20080182 Ver 1_Stormwater Info_20080124

Stormwater Calculations
for
Wa I n ut Street Park
Cary, NC
Prepared By:
/~'~~
MITCHELL ~ WESTENDORF, P.A.
ENGINEERING & SURVEYING
/ 709 Legion Road Suite 20 /
Chapel tlil/, NC 275 / 7
April 10, 2007
Revised August 9, 2007
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Narrative
Walnut Street Park is a small neighborhood park proposed in East Cary. The parcel net
acreage. is 10.82 acres. The site is mostly wooded. Proposed development includes trails,
a playground, bathroom building, paved parking lot and infrastructure improvements.
The Stormwater improvements include extending a concrete culvert under Walnut Street
for the proposed trail. We propose to:add a Bioreteution basin;to manage the Stormwater
runofffrom the parking lot.-This bionvtention basin provides quality and quantity
management. The pre-development runoff from the developed.: area of the park for the 10-
year event storm is 1.50 cfs. The post~evelopment runoff from this area is 6.53 cfs
before detention and i.39 cfs after detention. This routing data'is attached under the
"Chainsaw routing method".
The culvert under Walnut Street was extended so a`trail could cross the stream. The
existing pipe is a 24" RCP. We proposed x'30" RCP because the 24" was slightly
undersized and we wanted to have the correct size installed. The: culvert report is s
included.
The bioretention routing analysis is included for the 10 and 100 year storm events. We
also: included the: pipe sizing procedure for the concrete pipes.

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Nitrogen Control Plan
Commercial / Industrial /Residential Sites with Known Impervious Area
Project Title: A ~ Sri ~ ~~~
Type of Project New [ ]Expansion [ ]l=xempt
Basis for exemp ' n
Part I. Riparian Buffers
Area inGudes riparian buffers? [ ] No ~Q Yes [ ]Exempt
If yes,, [ ] 50 foot ~1 O0 foot
River Basin? J/P~+I~G )~Tleuse [ ]Cape Fear
Basis for exemption -
Show buffers on site plan.
Part 1. Nitrogen Calculations (Method 2, Appendix C):
a.. Site Information
Total area of property incl. R/W _~ r 3 ~ ,4e.
Denuded Area
Impervious Area inG. RMI , p
.Managed open space , AEG
Protected open space
Permanently protected undisturbed open
space (forest, unmown meadow)
Permanently protected managed open spa
(grass,. landscaping, etc.)
mpervious Area ,
b. Pre-~evelooment loading:
Area.
Type of Land Cover (acres)
TN export
TN export coeff. from use
(Ibs/ac/yr) (lbstyr)
ce ~.J~I
TOTAL ~ ~ I
d . 0 oao G .o'f 8
1.20 •3 92
O 21.20 (`
Nitrogen Loading Rate (Ibs/aGyr) = Zi
e. Rost-development loading:
Type of Land Cover
Permanently protected undisturbed open
space (forest, unmown meadow)
Permanently protected managed open space
(grass, landscaping, etc.)
Impervious Area
TOTAL
TN export
Area TN export coeff. from use
(acres) (Ibs/ac/vrf (Ibs/vr)
3 o.so 3.08
~~ ~/ 1.20 ~• ~P
z1.2o . 3
2. (i .
Nitrogen Loading Rate (Ibs/aclyr) _ ~. q
.Proposed BMP(s) ~ t t ~o r1
Nitrogen Load after B Ps =
Nitrogen Load Offset by Payments = ~_
Net change in on-site NLoad = d
y-9G -Z. Y~- 2,5 1 lbs.
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Part III. Control of Peak Stormwater Flow ffor 1 year,~esign storm)
Calculated Pre-development Peak Flow _ ~./~ ~- CFr
Calculated Post-development Peak Flow ~ S, L 3 ~~r
Proposed BMP(s) ort~thhon
Post BMP Peak Flow C
I, the undersigned, certify to the best of my knowledge that the above information is
Supply notes & details showing control of Nitrogen and peak stormwater runoff.
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Bioretention Basin
Routing Calcs
Walnut Street Park
8/9/2007
Basin #1
Contour Area ( } Incremental Accum. Z (ft)
Elevation Volume Volume (S)
476 1512 0 0 0
477 2760 2136 2136 1
478 3680 3220 5356 2
479 5015 4348 9704 3
480 6235 5625 15329 4
b In(SZ/S~)
ICS = SZ
Zb
2
= 1.33
= 2136.0
bioretention Walnut Street

Ct~adrrsaw Routing Method
Project Name: Walnut Street Paris
Project ~: BioreteYt6on Basin #1
Date : 8/8/2007
Operator: WDM
Tipe : 10 Year Storm
Mitr2le11 Westeridorf, PA
1709 Legion Road, Suite 201
Chapel Hip, NC 27517
HYdr'o9mPh~ Weir Box / Bartel
Op = , 8.5 CFS N bameLs = 1.00
Tp = 5.0 minutes Opening H = 0.50 feet
dT = 3.0 minutes Opening L = 1.00 feet
CW = 0.00
~9e-St~9e = Crest Elev. = 0.00 feet
K = 2136.00 Bartel Dia_ = 15.00 inches
b = 1:33 Cd = 0.60
~ = 476.0 feet Bar. Invert = 47200 feet
Initial Water Level : Orifice:
~ = 476.1 feet N = 1.00
D = 200 inches
Computed Rasulls : Cd = 0.60
Normal Sure Area = 1337. SF Invert = 476.00 feet
Max :Surf. Area = 2913. SF
Peak Elev. = 477.09 feet Weir 1:
PeakStage= 1:1 fi9et _ L = 16.00 feet
Peak 0upbw = 1.39 CFS Zar ° 477.00 feet
Volume Stored = 2291.7 ft Cw = 3.00
Weir 2: 0.00
L = 0.00 feet
7a _ 0.00 feet
Cw = 0.00
System Loading and Response
30
0
.
- -Inlbw
25.0 p~~,„

20.0
~
15.0
_
1ao
5.0
o.o
o.o so.o 1ao.a 1so.o 200 .0
Tlma (min)
liars
ndn inflow
cfs storage Sbge Oufllow
cis opening tWl
cis oP~g tO)
cfs Hw Bartel
cis `orb
"cis weir 1
cis weir 2
cis
0.0 0:0 10Q8 47$.1 0.00 0.00 5252 11.01 0.00 0.00 0.00
3.0 4.3 400.8 478.1 ..0.01 0.00 5252 11.01 0.01 0.00 0.00
8.0 5.9 867.5 478.5 : 0.07 0.00 52.54 11.64 . 0.07 0.00 0.00
9. 27 19!8.4 478.9 0.10 0.00 5256 1225 0.10 0.00 0.00
.120 - 19 23925 '.477.1 L39 0.00 5257 1248 0. ] 1 1.28 0.00
15.0 0.6 2388.4 4721 1:21 0.00 5257 12.47 0.10 1.11 0.00
180 0.3 22537 ~ 477. 0.51 0.00 5257 1242 0.10 0.40 0.00
21.0 0.1 ' 2210.1 477.0 0.30 0.00 52.57 1240 0.10 020 0.00-
24.0 0.1 2177.2 477.0 018 0.00 52.57 1238 0.10 0.08 0.00
27. OA .2153:8 477J0 Q.12 0.00 5257 1237 0.10 0.02 0.00
30.0 OA 2135.9 477.0 0.10 0.00 5257 1238 010 0.00 0.00
33.0 0.0 2T 19.9 472:0 0:10 0.00 5257 . 1235 . 0.10 0.00 0.00
36.0 oto 21ozs 477.0 o.to 0.00 5257 123a 0.~0 0:00 o.ao
39.9 00 2085.4 477.0 0.10 0.00 5257 1233 0.10 0.00 0.00
420 0.0 2087;7 477.0 0:10 0.00 5257 12.32 0.10 0.00 0.00
45.0 0.0 2049.9 477.0 0.10 0.00. 5258 1232 0.10 0.00 0.00
48.0 0:0 2032.2 477.0 0.10 0.00 5256 1231 0.10 0.00 0.00
51.0 0.0 2014.5 477.0 0.10 0.00 5256 12.30 0.10 0.00 0.00
54.0 -0:0 199E9 477.0 0.10 0.00 5256 1229 0.10 0.00 0.00
57.0 0.0 1979.3 476.9 0:10 0.00 52.56 12.28 0.10 0.00 0.00
80.0 0:0 1981:8 476.9 0.10 0.00 52.56 1227 0.10 0.00 0.00
63.0 0.0 1944.3 476.9 0.10 0.00 5256 12.26 0.10 0.00 0.00
66.0 0.0 1827.0 478.8 0.10 0.00 52.56 12.25 0.10 0.00 0.00
69.0 0.0 1909.6 476.9 0.10 0.00 5256 12.24 0.10 0.00 0.00
720 0.0 18924 476.9 0.10 0.00 52.56 1224 0.10 0.00 0.00
75.0 0.0 18752 478.9 0.10 0.00 52.58 1223 0.10 0.00 0.00
78.0 0.0 1858.1 476.9 0.09 0.00 5256 12.22 0.09 0.00 0.00
81.0 0.0 1841.0 476.9 0.09 0.00 5256 1221 0.09 0.00 0.00
84.0 0.0 1824.0 476.9 0.09 0.00 52.56 12.20 0.09 0.00 0.00
87.0 0.0 1807.1 476.9 0.09 0.00 52.58 12.19 0.09 0.00 0.00
90.0 0.0 17902 478.9 0.09 0.00 5256 1218 0.09 0.00 0.00
93.0 0.0 1773.4 476.9 0.09 0.00 52.56 12.17 0.09 0.00 0.00
96.0 0.0 1756.7 476.9 0.09 0.00 5256 12.16 0.09 0.00 0.00
99.0 0.0 1740.0 476.9 0.09 0.00 5256 12.15 0.09 0.00 0.00
1020 0.0 1723.4 478.9 0.09 0.00 5256 12.15 0.09 0.00 0.00
105.0 0.0 1708.8 476.8 0.09 0.00 52.56 12.14 0.09 0.00 0.00
108.0 0.0 1890.4 478.8 0.09 0.00 5256 1213 0.09 0.00 0.00
111.0 0.0 1674.0 478.8 0.09 0.00 5256. 1212 0.09 0.00 0.00
114.0 0.0 1657.8 476.8 0.09 0.00 52.58 1211 0.09 0.00 0.00
117.0 0.0 1641.4 476.8 0.09 0.00 52.56 12.10 0.09 0.00 0.00
120.0 0.0 16252 476.8 0.09 0.00 5256 1209 0.09 0.00 0.00
123.0 0.0 1609.0 476.8 0.09 0.00 5256 12.08 0.09 0.00 0.00
126.0 0.0 1593.0 476.8 0.09 0.00 52.56 12.08 0.09 0.00 0.00
129.0 0.0 1577.0 476.8 0.09 0.00 52.56 1207 0.09 0.00 0.00
1320 0.0 .1581.0 476.8 0.09 0.00 5255 12.06 0.09 0.00 0.00
135.0 0:0 15452 478.8 0.09 0.00 5255 1205 0.09 0.00 0.00
138.0 0.0 1529.4 478.8 0.09 0.00 5255 1204 0.09 0.00 0.00
141.0 0.0 1513.7 476.8 0.09 0.00 52.55 12.03 0.09 0.00 0.00
144.0 0.0 1498.0 476.8 0.09 0.00 5255 12.02 0.09 0.00 0.00
P7(apl0yr

147.
150.
153.
156.
159.
1n
343;0
248:0
249A
2520
255:0
258:0
..281:0
321
324
327
357
387.
1436.0
1420.7
1405.5
1390.3
13752
478.
1286.1 476.
1271.5 478.
1256.9 476:
12425 478:
1228.1 478:
1213.7 476:
1199.5 476.1
1185.3 478.1
11712 478.1
1157:2 478.1
11432 478.1
1129.4 476.1
1'175:5 476.1
1101.8 478.!
1088.1 47B:!
.0 987:~
.0 968.E
0 955.7
0 9428
0 930.1
783.
891.E
680..'
689.:
658.E
647.8
637.1
626.4
615.8
805.4
595.0
584.7
an.1
467.8
458.7
449.6
440.7
431.8
0.09 0.00 52.5 5 1201 0.09 0.0 0 0.00
0.09 0.00 525 5 12.01 0.09 0.0 0 0.00
0.09 0.00 525 5 12.00 0.09 0.0 0 0.00
0.09 0.00 52.5 5 11.99 0.09 0.0 0 0.00
0.08 0.00 525 5 11.98 0.08 0.0 0 0.00
D_08 0.00 525 5 11.97 0.08 0.0 0 0.00
0.08 0.00 52.5 5 11.96 0.06 0.0 0 0.00
D.OS 0:00 525 5 11.95 0.08 0.0 0 0.00
D.08 0.00 525 5 11.84 0.08 0.0 0 0.00
D.08 0.00 52.5 5 11.94 0.08 0.0 0 0.00
).os o.oo s2.s s 11.93 o.os o.o o o.oo
).08 0.00 525 5 11.92 0.08 0.0 0 0.00
).DB 0.00 52.5 5 11.91 0.08 0.0 0 0.00
108 0.00 525 5 11.90 0.08 0.0 0 0.00
1.08 0.00 525 5 11.89 0.08 D.0 0 0.00
).OB 0.00 525 5 11.88 0.08 0.0 0 0.00
108 0.00 525 5 11.88 0.08 OA O 0.00
1.08 0.00 525 5 11.87 0.08 0.0 0 0.00
1.08 0.00 52.5 5 11.86 0.08 0.0 0 0.00
108 0.00 525 5 11.85 0.08 0.0 0 0.00
I.OB 0.00 5255 11:84 0.08 0.00 0.00
1.08 0.00 52.55 11.83 0.08 0.00 0.00
1.08 0.00 5255 11.82 O.OB 0.00 0.00.
1.08 0.00 5255 11.82 0.08 0.00 0.00
LOB 0.00 5255 11.81 O.OB 0.00 0.00
LOB 0.00 5255 11.80 0.08 0.00 0.00
':08 0.00 5254 11.79 0.08 0.00 0.00
.08 0.00 5254 11.78 0.06 0.00 0.00
.08 0.00 52.54 11.77 0.08 0.00 0.00
.07 0.00 52.Sa 11.n o.07 0.00 0.00
.m o.oo 5254 11.75 o.07 0.00 0.00
.07 0.00 5254 11.75 0:07 0.00 0.00
.07 0.00 5254 11.74 0.07 0.00 0.00
.07 0.00 5254 11.73 0.07 0.00 0.00
.07 0.00 5254 11.72 0.07 OAO 0.00
07 0.00 5254 11.72 0.0T 0.00 0.00
07 0:00 5254 11.71 0.07 0:00 0.00
O7. 0:00 5254 11.70 0.07 0:00 0.00
07 0.00 5254 11.89 0.07 0.00 0.00
07 0.00 5254 11:88 0.07 0:00 0.00
07 0:00 5254 11.67. 0.07 0:00 000
07 0.00 5254 11.67 0.07 0:00 0.00
07 0.00 52:54 11:66 0.07 0:00 0.00
07 0:00 5254 11.65 0.07 0.00 0.00
07 0.00 5254 71. 0.07 0.00 0.00
D7 0.00 5254 11.63 0.07 0.00 0.00
D7 0.00 5254 11.63 0.07 0.00 0.00
D7 0.00 5254 11.62 0.07 0.00 0.00
D7 Q00 5254 11.61 0.07 0.00 0.00
D7 0.00 5254 17.60 0.07 0.00 0.00
)7 0.00 52.54 11.59 0.07 0:00 0.00
)7 0.00 5254 11.59 0.07 0.00 0.00
)8 0.00 5254 11.58 0.06 0:00 0.00
>8 0:00 5254 11.57 0.06 0.00 0.00
)6 0.00 52.54 11.56 0.06 0.00 0.00
I6 0.00 5254 11.55 0.06 0.00 0.00
)6 0.00 5254 11.55 0.06 0.00 0.00
16 0.00 52.54 11.54 0.06 0.00 0.00
I6 0.00 52.54 11.53 0.08 0.00 0.00
I6 0.00 5253 11.52 0.06 0.00 0.00
18 0.00 5253 .11.51 0.06 0.00 0.00
IB 0.00 52.53 11.51 0.06 0.00 0.00
16 0.00 5253 11.50 0.06 0.00 0.00
i6 0.00 5253 11.49 0.06 0.00 0.00
8 0.00 5253 11.48 0.06 0.00 0.00
6 0.00 5253 11.47 0.06 0.00 0.00
6 0.00 5253 11.47 0.06 0.00 0.00
6 0.00 52.53 11.48 0.06 0.00 0.00
6 0.00 5253 11.45 0.08 0.00 0.00
6 0.00 5253 11.44 0.06 0.00 0.00
B 0.00 52.53 11.44 0.06 0.00 0.00
B 0.00 52.53 11.43 0.06 0.00 0.00
B 0.00 5253 11.42 0.06 0.00 0.00
5 0.00 5253 11.41 0.05 0.00 0.00
5 0.00 5253 11.41 0.05 0.00 0.00
S 0.00 5253 11.40 0.05 0.00 0.00
S 0.00 5253 11.39 0.05 0.00 0.00
i 0.00 5253 11.38 0.05 0.00 0.00
i 0.00 52.53 11.38 0.05 0.00 0.00
i 0.00 5253 11.37 0.05 0.00 0.00
i o.o0 52.53 11.36 0.05 0.00 0.00
i 0.00 5253 11.36 0.05 0.00 0.00
i 0.00 5253 11.35 0.05 0.00 0.00
i 0.00 5253 11.34 0.05 0.00 0.00
i 0.00 5253 11.33 0.05 0.00 0.00
i 0.00 5253 11.33 0.05 0.00 0.00
P7~10yr

Clurinsaw Routing Method
Project Name: Wakwt Street Parts
Project # : Bioreterttion Basin #1
Date : 8/8/2007
Operator: WDM
Title : 1 DO Year Storm
Hydrogreph:
Op = 8.8 CFS
Tp = 5.0 minutes
dT = 3.0 minutes
StageStorage
Kc = 2138.00
b = 1.33
z, = a7s.o feet
Initial Water Level
~ = 476.1 feet
Computed Rewlts
Nwrnai Surf. Area = 1337. SF
Max Surf. Area = 3008. SF
Peak Elev. = 477.20 feet
Peale Stage = 12 feet
Peak Outliow = 4A6 CFS
Vdume Stored = 2624.8 ft
Mih:hell Westendorf, PA
1709 Legion Road, Suite 201
Chapel Hi9, NC 27517
Weir Box / Bartel
N barrels = 1.00
Opening H = 0.00 feet
Opening L = 0.00 feet
Cw = 0.00
Crest Faev. = 0.00 feet
Barrel Dia. = 15.00 inches
Cd = 0.60
Bar. Invert = 472.00 feet
Orifice:
N =
1.00
D = 200 inches
Cd = 0.60
IrneR = 476.00 Meet
weir 1:
L = 16.00 feet
z,'= an.oo feet
Cw = 3.00
Weir 2: 0.00
L = 0.00 feet
Zen.- 0.00 feet
Ctrr= 0.00
System Loading and Response
30.0
- _Intbw
25.o p„yb,,,
20.0
~ ts.o
3
0
LL
to.o
s.o
o.o
o.o so.o too.o tso.o zoo.o
Time (min)
Tieee
min YrOorr
efs Stprage Stage Outlbw
Cfa Opening (W)
cfa Opening (O)
efs HYY Bartel
cfs Orttice
cis Weir 1
efs Weir 2
cfs
4 0 OA 100.8 '476.1 11.00 0.00 0.00 11.01 0.00 0.00 0.00
3. 0 5.7 100:8 - .476.1 0.01 0.00 0.00 11.01 0.01 0.00 0.00
6.0 Z9 1132.0 476.8 0.08 0.00 0.00 11.81 0.08 0.00 0.00
S_0 3.7 2548.3 ' 477:1 269 0.00 0.90 1258 0.91 258 0.00
120 1.7 2725.6 4772 .4.40 0.00 0.00 1264 0.11 4.35 0.00
954 0.8 2225.4 477.0 0:37 0.00 ,0.00 1240 . 0.10 . 027 0.00
18.0 0.4 2297.8 477.1 0.75 0.00 0.00 1244 0.10 0~5 0.00
29.0 0.2 ,2220,5 477.0 0:37 0.00 0.00 1240 0.10 027 0.00
24.0 0.1 2188.3 477.0 0.22 0.00 0.00 1238 0:10 0.12 0.00
.27:9 OA 2161.9 477A 0.14 0.00 0.00 1237 0.10 0.04 0.00
30.0 0.0 2142.3 477.0 OJ 1 0.00 0.00 12.36 0.10 0.01 0.00
33A 9.0 2'120.1 477.0 0.10 0.00 0.00 1235 0.90 0.00 0.00
36.9 0:0 2109.4 477.0 010 0.00 0.90 1235 0.10 0.00 0.00
39A 0.0 2092.0 477.0 0.10 0.00 0.00 1234 0,10 0:00 0.00
420 0.0 2074.3 477.0 0.10 0.00 0.00 1233 0.10 0.00 0.00
45.0 0.0 2056.6 477.0 0.10 0.00 0.00 1232 0.10 0.00 0.00
48:0 O.D 2038.8 477.0 0.10 0.00 0.00 1231 0.10 0.00 0.00
51.0 0.0 2021.1 477.0 0.10 0.00 0.00 1230 0.10 0.00 0:00
54.0 0.0 2003.5 477.0 0.10 0.00 0.00 1229 0.10 0.00 0.00
57.0 0.0 1985.9 476.9 0.10 0.00 0.00 1228 0.10 0.00 0.00
60.0 0.0 1988.4 478.9 0.10 0.00 0.00 1227 0.10 0.00 0.00
63.0 0.0 1950.9 476.9 0.10 0.00 0.00 1227 0.10 0.00 0.00
86.0 0.0 1933.5 476.9 0.10 0.00 0.00 12.26 0.10 0.00 0.00
69.0 0.0 1916.1 476.9 0.10 0.00 0.00 1225 0.10 0.00 0.00
720 0.0 1898.8 476.9 0.10 0.00 0.00 1224 0.10 0.00 0.00
75.0 0.0 1881.6 476.9 0.10 0.00 0.00 1223 0.10 0.00 0.00
78.0 0.0 1884.5 476.9 0.09 0.00 0.00 12.22 0.09 0.00 0.00
81.0 0.0 1847.4 476.9 0.09 0.00 0.00 1221 0.09 0.00 0.00
84.0 0.0 1830.4 476.9 0.09 0.00 0.00 12.20 0.09 0.00 0.00
87.0 0.0 1813.4 478.9 0.09 0.00 0.00 12.19 0.09 0.00 0.00
90.0 0.0 1796.5 476.9 0.09 0.00 0.00 1218 0.09 0.00 0.00
93.0 0.0 1779.7 478.9 0.09 0.00 0.00 1218 0.09 0.00 0.00
98.0 0.0 17629 476.9 0.09 0.00 0.00 1217 0.09 0.00 0.00
99.0 0.0 17482 478.9 0.09 0.00 0.00 12.16 0.09 0.00 0.00
102.0 0.0 1729.6 478.9 0.09 0.00 0.00 1215 0.09 0.00 0.00
105.0 0.0 1713.0 476.8 0.09 0.00 0.00 12.14 0.09 0.00 0.00
108.0 0.0 1896.6 478.8 0_Q9 0.00 0.00 1213 0.09 0.00 0.00
111.0 0.0 1680.1 476.8 0.09 0.00 0.00 1212 0.09 0.00 0.00
114.0 0.0 1683.8 476.8 0.09 0.00 0.00 1211 0.09 0.00 0.00
117.0 0.0 1647.5 476.8 0.09 0.00 0.00 1211 0.08 0.00 0.00
120.0 0.0 16312 4711.8 0.09 0.00 0.00 1210 0.09 0.00 0.00
123.0 0.0 1615.1 478.8 0.09 0.00 0.00 12.09 0.09 0.00 0.00
126.0 0.0 1599.0 476.8 0.09 0.00 0.00 1208 0.09 0.00 0.00
129.0 0.0 1583.0 478.8 0.08 0.00 0.00 1207 0.09 0.00 0.00
1320 0.0 1567.0 476.8 0.09 0.00 0.00 12.06 0.09 0.00 0.00
135.0 0.0 1551.1 476:8 0.09 400 0.00 1205 0.09 0.00 0.00
138.0 0.0 1535.3 476.8 0.09 0.00 0.00 1204 0.09 0.00 0.00
141.0 0.0 1519.5 476.8 0.09 0.00 0.00 1203 0.09 0.00 0.00
144.0 0.0 1503.9 476.8 0.09 0.00 0.00 12.03 0.09 0.00 0.00
147.0 0.0 1488.2 476.8 0.09 0.00 0.00 12.02 0:09 0.00 0.00
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1488.2 478.8 0.09 0.0 0 0.0 0 12.0 2 0.09
1472.7 476.8 0.09 0.0 0 0.0 0 12.0 1 0.09
1457.2 476.7 0.09 0.0 0 0.0 0 120 0 0.09
1441.8 476.7 0.09 0.0 0 0.0 0 11.9 9 0.09
1426.5 476.7 0.08 D.0 0 0:0 0 11.9 8 0.08
1411.2 478.7 0.08 0.0 0 0.0 0 11.9 7 0.08
1396.0 476.7 0.08 0.0 0 0.0 0 11.9 7 0.08
1380.9 478.7 0.08 0.0 0 0.0 0 11.9 6 0.08
1365.8 476.7 0.08 0.0 0 0.0 0 11.9 5 0.08
1350.8 478.7 0.08 0.0 0 • 0.0 0 11.9 4 0.08
1335.9 478.7 0.08 0.0 0 0.0 0 11.9 3 0.08
1321.1 476.7 0.08 0.0 0 0.0 0 11.9 2 0.08',
1308.3 476.7 0:08 0.0 0 0:0 0 11.9 1 0.08
1291.6 478.7 0.08 0.0 0 aD:0 0 1.1.9 0 0.08
1278.9 478.7 0.08 0.0 0 0.0 0 11.9 0 0:08
1252.4 478.7 0.08 0.0 0 0.0 0 11.8 9 0.08
1247.9 478.7 0.08. ; 0.0 0 -0.0 0 f 1.8 8 0.08
1233.5 478.7 0.08 0:0 0 ' 0:00 11.87 0:08
1219.1 478.7 0:08 ` 0:00 0.00 11.88 0.08
1204.8 476:8 .0:08 0.00 0.00 41:85 0.08
1190.6 478.8 0:08 0.00 0.00 11.84 0.08
1178.5 476.8 0.08 0.00 0.00 ' 11.84 0.08
11624 476:8 0.08 0:00 ; 0.00 11!83 0.08
1148.5 478:B . O:OB 0.00 ; ` 0.00 11.82 0.08
1134.5 478.8 ' 0. 0.00 0.00 11:81 0.08
1120:7 478.6 0.08 0.00 0.00 11:80 0.08
1108.9 478.8 -0.08 0.00 0:00 11.79 .0.08
1093.3 476.6 0.08 0.00 0.00 11.79 0.08
1079.6 476.8 0.08 0.00 0:00 11..78 0.08
1066.1 476.8 0: 0.00 0.00 ' 11:77 0.07
1052.8 478:8 0.07 0.00 >0.00 1 T! 78 0.07
1039.2 476.6 0.07 0.00 0.00 11:75 0.07
1025.9 478.6 0.07 0.00 0.00 11.74 007
0.0 947.8
0:0 934:8
0:0 9221
OA 909.5
0.0 897.0
0.0 884:5
0.0 8721
D:0 859.8
D.0 847.5
787.5
775.8
764.1
7525
741.0
729.8
641.1
588.1
558.0
548.0
538.1
528.3
518.6
&B .0.07 D.06 0_ 1i:7d 0.07
6:8 0.07 0:00 0:00 11:73 0.07
6:8 OA7 0.00. . .0.00 11.72 0.07
6:8 0.07 D.00 ' 0.00 11:71 D.07
5:5 ...0.07 0:00 0.00 11.70 0.07
5.5' 0. 0.00 0:00 11:89 0.07
%5 0.07 0:00 ;0:00 it;89 0.07
3.5 0.07 0:00 0.00 U88 0:07
0.00
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11:66 O.Oi
11.85 O.Oi
11:64 O.Oi
11.84 O.Oi
11:63 i0.0i
11:62 O.Oi
11.61. 0.07
11.60 0.07
11.60 0.07
11.59 0.07
11.58 0.Ofi
11.57 0.08
11.56 0.08
11.56 0.08
11.55 0.08
11.54 QO6
11. 0.06
11.52 O.Q6
11.52 0.06
11.51 0.06
11.50 0.06
11.49 0.08
11.49 0.08'
11.48 0.08
11.47 0.06
11.46 0.06
11.45 0.06
11.45 0.06
11.44 0.06
11.43 0.06
11.42 0.06
11.42 0.06
11.41 0.05
11.40 0.05
11.39 0.05
11.39 0.05
11.38 0.05
0.00 0.00
0.00 0.00
0.00 0.00
0.00 0.00
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0.00 0.00
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Culvert Report
Hydraflow Express by Intelisolve
Cir Culvert
Invert Elev Dn (ft) = 474.79
Pipe Length (ft) = 100.00
Slope (%) = 2.00
Invert Elev Up (ft) = 476.79
Rise (in) = 30A
Shape =Cir
Span (in) = 30.0
No. Barrels = 1
n-Value = 0.012
Inlef:Edge = Sq;Edge
Coeff. K,M,c,Y,k = 0.0098,_ 2, 0.0398, 0.67, 0.5
Embankment
Top :Elevation (ft) = 482:00.
Top Width (ft) = 90..00
Crest -Width (ft) = 300.00
Elev, (ft) Profile
483:00
48200
481.00
480.00
479.00
478.00
477.00
476.00
475.00
474.00
473.00
Hw Depth (ft)
6.21

Hw

0

5.21
4.21
3.21
2.21
1.21
0.21
-0.79
-1.79
-2.79
_~ ~Q
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Reach (ft)
Wednesday, Apr 11 2007, 7:40 PM
Calculations
Qmin (cfs) = 37.23
Qmax (cfs) = 37.23
Tailwater Elev (ft) _ (dc+D)/2
Highlighted
Qtotal (cfs) = 37.23
Qppe (cfs) _ 37.23
Qovertop (cfs) = 0.00
Veloc Dn (ft/s) = 7.95
Veloc Up (ft/s) = 8.68
HGL Dn (ft) = 477.06
HGL Up (ft) = 478.83
Hw Elev (ft) = 480.73
Hw/D (ft) = 1.58
Flow Regime =Inlet Control

Town of Cary -Online Map
wIV!o~'Ca~
Page 1 of 1

DISCLAIMER: The information contained on this page is NOT to be construed or used as a "legal description". Map information is
believed to be accurate but accuracy is not guaranteed. In no event will the Town of Cary be liable for any damages, including loss of
data, lost profits, business interruption, loss of business information or other pecuniary loss that might arise from the use of this map or
the information it contains.
http://209.42.194.57/CaryMap/ViewMap. aspx?ItemID= l 1 &PortalID=1 4/ 11 /2007

R[P RAP APRON DESIGN F"OF~ CULVERTS
oArE: _ ~ 9 0
rn~~t~i• .UG17niir ~!'' l~lG,
------. LO.,ATION: ~ /l.~C DESIGNED BY:
PROJECT N0.-
DE5~2fP?ION__ CHECKED BY:

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LONE f A FlNf 3 X 0, ~ X D 11' ~
7 2 B ll~yT 3 X 0 6 X 0 16'
3 i LfED1Ur( 4 X Da .8 X Da 14'
4 1 NERVY 4 X D. 8 X 0 36"
5 2 HE.gVY S X D, ? D X Da 36'
6 Z NERVY 5 X 0, t0 X D° 36"
~ REQUiRfS tARGEk STONE ~R ANOTNI:R TYPE
7F DEVICE, DfS1C„Y IS 8c'YDJt'U THi: SCOPE
`OF 7H1S PROCEOCAtE.
W10TN _ OiAAIETFJ3 + 0.4 (Lfr1GTHj 6' 1rI1Nl+~l
1 _ LENGTii 70 PROTECT' GAYERT
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Q 5 f 0 ~5 2a ~ ~ ~ ~t wEra~ LESS nuw t3 Les j
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ROTES: ]..FOR WLT1P(,F CULVERTS USE p 1 6O1C S1i4Lt N'ElCH A7 lEAS7 10Q
2• (1SE NEXT iflt7ffR ZUt~E FOR GRADESISTEEPER° FOR .tMGLE CULVFItT. CLASS 2 2250 L95 EACH. N01fORE TkW 5z
J. FOR P1Pf ARC?{. MCN.. 8D7C U9L~'ER7. PAYED ~JAHNEL OUTLETS EACH. N'EtQI LESS 9HAN 50 L8S
usE o, _ ~ sECrrowL .IKEA ~ ~,~ ~~,. EROSION COM7ROG STONE ~
SOiitCEg '8~tfdC ~c CFLWNEI tlfllNG PROCEDURES', tiE1Y ?'CVtlC OfPARriE-!T OF CLASS A 1QiC 7a° ~ "BDTTW S17E5.
TA.AHSPORTATIdN, DIVISION OF DESIGN Mr ~JtSTRLCT!ON• 1771. ~• ~ CftADATfON SPECIF(E,p.
CLASS 8 ?5-SOO 5-75' NO 6RADATtON SPEC;FIEO.
STR~ Q-FLO'r~ G OUTLET DtPTH ZONE ~
.PRON APRON APROty ~ STONE ~ REMARKS
(CFS} ° VEC OF FLC?W'
a

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(FPS) (FT) LENGTH
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(FT? (tN)
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Depth-Duration-Frequency Table
Location: ~ Raleigh-Durham, NC
Exhibit 2 by H. R. Malcom, P.E.
C. E. Dept, NCSU
Raleigh, NC
Return Period -~
Duration, 2-yr 5-yr 10-yr 25-yr 50-yr 100-yr
[in] [~] [mil [mil [~] [~]
5 rein 0.48 0.55 0.60 0.68 0.75 0.81
10 min 0.79 0.92 1.02 1.17 1.28 1.40
15 min 1.01 1.18 1.31 1.51 1.66 1.81
30 min 1.35 1.64 1.85 2.16 2.40 2.64
60 min 1.70 2.12 2.41 2.84 3.17 3.50
2 hr 1.91 2.40 2.74 3.23 3.61 4.00
3 hr 2.12 2.68 3.07 3.62 4.06 4.49
6 hr 2.65 3.38 3.90 4.62 5.19 5.75
12 hr 3.13 4.02 4.64 5.52 6.20 6.88
24 hr 3.60 4.65 5.3 8 6.41 7.21 8.00
Intensity-Duration-Frequency Table
Location: -~ Raleigh-Durham, NC
Return Period ~
Duration 2-yr
[~] 5-yr
[ice] 10-yr
[ice] 25-yr
[ice] 50-yr
[~/~'] 100-yr
[~/~']
5 min 5.76 6.58 7.22 8.19 8.96 9.72
10 min 4,76 5.54 6.13 7.01 7.71 8.40
15 min 4.04 4.74 5.25 6.03 6.64 7.24
30 min 2.70 3.28 3.71 4.32 4.80 5.28
60 min 1.70 2.12 2.41 2.84 3.17 3.50
Z hr 0.95 1.20 1.37 1.62 1.81 2.00
3 hr 0.71 0.89 1.02 1.21 1.35 1.50
6 hr 0.44 0.56 0.65 0.77 0.86 0.96
12 hr 0.26 0.33 0.39 0.46 0.52 0.57
24 hr 0.15 0.19 0.22 0.27 0.30 0.33
Input Data:
Location
Duration
-Durham, NC
IDF Equations:
for 5 < T < 120 min
2-yr P 100-yr P Source
[in] [in]
5 nun 0.48 0.81
15 min 1.01 1.81
60 min 1.70 3.50
24 - hr 3.60 8.00
F-- Data j
NOAA HYDRO-35
NOAA HYDRO-35
NOAA HYDRO-35
US WB TP-40
VI-3
R h
2 132 1
5 169 21
10 195 22
25 232 23
50 261 24
100 290 25

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Exhibit 1
Table of Rational runoff coefficients
Description C Source
Roof,, inclined 1.00 Malcom
Street, driveway, sidewalk 0.95 Chow, 1964
Parking of 0.90 Malcom
Roof, flat 0.90 Malcom
Comtnenrial,: generalized 0.85 Malcom
Aparmnents, drools, churches 0.60 WSSC, c.1968
Residences, 10 dwellings/acre 0.60 Malcom
Residences, 6 dwellings/acre 0.55 Malcom
Residences, 4 dwellngs/a~cre 0.50 Malcom
Residences, 2 dwellings/acre 0.,40
Unimproved cleared area 0.35 Malcom
Lawn, densc soil, steep >730 0.35 Chow, :1:964
Playground 0.35 Chow, .1964
Park, cetnetcry 0.25 Chow, 1964
Lawn, dense-soil, avg 2-7g'o 0,22 Chow, 1964
Wooded, sparse ground litter 0.20 Malcom
Lawn, dense soil, flat 23'0 0.17 Chow, 1.964
Lawn,-sandy, avg 2-73'0. 0.15 Chow, I964
Lawn, sandy,'flat Q9o 0.10 Chow, 1964
'Wooded, deep ground litter 0.10 Malcom
VI-2

i
Hydrology Report
Hydraflow Egress by Intelisolve Thursday, Sep 13 2007, 9:56 AM
Bioretention
Hydrograph type =Rational Peak discharge (cfs) = 36.99
Storm frequency (yrs) = 25. Time interval (min) = 1
Drainage area (ac) = 6.900 Runoff coeff. (C) = 0.65
Rainfall listen (irUhr) = 8.247 Tc by User (min) = 5
IDF Curve = burham.IDF Rec limb factor = 1.00
Hydrograph Volume = 11,097 (cult); 0.255 (acft)
Q (~)
40.00
30.00
20.00
10.00
0.00 ~
0
Runoff Hyd - Qp = 36.99 (cfs)
Runoff Hydrogcaph
25-yr frequency
5
Q (cfs)
40.00
30.00
20.00
10.00
~- 0.00
10
Time (min)

Hydraflow Express -Channel Report - 09/13!07,9:48 AM 1

Hydraflow Express -Channel Report - 09/13/07,9:48 AM 2

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0 0.000- ~ 0.00 0.000 0.00
1 7.398 ~ 221:93 0.000. 0.00
2 14.80 i 887.74 0.000 0.00
3
----- 22.19 i 1,997 0.000 0.00
4 29:59 ~ 3,551 ~ 0.000 0.00
5 36.99 ~ 5,548. - : 0.000 0.00
6 29.59 7,546 0.000 0.00
7 22:19 j 9,099 ~ 0.000 0.00
8 14.80 10,209 0.000 0.00

9
7.398 {
10,875
0.000
0.00
10 0.000 11,097 0.000 0.00
Hydraflow Express - Bioretention - 09/13/07,9:48 AM 1

b~ ._ ~' ~_
auired Storage .
~ ~.. ,, --
0:00..
0.00.
0.00
0.00
0.00
Hydraflow Express - Bioretention -09/13/07,9:48 AM 2

~ .,
Channel Report
Hydraflow Express by Intelisolve
<Name>
Trapezoidal
Botom Width (ft} = 2.50
Side .Slope (z1) = 1.00:
Total.-Depth (ft) = 2:00
Invert Elev (fE) = 456.50
Slope'(%) = 2.50
N-Value = 0.022
Calculations
Compute by Known Q
Known Q {cfs) = 36:99
Elev (ft)
X59
00
.
458:50

458.00
457.50
457.00
456.50
456.00
0 1 2 3
Section
4 5
Reach (ft)
Thursday, Sep 13 2007, 9:50 AM
Highlighted
Depth (ft) = 1.17
Q (cfs) = 36.99
Area (sgft) = 4.29
Velocity (ft/s) = 8.61
Wetted Perim (ft) = 5.81
Crit Depth, Yc (ft) = 1.54
Top Width (ft) = 4.84
EGL (ft) = 2.32
Depth (ft)
2.50
2.00
1.50
1.00
0.50
0.00
-0.50
6 7 8 9

0 8-0 1 82
Eros~an Control Calculations
FOR
Walnut Street Park
Cary, NC
,,,~,~~,
Q~t= y
MITCHELL ~ WESTENDORF, P.A.
~- _-~
ENGINEERING & SURVEYING
1709 Legion Road, Suite 201
Chape! till!, North Carolina 275 ( 7
P 932-4567 f 932-9325
October, 2007
22547 _
• _ V ~
:,y ~ F'NG~ l~~~G~~v
Submitted by: ''%,F~V~p~~+~~~~~~~
Q~~~ad~D
JAN 2 4 2008
DENR • WATER QUALITY
WETLANDS AND STDRMWATER BRAiiCK

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