Site Evaluations
Deadwood Creek Tributary South
Site Information
Site Location:
Coast Range, S Willamette Valley, Deadwood Road
Year Installed:
2000
Lat/Long:
123°41’19.22”W
Watershed Area (mi2):0.21
44°13’11.30”N
Stream Slope (ft/ft) : 0.0932
Channel Type:
Step-pool
Bankfull Width (ft): 6.6
Survey Date:
March 7, 2007
1
1
Water surface slope extending up to 20 channel widths up and downstream of crossing.
Culvert Information
Culvert Type:
Circular
Culvert Material: Annular CMP
Culvert Width:
7.5 ft
Outlet Type:
Projecting
Culvert Length:
63 ft
Inlet Type:
Projecting
Pipe Slope (structure slope): 0.126
Culvert Bed Slope: 0.066
(First hydraulic control upstream of inlet to first hydraulic control downstream of outlet.)
Culvert width as a percentage of bankfull width: 1.13
Alignment Conditions: On-line with natural channel.
Bed Conditions: Material scoured out of upstream 1/2 of pipe. Coarse material remaining in pipe.
Pipe Condition: Some structure joints slightly open but no leaking. Minor rust.
Hydrology
Discharge (cfs) for indicated recurrence interval
25% 2-yr
2-year
Qbf2
5-year
10-year
50-year
100-year
5
18
18
26
32
46
52
Bankfull flow estimated by matching modeled water surface elevations to field-identified bankfull
elevations.
2
Deadwood Creek Tributary South
A—101
Culvert Scour Assessment
Points represent survey points
Figure 1­—Plan view map.
A—102
Deadwood Creek Tributary South
Site Evaluations
History
The Deadwood Tributary South culvert was
installed in August 2000. Material was placed in
the culvert by hand using a wheelbarrow. 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 (3to 4-inch) thalweg.
The original channel alignment was directly
on the original stream channel. No change
in alignment was made but the channel was
widened upstream for construction access. The
crossing was located at a dual grade break;
steeper upstream, large scour pool downstream,
and a steeper average gradient downstream. The
downstream channel was poorly defined.
Construction-related alterations changed the
upstream channel from a confined, wood grade
controlled, and heavily vegetated channel to
a flattened, exposed, and wider channel. The
downstream channel was disturbed by equipment
due to the need for access to reach the scour
pool.
No significant maintenance of the site has
occurred since construction. Branches from road
clearing were dumped at the inlet and apparently
plugged it during a storm/sediment transport
event. Maintenance activities related to this event
are unknown. Wood and rocks were hand placed
after construction to help define the channel
within the “delta” area.
The above information furnished by
Kim Johansen, USFS.
Deadwood Creek Tributary South
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 Creek South Tributary culvert
is a closed round pipe that projects from the
road fill. The culvert showed signs of adjustment
postconstruction. The upper half of the pipe has
scoured to the culvert base. About 30 feet down
the pipe, large angular material remains in place,
presumably from the initial installation. Towards
the outlet, material from upstream has deposited
on top of the original fill, altering the grade. As
a result, the conveyance through the outlet has
decreased due to the adjustment in the invert.
There was supercritical flow in the upstream half
of the culvert at the time of the survey and the
modeling suggests that this condition persists
even at high flows. The upstream representative channel consisted
of a high gradient step-pool channel with a narrow
and low active flood-plain surface. The presence
of large wood in the stream provides structure to
the channel, making up the majority of the grade
control. In addition to wood, large boulders also
add to the structure of the steps. Plunge pools
follow most steps and are interspersed by steep
riffles.
At the outlet to the culvert, the channel drops over
a steep riffle. Downstream of the outlet there is
a steep riprap step/cascade possibly built during
or following construction to control the grade up
to the outlet. After the step, the stream flattens
out before entering the flood plain of Deadwood
Creek. Large quantities of brush from roadside
clearing were present downstream of the
crossing.
A—103
Culvert Scour Assessment
Survey Summary
Eleven cross sections and a longitudinal profile
were surveyed along Deadwood Creek South
Tributary in March 2007 to characterize the
culvert and an upstream reference reach. No
downstream reference reach was established
due to the proximity of the crossing with the
confluence of Deadwood Creek. Lacking bed
material and therefore bedforms, only one
reference section was taken through 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 boundary, two through steps and
one through a riffle.
A single representative cross section and pebble
count were taken through a downstream riffle
below the riprap step but these were not used in
the analysis because of potential influence from
backwater from Deadwood Creek.
Profile Analysis Segment Summary
The profile analysis resulted in a total of 14
profile segments. The culvert consisted of two
profile segments. The upstream segment in
the culvert was comparable to two different
representative profile segments in the upstream
channel. The downstream segment in the culvert
had no measured cross sections so was not
used for comparisons. The upstream transition
segment was comparable to two representative
profile segments in the upstream channel.
Three different downstream transition segments
were comparable to a total of four different
representative profile segments in the upstream
channel. This downstream transition area
A—104
consisted of three distinct profile segments where
the stream falls off quickly from the culvert outlet
to the mainstem valley floor of Deadwood Creek.
See figure 2 and table 1.
Scour Conditions
Observed conditions
Structure scour – The upstream half of the pipe
was scoured to the culvert base. Supercritical
flow was present along the exposed culvert base
at the time of the survey.
Culvert bed adjustment – The culvert bed has
scoured placed material out of the upstream
half of the pipe. This has resulted in a slope
adjustment of the culvert bed, which is now
about half of the slope of the structure itself.
Material still remains in the downstream portion
of the pipe, some of the material appears to
have aggraded in the downstream portion and
may have been sourced from the scour in the
upstream portion.
Profile characteristics – The profile is concave
at the crossing but convex downstream of the
outlet (figure 2). The profile was described as a
“dual grade break” by the designer (see History
section). The site is located at the transition
from the small, confined valley of the tributary
to the broader valley of mainstem Deadwood
Creek. The profile shape is very likely an artifact
of the previous culvert at this site, which had a
large scour pool at the outlet and then dropped
off steeply to Deadwood Creek. The steep
downstream segment is now a steep riprap step.
Residual depths – The one residual depth in the
culvert is located in a profile segment that has
no comparable profile segment in the natural
channel; however, this depth is at the lower end
of the range of residual depths found within all
the profile segments in the channel outside the
Deadwood Creek Tributary South
Site Evaluations
crossing (figure 21). Transition segments have
residual depths that do not vary substantially from
corresponding profile segments.
Substrate – The culvert bed material distribution
(downstream half) has less sand and fine gravel
than the bed material in the natural channel. The
amount of coarse material is within the range of
the natural channel. The skewness value is within
the range of the natural channel. The culvert
sorting value is less poorly sorted than the natural
channel, indicating that it has less representation
of the range of size classes.
Predicted conditions
Cross-section characteristics – Cross-section
characteristics in the culvert are very different
in the upstream (scoured) portion of the culvert
versus the downstream portion of the culvert
(figures 5 through 9). In general, the upstream
portion of the pipe has dramatically reduced flow
area, wetted perimeter, hydraulic radius, top
width, and maximum depth. The downstream
portion has conditions that are more similar
to the natural channel but generally have less
variability. The box plots (figures 12 through
17) do not fully exhibit this pattern because
the upstream profile segment in the culvert (F)
extends downstream beyond the scoured portion
of the pipe. The upstream transition segment
has similar conditions to corresponding profile
segments except for depth and hydraulic radius,
which are greater in the transition segment. The
downstream transition segments are mostly within
the range of their natural counterparts except for
top width, for which they have greater values.
Excess shear – The excess shear analysis
suggests that bed material in the culvert is
mobilized less frequently than material in the
natural channel (figure 20). Past scour of culvert
material may have served to stabilize the bed by
scouring out smaller material and leaving larger
material that is capable of withstanding high
flows.
Velocity – Velocity in the upper portion of the
culvert is extremely high in relation to the natural
channel (figure 11). The downstream portion of
the culvert and the transition segments have
velocities that are more in line with the channel
outside the crossing.
Scour summary
This site has very high gradient (up to 12 percent)
that likely pushes the limits of the HEC-RAS
model; and so results need to be interpreted
accordingly. However, the flow conditions
modeled in the culvert at this site appear to
match well the observations of flow conditions at
the time of the survey with respect to the rapid
shallow flow in the scoured portion of the pipe.
The scoured upper portion of the pipe is likely
related to the steepness of the culvert (12 percent
compared to average reach slope of 9 percent)
and the size of the material that was placed
during construction. Material placement at this
site was conducted by hand using a wheelbarrow
and this may have limited the size of material that
was able to be placed inside the structure.
AOP Conditions
Shear stress – Modeled shear stress in the
culvert has a greater range than the natural
channel at the Q10 and above, with more extreme
(lower as well as higher) values (figure 19).
Transition segments do not differ significantly
from the natural channel.
Deadwood Creek Tributary South
Cross-section complexity – The sum of squared
height difference is greater in the culvert than in
the channel cross sections (table 3).
A—105
Culvert Scour Assessment
Profile complexity – Vertical sinuosity in the
culvert is considerably less than corresponding
profile segments (H and J) (table 4). The
upstream transition segment (G) is also less than
corresponding profile segments. The downstream
transition segments (B, C, and D) have vertical
sinuosities that are similar to or above those
found in their natural channel counterparts.
Depth distribution – The availability of shallow
channel margin habitat in the culvert at the 25
percent Q2 is within the range of that found in the
channel outside the crossing (table 5).
Habitat units – The culvert is nearly all riffle,
whereas the channel outside the crossing has
20-percent pool habitat (table 6).
Residual depths – The one residual depth in the
culvert is located in a profile segment that has
no comparable profile segment in the natural
channel; however, this depth is at the lower end
of the range of residual depths found within all
the profile segments in the channel outside the
crossing (figure 21). Transition segments have
residual depths that do not vary substantially from
corresponding profile segments.
Substrate – The culvert bed material distribution
(downstream half) has less sand and fine gravel
than the bed material in the natural channel. The
amount of coarse material is within the range of
the natural channel. The skewness value is within
the range of the natural channel. The culvert
sorting value is less poorly sorted than the natural
channel, indicating that it has less representation
of the range of size classes.
Large woody debris – There was a small
amount of LWD present in the culvert at the
downstream end (Table 8). The representative
channel had high LWD abundance. LWD was
A—106
the primary factor forming 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.
AOP summary
Upstream of the culvert, the step-pool channel
has high complexity that is driven by the
abundance of woody debris that forms the steps.
If fish could pass the reach at the crossing, there
is high quality and passable habitat upstream.
In the current condition, fish passage would be
blocked by the scour in the upstream portion
of the pipe. The downstream riprap step is
also likely to present a barrier to upstream fish
migration. Even in the downstream portion of
the pipe where material remains, the bed is fairly
uniform, and lacks the step-pool character and
complexity of the natural channel. There are also
no channel banks in the culvert that would allow
for terrestrial organism passage.
Design Considerations
This is a steep stream and an even steeper
culvert, and a very challenging installation to keep
from scouring. Regrading the profile to eliminate
the dual grade break may avoid the steeper
sections that currently pose a passage issue for
migrating fish. Using an open-bottom pipe and
constructing stable steps through the crossing
may provide more stability and scour resistance.
Constructing channel banks within the pipe would
allow for terrestrial organism passage. A series
of wood and rock steps between the outlet and
Deadwood Creek similar to those above the
culvert would also improve passage conditions.
Vegetation-clearing activities along the road
should avoid depositing material in the inlet or
outlet areas. This material can plug the culvert
and can affect fish passage conditions.
Deadwood Creek Tributary South
Relative Elevation (ft)
Deadwood Creek Tributary South
500
450
400
A
XS 1
350
B
C
XS 3
D
XS 2:
Pebble count
(riffle)
Rip-rap step
F
F
U p s tre a m T ra n s itio n
G
G
D o w n s tre a m T ra n s itio n
B
C
D
D
C u lv e rt S e g m e n t
Table 1. Segment comparisons
3.9%
23.9%
15.4%
25.8%
0.1%
2.8%
11.0%
4.3%
I
N
M
I
J
N
F
250
Scoured portion of
culvert
XS 5 XS 6
G
J
150
46
12
J
K
20
27
I
N
28
H
5
26
G
M
62
F
26
12
E
L
17
12
C
D
11
B
L e n g th ( f t)
K
L
M
0 .0 9 7
0 .2 6 9
0 .0 8 9
0 .1 2 6
0 .0 9 1
0 .1 5 5
0 .0 7 2
0 .1 3 1
0 .0 6 9
0 .0 5 4
0 .1 0 2
0 .1 5 9
0 .2 6 9
0 .0 5 4
S e g m e n t G r a d ie n t
100
XS 9:
Pebble count
(riffle)
Representative Channel
XS 8:
Pebble count
(step)
S egm ent
I
36
200
XS 7
H
A
S egm ent
D is ta nc e a long bed (feet)
% D iffe re n c e in
G ra d ie n t
H
J
R e p re s e n ta tiv e
C hannel S egment
C ulvert
XS 4:
Pebble count
(riffle)
300
E
Figure 2—Deadwood Creek Tributary South longitudinal profile.
470
480
490 elevation (feet)
Relative
500
510
520
530
50
XS 10:
Pebble count
(riffle)
XS 11
N
0
Site Evaluations
A—107
A—108
Deadwood Creek Tributary South
n
o
i
t
a
v
e
l
E
)
t
f
(
C
D
F
G
H
I
J
M
N
0.1597
0.1597
0.1597
0.1597
0.1597
0.1597
0.0240-0.1597
0.1516-0.1597
0.1597
0.1597
2
1
1
1
1
1
2
1
1
1
2
2
6
4
5
6
8
4
2
2
# of interpolated XSs
480
490
500
510
520
0
5
.
1
*
5
1 3
. .
2 2 2
8
.
2
5 7 8
. . .
3 3 3
50
4
1
.
4
5
2
.
4
3
.
4
4
.
4
100
5
4
.
4
5
.
4
5
3 7
. .
5 5
*
5
2 5
. .
6 6
*
5
3
.
7
6
.
7
5
8
.
7
1
.
8
2
.
8
200
Main Channel Dis tance (ft)
5
0
.
7
150
*
9
9
9
9
2
.
8
4 6
. .
8 8
Figure 3—HEC-RAS profile.
Stations with decimal values are interpolated cross sections placed along the surveyed profile.
1
9
1
.
9
8
1 2
. .
9 9
250
*
4
.
9
5
.
9
3
.
0
1
1
.
1 1
1 1
300
Obtained using equation from Jarrett (1984): n = 0.39S0.38R-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.
B
SegmentRange of Manning’s n values1 # of measured XSs
Table 2—Summary of segments used for comparisons
350
Ground
W S 25% Q2
W S Qbf
W S Q10
W S Q50
W S Q100
L e ge nd
Culvert Scour Assessment
)
t
f
(
Deadwood Creek Tributary South
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
508
0
.1597
10
10
.1597
20
20
30
Station (ft)
30
.1597
RS = 9
Station (ft)
.1597
40
40
.1597
50
50
Bank St a
Ground
WS 25% Q2
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
Bank St a
Ground
WS 25% Q2
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
n
o
i
t
a
v
e
l
E
)
t
f
(
Elevation (ft)
0
502
503
504
505
506
507
508
514
515
516
517
518
519
520
0
10
10
.1597
.1597
.1597
Station (ft)
30
.1597
30
RS = 8
Station (ft)
20
20
RS = 10
.
1
5
9
7
40
40
.
1
5
9
7
50
50
L e ge nd
Bank St a
Ground
WS 25% Q2
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
Bank St a
Gr ound
WS 25% Q2
WS Qbf
WS Q10
WS Q50
WS Q100
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)
509
510
511
0
.1597
n
o
i
t
a
v
e
l
E
Elevation (ft)
512
513
514
514
515
516
517
518
519
520
RS = 11
)
t
f
(
Site Evaluations
A—109
n
o
i
t
a
v
e
l
E
)
t
f
(
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
A—110
0
10
.1597
10
20
20
Station (ft)
.1597
RS = 5
Station (ft)
30
30
40
40
.1597
.1597
50
50
B a n k S ta
In e ff
G ro u n d
WS 25% Q 2
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 25% Q2
WS Qbf
WS Q10
WS Q50
WS Q100
L e ge nd
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
Elevation (ft)
0
492
-20
493
494
495
496
497
498
497
498
499
500
501
502
503
-10
10
.1597
Station (ft)
30
.1597
0
Station (ft)
10
.1347
RS = 4
Note: n values for first profile.
20
.1597
RS = 6
20
40
30
50
Bank St a
Ground
WS 25% Q2
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
WS 25% Q 2
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
L e ge n d
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)
495
496
497
498
0
.1597
RS = 7
Elevation (ft)
499
500
501
498
499
500
501
502
503
504
.1597
)
t
f
(
Culvert Scour Assessment
Deadwood Creek Tributary South
)
t
f
(
Deadwood Creek Tributary South
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
482
10
10
.1597
20
30
Station (ft)
RS = 1
Station (ft)
.1597
20
.1597
30
40
40
.1597
.1597
50
50
.
1
5
9
7
Bank St a
Ground
WS 25% Q2
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
n
o
L e ge n d i
t
W S Q1 0 0
a
W S Q5 0
v
W S Q1 0 e
W S Qb f l
E
WS 25% Q 2
Elevation (ft)
487
10
488
489
490
491
492
493
20
.1597
30
Station (ft)
.1597
RS = 2
40
50
.1597
60
L e ge n d
B a n k S ta
In e ff
G ro u n d
WS 25% Q 2
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
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)
483
484
485
486
487
0
0
488
490
491
492
493
494
495
496
RS = 3
)
t
f
(
Site Evaluations
A—111
A—112
.
P
.
W
l
a
t
o
T
0
5
10
15
20
25
30
0
A B C D
50
E
100
Culvert
F
0
0
A B C D
50
E
Figure 6—Wetted perimeter.
W.P. total (ft)
10
20
30
40
50
100
Culvert
F
Figure 5—Flow Area (total) profile plot.
Flow area (sq ft)
)
t
f
(
w
o
l
F
a
e
r
A
q
s
(
)
t
f
G
G
I
200
Flow
I
200
Flow
Main Channel Distance (ft)
150
H
Main Channel Distance (ft)
150
H
J
J
250
K
250
K
L
M
300
300
L M
N
N
350
350
W.P. Total 25% Q2
W.P. Total Qbf
W.P. Total Q10
W.P. Total Q50
W.P. Total Q100
Legend
Flow Area 25% Q2
Flow Area Qbf
Flow Area Q10
Flow Area Q50
Flow Area Q100
Legend
Culvert Scour Assessment
Deadwood Creek Tributary South
Deadwood Creek Tributary South
p
o
T
h
t
d
i
W
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0
A B C D
50
E
Top width (ft)
A—113
0
A B C D
Figure 8—Top width.
0
10
20
30
40
50
50
E
Figure 7—Hydraulic radius.
Hydraulic radius (ft)
)
t
f
(
r
d
y
H
s
u
i
d
a
R
)
t
f
(
100
Culvert
F
100
Culvert
F
150
H
200
Flow
I
G
I
200
Flow
Main Channel Distance (ft)
150
H
Main Channel Distance (ft)
G
J
J
250
K
250
K
L M
N
N
300
300
L M
350
350
Top Width 25% Q2
Top Width Qbf
Top Width Q10
Top Width Q50
Top Width Q100
Legend
Hydr Radius 25% Q2
Hydr Radius Qbf
Hydr Radius Q10
Hydr Radius Q50
Hydr Radius Q100
Legend
Site Evaluations
A—114
r
a
e
h
S
n
a
h
C
q
s
/
b
l
(
100
G
150
H
I
200
Flow
J
J
250
K
300
L M
N
N
350
Max Chl Dpth Q100
Legend
0.0
0.5
1.0
1.5
2.0
0
0
A B C D
50
E
100
Culvert
F
Figure 10—Shear stress (channel) profile.
Shear channel (lb/sq ft)
5
10
15
20
25
30
35
G
I
200
Flow
Main Channel Distance (ft)
150
H
Main Channel Distance (ft)
250
K
300
L M
350
Shear Chan 25% Q2
Shear Chan Qbf
Shear Chan Q10
Shear Chan Q50
Shear Chan Q100
Legend
Max Chl Dpth 25% Q2
Max Chl Dpth Qbf
Max Chl Dpth Q10
50
Culvert
F
2.5
E
Max Chl Dpth Q50
0
A B C D
3.0
3.5
4.0
Figure 9—Maximum depth.
Maximum channel depth (ft)
)
t
f
x
a
M
l
h
C
h
t
p
D
)
t
f
(
Culvert Scour Assessment
Deadwood Creek Tributary South
Deadwood Creek Tributary South
l
e
V
l
n
h
C
)
s
/
t
f
(
0
0
50
A B C D
E
Culvert
100
F
Figure 11—Velocity (channel) profile plot.
Velocity channel (ft/s)
2
4
6
8
10
12
G
I
200
Flow
Main Channel Distance (ft)
150
H
J
250
K
L M
300
N
350
Vel Chnl 25% Q2
Vel Chnl Qbf
Vel Chnl Q10
Vel Chnl Q50
Vel Chnl Q100
Legend
Site Evaluations
A—115
12
18
24
30
H
I
J M N
25% Q2
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Figure 12—Flow area (total).
0
6
Flow Area (ft2)
Flow area (ft2)
H
I
J M N
100%
of the
values
50%
of the
values
H
I
J
M N
Minimum value
25th percentile
H
I
Median (aka 50th percentile)
J
M N
H
I
J M N
Qbf
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q10
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q50
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
A—116
75th percentile
Maximum value
Box Plot Explanation
Culvert Scour Assessment
Deadwood Creek Tributary South
10
15
20
25
Deadwood Creek Tributary South
H
I
J M N
25% Q2
Hydraulic radius (ft)
H
I
25% Q2
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Figure 14—Hydraulic radius.
0
0.4 Radius (ft)
Hydraulic
0.8
1.2
1.6
2
J
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Figure 13—Wetted perimeter.
0
H
I
J M N
H
I
J
M N
H
I
J
M N
H
I
J M N
M N
Qbf
H
I
J M N
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q10
H
I
J M N
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q50
H
I
J M N
G (us trans)
B (ds
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
H
I
J M N
G (us trans)
B (ds
trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
5 Perimeter (ft)
Wetted
Wetted perimeter (ft)
Qbf
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q10
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q50
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
Site Evaluations
A—117
Maximum depth (ft)
H
I
25% Q2
J
25% Q2
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Figure 16—Maximum depth.
0
I
J M N
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
Maximum Depth (ft)
1
2
3
4
H
F (culv)
Figure 15—Top width.
0
5
H
I
J M N
H
I
J
M N
H
I
J
M N
H
I
J M N
M N
H
Qbf
I
J M N
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
H
Q10
I
J M N
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
H
Q50
I
J M N
G (us trans)
B (ds
C trans)
(ds
D (ds
trans)
trans)
F (culv)
H
Q100
I
J M N
G (us trans)
B (ds
trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
Top Width (ft)
Top width (ft)
Qbf
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q10
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q50
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
A—118
10
15
20
Culvert Scour Assessment
Deadwood Creek Tributary South
20
30
40
50
60
Deadwood Creek Tributary South
H
I
J M N
25% Q2
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Velocity (ft/sec)
H
I
J M N
25% Q2
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Figure 18—Velocity (channel).
0
Velocity
3 (ft/sec)
6
9
12
Figure 17—Width-to-depth ratio.
0
H
I
J M N
H
I
J
M N
H
I
J
M N
H
I
J M N
Qbf
H
I
J M N
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q10
H
I
J
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
M N
Q50
H
I
J
G (us trans)
B (ds
C trans)
(ds
D (ds
trans)
trans)
F (culv)
M N
H
Q100
I
J M N
G (us trans)
B (ds
trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
Width-to-depth
ratio
10
Width-to-depth ratio
Qbf
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Q10
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q50
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
Site Evaluations
A—119
7
14
H
I
J M N
25% Q2
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
Excess shear (applied/tcrit)
0
H
I
J M N
H
I
10
20
30
Dis charge (cfs )
40
50
Qbf
60
G (us trans)
B (ds
trans)
C (ds
D (ds
trans)
trans)
F (culv)
J
DS Channel - riffle
Culvert - riffle
US Channel (DS pebble count) - step
US Channel (Mid pebble count) - riffle
US Channel (US pebble count) - riffle
Q10
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
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
5
Excess Shear (Applied / tcrit)
10
15
20
25
Figure 19—Shear stress (channel).
0
Shear Stress (lbs/ft2)
Shear stress ((lbs/ft2)
M N
H
I
J
M N
H
I
J M N
Q50
B (ds
G (us trans)
C trans)
(ds
D (ds
trans)
trans)
F (culv)
Q100
B (ds
trans)
G (us trans)
C (ds
D (ds
trans)
trans)
F (culv)
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
B (ds trans)
C (ds trans)
D (ds trans)
F (culv)
G (us trans)
H
I
J
M
N
A—120
21
28
35
Culvert Scour Assessment
Deadwood Creek Tributary South
Site Evaluations
Table 3—Sum of squared height difference
Reach
XS LocationUnit type
Sum of squared
height difference
Within range of
channel conditions?
No
Culvert
Riffle
0.09
Upstream
US
Riffle
0.03
Middle
Riffle
0.06
DS
Step
0.05
Riffle
0.02
Downstream Table 4—Vertical sinuosity
Segment
LocationVertical Sinuosity (ft/ft)
A
DS channel
1.003
B
DS transition
1.024
C
DS transition
1.094
D
DS transition
1.032
E
Culvert
1.003
F
Culvert
1.005
G
US transition
1.020
H
US channel
1.057
I
US channel
1.029
J
US channel
1.021
K
US channel
1.036
L
US channel
1.015
M
US channel
1.028
N
US channel
1.042
Table 5—Depth distribution
Reach
XS Location
25% Q2
Culvert
US
4
Middle
0
DS
2
Upstream
5
Downstream Deadwood Creek Tributary South
Within range of
channel conditions?
Yes
6
A—121
Culvert Scour Assessment
Table 6—Habitat unit composition
Percent of surface area
Reach
Pool Glide
Riffle
Step
Culvert
0%
0%
95%
5%
Upstream Channel
20%
0%
75%
1%
1.4

1.0

0.8


0.6

Residual
depth (ft)
0.4




Segment N
Segment M
Segment L
Segment K
Segment J
Segment I

Segment H




Segment G
US Transition
Segment C
DS transition
Segment B
DS transition
Segment A
0.0

Segment F
Culvert


Segment E
Culvert

0.2
Segment D
DS transition
Residual Depth ((ft)
1.2
Culvert
Culvert
SegmentI Segment J Segment KSegment L
Segment MSegment N
Segment E:Segment F: TransitionSegment H
Transition Transition Transition
Segment B:Segment
DS
C:Segment
DS
D: DS
Segment G: US
Segment A
Figure 21—Residual depths.
Table 7—Bed material sorting and skewness
XSUnit
Reach
Location
Type
Sorting
Culvert
Upstream
Downstream A—122
Within range of channel Skewness
conditions?
Riffle
1.57
No
0.29
US
Riffle
2.05
0.44
Middle
Riffle
2.01
0.25
DS
Step
2.53
0.28
Riffle
1.80
0.34
Within range
of channel
conditions?
Yes
Deadwood Creek Tributary South
Site Evaluations
Table 8—Large woody debris
Reach
Pieces/Channel Width
Culvert
0.21
Upstream
2.01
Terminology:
US = Upstream
DS = Downstream
RR = Reference reach
XS = Cross section
View upstream through culvert.
View downstream through culvert.
Deadwood Creek Tributary South
A—123
Culvert Scour Assessment
View upstream in culvert.
View downstream in culvert.
View downstream from upstream end of upstream reference reach.
View upstream near downstream end of
upstream reference reach.
Upstream reference reach – middle pebble
View downstream from road.
count location.
A—124
Deadwood Creek Tributary South
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 %
8
7
4
7
6
9
3
9
17
16
15
8
1
2
0
0
0
0
0
0
7%
6%
4%
6%
5%
8%
3%
8%
15%
14%
13%
7%
1%
2%
0%
0%
0%
0%
0%
0%
7%
13%
17%
23%
29%
37%
39%
47%
63%
77%
90%
97%
98%
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
100%
16
90%
14
80%
70%
Frequency
12
60%
10
50%
8
40%
Frequency
6
30%
4
20%
2
10%
Cumulative Frequency
>4096
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
Cumulative Frequency
18
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
Particle Size Category (mm)
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
5
35
80
120
200
Deadwood Creek Tributary South
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
7%
70%
23%
0%
0%
2.05
Skewness Coefficient: 0.44
A—125
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)
<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
C ount
Item %
C umulative %
8
4
2
3
8
9
9
7
5
11
11
13
10
0
0
0
0
0
0
0
8%
4%
2%
3%
8%
9%
9%
7%
5%
11%
11%
13%
10%
0%
0%
0%
0%
0%
0%
0%
8%
12%
14%
17%
25%
34%
43%
50%
55%
66%
77%
90%
100%
100%
100%
100%
100%
100%
100%
100%
100%
14
90%
12
Frequency
70%
60%
8
50%
6
Frequency
40%
30%
4
20%
2
Cumulative Frequency
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 - 8
32 -45
45-64
64- 90
8 - 11.3
90 - 128
Bedrock
11.3
16- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
512 - 1024
1024
2048
2048
- 4096
Particle Size Category (mm)
Partic le Siz e Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
8
33
100
150
180
A—126
Cumulative Frequency
80%
10
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
8%
58%
34%
0%
0%
2.01
Skewness Coefficient: 0.25
Deadwood Creek Tributary South
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 %
9
1
2
6
6
3
4
6
5
11
11
10
5
3
7
3
4
0
0
0
9%
1%
2%
6%
6%
3%
4%
6%
5%
11%
11%
10%
5%
3%
7%
3%
4%
0%
0%
0%
9%
10%
13%
19%
25%
28%
32%
39%
44%
55%
67%
77%
82%
85%
93%
96%
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%
12
90%
10
Frequency
8
60%
50%
6
40%
Frequency
4
30%
20%
2
Cumulative Frequency
80%
70%
Cumulative Frequency
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
2-4
4 - 5.7 - 8
32 -45
45-64
64- 90
8 - 11.3
90 - 128
Bedrock
11.3
16- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
512 - 1024
1024
2048
- 2048
- 4096
Particle Size Category (mm)
Partic le Siz e Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
8
60
202
508
813
Deadwood Creek Tributary South
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
9%
46%
30%
15%
0%
2.53
Skewness Coefficient: 0.28
A—127
Culvert Scour Assessment
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
1
1
1
6
7
5
7
11
7
12
16
14
7
1
0
0
0
0
0
2%
1%
1%
1%
6%
7%
5%
7%
11%
7%
12%
16%
14%
7%
1%
0%
0%
0%
0%
0%
2%
3%
4%
5%
11%
18%
23%
31%
42%
49%
61%
78%
92%
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%
80%
Frequency
14
70%
12
60%
10
50%
8
Frequency
6
40%
30%
4
20%
2
10%
Cumulative Frequency
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
Cumulative Frequency
18
2-4
4 - 5.7 - 8
32 -45
45-64
64- 90
8 - 11.3
90 - 128
Bedrock
11.3
16- 16
-22.6
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
512 - 1024
Particle Size Category (mm)
1024
2048
- 2048
- 4096
Partic le Siz e Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
8
14
66
151
214
309
A—128
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
2%
47%
50%
1%
0%
1.57
Skewness Coefficient: 0.29
Deadwood Creek Tributary South
Site Evaluations
Cross Section: Downstream of Culvert – Only Pebble Count
Material
S ize C las s (mm)
C ount
Item %
C umulative %
5
3
3
4
7
7
4
9
13
10
12
19
2
0
1
0
0
0
0
0
5%
3%
3%
4%
7%
7%
4%
9%
13%
10%
12%
19%
2%
0%
1%
0%
0%
0%
0%
0%
5%
8%
11%
15%
22%
29%
33%
42%
56%
66%
78%
97%
99%
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
20
100%
18
90%
16
80%
14
70%
Cumulative Frequency
Frequency
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
12
60%
10
50%
8
Frequency
40%
6
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
16-22.6
11.3-16
5.7-8
8-11.3
<2
4-5.7
<2
0%
2-4
0
Cumulative Frequency
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
1024
2048
- 2048
- 4096
Particle Size Category (mm)
Partic le Siz e Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
2
8
40
102
124
309
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
5%
61%
33%
1%
0%
1.80
Skewness Coefficient: 0.34
*This pebble count was not used in the analysis because the downstream reach was not used as a reference reach
Deadwood Creek Tributary South
A—129