SW3170802_Stormwater Report_20171013

TABLE OF CONTENTS

PROJECT NARRATIVE Page 1 -2

STORM DRAINAGE CALCULATIONS Pages 3-55
• RAINFALL INTENSITIES TABLE Pages 4-5
• SURFACE FLOW RUNOFF HYDROLOGY CALCULATIONS Pages 6-11
• STORM DRAINAGE PIPE CALCULATIONS Pages 12-18
• TC CALCULATIONS Pages 19-21
• CULVERT CALCULATIONS Pages 22-38
• GUTTER SPREAD CALCULATIONS Pages 39-41
• DROP INLET CALCULATIONS Pages 42-43
• FES CALCULATIONS Pages 44-55

SWALE CALCULATIONS Pages 56-71
• NAG SWALE CALCULATIONS Pages 56-71

EROSION CONTROL CALCULATIONS Pages 72-81
• SEDIMENT BASINS CALCULATIONS Pages 72-81

BMP DETENTION & WATER QUALITY CALCULATIONS Pages 82-148
• NARATIVE AND ANALYSIS SUMMARY TABLE Pages 83
• BMP CALCULATIONS Pages 84-95
• PONDPAK Pages 96-148

Project Narrative

Project Description
The project site is located in the Town of Weddington, Union County N.C. and is an approximately 50 acre parcel
along Weddington-Matthews Road (S.R. 1344). The proposed project consists of thirtyfive (35) single family
residential units, driveway access road and two (2) BMP’s designed in accordance with Town of Weddington,
NCDEQ and NCDOT requirements. The project area drains to unknown tributary that eventually flows to Sixmile
Creek and is subject to the site specific Water Quality Management requirements prescribed by the N.C. Division
of Environmental Quality (NCDEQ).

NCDEQ requirements that have been met in the design of this project include the control and treatment of the
difference in the stormwater runoff from the pre-development and post-development conditions for the one-year,
24-hour storm, with structural stormwater controls that promote infiltration of flows and groundwater recharge, if
practicable based upon soil conditions.

The rainfall amounts used in the analysis of this project were obtained from current data from NOAA.

Structural stormwater controls have been provided to meet the following minimum requirements:

a. Remove an 85 percent average annual amount of Total Suspended Solids
b. Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours, for detention
ponds.
c. Discharge the storage volume at a rate equal or less than the pre-development discharge rate for the
one-year 24-hour storm.
d. Meet design of Stormwater Management Measures set forth in 15A NCAC 02H .1008.

Additional stormwater management measures have been provided for this project as required by Town of
Weddington to include the following:

a. In accordance with Town of Weddington , the post developed discharge rate at the property boundary
is less than or equal to the pre development rate for the (1,2,10,25,50 & 100) one, two, ten,
twentyfive, fifty and one hundred year storm events.

Natural Resources Inventory
The parcel is covered in approximately 65% woods and 35% grass fields. Wetlands and Environmental Planning
Group has performed a wetland and riparian buffer delineation and as a result identified two jurisdictional
wetland, one along the east side and one on the west portion of the property and also identified two jurisdictional
streams that bisect the property.

Existing on-site slopes range from 2 to 20 percent on average and existing soil types on site are Cecil
(Hydrologic Group B) and Helena (Hydrologic group C). Soil and Forestry Services of the Carolinas Summit has
performed on-site geotechnical testing to establish hydraulic conductivity of on-site soils for suitability for
infiltration devices along with the vertical location of Seasonal High Water Table at the location of the proposed
BMP 1 & 2.

Existing and Proposed Drainage Patterns
Proposed drainage patterns to the proposed on-site BMP are maintaining existing drainage patterns to the
maximum extent practicable as need to create a balanced distribution of storm water flow thru BMP 1 and BMP 2
in a consistent manner with existing flows.

Proposed BMP Summary

Proposed BMP #1 (Sand Filter)
BMP #1 (Sand Filter) has been designed per the NCDEQ requirements of the contributing drainage area
(8.75 ac.) to meet 85% TSS removal, 25% TN and 40% TP removal targets. The SHWT was established as
required to establish the minimum vertical separations as outlined by the NCDEQ requirements. BMP #1 meets
or exceeds the following requirements:

• The control and treatment of the difference in the stormwater runoff from the pre-development and post-
development conditions for the one-year, 24-hour storm.
• Removal of an 85 percent average annual amount of Total Suspended Solids (85% TSS removal), 25%
TN (min) and 40% TP (min) removals
• Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours.
• Discharge the storage volume at a rate equal or less than the pre-development
discharge rate for the one-year, 24-hour storm
• Meet design of Stormwater Management Measures set forth in 15A NCAC 02H .1008.
• The post developed discharge rate at the property boundary is less than or equal to the pre development
rate for the (1,2,10,25,50 & 100) one, two, ten, twentyfive, fifty and one hundred year storm events.

Proposed BMP #2 (Wet Pond)
BMP #2 (Wet Pond) has been designed per the NCDEQ requirements of the contributing drainage area
(16.488 ac.) to meet 85% TSS removal, 25% TN and 40% TP removal targets. The SHWT was established as
required to establish the minimum vertical separations as outlined by the NCDEQ requirements. BMP #2 meets
or exceeds the following requirements:

• The control and treatment of the difference in the stormwater runoff from the pre-development and post-
development conditions for the one-year, 24-hour storm.
• Removal of an 85 percent average annual amount of Total Suspended Solids (85% TSS removal), 25%
TN (min) and 40% TP (min) removals
• Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours.
• Discharge the storage volume at a rate equal or less than the pre-development
discharge rate for the one-year, 24-hour storm
• Meet design of Stormwater Management Measures set forth in 15A NCAC 02H .1008.
• The post developed discharge rate at the property boundary is less than or equal to the pre development
rate for the (1,2,10,25,50 & 100) one, two, ten, twentyfive, fifty and one hundred year storm events.

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

STORM DRAINAGE CALCULATIONS

Note: Refer to Construction Document sheet C6.0 for drainage area maps.

HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Weddington NOTE: 10‐YR. INTENSITY OF 7.44 USED FOR CLOSED DRAINAGE SYSTEM AND
8.28 USED FOR 25‐YR INTENSITY IN CULVERT AND ROAD CROSSING  LOCATIONS.
Storm Drainage Hydrology
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #1
CB 1G 0.11 0.11 0.65 8.28 0.59 0.59
CB 1F 0.24 0.35 0.75 7.44 1.34 16.01 1G & 2A
CB 1E 0.11 0.46 0.75 7.44 0.61 16.62 1F
CB 1D 0.14 0.60 0.75 7.44 0.78 18.75 1E & 3A
CB 1C 0.09 0.69 0.75 8.28 0.56 34.30 1D, 4A & 6A
CB 1B 0.11 0.80 0.65 7.44 0.53 34.83 1C
FES 2A 3.44 3.44 0.55 7.44 14.08 14.08
CB 3A 0.25 0.25 0.65 8.28 1.35 1.35
CB 4D 0.25 0.25 0.65 8.28 1.35 1.35
CB 4C 0.21 0.46 0.75 7.44 1.17 2.52 4D
CB 4B 0.38 0.84 0.50 7.44 1.41 3.93 4C
CB 4A 0.09 0.93 0.75 7.44 0.50 6.32 4B & 5A
CB 5A 0.35 0.35 0.65 8.28 1.88 1.88
FES 6A 2.12 2.12 0.55 7.44 8.68 8.68
Network #1 Total: 34.83
HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #2
CB 7P 0.22 0.22 0.65 8.28 1.18 1.18
CB 7N 0.61 0.83 0.60 7.44 2.72 3.91 7P
CB 7M 0.31 1.14 0.60 7.44 1.38 5.29 7N
CB 7L 0.32 1.46 0.60 7.44 1.43 6.72 7M, 8A & 9A
CB 7K 0.31 1.77 0.60 7.44 1.38 16.14 7L
CB 7J 0.57 2.34 0.60 7.44 2.54 18.68 7K
CB 7H 0.30 2.64 0.60 7.44 1.34 20.02 7J
CB 7G 0.39 2.73 0.60 7.44 1.74 27.53 7H & 10A
CB 7F 0.61 3.34 0.60 8.28 3.03 30.56 7J
CB 7E 0.12 3.46 0.65 7.44 0.58 44.75 7F & 11A
CB 7D 0.09 3.55 0.75 7.44 0.50 45.26 7E
CB 7C 0.24 3.79 0.75 7.44 1.34 46.60 7D
DI 7B 0.22 4.01 0.50 7.44 0.82 47.41
DI 8A 1.90 1.90 0.50 7.44 7.07 7.07
CB 9A 0.18 0.18 0.65 8.28 0.97 0.97
CB 10B 0.63 0.63 0.60 8.28 3.13 3.13
CB 10A 0.53 0.53 0.60 8.28 2.63 5.76 10B
FES 11D 0.78 0.78 0.55 7.44 3.19 3.19
CB 11C 0.26 1.04 0.65 8.28 1.40 4.59 11D
CB 11B 0.18 1.22 0.65 7.44 0.87 13.23 11C & 12A
CB 11A 0.08 1.30 0.65 7.44 0.39 13.62 11B
FES 12A 2.32 2.32 0.45 7.44 7.77 7.77
Network #2 Total: 47.41
HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #3
HW 14B‐1 0.12 0.12 0.50 4.23 0.25 9.20 1/2 OF 17A
HW 14B‐2 0.12 0.12 0.50 4.23 0.25 9.20 1/2 OF 17A
DI 17D 7.56 7.56 0.50 4.23 15.98 15.98
JB 17C 0.00 7.56 0.60 4.23 0.00 15.98 17D
JB 17B 0.00 7.56 0.60 4.23 0.00 15.98 17C
FES 17A/14D 0.91 8.47 0.50 4.23 1.92 17.90 17A
HW 15B 18.43 18.43 0.50 4.90 45.18 45.18
HW 16D 13.32 13.32 0.50 3.81 25.36 35.27
JB 16C 0.00 13.32 0.50 3.81 0.00 0.00 16C
JB 16B 0 13.32 0.50 3.81 0.00 0.00 16B
Note: Additional 9.91 cfs added to HW 16D from water tank incase of emergency spill.
HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Weddington NOTE: CHECK DRAINAGE SYSTEM USING 100‐YR. INTENSITY OF 9.31
Storm Drainage Hydrology
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #1
CB 1G 0.11 0.11 0.65 9.31 0.67 0.67
CB 1F 0.24 0.35 0.75 9.31 1.68 19.96 1G & 2A
CB 1E 0.11 0.46 0.75 9.31 0.77 20.72 1F
CB 1D 0.14 0.60 0.75 9.31 0.98 23.21 1E & 3A
CB 1C 0.09 0.69 0.75 9.31 0.63 42.19 1D, 4A & 6A
CB 1B 0.11 0.80 0.65 9.31 0.67 42.86 1C
FES 2A 3.44 3.44 0.55 9.31 17.61 17.61
CB 3A 0.25 0.25 0.65 9.31 1.51 1.51
CB 4D 0.25 0.25 0.65 9.31 1.51 1.51
CB 4C 0.21 0.46 0.75 9.31 1.47 2.98 4D
CB 4B 0.38 0.84 0.50 9.31 1.77 4.75 4C
CB 4A 0.09 0.93 0.75 9.31 0.63 7.49 4B & 5A
CB 5A 0.35 0.35 0.65 9.31 2.12 2.12
FES 6A 2.12 2.12 0.55 9.31 10.86 10.86
Network #1 Total: 42.86
HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #2
CB 7P 0.22 0.22 0.65 9.31 1.33 1.33
CB 7N 0.61 0.83 0.60 9.31 3.41 4.74 7P
CB 7M 0.31 1.14 0.60 9.31 1.73 6.47 7N
CB 7L 0.32 1.46 0.60 9.31 1.79 8.26 7M, 8A & 9A
CB 7K 0.31 1.77 0.60 9.31 1.73 19.92 7L
CB 7J 0.57 2.34 0.60 9.31 3.18 23.11 7K
CB 7H 0.30 2.64 0.60 9.31 1.68 24.78 7J
CB 7G 0.39 2.73 0.60 9.31 2.18 33.44 7H & 10A
CB 7F 0.61 3.34 0.60 9.31 3.41 36.85 7J
CB 7E 0.12 3.46 0.65 9.31 0.73 54.44 7F & 11A
CB 7D 0.09 3.55 0.75 9.31 0.63 55.06 7E
CB 7C 0.24 3.79 0.75 9.31 1.68 56.74 7D
DI 7B 0.22 4.01 0.50 9.31 1.02 57.76
DI 8A 1.90 1.90 0.50 9.31 8.84 8.84
CB 9A 0.18 0.18 0.65 9.31 1.09 1.09
CB 10B 0.63 0.63 0.60 9.31 3.52 3.52
CB 10A 0.53 0.53 0.60 9.31 2.96 6.48 10B
FES 11D 0.78 0.78 0.55 9.31 3.99 3.99
CB 11C 0.26 1.04 0.65 9.31 1.57 5.57 11D
CB 11B 0.18 1.22 0.65 9.31 1.09 16.38 11C & 12A
CB 11A 0.08 1.30 0.65 9.31 0.48 16.86 11B
FES 12A 2.32 2.32 0.45 9.31 9.72 9.72
Network #2 Total: 57.76
HYDROLOGIC CALCULATIONS FOR CLOSED STORM SYSTEM DRAINAGE DESIGN
Structure
Drainage 
Area (acres)
Accumulated 
Drainage Area 
Runoff 
Coefficient Intesity Flow (cfs)
Accumulated 
Flow (cfs)
Contributing 
Structure
Network #3
HW 14B‐1 0.12 0.12 0.50 4.88 0.29 10.62
HW 14B‐2 0.12 0.12 0.50 4.88 0.29 10.62
DI 17D 7.56 7.56 0.50 4.88 18.44 18.44
JB 17C 0.00 7.56 0.60 4.88 0.00 18.44 17D
JB 17B 0.00 7.56 0.60 4.88 0.00 18.44 17C
FES 17A 0.91 8.47 0.50 4.88 2.22 20.66 17A
HW 15B 18.43 18.43 0.50 5.56 51.22 51.22
HW 16D 13.32 13.32 0.50 4.43 29.52 29.52
JB 16C 0.00 13.32 0.50 4.43 0.00 0.00 16C
JB 16B 0 13.32 0.50 4.43 0.00 0.00 16B
TR55 Tc Worksheet
Hydraflow Express by Intelisolve
Mod Rational
<Name>
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 150.0 0.0 0.0
Two-year 24-hr precip. ((in)) = 3.12 0.00 0.00
Land slope (%) = 2.50 0.00 0.00
Travel Time (min) = 18.28 + 0.00 + 0.00 = 18.28
Shallow Concentrated Flow
Flow length (ft) = 234.00 0.00 0.00
Watercourse slope (%) = 3.79 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 3.14 0.00 0.00
Travel Time (min)
= 1.24 + 0.00 + 0.00 = 1.24
Channel Flow
X sectional flow area ((sqft)) = 18.00 0.00 0.00
Wetted perimeter ((ft)) = 18.44 0.00 0.00
Channel slope (%) = 2.26 0.00 0.00
Manning's n-value = 0.035 0.015 0.015
Velocity (ft/s) = 6.30 0.00 0.00
Flow length (ft) = 869.0 0.0 0.0
Travel Time (min) = 2.2999760.00+0 +0 =2.30
Total Travel Time, Tc ..............................................................................22.00 min
TR55 Tc Worksheet
Hydraflow Express by Intelisolve
Rational
Time of Concentration (Tc) to DI-17D
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 150.0 0.0 0.0
Two-year 24-hr precip. ((in)) = 3.12 0.00 0.00
Land slope (%) = 1.00 0.00 0.00
Travel Time (min) = 26.38 + 0.00 + 0.00 = 26.38
Shallow Concentrated Flow
Flow length (ft) = 1197.00 0.00 0.00
Watercourse slope (%) = 1.30 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 1.84 0.00 0.00
Travel Time (min)
= 10.84 + 0.00 + 0.00 = 10.84
Channel Flow
X sectional flow area ((sqft)) = 0.00 0.00 0.00
Wetted perimeter ((ft)) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) = 0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0 + 0 + 0 = 0.00
Total Travel Time, Tc ..............................................................................37.00 min
TR55 Tc Worksheet
Hydraflow Express by Intelisolve
Mod Rational
<Name>
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 150.0 0.0 0.0
Two-year 24-hr precip. ((in)) = 3.12 0.00 0.00
Land slope (%) = 1.50 0.00 0.00
Travel Time (min) = 22.43 + 0.00 + 0.00 = 22.43
Shallow Concentrated Flow
Flow length (ft) = 835.00 0.00 0.00
Watercourse slope (%) = 1.93 0.00 0.00
Surface description = Unpaved Paved Paved
Average velocity (ft/s) = 2.24 0.00 0.00
Travel Time (min)
= 6.21 + 0.00 + 0.00 = 6.21
Channel Flow
X sectional flow area ((sqft)) = 0.00 0.00 0.00
Wetted perimeter ((ft)) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) = 0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0 + 0 + 0 = 0.00
Total Travel Time, Tc ..............................................................................29.00 min
HY-8 Culvert Analysis Report
Crossing Discharge Data
CULVERT 14 – 24” DOUBLE BARREL RCP UNDER DORNOCH DRIVE
Discharge Selection Method: Specify Minimum, Design, and Maximum Flow
Minimum Flow: 0 cfs
Design Flow: 18.4 cfs (25-Yr. Storm)
Maximum Flow: 21.24 cfs (100-Yr Storm)
Table 1 - Summary of Culvert Flows at Crossing: Crossing 1

Headwater Elevation
(ft) Total Discharge (cfs) Culvert 14 Discharge
(cfs) Roadway Discharge
(cfs) Iterations
703.00 0.00 0.00 0.00 1
703.48 2.12 2.12 0.00 1
703.69 4.25 4.25 0.00 1
703.85 6.37 6.37 0.00 1
703.99 8.50 8.50 0.00 1
704.14 10.62 10.62 0.00 1
704.28 12.74 12.74 0.00 1
704.41 14.87 14.87 0.00 1
704.53 16.99 16.99 0.00 1
704.61 18.40 18.40 0.00 1
704.76 21.24 21.24 0.00 1
706.32 44.69 44.69 0.00 Overtopping
Rating Curve Plot for Crossing: Crossing 1

Table 2 - Culvert Summary Table: Culvert 14

HW/D = 1.605 / 2 = 0.80 FT.
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth (ft)
Outlet
Control
Depth (ft)
Flow
Type
Normal
Depth (ft)
Critical
Depth (ft)
Outlet
Depth (ft)
Tailwater
Depth (ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
0.00 0.00 703.00 0.000 0.000 0-NF 0.000 0.000 1.000 1.000 0.000 0.000
2.12 2.12 703.48 0.480 0.0* 1-JS1t 0.250 0.351 1.000 1.000 0.654 0.000
4.25 4.25 703.69 0.686 0.0* 1-JS1t 0.350 0.501 1.000 1.000 1.308 0.000
6.37 6.37 703.85 0.848 0.0* 1-JS1t 0.428 0.621 1.000 1.000 1.963 0.000
8.50 8.50 703.99 0.990 0.0* 1-S2n 0.494 0.720 0.494 1.000 6.797 0.000
10.62 10.62 704.14 1.141 0.0* 1-S2n 0.554 0.809 0.554 1.000 7.241 0.000
12.74 12.74 704.28 1.279 0.0* 1-S2n 0.609 0.893 0.632 1.000 7.227 0.000
14.87 14.87 704.41 1.407 0.0* 1-S2n 0.660 0.969 0.688 1.000 7.497 0.000
16.99 16.99 704.53 1.528 0.0* 1-S2n 0.708 1.038 0.741 1.000 7.759 0.000
18.40 18.40 704.61 1.605 0.084 1-S2n 0.739 1.081 0.774 1.000 7.911 0.000
21.24 21.24 704.76 1.757 0.275 1-S2n 0.800 1.165 0.839 1.000 8.213 0.000
* Full Flow Headwater elevation is below inlet invert.
********************************************************************************
Straight Culvert
Inlet Elevation (invert): 703.00 ft, Outlet Elevation (invert): 701.68 ft
Culvert Length: 88.04 ft, Culvert Slope: 0.0150
********************************************************************************
Culvert Performance Curve Plot: Culvert 14

Water Surface Profile Plot for Culvert: Culvert 14

Site Data - Culvert 14
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 703.00 ft
Outlet Station: 88.03 ft
Outlet Elevation: 701.68 ft
Number of Barrels: 2
Culvert Data Summary - Culvert 14
Barrel Shape: Circular
Barrel Diameter: 2.00 ft
Barrel Material: Concrete
Embedment: 0.00 in
Barrel Manning's n: 0.0120
Culvert Type: Straight
Inlet Configuration: Square Edge with Headwall
Inlet Depression: None
Table 3 - Downstream Channel Rating Curve (Crossing: Crossing 1)
Tailwater Channel Data - Crossing 1
Tailwater Channel Option: Enter Constant Tailwater Elevation
Constant Tailwater Elevation: 702.68 ft
Roadway Data for Crossing: Crossing 1
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 100.00 ft
Crest Elevation: 706.32 ft
Roadway Surface: Paved
Roadway Top Width: 50.00 ft
Flow (cfs) Water Surface Elev (ft) Depth (ft)
0.00 702.68 1.00
2.12 702.68 1.00
4.25 702.68 1.00
6.37 702.68 1.00
8.50 702.68 1.00
10.62 702.68 1.00
12.74 702.68 1.00
14.87 702.68 1.00
16.99 702.68 1.00
18.40 702.68 1.00
21.24 702.68 1.00
Crossing Discharge Data
CULVERT 15B – 36” RCP UNDER GLENCOE DRIVE
Discharge Selection Method: Specify Minimum, Design, and Maximum Flow
Minimum Flow: 0 cfs
Design Flow: 45.18 cfs (25-Yr Storm)
Maximum Flow: 51.22 cfs (100-Yr Storm)
Table 4 - Summary of Culvert Flows at Crossing: Crossing 2

Headwater Elevation
(ft) Total Discharge (cfs) Culvert 15 Discharge
(cfs) Roadway Discharge
(cfs) Iterations
698.21 0.00 0.00 0.00 1
699.15 5.12 5.12 0.00 1
699.57 10.24 10.24 0.00 1
699.94 15.37 15.37 0.00 1
700.29 20.49 20.49 0.00 1
700.60 25.61 25.61 0.00 1
700.90 30.73 30.73 0.00 1
701.20 35.85 35.85 0.00 1
701.52 40.98 40.98 0.00 1
701.80 45.18 45.18 0.00 1
702.25 51.22 51.22 0.00 1
706.32 88.04 88.04 0.00 Overtopping
Rating Curve Plot for Crossing: Crossing 2

Table 5 - Culvert Summary Table: Culvert 15

HW/D = 3.59/3 = 1.20 FT.
Total
Discharge
(cfs)
Culvert
Discharge
(cfs)
Headwater
Elevation
(ft)
Inlet
Control
Depth (ft)
Outlet
Control
Depth (ft)
Flow
Type
Normal
Depth (ft)
Critical
Depth (ft)
Outlet
Depth (ft)
Tailwater
Depth (ft)
Outlet
Velocity
(ft/s)
Tailwater
Velocity
(ft/s)
0.00 0.00 698.21 0.000 0.000 0-NF 0.000 0.000 0.000 0.000 0.000 0.000
5.12 5.12 699.15 0.940 0.0* 1-S2n 0.378 0.705 0.394 1.033 9.010 3.426
10.24 10.24 699.57 1.355 0.0* 1-S2n 0.530 1.010 0.530 1.340 11.707 4.074
15.37 15.37 699.94 1.729 0.0* 1-S2n 0.647 1.247 0.696 1.560 11.906 4.509
20.49 20.49 700.29 2.076 0.0* 1-S2n 0.748 1.454 0.815 1.738 12.754 4.845
25.61 25.61 700.60 2.388 0.0* 1-S2n 0.839 1.629 0.925 1.890 13.345 5.123
30.73 30.73 700.90 2.686 0.0* 1-S2n 0.922 1.791 1.029 2.023 13.834 5.362
35.85 35.85 701.20 2.988 0.0* 1-S2n 1.000 1.943 1.127 2.144 14.278 5.573
40.98 40.98 701.52 3.307 0.0* 5-S2n 1.073 2.082 1.220 2.254 14.664 5.762
45.18 45.18 701.80 3.590 0.249 5-S2n 1.131 2.187 1.293 2.338 14.980 5.904
51.22 51.22 702.25 4.038 0.730 5-S2n 1.211 2.325 1.398 2.451 15.344 6.092
* Full Flow Headwater elevation is below inlet invert.
********************************************************************************
Straight Culvert
Inlet Elevation (invert): 698.21 ft, Outlet Elevation (invert): 694.83 ft
Culvert Length: 87.37 ft, Culvert Slope: 0.0387
********************************************************************************
Culvert Performance Curve Plot: Culvert 15

Water Surface Profile Plot for Culvert: Culvert 15

Site Data - Culvert 15
Site Data Option: Culvert Invert Data
Inlet Station: 0.00 ft
Inlet Elevation: 698.21 ft
Outlet Station: 87.30 ft
Outlet Elevation: 694.83 ft
Number of Barrels: 1
Culvert Data Summary - Culvert 15
Barrel Shape: Circular
Barrel Diameter: 3.00 ft
Barrel Material: Concrete
Embedment: 0.00 in
Barrel Manning's n: 0.0120
Culvert Type: Straight
Inlet Configuration: Square Edge with Headwall
Inlet Depression: None
Table 6 - Downstream Channel Rating Curve (Crossing: Crossing 2)
Tailwater Channel Data - Crossing 2
Tailwater Channel Option: Triangular Channel
Side Slope (H:V): 1.40 (_:1)
Channel Slope: 0.0270
Channel Manning's n: 0.0400
Channel Invert Elevation: 694.83 ft
Roadway Data for Crossing: Crossing 2
Roadway Profile Shape: Constant Roadway Elevation
Crest Length: 100.00 ft
Crest Elevation: 706.32 ft
Roadway Surface: Paved
Roadway Top Width: 50.00 ft

Flow (cfs) Water Surface
Elev (ft) Depth (ft) Velocity (ft/s) Shear (psf) Froude Number
0.00 694.83 0.00 0.00 0.00 0.00
5.12 695.86 1.03 3.43 1.74 0.84
10.24 696.17 1.34 4.07 2.26 0.88
15.37 696.39 1.56 4.51 2.63 0.90
20.49 696.57 1.74 4.85 2.93 0.92
25.61 696.72 1.89 5.12 3.18 0.93
30.73 696.85 2.02 5.36 3.41 0.94
35.85 696.97 2.14 5.57 3.61 0.95
40.98 697.08 2.25 5.76 3.80 0.96
45.18 697.17 2.34 5.90 3.94 0.96
51.22 697.28 2.45 6.09 4.13 0.97

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

GUTTER SPREAD
CALCULATIONS

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

DROP INLET
CALCULATIONS

DROP INLET CALCULATIONS9/19/2017Rational MethodProject: Weddington GlenDesign Objective: PROVIDE 6" FREEBOARD AT INLET FOR DESIGN STORM (10 YR), DI-17D (USE 25 YR)A B A+BStructure Area Tc ( t ) Intensity ( i ) Flow Orifice Weir Depth of Water Rim El. Water El H.P. El.Acerage (Min.) (in/hr) cfs(ft) ft)over D.I. (ft)(ft) (ft.) (ft)DI-7B 0.22 0.55.007.440.820.00 0.080.08697.00 697.08 698.50 O.K.DI-8A 1.9 0.55.007.447.070.16 0.330.33711.59 711.92 714.00 O.K.DI-17D 7.56 0.529.004.2315.990.82 0.580.82713.00 713.82 716.00 O.K.Coeff.P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\Storm Drainage\16157-DI.xls

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

FES CALCULATIONS

21Minimum Tailwater Conditions d (in.) Q (cfs) 1BMP OS#1 36 23.32 »2BMP OS#2 42 18.35 »»»»Description of Apron16'L x19'W x 18"D CLASS B APRON22'L x 25.5'W x 18"D CLASS B APRONP:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\Storm Drainage\16157-fes.xls
THE ISAACS GROUP
FLARED END SECTION RIP RAP APRON DESIGN
WEDDINGTON GLEN SUBDIVISION
UNION COUNTY, NORTH CAROLINA
Minimum Tailwater Conditions
D = OUTLET PIPE DIAMETER (in)
Do =OUTLET PIPE DIAMETER (ft)
La = LENGTH OF APRON (ft) [FROM FIGURE 8-1, CHARLOTTE STORMWATER DESIGN MANUAL] (MINIMUM L a = 10)
W = WIDTH OF APRON (ft) [W = D o + La]
Q = FLOW (cfs)
d50 = STONE SIZE (ft) [FROM FIGURE 8-1, CHARLOTTE STORMWATER DESIGN MANUAL]
BMP #1 BMP #2
D 36 42
Q 23.32 18.35
Do 3 3.5
3Do 9 10.5
La 16 22
W 19 25.5
d50 0.75 0.5
*MIN. APRON SIZE NOT TO BE LESS THAN 8'Wx11'Lx18"D CLASS B APRON
VII VIIIMaximum Tailwater Condit I,VI II,III,IV,V d (in.) Q (cfs)IFES 14A 24 18.40 »IIFES 15A 36 48.00 »IIIFES 16A 30 29.02 »IVFES 1A 30 34.83 »VFES 7A 36 40.55 »VIFES 17A 24 17.90 »VIIFES 18A 18 7.40 »VIIIFES 19A 15 4.95 » 11'L x8'W x 18"D CLASS B APRON13'L x 8'W x 18"D CLASS B APRON13'L x 8'W x 18"D CLASS B APRONDescription of Apron11'L x 8'W x 18"D CLASS B APRON13'L x8'W x 18"D CLASS B APRON13'L x 8'W x 18"D CLASS B APRON11'L x8'W x 18"D CLASS B APRON11'L x8'W x 18"D CLASS B APRONP:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\Storm Drainage\16157-fes.xls
THE ISAACS GROUP
FLARED END SECTION RIP RAP APRON DESIGN
WEDDINGTON ROAD SUBDIVISION
UNION COUNTY, NORTH CAROLINA
Maximum Tailwater Conditions
D = OUTLET PIPE DIAMETER (in)
Do =OUTLET PIPE DIAMETER (ft)
La = LENGTH OF APRON (ft) [FROM FIGURE 8-2, CHARLOTTE STORMWATER DESIGN MANUAL] (MINIMUM La = 10)
W = WIDTH OF APRON (ft) [W = Do + 0.4 La]
Q = FLOW (cfs)
d50 = STONE SIZE (ft) [FROM FIGURE 8-2, CHARLOTTE STORMWATER DESIGN MANUAL]
FES 14A FES 15A FES 16A FES 1A FES 7A FES 17A FES 18A FES 19A
D 24 36 30 30 36 24 18 15
Q 18.40 48.00 29.02 34.83 40.55 17.90 7.40 4.95
Do 2 3 2.5 2.5 3 2 1.5 1.25
3Do 6 9 7.5 7.5 9 6 4.5 3.75
La 13 13 13 13 13 11 11 11
W 7.2 8.2 7.7 7.7 8.2 6.4 5.9 5.65
d50 0.6 0.5 0.5 0.6 0.5 0.5 0.5 0.5
*MIN. APRON SIZE NOT TO BE LESS THAN 8'Wx10'Lx18"D CLASS B APRON

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

SWALE CALCULATIONS

North American Green Erosion Control Materials Design Software was used to determine the
following:

• The normal depth of the swale under poorly maintained grass depth conditions.
• The vegetation stability when the grass is properly maintained by a homeowner.
• The temporary liner stability before the site is stabilized.

The drainage areas and swale slopes were determined from the construction drawings. The
retardance class was changed to D (grass depth 2-6 inches) for a properly maintained grass
swale to determine vegetation stability. The normal water depth was determined by using a
unreinforced vegetation matting type with a retardance class of B (grass depth 12-24 inches)
for an under or none maintained grass swale for use with the freeboard calculations. Then the
swale was changed to unvegetated with a S75 temporary liner to determine liner stability.
Swales that were unstable for any reason either were widened and/or lined with different
temporary liners. If the calculations of the temporary linear showed a velocity of less than 2
fps during a 10 year storm event then the temporary linear was removed.

“Each swale cross section was analyzed using the largest contributing flow”
SWALE CALCULATIONS
Weddington Glen Subdivision NOTE: 10‐YR. INTENSITY OF 7.44 USED FOR SWALE
Storm Drainage Hydrology
Swale to 
Structure
Drainage 
Area (acres)
Runoff 
Coefficient Intesity Flow (cfs) SLOPE TYPE LINER
2A‐1 1.44 0.55 7.44 5.89 2.00% A S75
2A‐2 1.72 0.55 7.44 7.04 5.50% B SC150
2A‐3 2.52 0.55 7.44 10.31 2.00% A S75
2A‐4 0.33 0.55 7.44 1.35 2.50% A S75
6A‐1 0.95 0.56 7.44 3.96 5.00% A S75
6A‐2 1.35 0.54 7.44 5.42 2.00% A S75
6A‐3 0.77 0.55 7.44 3.15 5.25% A S75
8A‐1 0.21 0.50 7.44 0.78 6.50% A S75
8‐A2 1.20 0.50 7.44 4.46 2.50% A S75
8A‐3 1.9 0.50 7.44 7.07 2.00% A S75
7B‐1 0.22 0.50 7.44 0.82 2.00% A S75
2A 1.33 0.55 7.44 5.44 6.00% B SC150
2B 1.99 0.55 7.44 8.14 3.00% A S75
2C 0.55 0.55 7.44 2.25 2.00% A S75
11D‐1 0.78 0.60 7.44 3.48 3.00% A S75
12A‐1 2.32 0.40 7.44 6.90 1.50% A S75
14D‐2 7.44 17.90 1.00% C S75
SWALE TYPE WITH MAXIMUM SLOPE AND FLOWS USED IN SIZING SWALE.
SWALE: TYPE A TYPE B TYPE C
SWALE TO FES 12A
SWALE TO FES 2A
SWALE TO FES 6A
SWALE TO DI 8A
SWALE TO DI 7B
SWALE TO BMP 2
SWALE TO FES 11D
SWALE TO FES 14D
SWALE CALCULATIONS
Weddington Glen Subdivision NOTE: 100‐YR. INTENSITY OF 9.31 USED FOR SWALE
Storm Drainage Hydrology
Swale to 
Structure
Drainage 
Area (acres)
Runoff 
Coefficient Intesity Flow (cfs) SLOPE TYPE LINER
2A‐1 1.44 0.55 9.31 7.37 2.00% A S75
2A‐2 1.72 0.55 9.31 8.81 5.50% B SC150
2A‐3 2.52 0.55 9.31 12.90 2.00% A S75
2A‐4 0.33 0.55 9.31 1.69 2.50% A S75
6A‐1 0.95 0.56 9.31 4.95 5.00% A S75
6A‐2 1.35 0.54 9.31 6.79 2.00% A S75
6A‐3 0.77 0.55 9.31 3.94 5.25% A S75
8A‐1 0.21 0.50 9.31 0.98 6.50% A S75
8‐A2 1.20 0.50 9.31 5.59 2.50% A S75
8A‐3 1.9 0.50 9.31 8.84 2.00% A S75
7B‐1 0.22 0.50 9.31 1.02 2.00% A S75
2A 1.33 0.55 9.31 6.81 6.00% B SC150
2B 1.99 0.55 9.31 10.19 3.00% A S75
2C 0.55 0.55 9.31 2.82 2.00% A S75
11D‐1 0.78 0.60 9.31 4.36 3.00% A S75
12A‐1 2.32 0.40 9.31 8.64 1.50% A S75
14D‐2 9.31 20.66 1.00% C S75
SWALE TYPE WITH MAXIMUM SLOPE AND FLOWS USED IN SIZING SWALE.
SWALE: TYPE A TYPE B TYPE C
SWALE TO FES 12A
SWALE TO FES 2A
SWALE TO FES 6A
SWALE TO DI 8A
SWALE TO DI 7B
SWALE TO BMP 2
SWALE TO FES 11D
SWALE TO FES 14D
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 23 2017
SWALE 2A-2 (TYPE B)
Trapezoidal
Bottom Width (ft) = 2.00
Side Slopes (z:1) = 3.00, 3.00
Total Depth (ft) = 2.00
Invert Elev (ft) = 1.00
Slope (%) = 5.50
N-Value = 0.100
Calculations
Compute by: Known Q
Known Q (cfs) = 8.81
Highlighted
Depth (ft) = 0.86
Q (cfs) = 8.810
Area (sqft) = 3.94
Velocity (ft/s) = 2.24
Wetted Perim (ft) = 7.44
Crit Depth, Yc (ft) = 0.63
Top Width (ft) = 7.16
EGL (ft) = 0.94
0 2 4 6 8 10 12 14 16 18
Elev (ft)Depth (ft)Section
0.50 -0.50
1.00 0.00
1.50 0.50
2.00 1.00
2.50 1.50
3.00 2.00
3.50 2.50
4.00 3.00
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Wednesday, Aug 23 2017
SWALE 2A-3 (TYPE A)
Trapezoidal
Bottom Width (ft) = 2.00
Side Slopes (z:1) = 3.00, 3.00
Total Depth (ft) = 2.00
Invert Elev (ft) = 1.00
Slope (%) = 2.00
N-Value = 0.100
Calculations
Compute by: Known Q
Known Q (cfs) = 12.90
Highlighted
Depth (ft) = 1.29
Q (cfs) = 12.90
Area (sqft) = 7.57
Velocity (ft/s) = 1.70
Wetted Perim (ft) = 10.16
Crit Depth, Yc (ft) = 0.76
Top Width (ft) = 9.74
EGL (ft) = 1.34
0 2 4 6 8 10 12 14 16 18
Elev (ft)Depth (ft)Section
0.50 -0.50
1.00 0.00
1.50 0.50
2.00 1.00
2.50 1.50
3.00 2.00
3.50 2.50
4.00 3.00
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Sep 19 2017
<Name>
Trapezoidal
Bottom Width (ft) = 2.00
Side Slopes (z:1) = 1.50, 1.50
Total Depth (ft) = 2.78
Invert Elev (ft) = 705.90
Slope (%)= 1.00
N-Value = 0.030
Calculations
Compute by:Known Q
Known Q (cfs) = 20.66
Highlighted
Depth (ft)= 1.28
Q (cfs)= 20.66
Area (sqft)= 5.02
Velocity (ft/s)= 4.12
Wetted Perim (ft) = 6.62
Crit Depth, Yc (ft) = 1.13
Top Width (ft)= 5.84
EGL (ft)= 1.54
0 2 4 6 8 10 12 14 16
Elev (ft)Depth (ft)Section
704.00 -1.90
705.00 -0.90
706.00 0.10
707.00 1.10
708.00 2.10
709.00 3.10
Reach (ft)

WEDDINGTON GLEN SUBDIVISION

WEDDINGTON, NORTH CAROLINA

EROSION CONTROL CALCULATIONS

Narrative:

Erosion control measures have been designed in accordance with Town of Weddington
and North Carolina Department of Environmental Quality requirements and standards.
Erosion control is maintained on the site via silt fence, diversion ditches, storm
drainage inlet protection and riser and skimmer basins. The sediment pond and
skimmer have been sized for the 10 year storm event.

The ISAACS GROUP Date 9/18/2017
Weddington Glen Subdivision Weddington, North Carolina
Skimmer Basin Design & Calculations (BASIN #1)
Time of Concentration Calculation
Peak Flow Calculation
Total Time of Concentration, Tc 5.00 (min.)
i , 10 yr. Rainfall Intensity (table 2.3)7.44 (in./hr.)
C, Rainfall Runoff Coefficient 0.45
AD, Drainage Area to Structure (Pre-Developed)235,031 (sq. ft.) 5.40 (ac.)
Ad, Drainage Area to Structure (Post-Developed)260,130 (sq. ft.) 5.97 (ac.)
Drainage Area to Structure 5.97 (ac.)
Area of disturbance for structure 4.80 (ac.)
Q10, Peak Flow = Ci A 19.99 (cfs)
Skimmer Basin Design #1
Bottom of Basin Elevation =694.00
Depth of Basin (to storage)4.00 (ft.)
Storage Depth Elev. = 698.00
Emergency Spillway Elev. = 698.50
Top of Dam Elevation = 699.50 Diff. b/t spillway and top dam = 1.5 feet
Contour Area Area Volume Total
Elev. (sq. ft.) (ac. ft.) (cu. ft.) (cu. ft.)
694.00 2,732 0.063
695.00 4,008 0.092 3,370 3,370
696.00 5,523 0.127 4,766 8,136
697.00 7,377 0.169 6,450 14,586
698.00 9,327 0.214 8,352 22,938
698.50 10,325 0.237 19,810 27,946
699.00 13,444 0.309 5,942 33,888
700.00 14,919 0.342 14,182 48,069
Volume Calculation
Basin Volume Required (1800cu.ft./dist. ac) =8,647 (cu. ft.)
Basin Volume Provided at Spillway =22,938 (cu. ft.)Greater than required, therefore OK
Required Basin Surface Area (Q10x325 sq.ft.) = 6,498 (sq. ft.)
AS, Surface Area Provided =9,327 (sq. ft.)Greater than required, therefore OK
See following sheet for Skimmer Size Calculation from Fairclothskimmer.com
Emergency Spillway Calculation:Q=CLH^1.5
C= 2.8
Q10=19.99 (cfs)
Spillway Width =36.0 (ft.) 36'=4 SIDED OUTLET BOX W/ 4' WEIRS EACH SIDE + 20' EMERGENCY SPILLWAY
h= 0.34 (ft.)<0.5', Therefore OK
The ISAACS GROUP Date 9/18/2017
Weddington Glen Subdivision Weddington, North Carolina
Skimmer Basin Design & Calculations (BASIN #2)
Time of Concentration Calculation
Peak Flow Calculation
Total Time of Concentration, Tc 5.00 (min.)
i , 10 yr. Rainfall Intensity (table 2.3)7.44 (in./hr.)
C, Rainfall Runoff Coefficient 0.45
AD, Drainage Area to Structure (Pre-Developed)225,355 (sq. ft.) 5.17 (ac.)
Ad, Drainage Area to Structure (Post-Developed)222,048 (sq. ft.) 5.10 (ac.)
Drainage Area to Structure 5.17 (ac.)
Area of disturbance for structure 2.29 (ac.)
Q10, Peak Flow = Ci A 17.321 (cfs)
Skimmer Basin Design #2
Bottom of Basin Elevation =703.00
Depth of Basin (to storage)2.00 (ft.)
Storage Depth Elev.= 705.00
Emergency Spillway Elev. = 705.00
Top of Dam Elevation = 706.50 Diff. b/t spillway and top dam = 1.5 feet
Contour Area Area Volume Total
Elev. (sq. ft.) (ac. ft.) (cu. ft.) (cu. ft.)
703.00 1,653 0.038
704.00 3,548 0.081 2,601 2,601
705.00 5,658 0.130 4,603 7,204
705.50 6,019 0.138 2,919 10,123
706.00 6,498 0.149 3,129 13,252
707.00 6,998 0.161 6,748 20,000
Basin Volume Required (1800cu.ft./dist. ac) = 4,126 (cu. ft.)
Basin Volume Provided at Spillway =7,204 (cu. ft.)Greater than required, therefore OK
Required Basin Surface Area (Q10x325 sq.ft.) = 5,629 (sq. ft.)
AS, Surface Area Provided =5,658 (sq. ft.)Greater than required, therefore OK
See following sheet for Skimmer Size Calculation from Fairclothskimmer.com
Emergency Spillway Calculation:Q=CLH^1.5
C= 2.8
Q10=17.321 (cfs)
Spillway Width =20.0 (ft.)
h= 0.46 (ft.)<0.5', Therefore OK
Volume Calculation
The ISAACS GROUP Date 9/18/2017
Weddington Glen Subdivision Weddington, North Carolina
Skimmer Basin Design & Calculations (BASIN #3)
Time of Concentration Calculation
Peak Flow Calculation
Total Time of Concentration, Tc 5.00 (min.)
i , 10 yr. Rainfall Intensity (table 2.3)7.44 (in./hr.)
C, Rainfall Runoff Coefficient 0.45
AD, Drainage Area to Structure (Pre-Developed)319,609 (sq. ft.) 7.34 (ac.)
Ad, Drainage Area to Structure (Post-Developed)0 (sq. ft.) 0.00 (ac.)
Drainage Area to Structure 7.34 (ac.)
Area of disturbance for structure 3.84 (ac.)
Q10, Peak Flow = Ci A 24.565 (cfs)
Skimmer Basin Design #3
Bottom of Basin Elevation =702.50
Depth of Basin (to storage)2.50 (ft.)
Storage Depth Elev 705.00
Emergency Spillway Elev. = 705.00
Top of Dam Elevation = 706.50
Contour Area Area Volume Total
Elev. (sq. ft.) (ac. ft.) (cu. ft.) (cu. ft.)
702.50 2,697 0.062
703.00 3,806 0.087 1,626 1,626
704.00 5,665 0.130 6,272 6,272
705.00 10,157 0.233 13,963 15,589
705.50 12,769 0.293 5,732 21,320
707.00 15,471 0.355 21,180 42,500
Basin Volume Required (1800cu.ft./dist. ac) =6,915 (cu. ft.)
Basin Volume Provided at Spillway =15,589 (cu. ft.)Greater than required, therefore OK
Required Basin Surface Area (Q10x325 sq.ft.) = 7,984 (sq. ft.)
AS, Surface Area Provided =10,157 (sq. ft.)Greater than required, therefore OK
See following sheet for Skimmer Size Calculation from Fairclothskimmer.com
Emergency Spillway Calculation:Q=CLH^1.5
C= 2.8
Q10=24.565 (cfs)
Spillway Width =25.0 (ft.)
h= 0.50 (ft.)<0.5', Therefore OK
Volume Calculation
The ISAACS GROUP Date 9/17/2017
Weddington Glen Subdivision Weddington, North Carolina
Skimmer Basin Design & Calculations (BASIN #4)
Time of Concentration Calculation
Peak Flow Calculation
Total Time of Concentration, Tc 5.00 (min.)
i , 10 yr. Rainfall Intensity (table 2.3)7.44 (in./hr.)
C, Rainfall Runoff Coefficient 0.45
AD, Drainage Area to Structure (Pre-Developed)193,232 (sq. ft.) 4.44 (ac.)
Ad, Drainage Area to Structure (Post-Developed)0 (sq. ft.) 0.00 (ac.)
Drainage Area to Structure 4.44 (ac.)
Area of disturbance for structure 2.60 (ac.)
Q10, Peak Flow = Ci A 14.852 (cfs)
Skimmer Basin Design #4
Bottom of Basin Elevation =701.00
Depth of Basin (to spillway)2.50 (ft.)
Emergency Spillway Elev. = 703.50
Top of Dam Elevation = 705.00 Diff. b/t spillway and top dam = 1.5 feet
Contour Area Area Volume Total
Elev. (sq. ft.) (ac. ft.) (cu. ft.) (cu. ft.)
701.00 448 0.010
702.00 2,667 0.061 1,558 1,558
703.00 4,841 0.111 3,754 5,312
703.50 5,102 0.117 2,486 7,797
704.00 5,421 0.124 2,631 10,428
705.00 5,833 0.134 5,627 16,055
Basin Volume Required (1800cu.ft./dist. ac) =4,678 (cu. ft.)
Basin Volume Provided at Spillway =5,312 (cu. ft.)Greater than required, therefore OK
Required Basin Surface Area (Q10x325 sq.ft.) = 4,827 (sq. ft.)
AS, Surface Area Provided =4,841 (sq. ft.)Greater than required, therefore OK
See following sheet for Skimmer Size Calculation from Fairclothskimmer.com
Emergency Spillway Calculation:Q=CLH^1.5
C= 2.8
Q10=14.852 (cfs)
Spillway Width =16.0 (ft.)
h= 0.48 (ft.)<0.5', Therefore OK
Volume Calculation
The ISAACS GROUP Date 9/16/2017
Weddington Glen Subdivision Weddington, North Carolina
Riser Basin Design & Calculations (BASIN #5)
Peak Flow Calculation
Total Time of Concentration, Tc 5.00 (min.)
i , 10 yr. Rainfall Intensity (table 3-3)7.44 (in./hr.)
C, Rainfall Runoff Coefficient 0.45
AD, Drainage Area to Structure (Pre-Developed)236,646 (sq. ft.) 5.43 ac
Ad, Drainage Area to Structure (Post-Developed)701,049 (sq. ft.) 16.09 ac
Drainage Area to Structure 16.09 (ac.)
Area of disturbance for structure 7.25 (ac.) (INCLUDES HOMEBUILDER PHASE)
Q10, Peak Flow = Ci A 53.88 (cfs)
Bottom of Basin Elevation =684.00
Depth of Basin (to top riser)8.50 (ft.)
Riser Spillway Elevation =692.50 Diff. b/t Riser and Emer. Spillway=0.00
Emergency Spillway Elev. =692.50
Top of Dam Elevation =694.00
Contour Area Area Volume Total
Elev. (sq. ft.) (ac. ft.) (cu. ft.) (cu. ft.)
684.00 12,897 0.296
685.00 14,635 0.336 13,766 13,766
686.00 16,450 0.378 15,543 29,309
687.00 18,340 0.421 17,395 46,704
688.00 20,305 0.466 19,323 66,026
689.00 22,345 0.513 21,325 87,351
689.50 25,270 0.580 11,904 99,255
690.00 29,281 0.672 25,813 113,164
691.00 32,252 0.740 30,767 143,931
691.50 33,888 0.778 16,535 160,465
692.00 35,523 0.815 17,353 177,818
692.50 37,317 0.857 18,210 196,028
694.00 43,025 0.988 60,257 256,285
Elevation of measured Storage and Surface Area =689.50
Basin Volume Required (1800cu.ft./dist. ac) =13,050 (cu. ft.)
Basin Volume Provided at Spillway =99,255 (cu. ft.)Greater than required, therefore OK
Required Basin Surface Area (Q10x435 sq.ft.) =23,439 (sq. ft.)
AS, Surface Area Provided =25,270 (sq. ft.)Greater than required, therefore OK
See Next page for Principal Spillway Riser Barrel Design
Volume Calculation

Principal Spillway Riser Barrel Design:
i , 2 yr. Rainfall Intensity (table 3-3)5.42 (in./hr.)
Q2, Peak Flow = Ci A =39.25 (cfs)
Proposed Barrel Dia. =42 (in.)
Proposed Barrel Length (5.0' increments) =52.0 (ft.)
Proposed Riser width or diameter =60 (in.)
Analyze Weir, Orifice and Barrel flow for limiting (controling) flow in principal spillway
Weir flow Q=CLH^1.5 40.93 cfs
C=3.1 , H= Height b/t riser and emer. Spillway
L=total length of rectangular weir opening
Orifice flow Q=CA(2gH)^0.5 50.73 cfs
C=0.6
H=height b/t riser and emergency spillway
Pipe flow QP = (a√2gH)/√(1+Km+KpL) 115.82 cfs
Km=1
Kp=0.0341 from table 8.07a
H=depth from bottom basin to emergency spillway
Minimum principal spillway flow=40.93 Greater than Q2, therefore OK
Emergency Spillway Calculation:
Q10=53.88 (cfs)
QP=40.93 (cfs)
12.95 (cfs)
19.0 (ft.)
h= 0.37 (ft.)OK Principal outlet carrys the 10 year storm. 19' spillway provided
Concrete Anchor Buoyancy Calculation
Riser Height (h) =8.80 (ft.)(50-year max. W.S.E.L. depth)
Riser Outside Length (l) = 6.00 (ft.)
Riser Outside Width (w) = 6.00 (ft.)
Riser Wall Thickness (t) =0.50 (ft.)
Vol. of riser (VR) =316.8 (ft3)V R = l x w x h
Wt. of H2O displaced (WR)=19768.3 (lbs)W R = 62.4 lbs/ft 3 x V R
Conc. pad thickness =30 (in.)
Conc. pad width/length =10 (ft.)
Vol. of conc. pad (VC) =250.00 (ft3)
Wt. of H2O displaced (WC) =15600 (lbs)W C = 62.4 lbs/ft 3 x V C
Tot. Wt. of H2O displaced (WD) =35368.3 (lbs)WD = WR + WC
Unit wt. of concrete =150 (lbs/ft3)
Wt. of conc. pad =37500 (lbs)
Riser Outside Area (Ao) =36 (ft2)
Riser Inside Area (Ai) =25 (ft2)
Wt. of Riser Structure =14520 (lbs)
Factor of safety = wt. Conc. Pad + wt. Riser Structure
wt. of H2O displaced
F.S.= 1.47 OK
See following sheet for Skimmer Size Calculation from Fairclothskimmer.com
Qe = Q10-QP =
Spillway Width =
Faircloth Skimmer Sizing Calculation 
Basin No. 1 
Volume required = 8,647 cf 
Volume provided = 27,946 cf 
1. Size skimmer using a 2 day drawdown based on required volume 

2. Check Skimmer size with a 5 day drawdown per provided volume 

Use 2.5” skimmer with 2.1” orifice. 
Basin No. 2  
Volume required = 4,126 cf 
Volume provided = 7,204 cf 
1. Size skimmer using a 2 day drawdown based on required volume 

2. Check Skimmer size with a 5 day drawdown per provided volume 

Use 2.0” skimmer with 1.5” orifice. 

Basin No. 3 
Volume required = 6,915 cf 
Volume provided = 15,589 cf 
1. Size skimmer using a 2 day drawdown based on required volume 

2. Check Skimmer size with a 5 day drawdown per provided volume 

Use 2.0” skimmer with 1.9” orifice. 

Basin No. 4 
Volume required = 4,678 cf 
Volume provided = 5,312 cf 
1. Size skimmer using a 2 day drawdown based on required volume 

2. Check Skimmer size with a 5 day drawdown per provided volume 

Use 2.0” skimmer with 1.6” orifice. 

Basin No. 5 
Volume required = 13,050 cf 
Volume provided = 99,255 cf 
1. Size skimmer using a 2 day drawdown based on required volume 

2. Check Skimmer size with a 5 day drawdown per provided volume 

Use 3.0” skimmer with 2.5” orifice. 

WEDDINGTON GLEN SUBDIVISION

TOWN OF WEDDINGTON, NORTH CAROLINA

BMP DETENTION & WATER QUALITY CALCULATIONS

NO. BY DATE REVISION

Existing and Proposed Drainage Patterns & Points of Analysis

Drainage patterns to the two (2) proposed on-site BMP's are maintaining existing drainage patterns to the
maximum extent practicable as needed to create a balanced distribution of storm water flow thru BMP's 1
and 2 in a consistent manner with existing flows. Special consideration was given to the proposed locations
of BMP outfalls to minimize off-site impacts during various storm events due to existing off-site
infrastructure limitations.

As seen on the attached Pre-Developed Drainage Area map (Sheet C6.1 ) and Post-Developed Drainage
Area Map (Sheet C6.2), one analysis point was selected for evaluation of Pre and Post Developed
stormwater flows resulting from the development of the Weddington Glen Subdivision. Drainage area limits
shown are total drainage area to point of analysis to evaluate the net increase or decrease in stormwater
flows for the 1, 2, 10, 25, 50, and 100 year storm events for the contributing areas which encompass the
entire Weddington Glen Subdivision parcel. As seen below in the Results Summary, there is no net
increase in stormwater flow for all storm events up to and including the 100-year storm for the points of
analysis evaluated and are being conveyed thru stable channels without negative impacts to downstream
properties.

Hydrologic Precipitation Data used in the detention and water quality analysis for the 1, 2, 10, 25, 50 and
100 year storm events was taken from NOAA National Weather Service Hydrometeorological Design
Studies Center published data per the attached documents on the following pages.

Results Summary

DETENTION ANALYSIS SUMMARY TABLE
STORM EVENT
POINT OF ANALYSIS
PRE-DEV. FLOW POST-DEV FLOW

1-YR 24 HR. STORM 13.77 11.54

2-YR 24 HR. STORM 31.22 24.87

10-YR 24 HR. STORM 96.68 87.06

25-YR 24 HR. STORM 139.15 126.34
50-YR 24 HR. STORM 174.64 165.61
100-YR 24 HR. STORM 212.46 212.04
A-PRE DEV 1
A-PRE OUT
PRE-A1
A-PRE DEV 2
PRE-A2
B-POST DEV 4
B-POST OUT
B4(BYPASS)
B-POST DEV 3
B3(BYPASS)
B-POST DEV 2 BMP 2
POST-B2
BMP 2
B-POST DEV 1
BMP 1
POST-B1
BMP 1
Soil Map—Union County, North Carolina
(Weddington-Matthews Road Subdivision)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/20/2017
Page 1 of 3387600038761003876200387630038764003876500387660038767003876800387690038770003877100387720038773003877400387600038761003876200387630038764003876500387660038767003876800387690038770003877100387720038773003877400522700522800522900523000523100523200523300523400523500523600523700
522700 522800 522900 523000 523100 523200 523300 523400 523500 523600 523700
35° 2' 20'' N 80° 45' 6'' W35° 2' 20'' N80° 44' 22'' W35° 1' 33'' N
80° 45' 6'' W35° 1' 33'' N
80° 44' 22'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 300 600 1200 1800
Feet
0 100 200 400 600
Meters
Map Scale: 1:7,090 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 16, Sep 20, 2016
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Feb 11, 2011—Feb
13, 2011
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Soil Map—Union County, North Carolina
(Weddington-Matthews Road Subdivision)
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/20/2017
Page 2 of 3
Map Unit Legend
Union County, North Carolina (NC179)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
ApB Appling sandy loam, 2 to 8
percent slopes
20.0 9.1%
CeB2 Cecil gravelly sandy clay loam,
2 to 8 percent slopes,
moderately eroded
111.3 50.6%
CeC2 Cecil gravelly sandy clay loam,
8 to 15 percent slopes,
moderately eroded
8.8 4.0%
HeB Helena fine sandy loam, 2 to 8
percent slopes
79.8 36.3%
Totals for Area of Interest 220.0 100.0%
Soil Map—Union County, North Carolina Weddington-Matthews Road
Subdivision
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1/20/2017
Page 3 of 3
BMP CALCULATIONS
WEDDINGTON
Proposed BMP #1 (Sand Filter)
Sand Filter Designed per NCDEQ (Div. of Environmental Quality) and Town of Weddington Regulations
See Sheet C6.1 & C6.2 for Pre and Post-develop drainage area maps, Soil types, Tc flow path,
CN data and overall projet narrative.
Project Narrative:
Proposed BMP #1 (Sand Filter)
BMP #1 (Sand Filter) has been designed per the NCDEQ requirements of the contributing drainage area
(8.75 ac.) to meet 85% TSS removal, 25% TN and 40% TP removal targets. The SHWT was established as
required to establish the minimum vertical separations as outlined by the NCDEQ requirements. BMP #1 meets
or exceeds the following requirements:

• The control and treatment of the difference in the stormwater runoff from the pre-development and post-
development conditions for the one-year, 24-hour storm.
• Removal of an 85 percent average annual amount of Total Suspended Solids (85% TSS removal), 25%
TN (min) and 40% TP (min) removals
• Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours.
• Discharge the storage volume at a rate equal or less than the pre-development
discharge rate for the one-year, 24-hour storm
• Meet design of Stormwater Management Measures set forth in 15A NCAC 02H .1008.
• The post developed discharge rate at the property boundary is less than or equal to the pre development
rate for the (1,2,10,25,50 & 100) one, two, ten, twentyfive, fifty and one hundred year storm events.
Storm Event 1 Yr.-24 hr. 2 Yr.-24 hr. 10 Yr. - 24 hr. 25 Yr. - 24 hr. 50 Yr. - 24 hr. 100 Yr. - 24 hr.
(BMP #1-Sand Filter)
Post-Dev Flow 8.16 cfs 13.91 cfs 32.08 cfs 43.02 cfs 52.05 cfs 61.46 cfs
Routed Flow 0.21 cfs 0.85 cfs 24.85 cfs 40.35 cfs 50.72 cfs 60.98 cfs
Water Surface El 697 24 697 94 698 52 698 69 698 79 698 87
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-SAND FILTER BMP1-7000
BUA.xls
BMP Drainage Information:
Proposed BMP No.:1 (Sand Filter)
Proposed Drainage Area, A D (Ac.) =8.75 See Drainage Area Exhibit
Existing Impervious Area (BUA) (Ac.) =0.55
Proposed Impervious Area (BUA) (Ac.) =2.74
Proposed Percent Impervious Area, I A =31
Reference Post-Developed section of this report for Curve Numbers, Time of Concetration values, and Post-Developed Flows
for 1, 2, 10, 25, 50 and 100 year storm events to BMP #1.
Storm Event 1 Yr.-24 hr. 2 Yr.-24 hr. 10 Yr. - 24 hr. 25 Yr. - 24 hr. 50 Yr. - 24 hr. 100 Yr. - 24 hr.
(BMP #1-Sand Filter)
Post-Dev Flow 8.16 cfs 13.91 cfs 32.08 cfs 43.02 cfs 52.05 cfs 61.46 cfs
Routed Flow 0.21 cfs 0.85 cfs 24.85 cfs 40.35 cfs 50.72 cfs 60.98 cfs
Water Surface El.697.24 697.94 698.52 698.69 698.79 698.87
Freeboard Depth 2.76 2.06 1.48 1.31 1.21 1.13
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-SAND FILTER BMP1-7000
BUA.xls
Stage-Storage Information:
Top of Filter Media =694.00
Elevation
Surface Area
Including Forebay
(ft2)
Incremental Volume (ft3)
Cumulative
Volume Including
Forebay (ft3)
Forebay Surface
Area (ft2)
Forebay Cumulative Volume
(ft3)
694.00 1654 00695 0
695.00 2503 2,079 2,079 1537 1,116
696.00 3400 2,952 5,030 2503 3,136
697.00 7573 5,487 10,517
698.00 9553 8,563 19,080
698.50 10575.5 5,032 24,112
699.00 11598 5,543 29,655
699.50 12663.5 6,065 35,720
700.00 13729 6,598 42,319
Temporary Water Quality Storage Calculations:
(Simple Method)
Where: Rv=Runoff coefficient, I A=Impervious fraction (Imp. DA/Total DA), V=Volume,
RD=Design rainfall 2.78 (in), A=Watershed Area
Pre-Development: Rv=0.05+(0.9 x IA)0.106
Post-Development: Rv=0.05+(0.9 x IA)0.332
V=3,630 x RD x (Rv Post-Rv Pre) x A 19,876 (cu. ft)
Water Quality Volume (adjusted), WQv (ft3) 14,907 (cu. ft)
697.51
Compute Pretreatment System Requirements:
The sediment chamber storage area above the filter media must be sized to hold 20 percent of the water quality volume.
Required Sediment Forebay Volume (ft3) = 2981.383
Forebay Volume Provided @ WQ Storage Elevation (ft3) = 3136 21.04%of WQv
Interpolated from Storage TableTemporary Water Quality Storage Provided @ elev.:
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-SAND FILTER BMP1-7000
BUA.xls
Forebay Volume Provided @ WQ Storage Elevation (ft3) 3136 %of WQv
Sand Filter Bed Surface Area:
Depth of sand filter bed, d f (ft) = 1.5 = minimum depth of 1.5 ft (Per NCDENR Manual)
Coefficient of permeability for sand filter bed, k (ft/day) = 3.5 = 1.75 inch/hour
Time required to drain WQ v through sand filter, tf (day) =1.66 = 40 hours
Average head, hf (ft) =1.86 = WQ v Storage Depth
Required Surface Area for Sand Filter Bed, A f (ft2) =1,529.50 = (WQ v)(df)/(k)(tf)(hf + df) Darcy's Equation
Provided Surface Area for Sand Filter Bed, A f (ft2) =1,654.00
Stage-Discharge for Sand Filter Media:
Af = (WQv)(df)/[(k)(tf)(hf + df)]Darcy's Equation
(WQv)/(tf) = Qo = (Af)(k)(hf + df)/(df)
Af = provided surface area of filter bed (ft 2)
df = filter bed depth (ft)
k = coefficient of permeability of filter media (ft/day)
hf = average height of water above filter bed (ft)
Elevation hf (ft)Qo (cf/day)Qo (cfs)10*Qo (cfs)
694.00 0.00 0 0.00 0.00
695.00 1.00 9,648 0.11 1.12
696.00 2.00 13,508 0.16 1.56
697.00 3.00 17,367 0.20 2.01
698.00 4.00 21,226 0.25 2.46
698.50 4.50 23,156 0.27 2.68
699.00 5.00 25,086 0.29 2.90
699.50 5.50 27,015 0.31 3.13
700.00 6.00 28,945 0.34 3.35
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-SAND FILTER BMP1-7000
BUA.xls
BMP CALCULATIONS
WEDDINGTON
PROPOSED BMP #2(WETPOND)
Wet Pond & EFS/LS Designed per NCDEQ (Div. of Environmental Quality) and Town of Weddington Regulations
See Sheet C6.1 & C6.2 for Pre and Post-develop drainage area maps, Soil types, Tc flow path,
CN data and overall projet narrative.
Project Narrative:
Proposed BMP #2 (Wet Pond)
BMP #2 (Wet Pond) has been designed per the NCDEQ requirements of the contributing drainage area
(16.488 ac.) to meet 85% TSS removal, 25% TN and 40% TP removal targets. The SHWT was established as
required to establish the minimum vertical separations as outlined by the NCDEQ requirements. BMP #2 meets
or exceeds the following requirements:

• The control and treatment of the difference in the stormwater runoff from the pre-development and post-
development conditions for the one-year, 24-hour storm.
• Removal of an 85 percent average annual amount of Total Suspended Solids (85% TSS removal), 25%
TN (min) and 40% TP (min) removals
• Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours.
• Discharge the storage volume at a rate equal or less than the pre-development
discharge rate for the one-year, 24-hour storm
• Meet design of Stormwater Management Measures set forth in 15A NCAC 02H .1008.
• The post developed discharge rate at the property boundary is less than or equal to the pre development
rate for the (1,2,10,25,50 & 100) one, two, ten, twentyfive, fifty and one hundred year storm events.
Storm Event 1 Yr.-24 hr. 2 Yr.-24 hr. 10 Yr. - 24 hr. 25 Yr. - 24 hr. 50 Yr. - 24 hr. 100 Yr. - 24 hr.
(BMP #2-Wetpond)
Post-Dev Flow 20.55 cfs 32.49 cfs 69.21 cfs 91.18 cfs 108.63cfs 126.65 cfs
Routed Flow 115cfs 229cfs 11 82 cfs 23 49 cfs 43 78 cfs 67 81 cfs
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-WETPOND BMP2-7000 BUA.xls
Pond Drainage Information:
Proposed BMP No.:2 (Wet Pond)
Proposed Drainage Area (Ac.) =16.49 See Drainage Area Exhibit
Existing Impervious Area (BUA) (Ac.) =0.24
Proposed Impervious Area (BUA) (Ac.) =5.04
Proposed Percent Impervious Area =30.5
Reference Post-Developed section of this report for Curve Numbers, Time of Concetration values, and Post-Developed Flows
for 1, 2, 10, 25, 50 and 100 year storm events to BMP #2.
Storm Event 1 Yr.-24 hr. 2 Yr.-24 hr. 10 Yr. - 24 hr. 25 Yr. - 24 hr. 50 Yr. - 24 hr. 100 Yr. - 24 hr.
(BMP #2-Wetpond)
Post-Dev Flow 20.55 cfs 32.49 cfs 69.21 cfs 91.18 cfs 108.63cfs 126.65 cfs
Routed Flow 1.15 cfs 2.29 cfs 11.82 cfs 23.49 cfs 43.78 cfs 67.81 cfs
Water Surface El.690.36 690.82 691.96 692.59 692.94 693.21
Freeboard Depth 3.85 3.39 2.25 1.62 1.27 1.00
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-WETPOND BMP2-7000 BUA.xls
Pond Stage-Storage Information:
Perm. Water surface elevation =689.5
Elevation
Total Surface Area
Including Forebays
(s.f.)
Cummulative Det'n
Volume (cu.ft.)
Cummulative
Wet Volume
Including
Forebays
(cu.ft.)
Forebay
Surface Area
(s.f.)
Forebay
Cumulative
Volume (cu.
ft.)
Percentage of
total Volume
(20% desired)
684 12606 0 0 1900 0
685 14305 0 13,456 2416 2,158
686 16081 0 28,649 2983 4,858
687 17932 0 45,655 3600 8,149
688 19859 0 64,551 4268 12,083
689 21861 0 85,411 4986 16,710
689.5 25016 0 97,130 5364 19,298 19.87
690 29281 13,574 110,704 0 0
691 32252 44,341 141,471 0 0
692 35523 78,228 175,358 0 0
692.5 37317.5 96,438 193,568 0 0
693 39112 115,546 212,676 0 0
694 43025 156,695 253,825 0 0
Permanent Pool Calculations:
Permanent Pool Elevation =689.5 See Plan
Permanent Pool Average Depth =3.85
0.88
Per NCDEQ average depth
equation 3
SA/DA ratio for 85% Pollutant Removal Efficiency =
Interpolated From C-3 Wetpond Table 1 in NCDEQ
BMP Manual
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-WETPOND BMP2-7000 BUA.xls
6,353 =((SA/DA)/100) (Ac.)(43560)
Surface Area Provided (s.f.) @ 689.50 25,016 OK
Temporary Water Quality Storage Calculations:
(Simple Method)
Where: Rv=Runoff coefficient, IA=Impervious fraction (Imp. DA/Total DA), V=Volume,
RD=Design rainfall 2.78 (in), A=Watershed Area
Pre-Development: Rv=0.05+(0.9 x IA)0.063
Post-Development: Rv=0.05+(0.9 x IA)0.325
V=3,630 x RD x (Rv Post-Rv Pre) x A 43,549 (cu. ft)
Water Quality Volume (adjusted), WQv (ft3) 32,662 (cu. ft)
690.61
Temporary Water Quality De-watering Time Summary:
See Pond Pak calculation dewatering time for the 1 yr.-24 hr storm.
Using a 8" orifice, the time to drain the water at peak elevation of 690.36 is around 58 hrs.
Therefore 8" orifice is sufficient.
Water Quality Storage Provided @ elev.:Interpolated from Storage Table
Required Surface Area of Wet Pond (s.f.) =
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev 16157\Engineering\Calculations\BMP\7000 BUA\16157-WETPOND BMP2-7000 BUA.xls
CONCRETE ANCHOR ANTI-FLOTATION CALCULATION:
BMP #1 (sand filter)
Height of riser =7.9 ft
Cross Sectional Area of Riser =25.0 sf 4'x4' box w/ 6" wall thickness = 5'x5' box
Vol. of riser = 197 cf
Wt. of H 2O displaced =12,262 lbs
Conc. pad thickness =24 in
Conc. pad width/length =10 ft
Vol. of conc. pad = 200 cf
Wt. of H 2O displaced =12,480 lbs
Total Wt. of H 2O displaced =24,742
Unit wt. of concrete (pcf) = 150
Wt. of conc. pad (lb.) = 30,000
Vol. of conc. box (cf.) = 70 ((25-16)*(7.86)+(0.5*4*4))-((16*0.67)+(3.1416*3*3)/4)0*0.50
Wt. of conc. box (lb.) = 10,477
Total Wt. of conc. (lb.) = 40,477
Factor of safety = wt. Conc. Pad + Conc. Box
wt. Of H2O displaced
F.S.= 1.64
CONCRETE ANCHOR ANTI-FLOTATION CALCULATION:
BMP #2 (WET POND)
Height of riser =8.8 ft
Cross Sectional Area of Riser =36.0 sf 5,x5' box w/ 6" wall thickness = 6'x6' box
Vol. of riser = 316 cf
Wt. of H 2O displaced =19,701 lbs
Conc. pad thickness =30 in
Conc. pad width/length =10 ft
Vol. of conc. pad = 250 cf
Wt. of H 2O displaced =15,600 lbs
Total Wt. of H 2O displaced =35,301
Unit wt. of concrete (pcf) = 150
Wt. of conc. pad (lb.) = 37,500
Vol. of conc. box (cf.) = 98 ((36-25)*(8.7)+(0.67*4*4))-((16*0.67)+(3.1416*3.5*3.5)/4)0*0.50
Wt. of conc. box (lb.) = 14,704
Total Wt. of conc. (lb.) = 52,204
Factor of safety = wt. Conc. Pad + Conc. Box
wt. Of H2O displaced
F.S.= 1.48
Headwater Depth for Concrete BMP Outlet Culverts
  Refer to Water Quality Plan sheets C6.1 & C6.2 for BMP outlet structure summary.
BMP #1 ‐ Outlet Structure OS1
Culvert Dia. (in) =36
US Invert Elev. (ft) =691.31
DS Invert Elev. (ft) =691.04
Pipe Length. (ft) = 53.00
Q (cfs) =23.32 (see pondpack routing )
Head Water Depth for Concrete Pipe Culverts with inlet Control
* Hw/D calculated from Figure 5‐1 of the Charlotte Storm Water Design Manual
Entrance Type Hw/D Hw Hw Elev.
Q1)0.79 2.37 693.68 Hw Elev. Is below primary outlet orifices and weirs :. OK
Head for Concrete Pipe Culverts Flowing Full n=0.012
* H calculated from Figure 5‐2 of the Charlotte Storm Water Design Manual
ke H hO Hw Elev.
Q 0.5 0.4 3 694.71 Hw Elev. Is below primary outlet orifices and weirs :. OK
Manning's Equation full flow capacity check:
36" RCP @ 0.50% carries 51.09 cfs > Q=23.10 cfs, therefore OK
Q= 23.32 cfs
Capacity of 36 " RCP @ 0.50% = 51.09 cfs > 23.32 cfs
BMP #2 ‐ Outlet Structure OS2
Culvert Dia. (in) =42
US Invert Elev. (ft) =683.90
DS Invert Elev. (ft) =683.74
Pipe Length. (ft) = 52.00
Q (cfs) =18.98
Head Water Depth for Concrete Pipe Culverts with inlet Control
* Hw/D calculated from Figure 5‐1 of the Charlotte Storm Water Design Manual
Entrance Type Hw/D Hw Hw Elev.
Q1)0.57 2.00 685.90 Hw Elev. Is below primary outlet orifices and weirs :. OK
Head for Concrete Pipe Culverts Flowing Full n=0.012
* H calculated from Figure 5‐2 of the Charlotte Storm Water Design Manual
ke H hO Hw Elev.
Q 0.5 0.86 3.5 688.26 Hw Elev. Is below primary outlet orifices and weirs :. OK
Manning's Equation full flow capacity check:
42" RCP @ 0.30% carries 59.70 cfs > 18.98 cfs, therefore OK
Q=18.98 cfs
Capacity of 42 " RCP @ 0.30% = 59.70 cfs > 18.98 cfs
P:\Active Projects\Hopper Communities\Weddington Matthews Rd Dev  16157\Engineering\Calculations\BMP\16157‐BMP Outlet Culvert.xlsx

Job File: W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Rain Dir: W:\PONDPAK\RAINFALL\
==========================
JOB TITLE
==========================
WEDDINGTON ROAD SUBDIVISION
UNION COUNTY, NORTH CAROLINA
OVERALL DETENTION ANALYSIS

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Table of Contents i
Table of Contents
********************** MASTER SUMMARY **********************

Watershed....... Master Network Summary ............. 1.01
********************** TC CALCULATIONS *********************

A-PRE DEV 1..... Tc Calcs ........................... 2.01

A-PRE DEV 2..... Tc Calcs ........................... 2.05

B-POST DEV 3.... Tc Calcs ........................... 2.08

B-POST DEV 4.... Tc Calcs ........................... 2.12
********************** CN CALCULATIONS *********************

A-PRE DEV 1..... Runoff CN-Area ..................... 3.01

A-PRE DEV 2..... Runoff CN-Area ..................... 3.02

B-POST DEV 1.... Runoff CN-Area ..................... 3.03

B-POST DEV 2.... Runoff CN-Area ..................... 3.04

B-POST DEV 3.... Runoff CN-Area ..................... 3.05

B-POST DEV 4.... Runoff CN-Area ..................... 3.06
*********************** TIME VS.ELEV ***********************

BMP 2 OUT 1
Time-Elev .......................... 4.01
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Table of Contents ii
Table of Contents (continued)
*********************** POND VOLUMES ***********************

BMP 1........... Vol: Elev-Volume ................... 5.01

BMP 2........... Vol: Elev-Volume ................... 5.02
******************** OUTLET STRUCTURES *********************

BMP 1........... Outlet Input Data .................. 6.01
Individual Outlet Curves ........... 6.04
Composite Rating Curve ............. 6.07

BMP 2........... Outlet Input Data .................. 6.08
Individual Outlet Curves ........... 6.11
Composite Rating Curve ............. 6.15
*********************** POND ROUTING ***********************

BMP 1........... Pond E-V-Q Table ................... 7.01

BMP 2........... Pond E-V-Q Table ................... 7.03
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

MASTER DESIGN STORM SUMMARY

Default Network Design Storm File, ID STORMS.RNQ Weddington 24

Total
Depth Rainfall
Return Event in Type RNF File RNF ID
------------ ------ ---------------- -------- ----------------
1 2.5800 Synthetic Curve DETENT SCS TP II-6 MIN
2 3.2500 Synthetic Curve DETENT SCS Type II
10 5.0900 Synthetic Curve DETENT SCS Type II
25 6.1000 Synthetic Curve DETENT SCS Type II
50 6.8900 Synthetic Curve DETENT SCS Type II
100 7.7000 Synthetic Curve DETENT SCS Type II

MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)

Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond
Storage
Node ID Type Event ac-ft Trun hrs cfs ft ac-
ft
----------------- ---- ------ ---------- -- --------- -------- -------- --------
----
A-PRE DEV 1 AREA 1 1.982 12.4500 10.83
A-PRE DEV 1 AREA 2 3.625 12.3500 23.96
A-PRE DEV 1 AREA 10 9.481 12.3500 73.46
A-PRE DEV 1 AREA 25 13.239 12.3500 105.01
A-PRE DEV 1 AREA 50 16.357 12.3500 130.99
A-PRE DEV 1 AREA 100 19.681 12.3500 158.48

A-PRE DEV 2 AREA 1 .539 12.3000 3.13
A-PRE DEV 2 AREA 2 1.026 12.2500 7.60
A-PRE DEV 2 AREA 10 2.815 12.2000 25.34
A-PRE DEV 2 AREA 25 3.982 12.2000 37.13
A-PRE DEV 2 AREA 50 4.957 12.2000 46.92
A-PRE DEV 2 AREA 100 6.000 12.2000 57.34

*A-PRE OUT JCT 1 2.521 12.3500 13.77
*A-PRE OUT JCT 2 4.651 12.3500 31.22
*A-PRE OUT JCT 10 12.295 12.3000 96.68
*A-PRE OUT JCT 25 17.221 12.3000 139.15
*A-PRE OUT JCT 50 21.314 12.2500 174.64
*A-PRE OUT JCT 100 25.681 12.2500 212.46

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Master Network Summary Page 1.02
Name.... Watershed
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method

(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)

Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond
Storage
Node ID Type Event ac-ft Trun hrs cfs ft ac-
ft
----------------- ---- ------ ---------- -- --------- -------- -------- --------
----
B-POST DEV 1 AREA 1 .477 11.9500 8.16
B-POST DEV 1 AREA 2 .780 11.9500 13.91
B-POST DEV 1 AREA 10 1.776 11.9500 32.08
B-POST DEV 1 AREA 25 2.383 11.9000 43.02
B-POST DEV 1 AREA 50 2.877 11.9000 52.05
B-POST DEV 1 AREA 100 3.396 11.9000 61.46

B-POST DEV 2 AREA 1 1.154 11.9500 20.55
B-POST DEV 2 AREA 2 1.800 11.9500 32.49
B-POST DEV 2 AREA 10 3.831 11.9000 69.21
B-POST DEV 2 AREA 25 5.038 11.9000 91.18
B-POST DEV 2 AREA 50 6.011 11.9000 108.63
B-POST DEV 2 AREA 100 7.027 11.9000 126.65

B-POST DEV 3 AREA 1 1.476 12.4000 8.54
B-POST DEV 3 AREA 2 2.650 12.3500 18.08
B-POST DEV 3 AREA 10 6.779 12.3000 53.30
B-POST DEV 3 AREA 25 9.408 12.3000 75.78
B-POST DEV 3 AREA 50 11.582 12.3000 94.26
B-POST DEV 3 AREA 100 13.895 12.3000 113.80

B-POST DEV 4 AREA 1 .338 12.3000 1.89
B-POST DEV 4 AREA 2 .659 12.2500 4.85
B-POST DEV 4 AREA 10 1.855 12.2500 16.86
B-POST DEV 4 AREA 25 2.642 12.2000 24.83
B-POST DEV 4 AREA 50 3.301 12.2000 31.54
B-POST DEV 4 AREA 100 4.009 12.2000 38.69

*B-POST OUT JCT 1 3.442 12.4000 11.54
*B-POST OUT JCT 2 5.886 12.3500 24.87
*B-POST OUT JCT 10 14.237 12.2500 87.06
*B-POST OUT JCT 25 19.468 12.2000 126.34
*B-POST OUT JCT 50 23.769 12.1000 165.61
*B-POST OUT JCT 100 28.324 12.0500 212.04

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Master Network Summary Page 1.03
Name.... Watershed
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method

(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)

Max
Return HYG Vol Qpeak Qpeak Max WSEL Pond
Storage
Node ID Type Event ac-ft Trun hrs cfs ft ac-
ft
----------------- ---- ------ ---------- -- --------- -------- -------- --------
----
BMP 1 IN POND 1 .477 11.9500 8.16
BMP 1 IN POND 2 .780 11.9500 13.91
BMP 1 IN POND 10 1.776 11.9500 32.08
BMP 1 IN POND 25 2.383 11.9000 43.02
BMP 1 IN POND 50 2.877 11.9000 52.05
BMP 1 IN POND 100 3.396 11.9000 61.46

BMP 1 OUT POND 1 .475 15.6000 .21 697.24
.289
BMP 1 OUT POND 2 .779 13.3500 .85 697.94
.426
BMP 1 OUT POND 10 1.775 12.0000 24.85 698.52
.559
BMP 1 OUT POND 25 2.382 12.0000 40.35 698.69
.602
BMP 1 OUT POND 50 2.876 11.9500 50.72 698.79
.627
BMP 1 OUT POND 100 3.395 11.9500 60.98 698.87
.648

BMP 2 IN POND 1 1.154 11.9500 20.55
BMP 2 IN POND 2 1.800 11.9500 32.49
BMP 2 IN POND 10 3.831 11.9000 69.21
BMP 2 IN POND 25 5.038 11.9000 91.18
BMP 2 IN POND 50 6.011 11.9000 108.63
BMP 2 IN POND 100 7.027 11.9000 126.65

BMP 2 OUT POND 1 1.153 13.4500 1.15 690.36
.567
BMP 2 OUT POND 2 1.798 12.9000 2.29 690.82
.891
BMP 2 OUT POND 10 3.829 12.2000 11.82 691.96
1.767
BMP 2 OUT POND 25 5.037 12.1000 23.49 692.59
2.286
BMP 2 OUT POND 50 6.009 12.1000 43.78 692.94
2.571
BMP 2 OUT POND 100 7.025 12.0500 67.81 693.21
2.829

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.01
Name.... A-PRE DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
TIME OF CONCENTRATION CALCULATOR
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

------------------------------------------------------------------------
Segment #1: Tc: TR-55 Channel
Flow Area 21.0000 sq.ft
Wetted Perimeter 12.40 ft
Hydraulic Radius 1.69 ft
Slope .016900 ft/ft
Mannings n .0350
Hydraulic Length 956.00 ft
Avg.Velocity 7.86 ft/sec
Segment #1 Time: .0338 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Channel
Flow Area 6.3790 sq.ft
Wetted Perimeter 9.83 ft
Hydraulic Radius .65 ft
Slope .024200 ft/ft
Mannings n .0350
Hydraulic Length 1046.00 ft
Avg.Velocity 4.96 ft/sec
Segment #2 Time: .0585 hrs
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Shallow
Hydraulic Length 1183.00 ft
Slope .013000 ft/ft
Unpaved
Avg.Velocity 1.84 ft/sec
Segment #3 Time: .1786 hrs
------------------------------------------------------------------------
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.02
Name.... A-PRE DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Segment #4: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 150.00 ft
2yr, 24hr P 3.2500 in
Slope .010000 ft/ft
Avg.Velocity .10 ft/sec
Segment #4 Time: .4307 hrs
------------------------------------------------------------------------
=========================
Total Tc: .7017 hrs
=========================
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.03
Name.... A-PRE DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------

==== SCS TR-55 Sheet Flow ==============================================

Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))

Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, %

==== SCS TR-55 Shallow Concentrated Flow ===============================

Unpaved surface:
V = 16.1345 * (Sf**0.5)

Paved surface:
V = 20.3282 * (Sf**0.5)

Tc = (Lf / V) / (3600sec/hr)

Where: V = Velocity, ft/sec
Sf = Slope, ft/ft
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.04
Name.... A-PRE DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

==== SCS Channel Flow ==================================================

R = Aq / Wp
V = (1.49 * (R**(2/3)) * (Sf**-0.5)) / n

Tc = (Lf / V) / (3600sec/hr)

Where: R = Hydraulic radius
Aq = Flow area, sq.ft.
Wp = Wetted perimeter, ft
V = Velocity, ft/sec
Sf = Slope, ft/ft
n = Mannings n
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.05
Name.... A-PRE DEV 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
TIME OF CONCENTRATION CALCULATOR
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

------------------------------------------------------------------------
Segment #1: Tc: TR-55 Channel
Flow Area 112.5000 sq.ft
Wetted Perimeter 75.24 ft
Hydraulic Radius 1.50 ft
Slope .030000 ft/ft
Mannings n .0350
Hydraulic Length 1257.00 ft
Avg.Velocity 9.64 ft/sec
Segment #1 Time: .0362 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Shallow
Hydraulic Length 1119.00 ft
Slope .019300 ft/ft
Unpaved
Avg.Velocity 2.24 ft/sec
Segment #2 Time: .1387 hrs
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 150.00 ft
2yr, 24hr P 3.2500 in
Slope .015000 ft/ft
Avg.Velocity .11 ft/sec
Segment #3 Time: .3662 hrs
------------------------------------------------------------------------
=========================
Total Tc: .5411 hrs
=========================
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.06
Name.... A-PRE DEV 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------

==== SCS TR-55 Sheet Flow ==============================================

Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))

Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, %

==== SCS TR-55 Shallow Concentrated Flow ===============================

Unpaved surface:
V = 16.1345 * (Sf**0.5)

Paved surface:
V = 20.3282 * (Sf**0.5)

Tc = (Lf / V) / (3600sec/hr)

Where: V = Velocity, ft/sec
Sf = Slope, ft/ft
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.07
Name.... A-PRE DEV 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

==== SCS Channel Flow ==================================================

R = Aq / Wp
V = (1.49 * (R**(2/3)) * (Sf**-0.5)) / n

Tc = (Lf / V) / (3600sec/hr)

Where: R = Hydraulic radius
Aq = Flow area, sq.ft.
Wp = Wetted perimeter, ft
V = Velocity, ft/sec
Sf = Slope, ft/ft
n = Mannings n
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.08
Name.... B-POST DEV 3

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
TIME OF CONCENTRATION CALCULATOR
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

------------------------------------------------------------------------
Segment #1: Tc: TR-55 Channel
Flow Area 21.0000 sq.ft
Wetted Perimeter 12.40 ft
Hydraulic Radius 1.69 ft
Slope .016900 ft/ft
Mannings n .0350
Hydraulic Length 956.00 ft
Avg.Velocity 7.86 ft/sec
Segment #1 Time: .0338 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Channel
Flow Area 6.3790 sq.ft
Wetted Perimeter 9.83 ft
Hydraulic Radius .65 ft
Slope .024200 ft/ft
Mannings n .0350
Hydraulic Length 614.00 ft
Avg.Velocity 4.96 ft/sec
Segment #2 Time: .0344 hrs
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Channel
Flow Area 4.2100 sq.ft
Wetted Perimeter 5.54 ft
Hydraulic Radius .76 ft
Slope .010000 ft/ft
Mannings n .0120
Hydraulic Length 486.00 ft
Avg.Velocity 10.34 ft/sec
Segment #3 Time: .0131 hrs
------------------------------------------------------------------------
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.09
Name.... B-POST DEV 3

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Segment #4: Tc: TR-55 Shallow
Hydraulic Length 1197.00 ft
Slope .013000 ft/ft
Unpaved
Avg.Velocity 1.84 ft/sec
Segment #4 Time: .1807 hrs
------------------------------------------------------------------------
Segment #5: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 150.00 ft
2yr, 24hr P 3.2500 in
Slope .010000 ft/ft
Avg.Velocity .10 ft/sec
Segment #5 Time: .4307 hrs
------------------------------------------------------------------------
=========================
Total Tc: .6927 hrs
=========================
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.10
Name.... B-POST DEV 3

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------

==== SCS TR-55 Sheet Flow ==============================================

Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))

Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, %

==== SCS TR-55 Shallow Concentrated Flow ===============================

Unpaved surface:
V = 16.1345 * (Sf**0.5)

Paved surface:
V = 20.3282 * (Sf**0.5)

Tc = (Lf / V) / (3600sec/hr)

Where: V = Velocity, ft/sec
Sf = Slope, ft/ft
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.11
Name.... B-POST DEV 3

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

==== SCS Channel Flow ==================================================

R = Aq / Wp
V = (1.49 * (R**(2/3)) * (Sf**-0.5)) / n

Tc = (Lf / V) / (3600sec/hr)

Where: R = Hydraulic radius
Aq = Flow area, sq.ft.
Wp = Wetted perimeter, ft
V = Velocity, ft/sec
Sf = Slope, ft/ft
n = Mannings n
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.12
Name.... B-POST DEV 4

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
TIME OF CONCENTRATION CALCULATOR
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

------------------------------------------------------------------------
Segment #1: Tc: TR-55 Channel
Flow Area 112.5000 sq.ft
Wetted Perimeter 75.24 ft
Hydraulic Radius 1.50 ft
Slope .030000 ft/ft
Mannings n .0350
Hydraulic Length 1343.00 ft
Avg.Velocity 9.64 ft/sec
Segment #1 Time: .0387 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Channel
Flow Area 2.6900 sq.ft
Wetted Perimeter 4.43 ft
Hydraulic Radius .61 ft
Slope .007000 ft/ft
Mannings n .0120
Hydraulic Length 430.00 ft
Avg.Velocity 7.45 ft/sec
Segment #2 Time: .0160 hrs
------------------------------------------------------------------------
Segment #3: Tc: TR-55 Shallow
Hydraulic Length 835.00 ft
Slope .019300 ft/ft
Unpaved
Avg.Velocity 2.24 ft/sec
Segment #3 Time: .1035 hrs
------------------------------------------------------------------------
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.13
Name.... B-POST DEV 4

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Segment #4: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 150.00 ft
2yr, 24hr P 3.2500 in
Slope .015000 ft/ft
Avg.Velocity .11 ft/sec
Segment #4 Time: .3662 hrs
------------------------------------------------------------------------
=========================
Total Tc: .5244 hrs
=========================
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.14
Name.... B-POST DEV 4

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------

==== SCS TR-55 Sheet Flow ==============================================

Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))

Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, %

==== SCS TR-55 Shallow Concentrated Flow ===============================

Unpaved surface:
V = 16.1345 * (Sf**0.5)

Paved surface:
V = 20.3282 * (Sf**0.5)

Tc = (Lf / V) / (3600sec/hr)

Where: V = Velocity, ft/sec
Sf = Slope, ft/ft
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Tc Calcs Page 2.15
Name.... B-POST DEV 4

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW

==== SCS Channel Flow ==================================================

R = Aq / Wp
V = (1.49 * (R**(2/3)) * (Sf**-0.5)) / n

Tc = (Lf / V) / (3600sec/hr)

Where: R = Hydraulic radius
Aq = Flow area, sq.ft.
Wp = Wetted perimeter, ft
V = Velocity, ft/sec
Sf = Slope, ft/ft
n = Mannings n
Tc = Time of concentration, hrs
Lf = Flow length, ft

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.01
Name.... A-PRE DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Pasture/Open, Class B-Good 61 28.903 61.00
Wooded, Class B-Good 55 5.455 55.00
Impervious 98 5.256 98.00
Pasture/Open, Class C-Good 74 6.500 74.00
Wooded, Class C-Good 70 14.838 70.00
COMPOSITE AREA & WEIGHTED CN ---> 60.952 67.23 (67)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.02
Name.... A-PRE DEV 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Pasture/Open, Class B-Good 61 11.331 61.00
Wooded, Class B-Good 55 2.199 55.00
Impervious 98 .689 98.00
Pasture/Open, Class C-Good 74 2.261 74.00
Wooded, Class C-Good 70 3.230 70.00
COMPOSITE AREA & WEIGHTED CN ---> 19.710 64.59 (65)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.03
Name.... B-POST DEV 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Impervious (Road, SW & BUA) 98 2.740 98.00
Pasture/Open, Class B-Good 61 3.797 61.00
Wooded, Class v-Good 55 1.014 55.00
Pasture/Open, Class C-Good 74 1.199 74.00
COMPOSITE AREA & WEIGHTED CN ---> 8.750 73.67 (74)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.04
Name.... B-POST DEV 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Impervious (Road, SW & BUA) 98 5.035 98.00
Wetpond 98 .768 98.00
Pasture/Open, Class B-Good 61 4.766 61.00
Wooded, Class B-Good 55 .195 55.00
Open Space, Class B-Good 74 4.704 74.00
Wooded, Class B-Good 70 1.020 70.00
COMPOSITE AREA & WEIGHTED CN ---> 16.488 78.22 (78)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.05
Name.... B-POST DEV 3

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Exist. Impervious 98 4.766 98.00
Pasture/Open, Class B-Good 61 22.736 61.00
Wooded, Class B-Good 55 2.675 55.00
Pasture/Open, Class C-Good 74 2.078 74.00
Woodwd, Class C-Good 70 9.592 70.00
COMPOSITE AREA & WEIGHTED CN ---> 41.847 67.54 (68)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Runoff CN-Area Page 3.06
Name.... B-POST DEV 4

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Existing Impervious 98 .689 98.00
Pasture/Open, Class b-Good 61 8.021 61.00
Wooded, Class B-Good 55 1.863 55.00
Pasture/Open, ClassC-Good 74 .819 74.00
Wooded, Class C-Good 70 2.185 70.00
COMPOSITE AREA & WEIGHTED CN ---> 13.577 64.29 (64)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Time-Elev Page 4.01
Name.... BMP 2 OUT Tag: 1 Event: 1 yr
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Storm... SCS TP II-6 MIN Tag: 1
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
10.7500 | 689.50 689.50 689.50 689.50 689.50
11.0000 | 689.50 689.50 689.50 689.50 689.50
11.2500 | 689.50 689.51 689.51 689.51 689.51
11.5000 | 689.52 689.52 689.53 689.54 689.55
11.7500 | 689.58 689.62 689.69 689.79 689.92
12.0000 | 690.04 690.13 690.19 690.22 690.23
12.2500 | 690.25 690.26 690.28 690.29 690.30
12.5000 | 690.31 690.31 690.32 690.32 690.33
12.7500 | 690.33 690.34 690.34 690.34 690.35
13.0000 | 690.35 690.35 690.35 690.36 690.36
13.2500 | 690.36 690.36 690.36 690.36 690.36
13.5000 | 690.36 690.36 690.36 690.36 690.36
13.7500 | 690.36 690.36 690.36 690.36 690.36
14.0000 | 690.36 690.36 690.35 690.35 690.35
14.2500 | 690.35 690.35 690.35 690.35 690.34
14.5000 | 690.34 690.34 690.34 690.34 690.34
14.7500 | 690.34 690.33 690.33 690.33 690.33
15.0000 | 690.33 690.32 690.32 690.32 690.32
15.2500 | 690.32 690.32 690.31 690.31 690.31
15.5000 | 690.31 690.30 690.30 690.30 690.30
15.7500 | 690.30 690.29 690.29 690.29 690.29
16.0000 | 690.28 690.28 690.28 690.28 690.27
16.2500 | 690.27 690.27 690.27 690.26 690.26
16.5000 | 690.26 690.26 690.25 690.25 690.25
16.7500 | 690.25 690.25 690.24 690.24 690.24
17.0000 | 690.24 690.23 690.23 690.23 690.23
17.2500 | 690.22 690.22 690.22 690.22 690.21
17.5000 | 690.21 690.21 690.21 690.21 690.20
17.7500 | 690.20 690.20 690.20 690.19 690.19
18.0000 | 690.19 690.19 690.19 690.18 690.18
18.2500 | 690.18 690.18 690.17 690.17 690.17
18.5000 | 690.17 690.16 690.16 690.16 690.16
18.7500 | 690.16 690.15 690.15 690.15 690.15
19.0000 | 690.14 690.14 690.14 690.14 690.14
19.2500 | 690.13 690.13 690.13 690.13 690.12
19.5000 | 690.12 690.12 690.12 690.12 690.11
19.7500 | 690.11 690.11 690.11 690.10 690.10
20.0000 | 690.10 690.10 690.10 690.09 690.09
20.2500 | 690.09 690.09 690.09 690.08 690.08
20.5000 | 690.08 690.08 690.08 690.07 690.07
20.7500 | 690.07 690.07 690.07 690.06 690.06
21.0000 | 690.06 690.06 690.06 690.05 690.05
21.2500 | 690.05 690.05 690.05 690.04 690.04
21.5000 | 690.04 690.04 690.04 690.04 690.03
21.7500 | 690.03 690.03 690.03 690.03 690.03
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Time-Elev Page 4.02
Name.... BMP 2 OUT Tag: 1 Event: 1 yr
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Storm... SCS TP II-6 MIN Tag: 1
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
22.0000 | 690.02 690.02 690.02 690.02 690.02
22.2500 | 690.02 690.01 690.01 690.01 690.01
22.5000 | 690.01 690.01 690.01 690.00 690.00
22.7500 | 690.00 690.00 690.00 690.00 689.99
23.0000 | 689.99 689.99 689.99 689.99 689.99
23.2500 | 689.99 689.98 689.98 689.98 689.98
23.5000 | 689.98 689.98 689.97 689.97 689.97
23.7500 | 689.97 689.97 689.97 689.97 689.96
24.0000 | 689.96 689.96 689.96 689.95 689.95
24.2500 | 689.95 689.94 689.94 689.94 689.93
24.5000 | 689.93 689.93 689.92 689.92 689.92
24.7500 | 689.91 689.91 689.91 689.91 689.90
25.0000 | 689.90 689.90 689.89 689.89 689.89
25.2500 | 689.88 689.88 689.88 689.88 689.87
25.5000 | 689.87 689.87 689.86 689.86 689.86
25.7500 | 689.86 689.85 689.85 689.85 689.85
26.0000 | 689.84 689.84 689.84 689.83 689.83
26.2500 | 689.83 689.83 689.82 689.82 689.82
26.5000 | 689.82 689.81 689.81 689.81 689.81
26.7500 | 689.81 689.80 689.80 689.80 689.80
27.0000 | 689.79 689.79 689.79 689.79 689.79
27.2500 | 689.78 689.78 689.78 689.78 689.77
27.5000 | 689.77 689.77 689.77 689.77 689.76
27.7500 | 689.76 689.76 689.76 689.76 689.75
28.0000 | 689.75 689.75 689.75 689.75 689.74
28.2500 | 689.74 689.74 689.74 689.74 689.74
28.5000 | 689.73 689.73 689.73 689.73 689.73
28.7500 | 689.72 689.72 689.72 689.72 689.72
29.0000 | 689.72 689.71 689.71 689.71 689.71
29.2500 | 689.71 689.71 689.71 689.70 689.70
29.5000 | 689.70 689.70 689.70 689.70 689.69
29.7500 | 689.69 689.69 689.69 689.69 689.69
30.0000 | 689.69 689.68 689.68 689.68 689.68
30.2500 | 689.68 689.68 689.68 689.67 689.67
30.5000 | 689.67 689.67 689.67 689.67 689.67
30.7500 | 689.67 689.66 689.66 689.66 689.66
31.0000 | 689.66 689.66 689.66 689.66 689.65
31.2500 | 689.65 689.65 689.65 689.65 689.65
31.5000 | 689.65 689.65 689.65 689.64 689.64
31.7500 | 689.64 689.64 689.64 689.64 689.64
32.0000 | 689.64 689.64 689.63 689.63 689.63
32.2500 | 689.63 689.63 689.63 689.63 689.63
32.5000 | 689.63 689.63 689.62 689.62 689.62
32.7500 | 689.62 689.62 689.62 689.62 689.62
33.0000 | 689.62 689.62 689.62 689.61 689.61
33.2500 | 689.61 689.61 689.61 689.61 689.61
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Time-Elev Page 4.03
Name.... BMP 2 OUT Tag: 1 Event: 1 yr
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Storm... SCS TP II-6 MIN Tag: 1
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
33.5000 | 689.61 689.61 689.61 689.61 689.61
33.7500 | 689.60 689.60 689.60 689.60 689.60
34.0000 | 689.60 689.60 689.60 689.60 689.60
34.2500 | 689.60 689.60 689.60 689.59 689.59
34.5000 | 689.59 689.59 689.59 689.59 689.59
34.7500 | 689.59 689.59 689.59 689.59 689.59
35.0000 | 689.59 689.59 689.59 689.58 689.58
35.2500 | 689.58 689.58 689.58 689.58 689.58
35.5000 | 689.58 689.58 689.58 689.58 689.58
35.7500 | 689.58 689.58 689.58 689.58 689.57
36.0000 | 689.57 689.57 689.57 689.57 689.57
36.2500 | 689.57 689.57 689.57 689.57 689.57
36.5000 | 689.57 689.57 689.57 689.57 689.57
36.7500 | 689.57 689.57 689.57 689.56 689.56
37.0000 | 689.56 689.56 689.56 689.56 689.56
37.2500 | 689.56 689.56 689.56 689.56 689.56
37.5000 | 689.56 689.56 689.56 689.56 689.56
37.7500 | 689.56 689.56 689.56 689.56 689.56
38.0000 | 689.55 689.55 689.55 689.55 689.55
38.2500 | 689.55 689.55 689.55 689.55 689.55
38.5000 | 689.55 689.55 689.55 689.55 689.55
38.7500 | 689.55 689.55 689.55 689.55 689.55
39.0000 | 689.55 689.55 689.55 689.55 689.55
39.2500 | 689.55 689.54 689.54 689.54 689.54
39.5000 | 689.54 689.54 689.54 689.54 689.54
39.7500 | 689.54 689.54 689.54 689.54 689.54
40.0000 | 689.54 689.54 689.54 689.54 689.54
40.2500 | 689.54 689.54 689.54 689.54 689.54
40.5000 | 689.54 689.54 689.54 689.54 689.54
40.7500 | 689.54 689.54 689.54 689.54 689.53
41.0000 | 689.53 689.53 689.53 689.53 689.53
41.2500 | 689.53 689.53 689.53 689.53 689.53
41.5000 | 689.53 689.53 689.53 689.53 689.53
41.7500 | 689.53 689.53 689.53 689.53 689.53
42.0000 | 689.53 689.53 689.53 689.53 689.53
42.2500 | 689.53 689.53 689.53 689.53 689.53
42.5000 | 689.53 689.53 689.53 689.53 689.53
42.7500 | 689.53 689.53 689.53 689.53 689.53
43.0000 | 689.53 689.53 689.53 689.52 689.52
43.2500 | 689.52 689.52 689.52 689.52 689.52
43.5000 | 689.52 689.52 689.52 689.52 689.52
43.7500 | 689.52 689.52 689.52 689.52 689.52
44.0000 | 689.52 689.52 689.52 689.52 689.52
44.2500 | 689.52 689.52 689.52 689.52 689.52
44.5000 | 689.52 689.52 689.52 689.52 689.52
44.7500 | 689.52 689.52 689.52 689.52 689.52
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Time-Elev Page 4.04
Name.... BMP 2 OUT Tag: 1 Event: 1 yr
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Storm... SCS TP II-6 MIN Tag: 1
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
45.0000 | 689.52 689.52 689.52 689.52 689.52
45.2500 | 689.52 689.52 689.52 689.52 689.52
45.5000 | 689.52 689.52 689.52 689.52 689.52
45.7500 | 689.52 689.52 689.52 689.52 689.52
46.0000 | 689.52 689.52 689.52 689.52 689.52
46.2500 | 689.52 689.52 689.52 689.52 689.52
46.5000 | 689.51 689.51 689.51 689.51 689.51
46.7500 | 689.51 689.51 689.51 689.51 689.51
47.0000 | 689.51 689.51 689.51 689.51 689.51
47.2500 | 689.51 689.51 689.51 689.51 689.51
47.5000 | 689.51 689.51 689.51 689.51 689.51
47.7500 | 689.51 689.51 689.51 689.51 689.51
48.0000 | 689.51 689.51 689.51 689.51 689.51
48.2500 | 689.51 689.51 689.51 689.51 689.51
48.5000 | 689.51 689.51 689.51 689.51 689.51
48.7500 | 689.51 689.51 689.51 689.51 689.51
49.0000 | 689.51 689.51 689.51 689.51 689.51
49.2500 | 689.51 689.51 689.51 689.51 689.51
49.5000 | 689.51 689.51 689.51 689.51 689.51
49.7500 | 689.51 689.51 689.51 689.51 689.51
50.0000 | 689.51 689.51 689.51 689.51 689.51
50.2500 | 689.51 689.51 689.51 689.51 689.51
50.5000 | 689.51 689.51 689.51 689.51 689.51
50.7500 | 689.51 689.51 689.51 689.51 689.51
51.0000 | 689.51 689.51 689.51 689.51 689.51
51.2500 | 689.51 689.51 689.51 689.51 689.51
51.5000 | 689.51 689.51 689.51 689.51 689.51
51.7500 | 689.51 689.51 689.51 689.51 689.51
52.0000 | 689.51 689.51 689.51 689.51 689.51
52.2500 | 689.51 689.51 689.51 689.51 689.51
52.5000 | 689.51 689.51 689.51 689.51 689.51
52.7500 | 689.51 689.51 689.51 689.51 689.51
53.0000 | 689.51 689.51 689.51 689.51 689.51
53.2500 | 689.51 689.51 689.51 689.51 689.51
53.5000 | 689.51 689.51 689.51 689.51 689.50
53.7500 | 689.50 689.50 689.50 689.50 689.50
54.0000 | 689.50 689.50 689.50 689.50 689.50
54.2500 | 689.50 689.50 689.50 689.50 689.50
54.5000 | 689.50 689.50 689.50 689.50 689.50
54.7500 | 689.50 689.50 689.50 689.50 689.50
55.0000 | 689.50 689.50 689.50 689.50 689.50
55.2500 | 689.50 689.50 689.50 689.50 689.50
55.5000 | 689.50 689.50 689.50 689.50 689.50
55.7500 | 689.50 689.50 689.50 689.50 689.50
56.0000 | 689.50 689.50 689.50 689.50 689.50
56.2500 | 689.50 689.50 689.50 689.50 689.50
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Time-Elev Page 4.05
Name.... BMP 2 OUT Tag: 1 Event: 1 yr
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Storm... SCS TP II-6 MIN Tag: 1
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
56.5000 | 689.50 689.50 689.50 689.50 689.50
56.7500 | 689.50 689.50 689.50 689.50 689.50
57.0000 | 689.50 689.50 689.50 689.50 689.50
57.2500 | 689.50 689.50 689.50 689.50 689.50
57.5000 | 689.50 689.50 689.50 689.50 689.50
57.7500 | 689.50 689.50 689.50 689.50 689.50
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Vol: Elev-Volume Page 5.01
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
Title... BMP 1-SAND FILTER
USER DEFINED VOLUME RATING TABLE
Elevation Volume
(ft) (ac-ft)
---------------------
694.00 .000
695.00 .048
696.00 .115
697.00 .241
698.00 .438
698.50 .554
699.00 .681
699.50 .820
700.00 .972
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Vol: Elev-Volume Page 5.02
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
USER DEFINED VOLUME RATING TABLE
Elevation Volume
(ft) (ac-ft)
---------------------
689.50 .000
690.00 .312
691.00 1.018
692.00 1.796
692.50 2.214
693.00 2.623
694.00 3.597
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.01
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 694.00 ft
Increment = .20 ft
Max. Elev.= 700.00 ft
**********************************************
OUTLET CONNECTIVITY
**********************************************
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
User Defined Table P1 ---> TW .000 700.000
Weir-Rectangular ES ---> TW 698.500 700.000
Weir-Rectangular W1 ---> TW 697.900 700.000
TW SETUP, DS Channel
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.02
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = P1
Structure Type = User Defined Table
------------------------------------
ELEV-FLOW RATING TABLE
Elev, ft Flow, cfs
--------- ---------
694.00 .00
695.00 .11
696.00 .16
697.00 .20
698.00 .25
698.50 .27
699.00 .29
699.50 .31
700.00 .34
Structure ID = ES
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 698.50 ft
Weir Length = 20.00 ft
Weir Coeff. = 2.800000
Weir TW effects (Use adjustment equation)
Structure ID = W1
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 697.90 ft
Weir Length = 16.00 ft
Weir Coeff. = 3.100000
Weir TW effects (Use adjustment equation)
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.03
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.04
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = P1 (User Defined Table)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
694.00 .00 Free Outfall
694.20 .02 Free Outfall Interpolated from input table
694.40 .04 Free Outfall Interpolated from input table
694.60 .07 Free Outfall Interpolated from input table
694.80 .09 Free Outfall Interpolated from input table
695.00 .11 Free Outfall
695.20 .12 Free Outfall Interpolated from input table
695.40 .13 Free Outfall Interpolated from input table
695.60 .14 Free Outfall Interpolated from input table
695.80 .15 Free Outfall Interpolated from input table
696.00 .16 Free Outfall
696.20 .17 Free Outfall Interpolated from input table
696.40 .18 Free Outfall Interpolated from input table
696.60 .18 Free Outfall Interpolated from input table
696.80 .19 Free Outfall Interpolated from input table
697.00 .20 Free Outfall
697.20 .21 Free Outfall Interpolated from input table
697.40 .22 Free Outfall Interpolated from input table
697.60 .23 Free Outfall Interpolated from input table
697.80 .24 Free Outfall Interpolated from input table
697.90 .25 Free Outfall Interpolated from input table
698.00 .25 Free Outfall
698.20 .26 Free Outfall Interpolated from input table
698.40 .27 Free Outfall Interpolated from input table
698.50 .27 Free Outfall
698.60 .27 Free Outfall Interpolated from input table
698.80 .28 Free Outfall Interpolated from input table
699.00 .29 Free Outfall
699.20 .30 Free Outfall Interpolated from input table
699.40 .31 Free Outfall Interpolated from input table
699.60 .32 Free Outfall Interpolated from input table
699.80 .33 Free Outfall Interpolated from input table
700.00 .34 Free Outfall
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.05
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = ES (Weir-Rectangular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
694.00 .00 Free Outfall HW & TW below Inv.El.=698.500
694.20 .00 Free Outfall HW & TW below Inv.El.=698.500
694.40 .00 Free Outfall HW & TW below Inv.El.=698.500
694.60 .00 Free Outfall HW & TW below Inv.El.=698.500
694.80 .00 Free Outfall HW & TW below Inv.El.=698.500
695.00 .00 Free Outfall HW & TW below Inv.El.=698.500
695.20 .00 Free Outfall HW & TW below Inv.El.=698.500
695.40 .00 Free Outfall HW & TW below Inv.El.=698.500
695.60 .00 Free Outfall HW & TW below Inv.El.=698.500
695.80 .00 Free Outfall HW & TW below Inv.El.=698.500
696.00 .00 Free Outfall HW & TW below Inv.El.=698.500
696.20 .00 Free Outfall HW & TW below Inv.El.=698.500
696.40 .00 Free Outfall HW & TW below Inv.El.=698.500
696.60 .00 Free Outfall HW & TW below Inv.El.=698.500
696.80 .00 Free Outfall HW & TW below Inv.El.=698.500
697.00 .00 Free Outfall HW & TW below Inv.El.=698.500
697.20 .00 Free Outfall HW & TW below Inv.El.=698.500
697.40 .00 Free Outfall HW & TW below Inv.El.=698.500
697.60 .00 Free Outfall HW & TW below Inv.El.=698.500
697.80 .00 Free Outfall HW & TW below Inv.El.=698.500
697.90 .00 Free Outfall HW & TW below Inv.El.=698.500
698.00 .00 Free Outfall HW & TW below Inv.El.=698.500
698.20 .00 Free Outfall HW & TW below Inv.El.=698.500
698.40 .00 Free Outfall HW & TW below Inv.El.=698.500
698.50 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
698.60 1.77 Free Outfall H=.10; Htw=.00; Qfree=1.77;
698.80 9.20 Free Outfall H=.30; Htw=.00; Qfree=9.20;
699.00 19.80 Free Outfall H=.50; Htw=.00; Qfree=19.80;
699.20 32.80 Free Outfall H=.70; Htw=.00; Qfree=32.80;
699.40 47.82 Free Outfall H=.90; Htw=.00; Qfree=47.82;
699.60 64.60 Free Outfall H=1.10; Htw=.00; Qfree=64.60;
699.80 83.00 Free Outfall H=1.30; Htw=.00; Qfree=83.00;
700.00 102.88 Free Outfall H=1.50; Htw=.00; Qfree=102.88;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.06
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = W1 (Weir-Rectangular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
694.00 .00 Free Outfall HW & TW below Inv.El.=697.900
694.20 .00 Free Outfall HW & TW below Inv.El.=697.900
694.40 .00 Free Outfall HW & TW below Inv.El.=697.900
694.60 .00 Free Outfall HW & TW below Inv.El.=697.900
694.80 .00 Free Outfall HW & TW below Inv.El.=697.900
695.00 .00 Free Outfall HW & TW below Inv.El.=697.900
695.20 .00 Free Outfall HW & TW below Inv.El.=697.900
695.40 .00 Free Outfall HW & TW below Inv.El.=697.900
695.60 .00 Free Outfall HW & TW below Inv.El.=697.900
695.80 .00 Free Outfall HW & TW below Inv.El.=697.900
696.00 .00 Free Outfall HW & TW below Inv.El.=697.900
696.20 .00 Free Outfall HW & TW below Inv.El.=697.900
696.40 .00 Free Outfall HW & TW below Inv.El.=697.900
696.60 .00 Free Outfall HW & TW below Inv.El.=697.900
696.80 .00 Free Outfall HW & TW below Inv.El.=697.900
697.00 .00 Free Outfall HW & TW below Inv.El.=697.900
697.20 .00 Free Outfall HW & TW below Inv.El.=697.900
697.40 .00 Free Outfall HW & TW below Inv.El.=697.900
697.60 .00 Free Outfall HW & TW below Inv.El.=697.900
697.80 .00 Free Outfall HW & TW below Inv.El.=697.900
697.90 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
698.00 1.57 Free Outfall H=.10; Htw=.00; Qfree=1.57;
698.20 8.15 Free Outfall H=.30; Htw=.00; Qfree=8.15;
698.40 17.54 Free Outfall H=.50; Htw=.00; Qfree=17.54;
698.50 23.05 Free Outfall H=.60; Htw=.00; Qfree=23.05;
698.60 29.05 Free Outfall H=.70; Htw=.00; Qfree=29.05;
698.80 42.35 Free Outfall H=.90; Htw=.00; Qfree=42.35;
699.00 57.22 Free Outfall H=1.10; Htw=.00; Qfree=57.22;
699.20 73.52 Free Outfall H=1.30; Htw=.00; Qfree=73.52;
699.40 91.12 Free Outfall H=1.50; Htw=.00; Qfree=91.12;
699.60 109.94 Free Outfall H=1.70; Htw=.00; Qfree=109.94;
699.80 129.90 Free Outfall H=1.90; Htw=.00; Qfree=129.90;
700.00 150.94 Free Outfall H=2.10; Htw=.00; Qfree=150.94;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Composite Rating Curve Page 6.07
Name.... BMP 1

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
---------------- -------- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
694.00 .00 Free Outfall P1
694.20 .02 Free Outfall P1
694.40 .04 Free Outfall P1
694.60 .07 Free Outfall P1
694.80 .09 Free Outfall P1
695.00 .11 Free Outfall P1
695.20 .12 Free Outfall P1
695.40 .13 Free Outfall P1
695.60 .14 Free Outfall P1
695.80 .15 Free Outfall P1
696.00 .16 Free Outfall P1
696.20 .17 Free Outfall P1
696.40 .18 Free Outfall P1
696.60 .18 Free Outfall P1
696.80 .19 Free Outfall P1
697.00 .20 Free Outfall P1
697.20 .21 Free Outfall P1
697.40 .22 Free Outfall P1
697.60 .23 Free Outfall P1
697.80 .24 Free Outfall P1
697.90 .25 Free Outfall P1 +W1
698.00 1.82 Free Outfall P1 +W1
698.20 8.41 Free Outfall P1 +W1
698.40 17.80 Free Outfall P1 +W1
698.50 23.32 Free Outfall P1 +ES +W1
698.60 31.09 Free Outfall P1 +ES +W1
698.80 51.83 Free Outfall P1 +ES +W1
699.00 77.31 Free Outfall P1 +ES +W1
699.20 106.61 Free Outfall P1 +ES +W1
699.40 139.24 Free Outfall P1 +ES +W1
699.60 174.86 Free Outfall P1 +ES +W1
699.80 213.23 Free Outfall P1 +ES +W1
700.00 254.16 Free Outfall P1 +ES +W1
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.08
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 689.50 ft
Increment = .50 ft
Max. Elev.= 694.00 ft
**********************************************
OUTLET CONNECTIVITY
**********************************************
---> Forward Flow Only (UpStream to DnStream)
<--- Reverse Flow Only (DnStream to UpStream)
<---> Forward and Reverse Both Allowed
Structure No. Outfall E1, ft E2, ft
----------------- ---- ------- --------- ---------
Orifice-Circular OR ---> TW 689.500 694.000
Weir-Rectangular W1 ---> TW 692.500 694.000
Weir-Rectangular W2 ---> TW 690.650 694.000
Weir-Rectangular ES ---> TW 692.500 694.000
TW SETUP, DS Channel
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.09
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = OR
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 689.50 ft
Diameter = .6670 ft
Orifice Coeff. = .600
Structure ID = W1
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 692.50 ft
Weir Length = 3.00 ft
Weir Coeff. = 3.100000
Weir TW effects (Use adjustment equation)
Structure ID = W2
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 690.65 ft
Weir Length = 2.00 ft
Weir Coeff. = 3.100000
Weir TW effects (Use adjustment equation)
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Outlet Input Data Page 6.10
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = ES
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 692.50 ft
Weir Length = 19.00 ft
Weir Coeff. = 2.800000
Weir TW effects (Use adjustment equation)
Structure ID = TW
Structure Type = TW SETUP, DS Channel
------------------------------------
FREE OUTFALL CONDITIONS SPECIFIED
CONVERGENCE TOLERANCES...
Maximum Iterations= 30
Min. TW tolerance = .01 ft
Max. TW tolerance = .01 ft
Min. HW tolerance = .01 ft
Max. HW tolerance = .01 ft
Min. Q tolerance = .10 cfs
Max. Q tolerance = .10 cfs
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.11
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = OR (Orifice-Circular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
689.50 .00 Free Outfall Upstream HW & DNstream TW < Inv.El
690.00 .58 Free Outfall CRIT.DEPTH CONTROL Vh= .143ft Dcr= .357ft
CRIT.DEPTH
690.50 1.37 Free Outfall H =.67
690.65 1.52 Free Outfall H =.82
691.00 1.82 Free Outfall H =1.17
691.50 2.17 Free Outfall H =1.67
692.00 2.48 Free Outfall H =2.17
692.50 2.75 Free Outfall H =2.67
693.00 2.99 Free Outfall H =3.17
693.50 3.22 Free Outfall H =3.67
694.00 3.43 Free Outfall H =4.17
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.12
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = W1 (Weir-Rectangular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
689.50 .00 Free Outfall HW & TW below Inv.El.=692.500
690.00 .00 Free Outfall HW & TW below Inv.El.=692.500
690.50 .00 Free Outfall HW & TW below Inv.El.=692.500
690.65 .00 Free Outfall HW & TW below Inv.El.=692.500
691.00 .00 Free Outfall HW & TW below Inv.El.=692.500
691.50 .00 Free Outfall HW & TW below Inv.El.=692.500
692.00 .00 Free Outfall HW & TW below Inv.El.=692.500
692.50 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
693.00 3.29 Free Outfall H=.50; Htw=.00; Qfree=3.29;
693.50 9.30 Free Outfall H=1.00; Htw=.00; Qfree=9.30;
694.00 17.09 Free Outfall H=1.50; Htw=.00; Qfree=17.09;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.13
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = W2 (Weir-Rectangular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
689.50 .00 Free Outfall HW & TW below Inv.El.=690.650
690.00 .00 Free Outfall HW & TW below Inv.El.=690.650
690.50 .00 Free Outfall HW & TW below Inv.El.=690.650
690.65 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
691.00 1.28 Free Outfall H=.35; Htw=.00; Qfree=1.28;
691.50 4.86 Free Outfall H=.85; Htw=.00; Qfree=4.86;
692.00 9.72 Free Outfall H=1.35; Htw=.00; Qfree=9.72;
692.50 15.60 Free Outfall H=1.85; Htw=.00; Qfree=15.60;
693.00 22.34 Free Outfall H=2.35; Htw=.00; Qfree=22.34;
693.50 29.83 Free Outfall H=2.85; Htw=.00; Qfree=29.83;
694.00 38.01 Free Outfall H=3.35; Htw=.00; Qfree=38.01;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Individual Outlet Curves Page 6.14
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = ES (Weir-Rectangular)
--------------------------------------
Upstream ID = (Pond Water Surface)
DNstream ID = TW (Pond Outfall)
WS Elev,Device Q Tail Water Notes
---------------- --------------- --------------------------
WS Elev. Q TW Elev Converge
ft cfs ft +/-ft Computation Messages
-------- ------- -------- ----- --------------------------
689.50 .00 Free Outfall HW & TW below Inv.El.=692.500
690.00 .00 Free Outfall HW & TW below Inv.El.=692.500
690.50 .00 Free Outfall HW & TW below Inv.El.=692.500
690.65 .00 Free Outfall HW & TW below Inv.El.=692.500
691.00 .00 Free Outfall HW & TW below Inv.El.=692.500
691.50 .00 Free Outfall HW & TW below Inv.El.=692.500
692.00 .00 Free Outfall HW & TW below Inv.El.=692.500
692.50 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
693.00 18.81 Free Outfall H=.50; Htw=.00; Qfree=18.81;
693.50 53.20 Free Outfall H=1.00; Htw=.00; Qfree=53.20;
694.00 97.73 Free Outfall H=1.50; Htw=.00; Qfree=97.73;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Composite Rating Curve Page 6.15
Name.... BMP 2

File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
---------------- -------- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
689.50 .00 Free Outfall None contributing
690.00 .58 Free Outfall OR
690.50 1.37 Free Outfall OR
690.65 1.52 Free Outfall OR +W2
691.00 3.10 Free Outfall OR +W2
691.50 7.03 Free Outfall OR +W2
692.00 12.20 Free Outfall OR +W2
692.50 18.35 Free Outfall OR +W1 +W2 +ES
693.00 47.42 Free Outfall OR +W1 +W2 +ES
693.50 95.55 Free Outfall OR +W1 +W2 +ES
694.00 156.27 Free Outfall OR +W1 +W2 +ES
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Pond E-V-Q Table Page 7.01
Name.... BMP 1
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
LEVEL POOL ROUTING DATA
HYG Dir = W:\PONDPAK\16157\
Inflow HYG file = NONE STORED - BMP 1 IN 1
Outflow HYG file = NONE STORED - BMP 1 OUT 1
Pond Node Data = BMP 1
Pond Volume Data = BMP 1
Pond Outlet Data = BMP 1
No Infiltration
INITIAL CONDITIONS
----------------------------------
Starting WS Elev = 694.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. = .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Infilt. Q Total 2S/t + O
ft cfs ac-ft cfs cfs cfs
------------------------------------------------------------------------------
694.00 .00 .000 .00 .00 .00
694.20 .02 .010 .00 .02 4.64
694.40 .04 .019 .00 .04 9.28
694.60 .07 .029 .00 .07 13.92
694.80 .09 .038 .00 .09 18.56
695.00 .11 .048 .00 .11 23.21
695.20 .12 .061 .00 .12 29.78
695.40 .13 .075 .00 .13 36.34
695.60 .14 .088 .00 .14 42.91
695.80 .15 .102 .00 .15 49.48
696.00 .16 .115 .00 .16 56.05
696.20 .17 .141 .00 .17 68.25
696.40 .18 .166 .00 .18 80.45
696.60 .18 .191 .00 .18 92.65
696.80 .19 .216 .00 .19 104.85
697.00 .20 .241 .00 .20 117.05
697.20 .21 .281 .00 .21 136.09
697.40 .22 .320 .00 .22 155.13
697.60 .23 .359 .00 .23 174.17
697.80 .24 .399 .00 .24 193.21
697.90 .25 .418 .00 .25 202.73
698.00 1.82 .438 .00 1.82 213.81
698.20 8.41 .484 .00 8.41 242.77
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Pond E-V-Q Table Page 7.02
Name.... BMP 1
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
LEVEL POOL ROUTING DATA
HYG Dir = W:\PONDPAK\16157\
Inflow HYG file = NONE STORED - BMP 1 IN 1
Outflow HYG file = NONE STORED - BMP 1 OUT 1
Pond Node Data = BMP 1
Pond Volume Data = BMP 1
Pond Outlet Data = BMP 1
No Infiltration
INITIAL CONDITIONS
----------------------------------
Starting WS Elev = 694.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. = .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Infilt. Q Total 2S/t + O
ft cfs ac-ft cfs cfs cfs
------------------------------------------------------------------------------
698.40 17.80 .530 .00 17.80 274.53
698.50 23.32 .554 .00 23.32 291.23
698.60 31.09 .579 .00 31.09 311.31
698.80 51.83 .630 .00 51.83 356.69
699.00 77.31 .681 .00 77.31 406.81
699.20 106.61 .736 .00 106.61 463.07
699.40 139.24 .792 .00 139.24 522.66
699.60 174.86 .850 .00 174.86 586.41
699.80 213.23 .911 .00 213.23 654.11
700.00 254.16 .972 .00 254.16 724.36
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Type.... Pond E-V-Q Table Page 7.03
Name.... BMP 2
File.... W:\PONDPAK\16157\16157-OVERALL DETENTION ANALYSIS-7000BUA.PPW
LEVEL POOL ROUTING DATA
HYG Dir = W:\PONDPAK\16157\
Inflow HYG file = NONE STORED - BMP 2 IN 1
Outflow HYG file = NONE STORED - BMP 2 OUT 1
Pond Node Data = BMP 2
Pond Volume Data = BMP 2
Pond Outlet Data = BMP 2
No Infiltration
INITIAL CONDITIONS
----------------------------------
Starting WS Elev = 689.50 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. = .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Infilt. Q Total 2S/t + O
ft cfs ac-ft cfs cfs cfs
------------------------------------------------------------------------------
689.50 .00 .000 .00 .00 .00
690.00 .58 .312 .00 .58 151.40
690.50 1.37 .665 .00 1.37 323.12
690.65 1.52 .771 .00 1.52 374.55
691.00 3.10 1.018 .00 3.10 495.77
691.50 7.03 1.407 .00 7.03 687.97
692.00 12.20 1.796 .00 12.20 881.40
692.50 18.35 2.214 .00 18.35 1089.88
693.00 47.42 2.623 .00 47.42 1316.75
693.50 95.55 3.110 .00 95.55 1600.74
694.00 156.27 3.597 .00 156.27 1897.33
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017
Appendix A A-1
Index of Starting Page Numbers for ID Names
----- A -----
A-PRE DEV 1... 2.01, 3.01
A-PRE DEV 2... 2.05, 3.02

----- B -----
B-POST DEV 1... 3.03
B-POST DEV 2... 3.04
B-POST DEV 3... 2.08, 3.05
B-POST DEV 4... 2.12, 3.06
BMP 1... 5.01, 6.01, 6.04, 6.07,
7.01
BMP 2... 5.02, 6.08, 6.11, 6.15,
7.03
BMP 2 OUT 1... 4.01

----- W -----
Watershed... 1.01
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c)
The Isaacs Group
Compute Time: 10:28:39 Date: 09/26/2017