SW3220803_Stormwater Report_20230425

STORMWATER MANAGEMENT REPORT
FOR:
CRESSWIND WESLEY CHAPEL - PHASE 04
WESLEY CHAPEL, NC
PREPARED FOR:
KH WESLEY CHAPEL, LLC
J -#2 7842.0004
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Prepared by:
THOMAS & HUTTON

STORMWATER MANAGEMENT REPORT
Cresswind Wesley Chapel - Phase 04
Project: Cresswind Wesley Chapel - Phase 04
T&H Job Number: J-27842.0004
Location: Potter Road
Wesley Chapel, NC 28173
Date Prepared: May 25, 2022
Owner: KH Wesley Chapel, LLC
Owner Address: 8913 Silver Springs Court Drive
Charlotte, NC 28215
Engineer: Thomas & Hutton
Engineer Address: 1020 Euclid Avenue
Charlotte, NC 28203
Phone: [phone]
H THOMAS & HUTTON
Page 1

TABLE OF CONTENTS
Section 1 -Summary of Results.......................................................................................................Page 3
Section 2- Project Narrative...........................................................................................................Page 4
Section3- Purpose...........................................................................................................................Page 4
Section 4- Regulatory Summary ....................................................................................................Page 5
Section5- Methodology.................................................................................................................Page 5
Section6- Hydrology.......................................................................................................................Page 6
Section 7- Runoff Calculations ......................................................................................................Page 6
Section 8- Existing Conditions ........................................................................................................Page 8
Section 9- Post Development Conditions.....................................................................................Page 8
APPENDICES
ProjectMapping......................................................................................................................Appendix A
Aerial Location Map.......................................................................................................... Exhibit A
FEMAMap ...........................................................................................................................Exhibit B
WetlandsMap.................................................................................................................... Exhibit D
SoilsMap..............................................................................................................................Exhibit E
Pre Development Drainage Map...........................................................................................Appendix B
Pre Development Conditions Drainage Calculations.........................................................Appendix C
Post Development Drainage Map ........................................................................................Appendix D
Post Development Conditions Drainage Calculations........................................................Appendix E
Water Quality Calculations......................................................................................................Appendix F
H THOMAS & HUTTON
Page 2

SECTION 1 - SUMMARY OF RESULTS
Table 1 - Pre Development Runoff Rates
TABLE 1
Summar of Results- Existing Conditions
Storm Event Outfall 01
(cfs)
2-year 69
10-Year 154
25-Year 201
50-Year 244
Table 2- Post Development Runoff Rates
TABLE 1
Summary of Results- Proposed Conditions
Storm Event Outfall 01
cfs
2-year 30
10-Year 98
25-Year 151
50-Year 195
H THOMAS HUTTON
Page 3

SECTION 2 - PROJECT NARRATIVE
Cresswind is a residential subdivision within Wesley Chapel, North Carolina. Phase 4 consists of
approximately 147 single family detached units.The site is located in Union County along Potter
Road, north of Newtown Road and south of Weddington Road. It should be noted that a portion
of Phase 5 lots and impervious area is included in the post development calculations for the
proposed pond.
The majority of the site is currently wooded with an understory of brush. Pre-development run-
off is discharged into an existing wetland system and FEMA Floodplain. The pre-development
drainage basins have been delineated and are illustrated on the Pre-Development Drainage
Exhibit found at the end of this report.
For the purpose of this report, we will compare the predevelopment runoff rates to the post
development runoff rates as shown in the summary at the beginning of this report. The pre-
development basin will be routed through one wet detention pond during post development
conditions and outfall into the existing wetlands and floodplain.
The post-development sub-basins were delineated and are illustrated on the Post-Development
Drainage Exhibit found at the end of this report. All design information for ponds and associated
drainage pipes and structures can be found in the appendices of this report.
The soils on this site consist of type B, C, D and B/D hydrologic soil groups which are shown on the
attached NRCS soils map within Appendix A.
SECTION 3 - PURPOSE
The purposes of this report are:
1. To delineate all pre-development basins that are within this project and determine
which drainage basins will be affected by the proposed development.
2. To develop a stormwater model that will:
a. Be in compliance with the NCDEQ stormwater regulations.
b. Simulate the pre- and post-development conditions for the project.
c. Predict water elevations for all proposed ponds.
d. Demonstrate that all culverts are of adequate size for drainage under post-
development conditions.
e. Provide design flows (under future build out conditions) for the major drainage
structures that can be used to properly size improvements, if needed.
3. To document that the stormwater management measures and equipment installed
on site will be adequate for all existing and proposed development on the site.
Two drainage models are included in this report;
• Pre-Development: examines the drainage basin prior to any development within the site.
• Post-Development: examines the drainage basin after site improvements have been
installed. The model may need to be revised and updated for each phase that is
permitted.
H THOMAS & HUTTON
Page 4

SECTION 4 - REGULATORY SUMMARY
NCDEQ-Stormwater
The North Carolina Department of Environmental Quality (NCDEQ) is responsible for
administering the storm water management program.
Development or re-development activities are required to apply for and receive a stormwater
permit from NCDEQ. These permits address water quality and quantity.
NCDEQ regulations require that peak post-development discharge rates from the basin shall be
at or below pre-development rates for the 10 and 25-year storms events. The regulations also
specify the 1-inch volume drawdown shall be released over a time of 48 to 120 hours to minimize
hydrologic impacts to the receiving channel. See attached Exhibit E for post-development peak
flow control calculations, and Exhibit F for water quality calculations.
The stormwater treatment shall be designed to achieve average annual 857o Total Suspended
Solids (TSS) removal and must apply to the volume of post-development runoff resulting from the
one-inch rainfall. See attached Exhibit E for post-development peak flow control calculations,
and Exhibit F for water quality and channel protection calculations.
SECTION 5 - METHODOLOGY
The pre- and post-development conditions of the site were analyzed using the Storm and
Sanitary Analysis (SSA) program developed by Autodesk. The program is used to model rainfall
and stormwater runoff and to perform hydraulic routing through the storm drainage system
(including existing and proposed storage/detention features such as wetlands, ponds, and
lakes).
SSA is an advanced, powerful, and comprehensive modeling package for analyzing and
designing drainage systems, stormwater sewers, and sanitary sewers. The software can
simultaneously model complex hydrology, hydraulics, and water quality. The SSA program is
built on the highly tested and widely utilized SWMM methodologies. For this application of the
SSA program, the hydrology was simulated using the NRCS (SCS) TR-55 methodology. The
hydraulics was simulated utilizing hydrodynamic routing. Hydrodynamic routing solves the
complete St. Venant equations throughout the drainage network and includes modeling of
backwater effects, flow reversal, surcharging, looped connections, pressure flow, tidal outfalls,
and interconnected ponds.
The SSA program graphical user interface (GUI) allows for the input of hydrologic data for each
drainage sub-basin. See the appendices for input variables including runoff curve number,
rainfall distribution pattern, hydrograph peaking factor, area of each drainage sub-basin, and
time of concentration. The SSA program generates runoff hydrographs for each sub-basin
based on these user-specified variables. Hydrographs are generated by SSA using the NRCS Unit
Hydrograph (TR-55) Method.
H THOMAS & HUTTON
Page 5

The model's hydraulic input data consists of a system of nodes and links. Nodes represent
locations where flows enter or exit the system, pipe or channel characteristics change, or where
stage/storage/time relationships are provided. Links represent traditional types of hydraulic
conveyance such as pipes, channels, control structures, weirs, etc. The sizes, inverts, lengths, and
Manning "n" values for all pipes connecting the ponds or lakes are input into the model. In
addition to pipe information, all pond, lake, and detention area stage-area information and the
respective control structure information is input into the model. The node and link conditions are
analyzed within the model for a given storm, and flow conditions are determined.
Hydrographs for each drainage area are merged within the SSA program, and the hydrologic
results are then combined with the hydraulic information to model the hydraulic interactions of
the entire drainage system. The results include pond area and discharge rates and stage/storage
information during the storm events.
The storm drainage infrastructure onsite was modelled using the Storm Sewers program developed
by Autodesk. This program utilizes the model rainfall and stormwater runoff through the storm
drainage infrastructure to provide hydraulic grade line calculations and profiles for analyzing the
proposed storm drain network.
SECTION 6 - HYDROLOGY
■ SCS TR-55 Method was used.
■ The rainfall distribution used for each storm event was obtained from rainfall data publicly
available for Union County, NC. The following design storms are used in the model
simulations:
- 2-year, 24-hour Design Storm = 3.50 inches
- 10-year, 24-hour Design Storm = 5.20 inches
- 25-year, 24-hour Design Storm = 6.10 inches
- 50-year, 24-hour Design Storm = 6.90 inches
- 100-year, 24-hour Design Storm = 7.50 inches
■ SCS Type II Statistical Rainfall Distribution was used. This distribution pattern is determined
by the Soil Conservation Service comparing regional rain-gage data.
■ Soils present on site consist of the following:
- Badin channery silty clay loam, 2 to 8 percent slopes (BdB2) - HSG C
- Chewacla silt loam, 0 to 2 percent slopes (ChA) - HSG B/D
- Goldstone-Badin complex (GsC), 8 to 15 percent slopes- HSG C
- Tarrus gravelly silty clay loam, 2 to 8 percent slopes (TbB2) - HSG B
SECTION 7 - RUNOFF CALCULATIONS
Peak flow rates for the watersheds were calculated by the SSA Program for each design storm.The
pre- and post-development drainage basins are shown in appendicies that follow this report.
H THOMAS & HUTTON
Page 6

Curve Numbers
Curve numbers were generated according to procedures set forth in SCS Technical
Release 55. The composite curve numbers for each drainage basin were calculated
using soils information from the Soil Survey of Union County, NC provided by The United
States Department of Agriculture Soil Conservation Service. Curve numbers were
weighted based on the land use and soil group within each basin.
Time of Concentration
Times of concentration were calculated according to procedures set forth in SCS
technical Release (TR) 55. The travel times (Tt) for overland flow, shallow concentrated
flow, and channel flow are added together for the drainage basin to get the time of
concentration Tc.
Basin information for the area of interest was collected for use in the SSA models. Basins
were delineated using surveyed topographic information. Basins were drawn and the
longest flow paths were found. The times of concentration were calculated based on
the NRCS, three part travel time method documented in TR-55. The three equations used
are summarized below:
Sheet Flow: (hr) Symbol Dimension Units
_ 0.007(nL)0•$ n Mannin 's n --
�� - P 0.05 X SOA L Length of flow ft
2 2 yr event
P2 rainfall in
S Slope ft/ft
Shallow Concentrated Flow: (hr) Symbol Dimension Units
L L Length of flow ft
tz 3600 X V V* Velocity ft/s
*Based on TR-55 velocity-slope relationship
Channel Flow: (hr) Symbol Dimension Units
L L Length of flow ft
_
t3 3600 X V V* Velocity ftA
*Assumed to be 2 ft/s
Time of Concentration: (hr)
Appendices C and E with time of concentration information are attached.
Mr.
THOMAS & HUTTON
Page 7

SECTION 8 - EXISTING CONDITIONS
The total acreage of the drainage basins analyzed in the stormwater calculations is
approximately 40 acres. The existing conditions described in this narrative will refer to the pre-
development condition of the site. The pre-development conditions for the site consists
predominantly of woods with an understory of brush.
Stormwater runoff on the site was delineated according to the existing drainage patterns found
at the site and upon the field topographic survey completed within the site. The watershed
delineation was conducted to provide a comparison for pre-development and post-
development flows. Outfall "01" discharges into an existing wetland (See Pre Development
Drainage Map-Appendix B).
SECTION 9 - POST- DEVELOPMENT CONDITIONS
The post-development drainage basins are shown on the Post-Development conditions
watershed map located in Appendix D of this report. The total post-development watershed
area analyzed for this project is approximately 50 acres. This site maintains all pre-development
discharge points in the post-development condition. Post-development peak flows are less than
pre-development conditions for the 2-yr, 10-yr, and 25-yr storm events. See Appendices B
through H for pre- and post-development SSA model input and results. See Summary of pre-
development versus post-development results at the beginning of report.
After development, the site will consist of approximately 144 single family lots in Phase 4 and
associated public roads, private driveways, and stormwater management features such as
drainage swales and stormwater detention ponds. It should be noted that a portion of Phase 4
lots and impervious area is included in the post development calculations for the proposed
pond. Stormwater runoff from site will be conveyed to a proposed wet detention pond. The
detention pond will meet NCDEQ pre- and post-development flows and meet freeboard
requirements for the ten (10) year, twenty-five (25) year, and fifty (50) year storm events.
The proposed detention ponds were designed to meet criteria found in the NCDEQ BMP Design
Manual. Additionally, the required freeboard has been provided beneath the emergency
spillways and the pond embankments for the (50) year storm event. The following tables illustrate
the maximum water surface elevation for the two (2) year, ten (10) year, twenty-five (25) year, and
fifty (50) year storm events both ponds.
H THOMAS & HUTTON
Page 8

Table 3-Wet Detention Pond 05
Bottom of Pond = 570.00
Crest of Emergency Spillway = 578.50
Top of Embankment= 580.00
Wet Detention Pond 04
Max Elevation
Storm Event
(f0
10-Year 578.86
25-Year 579.16
50-Year 579.36
100-Year 579.48
H THOMAS & HUTTON
Page 9

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX A
PROJECT MAPPING
27842.0004
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Hydrologic Soil Group—Union County, North Carolina
(Soils) M
M
529600 529700 529800 529900 530000 530100 530200 530300 530400 530500 530MO 530700 530800 5309M 531000
34o 59'20"N 1 1 ,I. I I I _ 1 34o 59'20"N
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Soil MaN may not 1. valiel at this scale.
340 58'49"N 340 58'49"N
529700 5298M 529900 530000 530100 530200 530300 530400 530500 530600 530700 530800 5309M 531000
in
Map Scale:1:6,650 if printed on A landscape(11"x 8.5")sheet.
Meters
$ N 0 50 100 200 300 $
Feet
0 300 600 1200 1�0
Map projection:Web Mercator Conermordinates:WGS84 Edge tics:UTM Zone 17N WGS84
usoA Natural Resources Web Soil Survey 12/3/2021
Conservation Service National Cooperative Soil Survey Pagel of 4

Hydrologic Soil Group—Union County, North Carolina
(Soils)
MAP LEGEND MAP INFORMATION
Area of Interest(A01) ❑ C The soil surveys that comprise your AOI were mapped at
0 Area of Interest(AOI) 0 C/D 1:24,000.
Soils D Warning:Soil Map may not be valid at this scale.
Soil Rating Polygons �
A p Not rated or not available Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
A/D Water Features line placement.The maps do not show the small areas of
Streams and Canals contrasting soils that could have been shown at a more detailed
0 B
scale.
Transportation
Q B/D Rails Please rely on the bar scale on each map sheet for map
Q C measurements.
­0 Interstate Highways
0 C/D US Routes Source of Map: Natural Resources Conservation Service
D Web Soil Survey URL:
Major Roads Coordinate System: Web Mercator(EPSG:3857)
LJ Not rated or not available Local Roads
Maps from the Web Soil Survey are based on the Web Mercator
Soil Rating Lines Background projection,which preserves direction and shape but distorts
* 0 q distance and area.A projection that preserves area,such as the
Aerial Photography Albers equal-area conic projection,should be used if more
* 0 A/D accurate calculations of distance or area are required.
r*/ B This product is generated from the USDA-NRCS certified data as
B/D of the version date(s)listed below.
0 C Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 21, Sep 15,2021
r 0 C/D
Soil map units are labeled(as space allows)for map scales
0 D 1:50,000 or larger.
A 0 Not rated or not available Date(s)aerial images were photographed: Jul 18,2011—Oct 30,
Soil Rating Points 2018
0 A The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
0 A/D imagery displayed on these maps.As a result,some minor
0 B shifting of map unit boundaries may be evident.
0 B/D
uson Natural Resources Web Soil Survey 12/3/2021
Conservation Service National Cooperative Soil Survey Page 2 of 4

Hydrologic Soil Group—Union County, North Carolina Soils
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
BdB2 Badin channery silty C 16.4 16.0%
clay loam,2 to 8
percent slopes,
moderately eroded
ChA Chewacla silt loam,0 to B/D 11.6 11.3%
2 percent slopes,
frequently flooded
GsC Goldston-Badin D 5.4 5.3%
complex,8 to 15
percent slopes
TbB2 Tarrus gravelly silty clay B 69.1 67.4%
loam,2 to 8 percent
slopes,moderately
eroded
Totals for Area of Interest 102.6 100.0%
USDA Natural Resources Web Soil Survey 12/3/2021
Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group—Union County, North Carolina Soils
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
USDA Natural Resources Web Soil Survey 12/3/2021
Conservation Service National Cooperative Soil Survey Page 4 of 4

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX B
PRE-DEVELOPMENT DRAINAGE MAP
27842.0004
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o- - CN: 79 IJI %/ jig 565 /,�i/%/ / mil/ / / '\�✓ 7
L /� Tc: 37 MIN. 635 U /
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ARE 51.90 AC. ) / l ) /1/1l ? -
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Tc: 32 MIN.
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/ / \595 \\\�� 1I(l IIII 111 /IIII , 65Ur �✓ .
llllll% l 111 \ 1 1 \ \ ' � \
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AREA: 17.9 AC.
CN: 86 - a rl-_- / 60
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PREPARED FOR:
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KH WESLEY CHAPEL LLC
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OUTFACE
THOMAS
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H HUTTO N
J( k 1020 Euclid Avenue` 565' Charlotte, NC 28202 • 980.201.5505
I w vw.thomasandhutton.com
JOB NO: J-27842.0002 DATE: 2/16/2021
DRAWN: KSC SCALE: 1"= 180'
REVIEWED: MSK SHEET: N/A

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX C
PRE-DEVELOPMENT CONDITIONS
DRAINAGE CALCULATIONS
27842.0004
T
THOMAS & HUTTON

27842.0004
CRESSWIND WESLEY CHAPEL - PHASE 04
PRE-DEVELOPMENT BASINS MODEL
out
■
-0,

Pre-Development 002-Year Page 1
Project Description
File Name....................................................27842.0004-Pre dvelopment.SPF
Project Options
Flow Units--------------------------------------------------- CFS
Elevation Type Elevation
Hydrology Method. SCS TR-55
Time of Concentration(TOC)Method-------- SCS TR-55
Link Routing Method Hydrodynamic
Enable Overflow Ponding at Nodes------------ YES
Skip Steady State Analysis Time Periods--- NO
Analysis Options
Start Analysis On. Dec 03,2019 00:00:00
End Analysis On. Dec 04,2019 00:00:00
Start Reporting On. Dec 03,2019 00:00:00
Antecedent Dry Days 0 days
Runoff(Dry Weather)Time Step---------------- 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step--------------- 0 00:05:00 days hh:mm:ss
Reporting Time Step----------------------------------- 0 00:05:00 days hh:mm:ss
Routing Time Step-------------------------------------- 1 seconds
Number of Elements
Qty
Rain Gages 1
Subbasins 1
Nodes 1
Junctions 0
Outfalls 1
Flow Diversions 0
Inlets 0
Storage Nodes 0
Links 0
Channels 0
Pipes 0
Pumps 0
Orifices 0
Weirs 0
Outlets 0
Pollutants 0
Land Uses 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
1 Time Series TS-002 Intensity inches North Carolina Union 2 3.50 SCS Type II 247hr

Pre-Development 002-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 39.76 484.00 73.00 3.50 1.18 46.92 7228 0 00-05-00

Pre-Development 002-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft') (cfs) (ft) (ft) (ft)(days hh:mm) (ac-in) (min)
1 Out-01 Outfall 0.00 0.00 0.00

Pre-Development 002-Year Page 4
Subbasin Hydrology
Subbasin : Sub-01
Input Data
Area(ac)------------------------------------------------------------------------39-76
Peak Rate Factor-----------------------------------------------------------484-00
Weighted Curve Number-----------------------------------------------73-00
Rain Gage ID
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
39-76 73-00
Composite Area&Weighted CN 39-76 73-00
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0-007*((n*Lf)^0-8))/((P^0-5)*(Sf^0-4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf =Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf =Slope(ft/ft)
Shallow Concentrated Flow Equation:
V =16-1345*(Sf^0-5)(unpaved surface)
V =20-3282*(Sf^0-5)(paved surface)
V =15-0*(Sf^0-5)(grassed waterway surface)
V =10-0*(Sf^0-5)(nearly bare&untilled surface)
V =9-0*(Sf^0-5)(cultivated straight rows surface)
V =7-0*(Sf^0-5)(short grass pasture surface)
V =5-0*(Sf^0-5)(woodland surface)
V =2-5*(Sf^0-5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation:
V =(1-49*(R^(2/3))*(Sf^0-5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(W)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Pre-Development 002-Year Page 5

Pre-Development 002-Year Page 6
Subbasin Runoff Results
Total Rainfall(in)------------------------------------------------------------3.50
Total Runoff(in)------------------------------------------------------------- 1.18
Peak Runoff(cfs)-----------------------------------------------------------7228
Weighted Curve Number-----------------------------------------------73.00
Time of Concentration(days hh:mm:ss)------------------------0 00-00-00

Pre-Development 002-Year Page 7

Pre-Development 002-Year Page 8
Subbasin:Sub-01
Rainfall Intensity Graph
5
4.8
4.6
44
4.2
4
3.8
3.6
3.4
3.2
3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
so
75
70
65
60
55
50
N 45
0
40
35
30
25
20
15
10
5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Pre-Development 002-Year Page 9

Pre-Development 010-Year Page 1
Project Description
File Name....................................................27842.0004-Pre dvelopment.SPF
Project Options
Flow Units--------------------------------------------------- CFS
Elevation Type Elevation
Hydrology Method. SCS TR-55
Time of Concentration(TOC)Method-------- SCS TR-55
Link Routing Method Hydrodynamic
Enable Overflow Ponding at Nodes------------ YES
Skip Steady State Analysis Time Periods--- NO
Analysis Options
Start Analysis On. Dec 03,2019 00:00:00
End Analysis On. Dec 04,2019 00:00:00
Start Reporting On. Dec 03,2019 00:00:00
Antecedent Dry Days 0 days
Runoff(Dry Weather)Time Step---------------- 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step--------------- 0 00:05:00 days hh:mm:ss
Reporting Time Step----------------------------------- 0 00:05:00 days hh:mm:ss
Routing Time Step-------------------------------------- 1 seconds
Number of Elements
Qty
Rain Gages 1
Subbasins 1
Nodes 1
Junctions 0
Outfalls 1
Flow Diversions 0
Inlets 0
Storage Nodes 0
Links 0
Channels 0
Pipes 0
Pumps 0
Orifices 0
Weirs 0
Outlets 0
Pollutants 0
Land Uses 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
1 Time Series TS-010 Intensity inches North Carolina Union 10 520 SCS Type II 247hr

Pre-Development 010-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 39.76 484.00 73.00 520 2.44 96.94 153.99 0 00-05-00

Pre-Development 010-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft') (cfs) (ft) (ft) (ft)(days hh:mm) (ac-in) (min)
1 Out-01 Outfall 0.00 0.00 0.00

Pre-Development 010-Year Page 4
Subbasin Hydrology
Subbasin : Sub-01
Input Data
Area(ac)------------------------------------------------------------------------39-76
Peak Rate Factor-----------------------------------------------------------484-00
Weighted Curve Number-----------------------------------------------73-00
Rain Gage ID
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
39-76 73-00
Composite Area&Weighted CN 39-76 73-00
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0-007*((n*Lf)^0-8))/((P^0-5)*(Sf^0-4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf =Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf =Slope(ft/ft)
Shallow Concentrated Flow Equation:
V =16-1345*(Sf^0-5)(unpaved surface)
V =20-3282*(Sf^0-5)(paved surface)
V =15-0*(Sf^0-5)(grassed waterway surface)
V =10-0*(Sf^0-5)(nearly bare&untilled surface)
V =9-0*(Sf^0-5)(cultivated straight rows surface)
V =7-0*(Sf^0-5)(short grass pasture surface)
V =5-0*(Sf^0-5)(woodland surface)
V =2-5*(Sf^0-5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation:
V =(1-49*(R^(2/3))*(Sf^0-5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(W)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Pre-Development 010-Year Page 5

Pre-Development 010-Year Page 6
Subbasin Runoff Results
Total Rainfall(in)------------------------------------------------------------520
Total Runoff(in)-------------------------------------------------------------2.44
Peak Runoff(cfs)-----------------------------------------------------------153.99
Weighted Curve Number-----------------------------------------------73.00
Time of Concentration(days hh:mm:ss)------------------------0 00-00-00

Pre-Development 010-Year Page 7

Pre-Development 010-Year Page 8
Subbasin:Sub-01
Rainfall Intensity Graph
75
7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
170
160
150
140
130
120
110
_ 100
N
90
� 80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Pre-Development 010-Year Page 9

Pre-Development 025-Year Page 1
Project Description
File Name....................................................27842.0004-Pre dvelopment.SPF
Project Options
Flow Units--------------------------------------------------- CFS
Elevation Type Elevation
Hydrology Method. SCS TR-55
Time of Concentration(TOC)Method-------- SCS TR-55
Link Routing Method Hydrodynamic
Enable Overflow Ponding at Nodes------------ YES
Skip Steady State Analysis Time Periods--- NO
Analysis Options
Start Analysis On. Dec 03,2019 00:00:00
End Analysis On. Dec 04,2019 00:00:00
Start Reporting On. Dec 03,2019 00:00:00
Antecedent Dry Days 0 days
Runoff(Dry Weather)Time Step---------------- 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step--------------- 0 00:05:00 days hh:mm:ss
Reporting Time Step----------------------------------- 0 00:05:00 days hh:mm:ss
Routing Time Step-------------------------------------- 1 seconds
Number of Elements
Qty
Rain Gages 1
Subbasins 1
Nodes 1
Junctions 0
Outfalls 1
Flow Diversions 0
Inlets 0
Storage Nodes 0
Links 0
Channels 0
Pipes 0
Pumps 0
Orifices 0
Weirs 0
Outlets 0
Pollutants 0
Land Uses 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
1 Time Series TS-025 Intensity inches North Carolina Union 25 6.10 SCS Type II 247hr

Pre-Development 025-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 39.76 484.00 73.00 6.10 3.17 126.13 200.56 0 00-05-00

Pre-Development 025-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft)(days hh:mm) (ac-in) (min)
1 Out-01 Outfall 0.00 0.00 0.00

Pre-Development 025-Year Page 4
Subbasin Hydrology
Subbasin : Sub-01
Input Data
Area(ac)------------------------------------------------------------------------39-76
Peak Rate Factor-----------------------------------------------------------484-00
Weighted Curve Number-----------------------------------------------73-00
Rain Gage ID
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
39-76 73-00
Composite Area&Weighted CN 39-76 73-00
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0-007*((n*Lf)^0-8))/((P^0-5)*(Sf^0-4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf =Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf =Slope(ft/ft)
Shallow Concentrated Flow Equation:
V =16-1345*(Sf^0-5)(unpaved surface)
V =20-3282*(Sf^0-5)(paved surface)
V =15-0*(Sf^0-5)(grassed waterway surface)
V =10-0*(Sf^0-5)(nearly bare&untilled surface)
V =9-0*(Sf^0-5)(cultivated straight rows surface)
V =7-0*(Sf^0-5)(short grass pasture surface)
V =5-0*(Sf^0-5)(woodland surface)
V =2-5*(Sf^0-5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation:
V =(1-49*(R^(2/3))*(Sf^0-5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(W)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Pre-Development 025-Year Page 5

Pre-Development 025-Year Page 6
Subbasin Runoff Results
Total Rainfall(in)------------------------------------------------------------6.10
Total Runoff(in)-------------------------------------------------------------3.17
Peak Runoff(cfs)-----------------------------------------------------------200.56
Weighted Curve Number-----------------------------------------------73.00
Time of Concentration(days hh:mm:ss)------------------------0 00-00-00

Pre-Development 025-Year Page 7

Pre-Development 025-Year Page 8
Subbasin:Sub-01
Rainfall Intensity Graph
8.5
8
7.5
7
65
6
5.5
5
t� 4.5
4
3.5
3
2.6
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
210
200
190
180
170
160
150
140
130
N 120
110
100
� 90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Pre-Development 025-Year Page 9

Pre-Development 050-Year Page 1
Project Description
File Name....................................................27842.0004-Pre dvelopment.SPF
Project Options
Flow Units--------------------------------------------------- CFS
Elevation Type Elevation
Hydrology Method. SCS TR-55
Time of Concentration(TOC)Method-------- SCS TR-55
Link Routing Method Hydrodynamic
Enable Overflow Ponding at Nodes------------ YES
Skip Steady State Analysis Time Periods--- NO
Analysis Options
Start Analysis On. Dec 03,2019 00:00:00
End Analysis On. Dec 04,2019 00:00:00
Start Reporting On. Dec 03,2019 00:00:00
Antecedent Dry Days 0 days
Runoff(Dry Weather)Time Step---------------- 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step--------------- 0 00:05:00 days hh:mm:ss
Reporting Time Step----------------------------------- 0 00:05:00 days hh:mm:ss
Routing Time Step-------------------------------------- 1 seconds
Number of Elements
Qty
Rain Gages 1
Subbasins 1
Nodes 1
Junctions 0
Outfalls 1
Flow Diversions 0
Inlets 0
Storage Nodes 0
Links 0
Channels 0
Pipes 0
Pumps 0
Orifices 0
Weirs 0
Outlets 0
Pollutants 0
Land Uses 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
1 Time Series TS-050 Intensity inches North Carolina Union 50 6.90 SCS Type II 247hr

Pre-Development 050-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 39.76 484.00 73.00 6.90 3.85 153.05 243.14 0 00-05-00

Pre-Development 050-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft') (cfs) (ft) (ft) (ft)(days hh:mm) (ac-in) (min)
1 Out-01 Outfall 0.00 0.00 0.00

Pre-Development 050-Year Page 4
Subbasin Hydrology
Subbasin : Sub-01
Input Data
Area(ac)------------------------------------------------------------------------39-76
Peak Rate Factor-----------------------------------------------------------484-00
Weighted Curve Number-----------------------------------------------73-00
Rain Gage ID
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
39-76 73-00
Composite Area&Weighted CN 39-76 73-00
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0-007*((n*Lf)^0-8))/((P^0-5)*(Sf^0-4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf =Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf =Slope(ft/ft)
Shallow Concentrated Flow Equation:
V =16-1345*(Sf^0-5)(unpaved surface)
V =20-3282*(Sf^0-5)(paved surface)
V =15-0*(Sf^0-5)(grassed waterway surface)
V =10-0*(Sf^0-5)(nearly bare&untilled surface)
V =9-0*(Sf^0-5)(cultivated straight rows surface)
V =7-0*(Sf^0-5)(short grass pasture surface)
V =5-0*(Sf^0-5)(woodland surface)
V =2-5*(Sf^0-5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation:
V =(1-49*(R^(2/3))*(Sf^0-5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(W)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Pre-Development 050-Year Page 5

Pre-Development 050-Year Page 6
Subbasin Runoff Results
Total Rainfall(in)------------------------------------------------------------6.90
Total Runoff(in)-------------------------------------------------------------3.85
Peak Runoff(cfs)-----------------------------------------------------------243.14
Weighted Curve Number-----------------------------------------------73.00
Time of Concentration(days hh:mm:ss)------------------------0 00-00-00

Pre-Development 050-Year Page 7

Pre-Development 050-Year Page 8
Subbasin:Sub-01
Rainfall Intensity Graph
9.5
9
8.5
8
7.5
7
6.5
6
5.5
v� 5
° 4.5
4
3.5
3
2.5
2
1.5
1
0.5 L:L
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
260
250
240
230
220
210
200
190
180
170
160
150
N
140
130
0
120
110
100
90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Pre-Development 050-Year Page 9

Pre-Development 100-Year Page 1
Project Description
File Name....................................................27842.0004-Pre dvelopment.SPF
Project Options
Flow Units--------------------------------------------------- CFS
Elevation Type Elevation
Hydrology Method. SCS TR-55
Time of Concentration(TOC)Method-------- SCS TR-55
Link Routing Method Hydrodynamic
Enable Overflow Ponding at Nodes------------ YES
Skip Steady State Analysis Time Periods--- NO
Analysis Options
Start Analysis On. Dec 03,2019 00:00:00
End Analysis On. Dec 04,2019 00:00:00
Start Reporting On. Dec 03,2019 00:00:00
Antecedent Dry Days 0 days
Runoff(Dry Weather)Time Step---------------- 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step--------------- 0 00:05:00 days hh:mm:ss
Reporting Time Step----------------------------------- 0 00:05:00 days hh:mm:ss
Routing Time Step-------------------------------------- 1 seconds
Number of Elements
Qty
Rain Gages 1
Subbasins 1
Nodes 1
Junctions 0
Outfalls 1
Flow Diversions 0
Inlets 0
Storage Nodes 0
Links 0
Channels 0
Pipes 0
Pumps 0
Orifices 0
Weirs 0
Outlets 0
Pollutants 0
Land Uses 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
1 Time Series TS-100 Intensity inches North Carolina Union 100 7.50 SCS Type II 247

Pre-Development 100-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 39.76 484.00 73.00 7.50 4.37 173.76 275.57 0 00-05-00

Pre-Development 100-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft') (cfs) (ft) (ft) (ft)(days hh:mm) (ac-in) (min)
1 Out-01 Outfall 0.00 0.00 0.00

Pre-Development 100-Year Page 4
Subbasin Hydrology
Subbasin : Sub-01
Input Data
Area(ac)------------------------------------------------------------------------39-76
Peak Rate Factor-----------------------------------------------------------484-00
Weighted Curve Number-----------------------------------------------73-00
Rain Gage ID
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
39-76 73-00
Composite Area&Weighted CN 39-76 73-00
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0-007*((n*Lf)^0-8))/((P^0-5)*(Sf^0-4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf =Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf =Slope(ft/ft)
Shallow Concentrated Flow Equation:
V =16-1345*(Sf^0-5)(unpaved surface)
V =20-3282*(Sf^0-5)(paved surface)
V =15-0*(Sf^0-5)(grassed waterway surface)
V =10-0*(Sf^0-5)(nearly bare&untilled surface)
V =9-0*(Sf^0-5)(cultivated straight rows surface)
V =7-0*(Sf^0-5)(short grass pasture surface)
V =5-0*(Sf^0-5)(woodland surface)
V =2-5*(Sf^0-5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation:
V =(1-49*(R^(2/3))*(Sf^0-5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(W)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Pre-Development 100-Year Page 5

Pre-Development 100-Year Page 6
Subbasin Runoff Results
Total Rainfall(in)------------------------------------------------------------7.50
Total Runoff(in)-------------------------------------------------------------4.37
Peak Runoff(cfs)-----------------------------------------------------------275.57
Weighted Curve Number-----------------------------------------------73.00
Time of Concentration(days hh:mm:ss)------------------------0 00-00-00

Pre-Development 100-Year Page 7

Pre-Development 100-Year Page 8
Subbasin:Sub-01
Rainfall Intensity Graph
10.5
10
9.5
9
8.5
8
7.5
7
6.5
� 6
`6 5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
290
280
270
260
250
240
230
220
210
200
190
180
_ 170
160
150
0 140
� 130
120
110
100
90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Pre-Development 100-Year Page 9

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX D
POST-DEVELOPMENT
DRAINAGE MAP
27842.0004
T
THOMAS & HUTTON

PID:O 27026 PATRICIA RAU CI
AUBREY INSON & � \ DB:3540 P .024
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/ • •• • •• _ a - �-" ` // i/ � -' • •••• •_�;'- \ � � I .• DB:3801 P 703 DB:D128 PG:0254 60 PUBLIC R W
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06009032
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APPROXIMATE LOC TION OF
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SUB-01 '' ` ��. (BASE B ARIN - R PHIC DESIGNED: LSE
PID:06030008A "' "" -
SAMUEL KOENIGSBERG AREA: 7.97 AC. --- 2076.88'(TOTAL) Cr A C ALE REVIEWED: MSK
/ DB:4460 PG:523 _ -_ _--_` PID: 06009023 APPROVED: MSK
ZONING:R-40 CN: 72 PID: 0600 21 WILLAVENE BRA AM ET
-1 PID: 06 015
/ ftOB€RL & _ STACK JOY ALEXANDER ANNE A BOA:043 200 0 100 200 400 800
Tc: 22 MIN. z _; DB:0896 PG:0463 SCALE: 1" = 200'
ioh4RY- 765. ANDER DB:7265 PG:156 W
DB:7265 ZONING:R-40 ZONING:R-40 �
R-40
PID:06009040
I ( IN FEET WINDING CREEK HOMEOWNERS
ASSOCIATION
DB:5920 PG:659
1 inch = 200 ft. COMMON OPEN SPACE
i z ZONING:R-40 C3 * 30.j

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX E
POST-DEVELOPMENT CONDITIONS
DRAINAGE CALCULATIONS
27842.0004
T
THOMAS & HUTTON

27842.0004
CRESSWIND WESLEY CHAPEL - PHASE 04
POST-DEVELOPMENT BASINS MODEL
0/0
FIERSPILLWAV
PoNDD5
j�ORI
�1
CS
PoNPOS
ORIFICE
�1
CIIR£fFIPE

Post-Development 002-Year Page 1
Project Description
File Name................................................. 27842.0004-Post.SPF
Project Options
Flow Units................................................ CFS
Elevation Type.......................................... Elevation
Hydrology Method................................... SCS TR-55
Time of Concentration(TOC)Method.......SCS TR-55
Link Routing Method................................ Hydrodynamic
Enable Overflow Ponding at Nodes.......... YES
Skip Steady State Analysis Time Periods... NO
Analysis Options
Start Analysis On...................................... 00:00:00 0:00:00
End Analysis On........................................ 00:00:00 0:00:00
Start Reporting On................................... 00:00:00 0:00:00
Antecedent Dry Days................................ 0 days
Runoff(Dry Weather)Time Step.............. 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step............. 0 00:05:00 days hh:mm:ss
Reporting Time Step................................. 0 00:05:00 days hh:mm:ss
Routing Time Step.................................... 1 seconds
Number of Elements
my
RainGages............................................... 1
Subbasins.................................................. 2
Nodes........................................................ 4
Junctions.......................................... 1
Outfalls............................................ 2
Flow Diversions................................ 0
Inlets................................................ 0
Storage Nodes.................................. 1
Links.......................................................... 5
Channels.......................................... 0
Pipes................................................ 1
Pumps.............................................. 0
Orifices............................................. 2
Weirs................................................ 2
Outlets............................................. 0
Pollutants................................................. 0
LandUses................................................. 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
49 Time Series TS-002 Intensity inches North Carolina Union 2.00 3.50 SCS Type III 24-hr

Post-Development 002-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 7.97 0.00 72.00 3.50 1.12 8.93 6.51 0 00:21:18
2 Sub-05 42.25 484.00 88.63 3.50 2.32 98.19 100.20 0 00:05:00

Post-Development 002-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft) (days hh:mm) (ac-in) (min)
1 CS Junction 570.00 578.50 0.00 9999.00 1.00 24.87 571.43 0.00 7.07 0 00:00 0.00 0.00
2 OUT-02 Outfall 569.00 30.03 570.12
3 OUT-SPILLWAY-02 Outfall 569.00 0.00 569.00
4 POND-05 Storage Node 570.00 580.00 574.50 1.00 99.03 577.73 0.00 0.00

Post-Development 002-Year Page 4
Link Summary
SN Element Element From To(Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft) (ft) (ft) N (in) (cfs) (cfs) (ft/sec) (ft) (min)
1 OUTLET-PIPE Pipe CS OUT-02 80.00 570.00 569.00 1.2500 42.000 0.0130 24.87 112.49 0.22 7.86 1.27 0.36 0.00 Calculated
2 CS-RIM Orifice POND-05 CS 570.00 570.00 60.000 0.00
3 ORIFICE Orifice POND-05 CS 570.00 570.00 4.000 0.75
4 EMER-SPILLWAY Weir POND-05 OUT-SPILLWAY-02 570.00 569.00 0.00
5 WEIR Weir POND-05 CS 570.00 570.00 24.12

Post-Development 002-Year Page 5
Subbasin Hydrology
Subbasin:Sub-01
Input Data
Area(ac)............................................................................... 7.97
Peak Rate Factor.................................................................. 0
Weighted Curve Number...................................................... 72
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
7.97 72
Composite Area&Weighted CN 7.97 72
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0.007*((n*Lf)^O.8))/((P^O.5)*(Sf^O.4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf=Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf=Slope(ft/ft)
Shallow Concentrated Flow Equation
V =16.1345*(Sf^0.5)(unpaved surface)
V =20.3282*(Sf^0.5)(paved surface)
V =15.0*(Sf^0.5)(grassed waterway surface)
V =10.0*(Sf^0.5)(nearly bare&untilled surface)
V =9.0*(Sf^0.5)(cultivated straight rows surface)
V =7.0*(Sf^0.5)(short grass pasture surface)
V =5.0*(Sf^0.5)(woodland surface)
V =2.5*(Sf^0.5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation
V =(1.49*(R^(2/3))*(Sf^0.5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(ft2)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Post-Development 002-Year Page 6
Subarea Subarea Subarea
Sheet Flow Computations A B C
Manning's Roughness: 0.3 0 0
Flow Length(ft): 100 0 0
Slope(%): 1.89 0 0
2 yr,24 hr Rainfall(in): 3.5 0 0
Velocity(ft/sec): 0.1 0 0
Computed Flow Time(min): 16.69 0 0
Subarea Subarea Subarea
Shallow Concentrated Flow Computations A B C
Flow Length(ft): 615 0 0
Slope(%): 1.89 0 0
Surface Type: Unpaved Unpaved Unpaved
Velocity(ft/sec): 2.22 0 0
Computed Flow Time(min): 4.62 0 0
Total TOC(min)..................21.30
Subbasin Runoff Results
Total Rainfall(in).................................................................. 3.5
Total Runoff(in)................................................................... 1.12
Peak Runoff(cfs).................................................................. 6.51
Weighted Curve Number...................................................... 72
Time of Concentration(days hh:mm:ss)............................... 0 00:21:18

Post-Development 002-Year Page 7
Subbasin:Sub-01
Rainfall Intensity Graph
3
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2
1.9
1.8
z 1.7
1.6
- 1.5
m
`c 1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
7
6.5
6
5.5
5
4.5
N 4
U
3.5
`0
c
c
� 3
2.5
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 002-Year Page 8
Subbasin:Sub-05
Input Data
Area(ac)...............................................................................42.25
Peak Rate Factor.................................................................. 484
Weighted Curve Number...................................................... 88.63
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
15.22 - 72
Paved parking&roofs 27.03 D 98
Composite Area&Weighted CN 42.25 88.63
Time of Concentration
User-Defined TOC override(minutes):5
Subbasin Runoff Results
Total Rainfall(in).................................................................. 3.5
Total Runoff(in)................................................................... 2.32
Peak Runoff(cfs).................................................................. 100.2
Weighted Curve Number...................................................... 88.63
Time of Concentration(days hh:mm:ss)............................... 0 00:05:00

Post-Development 002-Year Page 9
Subbasin:Sub-05
Rainfall Intensity Graph
3.1
3
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2
1.9
z
1.8
c 1.7
1.6
m 1.5
`9 14
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
105
100
95
90
85
80
75
70
65
N 60
55
50
(If 45
40
35
30
25
20
15
10
5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 002-Year Page 10
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No.of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) N (in) (in) (cfs)
1 OUTLET-PIPE 80.00 570.00 0.00 569.00 0.00 1.00 1.2500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No 1

Post-Development 002-Year Page 11
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 OUTLET-PIPE 24.87 0 12:33 112.49 0.22 7.86 0.17 1.27 0.36 0.00 Calculated

Post-Development 002-Year Page 12
Storage Nodes
Storage Node:POND-05
Input Data
Invert Elevation(ft)........................................................................ 570.00
Max(Rim)Elevation(ft).................................................................. 580.00
Max(Rim)Offset(ft)...................................................................... 10.00
Initial Water Elevation(ft).............................................................. 574.50
Initial Water Depth(ft)................................................................... 4.50
Ponded Area(ft2)............................................................................ 1.00
Evaporation Loss............................................................................ 0.00
Outflow Weirs
SN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EMER-SPILLWAY Trapezoidal No 578.50 8.50 20.00 1.50 3.33
2 WEIR Rectangular No 576.40 6.40 5.00 2.10 3.33
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CS-RIM Bottom Rectangular No 60.00 60.00 578.50 0.63
2 ORIFICE Side CIRCULAR No 4.00 574.50 0.61
Output Summary Results
Peak Inflow(cfs)............................................................................. 99.03
Peak Lateral Inflow(cfs)................................................................. 99.03
Peak Outflow(cfs).......................................................................... 24.87
Peak Exfiltration Flow Rate(cfm).................................................... 0
Max HGL Elevation Attained(ft)..................................................... 577.73
Max HGL Depth Attained(ft).......................................................... 7.73
Average HGL Elevation Attained(ft)............................................... 575.72
Average HGL Depth Attained(ft).................................................... 5.72
Time of Max HGL Occurrence(days hh:mm)...................................0 12:33
Total Exfiltration Volume(1000-ft3)................................................ 0
Total Flooded Volume(ac-in).......................................................... 0
Total Time Flooded(min)................................................................0
Total Retention Time(sec).............................................................. 0

Post-Development 010-Year Page 1
Project Description
File Name................................................. 27842.0004-Post.SPF
Project Options
Flow Units................................................ CFS
Elevation Type.......................................... Elevation
Hydrology Method................................... SCS TR-55
Time of Concentration(TOC)Method.......SCS TR-55
Link Routing Method................................ Hydrodynamic
Enable Overflow Ponding at Nodes.......... YES
Skip Steady State Analysis Time Periods... NO
Analysis Options
Start Analysis On...................................... 00:00:00 0:00:00
End Analysis On........................................ 00:00:00 0:00:00
Start Reporting On................................... 00:00:00 0:00:00
Antecedent Dry Days................................ 0 days
Runoff(Dry Weather)Time Step.............. 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step............. 0 00:05:00 days hh:mm:ss
Reporting Time Step................................. 0 00:05:00 days hh:mm:ss
Routing Time Step.................................... 1 seconds
Number of Elements
my
RainGages............................................... 1
Subbasins.................................................. 2
Nodes........................................................ 4
Junctions.......................................... 1
Outfalls............................................ 2
Flow Diversions................................ 0
Inlets................................................ 0
Storage Nodes.................................. 1
Links.......................................................... 5
Channels.......................................... 0
Pipes................................................ 1
Pumps.............................................. 0
Orifices............................................. 2
Weirs................................................ 2
Outlets............................................. 0
Pollutants................................................. 0
LandUses................................................. 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
49 Time Series TS-010 Intensity inches North Carolina Union 10.00 5.20 SCS Type III 24-hr

Post-Development 010-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 7.97 0.00 72.00 5.20 2.35 18.74 14.35 0 00:21:18
2 Sub-05 42.25 484.00 88.63 5.20 3.93 165.83 164.22 0 00:05:00

Post-Development 010-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft) (days hh:mm) (ac-in) (min)
1 CS Junction 570.00 578.50 0.00 9999.00 1.00 69.15 572.80 0.00 5.70 0 00:00 0.00 0.00
2 OUT-02 Outfall 569.00 83.45 570.98
3 OUT-SPILLWAY-02 Outfall 569.00 15.05 569.00
4 POND-05 Storage Node 570.00 580.00 574.50 1.00 163.01 578.86 0.00 0.00

Post-Development 010-Year Page 4
Link Summary
SN Element Element From To(Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft) (ft) (ft) N (in) (cfs) (cfs) (ft/sec) (ft) (min)
1 OUTLET-PIPE Pipe CS OUT-02 80.00 570.00 569.00 1.2500 42.000 0.0130 69.15 112.49 0.61 9.88 2.39 0.68 0.00 Calculated
2 CS-RIM Orifice POND-05 CS 570.00 570.00 60.000 14.46
3 ORIFICE Orifice POND-05 CS 570.00 570.00 4.000 0.88
4 EMER-SPILLWAY Weir POND-05 OUT-SPILLWAY-02 570.00 569.00 15.05
5 WEIR Weir POND-05 CS 570.00 570.00 53.82

Post-Development 010-Year Page 5
Subbasin Hydrology
Subbasin:Sub-01
Input Data
Area(ac)............................................................................... 7.97
Peak Rate Factor.................................................................. 0
Weighted Curve Number...................................................... 72
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
7.97 72
Composite Area&Weighted CN 7.97 72
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0.007*((n*Lf)^O.8))/((P^O.5)*(Sf^O.4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf=Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf=Slope(ft/ft)
Shallow Concentrated Flow Equation
V =16.1345*(Sf^0.5)(unpaved surface)
V =20.3282*(Sf^0.5)(paved surface)
V =15.0*(Sf^0.5)(grassed waterway surface)
V =10.0*(Sf^0.5)(nearly bare&untilled surface)
V =9.0*(Sf^0.5)(cultivated straight rows surface)
V =7.0*(Sf^0.5)(short grass pasture surface)
V =5.0*(Sf^0.5)(woodland surface)
V =2.5*(Sf^0.5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation
V =(1.49*(R^(2/3))*(Sf^0.5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(ft2)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Post-Development 010-Year Page 6
Subarea Subarea Subarea
Sheet Flow Computations A B C
Manning's Roughness: 0.3 0 0
Flow Length(ft): 100 0 0
Slope(%): 1.89 0 0
2 yr,24 hr Rainfall(in): 3.5 0 0
Velocity(ft/sec): 0.1 0 0
Computed Flow Time(min): 16.69 0 0
Subarea Subarea Subarea
Shallow Concentrated Flow Computations A B C
Flow Length(ft): 615 0 0
Slope(%): 1.89 0 0
Surface Type: Unpaved Unpaved Unpaved
Velocity(ft/sec): 2.22 0 0
Computed Flow Time(min): 4.62 0 0
Total TOC(min)..................21.30
Subbasin Runoff Results
Total Rainfall(in).................................................................. 5.2
Total Runoff(in)................................................................... 2.35
Peak Runoff(cfs).................................................................. 14.35
Weighted Curve Number...................................................... 72
Time of Concentration(days hh:mm:ss)............................... 0 00:21:18

Post-Development 010-Year Page 7
Subbasin:Sub-01
Rainfall Intensity Graph
4.4
4.z
a
3.8
3.6
3.4
3.2
3
2.8
2.6
z
c 2.4
m
2.2
`c 2
� 1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
15.5
15
14.5
14
13.5
13
12.5
12
11.5
11
10.5
10
9.5
9
w 8.5
U
6
`0 7.5
= 7
6.5
6
5.5
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0 1 z 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 010-Year Page 8
Subbasin:Sub-05
Input Data
Area(ac)...............................................................................42.25
Peak Rate Factor.................................................................. 484
Weighted Curve Number...................................................... 88.63
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
15.22 - 72
Paved parking&roofs 27.03 D 98
Composite Area&Weighted CN 42.25 88.63
Time of Concentration
User-Defined TOC override(minutes):5
Subbasin Runoff Results
Total Rainfall(in).................................................................. 5.2
Total Runoff(in)................................................................... 3.93
Peak Runoff(cfs).................................................................. 164.22
Weighted Curve Number...................................................... 88.63
Time of Concentration(days hh:mm:ss)............................... 0 00:05:00

Post-Development 010-Year Page 9
Subbasin:Sub-05
Rainfall Intensity Graph
4.s
4.a
4.2
4
3.8
3.6
3.4
3.2
3
2.8
z 2.6
c
._. 2.4
2.2
`c
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
180
170
160
150
140
130
120
110
N 1oo
U
90
O
C
� 80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 010-Year Page 10
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No.of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) N (in) (in) (cfs)
1 OUTLET-PIPE 80.00 570.00 0.00 569.00 0.00 1.00 1.2500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No 1

Post-Development 010-Year Page 11
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 OUTLET-PIPE 69.15 0 12:19 112.49 0.61 9.88 0.13 2.39 0.68 0.00 Calculated

Post-Development 010-Year Page 12
Storage Nodes
Storage Node:POND-05
Input Data
Invert Elevation(ft)........................................................................ 570.00
Max(Rim)Elevation(ft).................................................................. 580.00
Max(Rim)Offset(ft)...................................................................... 10.00
Initial Water Elevation(ft).............................................................. 574.50
Initial Water Depth(ft)................................................................... 4.50
Ponded Area(ft2)............................................................................ 1.00
Evaporation Loss............................................................................ 0.00
Outflow Weirs
SN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EMER-SPILLWAY Trapezoidal No 578.50 8.50 20.00 1.50 3.33
2 WEIR Rectangular No 576.40 6.40 5.00 2.10 3.33
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CS-RIM Bottom Rectangular No 60.00 60.00 578.50 0.63
2 ORIFICE Side CIRCULAR No 4.00 574.50 0.61
Output Summary Results
Peak Inflow(cfs)............................................................................. 163.01
Peak Lateral Inflow(cfs)................................................................. 163.01
Peak Outflow(cfs).......................................................................... 84.2
Peak Exfiltration Flow Rate(cfm).................................................... 0
Max HGL Elevation Attained(ft)..................................................... 578.86
Max HGL Depth Attained(ft).......................................................... 8.86
Average HGL Elevation Attained(ft)............................................... 575.92
Average HGL Depth Attained(ft).................................................... 5.92
Time of Max HGL Occurrence(days hh:mm)...................................0 12:19
Total Exfiltration Volume(1000-ft3)................................................ 0
Total Flooded Volume(ac-in).......................................................... 0
Total Time Flooded(min)................................................................0
Total Retention Time(sec).............................................................. 0

Post-Development 025-Year Page 1
Project Description
File Name................................................. 27842.0004-Post.SPF
Project Options
Flow Units................................................ CFS
Elevation Type.......................................... Elevation
Hydrology Method................................... SCS TR-55
Time of Concentration(TOC)Method.......SCS TR-55
Link Routing Method................................ Hydrodynamic
Enable Overflow Ponding at Nodes.......... YES
Skip Steady State Analysis Time Periods... NO
Analysis Options
Start Analysis On...................................... 00:00:00 0:00:00
End Analysis On........................................ 00:00:00 0:00:00
Start Reporting On................................... 00:00:00 0:00:00
Antecedent Dry Days................................ 0 days
Runoff(Dry Weather)Time Step.............. 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step............. 0 00:05:00 days hh:mm:ss
Reporting Time Step................................. 0 00:05:00 days hh:mm:ss
Routing Time Step.................................... 1 seconds
Number of Elements
my
RainGages............................................... 1
Subbasins.................................................. 2
Nodes........................................................ 4
Junctions.......................................... 1
Outfalls............................................ 2
Flow Diversions................................ 0
Inlets................................................ 0
Storage Nodes.................................. 1
Links.......................................................... 5
Channels.......................................... 0
Pipes................................................ 1
Pumps.............................................. 0
Orifices............................................. 2
Weirs................................................ 2
Outlets............................................. 0
Pollutants................................................. 0
LandUses................................................. 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
49 Time Series TS-025 Intensity inches North Carolina Union 25.00 6.10 SCS Type III 24-hr

Post-Development 025-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 7.97 0.00 72.00 6.10 3.08 24.50 18.90 0 00:21:18
2 Sub-05 42.25 484.00 88.63 6.10 4.79 202.42 197.93 0 00:05:00

Post-Development 025-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft) (days hh:mm) (ac-in) (min)
1 CS Junction 570.00 578.50 0.00 9999.00 1.00 95.66 574.06 0.00 4.44 0 00:00 0.00 0.00
2 OUT-02 Outfall 569.00 112.98 571.48
3 OUT-SPILLWAY-02 Outfall 569.00 38.13 569.00
4 POND-05 Storage Node 570.00 580.00 574.50 1.00 196.68 579.16 0.00 0.00

Post-Development 025-Year Page 4
Link Summary
SN Element Element From To(Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft) (ft) (ft) N (in) (cfs) (cfs) (ft/sec) (ft) (min)
1 OUTLET-PIPE Pipe CS OUT-02 80.00 570.00 569.00 1.2500 42.000 0.0130 95.66 112.49 0.85 10.93 2.99 0.85 0.00 Calculated
2 CS-RIM Orifice POND-05 CS 570.00 570.00 60.000 35.54
3 ORIFICE Orifice POND-05 CS 570.00 570.00 4.000 0.91
4 EMER-SPILLWAY Weir POND-05 OUT-SPILLWAY-02 570.00 569.00 38.13
5 WEIR Weir POND-05 CS 570.00 570.00 59.21

Post-Development 025-Year Page 5
Subbasin Hydrology
Subbasin:Sub-01
Input Data
Area(ac)............................................................................... 7.97
Peak Rate Factor.................................................................. 0
Weighted Curve Number...................................................... 72
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
7.97 72
Composite Area&Weighted CN 7.97 72
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0.007*((n*Lf)^O.8))/((P^O.5)*(Sf^O.4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf=Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf=Slope(ft/ft)
Shallow Concentrated Flow Equation
V =16.1345*(Sf^0.5)(unpaved surface)
V =20.3282*(Sf^0.5)(paved surface)
V =15.0*(Sf^0.5)(grassed waterway surface)
V =10.0*(Sf^0.5)(nearly bare&untilled surface)
V =9.0*(Sf^0.5)(cultivated straight rows surface)
V =7.0*(Sf^0.5)(short grass pasture surface)
V =5.0*(Sf^0.5)(woodland surface)
V =2.5*(Sf^0.5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation
V =(1.49*(R^(2/3))*(Sf^0.5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(ft2)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Post-Development 025-Year Page 6
Subarea Subarea Subarea
Sheet Flow Computations A B C
Manning's Roughness: 0.3 0 0
Flow Length(ft): 100 0 0
Slope(%): 1.89 0 0
2 yr,24 hr Rainfall(in): 3.5 0 0
Velocity(ft/sec): 0.1 0 0
Computed Flow Time(min): 16.69 0 0
Subarea Subarea Subarea
Shallow Concentrated Flow Computations A B C
Flow Length(ft): 615 0 0
Slope(%): 1.89 0 0
Surface Type: Unpaved Unpaved Unpaved
Velocity(ft/sec): 2.22 0 0
Computed Flow Time(min): 4.62 0 0
Total TOC(min)..................21.30
Subbasin Runoff Results
Total Rainfall(in).................................................................. 6.1
Total Runoff(in)................................................................... 3.08
Peak Runoff(cfs).................................................................. 18.9
Weighted Curve Number...................................................... 72
Time of Concentration(days hh:mm:ss)............................... 0 00:21:18

Post-Development 025-Year Page 7
Subbasin:Sub-01
Rainfall Intensity Graph
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
z 3
c 2.8
m
2.6
`c 2.4
m 2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
z0
1s
18
17
1s
15
14
13
12
11
U
10
O
� 9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 025-Year Page 8
Subbasin:Sub-05
Input Data
Area(ac)...............................................................................42.25
Peak Rate Factor.................................................................. 484
Weighted Curve Number...................................................... 88.63
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
15.22 - 72
Paved parking&roofs 27.03 D 98
Composite Area&Weighted CN 42.25 88.63
Time of Concentration
User-Defined TOC override(minutes):5
Subbasin Runoff Results
Total Rainfall(in).................................................................. 6.1
Total Runoff(in)................................................................... 4.79
Peak Runoff(cfs).................................................................. 197.93
Weighted Curve Number...................................................... 88.63
Time of Concentration(days hh:mm:ss)............................... 0 00:05:00

Post-Development 025-Year Page 9
Subbasin:Sub-05
Rainfall Intensity Graph
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
z 3
c
2.8
m 2.6
24
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
210
200
190
180
170
160
150
140
130
N 120
110
100
(if 90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 025-Year Page 10
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No.of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) N (in) (in) (cfs)
1 OUTLET-PIPE 80.00 570.00 0.00 569.00 0.00 1.00 1.2500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No 1

Post-Development 025-Year Page 11
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 OUTLET-PIPE 95.66 0 12:15 112.49 0.85 10.93 0.12 2.99 0.85 0.00 Calculated

Post-Development 025-Year Page 12
Storage Nodes
Storage Node:POND-05
Input Data
Invert Elevation(ft)........................................................................ 570.00
Max(Rim)Elevation(ft).................................................................. 580.00
Max(Rim)Offset(ft)...................................................................... 10.00
Initial Water Elevation(ft).............................................................. 574.50
Initial Water Depth(ft)................................................................... 4.50
Ponded Area(ft2)............................................................................ 1.00
Evaporation Loss............................................................................ 0.00
Outflow Weirs
SN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EMER-SPILLWAY Trapezoidal No 578.50 8.50 20.00 1.50 3.33
2 WEIR Rectangular No 576.40 6.40 5.00 2.10 3.33
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CS-RIM Bottom Rectangular No 60.00 60.00 578.50 0.63
2 ORIFICE Side CIRCULAR No 4.00 574.50 0.61
Output Summary Results
Peak Inflow(cfs)............................................................................. 196.68
Peak Lateral Inflow(cfs)................................................................. 196.68
Peak Outflow(cfs).......................................................................... 133.79
Peak Exfiltration Flow Rate(cfm).................................................... 0
Max HGL Elevation Attained(ft)..................................................... 579.16
Max HGL Depth Attained(ft).......................................................... 9.16
Average HGL Elevation Attained(ft)............................................... 576.02
Average HGL Depth Attained(ft).................................................... 6.02
Time of Max HGL Occurrence(days hh:mm)...................................0 12:15
Total Exfiltration Volume(1000-ft3)................................................ 0
Total Flooded Volume(ac-in).......................................................... 0
Total Time Flooded(min)................................................................0
Total Retention Time(sec).............................................................. 0

Post-Development 050-Year Page 1
Project Description
File Name................................................. 27842.0004-Post.SPF
Project Options
Flow Units................................................ CFS
Elevation Type.......................................... Elevation
Hydrology Method................................... SCS TR-55
Time of Concentration(TOC)Method.......SCS TR-55
Link Routing Method................................ Hydrodynamic
Enable Overflow Ponding at Nodes.......... YES
Skip Steady State Analysis Time Periods... NO
Analysis Options
Start Analysis On...................................... 00:00:00 0:00:00
End Analysis On........................................ 00:00:00 0:00:00
Start Reporting On................................... 00:00:00 0:00:00
Antecedent Dry Days................................ 0 days
Runoff(Dry Weather)Time Step.............. 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step............. 0 00:05:00 days hh:mm:ss
Reporting Time Step................................. 0 00:05:00 days hh:mm:ss
Routing Time Step.................................... 1 seconds
Number of Elements
my
RainGages............................................... 1
Subbasins.................................................. 2
Nodes........................................................ 4
Junctions.......................................... 1
Outfalls............................................ 2
Flow Diversions................................ 0
Inlets................................................ 0
Storage Nodes.................................. 1
Links.......................................................... 5
Channels.......................................... 0
Pipes................................................ 1
Pumps.............................................. 0
Orifices............................................. 2
Weirs................................................ 2
Outlets............................................. 0
Pollutants................................................. 0
LandUses................................................. 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
49 Time Series TS-050 Intensity inches North Carolina Union 50.00 6.90 SCS Type III 24-hr

Post-Development 050-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 7.97 0.00 72.00 6.90 3.74 29.82 23.06 0 00:21:18
2 Sub-05 42.25 484.00 88.63 6.90 5.57 235.25 227.79 0 00:05:00

Post-Development 050-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft) (days hh:mm) (ac-in) (min)
1 CS Junction 570.00 578.50 0.00 9999.00 1.00 116.23 575.83 0.00 2.67 0 00:00 0.00 0.00
2 OUT-02 Outfall 569.00 136.57 572.50
3 OUT-SPILLWAY-02 Outfall 569.00 57.85 569.00
4 POND-05 Storage Node 570.00 580.00 574.50 1.00 226.49 579.36 0.00 0.00

Post-Development 050-Year Page 4
Link Summary
SN Element Element From To(Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft) (ft) (ft) N (in) (cfs) (cfs) (ft/sec) (ft) (min)
1 OUTLET-PIPE Pipe CS OUT-02 80.00 570.00 569.00 1.2500 42.000 0.0130 116.24 112.49 1.03 12.33 3.50 1.00 5.00 SURCHARGED
2 CS-RIM Orifice POND-05 CS 570.00 570.00 60.000 52.85
3 ORIFICE Orifice POND-05 CS 570.00 570.00 4.000 0.92
4 EMER-SPILLWAY Weir POND-05 OUT-SPILLWAY-02 570.00 569.00 57.85
5 WEIR Weir POND-05 CS 570.00 570.00 62.57

Post-Development 050-Year Page 5
Subbasin Hydrology
Subbasin:Sub-01
Input Data
Area(ac)............................................................................... 7.97
Peak Rate Factor.................................................................. 0
Weighted Curve Number...................................................... 72
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
7.97 72
Composite Area&Weighted CN 7.97 72
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0.007*((n*Lf)^O.8))/((P^O.5)*(Sf^O.4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf=Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf=Slope(ft/ft)
Shallow Concentrated Flow Equation
V =16.1345*(Sf^0.5)(unpaved surface)
V =20.3282*(Sf^0.5)(paved surface)
V =15.0*(Sf^0.5)(grassed waterway surface)
V =10.0*(Sf^0.5)(nearly bare&untilled surface)
V =9.0*(Sf^0.5)(cultivated straight rows surface)
V =7.0*(Sf^0.5)(short grass pasture surface)
V =5.0*(Sf^0.5)(woodland surface)
V =2.5*(Sf^0.5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation
V =(1.49*(R^(2/3))*(Sf^0.5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(ft2)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Post-Development 050-Year Page 6
Subarea Subarea Subarea
Sheet Flow Computations A B C
Manning's Roughness: 0.3 0 0
Flow Length(ft): 100 0 0
Slope(%): 1.89 0 0
2 yr,24 hr Rainfall(in): 3.5 0 0
Velocity(ft/sec): 0.1 0 0
Computed Flow Time(min): 16.69 0 0
Subarea Subarea Subarea
Shallow Concentrated Flow Computations A B C
Flow Length(ft): 615 0 0
Slope(%): 1.89 0 0
Surface Type: Unpaved Unpaved Unpaved
Velocity(ft/sec): 2.22 0 0
Computed Flow Time(min): 4.62 0 0
Total TOC(min)..................21.30
Subbasin Runoff Results
Total Rainfall(in).................................................................. 6.9
Total Runoff(in)................................................................... 3.74
Peak Runoff(cfs).................................................................. 23.06
Weighted Curve Number...................................................... 72
Time of Concentration(days hh:mm:ss)............................... 0 00:21:18

Post-Development 050-Year Page 7
Subbasin:Sub-01
Rainfall Intensity Graph
s
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
z 3.4
3.2
— 3
m
`c 2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
25
24
23
22
21
20
19
18
17
16
15
n 14
13
`0 12
c
c 11
10
9
8
7
6
5
4
3 -
2 -
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 050-Year Page S
Subbasin:Sub-05
Input Data
Area(ac)...............................................................................42.25
Peak Rate Factor.................................................................. 484
Weighted Curve Number...................................................... 88.63
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
15.22 - 72
Paved parking&roofs 27.03 D 98
Composite Area&Weighted CN 42.25 88.63
Time of Concentration
User-Defined TOC override(minutes):5
Subbasin Runoff Results
Total Rainfall(in).................................................................. 6.9
Total Runoff(in)................................................................... 5.57
Peak Runoff(cfs).................................................................. 227.79
Weighted Curve Number...................................................... 88.63
Time of Concentration(days hh:mm:ss)............................... 0 00:05:00

Post-Development 050-Year Page 9
Subbasin:Sub-05
Rainfall Intensity Graph
6.z
s
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
z
3.6
� 3.4
3.2
m 3
`9 28
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
240
230
220
210
200
190
180
170
160
150
140
� 130
w 120
0
S 110
100
90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 050-Year Page 10
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No.of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) N (in) (in) (cfs)
1 OUTLET-PIPE 80.00 570.00 0.00 569.00 0.00 1.00 1.2500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No 1

Post-Development 050-Year Page 11
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 OUTLET-PIPE 116.24 0 12:14 112.49 1.03 12.33 0.11 3.50 1.00 5.00 SURCHARGED

Post-Development 050-Year Page 12
Storage Nodes
Storage Node:POND-05
Input Data
Invert Elevation(ft)........................................................................ 570.00
Max(Rim)Elevation(ft).................................................................. 580.00
Max(Rim)Offset(ft)...................................................................... 10.00
Initial Water Elevation(ft).............................................................. 574.50
Initial Water Depth(ft)................................................................... 4.50
Ponded Area(ft2)............................................................................ 1.00
Evaporation Loss............................................................................ 0.00
Outflow Weirs
SN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EMER-SPILLWAY Trapezoidal No 578.50 8.50 20.00 1.50 3.33
2 WEIR Rectangular No 576.40 6.40 5.00 2.10 3.33
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CS-RIM Bottom Rectangular No 60.00 60.00 578.50 0.63
2 ORIFICE Side CIRCULAR No 4.00 574.50 0.61
Output Summary Results
Peak Inflow(cfs)............................................................................. 226.49
Peak Lateral Inflow(cfs)................................................................. 226.49
Peak Outflow(cfs).......................................................................... 174.08
Peak Exfiltration Flow Rate(cfm).................................................... 0
Max HGL Elevation Attained(ft)..................................................... 579.36
Max HGL Depth Attained(ft).......................................................... 9.36
Average HGL Elevation Attained(ft)............................................... 576.1
Average HGL Depth Attained(ft).................................................... 6.1
Time of Max HGL Occurrence(days hh:mm)...................................0 12:14
Total Exfiltration Volume(1000-ft3)................................................ 0
Total Flooded Volume(ac-in).......................................................... 0
Total Time Flooded(min)................................................................0
Total Retention Time(sec).............................................................. 0

Post-Development 100-Year Page 1
Project Description
File Name................................................. 27842.0004-Post.SPF
Project Options
Flow Units................................................ CFS
Elevation Type.......................................... Elevation
Hydrology Method................................... SCS TR-55
Time of Concentration(TOC)Method.......SCS TR-55
Link Routing Method................................ Hydrodynamic
Enable Overflow Ponding at Nodes.......... YES
Skip Steady State Analysis Time Periods... NO
Analysis Options
Start Analysis On...................................... 00:00:00 0:00:00
End Analysis On........................................ 00:00:00 0:00:00
Start Reporting On................................... 00:00:00 0:00:00
Antecedent Dry Days................................ 0 days
Runoff(Dry Weather)Time Step.............. 0 01:00:00 days hh:mm:ss
Runoff(Wet Weather)Time Step............. 0 00:05:00 days hh:mm:ss
Reporting Time Step................................. 0 00:05:00 days hh:mm:ss
Routing Time Step.................................... 1 seconds
Number of Elements
my
RainGages............................................... 1
Subbasins.................................................. 2
Nodes........................................................ 4
Junctions.......................................... 1
Outfalls............................................ 2
Flow Diversions................................ 0
Inlets................................................ 0
Storage Nodes.................................. 1
Links.......................................................... 5
Channels.......................................... 0
Pipes................................................ 1
Pumps.............................................. 0
Orifices............................................. 2
Weirs................................................ 2
Outlets............................................. 0
Pollutants................................................. 0
LandUses................................................. 0
Rainfall Details
SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall
ID Source ID Type Units Period Depth Distribution
(years) (inches)
49 Time Series TS-100 Intensity inches North Carolina Union 100.00 7.50 SCS Type III 24-hr

Post-Development 100-Year Page 2
Subbasin Summary
SN Subbasin Area Peak Rate Weighted Total Total Total Peak Time of
ID Factor Curve Rainfall Runoff Runoff Runoff Concentration
Number Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 Sub-01 7.97 0.00 72.00 7.50 4.26 33.93 26.23 0 00:21:18
2 Sub-05 42.25 484.00 88.63 7.50 6.15 260.01 250.01 0 00:05:00

Post-Development 100-Year Page 3
Node Summary
SN Element Element Invert Ground/Rim Initial Surcharge Ponded Peak Max HGL Max Min Time of Total Total Time
ID Type Elevation (Max) Water Elevation Area Inflow Elevation Surcharge Freeboard Peak Flooded Flooded
Elevation Elevation Attained Depth Attained Flooding Volume
Attained Occurrence
(ft) (ft) (ft) (ft) (ft2) (cfs) (ft) (ft) (ft) (days hh:mm) (ac-in) (min)
1 CS Junction 570.00 578.50 0.00 9999.00 1.00 129.65 576.65 0.00 1.85 0 00:00 0.00 0.00
2 OUT-02 Outfall 569.00 151.88 572.50
3 OUT-SPILLWAY-02 Outfall 569.00 71.33 569.00
4 POND-05 Storage Node 570.00 580.00 574.50 1.00 248.74 579.48 0.00 0.00

Post-Development 100-Year Page 4
Link Summary
SN Element Element From To(Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow/ Peak Flow Peak Flow Peak Flow Total Time Reported
ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Design Flow Velocity Depth Depth/ Surcharged Condition
Node Elevation Elevation Ratio Total Depth
Ratio
(ft) (ft) (ft) N (in) (cfs) (cfs) (ft/sec) (ft) (min)
1 OUTLET-PIPE Pipe CS OUT-02 80.00 570.00 569.00 1.2500 42.000 0.0130 129.66 112.49 1.15 13.48 3.50 1.00 11.00 SURCHARGED
2 CS-RIM Orifice POND-05 CS 570.00 570.00 60.000 64.40
3 ORIFICE Orifice POND-05 CS 570.00 570.00 4.000 0.92
4 EMER-SPILLWAY Weir POND-05 OUT-SPILLWAY-02 570.00 569.00 71.33
5 WEIR Weir POND-05 CS 570.00 570.00 64.53

Post-Development 100-Year Page 5
Subbasin Hydrology
Subbasin:Sub-01
Input Data
Area(ac)............................................................................... 7.97
Peak Rate Factor.................................................................. 0
Weighted Curve Number...................................................... 72
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
7.97 72
Composite Area&Weighted CN 7.97 72
Time of Concentration
TOC Method:SCS TR-55
Sheet Flow Equation:
Tc=(0.007*((n*Lf)^O.8))/((P^O.5)*(Sf^O.4))
Where:
Tc=Time of Concentration(hr)
n =Manning's roughness
Lf=Flow Length(ft)
P =2 yr,24 hr Rainfall(inches)
Sf=Slope(ft/ft)
Shallow Concentrated Flow Equation
V =16.1345*(Sf^0.5)(unpaved surface)
V =20.3282*(Sf^0.5)(paved surface)
V =15.0*(Sf^0.5)(grassed waterway surface)
V =10.0*(Sf^0.5)(nearly bare&untilled surface)
V =9.0*(Sf^0.5)(cultivated straight rows surface)
V =7.0*(Sf^0.5)(short grass pasture surface)
V =5.0*(Sf^0.5)(woodland surface)
V =2.5*(Sf^0.5)(forest w/heavy litter surface)
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
Channel Flow Equation
V =(1.49*(R^(2/3))*(Sf^0.5))/n
R =Aq/Wp
Tc=(Lf/V)/(3600 sec/hr)
Where:
Tc=Time of Concentration(hr)
Lf=Flow Length(ft)
R =Hydraulic Radius(ft)
Aq=Flow Area(ft2)
Wp=Wetted Perimeter(ft)
V =Velocity(ft/sec)
Sf=Slope(ft/ft)
n =Manning's roughness

Post-Development 100-Year Page 6
Subarea Subarea Subarea
Sheet Flow Computations A B C
Manning's Roughness: 0.3 0 0
Flow Length(ft): 100 0 0
Slope(%): 1.89 0 0
2 yr,24 hr Rainfall(in): 3.5 0 0
Velocity(ft/sec): 0.1 0 0
Computed Flow Time(min): 16.69 0 0
Subarea Subarea Subarea
Shallow Concentrated Flow Computations A B C
Flow Length(ft): 615 0 0
Slope(%): 1.89 0 0
Surface Type: Unpaved Unpaved Unpaved
Velocity(ft/sec): 2.22 0 0
Computed Flow Time(min): 4.62 0 0
Total TOC(min)..................21.30
Subbasin Runoff Results
Total Rainfall(in).................................................................. 7.5
Total Runoff(in)................................................................... 4.26
Peak Runoff(cfs).................................................................. 26.23
Weighted Curve Number...................................................... 72
Time of Concentration(days hh:mm:ss)............................... 0 00:21:18

Post-Development 100-Year Page 7
Subbasin:Sub-01
Rainfall Intensity Graph
6.5
6
5.5
5
4.5
4
z
c 3.5
m
`c 3
2.5
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
28
27
26
25
24
23
22
21
20
19
18
17
N 16
`0 15
14
`o
� 13
(If 12
11
10
9
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 100-Year Page 8
Subbasin:Sub-05
Input Data
Area(ac)...............................................................................42.25
Peak Rate Factor.................................................................. 484
Weighted Curve Number...................................................... 88.63
RainGage ID.........................................................................
Composite Curve Number
32 Area Soil Curve
Soil/Surface Description (acres) Group Number
15.22 - 72
Paved parking&roofs 27.03 D 98
Composite Area&Weighted CN 42.25 88.63
Time of Concentration
User-Defined TOC override(minutes):5
Subbasin Runoff Results
Total Rainfall(in).................................................................. 7.5
Total Runoff(in)................................................................... 6.15
Peak Runoff(cfs).................................................................. 250.01
Weighted Curve Number...................................................... 88.63
Time of Concentration(days hh:mm:ss)............................... 0 00:05:00

Post-Development 100-Year Page 9
Subbasin:Sub-05
Rainfall Intensity Graph
7
6.5
6
5.5
5
4.5
z 4
c
m
3.5
`c
3
2.5
2
1.5
1
0.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)
Runoff Hydrograph
260
250
240
230
220
210
200
190
180
170
160
150
� 140
w 130
0
c 120
(If 110
100
90
80
70
60
50
40
30
20
10
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Time(hrs)

Post-Development 100-Year Page 10
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No.of
ID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate Barrels
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) N (in) (in) (cfs)
1 OUTLET-PIPE 80.00 570.00 0.00 569.00 0.00 1.00 1.2500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No 1

Post-Development 100-Year Page 11
Pipe Results
SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel Peak Flow Peak Flow Total Time Froude Reported
ID Flow Peak Flow Capacity Design Flow Velocity Time Depth Depth/ Surcharged Number Condition
Occurrence Ratio Total Depth
Ratio
(cfs) (days hh:mm) (cfs) (ft/sec) (min) (ft) (min)
1 OUTLET-PIPE 129.66 0 12:13 112.49 1.15 13.48 0.10 3.50 1.00 11.00 SURCHARGED

Post-Development 100-Year Page 12
Storage Nodes
Storage Node:POND-05
Input Data
Invert Elevation(ft)........................................................................ 570.00
Max(Rim)Elevation(ft).................................................................. 580.00
Max(Rim)Offset(ft)...................................................................... 10.00
Initial Water Elevation(ft).............................................................. 574.50
Initial Water Depth(ft)................................................................... 4.50
Ponded Area(ft2)............................................................................ 1.00
Evaporation Loss............................................................................ 0.00
Outflow Weirs
SN Element Weir Flap Crest Crest Length Weir Total Discharge
ID Type Gate Elevation Offset Height Coefficient
(ft) (ft) (ft) (ft)
1 EMER-SPILLWAY Trapezoidal No 578.50 8.50 20.00 1.50 3.33
2 WEIR Rectangular No 576.40 6.40 5.00 2.10 3.33
Outflow Orifices
SN Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice
ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient
Diameter Height Width Elevation
(in) (in) (in) (ft)
1 CS-RIM Bottom Rectangular No 60.00 60.00 578.50 0.63
2 ORIFICE Side CIRCULAR No 4.00 574.50 0.61
Output Summary Results
Peak Inflow(cfs)............................................................................. 248.74
Peak Lateral Inflow(cfs)................................................................. 248.74
Peak Outflow(cfs).......................................................................... 200.98
Peak Exfiltration Flow Rate(cfm).................................................... 0
Max HGL Elevation Attained(ft)..................................................... 579.48
Max HGL Depth Attained(ft).......................................................... 9.48
Average HGL Elevation Attained(ft)............................................... 576.15
Average HGL Depth Attained(ft).................................................... 6.15
Time of Max HGL Occurrence(days hh:mm)...................................0 12:13
Total Exfiltration Volume(1000-ft3)................................................ 0
Total Flooded Volume(ac-in).......................................................... 0
Total Time Flooded(min)................................................................0
Total Retention Time(sec).............................................................. 0

25-YR
CAPACITY

H EC-22
Energy Grade Line Computations
Struct. Q EGLo HGLo Total Pipe EGLi HGLi Ea EGLa Surface Elev.
ID (cfs) (ft) (ft) Loss (ft) (ft) (ft) (ft) (ft)
(ft)
18 578.86 578.86 576.04
17 52.8 579.03 578.86 0.06 579.09 578.92 7.4 579.13 581.01
16 52.4 579.19 579.03 0.10 579.30 579.13 6.5 579.44 582.78
34 51.9 579.50 579.34 0.05 579.56 579.39 6.0 579.64 583.56
33 43.1 579.71 579.53 0.09 579.80 579.62 5.5 579.87 584.44
32 41.5 579.94 579.77 0.09 580.03 579.86 5.1 580.071 585.50
52 1 41.41 580.14 579.97 0.12 580.26 580.09 4.7 580.40 588.10
108 1.5 583.47 583.301 0.18 583.66 583.49 0.8 583.81 588.00
29 38.7 580.50 580.25 0.08 580.58 580.33 4.7 580.64 587.24
28 39.0 580.83 580.36 0.51 581.33 580.86 4.9 581.71 585.21
27 33.3 581.85 581.50 0.09 581.94 581.59 5.0 582.02 585.21
26 30.6 582.14 581.85 0.31 582.45 582.16 4.8 582.56 583.91
25 19.91 582.81 582.19 585.81 583.75 3.1 585.81 592.95
24 12.7 585.91 585.65 0.11 586.02 585.77 2.6 586.12 592.95
23 9.6 586.30 585.84 589.89 588.31 2.4 589.89 594.90
22 6.9 589.99 589.75 595.58 593.96 2.2 595.58 600.04
21 5.6 595.71 595.38 601.08 599.61 2.1 601.08 603.69
20 4.5 601.17 600.96 603.50 602.651 1.5 603.501 607.54
131 2.91 603.53 603.451 607.28 606.61 1.2 607.28 616.98
133 1.0 607.28 607.27 609.54 609.16 0.7 609.54 610.34
73 3.8 585.86 585.72 593.16 591.85 1.8 593.16 597.02
118 2.1 593.18 593.13 594.25 593.31 1.3 594.25 597.41
62 4.8 582.66 582.42 0.94 583.60 583.36 3.3 583.70 586.66
61 2.8 583.74 583.65 0.29 584.02 583.94 1.4 584.09 589.63
60 0.81 584.10 584.09 585.49 585.21 0.6 585.49 592.60
64 2.8 582.59 582.52 583.60 582.66 1.4 583.60 587.38
63 1.2 583.61 583.59 586.24 585.65 0.9 586.24 589.82
105 3.2 581.75 581.65 585.18 584.24 1.4 585.18 589.44
104 1.5 585.19 585.17 585.96 585.29 1.0 585.96 589.43
96 1.1 580.40 580.25 0.14 580.54 580.391 0.7 580.66 584.44
76 9.01 579.69 579.56 0.06 579.75 579.62 5.7 579.81 583.34
120 8.8 579.86 579.73 0.13 579.99 579.87 4.6 580.03 581.79
75 4.9 580.07 579.96 0.33 580.40 580.28 2.8 580.46 583.31
74 1.4 580.47 580.46 581.93 581.58 0.7 581.93 586.22
129 578.86 578.86 1 574.33
79 48.71 579.09 578.86 0.14 579.23 579.00 6.6 579.33 582.08
78 48.4 579.48 579.09 0.40 579.88 579.49 4.9 580.04 583.59
77 48.0 580.19 579.81 0.14 580.33 579.94 4.5 580.43 584.20
128 47.2 580.70 580.01 0.33 581.04 580.34 4.7 581.54 584.00
127 46.2 581.80 581.14 0.34 582.15 581.48 4.8 582.70 589.95
50 46.4 582.97 582.30 585.10 582.311 4.3 585.10 591.11
41 44.11 585.34 584.731 589.78 587.07 4.2 589.78 594.91
39 11.6 589.86 589.65 595.85 593.63 2.9 595.85 597.95
38 8.5 596.00 595.63 603.43 601.50 2.6 603.43 606.29
37 5.8 603.50 603.33 608.86 607.28 2.1 608.86 613.20
36 3.1 608.90 608.80 616.38 614.97 1.8 616.38 620.06
35 1.4 616.38 616.36 618.28 617.39 1.2 618.28 621.60
114 1.41 608.87 608.85 0.02 608.89 608.87 2.0 608.91 613.61
113 1.4 603.44 603.42 0.02 603.46 603.44 2.3 603.47 605.61
112 1.4 595.86 595.84 0.02 595.88 595.86 2.3 595.89 598.23
49 11.6 589.86 589.65 0.29 590.15 589.94 3.6 590.31 592.42
48 10.7 590.39 590.20 0.08 590.47 590.28 3.5 590.56 592.42
47 7.4 590.60 590.51 0.06 590.66 590.57 3.1 590.71 594.46
46 5.61 590.77 590.62 595.34 594.00 1.9 595.34 598.19
45 4.0 595.37 595.29 600.55 599.44 1.6 600.55 605.05
44 2.6 600.57 600.53 605.74 604.86 1.3 605.74 611.95
E121 21.1 589.89 589.60 0.15 590.04 589.75 3.5 590.25 595.48
122 20.7 590.52 589.84 0.30 590.82 590.14 3.9 591.39 595.48
58 20.4 591.651 590.99 1.151 592.801 592.141 3.41 593.79 598.86
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Energy Grade Line Computations
Struct. Q EGLo HGLo Total Pipe EGLi HGLi Ea EGLa Surface Elev.
ID (cfs) (ft) (ft) Loss (ft) (ft) (ft) (ft) (ft)
(ft)
57 9.6 593.98 593.52 0.57 594.55 594.09 3.2 594.72 596.32
56 6.2 594.88 594.48 600.74 599.19 2.2 600.74 604.86
55 5.8 600.88 600.54 603.04 601.18 2.4 603.04 607.97
54 4.6 603.13 602.91 606.86 605.21 2.1 606.86 611.44
53 1.9 606.88 606.84 614.24 613.22 1.3 614.24 617.35
59 0.6 593.80 593.791 593.80 593.79 1.8 593.80 598.83
69 1 9.81 593.85 593.70 595.62 594.35 2.0 595.62 603.98
67 7.0 595.82 595.31 604.74 602.83 2.5 604.74 609.47
66 2.9 604.77 604.68 614.09 612.90 1.6 614.09 618.20
65 1.4 614.09 614.07 615.24 614.45 1.1 615.24 618.64
115 2.0 605.37 605.16 0.18 605.55 605.35 1.0 605.71 609.23
116 1.1 595.62 595.61 0.01 595.63 595.62 1.7 595.65 603.98
110 2.01 587.01 586.80 0.19 587.20 587.00 1.0 587.36 590.87
130 578.86 578.86 576.04
81 28.2 578.91 578.86 0.02 578.93 578.88 7.4 578.96 580.83
80 1.0 578.96 578.95 0.01 578.97 578.97 2.3 578.97 581.37
84 25.9 578.97 578.93 0.03 579.00 578.96 6.7 579.01 581.61
83 3.11 579.01 579.01 0.01 579.02 579.02 5.8 579.03 581.70
82 1.2 579.03 579.03 579.03 579.03 5.2 579.03 580.27
94 1.5 579.04 579.01 0.02 579.05 579.03 5.3 579.07 581.59
95 21.4 579.02 578.99 579.03 579.00 6.6 579.05 581.61
14 20.9 579.06 579.02 0.01 579.07 579.03 6.4 579.10 582.06
13 19.8 579.13 579.06 0.05 579.18 579.12 5.9 579.21 583.46
12 16.71 579.24 579.15 0.04 579.28 579.19 5.4 579.31 584.02
11 15.5 579.46 579.08 0.81 580.27 579.89 4.9 580.39 586.32
9 14.3 580.52 580.19 0.94 581.46 581.13 4.1 581.72 591.13
8 12.2 581.81 581.58 0.42 582.23 582.00 3.4 582.31 594.08
6 10.7 582.38 582.20 0.66 583.04 582.86 2.2 583.80 592.66
4 7.1 584.01 583.49 2.16 586.18 585.65 3.3 586.56 596.40
3 4.51 586.65 586.44 0.30 586.94 586.73 2.3 587.06 598.79
2 3.1 587.10 587.00 0.30 587.40 587.30 1.4 587.47 601.37
1 1.5 587.48 587.46 588.85 588.57 0.7 588.85 591.89
132 1.6 590.72 590.43 591.80 591.51 0.7 591.80 600.47
102 1.3 591.82 591.77 592.08 591.82 0.6 592.08 600.47
103 1.1 592.39 592.24 0.18 592.57 592.42 0.7 592.74 598.79
91 1 1.61 590.44 590.16 591.15 590.88 0.7 591.15 597.72
90 1.3 591.17 591.12 591.40 591.15 0.6 591.40 597.72
89 1.1 591.41 591.37 592.29 592.07 0.6 592.29 597.01
88 0.9 592.30 592.26 592.69 592.50 0.5 592.69 596.61
93 1.1 590.32 590.08 591.01 590.77 0.6 591.01 596.19
92 0.5 591.02 591.01 591.33 591.181 0.4 591.33 595.38
100 3.11 588.91 588.49 589.25 588.83 1.2 589.43 592.66
98 1.3 587.16 586.80 587.70 587.34 0.7 587.70 594.08
123 1.5 585.69 585.14 587.36 586.82 0.9 587.36 593.32
87 3.1 579.21 579.20 0.01 579.22 579.20 5.1 579.23 583.26
86 1.9 579.24 579.211 .06 579.31 579.27 3.6 579.32 580.18
15 0.5 579.101 579.101 579.10 579.10 5.11 579.11 582.08
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
17 18 84 0.251 0.55 9 6.16 52.8 52.8 54 181.3 11.40 9.881 571.71 571.00 0.85%
16 17 147 0.19 0.55 9 6.21 52.4 52.41 54 181.3 11.40 9.86 572.96 571.71 0.85%
34 16 77 0.22 0.55 9 6.24 51.9 51.9 54 181.3 11.40 9.83 573.62 572.96 0.85%
33 34 96 0.25 0.55 9 6.27 43.1 43.1 48 132.5 10.54 9.41 574.43 573.62 0.85%
32 33 109 0.15 0.55 9 6.32 41.5 41.5 48 101.7 8.09 7.67 574.97 574.43 0.50%
52 32 146 0.42 0.55 81 6.38 41.4 1 41.4 481 101.7 8.091 7.67 575.70 574.971 0.50%
108 52 37 0.371 0.55 5 7.031 1.5 1.5 15 4.6 3.73 3.31 583.00 582.82 0.50%
29 152 1 53 0.01 0.55 8 6.40 38.7 38.7 42 71.2 7.40 7.55 575.97 575.70 0.50%
28 29 147 0.81 0.55 8 6.47 39.0 39.0 36 51.3 7.26 7.98 576.84 575.97 0.59%
27 28 36 0.83 0.55 8 6.48 33.3 33.3 36 49.4 6.99 7.50 577.03 576.84 0.55%
26 27 147 1.00 0.55 7 6.55 30.6 30.6 36 47.2 6.67 7.10 577.77 577.03 0.50%
25 26 167 1.01 0.55 7 6.60 19.9 19.9 24 35.1 11.16 11.51 582.67 578.66 2.40%
24 25 36 0.86 0.55 7 6.61 12.7 12.7 241 35.1 11.16 10.25 583.53 582.67 2.40%
23 24 1 145 0.76 0.55 7 6.66 9.6 9.6 18 17.4 9.87 10.10 587.51 583.53 2.75%
22 23 164 0.34 0.55 7 6.71 6.9 6.9 18 19.9 11.24 10.20 593.35 587.51 3.57%
21 22 159 0.32 0.55 6 6.77 5.6 5.6 15 12.2 9.95 9.75 599.01 593.35 3.57%
20 21 151 0.44 0.55 6 6.83 4.5 4.5 15 9.1 7.45 7.41 602.03 599.011 2.00%
131 20 205 0.48 0.55 5 6.941 2.9 2.9 15 9.1 7.45 6.58 606.13 602.03 2.00%
133 131 137 0.26 0.55 5 7.03 1.0 1.0 15 9.2 7.47 4.92 608.88 606.13 2.01%
73 25 211 0.44 0.55 5 7.01 3.8 3.8 15 13.0 10.57 9.17 591.39 582.90 4.03%
118 73 39 0.54 0.55 5 7.03 2.1 2.1 15 13.0 10.57 7.77 592.97 591.39 4.03%
62 26 169 0.53 0.55 6 6.83 4.8 4.8 15 8.0 6.53 6.82 580.37 577.77 1.53%
61 62 149 0.52 0.55 6 6.91 2.8 2.8 15 8.0 6.53 5.96 582.65 580.371 1.53%
60 61 149 0.22 0.55 5 7.03 0.8 1 0.8 151 8.0 6.531 4.23 584.94 582.65 1.53%
64 26 112 0.40 0.55 5 6.98 2.8 2.8 15 11.6 9.45 7.76 582.25 578.66 3.22%
63 64 97 0.31 0.55 5 7.03 1.2 1.2 15 11.6 9.45 6.13 585.38 582.25 3.22%
105 28 207 0.45 0.55 5 7.01 3.2 3.2 15 11.1 9.02 7.80 583.78 577.72 2.93%
104 105 36 0.38 0.55 5 7.03 1.5 1.5 15 11.9 9.67 6.57 584.99 583.78 3.37%
96 33 28 0.29 0.55 5 7.03 1.1 1.1 15 4.6 3.73 3.08 579.97 579.831 0.50%
76 34 35 0.06 0.55 6 6.75 9.0 1 9.0 24 27.5 8.76 7.84 574.14 573.62 1.48%
120 76 88 1.06 0.55 6 6.79 8.8 8.8 24 27.5 8.76 7.80 575.44 574.14 1.48%
75 120 1 151 0.93 0.55 6 6.86 4.9 4.9 18 12.8 7.24 6.75 577.67 575.44 1.48%
74 75 242 0.35 0.55 5 7.03 1.4 1.4 18 12.8 7.24 4.72 581.25 577.67 1.48%
79 129 121 0.16 0.55 8 6.52 48.7 48.7 48 170.0 13.53 11.67 572.70 571.00 1.40%
78 79 172 0.17 0.55 7 6.57 48.4 1 48.4 42 119.1 12.38 11.73 575.10 572.70 1.40%
77 78 61 0.24 0.55 7 6.59 48.0 48.0 42 119.1 12.38 11.70 575.95 575.10 1.40%
128 77 67 0.30 0.55 7 6.61 47.2 47.2 36 78.9 11.17 11.66 576.88 575.95 1.40%
127 128 72 0.02 0.55 7 6.63 46.2 46.2 36 78.9 11.17 11.60 577.88 576.88 1.40%
50 127 145 0.21 0.55 71 6.67 46.4 46.4 36 95.2 13.471 13.38 580.84 577.88 2.03%
41 50 236 0.03 0.55 71 6.731 44.1 44.1 36 95.21 13.471 13.201 585.63 580.84 2.03%
39 41 188 0.47 0.55 6 6.84 11.6 11.6 24 44.7 14.22 11.95 592.94 585.63 3.89%
38 139 203 0.35 0.551 61 6.911 8.51 1 8.51 181 20.71 11.741 11.161 600.821 592.94 3.89%
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
37 38 1 152 0.351 0.55 51 6.96 5.8 5.8 18 20.7 11.741 10.07 606.74 600.82 3.89%
36 137 1 151 0.441 0.55 5 7.01 3.1 3.lj 15 14.7 12.01 9.50 614.58 606.74 5.19%
35 36 49 0.36 0.55 5 7.03 1.4 1.4 15 14.7 12.01 7.57 617.13 614.58 5.19%
114 37 35 0.37 0.55 5 7.03 1.4 1.4 15 4.6 3.73 3.30 606.92 606.74 0.50%
113 38 39 0.36 0.55 5 7.03 1.4 1.4 15 4.6 3.73 3.29 601.16 600.97 0.50%
112 39 38 0.37 0.55 5 7.03 1.4 1.4 15 4.6 3.73 3.29 593.64 593.451 0.50%
49 41 111 0.23 0.55 61 6.78 11.6 11.6 24 22.7 7.221 7.25 586.74 585.63 1.00%
48 149 1 36 0.88 0.55 6 6.79 10.7 10.7 24 22.7 7.22 7.12 587.11 586.74 1.00%
47 48 53 0.49 0.55 6 6.82 7.4 7.4 24 22.7 7.22 6.46 587.64 587.11 1.00%
46 47 181 0.43 0.55 6 6.89 5.6 5.6 18 18.8 10.64 9.29 593.43 587.64 3.20%
45 46 173 0.37 0.55 5 6.95 4.0 4.0 18 18.8 10.64 8.47 598.97 593.43 3.20%
44 45 172 0.68 0.55 5 7.03 2.6 2.6 18 18.8 10.64 7.51 604.48 598.97 3.20%
121 41 55 0.11 0.55 6 6.75 21.1 21.1 30 58.6 11.93 10.95 586.75 585.63 2.03%
122 121 36 0.12 0.55 6 6.76 20.7 20.7 24 32.3 10.28 10.91 587.49 586.75 2.03%
58 122 141 0.13 0.55 6 6.80 20.4 20.4 24 32.3 10.28 10.87 590.35 587.49 2.03%
57 58 68 0.91 0.55 6 6.85 9.6 9.6 18 13.8 7.81 8.44 591.52 590.35 1.72%
56 57 197 0.12 0.55 6 6.92 6.2 6.2 15 12.2 9.96 10.01 598.55 591.52 3.58%
55 56 43 0.31 0.55 5 6.93 5.8 5.8 15 14.1 11.53 10.94 600.62 598.56 4.79%
54 55 86 0.70 0.55 5 6.96 4.6 4.6 15 14.1 11.53 10.30 604.72 600.62 4.79%
53 54 171 0.50 0.55 5 7.03 1.9 1.91 15 14.1 11.53 8.08 612.91 604.72 4.79%
59 58 36 0.16 0.55 5 7.03 0.6 0.6 15 13.8 11.21 5.71 591.98 590.35 4.53%
69 58 160 0.48 0.55 6 6.86 9.8 9.8 24 32.3 10.28 9.02 593.59 590.35 2.03%
67 69 199 0.56 0.55 6 6.92 7.0 7.0 15 13.4 10.96 11.06 602.19 593.59 4.32%
66 67 239 0.38 0.55 5 7.01 2.9 2.9 15 13.4 10.96 8.73 612.51 602.19 4.32%
65 66 39 0.37 0.55 5 7.03 1.4 1 1.4 151 13.4 10.96 7.12 614.18 612.51 4.32%
115 67 37 0.52 0.55 5 7.03 2.0 2.0 15 4.6 3.73 3.61 604.76 604.58 0.50%
116 69 36 0.28 0.55 5 7.03 1.1 1.1 15 6.5 5.27 3.91 593.95 593.59 1.00%
110 50 39 0.52 0.55 5 7.03 2.0 2.0 15 4.6 3.73 3.62 586.41 586.22 0.50%
81 130 113 0.50 0.55 10 6.06 28.2 28.2 54 139.2 8.75 6.85 571.57 571.00 0.50%
80 81 125 0.26 0.55 5 7.03 1.0 1 1.0 18 21.2 12.01 6.20 576.66 571.57 4.07%
84 81 147 0.52 0.55 9 6.13 25.9 25.9 54 139.2 8.75 6.69 572.30 571.57 0.50%
83 84 185 0.13 0.55 6 6.88 3.1 3.1 30 29.0 5.91 3.87 573.23 572.30 0.50%
82 83 131 0.31 0.55 5 7.03 1.2 1.2 24 16.0 5.10 2.99 573.88 573.23 0.50%
94 83 30 0.39 0.55 5 7.03 1.5 1.5 15 4.6 3.73 3.35 573.79 573.64 0.50%
95 84 28 0.16 0.55 9 6.15 21.4 21.4 54 139.2 8.75 6.33 572.441 572.30 0.50%
14 95 44 0.25 0.55 9 6.171 20.9 20.91 48 101.71 8.09 6.36 572.66 572.44 0.50%
13 14 136 0.13 0.55 9 6.24 19.8 19.8 42 71.2 7.40 6.34 573.34 572.66 0.50%
12 13 57 0.38 0.55 9 6.27 16.7 16.7 36 64.1 9.07 7.62 573.86 573.34 0.92%
11 12 171 0.40 0.55 8 6.34 15.5 15.5 24 21.7 6.92 7.51 575.45 573.86 0.92%
9 11 234 0.25 0.55 8 6.45 14.3 14.3 24 21.7 6.92 7.39 577.60 575.45 0.92%
8 9 143 0.14 0.551 81 6.52 12.2 12.2 24 21.7 6.92 7.12 578.92 577.60 0.92%
6 8 292 0.22 0.55 7 6.66 10.7 1 10.71 241 21.71 6.921 6.901 581.61 578.92 0.92%
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
4 6 1 178 0.001 0.55 61 6.76 7.1 1 7.1 15 6.2 5.061 5.80 583.26 581.61 0.92%
3 14 1 62 0.091 0.55 6 6.79 4.5 4.5 15 10.2 8.33 8.05 584.80 583.26 2.50%
2 3 129 0.02 0.55 6 6.87 3.1 3.1 15 6.5 5.27 5.21 586.08 584.80 1.00%
1 2 208 0.38 0.55 5 7.03 1.5 1.5 15 6.5 5.27 4.26 588.17 586.08 1.00%
132 2 108 0.08 0.55 5 7.00 1.6 1.6 15 6.5 5.27 4.37 591.08 590.00 1.00%
102 132 36 0.33 0.55 5 7.03 1.3 1.3 15 6.5 5.27 4.12 591.44 591.081 1.00%
103 3 36 0.29 0.55 51 7.03 1.1 1.1 15 4.6 3.73 3.07 592.00 591.82 0.50%
91 14 1 78 0.09 0.55 6 6.86 1.6 1.6 15 6.2 5.02 4.21 590.44 589.73 0.91%
90 91 36 0.06 0.55 6 6.89 1.3 1.3 15 6.2 5.02 3.96 590.77 590.44 0.91%
89 90 105 0.05 0.55 5 6.98 1.1 1.1 15 6.2 5.02 3.75 591.72 590.77 0.91%
88 89 51 0.22 0.55 5 7.03 0.9 0.9 15 6.2 5.02 3.55 592.18 591.72 0.91%
93 4 69 0.15 0.55 5 6.98 1.1 1.1 15 6.5 5.27 3.93 590.42 589.73 1.00%
92 93 52 0.13 0.55 5 7.03 0.5 0.5 15 6.5 5.27 3.15 590.94 590.42 1.00%
100 6 1 34 0.80 0.55 5 7.03 3.1 3.1 151 6.5 5.27 5.21 588.22 587.88 1.00%
98 8 36 0.33 0.55 5 7.03 1.3 1.3 15 7.9 6.45 4.76 587.00 586.46 1.50%
123 9 67 0.38 0.55 5 7.03 1.5 1.5 15 10.2 8.33 5.921 586.49 584.82 2.50%
87 13 34 0.31 0.55 5 6.99 3.1 3.1 24 34.5 10.98 6.82 574.14 573.34 2.32%
86 87 69 0.50 0.55 5 7.03 1.9 1.9 15 9.8 8.03 6.24 575.74 574.14 2.32%
f15 14 25 0.12 0.55 5 7.03 0.5 0.5 15 4.6 3.73 2.38 574.001 573.881 0.507,
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

4 IN/HR
INLET
SPREAD

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
17 18 84 0.251 0.55 10 4.07 34.8 34.8 54 181.3 11.40 8.801 571.71 571.00 0.85%
16 17 147 0.19 0.55 10 4.07 34.3 34.31 54 181.3 11.40 8.76 572.96 571.71 0.85%
34 16 77 0.22 0.55 9 4.07 33.9 33.9 54 181.3 11.40 8.72 573.62 572.96 0.85%
33 34 96 0.25 0.55 9 4.07 27.9 27.9 48 132.5 10.54 8.35 574.43 573.62 0.85%
32 33 109 0.15 0.55 9 4.07 26.7 26.7 48 101.7 8.09 6.81 574.97 574.43 0.50%
52 32 146 0.42 0.55 91 4.07 26.4 1 26.4 481 101.7 8.091 6.79 575.70 574.97 0.50%
108 52 37 0.371 0.55 5 4.051 0.8 0.8 15 4.6 3.73 2.84 583.00 582.82 0.50%
29 152 1 53 0.01 0.55 8 4.07 24.6 24.6 42 71.2 7.40 6.72 575.97 575.70 0.50%
28 29 147 0.81 0.55 8 4.07 24.6 24.6 36 51.3 7.26 7.18 576.84 575.97 0.59%
27 28 36 0.83 0.55 8 4.07 20.9 20.9 36 49.4 6.99 6.69 577.03 576.84 0.55%
26 27 147 1.00 0.55 8 4.07 19.0 19.0 36 47.2 6.67 6.31 577.77 577.03 0.50%
25 26 167 1.01 0.55 7 4.07 12.3 12.3 24 35.1 11.16 10.17 582.67 578.66 2.40%
24 25 36 0.90 0.55 7 4.07 7.9 7.9 241 35.1 11.16 9.01 583.53 582.67 2.40%
23 24 1 138 0.68 0.55 7 4.07 5.9 5.9 18 17.1 9.68 8.77 587.18 583.53 2.65%
22 23 127 0.37 0.55 7 4.07 4.3 4.3 18 17.1 9.68 8.08 590.54 587.18 2.65%
21 22 175 0.37 0.55 6 4.07 3.5 3.5 15 10.5 8.58 7.71 595.18 590.541 2.65%
20 21 175 0.44 0.55 6 4.07 2.7 2.7 15 10.5 8.58 7.16 599.82 595.18 2.65%
131 20 209 0.48 0.55 5 4.071 1.7 1 1.7 15 10.5 8.58 6.27 605.37 599.82 2.65%
133 131 130 0.26 0.55 5 4.05 0.6 0.6 151 10.5 8.58 4.61 608.81 605.37 2.65%
73 25 1 211 0.44 0.55 5 4.07 2.1 2.1 15 13.0 10.57 7.77 591.39 582.90 4.03%
118 73 53 0.49 0.55 5 4.05 1.1 1.1 15 11.2 9.10 5.80 592.97 591.39 2.98%
62 26 169 0.53 0.55 6 4.07 2.9 2.9 15 8.0 6.53 5.98 580.37 577.77 1.53%
61 62 149 0.52 0.55 6 4.07 1.7 1.7 15 8.0 6.53 5.15 582.65 580.37 1.53%
60 61 149 0.22 0.55 5 4.05 0.5 1 0.5 15 8.0 6.53 3.60 584.94 582.65 1.53%
64 26 112 0.40 0.55 5 4.07 1.6 1.6 151 11.6 9.45 6.66 582.25 578.66 3.22%
63 64 1 97 0.31 0.55 5 4.05 0.7 0.7 15 11.6 9.45 5.21 585.38 582.25 3.22%
105 28 207 0.45 0.55 5 4.07 1.9 1.9 15 11.1 9.02 6.70 583.78 577.721 2.93%
104 105 36 0.38 0.55 5 4.05 0.8 0.8 15 11.9 9.67 5.59 584.99 583.78 3.37%
96 33 28 0.29 0.55 5 4.05 0.6 0.6 15 4.6 3.73 2.64 579.97 579.83 0.50%
76 34 35 0.06 0.55 7 4.07 5.4 5.4 24 27.5 8.76 6.81 574.14 573.62 1.48%
120 76 88 1.06 0.55 6 4.07 5.3 5.3 241 27.5 8.76 6.76 575.44 574.14 1.48%
75 120 1 151 0.93 0.55 6 4.07 2.9 2.9 18 12.8 7.24 5.85 577.67 575.44 1.48%
74 75 242 0.35 0.55 51 4.05 0.8 0.8 18 12.8 7.24 4.01 581.25 577.67 1.48%
79 129 121 0.16 0.55 8 4.07 30.7 30.7 48 170.0 13.53 10.25 572.70 571.00 1.40%
78 79 172 0.17 0.55 8 4.07 30.3 30.3 42 119.1 12.38 10.33 575.10 572.70 1.40%
77 78 61 0.24 0.55 8 4.07 29.9 29.9 42 119.11 12.38 10.29 575.95 575.10 1.40%
128 77 1 67 0.30 0.55 7 4.07 29.4 29.4 36 78.9 11.17 10.34 576.88 575.95 1.40%
127 128 72 0.02 0.55 71 4.07 28.7 28.7 36 78.9 11.17 10.27 577.88 576.88 1.40%
50 127 145 0.21 0.55 7 4.07 28.6 28.6 36 95.2 13.47 11.77 580.84 577.88 2.03%
41 50 236 0.03 0.55 7 4.07 27.0 27.0 36 95.2 13.47 11.58 585.63 580.84 2.03%
39 41 188 0.47 0.55 6 4.07 6.9 6.9 24 44.7 14.22 10.32 592.94 585.63 3.89%
38 39 2031 0.351 0.55 6 4.07 5.01 1 5.01 181 20.71 11.741 9.671 600.82 592.941 3.89%
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
37 38 1 152 0.351 0.55 51 4.07 3.4 1 3.4 18 20.7 11.741 8.66 606.74 600.82 3.89%
36 37 151 0.44 0.55 5 4.07 1.8 1.8 15 14.7 12.01 8.13 614.58 606.74 5.19%
35 36 49 0.36 0.55 5 4.05 0.8 0.8 15 14.7 12.01 6.43 617.13 614.58 5.19%
114 37 35 0.37 0.55 5 4.05 0.8 0.8 15 4.6 3.73 2.83 606.92 606.74 0.50%
113 38 39 0.36 0.55 5 4.05 0.8 0.8 15 4.6 3.73 2.82 601.16 600.97 0.50%
112 39 38 0.37 0.55 5 4.05 0.8 0.8 15 4.6 3.73 2.82 593.64 593.451 0.50%
49 41 111 0.23 0.55 6 4.07 6.9 6.9 24 22.7 7.22 6.34 586.74 585.63 1.00%
48 149 1 36 0.88 0.55 6 4.07 6.4 6.4 241 22.7 7.22 6.21 587.11 586.74 1.00%
47 48 53 0.49 0.55 6 4.07 4.4 4.4 24 22.7 7.22 5.60 587.64 587.11 1.00%
46 47 181 0.43 0.55 6 4.07 3.3 3.3 18 18.8 10.64 8.02 593.43 587.64 3.20%
45 46 173 0.37 0.55 5 4.07 2.4 2.4 18 18.8 10.64 7.27 598.97 593.43 3.20%
44 45 172 0.68 0.55 5 4.05 1.5 1.5 18 18.8 10.64 6.40 604.48 598.97 3.20%
121 41 55 0.11 0.551 7 4.07 13.0 1 13.0 30 58.6 11.93 9.59 586.75 585.63 2.03%
122 121 1 36 0.12 0.55 7 4.07 12.8 12.8 241 32.3 10.28 9.68 587.49 586.75 2.03%
58 122 141 0.13 0.55 6 4.07 12.5 12.5 24 32.3 10.28 9.62 590.35 587.49 2.03%
57 58 68 0.91 0.55 6 4.07 5.7 5.7 18 13.8 7.81 7.44 591.52 590.35 1.72%
56 57 197 0.12 0.55 6 4.07 3.7 3.7 15 12.2 9.96 8.70 598.55 591.52 3.58%
55 56 43 0.31 0.55 6 4.07 3.4 3.4 15 14.1 11.53 9.47 600.62 598.56 4.79%
54 55 86 0.70 0.55 5 4.07 2.7 1 2.7 15 14.1 11.53 8.87 604.72 600.62 4.79%
53 54 171 0.50 0.55 5 4.05 1.1 1.1 15 14.1 11.53 6.88 612.91 604.72 4.79%
59 58 36 0.16 0.55 5 4.05 0.4 0.4 15 13.8 11.21 4.84 591.98 590.35 4.53%
69 58 160 0.48 0.55 6 4.07 6.1 6.1 24 32.3 10.28 7.91 593.59 590.35 2.03%
67 69 199 0.56 0.55 6 4.07 4.1 4.1 15 13.4 10.96 9.63 602.19 593.59 4.32%
66 67 239 0.38 0.55 5 4.07 1.7 1.7 15 13.4 10.96 7.47 612.51 602.19 4.32%
65 66 39 0.37 0.55 5 4.05 0.8 1 0.8 15 13.4 10.96 6.05 614.18 612.51 4.32%
115 67 37 0.52 0.55 5 4.05 1.2 1.2 151 4.6 3.73 3.12 604.76 604.58 0.50%
116 69 36 0.41 0.55 5 4.05 0.9 0.9 15 6.5 5.27 3.74 593.95 593.59 1.00%
110 50 39 0.52 0.55 5 4.05 1.2 1.2 15 4.6 3.73 3.12 586.41 586.22 0.50%
81 130 113 0.50 0.55 10 4.07 18.9 18.9 54 139.2 8.75 6.11 571.57 571.001 0.50%
80 81 125 0.26 0.55 5 4.05 0.6 1 0.6 18 21.2 12.01 5.26 576.66 571.57 4.07%
84 81 1 147 0.52 0.55 10 4.07 17.2 17.2 541 139.2 8.75 5.94 572.30 571.57 0.50%
83 84 185 0.13 0.55 6 4.07 1.9 1.9 30 29.0 5.911 3.32 573.23 572.30 0.50%
82 83 131 0.31 0.55 5 4.05 0.7 0.7 24 16.0 5.10 2.54 573.88 573.23 0.50%
94 83 30 0.391 0.55 5 4.05 0.9 0.9 15 4.6 3.73 2.87 573.79 573.64 0.50%
95 84 28 0.16 0.55 10 4.071 14.1 14.1 54 139.2 8.75 5.62 572.44 572.30 0.50%
14 95 44 0.25 0.55 10 4.07 13.8 13.8 48 101.7 8.09 5.65 572.66 572.44 0.50%
13 14 1 136 0.13 0.55 9 4.07 12.9 12.9 42 71.2 7.40 5.62 573.34 572.66 0.50%
12 13 57 0.38 0.55 9 4.07 10.8 10.8 36 64.1 9.07 6.74 573.86 573.34 0.92%
11 12 171 0.40 0.55 9 4.07 10.0 10.0 24 21.7 6.92 6.76 575.45 573.86 0.92%
9 11 234 0.25 0.55 8 4.07 9.0 9.0 24 21.7 6.92 6.60 577.60 575.45 0.92%
8 9 1431 0.14 0.55 8 4.07 7.61 7.6 24 21.7 6.92 6.311 578.92 577.60 0.92%
6 8 2921 0.221 0.55 7 4.071 6.61 1 6.61 24 21.7 6.92 6.061 581.611 578.92 0.92%
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

H EC-22
Storm Drain Computations
Structure ID Length Drainage Runoff Tc Rain"I" Runoff Known Q Total Q Pipe Full Q Velocity Velocity Invert Elevation Slope
(ft) Area Coeff"C" (min) (in/hr) "Q" (cfs) (cfs) Dia. (cfs) Full Design
From To (ac) (cfs) (in) (ft/s) NO U/S D/S
4 6 1 178 0.001 0.55 71 4.07 4.3 1 4.3 15 6.2 5.06 5.45 583.26 581.61 0.92%
3 4 62 0.09 0.55 6 4.07 2.7 2.7 15 10.2 8.33 7.02 584.80 583.26 2.50%
2 3 129 0.02 0.55 6 4.07 1.8 1.8 15 6.5 5.27 4.53 586.08 584.80 1.00%
1 2 208 0.38 0.55 5 4.05 0.8 0.8 15 6.5 5.27 3.64 588.17 586.08 1.00%
132 2 108 0.08 0.55 5 4.07 0.9 0.9 15 6.5 5.27 3.75 591.08 590.00 1.00%
102 132 36 0.33 0.55 5 4.05 0.7 0.7 15 6.5 5.27 3.51 591.44 591.081 1.00%
103 3 36 0.29 0.55 5 4.05 0.6 0.6 15 4.6 3.73 2.63 592.00 591.82 0.50%
91 14 1 78 0.09 0.55 6 4.07 0.9 0.9 151 6.2 5.02 3.63 590.44 589.73 0.91%
90 91 36 0.06 0.55 6 4.07 0.8 0.8 15 6.2 5.02 3.40 590.77 590.44 0.91%
89 90 105 0.05 0.55 5 4.07 0.6 0.6 15 6.2 5.02 3.20 591.72 590.77 0.91%
88 89 51 0.22 0.55 5 4.05 0.5 0.5 15 6.2 5.02 3.02 592.18 591.72 0.91%
93 4 69 0.15 0.55 5 4.07 0.6 0.6 15 6.5 5.27 3.36 590.42 589.73 1.00%
92 93 52 0.13 0.551 5 4.05 0.3 0.3 15 6.5 5.27 2.68 590.94 590.42 1.00%
100 6 1 34 0.80 0.55 5 4.05 1.8 1.8 151 6.5 5.27 4.50 588.22 587.88 1.00%
98 8 36 0.33 0.55 5 4.05 0.8 0.8 15 7.9 6.45 4.06 587.00 586.46 1.50%
123 9 67 0.38 0.55 5 4.05 0.8 0.8 15 10.2 8.33 5.041 586.49 584.82 2.50%
87 13 34 0.31 0.55 5 4.07 1.8 1.8 24 34.5 10.98 5.811 574.14 573.34 2.32%
86 87 69 0.50 0.55 5 4.05 1.1 1.1 15 9.8 8.03 5.33 575.74 574.14 2.32%
15 14 25 0.12 0.55 5 4.05 0.3 0.3 15 4.6 3.73 2.02 574.00 573.88 0.50%
HTHOMAS s HUTTON T:IAutoC4DlReportslHEC-221HEC-22 Reporting

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 04
APPENDIX F
WATER QUALITY
CALCULATIONS
27842.0004
T
THOMAS & HUTTON

Water Quality Calculations
Cresswind-Wesley Chapel
Project No.27842.0003
WET POND 04
Project/Drainage Area: 42.25 Acres Required Water Quality Volume: 95,975 Cubic Feet
Impervious Area: I 27.03 Acres (Project Area(Acres)X 43,560 SF X 1''/12=Required Cubic Feet Volume)
64.0%Percent Impervious Runoff Coeifficient: R-05+0.9(I)= 0.63
(Required Collection of First 1''of Rainfall from the Project Site and Release over a Minimum 48 Hour(Maximum 120 Hours)in Cubic Feet Per Second)
Min.48-Hour Release Rate: 0.555 CFS Required Orifice Si— 4.00 Drawdown Time(Hours): 63.05
ater Quality Elevation Orifice Flow Calculation
Elev. Area Storage Q-CdA*sgrt(2gh)
(ft) (sf) (cu.ft) Cd= 0.62 (Sharp Orifice)
NWL 574.50 46,123.00 0.00 A= 0.087 sf
TOP OF BERM 580.00 69,643.00 318,356.50 g= 32.174 ft/s,
Elevation Pond Depth Storage h= 1.90 ft
(ft) (ft) (cu.ft) Q= 0.423 cfs
576.40 2.40 95,975.00 Colculotedfrom Stage-Storage Table
VPP—Vshelf
D" Abottomofshelf
nere. = T-I me or perm�ehehr pool(reer)
only(leap)—aee below
Average Depth Calculation �a,•=„ Area or wa�a woe�e�ne mhem rn,he aherc(ree��
Vpp Designed @ Elevation 1574.50 136,114.00 ,„.„= o.s^oePth„„„„„,„^Pehreerer,•„„„„^Width.,„„,.„.„­
Permanent Pool SA Designed @ Elev 1574.50 37,629.00 here. o—„„„, = Depth orwa�-th1deepelaeortheebelras
brae ar vermarcem vohl Deep
Area of wet pond at the bottom ofthe shelf 34,219.00 aerlmerer,.m....�,�o� = aaame er or vermahem ve°i ar me eonom or ma
Dmax over shelf 0.50 width fr-tha aeav s�aem ma a.y aide erma
sM1elf as measuratl al peananent pool(fiat)
Perimeter of Permanent Pool 1,141.00
Width of submerged part of shelf 3.00
Volume over the shelf only 855.75 _ �e reo�=� oe�=�� „me wa„Pees nem u.;eeen,tsael
Average Depth 1 3.95 1 .
SA/DA Method - - -
Drainage Area 42.25 acres o ,
Table value 1.75
Surface Area Required 32,207.18 Isquare feet

Stage Storage Calculations
Cresswind-Wesley Chapel
Project No. 27842.0002
WET POND 05
FOREBAY 01 VOLUME
CONTOUR CONTOUR INC.VOL. CUM.VOL.AVG.
ELEV AREA(SF) DEPTH (FT) AVG. END END(CU. FT.)
570 4,201 N/A N/A 0
571 4,846 1 4,523 4,523
572 5,535 1 5,191 9,714
573 6,268 1 5,902 15,615
574 7,045 1 6,657 22,272
574.5 8,096 0.5 3,785 26,058
TOTAL FOREBAY VOLUME:1 26,058 CU.FT
PERCENTAGE OF PERMANENT POOL VOLUME:1 19%
PERMANENT POOL VOLUME
CONTOUR CONTOUR DEPTH (FT) INC.VOL. CUM.VOL.AVG.
ELEV AREA(SF) AVG. END END(CU. FT.)
570 24,933 N/A N/A 0
571 27,208 1 26,071 26,071
572 29,515 1 28,362 54,432
573 31,852 1 30,683 85,115
574 34,219 1 33,036 118,151
574.5 37,629 0.5 17,962 136,114
PERMANENT POOL VOLUME:I 136,114 CU.FT
TEMPORARY PONDING ZONE
CONTOUR CONTOUR DEPTH (FT) INC.VOL. CUM.VOL.AVG.
ELEV AREA(SF) AVG. END END(CU. FT.)
574.5 46,123 N/A N/A 0
575 49,902 0.5 24,006 24,006
576 53,737 1 51,819 75,825
577 57,629 1 55,683 131,508
578 61,577 1 59,603 191,111
579 65,582 1 63,579 254,690
580 69,643 1 67,613 322,303
TEMPORARY PONDING ZONE VOLUME:1 322,303 CU. FT.

Cresswind Wesley Chapel-Phase 04 Job: J-27842.0004
KH Wesley Chapel,LLC Date: 4/16/23
Thomas&Hutton Engineering Co. Revised:
nlfeac+
Anti-Flotation Design Considerations By: MSK
ANTI-FLOTATION DESIGN CONSIDERATIONS FOR:
Wet Pond 05
CONTROL STUCTURE ELEVATIONS
Top Structure Elevation: 578.50
Bottom Structure Elevation: 570.00
CONTROL STRUCTURE FLOTATION
Buoyant Force
Calculate submerged volume:
V,= (A.,x H,j
Where:
V,= Submerged volume(cf)
Leg= Length of control structure(ft) = 8.50 ft
Wig= Width of Control structure(ft) = 5.00 ft
Aug- Cross-sectional area of control structure(ft) = 42.50 ft
Hag= Height of control structure(ft) = 8.50 ft
Solve equation for V,:
V,= (A.,x H,j = 361.25 cf
Calculate buoyant force:
Fb= Vg x Ywalu
Where:
Fb= buoyant force(lbf)
y,= Specific weight of water = 62.40 lbf/cf
Fb= 22,542 lbf
Z:A27842\27842.0004\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0004-Wet Pond 05-Anti Flotation
Design Calculations-updated Page 1 of 3

Cresswind Wesley Chapel-Phase 04 Job: J-27842.0004
KH Wesley Chapel,LLC Date: 4/16/23
Thomas&Hutton Engineering Co. Revised:
nlfea�c+
Anti-Flotation Design Considerations By: MSK
Downward Force
Calculate Downward Force of Control Structure
Fdcs= (Vcs-Vwcir-Vorifice)x yconcrete
Where:
WtC3= Weight of control structure(lbs)
Yconcrete= Specific weight of concrete = 140.00 lbf/cf
Acs= Cross-sectional area of control structure(ft) = 42.50 ft
Hcs= Height of control structure(ft) = 8.50 ft
Tcs= Wall thickness of control structure(ft) = 0.50 ft
Vcs= Volume of control structure(cf) = 106.25 cf
Wweir= Width of weir(ft) = 5.00 ft
HWeir= Height of weir opening(ft) = 2.10 ft
AWeir= Area of weir opening(ft) = 10.50 sf
VWeir= Volume of weir = 5.25 cf
DIAorifice= Diameter of orifice opening(in) = 4.00 in
Aorifice= Area of orifice opening(sf) = 0.087 sf
Vorifice= Volume of orifice opening(sf) = 0.044 cf
FdC3= 14,134 lbf
Size Anti-Flotation Footing to Resist BoUant Force
FdC3+Fda>Fb
Fdft—(Lb X Wb X Db)X 7concrete
Where:
Fdcs= downward force of control structure(lbf) = 14134 lbf
Fb= buoyant force(lbf) = 22542 lbf
Yconcrete= Specific weight of concrete = 77.60 lbf/cf
Lb= Length of Concrete Block = 15.00 ft
Wb= Width of Concrete Block = 15.00 ft
Db= Depth of Concrete Block = 12.00 in
Fdit= downward force of anti-flotation footing(lbf) = 17460 lbf
Z:A27842\27842.0004\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0004-Wet Pond 05-Anti Flotation
Design Calculations-updated Page 2 of 3

Cresswind Wesley Chapel-Phase 04 Job: J-27842.0004
KH Wesley Chapel,LLC Date: 4/16/23
Thomas&Hutton Engineering Co. Revised:
nlfea�c+
Anti-Flotation Design Considerations By: MSK
Fd,s+ Fd,= 31594 lbf>Fb= 22542 lbf _
Factor of Safety
Confirm anti-flotation block is sized for minimum factor of safely((F j of 1.10.
F, = (Fd.+Fdft)/Fb
1.40 > 1.10
Z:A27842\27842.0004\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0004-Wet Pond 05-Anti Flotation
Design Calculations-updated Page 3 of 3