Site Evaluations
Buck Creek
Site Information
Site Location:
Coast Range, Southern Willamette Valley (Deadwood Road)
Year Installed:
2003
Lat/Long:
123°42’11.73”W
44°11’23.80”N
Watershed Area (mi2): 1.54
Stream Slope (ft/ft)1: 0.014
Channel Type:
Pool/Riffle
Bankfull Width (ft): 20 ft
Survey Date:
March 7, 2007
1
Water surface slope extending up to 20 channel widths up and downstream of crossing.
Culvert Information
Culvert Type:
Bottomless arch
Culvert Material: Annular CMP
Culvert Width:
17 ft
Outlet Type:
Projecting
Inlet Type:
Projecting
Culvert Length: 60 ft
Pipe Slope (structure slope): 0.0008
Culvert Bed Slope: 0.015
(First hydraulic control upstream of inlet to first hydraulic control downstream of outlet.)
Culvert width as a percentage of bankfull width: 0.85
Alignment Conditions: Culvert angled towards high bank at downstream end, likely exacerbating
erosion conditions on bank. Possible that meanders were cut off as part of original culvert installation
(older culvert).
Bed Conditions: Angular material in culvert bed; possibly from riprap from inlet that has been
incorporated into culvert bed, or from constructed riprap banks within culvert.
Pipe Condition: Good condition.
Hydrology
Discharge (cfs) for indicated recurrence interval
25% 2-yr
Qbf2
2-year
5-year
10-year
50-year
100-year
100
119
171
208
290
326
2
30
Bankfull flow estimated by matching modeled water surface elevations to field-identified bankfull elevations.
Buck Creek
A—1
Figure 1—Plan view map.
Points represent survey points
Culvert Scour Assessment
A—2
Buck Creek
Site Evaluations
History
The Buck Creek culvert was installed in 2003.
During construction, native material from beneath
the culvert was conserved and placed back
between the footings. The assumed gradation
was the same as the upstream reach. Additional
crushed rock was placed along footings to
prevent scour. There was no sorting or grading
of material during placement, but a shallow
thalweg was formed in the middle third of the
bed. Channel banks were constructed within the
pipe and were composed of sloped crushed rock
riprap (see photo).
For horizontal alignment, lines were drawn on the
site plan, connecting upstream and downstream
banks and mimicking natural meander. The
downstream meander is sharp and no significant
relocation of the channel alignment was
previously done. No structure existed at the site
since it was washed out about 3 years previously.
The new structure was centered in the existing
channel.
With respect to vertical alignment, the upstream
channel was aggraded about 12 inches or less.
Downstream was a scour pool with a maximum
depth of 18 inches. Downstream of the sharp
meander the channel steepened slightly. The
structure was designed to be embedded 1.2
meters below the existing channel and aligned
with the upstream to tailout gradient; however, the
contractor erred and the footings ended up being
placed 2 feet higher than designed. This left an
embedment depth of 24 inches. The footing is
3.5-feet wide, 1-foot thick. The footing stemwall is
4-feet high by 1-foot thick.
There has been no significant maintenance or
management of conditions at the site.
The above information furnished
by Kim Johansen, USFS.
Buck Creek
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 Buck Creek culvert is a tall bottomless arch
that projects from the roadfill. It has prominent
concrete footings exposed along its entire length.
The culvert is made up of a glide in the upstream
portion of the culvert and a steep riffle in the
downstream portion. Coarse angular material
up to large-cobble/small-boulder size is present
in the culvert bed. Two large rootwads, one just
downstream of the inlet and the other at the top
of the steep riffle, have been deposited in the
culvert.
From site observations, it appears that coarse
angular material was placed on the banks at
the inlet and outlet. Sloped crushed-rock riprap
was also placed along the culvert sides within
the culvert (Kim Johansen, USFS, personal
communication). It is likely that the angular
material now making up much of the culvert bed
was recruited from this placed material. There
is now a well-armored steep riffle that makes up
the downstream half of the culvert. This riffle is
steeper and coarser than any riffles observed in
the representative channel segments.
A—3
Culvert Scour Assessment
Upstream of the culvert, extending approximately
250 feet, there is evidence of channel bed
incision characterized by steep, actively eroding
vertical banks. The incision is on the order of 3
feet at the downstream end near the inlet and
tapers off upstream over approximately 250 feet.
The upstream representative reach is located
upstream of this incised area. The reach has
well-defined riffles separated by moderately
deep pools. Sandstone bedrock was present
along upstream portions of the channel bed in
the reach. There is a broad flood-plain terrace
(especially on the right side) that appears to be
active at frequent flood events.
The downstream representative reach is located
around the bend from the scoured left bank
where it abuts the high terrace. The reach is very
sinuous and consists of a series of deep pools
separated by short pool crests/riffles. A low floodplain surface along with high sinuosity indicates
that this reach backwaters during moderately high
flows.
Survey Summary
Eighteen cross sections and a longitudinal profile
were surveyed along Buck Creek in March
2007 to characterize the culvert, an upstream
representative reach, and a downstream
representative reach. Lacking any well-formed
pools through the culvert, the reference cross
sections in the culvert were located on a glide/
riffle and at the top of a steep riffle composed of
coarse angular material. Two additional cross
sections were taken to characterize the inlet and
outlet of the culvert.
Five cross sections were surveyed to characterize
the upstream representative reach; one at the
upstream and downstream ends, two through
riffle channel units and one through a pool. Four
cross sections were surveyed to characterize
the downstream representative reach; one at the
upstream and downstream ends, one through a
pool, and one at the crest of a pool.
A—4
Profile Analysis Segment Summary
The profile analysis resulted in eight profile
segments. The culvert consisted of two profile
segments, each of which extended into culvert
outlet or inlet transition areas. The upstream
culvert segment was compared to two segments
in the upstream channel and one segment in the
downstream channel. The downstream culvert
segment was compared to two segments in the
upstream channel. One segment (E) upstream of
the culvert, where culvert-related channel incision
was observed, was compared to an upstream
reference segment to evaluate the effect of the
culvert on the upstream transition area. See
figure 2, table 1, and table 2.
Observed conditions
Footing scour—There was no observed scour
undermining footings or threatening structure
integrity.
Culvert-bed adjustment—The channel bed shows
flattening through the upstream portion of the
culvert. A third of the way through the culvert the
bed has steepened considerably, resulting in a
channel-bed slope much greater than any found
through the reference channel.
Profile characteristics—The most characteristic
feature of the profile is a steep segment in the
downstream portion of the culvert (figure 2).
There is also an overall segment of steeper
gradient extending from the first hydraulic control
downstream of the outlet to the second hydraulic
control upstream of the inlet. There was also
channel incision noted both upstream of the
inlet (extending 250 feet) and downstream of
the outlet (extending approximately 80 feet). It is
unknown whether this incision is related to this
culvert or a previous installation. Downstream
of the outlet, the channel abuts a high terrace
along the left bank where it causes erosion of
Buck Creek
Site Evaluations
the steep bank during high flows. Erosion of the
terrace has added many large logs to the channel
immediately downstream of the culvert. A scour
pool has formed along the outer left eroding bank.
Based on observations of meander pattern
and valley slope at this site, it is likely that the
channel-migration zone has been truncated by
the culvert and associated roadfill. Straightening
of meanders, which possibly occurred during the
original road construction and culvert installation,
may be contributing to the greater slope through
the crossing. This slope increase may have
contributed to the incision that can be seen in the
channel upstream and downstream of the culvert.
Residual depths—Culvert residual depths ranged
from 0.77 to 1.17 feet and were within the range
of channel conditions (figure 21). This suggests
no significant scour beyond what is found in the
channel outside of the crossing.
Substrate—Culvert bed-material distributions
are generally similar to representative segments.
Culvert substrate is slightly coarser than channel
pebble counts due both to the presence of
larger rocks/boulders within the culvert that
are not present in the channel as well as the
smaller number of finer size classes documented
within the culvert than was documented in the
representative channel pebble counts. The
coarse material in the culvert was placed there
during construction and is evident in the doublepeaked distributions of the culvert pebble counts,
representing native material, which most likely
was transported in and the coarser peak of
placed material. This difference is also evident in
the slightly lower (although still within the range
of the representative channel conditions) sorting
coefficients and the lower skewness values (table
7). Pebble counts are provided at the end of this
summary.
Buck Creek
Predicted conditions
Cross-section characteristics—In general, the
culvert has an impact on the cross-section
characteristics with respect to the upstream and
downstream channel, most notably for the higher
flows. Flow area in the downstream segment of
the culvert (C) is similar to the upstream channel
segment (G) up until the Qbf when the flow area
in the upstream channel becomes slightly greater
(figure 5, figure 12). The upstream segment of
the culvert (D) is similar to the upstream channel
segment (F) for all flows and becomes less than
the downstream channel segment (A) above
the Qbf. Flow area in the upstream transition
segment (E) is similar to the upstream channel
segment (G) up to the Q100 where it is slightly
greater. Wetted perimeter in the downstream
segment of the culvert begins to diverge from,
and becomes less than, the upstream channel
segment (G) by the Qbf (figure 6, figure 13). The
upstream culvert segment (D) is similar to the
upstream channel segment (G) but less than the
downstream channel segment A by the Qbf. The
upstream transition segment (E) has a slightly
higher wetted perimeter below the Q10 and then
becomes similar as the range of values within
the transition segment increases. Hydraulic
radius in the culvert and the upstream transition
segment is similar to that in both the upstream
and downstream channel for most flows (figure
7, figure 14). One exception is the downstream
segment of the culvert (C), which is greater than
the upstream channel segment (G) above the
Q10. Top width within the downstream segment of
the culvert (C) is slightly less than the upstream
channel segment (G) for all flows (figure 8, figure
15). Top width in the upstream segment of the
culvert (D) is similar to the upstream channel
segment (F). Above the Q10, both segments (D)
and (F) have a wide range of values indicating
high variability through these reaches. However,
the median values are relatively close. The
upstream segment of the culvert (D) and the
downstream channel segment (A), however, do
not have similar top widths for lower flows but
A—5
Culvert Scour Assessment
become similar above the Q10 due to the increase
in the range of values in segment D. The top
width of the upstream transition segment (E)
is greater than the upstream channel segment
(G) for the 25 percent Q2 and the Qbf, similar
for the Q10 and similar for the Q50 and Q100. This
variability can also be attributed to the wide
range of values of top width found in segment E.
Maximum depth in the culvert and the upstream
transition segment is similar to that in both the
upstream and downstream channel for most
flows with the exception that culvert segment (D)
has a greater maximum depth than downstream
channel segment (A) for flows above the Q10
(figure 9, figure 16). Width- to-depth ratio in the
culvert is similar to the upstream channel with
the exception of the downstream segment of the
culvert which remains the same above the Qbf,
while upstream channel segment (G) increases
(figure 17). However, the width-to-depth ratio
in the culvert compared to the downstream
channel segment (A) is less, with the exception of
segment D which becomes similar to segment A
as the range of values becomes large above the
Q10.
Shear stress—Shear stress in the culvert is
similar to the upstream and downstream channel
for the range of flows (figure 19). However, the
downstream segment of the culvert has higher
median values than the upstream channel
segment (G). The difference between the two
culvert segments can be attributed to the change
in slope. This transition between segments C and
D experiences the highest shear stress values
in the entire reach (figure 10). The upstream
transition segment E’s shear stress is similar to,
if not slightly less than, the upstream channel
segment G for all flows, a phenomenon related to
backwater effects of the culvert.
Excess shear—The excess shear analysis
shows that the culvert has greater potential for
bed mobilization than the upstream channel at
all flows and similar potential to the downstream
channel for flows above the Qbf (figure 20). The
A—6
excess shear analysis shows that the DS channel
has a greater potential for bed mobilization at
the 25 percent Q2 than does the culvert having a
value above the threshold value of “1,” dropping
back to similar values as found in the culvert.
While this phenomenon may be real, it may most
likely be attributed to model instability.
Velocity –Velocity in the upstream culvert
segment (D) is similar to the upstream
representative channel segment (F) but higher
than the downstream representative segment
(A) at the Q10 and above (figure 11, figure 18).
Velocity in the downstream culvert segment (C) is
higher than the upstream representative segment
(G) at the Q2 and above. These higher culvert
velocities correspond to the flow contraction
(reduction in flow area) caused by the culvert.
The upstream transition segment (E) is similar, if
not slightly less than, the upstream representative
channel segment (G).
Scour summary
While the culvert shows no significant bed scour,
evidence of bed adjustment exist. The convex
channel profile through the crossing indicates
heavy incision through the downstream portion
of the culvert and the downstream channel with
minor aggradation through the upstream portion.
Based on observations of meander pattern and
valley slope at this site, it is likely that the channel
migration zone has been truncated by the culvert
and associated roadfill. Such a change in channel
planform, i.e., a shorter channel length, would
likely result in a greater bed slope. As the channel
has eroded away into the high terrace forming a
deep scour pool, the downstream segment of the
culvert has steepened into a high-gradient riffle
as the larger placed rock serves to control grade.
The drop in grade creates a backwater condition
through the upstream culvert during high flows
resulting in minor aggradation. Additionally, 250
feet of channel upstream of the crossing shows
evidence of incision.
Buck Creek
Site Evaluations
Conditions indicate a low risk for future scour in
the culvert. Further erosion of the channel bed
through the culvert is possible according to the
excess shear analysis as the bed continues to
adjust to the altered channel planform. In the
future the upstream channel may show significant
channel changes as it adjusts to the incision.
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 in the
culvert segments are both within the range of
those in the channel cross sections (table 4).
Depth distribution—There is less channel margin
habitat in the upstream culvert compared to
the channel at the 25 percent Q2 but similar
channel margin habitat in the downstream culvert
compared to the channel (table 5).
Habitat units—The habitat-unit composition
shows great variation between the culvert and
the upstream and downstream representative
channels (table 6). Both the culvert and
upstream channel have similar percentages of
riffle; however the remainder of the units in the
upstream channel is pool while the remainder
of the channel within the culvert is composed of
glide. The downstream channel consists of mostly
of pool habitat (82 percent) with only short riffles/
pool crests separating each pool.
Residual depths—Culvert residual depths are
within the range of channel conditions (figure 21).
Bed material—Bed-material distributions are
similar in the culvert compared to the channel
(see pebble-count data provided at end of
this site summary). The culvert has a similar
Buck Creek
percentage of gravels as the upstream channel
but less than the downstream channel. The
size and frequency of the large particles in the
culvert are greater than both the upstream and
the downstream channel. This partly reflects the
gradient transition through the crossing but also
reflects the large rocks that were placed during
construction. Culvert bed material sorting values
are relatively low indicating a narrower range of
particle sizes than the channel, yet are all within
the range found in the stream channel (table 7).
The bed material skewness value in the upstream
XS in the culvert is less than any skewness
values in the channel. The low value indicates a
nearly normal (symmetrical) distribution, which is
due to a similar number of large particles (greater
than 256) and small particles (less than 22.6).
Large woody debris—There was one large log
present in the upstream portion of the culvert
(table 8). The downstream channel had high
LWD abundance, primarily as a result of a LWD
jam just downstream of the culvert outlet. LWD
created habitat complexity but was not a primary
pool-forming feature in the natural channel.
AOP summary
Measurements and observations suggest that the
Buck Creek culvert has similar conditions to the
natural channel with respect to aquatic organism
passage (AOP). Cross-section complexity in the
culvert is within the range of that found in the
channel. Culvert residual depths and vertical
sinuosity are also similar to the channel. Potential
passage issues may result from a lack of pool
habitat available through the crossing and a
deficit of channel margin habitat especially in
the upstream portion of the culvert. The steep
riffle in the downstream portion of the culvert is
steeper and coarser than any riffles observed in
the reference segments; however, fish passage
appears to be suitable at the flow level observed
during the survey.
A—7
Culvert Scour Assessment
Bed material composition is similar between the
culvert and the channel segments, with only slight
differences that can be explained by the gradient
transition through the downstream segment and
the placement of rock during construction. These
similar bed compositions suggest that AOP is not
impaired by the characteristics of the culvert bed
material.
Design Considerations
Despite moderate bed adjustments, this
design has functioned relatively well. The likely
adjustment to the creek’s channel planform has
resulted in bed adjustments through the crossing
and in the downstream channel. Placed material
serves as grade control, essentially preventing
a headcut and further incision from occurring.
Additional erosion of the high terrace on the left
bank immediately downstream of the culvert
will continue to deliver wood and sediment to
the channel. Exposed footings do not appear to
be threatened by these adjustments. Two logs
documented within the crossing at the time of the
survey indicate the potential for passage of wood
through the crossing at high flows which could
cause structural problems in the future.
Hydraulic modeling indicates that flows up to the
Q100 are able to pass through the culvert with
almost 7 feet of clearance at the inlet between the
modeled water surface and the crown indicating
that the pipe is more than large enough to pass
flows.
A—8
Buck Creek
498
500
502
900
XS 1
800
XS 2:
Pebble count
(pool)
A
700
XS 3:
Pebble count
(riffle)
Representative Channel
E
U ps trea m T ra n s itio n
C u lv ert S eg men t
D
D
C
C
Table 1—Segment comparisons
XS 4
G
XS 6
600
Log Jam
XS 5
B
Scour at toe of high
bank on left
R epres en ta tiv e
C h a n n el S eg men t
F
A
E
G
Figure 2—Buck Creek longitudinal profile.
490
492
494
Relative elevation (feet)
496
Relative Elevation (ft)
)
Buck Creek
504
506
508
510
XS 10
XS 11
XS 9:
Pebble count
(glide)
D
400
XS 12
5.8%
% D ifferen c e in
G ra d ien t
40.8%
49.8%
37.9%
41.5%
E
XS 13
300
F
S egm ent
A
B
C
D
E
F
G
H
Channel incision
D is ta nc e a long bed (feet)
500
XS 8:
Pebble count
(step)
XS 7
C
C ulvert
200
XS 15:
Pebble count
(pool)
S egm ent
L ength (ft)
255
47
69
76
84
160
92
68
XS 14:
Pebble count
(riffle)
G
100
XS 16:
Pebble count
(riffle)
H
XS 17
S egm ent G ra dient
0.009
0.000
0.025
0.005
0.016
0.008
0.015
0.009
Representative Channel
0
Site Evaluations
A—9
n
o
i
t
a
v
e
l
E
)
t
f
(
A—10
0.0612-0.00.0691
0.0607-0.0727
0.0624-0.0712
0.0641-0.0705
0.0638-0.0705
0.0631-0.0654
A
C
D
E
F
G
2
2
2
3
3
4
12
16
10
8
6
27
SegmentRange of Manning's n values1 # of measured XSs# of interpolated XSs
1
*
5
7
490 . 1
0
2
6
.
2
*
8
.
2
*
*
6
3
6
3
* *
* *
*
6
3
* 5 5
2 6
5
*
6
3
5 2 7
9 1 3 6 8 4
5
6 5 8 5 2 . .
. . . . . .
.
. . . . . 0 0
2 3 3 3 3 4 5 5 6 6 7 7 8 9 1 1
200
400
Stations with decimal values are
interpolated cross sections placed
along the surveyed profile.
Figure 3—HEC-RAS profile
Elevation (ft)
495
500
505
510
*
5
7
.
1
1
*
1
.
2
1
*
4
.
2
1
*
5
7
8
.
2
1
*
6
0
.
3
1
*
8
1
.
3
1
*
3
*
3
5
3
3 4 6 7
. . . .
3 3 3 3
1 1 1 1
600
Main Channel Dis tance (ft)
*
5
2
.
1
1
*
5
2
6
.
2
1
*
6
6
6
*
8
5
4
.
.
.
3 4 4 5 5
1 1 1 1 1
*
3
3
* 8
8 0
. .
5 6
1 1
*
5
2
.
6
1
*
6
6
1
4
.
6
1
*
3
3 *
8 5
5 7
. .
6 6
1 1
800
*
6
6
1
9
.
6
1
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.
Table 2—Summary of segments used for comparisons
1000
Ground
W S 30 c fs
W S Qbf
W S Q10
W S Q50
W S Q100
L e ge nd
Culvert Scour Assessment
Buck Creek
Buck Creek
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
)
t
f
(
498
-40
500
-20
0
20
.07
80
.0669
120
60
.07
Station (ft)
40
.
0
6
3
1
RS = 15
Station (ft)
100
80
140
.07
100
120
160
140
180
Bank St a
Ground
WS 30 c fs
n
o
L e ge nd
i
t
WS Q100
a
WS Q50
v
e
WS Q10
l
WS Qbf
E
)
t
f
(
Bank St a
Ground
WS 30 c fs
Elevation (ft)
498
500
502
504
506
508
510
0
500
-20
502
504
506
508
510
512
20
0
.07
40
20
.07
60
80
Station (ft)
60
.0645
RS = 14
Station (ft)
40
.064
RS = 16
100
80
.07
.07
120
100
WS Qbf
WS Q10
WS Q50
B a n k S ta
L e ve e
G ro u n d
W S 3 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 30 c fs
140
120
L e ge nd
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)
502
504
60
.07
n
o
L e geind
t
WS Q100
a
v
WS Q50
e
WS Q10
l
E
WS Qbf
Elevation (ft)
506
508
510
500
40
502
504
506
508
510
512
RS = 17
)
t
f
(
Site Evaluations
A—11
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—12
496
0
20
-20
40
0
40
80
Station (ft)
60
.0644
RS = 11
Station (ft)
20
.0705
80
100
.07
60
.07
120
100
L e ge n d
B a n k S ta
In e ff
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
140
120
Bank St a
Ground
WS 30 c fs
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)
496
498
500
502
504
506
508
0
496
20
498
500
502
504
506
508
20
.0624
40
.07
.0624
40
60
Station (ft)
60
RS = 10
80
100
Station (ft)
80
.0641
RS = 12
100
.0624
120
.07
120
140
L e ge n d
B a n k S ta
In e ff
L e ve e
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
140
160
Bank St a
Ground
WS 30 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. (continued)
Elevation (ft)
498
500
502
.07
-40
.
0
7
n
o
i
t
a
v
e
l
E
Elevation (ft)
504
506
508
498
-60
500
502
504
506
508
510
RS = 13
)
t
f
(
Culvert Scour Assessment
Buck Creek
)
t
f
(
Buck Creek
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
494
-40
-20
0
-20
. .
0 0
7 4
5
40
Station (ft)
20
.
0
4
5
RS = 7
.
0
6
0
7
.06
20
Station (ft)
0
60
40
80
60
L e ge n d
B a n k S ta
In e ff
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
100
80
Bank St a
Ground
WS 30 c fs
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)
494
-40
496
498
500
502
504
506
496
-60
498
500
502
504
506
508
-20
-40
0
. .0641
0
7
5
-20
20
40
Station (ft)
20
RS = 6
Station (ft)
0
. .0727 .
0
0
1
1
3
3
RS = 8
.075
60
40
80
60
L e ge n d
B a n k S ta
In e ff
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
100
80
Bank St a
Ground
WS 30 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. (continued)
Elevation (ft)
496
498
500
-40
. .0698 .
0
0
1
1
3
3
n
o
i
t
a
v
e
l
E
Elevation (ft)
502
504
506
496
-60
498
500
502
504
506
508
RS = 9
)
t
f
(
Site Evaluations
A—13
A—14
Elevation (ft)
n
o
i
t
a
v
e
l
E
)
t
f
(
n
o
i
t
a
v
e
l
E
)
t
f
(
494
-20
0
.
0
7
5
20
.0666
0
40
o
i
t
a
v
e
l
E
Stationn(ft)
40
)
t
f
( 60
.075
RS = 3
Station (ft)
20
.0626
Elevation (ft)
492
-40
494
496
498
500
502
-20
100
80
504
80
60
.075
0
L e ge n d
.075
B a n k S ta
L e ve e
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
120
100
B a n k S ta
In e ff
G ro u n d
W S 3 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
60
490
-40
492
494
496
498
500
502
494
-20
.075
40
Station (ft)
20
.
0
6
2
9
RS = 1
n
o
i
t
a
v
e
l
E
)
t
f
(
496
498
500
502
504
506
Elevation (ft)
-20
80
0
.075
100
20
Bank St a
Gr ound
WS 30 c fs
WS Qbf
WS Q10
WS Q50
WS Q100
Station (ft)
20
.0631
RS = 2
40
.075
60
Station (ft)
40
.075
L e ge nd
0
.0639
RS = 4
60
.075
80
80
100
L e ge n d
B a n k S ta
L e ve e
G ro u n d
W S 3 0 c fs
W S Qb f
W S Q1 0
W S Q5 0
W S Q1 0 0
100
120
Bank St a
Ground
WS 30 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. (continued)
Elevation (ft)
496
498
500
-20
.
0
7
5
n
o
i
t
a
v
e
l
E
Elevation (ft)
502
504
506
494
-40
496
498
500
502
504
506
RS = 5
)
t
f
(
Culvert Scour Assessment
Buck Creek
Flow Area (sq ft)
Buck Creek
.
P
.
W
l
a
t
o
T
)
t
f
(
w
o
l
F
a
e
r
A
q
s
(
)
t
f
0
100
200
300
600
F
700
G
G
H
900
Flow Area Q100
Legend
0
100
200
300
W.P. Total (ft)
A—15
Figure 6—Wetted perimeter.
0
20
40
60
80
500
Main Channel Distance (ft)
400
E
600
F
700
800
Flow
900
W.P. Total Q100
Legend
W.P. Total 30 cfs
W.P. Total Qbf
W.P. Total Q10
Culvert
D
Flow Area 30 cfs
Flow Area Qbf
100
B
Main Channel Distance (ft)
800
Flow
H
W.P. Total Q50
A
C
500
E
120
140
160
Figure 5—Flow area (total) profile plot.
0
20
40
60
80
400
D
Flow Area Q10
Culvert
C
100
B
Flow Area Q50
A
120
140
160
Site Evaluations
A—16
Hydr Radius (ft)
p
o
T
h
t
d
i
W
)
t
f
(
r
d
y
H
s
u
i
d
a
R
)
t
f
(
0
100
A
200
0
100
A
Figure 8—Top width.
0
20
40
60
80
100
120
140
200
Figure 7—Hydraulic radius.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
B
B
300
300
500
E
500
E
Main Channel Distance (ft)
400
D
Main Channel Distance (ft)
Culvert
C
D
400
Culvert
C
600
F
600
F
700
700
G
G
800
Flow
800
Flow
H
H
900
900
Top Width 30 cfs
Top Width Qbf
Top Width Q10
Top Width Q50
Top Width Q100
Legend
Hydr Radius 30 cfs
Hydr Radius Qbf
Hydr Radius Q10
Hydr Radius Q100
Hydr Radius Q50
Legend
Culvert Scour Assessment
Top Width (ft)
Buck Creek
Max Channel Depth (ft)
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
)
t
f
(
0
100
A
200
0
100
200
300
Buck Creek
Shear Chan (lb/sq ft)
A—17
Figure 10—Shear stress (channel) profile.
0
1
2
3
4
500
E
Main Channel Distance (ft)
400
D
600
600
F
F
700
700
G
G
800
Flow
800
Flow
H
H
900
900
Shear Chan Q100
Legend
Max Chl Dpth 30 cfs
Max Chl Dpth Qbf
Max Chl Dpth Q10
Max Chl Dpth Q50
Max Chl Dpth Q100
Legend
Shear Chan 30 cfs
Shear Chan Qbf
Shear Chan Q10
Culvert
C
Main Channel Distance (ft)
500
E
5
B
D
400
Culvert
C
Shear Chan Q50
A
300
B
6
7
8
Figure 9—Maximum depth.
0
1
2
3
4
5
6
Site Evaluations
A—18
l
e
V
l
n
h
C
)
s
/
t
f
(
0
100
A
200
B
300
Figure 11—Velocity (channel) profile plot.
0
1
2
3
4
5
6
7
8
9
D
500
E
Main Channel Distance (ft)
400
Culvert
C
600
F
700
G
800
Flow
H
900
Vel Chnl 30 cfs
Vel Chnl Qbf
Vel Chnl Q10
Vel Chnl Q50
Vel Chnl Q100
Legend
Culvert Scour Assessment
Vel Chnl (ft/s)
Buck Creek
50
A
G
G
E (us trans)
D (culv)
25% Q2
E (us trans)
C (culv)
D (culv)
F
F
C (culv)
Figure 12—Flow area (total).
0
Flow40
Area (ft2)
80
120
160
A
G
G
F
E (us trans)
E (us trans)
D (culv)
Qbf
F
50%
of the values
C (culv)
D (culv)
100%
of the values
A
C (culv)
C (culv)
G
G
F
E (us trans)
E (us trans)
10
F
M inim um value
A
25 th percentile
Median (aka 50
C (culv)
D (culv)
D (culv)
A
75 th percentile
th
50
F
G
G
F
E (us trans)
C (culv)
D (culv)
percentile)
C (culv)
Maxim um value
D (culv)
Box Plot Explanation
E (us trans)
A
Buck Creek
Flow Area (ft2)
A
A
G
G
F
E (us trans)
E (us trans)
D (culv)
100
C (culv)
D (culv)
F
Site Evaluations
A—19
C (culv)
A
A
E (us trans)
C (culv)
A
G
25% Q2
E (us trans)
C (culv)
D (culv)
F
Figure 14—Hydraulic radius.
0
Hydraulic Radius (ft)
1
2
3
4
E (us trans)
Figure 13—Wetted perimeter.
25% Q2
E (us trans)
C (culv)
D (culv)
D (culv)
D (culv)
G
A
A
A
Qbf
F
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
Qbf
C (culv)
D (culv)
C (culv)
C (culv)
F
F
E (us trans)
E (us trans)
G
G
D (culv)
D (culv)
F
F
F
A
A
A
A
A
A
10
F
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
10
C (culv)
D (culv)
C (culv)
C (culv)
G
G
E (us trans)
E (us trans)
0
D (culv)
D (culv)
F
F
40
A
A
A
A
Wetted Perimeter (ft)
50
F
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
50
C (culv)
D (culv)
C (culv)
C (culv)
80
D (culv)
D (culv)
G
G
E (us trans)
E (us trans)
120
A
A
A
A
A
A
Hydraulic Radius (ft)
C (culv)
100
F
G
G
F
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
100
C (culv)
D (culv)
C (culv)
C (culv)
F
F
D (culv)
D (culv)
G
G
E (us trans)
E (us trans)
A—20
F
Wetted Perimeter (ft)
G
160
Culvert Scour Assessment
Buck Creek
E (us trans)
D (culv)
25% Q2
C (culv)
A
G
25% Q2
E (us trans)
C (culv)
D (culv)
F
Figure 16—Maximum depth.
0
Maximum Depth (ft)
2
4
6
E (us trans)
Figure 15—Top width.
G
E (us trans)
C (culv)
D (culv)
F
A
A
A
Qbf
G
F
G
E (us trans)
C (culv)
D (culv)
Qbf
F
E (us trans)
C (culv)
D (culv)
C (culv)
C (culv)
F
F
E (us trans)
E (us trans)
G
G
D (culv)
D (culv)
F
F
A
A
A
A
A
A
0
10
F
G
G
E (us trans)
C (culv)
D (culv)
10
F
E (us trans)
C (culv)
D (culv)
C (culv)
C (culv)
G
G
E (us trans)
E (us trans)
40
D (culv)
D (culv)
F
F
Top Width (ft)
A
A
80
A
A
C (culv)
C (culv)
120
50
F
G
G
E (us trans)
C (culv)
D (culv)
50
F
E (us trans)
C (culv)
D (culv)
D (culv)
D (culv)
G
G
E (us trans)
E (us trans)
160
A
A
A
A
Maximum Depth (ft)
C (culv)
A
A
100
F
G
G
E (us trans)
C (culv)
D (culv)
100
F
G
E (us trans)
C (culv)
D (culv)
C (culv)
C (culv)
F
F
E (us trans)
E (us trans)
G
G
D (culv)
D (culv)
F
F
Buck Creek
G
Top Width (ft)
D (culv)
Site Evaluations
A—21
E (us trans)
E (us trans)
F
C (culv)
A
F
G
25% Q2
E (us trans)
C (culv)
D (culv)
C (culv)
Figure 18—Velocity (channel).
0
2
D (culv)
A
Qbf
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
Qbf
F
A
A
A
A
A
Velocity (ft/sec)
4
6
8
10
E (us trans)
Figure 17—Width-to-depth ratio.
F
C (culv)
D (culv)
C (culv)
C (culv)
G
G
D (culv)
D (culv)
D (culv)
25% Q2
A
A
E (us trans)
E (us trans)
F
F
C (culv)
D (culv)
A
10
F
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
10
C (culv)
D (culv)
C (culv)
C (culv)
G
G
E (us trans)
E (us trans)
G
D (culv)
D (culv)
F
F
F
A
A
C (culv)
50
F
G
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
50
C (culv)
D (culv)
C (culv)
A
D (culv)
D (culv)
G
G
E (us trans)
E (us trans)
0
A
A
F
F
40
A
A
A
A
80
100
F
G
G
F
G
E (us trans)
F
E (us trans)
C (culv)
D (culv)
100
C (culv)
D (culv)
C (culv)
C (culv)
Width-to-depth Ratio
Velocity (ft/sec)
A
D (culv)
D (culv)
G
G
E (us trans)
E (us trans)
A—22
F
Width-to-depth Ratio
G
120
Culvert Scour Assessment
Buck Creek
A
E (us trans)
G
G
F
25% Q2
E (us trans)
C (culv)
D (culv)
F
A
A
Excess Shear (Applied/tcrit)
0
50
100
150
200
Dis charge (cfs )
E (us trans)
D (culv)
250
Qbf
F
300
A
A
350
G
G
E (us trans)
C (culv)
D (culv)
F
E (us trans)
D (culv)
C (culv)
DS Channel (US pebble count) - riffle
Culvert (DS pebble count) - step
Culvert (US pebble count) - glide
US Channel (DS pebble count) - riffle
US Channel (US pebble count) - riffle
10
Figure 20—Excess shear stress.
G
G
E (us trans)
C (culv)
D (culv)
F
F
C (culv)
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
1
Excess Shear (Applied / tcrit)
2
3
4
5
Figure 19—Shear stress (channel).
0
A
Shear Stress (lbs/ft2)
C (culv)
Shear Stress (lbs/ft2)
D (culv)
Buck Creek
2
4
6
8
A
D (culv)
50
G
G
F
E (us trans)
E (us trans)
C (culv)
D (culv)
F
A
D (culv)
100
G
G
F
E (us trans)
E (us trans)
C (culv)
D (culv)
F
Site Evaluations
A—23
C (culv)
A
C (culv)
A
Culvert Scour Assessment
Table 3—Sum of squared height difference
Reach
XS LocationUnit type
Culvert
Sum of squared height difference
Within range of
channel conditions?
US
Glide
0.07
Yes
DS
Step
0.04
Yes
US
Riffle
0.03
Middle
Pool
0.09
Upstream
DS
Riffle
0.03
Downstream
US
Riffle
0.01
DS
Pool
0.04
Table 4—Vertical sinuosity
Segment
LocationVertical Sinuosity (ft/ft)
A
DS channel
1.001
B
DS channel
1.001
C
Culvert
1.003
D
Culvert
1.001
E
US transition
1.002
F
US channel
1.001
G
US channel
1.001
H
US channel
1.005
Table 5—Depth distribution
Reach
XS Location
25% Q2
Culvert
Within range of
channel conditions?
US
1
No
DS
5
Yes
US
2
Middle
2
DS
3
US
2
DS
11
Upstream
Downstream
A—24
Buck Creek
Site Evaluations
Table 6­—Habitat unit composition
Percent of surface area
Reach
Pool Glide
Riffle
Step
Culvert
0%
65%
35%
0%
Upstream Channel
67%
0%
31%
2%
Downstream Channel
82%
0%
18%
0%
2.0

1.8
Residual depth (ft)
1.6

1.4


1.2


1.0

0.8




Residual
depth (ft)
0.6


0.4
0.2
0.0
Segment A
Segment B: Segment C: DS Transition
Culvert
Figure 21—Residual Segment
depths A
Segment D: Segmen E: Segment F
Culvert
US Transition
Culvert
Segment
B: Segment C:
DS Transition
Culvert
Segment D:
Segment G
Segment F
Segment
E:
US Transition
Segment H
Segment G
Segment H
Table 7— Bed material sorting and skewness
Reach
XSUnit
Sorting
Location
Type
Culvert
Within range Skewness Within range
of channel
of channel
conditions?
conditions?
US
Glide
1.82
Yes
0.09
No
DS
Step
1.90
Yes
0.30
No
US
Riffle
2.40
0.47
Middle
Pool
2.68
0.36
Upstream
DS
Riffle
2.09
0.52
Downstream
US
Riffle
1.73
0.40
DS
Pool
2.37
0.52
Buck Creek
A—25
Culvert Scour Assessment
Table 8—Large woody debris
Reach
Pieces/
Channel Width
Culvert
0.66
Upstream
0.66
Downstream
2.1
Terminology:
US = Upstream
DS = Downstream
RR = Reference reach
XS = Cross section
View upstream through culvert.
View downstream through culvert.
Downstream reference reach—upstream pebble
Downstream reference reach—downstream pebble
count, riffle. count, pool.
A—26
Buck Creek
Site Evaluations
Upstream reference reach—upstream pebble count, riffle.
Upstream reference reach—middle pebble
count, pool.
Upstream reference reach—downstream pebble count, riffle.
Incision induced bank erosion in channel
upstream of culvert.
Buck Creek
A—27
Culvert Scour Assessment
Cross section: Upstream Reference Reach—Upstream Pebble Count
Material
S ize R ange (mm)
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
C ount
Item %
C umulative %
13
4
0
2
2
4
7
7
10
12
13
9
13
2
1
0
0
0
0
0
13%
4%
0%
2%
2%
4%
7%
7%
10%
12%
13%
9%
13%
2%
1%
0%
0%
0%
0%
0%
13%
17%
17%
19%
21%
25%
32%
39%
49%
62%
75%
84%
97%
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
> 4096
14
100%
90%
12
Frequency
70%
60%
8
50%
6
40%
Frequency
4
30%
20%
2
10%
Cumulative Frequency
>4096
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
90-128
128-180
64-90
45-64
32-45
22.6-32
11.3-16
16-22.6
5.7-8
8-11.3
<2
4-5.7
<2
0%
2-4
0
Cumulative Frequency
80%
10
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)
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
4
47
127
171
280
A—28
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
13%
48%
37%
1%
0%
2.40
Skewness Coefficient: 0.47
Buck Creek
Site Evaluations
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
C ount
Item %
C umulative %
31
7
2
2
6
9
5
11
9
8
20
11
7
0
0
0
0
0
0
0
24%
5%
2%
2%
5%
7%
4%
9%
7%
6%
16%
9%
5%
0%
0%
0%
0%
0%
0%
0%
24%
30%
31%
33%
38%
45%
48%
57%
64%
70%
86%
95%
100%
100%
100%
100%
100%
100%
100%
100%
35
100%
90%
30
80%
Frequency
25
70%
60%
20
50%
15
Frequency
40%
30%
10
20%
5
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
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 - 8
32 -45
45-64
64- 90
8 - 11.3
Bedrock
90 - 128
11.3
16- -22.6
16
22.6- 32
128180
- 180
256
- 256
362
- 362
- 512
512 - 1024
1024
2048
- 2048
- 4096
Particle Size Category (mm)
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
1
24
88
128
170
Buck Creek
Cumulative Frequency
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
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
24%
46%
30%
0%
0%
2.68
Skewness Coefficient: 0.36
A—29
Culvert Scour Assessment
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
2
0
3
7
4
5
6
9
9
23
11
15
5
2
0
0
0
0
0
8%
2%
0%
3%
6%
4%
5%
5%
8%
8%
21%
10%
14%
5%
2%
0%
0%
0%
0%
0%
8%
10%
10%
13%
19%
23%
27%
33%
41%
49%
70%
80%
94%
98%
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
25
100%
90%
20
Frequency
70%
15
60%
50%
10
Frequency
40%
30%
20%
5
Cumulative Frequency
80%
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
16-22.6
11.3-16
5.7-8
2-4
4 - 5.7
5.7 - 8
32 -45
45-64
64- 90
8 - 11.3
Bedrock
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
10
66
130
210
280
A—30
8-11.3
<2
4-5.7
<2
0%
2-4
0
Sorting Coefficient:
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
8%
41%
49%
2%
0%
2.09
Skewness Coefficient:0.52
Buck Creek
Site Evaluations
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 %
4
0
1
4
2
2
8
12
12
4
8
11
12
5
9
4
3
0
0
0
4%
0%
1%
4%
2%
2%
8%
12%
12%
4%
8%
11%
12%
5%
9%
4%
3%
0%
0%
0%
4%
4%
5%
9%
11%
13%
21%
33%
45%
49%
56%
67%
79%
84%
93%
97%
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%
80%
10
70%
8
60%
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
Bedrock
90 - 128
11.3
16- -16
22.6
22.6- 32
180
- 180
256
- 256
362
- 362
- 512
Particle Size Category 128
(mm)
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
6
20
70
240
406
610
Buck Creek
Cumulative Frequency
Frequency
12
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
4%
45%
36%
16%
0%
Sorting Coefficient:
1.82
Skewness Coefficient: 0.09
A—31
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
<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 %
4
3
1
2
3
4
3
7
7
15
12
9
10
15
8
3
1
4%
3%
1%
2%
3%
4%
3%
7%
7%
14%
11%
8%
9%
14%
7%
3%
1%
0%
0%
0%
4%
7%
7%
9%
12%
16%
19%
25%
32%
46%
57%
65%
75%
89%
96%
99%
100%
100%
100%
100%
16
100%
14
90%
80%
Frequency
12
70%
10
60%
8
50%
40%
Frequency
6
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
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 - 8
32 -45
45-64
64- 90
8 - 11.3
Bedrock
90 - 128
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
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
3
18
80
210
337
610
A—32
Cumulative Frequency
S ize C las s (mm)
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
4%
42%
43%
11%
0%
Sorting Coefficient:
1.90
Skewness Coefficient: 0.30
Buck Creek
Site Evaluations
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 %
11
0
0
4
5
8
6
13
17
14
16
4
4
0
0
0
0
0
0
0
11%
0%
0%
4%
5%
8%
6%
13%
17%
14%
16%
4%
4%
0%
0%
0%
0%
0%
0%
0%
11%
11%
11%
15%
20%
27%
33%
46%
63%
76%
92%
96%
100%
100%
100%
100%
100%
100%
100%
100%
18
100%
16
90%
14
80%
70%
Frequency
12
60%
10
50%
8
Frequency
6
40%
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
4-5.7
<2
<2
2-4
4 - 5.7 - 8
32 -45
45-64
64- 90
8 - 11.3
Bedrock
90 - 128
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
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
10
35
70
110
140
Buck Creek
Cumulative Frequency
0%
2-4
0
Cumulative Frequency
Cross section: Downstream Reference Reach—Upstream Pebble Count
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
11%
66%
24%
0%
0%
Sorting Coefficient:
1.73
Skewness Coefficient:0.40
A—33
Culvert Scour Assessment
Cross section: Downstream Reference Reach—Downstream Pebble Count
Material
S ize C las s (mm)
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
C ount
Item %
C umulative %
23
5
2
2
2
9
12
11
19
17
7
1
1
0
0
0
0
0
0
21%
5%
2%
2%
2%
8%
11%
10%
17%
15%
6%
1%
1%
0%
0%
0%
0%
0%
0%
0%
21%
25%
27%
29%
31%
39%
50%
59%
77%
92%
98%
99%
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
25
100%
90%
20
70%
15
Frequency
60%
50%
10
Frequency
40%
30%
5
20%
Cumulative Frequency
80%
Cumulative Frequency
10%
Bedrock
2048-4096
1024-2048
362-512
512-1024
256-362
180-256
90-128
128-180
64-90
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
Bedrock
90 - 128
11.316
- 16
- 22.6
22.6 - 32
128 180
- 180
256
- 256
362
- 362- 512
512 - 1024
1024
2048
2048
- 4096
Particle Size Category (mm)
Particle Size Category (mm)
S ize C las s
S ize perc ent finer
than (mm)
D5
D16
D50
D84
D95
D100
1
1
23
55
70
130
A—34
8-11.3
<2
4-5.7
<2
0%
2-4
0
Material
P erc ent C ompos ition
Sand
Gravel
Cobble
Boulder
Bedrock
21%
71%
8%
0%
0%
Sorting Coefficient:
2.37
Skewness Coefficient:0.52
Buck Creek