CATENA
V O ~ . 20,
p. 469-493
Cremlingen 1993
Hydrology of Some Tidal Channels in
Estuarine Marshland Near San Francisco
L.B. Leopold, J.N. Collins & L.M. Collins
Abstract
Measurements of velocity, depth, discharge, and slope were simultaneously
made at ten gages along a natural estuarine channel 19,000 feet in length in
Petaluma Marsh, California. Along the
study reach the channel decreases from
a width of 47 feet at its mouth to nearly
zero a t its headward extent, with accompanying decrease in depth. Though gage
height varies with time in a smooth sinusoidal manner a t all stations, this is
not true for velocity, discharge, or slope.
Velocity is rather constant for long periods in the ebb cycle and differs but little along the length of the channel. It is
somewhat higher on ebb than on flood
tide.
At most gage sites, velocity continues one-half to one hour after the gage
height has reached its maximum or minimum value and reversed.
In this channel water surface slope is
considerably greater in the midreach of
channel than in either the mouthward
or headward reaches. Slopes vary from
less than .0001 t o about .0005 through
much of a tidal cycle. At some stages of
both ebb and flood, the upper end of the
channel has a positive slope while the
lower end a negative or adverse slope.
ISSN 0341-8162
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CATENA-All
At those times the longitudinal profile
of water surface is bow shaped or V
shaped.
1
Introduction
Despite the interest in wetland preservation and the recognition of the role
of marshes in the biologic and chemical cycling, few details have been published on the role of tidal marsh channels. These channels are those whose
origin and maintenance depend on tidal
inflow and outflow with but little contribution of runoff from terrestrial sources.
The water surface elevation in estuaries rises and falls as a function of time
in a nearly sinusoidal relation twice in
each lunar day. Along the western margin of the United States there are usually two unequal high tides and two unequal low tides in a day, which give rise
to the terms ”mean lower low water”
(MLLW) and “mean higher high water”
(MHHW). These are the arithmetic average of the elevation of the daily minimum and daily maximum height of the
tide computed over the tidal epoch, a
period of 19 years.
Because the tide rises and falls with
time as a neat sinusoidal curve, it is
often supposed that mean velocity and
probably mean water surface slope also
are sinusoidal with time. Our d a t a show
this supposition t o be incorrect. Few di-
I n t e r d i s c i p l i n a r y J o u r n a l of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Leopold, Collins & Collins
470
rect measurements of either are available
MLLW
Mean low water (MLW)
Mean tide (MSL)
Mean high water (MHW)
Mean higher hkh'water (MHHW)
in the abundant literature on estuaries.
Wishing to understand better the role of
channels of different sizes in the development and maintenance of marsh lands,
a study was made of one major channel and some of its minor tributaries in
Petaluma Marsh.
2
Location and general
description
The great estuary that opens to the Pacific Ocean through the Golden Gate
was once a broad flood plain of several major and minor rivers draining
the Sierra Nevada and the San Joaquin
Valley. With the rise of sea level in
Holocene time the early river valley was
drowned and many areas bordering the
flooded valley became tidal marshlands.
Most of them have been diked or drained
for urban development, for agriculture,
or for evaporation ponds in salt production. One of the few such marshes
of any size remains near the mouth of
the Petaluma River that flows south
into San Pablo Bay, the northernmost
arm of the Golden Gate Estuary. The
Petaluma Marsh is natural except for a
network of very small ditches dug for the
purpose of mosquito abatement. These
mosquito control ditches were cut in the
1970s and many have since partly filled
in with sediment or partially overgrown
with marsh vegetation.
One of the major natural channels in
Petaluma Marsh is Tule Slough, which
enters Petaluma River across from the
village of Lakeville, California.
The statistics for the NOAA tide gage
at Lakeville, California, on the Petaluma
River (gage number 9415423) for the
tidal epoch ending 1978 are as follows:
C A T E N A -A
11
1x1 t c I d i I c ip Ii 81 a ry J o II r i i R I
0f
0.0 ft
0.91 ft
1.26ft
5.81 ft
6.33 ft
The study section of the slough is
19,007 feet in length (3.60 mi or 5.80
km). In this length the width decreases
from 47 feet near the mouth to about 4
feet at the Railroad gage. A planimetric
map is shown in fig. 1.
The earliest topographic map of the
marsh was published by the U.S. Coast
Survey in 1860. It is surprising that the
mainstream channel has changed only
infinitesimally in a century, though the
smaller tributaries and unvegetated turf
pans on the marsh surface have changed
somewhat in that period. Their character and origin have been described by us
in a separate paper (Collins, Collins &
Leopold 1987).
The marsh is comprised of peat and
clay that contact ancient mudflat sediments at an average depth of 2.5 meters.
The vegetation is dominated
by pickleweed (Saiicornia virginica L.).
Near the mouth of the main channel
low natural levees occur that support
coyote brush (Bacharris pilularis) and
gum plant (Grendilia h u m i l i s ) . Slump
blocks in the channel grow cordgrass
(Spartzna joliosa). That the marsh is
mostly Salicornia agrees with the finding of Stevenson & Emery (1958) that
in Newport Bay, California, Salicornia
was mostly confined to the narrow range
of elevation 3.2 to 3.5 feet above MLW
(p. 36) when the tidal range is 3.4 feet.
That is, they found Salicornia to lie in
the zone 0.2 feet below MHW to 0.1 feet
above MHW.
5 0 IL S C I E N C E -- H Y D R O L 0 G Y
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(0.0 I
(.28 I
(.38 1
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(1.93
471
Hydrology of tidal channels, California
Fig. 1: M a p of Petaluma marsh area with station locations o n Tule Slough.
3
Channel Measurements
closure was required to measure water
surface slopes. The soft surface of the
marsh made level set-ups typically unstable so some level lines were run several times before the closure was satisfactory.
Along Tule Slough seven staff gages were
installed and two in confluent tributaries. At a later time three additional
measuring points were established to extend the network farther headward. The
We found that important errors in wazero reading of each was determined by
ter surface elevation can be caused if the
spirit levelling - connecting a series of
staff gage is not perfectly vertical. At
local benchmarks. All benchmark elevaa gage where the change in water level
tions were later tied to a common datum
was six feet, a deviation of five degrees
at the NOAA benchmark at Lakeville,
from vertical could cause an error in wajust 0.5 miles from the mouth of the Tule
ter surface elevation of .023 feet (7 mm),
Slough. The established net of benchtwice the allowable value.
marks were tied together with a maxChannel cross section was surveyed at
imum elevation error of 3.5 mm, each
leg of the level line being rerun until each staff gage as well as at other locathe required closure was attained. This tions. The cross sections are somewhat
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I n t e r d i s c i p l i n a r y Journal of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Leopold, Collins & Collins
472
Photo 1: t Photograph looking up
the channel of Tule Slough at the
Head gage.
Photo 2:
t Tule Slough at head
ward end showing Railroad gag(
ow.
CATENA-An
lntcrdlsclpllrlnty Jourlhal ot \OIL SCIENCE-HYDROLOGY
GEOMORPHOLOGY
473
Hydrology of tidal channels, California
triangular near the mouth of the slough
and get progressively more U-shaped upstream. The bank material exposed to
view at low tide is a dark grey mud,
with much clay. One sinks in to the
hips if one steps out of a boat into the
channel at low tide. Many large slump
blocks slip from the channel banks in
the downstream reaches. Photographs
of the channel are shown in photos 1
and 2.
In many places along the channel, especially on the slump blocks, bivalve
mussels including Geukensia, Isachadium, and Macoma attach themselves t o
stems and roofs of vegetation and from
the rough appearance, these colonies
must add appreciably to the hydraulic
resistance.
At each station a distance of 30 feet
along the channel was marked by stakes
at each end. For velocity measurements
orange peels were used as floats. Surface velocity near the channel center line
was computed as the time in seconds for
the float to travel 30 feet. These velocities were multiplied by 0.8 to give
an approximate value of mean velocity
in the cross section. Float measurements were made at approximately five
t o three minute intervals as required to
account for brief velocity pulses (Reed
1987). Gage height readings were taken
every two minutes. Runs were made on
several days in 1984 and 1988.
The data on gage height at each station were reduced to the same datum,
MLLW at the Lakeville (NOAA) gage.
Cross section data were related to water
stage, and with the measured velocity,
discharge was computed as a function of
time.
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4
Channel size parameters
along the slough
In fig. 2 several aspects of channel size
are plotted as a function of distance
along the main slough. The width decreases upstream in an irregular fashion
from 47 feet at mouth gage to nearly
zero feet at Railroad gage. Local narrowing at sections A and D is caused
by slump blocks on both banks. Mean
bed elevation increases upstream and is
equal to MLLW at a distance of about
6,000 feet upstream of the mouth of the
channel.
Cross-sectional area and volume of the
total prism are both measured at 1400
hours March 17, 1984, where the water
surface was at 6.7 feet above MLLW or
slightly above bankfull stage.
Cross-sectional area reflects closely
the channel width. The tidal prism
equals about 3,100,000 cubic feet (71
acre feet) at this near-bankfull condition
between the mouth and the upstream
gage. Thus, this volume would be filled
if an average of 142 cfs flowed past the
mouth gage for six hours of flood tide.
The bed of the channel is soft mud.
The only visually obvious sources of hydraulic roughness are the mussel colonies
in the shallows of the channel, and the
slump blocks along the banks that support Spartina. Slump blocks as described make the banks randomly irregular. One must merely guess at the major cause of hydraulic resistance. But
the muddy bed is not smooth. In the
relatively straight reach between mouth
and A gages, a distance of 1,240 feet,
depth measurements were taken about
five feet apart. More or less regular undulations of the bed were observed with
an average spacing between successive
high points of 96 feet with a standard
Interdisciplinary J o u r n a l of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
&-
LL
I
1
0
2
D I S T A N C E T H O U S A N D S OF F E E T
t
I
I
8
6
4
I
I
I
I O
12
14
‘1
3
VOLUME
0
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I
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LL
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0
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3
0
A
I
1
c
1
D
1
E
1
MID
1
O
4 -
w
0
I
1
GAGES
Fig. 2: Channel size parameters as f u n c t i o n o j distance along Tule Slough, cross
sectional area, channel width, m e a n bed elevation, and cumulative volume of tidal
p r i s m . Volume i s computed f o r March 17, 1984, 1400 hr., a t ws elevation of 6.7 f t
above MLLW.
deviation of 32 feet. The average width
of the reach is 36 feet so the mounds are
spaced at 2.7 widths. Their amplitude
was 1.3 feet, standard deviation 0.4 feet.
As can be seen 011 any tide chart, gage
height (water surface elevation) usually
varies through time in a smooth nearly
sinusoidal curve. Velocity does riot follow this pattern but tends to remain
rather constant for much of a tidal period as can be seen in fig. 3. For most of
C A T E N A - A n I I I t e rrl i I c i p 1 i n ary .I I> II I
18
aI
II
t
both ebb and flood flow, the stations a t
the lower and upper ends of the tlireeniile reach experienced lower velocities
than the five interinedia.te stations. This
results from the higher values of water
surface slope in the mid reach of the
channel length as will be shown lat,er.
Another aspect of velocity is its relation to stage. On fig. 4 velocity is plotted vs. water surface elevation for three
stations, Mouth, E, and Head, on April
S 0 I L S C I E N C:E-
H Y D R 0L 0 G Y
-G E O M 0 R F H 0 L 0 G Y
Hydrology of tidal channels, California
475
Fig. 3: Surface velocity at each station and gage height at M o u t h gage as f u n c t i o n
of time. The data f o r April 22 and f o r March 17 are plotted together t o approximate
a full tidal cycle.
6
I
-MHW
,xK
.
';5
MOUTH
'X
LL
3
-I
-I
1
z
A
4
m
a
>
w
1 3
W
W
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0
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a
LL
5
2
(0
n
W
+
a
3 1
0
- MLLW
-I
I
-I
I
FLOOD
I
I
I
EBB
+I
Fig. 4: M e a n velocity ut three
stations is plotted against elevation of the water surface expressed as f e e t above MLLW, f o r
A p r i l 22, 1984. Arrows indicate
the sequence through time.
V E L O C I T Y F T . PER S E C .
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7
6
1
33
a
>
m
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0
c
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DISCHARGE HEAD
0
0800
IO00
1200
1400
I600
-
A P R I L 22. 1 9 8 4
M A R C H 17.
1304
1400
1600
-400 1000
1200
Fig. 5: Discharge as a f u n c t i o n of time for three stations, M o u t h , M i d , and Head.
T h e relation i s shown f o r dates of April 2.2 and M a r c h 17, 1984. N o t e that o n the
latter date the discharge was higher because the m a x i m u m water surface elevation
was higher o n the M a r c h I7 date.
w
Hydrology of tidal channels, California
E
A
C
D
3
0
>
I
n
H
477
E
0
4
W
I
I
I
I
I
4
6
8
IO
12
r
14
D I S T A N C E THOUS. O F FEET
Fig. 6: T i m e of slack water (velocity equals zero) A p r i l 22, 1984, in comparison t o
the t i m e of minimum gage height f o r stations located a t diflerent distances along
the channel. Velocity i s zero one half t o one hour after the water surface fall has
reversed.
22, 1984. On April 22 the Head station
experienced ebb slack water at an absolute elevation about 2-1/2 feet higher
than that of the Mouth gage. On this
graph, also, it can be seen that the middle reach of the channel exemplified by
the E gage has a higher velocity than either end of the three-mile long channel.
The rise and fall of the tide tends
to be sinusoidal on the average, but
at times deviates significantly from a
smooth wave-like curve. Fig. 5 shows
that on the ebb tide of April 22, both
the Mouth gage and the Mid gage experienced a receding water level that
smoothly lowered from 0600 to 1400
when a sharp rise in water level began
Discharge is greater near the mouth at Mouth and at 1530 a similarly sharp
than upstream primarily because of the rise began at Mid gage. At both lodownstream increase in cross sectional cations discharge changed from ebb to
area. Magnitude of the discharge is more flood nearly simultaneously with the redependent on the maximum height to versal of water surface change.
which the water rises than on the range
of stage of a particular tidal cycle. The
On March 17 the flood discharge berange at the mouth gage on April 22 was came zero and changed to ebb at 1420
5.61 feet and on March 17, 4.16 feet, at both Mouth and Mid gages, but both
but on the latter date the maximum el- had experienced maximum water elevaevation reached was 1.4 feet higher than tion at 1330. This is an example of
on April 22. As a result, the maximum how discharge reversal lags reversal in
discharge on March 17 was nearly twice slope. At both locations the stage had
that of April 22 as can be seen on fig. 5. been falling for 50 minutes before the
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Leopold, Collins & Collins
478
discharge reversed from flood to ebb direction.
The time relation among the parameters slack water, gage height, and slope
is somewhat unexpected. Velocity does
not become zero when the water surface
elevation changes from rising to falling
or vice versa. Velocity continues for onehalf to one hour after gage height has
reached its maximum or minimum and
has reversed. This is shown in fig. 6
which shows the time relation of slack
water to minimum water surface elevat ion.
On April 22 at Mouth gage, the minimum gage height occurred at 1348 hours
and reversed, but the velocity did not
become zero until 1430. On the same
day the most upstream gage, Head,
reached minimum gage height at 1700
hours, but velocity did not become zero
until 1742. On March 17, at Mouth gage
maximum gage height was at 1324, but
velocity became zero at 1448.
The reason for this lag is apparently
related to the inertia of the flowing water.
Water flowing upstream during
flood flow keeps moving upstream until after the slope has reversed and the
adverse gradient brings the velocity to
zero.
In the present study, the water surface
elevation was measured with sufficient
precision that water surface slope may
be computed between pairs of stations
through a portion of the tidal cycle. The
elevation differences are small, but they
are generally larger than the precision
of the leveling. These differences range
between 0.10 and 0.45 feet and the distance between stations are mostly in the
order of 1,200 feet so slopes are in the
magnitude of 1 x
to 40 x
Fig. 7 is a plot of water surface slope
computed between adjacent gages as a
function of times for April 22, 1984 observations. The slope values for the
two dates are similar in that the middle reach of the three mile-long channel
is steeper than either the upstream or
downstream reach. In figures 8 and 9,
the water surface is plotted as profiles.
On April 22 the water surface was
falling, but sloped mouthward more or
less uniformly from 0800 to 1000 hours
a t which time the midreach steepened
and the most mouthward 3,000 feet was
very nearly level. This steepening resulted from the fact at the Head and E
stations the rate of water surface fall was
much less than a t the stations nearer the
mouth. Between 1400 and 1600 hours
the water was rising near the mouth
but continuing to fall upstream of Station D, but in the next hour all stations
except Head were rising and slope was
headward through all reaches. At 1600
hours the profile is V shaped, in that
the mouthward half of the channel had a
slope headward while the headward half
had a slope mouthward.
5
Hydraulic resistance
In most computations of tidal flow it is
necessary to use a measure of flow resistance or hydraulic roughness. Without
direct measurements of hydraulic gradient (water surface slope), the roughness
must be estimated. In the present study
the parameters necessary for computing
roughness, depth, slope, and velocity,
were measured in the field. Computed
values of roughness from these measurements also give a t least some indication why the central reach of the channel
has a consistently steeper water surface
slope than either the upper or the lower
end.
Slope measurements are available for
C A T E N A - - A II I n t e r d i 9 c ip Ii n nr y J o u r n a I o f S 0 I L S C I E N C E - - H Y D R 0 L 0 G Y -G
E 0 M 0 R P H 0 L 0G Y
479
Hydrology of tidal channels, California
.0006
E
0 TO MI0
c
T O 0,
Fig. 7: W a t e r surface slope computed between adjacent gages as a f u n c t i o n of t i m e
during April 2$ 1984 observation period. Slope i s considered positive during ebb
pow,
5 ILL
I900
----
.
0800
0900
IO00
I100
I300
I500
I
D
U
W
I
Fig. 8: Longitudinal profiles of the water surface along the channel of Tule Slough
each hour during the observation period of April A'gJ 1984. T h e stage falls (ebb
tide) and t h e n rises during the period.
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Interdisciplinary J o u r n a l of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G K
Leopold, Collins & Collins
480
7
- - - - - - - - - - - - - - -:-l40o
-
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a
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4
/
/
b.
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a 4
3
67
/
a
/
W
I-
/
a
3
3
0
a
W
-
I
H
Fig. 9: Longitudinal profiles f o r the observation period o n March 17, 1984. The
stage rises (flood tide) and falls during this period.
0900 April 22
Depth along channel
3-4 feet
Resistance Value
1600 March 17
Depth along channel
4-6 feet
Resistance Value
1200 March 17
Depth along channel
6-8 feet
Resistance Value
Manning’s
n
u/u,
Manning’s
n
Manning’s
n
u fu,
,046
.028
,032
,033
,050
.062
,032
4.9
11.7
9.8
9.9
6.4
5.1
9.1
,055
,042
,039
,042
,062
-048
,051
,034
,038
.036
.029
,036
,063
,044
11.0
Station
Mouth
A
C
D
Mid
E
Head
u/u,
6.5
8.5
8.6
8.4
5.6
7.2
6.5
9.8
9.9
12.3
9.9
5.6
7.6
Tab. 1: Hydraulic resistance a t three chosen t i m e s .
C A T E N A-A
n I n t e r d i II c ip I i II & c y J o u rn a I
Df
S 0 I L S C I E N C E- HY D R O L 0 G Y -G
EO M 0 RP H 0 L 0 G Y
.
-
48 1
Hydrology of tidal channels, California
the full measurement period on each
of the days when several stations were
manned.
However, hydraulic theory
specifies that computation of resistance,
either Manning n or the ratio u/u,,
applies only in steady, uniform flow.
Therefore, t o sample resistance values
along the length of the channel, three
times were chosen which appear to satisfy the requirement. At 0900 hours
April 22, when the flow was ebb, the water surface profile was neither extremely
broken nor flat as it would be at maximum tide. Depths along the channel
from mouth t o head at this time were
from three to four feet. Distances used
for computation of slope were from midpoints between gage locations.
Another example is 1600 March 17
when the flow was ebb, the depths along
the channel were from four to six feet.
The third example is 1200 March 17
when the flow was in flood, the depths
were from six to eight feet. Tab. 1
shows the hydraulic resistance expressed
as Mannings n and u/u,, for each station
along the length of Tule Slough.
These values confirm the interpretation of the water surface profiles in that
the steep slope in the middle reach of
channel is caused in part by higher values for resistance. The roughness values are scattered and not very consistent, but it appears that the steep slope
in the reach from Stations E to Mid is
related to high roughness, high values of
n and low values of u/u,.
The computed values of roughness reflect all the types of resistance, bank
as well as bed irregularities and channel alignment. We believe that the major part of the resistance comes from
bed irregularities. As previously noted,
the bed protuberance in the mouthward reach had an average amplitude
CATENA-An
of 1.3 feet. Using an often-observed
depth of six feet, the relative roughness,
(depth/roughness height) is 4.5 which
would be typical for a channel of moderate roughness.
Roughness at each station was greatest for intermediate stage (4-6 ft.). This
range of elevation generally corresponds
to the vegetated surfaces of the slump
blocks. More d a t a are needed to ascertain if this observation is repeated in
other examples.
6
Hydraulic geometry
An attempt to describe the relations
among width, depth, velocity, and discharge in a tidal channel has previously
been made only by Myrick & Leopold
(1963) in a Potomac estuary marsh.
This is more complicated than in rivers
because discharge and velocity become
zero both at large depth (flood reversing to ebb) and at low depth (ebb reversing t o flood). Myrick and Leopold
concluded (p. B15) that “the principal
difference in the at-a-station hydraulic
characteritics of estuarine and terrestrial
streams is that the former have a much
more rapidly changing velocity with discharge than do terrestrial rivers. This is
compensated by a less rapidly changing
depth and width with discharge.”
The
same
general
conclusion
is reached from the present study except
that the difference between the estuarine
and terrestrial channel is not as marked
as found in the Potomac estuary study.
Fig. 10 presents plots of width, depth,
and velocity vs. discharge for the Mouth
location. Our present data appear more
scattered or less consistent than the similar data of Myrick and Loepold for reasons that can be only conjectured. The
velocities of the present study are all
I n t e r d i s c i p l i n a r y Journal of SOIL S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
482
Leopold, Collins & Collins
x EBB
APRIL 22
MARCH 17
o FLOOD
I
&
'
O
+
EBB
*
FLOOD
'1
H
Fig. 10: Hydraulic geometry
relations at M o u t h gage: m e a n
I
.I
I
I O
I
I
I I l l
IO0
I 000
ted
us.
discharge.
DISCHARGE CFS
measurements by float, multiplied by 0.8
to approximate mean velocity for the
cross section. The Potomac study measured velocity by current meter. The
cross sections in Tule Slough are less uniform than those of the Potomac study
owing to the prevalence of slump blocks
that fall irregularly into the channel. An
advantage of the present study is that for
each of the two days of intensive observation, all seven sections were measured
simultaneously and by the same methods. In our 1988 data, four sections were
measured simultaneously.
The value of exponents in the hyCATENA-An
draulic geometry at-a-station is tabulated here, w a: Q6, d a: Q f , v aQm:
b
f
'hle Slough
Mouth gage
. l l .35
.ll .35
E gage
Head gage
.17 .40
Wrecked Recorder Slough'
.04 .18
Old Mill Creek'
.OB
.14
Ravenswood Slough'
.14 .OB
Terrestrial rivers, average2
.26
.40
From Myrick & Leopold (1963).
Leopold, Wolman & Miller (1964).
m
.55
.55
.25
.78
.78
.78
.34
As in rivers, width increases downstream
faster than depth, so width/ depth ratio increases downstream. As mentioned
earlier, bed elevation intersects the level
l n t c r d i n c i p l i n a r y J o u r n a l of S O I L S C I E N C E - H Y
DROLOGY--GEOMORPHOLOGY
Hydrology of tidal channels, California
483
of MLLW near Mid gage, so at low
flow, reaches upstream continue to drain
through the whole ebb tide and become
dry when water level falls to or below MLLW. Upstream of the intersection, channels are narrow, deep, and Ushaped. In the downstream reaches the
channels are more triangular or rounded
in shape. The meaning of these shape
relations to tide level cannot be ascertained from the few examples studied
but appear to be distinctive enough to
warrant further study.
In Wrecked Recorder Slough the highest values of discharge, considered to be
the effective discharge, tended t o occur
at bankfull, for the channel was regularly overtopped at high tide. Not so in
Tule Slough, where bankfull is equalled
or exceeded in only one of three high
tides. The effective discharge is believed
to be within banks, but at this time
we are unsure how effective discharge
should be defined in Tule Slough.
measurements of suspended load and velocity were made at locations C, Head,
T T W , CAN and RR during a six hour
period of flood tide. The headward stations were dry during the first part of
the tidal cycle and measurements began
when water reached each measurement
point. Fig. 2 shows that the mean bed
elevation at MLLW is near station E or
about 7,000 feet from the mouth. Therefore, on the average, all of the channel
upstream of that point is drained of water during ebb tide.
Suspended load was measured at intervals of 5 to 15 minutes at five locations using a D64 sampler while at
the same time water surface elevation
was recorded and velocity was measured
by surface floats. The data are plotted
in fig. 11. Sediment concentration increases markedly with discharge at most
stations, but there are unexplained deviations from this simple relation. There is
a definite progression of decreasing values of maximum sediment concentration
from the large downstream channel sections to the smaller upstream stations.
The peak concentrations of 200 mg/l at
section C is ten times larger than the
maximum concentration at the uppermost location RR.
The temporal variability in sediment
concentration at station C reflects the
turbulent flow there. Rising and falling
clouds of sediment were visible passing
through the downstream section as samples were taken, especially during the
period of high velocity. The variability
at T T W , a tributary confluent t o Tule
Slough near station C, also reflects this
turbulent vertical mixing in the main
channel, because flow at TTW was not
turbulent. In general, turbulence decreased with distance upstream.
The sediment concentration is not di-
7
Suspended sediment
concentrat ion
Observation in the field demonstrates
that the water is more clear - less turbid - in upstream reaches of the tidal
channels than near the mouth. Quantitative data were needed to determine
how large are the differences and what
controls them.
In part to obtain suspended sediment
samples over a wide range of channel
size, two additional observation locations were established on the headward
portion of the main Tule channel, and
one on a tributary. These are called, respectively, Railroad (RR), (CAN), and
Tule Tributary West (TTW).
On September 7, 1988, simultaneous
CATENA-An
Interdisciplinary Journal of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Leopold, Collins & Collins
484
J
2
200
s
z
2
I-
a
a
I-
z
I50
W
0
z
0
0
I-
z
W
zn
IO0
W
0
n
W
n
z
W
50
a
(I)
3
(0
,/.',
0
-.
\
I-
>
-.5
-
+---
0
J
W
7
I
Q . , ,
'4'
/'-.
i
--i
/ - - A
.
e A
t
0
I
-.e.--\_
(I)
LI.
L//
I
1
0
W
RR
-I
-
I
I
I
I100
I200
I300
I
I400
I
I500
I
I-
I600
HOUR
Fig. 11: Suspended sediment concentration as a function of time during flood tide
at five stations on September 7, 1988. Below are plotted curves of mean velocity
during the same observation period.
rectly related to velocity of flow, as can
be seen by the data for station C in
fig. 11. Similarly, at the headwater
station RR, the maximum velocity occurred at 1435, but concentration continued to increase until 1610. Nor does
it correlate with water surface slope.
Concentration most closely follows discharge, which is more dependent on
stage (cross sectional area of flowing wa-
CATENA-An
ter) than on either slope or velocity.
These observations pose interesting
questions about both source and disposition of sediments, and about processes of marsh history. The most obvious areas of sediment accumulation that
could be the source of suspended load
in Tule Slough are the broad mud flats
bordering many shorelines of San b a n cisco Bay. Much of the material in these
Interdisciplinary J o u r n a l of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Hydrology of tidal channels, California
485
mud flats was derived from hydraulic in any short period of years.
mining of river valleys near the end of
the 19th century. To provide passage A c k n o w l e d g e m e n t s
of barge traffic, the outlet of Petaluma
River is extensively dredged through the Several colleagues and students manned
mud flats of the north border of San the staff gages to read gage heights and
measure velocities over long hours. Dr.
Pablo Bay.
The time of high tide at section C Kirk Vincent was most helpful both in
was about 1358 and low tides at 0753 instrumentation and in making observaand at 2004. Section C experienced tions.
Dr. W.W. Emmett, of the U.S. Geoa gradual increase in mean velocity to
logical
Survey, provided many forms of
about 1130, from which time it remained
assistance,
including the analysis of susnearly steady at 0.9 feet per second for
pended
load
samples in the laboratory.
2 1/2 hours. Sediment concentration reDr.
Kent
G. Dedrick arranged for a
mained low until about the time veloclevelling
survey
by the California State
ity reached 0.9 ft/sec and then rapidly
Lands
Commission
to connect our level
increased from 40 to 200 mg/l. Concennetwork
to
the
NOAA
gage at Lakeville.
tration peaked at 1315, probably coinThis
was
an
important
contribution to
ciding with maximum flood discharge.
the study.
We conjecture that sediment is not entrained in quantity until some volume of
discharge is reached and thereafter tends References
t o follow the discharge curve. At upCOLLINS, L.M., C O L L I N S , J.N. &
LEOPOLD, L.B. (1987): Geomorphic
stream locations both the discharge and
processes of an estuarine marsh: Preliminary
sediment concentrations are lower. Beresults and hypotheses. Internat. Geomorcause these upstream channels are withphology 1986, Part I. John Wiley & Sons
out water during part of the ebb cycle,
Ltd., 1049-1071.
they are progressively filled during the
L E O P O L D , L.B., W O L M A N , M . G . &
MILLER, J.P. ( 1 9 6 4 ) : Fluvial Processes
flood cycle. This filling must be by wain Geomorpholigy. W . Freeman Co., San
ter of relatively high velocity, or surface
Francisco.
water. Perhaps this skimming of surface
M Y R I C K , R.M. & L E O P O L D , L.B.
water leaves behind the water near the
(1963): Hydraulic geometry of a small tidal
bed where concentrations are highest.
estuary. U.S. Geological Survey Prof. Paper
4 2 2 B , 18 pp.
This skimming does not mean that
the sediment is deposited. It may reR E E D , D . J . (1987): Temporal sampling
and discharge asymmetry in salt marsh
main in suspension and be carried with
creeks. Estuarine, Coastal and Shelf Sciences
the water in ebb flow. It is observed
25, 459-466.
that the channel configuration remains
S T E V E N S O N , R.E. & E M E R Y , K.O.
amazingly constant for decades. Only
(1958): Marshlands at Newport Bay, Calthe occasional tide is overbank, and such
ifornia. Allan Hancock Foundation Occasional Paper No. 20.
tides contribute to the natural levee seen
bordering the channel in downstream
reaches. But on the whole, the suspended load is washed upstream and
downstream with very little deposition
CATENA-An
I n t e r d i s c i p l i n a r y Journal of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Leopold, Collins & Collins
486
Explanation of tables in Appendices
Elevation:
Velocity:
Width:
Area:
Depth:
Discharge:
Slope:
Observed gage heights adjusted to datum of MLLW a t Lakeville
tide gage near mouth of Tule Slough.
Mean velocity is float velocity observed multiplied by 0.8 to
approximate mean for section.
Water surface width excluding shallow water overflowing slump
blocks at high stage.
Planimetered cross sectional area of flowing water excluding
overflow as in width described.
Area defined above divided by width as defined above.
Product of area defined above and mean velocity as defined above.
For a given station computed as water surface elevation difference
between the station upstream and the one downstream divided by
distance along channel between those gages.
Positive values refer to ebb tide. Negative values refer to flood tide.
Throughout this paper MHW is the arithmetic mean elevation of all high tides,
two per lunar day, for the tidal epoch ending in 1978. MHHW is the arithmetic
elevation of the highest of the two tides in a day. MLLW is the mean of the lower
of two tides in each day. All elevations are referred to the datum of MLLW at the
NOAA tide gage at Lakeville, California (gage no. 9415423), which is the near the
mouth of Tule Slough.
The d a t a in these appendices have been tabulated for intervals of one half hour
though the original d a t a include observations made at intervals of a few minutes
and thus show many details. But for general purposes the uniform time intervals
give an uncluttered sense of relationship. For some purposes those details may be
important and are on file.
From
To
Petalunia River
Mouth
Mouth
A
C
D
Mid
E
Head
A
C
D
Mid
E
Head
Railroad
Distance
(ft)
800
1240
1390
1155
1165
1970
6405
4882
C Distance
(ft)
800
2040
3430
4585
5750
7720
14125
19007
Appendix 1: Distance between gages, Petalurna M a r s h along centerline of channel,
feet.
CATENA-An
I n t e r d i s c i p l i n a r y J o u r n a l of SOIL S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Hydrology of tidal channels, California
Hour
0530
0600
0630
0700
0730
0800
0830
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
Elevation
above
MLLW ( f t )
Velocity
Width
V
W
(ft/wc)
(ft)
5.25
5.15
4.93
4.58
4.04
3.49
2.91
2.37
1.88
1.50
1.16
0.81
0.54
0.00
0.24
0.4G
0.64
0.49
0.51
0.56
0.42
0.53
0.45
0.44
0.42
0.34
0.24
0.20
0.36
0.24
0.18
0.00
-0.18
-0.33
-0.43
-0.52
-0.64
-0.56
-0.56
-0.53
-0.49
47
47
47
47
47
46
46
45
43
42
41
39
38
36
35
34
34
34
34
35
39
42
44
46
46
46
47
47
0.26
-0.02
-0.20
-0.36
-0.36
-0.70
0.12
0.67
1.35
2.03
2.69
3.32
3.90
4.37
4.65
487
Area
A
(ft2)
Depth
d
(ft)
336
333
322
304
280
254
227
205
181
7.1
7.1
6.8
6.5
6.0
5.5
5.0
4.6
4.2
3.8
3.7
3.5
3.3
3.2
3.0
3.0
2.8
2.8
3.0
3.1
3.4
3.8
4.3
4.7
5.3
5.9
6.3
166
151
137
1ZG
117
106
101
94
94
101
111
131
158
188
216
246
273
294
308
6.6
Discharge
Q
Slope
5
(ft3/s)
XIOs
0
80
148
195
137
130
127
86
96
75
66
58
43
28
21
36
23
17
0
-20
-39
-68
-98
-138
-138
-153
-156
-151
4.0
3.2
4.0
5.6
4.8
4.8
3.2
-0.80
2.4
1.6
4.8
4.8
2.4
2.4
1.4
-1.G
0
0.8
-2.4
-0.8
1.6
-2.4
-3.2
Appendix 2: Mouth gage, Petalurna Marsh, April 22, 1984. Slope: Mouth to A .
Hour
0800
0830
0900
0930
1000
Elevatioii
above
MLLW ( f t )
Velocity
Width
V
W
(ft/sec)
(ft)
3.54
2.95
2.42
1.95
1.56
1.06
1.09
1.06
0.92
0.77
0.74
0.64
0.64
0.56
0.52
0.50
0.40
0.30
0.08
-0.10
-0.41
-0.56
-0.66
-0.62
-0.74
-0.8G
-0.84
-0.79
26
26
26
26
24
22
21
21
20
20
19
19
19
19
20
21
23
1030
1.22
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
0.85
0.53
0.29
0.04
-0.14
-0.30
-0.33
-0.17
-0.14
0.65
1.35
2.04
2.66
3.31
3.88
4.34
4.69
2G
26
26
26
26
2G
Area
A
(ft’)
Depth
Discharge
d
Q
Slope
5
(ft)
(ft3/s)
x105
143
128
115
101
92
5.5
4.9
4.4
3.9
3.8
152
140
122
93
71
85
3.8
63
77
70
66
60
57
54
53
57
63
73
87
103
120
137
152
164
172
3.6
3.4
3.3
3.1
3.0
2.8
2.7
2.9
3.2
3.5
3.8
4.0
4.6
5.3
5.8
6.3
6.6
49
45
37
31
29
22
16
5
6.5
5.7
5.7
5.3
3.8
3.4
1.9
1.5
1.2
1.1
2.3
2.3
0.4
1.2
-0.4
-2.7
-2.2
-2.2
-2.7
-3.4
-1.1
-1.2
-2.7
-G
-30
-49
-68
-74
-101
-131
-138
-136
Appendix 3: A gage, Petaluma Marsh, April 22, 1984. Slope: Mouth to C.
Leopold, Collins & Collins
488
Hour
0800
0830
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
Elevation
above
MLLW ( f t )
Velocity
Width
V
W
Depth
Discharge
d
Q
Slope
5
(tt)
Area
A
(ft2)
(ft/sec)
3.66
3.06
2.52
2.02
1.60
1.25
0.86
0.57
0.28
0.05
-0.14
-0.30
-0.35
-0.19
0.13
0.60
1.29
1.98
2.62
3.23
3.85
4.35
4.66
0.82
0.84
0.92
1.18
0.75
0.76
0.87
0.84
0.78
0.68
0.54
0.56
0.44
0.20
0.0
-0.28
-0.58
-0.58
-0.74
-0.82
-0.90
-0.84
-0.64
(ft)
(ft3/s)
x105
40
39
36
35
34
32
30
29
27
26
25
24
24
25
27
29
32
34
37
39
40
40
40
153
129
104
92
77
62
58
47
36
26
26
22
19
24
33
46
67
90
113
135
160
181
192
3.8
3.3
3.0
2.6
2.3
2.1
1.8
1.6
1.3
1.1
1.0
0.9
0.8
1.0
1.2
1.6
2.1
2.6
3.0
3.5
4.0
4.5
4.8
126
108
96
108
58
49
46
38
29
21
14
12
8
5
0
-12
-39
-53
-84
-111
-145
-152
-123
9.2
7.7
8.4
9.4
10.8
13.9
12.1
12.9
14.7
17.3
16.9
7.4
-0.4
-4.9
-6.1
-3.9
-2.3
-4.7
-9.8
0.4
-1.6
Appendix 4: C gage, Petaluma Marsh, April 22, 1984. Slope: A to D.
Hour
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
Elevation
above
MLLW ( f t )
Velocity
Width
Discharge
W
Area
A
Depth
V
d
Q
Slope
5
(ft/sec)
(ft)
(rt2)
(ft)
(rt3/s)
x105
2.G5
1.19
0.92
0.82
0.76
0.68
0.55
0.68
0.52
0.48
0.45
0.26
0.26
0.00
-0.10
-0.40
-0.76
-0.80
-0.72
-0.78
-0.79
-0.67
28
27
26
25
24
23
22
21
20
20
20
20
20
22
24
27
28
28
28
28
28
93
79
70
61
63
47
40
35
32
30
28
27
31
39
55
73
92
107
121
140
149
3.4
2.9
2.6
2.5
2.3
2.1
1.8
1.7
1.6
1.5
1.4
1.4
1.5
1.8
2.3
2.8
3.3
3.8
4.3
5.0
5.3
111
73
57
46
36
26
27
18
15
14
7
7
0
- 4
-22
-55
-74
-77
-94
-111
-100
13.3
16.8
19.4
19.4
24.2
29.3
37.0
40.5
46.1
49.5
50.0
40.4
39.3
-3.1
-9.1
-6.1
-5.6
-6.9
-10.0
-4.7
-1.8
2.14
1.76
1.44
1.10
0.88
0.56
0.34
0.20
0.10
0.04
-0.02
0.13
0.53
1.20
1.95
2.60
3.19
3.65
4.33
4.65
L
Appendix 5: D gage, Petaluma Marsh, April 22, 1984. Slope: C to Mid.
CATENA-An
I n t e r d i s c i p l i a s i - y J o u r n a l of S O I L S C I E N C E - - H Y D R O L O G Y - G E O M O R P H O L O G Y
489
Hydrology of tidal channels, California
Hour
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
Elevation
above
MLLW ( f t )
Velocity
Width
V
W
(ft/sec)
(ft)
2.83
2.41
2.05
1.70
1.42
1.25
1.09
0.99
0.93
0.85
0.81
0.74
0.70
0.69
1.08
1.84
2.49
3.07
3.68
4.24
4.62
0.84
0.80
0.79
0.66
0.GO
0.48
0.42
0.28
0.24
0.16
0.21
0.23
0.20
0.12
-0.36
-0.80
-1.00
-1.12
-1.34
-1.10
-0.76
37
35
34
33
32
31
30
29
29
28
28
28
28
28
30
34
36
38
39
43
44
Area
A
Q
Slope
5
(ft3/s)
x105
102
86
73
53
43
32
26
17
13
9
11
12
10
6
-22
-70
109
-144
-205
-194
-143
16.6
18.5
19.8
21.3
25.5
27.9
24.7
40.9
43.8
45.7
46.0
46.8
38.7
20.3
-6.2
-14.5
-17.7
-14.8
-8.4
Discharge
(ft2)
Depth
d
(ft)
121
107
93
81
72
66
62
59
56
55
53
52
51
51
62
87
109
129
153
176
191
3.2
3.0
2.7
2.4
2.2
2.1
2.0
2.0
1.9
1.9
1.9
1.8
1.8
1.8
2.0
2.5
3.0
3.4
3.9
4.4
4.7
-
-10.0
-4.9
Appendix 6 : Mid gage, Petaluma Marsh, April 22, 1984. Slope: D to E.
Hour
0800
0830
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1900
Elevation
above
MLLW ( f t )
3.98
3.53
3.18
2.68
2.34
2.10
1.88
1.72
1.56
1.50
1.42
1.38
1.32
1.28
1.26
1.22
1.18
1.44
2.00
2.74
3.40
4.00
4.48
Vclocity
Width
V
W
Area
A
(ft/sec)
(ft)
(rt2)
0.30
0.GG
0.08
0.68
0.68
0.68
0.60
0.59
0.60
0.57
0.42
0.34
0.29
0.33
0.40
0.30
0.20
-0.04
-0.90
-1.22
-1.20
-1.08
-0.94
36
35
34
32
31
30
30
29
28
28
28
28
27
27
27
27
27
28
30
33
34
36
36
133
117
106
89
78
72
65
GO
55
53
52
50
48
47
47
45
44
52
68
92
Depth
d
(ft)
Disrhargr
Q
Slope
5
3.7
3.4
3.1
2.8
2.5
2.3
2.2
2.0
1.9
1.9
1.8
1.8
1.8
1.7
1.7
1.7
1.7
1.9
2.2
2.8
(ft3/s)
40
76
72
61
53
49
39
35
33
30
22
17
14
16
19
14
x105
11
-2
-61
-112
113
3.3
-13G
134
151
3.7
4.2
-145
-142
17.8
13.7
14.7
20.3
23.4
23.9
23.9
25.9
24.9
26.9
25.9
27.4
28.4
26.9
5.1
-20.3
-25.9
-19.3
-14.2
-12.2
-7.1
Appendix 7: E gage, Petaluma Marsh, April 22, 1984. Slope: Mid to E.
CATENA-An
l n t e r d i s c i p l l n a r y J o u r n a l of S O I L S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Hour
Elevation
above
Velocity
Width
Area
W
A
Depth
d
Discharge
V
Q
Slope
5
MLLW (ft)
(ft/sec)
(ft)
(ft2)
(ft)
(ft3/s)
x105
4.20
3.80
3.41
3.07
2.77
2.52
2.32
2.16
2.05
1.96
1.90
1.87
1.84
1.82
1.81
1.80
1.79
1.78
1.78
1.78
2.44
3.55
0.32
0.32
0.43
0.44
0.38
0.42
0.37
0.29
0.30
0.28
0.24
0.21
0.13
0.09
0.09
0.04
0.10
0.08
0.10
0.08
-0.89
-0.78
14
14
14
13
12
11
10
9
9
8
8
8
8
7
7
7
7
7
7
7
10
14
32
26
21
17
13
10
8
6
5
3
3
3
3
2
2
2
2
2
2
2
8
23
2.3
1.9
1.9
1.3
1.0
0.9
0.7
0.6
0.5
0.5
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.9
1.7
10
8
9
7
5
4
3
2
2
3.4
4.2
3.6
6.1
6.7
6.6
6.9
6.9
7.7
7.2
7.5
7.7
8.1
8.4
8.6
8.7
9.5
5.3
-3.4
-15.0
-15.0
-7.0
0800
0830
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
1730
1800
1830
1
1
1
0
0
0
0
0
0
0
0
-7
-18
Appendix 8: Head gage, Petaluma Marsh, April 22, 1984. Slope: E to Head.
Hour
Elevation
above
MLLW ( f t )
Velocity
Width
W
Area
A
Depth
d
Discharge
V
Q
Slope
5
(ft/sec)
(ft)
(ft’)
(ft)
(fts/s)
x105
3.57
4.63
5.36
5.96
6.36
6.61
6.76
6.79
6.72
6.37
5.78
4.98
4.19
3.38
2.63
-0.83
-1.02
-1.14
-0.96
-0.88
-0.60
-0.70
-0.67
-0.32
0.54
1.04
1.29
1.20
1.24
1.08
46
47
47
47
47
47
47
47
47
47
47
47
47
46
45
257
307
343
370
388
402
407
409
406
389
361
324
287
250
213
5.6
213
-313
-391
-355
-341
-241
-285
-274
-130
210
375
418
344
310
230
-2.4
-4.8
-2.4
-2.4
0
-0.8
0.8
1.6
4.8
10.1
15.1
17.3
18.0
10.1
1000
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
1600
1630
1700
6.6
7.3
7.9
8.3
8.5
8.7
8.7
8.6
8.3
7.7
7.0
6.1
5.4
4.7
Appendix 9: Mouth gage, Petaluma Marsh, March 17, 1984. Slope: Mouth to A .
CATENA-An
I n t e r d i s c i p l i n a r y Journal of SOIL S C I E N C E - H Y D R O L O G Y - G E O M O R P H O L O G Y
Hydrology of tidal channels, California
Hour
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1630
lG00
1 ~ 3 0
1700
49 1
Elevatioii
above
MLLW ( f t )
Vrlocity
Width
V
W
Arra
A
(ft/scc)
(ft)
(ft2)
4.GO
5.30
5.93
G.33
G.Gl
6.75
6.80
6.74
G.43
5.88
5.20
4.47
3.G9
2.92
-0.88
-0.80
-0.82
-0.7G
-0.G8
-0.G1
-0.54
-0.36
0.48
1.18
1.45
1.70
1.8G
1.9G
2G
2G
2G
2G
2G
2G
2G
2G
26
2G
2G
2G
2G
1GG
186
2G
201
212
220
225
228
22.5
214
200
182
164
145
124
Depth
d
(ft)
Diacliargt
6.4
7.1
7.7
8.1
8.5
8.G
8.8
8.G
8.2
7.7
7.0
G.3
5.G
4.8
-14G
-148
-1G5
-1G1
-150
-137
-123
-81
Q
(ft3/s)
103
23G
2G4
279
270
243
Slop(,
5
~ 1 0 "
-8.7
-5.7
-4.G
-2.3
-0.7
-0.8
-0.3
1.1
6.3
9.1
G.3
19.8
21.3
13.7
Appendix 10: A gage, Petaluma Marsh, March 17, 1984. Slope: Mouth to C.
Hour
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1630
1G00
1630
1700
Elev;rt,ion
>tl>OVC.
MLLW ( f t . )
Velocity
Width
Area
V
W
A
(ft/scc)
(ft)
(ft')
4.40
6.21
6.84
G.30
G.59
G.74
G.81
G.76
G.51
G.20
5.41
4.71
3.94
3.60
-0.97
-0.89
-0.G4
-0.G2
-0.50
-0.48
40
40
40
40
40
40
40
-0.18
40
0.58
1.28
2.24
1.62
1.88
1.48
40
40
182
214
240
267
270
274
27G
274
2GG
247
23s
197
-0.93
40
40
40
39
1G3
129
Dr1,t.h
<1
(ft,)
Discliary
4.5
-177
-199
-214
-154
-1G7
-137
-132
-49
154
31G
5.3
G.O
G.4
G 7
6.8
G.9
G.9
G.7
G.2
6.6
4.8
4.8
3.2
Q
(ft3/s)
Slop?
5
X105
500
-8.0
-G.3
-4.1
-2.0
-l.G
-8.0
-1.7
0.8
5.5
9.0
18.2
296
30G
191
15.1
22.4
1g.9
Appendix 11: G gage, Petaluma Marsh, March 17, 1984. Slope: A to D.
1
Hour
Elevation
abovc
MLLW ( f t )
6.14
1430
1500
5.64
4.18
3.46
Velocity
Width
Area
V
W
A
(ft/sec)
(ft)
(rt2)
-1.20
-1.30
-1.18
-0.92
-0.82
-0.60
-0.66
-0.68
-0.52
0.25
1.12
1.32
1.68
1.83
2.60
28
28
28
28
28
28
28
118
140
162
185
194
200
203
204
203
200
188
172
157
135
I15
28
28
28
28
28
28
28
28
Q
Slopc
5
(rt3/s)
xio5
Depth
d
(ft)
Discharge
4.2
-142
-182
-191
-170
-169
-120
-134
5.0
5.8
G.G
G.9
7.1
7.2
7.3
7.2
-118
-1OG
-9.9
-10.4
-6.G
-2.0
-1.0
-1.3
-1.3
1.8
7.1
50
6.4
G.7
(3.1
5.6
4.8
4.1
211
227
2G4
247
23G
12.5
17.7
22.4
24.1
36.G
Appendix 12: D gage, Petaluma Marsh, March 17, 1984. Slope: C to Mad.
Leonold. Collins SC Collins
492
Hour
U
Elcvat,ioii
xbovc
MLLW ( r t )
Velocity
Width
V
W
(rt/scc)
4.17
4.97
6.71
G.23
6.53
(3.71
G.78
(3.79
G.G3
6.31
5.82
5.23
4.GO
3.91
-1.29
-1.26
-1.25
-1.00
-0.82
-0.76
-0.70
-0.42
0.18
0.74
0.08
1.08
1.18
1.08
1030
1100
1130
1200
1230
1300
1330
1400
1430
1500
1530
lG00
lG30
1700
Depth
d
(ft)
Dischirrgc
(ft)
Arca
A
(rt2)
40
40
40
40
40
40
40
40
40
40
40
40
40
40
180
203
239
254
267
274
278
278
272
257
237
215
188
1G2
4.4
5.0
5.9
6.3
-232
-25G
-299
-254
-219
-20G
-195
-117
49
190
232
232
222
175
6.6
6.8
6.9
G.9
6.7
6.3
5.8
5.3
4.0
4.0
Q
(rt3js)
Slopc
5
~
1
0
-17.3
-13.9
-9.5
-5.0
-3.2
-2.1
-1.0
-0.7
3.8
10.7
lG.G
21.8
-~
Appendix 13: Mid gage, Petaluma Marsh, March 17, 1984. Slope: D to E.
Hour
Elevxtioii
above
Vclocity
Width
Area
Dcptli
Discliargc
1030
1100
1130
3.84
4.71
5.52
-0.88
-0.99
-0.80
-0.66
-0.54
-0.52
-0.41
-0.2G
0.04
0.86
1.04
1.14
35
128
157
183
3.6
4.3
5.1
-113
-155
-183
-203
-217
G.12
1330
1400
1430
1500
1530
IGOO
G.74
G.76
6.G7
(5.30
(5.00
5.53
227
199
187
5.5
5.2
-226
-227
223
184
207
213
Slol~e
-1G.8
-13.3
-9.6
-5.G
-1.5
2.0
4.1
9.1
15.2
Appendix 14: E gage, Petaluma Marsh, March 17, 1984. Slope: Mad to E.
n
Hour
Discharge
(ft2)
Depth
d
(ft)
56
60
65
66
67
67
66
62
56
52
4.0
4.2
4.6
4.7
4.8
4.8
4.7
4.4
4.0
3.7
-28
-20
-18
-20
-20
-19
5
22
28
34
Elevatioii
above
MLLW ( f t )
Velocit,y
Width
V
W
Area
A
(ft/mc)
(ft)
5.90
G.31
6.53
6.62
6.67
6.69
6.60
6.38
5.98
5.48
-0.50
-0.34
-0.28
-0.31
-0.30
-0.29
0.10
0.45
0.62
14
14
14
14
14
14
14
14
14
14
1200
1230
1300
1330
1400
1430
1500
1530
I600
1630
0.83
Q
(ft3/s)
Slope
5
X10’
-3.4
-2.5
-2.0
-1.9
-1.4
0.3
3.3
5.9
7.0
Appendix 15: Head gage, Petaluma Marsh, March 17, 1984. Slope: E t o Head.
CATENA
A
II
I l i t e l r l i s c i p II I I
bi
y .I,,
111 11d l
, , t RC) I L S C I E N C E ~- H Y D R O L O G Y -- C EO&! 0 R . P H O L 0 G Y
~
Hydrology of tidal channels, California
493
____
Hoiir
Elevetioii
;rl,ov(*
MLLW ( f t . )
V(.locit.y
Width
V
W
(ft/sec)
(ft)
0.89
1.G9
2.G8
-0.11
-0.48
-1.07
-1.20
-1.17
-1.08
30
34
37
1030
1100
1130
1200
1230
1300
3.8G
4.G4
5.30
5.77
(7.16
G.32
G.34
G.21
1330
14 00
1430
1600
1630
40
40
40
40
40
40
40
40
-1.13
-0.78
-0.68
-0.15
0 .4 0
+
Arc~a
A
(ft2)
Deptli
(1
(ft,)
66
80
114
1G0
192
218
237
262
1.8
2.4
3.1
4.0
4.8
6.4
Discliary
Q
( f t,3 / s )
-G
-38
-121
-192
-224
-236
-2G7
-19G
-160
6.9
G.3
G.6
G.G
25D
260
266
-38
6.4
+lo2
Appendix 16: Channel data, C gage, September 7, 1988.
Hour
Elc-vat,ioii
ii 1 )ove
MLLW ( f t )
Vclocity
Width
V
W
(ft/s<.c)
(ft)
4.03
5.11
5.67
(3.07
0.20
-0.93
-0.79
-0.G2
-0.46
-0.27
(3.23
-0.14
14
14
14
14
14
14
1300
1330
1400
1430
1500
1630
' Flow revcwnl dowiistremi
Arra
A
(ft2)
Dcptli
d
(ft)
Discliargv
32
2.3
3.4
3.8
4.3
4.5
4.5
47
64
GO
G3
G3
Slo~)c
5
S1o1)c
5
(ft,3/s)
X10"
X10"
-30
-11.9
-37
-0.2
-6.4
C to
R.iiilroad
-2.3
-5.G
-1.4
-3.2
Q
-33
-27
-17
-9
a t C page.
Appendix 17: Channel d a t a , Head gage, September 7, 1988. Slope: C t o Head.
Hour
1430
1600
1530
lG00
Elrvatioir
abovr
MLLW ( f t )
Vclocity
Widt Ii
Area
W
A
6.44
5.83
(ft,/sec)
(ft,)
-0.52
4
-0.37
-0.30
-0.20
G
(3.05
G.ll
* Flow rrvrrsel dowustrciriu
7
7
Dcptli
DiscliarKt.
(ft,')
(ft,)
(ft,3/s)
2.96
6.39
7.75
8.00
0.73
-1.63
-1.99
-2.32
0.90
1.10
1.27
Slop(.
~ 1 0 "
-12.9
-7.G
-3.7
-1.78
;it H e i r d girgc.
Appendix 18: Channel data, RR gage, September 7, 1988. Slope: Head t o RE.
A d d r e s s e s of authors:
Dr. Luna B. L e o p o l d
Department of Geology and Geophysics
University of California Berkeley, CA, U.S.A.
Dr. Joshua N. Collins
Department of Geography
University of California
Berkeley, CA, U.S.A.
C A T E N A-
A I I I n t e r d i s ci p I i ita L y .I ,.I
II I I I d
I o f S 0 I L B C: I E N
Laurel M. Collins
Lawrence Berkeley Laboratory
Berkeley, CA, U.S.A.
I:E-
H Y D R O L 0 G Y - G E O M 0R P H 0 L 0 C: Y