SW6230401_Design Calculations Full Set_20230707

PHALANX CROSSFIT
Storm Water and Erosion & Sedimentation Control Calculations
REVISIONS PER 5/19/23 COMMENTS FROM DEMLR STORMWATER PROGRAM
�1^ .i h5 '(iV
..' S6� ( F17 j ,7 6 ." " 2g yf.,t
sy(( ::.44, 1t hll 27 1r7)® • G Y '.20 L. i' )'J7 $79
47•1 � 0 oii� * 57 76 /77 ,W.317°+ t311:. /fi ,1.
+oM.__/ A1101L 51
�tF�J 4. �. ,�_r. ,.
„ r, �Io9 y 7.560; S7 �. 1 ♦- . '61
�. U4.80•JJ4,�P 11t\ 117 1s1.:Mt,.ii i77 68��_�!!!• .5 'yy/yy o /7111
/ , F J.`C` 11 •�. f ms r. .M •9 ��}1�'L 88 ,00
� �7 71 1 ? .��� f F`� 1a 4� �V
4 A, 2571 (. . a, (,t, �``MYI'J
� ti .. �?7g�y � may,18�E�7g7f ��119.1 37
fir tli 128' 158
\ 4/4flit , ii.. ,'(/2,4s 95N, " ''''43 3n
N7n 3 2687. , } ./63.'511 .571
.A f •
fit. it 521
k 4044 Ste 2.(. 7-,.26 g'
h15 if
�A` 1708 � i5
Owner:
Phalanx Fitness, LLC
359 Sunridge Drive
Cameron, NC 28326

Phalanx Crossfit 2
The certification shown below applies only to the items listed on this 'Table of Contents'
Table of Contents
Rip Rap Outlet Apron 02 2 Pages
Rip Rap Outlet Apron 03 2 Pages
Rip Rap Outlet Apron 04 2 Pages
Pond Stage-Storage Below Pool - Forebay 1 Page
Pond Stage-Storage Below Pool - Main Pool 1 Page
Driveway Culvert Drainage Area Map 1 Page
Surface Area and Depth Required for Main Pool 1 Page
HILLIARD
ENGINEERING ,, s,N CAR°,
ESSiQ•.7
�-57
Author:Jarrod E. Hilliard, PE, CFM - E A
•
PO Box 249 Sanford, NC 27331 _ t 35 5
•
[phone] 9A.O/G N. : Po'
NC License No. P-0836
Date: 5/22/23

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 5/19/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 02 -SCM Outlet
Total Drainage Area (acres) 0.76
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter_ it is classified minimum tailwater condition.
If it is greater than half the pipe diameter_ it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable Hood stage elevations
show otherwise.
Pipe diam., Do (in.) 3
Tailwater depth (in.) 0
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 0.56
Velocity (ft./s) 16.5
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron_
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.2
Minimum apron length, La (ft.) 7
Apron width at pipe outlet (ft.) 0.75 0.75
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 7.25 0.25
Step 4. Determine the maximum stone diameter:
dmax = 1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.3 0
Step 5. Deternune the apron thickness:
Apron thickness = 1.5 x dr,,
Minimum TW Maximum TW
Apron Thickness(ft.) 0.45 0
Step 6. Fit the riprap apron to the site by making it level for the minimunn
length, La. from Figure 8.06a or Figure 8.06b_ Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfills exist at
pipe outlets or flows are excessive. a plunge pool should be considered, see
page 8.06.8_

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 1/11/2023
Checked By: JEH 1/11/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 03 -Swale 01B Outlet
Total Drainage Area (acres) 1 .57
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Equiv. Outlet diam., Do (in.) 18
Tailwater depth (in.) 0.25
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 3.72
Velocity (ft./s) 2.23
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.35
Minimum apron length, La (ft.) 9
Apron width at pipe outlet (ft.) 4.5 4.5
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 10.5 1.5
Step 4. Determine the maximum stone diameter:
d�*'ax 1.5 x dF0
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.525 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d.,,,
Minimum TW Maximum TW
Apron Thickness(ft.) 0.7875 0
Step 6. Fit the riprap apron to the site by making it level for the nunimuin
length, La_ from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along chaiumel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive, a plunge pool should be considered. see
page 8.06.8_

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 11/29/2022
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 04 -Swale 01A Outlet
Total Drainage Area (acres) 0.55
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter_ it is classified minimum tailwater condition.
If it is greater than half the pipe diameter_ it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable Hood stage elevations
show otherwise.
Equiv. Outlet diam., Do (in.) 18
Tailwater depth (in.) 0.25
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 1 .3
Velocity (ft./s) 0.93
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron_
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.35
Minimum apron length, La (ft.) 9
Apron width at pipe outlet (ft.) 4.5 4.5
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 10.5 1.5
Step 4. Determine the maximum stone diameter:
dmax = 1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.525 0
Step 5. Deternune the apron thickness:
Apron thickness = 1.5 x dr,
Minimum TW Maximum TW
Apron Thickness(ft.) 0.7875 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length, La. from Figure 8.06a or Figure 8.06b_ Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfills exist at
pipe outlets or flows are excessive. a plunge pool should be considered, see
page 8.06.8_

WET POND STAGE-STORAGE BELOW PERMANENT POOL
FOREBAY ONLY
WET POND 01
Project# PHALANX CROSSFIT
Date: 5/19/2023
Evaluation By: JEH
OBJECTIVE: Determine volumes below permanent pool
GIVEN:
Location: Spout Springs,NC
Watershed Area: 0.76
Accum.Storage(cu.
Contour(ft-MSL): Area(sf) Inc.Vol(cu.ft) ft) Stage(ft)
364.50 0,000 0,000 0,000 0.00
368.0 0,125 0,219 0,219 3.50
368.5 0,201 0,082 0,300 4.00 ACTUAL AVAILABLE STORAGE BELOW
369.0 0,297 0,125 0,425 4.50 PERMANENT POOL
370.0 0,540 0,419 0,843 5.50
370.5 0,690 0,308 1,151 6.00
MAIN POOL VOLUME: 6,128 cf % MAIN POOL: 18.78%
AVG.DEPTH MAIN POOL: 3.01 ft
364.50 IS TOP OF SEDIMENT STORAGE IN THE FOREBAY
TOTAL VOLUME BELOW PERMANENT POOL
Contour(ft-MSL): Area(sf)
364.5 165
368.0 1,235
368.5 1,480
369.0 1,754
370.0 2,376
370.5 2,728
2,038 IS SURFACE AREA OF THE MAIN PERMANENT POOL

WET POND STAGE-STORAGE BELOW PERMANENT POOL
MAIN POOL ONLY
WET POND 01
Project# PHALANX CROSSFIT
Date: 5/19/2023
Evaluation By: JEH
OBJECTIVE: Determine volumes below permanent pool
GIVEN:
Location: Spout Springs, NC
Watershed Area: 0.76
Accum.Storage
Contour(ft-MSL): Area(sf) Inc.Vol(cu.ft) (cu.ft) Depth(ft)
364.50 0,165 0,000 0,000 0.00
368.00 1,110 2,231 2,231 3.50
368.50 1,279 0,597 2,829 4.00 ACTUAL AVAILABLE STORAGE BELOW
369.00 1,457 0,684 3,513 4.50 PERMANENT POOL
370.00 1,836 1,647 5,159 5.50
370.50 2,038 0,969 6,128 6.00

\ SS,-
/
''N. •
\ •� / /
, */
,\ �
N N
-,
/
'N •\
i 'N' ‘‘,
.N N,N
N
N
N
Ns
/
% /
i / / /
-/ ,,,,,,,,,,,,,,,,,,,,..
silo_
a \/.
N
4 „ ....../ \/
" ./'
INLET DRAINAGE AREA:
•••. DA = 12.37 acres i t `N
°
f 125 = 8.75 in/hr / NNN
.. '''<
• I
c =
0.5 (Business: Neighborhood Areas) vim`. - '
Q25: 54.12 cfs
� � /� PLe98
' ORA60909 AREA map,
:::,,SF
AC
4, IMPERNO 9AREC) 4di4 `
] SF(.]46AC)
o r „�mc. �a.,� ,
,:, ,,,,,,,,,,N ' r . 010=2 36 oft SWALE 01A .„.
s/ 4 24020 SF pppyyy 7// 't
i, OSS AC „''oF B .;
I� R OUS EA: i/ d
aa8gp4 ] 2635E(O 006AC) /
/ I / ,,e,T.ro BB%pmiwrs I
�CIIIIIaR 4 9[ /% f K 'Nmrrtlp (-]%abpel
•
WET PO'°N'D Pis� £ . =
` ,," ,. •• :
PHALANX CROSSFIT
, ( '''' \:\\- '' - ititt• \''�'� s7�sA� DRIVEWAY CULVERT
`-�1 ��4*.-14*.44''i"ia....,:4
' :-0 ` ' DRAINAGE AREA MAP
„, S

PHALANX CROSSFIT
SURFACE AREA AND DEPTH REQUIRED FOR MAIN POOL
EQUATION 2
WET POND 01
TABLE 1 PIEDMONT AND MOUNTAIN SA/DA TABLE TABLE 1 PIEDMONT AND MOUNTAIN SA/DA T
INTERPOLATION (3 ft) INTERPOLATION (4 ft)
Known Lower Percent Impervious: 80 Known Lower Percent Impervious: 80
Known Upper Percent Impervious: 90 Known Upper Percent Impervious: 90
Known Lower SA/DA: 2.92 Known Lower SA/DA: 2.41
Known Upper SA/DA: 3.25 Known Upper SA/DA: 2.64
Computed Impervious: 88.00 Computed Impervious: 88.00
Unknown Target SA/DA: 3.18 Unknown Target SA/DA: 2.59
TABLE 1 PIEDMONT AND MOUNTAIN SA/DA TABLE
INTERPOLATION (Avg. Depth of Permanent Pool)
Known Lower Average Depth: 3
Known Upper Average Depth: 4
Known Lower SA/DA: 2.92
Known Upper SA/DA: 2.41
Computed Depth: 3.01
Unknown Target SA/DA: 2.91
Min.Surface Area Required for Main Pool Area:
SA/DA: 2.91
Drainage Area to SCM: 32,944 sf
Min. Surface Area Req'd: 960 sf
Surface Area Provided: 1,965 sf
Main Pool Volume: 6,128 cf
Main Pool Surface Area: 2,038 sf
Main Pool Ave. Depth: 3.01

PHALANX CROSSFIT
Storm Water and Erosion & Sedimentation Control Calculations
-.�ip�r 7.' .\., .-. y�+.� ,lea ur—�
w . i-,!1'.„
'Ire
`i. l `., � + i-- �, try..• �45 ,
,c` a .` J s�E . r 4 1 r ," ns.. . e
4 o n 1 s r , L e
, o �,.7 •� tsi., w �(/ ''',to :° .0, , l'i ' .' . ; ,'' p iNi
y I.+�. � so r� 0 ,ia
• 1 75J7 % N
•''',NC,:'.%:-, *6 ".S 4" 401,y7;'4 .'''.T. ".• ,4*, .3"
Kft, th. •t:. .4, ., 2., . . .
,. . v x....4# , 0 7,,* ......“11......_ 34-'373 111W -.....'" :':.l"
,,,,.
`I if "1 U,
4 4 ' y
NCB,. �2H C ._ W� _-
-.1 s YT rf r n v ,
yf,45 _ j' 5
Owner:
Phalanx Fitness, LLC
359 Sunridge Drive
Cameron, NC 28326
The certification shown below applies only to the items listed on this 'Table of Contents'

Phalanx Crossfit 2
Table of Contents
Drainage Area Map 1 Page
Driveway Culvert Drainage Area Map 1 Page
Runoff Coefficient 1 Page
Kirpich Equation 1 Page
NOAA Rainfall Intensity 1 Page
Mannings n 3 Pages
Permanent Clean Water Diversion Swales 2 Pages
Rip Rap Outlet Aprons 6 Pages
Storm Pipe Capacity 1 Page
NOAA Rainfall Depth 1 Page
Pond Stage-Storage Function 2 Pages
TR55 Curve Numbers 1 Page
Kp Values for Pond Barrel 1 Page
Temporary Volume Drawdown 1 Page
Riser Anti-floatation Calculations 1 Page
Simple Method Volume (1 yr, 24 hr) 1 Page
Pond Routing (10, 25, 50, & 100 yr Storm) 12 Pages
Drop Inlet Capacity 1 Page
Sediment Trap 2 Pages
Rip Rap Outlet Apron 06 2 Pages
Temporary Diversion Swale 01C 1 Page �;� (:. >.J.•.��'',;
HDS-5 Driveway Culvert Inlet Control Analysis 1 Page ;�� , �•:
�C••.......• ->
HILLIARD
ENGINL G
Author:Jarrod E. Hilliard, PE, CFM
PO Box 249 Sanford, NC 27331
[phone]
NC License No. P-0836 Date: 12/7/22
Rev. 1/11/23
Rev. 2/14/23
Rev.5/19/23

077d `ON/N33N/JN3 VNI1CAIVO HINON'N0 IBV V0 '
9£80-d.g asue nON t`Jb'.�77/f1 13d SS0210 XNY1VHd m ; l- W o_
worEuuaakeguaP,emel@Pme!11!4f:pew-a . i i °w w rI t
VEBZ-ZSE l6161:amid u 3 'o tq Q
LEELZ ON'P�o;ueS'64Z M3 Od u
',O ue 'a an uuvue ul dt1W t132i t13Jb'N lt/ad o
a$
3 hI
� e� x
,�
3 10
ifil
I I __—_1.....`,\ ` 1 -
I, 1 \ '1 `\ 1 \ i �` 14. 1IIIII P3I'r ' '
_ iz ti \ \ 1n t \ 1 I I\�tV i 1
�� , �_ � � � � off me 1 � )1 !t \� h
tI\'�J—\` y/ 1` \\ , m � ~ ~ \�.� — ~ a.iW.\�¢�N �1-9� 1141I \ \ J �\
'r \IF n o� w WO Q�0p too \I1 1t/ \ 1
/ £✓i/ � ,\✓ I/,' ' �ti (((111/ i:IIfl
hi
\ 1 � 2 !1 � � , i —
L 0 \ 1 \ °a \�M Z`` o¢ ( \\� I i \c \ w0 m m _ d 1 (I 1. 11, z4 g 0O_° t' \ It l I ril
I( �"rI iie \ - tl -\ \� Z —I ! I\ ('( \
QQov ) � cOor�ou�, _3GM`- 1 \�° Za, _ \ -1I� /
/ i( fI o a"O a� aP_ u \ sue` \\I\\,V �\ a°jooa I h l <,\\ lllti I/
r 1 �N Zrn� �� ` I\ ) 1 \ r \ ( l ( II � _-1 \
1 l lid o 1 \ Z `
fc
_ 1,"1 iy1 —��,5 vv vI vV v�r� 11) i ( ) i ` AV ��\� Al1vl
> ) _i_,; i 1 7-_,'"c ' i s__i 3 _ t•-."jr-I''.4'-----___) —--—\
1J t �� v ti l 1 1 V l ) 1 \
I I ��1 I ! 1 i �' \ r7 � v \1I /i
T ,v.t• !� . 1 t v , r-- 1 gs,,
yo rr� t L Z t 'c, ) a1 1 ®®® , I t I ..el ite\i 1///(N1 — tA\
C \ f P t i !I I-s i,A r 1 ti\* ill 1 TI
Sq 1_I ,- \ �' ) , k .,t I I I 1 11 \
" —5 d d!' � a4 fll�1{ � �\ v� � �V �, i\ 2 I .. ��O ;y -I�I�II,ir��
V I� ' III v I I I I a - I I
a r c )
I'� f J � � A I D , 1 r I'._ F:fi
a 1, ItH
irni r--
I yk t\ 1 �ii. i --
1 ^
cf1 I. b I h _.�-- --� i. .a,_r' i i I+ '.
Hrote: z
1: —1
\s I ^s , — \ h4j
r \< z \t ?r1 .� �� ��� (Ti1t
II�i 1 \
/J I o4, IC+ I` i n�j �1 t \, A, \\\N ,� ��Irllll�lll \ ,I1
• I\Gz ( ti l? ) 1 e �.��•al ! ; _,,\1 L `\ 4,1 j11 1j 10,/r�r-' •-
• I iY \��Iw. , I —_�/ v iiJl Ill�ljjlt�l��
• Ilit( Ill I r
•i----- ` C 1 s o oa ii 1 II II�II'I II 1 I
1 j 1 ¢ \> w v az, m o h� - 1 1II IIII III, I/I \
¢ n O U
1) -�I�,-�ss---o¢�U�¢��o cz C ---- - 1 � I 111`II � ‘\
r
I p ti Z�EzE� i\S> J J,,J g1U'i11a11NIill/
c E 1 ,_ I\�III IIINII f(/
1 I d —L---- o o, ti� z ti j IIII III 141 f,
I — o I�

\ / /
/`----- -N N, N>NN e .
\ •` / /
\ \ i.
\ e
N
i„.....„........„.....N.
N \ v
`N %
1
/ .i,i „
,,,, /I /
---� lir/
\ r
_ 'INLET DRAINAGE AREA: /�� /\
''
DA 12.37 acres / >1"� _I25�= 8.75 in/hr \
`A,, I c = 0.5 (Business: Neighborhood Areas)
Q25: 54.12 cfs
N / DRAINAGE AREA *VAN "WZ,,e
I, • IMPERIVOU9ARE4 ',/I
. :�
.e Impervious cral p��.........0 \ e fsv
j
,/ v 110,go r ` s
A,,,,,,,,,,.....‘,....,
, 010-236 cfs S e
/ i _V , ' RG AREA e ,,1 = 2S2AC '/A".„
/
.� a MPER OU6 p
.. 4:� (
'• m
•
sbp�l
•
`,,, ~ - 1 �f/� /i „ac
ter
-\ -. ,j ;, PHALANX CROSSFIT
WET POND P,Ni, e' /
I re � � �rJ -.'A 729AR ' Uk
DRIVEWAY CULVERT
i ; % ( M 12]%slop) moo
41 ,
l ,0.91mpe fir
�j k
I1' ` OB in
'
O,0 486 Os
4
DRAINAGE AREA MAP

8
Table 8.03b Land Use C Land Use C
Value of Runoff Coefficient
(C) for Rational Formula Business: Lawns:
Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10
Neighborhood areas 0.50-0.70 Sandy soil, ave., 0.10-0.15
2-7%
Residential: Sandy soil, steep, 0.15-0.20
Single-family areas 0.30-0.50 7%
Multi units, detached 0.40-0.60 Heavy soil, flat, 2% 0.13-0.17
Multi units,Attached 0.60-0.75 Heavy soil, ave., 0.18-0.22
Suburban 0.25-0.40 2_7%
Heavy soil, steep,
Industrial: 7% 0.25-0.35
Light areas 0.50-0.80
Heavy areas 0.60-0.90 Agricultural land:
Parks, cemeteries 0.10-0.25 Bare packed soil
Smooth 0.30-0.60
Playgrounds 0.20-0.35 Rough 0.20-0.50
Cultivated rows
Railroad yard areas 0.20-0.40 Heavy soil no crop 0.30-0.60
Heavy soil with
Unimproved areas 0.10-0.30 crop 0.20-0.50
Streets: Sandy soil no crop 0.20-0.40
Asphalt 0.70-0.95 Sandy soil with
Concrete 0.80-0.95 crop 0.10-0.25
Brick 0.70-0.85 Pasture
Heavy soil 0.15-0.45
Drives and walks 0.75-0.85 Sandy soil 0.05-0.25
Woodlands 0.05-0.25
Roofs 0.75-0.85
NOTE: The designer must use judgement to select the appropriate C
value within the range for the appropriate land use. Generally, larger
areas with permeable soils, flat slopes, and dense vegetation should
have lowest C values. Smaller areas with slowly permeable soils, steep
slopes, and sparse vegetation should be assigned highest C values.
Source: American Society of Civil Engineers
8.03.6 Rev.6/06

PHALANX CROSSFIT
KIRPICH EQUATION
FOR TIME OF CONCENTRATION COMPUTATIONS
Tc- [K/128] [L3/H1°385
K: 1
L: 568
H: 26
Tc: 3.38 Minutes
Use: 5.00 minutes

Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.2747...
NOAA Atlas 14,Volume 2,Version 3
il Location name: Cameron, North Carolina,USA*
Latitude: 35.2747°, Longitude: -79.0661°
Elevation:391.72 ft**
-.r.&" *source:ESRI Maps F
**source:USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF_tabular I PF_graphical I Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average recurrence interval(years)
Duration
1 2 5 10 25 50 100 200 500 1000
5-min 5.21 6.16 7.15 7.90 8.75 9.35 9.91 10.4 11.0 11.5
(4.72-5.81) (5.57-6.85) (6.48-7.97) (7.13-8.77) (7.86-9.71) (8.39-10.4) (8.84-11.0) (9.25-11.5) (9.70-12.2) (10.0-12.7)
10-min 4.16 4.92 5.73 6.31 6.97 I 7.45 7.88 8.26 I 8.71 9.03
(3.77-4.64) (4.46-5.48) (5.18-6.38) (5.70-7.01) (6.26-7.74) (6.68-8.25) (7.03-8.72) (7.33-9.14) I (7.67-9.64) (7.90-9.99)
15-min 3.47 4.12 4.83 5.32 5.89 6.28 6.64 6.94 7.31 7.56
(3.14-3.86) (3.74-4.59) (4.37-5.38) (4.81-5.92) (5.30-6.54) (5.64-6.96) (5.92-7.35) (6.17-7.69) (6.43-8.09) (6.61-8.36)
30-min 2.38 2.85 3.43 3.86 4.36 4.73 5.08 5.41 5.82 6.12
(2.15-2.65) (2.58-3.17) (3.11-3.82) (3.48-4.29) (3.92-4.84) (4.25-5.25) (4.53-5.63) (4.80-5.98) (5.12-6.43) (5.35-6.77)
60-min 1.48 1.79 2.20 2.51 2.91 3.21 3.50 3.79 4.17 4.47
1 (1.34-1.65) (1.62-1.99) (1.99-2.45) (2.27-2.79) (2.61-3.22) I (2.88-3.55) (3.12-3.88) (3.37-4.20) (3.67-4.62) (3.91-4.94) 1
2-hr 0.870 1.05 1.32 1.52 1.78 1.98 2.19 2.40 2.67 2.88
(0.780-0.978) (0.947-1.18) (1.18-1.48) (1.36-1.70) (1.58-1.99) (1.76-2.22) (1.93-2.45) (2.10-2.68) (2.32-2.98) (2.48-3.22)
3-hr 0.616 0.745 0.935 1.09 1.29 1.45 1.62 1.79 2.03 2.23
(0.554-0.693) (0.671-0.839) (0.841-1.05) (0.973-1.22) (1.15-1.44) (1.29-1.63) (1.42-1.81) (1.56-2.00) (1.75-2.27) (1.90-2.49)
6-hr 0.368 0.446 0.560 0.651 0.776 I 0.877 0.982 1.09 1.24 1.37
(0.335-0.409)j(0.406-0.494) (0.508-0.620) (0.589-0.720)1(0.697-0.856),(0.782-0.967) (0.868-1.08) (0.956-1.20) (1.08-1.37) 1 (1.17-1.50)
12-hr 0.216 0.262 0.331 0.386 1 0.464 0.527 0.594 0.665 0.766 1 0.847
(0.196-0.240) (0.238-0.290) (0.300-0.366) (0.348-0.427) (0.415-0.511) (0.469-0.580) (0.523-0.652) (0.579-0.729) (0.657-0.839) (0.717-0.928)
24-hr 0.128 0.155 0.195 0.227 0.271 0.306 0.342 0.379 0.431 0.472
(0.119-0.138) (0.143-0.167) (0.181-0.211) (0.210-0.245) (0.249-0.292) (0.281-0.330) (0.313-0.369) (0.347-0.409) (0.392-0.465) (0.427-0.509)
2-day 0.074 0.090 0.112 I 0.130 0.155 I 0.174 0.194 0.215 0.244 0.266
(0.069-0.080) (0.083-0.096) (0.104-0.121) (0.121-0.140) (0.143-0.166) (0.160-0.187) (0.178-0.209) (0.197-0.232) (0.222-0.263) (0.241-0.287)
3-day 0.053 0.063 0.079 0.091 0.108 0.122 0.135 0.150 0.169 0.185
(0.049-0.056) (0.059-0.068) (0.073-0.085) (0.085-0.098) (0.100-0.116)1(0.112-0.130) (0.125-0.145) (0.137-0.160) (0.155-0.182) (0.168-0.199)
4-day 0.042 0.050 0.062 0.072 0.085 0.095 0.106 0.117 0.132 0.144
(0.039-0.045)1(0.047-0.054) (0.058-0.066) (0.067-0.076) (0.079-0.090) (0.088-0.101) (0.098-0.113) (0.107-0.125) (0.121-0.141) (0.131-0.154)
7-day 0.028 0.033 0.040 0.046 0.054 0.061 0.067 0.074 0.083 0.091
(0.026-0.030) (0.031-0.035) (0.038-0.043) (0.043-0.049) (0.050-0.058) (0.056-0.065) (0.062-0.072) (0.068-0.079) (0.076-0.089) (0.083-0.097)
10-day 0.022 0.026 0.032 0.036 0.042 0.046 0.051 0.055 0.062 0.066
(0.021-0.023) (0.025-0.028) (0.030-0.034) (0.034-0.038) (0.039-0.044) (0.043-0.049) (0.047-0.054) (0.051-0.059) (0.057-0.066) (0.061-0.071)
20-day 0.015 0.018 0.021 0.023 0.027 0.029 0.032 0.035 0.039 0.042
(0.014-0.016) (0.016-0.019) (0.019-0.022) (0.022-0.025) (0.025-0.029) (0.027-0.031) (0.030-0.034) (0.032-0.037) (0.036-0.041) (0.038-0.045)
30-day 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031
(0.012-0.013) (0.014-0.015) (0.016-0.018) (0.018-0.020) (0.020-0.023) (0.022-0.025) (0.023-0.027) (0.025-0.029) (0.027-0.031) (0.029-0.033)
45-day 0.010 0.012 0.014 0.015 0.017 I 0.018 0.020 0.021 0.023 0.024
(0.010-0.011) (0.012-0.013)i(0.013-0.015) (0.014-0.016) (0.016-0.018)1(0.017-0.020) (0.019-0.021) (0.020-0.022)I(0.021-0.024) (0.022-0.026)
60-day 0.009 0.011 0.012 0.014 0.015 0.016 0.017 0.018 0.020 0.021
(0.009-0.010) (0.010-0.012) (0.012-0.013) (0.013-0.014) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.018-0.021) (0.019-0.022)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates
(for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds
are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
1 of 4 10/4/2022,8:51 AM

ESTIMATING ROUGHNESS COEFFICIENTS
This section describes a method for estimating the roughness coefficient n for
use in hydraulic computations associated with natural streams_floodways. and
excavated channels. The procedure applies to the estimation of n in Manni ng's
formula (_Appendix S.05).
Designed By: JEH Date: 11/29/22
Checked By: JEH Date: 11/29/22
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.:
Site Location (City/Town) Harnett Co.
Site Id. n/a
Step 1. Selection of bask value of n. Select a basic n value for a straight.
uniform. smooth channel in the natural materials involved. The conditions of
straight alignment.uniform cross section,and smooth side and bottom surfaces
without vegetation should be kept in mind. Thus. basic n varies only with the
material than forms the sides and bottom of the channel. Select the basic n for
natural or excavated channels from Table S.04a. If the bottom and sides of a
channel consist of different materials. select an intermediate value.
Channels in earth
Basic n value (n=0.020) 0.02 Table 8.04a
Step 2. Selection of modifying value for surface irregularity. This factor
is based on the degree of roughness or irregularity of the surfaces of channel
sides and bottom. Consider the actual surface irregularity first in relation
to the degree of surface smoothness obtainable with the natural materials
involved. and second in relation to the depths of flow expected. If the surface
irregularity is comparable to the best surface possible for the channel materials.
assign a modifying value of zero. Irregularity induces turbulence that calls for
increased modifying values_ Table 8.04b may be used as a guide to selection
of these modifying values
Modifying value: channel
surface irregularity Smooth (0.000) 0 Table 8.04b
Step 3. Selection of modifying value for variations in the shape and size of
cross sections. In considering this factor.judge the approximate magnitude of
increase and decrease in successive cross sections as compared to the average.
Gradual and uniform changes do not cause significant turbulence. Turbulence
increases with the frequency and abruptness of alternation from large to small
channel sections_

Shape changes causing the greatest turbulence are those for which flow shifts
from side to side in the channel. Select modifying values based on Table
8.04c.
Modifying value: channel
cross section Gradual (0.000) 0 Table 8.04c
Step 4. Selection of modifying value for obstructions. This factor is based
on the presence and characteristics of obstructions such as debris deposits.
stumps. exposed roots. boulders. and fallen and lodged logs. Take care that
conditions considered in other steps not be double-counted in this step.
In judging the relative effect of obstructions. consider the degree to which
the obstructions reduce the average cross-sectional area at various depths and
the characteristics of the obstructions. Sharp-edged or angular objects induce
more turbulence than curved. smooth-surfaced objects. Also consider the
transverse and longitudinal position and spacing of obstructions in the reach.
Select modifying values based on Table 8.04d.
Modifying value: effect of
obstructions Negligible (0.000) 0 Table 8.04d
Step 5. Selection of modifying value for vegetation. The retarding effect
of vegetation is due primarily to turbulence induced as the water flows around
and between limbs. stems. and foliage and secondarily to reduction in cross
section. As depth and velocity increase_ the force of flowing water tends to
bend the vegetation. Therefore.the ability of vegetation to cause turbulence is
related to its resistance to bending. Note that the amount and characteristics of
foliage vary seasonally. In judging the retarding effect of vegetation. consider
the following: height of vegetation in relation to depth of flow. its resistance to
bending. the degree to which the cross section is occupied or blocked. and the
transverse and longitudinal distribution of densities and heights of vegetation
in the reach. Use Table 8.04e as a guide.
Modifying value: vegetation High (0.025-0.050) 0.0375 Table 8.04e
Step 6. Computation of irs for the reach. The first estimate of roughness
for the reach. ri. is obtained by neglecting meandering and adding the basic rr
value obtained in step 1 and modifying values from steps 2 through S.
ns = n + ! modifying values
Straight channel subtotal, ns 0.0575
Step 7. Meander. The modifying value for meandering is not independent of
the other modifying values. It is estimated from the rr• obtained in step 6. and
the ratio of the meandering length to the straight length. The modifying value
for meandering may be selected from Table 8.04f.

Length of meandering
channel (ft) 53
Length of straight line (ft) 438
Meander ratio (ft/ft) 0.121004566
Modifying value:
meandering of channel Minor(0.00) 0 Table 8.04f
Meandering modification o.000
Step 8. Computation of n for a channel reach with meandering. Add the
modifying value obtained in step 7. to 77.. obtained in step 6.
Final roughness coefficient,
n 0.058

Permanent Diversion Swale Ola
PHALANX CROSSFIT
OBJECTIVE: Verify Capacity of Diversion Ditch Based Upon Q10 storm event.
Check that swale will non-erosively pass the Q10 storm event
SOLUTIONS: Mannings Flow Equation
RUNOFF CONDITIONS c: A(ac): 110(cfs):
0.3 0.55 7.90
m
Q10= 1.30 cfs
MAXIMUM d= 0.4500 ft (min.flow depth for Q10 storm) A= 1.41 FTA2
Slope Condition P= 4.43 FT
n= 0.058 (computed) R= 0.32
B= 2 ft(min.width) Q10 Storm= 1.30 CFS
Z Left= 2 :1(Side Slope) V10 Storm= 0.93 FPS
Z Right= 3 :1(Side Slope)
Avg.S= 0.006000 ft/ft(avg.slope) W= 4.25 FT
SHEAR STRESS: T= Shear Stress Y= 62.4 PCF
T= 0.168 PSF d= 0.45 FT
S= 0.01 FT/FT
RECOMMENDED LINING: Seed and Mulch With Contractor's Blend and Install Excelsior Matting or Equivalent
SAY:6"DEPTH,4.25'NATURAL FLOW SPREAD AT TERMINUS
TERMINOLOGY:
Q= Peak Discharge,(CFS) A= Cross-Sectional Area of Flow,(FT^2)
V= Permissible Velocity,(FPS) P= Wetted Perimeter of the Flow,(FT)
d= Maximum Depth of Water,(FT) R= Hydraulic Radius,(FT)
Vt=Trial Velocity,(FPS) S= Slope of the Channel,(FT/FT)
n= Manning's"n"Coefficient Q= Discharge,(CFS)
V*R= Product of Velocity and Hydraulic Radius V= Velocity,(FPS)
B= Bottom Width of Channel,(FT) W= Top Width of Water in Channel,(FT)
Z= Side Slope of Channel (Z:1) Y= Specific Weight of Water(62.4 PCF)
CHANNEL LINING:
With velocities less than 217s use Seed and Mulching
With velocites greater than 2 f/s use Temporary Ditch Liner
:if T<1 then use Coir Wattle against silt fence
:if T>1 then use other lining

Permanent Diversion Swale Olb
PHALANX CROSSFIT
OBJECTIVE: Verify Capacity of Diversion Ditch Based Upon Q10 storm event.
Check that swale will non-erosively pass the Q10 storm event
SOLUTIONS: Mannings Flow Equation
RUNOFF CONDITIONS c: A(ac): 110(cfs):
0.3 1.57 7.90
Q10= 3.72 cfs
MAXIMUM d= 0.3500 ft (min.flow depth for Q10 storm) A= 1.71 FTA2
Slope Condition P= 5.89 FT
n= 0.058 (computed) R= 0.29
B= 4 ft(min.width) Q10 Storm= 3.84 CFS
Z Left= 3 :1(Side Slope) V10 Storm= 2.25 FPS
Z Right= 2 :1(Side Slope)
Avg.S= 0.040000 ft/ft(avg.slope) W= 5.75 FT
SHEAR STRESS: T= Shear Stress Y= 62.4 PCF
T= 0.874 PSF d= 0.35 FT
S= 0.04 FT/FT
RECOMMENDED LINING: Enka,North American Green P500,or Sod
SAY:6"DEPTH,6'NATURAL FLOW SPREAD AT TERMINUS
TERMINOLOGY:
Q= Peak Discharge,(CFS) A= Cross-Sectional Area of Flow,(FT^2)
V= Permissible Velocity,(FPS) P= Wetted Perimeter of the Flow,(FT)
d= Maximum Depth of Water,(FT) R= Hydraulic Radius,(FT)
Vt=Trial Velocity,(FPS) S= Slope of the Channel,(FT/FT)
n= Manning's"n"Coefficient Q= Discharge,(CFS)
V*R= Product of Velocity and Hydraulic Radius V= Velocity,(FPS)
B= Bottom Width of Channel,(FT) W= Top Width of Water in Channel,(FT)
Z= Side Slope of Channel (Z:1) Y= Specific Weight of Water(62.4 PCF)
CHANNEL LINING:
With velocities less than 2 f/s use Seed and Mulching
With velocites greater than 2 f/s use Temporary Ditch Liner
:if T<1 then use Coir Wattle against silt fence
:if T>1 then use other lining

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 11/29/2022
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. Inlet of 36" DW Culvert
Total Drainage Area (acres) 12.37
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailw-ater condition unless rehable flood stage elevations
show otherwise.
Pipe diam., Do (in.) 36
Tailwater depth (in.) 12
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 54.12
Velocity (ft./s) 7.67
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d:. size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.6
Minimum apron length, La (ft.) 20
Apron width at pipe outlet (ft.) 9 9
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 23 3
Step 4. Determine the maximuun stone diameter_
d�,, = 1 .5 x d5o
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.9 0
Step 5. Deternune the apron thickness:
Apron thickness = 1.5 x d
1'1?t
Minimum TW Maximum TW
Apron Thickness(ft.) 1.35 0
Step 6. Fit the riprap apron to the site by making it level for the minimuun
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured_ Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfills exist at
pipe outlets or flows are excessive_ a plunge pool should be considered, see
page 8.06_S.

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 11/30/2022
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 36" DW Culvert
Total Drainage Area (acres) 12.37
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified muumtuu tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide fiat areas with no defined channel are assumed
to have a mourn unn tailwater condition unless reliable flood stage elevations
,how otherwise.
Pipe diam., Do (in.) 36
Tailwater depth (in.) 12
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 54.12
Velocity (ft./s) 7.67
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d5,,riprap size and minimum apron length
(La). The d,c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.6
Minimum apron length, La (ft.) 20
Apron width at pipe outlet (ft.) 9 9
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 23 3
Step 4. Determine the maximum stone diameter:
dmax = '1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.9 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d,.,3,
Minimum TW Maximum TW
Apron Thickness(ft.) 1.35 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and alone channel banks until stability is assured. Keep the
apron as straight as possible and alien it with the flow of the receiving stream
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfalls exist at
pipe outlets or flows are excessive. a plunge pool should be considered. see
page 8.06.8.

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 5/19/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 02 -SCM Outlet
Total Drainage Area (acres) 0.76
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter_ it is classified minimum tailwater condition.
If it is greater than half the pipe diameter_ it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable Hood stage elevations
show otherwise.
Pipe diam., Do (in.) 3
Tailwater depth (in.) 0
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 0.56
Velocity (ft./s) 16.5
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron_
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.2
Minimum apron length, La (ft.) 7
Apron width at pipe outlet (ft.) 0.75 0.75
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 7.25 0.25
Step 4. Determine the maximum stone diameter:
dmax = 1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.3 0
Step 5. Deternune the apron thickness:
Apron thickness = 1.5 x dr,,
Minimum TW Maximum TW
Apron Thickness(ft.) 0.45 0
Step 6. Fit the riprap apron to the site by making it level for the minimunn
length, La. from Figure 8.06a or Figure 8.06b_ Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfills exist at
pipe outlets or flows are excessive. a plunge pool should be considered, see
page 8.06.8_

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 1/11/2023
Checked By: JEH 1/11/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 03 -Swale 01B Outlet
Total Drainage Area (acres) 1 .57
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified muumtuu tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide fiat areas with no defined channel are assumed
to have a mourn unn tailwater condition unless reliable flood stage elevations
,how otherwise.
Equiv. Outlet diam., Do (in.) 18
Tailwater depth (in.) 0.25
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 3.72
Velocity (ft./s) 2.23
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d5,,riprap size and minimum apron length
(L). The d,c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.35
Minimum apron length, La (ft.) 9
Apron width at pipe outlet (ft.) 4.5 4.5
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 10.5 1.5
Step 4. Determine the maximum stone diameter:
dmax = '1.5xd50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.525 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d,.,3,
Minimum TW Maximum TW
Apron Thickness(ft.) 0.7875 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfalls exist at
pipe outlets or flows are excessive. a plunge pool should be considered. see
page 8.06.8.

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 11/29/2022
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs NOT WITHIN
Id. 04 -Swale 01A Outlet RANGE OF
Total Drainage Area (acres) 0.55 CHART
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailw-ater condition unless rehable flood stage elevations
show otherwise.
Equiv. Outlet diam., Do (in.) 18
Tailwater depth (in.) 0.25
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 1 .3
Velocity (ft./s) 0.93
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d:. size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.35
Minimum apron length, La (ft.) 9
Apron width at pipe outlet (ft.) 4.5 4.5
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 10.5 1.5
Step 4. Determine the maximuuu stone diameter_
d�,, = 1 .5 x d5o
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.525 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d
1'1?I
Minimum TW Maximum TW
Apron Thickness(ft.) 0.7875 0
Step 6. Fit the riprap apron to the site by mc'akmg it level for the nunnnunl
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured_ Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Sonic locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfills exist at
pipe outlets or flows are excessive_ a plunge pool should be considered, see
page 8.06_S.

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 11/29/2022
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. 05 -15" HDPE Outlet
Total Drainage Area (acres) 0.76
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide fiat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
,how otherwise.
Outlet diam., Do (in.) 15
Tailwater depth (in.) 0.5
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 5.4
Velocity (ft./s) 4.4
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d5o riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.2
Minimum apron length, La (ft.) 9
Apron width at pipe outlet (ft.) 3.75 3.75
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 10.25 1.25
Step 4. Determine the maximum stone diameter.
dux = 1.5xd50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.3 0
Step 5. Determine the apron thickness:
Apron thickness = I.5 x d,„%
Minimum TW Maximum TW
Apron Thickness(ft.) 0.45 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfills exist at
pipe outlets or flows are excessive• a plunge pool should be considered. see
page 8.06.8.

E E
O 0
+) +,
aJ L L
5.
Z N N
0 to
N UJ
Q M1, } }
(D Y
U
n N
•
U ii M
• Lr1
U ^ LD
N 0
Q c
Ln N
c 00 W
LJ7 �
U
O O
}
J 1-
O a Ldn •
•
Q
U
LL
O
re L.)W W -I
m a
2 a
Z
GJ
OA
LyE w T-1
LL UVI Ln
N 0
0
N
114
X t G. M
Q H N 'NJ-
3
U,
U N Q Q
O 0-
LSD '71-
.�.
N
O 0
N cu O O
to Q 0 l0 O
d N l0
O 0
ci •
0 aJ Ln
W U M
Q. C
cc
LJJ (9
J Z
—• u d
U
a < H
> z
= o
0

Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.2747...
NOAA Atlas 14,Volume 2,Version 3
te Location name: Cameron, North Carolina,USA*
Latitude: 35.2747°, Longitude: -79.0661°
Elevation:391.72 ft**
4•4447Eeof• *source:ESRI Maps F
**source:USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF_tabular I PF_graphical I Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90%confidence intervals (in inches)1
Average recurrence interval(years)
Duration
1 2 5 10 25 50 100 200 500 1000
5-min 0.434 I 0.513 I 0.596 1 0.658 0.729 0.779 0.826 0.868 0.918 I 0.956
(0.393-0.484) (0.464-0.571) (0.540-0.664) (0.594-0.731) (0.655-0.809) (0.699-0.864) (0.737-0.915) (0.771-0.961) (0.808-1.02) (0.836-1.06)
10-min 0.694 0.820 0.955 1.05 1.16 1.24 1.31 1.38 1.45 1.51
(0.628-0.773) (0.743-0.913) (0.864-1.06)1 (0.950-1.17) (1.04-1.29) (1.11-1.38) (1.17-1.45) (1.22-1.52) (1.28-1.61) (1.32-1.67)
15-min 0.867 1.03 1.21 1.33 1.47 1.57 1.66 1.74 1.83 1.89
(0.784-0.966) (0.934-1.15) (1.09-1.35) (1.20-1.48) (1.32-1.64) (1.41-1.74) (1.48-1.84) (1.54-1.92) (1.61-2.02) (1.65-2.09)
30-min 1.19 1.42 1.72 1.93 2.18 2.37 2.54 2.70 2.91 3.06
(1.08-1.33) (1.29-1.59) (1.55-1.91) (1.74-2.14) (1.96-2.42) (2.12-2.62) (2.27-2.81) (2.40-2.99) (2.56-3.22) (2.68-3.39)
60-min 1.48 1.79 2.20 2.51 2.91 3.21 3.50 3.79 4.17 4.47
(1.34-1.65) (1.62-1.99) 1 (1.99-2.45) (2.27-2.79) I (2.61-3.22) (2.88-3.55) (3.12-3.88) (3.37-4.20) (3.67-4.62) (3.91-4.94)
2-hr 1.74 2.11 2.63 3.03 3.56 3.97 4.38 4.79 5.34 5.77
(1.56-1.96) (1.89-2.37) (2.36-2.96) (2.71-3.40) (3.17-3.99) (3.52-4.45) (3.86-4.90) (4.20-5.36) (4.63-5.97) (4.96-6.45)
3-hr 1.85 2.24 2.81 3.26 3.87 4.36 4.86 5.39 6.11 6.68
(1.66-2.08) (2.02-2.52) (2.53-3.16) (2.92-3.66) (3.45-4.33) (3.86-4.88) (4.27-5.44) (4.69-6.02) (5.26-6.82) (5.70-7.47)
6-hr 2.21 2.67 3.35 3.90 4.64 5.25 5.88 6.53 7.45 8.18
(2.00-2.45) I (2.43-2.96) 1 (3.04-3.71) (3.53-4.31) (4.17-5.13) 1 (4.68-5.79) (5.20-6.47)J (5.72-7.18) (6.44-8.18)I (7.00-8.99)
12-hr 2.61 3.15 3.98 4.65 5.59 6.35 7.16 8.01 9.22 10.2
(2.37-2.89) (2.87-3.49) (3.61-4.41) (4.20-5.14) (5.00-6.16) (5.65-6.98) (6.30-7.86) (6.98-8.78) (7.91-10.1) (8.64-11.2)
24-hr 3.07 3.71 4.68 5.45 6.50 7.34 8.21 9.11 10.3 11.3
(2.85-3.31) (3.44-4.01) (4.34-5.06) (5.03-5.88) (5.99-7.02) (6.74-7.92) (7.52-8.85) (8.32-9.81) (9.40-11.2) (10.3-12.2)
2-day 3.57 4.30 5.39 6.25 7.43 8.37 9.33 10.3 11.7 12.8
(3.32-3.84) (4.00-4.63) (5.01-5.80) (5.79-6.72) (6.86-7.99) (7.70-8.99) (8.56-10.0) (9.44-11.1) (10.6-12.6) (11.6-13.8)
3-day 3.79 4.56 5.68 6.56 7.78 8.75 9.75 10.8 12.2 13.3
(3.53-4.06) (4.25-4.89) (5.29-6.09) (6.10-7.03) (7.20-8.33) (8.07-9.37) (8.97-10.4) (9.88-11.6) I (11.1-13.1) (12.1-14.3)
4-day 4.01 4.82 5.97 6.88 8.13 9.14 10.2 11.2 12.7 13.8
(3.74-4.28) (4.50-5.15) (5.57-6.37) (6.41-7.33) (7.55-8.68) (8.45-9.74) (9.37-10.8) (10.3-12.0) (11.6-13.6) (12.6-14.8)
7-day 4.63 5.53 6.77 7.75 9.11 10.2 11.3 12.4 14.0 15.2
(4.32-4.96) (5.16-5.93) (6.30-7.26) (7.21-8.31) (8.44-9.75) 1 (9.42-10.9) (10.4-12.1) (11.4-13.3) (12.8-15.0) (13.9-16.4)
10-day 5.28 6.30 7.59 8.61 9.98 11.1 12.1 13.3 14.8 15.9
(4.96-5.62) (5.91-6.70) (7.12-8.07) (8.06-9.15) (9.31-10.6) (10.3-11.8) (11.3-12.9) (12.3-14.1) (13.6-15.7) (14.6-17.0)
20-day 7.11 8.41 9.97 11.2 12.9 14.1 15.5 16.8 18.6 20.0
(6.68-7.58) (7.90-8.97) (9.35-10.6) (10.5-11.9) (12.0-13.7) (13.2-15.1) (14.4-16.5) (15.5-17.9) (17.1-19.8) (18.4-21.4)
30-day 8.85 10.4 12.2 13.5 15.3 16.6 18.0 19.3 21.1 22.5
(8.34-9.41) (9.82-11.1) (11.4-12.9) (12.7-14.4) (14.3-16.2) (15.6-17.7) (16.8-19.2) J (18.0-20.6) (19.6-22.6) (20.8-24.1)
45-day 11.2 13.2 15.1 16.6 18.5 20.0 21.4 22.8 24.6 26.0
L (10.6-11.9) (12.4-13.9) (14.2-16.0) (15.6-17.6) (17.4-19.6) (18.8-21.2) (20.1-22.7) (21.3-24.2) (23.0-26.2) (24.2-27.7)
60-day 13.4 15.7 17.9 19.5 21.6 23.2 24.7 26.2 28.1 29.6
(12.7-14.2) (14.9-16.6) (16.9-18.8) (18.4-20.5) (20.4-22.8) (21.9-24.4) (23.3-26.1) (24.6-27.7) (26.4-29.8) (27.7-31.4)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates
(for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds
are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
1 of 4 10/4/2022,8:50 AM

w
CD J
< 0
= O
O D_
v" z
W W
m
as
J_ g
Q =
> W
Q D_
J IL
• 0
U CO
<
Q
I
CD
+-,
Its O O( 0
Ln O O c-1
U,
uJ
w
co co
N 0
C 0 Cr) c-I
— C IN lb
C
O_
Y
In
N 0 CD ra
O a) C
O - C O O
V Iz
++
Z C
a)
M c
LL E 01U 0 O 0
C O r l l--
W v +
O °)
m
�
a o a
cc z tto
O
'�_^ dA MS
0 0 In u In ,n
IA a) •'- N 00 Li.) UI UI
a1 t� • E u O' r-I on' cri
W coo ++ u
0 Ua
Q t4 Q-
U - II II
Q 0 O UI O
p 0 co/ m
Z a > o ri ri
O o u
a 0 s
I-
++
W ~
L 0
Li) o a)
In N .-I0 fa 0
CC fa in a lD Cr LIDlD r-I O
U N 2 ai O < op O I� m 0
X l\D N 'a 'a f0 I� In N l-I i�-I 0
O Y a) c L v N m a0 r4 O
Q rsJ rl N as O L Q rI
Q L 7,RS +�+
D- u > O >�
W J >
L
U
+al ++ CO0 W c-I c-I Q
I I
O p Vf 3 m m m u w
. ++ O
d = 0 U Z c C II
3
W O Qa
> m > (
W 0 0 a) CC

Un
1
N
O a
N * Li-)
N N
t:
I I M
to
II
to
f6 _ Ln
r+
00
Q O a)
d d
z
O LL
a)
cn 00
d ro
p) O O
ate+ - O
fn T a)
O f6
E
L
O
U a)
L Q
a)a) -
C _ LO
0
J O a
O
O
u
LL
C1 a)
I I I I I I • I I I O 00
0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 O
0 0 0 0 0 0 0 0 0 0 0
O 00 CO N O O O N O N
00
to

Chapter 2 Estimating Runoff Technical Release 55
Urban Hydrology for Small Watersheds
Table 2-2a Runoff curve numbers for urban areas 1/
Curve numbers for
----------- Cover description --------------------- ------hydrologic soil group-------
Average percent
Cover type and hydrologic condition impervious area v A B C D
Fully developed urban areas (vegetation established)
Open space(lawns,parks,golf courses,cemeteries,etc.)3i:
Poor condition(grass cover<50%) 68 79 86 89
Fair condition(grass cover 50%to 75%) 49 69 79 84
Good condition(grass cover>75%) 39 61 74 80
Impervious areas:
Paved parking lots,roofs,driveways,etc.
(excluding right-of-way) I= 98 98 98
Streets and roads:
Paved;curbs and storm sewers(excluding
right-of-way) 98 98 98 98
Paved;open ditches(including right-of-way) 83 89 92 93
Gravel(including right-of-way) 76 85 89 91
Dirt(including right-of-way) 72 82 87 89
Western desert urban areas:
Natural desert landscaping(pervious areas only) 4/ 63 77 85 88
Artificial desert landscaping(impervious weed barrier,
desert shrub with 1-to 2-inch sand or gravel mulch
and basin borders) 96 96 96 96
Urban districts:
Commercial and business 85 89 92 94 95
Industrial 72 81 88 91 93
Residential districts by average lot size:
1/8 acre or less(town houses) 65 77 85 90 92
1/4 acre 38 61 75 83 87
1/3 acre 30 57 72 81 86
1/2 acre 25 54 70 80 85
1 acre 20 51 68 79 84
2 acres 12 46 65 77 82
Developing urban areas
Newly graded areas
(pervious areas only,no vegetation)5i 77 86 91 94
Idle lands(CN's are determined using cover types
similar to those in table 2-2c).
1 Average runoff condition,and Ia=0.2S.
2 The average percent impervious area shown was used to develop the composite CN's.Other assumptions are as follows:impervious areas are
directly connected to the drainage system,impervious areas have a CN of 98,and pervious areas are considered equivalent to open space in
good hydrologic condition.CN's for other combinations of conditions may be computed using figure 2-3 or 2-4.
3 CN's shown are equivalent to those of pasture.Composite CN's may be computed for other combinations of open space
cover type.
4 Composite CN's for natural desert landscaping should be computed using figures 2-3 or 2-4 based on the impervious area percentage
(CN=98)and the pervious area CN.The pervious area CN's are assumed equivalent to desert shrub in poor hydrologic condition.
5 Composite CN's to use for the design of temporary measures during grading and construction should be computed using figure 2-3 or 2-4
based on the degree of development(impervious area percentage)and the CN's for the newly graded pervious areas.
(210-VI-TR-55,Second Ed.,June 1986) 2-5

8
2gh o5
3. Pipe Flow: Q = a [1 +K.+KP L
where:
Q=discharge in cubic feet per second(cfs)
a=cross-sectional area of the barrel in square feet
g =acceleration due to gravity,32.2 ft/sec2
h=head above the centerline of the outlet end of the barrel
Km = coefficient of minor losses, can be assumed to be 1.0 for
most principal spillway systems
L =barrel length in feet
K, =pipe friction coefficient:
_ 5087n2 (See Table 8.07c for KP values for
di413 common size of pipe.)
n =Manning's coefficient of roughness,use n=0.025 for
corrugated metal pipe
n =0.015 for reinforced concrete pipe
di =inside diameter of the barrel in inches
Select riser and barrel dimensions so that the riser has a cross-sectional area
at least 1.5 times that of the barrel. Spillway hydraulics are improved by
maximizing weir flow and minimizing orifice flow. See Table 8.07b for
recommended riser/barrel proportions.
Table 8.07a Kp Values for Common Sizes of Pipe
Pipe Diameter Flow Area Manning's Coefficient
(inches) (square feet) 0.015 0.025
6 0.196 0.1050 0.2916
8 0.349 0.0715 0.1987
10 0.545 0.0531 0.1476
12 .0785 0.0417 0.1157
14 1.069 0.0339 0.0942
15 1.23 0.0309 0.0859
16 1.40 0.0284 0.0789
18 1.77 0.0243 0.0674
21 2.41 0.0198 0.0549
24 3.14 0.0165 0.0459
27 3.98 0.0141 0.0393
30 4.91 0.0123 0.0341
36 7.07 0.0096 0.0267
42 9.62 0.0078 0.0218
48 12.57 0.0066 0.0182
54 15.90 0.0056 0.0156
60 19.64 0.0049 0.0135
8.07.6 Rev.5/13

,•i
I
W O d. 0 m m N N ul
up m V m l.fl rsJ 0
O lD lD O O N ci O
cal
e-1
6
a) a) a)
c $ •• E E .. ..
Q a N I d i o
c O
m
O
ti
00 L▪ m m m VD ci
Ln N a m N V1 h c-1
O N lD O LD Ni O
co O ,i
O
O
a) a) a)
•• •• E .. E
Q aT $ v i i '
Z 10 V V " O O c -c c L c 'O
5 •Q N al
I ra a a
o 0 0
0
LO
V W 6 a m VD N NO LID
(.4
to
O N D O ti O
CC J J w O
VD
O V) V O
0 a) a) a)
~ Q _ In l0 . ,r ^ ) .. w E •• E •• N
LI_ N O e.1 a-1 N `c p Cr t 1- i ~ i ~ T
VI E IN IN m m M E V V v O c v c v c to
O M M N f0 to 2 0 •ro al al
cc as 0 a N d o O
CC
U CI -
Z
O o V m D co
Q j C N O a) a 1 Ln V V m 0 4 O o0
Z 'pp 30 �' O N O NO O• O VD
a CIS -a na 5 O N
CC -to
a) C a, o
Q : -c a` x o
a O w C too a) a) a)
a t o m c 4N •• N E .. E .. E
3 > m O o 6 \ ` H v, ~ ^ ~ T
W o c v 47.
v1 E v v v o c v •c t •C ra
I► -a w f0 on 2 O m
0 C co Ct Q N d Q O 8
z 3
cc a
0 -O E
a O
LC
W E ELA W N- d- m ti `~ N N
E O •C m 0 N N
v1 •� 0 0 m lD p O O^ N- m
L 2— O
✓ O
N
T
c-1 a) a) a)
a c .. NN •. N E E E
Y _' 6 $ v I- i I- L I- j,
O c V = O O c c c
Oa 2 N N a
a) a N d o O 8
Y
(6
a)
I-
a.) o0
E m co
oo m
To tri � D m o cri
m D
m
O O ,mi .1 m N
OOV7 N N
O
O ,--1
to O .-i
O \ 6
Q ci
E
a) s
00 .. a) a) a)
a) N .. :" E .. E E ••
Q O u H C H L H y
o X E v 6 v c c c m
w • f0 bA x a E N i -00
a) uo O a N O O O
H Cf

PHALANX CROSSFIT
HARNETT COUNTY, NC
ANTI-FLOATATION COMPUTATIONS LEGEND Enter Data
FOR RECTANGULAR SECTION STRUCTURE Verfiy Data
CONTROL:
Unit Weight of Water: 62.4 lbs/cf
Unit Weight of Conc. 150 lbs/cf
STRUCTURE WEIGHT: o ft
371.50 ft-msl (Rim Elevation)
STRUCTURE SIDES: 1 371.50 ft-msl (Top of Sides)
Riser Inside Length Dimension: 3 ft
Riser Inside Width Dimension: 2.16 ft
Thickness of Concrete: 0.5 ft 0.5 ft
Riser Outside Length Dimensions: 4
Riser Outside Width Dimensions: 3.16 369 ft-msl (Barrel Invert)
Volume of Sides: 15.4 cf 368.5 ft-msl (Initial Bottom of Structure)
Weight of Concrete Sides: 2,310 lbs 369.00 ft-msl (Invert with Anti-Float)
368.50 ft-msl (Bottom with Anti-Float)
0.5 ft
STRUCTURE BOTTOM: STRUCUTRE TOP:
Riser Inside Length Dimension: 3 ft Riser Inside Length Dimension: 3 ft
Riser Inside Width Dimension: 2.16 ft Riser Inside Width Dimension: 2.16 ft
Thickness of Concrete: 0.5 ft Thickness of Concrete: 0 ft
Riser Outside Length Dimensions: 4 ft Riser Outside Length Dimensions: 4 ft
Riser Outside Width Dimensions: 3.16 ft Riser Outside Width Dimensions: 3.16 ft
Volume of Bottom: 6.32 cf Volume of Top Slab: 0 cf
Weight of Concrete Bottom: 0,948 lbs Weight of Concrete Bottom: 0,000 lbs
INITIAL WEIGHT OF STRUCTURE: 3,258 LBS
INITIAL DESIGN O.K.
BOUYANCY FORCE: ANTIFLOTATION:
Weir Elevation: 371.5 ft-msl Use Bottom Inv.Elev: 368.50 ft-msl (Fill with Concrete)
Trial Bottom of Box: 368.5 ft-msl Additional Str.Wt: 0,000 lbs
Inside Area of Riser: 6.48 sq.ft Add.Bouy.Force: 0,000 lbs
Outside Area of Riser: 12.64 sq.ft TOTAL STR.WT: 3,258
Volume of Water Displaced: 37.92 cf TOTAL BOUYANCY: 2,366
Initial Bouyancy Force: 2,366 lbs Safety Factor: 1.3769 (Minimum S.F.must be>=1.1)
Message: Design o.k.

PHALANX CROSS FIT VOLUME COMPUTATIONS
MINIMUM VOLUME REQUIRED. USE SIMPLE METHOD
Regulatory Requirement: Harnett County General Stormwater Management
Additional Requirements: Non-erosive discharge
Design Storm Event Return Interval/Duration: 1 year 24 hour
Post Watershed Size: 0.76 acres
Pre Watershed Size: 0.76 acres
Peak Discharge Rainfall Intensity: 0.128 in/hr
Pre-Development c: 0.1 pasture sandy soils
Post-Development c: 0.81 composite
Estimated Percent Impervious Area: 88.14 % Total Composite CN 91
Impervious Area: 0.670 acres
Pervious Area: 0.090 acres
Design Storm Event Precipitation: 1.00 inch Minimum requirement
Major Hydrologic Soil Group: A WfB
Pervious Land Use CN: 39 lawns(good condition)
Impervious Land Use CN: 98
RUNOFF DETERMINATION:
Simple Method
la: 0.8814 (Impervious fraction)
RD: 1.00 in (Water Quality Storm)
A: 0.76 acres (Watershed Area)
RUNOFF COEFFICIENT(Rv): Formula:R v=0.05+0.9"l a
R,,: 0.84326
VOL.REQUIRED(V): Formula:V=Ro"Rv A
(V): 2,326 ft3 = 17,401 gallons
(V): 0.641 acre-inches

FORMULATING PRE-POST DEVELOPMENT HYDROGRAPHS
Utilize small watershed method&center-weighted storm(Malcom)
Return Period 10 year
I= 7.900 in/hr 10 year,Tc Intensity
Cpre 0.10 (Composite Rational C, See Drainage Area/Computations Map)
Cpost 0.81 (Composite Rational C, See Drainage Area/Computations Map)
A= 0.76 acre
A= 33,106 sf Rainfall 3.9 in (10 year,6 hour storm)
Qpre= 0.60 cfs PRE CN 490 S= 10.41 Q*= 0.27 in
Qpost= 4.86 cfs POST CN 91 S= 0.9 Q*= 2.92 in
Vol -Pre 0,746 cf 0.2*S: 2.0816327
Vol -Post 8,060 cf (If rainfall is less than 20%S, Q*=0)
Tpre 15 min
Tpost 20 min
Time Step 1 min
Time Q-pre Q-post
min cfs cfs
0 0.00 0.00
1 0.01 0.03
2 0.03 0.12
3 0.06 0.27
4 0.10 0.47
5 0.15 0.72
6 0.21 1.01
7 0.27 1.34
8 0.33 1.70
9 0.40 2.07
10 0.45 2.46
11 0.50 2.84
12 0.55 3.21
13 0.58 3.56
14 0.60 3.89
15 0.60 4.18
16 0.59 4.42
17 0.57 4.62
18 0.54 4.76
19 0.50 4.84
20 0.46 4.86
21 0.42 4.82
22 0.38 4.73
23 0.35 4.57
24 0.32 4.36
25 0.29 4.11
26 0.27 3.85
27 0.25 3.61
28 0.23 3.38
29 0.21 3.17
30 0.19 2.97
31 0.17 2.78
32 0.16 2.60
33 0.15 2.44
34 0.13 2.28
35 0.12 2.14
36 0.11 2.00
37 0.10 1.88
38 0.09 1.76
39 0.09 1.65
40 0.08 1.54
41 0.07 1.44
42 0.07 1.35
43 0.06 1.27
44 0.06 1.19
10-YEAR INFLOW
1 of 3

HYDROGRAPH ROUTING THROUGH WET POND
10-YEAR STORM Extrapolated Kp
FORMULAS FROM EC MANUAL 8.07.5 Manning Coefficient
Pipe Diam. Flow Area 0.015 0.025
Type Structure: Riser with Circular Drawdown Outlet and Barrel 2 0.0218 0.4542 1.2617
Orifice Equation:Q.CDA(2gh)°'s 3 0.0491 0.2645 0.7348
Pipe Flow Formula:Cl.a[2gh I 1+Km+KpL]°s 4 0.0872 0.1803 0.5007
Weir Flow Formula:Q=CLH''S 6 0.1963 0.1050 0.2916
Co(Orifice): 0.60 8 0.3489 0.0715 0.1987
Height Change,Weir to 2.00 ft Km 1.0 Standard 0.5451
Orifice Flow 10 0.0531 0.1476
C„„, 3.00 Kp 0.7348 (Table 8.07a) 12 0.7850 0.0417 0.1157
Primary Riser Diam 30.0 in. Length of Barre 20 ft 14 1.0685 0.0339 0.0942
Circum.of Riser 7.85 ft Barrel Diam. 3 in 15 1.2266 0.0309 0.0859
Area of Riser 4.91 ft' Barrel Area: 0.05 ft 2.5 0.0341 0.3373 0.9370
Riser Drawdown Outlet 0.75 in NOTE: Heights measured from normal pool elevation
Orifice Diam.
Number of Orifices 0
Riser Drawdown Outlet 0.00 ft Nornal Pool Height= 0.00 ft
Orifice Area
Existing Soil N/A
Min.Infiltration Rate 0.00 in/hr 1 Height of Riser Weir= 1.00 ft 1
Vol.Lost to Infil. 0 cf/hr
Stage Storage Function:S=3,525 a Z 1.15
Riser Secondary Primary Riser Primary Riser Riser/let Flo wn
Barrel Capacity Total 0utflow
Inflow Volume in Storage Stage Orifice Capacity Capaei y Capaelry Outlet Flow Infill Vol Out Velocity
of of ft Orifice Flow(cis] Weir Flow(cfs) Orifice Flow fct-' ---(cfs; (c/s) (cfa) allif
1 0.03 0,002 0,002 0.0014 #NUM! #NUM. #NUM 0.14 0.00 0.00 0.000 0,000
2 0.12 0,007 0,009 0.0056 #NUM! #NUM. #NUM 0.14 0.00 0.00 0.000 0,000 0.00
3 0.27 0,016 0,025 0.0136 #NUMI #NUM #NUM 0.14 0.00 0.00 0.000 0,000 0.00
4 0.47 0,028 0,053 0.0261 #NUMI #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
5 0.72 0,043 0,097 0.0438 0.00 #NUM #NUM 0.16 0.00 0.00 0.000 0,000 0.00
6 1.01 0,061 0,157 0.0670 0.00 #NUM #NUM 0.17 0.00 0.00 0.000 0,000 0.00
7 1.34 0,081 0,238 0.0960 0.00 #NUM #NUM 0.18 0.00 0.00 0.000 0,000 0.00
8 1.70 0,102 0,340 0.1308 0.00 #NUM #NUM 0.20 0.00 0.00 0.000 0,000 0.00
9 2.07 0,124 0,464 0.1716 0.00 #NUM #NUM 0.21 0.00 0.00 0.000 0,000 0.00
10 2.46 0,147 0,612 0.2181 0.00 #NUM #NUM 0.23 0.00 0.00 0.000 0,000 0.00
11 2.84 0,170 0,782 0.2700 0.00 #NUM #NUM 0.25 0.00 0.00 0.000 0,000 0.00
12 3.21 0,193 0,975 0.3270 0.00 #NUM #NUM 0.26 0.00 0.00 0.000 0,000 0.00
13 3.56 0,214 1,188 0.3885 0.00 #NUM #NUM 0.28 0.00 0.00 0.000 0,000 0.00
14 3.89 0,233 1,422 0.4541 0.00 #NUM #NUM 0.30 0.00 0.00 0.000 0,000 0.00
15 4.18 0,251 1,672 0.5229 0.00 #NUM #NUM 0.32 0.00 0.00 0.000 0,000 0.00
16 4.42 0,265 1,938 0.5943 0.00 #NUM #NUM 0.33 0.00 0.00 0.000 0,000 0.00
17 4.62 0,277 2,215 0.6675 I 0.00 #NUM #NUM 0.35 0.00 0.00 0.000 0,000 0.00
18 4.76 0,285 2,500 0.7418 0.00 #NUM #NUM 0.37 0.00 0.00 0.000 0,000 0.00
19 4.84 0,290 2,791 0.8161 0.00 #NUM #NUM 0.38 0.00 0.00 0.000 0,000 0.00
20 4.86 0,292 3,082 0.8899 0.00 #NUM #NUM 0.40 0.00 0.00 0.000 0,000 0.00
21 4.82 0,289 3,372 0.9621 0.00 #NUM #NUM 0.41 0.00 0.00 0.000 0,000 2.76
22 4.73 0,284 3,655 1.0321 0.00 0.14 4.23 0.42 0.14 0.14 0.000 0,008 8.85
23 4.57 0,274 3,922 1.0972 0.00 0.71 7.37 0.43 0.71 0.43 0.000 0,043 9.04
24 4.36 0,262 4,141 1.1502 0.00 1.37 9.16 0.44 1.37 0.44 0.000 0,082 9.18
25 4.11 0,247 4,305 1.1899 0.00 1.95 10.30 0.45 1.95 0.45 0.000 0,117 9.28
26 3.85 0,231 4,419 1.2173 0.00 2.39 11.02 0.46 2.39 0.46 0.000 0,143 9.34
27 3.61 0,217 4,493 1.2348 0.00 2.68 11.45 0.46 2.68 0.46 0.000 0,161 9.37
28 3.38 0,203 4,535 1.2448 0.00 2.85 11.70 0.46 2.85 0.46 0.000 0,171 9.39
29 3.17 0,190 4,553 1.2493 0.00 2.93 11.80 0.46 2.93 0.46 0.000 0,176 9.39
30 2.97 0,178 4,555 1.2498 0.00 2.94 11.81 0.46 2.94 0.46 0.000 0,176 9.38
31 2.78 0,167 4,545 1.2474 0.00 2.90 11.76 0.46 2.90 0.46 0.000 0,174 9.37
32 2.60 0,156 4,528 1.2432 0.00 2.83 11.66 0.46 2.83 0.46 0.000 0,170 9.35
33 2.44 0,146 4,504 1.2376 0.00 2.73 11.52 0.46 2.73 0.46 0.000 0,164 9.32
34 2.28 0,137 4,478 1.2312 0.00 2.62 11.36 0.46 2.62 0.46 0.000 0,157 9.30
35 2.14 0,128 4,449 1.2243 0.00 2.50 11.19 0.46 2.50 0.46 0.000 0,150 9.28
36 2.00 0,120 4,419 1.2171 0.00 2.38 11.01 0.46 2.38 0.46 0.000 0,143 9.25
37 1.88 0,113 4,388 1.2098 0.00 2.26 10.83 0.45 2.26 0.45 0.000 0,136 9.22
38 1.76 0,105 4,358 1.2025 0.00 2.15 10.64 0.45 2.15 0.45 0.000 0,129 9.20
39 1.65 0,099 4,328 1.1953 0.00 2.03 10.45 0.45 2.03 0.45 0.000 0,122 9.17
40 1.54 0,093 4,298 1.1882 0.00 1.92 10.25 0.45 1.92 0.45 0.000 0,115 9.15
41 1.44 0,087 4,269 1.1813 0.00 1.82 10.06 0.45 1.82 0.45 0.000 0,109 9.13
42 1.35 0,081 4,241 1.1746 0.00 1.72 9.87 0.45 1.72 0.45 0.000 0,103 9.10
43 1.27 0,076 4,214 1.1680 0.00 1.62 9.69 0.45 1.62 0.45 0.000 0,097 9.08
44 1.19 0,071 4,188 1.1617 0.00 1.53 9.51 0.45 1.53 0.45 0.000 0,092 9.06
45 1.11 0,067 4,163 1.1556 0.00 1.45 9.32 0.44 1.45 0.44 0.000 0,087 9.04
46 1.04 0,062 4,139 1.1498 0.00 1.37 9.15 0.44 1.37 0.44 0.000 0,082 9.02
47 0.98 0,059 4,115 1.1441 0.00 1.29 8.97 0.44 1.29 0.44 0.000 0,077 9.00
48 0.91 0,055 4,093 1.1387 0.00 1.22 8.80 0.44 1.22 0.44 0.000 0,073 8.98
49 0.86 0,051 4,071 1.1334 q 0.00 1.15 8.63 0.44 1.15 0.44 0.000 0,069 8.96
50 0.80 0,048 4,050 1.1284 0.00 1.08 8.47 0.44 1.08 0.44 0.000 0,065 8.94
51 0.75 0,045 4,030 1.1235 0.00 1.02 8.31 0.44 1.02 0.44 0.000 0,061 8.93
52 0.70 0,042 4,011 1.1189 0.00 0.97 8.15 0.44 0.97 0.44 0.000 0,058 8.91
53 0.66 0,040 3,993 1.1144 0.00 0.91 7.99 0.44 0.91 0.44 0.000 0,055 8.90
54 0.62 0,037 3,975 1.1101 0.00 0.86 7.84 0.44 0.86 0.44 0.000 0,052 8.88
55 0.58 0,035 3,958 1.1080 0.00 0.81 7.69 0.44 0.81 0.44 0.000 0,049 8.87
56 0.54 0,032 3,942 1.1020 0.00 0.77 7.55 0.44 0.77 0.44 0.000 0,046 8.85
57 0.51 0,030 3,926 1.0982 0.00 0.73 7.41 0.43 0.73 0.43 0.000 0,044 8.84
58 0.47 0,028 3,911 1.0946 0.00 0.69 7.27 0.43 0.69 0.43 0.000 0,041 8.83
59 0.44 0,027 3,897 1.0911 0.00 0.65 7.13 0.43 0.65 0.43 0.000 0,039 8.81
60 0.42 0,025 3,883 1.0877 0.00 0.61 7.00 0.43 0.61 0.43 0.000 0,037 8.80
61 0.39 0,023 3,869 1.0845 0.00 0.58 6.87 0.43 0.58 0.43 0.000 0,035 8.79
62 0.37 0,022 3,857 1.0813 0.00 0.55 6.74 0.43 0.55 0.43 0.000 0,033 8.78
63 0.34 0,021 3,844 1.0784 0.00 0.52 6.62 0.43 0.52 0.43 0.000 0,031 8.77
64 0.32 0,019 3,833 1.0755 0.00 0.49 6.49 0.43 0.49 0.43 0.000 0,029 8.76
65 0.30 0,018 3,821 1.0727 0.00 0.46 6.37 0.43 0.46 0.43 0.000 0,028 8.75
66 0.28 0,017 3,811 1.0701 0.00 0.44 6.26 0.43 0.44 0.43 0.000 0,026 8.43
67 0.26 0,016 3,800 1.0675 0.00 0.41 6.14 0.43 0.41 0.41 0.000 0,025 7.97
68 0.25 0,015 3,790 1.0651 1 0.00 0.39 6.03 0.43 0.39 0.39 0.000 0,023 7.54
69 0.23 0,014 3,781 1.0627 0.00 0.37 5.92 0.43 0.37 0.37 0.000 0,022 7.14
70 0.22 0,013 3,771 1.0605 0.00 0.35 5.81 0.43 0.35 0.35 0.000 0,021 6.76
71 0.20 0,012 3,762 1.0583 0.00 0.33 5.71 0.43 0.33 0.33 0.000 0,020 6.40
72 0.19 0,011 3,754 1.0562 0.00 0.31 5.61 0.43 0.31 0.31 0.000 0,019 6.06
73 0.18 0,011 3,746 1.0542 0.00 0.30 5.50 0.43 0.30 0.30 0.000 0,018 5.74
74 0.17 0,010 3,738 1.0523 0.00 0.28 5.41 0.43 0.28 0.28 0.000 0,017 5.44
75 0.16 0,009 3,730 1.0505 0.00 0.27 5.31 0.43 0.27 0.27 0.000 0,016 5.16
76 0.15 0,009 3,723 1.0487 0.00 0.25 5.22 0.43 0.25 0.25 0.000 0,015 4.89
77 0.14 0,008 3,716 1.0470 0.00 0.24 5.12 0.43 0.24 0.24 0.000 0,014 4.64
78 0.13 0,008 3,709 1.0453 4 0.00 0.23 5.03 0.43 0.23 0.23 0.000 0,014 4.40
79 0.12 0,007 3,703 1.0438 0.00 0.22 4.94 0.42 0.22 0.22 0.000 0,013 4.17
80 0.11 0,007 3,697 1.0423 0.00 0.20 4.86 0.42 0.20 0.20 0.000 0,012 3.96
81 0.11 0,006 3,691 1.0408 0.00 0.19 4.77 0.42 0.19 0.19 0.000 0,012 3.75
82 0.10 0,006 3,685 1.0394 0.00 0.18 4.69 0.42 0.18 0.18 0.000 0,011 3.56
83 0.09 0,006 3,680 1.0380 0.00 0.17 4.61 0.42 0.17 0.17 0.000 0,010 3.38
84 0.09 0,005 3,674 1.0367 0.00 0.17 4.53 0.42 0.17 0.17 0.000 0,010 3.21
10-YEAR HYDROGRAPH ROUTING
1 Of

0
0
• o
1 0
1
1 0
1 0
1 0 0
III
1 0
1
0
1 °0
1
1
1 O
1 0
O
1 o
1 0
2 1 0
a I CD -
re 1 CD
0 o w
U I CO I
0
I
0 I I
2 1 0o c o
1 0
O 1 a,
H I E o
z i= & 0_
w >
H 1 00 o a
w
d d 0
I '
a I o
w I ca
o [ 8 I— o II
1 co
•
` O
• O
` N
•
•
• O
• O
•
•
I 1 0
0 0 0 0 O O O
0 0 0 0 O O
6 4 C7 CV '- O
(II) a6e;S 1s13)mold

FORMULATING PRE-POST DEVELOPMENT HYDROGRAPHS
Utilize small watershed method&center-weighted storm(Malcom)
Return Period 25 year
I= 8.750 in/hr 25 year,Tc Intensity
Cpre 0.10 (Composite Rational C, See Drainage Area/Computations Map)
Cpost 0.81 (Composite Rational C, See Drainage Area/Computations Map)
A= 0.76 acre
A= 33,106 sf Rainfall 4.64 in (25 year,6 hour storm)
Qpre= 0.67 cfs PRE CN 490 S= 10.41 Q*= 0.50 in
Qpost= 5.39 cfs POST CN 91 S= 0.9 Q*= 3.63 in
Vol -Pre 1,393 cf 0.2*S: 2.0816327
Vol -Post 10,024 cf (If rainfall is less than 20%S, Q*=0)
Tpre 25 min
Tpost 22 min
Time Step 1 min
Time Q-pre Q-post
min cfs cfs
0 0.00 0.00
1 0.00 0.03
2 0.01 0.11
3 0.02 0.24
4 0.04 0.42
5 0.06 0.64
6 0.09 0.91
7 0.12 1.21
8 0.15 1.54
9 0.19 1.89
10 0.23 2.26
11 0.27 2.63
12 0.31 3.01
13 0.35 3.38
14 0.39 3.74
15 0.43 4.08
16 0.47 4.39
17 0.51 4.67
18 0.54 4.91
19 0.57 5.10
20 0.60 5.25
21 0.62 5.34
22 0.64 5.38
23 0.65 5.37
24 0.66 5.31
25 0.66 5.20
26 0.66 5.03
27 0.66 4.82
28 0.64 4.57
29 0.63 4.32
30 0.60 4.07
31 0.58 3.84
32 0.55 3.62
33 0.52 3.42
34 0.50 3.22
35 0.47 3.04
36 0.45 2.87
37 0.42 2.71
38 0.40 2.55
39 0.38 2.41
40 0.36 2.27
41 0.35 2.14
42 0.33 2.02
43 0.31 1.91
44 0.30 1.80
10-YEAR INFLOW
1 of 3

HYDROGRAPH ROUTING THROUGH WET POND
25-YEAR STORM Extrapolated Kp
FORMULAS FROM EC MANUAL 8.07.5 Manning Coefficient
Pipe Diam. Flow Area 0.015 0.025
Type Structure: Riser with Circular Drawdown Outlet and Barrel 2 0.0218 0.4542 1.2617
Orifice Equation:Q.CDA(2gh)°'s 3 0.0491 0.2645 0.7348
Pipe Flow Formula:Cl.a[2gh I 1+Km+KpL]°s 4 0.0872 0.1803 0.5007
Weir Flow Formula:Q=CLH''S 6 0.1963 0.1050 0.2916
Co(Orifice): 0.60 8 0.3489 0.0715 0.1987
Height Change,Weir to 2.00 ft Km 1.0 Standard 0.5451
Orifice Flow 10 0.0531 0.1476
C„„, 3.00 Kp 0.7348 (Table 8.07a) 12 0.7850 0.0417 0.1157
Primary Riser Diam 30.0 in. Length of Barre 20 ft 14 1.0685 0.0339 0.0942
Circum.of Riser 7.85 ft Barrel Diam. 3 in 15 1.2266 0.0309 0.0859
Area of Riser 4.91 ft2 Barrel Area: 0.05 ft2 2.5 0.0341 0.3373 0.9370
Riser Drawdown Outlet 2 in NOTE: Heights measured from normal pool elevation
Orifice Diam.
Number of Orifices 0
Riser Drawdown Outlet 0.00 ft5 Norval Pool Height= 0.00 R
Orifice Area
Existing Soil N/A
Min.Infiltration Rate 0.00 in/hr 1 Height of Riser weir= 1.00 ft 1
Vol.Lost to Infil. 0 cf/hr
Stage Storage Function:S=3,525 a Z 1.15
Riser Secondary Primary Riser Primary Riser Riser/Drawdown
Barrel Capacity Totatoutflow
Inflow Volume in Storage Stage Orifice Capacity Capaei y Capacity Outlet Flow Infill Vol Out Velocity
s(R of of ft Orifice Flow(cis] Weir Flow(cts) Orifice Flow fcf-' -.(cfs; (c/s) (cfa) allif
1 0.03 0,002 0,002 0.0012 #NUM! #NUM. #NUM 0.14 0.00 0.00 0.000 0,000
2 0.11 0,006 0,008 0.0050 #NUM! #NUM. #NUM 0.14 0.00 0.00 0.000 0,000 0.00
3 0.24 0,014 0,022 0.0122 #NUMI #NUM #NUM 0.14 0.00 0.00 0.000 0,000 0.00
4 0.42 0,025 0,047 0.0235 #NUMI #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
5 0.64 0,038 0,086 0.0394 #NUMI #NUM #NUM 0.16 0.00 0.00 0.000 0,000 0.00
6 0.91 0,054 0,140 0.0604 #NUMI #NUM #NUM 0.17 0.00 0.00 0.000 0,000 0.00
7 1.21 0,072 0,212 0.0868 0.00 #NUM #NUM 0.18 0.00 0.00 0.000 0,000 0.00
8 1.54 0,092 0,304 0.1188 0.00 #NUM #NUM 0.19 0.00 0.00 0.000 0,000 0.00
9 1.89 0,113 0,418 0.1565 0.00 #NUM #NUM 0.21 0.00 0.00 0.000 0,000 0.00
10 2.26 0,135 0,553 0.1998 0.00 #NUM #NUM 0.22 0.00 0.00 0.000 0,000 0.00
11 2.63 0,158 0,711 0.2486 0.00 #NUM #NUM 0.24 0.00 0.00 0.000 0,000 0.00
12 3.01 0,181 0,892 0.3027 0.00 #NUM #NUM 0.26 0.00 0.00 0.000 0,000 0.00
13 3.38 0,203 1,095 0.3618 0.00 #NUM #NUM 0.27 0.00 0.00 0.000 0,000 0.00
14 3.74 0,225 1,319 0.4255 0.00 #NUM #NUM 0.29 0.00 0.00 0.000 0,000 0.00
15 4.08 0,245 1,564 0.4934 0.00 #NUM #NUM 0.31 0.00 0.00 0.000 0,000 0.00
16 4.39 0,263 1,828 0.5649 0.00 #NUM #NUM 0.33 0.00 0.00 0.000 0,000 0.00
17 4.67 0,280 2,108 0.6394 0.00 #NUM #NUM 0.34 0.00 0.00 0.000 0,000 0.00
18 4.91 0,294 2,402 0.7164 0.00 #NUM #NUM 0.36 0.00 0.00 0.000 0,000 0.00
19 5.10 0,306 2,708 0.7951 0.00 #NUM #NUM 0.38 0.00 0.00 0.000 0,000 0.00
20 5.25 0,315 3,023 0.8749 0.00 #NUM #NUM 0.39 0.00 0.00 0.000 0,000 0.00
21 5.34 0,320 3,343 0.9550 0.00 #NUM #NUM 0.41 0.00 0.00 0.000 0,000 3.11
22 5.38 0,323 3,666 1.0347 0.00 0.15 4.41 0.42 0.15 0.15 0.000 0,009 8.90
23 5.37 0,322 3,979 1.1112 0.00 0.87 7.88 0.44 0.87 0.44 0.000 0,052 9.13
24 5.31 0,319 4,246 1.1756 0.00 1.73 9.90 0.45 1.73 0.45 0.000 0,104 9.30
25 5.20 0,312 4,453 1.2254 0.00 2.52 11.22 0.46 2.52 0.46 0.000 0,151 9.43
26 5.03 0,302 4,604 1.2614 0.00 3.15 12.08 0.46 3.15 0.46 0.000 0,189 9.51
27 4.82 0,289 4,704 1.2853 0.00 3.59 12.62 0.47 3.59 0.47 0.000 0,215 9.56
28 4.57 0,274 4,763 1.2993 0.00 3.86 12.93 0.47 3.86 0.47 0.000 0,231 9.58
29 4.32 0,259 4,791 1.3058 0.00 3.98 13.07 0.47 3.98 0.47 0.000 0,239 9.58
30 4.07 0,244 4,796 1.3070 0.00 4.01 13.10 0.47 4.01 0.47 0.000 0,240 9.57
31 3.84 0,230 4,786 1.3046 0.00 3.96 13.05 0.47 3.96 0.47 0.000 0,238 9.56
32 3.62 0,217 4,766 1.2998 0.00 3.87 12.94 0.47 3.87 0.47 0.000 0,232 9.54
33 3.42 0,205 4,739 1.2934 0.00 3.74 12.80 0.47 3.74 0.47 0.000 0,225 9.51
34 3.22 0,193 4,707 1.2860 0.00 3.60 12.64 0.47 3.60 0.47 0.000 0,216 9.48
35 3.04 0,183 4,674 1.2780 0.00 3.45 12.46 0.47 3.45 0.47 0.000 0,207 9.46
36 2.87 0,172 4,639 1.2697 0.00 3.30 12.27 0.46 3.30 0.46 0.000 0,198 9.43
37 2.71 0,162 4,603 1.2612 0.00 3.15 12.08 0.46 3.15 0.46 0.000 0,189 9.40
38 2.55 0,153 4,568 1.2527 4 0.00 2.99 11.88 0.46 2.99 0.46 0.000 0,180 9.37
39 2.41 0,145 4,533 1.2444 0.00 2.85 11.68 0.46 2.85 0.46 0.000 0,171 9.34
40 2.27 0,136 4,498 1.2362 0.00 2.70 11.49 0.46 2.70 0.46 0.000 0,162 9.31
41 2.14 0,129 4,465 1.2281 0.00 2.57 11.29 0.46 2.57 0.46 0.000 0,154 9.29
42 2.02 0,121 4,432 1.2203 0.00 2.44 11.09 0.46 2.44 0.46 0.000 0,146 9.26
43 1.91 0,115 4,400 1.2127 0.00 2.31 10.90 0.45 2.31 0.45 0.000 0,139 9.23
44 1.80 0,108 4,370 1.2054 0.00 2.19 10.71 0.45 2.19 0.45 0.000 0,132 9.21
45 1.70 0,102 4,340 1.1983 0.00 2.08 10.52 0.45 2.08 0.45 0.000 0,125 9.19
46 1.60 0,096 4,311 1.1914 0.00 1.97 10.34 0.45 1.97 0.45 0.000 0,118 9.16
47 1.51 0,091 4,284 1.1847 0.00 1.87 10.16 0.45 1.87 0.45 0.000 0,112 9.14
48 1.43 0,086 4,257 1.1783 0.00 1.77 9.98 0.45 1.77 0.45 0.000 0,106 9.12
49 1.35 0,081 4,231 1.1721 0.00 1.68 9.81 0.45 1.68 0.45 0.000 0,101 9.10
50 1.27 0,076 4,207 1.1662 0.00 1.60 9.63 0.45 1.60 0.45 0.000 0,096 9.08
51 1.20 0,072 4,183 1.1604 0.00 1.51 9.47 0.45 1.51 0.45 0.000 0,091 9.06
52 1.13 0,068 4,160 1.1548 0.00 1.44 9.30 0.44 1.44 0.44 0.000 0,086 9.04
53 1.07 0,064 4,137 1.1495 0.00 1.36 9.14 0.44 1.36 0.44 0.000 0,082 9.02
54 1.01 0,060 4,116 1.1443 0.00 1.29 8.98 0.44 1.29 0.44 0.000 0,078 9.00
55 0.95 0,057 4,096 1.1393 0.00 1.23 8.82 0.44 1.23 0.44 0.000 0,074 8.98
56 0.89 0,054 4,076 1.1345 0.00 1.16 8.67 0.44 1.16 0.44 0.000 0,070 8.97
57 0.84 0,051 4,057 1.1299 0.00 1.10 8.52 0.44 1.10 0.44 0.000 0,066 8.95
58 0.80 0,048 4,038 1.1255 0.00 1.05 8.37 0.44 1.05 0.44 0.000 0,063 8.94
59 0.75 0,045 4,020 1.1212 0.00 0.99 8.23 0.44 0.99 0.44 0.000 0,060 8.92
60 0.71 0,043 4,003 1.1170 0.00 0.94 8.08 0.44 0.94 0.44 0.000 0,057 8.91
61 0.67 0,040 3,987 1.1130 0.00 0.90 7.95 0.44 0.90 0.44 0.000 0,054 8.89
62 0.63 0,038 3,971 1.1092 0.00 0.85 7.81 0.44 0.85 0.44 0.000 0,051 8.88
63 0.60 0,036 3,956 1.1055 0.00 0.81 7.68 0.44 0.81 0.44 0.000 0,048 8.87
64 0.56 0,034 3,941 1.1019 0.00 0.77 7.54 0.44 0.77 0.44 0.000 0,046 8.85
65 0.53 0,032 3,927 1.0984 0.00 0.73 7.42 0.43 0.73 0.43 0.000 0,044 8.84
66 0.50 0,030 3,913 1.0951 0.00 0.69 7.29 0.43 0.69 0.43 0.000 0,041 8.83
67 0.47 0,028 3,900 1.0919 0.00 0.66 7.16 0.43 0.66 0.43 0.000 0,039 8.82
68 0.44 0,027 3,887 1.0888 0.00 0.62 7.04 0.43 0.62 0.43 0.000 0,037 8.81
69 0.42 0,025 3,875 1.0858 0.00 0.59 6.92 0.43 0.59 0.43 0.000 0,036 8.80
70 0.40 0,024 3,863 1.0829 0.00 0.56 6.81 0.43 0.56 0.43 0.000 0,034 8.79
71 0.37 0,022 3,852 1.0802 0.00 0.53 6.69 0.43 0.53 0.43 0.000 0,032 8.78
72 0.35 0,021 3,841 1.0775 0.00 0.51 6.58 0.43 0.51 0.43 0.000 0,031 8.77
73 0.33 0,020 3,830 1.0749 0.00 0.48 6.47 0.43 0.48 0.43 0.000 0,029 8.76
74 0.31 0,019 3,820 1.0724 0.00 0.46 6.36 0.43 0.46 0.43 0.000 0,028 8.75
75 0.30 0,018 3,810 1.0700 0.00 0.44 6.26 0.43 0.44 0.43 0.000 0,026 8.46
76 0.28 0,017 3,801 1.0677 1 0.00 0.42 6.15 0.43 0.42 0.42 0.000 0,025 8.05
77 0.26 0,016 3,792 1.0655 0.00 0.40 6.05 0.43 0.40 0.40 0.000 0,024 7.65
78 0.25 0,015 3,783 1.0634 0.00 0.38 5.95 0.43 0.38 0.38 0.000 0,023 7.28
79 0.23 0,014 3,775 1.0613 0.00 0.36 5.85 0.43 0.36 0.36 0.000 0,021 6.93
80 0.22 0,013 3,766 1.0593 0.00 0.34 5.75 0.43 0.34 0.34 0.000 0,020 6.59
81 0.21 0,013 3,758 1.0574 0.00 0.32 5.66 0.43 0.32 0.32 0.000 0,019 6.27
82 0.20 0,012 3,751 1.0555 0.00 0.31 5.57 0.43 0.31 0.31 0.000 0,018 5.97
83 0.19 0,011 3,744 1.0537 0.00 0.29 5.48 0.43 0.29 0.29 0.000 0,018 5.68
84 0.18 0,011 3,736 1.0520 0.00 0.28 5.39 0.43 0.28 0.28 0.000 0,017 5.41
10-YEAR HYDROGRAPH ROUTING
1 Of

O
O
IQ
0
T
O
O
O
O
11 O
O
O
co
O
O
O O
w
7
0
2 C
a
a 0 Ca
CL 00 a)
(-9 0 0 cn
•
o w
o
a_2 0 .c co
L
O I o 0
I— E o
Z I i= & 0_
w I 12
w I — 0 0
ClI I . o0
Q I 00
> I O a
N
0 II
I c)
1
•
` O
O
• O
S N
0
O
0
O
I I I ' 0
0 0 0 0 0 0 00
0 0 0 0 0 0 0
CO L(i 4 cri CV T 0
(ii) e6e4S `(sjo)mold

FORMULATING PRE-POST DEVELOPMENT HYDROGRAPHS
Utilize small watershed method&center-weighted storm(Malcom)
Return Period 50 year
I= 9.350 in/hr 50 year,Tc Intensity
Cpre 0.10 (Composite Rational C, See Drainage Area/Computations Map)
Cpost 0.81 (Composite Rational C, See Drainage Area/Computations Map)
A= 0.76 acre
A= 33,106 sf Rainfall 5.25 in (50 year,6 hour storm)
Qpre= 0.71 cfs PRE CN 490 S= 10.41 Q*= 0.74 in
Qpost= 5.76 cfs POST CN 91 S= 0.9 Q*= 4.23 in
Vol -Pre 2,040 cf 0.2*S: 2.0816327
Vol -Post 11,656 cf (If rainfall is less than 20%S, Q*=0)
Tpre 34 min
Tpost 24 min
Time Step 1 min
Time Q-pre Q-post
min cfs cfs
0 0.00 0.00
1 0.00 0.02
2 0.01 0.10
3 0.01 0.21
4 0.02 0.38
5 0.04 0.58
6 0.05 0.82
7 0.07 1.10
8 0.09 1.41
9 0.11 1.74
10 0.14 2.09
11 0.16 2.45
12 0.19 2.83
13 0.22 3.20
14 0.25 3.56
15 0.28 3.92
16 0.32 4.26
17 0.35 4.57
18 0.38 4.86
19 0.41 5.11
20 0.44 5.33
21 0.48 5.50
22 0.51 5.63
23 0.53 5.72
24 0.56 5.75
25 0.59 5.74
26 0.61 5.69
27 0.63 5.58
28 0.65 5.43
29 0.67 5.24
30 0.68 5.00
31 0.69 4.75
32 0.70 4.50
33 0.71 4.27
34 0.71 4.05
35 0.71 3.84
36 0.71 3.64
37 0.70 3.45
38 0.69 3.27
39 0.68 3.10
40 0.67 2.93
41 0.65 2.78
42 0.63 2.64
43 0.61 2.50
44 0.59 2.37
10-YEAR INFLOW
1 of 3

HYDROGRAPH ROUTING THROUGH WET POND
50-YEAR STORM Extrapolated Kp
FORMULAS FROM EC MANUAL 8.07.5 Manning Coefficient
Pipe Diam. Flow Area 0.015 0.025
Type Structure: Riser with Circular Drawdown Outlet and Barrel 2 0.0218 0.4542 1.2617
Orifice Equation:Q.C0A(2gh)°'s 3 0.0491 0.2645 0.7348
Pipe Flow Formula:Cl.a[2gh I 1+Km+KpL]°s 4 0.0872 0.1803 0.5007
Weir Flow Formula:Q=CLH''S 6 0.1963 0.1050 0.2916
Co(Orifice): 0.60 8 0.3489 0.0715 0.1987
Height Change,Weir to 2.00 ft Km 1.0 Standard 0.5451
Orifice Flaw 10 0.0531 0.1476
C„„, 3.00 Kp 0.7328 (Table 8.07a) 12 0.7850 0.0417 0.1157
Primary Riser Diam 30.0 in. Length of Barre 20 ft 14 1.0685 0.0339 0.0942
Circum.of Riser 7.85 ft Barrel Diam. 3 in 15 1.2266 0.0309 0.0859
Area of Riser 4.91 5° Barrel Area: 0.05 5° 2.5 0.0341 0.3373 0.9370
Riser Drawdown Outlet 2 in NOTE: Heights measured from normal pool elevation
Orifice Diam.
Number of Orifices 0
Riser Drawdown Outlet 0.00 0° Normal Pool Height= 0.00 ft
Orifice Area
Existing Soil N/A
Min.Infiltration Rate 0.00 in/hr 1 Height of Riser Weir 1.00 ft 1
Vol.Lost to loll. 0 cf/hr
Stage Storage Function:S=3,525 a Z 1.15
Riser Secondary Primary Riser Primary Ricer Riaer/fogs) wn
Barrel Capacity Total Outflow
Mk Inflow Volume in Storage Stage Orifice Capacity Gaped y Capaelry Outlet Flow Infill Vol Out Velocity
or of of # Orifice Flow(cfs) Weir Flow(cfs) Orifice Flow fcf-' ---(cfs; (c/s) (c/a) -
1 0.02 0,001 0,001 0.0011 #NUM. #NUM. #NUM 0.14 0.00 0.00 0.000 0,000
2 0.10 0,006 0,007 0.0046 #NUM. #NUM. #NUM 0.14 0.00 0.00 0.000 0,000 0.00
3 0.21 0,013 0,020 0.0112 #NUM #NUM #NUM 0.14 0.00 0.00 0.000 0,000 0.00
4 0.38 0,023 0,043 0.0215 #NUM #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
5 0.58 0,035 0,078 0.0362 #NUM #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
6 0.82 0,049 0,127 0.0556 #NUM #NUM #NUM 0.16 0.00 0.00 0.000 0,000 0.00
7 1.10 0,066 0,193 0.0800 #NUM #NUM #NUM 0.18 0.00 0.00 0.000 0,000 0.00
8 1.41 0,085 0,278 0.1097 0.00 #NUM #NUM 0.19 0.00 0.00 0.000 0,000 0.00
9 1.74 0,104 0,382 0.1448 0.00 #NUM #NUM 0.20 0.00 0.00 0.000 0,000 0.00
10 2.09 0,125 0,508 0.1854 0.00 #NUM #NUM 0.22 0.00 0.00 0.000 0,000 0.00
11 2.45 0,147 0,655 0.2314 0.00 #NUM #NUM 0.23 0.00 0.00 0.000 0,000 0.00
12 2.83 0,170 0,824 0.2827 0.00 #NUM #NUM 0.25 0.00 0.00 0.000 0,000 0.00
13 3.20 0,192 1,016 0.3390 0.00 #NUM #NUM 0.27 0.00 0.00 0.000 0,000 0.00
14 3.56 0,214 1,230 0.4003 I 0.00 #NUM #NUM 0.28 0.00 0.00 0.000 0,000 0.00
15 3.92 0,235 1,465 0.4661 0.00 #NUM #NUM 0.30 0.00 0.00 0.000 0,000 0.00
16 4.26 0,255 1,720 0.5359 0.00 #NUM #NUM 0.32 0.00 0.00 0.000 0,000 0.00
17 4.57 0,274 1,995 0.6095 0.00 #NUM #NUM 0.34 0.00 0.00 0.000 0,000 0.00
18 4.86 0,291 2,286 0.6862 0.00 #NUM #NUM 0.35 0.00 0.00 0.000 0,000 0.00
19 5.11 0,307 2,593 0.7656 0.00 #NUM #NUM 0.37 0.00 0.00 0.000 0,000 0.00
20 5.33 0,320 2,912 0.8470 0.00 #NUM #NUM 0.39 0.00 0.00 0.000 0,000 0.00
21 5.50 0,330 3,242 0.9298 0.00 #NUM #NUM 0.40 0.00 0.00 0.000 0,000 0.76
22 5.63 0,338 3,580 1.0136 0.00 0.04 2.75 0.42 0.04 0.04 0.000 0,002 8.85
23 5.72 0,343 3,921 1.0969 0.00 0.71 7.36 0.43 0.71 0.43 0.000 0,043 9.11
24 5.75 0,345 4,223 1.1702 0.00 1.65 9.75 0.45 1.65 0.45 0.000 0,099 9.31
25 5.74 0,345 4,469 1.2291 0.00 2.58 11.31 0.46 2.58 0.46 0.000 0,155 9.47
26 5.69 0,341 4,655 1.2735 0.00 3.37 12.36 0.46 3.37 0.46 0.000 0,202 9.57
27 5.58 0,335 4,787 1.3050 0.00 3.97 13.05 0.47 3.97 0.47 0.000 0,238 9.64
28 5.43 0,326 4,875 1.3257 0.00 4.38 13.49 0.47 4.38 0.47 0.000 0,263 9.68
29 5.24 0,314 4,926 1.3379 0.00 4.63 13.74 0.48 4.63 0.48 0.000 0,278 9.70
30 5.00 0,300 4,949 1.3432 0.00 4.74 13.85 0.48 4.74 0.48 0.000 0,284 9.70
31 4.75 0,285 4,950 1.3434 0.00 4.74 13.85 0.48 4.74 0.48 0.000 0,284 9.69
32 4.50 0,270 4,936 1.3400 0.00 4.67 13.78 0.48 4.67 0.48 0.000 0,280 9.67
33 4.27 0,256 4,911 1.3343 0.00 4.55 13.67 0.47 4.55 0.47 0.000 0,273 9.65
34 4.05 0,243 4,881 1.3271 0.00 4.41 13.52 0.47 4.41 0.47 0.000 0,264 9.62
35 3.84 0,230 4,847 1.3190 0.00 4.24 13.35 0.47 4.24 0.47 0.000 0,255 9.59
36 3.64 0,218 4,810 1.3103 0.00 4.07 13.17 0.47 4.07 0.47 0.000 0,244 9.56
37 3.45 0,207 4,772 1.3014 0.00 3.90 12.98 0.47 3.90 0.47 0.000 0,234 9.53
38 3.27 0,196 4,734 1.2924 0.00 3.73 12.78 0.47 3.73 0.47 0.000 0,224 9.50
39 3.10 0,186 4,697 1.2834 0.00 3.56 12.58 0.47 3.56 0.47 0.000 0,213 9.47
40 2.93 0,176 4,659 1.2746 0.00 3.39 12.38 0.46 3.39 0.46 0.000 0,203 9.44
41 2.78 0,167 4,623 1.2659 0.00 3.23 12.19 0.46 3.23 0.46 0.000 0,194 9.41
42 2.64 0,158 4,587 1.2574 0.00 3.08 11.99 0.46 3.08 0.46 0.000 0,185 9.38
43 2.50 0,150 4,553 1.2491 0.00 2.93 11.80 0.46 2.93 0.46 0.000 0,176 9.36
44 2.37 0,142 4,519 1.2411 0.00 2.79 11.61 0.46 2.79 0.46 0.000 0,167 9.33
45 2.25 0,135 4,486 1.2333 0.00 2.66 11.42 0.46 2.66 0.46 0.000 0,159 9.30
46 2.13 0,128 4,455 1.2257 4 0.00 2.53 11.23 0.46 2.53 0.46 0.000 0,152 9.28
47 2.02 0,121 4,424 1.2184 0.00 2.41 11.05 0.46 2.41 0.46 0.000 0,144 9.25
48 1.91 0,115 4,395 1.2113 0.00 2.29 10.87 0.45 2.29 0.45 0.000 0,137 9.23
49 1.81 0,109 4,366 1.2045 0.00 2.18 10.69 0.45 2.18 0.45 0.000 0,131 9.21
50 1.72 0,103 4,338 1.1978 0.00 2.07 10.51 0.45 2.07 0.45 0.000 0,124 9.18
51 1.63 0,098 4,312 1.1914 0.00 1.97 10.34 0.45 1.97 0.45 0.000 0,118 9.16
52 1.54 0,093 4,286 1.1852 0.00 1.88 10.17 0.45 1.88 0.45 0.000 0,113 9.14
53 1.46 0,088 4,261 1.1792 0.00 1.79 10.01 0.45 1.79 0.45 0.000 0,107 9.12
54 1.39 0,083 4,237 1.1734 0.00 1.70 9.84 0.45 1.70 0.45 0.000 0,102 9.10
55 1.31 0,079 4,214 1.1678 0.00 1.62 9.68 0.45 1.62 0.45 0.000 0,097 9.08
56 1.25 0,075 4,191 1.1624 0.00 1.54 9.53 0.45 1.54 0.45 0.000 0,093 9.06
57 1.18 0,071 4,169 1.1572 0.00 1.47 9.37 0.44 1.47 0.44 0.000 0,088 9.04
58 1.12 0,067 4,149 1.1521 0.00 1.40 9.22 0.44 1.40 0.44 0.000 0,084 9.03
59 1.06 0,064 4,128 1.1473 0.00 1.33 9.07 0.44 1.33 0.44 0.000 0,080 9.01
60 1.01 0,060 4,109 1.1425 0.00 1.27 8.92 0.44 1.27 0.44 0.000 0,076 8.99
61 0.95 0,057 4,090 1.1380 0.00 1.21 8.78 0.44 1.21 0.44 0.000 0,072 8.98
62 0.90 0,054 4,072 1.1336 0.00 1.15 8.64 0.44 1.15 0.44 0.000 0,069 8.96
63 0.86 0,051 4,054 1.1293 0.00 1.10 8.50 0.44 1.10 0.44 0.000 0,066 8.95
64 0.81 0,049 4,037 1.1252 0.00 1.04 8.36 0.44 1.04 0.44 0.000 0,063 8.93
65 0.77 0,046 4,021 1.1212 0.00 0.99 8.23 0.44 0.99 0.44 0.000 0,060 8.92
66 0.73 0,044 4,005 1.1173 0.00 0.95 8.10 0.44 0.95 0.44 0.000 0,057 8.91
67 0.69 0,041 3,989 1.1136 0.00 0.90 7.97 0.44 0.90 0.44 0.000 0,054 8.89
68 0.66 0,039 3,975 1.1100 1 0.00 0.86 7.84 0.44 0.86 0.44 0.000 0,052 8.88
69 0.62 0,037 3,960 1.1065 0.00 0.82 7.71 0.44 0.82 0.44 0.000 0,049 8.87
70 0.59 0,035 3,946 1.1032 0.00 0.78 7.59 0.44 0.78 0.44 0.000 0,047 8.86
71 0.56 0,033 3,933 1.0999 0.00 0.74 7.47 0.43 0.74 0.43 0.000 0,045 8.85
72 0.53 0,032 3,920 1.0968 0.00 0.71 7.35 0.43 0.71 0.43 0.000 0,043 8.83
73 0.50 0,030 3,908 1.0938 0.00 0.68 7.24 0.43 0.68 0.43 0.000 0,041 8.82
74 0.48 0,029 3,896 1.0908 0.00 0.64 7.12 0.43 0.64 0.43 0.000 0,039 8.81
75 0.45 0,027 3,884 1.0880 0.00 0.61 7.01 0.43 0.61 0.43 0.000 0,037 8.80
76 0.43 0,026 3,873 1.0852 0.00 0.59 6.90 0.43 0.59 0.43 0.000 0,035 8.79
77 0.40 0,024 3,862 1.0826 0.00 0.56 6.79 0.43 0.56 0.43 0.000 0,034 8.78
78 0.38 0,023 3,851 1.0800 0.00 0.53 6.69 0.43 0.53 0.43 0.000 0,032 8.77
79 0.36 0,022 3,841 1.0775 0.00 0.51 6.58 0.43 0.51 0.43 0.000 0,031 8.77
80 0.34 0,021 3,831 1.0751 0.00 0.49 6.48 0.43 0.49 0.43 0.000 0,029 8.76
81 0.33 0,020 3,822 1.0728 0.00 0.46 6.38 0.43 0.46 0.43 0.000 0,028 8.75
82 0.31 0,019 3,813 1.0706 0.00 0.44 6.28 0.43 0.44 0.43 0.000 0,027 8.59
83 0.29 0,018 3,804 1.0684 0.00 0.42 6.18 0.43 0.42 0.42 0.000 0,025 8.19
84 0.28 0,017 3,795 1.0663 0.00 0.40 6.09 0.43 0.40 0.40 0.000 0,024 7.82
10-YEAR HYDROGRAPH ROUTING
1 Of

0
O
0
O
O
O
0
rn
O
O
I 0
0
I
I O
0
0N- o
_ O
a s
Ce 0 4)
000
0)
! IP
0 I N I 1
2 I
o c _c
Q
I o c
Z 0
O ' E
I
E � o
Z 0
w I >
W I
0 0
0 I a �
< 1
w a I
1' o
0 0
in II
I co
I
I
I 0
O
O
I N
Ilit
I
♦
♦ O
♦♦` 1 O
•
I I I I T I I P
O O O O O O O O
O O O O O O O
6 6 4 cO N O
(U) e6e1S `(SJO) MOI J

FORMULATING PRE-POST DEVELOPMENT HYDROGRAPHS
Utilize small watershed method&center-weighted storm(Malcom)
Return Period 100 year
I= 9.910 in/hr 100 year,Tc Intensity
Cpre 0.10 (Composite Rational C, See Drainage Area/Computations Map)
Cpost 0.81 (Composite Rational C, See Drainage Area/Computations Map)
A= 0.76 acre
A= 33,106 sf Rainfall 5.88 in (100 year,6 hour storm)
Qpre= 0.75 cfs PRE CN 490 S= 10.41 Q*= 1.02 in
Qpost= 6.10 cfs POST CN 91 S= 0.9 Q*= 4.84 in
Vol -Pre 2,802 cf 0.2*S: 2.0816327
Vol -Post 13,352 cf (If rainfall is less than 20%S, Q*=0)
Tpre 45 min
Tpost 26 min
Time Step 1 min
Time Q-pre Q-post
min cfs cfs
0 0.00 0.00
1 0.00 0.02
2 0.00 0.09
3 0.01 0.19
4 0.01 0.34
5 0.02 0.53
6 0.03 0.75
7 0.04 1.01
8 0.06 1.30
9 0.07 1.61
10 0.09 1.94
11 0.11 2.28
12 0.13 2.64
13 0.15 3.01
14 0.17 3.37
15 0.19 3.73
16 0.21 4.08
17 0.24 4.42
18 0.26 4.73
19 0.29 5.02
20 0.32 5.29
21 0.34 5.52
22 0.37 5.72
23 0.40 5.87
24 0.42 5.99
25 0.45 6.07
26 0.47 6.10
27 0.50 6.09
28 0.52 6.03
29 0.55 5.94
30 0.57 5.80
31 0.59 5.62
32 0.61 5.40
33 0.63 5.16
34 0.65 4.91
35 0.67 4.68
36 0.69 4.45
37 0.70 4.23
38 0.71 4.03
39 0.72 3.84
40 0.73 3.65
41 0.74 3.47
42 0.75 3.31
43 0.75 3.15
44 0.75 2.99
10-YEAR INFLOW
1 of 3

HYDROGRAPH ROUTING THROUGH WET POND
100-YEAR STORM Extrapolated Kp
FORMULAS FROM EC MANUAL 8.07.5 Manning Coefficient
Pipe Diam. Flow Area 0.015 0.025
Type Structure: Riser with Circular Drawdown Outlet and Barrel 2 0.0218 0.4542 1.2617
Orifice Equation:Q.CDA(2gh)°'s 3 0.0491 0.2645 0.7348
Pipe Flow Formula:Cl.a[2gh I 1+Km+KpL]°s 4 0.0872 0.1803 0.5007
Weir Flow Formula:Q=CLH''S 6 0.1963 0.1050 0.2916
Co(Orifice): 0.60 8 0.3489 0.0715 0.1987
Height Change,Weir to 2.00 ft Km 1.0 Standard 0.5451
Orifice Flaw 10 0.0531 0.1476
C„„, 3.00 Kp 0.7348 (Table 8.07a) 12 0.7850 0.0417 0.1157
Primary Riser Diam 30.0 in. Length of Barre 20 ft 14 1.0685 0.0339 0.0942
Circum.of Riser 7.85 ft Barrel Diam. 3 in 15 1.2266 0.0309 0.0859
Area of Riser 4.91 ft2 Barrel Area: 0.05 ft2 2.5 0.0341 0.3373 0.9370
Riser Drawdown Outlet 2 in NOTE: Heights measured from normal pool elevation
Orifice Diam.
Number of Orifices 0
Riser Drawdown Outlet 0.00 ft0 Norval Pool Height= 0.00 h
Orifice Area
Existing Soil N/A
Min.Infiltration Rate 0.00 in/hr I Height of Riser Weir 1.00 ft 1
Vol.Lost to Infil. 0 cf/hr
Stage Storage Function:S=3,525 a Z 1.15
Riser Secondary Primary Riser Primary Riser Riser/Drawdown
Barrel Capacity Total Outflow
Inflow Volume in Storage Stage Orifice Capacity Capaei y Capacity Outlet Flow Infill Vol Out Velocity
of of ft Orifice Flow(ors) Weir Flow(cfs) Orifice Flow fcf-' ---(cfs; (c/s) (cfa) allif
1 0.02 0,001 0,001 0.0010 #NUM. #NUM. #NUM 0.14 0,00 0.00 0.000 0,000
2 0.09 0,005 0,007 0.0042 #NUM. #NUM. #NUM 0.14 0.00 0.00 0.000 0,000 0.00
3 0.19 0,012 0,018 0.0103 #NUM #NUM #NUM 0.14 0.00 0.00 0.000 0,000 0.00
4 0.34 0,021 0,039 0.0198 #NUM #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
5 0.53 0,032 0,071 0.0334 #NUM #NUM #NUM 0.15 0.00 0.00 0.000 0,000 0.00
6 0.75 0,045 0,116 0.0513 #NUM #NUM #NUM 0.16 0.00 0.00 0.000 0,000 0.00
7 1.01 0,061 0,176 0.0740 #NUM #NUM #NUM 0.17 0.00 0.00 0.000 0,000 0.00
8 1.30 0,078 0,254 0.1016 0.00 #NUM #NUM 0.18 0.00 0.00 0.000 0,000 0.00
9 1.61 0,096 0,350 0.1344 I 0.00 #NUM #NUM 0.20 0.00 0.00 0.000 0,000 0.00
10 1.94 0,116 0,467 0.1723 0.00 #NUM #NUM 0.21 0.00 0.00 0.000 0,000 0.00
11 2.28 0,137 0,604 0.2156 0.00 #NUM #NUM 0.23 0.00 0.00 0.000 0,000 0.00
12 2.64 0,159 0,762 0.2640 0.00 #NUM #NUM 0.24 0.00 0.00 0.000 0,000 0.00
13 3.01 0,180 0,943 0.3176 0.00 #NUM #NUM 0.26 0.00 0.00 0.000 0,000 0.00
14 3.37 0,202 1,145 0.3761 0.00 #NUM #NUM 0.28 0.00 0.00 0.000 0,000 0.00
15 3.73 0,224 1,369 0.4393 0.00 #NUM #NUM 0.29 0.00 0.00 0.000 0,000 0.00
16 4.08 0,245 1,613 0.5088 0.00 #NUM #NUM 0.31 0.00 0.00 0.000 0,000 0.00
17 4.42 0,265 1,878 0.5785 0.00 #NUM #NUM 0.33 0.00 0.00 0.000 0,000 0.00
18 4.73 0,284 2,162 0.6538 0.00 #NUM #NUM 0.35 0.00 0.00 0.000 0,000 0.00
19 5.02 0,301 2,464 0.7324 0.00 #NUM #NUM 0.36 0.00 0.00 0.000 0,000 0.00
20 5.29 0,317 2,781 0.8137 9 0.00 #NUM #NUM 0.38 0.00 0.00 0.000 0,000 0.00
21 5.52 0,331 3,112 0.8974 0.00 #NUM #NUM 0.40 0.00 0.00 0.000 0,000 0.00
22 5.72 0,343 3,455 0.9828 0.00 #NUM #NUM 0.41 0.00 0.00 0.000 0,000 8.75
23 5.87 0,352 3,808 1.0694 0.00 0.43 6.22 0.43 0.43 0.43 0.000 0,026 9.04
24 5.99 0,359 4,141 1.1504 0.00 1.37 9.17 0.44 1.37 0.44 0.000 0,082 9.28
25 6.07 0,364 4,423 1.2181 q 0.00 2.40 11.04 0.46 2.40 0.46 0.000 0,144 9.46
26 6.10 0,366 4,645 1.2711 0.00 3.33 12.31 0.46 3.33 0.46 0.000 0,200 9.59
27 6.09 0,365 4,811 1.3104 0.00 4.08 13.17 0.47 4.08 0.47 0.000 0,245 9.69
28 6.03 0,362 4,928 1.3382 0.00 4.63 13.75 0.48 4.63 0.48 0.000 0,278 9.75
29 5.94 0,356 5,008 1.3566 0.00 5.02 14.12 0.48 5.02 0.48 0.000 0,301 9.78
30 5.80 0,348 5,053 1.3676 0.00 5.25 14.33 0.48 5.25 0.48 0.000 0,315 9.80
31 5.62 0,337 5,075 1.3728 0.00 5.36 14.43 0.48 5.36 0.48 0.000 0,322 9.80
32 5.40 0,324 5,077 1.3734 0.00 5.38 14.44 0.48 5.38 0.48 0.000 0,323 9.79
33 5.16 0,310 5,064 1.3704 0.00 5.31 14.38 0.48 5.31 0.48 0.000 0,319 9.77
34 4.91 0,295 5,041 1.3648 0.00 5.19 14.27 0.48 5.19 0.48 0.000 0,311 9.75
35 4.68 0,281 5,010 1.3575 0.00 5.04 14.13 0.48 5.04 0.48 0.000 0,302 9.72
36 4.45 0,267 4,974 1.3492 0.00 4.86 13.97 0.48 4.86 0.48 0.000 0,292 9.69
37 4.23 0,254 4,937 1.3403 0.00 4.68 13.79 0.48 4.68 0.48 0.000 0,281 9.66
38 4.03 0,242 4,898 1.3311 0.00 4.49 13.60 0.47 4.49 0.47 0.000 0,269 9.63
39 3.84 0,230 4,859 1.3219 0.00 4.30 13.41 0.47 4.30 0.47 0.000 0,258 9.60
40 3.65 0,219 4,820 1.3126 0.00 4.12 13.21 0.47 4.12 0.47 0.000 0,247 9.57
41 3.47 0,208 4,781 1.3034 0.00 3.94 13.02 0.47 3.94 0.47 0.000 0,236 9.54
42 3.31 0,198 4,743 1.2944 0.00 3.76 12.83 0.47 3.76 0.47 0.000 0,226 9.51
43 3.15 0,189 4,708 1.2856 0.00 3.60 12.63 0.47 3.60 0.47 0.000 0,216 9.48
44 2.99 0,180 4,670 1.2770 0.00 3.44 12.44 0.47 3.44 0.47 0.000 0,206 9.45
45 2.85 0,171 4,635 1.2687 0.00 3.28 12.25 0.46 3.28 0.46 0.000 0,197 9.42
46 2.71 0,163 4,600 1.2605 0.00 3.13 12.06 0.46 3.13 0.46 0.000 0,188 9.40
47 2.58 0,155 4,567 1.2526 0.00 2.99 11.88 0.46 2.99 0.46 0.000 0,180 9.37
48 2.46 0,147 4,535 1.2449 0.00 2.86 11.70 0.46 2.86 0.46 0.000 0,171 9.35
49 2.34 0,140 4,504 1.2375 0.00 2.73 11.52 0.46 2.73 0.46 0.000 0,164 9.32
50 2.22 0,133 4,474 1.2303 0.00 2.60 11.34 0.46 2.60 0.46 0.000 0,156 9.30
51 2.12 0,127 4,444 1.2233 0.00 2.49 11.17 0.46 2.49 0.46 0.000 0,149 9.27
52 2.01 0,121 4,416 1.2165 1 0.00 2.37 11.00 0.46 2.37 0.46 0.000 0,142 9.25
53 1.92 0,115 4,389 1.2100 0.00 2.27 10.83 0.45 2.27 0.45 0.000 0,136 9.23
54 1.82 0,109 4,362 1.2036 0.00 2.16 10.66 0.45 2.16 0.45 0.000 0,130 9.21
55 1.74 0,104 4,337 1.1974 0.00 2.07 10.50 0.45 2.07 0.45 0.000 0,124 9.19
56 1.65 0,099 4,312 1.1914 0.00 1.97 10.34 0.45 1.97 0.45 0.000 0,118 9.17
57 1.57 0,094 4,288 1.1857 0.00 1.88 10.18 0.45 1.88 0.45 0.000 0,113 9.15
58 1.50 0,090 4,264 1.1801 0.00 1.80 10.03 0.45 1.80 0.45 0.000 0,108 9.13
59 1.42 0,085 4,242 1.1746 0.00 1.72 9.88 0.45 1.72 0.45 0.000 0,103 9.11
60 1.36 0,081 4,220 1.1694 0.00 1.64 973 0.45 1.64 0.45 0.000 0,099 9.09
61 1.29 0,077 4,199 1.1643 0.00 1.57 9,58 0.45 1.57 0.45 0.000 0,094 9.07
62 1.23 0,074 4,178 1.1593 0.00 1.50 9,43 0.45 1.50 0.45 0.000 0,090 9.06
63 1.17 0,070 4,158 1.1545 0.00 1.43 9.29 0.44 1.43 0.44 0.000 0,086 9.04
64 1.11 0,067 4,139 1.1499 0.00 1.37 9.15 0.44 1.37 0.44 0.000 0,082 9.02
65 1.06 0,063 4,121 1.1454 0.00 1.31 9.01 0.44 1.31 0.44 0.000 0,078 9.01
66 1.01 0,060 4,103 1.1411 0.00 1.25 8.88 0.44 1.25 0.44 0.000 0,075 8.99
67 0.96 0,057 4,085 1.1369 0.00 1.19 8.74 0.44 1.19 0.44 0.000 0,072 8.98
68 0.91 0,055 4,068 1.1328 0.00 1.14 8.61 0.44 1.14 0.44 0.000 0,068 8.96
69 0.87 0,052 4,052 1.1288 0.00 1.09 8.48 0.44 1.09 0.44 0.000 0,065 8.95
70 0.83 0,050 4,036 1.1250 0.00 1.04 8.36 0.44 1.04 0.44 0.000 0,062 8.94
71 0.79 0,047 4,021 1.1213 0.00 1.00 8.23 0.44 1.00 0.44 0.000 0,060 8.92
72 0.75 0,045 4,006 1.1177 0.00 0.95 8.11 0.44 0.95 0.44 0.000 0,057 8.91
73 0.71 0,043 3,992 1.1142 0.00 0.91 7.99 0.44 0.91 0.44 0.000 0,055 8.90
74 0.68 0,041 3,978 1.1108 0.00 0.87 7.87 0.44 0.87 0.44 0.000 0,052 8.89
75 0.64 0,039 3,964 1.1075 0.00 0.83 7.75 0.44 0.83 0.44 0.000 0,050 8.88
76 0.61 0,037 3,951 1.1044 0.00 0.79 7.64 0.44 0.79 0.44 0.000 0,048 8.86
77 0.58 0,035 3,939 1.1013 0.00 0.76 7.52 0.44 0.76 0.44 0.000 0,046 8.85
78 0.56 0,033 3,926 1.0983 0.00 0.73 7.41 0.43 0.73 0.43 0.000 0,044 8.84
79 0.53 0,032 3,915 1.0954 0.00 0.69 7.30 0.43 0.69 0.43 0.000 0,042 8.83
80 0.50 0,030 3,903 1.0926 0.00 0.66 7.19 0.43 0.66 0.43 0.000 0,040 8.82
81 0.48 0,029 3,892 1.0899 0.00 0.64 7.09 0.43 0.64 0.43 0.000 0,038 8.81
82 0.46 0,027 3,881 1.0873 0.00 0.61 6.98 0.43 0.61 0.43 0.000 0,036 8.80
83 0.43 0,026 3,871 1.0848 0.00 0.58 6.88 0.43 0.58 0.43 0.000 0,035 8.79
84 0.41 0,025 3,861 1.0823 0.00 0.56 6.78 0.43 0.56 0.43 0.000 0,033 8.79
10-YEAR HYDROGRAPH ROUTING
1 Of

O
O
- O
O
T
O
O
O
O)
O
O
•
co
O
O
0 0
I 0
a
a °
CL o aa)
C9 1 - • �°
0 1 I •
0 I 1
>- I 2 I 1
I O a_Zo co
p I o E 0
1 a)
0
w I I-: c�
a) 112
w I °o o a_1 0 o 0
a >
< I 0 0
> IIll = a
I
0 I O II
r I M
•
•
O
` O
• N
•
•
•
` O
O
O
O
I I 1 P
O O O O O O O O O
O O O O O O O O
f: CO iri 4 M N T O
(ii) a6e4S `(sjo)mold

d
v
2
c
c as
Cr
o §
fl § up
<
c
E
0
a)
2
\ - 0 % p
- C
2 §
\ >
2
4.4 o \
C ® � c \
g ] & ra
m e c
c / � � -
0 2 2 -0 ^ / 2 (5
/ kk ,_ a \
E § \ / 2 - m g g 2
111 k y - / ; \ IA VI U u q- "
0 \U § - k
2 VI x al \ \ / / • % % 2 j k ® CD b q
u » = d o w m a m o - Q . j q
g 6 \
U [ 0_ e U = < d i i i , i i §
E ° / ) / (5
C k k C ® §
,_ § 0 ( cc k 0.
0
0- ru
» -0 a) Q = 7 c
o c e ) a g
D 2 0 \ ƒ ƒ \ < E m
{ u 0 u / 2 / 0
2 0 a) / / ) \ 3 2
0 in 5 I- 0 0 ° Q d
0v /
\ § ) 7 ° B
\ < c v
.. c
P o § 3
c {
o I ¥
_ \ et
e
0 o o§ LLI $
§ #) q
0 0 L §
d CI
m tt
/
«

Selection of Sediment Control Measure
0.76 Total Drainage Area User entry
Okay Temporary Sediment Trap Calculated Value
Okay Skimmer Sediment Basin
Okay Sediment Basin
0.76 Disturbed Area (Acres)
4.86 Peak Flow from 10-year Storm (cfs)

df
Temporary Sediment Trap
Okay
0.76 Disturbed Area (Acres)
4.86 Peak Flow from 10-year Storm (cfs)
2736 Required Volume ft3
2117 Required Surface Area ft2
32.5 Suggested Width ft
65.1 Suggested Length ft
33 Trial Top Width at Spillway Invert ft
66 Trial Top Length at Spillway Invert ft
3 Trial Side Slope Ratio Z:1
3.5 Trial Depth ft (1.5 feet below grade + 2 to 3.5 feet above grade)
12 Bottom Width ft
45 Bottom Length ft
540 Bottom Area ft2
4499 Actual Volume ft3 Okay
2178 Actual Surface Area ft2 Okay
5 Trial Weir Length ft
0.5 Trial Depth of Flow ft
5.3 Spillway Capacity cfs Okay

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 1/9/2023
Checked By: JEH 1/9/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. sed trap outlet
Total Drainage Area (acres) 0.76
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified muumtuu tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide fiat areas with no defined channel are assumed
to have a mourn unn tailwater condition unless reliable flood stage elevations
,how otherwise.
Equivalent Outlet diam., Do (in.) 21
Tailwater depth (in.) 0.5
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 4.86
Velocity (ft./s) 1.94
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d5,,riprap size and minimum apron length
(L). The d,c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.4
Minimum apron length, La (ft.) 10
Apron width at pipe outlet (ft.) 5.25 5.25
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 11.75 1.75
Step 4. Determine the maximum stone diameter:
dmax = '1.5xd50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.6 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x dr,„
Minimum TW Maximum TW
Apron Thickness(ft.) 0.9 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length. La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and alone channel banks until stability is assured. Keep the
apron as straight as possible and alien it with the flow of the receiving stream
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix S.05). Where overfalls exist at
pipe outlets or flows are excessive. a plunge pool should be considered. see
page 8.06.8.

Temporary Diversion Swale 01C
PHALANX CROSSFIT
OBJECTIVE: Verify Capacity of Diversion Ditch Based Upon Q10 storm event.
Check that swale will non-erosively pass the Q10 storm event
SOLUTIONS: Mannings Flow Equation
RUNOFF CONDITIONS c: A(ac): 110(cfs):
0.81 0.76 7.90
Q10= 4.86 cfs
MAXIMUM d= 0.9400 ft (min.flow depth for Q10 storm) A= 2.65 FTA2
Slope Condition P= 5.95 FT
n= 0.058 (computed) R= 0.45
B= 0 ft(min.width) Q10 Storm= 4.87 CFS
Z Left= 3 :1(Side Slope) V10 Storm= 1.84 FPS
Z Right= 3 :1(Side Slope)
Avg.S= 0.015000 ft/ft(avg.slope) W= 5.64 FT
USE 6"HIGH BERM,2'TOP WIDTH,3'BOTTOM WIDTH
SHEAR STRESS: T= Shear Stress Y= 62.4 PCF
T= 0.880 PSF d= 0.94 FT
S= 0.02 FT/FT
RECOMMENDED LINING: Seed and Mulch With Contractor's Blend and Install Excelsior Matting or Equivalent
SAY:1'DEPTH,6'NATURAL FLOW SPREAD AT TERMINUS
TERMINOLOGY:
Q= Peak Discharge,(CFS) A= Cross-Sectional Area of Flow,(FT^2)
V= Permissible Velocity,(FPS) P= Wetted Perimeter of the Flow,(FT)
d= Maximum Depth of Water,(FT) R= Hydraulic Radius,(FT)
Vt=Trial Velocity,(FPS) S= Slope of the Channel,(FT/FT)
n= Manning's"n"Coefficient Q= Discharge,(CFS)
V*R= Product of Velocity and Hydraulic Radius V= Velocity,(FPS)
B= Bottom Width of Channel,(FT) W= Top Width of Water in Channel,(FT)
Z= Side Slope of Channel (Z:1) Y= Specific Weight of Water(62.4 PCF)
CHANNEL LINING:
With velocities less than 2 f/s use Seed and Mulching
With velocites greater than 2 f/s use Temporary Ditch Liner
:if T<1 then use Coir Wattle against silt fence
:if T>1 then use other lining

s awwoo .0 }
k N
co co
CV CV ugewg in
co o m o c
11 Ry ,�MeH m •
\&
§ o Almo n CO
_
• / \ / 2 / y i
_ _ \ & > / 2
W n n j % Co E ° ® m
E 7 o \ / 11 2
Z _ i \ E } /
/ \ 3 %
\ 66 § HI-
\ § § O
e ) a - - 2
•
\ W ` .- § °
= E > 5 - / §
O o a _ < e
02 o j gyy -
I / r
< §
cc e
\ _ o : \ II ii \ 0 co
~ /
2 o )I o \ co
g » 1 °` c 0
, 0 in \
5 \ \ ; \ a C \
I z z = &
j o I _ _ 2 _ K
co I <in . 7 /
R \ / § § ) /
o = . LT, 0
§
z w
2 } - w § w § w
0 _ _ N § 30 U) §
< t \ = n ■ W c o e 0 ƒ
e % 2 ) Ce w < 0
m = « _ & z
2 w (
0 ' o 0
F o u_ / - < z
co . 0 } w
; H _II 0 \ $ 0 )
\ W o CC
G o
2 r e f N k x ) } i
\ ) § \ ƒ k \ CO 2 § ^ j ( 0 < ) (
q 2 % § 2 W £ z D E CO + / )
7 § \ z — ƒ 0 0 - / / § Z . z
§ 0 < w { ( « U ` X -I ) j 0 } / }
C.) a a = 0 < o f a 2 3 = 3 \ ) _
x © o p _ 2 k m = a w + 0 J 6 +
@ c a u o 0 2 0 y N a- 0- e ntu e m z ? o < z z § < _ = f ? / ƒ m / V w
e 3 ) $ § o = O o 0 , ƒ , ± \ , II
/ E W ( § o o } - / _ D u. e ) / j u D
§ W \
- a r , r = w =
< ° k S1HS j Eo

WET POND STAGE-STORAGE BELOW PERMANENT POOL
FOREBAY ONLY
WET POND 01
Project# PHALANX CROSSFIT
Date: 5/19/2023 rev 7/13/23
Evaluation By: JEH
OBJECTIVE: Determine volumes below permanent pool
GIVEN:
Location: Spout Springs,NC
Watershed Area: 0.76
Accum.Storage(cu.
Contour(ft-MSL): Area(sf) Inc.Vol(cu.ft) ft) Stage(ft)
367.50 0,000 0,000 0,000 0.00
368.0 0,125 0,031 0,031 0.50
368.5 0,201 0,082 0,113 1.00 ACTUAL AVAILABLE STORAGE BELOW
369.0 0,297 0,125 0,237 1.50 PERMANENT POOL
370.0 0,540 0,419 0,656 2.50
370.5 0,690 0,308 0,963 3.00
MAIN POOL VOLUME: 6,128 cf %OF MAIN POOL: 15.72% 0co�'ESS C�/A,,-,
O O'I/.....A' 9
AVG.DEPTH MAIN POOL: 3.01 ft Q� _
367.50 IS TOP OF SEDIMENT STORAGE IN THE FOREBAY ! E•
•35.1 •
TOTAL VOLUME BELOW PERMANENT POOL 9A.:, GINEe'�P�o
Contour(ft-MSL): Area(sf) ' Off''_••H\,\, .
00
364.5 165 HILLIARD -
368.0 1,235 ENGINEERING 7/16/2023
368.5 1,480 3417 Winterwind Circle, Sanford, NC 27330
369.0 1,754 [phone]
370.0 2,376 NC No. P-0836
370.5 2,728
2,038 IS SURFACE AREA OF THE MAIN PERMANENT POOL

PHALANX CROSSFIT
SURFACE AREA AND DEPTH REQUIRED FOR MAIN POOL
EQUATION 2
WET POND 01
TABLE 1 PIEDMONT AND MOUNTAIN SA/DA TABLE TABLE 1 PIEDMONT AND MOUNTAIN SA/DA T
INTERPOLATION (3 ft) INTERPOLATION (4 ft)
Known Lower Percent Impervious: 80 Known Lower Percent Impervious: 80
Known Upper Percent Impervious: 90 Known Upper Percent Impervious: 90
Known Lower SA/DA: 2.92 Known Lower SA/DA: 2.41
Known Upper SA/DA: 3.25 Known Upper SA/DA: 2.64
Computed Impervious: 88.00 Computed Impervious: 88.00
Unknown Target SA/DA: 3.18 Unknown Target SA/DA: 2.59
TABLE 1 PIEDMONT AND MOUNTAIN SA/DA TABLE ,,,,,,,,,,,
INTERPOLATION (Avg. Depth of Permanent Pool) .s�:\N••CA/�0",
Known Lower Average Depth: 3 „-�� 0 ESS/04 by'=;-
Known Upper Average Depth: 4 r Q� 9�% -
Known Lower SA/DA: 2.92 = E' •
Known Upper SA/DA: 2.41 •35-. •
Computed Depth: 3.01 --v;• :'o
Unknown Target SA/DA: 2.91 - 'p..••./Y.c NF ..\p�.'
Min.Surface Area Required for Main Pool Area:
SA/DA: 2.91 7/16/2023
Drainage Area to SCM: 32,944 sf ��
Min. Surface Area Req'd: 960 sf
Surface Area Provided: 2,038 sf HILLIARD
ENGINEERING
Main Pool Volume: 6,128 cf 3417 Winterwind Circle, Sanford, NC 27330
Main Pool Surface Area: 2,038 sf [phone]
Main Pool Ave. Depth: 3.01 NC No. P-0836

WET POND STAGE-STORAGE FUNCTION
Project# PHALANX CROSSFIT
Date : 12/6/2022
Evaluation By: JEH
DESIGN STORM: 10-year
check 25,50,100
OBJECTIVE: Evaluate proposed Wet Pond in which storage exists from permanent pool elevation
GIVEN:
Location: Spout Springs, NC
Watershed Area: 0.76
Accum. Storage
Contour(ft-MSL): Area (sf) Inc.Vol (cu.ft) (cu.ft) Stage (ft) In Z In S Est. Stage (ft)
370.5 2,728 0,000 0,000 0.00 0.000 0.000 0.000
- — ACTUAL AVAILABLE STORAGE
371.0 3,554 1,571 1,571 0.50 -0.693 7.359 0.500
- — ABOVE PERMANENT POOL
371.5 4,206 1,940 3,511 1.00 0.000 8.164 1.000
—In intercept= 8.1635 Ks= 3,511
exponent= 1.1605 b= 1.16 ;,,_RAN CARO /�
o •''ESS%�.�y"
p_c„ - -1 nnnnnn cO
1,35: • _
HILLIARD = r o
ENGINEERING „;7'A;•�NGINE �'.P�'`
3417 Winterwind Circle, Sanford, NC 27330 ,,.O���E......
Ns�\\''
[phone] "'
NC No. P-0836 7/16/2023
Page 7

Linear Form of Stage-Storage Data
20.000 -
18.000 -
16.000 -
14.000 -
12.000 -
10.000 -
8.000 •
6.000 -
4.000 -
2.000 -
0.000
0.00 0.50 1.00 1.50 2.00
Stage Storage Function: S= Ks*Zb
Stage-Storage Function for Pond Area: S= 3,511 * Z 1.16
Page 8

PHALANX CROSSFIT
WET POND TEMPORARY VOLUME DRAWDOWN ORIFICE AND TIME
Time for the temporary volume related to the 1 yr,24 hr storm to drawn down provided a given orifice diameter
Invert for drawdown outlet 370.5 MSL
Elevation of Primary Spillway 371.5 MSL
Head on Orifice 1 FT
Design Volume(Actual Volume Acquired in Pond,NOT MINIMUM REQUIRED VOLUME) 3,511 cu.ft
Qo=CDxAx(2gh)^1/2
Diam(in) 0.5 Diam(in) 0.75 Diam(in) 1 Diam(in) 2 Diam(in) 4 Diam(in) 6
CD: 0.58 CD: 0.58 CD: 0.58 CD: 0.58 CD: 0.58 CD: 0.58
A(sq ft): 0.001363538 A(sq ft): 0.003067962 A(sq ft): 0.005454154 A(sq ft): 0.021816616 A(sq ft): 0.087266463 A(sq ft): 0.196349541
2g(ft/s2): 64.4 2g(ft/s2): 64.4 2g(ft/s2): 64.4 2g(ft/s2): 64.4 2g(ft/s2): 64.4 2g(ft/s2): 64.4
Ho(ft): 0.333 Ho(ft): 0.333 Ho(ft): 0.333 Ho(ft): 0.333 Ho(ft): 0.333 Ho(ft): 0.333
Qo(cfs): 0.00 Qo(cfs): 0.01 Qo(cfs): 0.01 Qo(cfs): 0.06 Qo(cfs): 0.23 Qo(cfs): 0.53
Drain Time Drain Time Drain Time Drain Time Drain Time Drain Time
(min): 15969.89 (hrs): 7097.73 (hrs): 3992.47 (hrs): 998.12 (hrs): 249.53 110.90
(hrs):
Drain Time Drain Time Drain Time Drain Time Drain Time Drain Time
(hrs): 266.16 (hrs): 118.30 (hrs): 66.54 (hrs): 16.64 (hrs): 4.16 1.85
(hrs):
Drain Time Drain Time Drain Time Drain Time Drain Time Drain Time
(days): 11.09 (days): 4.93 (days): 2.77 (days): 0.69 (days): 0.17 0.08
(days):
RESULTS: USE 3/4"ORIFICE
HILLIARD 7�• -1
ENGINEERING / ; : F,y'
x<5
3417 Winterwind Circle,Sanford,NC 27330 a �Cv
[phone] J`9,c fl'/,� ,-.
\\-\•\,r
7/16/2023

PHALANX CROSSFIT
D S
TOTAL
Pipe Dia. Velocity Discharge Discharge NUMBER OF CAPACITY
(Inches) Pipe Slope (fps) (gpm) (cfs) PIPES (cfs)
PIPE ID C I (in/hr) A(ac) Q(cfs) Capacity
o.k? Notes
DRIVEWAY CULVERT 36 0.660% 7.67 fps 24,319 54.19 1 54.19 0.5 8.75 12.37 54.12 Yes 25-yr storm
ON-SITE PIPING 15 0.700% 4.40 fps 2,426 5.40 1 5.40 0.81 8.75 0.76 5.39 Yes 25-yr storm
3 1.300% 2.05 fps 45 0.10 1 0.10
HILLIARDi. a kI- v��.
ENGINEERING = 'E
35
3417 Winterwind Circle,Sanford,NC 27330 .. 9'S' 'o
[phone] ''-- . .!I;GINE;:e'' P
NC No.P-0836 �� E. � '
7/16/2023

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 7/16/2023
Checked By: JEH 7/16/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs
Id. Inlet of Ex. 24" Culvert Downstream of Driveway
Total Drainage Area (acres) 12.37
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is greater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Pipe diam., Do (in.) 24
Tailwater depth (in.) 12
Minimum/Maximum tailwater? Max TW (Fig. 8.06b) c x Q10 x A
Discharge (cfs) 48.47 (0.5x7.90x12.37)
Velocity (ft./s) 15.44
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.92
Minimum apron length, La (ft.) 25
Apron width at pipe outlet (ft.) 6 6
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 27 2
Step 4. Determine the maximum stone diameter:
dmax 1.5 x d50
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 1.38 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x dr,a,
Minimum TW Maximum TW
Apron Thickness(ft.) 2.07 0
Step 6. Fit the riprap apron to the site by making it level for the minimum
length, La. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of iipiap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive, a plunge pool should be considered, see
page 8.06.8.
,sN CAR°,,
0 ESS/0;r••
HILLIARD ' Q� , =
ENGINEERING = E' •
-
• 135: I
3417 Winterwind Circle, Sanford, NC 27330
•�a
[phone] ,�,NGINEF:�'"P<
NC No. P-0836 GD 'E'
7/16/2023

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: JEH 11/29/2022
Checked By: JEH 7/13/2023
Company: Hilliard Engineering, PLLC
Project Name: Phalanx Crossfit
Project No.: HC2217
Site Location (City/Town) Spout Springs DISCHARGE TOO
Id. 02 -SCM Outlet LOW TO SHOW ON
Total Drainage Area (acres) 0.76 CHART
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter. it is classified minimum tailwater condition.
If it is g-eater than half the pipe diameter. it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Pipe diam., Do (in.) 3
Tailwater depth (in.) 0
Minimum/Maximum tailwater? Min TW (Fig. 8.06a)
Discharge (cfs) 0.48
Velocity (ft./s) 9.8
Step 2. Based on the tailwater conditions determined in step 1. enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(La). The d;c size is the median stone size in a well-graded riprap apron.
Step 3. Determine apron width at the pipe outlet. the apron shape. and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d50, (ft.) 0.2
Minimum apron length, La (ft.) 7
Apron width at pipe outlet (ft.) 0.75 0.75
Apron shape Trapezoidal Trapezoidal

Apron width at outlet end (ft.) 7.25 0.25
Step 4. Determine the maximum stone diameter:
d�*'ax 1.5 x dF0
Minimum TW Maximum TW
Max Stone Diameter, dmax (ft.) 0.3 0
Step 5. Determine the apron thickness:
Apron thickness = 1.5 x d"„
Minimum TW Maximum TW
Apron Thickness(ft.) 0.45 0
Step 6. Fit the riprap apron to the site by making it level for the nunimuin
length, La_ from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along chaiumel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary (Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive, a plunge pool should be considered. see
page 8.06.8_