GRACE ONE CHURCH - 18098-Project-Calculations-9-19-18

Revised: October 2010
Page 1 of 3

Grace One Church
2609 Chestnut Lane
Union County, NC

Project Description:
This project requirements are to meet water quality and detention per the NC DEQ Design Manual specified by the Union
County Development Ordinance. The project entails the construction of a 15,000+ S.F. Church with a proposed parking
lot. The total project site area is 14.59 a.c. and proposed BUA is 1.95 acres (13.4% BUA). A Dry Detention SCM is
designed to route the 10yr and 25yr rainfall events to pre-developed flow rates. The Project is in an urbanized area and
can be categorized as low density based on criteria specified in 15A NCAC 02H.1017. A Vegetated swale is provided
prior to the detention basin which meets the LID design criteria.

DETENTION SUMMARY
Computer Method Used*: Pondpack

Pre (cfs) Post (cfs) Routed (cfs) Elevation (Comments)
10 yr. 3.53 15.77 0.93 710.87
25 yr. 5.59 20.85 1.84 711.31
100 yr. 9.04 29.04 4.26 711.77

Revised: October 2010
Page 2 of 3

PRE-DEVELOPED SUB-BASIN CALCULATIONS:
Sub-basin Name/Level: ___Pre-Developed Area_____

POST-DEVELOPED SUB-BASIN CALCULATIONS:
Sub-basin Name/Level: ___Post Developed Area______

Type of Flow Travel Length (ft.) Slope (%) Mannings (n) Time (min.)
Sheet Unpaved 100 1.00 0.24 19.07
Shallow Conc. (Unpaved) 571 2.80 3.52

TOTAL N/A N/A N/A Tc pre = 22.59
Acreage Land Use Soil Type Hydrologic Group CN Weighted CN
(Acreage/Total Area) x (CN)
3.27 Open Space Cecil B 61 40
1.48 Woods Cecil B 55 16
0.24 Impervious Cecil B 98 5
CNPre = 61
Type of Flow Travel Length (ft.) Slope (%) Mannings (n) Time (min.)
TOTAL N/A N/A N/A Tc post =5
Acreage Land Use Soil Type Hydrologic Group CN Weighted CN
(Acreage/Total Area) x (CN)
1.95 Impervious Cecil B 98 38
3.04 Open Space Cecil B 61 37
CNPost= 75

Revised: October 2010
Page 3 of 3

STORAGE / DISCHARGE CALCULATIONS
Stage Discharge
Co= orifice coefficient: Cw = weir coefficient. Orifice Area unit shall be square feet (sf).

Elevation Underground * Above Ground Total Acc. Volume
(cf) (Above and
Underground) Acc. Volume for all
Structures (cf)
Area (sq.
ft.)
Inc. Volume (cf) Acc. Volume (cf)
708.50 0 0 0 0 0
709 0 5745 1436 1436 1436
710 0 9644 7695 9131 9131
711 0 11340 10492 19623 19623
712 0 13200 12270 31893 31893
712.50 0 14038 6810 38702 38702
713 0 15288 7332 46034 46034
714 0 17604 16446 62480 62480
Elevation /
Stage
(ft)
Orifice 1
04167 ft.
708.67
Inv.
.136 Area
Co= 0.6

Weir 1
1.5 Ft..
711.00 Inv.
Cw= 3.1

Orifice 3
In.
Inv.
Area
Co=

Weir 4
Primary
Spillway
16 Ft.
712.25 Inv.
Cw= 3.10

Outlet
Control Pipe
__18___Dia
90 Length
_707.50_Inv.

Emergency
Spillway
10 Ft.
712.50 Inv.
Cw= 2.8

Total Q
(cfs)
708.75 0.02 0.02 0.02
709 0.20 0.20 0.20
710 0.70 0.70 0.70
711 0.96 0.96 0.96
711.25 1.01 0.58 1.59 1.59
712 1.16 4.65 5.81 5.81
712.25 1.21 6.50 7.70 7.70
712.50 1.25 8.54 5.62 15.41 15.41
712.75 1.29 10.76 15.89 27.95 3.50 31.45
713 1.33 13.15 29.20 43.68 9.90 53.58
714 1.49 24.16 104.06 129.71 51.44 181.15

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Soil Information

Hydrologic Soil Group—Union County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/28/2018
Page 1 of 4387960038796603879720387978038798403879900387996038800203880080387960038796603879720387978038798403879900387996038800203880080525380525440525500525560525620525680525740
525440 525500 525560 525620 525680 525740
35° 3' 47'' N 80° 43' 18'' W35° 3' 47'' N80° 43' 3'' W35° 3' 31'' N
80° 43' 18'' W35° 3' 31'' N
80° 43' 3'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,390 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 Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
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 17, Oct 3, 2017
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 18, 2011—Nov
25, 2017
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.
Hydrologic Soil Group—Union County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/28/2018
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
CeB2 Cecil gravelly sandy clay
loam, 2 to 8 percent
slopes, moderately
eroded
B 0.4 2.0%
CeC2 Cecil gravelly sandy clay
loam, 8 to 15 percent
slopes, moderately
eroded
B 2.5 11.2%
LdB2 Lloyd clay loam, 2 to 8
percent slopes,
moderately eroded
B 19.5 86.8%
Totals for Area of Interest 22.4 100.0%
Hydrologic Soil Group—Union County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/28/2018
Page 3 of 4
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—Union County, North Carolina
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
6/28/2018
Page 4 of 4

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Detention Calculations

DETENTION BASIN #1 VOLUME CALCULATIONS
GRACE ONE CHURCH, UNION COUNTY NC
See DA Maps for Pre and Post-developed drainage areas
Pre Developed Drainage Information:
Drainage Facility No.:1
Total Drainage Area, AD (Ac.) =4.99 See Drainage Area Exhibit DA2.0
Impervious Area (Ac.) =0.24 Total Proposed Impervious Area On-Site
Percent Impervious Area, IA =5
SCS Curve Number, CN = 61
Time of Concentration, tc =22.6 min See Pondpak Output
Post Developed Drainage Information:
Drainage Facility No.:1
Total Drainage Area, AD (Ac.) =4.99 See Drainage Area Exhibit DA3.0
Impervious Area (Ac.) =1.95 Total Proposed Impervious Area On-Site
Percent Impervious Area, IA =39
SCS Curve Number, CN = 75
Time of Concentration, tc =5 min
Stage-Storage Information:
Invert Elevation 6" Orifice @ Outlet Structure A2 708.5
Elevation Surface Area (ft2) Incremental Volume (ft
3)Cumulative
Volume (ft3)
Cumulative Volume
(ac-ft)
708.50 0 0 0 0.00000
709.00 5745 1,436 1,436 0.03297
710.00 9644 7,695 9,131 0.20961
711.00 11340 10,492 19,623 0.45048
712.00 13200 12,270 31,893 0.73216
712.50 14038 6,810 38,702 0.88848
713.00 15288 7,332 46,034 1.05679
714.00 17604 16,446 62,480 1.43434
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-DETENTION.xls
A-PRE DEVA-PRE OUTPRE-AREAB-POST DEVC-BASIN1POST-IND-POST OUTPOST OUT

Type.... Master Network Summary Page 1.01
Name.... Watershed
File.... W:\PONDPAK\18098\18098-DETENTION.PPW

MASTER DESIGN STORM SUMMARY

Default Network Design Storm File, ID STORMS.RNQ 6 Hour Storms

Total
Depth Rainfall
Return Event in Type RNF File RNF ID
------------ ------ ---------------- -------- ----------------
100 5.3400 Time-Depth Curve DETENT 100 Year 6 Hour
.25 4.3800 Time-Depth Curve DETENT 25 Year 6 Hour
.10 3.7220 Time-Depth Curve DETENT 10 Year 6 Hour

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 AREA 100 .656 3.3500 9.04
A-PRE DEV AREA 25 .421 3.3500 5.59
A-PRE DEV AREA 10 .281 3.3500 3.53

*A-PRE OUT JCT 100 .656 3.3500 9.04
*A-PRE OUT JCT 25 .421 3.3500 5.59
*A-PRE OUT JCT 10 .281 3.3500 3.53

B-POST DEV AREA 100 1.135 3.1000 29.04
B-POST DEV AREA 25 .814 3.1000 20.85
B-POST DEV AREA 10 .608 3.1000 15.77

C-BASIN1 IN POND 100 1.135 3.1000 29.04
C-BASIN1 IN POND 25 .814 3.1000 20.85
C-BASIN1 IN POND 10 .608 3.1000 15.77

C-BASIN1 OUT POND 100 1.123 3.6000 4.26 711.77 .667
C-BASIN1 OUT POND 25 .802 4.0500 1.84 711.31 .537
C-BASIN1 OUT POND 10 .596 4.3500 .93 710.87 .419

*D-POST OUT JCT 100 1.123 3.6000 4.26
*D-POST OUT JCT 25 .802 4.0500 1.84
*D-POST OUT JCT 10 .596 4.3500 .93

S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Design Storms Page 2.01
Name.... 6 Hour Storms

File.... W:\PONDPAK\RAINFALL\STORMS.RNQ
Title... Grace One Church - Union County

DESIGN STORMS SUMMARY

Design Storm File,ID = STORMS.RNQ 6 Hour Storms
Storm Tag Name = 100
Description: 100 Year 6 Hour
----------------------------------------------------------------------
Data Type, File, ID = Time-Depth Curve DETENT.RNF 100 Year 6 Hour
Storm Frequency = 100 yr
Total Rainfall Depth= 5.3400 in
Duration Multiplier = 1
Resulting Duration = 6.0000 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 6.0000 hrs
Storm Tag Name = .25
----------------------------------------------------------------------
Data Type, File, ID = Time-Depth Curve DETENT.RNF 25 Year 6 Hour
Storm Frequency = 25 yr
Total Rainfall Depth= 4.3800 in
Duration Multiplier = 1
Resulting Duration = 6.0000 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 6.0000 hrs
Storm Tag Name = .10
Description: 10 Year 6 Hour
----------------------------------------------------------------------
Data Type, File, ID = Time-Depth Curve DETENT.RNF 10 Year 6 Hour
Storm Frequency = 10 yr
Total Rainfall Depth= 3.7220 in
Duration Multiplier = 1
Resulting Duration = 6.0000 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 6.0000 hrs
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Tc Calcs Page 3.01
Name.... A-PRE DEV

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
TIME OF CONCENTRATION CALCULATOR
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

------------------------------------------------------------------------
Segment #1: Tc: TR-55 Shallow
Hydraulic Length 571.00 ft
Slope .028000 ft/ft
Unpaved
Avg.Velocity 2.70 ft/sec
Segment #1 Time: .0587 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Sheet
Mannings n .2400
Hydraulic Length 100.00 ft
2yr, 24hr P 3.1200 in
Slope .010000 ft/ft
Avg.Velocity .09 ft/sec
Segment #2 Time: .3178 hrs
------------------------------------------------------------------------
=========================
Total Tc: .3766 hrs
=========================
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Tc Calcs Page 3.02
Name.... A-PRE DEV

File.... W:\PONDPAK\18098\18098-DETENTION.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) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Runoff CN-Area Page 4.01
Name.... A-PRE DEV

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Pasture, Class B Soil 61 3.270 61.00
Woods, Class B Soil 55 1.480 55.00
Impervious 98 .240 98.00
COMPOSITE AREA & WEIGHTED CN ---> 4.990 61.00 (61)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Runoff CN-Area Page 4.02
Name.... B-POST DEV

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RUNOFF CURVE NUMBER DATA
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

--------------------------------------------------------------------------
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Impervious (BUA) 98 1.950 98.00
Open Space, Class B Soil, Good 61 3.040 61.00
COMPOSITE AREA & WEIGHTED CN ---> 4.990 75.46 (75)
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Time-Elev Page 5.01
Name.... C-BASIN1 OUT Tag: .10 Event: 10 yr
File.... W:\PONDPAK\18098\18098-DETENTION.PPW
Storm... 10 Year 6 Hour Tag: .10
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
2.5000 | 708.50 708.50 708.50 708.52 708.54
2.7500 | 708.57 708.63 708.71 708.84 709.01
3.0000 | 709.13 709.34 709.64 709.96 710.15
3.2500 | 710.28 710.39 710.46 710.52 710.57
3.5000 | 710.62 710.66 710.69 710.71 710.73
3.7500 | 710.75 710.77 710.79 710.80 710.81
4.0000 | 710.83 710.84 710.84 710.85 710.85
4.2500 | 710.86 710.86 710.86 710.87 710.87
4.5000 | 710.87 710.87 710.87 710.87 710.87
4.7500 | 710.86 710.86 710.86 710.85 710.85
5.0000 | 710.84 710.84 710.84 710.83 710.83
5.2500 | 710.82 710.82 710.81 710.81 710.80
5.5000 | 710.79 710.79 710.78 710.78 710.77
5.7500 | 710.76 710.76 710.75 710.74 710.74
6.0000 | 710.73 710.72 710.71 710.69 710.68
6.2500 | 710.66 710.65 710.63 710.62 710.61
6.5000 | 710.59 710.58 710.56 710.55 710.53
6.7500 | 710.52 710.50 710.49 710.47 710.46
7.0000 | 710.45 710.43 710.42 710.40 710.39
7.2500 | 710.38 710.36 710.35 710.34 710.32
7.5000 | 710.31 710.29 710.28 710.27 710.25
7.7500 | 710.24 710.23 710.22 710.20 710.19
8.0000 | 710.18 710.16 710.15 710.14 710.13
8.2500 | 710.11 710.10 710.09 710.08 710.06
8.5000 | 710.05 710.04 710.03 710.02 710.00
8.7500 | 709.99 709.97 709.96 709.94 709.92
9.0000 | 709.91 709.89 709.88 709.86 709.85
9.2500 | 709.83 709.82 709.80 709.79 709.77
9.5000 | 709.76 709.74 709.73 709.72 709.70
9.7500 | 709.69 709.67 709.66 709.65 709.63
10.0000 | 709.62 709.61 709.59 709.58 709.57
10.2500 | 709.56 709.54 709.53 709.52 709.51
10.5000 | 709.49 709.48 709.47 709.46 709.45
10.7500 | 709.44 709.42 709.41 709.40 709.39
11.0000 | 709.38 709.37 709.36 709.35 709.34
11.2500 | 709.33 709.32 709.31 709.30 709.29
11.5000 | 709.28 709.27 709.26 709.25 709.24
11.7500 | 709.23 709.22 709.21 709.20 709.20
12.0000 | 709.19 709.18 709.17 709.16 709.16
12.2500 | 709.15 709.14 709.13 709.13 709.12
12.5000 | 709.11 709.11 709.10 709.09 709.09
12.7500 | 709.08 709.07 709.07 709.06 709.06
13.0000 | 709.05 709.04 709.04 709.03 709.03
13.2500 | 709.02 709.02 709.01 709.01 709.00
13.5000 | 709.00 708.98 708.97 708.96 708.95
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Time-Elev Page 5.02
Name.... C-BASIN1 OUT Tag: .10 Event: 10 yr
File.... W:\PONDPAK\18098\18098-DETENTION.PPW
Storm... 10 Year 6 Hour Tag: .10
TIME vs. ELEVATION (ft)

Time | Output Time increment = .0500 hrs
hrs | Time on left represents time for first value in each row.
---------|--------------------------------------------------------------
13.7500 | 708.94 708.93 708.92 708.91 708.91
14.0000 | 708.90 708.89 708.88 708.88 708.87
14.2500 | 708.86 708.86 708.85 708.85 708.84
14.5000 | 708.84 708.83 708.83 708.82 708.82
14.7500 | 708.81 708.81 708.81 708.80 708.80
15.0000 | 708.80 708.79 708.79 708.79 708.78
15.2500 | 708.78 708.78 708.78 708.78 708.77
15.5000 | 708.77 708.77 708.77 708.77 708.76
15.7500 | 708.76 708.76 708.76 708.76 708.76
16.0000 | 708.76 708.75 708.75 708.75 708.75
16.2500 | 708.75 708.75 708.75 708.75 708.75
16.5000 | 708.75 708.74 708.74 708.74 708.74
16.7500 | 708.74 708.74 708.74 708.74 708.74
17.0000 | 708.74 708.74 708.74 708.73 708.73
17.2500 | 708.73 708.73 708.73 708.73 708.73
17.5000 | 708.73 708.73 708.73 708.73 708.73
17.7500 | 708.73 708.73 708.72 708.72 708.72
18.0000 | 708.72 708.72 708.72 708.72 708.72
18.2500 | 708.72 708.72 708.72 708.72 708.72
18.5000 | 708.72 708.72 708.72 708.71 708.71
18.7500 | 708.71 708.71 708.71 708.71 708.71
19.0000 | 708.71 708.71 708.71 708.71 708.71
19.2500 | 708.71 708.71 708.71 708.71 708.71
19.5000 | 708.71 708.71 708.71 708.71 708.70
19.7500 | 708.70 708.70 708.70 708.70 708.70
20.0000 | 708.70 708.70 708.70 708.70 708.70
20.2500 | 708.70 708.70 708.70 708.70 708.70
20.5000 | 708.70 708.70 708.70 708.70 708.70
20.7500 | 708.70 708.70 708.70 708.70 708.70
21.0000 | 708.69 708.69 708.69 708.69 708.69
21.2500 | 708.69 708.69 708.69 708.69 708.69
21.5000 | 708.69 708.69 708.69 708.69 708.69
21.7500 | 708.69 708.69 708.69 708.69 708.69
22.0000 | 708.69 708.69 708.69 708.69 708.69
22.2500 | 708.69 708.69 708.69 708.69 708.69
22.5000 | 708.69 708.69 708.69 708.69 708.69
22.7500 | 708.69 708.69 708.68 708.68 708.68
23.0000 | 708.68 708.68 708.68 708.68 708.68
23.2500 | 708.68 708.68 708.68 708.68 708.68
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Vol: Elev-Volume Page 6.01
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
USER DEFINED VOLUME RATING TABLE
Elevation Volume
(ft) (ac-ft)
---------------------
708.50 .000
709.00 .033
710.00 .210
711.00 .450
712.00 .732
712.50 .888
713.00 1.057
714.00 1.434
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Outlet Input Data Page 7.01
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
REQUESTED POND WS ELEVATIONS:
Min. Elev.= 708.50 ft
Increment = .25 ft
Max. Elev.= 714.00 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 1 ---> TW 708.666 714.000
Weir-Rectangular 2 ---> TW 711.000 714.000
Weir-Rectangular 3 ---> TW 712.250 714.000
Weir-Rectangular 4 ---> TW 712.500 714.000
TW SETUP, DS Channel
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Outlet Input Data Page 7.02
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = 1
Structure Type = Orifice-Circular
------------------------------------
# of Openings = 1
Invert Elev. = 708.67 ft
Diameter = .4167 ft
Orifice Coeff. = .600
Structure ID = 2
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 711.00 ft
Weir Length = 1.50 ft
Weir Coeff. = 3.100000
Weir TW effects (Use adjustment equation)
Structure ID = 3
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 712.25 ft
Weir Length = 14.50 ft
Weir Coeff. = 3.100000
Weir TW effects (Use adjustment equation)
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Outlet Input Data Page 7.03
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
OUTLET STRUCTURE INPUT DATA
Structure ID = 4
Structure Type = Weir-Rectangular
------------------------------------
# of Openings = 1
Crest Elev. = 712.50 ft
Weir Length = 10.00 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) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Individual Outlet Curves Page 7.04
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = 1 (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
-------- ------- -------- ----- --------------------------
708.50 .00 Free Outfall HW & TW below invert
708.67 .00 Free Outfall Upstream HW & DNstream TW < Inv.El
708.75 .02 Free Outfall CRIT.DEPTH CONTROL Vh= .019ft Dcr= .065ft
CRIT.DEPTH
709.00 .20 Free Outfall CRIT.DEPTH CONTROL Vh= .096ft Dcr= .238ft
CRIT.DEPTH
709.25 .40 Free Outfall H =.38
709.50 .52 Free Outfall H =.63
709.75 .61 Free Outfall H =.88
710.00 .70 Free Outfall H =1.13
710.25 .77 Free Outfall H =1.38
710.50 .84 Free Outfall H =1.63
710.75 .90 Free Outfall H =1.88
711.00 .96 Free Outfall H =2.13
711.25 1.01 Free Outfall H =2.38
711.50 1.06 Free Outfall H =2.63
711.75 1.11 Free Outfall H =2.88
712.00 1.16 Free Outfall H =3.13
712.25 1.21 Free Outfall H =3.38
712.50 1.25 Free Outfall H =3.63
712.75 1.29 Free Outfall H =3.88
713.00 1.33 Free Outfall H =4.13
713.25 1.37 Free Outfall H =4.38
713.50 1.41 Free Outfall H =4.63
713.75 1.45 Free Outfall H =4.88
714.00 1.49 Free Outfall H =5.13
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Individual Outlet Curves Page 7.05
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = 2 (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
-------- ------- -------- ----- --------------------------
708.50 .00 Free Outfall HW & TW below Inv.El.=711.000
708.67 .00 Free Outfall HW & TW below Inv.El.=711.000
708.75 .00 Free Outfall HW & TW below Inv.El.=711.000
709.00 .00 Free Outfall HW & TW below Inv.El.=711.000
709.25 .00 Free Outfall HW & TW below Inv.El.=711.000
709.50 .00 Free Outfall HW & TW below Inv.El.=711.000
709.75 .00 Free Outfall HW & TW below Inv.El.=711.000
710.00 .00 Free Outfall HW & TW below Inv.El.=711.000
710.25 .00 Free Outfall HW & TW below Inv.El.=711.000
710.50 .00 Free Outfall HW & TW below Inv.El.=711.000
710.75 .00 Free Outfall HW & TW below Inv.El.=711.000
711.00 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
711.25 .58 Free Outfall H=.25; Htw=.00; Qfree=.58;
711.50 1.64 Free Outfall H=.50; Htw=.00; Qfree=1.64;
711.75 3.02 Free Outfall H=.75; Htw=.00; Qfree=3.02;
712.00 4.65 Free Outfall H=1.00; Htw=.00; Qfree=4.65;
712.25 6.50 Free Outfall H=1.25; Htw=.00; Qfree=6.50;
712.50 8.54 Free Outfall H=1.50; Htw=.00; Qfree=8.54;
712.75 10.76 Free Outfall H=1.75; Htw=.00; Qfree=10.76;
713.00 13.15 Free Outfall H=2.00; Htw=.00; Qfree=13.15;
713.25 15.69 Free Outfall H=2.25; Htw=.00; Qfree=15.69;
713.50 18.38 Free Outfall H=2.50; Htw=.00; Qfree=18.38;
713.75 21.21 Free Outfall H=2.75; Htw=.00; Qfree=21.21;
714.00 24.16 Free Outfall H=3.00; Htw=.00; Qfree=24.16;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Individual Outlet Curves Page 7.06
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = 3 (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
-------- ------- -------- ----- --------------------------
708.50 .00 Free Outfall HW & TW below Inv.El.=712.250
708.67 .00 Free Outfall HW & TW below Inv.El.=712.250
708.75 .00 Free Outfall HW & TW below Inv.El.=712.250
709.00 .00 Free Outfall HW & TW below Inv.El.=712.250
709.25 .00 Free Outfall HW & TW below Inv.El.=712.250
709.50 .00 Free Outfall HW & TW below Inv.El.=712.250
709.75 .00 Free Outfall HW & TW below Inv.El.=712.250
710.00 .00 Free Outfall HW & TW below Inv.El.=712.250
710.25 .00 Free Outfall HW & TW below Inv.El.=712.250
710.50 .00 Free Outfall HW & TW below Inv.El.=712.250
710.75 .00 Free Outfall HW & TW below Inv.El.=712.250
711.00 .00 Free Outfall HW & TW below Inv.El.=712.250
711.25 .00 Free Outfall HW & TW below Inv.El.=712.250
711.50 .00 Free Outfall HW & TW below Inv.El.=712.250
711.75 .00 Free Outfall HW & TW below Inv.El.=712.250
712.00 .00 Free Outfall HW & TW below Inv.El.=712.250
712.25 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
712.50 5.62 Free Outfall H=.25; Htw=.00; Qfree=5.62;
712.75 15.89 Free Outfall H=.50; Htw=.00; Qfree=15.89;
713.00 29.20 Free Outfall H=.75; Htw=.00; Qfree=29.20;
713.25 44.95 Free Outfall H=1.00; Htw=.00; Qfree=44.95;
713.50 62.82 Free Outfall H=1.25; Htw=.00; Qfree=62.82;
713.75 82.58 Free Outfall H=1.50; Htw=.00; Qfree=82.58;
714.00 104.06 Free Outfall H=1.75; Htw=.00; Qfree=104.06;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Individual Outlet Curves Page 7.07
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
RATING TABLE FOR ONE OUTLET TYPE
Structure ID = 4 (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
-------- ------- -------- ----- --------------------------
708.50 .00 Free Outfall HW & TW below Inv.El.=712.500
708.67 .00 Free Outfall HW & TW below Inv.El.=712.500
708.75 .00 Free Outfall HW & TW below Inv.El.=712.500
709.00 .00 Free Outfall HW & TW below Inv.El.=712.500
709.25 .00 Free Outfall HW & TW below Inv.El.=712.500
709.50 .00 Free Outfall HW & TW below Inv.El.=712.500
709.75 .00 Free Outfall HW & TW below Inv.El.=712.500
710.00 .00 Free Outfall HW & TW below Inv.El.=712.500
710.25 .00 Free Outfall HW & TW below Inv.El.=712.500
710.50 .00 Free Outfall HW & TW below Inv.El.=712.500
710.75 .00 Free Outfall HW & TW below Inv.El.=712.500
711.00 .00 Free Outfall HW & TW below Inv.El.=712.500
711.25 .00 Free Outfall HW & TW below Inv.El.=712.500
711.50 .00 Free Outfall HW & TW below Inv.El.=712.500
711.75 .00 Free Outfall HW & TW below Inv.El.=712.500
712.00 .00 Free Outfall HW & TW below Inv.El.=712.500
712.25 .00 Free Outfall HW & TW below Inv.El.=712.500
712.50 .00 Free Outfall H=.00; Htw=.00; Qfree=.00;
712.75 3.50 Free Outfall H=.25; Htw=.00; Qfree=3.50;
713.00 9.90 Free Outfall H=.50; Htw=.00; Qfree=9.90;
713.25 18.19 Free Outfall H=.75; Htw=.00; Qfree=18.19;
713.50 28.00 Free Outfall H=1.00; Htw=.00; Qfree=28.00;
713.75 39.13 Free Outfall H=1.25; Htw=.00; Qfree=39.13;
714.00 51.44 Free Outfall H=1.50; Htw=.00; Qfree=51.44;
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Composite Rating Curve Page 7.08
Name.... C-BASIN1

File.... W:\PONDPAK\18098\18098-DETENTION.PPW
***** COMPOSITE OUTFLOW SUMMARY ****
WS Elev, Total Q Notes
---------------- -------- Converge -------------------------
Elev. Q TW Elev Error
ft cfs ft +/-ft Contributing Structures
-------- ------- -------- ----- --------------------------
708.50 .00 Free Outfall None contributing
708.67 .00 Free Outfall None contributing
708.75 .02 Free Outfall 1
709.00 .20 Free Outfall 1
709.25 .40 Free Outfall 1
709.50 .52 Free Outfall 1
709.75 .61 Free Outfall 1
710.00 .70 Free Outfall 1
710.25 .77 Free Outfall 1
710.50 .84 Free Outfall 1
710.75 .90 Free Outfall 1
711.00 .96 Free Outfall 1 +2
711.25 1.59 Free Outfall 1 +2
711.50 2.71 Free Outfall 1 +2
711.75 4.13 Free Outfall 1 +2
712.00 5.81 Free Outfall 1 +2
712.25 7.70 Free Outfall 1 +2 +3
712.50 15.41 Free Outfall 1 +2 +3 +4
712.75 31.45 Free Outfall 1 +2 +3 +4
713.00 53.58 Free Outfall 1 +2 +3 +4
713.25 80.20 Free Outfall 1 +2 +3 +4
713.50 110.61 Free Outfall 1 +2 +3 +4
713.75 144.36 Free Outfall 1 +2 +3 +4
714.00 181.15 Free Outfall 1 +2 +3 +4
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Pond E-V-Q Table Page 8.01
Name.... C-BASIN1
File.... W:\PONDPAK\18098\18098-DETENTION.PPW
LEVEL POOL ROUTING DATA
HYG Dir = W:\PONDPAK\18098\
Inflow HYG file = NONE STORED - C-BASIN1 IN 100
Outflow HYG file = NONE STORED - C-BASIN1 OUT 100
Pond Node Data = C-BASIN1
Pond Volume Data = C-BASIN1
Pond Outlet Data = C-BASIN1
No Infiltration
INITIAL CONDITIONS
----------------------------------
Starting WS Elev = 708.50 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
------------------------------------------------------------------------------
708.50 .00 .000 .00 .00 .00
708.67 .00 .011 .00 .00 5.30
708.75 .02 .016 .00 .02 7.99
709.00 .20 .033 .00 .20 16.16
709.25 .40 .077 .00 .40 37.73
709.50 .52 .121 .00 .52 59.22
709.75 .61 .165 .00 .61 80.69
710.00 .70 .210 .00 .70 102.15
710.25 .77 .270 .00 .77 131.37
710.50 .84 .330 .00 .84 160.58
710.75 .90 .390 .00 .90 189.79
711.00 .96 .450 .00 .96 218.99
711.25 1.59 .521 .00 1.59 253.71
711.50 2.71 .591 .00 2.71 288.91
711.75 4.13 .662 .00 4.13 324.42
712.00 5.81 .732 .00 5.81 360.18
712.25 7.70 .810 .00 7.70 399.90
712.50 15.41 .888 .00 15.41 445.44
712.75 31.45 .973 .00 31.45 502.20
713.00 53.58 1.057 .00 53.58 565.07
713.25 80.20 1.151 .00 80.20 637.37
713.50 110.61 1.246 .00 110.61 713.47
713.75 144.36 1.340 .00 144.36 792.90
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018
Type.... Pond E-V-Q Table Page 8.02
Name.... C-BASIN1
File.... W:\PONDPAK\18098\18098-DETENTION.PPW
LEVEL POOL ROUTING DATA
HYG Dir = W:\PONDPAK\18098\
Inflow HYG file = NONE STORED - C-BASIN1 IN 100
Outflow HYG file = NONE STORED - C-BASIN1 OUT 100
Pond Node Data = C-BASIN1
Pond Volume Data = C-BASIN1
Pond Outlet Data = C-BASIN1
No Infiltration
INITIAL CONDITIONS
----------------------------------
Starting WS Elev = 708.50 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
------------------------------------------------------------------------------
714.00 181.15 1.434 .00 181.15 875.37
S/N: C21B02A06A82
PondPack Ver. 7.5 (786c) Compute Time: 10:46:19 Date: 09/19/2018

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Storm Drain Calculations

Grace One Church, Union County NC
I. STORM DRAINAGE CALCULATIONS
Refer Storm Drainage Area Exhibit Map
Rational Method used for pipe sizing.
A minimum time of concentration of 5 minutes has been assumed in
determining a rainfall intensity of 7.01 for the 10 year storm events
STORM RUN B & C
AREA ROOF DRAIN TO DI B3
A= 0.05 acres
I= 7.01 in/hour
C= 0.95
Q = (C)(I)(A) = .3 cfs
Q (total)= .3 cfs
Capacity of 6" Roof Drain 6 " HDPE @ 2.00% = .9 cfs > .3 cfs
AREA B3
A= 1.20 acres
I= 7.01 in/hour
C= 0.85
Q = (C)(I)(A) = 7.2 cfs
Q (total)= 7.5 cfs
Capacity of DI B3/CB B2 18 " HDPE @ 1.00% = 11.4 cfs > 7.5 cfs
AREA ROOF B2
A= 0.04 acres
I= 7.01 in/hour
C= 0.95
Q = (C)(I)(A) = .3 cfs
Q (total)= .3 cfs
Capacity of Roof Drain to CB B2 6 " HDPE @ 2.00% = .9 cfs > .3 cfs
AREA B2
A= 1.32 acres
I= 7.01 in/hour
C= 0.85
Q = (C)(I)(A) = 7.9 cfs
Q (total)= 15.6 cfs
Capacity of CB B2/CB B1 24 " HDPE @ 0.61% = 19.1 cfs > 15.6 cfs
AREA ROOF TO YI C1
A= 0.15 acres
I= 7.01 in/hour
C= 0.95
Q = (C)(I)(A) = 1.0 cfs
Q (total)= 1.0 cfs
Capacity of 8" HDPE Roof Drain 8 " HDPE @ 2.00% = 1.9 cfs > 1.0 cfs
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-STORM.xls
Grace One Church, Union County NC
I. STORM DRAINAGE CALCULATIONS
Refer Storm Drainage Area Exhibit Map
Rational Method used for pipe sizing.
A minimum time of concentration of 5 minutes has been assumed in
determining a rainfall intensity of 7.01 for the 10 year storm events
AREA C1
A= 0.04 acres
I= 7.01 in/hour
C= 0.50
Q = (C)(I)(A) = .1 cfs
Q (total)= 1.1 cfs
Capacity of YI C1/CB B1 12 " HDPE @ 2.00% = 5.5 cfs > 1.1 cfs
AREA B1
A= 0.76 acres
I= 7.01 in/hour
C= 0.76
Q = (C)(I)(A) = 4.0 cfs
Q (total)= 20.8 cfs
Capacity of CB B1/CB A5 24 " HDPE @ 0.74% = 21.1 cfs > 20.8 cfs
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-STORM.xls
Grace One Church, Union County NC
I. STORM DRAINAGE CALCULATIONS
Refer Storm Drainage Area Exhibit Map
Rational Method used for pipe sizing.
A minimum time of concentration of 5 minutes has been assumed in
determining a rainfall intensity of 7.01 for the 10 year storm events
STORM RUN A & D
AREA A6
A= 0.61 acres
I= 7.01 in/hour
C= 0.85
Q = (C)(I)(A) = 3.6 cfs
Q (total)= 3.6 cfs
Capacity of CB A6/CB A5 12 " HDPE @ 2.82% = 6.5 cfs > 3.6 cfs
AREA A5
A= 0.28 acres
I= 7.01 in/hour
C= 0.85
Q = (C)(I)(A) = 1.7 cfs
Q (total)= 26.1 cfs
Capacity of CB A5/JB A4 24 " HDPE @ 2.05% = 35.1 cfs > 26.1 cfs
AREA D2
A= 0.13 acres
I= 7.01 in/hour
C= 0.50
Q = (C)(I)(A) = .5 cfs
Q (total)= .5 cfs
Capacity of YI D2/JB D1 8 " HDPE @ 1.91% = 1.8 cfs > .5 cfs
AREA ROOF to JB D1
A= 0.12 acres
I= 7.01 in/hour
C= 0.95
Q = (C)(I)(A) = .8 cfs
Q (total)= .8 cfs
Capacity of 6" Roof Drain 8 " HDPE @ 2.00% = 1.9 cfs > .8 cfs
AREA ROOF to JB D1 (FUTURE)
A= 0.49 acres
I= 7.01 in/hour
C= 0.95
Q = (C)(I)(A) = 3.3 cfs
Q (total)= 4.1 cfs
Capacity of JB D1/JB A4 12 " HDPE @ 2.77% = 6.4 cfs > 4.1 cfs
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-STORM.xls
Grace One Church, Union County NC
I. STORM DRAINAGE CALCULATIONS
Refer Storm Drainage Area Exhibit Map
Rational Method used for pipe sizing.
A minimum time of concentration of 5 minutes has been assumed in
determining a rainfall intensity of 7.01 for the 10 year storm events
Q (total)= 30.2 cfs
Capacity of JB A4/FES A3 24 " RCP @ 1.66% = 31.6 cfs > 30.2 cfs
Q (total)= 4.3 cfs (See 100 yr Storm Pondpak Results)
Capacity of OS A2/FES A1 18 " RCP @ 1.61% = 14.4 cfs > 4.3 cfs
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-STORM.xls

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Skimmer Basin Calculations

THE ISAACS GROUP
Grace One Church, Union County NC
SEDIMENT CONTROL
Skimmer Basin #1 Phase 1
5.03 AC.
3.42 AC.
6156 CF (DRAINAGE AC. (DISTURBED) x 1,800)
19622.8 CF (SEE BELOW)
0.55 (WEIGHTED RUNOFF COEFFICIENT)
19.45 CFS (C x 7.03 x DRAINAGE AREA)
16 FT
0.55 FT
<1.0', THEREFORE O.K.
SEDIMENT BASIN STORAGE CALCULATION:

Area (sq.ft.)Inc. Volume
(cf)
Acc. Volume
(cf)
708.50 0.0 0.0 0.0
709.00 5745.0 1436.3 1436.3
710.00 9644.0 7694.5 9130.8
711.00 11340.0 10492.0 19622.8
712.00 13200.0 12270.0 31892.8
712.50 14038.0 6809.5 38702.3
713.00 15288.0 7331.5 46033.8
714.00 17604.0 16446.0 62479.8

SEDIMENT TRAPPING EFFICIENCY
75% Trap efficiency per Barfield and Clar equation:
Surface area required at design flow (acres) = (435) * peak inflow rate (cfs)
Surface area required at design flow (acres) = 0.1942 AC.
8460.1 SF
Surface area provided at design flow (acres) =11340 SF
DRAINAGE AREA TO BASIN=
Elevation
Above Ground
DISTURBED AREA TO BASIN=
REQUIRED BASIN VOLUME=
VOLUME PROVIDED=
C=
Q10=
SPILLWAY WIDTH=
h=
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-SKIMMER BASIN-PH1.xls
Calculate Skimmer SizeBasin Volume in Cubic Feet6,156 Cu.FtSkimmer Size 2.0InchDays to Drain*3 Days Orifice Radius0.8Inch[es]Orifice Diameter1.5Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feet0 FeetVOLUME 0Cu. Ft.Bottom dimensions in feet0 0 FeetDepth in feet0 Feet
THE ISAACS GROUP
Grace One Church, Union County NC
SEDIMENT CONTROL
Skimmer Basin #1 Phase 2
5.32 AC.
3.71 AC.
6678 CF (DRAINAGE AC. (DISTURBED) x 1,800)
19622.8 CF (SEE BELOW)
0.55 (WEIGHTED RUNOFF COEFFICIENT)
20.57 CFS (C x 7.03 x DRAINAGE AREA)
16 FT
0.57 FT
<1.0', THEREFORE O.K.
SEDIMENT BASIN STORAGE CALCULATION:

Area (sq.ft.)Inc. Volume
(cf)
Acc. Volume
(cf)
708.50 0.0 0.0 0.0
709.00 5745.0 1436.3 1436.3
710.00 9644.0 7694.5 9130.8
711.00 11340.0 10492.0 19622.8
712.00 13200.0 12270.0 31892.8
712.50 14038.0 6809.5 38702.3
713.00 15288.0 7331.5 46033.8
714.00 17604.0 16446.0 62479.8

SEDIMENT TRAPPING EFFICIENCY
75% Trap efficiency per Barfield and Clar equation:
Surface area required at design flow (acres) = (435) * peak inflow rate (cfs)
Surface area required at design flow (acres) = 0.2054 AC.
8947.9 SF
Surface area provided at design flow (acres) =11340 SF
Elevation
Above Ground
DISTURBED AREA TO BASIN=
REQUIRED BASIN VOLUME=
VOLUME PROVIDED=
C=
Q10=
SPILLWAY WIDTH=
h=
DRAINAGE AREA TO BASIN=
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-SKIMMER BASIN-PH2.xls
Calculate Skimmer SizeBasin Volume in Cubic Feet6,678 Cu.FtSkimmer Size 2.0InchDays to Drain*3 Days Orifice Radius0.8Inch[es]Orifice Diameter1.6Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feet0 FeetVOLUME 0Cu. Ft.Bottom dimensions in feet0 0 FeetDepth in feet0 Feet
THE ISAACS GROUP
FLARED END SECTION RIP RAP APRON DESIGN
GRACE ONE CHURCH.
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]
FES A1 FES A3
D 18 24
Q 4.27 30.17
Do 1.5 2
3Do 4.5 6
La 10 18
W 11.5 20
d50 0.333 0.6
IIIMinimum Tailwater Conditions d (in.) Q (cfs)IFES A1 18 4.27 »IIFES A3 24 30.17 »10'L x 11.5'W x 12"D CLASS B APRON18'L x 20'W x 18"D CLASS B APRONDescription of ApronP:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-STORM.xls

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Rip Rap Calculation

Grace One Church

2609 Chestnut Lane
Union County, North Carolina

Bouancy Calculations

Riser Height = 5.9 ft
Riser Interior Dimension = 4.0 ft SQARE
Riser Wall Thickness = 6.0 in
Cross Sectional Area of Riser = 25.0 sf
Area of Conc. = 8.0 sf
Vol. of riser = 148 cf
Wt. of H 2O displaced =9235 lbs
Conc. pad thickness = 24 in
Conc. pad width/length = 10.0 ft
Vol. of conc. pad = 200 cf
Wt. of H 2O displaced =12480 lbs
Total Wt. of H 2O displaced =21715
Unit wt. of concrete (pcf) = 150
Wt. of conc. pad (lb.) = 30000
Wt. of conc. box (lb.) = 7104
Total Wt. of conc. (lb.) = 37104
Factor of safety = wt. Conc. Pad + Riser
wt. Of H2O displaced
F.S.= 1.71
CONCRETE ANCHOR BOUANCY CALCULATION
FOR OUTLET STRUCTURE A2
P:\Active Projects\Ecclesia Construction\Grace One Church 18098\Engineering\Calculations\18098-Riser
Bouancy.xls