SW8970128_HISTORICAL FILE_20050307

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 '�:'11 klF
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
2Uo5 5'60 1
YYYYMMDD
I

�ATrF9
I ■ J1-7
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
March 7. 2005
Mr. Ron Core, Vice Chancellor
UNC-Wilmington
601 College Road
Wilmington, NC 28403
Subject: Stormwater Permit No. SW8 970128 Modification
UNC-W Honors, International & Privatized Housing
High Density Project
New Hanover County
Dear Mr. Core
The Wilmington Regional Office received a complete modified Stormwater Management
Permit Application for UNC-W Honors, International & Privatized Housing on March 7, 2005.
Staff review of the plans and specifications has determined that the project, as proposed, will
comply with the Stormwater Regulations set forth in Title 15A NCAC 21-1.1000. We are
forwarding Permit No. SW8 970128 Mod., dated March 7, 2005, for the construction of the
subject project.
This permit supercedes all previously issued stormwater permits, and shall be effective from
the date of issuance until March 7, 2015, and shall be subject to the conditions and limitations
as specified therein. Please pay special attention to the Operation and Maintenance
requirements in this permit. Failure to establish an adequate system for operation and
maintenance of the stormwater management system will result in future compliance problems.
If any parts, requirements, or limitations contained in this permit are unacceptable, you have
the right to request an adjudicatory hearing upon written request within sixty (60) days
following receipt of this permit. This request must be in the form of a written petition,
conforming to Chapter 150B of the North Carolina General Statutes, and filed with the Office of
Administrative Hearings, P.O. Drawer 27447, Raleigh, NC 27611-7447. Unless such demands
are made this permit shall be final and binding.
If you have any questions, or need additional information concerning this matter, please
contact Linda Lewis, or me at [phone].
Sincerejy,
Edward Beck
Acting Regional Supervisor
Surface Water Protection Section
ENB/arl: S:\WQS\STORMWAT\PERMIT\970128.mar05
cc: Stephen Thomas, P.E., Stewart Engineering
Tony Roberts, New Hanover County Building Inspections
City of Wilmington Stormwater Services
Linda Lewis
[W ilriiingtonReg iona]=Office?
Central Files
North Carolina Division of Water Quality 127 Cardinal Drive Extension Phone [phone] Customer Servicel-877-623-6748
Wilmington Regional Office Wilmington, NO 28405-3845 FAX [phone] Internet: h2o.ennstate.nc,us One
ivOrtt1C3C011na
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An Equal OpportunitylAffirma6ve Action Employer— SOe/ Recycledll0%Post Consumer Paper Natutalllf

State Stormwater Management Systems
Permit No. SW8 970128 Modification
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
STATE STORMWATER MANAGEMENT PERMIT
HIGH DENSITY DEVELOPMENT
In accordance with the provisions of Article 21 of Chapter 143, General Statutes of
North Carolina as amended, and other applicable Laws, Rules, and Regulations
PERMISSION IS HEREBY GRANTED TO
Ron Core and UNC-W
UNC-W Honors, International & Privatized Housing
New Hanover County
FOR THE
construction, operation and maintenance of a wet detention pond in compliance with
the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwaterrules')
and the approved stormwater management plans and specifications and other
supporting data as attached and on file with and approved by the Division of Water
Quality and considered a part of this permit.
This permit shall be effective from the date of issuance until March 7, 2015, and shall
be subject to the following specified conditions and limitations:
1. DESIGN STANDARDS
This permit is effective only with respect to the nature and volume of stormwater
described in the application and other supporting data.
2. This stormwater system has been approved for the management of stormwater
runoff as described in Section 1.7 on page 3 of this permit. The stormwater
control has been designed to handle the runoff from 398,807 square feet of
impervious area.
3. The tract will be limited to the amount of built -upon area indicated on page 3 of
this permit, and per approved plans.
4. All stormwater collection and treatment systems must be located per the
approved plan.
5. The runoff from all built -upon area within the permitted drainage area of this
project must be directed into the permitted stormwater control system.
6. The amount of built -upon area for this pond previously approved under the 1997
permit, has been increased to account for the Privatized Housing project.
Page 2 of 7

State Stormwater Management Systems
Permit No. SW8 970128 Modification
7. The following design criteria have been provided in the wet detention pond and
must
be maintained at design condition:
a.
Drainage Area, acres:
28.128
Onsite, ft :
1,202,757
Offsite, ft2:
22,498
b.
Total Impervious Surfaces, ft2:
398,807
C.
Design Storm, inches:
1
d.
Pond Depth, feet:
6.0
e.
TSS removal efficiency:
90%
f.
Permanent Pool Elevation, FMSL:
26.0
g.
Permanent Pool Surface Area, ft2:
52,127
h.
Permitted Storage Volume, ft3:
79,638
i.
Temporary Storage Elevation, FMSL:
27.4
j.
Controlling Orifice:
3" O pipe
k.
Permitted Forebay Volume, ft3:
58,631
I.
Receiving Stream/River Basin:
Bradley Creek / Cape Fear
M.
Stream Index Number:
CPF24 18-87-24-4-(1)
n.
Classification of Water Body:
"SC HQW #"
II. SCHEDULE OF COMPLIANCE
1. The stormwater management system shall be constructed in its entirety,
vegetated and operational for its intended use prior to the construction of any
built -upon surface.
2. During construction, erosion shall be kept to a minimum and any eroded areas of
the system will be repaired immediately.
3. The permittee shall at all times provide the operation and maintenance
necessary to assure the permitted stormwater system functions at optimum
efficiency. The approved Operation and Maintenance Plan must be followed in
its entirety and maintenance must occur at the scheduled intervals including, but
not limited to:
a. Semiannual scheduled inspections (every 6 months).
b. Sediment removal.
C. Mowing and revegetation of slopes and the vegetated filter.
d. Immediate repair of eroded areas.
e. Maintenance of all slopes in accordance with approved plans and
specifications.
f. Debris removal and unclogging of outlet structure, orifice device, flow
spreader, catch basins and piping.
g. Access to the outlet structure must be available at all times.
Page 3 of 7

State Stormwater Management Systems
Permit No. SW8 970128 Modification
4. Records of maintenance activities must be kept and made available upon
request to authorized personnel of DWQ. The records will indicate the date,
activity, name of person performing the work and what actions were taken.
5. Decorative spray fountains will be allowed in the stormwater treatment system,
subject to the following criteria:
a. The fountain must draw its water from less than 2' below the permanent
pool surface.
b. Separated units, where the nozzle, pump and intake are connected by
tubing, may be used only if they draw water from the surface in the
deepest part of the pond.
c. The falling water from the fountain must be centered in the pond, away
from the shoreline.
d. The maximum horsepower for a fountain in this pond is 3/4 horsepower.
6. The facilities shall be constructed as shown on the approved plans. This permit
shall become voidable unless the facilities are constructed in accordance with
the conditions of this permit, the approved plans and specifications, and other
supporting data.
7. Upon completion of construction, prior to issuance of a Certificate of Occupancy,
and prior to operation of this permitted facility, a certification must be received
from an appropriate designer for the system installed certifying that the permitted
facility has been installed in accordance with this permit, the approved plans and
specifications, and other supporting documentation. Any deviations from the
approved plans and specifications must be noted on the Certification. A
modification may be required for those deviations.
8. If the stormwater system was used as an Erosion Control device, it must be
restored to design condition prior to operation as a stormwater treatment device,
and prior to occupancy of the facility.
9. Access to the stormwater facilities shall be maintained via appropriate
easements at all times.
10. The permittee shall submit to the Director and shall have received approval for
revised plans, specifications, and calculations prior to construction, for any
modification to the approved plans, including, but not limited to, those listed
below:
a. Any revision to any item shown on the approved plans, including the
stormwater management measures, built -upon area, details, etc.
b. Project name change.
C. Transfer of ownership.
d. Redesign or addition to the approved amount of built -upon area or to the
drainage area.
e. Further subdivision, acquisition, lease or sale of all or part of the project
area. The project area is defined as all property owned by the permittee,
for which Sedimentation and Erosion Control Plan approval or a CAMA
Major permit was sought.
f. Filling in, altering, or piping of any vegetative conveyance shown on the
approved plan.
11. The permittee shall submit final site layout and grading plans for any permitted
future areas shown on the approved plans, prior to construction.
12. A copy of the approved plans and specifications shall be maintained on file by
the Permittee for a minimum of ten years from the date of the completion of
construction.
Page 4 of 7

State Stormwater Management Systems
Permit No. SW8 970128 Modification
13. The Director may notify the permittee when the permitted site does not meet one
or more of the minimum requirements of the permit. Within the time frame
specified in the notice, the permittee shall submit a written time schedule to the
Director for modifying the site to meet minimum requirements. The permittee
shall provide copies of revised plans and certification in writing to the Director
that the changes have been. made.
III. GENERAL CONDITIONS
This permit is not transferable except after notice to and approval by the Director.
In the event of a change of ownership, or a name change, the permittee must
submit a formal permit transfer request to the Division of Water Quality,
accompanied by a completed name/ownership change form, documentation
from the parties involved, and other supporting materials as may be appropriate.
The approval of this request will be considered on its merits and may or may not
be approved. The permittee is responsible for compliance with all permit
conditions until such time as the Division approves the transfer request.
2. Failure to abide by the conditions and limitations contained in this permit may
subject the Permittee to enforcement action by the Division of Water Quality, in
accordance with North Carolina General Statute 143-215.6A to 143-215.6C.
3. The issuance of this permit does not preclude the Permittee from complying with
any and all statutes, rules, regulations, or ordinances, which may be imposed by
other government agencies (local, state, and federal) having jurisdiction.
4. In the event that the facilities fail to perform satisfactorily, including the creation
of nuisance conditions, the Permittee shall take immediate corrective action,
including those as may be required by this Division, such as the construction of
additional or replacement stormwater management systems.
5. The permittee grants DENR Staff permission to enter the property during normal
business hours for the purpose of inspecting all components of the permitted
stormwater management facility.
6. The permit may be modified, revoked and reissued or terminated for cause. The
filing of a request for a permit modification, revocation and reissuance or
termination does not stay any permit condition.
7. Unless specified elsewhere, permanent seeding requirements for the stormwater
control must follow the guidelines established in the North Carolina Erosion and
Sediment Control Planning and Design Manual.
8. Approved plans and specifications for this project are incorporated by reference
and are enforceable parts of the permit.
9. The permittee shall notify the Division any name, ownership or mailing address
changes within 30 days.
Permit issued this the 7th day of March 2005.
NORTH CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
Division of Water Quality
By Authority of the Environmental Management Commission
Page 5 of 7

_..„ ..: €;fir.`:.,- _ '�-"'-=ofr'OFF.ICE=L9SE`ONLYr""
.:.,.-:.: .••�-: : •-:,, �„-:„- ::--z:_-•:'- Y." ;it
Date Re"..•
ceived
Fee Paid
Number
Permit Number
01. Z5` 05-
#g000, vo
ISw 9q-7012% /-00
mod.. 3-4- &Y)5
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for use as an original
I. GENERAL INFORMATION
1. Applicants name (specify the name of the corporation, individual, etc. who owns the project):
UNIVE/kSITY- Cl- A0AT&+ 6i4M4MA a �It�MI Ntr TON
2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance):
3. Mailing Address for person listed in item 2 above: q
&C k t.OLI-aC'e RoAo
City: State: PC Zip: A5 w 3
Telephone Number:
4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans,
specifications, letters, operation and maintenance agreements, etc.):
UNCW 200[0 PAIVA-riace3 liv wz IvTCRNMT/owlAL 14owwf-t (40�V&S 4sc"JG
5. Location of Project (street address):
UNC w CRnPuS t (9U1 �ou Er.G /wap
City: WILn1,1VTON County: 111Et✓ �-i "oveA,
6. Directions to project (from nearest major intersection): 6I
LOC47-CO 01-i CJN ( L"' C+ry 9 Sri o4-L c) C.J�aNEti :�At i
7. Latitude: 1623630 I Longitude: 3 ?,To `f 10 of project
(w65 8V1A1#Da3�
8. Contact person who can answer questions about the project
Name:bAtAA 4or¢r7'eI S7dgFe�*1T CNri, Telephone Number: ( C71°) ) 3b0-$7S0 e'-P IGC
II. PERMIT INFORMATION:
1. Specify whether project is (check one):
New
Form SWU-101 Version3.99 Page l of
Renewal _ Modification

2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
existing permit number SW 6q 701 Z9 and its issue date (if known)
3. Specify the type of project (check one):
_Low Density High Density _Redevelop General Permit Other
4. Additional Project Requirements (check applicable blanks):
_CAMA Major ✓Sedimentation/Erosion Control _404/401 Permit _NPDES Stormwater
Information on required state permits can be obtained by contacting the Customer Service Center at
1-877-623-6748.
III. PROJECT INFORMATION
1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative
(one to two pages) describing stormwater management for the project .
S7W-r%LOAT46R kMPFF AtE L^0cL LTEQ 6Y A Sf)',uES OF 6A7Cµ
84Sl VS A"4 PIPCio 7c7 'THE 41E7eu71oo7 PoN6.
2. Stormwater runoff from this project drains to the
(,4PLE
FGAtL
River basin.
3. Total Project Area: ZS. 1 Z(3 acres
4.
Project Built Upon Area:
3 Z -49-
5. How many drainage areas does the project have? I
6. Complete the following information for each drainage area. If there are more than two drainage areas in the
project, attach an additional sheet with the information for each area provided in the same format as below.
Basin Information, _
- Drainage Area I - -
-_ Drainage Area 2
Receiving Stream Name
&AOt-FIr Coe E %Rir�vTaa
Receiving Stream Class
SC+4 [J t,>
Drainage Area
28-129 AC
Existing Impervious' Area
.2, 3 (e 2 AC
Proposed Impervious"Area
Cl. I SS .4C.
% Impervious{ Area (total)
,33, S G/d
Impervious` Surface Area
Drainage Area 1
Drainage Area 2
On -site Buildings
IOZ03& st
On -site Streets
8100 64�t
On -site Parking
/00220 St
On -site Sidewalks
�Sr753 S-�
Other on -site
Off -site
2 2 98 s�
Total:
Total:
fi Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas,
sidewalks, gravel areas, etc.
Form SWU-101 Version 3.99 Page 2 of 4

7. How was the off -site impervious area listed above derived? Aol,*A a.,ecs c.. Ev c. -a c u 6sod
IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS
The following italicized deed restrictions and protective covenants are required to be recorded for all
subdivisions, outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a table
listing each lot number, size and the allowable built -upon area for each lot must be provided as an attachment.
1. The following covenants are intended to ensure ongoing compliance with state stonnwater management permit number
as issued by the Division of Water Quality. These covenants may not be
changed or deleted without the consent of the State.
2. No more than I square feet of any lot shall be covered by structures or impervious materials.
Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include wood
decking or the water surface of swimming pools.
3. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossings.
4. Built -upon area in excess of the permitted amount requires a state stormwater management permit modification prior to
construction.
5. All permitted runoff from outparcels or future development shall be directed into the permitted stormwater control
system. These connections to the stormwater control system shall be performed in a manner that maintains the integrity
and performance of the system as permitted.
By your signature below, you certify that the recorded deed restrictions and protective covenants for this project
shall include all the applicable items required above, that the covenants will be binding on all parties and persons
claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted
without concurrence from the State, and that they will be recorded prior to the sale of any lot.
V. SUPPLEMENT FORMS
The applicable state stormwater management permit supplement form(s) listed below must be submitted for each
BMP specified for this project. Contact the Stormwater and General Permits Unit at [phone] for the status
and availability of these forms.
Form SWU-102
Wet Detention Basin Supplement
Form SWU-103
Infiltration Basin Supplement
Form SWU-104
Low Density Supplement
Form SWU-105
Curb Outlet System Supplement
Form SWU-106
Off -Site System Supplement
Form SWU-107
Underground Infiltration Trench Supplement
Form SWU-108
Neuse River Basin Supplement
Form SWU-109
Innovative Best Management Practice Supplement
Form SWU-101 Version 3.99 Page 3 of 4

VI. SUBMITTAL REQUIREMENTS
Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ).
A complete package includes all of the items listed below. The complete application package should be
submitted to the appropriate DWQ Regional Office.
Please indicate that you have provided the following required information by initialing in the space provided
next to each item.
Initials
• Original and one copy of the Stormwater Management Permit Application Form 101n
• One copy of the applicable Supplement Form(s) for each BMP 01--3
• Permit application processing fee of $420 (payable to NCDENR) d03
• Detailed narrative description of stormwater treatment/management rAol!s
• Two copies of plans and specifications, including: 4z"6
- Development/Project name
- Engineer and firm
-Legend
- North arrow
- Scale
- Revision number & date
- Mean high water line
- Dimensioned property/project boundary
- Location map with named streets or NCSR numbers
- Original contours, proposed contours, spot elevations, finished floor elevations
- Details of roads, drainage features, collection systems, and stormwater control measures
- Wetlands delineated, or a note on plans that none exist
- Existing drainage (including off -site), drainage easements, pipe sizes, runoff calculations
- Drainage areas delineated
- Vegetated buffers (where required)
VII. AGENT AUTHORIZATION
If you wish to designate authority to another individual or firm so that they may provide information on your
behalf, please complete this section.
Designated agent (individual or firm):
Mailing Address:
City: State: Zip:
Phone: _ ) Fax: ( )
VITT. APPLICANT'S CERTIFICATION
I, (print or type name of person listed in General Information, item 2) Ronald .1 . Core
certify that the information included on this permit application form is, to the best of my knowledge, correct and
that the project will be constructed in conformance with the approved plans, that the required deed restrictions
and protective cove�ss�will be recorded, and that the proposed project complies with the requirements of 15A
NCAC 2H .1000. i , n ----7
Date:
Form SWU-101 Version 3.99 Page 4 of 4

STEWARTbob
ENGINEERING
RECEIVED
MAR 0 7 2005
BY:
LETTER OF TRANSMITTAL
TO: NCDENR-Wilmington Regional Office DATE: March 04, 2005
127 Cardinal Drive Extension ATTN: Linda Lewis
Wilmington, NC 28405-3845
WE ARE SENDING YOU:
_ SHOP DRAWINGS PRINTS
SPECIFICATIONS X COPY OF LETTER
COPIES DATE DESCRIPTION
JOB #: C4021
RE: UNCW Privatized Housing— Express Review -
Resubmitttal
VIA: Standard Mail
X PLANS SAMPLES X OTHER
CHANGE ORDER DISKETTES
2
3104105
Revised Civil Plans (ones that changed from previous submittal — C7.00
2
3104105
Revised Draw Down Calculations
1
3104105
Response to comments letter
THESE ARE TRANSMITTED AS INDICATED BELOW:
X For Approval Approved as submitted Resubmit copies for approval
For Your Use Approved as noted
As Requested Returned for corrections
For Review & Comment Returned after loan to us
REMARKS:
Ms. Lewis,
Attached is our resubmittal for the above project based upon your comments from your March V email.
Thank you for your assistance and please feel free to call if you have any questions.
- David Boyette, El
COPY TO:
SIGNED: '�5a� /fl/s �
David Boyette, El
260 Town Hall Dr., Suite C, Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com

Stormwater & Erosion Control Calcs
For the proposed
UNCW 2006 Privatized Housing
Durham, North Carolina
Prepared for RECEIVED
Clark Nexsen
Prepared By
Stewart Engineering, Inc.
his
�
s ra ww It
ENGINEERING
January 24,2005
Revised January 28, 2005
Revised March 4, 2005
MAR 0 7 2005
PROJ # �i T70I2$ �&P
i
i
a'd ZSLBOBEGIG uui 2uivaau12u3 quemagS
dEE:SO SO LO JeW

7
Stormwater & Erosion Control Calculations
For
UNCW 2006 Privatized Housing
Wilmington, North Carolina
Prepared for:
Clark Nexsen
Prepared by:
Stewart Engineering, Inc.
260 Town Hall Drive, Suite C
Morrisville, NC
919.380.8750
SEI Project No. C4021
January 24, 2005
Revised January 28, 2005

STORMtiVATER MANAGEMENT NARRATIVE
UNCW 2006 PRIVATIZED HOUSING
WIUMINGTON, NORTH CAROLINA
PROJECT SUMMARY
The proposed UNCW 2006 Privatized Housing project is comprised of six apartment buildings, a
community building and associated parking areas and walkways. The project is located on the
eastern boundary of the UNCW campus in proximity to Wagner Hall and the Honors-
Intemational-Comerstone quad. As part of this project we are requesting a revision to
Stormwater Permit #SW8970128.
The existing site is a wooded area of which the majority drains to an existing stormwater
detention pond. The detention pond and the portion of the existing site that bypass the pond
dram to a tributary of Bradley Creek. As part of this project the existing pond will be expanded
and the runoff from the proposed site will be directed to it through a network of inlets and pipes.
Although the existing pond is sized adequately to handle the additional drainage and build upon
areas, the pond will be expanded in order to meet City of Wilmington quantity control standards.
An improvement will be made to the emergency spillway of the existing pond as the spillway is
inadequate in the existing condition and erodes regularly. Currently, the spillway elevation is
below the 2-yr water surface elevation and approximately 15' wide. The spillway elevation will
be raised to the elevation of the 10-yr storm and its length increased to safely pass the 100-yr
rainfall event without overtopping the dam. An earthen baffle will also be added to the pond to
increase the flow path and travel time through the pond to ensure that a length to width ratio of
3:1 is met. The Torbay will be expanded as well to meet the 20% of total volume requirement
Please see the attached proposed drainage area map, wet detention pond sizing, and draw down
time calculations.

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{ o it ;{!f�!(o�i `�t\ �} ( \\ji �`1 `\ 1\.... j'-." C"-� \ zF .•.
(15
PROPOSED DRAINAGE J/ f'^ I i Sao.. i• C \ \silt �..� ( ^ 7 N,
L AREA = h8. f28
'��� (' it lllll Iill,lllJ 1111(I LI'illt.1111id� •I II IIIIIIifI177 i'i7 t(I III IIII,I w�/-.� — / �} .f`-�•� %"�
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v .- IJ�nuu I id"
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1
t v� rI{t r ,{{ 9•, ern{
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11101,11
03
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r,
Z
W a
W Ia
N i<�
SOLE
rr;
200GRAPHI0
200
IN FEET
1 inch = 200 ft.

A
S T E W A A T
ENGINEERING
Wet Detention Pond Sizing
(for 90% TSS removal)
Project UNC-W University Housing
Project No. C4021
Date 28-Feb-05
STRUCTURAL
TRANSPORTATION
CIVIL
Required Surface Area
Required Storage for 1st inch of runoff
Total Drainage Area =
28.128 ac
Simple Method
Total Impervious Area =
9.155 ac
Percent Impervious =
33%
Rv = 0.05 + 0.009(I)
1 = % impervious = 33%
Perm. Pool Depth =
6 ft
SA/DA Ratio (Table 1.1) =
1.75
Rv = 0.34 in
Surface Area Required =
21442 sf
Volume = 35015 cf
=
0.49 ae
Surface Area Provided = 1.2 ae Volume Provided = 96777 cf
Calculation Methods are taken from NCDENR Stormwater Best Management Practices manual, April 1999
260 Town Hall Drive, Suite C, Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com

S T E W A R T
ENGINEERING
Water Quality Drawdown Calculations - Wet Pond
(1 st inch of rainfall)
'Simple Method'
Total Drainage Area =
28.128 ac
Drawdown Pipe
Total Impervious Area =
9.155 ac
Invert =
26 ft
Percent Impervious =
33%
Diameter =
4 in
Rv = 0.05 + 0.009(I)
b
1.07
I = % impervious =
33%
Ks
56557
Rv =
0.34 in
Req' Depth
0.65 ft
Runoff Vol. = 35,015 cf
Actual Depth
1.40 ft
Pond Invert = 20.0 ft
Increm.
Drawdown
Total
Elevation
Storage
Storage
Outflow
Time
Time
(ft)
(cf)
(cf)
(cfs)
(hr)
(days)
27.40
481465
0
0.466
0.000
0.00
27.30
474506
6952
0.447
4.424
0.18
27.20
467554
6945
0.426
4.639
0.38
27.10
460609
6938
0.405
4.890
0.58
27.00
453671
6931
0.383
5.188
0.80
26.90
446740
6924
0.359
5.550
1.03
26.80
439816
6917
0.334
6.002
1.28
26.70
432899
6910
0.306
6.590
1.55
26.60
425989
6903
0.276
7.398
1.86
26.50
419086
6895
0.242
8.611
2.22
26.40
412191
6888
0.203
8.557
2.58
26.30
405304
6880
0.245
8.606
2.94
26.20
398424
6872
0.200
11.203
3.40
26.10
391552
6864
0.141
26.929
4.52
26.00
384688
6856
0.000
0.000
4.52
Drawdown Time = 4.52 days
�d
STRUCTURAL
TRANSPORTATION
CIVIL
'Simple Method' taken from NCDWQ Stormwater - Best Management Practices Manual, November 1995

STRUCTURAL
TRANSPORTATION
CIVIL
5 T E WART Volume Calculations
ENGINEERING
Forbay Volume
Contour
(ft)
Area
(ft2)
Incr
Vol
(ft3)
Accum
Vol
(ft3)
20
6319
0
0
21
7355
6837
6837
22
8466
7911
14748
23
9654
9060
23808
24
1 10915
1 10285
1 34092
25
12251
11583
1 45675
26
13660
12956
58631
27
16147
14904
73534
Total Pond Volume
Contour
(ft)
Area
(ft2)
Incr
Vol
(ft3)
Accum
Vol
(ft3)
20
29839
0
0
21
33164
31502
31502
22
36645
34905
66406
23
40283
38464
104870
24
1 44076
1 42180
147050
25
48024
46050
193100
26
52127
50076
243175
27
61641
56884
300059
Forbay Vol ( 26.0') = 58631 cf
Total Vol (26.0')= 243175 cf
Forbay equals 24.1 % of total volume.
MAR 0 3 1005
DWQ
PROJ# f)WlT 970
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OPMEMM
STRUCTURAL
TRANSPORTATION
A CIVIL
S T E W A N T Volume Calculations
ENGINEERING
Forbay Volume
Contour
(ft)
Area
(ft2)
Incr
Vol
(ft3)
Accum
Vol
(fr3)
20
6319
0
0
21
7355
6837
6837
22
8466
7911
14748
23
9654
9060
23808
24
10915
10285
34092
25
12251
11583
45675
26
13660
12956
58631
27
16147
14904
73534
Total Pond Volume
Contour
(ft)
Area
(ft2)
Incr
Vol
(ft3)
Accum
Vol
(171:3)
20
29839
0
0
21
33164
31502
31502
22
36645
34905
66406
23
40283
38464
104870
24
44076
42180
147050
25
48024
46050
193100
26
52127
50076
243175
27
61641
56884
300059
28
64654
63148
363207
Forbay Vol ( 26.0') = 58631 cf
Total Vol (26.0')= 243175 of
Forbay equals 24.1% of total volume.

S W 8 970128
Subject: SW8 970128
From: Linda Lewis <[e-mail]>
Date: Thu, 03 Mar 2005 18:22:14 -0500
To: [e-mail]
Steve:
Now that you have provided the surface area at elevation 27, I was able to run my
spreadsheet completely, and determine that the 4" orifice is too large. I know that
a 4" orifice was I am unable to decipher how you came up with 4.52 days as a
drawdown time. I use the standard orifice equation to determine the orifice size
based on flowrates for a 2-day drawdown (35016 / 172800 = .203 cfs) and a 5 day
drawdown (35016 /432000 =.081 cfs). Then using the average head between the
permanent pool and the next available outlet (.62 ft), and I calculate the 2 day
(7.72 sq. inches) and 5 day (3.09 sq. inches) areas for the orifices. The area of a
4" orifice is over 12.5 sq. in. As long as the area of the orifice you pick is
between those two areas, it should work fine.
Linda
1 of 1 3/3/2005 6:22 PM

RE: UNCW Honors, International & Privatized Housing SW8 970128
Subject: RE: UNCW Honors, International & Privatized Housing SW8 970128
From: "Stephen Thomas" <[e-mail]>
Date: Thu, 3 Mar 2005 17:08:11 -0500
To: "Linda Lewis" <[e-mail]>
CC: "Shuford, Charles" <[e-mail]>, "David Boyette" <[e-mail]>
Linda,
Attached is a PDF of the contour areas for the pond with your requested
amendments. Please review and notify us if any additional information
is needed. Additionally, Mr. Ed Shuford of UNCW Facilities Planning
Dept. will be delivering new applications to your office for the permit
(signed by Ron Core, Vice -Chancellor) tomorrow. If this is not
sufficient, please give me a phone call or otherwise contact me to let
me know what we can do to complete this permitting process. Again, I
appreciate your help and attention.
Sincerely,
Steve Thomas
Steve Thomas, PE
Civil Project Manager
Stewart Engineering, Inc.
[phone] - office
[phone] - fax
[phone] - cell
www.stewart-eng.com
"Committed to Engineering Excellence,
Employee Development, and Personal Client
Services through Innovative Solutions."
-----Original Message -----
From: Linda Lewis [mailto:[e-mail]]
Sent: Thursday, March 03, 2005 10:01 AM
To: Stephen Thomas
Subject: UNCW Honors, International a Privatized Housing SW8 970128
Steve:
The volume calculations for the pond and forebay only go up to elevation
26 (permanent pool) . I need for you to add the area and volume at
elevation 27 (or at 26.65) to support your claim that sufficient volume
has been provided at 26.65 to hold the 1" storm.
I also need a letter from the chancellor authorizing Mr. Freshwater to
sign the permit application on behalf of the University. The Physical
Plant may end up being charged with the responsibility of maintenance by
the permittee (the University), but the application needs to be signed
by a person who is authorized to subject the University to the financial
burden of the maintenance responsibilities under that permit.
Content -Description: Pond Contour Areas to
Contour Areas to NCDENR.PDF NCDENR.PDF
Content -Type: application/octet-stream
l of2
3/3/2005 5:47 PM

RE: UNCW Honors, International & Privatized Housing SW8 970128
I,
Content -Encoding: base64
2 of 2 3/3/2005 5:47 PM

A Sv\/2 q1 o IZ�
STORMWATER NARRATIVE
UNC Wilmington — Privatized Housing
Wilmington, North Carolina
EXECUTIVE SUMMARY
This Stormwater Narrative contains a drainage analysis of the referenced project.
Site Information
The project site is located in the rear of the campus of University of North Carolina at
Wilmington. The site may be accessed by entering the most northern entrance of campus via Randall
Drive from College Avenue. Follow Randall Drive to the rear of campus where the road ends. Turn right
onto Reynolds Drive. Turn left at the next road, Cahill Drive. Follow Cahill to the end of the road and
the project site is directly in front of this dead end.
At this time, the area has not been previously developed, and consists a mix of open area and
wooded area. The site is relatively flat, having an overall slope to the east / southeast averaging 1.5%.
In its observed condition, the majority of the stormwater runoff from the site tends to sheet flow
from west to east. A clear destination for the storm drainage is not readily discernable.
Proposed Improvements
The project proposes to construct six to seven apartment buildings having an approximate
footprint of I1,000 square feet. There will be parking surrounding the apartment buildings. A clubhouse
will be constructed as well. The project will disturb approximately 20 acres.
Proposed stormwater management will be facilitated by bioretention areas and the expansion of
an existing stormwater detention pond. The storm drainage will either sheet flow from the parking areas
into treatment swales, or will be collected in a storm drainage system which will discharge into the pond.
Design Requirements
Erosion and Sedimentation control measures shall be designed in accordance with 15A NCAC,
chapter 4 (NC Sedimentation Pollution Control Act of 1973).
Stormwater management measures shall be designed in accordance with stormwater management
regulations, as detailed in 15 NCAC 02B.0216 (Section #3.b.i.B) In accordance with the requirements,
the first 1 inch of rainfall shall be collected and infiltrated. The excess volume shall bypass across a
reinforced spillway.
Permits Required
A general Stormwater Permit will be obtained through North Carolina Department of
Environment and Natural Resources — Division of Water Quality. Concurrently, the City of
Wilmington will issue approval of the construction plans on the basis of no net increase in site
runoff in the 10-year design storm.

�
STEWART
ENGINEERING
LETTER OF TRANSMITTAL
TO: NCDENR-Wilmington Regional Office DATE: February 28, 2005
127 Cardinal Drive Extension ATTN: Linda Lewis
Wilmington, NC 28405-3845
WE ARE SENDING YOU:
SHOP DRAWINGS
SPECIFICATIONS
COPIES DATE
JOB #: C4021
RE: UNCW Privatized Housing— Express Review -
Resubmitttal
VIA: HAIL
PRINTS X PLANS SAMPLES X OTHER
X COPY OF LETTER ' CHANGE ORDER DISKETTES
DESCRIPTION
2
2/28105
Completed Application for Stormwater Permit Partial Original and copy)
2
2/28/05
Revised Civil Plans ones that changed from previous submittal
1
2128/05
Revised Stormwater & Erosion Control Calculations
1
2128✓05
Response to comments letter
THESE ARE TRANSMITTED AS INDICATED BELOW:
X For Approval Approved as submitted Resubmit copies for approval
For Your Use Approved as noted
As Requested Returned for corrections
For Review & Comment Returned after loan to us
REMARKS:
Ms. Lewis,
Attached is our resubmittal for the above project based upon your comments on February 25, 2005. Tom
Freshwater was chosen by the University to sign the financial responsibility due to his direct responsibility for
the maintenance of the pond. Mr. Ed Shuford with UNCW would be glad to discuss this matter with you if it
would help. His number is [phone]. Thank you for your assistance and please feel free to call if you
have any questions.
- Steve Thomas, PE FZECEIVF-D
LMAR 0 1 2005
BY:------
COPY TO: Peter Aranyi, AIA — Clark Nexsen SIGNED: 4�9
Ed Shuford — UNCW Facilities Steve Thomas, PE — Project Manager
260 Town Hall Dr., Suite C, Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com

By.MAR � 1 ?OOS
LETTER OF TRANSMITTAL
TO: NCDENR-Wilmington Regional Office DATE: February 25, 2005
127 Cardinal Drive Extension ATTN: Linda Lewis
Wilmington, NC 28405-3845
WE ARE SENDING YOU:
JOB #: C4021
RE: UNCW Privatized Housing— Express Review
VIA: Hand Delivery
SHOP DRAWINGS PRINTS X PLANS SAMPLES X OTHER
SPECIFICATIONS X COPY OF LETTER CHANGE ORDER DISKETTES
COPIES DATE DESCRIPTION
2
2/25/05
Completed Application for Stormwater Permit Original and copy
2
2/25/05
Civil Plans
1
2/25/05
Stormwater & Erosion Control Calculations
1
2/25/05
Drainage Ma
1
2/24/05
Completed Financial Responsibility Form
1
2/23/05
Check for $4,000.00
THESE ARE TRANSMITTED AS INDICATED BELOW:
X For Approval
For Your Use
As Requested
For Review & Comment
REMARKS:
Ms. Miller,
Approved as submitted
Approved as noted
Returned for corrections
Returned after loan to us
Resubmit copies for approval
Attached is our application for modification of the existing stormwater permit related to the above project
(SW8 97012a). Thank you and please feel free to call if you have any questions.
- Steve Thomas, PE
COPY TO: Peter Aranyi, AIA — Clark Nexsen SIGNED:
Ed Shuford — UNCW Facilities
PE — Project Manager
260 Town Hall Dr., Suite C, Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com

University of North Carolina at Wilmington
2006 Privatized Housing & Honors Housing & International Housing
Stormwater Permit Number: SW8970128 MOD
The following are the review comments and corrections for the above referenced plan:
Add a note on the plans referencing a list of approved wetland species to be used for the pond.
Response: This note has been added..
2. Indicate on the section A -A that a 6:1 slope starts at the elevation of the permanent pool and
running for at least 10'. Use a 3:1 slope minimum above the permanent pool. Add notes to this
effect on the plans.
Response: These notes have been added.
3. Need to use correct SADA ratio table for coastal regions of North Carolina.
Response: This table was used and the calculations have been revised accordingly.
4. Need to show a table giving the contour areas for both the pond forbay and the forbay and main
pond combined.
Response: These tables have been added to the calculations.
5. Show more clearly that the rectangular hole in the outlet structure will be grouted in after
installation of the drawdown pipe.
Response: A clarifying note has been added to the detail for the outlet structure.
6. Verify Tom Freshwater's authority to sign for responsibility for pond.
Response: After a discussion with Ed Shuford, Program Coordinator for the Office of
Facilities, we are confident that Mr. Freshwater is the person who most logically has
responsibility for the maintenance of the pond. It is his group that would be called in the event
of any malfunction or maintenance request. As the Physical Plant Director, Mr. Freshwater
has been given the authority to represent the University in all matters of this nature. Please
call Mr. Shuford if any further clarification is needed on this matter at [phone].
7. Add the longitude and latitude of the outlet structure to the application..
Response: This information has been added.
8. Revise calculations to estimate drawdown time using the full driving head which is acting on the
drawdown pipe when the highest elevation of water (27.40') occurs. This change will affect the
drawdown calculation.
Response: The calculations have been revised to reflect the maximum head more accurately.
RE�EI 7 ED
MAR 0 1 2005
DWQ
PROD #

"'R�CEIVED
®F� FBB 2 ✓i 2005
NC®ENR
- -- North Carolina Department of Environment -and -Natural -Resources
Division of Land Resources
James D. Simons, PG, PE Land Quality Section Michael F Easley, Governor
Director and State Geologist William G. Ross Jr., Secretary
February 25, 2005
LETTER OF RECEIPT OF EROSION CONTROL PLAN
UNC-W
Dr. Ronald Core, Vice Chancellor, Business Affairs
601 S. College Road
Wilmington, NC 28403
RE: Project Name: UNC-W Privatized Housing
Project ID Newha-2005-252 — EXPRESS OPTION
County: New Hanover
River Basin: Cape Fear
Submitted By: Stewart Engineering
Date Received by LOS: February 25, 2005
Plan Type: NEW
Dear Dr. Ronald Core:
This office has received a soil erosion and sediment control plan for the project listed above which
was submitted as required by the North Carolina Sedimentation Pollution Control Act (G.S. 113A-57 (4)).
The Act requires that all persons disturbing an area of one or more acres of land must obtain approval
of a soil erosion control plan prior to the commencement of the land -disturbing activity (G.S. 113A-54(d) (4)).
The Act further states that this plan must be filed a minimum of 30 days prior to the activity and the approving
authority must approve or disapprove the submitted plan within 30 days of receipt. Failure of the approving
authority to approve or disapprove the submitted plan within the 30-day period will be deemed approval of the
plan.
Commencement or continuation of a land -disturbing activity under the jurisdiction of this Act prior to
the approval of an erosion and sediment control plan is a violation of the Act.
The approval of an erosion and sediment control plan is conditioned on the applicant's compliance
with Federal and State water quality laws, regulations and rules.
If you have questions please do not hesitate to contact this office. Your cooperation in this matter is
appreciated and we look forward to working with you on this project.
Sincerely,
Carol N. Miller
Assistant Regional Engineer
cc: Steve Thomas, PE, Stewart Engineering
LQS-WiRO; SWS-WiRO
Wilmington Regional Office
127 Cardinal Drive Ext., Wilmington, North Carolina 28405-3845 • Phone: [phone] FAX: [phone]

2 -
ENGINEERING'LETTER OF TRANSMITTAL
TO: NCDENR-Wilmington Regional Office DATE: February25, 2005 JOB #: C4021
127 Cardinal Drive Extension ATTN: Linda Lewis
Wilmington, NC 28405-3845
RE: UNCW Privatized Housing — Express Review
VIA: Hand Delivery
WE ARE SENDING YOU:
SHOP DRAWINGS PRINTS X PLANS SAMPLES X OTHER
SPECIFICATIONS X COPY OF LETTER CHANGE ORDER DISKETTES
COPIES DATE DESCRIPTION
2
2/25/05
Completed Application for Stormwater Permit (Original and co
2
2125/05
Civil Plans
1
2125/05
Stormwater & Erosion Control Calculations
1
2125105
Drainage Ma
A-
n�ne�
1
2J23105
Check for $4,000.00
THESE ARE TRANSMITTED AS INDICATED BELOW:
X For Approval
For Your Use
As Requested
For Review & Comment
REMARKS:
Ms. Miller,
Approved as submitted
Approved as noted
Returned for corrections
Returned after loan to us
Resubmit copies for approval
Attached is our application for modification of the existing stormwater permit related to the above project
(SW8 970128). Thank you and please feel free to call if you have any questions.
Steve Thomas, PE
RECEIVED
JUJ
FEB 2 5 2005
DWQ
PROD #
COPY TO: Peter Aranyi, AIA — Clark Nexsen SIGNED:
Ed Shuford — UNCW Facilities
, PE — Project Manager
260 Town Hall Dr., Suite C, Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com

r
STEWART ENGINEERING INC
Steve Thomas, PE
Civil Protect Manager
260 Town Hall Drive, Suite C I Mornsvdle, NC 27560
Tel [phone] Ext 138 1 Fax [phone]
Cell 919 634 0056
sthomas®stewart-eng corn

SEDIMENT & EROSION CONTROL NARRATIVE
UNC Wilmington —Privatized Housing
Wilmington, North Carolina
EXECUTIVE SUNIN( RY
This Sediment & Erosion Control Narrative contains a review of the methods designed on the above
project to minimized sediment runoff from the construction site and also minimize erosion of the site.
Site Information
The project site is located in the rear of the campus of University of North Carolina at
Wilmington. The site may be accessed by entering the most northern entrance of campus via Randall
Drive from College Avenue. Follow Randall Drive to the rear of campus where the road ends. Turn right
onto Reynolds Drive. Turn left at the next road, Cahill Drive. Follow Cahill to the end of the road and
the project site is directly in front of what is currently a dead end.
At this time, the area has not been previously developed, and consists a mix of open area and
wooded area. The site is relatively flat, having an overall slope to the east / southeast averaging 1.5%.
In its observed condition, the majority of the stormwater runoff from the site tends to sheet flow
from west to east. A clear destination for the majority of the storm drainage is not readily discernable.
Proposed Improvements
The project proposes to construct six apartment buildings having an approximate footprint of
11,000 square feet. There will be parking surrounding the apartment buildings. A community building
will be constructed as well. The project will disturb approximately 16.49 acres.
Proposed erosion control measures include the use of a proposed dry detention pond as a
temporary sediment basin (sediment basin #1), as well as utilizing an existing stormwater detention pond
as a temporary sediment basin (sediment basin #2). The runoff from the site will sheet flow from the site
either directly into one of the two basins, or it will be directed to the sediment basin #2 with a temporary
diversion ditch.
Design Requirements
Erosion and Sedimentation control measures shall be designed in accordance with 15A NCAC,
chapter 4 (NC Sedimentation Pollution Control Act of 1973).
Stormwater management measures shall be designed in accordance with stormwater management
regulations, as detailed in 15 NCAC 0213.0216 (Section #3.b.i.B) In accordance with the requirements,
the first 1 inch of rainfall shall be collected and infiltrated. The excess volume shall bypass across a
reinforced spillway.
Permits Required
A general Erosion & Sediment Control permit will be issued by NCDENR, Division of Land
Quality through an express review process.

Construction and Erosion Control Phasing
Prior to commencement of work, the limits of disturbance will be flagged. An on -site pre -
construction conference will then be scheduled with the architect, contractor, engineer, and a NCDENR
representative to discuss requirements and procedures. Construction entrances, construction fence,
perimeter silt fence, silt fence outlets, tree protection, and other temporary erosion control devices will be
installed before inspection. `fire contractor will confirm that all applicable tree protection fencing and silt
fencing is in place as specified on the construction drawings, before any clearing is initiated.
By the time of the NCDENR site inspection, the contractor will provide a written summary of the
implementation of the proposed erosion control elements. The summary will include milestones of
device implementation and will have been reviewed by the engineer. After NCDENR site inspection
approval, land -disturbing activities will commence.
Prior to commencement of mass grading, all sediment basins and traps which are specified on the
construction drawings shall be constructed. Likewise, all required diversion ditches called for on the
plans shall be installed to carry sediment to the intended basin or trap for treatment. Complete
construction of the improvements to the existing stormwater pond are not required to be completed before
the pond is used as temporary sediment basin #2, as this pond has significantly more than the minimum
characteristics required by sediment basins in its current state.
Other Considerations
Sediment basins will be located and sized as indicated on the erosion control plans. A measuring
device must be installed in all basins to represent the amount of sediment accumulated and indicate when
basin maintenance will be required.
Sediment basins will utilize diversion ditches to capture overland and concentrated runoff flows.
If the ditches become damaged, it is the contractor's responsibility to restore it by the end of each
workday to ensure proper functionality. Temporary culvert pipes will be installed under any construction
roads to allow water flow to continue to intended basins.
Throughout the project, maintenance of all erosion control devices will be the responsibility of
the contractor. The contractor will perform daily inspections of the performance of the erosion control
devices. Any damaged or malfunctioning devices will be repaired immediately. The contractor will
report any performance discrepancies to the Engineer for possible modification.
Stormwater discharge outfalls (SDOs) will be inspected by the contractor in accordance with NC
General Statues and DENR requirements. Inspections will be performed by the contractor after each
storm event of one-half an inch or greater, with one weekly inspection minimum. DENR standard
inspection reports will be prepared, signed and copies provided to the owner, architect, and engineer, by
the contractor.
Total area denuded at any time on the project site will be limited to reduce potential for erosion.
Any areas left idle for 14 days will be temporarily stabilized by seeding. Any soil stockpiles will be
stabilized at the end of each day. As portions of the project are completed, surfaces will be permanently
stabilized.
Upon completion of the remaining site work, grades will be restored and surfaces landscaped and
permanently stabilized. Basins 3 & 6 on erosion control drawings will be excavated to their finished
grade and will remain in service as a dry detention pond (sediment basin #1) and as a stormwater

detention pond (sediment basin 42). An inspection will be scheduled with NCDENR. Upon approval, the
remaining perimeter temporary erosion control devices and inlet protection will be removed.

Riser Sediment Basin Design Worksheet
Reference NC Erosion and Sediment Control Manual
Job Name:
UNCW Privatized Housing
Job Number:
C4021
Date:
2/24/2005
Designer:
Steve Thomas, PE
Description:
Riser Sediment Basin PSD-1
Calculate peak inflow from 2, 10 & 25-year storms
(1) Use Kirpich Equation to calculate Time of Concentration (See Bureau of Reclamation, 1974)
Tc = (K/128)'(L3/H)03a5
K Value
Overland flow on grassed surfaces:
2.0
Overland flow on paved surfaces:
0.4
Channel flow in natural channels-
1.0
Channel flow in mixed urban setting:
1.1
Channel flow in paved pipes or channels.
0.2
K 1.1
L. 1271 ft.
H: 995 ft.
Tc: 13.66 minutes
Tc: 13.66 minutes
(2) Compute Intensity
Note. Values listed below are for the Raleigh -Durham IDF curves
Return Period
9
h
Intensity(in/hr)
2
171
24
4.54
10
252
30
5.77
25
300
32
6.57
(3) Calculate Rational C
(4) Compute flows
Description of Surface
C Value
Area (acres)
Grassy Areas:
0.35
0.39
Wooded Areas:
0.2
0.30
Disturbed Areas:
0.5
4.71
Impervious Areas:
0.95
0
Total
5.4 acres
Combined Rational C: 0.47
Return Period
Flow (cfs)
2
11.59
10
1473
25
1677
1 OF
2/24/2005

Calculate the required sediment storage for the pond
Disturbed Area = 4.71 acres
Using 1800 CF/AC'YR (NC Erosion and Sediment Control Manual)
Required Sediment Storage = 8478 CF
Calculate the stage -storage function for the pond
Contour
feet
Stage
feet
Rectangular Basin
Dimensions
Contour
Area
SF
Average
Contour
Area
SF
Incremental
Contour
Volume
CF
Accumulated
Contour
Volume
CF
Estimated
Stage
feet
Length ft
Width ft
0
23.5
0.0
0
24.0
0.5
3069
1535
767
767
0.50
25.0
1.5
9257
6163
6163
6930
152
26.0
2.5
14573
11915
11915
18845
2.52
27.0
3 5
18081
16327
16327
35172
3.46
Ke = 3047.3
b = 1.9722
Enter Ks and b values from the graph of storage vs. stage shown on the next page
Ks = Constant of power equation
b = Exponent of power equation
2 OF 5 2/24/2005

Design pond maximum sediment storage and design cleanout level
Sediment cleanout level is 1/2 of the design volume of the basin, referenced
to the top of the riser.
Design sediment volume = 8478 CF
Top of riser set at stage = 1.68 feet 1.6B
and EL= 25 30 feet
Check Required Surface Area = 0 01'Qi (At Top of Riser)
Area at Top of Riser = 9952 SF
Area Required = 0.116 acres = 5047 SF
Area OK? OK
Therefore, sediment cleanout mark set at volume = 4239 CF
and stage = 1.18 feet
EL= 24.68 feet
Check length to effective width ratio
Check effective flow length vs effective flow width at principal spillway elevation.
Length to width ratio = (Length) /( Effective width), should be greater than two (2).
Effective Width (We) = A L A= Surface area at principal spillway crest
A= 9952 SF
L = Length of flow path from inflow to outflow
L= 557 feet (Must be Interpolated)
Effective Width = 20.00 feet
Length to Width ratio = 27.85
Length to width OK ? YES
Determine sizes required of orincioal soillwa
Basin outflow during storms will be controlled by the barrel, which must flow
0.2 cfs/acre draining to the basin, at the elevation of emergency spillway.
Drainage area to basin (total) = 5.4 acres (referenced from above)
Principal Spillway outflow must be at least = 1.08 CFS
In order to continue with analysis, the elevation of the emergency spillway
as well as the ten year design stone to the basin (Q,a) must be determined
and entered. Length of the emergency spillway will be determined later.
It is customary to set the emergency spillway of a riser basin such as this
between one and two feet above the crest of the principal spillway.
Principal Spillway Elevation = 25.30 feet (referenced from above)
Emergency Spillway Elevation = 26.25 feel
Ten year storm, to basin (Q,o) = 14.73 cis
3 OF 5 2/24/2005

Constant TW elevation =
26.00 feet
Riser Diameter=
54 inches
Barrel Diameter=
12 inches
Riser Crest Elevation =
2530 feet
Barrel Invert In Elevation =
2400 feet
Barrel Manning's n =
0 130
Barrel Length =
94 feet
Basin
Riser as
Riser as
Barrel TW
Barrel HW
Basin
WSEL
Orifice
Weir
Conditions
Conditions
Outflow
feet)
(cfs)
Icfs
cfs
ifs
cfs
Action?
26.25
74.64
4320
0.18
500
0.18
OK
Determine sizes for emergency spillway
Required flow = Q,o - oe
Required flow= 14.55 cis
Set lop of berm elevation = 27.80 feet
In order to allow for one (1) foot of freeboard between emergency spillway water
level and top of berm, weir length required equals (from weir equation):
Depth = 0.55 feet
Length = 6 00 feet
Check freeboard between emergency spillway water level and top of berm in the twenty
five year storm (Ozz). Freeboard must be greater than or equal to one-half (0.5) foot.
025: 16.77 cfs
Required Flow: 16.58 cfs
Peak Elevation: 27.20 ft.
Freeboard: 0.60 it. OK
Design riser dewatering holes
Dewatering hole design per NC Sediment and Erosion Control Manual.
Formula used in this calculation given on page 8.07.8 of manual.
Required detention time in basin = 24 hours
Orifice discharge coefficient = 0.60 (for this computation only)
Total hole area required = 0.062 ft2
8.93 in'
if riser witt
Number= 20
Size = 0.75 inch (diameter)
Hole Area provided with above perforations = 8.84 in'
Estimated actual drawdown time = 24 26 hours
?r section with NCDOT #57 washed stone filter.
4 OF 5 2/24/2005

Summary of important elevations
Notes :
1) Anti -Flotation block must be sized outside this worksheet.
2) Design trash rack, or anti -vortex device / trash rack outside this
worksheet.
3) Design velocity dissipator for barrel for design flow through
principal spillway.
4) Fence and warning signs to be erected whenever necessary.
5) Constructed height of berm should be 10% greater than design
height to allow for settlement of bens Design height is minimum.
6) Basin sideslopes should not be steeper than 2.5:1
5 OF 5 2/24/2005

Riser Sediment Basin Design Worksheet
Reference* NC Erosion and Sediment Control Manual
Job Name:
UNCW Privatized Housing
Job Number:
C4021
Date:
2/24/2005
Designer:
Steve Thomas, PE
Description:
Riser Sediment Basin #SD-2
Calculate peak inflow from 2, 10, & 25-year storms
(1) Use Kirpich Equation to calculate Time of Concentration (See Bureau of Reclamation, 1974)
To= (K/128)'(L3/H)03e5
K Value
Overland flow on grassed surfaces:
2.0
Overland flow on paved surfaces
0.4
Channel flow in natural channels:
1.0
Channel flow in mixed urban setting:
1.1
Channel flow in paved pipes or channels:
0.2
K: 0.75
L: 1700
H: 18
To: 10.37 minutes
Tc: 10.37 minutes
(2) Compute Intensity
Note: Values listed below are for the Raleigh -Durham OF curves
Return Period
9
In
Intensity (in/hr)
2
171
24
4.98
10
252
30
6.24
25
300
32
7.08
(3) Calculate Rational C
(4) Compute flows
Description of Surface
C Value
Area (acres)
Grassy Areas:
0.35
8.18
Wooded Areas:
0.2
1.40
Disturbed Areas'
0.5
8.95
Impervious Areas:
0.95
3.54
Total
22.1 acres
Combined Rational C: 0.50
Return Period Flow (cfs)
2 54.63
10 68.55
25 7775
1 OF 5 2/24/2005

Calculate the required sediment storage for the pond
Disturbed Area = 8.95 acres
Using 1800 CF/AC'YR (NC Erosion and Sediment Control Manual)
Required Sediment Storage = 16110 CIF
Calculate the stage -storage function for the pond
Contour
feet
Stage
feet
Rectangular Basin
Dimensions
Contour
Area
SF
Average
Contour
Area
SF
Incremental
Contour
Volume
CF
Accumulated
Contour
Volume
CF
Estimated
Stage
feet
Len th Ift)
Width(it)
20.0
0.0
29839
21.0
10
33164
31502
31502
31502
1.01
22.0
2.0
36645
34905
34905
66406
1.97
23.0
3 0
40283
38464
38464
104870
2.98
24.0
4.0
44076
42180
42180
147050
4.04
250
5.0
48026
46051
46051
193101
517
26.0
6.0
52127
50077
50077
243177
6.37
27.0
7.0
Ks= 31236
b= 1.1086
Enter Ks and b values from the graph of storage vs. stage shown on the next page
Ks = Constant of power equation
b = Exponent of power equation
Storage vs. Stage
160000
14000p
y = 31236x1 1066
120000
R2 = 0.9996
100000
Beebe
60000
40000
20000
0
0.0 05 1.0 15 20 25 30 35 40 45
2 OF 5 2/24/2005

Design pond maximum sediment storage and design cleanout level
Sediment cleanout level is 1/2 of the design volume of the basin, referenced
to the top of the riser.
Design sediment volume = 16110 CF
Top of riser set at stage = 0 55 feet 0.55
and EL = 27 00 feet r
Check Required Surface Area = 0.0f *02 (At Tap of Riser)
Area at Top of Poser = 32453 SF
Area Required = 0 546 acres = 23799 SF
Area OK? OK
Therefore, sediment cleanout mark set at volume = 8055 CF
and stage = 0 29 feet
EL= 2029 feet
Check length to effective width ratio
Check effective flow length vs. effective flow width at principal spillway elevation
Length to width ratio = (Length) /( Effective width), should be greater than two (2).
Effective Width (We) = A / L A = Surface area at principal spillway crest
A = 32453 SF
L = Length of flow path from inflow to outflow
L = 442 feet (Must be Interpolated)
Effective Width = 100 00 feet
Length to Width ratio = 4.42
Length to width OK ? YES
Determine sizes reauired of orincioal soiliwa
Basin outflow during storms will be controlled by the barrel, which must flow
0.2 cfs/acre draining to the basin, at the elevation of emergency spillway.
Drainage area to basin (total) = 22 1 acres (referenced from above)
Principal Spillway outflow must be at least = 4.41 CFS
In order to continue with analysis, the elevation of the emergency spillway
as well as the ten year design storm to the basin (010) must be determined
and entered. Length of the emergency spillway will be determined later.
It is customary to set the emergency spillway of a riser basin such as this
between one and two feet above the crest of the principal spillway.
Principal Spillway Elevation = 27.00 feet (referenced from above;
Emergency Spillway Elevation = 28.00 feet
Ten year storm, to basin (oio) = 66.55 cis
3 OF 5 2/24/2005

Constant TW elevation=
2600 feet
Riser Diameter=
54 inches
Barrel Diameter =
15 inches
Riser Crest Elevation =
27.00 feet
Barrel Invert In Elevation =
26.00 feet
Barrel Mammng's n =
0.130
Barrel Length =
60 feet
Basin
Riser as
Riser as
Barrel TW
Barrel HW
Basin
WSEL
Orifice
Weir
Conditions
Conditions
Outflow
feet
cfs
cfs
cfs)
cfs
cfs
Action ?
28.00
76.58
46.65
1.17
6.92
1.17
OK
Determine sizes for emergency spillway
Required flow = Quo - Op
Required flow = 67.38 cfs
Set top of berm elevation = 29.40 feet
In order to allow for one (1) foot of freeboard between emergency spillway water
level and top of berm, weir length required equals (from weir equation):
Depth = 0.40 feet
Length = 30.00 feet
Check freeboard between emergency spillway water level and top of berm in the twenty
five year storm (Qzs). Freeboard must be greater than or equal to one-half (0.5) foot.
Q25: 77.75 cfs
Required Flow: 76.59 cfs
Peak Elevation: 2B.90 ft.
Freeboard: 0.50 ft. OK
Design riser dewatering holes
Dewatering hole design per NC Sediment and Erosion Control Manual.
Formula used in this calculation given on page 8.07.8 of manual.
Required detention time in basin = 24 hours
Orifice discharge coefficient = 0.60 (for this computation only)
Total hole area required = 0.116 ft2
16 67 in2
To provide drawdown, perforate lower half of riser with
Number= 20
Size= 1 inch (diameter)
Hole Area provided with above perforations = 15.71 in'
Estimated actual drawdown time = 25.47 hours
Cover perforated riser section with NCDOT #57 washed stone filter.
4 OF 5 2/24/2005

Summary of important elevations
Notes :
1) Anti -Flotation block must be sized outside this worksheet.
2) Design trash rack, or anti -vortex device / trash rack outside this
worksheet.
3) Design velocity dissipator for barrel for design flow through
principal spillway
4) Fence and warning signs to be erected whenever necessary.
5) Constructed height of berm should be 10 % greater than design
height to allow for settlement of berm Design height is minimum.
6) Basin sideslopes should not be steeper than 2 5:1.
5 OF 5 2/24/2005

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SW8 970128 Mod. (Privatized Housing @UNCW)
Subject: SW8 970128 Mod. (Privatized Housing @UNCW)
From: Linda Lewis <[e-mail]>
Date: Mon, 21 Feb 2005 10:00:32 -0500
To: David Boyette <[e-mail]>
CC: Steve Thomas <[e-mail]>
David:
I forgot to give you a copy of the revised application form that
came in as part of the 2002 plan revision for SW8 970128. The
current distribution of built -upon area is as follows:
Buildings 26,100 sq. ft.
Streets 8,100 sq. ft.
Parking 28,277 sq. ft.
Sidewalk 17,900 sq. ft.
Offsite 22,498 sq. ft. (From SW8 020404 new residence hall)
Regardless, the total built -upon area remains the same at 102,875
sq. ft, and the permitted drainage area was 9.5 acres.
I also did a little more research into the pond. I had originally
thought that a pond existed prior to the development of the Honors
and International housing project, but it now appears that no pond
existed. They needed fill material, so they just dug the pond 2-3
times larger than necessary to meet State requriements. You may be
able to add the new Privatized Housing without adding any more
surface area or volume to the pond, since it's already so oversized.
Also, I checked on the newer parking lots behind the Honors
building. They were part of the new residence hall permitted under
SW8 020404 and are treated by infiltration areas. The rest of the
new residence hall under 020404 is the 22,498 Offsite area permitted
under 970128.
Linda
I of 1 2/21/2005 10:00 AM

STRUCTURAL
TRANSPORTATION
CIVIL
STEWART
ENGINEERING
Meeting Minutes
University of North Carolina at Wilmington
Privatized Student Apartments
Clark Nexsen Project #: NC409.4
SEI Project #: C4021
Meeting: State Permits through NC Department of Environment and Natural Resources
A meeting for the referenced project was held at 10:00am on Tuesday November 23, 2004 in the offices
of the North Carolina Department of Environment and Natural Resources (NCDENR) located at 127
Cardinal Drive Extension in Wilmington. The purpose of the meeting was to introduce the NCDENR
reviewers to the project and to inquire what permits would be required. Representatives attending the
meeting included:
Steve Thomas, PE Stewart Engineering 919-380-8750 [e-mail]
Cameron Weaver NCDENR 910-395-3900 cameron.weaver@ncmaiLcom
Rhonda Hall NCDENR —DWQ 910-395-3900 rhonda.hall@ncmaiLcom
• Steve introduces the project to Rhonda and Cameron.
• Rhonda asks if the wetlands shown on the property have been certified by the Army Corps of
Engineers. — It has since been verified that the wetlands shown have been certified.
• Rhonda indicates that a campus Master Plan needs to be provided to determine future needs for
stormwater treatment. She indicates that she will check with Rick Shriver or Linda Lewis on this
issue and let Steve know its status.
• It is determined that New Hanover County will do Sediment & Erosion Control review and
permitting.
• Discussion of the timing of review for stormwater:
o With a regular review: 60-75 review minimum $420
o With an express review 3 weeks $4000
• Classification of blue -line stream must be determined. If this stream is classified as an SA water,
the existing detention pond may not be allowed to expand. This would force the use of only
underground detention, infiltration basins, or bio-retention basins. Rhonda indicated that she
could find out the stream classification and then let Steve know.
• The "Responsible Party" for the project should be the one to apply for the permits. If it has not
already been done, this classification needs to be made.
• Cameron and Rhonda agree that there will likely be the need for two stormwater permits for this
project; one new off -site permit and one modification of existing pond permit.
• Cameron indicates that a State non -discharge permit will likely be required. Dean Huntley will be
the contact for this permit.
• Submitted set of plans should have an overall sheet which shows the entire property boundary.
• A geotechnical report will need to be consulted to determine the infiltration coefficient of the soil.
260 Town Hall Drive, SurteG Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-cng corn

STIFWART ENGINEERING INC
Steve Thomas. PE
Civil Project Engineer
260 Town Hall Dc, S,n, C 1 Mornsville, NC 27560
Tel 919,380.8750 Ext 138 1 Fax [phone]
sthomas®stewart-eng com

The outline above is the writer's understanding of the major topics and conclusions of the meeting. If this
does not correspond with the understanding of anyone in attendance, please notify the writer.
Submitted by:
Stewart Engineering, Inc.
Steve, Thovna�-
Steve Thomas, PE
CC: All attendees (via e-mail)
Neil Sauer (via e-mail)
Peter J. Aranyi (via e-mail)
260 Town Hall Drive, Suite C Morrisville, NC 27560 Tel [phone] Fax [phone] www.stewart-eng.com