SW3210301_Design Calculations (Stormwater - Phase 2)_20211118

Iq
STORMWATER MANAGEMENT REPORT
FOR:
CRESSWIND WESLEY CHAPEL - PHASE 02
WESLEY CHAPEL.. NC
PREPARED FOR:
KH WESLEY CHAPEL, LLC
IclIJAI
N
� .aFE6SlON .. 9 ��
J � •. �/ ��
THOMAS
& =
HUTTON
049480 =
_ ENGINEERING
�—I�-ak
��•.. No. F-0871
T FNGINEEP.•�� ��
�,ii'%nic '•..........•''•�\tip`����
OF
J - #2 7842.0002
FEBRUARY 16, 2021
LATEST REVISION: SEPTEMBER 16,2021
Prepared by:
THOMAS Sc HUTTON

STORMWATER MANAGEMENT REPORT
Cresswind Wesley Chapel - Phase 02
Project: Cresswind Wesley Chapel - Phase 02
T&H Job Number: J-27842.0002
Location: Potter Road
Wesley Chapel, NC 28173
Date Prepared: February 16, 2021
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
AerialLocation 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
Summary of Results - Existing Conditions
Storm Event
Outfall 01
Outfall 02
Combined
(cfs)
(cfs)
(cfs)
2-year
66
14
80
10-Year
134
31
165
25-Year
173
41
214
50-Year
208
51
259
Table 2- Post Development Runoff Rates
TABLE 1
Summary of Results - Proposed Conditions
Storm Event
Outfall 01
Outfall 02
Combined
(cfs)
(cfs)
(cfs)
2-year
60
9
69
10-Year
124
19
148
25-Year
170
25
197
50-Year
183
31
215
H THOMAS & HUTTON
Page 3

SECTION 2 - PROJECT NARRATIVE
Cresswind is a residential subdivision within Wesley Chapel, North Carolina. Phase 2 consists of
approximately 76 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 3 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 basins 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 and 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.
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 as the site plan evolves 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 85% 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 N RCS (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.
Curve Numbers
H THOMAS & HUTTON
Page 6

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)
_ 0.007(nL)48
t1 — P2 0.05 X S
0.4
Shallow Concentrated Flow: (hr)
L
_
tZ 3600 X V
Channel Flow: (hr)
L
_
t3 3600 X V
Time of Concentration: (hr)
t, = t1 + tZ + t3
Symbol
Dimension
Units
n
Manning's n
--
L
Length of flow
ft
P2
2 yr event
rainfall
in
S
Slope
ft/ft
Symbol
Dimension
Units
L
Length of flow
ft
V*
Velocity
ft/s
*Based on TR-55 velocity -slope relationship
Symbol
Dimension
Units
L
Length of flow
ft
V*
Velocity
ft/s
*Assumed to be 2 ft/s
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 81 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 " and Outfall "02" discharge 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 82 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 76 single family lots in Phase 2 and 96 lots
in a future phase, 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
3 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, fifty (50) year and one hundred (100) 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, fifty
(50) and one hundred (100) year storm events.
H THOMAS & HUTTON

Table 3 - Wet Detention Pond 03
Bottom of Pond = 559.00
Crest of Emergency Spillway = 571.00
Top of Embankment = 571.50
Wet Detention Pond 03
Storm Event
Max Elevation
(ft)
10-Year
568.88
25-Year
569.25
50-Year
569.68
100-Year
570.05
H THOMAS & HUTTON
Page 9

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 02
APPENDIX A
PROJECT MAPPING
27842.0002
Fq THOMAS Sc HUTTON

This map was created using geothinQ I www.geothinQ.com I Mapping Smart Land Decisions

This map was created using geothinQ I www.geothinQ.com I Mapping Smart Land Decisions

This map was created using geothinQ I www.geothinQ.com I Mapping Smart Land Decisions

MAS
�� �� I � HUOTTON
%REd)vF 141- FL, I -LFll
x
AE
El
This map was created using geothinQ I www.geothinQ.com I Mapping Smart Land Decisions
27842 Cresswind
Phase 02
Soils
02/16/2021
1%Annual Chance Flood Hazard
Regulatory Floodway
Special Floodway
Area of Undetermined Flood Hazard
0.2%Annual Chance Flood Hazard
i9 Future Conditions 1%Annual Chance
Flood Hazard
... e Area with Reduced Risk Due to
Levee
Area of Minimal Flood Hazard

a
529300
34o 59' 31" N
r
�i
g
N
r
�i
r
�i
M
n
�i
n
�i
g
r
n
�i
ai
n
�i
n
�i
n
�i
34o 59' 0" N
Hydrologic Soil Group —Union County, North Carolina
529400 529500 529600 529700 529800 529900 530000 530100 530200 530a)D 53NW 530500
529300 529400 529500 529600 529700 529800 529900 530000 530100
in
Map Scale: 1:6,760 if printed on A landscape (11" x 8.5") sheet.
Meters
$ N 0 100 200 400 600
Feet
0 300 600 1200 1800
Map projection: Web Mercator Conermordinates: WGS84 Edge tics: UTM Zone 17N WGS84
USDA Natural Resources Web Soil Survey
40111111 Conservation Service National Cooperative Soil Survey
a
m
530600 5W700
34o 59' 31" N
r
�i
g
N
r
�i
r
�i
M
n
�i
n
�i
g
r
n
�i
tb
n
�i
n
�i
n
�i
�i
34o 59' 0" N
530200 530300 530400 530500 530600 530700
a
m
2/17/2021
Pagel of 4

Hydrologic Soil Group —Union County, North Carolina
MAP LEGEND
Area of Interest (AOI)
0
Area of Interest (AOI)
Soils
Soil Rating
Polygons
0
A
0
A/D
0
B
0
B/D
C
0
C/D
0
D
0
Not rated or not available
Soil Rating
Lines
r 0
A
r 0
A/D
B
B/D
N 0
C
r 0
C/D
r 0
D
r 0
Not rated or not available
Soil Rating
Points
0
A
0
A/D
0
B
0
B/D
❑ C
0 C/D
0 D
❑ Not rated or not available
Water Features
Streams and Canals
Transportation
— Rails
­0 Interstate Highways
US Routes
Major Roads
Local Roads
Background
D6 Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 20, Jun 3, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jul 18, 2011—Oct 30,
2018
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
usoA Natural Resources Web Soil Survey 2/17/2021
Conservation Service National Cooperative Soil Survey Page 2 of 4

Hydrologic Soil Group —Union County, North Carolina
Hydrologic Soil Group
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
2mx85
Badin channery silty
C
52.7
65.2%
clay loam, 2 to 8
percent slopes,
moderately eroded
2mx8q
Tarrus gravelly silty clay
B
3.1
3.9%
loam, 2 to 8 percent
slopes, moderately
eroded
3wOp
Chewacla silt loam, 0 to
B/D
14.3
17.7%
2 percent slopes,
frequently flooded
3w12
Goldston-Badin
D
10.7
13.2%
complex, 8 to 15
percent slopes
Totals for Area of Interest
80.9
100.0%
USDA Natural Resources Web Soil Survey 2/17/2021
Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group —Union County, North Carolina
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 2/17/2021
Conservation Service National Cooperative Soil Survey Page 4 of 4

National Flood Hazard Layer FIRMette
O FEMA
Legend
34°59'33.10"N
0 250 500 1,000 1,500 2,000
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
Without Base Flood Elevation (BFE)
Zone A, V, A99
SPECIAL FLOOD With BFE or Depth Zone AE, AD, AH, VE, AR
HAZARD AREAS Regulatory Floodway
0.2%Annual Chance Flood Hazard, Areas
of 1%annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile zone x
wI Future Conditions 1%Annual
Chance Flood Hazard zone x
pr Area with Reduced Flood Risk due to
ITHER AREAS OF Levee. See Notes. zone x
FLOOD HAZARD FA d' Area with Flood Risk due to Leveezono D
NO SCREEN Area of Minimal Flood Hazard zone x
Q Effective LOMRs
OTHER AREAS Area of Undetermined Flood Hazard zone D
GENERAL ---- Channel, Culvert, or Storm Sewer
STRUCTURES IIIIIII Levee, Dike, or Floodwall
e xo.s Cross Sections with 1%Annual Chance
17•5 Water Surface Elevation
o- — — Coastal Transect
—513— Base Flood Elevation Line (BFE)
Limit of Study
Jurisdiction Boundary
-- --- Coastal Transect Baseline
OTHER _ Profile Baseline
FEATURES Hydrographic Feature
Digital Data Available N
No Digital Data Available
MAP PANELS ® Unmapped
9 The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 12/9/2019 at 2:06:16 PM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 02
APPENDIX B
PRE -DEVELOPMENT DRAINAGE MAP
27842.0002
Fq THOMAS Sc HUTTON

a
Q
\
HIV
Ui
MIN
■
51
hl\\ ( >
PHASE I
OUTFALL 03
PHASE I -DEVELOPMENT
BASIN
SUB-03
CN: 67
AREA: 2 AC-
��'� �—
y
Tc: 5 MIN
I
ji
PHASE I -DEVELOPMENT
BASIN
\\\ �1�,//i jjll SUB-04
�\ J CN: 73
AREA: 2.1 AC.
Tc: 5 MIN
OUTFALL 05 —
•�'�� \\\�_��`�i �� �\`�1) //l
(//1(1
)� 1 /(� ( Jst�(I(tll / / / /
v;—�` l�
..�. � = VA\/������vVAVA\\\�J /■/ / 7 J I((I I � 11 1
/ 1��'/
— 5 7 5 i -� 1 \ l / 1 / C n`' I < 1 / I / / .r � \ I / � 1, \ . ✓� ^ ^\�\��J 1 J I
r �11 IIII\\��// / / /II)I1JI \ \\)1I 1\\�\Iti S I
\�\\� w(I
-�� -_ \ � \ )) I \ L �-- ; � J // / � / � � /i ✓ � { IIII \
`�:� ,-��\�1/1111111��1 / Il/l / %—��S I I�\\ //i.�I ,,J^r //, N �r// /r I I / � 1 1\L�}I \�f i'_��S�L�✓`a `•1�� .=:/
m .,r_ % (%� n� I \
� � �- / / 1
••� 1/ (l// �l l l I I )� l l 1 I l J/ l 11) ! J � r /' r � _
J
/ice,, s � \ •���� �� ,� /
............:
0
,,, = ' ;/ / �"� • ,.;:�'''� •l Ill (� / � (
�� 1' �.-`�- - - -�_•= - '; � -ill/S1/ /%i%a� �:. .•���`���\I C � V�� 1�.•
PHASE
/ - • /l T r (I I ��All��l A Q PHASE
OJTFALU 02
OUTFALL 02`
�iJi J I 1 1 15 11 I o ::.•
:;�
�•��::.: _ ,, ', � , ' i \ �n / // _ �� "^ y ::•:
,r II- =�
-1VI
�•�,•-:•.•-.;;: - /�%// � - , \ �\1 � �k / }r�, - — � — - \. -\ I J / �,� ;� �\ l l � IIIIIII I I
' ` „i � IIIIIjIII IIIIIIIIII I % - � f
// �vv�v - ,1 �11111� PHASE DEVELOPMENT v� v�;'I IIIIIIII IJ 1 ���
/j/i1/i ��\�\ BASIN
s u B o I
AREA: 10-62 AC- I � //j// / � 'v �::• ( \�
84
Tc: 5 MIN-
�f
1�yJ(
• 3� � �'Yl (I � I l I I / ,_ \ ��� � \ � I , _ � �
.,
PHASE
'II+Ilflf \, ) \� ��\� \ate �L� r c I BASIN
-�°�w'II Illllj(�j� �I I /l v v� w� �� �'��v/� /
tI (1II111= �11
II�� wv= v-� t� SUB-02
�: rL CN: 82
J
''• � �I � � III I I \ 590— Illl 11 A �— �������. / -�� =��� .'� AREA: 57.34 AC-
`'•:II11�� Tc: 5 MIN \�.•
•:�::= 1 � �IIItZlllllllllll I vl� v� — � ���� - - - - - - - -� _•.. � / � -- � / ��
a"I
\ ),IIIIIlIl1\VII\1AVAI\v\1 = v > /- - - - - - -
1 IS�I� 1\\ _�� I r �� - - - - --
/ 1\sw
\\ �\ I------------ -
,�yII�
•:.,�� •<;: � - �-•�7c, L`fl/iJ//I FLOW
LI OW �PATH
- '- /• .(rs'-�="- VA\ \-�- - -- -- -_ ' I ��\�� \ �n� � ,1� � /
�� �1 ���� •F:`' \���-�I•• �� - - - ����� � �- � �� /
_ Y \ PRE -DEVELOPMENT BASIN
l�
- - I (IIIII// / ( /� _� �� \ ) N 1 �~ \ \ SUB-02
v- - - TbB2
C IN: 72
AREA: 17.12 AC.
/ /i i \ _I_ _ ) •% //. \\\\ / 1�, �\ ��
n _ 1 Tc: 35
ChA
: • - - :::' J -�1�T- J- ✓--< d- ram-- I 5r�_ - -- -- - -Qtrl 1 PHASE
L CUTEALL 06
F_. .:
;
_ _ _ _ ___ _ _ `�- ,�;�li�// //(f/ S�>/� �5/s/�i///l/ \ �/ \\\\� , �� �F ��^�V /%////%/• /�IIU f' :...,
FLOW PATH - - - - -1 - S- - �rjl j �j//i/��///i ii�� } ° // /j / \ \\ so \ \ /%%/ / / N:
� // -` �- � � \\ `O � � \ � �D//// / l / I l/ ��- ,,,�• •.r
::•:��-��I,.: -_ -_ {_ -- _ _v(1
:•• � OUTFALL 01 ����. -1 ��_�{I-°�_-_-C�. I /////ice /�i� �////////l///� /-_'� ���� ���=>>//l J I// ( o \\�� A 1 i lip � I � ���w��v / f= � �� •- .- � i, / �� ,�,
/� C _
��_-�fi��-_-_-(Ij'
'�•`• ��� = • l - - `� - �- - - ° � - -� � i 'u'I�l I � � � I) (\ \ \ � � -� % : = ; -� 11 I 1 \ s � � \ \ � c 1 l l � ) I � \��� , / ���. - _. � �
-�l - -- -o- � ll(11111 Iflllll�( (( / I �\ ��\\ \ \ ? )( I \ �� i;
V\
kh,
Y Wlssw PRE -DEVELOPMENT BASIN
SUB-01
---�-_-_-_-_ _t>_-�-�- _ �•. �����1�\� ���V\II(� \VVA�\v //i////llll (\—v � 1 I ,/ �s�-�' � V Av\� � \IIIII \11 I ((� \ A v v ��- � \\ ��� ���� / r
- - - - C- - -S�� CN: 76
.
.. �.. - - - - - 1- - >- - � r ���\\� ���\\�Z��� _ AREA: 63.74 AC.
�������� )>��� = Tc: 36`RG
•��- - - - -_ _�11 hI ((��`���� �����-��///%//(l/ /IIIIIII 1 �) l ///i%�/���// / l �///� /�/ 1 I \IA \t\ v � ��/�c,__��\1v���� '` `'��� �
Illll
• ��---_ _ _ _ ��l(ISSI )\11A11`�1 �-���__ � v�\(
- ���- - _ - - - �✓ - - �lI:J l/�//�/ jr/� >/Jcj, iJ
..:`:•:: 54�r�v 54s- - �J- �lll v\\/%l le�� / (l l / l/ j////�/ �����, i 1 \ �� — v
\ a
PHASE I
/ / / o
I
I �
�„ f J Jul f 1 i � � � � � � � / �/ I • .
PHASE I
OUTFALL 04
10
w
S
E
PRE -DEVELOPMENT
DRAINAGE EXHIBIT
CRESSWIND PHASE 2
MONROE, NC
PREPARED FOR:
KH WESLEY CHAPEL, LLC
PREPARED BY:
ate.
T THOMAS
~ — H HUTTON
1020 Euclid Avenue
Charlotte, NC 28202 • 980.201.5505
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 02
APPENDIX C
PRE -DEVELOPMENT CONDITIONS
DRAINAGE CALCULATIONS
27842.0002
Fq THOMAS Sc HUTTON

277842.0002
CRESSWIND WESLEY CHAPEL - PHASE 02
PRE -DEVELOPMENT BASINS MODEL

Pre -Development 002 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Pre Development.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 --------------------------------------
15
seconds
Number of Elements
Qty
Rain Gages
1
Subbasins
2
Nodes
2
Junctions
0
Outfalls
2
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
ID Factor Curve
Number
Total Total Total Peak Time of
Rainfall Runoff Runoff Runoff Concentration
Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 SUB-01 63.74 484.00 75.96 3.50 1.36 86.88 65.63 0 00-36-13
2 SUB-02 17.12 484.00 71.63 3.50 1.10 18.84 13.90 0 00-35-02

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
540.00
0.00 0.00
2 Out-02 Outfall
556.00
0.00 0.00

Pre -Development 002 - Year
Subbasin Hydrology
Page 4
Subbasin : SUB-01
Input Data
Area(ac)------------------------------------------------------------------------
63-74
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
75-96
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Woods, Fair
14-32
D
79-00
Woods, Fair
10-68
D
79-00
Pasture, grassland, or range, Good
38-74
C
74-00
Composite Area & Weighted CN
63-74
75-96
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness

Pre -Development 002 - Year Page 5
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-23
Subbasin Runoff Results
Flowpath
Flowpath Flowpath
A
B
C
0-4
0-00
0-00
100
0-00
0-00
1
0-00
0-00
3-50
0-00
0-00
0-06
0-00
0-00
27-09
0-00
0-00
Flowpath
Flowpath
Flowpath
A
B
C
1771
0-00
0-00
4
0-00
0-00
Unpaved
Unpaved
Unpaved
323
0-00
0-00
9-14
0-00
0-00
Total Rainfall (in)------------------------------------------------------------ 3-50
Total Runoff (in)------------------------------------------------------------- 1-36
Peak Runoff (cfs)----------------------------------------------------------- 65-63
Weighted Curve Number----------------------------------------------- 75-96
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-14

Pre -Development 002 - Year Page 6
Subbasin : SUB-01
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
Rainfall Intensity Graph
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
75
70
65
60
55
50
45
40
0
� 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
Subbasin : SUB-02
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 17-12
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 71-63
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
14-00
C
74-00
Pasture, grassland, or range, Good
3-12
B
61-00
Composite Area & Weighted CN
17-12
71-63
Time of Concentration
Flowpath
Flowpath Flowpath
Sheet Flow Computations
A
B C
Manning's Roughness :
-4
0-00 0-00
Flow Length (ft) :
100
0-00 0-00
Slope (%) :
1-11
0-00 0-00
2 yr, 24 hr Rainfall (in) :
3-50
0-00 0-00
Velocity (ft/sec) :
0-06
0-00 0-00
Computed Flow Time (min) :
25-99
0-00 0-00
Flowpath
Flowpath Flowpath
Shallow Concentrated Flow Computations
A
B C
Flow Length (ft) :
1531-55
0-00 0-00
Slope (%) :
3-06
0-00 0-00
Surface Type:
Unpaved
Unpaved Unpaved
Velocity (ft/sec) :
2-82
0-00 0-00
Computed Flow Time (min) :
9-05
0-00 0-00
Total TOC (min)------------------35-04
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 3-50
Total Runoff (in)------------------------------------------------------------- 1-10
Peak Runoff (cfs)----------------------------------------------------------- 13-90
Weighted Curve Number----------------------------------------------- 71-63
Time of Concentration (days hh:mm:ss)------------------------ 0 00-35-02

Pre -Development 002 - Year Page 8
Subbasin : SUB-02
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
14.6
14
135
13
12.6
12
11.6
11
105
10
9.5
9
8.6
8
75
0 7
6.6
6
5.6
5
45
4
3.5
3
2.6
2
15
0.5
Rainfall Intensity Graph
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
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 1
Project Description
File Name .................................................... 27842.0002 - Pre Development.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 --------------------------------------
15
seconds
Number of Elements
Qty
Rain Gages
1
Subbasins
2
Nodes
2
Junctions
0
Outfalls
2
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
ID Factor Curve
Number
Total Total Total Peak Time of
Rainfall Runoff Runoff Runoff Concentration
Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 SUB-01 63.74 484.00 75.96 520 2.70 171.97 134.44 0 00-36-13
2 SUB-02 17.12 484.00 71.63 520 2.32 39.76 31.33 0 00-35-02

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
540.00
0.00 0.00
2 Out-02 Outfall
556.00
0.00 0.00

Pre -Development 010 - Year
Subbasin Hydrology
Page 4
Subbasin : SUB-01
Input Data
Area(ac)------------------------------------------------------------------------
63-74
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
75-96
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Woods, Fair
14-32
D
79-00
Woods, Fair
10-68
D
79-00
Pasture, grassland, or range, Good
38-74
C
74-00
Composite Area & Weighted CN
63-74
75-96
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness

Pre -Development 010 - Year Page 5
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-23
Subbasin Runoff Results
Flowpath
Flowpath Flowpath
A
B
C
0-4
0-00
0-00
100
0-00
0-00
1
0-00
0-00
3-50
0-00
0-00
0-06
0-00
0-00
27-09
0-00
0-00
Flowpath
Flowpath
Flowpath
A
B
C
1771
0-00
0-00
4
0-00
0-00
Unpaved
Unpaved
Unpaved
323
0-00
0-00
9-14
0-00
0-00
Total Rainfall (in)------------------------------------------------------------ 520
Total Runoff (in)------------------------------------------------------------- 2-70
Peak Runoff (cfs)----------------------------------------------------------- 134-44
Weighted Curve Number----------------------------------------------- 75-96
Time of Concentration (days hh:mm:ss)------------------------ 0 0036:14

Pre -Development 010 - Year Page 6
Subbasin : SUB-01
7.6
7
6.6
6
5.6
5
4.6
4
3.5
3
2.6
2
1.6
05
140
136
130
126
120
115
110
106
100
95
90
85
80
75
v 70
0
65
60
55
50
45
40
35
30
25
20
15
10
5
Rainfall Intensity Graph
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
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
Subbasin : SUB-02
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 17-12
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 71-63
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
14-00
C
74-00
Pasture, grassland, or range, Good
3-12
B
61-00
Composite Area & Weighted CN
17-12
71-63
Time of Concentration
Flowpath
Flowpath Flowpath
Sheet Flow Computations
A
B C
Manning's Roughness :
-4
0-00 0-00
Flow Length (ft) :
100
0-00 0-00
Slope (%) :
1-11
0-00 0-00
2 yr, 24 hr Rainfall (in) :
3-50
0-00 0-00
Velocity (ft/sec) :
0-06
0-00 0-00
Computed Flow Time (min) :
25-99
0-00 0-00
Flowpath
Flowpath Flowpath
Shallow Concentrated Flow Computations
A
B C
Flow Length (ft) :
1531-55
0-00 0-00
Slope (%) :
3-06
0-00 0-00
Surface Type:
Unpaved
Unpaved Unpaved
Velocity (ft/sec) :
2-82
0-00 0-00
Computed Flow Time (min) :
9-05
0-00 0-00
Total TOC (min)------------------35-04
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 520
Total Runoff (in)------------------------------------------------------------- 2-32
Peak Runoff (cfs)----------------------------------------------------------- 31-33
Weighted Curve Number----------------------------------------------- 71-63
Time of Concentration (days hh:mm:ss)------------------------ 0 00-35-02

Pre -Development 010 - Year Page 8
Subbasin : SUB-02
8
7.6
7
6.6
6
55
5
4.6
v 4
3.6
3
2.6
2
1.6
0.5
34
32
30
28
26
24
22
20
v 18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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 1
Project Description
File Name .................................................... 27842.0002 - Pre Development.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 --------------------------------------
15
seconds
Number of Elements
Qty
Rain Gages
1
Subbasins
2
Nodes
2
Junctions
0
Outfalls
2
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
ID Factor Curve
Number
Total Total Total Peak Time of
Rainfall Runoff Runoff Runoff Concentration
Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 SUB-01 63.74 484.00 75.96 6.10 3.46 220.73 173.39 0 00-36-13
2 SUB-02 17.12 484.00 71.63 6.10 3.04 5206.41.46 0 00-35-02

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
540.00
0.00 0.00
2 Out-02 Outfall
556.00
0.00 0.00

Pre -Development 025 - Year
Subbasin Hydrology
Page 4
Subbasin : SUB-01
Input Data
Area(ac)------------------------------------------------------------------------
63-74
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
75-96
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Woods, Fair
14-32
D
79-00
Woods, Fair
10-68
D
79-00
Pasture, grassland, or range, Good
38-74
C
74-00
Composite Area & Weighted CN
63-74
75-96
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness

Pre -Development 025 - Year Page 5
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-23
Subbasin Runoff Results
Flowpath
Flowpath Flowpath
A
B
C
0-4
0-00
0-00
100
0-00
0-00
1
0-00
0-00
3-50
0-00
0-00
0-06
0-00
0-00
27-09
0-00
0-00
Flowpath
Flowpath
Flowpath
A
B
C
1771
0-00
0-00
4
0-00
0-00
Unpaved
Unpaved
Unpaved
323
0-00
0-00
9-14
0-00
0-00
Total Rainfall (in)------------------------------------------------------------ 6-10
Total Runoff (in)------------------------------------------------------------- 3-46
Peak Runoff (cfs)----------------------------------------------------------- 173-39
Weighted Curve Number----------------------------------------------- 75-96
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-14

Pre -Development 025 - Year Page 6
Subbasin : SUB-01
s.5
s
7.6
7
65
6
5.6
5
v 4.6
4
3.5
3
2.6
2
1.6
0.6
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : SUB-02
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 17-12
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 71-63
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
14-00
C
74-00
Pasture, grassland, or range, Good
3-12
B
61-00
Composite Area & Weighted CN
17-12
71-63
Time of Concentration
Flowpath
Flowpath Flowpath
Sheet Flow Computations
A
B C
Manning's Roughness :
-4
0-00 0-00
Flow Length (ft) :
100
0-00 0-00
Slope (%) :
1-11
0-00 0-00
2 yr, 24 hr Rainfall (in) :
3-50
0-00 0-00
Velocity (ft/sec) :
0-06
0-00 0-00
Computed Flow Time (min) :
25-99
0-00 0-00
Flowpath
Flowpath Flowpath
Shallow Concentrated Flow Computations
A
B C
Flow Length (ft) :
1531-55
0-00 0-00
Slope (%) :
3-06
0-00 0-00
Surface Type:
Unpaved
Unpaved Unpaved
Velocity (ft/sec) :
2-82
0-00 0-00
Computed Flow Time (min) :
9-05
0-00 0-00
Total TOC (min)------------------35-04
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6-10
Total Runoff (in)------------------------------------------------------------- 3-04
Peak Runoff (cfs)----------------------------------------------------------- 41-46
Weighted Curve Number----------------------------------------------- 71-63
Time of Concentration (days hh:mm:ss)------------------------ 0 00-35-02

Pre -Development 025 - Year Page 8
Subbasin : SUB-02
9
8.5
8
7.6
7
6.6
6
5.6
� 5
4.6
4
Or
3.6
3
2.6
2
1.6
0.5
44
42
40
38
36
34
32
30
28
26
� 24
v 22
0
20
18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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 1
Project Description
File Name .................................................... 27842.0002 - Pre Development.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 --------------------------------------
15
seconds
Number of Elements
Qty
Rain Gages
1
Subbasins
2
Nodes
2
Junctions
0
Outfalls
2
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
ID Factor Curve
Number
Total Total Total Peak Time of
Rainfall Runoff Runoff Runoff Concentration
Volume
(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)
1 SUB-01 63.74 484.00 75.96 6.90 4.16 265.41 208.73 0 00-36-13
2 SUB-02 17.12 484.00 71.63 6.90 3.71 63.44 50.84 0 00-35-02

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
540.00
0.00 0.00
2 Out-02 Outfall
556.00
0.00 0.00

Pre -Development 050 - Year
Subbasin Hydrology
Page 4
Subbasin : SUB-01
Input Data
Area(ac)------------------------------------------------------------------------
63-74
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
75-96
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Woods, Fair
14-32
D
79-00
Woods, Fair
10-68
D
79-00
Pasture, grassland, or range, Good
38-74
C
74-00
Composite Area & Weighted CN
63-74
75-96
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness

Pre -Development 050 - Year Page 5
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-23
Subbasin Runoff Results
Flowpath
Flowpath Flowpath
A
B
C
0-4
0-00
0-00
100
0-00
0-00
1
0-00
0-00
3-50
0-00
0-00
0-06
0-00
0-00
27-09
0-00
0-00
Flowpath
Flowpath
Flowpath
A
B
C
1771
0-00
0-00
4
0-00
0-00
Unpaved
Unpaved
Unpaved
323
0-00
0-00
9-14
0-00
0-00
Total Rainfall (in)------------------------------------------------------------ 6-90
Total Runoff (in)------------------------------------------------------------- 4-16
Peak Runoff (cfs)----------------------------------------------------------- 208-73
Weighted Curve Number----------------------------------------------- 75-96
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-14

Pre -Development 050 - Year Page 6
Subbasin : SUB-01
9.6
9
8.6
8
7.6
7
6.6
6
5.5
v 5
4.5
4
3.6
3
2.6
2
1.6
0.6
220
210
200
190
180
170
160
150
140
130
� 120
0
110
100
90
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : SUB-02
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 17-12
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 71-63
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
14-00
C
74-00
Pasture, grassland, or range, Good
3-12
B
61-00
Composite Area & Weighted CN
17-12
71-63
Time of Concentration
Flowpath
Flowpath Flowpath
Sheet Flow Computations
A
B C
Manning's Roughness :
-4
0-00 0-00
Flow Length (ft) :
100
0-00 0-00
Slope (%) :
1-11
0-00 0-00
2 yr, 24 hr Rainfall (in) :
3-50
0-00 0-00
Velocity (ft/sec) :
0-06
0-00 0-00
Computed Flow Time (min) :
25-99
0-00 0-00
Flowpath
Flowpath Flowpath
Shallow Concentrated Flow Computations
A
B C
Flow Length (ft) :
1531-55
0-00 0-00
Slope (%) :
3-06
0-00 0-00
Surface Type:
Unpaved
Unpaved Unpaved
Velocity (ft/sec) :
2-82
0-00 0-00
Computed Flow Time (min) :
9-05
0-00 0-00
Total TOC (min)------------------35-04
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6-90
Total Runoff (in)------------------------------------------------------------- 3-71
Peak Runoff (cfs)----------------------------------------------------------- 50-84
Weighted Curve Number----------------------------------------------- 71-63
Time of Concentration (days hh:mm:ss)------------------------ 0 00-35-02

Pre -Development 050 - Year Page 8
Subbasin : SUB-02
10
9.6
9
8.6
8
7.5
7
6.6
6
� 5.5
5
4.6
4
3.5
3
2.5
2
1.6
0.5
54
52
50
48
46
44
42
40
38
36
34
_ 32
30
28
0 26
24
22
20
18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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]

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 02
APPENDIX D
POST -DEVELOPMENT
DRAINAGE MAP
A THOMAS Sc HUTTON

WET DETEN N
•-:I•-,-L L-I--
/ POND I .. \ - _,_,_I_ - - --- I-�-\ '•�
OUTFALL 02
I-
" WET DETENTIO
POND 2
SHALLOW
CONCENTRATED
-� FLOW: 1102'
\ SHEET FLOW: -�\\r
1o0' �v I I -_ - vLOW PATH
HATCH LEGEND
PHASE 2 BUA TO POND 03
EXISTINGPHASEI
(' • ' /
PHASE 3 BUA TO POND 03 / � -:.•:� , �---: - - `----��'--� /' _
PHASE 3 BUTO POND 04 / /i :-;: t �— - \
AA I — — I• / _ _ SHEET FLOW r
P H A S E 4 BUA TO POND 04 / :'/ t �' , —-- L BMP ACCESS EASEMENT TO
L — J _E(TEND OUT TO EXISTING \
UNDISTURBED BASIN
POTTER ROAD RIGHT OF WAY
ysue-o1
AREA: 13.14 AC. �
...
I WILL OUGHBY ROA
Tc: 32 MIN / .:�:::>�� _. � _ _ _ �: \ _�...... . - '• "' \ \
.. �-• /// /' � , I .....;M�� \ \ � •_� .... , 60 PPUBLIC R/W
I. -- .r / --�
,• I ::Alsx�
EL y- \— I I'I II II Il >�:: - ,EVRONFLOW PATH _ _ -_ -_ -_ — II pl//\ NiNrnoN
;.: j � / - - - - - - L - = J` + fHL- L J L J/'/ /// i/ �' ^ \♦ / FUTURE / \ // )
IL , / �.� j._ ' WITH PK NAIL
/ / / :..• I. _ 7 _ r — .. ...................... ` ' < _ .:_:: /,' ELEV.
/ / ••• / / 'x I� .... �` // i < < \ AMENITY I t / = PROJECT BEN MARK
CENTER
I /, � \
\ /,/ Ilk��---
I-
\ SHALLOW _/_iy I-i 1 - - - - AREA: 45.3 AC. '/ > \ \< /,'� ,��� �•� / \; \
y _
CONCENTRATED � CN: 86
I OUTFACE 01
// i FLOW: 1370;i_ - - / LMIN. /j / �I / I =_ � << << \' i � \_ � ♦ � � \ / / �___ '§
/ E J'S/Til N G
L—_-111 Iq I'I pl �l ^ \� < yy � \y \• >n / /..... / --
I - -- J \ \ / ��� /
�PHASE I
— — ��</% �� \ � // / �r—�r
/ 4 / -;.. _ -� �•r DIET
EION �IUNDISTURBED BASIN PONDro3vry
SUB-02
AREA: 23.79 AC. /�/ \ �\ \ \ / / \ ��
I
- -
\CN: 79 \
Tc: 37 MIN. l \�` , \ \ 1. \ / �� /9
< v /
UNDISTURBED BASIN / \:
SUB-05
AREA: 43.5 AC. c. _
CN: 73 FUTURE
•/ / � � � �Av�A`-"' �"y� � VAS � < � . 1 \ _ �' V �v�� � Tc: 32 MIN. PHASE
P/
/
000
\ i\
PHASE 3 BASIN TO POND 04--
�
--
CN: 86--
� Tc: 5 MIN. �� \\ \\\ \ • � -- - � I. - - - :: � � � � --
\ I
/ WET DETENTION �� \ - J
FUTURE FUTURE - _
PHASE - =1 r PHASE f � ,
,_I �
FUTURE STORMWATER \
MANAGEMENT \ FUTURE ST MWA R I
BMP \ MANAGEM T
\ \-I \ — I - - POND 4 BMP I
—1 \ POND 5
/
OUTFALL 03
...........
`' --- -- GRAPHIC SCALE
...............................
200 0 100 200 1�41�)O
�
( IN FEET )
� I inch = 200 ft.
,
800
w
F-
a
0
r
m
0
z
0
Fn
w
cr
0
z
O
Lr)
E
Q
0
D�
0
0
O
> .
Q
c
2
-90
w cc)
E
0 z
CV
O �
O
>3
U
Q
�
U
J
w
�
CV
Q
w
Z
Wa.
Q
Q
z
Q -
=
�
0
_?
F—
L)
I
U
U
o
w
�z
z
z
a—
0
J0
U)
U)
U)
w
W
3
Ld
U
w
i
Y
U)
CL
JOB NO:
J-27842.0002
DATE:
01/06/21
DRAWN:
KSC
DESIGNED:
DAC
REVIEWED:
MSK
APPROVED:
MSK
SCALE:
I" = 200'
C3o22..i

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 02
APPENDIX E
POST -DEVELOPMENT CONDITIONS
DRAINAGE CALCULATIONS
27842.0002
Fq THOMAS Sc HUTTON

27842.0002
CRESSWIND WESLEY CHAPEL - PHASE 02
POST -DEVELOPMENT BASINS MODEL

Post -Development 002 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Post Development.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, 2020
00:00:00
End Analysis On .
Dec 04, 2020
00:00:00
Start Reporting On .
Dec 03, 2020
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
3
Nodes
5
Junctions
2
Outfalls
2
Flow Diversions
0
Inlets
0
Storage Nodes
1
Links
6
Channels
1
Pipes
1
Pumps
0
Orifices
2
Weirs
2
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 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-03
45.30
484.00
84.92
3.50
2.01
91.05
94.74
0 00-05-00
2 UNDISTURBED-BASIN-SUB-01
13.14
484.00
70.54
3.50
1.04
13.64
8.32
0 00-31-48
3 UNDISTURBED-BASIN-SUB-02
23.79
484.00
79.00
3.50
1.57
3726
22.56
0 00-36-57

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)
(ft') (cfs)
(ft)
(ft)
(ft) (days hh:mm)
(ac-in)
(min)
1 CS
Junction
555.00
57020
558.00
999.00
0.00 41.16
558.00
0.00
1220
0 00:00
0.00
0.00
2 Jun-03
Junction
559.00
57020
559.00
999.00
0.00 18.98
559.73
0.00
10.47
0 00:00
0.00
0.00
3 Out-01
Outfall
553.30
59.58
553.30
4 Out-02
Outfall
560.00
8.32
560.00
5 Pond-03 Storage Node
559.00
571.50
565.00
0.00 93.11
567.90
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)
( % )
(in)
(cfs)
(cfs)
(ft/sec)
(ft)
(min)
1 Outlet-Pipe-03 Pipe
Jun-03 CS
65.00
559.00
555.00
6.1500
42.000
0.0130 18.98
249.58
0.08 8.87
1.14
0.43 0.00 Calculated
2 Link-02 Channel
CS Out-01
50.00
555.00
554.90
02000
24.000
0.0010 59.58
712.92
0.08 15.05
0.93
0.59 0.00
3 CS-Rim-03 Orifice
Pond-03 Jun-03
559.00
559.00
60.000
0.00
4 WQ-Orifice-03 Orifice
Pond-03 Jun-03
559.00
559.00
4.000
0.71
5 Spillway-03 Weir
Pond-03 CS
559.00
555.00
0.00
6 Weir-03A Weir
Pond-03 Jun-03
559.00
559.00
1827

Post -Development 002 - Year
Subbasin Hydrology
Page 5
Subbasin : SUB-03
Input Data
Area(ac)------------------------------------------------------------------------
45-30
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
84-92
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Paved parking & roofs
13-69
B
98-00
> 75 % grass cover, Good
16-02
B
61-00
Future -Paved parking & roofs
15-59
B
98-00
Composite Area & Weighted CN
45-30
84-92
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness
User -Defined TOC override (minutes): 5-00
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 3-50
Total Runoff (in)------------------------------------------------------------- 2-01
Peak Runoff (cfs)----------------------------------------------------------- 94-74
Weighted Curve Number----------------------------------------------- 84-92
Time of Concentration (days hh:mm:ss)------------------------ 0 00-05-00

Post -Development 002 - Year Page 6
Subbasin : SUB-03
3
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
02
0.1
100
95
90
85
80
75
70
65
60
55
u 50
0
45
40
35
30
25
20
15
10
5
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASINSUB-01
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 13.14
Peak Rate Factor----------------------------------------------------------- 484.00
Weighted Curve Number ----------------------------------------------- 70.54
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
3.13
B
61.00
9.65
74.00
0.37
61.00
Composite Area & Weighted CN
13.15
70.54
Time of Concentration
Subarea
Subarea
Subarea
Sheet Flow Computations
A
B
C
Manning's Roughness :
.4
0.00
0.00
Flow Length (ft) :
100
0.00
0.00
Slope (%) :
.67
0.00
0.00
2 yr, 24 hr Rainfall (in) :
3.50
0.00
0.00
Velocity (ft/sec) :
0.05
0.00
0.00
Computed Flow Time (min) :
31.80
0.00
0.00
Total TOC (min) ..................31.80
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 3.50
Total Runoff (in)------------------------------------------------------------- 1.04
Peak Runoff (cfs)........................................................... 8.32
Weighted Curve Number ............................................... 70.54
Time of Concentration (days hh:mm:ss) ------------------------ 0 0031:48

Post -Development 002 - Year Page 8
Subbasin : UNDISTURBED-BASIN-SUB-01
3.1
3
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2
1.9
1.8
1.7
u 1.6
1.5
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
9
8.5
8
7.5
7
6.5
6
5.5
5
4.5
❑
4
3.5
3
2.5
2
1.5
1
0.5
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASIN-SUB-02
Page 9
Input Data
Area(ac)------------------------------------------------------------------------ 23-79
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 79-00
Rain Gage ID - Rain Gage-001
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
Woods, Fair 23-79 D 79-00
Composite Area & Weighted CN 23-79 79-00
Time of Concentration
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-96
Subbasin Runoff Results
Subarea Subarea Subarea
A B C
-4 0-00 0-00
100 0-00 0-00
9-5 0-00 0-00
3-50 0-00 0-00
0-15 0-00 0-00
11-01 0-00 0-00
Subarea Subarea Subarea
A B C
1370 0-00 0-00
-3 0-00 0-00
Unpaved Unpaved Unpaved
0-88 0-00 0-00
25-95 0-00 0-00
Total Rainfall (in)------------------------------------------------------------ 3-50
Total Runoff (in)------------------------------------------------------------- 1-57
Peak Runoff (cfs)----------------------------------------------------------- 22-56
Weighted Curve Number----------------------------------------------- 79-00
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-58

Post -Development 002 - Year Page 10
Subbasin : UNDISTURBED-BASIN-SUB-02
3.1
3
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2
1.9
1.8
1.7
u 1.6
1.5
1.4
M
ry 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
24
23
22
21
20
19
18
17
16
15
14
13
u 12
0
� 11
1h 10
9
8
7
6
5
4
3
2
1
Rainfall Intensity Graph
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
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 11
Channel Input
SN Element Length Inlet Inlet
Outlet Outlet Total Average Shape
Height Width Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert
Invert Invert Drop
Slope
Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset
(ft) (ft) (ft)
(ft) (ft) (ft)
( % )
(ft) (ft) (cfs)
1 Link-02 50.00 555.00 0.00
554.90 1.60 0.10
02000 Rectangular
2000.5.000 0.0010 0.5000 0.5000 0.0000 0.00 No

Post -Development 002 - Year Page 12
Channel 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 Link-02 59.58 0 00:00 712.92 0.08 15.05 0.06 0.93 0.59 0.00

Post -Development 002 - Year Page 13
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) ( % ) (in) (in) (cfs)
1 Outlet-Pipe-03 65.00 559.00 0.00 555.00 0.00 4.00 6.1500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No

Post -Development 002 - Year Page 14
No. of
Barrels

Post -Development 002 - Year Page 15
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-03 18.98 0 12:37 249.58 0.08 8.87 0.12 1.14 0.43 0.00 Calculated

Post -Development 002 - Year Page 16
Storage Nodes
Storage Node : Pond-03
Input Data
Invert Elevation (ft)--------------------------------------------------------------------
559-00
Max (Rim) Elevation (ft)------------------------------------------------------------
571-50
Max (Rim) Offset (ft)-----------------------------------------------------------------
12-50
Initial Water Elevation (ft)----------------------------------------------------------
565-00
Initial Water Depth (ft)---------------------------------------------------------------
6-00
Ponded Area (ft) -----------------------------------------------------------------------
0-00
Evaporation Loss-----------------------------------------------------------------------
0-00
Outflow Weirs
SIN Element
Weir Flap
Crest
Crest
Length
Weir Total Discharge
ID
Type Gate
Elevation
Offset
Height Coefficient
(ft)
(ft)
(ft)
(ft)
1 Spillway-03
Trapezoidal No
571-00
12-00
50-00
0-50 3-33
2 Weir-03A
Rectangular No
566-80
7-80
5-00
120 3-33
Outflow Orifices
SIN 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-03 Bottom
Rectangular No
60-00
60-00
568-00 0-63
2 WQ-Orifice-03 Side
CIRCULAR
No
4-00
565-00 0-61
Output Summary Results
Peak Inflow (cfs)------------------------------------------------------------------------
93-11
Peak Lateral Inflow (cfs)------------------------------------------------------------
93-11
Peak Outflow (cfs)---------------------------------------------------------------------
18-98
Peak Exfiltration Flow Rate (cfm)----------------------------------------------
0-00
Max HGL Elevation Attained (ft)------------------------------------------------
567-90
Max HGL Depth Attained (ft)-----------------------------------------------------
89
Average HGL Elevation Attained (ft)-----------------------------------------
566-13
Average HGL Depth Attained (ft)----------------------------------------------
7-13
Time of Max HGL Occurrence (days hh:mm)---------------------------
0 12-37
Total Exfiltration Volume (1000-ft3)-------------------------------------------
0-000
Total Flooded Volume (ac-in) -
0
Total Time Flooded (min)
0
Total Retention Time (sec) --------------------------------------------------------
0-00

Post -Development 010 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Post Development.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, 2020
00:00:00
End Analysis On .
Dec 04, 2020
00:00:00
Start Reporting On .
Dec 03, 2020
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
3
Nodes
5
Junctions
2
Outfalls
2
Flow Diversions
0
Inlets
0
Storage Nodes
1
Links
6
Channels
1
Pipes
1
Pumps
0
Orifices
2
Weirs
2
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 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-03
45.30
484.00
84.92
520
3.55
160.59 163.12
0 00-05-00
2 UNDISTURBED-BASIN-SUB-01
13.14
484.00
70.54
520
223
29.30 18.96
0 00-31-48
3 UNDISTURBED-BASIN-SUB-02
23.79
484.00
79.00
520
2.98
70.78 43.39
0 00-36-57

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)
(ft')
(cfs)
(ft)
(ft)
(ft) (days hh:mm)
(ac-in)
(min)
1 CS
Junction
555.00
57020
558.00
999.00
0.00
123.97
560.66
0.00
9.54
0 00:00
0.00
0.00
2 Jun-03
Junction
559.00
57020
559.00
999.00
0.00
88.13
56229
0.00
7.91
0 00:00
0.00
0.00
3 Out-01
Outfall
553.30
123.96
553.30
4 Out-02
Outfall
560.00
18.85
560.00
5 Pond-03 Storage Node
559.00
571.50
565.00
0.00
16125
568.88
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)
( % )
(in)
(cfs)
(cfs)
(ft/sec)
(ft)
(min)
1 Outlet-Pipe-03 Pipe
Jun-03 CS
65.00
559.00
555.00
6.1500
42.000
0.0130 88.01
249.58
0.35 9.52
3.38
0.97 0.00 Calculated
2 Link-02 Channel
CS Out-01
50.00
555.00
554.90
02000
24.000
0.0010 123.96
712.92
0.17 1905.
1.30
0.65 0.00
3 CS-Rim-03 Orifice
Pond-03 Jun-03
559.00
559.00
60.000
54.61
4 WQ-Orifice-03 Orifice
Pond-03 Jun-03
559.00
559.00
4.000
0.83
5 Spillway-03 Weir
Pond-03 CS
559.00
555.00
0.00
6 Weir-03A Weir
Pond-03 Jun-03
559.00
559.00
32.70

Post -Development 010 - Year
Subbasin Hydrology
Page 5
Subbasin : SUB-03
Input Data
Area(ac)------------------------------------------------------------------------
45-30
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
84-92
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Paved parking & roofs
13-69
B
98-00
> 75 % grass cover, Good
16-02
B
61-00
Future -Paved parking & roofs
15-59
B
98-00
Composite Area & Weighted CN
45-30
84-92
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness
User -Defined TOC override (minutes): 5-00
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 520
Total Runoff (in)------------------------------------------------------------- 3-55
Peak Runoff (cfs)----------------------------------------------------------- 163-12
Weighted Curve Number----------------------------------------------- 84-92
Time of Concentration (days hh:mm:ss)------------------------ 0 00-05-00

Post -Development 010 - Year Page 6
Subbasin : SUB-03
4.4
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
180
170
160
150
140
130
120
110
100
u 90
0
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASINSUB-01
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 13.14
Peak Rate Factor----------------------------------------------------------- 484.00
Weighted Curve Number ----------------------------------------------- 70.54
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
3.13
B
61.00
9.65
74.00
0.37
61.00
Composite Area & Weighted CN
13.15
70.54
Time of Concentration
Subarea
Subarea
Subarea
Sheet Flow Computations
A
B
C
Manning's Roughness :
.4
0.00
0.00
Flow Length (ft) :
100
0.00
0.00
Slope (%) :
.67
0.00
0.00
2 yr, 24 hr Rainfall (in) :
3.50
0.00
0.00
Velocity (ft/sec) :
0.05
0.00
0.00
Computed Flow Time (min) :
31.80
0.00
0.00
Total TOC (min) ..................31.80
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 5.20
Total Runoff (in)------------------------------------------------------------- 2.23
Peak Runoff (cfs)........................................................... 18.96
Weighted Curve Number ............................................... 70.54
Time of Concentration (days hh:mm:ss) ------------------------ 0 0031:48

Post -Development 010 - Year Page 8
Subbasin : UNDISTURBED-BASIN-SUB-01
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
3
2.8
2.6
2.4
2.2
M 2
FY
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
Rainfall Intensity Graph
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
20
19
18--
17--
16--
10-
0
� g
1h
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 010 - Year
Subbasin : UNDISTURBED-BASIN-SUB-02
Page 9
Input Data
Area(ac)------------------------------------------------------------------------ 23-79
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 79-00
Rain Gage ID - Rain Gage-001
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
Woods, Fair 23-79 D 79-00
Composite Area & Weighted CN 23-79 79-00
Time of Concentration
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-96
Subbasin Runoff Results
Subarea Subarea Subarea
A B C
-4 0-00 0-00
100 0-00 0-00
9-5 0-00 0-00
3-50 0-00 0-00
0-15 0-00 0-00
11-01 0-00 0-00
Subarea Subarea Subarea
A B C
1370 0-00 0-00
-3 0-00 0-00
Unpaved Unpaved Unpaved
0-88 0-00 0-00
25-95 0-00 0-00
Total Rainfall (in)------------------------------------------------------------ 520
Total Runoff (in)------------------------------------------------------------- 2-98
Peak Runoff (cfs)----------------------------------------------------------- 43-39
Weighted Curve Number----------------------------------------------- 79-00
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-58

Post -Development 010 - Year Page 10
Subbasin : UNDISTURBED-BASIN-SUB-02
4.6
4.4
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
46
44
42
40
38
36
34
32
30
28
n 26
-- 24
0 22
20
18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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 11
Channel Input
SN Element Length Inlet Inlet
Outlet Outlet Total Average Shape
Height Width Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert
Invert Invert Drop
Slope
Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset
(ft) (ft) (ft)
(ft) (ft) (ft)
( % )
(ft) (ft) (cfs)
1 Link-02 50.00 555.00 0.00
554.90 1.60 0.10
02000 Rectangular
2000.5.000 0.0010 0.5000 0.5000 0.0000 0.00 No

Post -Development 010 - Year Page 12
Channel 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 Link-02 123.96 0 1223 712.92 0.17 1905.0.04 1.30 0.65 0.00

Post -Development 010 - Year Page 13
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) ( % ) (in) (in) (cfs)
1 Outlet-Pipe-03 65.00 559.00 0.00 555.00 0.00 4.00 6.1500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No

Post -Development 010 - Year Page 14
No. of
Barrels

Post -Development 010 - Year Page 15
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-03 88.01 0 12:19 249.58 0.35 9.52 0.11 3.38 0.97 0.00 Calculated

Post -Development 010 - Year Page 16
Storage Nodes
Storage Node : Pond-03
Input Data
Invert Elevation (ft)--------------------------------------------------------------------
559-00
Max (Rim) Elevation (ft)------------------------------------------------------------
571-50
Max (Rim) Offset (ft)-----------------------------------------------------------------
12-50
Initial Water Elevation (ft)----------------------------------------------------------
565-00
Initial Water Depth (ft)---------------------------------------------------------------
6-00
Ponded Area (ft) -----------------------------------------------------------------------
0-00
Evaporation Loss-----------------------------------------------------------------------
0-00
Outflow Weirs
SIN Element
Weir Flap
Crest
Crest
Length
Weir Total Discharge
ID
Type Gate
Elevation
Offset
Height Coefficient
(ft)
(ft)
(ft)
(ft)
1 Spillway-03
Trapezoidal No
571-00
12-00
50-00
0-50 3-33
2 Weir-03A
Rectangular No
566-80
7-80
5-00
120 3-33
Outflow Orifices
SIN 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-03 Bottom
Rectangular No
60-00
60-00
568-00 0-63
2 WQ-Orifice-03 Side
CIRCULAR
No
4-00
565-00 0-61
Output Summary Results
Peak Inflow (cfs)------------------------------------------------------------------------
16125
Peak Lateral Inflow (cfs)------------------------------------------------------------
16125
Peak Outflow (cfs)---------------------------------------------------------------------
88-13
Peak Exfiltration Flow Rate (cfm)----------------------------------------------
0-00
Max HGL Elevation Attained (ft)------------------------------------------------
568-88
Max HGL Depth Attained (ft)-----------------------------------------------------
9-88
Average HGL Elevation Attained (ft)-----------------------------------------
566-30
Average HGL Depth Attained (ft)----------------------------------------------
7-3
Time of Max HGL Occurrence (days hh:mm)---------------------------
0 12-19
Total Exfiltration Volume (1000-ft3)-------------------------------------------
0-000
Total Flooded Volume (ac-in) -
0
Total Time Flooded (min)
0
Total Retention Time (sec) --------------------------------------------------------
0-00

Post -Development 025 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Post Development.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, 2020
00:00:00
End Analysis On .
Dec 04, 2020
00:00:00
Start Reporting On .
Dec 03, 2020
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
3
Nodes
5
Junctions
2
Outfalls
2
Flow Diversions
0
Inlets
0
Storage Nodes
1
Links
6
Channels
1
Pipes
1
Pumps
0
Orifices
2
Weirs
2
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 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-03
45.30
484.00
84.92
6.10
4.39
198.78 199.42
0 00-05-00
2 UNDISTURBED-BASIN-SUB-01
13.14
484.00
70.54
6.10
2.94
38.58 2520
0 00-31-48
3 UNDISTURBED-BASIN-SUB-02
23.79
484.00
79.00
6.10
3.77
89.66 54.85
0 00-36-57

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
555.00
57020
558.00
999.00
0.00 169.68
563.91
0.00
629
0 00:00
0.00
0.00
2 Jun-03
Junction
559.00
57020
559.00
999.00
0.00 129.72
567.58
0.00
2.62
0 00:00
0.00
0.00
3 Out-01
Outfall
553.30
169.61
553.30
4 Out-02
Outfall
560.00
24.96
560.00
5 Pond-03 Storage Node
559.00
571.50
565.00
0.00 197.59
56925
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)
( % )
(in)
(cfs)
(cfs)
(ft/sec)
(ft)
(min)
1 Outlet-Pipe-03 Pipe
Jun-03 CS
65.00
559.00
555.00
6.1500
42.000
0.0130 129.47
249.58
0.52 13.46
3.50
1.00 26.00 SURCHARGED
2 Link-02 Channel
CS Out-01
50.00
555.00
554.90
02000
24.000
0.0010 169.61
712.92
024 24.75
1.37
0.69 0.00
3 CS-Rim-03 Orifice
Pond-03 Jun-03
559.00
559.00
60.000
93.04
4 WQ-Orifice-03 Orifice
Pond-03 Jun-03
559.00
559.00
4.000
0.86
5 Spillway-03 Weir
Pond-03 CS
559.00
555.00
0.00
6 Weir-03A Weir
Pond-03 Jun-03
559.00
559.00
36.56

Post -Development 025 - Year
Subbasin Hydrology
Page 5
Subbasin : SUB-03
Input Data
Area(ac)------------------------------------------------------------------------
45-30
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
84-92
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Paved parking & roofs
13-69
B
98-00
> 75 % grass cover, Good
16-02
B
61-00
Future -Paved parking & roofs
15-59
B
98-00
Composite Area & Weighted CN
45-30
84-92
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness
User -Defined TOC override (minutes): 5-00
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6-10
Total Runoff (in)------------------------------------------------------------- 4-39
Peak Runoff (cfs)----------------------------------------------------------- 199-42
Weighted Curve Number----------------------------------------------- 84-92
Time of Concentration (days hh:mm:ss)------------------------ 0 00-05-00

Post -Development 025 - Year Page 6
Subbasin : SUB-03
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
3
2.8
2.6
2.4
ry 2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
210
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASINSUB-01
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 13.14
Peak Rate Factor----------------------------------------------------------- 484.00
Weighted Curve Number ----------------------------------------------- 70.54
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
3.13
B
61.00
9.65
74.00
0.37
61.00
Composite Area & Weighted CN
13.15
70.54
Time of Concentration
Subarea
Subarea
Subarea
Sheet Flow Computations
A
B
C
Manning's Roughness :
.4
0.00
0.00
Flow Length (ft) :
100
0.00
0.00
Slope (%) :
.67
0.00
0.00
2 yr, 24 hr Rainfall (in) :
3.50
0.00
0.00
Velocity (ft/sec) :
0.05
0.00
0.00
Computed Flow Time (min) :
31.80
0.00
0.00
Total TOC (min) ..................31.80
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6.10
Total Runoff (in)------------------------------------------------------------- 2.94
Peak Runoff (cfs)........................................................... 25.20
Weighted Curve Number ............................................... 70.54
Time of Concentration (days hh:mm:ss) ------------------------ 0 0031:48

Post -Development 025 - Year Page 8
Subbasin : UNDISTURBED-BASIN-SUB-01
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
3
28
2.6
2.4
2.2
2
1.8
1.6
14
1.2
1
0.8
0.6
0.4
0.2
26
25
24
23
22
21
20
19
18
17
16
15
14
u 13
0
12
� 11
10
9
8
7
6
5
4
3
2
1
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASIN-SUB-02
Page 9
Input Data
Area(ac)------------------------------------------------------------------------ 23-79
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 79-00
Rain Gage ID - Rain Gage-001
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
Woods, Fair 23-79 D 79-00
Composite Area & Weighted CN 23-79 79-00
Time of Concentration
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-96
Subbasin Runoff Results
Subarea Subarea Subarea
A B C
-4 0-00 0-00
100 0-00 0-00
9-5 0-00 0-00
3-50 0-00 0-00
0-15 0-00 0-00
11-01 0-00 0-00
Subarea Subarea Subarea
A B C
1370 0-00 0-00
-3 0-00 0-00
Unpaved Unpaved Unpaved
0-88 0-00 0-00
25-95 0-00 0-00
Total Rainfall (in)------------------------------------------------------------ 6-10
Total Runoff (in)------------------------------------------------------------- 3-77
Peak Runoff (cfs)----------------------------------------------------------- 54-85
Weighted Curve Number----------------------------------------------- 79-00
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-58

Post -Development 025 - Year Page 10
Subbasin : UNDISTURBED-BASIN-SUB-02
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
3
28
2.6
2.4
2.2
2
1.8
1.6
14
1.2
1
0.8
0.6
0.4
0.2
58
56
54
52
50
48
46
44
42
40
38
36
_ 34
32
30
0 28
26
24
22
20
18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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 11
Channel Input
SN Element Length Inlet Inlet
Outlet Outlet Total Average Shape
Height Width Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert
Invert Invert Drop
Slope
Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset
(ft) (ft) (ft)
(ft) (ft) (ft)
( % )
(ft) (ft) (cfs)
1 Link-02 50.00 555.00 0.00
554.90 1.60 0.10
02000 Rectangular
2000.5.000 0.0010 0.5000 0.5000 0.0000 0.00 No

Post -Development 025 - Year Page 12
Channel 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 Link-02 169.61 0 1220 712.92 024 24.75 0.03 1.37 0.69 0.00

Post -Development 025 - Year Page 13
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) ( % ) (in) (in) (cfs)
1 Outlet-Pipe-03 65.00 559.00 0.00 555.00 0.00 4.00 6.1500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No

Post -Development 025 - Year Page 14
No. of
Barrels

Post -Development 025 - Year Page 15
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-03 129.47 0 12:15 249.58 0.52 13.46 0.08 3.50 1.00 26.00 SURCHARGED

Post -Development 025 - Year Page 16
Storage Nodes
Storage Node : Pond-03
Input Data
Invert Elevation (ft)--------------------------------------------------------------------
559-00
Max (Rim) Elevation (ft)------------------------------------------------------------
571-50
Max (Rim) Offset (ft)-----------------------------------------------------------------
12-50
Initial Water Elevation (ft)----------------------------------------------------------
565-00
Initial Water Depth (ft)---------------------------------------------------------------
6-00
Ponded Area (ft) -----------------------------------------------------------------------
0-00
Evaporation Loss-----------------------------------------------------------------------
0-00
Outflow Weirs
SIN Element
Weir Flap
Crest
Crest
Length
Weir Total Discharge
ID
Type Gate
Elevation
Offset
Height Coefficient
(ft)
(ft)
(ft)
(ft)
1 Spillway-03
Trapezoidal No
571-00
12-00
50-00
0-50 3-33
2 Weir-03A
Rectangular No
566-80
7-80
5-00
120 3-33
Outflow Orifices
SIN 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-03 Bottom
Rectangular No
60-00
60-00
568-00 0-63
2 WQ-Orifice-03 Side
CIRCULAR
No
4-00
565-00 0-61
Output Summary Results
Peak Inflow (cfs)------------------------------------------------------------------------
197-59
Peak Lateral Inflow (cfs)------------------------------------------------------------
197-59
Peak Outflow (cfs)---------------------------------------------------------------------
129-72
Peak Exfiltration Flow Rate (cfm)----------------------------------------------
0-00
Max HGL Elevation Attained (ft)------------------------------------------------
56925
Max HGL Depth Attained (ft)-----------------------------------------------------
1025
Average HGL Elevation Attained (ft)-----------------------------------------
566-39
Average HGL Depth Attained (ft)----------------------------------------------
7-39
Time of Max HGL Occurrence (days hh:mm)---------------------------
0 12-16
Total Exfiltration Volume (1000-ft3)-------------------------------------------
0-000
Total Flooded Volume (ac-in) -
0
Total Time Flooded (min)
0
Total Retention Time (sec) --------------------------------------------------------
0-00

Post -Development 050 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Post Development.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, 2020
00:00:00
End Analysis On .
Dec 04, 2020
00:00:00
Start Reporting On .
Dec 03, 2020
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
3
Nodes
5
Junctions
2
Outfalls
2
Flow Diversions
0
Inlets
0
Storage Nodes
1
Links
6
Channels
1
Pipes
1
Pumps
0
Orifices
2
Weirs
2
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 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-03
45.30
484.00
84.92
6.90
5.15
23320 231.78
0 00-05-00
2 UNDISTURBED-BASIN-SUB-01
13.14
484.00
70.54
6.90
3.59
47.19 30.95
0 00-31-48
3 UNDISTURBED-BASIN-SUB-02
23.79
484.00
79.00
6.90
4.49
106.89 6523
0 00-36-57

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)
(ft') (cfs)
(ft)
(ft)
(ft) (days hh:mm)
(ac-in)
(min)
1 CS
Junction
555.00
57020
558.00
999.00
0.00 18323
564.98
0.00
522
0 00:00
0.00
0.00
2 Jun-03
Junction
559.00
57020
559.00
999.00
0.00 13723
568.37
0.00
1.83
0 00:00
0.00
0.00
3 Out-01
Outfall
553.30
18323
553.30
4 Out-02
Outfall
560.00
30.60
560.00
5 Pond-03 Storage Node
559.00
571.50
565.00
0.00 229.90
569.68
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)
( % )
(in)
(cfs)
(cfs)
(ft/sec)
(ft)
(min)
1 Outlet-Pipe-03 Pipe
Jun-03 CS
65.00
559.00
555.00
6.1500
42.000
0.0130 136.69
249.58
0.55 1421
3.50
1.00 37.00 SURCHARGED
2 Link-02 Channel
CS Out-01
50.00
555.00
554.90
02000
24.000
0.0010 18323
712.92
026 26.36
1.39
0.69 0.00
3 CS-Rim-03 Orifice
Pond-03 Jun-03
559.00
559.00
60.000
105.30
4 WQ-Orifice-03 Orifice
Pond-03 Jun-03
559.00
559.00
4.000
0.86
5 Spillway-03 Weir
Pond-03 CS
559.00
555.00
0.00
6 Weir-03A Weir
Pond-03 Jun-03
559.00
559.00
37.02

Post -Development 050 - Year
Subbasin Hydrology
Page 5
Subbasin : SUB-03
Input Data
Area(ac)------------------------------------------------------------------------
45-30
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
84-92
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Paved parking & roofs
13-69
B
98-00
> 75 % grass cover, Good
16-02
B
61-00
Future -Paved parking & roofs
15-59
B
98-00
Composite Area & Weighted CN
45-30
84-92
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness
User -Defined TOC override (minutes): 5-00
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6-90
Total Runoff (in)------------------------------------------------------------- 5-15
Peak Runoff (cfs)----------------------------------------------------------- 231-78
Weighted Curve Number----------------------------------------------- 84-92
Time of Concentration (days hh:mm:ss)------------------------ 0 00-05-00

Post -Development 050 - Year Page 6
Subbasin : SUB-03
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
3.2
u 3
2.8
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
04
0.2
240
230
220
210
200
190
180
170
160
150
140
130
120
S 110
1h 100
90
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASINSUB-01
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 13.14
Peak Rate Factor----------------------------------------------------------- 484.00
Weighted Curve Number ----------------------------------------------- 70.54
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
3.13
B
61.00
9.65
74.00
0.37
61.00
Composite Area & Weighted CN
13.15
70.54
Time of Concentration
Subarea
Subarea
Subarea
Sheet Flow Computations
A
B
C
Manning's Roughness :
.4
0.00
0.00
Flow Length (ft) :
100
0.00
0.00
Slope (%) :
.67
0.00
0.00
2 yr, 24 hr Rainfall (in) :
3.50
0.00
0.00
Velocity (ft/sec) :
0.05
0.00
0.00
Computed Flow Time (min) :
31.80
0.00
0.00
Total TOC (min) ..................31.80
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 6.90
Total Runoff (in)------------------------------------------------------------- 3.59
Peak Runoff (cfs)........................................................... 30.95
Weighted Curve Number ............................................... 70.54
Time of Concentration (days hh:mm:ss) ------------------------ 0 0031:48

Post -Development 050 - Year Page 8
Subbasin : UNDISTURBED-BASIN-SUB-01
6.2
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
u 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
34
32
30
28
26
24
22
20
u 18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASIN-SUB-02
Page 9
Input Data
Area(ac)------------------------------------------------------------------------ 23-79
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 79-00
Rain Gage ID - Rain Gage-001
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
Woods, Fair 23-79 D 79-00
Composite Area & Weighted CN 23-79 79-00
Time of Concentration
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-96
Subbasin Runoff Results
Subarea Subarea Subarea
A B C
-4 0-00 0-00
100 0-00 0-00
9-5 0-00 0-00
3-50 0-00 0-00
0-15 0-00 0-00
11-01 0-00 0-00
Subarea Subarea Subarea
A B C
1370 0-00 0-00
-3 0-00 0-00
Unpaved Unpaved Unpaved
0-88 0-00 0-00
25-95 0-00 0-00
Total Rainfall (in)------------------------------------------------------------ 6-90
Total Runoff (in)------------------------------------------------------------- 4-49
Peak Runoff (cfs)----------------------------------------------------------- 6523
Weighted Curve Number----------------------------------------------- 79-00
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-58

Post -Development 050 - Year Page 10
Subbasin : UNDISTURBED-BASIN-SUB-02
6.2
6
5.8
5.6
5.4
5.2
5
4.8
4.6
4.4
4.2
4
3.8
3.6
3.4
u 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
75
70
65
60
55
50
45
40
0
� 35
30
25
20
15
10
5
Rainfall Intensity Graph
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
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 11
Channel Input
SN Element Length Inlet Inlet
Outlet Outlet Total Average Shape
Height Width Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert
Invert Invert Drop
Slope
Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset
(ft) (ft) (ft)
(ft) (ft) (ft)
( % )
(ft) (ft) (cfs)
1 Link-02 50.00 555.00 0.00
554.90 1.60 0.10
02000 Rectangular
2000.5.000 0.0010 0.5000 0.5000 0.0000 0.00 No

Post -Development 050 - Year Page 12
Channel 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 Link-02 18323 0 1229 712.92 026 26.36 0.03 1.39 0.69 0.00

Post -Development 050 - Year Page 13
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) ( % ) (in) (in) (cfs)
1 Outlet-Pipe-03 65.00 559.00 0.00 555.00 0.00 4.00 6.1500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No

Post -Development 050 - Year Page 14
No. of
Barrels

Post -Development 050 - Year Page 15
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-03 136.69 0 12:10 249.58 0.55 1421 0.08 3.50 1.00 37.00 SURCHARGED

Post -Development 050 - Year Page 16
Storage Nodes
Storage Node : Pond-03
Input Data
Invert Elevation (ft)--------------------------------------------------------------------
559-00
Max (Rim) Elevation (ft)------------------------------------------------------------
571-50
Max (Rim) Offset (ft)-----------------------------------------------------------------
12-50
Initial Water Elevation (ft)----------------------------------------------------------
565-00
Initial Water Depth (ft)---------------------------------------------------------------
6-00
Ponded Area (ft) -----------------------------------------------------------------------
0-00
Evaporation Loss-----------------------------------------------------------------------
0-00
Outflow Weirs
SIN Element
Weir Flap
Crest
Crest
Length
Weir Total Discharge
ID
Type Gate
Elevation
Offset
Height Coefficient
(ft)
(ft)
(ft)
(ft)
1 Spillway-03
Trapezoidal No
571-00
12-00
50-00
0-50 3-33
2 Weir-03A
Rectangular No
566-80
7-80
5-00
120 3-33
Outflow Orifices
SIN 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-03 Bottom
Rectangular No
60-00
60-00
568-00 0-63
2 WQ-Orifice-03 Side
CIRCULAR
No
4-00
565-00 0-61
Output Summary Results
Peak Inflow (cfs)------------------------------------------------------------------------
229-90
Peak Lateral Inflow (cfs)------------------------------------------------------------
229-90
Peak Outflow (cfs)---------------------------------------------------------------------
13723
Peak Exfiltration Flow Rate (cfm)----------------------------------------------
0-00
Max HGL Elevation Attained (ft)------------------------------------------------
569-68
Max HGL Depth Attained (ft)-----------------------------------------------------
10-68
Average HGL Elevation Attained (ft)-----------------------------------------
566-47
Average HGL Depth Attained (ft)----------------------------------------------
7-47
Time of Max HGL Occurrence (days hh:mm)---------------------------
0 12-18
Total Exfiltration Volume (1000-ft3)-------------------------------------------
0-000
Total Flooded Volume (ac-in) -
0
Total Time Flooded (min)
0
Total Retention Time (sec) --------------------------------------------------------
0-00

Post -Development 100 - Year Page 1
Project Description
File Name .................................................... 27842.0002 - Post Development.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, 2020
00:00:00
End Analysis On .
Dec 04, 2020
00:00:00
Start Reporting On .
Dec 03, 2020
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
3
Nodes
5
Junctions
2
Outfalls
2
Flow Diversions
0
Inlets
0
Storage Nodes
1
Links
6
Channels
1
Pipes
1
Pumps
0
Orifices
2
Weirs
2
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 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-03
45.30
484.00
84.92
7.50
5.72
25925 255.91
0 00-05-00
2 UNDISTURBED-BASIN-SUB-01
13.14
484.00
70.54
7.50
4.10
53.83 35.31
0 00-31-48
3 UNDISTURBED-BASIN-SUB-02
23.79
484.00
79.00
7.50
5.04
120.00 73.04
0 00-36-57

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)
(ft') (cfs)
(ft)
(ft)
(ft) (days hh:mm)
(ac-in)
(min)
1 CS
Junction
555.00
57020
558.00
999.00
0.00 189.64
565.50
0.00
4.70
0 00:00
0.00
0.00
2 Jun-03
Junction
559.00
57020
559.00
999.00
0.00 137.62
568.74
0.00
1.46
0 00:00
0.00
0.00
3 Out-01
Outfall
553.30
189.61
553.30
4 Out-02
Outfall
560.00
34.89
560.00
5 Pond-03 Storage Node
559.00
571.50
565.00
0.00 254.07
570.05
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)
( % )
(in)
(cfs)
(cfs)
(ft/sec)
(ft)
(min)
1 Outlet-Pipe-03 Pipe
Jun-03 CS
65.00
559.00
555.00
6.1500
42.000
0.0130 137.01
249.58
0.55 1424
3.50
1.00 45.00 SURCHARGED
2 Link-02 Channel
CS Out-01
50.00
555.00
554.90
02000
24.000
0.0010 189.61
712.92
027 27.11
1.40
0.70 0.00
3 CS-Rim-03 Orifice
Pond-03 Jun-03
559.00
559.00
60.000
105.58
4 WQ-Orifice-03 Orifice
Pond-03 Jun-03
559.00
559.00
4.000
0.86
5 Spillway-03 Weir
Pond-03 CS
559.00
555.00
0.00
6 Weir-03A Weir
Pond-03 Jun-03
559.00
559.00
37.05

Post -Development 100 - Year
Subbasin Hydrology
Page 5
Subbasin : SUB-03
Input Data
Area(ac)------------------------------------------------------------------------
45-30
Peak Rate Factor-----------------------------------------------------------
484-00
Weighted Curve Number-----------------------------------------------
84-92
Rain Gage ID .
Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Paved parking & roofs
13-69
B
98-00
> 75 % grass cover, Good
16-02
B
61-00
Future -Paved parking & roofs
15-59
B
98-00
Composite Area & Weighted CN
45-30
84-92
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 (ft)
Wp
= Wetted Perimeter (ft)
V =
Velocity (ft/sec)
Sf =
Slope (ft/ft)
n =
Manning's roughness
User -Defined TOC override (minutes): 5-00
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 7-50
Total Runoff (in)------------------------------------------------------------- 5-72
Peak Runoff (cfs)----------------------------------------------------------- 255-91
Weighted Curve Number----------------------------------------------- 84-92
Time of Concentration (days hh:mm:ss)------------------------ 0 00-05-00

Post -Development 100 - Year Page 6
Subbasin : SUB-03
6.5
6
5.5
5
4.5
4
E 3.5
M
3
FY
2.5
2
1.5
1
0.5
270
260
260
240
230
220
210
200
190
180
170
_ 160
150
140
0 130
120
110
100
90
80
70
60
50
40
30
20
10
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASINSUB-01
Page 7
Input Data
Area(ac)------------------------------------------------------------------------ 13.14
Peak Rate Factor----------------------------------------------------------- 484.00
Weighted Curve Number ----------------------------------------------- 70.54
Rain Gage ID----------------------------------------------------------------- Rain Gage-001
Composite Curve Number
Area
Soil
Curve
Soil/Surface Description
(acres)
Group
Number
Pasture, grassland, or range, Good
3.13
B
61.00
9.65
74.00
0.37
61.00
Composite Area & Weighted CN
13.15
70.54
Time of Concentration
Subarea
Subarea
Subarea
Sheet Flow Computations
A
B
C
Manning's Roughness :
.4
0.00
0.00
Flow Length (ft) :
100
0.00
0.00
Slope (%) :
.67
0.00
0.00
2 yr, 24 hr Rainfall (in) :
3.50
0.00
0.00
Velocity (ft/sec) :
0.05
0.00
0.00
Computed Flow Time (min) :
31.80
0.00
0.00
Total TOC (min) ..................31.80
Subbasin Runoff Results
Total Rainfall (in)------------------------------------------------------------ 7.50
Total Runoff (in)------------------------------------------------------------- 4.10
Peak Runoff (cfs)........................................................... 35.31
Weighted Curve Number ............................................... 70.54
Time of Concentration (days hh:mm:ss) ------------------------ 0 0031:48

Post -Development 100 - Year Page 8
Subbasin : UNDISTURBED-BASIN-SUB-01
7
6.5
6
5.5
5
4.5
4
3.5
3
2.6
2
1.5
1
0.5
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
Rainfall Intensity Graph
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
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
Subbasin : UNDISTURBED-BASIN-SUB-02
Page 9
Input Data
Area(ac)------------------------------------------------------------------------ 23-79
Peak Rate Factor----------------------------------------------------------- 484-00
Weighted Curve Number----------------------------------------------- 79-00
Rain Gage ID - Rain Gage-001
Composite Curve Number
Area Soil Curve
Soil/Surface Description (acres) Group Number
Woods, Fair 23-79 D 79-00
Composite Area & Weighted CN 23-79 79-00
Time of Concentration
Sheet Flow Computations
Manning's Roughness
Flow Length (ft)
Slope (%) :
2 yr, 24 hr Rainfall (in)
Velocity (ft/sec) :
Computed Flow Time (min) :
Shallow Concentrated Flow Computations
Flow Length (ft)
Slope (%) :
Surface Type :
Velocity (ft/sec)
Computed Flow Time (min) :
Total TOC (min)------------------36-96
Subbasin Runoff Results
Subarea Subarea Subarea
A B C
-4 0-00 0-00
100 0-00 0-00
9-5 0-00 0-00
3-50 0-00 0-00
0-15 0-00 0-00
11-01 0-00 0-00
Subarea Subarea Subarea
A B C
1370 0-00 0-00
-3 0-00 0-00
Unpaved Unpaved Unpaved
0-88 0-00 0-00
25-95 0-00 0-00
Total Rainfall (in)------------------------------------------------------------ 7-50
Total Runoff (in)------------------------------------------------------------- 5-04
Peak Runoff (cfs)----------------------------------------------------------- 73-04
Weighted Curve Number----------------------------------------------- 79-00
Time of Concentration (days hh:mm:ss)------------------------ 0 00-36-58

Post -Development 100 - Year Page 10
Subbasin : UNDISTURBED-BASIN-SUB-02
7
6.5
6
5.5
5
4.5
4
3.5
3
2.6
2
1.5
1
0.5
80
75
70
65
60
55
50
45
u 40
0
35
30
25
20
15
10
5
Rainfall Intensity Graph
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
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 11
Channel Input
SN Element Length Inlet Inlet
Outlet Outlet Total Average Shape
Height Width Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert
Invert Invert Drop
Slope
Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset
(ft) (ft) (ft)
(ft) (ft) (ft)
( % )
(ft) (ft) (cfs)
1 Link-02 50.00 555.00 0.00
554.90 1.60 0.10
02000 Rectangular
2000.5.000 0.0010 0.5000 0.5000 0.0000 0.00 No

Post -Development 100 - Year Page 12
Channel 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 Link-02 189.61 0 12:30 712.92 027 27.11 0.03 1.40 0.70 0.00

Post -Development 100 - Year Page 13
Pipe Input
SN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap
ID Invert Invert Invert Invert Drop Slope Shape Diameteror Width Roughness Losses Losses Losses Flow Gate
Elevation Offset Elevation Offset Height
(ft) (ft) (ft) (ft) (ft) (ft) ( % ) (in) (in) (cfs)
1 Outlet-Pipe-03 65.00 559.00 0.00 555.00 0.00 4.00 6.1500 CIRCULAR 42.000 42.000 0.0130 0.5000 0.5000 0.0000 0.00 No

Post -Development 100 - Year Page 14
No. of
Barrels

Post -Development 100 - Year Page 15
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-03 137.01 0 12:08 249.58 0.55 1424 0.08 3.50 1.00 45.00 SURCHARGED

Post -Development 100 - Year Page 16
Storage Nodes
Storage Node : Pond-03
Input Data
Invert Elevation (ft)--------------------------------------------------------------------
559-00
Max (Rim) Elevation (ft)------------------------------------------------------------
571-50
Max (Rim) Offset (ft)-----------------------------------------------------------------
12-50
Initial Water Elevation (ft)----------------------------------------------------------
565-00
Initial Water Depth (ft)---------------------------------------------------------------
6-00
Ponded Area (ft) -----------------------------------------------------------------------
0-00
Evaporation Loss-----------------------------------------------------------------------
0-00
Outflow Weirs
SIN Element
Weir Flap
Crest
Crest
Length
Weir Total Discharge
ID
Type Gate
Elevation
Offset
Height Coefficient
(ft)
(ft)
(ft)
(ft)
1 Spillway-03
Trapezoidal No
571-00
12-00
50-00
0-50 3-33
2 Weir-03A
Rectangular No
566-80
7-80
5-00
120 3-33
Outflow Orifices
SIN 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-03 Bottom
Rectangular No
60-00
60-00
568-00 0-63
2 WQ-Orifice-03 Side
CIRCULAR
No
4-00
565-00 0-61
Output Summary Results
Peak Inflow (cfs)------------------------------------------------------------------------
254-07
Peak Lateral Inflow (cfs)------------------------------------------------------------
254-07
Peak Outflow (cfs)---------------------------------------------------------------------
137-62
Peak Exfiltration Flow Rate (cfm)----------------------------------------------
0-00
Max HGL Elevation Attained (ft)------------------------------------------------
570-05
Max HGL Depth Attained (ft)-----------------------------------------------------
11-05
Average HGL Elevation Attained (ft)-----------------------------------------
566-53
Average HGL Depth Attained (ft)----------------------------------------------
7-53
Time of Max HGL Occurrence (days hh:mm)---------------------------
0 1220
Total Exfiltration Volume (1000-ft3)-------------------------------------------
0-000
Total Flooded Volume (ac-in) -
0
Total Time Flooded (min)
0
Total Retention Time (sec) --------------------------------------------------------
0-00

25-YR
CAPACITY

HEC-22
Energy Grade Line Computations
Struct.
ID
Q
(cfs)
EGLo
(ft)
HGLo
(ft)
Total Pipe
Loss
(ft)
EGU
(ft)
HGU
(ft)
Ea
(ft)
EGLa
(ft)
Surface Elev.
(ft)
2 569.31
569.31
569.92
0.37 572.75 571.20 7.5 573.37 580.59
1
141.9
572.38
570.86
3
133.1
573.80
572.71
0.70
574.50
573.41
8.6
575.25
580.87
4
78.2
575.49
574.89
0.18
575.67
575.06
9.2
576.17
580.61
5
77.9
576.41
575.81
0.08
576.49
575.89
9.9
576.99
580.63
6
78.2
577.23
576.63
0.29
577.52
576.92
10.1
577.71
579.77
7
64.3
577.87
577.46
0.32
578.19
577.78
10.0
578.38
580.96
8
64.3
578.54
578.14
0.06
578.60
578.19
10.3
578.84
581.33
20
8.4
578.98
578.63
0.23
579.21
578.86
9.3
579.39
581.33
21
7.9
579.51
579.20
0.14
579.66
579.34
9.5
579.80
581.61
22
5.1
579.86
579.72
0.24
580.09
579.96
2.5
580.13
582.44
23
4.2
580.16
580.07
0.16
580.32
580.23
1.8
580.38
583.28
24
2.0
580.38
580.36
0.01
580.40
580.38
1.4
580.41
583.42
25
1.9
579.81
579.79
0.01
579.82
579.80
9.3
579.83
581.76
9
55.8
578.96
578.66
0.16
579.12
578.82
6.7
579.23
584.35
10
41.1
579.34
579.06
581.83
578.61
4.4
581.83
593.38
11
40.1
581.93
581.66
585.07
581.89
4.4
585.07
597.70
12
40.0
585.27
584.77
0.85
586.12
585.62
3.8
586.30
596.59
13
36.9
586.47
586.05
588.17
586.37
3.3
588.17
595.03
14
31.4
588.29
587.98
0.23
588.52
588.21
3.2
589.08
595.95
15
16.0
589.15
588.96
591.22
590.29
1.9
591.22
600.79
16
15.9
591.32
591.08
592.03
591.08
2.0
592.03
602.46
17
6.0
594.39
593.12
599.47
598.20
1.8
599.47
606.49
18
4.9
599.48
599.44
600.68
600.00
1.3
600.68
609.27
19
1.6
600.69
600.67
601.41
600.80
0.9
601.41
609.26
38
8.2
592.09
591.94
592.76
592.35
1.8
593.09
596.81
39
7.0
593.12
593.03
593.12
592.75
1.6
593.12
596.81
14
13.8
589.20
588.90
0.14
589.34
589.03
3.2
589.49
596.11
34
9.1
589.54
589.41
0.25
589.79
589.66
2.1
589.90
595.08
49
4.8
590.00
589.76
0.73
590.73
590.49
1.9
590.84
593.03
33
1.8
590.85
590.82
591.24
590.99
0.8
591.26
595.11
35
4.0
591.24
589.99
593.79
592.54
1.7
593.79
596.73
36
2.9
593.83
593.74
597.72
596.68
1.5
597.72
600.70
50
3.1
588.20
588.12
588.39
588.00
1.0
588.39
595.03
53
1.8
586.31
586.29
0.01
586.32
586.30
3.5
586.35
596.60
9
13.9
579.25
579.19
0.02
579.27
579.21
6.0
579.31
585.71
26
10.7
579.32
579.28
0.04
579.36
579.32
4.5
579.37
580.63
28
4.6
579.39
579.35
0.05
579.43
579.40
3.8
579.44
581.28
29
3.2
579.46
579.41
0.10
579.56
579.51
3.3
579.59
582.90
30
1.6
579.60
579.58
0.03
579.63
579.62
2.6
579.63
581.49
31
1.8
579.38
579.36
587.64
586.68
1.2
587.64
593.45
51
10.2
577.77
577.61
0.14
577.92
577.75
4.4
577.97
579.46
52
7.1
578.01
577.93
0.17
578.18
578.10
3.7
578.22
581.50
48
3.3
577.73
577.68
0.03
577.76
577.70
6.0
577.78
579.77
43
6.4
573.45
573.24
0.41
573.86
573.65
3.4
573.93
577.47
44
4.5
573.97
573.87
0.27
574.24
574.14
2.2
574.28
578.97
45
3.3
574.33
574.21
0.40
574.72
574.61
1.2
574.77
580.47
46
2.5
574.80
574.73
575.96
575.58
1.0
576.02
579.58
47
0.8
576.02
576.01
577.24
577.05
0.5
577.24
581.33
40
3.4
573.39
573.33
0.10
573.491
573.431
6.4
573.52
581.89
41
1 2.7
573.551
573.47
0.271
573.821
573.74
5.2
573.89
584.30
42
1 1.31
573.891
573.881
0.051
573.951
573.931
4.0
573.97
586.29
Pi THOMAS s HUTTON
Z: �27842�27842.000Z�Engineering�Calculations and Reports�Storm Water�HEC-22�2021-06-01�Copy of HEC-ZZ Reporting

HEC-22
Storm Drain Computations
Structure ID
Length
(ft)
Drainage
Area
(ac)
Runoff
Coeff "C"
Tc
(min)
Rain "I"
(in/hr)
Runoff
1.Q"
(cfs)
Known Q
(cfs)
Total Q
(cfs)
Pipe Dia.
(in)
Velocity
Design
(ft/s)
Invert Elevation
Slope
From To
U/S I D/S
2 1 74 0.01 0.55 5 7.32 75.5 141.91 54 10.0 565.87 565.501 0q5O
50%
12 152 0.04 0.55 5 7.38� 66.8 55.0 133.1 54 10.0 566.64 565.87
4 3 60 0.09 0.55 5 7.41 66.8 78.2 48 8.9 566.94 566.64
Pi THOMAS a HUTTON
Z: �27842�27842.0002�Engineering�Calculations and Reports�Storm Water�HEC-22�2021-06-01�Copy of HEC-22 Reporting

4 IN/HR
INLET
SPREAD

HEC-22
Inlet Capacity Results
Structure
Q=CIA/Kc
(cfs)
Known
Q
(cfs)
Longitudinal
Slope
SL
(ft/ft)
Cross
Slope
Sx
(ft/ft)
Cross
Slope
SW
(ft/ft)
Prev.
Bypass
Flow
(cfs)
Total
Gutter
Flow
(cfs)
Depth
d
(ft)
Gutter
Width
(ft)
Spread
T
(ft)
Inlet Type
Grate
Length
(in)
Grate
Width
(in)
Intercept
Flow
Qi
(cfs)
Bypass
Flow
Qb
(cfs)
Bypass
Structure
Remark
30 0.8
0.01
0.33
0.33
0.33
0.7
0.8 0.4 0.0 1.1 Grate inlet 23.8 23.8
0.4
0.6
0.4
0.9
29
28
0.7
0.01
1.5
0.41
0.0
1.3
Grate inlet
23.8
23.8
27
27
2.3
N/A
1.4
3.7
0.71
0.0
2.1
Grate inlet
23.8
23.8
3.7
33
0.9
0.01
0.33
0.9
0.4
0.0
1.1
Grate inlet
23.8
23.8
0.4
0.5
49
31
0.9
0.01
0.33
0.9
0.4
0.0
1.1
Grate inlet
23.8
23.8
0.4
0.5
27
49
1.5
0.01
0.33
0.5
2.0
0.5
0.0
1.5
Grate inlet
23.8
23.8
0.7
1.3
35
35
1 0.3
N/A
0.33
2.2
2.5
0.5
0.0
1.6
Grate inlet
23.8
23.8
2.5
36
0.6
0.01
0.33
0.9
1.4
0.4
0.0
1.3
Grate inlet
23.8
23.8
0.6
0.9
35
37
1.4
0.01
0.33
1.4
0.4
0.0
1.3
Grate inlet
23.8
23.8
0.61
0.9
36
47
0.4
0.01
0.33
0.4
0.3
0.0
0.8
Grate inlet
23.8
23.8
0.2
0.2
46
46
0.9
0.01
0.33
0.2
1.1
0.4
0.0
1.2
Grate inlet
23.8
23.8
0.4
0.6
45
45
0.4
0.011
0.33
0.6
1.01
0.4
0.0
1.2
Grate inlet
23.81
23.8
0.4
0.6
44
44
1 0.6
0.01
0.33
0.6
1.2
0.4
0.01
1.3
Grate inlet
23.8
23.8
0.5
0.7
43
43
1.0
0.01
0.33
0.7
1.8
0.5
0.0
1.4
Grate inlet
23.8
23.8
0.6
1.1
2
42
0.6
N/A
0.33
0.5
1.1
0.3
0.0
1.0
Grate inlet
23.8
23.8
1.1
41
0.7
0.01
0.33
0.2
0.9
0.4
0.0
1.1
Grate inlet
23.8
23.8
0.4
0.5
42
40
0.4
0.01
0.33
0.4
0.3
0.0
0.8
Grate inlet
23.8
23.8
0.2
0.2
41
39
0.9
0.011
0.02
0.04
0.91
0.2
2.0
5.7
Combination
35.5
23.6
0.7
0.2
38
1 0.6
0.01
0.02
0.04
0.2
0.8
0.2
2.01
5.4
Combination
35.5
23.6
0.6
0.1
19
0.8
0.02
0.02
0.04
0.8
0.1
2.0
4.4
Combination
35.5
23.6
0.7
0.1
55
18
1.6
0.02
0.02
0.041
1.6
0.2
2.0
6.1
Combination
35.5
23.6
1.2
0.4
17
17
0.6
0.02
0.02
0.04
0.4
1.0
0.2
2.0
5.3
Combination
35.5
23.6
0.8
0.2
16
16
0.9
0.03
0.02
0.04
0.2
1.1
0.1
2.0
5.0
Combination
35.5
23.6
0.9
0.2
38
14
1.0
0.021
0.02
0.04
1.01
0.2
2.0
5.3
Combination
35.51
23.6
0.8
0.2
13
34
1 0.9
0.02
0.02
0.04
0.4
1.3
0.2
2.0
6.0
Combination
35.5
23.6
1.0
0.3
50
13
1.4
N/A
0.02
0.04
0.3
1.7
0.2
2.0
5.3
Combination
71.0
23.6
1.7
12
0.9
0.01
0.02
0.041
0.9
0.2
2.0
5.4
Combination
35.5
23.6
0.7
0.2
13
11
0.3
0.02
0.02
0.04
0.3
0.1
2.0
2.9
Combination
35.5
23.6
0.3
0.0
10
10
0.6
0.05
0.02
0.04
0.0
0.6
0.1
2.0
3.1
Combination
35.5
23.6
0.6
0.019
9
0.9
0.051
0.02
0.04
0.0
0.91
0.1
2.0
4.0
Combination
35.51
23.6
0.8
0.1
8
26
1 1.7
0.05
0.02
0.04
1.7
0.2
2.0
5.3
Combination
35.5
23.6
1.3
0.4
20
24
1.0
0.01
0.02
0.04
1.0
0.2
2.0
6.2
Combination
35.5
23.61
0.8
0.2
25
23
1.1
0.01
0.02
0.041
1.1
0.2
2.01
6.5
Combination
35.5
23.6
0.8
0.3
22
22
0.5
0.01
0.02
0.04
0.3
0.7
0.2
2.0
5.4
Combination
35.5
23.6
0.6
0.1
21
21
0.5
0.01
0.02
0.04
0.1
0.6
0.1
2.0
5.0
Combination
35.5
23.6
0.5
0.1
20
20
0.2
N/Al
0.02
0.04
0.4
0.71
0.1
2.0
3.1
Combination
35.5
23.6
0.7
8
1 0.5
N/A
0.02
0.04
0.1
0.51
0.1
2.0
2.4
Combination
35.51
23.6
0.5
7
0.1
0.01
0.02
0.04
0.1
0.1
2.0
1.8
Combination
35.5
23.6
0.1
6
6
0.8
N/A
0.02
0.04
0.9
1.7
0.2
2.0
5.4
Combination
71.0
23.6
1.7
5
0.0
0.01
0.02
0.04
0.0
0.1
2.0
1.4
Combination
35.51
23.61
0.01
16
0i THOMAS - HUTTON
Z:127842127842.00021EngineeringlCalculations and ReportslStorm WaterIHEC-2212021-09-141Copy of HEC-22 Reporting

HEC-22
Inlet Capacity Results
Structure
Q=CIA/Kc
(cfs)
Known
Q
(cfs)
Longitudinal
Slope
SL
(ft/ft)
Cross
Slope
Sx
(ft/ft)
Cross
Slope
SW
(ft/ft)
Prev.
Bypass
Flow
(cfs)
Total
Gutter
Flow
(cfs)
Depth
d
(ft)
Gutter
Width
(ft)
Spread
T
(ft)
Inlet Type
Grate
Length
(in)
Grate
Width
(in)
Intercept
Flow
Qi
(cfs)
Bypass
Flow
Qb
(cfs)
Bypass
Structure
Remark
4 0.2
F
0.01
0.02
0.04
0.2
0.1
2.0
3.0
Combination
35.5
23.6
0.2
0.0
48
3
0.1
0.02
0.02
0.04
0.1
0.1
2.0
1.5
Combination
35.5
23.6
0.1
25
0.9
0.01
0.02
0.04
0.2
1.2
0.2
2.0
6.7
Combination
35.5
23.6
0.9
0.3
48
50
1.5
N/A
0.02
0.04
0.5
2.0
0.2
2.0
6.2
Combination
71.0
23.6
2.0
2
0.0
N/A
0.33
1.1
1.1
0.3
0.0
1.0
Grate inlet
23.8
23.8
1.1
48
1.6
N/Al
0.02
0.041
0.3
1.91
0.2
2.01
5.9
Combination
71.0
23.61
1.9
29
0.8
0.01
0.33
0.4
1.2
0.4
0.0
1.3
Grate inlet
23.8
23.8
0.5
0.7
28
15
0.1
0.03
0.02
0.04
0.1
0.1
2.0
1.4
Combination
28.0
18.0
0.1
14
52
0.4
0.01
0.33
0.4
0.3
0.0
0.8
Grate inlet
23.8
23.8
0.2
0.2
51
51
1.0
0.01
0.33
0.5
1.5
0.4
0.0
1.3
Grate inlet
23.8
23.8
0.6
0.9
6
53
0.9
0.01
0.02
0.04
0.9
0.2
2.0
5.7
Combination
1 35.51
23.6
0.7
0.2
50
54
0.61
1 0.011
0.33
0.6
0.3
0.0
0.9
Grate inlet
1 23.81
23.8
0.3
0.3
51
55
1.51
1 0.031
0.021
0.041
0.11
1.61
0.21
2.01
6.1
Combination
1 35.51
23.61
1.21
0.4134
0i THOMAS - HUTTON
Z:127842127842.00021EngineeringlCalculations and ReportslStorm WaterIHEC-2212021-09-141Copy of HEC-22 Reporting

APPENDIX I ITEM 6
STORM DRAIN PIPE
MAXIMUM CAPACITY TABLE
(1) PIPE SIZE
(2) MAXIMUM CAPACITY
12"
6
15"
9
18"
13
24"
25
30"
43
36"
4
42"
90
48"
120
54"
160
60"
200
66"
250
(1) CONCRETE PIPE
(2) CAPACITY (c.f...) BASED ON INLET CONTROL
FOR MAXIMUM DEPTH IN STANDARD CATCH BASIN
6/90

STORMWATER MANAGEMENT REPORT
CRESSWIND WESLEY CHAPEL - PHASE 02
APPENDIX F
WATER QUALITY
CALCULATIONS
27842.0002
Fq THOMAS Sc HUTTON

Water Quality Calculations
Cresswind - Wesley Chapel
Project No. 27842.002
WET POND 03
Project/Drainage Area: 45.30 Acres Required Water Quality Volume: 105,187 Cubic Feet
Impervious Area: 29.68 Acres (Project Area (Acres) X 43,560 SF X 1"/12 = Required Cubic Feet Volume)
65.5% Percent Impervious Runoff Coeifficient: Rv= .05+0.9 (1) = 0.64
(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: I 0.609 CFS Required Orifice Size: 4.00 Drawdown Time (Hours): 1 72.41
Water Quality Elevation
Elev.
Area
Storage
(ft)
(sf)
(cu. ft)
565.00
48,889.00
0.00
571.00
72,687.00
364,728.00
Elevation
Pond Depth
Storage
(ft)
(ft)
(cu. ft)
565.00
0.00
0.00
566.73
1.73
105,186.51
571.00
6.00
364,728.00
Average Depth Calculation
Vpp Designed @ Elevation
565.00
190,429.00
Permanent Pool SA Designed @ Elev
565.00
39,712.00
Area of wet pond at the bottom of the shelf
36,949.00
Dmax over shelf
0.50
Perimeter of Permanent Pool
1,055.00
Width of submerged part of shelf
3.00
Volume over the shelf only
791.25
Average Depth
5.13
SA/DA Method
Drainage Area
45.30
acres
Table value
1.65
Surface Area Required
32,558.92
square feet
Orifice Flow Calculation
Q=CdA*sgrt(2gh)
Cd =
0.62
(Sharp Orifice)
A =
0.087
sf
g =
32.174
ft/s2
h =
1.73
ft
Q =
0.403
1cfs
VPP-Vshelf
Davg =
Abottomo f shelf
Where: Davy = Average depth in feet
VPP = Total volume of permanent pool (feet')
Vshelf = Volume over the shelf only (feet') - see below
Abottom of shelf = Area of wet pond at the bottom of the shelf (feet')
Vshelf = 0.5 * Depthmax over shelf* Perimeterperm pool* Widthsul,merged part of shelf
Where: Dmax over shelf = Depth of water at the deep side of the shelf as
measured at permanent pool (feet)
Perimeterpermanent pool = Perimeter of permanent pool at the bottom of the
shelf (feet)
Widthsubmerged pan of shelf = Width from the deep side to the dry side of the
shelf as measured at permanent pool (feet)
Table 1: Piedmont and Mountain 5AIDA Table (Adapted from Driscoll, 1986)
10%
0.51
0.43
0.37
0.30
0.27
0.25
20%
0.84
0.69
0.61
0.51
0.44
0.40
30%
1.17
0.94
0.84
0.72
0.61
0.56
40%
1.51
1.24
1.09
0.91
0.78
0.71
50%
1.79
1.51
1.31
1.13
0.95
0.87
60%
2.09
1.77
1.49
1.31
1.12
1 M
70%
2.51
2.09
1.80
1.56
1.34
1.17
80%
2.92
2.41
2.07
1.82
1.62
1.40
90%
3.25
2.64
2.31
2.04
1.84
1.59
100%
3.55
2.79
2.52
2.34
2.04
1.75

FOREBAY 01 VOLUME
CONTOUR ELEV CONTOUR AREA
(SF)
559
1,761
560
2,102
561
2,474
562
2,875
563
3,306
564
3,766
564.5
4,128
565
4,647
FOREBAY 02 VOLUME
CONTOUR ELEV CONTOUR AREA
(SF)
559
560
561
562
563
564
564.5
565
1,074
1,368
1,692
2,045
2,428
2,840
3,137
3,667
PERMANENT POOL VOLUME
CONTOUR ELEV
559
560
561
562
563
564
564.5
565
CONTOUR AREA
(SF)
25710
27625
29,582
31,581
33,618
35,690
36,949
39,712
TEMPORARY PONDING ZONE
Stage Storage Calculations
Cresswind - Wesley Chapel
Project No. 27842.0002
WET POND 03
DEPTH (FT)
N/A
1
1
1
1
1
0.5
0.5
DEPTH (FT)
N/A
1.00
1.00
1.00
1.00
1.00
0.50
0.50
INC. VOL. AVG.
END (CU. FT.)
N/A
1,932
2,288
2,674
3,090
3,536
1,973
2,194
INC. VOL. AVG.
END (CU. FT.)
N/A
1,221
1,530
1,869
2,237
2,634
1,494
1,701
CUM. VOL. AVG. END
(CU. FT.)
0
1,932
4,220
6,894
9,984
13,520
15,493
17,687
CUM. VOL. AVG. END
(CU. FT.)
0
1,221
2,751
4,620
6,857
9,491
10,985
12,686
TOTAL FOREBAY VOLUME: I 30,373 CU. FT.
PERCENTAGE OF PERMANENT POOL VOLUME:1 15.95
DEPTH (FT)
N/A
1
1
1
1
1
0.5
0.5
INC. VOL. AVG.
END (CU. FT.)
N/A
26,667
28,603
30,582
32,599
34,654
18,159
19,165
CUM. VOL. AVG. END
(CU. FT.)
0
26,667
55,270
85,852
118,451
15 3,10 5
171,264
190,429
PERMANENT POOL VOLUME: I 190,429 CU.FT
CONTOUR AREA
INC. VOL. AVG.
CUM. VOL. AVG. END
CONTOUR ELEV
DEPTH (FT)
(SF)
END (CU. FT.)
(CU. FT.)
565
48,889
N/A
N/A
0
565.5
52,395
0.5
25,321
25,321
566
54,139
0.5
26,634
51,955
567
57,738
1
55,939
107,894
568
61,391
1
59,565
167,458
569
65,091
1
63,241
230,699
570
68,845
1
66,968
297,667
571
72,687
1
70,766
368,433
TEMPORARY PONDING ZONE VOLUME:1 368,433 CU. FT.

Cresswind Wesley Chapel - Phase 02 Job: J-27842.0002
T z KH Wesley Chapel, LLC Date: 2/18/21
HP Thomas & Hutton Engineering Co. Revised:
~FEaµ
Anti -Flotation Design Considerations By: MSK
ANTI -FLOTATION DESIGN CONSIDERATIONS FOR:
Wet Pond 02
CONTROL STUCTURE ELEVATIONS
Top Structure Elevation: 570.20
Bottom Structure Elevation: 558.80
CONTROL STRUCTURE FLOTATION
Buoyant Force
Calculate submerged volume:
Vs = (As x H,$)
Where:
VS = Submerged volume (cf)
L,s = Length of control structure (ft) = 6.00 ft
W,s = Width of Control structure (ft) = 6.00 ft
A,s- Cross -sectional area of control structure (ft) = 36.00 ft
H,s = Height of control structure (ft) = 11.40 ft
Solve equation for Vs:
VS = (A,s x H,$) = 410.40 cf
Calculate buoyant force:
Fb = Vs x 7w.W,
Where:
Fb = buoyant force (lbf)
y,,,, = Specific weight of water = 62.40 lbf/cf
Fb = 25,609 lbf
Z:\27842\27842.0002\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0002 - Wet Pond 03 - Anti Flotation
Design Calculations Pagel of 3

Cresswind Wesley Chapel - Phase 02 Job: J-27842.0002
T z KH Wesley Chapel, LLC Date: 2/18/21
HP Thomas & Hutton Engineering Co. Revised:
~FEaµ
Anti -Flotation Design Considerations By: MSK
Downward Force
Calculate Downward Force of Control Structure
Fdcs = (• cs - Vw& - Vorj&c) X Yconcrete
Where:
WteS =
Weight of control structure (lbs)
Yconcrete =
Specific weight of concrete
= 140.00 lbf/cf
Acs =
Cross -sectional area of control structure (ft)
= 36.00 ft
Hcs =
Height of control structure (ft)
= 11.40 ft
Tcs =
Wall thickness of control structure (ft)
= 0.50 ft
Vcs =
Volume of control structure (cf)
= 125.40 cf
Wu,eu =
Width of weir (ft)
= 5.00 ft
Hu,eu
= Height of weir opening (ft)
= 1.20 ft
Au,eu
= Area of weir opening(ft)
= 6.00 sf
Vu,e;r
= Volume of weir
= 3.00 cf
DIAorifice
= Diameter of orifice opening (in)
= 5.00 in
Aorifice
= Area of orifice opening (sf)
= 0.136 sf
Vorifice
= Volume of orifice opening (sf)
= 0.068 cf
FdC3 = 17,126 lbf
Size Anti -Flotation Footing to Resist Bouyant Force
FdeS + Fdft > Fb
Fdft = (Lb X Wb X Db) X Yconcrete
Where:
FdeS =
downward force of control structure (lbf) =
17126 lbf
Fb =
buoyant force (lbf) =
25609 lbf
Yconcrete =
Specific weight of concrete =
77.60 lbf/cf
Lb
= Length of Concrete Block =
12.00 ft
Wb =
Width of Concrete Block =
12.00 ft
Db
= Depth of Concrete Block =
12.00 in
Fdft =
downward force of anti -flotation footing (lbf) =
11174 lbf
Z:\27842\27842.0002\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0002 - Wet Pond 03 - Anti Flotation
Design Calculations Page 2 of 3

Cresswind Wesley Chapel - Phase 02
KH Wesley Chapel, LLC
Thomas & Hutton Engineering Co.
Job: J-27842.0002
Date: 2/18/21
Revised:
Anti -Flotation Design Considerations By: MSK
Fd, + Fdtt = 28301 lbf > Fb = 25609 lbf _
Factor of Safety
Confirm anti -flotation block is sized for minimum factor of safety (F,) of 1.10.
Fs = (Fdcs + Fdrt)/Fb
1.11 > 1.10 -
Z:\27842\27842.0002\Engineering\Calculations and Reports\Storm Water\Anti Flotation\27842.0002 - Wet Pond 03 - Anti Flotation
Design Calculations Page 3 of 3