20070208 Ver 2_More Info Received_20071127

kV
CLH design, p.a.
MacGregor Park, 125 Edinburgh South, Suite 310
Cary, North Carolina 27511
Phone: [phone] Fax.• [phone]
Email.• [e-mail]
LETTER OF TRANSMITTAL \r 2s-Nov-o7
To: Cyndi Karoly ~ X.p 01 ' ~ ~. ~ ~ ~l
Company: Division of Water Quality
Address: 2321 Crabtree Blvd, Suite 250
City, State Zip: Raleigh, NC 27604
Phone: [phone]
Fax: [phone]
Method: Hand Delivery
Subject: Heritage HS CLH Project Number: 1123
® Prints ^ Originals ^ Specifications ®Applications
^ Reports ^ Copy of Letter ^ Submittals ^ Other:
We are sending you the following items:
No. of Copies Date Description
• 4 Full Size Plan Set
• 4 Stormwater Management Permit Application- Level Spreader
• 4 Checklist
• 4 Design Calculations
• 4 Maintanence and Inspections Agreement
Additional Remarks:
As requested, please find the above information enclosed for your use.
If there are any questions, or if additional information is required, please feel free to call.
Signed
Steven J. Miller, PE
cc: File
1123/permit
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D~P~lR - WpTFR QUAI.! ~`
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' •- Soil. & Environmental Consultants, PA
11010 Raven Ridge Road • Raleigh, North Carolina 27614 Phone: {919) 846-5900 Fax: (919) 84C-9467
www.SandEC.com
November 26, 2007
S&EC Project #471B.Wf3
DWQ EXP Project: #07-0208v2
Department of Environment and Natural Resources
Division of Water Quality
Attn: Cyndi KarolylLia Myott .---s
2321 Crabtree Hattevard, Sude 250 ^ '' ~` ~ ~' ~ ~ ~' ~
f-..t~:l~~-f ~.-
a.~ ~=-~ ....~
Raleigh, NC 27004 D° ,_,_,'~ ~~=
Re: Reply to the Division of Water Quality's Request for More information ~ ~ ;,; ~, V ';~ "~ ~~~~
Heritage High School-EXPRESS RE1f1EW PROGRAM ~ ~~~ 1J
Wake County, NC Dttd;t - ,~1A1 ~K ~~-!~
1l~~jClA MPt~ $'~Q~~N~,~~
To Whom !t May Concern:
The purpose of this letter is to respond to your Request for More Information letter dated November 9,
2007. i3ecause of site design challenges associated with existing topograpfiy and sizable floodplains
surrounding the property, a meeting was requested with your office on November 14, 2007. On
November 21, 2007, this meeting was held to review and discuss the OWQ's remaining questions. The
original questions are copied below as they appear within the November 8, 2007 letter and. are then
fdkrived by our response.
Additional tnformatiorl Requested:
1. Generallnformation:
a. In order b achieve flow provisions, you have proposed a number of dissipater pads at the end of
the outflow pipes from all BMP's without providing the outlet velocities of your dissipater pads.
Please provide the information on the outlet lrelocities, including pipe sizes, slopes, and flow rates
used for skiing the aprons. Additionally, p/ease.provide the elevations and invert lave/s necessary
tar construction purposes on the appropriate site plans and/or in the supporting documentation.
As reviewed and discussed in our meeting on November 21, 2.007, please see attached design.
details.
b. Please provide Figure 8.08.b.2 used for sizing the aprons. Only Figures 8.08.b.1 is provided on
page 4 of the supporting docurhents.
As reviewed and discussed in our meeting on November 21, 2007, please see attached Figure
8.08.b.2.
2. Level Spreader.
a, The Length of the proposed level spreader is too short Please provide a length adequate for a
design flow of 1.269 cfs, and a forest filter strip. Please see Table 8.1 in fhe North Carolina Division
of Water Quality Stormwater Best Managemenf Practices Manus. The length (1t) of level spreader
lip needed per cfs is missing on tiie Supplement Form.
As reviewed and discussed in our meeting on November 21, 2007, there was an error within
the supplement forth. The attached completed supplement form indicates the correct level
spreader length.
Charlotte Office: Sr~8boro Office:
236 LePhillip Court, Suite C 3817-E Lavvndale lkive
Concord, NC 28025 Greensboro, NC 27455
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]

b. Freese sign and notarize the Inspection and Maintenance Agreement for the Ftlter Strip and Level
Spreader.
As reviewed and discussed in our meeting on November 21, 2007, please sea attached signed
and notarized Inspection and Maintenance Agreement.
c. Please provide a date tamped photo of the tt7ter strip and the apiropriate response as required In
Items 4 and 5 of the Requtred Items Checklist
As reviewed and discussed in our meeting on November 21, 2007, please sea attached photos.
d. Please provide site plans that meet specifred requbemerrts in the Required /tams Checklist. For
example, plan sheets C3.0, C3.2 and C8.2 do rat show the entire site andlor are not at the
appropriate scale.
As reviewed and discussed in our [Heating on November 21, 2007, please see attached overall
alts plan that was previously submitted with our original application submittal.
3. Wet Detention Pond G
a. Flow from outlet structure associated with Wet Detention Pond G would' not be diffused, but rather
channelized in the draw down stops of the dissipater pad. Please relocate the outlet structure.
As reviewed and discussed in our meeting on November 21, 2007, please see attached
modifications of eke plan below the outlet structure of Wet Detention Pond G.
We anticipate that this answers all of the DWQ's questions in order to complete the final review process
for Water Cluality Certification 3625 and Riparian Buffer Authorization. ff you have any further questions or
any additional explanation is needed, please don't hesitate to calf.
Sinaarely,.
_(" o
Debbie Edwards
Environmental $peciaiist
CC:
Susan Holt-LS3P Associates
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NCDENR ~X Q o'1 - 0 2 ~ $ V' Z
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER, FILTER STRIP AND RESTORED RIPARIAN BUFFER SUPPLEMENT
This form must be filled out, printed and submitted.
_.
r .. , ~ ~ _.
1. PROJECT INFORMATION
Project name Heritage High Schcol
Contact name Steve Miller, PE
Phone number 919-319.6716
Date November 26, 2007
Drainage area number B6
il. DESIGN INFORMATION
For Level Spreaders Receiving Flow From a BMP
Type of BMP N/A
Drawdown flow from the BMP 0 cfs
For Level Spreaders Receiving Flow from the Drainage Area
Drainage area
Impervious surface area
Percent impervious
Rational C coefficient
Peak flow from the 1 in/hr storm
Time of concentration
Rainfall intensity, l0-yr storm
Peak flow from the 10-yr storm
Where Does the Level Spreader Discharge?
To a bioretention cell?
To a wetland?
To a filter strip or riparian buffer?
Other (specify)
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass
Width of dense ground cover
Width of wooded vegetation
Total width
Slope (from level lip to to top of bank)
Are any draws present?
Level Spreader Design
Forebay surface area
Feet of level lip needed per cfs
Answer "Y" to one of the following:
Length based on the 1 in/hr storm?
Length based on the 10-yr, 24-hr storm?
Length based on the BMP discharge rate?
Design flow
Is a bypass device provided?
Length of the level lip
Are level spreaders in series?
108,4Q0 ft
33,970 ftz
0.31
0.51
1.269146006 cfs
min
7.22 in/hr
9.16323416 cfs
N (Y or N)
Y (Y or N) Do not need to complete filter strip characterization below.
N (Y or N)
54 ft
ft
ft
50 ft
5
N (Y or N)
68 sq ft
13 ft/cfs
Y (Y or N)
N (Y or N)
N (Y or N)
1.269 cfs
Y (Y or N)
26 ft
N (Y or N)
OK
OK
OK
Level spreader length OK.
Form SW401-Level Spreader, Fiker Strip, Restored Riparian Buffer-Rev.2 Parts I. and II. Design Summary, page 1 of 2

Bypass Channel Design (if applicable)
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Dimensions of the channel (see diagram below):
M
B
W
Y
Peak velocity in the channel during the 10-yr, 24-hr storm
Channel lining material
Y (Y or N) Redesign channel to discharge to a dissipator pad adjacent to the w
NIA
N/A ft
N/A ft
N/A ft
NIA ft
NIA cfs
NIA
far
`~`
t 1------------
M
i a i
/~ 1
-------------1
M
Form SW401-Level Spreader, Fiker Strip, Restored Riparian Buffer-Rev.2 Parts I. and II. Design Summary, page 2 of 2

111, REQlt1RE#) ITEMS CHECKL,#ST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will
result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to
indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Pagel Plan
Initials Sheet No.
~ c3. Z 1. Plans (1" - 50' or larger) of the entire site showing:
c 8. Z -Design at ultimate build-out,
+- -Off-site drainage (if applicable),
Go • ~ -Delineated drainage basins (include Rational C coefficient per basin),
-Forebay (if applicable),
-High flow bypass system,
-Maintenance access,
-Recorded drainage easement and public right of way (ROW), and
-Boundaries of drainage easement.
~~ G~• !to 2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
-High flow bypass system,
-One foot topo lines between the level lip and top of stream bank,
-Recorded drainage easement, and
-Design at ultimate build-out.
~ G7' r(~ 3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
- Level lip,
- Upslope channel, and
/~ - Downslope filter fabric.
!3`Y!'1 ~ ~ [= -t 4. Adate-stamped photograph of the filter strip that clearly shows the type of vegetation that is present.
~~ ~ C ~•ytO 5. An assurance that the installed system will meet design specifications upon initial operation once the
project is complete and the entire drainage area is stabilized.
o`'!Y1 C+~ o t 6. A construction sequence that shows how the level spreader will be protected from sediment until the entire
drainage area is stabilized.
~+'f ~' ~ 7. The supporting calculations.
~ fin' ~ 8. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
~~ ~ 9. A copy of the deed restriction.
t ~ ~ ~n/Sfl2uL~'Jon~ S~C3tJ6-I[.~ ~T2-:--rr '~22 a.J Gy.o .
Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.2 Part III, page 1 of 1

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DESK ltii CALCULA'T'IOItiiS
CIVILISITE WORK
HERI'TAG~ HIGH SCHOOL
WAKE FOREST, NORTH CAROLINA
DECEMBER, 2006
REV. MaRCti , 2007
REV. Nov. 2007
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CL,H desi n .a.
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MacGregor Park, 125 Edinburgh South, Suite 3I0
Cary, North Carolina 27511
Phone: [phone] Fax.• (919) 3I9-7516

OLJ"t'L~'T' PRO'T'EC"i'IOI~i
D~si~H

"~ ~ ° ~ +~ -DATE DESIGN PHASE
'a 11-21-07 PRELIM / /
PR J T ME PROJE T NO CONSTR / /
Heritage Hi h School 1123 REVISION / x /
L AT BY RECORD / /
Wake Forest, NC KAL OTHER / /
HECKE BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= A5 Quo/Qfull = 0.27
Pipe Dia= 15 in V/Vfull = 0.83
Quo = 5.52 cfs V~o = 13.6 fps
Qfull = 20.20 cfs Slope= 5.0
Vfull = 16.40 fps Pipe Inv= 274.00 ft
From Fig. 8.06.b.1: Zone = 2
From Fig. 8.06.b.2: Dso = 8 in
pMgx = 12 in
Riprap Class = B
S Apron Thickness = 18 in
Apron Length = 7.5 ft
3 Apron Width = 3xDia = 4 ft
Length
F--- '
Storm Outlet Structure
FES No.= B6 Quo/Qfull = 0.52
Pipe Dia= 18 in V/Vfull = 1.00
Quo = 10.56 cfs V~o = 11.5 fps
Qfull = 20.40 cfs Slope= 4.7
Vfull = 11.50 fps Pipe Inv= 221.60 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o _ = 10 in
Dnnax = 15 in
- Riprap Class = 1
s Apron Thickness = 22.5 in
:3 Apron Length = 12 ft
1 Apron Width = 3xDia = 5 ft
I Length I

~ - - wt • DATE DESIGN PHASE
11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR I I
Herita a High School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJ M
Storm Outlet Structure
FES No.= C17 Quo/Qfull = 0.69
Pipe Dia= 30 in VNfull = 1.07
Quo = 72.18 cfs V~o = 23.0 fps
Qfull = 105.20 cfs Slope= 5.0
Vfull = 21.40 fps Pipe Inv= 218.00 ft
From Fig. 8.06.b.1: Zone = 6
From Fig. 8.06.b.2: Dso = 14 in
p~ = 21 in
- Riprap Class = 2
Apron Thickness 31.5 in
Apron Length 25 ft
3 Apron Width = 3xDia = 8 ft
Length
Storm Outlet Structure
FES No.= D3 Quo/Qfull = 0.44
Pipe Dia= 15 in VNfull = 0.96
Quo= 3.15 cfs V~o= 5.7 fps
Qfull = 7.20 cfs Slope= 4.8
Vfull = 5.90 fps Pipe Inv= 279.80 ft
From Fig. 8.06.b.1: Zone = 2
From Fig. 8.06.b.2: Dso = 8 in
p~ = 12 in
- Riprap Class = B
s Apron Thickness _ 18 in
Apron Length 7.5 ft
3 Apron Width = 3xDia = 4 ft
Length

~ `~ ~~ DATE DESIGN PHASE
~_~ ~- ° 11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Heritage High School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= F13 Quo/Qfull = 0.96
Pipe Dia= 36 in VNfull = 1.14
Quo= 64.90 cfs V~o= 10.8 fps
Qfull = 67.50 cfs Slope= 5.0
Vfull = 9.50 fps Pipe Inv= 225.00 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o = 10 in
pMgx = 15 in
Riprap Class = 1
s Apron Thickness = 22.5 in
Apron Length = 24 ft
3
Apron Width = 3xDia = 9 ft
Length I
Storm Outlet Structure
FES No.= G2 Quo/Qfull = 0.66
Pipe Dia= 15 in VNfull = 1.07
Quo = 6.74 cfs Vto = 8.8 fps
Qfull = 10.20 cfs Slope= 3.5
Vfull = 8.30 fps Pipe Inv= 233.50 ft
From Fig. 8.06.b.1: Zone = 2
From Fig. 8.06.b.2: D5o = 8 in
p~ = 12 in
Riprap Class = B
L Apron Thickness = 18 in
~_ ~ Apron Length = 8 ft
3 Apron Width = 3xDia = 4 ft
I Length

~ ~ - ~ • DATE DESIGN PHASE
~ 11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Herita a High School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= H10 Quo/Qfull = 0.75
Pipe Dia= 30 in VNfull = 1.10
Quo= 31.63 cfs V~o= 9.3 fps
Qfull = 42.00 cfs Slope= 5.0
Vfull = 8.50 fps Pipe Inv= 215.00 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o = 10 in
p~ = 15 in
- Riprap Class = 1
Apron Thickness = 22.5 in
Apron Length = 20 ft
- 3 Apron Width = 3xDia = 8 ft
_~
Length
Storm Outlet Structure
FES No.= POND A Q1o/Qfull = 0.11
Pipe Dia= 24 in VNfull = 0.67
Quo = 7.45 cfs V~o = 14.2 fps
Qfull = 66.20 cfs Slope= 2.0
Vfull - 21.10 fps Pipe Inv= 263.00 ft
From Fig. 8.06.b.1: Zone = 5
From Fig. 8.06.b.2: D5o = 14 in
p~ = 21 in
Riprap Class = 2
Apron Thickness = 31.5 in
Apron Length = 20 ft
3 Apron Width = 3xDia = 6 ft
_1
I _Length
III--- -'~

PROJECT NAME
Herita a High School
LOCATION
Wake Forest, NC
Storm Outlet Structure
FES No.= POND B
Pipe Dia= 42 in
Quo = 6.04 cfs
Qfull = 122.00 cfs
Vfull = 12.70 fps
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
s
3
I ..Length I
Storm Outlet Stru
FES No.= POND C
Pipe Dia= 30 in
Q~ o = 2.36 cfs
Qfull = 44.20 cfs
Vfull = 9.00 fps
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
Zone
D50
DnnAx
Riprap Class
Apron Thickness
Apron Length
Apron Width = 3xDia
cture
3
(_
I Length
Zone
D50
DnnAx
Riprap Class
Apron Thickness
Apron Length
Apron Width = 3xDia
DATE DESIGN PHASE
11-21-07 PRELIM
PROJECT NO CONSTR
1123 REVISION
BY RECORD
KAL OTHER
CHECKED BY (SPECIFY)
SJM
Quo/Qfull = 0.05
VNfull = 0.52
V~o= 6.6 fps
Slope= 1.8
Pipe Inv= 214.00 ft
= 3
= 10 in
= 15 in
= 1
= 22.5 in
= 28 ft
= 11 ft
Quo/Qfull = 0.05
VNfull = 0.52
V~o = 4.7 fps
Slope= 4.0
Pipe Inv= 211.00 ft
= 3
= 10 in
= 15 in
= 1
= 22.5 in
= 20 ft
= 8 ft

• - ~ ~ DATE DESIGN PHASE
~ 11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Heritage High School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= POND D Quo/Qfull = 0.36
Pipe Dia= 36 in VNfull = 0.91
Quo = 28.37 cfs V~o = 10.1 fps
Qfull = 78.60 cfs Slope= 8.3
Vfull = 11.10 fps Pipe Inv= 221.00 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o = 10 in
p~ = 15 in
Riprap Class = 1
Apron Thickness 22.5 in
Apron Length 24 ft
3 Apron Width = 3xDia = 9 ft
Length
Storm Outlet Structure
FES No.= J2 Quo/Qfull = 0.12
Pipe Dia= 15 in VNfull = 0.67
Quo = 0.81 cfs V~o = 3.8 fps
Qfull = 6.80 cfs Slope= 5.0
Vfull = 5.60 fps Pipe Inv= 215.00 ft
From Fig. 8.06.b.1: Zone = 2
From Fig. 8.06.b.2: D5o = 8 in
p~ = 12 in
- ~ Riprap Class = B
~' Apron Thickness = 18 in
Apron Length = 8 ft
3 Apron Width = 3xDia = 4 ft
Length I

~ ~ ~° '- ~- •
>~'; ~ - DATE DESIGN PHASE
,
~a r_± - ~ 11-26-07 PRELIM / /
,
PROJECT NAME _ PROJECT NO CONSTR / /
Herita a Hi h School 1123 REVISION / x /
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJ M
Storm Outlet Structure
FES No.= POND G Quo/Qfull = 0.25
Pipe Dia= 18 in VNfull = 0.83
Quo = 8.51 cfs V~o = 15.9 fps
Qfull = 33.70 cfs Slope= 21.0
Vfull = 19.10 fps Pipe Inv= 261.00 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o = 10 in
Dnnwc = 15 in
~ Riprap Class = 1
=I Apron Thickness = 22.5 in
Apron Length = 12 ft
Apron Width = 3xDia = 5 ft
I Length
Storm Outlet Structure
FES No.= A8 Quo/Qfull = 0.07
Pipe Dia= 15 in VNfull = 0.52
Quo = 1.33 cfs V~o = 8.3 fps
Qfull = 19.60 cfs Slope= 7.0
Vfull = 15.90 fps Pipe Inv= 276.00 ft
From Fig. 8.06.b.1: Zone = 3
From Fig. 8.06.b.2: D5o = 10 in
Dnnax = 15 in
Riprap Class = 1
_. ~ Apron Thickness = 22.5 in
Apron Length = 10 ft
3 Apron Width = 3xDia = 4 ft
Length

~ - ~ ~ s DATE DESIGN PHASE
~ 11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Heritage Hi h School 1123 REVISION / x /
LOCATION BY RECORD 1 /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= A10 Quo/Qfull = 0.38
Pipe Dia= 18 in VNfull = 0.93
Quo = 5.83 cfs V~o = 8.1 fps
Qfull = 15.40 cfs Slope= 9.1
Vfull = 8.70 fps Pipe Inv= 281.00 ft
From Fig. 8.06.b.1: Zone = 2 '
From Fig. 8.06.b.2: D5o = 8 in
p~ = 12 in
- ~ Riprap Class = B
L Apron Thickness = 18 in
Apron Length = 9 ft
3 Apron Width = 3xDia = 5 ft
Length
Storm Outlet Structure
FES No.= LEVELSPREADER B6 Quo/Qfull = 1.00
Weir Wth= 36 in VNfull = 1.14
Quo = 7.90 cfs V~o = 3.6 fps
Qfull = 7.90 cfs Slope= 5.0
Vfull = 3.20 fps Pipe Inv= 213.90 ft
From Fig. 8.06.b.1: Zone = 2
From Fig. 8.06.b.2: D5o = 8 in
p~ = 12 in
Riprap Class = B
y Apron Thickness = 18 in
Apron Length = 18 ft
3 Apron Width = 3xDia = 9 ft
I Length

ti` ' ` ~' ° ° ~ +~ "~ .`' ~"" ~ DATE DESIGN PHASE
~i 4 „~~;. 11-21-07 PRELIM / /
PROJECT NAME PROJECT NO CONSTR / /
Heritage High School 1123 REVISION / x I
LOCATION BY RECORD / /
Wake Forest, NC KAL OTHER / /
CHECKED BY (SPECIFY)
SJM
Storm Outlet Structure
FES No.= Culvert at Outfall
Pipe Dia= 15 in
Q~ o = 13.51 cfs
Qfull = 13.51 cfs
Vfull = 2.40 fps
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
Quo/Qfull = 1.00
V/Vfull = 1.14
V~o = 2.7 fps
Slope= 0.2
Pipe Inv= 281.00 ft
Zone = 2
D5o = 8 in
pnnAx = 12 in
Riprap Class = B
Apron Thickness = 18 in
Apron Length = 8 ft
Apron Width = 3xDia = 4 ft
Storm Outlet
FES No.=
Weir Wth=
Q10 =
Qfull =
Vfull =
From Fig. 8.06.b.1:
From Fig. 8.06.b.2:
3
Length
Zone
D50
Dnnax
Riprap Class
Apron Thickness
Apron Length
Apron Width = 3xDia
Quo/Qfull = #DIV/0!
V/Vfull = #DIV/0!
V~o = #DIV/0! fps
Slope=
Pipe Inv= ft
= 2
= 8 in
= 12 in
= B
= 18 in
= 0 ft
= 0 ft
ructure
in
cfs
cfs
fps

Appendices
NEW YORK DOT DISSIPATOR METHOD
FOR USE IN DEFINED CHANNELS
(Source: "Bank and channel lining procedures", New York Department
of Transportation, Division of Design and Construction, 1971.)
1 Note: To use the following chart you must know:
(1) Q full capacity
(2) Qto
(3) V full
(4) Vto
where Q = discharge in cfs and V =Velocity in FPS.
ESTIMATION OF STONE SIZE AND DIMENSIONS FOR
CULVERT APRONS
Step 1) Compute flow velocity Vo at culvert or paved channel outlet.
Step 2) For pipe culverts Do is diameter.
For pipe arch, arch and box culverts, and paved channel outlets,
Do=Ao, where A: cross-sectional area of flow at outlet.
For. multiple culverts, use Do=1.25xDo of single culvert.
Step 3) For apron grades of ld% or steeper, use recommendations
For next higher zone. (Zones 1 through 6).
25 -
20 -
~ 15-
U
O 10-
t--.
5-
ii~ li i~~lii iiiiilii i .11 .11 II,
111111111 11111 II111 rlllll 1111111 Illirllilll
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0' 5'
Figure 8.06.b.1
I I
10' 15' 20' 25'
DIAMETER (Ft.)
Rev. 12/93 8.O6.S

w
~~ ~~~ PROfEC7 CULYERf

Ll TO AAEYEM SCOUR
HOIf USE L2 ALWAYS
L2
1 STONE FILLING {FINE} CL. A 3 x Do 4 x Do
2 STONE FILLING (LIGHT) CL. 6 3 x Do 6 x De
3 STONE FILIfNG {MEDIUM) CL. 1 4 x Do 8 x Do
4 STONE FILLING (HEAVY} CL. 1 d x Do 8 x Do
5 STONE FILLING (HEAVY) CL. 2 5 x Do t0 x Da
6 STONE FILLING (HEAVY} CL. 2 8 x bo lt) x De
7 SPECIAL STUDY REQUIREb {ENERGY DISSIPATORS, STILLING
BASIN OR LARGER SIZE STONE).
Fig. 8.06.b.2

Width ~ 3 times pipe dia. (min.}

NGDC)T RIPRAP CHANItiIEL DESICI`I DATA
RIPRAP MANN[NG'S N VALUE FOR DEPTH RANGES PERMISSIBLE
CLASS D50
(1N) O~O.5
(FT) 0.5-1 .O
{FT) 1 .0-2..0
{FT} >2.O
(FT) SHEAR STRESS
TD (PSF)
CLASS A 4 0.076 0.044 0.039 0.036 1 .65
CLAss B 8 0.179 0.063 O.G56 0.045 3.37
CLASS I 1 O 0.409 0.073 0.061 0.049 4.20
CLASS lI 1 2 0.797 0.084 0.060 0.053 5.00
5auRCe: NCdOT U 989)

~.x. o~ • o ao ~ v ~,
C~HH~~ D~S~CH

iy i``+ ~ g '.: ~ ~ DATE DESIGN PHASE

PROJECT NAME PROJECT NO DD / /
Herita a HS 1123 CD / X /
LOCATION BY REV / /
Wake Forest, NC bsl OTHER / /
CHECKED BY (SPECIFY)
X
PERMANENT LINING -Permissible Velocity and Capacity
Channel No: CHANNEL-50 Drainage Area: 0.75 ac
Sta from: Design Fequency: 10 yrs
Sta to: Time of Conc: 5 min
Section Length: 90 ft Intensity: 7.22 in/hr
Section Slope: 15.60 % Runoff Coeff: 0.30
Ret Class: B Discharge: 1.62 cfs
Permissible Velocity: 4.50 fps Plus Pond 'G' Q: 8.51 cfs
Allowable Depth: 2.00 ft = 10.13 cfs
Swale sizing method done by manipulation of Manning's Equation to find the depth
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Qp = 10.13 cfs flow by Rational Method
n = 0.22 Grass Manning's Coefficient (dimensionless)
S = 0.156 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 3.79 quantity to equate to Zav
M = 8 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
6 0.50 5.00 14.06 0.36 2.51 shallow
6 0.55 5.72 14.87 0.38 3.03 shallow
6 0.60 6.48 15.67 0.41 3.60 shallow
6 0.61 6.64 15.84 0.42 3.72 OK
B = bottom width of trapezoidal channel
Zav = 7req
D = normal depth of flow
A = cross-sectional area of flow ~ Rxr~ _ 4?n
P = wetted perimeter of the channel 1.4~ ~/s
R = hydraulic radius of the channel
Normal Depth, D = 0.61 ft Depth O.K.
Velocity= 1.53 fps Vel. O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 5.94 Ib/sq-ft
FINAL CHANNEL LINING DIMENSIONS
B = Eft side slopes, M = 8 :1
D = 2.0 ft top width, W = 38.0 ft
Permanent Channel Lining: Grass
(REF: Malcom, 1991)
Page 1

~ DATE DESIGN PHASE
d 11-26-07 S D / /
PROJECT NAME PROJECT NO DD / /
Herita a HS 1123 CD / x /
LOCATION BY REV / /
Wake Forest, NC bsl OTHER / /
CHECKED BY (SPECIFY)
X
PERMANENT LINING -Permissible Velocity and Capacity
Channel No: CHANNEL-51 Drainage Area: 2.18 ac
Sta from: Design Fequency: 10 yrs
Sta to: Time of Conc: 5 min
Section Length: 215 ft Intensity: 7.22 in/hr
Section Slope: 11.60 % Runoff Coeff: 0.30
Ret Class: B Discharge: 4.72 cfs
Permissible Velocity: 4.50 fps Plus Pond 'G' Q: 8.51 cfs
Allowable Depth: 2.00 ft = 13.23 cfs
Swale sizing method done by manipulation of Manning's Equation to find the depth
of flow that matches the known flow conditions. Performed by trial and error.
INPUT DATA
Qp = 13.23 cfs flow by Rational Method
n = 0.17 Grass Manning's Coefficient (dimensionless)
S = 0.116 ft/ft longitudinal slope (ft of fall per ft of run)
Zreq = 4.43 quantity to equate to Zav
M = 8 :1 side slope of channel (ft of run : 1 ft of rise)
NORMAL DEPTH AND VELOCITY
B D A P R Zav Remark
6 0.50 5.00 14.06 0.36 2.51 shallow
6 0.70 8.12 17.29 0.47 4.91 deep
6 0.60 6.48 15.67 0.41 3.60 shallow
6 0.66 7.44 16.64 0.45 4.35 OK
B = bottom width of trapezoidal channel Zav _ 7req
D = normal depth of flow
A = cross-sectional area of flow A Rzr~ _ Qn
P = wetted perimeter of the channel 1.d9 ~
R = hydraulic radius of the channel
Normal Depth, D = 0.66 ft Depth O.K.
Veloci = 1.78 fps Vel. O.K.
SHEAR STRESS
T = yds =shear stress in Ib/sq-ft
Y = unit weight of water, 62.4 Ib/cu-ft
D = normal depth of flow in ft
S =longitudinal slope in ft/ft
shear stress, T = 4.78 Ib/sq-ft
FINAL CHANNEL LINING DIMENSIONS
B = Eft side slopes, M = 8 :1
D = 2.0 ft top width, W = 38.0 ft
Permanent Channel Lining: Grass
(REF: Malcom, 1991)
Page 1

~xP off- oao8 v2
LEVEL SPREADER

PROJECT NAME
Heritage Hicth School
Forest, NC
For Level Spreaders Receiving Flow From a BMP
Type of BMP
Drawdown flow from the BMP cfs
For Level Spreaders Receiving Flow from the Drainage Area
Drainage area 108,400 ft2
Impervious surface area 33,970 ft2
Percent impervious 0.31
Rational C coefficient 0.51
Peak flow from the 1 in/hr storm 1.269 cfs
Time of concentration 5 min
Rainfall intensity, 10-yr storm 7.22 in/hr
Peak flow from the 10-yr storm 9.16 cfs
Where Does the Level Spreader Discharge?
To a bioretention cell? N (Y or N)
To a wetland? Y (Y or N)
To a filter strip or riparian buffer? N (Y or N)
Other (specify)
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass 50 ft
Width of dense ground cover ft
Width of wooded vegetation 0 ft
Total width 50 ft
Slope (from level lip to to top of bank) 6
Are any draws present? N (Y or N)
Level Spreader Design
Forebay surface area 68 - sq ft
Feet of level lip needed per cfs 13 ftlcfs
Answer "Y" to one of the following:
Length based on the 1 in/hr storm? Y (Y or N)
Length based on the 10-yr, 24-hr storm? N (Y or N)
Length based on the BMP discharge rate? N (Y or N)
Design flow 1.27 cfs
Is a bypass device provided? Y (Y or N)
Length of the level lip 17 ft
Are level spreaders in series? N (Y or N)
DATE ,_ ;~
11-21-07 ~ j ~~~ ,%' J
PROJECT NO _ _ ~-- '
~
f1 it
1123 ~
~f__, ~ ~-'
BY ~~ ~~
KAL
Use 26 ft
s:11 3 1 910 0 01\calcs\1123-LevelSpreader.XLS ~ printed: 111211200710:43 AM Page 1 of 2

s:\1 31 910 0 0 1\calcs11123-LevelSpreader.XLS printed: 11/2112007 10:43 AM Page 2 of 2

~~ L~

,~7r•
Filter Strip, Restored Riparian Suffer and Level Spreader
Inspection and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of inspection and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential roblem: How I will remediate the roblem:
The entire filter strip Trash/debris is present. Remove the trash/debris.
s stem
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clo ed. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
re air.

BMP element: Potential roblem: How I will remediate the roblem:
The Swale and the level The Swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise dama ed.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and aone-time fertilizer
a lication.
Trees or shrubs have begun Remove them.
to grow on the Swale or just
downslo e of the level li .
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish ro er erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if a licable). a roximatel three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer a lication.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer a licadon.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide aone-time
fertilizer a lication.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversi ht Unit at 919-733-1786.

I acknowledge and agree by my signature below that~ir, se~nsible for the
performance of the maintenance procedures listed aboveK.Fagreesto notify DWQ of any
problems with the system or rior to ny changes to the system or responsible party.
Donald M.pHaydon, ~r.
Print name: F ~ OperahOnB Offltle~
Title:
WAILC GOU//T~ ~/P-~~-[G SG G1DC.. SysT~~
Address: ASS/ ,pock- C1 va.r-~~ ,~v, , 1=-~4 ~ r ~~( ,J c_ ZT ~~ a
Signature:
Date: %rV~J7J 1 ~
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, ;~hrr ~, , ~~,~~ ;,~ , a Notary Public for the State of
~C[.~.-v lr n cam.. ,County of jt/~r„~c, , do hereby certify that
~~~d ~. .,,,~,rJm~ /r , personally appeared before me this ~~'
day of ~v.rcl.,~, ~_, , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
..,..e,.~...,..<..
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T ''•~,
z
***
a =~ _
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SEAL
My commission expires d~~~-~ ~ ~D (1~

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