SW3240704_Stormwater Report_20241029

I
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
MANAGEMENT REPORT
FOR:
HIDDEN ESTATES
WEDDINGTON, NC
PREPARED FOR:
ENCOMPASS BUILDING GROUP, LLC
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'3 • - THOMAS
C941EA5D7897403... & HUTTON
SEAL E - ENGINEERING i -
la 050698 = _ CO.
10/28/2024 c', No. F-0871 =o
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',,,,jj�••ENGINEER•�� �`�` -.°'-CqT£OF AU��c�.�`�,•
J -#29589.0000
OCTOBER 14, 2024
Prepared by:
HT THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER MANAGEMENT REPORT
Project: Hidden Estates
T&H Job Number: J-29589.0000
Location: Beulah Church Road
Weddington, NC 28173
Date Prepared: October 14, 2024
Owner: Encompass Building Group, LLC
Owner Address: 1016 Waxhaw/Indian Trail Rd.
Indian Trail, NC 28104
Engineer: Thomas & Hutton
Engineer Address: 1020 Euclid Avenue
Charlotte, NC 28203
Phone: [phone]
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
TABLE OF CONTENTS
Section 1 Channel Analysis
Section 2 Rip Rap Outlet Protection
Section 3 HEC-22 Stormwater Analysis
Section 4 Time of Concentration Calculations
Appendix A NOAA Rainfall Data
H THOMAS & HUTTON
Page 2

I
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
CALCULATIONS
HIDDEN ESTATES
SECTION 1
CHANNEL ANALYSIS
29589.0000
kr
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
29589.0000- Hidden Estates
Temporary Diversion Swale Calculations
10/11/2024
TDS-01
C i A ■ Q ---
- (in/hr) (ac) ■ (cfs) ---
Tc= 10.3 min 0.60 5.98 0.91 3.27 ---
10-yr storm ---■----
Avg. Slope from Surface: 4.57%

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday, Oct 11 2024
Swale 1 - Erosion Control Blanket- S75BN
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.48
Total Depth (ft) = 1.00 Q (cfs) = 3.270
Area (sqft) = 0.92
Invert Elev (ft) = 680.00 Velocity (ft/s) = 3.55
Slope (%) = 4.57 Wetted Perim (ft) = 3.97
N-Value = 0.032 Crit Depth, Yc (ft) = 0.53
Top Width (ft) = 3.84
Calculations EGL (ft) = 0.68
Compute by: Known Q
Known Q (cfs) = 3.27
Elev (ft) Section Depth (ft)
682.00 2.00
681.50 1.50
•
681.00 1.00
680.50 0.50
•
680.00 0.00
•
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday, Oct 11 2024
Swale 1 - Vegetated
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.46
Total Depth (ft) = 1.00 Q (cfs) = 3.270
Area (sqft) = 0.85
Invert Elev (ft) = 680.00 Velocity (ft/s) = 3.86
Slope (%) = 4.57 Wetted Perim (ft) = 3.80
N-Value = 0.030 Crit Depth, Yc (ft) = 0.53
Top Width (ft) = 3.68
Calculations EGL (ft) = 0.69
Compute by: Known Q
Known Q (cfs) = 3.27
Elev (ft) Section Depth (ft)
682.00 2.00
681.50 1.50
•
681.00 1.00
680.50 0 0.50
•
680.00 0.00
•
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
I V I-/I I/LY,V.LJ IVI
NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
>>>Swale 1
Name Swale 1
Discharge 3.3
Channel Slope 0.0457
Channel Bottom Width 0
Left Side Slope 5
Right Side Slope 3
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Very Good 80-95%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.6 lbs/ft2 1.34 lbs/ft2 1.19 STABLE D
Underlying Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.74 Ibs/ft2 0.65 Ibs/ft2 2.69 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 3.3 cfs 2.59 ft/s 0.57 ft 0.052 4 lbs/ft2 1.61 lbs/ft2 2.48 STABLE --
Vegetation
Underlying Straight 3.3 cfs 2.59 ft/s 0.57 ft 0.052 4 Ibs/ft2 0.78 Ibs/ft2 5.12 STABLE --
Substrate
S75BN
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S75BN Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.6 lbs/ft2 1.34 lbs/ft2 1.19 STABLE D
Unvegetated
Underlying Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.74 Ibs/ft2 0.65 Ibs/ft2 2.69 STABLE D
Substrate
DS75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
DS75 Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.6 lbs/ft2 1.34 lbs/ft2 1.19 STABLE D
Unvegetated
Underlying Straight 3.3 cfs 3.73 ft/s 0.47 ft 0.032 1.74 Ibs/ft2 0.65 Ibs/ft2 2.69 STABLE D
Substrate
https://ecmds.com/project/162496/channel-analysis/276030/show 1/2

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
ANALYSIS COMPUTATIONS
>>>>View Computation
Inputs
Channel Discharge(Q): 3.3 cfs
Peak Flow Period (H): hours
Channel Slope (S0): 0.0457 ft/ft
Bottom Width (B): 0 ft
Left Side Slope (ZL): 5 (H : V)
Right Side Slope(ZR): 3 (H : V)
Existing Channel Bend: No
Bend Coefficient(Kb): 1
Channel Bend Radius:
Retardance Class of Vegetation:C 6-12 in
Vegetation Type: Mix (Sod and Bunch)
Vegetation Density: Very Good 80-95%
Soil Type: Clay Loam (CL)
Channel Lining Options
DS75 Protection Type Temporary
S75BN Protection Type Temporary
S75 Protection Type Temporary
Basic Relationships
A = Cross sectional area, ft2(m2)_(B*D)+(ZL/2 * D2)+(ZR/2 * D2)
Where:
B = Base width of channel,ft(m)
D = Flow depth,ft(m)
ZL= Left side bank slope (H : 1 V)
ZR= Right side bank slope(H : 1 V)
P = Wetted perimeter,ft(m) = B + ZL* D + ZR* D
R=Hydraulic radius,ft(m)=A/P
V = Flow velocity,ft/s(m/s) = Q/A
Where:
Q = Channel discharge, cfs(cms)
Taua Average bed shear stress, psf(Pa) = 62.4* R* SO
Where:
SO = Gradient of channel,ft/ft(m/m)
Tauo= Maximum bed shear stress, psf(Pa) = 62.4 * D * So
Unvegetated Conditions Computations:
n = Manning's n = a *Tauab
and (iteratively solved).
n = 1.486/Q *A* R(2/3)Soo'S
Where:
n = Manning's n
https://ecmds.com/project/162496/channel-analysis/276030/calculations 1/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
a = Product specific coefficient from performance testing
b = Product specific coefficient from performance testing
SFR= Product factor of safety =Taur/Tauo
Where:
TauT= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =TauT/alpha * (Taus+ alpha/4.3)
Where:
alpha = unit conversion constant, 0.14 English, 6.5 Metric
Taus = Permissible shear stress of soil
SFL= Factor of safety of installed liner=Taup/Taua
Vegetated Computations:
n = Manning's n = alpha * Cn*Taua-0.4
and (iteratively solved).
n = 1.486/Q*A* R(2/3)So05
Where:
alpha = Unit conversion constant, 0.213 English, 1.0 Metric
Cn = Vegetation retardance coefficient
SFp= Product factor of safety =Taurv/Tauo
Where:
Taurv= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =Taus/(1 -CFTRM) * (n/ ns)2
Where:
CFTRM= Coefficient of TRM performance derived from testing Taus= Permissible shear stress of soil
ns= Manning's of soil bed if left unprotected
SFL= Factor of safety of installed liner=Taup/Taua
S75
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
575 Unvegetated 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 1.34 lbs/ft2 1.19(SFP)
Underlying 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 0.65 Ibs/ft2 2.69(SFL)
Substrate
Unreinforced Vegetation
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
Unreinforced 0.052 0.57 ft 1.28 ft2 4.67 ft 0.27 ft 2.59 ft/s 0.88 1.61 lbs/ft2 2.48(SFL)
Vegetation
Underlying 0.052 0.57 ft 1.28 ft2 4.67 ft 0.27 ft 2.59 ft/s 0.88 0.78 lbs/ft2 5.12(SFL)
Substrate
S75BN
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
S75BN 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 1.34 lbs/ft2 1.19(SFP)
Unvegetated
Underlying 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 0.65 lbs/ft2 2.69(SFL)
Substrate
https://ecmds.com/project/162496/channel-analysis/276030/calculations 2/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
DS75
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
DS75 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 1.34 lbs/ft2 1.19(SFP)
Unvegetated
Underlying 0.032 0.47 ft 0.88 ft2 3.88 ft 0.23 ft 3.73 ft/s 1.37 0.65 lbs/ft2 2.69(SFL)
Substrate
https://ecmds.com/project/162496/channel-analysis/276030/calculations 3/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
29589.0000- Hidden Estates
Temporary Diversion Swale Calculations
10/11/2024
TDS-02
C i A ■ Q ---
- (in/hr) (ac) ■ (cfs) ---
Tc= 10.3 min 0.60 5.98 0.92 3.30 ---
10-yr storm ---■----
Avg. Slope from Surface: 19.82%

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday, Oct 11 2024
Swale 2 - Vegetated
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.35
Total Depth (ft) = 1.00 Q (cfs) = 3.300
Area (sqft) = 0.49
Invert Elev (ft) = 680.00 Velocity (ft/s) = 6.73
Slope (%) = 19.82 Wetted Perim (ft) = 2.89
N-Value = 0.030 Crit Depth, Yc (ft) = 0.54
Top Width (ft) = 2.80
Calculations EGL (ft) = 1.06
Compute by: Known Q
Known Q (cfs) = 3.30
Elev (ft) Section Depth (ft)
682.00 2.00
681.50 1.50
•
681.00 1.00
680.50 0.50
•
680.00 0.00
•
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday, Oct 11 2024
Swale 2 - Reinforced Vegetation-S200
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.37
Total Depth (ft) = 1.00 Q (cfs) = 3.300
Area (sqft) = 0.55
Invert Elev (ft) = 680.00 Velocity (ft/s) = 6.03
Slope (%) = 19.82 Wetted Perim (ft) = 3.06
N-Value = 0.034 Crit Depth, Yc (ft) = 0.54
Top Width (ft) = 2.96
Calculations EGL (ft) = 0.93
Compute by: Known Q
Known Q (cfs) = 3.30
Elev (ft) Section Depth (ft)
682.00 2.00
681.50 1.50
•
681.00 1.00
680.50 0.50
0
•
680.00 0.00
•
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
kiNORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
>>>Swale 2
Name Swale 2
Discharge 3.3
Channel Slope 0.1982
Channel Bottom Width 0
Left Side Slope 5
Right Side Slope 3
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Very Good 80-95%
Soil Type Clay Loam(CL)
S200
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S200 Straight 3.3 cfs 7.51 ft/s 0.33 ft 0.026 2.3 lbs/ft2 4.07 lbs/ft2 0.56 UNSTABLE E
Unvegetated
Underlying Straight 3.3 cfs 7.51 ft/s 0.33 ft 0.026 2.51 Ibs/ft2 1.97 lbs/ft2 1.27 STABLE E
Substrate
S200 Reinforced Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 10 lbs/ft2 4.54 lbs/ft2 2.2 STABLE E
Vegetation
Underlying Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 3.91 lbs/ft2 2.2 lbs/ft2 1.78 STABLE E
Substrate
SC250
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Underlying Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 3.91 lbs/ft2 2.2 lbs/ft2 1.78 STABLE E
Substrate
SC250 Straight 3.3 cfs 6.88 ft/s 0.35 ft 0.029 3 lbs/ft2 4.28 lbs/ft2 0.7 UNSTABLE E
Unvegetated
Underlying Straight 3.3 cfs 6.88 ft/s 0.35 ft 0.029 3.27 lbs/ft2 2.07 lbs/ft2 1.58 STABLE E
Substrate
SC250 Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 10 lbs/ft2 4.54 lbs/ft2 2.2 STABLE E
Reinforced
Vegetation
C350
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
-
C350 Straight 3.3 cfs 6.64 ft/s 0.35 ft 0.031 3.2 lbs/ft2 4.36 lbs/ft2 0.73 UNSTABLE E
Unvegetated
Underlying Straight 3.3 cfs 6.64 ft/s 0.35 ft 0.031 3.49 lbs/ft2 2.11 lbs/ft2 1.65 STABLE E
Substrate
C350 Reinforced Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 12 lbs/ft2 4.54 lbs/ft2 2.64 STABLE E
Vegetation
Underlying Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 6 lbs/ft2 2.2 lbs/ft2 2.73 STABLE E
Substrate
Unreinforced Vegetation
https://ecmds.com/project/162496/channel-analysis/276029/show 1/2

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9.�,I I/LY,V.Ll)I-IVI ECMDS 7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 4 Ibs/ft2 4.54 Ibs/ft2 0.88 UNSTABLE --
Vegetation
Underlying Straight 3.3 cfs 6.12 ft/s 0.37 ft 0.034 2.61 lbs/ft2 2.2 Ibs/ft2 1.19 STABLE --
Substrate
DS75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
DS75 Straight 3.3 cfs 7.24 ft/s 0.34 ft 0.027 1.6 lbs/ft2 4.18 lbs/ft2 0.38 UNSTABLE D
Unvegetated
Underlying Straight 3.3 cfs 7.24 ft/s 0.34 ft 0.027 1.74 lbs/ft2 2.02 Ibs/ft2 0.86 UNSTABLE D
Substrate
https://ecmds.com/project/162496/channel-analysis/276029/show 2/2

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
kiNORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
ANALYSIS COMPUTATIONS
>>>>View Computation
Inputs
Channel Discharge(Q): 3.3 cfs
Peak Flow Period (H): hours
Channel Slope (S0): 0.1982 ft/ft
Bottom Width (B): 0 ft
Left Side Slope (ZL): 5 (H : V)
Right Side Slope(ZR): 3 (H : V)
Existing Channel Bend: No
Bend Coefficient(Kb): 1
Channel Bend Radius:
Retardance Class of Vegetation:C 6-12 in
Vegetation Type: Mix (Sod and Bunch)
Vegetation Density: Very Good 80-95%
Soil Type: Clay Loam (CL)
Channel Lining Options
DS75 Protection Type Temporary
C350 Protection Type Permanent
SC250 Protection Type Permanent
S200 Protection Type Permanent
Basic Relationships
A = Cross sectional area, ft2(m2)_(B*D)+(ZL/2 * D2)+(ZR/2 * D2)
Where:
B = Base width of channel, ft(m)
D = Flow depth,ft(m)
ZL= Left side bank slope(H : 1 V)
ZR= Right side bank slope(H : 1 V)
P = Wetted perimeter,ft(m) = B + ZL* D + ZR* D
R=Hydraulic radius,ft(m)=A/P
V = Flow velocity,ft/s(m/s) = Q/A
Where:
Q = Channel discharge, cfs(cms)
Taua Average bed shear stress, psf(Pa) = 62.4* R* SO
Where:
SO = Gradient of channel,ft/ft(m/m)
Tauo= Maximum bed shear stress, psf(Pa) = 62.4 * D * So
Unvegetated Conditions Computations:
n = Manning's n = a *Tauab
and (iteratively solved).
n = 1.486/Q *A* R(2/3)So05
Where:
https://ecmds.com/project/162496/channel-analysis/276029/calculations 1/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
n = Manning's n
a = Product specific coefficient from performance testing
b = Product specific coefficient from performance testing
SFP= Product factor of safety =Taur/Tauo
Where:
TauT= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =TauT/alpha * (Taus+ alpha/4.3)
Where:
alpha = unit conversion constant, 0.14 English, 6.5 Metric
Taus = Permissible shear stress of soil
SFL= Factor of safety of installed liner=Taup/Taua
Vegetated Computations:
n = Manning's n = alpha * Cn*Taua-0.4
and (iteratively solved).
n = 1.486/Q*A* R(2/3)Soo'5
Where:
alpha = Unit conversion constant, 0.213 English, 1.0 Metric
Cn = Vegetation retardance coefficient
SFR= Product factor of safety =Taurv/Tauo
Where:
TauTv= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =Taus/(1 -CFTRM) * (n/ ns)2
Where:
CFTRM= Coefficient of TRM performance derived from testing Taus= Permissible shear stress of soil
ns= Manning's of soil bed if left unprotected
SFL= Factor of safety of installed liner=Taup/Taua
S200
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
S200 0.026 0.33 ft 0.43 ft2 2.72 ft 0.16 ft 7.51 ft/s 3.31 4.07 lbs/ft2 0.56(SFP)
Unvegetated
Underlying 0.026 0.33 ft 0.43 ft2 2.72 ft 0.16 ft 7.51 ft/s 3.31 1.97 lbs/ft2 1.27(SFL)
Substrate
S200 Reinforced 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 4.54 lbs/ft2 2.2(SFP)
Vegetation
Underlying 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 2.2 lbs/ft2 1.78(SFL)
Substrate
SC250
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
Underlying 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 2.2 lbs/ft2 1.78(SFP)
Substrate
SC250 0.029 0.35 ft 0.48 ft2 2.86 ft 0.17 ft 6.88 ft/s 2.94 4.28 lbs/ft2 0.7(SFL)
Unvegetated
Underlying 0.029 0.35 ft 0.48 ft2 2.86 ft 0.17 ft 6.88 ft/s 2.94 2.07 lbs/ft2 1.58(SFP)
Substrate
SC250 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 4.54 lbs/ft2 2.2(SFL)
Reinforced
Vegetation
https://ecmds.com/project/162496/channel-analysis/276029/calculations 2/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
C350
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
C350 0.031 0.35 ft 0.5 ft2 2.91 ft 0.17 ft 6.64 ft/s 2.84 4.36 lbs/ft2 0.73(SFP)
Unvegetated
Underlying 0.031 0.35 ft 0.5 ft2 2.91 ft 0.17 ft 6.64 ft/s 2.84 2.11 lbs/ft2 1.65 (SFL)
Substrate
C350 Reinforced 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 4.54 lbs/ft2 2.64(SFP)
Vegetation
Underlying 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 2.2 lbs/ft2 2.73 (SFL)
Substrate
Unreinforced Vegetation
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
Unreinforced 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 4.54 lbs/ft2 0.88(SFL)
Vegetation
Underlying 0.034 0.37 ft 0.54 ft2 3.03 ft 0.18 ft 6.12 ft/s 2.54 2.2 lbs/ft2 1.19(SFL)
Substrate
DS75
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
DS75 0.027 0.34 ft 0.46 ft2 2.79 ft 0.16 ft 7.24 ft/s 3.19 4.18 lbs/ft2 0.38(SFP)
Unvegetated
Underlying 0.027 0.34 ft 0.46 ft2 2.79 ft 0.16 ft 7.24 ft/s 3.19 2.02 lbs/ft2 0.86(SFL)
Substrate
https://ecmds.com/project/162496/channel-analysis/276029/calculations 3/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
29589.0000- Hidden Estates
Temporary Diversion Swale Calculations
10/11/2024
TDS-03
C i A Q TOP 689.97
(in/hr) (ac) (cfs) BOT 670.36
Tc= 11 min 0.60 5.85 0.35 1.23 LENGTH 405.1
10-yr storm
SLOPE 4.84%

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday, Oct 11 2024
Swale 3 - Erosion Control Blanket - S75BN
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.33
Total Depth (ft) = 1.00 Q (cfs) = 1.230
Area (sqft) = 0.44
Invert Elev (ft) = 680.00 Velocity (ft/s) = 2.82
Slope (%) = 4.84 Wetted Perim (ft) = 2.73
N-Value = 0.032 Crit Depth, Yc (ft) = 0.36
Top Width (ft) = 2.64
Calculations EGL (ft) = 0.45
Compute by: Known Q
Known Q (cfs) = 1.23
Elev (ft) Section Depth (ft)
682.00 2.00
681.50 1.50
•
681.00 1.00
680.50 0.50
•
680.00 0.00
•
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Friday,Oct 11 2024
Swale 3 - Vegetated
Triangular Highlighted
Side Slopes (z:1) = 5.00, 3.00 Depth (ft) = 0.32
Total Depth (ft) = 1.00 Q (cfs) = 1.230
Area (sqft) = 0.41
Invert Elev (ft) = 680.00 Velocity (ft/s) = 3.00
Slope (%) = 4.84 Wetted Perim (ft) = 2.64
N-Value = 0.030 Crit Depth, Yc (ft) = 0.36
Top Width (ft) = 2.56
Calculations EGL (ft) = 0.46
Compute by: Known Q
Known Q (cfs) = 1.23
Elev (ft) Section Depth (ft)
682.00 - 2.00
681.50 - 1.50
681.00 1.00
680.50 0.50
680.00 0.00
679.50 -0.50
0 1 2 3 4 5 6 7 8 9 10
Reach (ft)

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
I V I-/I I/LY,V.JJ IVI
NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
>>>Swale 3
Name Swale 3
Discharge 1.23
Channel Slope 0.0484
Channel Bottom Width 0
Left Side Slope 5
Right Side Slope 3
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Very Good 80-95%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.6 lbs/ft2 0.99 lbs/ft2 1.62 STABLE D
Underlying Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.74 Ibs/ft2 0.48 Ibs/ft2 3.66 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 1.23 cfs 1.9 ft/s 0.4 ft 0.058 4 lbs/ft2 1.22 Ibs/ft2 3.29 STABLE --
Vegetation
Underlying Straight 1.23 cfs 1.9 ft/s 0.4 ft 0.058 4 Ibs/ft2 0.59 lbs/ft2 6.79 STABLE --
Substrate
S75BN
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S75BN Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.6 lbs/ft2 0.99 lbs/ft2 1.62 STABLE D
Unvegetated
Underlying Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.74 lbs/ft2 0.48 lbs/ft2 3.66 STABLE D
Substrate
DS75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
DS75 Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.6 lbs/ft2 0.99 lbs/ft2 1.62 STABLE D
Unvegetated
Underlying Straight 1.23 cfs 2.89 ft/s 0.33 ft 0.033 1.74 lbs/ft2 0.48 lbs/ft2 3.66 STABLE D
Substrate
https://ecmds.com/project/162496/channel-analysis/276031/show 1/2

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
I V/I I/LY,V.JY r IVI
NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
ANALYSIS COMPUTATIONS
>>>>View Computation
Inputs
Channel Discharge(Q): 1.23 cfs
Peak Flow Period (H): hours
Channel Slope (S0): 0.0484 ft/ft
Bottom Width (B): 0 ft
Left Side Slope (ZL): 5 (H : V)
Right Side Slope(ZR): 3 (H : V)
Existing Channel Bend: No
Bend Coefficient(Kb): 1
Channel Bend Radius:
Retardance Class of Vegetation:C 6-12 in
Vegetation Type: Mix (Sod and Bunch)
Vegetation Density: Very Good 80-95%
Soil Type: Clay Loam (CL)
Channel Lining Options
DS75 Protection Type Temporary
S75BN Protection Type Temporary
S75 Protection Type Temporary
Basic Relationships
A = Cross sectional area, ft2(m2)_(B*D)+(ZL/2 * D2)+(ZR/2 * D2)
Where:
B = Base width of channel,ft(m)
D = Flow depth,ft(m)
ZL= Left side bank slope (H : 1 V)
ZR= Right side bank slope(H : 1 V)
P = Wetted perimeter,ft(m) = B + ZL* D + ZR* D
R=Hydraulic radius,ft(m)=A/P
V = Flow velocity,ft/s(m/s) = Q/A
Where:
Q = Channel discharge, cfs(cms)
Taua Average bed shear stress, psf(Pa) = 62.4* R* SO
Where:
SO = Gradient of channel,ft/ft(m/m)
Tauo= Maximum bed shear stress, psf(Pa) = 62.4 * D * So
Unvegetated Conditions Computations:
n = Manning's n = a *Tauab
and (iteratively solved).
n = 1.486/Q *A* R(2/3)So°5
Where:
n = Manning's n
https://ecmds.com/project/162496/channel-analysis/276031/calculations 1/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
I V/I I/LY, IVI V.JY r
a = Product specific coefficient from performance testing
b = Product specific coefficient from performance testing
SFR= Product factor of safety =Taur/Tauo
Where:
TauT= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =TauT/alpha * (Taus+ alpha/4.3)
Where:
alpha = unit conversion constant, 0.14 English, 6.5 Metric
Taus = Permissible shear stress of soil
SFL= Factor of safety of installed liner=Taup/Taua
Vegetated Computations:
n = Manning's n = alpha * Cn*Taua-0.4
and (iteratively solved).
n = 1.486/Q*A* R(2/3)So05
Where:
alpha = Unit conversion constant, 0.213 English, 1.0 Metric
Cn = Vegetation retardance coefficient
SFR= Product factor of safety =Taurv/Tauo
Where:
Taurv= Permissible shear stress from testing, psf(Pa)
Taup= In place permissible shear, psf(Pa) =Taus/(1 -CFTRM) * (n/ ns)2
Where:
CFTRM= Coefficient of TRM performance derived from testing Taus= Permissible shear stress of soil
ns= Manning's of soil bed if left unprotected
SFL= Factor of safety of installed liner=Taup/Taua
S75
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
575 Unvegetated 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.99 lbs/ft2 1.62(SFP)
Underlying 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.48 Ibs/ft2 3.66(SFL)
Substrate
Unreinforced Vegetation
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
Unreinforced 0.058 0.4 ft 0.65 ft2 3.33 ft 0.19 ft 1.9 ft/s 0.77 1.22 lbs/ft2 3.29(SFL)
Vegetation
Underlying 0.058 0.4 ft 0.65 ft2 3.33 ft 0.19 ft 1.9 ft/s 0.77 0.59 lbs/ft2 6.79(SFL)
Substrate
S75BN
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
S75BN 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.99 lbs/ft2 1.62(SFP)
Unvegetated
Underlying 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.48 lbs/ft2 3.66(SFL)
Substrate
https://ecmds.com/project/162496/channel-analysis/276031/calculations 2/3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 ECMDS 7.0
I V Y/I I/LY,V.V I-IVI
DS75
Predicted flow Cross sectional Wetted Hydraulic Flow velocity Froude Calculated Shear
Phase Mannings N SFP/SFL
depth(D) area(A) perimeter(P) radius(R) (V) number(FR) Stress
DS75 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.99 lbs/ft2 1.62(SFP)
Unvegetated
Underlying 0.033 0.33 ft 0.43 ft2 2.69 ft 0.16 ft 2.89 ft/s 1.27 0.48 lbs/ft2 3.66(SFL)
Substrate
https://ecmds.com/project/162496/channel-analysis/276031/calculations 3/3

I
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
CALCULATIONS
HIDDEN ESTATES
SECTION 2
RIP RAP OUTLET PROTECTION
29589.0000
kr
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Rip Rap Apron Design
Project Name: 29589.0000 -Hidden Estates FES 1
Drainage Specialist: SHD Date: October 11,2024
Checked By: NW Date: October 11,2024
Step 1. Determine the tailwater depth from the channel characteristics below the pipe outlet for the
design capacity of the pipe. If the tailwater depth is less than half the outlet pipe diameter, it
is classifies as minimum tailwater conditions. If the tailwater is greater than half the pipe
diameter, it is classified as maximum tailwater conditions. Pipes that outlet onto wide flat
areas with no defined channel are assumed to have a minimum tailwater condition unless
reliable flood stage elevations show otherwise.
Rational Method for Flow
Total Drainage Area(Acres): 1.4
Outlet pipe diameter,Do(in.) 18
Tailwater depth(Feet) 0.5
Tailwater Method To Be Used Min TW(Fig.8.06a)
Discharge(cfs) 6.8
Velocity(ft./s) 16.0
Step 2. Based on the tailwater conditions determined in Step 1, enter Figure 8.06a or Figure 8.06b
and determine the d50 rip rap size and minimum apron length(La). The d50 size is the median
stone size in a well-graded rip rap apron.
Step 3. Determine the apron width at the pipe outlet,the apron shape, and the apron width at the
outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Riprap d50, (ft.) 0.5
Minimum apron length, La(ft.) ** 10
Apron width at pipe outlet(ft.) 5
Apron shape W=Do+La
Apron width at outlet end(ft.) 12
**-Minimum Apron Length Is 10 Feet per CLDS 20.23
Step 4. Determine the maximum Stone Diameter. D.= 1.5 X d50
Determine the Apron Thickness,Ta= 1.5 X d,nax
Minimum TW Maximum TW
Max Stone Diameter, dmax(Inches): 9 71=
Apron Thickness (Inches): 14
**-Minimum Apron Thickness Is 10 Inches per CLDS 20.23
Step 5. Fit the rip rap apron to the site by making it level for the minimum length La. Extend the
apron farther downstream and along the channel banks until stability is assured. Keep apron
as straight as possible and align it with the flow of the receiving stream. Make any necessary
alignment bends near the pipe outlet so that the entrance into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure stability. It
may be necessary to increase the size of the rip rap where protection of the channel side
slopes is necessary. Where overfalls exist at pipe outlets or flows are excessive, a plunge pool
should be considered.

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
i .y ... ., .,.,w. ....�.�.. . �•...• M. •... •. .. .. ... .. ..,.. nd pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3(.7..._
Outlet - W = Do + La •a. •I
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pipe -
diameter (Do) --` . r,•,
,. La --(NI AO t -- Alf
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43
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V s ,k r . •' o
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3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Tw<0.5 diameter).
Rev.1V93 8.06.3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Rip Rap Apron Design
Project Name: 29589.0000 -Hidden Estates FES 2
Drainage Specialist: SHD Date: October 11,2024
Checked By: NW Date: October 11,2024
Step 1. Determine the tailwater depth from the channel characteristics below the pipe outlet for the
design capacity of the pipe. If the tailwater depth is less than half the outlet pipe diameter, it
is classifies as minimum tailwater conditions. If the tailwater is greater than half the pipe
diameter, it is classified as maximum tailwater conditions. Pipes that outlet onto wide flat
areas with no defined channel are assumed to have a minimum tailwater condition unless
reliable flood stage elevations show otherwise.
Rational Method for Flow
Total Drainage Area(Acres): 1.7
Outlet pipe diameter,Do(in.) 18
Tailwater depth(Feet) 0.5
Tailwater Method To Be Used Min TW(Fig.8.06a)
Discharge(cfs) 7.1
Velocity(ft./s) 4.8
Step 2. Based on the tailwater conditions determined in Step 1, enter Figure 8.06a or Figure 8.06b
and determine the d50 rip rap size and minimum apron length(La). The d50 size is the median
stone size in a well-graded rip rap apron.
Step 3. Determine the apron width at the pipe outlet,the apron shape, and the apron width at the
outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Riprap d50, (ft.) 0.5
Minimum apron length, La(ft.) ** 10
Apron width at pipe outlet(ft.) 5
Apron shape W=Do+La
Apron width at outlet end(ft.) 12
**-Minimum Apron Length Is 10 Feet per CLDS 20.23
Step 4. Determine the maximum Stone Diameter. D.= 1.5 X d50
Determine the Apron Thickness,Ta= 1.5 X d,nax
Minimum TW Maximum TW
Max Stone Diameter, dmax(Inches): 9 71=
Apron Thickness (Inches): 14
**-Minimum Apron Thickness Is 10 Inches per CLDS 20.23
Step 5. Fit the rip rap apron to the site by making it level for the minimum length La. Extend the
apron farther downstream and along the channel banks until stability is assured. Keep apron
as straight as possible and align it with the flow of the receiving stream. Make any necessary
alignment bends near the pipe outlet so that the entrance into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure stability. It
may be necessary to increase the size of the rip rap where protection of the channel side
slopes is necessary. Where overfalls exist at pipe outlets or flows are excessive, a plunge pool
should be considered.

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
i .y ... ., .,.,w. ....,.w.. . . ....• M. .... .. .. .. ... .. ..,.anu pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3(.c.•__
Outlet W = Do + La a. •'
-
j
pipe -
diameter (Lb) --` . r,
Da _et 30 t -- ' r,
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p�°� !I i . . Ii' � a
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43
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3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Ty,<0.5 diameter).
Rev.1V93 8.06.3

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Rip Rap Apron Design
Project Name: 29589.0000 - Hidden Estates Swale #2 Ou1
Drainage Specialist: SHD Date: October 11, 2024
Checked By: NW Date: October 11, 2024
Step 1. Determine the tailwater depth from the channel characteristics below the pipe outlet for the
design capacity of the pipe. If the tailwater depth is less than half the outlet pipe diameter, it
is classifies as minimum tailwater conditions. If the tailwater is greater than half the pipe
diameter, it is classified as maximum tailwater conditions. Pipes that outlet onto wide flat
areas with no defined channel are assumed to have a minimum tailwater condition unless
reliable flood stage elevations show otherwise.
Rational Method for Flow
Total Drainage Area(Acres): 0.9
Outlet pipe diameter,Do(in.) 18
Tailwater depth(Feet) 0.5
Tailwater Method To Be Used Min TW (Fig. 8.06a)
Discharge (cfs) 3.3
Velocity(ft./s) 6.0
Step 2. Based on the tailwater conditions determined in Step 1, enter Figure 8.06a or Figure 8.06b
and determine the d50 rip rap size and minimum apron length(La). The d50 size is the median
stone size in a well-graded rip rap apron.
Step 3. Determine the apron width at the pipe outlet,the apron shape, and the apron width at the
outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Riprap d50, (ft.) 0.5
Minimum apron length, La(ft.) ** 10
Apron width at pipe outlet(ft.) 5
Apron shape W=Do+La
Apron width at outlet end(ft.) 12 IM
**-Minimum Apron Length Is 10 Feet per CLDS 20.23
Step 4. Determine the maximum Stone Diameter. Dmax= 1.5 X d50
Determine the Apron Thickness,Ta= 1.5 X dmax
Minimum TW Maximum TW
Max Stone Diameter, dmax (Inches): 9 laMI- 1
Apron Thickness (Inches): 14
**-Minimum Apron Thickness Is 10 Inches per CLDS 20.23
Step 5. Fit the rip rap apron to the site by making it level for the minimum length La. Extend the
apron farther downstream and along the channel banks until stability is assured. Keep apron
as straight as possible and align it with the flow of the receiving stream. Make any necessary
alignment bends near the pipe outlet so that the entrance into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure stability. It
may be necessary to increase the size of the rip rap where protection of the channel side
slopes is necessary. Where overfalls exist at pipe outlets or flows are excessive, a plunge
pool should be considered.

Ih
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
i .W..6. .0.1,.0 • 1W.1 .,. 104116.11,..,....,...,.. 1..,... w .., and pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
Outlet f W • Do Ld 93 l
pipe
I •� N/
diameter (Do) % ;.;4
La -61 • Iri.j . /1'
j _ I •7" L ! , Ham._
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Discharge (ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Tw<0.5 diameter).
Rev.12 93 8.06.3

I
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
CALCULATIONS
HIDDEN ESTATES
SECTION 3
HEC-22 STORMWATER ANALYSIS
29589.0000
ITI
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
25-YR
CAPAC I TY

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
HEC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) (ft/s) U/S D/S
6 2 90 0.35 0.50 11 8.15 7.1 7.1 18 7.4 4.21 4.78 665.20 664.75 0.50%
1 16 15 i 1.38 0.50 5 9.871 6.8 6.8 18 37.0 20.96 15.99 667.00 665.20 12.41%
FTI THOMAS&HUTTON
Z:i29589i29589.00001Engineering\Calculations and RepartslStarm Water\HEC-22\HEC-22 Reporting.xlsm

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
HEC-22
Energy Grade Line Computations
Struct. Q EGLo HGLo Total Pipe EGLi HGLi Ea EGLa Surface Elev.
ID (cfs) (ft) (ft) Loss (ft) (ft) (ft) (ft) (ft)
(ft)
2 664.75 664.75 666.46
6 7.1 666.28 665.92 _ _ 0.45 666.73 666.37 1.8 667.02 670.31
1 6.8 667.11 666.88 671.41 667.44 4.4 671.41 668.71
Ti THOMAS& HUTTON
Z:129589129589.0000\Engineering\Calculations and Reports\Storm Water\HEC-22\HEC-22 Reporting.xlsm

I
Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
CALCULATIONS
HIDDEN ESTATES
SECTION 4
TIME OF CONCENTRATION CALCULATIONS
29589.0000
kr
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Time of Concentration Calculations (SCS Method)
Hidden Estates
Weddington, NC
Time of Concentration - SW 1
2-year, 24 hour rainfall (in.)= 3.53
Time of Concentration - SW 1
Flow Average Vel.(V) Mannings Travel Time
I,Path Length Type of Flow Slope
(ft) (ft/ft) (ft/s) n (minutes)
Segment AB 70.43 Sheet(unpaved) 0.105 0.15 0.4 8.0
Segment BC 520.22 Channel Flow 0.046 3.99 0.031 2.2
Total I 590.65 I I I I Tc=I 10.2
Flow Types
A Sheet Flow Tt= [0.007 (nL)°81/[(P2)°5* (S)1341
B Shallow Concentrated Flow
paved Tt= L/(60V) V=20.3282(S)112
unpaved Tt= L/(60V) V= 16.1345 (S)112
C Pipe Flow Tt= L/(60V) V= ((s)112(d)213)/8.9n
D Channel Flow Tt= L/(60V) V= (1.49 (r)"' (s)"`)/n

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Time of Concentration Calculations (SCS Method)
Hidden Estates
Weddington, NC
Time of Concentration - SW 2
2-year, 24 hour rainfall (in.)= 3.53
Time of Concentration - SW 2
Flow Average Vel.(V) Mannings Travel Time
I,Path Length Type of Flow Slope
(ft) (ft/ft) (ft/s) n (minutes)
Segment AB 49.38 Channel Flow 0.198 8.31 0.031 0.1
Total I 49.38 I I I I Tc=I 0.1
Flow Types
A Sheet Flow Tt= [0.007 (nL)0 8]/[(P2)°.5* (S)°.4]
B Shallow Concentrated Flow
paved Tt= L/(60V) V=20.3282(S)112
unpaved Tt= L/(60V) V= 16.1345 (S)112
C Pipe Flow Tt= L/(60V) V= ((s)1/2(d)213)/8.9n
D Channel Flow Tt= L/(60V) V= (1.49 (r)"' (s)"`)/n

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
Time of Concentration Calculations (SCS Method)
Hidden Estates
Weddington, NC
Time of Concentration - SW 3
2-year, 24 hour rainfall (in.)= 3.53
Time of Concentration - SW 3
Flow Average Vel.(V) Mannings Travel Time
Tc Path Length Type of Flow Slope
(ft) (ft/ft) (ft/s) n (minutes)
Segment AB 87.12 Sheet(unpaved) 0.105 0.15 0.4 9.4
Segment BC 405.13 Channel Flow 0.048 4.11 0.031 1.6
Total I 492.25 I I I I Tc=I 11.0
Flow Types
A Sheet Flow Tt= [0.007 (nL)°81/[(P2)°5* (S)1341
B Shallow Concentrated Flow
paved Tt= L/(60V) V=20.3282(S)112
unpaved Tt= L/(60V) V= 16.1345 (S)112
C Pipe Flow Tt= L/(60V) V= ((s)112(d)213)/8.9n
D Channel Flow Tt= L/(60V) V= (1.49 (r)"' (s)"`)/n

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9
EROSION CONTROL AND STORMWATER
CALCULATIONS
HIDDEN ESTATES
APPENDIX A
NOAA RAINFALL DATA
29589.0000
kr
THOMAS & HUTTON

Docusign Envelope ID:406FAA5D-4EE9-4B41-89F8-F8FCEE2BFED9 Precipitation Frequency Data Server
NOAA Atlas 14,Volume 2,Version 3
"rt°` Location name: Matthews,North Carolina,USA* '�� ''`*
''54 Latitude:35.0208°, Longitude:-80.7218° none
Elevation:669 ft**p
fi *source:ESRI Maps i,
e"T8°`' **source:USGS "`"'"`'�
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average recurrence interval(years)
Duration -
1 2 5 10 25 50 100 200 500 1000
5-min 5.00 5.90 6.86 7.55 8.35 8.89 9.40 9.84 10.3 10.7
(4.61-5.42) (5.44-6.43) (6.30-7.46) (6.92-8.20) (7.62-9.05) (8.09-9.64) (8.50-10.2) (8.86-10.7) _(9.23-11.2) (9.48-11.7)
10-min 4.00 4.72 5.49 6.04 6.65 7.08 7.46 7.80 8.18 8.43
(3.68-4.34) (4.35-5.14) (5.05-5.98) (5.54-6.55) (6.07-7.21) (6.44-7.67) (6.75-8.08) (7.02-8.45) (7.30-8.89) (7.46-9.17)
15-min 3.33 3.96 4.63 5.09 5.62 5.98 6.29 6.56 6.87 7.06
(3.07-3.61) (3.65-4.31) (4.25-5.04) (4.67-5.53) (5.13-6.09) (5.43-6.48) (5.69-6.81) (5.90-7.11) (6.12-7.46) (6.24-7.68)
30-min 2.28 2.73 3.29 3.69 4.16 4.50 4.82 5.11 5.46 5.71
(2.10-2.48) (2.52-2.98) (3.02-3.58) (3.38-4.00) (3.80-4.51) (4.09-4.88) (4.36-5.22) (4.59-5.54) (4.87-5.93) (5.06-6.22)
60-min 1.42 1.72 2.11 2.40 2.77 3.05 3.32 3.58 3.92 4.17
(1.31-1.54) (1.58-1.87) (1.94-2.30) (2.20-2.61) (2.53-3.00) (2.77-3.30) (3.00-3.59) (3.22-3.88) (3.50-4.26) (3.69-4.54)
2-hr 0.823 0.995 1.23 1.42 1.65 1.83 2.01 2.18 2.42 2.60
(0.754-0.900) (0.912-1.09) (1.13-1.35) (1.29-1.55) (1.50-1.80) (1.65-1.99) (1.80-2.19) (1.95-2.38) (2.14-2.64)_ (2.28-2.84)
3-hr 0.582 0.702 0.876 1.01 1.19 1.34 1.48 1.63 1.84 2.00
(0.532-0.640) (0.643-0.772) (0.800-0.962) (0.921-1.11) (1.08-1.30) (1.20-1.46)_ (1.33-1.62) (1.45-1.78) (1.61-2.00) (1.73-2.18)
6-hr 0.351 0.423 0.528 0.610 0.723 0.812 0.904 0.999 1.13 1.24
(0.321-0.385) (0.387-0.464) (0.483-0.579) (0.557-0.668) (0.655-0.788) (0.732-0.885) (0.809-0.984) (0.886-1.09) (0.989-1.23) (1.07-1.34)
12-hr 0.206 0.248 0.311 0.362 0.432 0.489 0.548 0.610 0.697 0.767
(0.189-0.225) (0.228-0.273) (0.285-0.342) (0.330-0.396) (0.392-0.472) (0.440-0.533) (0.488-0.596) (0.537-0.663) (0.604-0.757) (0.656-0.834)I
24-hr 0.122 0.147 0.185 0.215 0.256 0.289 0.324 0.360 0.411 0.451
(0.113-0.132) (0.136-0.159) (0.171-0.200) (0.198-0.233) (0.235-0.277) (0.265-0.313) (0.296-0.351) (0.328-0.391) (0.371-0.446) (0.406-0.490)
2-day 0.071 0.086 0.108 0.125 0.148 ' 0.167 0.186 0.207 r 0.235 0.258
(0.066-0.077) (0.080-0.094) (0.100-0.117) (0.115-0.135) (0.136-0.160) (0.153-0.181) (0.170-0.202) (0.188-0.225) (0.212-0.256) (0.231-0.281)
3-day 0.050 0.061 0.075 0.087 0.103 0.116 0.130 0.144 0.163 0.179
(0.047-0.054) (0.056-0.066) (0.070-0.082) (0.080-0.094) (0.095-0.112) (0.107-0.126) (0.119-0.140) (0.131-0.156) (0.148-0.177) (0.161-0.195)
4-day 0.040 0.048 0.059 0.068 0.081 0.091 0.101 0.112 0.127 0.139
(0.037-0.043) (0.044-0.052) (0.055-0.064) (0.063-0.074) (0.074-0.087) (0.084-0.098) (0.093-0.109),(0.102-0.121) (0.116-0.138) (0.126-0.151)
7-day 0.026 0.031 0.038 0.044 0.052 0.058 0.064 0.071 0.080 0.087
(0.024-0.028) (0.029-0.034) (0.036-0.041) (0.041-0.047) (0.048-0.055) (0.053-0.062) (0.059-0.069) (0.065-0.076) (0.073-0.086) (0.080-0.094)
10-day 0.021 0.025 0.030 0.034 0.040 0.044 0.048 0.053 0.059 0.064
(0.020-0.022) (0.023-0.027) (0.028-0.032) (0.032-0.037) (0.037-0.042) (0.041-0.047) (0.045-0.052) (0.049-0.057) (0.054-0.064) (0.059-0.069)
20-day 0.014 0.016 0.019 0.022 0.025 0.028 0.030 0.033 0.036 0.039
(0.013-0.015) (0.015-0.017) (0.018-0.021) (0.020-0.023) (0.023-0.027) (0.026-0.030) (0.028-0.032) (0.031-0.035) (0.034-0.039) (0.036-0.042)1
30-day 0.011 0.013 0.015 0.017 0.020 0.021 0.023 0.025 0.027 0.029
(0.011-0.012) (0.012-0.014) (0.015-0.016) (0.016-0.018) (0.018-0.021) (0.020-0.023) (0.022-0.025) (0.023-0.026) (0.025-0.029) (0.027-0.031)
45-day 0.009 0.011 0.013 0.014 0.016 0.017 0.018 0.019 0.021 0.022
(0.009-0.010) (0.010-0.012) (0.012-0.013) (0.013-0.015) (0.015-0.016) (0.016-0.018) (0.017-0.019) (0.018-0.020) (0.020-0.022) (0.021-0.023)
60-day 0.008 0.010 0.011 0.012 0.013 0.014 0.015 0.016 0.018 0.018
(0.008-0.009) (0.009-0.010) (0.011-0.012) (0.011-0.013) (0.013-0.014) (0.014-0.015) (0.015-0.016) (0.015-0.017) (0.017-0.018) (0.017-0.019)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates(for
a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not
checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
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PF graphical
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=35.0208&Ion=-80.7218&data=intensity&units=english&series=pds 1/4