SW3191104_2019.10.22-TLE Waxhaw Calcs_11/19/2019

Stormwater and Erosion Control Measures Calculations
For
The Learning Experience
Waxhaw, NC
Date: October 22, 2019
CES Project #7292
Prepared By: CES Group Engineers, LLP
274 N Highway 16, Suite 300
Denver, NC 28037
704.489.1500
ENOINEERS SURVEYORS SG EVTI5T5

The Learning Experience - Waxhaw
SWM Narrative
The proposed project includes construction of a Day Care Facility with associated parking lot, drives,
sidewalks and underground sand filter.
The existing contributing drainage area to the proposed underground sand filter consists of open grassed
areas and woods. The pre -development drainage area is 0.22 acres. The drainage area has HSG B and D
soils which results in a CN value of 77. The pre -development time of concentration was calculated to be
18 minutes (see attached Tc calculations).
The proposed contributing drainage area to the proposed underground sand filter consists of grass open
space, proposed buildings, sidewalks, parking lots, drives synthetic turf and dumpster pad. For purposes
of this analysis the drainage area was divided into impervious and open space areas. The post -
development drainage area is 1.01 acres. The drainage area has HSG B and D soils which results in a
weighted CN value of 91. The post -development impervious percentage for the drainage area is 85%. The
post -development time of concentration was assumed to be 5 minutes.
The proposed underground sand filter was modeled in HydroCAD. The sand filter will provide water
quality treatment of the first 1.0" of rainfall over the entire contributing drainage area based on the
maximum buildout of the site. The sand filter will also safely pass the peak flows from the 2-yr and 10-yr,
24-hour storm events.
The sand filter will have a control chamber with a bypass weir for storm events larger than 1.0". The
proposed sand filter is designed to provide enough storage volume for 75 of the required water quality
volume for the drainage area. The sand filter will have a 6" perforated PVC underdrain at the bottom of a
1.5' deep sand layer. The sand filter as proposed is consist of 6 Oldcastle Precast Storm Capture units, 3
units for the sediment chamber and 3 units for the filter chamber. The sand filter will discharge in the
northeast corner of the site onto an appropriately sized Class B riprap apron before water leaves the site
and flows onto the adjacent HOA parcel. There is an existing drainage feature on the adjacent parcel.

The Learning Experience - Waxhaw
Erosion and Sediment Control Narrative
Proiect Descrintion:
The proposed project is described as a 1.54+/- acre parcel with (PID# 06156003 as recognized by Union
County GIS) owned by Charlene G Carter of 6622 Loblolly Circle Waxhaw, NC 28173. The parcel is to be
developed by GSG Holdings. The project consists of a proposed Day Care Facility with associated
parking lot, drives, sidewalks, dumpster pad, retaining wall, road improvements and underground sand
filter. This erosion control plan includes the proposed grading and storm drainage for the site.
The total disturbed area is approximately 1.85 acres. There will be three to one (3:1) maximum side
slopes throughout the project.
The erosion and sediment control plan is designed to conform to The North Carolina Department of
Environmental Quality (UNION COUNTY) Erosion and Sediment Control Planning and Design Manual.
This includes all measures necessary to provide protection from the calculated maximum peak rate of
runoff from the ten (10) year, twenty (24) hour design storm. The plans are designed to contain erosion
on the project site and minimize overall erosion and sediment conforming to the existing topography of
the land as much as local design standards and established good engineering practices will allow. Storm
drainage conveyance and drainage pipes are designed to Union County standards with a calculated
maximum peak rate of runoff from a ten (10) year design storm. Design storm precipitations are based on
the Point Precipitation Frequency Estimates from the National Oceanic and Atmospheric Administration,
Waxhaw, NC location.
Site Location:
The property is located at 1425 Providence Road S Waxhaw, NC 28173. The parcel will be accessed by
one entrance off of Providence Rd S.
Site Descriotion:
The overall site consists primarily of woodland and grass area. To the east of the site lies a developed
residential parcel. To the north lies a residential HOA parcel. To the west lies Providence Rd S. To the
south of the site lies a developed residential parcel.
The property generally falls from southwest to northeast. The low elevation on the site is approximately
648.5 feet in the northeast corner and rises up to a high elevation of approximately 667 feet in the
southwest corner. Existing slopes are generally 5% or flatter on the western portion (front) of the site and
steepen to as much as 15% in the eastern (rear) portion of the site.
According to FEMA Firm Panel 3710446500J the project site lies in a Zone X, areas outside the 0.2%
annual chance floodplain.
The drainage pattern within the site shows that in general the site drains from the southwest corner to the
northeast corner of the site..
Runoff from the mass grading construction will be contained within temporary diversion ditches and a
sediment trap in the north portion of the site. The stilled water will then be discharged to an existing swale
along the northern property line.
-1-

Soils:
Soil Profiles: The soils for the project area, as defined by the United States Department of Agriculture as
follows:
Cecil gravelly sandy clay loam, (CeB2) -- —50%
Helena fine sandy loam, (HeB) -- —50%
See the attached soil report and map.
Pre and Post Development Storm Water Runoff
The pre development runoff was calculated using the HydroCAD modeling software.
The post development runoff was calculated as follows for the 2 year, 10
Year, 25 year.
Storm
2 YR
10YR
25YR
Predevelopment Runoff
0.37
0.71
0.93
cfs
Post Development
4.46
6.94
8.46
Runoff cfs)
Planned Erosion and Sediment Control Practices:
(See Erosion Control Plan Sheets)
1. Temporary Sediment Fence
Sediment silt fences will be installed along the down grade side of all fill slopes for the site.
2. Temporary Wattle
Wattles will be installed in all the Providence Rd ditch to slow velocity of flow and be maintained
until appropriate ditch liner is installed and vegetation is established.
3. Outlet Stabilization Structure
End Section with Rip Rap Outlet Protection
4. Provide Rip Rap outlet protections to reduce velocity of flow.
5. Temporary Gravel Construction Entrance
A temporary gravel contraction entrance will be installed at the entrance.
6. Temporary Diversions
Temporary diversions are placed above the cut banks to prevent surface runoff from eroding
these banks. A temporary diversion will be constructed along the fill side of the road bed to
prevent runoff from traveling over the fill slope.
7. Baffles
Baffles are to be installed in all sediment traps and basins to aid in the settling of sediment.
8. Sediment Traps
A Sediment Trap is constructed to capture sediment laden runoff and retain for a minimum of 72
hours using a skimmer dewatering device, primary spillway, and emergency spillway. Basin
serves drainage areas up to five (5) acres.
-2-

Overall Construction Sequence:
1. Obtain plan approval from NCDEQ.
2. Install a rain gauge on the site and maintain a written record of amounts of all rainfall and dates.
3. Set up pre -construction conference on -site with erosion control inspector and engineer to discuss
erosion control measures.
4. Mark construction limits.
5. Install silt fence, silt fence outlets and construction entrance.
6. Call NCDEQ for first inspection.
7. Install temporary diversion ditches, sediment trap and temporary wattles.
8. Call for on -site inspection by erosion control inspector. When erosion control measures are
approved, begin construction.
9. All erosion control measures must be installed before construction begins.
10. Clear and grub site, dispose of any trees, trimming, stumps and brush.
11. Allow for runoff to enter drop inlets and maintain inlet protection.
12. Contractor to remove only enough silt fence to access fill area. Silt fence to be reinstalled after
hauling and grading is completed.
13. Complete site construction within the project limits and stabilize site.
14. Maintain and record self inspections per 15A NCAC 04b.0131 of NCDEQ for each phase of
project to ensure erosion and sedimentation control plan is being followed.
15. Maintain storm water inspection log per NPDES permit.
16. Erosion and sedimentation control measures must be inspected at least once per 7 calendar days
and within 24 hours of a rainfall event greater than 0.5 inches per 24 hour period.
17. After the site is stabilized, install permanent vegetation on the disturbed areas and remove
temporary erosion control devices. Spot seed and mulch all resulting bare areas.
18. Remove all erosion control devices, spreading and seeding accumulated sediment. Removal of
erosion control measures shall be approved by erosion control inspector.
19. Request pre -final inspection for "punch list" items.
20. Request final inspection from NCDEQ.
-3-

Soil Map —Union County, North Carolina
(TLE Waxhaw)
520740 520750 520760 520770 520780 520790 520830 520810 520820 520830
34o 59' 32" N
34o 59' 32" N
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8
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Aft
Soil Map may not he valiel at this scale.
it
34o 59' 28" N �j
i I
34o 59' 28" N
520740 520750 520760 520770 .7. 520790 520800 5.10
5.20 520830 520840
Map Scale: 1:685 if printed on A portrait (8.5" x 11") sheet.
Meters
$
N 0 10 20 40 60
$
Feet
0 30 60 120 180
Map projection: Web Mercator Conermordinates: WGS84 Edge tics: UTM Zone 17N WGS84
USDA
Natural Resources Web Soil Survey
9/12/2019
Conservation Service National Cooperative Soil Survey
Pagel of 3

MAP LEGEND
Area of Interest (AOI)
0
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
0
Landfill
A.
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
o
Sodic Spot
Soil Map —Union County, North Carolina
(TLE Waxhaw)
MAP INFORMATION
Spoil Area
The soil surveys that comprise your AOI were mapped at
1:24,000.
Stony Spot
th
Very Stony Spot
Warning: Soil Map may not be valid at this scale.
Wet Spot
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
4�
Other
line placement. The maps do not show the small areas of
Special Line Features
contrasting soils that could have been shown at a more detailed
scale.
Water Features
Streams and Canals
Please rely on the bar scale on each map sheet for map
measurements.
Transportation
—
Rails
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
. 0
Interstate Highways
Coordinate System: Web Mercator (EPSG:3857)
US Routes
Maps from the Web Soil Survey are based on the Web Mercator
Major Roads
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Local Roads
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
Background
Aerial Photography
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 18, Sep 10, 2018
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.
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Page 2 of 3

Soil Map —Union County, North Carolina
TLE Waxhaw
Map Unit Legend
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
CeB2
Cecil gravelly sandy clay loam,
2 to 8 percent slopes,
moderately eroded
0.9
57.1 %
HeB
Helena fine sandy loam, 2 to 8
percent slopes
0.7
42.9%
Totals for Area of Interest
1.6
100.0%
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Page 3 of 3

Map Unit Description: Cecil gravelly sandy clay loam, 2 to 8 percent slopes, moderately
eroded ---Union County, North Carolina
TLE Waxhaw
Union County, North Carolina
CeB2—Cecil gravelly sandy clay loam, 2 to 8 percent slopes,
moderately eroded
Map Unit Setting
National map unit symbol: 2mx87
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Cecil, moderately eroded, and similar soils: 85 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Cecil, Moderately Eroded
Setting
Landform: Interfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Saprolite derived from granite and gneiss and/or
schist
Typical profile
Ap - 0 to 6 inches: gravelly sandy clay loam
Bt - 6 to 40 inches: clay
BC - 40 to 55 inches: clay loam
C - 55 to 80 inches: sandy loam
Properties and qualities
Slope: 2 to 8 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):
Moderately high to high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 8.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Pagel of 2

Map Unit Description: Cecil gravelly sandy clay loam, 2 to 8 percent slopes, moderately
eroded ---Union County, North Carolina
TLE Waxhaw
Hydric soil rating: No
Data Source Information
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 18, Sep 10, 2018
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Page 2 of 2

Map Unit Description: Helena fine sandy loam, 2 to 8 percent slopes ---Union County, North
Carolina
TLE Waxhaw
Union County, North Carolina
HeB—Helena fine sandy loam, 2 to 8 percent slopes
Map Unit Setting
National map unit symbol: 3wl4
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Helena and similar soils: 85 percent
Minor components: 4 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Helena
Setting
Landform: Ridges
Landform position (two-dimensional): Summit, footslope
Down -slope shape: Concave
Across -slope shape: Concave
Parent material: Saprolite derived from granite and gneiss and/or
schist
Typical profile
Ap - 0 to 8 inches: fine sandy loam
Bt - 8 to 45 inches: clay
BC - 45 to 80 inches: sandy loam
Properties and qualities
Slope: 2 to 8 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Moderately well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat):
Moderately low to moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 18 to 30 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.8 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: D
Hydric soil rating: No
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Pagel of 2

Map Unit Description: Helena fine sandy loam, 2 to 8 percent slopes ---Union County, North
Carolina
TLE Waxhaw
Minor Components
Worsham, undrained
Percent of map unit: 2 percent
Landform: Depressions
Landform position (two-dimensional): Footslope
Down -slope shape: Concave
Across -slope shape: Concave
Hydric soil rating: Yes
Wehadkee, undrained
Percent of map unit: 2 percent
Landform: Depressions on flood plains
Down -slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: Yes
Data Source Information
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 18, Sep 10, 2018
USDA Natural Resources Web Soil Survey 9/12/2019
Conservation Service National Cooperative Soil Survey Page 2 of 2

Temporary Sediment Trap #1
0.83 Disturbed Area (Acres)
3.8 Peak Flow from 10-year Storm (cfs)
2988 Required Volume ft3
1636 Required Surface Area ft2
28.6 Suggested Width ft
57.2 Suggested Length ft
30 Trial Top Width at Spillway Invert ft
60 Trial Top Length at Spillway Invert ft
2 Trial Side Slope Ratio Z:1
3 Trial Depth ft (1.5 feet below grade + 2 to 3.5 feet above grade)
18 Bottom Width ft
48 Bottom Length ft
864 Bottom Area ft2
3924 Actual Volume ft3 Okay
1800 Actual Surface Area ft2 Okay
10 Trial Weir Length ft
0.5 Trial Depth of Flow ft
10.6 Spillway Capacity cfs Okay

TLE Waxhaw
Project Number:
7292
Description
Original Dale:
9/25/19
DB:
SC
Revision Dale:
1/0/00
PM:
TC
Location
I Inlet I
1 Areas I
Storm Runoff
I
I
Pipe Sizing Calculations
I I
I I Pipe Input/Cover Calculations
Percent 1 Percent 1 Composite 1
From I To I I I I p I
(acres) Pervious Imperviou Runoff
Structure I Structure) I (%) I s (%) I Coeff. Cc I
I (in/hr)
1 nlet 1 Combined I I I Pi e I I
I I I I Pipe 1 p 1 Dtheo I
Discharge Q Discharge Material n Length Size (in)
I (cfs) I Opipe (cfs): :Slope (%)I (ft) I (in) I
I I I
I I Pipe I I
I Vfull I Capacity I I
O/O-full d/dm ratio
I (fps) I O-full I I
I I (cfs) I I
Pipe
I I I Time 1 Actual
I I I _
vN-full Actual (min) Pipe Structure
I I Vpipe 1 Full 1 Time 1 Pipe 1 Pipe 1 Rim 1 Cover
I I (fps) 1 Cond. 1 (min) 11nv. Out Inv. In 1 Elevation 1
Depth Of
(Based
on Rim)
Pipe
1 Pipe 1 Material
1 Material) Class
DI-6
DI-5
0.18 1
50%
50%
0.63
7.55
0.86
0.86
0.013 1.00% 89.27 7.0
12
4.5
3.57
0.24
0.30
0.74
3.36 0.33 0.44 658.26 657.37 661.58
2.07
HDPE
DI-5
CB-4
0.03 1
70%
30%
0.50
7.55
0.11
1.84 1
0.013 1 2.00% 1 91.39 8.2
15
7.5
9.17
0.20
0.30
1 0.74
1 5.53 0.20 0.28 657.27 655.44 662.70
3.93
RCP Class 111
CB-4 1
SF-2 1 0.05 1
10% 1 90% 1
0.89 1
7.55
1 0.32
1 2.16 1
0.013 1 2.00% 1 17.021 8.7 1
15
1 7.5 1
9.15 1
0.24
1 0.30
1 0.74
1 5.52 1 0.04 1 0.05 1 655.341655.001 661.06 1
4.22
1 RCP I Class III
CB-3
SF-2
0.42
20%
80%
0.82
7.55
2.59
2.59
0.013 2.01 % 50.77 9.3 1
15
1 7.5 1
9.18 1
0.28
1 0.35
1 0.82
1 6.13 1 0.11 1 0.14 1 654.02 1653.001 658.49 1
2.97
1 RCP Class III
I
I I
I I
I
I
I I
I I I I
I I
I
I
I
I I I I I I I
I I
SF-2
HW-1
0.00
100%
0.95
7.55
0.00
7.71 1
0.013 1 2.99% 1 20.101 13.0 1
15
1 9.1 1
11.19 1
0.69
1 0.60
1 1.07
1 8.08 1 0.04 1 0.04 1 651.00 1650.401 659.84 1
7.34
1 RCP 1 Class 111
JD-7A I
DI-7
I 0.00 I
0%
1 100% I
0.95 I
7.55
I 0.00
I 0.00 1
0.013 1 1.00% 1114.271 0.0 1
6
1 2.9 1
0.56 1
0.00
1 0.00
1 0.00
1 0.00 1 0.67 I#DIV/0!1659.601658.461 662.64 1
2.54
1 HDPE
DI-7
CO-2A
0.09
0%
1 100% 1
0.95
7.55
0.64
0.64 1
0.013 1 1.01% 1172.561 6.3 1
8
1 3.5 1
1.22 1
0.53
1 0.50
1 0.99
1 3.46 1 0.82 1 0.83 1 659.00 1657.251 662.51 1
2.84
1 HDPE
CO-2A
SF-2
0.07
0%
100%
0.95
7.55
0.47
1.11
0.013 4.11% 30.42 5.9
8
7.0
2.46
0.45
0.45
0.94
6.61 0.07 0.08 657.25 656.00 662.19
4.27
HDPE
I
I I
I I
I
I
I I
I I I I
I I
I
I
I
I I I I I I I
I I
A2
Al
0.09
0%
100%
0.95
7.55
0.65
0.65 1
0.013 1 1.00% 164.07 6.3 1
8
1 3.5 1
1.21 1
0.54
1 0.50
1 0.99
1 3.44 1 0.79 1 0.80 1 660.50 658.86 663.17 1
2.00
1 HDPE
A3
Al
0.03
0%
100%
0.95
7.55
0.22
0.22 1
0.013 1 1.00% 1 34.891 4.2 1
6
1 2.9 1
0.56 1
0.39
1 0.40
1 0.87
1 2.50 1 0.20 1 0.23 1 659.21 1658.861 663.17 1
3.46
1 HDPE
Al :
DI-5
: 0.00 :
0%
I 100% :
0.95 :
7.55
: 0.00
I 0.87 1
0.013 1 1.02% 1 13.731 7.0 1
8
1 3.5 1
1.22 1
0.71
1 0.60
1 1.07
1 3.11 1 0.07 1 0.07 1 658.86 1658.721 663.06 1
3.53
1 HDPE I
B2 1
B1
1 0.09 1
0%
1 100% 1
0.95 1
7.55
1 0.65
1 0.65 1
0.013 1 1.00% 1168.081 6.3 1
8
1 3.5 1
1.21 1
0.54
1 0.50
1 0.99
1 3.44 1 0.81 1 0.82 1 660.50 1658.821 663.17 1
2.00
1 HDPE I
B3
B1
0.03
0%
100%
0.95 1
7.55
0.22
0.22 1
0.013 1 1.00% 1 36.881 4.2 1
6
1 2.9 1
0.56 1
0.39
1 0.40
1 0.87
1 2.50 0.21 1 0.25 1 659.19 1658.821 663.17 1
3.48
1 HDPE
B1
SF-2
0.00
0%
100%
0.95
7.55
0.00
0.87
0.013 6.37% 52.15 5.0
8
1 8.8 1
3.06
0.29
0.35
0.82
7.18 0.10 0.12 658.82 655.50 663.00
3.51
HDPE
I
I I
I I
I
I
I I
I I I I
I I
I
I
I
I I I I I I I
I I
1,x-xx
xx.xx Hold receiving pipe invert
xxx.xx Pipe invert higher than receiving
Drop in inverts

Rip -Rap Apron Summary Table
I I
Outlet I Discharge I Do (in)
I (cfs) I
Minimum TW Condition
Wi=Do + La W2=3*Do W2 H=(2/3)*Do
tdSo(ft) I La (ft) I Wi (ft) I (ft) I * T(ft) I H (ft)
HW-1 I 7.7 I 18 I I I 11.50 I 4.50 I 1.125 I 1.00
I I I I I I I I
I I I I I I I I
I I I I I I I I
dmax=1.5*d50
*T=1.5*dmax (Min. *T=10") Apron Thickness = *T
Min. La=10 ft
H=Depth of apron

NRCS TRAVEL TIME CALCULATIONS
TYPE
SHEET
Flow Length (ft)
94
Upstream Elev (ft)
665
Downstream Elev (ft)
662
Mannings n
0.400
Slope (ft/ft)
0.032
P2 (in)
3.12
Travel Time, Tt (min)
17.2
TYPE
=CTIOP
Flow Length (ft)
164
Upstream Elev (ft)
662
Downstream Elev (ft)
648.5
Surface Type
Unpaved
Slope (ft/ft)
0.082
V (ft/s)
4.63
Travel Time, Tt (min)
0.59
Travel Time, Tt (min)
0.59
TYPE
SECTION
1
Channel Type
N/A
Width, b (ft)
Flow Depth, h (ft)
Top Width, T (ft)
Side Slope, z
Pipe Dia., D (ft)
Area (ft)
N/A
Wetted Perimeter (ft)
N/A
Hydraulic Radius (ft)
N/A
Flow Length (ft)
Upstream Elev (ft)
Downstream Elev (ft)
Mannings n
Slope (ft/ft)
N/A
Velocity, V (ft/s)
N/A
Travel Time, Tt (min)
N/A
Travel Time, Tt (min)
TOTAL Tc (min)
DATE:
9/25/2019
PROJECT:
TLE Waxhaw
PROJECT M
7292.0819
DESIGNER:
SMC
CATCHMENT: Pre -Development
SHALLOW CONCENTRATED
2 3 4
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
OPEN CHANNEL
2 3
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A

Sand Filter Design
DATE: 9/25/2019
PROJECT: TLE Waxhaw
PROJECT #: 7292.0819
DESIGNER: SMC
1 SITE DATA
Area to Sand Filter (sf)
Area to Sand Filter (ac)
Impervious (sf)
Impervious (ac)
Pervious (ac)
% Impervious
2 WATER QUALITY CALCULATIONS
Runoff Coefficient, Rv
WQv (ac-ft)
WQv (in)
WQv (cf)
75% WQv (cf)
3 HYDROLOGIC PARAMETERS
Area (sf)
Area (ac)
CN
CN, (modified, P=1 in)
Travel Time Tt (min)
NCDEQ Stormwater Design Manual
Chapter 6 - Sand Filter (November 7, 2018)
Pre-Dev
Post-Dev
Target Sand Filter Effectiveness
9,675
43,990
0.22
1.01
Detention Time (days)* 2
0
37439
Media Depth 1.5 ft
0.00
0.86
Removal Rate 85% TSS
0.22
0.15
0%
85%
'measured from the midpoint of the design storm
0.82
R = 0.05 + 0.009 » /
0.069
1.0»R *A
WQv —
0.82
12
2,991
2,243
'allowed for sand filters per MDC 3
Pre-Dev
Post-Dev
9,675
43,990
0.22
1.01
77
91
98
98
18
5
1000
CN = [10 + 5P + 10WQV — 10(WQV2 + 1.25WQvP)os]
4 WATER QUALITY PEAK FLOW
WQp (cfs) *From HydroCAD
5 CHANNEL PROTECTION VOLUME
S (in)
P (in, 1-yr, 24-hr))
Qd (in)
CPv (ac-ft)
6 RELEASE RATES
Post-Dev
1000
0.99
S =
2.58
CN-10
(2.58 — 0.25)z
1.
Qa =
(P �
0.14
A0.8S)
Qd
CPv =
CURVE NUMBER CALCULATION
Pre -Development
Area
HSG
CN
CN*Area
Impervious
0
D
98
0
Open Space
0.19247
D
80
15.39761249
Open Space
0.02964
B
61
1.807874197
17.2055
Sum
77
CN Weighted
Post -Development
Area
HSG
CN
CN*Area
Impervious
0.35742
D
98
35.02667585
Impervious
0.50207
B
98
49.20247934
Open Space
0.12528
B
61
7.641804408
91.871
Sum
91
CN Weighted
Drawdown Time (hr)
Water Quality 51 51 Hour Drawdown (48 hours beyond 3 hours)
Channel Protection — —
Post-Dev (43,560 » WQv)
WQ, Release (cfs) 0.016 WQv Release Rate = (DrawdownTime * 3,600)
CPv Release (cfs) #VALUE! (43,560 * CPv)
CPv Release Rate = (DrawdownTime * 3,600)

Sand Filter Design
7 SEDIMENTATION AND FILTRATION CHAMBERS
SEDIMENTATION
Volume (ac-ft)
0.010
0.2 » WQ
Volume (ft)
449
FILTRATION
Filter Bed Depth, df (ft)
1.5
Permeability, k (ft/day)
3.5
Max height of water, h, _ (ft)
3.60
Avg height of water, hf (ft)
1.80
Filter Drain Time, $ (days)
2.125
Filter Surface Area, Af(ftZ)
183
Af
» df
=
k (h+ d f� tf
,
Length -to -Width Ratio
3
Length (ft)
23.4
Width (ft)
7.8
Sandfilter Product
Oldcastle
StormCapture
Inside area per unit (sf)
105.0
75% WQv (cf)
2243.4
Total # units required
5.9
8 STAGE -STORAGE
Volume (ac-ft)
Stage (ft) Area (ft)
Area (ac)
Avg Area (ac)
Increm.
Cumulative
652.5 630
0.0145
0.0000
0.0000
0.0000
653 630
0.0145
0.0145
0.0072
0.0072
654 630
0.0145
0.0145
0.0145
0.0217
655 630
0.0145
0.0145
0.0145
0.0362
656.1 630
0.0145
0.0145
0.0159
0.0521
9 STAGE -DISCHARGE
Top of Filter Media
652.5
Stage Height
Discharge (cfs)
652.5 0
0.000
653 0.5
0.010
654 1.5
0.015
655 2.5
0.020
656.1 3.6
0.025
657 4.5
0.030
10 WATER QUALITY AND CHANNEL PROTECTION ELEVATIONS
WATER QUALITY ELEVATION
Stage
Storage (ac-ft)
655
0.0362
_ _
_ 656.06_
0.0515
656.1
0.0521
11 DRAWDOWN AND UNDERDRAIN DESIGN
Minimum Drawdown Discharge
m (ft') 2,243
Drawdown (cfs) 0.016
Compute Perforation Capacity
No. of pipes
2
Length of each pipe (ft)
42
Number of cleanouts per pipe
2
Rows per foot
4
Holes per Row
4
Number of perforations
1280
Percent clogged
50%
Unclogged Perforations
640
Storage Depth (ft)
3.6
Perforation Capacity (cfs)
0.0070
Total Capacity (cfs)
4.4845
CHANNEL PROTECTION ELEVATION
Stage Storage (ac-ft)
#N/A
L _ !N/A _ J 0.1415
#N/A
Compute Underdrain Capacity
Underdrain Slope (ft/ft)
0.01
Underdrain Size (in)
6
Underdrain A (fe)
0.196
Underdrain P (ft)
1.571
Underdrain Capacity (cfs)
0.56
Unclogged Capacity (cfs)
0.28
'Needs to be greater than 1' depth
discharge and min. drawdown
capacity

9/12/2019
Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Waxhaw, North Carolina, USA* '"
Latitude: 34.9917*, Longitude:-80.7722*
Elevation: 661.12 ft**
'source: ESRI Maps
** source: USGS C
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, I Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average
recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
0.417
0.492
0.571
0.629
0.696
0.742
0.784
0.821
0.864
0.895
5-min
(0.384-0.453)
(0.453-0.536)
(0.525-0.622)
(0.577-0.683)
(0.635-0.754)
(0.674-0.804)
(0.708-0.849)
(0.739-0.890)
(0.770-0.938)
(0.791-0.973)
0.666
0.787
0.915
1.01
1.11
1.18
1.25
1.30
1.37
1.41
10-min
(0.614-0.723)
(0.724-0.857)
(0.840-0.996)
(0.922-1.09)
1 (1.01-1.20)
1 (1.07-1.28) 11
(1.13-1.35) 11
(1.17-1.41)
1 (1.22-1.48)
1 (1.25-1.53)
0.832
0.990
1.16
1.27
1.41
1.50
1.57
1.64
1.72
1.77
15-min
(0.768-0.904)
(0.911-1.08) 11
(1.06-1.26)
1 (1.17-1.38)
1 (1.28-1.52)
1 (1.36-1.62) 11
(1.42-1.71) 11
(1.48-1.78)
1 (1.53-1.87)
1 (1.56-1.92)
1.14
1.37
1.64
1.85
2.08
2.25
2.41
2.56
2.74
2.86
30-min
(1 .05-1.24)
(1.26-1.49)
(1.51-1.79)
(1.69-2.00)
(1.90-2.26)
(2.05-2.44)
(2.18-2.61)
(2.30-2.77)
(2.44-2.97)
(2.53-3.12)
1.42
1.72
2.11
2.40
2.77
3.05
3.32
3.59
3.93
4.18
60-min
(1.31-1.55)
(1.58-1.87)
(1.94-2.30)
(2.20-2.61)
(2.53-3.00)
(2.77-3.31)
(3.00-3.60)
(3.23-3.89)
(3.50-4.26)
(3.70-4.55)
1.65
1.99
2.47
2.83
3.30
3.66
4.02
4.38
4.85
5.21
2-hr
(1.51-1.80)
(1.82-2.18)
(2.25-2.70)
(2.58-3.09)
(3.00-3.60)
(3.31-3.99)
(3.61-4.38)
(3.91-4.78)
(4.29-5.29)
(4.57-5.70)
3-hr
1.75
(1 .60-1.93)
2.11
(1.93-2.32)
2.63
(2.40-2.89)
3.04
(2.76-3.33)
3.59
(3.25-3.92)
4.02
(3.62-4.39)
4.46
(3.99-4.86)
4.91
(4.36-5.36)
5.53
(4.85-6.04)
6.03
(5.22-6.59)
2.10
2.53
3.16
3.66
4.33
4.87
5.43
6.00
6.80
7.43
6-hr
(1 .93-2.31)
(2.32-2.78)
(2.89-3.47)
(3.34-4.00)
(3.934.72)
(4.39-5.31)
(4.85-5.91)
(5.32-6.53)
(5.94-7.39)
(6.42-8.08)
2.48
3.00
3.76
4.37
5.21
5.90
6.62
7.37
8.43
9.29
12-hr
(2.28-2.72)
(2.76-3.30)
(3.44-4.12)
(3.99-4.78)
(4.72-5.69)
(5.31-6.43)
(5.89-7.20)
(6.49-8.01)
(7.31-9.15)
(7.94-10.1)
2.94
3.54
4.44
5.16
6.16
6.96
7.79
8.66
9.87
10.8
24-hr
(2.72-3.17)
(3.28-3.83)
(4.11-4.81)
(4.77-5.59)
(5.66-6.66)
(6.38-7.53)
(7.12-8.43)
(7.88-9.38)
(8.92-10.7)
(9.75-11.8)
2iiay
3.46
(3.20-3.74)
4.16
(3.86-4.51)
5.19
(4.80-5.63)
6.01
(5.54-6.51)
7.13
(6.56-7.73)
8.04
(7.37-8.71)
8.97
(8.20-9.73)
9.95
(9.05-10.8)
11.3
(10.2-12.3)
12.4
(11.1-13.5)
3iiay
3.67
(3.40-3.96)
4.40
(4.09-4.76)
5.46
(5.06-5.91)
6.31
(5.83-6.82)
7.47
(6.88-8.08)
8.40
(7.72-9.09)
9.37
(8.58-10.1)
10.4
(9.46-11.3)
11.8
(10.7-12.8)
12.9
(11.6-14.0)
3.87
4.65
5.74
6.61
7.81
8.77
9.77
10.8
12.3
13.4
aiiay
(3.60-4.18)
(4.32-5.02)
(5.33-6.20)
(6.11-7.13)
(7.21-8.43)
(8.07-9.48)
(8.96-10.6)
(9.87-11.7)
(11.1-13.3)
(12.1-14.6)
7iiay
4. 0 4981
5.01 5674
6. 0---7300
6. 647699
8. 4 9639
9.07-610.5
10.0-111.7
11 0-12.9
12.4- 4.6
1315- 5.9
10-day
5.13
(4 .81-5.49)
6.11
(5.72-6.53)
7.35
(6.87-7.86)
8.33
(7.78-8.91)
9.66
(8.99-10.3)
10.7
(9.95-11.5)
11.8
( 10.9-12.6)
12.9
( 11.9-13.8)
14.3
( 13.2-15.4)
15.6
( 14.3-16.7)
6.86
8.09
9.56
10.7
12.3
13.5
14.8
16.0
17.7
19.1
20-day
(6.46-7.30)
(7.61-8.62)
(8.98-10.2)
(10.1-11.4)
(11.5-13.1)
(12.6-14.4)
(13.8-15.8)
(14.9-17.1)
(16.4-19.0)
(17.6-20.5)
8.41
9.89
11.5
12.8
14.4
15.7
17.0
18.2
19.9
21.2
30-day
(7.94-8.93)
(9.34-10.5)
(10.9-12.2)
(12.0-13.6)
(13.6-15.3)
(14.7-16.7)
(15.9-18.1)
(17.0-19.4)
(18.5-21.3)
(19.7-22.7)
10.678
45-day
10.1--111.1
11 8- 3.0
1315- 4.9
14.8- 6.4
16.4- 8.2
(17..7
9.7
18?9- 1.1
20.11 2.5
21?6- 4.3
2224 5.7
12.6
14.7
16.6
18.1
20.0
21.5
22.9
24.2
26.0
27.3
60-day
(12 0-13.2)
(14.0-15.4)
(15.8-17.4)
(17.2-19.0)
(19.1-21.0) JL
(20.4-22.5)
(21.7-24.0)
(22.9-25.5)
(24.5-27.4)
(25.7-28.8)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a
given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=34.9917&Ion=-80.7722&data=depth&units=english&series=pds 1/4

9/12/2019 Precipitation Frequency Data Server
Pas -based depth -duration -frequency (DDF) curves
Latitude: 34.9917', Longitude:-80.7722'
IN
25
e
r 20
a
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L L
t L
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.................. J........ ....._.._.._l-__....__-._..__.__.._.. ...................................... ....._.. _....
q i TI I I I I I I I
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 Created {GMTY Thu Sep 12 12:45:57 2019
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
ini erva I
f years}
— 1
2
— 5
10
25
50
100
200
500
1000
Duration
— 5-min —
2-day
— 10-min —
3-day
15-min —
4-day
— 30-min —
7-day
— 60-min —
10-aay
— 2-hr —
20-day
— "r --
30-day
-� $fir —
45-day
— 12-hr —
60-day
— 24-hr
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.htmI?Iat=34.9917&Ion=-80.7722&data=depth&units=english&series=pds 2/4

9/12/2019
Precipitation Frequency Data Servei
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https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=34.9917&Ion=-80.7722&data=depth&units=english&series=pds 3/4

9/12/2019
Precipitation Frequency Data Server
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
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9/12/2019
Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Waxhaw, North Carolina, USA* '"
Latitude: 34.9917*, Longitude:-80.7722*
Elevation: 661.12 ft**
'source: ESRI Maps
** source: USGS C
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, I Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average
recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
5.00
5.90
6.85
7.55
8.35
8.90
9.41
9.85
10.4
10.7
5-min
(4.61-5.44)
(5.44-6.43)
(6.30-7.46)
(6.92-8.20)
(7.62-9.05)
(8.09-9.65)
(8.50-10.2)
(8.87-10.7)
(9.24-11.3)
(9.49-11.7)
4.00
4.72
5.49
6.04
6.65
7.09
7.47
7.81
8.20
8.45
10-min
(3.68-4.34)
(4.34-5.14)
(5.0-5.98)
(5.53-6.55)
(6.07-7.21)
(6.44-7.68)
(6.76-8.09)
(7.03-8.47)
(7.31-8.90)
(7.48-9.20)
3.33
3.96
4.63
5.09
5.62
5.98
6.30
6.57
6.88
7.07
15-min
(3.07-3.62)
(3.64-4.31)
(4.25-5.04)
(4.67-5.53)
(5.13-6.09)
(5.44-6.48)
(5.69-6.82)
(5.91-7.12)
(6.13-7.47)
(6.26-7.70)
2.28
2.73
3.29
3.69
4.16
4.50
4.82
5.12
5.48
5.73
30-min
(2.10-2.48)
(2.52-2.98)
(3.02-3.58)
(3.38-4.00)
(3.80-4.51)
(4.09-4.88)
(4.36-5.22)
(4.60-5.54)
(4.88-5.95)
(5.07-6.23)
1.42
1.72
2.11
2.40
2.77
3.05
3.32
3.59
3.93
4.18
60-min
(1.31-1.55)
(1.58-1.87)
(1.94-2.30)
(2.20-2.61)
(2.53-3.00)
(2.77-3.31)
(3.00-3.60)
(3.23-3.89)
(3.50-4.26)
(3.70-4.55)
0.824
0.996
1.23
1.42
1.65
1.83
2.01
2.19
2.43
2.61
2-hr
(0.754-0.900)
(0.912-1.09)
(1.13-1.35)
1 (1.29-1.55)
1 (1.50-1.80)
1 (1.65-1.99) 11
(1.81-2.19) 11
(1.95-2.39)
(2.14-2.65)
(2.28-2.85)
0.583
0.703
0.876
1.01
1.19
1.34
1.49
1.64
1.84
2.01
3-hr
(0.533-0.641)
(0.643-0.773)
(0.800-0.963)
(0.920-1.11)
1 (1.08-1.31)
1 (1.21-1.46) 11
(1.33-1.62) 11
(1.45-1.79)
1 (1.61-2.01)
1 (1.74-2.19)
0.351
0.423
0.528
0.611
0.723
0.814
0.906
1.00
1.14
1.24
6-hr
(0.322-0.385)
(0.388-0.465)
(0.483-0.579)
(0.557-0.668)
(0.656-0.789)
(0.733-0.886)
(0.811-0.986)
(0.888-1.09)
(0.992-1.23)
( 1.07-1.35)
0.206
0.249
0.312
0.362
0.433
0.490
0.549
0.612
0.699
0.771
12-hr
(0.189-0.226)
(0.229-0.274)
(0.286-0.342)
(0.331-0.397)
(0.392-0.472)
(0.440-0.534)
(0.489-0.597)
(0.539-0.665)
(0.606-0.760)
(0.659-0.838)
0.122
0.147
0.185
0.215
0.257
0.290
0.325
0.361
0.411
0.452
24-hr
(0.113-0.132)
(0.137-0.160)
(0.171-0.201)
(0.199-0.233)
(0.236-0.278)
(0.266-0.314)
(0.297-0.351)
(0.328-0.391)
(0.372-0.446)
(0.406-0.491)
0.072
0.087
0.108
0.125
0.149
0.167
0.187
0.207
0.235
0.258
2iiay
(0.067-0.078)
(0.080-0.094)
(0.100-0.117)
(0.115-0.136)
(0.137-0.161)
(0.153-0.181)
(0.171-0.203)
(0.189-0.225)
(0.213-0.256)
(0.232-0.282)
0.051
0.061
0.076
0.088
0.104
0.117
0.130
0.144
0.164
0.179
3iiay
(0.047-0.055)
(0.057-0.066)
(0.070-0.082)
(0.081-0.095)
(0.096-0.112)
(0.107-0.126)
(0.119-0.141)
(0.131-0.156)
(0.148-0.178)
(0.162-0.195)
0.040
0.048
0.060
0.069
0.081
0.091
0.102
0.113
0.128
0.140
aiiay
(0.038-0.044)
(0.045-0.052)
(0.055-0.065)
(0.064-0.074)
(0.075-0.088)
(0.084-0.099)
(0.093-0.110)
(0.103-0.122)
(0.116-0.138)
(0.127-0.152)
7iiay
0.025-0 029
0. 30-0 034
0. 36-0 042
0.041- 048
0.048-0 056
0.054-0 063
0. 60-0 069
0. 66-0.077
0.074-0.087
0. 80-0 095
0.021
0.025
0.031
0.035
0.040
0.045
0.049
0.054
0.060
0.065
10-day
(0.020-0.023)
(0.024-0.027)
(0.029-0.033)
(0.032-0.037)
(0.037-0.043)
(0.041-0.048)
(0.045-0.053)
(0.050-0.057)
(0.055-0.064)
(0.059-0.070)
0.014
0.017
0.020
0.022
0.026
0.028
0.031
0.033
0.037
0.040
20-day
(0.013-0.015)
(0.016-0.018)
(0.019-0.021)
(0.021-0.024)
(0.024-0.027)
(0.026-0.030)
(0.029-0.033)
(0.031-0.036)
(0.034-0.040)
(0.037-0.043)
0.012
0.014
0.016
0.018
0.020
0.022
0.024
0.025
0.028
0.029
30-day
(0.011-0.012)
(0.013-0.015)
(0.015-0.017)
(0.017-0.019)
(0.019-0.021)
(0.020-0.023)
(0.022-0.025)
(0.024-0.027)
(0.026-0.030)
(0.027-0.031)
45-day
0. 09-0 010
0.011-0.012
0.01 -0 014
0.014- 015
0.015-0 017
0.016-0 018
0.017--0 020
0.019-0 021
0.020-0.023
0.021--0 024
0.009
0.010
0.012
0.013
0.014
0.015
0.016
0.017
0.018
0.019
60-day
(0.008-0.009)
(0.010-0.011)
(0.011-0.012)
(0.012-0.013)
(0.013-0.015)
(0.014-0.016)
(0.015-0.017)
(0.016-0.018)
(0.017-0.019)
(0.018-0.020)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a
given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=34.9917&Ion=-80.7722&data=intensity&units=english&series=pds 1/4

9/12/2019
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Precipitation Frequency Data Server
PDS-based intensity -duration -frequency (IDF) curves
Latitude: 34.9917', Longitude:-80.7722'
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1 2 5 10 25 50 IN200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 Created {GMTY Thu Sep 12 12:46.29 2019
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
ini erva I
{years}
— 1
2
— 5
10
25
50
100
200
500
1000
Duration
— 5-min —
2-day
— 10-min —
3-day
15-min —
4-day
— 30-min —
7-day
— 60-ivn —
10-aay
— 2-hr —
20-day
— "r --
30-day
-� $fir —
45-day
— 12-hr —
60-day
— 24-hr
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=34.9917&Ion=-80.7722&data=intensity&units=english&series=pds 2/4

9/12/2019
Precipitation Frequency Data Servei
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https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=34.9917&Ion=-80.7722&data=intensity&units=english&series=pds 3/4

9/12/2019
Precipitation Frequency Data Server
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
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is)
Pre
Z5P
Sand Filter
Post
Subcat Reach on Link

Sand Filter - Oldcastle Stormcapture
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 2
Area Listing (all nodes)
Area CN Description
(acres) (su bcatch me nt-n u mbe rs)
0.220
77
(is)
1.010
91
(2S)
1.230
88
TOTAL AREA

Sand Filter - Oldcastle Stormcapture
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 3
Soil Listing (all nodes)
Area Soil Subcatchment
(acres) Group Numbers
0.000
HSG A
0.000
HSG B
0.000
HSG C
0.000
HSG D
1.230
Other 1 S, 2S
1.230
TOTAL AREA

Sand Filter - Oldcastle Stormcapture
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 4
Ground Covers (all nodes)
HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment
(acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers
0.000 0.000 0.000 0.000 1.230 1.230 1 S, 2S
0.000 0.000 0.000 0.000 1.230 1.230 TOTAL
AREA

Sand Filter - Oldcastle Stormcapture
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 5
Pipe Listing (all nodes)
Line# Node In -Invert Out -Invert Length Slope n Diam/Width Height Inside -Fill
Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches)
1 5P 651.00 650.40 20.1 0.0299 0.013 18.0 0.0 0.0

Sand Filter - Oldcastle Stormcapture Type 11 24-hr 2-yr Rainfall=3.54"
Prepared by {enter your company name here} Printed 10/22/2019
HvdroCAD® 10.00-24 s/n 10182 © 2018 HvdroCAD Software Solutions LLC Paae 6
Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment1S: Pre Runoff Area=0.220 ac 0.00% Impervious Runoff Depth=1.46"
Tc=18.0 min CN=77 Runoff=0.37 cfs 0.027 of
Subcatchment2S: Post Runoff Area=1.010 ac 0.00% Impervious Runoff Depth=2.58"
Tc=5.0 min CN=91 Runoff=4.46 cfs 0.217 of
Pond 5P: Sand Filter Peak Elev=656.41' Storage=0.051 of Inflow=4.46 cfs 0.217 of
Outflow=6.18 cfs 0.217 of
Total Runoff Area = 1.230 ac Runoff Volume = 0.244 of Average Runoff Depth = 2.38"
100.00% Pervious = 1.230 ac 0.00% Impervious = 0.000 ac

Sand Filter - Oldcastle Stormcapture Type 11 24-hr 2-yr Rainfall=3.54"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment 1S: Pre
Runoff = 0.37 cfs @ 12.11 hrs, Volume= 0.027 af, Depth= 1.46"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-yr Rainfall=3.54"
Area (ac) CN Description
0.220 77
0.220 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.0 Direct Entry,
Subcatchment 1S: Pre
Hydrograph
-----�-- J -- 1 -- L-----�-- J -- 1--+-- L-----�-- J -- 1 -- L--------�-- 1--+-- L--I--
0.4 _a ------- -- --+--------- -- ------------ --+-- ----
7 cfs -
0.38 0.3
---- - -- -- -- ----+--+-- -- --r-- yf-- +�1+2_ �'r-
0.36 --�
- r-- r-- r-- r-- I - - r-- r-- r----- r-r--r--r--r--r --� ���p� r -
0.34 --r --r-- r--r--rrrr - -r - -
r i--r--r r--- M-
0.32 - - - -
-- - -- -- -- ----12-yr r-Rainfa�tl_�3.a4�--
0.3 ----
- --------------- ----------,--R-Un6ff'A-teA=E-.22aat-
0.28 ---- - -- --------------+---------- -- ------------ --+-- ----
0.26 ---- - -- --------- -- --+-- -----R�ngff �V����n1e=0:$27-1
w 0.24 --+--+--+--+--+--+-+--+--+--+--+-+--+--+p--+Inn-�y+� +-+--*+--+--y+�-�-+-
w i Runoff IiQepth:0.4 i„-
0.22 --�---r--r--r--r--�--r--r--+--r--�---�--r--
0 0.2 --r- r--r--r--r----r--r--t--r--r----r--r--r--r-
LL 0.18 --r - r-- r--r --r----r-- r-- r --r --r - -- r-- r--r --r T=1S.II-r ih=
0.16 j - - -- -- --i CN=-77-
-------------------------------------------
0.14 --�'-----------'-
---------------------
0.12 --'----1--L--1---1--J--1--1-------'-- --1--L----------1--+--L--'--
0.1 --+- +--+--+--+--+-+--+--+--+--+--i--+--+--+--+--+--i--+--+--+--+-
0.08 --�--+--+--+------+--+--+--+-------+--+--+---------+--+--+--�--
0.06 --r- r--r--r--r----r--r--t--r--r----r--r--r--r-------r--t--r--r-
0.04--r---r--r--r----r--r--T--r--r-r--r--r--r--r----r--r--r--r--r-
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

Sand Filter - Oldcastle Stormcapture Type 11 24-hr 2-yr Rainfall=3.54"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 8
Summary for Subcatchment 2S: Post
[49] Hint: Tc<2dt may require smaller dt
Runoff = 4.46 cfs @ 11.95 hrs, Volume= 0.217 af, Depth= 2.58"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 2-yr Rainfall=3.54"
Area (ac) CN Description
1.010 91
1.010 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post
Hydrograph
� � � � � � � � � � � � � � � � � � � � � � � ■Runoff
4.46 cfs
-- - -- -- - - -- - - - -- I'Ty;p� II',2-h'r-
4 2 r r R'ainfallT3.'541�
RWnbffl Awea=1.010 at.
3
--�---�--�--1--1--�---�---�--J--1--1--'R�nOff1�-QC�me-b.-�1�-af-
�i =
Runoff Dept&1�2.�'1581"
° TS,Q �t�i is -
LL
2 CAN=91
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Sand Filter - Oldcastle Stormcapture Type 11 24-hr 2-yr Rainfall=3.54"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 9
Summary for Pond 5P: Sand Filter
[44] Hint: Outlet device #2 is below defined storage
[92] Warning: Device #3 is above defined storage
[93] Warning: Storage range exceeded by 0.41'
[95] Warning: Outlet Device #2 rise exceeded
[88] Warning: Qout>Qin may require smaller dt or Finer Routing
[85] Warning: Oscillations may require smaller dt or Finer Routing (severity=84)
Inflow Area = 1.010 ac, 0.00% Impervious, Inflow Depth = 2.58" for 2-yr event
Inflow = 4.46 cfs @ 11.95 hrs, Volume= 0.217 of
Outflow = 6.18 cfs @ 11.99 hrs, Volume= 0.217 af, Atten= 0%, Lag= 2.5 min
Primary = 6.18 cfs @ 11.99 hrs, Volume= 0.217 of
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 656.41' @ 12.00 hrs Surf.Area= 0.000 ac Storage= 0.051 of
Plug -Flow detention time= 361.5 min calculated for 0.217 of (100% of inflow)
Center -of -Mass det. time= 361.4 min ( 1,156.1 - 794.7 )
Volume Invert Avail.Storage Storage Description
#1 652.50' 0.051 of Custom Stage Data Listed below
Elevation Cum.Store
(feet)
(acre-feet)
652.50
0.000
653.00
0.007
654.00
0.022
655.00
0.036
656.00
0.051
Device Routing Invert Outlet Devices
#1 Primary 651.00' 18.0" Round RCP -Round 18"
L= 20.1' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 651.00' / 650.40' S= 0.0299 '/' Cc= 0.900
n= 0.013, Flow Area= 1.77 sf
#2 Device 1 651.00' Special & User -Defined
Head (feet) 0.00 0.50 1.50 2.50 3.50 4.50
Disch. (cfs) 0.000 0.009 0.014 0.019 0.024 0.028
#3 Device 1 656.00' Custom Weir/Orifice, Cv= 2.62 (C= 3.28)
Head (feet) 0.00 1.00
Width (feet) 7.00 7.00
Primary OutFlow Max=5.64 cfs @ 11.99 hrs HW=656.39' (Free Discharge)
L1=RCP_Round 18" (Passes 5.64 cfs of 18.33 cfs potential flow)
�__2=Special & User -Defined (Custom Controls 0.03 cfs)
3=Custom Weir/Orifice (Weir Controls 5.62 cfs @ 2.05 fps)

Sand Filter - Oldcastle Stormcapture Type 11 24-hr 2-yr Rainfall=3.54"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 10
Pond 5P: Sand Filter
Hydrograph
■ Inflow
6.18 Cfs [I Primary
Inflow ',Area=1.01'', 0 '',ar,
6-
1 - - ---POa;lk-lle�=05�41'--
5 4 cfs StbrageTO 051 of
---------------------
w 4
U
-- -t--_----t--t--t----t--t--t----t--t--t----t--t--t----t--t--
30
a 3 1 1
2
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Sand Filter - Oldcastle Stormcapture Type/1 24-hr 10-yr Rainfall=5.16"
Prepared by {enter your company name here} Printed 10/22/2019
HvdroCAD® 10.00-24 s/n 10182 © 2018 HvdroCAD Software Solutions LLC Paae 11
Time span=0.00-120.00 hrs, dt=0.05 hrs, 2401 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment1S: Pre Runoff Area=0.220 ac 0.00% Impervious Runoff Depth=2.76"
Tc=18.0 min CN=77 Runoff=0.71 cfs 0.051 of
Subcatchment2S: Post Runoff Area=1.010 ac 0.00% Impervious Runoff Depth=4.14"
Tc=5.0 min CN=91 Runoff=6.94 cfs 0.348 of
Pond 5P: Sand Filter Peak Elev=656.48' Storage=0.051 of Inflow=6.94 cfs 0.348 of
Outflow=7.71 cfs 0.348 of
Total Runoff Area = 1.230 ac Runoff Volume = 0.399 of Average Runoff Depth = 3.89"
100.00% Pervious = 1.230 ac 0.00% Impervious = 0.000 ac

Sand Filter - Oldcastle Stormcapture Type/1 24-hr 10-yr Rainfall=5.16"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 12
Summary for Subcatchment 1S: Pre
Runoff = 0.71 cfs @ 12.11 hrs, Volume= 0.051 af, Depth= 2.76"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-yr Rainfall=5.16"
Area (ac) CN Description
0.220 77
0.220 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
18.0 Direct Entry,
Subcatchment 1S: Pre
Hydrograph
---------+--+-------+--+--+--+-------+--+--+----------+--+--+----- ■Runoff
0.750.71 cfs
0.7 X p� �� 24
-hr- -
/
-- ---rt--r----rt--t--r-- --�--rt - -- t
0.65--II-- - -- -- -- --ill---III-- -- --ill---ill-- ----1fl-ryr-RairtfaiFF�frAG"--
0.6 I I I I I 1
Rind Ate&Q.22IG at--
0.55 --'---�--L--L--L--1--J--1--L--�--'---'--�--L--L--L--1---1--1--L--�--'---
w 0.45
-- - -- --------- -- -- ----------Runoff�©ePth;2.7,67--
0.35 ITd=18.0 %nih
------+-----------+--+-----------+-------I---I--+--+----I--j--
0.3 C 7'F
0.25
--I-- r--r--r-------r--r--r--r-------r--r--r----------r--r--r--I---
0.2
---- ------------------------------------------------------------
0.15
- -� - 1 - - 7 - - r 1 - - 7 - - T - - r 1 - - 7 - - r 7 - - T - - r
0.1
--'-- 0.057-3
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Sand Filter - Oldcastle Stormcapture Type/1 24-hr 10-yr Rainfall=5.16"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 13
Summary for Subcatchment 2S: Post
[49] Hint: Tc<2dt may require smaller dt
Runoff = 6.94 cfs @ 11.95 hrs, Volume= 0.348 af, Depth= 4.14"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-yr Rainfall=5.16"
Area (ac) CN Description
1.010 91
1.010 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post
Hydrograph
I I I I I I I I I I I I I I I I I I I I I I I ■Runoff
6.94 cfs - -- --------------'I-- - -- --- ---------I- -- --
Type 11'124-h'Ir
-I-- -- -- --II--------I-- -- -- ---1�ryr-Faifa►11T5:'11�"-
6 I I I I I I I I I I I I I I I I I
Runbff Awes=1.010 at
5 RL#nOff'IVQILjl m'e=',0.$4$ of
V 4 Runoff-De-0=4-11�1
3 I I I I
LL I I I I I I I I I I I
TcT5.0 tnih
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3 CAN=91
2
---- ----;--;----------------;--;-----I-----------;----------------
1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Sand Filter - Oldcastle Stormcapture Type/1 24-hr 10-yr Rainfall=5.16"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 14
Summary for Pond 5P: Sand Filter
[44] Hint: Outlet device #2 is below defined storage
[92] Warning: Device #3 is above defined storage
[93] Warning: Storage range exceeded by 0.48'
[95] Warning: Outlet Device #2 rise exceeded
[88] Warning: Qout>Qin may require smaller dt or Finer Routing
[85] Warning: Oscillations may require smaller dt or Finer Routing (severity=120)
Inflow Area = 1.010 ac, 0.00% Impervious, Inflow Depth = 4.14" for 10-yr event
Inflow = 6.94 cfs @ 11.95 hrs, Volume= 0.348 of
Outflow = 7.71 cfs @ 11.95 hrs, Volume= 0.348 af, Atten= 0%, Lag= 0.0 min
Primary = 7.71 cfs @ 11.95 hrs, Volume= 0.348 of
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 656.48' @ 11.95 hrs Surf.Area= 0.000 ac Storage= 0.051 of
Plug -Flow detention time= 234.0 min calculated for 0.348 of (100% of inflow)
Center -of -Mass det. time= 234.7 min ( 1,016.2 - 781.6 )
Volume Invert Avail.Storage Storage Description
#1 652.50' 0.051 of Custom Stage Data Listed below
Elevation Cum.Store
(feet)
(acre-feet)
652.50
0.000
653.00
0.007
654.00
0.022
655.00
0.036
656.00
0.051
Device Routing Invert Outlet Devices
#1 Primary 651.00' 18.0" Round RCP -Round 18"
L= 20.1' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 651.00' / 650.40' S= 0.0299 '/' Cc= 0.900
n= 0.013, Flow Area= 1.77 sf
#2 Device 1 651.00' Special & User -Defined
Head (feet) 0.00 0.50 1.50 2.50 3.50 4.50
Disch. (cfs) 0.000 0.009 0.014 0.019 0.024 0.028
#3 Device 1 656.00' Custom Weir/Orifice, Cv= 2.62 (C= 3.28)
Head (feet) 0.00 1.00
Width (feet) 7.00 7.00
Primary OutFlow Max=7.66 cfs @ 11.95 hrs HW=656.48' (Free Discharge)
L1=RCP_Round 18" (Passes 7.66 cfs of 18.51 cfs potential flow)
�__2=Special & User -Defined (Custom Controls 0.03 cfs)
3=Custom Weir/Orifice (Weir Controls 7.64 cfs @ 2.27 fps)

Sand Filter - Oldcastle Stormcapture Type/1 24-hr 10-yr Rainfall=5.16"
Prepared by {enter your company name here} Printed 10/22/2019
HydroCAD® 10.00-24 s/n 10182 © 2018 HydroCAD Software Solutions LLC Page 15
Pond 5P: Sand Filter
Hydrograph
------------------------- ---------------------------- -- ❑ Inflow
❑ Primary
' 7.71 cfs lo �
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7 'Pa'khevr=05j6.48'--
6 �tbreTO 051 of
--
w 5
w -- -r--r--r-r--r--r--r-r--r--r--r-r--r--r--r-r--r--r--r-r--r--
U
0 4 I II II II II II II II II II II II II II II II II II II II II
LL--------------------------------�_------_�_---�--
3
2
- -T T--T--T-----1 T - -r-- T--T--T--i----T--F--I--T--
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)