SW8160410_Historical File_20160524

Cat$mer, Jo
From:
Casmer, Jo
Sent:
Thursday, May 26, 201611:34 AM
To:
'Robert Balland'; tclinkscales
Cc:
Lewis, Linda [e-mail])
Subject:
RE: Surf City K-8 School SW8160410 and Ridge Care SW8160503
Attachments:
Ridge Care.pdf; Surf City K-8 Schools.pdf
That explains why, after several attempts to fax the permit, it failed to go through. It is attached, along with the issued
permit for Ridge Care, for Tim.
From: Robert Balland [maiito:[e-mail]]
Sent: Thursday, May 26, 201610:26 AM
To: Lewis,Unda <[e-mail]>
Cc: Casmer, Jo <[e-mail]>
Subject: RE: Surf City K-8 School SW8160410
Thank you.
Jo, if you could email me a PDF that would be great.
Thanks,
Rob
From: Lewis,Unda [mailto:[e-mail]
Sent: Thursday, May 26, 201610:25 AM
To: Robert Balland <[e-mail]>
Cc: Casmer, Jo <[e-mail]>
Subject: RE: Surf City K-8 School SW8160410
Thanks for the update. I'll make sure Jo knows about your change of mailing address. I think the
permit has already been mailed out, but I'll see if Jo has an opportunity to fax over the permit today.
Linda
From: Robert Balland [mailto:[e-mail]
Sent: Wednesday, May 25, 2016 7:10 PM
To: Lewis,Linda <[e-mail]>; Dan Fisk <[e-mail]>
Cc: Scott, Georgette <[e-mail]>
Subject: RE: Surf City K-8 School SW8160410
Linda,
Good evening. We moved our office this past weekend and I don't believe our fax line is connected at this time. If you
wouldn't mind forwarding us a PDF copy of the permit once its complete, I would greatly appreciate it. Please note our
new address change below.
Thank you,

Robert P. Balland, P.E., LEED AP
PARAMOUNTE ENGINEERING, INC.
122 Cinema Drive
Wilmington, NC 28403
910-791-6707 (P)
910-791-6760 (F)
910-619-1186 (M)
[e-mail]
www.r)aramounte-eng.com
****Please note our new mailing address****
From: Lewis,Linda Imailto:[e-mail]]
Sent: Monday, May 23, 2016 5:49 PM
To: Dan Fisk <[e-mail]>; Robert Balland <[e-mail]>
Cc: Scott, Georgette <[e-mail]>
Subject: Surf City K-8 School SW8160410
Dan and Rob:
Thank you for making those changes to the orifice. If everything checks out, I will be writing up the
permit this afternoon / tomorrow morning.
While I appreciate you changing the design to accommodate the express timelines, I would still like to
sit down at some point in the future and discuss and more fully understand why we are so far apart on
the drawdown times by routing. The only thing I see different is that the time increment used in the
HydroCAD pond drawdown routing calculations sealed on May 11, 2016, is 2.5 hours, and not .0005
hours as indicated in your May 16, 2016 response. I don't have your routing calculations using a time
increment of .0005 hours, which equates to 1.8 seconds. That seems to be a very small time
increment for this situation. I think a time increment of 5-10 minutes (which equates to 0.083 -0.167
hours) would be suitable. Also, the drawdown should start at the actual temporary pool elevation
specified on the supplement form, not the theoretical elevation where the minimum volume
requirement is met. If these two elevations are far apart, it will affect the drawdown time.
Also, the rules require ONLY the design storm volume to be discharged within 2-5 days, not the entire
volume stored between PPE and TPE. The drawdown calculation is started at the provided temporary
pool elevation (as reported on the supplement), since that is the elevation where the next outlet
above the orifice is available. If you start at the theoretical TPE, the driving head will be lower
because the theoretical storage elevation is lower than the provided storage elevation. For most
ponds, the consultant sets the provided TPE at the theoretical TPE, or at least rounds the theoretical
elevation up to the nearest tenth of a foot and reports that as the provided TPE. But where the
consultant sets the provided TPE significantly above the theoretical, the consultant needs to
remember to account for the larger driving head and faster orifice flowrate, to keep the drawdown of
the design storm volume between 2 and 5 days. I've attached a very rudimentary drawing and simple
calculations that depict the situation. Remember, the drawdown is a static calculation, similar to
pulling the plug in a full bath tub (with no inflow) and controlling the time it takes to empty the tub
based on controlling the size of the drain.

We also Sneed to discuss the 90% confidence range for the NOAA precipitation frequency tables.
am curious to know where your information about the use of those ranges comes from.
Thanks.
Linda Lewis, E.I.
Environmental Engineer III
Division of Energy, Mineral and Land Resources
Department of Environmental Quality
910-796-7215 Office
Iinda.lewisAncdenrmov
Wilmington Regional Office
127 Cardinal Drive Extension
Wilmington, NC 28403
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.

MEMORY TRANSMISSION REPORT
TIME :05-24-2016 15:52
FAX NO.1
NAME
FILE N0. 861
DATE 05.24 15:50
TO : zt 97916760
DOCUMENT PAGES 8
START TIME 05.24 15:51 l {�
END TIME 05.24 15:52
PAGES SENT : 0
STATUS 0050
***TX FAILURE NOTICE'"
PAT MCCRORY
b t�lid'AaLD R_ VAA• IDBR V.a1�F.T
ti aarvrry
���` TRA CY 17AVIS
i1NNi,eMM �MrA� pv�
Diieafer
May 2-4, 2016
Dr. Terri Cobb, Superintendent
Pander C_-ou-ty Board of Education
925 Pandarlea Hiitlaway
Bvrgaw NC 28 5
SnbJecte State Stormwater Management Permit No. SVVS 160410
Surf City K-S School
IL3igh Demsity Wet Datamtiom ]Pond 11roJeet
Fender Coarnty
Dear 1Dr. Cobb:
Tian W€lmi n Ragtonal Ulfnce received a complete Stormwnter Management Pos nit Application for
Surf City K-$ School on MW 18, 2016. StafF review of the plans and ape=ificatiami has determined that
the pro_ieot, as proposed. will comply with the Stormwater Regulations set £aorta oa T1tle 1 SA A4CAC
2H.1 O6O and Session Law 2008-21 We are frn-wardingg Permit No. S WS 16041 O dated May 24. 2016.
for the construction, operation and maintenanca oftha nMP's and built -upon area associated with the
subject project.
'1"his permit shall be effective fi+om the date of issuance until lyj v 24. 2024_ and shall be subject to the
conditions and limitations as specified therein. Please pay sp ec to the conditions listed in this
permit re the Operation and Malnteiiairee of the BWW(=> recordation of deed restrictions.
oarNfieati-on of the BMP's, procedures fnr changing ownership, transferring the perrnit, and snowing the
permit. Failure to establish an adequate iWatera for operation and maintenance ortha atoirnwater
rraa ov=n,2etit to record deed restricacma. to certify the ]9MP's, to ta-anafnr the permit, or to resew
the. permit, will rasuI£ :n f:utaure compliance problems.
If any parts, requirements, or limitations contained in this permit are uraaoceptsbla, you have the ripht: to
request an a4iudicatory hearing by filing a written patition with the t7fiica of Administrative Hearings
(OAii). The written petltion muse conform to Chapter 15033 of the North Carolinn Oaneral Statutes, and
must be filed with the OAH within thirty (30) days c f receipt of this permit. You should contact the K AH
With all questions regarding the {lingg The Of a i'i,ing fee is raquirad) and/or the details cf tha filtn fg process
at 6714 Mail Saawice Canter, Rwleaa'ggh, NC 27699-6714, or via talephone at 919-431-3000, or v€art their
website at www.NCOAH.00m_ i7nless such demands are made this permit shall be f€nal and binding.
If you have airy questions. or need additional information oonearning this matter, please contact Linda
Lewia with the 1on of Palergy, Mineral and Land R.esouroas in tfta Wilmington Regional Ofnoe, at
[phone].
since sly,
$i. Tracy Davi P.H., Director
Division of Hnergy, Mineral and Land i2.s—roes
C3I]6/arl_-StarnawatarlPerniits 6; HI IN2016 05 permit 160410
oo: Dan Fiek, P.S., Paramounte Hngineering
Peiadar Covety Plafaamangg
Wimington Regional solos Starmwarer File
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MEMORY TRANSMISSION REPORT
TIME :05-24-2016 15:51
FAX NO.1
NAME
FILE NO.
860
DATE
05.24 15:49
TO
919102590133
DOCUMENT PAGES
8
START TIME
05.24 15:49
END TIME
05.24 15:51
PAGES SENT
8
STATUS
OK
`SUCCESSFUL TX NOTICE""'
Am_
Aor"o, ernaraitresas
■wv,wewMwNT�� dl+q��4T
May Z4, 2016
1)r. Terrt Cobb, Suparitnendant
Pander County Board of Education
925 penderlea highway
Bwtgaw, WC 28425
PAT MCC1 CM-e
Odva.,wr
nn�'4Y.. k7 7R_ V'AN YJ BYt 'VAART
SubJacta State Stornawater Managemnant Pe�olt 1-To. SWS 160410
Surf City IGS Scbool
]Math Daaalty Wet i0eteatlon Pond ProJect
Pcndar County
bear Dr. Cobh:
T1iA C'Y' i}AV18
Dl/eCror
The. Wilmington Re. onal Office rooeived a complete Stornawater Management Permit Application for
Surf City K-8 Sohool ass May 18. 2016. Staff neviaw of the plans and apacificationa iaas datarnained that
rho pa-oJoot, a9 sad, will awmpiy with tine Storrnwatar Regulations set forth in TStla 15A NC:ZAC
2*1 1000 and esaaor Law 2008-21 1. We arc forwardin�gg P__ ermit I%Tn. SWS 160410 dated May 24, 2016,
for the construction, operation and main1 a anon Of the BMP•s and built- Pnn area associated with the
subject project.
This permit shall be ef%otiva f*om tiaa date c f issuance tnatil Ma 24.2
and shall be subject to the
conditions and limitations as specified th—in. Please pay space attarataon to the conditions listed in Baia
permit regarding the p��ration and Maintenance of the ByMP(s) reoordation of dead restrictions,
certification of tits Bss,, procnduraa for changing ownership, 4anafaxring the permit, and ronawing the
permit. Failure to astabiiah as adeouate sysDem fnr operation and maintanan�ee of the atormwazar
management sys to record dae� roetriotiona, to certify the BA"•s, to transfer the permit, or to renew
the permit, w111 rpau t in Raturo compliance problems.
if any parts, roquirentents, or limitations conrainod in this permit are unaocapEsble, you have the right to
request an adjudioatory hearing by flung a written petition with the C31Y—' of Administrative 14—inga
The written petition must con to Chapter I S013 of the North Carolina General Statutes, and
must be Mod with the OAI; within thirty (30) d�ay7/aa of receipt of thin permit. 'Y u should contact the OA a
with all questlone regarding the. filing fee (ifs filing fee is requirod) and/or the datails of the filing process
at 6714 Matl Servioo Center Raleip�lt NC 2-7699-6714, or vas telephone at 919-431-3000. or visit their
webeite at www_NCOAH_com_ 7:Jnleas such demands are made this permit shall be final and binding.
If you have any qqueationa, or nand additioanal information oounoarning this matter, please Contact Linda
Lewis with the 1?ivla#Oar o£Eneray. Mineral and Land Reaourcaa in the Wilmington .Regional Office, at
[phone].
6inc sly,
.�..-rracy I?avi ., I7iractar
Division o£Energy, Mineral and Land Resouroea
43D8/arl: \\\Stormwat='%Pe n lts &a Projects\2016\160410 HI7\2016 05 permit 160410
cc; 17an Risk, P.B., Paranaounte Bngineering
Ponder Counttyy Planaing
'WiiQainl{tan EEtgicraal 6fYlca Smrmwater Pilr
9Nt.OfN'o.e. 4luo4M I Yim/heo,n� Q-W1fW I s�n�6r. M1enn♦L nod Iwed Paawena
xT CW,0101,r amempn 1 VWd+.b.rtwe. aiC xt�os
920 196- 7 1 4teaao7ad.

PARAMOUNTE
E N G 1 N E E FZ I N G, I N C.
5 9 1 1 OLEANDER DRIVE, SUITE 2 0 1
W I L M I N G T O N, NC 2 8 4 0 3
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L E T T F. R () F T R A T%T C M T T 'r e T
To:
NCDENR
Date
105.18.16
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re:
Surf City K-8 School (SW8 160410)
She ards Road
Attn:
Linda Lewis, El
Project No.
I 15348YE
e are sendin ® Originals
he following items: ❑ Correspondence
® Prints ❑ Shop Drawings ® Calculations
® Plans ❑ Specifications ❑ Other as listed below
Quantity
Date
Dwg. No.
Description
2
05.17.16
30"x 42" Revised Design Documents
2
05.17.16
Revised SWM and EC Narrative Calculations
1
3 Revised Wet Pond Supplements (Originals)
1
2 Level Spreader and Veg Filter Supplements (Originals)
1
05.17.16
Response Letter
ssue Status: 0 For Approval ❑ As Requested ❑ Construction ❑ Bid
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
�Action Taken: ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend& Resubmit
❑ ❑ RECEIVED
❑ Rejected - See Remarks Approved as Submitted Other
emarks: MAY I & 20%
Linda
Revised calculations, plans and supplements for the low flow orifice changes. Please feel free to call or email
with any questions.
Thank you,
Cc: Signed: _r r—e'
Daniel J. Fisk, PE

PARAMOUNTE
E N G 1 M E E F2 I N G, I N C.
May 17, 2016
Linda Lewis, E.I. — Environmental Engineer III
NCDENR — DEQ — Energy, Mineral and Land Resources E C E IVE
127 Cardinal Drive Extension
Wilmington, NC 28405 MAY 18 2016
RE: 15348.PE Curf City K-8 School BY.
Town of Surf City, Ponder County
Stormwater Project No. SW8160410
Dear Ms. Lewis:
On behalf of the Pender County Board of Education, we are submitting a response to your comments
emailed on May 16, 2016. Please find your comments listed below with our response provided in
bold.
02H.1003(g)(7) — Provide technical information showing final numbers, calculations,
assumptions, drawings and procedures associated with the stormwater management
measures including but not limited to: Built -upon area, runoff coefficients, runoff volume, runoff
depth, flow routing, inlet and outlet configuration (if applicable), and other applicable
information as specified.
a. The orifice sizing calculations for Ponds 2, 3 and 4 need to be checked. The Division
has checked the numbers using the standard orifice equation (under average head),
the falling head equation assuming a constant area (using the average of the
permanent pool and temporary pool areas), and routing (assuming no inflow). In most
every case, the time to drawdown the pond is much less than 2 days. Drawdown
times (in days) and methods are summarized below:
Pond #1
Pond #2
Pond #3
Pond #4
Proposed Orifice Diameter
5
3
4
6
Design Volume, cf
67,716
20,259
30,064
27,227
Flot;rate, cfs (supplement)
0.35i0.36
0.41
0.47
0.76
Standard Orifice Drawdown dine
2.18
1.54
1.17
0.58
Average H, feet (DEQ)
0.3
0.42
0.5
0.33
Average H, feet (supplement)
0.28/0.3
0.37
0.47
0.3
Avg. flow, cfs (DEQ)
0.36
0.153
0.297
0.546
Falling Head Drawdown time
2.76
2.01
1.36
0.74
Average SA
82,435
18,370
20,211
30,120
Routed Drawdown time
??
1.46
1.25
0.52
Reported TPE (supplement)
35.9
34.25
31.5
35.0
Theoretical TPE consultant
??
34.108
31.408
34.904
s The orifice sizing calculations have been checked and are accurate. The
calculations were routed through the ponds orifice (assuming no inflow)
With a time increment (dt) = 0.0005 hours so that the orifice equation is
recalculated subsequently as the ponds storage elevation changes
accordingly. Having a dt that is too great or infrequent will provide
inaccurate results for a drawdown calculation.
However, due to the time frame in order to get a stormwater permit, the
orifice sizes for Ponds 2, 3 and 4 have been reduced so that the DEQ
5 9 1 1 D L E A N D E R D R I V E, S T E. 20 1, W I L M I N G T O N, No 2 6 4 D 3
F H: (9 1 D) 7 9 1 6 7 0 7 F A X: (9 1 D) 7 9 1 - 6 7 6 D

Average Head equation results in a drawdown time between 2 and 5
days for both the required and provided water quality volume.
b. The routing calculations start at the theoretical TPE which is slightly lower than the
proposed TPE and results in a slightly lower average head. This might explain some
of the difference, but not all. The proposed temporary pool elevation (TPE) should be
used to figure average head and orifice flowrates.
• The opposite is actually true; when routing with a more frequent dt so
that accurate results can be obtained, starting at a higher elevation
which equates to the greater volume (water quality volume provided)
will increase the drawdown time.
From the reference tables provided, it appears you are proposing to
calculate the average head (DEQ) relative to the provided water quality
volume elevation and then using the required volume for the drawdown
calculation. This does not compare apples to apples and is not
accurate. In this scenario it does not make that much of a difference,
but there are other instances where it could be detrimental (for example,
a pond that has a larger volume provided 1.5 times the required, or more
in order to control peak rates for lower frequency storms). The
drawdown time of the required volume should be calculated relative to
the average head for the staging elevation for that volume. The same is
true for the provided volume, as the full provided volume drawdown
time should be calculated by determining an average head of the
provided staging elevation. This is why two (2) average head elevations
and two drawdown times were given for Pond #1.
As noted above, Average Head equation drawdown times are now
provided for all Wet Ponds (1-4) at both the required volume and
corresponding water surface elevation and the provided volume and
corresponding water surface elevation.
c. The orifice flowrates reported on the supplements for Ponds 2, 3 and 4 appear to be
the "peak" flowrates which are much higher than the average flowrates calculated
using the standard orifice equation and average head (1-1/3).
ECEIVE • The supplements have been revised.
MAY 18 2016 There were no Pond Summary HydroCAD calculations or orifice routing calculations
provided for Pond #1.
SY; The Pond #1 orifice sizing / drawdown calculation has always been
performed utilizing the DEQ Average Head equation, therefore,
HydroCAD orifice routing calculations were not provided.
e. The proposed orifice set-up in Ponds 1 & 2 will be difficult for DEQ and school staff to
inspect and maintain. Access to the orifice is necessary to facilitate inspection and
maintenance. It would be better if the orifice in Pond #2 originated in the secondary
outlet structure. Can the outlet structure for Pond #1 be relocated to be closer to the
infiltration basin? The alternative is to provide some type of walk -out bridge or
platform from which the inlet end of the orifice can be attached to (suspend from) for
easy access.
5 9 1 1 O L E A N D E R D R I V E, S T E. 20 1, W I L M I N G T O N, NO 2 S 4 0 3
P H: (9 1 O) 7 9 1 - 6 7 0 7 F A X: (9 1 O) 7 9 1 - 6 7 6 0

• A 2'x2' interior clear box has been added for both Ponds 1 & 2 to help
alleviate inspection and maintenance hardships.
f. Please calculate the overall number of wetlands plants needed for the shelf in each
pond. The BMP Manual suggests 50 plants for each 200 square feet of shelf area. If
the required number of plants is already shown on the plans, please direct me to the
correct sheet number.
• Detail Sheet C-7.3 calls out 'Wet Detention Pond Planting' for each pond.
Within that note it is specified to 'install plants 24" o.c. in a
checkerboard pattern'.
The 24" checkerboard pattern would equate to 50 plants per 200 sf 16'
shelf / 24" = 3 columns] and [200 sf / (6 If x 24 in) =16.67 rows],
therefore, 3x16.67 = 50 per 200 sf.
g. To avoid bypassing and erosion issues, flow from the Pond #4 orifice should enter the
blind swale parallel with the level spreader as was designed for Pond #3 and as
depicted in Figure 8-10 in the BMP Manual.
• The outlet structure and level spreader — vegetated filter strip (LS-VFS)
have been shifted so that the discharge pipe has a greater distance from
the LS-VFS and comes into the blind swale at a less obtrusive angle.
The blind swale has been shown to be extended toward the outlet pipe
and rounded to mitigate erosion. The riprap outlet protection provided
will also provide protection from erosion and is designed to dissipate
the 10-year storm peak rate to a non -erosive velocity.
2. Please keep in mind that changing one number may change other numbers and require the
calculations, supplements, and other supporting documentation to be updated. Verify all
numbers are correct to ensure consistency in the application documents.
Doted, revised calculations, supplements, and plans as a result of the orifice
change for Ponds 2, 3 & 4 are included with the additional information.
Thank you for your attention to this matter.
Sincerely,
Daniel J. Fisk, PE
Paramounte Engineering, Inc.
ECEIVE
MAY 18 2016
BY:
5 9 1 1 O L E A N D E R D R I V E, S T E. 20 1, WILIVII NGTO N, NC S B 4 D 2
P H: (9 1 O) 7 9 1 - 6 7 0 7 F A X: (9 1 O) 7 9 1 - 6 7 6 D

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
STORMWATER MANAGEMENT & EROSION CONTROL
NARRATIVE
Prepared for:
PENDER COUNTY SCHOOLS
925 PENDERLEA HIGHWAY
BURGAW, NC 28425
Prepared by:
PAaA1\4C)'UWTE
I--_N G ! " 6 E 3'2 ! N C3 , ! N C
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
ETC License #: C-2846
Project #15348.PE
April, 2016
Revised May, 2016
'all;
ECEIVE
MAY 18 2016
BY:50

STORMWATER CALCULATIONS
WET PONDS

Surf City K-8 - Wet Pond #2
NC DENR Retention Reauirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area ACRE Value from CAD
Impervious Drainage Area 2.276 ACRE Value from CAD
Impervious Cover 47.12% impervious Cover --(Impervious Drainage
Area)/(Total Drainage Area)*100%
Elevation of Permanent Pool Surface
33.00
FT
Value selected by designer
Depth of Permanent Pool
6.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
27.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation) -(Depth of Permanent P000
Approximate Pond Length
255
FT
Value from CAD
Approximate Pond Width
65
FT
Value from CAD
Len th:Width Ratio
3.9:1
Ratio=(Len th)/ Width :1
Required SA/DA Ratio for 90% TSS Removal 4.07 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 8,562 SF Required Surface Area=(Required SAIDA
Ratio) *(Total Drainage Area)
Provided Permanent Pool Surface Area 16,580 SF Interpolated value from stage -storage calculations
Step 2. Determine the WO runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.474 INIIN Rv=0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 12,466 CF 1.5" Runoff Volume=1.5 inch*Rv*1 fooW 2
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
Volume difference of 1-Year storm)
Volume Below Permanent Pool
Total Volume to be Controlled
20,259 CIF [see HydroCAD calculation]
52,630 CIF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
72 889 CIFTotal Volume to be Controlled=(Volume Below
(Storage Elevation at Required SCS Volume 34.11 FT Value is interpolation based upon stage -storage
values. See stage -storage calculations
Step 3: Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume providea
Total Pond Volume 52,630 CIF Value from stage- storage calculations
Required Total Forebay Volume 9,473 CIF Forebay Volume= otal Pond Volume *18%
Provided Total Forebay Volume 10,588 CIF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 20.1 % (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4A: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
2.50
IN
Value chosen by designer
Elevation of Req'd Volume
34.11
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.11
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.37
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.10
CFS
Q=Cd*(Pi)*((Diameter of Orifice)*(1 ft/12
in)J^214*[2*32.2*(Avenge Head)]41/2
q�
Drawdown Time for Re d WQV
2.35
DAYS
(Drawdown Time)=(Required Runoff Volume)/Q*(1
.a-1PRwnn tee...,. 4.1
Step 4B: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
2.50
IN
Value chosen by designer
Elevation of Outlet Structure
34.25
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.25
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.42
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)1/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.11
CFS
Q=Cd*(Pi)*[(Diameter of Orifice)*(1 ft/12
in)J 2/4 (2 32.2 Ave a Head] 1/2
Drawdown Time for Provided WQV
2.54
DAYS
(Drawdown Time)=(Provided Runoff Volume)/Q*(1
�_..roDenn

Surf City K-8 - Wet Pond #2
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
33.00
16,580
0
0 «•Permanent Pool
34.00
19,420
18,000
18,000
35.00
22,380
20,900
38,900
36.00
25,"0
23,910
62,810
37.00
28,625
27,033
89,843
Stage/Storage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
2,885
0
0 -Sediment Storage
27.0
3,690
0
0 Bottom Elev.
28.0
4,580
4,135
4,135
29.0
6,680
5,630
9,765
30.0
8,435
7,558
17,323
31.0
10,350
9,393
26,715
32.0
12,450
11,400
38,115
33.0
16,580
14,515
52,630 -Permanent Pool
Forebay
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
570--Sediment
Storage
29.0
1,135
0
0 «-Bottom Elev.
30.0
1,835
1,485
1,485
31.0
2,600
2,218
3,703
32.0
3,430
3,015
6,718
33.0
4,310
3,870
10,588 +forebay Volume

Surf City K-8 - Wet Pond #3
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 9.904 ACRE Value from CAD
Impervious Drainage Area 3.512 ACRE Value from CAD
Impervious Cover 35.46% Impervious Cover=(Impervious Drainage
Area)/(Total Drainage Area) 100%
Elevation of Permanent Pool Surface
30.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
(Bottom Elevation)=(Permanent Pool Surface
Elevation of Wet Detention Pond Bottom
25.0
FT
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
255
FT
Value from CAD
Approximate Pond Width
77
FT
Value from CAD
Len th:Width Ratio
3.3:1
Ratio= Len th /(Width):1
Required SAIDA Ratio for 90% TSS Removal 3.55 Value from chart. Reference: "90%u TSS Removal
Required Permanent Pool Surface Area 15,315 SF Required Surface Area=(Required SAIDA
Ratio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 19,660 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.369 IN/IN Rv=0.05+0.009*(116 Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 19,909 CF 1.5" Runoff Volume=1.5 inch*Rv*l foot/12
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
Volume difference of 1-Year storm)
30,064 CF [see HydroCAD calculations]
Volume Below Permanent Pool 62,503 CF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 82,411 CF Total Volume to be Controlled=(Volume Below
Permanent Pool)+(Required Runoff Volume)
Storage Elevation at Required SCS Volume 31 Al FT Value is interpolation based upon stage -storage
values. See stage -storage calculations
Step 3: Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume provided
Total Pond Volume 62,503 CF Value from stage -storage calculations
Required Total Forebay Volume 11,250 CF Forebay Volume= Total Pond Volume *18%
Provided Total Forebay Volume 12,625 CF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 20.2% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4A: Verify that time required to arawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Req'd Volume
31.41
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.41
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.47
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]13-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.16
Q=Cd*(Pi)*((Diameter of Orifice)*(1 fill
in)]^214*(2*32.2*(Averge Head)]^112
Drawdown Time for Req'd WQV Runoff
2.15
DAYS
(Drowdown^Time) (Required Runoff Vo1ume)/Q*(1
Step 4B: Verify that time required to drawdown the provided water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Req'd Structure
31.50
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.50
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.50
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]13-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.17
Q=Cd*(Pi)*((Diameter of Orifice) *(I W12
In)]^214*[2*32.2*(Avenge Head)]^12
Drawdown Time for Provided WQV Runoff
2.23
DAYS
(Drawdown Time)=(Provided Runoff Volume)1Q*(1

Surf City K-8 - Wet Pond #3
Stage -Storage Calculations for Proposed Wet Detention Pond
Stagei,worage Above rermanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
30.00
19,660
0
0 •Permanent Pool
31.00
21,795
20,728
20,728
32.00
24,000
22,898
43,625
33.00
26,260
25,130
68,755
34.00
28,575
27,418
96,173
35.00
30,950
29,763
125,935
35.50
32,160
15,778
141,713
Stage/Storage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
6,180
- -Sediment Storage
25.0
7,585
0
0 Bottom Elev.
26.0
9,185
8,385
8,385
27.0
10,995
10,090
18,475
28.0
13,055
12,025
30,500
29.0
15,645
14,350
44,850
30.0
19,660
17,653
62,503 rPermanent Pool
Forebay #1
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
590
-
- ----Sediment Storage
25.0
960
0
0 ••Bottom Elev.
26.0
1,435
1,198
1,198
27.0
2,030
1,733
2,930
28.0
2,785
2,408
5,338
29.0
3,625
3,205
8,543
30.0
4,540
4,083
12,625 -Forebay Volume

Surf City K-8 - Wet Pond #4
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3:1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 4.516 ACRE Value from CAD
Impervious Drainage Area 2.755 ACRE Value from CAD
Impervious Cover 61.00% Impervious Cover -(Impervious Drainage
Area)/(Total Drainage Area) *100%
Elevation of Permanent Pool Surface
34.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
29.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation) -(Depth of Permanent Pooq
Approximate Pond Length
FT
Value from CAD
Approximate Pond Width
71
FT
Value from CAD
Len th:Width Ratio
5.6:1
Ratio= Len h /(Widih):1
Required SAIDA Ratio for 90% TSS Removal 7.11 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 13,986 SF Required Surface Area=(Required SAIDA
Ratio) -(Total Drainage Area)
Provided Permanent Pool Surface Area 28,320 SF interpolated value from stage -storage calculations
Step 2: Determine the INQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.599 INAN Rv=0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 14,729 CF 1.5" Runoff Vo1ume=1.5 inch*Rv*1 foot/12
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
Volume difference of 1-Year stone)
27,227 CF [see HydroCAD calculations]
Volume Below Permanent Pool 81,905 CF
Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 109,132 CF Total Volume to be Controlled=(Volume Below
Permanent Pool) + Re uired Runoff Volume
Storage Elevation at Required Volume 34.90 FT Value is interpolation based upon stage -storage
values. See stace-storaoe calculations
Step 3. Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume provided
Total Pond Volume 81,905 CF Value from stage -storage calculations
Required Total Forebay Volume 14,743 CF Forebay Volume= otal Pond Volume *18%
Provided Total Forebay Volume 16,113 CF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 19.7% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4A: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Req'd Volume
34.90
FT
Value chosen by designer
Total Elevation Head Above Orifice
0.90
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=[(Storage
Average Elevation Head Above Orifice
0.30
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.13
Q=Cd*(Pi)*[(Diameter of Orifice)*(1 ft/12
*(A
in)] 2/4 [2 32.2 verge Hea d)r 1/2
Drawdown Time for Re d WQV Runoff
2.43
DAYS
(Drawdown Time)=(Required Runoff V61ume)/Q*(1
Step 4B: Verify that time required to drawdown the provided water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Provided Volume
35.00
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.00
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=[(Storage
Average Elevation Head Above Orifice
0.33
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)1/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.14
Q=Cd*(Pi)*[(Diameter of Orifice) *(I ft/12
in)] 2/4 [2 32.2 (Averge Head)] 1/2
Drawdown Time for Provided WQV Runoff
2.55
DAYS
(Drawdown Time) (Provided Runoff Volume)/Q*(1

Surf City K-8 - Wet Pond #4
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
34.00
28,320
0
0 �Pennanent Pool
35.00
31,920
30,120
30,120
36.00
35,575
33,748
63,868
37.00
39,290
37,433
101,300
37.25
40,225
9,939
111,239
Stage/Storage Main Pond (Not Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
5,265
-
- -Sediment Storage
29.0
7,000
0
0 FBottom Elev.
30.0
9,085
8,043
8,043
31.0
11,345
10,215
18,258
32.0
13,775
12,560
30,818
33.0
16,900
15,338
46,155
34.0
22,375
19,638
65,793Permanent Pool
Stage/Storage Total Pond (Including Forebay)
Main Pond
Cumulative
Volume
Forebay
Volume, S
Contour
(CF)
Volume (CF)
(CF)
28.0
-
0
29.0
0
-
0
30.0
8,043
0
8,043
31.0
18,258
2,848
21,105
32.0
30,818
6,410
37,228
33.0
46,155
10,760
56,915
34.0
65,793
16,113
81,905
Forebay #1
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
1,380
-
- --Sediment Storage
29.0
1,905
-
-
30.0
2,510
0
0 Bottom Elev.
31.0
3,185
2,848
2,848
32.0
3,940
3,563
6,410
33.0
4,760
4,350
10,760
34.0
5,945
5,353
16,113 +forebay Volume

STORMWATER CALCULATIONS
LEVEL SPREADERS

Project Name: Surf City K-8_......_....._..................---- .................... _.. ---...._....._.....-
Client: LS3P PA_R.A,MOUNTE
Project Number: 15348.PE
Prepared By: DJF
Date: 5/17/16
Secondary 'Effective Inflltratlon System' Design - LS-VFS #3
Soils Testing Information:
Soil Type = Leon Fine Sand (LnA)
EL. At Test Location = 30.50
Depth to SHWL = 0.83 ft
SHWL = 29.67
"Effective Infiltration Rate" = 0.52 in/hr (Assumed minimum to calculate VFS)
Stormwater Quality Requirement:
lyr Volume (SCS Method) 30,064 cf
Draw Down Analysis:
Area of VFS =
6,000 sf
Length of VFS =
100 ft
Width of VFS =
60 ft
Draw Down Time =
4.82 days (from Darcys Equation)
HydroCAD 10-YR Flow Analysis:
10-YR Q =
8.93 cfs
Req'd LS Length =
89 ft (Per BMP Manual - 10 Ft / 1 cis)
Provided LS Length =
100 ft

15348.PE SWM POST Type 111 24 hr 10-Year Rainfall=6.99"
Prepared by Paramounte Engineering, Inc. Printed 5/17/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 21
Summary for Pond 15P: Wet Pond #3
Inflow Area = 431,418 sf, 35.46% Impervious, Inflow Depth = 4.69" for 10-Year event
Inflow = 55.95 cfs @ 12.07 hrs, Volume= 168,441 cf
Outflow = 8.93 cfs @ 12.55 hrs, Volume= 164,663 cf, Atten= 84%, Lag= 28.5 min
Primary = 8.93 cfs @ 12.55 hrs, Volume= 164,663 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 33.46' @ 12.55 hrs Surf.Area= 27,330 sf Storage= 81,431 cf
Plug -Flow detention time= 396.4 min calculated for 164,663 cf (98% of inflow)
Center -of -Mass det. time= 383.0 min ( 1,190.1 - 807.1 )
Volume Invert Avail.Storage Storage Description
#1 30.00' 141,713 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
30.00 19,660 0 0
31.00 21,795 20,728 20,728
32.00 24,000 22,898 43,625
33.00 26,260 25,130 68,755
34.00 28,575 27,418 96,173
35.00 30,950 29,763 125,935
35.50 32,160 15,778 141,713
Device Routing Invert Outlet Devices
#1 Primary 30.00' 15.0" Round Culvert
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 30.00'/30.00' S= 0.0000 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 30.00' 3.0" Vert. Low Flow Orifice C= 0.600
#3 Device 1 31.50' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 33.75' Emergency Spillway, C= 2.60
Offset (feet) 0.00 4.50 64.50 69.00
Height (feet) 1.50 0.00 0.00 1.50
Primary OutFlow Max=8.93 cfs @ 12.55 hrs HW=33.46' TW=0.00' (Dynamic Tailwater)
L1=Culvert (Barrel Controls 8.93 cfs @ 7.27 fps)
t3=To2=Low Flow Orifice (Passes < 0.43 cfs potential flow)
p
of Box (Passes < 60.70 cfs potential flow)
econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=30.00' TW=0.00' (Dynamic Tailwater)
4=Emergency Spillway ( Controls 0.00 cfs)

15348.PE SWM POST Type lil 24-hr 90-Year Rainfall=6.99"
Prepared by Paramounte Engineering, Inc. Printed 5/17/2016
HydroCAD® 10.00-11 s/n 08877 02014 HydroCAD Software Solutions LLC Page 22
Pond 15P: Wet Pond #3
Hydrograph
60
50
40
30
❑ inflow
Inflow Area=431,418 sf
❑ Outflow
Infltiw=55.95 Ofs-Q-1Z.07 hrs
❑ Primary
Outflow=8.93 qfs @ 12.85 hro
SecondaryEl
PHrnary=6.93 pfs 12.55 hrs
Secondary70.00 cfs @ 0.00 hrs
Peak Elev=33.46'
Storage=84,4cf 31
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

ProjectName: Surf City K-8....................................................................................................................................................
Client: LS3P P,A R A O U .L 7J T E
Project Number: 15348.PE
Prepared By: DJF
Date: 5/17/16
Secondary 'Effective Infiltration System' Design - LS-VFS #4
Soils Testing Information:
Soil Type = Mandarin Fine Sand (Ma) / Murville Muck (Mu)
EL. At Test Location = 34.00
Depth to SHWL = 0.83 ft
SHWL = 33.17
"Effective Infiltration Rate" 0.52 in/hr (Assumed minimum to calculate VFS)
Stormwater Quality Requirement:
iyr Volume (SCS Method) 27,227 cf
Draw Down Analysis:
Area of VFS
5,250 sf
Length of VFS =
70.00 ft
Width of VFS =
75.00 ft
Draw Down Time =
4.99 days (from Darcy's Equation)
HydroCAD 10-YR Flow Analysis:
10-YR Q =
6.49 cfs
Req'd LS Length =
65 ft (Per BMP Manual - 10 Ft / 1 cfs)
Provided LS Length =
70 ft

15348.PE SWM POST Type III24-hr 10-Year RainfaiM.99"
Prepared by Paramounte Engineering, Inc. Printed 5/17/2016
HydroCAD® 10.00-11 s/n 08877 02014 HydroCAD Software Solutions LLC Page 23
Summary for Pond 17P: Wet Pond #4
Inflow Area = 196,630 sf, 61.01% Impervious, Inflow Depth = 5.93" for 10-Year event
Inflow = 30.48 cfs @ 12.07 hrs, Volume= 97,150 cf
Outflow = 6.49 cfs @ 12.47 hrs, Volume= 91,237 cf, Atten= 79%, Lag= 24.1 min
Primary = 6.49 cfs @ 12.47 hrs, Volume= 91,237 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 35.61' @ 12.47 hrs Surf.Area= 34,146 sf Storage= 50,670 cf
Plug -Flow detention time= 606.4 min calculated for 91,237 cf (94% of inflow)
Center -of -Mass det. time= 572.9 min ( 1,348.4 - 775.5 )
Volume Invert Avail.Storage Storage Description
#1 34.00' 111,239 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubicfeet) (cubic -feet)
34.00 28,320 0 0
35.00 31,920 30,120 30,120
36.00 35,575 33,748 63,868
37.00 39,290 37,433 101,300
37.25 40,225 9,939 111,239
Device Routing Invert Outlet Devices
#1 Primary 34.00' 23.0" W x 14.0" H, R=22.0" Elliptical RCP _Elliptical 23x14
L= 40.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 34.00' / 34.00' S= 0.0000 '/' Cc= 0.900
n= 0.013, Flow Area= 1.83 sf
#2 Device 1 34.00' 3.0" Vert. Low Flow Orifice C= 0.600
#3 Device 1 35.00' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 35.95' Emergency Spillway, C= 2.60
Offset (feet) 0.00 3.90 103.90 107.80
Height (feet) 1.30 0.00 0.00 1.30
nmary OutFlow Max=6.49 cl's @ 12.47 hrs HW=35.61' TW=0.00' (Dynamic Tailwater)
P=RCP_Elliptical 23x14 (Barrel Controls 6.49 cfs @ 3.55 fps)
2=Low Flow Orifice (Passes < 0.29 cfs potential flow)
3=Top of Box (Passes < 18.65 cfs potential flow)
econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=34.00' TW=0.00' (Dynamic Tailwater)
Emergency Spillway ( Controls 0.00 cfs)

15348.PE SWM POST Type 111 24 hr 10-Year Rainfall=6.99"
Prepared by Paramounte Engineering, Inc. Printed 5/17/2016
HydroCAD®10.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 24
Pond 17P: Wet Pond #4
Hydrograph
❑ Inflow
Inflow Area=196,630 sf
❑ Outflow
Inflow=30.48 cfs @ 12.07 hrs
❑ Primary
30
Outflow=6.49 cfs @ 12.47 hrs
Primary=6.49 cfs @ 12.47 hrs]
25
Secondary=0.00 cfs_.@_ 0.00 hrs
Peak Elev=35.61'
.-.
Storage=50,670 cf
20
v
o 15
LL
10
0 5 10.15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

Lewis,Linda
From: Lewis,Linda
Sent: Monday, May 16, 2016 5:50 PM
To: Robert Balland; Dan Fisk ([e-mail])
Cc: Scott, Georgette; '[e-mail]'
Subject: SW8 160410 Surf City K-8 School
Attachments: WIRO DEMLR Letterhead Black 12042015.pdf
Attached please find my Express review comments for the subject redesigned project.
Thanks,
Linda

Energy, Mineral
and Land Resources
!ENVIRONMENTAL QUALITY
May 16, 2016
Dr. Terri Cobb, Superintendent
Pender County Board of Education
925 Penderlea Highway
Burgaw, NC 28425
Subject: Request for Additional Information
Stormwater Project No. SW8 160410
Surf City K-8 School
Pender County
Dear Dr. Cobb:
PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary
TRACY DAVIS
Director
The Wilmington Regional Office received and accepted an Express State Stormwater Management Permit
Application for Surf City K-8 School on April 29, 2016. A preliminary in-depth review of that
application was completed on May 4, 2016 and additional information was requested. The design concept
was changed and the new submittal information was received on May 11, 2016 and reviewed on May 13,
2016. The application is not complete and the following information is needed to continue the stormwater
review:
02ii 1003(g)(7) —Provide technical information showingfinal numbers, calculations,
assumptions, drawings and procedures associated with the stormwater management
measures including but not limited to: Built -upon area, runoff coefficients, runo f volume,
runoff depth, flow routing, inlet and outlet configuration (if applicable), and other
applicable information as specified.
a. The orifice sizing calculations for Ponds 2, 3 and 4 need to be checked. The Division
has checked the numbers using the standard orifice equation (under average head),
the falling head equation assuming a constant area (using the average of the
permanent pool and temporary pool areas), and routing (assuming no inflow). In
most every case, the time to drawdown the pond is much less than 2 days. Drawdown
times (in days) and methods are summarized below -
Pond # 1
Pond 42
Pond #3
1 Pond #4
Proposed Orifice Diameter
5
3
4
6
Design Volume cf
67,716
20 259
30 064
27 227
Flowrate cfs _ evvent
0.35 .36
0.41
0.47
Standard Orifice Drawdown time
2.18
1.54
1.17
0.58
Average H feet E
0.3
0.42
0.5
0.33
Average H feet (supplement)
0.28/0.3
0.37
0.47
0.3
Av . flaw, cfs
0.3
0.1 3
0.297
0.546
Falling Head Drawdown time
2.76
2.01
1.36
0.74
Average SA
82,435
18,370
2200,221111
30,120
Routed Drawdown time
??
1.46
1.25
0.52
Reported TPE (supplement)
35.9
34.25
31.5
35.0
Theoretical TPE consultant
??
34.108
31.408
34.904
b. The routing calculations start at the theoretical TPE which. is slightly lower than the
Proposed TPE and results in a slightly lower average head. This might explain some
of the difference, but not all. The proposed temporary pool elevation (TPE) should
be used to figure average head and orifice flowrates.
State of North Carolina I Environmental Quality I Energy, Mineral and Land Resources
127 Cardinal Drive Extension I Wilmington, NC 28405
910 796 7215 T 1 910 350 2004 F I htip://nortal.ncdenr.ore/web/Ir/

State Stormwater Permit No. SW8 160410
Page 2 of 2
c. The orifice flowrates reported on the supplements for Ponds 2, 3 and 4 appear to be
the "peak" flowrates which are much higher than the average flowrates calculated
using the standard orifice equation and average head (11/3).
d. There were no Pond Summary HydroCAD calculations or orifice routing calculations
provided for Pond # 1.
e. The proposed orifice set-up in Ponds I & 2 will be difficult for DEQ and school staff
to inspect and maintain. Access to the orifice is necessary to facilitate inspection and
maintenance. It would be better if the orifice in Pond #2 originated in the secondary
outlet structure. Can the outlet structure for Pond #1 be relocated to be closer to the
infiltration basin? The alternative is to provide some type of walk -out bridge or
platform from which the inlet end of the orifice can be attached to (suspended from)
for easy access.
f. Please calculate the overall number of wetlands plants needed for the shelf in each
pond. The BUT Manual suggests 50 plants for each 200 square feet of shelf area. If
the required number of plants is already shown on the plans, please direct me to the
correct sheet number.
g. To avoid bypassing and erosion issues, flow from the Pond #4 onfice should enter
the blind Swale parallel with the level spreader as was designed for Pond #3 and as
depicted in Figure 8-10 in the BMP Manual.
2. Please keep in mind that changing one number may change other numbers and require the
calculations, supplements, and other supporting documentation to be updated. Verify all
numbers are correct to ensure consistency in the application documents.
Please note that this request for additional information is in response to a preliminary review. The
requested information should be received in this Office prior to May 23, 2016, or the application will be
returned as incomplete. If the permit cannot be issued by May 29, 2016, the project will have to be
returned incomplete. If you wish to re -submit to the Express Program, you will need to resolve the design
discrepancies described above and reschedule the project through the Express Coordinator for the next
available review date. All of the required items must be resubmitted at that time, including the application
fee.
If you would like to meet to go over these review comments, or if you need additional time to submit the
requested information, please email your request to me. A request for additional time must indicate the
date by which you expect to submit the required information, which shall be no later than 5 business days
-past the original due date. I will do my best to schedule a short meeting as quickly as possible for the
orifice calculations, if you feel it's needed.
The construction of any impervious surfaces, other than a construction entrance under an approved
Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject to enforcement
action pursuant to NCGS 143-215.6A.
Please label all packages and cover letters as "Express" and reference the project name and State
assigned project number on all correspondence. If you have any questions concerning this matter, please
feel free to call me at [phone] or email me at [e-mail].
Sincerely,
Linda Lewis, E.I.
Environmental Engineer III
GDS/arl: \\\Stormwater\Permits & Projects\2016\160410 HD\2016 05 addinfo_2 160410
cc: Robert Balland, P.E., Paramounte Engineering (via email attachment)
Wilmington Regional Office Stormwater File
State of North Carolina I Environmental Quality I Energy, Mineral and Land Resources
127 Cardinal Drive Extension I Wilmington, NC 28405
910 796 7215 T 1 910 350 2004 F I htto://Dortal.nedenr.ore/web/k/

PARAMOUNTE
E N G 1 N E E R 1 N G, 1 N C,
5 9 1 1 OLEANDER DRIVE, SUITE 20 1
vW I L M I N G T O N, NC 2 S 4 0 s
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L E T T E R O F T R A N S M I T T A L
To:
NCDENR
Date
05.11.16
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re:
Surf City K-8 School (SW8 160410)
Shepards Road
Attn:
Linda Lewis, El
Pro'ectNo.
15348.PE
e are se n
® Originals
® Prints
❑ Shop Drawings
❑ Calculations
❑ Correspondence
❑ Plans
❑ Specifications
❑ Other as listed below
e followin items:
Description
*&M (Storm EZ) (Original and Copy)
a o
ssue Status: ® For Approval E]As Requested ❑ Constru�yy
tti Bid
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
tion Talcen: ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend & Resubmit
❑ Rejected - See Remarks ❑ Approved as Submitted ❑ Other
ematics:
Cc:
Signed:
Daniel J. Fisk, PE
RECEIVED
MAY 112016

A
PARAMOUNTE
E " G 1 M E E FR 1 N G, 1 N C.
5 9 1 1 OLEANDER DRIVE, SUITE 2 0 1
vVI L M 1 N is T v iV , N C 2 8 4 0 3
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L E T T E R n F T R A N S M I T 'I' A i.
To:
NCDENR
Date
105.11.16
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re:
Surf City K-8 School (SW8 160410)
Shepards Road
Attn:
Linda Lewis, El
Pro'ectNo.
I 15348.PE
e are sendiux
® Originals
® Prints
❑ Shop Drawings
® Calculations
❑ Correspondence
® Plans
❑ Specifications
❑ Other as listed below
he followin items:
Quantity
Date
Dwg. No.
Description
2
05.11.16
30"x 42" Revised Design Documents
[C-2.04, C-3.04, C-3.15, C-3.18, C-6.2-C-6.5 & =-1 did not change]
C-7.8 can be deleted from the set as the pumps have beer. removed
2
05.11.16
SWM and EC Narrative
1
4 Wet Pond Supplements (Originals)
1
2 Infiltration Basin Supplements (Originals)
1
2 Level Spreader and Veg Filter Supplements (Originals)
O&M (Storm EZ) — Being Coordinated with Owner — To be provided
under separate cover
ssue Status: ® For Approval ❑ As Requested ❑ Construction ❑ Bi it 144 y l 12016
BY
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
[Action Taken: ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend & Resubmit
❑ Rejected See Remarks ❑ Approved as Submitted ❑ Other RECEIVED
marks: RECEIVED MAY
Linda
Revised plans, calculations and suppleineiits as discussed. Due to the number of BMPs changing, the O&M EZ is
currently in the owner's hands for signature and will be provided under separate cover (original and copy). Road
names have been added to the typical templates. Line and arc dimensions have been added for the permanent
pool contours. After an agreement with the Fire Departtnent, the grass pavers have been removed.
Cc: Signed: ell"),LD
Daniel J. Fisk, PE

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
STORMWATER MANAGEMENT & EROSION CONTROL
NARRATIVE
Prepared for:
PENDER COUNTY SCHOOLS
925 PENDERLEA HIGHWAY
BURGAW, NC 28425
Prepared by:
........ ..... .__ .-..................... . .... ......... _............
_.. __ .. _....... _ __............_.........._._ _.
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
NC License #: C-2846
Project K15348.PE
ECEIVE April, 2016
MAY i 201s evised May, 2016

SURF CITY K-S SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
Project #15348.PE
Table of Contents
Design Narrative
Proposed Improvements
Design Method
Calculation Summary
Maintenance
Erosion and Sedimentation Control Specification
Soils Map
Reference Data
USGS Map
Erosion Control Calculations
Stormwater Calculations Overall
Stormwater Calculations Wet Ponds
Stormwater Calculations Infiltration Basins
Stormwater Calculations Level Spreader
Soils Report (By Others)
Page

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
Project #15348.PE
DESIGN NARRATIVE
Pender County Schools is proposing to construct a new K-8 School on a 99.22-acre site off of
Shepards Road in the Town of Surf City in Pender County, NC. The latitude and longitude of
the property are 34' 27' 46" N, 77' 34' 28" W. The site is further identified by Pender County
Parcel Identification Number#: 4226-92-2047-0000.
The existing site is relatively flat with wetland areas and wooded ground cover. The existing
site is split into two drainage areas; the southern portion ultimately drains to Becky's Creek and
the northern portion ultimately drains to County Line Branch. Both Becky's Creek and County
Line Branch have a stream classification of SA, HQW. The site discharge points are greater than
575 feet from the HQW. Soils consist mainly of Leon fine sand(LnA) (HSG A/D), Mandarin fine
sand (Ma) (HSG B/D) and Murville muck (Mu) (HSG A/D), according to the NRCS soil survey.
The seasonal high water table for the proposed wet ponds were determined using the
parameters described on pages 10-9 and 10-10 of the BMP manual; therefore, using good
engineering judgement by field survey, inspection, and discussion with client on existing
conditions of the outfall; lead to the setting of each respective outfall elevation. The elevation
for the permanent pool and seasonal high water table was determined as well by observing the
wetlands throughout the area and the surveyed elevation of the wetland areas.
PROPOSED IMPROVEMENTS
The applicant is proposing to build a K-8 School along with associated parking, access roads,
athletic fields, pump station and stormwater management system. Runoff resulting from
impervious surfaces will be collected by a combination of overland flow, swales, and an
underground (piped) storm drainage system. The conveyance system will then be discharged
to one of four (4) wet detention ponds designed for 90% TSS removal.
Due to the site's discharge points being within 1/2 mile of SA waters, each wet pond's water
quality volume will discharge to a secondary BMP. Wet Pond 1 and Wet Pond 2 will discharge
by gravity to Infiltration Basin 1 and Infiltration Basin 2 respectively. Wet Pond 3 and Wet
Pond 4 have been designed to discharge to a Level Spreader - Vegetated Filter Strip (LS-VFS) in
accordance with the 'Options for Complying with the 'No Direct Discharge to SA Waters
Provision of the Coastal Stormwater Rule' published March 7, 2014 Option 3B. The LS-VFS
have been designed above and beyond the requirements of this option as the provided surface

area and length of level spreader have been increased beyond the requirements in the NCDENR
Stormwater BMP Manual to provide an 'effective' infiltration within a 5 day period by utilizing
the equation provided in the BMP manual under Section 16.3.6 and applying the minimum 0.52
in/hr infiltration rate.
The ponds have been designed to meet NCDENR requirements, which include a forebay and a
drawdown orifice at permanent pool. Stormwater from greater storm events will bypass the
outlet that flows to the respective infiltration basin through either an outlet structure and
culvert or rip -rap spillway. The ponds have all been designed to have an emergency spillway
as well.
The infiltration basins have been designed to meet NCDENR requirements for an infiltration
basin in series. Pretreatment is provided by the wet detention ponds, the bottom has been
designed to be at least 1' above seasonal high water table (SHWT) elevation, and an emergency
spillway has been provided. A bottom surface area has been provided to infiltrate the water
quality volume at 1/z the measured infiltration rate within five (5) days.
During construction, sediment will be controlled by temporary silt fence, temporary diversion
ditches, temporary inlet protection, culvert crossings, and temporary construction entrances.
The wet ponds will serve as temporary sediment/skimmer basins.
Please find all reference material and calculations in the following pages of this report. Note
that some calculations have also been located on the plans for easy reference during
construction.
DESIGN METHOD
Hydrologic calculations have been performed utilizing HydroCAD version 10.0 software which
employs the USDA SCS Method. The 1-Year and 10-Year Type -III 24-hour storm rainfall depth
(precipitation data) has been taken from the NOAA Atlas 14 Precipitation Frequency Data
Server (PFDS). Curve Number (CN) and Time of Concentration (TOC) calculations have been
performed in accordance with the USDA TR-55 manual, with a minimum TOC of 5 minutes.
The difference in the Pre/Post 1-Year 24-hour storm volume of runoff has been computed
utilizing HydroCAD version 10.0 software and the SCS (TR-55) Method with composite curve
numbers.
Hydrologic Soil Group Classifications have been taken from the USDA Web Soil Survey.
Storm conveyance calculations have been performed utilizing the Rational Method within
Carlson Hydrology 2016 which employs the FHWA Method for HGL computations.

MAINTENANCE
Contractors shall be responsible for periodic inspection and maintenance of all indicated
erosion control devices in accordance with the plans and specifications. In addition, inspection
and any necessary maintenance will be required immediately following any significant storm
event. Any erosion control measure that fails to function as intended shall be repaired
immediately. Upon completion of construction and the establishment of stabilized ground
cover, the property owner shall be responsible for any on going site maintenance.

EROSION AND SEDIMENTATION CONTROL SPECIFICATION
PART1-GENERAL
1.1 RELATED DOCUMENT
A. Drawings and general provisions of the Contract, including General and Supplementary
Conditions and Division 1 Specification Sections, apply to this Section.
1.2 WORK INCLUDED
A. Contractor shall take every reasonable precaution throughout construction to prevent the
erosion of soil and the sedimentation of streams, lakes, reservoirs, other water impoundments,
ground surfaces, or other property as required by State and Local regulations.
B. Contractor shall, upon suspension or completion of land -disturbing activities, provide
protection covering for disturbed areas. Permanent vegetation shall be established at the
earliest practicable time. Temporary and permanent erosion control measures shall be
coordinated to assure economical, effective, and continuous erosion and sediment control
throughout the construction and post construction period.
1.3 RELATED SECTIONS
A. Related Sections - The following Sections contain requirements that relate to this Section:
1. 01011- Existing Underground Utilities
2. 01015 - Special Conditions for this Contract
3. 01070 - Shop Drawings, Project Data & Samples
4. 02200 - Earthwork, Excavation Trenching, and Backfilling
5. 02230 - Site Clearing
6. 02240 - Dewatering
7. 02485 - Seeding General Areas
1.4 REGULATORY REQUIREMENTS
A. Contractor shall be responsible for prevention of damage to properties outside the construction
limits from siltation due to construction of the project. The Contractor will assume all
responsibilities to the affected property owners for correction of damages that may occur.
Erosion control measures shall be performed by the Contractor, conforming to the requirements
of, and in accordance with plans approved by applicable state and local agencies and as per the
erosion control portion of the construction drawings and these specifications. The Contractor
shall not allow mud and debris to accumulate in the streets. Should the Contractor pump water
from trenches during construction, appropriate siltation preventative measures shall be taken
prior to discharge of pumped water into any storm drain or stream.

PART 2 - PRODUCTS
2.1 Open mesh biodegradable mulching cloth.
2.2 Fertilizer shall be 10-10-10 grade or equivalent.
2.3 Lime shall be dolomitic agricultural ground 1 limestone containing not less than 10 percent
magnesium oxide.
2.4 Phosphate shall be 20 percent super phosphate or equivalent.
2.5 Provide grass seed mixture as shown on the plans.
2.6 Silt fence shall consist of non -biodegradable filter fabric (Trevira, Mirafi, etc.) wired to
galvanized wire mesh fencing and supported by wood or metal posts.
2.7 NCDOT Class B stone for erosion control.
PART 3 - EXECUTION
3.1 CLEARING
A- Clearing and grubbing shall be scheduled and performed in such a manner that subsequent
grading operation and erosion control practices can follow immediately thereafter. Excavation,
borrow, and embankment operations will be conducted such that continuous operation. All
construction areas not otherwise protected shall be planted with permanent vegetative cover
within 7 working days after completion of active construction. All slopes shall be planted
within 14 calendar days after completion of such activity.
3.2 STABILIZING
A. The angle for graded slopes and fills shall be no greater than the angle that can be retained by
vegetative cover or other adequate erosion control devices or structures. All disturbed areas not
to be paved and left exposed will, within 14 calendar days of completion of any phase of
grading, be planted or otherwise provided with either temporary or permanent ground cover,
devices, or structures sufficient to restrain erosion. All slopes steeper than 3:1 shall be planted
or otherwise provided with either temporary or permanent ground cover, devices, or structures
sufficient to restrain erosion within 7 calendar days.
3.3 REGULATORY REQUIREMENTS
A. Whenever land disturbing activity is undertaken on a tract, a ground cover sufficient to restrain
erosion must be planted or otherwise provided within 7 calendar days on that portion of the
tract upon which further active construction is to being undertaken.
B. If any earthwork is to be suspended for any reason whatsoever for longer than 7 calendar days,
the areas involved shall be seeded with vegetative cover or otherwise protected against
excessive erosion during the suspension period. Suspension of work in any area of operation
does not relieve the Contractor of the responsibility for the control of erosion in that area.

PART 4 - CONSTRUCTION PHASE
4.1 PRACTICES
A. Avoid dumping soil or sediment into any streambed or watercourse. Backfill for stream
crossings shall be placed dry and compacted to minimize siltation of the watercourse, where
applicable.
B. Maintain an undisturbed vegetative buffer where possible between a natural watercourse and
trenching and grading operations.
C. Avoid equipment crossings of streams, creeks, and ditches where practicable.
PART 5 - SEDIMENT CONTROL FEATURES
5.1 GENERAL
A. All devices (silt fences, retention areas, etc.), for sediment control shall be constructed at the
locations indicated prior to beginning excavation on the site. All devices shall be properly
maintained in place until a structure or paving makes the device unnecessary or until directed
to permanently remove the device.
5.2 DESIGN APPLICATIONS
A. Mulch shall be used for temporary stabilization of areas subject to excessive erosion, and for
protection of seed beds after planting where required.
1. Jute, mesh, etc. should be installed as per manufacturer's instructions.
B. Silt fences shall be used at the base of slopes to restrict movement of sediment from the site.
C. Riprap shall be used at the proposed outfall pipes as indicated on plans.
D. Establish vegetative cover on all unpaved areas disturbed by the work.
1. Preparation of Seedbed. Areas to be seeded shall be scarified a depth of 6 inches until a
firm, well -pulverized, uniform seedbed is prepared. Lime, phosphorous, and fertilizer
shall be applied during the scarification process in accordance with the following rates.
a. Lime — 2 ton per acre
b. Nitrogen —100 pounds per acre
C. P2O5 — 200 pounds per acre
2. Seeding. Disturbed areas along roads and ditches shall be permanently seeded with 10-
20 pounds per acre of centipede during the period from March through September.
Seeding performed during the period from April to August shall be temporarily seeded
with 40 pounds per acre of German Millet. The permanent vegetative cover will be over
seeded at the earliest possible time as specified above.
3. Mulch all areas immediately after seeding. Mulch shall be applied and anchored as
specified hereinbefore.

5.3 MAINTENANCE
A. The Contractor shall be responsible for maintaining all temporary and permanent erosion
control measures in functioning order. Temporary structures shall be maintained until such
b1ne as vegetadori is firmly established and grassed areas shall be maintained until completion
of the project. Areas which fail to show a suitable stand of grass or which are damaged by
erosion shall be immediately repaired.
5.4 REMOVAL OF SEDIMENT CONTROL DEVICES
A. Near completion of the project, when directed by the Owner's agent, the Contractor shall
dismantle and remove the temporary devices used for sediment control during construction.
All erosion control devices in seeded areas shall be left in place until the grass is established.
Seed areas around devices and mulch after removing or filling temporary control devices.
END OF SECTION 02410

SOILS MAP

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Hydrologic Soil Group—Pender County, North Carolina
Main Tract
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Ponder County, North Carolina (NC141)
Map unit symbol
Map unit name
Rating
Acres in AOI
Percent of AOI
LnA
Leon fine sand, 0 to 2
percent slopes
A/D
22.4
23.1 %
Ma
Mandarin fine sand
B/D
35.3
36.5%
Mu
Murville muck
A/D
39.1
40.40%
Totals for Area of Interest
96.8
100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and VD). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 1/11/2016
� Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group—Pender County, North Carolina
Main Tract
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. • None Specified
Tie -break Rule: Higher
LISDA Natural Resources Web Soil Survey 1/11/2016
Conservation Service National Cooperative Soil Survey Page 4 of 4

REFERENCE DATA

1/11/2016 Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3 A
(@ Location name: Hampstead, North Carolina, US*
Latitude: 34.4628*, Longitude:-77.5744*
Elevation: 36 tt*
source: Google Maps
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average recurrence interval (years) ,
Duration
1
2 5 10
25 50 100 200 500 1000
-��
5�nm
0.500
(0.464-0.542)
-O.-59-471 0.695 0.774
(0.550-0.643) (0.642-0.751) (0.713-0.836)
0.873 0.949 1.03 1.10 1.20 128
(0.801-0.942) (0.867-1.02) (0.931-1.11) (0.995-1.19) (1.07-1.30) (1.14-1.39)
0.799
0.950 1.11 1.24
1.39 1.57 1.63 1.75 1.90 2.02
10�nin
(0.740-0.865)
(0.880-1.03) (1.03-1.20) (1.14 1.34)
(1.28-1.50) (1.38-1.63) (1 AB-1.76) (1.58-1.89) (1.70-2.06) (1.79 2.19)
1.19 1A1 1.56
1.76 1.97 2.06 220 2.39 2.54
15�nin
..999
(0.925-1.08)
1 (1.11-1.29) (1.30-1.52) 11 1.44-1.69)
(1.62-1.90) (1.75-2.06) (1.87-2.22) (1.99-2.38) (2.14-2.59)`(2.25-2.751
1.37
1.65 2.00 2.27
2.61 2.88 3.16 3A3 3.87 4.17
[��in
(1.27-1.48)
(1.53-1.79) (1.85-2.16) (2.09-2A5)
(2.40-2.82) (2.63-3.11) (2.87-3.40) (3.10 3.71)�(3.40-4.13)1(3.64-4A )I
60�nin
��
1.71
(1.58-1.85)
2.07 2.56 2.95
(1.92-2.24) (2.37-2_77)_I (2.72_3.19)
4.35 SA6 6.00
3A8 =(34.21)
(3.19-3.75) (3.95-4_69) F(�.374-5(4.88_5.92)(5.31 6.51)
III
2.08
2.54 323
.79
6.82528 602
4.60 i
898
F2alr
226)
(2.342.76) (3.484.13)
2
)897
769.79)
(4.205.00) (4.80-5.73)(_3654) 7.40
01.92
[:�3]r
2.24
(2.06-2.45)
2.73 3A9 4.13
(2.52-3.00� (3.21-3.82) (3.78-4.52)
5.08 5.90 6.80 7.79 929 10.6
(4.62-5.54) (5.33-6.43) (6.09-7.41) (6.92-8A9) (8.14-10 ) (9.18-1 1.6)
2.74
3.35
429
5.08
627
7.30
T SA4 T
9.71 7F
17.6
13.3
6-hr
(2,51-3.02)
11 (3.07-3.69}-•
(3.91-4.73)
(4.63-5.60)
(5.67-6.89)
(6.55-8.01)
(7.51-9.25)
(8.55-10.6)
(10.1 12.8)1(11.4-14.6)
12fir
323
(2.93-3.60)
3.94
(3.58 4.39)
=(4Z5.65)
6.06
(5.46 6.73)
7.53
(6.73-8.33)
8.81
(7.82-9.73)
10.3
(9.02-11.3)
11.9
(10.3-13.1)
14A
(12.3 15.9)
16.6
(14.0 18.3)
3.72
4 51
5 84
6.99
8.73
10.3
12.0
13.9
16.9
19 A
24-hr
(3A2-4.09)
(4.15-4.97)
(5.36-6A2)
(6.38-7.66)
(7.89-9.55)
(9.19-11.2)
(10.6-13.1)
(12.2-15.3)
(14�4-18.6)
(16A-21.6)
2ilay
4 34
4.77)
525
(4.82-5.78)
6.74
(6.16 7.42)
8.02
(7.30-8.82)
9.98
(9.01 11.0)
11.7
(10.5 12.9)
13.6
(12.0-15.0)
=15F-19--17122.0(3.98
(16.3-21.3)
(18.4-24.6)
4.59
5.55
7.09
8.39
10.4
12.1
9 3.9
7 6.0
19.3
22.1
3�lay
(4.22-5.04)
(5.10-6.10)
(6.49-7.78)
(7.66-9.21)
(9.37-11.4)
10.8 1
(3_2)
(12.4-15.3)
(.7)
14.1-17
(16.6-21.4)
(18.7-24.7)
11
4.85
5.86
7A4
8.77
10.7 7F
12.4 7F
14.37F
16.37F
19.57F
222
4�lay
(4.46-5.31).
(5.39 6.42)
(6.82-8.15)
(8.01-9.60)
(9.73-11.7)
(11.2-13.6)1
(12.7-15.6)
(14A-17.9)
(16.8-21.6)
(18.9-24.8)
6.74
8A7
9.91
12.0
13.8
15.7
17.7
20.7
23 3
=5.59
7-day(5.17-6.08)
(6.23-7.32)
(7.82-9.20)
11 (9.12-10.8)
(11.0-13.0)
(12.5-14.9)
(14.1-17.1)
(15.8-19.3)
(18.2-22.8)
(20.1-25.7)
lA7
926
10.7
12.914.7
18.7
21.7
242
FO-day624
(5.78-6.77)
(6.93-8.12)
(8.57-10.0)
(9.91 11.7)
(11i8-14.0)
(13.4-15.9)
(15.0-18.1)
(16.7-20.4)
(19.1-23.8)
(21.0-26.7)
827
9.86
1 F-1-25--T-1-38
16.3
1SA
20.5
22.9
26.1
28.8
20�a
(7.73 8.89)
(9.20 10.6)
(11.2 12.9)
(12.8-14.8)
(15.0-17.5)
(162-1937
(18.7-22.1)
(20.6-24.7)
(23.2-28.4)
(25.3-31.5)
4A1
191
3
23.5
31 A2
30 day
(9.51-10.8)
12.0i
(11.3-12.8)
(13.615.4)
5160.1
.
)
(19
21.7-25.1)(23.627.7)26.2-A5
3)(28.2
34.1)
12.7
15.0
17.9
202
23A
26.0
28.7
315
35.3
382
45{lay
(11.9-13.6)
(14.1-16.1)
(16.8-19.1)
(18.9 21.6)
(21.8-25.1)
(24.1 27.9)�
(26.5-30.8)
(28.8-33.8)
(31.9-38.1)
(34.3-41.6)
"A
18.7
21.3
23.8
27.2
29.9
32.6
35 3
38.9
41.7
=60-day
(14.5-16.3)
(17.1-19.3)�
(20.1-22.6)
(22.4-25.3)
(25.5 28.9)
(28.0-31.8)
(30.3-34.7)
(32.6-37.7)
(35.7-41.8)
(37.9-45.0)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency
estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at
upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Ton
PF graphical
http:/Ihdsc.nws.rKm.gov/hdsctpfdslpfds jxir tpage.htm I?lat=34.4628&Ion=-77.5744&data=depth&ur its=english&series=pds 1/4

USGS MAP

ZUSGS U.S. DEPARTMENT OFTH.SUE RVINTERIOR HOLLY RIDGE QUADRANGLE
USTopo
U. & GEOLOGICAl — �OLINA
IIV
WE CAMP Liijrum
WEST 91TV x4 ol
oo
olp
-10
-17
pas—u
SITE
.15
-14
'12
41
SCALE 1:24 ON
. ........... . ...... . ........ ......... ..............
.................. 4
HOLLY RIDGE, NC

STORMWATER CALCULATIONS
OVERALL

Project Name: Surf City K-8
Client: LS3P
Project Number: 15348.PE
Prepared By: DJF
Date: 5/10/16
Wet Detention Basin / Infiltration Basin or LS-VFS in Series
1 yr. 24 hour Pre / Post: SCS (TR-55) Method
1
2
3
4
Rainfall Depth (1yr. 24hr.) [in.] =
3.72
3.72
3.72
3.72
Drainage Area to System [Ac.] =
10.82
4.83
9.90
4.52
SCS TR-55 Method Pre [cf] =
28,325
19,078
35,104
17,834
Reference HydroCAD Node
1S
2S
4S
3S
SCS TR-55 Method Post V-1 =
96,041
39,337
65,168
45,061
9L
10L
11S
12S
SCS TR-55 Method Pre/Post [cf] =
67,716
20,259
30,064
27,227

10S 50S 6S 3S 12S
PRE DA 1 POST 11 ST 1 B PRE DA 4 POST DA 4
9L
POST DA 1
2S 7S 8S 4S 11 S
PRE DA 2 POST 2� JOST 2B PRE DA 3 POST DA 3
Z10L
POST DA 2
Sub4 Reach L8

15348.PE 1-YR PRE POST COMP Type /// 24-hr 9-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Poe 2
Summary for Subcatchment 1S: PRE DA 1
Runoff = 1.98 cfs @ 13.64 hrs, Volume= 28,325 cf, Depth= 0.72"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
3.461
36
Woods, Fair, HSG A
1.947
60
Woods, Fair, HSG B
5.408
79
Woods, Fair, HSG D
10.816
62
Weighted Average
10.816
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
106.7 1,600 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment IS: PRE DA 1
Hydrograph
❑ Runoff
2 - - RunofF='i.98 Cfs @ 13.04 hrs
Ty0e III 24-hr
1 Year; Rainfall 3.72'T'
Ruhoff AreaT10.816 ac
Runoff Vollume=28,325 cf
Runoff Depth=10.72"
3
1=1owLength=1,S00'
0 Plope==0.0925 7'
Tc-106.7 min
GN=6�
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type Hi 24 hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD®10.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 2S: PRE DA 2
Runoff = 1.49 cfs @ 13.57 hrs, Volume= 19,078 cf, Depth= 1.09"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.145
36
Woods, Fair, HSG A
2.270
60
Woods, Fair, HSG B
2.414
79
Woods, Fair, HSG D
4.829
69
Weighted Average
4.829
100.00% Pervious Area
Tc
min
110.0
Length Slope Velocity Capacity Description
1,650 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 2S: PRE DA 2
Hydrograph
Runpff--j.49 qfs @ 13.47 hr$
Tyo III !24-hf
1�Year Rainfall�3.72"
Runoff;Ared=4.829 ad
Runod Voume=19,78 f
Rungff Depth=1.09"
Plow Length='1,650`
Plope,=0.0925 7,,
Tc-1'1110.0 mini
GN=60
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
0 Runoff

15348.PE 1-YR PRE POST COMP Type III 24-hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCADO 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 3S: PRE DA 4
Runoff = 1.41 cfs @ 13.52 hrs, Volume= 17,834 cf, Depth= 1.09"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.181
36
Woods, Fair, HSG A
2.076
60
Woods, Fair, HSG B
2.257
79
Woods, Fair, HSG D
4.514
69
Weighted Average
4.514
100.00% Pervious Area
Tc
min
106.7
v
0
a
Length Slope Velocity Capacity Description
(feet) (ft/ft) (ft/sec) (cfs)
1,600 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 3S: PRE DA 4
Hydrograph
1 4'
Runoff=1.41 cfs @ 13.52 hrs
Ty0e III 24-hr
1�Year, Rai6fall=3.72'1
Runoff Arm=4.514 ad-
Runotf Volume=17,$34 cf
Runoff DOpth=11.09"
Plow' Length=i,60W
Slope;=0.0925 '/,'
Tc�106.7 mini
CN=66
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
❑ Runoff

15348.PE 1-YR PRE POST COMP Type I// 24-hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD®10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Paae 5
Summary for Subcatchment 4S: PRE DA 3
Runoff = 2.66 cfs @ 13.57 hrs, Volume= 35,104 cf, Depth= 0.98"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
1.188
36
Woods, Fair, HSG A
3.764
60
Woods, Fair, HSG B
4.952
79
Woods, Fair, HSG D
9.904
67
Weighted Average
9.904
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
110.0 1,650 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
0
1
Subcatchment 4S: PRE DA 3
Hydrograph
❑ Runoff
RunpfF4.66 cfs @ 13.07 hrS
Ty0e III'24-he
1 Year: Rainfall=,3.72'' _
R4noff;Area=9.904 ad
kunoi' Volume=35i,104 cf
kundff Depth=,0.98"
rlowl Lentith=1,650'
sl0pe=O.OQ2.5_'/'_
Tc�110.0 min
ON=0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type/1/ 24 hr 9-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCADO 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 6
Summary for Subcatchment 5S: POST 1A
Runoff = 5.25 cfs @ 13.40 hrs, Volume= 59,744 cf, Depth= 2.38"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
1.169
98
Paved parking, HSG A
0.657
98
Paved parking, HSG B
1.826
98
Paved parking, HSG D
0.321
98
Water Surface, 0% imp, HSG A
0.181
98
Water Surface, 0% imp, HSG B
0.502
98
Water Surface, 0% imp, HSG D
0.722
39
>75% Grass cover, Good, HSG A
0.406
61
>75% Grass cover, Good, HSG B
1.128
80
>75% Grass cover, Good, HSG D
6.912
87
Weighted Average
3.260
47.16% Pervious Area
3.652
52.84% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
106.7 1,600 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 5S: POST 1A
Hydrograph
❑ Runoff
- Runuffff=$35;%413.40 firs
Ty0e III �24-h�
11Year, Rainfa1111_=3.72'1
4
_ _
RunofflAred=6.012 ad
Ikunotf Vollume=59,M4 ct
Runoff Ue h— .3V!-
3
Flow' Length=1,600`
$lope;=0.0�25-'l;'-
2
Tc=106.7 min
GN=87
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type 11124-hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydmCAD®10.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment 6S: POST 1 B
Runoff = l l .99 cfs @ 12.07 hrs, Volume= 36,297 cf, Depth= 2.56"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.646
98
Paved parking, HSG A
0.364
98
Paved parking, HSG B
1.010
98
Paved parking, HSG D
0.265
98
Water Surface, 0% imp, HSG A
0.149
98
Water Surface, 0% imp, HSG B
0.414
98
Water Surface, 0% imp, HSG D
0.338
39
>75% Grass cover, Good, HSG A
0.190
61
>75% Grass cover, Good, HSG B
0.528
80
>75% Grass cover, Good, HSG D
3.904
89
Weighted Average
1.884
48.26% Pervious Area
2.020
51.74% Impervious Area
Tc Length Slope Velocity Capacit!
min) (feet) (ft/ft) (ft/sec) (cfs
5.0
Description
Direct Entry,
Subcatchment 6S: POST 1 B
Hydrograph
13
12
- - - - -
tuno,-"— 1.99 ds @ 12.g7 hrs
- --
11
- - -'-- -r--------'-- ---*-
---r---�-Tyke III'24-h�
10
•r
1--Year Rainfall=3.72{
y
RwnoffE Areej=3.9104 ad
w g
- - -- -- --- --i---
KUn-C fVolume=S6, 97 cif
.. 7
- - --- --,--- -- ---
- - - - - - - Runoff Depth=2:56" -
- ---- - --- ,------
-1`c=3bmin-
c6
--i-
- - M"wY
3
2
-- -`--- -�--- '_
1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
❑ Runoff

15348.PE 1-YR PRE POST COMP Type 111 24 hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 8
Summary for Subcatchment 7S: POST 2A
Runoff = 2.89 cfs @ 13.45 hrs, Volume= 33,736 cf, Depth= 2.38"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.068
98
Paved parking, HSG A
1.070
98
Paved parking, HSG B
1.138
98
Paved parking, HSG D
0.003
98
Water Surface, 0% imp, HSG A
0.047
98
Water Surface, 0% imp, HSG B
0.049
98
Water Surface, 0% imp, HSG D
0.046
39
>75% Grass cover, Good, HSG A
0.718
61
>75% Grass cover, Good, HSG B
0.764
80
>75% Grass cover, Good, HSG D
3.903
87
Weighted Average
1.627
41.69% Pervious Area
2.276
58.31% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
110.0 1,650 0.0025 0.25 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
Subcatchment 7S: POST 2A
Hydrograph
-- 0 Runoff
Runoff=g.89 Cfs @ 13.45 hrs
Ty0e III�24-ht
1-Year Rainfall 3.72''
Runoff-'Aree-3.910.3 ac-
�. 2 Runoff Volume=33,736 cf
c Runoff Depth ;2.38"
3 Plow' Length=1,650'
$1ope=0.0925 T
1 Tc=11 AM11n
GN=87
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type 111 24 hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD®10.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 9
Summary for Subcatchment 8S: POST 2B
Runoff = 1.86 cfs @ 12.08 hrs, Volume= 5,602 cf, Depth= 1.67"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac)
CN
Description
0.000
98
Paved parking, HSG A
0.000
98
Paved parking, HSG B
0.000
98
Paved parking, HSG D
0.008
98
Water Surface, 0% imp, HSG A
0.132
98
Water Surface, 0% imp, HSG B
0.141
98
Water Surface, 0% imp, HSG D
0.019
39
>75% Grass cover, Good, HSG A
0.303
61
>75% Grass cover, Good, HSG B
0.323
80
>75% Grass cover, Good, HSG D
0.926
78
Weighted Average
0.926
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
5.0
v
0
Direct Entry,
Subcatchment 8S: POST 2B
Hydrograph
24
11 - -w-
Runjofl='q.86 ifs (6 112.Q8 hr$
Ty0e III 24-hi
1 Year; Rainfall=3.72'!
RunoffAre4=0.926 ad
Runoff V61ume=5,602 cf
a .. Runoff_ Depth=1.677,_
CN=7$
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
0 Runoff

15348.PE 1-YR PRE POST COMP Type 11124 hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
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Summary for Subcatchment 11 S: POST DA 3
Runoff = 21.76 cfs @ 12.08 hrs, Volume= 65,168 cf, Depth= 1.81"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.421
98
Paved parking, HSG A
1.335
98
Paved parking, HSG B
1.756
98
Paved parking, HSG D
0.054
98
Water Surface, 0% imp, HSG A
0.172
98
Water Surface, 0% imp, HSG B
0.226
98
Water Surface, 0% imp, HSG D
0.713
39
>75% Grass cover, Good, HSG A
2.257
61
>75% Grass cover, Good, HSG B
2.970
80
>75% Grass cover, Good, HSG D
9.904
80
Weighted Average
6.392
64.54% Pervious Area
3.512
35.46% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 11 S: POST DA 3
Hydrograph
-- ----- - - -
24
-I- _ _. L _ _ _ _ _ _ _ -I- _ _ _ _ _. i __ _ _ _. _ _ _ _�- _ _ _ - - - _ _ _ .. _
❑ Runoff
22
- - - - -; - Rungff=21(a� ..76 cfs _12.Q8 hrs _
20
Ty0e III'24-hr
18
1�Year Rainfa11=3.72?
*
- - - - - Runoff Aree=J.9104 at
_
J - -
- - - - flu noi�f Vol u me=65, �68 cf -
14
FWnof#-Depth=1:81','
3 12
Tc=5.0 min
10
CN=8p
8
6
4
2
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type 1N24-hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
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Summary for Subcatchment 12S: POST DA 4
Runoff = 14.71 cfs @ 12.07 hrs, Volume= 45,061 cf, Depth= 2.75"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Type III 24-hr 1-Year Rainfall=3.72"
Area (ac) CN Description
0.110
98
Paved parking, HSG A
1.267
98
Paved parking, HSG B
1.377
98
Paved parking, HSG D
0.026
98
Water Surface, 0% imp, HSG A
0.299
98
Water Surface, 0% imp, HSG B
0.325
98
Water Surface, 0% imp, HSG D
0.044
39
>75% Grass cover, Good, HSG A
0.511
61
>75% Grass cover, Good, HSG B
0.555
80
>75% Grass cover, Good, HSG D
4.514
91
Weighted Average
1.760
38.99% Pervious Area
2.754
61.01% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 12S: POST DA 4
Hydrograph
16❑ Runoff
--- -- ----- ---------- -lRnngff=44.T'I-rf @42. 7-h
14-
Ty0e III 24-hir
12 - - - -1� ears Ra'l-'3:720 -
Rwnoff Aree=4414 at
w 10 - - - - - - - - I�unow Volume=45,b61 cf
- - - - - Runoff Depth=2.75" -
3 8 Yc=5.0 min
p
u- 6 -
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

15348.PE 1-YR PRE POST COMP Type /// 2447r 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
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Summary for Link 9L: POST DA 1
Inflow Area =
471,145 sf,
52.44% Impervious,
Inflow Depth = 2.45" for 1-Year event
Inflow =
12.84 cfs @
12.07 hrs, Volume=
96,041 cf
Primary =
12.84 cfs @
12.07 hrs, Volume=
96,041 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
1
1
1
3
0
Link 9L: POST DA 1
Hydrograph
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
❑ Inflow
❑ Primary

15348.PE 1-YR PRE POST COMP Type 111 24 hr 1-Year Rainfall=3.72"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
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Summary for Link 10L: POST DA 2
Inflow Area =
210,351 sf,
47.13% Impervious,
Inflow Depth = 2.24" for 1-Year event
Inflow =
3.05 cfs @
13.44 hrs, Volume=
39,337 cf
Primary =
3.05 cfs @
13.44 hrs, Volume=
39,337 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 0.00-72.00 hrs, dt= 0.010 hrs
Link 10L: POST DA 2
Hydrograph
❑ Inflow
❑ Primary
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

STORMWATER CALCULATIONS
WET PONDS

Project Name: Surf City K-8
Client:
LS3P
Project Number:
15348.PE
Prepared By:
DJF
Date:
4/25/16
Average Depth Calculation: (Option 2 per Errata)
Pond #f
ABottom shelf =
68,435
sf
ABottom Pond =
37,450
sf
APerm Pool =
79,80.0
sf
Depth =
4.00
ft
davg =
3.6
ft
Pond #2
ABottom shelf =
9,020
sf
ABottom Pond =
3,690
sf
APerm Pool =
16,580
sf
Depth =
5.00
ft
day =
3.9
ft
Pond #3
ABottom shelf =
15,645
sf
ABottom Pond =
6,625
sf
APerm Pool =
19,660
sf
Depth =
4.00
ft
day =
3.3
ft
Pond #4
ABottom shelf =
21,660
sf
ABottom Pond =
7,000
sf
APerm Pool =
28,320
Sf
Depth =
4.00
ft
dav9 =
3.1
ft
-'ARA M OUN TE
i N C% i N } i rs 1 N [:, i N C9.

Surf City K-8 : Wet Pond #1
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 10.816 ACRE Value from CAD
Impervious Drainage Area 5.673 ACRE Value from CAD
Impervious Cover 52.45% Impervious Cover=(Impervious Drainage
Area)/(Total Drainage Area) 100%
Elevation of Permanent Pool Surface
35.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
(Bottom Elevation)=(Permanent Pool Surface
Elevation of Wet Detention Pond Bottom
30.0
FT
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
680
FT
Value from CAD
Approximate Pond Width
117
FT
value tram CAD
Len th:Width Ratio
5.8:1
Ratio=(Length)/(Width):1
Required SA/DA Ratio for 90% TSS Removal 5.25 value tram cnart. mererence: ­uuio tzizi Kemovat
Required Permanent Pool Surface Area 24,734 SF Required Surface Area=(Required SA/DA
Ratio) *(Total Drainage Area)
Provided Permanent Pool Surface Area 79,800 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv
0.522 IN/IN
Rv=0.05+0.009*(110 Impervious)
1.5" Runoff Volume (Volume of Temporary Pool)
30,743 CF
1.5" Runoff Volume=1.5 inch*Rv*1 fo 02
inch*(Total Drainage Area)
SCS TR-55 Method Required Runoff Volume
67,716 CF
[see HydroCAD calculation]
(Pre/Post Volume difference of 1-Year storm)
Volume Below Permanent Pool
303,120 CF
Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled
370,836 CF
Total Volume to be Controlled=(Volume Below
Permanent Pool)+(Required Runoff Volume)
Storage Elevation at Required SCS Volume
35.82 FT
Value is interpolation based upon stage-storage7
values. See stage -storage calculations
Step 3: Calculate the required frebay volume (18-22% of total pond volume) and compare to the frebay volume provided
Total Pond Volume
303,120 CF
Value from stage -storage calculations
Required Total Forebay Volume
54,562 CF
Forebay Volume= Total Pond Volume *18%
Provided Total Forebay Volume
62,480 CF
Value from stage -storage calculations
(Provided Forebay Volume)/(Total Pond
Provided Forebay Volume:Total Pond Volume
20.6%
Volume)*100%

Step 4A: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
5.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.83
FT
Value chosen by designer
Total Elevation Head Above Orifice
0.83
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Onfrce)=((Storage
Average Elevation Head Above Orifice
0.28
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.35
CFS
Q=Cd*(Pi)*((Diameter of Orifice)*(1 ft/12
fn)]^2/4*(2*32.2*(Averge Head)]111/2
Drawdown Time for Req'd WQV
2.27
DAYS
(Drawdown Time)=(Required Runoff Volume)/Q*(1
Step 4B: Verify that time required to drawdown the provided runoff volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
5.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.90
FT
Value chosen by designer
Total Elevation Head Above Orifice
0.90
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.30
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.36
CFS
Q =Cd*(Pi) *[(Diameter of Orifice) *(1 ft/12
in)] 2/4 j2 32.2 Av Head)]^1/2
Drawdown Time for Provided WQV
2.38
DAYS
(Drawdown Time)=(Provided Runoff Volume)/Q*(1

Surf City K-8 - Wet Pond #1
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
3
35.00
79,800
0
0 Permanent Pool
q
36.00
85,655
82,728
82,728
?JS•q
37.00
91,630
88,643
171,370
CO
38.00
97,710
94,670
266,040
3
38.50
100,795
49,626
315,666
Stage/Storage Main Pond (Not Including Forebays)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
27.0
27,135
-
--Sediment Storage
28.0
30,385
-
-
29.0
33,820
-
-
30.0
37,450
0
0 -Bottom Elev.
31.0
41,230
39,340
39,340
32.0
45,160
43,195
82,535
33.0
49,235
47,198
129,733
34.0
54,655
51,945
181,678
35.0
63,270
58,963
240,640 -Permanent Pool
Stage/Storage Total Pond (Including Forebay)
Main Pond
Cumulative
Volume
Forebay #1
Forebay #2
Forebay #3
Volume, S
Contour
(CF)
Volume (CF)
Volume (CF)
Volume (CF)
(CF)
27.0
0
0
0
0
0
28.0
0
1,530
0
875
2,405
29.0
0
3,685
0
2,158
5,843
30.0
0
6,575
0
3,920
10,495
31.0
39,340
10,320
0
6,233
55,893
32.0
82,535
15,050
413
9,163
107,160
33.0
129,733
20,895
1,118
12,780
164,525
34.0
181,678
27,985
2,188
17,153
229,003
35.0
240,640
36,445
3,690
22,345
303,120
Forebay #1
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
780
-
-Sediment Storage
27.0
1,245
0
0 -Bottom Elev.
23.0
1,815
1,630
1,530
29.0
2,495
2,155
3,685
30.0
3,285
2,890
6,575
31.0
4,205
3,745
10,320
32.0
5,255
4,730
15,050
33.0
6,435
5,845
20,895
34.0
7,745
7,090
27,985
35.0
9,175
8,460
36,445 -Forebay Volume
82?Z D
a2
I
-74455

Surf City K-8 - Wet Pond #1
Stage -Storage Calculations for Proposed Wet Detention Pond
Forebay #2
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
30.0
110
-
-
--Sediment Storage
31.0
285
0
0
Bottom Elev.
32.0
540
413
413
33.0
870
705
1,118
34.0
1,270
1,070
2,188
35.0
1,735
1,503
3,690
+-ForebayVolume
Forebay 03
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
20.0
395
-
—Sediment Storage
27.0
690
0
0
Bottom Elev.
28.0
1,060
875
875
29.0
1,505
1,283
2,158
30.0
2,020
1,763
3,920
31.0
2,605
2,313
6,233
32.0
3,255
2,930
9,163
33.0
3,980
3,618
12,780
34.0
4,765
4,373
17,153
35.0
5,620
5,193
22,345
••Forebay Volume

Project Name: Surf City K-8 School - -- -- - I -- --
Client: Pender County Schools pI-IL M at1N
Project Number: 15348.PE
Prepared By: DJF
Date: 4/26/16
Forebay Percentage Calculation: (Per NCDENR SWM BMP Manual Section 10.3.3)
Overall BMP (WET POND #1)
Drainage Area = 10.816 Acres
Total Forebay Vol. = 62,480 cf
Forebay #1
Drainage Area =
6.270 Acres
58% of total drainage area
Forebay Volume =
36,445 cf
58% of total forebay volume
Forebay #2
Drainage Area =
0.650 Acres
6% of total drainage area
Forebay Volume =
3,690 cf
6% of total forebay volume
Forebay #3
Drainage Area =
3.896 Acres
36% of total drainage area
Forebay Volume =
22,345 cf
36% of total forebay volume

Surf City K-8 - Wet Pond 92
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a hvebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 4.830 ACRE Value from CAD
Impervious Drainage Area 2.276 ACRE Value from CAD
Impervious Cover 47.12% Impervious Cover -(Impervious Drainage
Area)/(Total Drainage Area)*100%
Elevation of Permanent Pool Surface
33.00
FT
Value selected by designer
Depth of Permanent Pool
6.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
27.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation)-(Depth of Permanent Pool)
Approximate Pond Length
FT
Value from CAD
Approximate Pond Width
FF
FT
Value from CAD
Len h:Width Ratio
3.9:1
Ratio= Len th 1 Width :1
Required SAIDA Ratio for 90% TSS Removal 4.07 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 8,562 SF Required Surface Area=(Required SAIDA
Ratio) *(Total Drainage Area)
Provided Permanent Pool Surface Area 16,580 SF Interpolated value from stage -storage calculations
Step 2. Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.474 WIN Rv--0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 12,466 CF 1.5" Runoff Volume=1.5 inch*Rv*1 foot/12
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
Volume difference of 1-Year storm)
20,259 CF [see 1-lydroCAD calculation]
Volume Below Permanent Pool 52,630 CF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 72,889 CF Total Volume to be Controlled=(Volume Below
Permanent Pool + Required Runoff Volume
Storage Elevation at Required SCS Volume 34.11 FT Value is interpolation based upon stage -storage
values. See staae�stomoe calculations
Step 3. Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume provided
Total Pond Volume 52,630 CF Value from stage -storage calculations
Required Total Forebay Volume 9,473 CF Forebay Volume= otal Pond Volume *18%
Provided Total Forebay Volume 10,588 CF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 20.1% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Outlet Structure
34.11
FT
Value chosen by designer
(Total Elevation Head Above Orifice)=(Weir
Total Elevation Head Above Orifice
1.11
FT
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Elevation at Required Volume)+(Elevation of
Average Elevation Head Above Orifice
0.37
FT
Permanent Pool Surface)p3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Peak Flowrate Through Low -flow Orifice
0
CFS
[See H droCAD Calculation]
Drawdown Time for Re 'd WQV
3.02
DAYS
See H droCAD Calculation

Surf City K-8 - Wet Pond #2
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
33.00
16,580
0
0 FPermanent Pool
34.00
19,420
18,000
18,000
35.00
22,380
20,900
38,900
36.00
25,"0
23,910
62,810
37.00
28,625
27,033
89,843
StagelStorage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
2,885
0
0 • Sediment Storage
27.0
3,690
0
0 *-Bottom Elev.
28.0
4,580
4,135
4,135
29.0
6,680
5,630
9,765
30.0
8,435
7,558
17,323
31.0
10,350
9,393
26,715
32.0
12,450
11,400
38,115
33.0
16,580
14,515
52,630 •Permanent Pool
Forebay
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
570
-.Sediment Storage
29.0
1,135
0
0 -Bottom Elev.
30.0
1,835
1,485
1,485
31.0
2,600
2,218
3,703
32.0
3,430
3,015
6,718
33.0
4,310
3,870
10,588 •forebay Volume

Surf City K-8 - Wet Pond #3
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3:1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 9.904 ACRE Value from CAD
Impervious Drainage Area 3.512 ACRE Value from CAD
Impervious Cover 35.46% Impervious Cover --(Impervious Drainage
Area)/(Total Drainage Area) 100%
Elevation of Permanent Pool Surface
30.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
(Bottom Elevation)=(Permanent Pool Surface
Elevation of Wet Detention Pond Bottom
25.0
FT
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
FT
Value from CAD
Approximate Pond Width
77
FT
Value from CAD
Len th:Width Ratio
3.3:1
Ratio= Len h / idth :1
Required SAIDA Ratio for 90% TSS Removal 3.55 Value tram chart. Heterence: 'WU76 l SS Hemoval
Required Permanent Pool Surface Area 15,315 SF Required Surface Area=(Required SAIDA
Ratio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 19,660 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.369 WIN Rv=0.05+0.009*(% impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 19,909 CIF 1.5" Runoff Volume=1.5 inch*Rv*1 1oot/12
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
30,064 CIF
[see HydroCAD calculations]
Volume difference of 1-Year storm)
Volume Below Permanent Pool
62,503 CIF
Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled
82,411 CIF
Total Volume to be Controlled=(Volume Below
Permanent Pool)+(Required Runoff Volume
Storage Elevation at Required SCS Volume
31.41 FT
Value is interpolation based upon stage -storage
values. See stave -storage calculations
Step 3: Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume provided
Total Pond Volume
62,503 CIF
Value from stage -storage calculations
Required Total Forebay Volume
11,250 CIF
Forebay Volume= Total Pond Volume *18%
Provided Total Forebay Volume
12,625 CIF
Value from stage -storage calculations
(Provided Forebay Volume)/(Total Pond
Provided Forebay Volume:Total Pond Volume
20.2%
Volume)*100

Step 4: Verify mat time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
4.00
IN
Value chosen by designer
Elevation of Outlet Structure
31.41
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.41
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=[(Storage
Average Elevation Head Above Orifice
0.47
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Peak Flowrate Through Low -flow Orifice
0.47
[See HydroCAD calculations
Drawdown Time for WQV Runoff
2.92
DAYS
[See HydroCAD calculations

Surf City K-8 - Wet Pond #3
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
30.00
19,660
0
0 *-Permanent Pool
31.00
21,795
20,728
20,728
32.00
24,000
22,898
43,625
33.00
26,260
25,130
68,755
34.00
28,575
27,418
96,173
35.00
30,950
29,763
125,935
35.50
32,160
15,778
141,713
Stage/Storage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
6,180
-
- -Sediment Storage
25.0
7,585
0
0 -Bottom Elev.
26.0
9,185
8,385
8,385
27.0
10,995
10,090
18,475
28.0
13,055
12,025
30,500
29.0
15,645
14,350
44,850
30.0
19,660
17,653
62,503 -Permanent Pool
Forebay 91
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
590
-
- -.Sediment Storage
25.0
960
0
0 Bottom Elev.
26.0
1,435
1,198
1,198
27.0
2,030
1,733
2,930
28.0
2,785
2,408
5,338
29.0
3,625
3,205
8,543
30.0
4,540
4,083
12,625 •-Forebay Volume

Surf City K-8 - Wet Pond #4
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a foebey that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 4.516 ACRE Value from CAD
Impervious Drainage Area 2.755 ACRE Value from CAD
Impervious Cover 61.00% Impervious Cover --(Impervious Drainage
Area)/(Total Drainage Area)*100%
Elevation of Permanent Pool Surface
34.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
29.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation) -(Depth of Permanent Poo!)
Approximate Pond Length
400
FT
Value from CAD
Approximate Pond Width
71
FT
Value from CAD
Len h:Width Ratio
5.6:1
Ratio= Len th 1 Width :1
Required SA/DA Ratio for 90% TSS Removal 7.11 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 13,986 SF Required Surface Area=(Required SA/DA
Ratio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 28,320 SF Interpolated value from stage -storage calculations
Step 2. Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.599 IN/IN Rv=0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 14,729 CF 1.5" Runoff Volume=1.5 inch*Rv*1 foot,112
inch*(Total Drainage Area)
SCS Method Required Runoff Volume (Pre/Post
Volume difference of 1-Year storm)
27,227 CF [see I-IydroCAD calculations]
Volume Below Permanent Pool 81,905 CF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 109,132 CF Total Volume to be Controlled=(Volume Below
Permanent Pool) + Required Runoff Volume
Storage Elevation at Required Volume 34.90 FT Value is interpolation based upon stage -storage
values. See stage -storage calculations
Step 3. Calculate the required frebay volume (18-22% of total pond volume) and compare to the forebay volume provideo
Total Pond Volume 81,905 CF Value from stage -storage calculations
Required Total Forebay Volume 14,743 CF Forebay Volume= ota/ Pond Volume *18%
Provided Total Forebay Volume 16,113 CF Value from stage -storage calculations
(Provided Forebay Volume)/(Total Pond
Provided Forebay Volume:Total Pond Volume 19.7% Volume)"100%

Step 4: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
6.00
IN
Value chosen by designer
Elevation of Outlet Structure
34.90
FT
Value chosen by designer
Total Elevation Head Above Orifice
0.90
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=[(Storage
Average Elevation Head Above Orifice
0.30
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)1/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Peak Flowrate Through Low -flow Orifice
0.76
[See H droCAD Calculation]
Drawdown Time for WQV Runoff
3.02
DAYS
See H droCAD Calculation

Surf City K-8 - Wet Pond #4
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
34.00
28,320
0
0 Mermanent Pool
35.00
31,920
30,120
30,120
36.00
35,575
33,748
63,868
37.00
39,290
37,433
101,300
37.25
40,225
9,939
111,239
Stage/Storage Main Pond (Not Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
5,265
• -Sediment Storage
29.0
7,000
0
0 +Bottom Elev.
30.0
9,085
8,043
8,043
31.0
11,345
10,215
18,258
32.0
13,775
12,560
30,818
33.0
16,900
15,338
46,155
34.0
22,375
19,638
65,793 -Permanent Pool
Stage/Storage Total Pond (Including Forebay)
Main Pond
Cumulative
Volume
Forebay
Volume, S
Contour
(CF)
Volume (CF)
(CF)
28.0
-
0
29.0
0
-
0
30.0
8,043
0
8,043
31.0
18,258
2,848
21,105
32.0
30,818
6,410
37,228
33.0
46,155
10,760
56,915
34.0
65,793
16,113
81,905
Forebay 91
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
1,380
-
- -.Sediment Storage
29.0
1,905
-
-
30.0
2,510
0
0 Bottom Elev.
31.0
3,185
2,848
2,848
32.0
3,940
3,563
6,410
33.0
4,760
4,350
10,760
34.0
5,945
5,353
16,113 +forebayVolume

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Subcat Reach on Link Routing Diagram for 15348.13E WQV Pond Drawdown
Prepared by Paramounte Engineering, Inc., Printed 5/10/2016
Nvrimr ..Anne 1 n nn_11 s/n ARR77 0 9n14 HvdmrAn Snfiwarp Solutions LLC

15348.PE WQV Pond Drawdown Type ill 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HyroCAD810.00-11 s/n 08877 02014 HvdroCAD Software Solutions LLC Page 2
Summary for Pond 13P: Wet Pond #2 (Main Pond)
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.23 cfs @ 0.00 hrs, Volume= 19,833 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.23 cfs @ 0.00 hrs, Volume= 19,833 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-120.00 hrs, dt= 0.0005 hrs
Starting Elev= 34.108' Surf.Area= 19,740 sf Storage= 20,257 cf
Peak Elev= 34.108' @ 0.00 hrs Surf.Area= 19,740 sf Storage= 20,257 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert Avail.Storage Storage Description
#1 33.000' 89,843 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
33.000 16,580 0 0
34.000 19,420 18,000 18,000
35.000 22,380 20,900 38,900
36.000 25,440 23,910 62,810
37.000 28,625 27,033 89,843
Device Routing Invert Outlet Devices
#1 Primary 33.000' 3.0" Vert. Low Flow Orifice C= 0.600
Primary OutFlow Max=0.23 cfs @ 0.00 hrs HW=34.108' (Free Discharge)
L1=Low Flow Orifice (Orifice Controls 0.23 cfs @ 4.77 fps)

15348.PE WQV Pond Drawdown Type ill 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD@ 10.00-11 s/n 08877 @ 2014 HydroCAD Software Solutions LLC Page 3
0.25
0.2
0.15
3
0
u. 0.1
w e m�
Pond 13P: Wet Pond #2 (Main Pond)
Hydrograph
Time (hours)
❑ Inflow
Inflow=0.00 cfs @ 0.00 hrs
❑ Primary
Primary=0.23 cfs @ 0.00 hrs..
Peak EIev=34,108'
Storage=20,257 cf

15348.PE WQV Pond Drawdown
Prepared by Paramounte Engineering, Inc.
HydroCAD®10.00-11 s/n 08877 © 2014 HydroC/
Type ill 24-hr 1-Year Rainfaii=3. 50"
Printed 5/10/2016
Hydrograph for Pond 13P: Wet Pond #2 (Main Pond)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
0.00
0.00
20,257
34.108
0.23
2.50
0.00
18,202
34.010
0.22
5.00
0.00
16,263
33.903
0.21
7.50
0.00
14,449
33.803
0.19
10.00
0.00
12,760
33.709
0.18
12.50
0.00
11,198
33.622
0.17
15.00
0.00
9,761
33.542
0.15
17.50
0.00
8,449
33.469
0.14
20.00
0.00
7,264
33.404
0.12
22.50
0.00
6,204
33.345
0.11
25.00
0.00
5,270
33.293
0.10
27.50
0.00
4,461
33.248
0.08
30.00
0.00
3,776
33.210
0.07
32.50
0.00
3,225
33.179
0.05
35.00
0.00
2,790
33.155
0.04
37.50
0.00
2,445
33.136
0.03
40.00
0.00
2,168
33.120
0.03
42.50
0.00
1,943
33.108
0.02
45.00
0.00
1,756
33.098
0.02
47.50
0.00
1,600
33.089
0.02
50.00
0.00
1,469
33.082
0.01
52.50
0.00
1,356
33.075
0.01
55.00
0.00
1,258
33.070
0.01
57.50
0.00
1,173
33.065
0.01
60.00
0.00
1,098
33.061
0.01
62.50
0.00
1,032
33.057
0.01
65.00
0.00
973
33.054
0.01
67.50
0.00
920
33.051
0.01
70.00
0.00
873
33.048
0.01
77.50
0.00
755
33.042
0.00
80.00
0.00
722
33.040
0.00
82.50
0.00
692
33.038
0.00
85.00
0.00
665
33.037
0.00
87.50
0.00
639
33.036
0.00
90.00
0.00
615
33.034
0.00
92.50
0.00
593
33.033
0.00
95.00
0.00
573
33.032
0.00
97.50
0.00
554
33.031
0.00
100.00
0.00
536
33.030
0.00
102.50
0.00
519
33.029
0.00
105.00
0.00
503
33.028
0.00
107.50
0.00
488
33.027
0.00
110.00
0.00
474
33.026
0.00
112.50
0.00
460
33.026
0.00
115.00
0.00
448
33.025
0.00
117.50
0.00
436
33.024
0.00
120.00
0.00
425
33.024
0.00
Ve = 34.25
rp E = 33.00
3 `t o

15348.PE WQV Pond Drawdown Type /// 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 5
Summary for Pond 15P: Wet Pond #3
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.47 cfs @ 0.00 hrs, Volume= 29,614 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.47 cfs @ 0.00 hrs, Volume= 29,614 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-120.00 hrs, dt= 0.0005 hrs
Starting Elev= 31.408' Surf.Area= 22,695 sf Storage= 30,070 cf
Peak Elev= 31.408' @ 0.00 hrs Surf.Area= 22,695 sf Storage= 30,070 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert Avail.Storage Storage Description
#1 30.000' 141,713 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
30.000 19,660 0 0
31.000 21,795 20,728 20,728
32.000 24,000 22,898 43,625
33.000 26,260 25,130 68,755
34.000 28,575 27,418 96,173
35.000 30,950 29,763 125,935
35.500 32,160 15,778 141,713
Device Routing Invert Outlet Devices
#1 Primary 30.000' 4.0" Vert. Low Flow Orifice C= 0.600
Primary OutFlow Max=0.47 cfs @ 0.00 hrs HW=31.408' (Free Discharge)
t1=Low Flow Orifice (Orifice Controls 0.47 cfs @ 5.36 fps)

15348.PE WQV Pond Drawdown
Prepared by Paramounte Engineering, Inc.
HydroCAD®10.00-11 s/n 08877 © 2014 HydroC/
0.
0.4
1
1%/
1
j
1
j
1
1
0.05
Type 111 24 hr 9-Year Rainfall=3.50"
Printed 5/10/2016
LLC Paae 6
Pond 15P: Wet Pond #3
Hydrograph
-- - _ - - L
nflow
inflopv=0.00 cfs-g0.06 h-rs rimary
Primant=0.47 sfs4-0.0Q-hr9_
Paak EIOr-31;408'
Storage=30,010 -CT
1 1 20 1 41 50 61 70 81 91 100 110 120

15348.PE WQV Pond Drawdown Type /// 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 7
Hydrograph for Pond 15P: Wet Pond #3
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
0.00
0.00
30,070
31.408
0.47
2.50
0.00
26,012
31.231
0.43
5.00
0.00
22,267
31.067
0.40
7.50
0.00
18,840
30.909
0.36
10.00
0.00
15,754
30.760
0.32
12.50
0.00
13,014
30.628
0.29
15.00
0.00
10,618
30.512
0.25
17.50
0.00
8,567
30.413
0.21
20.00
0.00
6,862
30.331
0.17
22.50
0.00
5,499
30.265
0.13
25.00
0.00
4,491
30.217
0.10
27.50
0.00
3,754
30.181
0.07
30.00
0.00
3,204
30.155
0.05
32.50
0.00
2,784
30.134
0.04
35.00
0.00
2,455
30.118
0.03
37.50
0.00
2,191
30.106
0.03
40.00
0.00
1,976
30.095
0.02
42.50
0.00
1,798
30.087
0.02
45.00
0.00
1,648
30.080
0.02
47.50
0.00
1,520
30.073
0.01
50.00
0.00
1,410
30.068
0.01
52.50
0.00
1,315
30.063
0.01
55.00
0.00
1,231
30.059
0.01
57.50
0.00
1,157
30.056
0.01
60.00
0.00
1,091
30.053
0.01
62.50
0.00
1,032
30.050
0.01
65.00
0.00
979
30.047
0.01
1 70.00 0.00 888 30.043 0.00 1
75.00
0.00
812
30.039
0.00
77.50
0.00
778
30.038
0.00
80.00
0.00
747
30.036
0.00
82.50
0.00
719
30.035
0.00
85.00
0.00
692
30.033
0.00
87.50
0.00
668
30.032
0.00
90.00
0.00
645
30.031
0.00
92.50
0.00
623
30.030
0.00
95.00
0.00
603
30.029
0.00
97.50
0.00
584
30.028
0.00
100.00
0.00
567
30.027
0.00
102.50
0.00
550
30.027
0.00
105.00
0.00
534
30.026
0.00
107.50
0.00
519
30.025
0.00
110.00
0.00
505
30.024
0.00
112.50
0.00
492
30.024
0.00
115.00
0.00
479
30.023
0.00
117.50
0.00
467
30.023
0.00
120.00
0.00
456
30.022
0.00

15348.PE WQV Pond Drawdown Type /H 24 hr 9-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD810.00-11 s/n 08877 02014 HydroCAD Software Solutions LLC Page 8
Summary for Pond 16P: Wet Pond #4
Inflow = 0.00 cis @ 0.00 hrs, Volume= 0 cf
Outflow = 0.76 cfs @ 0.00 hrs, Volume= 26,539 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.76 cfs @ 0.00 hrs, Volume= 26,539 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-120.00 hrs, dt= 0.0005 hrs
Starting Elev= 34.904' Surf.Area= 31,574 sf Storage= 27,228 cf
Peak Elev= 34.904' @ 0.00 hrs Surf.Area= 31,574 sf Storage= 27,228 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert Avail.Storage Storage Description
#1 34.000' 111,239 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
34.000 28,320 0 0
35.000 31,920 30,120 30,120
36.000 35,575 33,748 63,868
37.000 39,290 37,433 101,300
37.250 40,225 9,939 111,239
Device Routing Invert Outlet Devices
#1 Primary 34.000' 6.0" Vert. Low Flow Orifice C= 0.600
rimary OutFlow Max=0.76 cis @ 0.00 hrs HW=34.904' (Free Discharge)
1=11-ow Flow Orifice (Orifice Controls 0.76 cfs @ 3.89 fps)

15348.PE WQV Pond Drawdown Type III24-hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCADO 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 9
0
0
0
U
0
3 0
0
U. 0
0
0
Pond 16P: Wet Pond #4
Hydrograph
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (hours)
❑ Inflow
❑ Primary

15348.PE WQV Pond Drawdown Type I1124 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD®10.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 10
Hydrograph for Pond 16P: Wet Pond #4
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
0.00
0.00
27,228
34.904
0.76
2.50
0.00
20,948
34.695
0.63
5.00
0.00
15,870
34.527
0.50
7.50
0.00
11,989
34.398
0.36
10.00
0.00
9,318
34.309
0.24
12.50
0.00
7,509
34.249
0.17
15.00
0.00
6,240
34.207
0.12
17.50
0.00
5.315
34.176
0.09
20.00
0.00
4,616
34.153
0.07
22.50
0.00
4,072
34.135
0.05
25.00
0.00
3,638
34.121
0.04
27.50
0.00
3,285
34.109
0.04
30.00
0.00
2,992
34.099
0.03
32.50
0.00
2,746
34.091
0.03
35.00
0.00
2,536
34.084
0.02
37.50
0.00
2,356
34.078
0.02
40.00
0.00
2,198
34.073
0.02
42.50
0.00
2,060
34.068
0.01
45.00
0.00
1,938
34.064
0.01
47.50
0.00
1,830
34.061
0.01
50.00
0.00
1,733
34.058
0.01
52.50
0.00
1,645
34.055
0.01
55.00
0.00
1,566
34.052
0.01
57.50
0.00
1,493
34.050
0.01
60.00
0.00
1,428
34.047
0.01
62.50
0.00
1,367
34.045
0.01
65.00
0.00
1,312
34.044
0.01
67.50
70.00
0.00
0.00
1,260
1.213
34.042
34.040
0.01
0.01
72.50
0.00
1169
34.039
0.00
5.
7
.
77.50
0.00
1,090
34.036
0.00
80.00
0.00
1,054
34.035
0.00
82.50
0.00
1,020
34.034
0.00
85.00
0.00
989
34.033
0.00
87.50
0.00
959
34.032
0.00
90.00
0.00
931
34.031
0.00
92.50
0.00
905
34.030
0.00
95.00
0.00
880
34.029
0.00
97.50
0.00
856
34.028
0.00
100.00
0.00
834
34.028
0.00
102.50
0.00
813
34.027
0.00
105.00
0.00
793
34:026
0.00
107.50
0.00
773
34.026
0.00
110.00
0.00
755
34.025
0.00
112.50
0.00
738
34.024
0.00
115.00
0.00
721
34.024
0.00
117.50
0.00
705
34.023
0.00
120.00
0.00
690
34.023
0.00

STORMWATER CALCULATIONS
INFILTRATION BASINS

Project Name:
Surf City K-8
Client:
LS31P
Project Number:
15348.PE
Prepared By:
DJF
Date:
5/10/16
Secondary Infiltration System Design #1
Impervious Area:
Total Impervious Area
Soils Testing Information:
Soil Type =
EL. At Test Location =
Depth to SHWL =
SHWL =
Infiltration Rate =
1/2 Infiltration Rate =
247,100 sf
Leon fine sand (LnA)
36.00
2.0 ft
34.0
3.13 in/hr
1.565 in/hr
Stormwater Quality Requirement:
Drainage Area to System =
10.82 Ac.
Impervious Area =
5.67 Ac.
% Impervious
52.45 %
Runoff Coefficent (Rv) =
0.522 in/in
Req. 1.5" Runoff Volume =
N/A cf
lyr Volume (SCS Method)
67,716 cf
Weir Elevation =
36.00 EL.
Draw Down Analysis:
........................................................................
PAR.A Mo���T�
Bottom Area of Basin 9,815 sf
Bottom Elevation of Basin 35.00 EL.
Basin Depth 1.00 ft
Draw Down Time = 2.20 days (from Darcy's Equation)
(At 1/2 Infiltration Rate)

Project Name:
Surf City K-8
Client:
LS3P
Project Number:
15348.PE
Prepared By:
DJF
Date:
5/10/16
Secondary Infiltration System Design #2
Impervious Area:
Total Impervious Area
Soils Testing Information:
Soil Type =
EL. At Test Location =
Depth to SHWL =
SHWL =
Infiltration Rate =
1/2 Infiltration Rate =
99,125 sf
Leon fine sand (LnA)
33.00
1.0 ft
32.0
2.15 in/hr
1.075 in/hr
Stormwater Quality Requirement:
Drainage Area to System =
4.83 Ac.
Impervious Area =
2.28 Ac.
% Impervious
47.12 %
Runoff Coefficent (Rv) =
0.474 in/in
Req. 1.5" Runoff Volume =
N/A cf
iyr Volume (SCS Method)
20,259 cf
Weir Elevation =
34.00 EL.
Draw Down Analysis:
I-1-1k .A:�OUNTE
I M i F Nf E t it I N a., I N,
Bottom Area of Basin 5,725 sf
Bottom Elevation of Basin 33.00 EL.
Basin Depth 1.00 ft
Draw Down Time = 1.65 days (from Darcy's Equation)
(At 1/2 Infiltration Rate)

STORMWATER CALCULATIONS
LEVEL SPREADERS

ProjectName: Surf City K-8.................................................................... .......................................................
Client: LS3P D A
I-1-ILRAMOUNITE
Project Number: 15348.PE
Prepared By: DJF
Date: 5/10/16
Secondary 'Effective Infiltration System' Design - LS-VFS *3
Soils Testing Information:
Soil Type = Leon Fine Sand (LnA)
EL. At Test Location = 30.50
Depth to SHWL = 0.83 ft
SHWL = 29.67
"Effective Infiltration Rate" = 0.52 in/hr (Assumed minimum to calculate VFS)
Stormwater Quality Requirement:
lyr Volume (SCS Method) 30,064 cf
Draw Down Analysis:
Area of VFS =
6,000 sf
Length of VFS =
100 ft
Width of VFS =
60 ft
Draw Down Time =
4.82 days (from Darcy's Equation)
HydroCAD 10-YR Flow Analysis:
10-YR Q =
8.88 cfs
Req'd LS Length =
89 ft (Per BMP Manual - 10 Ft / 1 cfs)
Provided LS Length =
100 ft

15348.PE SWM POST
Prepared by Paramounte Engineering, Inc.
HydroCAD®10.00-11 s/n 08877 © 2014 Hydro
Type III 24-hr 10-Year Rainfall=6. 99"
Printed 5/10/2016
Summary for Pond 15P: Wet Pond #3
Inflow Area = 431,418 sf, 35.46% Impervious, Inflow Depth = 4.69" for 10-Year event
Inflow =
55.95 cfs @
12.07 hrs, Volume=
168,441 cf
Outflow =
8.88 cfs @
12.55 hrs, Volume=
166,101 cf, Atten= 84%, Lag= 28.6 min
Primary =
8.88 cfs @
12.55 hrs, Volume=
166,101 cf
Secondary =
0.00 cis @
0.00 hrs, Volume=
0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 33.44' @ 12.55 hrs Surf.Area= 27,281 sf Storage= 80,850 cf
Plug -Flow detention time= 329.5 min calculated for 166,101 cf (99% of inflow)
Center -of -Mass det. time= 321.0 min ( 1,128.1 - 807.1 )
Volume Invert
Avail.Storage Storage Description
#1 30.00'
141,713 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
30.00
19,660
0 0
31.00
21,795
20,728 20,728
32.00
24,000
22,898 43,625
33.00
26,260
25,130 68,755
34.00
28,575
27,418 96,173
35.00
30,950
29,763 125,935
35.50
32,160
15,778 141,713
Device Routing
Invert
Outlet Devices
#1 Primary
30.00'
15.0" Round Culvert
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 30.00' / 30.00' S= 0.0000 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1
30.00'
4.0" Vert. Low Flow Orifice C= 0.600
#3 Device 1
31.50'
36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 33.75' Emergency Spillway, C= 2.60
Offset (feet) 0.00 4.50 64.50 69.00
Height (feet) 1.50 0.00 0.00 1.50
rimary OutFlow Max=8.88 cfs @ 12.55 hrs HW=33.44' TW=0.00' (Dynamic Tailwater)
rCulvert (Barrel Controls 8.88 cfs @ 7.24 fps)
2=Low Flow Orifice (Passes < 0.76 cfs potential flow)
3 Top of Box (Passes < 60.38 cfs potential flow)
econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=30.00' TW=0.00' (Dynamic Tailwater)
=Emergency Spillway ( Controls 0.00 cfs)

15348.PE SWM POST Type /I/ 24-hr 10-Year Rainfall=6.99"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 67
R
40_
v
0 30 i.
20
10 l
Pond 15P: Wet Pond #3
Hydrograph
Inflow Area=431,418 sf
Inflow=55.95 cfs @ 12.07 hrs
Outflow=8.88 cfs @ 12.55 hrs
Primary=8.88 cfs @ 12.55 hrs
Secondary=0.00 cfs @ 0.00 hrs
Peak Elev=33.44'
Storage=80,850 cf
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)
❑ Inflow
❑ Outflow
❑ Primary
❑ Secondary

Project Name: Surf City K-8 ..._._..._......... . __................
Client: LS3P A.LVI. �-i
Project Number: 15348.PE N , ,,, R "-'
Prepared By: DJF
Date: 5/10116
Secondary 'Effective Infiltration System' Design - LS-VFS #4
Soils Testing Information:
Soil Type = Mandarin Fine Sand (Ma) / Murville Muck (Mu)
EL. At Test Location = 34.00
Depth to SHWL = 0.83 ft
SHWL = 33.17
"Effective Infiltration Rate" = 0.52 in/hr (Assumed minimum to calculate VFS)
Stormwater Quality Requirement:
lyr Volume (SCS Method) 27,227 cf
Draw Down Analysis:
Area of VFS
5,250 sf
Length of VFS =
70.00 ft
Width of VFS =
75.00 ft
Draw Down Time =
4.99 days (from Darcy's Equation)
HydroCAD 10-YR Flow Analysis:
10-YR Q =
5.76 cfs
Req'd LS Length =
58 ft (Per BMP Manual - 10 Ft / 1 cfs)
Provided LS Length =
70 ft

15348.PE SWM POST Type Ill 24-hr 10-Year Rainfall=6.99"
Prepared by Paramounte Engineering, Inc. Printed 5/10/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 68
Summary for Pond 17P: Wet Pond #4
Inflow Area = 196,630 sf, 61.01 % Impervious, Inflow Depth = 5.93" for 10-Year event
Inflow = 30.48 cfs @ 12.07 hrs, Volume= 97,150 cf
Outflow = 5.76 cfs @ 12.50 hrs, Volume= 94,653 cf, Atten= 81 %, Lag= 25.7 min
Primary = 5.76 cfs @ 12.50 hrs, Volume= 94,653 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 35.57' @ 12.50 hrs Surf.Area= 34,020 sf Storage= 49,509 cf
Plug -Flow detention time= 364.4 min calculated for 94,653 cf (97% of inflow)
Center -of -Mass det. time= 348.6 min ( 1,124.1 - 775.5 )
Volume Invert Avail.Storage Storage Description
#1 34.00' 111,239 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
34.00 28,320 0 0
35.00 31,920 30,120 30,120
36.00 35,575 33,748 63,868
37.00 39,290 37,433 101,300
37.25 40,225 9,939 111,239
Device Routing Invert Outlet Devices
#1 Primary 34.00' 23.0" W x 14.0" H, R=22.0" Elliptical RCP _Elliptical 23x14
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 34.00' / 34.00' S= 0.0000 '/' Cc= 0.900
n= 0.013, Flow Area= 1.83 sf
#2 Device 1 34.00' 6.0" Vert. Low Flow Orifice C= 0.600
#3 Device 1 35.00' 3.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 35.95' Emergency Spillway, C= 2.60
Offset (feet) 0.00 3.90 103.90 107.80
Height (feet) 1.30 0.00 0.00 1.30
Primary OutFlow Max=5.76 cfs @ 12.50 hrs HW=35.57' TW=0.00' (Dynamic Tailwater)
L1=RCP_Elliptical 23x14 (Barrel Controls 5.76 cfs @ 3.15 fps)
N=Low Flow Orifice (Passes < 1.09 cfs potential flow)
=Top of Box (Passes < 17.09 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=34.00' TW=0.00' (Dynamic Tailwater)
4=Emergency Spillway ( Controls 0.00 cfs)

15348.PE SWM POST
Prepared by Paramounte Engin
HvdroCAD® 10.00-11 s/n 08877
30
25
20
-
o
15
LL
10
-
5
'
Type Ill 24-hr 10-Year Rainfall=6.99"
Inc. Printed 5/10/2016
droCAD Software Solutions LLC Page 69
Pond 17P: Wet Pond #4
Hydrograph
❑ inflow
Inflow Area 196.630 sf
El Outflow
Inflow=3Q.48 cfs @ 12.Q7 hr§
❑ Primary
outflow=s76 cfs-@ tZ.gO hror
❑ Seconds
Secondary
Primary=5.76 efs Q 12.90 hn$
Second-arjff0,Q0 ckq_ .QO hrs
Peak Elev-35.57P
Storage=49,509 of
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Time (hours)

SOILS REPORT (BY OTHERS)

4 ^�
E CARQL II�A LLP "Setting the Standard for ,3erYfic& "
r �r Geotecl!rrk--al • Constru,r. ion Materials W Envirorimpntal d `racilit:i s
February 22, 2016
Mr. Justin Whitley
Barnhill Contraction Company
P.O. Box 31765
Raleigh, North Carolina 27622
Reference: Report of Seasonal High Water Table Estimation and Infiltration Testing
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
Dear Mr. Whitley:
ECS Carolinas, LLP (ECS) recently conducted a seasonal high water table (SHWT) estimation
and infiltration testing within proposed stormwater best management practice (BMP) areas at
the proposed Surf City K-8 site off of Perkins Drive in Hampstead, Pender County, North
Carolina. This letter, with attachments, is the report of our testing.
Field Testing
On February 2, 2016, ECS conducted an exploration of the subsurface soil and groundwater
conditions at seven requested locations (1-1 through 1-7) shown on the attached Test Location
Plan (Figure 1). On February 19, 2016, ECS returned to the site to assess a requested three
additional borings (1-8 through 1-10). ECS determined the boring locations using a site plan
provided by Paramounte Engineering. The purpose of this exploration was to obtain subsurface
information of the in situ soils for the stormwater BMP areas. ECS explored the subsurface soil
and groundwater conditions by advancing one hand auger boring into the existing ground
surface at the requested boring locations. ECS visually classified the subsurface soils and
obtained representative samples of each soil type encountered. ECS also recorded the SHWT
and groundwater elevation observed at the time of the hand auger borings. The attached
Infiltration Testing Form provides a summary of the subsurface conditions encountered at the
hand auger boring locations.
The SHWT and groundwater elevation was estimated at the boring locations below the existing
grade elevation. A summary of the findings are as follows:
Location
SHWT
Groundwater
1-1
24 inches
30 inches
1-2
25 inches
36 inches
1-3
0 inches
8 inches
1-4
12 inches
24 inches
1-5
18 inches
42 inches
1-6
6 inches
16 inches
1-7
10 inches
24 inches
1-8
4 inches
15 inches
1-9
10 inches
24 inches
1-10
12 inches
30 inches
I.. • t: 5 %enlral, Y'..L! • E , Florida. UG • �;C;s Rfiid-Ailan;iC'. 1,!., • tC M.&Wav V.0 • "r_CS 11 r . EC �D harm L1."
vv,.VN ecs2t,mi(ed com

Report of SHWT Estimation and infiltration Testing
Surf City K-8 Site
Hampstead, Pander County, North Carolina
ECS Project No. 49.1386
February 22, 2016
ECS has conducted ten infiltration tests utilizing a compact constant head permeameter near
the hand auger borings in order to estimate the infiltration rate for the subsurface soils.
Infiltration tests are typically conducted at two feet above the SHWT or in the most restrictive
soil horizon. Tests in clayey conditions are conducted and calculated up to 30 minute intervals.
If an exact hydraulic conductivity is necessary for these locations, then ECS recommends
collecting samples by advancing Shelby tubes and performing laboratory permeability testing.
Field Test Results
Below is a summary of the infiltration test results:
Location
Description
Depth
Inches/
hour
1-1
Black fine SAND w/ silt
16 inches
3.13
1-2
Black fine SAND w/ silt
18 inches
1.48
1-3
Black silty SAND
10 inches
<.001
1-4
Gray fine SAND w/silt
10 inches
2.15
1-5
Black silty SAND
20 inches
0.032
1-6
Black silty SAND
10 inches
<.001
1-7
Black silty SAND
10 inches
0.029
1-8
Gray fine SAND
10 inches
0.017
1-9
Black silty SAND
10 inches
0.012
1-10
Black silty SAND
18 inches
0.024
Infiltration rates and SHWT may vary within the proposed site due to changes in elevation and
subsurface conditions. The moisture content associated with the shallow groundwater
elevations observed on this site influenced the hydraulic conductivity results.
2

Report of SHWT Estimation and Infiltration Testing
Sun` City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Closure
ECS's analysis of the site has been based on our understanding of the site, the project
information provided to us, and the data obtained during our exploration. If the project
information provided to us is changed, please contact us so that our recommendations can be
reviewed and appropriate revisions provided, if necessary. The discovery of any site or
subsurface conditions during construction which deviate from the data outlined in this
exploration should be reported to us for our review, analysis and revision of our
recommendations, if necessary. The assessment of site environmental conditions for the
presence of pollutants in the soil and groundwater of the site is beyond the scope of this
geotechnical exploration.
ECS appreciates the opportunity to provide our services to you on this project. If you have any
questions concerning this report or this project, please contact us at [phone].
Respectfully,
ECS CAROLINAS, LLP
K. Brooks Wall
Project Manager
bwall(aD-ecslimited.com
910-686-9114
Attachments: Figure 1 - Test Location Plan
Infiltration Testing Form
ASFE Document
W. Brandon Fulton, PSC, PWS, LSS
Environmental Department Manager
bfulton(aD-ecslimited.com
704-525-5152
3

® APPROXIMATE BORING LOCATIONS
SCALE SHOWN ABOVE
J
Surf City K-8 Site
Hampstead, Ponder County,
North Carolina
ECS Project # 49.1386
ebruary 2nd and 19t', 2016
KBW
N
W E
Figure 1- Boring Location Plan
Provided by: Ooogle Maps and
Paramounte Engineering

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS .Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-1 0-12" SP Gray fine SAND
125'-16" SM Black fine SAND w/silt
16"-36" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 24 inches below the
existing grade elevation.
Groundwater was encountered at 30 inches below the existing grade
elevation.
Test was conducted at 16 inches below existing grade elevation
Infiltration Rate: 3.13 per hour
Location Depth USCS
1-2 0-3"
SM
3"-10"
SP
10"-20"
SM
20"-30"
SP
Soil Description
Black silty SAND
Gray fine SAND
Black fine SAND w/silt
Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 25 inches below the
existing grade elevation.
Groundwater was encountered at 36 inches below the existing grade
elevation.
Test was conducted at 18 inches below existing grade elevation
Infiltration Rate: 1.48 per hour
Location Depth USCS Soil Description
1-3 0-4" SM Black silty SAND
4"-12" SP Gray fine to med. SAND
Seasonal High Water Table was estimated to be at 0 inches below the
existing grade elevation.
Groundwater was encountered at 8 inches below the existing grade
elevation
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: <0.001 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS
1-4 0-101, SM
10"-24" SP
Soil Description
Gray fine SAND w/silt
Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 12 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 2.15 per hour
Location Depth USCS Soil Description
1-5 0-16" SP White fine SAND
16"-30" SM Black silty SAND
30"-48" SP Tan/orange/gray fine SAND w/clay
Seasonal High Water Table was estimated to be at 18 inches below the
existing grade elevation.
Groundwater was encountered at 42 inches below the existing grade
elevation.
Test was conducted at 20 inches below existing grade elevation
Infiltration Rate: 0.032 per hour
Location Depth USCS Soil Description
1-6 0-101, SM Black silty SAND
10"-24" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 6 inches below the
existing grade elevation.
Groundwater was encountered at 16 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: <0.001 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-7 0-101, SM Gray fine SAND w/silt
10$5-24" SM Black silty SAND
24"-36" SP Gray fine SAND
Seasonal High Water Table was estimated to be at 10 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.029 per hour
Location Depth USCS Soil Description
1-8 0-6" SM Black silty SAND
6"-24" SP Gray fine SAND
Seasonal High Water Table was estimated to be at 4 inches below the
existing grade elevation.
Groundwater was encountered at 15 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.017 per hour
Location Depth USCS Soil Description
1-9 0-10" SP Gray fine SAND
10"-14" SM Black silty SAND
14"-24" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 10 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.012 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-10 0-12" SP Gray fine SAND
12"-22" SM Black silty SAND
22"-30" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 12 inches below the
existing grade elevation.
Groundwater was encountered at 30 inches below the existing grade
elevation.
Test was conducted at 18 inches below existing grade elevation
Infiltration Rate: 0.024 per hour

r- Geolechnicel Engineeping Report ---)
Geotechnical Services Are Performed for
Specific Purposes, Persons, and Projects
Geotechnical engineers structure their services to meet the specific needs of
their clients. A geotechnical engineering study conducted for a civil engineer
may not fulfill the needs of a construction contractor or even another civil
engineer. Because each geotechnical engineering study is unique, each geo-
technical engineering report is unique, prepared solelyfor the client. No one
except you should rely on your geotechnical engineering report without first
conferring with the geotechnical engineer who prepared it. And no one - not
even you - should apply the report for any purpose or project except the one
originally contemplated.
Read the Full Resort
Serious problems have occurred because those relying on a geotechnical
engineering report did not read it all. Do not rely on an executive summary.
Do not read selected elements only.
A Geotechnical Engineering Report Is Based an
A Unique Set of Project -Specific Factors
Geotechnical engineers consider a number of unique, project -specific factors
when establishing the scope of a study. Typical factors include: the client's
goals, objectives, and risk management preferences; the general nature of the
structure involved, its size, and configuration; the location of the structure
on the site; and other planned or existing site improvements, such as access
roads, parking lots, and underground utilities. Unless the geotechnical engi-
neer who conducted the study specifically indicates otherwise, do not rely on
a geotechnical engineering report that was:
• not prepared for you,
not prepared for your project,
not prepared for the specific site explored, or
completed before important project changes were made.
Typical changes that can erode the reliability of an existing geotechnical
engineering report include those that affect:
• the function of the proposed structure, as when it's changed from a
parking garage to an office building, or from alight industrial plant
to a refrigerated warehouse,
elevation, configuration, location, orientation, or weight of the
proposed structure,
composition of the design team, or
project ownership.
As a general rule, always inform your geotechnical engineer of project
changes - even minor ones - and request an assessment of their impact.
Geolechnical engineers cannot accept responsibility or liability for problems
that occur because their reports do not consider developments of which they
were not informed.
Subsurface Conditions Can Change
A geotechnical engineering report is based on conditions that existed at the
time the study was performed. Do not rely on a geotechnical engineering
reportwhose adequacy may have been affected by: the passage of time; by
man-made events, such as construction on or adjacent to the site; or by natu-
ral events, such as floods, earthquakes, or groundwater fluctuations. Always
contact the geotechnical engineer before applying the report to determine if it
is still reliable. A minor amount of additional testing or analysis could prevent
major problems.
Most Geotechnical findings Are Professional
Opinions
Site exploration identifies subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. Geotechnical engineers
review field and laboratory data and then apply their professional judgment
to render an opinion about subsurface conditions throughout the site. Actual
subsurface conditions may differ -sometimes significantly from those indi-
cated in your report. Retaining the geotechnical engineer who developed your
report to provide construction observation is the most effective method of
managing the risks associated with unanticipated conditions.
A Reports Recommendations Are Of Final
Do not overrely on the construction recommendations included in your re-
port. Those recommendations are not final, because geotechnical engineers
develop them principally from judgment and opinion. Geotechnical engineers
can finalize their recommendations only by observing actual

subsurface conditions revealed during construction. The geotechnical engi-
neer who developed your report cannot assume responsibility or liability for
the report's recommendations if that engineer does not perform construction
observation.
A Geotechnical Engineering Report Is Subject to
Misinterpretation
Other design team members' misinterpretation of geotechnical engineer-
ing reports has resulted in costly problems. Lower that risk by having your
geotechnical engineer confer with appropriate members of the design team
after submitting the report. Also retain your geotechnical engineer to review
pertinent elements of the design team's plans and specifications. Contractors
can also misinterpret a geotechnical engineering report. Reduce that risk by
having your geotechnical engineer participate in prebid and preconstruction
conferences, and by providing construction observation.
Do Not Redraw the Engineer's Logs
Geotechnical engineers prepare final boring and testing logs based upon
their interpretation of field logs and laboratory data. To prevent errors or
omissions, the logs included in a geotechnical engineering report should
never be redrawn for inclusion in architectural or other design drawings.
Only photographic or electronic reproduction is acceptable, but recognize
that separating logs from the report can elevate risk.
Give Contractors a Complete Report and
Guidance
Some owners and design professionals mistakenly believe they can 111aKe
contractors liable for unanticipated subsurface conditions by limiting what
they provide for bid preparation. To help prevent costly problems, give con-
tractors the complete geotechnical engineering report, butpreface it with a
clearly written letter of transmittal. In that letter, advise contractors that the
report was not prepared for purposes of bid development and that the report's
accuracy is limited; encourage them to confer with the geotechnical engineer
who prepared the report (a modest fee may be required) and/or to conduct ad-
ditional study to obtain the specific types of information they need or prefer.
A prebid conference can also be valuable. Be sure contractors have sufficient
time to perform additional study. Only then might you be in a position to give
contractors the best information available to you, while requiring them to at
least share some of the financial responsibilities stemming from unantici-
pated conditions.
Read Responsibility Provisions Closely
Some clients, design professionals, and contractors do not recognize that
geotechnical engineering is far less exact than other engineering disciplines.
This lack of understanding has created unrealistic expectations that have led
to disappointments, claims, and disputes. To help reduce the risk of such
outcomes, geotechnical engineers commonly include a variety of explanatory
provisions in their reports. Sometimes labeled "limitations" many of these
provisions indicate where geotechnical engineers' responsibilities begin
and end, to help others recognize their own responsibilities and risks. Read
these provisions closely. Ask questions. Your geotechnical engineer should
respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The equipment, techniques, and personnel used to perform a geoenviron-
mental study differ significantly from those used to perform a geotechnical
study. For that reason, a geotechnical engineering report does not usually re-
late any geoenvironmental findings, conclusions, or recommendations; e.g.,
about the likelihood of encountering underground storage tanks or regulated
contaminants. Unanticipated environmental problems have led to numerous
project failures. If you have not yet obtained your own geoenvironmental in-
formation, ask your geotechnical consultant for risk management guidance.
Do not rely on an environmental report prepared for someone else.
Obtain Professional Assistance To Deal with Mold
Diverse strategies can be applied during building design, construction, op-
eration, and maintenance to prevent significant amounts of mold from grow-
ing on indoor surfaces. To be effective, all such strategies should be devised
for the express purpose of mold prevention, integrated into a comprehensive
plan, and executed with diligent oversight by a professional mold prevention
consultant. Because just a small amount of water or moisture can lead to
the development of severe mold infestations, a number of mold prevention
strategies focus on keeping building surfaces dry. While groundwater, wa-
ter infiltration, and similar issues may have been addressed as part of the
geotechnical engineering study whose findings are conveyed in -this report,
the geotechnical engineer in charge of this project is not a mold prevention
consultant; me -of Me services performed in cwmwcMw with
the geotecb" engineer's study were deslgmrd or conducted
for the pmpese of mold prevendm. Proper bal0me bum of
the reconm mbu ms cm►veyed U Uft report wig not of itself
he sulllchmt to prevent mold Mom growft In or on the sMnc-
ture iNvow.
Rely on Your ASFE-Member Geotechnical
Engineer For Additional Assistance
Membership in ASFE/The Best People on Earth exposes geotechnical engi-
neers to a wide array of risk management techniques that can be of genuine
benefit for everyone involved with a construction project. Confer with your
ASFE-member geotechnical engineer for more information.
ASFE
The Bost People so Earth
8811 Colesville Road/Suite G106, Silver Spring, MD 20910
Telephone:' 301/565-2733 Facsimile: 301/589-2017
e-mail: [e-mail] www.aste.org
Copyright 2004 by ASFE, Inc. Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with ASM specific
written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of ASFE, and only for purposes
of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report Any other firm,
individual, or other entity that so uses this document without being anASFE member could be committing negligent or intentional (fraudulent) misrepresentation.
IIGER06045.0M

Lewis,Linda
From:
Lewis,Linda
Sent:
Monday, May 09, 2016 11:15 AM
To:
Robert Balland; Dan Fisk ([e-mail])
Cc:
Scott, Georgette; Lucas, Annette ([e-mail]);
'[e-mail]2.i �c.us'
Subject:
FW: Surf City K-8 SW8 160410
Attachments:
TRW SCS Method 03-07-14.pdf
Thanks for your patience on the TR-55 question. I was able to speak with Annette this morning, and
was told that -the use of TR-55 and a composited curve number would be fine and would not be
considered alternative design, which keeps the project in the Express program. The SCS method
became an acceptable runoff calculation methodology in March 2014, but, as that guidance pointed
out, only the Discrete Curve Number method could be used. (None of the Regional Office stormwater
staff had been made aware of the ability to now disregard the Discrete Curve plumber method and
allow a composited curve number.
So, please submit your new design calculations ASAP to maintain the express review timelines,
based on the use of a wet pond (I year 24 hour pre/post), drawn down in 2-5 days via a purnp, to a
secondary BMP which has been designed to meet the no -discharge requirement, which in this case
will be a vegetated filter designed to effectively infiltrate the design storm. My previous advice
regarding the design of the VFS to meet effective infiltration can be taken or left; as you see fit.
Linda
From: Lewis,Linda
Sent: Friday, May 06, 2016 4:33 PM
To: Robert Balland <[e-mail]>; Dan Fisk ([e-mail]) <dfisk@paramounte-
eng.com>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: FW: Surf City K-8 SW8160410
Rob & Dan:
Annette was out of the office this entire past week, so I left a voice message for her with my question
and a request for her to call me on Monday.
Thanks for your patience.
Linda
From: Lewis,Linda
Sent: Friday, May 06, 2016 3:19 PM
To:'Dan Fisk' <[e-mail]>; Robert Balland <[e-mail]>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8 SW8160410
found it. Thank you so much for making sure, though.

minute durations) were computed using an average ratio between the n-minute and 60-minute
quantiles due to the small number of stations recording data at less than 60-minute intervals.
For the first time, the National Weather Service is providing confidence limits for the precipitation
frequency estimates in the area covered by NOAA Atlas 14. Monte Carlo Simulation was used to -
produce upper and lower bounds at the 90% confidence level.
In the regional approach, the second and higher order moments are constant for each region
resulting in a potential for discontinuities in the quantiles at regional boundaries. In order to avoid
potential discontinuities and to achieve an effective spatial interpolation of quantiles between
observing stations, the data series means at each station for each duration were spatially interpolated
using PRISM technology by the Spatial Climate Analysis Service (SCAS) at Oregon State University
(Appendix A.4). Because the mean was derived directly at each observing station from the data series
and independently of the regional computations, it was not subject to the same discontinuities. The
grid of quantiles for each successive average recurrence interval was then derived in an iterative
process using a strong linear relationship between a particular duration and average recurrence interval
and the next rarer average recurrence interval of the same duration (see Section 4.8.2). The resulting
set of grids were tested and adjusted in cases where inconsistencies occurred between durations and
frequencies. Computations were made over a geographic domain that was larger than the published
domain to ensure continuity at the edges of the published domain.
Both the spatial interpolation and the point estimates were subject to external peer reviews (see
Section 6 and Appendix A.5). Based on the results of the peer review, adjustments were made where
necessary by the addition of new observations or removal of questionable ones. Adjustments were
also made in the definition of regions.
Temporal precipitation patterns were extracted for use with the precipitation frequency estimates
presented in the Atlas (Appendix A.1). The temporal patterns are presented in probabilistic terms and
can be used in Monte Carlo development of ensembles of possible scenarios. They were specifically
designed to be consistent with the definition of duration used for the precipitation frequency estimates.
The seasonality of heavy precipitation is represented in seasonal exceedance graphs that are
available through the Precipitation Frequency Data Server. The graphs were developed for each
region by tabulating the number of events exceeding the precipitation frequency estimate at each
station for a given annual exceedance probability (Appendix A.2).
The 1-day annual maximum series were analyzed for linear trends in mean and variance and shifts
in mean to determine whether climate change during the period of record was an issue in the
production of this Atlas (Appendix A.3). The results showed little observable or geographically
consistent impact of climate change on the annual maximum series during the period of record and so
the entire period of record was used. The estimates presented in this Atlas make the necessary
assumption that there is no effect of climate change in future years on precipitation frequency
estimates. The estimates will need to be modified if that assumption proves quantifiably incorrect.
hiO3AA A i.is 14 ?del iirt 2 Versicril 4.0

Scott, Georgette
From:
Dan Fisk <[e-mail]>
Sent:
Friday, May 06, 2016 11:20 AM
To:
Lewis,Linda; Robert Balland
Cc:
Scott, Georgette; Weaver, Cameron
Subject:
RE: Surf Citv K-8 SW8 160410
Linda
Thank you for the update and reference for the Technical Review Workgroup — it can be very difficult to locate all the
changes/updates.
After reading through the Technical Review Workgroup documents, I believe there could be a better option (3rd Option)
for this site to meet all requirements and was hoping you could confirm I am understanding this correctly. Within the
"Options for Complying with the No Direct Discharge to SA Waters Provision of the Coastal Stormwater Rule" Option
3.B. — I am interpreting this to mean that the four 90% TSS Wet Ponds can be discharged to a LS-VFS designed per the
BMP Manual (10-Year Storm Flow less than or equal to 10 CFS and the ponds Bypass/spillway discharging the flow
beyond the 10 CFS). This could allow for the removal of all infiltration basins and pumps as long as a LS-VFS was
provided for each Wet Pond?
regards to the NOAA Rainfall Depth, I would be happy to have further discussions and will do so in the future;
however, in the interest of time I will revise the calculations to be based off the 3.72 inch depth even though it is still my
I and understanding that a depth selected within the 90% confidence interval range is supported through the
OAA calculations. In revising the depth to match 3.72, it is my understanding that under Session Law 2015-286 143-
14.7.62.1 the TR-55 SCS Method (not the discrete SCS method nor the Simple Method) can be used in calculating the 1-
ear 24-hour storm volume difference and plan on providing calculations in that manner if your understanding is the
1
Thank you again,
Daniel J. Fisk, PE
PARAMOUNTE ENGINEERING, INC.
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
910-791-6707 (P)
910-791-6760 (F)
[e-mail]
www.paramounte-eng.com
From: Lewis,Linda [mailto:[e-mail]]
Sent: Thursday, May 05, 2016 6:01 PM
To: Dan Fisk <[e-mail]>; Robert Balland <[e-mail]>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8 SW8160410
Thanks so much for the information Dan. I will proceed with the review on the basis of a wet pond
with a pump as the drawdown device and infiltration as the secondary BMP. As per the Technical
Review Workgroup guidance approved on March 7, 2014, the use of a 90% wet pond that provides
storage for the pre/post 1 year 24 hour storm volume difference and discharges that volume to a
secondary BMP will meet the "effective infiltration" requirement for SA waters without the need to

have a separate vegetated filter or level spreader for the overflow. Any release of stormwater from the
secondary BMP would be at a non -erosive velocity at the edge of the buffer, or into wetlands that do
not have a direct conveyance to SA waters. As it would apply to the Surf City K-8 project, the pump
would be the orifice, and it's pump rate under TDH should be set to drawdown that 1 year 24 hour
pre/post volume within 2-5 days and discharge that volume to the secondary BMP to be infiltrated. If
the wetlands do not contain a conveyance to SA waters, and if the emergency overflow in the
infiltration basin is engaged, that runoff would need to be controlled to discharge at a non -erosive
'velocity into the wetlands. You would need to provide revised plans, application documents,
supplements, O&M's and calculations for this design that.doesn't include any "2 times" or "2.5 times"
the design volume.
I am still concerned about the NOAA number and I'd like to understand how this works for future
projects, so I'm going to ask a lot of questions - I hope that is OK. I remember reading the narrative
about the fact that the selected depth fell within the 90% confidence interval, but I did not interpret
that to mean you picked a value that was lower than the mean reported on the Precipitation
Frequency table by NOAA. I thought you were just being thorough in your narrative.
How does one determine which value in that range of values to choose? Other than for the obvious
reason of sizing BMP's for less volume, why did you choose a value on the low side of the range
instead of on the higher side of the range? Is the use of 3.5" a mathematically derived choice, or an
"eenie-meenie-minie-moe" choice? What are the determining factors that go into choosing a particular
value in that 90% confidence range? Why did you not choose 4.0"? 1 would have reasoned that in the
absence of rain gauge data specific for your site, the mean value for the gauge location closest to the
site would be a conservative choice. Do you have specific rain gauge data for this site to support the
use of 3.5" vs. 4"? Are you saying that the distance from the site to the recording gauge location
is justification for choosing a lower number? Why is it not justification for choosing a higher number?
NOAA makes certain assumptions and/or follows certain mathematical formulas to extrapolate
precipitation depths for sites that are distant from the gauge site. What assumptions and formulas did
you use to arrive at the conclusion that a value of 3.5" was right for this site? I thought the point of
being able to enter lat and long into the NOAA site was to get a relatively accurate precipitation
frequency and depth estimate for that specific location based on extrapolated data derived by
accepted mathematical formulas and assumptions by NOAA.
Their Atlas 14 publication for North Carolina is definitely a snoozer — they use way too many big
words. I've only been able to read a few pages. If I find anything of use in there, I'll let you know.
Thanks for your time on this.
Linda
From: Dan Fisk [mailto:[e-mail]]
Sent: Thursday, May 05, 2016 3:56 PM
To: Lewis,Linda <[e-mail]>; Robert Balland <[e-mail]>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8 SW8 160410
Linda
Thank you for your email and additional information so we can clarify the intent of the design. You are correct in that
the current design took into account for the pumped infiltration basin language as well as the typical infiltration basin
language resulting in the "2 times" or "2.5 times" the volume depending on the option as you mentioned. To further

clarify; it is true that the 90% TSS Wet Ponds receive and treat all proposed impervious surface runoff from the Site as
the Primary BMP with the Infiltration Basins being secondary treatment for the Wet Ponds required and provided water
quality volume (WQV) which is received either by gravity/pipe (Wet Pond #1 and #2) or through a pump (Wet Pond #3
and #4) as mentioned. Furthermore, any storm runoff beyond the required and provided WQV would be discharged by
way of the Wet Ponds spillway/outlet structure through the Site's current drainage patterns (wetlands).
We would obviously prefer to have the site be designed with the 90% TSS removal as the primary BK4Ps and the
infiltration basins acting as secondary BMPs to treat the Wet Ponds WQV discharge and remove any multiples of the
required WQV storage that has been implemented in the current calculations if a LS/VFS will not be required due to this
set up? I'm assuming I need to get you revised calculations (and anything else that gets revised due to the change) that
remove the muitipie applied to the WQV?
As for the NOAA precipitation depth selected, I did not hide the manner in which I arrived at a 3.5 inch depth for the
Site, and it was not my intent to give the impression that I was changing any data. As referenced in the Narrative under
the Design Method section, the rainfall depth selected was taken from the NOAA Atlas 14 PFDS 90% confidence interval
(the smaller numbers that give a range in parenthesis in the chart). As we all know, the NOAA depths are derived and
updated on a continual basis from Data received at multiple gauges; however, these gauges can be located far away
from a specific site and therefore rely on mathematical assumptions to get to the bold number in the chart that you
referenced. Due to those assumptions, the standard deviation or 90% confidence interval is derived and provided in the
chart. Furthermore, counties and municipalities that have implemented stormwater management ordinances with
specified rainfall depths to be used for incremental storms will rarely match the bold number from a site specific NOAA
Atlas 14 table; however, the majority of the specified rainfall depths from those ordinances will fall within the 90%
confidence interval. Therefore, I believe that selecting a rainfall depth within the 90% confidence interval meets the
intent of the broader, multiple year span of what the 1-year 24-hour site specific rainfall depth could be.
Thank you,
Daniel J. Fisk, PE
PARAMOUNTE ENGINEERING, INC.
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
910-791-6707 (P)
910-791-6760 (F)
[e-mail]
www.paramounte-eng.com
From: Lewis,Linda [mailto:[e-mail]]
Sent: Wednesday, May 04, 2016 6:07 PM
To: Robert Balland <[e-mail]>; Dan Fisk <[e-mail]>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: Surf City K-8 SW8160410
Hey Rob and Dan:
Before I get too deep into this Express review, I need for you to help me understand exactly what
option we are permitting for this site so I can tailor the rest of my review comments to that option.
During our meeting, I thought you told me that the infiltration basins were the secondary BMP's for
the wet ponds, but you've designed the ponds for "2 times" the design storm volume, so I am not sure
now. You may be mixing up the design requirements for a wet pond within Y2 mile of SA waters and
pumped infiltration, which is understandable given the many design options we have today.

Because of the proximity to SA waters, the design storm is the 1 year 24 hour storm. When I print out
the NOAA precipitation depth chart using the same latitude and longitude you did, the 1 year 24 hour
depth is shown as 3.72 inches, but the form you provided with the calculations appears to have been
manually changed to 3.5 inches. Under what authority were you allowed to change the NOAA data?
Please use the 3.72 inch precipitation depth and submit new calculations. This results in additional
minimum storage volume requirements.
The wet ponds were designed to have storage for "2 times" the design storm. However, I'm not sure
that we can apply the infiltration basin volume options in Section 16.3.9 of the BMP Manual to wet
pond design. Please note that if you design the infiltration basin to hold only "2 times" the design
storm volume, you will only get to eliminate either the bypass or the VFS, but not both. To eliminate
both, Option 3 of the manual requires either active storage volume for "2.5 times" the design storm, or
(Option 4) demonstrate that the basin can infiltrate the 10 year 24 hour storm event without
discharging at'/ of the reported infiltration rate.
I think there are 2 design options here for your consideration:
Wet Pond: If you choose to design as a "Wet Pond", you don't need to design the pond to hold "2.5
times" the volume. The 2008 rules allow the use of a wet pond within Y2 mile of SA waters if the
storage volume is the greater of 1.5" or the pre/post volume for the 1 year 24 hour storm and if a
secondary BMP is used to treat the discharge from the pond, i.e., effective infiltration. A 90% TSS wet
pond has no bypass or VFS requirement so designing the pond to store 2.5 times the design storm
does not achieve anything. The design storm is discharged (pumped in this case) to the secondary
BMP (infiltration basin) to be treated. An LSNFS is not required for any discharge from a secondary
BMP, so the secondary BMP does not need to store 2.5 times the volume.
Infiltration: The 2008 rules (alternative design) allow for a pumped infiltration system with a
"storage area" and an infiltration area. In this case, a bypass and LSNFS is required, but designing
the storage area per 16.3.9 of the BMP manual to hold- 2.5 times the required pre/post volume of the
1 year 24 hour storm can be used to eliminate that offline bypass and VFS. The pond is simply acting
as a storage device, and is not subject to wet pond design criteria, so there is no orifice requirement.
But, the total time it takes to pump the design storm up to the infiltration area and infiltrate it
completely, must still meet the 5 day "all gone" requirement. According to Section 16.3.10 of the BMP
Manual:
1. The volume of the runoff pumped to the infiltration basin during the 24 hour storm event cannot
be more than 25% of the total design storm runoff volume (2.5 times the 1 year 24 hour
pre/post volume difference);
2. The available storage volume in the storage pond between the sediment cleanout level and the
overflow elevation cannot be less than 75% of the total design storm runoff volume;
3. The sum of the two volumes above must equal or exceed the total volume associated with the
design storm.
Please let me know by May 11, 2016, how you would like to proceed so I can complete my review.
Thanks.
Linda Lewis, E.I.
Environmental Engineer III
Division of Energy, Mineral and Land Resources
Department of Environmental Quality
910-796-7215 Office
linda.lewis(a)_ncdenr.gov

Wilmington Regional Office
127 Cardinal Drive Extension
Wilmington, NC 28403
!'"Nothing Compares._
Email correspondence to and From this, address is subject to. the
North :aro!?ra Pubk, Recor(Js Law and may he, t sciosed to third Pa►#ies.

Lewis,Linda
From:
Lewis,Linda
Sent:
Thursday, May 05, 2016 6:01 PM
To:
'Dan Fisk'; Robert Balland
Cc:
Scott, Georgette; Weaver, Cameron
Subject:
RE: Surf City K-8 SW8 160410
Thanks so much for the information Dan. I will proceed with the review on the basis of a wet pond
with a pump as the drawdown device and infiltration as the secondary BIVIP. As per the Technical
Review Workgroup guidance approved on March 7, 2014, the use of a 90% wet pond that provides
storage for the pre/post 1 year 24 hour storm volume difference and discharges that volume to a
secondary BIVIP will meet the "effective infiltration.." requirement fog SA waters without the need to
have a separate vegetated filter or level spreader for the overflow. Any release of stormwater from the
secondary BMP would be at a non -erosive velocity at the edge of the buffer, or into wetlands that do
not have a direct conveyance do SA waters. As it would apply to the Surf City K-8 project, the pump
would be the orifice, and it's pump rate under TDH should be set to drawdown that 1 year 24 hour
pre/post volume within 2-5 days and discharge that volume to the secondary BIVIP to be infiltrated. If
the wetlands do not contain a conveyance to SA waters, and if the emergency overflow in the
infiltration basin is engaged, that runoff wouid need to be controlied to discharge at a non -erosive
velocity into the wetlands. You would need to provide revised plans, application documents,
supplements, O&Ni's and calculations for this design that doesn't include any "2 times" or "2.5 times"
the design volume.
am still concerned about the NOQ.A number and I'd like to understand how this works for future
projects, so I'm going to ask a lot of questions - I hope that is OK. I remember reading the narrative
about the fact that the selected depth fell within the 90% confidence interval, but I did not interpret
that to mean you picked a value that was lower than the mean reported on the Precipitation
Frequency table by NOAA. I thought you: were just being thorough in your narrative.
How does one determine which value in that range of values to choose? Other than for the obvious
reason of sizing BMP's for less volume, why did you choose a value on the low side of the range
instead of on the higher side of the range? Is the use of 3.5" a mathematically derived choice, or an
I&eenie-meenie-minie-moe" choice? What are the determining factors that go into choosing a particular
value in that 90% confidence range? Why did you not choose 4.0"? 1 would have reasoned that in the
absence of rain gauge data specific for your site, the mean value for the gauge location closest to the
site would be a conservative choice. Do you have specific rain gauge data for this site to support the
use of 3.5" vs. 4"? Are you saying that the distance from the site to the recording gauge location
is justification for choosing a lower number? Why is it not justification for choosing a higher number?
NOAA makes certain assumptions and/or follows certain mathematical formulas to extrapolate
precipitation depths for sites that are distant from the gauge site. What assumptions and formulas did
you use to arrive at the conclusion that a value of 3.5" was right for this site? I thought the point of
being able to enter lat and long into the NOAA site was to get a relatively accurate precipitation
frequency and depth estimate for that specific location based on extrapolated data derived by
accepted mathematical formulas and assumptions by NOAA.
Their Atlas 14 publication for North Carolina is definitely a snoozer — they use way too many big
words. I've only been able to read a few pages. If I find anything of use in there, I'll let you know.

Thanks for your time or. fhi:
_inda
From: Dan Fisk [mailto:[e-mail]]
Sent: Thursday, May 05, 2016 3:56 PM
To: Lewis,Linda <[e-mail]>; Robert Balland <[e-mail]>
Cc: Scott, Georgette <[e-mail]>; Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8 SW8160410
Linda
Thank you for your email and additional information so we can clarify the intent of the design. You are correct in that
the current design took into account for the pumped infiltration basin language as well as the typical infiltration basin
language resulting in the "2 times" or "2.5 times" the volume depending on the option as you mentioned. To further
clarify; it is true that the 90% TSS Wet Ponds receive and treat all proposed impervious surface runoff from the Site as
the Primary BMP with the Infiltration Basins being secondary treatment for the Wet Ponds required and provided water
quality volume (WQV) which is received either by gravity/pipe (Wet Pond #1 and #2) or through a pump (Wet Pond #3
and #4) as mentioned. Furthermore, any storm runoff beyond the required and provided WQV would be discharged by
way of the Wet Ponds spillway/outlet structure through the Site's current drainage patterns (wetlands).
We would obviously prefer to have the site be designed with the 90%TSS removal as the primary BMPs and the
infiltration basins acting as secondary BMPs to treat the Wet Ponds WQV discharge and remove any multiples of the
required WQV storage that has been implemented in the current calculations if a LS/VFS will not be required due to this
set up? I'm assuming I need to get you revised calculations (and anything else that gets revised due to the change) that
remove the multiple applied to the WQV?
As for the NOAA precipitation depth selected, I did not hide the manner in which I arrived at a 3.5 inch depth for the
Site, and it was not my intent to give the impression that I was changing any data. As referenced in the Narrative under
the Design Method section, the rainfall depth selected was taken from the NOAA Atlas 14 PFDS 90% confidence interval
(the smaller numbers that give a range in parenthesis in the chart). As we all know, the NOAA depths are derived and
updated on a continual basis from Data received at multiple gauges; however, these gauges can be located far away
from a specific site and therefore rely on mathematical assumptions to get to the bold number in the chart that you
referenced. Due to those assumptions, the standard deviation or 90% confidence interval is derived and provided in the
chart. Furthermore, counties and municipalities that have implemented stormwater management ordinances with
specified rainfall depths to be used for incremental storms will rarely match the bold number from a site specific NOAA
Atlas 14 table; however, the majority of the specified rainfall depths from those ordinances will fall within the 90%
confidence interval. Therefore, I believe that selecting a rainfall depth within the 90% confidence interval meets the
intent of the broader, multiple year span of what the 1-year 24-hour site specific rainfall depth could be.
Thank you,
Daniel J. Fisk, PE
IPARAMOUNTE ENGINEERIWG, !NC.
59110leander Drive, Suite 201
Wilmington, NC 28403
910-791-6707 (P)
910-791-6760 (F)
[e-mail]
www.paramounte-eng.com

Lewis,Linda 2olCo 05 2I ckt l
From: Lewis,Linda
Sent: Wednesday, May 04, 2016 6:07 PM
To: 'Robert Balland'; Dan Fisk ([e-mail])
Cc: Scott, Georgette; Weaver, Cameron
Subject: Surf City K-8 SW8 160410
Hey Rob and Dan:
Before I get too deep into this Express review, I need for you to help me understand exactly what
option we are permitting for this site so I can tailor the rest of my review comments to that option.
During our meeting, I thought you told me that the infiltration basins were the secondary BMP's for
the wet ponds, but you've designed the ponds for "2 times" the design storm volume, so I am not sure
now. You may be mixing up the design requirements for a wet pond within'/ mile of SA waters and
pumped infiltration, which is understandable given the many design options we have today.
Because of the proximity to SA waters, the design storm is the 1 year 24 hour storm. When I print out
the NOAA precipitation depth chart using the same latitude and longitude you did, the 1 year 24 hour
depth is shown as 3.72 inches, but the form you provided with the calculations appears to have been
manually changed to 3.5 inches. Under what authority were you allowed to change the NOAA data?
Please use the 3.72 inch precipitation depth and submit new calculations. This results in additional
minimum storage volume requirements.
The wet ponds were designed to have storage for "2 times" the design storm. However, I'm not sure
that we can apply the infiltration basin volume options in Section 16.3.9 of the BMP Manual to wet
pond design. Please note that if you design the infiltration basin to hold only "2 times" the design
storm volume, you will only get to eliminate either the bypass or the VFS, but not both. To eliminate
both, Option 3 of the manual requires either active storage volume for "2.5 times" the design storm, or
(Option 4) demonstrate that the basin can infiltrate the 10 year 24 hour storm event without
discharging at % of the reported infiltration rate.
I think there are 2 design options here for your consideration:
Wet Pond: If you choose to design as a "Wet Pond", you don't need to design the pond to hold "2.5
times" the volume. The 2008 rules allow the use of a wet pond within Y2 mile of SA waters if the
storage volume is the greater of 1.5" or the pre/post volume for the 1 year 24 hour storm and if a
secondary BMP is used to treat the discharge from the pond, i.e., effective infiltration. A 90% TSS wet
pond has no bypass or VFS requirement so designing the pond to store 2.5 times the design storm
does not achieve anything. The design storm is discharged (pumped in this case) to the secondary
BMP (infiltration basin) to be treated. An LSNFS is not required for any discharge from a secondary
BMP, so the secondary BMP does not need to store 2.5 times the volume.
Infiltration: The 2008 rules (alternative design) allow for a pumped infiltration system with a
"storage area" and an infiltration area. In this case, a bypass and LS/VFS is required, but designing
the storage area per 16.3.9 of the BMP manual to hold 2.5 times the required pre/post volume of the
1 year 24 hour storm can be used to eliminate that offline bypass and VFS. The pond is simply acting
as a storage device, and is not subject to wet pond design criteria, so there is no orifice requirement.
But, the total time it takes to pump the design storm up to the infiltration area and infiltrate it

completely, must still meet the 5 day "all gone" requirement. According to Section 16.3.10 of the BMP
Manual:
1. The volume of the runoff pumped to the infiltration basin during the 24 hour storm event cannot
be more than 25% of the total design storm runoff volume (2.5 times the 1 year 24 hour
pre/post volume difference);
2. The available storage volume in the storage pond between the sediment cleanout level and the
overflow elevation cannot be less than 75% of the total design storm runoff volume;
3. The sum of the two volumes above must equal or exceed the total volume associated with the
design storm.
Please let me know by May 11, 2016, how you would like to proceed so I can complete my review.
Thanks.
Linda Lewis, E.I.
Environmental Engineer III
Division of Energy, Mineral and Land Resources
Department of Environmental Quality
910-796-7215 Office
lir Div=furl=!u�ncdenr.%ov
Wilmington Regional Office
127 Cardinal Drive Extension
Wilmington, NC 28403
'Nothing Compares -
Emi, espondeoce to and from this address is suoje;;t io fl7e
Norli, -�rolina Public .Records Lam and may be disclosed to third parties.

Precipitation Frequency Data Server
Page 1 of 4
NOAA Atlas 14, Volume 2, Version 3
(j)
Location name: Hampstead, North Carolina,US*
Latitude: 34.46280, Longitude:-77.57".
Elevation: 36 ft*
* source: Google Maps
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Mal
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)'
Duration
Average recurrence interval (years )
00�
10
25
50
100 200
500
1000
5-min
0.600
(0.464-0.542)
0.594
0.550-0.643)
0.695
(0.642-0.751)
0.774
(0.713-0.836)
0.873
(0.801-0.942)
0.949
(0.867-1.02)
1 1.03 1.10
(0.931-1.11) (0.995-1.19)
1.20
(1.07-1.30
1.28
(1.14-1.39)
10-min
0.799
0.950
1.71
1.24
1.39
1.51
1.63 1.76
1.90
2.02
(0.740-0.865)
(0.880-1.03)
(1.03-1.20)
(1.14-1.34)
(1.28-1.50)
(1.38-1.83)
(1.48-1.76) (1.58-1.89)
(1.70-2.06)
(1.79-2.19)
15-min
0. 2591..08
1.11. 1.29)
1.3041.52
(1.4451.69)
1 (1.2-1..90)
(1.75 2.06)
(1.87-2.22) l(1. 9-2.38)
1(2.1432.59
22 552.75
1.37
1.65
2.00
2.27
2.61
3.43
3.81
4.11
30-min
(1.27-1A8
1.53-1.79)
(1.85-2.16)
2.09-2.45)
2.40-2.82
(2 �83 11 )
(2.83.16
7-3.41) (3.10-3.71)
(3.40-4.13
( 3.64-4.46)
1.71
2.07
F 2.56
2.95
3.48
1 3.90
4.35 4.81
5.46
6.0
60-min
(1.56-1.85)
(1.92-2.24)
(2.37-2.77)
(2.72-3.19)
(3.19-3.75)
(3.57-4.21)
(3.95-4.69) (4.34-5.20)
( 4.88-5.92
(5.31-6.51 )
2.08
2.54
3.23
3.79
4.60
5.28
6.02 6.82
7.98
8.97
2-hr
(1.92-2.26)
(2.34-2.76)
(2.97-3.51)
(3.48-4.13)
(4.20-5.00)
(4.80-5.73)
(5.43-6.54) (6.11-7.40)
7.08-8.69
(7.89-9.80)
2.
4.
3-hr
(2.0B 45
(2. 2-3.00
3.2143.82)
(3.7814.52)
4. 205.54
5.3396.43
(6.09a7..41 (B. 278.49
8.15- 0.1)
(9.1801 6)
2.74
3.35
4.29
5.09
6.27
7.30
6.44 9.71
11.6
13.3
6-hr
(2.51-3.U2)
1 (3.07-3.69
(3.91-4.73)
(4.63-5.60)
1 (5.67-6.89)
1(6.55-8.01)
(7.51-9.25) (8.55-10.6)
1(10.1-12.8
(11.4-14.6
3.23
3.94
5.08
6.06
7.53
8.61
10.3 11.9
14.4
1B.6
12-hr
(2.93-3.60)
(3.58-4.39)
(4.60-5.65)
(b.46-6. (3)
(6.73-8.33)
(7.82-9.74)
( 9A 1.3) (10.3-13.1 )
( 12.3-15.9 )
( 14.0-18.3 )
3.72
4.51
5.84
6.99
8.73
10.3
12.0 13.9
24-hr
(3.42-4.09)
(4.15 4.97)
(5.36-6.42)
(6.39-7.66)
(7.90-9.55)
(9.19-11.2 )
( 10.6-13.1) (12.2-15.3)14.4-18.6
16.4-21.6
5-5.78)
6.
2-day
(3.98-4.77)
6.1677.42
7.09
. 008.83
8.40
(9.019161.0
10.4
(105- 2.9
12.1
12A 5.0) 138518.5
13.9 16.0
(16.3-21.3
19.3
16. 24.E
22.1
4.59
5.55
3-day
(4.22-5.04)
(5.10-6.10)
(6.49-7.78)
(7.66-921) 11
(9.37-11.4)
10.8-13.2
12.4-15.3) (14.1-17.7)
(16.6-21.4
(18.7-24.7)
4.85
5.8E
7.44
8.77 1
10.7 1
12.4
14.3 1 16.3 1
19.5
22.2
4-day
(4.46-5.31)
(5.39-6.42)
6.82-8.15)
(8.01-9.60)
(9.74-11.7)
11.2-13.6)
(12.7-15.6) (14.4-17.9)
16.8-21.6
( 18.9-24.8 )
5.59
6.74
8.47
9.92
12.0
13.8
16.7 17.7
20.7
23.3
7-de y
(5.17-6.08)
(6.23-7.32)
(7.87_-920)
(9.12-10.8)
(11.0-13.0)
(12.5-15.0)
(14.1-17.1) (15.8-19.3)
(18.2 22.8)
(20.1-25.7)
IF
10-day
57827
6.934812
8.572 0.0
9.91011.
11 8-14.0
13.4- 5.9
150E 8.1 16. g 0.4
19.27'23.8
21.0- 6.7
8.27
9.8E
12.0
73.E
16.3
18.4
20.5 22.9
26.1
28.8
20-day
(7.73-8.89)
(9.20-10.6)
11.2-12.9)
(12.8-14.8)
(15.0-17.5)
(16.9-19.7)(18.7-22.1)(20.6-24.7)
(23.2-28.4
(25.3-31.5)
10.1
74.4
16.4
19.1
21.3
23.5 25.E
28.8
31.4
30�ay
(9.51-10.8)
(11.312.0
-12.8)
13.6-15.4)
(15.4-17.5)
(17.8-20.4)
(19.7-22.
26.0
(24.1-27.9)
( 21.7-25.1) (23.6-27.7 )
28.7 31.5
(26.5-30.8) (28.8-338)
( 26.2-31.3
( 28.2-34.1 )
45-day
12.7
(12.0-13.8)
15.0
(14.1-16.1)(16.8-19.1)(18.9-2'1.6)
17.9
20.2
23.4
(21.8-25.1)
15.4
18.1
213
238
27.2
29.9
32.E 35.3
M
41.7
(14.5-16.3)
(17.1-19.3)..(22.4-25.3)
(25.5-28.9)
(28.0-31.8)
(30.3-34.7) (32.6-37.7)
(37.9-45.0)
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates
(for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper
bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
http://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.4628&lon=-77.5744&data 5/4/2016

PARAMOUNTE
E N CC 1 N E E R 1 N G, 1 N C.
5 9 1 1 OLEANDER DRIVE, SUITE 2 0 1
vW I L M I N G T O 1i-I , NC 2 8 4 0 3
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L E T T E R O F T R A N S M T 'T Ir A T.
To:
NCDENR
Date
1 04.28.16
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re:
Surf City K-8 School
Shepards Road
Attn:
Pro'ect No.
I 15348YE
e are sen ® Originals ® Prints
he folio items: ❑ Correspondence ® Plans
❑ Shop Drawings ® Calculations
❑ Specifications ® Other as listed below
Quantity
Date
Dwg. No.
Description
2
04.27.16
30"x 42" Design Documents
2
Form SWU-101 (I Original,1 Copy)
2
FRO Form — Express (1 Original, 1 Copy)
1
SWM and EC Narrative
1
$4,000 Review Fee (Check 292143)
1
O&M (Storm EZ)
1
4 Wet Pond Supplements
1
3 Infiltration Basin Supplements
1
2 Level Spreader and Veg Filter Supplements
ssue Status: Z For Approval ❑ As Requested ❑ Construction ❑ Bid
❑ For Your Use ❑ For Review and Comment ❑ Approved as Noted ❑ See Remarks
ction Taken: ❑ No Exceptions Taken ❑ Make Corrections Noted ❑ Amend & Resubmit
❑ Rejected - See Remarks ❑ Approved as Submitted ❑ Other
Cc: Signed: T
Daniel J. Fisk, PE

eye
PARAMOUNTE t�VW'
E N G 1 N E E Ft 1 N G, 1 " C.
5 9 1 1 O L E A N D E R D R I V E S U I T E 2 0 1
W I L M I NGT O N, N C 2 8 4 0 3
9 1 0- 7 9 1- 6 7 0 7( O) 9 1 0- 7 9 1- 6 7 6 0 ( F)
L F T T F R n F T R A N R M T 'P •r A T
To:
NCDENR
Date
1 04.29.16
127 Cardinal Drive Ext.
Wilmington, NC 28403
Re:
Surf City K-8 School
Shepards Road
Attn:
Linda Lewis
Pro'ectNo.
I 15348YE
e are sendin
❑ Originals
® Prints
❑ Shop Drawings
❑ Calculations
he following items:
❑ Correspondence
® Plans
❑ Specifications
❑ Other as listed below
Quantity
Date
Dwg. No.
Description
2
04.27.16
30"x 42" Site Layout Documents
2
SWU-101 — Revised with Superintendent signature (Original & Copy)
1
Storm EZ O&M Agreement
ssue Status: ® For Approval ❑ As Requested ❑ Co ci�on f�=
❑ For Your Use ❑ For Review and Comment ❑ Approved as No �V n Ae Reiiiar
ction Taken: ❑ No Exceptions Taken ❑ Make Corrections Noted
❑ Rejected - See Remarks ❑ Approved as Submitted ❑ Other
emarks:
Cc. Signed: e :/.,LJ
Daniel J. Fisk, PE
N

ECS CAROLINAS, LLP "Setting the, Standard 6or:S.ervice"
Geatechr, r,ai a Construction Materi njs o Fnvironmentai a Facilities
E C E I V E1% February 22, 2016
Mr. Justin Whitley APR 2 9 20V
Barnhill Contraction Company
P.O. Box 31765 BY.� F / W4/v
Raleigh, North Carolina 27622
Reference: Report of Seasonal High Water Table Estimation and Infiltration Testing
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
Dear Mr. Whitley:
ECS Carolinas, LLP (ECS) recently conducted a seasonal high water table (SHWT) estimation
and infiltration testing within proposed stormwater best management practice (BMP) areas at
the proposed Surf City K-8 site off of Perkins Drive in Hampstead, Pender County, North
Carolina. This letter, with attachments, is the report of our testing.
Field Testing
On February 2, 2016, ECS conducted an exploration of the subsurface soil and groundwater
conditions at seven requested locations (1-1 through 1-7) shown on the attached Test Location
Plan (Figure 1). On February 19, 2016, ECS returned to the site to assess a requested three
additional borings (1-8 through 1-10). ECS determined the boring locations using a site plan
provided by Paramounte Engineering. The purpose of this exploration was to obtain subsurface
information of the in situ soils for the stormwater BMP areas. ECS explored the subsurface soil
and groundwater conditions by advancing one hand auger boring into the existing ground
surface at the requested boring locations. ECS visually classified the subsurface soils and
obtained representative samples of each soil type encountered. ECS also recorded the SHWT
and groundwater elevation observed at the time of the hand auger borings. The attached
Infiltration Testing Form provides a summary of the subsurface conditions encountered at the
hand auger boring locations.
The SHWT and groundwater elevation was estimated at the boring locations below the existing
grade elevation. A summary of the findings are as follows:
Location
SHWT
Groundwater
1-1
24 inches
30 inches
1-2
25 inches
36 inches
1-3
0 inches
8 inches
1-4
12 inches
24 inches
1-5
18 inches
42 inches
1-6
6 inches
16 inches
1-7
10 inches
24 inches
1-8
4 inches
15 inches
1-9
10 inches
24 inches
1-10
12 inches
30 inches
�p:A :'WrvrCes, PU.(: ECS cArn4ri3> LLP • ECS:;-nhal PLLC• ECS Hor.ECS Southeast, !,r• C + Ef_5 Teyas. U

Report of SHWT Estimation and Infiltration Testing
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
d
ECS has conducted ten infiltration tests utilizing a compact constant head permeameter near
the hand auger borings in., order to estimate the infiltration rate for the subsurface soils.
Infiltration tests are typically conducted at two feet above the SHWT or in the most restrictive
soil horizon. Tests in clayey conditions are conducted and calculated up to 30 minute intervals.
If an exact hydraulic Fcpnduciivity is necessary for these locations, then ECS recommends
collecting samples by advancing Shelby tunes and performing laboratory permeability testing.
Field Test Results
Below is a summary of the infiltration test results:
Location
Description
Depth
Inches/
hour
1-1
Black fine SAND w/ silt
16 inches
3.13
1-2
Black fine SAND w/ silt
18 inches
1.48
1-3
Black silty SAND
10 inches
<.001
1-4
Gray fine SAND w/silt
10 inches
2.15
1-5
Black silty SAND
20 inches
0.032
1-6
Black silty SAND
10 inches
<.001
1-7
Black silty SAND
10 inches
0.029
1-8
Gray fine SAND
10 inches
0.017
1-9
Black silty SAND
10 inches
0.012
1-10
Black silty SAND
18 inches
0.024
Infiltration rates and SHWT may vary within the proposed site due to changes in elevation and
subsurface conditions. The moisture content associated with the shallow groundwater
elevations observed on this site influenced the hydraulic conductivity results.
2

Report of SHWT Estimation and Infiltration Testing
Surf City K 8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Closure
ECS's analysis of the site has been based on our understanding of the site, the project
information provided to us, and the data obtained during our exploration. If the project
information provided to us is changed, please contact us so that our recommendations can be
reviewed and appropriate revisions provided, if necessary. The discovery of any site or
subsurface conditions during construction which deviate from the data Outlined in this
exploration should be reported to us for our review, analysis and revision of our
recommendations, if necessary. The assessment of site environmental conditions for the
presence of pollutants in the soil and groundwater of the site is beyond the scope of this
geotechnical exploration.
ECS appreciates the opportunity to provide our services to you on this project. If you have any
questions concerning this report or this project, please contact us at [phone].
Respectfully,
ECS CAROLINAS, LLP
K. Brooks Wail
Project Manager
bwalla-ecslimited.com
910-686-9114
Attachments: Figure 1 - Test Location Plan
Infiltration Testing Form
ASFE Document
W. Brandon Fulton, PSC, PWS, LSS
Environmental Department Manager
bfu lton O-ecsl i m ited . com
704-525-5152
3

0
Ik'
ce
-MM a ��► w J l +7Veri r /Nf ARAM' .
® APPROXIMATE BORING LOCATIONS
SCALE SHOWN ABOVE
Surf City K-8 Site
Hampstead, Ponder County,
North Carolina
ECS Project # 49.1386
ebruary 2nd and 19th, 2016
KBW
Nr
W � E
Figure 1— Boring Location Plan
Provided by: Google (Maps and
Paramounte Engineering

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-1 0-12" SP Gray fine SAND
12"-16" SM Black fine SAND w/silt
16"-36" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 24 inches below the
existing grade elevation.
Groundwater was encountered at 30 inches below the existing grade
elevation.
Test was conducted at 16 inches below existing grade elevation
Infiltration Rate: 3.13 per hour
Location Depth USCS
1-2 0-3"
SM
3"-10"
SP
10"-20"
SM
20"-30"
SP
Soil Description
Black silty SAND
Gray fine SAND
Black fine SAND w/silt
Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 25 inches below the
existing grade elevation.
Groundwater was encountered at 36 inches below the existing grade
elevation.
Test was conducted at 18 inches below existing grade elevation
Infiltration Rate: 1.48 per hour
Location Depth USCS
1-3 0-4" SM
4"-12" SP
Soil Description
Black silty SAND
Gray fine to med. SAND
Seasonal High Water Table was estimated to be at 0 inches below the
existing grade elevation.
Groundwater was encountered at 8 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: <0.001 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS
1-4 0-101, SM
10"-24" S P
Soil Description
Gray fine SAND w/silt
Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 12 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 2.15 per hour
Location Depth USCS Soil Description
1-5 0-16" SIP White fine SAND
16"-30" SM Black silty SAND
30"-48" SP Tan/orange/gray fine SAND w/clay
Seasonal High Water Table was estimated to be at 18 inches below the
existing grade elevation.
Groundwater was encountered at 42 inches below the existing grade
elevation.
Test was conducted at 20 inches below existing grade elevation
Infiltration Rate: 0.032 per hour
Location Depth USCS
1-6 0-101, SM
10"-24" SIP
Soil Description
Black silty SAND
Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 6 inches below the
existing grade elevation.
Groundwater was encountered at 16 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: <0.001 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-7 0-10" SM Gray fine SAND w/silt
10"-24" SM Black silty SAND
24"-36" SP Gray fine SAND
Seasonal High Water Table was estimated to be at 10 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.029 per hour
Location Depth USCS Soil Description
1-8 0-6" SM Black silty SAND
6"-24" SP Gray fine SAND
Seasonal High Water Table was estimated to be at 4 inches below the
existing grade elevation.
Groundwater was encountered at 15 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.017 per hour
Location Depth USCS Soil Description
1-9 0-10" SP Gray fine SAND
10"-14" SM Black silty SAND
14"-24" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 10 inches below the
existing grade elevation.
Groundwater was encountered at 24 inches below the existing grade
elevation.
Test was conducted at 10 inches below existing grade elevation
Infiltration Rate: 0.012 per hour

Infiltration Testing Form
Surf City K-8 Site
Hampstead, Pender County, North Carolina
ECS Project No. 49.1386
February 22, 2016
Location Depth USCS Soil Description
1-10 0-12" SP Gray fine SAND
12"-22" SM Black silty SAND
22"-30" SP Tan/orange/gray fine SAND
Seasonal High Water Table was estimated to be at 12 inches below the
existing grade elevation.
Groundwater was encountered at 30 inches below the existing grade
elevation.
Test was conducted at 18 inches below existing grade elevation
Infiltration Rate: 0.024 per hour

� Geolechrical Engiiieepino Report
�
Goolachnical Services Are Performed for
Specific Purposes, Persons, and Projects
Geotechnical engineers structure their services to meet the specific needs of
their clients. A geotechnical engineering study conducted for a civil engineer
may not fulfill the needs of a construction contractor or even another civil
engineer. Because each geotechnical engineering study is unique, each geo-
technical engineering report is unique, prepared solelyforthe client. No one
except you should rely on your geotechnical engineering report without first
conferring with the geotechnical engineer who prepared it. And no one - not
even you - should apply the report for any purpose or project except the one
originally contemplated.
Read the Full Report
Serious problems have occurred because those relying on a geotechnical
engineering report did not read it all. Do not rely on an executive summary.
Do not read selected elements only.
A Geotechnical Engineering Report is Based an
A Unique Set of Project -Specific Factors
Geotechnical engineers consider a number of unique, project -specific factors
when establishing the scope of a study. Typical factors include: the client's
goals, objectives, and risk management preferences; the general nature of the
structure involved, its'size, and configuration; the location of the structure
on the site; and other planned or existing site improvements, such as access
roads, parking lots, and underground utilities. Unless the geotechnical engi-
neer who conducted the study specifically indicates otherwise, do not rely on
a geotechnical engineering report that was:
• not prepared for you,
• not prepared for your project,
• not prepared for the specific site explored, or
• completed before important project changes were made.
Typical changes that can erode the reliability of an existing geotechnical
engineering report include those that affect:
• the function of the proposed structure, as when it's changed from a
parking garage to an office building, or from alight industrial plant
to a refrigerated warehouse,
elevation, configuration, location, orientation, or weight of the
proposed structure,
composition of the design team, or
project ownership.
As a general rule, always inform your geotechnical engineer of project
changes - even minor ones - and request an assessment of their impact.
Geotechnical engineers cannot accept responsibility or liability for problems
that occur because their reports do not consider developments of which they
were not informed.
Subsurface Conditions Can Change
A geotechnical engineering report is based on conditions that existed at the
time the study was performed. Do not rely on a geotechnical engineering
report whose adequacy may have been affected by: the passage of time; by
man-made events, such as construction on or adjacent to the site; or by natu-
ral events, such as floods, earthquakes, or groundwater fluctuations. Always
contact the geotechnical engineer before applying the report to determine if it
is still reliable. A minor amount of additional testing or analysis could prevent
major problems.
Most Gootechnical Findings Are Professional
Opinions
Site exploration identifies subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. Geotechnical engineers
review field and laboratory data and then apply their professional judgment
to render an opinion about subsurface conditions throughout the site. Actual
subsurface conditions may differ -sometimes significantly from those indi-
cated in your report. Retaining the geotechnical engineer who developed your
report to provide construction observation is the most effective method of
managing the risks associated with unanticipated conditions.
A Report's Recommendations Are Not Final
Do not overrely on the construction recommendations included in your re-
port. Those recommendations are not final, because geotechnical engineers
develop them principally from judgment and opinion. Geotechnical engineers
can finalize their recommendations only by observing actual

subsurface conditions revealed during construction. The geotechnical engi-
neer who developed your report cannot assume responsibility or liability for
the report's recommendations if that engineer does not perform construction
observation.
A Geotechnical Engineering Report Is Subject to
Misinterpretation
Other design team members' misinterpretation of geotechnical engineer-
ing reports has resulted in costly problems. Lower that risk by having your
geotechnical engineer confer with appropriate members of the design team
after submitting the report. Also retain your geotechnical engineer to review
pertinent elements of the design team's plans and specifications. Contractors
can also misinterpret a geotechnical engineering report. Reduce that risk by
having your geotechnical engineer participate in prebid and preconstruction
conferences, and by providing construction observation.
Do Not Redraw me Engmeer s Logs
Geotechnical engineers prepare final boring and testing logs based upon
their interpretation of field logs and laboratory data. To prevent errors or
omissions, the logs included in a geotechnical engineering report should
never be redrawn for inclusion in architectural or other design drawings.
Only photographic or electronic reproduction is acceptable, but recognize
that separating logs from the report can elevate risk.
Give Contractors a Complete Report and
Guidance
Some owners and design professionals mistakenly believe they can Irlaft
contractors liable for unanticipated subsurface conditions by limiting what
they provide for bid preparation. To help prevent costly problems, give con-
tractors the complete geotechnical engineering report, but preface it with a
clearly written letter of transmittal. In that letter, advise contractors that the
report was not prepared for purposes of bid development and that the report's
accuracy is limited; encourage them to confer with the geotechnical engineer
who prepared the report (a modest fee may be required) and/or to conduct ad-
ditional study to obtain the specific types of information they need or prefer.
A prebid conference can also be valuable. Be sure contractors have sufficient
time to perform additional study. Only then might you be in a position to give
contractors the best information available to you, while requiring them to at
least share some of the financial responsibilities stemming from unantici-
pated conditions.
Read Responsibility Provisions Closely
Some clients, design professionals, and contractors do not recognize that
geotechnical engineering is far less exact than other engineering disciplines.
This lack of understanding has created unrealistic expectations that have led
to disappointments, claims, and disputes. To help reduce the risk of such
outcomes, geotechnical engineers commonly include a variety of explanatory
provisions in their reports. Sometimes labeled "limitations" many of these
provisions indicate where geotechnical engineers' responsibilities begin
and end, to help others recognize their own responsibilities and risks. Read
these provisions closely. Ask questions. Your geotechnical engineer should
respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The equipment, techniques, and personnel used to perform a geoenviron-
mental study differ significantly from those used to perform a geotechnical
study. For that reason, a geotechnical engineering report does not usually re-
late any geoenvironmental findings, conclusions, or recommendations; e.g.,
about the likelihood of encountering underground storage tanks or regulated
contaminants. Unanticipated environmental problems have led to numerous
project failures. If you have not yet obtained your own geoenvironmental in-
formation, ask your geotechnical consultant for risk management guidance.
Do not rely on an environmental report prepared for someone else.
Obtain Professional Assistance To Deal with Mold
Diverse strategies can be applied during building design, construction, op-
eration, and maintenance to prevent significant amounts of mold from grow-
ing on indoor surfaces. To be effective, all such strategies should be devised
for the express purpose of mold prevention, integrated into a comprehensive
plan, and executed with diligent oversight by a professional mold prevention
consultant. Because just a small amount of water or moisture can lead to
the development of severe mold infestations, a number of mold prevention
strategies focus on keeping building surfaces dry. While groundwater, wa-
ter infiltration, and similar issues may have been addressed as part of the
geotechnical engineering study whose findings are conveyed in -this report,
the geotechnical engineer in charge of this project is not a mold prevention
consultant; nm of the services perhewd in commcdee with
on peteclu" enoomais study *TM *BOW or conducted
110, the pmTM of mold prevention. Proper finonentHum of
the recemmendedons conveyed M U& report wN not sf itself
he sOclent to prevet motel Mew ova* in or on Un struc-
ture 00e1
Rely on Your ASFE-Member Geotechnical
Engineer For Additional Assistance
Membership in ASFE/The Best People on Earth exposes geotechnical engi-
neers to a wide array of risk management techniques that can be of genuine
benefit for everyone involved with a construction project. Confer with your
ASFE-member geotechnical engineer for more information.
ASF=r=
The Best People on Earth
8811 Colesville Road/Suite G106, Silver Spring, MD 20910
Telephone:' 301/565-2733 Facsimile: 301/589-2017
e-mail: [e-mail] www.asfe.org
Copyright 2004 by ASFE, Inc. Duplication, reproduction, or copying of this document in whole or in pan, by any means whatsoever, is strictly prohibited, except with ASFB specific
written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of ASFE, and only for purposes
of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report Any other firm,
individual, or other entity that so uses this document without being anASFE member could be committing negligent or intentional (fraudulent) misrepresentation.
IIGER06045.0M

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Hydrologic Soil Group ender County, North Carolina
Main Tract
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — Ponder County, North Carolina (NC141)
Map unit symbol
Map unit name
Rating
Acres In AOI
Percent of AOI
LnA
Leon fine sand, 0 to 2
percent slopes
A/D
22.4
23.1 %
Ma
Mandarin fine sand
B/D
35.3
36.5%
Mu
Murville muck
A/D
39.1
40.4%
Totals for Area of Interest
96.8
100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long -duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or VD), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Natural Resources Web Soil Survey 1/11/2016
Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group—Pender County, North Carolina
Main Tract
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. None Specified
Tie -break Rule: Higher
usD,A Natural Resources Web Soil Survey 1/11/2016
Conservation Service National Cooperative Soil Survey Page 4 of 4

��� !II IIUIV�IA�III�IIRII UIV
Doc No: 20005574
Recorded: 12/17/2015 11:45:36 AM
Fee Amt: $25.00 Page 1 of 4
Excise Tax: $1.700.00
Pender County North Carolina
Sharon Lear Willoughby, Register of Deeds
BK 4611 PG 2697 - 2700 (4)
NORTH CAROLINA SPECIAL WARRANTY DEED
Excise Tax $ 1,700.00
Parcel Identifier No. 4226-92-2047-0000
Verified by County on the day of . 20 _
By:
Mail / Box to: Grantee
This instrument prepared by: Patricia W. Nystrom, Attorney
Brief description for the Index: 85 acres, Topsail Beach
This Deed made this //) 4L day of December 7015hPhvem-
RUDOLPH-MOORE PROPERTIES, LLC
a North Carolina limited liability company
Mailing Address:
1114 Clement Street, Suite D
Charlotte, North Carolina 28205
GRANTEE(S)
PENDER COUNTY BOARD OF EDUCATION
Property Address:
Atkinson Loop Road
Topsail Beach, North Carolina 28445
Mailing Address:
925 Penderlea Highway
Burgaw, North Carolina 29425
Enter in appropriate block for each party: name, address and, if applicable, character of entity (e.g., corporation or partnership)
The designation Grantor and Grantee as used herein shall include said parties, their heirs, successor, and assigns, and shall include
singular, plural, masculine, feminine or neuter as required by context.
WITNESSETH that Grantor, for a valuable consideration paid by Grantee, the receipt of which is hereby acknowledged, has and by
these presents does grant, bargain, sell and convey unto Grantee in fee simple, all that certain lot or parcel of land situated in the City
of Topsail Beach Township, Pander County, North Carolina, and more
particularly described as follows:
See Exhibill A attached hereto and made apart hereof
The property hereinabove described was acquired by Grantor by instrument recorded in Book 2973 ,. at page 74
All or a portion of the property herein conveyed includes or XX does not include the primary residence of a Grantor.
ECEIVE
APR 2 9 20%
BY: 5w�lcov410

BK 4611 PG 2698 DOC# 20005574
Bk 4611
Pg 2698
A map showing the above described property is recorded in Plat Book at Page _.
TO HAVE AND TO HOLD the aforesaid lot or parcel or land and all privileges and appurtenances thereto belonging to the Grantee in
fee simple.
And the Grantor covenants with the Grantee, that Grantor has done nothing to impair such title as Grantor received, and Grantor will
warrant and defend the title against the lawful claims of all persons claiming by, under or through Grantor, other than the following
exceptions:
i. Ali restrictions and easements of record, including but not limited to:
a. All matters shown on a map recorded in Map Book 2973 at page 74, Pender County Public Registry;
b. Rural Line Permit to Carolina Telephone and Telegraph recorded in Book 350 at page 358, Pender County,
Public Registry;
2. Ad valorem taxes for the current year which have been prorated between Grantor and Grantee, if applicable,
and which Grantee hereby assumes.
IN WITNESS WHEREOF, the Grantor has duly executed the foregoing as of the day and year first above wriam
RUDOLPH MOORE PROPERTIES, LLC
By::�f24e
Name: ohn C. Rudolph
Title: Manager
By: _au"
Name: Auh Grier
Title: Manager
STATE OF NORTH CAROLINA - COUNTY OF Mecklenburg ) SS:
I, *' en . Qs= a Notary Public of Said County and State,
certify that John C. R 1 either being personally known to me or proven by
satisfactory evidence (said evidence being a State -issued driver's license), personally came before me this day
and acknowledged that he is the Manager of RUDOLPH-MOORE PROPERTIES, LLC a
North Carolina limited liability company, and that he, as said manager, voluntarily executed the foregoing
instrument on behalf of said entity, with authority duly given.
WITNESS my hand and official seal this the 11f0 day of December ; 2015.
1t
(Seal)
►E. Mecklenburg County
My Commission Expires: My Commission E�epires

BK 4611 PG 2699 DOC# 20005574
Bk 4611
Pg 2699
STATE OF NORTH CAROL NA - COUNTY OF Mecklenburg ) SS:
I, AIl'1'1 Ve ee L. I &barSdy) . a Notary Public of Said County and State,
certify that Aubrey Grier . either being personally known to me or proven by satisfactory
evidence (said evidence being a State -issued driver's license), personally came before me this day and
acknowledged that she is the Manager of RUDOLPH-MOORE PROPERTIES. LLC
, a North Carolina limited liability company, and that she, as said manager, voluntarily executed the foregoing
instrument on behalf of said entity, with authority duly given.
ii�
WITNESS my hand and official seal this the _ q day of December 2015.
J ;1
,�,0%n1111JR4
S
*%I�orA9�' 9oa
Notary Public
I jj
Pat`�`�'$
• : Z :
Printed name:
m Qree_ I� uyi
A
�. �8� 1� .� * F
al�
My Commission Expires: .a J aocou
e

BK 4611 PG 2700 DOC# 20005574
Bk4GI t
EXMrr A P9 2700
Lesal Description
Tax Parcel ID: 4226-92-2047-0000
The following described lot or parcel of land located in Topsail Township, Pender County, North Carolina:
Beginning at an iron stake in the center of the run of Ring Branch, said beginning being the Northwest comer of
Tract No. IA, running thence with the northern boundary line of Tract No. 1A, South 86 degrees 45 minutes
East passing through a traklin bed 2371 feet to an iron stake in the Fastens boundary line of the said division,
also the Southeast comer of Tract No. 3 and the Northeast comer of Tract No. IA; thence North 27 degrees 43
minutes East 900 feet to an iron stake; thence North 52 degrees 20 minutes West 1056 feet to an iron stake;
thence North 27 degrees 43 minutes East 415.5 feet to an iron stake in a stump hole which is on the Eastern side
of a woods road, said corner being referenced by a marked gum known as the Batt's corner, running thence
North 59 degrees 13 minutes West 1171 feet to an iron stake known as the Batts corner, also the comer of John
Jacobs' land; thence South 40 degrees 18 minutes West 2543 feet, passing under an old live oak near a woods
road to a 30 inch in diameter marked maple with markings approximately 100 years old, also being referenced
by pointers on an 8 inch gum and a 16 inch gum in angles to the aforesaid corner; thence down and with the run
of Ring Branch a Southeasterly course approximately 600 feet to the beginning, containing 111.44 acres, more
or less, and known in the division as Tract No. 3, as shown on "Map of Property of W.S. Atkinson (Deceased)
Division Between Miss Lessie Beulah Atkinson, Lacy Norman Atkinson, and Edward Dennis Atkinson, Upper
Topsail Township, Pender County, North Carolina, January 14, 1955" prepared by Roscoe Sandlin, Registered
Surveyor, which map is incorporated herein by reference for a more complete and accurate description.

Operation & Maintenance Agreement 5-19
Project Name:
Project Location:
Surf City K-8 School
Shepards Road - Town of Surf City
mainienance records shall be kept on the following BMP(s). This maintenance record shall be kept in a log in a known set locatic
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 pollutant removal efficiency of the BMP(s).
The BMP(s) on this project include (check all that apply & co
Bioretention Cell
Quantity:
Dry Detention Basin
Quantity:
Grassed Swale
Quantity:
Green Roof
Quantity:
Infiltration Basin
Quantity:
Infiltration Trench
Quantity:
Level Spreader/VFS
Quantity:
Permeable Pavement
Quantity:
Proprietary System
Quantity:
Rainwater Harvesting
Quantity:
Sand Filter
Quantity:
Stormwater Wetland
Quantity:
Wet Detention Basin
Quantity:
Disconnected Impervious Area
Present:
User Defined BMP
Present:
3
2
4
O&M tables will be added automatically):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s): NW & NE of Bus Parking, West PL
Location(s):
Location(s): Wet Pond #3 and Wet Pond #4
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s): One at each - N, W, S, and E of Building
Location(s):
Location(s):
I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for
each BMP above, and attached O&M tables. I agree to notify NCDENR of any problems with the system or prior to any changes to
the system or responsible party.
* Responsible Party:
Title & Organization:
Street address:
City, state, zip:
Phone number(s):
Email:
926 Pendei
urnaw, NC
Services
Signature: ,�f'—_ — ,C /"g, �� Date:10
I , a Notary Public for the State of
County of do hearby certify that fywy
personally appeared before me this —2 day of �F o? d� and
acknowledge the due execution of the Operations and Maintenance Agreement.
Witness my hand and official seal, CCC a o
ae `'� APR 2 9 ��s1
�rIPA
My commission expires /1) -/4/ A0/9
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 1 of 7

Level Spreader -Vegetated Filter Strip / Restored Riparian Buffer Maintenance Requirements
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 1.6 inches if in a Coastal County). Records of operation 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:
Potentialproblem:
How to remediate theproblem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the BMP
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Vegetation is too short or too
Maintain vegetation at a height of approximately six inches.
long.
The flow splitter device (if
The flow splitter device is
Unclog the conveyance and dispose of any sediment off -site.
applicable)
clogged.
The flow splitter device is
Make any necessary repairs or replace if damage is too large for repair.
damaged.
The inlet device
The pipe is clogged.
Unclog the pipe. Dispose of the sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged.
Erosion is occurring in the
Regrade the swale if necessary to smooth it over and provide erosion
swale.
control devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Stone verge is clogged or
Remove sediment and replace with clean stone.
covered in sediment (if
applicable).
RECEIVED
APR 2 9 1016
BY:
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 2 of 7

LS VFS f Restored Riparian Buffer Maintenance Requirements (Continued)
The swale and the level lip
The swale is clogged with
Remove the sediment and dispose of it off -site.
sediment.
The level lip is cracked,
Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the
end of the level spreader that
shows stormwater has
bypassed it.
Regrade the soil to create a berm that is higher than the level lip, and
then plant a ground cover and water until it is established. Provide lime
and a one-time fertilizer application.
Trees or shrubs have begun to
Remove them.
grow on the swale or just
downslope of the level lip.
The bypass channel
Areas of bare soil and/or
erosive gullies have formed.
Regrade the soil if necessary to remove the gully, and then reestablish
proper erosion control.
Turf reinforcement is damaged
or ripap is rolling downhill.
Study the site to see if a larger bypass channel is needed (enlarge if
necessary). After this, reestablish the erosion control material.
The filter strip
Grass is too short or too long
(if applicable).
Maintain grass at a height of approximately three to six inches.
Areas of bare soil and/or
erosive gullies have formed.
Regrade the soil if necessary to remove the gully, and then plant a
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Sediment is building up on the
filter strip.
Remove the sediment and restabilize the soil with vegetation if
necessary. Provide lime and a one-time fertilizer application.
Plants are desiccated.
Provide additional irrigation and fertilizer as needed.
Plants are dead, diseased or
dying.
Determine the source of the problem: soils, hydrology, disease, etc.
Remedy the problem and replace plants. Provide a one-time fertilizer
application.
Nuisance vegetation is
choking out desirable species.
Remove vegetation by hand if possible. If pesticide is used, do not
allow it to get into the receiving water.
The receiving water
Erosion or other signs of
damage have occurred at the
Contact the NCDENR local Regional Office, or the 401 Oversight Unit
at 919-733-1786.
outlet.
G E IVE
APR 2 5 zu]b
PY.
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 3 of 7

ST
Version 1.4
Infiltration System Maintenance Requirements
Important maintenance procedures:
- The drainage area will be carefully managed to reduce The sediment load to The infiltration basin.
_ Immediately after the infiltration basin is established, the vegetation will be watered twice weekly if needed until
the plants become established (commonly six weeks).
_ No portion of the infiltration basin will be fertilized after the initial fertilization that is required to establish the
vegetation.
- The vegetation in and around the basin will be maintained at a height of approximately six inches.
After the infiltration basin is established, it shall be inspected once a quarter and within 24 hours after every storm event greater
than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance shall be kept in a known set
location and shall be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
BMP element:
Potential problem:
How to remedlate the problem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
infiltration basin
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
The Inlet device: pipe or
The pipe is clogged (if
Unclog the pipe. Dispose of the sediment off -site.
swale
applicable).
The pipe is cracked or
Replace the pipe.
otherwise damaged (if
applicable).
Erosion is occurring in the
Regrade the swale if necessary to smooth it over and provide erosion
swale (if applicable).
control devices such as reinforced turf matting or riprap to avoid future
�tt
problems with erosion.
The forebay
Sediment has accumulated
Search for the source of the sediment and remedy the problem if
and reduced the depth to 75%
possible. Remove the sediment and dispose of it in a location where it
of the original design depth.
will not cause impacts to streams or the BMP.
Erosion has occurred or riprap
Provide additional erosion protection such as reinforced turf matting or
is displaced.
riprap if needed to prevent future erosion problems.
Weeds are present.
Remove the weeds, preferably by hand. If pesticides are used, wipe
them on the plants rather than spraying.
The main treatment area
A visible layer of sediment has
Search for the source of the sediment and remedy the problem if
accumulated.
possible. remove the sediment and dispose of it in a location where it
will not cause impacts to streams or the BMP. Replace any media that
was removed in the process. Revegetate disturbed areas immediately.
Water is standing more than 5
Replace the top few inches of filter media and see if this corrects the
days after a storm event.
standing water problem. If so, revegetate immediately. If not, consult
an appropriate professional for a more extensive repair.
Weeds and noxious plants are
Remove the plants by hand or by wiping them with pesticide (do not
growing in the main treatment
spray).
area.
The embankment
Shrubs or trees have started
Remove shrubs or trees immediately.
to grow on the embankment.
An annual inspection by an
Make all needed repairs. ECEIVE
appropriate professional
shows that the embankment
needs repair.
APR 2 9� 2016
The outlet device
Clogging has occurred.
Clean out the outlet device. Dispose . the sediment off -site.
The outlet device is damaged
Repair or replace the outlet device.
The receiving water
Erosion or other signs of
Contact the local NC Department of Environment and Natural
damage have occurred at the
Resources Regional Office.
outlet.
O&M Manual
Page 4 of 7

Wet Detention Pond Maintenance ttequlirements
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one
is provided.
Important maintenance procedures:
Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the
basin should be watered twice weekly if needed, until the plants become established (commonly six weeks).
No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to
establish the plants on the vegetated shelf.
_ Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention
basin.
If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the
emergency drain should be minimized to the maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and within 24 hours after every storm event
greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance should be kept in a known
set location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
EMP element:
Potential problem:
How I will remediate the problem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the BMP
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Vegetation is too short or too
Maintain vegetation at a height of approximately six inches.
long.
The inlet device
The pipe is clogged.
Unclog the pipe. Dispose of the sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged.
Erosion is occurring in the
Regrade the swale if necessary to smooth it over and provide erosion
swale.
control devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Stone verge is clogged or
Remove sediment and replace with clean stone.
covered in sediment (if
applicable).
The forebay
Sediment has accumulated to
Search for the source of the sediment and remedy the problem if
a depth greater than the
possible. Remove the sediment and dispose of it in a location where it
original design depth for
will not cause impacts to streams or the BMP.
sediment storage.
Erosion has occurred.
Provide additional erosion protection such as reinforced turf matting or
riprap if needed to prevent future erosion problems.
Weeds are present.
Remove the weeds, preferably by hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf
Best professional practices
Prune according to best professional practices
show that pruning is needed to
maintain optimal plant health.
Plants are dead, diseased or
Determine the source of the problem: soils, hydrology, disease, etc.
dying.
Remedy the problem and replace plants. Provide a one-time fertilizer
application to establish the ground cover if a soil test indicates it is
necessary.
Weeds are present.
Remove the weeds, preferably by hand. If pesticide is used, wipe it on
the plants rather than spraying.
ECEIVE
APR 2 9 2016
STORM-EZ MY. 4/2712016
Version 1.4 O&M Manual Page 5 of 7

e
Wet Detention Pond Maintenance Requirements (Continued)
The main treatment area
Sediment has accumulated to
a depth greater than the
Search for the source of the sediment and remedy the problem if
possible. Remove the sediment and dispose of it in a location where it
original design sediment
will not cause impacts to streams or the BMP.
storage depth.
Algal growth covers over 50%
of the area.
Consult a professional to remove and control the algal growth.
Cattails, phragmites or other
invasive plants cover 50% of
Remove the plants by wiping them with pesticide (do not spray).
the basin surface.
The embankment
Shrubs have started to grow
Remove shrubs immediately.
on the embankment.
Evidence of muskrat or beaver
Use traps to remove muskrats and consult a professional to remove
activity is present.
beavers.
A tree has started to grow on
Consult a dam safety specialist to remove the tree.
the embankment.
An annual inspection by an
Make all needed repairs.
appropriate professional
shows that the embankment
needs repair, if applicable)
The outlet device
Clogging has occurred.
Clean out the outlet device. Dispose of the sediment off -site.
The outlet device is damaged
Repair or replace the outlet device.
The receiving water
Erosion or other signs of
Contact the local NC Department of Environment and Natural
damage have occurred at the
Resources Regional Office.
outlet.
The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not
readily penetrate into accumulated sediments.
ECI Ver
APR Z 9 2016
BY:
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 6 of 7

Wet Detention Pond Design Summa
Wet Pond Diagram
WET POND ID
FOREBAY ij I
MAIN POND
#1
Permanent Pool El.
35
Permanent Pool El.
35
Pretreatment other
Temporary Pool El:
Clean Out Depth:
36.6 Temporary Pool El:
Q415 Clean
36.6
No
than forebay?
Sediment Removal El:
27/31/27
Out Depth:
Sediment Removal El:
5
30
Has Veg. Filter? No
Bottom Elevation:
26/30/26
Bottom Elevation:
27
WET POND ID
FOREBAY
MAIN POND
#2
Permanent Pool El.
33
Permanent Pool El.
33
Pretreatment other
than forebay? No
Temporary Pool El:
Clean Out Depth:
Sediment Removal El:
35.55 Temporary Pool El:
4 Clean Out Depth:
29 Sediment Removal El:
35.55
6
27
Has Veg. Fifter? No
Bottom Elevation:
28
Bottom Elevation:
26
WET POND ID
FOREBAY
MAIN POND
#3
Permanent Pool El-
30
Permanent Pool El.
30
Pretreatment other No
than forebay?
Temporary Pool El:
Clean Out Depth:
Sediment Removal El:
31.85
5
25
Temporary Pool El: 31.85
Clean Out Depth: 5
Sediment Removal El: 25
Has Veg. Filter? Yes
Bottom Elevation:
1 24
Bottom Elevation:
24
WET POND ID
FOREBAY
MAIN POND
#4
Permanent Pool El.
34
Permanent Pool El.
34
Temporary Pool El:
35.05
Temporary Pool El:
35.05
Pretreatment other No
Clean Out Depth:
4
Clean Out Depth:
5
than forebay?
Sediment Removal El:
30
Sediment Removal El:
29
Has Veg. Filter? Yes
Bottom Elevation:
1 28
Bottom Elevation:
28
EGEIVE
APR 2 9 20%
BY:
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 7 of 7

,ice Ole
Operation & Maintenance Agreement
Project Name:
Project Location:
Surf City K-8 School
Shepards Road - Town of Surf City
Imaimenance recoras snap De Kept on the tonowing timpts). This maintenance record shall be kept in a log in a known set locatio
Any deficient BMP elements noted in the inspection will be ccrrccted, repaired, or replaced immediately. These deficiencies can
affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the BMP(s).
The BMP(s) on this project include (check all that apply & coi
Bioretention Cell
Quantity:
Dry Detention Basin
Quantity:
Grassed Swale
Quantity:
Green Roof
Quantity:
Infiltration Basin
Quantity:
Infiltration Trench
Quantity:
Level SpreaderNFS
Quantity:
Permeable Pavement
Quantity:
Proprietary System
Quantity:
Rainwater Harvesting
Quantity:
Sand Filter
Quantity:
Stormwater Wetland
Quantity:
'Net Detention Basin
Quantity:
Disconnected Impervious Area
Present
User Defined BMP
Present:
2
O&M tables will
Location(s):
Location(s):
Loca6on(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
Location(s):
and
I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for
each BMP above; and attached O&M tables I agree to notify NCDENR of any problems with the system or prior to any changes to
the system or responsible party.
Signature:
F it
County of
Responsible Party:
Title & Organization:
Street address:
City, state, zip:
Phone number(s):
Email:
;_'v\d4er"
personally appeared before me this
925 Penderlea Hwy
Burgaw, NC 28425
910-259.0133
�Jlt' Date: �� 4
k e a Notary Public for the State of
do hearby certify that f+'r i CO b
:2 + day of f- � I -2( 1I to and
acknowledge the due execution of the Operations and Maintenance
�Agreement.
Witness my hand and official seal,
OFFICIAL SEAL
NOMM110•HaanC M"
PENDERCOUMY, NC
eutw.
i my CWj M Bow tlMOi9_ �
My commission expires
-3• 19
ECEIVE
APR 2 9 2016
STORM-EZ W27:201 E
Version 1.4 O&A I01anuai page S of 7

Level Spreader -Vegetated Fitter Strip / Restored Riparian Buffer Malntenance Regalrements
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 necessarv.
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 operation 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 to remediate theproblem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the BMP
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
erosive gullies have formed_
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Vegetation is too short or too
Maintain vegetation at a height of approximately six inches.
long.
The flow splitter device (If
The flow splitter device is
Unclog the conveyance and dispose of any sediment off -site.
applicable)
clogged.
The flow splitter device is
Make any necessary repairs or replace if damage is too large for repair.
damaged.
The Inlet device
The pipe is clogged.
Unclog the pipe. Dispose of the sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged.
Erosion is occurring in the
Regrade the swals if necessary to smooth it over and provide erosion
swale.
control devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Stone verge is clogged or
Remove sediment and replace with clean stone.
covered in sediment (if
applicable).
ECEIVE.
APR 2 9 2016
By
STORM-EZ 412712016
Version 1.4 O&M Manual Page 2 of 7

LS-VFS I Restored Riparian Buffer Maintenance Requ rements (Continued)
The swale and the level lip
The swale is clogged with
Remove the sediment and dispose of it off -site.
sediment.
The level lip is cracked,
Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the
I Regrade the soil to create a berm that is higher than the level lip, and
end of the level spreader that
then plant a ground cover and water until it is established. Provide lime
shows stormwater has
bypassed it,
and a one-time fertilizer application.
Trees or shrubs have begun to
Remove them.
grow on the swale or just
downslope of the level lip.
The bypass channel
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then reestablish
erosive gullies have formed.
proper erosion control.
Tun` reinforcement is damaged
Study the site to see if a larger bypass channel is needed (enlarge if
or ripap is rolling 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 approximately three to six inches.
(if applicable).
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Sediment is building up on the
Remove the sediment and festabilize the soil with vegetation if
filter strip.
necessary. Provide lime and a one-time fertilizer application.
Plants are desiccated.
Provide additional irrigation and fertilizer as needed.
Plants are dead, diseased or
Determine the source of the problem: soils, hydrology, disease, etc.
dying.
Remedy the problem and replace plants. Provide a one-time fertilizer
application.
Nuisance vegetation is
Remove vegetation by hand if possible. If pesticide is used, do not
choking out desirable species.
allow it to get into the receiving water.
The receiving water
Erosion or other signs of
Contact the NCDENR local Regional Office, or the 401 Oversight Unit
damage have occurred at the
at 919-733-1786.
outlet.
ECEIVE
APR 2 9 201
STORM-EZ 4/27/2016
Version 1.4 O&M Manual Page 3 of 7

- The drainage area will be carefully managed to reduce The sediment load to the infiltration basin,
immediately after the infiltration basin is established, the vegetation will be watered twice weekly if needed until
the plants become established (commonly six weeks).
No portion of the infiltration basin will be fertilized after the initial fertilization that is required to establish the
vegetation.
- The vegetation in and around the basin will be maintained at a height of approximately six inches.
After the infiltration basin is established, it shall be inspected once a quarter and within 24 hours after every storm event greater
than 1.0 inches (or 1.5 Inches If In a Coastal County). Records of operation and maintenance shall be kept in a known set
location and shall be available upon request
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately
BMP element.
Potential problem:
Now to romediate the problem!
The entire BMP_
Trash/debris is present
_
Remove the trashidebris
The perimeter of the
Areas of bare soil and/or
Regrads ththee soil if necessary to remove the gully, and then plant a
Infiltration basin
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
The inlet device. pipe or
The pipe is clogged (if
_
Unclog the pipe. Dispose of the sediment off -site.
Swale
applicable).
The pipe is cracked or
Replace the pipe. w "
otherwise damaged (if
applicable)
Erosion is occurring in the
Regrade the swale pf necessary to smooth it over and provide erosion
Swale (if applicable).
control devices such as reinforced turf matting or nprap to avoid future
problems witn erosion.
5o forebay
Sediment has accumulated
Search for the source of the sediment and remedy the problem if
land reduced the depth to 75%
possible. Remove the sediment and dispose of it in a location where it
of the original design depth,
will not cause impacts to streams or the BMP,
Erosion has*occurregi �r riprap
Provide additional erosion protection such as reinforced turf matting or^
is displaced.
riprap if needed to prevent future erosion problems.
Weeds are present.
Remove the weeds, preferably by hand. If pesticides ate used; wipe
A visible layer of sediment has
them on the plants rather than spraying.
Search for the source the sediment and remedy the problem if�
The main treatment aria_
accumulated.
possible. Remove the sediment and dispose of it in a location where it
will not cause impacts to streams or the BMP Replace any media that
was removed in the process. Revegetate disturbed areas immediately
Water is standing more than 5
Replace the top few inches of filter media and see if this corrects the
days after a storm event.
standing water probAm. If so, revegetate immediately. If not, consult
an appropriate professional for a more extensive repair.
Weeds and noxious plants are
Remove the plants by hand or by wiping them with pesticide (do not
growing in the main treatment
spray).
area
The embankment
Shrubs or trees have started
to grow on the embankment
Remove shrubs or trees imm t C E 1 V E
An annual inspection by an
Make all needed repairs. 2 9 2018
appropriate professional
chows that the ombankment
needs re air.
6Y.
The outlet device
Clogging has occurred.
Clean out the outlet device- Dispose of the sediment off -site a
The outlet device Is damaged
Repair or replace the outlet device
The receiving water
Erosion or other signs of
Contact the local NC Department of Environment and Natural
damage have occurred at the
Resources Regions Office
outlet.
St
Version i 4
O&M Manuel
4l4 r/4ul w
Page 4 of 7

Wet Detention Pond Maintenance Requirements _T
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one
is provided.
Important maintenance procedures;
_ Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the
basin should be watered twice weekly if needed, until the plants become established (commonly six weeks).
No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to
establish the plants on the vegetated shelf.
Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention
basin.
If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the
emergency drain should be minimized to the maximum extent practical.
Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and within 24 hours after every storm event
greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance should be kept in a known
set location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately.
BMP element:
Potential problem:
How I will remedlate the problem:
The entire BMP
Trash/debris is present.
Remove the trash/debris.
The perimeter of the BMP
Areas of bare soil and/or
Regrade the soil if necessary to remove the gully, and then plant a
erosive gullies have formed.
ground cover and water until it is established. Provide lime and a one-
time fertilizer application.
Vegetation is too short or too
Maintain vegetation at a height of approximately six inches.
long.
The inlet device
The pipe is clogged.
Unclog the pipe. Dispose of the sediment off -site.
The pipe is cracked or
Replace the pipe.
otherwise damaged.
Erosion is occurring in the
Regrade the swale if necessary to smooth it over and provide erosion
swale.
control devices such as reinforced turf matting or riprap to avoid future
problems with erosion.
Stone verge is clogged or
Remove sediment and replace with clean stone.
covered in sediment (if
applicable).
The forebay
Sediment has accumulated to
Search for the source of the sediment and remedy the problem if
a depth greater then the
possible. Remove the sediment and dispose of it in a location where it
original design depth for
will not cause impacts to streams or the BMP.
sediment. storage.
Erosion has occurred.
Provide additional erosion protection such as reinforced turf matting or
riprap if needed to prevent future erosion problems.
Weeds are present.
Remove the weeds, preferably by hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf
Best professional practices
Prune according to best professional practices
show that pruning is needed to
maintain optimal plant health.
Plants are dead, diseased or
Determine the source of the problem: soils, hydrology, disease, etc.
dying.
Remedy the problem and replace plants. Provide a one-time fertilizer
application to establish the ground cover if a soil test indicates it is
necessary.
Weeds are present.
Remove the weeds, preferably by hand. If pesticide is used, wipe it on
the plants rather than spraying.
O R IE
APR 2 9 2013
STORM-EZ BY, 4/2712016
Version 1.4 08M Manual Page 5 of 7

Wet Detention Pond Maintenance Reaulrement- (Continued)
The main treatment area
Sediment has accumulated to
Search for the source of the sediment and remedy the problem if
a depth greater than the
possible. Remove the sediment and dispose of it in a location where it
original design sediment
will not cause impacts to streams or the BMP.
storage depth.
Algal growth covers over 50%
Consult a professional to remove and control the algal growth.
of the area.
Cattails, phragmites or other
Remove the plants by wiping them with pesticide (do F101 spray).
invasive plants cover 50% of
the basin surface.
The embankment
Shrubs have started to grow
Remove shrubs immediately.
on the embankment.
Evidence of muskrat or beaver
Use traps to remove muskrats and consult a professional to remove
activity is present.
beavers.
A tree has started to grow on
Consult a dam safety specialist to remove the tree.
the embankment.
An annual inspection by an
Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable
The outlet device
Clogging has occurred.
Clean out the outlet device. Dispose of the sediment off -site.
The outlet device is damaged IRepair
or replace the outlet device.
The receiving water
Erosion or other signs of
Contact the local NC Department of Environment and Natural
damage have occurred at the
Resources Regional Office.
outlet.
The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not
readily penetrate into accumulated sediments.
ECEIVE`
APR 2 9
BY:
STORM-EZ 4/2712016
Version 1.4 O&M Manual Page 6 of 7

Wet pond dlaaram
WET POND ID FOREBAY MAIN POND
#1
Permanent Pool El.
35
Permanent Pool El.
35
Pretreatment other
Temporary Pool El,
Clean Out Depth.
36.6 Temporary Pool El.
$�-Wf 6 Clean Out Depth-
36.6
5
No
.
than forebay?
Sediment Removal El:
27131/27
Sediment Removal El;
30
Has Vag Filter? No
Bottom Elevation
28130125
Bottom Elevation
27
POND ID
FOREBAY
MAIN POND
t—WET
t #2
Permanent Pool El.
33
Permanent Pool Et.
33
Temporary Pool El-
35.56
Temporary Pool El:
35.55
Pretreatment other No 1
Clam Cut Dopth:
4
Clean Out Depth-
6
than forebay?
Sediment Removal El:
29
Sediment Removal Et:
_
27
Has Vag. Fitter? No
Bottom Elevation,
28
Bottom Elevation
28
WET POND ID
FOREBAY
MAIN POND
#3 .
Permanent Pool Et.
30
Permanent Pool Et.
30
Temporary Pool El:
31.86
Temporary Pool El:
3185
Pretreatment other
Clean Out Depth.
3
Clean Out Depth-
5
than forebay?
Sediment Removal El.
_
25
Sediment Removal El-
25
Has Vag Filter? Yes
Bottom Elevation.
24
Bottom Elevation.
24
WET POND 1D
FOREBAY
MAIN POND
Permanent Pool El,
R 34
_
Permanent Pool St.
34
Temporary Poot El:
35.05
Temporary Pool Ell:
35.05
Pretreatment other Nn
Clean Out Depth:
4
Clean Out Depth.
5
than forebay?
Sediment Removal EL
30
Sediment Removal Fl-
2.9
Has Vag. Fitter? Yes
Bottom Elevation:
28
Bottom Elevation.
28
ECEIVE
APR 2 9 2016
BY.
STORM-EZ 412712016
Version 1-4 O&M Menual Page 7 of'?

Permit No. ��)
(to be provided by D Q)
`-IWA
C'
MODEM
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part ll1) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name
Surf City K-8 School
Contact person
Robert Ballard, PE
Phone number
910.791.6707
Date
04.27.16
Drainage area number
1
II. DESIGN INFORMATION
Site Characteristics
Drainage area
471,130 fe
Impervious area, post -development
247,100 fe
% impervious
52.45 %
Design rainfall depth -
3.5 in
Storage Volume: Non -SA Waters
Minimum volume required
-- ff
Volume provided
N h it'
Storage Volume: SA Waters
1.5" runoff volume
30,743 ff
Pre -development 1-yr, 24-hr runoff
6,871 ft3
Post -development 1-yr, 24-hr runoff
71,734 f?
Minimum volume required
64,863 e
Volume provided 135,913 ft3
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr storm peak flow required?
Y (Y or N)
1-yr, 24-hr rainfall depth
in
Rational C, pre -development
(unitless)
Rational C, post -development
(unitless)
Rainfall intensity: 1 -yr, 24-hrstorm
in/hr
Pre -development 1-yr, 24-hr peak flow
1.63 fe/sec
Post -development 1-yr, 24-hr peak flow
15.91 fe/seC
Pre/Post 1-yr, 24-hr peak flow control
14.28 ff/sec
Elevations
Temporary pool elevation
36.60 fmsl
Permanent pool elevation
35.00 fmsl
SHWT elevation (approx. at the perm. pool elevation)
fmsl
Top of 1 Oft vegetated shelf elevation
35.00 fmsl
Bottom of 1 Oft vegetated shelf elevation
34.00 fmsl
Sediment cleanout, top elevation (bottom of pond)
30.00 fmsl
Sediment cleanout, bottom elevation
27.00 fmsl
Sedimentstorage provided
3.00 ft
Is there additional volume stored above the state -required temp. pool?
Y C,' or N)
Elevation of the top of the additional volume
36.6 fmsl
OK
-`ggqlllllrlli-
ECEiVE�
APR 2 91016
Form SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & It. Design Summary, Page 1 of 2

Permit
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool
89,240 fe
Area REQUIRED, permanent pool
24,734 fe
SAIDA ratio
5.25 (unitless)
Area PROVIDED, permanent pool, pem�oa
79,800 f? OI<
Area, bottom of 1 Oft vegetated shelf, Aet ,,heir
68,435 If
Area, sediment cleanout, top elevation (bottom of pond), 41,md
37,450 fe
Volumes
Volume, temporary pool
135,913 fe OK
Volume, permanent pool, l .rf _Pw
301,910 fO
Volume, forebay (sum of forebays if more than one forebay)
62,480 le
Forebay % of permanent pool volume
20.7% % OK
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, �e�npw,
Area provided, permanent pool, P,.p.i
Average depth calculated
Average depth used in SAIDA, (L, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, 4,,,,,_,ci
Area, bottom of 10ft vegetated shelf, Aot_AW
Area, sediment cleanout, top elevation (bottom of pond), &,,,w
"Depth" (distance b/w bottom of'!;jft shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, (k, (Round to down to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if -non -circular)
Coefficient of discharge (C@
Drvina head (K)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge dfice or weir)
Storage volume drawdown time
Addftional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
90 %
Y (Y or N)
N (Y or N)
5.25 (unitless)
N (Y or N)
301,910 ft3
79,800 f?
�ft
It
Y (Y or N)
79,800 f?
68,435 If
Need 3 ft min.
37,450 If
4.00 ft
3.60 ft OK
3.5 ft OK
Y (Y or N)
6.00 in
N (k in
0.60 (unitless)
0.51 / 0.53 ft
N (Y or N)
(unitless)
(unitless)
ft
Ar ft
1.63 If/sec:
15.91 Iffsec
0.6810.69 if/sac /sec
F`4n.a�r •. �'w �� •�,,,,m c imt seater LnBh
y- y a N 'r•••••
InC,1 niAni d......J..........'.•..r.. —c 6zt.."n 2
2.2212.28 days � _.._ ...,....,,.... ...._ _ . . _ _,.,...
3 :1 OK
6 :1
...a
6 :1 OK
5.8:1 OK ECEIVE
V N ar N) OK
>/=1 ft OK
N (Y or N) OK —(Y or N) OK APR Z 9 2016
Y (Y or N) OK
Pump BY,
Form SW401-Wet Detention Basin-Rev.9-4/1 Bill Parts I. & II. Design Summary, Page 2 of 2

Permit No.�!%
(to be provided by D Q)
Aga
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part ///) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Surf City K-8 School
Contact person Robert Balland, PE
Phone number 910.791.6707
Date 04.27.16
Drainage area number 2
N. DESIGN INFORMATION
Site Characteristics
Drainage area
210,375 fe
Impervious area, post -development
99,125 fe
% impervious
47.12 %
Design rainfall depth
3.5 in
Storage Volume: Non -SA Waters
Minimum
4/fie
volume required
to
Volume provided
to
Storage Volume: SA Waters
1.5" runoff volume
12,466 ft
Pre -development 1-yr, 24-hr runoff
3,068 ft
Post -development 1-yr, 24-hr runoff
29,088 fO
Minimum volume required
26,020 ft3
Volume provided 52,050 if
Peak Flow Calculations
Is the prelpost control of the 1yr 24hr storm peak flow required?
Y (Y or N)
1-yr, 24-hr rainfall depth
Rational C, pre -development
—in
(unitless)
Rational C, post -development
(unitless)
Rainfall intensity: 1-yr, 24-hr storm
IF in/hr
Pre -development 1-yr, 24-hr peak flow
0.79 ft3/sec
Post -development 1-yr, 24-hr peak flow
4.32 f?/sec
Pre/Post 1-yr, 24-hr peak flow control
3.53 If/sec
Elevations
Temporary pool elevation
35.55 fmsl
Permanent pool elevation
33.00 fmsl
SHWT elevation (approx. at the perm. pool elevation)
fmsl
Top of 1 Oft vegetated shelf elevation
33.00 fmsl
Bottom of 1 Oft vegetated shelf elevation
32.00 fmsl
Sediment cleanout, top elevation (bottom of pond)
27.00 fmsl
Sediment cleanout, bottom elevation
26.00 fmsl
Sediment storage provided
1.00 It
Is there additional volume stored above the siafe-required temp. pool?
Y (Y or N)
Elevation of the top of the additional volume
35.6 fmsl
OK
gECEIVE
APR 2 9 2016
BY:
040501
10".0
,�,9ti1 • ��5
.0L J - .�
Form SW401-Wet Detention Basin-Rev.9-4/18/12
Parts I. & II. Design Summary, Page 1 of 2

Permit
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 24,063 flz
Area REQUIRED, permanent pool
8,562 fe
SAIDA ratio
4.07 (unifless)
Area PROVIDED, permanent pool, >�enn�m
16,580 i:'
OK
Area, bottom of 1 Oft vegetated shelf, Aut_sher
9,020 If
Area, sediment cleanout, top elevation (bottom of pond), 461.d
3,690 If
Volumes
Volume, temporary pool
52,050 fe
OK
Volume, permanent pool, �� pooi
52,630 f?
Volume, forebay (sum of forebays if more than one forebay)
10,588 fe
Forebay % of permanent pool volume
20.1 % %
OK
SAIDA Table Data
Design TSS removal
90 %
Coastal SAIDA Table Used?
Y (Y or N)
Mountain/Piedmont SAIDA Table Used?
N (Y or N)
SAIDA ratio
4.07 (unitess)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
N (Y or N)
Volume, permanent pool, nn�oa
52,630 fO
Area provided, permanent pool, �i
16,580 fe
Average depth calculated
It
Need 3 It min.
Average depth used in SAIDA, 4,,, (Round to nearest 0.5ft)
it
Calculation option 2 used? (See Figure 10-2b)
Y (Y or N)
Area provided, permanent pool, A. ,.I
16,580 t?
Area, bottom of'.Oft vegetated shelf, Pw shelf
9,020 fe
Area, sediment cleanout, top elevation (bottom of pond), #btymd
3,690 fe
'Depth' (distance b/w bottom of :uft shelf and top of sediment)
5.00 ft
Average depth calculated
3.90 ft
OK
Average depth used in SAIDA, cL, (Round to down to nearest 0.5ft)
4.0 ft
OK
Drawdown Calculations
Drawdown through orifice?
Y (Y or N)
Diameter of orifice (if circular)
3.00 in
Area of orifice ('If -non -circular)
04Pr in
Coefficient of discharge (C@
0.60 (unifless)
Driving head (H,
0.85 ft
Drawdown through weir?
N (Y or N)
Weir type
unifless)
Coefficient of discharge
(unifless)
Length of weir (L)
4 ft
Driving head (H)
ft
Pre -development 1-yr, 24-hr peak flow
0.79 ff/sec
Post -development 1-yr, 24-hr peak flow
4.32 ff/sec
Storage volume discharge rate (through discharge dflce or weir)
0.22 fe/sec
Storage volume drawdown time
_
2.76 days
OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
6 :1
Vegetated shelf width
6.0 ft
�a,tyll',.
Length of flowpath to width ratio
4 :1
OK
�� � ���
Length to width ratio
3.9 :1
OK
Trash rack for overflow x orifice?
Y (Y or N)
OK
APR 2
Freeboard provided
>I=1 ft
OK
9 20% -
Vegetated filter provided?
N Y or N
OK
Recorded drainage easement provided?
jq (Y or N)
OK
BY'
Capures all runoff at ultimate build -out?
Y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
Pump
Forth SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & II. Design Summary, Page 2 of 2

Permit
0 be provided by DWQ)
NCDENR'
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The RequiredItems Checklist (Part l//J must be printed, filled out and submitted abT with all of
the required information.
I. PROJECT INFORMATION
Project name
Surf City K-6 School
Contact person
Robert Ballard, PE
Phone number
910.791.6707
Date
04.27.16
Drainage area number
3
II. DESIM INFORMATION
Site Characteristics
Drainage area
431,420 ft'
Impervious area, post -development
153,000 ff
% impervious
35.46 %
Design rainfall depth
3.5 in
Storage Volume: Non -SA Waters
Minimum volume required
QUA- fe
Volume provided
N(A' fe
Storage Volume: SA Waters
1.5" runoff volume
19,909 fe
Pre -development 1-yr, 24-hr runoff
6,292 ff
Post -development 1-yr, 24-hr runoff
46,454 fe
Minimum volume required
40,162 fe
Volume provided
40,191 fe
Peak Flow Calculations
Is the pre/past control of the 1 yr 24hr storm neck flow required? N (Y or N)
1-yr, 24-hr rainfall depth
in
Rational C, pre -development
(unitiess)
Rational C, post -development
4 (unitiess)
Rainfall intensity: 1 -yr, 24-hrstorm
Pre -development 1-yr, 24-hr flow
40, in/hr
1.62
%���'(H CAgO,,.
••, ':
peak
Post -development 1-yr, 24-hr flow
ff /sec
.`� .•'FESS%p
'QQ��i�
peak
Pre/Post 1-yr, 24-hr peak flow control
19.60 ff/sec
17.98 fe/sec
�-
1
•�� _1 L
Elevations
_ _
OZ
O4O�05 1
Temporary pool elevation
31.85 fmsl
�• q�•
Permanent pool elevation
30.00 fmsl
'�NGINE�Q' •�
SHWT elevation (approx. at the perm, pool elevation)
fmsl
% Q `�
','����iE�
Top f 1 Oft vegetatedshelfelevation
30.00
````
otto f shelf elevation
fmsl
J' `i
nw% '
Sediment cleanout, top elevation (bottom of pond)
25,00 fmsl
Sediment deanout, bottom elevation
24.00 fmsl
Sediment storage provided
1.00 it
is there additional volume stored above the state -equired temp. pool? `r' (Y or N)
C C E I�I E
Elevation of the top of the additional volume
31.9 fmsl OK
I�
APR 2 9 2016
BY:
Form SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & II. Design Summary, Page 1 of 2

Permit
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 23,669 f?
Area REQUIRED, permanent pool
SA/DA ratio
Area PROVIDED, perr:lsnent pool, /'Pow
Area, bottom of 1 Oft vegetated shelf, Awo heif
Area, sediment cleanout, top elevation (bottom of pond), &,.d
Volumes
Volume, temporary pool
Volume, permanent pool, \�.._Pcd
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SA/DA Table Data
Design TSS removal
Coastal SA/DA Table Used?
Mountain/Piedmont SA/DA Table Used?
SA/DA ratio
Average depth (used in SA/DA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool,�d,,,,.i
Area provided, permanent pool, _rod
Average depth calculated
Average depth used in SA/DA, (L, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, 4,P-01
Area, bottom of 10ft vegetated shelf, Pdm_:helr
Area, sediment cleanout, top elevation (bottom of pond), tbtwa
'Depth" (distance blw bottom of 15ft shelf and top of sediment)
Average depth calculated
Average depth used in SA/DA, 4., (Round to down to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (If circular)
Area of orifice (if -non -circular)
Coefficient of discharge (Cq)
Driving head (N)
Drawdown through weir?
Weir type
Coefficient of discharge (C )
Length of weir (L)
Driving head (H)
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge dfice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
15,315 flz
3.55 (unitiess)
19,660 fe OK
15,645 fe
6,625 ff
40,191 fe OK
62,503 fe
12,625 fe
20.2°A % OK
90 %
Y (Y or N)
N (Y or N)
3.55 (unitless)
N (Y or N)
62,503 ft?
19,660 ff2
�ft
ft
Y (Y or N)
19,660 If
15,645 fe
Need 3 ft min.
6,625 fe
4.00 ft
3.30 ft OK
3.5 ft OK
Y (Y or N)
4.00 in
FA .4'. in2
0.60 (unitiess)
0.62 ft
N (Y or, N)
iiiiiie (unitless)
,00 (unitiess)
ft
It
1.62 fts/sec
19.60 fe/sec e��(efi MJ1l1L 'h4AClutr►l4r OR�woettrv�l
Varies � fetsec 910110, 41*.
3.13 days OK, draws down in 2-5 days.
3 :1 OK
�r
6.0 ft
..............
3 :1 OK �/
3.3:1 OK ECEI V E
Y (Y or N) OK
>/_, ft OK APR 2 9 2016
N (Y or N) OK
I (Y or N) OK
Y (Y or N) OK BY:
Pump
Form SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & It. Design Summary, Page 2 of 2

Permit No. MDWQ)e��'14
(to be provide
ATA
KDENR = �
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be tilled out, printed and submitted.
The Required Items Checklist (Part ill) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Surf City K-8 School
Contact person Robert Balland, PE
Phone number 910.791.6707
Date 04.27.16
Drainage area number 4
111. DESIGN INFORMATION
Site Characteristics
Drainage area
196,715 ffz
Impervious area, post -development
120,000 fe
% impervious
61.00 %
Design rainfall depth
3.5 in
Storage Volume: Non -SA Waters
Minimum
volume required
k fe
Volume provided
N fi
Storage Volume: SA Waters
1.5" runoff volume
14,729 ff
Pre -development 1-yr, 24-hr runoff
2,869 fe
Post -development 1-yr, 24-hr runoff
34,369 fe
Minimum volume required
31,500 fe
Volume provided
31,807 fe
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
Y (Y or N)
1-yr, 24-hr rainfall depth
in
Rational C, pre -development
(unitless)
Rational C, post -development
(unitless)
`' 111 r r 1 r i r "��'
Rainfall intensity:1 yr, 24-hr storm
in/hr
Pre -development 1-yr, 24-hr peak flow
0.68 ff /sec
QQ; •kEssly
Post -development 1-yr, 24-hr peak flow
13.67 fe/sec
�%%
2: Q`o �••••'� L
Pre/Post 1-yr, 24-hr peak flow control
12.99 fe sec
_ p
Elevations
L
Temporary pool elevation
35.05 fmsl
= ? 040501
Permanent pool elevation
34.00 fmsl
•
SHWT elevation (approx. at the perm. pool elevation)
fmsl
• �)� f`�.�
�'.� •••'••C�• IIVE''••�����
Top of 1 Oft vegetated shelf elevation
34.00 fmsl
:.'c`
Bottom of 1 Oft vegetated shelf elevation
33.00 fmsl
�gNIEL J •
Sediment cleanout, top elevation (bottom of pond)
29.00 fmsl
Sediment cleanout, bottom elevation
28.00 fmsl
Sediment storage provided
1.00 It
� � � � � ��
Is there additional volume stored above idle siaie-required temp, pool?
Y (Y or N)
Elevation of the top of the additional volume 35.1 fmsl OK APR 2 9 201t
Form SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & II. Design Summary, Page t of 2

Permit No.
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool
Area REQUIRED, permanent pool
SAIDA ratio
Area PROVIDED, permanent puui, J.j d
Area, bottom of 1Oft vegetated shelf, ki,,n,r
Area, sediment cleanout, top elevation (bottom of pond), &-,Id
Volumes
Volume, temporary pool
Volume, permanent pool,
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool,1 er,,,_P,
Area provided, permanent pool,
Average depth calculated
Average depth used in SAIDA, (L, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, Permanent pool, �e1,
Area, bottom of !Oft vegetated shelf, Ad_Bhdf
Area, sediment cleanout, top elevation (bottom of pond), &1- and
'Depth" (distance b/w bottom of lift shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, (k, (Round to down to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if -non -circular)
Coefficient of discharge (C❑)
Driving head (K)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge dfice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow 8 orifice?
Freeboard provided
Vegetated fitter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
32,103 e
13,986 If
7.11 (unitiess)
28,320 ftz OK
21,660 fe
7,000 flz
31,807 If OK
81,905 ft
16,113 ft3
19.7% % OK
90 %
Y (Y or N)
N (Y or N)
7.11 (unitless)
N (Y or N)
81,905 ff
28,320 fe
-0001 ft Need 3 ft min.
ft
Y (Y or N)
28,320 fe
_ 21,660 fe
7,000 fe
4.00 It
3.10 ft OK
3.0 ft OK
Y (Y or N)
6.00 in
in
0.60 (unitiess)
0.35 ft
N (Y or N)
(unitiess)
,00 (unitiess)
_ It
It
0.68 elsec
13.67 ff/sec Q0k "K04hWA 044liiia (LOU-1b t14KVV-1(LA
Varies MUM ff/sec r. MUM
3.02 days OK, draws down in 2-5 days.
3 :1 OK
6.Ip�„ft;,lo„+�tiaalo�
6: 2+ti ECEIVE
6 :1 OK
OK
Y 5.6 Y or N) OK APR 2 9 2015
>/=1 ft OK
N (Y or N) OK BY.
U (Y or N) OK
Y (Y or N) OK
Pump
Form SW401-Wei Detention Basin-Rev.9-4/18/12 Parts I. 8 II. Design Summary, Page 2 of 2

Permit No.
(to be provided by DWQ)
AWA
i STORMWATER MANAGEMENT PERMIT APPLICATION FORM = -.
WDENR 401 CERTIFICATION APPLICATION FORM
INFILTRATION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Pan ///) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project Name
Surf City K-8 School
Contact Person
Robert Balland, PE
Phone Number
910.791.6707
Date
04.27.16
Drainage Area Number
1
II. DESIGN INFORMATION
Site Characteristics
Drainage area
471,130.00 flz
Impervious area
247,100.00 fe
Percent impervious
52.45 %
Design rainfall depth
3.50 in
Peak Flow Calculations
1-yr, 24-hr rainfall depth
1-yr, 24-hr intensity
Pre -development 1-yr, 24-hr discharge
Post -development 1-yr, 24-hr discharge
Pre/Post 1-yr, 24-hr peak flow control
Storage Volume: Non -SA Waters
Minimum design volume required
Design volume provided
Storage Volume: SA Waters
1.5' runoff volume
Pre -development 1-yr, 24-hr runoff volume
Post -development 1-yr, 24-hr runoff volume
Minimum required volume
Volume provided
Soils Report Summary
Soil type
Infiltration rate
SHWT elevation
Basin Design Parameters
Drawdown time
Basin side slopes
Basin bottom elevation
Storage elevation
Storage Surface Area
Top elevation
Basin Bottom Dimensions
Basin length
Basin width
Bottom Surface Area
d�b
tQAF In
in/hr
fe/sec
IM/Ar fP/sec
1 -fe/sec
�e fe
30743.00 fts �`���Q►'�� CARQ�/���.
6,871.00 fe
71,734.00 fP �[
64863.00 fO QL _
135,913.00 fl3 OK 04050
Leon Fine Sand
34.00 f sl t�
J. F��.��.
11111 M %
4.22
days
OK
3.00
:1
OK
35.00
fsl
36.00
fmsl
11,060.00
le
37.00
fmsl
79.00 ft
,815.0 ft E C C I E
9,815.00 ilz C G �! G
APR Z 9 1
BY -
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWQ)
Additional Information
Maximum runoff to each inlet to the basin?
r1 mac
-in
Length of vegetative filter for overflow
NIA
It
OK
Distance to structure
>15
It
OK
Distance from surface waters
>50
ft
OK
Distance from water supply well(s)
>100
ft
OK
Separation from impervious soil layer
>1
ft
OK 4K bMIQ
Naturally occuring soil above shwt
0.67
tt
Bottom covered with 4-in of clean sand?
Y
(Y or N)
OK
Proposed drainage easement provided?
- 4 (Y or N)
Capures all runoff at ultimate build -out?
Y
(Y or N)
OK
Bypass provided for larger storms?
Y
(Y or N)
OK
Pretreatment device provided
Wet Pond
�ECEIVE�
APR 2 9 2016
BY -
Form SW401-Infiltration Basin-Rev.5 11Ap2011 Parts I. & II. Design Summary. Page 2 of 2

Permit No.
(to be provided by DWQ)
STORMWATER MANAGEMENT PERMIT APPLICATION FORM _Dula
WDENR 401 CERTIFICATION APPLICATION FORM
INFILTRATION BASIN SUPPLEMENT
This form must be filled out printed and submitted.
The Required Items Checklist (Part Ill) must be printed, filled out and submitted along with all of the required information.
Project Name
Contact Person
Phone Number
Drainage Area Number
K-8 School
Robert Balland, PE
910.791.6707
04.27.16
2
II. DESIGN INFORMATION
Site Characteristics
Drainage area
210,375.00
fle
Impervious area
99,125.00
fe
Percent impervious
47.12
%
Design rainfall depth
3.50
in
Peak Flow Calculations
1-yr, 24-hr rainfall depth
}�
in
1-yr, 24-hr intensity
inlhr
Pre -development 1-yr, 24-hr discharge
fOlsec
Post -development 1-yr, 24-hr discharge
1►
ft�/sec
Pre/Post 1-yr, 24-hr peak flow control
—ff /sec
MinimumStorage Volume: esi n Non -SA volume Waters
Design volume provided
fe
p• ft3
� �5:: - "�
�-
Storage Volume: SA Waters
•
1.5" runoff volume
12466.00 ft3L
Pre -development 1-yr, 24-hr runoff volume
3,068.00 fe
040501
Post -development 1-yr, 24-hr runoff volume
29,088.00 fe
�.,• Q��'�1e�V �°
Minimum required volume
26020.00 fP
•.•
��. ^/ (G�C;•',t
�"�
Volume provided
p
52,050.00 f?
OK
��, ����`�
�'10, '9/��
Soils Report Summary
Soil type
Leon Fine Sand
Infiltration rate
2.15 inlhr
SHWT elevation
32.00 fmsl
Basin Design Parameters
Drawdown time
4.23 days
OK
Basin side slopes
3.00 :1
OK
Basin bottom elevation
33.00 fmsl
�� ^ �� ��"�
"" -' "- +��_ '' " 2k-,- SFyAiT.
Storage elevation
34.00 fmsl"�r
Storage Surface Area
6,685.00 ff
Top elevation
35.00 fmsl
Basin Bottom Dimensions
Basin length
93.00 ft
Basin width
61.56 ft
Bottom Surface Area
5,725.00 f?
C
C C E I V G
APR 2 9 2016
BY:
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWQ)
Additional Information
Maximum runoff to each inlet to the basin?
ac4n
Length of vegetative filter for overflow
N/A It
OK
Distance to structure
>15 It
OK
Distance from surface waters
>50 ft
OK
Distance from water supply well(s)
>100 It
OK
Separation from impervious soil layer
>1 It
OK
Naturally occuring soil above shwt
0.67 It
Bottom covered with 4-in of clean sand?
Y (Y or N)
OK 'Sillili� 116�v
Proposed drainage easement provided?
64(Y or N)
Capures all runoff at ulfimate build -out?
Y (Y or N)
OK
Bypass provided for larger storms?
Y (Y or N)
OK
Pretreatment device provided
Wet Pond
EGGIVE
WR 2 u 201b
BY:
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 2 of 2

Permit No.
(to be provided by O WQ)
STORMWATER MANAGEMENT PERMIT APPLICATION FORM'
WNW 401 CERTIFICATION APPLICATION FORM
INFILTRATION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project Name
Surf City K-8 School
Contact Person
Robert Balland, PE
Phone Number
910.791.6707
Date
04.27.16
Drainage Area Number
3 1& 4:
11. DESIGN INFORMATION
Site Characteristics
Drainage area
628,135.00 fly
Impervious area
273,000.00 fe
Percent impervious
43.46 %
Design rainfall depth
3.50 in
Peak Flow Calculations
1-yr, 24-hr rainfall depth
1-yr, 24-hr intensity
Pre -development 1-yr, 24-hr discharge
Post -development 1-yr, 24-hr discharge
Pre/Post 1-yr, 24-hr peak flow control
Storage Volume: Non -SA Waters
Minimum design volume required
Design volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre -development 1-yr, 24-hr runoff volume
Post -development 1-yr, 24-hr runoff volume
Minimum required volume
Volume provided
Soils Report Summary
Soil type
Infiltration rate
SHWT elevation
Basin Design Parameters
Drawdown time
Basin side slopes
Basin bottom elevation
Storage elevation
Storage Surface Area
Top elevation
Basin Bottom Dimensions
Basin length
Basin width
Bottom Surface Area
gala.
M 1r~ in
k in/hr
1,1111 fe/sec
Ar ft3/sec ,`,1{1111UI�n�P
N 4 felsec `.�Q,,,( A CARD��Pc�u�
4 E§Sip 0,° a�
W fe? QQ4 '•9
040501
34638.00 fe
-.7►1� V
9,161.00 fe FN(a•
80,823.00 fe ,'�'�,� VicI .i. ��•�••
71662.00 fe �'llllllll��,,
71,998.00 fe OK
Mandarin fine sand
1.48 in/hr
33.92 fmsl
4.00 days OK
3.00 :1 OK Id0
35.00 fmsl 'tsa^^
36.00 fmsl
6,705.00 fe
37.00 fmsl
.0It
EGEIVE
63.00 ft
5,800.00 fe
APR 2 9 2016
BY:
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & II. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWQ)
Additional Information
Maximum runoff to each inlet to the basin?
1i *e actin
Length of vegetative filter for overflow
NA ft
OK
Distance to structure
>15 ft
OK
Distance from surface waters
>50 ft
OK
Distance from water supply well(s)
>100 ft
OK
Separation from impervious soil layer
>1 ft
OK SF,�p�,gpq
Naturally occuring soil above shwt
0.75 ft
Bottom covered with 4-in of clean sand?
Y (Y or N)
OK
Proposed drainage easement provided?
—A(Y or N)
Capures all runoff at ultimate build -out?
Y (Y or N)
OK
Bypass provided for larger storms?
Y (Y or N)
OK
Pretreatment device provided
Wet Pond
RECEIVED
APR Z 9 2016
BY: -
Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. ii II. Design Summary, Page 2 of 2

A
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
I. PROJECT INFORMATION
Project name
Surf City K-8 School
Contact name
Robert Balland, PE
Phone number
910.791.6707
Date
04.27.16
Drainage area number
3
II. DESIGN INFORMATION
The purpose of the LS-VFS
SW Rule: 10-year drawdown from Wet Pond
Stormwater enters LS-VFS from
A BMP
Type of VFS
Engineered filter strip (graded & sodded, slope < 8%)
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS 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, 10-yr storm
Peak flow from the 10-yr storm
Design storm
Maximum amount of flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any 'Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP
Peak discharge from the BMP during the design storm
Peak discharge from the BMP during the 10-year storm
Maximum capacity of a 100-foot long LS-VFS
Peak flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
fe
Do not complete this section of the form.
ft
Do not complete this section of the form.
%
Do not complete this section of the form.
Do not complete this section of the form.
ds
Do not complete this section of the form.
min
Do not complete this section of the form.
in/hr
Do not complete this section of the form.
cis
Do not complete this section of the form.
lu-year storm
ds Do not complete this section of the form.
(Y or N) Do not complete this section of the form.
Wet detention pond
0 ds
8.26 cfs
10 ds
8.26 cis
N (Y or N)
9 ECEIVE
APR 2 9 2016
BY:
JA rCAFjb�
moo; oFEssio -.,!ti -;
o
AL =
040501
�,,,-1.li
�!�GINEE -EL J
Form SW401 - LS-VFS - 29June2012 - Rev.10 page 1 of 3

LS-VFS Design
Forebay surface area
sq ft
Depth of forebay at stormwater entry point
in
Depth of forebay at stormwater exit point
in
Feet of level lip needed per cis
10
fycfs
Computed minimum length of the level lip needed
63
It
Length of level lip provided
90
It
Width of VFS
50
It
Elevation at downslope base of level lip
30.05
fmsl
Elevation at the end of the VFS that is farthest from the LS
29.25
fmsl
Slope (from level lip to the end of the VFS)
1.60
%
Are any draws present in the VFS?
N
(Y or N)
Is then: a collector swale at the end of the VFS?
N
(Y or N)
Bypass System Design (if applicable)
Is a bypass system provided?
N (Y or N)
Is there an engineered flow splitting device?
(Y or N)
Dimensions of the channel (see diagram below):
M
It
B
ft
W
ft
y (flow depth for 10-year storm)
ft
freeboard (during the 10-year storm)
It
Peak velocity in the channel during the 10-yr storm
fusee
Channel lining material
Pick one:
Does the bypass discharge through a wetland?
(Y or N)
Does the channel enter the stream at an angle?
(Y or N)
Explanation of any "Other" responses above
M
W
OK
the
y Cdiuug the 10 r stotxnj ) 1
A3
RECEIVED
APR 2 9 20f6
BY:_
Form SW401 I-S-VFS - 29June2012 Rev.10 page 2 of 3

III. REQUIRED ITEMS CHECKLIST
EDIT 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.
Requried Item:
Initials Page or plan sheet number and any notes:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build -out,
Off drainage (if applicable),
em
-site
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
— 2
(AA
C ,
High flow bypass system,
One foot topo lines between the level lip and top of stream bank,
C' r%• �j
Proposed drainage easement, and
Design at ultimate build -out.
3. Section view of the level spreader (1' = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
�
C-
Upslope channel, and
Downslope filter fabric.
4. Plan details of the flow splitting device and supporting calculations (if applicable).
5. A construction sequence that shows how the level spreader will be protected from
,
sediment until the entire drainage area is stabilized.
6. If a non -engineered VFS is being used, then provide a photograph of the VFS showing
)AA
that no draws are present.
7. The supporting calculations.
l'^
8. A copy of the signed and notarized operation and maintenance (O&M) agreement.
nECE1VE
f APR 2 9 2016
BY -
Form SW401 - LS-VFS - 29June2012 - Rev.10 page 3 of 3

5�,�CT1�o� 410
HCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
I. PROJECT INFORMATION
Project name
Contact name
Phone number
Date
Drainage area number
Surf City K-8 School
Robert Balland, PE
910.791.6707
04.27.16
4
II. DESIGN INFORMATION
The purpose of the LS-VFS
SW Rule: 10-year drawdown from Wet Pond
Stormwater enters LS-VFS from
A BMP
Type of VFS
Engineered filter strip (graded & sodded, slope < 8%)
Explanation of any "Other responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area
fe
Do not complete this section of the form.
Impervious surface area
fe
Do not complete this section of the form.
Percent impervious
%
Do not complete this section of the form.
Rational C coefficient
Do not complete this section of the form.
Peak flow from the 1 in/hr storm
ds
Do not complete this section of the form.
Time of concentration
min
Do not complete this section of the form.
Rainfall intensity, 10-yr storm
inihr
Do not complete this section of the form.
Peak flow from the 10-yr storm
ds
Do not complete this section of the form.
Design storm
10-year storm
Maximum amount of flow directed to the LS-VFS
ds
Do not complete this section of the form.
Is a flow bypass system going to be used?
(Y or N)
Do not complete this section of the form.
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP Wet detention pond
Peak discharge from the BMP during the design storm 0 cfs
Peak discharge from the BMP during the 10-year storm 6.14 ds
Maximum capacity of a 100-foot long LS-VFS 10 ds
Peak flow directed to the LS-VFS 6.14 cfs
Is a flow bypass system going to be used? N (Y or N)
Explanation of any 'Other" responses above
F—(;EI F—
APR 2 9 2010
BY:
.�`��'(�H �CARp
es
• f
•
0 0501
s; r4
• IN -GIN
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�•�
���gN�Elt J" F; %
#lotsI11110
Form SW401 LS-VFS - 29June2012 - Rev.10 page 1 of 3

LS-VFS Design
Forebay surface area
Depth of forebay at stormwater entry point
Depth of forebay at stormwater exit point
Feet of level lip needed per cis
Computed minimum length of the level lip needed
Lenqth of level lip provided
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
sq ft
in
in
10
Weis;
61
It
70
It
50
ft
34.00
fmsl
33.60
fmsl
0.60
%
N
(Y or N) OK
N
(Y or N)
N (Y or N)
(Y or N)
ft
ft
ft
ft
fUsec
Pick one:
W
(Y or N)
(Y or N)
fieetmaid [ruin the l
y lduuvig the I0 .rr stui7v7
1--------- 1
kl M
i
ECEIVE
APR 2 9 2016
BY:
Form SW401 - LS-VFS - 29June2012 - Rev.10 page 2 of 3

Jill. REQUIRED ITEMS CHECKLIST
EDIT 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.
Requried Item:
1. Plans (1' - 50' or larger) of the entire site showing:
- Design at ultimate build -out,
Off -site drainage (d applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
- High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
2. Plan details 0" = 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,
- Proposed drainage easement, and
Design at ultimate build -out.
3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downslope filter fabric.
4. Plan details of the flow splitting device and supporting calculations (if applicable).
5. A construction sequence that shows how the level spreader will be protected from
sediment until the entire drainage area is stabilized.
Initials
0
Page or plan sheet number and any notes:
Ex IT` 1
C-3.to - C-3•�g
1 P C-1. L
C -1• 3
04 C'04•7j
u1 1-
6. If a non -engineered VFS is being used, then provide a photograph of the VFS showing IN IA -
that no draws are present.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance. (0&M) agreement.
C-3�ot c- 3.03
ECE.IVE
APR 2 9 2016
BY:
Form SW401 LS-VFS - 29June2012 - Rev.10 page 3 of 3

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
STORMWATER MANAGEMENT & EROSION CONTROL
NARRATIVE
Prepared for:
PENDER COUNTY SCHOOLS
925 PENDERLEA HIGHWAY
BURGAW, NC 28425
Prepared by:
PARA1\4C)"LJWTE
E " G ! " E: E St N G. i N G
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
NC License »: C-2846
yam : •".. •• J
Project #15348.PE
April, 2016
��4y.
�¢'1j0.
rataiaes•ea:A
ECEIVE
APR 2 9 2016
gY;:SW 8I (00+10

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
Project #15348.PE
Table of Contents
Design Narrative
Proposed Improvements
Design Method
Calculation Summary
Maintenance
Erosion and Sedimentation Control Specification
Soils Map
Reference Data
USGS Map
Erosion Control Calculations
Stormwater Calculations Overall
Stormwater Calculations Wet Ponds
Stormwater Calculations Infiltration Basins
Stormwater Calculations Stormwater Pumps
Stormwater Calculations Level Spreader
Soils Report (By Others)
Page

SURF CITY K-8 SCHOOL
TOWN OF SURF CITY
PENDER COUNTY
NORTH CAROLINA
Project #15348.PE
DESIGN NARRATIVE
Pender County Schools is proposing to construct a new K-8 School on a 99.22-acre site off of
Shepards Road in the Town of Surf City in Pender County, NC. The latitude and longitude of
the property are 34' 27' 46" N, 77' 34' 28" W. The site is further identified by Pender County
Parcel Identification Number#: 4226-92-2047-0000.
The existing site is relatively flat with wetland areas and wooded ground cover. The existing
site is split into two drainage areas; the southern portion ultimately drains to Becky's Creek and
the northern portion ultimately drains to County Line Branch. Both Becky's Creek and County
Line Branch have a stream classification of SA, HQW. The site discharge points are greater than
575 feet from the HQW. Soils consist mainly of Leon fine sand(LnA) (HSG A/D), Mandarin fine
sand (Ma) (HSG B/D) and Murville muck (Mu) (HSG A/D), according to the NRCS soil survey.
The seasonal high water table for the proposed wet ponds were determined using the
parameters described on pages 10-9 and 10-10 of the BMP manual; therefore, using good
engineering judgement by field survey, inspection, and discussion with client on existing
conditions of the outfall; lead to the setting of each respective outfall elevation. The elevation
for the permanent pool and seasonal high water table was determined as well by observing the
wetlands throughout the area and the surveyed elevation of the wetland areas.
PROPOSED IMPROVEMENTS
The applicant is proposing to build a K-8 School along with associated parking, access roads,
athletic fields, pump station and stormwater management system. Runoff resulting from
impervious surfaces will be collected by a combination of overland flow, swales, and an
underground (piped) storm drainage system. The conveyance system will then be discharged
to one of four (4) wet detention ponds designed for 90% TSS removal.
Due to the site's discharge points being within 1/2 mile of SA waters, each wet pond's water
quality volume will discharge to one of three (3) infiltration basins. Wet Pond 1 and Wet Pond
2 will discharge by gravity to Infiltration Basin 1 and Infiltration Basin. 2 respectively. Wet Pond
3 and Wet Pond 4 have been designed to have their water quality volumes pumped to
Infiltration Basin 3 due to the Site's constraints of suitable areas for infiltration per the NCDENR
Stormwater Best Management Practices Manual requirements relative to the existing
topography.

The ponds have been designed to meet NCDENR requirements, which include a forebay and a
drawdown orifice at permanent pool. Stormwater from greater storm events will bypass the
outlet that flows to the respective infiltration basin through either an outlet structure and
culvert or rip -rap spillway. The ponds have all been designed to have an emergency spillway
as well.
The infiltration basins have been designed to meet NCDENR requirements for an infiltration
basin in series. Pretreatment is provided by the wet detention ponds, the bottom has been
designed to be at least 1' above seasonal high water table (SHWT) elevation, and an emergency
spillway has been provided. A bottom surface area has been provided to infiltrate the water
quality volume at 1/2 the measured infiltration rate within five (5) days. Wet Pond 1 and Wet
Pond 2 have been designed to have a water quality volume that is greater than two times the
required volume to waive the need for a level spreader and vegetated filter strip in accordance
with the NCAC 2H.1008(h) alternative design criteria. Wet Pond 3 and Wet Pond 4 have been
designed to have a water quality volume that is greater than required but not in accordance
with the alternative design. Therefore, both Wet Pond 3 and Wet Pond 4 have a proposed level
spreader and vegetated filter strip. As mentioned before, all wet ponds contain a bypass
structure/spillway.
The stormwater pumps (Wet Pond 3 and Wet Pond 4) have been designed to pump at an
operating point that is less than the drawdown rate for the wet pond orifice. The volume
pumped during the storm event is less than 25% of the required volume, and the pump on
elevation is greater than 4" above the pump off elevation.
During construction, sediment will be controlled by temporary silt fence, temporary diversion
ditches, temporary inlet protection, culvert crossings, and temporary construction entrances.
The wet ponds will serve as temporary sediment/skimmer basins.
Please find all reference material and calculations in the following pages of this report. Note
that some calculations have also been located on the plans for easy reference during
construction.
DESIGN METHOD
Hydrologic calculations have been performed utilizing HydroCAD version 10.0 software which
employs the USDA SCS Method. The Type -III 24-hour storm rainfall depth (precipitation data)
has been taken from the NOAA Atlas 14 Precipitation Frequency Data Server (PFDS) with the
depth selected falling within the 90% confidence interval. Curve Number (CN) and Time of
Concentration (TOC) calculations have been performed in accordance with the USDA TR-55
manual, with a minimum TOC of 5 minutes.
Hydrologic Soil Group Classifications have been taken from the USDA Web Soil Survey.

Storm conveyance calculations have been performed utilizing the Rational Method within
Carlson Hydrology 2016 which employs the FHWA Method for HGL computations.
MAINTENANCE
Contractors shall be responsible for periodic inspection and maintenance of all indicated
erosion control devices in accordance with the plans and specifications. In addition, inspection
and any necessary maintenance will be required immediately following any significant storm
event. Any erosion control measure that fails to function as intended shall be repaired
immediately. Upon completion of construction and the establishment of stabilized ground
cover, the property owner shall be responsible for any on going site maintenance.

EROSION AND SEDIMENTATION CONTROL SPECIFICATION
PART 1-GENERAL
1.1 RELATED DOCUMENT
A. Drawings and general provisions of the Contract, including General and Supplementary
Conditions and Division 1 Specification Sections, apply to this Section.
1.2 WORK INCLUDED
A. Contractor shall take every reasonable precaution throughout construction to prevent the
erosion of soil and the sedimentation of streams, lakes, reservoirs, other water impoundments,
ground surfaces, or other property as required by State and Local regulations.
B. Contractor shall, upon suspension or completion of land -disturbing activities, provide
protection covering for disturbed areas. Permanent vegetation shall be established at the
earliest practicable time. Temporary and permanent erosion control measures shall be
coordinated to assure economical, effective, and continuous erosion and sediment control
throughout the construction and post construction period.
1.3 RELATED SECTIONS
A. Related Sections - The following Sections contain requirements that relate to this Section:
1. 01011- Existing Underground Utilities
2. 01015 - Special Conditions for this Contract
3. 01070 - Shop Drawings, Project Data & Samples
4. 02200 - Earthwork, Excavation Trenching, and Backfilling
5. 02230 - Site Clearing
6. 02240 - Dewatering
7. 02485 - Seeding General Areas
1.4 REGULATORY REQUIREMENTS
A. Contractor shall be responsible for prevention of damage to properties outside the construction
limits from siltation due to construction of the project. The Contractor will assume all
responsibilities to the affected property owners for correction of damages that may occur.
Erosion control measures shall be performed by the Contractor, conforming to the requirements
of, and in accordance with plans approved by applicable state and local agencies and as per the
erosion control portion of the construction drawings and these specifications. The Contractor
shall not allow mud and debris to accumulate in the streets. Should the Contractor pump water
from trenches during construction, appropriate siltation preventative measures shall be taken
prior to discharge of pumped water into any storm drain or stream.

1/11/2016 Precipitadon Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Hampstead, North Carolina, US"'
f .i Latitude: 34.46280, Longitude: 77.5744°
r
[� +_-` .•,- Elevation: 36 ft
• source: Google Maps
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bannin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring. Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)'
Duration
Average recurrence interval (years)
1
2
5
10
25
50
1 700
00
200
500
1000
0.500
0.594
0,695
0.774
0.873
05949
1.03
1.70
12D
1.28
5-mrn
(0.464-0.542)
(0.550-0.643)
(0.642-0.751)
(0.713-0.836)
(0.801-0.942)
(0.867-1.02)
(0.931-1.1 1)
(0.995-1.19)
(1.07-1.30)
(1.14-1.39)
0.799
0.950
1.17
124
1,39
1.51
1.63
1,75
1.90
2.02
10{rtln
(0.74D-0.865)
0 999 7
(0.880-1.03)j
F-1.79
1 AlF
1 (1.14-1.34) 11
1-.56--JF
(1.28-1.50)
1.76
(1.38-1.63)
1.91
(1.48-1.76)
2.06
(1.58-1.89)
220
(1.70-2.06)
2 39
(1.79-2.19)
2S4
75{rtin
(0 .925-1.08)
(1.11-1 29) 11
(1.44-1.69) 11
(1.62-1.90)
(1.75-2.06)
(1.87-2.22)
(1.99-2.38)
(2.14-2.59)
(2.25-2.75)
1.37
1.65
2.00
2Z7
2.61
2.88
3.16
3A3
3 81
4.11
30�rtin
(1.27-1A8) 11
(1.53-1.79)
(1.85-2.16)
1 (2.09-245) 11
(2.40-2.82)
(2.63-3.11)
(2.87-3A0)
(3.10-3.71)
(3A0-4.13)
(3.64-4A6)
1.71
2.07
2S6
2.95
3A8
3.90
435
4.87
5A6
6A0
60�rttn
(1.58-1.85) 11
(1.92-224)
(2.37 2.77)
(2.72-3.19)
(3.19-3.75)
(3.57-4.21)
(3.95-4.69)
(4.34-5.20)
(4.88-5.92)
(5.31-6.51)
2.08
2.54
323
3.79
4.60
5Z8
6.02
6.82
7 98
8,97
2�1r
(1.92-226)
(2.34-2.76)
(2.97-3.51
(3A8-4.13
�������
4.20-5.00)
(4.80-5.73)
(5.43-6.54)
(6.11-7.40
7.08-8.69)
(7.89-9.79
3a1r
2.24
(2 06-2A5)
2.73
(2.52-3.00)
3A9
(3.21 3.82 j
4.13
( 3.78 4.52)
558
(4.62-5.54)
5,90
(5.33-6A3 )
6,80
(6.09-7.4)
�
7.79
(S.o2 8 49)
929
(8.14-1C.1)
��
10.6
(9.18-11.6)
2.74
3535
4Z9
5,08
627
7.30
T 8A4
9,71
T-11.671
13.3
6a1r
(2.51-3.02)
1 (3.07-3.69) 1
(4.63-5.60) 11
(5.67-6.89)
(6.55-8.01)
(7.51-9.25)
(8.55-10.6)
(10.1-12.8)
(11A-14.6)
3Z3
3.94
5.08
6,06
7.53
8,81
10.3
71.9
14A
16.6
12-I1r
(2.93-3.60)
1 (3.58-4.39) 11
(4.60-5.65) 11
(5.46-6.73) 11
(6.73-8.33)
(7.82-9.73)
(9.02-11.3)
(10.3-13.1)
(12.3-15.9)
(14.0-18.3)
24fir
3.5
4S1
5.84
6.99
8.73 11
10-3 1
F 12.0
33A
66.9
99A
(3. 9)
(4.15-4.97)
(5.36-6.42)
(6.38-7.66)
1 (7.89-9.55)
(9.19-11.2)
(10.6-13.1)
(122-15.3)
(14A-18.6)
(16A-21.6)
4.34
525
6.74
8.02
9.98
11.7
13.6
15.8
19.1
22A
2�ay
(3.98-4.77)
(4.82-5.78)
(8.16-7.42)
(7.30-8.82)
(9.01-11.0)
(10.5-12.9)
(12.0-15.0)
(13.8.17.5)
(16.3-21.3)
(18A-24.6).
4,59
5S5
7.09
8.39
10A
12.1
13.9
16.0
79.3
22.1
3�ay
(4.22-5.04)
(5.10-6.10
(6.49-7.78)
��������
(7.66-9.21)
(9.37-11.4)
(10.8-13.2)
(12.4-15.3)
(14.1-17.7
16.6-21.4)
(18.7-24.7
4.85
5.86
7A4
8.77
10.7
12A
14.3
16.3
19.5
22Z
4-day
(4A6-5.31) 11
(5.39-6.42)
(6.82-8.15)
1 (9.73-11.7)
(11.2-13.6)
(12.7-15.6) 11
(14A-17.9)
(16.8-21.6)
(18.9-24.8)
5.59
6.74
8A7
9.91
12.0
13.8
75,7
77.7
20.7
23.3
'-day
(5.17-6.08)
624
(6.23-7.32)
7A7
(7.82-9.20)
9Z6
(9.12-10.8)
10.7
(11.0-13.0)
12.9
(12.5-14.9)
14.7
(14.1-17.1)
16.6
(15.8-19.3)
18.7
(18.2-22.8)
21.7
( 20.1-25.7)
242
10�1ay
(5.78-6.77) 11
(6.93-8.12)
1 (8.57-10.0) 1
1 (11.8-14.0)
(13A-15.9)
(15.0-18.1)
(16.7-20.4)
(19.1-23.8)
(21.0-26.7)
827
9.86
12A
13.8
16,3
18A
20.5
22.9
26.1
28.8
20{lay
(7.73-8.89) 11
(9,20-10.6)
1 (11.2-12.9) 11
(12.8-14.8) 11
(15.0-17.5)
(lB.9-19.7)
(18.7-22.1)
(20.6-24.7)
(23.2-28.4)
(25.3-31.5)
10.1
12A
14A
16A
19.7
27.3
23.5
25.8
28.9
31A
30�1ay
(9.51-10.8)
(11.3-12.8)
(13.6-15.4) 11
(15.4-17.5) 11
(17.8-20.4)
(19.7-22.7)
(21.7-25.1)
(23.6-27.7)
(26.2-31.3)
(28.2-34.1)
12.7
15A
17.9
202
23A
26.0
28,7
31.5
35.3
38.2
45�ay
(11.9-13.6)
(14.1.1B.1)
(16.8-19.1) 11
(18.9-21.6) 11
(21.8-25.1)
(24.1-27.9)
(26.5-30.8)
(28.8-33.8)
(31.9-38.1)
(34.3-41.6)
15A
18.1
23.8
272
299
32.6
35.3
38.9
41721.3
EO�ay
(145 16.3)
(7
0.2
4 25
25-28.
2
334.7)
323
37-41.8)
.9 45.0) I
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers In parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency
estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at
upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Too
PF graphical
httpJ/hdsc.nws.rioaa.gov/hdscfpfds/pfds_prin4xgeJitm l?Iat=34.4628&Ion=-77.5744&data=depth&units=english&series=pds 114

U.S.DEPARTAHMOPTHEUnIMOR
GBOE40GICAL SURVEY
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HOLLY RIDGE QUADRANGLE
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7.5-MM SEW
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SCALE 1:24 000
HOLLY RIDGE, SIC
2013
Ll

0
3D
I o .�
I
Outlet W = Do + 0.41-a
pipe i
diameter (Do)
Tai r 5Do
20
17 —
2 13
4V BO
v
70
_1.MMMMMMMMMMA:p
10 11
120 I 50 3 100
FES-35 Discharge (ft /sec)
FES-31 FES-11 FES-1
FES-24
Curves may not be extrapolated.
FLARED END SECTIONS
SURF CITY K-8 SCHOOL
15348.PE
04.27.16
Figure 8.06b Design of outlet protection from a round pipe flowing full, maximum tailwater condition (T..v >_ 0.5 diameter).
FES-1
FES-11
FES-24
FES-31
FES-35
Do = 36"
Do = 48"
Do = 24"
Do = 30"
Do = 30"
3Do=9'
3Do=12'
3Do=6'
31)o=7.5'
3Do=7.5'
La=13'
La=17'
La=10'
La=12'
La=12'
W=9'
W=12'
W=6'
W=7.5'
W=7.5'
N
U)
CL
M
_a
1 a:
0
8.06.4
Rev. 12/93

Project Name: Surf City K-8
Client: LS3P
Project Number: 15348.PE
Prepared By: DJF
Date: 4/25/16
Wet Detention Basin / Infiltration Basin in Series
1 yr. 24 hour Pre / Post: Simple Method
1
2
3
4
Rainfall Depth (1yr. 24hr.) [in.] =
3.5
3.5
3.5
3.5
Drainage Area to System [Ac.] =
10.82
4.83
9.90
4.52
Pre Development:
Impv. Area (PRE) [Ac.]=
0.00
0.00
0.00
0.00
% Impervious (PRE) =
0.00
0.00
0.00
0.00
Runoff Coefficient (PRE) (Rv) =
0.050
0.050
0.050
0.050
Pre Volume [cf] =
6,871
3,068
6,292
2,869
Post Development:
Impv. Area (POST) [Ac.]=
5.67
2.28
3.51
2.75
% Impervious (POST) =
52.45
47.12
35.46
61.00
Runoff Coefficient (POST) (Rv) =
0.522
0.474
0.369
0.599
Post Volume [cf] =
71,734
29,088
46,454
34,369
Pre/Post [cf] =
64,864
26,020
40,163
31,500

Project Name: Surf City K-8
Client:
LS3P
Project Number:
15348.PE
Prepared By:
DJF
Date:
4125/16
Average Depth Calculation: (Option 2 per Errata)
Pond #1
ABottom shelf =
68,435
sf
ABottom Pond =
37,450
sf
APerm Pool =
79,800
sf
Depth =
4.00
ft
day =
3.6
ft
Pond #2
ABottom Shelf =
9,020
sf
ABottom Pond =
3,690
sf
APerm Pool =
16,580
sf
Depth =
5.00
ft
day =
3.9
ft
Pond #3
ABottom Shelf =
15,645
sf
ABottom Pond =
6,625
sf
APerm Pool =
19,660
sf
Depth =
4.00
ft
davg =
3.3
ft
Pond #4
ABottom Shelf =
21,660
sf
ABottom Pond =
7,000
sf
APerm Pool =
28,320
sf
Depth =
4.00
ft
day =
3.1
ft
P'.A M.1NT`E
4 M c; 1" a r

Surf City K-8 : Wet Pond #1
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20 % of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3:1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 10.816 ACRE Value from CAD
Impervious Drainage Area 5.673 ACRE Value from CAD
o Impervious Cover -(Impervious Drainage
Impervious Cover 52.45 /o Area)/(Total Drainage Area)*100%
Elevation of Permanent Pool Surface
35.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
(Bottom Elevation)=(Permanent Pool Surface
Elevation of Wet Detention Pond Bottom
30.0
FT
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
680
FT
Value from CAD
Approximate Pond Width
117
FT
Value from CAD
Len th:Width Ratio
5.8:1
Ratio=(Length)/(Width):l
Required SAIDA Ratio for 90% TSS Removal 5.25 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 24,734 SF Required Surface Area=(Required SA/DA
Ratio) *(Total Drainage Area)
Provided Permanent Pool Surface Area 79,800 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.522 MIN Rv=0.05+0.009*(010 Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 30,743 CF 1.5" Runoff Volume=l.5 inch*Rv*l foot/12
inch*(Total Drainage Area)
Required Runoff Volume (Pre/Post Volume
difference of 1-Year storm)
2X Required Runoff Volume (Pre/Post Volume
difference of 1-Year storm) [Provided to remove
veg filter and level spreader for Infilration Basin in
series]
64,864 CF [see simple method calculations]
129,728 CF [simple method calculation]*2
Volume Below Permanent Pool 303,120 CF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 432,848 CF Total Volume to be Controlled=(Volume Below
Permanent Pool)+(2X Required Runoff Volume)
Storage Elevation at Required Volume 36.53 FT Value is interpolation based upon stage -storage
values. See staae-storaae calculations
Step 3: Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume provideo
Total Pond Volume 303,120 CF Value from stage -storage calculations
Required Total Forebay Volume 54,562 CF Forebay Volume= Total Pond Volume *18%
Provided Total Forebay Volume 62,480 CF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 20.6% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4A: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
6.00
IN
Value chosen by designer
Elevation of Outlet Structure
36.53
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.53
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.51
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.68
CFS
Q=Cd*(Pi)*[(Diameter of Orifice) *(1fill 2
in)r2/4*[2*32.2*(Averge Head)]"12
Drawdown Time for Req'd WQV
2.22
DAYS
(Drawdown Time)=(Required Runoff Volume)/Q*(1
Step 4B: Verify that time required to drawdown the provided runoff volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
6.00
IN
Value chosen by designer
Elevation of Outlet Structure
36.60
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.60
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice) [(Storage
Average Elevation Head Above Orfce
0.53
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.69
CFS
Q=Cd*(Pi)*[(Diameter of Orifice)*(1 W12
in)j"2/4* *32.2*(Averqe Head)]412
Drawdown Time for Provided WQV
2.28
DAYS
(Drawdown Time)=(Provided Runoff Volume)/Q*(1

Surf City K-8 - Wet Pond #1
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
35.00
79,800
0
0 «Permanent Pool
36.00
85,655
82,728
82,728
37.00
91,630
88,643
171,370
38.00
97,710
94,670
266,040
38.50
100,795
49,626
315,666
Stage/Storage Main Pond (Not Including Forebays)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
27.0
27,135
-
- --Sediment Storage
28.0
30,385
-
-
29.0
33,820
-
30.0
37,450
0
0 +Bottom Elev.
31.0
41,230
39,340
39,340
32.0
45,160
43,195
82,535
33.0
49,235
47,198
129,733
34.0
54,655
51,945
181,678
35.0
63,270
58,963
240,640 Permanent Pool
Stage/Storage Total Pond (Including Forebay)
Main Pond
Cumulative
Volume
Forebay #1
Forebay #2
Forebay #3
Volume, S
Contour
(CF)
Volume (CF)
Volume (CF)
Volume (CF)
(CF)
27.0
0
0
0
0
0
28.0
0
1,530
0
875
2,405
29.0
0
3,685
0
2,158
5,843
30.0
0
6,575
0
3,920
10,495
31.0
39,340
10,320
0
6,233
55,893
32.0
82,535
15,050
413
9,163
107,160
33.0
129,733
20,895
1,118
12,780
164,525
34.0
181,678
27,985
2,188
17,153
229,003
35.0
240,640
36,445
3,690
22,345
303,120
Forebay #1
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
780
-
- -.Sediment Storage
27.0
1,245
0
0 -Bottom Elev.
28.0
1,815
1,530
1,530
29.0
2,495
2,155
3,685
30.0
3,285
2,890
6,575
31.0
4,205
3,745
10,320
32.0
5,255
4,730
15,050
33.0
6,435
5,845
20,895
34.0
7,745
7,090
27,985
35.0
9,175
8,460
36,445 •forebay Volume

Surf City K-8 - Wet Pond #1
Stage -Storage Calculations for Proposed Wet Detention Pond
Forebay #2
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
30.0
110
-
-—Sediment
Storage
31.0
285
0
0
Bottom Elev.
32.0
540
413
413
33.0
870
705
1,118
34.0
1,270
1,070
2,188
35.0
1,735
1,503
3,690
«forebayVolume
Forebay #3
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
395
-
-
-Sediment Storage
27.0
690
0
0
Bottom Elev.
28.0
1,060
875
875
29.0
1,505
1,283
2,158
30.0
2,020
1,763
3,920
31.0
2,605
2,313
6,233
32.0
3,255
2,930
9,163
33.0
3,980
3,618
12,780
34.0
4,765
4,373
17,153
35.0
5,620
5,193
22,345
�Forebay Volume

Project Name: Surf City K-8 School -- --T _--
PA TEE
Client: Surf City
County Schools RA M au 1 �)
Project Number: 15348.PE ex I f Ft I " c IJ. 1 � C�
Prepared By: DJF
Date: 4/26/16
Forebay Percentage Calculation: (Per NCDENR SWM BMP Manual Section 10.3.3)
Overall BMP (WET POND #1)
Drainage Area = 10.816 Acres
Total Forebay Vol. 62,480 cf
Forebay #1
Drainage Area =
6.270 Acres
58% of total drainage area
Forebay Volume =
36,445 cf
58% of total forebay volume
Forebay #2
Drainage Area =
0.650 Acres
6% of total drainage area
Forebay Volume
3,690 cf
6% of total forebay volume
Forebay #3
Drainage Area =
3.896 Acres
36% of total drainage area
Forebay Volume =
22,345 cf
36% of total forebay volume

Surf City K-8 - Wet Pond #2
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet, a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 4.830 ACRE Value from CAD
Impervious Drainage Area 2.276 ACRE Value from CAD
Impervious Cover 47.12% Impervious Cover --(Impervious Drainage
Area)/(Total Drainage Area) *100%
Elevation of Permanent Pool Surface
33.00
FT
Value selected by designer
Depth of Permanent Pool
6.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
27.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
FT
Value from CAD
Approximate Pond Width
65
FT
Value from CAD
Len thMidth Ratio
3.9:1
Ratio= Len h /(Wdth):1
Required SAM Ratio for 90% TSS Removal 4.07 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 8,562 SF Required Surface Area=(Required SA/DARatio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 16,580 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.474 IN/IN Rv=;0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 12,466 CIF 1.5"Runoff V61ume=1.5 inch*Rv*1 foot/12
inch*(Total Drainage Area)
Required Runoff Volume (Pre/Post Volume
difference of 1-Year storm)
2X Required Runoff Volume (Pre/Post Volume
difference of 1-Year storm) [Provided to remove
veg filter and level spreader for Infiltration Basin in
series]
26,020 CIF [see simple method calculations]
52,040 CIF (simple method calculation1*2
Volume Below Permanent Pool 52,630 CIF Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled 104,670 CIF Total Volume to be Controlled=(Volume Below
Permanent Pool)+(2X Runoff Volume)
Storage Elevation at Required Volume 35.55 FT Value is interpolation based upon stage -storage
values. See stage-storaoe calculations
Step 3. Calculate the required forebay volume (18-22% of total pond volume) and compare to the forebay volume providea
Total Pond Volume 52,630 CIF Value from stage -storage calculations
Required Total Forebay Volume 9,473 CIF Forebay Volume= otal Pond Volume *18%
Provided Total Forebay Volume 10,588 CIF Value from stage -storage calculations
(Provided Forebav Volume)/(Total Pond
Provided Forebay Voiume:Totai 'rood Volume 20.i % Volume)*100%

Step 4: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.55
FT
Value chosen by designer
(Total Elevation Head Above Orifice)=(Weir
Total Elevation Head Above Orifice
2.55
FT
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orfice)=[(Storage
Elevation at Required Volume)+(Elevation of
Average Elevation Head Above Orifice
0.85
FT
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.22
CFS
Q=Cd*(Pi)*[(Diameter of Orifice)*(1 ft/12
in)7A91,d*r9*49 9*/dvama 14inarMA119
Drawdown Time for Re 'd WQV 2.76 DAYS (Drawdown Time)=(Required Runoff Vo1ume)/Q*(1
4 rlav/RRdnn 0,,nnr/el
Diameter of Proposed Low -flow Orifice
3.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.55
FT
Value chosen by designer
(Total Elevation Head Above Orifice)=(Weir
Total Elevation Head Above Orifice
2.55
FT
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=[(Storage
Average Elevation Head Above Orifice
0.85
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
0.22
US
Q=Cd*(Pi)*[(Diameter of Orifice) *(I ft/12
in).r2/4*[2*32.2*(Averge Head)P1/2
(Drawdown Time)=(Provided Runoff Vo1ume)/Q*(1
Drawdown Time for Provided WQV
2.76
DAYS

Surf City K-8 - Wet Pond #2
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
33.00
16,580
0
0 rPermanent Pool
34.00
19,420
18,000
18,000
35.00
22,380
20,900
38,900
36.00
25,"0
23,910
62,810
37.00
28,625
27,033
89,843
Stage/Storage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
26.0
2,885
0
0 --Sediment Storage
27.0
3,690
0
0 -Bottom Elev.
28.0
4,580
4,135
4,135
29.0
6,680
5,630
9,765
30.0
8,435
7,558
17,323
31.0
10,350
9,393
26,715
32.0
12,450
11,400
38,115
33.0
16,580
14,515
52,630 -Permanent Pool
Forebay
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.6
570
-Sediment Storage
29.0
1,135
0
0 •-Bottom Elev.
30.0
1,835
1,485
1,485
31.0
2,600
2,218
3,703
32.0
3,430
3,015
6,718
33.0
4,310
3,870
10,588 rForebay Volume

Surf City K-8 - Wet Pond #3
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3:1.
Step 1: Determine the surface area required for 90% TSS removal
Post -Development Conditions
Total Drainage Area 9.904 ACRE Value from CAD
Impervious Drainage Area 3.512 ACRE Value from CAD
Impervious Cover 35.46% Impervious Cover=(Impervious Drainage
Area)/(Total Drainage Area) 100%
Elevation of Permanent Pool Surface
30.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
(Bottom Elevation)=(Permanent Pool Surface
Elevation of Wet Detention Pond Bottom
25.0
FT
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
255
FT
Value from CAD
Approximate Pond Width
77
FT
Value from CAD
Len th:Width Ratio
3.3:1
Ratio= Len th / idth :1
Required SAIDA Ratio for 90% TSS Removal 3.55 Value tram chart. Reterence: "YU% I SS Hemoval
Required Permanent Pool Surface Area 15,315 SF Required Surface Area=(Required SAIDA
Ratio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 19,660 SF Interpolated value from stage -storage calculations
Step 2: Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.369 MIN Rv=0.05+0.009*(% Impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 19,909 CF 1.5" Runoff Volume=1.5 inch*Rv*1 foot/12
inch*(Total Drainage Area)
Required Runoff Volume (Pre/Post Volume
40,163 CF
[see simple method calculations]
difference of 1-Year storm)
Volume Below Permanent Pool
62,503 CF
Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled
82,411 CF
Total Volume to be Controlled=(Volume Below
Permanent Pool)+(1.5" Runoff Volume)
Storage Elevation at Required Volume
31.85 FT
Value is interpolation based upon stage -storage
values. See stage -storage calculations
Step 3: Calculate the required Forebay volume (18-22% of total pond volume) and compare to the forebay volume providea
Total Pond Volume 62,503 CF Value from stage -storage calculations
Required Total Forebay Volume 11,250 CF Forebay Volume= Total Pond Volume *18%
Provided Total Forebay Volume 12,625 CF Value from stage -storage calculations
Provided Forebay Volume:Total Pond Volume 20.2% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
4.00
IN
Value chosen by designer
Elevation of Outlet Structure
31.85
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.85
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.62
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface))/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
Varies
See HydroCAD Drawdown Calculation
[Stage/Dischrge]
Drawdown Time for 1.5-inch Runoff
3.13
DAYS
See HydroCAD Drawdown Calculation
Step 5: Verify that time required to drawdown the provided water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
4.00
IN
Value chosen by designer
Elevation of Outlet Structure
31.85
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.85
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice) [(Storage
Average Elevation Head Above Orce
0.62
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface))/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
Varies
HydroCAD Calculation
Drawdown Time for 1.5-Inch Runoff
3.13
DAYS
HydroCAD Calculation

Surf City K-8 - Wet Pond #3
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
30.00
19,660
0
0 Permanent Pool
31.00
21,795
20,728
20,728
32.00
24,000
22,898
43,625
33.00
26,260
25,130
68,755
34.00
28,575
27,418
96,173
35.00
30,950
29,763
125,935
35.50
32,160
15,778
141,713
Stage/Storage Total Pond (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
6,180
- --Sediment Storage
25.0
7,585
0
0 ••Bottom Elev.
26.0
9,185
8,385
8,385
27.0
10,995
10,090
18,475
28.0
13,055
12,025
30,500
29.0
15,645
14,350
44,850
30.0
19,660
17,653
62,503 -Permanent Pool
Forebay 01
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
24.0
590
-
- • -Sediment Storage
25.0
960
0
0 •Bottom Elev.
26.0
1,435
1,198
1,198
27.0
2,030
1,733
2,930
28.0
2,785
2,408
5,338
29.0
3,625
3,205
8,543
30.0
4,540
4,083
12,625 +forebay Volume

Surf City K-8 - Wet Pond #4
NC DENR Retention Requirements
Objective: design a wet detention basin with the following characteristics: a permanent water pool depth between 3- and
6-feet a surface area that meets TSS removal requirements (values set by NC DENR and included here), a forebay that
is approximately 20% of the total pond volume, a temporary water pool sized to detain the Initial 1.5 inch of rainfall runoff, an
outlet device that drains the temporary water pool within 2-5 days, and a length -to -width ratio of approximately 3.1.
Step 1: Determine the surface area required for 90016 TSS removal
Post -Development Conditions
Total Drainage Area 4.516 ACRE Value from CAD
Impervious Drainage Area 2.755 ACRE Value from CAD
Impervious Cover 61.00% impervious Cover --(Impervious Drainage
Area)/(Total Drainage Area)*100%
Elevation of Permanent Pool Surface
34.00
FT
Value selected by designer
Depth of Permanent Pool
5.00
FT
Value selected by designer
Elevation of Wet Detention Pond Bottom
29.0
FT
(Bottom Elevation)=(Permanent Pool Surface
Elevation) -(Depth of Permanent Pool)
Approximate Pond Length
FT
Value from CAD
Approximate Pond Width
71
FT
Value from CAD
Len h:Width Ratio
5.6:1
Rado=(Length)/(Width):1
Required SA/DA Ratio for 90% TSS Removal 7.11 Value from chart. Reference: "90% TSS Removal
Required Permanent Pool Surface Area 13,986 SF Required Surface Area=(Required SAIDA
Ratio)*(Total Drainage Area)
Provided Permanent Pool Surface Area 28,320 SF Interpolated value from stage -storage calculations
Step 2. Determine the WQV runoff elevation within the wet detention pond
Runoff Coefficient, Rv 0.599 MIN Rv=0.05+0.009*(% impervious)
1.5" Runoff Volume (Volume of Temporary Pool) 14,729 CF 1.5" Runoff Volume=l.5 inch*Rv*l 1oot/12inch*(Total Drainage Area)
Required Runoff Volume (Pre/Post Volume
31,500 CF
[see simple method calculations]
difference of 1-Year storm)
Volume Below Permanent Pool
81,905 CF
Value from stage -storage calculations (cumulative
pond volume at permanent pool elevation)
Total Volume to be Controlled
113,405 CF
Total Volume to be Controlled=(Volume Below
'
Permanent Poo) + 1.5" Runoff Volume
Storage Elevation at Required Volume
35.04 FT
Value is interpolation based upon stage -storage
—]
values. See staoe-storaae calculations
Step 3. Calculate time required forebay volume (18-22'16 of total pond volume) and compare to the forebay volume provideo
Total Pond Volume 81,905 CF Value from stage -storage calculations
Required Total Forsbay Volume 14,743 CF Forebay Volume= otal Pond Volume *18%
Provided Total Fore!Ty Volume 16,113 CF Value from sta a-stora a calculations
Provided Forebay Volume:Total Pond Volume 19.7% (Provided Forebay Volume)/(Total Pond
Volume)*100%

Step 4: Verify that time required to drawdown the required water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
6.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.04
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.04
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.35
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
Varies
See H droCAD Drawdown Calculation
Drawdown Time for 1.5-inch Runoff
3.02
DAYS
See H droCAD Drawdown Calculation
Step 5: Verify that time required to drawdown the provided water quality volume is within 2 to 5 days
Diameter of Proposed Low -flow Orifice
6.00
IN
Value chosen by designer
Elevation of Outlet Structure
35.05
FT
Value chosen by designer
Total Elevation Head Above Orifice
1.05
FT
(Total Elevation Head Above Orifice)=(Weir
Elevation) -(Elevation of Permanent Pool Surface)
(Average Elevation Head Above Orifice)=((Storage
Average Elevation Head Above Orifice
0.35
FT
Elevation at Required Volume)+(Elevation of
Permanent Pool Surface)]/3-(Storage Elevation at
Required Volume)
Cd, Coefficient of Discharge
0.60
Value chosen by designer
Q, Flowrate Through Low -flow Orifice
Varies
H droCAD Calculation
Drawdown Time for 1.5-inch Runoff
3.02
DAYS
H droCAD Calculation

Surf City K-8 - Wet Pond #4
Stage -Storage Calculations for Proposed Wet Detention Pond
Stage/Storage Above Permanent Pool (Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
34.00
28,320
0
0 permanent Pool
35.00
31,920
30,120
30,120
36.00
35,575
33,748
63,868
37.00
39,290
37,433
101,300
37.25
40,225
9,939
111,239
Stage/Storage Main Pond (Not Including Forebay)
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
5,265
-
- -Sediment Storage
29.0
7,000
0
0 +-Bottom Elev.
30.0
9,085
8,043
8,043
31.0
11,345
10,215
18,258
32.0
13,775
12,560
30,818
33.0
16,900
15,338
46,155
34.0
22,375
19,638
65,793 Permanent Pool
Stage/Storage Total Pond (Including Forebay)
Main Pond
Cumulative
Volume
Forebay
Volume, S
Contour
(CF)
Volume (CF)
(CF)
28.0
0
29.0
0
-
0
30.0
8,043
0
8,043
31.0
18,258
2,848
21,105
32.0
30,818
6,410
37,228
33.0
46,155
10,760
56,915
34.0
65,793
16,113
81,905
Forebay #1
Cumulative
Contour
Incremental
Volume, S
Contour
Area (SF)
Volume (CF)
(CF)
28.0
1,380
-
- -Sediment Storage
29.0
1,905
-
-
30.0
2,510
0
0 -Bottom Elev.
31.0
3,185
2,848
2,848
32.0
3,940
3,563
6,410
33.0
4,760
4,350
10,760
34.0
5,945
5,353
16,113 -Forebay Volume

u
mm
w

15348.PE WQV Pond Drawdown Type 111 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 2
Summary for Pond 15P: Wet Pond #3
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Outflow = 0.55 cfs @ 0.00 hrs, Volume= 39,686 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.55 cfs @ 0.00 hrs, Volume= 39,686 cf
Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-120.00 hrs, dt= 0.0005 hrs
Starting Elev= 31.849' Surf.Area= 23,667 sf Storage= 40,167 cf
Peak Elev= 31.849' @ 0.00 hrs Surf.Area= 23,667 sf Storage= 40,167 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert Avail.Storage Storage Description
#1 30.000' 141,713 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
30.000 19,660 0 0
31.000 21,795 20,728 20,728
32.000 24,000 22,898 43,625
33.000 26,260 25,130 68,755
34.000 28,575 27,418 96,173
35.000 30,950 29,763 125,935
35.500 32,160 15,778 141,713
Device Routing Invert Outlet Devices
#1 Primary 30.000' 4.0" Vert. Low Flow Orifice C= 0.600
#2 Secondary 30.500' 15.0" Round Culvert
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 30.500' / 30.050' S= 0.0075 'P Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#3 Device 2 31.850' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 33.750' Emergency Spillway, C= 2.60
Offset (feet) 0.000 4.500 64.500 69.000
Height (feet) 1.50 0.00 0.00 1.50
Primary OutFlow Max=0.55 cfs @ 0.00 hrs HW=31.849' (Free Discharge)
L1=Low Flow Orifice (Orifice Controls 0.55 cfs @ 6.25 fps)
econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=31.849' (Free Discharge)
Culvert (Passes 0.00 cfs of 4.87 cfs potential flow)
3=Top of Box ( Controls 0.00 cfs)
=Emergency Spillway ( Controls 0.00 cfs)

15348.PE WQV Pond Drawdown Type Ill 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD010.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 3
Pond 15P: Wet Pond #3
Hydrograph
Inflow
Inpow-0,00 cfs,@0.00 hrs DUtfIOW
0.6 . f _ _ _ �utfow=0s$5 cfs 0300 hrs Prima
Prlmary=0.55 de:@ 0.06 hrs Primary
- _ - 0- rye° fs, ❑ Secondary
• $econ a ,00 c O.Ob hrs
0.55 Peak Pew31r849'
Storage=40,457 cf
... 0.4 -- ,- r--._r_..._7_-- - r---
0.3 ` r---r---r-----�.-.. �__
C
U.
0.2..----r---,-- ,--- , -- --
0.1 -
0 10 20 30 40 50 60 70 80 90 100110120
Time (hours)

15348.PE WQV Pond Drawdown Type /// 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Paae 4
Hydrograph for Pond 15P: Wet Pond #3
Time
Inflow
Storage
Elevation
Outflow
Primary
Secondary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
(cfs)
(cfs)
0.00
0.00
40,167
31.849
0.55
0.55
0.00
2.50
0.00
35,419
31.642
0.51
0.51
0.00
5.00
0.00
30,982
31.448
0.48
0.48
0.00
7.50
0.00
26,858
31.268
0.44
0.44
0.00
10.00
0.00
23,046
31.101
0.41
0.41
0.00
12.50
0.00
19,548
30.943
0.37
0.37
0.00
15.00
0.00
16,388
30.791
0.33
0.33
0.00
17.50
0.00
13,573
30.655
0.29
0.29
0.00
20.00
0.00
11,104
30.536
0.26
0.26
0.00
22.50
0.00
8,979
30.433
0.22
0.22
0.00
25.00
0.00
7,199
30.347
0.18
0.18
0.00
27.50
0.00
5,760
30.278
0.14
0.14
0.00
30.00
0.00
4,681
30.226
0.10
0.10
0.00
32.50
0.00
3,894
30.188
0.07
0.07
0.00
35.00
0.00
3,310
30.160
0.06
0.06
0.00
37.50
0.00
2,865
30.138
0.04
0.04
0.00
40.00
0.00
2,519
30.122
0.03
0.03
0.00
42.50
0.00
2,243
30.108
0.03
0.03
0.00
45.00
0.00
2,019
30.097
0.02
0.02
0.00
47.50
0.00
1,834
30.088
0.02
0.02
0.00
50.00
0.00
1,678
30.081
0.02
0.02
0.00
52.50
0.00
1,546
30.075
0.01
0.01
0.00
55.00
0.00
1,433
30.069
0.01
0.01
0.00
57.50
0.00
1,334
30.064
0.01
0.01
0.00
60.00
0.00
1,248
30.060
0.01
0.01
0.00
62.50
0.00
1,172
30.057
0.01
0.01
0.00
65.00
0.00
1,105
30.053
0.01
0.01
0.00
67.50
0.00
1,044
30.050
0.01
0.01
0.00
70.00
0.00
990
30.048
0.01
0.01
0.00
72.50
0.00
941
30.045
0.01
0.01
0.00
75.00
0.00
897
30.043
1 0.00 0.00 1
0.00
77.50
0.00
856
30.041
0.00
0.00
0.00
80.00
0.00
819
30.040
0.00
0.00
0.00
82.50
0.00
785
30.038
0.00
0.00
0.00
85.00
0.00
754
30.036
0.00
0.00
0.00
87.50
0.00
725
30.035
0.00
0.00
0.00
90.00
0.00
698
30.034
0.00
0.00
0.00
92.50
0.00
673
30.032
0.00
0.00
0.00
95.00
0.00
650
30.031
0.00
0.00
0.00
97.50
0.00
628
30.030
0.00
0.00
0.00
100.00
0.00
607
30.029
0.00
0.00
0.00
102.50
0.00
588
30.028
0.00
0.00
0.00
105.00
0.00
570
30.028
0.00
0.00
0.00
107.50
0.00
553
30.027
0.00
0.00
0.00
110.00
0.00
538
30.026
0.00
0.00
0.00
112.50
0.00
522
30.025
0.00
0.00
0.00
115.00
0.00
508
30.025
0.00
0.00
0.00
117.50
0.00
495
30.024
0.00
0.00
0.00
120.00
0.00
482
30.023
0.00
0.00
0.00
*Drawdown time calculated to 0.00 cfs outflow for 2-5 day requirement. This is a more
conservative approach as the last 1/2 inch of storage has a very long dewatering time.

15348.PE WQV Pond Drawdown Type Ill 24-hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD810.00-11 s/n 08877 ©2014 HydroCAD Software Solutions LLC Page 5
Summary for Pond 16P: Wet Pond #4
Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0 cl'
Outflow = 0.84 cis @ 0.00 hrs, Volume= 30,805 cf, Atten= 0%, Lag= 0.0 min
Primary = 0.84 cis @ 0.00 hrs, Volume= 30,805 cf
Secondary = 0.00 cis @ 0.00 hrs, Volume= 0 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-120.00 hrs, dt= 0.0005 hrs
Starting Elev= 35.041' Surf.Area= 32,070 sf Storage= 31,504 cf
Peak Elev= 35.041' @ 0.00 hrs Surf.Area= 32,070 sf Storage= 31,504 cf
Plug -Flow detention time= (not calculated: initial storage exceeds outflow)
Center -of -Mass det. time= (not calculated: no inflow)
Volume Invert Avail.Storage Storage Description
#1 34.000' 111,239 cf Custom Stage Data (Prismatic)Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
34.000 28,320 0 0
35.000 31,920 30,120 30,120
36.000 35,575 33,748 63,868
37.000 39,290 37,433 101,300
37.250 40,225 9,939 111,239
Device Routing Invert Outlet Devices
#1 Primary 34.000' 6.0" Vert. Low Flow Orifice C= 0.600
#2 Secondary 34.300' 23.0" W x 14.0" H, R=22.0" Elliptical RCP Elliptical 23x14
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 34.300' / 34.000' S= 0.0050 'P Cc= 0.900
n= 0.013, Flow Area= 1.83 sf
#3 Device 2 35.050' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 35.950' Emergency Spillway, C= 2.60
Offset (feet) 0.000 3.900 103.900 107.800
Height (feet) 1.30 0.00 0.00 1.30
Primary OutFlow Max=0.84 cfs @ 0.00 hrs HW=35.041' (Free Discharge)
L1=Low Flow Orifice (Orifice Controls 0.84 cfs @ 4.28 fps)
Eecondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=35.041' (Free Discharge)
2=RCP_Elliptical 23x14 (Passes 0.00 cfs of 2.93 cfs potential flow)
L3=Top of Box ( Controls 0.00 cfs)
=Emergency Spillway ( Controls 0.00 cfs)

15348.PE WQV Pond Drawdown Type 11124 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 6
oil
0.
-- 0.
0 0.
Pond 16P: Wet Pond #4
Hydrograph
0 10 20 30 40 50 60 70 80 90 100110120
Time (hours)
❑ Inflow
Outflow
❑ Primary
-! Secondary

15348.PE WOV Pond Drawdown Type M 24 hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD®10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC Page 7
Hydrograph for Pond 16P: Wet Pond #4
Time
Inflow
Storage
Elevation
Outflow
Primary
Secondary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
(cfs)
(afs)
0.00
0.00
31,504
35.041
0.84
0.84
0.00
2.50
0.00
24,515
34.814
0.71
0.71
0.00
5.00
0.00
18,726
34.622
0.58
0.58
0.00
7.50
0.00
14,134
34.469
0.45
0.45
0.00
10.00
0.00
10,766
34.357
0.31
0.31
0.00
12.50
0.00
8,495
34.282
0.21
0.21
0.00
15.00
0.00
6,939
34.230
0.14
0.14
0.00
17.50
0.00
5,829
34.194
0.11
0.11
0.00
20.00
0.00
5,007
34.166
0.08
0.08
0.00
22.50
0.00
4,378
34.145
0.06
0.06
0.00
25.00
0.00
3,883
34.129
0.05
0.05
0.00
27.50
0.00
3,485
34.116
0.04
0.04
0.00
30.00
0.00
3,159
34.105
0.03
0.03
0.00
32.50
0.00
2,887
34.096
0.03
0.03
0.00
35.00
0.00
2,656
34.088
0.02
0.02
0.00
37.50
0.00
2,459
34.082
0.02
0.02
0.00
40.00
0.00
2,289
34.076
0.02
0.02
0.00
42.50
0.00
2,140
34.071
0.02
0.02
0.00
45.00
0.00
2,009
34.067
0.01
0.01
0.00
47.50
0.00
1,893
34.063
0.01
0.01
0.00
50.00
0.00
1,789
34.059
0.01
0.01
0.00
52.50
0.00
1,696
34.056
0.01
0.01
0.00
55.00
0.00
1,612
34.054
0.01
0.01
0.00
57.50
0.00
1,535
34.051
0.01
0.01
0.00
60.00
0.00
1,466
34.049
0.01
0.01
0.00
62.50
0.00
1,402
34.047
0.01
0.01
0.00
65.00
0.00
1,344
34.045
0.01
0.01
0.00
67.50
0.00
1,290
34.043
0.01
0.01
0.00
70.00
0.00
1,240
34.041
0.01
0.01
0.00
72.50
0.00
1,194
34.040
1 0.00
0.00
1 0.00
75.00
0.00
1,152
34.038
0.00
0.00
0.00
77.50
0.00
1,112
34.037
0.00
0.00
0.00
80.00
0.00
1,075
34.036
0.00
0.00
0.00
82.50
0.00
1,040
34.035
0.00
-0.00
0.00
85.00
0.00
1,007
34.033
0.00
0.00
0.00
87.50
0.00
976
34.032
0.00
0.00
0.00
90.00
0.00
948
34.031
0.00
0.00
0.00
92.50
0.00
920
34.031
0.00
0.00
0.00
95.00
0.00
895
34.030
0.00
0.00
0.00
97.50
0.00
870
34.029
0.00
0.00
0.00
100.00
0.00
847
34.028
0.00
0.00
0.00
102.50
0.00
825
34.027
0.00
0.00
0.00
105.00
0.00
804
34.027
0.00
0.00
0.00
107.50
0.00
785
34.026
0.00
0.00
0.00
110.00
0.00
766
34.025
0.00
0.00
0.00
112.50
0.00
748
34.025
0.00
0.00
0.00
i i 5.00
0.00
731
34.024
0.00
0.00
0.00
117.50
0.00
714
34.024
0.00
0.00
0.00
120.00
0.00
699
34.023
0.00
0.00
0.00
*Drawdown time calculated to 0.00 cfs outflow for 2-5 day requirement. This is a more
conservative approach as the last 1/2 inch of storage has a very long dewatering time.

STORMWATER CALCULATIONS
INFILTRATION BASINS

Project Name:
Surf City K-8
Client:
LS313
Project Number:
15348.PE
Prepared By:
DJF
Date:
4/25/16
Secondary Infiltration System Design #1
Impervious Area:
Total Impervious Area
Soils Testing Information:
Soil Type =
EL. At Test Location =
Depth to SHWL =
SHWL =
Infiltration Rate =
1/2 Infiltration Rate =
247,100 sf
Leon fine sand (LnA)
36.00
2.0 ft
34_n
3.13 in/hr
1.565 in/hr
Stormwater Quality Requirement:
Drainage Area to System =
10.82 Ac.
Impervious Area =
5.67 Ac.
Impervious
52.45 %
Runoff CoefFlcent (Rv) =
0.522 in/in
Req. 1.5" Runoff Volume =
N/A cf
lyr Volume (Simple Method)
64,864 cf
2X lyr Volume
129,728 cf
Weir Elevation =
36.00 EL.
[craw Down Analysis:
I ..... ----- -AA--------------- --- _ .i_.............. T-._..- .......
PAR
Bottom Area of Basin 9,815 sf
Bottom Elevation of Basin 35.00 EL.
Basin Depth 1.00 ft
Draw Down Time = 4.22 days (from Darcy{s Equation)

Project Name:
Surf City K-8
Client:
LS3P
Project Number:
15348.PE
Prepared By:
DJF
Date:
4/25/16
Secondary Infiltration System Design *2
Impervious Area:
Total Impervious Area
Soils Testing Information:
Soil Type =
EL. At Test Location =
Depth to SHWL =
SHWL =
Infiltration Rate =
1/2 Infiltration Rate =
99,125 sf
Leon fine sand (LnA)
33.00
1.0 ft
32.0
2.15 in/hr
1.075 in/hr
Stormwater Quality Requirement:
Drainage Area to System
4.83 Ac.
Impervious Area =
2.28 Ac.
% Impervious
47.12 %
Runoff Coefficent (Rv) =
0.474 in/in
Req. 1.5" Runoff Volume =
N/A cf
iyr Volume (Simple Method)
26,020 cf
2X iyr Volume
52,040 cf
Weir Elevation =
34.00 EL.
Draw Down Analysis:
...................... _._.... __.................. .................. ..... ........ ....................... .._.... ................
.U.-VR..AMOUNTE
Bottom Area of Basin 5,725 sf
Bottom Elevation of Basin 33.00 EL.
Basin Depth 1.00 ft
Draw Down Time = 4.23 days (from Darcy's Equation)

Project Name:
Surf City K-8
Client:
LS3P
Project Number:
15348.PE
Prepared By:
DJF
Date:
4/25116
PARAMOUNTE
t N . f N Y t f$ 1 N s , N C
Secondary Infiltration System Design #3
Impervious Area:
Total Impervious Area
Solis Testing Information:
Soil Type =
EL. At Test Location =
Depth to SHWL =
SHWL =
Infiltration Rate =
1/2 Infiltration Rate =
273,000 sf
Mandarin fine sand (Ma)
36.00
2.08 ft
33.92
1.48 In/hr
0.74 in/hr
Stormwater Quality Requirement:
Drainage Area to System =
14.42 Ac.
Impervious Area =
6.27 Ac.
% Impervious
43.46 %
Runoff Coefficent (Rv) =
0.441 in/in
Req. 1.5" Runoff Volume =
N/A cf
1yr Vol. From 3 (Simple Method)
40,163 cf
1yr Vol. From 4 (Simple Method)
34,369 cf
lyr Volume (Total)
74,532 cf
Weir Elevation =
36.00 EL.
Draw Down Analysis:
Bottom Area of Basin 5,800 sf
Bottom Elevation of Basin 35.00 EL.
Basin Depth 1.00 ft
Draw Down Time 4.00 days (from Darcy's Equation)

STORMWATER CALCULATIONS
STORMWATER PUMPS

`X4�y' I T T
Water & Wastewater
Flygt 2610 de-%watenrig pump
Designed without compromise
The Flygt 2600 series from ITT Water &
Wastewater represents a major breakthrough
in dewatering pump technology. Radically
engineered from the ground up, these robust
pumps deliver unmatched wear resistance,
consistent performance over time, and ease
of service. The result is lower overall cost of
ownership.
The smallest pump in the range, the Flygt 2610
delivers impressive performance for smaller -scale
applications. Its open impeller design minimizes
clogging, giving sustained performance over time. It's
easy to adjust the impeller for optimum performance,
with just one adjustment screw.
Cutting -edge design with fewer components
makes this pump simple and quick to maintain. A
removable top gives effortless access to the junction
box, and external oil and inspection plugs facilitate
maintenance. The inspection chamber improves
protection and extends service intervals. The
unique one-piece Plug -In' seal provides superior
protection and is easy to replace.
r
This advanced technology is backed by ITT Water &
f �If
$
a nding support and worldwide
�
presence. Operating n over 140 countries, we bring
many years of experience to bear in order to keep
your business moving.
Engineered for life 60Hz

2610.171
60Hz
Aluminium discharge
connection
Single adjustment
screw
- Easy to adjust for
optimum performance
Inspection chamber
- Improved protection
Specially designed . p
Hard -Iron'" clog- -
resistant impeller
- High efficiency
sustained over time Al
'��' Convenient handle
a
^(
Removable top
- Easy to access
i1
electrical components
Built-in capacitors
- Easy to handle
Plug -In"' seal
- Easy to service,
} f
j
double protection
Corrosion and impact
\
resistant strainer
Rubbershock
absorbers
- Impact resistant
I-'-�
2610.171
Submersible pump for dewatering of con-
struction sites, mines, draining of flooded
areas and other similar applications where
the liquid may contain abrasive particles.
Denomination
Product code 2610.171
Installation Portable
Impeller characteristics
Medium head (MT)
Clog resistant (K)
Discharge connection 2"
Process data
Liquid temperature max +104°F/ +40°C
Depth of immersion max 65.62 ft / 20 m
Liquid density max 1100 kg/m3
Strainer hole size 0.24" x 0.53" /
6mmx13.5mm
The pH of the pumped liquid pH 5-8
Motor data
Squirrel cage 1-phase and 3-phase
induction motor
Frequency 60Hz
Insulation class F (+311 °F / +155°C)
Voltage variation
- continuous running max ± 5%
- intermittent running max ± 10%
Voltage imbalance
between phases
No. of starts/hour
Spin -Out"
- Minimizes clogging
and seal wear
/External
oil and
inspection plugs
- Easy to inspect
and service
Cables
SUBCABO Submersible cable
SUBCAB® Screened Heavy duty rubber
submersible cable
Monitoring equipment
Thermal contacts
opening temperature +257°F / +125°C
Materials
Outer casing
Aluminum alloy
Impeller
Hard -Iron'"
white cast iron
Wear parts
Nitrile rubber
Stator housing
Aluminum alloy
Strainer
Stainless steel
Shaft
Stainless steel
O-rings
Nitrile rubber
Discharge connection
Aluminum
Mechanical face seals
Inner Tungsten carbide/Ceramic
Outer Tungsten carbide
Weight
Total (excl. cable)
1-- 1.3 hp 42 Ibs/ 19 kg
1-- 1.8 hp 49 Ibs / 22 kg
3--- 1.9 hp 42 Ibs/ 19 kg
Dimensions
max 2% Height 23.4" / 594 mm
max 30 Diameter 7.7" / 195 mm
www.ittwww.com
Performance
H [ft] / [m]
60 18
16
50
14
40 12
10
30
8
20 6
4
10
2
0 0
0 2 4 6 8 10
I
0 20 40 60 80 100 120 140 160 180
Q [I/s] /[usgpm]
K=Clog resistant impeller
Options
Warm liquid version max 158°F / +700C
Quick couplings 2"
Starters
Zinc anodes
Low suction collar
Accessories
Adapters, hose connections and other
mechanical accessories. Electrical
accessories such as pump controller,
control panels and monitoring relays.
Rating
1-,3-
Rated output 1- 1.3 hp / 1.0 kW
1- 1.8hp/1.3kW
3- 1.9 hp / 1.4 kW
Speed of rotation 1--- 1,3 hp 3410 rpm
1- 1.8 hp 3475 rpm
3- 1,9 hp 3335 rpm
Voltage
V
Rated
current
A
Starting
current
A
1-1,3
115
12
49
1--1.3
220
6.0
23
1-1,3
230
5.8
24
1-1.3
240
5.7
26
1-1.8
115
15
74
1-1.8
220
7.5
35
1-1.8
230
7.4
37
1---1.8
240
7.5
39
3-1.9
220 D
5.4
29
3- 1.9
230 Y
5.2
27
3--- 1.9
380 Y
3.1
17
3- 1.9
460 Y
2.6
14
3- 1.9
480 Y
2.6
14
3- 1.9
575 Y
2.0
10
3--- 1.9
600
2.0
10

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15348. PE SWM POST Type 111 24-hr 1-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HydroCAD®10.00-11 s/n 08877 02014 HydroCAD Software Solutions LLC
Summary for Pond 16P: Pump #3
Inflow = 0.21 cfs @ 11.96 hrs, Volume= 6,423 cf
Outflow = 0.14 cfs @ 14.80 hrs, Volume= 6,346 cf, Atten= 33%, La = 170.6 min
Primary = 0.14 cfs @ 14.80 hrs, Volume= 16,346 cf IPUMPED VOLUME DURING 24 HOUR STORM:
Secondary = 0.00 cfs @ 0,00 hrs, Volume= 0 d 6,346 d 140,163 Cf = 15.8%
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-24.00 hrs, dt= 0.0005 hrs
Starting Elev= 29.00' Suri.Area= 28 sf Storage= 70 cf --
Peak Elev= 31.81' @ 15.44 hrs Surf.Area= 28 sf Storage= 149 cf (79 cf above start)
Plug -Flow detention time= 17.2 min calculated for 6,276 cf (98% of inflow)
Center -of -Mass det. time= 4.2 min ( 1,065.4 - 1,061.2 )
Volume Invert Avail.Storage Storage Description
#1 26.50' 252 cf Wet Well (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
26.50 28 0 0
27.00 28 14 14
29.00 28 56 70
30.00 28 28 98
31.00 28 28 126
32.00 28 28 154
33.00 28 28 182
35.50 28 70 252
Device Routing Invert Outlet Devices
#1 Primary 30.00' Flygt 2610 K 235 MT
Discharges@35.00' Turns Off@29.00'
3.0" Diam. x 1,750.0' Long Discharge, Hazen -Williams C= 140
Flow (gpm)= 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0
Head (feet)= 43.00 36.00 31.00 25.00 19.00 15.00 10.00 4.00
-Loss (feet)= 0.00 2.36 8.53 18.08 30.80 46.56 65.26 86.81
=Lift (feet)= 43.00 33.64 22.47 6.92 -11.80 -31.56 -55.26
-82.81
#2 Secondary 30.00' 4.0" Vert. Low Flow Orifice C= 0.600
rimary OutFlow Max=0.14 cfs @ 14.80 hrs HW=31.79' TW=35.23' (Dynamic Tailwater)
1=Flygt 2610 K 235 MT (Pump Controls 0.14 cis)
§econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=29.00' TW=30.00' (Dynamic Tailwater)
' -2=Low Flow Orifice ( Controls 0.00 cfs)

15348.PE SWM POST Type 111 24-hr 9-Year Rainfall=3.50"
Prepared by Paramounte Engineering, Inc. Printed 4/25/2016
HvdroCAD® 10.00-11 s/n 08877 © 2014 HydroCAD Software Solutions LLC
Summary for Pond 18P: Pump #4
Inflow =
0.14 cfs @
11.68 hrs,
Volume=
4,649 cf
Outflow =
0.10 cfs @
14.04 hrs,
Volume=
4,592 cf Atten= 30%, La = 141.4 min
Primary =
0.10 cfs @
14.04 hrs,
Volume=
4,592 cf PUMPED VOLUME DURING 24 HOUR STORM:
Secondary =
0.00 cfs @
0.00 hrs,
Volume=
0 cf 1 4,592 cf / 31,500 cf = 14.6%
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-24.00 hrs, dt= 0.0005 hrs
Starting Elev= 33.00' Surf.Area= 28 sf Storage= 70 cf
Peak Elev= 35.07' @ 16.57 hrs Surf.Area= 28 sf Storage= 128 cf (58 cf above start)
Plug -Flow detention time= 22.5 min calculated for 4,522 cf (97% of inflow)
Center -of -Mass det. time= 4.6 min ( 1,039.3-1,034.7 )
Volume Invert
Avail.Storage Storage Description
#1 30.50'
189 cf Wet Well (Prismatic) Listed below
Elevation Surf.Area
Inc.Store Cum.Store
(feet)
(sq-ft)
(cubic -feet) (cubic -feet)
30.50
28
0 0
31.00
28
14 14
32.00
28
28 42
33.00
28
28 70
34.00
28
28 98
35.00
28
28 126
36.00
28
28 154
37.25
28
35 189
Device Routing
Invert
Outlet Devices
#1 Primary
34.00'
Flygt 2610 K 239 MT
Discharges@35.00' Turns Off@33.00'
2.0" Diam. x 1,010.0' Long Discharge, Hazen -Williams C= 140
Flow (gpm)= 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0
Head (feet)= 55.00 50.00 43.00 35.00 30.00 25.00 18.00 12.00
4.00
-Loss (feet)= 0.00 9.83 35.48 75.17 128.07 193.60 271.35
361.00 462.27
=Lift (feet)= 55.00 40.17 7.52 -40.17 -98.07-168.60-253.35
-349.00-458.27
#2 Secondary
30.00'
6.0" Vert. Low Flow Orifice C= 0.600
rimary OutFlow Max=0.10 cfs @ 14.04 hrs HW=34.99' TW=35.18' (Dynamic Tailwater)
1=Flygt 2610 K 239 MT (Pump Controls 0.10 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=33.00' TW=34.00' (Dynamic Tailwater)
2=Low Flow Orifice ( Controls 0.00 cfs)

STORMWATER CALCULATIONS
LEVEL SPREADERS

15348.PE SWIM POST Type /// 24-hr 10;Yea, Rainfall=6.50"
Prepared by Paramounte Engineering, Inc. Printed 4/26/2016
HydroCAD®10.00-11 s/n 08877 ® 2014 HydroCAD Software Solutions LLC
Summary for Pond 15P: Wet Pond #3
Inflow = 50.73 cfs @ 12.07 hrs, Volume= 152,265 cf
Outflow = 8.41 cfs @ 12.54 hrs, Volume= 135,410 cf, Atten= 83%, Lag= 27.9 min
Primary = 0.19 cfs @ 12.08 hrs, Volume= 31,443 cf
Secondary 1 8.26 cfs 12.54 hrs, Volume= 103,966 cf
04 QZML WIL Fuw 'iD UGWN1.. Sl(l! *AD"
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 33.20' @ 12.54 hrs Surf.Area= 26,713 sf Storage= 74,122 cf
Plug -Flow detention time=489.8 min calculated for 135,410 cf (89% of inflow)
Center -of -Mass det. time=437.5 min (1,247.5 - 810.0 )
Volume Invert Avail.Storage Storage Description
#1 30.00' 141,713 cf Custom Stage Data (Prlsmatic�isted below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
30.00 19,660 0 0
3100 21,795 20,728 20,728
32.00 24,000 22,898 43,625
33.00 26,260 25,130 68,755
34.00 28,575 27,418 96,173
35.00 30,950 29,763 125,935
35.50 32,160 15,778 141,713
Device Routing Invert Outlet Devices
#1 Primary 30.00' 4.0" Vert. Low Flow Orifice C= 0.600
#2 Secondary 30.50' 15.0" Round Culvert
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 30.50' / 30.05' S= 0.00751' Cc= 0.900
n= 0.012, Flow Area=1.23 sf
#3 Device 2 31.85' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 33.75' Emergency Spillway, C= 2.60
Offset (feet) 0.00 4.50 64.50 69.00
Height (feet) 1.50 0.00 0.00 1.50
Primary OutFlow Max=0.19 cfs @ 12.08 hrs HW=32.30' TW=32.09' (Dynamic Tailwater)
't-1=Low Flow Orlflce (Orifice Controls 0.19 cfs @ 2.18 fps)
le:condary OutFlow Max=8.26 cis @ 12.54 hrs HW=33.20' TW=0.00' (Dynamic Tailwater)
Culvert (Barrel Controls 8.26 cfs @ 6.73 fps)
3=Top of Box (Passes 8.26 cfs of 50.27 cfs potential flow)
Emergency Spillway ( Controls 0.00 cfs)

15348.PE SWM POST Type 111 24-hr 10-Year Rainfall=6.50"
Prepared by Paramounte Engineering, Inc. Printed 4/26/2016
HydroCAD®10.00-11 s/n 08877 02014 HydroCAD Software Solutions LLC
Summary for Pond 17P: Wet Pond #4
Inflow = 28.14 cfs @ 12.07 hrs, Volume= 89,259 cf
Outflow = 6.23 cfs @ 12.46 hrs, Volume= 73,241 cf, Atten= 78%, Lag= 23.5 min
Primary = 0.12 cfs 9.55 hrs, Volume= 21,867 cf
Secondary= 6.1 cfs 12.46 hrs, Volume= 51,374 cf
Routing by Sim -Route method w/Net Flows, Time Span= 0.00-72.00 hrs, dt= 0.0005 hrs
Peak Elev= 35.50' @ 12.46 hrs Surf.Area= 33,755 sf Storage= 47,062 cf
Plug -Flow detention time=626.1 min calculated for 73,240 cf (82% of inflow)
Center -of -Mass det. time=555.2 min ( 1,332.8 - 777.7 )
Volume Invert Avail.Storage Storage Description
#1 34.00' 111,239 cf Custom Stage Data (Prismatic) -fisted below
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
34.00 28,320 0 0
35.00 31,920 30,120 30,120
36.00 35,575 33,748 63,868
37.00 39,290 37,433 101,300
37.25 40,225 9,939 111,239
Device Routing Invert Outlet Devices
#1 Primary 34.00' 6.0" Vert. Low Flow Orifice C= 0.600
#2 Secondary 34.30' 23.0" W x 14.0" H, R=22.0" Elliptical RCP -Elliptical 23x14
L= 60.0' Box, headwall w/3 square edges, Ke= 0.500
Inlet / Outlet Invert= 34.30' / 34.00' S= 0.0050'/' Cc= 0.900
n= 0.013, Flow Area=1.83 sf
#3 Device 2 35.05' 36.0" x 36.0" Horiz. Top of Box C= 0.600
Limited to weir flow at low heads
#4 Secondary 35.95' Emergency Spillway, C= 2.60
Offset (feet) 0.00 3.90 103.90 107.80
Height (feet) 1.30 0.00 0.00 1.30
Primary OutFlow Max=0.12 cfs @ 9.55 hrs HW=34.21' TW=34.10' (Dynamic Tailwater)
t--1=Low Flow Orifice (Orifice Controls 0.12 cfs @ 1.55 fps)
econdary OutFlow Max=6.14 cfs @ 12.46 hrs HW=35.50' TW=0.00' (Dynamic Tailwater)
2=RCP_Elliptical 23xl4(Barrel Controls 6.14 cfs @ 4.09 fps)
t-3=Top of Box (Passes 6.14 cfs of 11.93 cfs potential flow)
4=Emergency Spillway( Controls 0.00 cfs)

For DENR Use ONLY
Reviewer. _ L
' North Carolina Department of Environment and
Submit:
� Natural Resources y
NCDENR Request for Express Permit Review Time:
Confirm:
FILL-IN all the information below and CHECK the Pernit(s) you are requesting for express review. CaN and Email the completed form to the
Permit Coordinator along with a completed DETAILED narrative site plan (PDF rile) and vicinity map (same items expected in the application
acka a of the project location. Please include this form in the application package.
• Asheville Region Alison Davidson 828-296-4698;a/ison.davidson(rkncdenrsrov
• Fayetteville or Raleigh Region -David Lee 919-7914203, daviddeeAncdennoov
• Mooresville & Winston Salem Region - Patrick Grogan 704-235-2107 or patrick.progan(c&ncdenruov
• Washington Region Lyn Hardison 252-9484842 or lyn.hardisomemcdenngov
• Wilmington Region -Janet Russell 910-796-7302 orlanetrusseA(abncdenr.gov
• Wilmington Region -Cameron Weaver 910-796-7303 or cameron.weaverOncdenr.goov
NOTE: Project application received after 12 noon will be stamped in the following work day.
Project Name: SURF CITY K-8 SCHOOL County: PENDER
Applicant: KENNETH FULLER Company: PENDER COUNTY SCHOOLS
Address: 925 PENDERLEA HWY. City: BURGAW, State: NC Zip: 28425-_
Phone: [phone], Fax: [phone], Email: kenneth [e-mail]
related to this Protect
SW
SW
SW
NPDES _
NPDES
wo
VY Q
E&S
E&S
Other
Physical Location:SHEPARDS DRIVE
Project Drains into BECKY'S CRK, COUNTY LINE BRNCH waters — Water classification SA, HQW (for classification see-
httn:llportal.ncdenr.org/web/wg/ps/csu/classifications)
Project Located in CAPE FEAR River Basin. Is project draining to class ORW waters? N within %mile and draining to class SA waters Y or within 1 mile
and draining to class HQW waters? Y
Engineer/Consultant: ROB BALLAND. PE Company: PARAMOUNTE ENGINEERING, INC
Address: 5911 OLEANDER DRIVE, STE 201 City: WILMINGTON. State: NC Zip: 28403-_
Phone: [phone]. Fax: [phone], Email: [e-mail]
PLEASE PROVIDE ESTIMATED INVESTMENT AND EXPECTED EMPLOYMENT, IF AVAILABLE
$ # JOBS
SECTION ONE: REQUESTING A SCOPING MEETING ONLY
❑ Scoping Meeting ONLY ❑ DWQ, ❑ DCMAJ❑ DLR, ❑ OTHER:
SECTION TWO: CHECK ONLY THE PROGRAM (*YOU ARE REOUES
❑ 401 Unit ❑ Stream Origin Determination: _ # of stream calls — Please attach TOPO map marking the areas in questions
EllntiErmittent/Perennial Determination: _ # of stream calls - Please attach TOPO map marking the areas in questions
❑.401 Water Quality Certification ❑ Isolated Wetland (_linear ft or _acres)
❑ Riparian Buffer Authorization ❑ Minor Variance ❑ Major General Variance
® State Stormwater ❑ General ❑ SFR, ❑ SFR < 1 ac. ❑ �Bkhd & Bt Rmp, ❑ Clear & Grub, ❑ Utility ❑ Other
❑ Low Density ❑ Low Density -Curb & Gutter _ # Curb Outlet Swales ❑ Off -site [SW (Provide permit #)]
® High Density -Detention Pond 4 # Treatment Systems ® High Density4nfiltration 3 #Treatment Systems
❑ High Density -Bio-Retention _ # Treatment Systems ElHigh Density —SW Wetlands _ # Treatment Systems
ElHigh Density -Other _# Treatment Systems /❑ P. [l Min. r ❑ Plan REtiis'atl [ R~dev, E;:c'.: ;n 5A, (Rovkp.,resmi_;-1
❑ Coastal Management ❑ Excavation & Fill ❑ Bridges & Culverts ❑ Structures Information
❑ Upland Development ❑ Marina Development ❑ Urban Waterfront
® Land Quality ® Erosion and Sedimentation Control Plan with _ acres to be disturbed.(CK # (for DENR use))
SECTION THREE —PLEASE CHECK ALL THAT IS APPLICABLE TO YOUR PROJECT (for both scoping and express meeting request)
Wetlands on Site ® Yes ❑ No
Wetlands Delineation has been completed: Z Yes ❑ No
US ACOE Approval of Delineation completed: ® Yes ❑ No
Received from US ACOE ❑ Yes ® No
-- _-- For DENR use only
Fee Split for multiple permits: (Check # 1
Buffer Impacts: ® No ❑ YES: _acre(s)
isolated wetiand on Property ❑ Yes Z No
404 Application in Process w/ US ACOE: ® Yes ❑ No Permit
Fee Amount
SUBMITTAL DATES
Fee
SUBMITTAL DATES
Fee
CAMA
$
variance (❑ Maj; ❑ Min)
$
SW (❑ HD, ❑ LD, ❑ Gen)
$
401:
$
LQS
$
Stream Deter,_
$
NCDENR EXPRESS October 2013

Surf City K-8 School
Express Stormwater Narrative
March 2016
Project Narrative:
Pender County Schools is proposing to construct a new K-8 School with associated parking,
sidewalks, and recreational facilities on an 84.92 acre parcel of land located in the southeast
portion of Pender County near Surf City. The parcel is further identified by Pender County
Parcel Identification Number#: 4226-92-2047-0000.
We are anticipating that this will be a high density project. The project is within two drainage
basins, Becky's Creek and County Line Branch, each with a stream classification of SA, HQW.
We believe that the proposed outfalls that drain to both Becky's Creek and County Line Branch
are within 1/2 mile and draining to the creek.
The storm water runoff from this project will be conveyed within the limits listed above via a
combination of swales, overland flow, and underground piped conveyance to one of four (4)
proposed wet detention basins which will convey the treatment volume as a BMP in series to
one of three (3) infiltration basins proposed on the site.

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FIOLLY RHIGB, NC
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Hall; Christine
From: Hall, Christine
Sent: Wednesday, March 23, 2016 10:03 AM
To: Rob Balland; Gretchen Merix ([e-mail])
Cc: Weaver, Cameron
Subject: Surf city K-8
Rob / Gretchen,
Cameron approached me to schedule this project, but it looks like the provided documentation (narrative and maps) is
the same as the low density request from January. E-mails to Cameron in early March and the revised Express request
indicates this is now a high density project. Can you please confirm the documents you provided with the Express
request describe the current site design?
Thanks,
Christine
Christine (Nelson) Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources — State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
[e-mail]
127 Cardinal Drive Ext.
Wilmington, NC 28405
Etf,d;' �G "E`Sj1^d i t" Ge t,: and rorP? ttiis aL e: s �S S:f1'
Xcntn Caro inn 1='ob!i PeCo,'ds Latv And may be G°r : ;!C s Y to . Iird earl ens.

Dropbox - REQUEST FOR EXPRESS - SURF CITY K-8.pdf Page 1 of 1
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https://www.dropbox.com/sh/n2esokpbf9i9d3m/AAB55UTbEpRUktXOtmA 10-hGa/REQU... 3/23/2016

Dr'o'pbox - Express Stormwater Narrative - Surf City K-8.pdf Page I of 1
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Surf City K-8 School
Express Stormwater Narrative
januarv2016
Fr9ject Narrative:
P#--C.= Cmw-t7 Schools is popesing is constr.;ct a nLm- _K4 wssceate d pafidr.g.
kde-.,7alks, and recreat:a-,K facilities ar- ar- acre paroel Df .-3nd-'�'.-ocated :n -:!ite c3u---easst
Fartm. of Fender C-.Ln—. near Surf Qtr. The puree:. is --ffter --!ertif-ed 'b- Fender Count -
Parcel. Identificatc-n !Qumberl:
V%'e are an--:z--r,&tir.g tha- fnir wl -e a denu,t- pr.cecL The T-YeCL4 -S kin-t a drainage
bazxs. Beck -as Creek and Ccu&.7 L:ne Brandt, each. T­-th ajj e arJ Sk HQI%'-
.Z
I mL-
'Ve -_-e_ieve that the pzztm cf the prcp;er.t-, thai drains to Becka --K
Jrair.to the meek,, ffierefc:e- ,,-e are rezruef tin thatt- partio
(2,ject ay has �c
imper-ricus area draining to Becky's Creek. The z'-ier partion to Ca, arty Line
Brar.2- V.'e '-LLere the pzr--on a= t�7.e r;rc]'eA is pWgp�ta kAMA-&kIAEqOoK.--I
thezefore aze recpest g 2r4`� j=-per:rious. --he M
eazk- basin ar d the requested Icr; derra -sity impevas areas. ry-MeTm.
IP DA-11 k'Beckr's Creek: 33-3 acres '-2",, = 4.' acres! 174,066 s!-
a DA-2.i, Ccunt-,- LZne Branc:74 51.6 aaes 'A;*o = 11.1 acres (539,447 sP
The storm -.-ater rurmff fro= the prqject i-.,M be co-i-eyell fhe Urr,& listed aCcove
rv.-ales and oet!aL to surz-a-and-r-g-v. etlards -.-:1hich dxa-:r, tc ea&outfaLl.
https:llwww.dropbox.comlshln2esokpbf9i9d3mlAA-A�PTgO5bv9HjtG9lc9Ks89nalExpress... 3/23/2016

Dropbox - 15348.PE DRAINAGE AREA MAP.pdf
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Raw
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-t
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e�
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VI
,?cist$a �mrnent to sta a discussion.
o notify them.
https://www.dropbox.corn/sh/n2esokpbf9i9d3nVAAC7JwAf6Fl8YYOITglCgzLEa/15348.... 3/23/2016

Diopbox - Quad Map.pdf
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MUM J! Ivi..
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.3i
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Dfopbox - SURF CITY K-8 LOCATION MAP.pdf
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14 r
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-=�@Mention someone to notifytl
M
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n.
https://www.dropbox.com/sh/n2esokpbf9i9d3m/AACnKfzRCQlC8NMTH4d wrRa/SU... 3/23/2016

Weaver, Cameron
From: Folta, Christine W SAW <[e-mail]>
Sent: Monday, March 21, 2016 4:01 PM
Subject: US Army Corps of Engineers Public Notice
As you requested, you are hereby notified that the Wilmington District, United States Corps of Engineers, has issued a
Public Notice. The text of this document can be found on the Public Notices portion of the Regulatory Division Home
Page. Each Public Notice is available in ADOBE ACROBAT (.pdf) format for viewing, printing or download
at: http://www.saw.usace.army.mil/Missions/RegulatoryPermitProgram.aspx.
The current notice involves:
Corps Action ID#: SAW-2016-00507
Issue Date: March 21, 2016
Applicant: Pender County Schools
Expiration Date: April 19, 2016
Point of Contact: Ms. Emily (freer, Project Manager
Project Description:
The Wilmington District, Corps of Engineers (Corps) received an application from Pender County Schools seeking
Department of the Army authorization to impact Waters of the US, associated with the construction of a K-8 school with
associated recreational fields, access road, parking, and stormwater facilities in Surf City, Pender County, North Carolina.
Subscribe/Unsubscribe: This email was sent out as a result of subscribing to the Wilmington District regulatory program
public notices. Please email <mailto:[e-mail] <mailto:[e-mail]> >
with the subject or message "unsubscribe" to remove your address. from future mailings.

Weaver, Cameron
From:
Weaver, Cameron
Sent:
Thursday, March 17, 2016 3:25 PM
To:
Robert Balland
Subject:
RE: Surf City K-8
Unfortunately you need to resubmit the request with updates from when you postponed it. When I receive, I'll schedule
as quickly as possible and we'll go over the projects that your firm has in line here.
Cameron Weaver
Environmental Assistance Coordinator -Wilmington Regional Office
NCDEQ-Division of Environmental Assistance and Customer Service
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7303
NCDEQ NEW WEBSITE: http:/Ideo.nc.eov/
DEACS NEW WEBSITE: http://deo.nc.eov/about/divisions/environmental-assistance-customer-service
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.
From: Robert Balland [mailto:[e-mail]]
Sent: Thursday, March 17, 2016 2:49 PM
To: Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8
Cameron,
Did we ever get this on the schedule for express review or where you waiting on my for something?
Thanks,
•..
From: Weaver, Cameron [mailto:cameron.weaver@a ncdenrgov]
Sent: Thursday, March 03, 2016 2:43 PM
To: Robert Balland <rballand@pi ramounte-eng_com_>
Subject: RE: Surf City K-8
Ems
! know what I told you yesterday about Christine's date, and unfortunately I am going to have to push that out because
I've been slammed today from others in your firm and elsewhere with Express requests. Get this request back in asap to
get into the queue if you need to meet your deadlines. End of May dates will be handed out shortly with the current
pace of requests.
Cameron

Cameron Weaver
Environmental Assistance Coordinator -Wilmington Regional Office
NCDEQ-Division of Environmental Assistance and Customer Service
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7303
NCDEQ NEW WEBSITE: http://deg.nc.gov/
DEACS NEW WEBSITE: http://deq nc.gov/about/divisions/environmental-assistance-customer-service
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.
From: Weaver, Cameron
Sent: Wednesday, March 02, 2016 11:35 AM
To: Robert Balland <rballand aran10Unte-e_rg.com>
Subject: RE: Surf City K-8
Hi Rob.
Currently, Christine's next date (with a couple already in house to schedule yet) is April 14. So, yes, by the time you have
things prepared for scheduling, we will likely be at the end of April.
Cameron Weaver
Environmental Assistance Coordinator -Wilmington Regionai Office
NCDEQ-Division of Environmental Assistance and Customer Service
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7303
NCDEQ NEW WEBSITE: http://deg.nc.gov/
DEACS NEW WEBSITE: http•//deq nc.gov/about/divisions/environmental-assistance-customer-service
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.
From: Robert Balland [mailto:[e-mail]]
Sent: Wednesday, March 02, 201611:16 AM
To: Weaver, Cameron <[e-mail]>
Subject: RE: Surf City K-8
Cameron,
I just finished a staff meeting about this site and I was going to reach out to you early next week with an update, but
now that you emailed me, I will update you now. We will likely submit for an express request next week or early the
following week for storm water and erosion control. I would assume that would put our scheduled review time around
the end of April? One other question I have. It's been determined that this project is within % miles of SA waters, so we
are proposing to have wet detention basins in series with infiltration basins. One of the wet detention basins will have
to pump the water quality volume to an infiltration basin, are there any issues with that going through the express
program? I just wanted to ask so we do not hit any road blocks later. School projects are always on a tight schedule.
Thanks,

Rob
From: Weaver, Cameron Qmaiito:cameron.weaver ncdenr.ov
Sent: Wednesday, March 02, 201611:09 AM
To: Robert Balland <rbagandL&okramounte_eng.co_n>
Subject: RE: Surf City K-19
Hi Rob
Vve still got this on my radar. Should I just remove it for now so that I don't keep bugging you about status?
Cameron Weaver
Environmental Assistance Coordinator -Wilmington Regional Office
NCDEQ-Division of Environmental Assistance and Customer Service
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7303
NCDEQ NEW WEBSITE: http://deg.nc.eov/
DEACS NEW WEBSITE: http://deg.nc.gov/about/divisions/environmental-assistance-customer-service
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.
From: Robert Balland[mailtoµrballandjparamounte-engcoml
Sent: Thursday, January 14, 2016 4:57 PM
To: Weaver, Cameron <cameronweaver ncdenr.eov>
Subject: FW: Surf City K-8
See attached.
From: Gretchen Merix
Sent: Thursday, January 14, 2016 3:54 PM
To: Robert Balland <rbaIland_�1a paramounte-eng.com>
Subject: Surf City K-8
Cameron called and said he needs a quad with the % mile circle before he can schedule your meeting.
Gretchen Merix, E.I.
Paramounfe Engineering, Inc
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
v: 910.791.6707
f: 910.791.6760
w: htto://www.paramounte-en-g.com

Hall, Christine
From:
Hall, Christine
Sent:
Friday, January 15, 2016 9:42 AM
To:
Rob Balland
Cc:
Weaver, Cameron; Steenhuis, Joanne
Subject:
RE: Surf City K-8
Rob, .
I took a look at the map you provided, the USGS quad sheet, and the Surface Water Classifications Mapper from DWR
and it appears that County Line Branch extends beyond the point you indicated. I discussed this situation with Joanne,
and she indicated that County Line Branch does extend beyond HWY 17. As I'm sure you area aware, County Line
Branch is considered SA; HOW from the source to Batts Mill Creek. Please work with DWR to confirm the source of the
SA waters.
Thanks!
Christine
Christine (Nelson) Hall
Environmental Engineer
Division of Energy, Mineral and Land Resources — State Stormwater Program
Department of Environmental Quality
910 796 7215 office
910 796 7335 direct
[e-mail]
127 Cardinal Drive Ext.
Wilmington, NC 28405
Email correspondEnce to wid from this address is subject to the
thr_•rth .Carolina Public Records Law and may be discicsed to third parties.
From: Weaver, Cameron
Sent: Friday, January 15, 2016 9:14 AM
To: Hall, Christine <[e-mail]>
Subject: FW: Surf City K-8
Cameron Weaver
Environmental Assistance Coordinator -Wilmington Regional Office
NCDEQ-Division of Environmental Assistance and Customer Service
127 Cardinal Drive Ext.
Wilmington, NC 28405
910-796-7303
NCDEQ Website: http://Portal.ncdenr.org/web/guest
DEACS Website: http:%/Portal.ncdenr.org/web/deao/

E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.
From: Robert Balland [ma ilto:[e-mail]
Sent: Thursday, January 14, 2016 4:57 PM
To: Weaver, Cameron
Subject: FW: Surf City K-8
See attached.
From: Gretchen Merix
Sent: Thursday, January 14, 2016 3:54 PM
To: Robert Balland <[e-mail]>
Subject: Surf City K-8
Cameron called and said he needs a quad with the 32 mile circle before he can schedule your meeting.
Gretchen Merix, E.I.
Paramounte Engineering, Inc
5911 Oleander Drive, Suite 201
Wilmington, NC 28403
v: 910.791.6707
f: 910.791.6760
w: http://www.paramounte-eng.com

For DENR Use ONLY
Renewer.
A North Carolina Department of Environment and soixnt:
Natural Resources
NCDENR Request for Express Permit Review rme:
Confirm:
FILL -Ids all the information below and CHECK the Permit(s) you are requesting for express review. Call and Email the completed form to the
Pennit Coordinator along with a completed DETAILED narrative, site clan (PDF file) and vicinity mac (same items expected In the application
c%a a of the project location. Piense include this form in the application package. R'
• Asheville Region Alison Davidson 828-296-4698;alison.davidsono-ncdenr.00v
• Fayetteville or Raleigh Region -David Lee 919-7914203; david lee6mcdenr aov
• Mooresville & Winston Salem Region - Patrick Grogan 704-235-2107 ornatrick.orosranC-ncdenroov
• Washington Region -Lyn Hardison 252-948-3842 or ivn.hardisonCcbncdenrcov
• Wilmington Region -Janet Russell 910-796-7302 or ianet.russe►lamcdenr coy
• Wilmington Region -Cameron Weaver 910-796-7303 or cameron.weaverOncdenn-gov
NOTE., Project application received after 12 noon will be stamped in the following work day.
Project Name: SURF CITY K-8 SCHOOL County: FENDER
Applicant: KENNETH FULLER Company: PENDER COUNTY SCHOOLS
Address: 925 PENDERLEA HWY. City: BURGAW, State: NC Zip: 28425-_
Phone: [phone], Fax: [phone]. Email: kenneth [e-mail]
related to this Prolect
SW
SW
SW
NPDES _
NPDES
WQ
IINQ
E&S
E&S
Other
Physical Location:SHEPARDS DRIVE
Project Drains into BECKY'S CRK, COUNTY LINE BRNCH waters - Water classification SA. HQW (for classification see-
httD://Dortal.ncdenr.ora/web/wa/Ds/csu/classifications)
Project Located in CAPE FEAR River Basin. Is project draining to class ORW waters? N, within % mile and draining to class SA waters Y or within 1 mile
and draining to class HQW waters? Y
Engineer/Consultant: ROB BALLAND, PE Company: PARAMOUNTE ENGINEERING, INC I
Address: 5911 OLEANDER DRIVE, STE 201 City: WILMINGTON, State: NC Zip: 28403- I t I �Phone: [phone]. Fax: [phone]Email: [e-mail] ,
PLEASE PROVIDE ESThI ATED INVESTMENT AND EXPECTED EI1','PLOYMENT, IF AVAILAB► 2 ClV co P}.
$ # JOBS ULM 3 M l�
SEXTIO1,11 ONE: REQUESTING A SCOPING EEETING ONLY
® Scoping Meeting ONLY ® DWQ, ❑ DCM, ❑ DLR, ❑ OTHER: 404-0
SECTION! TWO: CHECK ONLY THE PROGRAMS YOU ARE REQUESTING FOR EXPRESS foc-R�IITTING
❑ 401 Unit ❑ Stream Origin Determination: _ # of stream calls - Please attach TOPO map marking the areas in questions
❑ intermittent(Perennial Determination: _ # of stream calls - Please attach TOPO map marking the areas in questions
❑ 401 Water Quality Certification ❑ Isolated Wetland (_linear ft or _acres)
❑ Riparian Buffer Authorization ❑ Minor Variance ❑ Major General Variance
® State Stomtwater ❑ General ❑ SFR, ❑ SFR < 1 ac. ❑ Bkhd & Bt Rmp, ❑ Clear & Grub, ❑ Utility ❑ Other
❑ Low Density ❑ Low Density -Curb & Gutter _ # Curb Outlet Swales ❑ Off -site [SW (Provide permit #)]
❑ High Density -Detention Pond _ # Treatment Systems ® High Density -Infiltration 1 #Treatment Systems
ElHigh Density -Bio-Retention _ # Treatment Systems El High Density -SW Wetlands _ # Treatment Systems
El High Density -Other _ # Treatment Systems / ❑ MOD:❑ Major El Minor [I Plan Revision ❑ Redev. Exclusion SW (Provide permit #)
❑ Coastal Management ❑ Excavation & Fill ❑ Bridges & Culverts ❑ Structures Information
❑ Upland Development ❑ Marina Development ❑ Urban Waterfront
❑ Land Quality ❑ Erosion and Sedimentation Control Plan with 0 acres to be disturbed.(CK # (for DENR use))
SECTION THREE - PLEASE CHECK ALL THAT IS APPLICABLE TO YOUR PROJECT (for both scoping and express meeting reguesti
Wetlands on Site ® Yes ❑ No Buffer Impacts: ® No ❑ YES: —acre(s)
Wetlands Delineation has been completed: E9 Yes ❑ No Isolated wetland on Property ❑ Yes E9 No
US ACOE Approval of Delineation completed: ® Yes ❑ No 404 Application in Process w/ US ACOE: ® Yes ❑ No Permit
Received from US ACOE ❑ Yes ® No
---- _ -- --- - - --._._..._.__.... - - ----- — ---- - - - -- - --- _ For LYENR use c i1;
Fee Split for multiple permits: (Check # 1 Total Faa Amnunt S
SUBMITTAL DATES
Fee
I SUBMITTAL DATES
Fee
CAMA
$
Variance (❑ Ma); ❑ Min)
$
SW (❑ HD, ❑ LID, ❑ Gen)
$
401:
$
LQS
$
Stream Deter,_
$
NCDENR EXPRESS October 2013

Surf City K-8 School
Express Stormwater Narrative
January 2016
Project Narrative:
Pender County Schools is proposing to construct a new K 8 School with associated parking,
sidewalks, and recreational facilities on an 84.92 acre parcel of land located in the southeast
portion of Pender County near Surf City. The parcel is further identified by Pender County
Parcel Identification Number#: 4226-92-2047-0000.
We are anticipating that this will be a low density project. The project is within two drainage
basins, Becky's Creek and County Line Branch, each with a stream classification of SA, HQW.
We believe that the portion of the property that drains to Becky's Creek is within 1h mile and
draining to the creek, therefore; we are requesting that portion of the project only has 12%
impervious area draining to Becky's Creek. The other portion of the site drains to County Line
Branch. Vjg-beIjQ�e this portion of the project is more than V2 mile from the branch and
therefore are requesting 24% impervious. The following is a breakdown of the areas draining to
each basin and the requested low density impervious areas:
• DA-1 (Becky's Creek) 33.3 acres 12% = 4.0 acres (174,066 sf)
• DA-2 (County Line Branch) 51.6 acres 24% =12.4 acres (539,447 sf)
The storm water runoff .from this project will be conveyed within the limits listed above via
swales and outfall to surrounding wetlands which drain to each outfall.

40
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PRELIMINARY DESIGN - NOT RELEASED FOR CONSTRUCTION
PRE DEVELOPMENT
DRAINAGE AREA MAP
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SURPCITYK-B
PENDERCOUNTY
NORTH CAROLINA
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