SW8971225_HISTORICAL FILE_20061023 (2)

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW8 C1-1122 5
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
® HISTORICAL FILE
❑ COMPLIANCE EVALUATION INSPECTION
DOC DATE
2 O ou 1 o 23
YYYYMMDD

wArt 9
P
�Ik
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department or Environment and Natural Resources
Alan W. Klimek, P.E. Director
Division of Water Quality
October 23, 2006
Walter Pancoe, President
The Caper Corporation, General Partner 1900 LTD. Partnership
1901 Kent Street, Suite E
Wilmington, NC 28403
Subject: Stormwater Permit No. SW8 971225MOD
Wrightsville Office Park
High Density Project
New Hanover, County
Dear Mr. Pancoe:
The Wilmington Regional Office received a complete Stormwater Management Permit
Application for Wrightsville Office Park on October 19, 2006. 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
971225MOD dated October 23, 2006, for the construction of the subject protect.
This permit shall be effective from the date of issuance until October 23, 2016, 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 1506 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 Chris Baker, or me at [phone].
Sincerely!
Edward Beck
Regional Supervisor
Surface Water Protection Section
ENB/csb: S:\WQS\STORMWAT\PERMIT\971225MOD.oct06
cc: Norris, Kuske & Tunstall
New Hanover County Building Inspections
City of Wilmington Stormwater Services
New Hanover County Engineering
Chris Baker
Wilmington Regional Office n�0.�t,Ca ohme
Central Files vaturn//y
North Carolina Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 Phone [phone] Customer Service
Internet: www.newatermrJilv.ore Location: 512 N. Salisbury St. Raleigh, NC 27604 Fax [phone]
An Equal Opportunity/Affirmative Action Employer - 50% Recycled110% Post Consumer Paper

State Stormwater Management Systems
Permit No. SW8 971225MOD
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
Walter Pancoe, President
The Caper Corporation, General Partner 1900 LTD. Partnership
Wrightsville Office Park
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 "stormwater rules')
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 October 23, 2016, and
shall be subject to the following specified conditions and limitations:
I. 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 1.6 on page 3 of this permit. The stormwater
control has been designed to handle the runoff from 92,173.6 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 in either
dedicated common areas or recorded easements. The final plats for the project
will be recorded showing all such required easements, in accordance with the
approved plans.
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.
Page 2 of 7

State Stormwater Management Systems
Permit No. SW8 971225MOD
6. The following design criteria have been provided in the wet detention pond and
must be maintained at design condition:
a. Drainage Area, acres:
Onsite, ft :
Offsite, ftz:
b. Total Impervious Surfaces, ftz:
C. Design Storm, inches:
d. Pond Depth, feet:
e. TSS removal efficiency:
f. Permanent Pool Elevation, FMSL:
g. Permanent Pool Surface Area, ftz:
h. Permitted Storage Volume, ft3:
i. Temporary Storage Elevation, FMSL
j. Controlling Orifice:
k. Permitted Forebay Volume, ft3:
I. Receiving Stream/River Basin:
M. Stream Index Number:
n. Classification of Water Body:
II. SCHEDULE OF COMPLIANCE
3.94
83,526.3
8,647.3
92,173.6
1
7.5
90%
21
5,600
17,744
22.5
1"0 pipe
3,899
Mineral Springs Branch / Cape Fear
18-74-63-2-1
"C Sw"
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. Mowin.9 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 971225MOD
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 1/2 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 971225MOD
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.
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�th 23rd day of October, 2006.
NOR 'CAROLINA ENVIRONMENTAL MANAGEMENT COMMISSION
M
Z,.1�_
forAan ime .E., erector
Division of Water Quality
By Authority of the Environmental Management Commission
Page 5 of 7

State Stormwater Management Systems
Permit No. SW8 971225MOD
Wrightsville Office Park
Stormwater Permit No. SW8 971225MOD
New Hanover Countv
Designer's Certification
I, , as a duly registered
in the State of North Carolina, having been authorized to
full time) the construction of the project,
(Project)
observe (periodically/ weekly/
for (Project Owner) hereby state that, to the
best of my abilities, due care and diligence was used in the observation of the project
construction such that the construction was observed to be built within substantial
compliance and intent of the approved plans and specifications.
The checklist of items on page 2 of this form is included in the Certification.
Noted deviations from approved plans and specification:
Signature
Registration Number
ME
SEAL
Page 6 of 7

State Stormwater Management Systems
Permit No. SW8 971225MOD
Certification Requirements:
1. The drainage area to the system contains approximately the permitted
acreage.
2. The drainage area to the system contains no more than the permitted
amount of built -upon area.
3. All the built -upon area associated with the project is graded such that the
runoff drains to the system.
4. All roof drains are located such that the runoff is directed into the system.
5. The outlet/bypass structure elevations are per the approved plan.
6. The outlet structure is located per the approved plans.
7. Trash rack is provided on the outlet/bypass structure.
8. All slopes are grassed with permanent vegetation.
9. Vegetated slopes are no steeper than 3:1.
10. The inlets are located per the approved plans and do not cause short-
circuiting of the system.
11. The permitted amounts of surface area and/or volume have been
provided.
12. Required drawdown devices are correctly sized per the approved plans.
13. All required design depths are provided.
14. All required parts of the system are provided, such as a vegetated shelf,
and a forebay.
15. The required system dimensions are provided per the approved plans.
cc: NCDENR-DWQ Regional Office
New Hanover County Building Inspections
Page 7 of 7

N KT #06073
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
1. GENERAL INFORMATION
1. Applicants name (specify the name of the corporation, individual, etc. who owns the project):
The Caper Corporation, General Partner 1900 LTD. Partnership
2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance):
Walter Pancoe. President
3. Mailing Address for person listed in item 2 above:
1901 Kent Street, Suite E
City: Wilmington State: NC Zip: 28403
Telephone Number: [phone]
4. Project Name (subdivision, facility, or establishment name — should be consistent with project name on
plans, specifications, letters, operation and maintenance agreements, etc.):
Wrightsville Office Park
5. Location of Project (street address):
2210
City:
Avenue
6. Directions to project (from nearest major intersection):
Corner of Wrightsville Avenue and Dawson Street
County:
7. Latitude: 340 13' 30" Longitude: 770 55' of project
8. Contact person who can answer questions about the project:
Name: Joseph K. Bland, E.I. Telephone Number: [phone]
11. PERMIT INFORMATION
1. Specify whether project is (check one): New Renewal X Modification
Form SWU-101 Version 3.99 Page 1 of 4

2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the
Existing permit number SW8 971225 Mod And its issue date (if known) 01-31-00
3. Specify the type of project (check one):
Low Density X High Density Redevelop
4. Additional Project Requirements (check applicable blanks):
General Permit Other
_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.
111. 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.
Modification of pond level and orifice locations to accommodate additional impervious surface;
wet detention pond.
2. Stormwater runoff from this project drains to the Cape Fear River Basin.
3. Total Project Area: 3.49 4. Project Built Upon Area: 60.6 %
5. How many drainage areas does the project have? 1
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
Mineral Springs Branch
Receiving Stream Class
C-SW
Drainage Area
3.94 AC
Existing Impervious * Area
0.38 AC
Proposed Impervious* Area
1.736 AC
% Impervious* Area total
60.63%
Impervious* Surface Area
Drainage Area I
Drainage Area 2
On -site Buildings
21,186.4 sf
On -site Streets Proposed & Existing
55,464.6 sf
On -site Parkin
On -site Sidewalks
6,875.3 sf
Other on -site
Off -site As halt & Walks
8,647.3 sf
'total: 92,173.6 sf = 2.116 AC
I Total:
* 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? As -built surveys along with computer
data compiled from CADD systems.
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.
The following covenants are intended to ensure ongoing compliance with .state stormwater 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 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 runofffrom 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
Form SWU-103
Form SWU-104
Form SWU-105
Form SWU-106
Form SWU-107
Form SWU-108
Form SWU-109
Wet Detention Basin Supplement
Infiltration Basin Supplement
Low Density Supplement
Curb Outlet System Supplement
Off -Site System Supplement
Underground Infiltration Trench Supplement
Neuse River Basin Supplement
Innovative Best Management Practice Supplement
Form SWU-101 Version 3.99 Page 3 of 4

V,I. 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
• One copy of the applicable supplement form(s) for each BMP
• Permit application processing fee of SQQ payable to NCDENR) $ 4 , 0 0 0
• Detailed narrative description of stormwater treatment / management
• Two copies of plans and specifications, including:
- 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
- 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 AUT14ORIZATION
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): Norris, Kuske & Tunstall Consulting Engineers, Inc. /Tneanb K_ Bland F. T.
Mailing Address:
902 Market Street
City: Wilmington State: NC Zip:
Phone: [phone] Fax: [phone]
VHL APPLICANT'S CERTIFICATION
28401
1, (print or type name of person listed in General Information, item 2) Walter Pancoe
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 covenants will be recorded, and that the proposed project complies with the requirements of 15A NCAC
214.1000.
Signature:
Form SWU-101 Version 3.99 Page 4 of 4
Date: 10/16/06

NKT #06073
Pemtit No.5NM 7122 5 M o0
State of North Carolina (to be provided by DWQ)
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form may be photocopied for use as an original
DWO Stormwater Management Plan Review:
A complete stormwater management plan submittal includes an application form, a wet detention basin
supplement for each basin, design calculations, and plans and specifications showing all basin and outlet
structure details.
1. PROJECT INFORMATION
Project Name: Wrightsville Office Park
Contact Person: Joseph K. Bland, E.I. Phone Number: [phone]
For projects with multiple basins, specify which basin this worksheet applies to: N/A
elevations
Basin Bottom Elevation 14 ft.
Permanent Pool Elevation 21 ft.
Temporary Pool Elevation 22.5 ft.
areas
Permanent Pool Surface Area 5,600 sq. ft.
Drainage Area 3.94 ac.
Impervious Area 2.116 ae.
(/loor of the basin)
(elevation of the orifices)
(elevation of the discharge structure overflow)
(water surface area at the orifice elevation)
(on -site and off -site drainage to the basin)
(on -site and off -site drainage to the basin)
volumes
Permanent Pool Volume 17,744 cu. ft. (combined volume of main basin and forebay)
Temporary Pool Volume 6,832 cu. ft. (volume detained above the permanent pool)
Forebay Volume 3,899 cu. ft. (approximately 20% of total volume)
Other parameters
SA/DAt 2.4 (surface area to drainage area ratio from DWQ table)
Diameter of Orifice 1" in. (2 to 5 day temporary pool draw -clown required)
Design Rainfall 1" in.
Design TSS Removal t 90 % (minimum 85%required)
Form SWU-102 Version 3.99 Page 1 of 4

Footnotes:
1. When using the Division SA/DA tables, the correct SA/DA ratio for permanent pool sizing should be computed based upon the
actual impervious % and permanent pool depth. Linear interpolation should be employed to detemnine the correct value for non-
standard table entries.
2. In the 20 coastal counties, the requirement for a vegetative filter may be waived if the wet detention basin is designed to provide
90%TSS removal. The NCDENR BMP manual provides design tables for both 85%TSS removal and 90%TSS removal.
IL REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices Manual
(N.C. Department of Environment, Health and Natural Resources, February 1999) and Administrative Code
Section: 15 A NCAC 2H .1008.
Initial in the space provided to indicate the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. If a requirement has not been met, attach justification.
Applicants Initials
N/A
a. The permanent pool depth is between 3 and 6 feet (required minimum of 3 feet).
b. The forebay volume is approximately equal to 20% of the basin volume.
c. The temporary pool controls runoff from the design storm event.
d. The temporary pool draws down in 2 to 5 days.
e. If required, a 30-foot vegetative filter is provided at the outlet (include non -erosive flow
calculations.
f. The basin length to width ratio is greater than 3: 1.
g. The basin side slopes above the permanent pool are no steeper than 3: 1.
h. A submerged and vegetated perimeter shelf with a slope of 6:1 or less (show detail).
i. Vegetative cover above the permanent pool elevation is specified.
j. A trash rack or similar device is provided for both the overflow and orifice.
k. A recorded drainage easement is provided for each basin including access to nearest right-
of-way.
N/A 1. If the basin is used for sediment and erosion control during construction, clean out of the
basin is specified prior to use as a wet detention basin.
m. A mechanism is specified which will drain the basin for maintenance or an emergency.
III. WET DETENTION BASIN OPERATION AND MAINTENANCE AGREEMENT
The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the
vegetated filter if one is provided.
This system (check one) ❑ does ® does not incorporate a vegetated filter at the outlet.
This system (check are) ❑ does ® does not incorporate pretreatment other than a forebay.
Form SWU-102 Version 3.99 Page 2 of 4

Maintenance activities shall be performed as follows:
After every significant runoff producing rainfall event and at least monthly:
a. Inspect the wet detention basin system for sediment accumulation, erosion, trash accumulation,
vegetated cover, and general condition.
b. Check and clear the orifice of any obstructions such that drawdown of temporary pool occurs
within 2 to 5 days as designed.
Repair eroded areas immediately, re -seed as necessary to maintain good vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash as needed.
Inspect and repair the collection system (i.e. catch basins, piping, swales, riprap, etc.) quarterly to
maintain proper functioning.
4. Remove accumulated sediment from the wet detention basin system semi-annually or when depth is
reduced to 75% of the original design depth (see diagram below). Removed sediment shall be disposed of
in an appropriate manner and shall be handled in a manner that will not adversely impact water quality (i.e.
stockpiling near a wet detention basin or stream, etc.)
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.
When the permanent pool depth reads 5.25 feet in the main pond, the sediment shall be removed.
When the permanent pool depth reads
Sediment
Bottom
ral El. 1575
------------
vation 14
FOREBAY
5.25 feet in the forebay, the sediment shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 21
Sediment Removal Elevation 15_75 75%
------------------------- i -----
Bottom Elevation 14
MAIN POND
5. Remove cattails and other indigenous wetland plants when they cover 50% of the basin surface. These
plants shall be encouraged to grow along the vegetated shelf and forebay berm.
6. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through
the emergency drain shall be minimized to the maximum extent practical.
Form SW U-102 Version 3.99 Page 3 of 4

All components of the wet detention basin system shall be maintained in good working order.
I acknowledge and agree by my signature below that 1 am responsible for the performance of the seven
maintenance procedures listed above. 1 agree to notify DWQ of any problems with the system or prior to any
changes to the system or responsible party.
Print name: Walter Pancoe
Title: President
Address: 1901 Kent Street, Suite E Wilmington, NC 28403
Phone:
Signature:
Date:
Note: The legally responsible party should not be a homeowners association unless more than 50%of the lots have been sold and
a resident of the subdivision has been named the president.
l jyl It �S , �1 T-( a Notary Public for the State of _I � Q (�, I n CA
County "o"f J,� rI C,Ln u� Q do hereby certify that qe T- �)A
Personally appeared before me this _LSLLI day of S%ldil�i�, �, and acknowledge the due
Execution of the foregoing wet detention basin maintenance requirements. Witness my hand and official seal.
��TAgY
pUBOG A
Signature
My commission expires() OJ— - f
Form SWU-102 Version 3.99 Page 4 of 4

.\tlC;lrllbtlj/
V 0o;��

NORRIS, KUSKE &TUNSTALL
CONSULTING ENGINEERS, INC.
October 18, 2006
Mr. Cameron Weaver, Express Review Coordinator
NC DENR / Division of Water Quality
Water Quality Section
127 Cardinal Drive Extension
Wilmington, NC 28405-3845
Re: State Stormwater Permit Express Review Submittal
Wrightsville Office Park
Wilmington, NC
NKT Project No. 06073
Dear Mr. Weaver:
J. Phillip Norris, P.E.
John A. Kuske, III, P.E.
John S. Tunstall, P.E.
J.A. Kuske, P.E. of Counsel
Enclosed are two (2) sets of plans for the subject project, one (1) set of calculations,
one (1) copy of the stormwater narrative, the original Division of Water Quality
Stormwater Management Permit application, the original SWU-102 supplement form
and a $4,000.00 check for the express permit review fee.
The following sheets should be pulled out of the various project documents that are
contained within your files to make a complete set of all phased development as
Wrightsville Office Park.
Pull the following out of Andrew & Kuske # 99317:
Sheets: C-1; C-2; C-4 omitting the pond cross section and outlet structure
and sheet PR-1.
Pull the following from NKT# 04122:
Sheet C-1
Along with all the submitted project documents from NKT# 06073, the numerous
grading sheets reflect the changes from initial permitting through the final phase with
augmentation to the design of permitted structures. Together all three sheets compile
grading information of all installed paving.
Also, the following items have been added to the detail sheet as requested at the
preliminary meeting on October 17, 2006.
1. Detail of augmented outlet structure.
2. New pond cross section reflecting the change in normal pond elevation
and forebay modification.
902 Market Street • Wilmington, NC 28401-4733 0 Phone: [phone] • Fax: [phone]

Please review this information for approval and contact us with any questions or
comments you may have. Thank you for your assistance on this project.
Sincerely,
NORRIS, KUSKE & TUNSTALL
CONSULTING ENGINEERS, INC.
C
Joseph K. Bland, EI
JKB/kbh
06073 10-18-06-s-sw express-Itr
Enclosures

STORMWATER SYSTEM & EROSION CONTROL NARRATIVE
RECEIVED
0CT 1 9 2006
BY:SW�R�1225 op
WRIGHTSVILLE OFFICE PARK
WILMINGTON, NORTH CAROLINA
For
The Caper Corporation
Walter Pancoe
1901 Kent Street, Suite E
Wilmington, NC 28403
[phone]
September 2006
Prepared by:
NORRIS, KUSKE & TUNSTALL CONSULTING ENGINEERS, INC.
902 Market Street
Wilmington, North Carolina 28401
[phone]
[phone] (Fax)
E-mail: [e-mail]
NKT Project No. 06073

[.�:1:7t11LVI
DESCRIPTION:
The project site is a 3.49 acre tract located at the corner of Wrightsville Avenue
and Dawson Street. This application is a requested modification of Permit #SW8
971225 Modification. The existing permit for this project lists a total of 1.69 acres of
impervious surface coverage which drains to a wet detention pond. The client wishes
to proceed with Phase 4 of this project. It has been discovered that the final proposed
improvements will exceed the state stormwater permit. An additional 0.426 acres will
be required to be permitted to be within compliance. The soils that are present at the
Phase 4 location are lightly vegetated sandy clay topsoil. Grades within this area range
from 4% to 1%. The final phase will disturb approximately 0.5 acres of which 0.426
acres will be covered with impervious surface. The run-off for the entire site was
designed using the TR-55 Method for pre and post development for the 10 year storm
event and rainfall data for the area. Construction is scheduled to begin as soon as
possible.
EROSION CONTROL MEASURES:
The attached plans and specifications outline the requirements for erosion control
measures. Silt fencing will be provided around the area of the retention pond which abuts
to the Phase 4 disturbed area and around any catch basins which lie within the disturbed
area. Gravel check dams will not be provided unless the contractor has to temporarily
discharge into an open ditch instead of the proposed storm drain outfall. A gravel
construction entrance will not be needed for this project since two asphalt entrances
already exist upon the property. Any maintenance will be provided by the grading
contractor and developer.
STORMWATER MANAGEMENT MEASURES:
The project site is located in New Hanover County. Land disturbing on the site
will not exceed one acre, but it has been determined that the final impervious surface
coverage to be installed will be out of compliance with permit #SW8 971225
Modification. The proposed 0.426 acres to be constructed will be diverted to the
existing retention pond. It has been determined that the existing retention pond will
accommodate the additional stormwater run-off with a small outlet structure
modification.
First, the permanent pool elevation will be raised from 20 feet to 21 feet. Next,
the 1" orifice will be moved up to an elevation of 21 feet and the secondary orifice will
be moved up to an elevation of 22.5 feet and its dimension shall be modified to 4 foot
wide by 0.5 feet in height. The emergency outlet will remain as permitted on the initial
permit. The stormwater detention pond will accommodate approximately 2.116 acres of
impervious surface which corresponds to 60.63% impervious area lot coverage.

CONSTRUCTION SEQUENCE:
Any silt fencing will be installed prior to the beginning of any clearing and grading
operations. Additional silt fencing will be installed when and if conditions warrant during
construction. All disturbed areas will be landscaped or seeded upon completion.

EROSION CONTROL NOTES AND MAINTENANCE PLAN
1. Install erosion control measures before beginning construction or as soon
thereafter as possible. All erosion and sediment control practices will be
checked for stability and operation following every runoff -producing rainfall but in
no case less than once every week. Any needed repairs will be made
immediately to maintain all practices as designed.
2. Install erosion control measures around the drop inlets as shown on the plans to
trap silt during construction. Inspect the erosion control around the inlets after
each rain and make repairs immediately. Remove sediment when it becomes
0.50 deep to provide adequate storage volume for subsequent rains. When the
contributing drainage area has been adequately stabilized, remove all materials
and any unstable soil and either salvage or dispose of it properly. Bring the
disturbed area to proper grade and appropriately stabilize all bare areas around
the drop inlets.
3. Sediment will be removed from behind the silt fence when it becomes 0.5 feet
deep at the fence. The sediment fence will be repaired as necessary to maintain
a barrier. Silt fence stakes shall be spaced 6 feet apart unless a wire backing is
used with 8 foot stake spacing.
4. Inspect temporary sediment traps / check dams after each period of significant
rainfall. Remove sediment and restore the trap to its original dimensions when
the sediment has accumulated to one-half the design depth of the trap. Place
the sediment that is removed in the designated disposal area and replace the
contaminated part of the gravel facing. Check the structure for damage from
erosion or piping. Periodically check the depth of the spillway to ensure it is a
minimum of 1.5 ft below the low point of the embankment. Immediately fill any
settlement of the embankment to slightly above design grade. Any riprap
displaced from the spillway must be replaced immediately. After all sediment -
producing areas have been permanently stabilized, remove the structure and all
unstable sediment. Smooth the area to blend with the adjoining areas and
stabilize properly.
5. 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. In any event, slopes left exposed will, within 21 calendar days of
completion of any phase of grading, be planted or otherwise provided with
temporary or permanent ground cover, devices, or structures sufficient to restrain
erosion.
6. All disturbed areas shall be seeded within 15 days of disturbance. All seeded
areas will be fertilized, reseeded as necessary and mulched according to

specifications in the vegetative plan to maintain a vigorous, dense vegetative
cover.
7. More stringent measures shall be used to halt erosion if those shown on this plan
are not effective.
8. All erosion shall be controlled including side slopes before the project is
completed.
9. Remove temporary measures upon completion of project. All permanent
measures will be well established before project closeout.

SECTION 02920
SOIL EROSION AND SEDIMENTATION CONTROL
1. GENERAL
1.1 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.
1.2 The Contractor shall install all required silt fences, and construction entrances at
the initiation of work, and have these measures reviewed and approved by the local
permit authority prior to clearing and grading operations.
1.3 The Contractor shall, within 15 days of suspension or completion of land
disturbing activities, provide permanent protective covering for disturbed areas.
Temporary and permanent erosion control measures shall be coordinated to assure
economical, effective, and continuous erosion and siltation control throughout the
construction and post -construction period. Use the specified seed for both temporary and
permanent seeding.
2. PRODUCTS
2.1 Asphalt for anchoring mulch shall be Type SS-1 Emulsion.
2.2 Fertilizer shall be 10-10-10 grade or equivalent.
2.3 Lime shall be dolomitic agricultural ground limestone containing not less than 10
percent magnesium oxide.
2.4 Mulch shall be small grain straw, hay, wood chips, asphalt emulsion, jute or other
suitable material free of undesirable weed seed.
2.5 Phosphate shall be 20 percent superphosphate or equivalent.
2.6 Seed shall be 20% carpet grass, 24% Bermuda, 20% turf Fescue, 10% Creeping
Red Fescue, and 24% Annual Rye grain. Bermuda seed shall be hulled for warm
weather planting and unhulled for cool weather planting. Purity of seed shall be a
minimum of 98 percent and germination shall be a minimum of 85 percent.
2.7 Silt fence shall consist of NCDOT Class A fabric supported by wood or metal
posts spaced not more than 6 feet on center. The bottom of the fabric shall be buried a
minimum of 6 inches.
2.8 Gravel for check dams shall be #57 washed stone.

2.9 Aggregate for construction entrance shall be #4 washed stone.
2.10 Stone rip rap for check dams and erosion control shall be NCDOT Class A or B
as shown.
3. EXECUTION
3.1 General: Take every practicable measure during construction or suspension to
work to minimize erosion and siltation. Measures should include good construction
practices, temporary physical barriers to sediment travel, settling basins for new ditches,
and establishment of vegetative cover.
3.2 Construction Practices
3.2.1 Avoid dumping soil or sediment into any wetland or watercourse.
3.2.2 Maintain an undisturbed vegetative buffer where possible between a natural
watercourse and trenching and grading operations.
3.2.3 Avoid equipment crossings of streams, creeks, and ditches where practicable.
3.2.4 Grade all cut, fill and ditch slopes to minimum slope of 3:1, unless otherwise
shown or directed.
3.3 Temporary Physical Barriers are required where sedimentation on off site
property or excessive erosion is a problem.
3.3.1 Mulch shall be used for temporary stabilization of areas subject to excessive
erosion and for protection of seedbeds after planting where required.
1. Apply grain straw and hay at a rate of 75 to 100 pounds per 1000 square feet
and wood chips at a rate of 500 pounds per 1000 square feet. Jute and mesh
should be installed as per manufacturer's instructions.
2. Asphalt emulsion for slope stabilization should be applied at a rate of 1,000
gallons per acre. Asphalt emulsion used for anchoring straw should be
applied at a rate of 150 gallons per ton of straw.
3.3.2 Silt Fences shall be used at the base of slopes to restrict movement of sediment
from the site. Clean silt fence of accumulated sediment after each rainfall event or
when it exceeds a depth of 0.5 feet above natural grade.
3.3.3 Stone Check Dams, placed at the discharges of creeks, ditches, and swales,
shall consist of Class A or Class B erosion control stone at minimum two feet high and

three feet thick across the watercourse, with a one foot thick layer of gravel on upstream
side. Remove sediment if accumulated to a depth of 1.0 feet at upstream face.
3.4 Vegetative Cover: Establish and maintain permanent vegetative cover on all
unpaved areas disturbed by the work.
3.4.1 Preparation of Seedbed: Areas to be seeded shall be scarified to a depth of 4
inches and 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:
Lime: 45 pounds per 1000 square feet
Phosphorous: 20 pounds per 1000 square feet
Fertilizer: 17 pounds per 1000 square feet
3.4.2 Seeding: Disturbed areas shall be seeded with 2 to 3 pounds per 1000 square
feet of the specified seed mixture. Seed shall be worked into the bed to a depth of 1/4
inch. Regrade and seed eroded areas immediately
3.4.3 Mulch all areas immediately after seeding. Mulch shall be applied and anchored
as specified hereinbefore. Reapply as necessary to retain cover until grass is
established.
3.5 Construction Entrance: Provide an aggregate drive, 20 feet wide by 50 feet long
by 6 inches thick at each entrance to the site used by construction vehicles, until such
time as the permanent roadway is constructed. Remove soil if accumulated to a depth
greater than 0.5 inches.
3.6 Maintenance: The Owner and Contractor shall be responsible for maintaining all
temporary and permanent erosion control measures. Temporary structures shall be
maintained until such time as vegetation is firmly established in the area protected by
the structure. Permanent streambank protection and grassed areas shall be
maintained until completion of the project. Areas that fail to show a suitable stand of
grass or which are damaged by erosion shall be immediately repaired.
END OF SECTION

Dote Design NORRIS. KUSKE &TUNSTALL 902 Market $1. $heel
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Date' Design ANORRIS, KUSKE&TUNSTALL
11113
CONSULTING ENGINEERS, INC.
Check Job I For
902 Market St. et
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Project: Wrightsville Office Park
Drainaae Basin:
Drainage Area, DA =
Impervious Area =
Pervious Area =
% Impervious, I =
NORRIS, KUSKE TUNSTALL
CONSULTING ENGINEERS, INC.
State Stormwater Calculations
171,626 sf
92,173 sf
79,453 sf
53.71 %
Storaae Volume Required (Simple Method):
Design Depth, D =
1.0 in
Normal Pool Elevation =
21
State Storage Pool Elevation =
22.5
Bottom Pool Elevation =
14 ft
Runoff Volume. Rv =
0.533 in/in
Required Storage Volume =
Provided Storage Volume =
Required Surface Area:
% Imp SA/DA
Low 50 1.9
High 60 2.4
SA/DA =
Required Surface Area =
Provided Surface Area =
Drawdown Orifice
7,628 ft3
9,761 ft3
SA = 5,600 sf
SA = 7,415 sf
Rv = 0.05 + 0,009*1
Depth Proj % Imp
7.00 53.71
V=D/12xRvxDA
OKI
2.09 90% TSS removal, no filter strip
3,579 sf
5,600 sf OKI
Avg. Head =
0.75 ft
Drawdown Time =
2 days 172,800 s
Internal Diameter =
0.12 ft
Internal Diameter=
1.39in
Drawdown Time =
5 days 432,000 s
Internal Diameter =
0.07 ft
Internal Diameter=
0.88 in
Avg Internal Diameter =
1.14 in
Design Orifice Diameter =
1.00 in OKI
�I21
9/14/2006
NKT No: 06073
C:\Documents and Settings\Joe K\My Documents\Project Documen ts\2006\06073\DWQ Wet Pond Simple

pre devolpment wrightsville office park Type 111 24-hr wilmington 10 yr Rainfall= 7. 00"
Prepared by {enter your company name here)
HydroCADO 7,10 s/n 000479 © 2005 HVdroCAD Software Solutions LLC 9/11/2006
Subcatchment 1S: (new Subcat)
[49] Hint: Tc<2dt may require smaller dt
Runoff = 14.86 cfs @ 12.14 hrs, Volume= 1.290 af, Depth> 3.93"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.10 hrs
Type III 24-hr wilmington 10 yr Rainfall=7.00"
Area (ac) CN Description
3.940 73 Woods, Fair, HSG C
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (f /sec) (cfs)
10.0 Direct Entry, entire site

,/1
pre devolpment wrightsville office park Type 111 24-hr wilmington 10 yr Rainfall=7.00"
Prepared by {enter your company name here}
HydroCAD® 7.10 sln 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Subcatchment 1S: (new Subcat)
Hydrograph
Runoff
Time (hours)

U�I L1
pre devolpment wrightsville office park Type 111 24-hr wilmington 50 yr Rain/all=9.01 "
Prepared by {enter your company name here)
Subcatchment 1S: (new Subcat)
[49] Hint: Tc<2dt may require smaller dt
Runoff = 21.52 cfs @ 12.14 hrs, Volume= 1.874 at, Depth> 5.71"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.10 hrs
Type III 24-hr wilmington 50 yr Rainfall=9.01"
Area (ac) CN Description
3.940 73 Woods, Fair, HSG C
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 Direct Entry, entire site

pre devolpment wrightsville office park Type /// 24-hr wilmington 50 yr Rainfall=9,01"
Prepared by {enter your company name here)
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
N
U
Subcatchment 1S: (new Subcat)
Hydrograph
Time (hours)
❑ Runoff

Ui24
Wrightsville Office Park Type 111 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 @ 2005 HydroCAD Software Solutions LLC 9/11/2006
Subcatchment 1S: entire area including Cowell Ave
(49] Hint: Tc<2dt may require smaller dt
Runoff = 14.74 cfs @ 12.14 hrs, Volume= 1.280 af, Depth> 3.90"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.10 hrs
Type III 24-hr wilmington 10 year Rainfall=6.72"
Area (ac) CN Description
2.095 98 Paved parking & roofs
1.845 49 50-75% Grass cover, Fair, HSG A
3.940 75 Weighted Average
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 Direct Entry, entire site

63i�1
Wrightsville Office Park Type 111 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Subcatchment 1S: entire area including Cowell Ave
Hydrograph
Runoff
Time (hours)

Wrightsville Office Park Type IN 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
Pond 2P: retention pond
Inflow Area =
3.940 ac,
Inflow Depth > 3.90"
for wilmington 10 year event
Inflow =
14.74 cfs @
12.14 hrs, Volume=
1.280 of
Outflow =
2.78 cfs @
12.72 hrs, Volume=
0.641 af, Atten= 81 %, Lag= 34.8 min
Primary =
2.78 cfs @
12,72 hrs, Volume=
0.641 of
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.10 hrs
Peak Elev= 22.86' @ 12,72 hrs Surf.Area= 7,849 sf Storage= 30,253 cf
Flood Elev= 24.00' Surf.Area= 9,358 sf Storage= 40,057 cf
Plug -Flow detention time= 242.0 min calculated for 0.641 of (50% of inflow)
Center -of -Mass det. time= 128.4 min ( 952.7 - 824.3 )
Volume
Invert Avail.Storage Storage
Description
#1
14.00'
40,057 cf Custom Stage Data (Prismatic�isted below
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
14.00
10
0
0
20.00
4,261
12,813
12,813
21.00
5,600
4,931
17,744
21.50
6,132
2,933
20,677
22.00
6,890
3,256
23,932
22.50
7,415
3,576
27,508
23.00
8,026
3,860
31,369
23.50
8,685
4,178
35,546
24.00
9,358
4,511
40,057
Device Routina Invert Outlet Devices
#1
Primary
20.00'
24.0" x 60.0' long Culvert Ke= 0.500
Outlet Invert= 19.42' S= 0.0097 T Cc= 0.900
n= 0.012 Concrete pipe, finished
#2
Device 1
21.00'
1.0" Vert. Orifice/Grate C= 0.600
#3
Device 1
22.50'
4.00' W x 0.50' H Vert. Orifice/Grate C= 0.600
#4
Primary
23.20'
16.0' long x 0.8' high Sharp -Crested Rectangular Weir
0 End Contraction(s)
Primary OutFlow Max=2.72 cfs @ 12.72 hrs HW=22.85' (Free Discharge)
1=Culvert (Passes 2.72 cfs of 20.59 cfs potential flow)
�2=OrificelGrate (Orifice Controls 0.04 cfs @ 6.5 fps)
3=OrificelGrate (Orifice Controls 2.68 cfs @ 1.9 fps)
=Sharp -Crested Rectangular Weir( Controls 0.00 cfs)

Wrightsville Office Park Type 111 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Pond 2P: retention pond
Hydrograph
O Inflow
p Primary
Time (hours)

12174
Wrightsville Office Park
Prepared by (enter your cor
Elevation Primary
(feet)
(cfs)
14.00
0.00
14.10
0.00
14.20
0.00
14.30
0.00
14.40
0.00
14.50
0.00
14.60
0.00
14.70
0.00
14.80
0.00
14.90
0.00
15.00
0.00
15.10
0.00
15.20
0.00
15.30
0.00
15.40
0.00
15.50
0.00
15.60
0.00
15.70
0.00
15.80
0.00
15.90
0.00
16.00
0.00
16.10
0.00
16.20
0.00
16.30
0.00
16.40
0.00
16.50
0.00
16.60
0.00
16.70
0.00
16.80
0.00
16.90
0.00
17.00
0.00
17.10
0.00
17.20
0.00
17.30
0.00
17.40
0.00
17.50
0.00
17.60
0.00
17.70
0.00
17.80
0.00
17.90
0.00
18.00
0.00
16.16
0.00
18.20
0.00
18.30
0.00
18.40
0.00
18.50
0.00
18.60
0.00
18.70
0.00
18.80
0.00
18.90
0.00
19.00
0.00
19.10
0.00
Type 11124-hr wilmington 10 year Rainfall=6.72"
name
Stage -Discharge for Pond 2P: retention pond
Elevation Primary
(feet)
(cfs)
19.20
0.00
19.30
0.00
19.40
0.00
19.50
0.00
19.60
0.00
19.70
0.00
19.80
0.00
19.90
0.00
20.00
0.00
20.10
0.00
20.20
0.00
20.30
0.00
20.40
0.00
20.50
0.00
20.60
0.00
20.70
0.00
20.80
0.00
20.90
0.00
21.00
0.00
21.10
0.01
21.20
0.01
21.30
0.01
21.40
0.02
21.50
0.02
21.60
0.02
21.70
0.02
21.80
0.02
21.90
0.02
22.00
0.03
22.10
0.03
22.20
0.03
22.30
0.03
22.40
0.03
22.50
0.03
22.60
0.44
22.70
1.18
22.80
2.14
22.90
3.28
23.00
4.58
23.10
5.60
23.20
6.41
23.30
8.80
23.40
12.58
23.50
17.33
23.60
22.93
23.70
29.31
23.80
36.43
23.90
44.27
24.00
52.81

Wrightsville Office Park Type 111 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
Stage -Area -Storage for Pond 2P: retention pond
Elevation
Surface
Storage
(feet)
(sq-ft)
(cubic -feet)
14.00
10
0
14.10
81
214
14.20
152
427
14.30
223
641
14.40
293
854
14.50
364
1,068
14.60
435
1,281
14.70
506
1,495
14.80
577
1,708
14.90
648
1,922
15.00
719
2,136
15.10
789
2,349
15.20
860
2,563
15.30
931
2,776
15.40
1,002
2,990
15.50
1,073
3,203
15.60
1,144
3,417
15.70
1,214
3,630
15.80
1,285
3,844
15.90
1,356
4,057
16.00
1,427
4,271
16.10
1,498
4,485
16.20
1,569
4,698
16.30
1,640
4,912
16.40
1,710
5,125
16.50
1,781
5,339
16.60
1,852
5,552
16.70
1,923
5,766
16.80
1,994
5,979
16.90
2,065
6,193
17.00
2,136
6,407
17.10
2,206
6,620
17.20
2,277
6,834
17.30
2,348
7,047
17.40
2,419
7.261
17.50
2,490
7,474
17.60
2,561
7,688
17.70
2,631
7,901
17.80
2,702
8,115
17.90
2,773
8,328
18.00
2,844
8,542
18.10
2,915
8,756
18.20
2,986
8,969
18.30
3,057
9,183
18.40
3,127
9,396
18.50
3,198
9,610
18.60
3,269
9,823
18.70
3,340
10,037
18.80
3,411
10,250
18.90
3,482
10,464
19.00
3,553
10,678
19.10
3,623
10,891
Elevation
Surface
Storage
(feet)
(sq-ft)
(cubic -feet)
19.20
3,694
11,105
19.30
3,765
11,318
19.40
3,836
11,532
19.50
3,907
11,745
19.60
3,978
11,959
19.70
4,048
12,172
19.80
4,119
12,386
19.90
4,190
12.599
20.00
4,261
12,813
20.10
4,395
13,306
20.20
4,529
13,799
20.30
4,663
14,292
20.40
4,797
14,785
20.50
4,931
15,278
20.60
5,064
15,771
20.70
5,198
16,264
20.80
5,332
16,757
20.90
5,466
17,250
21.00
5,600
17,744
21.10
5,706
18,330
21.20
5,813
18,917
21.30
5,919
19,503
21.40
6,026
20,090
21.50
6.132
20,677
21.60
6,284
21,328
21.70
6.435
21,979
21.80
6,587
22,630
21.90
6,738
23,281
22.00
6,890
23,932
22.10
6,995
24,647
22.20
7,100
25,362
22.30
7,205
26,078
22.40
7,310
26,793
22.50
7,415
27,508
22.60
7,537
28,280
22.70
7,659
29,052
22.80
7,782
29,824
22.90
7,904
30,596
23.00
8,026
31,369
23.10
8,158
32,204
23.20
8,290
33,040
23.30
8,421
33,875
23.40
8,553
34,711
23.50
8,685
35,546
23.60
8,820
36,448
23.70
8,954
37,351
23.80
9,089
38,253
23.90
9,223
39,155
24.00
9,358
40,057

(yjz1
Wrightsville Office Park Type 111 24-hr wilmington 10 year Rainfall=6.72"
Prepared by {enter your company name here}
Estimated Pond Sizing for Pond 2P: retention pond
Time Desired -Peak Required -Storage
(hours)
(cfs)
(acre-feet)
12.30
9.64
0.104
12.50
5.37
0.379
12.70
2.70
0.556
12.90
2.08
0.609
13.10
1.70
0.648
13.30
1.52
0.671
13.50
1.42
0.687
13.70
1.32
0.704
13.90
1.22
0.722
14.10
1.12
0.741
14.30
1.05
0.756
14.50
1.00
0.768
14.70
0.96
0.780
14.90
0.91
0.793
15.10
0.86
0.807
15.30
0.81
0.821
15.50
0.76
0.836
15.70
0.71
0.851
15.90
0.66
0.867
16.10
0.61
0.884
16.30
0.57
0.894
16.50
0.55
0.903
16.70
0.53
0.912
16.90
0.51
0.921
17.10
0.49
0.930
17.30
0.46
0.939
17.50
0.44
0.949
17.70
0.42
0.959
17.90
0.40
0.970
18.10
0.37
0.980
18.30
0.36
0.986
18.50
0.36
0.990
18.70
0.35
0.994
18.90
0.34
0.998
19.10
0.34
1.002
19.30
0.33
1.006
19.50
0.32
1.010
19.70
0.32
1.015
19.90
0.31
1.019
20.10
0.30
1.024
20.30
0.30
1.028
20.50
0.29
1.031
20.70
0.29
1.035
20.90
0.28
1.039
21.10
0.28
1.043
21.30
0.27
1.047
21.50
0.27
1.051
21.70
0.26
1.055
21.90
0.26
1.059
22.10
0.25
1.063
22.30
0.25
1.068
22.50
0.24
1.072
Time Desired -Peak Required -Storage
(hours)
(cfs)
(acre-feet)
22.70
0.24
1.076
22.90
0.23
1.081
23.10
0.23
1.086
23.30
0.22
1.090
23.50
0.22
1.095
23.70
0.21
1.100
23.90
0.20
1.104

Wrightsville Office Park Type Ill 24-hr wilmington 50 year Rainfall=9.01"
Prepared by (enter your company name here)
HydroCAD® 7,10 s/n 000479 @ 2005 HydroCAD Software Solutions LLC 9/11 /2006
Subcatchment 1S: entire area including Cowell Ave
[49] Hint: Tc<2dt may require smaller dt
Runoff = 22.39 cfs @ 12.14 hrs, Volume= 1.955 af, Depth> 5.95"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.10 hrs
Type III 24-hr wilmington 50 year Rainfall=9.01"
Area (ac) CN Description
2.095 98 Paved parking & roofs
1.845 49 50-75% Grass cover, Fair, HSG A
3.940 75 Weighted Average
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 Direct Entry, entire site

Wrightsville Office Park Type 111 24-hr wilmington 50 year Rainfall=9.01 "
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Subcatchment 1S: entire area including Cowell Ave
Hydrograph
0 RunOR
Time (hours)

Wrightsville Office Park
by (enter your company name he
D 7.10 s/n 000479 © 2005 HvdroCAC
Type 111 24-hr wilmington 50 year Rainfall=9.01 "
Pond 2P: retention pond
Inflow Area =
3.940 ac,
Inflow Depth > 5.95"
for wilmington 50 year event
Inflow =
22.39 cfs @
12.14 hrs, Volume=
1.955 of
Outflow =
14.57 cfs @
12.34 hrs, Volume=
1.312 af, Atten= 35%, Lag= 11.7 min
Primary =
14.57 cfs @
12.34 hrs, Volume=
1.312 of
Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0,10 hrs
Peak Elev= 23.46' @ 12.34 hrs Surf.Area= 8,632 sf Storage= 35,212 cf
Flood Elev= 24.00' Surf.Area= 9,358 sf Storage= 40,057 cf
Plug -Flow detention time= 169.E min calculated for 1.306 of (67% of inflow)
Center -of -Mass det. time= 75.3 min ( 887.6 - 812.3 )
Volume
Invert Avail.Storage Storage
Description
#1
14.00'
40,057 cf Custom Stage Data (Prismatic)Listed below
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
14.00
10
0
0
20.00
4,261
12,813
12,813
21.00
5,600
4,931
17,744
21.50
6,132
2.933
20,677
22.00
6,890
3,256
23,932
22.50
7,415
3,576
27,508
23.00
8,026
3,860
31,369
23.50
8,685
4,178
35,546
24,00
9,358
4,511
40,057
Device Routina Invert Outlet Devices
#1
Primary
20.00'
24.0" x 60.0' long Culvert Ke= 0.500
Outlet Invert= 19.42' S= 0.0097 T Cc= 0.900
n= 0.012 Concrete pipe, finished
#2
Device 1
21.00'
1.0" Vert. Orifice/Grate C= 0.600
#3
Device 1
22.50'
4.00' W x 0.50' H Vert. Orifice/Grate C= 0.600
#4
Primary
23.20'
16.0' long x 0.8' high Sharp -Crested Rectangular Weir
0 End Contraction(s)
Primary OutFlow Max=13.38 cfs @ 12.34 hrs HW=23.42' (Free Discharge)
1=Culvert (Passes 7.87 cfs of 23.52 cfs potential flow)
L
L2=Orifice/Grate (Orifice Controls 0.04 cfs @ 7.4 fps)
3=Orifice/Grate (Orifice Controls 7.82 cfs @ 3.9 fps)
=Sharp -Crested Rectangular Weir(Weir Controls 5,51 cfs @ 1.6 fps)

(phi
Wrightsville Office Park Type /// 24-hr wilmington 50 year Rainfall=9. 0 1'
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Pond 2P: retention pond
Hydrograph
© Inflow
Primary
Time (hours)

Wrightsville Office Park
Type /// 24-hr wilmington 50 year Rainfall= 9. 01 "
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 © 2005 HydroCAD Software Solutions LLC 9/11/2006
Elevation Primary
(feet) (cfs)
14.00 0.00
14.10 0.00
14.20 0.00
14.30 0.00
14.40 0.00
14.50 0.00
14.60 0.00
14.70 0,00
14.80 0.00
14.90 0.00
15.00 0.00
15.10 0.00
15.20 0.00
15.30 0.00
15.40 0.00
15.50 0.00
15.60 0.00
15.70 0.00
15.80 0.00
15.90 0.00
16.00 0.00
16.10 0.00
16.20 0.00
16.30 0.00
16.40 0.00
16.50 0.00
16.60 0.00
16.70 0.00
16.80 0.00
16.90 0.00
17.00 0.00
17.10 0.00
17.20 0.00
17.30 0.00
17.40 0.00
17.50 0.00
1T60 0.00
17.70 0.00
17.80 0.00
17.90 0.00
18.00 0.00
18.10 0.00
18.20 0.00
18.30 0.00
18.40 0.00
18.50 0.00
18.60 0.00
18.70 0.00
18.80 0.00
18.90 0.00
19.00 0.00
19.10 0.00
Stage -Discharge for Pond 2P: retention pond
Elevation Primary
(feet)
(cfs)
19.20
0.00
19.30
0.00
19.40
0.00
19.50
0.00
19.60
0.00
19.70
0.00
19.80
0.00
19.90
0.00
20.00
0.00
20.10
0.00
20.20
0.00
20.30
0.00
20.40
0.00
20.50
0.00
20.60
0.00
20.70
0.00
20.80
0.00
20.90
0.00
21,00
0.00
21.10
0.01
21,20
0.01
21.30
0.01
21.40
0.02
21.50
0.02
21.60
0.02
21.70
0.02
21.80
0.02
21.90
0.02
22.00
0.03
22.10
0.03
22.20
0.03
22.30
0.03
22.40
0.03
22.50
0.03
22.60
0.44
22.70
1.18
22.80
2.14
22.90
3.28
23.00
4.58
23.10
5.60
23.20
6.41
23.30
8.80
23.40
12.58
23.50
17.33
23.60
22.93
23.70
29.31
23.80
36.43
23.90
44.27
24.00
52.81

Wrightsville Office Park
Prepared by {enter your company name In
Type 111 24-hr wilmington 50 year Rainfall=9.01 "
Stage -Area -Storage for Pond 2P: retention pond
Elevation
Surface
Storage
(feet)
(sq-ft)
(cubic -feet)
14.00
10
0
14.10
81
214
14.20
152
427
14.30
223
641
14.40
293
854
14.50
364
1,068
14.60
435
1,281
14.70
506
1,495
14.80
577
1,708
14.90
648
1,922
15.00
719
2,136
15.10
789
2,349
15.20
860
2,563
15.30
931
2,776
15.40
1,002
2,990
15.50
1,073
3,203
15.60
1,144
3,417
15.70
1,214
3,630
15.80
1,285
3,844
15.90
1,356
4,057
16.00
1,427
4,271
16.10
1,498
4,485
16.20
1,569
4,698
16.30
1,640
4,912
16.40
1,710
5,125
16.50
1,781
5,339
16.60
1,852
5,552
16.70
1,923
5,766
16.80
1,994
5.979
16.90
2,065
6.193
17.00
2,136
6,407
17.10
2,206
6,620
17.20
2,277
6,834
17.30
2,348
7,047
17.40
2.419
7,261
17.50
2,490
7,474
17.60
2,561
7,688
17.70
2,631
7,901
17.80
2,702
8,115
17.90
2,773
8,328
18.00
2,844
8,542
18.10
2,915
8,756
18.20
2,986
8,969
18.30
3,057
9,183
18.40
3,127
9,396
18.50
3,198
9,610
18.60
3,269
9,823
18.70
3,340
10,037
18.80
3,411
10,250
18.90
3,482
10,464
19.00
3,553
10,678
19.10
3,623
10,891
Elevation
Surface
Storage
(feet)
(sq-ft)
(cubic -feet)
19.20
3,694
11,105
19.30
3,765
11,318
19.40
3,836
11,532
19.50
3,907
11,745
19.60
3,978
11,959
19.70
4,048
12,172
19.80
4,119
12,386
19.90
4,190
12,599
20.00
4,261
12,813
20.10
4,395
13,306
20.20
4,529
13,799
20.30
4,663
14,292
20.40
4,797
14,785
20.50
4,931
15,278
20.60
5,064
15,771
20.70
5,198
16,264
20.80
5,332
16,757
20.90
5,466
17,250
21.00
5,600
17,744
21.10
5,706
18,330
21.20
5,813
18,917
21.30
5,919
19,503
21.40
6,026
20,090
21.50
6,132
20,677
21.60
6,284
21,328
21.70
6,435
21,979
21M
6,587
22,630
21.90
6,738
23,281
22.00
6,890
23,932
22.10
6,995
24,647
22.20
7,100
25,362
22.30
7,205
26,078
22.40
7,310
26,793
22.50
7,415
27,508
22.60
7,537
28,280
22.70
7,659
29,052
22.80
7,782
29,824
22.90
7,904
30,596
23.00
8,026
31,369
23.10
8,158
32,204
23.20
8,290
33,040
23.30
8,421
33,875
23.40
8,553
34,711
23.50
8,685
35,546
23.60
8,820
36,448
23.70
8,954
37,351
23.80
9,089
38,253
23.90
9,223
39,155
24.00
9,358
40,057

Wrightsville Office Park Type 111 24-hr wilmington 50 year Rainfall=9.01 "
Prepared by {enter your company name here}
HydroCAD® 7.10 s/n 000479 ©2005 HydroCAD Software Solutions LLC 9/11/2006
Estimated Pond Sizing for Pond 2P: retention pond
Time Desired -Peak Required -Storage
(hours)
(cfs)
(acre-feet)
12.30
14.30
0.087
12.50
7.86
0.577
12.70
3.92
0.878
12.90
3.01
0.965
13.10
2.46
1.028
13.30
2.19
1.064
13.50
2.04
1.089
13.70
1.89
1.115
13.90
1.75
1.143
14.10
1.60
1.172
14.30
1.51
1.193
14.50
1.44
1.211
14.70
1.37
1.230
14.90
1.29
1.249
15.10
1.22
1.270
15.30
1.15
1.291
15.50
1.08
1.313
15.70
1.01
1.336
15.90
0.93
1.359
16.10
0.86
1.383
16.30
0.82
1.399
16.50
0.79
1.411
16.70
0.75
1.424
16.90
0.72
1.437
17.10
0.69
1.451
17.30
0.66
1.465
17.50
0.63
1.479
17.70
0.59
1.494
17.90
0.56
1.509
18.10
0.53
1.524
18.30
0.51
1.532
18.50
0.50
1.538
18.70
0.49
1.543
18.90
0.48
1.549
19.10
0.48
1.555
19.30
0.47
1.561
19.50
0.46
1.568
19.70
0.45
1.574
19.90
0.44
1.580
20.10
0.43
1.587
20.30
0.42
1.593
20.50
0.41
1.598
20.70
0.41
1.603
20.90
0.40
1.609
21.10
0.39
1.614
21.30
0.38
1.620
21.50
0.38
1.626
21.70
0.37
1.632
21.90
0.36
1.638
22.10
0.35
1.644
22.30
0.35
1.650
22.50
0.34
1.656
Time Desired -Peak Required -Storage
(hours)
(cfs)
(acre-feet)
22.70
0.33
1.663
22.90
0.33
1.669
23.10
0.32
1.676
23.30
0.31
1.682
23.50
0.30
1.689
23.70
0.30
1.696
23.90
0.29
1.703