20020831 Ver 1_Stormwater Info_20030729

1
1
1
~~A/~
~/ J
~ / Q~~
~~
O~ `~1~
oZ
~,
~~
„~)'!!
~ !!ii ~
.~~JI _. iy t_~ ,
1 ~....._
wenn~~~; _ ~._
WATt:ii (~,
The Park at Langston
Wake County, NC
Drainage and Erosion Control Calculations
Submitted by CH Engineering
4601 Lake Boone Trail
Raleigh, NC
919-788-0224
sEa.
3046
~~,spb

Contents
Nitrogen Loading Calculations 1 - 3
Stormwater Management Storage Calculations 4 - 5
Storm Pipe Calculations 6 - 7
Henderson Rd Pipe system (Pipe 12-1) 8 - 11
Henderson Rd Pipe 7 -6 12 - 17
Henderson Rd Pipe 2 18 - 20
Alphawood Dr Pipe 3 21 - 22
Tributary Dr Pipe System (pipe 4) 23 - 27
Optimist Ridge Pipe 9-10 28 - 29
Level Spreaders 30
Roadway Ditches 31- 51
GI Analysis 52 -56
Trapezoidal ditches 57 - 61
Details 62
Sediment Trap designs 63 - 73
Maps 74 - 78

waxy )~AX ~vr I-~agc~. dos- j l1c Po..,k fit t•-0.~5-+-0~
r~
r Harr 1. RlpaHan Bun'er5
~~ Arse includes. riparian b~ers'~ (l ~Jc 6Q Yes [ lExe'",P;
!f yds, ~5U faot ~ 100 foot
' River t3as~n'? Neuse (1 C;epe pear
Basis for exernot~or•-_- __---__..._--_--_,_.--__.___---
Show bur?'ers on site plan.
~~ "~ Part It. Nitrogen Calculations (Method 1, Appencllx C):
a. Subdivision infoftnaton:
fJumber of Icts _` L~~.__ ra~r8raga house size
Number cf krts ; acre _ 1 • 3~,;~,~ ~~ 1 Amount of Right-of-Way
Total area of lots (excluding .___ 3 Z • y z. w ~ Percent of Right-cf•V1~e~y
R/W and cpen space) 18.8 2 /1 ~ tnat is impervious area
Average Ict sr<e - -__t ~~ ~>~-~~s ~ Total estimated impervio;~s 8re2

~z7s sF
3 • ~l A c
S ~_ /_
b. Pre-development loading: ~ ®xport

Type ~' Land Cover Area TN export coe~t. from use
(acres) (Ibs/ac/yr) (Ibslyr)
Permanently protected undisturbed open space ; .
('ores>:, unmown meadow) 3 2 • ~ 2 0.60
r q • .4 s'
Permanently protected managed open spare _ _____
_____
i
(grass, landscaping. etc. f
r 1.20
Impervious Area p 21.20
TOTA:. q
Nitrogen Loading Rate (Ibs/ac/yr) = _ o • 6 __
c. Aost-development loading:

Tyoa of Land Covet
Permanently protected undisturbed open spe~.e
(forest, unmown meadow)
Permanently protected rnanaged opera space
(grass, 1$ndsoap~ng etc. )
P,Igtri-of-Way (read 7N ex;~ort from Gr~rht)
Lott (read '1'N eKrx~rt ft ;m Graph ?)
DOTAL
TN export
Arra TN export coeff, from use
(acres) {tbslac/yr) (Ibslyr)

•
- 0.60
1.2A -l
r^-
-
' 3•ti z 7. 2.

Nitrogen Loadin;~ Rate (Ibs/ar./yr) = .~.2 ' [/ ~
NitrogEn Lc+ad after HMPs = _ ~ ~ f ~
~Jit~•ogett i.aad 4tfset by P~aymenis =
Net cl~a.nCe In on-site NLoad =
Part Nl. t;u»u'o! of peak cStormw~ter Flow
Calculated Pre-development Peak rlae/ __O__7~ G~-'S
,~~ Calcu~ated Past-develaprrent Peak riw~_ b ~?o
I, the undersigned, certify tc the best of my kna~,lradga that fire above information is rorreci (affl~c seal),
~`''~Z~ 1 ~aRp~''%
0
a ~,, ~OQoQOE L~~~~/li9r';~,
o -, (•
_ °
° S E A ~ --~
° °
° 1 40 °
'° ° c w
/J o ~
'•/ c°° a
nr,,yiCoe~F~GI PlE~~° cS*'
,AOO ~~~ CHAMP'' p90~0
°'ejaenseaae~60° ~ 6 ~ o a

1 Graphs for use with Method 9: Reaidentiai Sites with no known building footprints.
~~

~r~iph 1: "~ ~I~trcagl~-n ~xpart Pram ~t~ght-+c~-Wayr
T _ __
z
4
/~
/~

..~.--
t
L ~'
~ ~~.c:~
$, ~W,c~
s~
"~ ~.~;.
Par+cent~g+a od fl~$h#-+o~ Way t.~at is Pavs~men#
a..r~
(!'~f',,

t3~h 2: Tot~-1 ~itr~rge~'r ~xpt~t from tarts
~'r~! Nitrggen ~xpcart frrarr~ i ~Es
f2.~-
"(1.D7
r 4'i.~(1
e'~T
~6
~. 6.4d
W
~ ~4.~J
2ik~
U.:d(e
ar `~ ~ fi r R ' 7 ^ 4 ~!i 1 t~ 20 72 24 26 2~ :'f'".? :'
Wumb9~ Gf t~weiHtlg Units psr Acrd

.._
.t~~" -~- b- ~-_Ci`.~I
~'- 2 ~~. c. 1Year storm quanltity Calculations

.,., ~,., , Pre Development 0.80 cfs
Post Development 1.80 cfs
difference 1.00 cfs Retain this amount during the 24 hour 1 year storm
I ~~
~., ~ ~\,
(..~ ... ry .. ~._
~ ~ t~~
Total Detained on site
Pipe 1 Henderson Road 0.15 cfs (from chainsaw routing)
BMP Tributary 0.25 cfs
Trapezoidal Ditch Lots 13-15 0.10 cfs
=~- ~~;_' %~ Trapezoidal Ditch Lots 11-12 0.20 cfs
Trapezoidal Ditch Lots 12-13 0.10 cfs
Trapezoidal Ditch Lots 23-26 0.10 cfs
BMP Optimist Ridge 0.10 cfs
' 1.00 cfs
~~' ~ ~~. ~ Total 1 year post development flow 0.80 cfs
~~ ~~
,:~~ ~..
_~ ~ _ ~
~` _
~:~
~ ~ ~::

~ ~ ~ >~ ' ~ ~
Strom Pipe Summary
~ ~ ~ ~ ~ r ~ as ~ ~ ~ ~

Pipe
Size
From
Top
Invert
Len th
Slope
To
Top
Invert Energy
Dissipator
1 36" RCP GI 2 356.59 352.31 123.00 0.50 FES 351.50 ED 1
2 18° RCP 373.80 85.00 0.50 FES 370.00 ED 2
3 2-36" RCP 367.48 80.00 1.30 366.43 ED 4
4 24" RCP GI 5 373.00 370.00 95.00 1.05 FES 369.00
5 30" CMP MH 2 360.30 354.52 100.00 0.00 MH 3 358.50 354.52
6 18° RCP MH 4 358.00 354.00 85.00 1.76 FES 352.50 ED 6
7 18" RCP GI 6 359.00 355.00 56.00 0.50 MH 2 360.30 354.72
9 24" RCP GI 1 375.00 370.00 82.00 1.22 FES 369.00 ED 5
10 18" RCP GI 3 373.50 370.50 100.00 0.50 GI 1 375.00 370.00
11 36" RCP MH 1 362.25 354.13 35.00 1.48 GI 4 359.50 353.61
12 36" RCP YI 1 365.00 361.25 207.00 3.34 MH 1 362.25 354.33
13 36" RCP GI 4 359.50 363.41 73.00 1.50 GI 2 356.59 352.31
14 2" PVC MH 3 358.50 354.52 10.00 3.20 MH 4 358.00 354.20
15 18" RCP MH 3 358.50 355.50 10.00 3.20 MH 4 358.00 355.20

U
G
~ 7 ~
r
p
S
n
D
--~
N
O
O
~Bi
1VORTB CAROlINd
NORrH CAROLINE) STATE H~GH~'yY COhl~17lS5tON
HYDROCRAPHIC OEPT
MAP OF NYDROLO~IC CONTOURS f0,~ U,SE IN DETERiI'IIi1iING
PROJECT DESIGN OlSCHA,~'GE'S
5 .S
=D
m~
--i m
J Z
o°
-n X
m C7

i
i

r.
APPENDIX C
SHEET 3 OF 8
i -~,
t xtiNPL
G ! VEN :
.~YDROLDGJC GONTaUR 5.0
ORf~INAGF f~REf~ 35 AG
SiL1f~G L AREA f UL L BUSJNE 55
HN5 wER
Q io = s9 x i•4 = 54. ~o OF. s
~ 8
~~_ ~
4 3 ~.. '~' ~..
~. ~.`
~ `;-~ ~~
1~5
~ !O _
0.5
w ~w WW
O ~ ~~
V ~aD ~~
v
~~
-,
2, 000
~~aoo
800
600
~~
200
~80 .
~ (00
~~~
''~'
~o
8 ~
~D
I ADO
ro 00
a°o
--~ 200
>_
!00
50 ~
a° ~;
20
~~
W~
O
W~
~_
FOR Y pEVEIRORP~CNT
fRGlORS FD~Q FREQUENCIES
Q 5 GURYE VVALUE X . pp~5
G123 ~~ n X %.35
~g a X •8
Q/00 r rr X ~, !5
4
2
i
!n ``~
5 ~
a ~,
O.
RU/VOFF FRo~! URBAN AREFS
~voRTX cRRo~l/vA s ~rF NTGNWRY coN1Ml551on~
JAN, / ?~ G ZOO.3
~i~a ~, a ~~ - .., _) ~..a
._
<.~?z~. ~~ ~.~~ ~~ ,, ~i . "'7 ~ ~.
C.~ , , ,, -~ ~ -(~ ~' v. , ~ , - ~I ~ t , ~ _ ,
CHART C 200.3
7

8 O 10, 000
16 8 e, 000
15 6 6,000
~~ 144 5,000
4,000
132
3,000
120
2,000
108

96

Extubit 11
EXAMPLE
D•4Y IneAoo (3.S foot)
0.120 tto
)~ x Itw
D fort
n) Y.s e.e
(2) Y.I 7.4
t3) Y.Y 7.7
~0 In fNt
N ,~~
t~
(~) (2)
(3)
0
I , 000
' eoo
84
600
500 ~
72 400
N
= 300 ~+~/ \~~I I,~..
~ w,
~.;>
z N
Z 60 v 200
z /
0 54 a
..! Q -_ _-
_ _.._..-
~ _ ~_
_._:..
V 4Q V 60 __
' ~ _ N 5 y~SCALE` I ENTRANCE
-- 40' D TYPE
W 3~ --
(' 30 (I) Sararo od0o rlt
W
~ ~~ Madrall
0 Q 0 ~ ( t2)) Groor• •nd .its
~~30 - luadroll
~. ~ _ , _ ,_
(3) Groor• and
Q 7 proJoetln~
Ip ---_ 1 ------.._._ ..
Q4
t3 Ta uvo vcolo (2) or (3) proJoct
21 5 norltontonr to wolo (1),tMn
4 uu Nrol9At Inclined Ilno fArouoA
' D and 0 vcalov, or rororoo 00
3 illu~trOt~d.
19
2
15
I.0
12 HEADWATER DEPTH FOR
HEADWATER SCALES 2d3 CONCRETE PIPS CULVERTS
REVISED MAY 1964 WITH INLET CONTROL t_~_~~
BUREAU OF h/~LIC ROAD! JAN. Ittl
_ u1-11 <-_~ \.
E-~U.~ (. ~~ ~. I . 7
~~

. . . ~ ~ ~ . . . . . . . ~ r ~ . . >•
.:~•C~o35
t . a,CX,3
HYDRAULIC GRADE LINE
DATE: SHEET ~OF~
ID NO. PROJECT:~,~c. a.~': ~qr,;;u.~ COUNTY: DESIGNED BY: ~,L
DESCRIPTION: `-= 0. ~ c i ~; :^ _ (7.~~ ~Z - ~~P~t ~ CHECKED BY:
INLET OR
JUNCT. NO. OUTLET
W'S'
ELEV.
DO
Qo
~-o
HEAD LOSSES
o,~,,'c,~.,:11 INLET
W.S.
ELEV.
ELEV
REMARKS
DES. / CONST. ~,r.~ ~5, ~~i Ht H~ He Hb Ht
Z" -. ~ "
= ~ 3Cc 4 3 1'3:~ 0. 4 o O o.2, O. UZS o2 Z5 _ ~'= _-* "~-.v
~
~~ `~ `~ - - 4%~ ~7 C~,22• d o.2 D o,Z~ Z ~ _:~~. ,~ _53
:.o,

T •~
l.. J ~

~D ~ ~~~ ~
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 31 Flow depth (ft) = 1.77
slope S in % : 0.5 Outlet velocity (fps) = 7.119
pipe diameter D in in.: 36
Manning number n :0.013
Pipe diameter (ft) 3.00
Outlet velocity (fps) 7.12
Apron length (ft) 18.00
AVG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
» 6 ~ 22 «
13 Bor1 22
23 2 27

RIDGE E
BRIDGE TECHNOLOGIES, LLC.
' 1 -800-344-21 02
GiZC7SS r~~~~ - ,~c_C.-~E ~.~E.S=_.G`.5l_.~..
-•~
''... ~ ~ <:~yC
ae a , ~:~
.. , ._
l
~_ ..-7 ~ .1..
,~.__
1r-t~.l

l._.~:>~
a r f " _, ~ 1 ~.~,>
.,
_,. ~ ~ ,r, > ~:`., ~ . ,
_, ,. ',
` ( ~ ~ ~_. ~
~ ') r
.y •-
~_. ' .m
~ j
c~) ~ ~,
~! ~
~:,
,...,
1.. >, ~:

~ ' ~ r;
.:_ ~ _.~
~ C~;;j Y' r YI ~ (w
~, . ,

~
, . ~,,;
~

(; ~ Co t~ SAE (p
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow O in cfs :11.3 Flow depth (ft) = 0.74
slope S in % : 4.8 Outlet velocity (fps) = 12.980
pipe diameter D in in.: 18
Manning number n :0.013
Pipe diameter (ft) 1.50
Outlet velocity (fps) 12.98
Apron length (ft) 9.00
AVG DIAM
(inches)
STONE
CLASS
A
B
Bor1
2
THICKNESS
(inches)
» 6
13
23
9
22
22
27

i
d
N
C
n
Q
m
c
0
d

g

g
8
8 E
N E
F
8
8
8
~ S°

a. I"'
~ c
C 8 N
C !!1
m Z
~~t
W .- 'm
U ~ ¢ m
c 0~
m ~ a`~
c ~
ai ai
~ ai
°o r°~ 8
O~ ~ °o °o m
O CU O o° 8 m °o
~ N O O °o o °o
O .-- CM °0 8 8
0 0 0
d

y II II
IR II ;
S
O
II II 11 ~
U D .~ ~ II
II ~
II II ~ ) .-
~ II II
d II d
~
N~
II II
II
N
Z
U N O U O Z O U ~ i -1
3 ~
~ ~ ro ~ U ~
~ 8~8~`° o
o<doo°
N M O O
$$C~~ __
N
d
FSO
~ ° rn ~ a~

~ Y Q
s 5 5
A C C
LL _
d _
m
a
o ua c
~
~ ~ v d
p
N Olon
O
O e
{7 ~ O O
O
p
C N ri ~I
~ y~ ~ II
~
m II

~ y
J II
S
¢ S y
II

Z~ o n
La C
~ w
~N II
t~ ° d o 0
~i (n
m N j N
..
q. ~m
d O
I
OI
9 n n u
A n n 3
.~ ~
a U W N U
E~
~'~ro ~
~
`
`o
~
~~ ~d °
~
n 5' ~
U
°
a
a
01 H u ~
r.
I nl z~aaa >
3r~,~ s-rocz.~4, ~.
~~Pt,
88888888858888888588888888
~
N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
3 d
8888888°0°0°0888$8888°0°08°08888
n 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
3 ~'
8888888888SsssoooaooB~Sooo

~ oaooooooooaaoaoaooooooaooo
o
888880°88888888885°08888888$
~1 ~ O O O O O O O O O O O O O O O O O O O O O O O O O O
m ...
0 8 0 0 8 S S 0 8 0 S O S 8 S O S O S S 0 0 0 0 0 0
u
v 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
.~
R
8°0°0°0°0888°0°0880°888888°0888880°
3
d
N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
~

O y (~ y 1~ ~
8O 8088 ppNppS 1pp0 ~~upp1II I~ N 1~ pWp NIA S~~PyyI ~I~~yy ~~~+^+yyyy O'S aNa It)paNpappO
O 0 0 0 8~
~ S S
0
~ 0
~
0
rl O O
0
0 0 6 0 0
0
0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
~
p p p p p~
8 0 0 0 0 N N ('1 V N t0 h O~ M In I~ O O ((~~II 7 I^ O
0 0 0 0 0 0 0 0 0 0 ~ N N N N N
O O O O O O O O O O O O O O O O O O O O O O O C O O

88oo~NVmcVn~`°oBNlon
m~8°ad~ V ~mv
,
O O O O O O O C ~ .- N f7 V IA O t` tD O fV o7 N n Oi [7 10
~- ~ ~ ~ ~ ~ N N N
Q
~z
880800 000000 ~ 0000000 ~ ~ N ~.a-
0~
€ O O O O O O O O O O O O O O O O O O O G O 0 0 0 0 0
p p p p pp p p p p p p p p p
8 N 8 O O N o N O N 0 0 0 O O N O S 8 O 8 O O O 8 IA
41 5 O O ~ .- N N t'1 t`~ O V I(j If) fD 10 1~ f~ Cp ID pj pj O O ~ ~ N N

X
c
d
m
N
C
U

3
N N N N N N E j N N ~~~~ -~ ~~~~ •.• ~~~
A W W f
JJ
10 OD W
A
NN
O
O
~O
V
O
I Ol
t
O
V
N
P
A W W W
~
NN
~~
((
~~
((
((
((
~~
((
~~
(~~
(B~
J~~
p
((~~ pp (
(
J
O S~ S O S O O O S O S~ S O S O S O S O S O S
~
O O O O O O O O O O O O O O O O O O O O O O O O E
N N fJ IV IV IV IV IJ fJ
Oo Oo f0 f0 (0000000 C 00 tD f0 tO 000o JO10l fly fJ~
.'d O
~~

ttpp ttpp pppp JJ pp~~ 00~~ ((~~ {~~1 y.
~ Oo O
, tWJ O~ A ~ J
~ J A O V fJ 0
V W O
~W
I
~
~ t
NO
p
p
.
pp
~~
p
p
~
S N A S fAJ N~ tO0 O A fOJ 1W0 W V W~ W N v 0 (J Of ~ V

O
O .Y' 1pd
v
ppp OO
O p
O OOOOpOp~~ pOp~~ pO~(O~ O(O~ pOO AOA O(.O~ O WWO O
OmD Oi (ill f~.1 O OJO OJi (JJ ~ ~ Ol W S ~ ~ N f0 V A -A+ S S A ~ ry
00
0
0
0
0
0
0
00
0
00
0
0
OOOOO
0
OOO ~,~
p
pQ~
p
Q~
~Q
(~Q
p JJ
j(/
~(
~
j
~
N
j
Oi 8 ~ fWJO ()1 O A ~ ~D ~ ! ~ f0 00 N N N [OJ ~ ~ Ol OWO

O O O O O O O O O O O O
0 0 0 0 0 0 0 0
O
O O O A
~ A
p
p
p
S O O O O S S S S S S S O S S S S S S O S S S S

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a
~~
SSSSSSS°oSSSS88SSSSSS°oSSS
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
S °o S S S S S S S S S S S S S S S S S S °o S o° S
O
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 ~ °n ~ ~ ~ ~ ~ °o °m °m ~ °w ~ °v °v ° ° g i i S i S i ~

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 m
S S S S S S °o °o S S S S S S S S S S °o S °o S S S

O O O O O O O O O O O O O O O O O O O O O O O O A
~ N
S S O O O S O S S S S S S S S S S S O S O S S S

Calculate the stage-storage function for the detention system
Contour
feet
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
Stage
feet
0.00
Average
Rectangular Basin Contour Contour
Dimensions Area Area
Incremental Accumulated
Contour Contour Estimated
Volume Volume Stage
C C feet

0.00
24.6 24.6 0.27
61.6 86.1 0.77
19.1 105.3 0.91
54.2 159.5 1.29
44.7 204.2 1.59
47.9 252.1 1.90
38.3 290.4 2.13
28.7 319.1 2.31
0.31 0.38 0.19
0.63 1.33 0.85
0.94 1.62 1.47
1.25 2.45 2.04
1.56 3.14 2.80
1.88 3.88 3.51
2.19 4.47 4.17
2.50 4.91 4.69
KB = 117.3
b = 1.1957
Enter Ks and b values from the graph of storage vs. stage shown on the next page
Ks =Constant of power equation
b =Exponent of power equation
noo.oo
350.00
300.00
750.00
200.00
150.00
100.00
50.00
0.00
Storage vs. Stage
y = 117.3x"~~ ~
R~ = 0.9788
0.00 0.50 1.00 1.50 2.00 2.50 3.00
1 OF 1
7/19/2002

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ i^ ~ ~ ~ ~ ~
Circular Pipe Storage
Pipe size (ft)
Pipe Length (ft)
No. of Pipes:
Pipe area (sf):
stage d/D
0.3 0.125
0.6 0.250
0.9 0.375
1.3 0.500
1.6 0.625
1.9 0.750
2.2 0.875
2.5 1.000
2.5 No. of Manholes 0
65 Manhole Area (sf) 0.000
1 No. of Pipes: 0
4.909 Manhole Diameter (ft): 0
a/A Area Vol in Pipe Vol in Manhole Total Volume Incremental Volume
0.08 0.38 24.57 0.0 24.6 24.6
0.27 1.33 86.15 0.0 86.1 61.6
0.33 1.62 105.29 0.0 105.3 19.1
0.50 2.45 159.53 0.0 159.5 54.2
0.64 3.14 204.20 0.0 204.2 44.7
0.79 3.88 252.06 0.0 252.1 47.9
0.91 4.47 290.35 0.0 290.4 38.3
1.00 4.91 319.07 0.0 319.1 28.7

A
1
1
1
1
1
i
1
1
1
1
1
1
1
1
~~
APPENDIX C
r+~ ~rrr n i-.r n
r~~C, Z q
:.~.~~r/~sv~t
EXFrIrl PL
~r vEN - f~oo
.~YDROLDGJC CONTOUR S. D 2, o00
ORAINHGF ,9REA 35 Ac ~ 00
SMf~L L AREA f UL L BUSJN~ 55
ANSWER /,aoo
Q !O = 39 X /• 4 = 54. (o ~ F. 5. ~ . 8O° 4, 00
600
j ~~ 1
~ 8 -~ 200
4 ~ 20o T
v ~
v
a ~~E~_pcE ~Bo /oo
~ ~ ~ ~ ~ s ~o
,,
0 3 ,,,~.. ~ ~ ~~ 50
~ ~ ~~ ~
~ ~ _~
~ 2O ~ 3a
~ ~~ U
O ._ ._
~'• ~ ~ ~
V Q~ Q~ ~ ~ ~ w
o ~ Q~ ~o ~~ ~~ 5 ,~
~ ~ ~~ ~O ~Z ~`\
GURYE GORREE ON `' ~'~,
FOR DEVEL,OP~~NT ~`~
Ff/GTORS FD~Q FREQUENCIES 1 t
CURYE ~V/ALUE X ,:075
c~ ~23 ~~ n x 1.35
QIO~O u a X L-8~5
rr X L ~ ~
~PU/YDFf FRO~YI URBAN AREf~S
IvORTX Cf~ROLl/1rf~ s~r~ NIGHWRy con~M155IoN
clf~N, / ?.~ G 200 ~3

CHART C 200.3

RIDGE E
BRIDGE TECHNOLOGIES, LLC.
1 -800-344-21 02
~t~~
G.TZDS S ~ ~ 7 ~c.. k1 ~. f..I CJ ~.«-.4c~ a. ~ ~~ t~ ~ ~-~~;~, ~;a,c .d ~ p i ~ ~a~~"2,
Z . 3 ca-G'
J.. ~ ~.. ~._°~ c. ZS C.r~~..,~. • ~J rte, '..~~-. .
/ _ G
S " ~~~ '~~
'~
~ ~~
~ C>.CJ~-1u :1iz
U- `:,~~
Z
~~ = 5\~z -~ /~
~~ . „a ~^~
_. _ ~, z z icy ~,~
Q' GI A, ~ ~Ci,~~~~.22x2.3}= ~I,~CA C~S

Z ~ Year
~ K'

1
1
1
1
I
1
1
1
1
1
1
1
1
1
E~ Z ~ ~ P e: 2
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs :9.96 Flow depth (ft) = 0.69
slope Sin % : 4.8 Outlet velocity (fps) = 12.576
pipe diameter D in in.: 18
Manning number n :0.013
Pipe diameter (ft) 1.50
Outlet velocity (fps) 12.58
Apron length (ft) 9.00
AVG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
» 6 B 22 «
13 Bor1 22
23 2 27

JOB NO.
Soil & Environmental Consultants, PA SHEET OF
l (OIO Raven Ridge Road Raleigh, North Cazolina 27614 Phone: [phone] Faz: [phone] DATE
www.SandEC.com
JOB NAME
S U BJ ECT_
BY
'•'- -*--
' 1 ~ _.__.. ~. ___. I __
_.. t.._.,. ___t. .__.. ~.._ ~. .. ~...__ _ _ _ .~__ __ ___ ___ ___ _ _ _ ___ _.__ __
...
.,
., ,
....---~
,.
..;..
. .. ...
. ~-- -.----r- ----._. . ~ - ---- -- --- --- - - -- - ---- - - - - --- - -- --- - ----- - - -- - ---
.~ --
,-
. ;
,~ -- ;_
. -----~
. ..
}
.~,
~~ ; -
~-
..
;:
..,
. {...
....
.-
- --:
. .
.,
. ,
,.,
. - -~~
r
.~
'--
~. , -, - - -- - --- - ~ - -- -H ;--.- - ----
~~~
,__.. ,. ,
._
--
-¢4'
,.
,,
..
__
._;.
.. { - .E
__ ..;
..
. ----~
{
- --
~~
,
"~
......__
__ __ __
~ ~ :. ..~.
I ,
t-.-1-__~__._.~.......__ ~_.. _._.__._____ _ __ ___ _ _ _ _ __ _ _ __ ... ._.__ _ _ _ _ ._
_.
1
--•
.,
~,~v Diu aFPr~opa~~--- .3.~, ,.~~.. iRo~. ~~_.
__
_;
.,
~tP
_._~
. - - ,--
- .- -
-~~-
. .
,.
. , --`
, ,
,.
. 4 ~ ~-- -... _ . - -- -- ...- -- -- - -- - ----• --- - - ---
. ~ -~ _
. ~ _
..
. ~ ~ ~T. Fi9 Gc~A"~25
. , .a.. .
F~
_-
-- .-- -.- R- -.-- , - .- . - -~ - . - - ---.-- -~ - -- - - - - -~ ~ s~~' ~
-: -
,.
.,
._ ...•
..~
.. , t .{ .i.. {_
.~..
- ~ ~~
I I
_. ,.._~
r~-
~I
`~--t---~_. ... ._ .~
~ ~/
,~ ... .
~' _ -- -. -
.. ,.
-.---
..
.. _ ,_
T~~ - - ~~
. ~:
.,.
----
. --
,,
-,N
....
. ~ t..
~~
..--
,~,
. -{-- ~-
---~
-,~- , -
. ~ -
._ _
-- -- a----;--- - - - ~-~;~-;~,~_ --- -
-~ '----1
.,
,~ _
.~
. ~ .
.:_
t
--~ ,
~..
{.
I
-i
__ .F.-.{. _._..~.
.__._...
_.r__._.
... .-
;_.
--
~._._t____.._...~._._.._._ ~ ..____ __ ___ ___ _ _ _ __ __... _ ___ ___ ._ ___ _ _. _ ._ _____ _. _ __ _ _ ._ ____ _. __ __._ _ _
~. .~
,. f.. y..
-t-
~; ~,
,.. __ _
.~ .
..
...... .,
.,.. ,..
'"'
I
~-
..
.:
..
;.
.. .,
,, ;
,.,,
.,, ;
....;.
,..~-:
,, ., ;~
...
.. ~ ,
_,. ;
.: -~
- --~---
~- -
-~ ~-
I
.._
_ .....
...
...
t-
i - 'i-- -i-- -t- -i° t
--t
..
=-
~ ~ I
I
I I
I
,.. _..
.. 1 .
_ _t...
..
-
i--. .:
" . -
'.
--•-

t

NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 72 Flow depth (ft) = 2.33
slope S in % : 1.3 Outlet velocity (fps) = 12.240
pipe diameter D in in.: 36
Manning number n :0.013
Pipe diameter (ft) 3.00
Outlet velocity (fps) 12.24
Apron length (ft) 24.00
AVG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
6 B 22
» 13 Bor1 22
23 2 27

t
w
i

t-'i ~ E.. e4 A : -7.
APPENDIX C
SHEET 3 OF 8
E YFr~'-~I PL c
~ r vEN :
.~YDROLC3GJC CONTOUR 5.0
MHL LN AREA fU~ L BUSINE55
S INER
Q10= 39 X /4 = 54.(0 F.S.
8
v~~ ~
p -1E,~gM'°LE
4 ~~ 1` --
3 ~~\ ~' ~ ~
~~ 1
D ~`~
~ ~
~ ~,
~ `~.,-.
`~/.0 --
o -- --
0.5
V ~ ~ ~ ~
w ~w W~ w ~~
~~ w~ ~~
V
~ ~~ ~~ ~ ~~
~~ 4 ~_
FOR v DE~ELOP~ENT
~` 2- ~ ~ ~m~ ~'a~ i' ~/
7, 000
~aoo
800
600
~~
200
X80
~- (00
~~ ~
20
V
~o ~
8. tr
/o
4
2

fi9GTOR5 FO/~ FREQUE/VClES
~Q ~ CURYE YRLUE X /: Q75
G~$$ZO ~r n X /.35
QlD~O rr R X ~•8~
n X ~!
~~oo
boo
ago
J..
--~ 200
t
goo
50 ~
~j0 ,y
Zo
-l4
- ~
-5
P
~PUNOFF FRO/1~ URBAN AREF~S
IvORTt! CRROLI/YA s~rF NlGHlr1/RY co/r~M1551oN
J/9N, / ?.~ G 200.3
~~c~ ..
C - ~ ` ~~ ~~ `"!
CHART C 200.3
~_ ~ ~ ~:-,

1 ~,~~. ~

Exhibit 11
`~ ~~~~~ O
Iso lo,ooo
16e e,000 EXAMPLE ~ ~) l2) (3)

136
5000 D•4Y IneMs (3.~ feet)
s~ooo u•IYO ~t. 6.

~
~~

144 .

4,000 ~ a~ nw 6. s.
132 o tees
3,000
s.
4
(1) Y.s e.e 4,
120 (2) Y.I 7.4
000
2 4 _
,
(3) Y.Y 7.7 . 3
loe
eD In feet •
3'
96 1 000 3'
800
--
-•
--
64 600 ~ 2' 2
/
600
72 400 / e 2.
300 6~~ . _ _~ .- __ --~.'S ,`~Cl> ~~
z ~ / ~
~
= 60 v 200 / ~ (,s
Z / W
d / _ ~~~;,.__

~
/ W
100 c"
= ~~
J 4e / ~ eo

a x
v /Q V 60 __ _ _
60
A
ENT
E I W
° L0 I.0
~ 0 R
NC
.I-
HW SCALE
40 p
~ 10
,
TYPE _
W
~'
W 36
30 _
(I )' Swore edge wltA
3 .9
.9
Headwall .9

~
33 _

'
C
Q
20 ~
; Groere end wire
(2) Q
W
C 30 ' Madwall = .8 .8
(3) Groove end •e
2T pre)eetinq
~
!
% - --------___..___
10 - ___ __
~ r
S ~ .~T•'t ,i r ~
2y
. z .
8 To uee Beale (2) or (3) pre(eet
- 2 1 5 Aorltontollr to Boole (I),tAen
4 uee etrolgM Inclined Ilne tArougA
~
~ 0 and 0 sealee, or rereree oe
'g
6
~~ 3 illuetrofed.
.
18
2
15
.s

'3 .~
t.0
12 HEADWATER DEPTH FOR
CONCRE TE PIPE CULVERTS
HEADWATER SCALES gas
REVISED MAY 1964 WITH INLET CONTROL (,~_~, -~
9UREAU Oi -UeIIC ROAD ! JAIL If f!

E 1 ~,.~ I . ~_ ! ~ , ~
~~

s
r
r
i
i
d
N
8
A
a
E
d

s
s
8.
R
g E
ui
f F
g
8
8

0 0 0 0
~ R N o
~ o
~ g o
(4~) Mold
J ~
a~~
m
pl ~ r
C N
2
m 0
P~
w` ~ y a~
~ ~

O
v~~ LL
L ~ C
C ~ _
m~ _00
O N
o~o$~~
O' t7 O (D O oo~0
~ N O~
M 000
~^ t7
m $$g
0 0 0
t
II ~ `
N II II II II yyII ~ II m ~ `I II II II
R Z ~~ N O U O Z O U S 3 J N U 3 J N U
..~
LL LL m d LL~
t~ m ~ v U ~
°o o~~o ~i
O N OI O O I h
S M N
O
C
_ N ~_
ttl O ~ ~ yJ rJ
~ ~ y ~ LL C C
$a o mm U E.~
~1 N S N pp~~ S S
g O N O N M I yys pi ..
~ N J S ~ ~ ~ II ~ IpI
as n 01 0 0
5 ~ ° 3 ~y~mb~in
~win0
~~.~m~~ ~ u u u ~u n 31I E~~'~`~~ ~
tLiaaoOl= ~d~°ro ~~nn°i SF3 Uzf aaa >o
SSS88888SSS88888588$S888S8
N 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
$8$8S8So88oo8888$S8$g8S888
`~
3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
88888888888 °oS88oooooob"b'b"`3o

O~ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o c c o o d o 0

SSBSS°o°o°oS°o °o8S88888888S888S
o 0 0 0 0 0 0 0 o G o 0 0 0 0 0 0 o G G o 0 0 0 0 0
~~
p p p p p p po p p p p p p p
S S S S S S S S S S S S
S S S S S S S O S S S S S
O
o
d
p
r~ o
d d d d o 0 0 0 0 o d o 0 0 o d d d d d o o d

oooao$ooooooooo$$ogSo$g$go
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
~~
~
_
Q
S S S S O S S S S S 0 0 0 6 S 0 0 0 0 0 0 0 0 0 0 0
p~ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
~t
O
S 8 8 S S S o 0 0~ o 0 8~ `~ o S o 8 S°

S S O O~ N 10f) W N S V~ f7 V m N W aD ~ O V O~1 ~ I~ 10 ~
O O O O G G O O ~ ~ fV f`7 •t In 10 fU ~ ~ ("1 tG CG O Pl ((pp ~ (y
N N N N W

S S S S 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0^ N^ l7 <
30 ~ O O O O O O O O O O O O O O O G O O O O O G O 0 0 0
p p o o p pp oo pp p pp p
SI~SIASSS VISSSS~S~(1S NSIASNS~f1S IASN
C O O ~ ~ IV (V t7 b) V sf N N tD t0 t` n a0 OD Oi Gj O G ' ~ (V (V
~~ ~~
t-~
J
X
N
t
U

E X
N
N S
n Ut A A O
W
0 0 t
o
O]
V O
I 0 (
0
f0 O
J
A
A f
J (
J N N W
{1~
11
11~
(
1~
~
NN
NN
yy
~~
N
O S O S O O O S O S O S O S O S O S O S O S O S

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
O) O) 101010000000 00010 1010 O) O) J 010 (n N

N N N~ ~ O O O S N 0OD f0J 1J0 N O N OD A O T N 1.WD
P O J W !D N
O O
J
1pp pp p ~p A (~ y~
1
(
p
IOD fA/l fO/1
J0 0
(/l
N
A S
A
N
A ~ 100 A 1N11 ONi 01 10 1Ji1 111 WW t
1
A
A
WW
(
(p
~~
W~
~~
p
~
p
~
Obi S S S S OWi ~ S S 01 S Q! fD f0 0 f0 ~ S f0 fS0 fD ,fSO ,fSO 1SD
0 f0 f0 !O f0
f0 10 l0 f
0 f0 !0 X11000 10 l0 f ~ N
A
NN
(~
lJ N -A+ O 100 OOD V m S W N~ O 1N0 ~ 0 N A N~ O 10 O) T
O
1Q~
O
O
O O
0 0 0 0 0 0
O
O
O
O O O
O
O
O O O
O
O
O V
p
p
p
pp
pp
pp
p
p p
p p
p p
p
p p
p
OV V ~ 01 01 0~ OOi 0Oi 0Oi 01 O~ V0i 1011 N (011 fOl1 N A A A A A fOJ 1OJ
N
N
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
S S S S S S S S S S S S O O S S S S S S S S S S ~

~ 9
N
,7
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
S S S S O O O S S S S S S S S S S S S O O S S O `-'
0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
S S S S S S S S S S S S S S S S S S S S S S S S
0
O
O
O O
0 0 0 0 0 0 0
O
O
O
O O O O O O
O
O O O
p
p
p pp
p
p
p
p p
p
p
O O J 0 S S S S 001 OI 001 fOtl (O/l 1011 (011 1011 N A A A A A W 1OJ

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 `~ ~
S S O O O O S S S S S S S S S S S O S S S S S S
l~
1~'
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N
8$888$$S8$8$S$$SS$S$$8$$

1
1
1
1
1
1
1
1
1
Calculate the stage-storage (unction for the detention system

Contour

Stage
Rectangular Basin
Dimensions
Contour
Area Average
Contour
Area Incremental
Contour
Volume Accumulated
Contour
Volume
Estimated
Stage
feet feet Len th ft Width ft SF SF C C feet
0.00 0.00 15.00 15.00 225.00 0.00
0.25 0.25 15.08 15.08 227.41 226.20 56.55 56.55 0.23
0.50 0.50 15.16 15.16 229.83 228.62 114.31 170.86 0.53
0.75 0.75 15.25 15.25 232.56 231.19 173.40 287.70 0.79
1.00 1.00 15.33 15.33 235.01 233.79 233.79 407.18 1.03
1.25 1.25 15.41 15.41 237.47 236.24 295.30 529.08 1.26
1.50 1.50 15.60 15.50 240.25 238.86 358.29 653.59 1.48
1.75 1.75 15.58 15.58 242.74 241.49 422.61 780.90 1.70
2,00 2.00 15.66 15.66 245.24 243.99 487.97 910.59 1.91
tCa = 399.24
b = 1.3139
Enter Ks and b values from the graph of storage vs. stage shown on the next page
Ks =Constant of power equation
b =Exponent of power equation
1200.00
1000.00
800.00
800.00
400.00
200.00
0.00
Storage vs. Stage
iaiaa ~
y = 369.24x
RZ = 0.9946
0.00 0.50 -- 1.00 1.50 2.00 2.50
1 OF 1
7/12/2002

i ENGINEERING CALCULATION SHEET

CLIENT SUBJECT
PROJECT No.

G'~ASS fir- ~ i't - G +"~ i ~ r h t Ste' ~ ~ ~, ~... ~-~
A2~ = Z.3 ~c
o
~- ~~~

~1/ ~ S ~ i ~ Z~J `Jo
~ ~
~, ~~~
~ fa,<;"a~~
i~ C~ k ~~ ~ ~ ~--~,5
L~~

~.a~,
~,~
~~ l ~ L,/ ~ Q ( t J
1
1 ~-
r
PAGE OF
Prepared By Date
Reviewed By Date

~D 5
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
the expected outlet velocity and depth of flow in a
pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
flow Q in cfs : 11 Flow depth (ft) = 0.92
slope S in % :1.25 Outlet velocity (fps) = 7.785
pipe diameter D in in.: 24
Manning number n :0.013
NRCD Land Quality Section
NYDOT Dissipator Design Results

Pipe diameter (ft) 2.00
Outlet velocity (fps) 7.78
Apron length (ft) 12.00
AVG DIAM
(inched
STONE
CLASS
A
B
Bor1
2
THICKNESS
(inches)
3
» 6
13
23
9
22 «
22
27
-- Dissipator ,Pipe or Quit (D P or Q) --

Level Spreaders
~~ from Erosion and Sediment Control Design Manual

r

1

Minimum Dimensions for Level Spreader
Q cfs) Entrance Width De th End Width Len th
0-10 10 0.5 3 10
10 20 16 0.6 3 20
20-30 24 0.7 3 30
Pie Q Min Len th Des Len th Min De th Des De th
1 23 30 75 0.7 0.75
2 9.96 10 50 0.5 0.75
6 11.3 20 25 0.6 0.75
9 11 20 40 0.6 0.6

ENGINEERING AL CATION SHEET
,_ C CU
CLIENT SUBJECT
' PROJECT No.
,~ ~... ~..~: ~.~ !~' E ~~.~' ~,,Ca~, lam. n..~ ~
C =' ~~ r ~.
~~
t-~ ~ ~ `~; `"` ~ ~u.
~~
yea (.~, ::~~ ~,: C.,s, ~ ~ ..~ _ra ,~^~'.a~~
vin = 3
~aN rt ~~ d

' ~~~, r~ t. i. ' '., ~ ..,.... ~ C-~ Z c... ...
` `/ ~
r
~,
CnC~- .~
Prepared By
Reviewed By
a~
PAGE OF
Date
Date

ENGINEERING CALCULATION SHEET
CLIENT .SUBJECT
PROJECT No.
3q ~ ca cy -r® ~~ --c5c~
Prepared By
Reviewed By
PAGE OF
Date
Date
G? = C I p
~ . ~, ~
~~,. ` 1 ~ ~ 2 ca. ~.
~' (~, ~ , i;,n ,~ ~ ado ~ ~ ~ ~. ~~' I ~ `~ ~ ~.
' S . 2,'S r_ ~4. ~
t_
~~ ~ ~
- ~ , ~. ~'~~,, `, ~ ~• ~ ~~ ~~,~ ~~:?.~ t~~ ~ Ear ~.,;? `~~r ~.. t:`• ~ t~ `ik .:~ .a t-~,,~ Gtr: ct ~.,~.
4~, `~
l~lS Er ICE. U pit ti+. ~.c ,~ ~,1 `~ 1..1 r~l ~,,
Y ~ ~ '~, l ~ ; ".K;+ ~ ~, ~ <a ,) V ~ ~.~ ~ ,rl. E ~C,;,1. t~ %'a.: l:a ~,..~ fir.
'~
i
1
i
1
1
1

EC-DESIGN(R) 2000 Channel Analysis Report
Proiect Information
Pro.lect Name: Park at Langston Last Update: 6/20/2002 3:36:31 PM
Description:
Notes:
Units: English
Nearest City:
Channel Design
Channel Name: Henderson Rd Sta 39+00 - 44+00 Units: English Design life: 300 months

Desi¢n Criteria Vegetation and Soil Channel Geometry Flow/VelocitY
Flow Rate (Q) Vegetated Yes Bed Slope (ft/ft) 0.062 Discharge (cf/s) 5.250
Vegetation Class D Req. Freeboard (ft) 0.000 Flow Duration (hrs) 0.500
Soil Filled No Avg. Velocity (ft/s) 2.870
Channel Length (ft) 500.000

Channel Side Slopes Channel Bend No
Bottom Width (ft) 0.010
Left (H:1 V) 3.000 Bend Radius (ft) 0.000 Required Factor 1.00
Channel Depth (ft) 1.000 of Safety
Right (H:1 V) 3.000 Outside Bend
1
-DESIGN(R) 2000 6/20/2002

ENGINEERING

~~ CALCULATION SHEET PAGE OF

CLIENT B E
__ SU J CT
Prepared By Date

PROJECT No. _____ Reviewed By Date
'
' /~Lt~F1,q~e.(C~oa:~, 1 Z -l5 ~ - 15 1 ~S Lt.Fr 5~.~~. d~t~.s/

'~'
< <~ , <
~.

Q~ ~.~ ~~S

~= 3
~y ~
~, = Co , 3 I ~o

\~
,f
r
P JJ
1

Z~ ?_G'. ~

EC-DESIGN(R) 2000 Channel Analysis Report
Protect Information
Protect Name: Park at Langston Last Update: 6/20/2002 4:17:06 PM
Description: Units: Eng lish
Nearest City:
Notes:

Channel Design
Channel Name: Alphawood 12+50 - 15+75 Units: English Desi¢n life: 300 months

Design Criteria Vegetation and Soil Channel Geometry Flow/Velocity
Flow Rate (Q) Vegetated Yes Bed Slope (ft/ft) 0.063 Discharge (cf/s) 2.600
Vegetation Class D Req. Freeboard (ft) 0.000 Flow Duration (hrs) 0.500
Soil Filled No Avg. Velocity (ft/s) 2.190
Channel Length (ft) 325.000

Channel Side Slopes Channel Bend No
Bottom Width (ft) 0.010
Left (H:1 V) 3.000 Bend Radius (ft) 0.000
Channel Depth (ft)
1
000 Required Factor 1.00
. of Safety
Right (H:1 V) 3.000 Outside Bend
Results
Veloci ft/s Shear Stress bs/s ft

Lining Materials
Com uted Max
Allowed Safety
F t
Com uted Max
wed Safety
Factor
Left LANDLOK TRM 435 2.280 18.000 7.890 2.880 5.000 1.740
Bottom LANDLOK TRM 435 2.110 18.000 8.530 2.470 5.000 2.020
Right LANDLOK TRM 435 2.280 18.000 7.890 2.880 5.000 1.740
Calculation Results:
Flow Depth (ft)
Flow Area (ft)
Hydraulic Radius (ft)
Composite 'n'
0.630 Left Wetted Perimeter (ft)
1.190 Bottom Wetted Perimeter (ft)
Right Wetted Perimeter (ft)
Total Wetted Perimeter (ft)
0.300
0.0792
Avg. Velocity (fds)
Avg. Discharge (cf/s)
1.980
0.020
1.980
3.980
2.190
2.600
Avg. Flow
Depth (ft)
0.630
DESIGN(R) 2000 6/20/2002

ENGINEERING CALCULATION SHEET
CLIENT SUBJECT
PROJECT No. __
G C.a , ~:..!~
1 - ~~.~..s t,
G?~ i,v~ ~~'s
~-, = 3
~, S - 15 ,~~c1a
,,~.
_ ...~ ~ ,
~.~
r
PAGE OF
Prepared By
Reviewed By
Date
Date
~:''~

ENGINEERING CALCULATION SHEET
CLIENT SUBJECT
' PROJECT No, ___
~- ~~~. ~ ~
'~~ '~~U c'~S
1
!~
`~;
ll
r
t
i
Prepared By
Reviewed By
PAG E
OF
Date
.Date

EC-DESIGN(R) 2000 Channel Analysis Report
Proiect Information
Protect Name: Park at Langston Last Update: 6/20/2002 3:59:33 PM
Description: Units: Eng lish
Nearest City:
Notes:

Channel Design
Channel Name: Tributary Units: English Design life: 300 months

Design Criteria Vegetation and Soil Channel Geometry FlowNelocity
Flow Rate (Q) Vegetated Yes Bed Slope (ft/ft) 0.080 Discharge (cf/s) 3.000
Vegetation Class D Req. Freeboard (ft) 0.000 Flow Duration (hrs) 0.500
Soil Filled No Avg. Velocity (ft/s) 2.590
Channel Length (ft) 300.000

Channel Side Slopes Channel Bend No
Bottom Width (ft) 0.010
Left (H:1 V) 3.000 Bend Radius (ft) 0.000 Required Factor 1.00
Channel Depth (ft) 1.000 of Safety
Right (H:i V) 3.000 Outside Bend

-DESIGN(R) 2000 6/20/2002

ENGINEERING CALCULATION SHEET
CLIENT SUBJECT
PROJECT No.
C~ I I
F,~1 ~ ~ ~.

~' r , ~ ~.~a. ~~

~.,
~- & . ~ `-t e S 5

\~I~~n ~.~tii

w

PAGE OF
Prepared By Date
Reviewed By Date
,,
+i~
Gd ~ o:~''
i .y 1 '!•
~ J
~U,Co~Cd~~n~~~ C~~,~
1
,R `
~.
'_
r

' ENGINEERING CALCULATION SHEET
PAGE OF
r
CLIENT _._ _ SUBJECT Prepared By Date
PROJECT No. __ _ Reviewed By Date
p . ~;~ J ~~
G= ~.w
..,
~ ~ ~~
/ /•~ , ~
Cv ~~~ ..~ ~ ~f `~(~ e`"~tiJ 1
VI~~~ ~ . ~ 1 G~ S
Gw ~..v~ ~ ~~'e~2 ~t~E ~2 ~v~s ~i ~..k..
. 1
Q = C ~,,.,, lr ~ s ~-~
,,:?
G~..,~~V'~ d -. ~, F. t+x, ~ ~. e.74.d Da.""C i f rt~ ~
'i.:a~
~.
'' + p , C.a
~, ~, ~ ~'
n, ~ ~ ~'-
. , ~ f ^/~
.~~~~ - r ~a 1 ~:~ ~ Ga_S1~1e~c.~-~C6.c; ~ ~..9~d~
~,.:~ - ~ , 5 c~
""
'~-~.
~ = ~ t.... -..-
~ ~ _.
''~ _... Z ~.~ ... x,l ., ~ 5
1
~,~ ~ - '~ r , mac. ~ ~ ~..1 ~, ~ 5 /` ~.I ~, ~ c~ ~~~ - ~ ~ !~ v ~ S I a r t-4 k t~ i)

ENGINEERING CALCULATION SHEET
CLIENT _ __ SUBJECT __ ___.__.__
PROJECT No.
~~ I
~~ ~ ~ j~
~~,~ l:~G ~~ ~ ~,~ 4
., 3~~
r~ ~ ~ '~~~~~ I... l~
~~,~~
i,m ~:!
'y ~ ~ .,. h~ ~ , .~.
~....,;rq5 ,., ~ . , ~F
Prepared By
Reviewed By
PAGE OF
Date
Date
G'~. ~ ~`tC.~ l:.C~A~
~ t,~,~
~'.c.1 ~ a, ~o
~ 1 ; , ~'w ~ '' ,;;~.4

i~'~ K p ~
_ YI ~ ,:,Y
`;w.\ ~yJ i 4~.
~~.~~ .,, ~. ~~,..~ r.. _
G~ ~-]
,..- ..W Utz
r
~ _
t
r

' ENGINEERING CALCULATION SHEET
CLIENT SUBJECT _
PROJECT No. _ _
C-~~ ~
Prepared By
Reviewed By
PAGE OF
Date
Date

A = v. 2S a. e
r G. o'
«.

~(~ Z.J ~i„ ~.. .. ~ („~ . .t: i.~
C.~', ~, ~ , C~ ~ c~ 5

C{~~.GIL ~ ~'C~T2 V.,~~ljt ~ ~,R I t~l ~ 'e,

~'
~;
~
. G
a

'3/Z y
.~
,
.
4.
~,~
f•
..r) ~ ~h .a ~ ..
r
F
~ I
~
C~~ ~
, ~~ ~ ~
'~
~ 2 Z
1~.~ ~ ~
I I d a
4 .a ~
O 3
y
»+a.,e
~ ~.~,
~
< 3 ~.-
~
^
, :

r

' ENGINEERING CALCULATION SHEET
i_
CLIENT
' PROJECT No.
SUBJECT
Q ~ l - . C~ r..,,.4 ,..
1

~c.l ~ ~ ~z ~., ~ r. ~
~ ~ ~ -~_a~., ,_~~ ~~~~.
:~

~-~ , a ~ ~~~.~

c~ .~ , ~~ w
PAGE OF
Prepared By Date
Reviewed By Date
Cad' ~ % i t... 1~.. t.:: C~ ~, f
~' u, v , c.p ~".'
.~,
A ~
1 _ `' ~ ~~
1 ~ ....~~ ~ ~' ~ z ~~_ ..~_ --~, ,~ a , ~-

~, s
~

Itil i l,.l- ~ ~ "(" ~ r;,
~~,,~ a~~ 1 ~=t c ~, ; , ,_ ~." o, ~ ~ I~ sLa~ is 7'

i
Channel Design
Date: 7/15/2002
Designer: CEK
Project: Park at Langston
Channel Location: Relocation at Blue Needle
Q10 = 71.5 cfs
m = 4 :1
slope = 0.038 ft/ft
lining grass
Maximum Permissible Velocity = 4.5 fps
n = 0.03
compute best hydraulic section
k = 0.246
y = 1.461 8.929202 3.249681
Best Hydraulic Section
Depth = 1.46 ft
Bottom Width = 0.36 ft
Velocity of BHS:
Wetted Area = 9.06 sq ft
Velocity = 7.89 fps
Velocity Too High
If BHS and Velocity are ok, use this design. Else continue to Velcity limited procedure
Area = 15.89 sq ft
W 1 = -4.25
W 2 = 50.142961
Depth of Flow = 0.33 ft
Bottom Width = 47.46 ft
If channel section is ok, use this design. Else continue to Depth limited procedure
Bottom width = 3 ft
Depth of Flow = 1.2 ft
m = 4 :1
Depth of Channel = 1.7
Velocity = 7.6 fps Velcoity is Too High! Use permanent liner
Area = 9.36
Wetted Perimeter = 12.90
Hydraulic Radius = 0.73
Zreq = 7.38
Zav = 7.558848 Depth is too high
Adjust values for Bottom Width, Depth of Flow, and m to make Zreq =Zav

Channel Design
Date: 7/15/2002
Designer: CEK
Project: Park at Langston
Channel Location: Trapezoidal Ditch 1 -Lots 11-12
Drainage Area = 0.5 ac
Q10 = 21.7 cfs
m= 3:1
slope = 0.0211 ft/ft
lining grass
Maximum Permissible Velocity = 4.5 fps
n = 0.03
Length = 280 ft.
best hydraulic section
k = 0.325
y = 1.144 2.302064 1.609246
Best Hydraulic Section
Depth = 1.14 ft
Bottom Width = 0.37 ft
Velocity of BHS:
Wetted Area = 4.35 sq ft
Velocity = 4.99 fps Velocity Too High
If BHS and Velocity are ok, use this design. Else continue to Velcity limited procedure
Velocity Limited
Area = 4.82 sq'ft
W 1 = -3.32
W 2 = 9.7889883
Depth of Flow = 0.63 ft
Bottom Width = 5.83 ft
If channel section is ok, use this design. Else continue to Normal Depth procedure
Normal Depth
Bottom width = 3 ft
Depth of Flow = 0.82 ft
m= 3:1
Depth of Channel = 1.5 ft
Velocity = 4.8 fps Velcoity is Too High! Use permanent liner
Area = 4.4772 sf
Wetted Perimeter = 8.19 ft
Hydraulic Radius = 0.55 ft
Zreq = 3.01
Zav = 2.994 Depth is too low
Adjust values for Bottom Width, Depth of Flow, and m to make Zreq =Zav

Channel Design
Date: 7/15/2002
Designer: CEK
Project: Park at Langston
Channel Location: Trapezoidal Ditch 1 -Lots 12-13
Drainage Area = 3 ac
Q10 = 19.5 cfs
m= 3:1
slope = 0.0175 fUft
lining grass
Maximum Permissible Velocity = 4.5 fps
n = 0.03
Length = 190 ft.
best hydraulic section
k = 0.325
y = 1.138 2.068675 1.465549
Best Hydraulic Section
Depth = 1.14 ft
Bottom Width = 0.37 ft
Velocity of BHS:
Wetted Area = 4.31 sq ft
Velocity = 4.53 fps Velocity Too High
If BHS and Velocity are ok, use this design. Else continue to Velcity limited procedure
Velocity Limited
Area = 4.33 sq ft
W 1 = -3.32
W2 = 7.6450333
Depth of Flow = 1.01 ft
Bottom Width = 1.23 ft
If channel section is ok, use this design. Else continue to Normal Depth procedure
Normal Depth
Bottom width = 3 ft
Depth of Flow = 0.8 ft
m = 3 :1
Depth of Channel = 1.5 ft
Velocity = 4.5 fps Velocity is Too High! Use permanent liner
Area = 4.32 sf
Wetted Perimeter = 8.06 ft
Hydraulic Radius = 0.54 ft
Zreq = 2.97
Zav = 2.850 Depth is too low
Adjust values for Bottom Width, Depth of Flow, and m to make Zreq =Zav

Channel Design
Date: 7/15/2002
Designer: CEK
Project: Park at Langston
Channel Location: Trapezoidal Ditch 1 -Lots 13-14
Drainage Area = 1.25 ac
010= 5.5 cfs
m = 3 :1
slope = 0.0211 ft/ft
lining grass
Maximum Permissible Velocity = 4.5 fps
n = 0.03
Length = 300 ft.
best hydraulic section
k = 0.325
y = 0.684 0.583473 1.609246
Best Hydraulic Section
Depth = 0.68 ft
Bottom Width = 0.22 ft
Velocity of BHS:
Wetted Area = 1.55 sq ft
Velocity = 3.54 fps Velocity OK
If BHS and Velocity are ok, use this design. Else continue to Velcity limited procedure
Veloclt~ Limited
Area = 1.22 sq ft
W 1 = -3.32
W 2 = 2.48108
Depth of Flow = #NUM! ft
Bottom Width = #NUM! ft
If channel section is ok, use this design. Else continue to Normal Depth procedure
Normal Depth
Bottom width = 4 ft
Depth of Flow = 0.35 ft
m = 3 :1
Depth of Channel = 1 ft
Velocity = 3.1 fps OK
Area = 1.7675 sf
Wetted Perimeter = 6.21 ft
Hydraulic Radius = 0.28 ft
Zreq = 0.76
Zav = 0.764 Depth is too high
Adjust values for Bottom Width, Depth of Flow, and m to make Zreq =Zav

Channel Design
Date: 7/15/2002
Designer: CEK
Project: Park at Langston
Channel Location: Trapezoidal Ditch 1 -Lots 23-25
Drainage Area = 1.2 ac
Q10 = 5.2 cfs
m= 3:1
slope = 0.0175 ft/ft
lining grass
Maximum Permissible Velocity = 4.5 fps
n = 0.03
Length = 375 ft.
best hydraulic section
k = 0.325
y = 0.693 0.551647 1.465549
Best Hydraulic Section
Depth = 0.69 ft
Bottom Width = 0.22 ft
Velocity of BHS:
Wetted Area = 1.60 sq ft
Velocity = 3.25 fps Velocity OK
If BHS and Velocity are ok, use this design. Else continue to Velcity limited procedure
Velocity Limited
. Area = 1.16 sq ft
W 1 = -3.32
W 2 = 2.0386756
Depth of Flow = #NUM! ft
Bottom Width = #NUM! ft
If channel section is ok, use this design. Else continue to Normal Depth procedure
Normal Depth
Bottom width = 4 ft
Depth of Flow = 0.35 ft
m= 3:1
Depth of Channel = 1 ft
Velocity = 2.9 fps OK
Area = 1.7675 sf
Wetted Perimeter = 6.21 ft
Hydraulic Radius = 0.28 ft
Zreq = 0.79
Zav = 0.764 Depth is too low
Adjust values for Bottom Width, Depth of Flow, and m to make Zreq =Zav

5 - 1" DIAMETER WEEPHOLES
3.~~
~ ~
f~~ ------~ 0.75'
3.
t"~ i nl
~ SEE ~,~s )
2 - 6" RAILROAD TIES
1" DIAMETER WEEPHOLES
NTS
GRASS SWALE WITH
TIMBER CHECK DAM
GRAVEL C~S~ >'~~ ~

Sediment Trap Sizing
(Re/erence: NC Sediment and Erosion Control Manual)
' Protect and Project Number =Park at Langston
Sediment Trap ID = 1
Location of Sediment Trap =
'
1)ra~na_ge Area description to sediment Trap
Disturbed earth (this project) = 0.60 AC C~ c= 0.50
Undisturbed, wooded areas = 1.40 AC C~ c= 0.20
Undisturbed, grassy areas = 0.00 AC C~ c= 0.35
Other areas = 0.00 AC C~3 c= 0.60
' Total = 2.00 AC @ c= 0.29
,Required design aspects of sediment trap
' Required sediment volume of trap =_>
The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
' Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
Sediment storage required = 1080 CF
' Kev aspects of sediment trap as designed
' Design dimensions for sediment trap based on required sediment storage amount =_>
Sediment storage depth needed - 3.0 ft
Surface area required = 360 SF
' Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 15.00 ft (measured at bottom of trap)
' Sediment trap width = 30.00 ft (measured at bottom of trap)
Surface area provided = 450.00 SF OK
' Sediment storage volume provided = 1350.00 CF
Sediment trap required dimensioning for flood passage =_>
' "Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
'`' Pass Q10 over rip-rap weir with 0.50 foot minimum freeboard
"` Max. depth of flow over weir = 1.0 foot
' Length of spillway required (max. depth of flow = 1.0 ft.) __>
' Regional ten year storm intensity, 110 = 7.22 in/hr

Q10 =
Weir length =
Depth of flow for this weir length =
Resultant depth to top of berm =
Final mfnimum dimensions for sediment trap

4.19 cfs
10.0 ft
0.27 ft
4.27 ft
OK
Depth to top of berm = 4.3 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 15 feet
Length = 30 feet
Len th of Weir = 10.0 feet minimum
Note: Sediment trap dimensions given (length and width) are dimensions for
the bottom of the sediment trap.
I

Sediment Trap Sizing
(Reference: NC Sediment and Erosion Confro/ Manual)
' Protect and Protect Number = Park at Langston
Sediment Trap ID = 2
Location of Sediment Trap =
' Drainage Ares description to sediment crap
Disturbed earth (this protect) = 0.50 AC ~ c= 0.50
Undisturbed, wooded areas = 0.00 AC ~ c= 0.20
Undisturbed, grassy areas = 0.00 AC C~ c= 0.35
Other areas = 2.00 AC C~1 c= 0.60
Total = 2.50 AC Cap c= 0.58
' Requtred design aspects of sediment trap
Required sediment volume of trap =_>
' The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
Sediment storage required = 900 CF
1 Key aspects of sediment trap as designed
Design dimensions for sediment trap based on required sediment storage amount =_>

Sediment storage depth needed = 3.0 ft
Surface area required = 300 SF
Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 15.00 ft (measured at bottom of trap)
Sediment trap width = 30.00 ft (measured at bottom of trap)
Surface area provided = 450.00 SF OK
Sediment storage volume provided = 1350.00 CF
Sediment trap required dimensioning for flood passage =_>
'* Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
'" Pass 010 over rip-rap weir with 0.50 foot minimum freeboard
"" Max. depth of flow over weir = 1.0 foot
Length of spillway required (max. depth of flow = 1.0 ft.) __>
Regional ten year storm intensity, 110 = 7.22 in/hr
010 = 10.47 cfs
Weir length = 10.0 ft

' Depth of flow for this weir length = 0.50 ft OK
Resultant depth to top of berm = 4.50 ft
' Final min/mum dimensions for sediment trap

Depth to top of berm = 4.5 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 15 feet
Length = 30 feet
Length of Weir = 10.0 feet (minimum)
Note: Sediment trap dlmens/ons g/ven (length and width) are d/mens/ons for
the bottom of the sediment trap.
1

i

'
Sediment Trap Sizing
(Reference: NC Sediment and Erosion Control Manual)
' Project and Protect Number =Park at Langston
Sediment Trap ID = 3
Location of Sediment Trap =

Drainage Area description to sediment crap
Disturbed earth (this protect) = 0.30 AC ~ c= 0.50
Undisturbed, wooded areas = 1.50 AC C~ c= 0.20
Undisturbed, grassy areas = 0.00 AC C~ c= 0.35
Other areas = 0.00 AC C~ c= 0.95
Total = 1.80 AC C~ c= 0.25
Required design aspects of sediment trap
Required sediment volume of trap =_>
The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
Sediment storage required = 540 CF
' Kev aspects of sediment trap as designed
Design dimensions for sediment trap based on required sediment storage amount =_>
Sediment storage depth needed = 3.0 ft
Surface area required = 180 SF
r Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 20.00 ft (measured at bottom of trap)
Sediment trap width = 10.00 ft (measured at bottom of trap)
Surface area provided = 200.00 SF OK
' Sediment storage volume provided = 600.00 CF
Sediment trap required dimensioning for flood passage =_>
"Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
'" Pass Q10 over rip-rap weir with 0.50 foot minimum freeboard
" Max. depth of flow over weir = 1.0 foot
r Length of spillway required (max. depth of flow = 1.0 ft.) __>
Regional ten year storm intensity, 110 = 7.22 in/hr

i
Q10 = 3.25 cfs
Weir length = 10.0 ft
Depth of flow for this weir length = 0.23 ft
Resultant depth to top of berm = 4.23 ft
Final minimum dimens/ons for sediment trap
Depth to top of berm = 4.2 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 20 feet
Length = 10 feet
Len th of Weir = 10.0 feet minimum
OK
Note: Sediment trap dimensions given (length and width) are dimensions for
the bottom of the sediment trap.

Sediment Trap Sizing
(Reference: NC Sediment and Erosion Control Manual)
' Project and Prof ect Number =Park at Langston
Sediment Trap ID = 4
' Location of Sediment Trap =
Dralna9e Area description to sediment trap
Disturbed earth (this protect) = 0.55 AC C~ c= 0.50
Undisturbed, wooded areas = 0.60 AC @ c= 0.20
Undisturbed, grassy areas = 0.00 AC C~ c= 0.35
Other areas = 0.00 AC C~3 c= 0.95

Total = 1.15 AC C~ c= 0.34
' Required desl_gn aspects of sediment trap
' Required sediment volume of trap =_>
The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
Sediment storage required = 990 CF
' Key aspects of sediment trap as designed
' Design dimensions for sediment trap based on required sediment storage amount =_>
Sediment storage depth needed = 3.0 ft
Surface area required = 330 SF
' Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 30.00 ft (measured at bottom of trap)
Sediment trap width = 15.00 ft (measured at bottom of trap)
Surface area provided = 450.00 SF OK
' Sediment storage volume provided = 1350.00 CF
Sediment trap required dimensioning for flood passage =_>
' "Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
"` Pass 010 over rip-rap weir with 0.50 foot minimum freeboard
"' Max. depth of flow over weir = 1.0 foot
Length of spillway required (max. depth of flow = 1.0 tt.) __>
Regional ten year storm intensity, 110 = 7.22 in/hr

Q10 = 2.85 cfs
Weir length = 10.0 ft
Depth of flow for this weir length = 0.21 ft
Resultant depth to top of berm = 4.21 ft
Flna/ minimum dimensions for sediment trap
Depth to top of berm = 4.2 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 30 feet
Length = 15 feet
Len th of Weir = 10.0 feet minimum
OK
Note: Sediment trap dimensions Given (length and width) are dimensions for
the bottom of the sediment trap.

Sediment Trap Sizing
(Reference: NC Sediment and Erosion Control Manual)
Protect and Protect Number =Park at Langston
Sediment Trap ID = 5
Location of Sediment Trap =
Drainage Area description to sediment trap
' Disturbed earth (this project) = 1.00 AC ~ c= 0.50
Undisturbed, wooded areas = 2.00 AC C~ c= 0.20
Undisturbed, grassy areas = 0.00 AC C~ c= 0.35
Other areas = 0.00 AC C~3 c= 0.95
Total = 3.00 AC C~ c= 0.30
' Re4ulred design aspects of sediment trap
' Required sediment volume of trap =_>
The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
' Sediment storage required = 1800 CF
Kev aspects of sediment trap as designed
' Design dimensions for sediment trap based on required sediment storage amount =_>
Sediment storage depth needed - 3.0 ft
Surface area required = 600 SF
Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 20.00 ft (measured at bottom of trap)
' Sediment trap width = 40.00 ft (measured at bottom of trap)
Surface area provided = 800.00 SF OK
' Sediment storage volume provided = 2400.00 CF
Sediment trap required dimensioning for flood passage =_>
' '" Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
*' Pass Q10 over rip-rap weir with 0.50 foot minimum freeboard
" Max. depth of flow over weir = 1.0 foot
' Length of spillway required (max. depth of flow = 1.0 ft.) __>
Regional ten year storm intensity, 110 = 7.22 in/hr

' Q10 =
Weir length =
' Depth of flow for this weir length =
Resultant depth to top of berm =
Final min/mum dimenslons for sediment trap

6.50 cfs
10.0 ft
0.36 ft
4.36 ft
OK
Depth to top of berm = 4.4 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 20 feet
Length = 40 feet
Len th of Weir = 10.0 feet minimum
Note: Sediment trap dimenslons given (length and width) are dimenslons for
the bottom of the sediment trap.

Sediment Trap Sizing
(Reference: NC Sediment and Erosion Control Manual)
Prolect and Project Number =Park at Langston
Sediment Trap ID = 6&7
Location of Sediment Trap =
Drainage Area descrlpt/on to sediment trap
Disturbed earth (this Prolect) = 0.25 AC C~3 c= 0.50
Undisturbed, wooded areas = 0.25 AC ~ c= 0.20
Undisturbed, grassy areas = 0.00 AC ~ c= 0.35
Other areas = 0.00 AC ~ c= 0.95
Total = 0.50 AC C~1 c= 0.35
Required design aspects of sediment trap
Required sediment volume of trap =_>
The sediment trap must provide 1800 CF of sediment storage per disturbed acre of land. This is
approximately one year of sediment storage.
Reduction Factor permitted by erosion control authority = 1
Associated cleanout period for reduction factor = One year
Sediment storage required = 450 CF
Kev aspects of sediment trap as designed
Design dimensions for sediment trap based on required sediment storage amount =_>
Sediment storage depth needed = 3.0 ft
Surface area required = 150 SF
Bottom of trap dimensions to provide required surface area and maintain a 2:1 length to width ratio =_>
Sediment trap length = 20.00 ft (measured at bottom of trap)
Sediment trap width = 10.00 ft (measured at bottom of trap)
Surface area provided = 200.00 SF OK
Sediment storage volume provided = 600.00 CF
Sediment trap required dimensioning for flood passage =_>
" Add 0.50 foot of flood storage above sediment storage zone (to set rip-rap weir)
"* Pass Q10 over rip-rap weir with 0.50 foot minimum freeboard
`" Max. depth of flow over weir = 1.0 foot
Length of spillway required (max. depth of flow = 1.0 ft.) __>
Regional ten year storm intensity, 110 = 7.22 in/hr

Q10 = 1.26 cfs
Weir length = 10.0 ft
Depth of flow for this weir length = 0.12 ft
Resultant depth to top of berm = 4.12 ft
Flna/ minimum dimensions for sediment trap
Depth to top of berm = 4.1 feet
Depth to crest of spillway = 3.5 feet
Sediment Storage Depth = 3.0 feet
Width = 20 feet
Length = 10 feet
Len th of Weir = 10.0 feet minimum
OK
Note: Sediment trap dimensions given (length and width) are dimensions for
the bottom of the sediment trap.