20170537 Ver 1_Appendix C_20170517

Appendix C
Mitigation Work Plan Data and Analysis
Hannah Bridge Morphological Parameters
Existing Cross Section and Profile Charts
Hannah Bridge Stable Channel Hydraulic Design Output

Hannah Bridge Morphological Parameters
Existing' I Design
1 Bankfull stage was estimated using NC Regional Curve equations and existing conditions data
2 NC Regional Curve equations source: Doll et al. (2003;
3 NC Regional Curve equations source: Sweet and Geratz (2003
HBI
HBI
H62
H62
H1132
H1133
H63
HB3
HB3
HB4
HF1
HF1
HF2
TH2
TH3
TH3
EA
EA
H131, H133
Feature
Shallow
Pool
Shallow
Pool
Shallow
Shallow
Pool
Shallow
Pool
Shallow
Run
Run
Shallow
Shallow
Shallow
Run
Shallow
Run
Shallow I
Pool
Drainage Area ac
667
752
816
894
78
78
13
24
24
10
667-816
Drainage Area (mi2)
1.04
1.18
1.28
1.40
0.12
0.12
0.02
0.04
0.04
0.02
1.0-1.3
NC Regional Curve Discharge cfs z
17.1
18.6
19.7
21.1
3.6
3.6
1.0
1.6
1.6
0.8
17-20
NC Regional Curve Discharge cfs 3
9.1
9.9
10.6
11.3
1.8
1.8
0.5
0.7
0.7
0.4
9-11
Design/Calculated Discharge cfs
20-25
29-31
23-37
1 18-24
4-5
1 1.5-4
4-5
1
2-4
2-3
30-32
Dimension
BF Width ft
12.1
14.0
12.2
11.4
10.8
18.4
21.8
11.3
7.9
23.8
8.2
6.1
4.5
5.0
5.3
2.2
2.6
5.1
12.2
12
Floodprone Width ft
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
>50
7
10
7
5
4
7
>50
>50
BF Cross Sectional Area ftZ
12.2
13.4
15.8
16.5
14.7
16.6
20.6
13.1
13.2
19.4
3.4
3.6
1.5
1.8
1.6
2.1
1.0
1.9
15.4
17.1
BF Mean Depth ft
1.0
1.0
1.3
1.4
1.4
0.9
0.9
1.2
1.7
0.8
0.4
0.6
0.3
0.4
0.3
0.9
0.4
0.4
1.3
1.4
BF Max Depth ft
2.3
2.7
2.0
2.5
1.8
1.7
2.6
2.3
2.8
1.8
0.8
0.7
0.5
0.8
0.6
1.3
0.6
0.6
1.6
2.2
Width/Depth Ratio
12.1
14.6
9.4
7.9
7.9
20.3
23.0
9.7
4.7
29.3
19.5
10.5
13.4
13.7
17.2
2.3
6.8
13.2
9.7
8.4
Entrenchment Ratio
>2.2
1
>2.2
1 >2.2
1 >2.2
1 >2.2 1
>2.2
>2.2
>2.2
>2.2
1 >2.2
>2.2
>2.2
1.4
1.9
1.2
1
2.3
1.8
1.3
>2.2>2.2
Wetted Perimeter ft
14.4
1
16.2
1 13.6
1 13.5
1 12.1 1
20.0
1 23.5
1
13.0
1 11.1
1 24.9 1
8.4
1
6.8
1 4.7 1
5.5
1 5.6
1
3.8
1 3.2
1 5.4
1 13.1
1
13.3
Hydraulic Radius ft
0.8
1
0.8
1 1.2
1 1.2
1 1.2 1
0.8
1 0.9
1
1.0
1 1.2
1 0.8 1
0.4
1
0.5
1 0.3 1
0.3
1 0.3
1
0.5
1 0.3
1 0.4
1 1.2
1
1.3
Substrate
Description D50
very fine gravel
fine gravel
very coarse sand
coarse sand
coarse sand
silt/muck
silt/muck
medium sand
very coarse sand
coarse sand to fine gravel
D16 mm
0.53
0.32
0.55
0.39
N/A
0.49
0.36
0.51
N/A
0.34
0.32
N/A
N/A
0.23
0.35
---
---
D50 mm
3.1
0.81
4.4
1.6
N/A
1.9
0.72
0.95
N/A
0.67
0.77
N/A
N/A
0.39
1.5
---
D84 mm
7.9
5.9
11
8.9
N/A
9.7
1.3
6.2
N/A
1.1
4.7
N/A
N/A
0.93
6.4
---
Pattern
Min
Max
Min
Max
---
---
---
---
---
Min
Max
---
---
---
---
---
---
Min
Max
Channel Beltwidth ft
19
45
19
57
---
---
---
---
---
12
38
---
---
---
---
---
34
70
Radius of Curvature ft
9
22
10
28
---
---
---
---
---
4
25
---
---
---
---
---
---
23
42
Radius of Curvature Ratio
0.7
1.8
0.9
2.6
---
---
---
---
---
0.7
4.1
---
---
---
---
---
---
1.9
3.4
Meander Wavelength ft
58
147
49
170
---
---
---
---
---
33
85
---
---
---
---
---
---
90
151
Meander Width Ratiol
1.6
1
3.7
1 1.6
1 5.3 1
---
I ---
I
---
---
--- 1
1.5
1
6.2
1
---
---
2.8
5.7
Profile
Min
Max
Min
Max
---
---
---
---
---
---
---
---
---
---
---
---
---
Min
Max
Shallow Length (ft)
2
22
5
23
---
---
---
---
---
---
---
---
---
---
---
13
48
Run Length ft
5
16
10
18
---
---
---
---
---
---
---
---
---
---
---
---
---
12
45
Pool Length ft
3.0
9.7
11.6
45.6
---
---
---
---
---
---
---
---
---
---
---
---
---
13
29
Pool -to-Pool Spacing ft
5.2
46.8
37.2
55.7
---
---
---
---
---
---
---
---
---
---
---
---
---
48
159
Additional Reach Parameters
Valley Length ft
901
842
1297
740
1198
722
647
775
607
---
Channel Length ft
1074
995
1388
808
1364
795
666
778
611
---
Sinuosity
1.19
1.18
1.07
1.09
1.14
1.10
1.03
1.00
1.01
1.2
Water Surface Slope ft/ft
0.008
0.29
---
---
---
---
---
---
---
---
Channel Slope ft/ft
0.008
0.003
0.002
0.001
0.0030
0.0080
0.02
0.0090
0.008-0.02
0.003
Ros en Classification
E4/5
E4/5
E5
E5
E5
G6c
E6
F5/G5c
G5c
E4/5
1 Bankfull stage was estimated using NC Regional Curve equations and existing conditions data
2 NC Regional Curve equations source: Doll et al. (2003;
3 NC Regional Curve equations source: Sweet and Geratz (2003

Upstream Downstream
Reach TH3 - XS1 (Run)
101.5
101
100.5
100
C
0
Y
> 99.5
d
W 99
98.5
98
0 5 10 15 20 25 30 35 40.
Distance (ft)
—*--Ground Approx. Bankfull Floodprone Area

102
101
100
c
99
0
Y
> 98
d
W 97
96
95
0
Upstream
Reach TH3 - XS2 (Run)
Downstream
5 10 15 20 25 30 35 40 45 50 55 60 65 70
Distance (ft)
--*—Ground Approx. Banl full Floodprone Area

Upstream Downstream
Reach HB4 - XS3 (Run)
101
100.5
100
99.5
C
0
M 99
>
_0
W 98.5
98
97.5
0 10 20 30 40 50 60 70 80
Distance (ft)
—*—Ground Approx. BankFull Floodprone Area

Upstream Downstream
Reach HB3 - XS4 (Shallow)
101
100.5
100
99.5 -
y
W
wO 99
M
a>i 98.5
W
98
97.5
97
0 5 10 15 20 25 30 35 40
Distance (ft)
--*—Ground Approx. Bankfull Floodprone Area

Upstream Downstream
Reach HB3 - XS5 (Pool)
102
101
100
y
99
O
m
> 98 - -
w
97 it
96
0 5 10 15 20 25 30 35 40.
Distance (ft)
—*--Ground Approx. Bankfull Floodprone Area

Upstream Downstream
Reach EA - XS6 (Shallow)
97.5
97
96.5
96
c
95.5
m
w 95
94.5
94
0 5 10 15 205
Distance (ft)
♦Ground Approx. BankFull Floodprone Area

k
40
,4
. fJ`
Upstream Downstream
Reach EA - XS7 (Run)
101
100.5
100
99.5
C
0
m 99
uJ 98.5
98
97.5
0 5 10 15 20 25 30
Distance (ft)
—*—Ground Approx. BankFull Floodprone Area

Upstream
Downstream
Reach HB3 - XS8 (Shallow)
103
102
101
100
0 99
Y
d 98
W
97
96
95
0 5 10 15 20 25 30 35 40
Distance (ft)
—*--Ground Approx. BankFull Floodprone Area

103
102
101
100
0 99
Y
> 98
W
97
96
95
� f
r"
4. t�
Upstream
Reach HB3 - XS9 (Pool)
Downstream
0 5 10 15 20 25 30 35
Distance (ft)
Ground Approx. Ban1dull Floodprone Area
40 45

102
101
ZFF 100
C
O
w
99
d
W
98
97
0
Upstream
Reach TH3 - XS10 (Run)
Downstream
5 10 15 20 25 30 35
Distance (ft)
—Ground Approx. Bankfull Floodprone Area
40 45

S
! V
tx Yt�
103
102
101
p 100
Y
W 99
98
97
0
Upstream
Reach HB1 - XS11 (Shallow)
Downstream
5 10 15 20 25
Distance (ft)
Reach B1 Approx. Bankfull Floodprone Area
30

NO5
`� '�6 7• �, " NX
r:
V
p I�,
Ac.
•y III � ;� fi � ri � ��<.
A
F�
Upstream
Downstream
Reach HB1 - XS12 (Pool)
103
102
101
100
c
0
99
m
U'
98
97
96
0 5 10 15 20 25 30 35 40
Distance (ft)
—*—Ground Approx. Banl full Floodprone Area

Upstream Downstream
Reach HF2 - XS13 (Run)
100
99
98
c
97
0
y
> 96
d
W
95
94
0 5 10 15 20 25 30 35 40
Distance (ft)
--*—Ground Approx. Bankfull Floodprone Area

Upstream Downstream
Reach HF1 - XS14 (Run)
100.8
100.6
100.4
100.2
100
04L 1-100
C 99.8
0
99.6
99.4
W
77
99.2
99
98.8
0 5 10 15 20 25 30 35 40
Distance (ft)
--e--Ground Approx. BankFull Floodprone Area

Upstream Downstream
Reach HF1 - XS15 (Run)
101
100.8
100.6
100.4
F100.2
c
w
100
m
ani 99.8
w
99.6
99.4
99.2
0 5 10 15 20 25 30 35 40
Distance (ft)
��Ground Approx. Bankfull Floodprone Area

Upstream
Downstream
Reach HB2 - XS16 (Pool) Reference
125
124
123
122
c
0
> 121
W
120
119
118
0 5 10 15 20 25 30 35
Distance (ft)
+Ground Approx. Ban1dull Floodprone Area

Upstream
Downstream
Reach HB2 - XS17 (Shallow) Reference
124
123.5
123
122.5
122
c
° 121.5
121
Lu
120.5
120
119.5
119
0 5 10 15 20 25 30
Distance (ft)
��Ground Approx. Bankfull Floodprone Area

Upstream Downstream
Reach HB2 - XS18 (Shallow) Reference
124
123.5
123
122.5
122
0
121.5
Lu 121
120.5
120
119.5
0 5 10 15 20 25 80 35
Distance (ft)
--*—Ground Approx. Bankfull Floodprone Area

Hannah Bridge Reach HB1/HB3
Hydraulic Design Data
Stable Channel Design Results - Copeland Method
d84(mm) = 9.0, D50(mm) = 2.0, D16(mm) = .50
Temperature (F) 55
Specific Gravity of Sediments 2.65
Unit Weight of Water (Ib/cu ft) 62.385
Viscosity (sq ft/s) 1.32E-05
Discharge (cfs) 30
Upstream Channel
Sediment Concentration (ppm)
153.64
Base Width (ft)
7
Channel Slope (ft/ft)
0.0032
Left
Right
Side Slope
1.6
1.6
Roughness Eq
Manning
Manning
Roughness Value
0.05
0.05
Stable Channel
Left
Right
Side Slope
1.6
1.6
Roughness Eq
Manning
Manning
Roughness Value
0.05
0.05
Computed Stable Channels
Bottom
Energy
Comp
Hyd
Froude
Shear
Width Depth
Slope
n -Value
Radius
Velocity
Number
Stress
Regime
1 2.4
0.005606
0.0471
1.15
2.58
0.29
0.84
Upper
2 2.2
0.004876
0.0469
1.18
2.46
0.29
0.67
Lower
3 2
0.004115
0.0458
1.2
2.36
0.29
0.52
Lower
4 1.9
0.003714
0.0444
1.19
2.3
0.3
0.43
Lower
5 1.7
0.003456
0.0431
1.16
2.26
0.3
0.37
Lower
7 1.5
0.003184
0.0401
1.09
2.2
0.32
0.29
Lower
8 1.4
0.003095
0.0395
1.06
2.18
0.33
0.26
Lower
9 1.3
0.003058
0.0387
1.02
2.16
0.34
0.24
Lower
10 1.2
0.003055
0.038
0.98
2.14
0.35
0.22
Lower
11 1.1
0.003045
0.0373
0.94
2.13
0.36
0.21
Lower
12 1
0.003058
0.0366
0.9
2.11
0.36
0.2
Lower
13 1
0.003108
0.0358
0.86
2.09
0.37
0.19
Lower
14 0.9
0.00313
0.0355
0.83
2.07
0.38
0.18
Lower
15 0.9
0.003151
0.0353
0.8
2.06
0.38
0.17
Lower
16 0.8
0.003189
0.0349
0.77
2.04
0.39
0.17
Lower
18 0.8
0.003294
0.0341
0.72
2.01
0.4
0.16
Lower
19 0.7
0.003317
0.0339
0.69
1.99
0.41
0.15
Lower
20 0.7
0.003374
0.0335
0.67
1.98
0.41
0.15
Lower
21 0.7
0.003429
0.0331
0.65
1.96
0.42
0.15
Lower
22 0.7
0.003469
0.0329
0.63
1.95
0.42
0.14
Lower
*******Solution for Minimum
Stream Power*******
10.9 1.1
0.003076
0.0369
0.93
2.12
0.35
0.21
Lower