixing of flood tide waters within the bay, respectively. It is concluded that meteorologically forced exchanges and, to a lesser extent, fresh water run-off are significant in supplementing the tidal flushing of Corpus Christi Bay and maintaining water quality. Model results suggest that tidal flushing is considerably more effective in Sarasota Bay. With 50% mixing of flood tide waters, half of the bay water will be renewed in 4 tidal cycles, and essentially all of the bay water will be replaced within 30 tidal cycles.

Contributions
in
Marine
Science.
(1982)
Vol.
25:1-12.
TIDAL
FLUSHING
OF
INTRACOASTAL
BAYS
Ned
P.
Smith
Harbor
Branch
Foundation,
Inc.
R.R.
1,
Box
196,
Fort
Pierce,
FL
33450
Harbor
Branch
Foundation,
Contribution
No.
303
ABSTRACT
A
numerical
model
is
derived
which
describes
the
flushing
of
a
coastal
bay
through
tidal
exchanges
with
the
adjacent
continental
shelf.
An
expression
for
the
renewal
of
bay
water
as
a
function
of
the
number
of
elapsed
tidal
cycles
involves
a
series
of
binomial
coefficients
which
is
equal
in
length
to
the
number
of
tidal
cycles.
The
model
describes
temporal
variability
in
bay
salinity,
-
or
any
other
measure
of
water
quality,
and
indicates
an
asymptotic
approach
to
a
final
value
equal
to
that
characteristic
of
shelf
waters.
The
model
is
applied
to
Corpus
Christi
Bay,
along
the
central
Texas
Gulf
coast,
and
to
Sarasota
Bay,
on
the
Gulf
coast
of
Florida.
For
tidal
processes
alone,
and
ignoring
significant
beat
frequencies
in
the
local
tides,
the
model
suggests
that
50%
of
the
water
of
Corpus
Christi
Bay
will
be
renewed
in
from
155
to
1,400
tidal
cycles,
assuming
90%
and
10%
mixing
of
flood
tide
waters
within
the
bay,
respectively.
It
is
concluded
that
meteorologically
forced
exchanges
and,
to
a
lesser
extent,
fresh
water
run-off
are
significant
in
supplementing
the
tidal
fl
ushing
of
Corpus
Christi
Bay
and
maintaining
water
quality.
Model
results
suggest
that
tidal
flushing
is
considerably
more
effective
in
Sarasota
Bay.
With
50%
mixing
of
flood
tide
waters,
half
of
the
bay
water
will
be
renewed
in
4
tidal
cycles,
and
essentially
all
of
the
bay
water
will
be
replaced
within
30
tidal
cycles.
Accepted
24
March
1982
INTRODUCTION
An
understanding
of
tidal
processes
forms
the
basis
of
investigations
of
mixing
within
estuarine
waters,
the
exchange
of
water
between
an
estuary
and
the
adjacent
continental
shelf,
and
hence
the
flushing
and
resulting
water
quality
of
an
estuary.
Sufficiently
long
time
series
have
been
obtained
in
recent
years
to
provide
information
on
the
supplementary
role
of
meteorological
forcing
(Weisberg
1976;
Smith
1977,
1979;
Elliott
and
Wang
1978),
and
results
indicate
that
these
effects
can
be
significant,
especially
in
coastal
regions
with
characteristically
low
amplitude
tides.
But
weather
processes
are
no
more
dependable
than
they
are
predictable.
At
the
very
least,
tidal
processes
provide
a
baseline
value.
During
times
of
prolonged
calm,
tidal
exchanges
may
provide
the
only
means
by
which
water
quality
in
an
estuarine
system
is
maintained.
Tidal
flushing
can
be
quantified
in
any
of
several
ways,
depending
upon
which
simplifying
assumptions
are
justified
in
a
particular
estuarine
setting.
Early
studies
in
drowned
river
valley
type
estuaries
involved
a
tidal
prism,
4
Ned
P
Smith
Because
the
effective
tidal
prism
can
be
quite
small
relative
to
the
total
volume
of
the
bay,
many
tidal
cycles
may
have
to
be
considered
before
a
significant
fraction
of
the
bay
is
fl
ushed
by
tidal
processes.
This
presents
computational
difficulties,
since
n!
becomes
too
large
to
be
handled
by
many
computing
systems
for
calculations
corresponding
to
time
intervals
on
the
order
of
a
month
(with
predominantly
diurnal
tides).
The
DEC
PDP
11/34
computer
used
in
this
study
could
not
simulate
tidal
fl
ushing
for
more
than
32
tidal
cycles.
Thus,
calculations
were
carried
out
in
groups
of
ten
tidal
cycles,
with
the
resulting
bay
-shelf
salinity
differences
after
any
ten
cycles
serving
as
a
new
AS
for
the
next
ten
-cycle
calculation.
APPLICATION
OF
THE
MODEL
The
numerical
model
can
be
applied
to
any
intracoastal
bay
for
which
the
effective
tidal
prism,
the
low
-tide
volume
and
the
degree
of
mixing
within
the
bay
is
either
known
or
can
be
estimated.
Here,
the
model
is
used
to
investigate
tidal
flushing
in
Corpus
Christi
Bay,
in
the
northwestern
corner
of
the
Gulf
of
Mexico
(Fig.
1),
and
Sarasota
Bay,
along
the
Gulf
coast
of
Florida
(Fig.
2).
lbgether,
these
two
bays
represent
opposite
extremes
in
terms
of
the
effectiveness
of
tidal
fl
ushing.
Tidal
conditions
in
Sarasota
Bay
have
not
been
quantified
particularly
well,
but
available
information
is
adequate
to
suggest
that
tidal
fl
ushing
is
considerably
more
efficient
in
this
bay
than
in
Corpus
Christi
Bay.
97°30'
28°00'
ARANSAS
PASS
CORPUS
CHRISTI
BAY
1
0
5
10Km
97°00'
+27°40'
GULF
OF
MEXICO
Fm.
1.
Corpus
Christi
Bay
and
the
Aransas
Pass.
Arrow
in
insert
map
shows
the
location
of
the
study
area
along
the
central
Texas
Gulf
coast
in
the
northwestern
Gulf
of
Mexico.
Tidal
Flushing
5
LONGBOAT
PASS
0
2
4
6
8
10
Km
GULF
OF
MEXICO
27°16'
82°42'
Fm.
2.
Sarasota
Bay
and
connecting
passes.
Arrow
in
the
insert
map
shows
the
location
of
the
study
area
along
the
Gulf
coast
of
Florida
in
the
eastern
Gulf
of
Mexico.
27°28'
+
82°34'
SARASOTA
<'•
BAY
NEW
PASS
t,
%
.
BIG
SARASOTA
PASS
A.
Corpus
Christi
Bay,
Texas
Previous
work
done
in
Corpus
Christi
Bay
(Smith
1977)
provides
some
of
the
values
needed
to
run
the
model
over
an
appropriate
range
of
tidal
cycles.
At
the
same
time,
the
physical
setting
of
the
bay
is
well
suited
for
illustrating
some
of
the
difficulties
that
may
arise
with
the
application
of
the
model
to
certain
situations.
The
bay
is
approximately
circular,
with
east
-west
and
north
-
south
dimensions
of
about
26
and
20
km,
respectively.
The
surface
area
of
the
bay
is
approximately
297
km
2
,
and
mid
bay
depths
are
on
the
order
of
3.5
m.
Collier
and
Hedgpeth
(1950)
have
estimated
the
mean
low
water
volume
of
Corpus
Christi
Bay
to
be
1,143
x
10'
m
3
.
It
is
noteworthy
that
the
bay
is
connected
to
the
Gulf
of
Mexico
by
a
dredged
ship
channel
which
itself
contains
approximately
37
x
10°
m
3
of
water.
Tides
along
the
northwestern
rim
of
the
Gulf
of
Mexico
are
mixed
but
principally
diurnal,
with
a
form
number
of
2.5
at
the
Aransas
Pass
jetties,
and
over
6.0
in
the
bay
itself
(Smith
1974).
The
tidal
range
in
the
bay
varies
from
a
few
centimeters
at
times
of
equatorial
tides
to
as
much
as
30
cm
during
tropic
tides.
A
harmonic
analysis
of
the
hour
-by
-hour
variation
of
the
bay
surface
above
a
reference
datum
(Smith
1977)
quantified
the
tidal
prism
associated
with
each
of
the
principal
tidal
constituents.
Here,
we
shall
work
initially
with
a
single,
hypothetical
tidal
constituent
which
has
the
same
long-term
effect
as
the
several
principal
tidal
constituents
working
in
concert.
Later,
we
shall
discuss
the
effect
of
the
fortnightly
tidal
cycles
in
fl
ushing
the
bay.
8
Ned
P.
Smith
40.
-
30.
-
TIDAL
WATER
LEVELS
CCENTIMETERS)
20.
-
10.
-
0.
-
10.
-
-
20.
-
-
30.
I
I
•1
-1
10.
1
4
7
10
13
16
19
22
25
28
31
FIG.
5.
Time
-plot
of
water
levels
for
Sarasota
Bay
varying
in
response
to
tidal
exchanges
only.
Amplitudes
were
taken
from
Zetler
and
Hansen
(1970)
for
Anna
Marie,
and
scaled
down
to
maximum
diurnal
ranges
reported
by
McNulty,
et
od.
(1972).
Local
phase
angles
were
not
incorporated
into
the
calculations.
Horizontal
axis
is
time
in
days.
DISCUSSION
The
time
-plot
of
tidal
bay
volume
(Fig.
3)
is
useful
for
putting
the
tidal
fl
ushing
of
Corpus
Christi
Bay
in
a
proper
perspective.
Specifically,
as
a
result
of
the
fortnightly
beat
frequency
of
the
dominant
K,
and
0
tidal
constituents,
tidal
fl
ushing
takes
on
a
cyclical
behavior,
and
there
are
periods
of
8-9
days
during
which
little
or
no
water
from
the
Gulf
enters
the
bay,
or
vice
versa.
Rather,
the
co
-oscillating
tidal
motions
result
in
bay
or
Gulf
water
being
stored
temporarily
in
the
channel
before
returning
to its
place
of
origin
during
the
last
half
of
the
tidal
cycle.
In
this
physical
setting,
then,
tidal
fl
ushing
appears
to
occur
in
bursts.
The
situation
is
similar
for
Sarasota
Bay,
though
with
no
long
channels
connecting
the
inner
shelf
with
the
bay,
it
is
probable
that
at
least
some
fl
ushing
occurs
on
each
tidal
cycle.
Effects
are
still
highly
variable,
however,
over
a
synodic
month.
The
effect
of
a
mixed
tide
has
received
little
attention
in
discussions
of
tidal
fl
ushing
in
estuaries.
A
thorough
treatment
of
tidal
fl
ushing
must
touch
at
least
briefly
on
the
supplementary
role
played
by
meteorological
forcing.
Here
we
must
focus
upon
Corpus
Christi
Bay,
as
little
work
of
this
type
has
been
conducted
in
Sarasota
Bay.
The
central
Texas
Gulf
coast
is
a
region
of
characteristically
Tidal
Flushing
9
strong
winds.
The
International
Airport
at
Corpus
Christi
is
listed
by
the
National
Weather
Service
as
the
third
windiest
airport
in
the
country,
with
a
scalar
wind
speed
averaging
24.3
km/h.
Both
windstress
(Smith
1977)
and
variations
in
atmospheric
pressure
(Smith
1979)
are
capable
of
producing
bay
-shelf
exchanges
equal
in
importance
to
all
but
the
principal
tidal
constituents.
In
one
instance,
the
rapid
reversal
and
increase
in
windstress
associated
with
a
frontal
passage
in
February,
1972,
removed
approximately
10%
of
the
volume
of
the
bay
in
a
period
of
56
hours.
The
renewal
rates
given
in
the
preceding
section
therefore
represent
a
baseline
(minimum)
value,
which
may
in
fact
be
enhanced
substantially
even
by
unexceptional
meteorological
events.
It
is
probable
that
the
degree
of
mixing
associated
with
the
slower
filling
and
draining
by
meteorological
forcing
may
be
greater,
since
there
is
more
time
available
for
water
to
be
caught
up
in
the
internal
circulation
of
the
bay.
Another
source
of
fl
ushing
is
the
fresh
water
entering
the
bay,
moving
through
in
one
or
more
gyres
(perhaps
maintaining
some
of
the
semi-
permanent
features
of
bay
circulation
by
creating
barotropic
or
baroclinic
pressure
gradients
within
the
bay),
and
finally
being
exported
onto
the
continental
shelf.
In
the
case
of
Corpus
Christi
Bay,
the
multi
-annual
mean
fresh
water
influx
was
found
to
be
20.6
m
3
/s
over
the
period
1951-1968
(Diener
1975).
With
a
surface
area
of
297
km
2
,
an
excess
evaporation
over
precipitation
of
0.59
cm/day
would
be
required
to
remove
all
this
fresh
water
from
the
bay
before
it
moved
through
and
out
onto
the
shelf.
It
is
noteworthy
in
this
regard
that
Smith
(1981)
has
calculated
an
evaporation
rate
of
0.19
cm/day
from
the
surface
of
upper
Laguna
Madre,
immediately
south
of
Corpus
Christi
Bay
(Fig.
1),
during
a
68
-day
study
in
the
winter
of
1973-74.
The
excess
evaporation
over
precipitation
during
this
time
was
0.08
cm/day.
This
value
is
in
good
agreement
with
calculations
based
upon
climatological
maps
for
the
lexas
coastal
zone
(Texas
General
Land
Office
1975,
Arbingast,
et
al.
1976).
Evaporation
from
the
bay
surface
is
estimated
to
exceed
direct
precipitation
by
anywhere
from
46-74
cm/year,
which
is
equivalent
to
0.13-0.20
cm/day.
This
appears
to
leave
a
significant
fraction
of
the
fresh
water
entering
the
bay
available
for
a
fl
ushing
role.
In
fact,
if
three
-fourths
of
the
fresh
water
entering
the
bay
moves
through
and
out
onto
the
shelf
without
evaporating,
856
days
would
be
needed
to
displace
50%
of
the
bay
water.
For
comparison,
the
model
predicts
that
856
tidal
cycles
would
renew
88%
of
the
bay
water,
assuming
50%
mixing
of
the
fl
ood
tide
(Fig.
4).
Thus,
ignoring
the
nature
of
the
movement
of
fresh
water
through
the
bay,
one
may
tentatively
conclude
that
fl
ushing
by
fresh
water
is
significant,
but,
on
the
average,
it
appears
to
play
a
secondary
role
to
tidal
exchanges
in
this
physical
setting.
The
average
fresh
water
inflow,
however,
may
not
be
a
particularly
good
measure
of
fresh
water
inflow
at
a
given
time.
This
is
especially
true
along
the
central
Texas
Gulf
coast,
where
normally
semi
-arid
conditions
can
give
way
to
temporarily
heavy
rains.
This
"flashiness"
in
fresh
water
run-off
generally
occurs
over
time
scales
on
the
order
of
a
few
days
to
perhaps
a
10
Ned
P
Smith
week,
but
some
values
from
the
U.S.
Geological
Survey
stream
gage
on
the
Nueces
River
(Diener
1975)
are
noteworthy.
Ignoring
hurricane
-related
rains,
which
constitute
an
extreme
case,
mean
monthly
discharges
in
April
and
May,
1968,
were
2.9
m
3
/s
and
124
ma/s,
respectively.
The
effect
of
excessive
fresh
water
inflow
is
to
create
both
a
barotropic
and
a
baroclinic
pressure
gradient.
The
former
aids
the
ebbing
of
water
out
of
the
bay;
the
latter
enhances
mixing
of
water
within
the
bay.
Rapid
changes
of
fresh
water
discharge
occur
in
Sarasota
Bay
as
well,
but
they
are
less
extreme.
Furthermore,
because
the
drainage
area
of
the
principal
tributary
(Phillipi
Creek)
is
only
62
km
2
,
and
mean
monthly
discharge
rates
are
generally
between
0.1
and
1.9
m
3
/s,
the
effects
of
even
extreme
fl
ow
rates
would
be
relatively
small.
The
rather
lengthy
time
intervals
postulated
for
the
renewal
of
water
in
Corpus
Christi
Bay
by
tidal
exchanges
and
the
mean
fresh
water
runoff
implies
that
exchanges
in
response
to
meteorological
and
hydrologic
events
must
be
dominant
—if
the
bay
is
well
fl
ushed.
It
would
appear
that
the
bay
is
in
fact
well
fl
ushed,
since
bay
-shelf
salinity
differences
are
on
the
average
negligible,
while
the
sum
of
direct
precipitation
and
runoff
is
on
the
order
of
4-6
times
greater
than
evaporation.
The
mean
salinity
of
bay
water
samples
taken
between
1964
and
1968
was
found
to
be
approximately
31.4
parts
per
thousand
(ppt)
(Smith
1978).
Surface
samples
from
a
station
14
km
offshore
during
1976
and
1977
were
found
to
average
31.5
ppt
(Smith
1980).
Behrens
(1966)
has
documented
long
-period
salinity
cycles
in
Texas
intracoastal
waters,
extending
over
time
scales
of
several
years.
Thus,
while
a
compari-
son
of
mean
bay
and
shelf
salinities
computed
from
different
time
intervals
is
not
strictly
valid,
the
available
information
suggests
that
on
the
average
the
difference
in
the
salinity
of
bay
and
shelf
waters
is
kept
to
a
minimum.
This
implies
that
there
is
a
relatively
active
exchange
of
water,
presumably
in
response
to
discrete
events.
It
is
important
to
note
that
the
development
of
the
model
in
terms
of
salinity
does
not
restrict
its
application
to
other
indicators
of
water
quality,
or
to
any
conservative
hydrographic
variable.
Thus,
the
half-life
of
any
dissolved
or
suspended
substance
for
which
bay
-shelf
differences
exist
would
seem
to
be
on
the
order
of
9
months
for
Corpus
Christi
Bay,
and
several
days
(depending
upon
tidal
conditions)
for
Sarasota
Bay
—when
only
tidal
processes
are
considered.
These
time
estimates
can
change
appreci-
ably,
of
course,
when
information
becomes
available
to
suggest
that
mixing
of
fl
ood
tide
waters
differs
significantly
from
the
50%
value
used
here
for
comparison
purposes.
Any
numerical
model
of
tidal
fl
ushing
is
bound
to
involve
simplifying
assumptions
of
one
sort
or
another
to
facilitate
the
evaluation
of
the
appropriate
equations.
In
this
case,
aside
from
the
substitution
of
one
hypothetical
tidal
constituent
for
the
several
major
constituents
which
combine
to
produce
the
distinct
beat
frequencies,
the
assumption
that
the
net
salt
fl
ux
into
the
bay
on
any
given
tidal
cycle
is
uniformly
distributed
throughout
the
bay
prior
to
the
next
tidal
cycle
is
clearly
compromising
Tidal
Flushing
11
reality.
Three
years
of
hydrographic
data
from
Corpus
Christi
Bay
(Holland
et
al.
1975)
show
that
significant
horizontal
gradients
may
exist
at
any
time
of
year.
Furthermore,
to
the
extent
that
gyres
dominate
the
internal
circulation
of
the
bay,
there
may
exist
isolated
regions
which
are
little
affected
by
tidal
fl
ushing.
Refinements
to
the
simple
techniques
presented
here
can
be
incorporated
when
the
hydrography
and
dynamics
of
coastal
bays
are
understood
better.
ACKNOWLEDGMENTS
I
would
like
to
express
my
appreciation
to
Mr.
Howard
Marshall,
Head
of
Research
and
Development
at
Harbor
Branch
Foundation,
for
his
continued
interest
in
this
study;
to
Ms.
Carolyn
Baruch
for
her
help
in
providing
the
computer
program
used
to
calculate
renewal
rates;
and
to
Dr.
George
Ward,
for
his
helpful
review
of
the
first
version
of
the
manuscript.
LITERATURE
CITED
ARBINGAST,
S.
A.,
L.
G.
KENNAMER,
R.
H.
RYAN,
J.
R.
BUCHANAN,
W.
L.
IIEZI.EP,
L.
T.
ELLIS,
T.
G.
JORDAN,
C.
T.
GRANGER
and
C.
P
ZLATKOVICII.
1976.
Atlas
of
Texas.
The
Univ.
of
Texas,
Bureau
of
Business
Research.
179pp.
BEHRENS,
E.
W.
1966.
Surface
salinities
for
Baffin
Bay
and
Laguna
Madre,
Texas,
April
1964
March
1966.
Publications
of
the
Institute
of
Marine
Science,
University
of
Texas.
11:168-173.
BROWN,
W.
S.
and
E.
ARELLANO.
1981.
The
application
of
a
segmented
tidal
mixing
model
to
the
Great
Bay
Estuary,
N.
H.
Estuaries.
3:248-257.
COLLIER,
A.
and
J.
W.
HEDGPETH.
1950.
An
introduction
to
the
hydrography
of
tidal
waters
of
Texas.
Publications
of
the
Institute
of
Marine
Science,
University
of
Texas.
1(2):121-194.
DIENER,
R.
A.
1975.
Cooperative
Gulf
of
Mexico
estuarine
inventory
and
study
—Texas:
area
description.
NOAA
Technical
Report
NMFS
CIRC-393.
129pp.
DYER,
K.
R.
and
P.
A.
Taylor.
1973.
A
simple
segmented
prism
model
of
tidal
mixing
in
well
-
mixed
estuaries.
Estuarine
and
Coastal
Marine
Science.
1:411-418.
ELLIOTT,
A.
J.
and
D
-P
WANG.
1978.
The
effect
of
meteorological
forcing
on
the
Chesapeake
Bay:
the
coupling
between
an
estuarine
system
and
its
adjacent
coastal
waters.
pp.
127-
146.
In
J.
C.
J.
Nihon!
(Ed.)
Hydrodynamics
of
Estuaries
and
Iqords.
Elsevier
Scien.
Publ.
Co.,
Amsterdam.
HOLLAND,
J.
S.,
N.
MACIOLEK,
R.
KALKE,
L.
MULLINS
and
C.
II.
OPPENHEIMER.
1975.
A
benthos
and
plankton
study
of
the
Corpus
Christi,
Copano
and
Aransas
Bay
systems.
Third
Year
Rept.,
Univ.
of
Texas
Marine
Science
Inst.,
174
pp.
KETCHUM,
B.
H.
1951.
The
exchanges
of
fresh
and
salt
waters
in
tidal
estuaries.
Journal
of
Marine
Research.
10:18-38.
LEE
T.
H.
and
C.
ROOTH.
1972.
Exchange
processes
in
shallow
estuaries.
Proceedings,
Offshore
Technol.
Conf.,
May
1972,
Paper
ETOC
1703,
12
pp.
McNULTY,
J.
K.,
W.
N.
LINDALL
and
J.
E.
SYKES.
1972.
Cooperative
Gulf
of
Mexico
estuarine
inventory
and
study,
Florida:
Phase
1,
Area
Description.
NOAA
Technical
Report
NW'S
CIRC-368,
126pp.
SMITH,
N.
P
1974.
Intracoastal
tides
of
Corpus
Christi
Bay,
Contributions
in
Marine
Science.
18:205-219.
1977.
Meteorological
and
tidal
exchanges
between
Corpus
Christi
Bay,
Texas,
and
the
northwestern
Gulf
of
Mexico.
Estuarine
and
Coastal
Marine
Science.
5:511-520.
1978.
Tidal
and
long
-period
exchanges
between
upper
Laguna
Madre
and
Corpus
Christi
Bay,
Te
xas.
TALUS,
Texas
A
&
I
University
Studies.
11:39-51.
1979.
Meteorological
forcing
of
coastal
waters
by
the
inverse
barometer
effect.
Estuarine
and
Coastal
Marine
Science.
8:149-156.
12
Ned
P
Smith
1980.
On
the
hydrography
of
shelf
waters
off
the
central
Texas
Gulf
coast.
Journal
of
Physical
.Oceanography.
10:806-813.
1981.
Energy
balance
in
a
shallow
seagrass
flat
for
winter
conditions.
Limnol-
ogy
and
Oceanography
26:482-491.
TEXAS
GENERAL
LAND
OFFICE.
1975.
Physiography
and
Climate
Map,
Plate
1A,
Upper
Te
xas
Coastal
Region.
Coastal
Management
Program,
Austin,
Te
xas.
WARD,
G.
H.
1980.
Hydrography
and
circulation
processes
of
Gulf
estuaries.
183-215.
In
P.
Hamilton
and
K.
MacDonald,
(Eds.)
Estuarine
and
Wetland
Processes.
Plenum
Publ.
Co.,
New
York.
WEISBERG,
R.
H.
1976.
A
note
on
estuarine
mean
fl
ow
estimation.
Journal
of
Marine
Research.
34:387-394.
WOOD,
T.
1979.
A
modification
of
existing
simple
segmented
tidal
prism
models
of
mixing
in
estuaries.
Estuarine
and
Coastal
Marine
Science.
8:339-347.
ZETLER,
B.
and
D.
V.
HANSEN.
1970.
Tides
in
the
Gulf
of
Mexico
—a
review
and
a
proposed
program.
Bulletin
of
Marine
Science.
20:57-69.