Culvert Scour Assessment
Deadwood Creek Tributary North
Site Information
Site Location:
Coast Range, S Willamette Valley, Deadwood Road
Year Installed:
2000
Lat/Long:
123°40”54.12”W
Watershed Area (mi2): 0.43
44°13’21.62”N
Stream Slope (ft/ft)1: 0.0618
Channel Type:
Step-pool
Bankfull Width (ft): 16
Survey Date:
March 6, 2007
1
Water surface slope extending up to 20 channel widths up and downstream of crossing.
Culvert Information
Culvert Type:
open-bottom arch
Culvert Material: Annular CMP
Culvert Width:
8 ft
Outlet Type:
Mitered
Culvert Length:
56 ft
Inlet Type:
Mitered
Pipe Slope (structure slope): 0.066
Culvert Bed Slope: 0.063
(First hydraulic control upstream of inlet to first hydraulic control downstream of outlet.)
Culvert width as a percentage of bankfull width: 0.51
Alignment Conditions: Culvert aligned to minimize length under road, thus creating greater slope and
necessitating riprap deflector on right bank at inlet and also requiring a riprap step downstream of outlet
to control grade.
Bed Conditions: Large material (larger than natural channel) placed in culvert during construction.
Large rock step present at inlet.
Pipe Condition: Good condition.
Hydrology
Discharge (cfs) for indicated recurrence interval
25% 2-yr
2-year
Qbf2
5-year
10-year
50-year
100-year
10
40
40
58
70
99
111
Bankfull flow estimated by matching modeled water surface elevations to field-identified bankfull
elevations.
2
A—70
Deadwood Creek Tributary North
Site Evaluations
Points represent survey points
Figure 1—Plan view map.
Deadwood Creek Tributary North
A—71
Culvert Scour Assessment
History
The Deadwood Tributary North culvert was
installed in August 2000. Material was placed
and “packed” in the culvert using an excavator.
The material was 8-inch minus, well-graded, and
consisted of a full range of sizes. No significant
material sorting or bedform construction was
conducted, except for the creation of a minor (3 to
4 inch) thalweg.
The preexisting alignment was considered
“stable” with a short culvert. Realignment with the
upstream channel to remove the sharp bend at
the inlet was considered but the structure would
have been steeper and about 120 feet long.
The designers chose to avoid lengthening the
structure and placed a riprap reflector against
the inlet bank to dissipate energy and reflect flow
towards the inlet.
The crossing was located at a grade break
and had a deep scour pool at the outlet. The
channel traveled over root wads dropping 2 to
3 feet in one spot. The designers smoothed the
downstream long profile to remove the large
drop and placed some 12-inch +/- boulders
downstream to improve fish pathway into the
culvert.
Since construction, the inlet riprap has been
damaged (undermined?) and has failed into the
inlet area disrupting and concentrating flow. The
downstream channel was not well defined after
construction and is believed to create potential
fish passage issues.
Maintenance at the site includes foot kicking
and hand rolling of material into the downstream
channel in an effort to improve channel conditions
for fish by concentrating flow and creating a
A—72
deeper thalweg. There has been minor foot
adjustment of material inside the culvert for the
same purpose. Small pieces of debris have been
removed from the inlet.
The above information furnished by
Kim Johansen, USFS.
The flood history at a nearby gauge with a
drainage area of 5.7 square miles (USGS
#14306340) indicates that the largest event
since construction was an approximately 2-year
recurrence interval event in 2006.
Site Description
The Deadwood Tributary (north) culvert is a
bottomless arch that is mitered to conform to
the road fill. The culvert has exposed concrete
footings. The culvert is out of line with the
natural channel alignment judging from the
valley alignment. Just upstream of the inlet to
the culvert, the channel takes a sharp turn to the
left, an artifact of the construction of the road and
stream crossing. Riprap was placed along the
bank here to protect the bank from erosion and to
deflect flow into the culvert. Some of this material
has failed and has entered the culvert inlet
contributing to a large rock step near the inlet
(Kim Johansen, USFS, personal communication).
After the large rock step at the inlet, the channel
drops into a riffle that runs the rest of the length
of the culvert. The entirety of the stream through
the culvert is made up of highly angular oversized
material with a slight fining towards the outlet.
Rock steps in the culvert are bigger and more
frequent than those found in the reference
channel.
Deadwood Creek Tributary North
Site Evaluations
The upstream representative channel consisted
of a high-gradient step-pool channel with a low
active flood-plain surface. The channel sits in a
fairly confined and narrow valley but the floodplain valley width is approximately 2 to 3 channel
widths. Evenly graded riffles were interspersed
by four steps and plunge pools. Thick vegetation
(salmonberry) was encroaching on the channel
adding roughness and providing cover and
shade.
A single representative cross section and pebble
count were taken downstream of the riprap step
but it was not used in the analysis because of
potential backwater influence from Deadwood
Creek.
Profile Analysis Segment Summary
Downstream of the culvert, there was a steep
riprap step and the ability for fish to pass this
step is unknown but based on visual observation
may be a concern. Below the step, the stream
levels off as it enters the flood plain of Deadwood
Creek. Large quantities of brush from roadside
clearing were present downstream of the
crossing.
The profile analysis resulted in a total of 11
profile segments. The culvert consisted of two
profile segments. The downstream segment
in the culvert was compared to three different
representative profile segments in the upstream
channel. There was no suitable comparison
segment for the upstream segment in the
culvert. The upstream transition segment was
compared to two representative profile segments
in the upstream channel. There was no suitable
comparison segment for the downstream
transition segment. See figure 2 and table 1.
Survey Summary
Scour Conditions
Eleven cross sections and a longitudinal profile
were surveyed along Deadwood Tributary North
in March 2007 to characterize the culvert and an
upstream representative reach. No downstream
reference reach was established due to the
proximity of the crossing with the confluence of
Deadwood Creek. In the culvert, reference cross
sections were taken through the riffle, one at the
downstream end of the step and the other in the
downstream third of the culvert. Two additional
cross sections were surveyed downstream of the
culvert to characterize the outlet as well as the
expansion of flow. Another two cross sections
were surveyed upstream to characterize the inlet
as well as the contraction of flow.
Five cross sections were surveyed to characterize
the upstream reach; one at the upstream and
downstream end, one through a step and two
through riffles.
Deadwood Creek Tributary North
Observed conditions
Footing scour – There was no observed scour
undermining footings or threatening structure
integrity.
Culvert bed adjustment – A step (just downstream
of the inlet) has formed from large angular
material sourced from riprap that was placed
on the right bank upstream of the inlet at
construction. There is a scour pool downstream
of the step. This step and scour pool have
developed since construction of the bed. Angular
material is still visible throughout the culvert,
suggesting that much of the originally placed
material has remained in the pipe.
Profile characteristics – The profile has a convex
shape (figure 2). This shape reflects a gradually
steepening profile in the downstream direction.
The structure is not placed in alignment with the
stream valley and instead takes a more direct
A—73
Culvert Scour Assessment
line perpendicular across the roadway straight
to Deadwood Creek. This shortens the channel
length and steepens the profile at the culvert site
and downstream.
Residual depths – The one residual depth in the
culvert is 0.3 feet, which was in the upstream
profile segment that has no comparable
slope segment in the representative channel.
Nevertheless, the 0.3 feet is within the range of
the total population of residual depths from all the
representative channel segments, which ranged
from 0.06 to 1.3 feet (figure 21). This suggests
no significant scour beyond what is found in the
channel outside of the crossing.
Substrate – The culvert has more bed material in
larger size classes than the natural channel. The
natural channel has very few clasts greater than
cobble size, whereas the culvert has material up
to the “medium boulder” size (greater than 512
millimeters). Greater D84 values in the culvert
reflect the greater abundance of large material.
Sorting values are within the range of the natural
channel, but the upstream cross section in the
culvert has a lower skewness value than the
any skewness value in the natural channel.
Pebble counts are provided at the end of the site
summary.
Predicted conditions
Cross-section characteristics – Cross-sectional
flow area, wetted perimeter, and top width are
considerably reduced by the culvert (figure 5,
figure 6, figure 8). Conditions are similar at the
25 percent Q2 (except for top width) but diverge
beginning at the Q2 and higher. The box plots
indicate that flow area, wetted perimeter, top
width, and width-to-depth are much lower in the
culvert when compared to comparable slope
segments in the natural channel. Maximum depth
and hydraulic radius in the culvert are mostly
within the range of that found in comparable
A—74
slope segments. Cross-section characteristics in
the upstream transition do not vary substantially
from comparable slope segments except for
hydraulic radius and maximum depth, which
indicates deeper flow than in the natural channel,
especially at higher flows.
Shear stress – Shear stress appears to increases
in the culvert compared to the upstream channel
(figure 10) and then increases even more just
downstream of the culvert. When compared to
comparable slope segments, the culvert shear
stress values are mostly within the range of
natural channel conditions (figure 19); however,
the maximum value for shear in the culvert is
nearly twice the maximum value found in any of
the comparable slope segments. The upstream
transition segment shear is also within the range
of its comparable slope segments.
Excess shear – The excess shear analysis shows
that the potential for bed mobilization in the
culvert is mostly within the range of that in the
natural channel (figure 20).
Velocity – Although velocity appears to generally
increase within the culvert and just downstream
(figure 11), the culvert velocity is mostly within
the range of velocity of the comparable slope
segments (figure 18), with the exception being
a greater maximum velocity in the culvert than
in the comparable segments. Velocity in the
upstream transition is also mostly within the range
of that found in comparable slope segments,
except with greater maximum velocities in the
transition area.
Scour summary
The culvert shows no significant bed scour.
The only obvious bed adjustment has been the
failure of material into the inlet from bank riprap
upstream of the inlet. This feature has created
Deadwood Creek Tributary North
Site Evaluations
a step near the inlet, but has not compromised
culvert function or capacity to transmit the
modeled flood flows. There was no footing scour
observed during the survey and residual depths
in the culvert are within the range of the natural
channel.
Cross-section characteristics indicate there is
flow constriction created by the culvert, which
is expressed as a reduction in flow width,
area, and wetted perimeter. Velocity and shear
stress appear to increase at the crossing
(and just downstream) (figure 10, figure 11),
but these metrics are not significantly out of
range of channel conditions when compared to
comparable slope segments (figure 18, figure 19).
The only potential exceptions are that maximum
shear and velocity values in the culvert are
greater than those found in comparable slope
segments. The excess shear analysis however,
does not show increased potential for bed
movement because of the larger culvert D84.
This site has been affected by a culvert alignment
that takes a more direct line to Deadwood Creek
than the original stream alignment, resulting in a
steeper grade at the crossing and downstream.
This steep gradient may be the cause of the
higher maximum shear and velocity in the culvert,
yet the culvert bed has similar stability as the
natural channel due to the placement of coarse
material in the culvert during construction.
At the time of the survey, the culvert had likely
only experienced about a 2-year flood event; and
therefore empirical evidence of culvert response
to larger flood flows is not yet available.
It should be noted that the results based on
hydraulic modeling must be tempered by the
steepness of the channel and the associated
potential uncertainty with HEC-RAS modeling at
such a steep site.
Deadwood Creek Tributary North
AOP Conditions
Cross-section complexity – The sum of squared
height differences in the culvert cross sections
are both within the range of those in the channel
cross sections (table 3).
Profile complexity – Vertical sinuosity values in
the culvert segments are low compared to the
natural channel. This reflects the mostly planebed nature of the culvert bed. The upstream and
downstream transition segments have greater
vertical sinuosity and are more within the range
of that found in the channel outside the crossing.
The exception is upstream transition segment E,
which has higher vertical sinuosity than anything
found in the natural channel (table 4).
Depth distribution – There is significantly less
channel margin habitat in the culvert compared to
the channel at the 25-percent Q2 (table 5).
Habitat units – There is similar habitat unit
composition between the culvert and the channel
outside the crossing (table 6). It should be noted
that the culvert is comprised of only one pool, one
riffle, and one step.
Residual depths – The one residual depth in the
culvert is 0.3 feet, which was in the upstream
profile segment that has no comparable
slope segment in the representative channel.
Nevertheless, the 0.3 feet is within the range of
the total population of residual depths from all the
representative channel segments, which ranged
from 0.06 to 1.3 feet (figure 21).
Bed material – As mentioned previously under
scour conditions, the culvert has more bed
material in larger size classes than the natural
channel (up to “medium boulders” in the culvert
compared to “very large cobbles” in the channel).
The culvert also has less fine material, with 4 to
A—75
Culvert Scour Assessment
12 percent less than 2 millimeters in the natural
channel and 1 to 2 percent less than 2 millimeters
in the culvert.
Currently, the steep riprap step downstream of
the outlet may not be passable by upstream
migrating fish.
Large woody debris – There was no LWD present
in the culvert (table 8). The representative
channel had moderate to high LWD abundance.
LWD formed steps and scour pools in the channel
outside the crossing and played a primary role in
habitat unit creation and complexity. Features in
the culvert did not mimic the role of wood in the
natural channel.
Design Considerations
AOP summary
With respect to AOP, conditions in the culvert
appear less suitable than the channel outside the
crossing. Construction of step sequences in the
culvert would be more favorable to fish passage
than the current plane bed that provides little
velocity refuge for migrating fish. No channel
banks were constructed in the culvert and flow
was wall-to-wall during the survey. Concentrating
flow into a more defined thalweg through
construction of channel banks would aid in fish
passage and would provide banks for terrestrial
organism passage. Use of a wider culvert would
have provided more ability to provide these
features. Construction of step sequences would
improve passage in the downstream channel,
where upstream passage is likely currently
blocked by the steep riprap step.
AOP conditions appear less suitable in the culvert
when compared to the natural channel upstream.
Cross-section complexity values are similar, but
thalweg complexity (vertical sinuosity) is less in
the culvert. This matches site observations of a
uniform, plane-bed channel throughout most of
the culvert length (except for the one step near
the inlet). Depth distribution is significantly less
in the culvert, suggesting that shallow margin
habitat needed for fish passage may be limited
in the culvert. Although habitat units and residual
pool depths in the culvert are similar to the natural
channel, the culvert only has one short pool and
one short step and most of the entire pipe is one
long riffle, with wall-to-wall flow and no defined
thalweg. This lack of complexity may impair fish
passage. The presence of boulders in the pipe
may provide velocity refuge for migrating fish;
however, the coarse angular material and a lack
of fines may increase the tendency for subsurface
flow during low-flow periods, which may obstruct
fish passage during the summer.
A—76
The culvert currently has no significant scour
issues. The only bed adjustment (failure of riprap
into inlet) may even have served to increase bed
complexity and passage conditions. The results
indicate that the site should be able to function
similarly to the natural channel with respect to
scour.
At a more fundamental level, placement of the
crossing more in line with the valley alignment
would have avoided steepening of the channel
and would have provided a more suitable (i.e.,
lower) gradient for fish passage.
Deadwood Creek Tributary North
Deadwood Creek Tributary North
350
XS 1:
Pebble count
(riffle)
300
XS 2
B
XS 3
XS 4:
Pebble count
(riffle)
C
250
XS 5:
Pebble count
(step)
D
C ulvert
XS 6
E
S egm ent
A
B
C
D
E
F
G
H
I
J
K
S egm ent
L ength (ft)
35
23
44
15
14
19
78
14
9
40
37
Table 1—Segment comparisons
XS 7
S egm ent G ra dient
0.071
0.113
0.060
0.094
0.037
0.019
0.056
0.033
0.108
0.041
0.059
Figure 2—Deadwood Tributary North longitudinal profile.
485
490
Relative elevation (feet) A
495
500
505
510
XS 8:
Pebble count
(step)
150
E
E
U ps trea m T ra n s itio n
C u lv ert S eg men t
C
C
C
D is ta nc e a long bed (feet)
200
F
G
I
XS 10:
Pebble count
(riffle)
J
H
R epres en ta tiv e
C h a n n el S eg men t
G
J
K
100
Representative Channel
XS 9:
Pebble count
(riffle)
H
J
50
K
9.1%
11.5%
% D ifferen c e in
G ra d ien t
7.8%
2.0%
1.8%
XS 11
0
Site Evaluations
A—77
n
o
i
t
a
v
e
l
E
)
t
f
(
485
490
495
500
505
510
515
0
1
5
.
1
5
.
2
3
50
Figure 3—HEC-RAS profile.
Elevation (ft)
A—78
0.1217-0.1247
0.1267-0.1360
0.1359-0.1360
0.1277-0.1356
0.1247-0.1277
E
G
H
J
K
1
1
1
2
1
3
# of measured XSs
5
6
2
9
2
5
# of interpolated XSs
2
.
4
6
.
4
5
2 5 7
. . .
5 5 5 5 6
100
8
.
6
*
5
1
.
8
3
.
8
5
.
8
*
5
2
6
.
8
*
5
7
.
8
200
Main Channel Dis tance (ft)
*
5
7
.
7 8
150
*
5
7
8
.
8
*
5
2
1
.
9 9
5
2 5
. .
9 9
0
1
250
1
.
0
1
*
4
.
0
1
6
.
0
1
*
5
8
.
0
1
Stations with decimal values are interpolated cross sections placed along the surveyed profile.
5
7
.
3
*
5
1 3 5
. . .
7 7 7
*
3
3
3
0
.
1 1
1 1
300
*
6
6
6
0
.
1
1
1
.
1
1
350
Ground
W S 10 c fs
W S Qbf
W S Q10
W S Q50
W S Q100
L e ge nd
Obtained using equation from Jarrett (1984): n = 0.39S0.38 R-0.16, where S=stream slope; R=hydraulic radius. Jarrett’s equation only
applied within the following ranges: S = 0.002 to 0.08, R = 0.5 ft to 7 ft. For cross sections outside these ranges, n was computed
either from adjacent sections that fell within the ranges, using the guidance of Arcement and Schneider (1987), or from the HEC-RAS
recommendations for culvert modeling.
1
0.1232-0.1478
C
SegmentRange of Manning’s n values1
Table 2. Summary of segments used for comparisons
Culvert Scour Assessment
Deadwood Creek Tributary North
n
o
i
t
a
v
e
l
E
n
o
i
t
a
v
e
l
E
)
t
f
(
Deadwood Creek Tributary North
Elevation (ft)
0
502
10
504
506
508
510
506
507
508
510
509
511
512
514
513
.
1
3
6
.1247
20
10
.136
.
1
2
4
7
30
20
Station (ft)
40
RS = 9
Station (ft)
30
50
40
.136
.1247
RS = 11
60
50
60
70
B a n k S ta
L e ve e
G ro u n d
W S 1 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
L e ge n d
Bank St a
Ground
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
n
o
i
t
a
v
e
l
E
n
o
i
t
a
v
e
l
E
)
t
f
(
498
10
499
500
502
501
503
504
506
505
504
10
505
506
508
507
509
510
512
511
.1308
20
20
.1341
30
30
Station (ft)
40
.1308
RS = 8
Station (ft)
40
.1341
RS = 10
50
50
60
.1308
60
.1341
70
70
Bank St a
Ground
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
Bank St a
Gr ound
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
Figure 4—Cross-section plots. Only measured cross sections are included. Manning’s n values are included at the top of the cross section. The
stationing (RS) corresponds to the stationing on the HEC-RAS profile. Green arrows define the ineffective flow areas. Black arrows represent
points identified in the field as the bankfull channel boundary. Only those points identified in the field and supported by hydraulic and topographic
analyses are shown below.
Elevation (ft)
)
t
f
(
Elevation (ft)
Elevation (ft)
)
t
f
(
Site Evaluations
A—79
n
o
i
t
a
v
e
l
E
n
o
i
t
a
v
e
l
E
)
t
f
(
Elevation (ft)
496
-20
497
498
500
499
501
502
504
503
498
-20
499
500
502
501
503
504
506
505
-10
-10
0
. .
0 1
1 4
9 7
8
0
.
1
2
2
1
10
.
0
1
9
10
20
Station (ft)
20
RS = 5
30
30
.1221
Station (ft)
.1221
RS = 7
40
40
50
50
60
Bank St a
Ground
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
60
B a n k S ta
In e ff
G ro u n d
W S 1 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
L e ge n d
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
)
t
f
(
Elevation (ft)
20
30
40
50
60
60
L e ge n d
W S Q1 0 0
494
-20
495
496
498
497
499
500
502
501
498
-20
499
500
502
501
-10
0
.
0
1
9
10
. .
1 0
4 1
7 9
8
Station (ft)
20
RS = 4
Station (ft)
30
40
50
Bank St a
Ground
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
B a n k S ta
In e ff
G ro u n d
W S 1 0 c fs
W S Qb f
W S Q1 0
10
.1217
W S Q5 0
0
.1217
503
-10
.1217
504
506
505
RS = 6
Figure 4—Cross-section plots. Only measured cross sections are included. Manning’s n values are included at the top of the cross section. The
stationing (RS) corresponds to the stationing on the HEC-RAS profile. Green arrows define the ineffective flow areas. Black arrows represent
points identified in the field as the bankfull channel boundary. Only those points identified in the field and supported by hydraulic and topographic
analyses are shown below. (continued)
Elevation (ft)
A—80
Elevation (ft)
)
t
f
(
Culvert Scour Assessment
Deadwood Creek Tributary North
n
o
i
t
a
v
e
l
E
n
o
i
t
a
v
e
l
E
)
t
f
(
Deadwood Creek Tributary North
Elevation (ft)
490
-10
491
492
494
493
495
496
498
497
494
-10
495
496
498
497
499
500
502
501
0
0
10
.1232
10
.1232
20
20
Station (ft)
30
.1232
RS = 1
Station (ft)
30
.1232
RS = 3
40
40
50
.1232
50
.1232
60
60
70
Bank St a
Ground
WS 10 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
70
B a n k S ta
In e ff
G ro u n d
W S 1 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
L e ge n d
n
o
i
t
a
v
e
l
E
)
t
f
(
Elevation (ft)
20
30
40
50
60
70
L e ge n d
W S Q1 0 0
490
-10
491
492
494
493
Station (ft)
B a n k S ta
In e ff
G ro u n d
W S 1 0 c fs
W S Qb f
W S Q1 0
10
.1232
W S Q5 0
.1232
495
0
.1232
496
498
497
RS = 2
Figure 4—Cross-section plots. Only measured cross sections are included. Manning’s n values are included at the top of the cross section. The
stationing (RS) corresponds to the stationing on the HEC-RAS profile. Green arrows define the ineffective flow areas. Black arrows represent
points identified in the field as the bankfull channel boundary. Only those points identified in the field and supported by hydraulic and topographic
analyses are shown below. (continued)
Elevation (ft)
)
t
f
(
Site Evaluations
A—81
A—82
.
P
.
W
l
a
t
o
T
)
t
f
(
w
o
l
F
a
e
r
A
q
s
(
0
10
20
30
40
50
60
0
A
50
B
0
A
50
B
Figure 6—Wetted perimeter.
0
10
20
30
40
50
60
D
100
Culvert
C
D
100
Culvert
C
Figure 5—Flow area (total) profile plot.
Flow Area ( sq ft )
Wetted perimeter total ( ft )
)
t
f
E
E
200
G
G
200
Main Channel Distance (ft)
150
F
Main Channel Distance (ft)
150
F
H I
250
250
H I
Flow
J
J
300
300
K
Flow
K
350
350
W.P. Total 10 cfs
W.P. Total Qbf
W.P. Total Q10
W.P. Total Q50
W.P. Total Q100
Legend
Flow Area 10 cfs
Flow Area Qbf
Flow Area Q10
Flow Area Q50
Flow Area Q100
Legend
Culvert Scour Assessment
Deadwood Creek Tributary North
Deadwood Creek Tributary North
p
o
T
h
t
d
i
W
)
t
f
(
r
d
y
H
s
u
i
d
a
R
0.0
0.5
1.0
1.5
2.0
2.5
0
A
50
B
0
A
Figure 8—Top width.
0
10
20
30
40
50
60
50
B
Figure 7—Hydraulic radius.
Hydraulic radius ( ft )
Top width ( ft )
)
t
f
(
D
100
100
Culvert
C
D
Culvert
C
E
E
200
G
G
200
Main Channel Distance (ft)
150
F
Main Channel Distance (ft)
150
F
H I
250
250
H I
J
J
K
300
Flow
300
Flow
K
350
350
Top Width 10 cfs
Top Width Qbf
Top Width Q10
Top Width Q50
Top Width Q100
Legend
Hydr Radius 10 cfs
Hydr Radius Qbf
Hydr Radius Q10
Hydr Radius Q50
Hydr Radius Q100
Legend
Site Evaluations
A—83
A—84
r
a
e
h
S
n
a
h
C
q
s
/
b
l
(
)
t
f
x
a
M
l
h
C
h
t
p
D
50
0.0
0.5
1.0
1.5
2.0
0
A
50
B
D
100
Culvert
C
Figure 10—Shear stress (channel) profile.
0
5
10
15
20
25
30
100
D
E
E
150
F
200
G
Flow
200
G
Main Channel Distance (ft)
150
F
Main Channel Distance (ft)
250
H I
250
H I
J
J
300
K
K
350
Max Chl Dpth Q100
Legend
300
Flow
350
Shear Chan 10 cfs
Shear Chan Qbf
Shear Chan Q10
Shear Chan Q50
Shear Chan Q100
Legend
Max Chl Dpth 10 cfs
Max Chl Dpth Qbf
Max Chl Dpth Q10
Culvert
C
2.5
0
B
Max Chl Dpth Q50
A
3.0
3.5
4.0
Figure 9—Maximum depth.
Max Chan Depth ( ft )
Shear Chan ( lb/sq ft )
)
t
f
(
Culvert Scour Assessment
Deadwood Creek Tributary North
)
s
/
t
f
(
Deadwood Creek Tributary North
l
e
V
l
n
h
C
Velocity channel ( ft/s )
0
A
50
B
D
100
Culvert
C
Figure 11—Velocity (channel) profile plot.
0
2
4
6
8
10
E
G
200
Main Channel Distance (ft)
150
F
H I
250
J
300
Flow
K
350
Vel Chnl 10 cfs
Vel Chnl Qbf
Vel Chnl Q10
Vel Chnl Q50
Vel Chnl Q100
Legend
Site Evaluations
A—85
E (us trans)
H
H
G
25% Q2
E (us trans)
C (culv)
G
J
Flow area (ft2)
Figure 12—Flow area (total).
0
Flow
15Area (ft2)
30
45
60
J
K
H
H
G
E (us trans)
Qbf
E (us trans)
C (culv)
G
J
J
K
E (us trans)
G
H
H
G
10
E (us trans)
C (culv)
50%
of the
values
C (culv)
K
J
K
G
G
E (us trans)
H
50
E (us trans)
C (culv)
Minimum value
25th percentile
H
J
Median (aka 50th percentile)
75th percentile
Maximum value
J
C (culv)
K
A—86
C (culv)
100%
of the
values
J
C (culv)
K
Box Plot Explanation
K
H
H
G
E (us trans)
100
E (us trans)
C (culv)
G
J
K
Culvert Scour Assessment
Deadwood Creek Tributary North
K
J
C (culv)
K
H
E (us trans)
J
H
25% Q2
E (us trans)
C (culv)
G
G
Figure 14—Hydraulic radius.
0
0.5 Radius (ft)
Hydraulic
1
1.5
2
J
K
K
Qbf
E (us trans)
C (culv)
G
Qbf
H
H
E (us trans)
C (culv)
G
J
J
J
J
K
Wetted perimeter (ft)
Hydraulic radius (ft)
2.5
H
Figure 13—Wetted perimeter.
25% Q2
E (us trans)
C (culv)
J
E (us trans)
E (us trans)
H
K
J
G
G
G
K
K
K
K
0
10
E (us trans)
C (culv)
G
10
J
H
H
J
H
H
J
J
E (us trans)
C (culv)
G
K
C (culv)
C (culv)
C (culv)
K
K
G
G
50
E (us trans)
C (culv)
G
50
J
H
H
J
K
K
J
J
H
H
K
K
E (us trans)
E (us trans)
E (us trans)
K
C (culv)
G
H
100
E (us trans)
C (culv)
G
100
J
K
K
J
H
E (us trans)
C (culv)
C (culv)
10 Perimeter (ft)
Wetted
E (us trans)
E (us trans)
20
H
30
J
J
40
C (culv)
C (culv)
H
H
C (culv)
C (culv)
E (us trans)
E (us trans)
G
E (us trans)
C (culv)
C (culv)
G
G
G
G
Deadwood Creek Tributary North
G
H
K
K
50
Site Evaluations
A—87
H
25% Q2
E (us trans)
C (culv)
G
J
J
J
Figure 16—Maximum depth.
0
Maximum Depth (ft)
1
2
3
4
Figure 15­—Top width.
25% Q2
H
K
K
H
H
Qbf
E (us trans)
C (culv)
G
Qbf
E (us trans)
C (culv)
G
J
J
J
K
K
K
K
J
K
Top width (ft)
Maximum depth (ft)
H
E (us trans)
K
C (culv)
C (culv)
G
G
C (culv)
J
E (us trans)
E (us trans)
H
H
H
G
H
H
10
E (us trans)
C (culv)
G
10
E (us trans)
C (culv)
C (culv)
C (culv)
G
G
G
E (us trans)
E (us trans)
H
H
0
J
J
J
J
10
K
K
K
K
20
G
H
H
50
E (us trans)
C (culv)
G
50
E (us trans)
C (culv)
C (culv)
C (culv)
Top Width (ft)
J
J
J
J
30
K
K
K
K
40
E (us trans)
E (us trans)
G
G
C (culv)
C (culv)
G
H
H
100
E (us trans)
C (culv)
G
100
E (us trans)
C (culv)
E (us trans)
E (us trans)
H
H
G
G
E (us trans)
E (us trans)
C (culv)
C (culv)
H
H
G
G
J
J
J
J
A—88
K
K
K
K
50
Culvert Scour Assessment
Deadwood Creek Tributary North
H
H
G
E (us trans)
J
C (culv)
G
H
25% Q2
E (us trans)
C (culv)
E (us trans)
J
Figure 18—Velocity (channel).
0
2
C (culv)
Velocity (ft/sec)
4
6
8
G
G
K
K
J
J
J
H
Qbf
E (us trans)
C (culv)
G
Qbf
G
K
J
J
H
10
E (us trans)
C (culv)
G
10
G
K
J
H
50
E (us trans)
C (culv)
G
50
G
K
K
J
J
H
H
100
E (us trans)
C (culv)
G
100
E (us trans)
J
H
C (culv)
K
J
J
E (us trans)
K
J
J
H
C (culv)
K
E (us trans)
K
H
C (culv)
C (culv)
C (culv)
E (us trans)
K
C (culv)
C (culv)
C (culv)
K
C (culv)
C (culv)
K
K
J
Width-to-depth ratio
Velocity (ft/sec)
10
H
Figure 17—Width-to-depth ratio.
25% Q2
E (us trans)
C (culv)
G
K
K
0
C (culv)
C (culv)
20
H
H
Width-to-depth Ratio
J
J
40
K
60
J
J
G
G
K
E (us trans)
E (us trans)
K
H
E (us trans)
E (us trans)
H
G
G
G
G
H
E (us trans)
E (us trans)
H
H
E (us trans)
E (us trans)
H
G
G
Deadwood Creek Tributary North
K
80
Site Evaluations
A—89
G
E (us trans)
C (culv)
H
H
J
K
K
J
20
40
60
C (culv)
D is c h ar g e (c fs )
E (us trans)
80
H
H
G
100
Qbf
E (us trans)
C (culv)
G
K
K
J
120
J
H
H
G
E (us trans)
C (culv)
J
Culvert (DS pebble count) - riffle
Culvert (US pebble count) - step
US Channel (DS pebble count) - step
US Channel (Mid pebble count) - riffle
US Channel (US pebble count) - riffle
10
E (us trans)
C (culv)
G
J
Figure 20—Excess shear stress.
Excess shear stress is the channel shear divided by the critical shear for bed
entrainment of the D84 particle size. Values of excess shear greater than 1 indicate
bed movement for the D84 particle size.
0
Excess Shear (Applied / tcrit)
0
2
4
6
8
10
12
14
Figure 19—Shear stress (channel).
25% Q2
E (us trans)
C (culv)
G
Shear Stress (lbs/ft2)
0
Shear stress (lbs/ft2)
Excess shear (applied / tcrit)
A—90
10
20
30
K
H
H
G
E (us trans)
50
E (us trans)
C (culv)
G
J
K
H
H
G
E (us trans)
100
E (us trans)
C (culv)
G
J
K
Culvert Scour Assessment
Deadwood Creek Tributary North
K
J
C (culv)
K
J
C (culv)
K
Site Evaluations
Table 3—Sum of squared height difference
Reach
XS LocationUnit type
Culvert
Sum of squared
height difference
Within range of
channel conditions?
US
Step
0.05
Yes
DS
Riffle
0.03
Yes
US
Riffle
0.02
Middle
Riffle
0.03
DS
Step
0.20
Upstream
Table 4—Vertical sinuosity
Segment
LocationVertical Sinuosity (ft/ft)
A
DS channel
1.003
B
DS transition
1.010
C
Culvert
1.004
D
Culvert
1.001
E
US transition
1.032
F
US transition
1.003
G
US channel
1.014
H
US channel
1.001
I
US channel
1.015
J
US channel
1.011
K
US channel
1.008
Table 5—Depth distribution
Reach
XS Location
25% Q2
Culvert
Within range of channel conditions?
US
0
No
DS
0
No
US
4
Middle
20
DS
6
Upstream
Deadwood Creek Tributary North
A—91
Culvert Scour Assessment
Table 6—Habitat unit composition
Percent of surface area
Reach
Pool
Glide
Riffle
Step
Culvert
15%
0%
73%
11%
Upstream Channel
22%
0%
73%
5%
1. 4

1. 0
0. 8
0. 6
0. 4
Residual depth (ft)

0. 2


Segment J
Segment K
Segment I
Segment J
Segment H
Segment I
Segment G
Segment H
US
Culvert
Transition Segment F
Segment D: Segment E:
Segment G
Segment F
DS
Culvert
Transition
Segment ASegment
B:
Segment C:
Segment D
Culvert

Segment C
Culvert
Segment B
DSTransition
Segment A
0. 0



Segment E
US Transition
Residual depth (ft)
1. 2
Segment K
Figure 21—Residual depths.
Table 7—Bed material sorting and skewness
XS
Unit
Reach
Location
Type
Sorting
Culvert
Upstream
Downstream
A—92
Within range
Within range
of channel
of channel
conditions? Skewness conditions?
US
Step
2.15
Yes
0.01
No
DS
Riffle
1.88
Yes
0.28
Yes
US
Riffle
2.26
0.36
Middle
Riffle
2.28
0.19
DS
Step
1.89
0.45
Riffle
1.91
0.42
Deadwood Creek Tributary North
Site Evaluations
Table 8—Large woody debris
Terminology:
Reach
US = Upstream
Pieces/Channel
Width
Culvert
0
Upstream
1.7
View upstream through culvert.
DS = Downstream
RR = Reference reach
XS = Cross section
View downstream towards culvert inlet.
Upstream reference reach—upstream pebble count,
riffle.
Deadwood Creek Tributary North
Upstream reference reach – downstream pebble
count, riffle.
A—93
Culvert Scour Assessment
View downstream from outlet.
A—94
View upstream from confluence with Deadwood Creek.
Deadwood Creek Tributary North
Site Evaluations
Cross section: Upstream Reference Reach – Upstream Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize R ange (mm)
C ount
Item %
C umulative %
12
3
6
7
2
6
3
8
15
9
10
12
6
3
0
0
0
0
0
0
12%
3%
6%
7%
2%
6%
3%
8%
15%
9%
10%
12%
6%
3%
0%
0%
0%
0%
0%
0%
12%
15%
21%
27%
29%
35%
38%
46%
61%
70%
79%
91%
97%
100%
100%
100%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
> 4096
16
100%
14
90%
Frequency
70%
10
60%
8
50%
6
40%
30%
4
20%
2
Cumulative Frequency
80%
12
10%
>4096
2048-4096
512-1024
1024-2048
362-512
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
16-22.6
8-11.3
11.3-16
5.7-8
<2
4-5.7
<2
0%
2-4
0
2-4
4 - 5.7
5.7 - 8
> 4096
32 -45
45-64
64- 90
8 - 11.3
90 - 128
11.316
- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
512 - 1024
1024
2048
- 2048
- 4096
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
4
35
105
162
218
Deadwood Creek Tributary North
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
12%
58%
30%
0%
0%
2.26
Skewness Coefficient: 0.36
A—95
Culvert Scour Assessment
Cross section: Upstream Reference Reach – Middle Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize C las s (mm)
C ount
Item %
C umulative %
13
7
10
7
6
3
5
13
5
8
7
9
4
0
0
0
0
0
0
0
13%
7%
10%
7%
6%
3%
5%
13%
5%
8%
7%
9%
4%
0%
0%
0%
0%
0%
0%
0%
13%
21%
31%
38%
44%
47%
53%
66%
71%
79%
87%
96%
100%
100%
100%
100%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
Bedrock
100%
14
90%
12
Frequency
70%
60%
8
50%
6
40%
30%
4
Cumulative Frequency
80%
10
20%
2
10%
Bedrock
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
11.3-16
16-22.6
5.7-8
2-4
4 - 5.7
5.7 - 8
32 - 45
45 -64
64- 90
8 - 11.3
90 - 128
Bedrock
11.316
- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
Particle Size Category (mm)
512 - 1024
1024
2048
- 2048
- 4096
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
3
19
81
124
154
A—96
8-11.3
2-4
<2
4-5.7
0%
<2
0
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
13%
66%
21%
0%
0%
2.28
Skewness Coefficient: 0.19
Deadwood Creek Tributary North
Site Evaluations
Cross section: Upstream Reference Reach – Downstream Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize C las s (mm)
C ount
Item %
C umulative %
4
4
5
2
4
2
4
12
6
10
11
21
10
3
1
1
0
0
0
0
4%
4%
5%
2%
4%
2%
4%
12%
6%
10%
11%
21%
10%
3%
1%
1%
0%
0%
0%
0%
4%
8%
13%
15%
19%
21%
25%
37%
43%
53%
64%
85%
95%
98%
99%
100%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
Bedrock
25
100%
90%
80%
Frequency
70%
15
60%
50%
10
40%
30%
5
20%
Cumulative Frequency
20
10%
Bedrock
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
11.3-16
16-22.6
5.7-8
8-11.3
2-4
<2
4-5.7
0%
<2
0
2-4
4 - 5.7
5.7 - 8
32 -45
45- 64
64 - 90
8 - 11.3
90 - 128
Bedrock
11.316
- 16
- 22.6
22.6 - 32
128 180
- 180
256
- 256
362
- 362
- 512
512 - 1024
Particle Size Category (mm)
1024
2048
- 2048
- 4096
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
2.5
9
58
126
180
437
Deadwood Creek Tributary North
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
4%
49%
45%
2%
0%
1.89
Skewness Coefficient: 0.45
A—97
Culvert Scour Assessment
Cross section: Culvert – Upstream Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize C las s (mm)
C ount
Item %
C umulative %
1
0
2
3
2
1
12
6
8
3
12
7
12
4
6
3
14
0
0
0
1%
0%
2%
3%
2%
1%
13%
6%
8%
3%
13%
7%
13%
4%
6%
3%
15%
0%
0%
0%
1%
1%
3%
6%
8%
9%
22%
28%
36%
40%
52%
59%
72%
76%
82%
85%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
Bedrock
16
100%
14
90%
Frequency
Frequency
70%
10
60%
8
50%
6
40%
30%
4
20%
2
10%
Bedrock
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
11.3-16
16-22.6
5.7-8
8-11.3
2-4
<2
4-5.7
0%
<2
0
2-4
4 - 5.7
5.7 - 8
32 - 45
45 -64
64- 90
8 - 11.3
90 - 128
Bedrock
11.316
- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362- 512
512 - 1024
10242048
- 2048
- 4096
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
7
19
86
444
768
768
A—98
Cumulative Frequency
80%
12
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
1%
39%
36%
24%
0%
2.15
Skewness Coefficient: 0.01
Deadwood Creek Tributary North
Site Evaluations
Cross section: Culvert – Downstream Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize C las s (mm)
C ount
Item %
C umulative %
2
4
2
6
4
8
5
9
5
13
10
12
11
9
0
0
0
0
0
0
2%
4%
2%
6%
4%
8%
5%
9%
5%
13%
10%
12%
11%
9%
0%
0%
0%
0%
0%
0%
2%
6%
8%
14%
18%
26%
31%
40%
45%
58%
68%
80%
91%
100%
100%
100%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
Bedrock
14
100%
90%
12
Frequency
Frequency
70%
60%
8
50%
6
40%
30%
4
20%
2
Cumulative Frequency
80%
10
10%
Bedrock
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
16-22.6
11.3-16
5.7-8
8-11.3
<2
4-5.7
<2
0%
2-4
0
2-4
4 - 5.7
5.7 - 8
32 - 45
45 - 64
64 - 90
8 - 11.3
90 - 128
Bedrock
11.316
- 16
- 22.6
22.6 - 32
128 180
- 180
256
- 256
362
- 362
- 512
512 - 1024
Particle Size Category (mm)
10242048
- 2048
- 4096
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
4
10
52
147
214
218
Deadwood Creek Tributary North
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
2%
56%
42%
0%
0%
1.88
Skewness Coefficient: 0.28
A—99
Culvert Scour Assessment
Cross section: Downstream of culvert – Only Pebble Count
Material
sand
very fine gravel
fine gravel
fine gravel
medium gravel
medium gravel
coarse gravel
coarse gravel
very coarse gravel
very coarse gravel
small cobble
medium cobble
large cobble
very large cobble
small boulder
small boulder
medium boulder
large boulder
very large boulder
bedrock
S ize C las s (mm)
C ount
Item %
C umulative %
5
7
2
1
2
4
8
7
7
13
13
17
8
4
1
0
0
0
0
0
5%
7%
2%
1%
2%
4%
8%
7%
7%
13%
13%
17%
8%
4%
1%
0%
0%
0%
0%
0%
5%
12%
14%
15%
17%
21%
29%
36%
43%
57%
70%
87%
95%
99%
100%
100%
100%
100%
100%
100%
<2
2-4
4 - 5.7
5.7 - 8
8 - 11.3
11.3 - 16
16 - 22.6
22.6 - 32
32 - 45
45 - 64
64 - 90
90 - 128
128 - 180
180 - 256
256 - 362
362 - 512
512 - 1024
1024 - 2048
2048 - 4096
Bedrock
100%
16
90%
14
80%
70%
Frequency
12
60%
10
50%
8
40%
6
30%
4
20%
2
10%
Bedrock
2048-4096
512-1024
1024-2048
362-512
256-362
180-256
128-180
64-90
90-128
45-64
32-45
22.6-32
16-22.6
8-11.3
11.3-16
5.7-8
<2
4-5.7
<2
0%
2-4
0
Cumulative Frequency
18
2-4
4 - 5.7
5.7 - 8
32 - 45
45 -64
64- 90
8 - 11.3
90 - 128
Bedrock
11.316
- 16
- 22.6
22.6 - 32
128 180
- 180
256
- 256
362
- 362- 512
512 - 1024
Particle Size Category (mm)
1024
2048
- 2048
- 4096
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
2
9
55
122
181
309
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
5%
52%
42%
1%
0%
1.91
Skewness Coefficient: 0.42
*This pebble count was not used in the analysis because the downstream reach was not used as a reference reach
A—100
Deadwood Creek Tributary North