19970776 Ver 1_Complete File_19970908

!ice THE JOHN R. WADAMS COMPANY, INC.
CONSULTING ENGINEERS
POST OFFICE BOX 14005
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709 %/ [phone] FAX [phone] ??4,
Nrq?s?/F,s
17,0717k
LETTER OF TRANSMITTAL T)
To: Mr. Ray Cox Date: October 27, 1997
NCDEHNR
4401 Reedy Ck. Road
Raleigh, North Carolina 27607 ** HAND DELIVER **
Re: William R. Davie Middle School Job No: DGT-96010
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
1 Original - Pond Maintenance Agreement

These are transmitted as checked below:
X As requested
For approval
For review and comment
For your use
Remarks: Ray, Here is the original of the one faxed to you last week.
We appreciate all the help we received from you and John Dorney.
Copy to:
Signed:
SWm Pridgen
Senior Project Manager
POND N1A NTENA1NCE REQUMW ENTS
Project Name: William R. Davie Middle School _ Project No.
Responsible Party: StAnl_p}t M_ Fd awls Phone No. '[phone]
Address: Halifax County Schools - P O Box 468 - Halifax, NC 27839
I. Monthly, or after every runoff producing rainfall event, whichever comes first:
A_ Inspect the trash rack; remove accumulated debris, repair/replace if it is not functioning.
Inspect and clear the orifice of any, obstructions. If a pump is used as the drawdown
mechanism, pump operation will be checked. A log of test runs of the pump will be kept
on site and made available to DEM personnel upon request,
C. Inspect the pond side slopes and grassed inlet swales; remove cash, and repair eroded
areas before the next rainfall event.
U-r-t°eAt- D. If the pond is operated with a vegetated filter, the filter will be checked for sediment
accumulation, trash accumulation, erosion and proper operation of the flow spreader
?JRpIrDFn mechanism. Repairs/ cleaning will be done as necessary.
IT. Quarterly:
A. Inspect the collection system (ie. catch basins, piping, grassed swales) for proper
functioning. Accumulated trash will be cleared from basin grates, basin bottoms, and
piping will be checked for obstructions and cleared as required.
B. Pond inlet pipes will be checked for undercutting, riprap or other energy dissipation
structures will be replaced, and broken pipes will be repaired.
M. Semi-annually:
A. Accumulated sediment from the bottom of the outlet structure will be removed.
B. The pond depth will be checked at various points. If depth is reduced to 75 % of original
`7 design depth or 3 feet whichever is greater, sediment will be removed to at least the
original design depth.
a? ?( C. Grassed swales, including the vegetated filter if applicable, will be :reseeded twice a year
as necessary.
(ro F? C? ? ?wnt
POND MAII=ANCE REQUIREgEN'TS
PAGE 2
------
IV. General:
A_ Mowing of the side slopes will be accomplished according to the season. Maximum grass
height will be 6"
B_ Cattails are encouraged along the pond perimeter, however they will be removed when they
cover more than 1/2 the surface area of the pond.
C. The orifice/pump is designed to draw down the pond in 2-5 days. If drawdown is not
accomplished in that time, the system will be checked for clogging. The source of the
clogging will be found and eliminated.
D. All components of the detention pond system will be kept in good working order. Repair
or replacement components will meet the original design specifications as per the approved
stormwater plan.
V. Special Requirements:
I, 0tan1?T M PHIJuis , hereby acknowledge that I am the financially
responsible party for maintenance of this detention pond. I will perform the maintenance as outUned
above, as pan of the Certification of Compliance with Stormwater Regulations received for this project.
Signature:
I, , a Ne.rry Pablic for the State of It) CA-4,-
County of , do hereby certify that rr as
personally appeared be ore me this / D 4 day of (Q C fSc >?L: , 19 9 , and acknowledge the
due execution of the foregoing instrument. Witness my hand and official seal,
sEA1.
My commission expires 11 )7-Z)97
DA/arl: S:1WQSISTORMWAnFORMSIO&M-POND.FOR
TNG??T CAI
'4'Ioy -e?e?PT 0-F
TIE JOHN R. McADAMS COMPANY, INC. 0 ? M?"-9k)
CONSULTING ENGINEERS 10/1.--/ 7
POST OFFICE BOX 14005
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709
[phone] FAX [phone]
October 10, 1997
RECEi VED
Mr. Ray Cox
North Carolina Department of
Environment, Health & Natural Resources
Division of Water Quality
4401 Reedy Creek Road
Raleigh, North Carolina 27607
Re: William R. Davie Middle School
Roanoke Rapids, North Carolina
DWQ #970776
DGT-96010
Dear Mr. Cox:
o" i 1 C 1997.
ENVIRnN,?NTgLX 8
This is in response to your letter of September 18, 1997 to the Halifax County
Board of Education regarding the Additional Conditions of the 401 Water Quality
Certification.
Enclosed are 2 sets of prints showing the water quality pond on the engineering
drawings, 2 copies of our Storm Water BMP Calculation Booklet and narrative,
and one DWQ - 401 Wet Detention Basin Worksheet for your review and
approval. The Maintenance Agreement is being executed by the School Board and
will be sent to you in the next few days.
Your earliest review will be greatly appreciated. Please contact us should you
have any questions.
Sincerely,
THE J R. McADAMS COMPANY, INC.
Sam Pridgen
Senior Project Manager
SP:jsh
Enclosure
cc: Mr. Mike Brooks, Doggett Architects
Mr. J. Willie Gilchrist, HCPSS
Project No. DWQ 5 / 0 2& (to be provided by DWQ)
DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a wet detention basin worksheet for each
basin, design calculations, plans and specifications showing all basin and outlet structure details, and a
fully executed operation and maintenance aggreement. An incomplete submittal package will result in a
request for additional information and will substantially delay final review and approval of the project.
1. PROJECT I:r''OKNIATION (please complete the following information):
Project Name : 1 16 NI ir;GtrS
Contact Person: V. A>hoS Phone Number: 0111 I - 5x0
For projects with multiple basins, specify which basin this. worksheet applies to: N
Basin Bottom Elevation ft. (average elevation of the floor of the basin)
Permanent Pool Elevation 233, C ft. (elevation of:the orifice invert out)
Temporary Pool Elevation. 2V - Lo ft. (elevation of the outlet structure invert in)
Permanent Pool Surface Area ?lo2?i sq. ft. (water surface area at permanent pool elevation)
Drainage Area q 1 ac. (on-site and off-site drainage to the basin)
Impervious Area ac. (on-site: and off-sire drainage to the basin)
Permanent Pool Volume 23,01oO cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 127,,5-L _cu. ft. (volume detained on top of the permanent pool)
Forebay Volume 401 cu. ft.
SA/DA used Z. (surface area to drainage area ratio)
Diameter of Orifice in. (draw down orifice diameter)
II. REQUIRED ITEMS CHECKLIST .
The following checklist outlines design requirements per the Stormwater Best Management Practices
manual (N.C. Department of Environment, Health and Natural. Resources, November 1995) and
Administrative Code Section: 15 A NCAC- 2H .1008. Initial in the space provided to indicate the
following design requirements have been, met and supporting docuinentation is attached. If a
requirement has not been met, attach an explanation of why.
Avolicants Initials
tA,'- The temporary pool conLTols runoff from the l inch storm event
SEA lff AKS SW The basin len'th to width ratio is greater than 3:1.
'bk? The basin side slopes are no steeper than 3:1.
""•l" A submerged and vegetated perimeter shelf at less than 6:1 is provided.
A -94-r Vegetation to the permanent pool elevation is specified.
An emergency drain is provided to drain the basin.
The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
The temporary pool draws down in 2 to 5 days.
1?A-C- The forebay volume is approximately equal, to 20% of the total basin volume.
bk, Sediment storage is provided in the permanent pool.
1i Access is provided for maintenance.
G -? Arr. -'f A minimum 30-foot vegetative filter is provided at the outlet.
A site specific operation and maintenance (O&NI) plan is provided.
PAL A vegetation management/mowing schedule is provided in the O&Nf plan.
7hc, Semi-annual inspections are specified in the O&M plan.
TAIII A debris check is specified in the O&Nf plan to be performed after every storm event.
DAL A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
Dke A responsible party is designated in the O&M plan.
FORM SWG100 09/9' Pap 1 of 1
REQUIRED ITEMS CHECKLIST ATTACHMENT
• The basin length to width ratio as designed is approximately 2.2:1, based on an average basin
width at normal pool of 66 feet and length at normal pool of 144 feet. Due to the existing Ov-
site layout constraints, we would be required to encroach on wetland areas to increase this
length to width ratio to 3:1.
• Vegetation on the pond to the permanent pool elevation will be grass. This is not specified
on the plans, but the entire area around and including the pond will be grassed during site
stabilization after the grading operations have ceased.
• A vegetated filter is not provided at the outlet of the pond, nor is it mentioned as a
requirement of a water quality pond in the November 1995 publication of "Stormwater Best
Management Practices" by NCDEHNR. However, the outflow from the pond will run into
existing wetland areas after being spread by a correctly designed energy dissipator (designed
to spread flow for release in non-channelized areas). These wetland areas should serve the
same purpose as a 30' vegetated filter (the wetland areas are greater than 30' long).
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DAVIE MIDDLE SCHOOL
STORMWA TER MANAGEMENT PLAN
WATER QUALITY POND FOR
401 WATER QUALITY CERTIFICATION
STORMWATER BMP CALCULATION BOOKLET
DGT-96010
OCTOBER 6, 1997
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DAVIE MIDDLE SCHOOL
STORMWATER MANAGEMENT BOOKLET
General Description
This booklet covers the stormwater quality BMP solutions for Davie Middle School in
Halifax County, North Carolina. The project includes the construction of new school facilities as
well as additional paved areas. Per comments from NC DWQ, stormwater BMPs must be
provided as an additional condition for 401 Water Quality Certification. No stormwater
detention for water quantity control is required. The on-site stormwater BMP consists of a wet
detention pond in the southeast corner of the site, just east of a proposed football field. This wet
detention pond gathers the drainage from the impervious portions of the site (asphalt parking
areas and building rooftops) for treatment and removal of 85% of the stormwater TSS. Per
telephone conversations with John Dorney and Ray Cox of DWQ on 9/30/97, runoff from the
gravel parking area west of the football field is not considered critical in the stormwater
management plan. This booklet covers only the stormwater BMP solution, and not the site
stormwater piping calculations.
Calculation Methodolozy
• All stormwater BMPs were designed per the N.C Stormwater Best Management
Practices booklet published by the NC DEHNR, Division of Water Quality.
The water quality pond was designed to remove 85% of the TSS present in the
stormwater runoff from the first one inch of rainfall. This design incorporates a
correctly sized permanent pool surface area, 1" storm runoff storage area, 12' wide
6:1 slope aquatic shelf, and a forebay at the stormwater influent area. The pond
drains the collected runoff from the 1" storm in 3.8 days through a 1.5" diameter
PVC inverted siphon. This siphon design prevents trash from plugging the
drawdown outlet.
• The water quality pond was designed to treat the runoff from the first inch of
rainfall, and safely pass design storms up to and including the 100 year event without
overtopping the containment berm.
• For calculation of the one inch rainfall storage requirement, the SCS curve number
method was utilized, employing the practice of Directly Connected Impervious Areas
(DCIAs) to realistically portray the runoff from one inch of rainfall.
• For the routing of the stormwater BMPs, the small watershed method and chainsaw
routing were employed. Tailwater conditions were modeled on the BMPs when
conditions warranted the analysis. Since this routing method was not to determine
stormwater quantity control, it should be acceptable to NC DWQ.
THE JOHN R. McADAMS COMPANY, INC.
it 1?1? P.O. Box 14005
Research Triangle Park, North Carolina 27709
L [phone] Fax [phone]
PAGE
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THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
,_- Research Triangle Park, North Carolina 27709
[phone] Fax [phone]
PAGE OF
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THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
Research Triangle Park, North Carolina 27709
-"' [phone] Fax[phone]
PAGE OF
J R M,A JOB NO WT ! ? DATE BY CHECKED BY
(Date)
CLIENT PROJECT
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THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
Il ?? Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
PAGE
J R WA JOB NOIJ?2 -9161210 DATE lo- 2?R'1 BY DV-1 CHECKED BY_
CLIENT PROJECT
SUBJECT

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THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
Research Triangle Park, North Carolina 27709
1=? [phone] Fax[phone]
?y Q PAGE OF
J R McA JOB NO. DATE 1O - Z-91 BY PAC? CHECKED BY
(Dale)
CLIENT PROJECT
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Pond
Water Quality Pond Desian Sheet
Project Name: Davie Middle School
Designer: D.A. Clark
Job Number: DGT-96010
Date: 10/2/97

Contour
feet

Stage
feet
Contour
Area
SF Average
Contour
Area
SF Incremental
Contour
Volume
CF Accumulated
Contour
Volume
CF
38.0 0.0 9620
39.0 1.0 10880 10250 10250 10250
40.0 2.0 12400 11640 11640 21890
41.0 3.0 13900 13150 13150 35040
I_
40000
1 35000
30000
v 25000
1 20000
Le
15000
10000
5000
0
Storage vs. Stage
y = 10209x'.1163
R2 = 0.9998
0.0 0.5 1.0 1.5 2.0
Stage (feet)
KS= 10209
b = 1.1163
2.5 3.0
Page 1
Pond
Calculation of Runoff Volume required for storage
The runoff to the pond for the 1" storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
From SCS Soils Survey map, predominant hydrologic soil type = D
Using basic SCS runoff methodology, with no adjustments made
to initial abstractions (0.2*S and 0.8*S).
Impervious Area, directly connected (DCIA) = 5.53 acres
@CN= 98
Other areas draining to pond (not DCIA) = 3.88 acres
@CN= 80
Runoff from DCIAs =_>
Precipitation amount = 1.0 inches
S = 0.204 inches (calculated)
Q* = 0.791 inches (calculated)
Runoff volume = 15877 CF
Runoff from non-connected areas =_>
Precipitation amount = 1.0 inches
S = 2.500 inches (calculated)
Q* = 0.083 inches (calculated)
Runoff volume = 1174 CF
Therefore, total runoff from precipitation in question = 17050 CF
This amount of runoff must be stored in the pond above normal pool elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC
siphon, the invert end of which is set at permanent pool elevation.
Page 2
Pond
Calculation of depth required for runoff storage pool (above normal pool)
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 17050 CF
Stage (above invert) associated with this storage = 1.58 feet
Therefore, depth required above normal pool for storm storage = 1.58 feet
19.00 inches
Therefore set crest of principal spillway at stage = 1.60 feet
and EL = 39.60 feet
At principal spillway crest, storm pool storage provided = 17252 F
Page 3
Below Normal Pool
Stage-Storage Function
Proiect: Davie Middle School (DGT-96010); Below normal pool for average depth only.
Average Incremental Accumulated
Contour Contour Contour Contour
Contour Stage Area Area Volume Volume
feet feet SF SF CF CF
34.00 0.00 2960
35.00 1.00 4400 3680 3680 3680
36.00 2.00 5110 4755 4755 8435
37.00 3.00 7260 6185 6185 14620
38.00 4.00 9620 8440 8440 23060
25000
20000
U.
15000
Storage vs. Stage
y = 3569.1 x131
R2 = 0.9965
ro
0 10000
N
5000
0 ?--
0.00
1.00 2.00 3.00 4.00
Stage (feet)
KS = 3569.1
b = 1.311
use 11 6 ?*C STrRA&E ft uzLT?aJ O A,1 fe""A
Imo" C- f b-0 -To pc:::r ?t rbci -, II lAW
Page 1
THE JOHN R. McADAMS COMPANY, INC.
I'
P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
PAGE OF
J R McA JOB NO. 91 ?bo1O DATE Ion 3_ H BY ?? CHECKED BY
(Date)
CLIENT PROJECT
SUBJECT
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51c MhjHmE , I- nMAL, 64TE) 1-A-SE

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THE JOHN R. McADAMS COMPANY, INC.
I o?tV Va-uM ? C??-r,?l? _ ?2 , 11 GF
I d V D?` ?D Va.AAM E ? = 128 ,? 3
P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
?y?T T PAGE
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John R. McAdams Company, Inc.
Inverted Siphon Design Sheet
D siphon =
No. siphons =
Ks =
b=
Cd siphon =
Siphon Invert
=
Volume @ Normal Pool =
Basin Invert
=
1.5 inches
1
10209
1.1163
0.60
238.00 feet
0 CF
238.00 feet
WSEL
feet Vol. Stored
c Siphon Flow
cfs Avg. Flow
cfs Incr. Vol.
c Incr. Time
sec
239.600 17252 0.073
239.450 15457 0.069 0.071 1795 25173
239.300 13683 0.066 0.068 1774 26256
239.150 11933 0.062 0.064 1750 27529
239.000 10209 0.057 0.059 1724 29057
238.850 8515 0.052 0.055 1694 30945
238.700 6856 0.047 0.050 1659 33366
238.550 5238 0.041 0.044 1618 36653
238.400 3671 0.034 0.038 1567 41530
238.250 2172 0.026 0.030 1499 50105
238.200 1693 0.022 0.024 479 20200
Drawdown Time = 3.71 days
By comparison, if calculated by the average head over the orifice (assuming
average head is half the total depth), the result would be:
Average driving head on orifice = 0.738 feet
Orifice composite loss coefficient = 0.600
X-Sectional area of 1 - 1.5" inverted siphon = 0.012 ft2
Q = 0.0507 cfs
Drawdown Time = Volume / Flowrate / 86400 (sec/day)
Drawdown Time = 3.94 da s
Page 1
Conclusion : Use 1 - 1.5" Diameter PVC Inverted Siphon to drawdown the accumulated
volume from the 1.0 " storm runoff, with a required time of about 3.8 days.
SIPHONS.XLS
Pond, 2 year
Chalnsaw Routing Method
Project Name: Davie Middle School
Project DGT-96010
Date : 1013197
Operator : DAC
Title : Pond, 2 Year Storm
Hydrograph:
Op = 32.0 CFS
Tp = 20.5 minutes
dT = 1.0 minutes
Stage-Storage
Ks = 10209.0
b = 1.12
Zo = 238.0 feet
Initial Water Level :
Zi = 238.0 feet
Computed Results
Normal Surf. Area = 0.000 acres
Max. Surf. Area = 0.287 acres
Peak Elev. = 240.24 feet
Peak Stage = 2.2 feet
Peak Outflow = 24.22 CFS
Volume Stored = 25137.7 ft3
Riser/Barrel
N=
Dr =
Cw =
Zcr =
Db =
Cd =
Bar. Invert
=
Bar. Length =
Bar. "n" _
Bar. TW Elev=
Culvert:
N=
D=
Cd =
Invert
=
Length =
Ke =
n=
Culy. TWEL =
Weir 1:
L=
Zcr =
Cw =
The John R. McAdams Company
P.O. Box 14005
Research Triangle Park, NC 27709
System Loading and Response
I
1.00 35.0
60.00 inches
3.00 30.0
239.60 feet
27.00 inches 25.0
0.60
236.20 feet 20.0
40.00 feet 1
0.013 15.0
u
238.00 feet LL
10.0
0.00 50
0.00 inches
0.00 00
?I
0.00 feet 00 100 20.0 300 40.0 50.0
0.00 feet Time (min)
0.00
0.000
0.00 feet
Weir 2:
20.00 feet L = 0.00 feet
240.50 feet Zcr = 0.00 feet
3.00 Cw = 0.00

Time
min
Inflow
cfs
Storage
ftA3
Stage
ft
Outflow
cfs
Riser(weir)
Cfs
Riser(orif.)
cfe Total
Barrel
cfe Barrel
HW Control
cfa Barrel
T;Control
cfa Culvert
HW Ctrl
Wall Culvert
TW Ctrl
(cfs)
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.2 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.7 11.3 238.0 0.00 0.00 0.00 1.09 15.75 1.09 0.00 0.00
3.0 1.7 56.0 238.0 0.00 0.00 0.00 2.23 15.84 2.23 0.00 0.00
4.0 2.9 155.7 238.0 0.00 0.00 0.00 3.53 16.00 3.53 0.00 0.00
5.0 4.5 330.5 238.0 0.00 0.00 0.00 4.94 16.26 4.94 0.00 0.00
6.0 6.3 598.8 238.1 0.00 0.00 0.00 6.45 16.62 6.45 0.00 0.00
7.0 8.4 976.8 238.1 0.00 0.00 0.00 8.03 17.09 8.03 0.00 0.00
8.0 10.6 1478.2 238.2 0.00 0.00 0.00 9.67 17.67 9.67 0.00 0.00
9.0 13.0 2113.7 238.2 0.00 0.00 0.00 11.34 18.35 11.34 0.00 0.00
10.0 15.4 2890.9 238.3 0.00 0.00 0.00 13.05 19.12 13.05 0.00 0.00
11.0 17.8 3814.1 238.4 0.00 0.00 0.00 14.78 19.98 14.78 0.00 0.00
12.0 20.2 4884.2 238.5 0.00 0.00 0.00 16.51 20.90 16.51 0.00 0.00
110 22.5 6098.6 238.6 0.00 0.00 0.00 18.23 21.87 18.23 0.00 0.00
14.0 24.7 7451.3 238.8 0.00 0.00 0.00 19.95 22.89 19.95 0.00 0.00
15.0 26.6 8933.1 238.9 0.00 0.00 0.00 21.63 23.93 21.63 0.00 0.00
16.0 28.3 10531.9 239.0 0.00 0.00 0.00 23.29 24.99 23.29 0.00 0.00
17.0 29.8 12232.5 239.2 0.00 0.00 0.00 24.91 26.04 24.91 0.00 0.00
18.0 30.8 14017.7 239.3 0.00 0.00 0.00 26.47 27.10 26.47 0.00 0.00
19.0 31.6 15868.1 239.5 0.00 0.00 0.00 27.98 28.13 27.98 0.00 0.00
20.0 32.0 17762.8 239.6 0.41 0.41 19.46 29.14 29.14 29.43 0.00 0.00
21.0 32.0 19655.3 239.8 4.16 4.16 42.10 30.11 30.11 30.80 0.00 0.00
22.0 31.6 21322.9 239.9 9.11 9.11 54.67 30.92 30.92 31.94 0.00 0.00
23.0 30.8 22671.0 240.0 13.92 13.92 62.96 31.57 31.57 32.83 0.00 0.00
24.0 29.8 23686.1 240.1 17.94 17.94 68.52 32.04 32.04 33.48 0.00 0.00
25.0 28.3 24394.7 240.2 20.93 20.93 72.14 32.36 3216 33.93 0.00 0.00
26.0 26.7 24839.2 240.2 22.88 22.88 74.31 32.56 32.56 34.20 0.00 0.00
27.0 25.1 25068.5 240.2 23.91 23.91 75.40 32.66 32.66 34.34 0.00 0.00
28.0 23.5 25137.7 240.2 24.22 24.22 75.73 32.69 32.69 34.39 0.00 0.00
29.0 22.1 25095.8 240.2 24.03 24.03 75.53 32.68 32.68 34.36 0.00 0.00
30.0 20.7 24978.6 240.2 23.51 23.51 74.98 32.62 32.62 34.29 0.00 0.00
310 19.4 24811.5 240.2 22.76 22.76 74.18 32.55 32.55 3419 0.00 0.00
32.0 18.3 24612.8 240.2 21.88 21.88 73.21 32.46 32.46 34.06 0.00 0.00
33.0 17.1 24394.9 240.2 20.94 20.94 72.14 32.36 32.36 33.93 0.00 0.00
34.0 16.1 24166.7 240.2 19.96 19.96 70.99 32.26 32.26 33.79 0.00 0.00
35,0 15.1 23934.0 240.1 18.97 18.97 69.81 32.15 32.15 33.64 0.00 0.00
Newbasin
Pond, 2 year
Time
min Inflow
cfs Storage
ft Stage
ft Outflow
cfs Riser(welr)
cfs Riser(orif.)
cfs Barrel
cfs HW Control
cfs TW Control
cfs HW Ctrl
cfs TW Ctrl
cfs
36.0 14.2 23701.0 240.1 18.01 18.01 68.60 32.04 32.04 33.49 0.00 0.00
37.0 13.3 23470.5 240.1 17.06 17.06 67.38 31.94 31.94 33.35 0.00 0.00
38.0 12.5 23244.4 240.1 16.15 16.15 66.16 31.83 31.83 33.20 0.00 0.00
39.0 11.7 230237 240.1 15.28 15.28 64.95 31.73 31.73 33.06 0.00 0.00
40.0 11.0 22809.4 240.1 14.45 14.45 63.75 31.63 31.63 32.92 0.00 0.00
41.0 10.3 22601.8 240.0 13.66 13.66 62.57 31.53 31.53 32.79 0.00 0.00
42.0 9.7 22401.1 240.0 12.91 12.91 61.40 31.44 31.44 32.66 0.00 0.00
43.0 9.1 22207.6 240.0 12.20 12.20 60.25 31.35 31.35 32.53 0.00 0.00
44.0 8.5 22021.0 240.0 11.52 11.52 59.12 31.26 31.26 32.41 0.00 0.00
45.0 8.0 21841.4 240.0 10.88 10.88 58.00 31.17 31.17 32.29 0.00 0.00
46.0 7.5 21668.6 240.0 10.28 10.28 56.91 31.09 31.09 32.17 0.00 0.00
47.0 7.1 21502.4 239.9 9.71 9.71 55.85 31.01 31.01 32.08 0.00 0.00
48.0 6.6 21342.6 239.9 9.18 9.18 54.80 30.93 30.93 31.96 0.00 0.00
Newbasin
Pond, 10 year

Chalnsaw Routing Method The John R. McAdams Company
Project Name: Davie Middle School P.O. Box 14005
Project #: DGT-96010 Research Triangle Park, NC 27709
Date : 10/3/97
Operator : DAC
Title : Pond, 10 Year Storm
Riser/Barrel : System Loading and Response
Peak Outflow = 34.57 CFS n = 0.000
Volume Stored = 29486.6 ft' Culy. TWEL = 0.00 feet
Weir 1: Weir 2:
L = 20.00 feet L = 0.00 feet
Zcr = 240.60 feet Zcr = 0.00 feet
Cw = 0.00 Cw = 0.00
Inflow
- - Outflow
r
Max. Surf. Area = 0.292 acres Invert = 0.00 feet 00 100 20.0 300 40.0 50.0
Peak Elev. = 240.59 feet Length = 0.00 feet Time (min)
Peak Stage = 2 6 feet Ke = 0.00 - -
Hydrograph: N = 1.00 ' 450
Qp = 41.6 CFS Dr = 60.00 inches 40.0
Tp = 27.2 minutes Cw = 3.00
dT = 1.0 minutes Zcr = 239.60 feet 35.0
Db = 27.00 inches

Stage-Storage :
Cd =
0.60 30.0
Ks = 10209.0 Bar. Invert = 236.20 feet 25 0
b = 1,12 Bar. Length = 40.00 feet
Zo = 238.0 feet Bar. "n" = 0.013 3 20.0
Bar. TW Elev= 238.00 feet 15.0
Initial Water Level
Zi = 238.0 feet Culvert : 10.0
N = 0.00
Computed Results : D = 0.00 inches 50
Normal Surf. Area = 0.000 acres Cd = 0.00 0.0

Time
min
Inflow
cfs
Storage
ft^3
Stage
ft
Outflow
cfa
Rlser(welr)
cfs
Riser(orlf.)
cfs Total
Barrel
cfs Barrel
HW Control
cfs Barrel
TW Control
WS) Culvert
HW Ctrl
Wall Culvert
TW Ctrl
(cfa)
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.1 0.0 236.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.6 8.3 238.0 0.00 0.00 0.00 0.95 15.75 0.95 0.00 0.00
3.0 1.2 41.5 236.0 0.00 0.00 0.00 1.95 15.81 1.95 0.00 0.00
4.0 2.2 115.6 238.0 0.00 0.00 0.00 3.09 15.94 3.09 0.00 0.00
5.0 3.4 246.5 238.0 0.00 0.00 0.00 4.33 16.14 4.33 0.00 0.00
6.0 4.8 448.9 238.1 0.00 0.00 0.00 5.67 16.42 5.67 0.00 0.00
7.0 6.4 736.7 238.1 0.00 0.00 0.00 7.08 16.80 7.08 0.00 0.00
8.0 8.3 1122.9 238.1 0.00 0.00 0.00 8.55 17.27 8.55 0.00 0.00
9.0 10.3 1618.8 238.2 0.00 0.00 0.00 10.07 17.83 10.07 0.00 0.00
10.0 12.4 2234.5 238.3 0.00 0.00 0.00 11.63 18.48 11.63 0.00 0.00
11.0 14.6 2978.4 238.3 0.00 0.00 0.00 13.23 19.21 13.23 0.00 0.00
12.0 17.0 3857.2 238.4 0.00 0.00 0.00 14.85 20.02 14.85 0.00 0.00
110 19.4 4875.9 238.5 0.00 0.00 0.00 16.50 20.89 16.50 0.00 0.00
14.0 21.8 6037.5 238.6 0.00 0.00 0.00 18.15 21.82 18.15 0.00 0.00
15.0 24.1 7343.1 238.7 0.00 0.00 0.00 19.82 22.81 19.82 0.00 0.00
16.0 26.5 8792.1 238.9 0.00 0.00 0.00 21.48 23.83 21.48 0.00 0.00
17.0 28.8 10381.6 239.0 0.00 0.00 0.00 23.14 24.89 23.14 0.00 0.00
18.0 30.9 12107.2 239.2 0.00 0.00 0.00 24.79 25.97 24.79 0.00 0.00
19.0 32.9 13962.5 239.3 0.00 0.00 0.00 26.43 27.07 26.43 0.00 0.00
20.0 34.8 15939.3 239.5 0.00 0.00 0.00 28.04 28.17 28.04 0.00 0.00
21.0 36.5 18028.1 239.7 0.77 0.77 23.98 29.28 29.26 29.63 0.00 0.00
22.0 38.0 20171.4 239.8 5.56 5.56 46.36 30.36 30.36 31.16 0.00 0.00
23.0 39.2 22115.5 240.0 11.86 11.86 59.69 31.30 31.30 32.47 0.00 0.00
24.0 40.2 23755.8 240.1 18.23 18.23 68.89 32.07 32.07 33.53 0.00 0.00
25.0 40.9 250737 240.2 23.93 23.93 75.43 32.67 32.67 34.35 0.00 0.00
26.0 41.4 26093.6 240.3 28.66 28.66 80.10 33.12 33.12 34.97 0.00 0.00
27.0 41.6 26857.9 240.4 32.38 32.38 83.42 33.45 33.45 35.42 0.00 0.00
28.0 41.5 27411.0 240.4 33.69 35.15 85.74 33.69 33.69 35.75 0.00 0.00
29.0 41.2 27880.1 240.5 33.89 37.55 87.65 33.89 33.89 36.02 0.00 0.00
30.0 40.5 28315.6 240.5 34.08 39.83 89.38 34.08 34.08 36.27 0.00 0.00
31.0 39.6 28702.1 240.5 34.24 41.88 90.90 34.24 34.24 36.49 0.00 0.00
32.0 38.5 29025.3 240.5 34.38 43.62 92.14 34.38 34.38 36.68 0.00 0.00
33.0 37.1 29271,6 240.6 34.48 44.97 93.07 34.48 34.48 36.81 0.00 0.00
34.0 35.5 29429,0 240.6 34.55 45.83 93.67 34.55 34.55 36.90 0.00 0.00
350 33.9 29486.6 240.6 34.57 46.15 93.88 34.57 34.57 36.94 0.00 0.00
Newbasin
Pond, 10 year
Time
min Inflow
cfs Storage
f A3 Stage
tt Outflow
cfa Riser(weir)
cfs Riser(orif.)
cfs Barrel
cfs HW Control
cfa TW Control
cfs HW Ctrl
cfs TW Ctrl
cfs
36.0 32.3 29445.8 240.6 34.55 45.92 93.73 34.55 34.55 36.91 0.00 0.00
37.0 30.8 29311.2 240.6 34.50 45.18 93.22 34.50 34.50 36.84 0.00 0.00
38.0 29.4 29089.4 240.6 34.41 43.97 92.38 34.41 34.41 36.71 0.00 0.00
39.0 28.0 28786.9 240.5 34.28 42.34 91.22 34.28 34.28 36.54 0.00 0.00
40.0 26.7 28409.9 240.5 34.12 40.33 89.76 34.12 34.12 36.32 0.00 0.00
41.0 25.4 27964.0 240.5 33.93 37.99 87.99 33.93 33.93 36.07 0.00 0.00
42.0 24.3 27454.7 240.4 33.71 35.37 85.92 33.71 33.71 35.77 0.00 0.00
43.0 23.1 26887.3 240.4 32.52 32.52 83.54 33.47 33.47 35.44 0.00 0.00
44.0 22.0 26323.4 240.3 29.76 29.76 81.11 33.22 33.22 35.10 0.00 0.00
45.0 21.0 25860.2 240.3 27.56 27.56 79.06 33.02 33.02 34.83 0.00 0.00
46.0 20.0 25467.7 240.3 25.73 25.73 77.27 32.84 32.84 34.59 0.00 0.00
47.0 19.1 25126.0 240.2 24.17 24.17 75.67 32.69 32.69 34.38 0.00 0.00
48.0 18.2 24821.8 240.2 22.81 22.81 74.22 32.55 32.55 34.19 0.00 0.00
Newbasin
Pond, 100 year
Chainsaw Routing Method
Project Name: Davie Middle School
Project # : DGT-96010
Date : 10/3/97
Operator : DAC
Title : Pond, 100 Year Storm
Riser/Barrel
Hydrograph: N =
Qp = 57.2 CFS Dr=
Tp = 32.6 minutes Cw =
dT = 1.0 minutes Zcr =
Db =
Stage-Storage : Cd =
Ks = 10209.0 Bar. Invert
=
b = 1.12 Bar. Length =
Zo = 238.0 feet Bar. "n" =
Bar. TW Elev=
Initial Water Level
Zi = 238.0 feet Culvert:
N=
Computed Results : D =
Normal Surf. Area = 0.000 acres Cd =
Max. Surf. Area = 0.298 acres Invert
=
Peak Elev. = 241.05 feet Length =
Peak Stage = 3.0 feet Ke =
Peak Outflow = 54.74 CFS n =
Volume Stored = 35385.2 ft3 Cuty. TWEL =
Weir 1:
L=
Zcr
Cw =
The John R. McAdams Company
P.O. Box 14005
Research Triangle Park, NC 27709
System Loading and Response
1.00 soo
60.00 inches
3.00 50.0
239.60 feet
27.00 inches 40.0
0.60
236.20 feet
40.00 feet 30,0
0.013
238.00 feet 20.0
I
0.00 10.0
0.00 inches
0.00 00
Inflow
- - Outflow
0.00 feet 0.0 10.0 20.0 30.0 40.0 50.0 ',.
0.00 feet Time (min)
0.00 -- -
0.000
0.00 feet
Weir 2:
20.00 feet L = 0.00 feet
240.60 feet Zcr = 0.00 feet
3.00 Cw = 0.00

Time
min
Inflow
cfa
Storage
ftA3
Stage
(ft)
Outflow
cfs
Riser(weir)
cfs
Riser(orif.)
cfa Total
Barrel
cfa Barrel
HW Control
cfa Barrel
T; "Control
cfs Culvert
HW Ctrl
cfs Culvert
TW Ctrl
cfs
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.1 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.5 8.0 238.0 0.00 0.00 0.00 0.93 15.75 0.93 0.00 0.00
3.0 1.2 39.7 238.0 0.00 0.00 0.00 1.91 15.81 1.91 0.00 0.00
4.0 2.1 110.9 238.0 0.00 0.00 0.00 3.03 15.93 3.03 0.00 0.00
5.0 3.3 236.9 238.0 0.00 0.00 0.00 4.26 16.12 4.26 0.00 0.00
6.0 4.6 432.2 238.1 0.00 0.00 0.00 5.57 16.40 5.57 0.00 0.00
7.0 6.3 711.2 238.1 0.00 0.00 0.00 6.96 16.77 6.98 0.00 0.00
8.0 8.1 1087.0 238.1 0.00 0.00 0.00 8.42 17.22 8.42 0.00 0.00
9.0 10.1 1572.2 238.2 0.00 0.00 0.00 9.94 17.78 9.94 0.00 0.00
10.0 12.3 2178.2 238.3 0.00 0.00 0.00 11.50 18.42 11.50 0.00 0.00
11.0 14.6 2915.2 238.3 0.00 0.00 0.00 13.10 19.15 13.10 0.00 0.00
12.0 17.1 3792.4 238.4 0.00 0.00 0.00 14.74 19.96 14.74 0.00 0.00
13.0 19.7 4817.5 238.5 0.00 0.00 0.00 16.41 20.84 16.41 0.00 0.00
14.0 22.3 5996.9 238.6 0.00 0.00 0.00 18.10 21.79 18.10 0.00 0.00
15.0 25.0 7335.7 238.7 0.00 0.00 0.00 19.81 22.80 19.81 0.00 0.00
16.0 27.8 8837.3 238.9 0.00 0.00 0.00 21.53 23.88 21.53 0.00 0.00
17.0 30.5 10503.7 239.0 0.00 0.00 0.00 23.26 24.97 23.26 0.00 0.00
18.0 33.3 12335.3 239.2 0.00 0.00 0.00 25.00 26.11 25.00 0.00 0.00
19.0 36.0 14331.2 239.4 0.00 0.00 0.00 26.74 27.28 26.74 0.00 0.00
20.0 38.6 16488.7 239.5 0.00 0.00 0.00 28.47 28.47 28.47 0.00 0.00
21.0 41.1 188016 2391 2.17 2.17 33.87 29.68 29.68 30.19 0.00 0.00
22.0 43.5 21140.6 239.9 8.51 8.51 53.44 30.84 30.84 31.82 0.00 0.00
23.0 45.8 23241.8 240.1 16.14 16.14 66.15 31.83 31.83 33.20 0.00 0.00
24.0 47.9 25021.7 240.2 23.70 23.70 75.18 32.64 32.64 34.32 0.00 0.00
25.0 49.9 26475.4 240.3 30.50 30.50 81.78 33.29 33.29 35.20 0.00 0.00
26.0 51.6 27637.4 240.4 33.79 36.30 86.66 33.79 33.79 35.88 0.00 0.00
27.0 53.1 28706.4 240.5 34.24 41.91 90.91 34.24 34.24 36.49 0.00 0.00
28.0 54.4 29839.9 240.6 34.82 48.11 95.19 34.72 34.72 37.13 0.00 0.00
29.0 55.5 31017.0 240.7 37.27 54.82 99.43 35.20 35.20 37.78 0.00 0.00
30.0 56.3 32110.4 240.8 40.66 61.28 103.19 35.64 35.64 38.37 0.00 0.00
31.0 56.9 33048.9 240.9 44.17 66.99 106.30 36.02 36.02 38.87 0.00 0.00
32.0 57.2 33810.3 240.9 47.35 71.74 108.76 36.32 36.32 39.27 0.00 0.00
33,0 57.2 34398.6 241.0 49.99 75.47 110.61 36.54 36.54 39.57 0.00 0.00
34.0 56.9 34830.0 241.0 52.02 78.25 111.95 36.71 36.71 39.80 0.00 0.00
35.0 56.4 35125.4 241.0 53.45 80.16 112.86 36.82 36.82 39.95 0.00 0.00
Newbasin
Pond, 100 year
Time
min Inflow
cfa Storage
ft"3 Stage
ft Outflow
cfs Riser(weir)
cfs Riser(orif.)
cfs Barrel
cis HW Control
cfs TW Control
cfs HW Ctrl
cfs TW Ctrl
cis
36.0 55.7 35304.7 241.0 54.34 81.33 113.40 36.89 36.89 40.04 0.00 0.00
37.0 54.7 35385.2 241.0 54.74 81.86 113.65 36.92 36.92 40.08 0.00 0.00
38.0 53.4 35380.9 241.0 54.72 81.83 113.63 36.92 36.92 40.08 0.00 0.00
39.0 51.9 35302.7 241.0 54.33 81.32 113.40 36.89 36.89 40.04 0.00 0.00
40.0 50.2 35158.9 241.0 53.62 80.36 112.96 36.84 36.84 39.96 0.00 0.00
41.0 48.4 34955.9 241.0 52.62 79.06 112.34 36.76 36.76 39.86 0.00 0.00
42.0 46.5 34702.3 241.0 51.41 77.42 111.55 36.66 36.66 39.73 0.00 0.00
43.0 44.7 34408.2 241.0 50.03 75.54 110.64 36.55 36.55 39.58 0.00 0.00
44.0 42.9 34087.6 240.9 48.57 73.49 109.63 36.42 36.42 39.41 0.00 0.00
45,0 41.3 33749.6 240.9 47.09 7116 108.56 36.29 36.29 39.24 0.00 0.00
46.0 39.6 33400.3 240.9 45.60 69.17 107.44 36.15 36.15 39.06 0.00 0.00
47.0 38.1 33043.1 240.9 44.15 66.96 106.28 36.01 36.01 36.87 0.00 0.00
48.0 36.6 32680.3 240.8 42.74 64.73 105.09 35.87 35.87 38.68 0.00 0.00
Newbasin
THE JOHN R. McADAMS COMPANY, INC.
3g ? FMS I ?o Ph-:0
P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
TM- _ o -1 7? PAGE
D,12__ CHECKED BY _
J R McA JOB NO I/? '1(00 DATE I d7 ??1 BY
PROJECT
CLIENT
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(Date)
OF
THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
u? Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
PAGE OF
J R McA JOB NO. 1a'9T' jk.C DATE BY VAS CHECKED BY
(Date)
CLIENT PROJECT
SUBJECT
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NRCD Land Quality Section
Pipe Design
Entering the following values wi11 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 : 27.95
slope S in x : .65
pipe diameter D in in. : 30
Manning number n : 0.013
- Dissipator , Pipe or Quit (D P or Q) -
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 2.50
Out)et velocity (fps) 7.56
Apron length (ft) 15.00
AVG DIAM STOVE 7HICIOVESS
(inches) LASS (inches)
3 A 9
y 6 B 22
13 B or 1 22
23 2 27
- Dissipator ,Pipe or QLit (D P or Q) -
? I
USE ?GOar 0,e,
P- hP
15??x q,Wx zz " 11iK.-
Flow depth (ft) = 1.76
Cutlet velocity (fps) = 7.559
To c oft.. '.
•• W 0. I. +Do
= 0.4 (Ie)+Z,S
8.?
G ->-D
NRCD Land Qjality 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.
OLATl.??
flow Q in cfs : 39.22 Flow depth (ft) = 2.50
slope S in X : .5 Outlet velocity (fps) = 7.990
pipe diameter D in in. : 30
Manning number n : 0.073
Pipe flow condition. V=Q/Apipe.
Should double check by another method!!
'pry PAIF- To
- Dissipator , Pipe or Quit (D P or Q) -
W _ 1L+ D0
IJ +
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 2.50
Cutlet velocity (fps) 7.99
Apron length (ft) 75.00
AYG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
6 B 22 a
13 B or 1 22
23 2 27
- Oissipator , Pipe or Quit (D P or Q) -
USA GL e ? rAP- f AP
16 Lx I P ??< ZZ `? 1TW--
t
U
DAVIE MIDDLE SCHOOL
STORMWA TER MANAGEMENT PLAN
WATER QUALITY POND FOR
401 WATER QUALITY CERTIFICATION
STORMWATER BMP CALCULATION BOOKLET
DGT-96010
OCTOBER 6, 1997
.10
CAR
f SEAL '
15391
?U
DAVIE MIDDLE SCHOOL
STORMWATER MANAGEMENT BOOKLET
General Description
This booklet covers the stormwater quality BMP solutions for Davie Middle School in
Halifax County, North Carolina. The project includes the construction of new school facilities as
well as additional paved areas. Per comments from NC DWQ, stormwater BMPs must be
provided as an additional condition for 401 Water Quality Certification. No stormwater
detention for water quantity control is required. The on-site stormwater BMP consists of a wet
detention pond in the southeast corner of the site, just east of a proposed football field. This wet
detention pond gathers the drainage from the impervious portions of the site (asphalt parking
areas and building rooftops) for treatment and removal of 85% of the stormwater TSS. Per
telephone conversations with John Dorney and Ray Cox of DWQ on 9/30/97, runoff from the
gravel parking area west of the football field is not considered critical in the stormwater
management plan. This booklet covers only the stormwater BMP solution, and not the site
stormwater piping calculations.
Calculation Methodolory
• All stormwater BMPs were designed per the N.C Stormwater Best Management
Practices booklet published by the NC DEHNR, Division of Water Quality.
The water quality pond was designed to remove 85% of the TSS present in the
stormwater runoff from the first one inch of rainfall. This design incorporates a
correctly sized permanent pool surface area, I" storm runoff storage area, 12' wide
6:1 slope aquatic shelf, and a forebay at the stormwater influent area. The pond
drains the collected runoff from the I" storm in 3.8 days through a 1.5" diameter
PVC inverted siphon. This siphon design prevents trash from plugging the
drawdown outlet.
• The water quality pond was designed to treat the runoff from the first inch of
rainfall, and safely pass design storms up to and including the 100 year event without
overtopping the containment berm.
• For calculation of the one inch rainfall storage requirement, the SCS curve number
method was utilized, employing the practice of Directly Connected Impervious Areas
(DCIAs) to realistically portray the runoff from one inch of rainfall.
• For the routing of the stormwater BMPs, the small watershed method and chainsaw
routing were employed. Tailwater conditions were modeled on the BMPs when
conditions warranted the analysis. Since this routing method was not to determine
Stormwater quantity control, it should be acceptable to NC DWQ.

e
THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
?r-? ? PAGE
?3 I1 BY CHECKED BY
J R McA JOB NO.1421-p DATE 10 0
CLIENT PROJECT
SUBJECT
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Tewr. U ?. = STS wla ITT'
OF
• THE JOHN R. McADAMS COMPANY, INC.
I P ,O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
PAGE OF
J R McA JOB NO. IY?T g1,2C1 DATE 10 - 3 - '171 BY t)W- CHECKED BY
(Date)
CLIENT PROJECT
SUBJECT
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9f-(-W Vr-T- DiPPW GAWAv-,I-UV 5Ter- CU0104F5, 5PCF+ CLAM42
AM-A:1-4eO 10 Mnt-*? Rises $•j 2 - 4 "X 1/¢ a Cow
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Bnah s?ru. ? ??y s'vac? ; ?4 13r?s ?13 0?
SP??? ?? M ?I?2 ? ??u SPPGE = 11,(0
44 pt??,e
• THE JOHN R. McADAMS COMPANY, INC.
III P.O. Box 14005
Research Triangle Park, North Carolina 27709
• -"'° [phone] Fax[phone]
y Q /? T PAGE OF
J R M(-.A JOB NO. ???T `??? DATE I0-7 BY V CHECKED BY.
(Date)
CLIENT PROJECT
SUBJECT ?-C' Te-6 CX?3
??t U 1?E
INIur DP-/4i0 ?w fit- ; Ti?? IMPe"IcLAS AaGiS To OkA Vr--T CMPT)LvJ
'54TS 5,;,+1, -t -IFE5
,S(,+P-Fib 5c::4 L- ANN f ? '?kAeTii-z Scat- _ ? - Si Lxq CLAI w /
Re-;e,' = V USE VCF- CfJ CM..F.I. -FICN)
VRx, NW-,6 Ao-? To Ft7jQ
• DA ?cM ? IMF l ?"1" ' STceMwR-Tt? CAt?S?
cov-*?/ / --) C?-- 0,40 ic?j =- 80
IMps"IwS =?D 0'= 0'9S/ 61 -- q6
; . V ?I - G,-57 k C, C = o. Sq / CA = °I`,?
• T)A Ffc?A bA 0 = S lo k- P, ??, I m?, (9> S1rCp1mwA1F4
210k, e G= D,c??Gti1= 8(0
t4EwIQ
• > D?P.e - To Fa-v A2= 1,34k, @ 0% IMF
?A attT = I --zA At, @ 0-=0,4o /Clki - Sv
T lei -rte Fb-v DA - q, d I A, ? c = 0,-1-6 /0? - Ro
r V ?0
?O optx\I 10-r" =-
THE JOHN R. McADAMS COMPANY, INC.
rl? P.O. Box 14005
?, s==== Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
/? / PAGE
J R McA JOB NO. L:u.f-?_IkQ1e2 DATE 10-Z-11 BY VAy CHECKED BY_
CLIENT PROJECT
SUBJECT
_Rr> - 1 P-Af?E AE74/` EEMt>
DA- = q, 41 k- 9, ?o I M 1r1A
b ;;rrl 3
1.31 I
Fc? OC2?1 TSS v?Ati 6FFi0Rwq
5 o?a -Z. oo
5?,??l0 2. s I?.:r1
60% Z,31
0. ZZ k-,
ea Ilw ' ct(020 ,?r- 0
D I t1 STOW ?-'o -.r ?- u? B ?
c? CAuuln1'tta?, Ser:_ wAT22- QVA_,TLj Pa-O CMr SN P',
I I t s-roeM q0 S-raeAlne P- ',o = 11 oSO CF
I If STcem P/o ?-:Froe/vc PDnvt pt jv ?-IZSZ CF O
DPr = q'* A<, @ C° 0,13' c& = go
TG = I o. 4 m I o ( F f; 5-ram vex Cm-c--,)

(Date)
OF
* : =OF CuRvc- C?,c, e'2- FdF zze Wta5 *4?i)
THE JOHN R. McADAMS COMPANY, INC.
l??ll P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax [phone]
J R McA JOB NO. DATE 10 - Z? 91 BY VrC?
CLIENT PROJECT
SUBJECT
QZ = Co,-r3 ?.c?'''l? ?Cq. ?? _ 3z. o (-F-
010 = (o.13K(?.US (Nl?+? J1?, 1 /?G' _ I. !o GFS
PAGE
CHECKED BY _
cis
_ 33'%?Xq A Ac-) - 57,Z
S= 1? -lo = In

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ley
T'7 . Zo, ; plo
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,c,
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I I( S"fc2M r-/0 p(yAwpa ? 71 M E
Cfh..r,c,?l.A'1I L7-?S 5th I y'?eCT-'FO S PHUv VU5'C:43 SHEET,
(Date)
p41-, iarle, - 3,84
P(11 )LIAIr, =')jb
1y /?y VI ? >? p(>-0 mu--,r ?w^?' i l,lh Y F f-0,4o I M, 5TCgr\,1 l'C-
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OF
Pond
Water Quality Pond Design Sheet
Project Name: Davie Middle School
Designer: D.A. Clark
Job Number: DGT-96010
Date: 10/2/97

Contour
feet

Stage
feet
Contour
Area
SF Average
Contour
Area
SF Incremental
Contour
Volume
CF Accumulated
Contour
Volume
CF
38.0 0.0 9620
39.0 1.0 10880 10250 10250 10250
40.0 2.0 12400 11640 11640 21890
41.0 3.0 13900 13150 13150 35040
Storage vs. Stage
40000
35000
30000
v 25000
20000
15000
10000
5000
0
y = 10209X1.1163
R2 = 0.9998
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Stage (feet)
Ks = 10209
b = 1.1163
Page 1
Pond
Calculation of Runoff Volume required for storage
The runoff to the pond for the 1" storm detention requirement is calculated using the SCS curve
number method. Impervious areas that directly enter the pond are counted as Directly Connected
Impervious Areas (DCIAs). No infiltration calculation will be provided for these areas. Areas
not directly connected will be accounted for in a composite curve number.
From SCS Soils Survey map, predominant hydrologic soil type = D
Using basic SCS runoff methodology, with no adjustments made
to initial abstractions (0.2'S and 0.8"S).
Impervious Area, directly connected (DCIA) _
@CN=
Other areas draining to pond (not DCIA) _
@CN=
Runoff from DCIAs =_>
x,1'44 Precipitation amount =
i, S =
Q• _
Runoff volume =
Runoff from non-connected areas =_>
Precipitation amount =
S=
Q• _
Runoff volume =
5.53 acres
98 ,c
3.88 acres w
80
1.0 inches
0.204 inches (calculated)
0.791 inches (calculated)
15877 CF A"- o
1.0 inches
2.500 inches (calculated)
0.083 inches (calculated)
1174 CF
Therefore, total runoff from precipitation in question = 7050 CF o"'
This amount of runoff must be stored in the pond above normal pool, elevation,
and be released in a period of two (2) to five (5) days, by an inverted PVC T
siphon, the invert end of which is set at permanent pool elevation.
4 GF
LIKC
lJ,.ou A
I ell
?L s ,FWD
+11
Page 2 ogto V,
r<SA ??
Pond
Calculation of depth required for runoff storage pool (above normal pool)
Normal pool depth (above invert) = 0.00 feet
Storage provided at permanent pool depth = 0 CF (calculated)
Total storage required for normal + storage pool = 17050 CF
Stage (above invert) associated with this storage = 1.58 feet
Therefore, depth required above normal pool for storm storage = 1.58 feet
19.00 inches
Therefore set crest of principal spillway at stage = 1.60 feet
and EL = 39.60 feet
At principal spillway crest, storm pool storage provided = 17252 F
Page 3
Below Normal Pool
Stage-Storage Function
Project: Davie Middle School (DGT-96010); Below normal pool for average depth only.
Average Incremental Accumulated
Contour Contour Contour Contour
Contour Stage Area Area Volume Volume
feet feet SF SF CF (CF)
34.00 0.00 2960
35.00 1.00 4400 3680 3680 3680
36.00 2.00 5110 4755 4755 8435
37.00 3.00 7260 6185 6185 14620
38.00 4.00 9620 8440 8440 23060
25000
20000
LL
U 15000
Storage vs. Stage
y = 3569.1x131
RZ = 0.9965
m
o,
o 10000
5000
0 H
0.00
1.00 2.00 3.00 4.00
Stage (feet)
KS = 3569.1
b = 1.311
-To Aoen At, ?pmt? , t t5?p
AEG. Deg)4 CAc.uacA-riaJ,
Page 1
THE JOHN R. McADAMS COMPANY, INC.
P.O. Box 14005
Research Triangle Park, North Carolina 27709
- [phone] Fax[phone]
PAGE OF
J R MA JOB NO. ?T? 1bo1? DATE BY Vfe-- CHECKED BY
(Date)
CLIENT PROJECT
SUBJECT
Aro I - ?o114 T?aJ C•1?k[LS
of >Y?S?-?G = Z3(o. 20 Cis of ?trAo?sic?>
ice ce 7-I- = Z?, coo Cap ?i? Ec ( -rlcn>>
44 = 3 • d ter.
T iaoM NG PeoOU cm Ch rr? --->

4. o' BPtASX5 I • 61' ? Tjpnj;'A> = V5
PGF , Ca re Vaw rAE = ee, 4 cF
Ao lAt?r C?-_ Wes. DI ?R,?G ---->
N co??e? = S5, ?? 7o AL = I ZZ, Zo cr- ?
6,1 vAlue- 1 P51 ?` 2 = 0(0.140 CF Dr-?
(,?sl-. cF D?SP? wig- _ -1 Cols ?
GK-- 1 S 7o 5A FA?Tc NCO P>-7-7o LS Cz),- -TF_ Mzet-
?voyA ?_T• (ter - ) ?o?cF - (c2 •? PcF = ??, (? P?F
I N?-i-? o "&- z fiv-Tcie- = 7(0 , Z P?F
o . LAS5 (o. 0 of Gc>? ) o $ASE (H h-_;)
DIArAone? CF 6c?? WE; = eYoi) ( -7. I1 F`) = 40.34 5F
Aoo 2't Tfl &jv,0W r A% T-nc40e_'-6
?v 73 CF Cc? 7E A00w
THE JOHN R. McADAMS COMPANY, INC.
t6-T- PAGE
SUBJECT
P.O. Box 14005
Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
?rCV BY-
J R McA JOB NO. (? DATE Io -3 By
CHECKED
PROJECT
Tol?`tl? V i"i e7 &z ,17 GF
(Date)
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John R. McAdams Company, Inc.
Inverted Siphon Design Sheet
D siphon =
No. siphons =
Ks =
b=
Cd siphon =
Siphon Invert
=
Volume @ Normal Pool =
Basin Invert
=
1.5 inches
1
10209
1.1163
0.60
238.00 feet
0 CF
238.00 feet
WSEL
feet Vol. Stored
c Siphon Flow
cfs Avg. Flow
cfs Incr. Vol.
c Incr. Time
sec
239.600 17252 0.073
239.450 15457 0.069 0.071 1795 25173
239.300 13683 0.066 0.068 1774 26256
239.150 11933 0.062 0.064 1750 27529
239.000 10209 0.057 0.059 1724 29057
238.850 8515 0.052 0.055 1694 30945
238.700 6856 0.047 0.050 1659 33366
238.550 5238 0.041 0.044 1618 36653
238.400 3671 0.034 0.038 1567 41530
238.250 2172 0.026 0.030 1499 50105
238.200 1693 0.022 0.024 479 20200
Drawdown Time = 3.71 days
By comparison, if calculated by the average head over the orifice (assuming
average head is half the total depth), the result would be:
Average driving head on orifice = 0.738 feet
Orifice composite loss coefficient = 0.600
X-Sectional area of 1 - 1.5" inverted siphon = 0.012 ftz
Q = 0.0507 cfs
Drawdown Time = Volume / Flowrate / 86400 (sec/day)
Drawdown Time = 3.94 days
Page 1
Conclusion : Use 1 - 1.5" Diameter PVC Inverted Siphon to drawdown the accumulated
volume from the 1.0 " storm runoff, with a required time of about 3.8 days.
SIPHONS.XLS
Pond, 2 year
Chalnsaw Routing Method The John R. McAdams Company
Project Name: Davie Middle School P.O. Box 14005
Project DGT-96010 Research Triangle Park, NC 27709
Date : 10/3/97
Operator : DAC
Title : Pond, 2 Year Storm
Riser/Barrel : System Loading and Response
Hydrograph: N = 1.00 35.0
Qp = 32.0 CFS Dr = 60.00 inches
Tp = 20.5 minutes Cw = 3.00 30.0
dT = 1.0 minutes Zcr = 239.60 feet
Db = 27.00 inches 25.o
Stage-Storage : Cd = 0.60
Ks = 10209.0 Bar. Invert = 236.20 feet 20.0
b = 1.12 Bar. Length = 40.00 feet
Zo = 238.0 feet Bar. "n" = 0.013 0 150
Bar. TW Elev= 238.00 feet
Initial Water Level : 10.0
Zi = 238.0 feet Culvert:
N = 0.00 50
Computed Results : D = 0.00 inches
Normal Surf. Area = 0.000 acres Cd = 0.00 00
Inflow
Outflow

Max. Surf. Area = 0.287 acres Invert = 0.00 feet 00
Peak Elev. = 240.24 feet Length = 0.00 feet
Peak Stage = 2.2 feet Ke = 0.00
Peak Outflow = 24.22 US n = 0.000
Volume Stored = 25137.7 ft' Culy. TWEL = 0.00 feet
Weir 1:
L = 20.00 feet
Zcr = 240.50 feet
Cw = 3.00
10.0 20.0 30.0 40.0 50.0
Time (min)
Weir 2:
L = 0.00 feet
Zcr = 0.00 feet
Cw = 0.00

Time
min
Inflow
cfs
Storage
ft"3
Stage
ft
Outflow
cfa
Riser(weir)
cfs
Riser(orif.)
cfa Total
Barrel
cfs Barrel
HW Control
cfs Barrel
TW Control
cfs Culvert
HW Ctrl
cfs Culvert
TW Ctrl
cfs
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.2 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.7 11.3 238.0 0.00 0.00 0.00 1.09 15.75 1.09 0.00 0.00
3.0 1.7 58.0 238.0 0.00 0.00 0.00 2.23 15.84 2.23 0.00 0.00
4.0 2.9 155.7 238.0 0.00 0.00 0.00 3.53 16.00 3.53 0.00 0.00
5.0 4.5 330.5 238.0 0.00 0.00 0.00 4.94 16.26 4.94 0.00 0.00
6.0 6.3 598.8 238.1 0.00 0.00 0.00 6.45 16.62 6.45 0.00 0.00
7.0 8.4 976.8 238.1 0.00 0.00 0.00 8.03 17.09 8.03 0.00 0.00
8.0 10.6 1478.2 238.2 0.00 0.00 0.00 9.67 17.67 9.67 0.00 0.00
9.0 13.0 2113.7 238.2 0.00 0.00 0.00 11.34 18.35 11.34 0.00 0.00
10.0 15.4 2890.9 238.3 0.00 0.00 0.00 13.05 19.12 13.05 0.00 0.00
11.0 17.8 3814.1 238.4 0.00 0.00 0.00 14.78 19.98 14.78 0.00 0.00
12.0 20.2 4884.2 238.5 0.00 0.00 0.00 16.51 20.90 16.51 0.00 0.00
13.0 22.5 6098.6 238.6 0.00 0.00 0.00 18.23 21.87 18.23 0.00 0.00
14.0 24.7 7451.3 238.8 0.00 0.00 0.00 19.95 22.89 19.95 0.00 0.00
15.0 26.6 8933.1 238.9 0.00 0.00 0.00 21.63 23.93 21.63 0.00 0.00
16.0 28.3 10531.9 239.0 0.00 0.00 0.00 23.29 24.99 23.29 0.00 0.00
17.0 29.8 12232.5 239.2 0.00 0.00 0.00 24.91 26.04 24.91 0.00 0.00
18.0 30.8 14017.7 239.3 0.00 0.00 0.00 26.47 27.10 26.47 0.00 0.00
19.0 31.6 15868.1 239.5 0.00 0.00 0.00 27.98 28.13 27.98 0.00 0.00
20.0 32.0 17762.8 239.6 0.41 0.41 19.46 29.14 29.14 29.43 0.00 0.00
21.0 32.0 19655.3 239.8 4.16 4.16 42.10 30.11 30.11 30.80 0.00 0.00
22.0 31.6 21322.9 239.9 9.11 9.11 54.67 30.92 30.92 31.94 0.00 0.00
23.0 30.8 22671.0 240.0 13.92 13.92 62.96 31.57 31.57 32.83 0.00 0.00
24.0 29.8 23686.1 240.1 17.94 17.94 68.52 32.04 32.04 33.48 0.00 0.00
25.0 28.3 24394.7 240.2 20.93 20.93 72.14 32.36 32.36 33.93 0.00 0.00
26.0 26.7 24839.2 240.2 22.88 22.88 74.31 32.56 32.56 34.20 0.00 0.00
27.0 25.1 25068.5 240.2 23.91 23.91 75.40 32.66 32.66 34.34 0.00 0.00
28.0 23.5 25137.7 240.2 24.22 24.22 75.73 32.69 32.69 34.39 0.00 0.00
29.0 22.1 25095.8 240.2 24.03 24.03 75.53 32.68 32.68 34.36 0.00 0.00
30.0 20.7 24978.6 240.2 23.51 23.51 74.98 32.62 32.62 34.29 0.00 0.00
31.0 19.4 24811.5 240.2 22.76 22.76 74.18 32.55 32.55 34.19 0.00 0.00
32.0 18.3 24612.8 240.2 21.88 21.88 73.21 32.46 32.46 34.06 0.00 0.00
33.0 171 24394.9 240.2 20.94 20.94 72.14 32.36 32.36 33.93 0.00 0.00
34.0 16.1 241667 240.2 19.96 19.96 70.99 32.26 32.26 33.79 0.00 0.00
350 15.1 23934.0 2401 18.97 18.97 69.81 32.15 32.15 33.64 0.00 0.00
Newbasin
Pond, 2 year
Time
min Inflow
cfs Storage
k^3 Stage
ft Outflow
cfs Riser(weir)
cfs Riser(orif.)
cfs Barrel
cfs HW Control
cfs TW Control
cfs HW Ctrl
cfa TW Ctrl
cfa
36.0 14.2 23701.0 240.1 18.01 18.01 68.60 32.04 32.04 33.49 0.00 0.00
37.0 13.3 23470.5 240.1 17.06 17.06 67.38 31.94 31.94 33.35 0.00 0.00
38.0 12.5 23244.4 240.1 16.15 16.15 66.16 31.83 31.83 33.20 0.00 0.00
39.0 11.7 23023.7 240.1 15.26 15.28 64.95 31.73 31.73 33.06 0.00 0.00
40.0 11.0 22809.4 240.1 14.45 14.45 63.75 31.63 31.63 32.92 0.00 0.00
41.0 10.3 22601.8 240.0 13.66 13.66 62.57 31.53 31.53 32.79 0.00 0.00
42.0 9.7 22401.1 240.0 12.91 12.91 61.40 31.44 31.44 32.66 0.00 0.00
43.0 9.1 22207.6 240.0 12.20 12.20 60.25 31.35 31.35 32.53 0.00 0.00
44.0 8.5 22021.0 240.0 11.52 11.52 59.12 31.26 31.26 32.41 0.00 0.00
45.0 8.0 21841.4 240.0 10.88 10.88 58.00 31.17 31.17 32.29 0.00 0.00
46.0 7.5 21668.6 240.0 10.28 10.28 56.91 31.09 31.09 32.17 0.00 0.00
47.0 7.1 21502.4 239.9 9.71 9.71 55.85 31.01 31.01 32.08 0.00 0.00
48.0 6.6 21342.6 239.9 9.18 9.18 54.80 30.93 30.93 31.96 0.00 0.00
Newbasin
Pond, 10 year
Chainsaw Routing Method
Project Name: Davie Middle School
Project # : DGT-96010
Date : 10/3/97
Operator : DAC
Title : Pond, 10 Year Storm
Riser/Barrel
Hydrograph: N =
Op = 41.6 CFS Dr=
Tp = 27.2 minutes Cw =
dT = 1.0 minutes Zcr =
Db =
Stage-Storage : Cd =
Ks = 10209.0 Bar. Invert
=
b = 1.12 Bar. Length =
Zo = 238.0 feet Bar. "n" =
Bar. TW Elev=
Initial Water Level
Zi = 238.0 feet Culvert
N=
Computed Results : D =
Normal Surf. Area = 0.000 acres Cd =
Max. Surf. Area = 0.292 acres Invert
=
Peak Elev. = 240.59 feet Length =
Peak Stage = 2.6 feet Ke =
Peak Outflow = 34.57 CFS n =
Volume Stored = 29486.6 ft3 Culy. TWEL =
Weir 1:
L=
Zcr =
Cw =
The John R. McAdams Company
P.O. Box 14005
Research Triangle Park, NC 27709
System Loading and Response
1.00 45 0
60.00 inches 400
3.00
239.80 feet 35.0
27.00 inches 30.0
0.60
236.20 feet - 25.0
40.00 feet
0
013 3 20.0
. 0
238.00 feet 15.0
100
0.00
0.00 inches 50
0.00 00
Inflow
- - Outflow.
iI
0.00 feet 0.0
0.00 feet
0.00 I . _
0.000
0.00 feet
20.00 feet
240.60 feet
0.00
10.0 20.0 30.0 40.0
Time (min)
Weir 2:
L = 0.00 feet
Zcr = 0.00 feet
Cw = 0.00
50.0

Time
min
Inflow
cfa
Storage
ft"3
Stage
ft
Outflow
cfs
Riser(weir)
cfa
Riser(orif.)
cfs Total
Barrel
cfs Barrel
HW Control
cfs Barrel
TW Control
cfs Culvert
HW Ctrl
cfs Culvert
TW Ctrl
cfs
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.1 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.6 8.3 238.0 0.00 0.00 0.00 0.95 15.75 0.95 0.00 0.00
3.0 1.2 41.5 238.0 0.00 0.00 0.00 1.95 15.81 1.95 0.00 0.00
4.0 2.2 115.6 238.0 0.00 0.00 0.00 3.09 15.94 3.09 0.00 0.00
5.0 3.4 248.5 238.0 0.00 0.00 0.00 4.33 16.14 4.33 0.00 0.00
6.0 4.8 448.9 238.1 0.00 0.00 0.00 5.67 16.42 5.67 0.00 0.00
7.0 8.4 736.7 238.1 0.00 0.00 0.00 7.08 16.80 7.08 0.00 0.00
8.0 8.3 1122.9 238.1 0.00 0.00 0.00 8.55 17.27 8.55 0.00 0.00
9.0 10.3 1618.8 238.2 0.00 0.00 0.00 10.07 17.83 10.07 0.00 0.00
10.0 12.4 2234.5 238.3 0.00 0.00 0.00 11.63 18.48 11.63 0.00 0.00
11.0 14.6 2978.4 238.3 0.00 0.00 0.00 13.23 19.21 13.23 0.00 0.00
12.0 17.0 3857.2 238.4 0.00 0.00 0.00 14.85 20.02 14.85 0.00 0.00
13.0 19.4 4875.9 238.5 0.00 0.00 0.00 16.50 20.89 16.50 0.00 0.00
14.0 21.8 6037.5 238.6 0.00 0.00 0.00 18.15 21.82 18.15 0.00 0.00
15.0 24.1 7343.1 238.7 0.00 0.00 0.00 19.82 22.81 19.82 0.00 0.00
16.0 26.5 8792.1 238.9 0.00 0.00 0.00 21.48 23.83 21.48 0.00 0.00
17.0 28.8 10381.6 239.0 0.00 0.00 0.00 23.14 24.89 23.14 0.00 0.00
18.0 30.9 12107.2 239.2 0.00 0.00 0.00 24.79 25.97 24.79 0.00 0.00
19.0 32.9 13962.5 239.3 0.00 0.00 0.00 26.43 27.07 26.43 0.00 0.00
20.0 34.8 15939.3 239.5 0.00 0.00 0.00 28.04 28.17 28.04 0.00 0.00
21.0 36.5 18028.1 239.7 0.77 0.77 23.98 29.28 29.28 29.63 0.00 0.00
22.0 38.0 20171.4 239.8 5.56 5.56 46.36 30.36 30.36 31.16 0.00 0.00
23.0 39.2 22115.5 240.0 11.86 11.86 59.69 31.30 31.30 32.47 0.00 0.00
24.0 40.2 23755.8 240.1 18.23 18.23 68.89 32.07 32.07 33.53 0.00 0.00
25.0 40.9 25073.7 240.2 23.93 23.93 75.43 32.67 32.67 34.35 0.00 0.00
26.0 41.4 26093.6 240.3 28.66 28.66 80.10 33.12 33.12 34.97 0.00 0.00
27.0 41.6 26857.9 240.4 32.38 32.38 83.42 33.45 33.45 35.42 0.00 0.00
28.0 41.5 27411.0 240.4 33.69 35.15 85.74 33.69 33.69 35.75 0.00 0.00
29.0 41.2 27880.1 240.5 33.89 37.55 87.65 33.89 33.89 36.02 0.00 0.00
30.0 40.5 28315.6 240.5 34.08 39.83 89.38 34.08 34.08 36.27 0.00 0.00
31.0 39.6 28702.1 240.5 34.24 41.88 90.90 34.24 34.24 36.49 0.00 0.00
32.0 38.5 29025.3 240.5 34.38 43.62 92.14 34.38 34,38 36.68 0.00 0.00
33.0 37.1 29271.6 240.6 34.48 44.97 93.07 34.48 34.48 36.81 0.00 0.00
34.0 35.5 29429.0 240.6 34.55 45.83 93.67 34.55 34.55 36.90 0.00 0.00
35.0 33.9 29486.6 240.6 34.57 46.15 93.88 34.57 34,57 36.94 0.00 0.00
Newbasin
Pond, 10 year
Time
min Inflow
cfa Storage
ft"3 Stage
ft Outflow
cfs Riser(weir)
cfs Riser(orif.)
cfs Barrel
cfs HW Control
cfa TW Control
cfs HW Ctrl
cfs TW Ctrl
cfs
36.0 32.3 29445.8 240.6 34.55 45.92 93.73 34.55 34.55 36.91 0.00 0.00
37.0 30.8 29311.2 240.6 34.50 45.18 93.22 34.50 34.50 36.84 0.00 0.00
38.0 29.4 29089.4 240.6 34.41 43.97 92.38 34.41 34.41 36.71 0.00 0.00
39.0 28.0 28786.9 240.5 34.28 42.34 91.22 34.28 34.28 36.54 0.00 0.00
40.0 26.7 28409.9 240.5 34.12 40.33 89.76 34.12 34.12 36.32 0.00 0.00
41.0 25.4 27964.0 240.5 33.93 37.99 87.99 33.93 33.93 36.07 0.00 0.00
42.0 24.3 27454.7 240.4 33.71 35.37 85.92 33.71 33.71 35.77 0.00 0.00
43.0 23.1 26887.3 240.4 32.52 32.52 83.54 33.47 33.47 35.44 0.00 0.00
44.0 22.0 26323.4 240.3 29.76 29.76 81.11 33.22 33.22 35.10 0.00 0.00
45.0 21.0 25860.2 240.3 27.56 27.56 79.06 33.02 33.02 34.83 0.00 0.00
46.0 MO 25467.7 240.3 25.73 25.73 77.27 32.84 32.84 34.59 0.00 0.00
47.0 19.1 25126.0 240.2 24.17 24.17 75.67 32.69 32.69 34.38 0.00 0.00
48.0 18.2 24821.8 240.2 22.81 22.81 74.22 32.55 32.55 34.19 0.00 0.00
Newbasin
Pond, 100 year
Chainsaw Routing Method The John R. McAdams Company
Project Name: Davie Middle School P.O. Box 14005
Project # : OGT-96010 Research Triangle Park, NC 27709
Date : 10/3/97
Operator : DAC
Title : Pond, 100 Year Storm
Riser/Barrel : System Loading and Response
Hydrograph: N = 1.00 1 60.0
Op = 57.2 CFS Dr= 60.00 inches
Tp = 32.6 minutes Cw = 3.00 50.0
dT = 1.0 minutes Zcr = 239.60 feet
Db = 27.00 inches

Stage-Storage :
Cd =
0.60 40,0
Ks = 10209.0 Bar. Invert = 236.20 feet
b = 1.12 Bar. Length = 40.00 feet 30.0
Zo = 238.0 feet Bar. "n" = 0.013
Bar. TW Elev= 238.00 feet 20.0
Initial Water Level
Zi = 238.0 feet Culvert
N = 0.00 100
Computed Results : D = 0.00 inches
Normal Surf. Area = 0.000 acres Cd = 0.00 00
Inflow
Outflow
.r
Max. Surf. Area = 0.298 acres Invert = 0.00 feet 0.0 10.0 20.0 30.0 40.0 50.o
Peak Elev. = 241.05 feet Length = 0.00 feet Time (min)
Peak Stage = 3.0 feet Ke = 0.00
Peak Outflow = 54.74 CFS n = 0.000
Volume Stored = 35385.2 ft' Culy. TWEL = 0.00 feet
Weir 1: Weir 2:
L = 20.00 feet L = 0.00 feet
Zcr = 240.60 feet Zcr = 0.00 feet
Cw = 3.00 Cw = 0.00

Time
min
Inflow
Wall
Storage
ft"3
Stage
ft
Outflow
cfs
Riser(welr)
Will)
Riser(orif.)
cfs Total
Bartel
cfs Barrel
HW Control
cfs Barrel
TW Control
cfs Culvert
HW Ctrl
cfa Culvert
TW Ctrl
cfs
0.0 0.0 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
1.0 0.1 0.0 238.0 0.00 0.00 0.00 0.00 15.73 0.00 0.00 0.00
2.0 0.5 8.0 238.0 0.00 0.00 0.00 0.93 15.75 0.93 0.00 0.00
3.0 1.2 39.7 238.0 0.00 0.00 0.00 1.91 15.81 1.91 0.00 0.00
4.0 2.1 110.9 238.0 0.00 0.00 0.00 3.03 15.93 3.03 0.00 0.00
5.0 3.3 236.9 238.0 0.00 0.00 0.00 4.26 16.12 4.26 0.00 0.00
6.0 4.6 432.2 238.1 0.00 0.00 0.00 5.57 16.40 5.57 0.00 0.00
7.0 6.3 711.2 238.1 0.00 0.00 0.00 6.96 16.77 6.96 0.00 0.00
8.0 8.1 1087.0 238.1 0.00 0.00 0.00 8.42 17.22 8.42 0.00 0.00
9.0 10.1 1572.2 238.2 0.00 0.00 0.00 9.94 17.78 9.94 0.00 0.00
10.0 12.3 2178.2 238.3 0.00 0.00 0.00 11.50 18.42 11.50 0.00 0.00
11.0 14.6 2915.2 238.3 0.00 0.00 0.00 13.10 19.15 13.10 0.00 0.00
12.0 17.1 3792.4 238.4 0.00 0.00 0.00 14.74 19.96 14.74 0.00 0.00
13.0 19.7 4817.5 238.5 0.00 0.00 0.00 16.41 20.84 16.41 0.00 0.00
14.0 22.3 5996.9 238.6 0.00 0.00 0.00 18.10 21.79 18.10 0.00 0.00
15.0 25.0 7335.7 238.7 0.00 0.00 0.00 19.81 22.80 19.81 0.00 0.00
16.0 27.8 8837.3 238.9 0.00 0.00 0.00 21.53 23.86 21.53 0.00 0.00
17.0 30.5 10503.7 239.0 0.00 0.00 0.00 23.26 24.97 23.26 0.00 0.00
18.0 33.3 12335.3 239.2 0.00 0.00 0.00 25.00 26.11 25.00 0.00 0.00
19.0 36.0 14331.2 239.4 0.00 0.00 0.00 26.74 27.28 26.74 0.00 0.00
20.0 38.6 16488.7 239.5 0.00 0.00 0.00 28.47 28.47 28.47 0.00 0.00
21.0 41.1 18803.6 239.7 2.17 2.17 33.87 29.68 29.68 30.19 0.00 0.00
22.0 43.5 21140.6 239.9 8.51 8.51 53.44 30.84 30.84 31.82 0.00 0.00
23.0 45.8 23241.8 240.1 16.14 16.14 66.15 31.83 31.83 33.20 0.00 0.00
24.0 47.9 25021.7 240.2 23.70 23.70 75.18 32.64 32.64 34.32 0.00 0.00
25.0 49.9 26475.4 240.3 30.50 30.50 81.78 33.29 33.29 35.20 0.00 0.00
26.0 51.6 27637.4 240.4 33.79 36.30 86.66 33.79 33.79 35.88 0.00 0.00
270 53.1 28706.4 240.5 34.24 41.91 90.91 34.24 34.24 36.49 0.00 0.00
28.0 54.4 29839.9 240.6 34.82 48.11 95.19 34.72 34.72 37.13 0.00 0.00
29.0 55.5 31017.0 2407 37.27 54.82 99.43 35.20 35.20 37.78 0.00 0.00
30.0 56.3 32110.4 240.8 40.66 61.28 103.19 35.64 35.64 38.37 0.00 0.00
31.0 56.9 33048.9 240.9 44.17 66.99 106.30 36.02 36.02 38.87 0.00 0.00
32.0 57.2 33810.3 240.9 47.35 71.74 108.76 36.32 36.32 39.27 0.00 0.00
33.0 57.2 34398.6 241.0 49.99 75.47 110.61 36.54 36.54 39.57 0.00 0.00
34.0 56.9 34830.0 241.0 52.02 78.25 111.95 36.71 36.71 39.80 0.00 0.00
35.0 56.4 35125.4 241.0 53.45 80.18 112.86 36.82 36.82 39.95 0.00 0.00
Newbasin
Pond, 100 year
Time
min Inflow
cfa Storage
ft"3 Stage
ft Outflow
cfs Riser(weir)
cis Riser(orif.)
cfs Barrel
cfs HW Control
cfs TW Control
cfs HW Ctrl
cfa TW Ctrl
cfs
36.0 55.7 35304,7 241.0 54.34 81.33 113.40 36.89 36.89 40.04 0.00 0.00
37.0 543 35385.2 241.0 54.74 81.86 113.65 36.92 36.92 40.08 0.00 0.00
38.0 53.4 35380.9 241.0 54.72 81.83 113.63 36.92 36.92 40.08 0.00 0.00
39.0 51.9 35302.7 241.0 54.33 81.32 113.40 36.89 36.89 40.04 0.00 0.00
40.0 50.2 35158.9 241.0 53.62 80.38 112.96 36.84 36.84 39.96 0.00 0.00
41.0 48.4 34955.9 241.0 52.62 79.06 112.34 36.76 36.76 39.86 0.00 0.00
42.0 46.5 34702.3 241.0 51.41 77.42 111.55 36.66 36.66 39.73 0.00 0.00
43.0 44.7 34408.2 241.0 50.03 75.54 110.64 36.55 36.55 39.58 0.00 0.00
44.0 42.9 34087.6 240.9 48.57 73.49 109.63 36.42 36.42 39.41 0.00 0.00
45.0 41.3 33749.6 240.9 47.09 71.36 108.56 36.29 36.29 39.24 0.00 0.00
46.0 39.6 33400.3 240.9 45.60 69.17 107.44 36.15 36.15 39.06 0.00 0.00
47.0 36.1 330431 240.9 44.15 66.96 106.28 36.01 36.01 38.87 0.00 0.00
48.0 36.6 32680.3 240.8 42.74 64.73 105.09 35.87 35.87 38.68 0.00 0.00
Newbasin
THE JOHN R. McADAMS COMPANY, INC.
1 P.O Box 14005
Research Triangle Park, North Carolina 27709
- -?' [phone] Fax[phone]
PAGE
J R McA JOB NO. ? !T- N? Q DATE -3 BY I, TSr' CHECKED BY
CLIENT PROJECT
SUBJECT
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OF
(Date)
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0,0-2 2 1,2-d I2,2`j 0.0Z n- CA(- ; V =GK-
THE JOHN R. McADAMS COMPANY, INC.
III P.O. Box 14005
-nom Research Triangle Park, North Carolina 27709
[phone] Fax[phone]
PAGE OF
J R McA JOB NO Dr, A DATE 142 BY ?' `? CHECKED BY
(Date)
CLIENT PROJECT
SUBJECT
Ue?r- Qs er, 'I nP (.? ?V,o> 2.c) FP) j Q - M Aces
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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 0 in cfs : 27.95
slope S in x : .65
pipe diameter D in in. : 30
Manning number n : 0.013
- Dissipator . Pipe or 0uit (D P or 0) -
NRCD Land Quality Section
NYDOT Dissipator Design Results
Pipe diameter (ft) 2.50
Outlet velocity (fps) 7.56
Apron length (ft) 15.00
AVG DIAM STONE THICKNESS
(inches) CLASS (inches)
3 A 9
A 6 B 22 r
13 0 or 1 22
23 2 27
- Dissipator ,Pipe or Quit (D P or 0) -
1 I
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Flow depth (ft) = 1.76
Outlet velocity (fps) = 7.559
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_ 8.5
L T-Yt-D
NRCD Land Quality Section
Pipe Design
Entering the following values will provide you with
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pipe, assuming the Mannings roughness number is
constant over the entire length of the pipe.
WT ,;E:T
flow Q in cfs : 39.22 Flow depth (ft) = 2.50
slope S in X : .5 Outlet velocity (fps) = 7.990
pipe diameter D in in. : 30
Manning nLimber n : 0.013
Pipe flow condition. V=Q/Apipe.
Should double check by another method!!
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NRCD Land Quality Section
NYDOT Dissipator Design Results
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Cutlet velocity (fps) 7.99
Apron length (ft) 15.00
AVG DIAM STONE 7HICMESS
(inches) CLASS (inches)
3 A 9
:. 6 B 22 a
13 B or 1 22
23 2 27
- Dissipator , Pipe or Quit (D P or Q) -
USe ?-r GL S K-+P- f AP
ISlL-x I D I P-,-- ZZi1 Vy
State of North Carolina
Department of Environment,
Health and Natural Resources `
Division of Water Quality
NOW
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary ID E H N 1=?L
A. Preston Howard, Jr., P.E., Director
MEMORANDUM
Date: October 15, 1997
To: John Dorney
From: J. Ray Cox, EITM
Environmental Engineer
Subject: Approved Stormwater Management Plan
Davie Middle School
DWQ #970776
Halifax County
Comments: I have performed a technical review of the Stormwater Management Plan for
the subject project (received October 10, 1997) and have found it adequate to
meet the requirements outlined in the BMP manual. One exception is that the
executed Operation and Maintenance Plan (O&M) has not yet been forwarded
to our office. Amos Clark, the Project Engineer, will fax the signed copy to
us as soon as he receives it from the proper school officials. Mr. Clark is well
aware of the requirements for the O&M plan, so it should be complete and
acceptable. Upon receipt of that document, I recommend approval of the
Stormwater Management Plan.
9707765 WA
Environmental Sciences Branch 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% poet consumer paper
State of North Carolina 'T a
Department of Environment,
LTRMAI
Health arl?d Natural Resources
•
Division of?'Water Quality A4 James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
E H N F?
A. Preston Howard, Jr., P.E., Director
FAX
To: Amos Clark From: Ray Cox
Fam [phone] Pages: 2
Phone: [phone] Date: October 8, 1997
Re: Stormwater Plan Checklist
*Comments: -Call if you have any questions [[phone]].
Environmental Sciences Branch 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% poet consumer paper
MEMO
TO: Sri L?c 77(,
DATE: L,30 2 7
SUBJECT: SIB A4(49'
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fjNp?J ?C?IUE* ?fCovu D Aa I?IET? D S I Inl??c
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T Norarolina Department o nviron ent
H lh eat and Natural R?sourc
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swr.wKrgF P?z.,Bcµt
L TIE JOHN R. McADAMS COMPANY, INC.
CONSULTING ENGINEERS
POST OFFICE BOX 14005
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709 pc ?I,Cr,
[phone] FAX [phone] vG/J .? ??G!!
99>
LETTER OF TRANSMITTAL O ?y 6
To: Ms. Jean Manuele ` Date: September 4. 1997
U. S. Army Corps of Engineers
Raleigh Regulator Branch f,?? 15S1
6508 Falls of the Neuse Road, Suite 120
Raleigh, North Carolina 27615
Re:
William R. Davie Middle School
I am sending you the following item(s):
Job No: DGT-96010
COPIES DATE NO. DESCRIPTION
1 Original of Pre-construction Notification Applica
1 Copy of Pre-construction Notification Applicatiox
2 Prints of construction drawings (C202 and C203

These are transmitted as checked below:
As requested
For approval
For review and comment
Remarks:
For your use
Copy to: John Dorney (7 copies w/ 1 set Signed:
of prints)
aam Yriagen
Senior Project Manager
:ion
I
/ r ?/1
DEM ID: 9 7 0 7_ i CORPS ACTION ID:
NATIONWIDE PERMIT REQUESTED (PROVIDE NATIONWIDE PERMIT #):
PRE-CONSTRUCTION NOTIFICATION APPLICATION
FOR NATIONWIDE PERMITS THAT REQUIRE: ?C????FQ
1) NOTIFICATION TO THE CORPS OF ENGINEERS 1999
2) APPLICATION FOR SECTION 401 CERTIFICATION "q4
3) COORDINATION WITH THE NC DIVISION OF COASTAL MANAGEMENT
S'
SEND THE ORIGINAL AND (1) COPY OF THIS COMPLETED FORM TO THE APPROPRIATE
FIELD OFFICE OF THE CORPS OF ENGINEERS (SEE AGENCY ADDRESSES SHEET). SEVEN
(7) COPIES SHOULD BE SENT TO THE N.C. DIVISION OF ENVIRONMENTAL MANAGEMENT
(SEE AGENCY ADDRESSES SHEET). PLEASE PRINT.
1. OWNERS NAME: Halifax County Board of Education
2. MAILING ADDRESS: Post Office Box 468
CITY: Halifax STATE: North Carolina
SUBDIVISION NAME: N/A
ZIP CODE: 27839
PROJECT LOCATION ADDRESS, INCLUDING SUBDIVISION NAME (IF DIFFERENT FROM
MAILING ADDRESS ABOVE) : William R. David Middle School at the intersection of
US 158 and SR 1428
3. TELEPHONE NUMBER (HOME):
(WORK) : [phone]
4. IF APPLICABLE: AGENT'S NAME OR RESPONSIBLE CORPORATE OFFICIAL, ADDRESS,
PHONE NUMBER:
Mr. Willie Gilchrist, Superintendent of Halifax County Schools
Post Office Box 468, Halifax North Carolina 27839
5. LOCATION OF WORK (PROVIDE A MAP, PREFERABLY A COPY OF USGS TOPOGRAPHIC
MAP OR AERIAL PHOTOGRAPHY WITH SCALE):
COUNTY: Halifax NEAREST TOWN OR CITY: Roanoke Rapids
1

SPECIFIC LOCATION (INCLUDE ROAD
NUMBERS, LANDMARKS, ETC.) : Site of existing William R. David Middle School at
intersection of US 158 and SR 1428 west of Raonoke Rapids on US 158. Old
school to be demolished and new school to be built on the same site.
6. IMPACTED OR NEAREST STREAM/RIVER: None.
RIVER BASIN:
7a. IS PROJECT LOCATED NEAR WATER CLASSIFIED AS TROUT, TIDAL SALTWATER
(SA), HIGH QUALITY WATERS (HQW), OUTSTANDING RESOURCE WATERS (ORW), WATER
SUPPLY (WS-I OR WS-II)? YES [ ] NO [X] IF YES, EXPLAIN:
7b. IS THE PROJECT LOCATED WITHIN A NORTH CAROLINA DIVISION OF COASTAL
MANAGEMENT AREA OF ENVIRONMENTAL CONCERN (AEC)? YES [ ] NO [X]
7c. IF THE PROJECT IS LOCATED WITHIN A COASTAL COUNTY (SEE PAGE 7 FOR
LIST OF COASTAL COUNTIES), WHAT IS THE LAND USE PLAN (LUP) DESIGNATION?
8a. HAVE ANY SECTION 404 PERMITS BEEN PREVIOUSLY REQUESTED FOR USE ON
THIS PROPERTY? YES [ ] NO [X] IF YES, PROVIDE ACTION I.D. NUMBER OF
PREVIOUS PERMIT AND ANY ADDITIONAL INFORMATION (INCLUDE PHOTOCOPY OF 401
CERTIFICATION):
New school to replace old one.
9a. ESTIMATED TOTAL NUMBER OF ACRES IN TRACT OF LAND: 26.80
9b. ESTIMATED TOTAL NUMBER OF ACRES OF WETLANDS LOCATED ON PROJECT SITE:
1.752 Acres
8b. ARE ADDITIONAL PERMIT REQUESTS EXPECTED FOR THIS PROPERTY IN THE
FUTURE? YES [)Q NO [ ] IF YES, DESCRIBE ANTICIPATED WORK:
2
10a. NUMBER OF ACRES OF WETLANDS IMPACTED BY THE PROPOSED PROJECT BY:
FILLING: 0.36 EXCAVATION: -0-
FLOODING: None
OTHER:
None
DRAINAGE: None
TOTAL ACRES TO BE IMPACTED: 0.36
10b. (1) STREAM CHANNEL TO BE IMPACTED BY THE PROPOSED PROJECT (IF
RELOCATED, PROVIDE DISTANCE BOTH BEFORE AND AFTER RELOCATION):
LENGTH BEFORE: None FT AFTER: FT
WIDTH BEFORE (based on normal high water contours) : FT
WIDTH AFTER:
AVERAGE DEPTH BEFORE: FT AFTER: FT
(2) STREAM CHANNEL IMPACTS WILL RESULT FROM: (CHECK ALL THAT APPLY)
OPEN CHANNEL RELOCATION: PLACEMENT OF PIPE IN CHANNEL:
CHANNEL EXCAVATION: CONSTRUCTION OF A DAM/FLOODING:
OTHER:
11. IF CONSTRUCTION OF A POND IS PROPOSED, WHAT IS THE SIZE OF THE
WATERSHED DRAINING TO THE POND? N/A
WHAT IS THE EXPECTED POND SURFACE AREA?
12. DESCRIPTION OF PROPOSED WORK INCLUDING DISCUSSION OF TYPE OF
MECHANICAL EQUIPMENT TO BE USED (ATTACH PLANS: 8 1/2" X 11" DRAWINGS
ONLY) : Grading of site for new school. Conventional grading equipment will
be used.
13. PURPOSE OF PROPOSED WORK: To provide a site for a new middle school for
the Halifax County Public School System.
3

14. STATE REASONS WHY IT IS BELIEVED THAT THIS ACTIVITY MUST BE CARRIED
OUT IN WETLANDS. (INCLUDE ANY MEASURES TAKEN TO MINIMIZE WETLAND
IMPACTS) : The site is somewhat small for the size of the school planner to be
built necessitating the filling of a small amount of wetlands in order to have
enough area for the school to be sited.
15. YOU ARE REQUIRED TO CONTACT THE U.S. FISH AND WILDLIFE SERVICE
(USFWS) AND/OR NATIONAL MARINE FISHERIES SERVICE (NMFS) (SEE AGENCY
ADDRESSES SHEET) REGARDING THE PRESENCE OF ANY FEDERALLY LISTED OR
PROPOSED FOR LISTING ENDANGERED OR THREATENED SPECIES OR CRITICAL HABITAT
IN THE PERMIT AREA THAT MAY BE-AFFECTED BY THE PROPOSED PROJECT. DATE
CONTACTED: N/A (ATTACH RESPONSES
FROM THESE AGENCIES.)
16. YOU ARE REQUIRED TO CONTACT THE STATE HISTORIC-PRESERVATION... OFFICER
(SHPO) (SEE AGENCY ADDRESSES.SHEET) REGARDING THE PRESENCE OF HISTORIC
PROPERTIES IN THE PERMIT AREA WHICH MAY BE AFFECTED BY THE PROPOSED
PROJECT. DATE CONTACTED: N/A
17. DOES THE PROJECT INVOLVE AN EXPENDITURE OF PUBLIC FUNDS OR THE USE OF
PUBLIC (STATE) LAND?
YES [4 NO [I (IF NO, GO TO 18)
a. IF YES, DOES THE PROJECT REQUIRE PREPARATION OF AN ENVIRONMENTAL
DOCUMENT PURSUANT TO THE REQUIREMENTS OF THE NORTH CAROLINA ENVIRONMENTAL
POLICY ACT?
YES [I NO K]
b. IF YES, HAS THE DOCUMENT BEEN REVIEWED THROUGH THE NORTH CAROLINA
DEPARTMENT OF ADMINISTRATION STATE CLEARINGHOUSE?
YES [] NO []
IF ANSWER TO 17b IS YES, THEN SUBMIT APPROPRIATE DOCUMENTATION FROM THE
STATE CLEARINGHOUSE TO DIVISION OF,ENVIRONMENTAL MANAGEMENT REGARDING
COMPLIANCE WITH THE NORTH CAROLINA ENVIRONMENTAL POLICY ACT.
QUESTIONS REGARDING THE.STATE CLEARINGHOUSE REVIEW PROCESS SHOULD BE
DIRECTED TO MS. CHRYS BAGGETT, DIRECTOR STATE CLEARINGHOUSE, NORTH
CAROLINA DEPARTMENT OF ADMINISTRATION, 116 WEST JONES STREET, RALEIGH,
NORTH CAROLINA 27603-8003, TELEPHONE [phone].
4
18. THE FOLLOWING ITEMS SHOULD BE INCLUDED WITH THIS APPLICATION IF
PROPOSED ACTIVITY INVOLVES THE DI-SCHARGE OF EXCAVATED UK FILL MATERIAL
INTO WETLANDS:
a. WETLAND DELINEATION MAP SHOWING ALL WETLANDS, STREAMS, LAKES
AND PONDS ON THE PROPERTY (FOR NATIONWIDE PERMIT NUMBERS 14, 18, 21, 26,
29, AND 38). ALL STREAMS (INTERMITTENT AND PERMANENT) ON THE PROPERTY
MUST BE SHOWN ON THE MAP. MAP SCALES SHOULD BE 1 INCH EQUALS 50 FEET OR 1
INCH EQUALS 100 FEET OR THEIR EQUIVALENT.
b. IF AVAILABLE, REPRESENTATIVE PHOTOGRAPH OF WETLANDS TO BE
IMPACTED BY PROJECT.
C. IF DELINEATION WAS PERFORMED BY A CONSULTANT, INCLUDE ALL DATA
SHEETS RELEVANT TO THE PLACEMENT OF THE DELINEATION LINE.
d. ATTACH A COPY OF THE STORMWATER MANAGEMENT PLAN IF REQUIRED.
e. WHAT IS LAND USE OF SURROUNDING PROPERTY? rural and residential
f. IF APPLICABLE, WHAT IS PROPOSED METHOD OF SEWAGE DISPOSAL?
Sewage from the school site is pumped to the collec tion system of the

Roanoke Rapids Sewer District in Roanoke Ra pids, North Carolina.
g. SIGNED AND DATED AGENT AUTHORIZATION LETTER, IF APPLICABLE.
NOTE: WETLANDS OR WATERS OF THE U.S. MAY NOT BE IMPACTED PRIOR TO:
1) ISSUANCE OF A SECTION 404 CORPS OF ENGINEERS PERMIT,
2) EITHER THE ISSUANCE OR WAIVER OF A 401 DIVISION OF
ENVIRONMENTAL MANAGEMENT (WATER QUALITY) CERTIFICATION, AND
3) (IN THE TWENTY COASTAL COUNTIES ONLY), A LETTER FROM THE
NORTH CAROLINA DIVISION OF COASTAL MANAGEMENT STATING THE,PROPOSED
ACTIVITY IS CONSISTENT WITH THE NORTH CAROLINA COASTAL MANAGEMENT
PROGRAM.
r?
OWNER'S/AGENT'S SIGNATURE
DATE
(AGENT'S SIGNATURE VALID ONLY
IF AUTHORIZATION LETTER FROM
THE OWNER IS PROVIDED (18g.))
5
`--.Halifax County
' ROANOKE /RAP/AS LAKE 44
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PRE-DISCHARGE NOTIFICATION PCN
TO: National Marine Fisheries Service
Pivers Island, NC FAX [phone]
US Fish & Wildlife Service
Asheville, NC FAX [phone]
US Fish & Wildlife Service
Raleigh, NC FAX [phone]
State Historic Preservation Office
Raleigh, NC FAX [phone]
NC Division of Water Quality
Raleigh, NC FAX [phone]
NC Wildlife Resources Commission
Creedmoor, NC FAX [phone]
1. ACTION ID: 199700402
2. APPLICANT: Halifax County Board of Education
3. DATE OF TRANSMITTAL: 9/15/97

1 1997
EWpl,,n nAF r ..1.61_SCIENCES
4. RESPONSE DEADLINE(5 days from transmittal): 9/19/97
5. COMMENT DEADLINE(10 days from response deadline):9/29/97
6. SEND COMMENTS TO: RALEIGH REGULATORY FIELD OFFICE
RALEIGH, NC
ATTN: Jean Manuele
FAX [phone]
We are also forwarding the attached PCN to the Fish and Wildlife
Service and the National Marine Fisheries Service for review and
comment concerning any likely affect to any threatened or
endangered species or their critical habitat within those
agencies' jurisdiction.
State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
October 20, 1997
Mr. Halifax County Board of Education
Post Office Box 468
Halifax, North Carolina 27839
Dear Sirs:
RE: Stormwater pond design approval
W.R. Davie Middle School
Halifax County
DWO # 970776
ID EHNR
DWQ staff have reviewed the revised stormwater management plans sent by your
consultant Sam Pridgen of the John McAdams Company dated 10 October 1997. These plans
will satisfy the additional condition of the 401 Water Duality Certification issued on 18 September
1997. All other conditions of the Certification are still applicable. The final, signed Operation and
Maintenance Plan shall be sent to DWO by 1 November 1997.
Please me at 919-733-1786 if you have any questions.
S' pDorney
970776.fpnd
Cc: Washington DWQ Regional Office
Central Files
Sam Pridgen, John McAdams Company
Ray Cox
Environmental Sciences Branch 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post oonsumer paper
State of North Carolina
Department of Environment,
Health and Natural Resources • •
AA4
Division of Water duality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
H N
A. Preston Howard, Jr., P.E., Director C) E F=?L
September 18, 1997
Halifax County
DWQ Project # 970776
APPROVAL of 401 Water Quality Certification and ADDITIONAL CONDITIONS
Halifax County Board of Education
Post Office Box 468
Halifax, North Carolina 27839
Dear Sir.
You have our approval, in accordance with the attached conditions and those listed below, to fill in 0.36 acres
of wetlands or waters for the purpose of constructing W.R. Davie Middle School at Roanoke Rapids, as you
described in your application dated September 4, 1997. After reviewing your application, we have decided that this
fill is covered by General Water Quality Certification Number 3108 This certification allows you to use Nationwide
Permit Number 26 when it is issued by the Corps of Engineers. In addition, you should get any other federal, state
or local permits before you go ahead with your project including (but not limited to) Sediment and Erosion Control,
Coastal Stormwater, Non-Discharge and Water Supply Watershed regulations. This approval will expire when the
accompanying 404 or CAMA permit expires unless otherwise specified in the General Certification.
This approval is only valid for the purpose and design that you described in your application except as modified
below. If you change your project, you must notify us and you may be required to send us a new application. If total wetland
fills for this project (now or in the future) exceed one acre, compensatory mitigation may be required as described in 15A
NCAC 2H .0506 (h) (6) and (7). For this approval to be valid, you must follow the conditions listed in the attached
certification and any additional conditions listed below.
1. An additional condition is that a final, written stormwater plan including a wet detention basin must be approved
by DWQ before wetland (or stream) impacts occur. Stormwater shall be directed into the remaining wetlands with
non-erosive velocities. (cc: Ray Cox)
If you do not accept any of the conditions of this certification, you may ask for an adjudicatory hearing. You must act
within 60 days of the date that you receive this letter. To ask for a hearing, send a written petition which conforms to
Chapter 150B of the North Carolina General Statutes to the Office of Administrative Hearings, P.O. Box 27447, Raleigh,
N.C. 27611-7447. This certification and its conditions are final and binding unless you ask for a hearing.
This letter completes the review of the Division of Water Quality under Section 401 of the Clean Water Act If you
have any questions, please telephone John Domey at 919-733-1786.
Attachment
cc: Wilmington District Corps of Engineers
Corps of Engineers Raleigh Field Office
Raleigh DWQ Regional Office
Mr. John Dorney
Central Files
Mr. Sam Pridgen, McAdams Co.
9707761tr
Division of Water (duality • Environmental Sciences Branch
Environmental Sciences Branch, 4401 Reedy Creek Rd., Raleigh, NC 27607 Telephone [phone] FAX #t 733-9959
An Equal Opportunity Affirmative Action Employer • 50% recycled110% post consumer paper
l THE JOHN R. McADAMS COMPANY
INC.
CONSULTING ENGINEERS
POST OFFICE BOX 14005
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709
[phone] FAX [phone]
October 10, 1997
RECLwED
Mr. Ray Cox
North Carolina Department of
Environment, Health & Natural Resources
Division of Water Quality
4401 Reedy Creek Road
Raleigh, North Carolina 27607
Re: William R. Davie Middle School
Roanoke Rapids, North Carolina
DWQ #970776
DGT-96010
Dear Mr. Cox:
i "T 1 0 1997.
ENUIRnNAFNTAL.SCENCES
This is in response to your letter of September 18, 1997 to the Halifax County
Board of Education regarding the Additional Conditions of the 401 Water Quality
Certification.
Enclosed are 2 sets of prints showing the water quality pond on the engineering
drawings, 2 copies of our Storm Water BMP Calculation Booklet and narrative,
and one DWQ - 401 Wet Detention Basin Worksheet for your review and
approval. The Maintenance Agreement is being executed by the School Board and
will be sent to you in the next few days.
Your earliest review will be greatly appreciated. Please contact us should you
have any questions.
Sincerely,
THE J N R. McADAMS COMPANY, INC.
eA?
Sam Pridgen
Senior Project Manager
SP:jsh
Enclosure
cc: Mr. Mike Brooks, Doggett Architects
Mr. J. Willie Gilchrist, HCPSS
Project No. DWQ 7 0 2& (to be provided by DWQ)
DIVISION OF WATER QUALITY - 401 WET DETENTION BASIN WORKSHEET
DWQ Stormwater Managcment Plan Review:
A complete stormwater management plan submittal includes a wet detention basin worksheet for each
basin, design calculations, plans and specifications showing all basin and outlet structure details, and a
fully executed operation and maintenance agreement. An incomplete submittal package will result in a
request for additional information and will substantially delay final review and approval of the project.
1. PROJECT INFORMATION (please complete the following information):
Project Name : t?kvI1: PSI iprL-e Se-
Contact Person: V, t ? G -AZ*-- Phone Number: t?
For projects with multiple basins, specify which bas in this worksheet applies to: fJ
Basin Bottom Elevation 23? , L-,) ft. (average elevation of the floor of the basin)
Permanent Pool Elevation 23'a, 0 ft. (elevation of the orifice invert out)
Temporary Pool Elevation. 2V, (y ft. (elevation of the outlet structure invert in)
Permanent Pool Surface Area ?1026) sq. ft. (water surface area at permanent pool. elevation)
Drainage Area ? , 41 ac. (on-site and off-site drainage to the basin)
Impervious Area G, r:;, 3 ac. (on-sire and off-site drainage to the basin)
Permanent Pool Volume 230100 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 1171,52- cu. ft. (volume detained on top of the permanent pool)
Forebay Volume 40eq cu. ft.
SA/DA used (surface area to drainage area ratio)
Diameter of Orifice C - IS in. (draw down orifice diameter)
II. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices
manual (N,C. Department of Environment, Health and Natural- Resources, November 1995) and
Administrative Code Section: 15 A NCAC 2H .1008. Initial in the space provided to indicate the
following design requirements have been. met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why.
Applicants initials
The temporary pool controTs runoff from the 1 inch storm event.
S 1)t7AGH6p5?+r The basin length to width ratio is greater than 3:1.
?I4F The basin side slopes are no steeper than 3: Z.
A submerged and vegetated perimeter shelf at less than 6:1 is provided.
Arr.. ??wr Vegetation to the permanent pool elevation is specified.
G An emergency drain is provided to drain the basin.
'PAC-- The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
>(A ' The temporary pool draws down in 2 to 5 days.
VACC The forebay volume is approximately equal. to 20% of the total basin volume.
DA6, Sediment storage is provided in the permanent pool.
Access is provided for maintenance.
A minimum 30-foot vegetative filter is provided at the outlet.
A site specific operation and maintenance (OWv1) plan is provided.
DAB A vegetation managemenUmowing schedule is provided in the O&M plan.
7?L Semi-annual inspections are specified in the O&M plan.
A debris check is specified in the O&Nf plan to. be performed after every storm. event.
*DAL A specific sediment clean-out benchmark is listed (elevation or depth) in O&M plan.
r?Ci A responsible party is designated in the O&M plan.
FORM SWG100 09/97 Page 1 of t
1
REQUIRED ITEMS CHECKLIST ATTACHMENT
• The basin length to width ratio as designed is approximately 2.2: I, based on an average basin
width at normal pool of 66 feet and length at normal pool of 144 feet. Due to the existing
OV-
site layout constraints, we would be required to encroach on wetland areas to increase this
length to width ratio to 3:1.
• Vegetation on the pond to the permanent pool elevation will be grass. This is not specified
on the plans, but the entire area around and including the pond will be grassed during site
stabilization after the grading operations have ceased.
• A vegetated filter is not provided at the outlet of the pond, nor is it mentioned as a
requirement of a water quality pond in the November 1995 publication of "Stormwater Best
Management Practices" by NCDEHNR. However, the outflow from the pond will run into
existing wetland areas after being spread by a correctly designed energy dissipator (designed
to spread flow for release in non-channelized areas). These wetland areas should serve the
same purpose as a 30' vegetated filter (the wetland areas are greater than 30' long).
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