20200967 Ver 2_Drainage_Report_20201113

Hydraulic Calculations
FOR
Davis Park East- Pod B
DURHAM, NORTH CAROLINA
SUBMITTAL
JULY 14, 2020
REVISED
NOVEMBER 6, 2020
Kimley>>)Horn
300 Morris St., Suite 200
Durham, NC 27701
NC LICENSE # F-0102

Storm Water System Design
The storm water systems are designed to meet North Carolina Department of
Transportation(NCDOT) hydraulic design standards. The inlet spacing is based on
limiting the spread at each inlet to 6' encroachment into the travel lane during 4 in/hr.
The pipes were sized based on the 10-year event.
We have included the storm drain profile for this project and is attached separately.

CREATE DATE: 7/7/2020 INLET COMPUTATION SHEET
REV. DATE:
I.D. NO.: Davis Park East Pod B PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION I ROADWAY RUNOFF _ INLET
w H o Z Lu
0 w d Ti- J w K wH.J Q ww OHIXEt z z H O O C7 t, LL u_ J reQ 0 > ❑ 4 cog mw w O w H
w H M co o . w - uj z O € Q = _ ❑ QO JQ < �o u' u)
REMARKS
U H
co 2z H LL. E > g nN Qw zw wz z _ O , 6Eg , O ' w � a aw
� ce ❑ 0 I 0 w
co HZ Jco 0 OO oQ O O Z ❑ LL c❑ ¢ Ogf a z2 M.
} 2J
< w❑ w ixU D.A. C Tc I QD.A. QC Q Q A.+Qc QI(mx) QB
101 0102 L 20+50 62 Lt 374.00 0.033 0.330 0.07 0.30 2.0 4.0 0.1 0.0 0.1 0.9 0.1 0.0
106 0105 L 20+65 33 Rt 370.31 0.033 0.058 0.09 0.80 2.0 4.0 0.3 0.0 0.3 1.3 0.3 0.0
106 0104 L 20+65 5 Rt 372.18 0.033 0.056 0.15 0.88 2.0 4.0 0.5 0.1 0.6 2.4 0.6 0.0 103
106 0103 L 20+45 5 Rt 371.50 0.033 0.061 0.03 0.88 2.0 4.0 0.1 0.0 0.1 1.2 0.1 0.0
110 0109 L 21+85 32 Rt 375.08 0.033 0.034 0.14 0.72 2.0 4.0 0.4 0.0 0.4 1.8 0.4 0.0 105
110 0108 L 21+85 CL 376.25 0.033 0.034 0.22 0.82 2.0 4.0 0.7 0.0 0.7 3.6 0.7 0.1 104
110 0114 L 23+50 32 Rt 380.66 0.034 0.031 0.21 0.72 2.0 4.0 0.6 0.0 0.6 2.2 0.6 0.0 109
110 0107 L 21+85 52 Lt 376.75 0.033 0.330 0.11 0.47 2.0 4.0 0.2 0.0 0.2 1.2 0.2 0.0
110 0113 L 23+50 6 Lt 381.92 0.034 0.031 0.06 0.80 2.0 4.0 0.2 0.1 0.3 2.7 0.3 0.0 108
110 0119 L 25+83 32 Rt 391.31 0.048 0.020 0.05 0.81 2.0 4.0 0.2 0.0 0.2 1.3 0.2 0.0 114
110 0111 L 22+90 49 Lt 381.10 0.033 0.330 0.09 0.58 2.0 4.0 0.2 0.0 0.2 1.3 0.2 0.0
110 0115 L 24+00 6 Lt 383.69 0.039 0.020 0.17 0.79 2.0 4.0 0.5 0.0 0.5 4.3 0.4 0.1 113 Spread as low as possible
110 0120 L 25+83 48 Rt 390.05 0.048 0.330 0.06 0.30 2.0 7.4 0.1 0.0 0.1
110 0121 L 26+36 32 Rt 393.98 0.048 0.017 0.11 0.85 2.0 4.0 0.4 0.0 0.4 1.9 0.4 0.0 119
110 0112 L 23+90 66 Lt 384.25 0.038 0.330 0.38 0.34 2.0 4.0 0.5 0.0 0.5 1.7 0.5 0.0
110 0116 L 25+55 6 Lt 390.35 0.048 0.015 0.00 0.38 2.0 4.0 0.0 0.0 0.0 0.5 0.0 0.0 115
110 0122 L 26+36 5 Lt 394.67 0.048 0.020 0.02 0.90 2.0 4.0 0.1 0.0 0.1 1.8 0.1 0.0 119
110 0117 L 25+55 32 Lt 390.11 0.048 0.015 0.02 0.83 2.0 4.0 0.1 0.0 0.1 1.2 0.1 0.0 115
110 0123 L 27+55 5 Lt 398.80 0.017 0.020 0.03 0.90 2.0 4.0 0.1 0.0 0.1 2.8 0.1 0.0 122 DI in turn lane
110 0118 L 25+78 32 Lt 391.05 0.048 0.020 0.22 0.88 2.0 4.0 0.8 0.0 0.8 3.2 0.7 0.0 117
128 0127 L 30+50 25 Rt 392.63 0.011 0.030 0.00 0.00 0.0 0.1 0.0 0.1 Collar
128 0133 L 30+48 6 Rt 397.18 I 0.011 0.030 0.02 0.81 2.0 4.0 0.1 0.0 0.1 2.1 0.1 0.0 130
Page 1 of 4 Printed 11/3/2020

CREATE DATE: 7/7/2020 INLET COMPUTATION SHEET
REV. DATE:
I.D. NO.: Davis Park East Pod B PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION ROADWAY RUNOFF INLET
w i- o z w w Ti-- w w
SI • w OHIXEt Z Z H O O O t, W LL E -J reQ 0 > ❑ cog DW W O W I W J QLL B Q s QK OQ Qocow � M co o
REMARKS� zzwzw .= Ur rx � � aaWcU ~2z I- L E j a ' fn Qw W Z Om Eg Ho wR
� Et 0 1 0 w
HZJco 0
OO o < O O Z ❑ LL c❑ ¢ Ogf an Z2 M.
} z1
u < W❑ W ceU D.A. C Tc I QD.A. QC Q Q+Qc Ql(mx) QB
I
128 0125 L 30+45 39 Lt 395.66 0.011 0.030 0.06 0.90 2.0 4.0 0.2 0.0 0.2 1.8 0.2 0.0 129
128 0134 L 30+25 6 Rt 397.43 0.011 0.030 0.11 0.83 2.0 4.0 0.4 0.0 0.4 3.7 0.3 0.0 133 Allowable spread 3.75'
128 0124 L 30+00 43 Lt 396.00 0.011 0.030 0.15 0.90 2.0 4.0 0.5 0.0 0.5 3.2 0.5 0.0 125
128 0126 L 30+42 61 Lt 393.50 0.011 0.330 0.38 0.32 2.0 1.1 0.1 0.0 0.1
207 0206 L 34+44 31 Rt 388.15 0.044 0.006 0.04 0.72 2.0 4.0 0.1 0.0 0.1 1.4 0.1 0.0 218
207 0205 L 34+02 32 Rt 389.70 0.044 0.015 0.05 0.72 2.0 4.0 0.1 0.0 0.1 1.3 0.1 0.0 206
207 0238 L 34+49 5 Lt 388.25 0.044 0.014 0.17 0.81 2.0 4.0 0.6 0.0 0.6 5.4 0.4 0.1 219 S ucture squired a to a on fo c oss pipe connec ty,sp sad depth s<7 incn.
207 0204 L 33+48 32 Rt 391.72 0.034 0.020 0.13 0.72 2.0 4.0 0.4 0.0 0.4 2.0 0.4 0.0 205
207 0208 L 34+56 65 Lt 387.07 0.044 0.006 0.39 0.38 2.0 0.9 0.1 0.0 0.1
207 0203 L 33+48 6 Lt 392.46 0.034 0.001 0.00 0.41 2.0 4.0 0.0 0.0 0.0 2.8 0.0 0.0 238
207 0202 L 32+79 6 Lt 393.93 0.019 0.015 0.00 0.41 2.0 4.0 0.0 0.0 0.0 0.6 0.0 0.0 203
207 0131 L 31+90 6 Rt 395.45 0.011 0.016 0.02 0.74 2.0 4.0 0.1 0.0 0.1 2.9 0.1 0.0 204
207 0201 L 32+79 32 Lt 393.70 0.019 0.015 0.10 0.81 2.0 4.0 0.3 0.0 0.3 2.6 0.3 0.0 238
207 0135 L 31+68 6 Rt 395.69 0.011 0.020 0.05 0.80 2.0 4.0 0.2 0.0 0.2 3.5 0.1 0.0 131 Allowable spread 3.75'
207 0132 L 31+90 32 Lt 394.62 0.011 0.020 0.10 0.88 2.0 4.0 0.3 0.0 0.3 3.0 0.3 0.0 201
207 0130 L 31+05 6 Rt 396.57 0.011 0.030 0.04 0.82 2.0 4.0 0.1 0.0 0.1 2.6 0.1 0.0 135
207 0129 L 31+05 32 Lt 395.21 0.011 0.030 0.08 0.89 2.0 4.0 0.3 0.0 0.3 1.9 0.3 0.0 132
214 0213 L 36+80 30 Rt 382.05 0.005 0.016 0.00 0.50 2.0 4.0 0.0 0.0 0.0 0.5 0.0 0.0 240
214 0212 L 36+80 5 Rt 381.76 0.005 0.016 0.01 0.76 2.0 4.0 0.0 0.0 0.0 2.9 0.0 0.0 240
214 0224 L 38+18 30 Rt 382.42 0.022 0.015 0.07 0.68 2.0 4.0 0.2 0.0 0.2 1.8 0.2 0.0 240
214 0211 L 36+80 31 Lt 381.94 0.005 0.006 0.04 0.89 2.0 4.0 0.1 0.0 0.1 1.9 0.1 0.0 239
214 0221 L 36+61 4 Rt 381.92 0.009 0.020 0.01 0.75 2.0 4.0 0.0 0.0 0.0 I 2.0 0.0 0.0 212
Page 2 of 4 Printed 11/3/2020

CREATE DATE: 7/7/2020 INLET COMPUTATION SHEET
REV. DATE:
I.D. NO.: Davis Park East Pod B PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION ROADWAY RUNOFF INLET
W i- o z w
a w Ti-- w w
g IX Et z z H O O O 15 LL. LL E -J reQ 0 > a w O
w DW W O W 1 W J Q a � Q s Q CO Q ❑ U Cn co
0
� CO M co a ❑ � z O w .=_ _ ❑ a r . Q � � REMARKS
co U2 z ~ LL. E > g § ' <n Qw zw Luz z O m 0Eg � O rx wR a aw
>- Et ❑ 0 I- a 0 W O <n a � � O � O Z cn ¢ O � a HQ } �
O FZ J co 0 W w O 0Q D! 8 HU ❑ 2 ❑ U H ❑ s. co - z2 M. COZ
u, < ❑ cc
0 D.A. C Tc I QD.A. Qc Q Q+Qc Ql(mx) QB
214 0240 L 37+12 5 Rt 381.66 SAG 0.009 0.11 0.76 2.0 4.0 0.3 0.0 0.3 10.9 N/A N/A Spread as low as possible
214 0233 L 39+00 32 Rt 384.02 0.022 0.020 0.18 0.81 2.0 4.0 0.6 0.0 0.6 3.4 0.6 0.0 224
214 0210 L 36+80 57 Lt 379.20 0.005 0.330 0.08 0.49 2.0 4.0 0.2 0.0 0.2 1.6 0.2 0.0
214 0217 L 36+00 31 Lt 383.17 0.021 0.019 0.08 0.89 2.0 4.0 0.3 0.0 0.3 2.0 0.3 0.0 211
214 0239 L 37+12 31 Lt 381.94 SAG 0.002 0.02 0.89 2.0 4.0 0.1 0.0 0.1 0.9 N/A N/A
214 0220 L 36+61 5 Lt 382.05 0.009 0.029 0.04 0.80 2.0 4.0 0.1 0.1 0.2 3.0 0.2 0.0 215
214 0241 L 36+50 4 Rt 382.04 0.011 0.022 0.06 0.75 2.0 4.0 0.2 0.0 0.2 3.7 0.2 0.0 221 Allowable spread 3.75'
214 0215 L 37+12 5 Lt 381.85 SAG 0.032 0.08 0.86 2.0 4.0 0.3 0.1 0.4 3.2 N/A N/A
214 0234 L 40+65 32 Rt 387.31 0.009 0.020 0.03 0.84 2.0 4.0 0.1 0.0 0.1 1.6 0.1 0.0 233
214 0209 L 36+30 52 Lt 382.45 0.015 0.330 0.20 0.53 2.0 1.3 0.1 0.0 0.1
214 0222 L 37+50 31 Lt 382.11 0.009 0.010 0.00 0.90 2.0 4.0 0.0 0.0 0.0 0.5 0.0 0.0 239
214 0218 L 35+75 5 Rt 383.49 0.026 0.022 0.11 0.80 2.0 4.0 0.3 0.0 0.3 3.7 0.3 0.0 241 Allowable spread 3.75'
214 0216 L 37+50 5 Lt 381.94 0.009 0.010 0.11 0.83 2.0 4.0 0.4 0.0 0.4 8.0 0.3 0.1 215 Spread as low as possible
214 0235 L 41+36 34 Rt 387.80 0.003 0.018 0.03 0.90 2.0 4.0 0.1 0.1 0.2 3.1 0.2 0.0
214 0223 L 37+50 61 Lt 383.49 0.000 0.010 23.44 0.75 15.0 0.0 0.1 0.0 0.1
214 0225 L 38+70 31 Lt 383.62 0.022 0.017 0.12 0.82 2.0 4.0 0.4 0.1 0.5 3.2 0.4 0.0 216
214 0219 L 35+75 5 Lt 383.51 0.026 0.017 0.06 0.83 2.0 4.0 0.2 0.1 0.3 4.4 0.3 0.1 220
214 0236 L 41+76 32 Rt 388.31 0.003 0.020 0.18 0.90 2.0 4.0 0.6 0.0 0.6 6.5 0.6 0.1 235 Exist CB,Turn Lane
214 0226 L 38+70 46 Lt 384.25 0.022 0.330 0.17 0.50 2.0 1.5 0.1 0.0 0.1
214 0227 L 39+95 34 Lt 386.07 0.022 0.020 0.24 0.78 2.0 4.0 0.7 0.0 0.8 4.2 0.7 0.1 225
214 0237 L 41+76 44 Rt 386.17 0.003 0.330 0.10 0.90 2.0 4.0 0.3 0.0 0.3 2.4 0.3 0.0
214 0228 L 41+50 35 Lt 387.59 0.003 0.020 0.14 0.82 2.0 4.0 0.5 0.0 0.5 5.5 0.4 0.0 227
Page 3 of 4 Printed 11/3/2020

CREATE DATE: 7/7/2020 INLET COMPUTATION SHEET
REV. DATE:
I.D. NO.: Davis Park East Pod B PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION ROADWAY RUNOFF INLET
w H z
o z Lu
d w d ^c J w K wH.J Lz� r . -
ww OHIYEt z z H O O 0 t u_ u_ € J CE 0 > ❑ 1 )g DLu w O ww � M u a wr uj - Q LL O Q QQ❑ aO J Q Q U U U")
REMARKS
U _ > n Qw zw wZ _ _ 6 � = ° - a awco 2z 1- LL
>- ce ❑ 0 0 w
0) 1 z Jco 0 OO 0Q O O Z ❑ L c ¢ O2f an zQ co. f ZJ
< w❑ w ceU D.A. C Tc I Q .A. QC Q Q+QC Ql(mx) QB
r 1 i I i
214 0229 L 42+75 35 Lt 387.97 0.003 0.020 0.07 0.89 2.0 4.0 0.2 0.0 0.3 3.9 0.3 0.0 228
214 0230 L 42+75 51 Lt 388.40 0.003 0.330 0.53 0.40 2.0 4.0 0.8 0.0 0.8 3.3 0.8 0.0
214 0231 L 43+48 35 Lt 388.26 0.003 0.020 0.05 0.83 2.0 4.0 0.2 0.0 0.2 4.6 0.2 0.0 229
214 0232 L 43+99 71 Lt 390.14 0.013 0.020 0.01 0.84 2.0 4.0 0.0 0.4 0.5 3.6 0.4 0.0 231
214 0242 L 44+01 83 Lt 390.26 0.013 0.020 0.48 0.90 2.0 4.0 1.7 0.0 1.7 7.4 1.3 0.4 232 Turn Lane
Page 4 of 4 Printed 11/3/2020

CREATE DATE: 7/7/2020 STORM DRAIN DESIGN COMPUTATIONS
REV. DATE:
I.D. NO.: avis Park East Pod PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION RUNOFF PIPE DESIGN
STRUCTURE = TIME OF fn U W W o ^ J _ J , g x o
c( Q CONCENTRATION z = J W W Q Q Z Q Q
w z NUMBER o 2 g X z (min) W 0 Z_ w O c _ w z 6 Q ACC w m REMARKS
Z z I- '_ co N w O W W C w U 2' J
co J 0 co w Z ? oz d Dd Q H ww J H0 W W
>- o _. J 9 20 o < 1 Ww w cn J w
� v W F- u, TOP, TOP, � z_ ccnn 2 u) a = O
FROM TO CA d 0 w I 0 x = W
d Z -i a INV INV W w > 00
101 102 0102 0101 0.22 0.09 82 2 2 10 5.8 0.5 374.00 0.00 0.021 15 C 9.0 4.3 3.25 371.13
370.75 369.00
106 105 0105 0106 0.27 0.23 15 2 5 10 5.8 1.3 370.31 0.00 0.004 15 C 4.2 3.3 3.00 367.83
367.31 367.25
106 104 0104 0105 0.18 0.16 25 2 5 10 5.8 0.9 372.18 370.31 0.034 15 C 9.0 5.9 3.95 368.74
368.23 367.31
106 103 0103 0104 0.03 0.02 16 2 2 10 5.8 0.1 371.50 372.18 0.005 15 C 5.0 0.3 3.17 368.74
368.33 368.23
110 109 0109 0110 1.88 1.25 37 2 29 29 3.6 4.4 375.08 0.00 0.123 0.016 15 S 9.0 9.2 3.00 373.24
372.08 367.27
110 108 0108 0109 0.80 0.41 30 2 8 10 5.8 2.4 376.25 375.08 0.036 15 C 9.0 7.8 3.00 373.92
373.25 372.08
110 114 0114 0109 0.94 0.73 157 2 28 28 3.7 2.7 380.66 375.08 0.035 15 C 9.0 8.4 3.00 378.53
377.66 372.08
110 107 0107 0108 0.58 0.23 49 2 7 10 5.8 1.3 376.75 376.25 0.025 15 C 9.0 6.0 2.25 375.10
374.50 373.25
110 113 0113 0114 0.47 0.39 36 2 6 10 5.8 2.3 381.92 380.66 0.033 15 C 9.0 7.5 3.00 379.70
378.92 377.66
110 119 0119 0114 0.27 0.19 229 2 22 22 4.2 0.8 391.31 380.66 0.046 15 C 9.0 6.5 3.00 388.74
388.31 377.66
110 111 0111 0107 0.48 0.18 106 2 5 10 5.8 1.1 381.10 376.75 0.040 15 C 9.0 6.7 2.25 379.29
378.85 374.50
110 115 0115 0113 0.41 0.34 47 2 5 10 5.8 2.0 383.69 381.92 0.035 15 C 9.0 7.6 3.00 381.29
380.69 378.92
110 120 0120 0119 0.06 0.02 15 2 2 10 5.8 0.1 390.05 391.31 0.029 15 C 9.0 3.0 1.25 388.98
388.80 388.31
110 121 0121 0119 0.16 0.13 50 2 20 20 4.4 0.6 393.98 391.31 0.050 15 C 9.0 6.1 3.00 391.38
390.98 388.31
110 112 0112 0111 0.38 0.13 104 2 2 10 5.8 0.7 384.25 381.10 0.007 15 C 5.7 3.2 4.70 380.01
379.55 378.85
110 116 0116 0115 0.24 0.21 152 2 3 10 5.8 1.2 390.35 383.69 0.041 15 C 9.0 7.1 3.37 387.53
386.98 380.69
Page 1 of 5 Printed 11/3/2020

CREATE DATE: 7/7/2020 STORM DRAIN DESIGN COMPUTATIONS
REV. DATE:
I.D. NO.: avis Park East Pod PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION RUNOFF PIPE DESIGN
STRUCTURE = TIME OF fn U W W o ^ J _1 J g x o
c( Q CONCENTRATION Z = J W W Q Q Z Q Q
w NUMBER o 2 g X z (min) w t 0 Z_ Ej 6 d w z ° Q w w m REMARKS
z z HL co y W Ow W 2w U w
J 0 ln0 w Z ? 5g d Da Q H W W J I- I W W
>- D _. J O g0 ° Q � Wr cn J w
o w F- C TOP, TOP, � z_ ccnn 2 u) a = O c7 CC
FROM TO CA a O w I Q X = a
I z o INV INV W w > 00
110 122 0122 0121 0.05 0.04 34 2 17 17 4.7 0.2 394.67 393.98 0.014 15 C 8.4 2.9 3.17 391.72
391.50 390.98
110 117 0117 0116 0.24 0.21 22 2 2 10 5.8 1.2 390.11 390.35 0.005 15 C 5.2 3.4 3.00 387.67
387.11 386.98
110 123 0123 0122 0.03 0.03 116 2 2 10 5.8 0.2 398.80 394.67 0.035 15 C 9.0 3.7 3.17 395.84
395.63 391.50
110 118 ®®® 0.20
20 Una)
®® 391.05 ®
:: 387.117 0 .®O.® 6.6
', ®I
128 127 0127 0128 0.72 0.42 28 4 10 5.8 2.4 392.63 0.00 0.011 18 C 11.9 5.1 1.50 391.72
391.13 390.83
397.18 392.63
128 133 0133 0127 0.72 0.42 18 2 4 10 5.8 2.4 391.31 391.13 0.010 18 C E 11.1 4.8 5.87 392.03
128 125 0125 0133 0.60 0.31 42 2 3 10 5.8 1.8 395.66 397.18 0.012 18 C E 12.5 5.0 3.82 392.51
391.84 391.31
128 134 0134 0133 0.11 0.09 20 2 2 10 5.8 0.5 397.43 397.18 0.011 15 C 7.3 3.4 3.17 394.64
394.26 394.01
128 124 0124 0125 0.15 0.14 40 2 2 10 5.8 0.8 396.00 395.66 0.011 15 C 7.4 3.9 3.00 393.47
393.00 392.52
128 126 0126 0125 0.38 0.12 22 2 2 10 5.8 0.7 393.50 395.66 0.007 18 C 9.4 0.9 1.50 392.54
392.00 391.84 _
207 206 0206 0207 • 1.16 0.76 9 2 16 16 4.8 3.7 388.15 0.00 0.007 15 C 6.0 5.0 3.07 386.13
385.08 385.00
207 205 0205 0206 0.56 0.45 39 2 15 15 4.9 2.2 389.70 388.15 0.037 15 C 9.0 7.8 2.99 387.31
386.71 385.15
207 238 0238 0206 0.57 0.29 34 2 3 10 5.8 1.7 388.25 388.15 0.005 15 C E 4.7 1.5 3.00 386.16
385.25 385.08
207 204 0204 0205 0.51 0.41 51 2 15 15 4.9 2.0 391.72 389.70 0.037 15 C 9.0 7.8 3.00 389.46
388.72 386.71
207 208 0208 0238 0.39 0.15 59 2 I 2 10 5.8 0.9 387.07 388.25 0.005 15 C E 5.1 0.9 1.50 386.19
385.57 385.25
207 203 0203 0204 10.38 0.32 36 2 14 14 5.2 1.6 392.46 391.72 0.019 15 C 9.0 5.8 3.00 390.10
389.46 388.72
Page 2 of 5 Printed 11/3/2020

CREATE DATE: 7/7/2020 STORM DRAIN DESIGN COMPUTATIONS
REV. DATE:
I.D. NO.: avis Park East Pod PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION RUNOFF PIPE DESIGN
STRUCTURE = TIME OF fn U W W b ^ J � J g � o
c( Q CONCENTRATION Z = J W W WW Q < Z QI Q
w NUMBER o g X (min) W 0 Z_ _, - w z ¢ w w m REMARKS
H Z z I- t w W O w W 2 W U J
co J 0 coo w Z ? 5g a Da Q H ww J I- 0 W W
>- DS J O g0 0 Q I- Wa W (n J W
co 0 W F- U) TOP, TOP, � z_ ccnn 2 u) � a = O0 CC
FROM TO CA a n O w I Q X = W
d z a INV INV W w > 00
207 202 0202 0203 0.38 0.32 66 2 14 14 5.2 1.6 393.93 392.46 0.016 15 C 8.8 5.5 3.37 391.22
390.56 389.46
207 131 0131 0202 0.11 0.09 87 2 10 10 5.8 0.5 395.45 393.93 0.017 15 C 9.0 4.0 3.00 392.74
392.45 390.93
207 201 0201 0202 0.27' 0.23 22 2 8 10 5.8 1.3 393.70 393.93 0.006 15 C 5.3 2.0 3.00 391.31
390.70 390.56
207 135 0135 0131 0.09 0.07 22 2 9 10 5.8 0.4 395.69 395.45 0.009 15 C 6.8 3.1 3.00 392.96
392.69 392.45
207 132 0132 0201 0.17 0.15 86 2 6 10 5.8 0.9 394.62 393.70 0.010 15 C 7.1 3.9 3.00 392.02
391.62 390.70
207 130 0130 0135 0.04 0.03 60 2 2 10 5.8 0.2 396.57 395.69 0.011 15 C 7.4 2.6 3.17 393.63
393.40 392.69
207 129 0129 0132 0.08 0.07 81 2 2 10 5.8 0.4 395.21 394.62 0.007 15 C 5.9 2.7 3.00 392.54
392.21 391.62
214 213 0213 0214 26.87 20.00 23 2 15 15 4.9 97.3 382.05 0.00 0.017 0.004 48 C 120.0 11.9 7.49 377.65
374.56 374.15
214 212 0212 0213 26.28 19.50 22 2 15 15 4.9 95.0 381.76 382.05 0.014 0.004 48 C 120.0 11.5 6.86 377.95
374.90 374.56
214 224 0224 0213 0.59 0.50 138 2 7 10 5.8 2.9 382.42 382.05 0.005 15 C 4.9 4.2 3.00 380.13
379.42 378.73
214 211 0211 0212 25.68 19.02 33 2 15 15 4.9 92.8 381.94 381.76 0.013 0.004 48 C 120.0 11.6 6.59 379.25
375.35 374.90
214 221 0221 0212 0.29 0.23 16 2 5 10 5.8 1.3 381.92 381.76 0.008 15 C 6.4 4.0 3.00 379.45
378.92 378.76
214 240 0240 0212 0.31 0.25 29 2 4 10 5.8 1.4 381.66 381.76 0.005 15 C 4.9 3.5 2.95 379.34
378.71 378.55
214 233 0233 0224 0.52 0.45 79 2 6 10 5.8 2.6 384.02 382.42 0.020 15 C 9.0 6.7 3.00 381.71
381.02 379.42
214 210 0210 0211 0.28 0.15 25 2 4 10 5.8 0.8 379.20 381.94 0.000 15 C 1.3 0.7 2.25 379.26 X 15"OEP
376.95 376.94
214 217 0217 0211 0.08 0.07 76 2 2 10 5.8 0.4 383.17 381.94 0.016 15 C 8.7 3.7 3.00 380.52
380.17 378.94
Page 3 of 5 Printed 11/3/2020

CREATE DATE: 7/7/2020 STORM DRAIN DESIGN COMPUTATIONS
REV. DATE:
I.D. NO.: avis Park East Pod PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION RUNOFF PIPE DESIGN
STRUCTURE = TIME OF fn U W W O ^ J _ J , g � x o
c( Q CONCENTRATION z i J W W Q Q Z QI Q
w z NUMBER o 2 g X z (min) W co -0 z_ LU 0 c _ w z 6 Q ACC w m REMARKS
Z z ~ L N w O W W C w U a' J
co J 0 coo w Z ? 5g a Da Q H ww J H0 W W
D �. J 9 gO ° Q I- Wa W (n J w
v w F- u) TOP, TOP, � z_ ccnn 2 u) Cl) a = O C7 CC
FROM TO CA a 0 w I Q x I w
d z ❑ INV INV W w > 00
214 239 0239 0211 25.27 18.76 29 2 15 15 4.9 91.8 381.94 381.94 0.014 0.003 48 C 120.0 7.4 6.13 379.15
375.81 375.35
214 220 0220 0221 0.04 0.04 8 2 2 10 5.8 0.2 382.05 381.92 0.012 15 C 7.6 0.4 3.00 379.45
379.05 378.92
214 241 0241 0221 0.23 0.19 8 2 5 10 5.8 1.1 382.04 381.92 0.009 15 C 6.8 3.9 3.02 379.45
379.02 378.92
214 215 0215 0240 0.19 0.16 8 2 3 10 5.8 0.9 381.85 381.66 0.004 15 C 4.2 1.5 3.10 379.38
378.75 378.71
214 234 0234 0233 0.34 0.30 162 2 4 10 5.8 1.8 387.31 384.02 0.014 15 C 8.2 5.3 4.05 383.81
383.26 381.02
214 209 0209 0210 0.20 0.10 48 2 2 10 5.8 0.6 382.45 379.20 0.086 15 C 9.0 7.4 1.25 381.61
381.20 376.95
214 222 0222 0239 25.25 18.74 35 2 15 15 4.9 91.7 382.11 381.94 0.014 0.003 48 C 120.0 11.9 5.75 380.25
376.36 375.81
214 218 0218 0241 0.17 0.14 72 2 3 10 5.8 0.8 383.49 382.04 0.020 15 C 9.0 4.8 2.98 380.98
380.51 379.02
214 216 0216 0215 0.11 0.10 35 2 2 10 5.8 0.6 381.94 381.85 0.005 15 C 4.9 0.9 3.00 379.41
378.94 378.75
214 235 0235 0234 0.31 0.28 68 2 3 10 5.8 1.6 387.80 387.31 0.006 15 C E 5.6 3.9 4.09 384.23
383.71 383.26
214 223 0223 0222 23.44 17.50 30 15 15 15 4.9 85.8 383.49 382.11 0.033 0.003 48 C 120.0 13.5 6.08 381.97
377.41 376.36
214 225 0225 0222 1.81 1.24 117 2 5 10 5.8 7.2 383.62 382.11 0.013 0.010 15 C 7.8 7.2 3.00 381.94
380.62 379.11
214 219 0219 0218 0.06 0.05 8 2 2 10 5.8 0.3 383.51 383.49 0.004 15 C 4.2 0.7 2.96 380.99
380.55 380.51
214 236 0236 0235 0.28 0.25 37 2 3 10 5.8 1.4 388.31 387.80 0.009 15 C E 6.8 4.4 4.10 384.85
384.21 383.83
214 226 0226 0225 0.17 0.09 14 2 I 2 10 5.8 0.5 384.25 383.62 0.149 15 S 9.0 5.2 1.25 383.39
383.00 380.62
214 227 0227 0225 1.52 1.05 122 2 4 10 5.8 6.1 386.07 383.62 0.020 0.008 15 C 9.0 8.4 3.00 384.12
383.07 380.62
Page 4 of 5 Printed 11/3/2020

CREATE DATE: 7/7/2020 STORM DRAIN DESIGN COMPUTATIONS
REV. DATE:
I.D. NO.: avis Park East Pod PROJ. NO.: 13276001 COUNTY: Durham DESIGNED BY: KLF
DESCRIPTION: REVD BY: VWB
LOCATION RUNOFF PIPE DESIGN
STRUCTURE = TIME OF U W W b ^ J _1 J - g � x o
c( ^ <r I CONCENTRATION Cl)Z i W W W WW Q Q Z Q Q
W Y NUMBER o g X cp (min) w U Z_ 8 d w z ° < - w w o REMARKS
z o z I- L � N w OW W � w U w
J lnU w Z ? og d Dd Q H W w J I- I W W
co>- Dom. J O go o Q I- Wr W (n J W
� v W F u, TOP, TOP, � z_ ccnn 2 co a O C7 cc
FROM TO CA d J 0 w I Q xI W
d Z a INV INV W J CO> 00
214 237 0237 0236 0.10 0.09 10 2 2 10 5.8 0.5 386.17 388.31 0.020 15 C E ' 9.0 4.1 1.45 385.09
384.72 384.46
214 228 0228 0227 1.28 0.87 152 2 4 10 5.8 5.0 387.59 386.07 0.008 0.005 15 C 6.3 5.7 3.25 385.29
384.34 383.07
214 229 0229 0228 1.14 0.75 123 2 3 10 5.8 4.4 387.97 387.59 0.005 0.004 15 C 5.0 4.4 3.00 386.12
384.97 384.34
214 230 0230 0229 0.53 0.21 14 2 2 10 5.8 1.2 388.40 387.97 0.069 15 C 9.0 7.8 2.25 386.75
386.15 384.97
214 231 0231 0229 0.54 0.48 70 2 3 10 5.8 2.8 388.26 387.97 0.004 15 C 4.4 2.4 3.00 386.25
385.26 384.97
214 232 0232 0231 0.49 0.44 62 2 2 10 5.8 2.6 390.14 388.26 0.029 15 C 9.0 7.6 2.99 387.92
387.15 385.26
214 242 0242 0232 0.48 0.43 9 2 2 10 5.8 2.5 390.26 390.14 0.009 15 C 6.6 4.8 3.00 388.20
387.26 387.15
Page 5 of 5 Printed 11/3/2020

Ditch Calculations
We have evaluated the proposed discharge points in both the pre and post construction
scenarios to determine the increase, if any, in flow rate offsite. In addition, the outfall
ditches were designed to contain the 10-year event within their respective banks.
Temporary and permanent ditch linings have been designed to meet North Carolina
Department of Transportation design standards.

Date: 4/15/2020 Kimley-Horn & Associates, Inc.
Raleigh, NC
Project Number: 12329063 Designed By: DLH
County: WAKE Checked By:
Ditch Computation Sheet
Description: Holly Springs Road Ph2
Ditch Location D.A. C Q10 Slope Base Side Depth Velocity Remarks Liner Type
From To L/M/R (acres) (cfs) (ft/ft) Width Slopes (ft) (fps)
20+50-L- 21+85-L- LT 0.07 0.30 0.12 0.020 0 4:1/3:1 0.17 1.14
21+85-L- 22+60-L- LT 0.11 0.47 0.29 0.043 0 4:1/3:1 0.21 1.91
35+80-L- 36+30-L- LT 0.20 0.53 0.61 0.030 2 4:1/3:1 0.21 1.06
38+70-L- 39+75-L- LT 0.17 0.50 0.50 0.019 0 4:1/3:1 0.30 1.60
Page 1 of 1

Cross Pipe Data Sheet
The following pipe data sheet shows the calculations for the proposed pipe from structure
223 to structure 214.

PIPE DATA SHEET
Date 07/09/200 Sheet 1 of 1
Project No. 013276001 I.D. No. Davis Park East County Durham Designed By KLF Checked By
Shoulder CL Elev. 382.06 PLAN SUMMARY DATA
Elev 383.06 Drainage Area 23.44 ac
Design Freq. 25 yr
Station 36+80 Design Disch. 95.00 cfs
Skew 90.0 ° A
A H Design H.W. Elev. 381.96 ft
v
Size/Type Pipe 48" H.W. A T.W. Q100 Disch. 107.00 cfs
Type Entrance Grooved End w/HW LSo v Q100 H.W. Elev. 382.43 ft
Direction of Flow Lt to Rt T Overtopping Freq. >100yr yr
Hydrological Method Rational Inv. Elev. 377.41 So = 1.71 % Inv. Elev. 374.15 Overtopping Disch. 113.80 cfs
HW Control Elev 382.87 L = 190.40 S Overtopping Elev. 382.73 ft
INLET CONTROL OUTLET CONTROL
Size &Type Pipe Freq Q Nat. Allow. T.W. HW/D H.W. Ke do dc+d ho H LSo H.W. H.W. Vo COMMENTS
(Yrs.) (cfs) H.W H.W. 2 Elev. (ft/s)
48" RCP 10 86.00 2.48 1.06 4.22 0.2 2.85 3.42 3.42 1.45 3.26 1.00 381.63 14.59 Inlet Control
48" RCP 25 95.00 2.67 1.14 4.55 0.2 3.02 3.51 3.51 1.77 3.26 1.47 381.96 14.92 Inlet Control
48" RCP 50 100.00 2.77 1.19 4.74 0.2 3.11 3.56 3.56 1.96 3.26 2.22 382.15 15.11 Inlet Control
48" RCP 100 107.00 2.92 1.26 5.02 0.2 3.24 3.62 3.62 2.25 3.26 2.55 382.43 15.46 Inlet Control
SUMMARY AND RECOMMENDATIONS : Proposed 48"RCP with HW at entrance.Average slope from HW to outlet used for analysis.
Water will breach shoulder at 37+00-L-LT=382.87'.
This yields 0.91'of freeboard during the 25 yr storm.

Outfall Analysis
The following Post Construction Discharge Q 10 Outfall Channel Analysis sheet shows
the pre and post outfall calculations.

Kimley>>>Horn
2 Year Analysis
Pre-vs Post-Construction Discharges
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: Date:
Revised by: Date:
EXISTING CONDITIONS I I PROPOSED CONDITIONS
DRAINAGE RUNOFF Time of Storm Q DRAINAGE RUNOFF Time of Storm Q DISCHARGE DISCHARGE
AREA COEFF. Concentration Intensity TOTAL AREA COEFF. Concentration Intensity TOTAL DIFF. INCREASE
Station/Structure# A(acres) C Tc(min) I(in/hr) Clio(cfs) Station/Structure# A(acres) C Tc(min) I(in/hr) Qio(cfs) (CFS) VA)
19+71-L-LT/0101 0.38 0.41 10.00 4.50 0.70 19+71-L-LT/0101 0.22 0.41 10.00 4.50 0.40 -0.30 -42.73
20+68-L-RT/0106 0.09 0.90 10.00 4.50 0.37 20+68-L-RT/0106 0.27 0.86 10.00 4.50 1.02 0.65 175.17
21+65-L-RT/0110 3.93 0.51 10.00 4.50 8.98 21+65-L-RT/0110 3.95 0.51 10.00 4.50 9.05 0.08 0.87
30+53-L-RT/0128 0.55 0.57 10.00 4.50 1.40 30+53-L-RT/0128 0.73 0.88 10.00 4.50 2.88 1.48 105.89
34+42-L-RT/0207 0.76 0.53 10.00 4.50 1.80 34+42-L-RT/0207 _ 1.16 0.90 10.00 4.50 4.71 2.90 160.92
36+80-L-RT/0214 25.70 0.73 15.00 3.80 71.00 36+80-L-RT/0214 26.80 0.74 15.00 3.80 75.75 4.75 6.69
Page 1 of 6

Kimley>>>Horn
Post-Construction Discharge
Q2 Outfall Channel Analysis
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: VWB Date: 7/14/2020
Revised by: Date:
Outlet T DA C Tc i2 Q2 s Fore Slope Backslope Base Width Ditch Existing Design Depth y V Manning's
(ac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.38 0.41 10.00 4.50 0.70 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.13 1.59 0.035
Pre 20+88-L-RT/0106 0.09 0.90 10.00 4.50 0.37 0.200 20:1 20:1 0.00 Triangular N/A Leave as is 0.09 2.37 0.035
Downstream 21+65-L-RT/0110 3.93 0.51 10.00 4.50 8.98 0.060 20:1 20:1 0.00 Triangular N/A Leave as is 0.37 3.35 0.035
Outfalls 30+53-L-RT/0128 0.55 0.57 10.00 4.50 1.40 0.010 10:1 10:1 0.00 Triangular N/A Leave as is 0.33 1.28 0.035
34+42-L-RT/0207 0.76 0.53 10.00 4.50 1.80 0.025 3:1 3:1 5.00 Base 2.0000 Leave as is 0.17 1.93 0.035
36+80-L-RT/0214 25.70 0.73 15.00 3.80 71.00 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is. 2.89 3.11 0.069
Outlet DA C Tc i2 Q2 s Fore Slope Backslope Base Width Ditch Existing Design Depth y v Manning's
lac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.22 0.41 10.00 4.50 0.40 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.14 0.84 0.069
Post 20+68-L-RT/0106 0.27 0.86 10.00 4.50 1.02 0.200 20:1 20:1 0.00 Triangular N/A Leave as is 0.17 1.83 0.069
Downstream 21+65-L-RT/0110 3.95 0.51 10.00 4.50 9.05 0.060 20:1 20:1 0.00 Triangular N/A Leave as is 0.47 2.02 0.069
Outfalls 30+53-L-RT/0128 _ 0.73 _ 0.88 10.00 4.50 _ 2.88 0.010 10:1 10:1 0.00 _ Triangular _ N/A _ Leave as is _ 0.56 _ 0.92 _ 0.035
34+42-L-RT/0207 1.16 0.90 10.00 4.50 4.71 0.025 3:1 3:1 5.00 Base 2.0000 Leave as is 0.44 1.71 0.069
36+80-L-RT/0214 26.80 0.74 15.00 3.80 75.75 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is 3.07 3.06 0.072
Downstream Outlet Depth Velocity
Outfalls Change(ft) Change(fps)
19+71-L-LT/0101 0.01 -0.75
20+68-L-RT/0106 0.08 -0.54
30+53-L-RT/0128 0.23 -0.36
34+42-L-RT/0207 0.27 -0.22
36+80-L-RT/0214 0.18 -0.05
Page 2 of 6

Kimley>>>Horn
5 Year Analysis
Pre-vs Post-Construction Discharges
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: VWB _ Date: 7/14/2020
Revised by: Date:
EXISTING CONDITIONS I I PROPOSED CONDITIONS
DRAINAGE RUNOFF Time of Storm Q DRAINAGE RUNOFF Time of Storm Q DISCHARGE DISCHARGE
AREA COEFF. Concentration Intensity TOTAL AREA COEFF. Concentration Intensity TOTAL DIFF. INCREASE
Station/Structure# A(acres) C Tc(min) I(in/hr) Clio(cfs) Station/Structure# A(acres) C Tc(min) I(in/hr) Qio(cfs) (CFS) (%)
19+71-L-LT/0101 0.38 0.41 10.00 5.20 0.80 19+71-L-LT/0101 0.22 0.41 10.00 5.20 0.46 -0.34 -42.73
20+68-L-RT/0106 0.09 0.90 10.00 5.20 0.43 20+68-L-RT/0106 0.27 0.86 10.00 5.20 1.18 0.75 175.17
21+65-L-RT/0110 3.93 0.51 10.00 5.20 10.37 21+65-L-RT/0110 3.95 0.51 10.00 5.20 10.46 0.09 0.87
30+53-L-RT/0128 0.55 0.57 10.00 5.20 1.62 30+53-L-RT/0128 0.73 0.88 10.00 5.20 3.33 1.71 105.89
34+42-L-RT/0207 0.76 0.53 10.00 5.20 2.08 34+42-L-RT/0207 _ 1.16 0.90 10.00 5.20 5.44 3.35 160.92
36+80-L-RT/0214 25.70 0.73 15.00 4.40 82.22 36+80-L-RT/0214 26.80 0.74 15.00 4.40 87.72 5.50 6.69
Page 3 of 6

Kimley>>>Horn
Post-Construction Discharge
Q5 Outfall Channel Analysis
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: VWB Date: 7/14/2020
Revised by: Date:
Outlet T DA C Tc i5 Q5 s Fore Slope Backslope Base Width Ditch Existing Design Depth y V Manning's
r (ac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.38 0.41 10.00 5.20 0.80 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.14 1.67 0.035
Pre 20+68-L-RT/0106 0.09 0.90 10.00 _ 5.20 0.43 0.200 20:1 20:1 _ 0.00 Triangular N/A Leave as is 0.09 2.47 0.035
Downstream 21+65-L-RT/0110 3.93 0.51 10.00 5.20 10.37 0.060 20:1 20:1 0.00 Triangular N/A Leave as is 0.39 3.47 0.035
• •
Outfalls 30+53-L-RT/0128 0.55 0.57 10.00 5.20 1.62 0.010 10:1 10:1 0.00 _ Triangular N/A Leave as is 0.35 1.32 0.035
34+42-L-RT/0207 0.76 0.53 10.00 5.20 2.08 0.025 3:1 3:1 5.00 Base 2.0000 Leave as is _ 0.18 _ 2.03 0.035
36+80-L-RT/0214 25.70 0.73 15.00 4.40 82.22 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is 3.13 3.23 0.069
DA C Tc i5 Q5 s Fore Slope Backslope Base Width Ditch Existing Design Depth y V Manning's
(ac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.22 0.41 10.00 5.20 0.46 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.15 0.88 0.069
Post 20+68-L-RT/0106 0.27 0.86 10.00 5.20 1.18 0.200 20:1 20:1 0.00 Triangular N/A Leave as is. 0.18 1.90 0.069
Downstream 21+65-L-RT/0110 3.95 0.51 10.00 5.20 10.46 0.060 20:1 20:1 0.00 Triangular N/A Leave as is _ 0.50 2.09 0.069
Outfalls 30+53-L-RT/0128 0.73 0.88 10.00 5.20 3.33 0.010 10:1 10:1 0.00 Triangular N/A Leave as is 0.59 0.95 0.069
34+42-L-RT/0207 1.16 0.90 10.00 5.20 5.44 0.025 3:1 3:1 5.00 Base 2.0000 Leave as is _ 0.47 1.79 0.069
36+80-L-RT/0214 26.80 0.74 15.00 4.40 87.72 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is 3.31 3.18 0.072
Downstream Outlet Depth Velocity
Outfalls Change(ft) Change(fps)
19+71-L-LT/0101 0.01 -0.79
20+68-L-RT/0106 0.09 -0.57
30+53-L-RT/0128 0.24 -0.37
34+42-L-RT/0207 0.29 -0.24
36+80-L-RT/0214 0.18 -0.05
Page 4 of 6

Kimley>>>Horn
10 Year Analysis
Pre-vs Post-Construction Discharges
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: VWB Date: 7/14/2020
Revised by: Date:
EXISTING CONDITIONS I I PROPOSED CONDITIONS
DRAINAGE RUNOFF Time of Storm Q DRAINAGE RUNOFF Time of Storm Q DISCHARGE DISCHARGE
AREA COEFF. Concentration Intensity TOTAL AREA COEFF. Concentration Intensity TOTAL DIFF. INCREASE
Station/Structure# A(acres) C Tc(min) I(in/hr) Clio(cfs) Station/Structure# A(acres) C Tc(min) I(in/hr) Qio(cfs) (CFS) (%)
19+71-L-LT/0101 0.38 0.41 10.00 5.80 0.90 19+71-L-LT/0101 0.22 0.41 10.00 5.80 0.51 -0.38 -42.73
20+68-L-RT/0106 0.09 0.90 10.00 5.80 0.48 20+68-L-RT/0106 0.27 0.86 10.00 5.80 1.31 0.84 175.17
21+65-L-RT/0110 3.93 0.51 10.00 5.80 11.57 21+65-L-RT/0110 3.95 0.51 10.00 5.80 11.67 0.10 0.87
30+53-L-RT/0128 0.55 0.57 10.00 5.80 1.81 30+53-L-RT/0128 0.73 0.88 10.00 5.80 3.72 _ 1.91 105.89
34+42-L-RT/0207 0.76 0.53 10.00 5.80 2.32 34+42-L-RT/0207 _ 1.16 0.90 10.00 5.80 6.07 3.74 _ 160.92
36+80-L-RT/0214 25.70 0.73 15.00 4.90 91.56 36+80-L-RT/0214 26.80 0.74 15.00 4.90 97.68 6.13 6.69
Page 5of6

Kimley>>>Horn
Post-Construction Discharge
Clio Outfall Channel Analysis
Project Information
Project Name:Davis Park East Pod B
KHA Project#: 013276001
Designed by: KLF Date: 7/13/2020
Checked by: VWB Date: 7/14/2020
Revised by: Date:
Outlet DA C Tc in, 410 s Fore Slope Backslope Base Width Ditch Existing Design Depth y V Manning's
(ac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.38 0.41 10.00 5.80 0.90 _ 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.15 1.73 0.035
Pre 20+68-L-RT/0106 0.09 0.90 10.00 5.80 0.48 0.200 20:1 20:1 0.00 Triangular N/A Leave as is 0.10 2.53 0.035
Downstream 21+65-L-RT/0110 3.93 0.51 10.00 5.80 11.57 0.060 20:1 20:1 0.00 Triangular N/A Leave as is 0.40 3.57 0.035
Outfalls 30+53-L-RT/0128 0.55 0.57 10.00 5.80 1.81 0.010 10:1 10:1 0.00. Triangular N/A Leave as is 0.36 1.36 0.035
34+42-L-RT/0207 0.76 0.53 10.00 _ 5.80 2.32 0.025 3:1 3:1 5.00 Base 2.0000 Leave as is 0.20 2.11 0.035
36+80-L-RT/0214 25.70 0.73 15.00 4.90 91.56 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is 3.31 3.32 0.069
Outlet DA C Tc 110 410 s Fore Slope Backslope Base Width Ditch Existing Design Depth y V Manning's
(ac) Value (min) (in/hr) (cfs) (ft/ft) (ft) Type Depth(ft) of Ditch(ft.) (ft) (fps) n
19+71-L-LT/0101 0.22 0.41 10.00 5.80 0.51 0.025 3:1 3:1 3.00 Base 2.0000 Leave as is 0.16 0.91 0.069
Post 20+68-L-RT/0106 0.27 0.86 10.00 5.80 1.31 0.200 20:1 20:1 0.00 Triangular N/A Leave as is 0.18 1.96 0.069
Downstream 21+65-L-RT/0110 3.95 0.51 10.00 5.80 11.67 0.060 20:1 20:1 0.00 Triangular N/A Leave as is _ 0.52 2.15 0.069
Outfalls 30+53-L-RT/0128 0.73 0.88 10.00 5.80 3.72 0.010 10:1 10:1 0.00 Triangular N/A Leave as is 0.62 0.98 0.069
34+42-L-RT/0207 1.16 0.90 10.00 5.80 6.07 0.025 3:1 3:1 5.00 Base 2.0000 Leave as.is 0.50 1.85 0.069
36+80-L-RT/0214 26.80 0.74 15.00 4.90 97.68 0.010 1:1 1:1 5.00 Base 5.0000 Leave as is 3.51 3.28 0.072
Downstream Outlet Depth Velocity
Change(ft) Change(fps)
Outtalk
19+71-L-LT/0101 0.01 -0.82
20+68-L-RT/0106 0.08 -0.57
30+53-L-RT/0128 0.26 -0.38
34+42-L-RT/0207 0.30 -0.26
36+80-L-RT/0214 0.20 -0.04
Page 6 of 6

Outfall Analysis for Davis Park East Pod B.
Table of Contents
2-yr, 5-yr, 10-yr Pre-vs-Post Condition Flow Analysis
Outfall Analysis Document for 10-yr Storm
Drainage Area Figure and Description of Residential Drainage Issues
Note:
The 2-yr, 5-yr, and 10-yr storms were analyzed for the pre and post condition flows. Only the 10-yr
storm results were reported on the redline drainage plans and in the Outfall Analysis Document. There
were no concerns with the 2-yr and 5-yr storms where the 10-yr storm was not a concern.

OUTFALL ANALYSIS 19+71 -L- (LT) OUTLET 0101
Description:
The proposed outfall at 19+71 -L- (LT)is a 15"RCP that outlets into Class 'B' Rip Rap
and flows into an existing ditch. The proposed system contains a drop inlet that will be piped under the
driveway and discharged to the existing ditch. It flows in this ditch until it ultimately enters an existing
system that continues to the west along Hopson Rd.
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Photo 1: Existing Ditch Upstream of Existing Driveway

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Photo 2: Existing Ditch Downstream of Existing Driveway

Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm.
• The outfall has a 10-yr pre-construction flow of 0.90 cfs. The 10-yr post-construction flow is 0.51
cfs. This yields a 42.73% increase. This decrease was anticipated due to the interception of the
ditch upstream of inlet 0102 by inlets 0107 and 0111,which discharge via outlet 0110 to the same
ultimate outfall. The pre-construction velocity is 1.73 fps and the post-construction velocity is
0.91 fps. This yields a percent decrease of 47.40%. The water surface elevation for the pre-
construction condition is 0.15 ft and 0.16 ft for the post-construction condition. This yields a
percent increase of 6.67%. The changes in velocity and water surface elevation are due to the
decrease in flow and the proposed rip rap pad at the outlet.
• The proposed water surface is contained within the existing swale in the post condition.
• No actions recommended at this time.

OUTFALL ANALYSIS 20+68 -L- (RT) OUTLET 0106
Description:
The proposed outfall at 20+68 -L-(RT)is a 15"RCP that outlets into Class 'B' Rip Rap.
System 0106 and 0110 both ultimately flow into a detention-like channel along Distribution Drive. The
existing pipe outlet was inaccessible due to dense vegetation.
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15"RCP Outfall to
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Photo 1: Proposed Drainage for Outfall 0106

Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm.
• The outfall has a pre-construction flow of 0.48 cfs. The post-construction flow is 1.31 cfs.
This yields a 175.17% decrease,but only a decrease of 0.83 cfs. The pre-construction velocity is
2.53 fps and the post-construction velocity is 1.96 fps. This yields a percent decrease of 22.53%.
The water surface elevation for the pre-construction condition is 0.10 ft and 0.18 ft for the post-
construction condition. This yields a percent increase of 80%. These increases were anticipated
due to intercepting water on the curb to the south of the median.
• The proposed water surface is contained within the existing channel in the post condition.
• No actions recommended at this time.

OUTFALL ANALYSIS 21+65 -L- (RT) OUTLET 0110
Description:
The proposed outfall at 21+65 -L-(RT)is a 15"RCP that outlets into Class `B' Rip Rap
just downstream of where the existing pipe outlets today. System 0106 and 0110 both ultimately flow into
a detention-like channel along Distribution Drive. The existing pipe outlet was inaccessible due to dense
vegetation. In both the pre-and post-conditions, offsite flow from the property just west of Keystone Park
Drive was included as it gets to the ultimate outfall.
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Photo 1: Proposed Drainage for Outfall 0110

Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm.
• The outfall has a pre-construction flow of 11.57 cfs. The post-construction flow is 11.67 cfs.
This yields a 0.87%increase. The pre-construction velocity is 3.57 fps and the post-construction
velocity is 2.15 fps. This yields a percent decrease of 39.78%. The water surface elevation for the
pre-construction condition is 0.40 ft and 0.52 ft for the post-construction condition. This yields a
percent increase of 30.00%. These changes in velocity and water surface elevation are due to
adding a rip rap pad at the outlet.
• The proposed water surface is contained within the existing channel in the post condition.
• No actions recommended at this time.

OUTFALL ANALYSIS 30+53 -L- (RT) OUTLET 0128
Description:
The proposed outfall at 30+53 -L- (RT)outlets from an 18"RC,which will be extended from
existing to discharge into the same channel. The existing pipe outlet was inaccessible due to dense
vegetation.
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Photo 1: Existing Conditions Upstream of Existing Pipe(Struct. 0126)

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18"RCP Outfall to —- — ■ - - - -
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Photo 2: Outlet of System 0128 into Existing Channel
Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm.
• The outfall has a pre-construction flow of 1.81 cfs. The post-construction flow is 3.72 cfs.
This yields a 105.89% increase,but only an additional 1.91 cfs. The pre-construction velocity is
1.36 fps and the post-construction velocity is 0.98 fps.This yields a percent decrease of 27.94%.
The water surface elevation for the pre-construction condition is 0.36 ft and 0.62 ft for the post-
construction condition. This yields a percent increase of 72.22%. The flow increases are due to
the widening and realignment of Hopson Drive east of Keystone Park Drive resulting in a larger
total drainage area as well as more impervious area. The changes in water surface elevation and
velocity are due to the flow increases and the installation of a rip rap pad.
• The proposed water surface is contained within the existing channel in the post condition.
• No actions recommended at this time.

OUTFALL ANALYSIS 34+42 -L- (RT) Outlet 0207
Description:
The outfall at 34+42-L-(RT) is an existing 15"RCP that is outlets into an existing channel south
of Hopson Road just west of the existing railroad bridge. In the proposed condition, the pipe outlets 2'
further from the road due to the proposed widening. The pipe outlet was not accessible due to dense
vegetation.
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Photo 1: Existing Condition Upstream of Outlet Pipe(Struct. 0208)

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Photo 2:Proposed Outlet for System 0207
Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm.
• The outfall has a pre-construction flow of 2.32 cfs. The post-construction flow is 6.07 cfs.
This yields a 160.92%decrease. The pre-construction velocity is 2.11 fps and the post-
construction velocity is 1.85 fps. This yields a percent decrease of 12.32%. The water surface
elevation for the pre-construction condition is 0.20 ft and 0.50 ft for the post-construction
condition. This yields a percent increase of 250%. These increases are a result of the increased
impervious area and total area from the roadway widening.
• The proposed water surface is contained within the existing channel in the post condition.
• No actions recommended at this time.

OUTFALL ANALYSIS 36+80 -L- (RT) Outlet 0214
The outfall at 36+80-L- (RT) is a 48"RCP conveying a jurisdictional stream. In existing, the
jurisdictional stream flows through 3 @ 24"RCP's to an open channel before entering a 48"CMP to
cross Hobson Road, as seen in Photo 1. The existing 48"CMP is in poor condition due to corrosion and
breakage, as seen in Photo 3. The proposed design systemizes the JS and discharges it via a 48"RCP with
a Class I Rip Rap pad to the existing channel.
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Photo 1: Proposed Drainage at Outlet 0214

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Photo 2: Existing Conditions Upstream of 48" Crossing
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Photo 3: Existing Conditions at Outlet of 48" CMP

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Photo 4: Existing Conditions Looking Downstream of 48" CMP Outlet
Analysis:
• There are no expected adverse effects on the downstream receiving water.
• There are no expected downstream inadequacies that would adversely impact the highway.
• There are no expected effects to the adjacent property from the 10-yr storm. The proposed 48"
crossing meets NCDOT standards for the headwater/diameter for the 10- and 25yr storms.
• The outfall has a pre-construction flow of 91.56 cfs. The post-construction flow is 97.68 cfs.
This yields a 6.69%increase. The pre-construction velocity is 3.32 fps and the post-construction
velocity is 3.28 fps. This yields a percent decrease of 1.20%. The water surface elevation for the
pre-construction condition is 3.31 ft and 3.51 ft for the post-construction condition. This yields a
percent increase of 6.04%. These increases are a result of the increased impervious area and total
area from the roadway widening.
• The proposed water surface is contained within the existing channel in the post condition.
• No actions recommended at this time.